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American chambers
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PROCEEDINGS SUPPLEMENTS
Nuclear Physics B (Proc. Suppl.) 36 (1994) 37-58 North-Holland
American Chambers William B. Fowler
Fermi National Accelerator Laboratory, Main Injector Department P.O.Box 500, Batavia, Illinois 60510
Following the discovery of the bubble chamber by Don Glaser, there was immediate recognition by many American high energy physics research groups of the great potential for improved experimentation using bubble chambers. This paper traces the American effort, attempting to include the significant steps (leaving out the AIvarez group's contribution) that lead to the dominance of the bubble chamber technique for high energy physics research for many years.
1. INTRODUCTION
physicists in many laboratories. Within ten years the volume of a typical bubble chamber
Already covered by Don Glaser was the bubble chamber discovery.
Also,
Lynn
Stevenson has described the rapid exploitation
increased by a factor of a million and the use of bubble chambers spread to every laboratory with high energy physics programs.
of the new invention including the major
What were the factors that lead to this
accomplishment of recognizing the importance
rapid proliferation of this new technique. I will
of using liquid hydrogen and implementing
give my personal view of the sequence of
hydrogen chambers for use with the newly
events which served as the basis for this
available Bevatron by Alvarez. My task is to
explosion of activity.
cover the rest of the American chamber
First and foremost was the recognition of
developments. The bubble chamber fitted the
the power of the visual
needs of experimental high energy physics at
experimentation in particle physics.
technique for
larger accelerators and its development and exploitation was soon
pushed by
many
1.1. Visual Technique
An example of how the concept of *Operated
Research
visualization of nuclear particles affected
Association, Inc. under contract with the U.S.
individuals can be found in Leon Lederman's
Department of Energy.
new book, "The God Particle." Lederman
1994
-
by
Universities
Elsevier Science
B.V.
SSDI 0920-5632(94)00526-2
38
WB. Fowler~American chambers
recounts the way in which Anderson's
1.2 Strange Particles and the Diffusion
discovery of the positron influenced him in the
Cloud Chamber
following way 1.
The physicist's ability to study the
"In 1932, a young Cal Tech physicist
properties of strange particles expanded
named Carl Anderson built a cloud chamber
greatly following the observation of machine-
designed
produced
to
register
and
photograph
V
particles.
Protons
were
subatomic particles. A powerful magnet
accelerated by the Cosmotron to 1 GeV in
surrounded his apparatus to bend the path of
May 1952; however, by the time shielding was
the particles, giving a measure of their energy.
added and the target, beam, and detector
Anderson bagged a bizarre new particle
or,
equipment put in place, it was the spring of
in the cloud chamber.
1953. At this point, experimenters could begin
He called this strange new object a positron,
to collect data. As noted below, among the first
because it was identical to an electron except
detectors to be used was the high-pressure
that it had a positive charge instead of a
hydrogen diffusion cloud chamber 2 with an
negative charge. Anderson's publication made
11,000-G magnetic field. In the first 4,000
no reference to Dirac's theory, but the
photographs, with the chamber exposed to a
connection was soon made. He found a new
high-energy neutron beam 3,
form of matter, the antiparticle that had
particles popped up. Two of these had tracks
popped out of the Dirac equation a few years
that
earlier. The tracks were made by cosmic rays,
measurements of sufficient accuracy to be
radiation from particles that strike our
convincing. That lead to the first studies
atmosphere from the far reaches of our
exploiting the advantages the accelerator had
galaxy. Anderson, to get even better data,
over cosmic rays.
rather, the track of one
transported his apparatus from Pasadena to
gave
Recounting
momentum
how
this
several
and
V
angle
development
the top of a mountain in Colorado, where the
occurred; in the summer of 1950, several
air is thin and the cosmic rays are more
groups were experimenting with continuously
intense. A front-page photograph of Anderson
sensitive diffusion cloud chambers, and Ralph
in the New York Times, announcing the
P. Shutt recognized their potential use for
discovery, was an inspiration to the young
Cosmotron experiments, in particular if high-
Lederman, his first exposure to. the romantic
pressure hydrogen could be made to work.
adventure of schlepping equipment to the top
Great enthusiasm and a wide variety of skills
of a high mountain to make important scientific
existed at that time in Shutt's cloud-chamber
measurements."
group, and very shortly two 20-atm hydrogen
excerpt from T l l l i (iC)l) PAI.ITICI,I':, (7,.)pyrighl (c) 1993 I'~y l.con 1 cdcrn',an and Dick Tercsi. Rcpl'ir~Icd h.,, pcrmis'-,i,.;rl ol lloughtc, n Mifflin Company. All rights rcsclx.'cd.
W.B. Fowler~American chambers
39
diffusion chambers had been constructed.
proton collision had produced a neutral V
Through the effort of Gilberto Bernardini this
particle that was identified by its decay. Track
equipment was moved to the Nevis cyclotron,
(b) was unambiguously a proton, and from
where exposures to pion beams demonstrated
momentum and angle measurements the
the usefulness of this new tool. With the
decay was classified as a VI(A ). Because
addition of a new magnet, the high-pressure
momentum and energy are conserved ih the
hydrogen diffusion chamber was on the floor
production, particle (d) could be determined to
of the Cosmotron when the first experiments
be a heavy meson of 1,350!-_70 me, if only one
o
began. Returning to the first observation of artificial production of V's, the maximum energy of an incident neutron was 2.2 GeV, because the Cosmotron energy was known. Various possible production mechanisms were
rd
investigated, and the following conclusion was stated: o Production of V~I, V 2 pairs, would ... be consistent
with the
present
observation. That is, the question of associated production was still open. In those days, it was possible to move the detectors from one beam to another for
1o
different exposures. In fact, the high-pressure hydrogen diffusion chamber's magnet was on wheels, and the experimenters (with the help
Figure 1. The first observation of ~" + p ~ A +
of a few strong technicians) crossed the
0 as seen in the Brookhaven hydrogen
Cosmotron floor and set up in a negative-pion
diffusion cloud chamber. Tracks b and c are
beam
A fantastic
the proton and the pion from the A decay and
photograph 4 appeared one afternoon on the
the arrow labeled d is the direction of the 0
scanning table being used by Alan Thorndike
which did not decay in the sensitive volumn of
(Figure 1). Everyone knew at a glance that
the chamber. The negative pion beam energy
something significant was at hand. The pion-
was 1.5 BeV.
of
1.5 GeV
energy.
W.R Fowler~American chambers
40
other particle was produced with the A. Another event yielded similar results.
1.3 Things That Were Already in Place In addition to the cloud chamber and the
This paper did not claim associated
advent of new high energy accelerators,
production of strange particles. Its carefully
another important development was the use of
worded conclusion was as follows:
emulsions for detecting high energy particle interactions and decays.
Of course, instead of one heavy
In combination this meant that:
particle, several lighter ones (for
(1) More data existed than could be used by
instance two ~0, s or a ~0 and a V1)
one research group.
could originate from the events in o addition to the V 1. However, the
(2) With the onset of electronic computers powerful data analysis was available.
present results are consistent with the o possibility of production of V 1 together with
one
other
heavy
1.4 Looking Ahead
unstable
In order to see what the level of the
particle.
American chamber effort was at its peak, the summary by Joe Ballam 6 that was done in
More running and more scanning clarified the
1970 gives a detailed accounting of picture
situation, so that by November 1953 the group
taking capacity, data analysis capacity and a
submitted
list of U.S. Bubble Chamber Groups.
new data on the associated
production of strange particles in
~'-p
collisions. The reactions seen were x'+p~
A+O
following is a quotation from the Ballam paper: "U.S. bubble chambers by 1970 were almost exclusively cryogenic. There are, for
as well as ~-+p~
The
example, no plans to build large heavy liquid Z-+K +
chambers such as Gargamelle (CERN) or the
Where T_,"was called A ' ( V i ) . This paper 5,
corresponding chamber being constructed at
which reports a Z" decay into a x" + neutron,
Dubna for the Serpukhov accelerator. The
with Q=130 MeV, reports the initial discovery
chambers shown in Table 1 are now in
of the T_,'. Lifetime information, although
operating condition. In addition there are two
sparse, was
further chambers in construction: the NAL 168"
consistent
with the 10 -10 to
3x10 10 sec quoted in the literature at that time.
and the SLAC 15" rapid cycling chamber".
W.B. Fowler~American chambers
41
Table 1 Picture Takinq CaPacity of U. S. Chambers Per Year, Derived From the Formula in the Text Actually taken Laboratory
Chamber
Picture/year
in 1970
SLAC
82"
9 106
4 106
SLAC
40"
9 106
0.5 106
BNL
80"
4 106
1.1 106
BNL
30/31"
4 106
2.6 106
BNL
84"
4 106
....
ANL
30"
4 106
2.3 106
ANL
168"
4 106
....
Total
38 106
10.5 106
Event Rate
7.0 106*
*Assuming 1 event/picture in the 80" and 82", 1/3 event/picture in the others.
