- Email: [email protected]
β - threshold values for different glass and plastic track detectors
Nuclear Tracks, Vol. 12, Nos I-6, pp. 337-340, 1986. Int. J. Radiat. Appl. Instrum., Part D Printed in Great Britain.
0191-278x/86 $3.00+.00 Pergamon Journals Ltd.
DETERMINATION OF CHARGE (Z) - AND Z/B - THRESHOLDVALUES FOR DIFFERENT GLASS AND PLASTIC TRACK DETECTORS Hameed Ahmed Khan SSNTD -Laboratory Pakistan I n s t i t u t e of Nuclear Science & Technology (PINSTECH) P.O. N i l o r e , Rawalpindi, Pakistan
ABSTRACT Charge (Z)- and (Z/8)-threshold values of (a) a number of glass track detectors, (b) p l a s t i c track detectors such as CR-39, CN-85, Makrofol E, Lexan, and (c) Muscovite mica have been determined experimentally. The c a l i b r a t e d threshold detectors were used f o r the estimation of charge (Z) l~nd Z/B l ~ l u e s of the reaction products emitted in the i n t e r a c t i o n of 86 MeV/nucleon 0 with Hf targets. KEYWORDS Charge (Z), V e l o c i t y (B), Thresholds, Glass and Plastic Track Detectors. INTRODUCTION The use of SSNTD in the determination of charges of the reaction products has been made f r e q u e n t l y in the past (FLEISCHER et a l . , 1975). However, only two p l a s t i c track detectors (Lexan and Makrofol-E) have been c a l i b r a t e d with s u f f i c i e n t accuracy (FLEISCHER et a l . , 1964,1967,1975). Very l i t t l e work has been carried out in the c a l i b r a t i o n of other types of track detectors. P a r t i c u l a r l y , the recently introduced detector CR-39, having higher s e n s i t i v i t y than other detectors is needed to be c a l i b r a t e d in order to e x p l o i t some of i t s unique c h a r a c t e r i s t i c s . Here, at PINSTECH, we have fabricated and c a l i b r a t e d a number of p l a s t i c and glass track detectors. EXPERIMENTAL DETAILS CR-39 and the glass detectors were exposed to charged p a r t i c l e s , having charges in the range of Z=I2 to Z=92. The energy of the charged p a r t i c l e s was varied from 1MeV/nucleon to 960 MeV/nucleon. The exposed detectors were etched in d i f f e r e n t types of etchants in order to reveal and enlarge the l a t e n t damage t r a i l s . Afterwards, careful scanning was carried out in order to determine the conditions appropriate f o r the production of etchable tracks of the p r o j e c t i l e s having d i f f e r e n t Z-values and v e l o c i t i e s . The conditions were studied in order to determine the Z- and Z/8 threshold values f o r the detectors under study. RESULTS AND DISCUSSION Figure 1 shows the results obtained f o r Phosphate glasses f a b r i c a t e d by us at PINSTECH. The composition of these glasses was varied in order to obtain the most sensitive glasses. We have p l o t t e d the Z-number of the p r o j e c t i l e against i t s v e l o c i t y . The f i l l e d c i r c l e s represent the conditions, which are favourable f or the formation of etchable tracks. The open c i r c l e s represent those combinations of 'Z' and 'B' which are not favourable f o r the formation of etchable l a t e n t damage t r a i l s . The s o l i d l i n e has been drawn to roughly i n d i c a t e the boundary between the favourable and the unfavourable combinations of 'Z' and 'B'. The dotted portion of the l i n e is the e x t r a p o l a t i o n and has been in order to estimate
337
338
HAMEED AHMED KHAN
ENERGY/NUCLEON (MeV / n) 5 10 20 5O
2
;0z
ENERGY/NUCLEON ( MeV / n ) 2 5 10 20 50
• 1
I
• I• • •
I
I •
I
60
/
40
t
-
•
(a)
F-
t)
20 I
•
l
i
I
oe•
•
//
60
o
•
I/
ss /
I
ee
BORATE GLASS
•
Z
o
°
o
o
-oI •
•
o ee
I
I
(b)
/
.-
I
ee
/ /J
•-
on. 60 o. w &o,
PHOSPHATE GLA S S
/
(b)
i 11
I
•
p "
(a)
-
/
Q..
•
/
s /
/ / /
80
i, O
•
.~oo °
,0'
o
•
u
-"
o
o
•
•
•
•
PHOSPHATE GLASS
s/"~
^~
I
/
~,o
.
o•
leoe
!
