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Electromagnetic acceleration of particles to cosmic ray energies
NOTES
FROM
ELECTROMAGNETIC
THE BARTOL
ACCELERATION
RESEARCH
FOUNDATION
OF PARTICLES TO COSMIC RAY ENERGIES* BY
W. F. G. SWANN
It has been demonstrated that if a particle is accelerated in an electromagnetic field between two points designated by subscripts (1) and (2), the particle will gain energy in passing from (1) to (2) provided that the quantity J defined by us,)2
J=,+lJsr
-
2%
j- S $
dt
is positive,where dS is an element of path, Us1 and Us2 are the initial and final values of the vector potential along the path, and t is the time. Moreover, if the particle at rest at the point (l), its energy IV2 at the point (2) is such that WZ > e I (1Us2
-
Ud
I
where e is the charge on the particle. The foregoing theorem has been applied to the case where the motivating agency responsible for the electromagnetic field is a toroid with currents circulating in such fashion as they would circulate if the anchor ring of the toroid were wound with a wire in which a current decayed with time. The particular case studied is that where a particle moves along the axis of symmetry, and dimensions are chosen of astronomical size such as to make them apply to such phenomena as are observed in the Crab Nebula. The magnitudes chosen are as follows: a = Radius of cross section of the toroidal winding = 1 light year
~0 = Mean radius of toroid = 2000 light years Ho = Initial field in the toroid = 10e3 gauss v/a = Time for the current to decay to l/e of its initial value = 1000 years. With the above assumptions, a particle of electronic charge, starting from the center of the toroid and travelling along the axis of symmetry would acquire an energy in excess of 3 x lOr*electron volts. * Supported Atomic
Energy
in part by the joint Commission.
program
of the Office of Naval
Research
and the U. S. WI
666
BARTOL RESEARCH
FOUNDATION
[J. I;. I.
NOTES
THE RADIATIONS OF Sn”26AND Bra2* BY
V. S. DUBEY,’ C. E. MANDEVILLE AND M. A. ROTHMAN
Employing coincident scintillation counters of Nal (Tl) and anthracene, beta-gamma and gamma-gamma coincidence studies have been carried out to determine the decay schemes of SrP5 and BP. Gamma rays have been detected with quantum energies of 1960, 1410, 1070, 900, 810, 470, 340, and 230 kev in the disintegration of Snlz5, and with energies 250, 350, 560, 610, 690, 770, 820, 1030, 1290, 1450, 1800, and 2050 kev in the decay of Br82. The energy levels located by the combined energy and coincidence data are, for Sb125: 1070, 1410, 1880, 1970, and 2110 kev; for Krs2:
770, 1450, 1800, 2060, and 2620 kev.
These results can be interpreted on the basis of the single particle model to determine likely spin values for the nuclear states. *Assisted by the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. 1 On leave of absence from Agra College, Agra, India. THE RADIOACTIVITY OF VICTORIAN GLASS BY
C. E. MANDEVILLE
It is well known that during the last century, uranium was often In particular, sodium employed to provide coloration for glass objects. diuranate was added to both flint and soda lime glass to produce a yellow or yellow-green hue (Vaseline glass). Measurements with a scintillation counter show that uranium compounds were introduced into “apple green” and “green” glasses as well, In a geometry providing a relatively poor solid angle, the following gamma-ray counting rates have been observed. Object
Vaseline Glass Vase Apple Green Candle Holder Green Candle Holder
Weight, grams
Counts/min
200
2,500
230 210
2,100
800
Samples of these three types of colored glass are also noted to fluoresce vigorously under black light, emitting the characterist ic green radiation of the UO2++ coordination group which is in soluticn in the glass. Whether or not these properties will be useful in distinguishing in the future between antique items and recently made reproductions will be determined by the legal circumstances throughout the world which may surround the continued use of uranium in glass products.