1.4.1 Picture Takina CaDacitv
is the number of expansions per pulse
On the basis of a considerable amount of experience with all sorts of chambers, we
is the efficiency (25%)
now have an idea of the efficiency of picture taking, i.e., for the entire system: chamber,
For BNL and ANL
beam and accelerator. The result is that on
R=
the average a chamber will take useful
2.25 x 107 (75% of the calendar time)
pictures for about 25% of the time it is
R
1/3
scheduled to run. Using this efficiency factor,
r
2 (double pulsing)
T=
1.5 x 107 (50% of the
it is possible to calculate the picture taking capacity per year as
where
For SLAC
N=
TRr~
T
is the scheduled time for BC
r
1
running in seconds
R
2 (limited by cameras)
R
is the accelerator pulse rate per second
calendar time)
The result, shown in Table 1 comes out as an impressive 38,000,000/year. I have assumed that BNL would not run the 30" and 31" simultaneously.
WB. Fowler~American chambers
42
If we look at the actual performance in 1970, shown also in Table 1, we find that, excluding the two
not processed.
BNL and ANL
I realize that LRL, BNL and ANL can
chambers, the actual rate is ~1/3 of maximum--
probably do more than 500,000 events/year.
a pretty good record considering financial
But on the other hand, not all the University
limitations as well as difficulties with the 80".
groups
Normalizing to one chamber and to an average
Therefore, I feel that 6,000,000/year is a
number of tracks (as explained in Table 1) this
reasonable estimate. Incidentally, it was not
rate produced about 7,000,000 events/year.
that big in 1970."
1.4.2
large
are uninteresting, unmeasurable or otherwise
D~,taAnalysis CaDacity--U.S. Bubble
can
do
250,000
or
100,000.
2 AMERICAN CHAMBER EFFORTS
Chamber Groups Now what kind of a match is this to the U.S. data analyzing capacity which we hope to have in the near future? Table 2 shows a list of all U.S. bubble chamber groups. I have indicated which of these have automatic measuring devices either in operation or on order. Assume the University groups with automatic measuring equipment can measure 250,000 events/year, that the Institutes do 500,000 events/year, and that the more conventional
systems
do
100,000
events/year. Also assume that 20% of the events are re measures.
The capacity C is
then: C = 0.8 [4 x 500,000 + 16 x 250,000 + 18 x 100,000] = 6,200.000 events/year.
In recognition of the wide diversity of the Bubble Chamber activity in the U.S. it seemed appropriate to collect material from the various groups. On May 11, 1993 I sent a letter to as broad a list as I could come up with requesting
individuals to search their
files to see what materials they might find that could be included in this paper. I wish to express my appreciation to those who took the time and effort to respond. I have selected what seemed to me to be the most appropriate and apologize to the responders whose material could
not be included
because of lack of space.
2.1 Early Work Roger Hildebrand at the University of Chicago repeated Don Glazer result using
This is to be compared with the data taking rate of 7,000,000 events/year. This is a good match since perhaps one half of the events
isopentane and the "clean" glass chamber technique. Figure 2 shows the first track of an electron in a 1 cm chamber built by his
WB. Fowler~American chambers
43
Table 2 U.S,Bubble Chamber Groups 1970 Institutes
*Argonne National Laboratory *Brookhaven National Laboratory *Lawrence Radiation Laboratory *Stanford Linear Accelerator Center Universities
Brandies University
*Calif. Inst. of Technology
Carnegie Inst. of Technology
*Columbia University
*Duke University
Florida State University
*John Hopkins University
*Massachusetts Inst. of Technology
*Purdue University
*Rutgers University
Stevens Inst. of Technology
SUNY Stony Brook
Syracuse University
Tufts University
Vanderbilt University
Western Reserve University
*Yale University
Univ. of Calif., Berkeley
Univ. of Calif., Davis
Univ. of Calif., Irvine
Univ. of Calif., Los Angeles
*Univ. of Calif., Riverside
*Univ. of Colorado
*Univ. of Hawaii
*Univ. of Illinois
*Univ. of Indiana
Univ. of Maryland
Univ. of Massachusetts
Univ. of Michigan
*Univ. of Pennsylvania
*Univ. of Rochester
*Univ. of Washington
Michigan State University
*Univ. of Wisconsin Totals: 34 Universities,
4 Institutes,
38 All
*Now have, either on order or in use, an automatic measuring machine of the types Spiral Reader, PEPR, POLLY, FSK, HPD.
student Irwin Pless. Hildebrand notes that
chamber filled with isopentane to the spill-out
this photograph was shown in his invited talk
beam of the Chicago Synchrocyclotron
at the APS Thanksgiving Meeting in 1954.
whose energy was in excess of 460 Mev.
Hildebrand also provided Figure 3 which
507 events were use in the analysis.
he believes was the first experiment using a
The Chicago group moved rapidly to
bubble chamber. Pless 7, working under
liquid hydrogen, not only helping to show that
Hildebrand with the assistance of Dick Piano,
liquid hydrogen was a useful filling for bubble
exposed a 13 mm x 27 mm x 27 mm glass
chambers
but
also
carried
out
an
W.B. Fowler~American chambers
44
Figure 2. Hildebrands first tracks in glass
Figure 3. First experiment with a Bubble
chamber
Chamber. A proton-proton scattering is seen
1 cm in diameter filled with
isopentane (1954).
in the isopentane liquid using the Chicago Cyclotron.
The stereo photograph was
obtained operating at 460 Mev. (1955).
experiment 8 using an 18.7 MeV negative
use the device for physics. They built a 10-
pion beam at the University of Chicago
cm diameter propane chamber which was
cyclotron,
immediately replaced by a 15-cm diameter propane chamber that was used without
2.2. The Columbia Group In 1954 Jack Steinberger and three
magnetic field at the newly commissioned Brookhaven Cosmotron.
graduate students, J. Leitner, N.P. Samios
A number of results were obtained on the
and M. Schwartz, began to study the bubble
properties of the new unstable (strange)
chamber technique which had just been
particles at an event rate unattainable with
discovered by Glaser. Their interest was to
older techniques. This began a new phase in
WB. Fowler~American chambers
45
high energy physics experimentation where
--the determination of the co and ~ decay
the bubble chamber dominated particle
widths (lifetimes), 1962
physics for the next dozen years.
--the determination of the Z 0 - - A 0 relative
This group published three events of the
parity, 1963
type Z 0 ~ A ° + 7, which proved the existence
--the
of the Z 0 hyperon and gave a measure of its
the
mass. This experiment used a new propane
AS-
chamber, eight times larger in volume, and
1964.
with magnetic field. This chamber also
Two Italian groups, the Bologna group of G.
introduced the use of more than two stereo
Puppi and the Pisa group of M. Conversi,
cameras, a development important for the
participated
rapid, computerized analysis of events.
experiments. The first Columbia hydrogen
Subsequent bubble chambers incorporated at
bubble chamber is shown in Figure 4.
least three views.
demonstration of
the
validity
of
AQ rules in K 0 and in hyperon decays,
in
some
of
the
above
AI Prodell provided data on the 170-liter
For ten years, the Columbia group played
heavy liquid bubble chamber 9 built by the
a major role in bubble chamber construction
Columbia group. The volume occupied by the
and experimentation.
Professors Piano,
liquid is a section of a truncated cone 15 in.
Baltay, Franzini, Colley and Prodell, and a
deep with a 15 in. radius at the back of the
nunber
the
chamber and a 14 in. radius at the single
collaboration. They constructed three more
glass window, which is 4 inches thick. The
bubble chambers: a 12" H2 chamber as well
magnetic field is 15 kG and the magnet was
as 30" propane and H2 chambers, developed
later used with the 30" Columbia-Brookhaven
the analysis techniques, and performed a
hydrogen chamber constructed later. Figure 5
series of experiments to clarify the properties
shows a schematic view of this chamber.
of the
of
new
students
new particles.
joined
Some
important
One final note which I found interesting
experiments of this period are:
concerning the Columbia
--the demonstration of parity violation in A
chamber effort came from Norman Gelfand.
decay, 1957
He pointed out that bubble chamber film
--the demonstration of the 8 decay of the
analysis
pion, 1958
experimenters
--the determination of the ~0 parity on the
individual
basis of angular correlation in the double
Gelfand studied the annihilation of stopped
internal conversion of the gamma rays, 1962
antiprotons in hydrogen. He reported 1° in the
was
divided
group bubble
up
among
and there was a lot of
effort possible.
For instance,
W.B. Fowler~American chambers
46
"4 w 4 v
~
F N ~ 0 ¥4LvE
V4
4NOER
ol
LIGMT 5OunCE
/
CONDENSING L Et~5
dME..R4 EA'$
Figure 4. The first Columbia Hydrogen bubble chamber, 12 inches in diameter in a magnetic field of 13.4 kG.
HEATER
-"-
\"
Physical Review, under his sole name, the
/
X
results of 1193 events accumulated in the Columbia-Brookhaven 30" hydrogen bubble
/
CHAMBE~R
,E::CLE
yOKE
chamber for the purpose of studying i~p annihilation
at
rest
into
~+~-~o. A
considerable contrast to todays lists of hundreds of authors reporting colliding detector results.
2.3. The Adair Group One of the most interesting responses to Figure 5. Schematic view of 170- liter heavy
the request for information about American
liquid bubble chamber assembly built by the
bubble chamber history came from Bob Adair
Columbia group.
~B. Fowler~American chambers
at Yale. Perhaps the best way to present his views is to quote from his letter.