&0 ~
•l
60
/
/
.~" •
O I
80
s~,
O0
•
10
100
I
//
•
BORATE GLASS
/
UO
s s o
) ~
IE 7"
~o
i
N
o
I
o
o
2~ 7
o
o o •
I •
I
1
/ •
•
.i
40
•
eoeo
•
i
o 000
I
I
I
•
/ s°
ooo
8O
•
o
-~
I
10 I
o
t
p/
s
t
,/
../'(c)
/
1,./
40
/
PHOSPHATE GLASS
/1
/
/
/
.."
(c)
/
BORATE GLASS
20
0
~
o
o
o
I I i I 0.1 •,2 03 0.4 05 MAXIMUM VELOCITY OF THE PROJECTILE= ~ (v/c)
Fig. 1 Combinations of Z-, and Z/B-values of ac - - ~ d p a r t i c l e s which are "favourable" and unfavourable" f o r track formation in a phosphate glass.
1~,, 0
I 0.1
i 0.2
I 0.3
I 0.4
MAXIMUM VELOCITY OF THE PROJECTILE:I'} (v/c)
Fig. 2 "Favourable" and "unfavourable" con--6-n-dTtions f o r track formation in a borate glass.
the favourable and unfavourable combinations of the above mentioned two parameters. Section 'a' & 'b' of the above f i g u r e i n d i c a t e near-optimum-compositions of the phosphate glass track detectors, while the section 'c' of the f i g u r e gives the r e s ult s obtained f o r the glass detectors having the optimum composition. I t is quite i n t e r e s t i n g to know t h a t the detector is capable of r e g i s t e r i n g uranium ions having a value of about 0.5. Figures 2 and 3 are the r e s u l t s obtained f o r a Borate Glass and a Lead Phosphate Glass, r e s p e c t i v e l y . Various sections of these two fi g u r e s are as f o l l o w s : Section 'a' & 'b' represent the r e s u l t obtained by using near optimum compositions of the above mentioned two glasses, section 'c' indicates the r e s u l t s obtained by using the optimum composition of these two glass track detectors.
CHARGE
(Z) - A N D
Z/B
- THRESHOLD
VALUES
339
I t i s quite apparent from the comparison of figures 1 to 3 that Phosphate Glass is the most s e n s i t i v e glass track detector, while Lead Phosphate Glass is the least sensitive track detector among the glasses fabricated and calibrated by us. Figure 4 gives the results obtained f o r d i f f e r e n t combinations of Z and of the p r o j e c t i l e f o r a few commonly available p l a s t i c and glass track detectors. Some r e s u l t s f o r Muscovite track detectors have also been included in Fig. 4. I t i s quite apparent from the f i g u r e that the CR-39 p l a s t i c track detector fabricated by the Homalite Corporation is the most sensitive track detector available at present (and investigated by us). The CR-39 track detector fabricated by us has a response which i s very s i m i l a r to that of the CR-39 fabricated by the Homalite Corporation. I t i s very encouraging to note that CR-39 track detectors are capable of r e g i s t e r i n g tracks f o r carbon ions having r e l a t i v i s t i c energies. The above described c a l i b r a t i o n of various track detectors was used to estimate the ENERGY/NUCLEON ( M e V / n ) charge Z and Z/B values of the reaction products e m i t t ~ in th~8ointeraction of 2 5 10 2O 10 86 MeV/nucleon 0 with Hf. The results • 1 • I 6moo ~ / / have been summarized in Table I . These 80 / , (a) results were used to determine the r e l a t i v e 6o /,/ contribution of the peripheral-, and • • • / c e n t r a l - c o l l i s i o n s in the above mentioned s/ reaction. 40 LEAD PHOSPHATE GLASS
ENERGY/NUCLEON (MeV/n) 20
O52 5 10 20 o
0 0
w .J
~-
10I
~
0
Q:
Iw
0
0
0
•
--
4C
--
•
100
i
I
*LEAD- PI~SPHATE -- GLASS
0
I
Do~
-
60
t
200 300 I
I
0 0
,,, • ; Q
~.