June,
1956.1
BARTOL
RESEARCH
RADIATIONS
FOUNDATION
FROM
E+
NOTES
667
AND Smn3*t
BY V. S. DUBEY,r C. E. MANDEVILLE
AND M. A. ROTHMAN
spectrometers employing single Using coincident scintillation channel analysis as well as a slow-fast circuit incorporating a 20-channel analyzer, the radiations of Eu’~~ and Sm153 have been investigated. Eu155 is found to decay with emission of two beta spectra having end points of 240 kev (21 per cent) and 150 kev (79 per cent). A gamma ray was detected at 102 kev. An 84 kev-18 kev cascade is also present. The harder beta spectrum is non-coincident with gamma radiation. All beta-gamma coincidences observable at beta-ray energies greater than 150 kev are attributed to the presence of Eu152,‘54. The beta spectra of Sm153are found to have end point energies of 825, 720, 645, and 130 kev and relative intensities of 27, 32, 40, and -0.06. The gamma rays of Sm 153have quantum energies of 70, 100, 170, 530, and 600 kev. The relative intensities of the transitions associated with these gamma rays are, when corrections are introduced to take into account internal conversion, 0.68, 1.0, 4.5 X 10-j, 6.5 X lP, and 1.5 x 10-4. *Assistedby the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. LOn leave of absence from Agra College, rZgra U.P., India. NUCLEAR
RESONANCE
C. P. SWANN
FLUORESCENCE
IN 0’6 *t
AND F. R. METZGER
Using the Bartol-ONR Van de Graaff generator and the reaction’ F1g(p,a)016 as the gamma-ray source, nuclear resonance fluorescence in 016 has been observed. A thick target of CaFt was bombarded with 2pa of 3 Mev protons to give a source strength of about log gamma rays per second. A ring geometry similar to the one employed in previous resonance fluorescence experiments1 was used. Water and benzene scatterers were compared and the difference in the counting rates was attributed to resonance fluorescence in oxygen. Great care was taken to eliminate all neutrons since their presence tended to conceal the effect. Of the first four levels in 016 only the 6.91 Mev and 7.12 Mev states can be responsible for the resonance effect. The angular distributuon of the resonance radiation shows indeed that both of these *Assistedby the joint program of the Office of Naval Research and the 11. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. r See for example, FRANZ R. METZGER, Phys. Rev., Vol. 101, p. 286 (1956).
668
BARTOL
RESEARCH
FOUNDATION
NOTES
[J. F. I.
The reduction of the resonance effect by means of levels participate. a water absorber placed between the gamma-ray source and the scatterer indicates that the lifetimes of these two levels are the same to within a factor of three. Preliminary measurements give lifetimes between lo-l4 and lo-l5 seconds. RADIATIONS
FROM
AU’= *t
BY
V. R. POTNIS
The radiations from Aulg5 have been examined previously in magnetic spectrometers and coincident Geiger Counter arrangements. Two gamma rays with energies about 31 and 99 kev were found to be in cascade in all these studies. The data concerning the presence of the 130 kev cross-over transition of the 31-99 kev cascade have been inconclusive. In order to find some definite evidence of the presence of the 130 kev gamma ray, the radiations from Aulg5 were examined with the scintillation spectrometer of NaI(T1). The presence of 31, 99, and 130 kev gamma rays is seen in the pulse height distribution of the gamma rays. Absorption experiments on each gamma ray were carried out. It has been shown that the 130 kev gamma ray is not due to the simultaneous detection of the two lower energy gamma rays in cascade. *Assisted by the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. 1 Permanent address, Gwalior (M.B.) India.
FROM
ELECTROMAGNETIC
THE BARTOL
ACCELERATION
RESEARCH
FOUNDATION
OF PARTICLES TO COSMIC RAY ENERGIES* BY
W. F. G. SWANN
It has been demonstrated that if a particle is accelerated in an electromagnetic field between two points designated by subscripts (1) and (2), the particle will gain energy in passing from (1) to (2) provided that the quantity J defined by us,)2
J=,+lJsr
-
2%
j- S $
dt
is positive,where dS is an element of path, Us1 and Us2 are the initial and final values of the vector potential along the path, and t is the time. Moreover, if the particle at rest at the point (l), its energy IV2 at the point (2) is such that WZ > e I (1Us2
-
Ud
I
where e is the charge on the particle. The foregoing theorem has been applied to the case where the motivating agency responsible for the electromagnetic field is a toroid with currents circulating in such fashion as they would circulate if the anchor ring of the toroid were wound with a wire in which a current decayed with time. The particular case studied is that where a particle moves along the axis of symmetry, and dimensions are chosen of astronomical size such as to make them apply to such phenomena as are observed in the Crab Nebula. The magnitudes chosen are as follows: a = Radius of cross section of the toroidal winding = 1 light year
~0 = Mean radius of toroid = 2000 light years Ho = Initial field in the toroid = 10e3 gauss v/a = Time for the current to decay to l/e of its initial value = 1000 years. With the above assumptions, a particle of electronic charge, starting from the center of the toroid and travelling along the axis of symmetry would acquire an energy in excess of 3 x lOr*electron volts. * Supported Atomic
Energy
in part by the joint Commission.
program
of the Office of Naval
Research
and the U. S. WI
666
BARTOL RESEARCH
FOUNDATION
[J. I;. I.
NOTES
THE RADIATIONS OF Sn”26AND Bra2* BY
V. S. DUBEY,’ C. E. MANDEVILLE AND M. A. ROTHMAN
Employing coincident scintillation counters of Nal (Tl) and anthracene, beta-gamma and gamma-gamma coincidence studies have been carried out to determine the decay schemes of SrP5 and BP. Gamma rays have been detected with quantum energies of 1960, 1410, 1070, 900, 810, 470, 340, and 230 kev in the disintegration of Snlz5, and with energies 250, 350, 560, 610, 690, 770, 820, 1030, 1290, 1450, 1800, and 2050 kev in the decay of Br82. The energy levels located by the combined energy and coincidence data are, for Sb125: 1070, 1410, 1880, 1970, and 2110 kev; for Krs2:
770, 1450, 1800, 2060, and 2620 kev.