47
"The chamber was relatively unique for that time, in that a piston was used for
"To think now about the old bubble-
expansion. In that early time, I had to invent
chamber days is, for me, a pleasant trip down
my own instrumentation (though that was not
memory lane.
necessarily
different
than what others
invented at the same time.) Hence, I put in a "1 came to BNL in the fall of 1953 with a
capacitative diaphragm to measure the
background in classical nuclear physics. After
pressure change on expansion, a hydrogen
some abortive essays in emulsion with Ed
vapor pressure thermometer to determine the
Salant and with electronics with Dick Madey,
temperature and a resistor chain in the
I got involved with building hydrogen targets
hydrogen reservoir to measure the depth of
with AI Schlafke and learned a little about
hydrogen in the reservoir.
hydrogen. Then I decided to move to
"At the time it first operated, I think that
hydrogen bubble chambers thinking that they
only Louis AIvarez's chamber of roughly the
were so new that, at any rate, I wouldn't be
same size -- and expanded quite differently --
far behind anyone technically.
was running though the tiny chamber that
"Then, some time about the fall of 1954, I
Roger Hildebrand and (Piano and Pless) had
began the design and construction of a small
operated in a measurement of pi-p scattering
hydrogen chamber with a new technician,
was the very first H-chamber.
Rich Larsen, and with Lyle Smith, Lyle was so busy with machine operations, etc. that he
"Late in 1956? Leipuner, Larsen , and I,
wasn't able to spend much time at the project
began to design a larger chamber with a field.
but what time he did spend was valuable.
This was 14" in diameter in a magnet and
Roughly September 1955, larsen and 1
was finished, I would guess, at the end of
finished the chamber and ran it with colbalt
1957 (here my dates are fuzzy). I guess one
60 -- and it worked. (I recount seeing tracks
could better date it by the completion of the
in the chamber as one of mv areatest instant
20". We were a few months ahead -- so that
thrills in physics.)"
for a few months we had the second biggest
Many of us no doubt share in this
hydrogen bubble chamber in the world;
recounting of seeing the first tracks of
second to the Berkeley 15" chamber (which
charged
in bubble chambers.
was, however, somewhat deeper). As I recall,
Continuing with the quote from the Adair
the total capital cost of our chamber and
letter.
magnet was not much more than $50,000.
particles
W.B. Fowler~American chambers
48
"We used this chamber to look at Ko-p
2.4. The MURA-ANL-Fermilab 30"
interactions where we 'discovered' the Yo
Hydrogen Bubble Chamber
(Phys. Rev. Letters 6, 283 (1961). (We were
The project to construct the 30" began
only a little behind Alverez who saw the
with a succession of propane chambers that
charged Y's.) Then, we looked at a large flux
were constructed at Wisconsin beginning in
of K-L's (Phys. Rev. 132, 2285 (1063)), we
1955. These chambers ranged in size from a
examined Ko decays and saw a hint of what
couple of inches in diameter up to a 15 '°
was shown later by Fitch and Cronin to be
diameter propand-freon chamber. In 1958
CP=violation.
Walker and Ballam proposed a 30" heavy
"During this period, others used our
liquid chamber to be used at the cosmotron
chamber also with Rich Larsen running the
but Steinberger won out and constructed the
show. The most important result, was the
30" propane and 30" hydrogen chambers you
discover of the rho-0 by Walker and Erwin but
have already heard about.
others, Leona Marshall and Dave Barge, and Walter Selove, also used the chamber.
hydrogen chamber that discovered the p
"Technically, the chamber had a level of followers
in
chambers
built
by
After working with Adair using the 15"
meson at BNL, Walker turned his attention to
Ned
the 30" which turned out to be one of the
Goldwasser and Lou Koester at Illinois and
most productive chambers used first at the
by Erwin and Walker at Wisconsin. Also, later
Argonne ZGS and later at Fermilab. Walker
Fred Eisler looked at K-decays at the AGS --
reports that from 1964 to the end of the
and found CP violation effects like the kind
running at Argonne there were 64 Phys. Rev.
we saw but he wanted to prove we were
Letters and 114 articles from 16 institutions.
wrong so he never published his results (but we did. Physics Letters 12, 67 (1964). "We never wrote an engineering, or
Of interest is the January 1960 proposal which Walker provided a copy of sets a budget of $370,000 for materials
and
instrumentation, paper on the chamber. With
$188,000 for
a small group (of three, Larsen, Leipuner,
physicists, 2 engineers, 2 draftsmen, 10
and I) we couldn't seem to break away from
machinists and 8 technicians man years.
physics to do the engineering analyses
Figure 6 shows a schematic of the MURA-
desirable for a chamber paper.
ANL-Fermilab 30 inch.
"Anyway, it was great fun while it lasted."
labor,
which
included
4
The excellent picture quality that this chamber was capable of is shown in Figures 7 and 8. Table 3 shows the wide diversity of
H(B. Fowler~American chambers
49
L
ChamberExpansionPistons (3 in line)
MagnetCoil (waterand electrical connections
•
MagnetSteel~ ChamberWindows(34' O.D.)--. CondensingLenses~l~ Liquid NitrogenThermalSt Vacuum Can ' Xenon Fbsh Tubl Housing
")"
Hydrogen Observation Port
~
sCamera Lens and Mirror Housin9
Vacuum Pure
CameraFilm ~zlne I~rtk:~ enter)"
I
;E
Figure 6. Schematic view of the MURA-ANL-Fermilab 30 inch hydrogen bubble chamber.
beams and users of the MURA-ANL-Fermilab
fluid caused problems due to index of
chamber by presenting a list of experiments
refraction variations from temperature non-
and number of pictures taken at Fermilab.
uniformities; however, the chamber turned out to be quite useful. The sensitive volume
2.5 Wilson Powell's 30" Propane Chamber Propane
chambers
were
pursued
was 30.5" x 21.5" x 6.5" with a magnetic field of 14,000 gauss.
because they were faster to build. Powelrs
Powell invented the use of Scotchlite
group built the first large propane chamber by
beads for brightfield chamber illumination,
using hydrostatic support rather than a large
after starting out with a plastic retrodirector.
thick window. The oil used as the support
This scheme worked extremely well and was
7
WB. Fowler~American chambers
50
Figure 7. A 5.5 GeV/c K" beam in MURA-ANL-Fermilab 30" hydrogen chamber taken in 1965 at ANL.
in fact one of the enabling advances in
"The chamber was used early on to
bubble chamber technology that allowed for
produce the E', in a 5 GeV =" beam, one of
the development of the giant chambers to be
the first pictures of that particle. The chamber
described by M. Derrick later in the program.
was used to look at antiprotons, and the
Bob Birge provided a summary of the 30" propane chamber use in experiments.
charge exchange to produce antineutrons. (Figure 9 shows the first example of an antiproton charge exchanging to yield an
51
W.B. Fowler~American chambers
\ higan
Rochester Collaboration~
May, 1973
tG~V3~!it°h Hy~r°~°nn I B n ~ c ~ i ° n b e ~ \ National Accelerator Laboratory
~/
/ /
/
P +
/,
:
=-+ (19 charged particles)
i
L~-+
Ao
I
L_~ p + ~-
I I
...': /
-
..:
" - ~ .... -
,
i
~:.
_
/
=. . ..............................
. . . . .
~
,/ .
/
_ .........
...........-"-: . . . . . . . . . . . . . . . c'-:....~ ............. ,......... ~ , . . ~ - - -
• ...~,-~:.. ~ / .................................................................... ~ ......=..::;.::. ;; " ~ _ ~ . ~ : : . , y . ! : ; 2 . :
•
x = -.38 PT = 0.58 GeV/e
/
~
................ '................. ~<-:
_~ particle
............... ---.~..~.-.:"'7-m _ _ ~
~ ' " - ~ . - .
--
-. . . . . . .
-~ :.-:."
. _,..=.,,=~'--'..".~; ...,:~...C~,~.~:,.:.=.,c._:.-~..-:/~:.::::..._,.~....T
; . . . . .
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_ .._-.,:'-
~ .......... ;_,_.-~:~F..-;? ........... :
. ~,. . . . . ~. . . . . . . . . . . . . . . -~..,..,_~---~.---.;;,~__,--:,: ;~:
: ......
"-:""""~" ~ - = " ~ -
.-:--:
" " -: ~-~=-,'~ c-, n ~ ~
:"z~
.... ~--, . . . . . ; .............k ~\................................. ---:U;-}"-<-. L'--'; . . . . . .T-.:::-.:;:-Z. .~ . . . . !. . . . . . . . . . . . . . - __.~.~.-:zT.-~ -.,~.. . . . . . . .. 'X
°
. ~
.....
'
"",~.
-... ...... ;.
Figure 8. A 405 GeV Proton beam at Fermilab showing production of F," taken in May 1973 with MURA-ANL-Fermilab 30" hydrogen chamber.
antineutron which then annihilates in the
Bud Good's original idea, with Piccioni
liquid propane creating multiple tracks, whose
pushing to do the experiment, and was Bob
energy proves that it was an antineutron).
Good's thesis.