U
0 0
f I I
o
50
•
/
~
/
l
(b] Q. F0t. - E
LEAD PHOSPHATE GLASS
I--
i,o'
o nr m
1000 2000
I I I * SSNTI:)$ FABREATED BY U5
/ l
/
/
*PHOSPHATE GLASS
500
o ( HOMAUTE)
Z -
-
o
o
t
o
•
o
°
°oH
i 1
80
s
.." (c)
60
•
•
/j I
•
40
I"
0 0
0
LEAD PHOSPHATE GLASS
01
1(~ O
O.1
MAXIMUM
VELOCITY
0
0
0
0
I
0.2 OF THE
0,2
,, 03
0,~
05
I 06
I 07
] 08
I 09
10
MAXIMUM VELOCITY OF THE PROJECTILE = i3 ( v / c )
Fig. 4 Set of curves showing the "favoura-~-T-6~--and "unfavourable" combinations of "Z" and "ZIB" of different charged p a r t i c l e s in a v a r i e t y of track detectors.
o ) 0 30
i 01
0.3 PROJECTILE:i3(v/c)
Fig. 3 "Favourable" and "unfavourable" con--6-n-dTtions f o r track formations in a lead phosphate glass.
340
HAMEED AHMED KHAN
Table 1 Charge (Z) 1 (Protons) 2 (Alpha P a r t i c l e s ) 8>Z>2 16>Z~8 Z~I6
Z/B-Range ~60 ~164 ~204 ~230
~400
Abundance (%) 32.4 28.7 26.9 10.3 1.7
ACKNOWLEDGEMENT This work has been carried out in the framework of the German-Pakistan agreement on s c i e n t i f i c and technological cooperation. We thank the I n t e r n a t i o n a l O f f i c e , KfK, Karlsruhe, f o r providing support f o r t h i s research. The author is g r a t e f u l to the Alexander von Humboldt (AVH) S t i f t u n g f o r the f i n a n c i a l support and f o r the valuable equipment k i n d l y given to the SSNTD Laboratory (PINSTECH), Pakistan. I am g r a t e f u l to Mrs I. Kenter f o r valuable help in the preparation of t h i s paper. REFERENCES Fleischer, Fleischer, Fleischer, California
R.L., P.B. Price, R.M. Walker, E. Hubbard (1964). Phys. Rev. A133, 1443 R.L., P.B. Price, R.M. Walker, E. Hubbard (1967). Phys. Rev. 156, 353 R.L., P.B. Price, R.M. Walker (1975). Nuclear Tracks in Solids ( U n i v e r s i t y of Press), Berkeley.
0191-278x/86 $3.00+.00 Pergamon Journals Ltd.
DETERMINATION OF CHARGE (Z) - AND Z/B - THRESHOLDVALUES FOR DIFFERENT GLASS AND PLASTIC TRACK DETECTORS Hameed Ahmed Khan SSNTD -Laboratory Pakistan I n s t i t u t e of Nuclear Science & Technology (PINSTECH) P.O. N i l o r e , Rawalpindi, Pakistan
ABSTRACT Charge (Z)- and (Z/8)-threshold values of (a) a number of glass track detectors, (b) p l a s t i c track detectors such as CR-39, CN-85, Makrofol E, Lexan, and (c) Muscovite mica have been determined experimentally. The c a l i b r a t e d threshold detectors were used f o r the estimation of charge (Z) l~nd Z/B l ~ l u e s of the reaction products emitted in the i n t e r a c t i o n of 86 MeV/nucleon 0 with Hf targets. KEYWORDS Charge (Z), V e l o c i t y (B), Thresholds, Glass and Plastic Track Detectors. INTRODUCTION The use of SSNTD in the determination of charges of the reaction products has been made f r e q u e n t l y in the past (FLEISCHER et a l . , 1975). However, only two p l a s t i c track detectors (Lexan and Makrofol-E) have been c a l i b r a t e d with s u f f i c i e n t accuracy (FLEISCHER et a l . , 1964,1967,1975). Very l i t t l e work has been carried out in the c a l i b r a t i o n of other types of track detectors. P a r t i c u l a r l y , the recently introduced detector CR-39, having higher s e n s i t i v i t y than other detectors is needed to be c a l i b r a t e d in order to e x p l o i t some of i t s unique c h a r a c t e r i s t i c s . Here, at PINSTECH, we have fabricated and c a l i b r a t e d a number of p l a s t i c and glass track detectors. EXPERIMENTAL DETAILS CR-39 and the glass detectors were exposed to charged p a r t i c l