These results can be interpreted on the basis of the single particle model to determine likely spin values for the nuclear states. *Assisted by the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. 1 On leave of absence from Agra College, Agra, India. THE RADIOACTIVITY OF VICTORIAN GLASS BY
C. E. MANDEVILLE
It is well known that during the last century, uranium was often In particular, sodium employed to provide coloration for glass objects. diuranate was added to both flint and soda lime glass to produce a yellow or yellow-green hue (Vaseline glass). Measurements with a scintillation counter show that uranium compounds were introduced into “apple green” and “green” glasses as well, In a geometry providing a relatively poor solid angle, the following gamma-ray counting rates have been observed. Object
Vaseline Glass Vase Apple Green Candle Holder Green Candle Holder
Weight, grams
Counts/min
200
2,500
230 210
2,100
800
Samples of these three types of colored glass are also noted to fluoresce vigorously under black light, emitting the characterist ic green radiation of the UO2++ coordination group which is in soluticn in the glass. Whether or not these properties will be useful in distinguishing in the future between antique items and recently made reproductions will be determined by the legal circumstances throughout the world which may surround the continued use of uranium in glass products.
June,
1956.1
BARTOL
RESEARCH
RADIATIONS
FOUNDATION
FROM
E+
NOTES
667
AND Smn3*t
BY V. S. DUBEY,r C. E. MANDEVILLE
AND M. A. ROTHMAN
spectrometers employing single Using coincident scintillation channel analysis as well as a slow-fast circuit incorporating a 20-channel analyzer, the radiations of Eu’~~ and Sm153 have been investigated. Eu155 is found to decay with emission of two beta spectra having end points of 240 kev (21 per cent) and 150 kev (79 per cent). A gamma ray was detected at 102 kev. An 84 kev-18 kev cascade is also present. The harder beta spectrum is non-coincident with gamma radiation. All beta-gamma coincidences observable at beta-ray energies greater than 150 kev are attributed to the presence of Eu152,‘54. The beta spectra of Sm153are found to have end point energies of 825, 720, 645, and 130 kev and relative intensities of 27, 32, 40, and -0.06. The gamma rays of Sm 153have quantum energies of 70, 100, 170, 530, and 600 kev. The relative intensities of the transitions associated with these gamma rays are, when corrections are introduced to take into account internal conversion, 0.68, 1.0, 4.5 X 10-j, 6.5 X lP, and 1.5 x 10-4. *Assistedby the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. LOn leave of absence from Agra College, rZgra U.P., India. NUCLEAR
RESONANCE
C. P. SWANN
FLUORESCENCE
IN 0’6 *t
AND F. R. METZGER
Using the Bartol-ONR Van de Graaff generator and the reaction’ F1g(p,a)016 as the gamma-ray source, nuclear resonance fluorescence in 016 has been observed. A thick target of CaFt was bombarded with 2pa of 3 Mev protons to give a source strength of about log gamma rays per second. A ring geometry similar to the one employed in previous resonance fluorescence experiments1 was used. Water and benzene scatterers were compared and the difference in the counting rates was attributed to resonance fluorescence in oxygen. Great care was taken to eliminate all neutrons since their presence tended to conceal the effect. Of the first four levels in 016 only the 6.91 Mev and 7.12 Mev states can be responsible for the resonance effect. The angular distributuon of the resonance radiation shows indeed that both of these *Assistedby the joint program of the Office of Naval Research and the 11. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. r See for example, FRANZ R. METZGER, Phys. Rev., Vol. 101, p. 286 (1956).
668
BARTOL
RESEARCH
FOUNDATION
NOTES
[J. F. I.
The reduction of the resonance effect by means of levels participate. a water absorber placed between the gamma-ray source and the scatterer indicates that the lifetimes of these two levels are the same to within a factor of three. Preliminary measurements give lifetimes between lo-l4 and lo-l5 seconds. RADIATIONS
FROM
AU’= *t
BY
V. R. POTNIS
The radiations from Aulg5 have been examined previously in magnetic spectrometers and coincident Geiger Counter arrangements. Two gamma rays with energies about 31 and 99 kev were found to be in cascade in all these studies. The data concerning the presence of the 130 kev cross-over transition of the 31-99 kev cascade have been inconclusive. In order to find some definite evidence of the presence of the 130 kev gamma ray, the radiations from Aulg5 were examined with the scintillation spectrometer of NaI(T1). The presence of 31, 99, and 130 kev gamma rays is seen in the pulse height distribution of the gamma rays. Absorption experiments on each gamma ray were carried out. It has been shown that the 130 kev gamma ray is not due to the simultaneous detection of the two lower energy gamma rays in cascade. *Assisted by the joint program of the Office of Naval Research and the U. S. Atomic Energy Commission. t Presented at the Washington Meeting of The American Physical Society, April 26-28, 1956. 1 Permanent address, Gwalior (M.B.) India.