Then there were many runs on stopping K +, including experiments on the Ke4 decay, and
"Eventually the chamber was put into a o K" beam and the spin of the Y1 was
K!13, looking for time reversal invariance and
measured along with parameters of the
form factors. The most interesting experiment
Lambda Hyperon."
to me was the run on Regeneration and Mass Difference of Neutral K Mesons, where we installed a 6" thick tungsten block in the chamber to regenerate K~S(o,1), from a beam o of K 2, in a forward diffration peak. This was
2.6. Helium Chambers
Martin Block took on this very difficult technique early on and worked with
52
WB. Fowler~American chambers
Table 3 Thirtv (30~ inch hvdro(]en chamber runs at Fermilab Number
Experiment Number
Beam
Spokesperson
Status
of Pics
2B
Hybrid
Smith
Completed
479 K Pix
37A
P-P @ 300
Malamud
Completed
51 K Pix
121A
PI+ @ P-P @ 100
Lander
Completed
104 K Pix
125
PI--P @ 100
Morrison
Completed
53 K Pix
137
PI--P @ 200
Huson
Completed
48 K Pix
138
P-P @ 400
Vander Velde
Completed
52 K Pix
141A
P-P @ 200
Fields
Completed
67 K Pix
143A
PI--P @ 300
Mulholland
Completed
51 K Pix
154
Hybrid
Pless
Completed
105 K Pix
161
P-P & NE @ 300
Mapp
Completed
51 K Pix
163A
PI--P & NE @ 200
Walker
Completed
52 K Pix
194
P- D @ 100
Murphy
Completed
92 K Pix
196
P - D @ 400
Engelmann
Completed
109 K Pix
209
P- D @ 300
Dao
Completed
106 K Pix
217
PI+ & P-P @ 200
Lander
Completed
85 K Pix
218
PI--D @ 200
Yager
Completed
72 K Pix
228
PI+ & P-P @ 60
Ferbel
Completed
37 K Pix
252
P-P @ 100
Ferbel
Completed
33 x K Pix
280
P- D @ 200
Fields
Completed
103 K Pix
281
Hybrid
Smith
Com ~leted
301 K Pix
295
PI+ & P-D @ 200
Yekutieli
Corn ~leted
156 K Pix
299
Hybrid
Pless
Com ~leted
431 K Pix
311
Pbar-P @ 100
Neale
Com ~leted
98 K Pix
338
PI--D @ 360
Moriyasu
Com ~leted
53 K Pix
344
Pbar-P @ 50
Gutay
Com ~leted
145 K Pix
345
Pbar-D @ 100
Ekspong
Com ~leted
61 K Pix
570
Hybrid
Pless
Com ~leted
1,068 K Pix
597
Hybrid
Whitmore
Com ~leted
658 K Pix
TOTAL
4.688 K Pix
~B. Fowler~American chambers
53
Figure 9. An antiproton enters the bubble chamber from the top. Its track disappears at the arrow as its charge exchanges ~ ~ nn. The antineutron produces the star seen in the lower portion of the picture. The energy released in the star was greater than 1500 MeV.
Fairbanks and Harth and later with Pevsner
sheets of floating glass windows similar to
and Puppi.
superinsulation technology.
Block points out that Fairbanks' cryogenic
One of the interesting occurances was
experience was important in being able to
when they were first set up to run on the
overcome many of the problems. They were
Cosmotron the Cosmotron had a major
the first to use indium gaskets and schlieren
magnet failure and Block contacted Alvarez
photography. They also used multipole
and arranged to transport
the
helium
chamber to Berkeley where they set-up and
W.B. Fowler~American chambers
54
ran using the Bevatron. Block thinks that they
As mentioned before, the Shutt group
were probably the first outside user group at
was the leader in the use of high pressure
LBL. This no doubt lead to their use of 72"
diffusion cloud chambers at the new higher
film for the famous
energy accelerators that came into being
Pevsner-Block
eta
following
experiment. The Northwestern group designed and
World
War
I1. When
Glaser
discovered the bubble chamber, the Shutt
built the 50 cm He chamber 11 first tested in
group
October 1965.
importance of this new technique. Their
There were other helium chamber efforts
at
Brookhaven
recognized
the
interest was in hydrogen and in chambers
in the U.S. and Tom Fields provided an
with
small
bubble
size
and
minimum
example of K" stopping in the 10" ANL\CMU
distortion due to liquid motion or index of
helium chamber taken in 1966. Previously
refraction variations. The 20-inch piston
they had a 6" He chamber that operated for
expanded hydrogen bubble chamber was the
the first time in 1960.
result of considerable effort to accomplish
Also to be noted is that the Carnegie
these objectives, and was brought into use
group built a 6" hydrogen chamber (first
when the Brookhaven Alternating Gradient
physics run 1957) and an 8" propane
Synchrotron first operated. Simultaneous with
chamber (first physics run 1957) used for
the experimental runs using the 20 inch, the
absorption of negative muons in C12 leading
work toward the larger 80 inch was initiated in
to production of bound B12, which required
1959. The 80 inch (Figure 11) consists of a
-20 millisec sensitive time. This same group plus ANL physicists
vessel 80 inches long in the direction of the
made the important step of constructing the
particle path, filled with liquid hydrogen,
first
a
insulated with vacuum and placed in a
superconducting magnet. The 10" ANL\CMU
magnetic field of 20,400 gauss. The 80 inch
superconducting magnet helium chamber
had its first cool-down in May 1963 and the
had a 41 kg field and yielded 18 physics
first tracks were seen on June 2, 1963. The
papers. Figure 10 shows a schematic view of
first experiment was an exposure in a
this chamber in its superconducting coils.
separated 5 GeV K" beam. The start of that
bubble
chamber
that
used
run was December 14, 1963 and after 2.7. The Brookhaven 80 Inch Hydrogen Bubble Chamber
133,000 photos the ~" was discovered late in January 1964. The data on the event made the Physical Review Letters of February 24,
W.B. Fowler~American chambers
1964, and you might hear more of this later from Nick Samios. However, since I am first I
55
4. W.B.Fowler, R.P.Shutt, A.M.Thorndike, 0 and W.L.Whittemore, "Production of V 1
get to show it first, see Figure 12.
Particles
During 11 years of operation, the 80 inch
by
Negative
Pions
in
Hydrogen", Phys. Rev. 91 (1953), 1287.
produced ~12x106 pictures; 27% were
5. W.B.Fowler, R.P.Shutt, A.M.Thorndike,
analyzed by BNL scientist and 73% by
and W.L.Whittemore, "Production of
university users groups. Operation of the 80
Heavy Unstable Particles by 1.37 GeV
inch was terminated in October 1974 due to a
Pions", Phys. Rev. 98 (1995), 121-30.
budget crunch.
6. J.Ballam in Proceedings of the Joint Japanese-U.S. Seminar on Elementary
REFERENCES
Particle Physics with Bubble Chamber
1. From "The God Particle" copyright @ 1993
Detectors, SLAC-144, March 1972, pp
by Leon Lederman and Dick Teresi,
20-1, 20-15.
published by Houghton Mifflin Co., N.Y.,
7.
N.Y.
8. D.E.Nagle,
2. W.B.Fowler, R.P.Shutt, A.M.Thorndike and W.L.Wittemore, "Diffusion Cloud Chambers for Cosmotron Experiments", Rev. Sci. Instrum. 25 (1954), 996-1003. 3. W.B.Fowler, R.P.Shutt, A.M.Thorndike and W.L.Whittemore, "Observation of V0 Particles Produced at the Cosmotron", Phys. Rev. 90 (1953), 1126-7.
I.Pless, Phys. Rev. 104, (1956), 205. R.H.Hildebrand
and
R.J.Plano, CERN Symposium, Vol. 2 (1956). 9. A.Prodell, Rev. Sci. Inst. 33, (1962), 1327. 10. N.Gelfand, Phys.Rev. 169 (1968), 1077. 11. R.Walker, et al., Rev. Sci. Inst. 39 (1968), 1407.
~B. Fowler~American chambers
56
REFLE EX v---4l-
, Q..~
-----i
I0" BUBBLE CHAMBER
:
'
ASS WINDOW
.-,-------CAMERA LIGHT S O U R C E ~
PLASTIC LENS WINDOW
SUPERCONDUCTING MAGNET
~
N
Figure 10. The ANL 10" helium bubble chamber with superconducting coils.
2 SHIELD
~B. Fowler~American chambers
57
Q HYDROGEN CHAMBER Q MAIN WINDOW (~CYLINDER ( ~ PtSTON Q NECK ( ~ VACUUM CHAMBER Q CAMERAS ( ~ LIGHT SOURCE Q REFLECTORS ( ~ MAGNET
: t::i
ii:,
i
q:
Q EXPANSION SYSTEM
(~HIGH VACUUM P U M P S
cl
(~
YOKE
\
•
..__1
!'
r.::L
.1
ii
J ......
w
Figure 11 Schematic view of the Brookhaven 80 inch bubble chamber. The particle beams are / to this view.
58
W.B, Fowler~American chambers
/ j
.-// / /
J
/
~2 (8)
I II ~ o
K°I I
?
(4)
(3) K-
(i)
Figure 12. On the left is the photograph of the event taken in the 80-inch bubble chamber, with its reconstructed drawing on the right where neutral particles are indicated by broken lines. One of several incoming K minus particles from the accelerator beam collided with a proton and created a neutral K zero meson (K°), a K plus meson curving to the left, and an Omega minus (~') that after about 10 1 0 second decays into a Pi minus (~') and a neutral Xi zero (E 0) particle. The ~0 is identified by the disintegration of its neutral decay products; two gamma rays (y and Y2) that give rise to positron-electron pairs, and a Lambda zero (A 0) that yields a ~" and a proton (p). Knowledge of the masses and momenta of the charged decay products of neutral particles that leave no tracks made it possible to identify the third particle emerging from the initial collision as a K °.