e s , having charges in the range of Z=I2 to Z=92. The energy of the charged p a r t i c l e s was varied from 1MeV/nucleon to 960 MeV/nucleon. The exposed detectors were etched in d i f f e r e n t types of etchants in order to reveal and enlarge the l a t e n t damage t r a i l s . Afterwards, careful scanning was carried out in order to determine the conditions appropriate f o r the production of etchable tracks of the p r o j e c t i l e s having d i f f e r e n t Z-values and v e l o c i t i e s . The conditions were studied in order to determine the Z- and Z/8 threshold values f o r the detectors under study. RESULTS AND DISCUSSION Figure 1 shows the results obtained f o r Phosphate glasses f a b r i c a t e d by us at PINSTECH. The composition of these glasses was varied in order to obtain the most sensitive glasses. We have p l o t t e d the Z-number of the p r o j e c t i l e against i t s v e l o c i t y . The f i l l e d c i r c l e s represent the conditions, which are favourable f or the formation of etchable tracks. The open c i r c l e s represent those combinations of 'Z' and 'B' which are not favourable f o r the formation of etchable l a t e n t damage t r a i l s . The s o l i d l i n e has been drawn to roughly i n d i c a t e the boundary between the favourable and the unfavourable combinations of 'Z' and 'B'. The dotted portion of the l i n e is the e x t r a p o l a t i o n and has been in order to estimate
337
338
HAMEED AHMED KHAN
ENERGY/NUCLEON (MeV / n) 5 10 20 5O
2
;0z
ENERGY/NUCLEON ( MeV / n ) 2 5 10 20 50
• 1
I
• I• • •
I
I •
I
60
/
40
t
-
•
(a)
F-
t)
20 I
•
l
i
I
oe•
•
//
60
o
•
I/
ss /
I
ee
BORATE GLASS
•
Z
o
°
o
o
-oI •
•
o ee
I
I
(b)
/
.-
I
ee
/ /J
•-
on. 60 o. w &o,
PHOSPHATE GLA S S
/
(b)
i 11
I
•
p "
(a)
-
/
Q..
•
/
s /
/ / /
80
i, O
•
.~oo °
,0'
o
•
u
-"
o
o
•
•
•
•
PHOSPHATE GLASS
s/"~
^~
I
/
~,o
.
o•
leoe
!
&0 ~
•l
60
/
/
.~" •
O I
80
s~,
O0
•
10
100
I
//
•
BORATE GLASS
/
UO
s s o
) ~
IE 7"
~o
i
N
o
I
o
o
2~ 7
o
o o •
I •
I
1
/ •
•
.i
40
•
eoeo
•
i
o 000
I
I
I
•
/ s°
ooo
8O
•
o
-~
I
10 I
o
t
p/
s
t
,/
../'(c)
/
1,./
40
/
PHOSPHATE GLASS
/1
/
/
/
.."
(c)
/
BORATE GLASS
20
0
~
o
o
o
I I i I 0.1 •,2 03 0.4 05 MAXIMUM VELOCITY OF THE PROJECTILE= ~ (v/c)
Fig. 1 Combinations of Z-, and Z/B-values of ac - - ~ d p a r t i c l e s which are "favourable" and unfavourable" f o r track formation in a phosphate glass.
1~,, 0
I 0.1
i 0.2
I 0.3
I 0.4
MAXIMUM VELOCITY OF THE PROJECTILE:I'} (v/c)
Fig. 2 "Favourable" and "unfavourable" con--6-n-dTtions f o r track formation in a borate glass.
the favourable and unfavourable combinations of the above mentioned two parameters. Section 'a' & 'b' of the above f i g u r e i n d i c a t e near-optimum-compositions of the phosphate glass track detectors, while the section 'c' of the f i g u r e gives the r e s ult s obtained f o r the glass detectors having the optimum composition. I t is quite i n t e r e s t i n g to know t h a t the detector is capable of r e g i s t e r i n g uranium ions having a value of about 0.5. Figures 2 and 3 are the r e s u l t s obtained f o r a Borate Glass and a Lead Phosphate Glass, r e s p e c t i v e l y . Various sections of these two fi g u r e s are as f o l l o w s : Section 'a' & 'b' represent the r e s u l t obtained by using near optimum compositions of the above mentioned two glasses, section 'c' indicates the r e s u l t s obtained by using the optimum composition of these two glass track detectors.