PROCEEDINGS SUPPLEMENTS
Nuclear Physics B (Proc. Suppl.) 36 (1994) 37-58 North-Holland
American Chambers William B. Fowler
Fermi National Accelerator Laboratory, Main Injector Department P.O.Box 500, Batavia, Illinois 60510
Following the discovery of the bubble chamber by Don Glaser, there was immediate recognition by many American high energy physics research groups of the great potential for improved experimentation using bubble chambers. This paper traces the American effort, attempting to include the significant steps (leaving out the AIvarez group's contribution) that lead to the dominance of the bubble chamber technique for high energy physics research for many years.
1. INTRODUCTION
physicists in many laboratories. Within ten years the volume of a typical bubble chamber
Already covered by Don Glaser was the bubble chamber discovery.
Also,
Lynn
Stevenson has described the rapid exploitation
increased by a factor of a million and the use of bubble chambers spread to every laboratory with high energy physics programs.
of the new invention including the major
What were the factors that lead to this
accomplishment of recognizing the importance
rapid proliferation of this new technique. I will
of using liquid hydrogen and implementing
give my personal view of the sequence of
hydrogen chambers for use with the newly
events which served as the basis for this
available Bevatron by Alvarez. My task is to
explosion of activity.
cover the rest of the American chamber
First and foremost was the recognition of
developments. The bubble chamber fitted the
the power of the visual
needs of experimental high energy physics at
experimentation in particle physics.
technique for
larger accelerators and its development and exploitation was soon
pushed by
many
1.1. Visual Technique
An example of how the concept of *Operated
Research
visualization of nuclear particles affected
Association, Inc. under contract with the U.S.
individuals can be found in Leon Lederman's
Department of Energy.
new book, "The God Particle." Lederman
1994
-
by
Universities
Elsevier Science
B.V.
SSDI 0920-5632(94)00526-2
38
WB. Fowler~American chambers
recounts the way in which Anderson's
1.2 Strange Particles and the Diffusion
discovery of the positron influenced him in the
Cloud Chamber
following way 1.
The physicist's ability to study the
"In 1932, a young Cal Tech physicist
properties of strange particles expanded
named Carl Anderson built a cloud chamber
greatly following the observation of machine-
designed
produced
to
register
and
photograph
V
particles.
Protons
were
subatomic particles. A powerful magnet
accelerated by the Cosmotron to 1 GeV in
surrounded his apparatus to bend the path of
May 1952; however, by the time shielding was
the particles, giving a measure of their energy.
added and the target, beam, and detector
Anderson bagged a bizarre new particle
or,
equipment put in place, it was the spring of
in the cloud chamber.
1953. At this point, experimenters could begin
He called this strange new object a positron,
to collect data. As noted below, among the first
because it was identical to an electron except
detectors to be used was the high-pressure
that it had a positive charge instead of a
hydrogen diffusion cloud chamber 2 with an
negative charge. Anderson's publication made
11,000-G magnetic field. In the first 4,000
no reference to Dirac's theory, but the
photographs, with the chamber exposed to a
connection was soon made. He found a new
high-energy neutron beam 3,
form of matter, the antiparticle that had
particles popped up. Two of these had tracks
popped out of the Dirac equation a few years
that
earlier. The tracks were made by cosmic rays,
measurements of sufficient accuracy to be
radiation from particles that strike our
convincing. That lead to the first studies
atmosphere from the far reaches of our
exploiting the advantages the accelerator had
galaxy. Anderson, to get even better data,
over cosmic rays.
rather, the track of one
transported his apparatus from Pasadena to
gave
Recounting
momentum
how
this
several
and
V
angle
development
the top of a mountain in Colorado, where the
occurred; in the summer of 1950, several
air is thin and the cosmic rays are more
groups were experimenting with continuously
intense. A front-page photograph of Anderson
sensitive diffusion cloud chambers, and Ralph
in the New York Times, announcing the
P. Shutt recognized their potential use for
discovery, was an inspiration to the young
Cosmotron experiments, in particular if high-
Lederman, his first exposure to. the romantic
pressure hydrogen could be made to work.
adventure of schlepping equipment to the top
Great enthusiasm and a wide variety of skills
of a high mountain to make important scientific
existed at that time in Shutt's cloud-chamber
measurements."
group, and very shortly two 20-atm hydrogen
excerpt from T l l l i (iC)l) PAI.ITICI,I':, (7,.)pyrighl (c) 1993 I'~y l.con 1 cdcrn',an and Dick Tercsi. Rcpl'ir~Icd h.,, pcrmis'-,i,.;rl ol lloughtc, n Mifflin Company. All rights rcsclx.'cd.
W.B. Fowler~American chambers
39
diffusion chambers had been constructed.
proton collision had produced a neutral V
Through the effort of Gilberto Bernardini this
particle that was identified by its decay. Track
equipment was moved to the Nevis cyclotron,
(b) was unambiguously a proton, and from
where exposures to pion beams demonstrated
momentum and angle measurements the
the usefulness of this new tool. With the
decay was classified as a VI(A ). Because
addition of a new magnet, the high-pressure
momentum and energy are conserved ih the
hydrogen diffusion chamber was on the floor
production, particle (d) could be determined to
of the Cosmotron when the first experiments
be a heavy meson of 1,350!-_70 me, if only one
o
began. Returning to the first observation of artificial production of V's, the maximum energy of an incident neutron was 2.2 GeV, because the Cosmotron energy was known. Various possible production mechanisms were
rd
investigated, and the following conclusion was stated: o Production of V~I, V 2 pairs, would ... be consistent
with the
present
observation. That is, the question of associated production was still open. In those days, it was possible to move the detectors from one beam to another for
1o
different exposures. In fact, the high-pressure hydrogen diffusion chamber's magnet was on wheels, and the experimenters (with the help
Figure 1. The first observation of ~" + p ~ A +
of a few strong technicians) crossed the
0 as seen in the Brookhaven hydrogen
Cosmotron floor and set up in a negative-pion
diffusion cloud chamber. Tracks b and c are
beam
A fantastic
the proton and the pion from the A decay and
photograph 4 appeared one afternoon on the
the arrow labeled d is the direction of the 0
scanning table being used by Alan Thorndike
which did not decay in the sensitive volumn of
(Figure 1). Everyone knew at a glance that
the chamber. The negative pion beam energy
something significant was at hand. The pion-
was 1.5 BeV.
of
1.5 GeV
energy.
W.R Fowler~American chambers
40
other particle was produced with the A. Another event yielded similar results.
1.3 Things That Were Already in Place In addition to the cloud chamber and the
This paper did not claim associated
advent of new high energy accelerators,
production of strange particles. Its carefully
another important development was the use of
worded conclusion was as follows:
emulsions for detecting high energy particle interactions and decays.
Of course, instead of one heavy
In combination this meant that:
particle, several lighter ones (for
(1) More data existed than could be used by
instance two ~0, s or a ~0 and a V1)
one research group.
could originate from the events in o addition to the V 1. However, the
(2) With the onset of electronic computers powerful data analysis was available.
present results are consistent with the o possibility of production of V 1 together with
one
other
heavy
1.4 Looking Ahead
unstable
In order to see what the level of the
particle.
American chamber effort was at its peak, the summary by Joe Ballam 6 that was done in
More running and more scanning clarified the
1970 gives a detailed accounting of picture
situation, so that by November 1953 the group
taking capacity, data analysis capacity and a
submitted
list of U.S. Bubble Chamber Groups.
new data on the associated
production of strange particles in
~'-p
collisions. The reactions seen were x'+p~
A+O
following is a quotation from the Ballam paper: "U.S. bubble chambers by 1970 were almost exclusively cryogenic. There are, for
as well as ~-+p~
The
example, no plans to build large heavy liquid Z-+K +
chambers such as Gargamelle (CERN) or the
Where T_,"was called A ' ( V i ) . This paper 5,
corresponding chamber being constructed at
which reports a Z" decay into a x" + neutron,
Dubna for the Serpukhov accelerator. The
with Q=130 MeV, reports the initial discovery
chambers shown in Table 1 are now in
of the T_,'. Lifetime information, although
operating condition. In addition there are two
sparse, was
further chambers in construction: the NAL 168"
consistent
with the 10 -10 to
3x10 10 sec quoted in the literature at that time.
and the SLAC 15" rapid cycling chamber".
W.B. Fowler~American chambers
41
Table 1 Picture Takinq CaPacity of U. S. Chambers Per Year, Derived From the Formula in the Text Actually taken Laboratory
Chamber
Picture/year
in 1970
SLAC
82"
9 106
4 106
SLAC
40"
9 106
0.5 106
BNL
80"
4 106
1.1 106
BNL
30/31"
4 106
2.6 106
BNL
84"
4 106
....
ANL
30"
4 106
2.3 106
ANL
168"
4 106
....
Total
38 106
10.5 106
Event Rate
7.0 106*
*Assuming 1 event/picture in the 80" and 82", 1/3 event/picture in the others.
1.4.1 Picture Takina CaDacitv
is the number of expansions per pulse
On the basis of a considerable amount of experience with all sorts of chambers, we
is the efficiency (25%)
now have an idea of the efficiency of picture taking, i.e., for the entire system: chamber,
For BNL and ANL
beam and accelerator. The result is that on
R=
the average a chamber will take useful
2.25 x 107 (75% of the calendar time)
pictures for about 25% of the time it is
R
1/3
scheduled to run. Using this efficiency factor,
r
2 (double pulsing)
T=
1.5 x 107 (50% of the
it is possible to calculate the picture taking capacity per year as
where
For SLAC
N=
TRr~
T
is the scheduled time for BC
r
1
running in seconds
R
2 (limited by cameras)
R
is the accelerator pulse rate per second
calendar time)
The result, shown in Table 1 comes out as an impressive 38,000,000/year. I have assumed that BNL would not run the 30" and 31" simultaneously.
WB. Fowler~American chambers
42
If we look at the actual performance in 1970, shown also in Table 1, we find that, excluding the two
not processed.
BNL and ANL
I realize that LRL, BNL and ANL can
chambers, the actual rate is ~1/3 of maximum--
probably do more than 500,000 events/year.
a pretty good record considering financial
But on the other hand, not all the University
limitations as well as difficulties with the 80".
groups
Normalizing to one chamber and to an average
Therefore, I feel that 6,000,000/year is a
number of tracks (as explained in Table 1) this
reasonable estimate. Incidentally, it was not
rate produced about 7,000,000 events/year.
that big in 1970."
1.4.2
large
are uninteresting, unmeasurable or otherwise
D~,taAnalysis CaDacity--U.S. Bubble
can
do
250,000
or
100,000.
2 AMERICAN CHAMBER EFFORTS
Chamber Groups Now what kind of a match is this to the U.S. data analyzing capacity which we hope to have in the near future? Table 2 shows a list of all U.S. bubble chamber groups. I have indicated which of these have automatic measuring devices either in operation or on order. Assume the University groups with automatic measuring equipment can measure 250,000 events/year, that the Institutes do 500,000 events/year, and that the more conventional
systems
do
100,000
events/year. Also assume that 20% of the events are re measures.
The capacity C is
then: C = 0.8 [4 x 500,000 + 16 x 250,000 + 18 x 100,000] = 6,200.000 events/year.
In recognition of the wide diversity of the Bubble Chamber activity in the U.S. it seemed appropriate to collect material from the various groups. On May 11, 1993 I sent a letter to as broad a list as I could come up with requesting
individuals to search their
files to see what materials they might find that could be included in this paper. I wish to express my appreciation to those who took the time and effort to respond. I have selected what seemed to me to be the most appropriate and apologize to the responders whose material could
not be included
because of lack of space.
2.1 Early Work Roger Hildebrand at the University of Chicago repeated Don Glazer result using
This is to be compared with the data taking rate of 7,000,000 events/year. This is a good match since perhaps one half of the events
isopentane and the "clean" glass chamber technique. Figure 2 shows the first track of an electron in a 1 cm chamber built by his
WB. Fowler~American chambers
43
Table 2 U.S,Bubble Chamber Groups 1970 Institutes
*Argonne National Laboratory *Brookhaven National Laboratory *Lawrence Radiation Laboratory *Stanford Linear Accelerator Center Universities
Brandies University
*Calif. Inst. of Technology
Carnegie Inst. of Technology
*Columbia University
*Duke University
Florida State University
*John Hopkins University
*Massachusetts Inst. of Technology
*Purdue University
*Rutgers University
Stevens Inst. of Technology
SUNY Stony Brook
Syracuse University
Tufts University
Vanderbilt University
Western Reserve University
*Yale University
Univ. of Calif., Berkeley
Univ. of Calif., Davis
Univ. of Calif., Irvine
Univ. of Calif., Los Angeles
*Univ. of Calif., Riverside
*Univ. of Colorado
*Univ. of Hawaii
*Univ. of Illinois
*Univ. of Indiana
Univ. of Maryland
Univ. of Massachusetts
Univ. of Michigan
*Univ. of Pennsylvania
*Univ. of Rochester
*Univ. of Washington
Michigan State University
*Univ. of Wisconsin Totals: 34 Universities,
4 Institutes,
38 All
*Now have, either on order or in use, an automatic measuring machine of the types Spiral Reader, PEPR, POLLY, FSK, HPD.
student Irwin Pless. Hildebrand notes that
chamber filled with isopentane to the spill-out
this photograph was shown in his invited talk
beam of the Chicago Synchrocyclotron
at the APS Thanksgiving Meeting in 1954.
whose energy was in excess of 460 Mev.
Hildebrand also provided Figure 3 which
507 events were use in the analysis.
he believes was the first experiment using a
The Chicago group moved rapidly to
bubble chamber. Pless 7, working under
liquid hydrogen, not only helping to show that
Hildebrand with the assistance of Dick Piano,
liquid hydrogen was a useful filling for bubble
exposed a 13 mm x 27 mm x 27 mm glass
chambers
but
also
carried
out
an
W.B. Fowler~American chambers
44
Figure 2. Hildebrands first tracks in glass
Figure 3. First experiment with a Bubble
chamber
Chamber. A proton-proton scattering is seen
1 cm in diameter filled with
isopentane (1954).
in the isopentane liquid using the Chicago Cyclotron.
The stereo photograph was
obtained operating at 460 Mev. (1955).
experiment 8 using an 18.7 MeV negative
use the device for physics. They built a 10-
pion beam at the University of Chicago
cm diameter propane chamber which was
cyclotron,
immediately replaced by a 15-cm diameter propane chamber that was used without
2.2. The Columbia Group In 1954 Jack Steinberger and three
magnetic field at the newly commissioned Brookhaven Cosmotron.
graduate students, J. Leitner, N.P. Samios
A number of results were obtained on the
and M. Schwartz, began to study the bubble
properties of the new unstable (strange)
chamber technique which had just been
particles at an event rate unattainable with
discovered by Glaser. Their interest was to
older techniques. This began a new phase in
WB. Fowler~American chambers
45
high energy physics experimentation where
--the determination of the co and ~ decay
the bubble chamber dominated particle
widths (lifetimes), 1962
physics for the next dozen years.
--the determination of the Z 0 - - A 0 relative
This group published three events of the
parity, 1963
type Z 0 ~ A ° + 7, which proved the existence
--the
of the Z 0 hyperon and gave a measure of its
the
mass. This experiment used a new propane
AS-
chamber, eight times larger in volume, and
1964.
with magnetic field. This chamber also
Two Italian groups, the Bologna group of G.
introduced the use of more than two stereo
Puppi and the Pisa group of M. Conversi,
cameras, a development important for the
participated
rapid, computerized analysis of events.
experiments. The first Columbia hydrogen
Subsequent bubble chambers incorporated at
bubble chamber is shown in Figure 4.
least three views.
demonstration of
the
validity
of
AQ rules in K 0 and in hyperon decays,
in
some
of
the
above
AI Prodell provided data on the 170-liter
For ten years, the Columbia group played
heavy liquid bubble chamber 9 built by the
a major role in bubble chamber construction
Columbia group. The volume occupied by the
and experimentation.
Professors Piano,
liquid is a section of a truncated cone 15 in.
Baltay, Franzini, Colley and Prodell, and a
deep with a 15 in. radius at the back of the
nunber
the
chamber and a 14 in. radius at the single
collaboration. They constructed three more
glass window, which is 4 inches thick. The
bubble chambers: a 12" H2 chamber as well
magnetic field is 15 kG and the magnet was
as 30" propane and H2 chambers, developed
later used with the 30" Columbia-Brookhaven
the analysis techniques, and performed a
hydrogen chamber constructed later. Figure 5
series of experiments to clarify the properties
shows a schematic view of this chamber.
of the
of
new
students
new particles.
joined
Some
important
One final note which I found interesting
experiments of this period are:
concerning the Columbia
--the demonstration of parity violation in A
chamber effort came from Norman Gelfand.
decay, 1957
He pointed out that bubble chamber film
--the demonstration of the 8 decay of the
analysis
pion, 1958
experimenters
--the determination of the ~0 parity on the
individual
basis of angular correlation in the double
Gelfand studied the annihilation of stopped
internal conversion of the gamma rays, 1962
antiprotons in hydrogen. He reported 1° in the
was
divided
group bubble
up
among
and there was a lot of
effort possible.
For instance,
W.B. Fowler~American chambers
46
"4 w 4 v
~
F N ~ 0 ¥4LvE
V4
4NOER
ol
LIGMT 5OunCE
/
CONDENSING L Et~5
dME..R4 EA'$
Figure 4. The first Columbia Hydrogen bubble chamber, 12 inches in diameter in a magnetic field of 13.4 kG.
HEATER
-"-
\"
Physical Review, under his sole name, the
/
X
results of 1193 events accumulated in the Columbia-Brookhaven 30" hydrogen bubble
/
CHAMBE~R
,E::CLE
yOKE
chamber for the purpose of studying i~p annihilation
at
rest
into
~+~-~o. A
considerable contrast to todays lists of hundreds of authors reporting colliding detector results.
2.3. The Adair Group One of the most interesting responses to Figure 5. Schematic view of 170- liter heavy
the request for information about American
liquid bubble chamber assembly built by the
bubble chamber history came from Bob Adair
Columbia group.
~B. Fowler~American chambers
at Yale. Perhaps the best way to present his views is to quote from his letter.