CHARGE
(Z) - A N D
Z/B
- THRESHOLD
VALUES
339
I t i s quite apparent from the comparison of figures 1 to 3 that Phosphate Glass is the most s e n s i t i v e glass track detector, while Lead Phosphate Glass is the least sensitive track detector among the glasses fabricated and calibrated by us. Figure 4 gives the results obtained f o r d i f f e r e n t combinations of Z and of the p r o j e c t i l e f o r a few commonly available p l a s t i c and glass track detectors. Some r e s u l t s f o r Muscovite track detectors have also been included in Fig. 4. I t i s quite apparent from the f i g u r e that the CR-39 p l a s t i c track detector fabricated by the Homalite Corporation is the most sensitive track detector available at present (and investigated by us). The CR-39 track detector fabricated by us has a response which i s very s i m i l a r to that of the CR-39 fabricated by the Homalite Corporation. I t i s very encouraging to note that CR-39 track detectors are capable of r e g i s t e r i n g tracks f o r carbon ions having r e l a t i v i s t i c energies. The above described c a l i b r a t i o n of various track detectors was used to estimate the ENERGY/NUCLEON ( M e V / n ) charge Z and Z/B values of the reaction products e m i t t ~ in th~8ointeraction of 2 5 10 2O 10 86 MeV/nucleon 0 with Hf. The results • 1 • I 6moo ~ / / have been summarized in Table I . These 80 / , (a) results were used to determine the r e l a t i v e 6o /,/ contribution of the peripheral-, and • • • / c e n t r a l - c o l l i s i o n s in the above mentioned s/ reaction. 40 LEAD PHOSPHATE GLASS
ENERGY/NUCLEON (MeV/n) 20
O52 5 10 20 o
0 0
w .J
~-
10I
~
0
Q:
Iw
0
0
0
•
--
4C
--
•
100
i
I
*LEAD- PI~SPHATE -- GLASS
0
I
Do~
-
60
t
200 300 I
I
0 0
,,, • ; Q
~.
U
0 0
f I I
o
50
•
/
~
/
l
(b] Q. F0t. - E
LEAD PHOSPHATE GLASS
I--
i,o'
o nr m
1000 2000
I I I * SSNTI:)$ FABREATED BY U5
/ l
/
/
*PHOSPHATE GLASS
500
o ( HOMAUTE)
Z -
-
o
o
t
o
•
o
°
°oH
i 1
80
s
.." (c)
60
•
•
/j I
•
40
I"
0 0
0
LEAD PHOSPHATE GLASS
01
1(~ O
O.1
MAXIMUM
VELOCITY
0
0
0
0
I
0.2 OF THE
0,2
,, 03
0,~
05
I 06
I 07
] 08
I 09
10
MAXIMUM VELOCITY OF THE PROJECTILE = i3 ( v / c )
Fig. 4 Set of curves showing the "favoura-~-T-6~--and "unfavourable" combinations of "Z" and "ZIB" of different charged p a r t i c l e s in a v a r i e t y of track detectors.
o ) 0 30
i 01
0.3 PROJECTILE:i3(v/c)
Fig. 3 "Favourable" and "unfavourable" con--6-n-dTtions f o r track formations in a lead phosphate glass.
340
HAMEED AHMED KHAN
Table 1 Charge (Z) 1 (Protons) 2 (Alpha P a r t i c l e s ) 8>Z>2 16>Z~8 Z~I6
Z/B-Range ~60 ~164 ~204 ~230
~400
Abundance (%) 32.4 28.7 26.9 10.3 1.7
ACKNOWLEDGEMENT This work has been carried out in the framework of the German-Pakistan agreement on s c i e n t i f i c and technological cooperation. We thank the I n t e r n a t i o n a l O f f i c e , KfK, Karlsruhe, f o r providing support f o r t h i s research. The author is g r a t e f u l to the Alexander von Humboldt (AVH) S t i f t u n g f o r the f i n a n c i a l support and f o r the valuable equipment k i n d l y given to the SSNTD Laboratory (PINSTECH), Pakistan. I am g r a t e f u l to Mrs I. Kenter f o r valuable help in the preparation of t h i s paper. REFERENCES Fleischer, Fleischer, Fleischer, California
R.L., P.B. Price, R.M. Walker, E. Hubbard (1964). Phys. Rev. A133, 1443 R.L., P.B. Price, R.M. Walker, E. Hubbard (1967). Phys. Rev. 156, 353 R.L., P.B. Price, R.M. Walker (1975). Nuclear Tracks in Solids ( U n i v e r s i t y of Press), Berkeley.