47
"The chamber was relatively unique for that time, in that a piston was used for
"To think now about the old bubble-
expansion. In that early time, I had to invent
chamber days is, for me, a pleasant trip down
my own instrumentation (though that was not
memory lane.
necessarily
different
than what others
invented at the same time.) Hence, I put in a "1 came to BNL in the fall of 1953 with a
capacitative diaphragm to measure the
background in classical nuclear physics. After
pressure change on expansion, a hydrogen
some abortive essays in emulsion with Ed
vapor pressure thermometer to determine the
Salant and with electronics with Dick Madey,
temperature and a resistor chain in the
I got involved with building hydrogen targets
hydrogen reservoir to measure the depth of
with AI Schlafke and learned a little about
hydrogen in the reservoir.
hydrogen. Then I decided to move to
"At the time it first operated, I think that
hydrogen bubble chambers thinking that they
only Louis AIvarez's chamber of roughly the
were so new that, at any rate, I wouldn't be
same size -- and expanded quite differently --
far behind anyone technically.
was running though the tiny chamber that
"Then, some time about the fall of 1954, I
Roger Hildebrand and (Piano and Pless) had
began the design and construction of a small
operated in a measurement of pi-p scattering
hydrogen chamber with a new technician,
was the very first H-chamber.
Rich Larsen, and with Lyle Smith, Lyle was so busy with machine operations, etc. that he
"Late in 1956? Leipuner, Larsen , and I,
wasn't able to spend much time at the project
began to design a larger chamber with a field.
but what time he did spend was valuable.
This was 14" in diameter in a magnet and
Roughly September 1955, larsen and 1
was finished, I would guess, at the end of
finished the chamber and ran it with colbalt
1957 (here my dates are fuzzy). I guess one
60 -- and it worked. (I recount seeing tracks
could better date it by the completion of the
in the chamber as one of mv areatest instant
20". We were a few months ahead -- so that
thrills in physics.)"
for a few months we had the second biggest
Many of us no doubt share in this
hydrogen bubble chamber in the world;
recounting of seeing the first tracks of
second to the Berkeley 15" chamber (which
charged
in bubble chambers.
was, however, somewhat deeper). As I recall,
Continuing with the quote from the Adair
the total capital cost of our chamber and
letter.
magnet was not much more than $50,000.
particles
W.B. Fowler~American chambers
48
"We used this chamber to look at Ko-p
2.4. The MURA-ANL-Fermilab 30"
interactions where we 'discovered' the Yo
Hydrogen Bubble Chamber
(Phys. Rev. Letters 6, 283 (1961). (We were
The project to construct the 30" began
only a little behind Alverez who saw the
with a succession of propane chambers that
charged Y's.) Then, we looked at a large flux
were constructed at Wisconsin beginning in
of K-L's (Phys. Rev. 132, 2285 (1063)), we
1955. These chambers ranged in size from a
examined Ko decays and saw a hint of what
couple of inches in diameter up to a 15 '°
was shown later by Fitch and Cronin to be
diameter propand-freon chamber. In 1958
CP=violation.
Walker and Ballam proposed a 30" heavy
"During this period, others used our
liquid chamber to be used at the cosmotron
chamber also with Rich Larsen running the
but Steinberger won out and constructed the
show. The most important result, was the
30" propane and 30" hydrogen chambers you
discover of the rho-0 by Walker and Erwin but
have already heard about.
others, Leona Marshall and Dave Barge, and Walter Selove, also used the chamber.
hydrogen chamber that discovered the p
"Technically, the chamber had a level of followers
in
chambers
built
by
After working with Adair using the 15"
meson at BNL, Walker turned his attention to
Ned
the 30" which turned out to be one of the
Goldwasser and Lou Koester at Illinois and
most productive chambers used first at the
by Erwin and Walker at Wisconsin. Also, later
Argonne ZGS and later at Fermilab. Walker
Fred Eisler looked at K-decays at the AGS --
reports that from 1964 to the end of the
and found CP violation effects like the kind
running at Argonne there were 64 Phys. Rev.
we saw but he wanted to prove we were
Letters and 114 articles from 16 institutions.
wrong so he never published his results (but we did. Physics Letters 12, 67 (1964). "We never wrote an engineering, or
Of interest is the January 1960 proposal which Walker provided a copy of sets a budget of $370,000 for materials
and
instrumentation, paper on the chamber. With
$188,000 for
a small group (of three, Larsen, Leipuner,
physicists, 2 engineers, 2 draftsmen, 10
and I) we couldn't seem to break away from
machinists and 8 technicians man years.
physics to do the engineering analyses
Figure 6 shows a schematic of the MURA-
desirable for a chamber paper.
ANL-Fermilab 30 inch.
"Anyway, it was great fun while it lasted."
labor,
which
included
4
The excellent picture quality that this chamber was capable of is shown in Figures 7 and 8. Table 3 shows the wide diversity of
H(B. Fowler~American chambers
49
L
ChamberExpansionPistons (3 in line)
MagnetCoil (waterand electrical connections
•
MagnetSteel~ ChamberWindows(34' O.D.)--. CondensingLenses~l~ Liquid NitrogenThermalSt Vacuum Can ' Xenon Fbsh Tubl Housing
")"
Hydrogen Observation Port
~
sCamera Lens and Mirror Housin9
Vacuum Pure
CameraFilm ~zlne I~rtk:~ enter)"
I
;E
Figure 6. Schematic view of the MURA-ANL-Fermilab 30 inch hydrogen bubble chamber.
beams and users of the MURA-ANL-Fermilab
fluid caused problems due to index of
chamber by presenting a list of experiments
refraction variations from temperature non-
and number of pictures taken at Fermilab.
uniformities; however, the chamber turned out to be quite useful. The sensitive volume
2.5 Wilson Powell's 30" Propane Chamber Propane
chambers
were
pursued
was 30.5" x 21.5" x 6.5" with a magnetic field of 14,000 gauss.
because they were faster to build. Powelrs
Powell invented the use of Scotchlite
group built the first large propane chamber by
beads for brightfield chamber illumination,
using hydrostatic support rather than a large
after starting out with a plastic retrodirector.
thick window. The oil used as the support
This scheme worked extremely well and was
7
WB. Fowler~American chambers
50
Figure 7. A 5.5 GeV/c K" beam in MURA-ANL-Fermilab 30" hydrogen chamber taken in 1965 at ANL.
in fact one of the enabling advances in
"The chamber was used early on to
bubble chamber technology that allowed for
produce the E', in a 5 GeV =" beam, one of
the development of the giant chambers to be
the first pictures of that particle. The chamber
described by M. Derrick later in the program.
was used to look at antiprotons, and the
Bob Birge provided a summary of the 30" propane chamber use in experiments.
charge exchange to produce antineutrons. (Figure 9 shows the first example of an antiproton charge exchanging to yield an
51
W.B. Fowler~American chambers
\ higan
Rochester Collaboration~
May, 1973
tG~V3~!it°h Hy~r°~°nn I B n ~ c ~ i ° n b e ~ \ National Accelerator Laboratory
~/
/ /
/
P +
/,
:
=-+ (19 charged particles)
i
L~-+
Ao
I
L_~ p + ~-
I I
...': /
-
..:
" - ~ .... -
,
i
~:.
_
/
=. . ..............................
. . . . .
~
,/ .
/
_ .........
...........-"-: . . . . . . . . . . . . . . . c'-:....~ ............. ,......... ~ , . . ~ - - -
• ...~,-~:.. ~ / .................................................................... ~ ......=..::;.::. ;; " ~ _ ~ . ~ : : . , y . ! : ; 2 . :
•
x = -.38 PT = 0.58 GeV/e
/
~
................ '................. ~<-:
_~ particle
............... ---.~..~.-.:"'7-m _ _ ~
~ ' " - ~ . - .
--
-. . . . . . .
-~ :.-:."
. _,..=.,,=~'--'..".~; ...,:~...C~,~.~:,.:.=.,c._:.-~..-:/~:.::::..._,.~....T
; . . . . .
" .......
: "- .:-:7'.
....
.. . . . . . .
~
~/ -~
............
_ .._-.,:'-
~ .......... ;_,_.-~:~F..-;? ........... :
. ~,. . . . . ~. . . . . . . . . . . . . . . -~..,..,_~---~.---.;;,~__,--:,: ;~:
: ......
"-:""""~" ~ - = " ~ -
.-:--:
" " -: ~-~=-,'~ c-, n ~ ~
:"z~
.... ~--, . . . . . ; .............k ~\................................. ---:U;-}"-<-. L'--'; . . . . . .T-.:::-.:;:-Z. .~ . . . . !. . . . . . . . . . . . . . - __.~.~.-:zT.-~ -.,~.. . . . . . . .. 'X
°
. ~
.....
'
"",~.
-... ...... ;.
Figure 8. A 405 GeV Proton beam at Fermilab showing production of F," taken in May 1973 with MURA-ANL-Fermilab 30" hydrogen chamber.
antineutron which then annihilates in the
Bud Good's original idea, with Piccioni
liquid propane creating multiple tracks, whose
pushing to do the experiment, and was Bob
energy proves that it was an antineutron).
Good's thesis.
Then there were many runs on stopping K +, including experiments on the Ke4 decay, and
"Eventually the chamber was put into a o K" beam and the spin of the Y1 was
K!13, looking for time reversal invariance and
measured along with parameters of the
form factors. The most interesting experiment
Lambda Hyperon."
to me was the run on Regeneration and Mass Difference of Neutral K Mesons, where we installed a 6" thick tungsten block in the chamber to regenerate K~S(o,1), from a beam o of K 2, in a forward diffration peak. This was
2.6. Helium Chambers
Martin Block took on this very difficult technique early on and worked with
52
WB. Fowler~American chambers
Table 3 Thirtv (30~ inch hvdro(]en chamber runs at Fermilab Number
Experiment Number
Beam
Spokesperson
Status
of Pics
2B
Hybrid
Smith
Completed
479 K Pix
37A
P-P @ 300
Malamud
Completed
51 K Pix
121A
PI+ @ P-P @ 100
Lander
Completed
104 K Pix
125
PI--P @ 100
Morrison
Completed
53 K Pix
137
PI--P @ 200
Huson
Completed
48 K Pix
138
P-P @ 400
Vander Velde
Completed
52 K Pix
141A
P-P @ 200
Fields
Completed
67 K Pix
143A
PI--P @ 300
Mulholland
Completed
51 K Pix
154
Hybrid
Pless
Completed
105 K Pix
161
P-P & NE @ 300
Mapp
Completed
51 K Pix
163A
PI--P & NE @ 200
Walker
Completed
52 K Pix
194
P- D @ 100
Murphy
Completed
92 K Pix
196
P - D @ 400
Engelmann
Completed
109 K Pix
209
P- D @ 300
Dao
Completed
106 K Pix
217
PI+ & P-P @ 200
Lander
Completed
85 K Pix
218
PI--D @ 200
Yager
Completed
72 K Pix
228
PI+ & P-P @ 60
Ferbel
Completed
37 K Pix
252
P-P @ 100
Ferbel
Completed
33 x K Pix
280
P- D @ 200
Fields
Completed
103 K Pix
281
Hybrid
Smith
Com ~leted
301 K Pix
295
PI+ & P-D @ 200
Yekutieli
Corn ~leted
156 K Pix
299
Hybrid
Pless
Com ~leted
431 K Pix
311
Pbar-P @ 100
Neale
Com ~leted
98 K Pix
338
PI--D @ 360
Moriyasu
Com ~leted
53 K Pix
344
Pbar-P @ 50
Gutay
Com ~leted
145 K Pix
345
Pbar-D @ 100
Ekspong
Com ~leted
61 K Pix
570
Hybrid
Pless
Com ~leted
1,068 K Pix
597
Hybrid
Whitmore
Com ~leted
658 K Pix
TOTAL
4.688 K Pix
~B. Fowler~American chambers
53
Figure 9. An antiproton enters the bubble chamber from the top. Its track disappears at the arrow as its charge exchanges ~ ~ nn. The antineutron produces the star seen in the lower portion of the picture. The energy released in the star was greater than 1500 MeV.
Fairbanks and Harth and later with Pevsner
sheets of floating glass windows similar to
and Puppi.
superinsulation technology.
Block points out that Fairbanks' cryogenic
One of the interesting occurances was
experience was important in being able to
when they were first set up to run on the
overcome many of the problems. They were
Cosmotron the Cosmotron had a major
the first to use indium gaskets and schlieren
magnet failure and Block contacted Alvarez
photography. They also used multipole
and arranged to transport
the
helium
chamber to Berkeley where they set-up and
W.B. Fowler~American chambers
54
ran using the Bevatron. Block thinks that they
As mentioned before, the Shutt group
were probably the first outside user group at
was the leader in the use of high pressure
LBL. This no doubt lead to their use of 72"
diffusion cloud chambers at the new higher
film for the famous
energy accelerators that came into being
Pevsner-Block
eta
following
experiment. The Northwestern group designed and
World
War
I1. When
Glaser
discovered the bubble chamber, the Shutt
built the 50 cm He chamber 11 first tested in
group
October 1965.
importance of this new technique. Their
There were other helium chamber efforts
at
Brookhaven
recognized
the
interest was in hydrogen and in chambers
in the U.S. and Tom Fields provided an
with
small
bubble
size
and
minimum
example of K" stopping in the 10" ANL\CMU
distortion due to liquid motion or index of
helium chamber taken in 1966. Previously
refraction variations. The 20-inch piston
they had a 6" He chamber that operated for
expanded hydrogen bubble chamber was the
the first time in 1960.
result of considerable effort to accomplish
Also to be noted is that the Carnegie
these objectives, and was brought into use
group built a 6" hydrogen chamber (first
when the Brookhaven Alternating Gradient
physics run 1957) and an 8" propane
Synchrotron first operated. Simultaneous with
chamber (first physics run 1957) used for
the experimental runs using the 20 inch, the
absorption of negative muons in C12 leading
work toward the larger 80 inch was initiated in
to production of bound B12, which required
1959. The 80 inch (Figure 11) consists of a
-20 millisec sensitive time. This same group plus ANL physicists
vessel 80 inches long in the direction of the
made the important step of constructing the
particle path, filled with liquid hydrogen,
first
a
insulated with vacuum and placed in a
superconducting magnet. The 10" ANL\CMU
magnetic field of 20,400 gauss. The 80 inch
superconducting magnet helium chamber
had its first cool-down in May 1963 and the
had a 41 kg field and yielded 18 physics
first tracks were seen on June 2, 1963. The
papers. Figure 10 shows a schematic view of
first experiment was an exposure in a
this chamber in its superconducting coils.
separated 5 GeV K" beam. The start of that
bubble
chamber
that
used
run was December 14, 1963 and after 2.7. The Brookhaven 80 Inch Hydrogen Bubble Chamber
133,000 photos the ~" was discovered late in January 1964. The data on the event made the Physical Review Letters of February 24,
W.B. Fowler~American chambers
1964, and you might hear more of this later from Nick Samios. However, since I am first I
55
4. W.B.Fowler, R.P.Shutt, A.M.Thorndike, 0 and W.L.Whittemore, "Production of V 1
get to show it first, see Figure 12.
Particles
During 11 years of operation, the 80 inch
by
Negative
Pions
in
Hydrogen", Phys. Rev. 91 (1953), 1287.
produced ~12x106 pictures; 27% were
5. W.B.Fowler, R.P.Shutt, A.M.Thorndike,
analyzed by BNL scientist and 73% by
and W.L.Whittemore, "Production of
university users groups. Operation of the 80
Heavy Unstable Particles by 1.37 GeV
inch was terminated in October 1974 due to a
Pions", Phys. Rev. 98 (1995), 121-30.
budget crunch.
6. J.Ballam in Proceedings of the Joint Japanese-U.S. Seminar on Elementary
REFERENCES
Particle Physics with Bubble Chamber
1. From "The God Particle" copyright @ 1993
Detectors, SLAC-144, March 1972, pp
by Leon Lederman and Dick Teresi,
20-1, 20-15.
published by Houghton Mifflin Co., N.Y.,
7.
N.Y.
8. D.E.Nagle,
2. W.B.Fowler, R.P.Shutt, A.M.Thorndike and W.L.Wittemore, "Diffusion Cloud Chambers for Cosmotron Experiments", Rev. Sci. Instrum. 25 (1954), 996-1003. 3. W.B.Fowler, R.P.Shutt, A.M.Thorndike and W.L.Whittemore, "Observation of V0 Particles Produced at the Cosmotron", Phys. Rev. 90 (1953), 1126-7.
I.Pless, Phys. Rev. 104, (1956), 205. R.H.Hildebrand
and
R.J.Plano, CERN Symposium, Vol. 2 (1956). 9. A.Prodell, Rev. Sci. Inst. 33, (1962), 1327. 10. N.Gelfand, Phys.Rev. 169 (1968), 1077. 11. R.Walker, et al., Rev. Sci. Inst. 39 (1968), 1407.
~B. Fowler~American chambers
56
REFLE EX v---4l-
, Q..~
-----i
I0" BUBBLE CHAMBER
:
'
ASS WINDOW
.-,-------CAMERA LIGHT S O U R C E ~
PLASTIC LENS WINDOW
SUPERCONDUCTING MAGNET
~
N
Figure 10. The ANL 10" helium bubble chamber with superconducting coils.
2 SHIELD
~B. Fowler~American chambers
57
Q HYDROGEN CHAMBER Q MAIN WINDOW (~CYLINDER ( ~ PtSTON Q NECK ( ~ VACUUM CHAMBER Q CAMERAS ( ~ LIGHT SOURCE Q REFLECTORS ( ~ MAGNET
: t::i
ii:,
i
q:
Q EXPANSION SYSTEM
(~HIGH VACUUM P U M P S
cl
(~
YOKE
\
•
..__1
!'
r.::L
.1
ii
J ......
w
Figure 11 Schematic view of the Brookhaven 80 inch bubble chamber. The particle beams are / to this view.
58
W.B, Fowler~American chambers
/ j
.-// / /
J
/
~2 (8)
I II ~ o
K°I I
?
(4)
(3) K-
(i)
Figure 12. On the left is the photograph of the event taken in the 80-inch bubble chamber, with its reconstructed drawing on the right where neutral particles are indicated by broken lines. One of several incoming K minus particles from the accelerator beam collided with a proton and created a neutral K zero meson (K°), a K plus meson curving to the left, and an Omega minus (~') that after about 10 1 0 second decays into a Pi minus (~') and a neutral Xi zero (E 0) particle. The ~0 is identified by the disintegration of its neutral decay products; two gamma rays (y and Y2) that give rise to positron-electron pairs, and a Lambda zero (A 0) that yields a ~" and a proton (p). Knowledge of the masses and momenta of the charged decay products of neutral particles that leave no tracks made it possible to identify the third particle emerging from the initial collision as a K °.