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Use of a thermoluminescence sheet for electron beam profile measurement
NUCLEAR
INSTRUMENTS
AND METHODS
I28
(I975) I73-I74; © N O R T H - H O L L A N D
PUBLISHING
CO.
USE OF A THERMOLUMINESCENCE SHEET FOR ELECTRON BEAM PROFILE MEASUREMENT SHIGEYOSHI MIONO
Department of Physics, Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka, Japan Received 1 Juli 1975 Thermoluminescence (TL) sheets were made for observation o f the burst produced by cosmic ray muons. This sheet is also a very useful detector for measuring the electron beam intensity profile.
The field of thermoluminescence dosimetry (TLD) has been developing rapidly during the past ten years. Tin-activated calcium sulphate (CaSO4:Tm) developed by Matsushita Central Research Laboratories 1) (Osaka, Japan) is an excellent phosphor from the point of view of sensitivity, linearity over a wide dose range, fading, stability, etc. A couple of years ago, preliminary experiments using the CaSO4:Tm sheets have been performed to examine the feasibility for observation of the electromagnetic cascade shower produced by cosmic rays. While calibrating luminescence yield versus exposure using an accelerator electron beam, we found the possibility of a very useful detector for measuring the electron beam profile. The advantages of the use of
these sheets for the measurement of electron beam profiles is simple reading and repeated use after annealing. Hitherto, many authors 2~*) devised various methods to measure the electron beam intensity profile. A measurement using TLD (LiF, Harshow Chemical Co.) was reported by Svensson et al.5). However, reading after the exposure is inconvenient and evaluation of the radiation dose is by point-topoint plotting and is not continuous as the present method. The TL sheets were made by mixing CaSO4:Tm powder with poly-imid adhesive (heat-resistive resin) and spreading a uniform layer of 80/tm over a 30/tm aluminium foil of size 10 cm x 100 cm. After readout of these contour lines and development of the X-ray
Fig. 1. Photograph o f the TL sheet (this side) and reading apparatus. The heating device o f hot air jet is removed.
173
174
SHIGEYOSHI
(I) (2) (3) (4) (5) (6)
E~
1009
M1ONO
photo tube IP21 TL sheet
tungsten wire cylindrical mirror cool jet hot jet
1009 *4358
Chart Re¢oder
Fig. 2. A n outline o f an i m p o r t a n t feature o f the apparatus, and block d i a g r a m o f the electronic circuit.
]
10~
103 ~
e~
102 ~
®
10
20 (cm)
10
0
Fig. 3. Electron beam with energy o f 700 MeV; intensity profile. Total n u m b e r o f electrons is 1.45 × 10 l0 particles.
films, we found that the sensitivity of TL sheets is better than Sakura's process and R-R-type films, and nearly equal to that with N-type films. At present, improvement in scanning accuracy is difficult. The main reason is that the hot air jet used for heating can not be made very narrow. If a carbon dioxide (CO2) gas laser, for example, is used for heating, one can do more accurate scanning. We also expect many other applications of
Fi~. 4. The transverse section o f the electron beam. (a) C o n t o u r lines obtained by T L sheet; (b), (c), (d) process, N-type and R-R-type X-ray film, respectively.
TL sheets as detectors, such as measurements of the build-up factor, the three-dimensional spread of electromagnetic cascade showers, etc. The author wishes to thank Dr T. Yamashita, Matsushita Central Research Laboratory, for his very useful help in making TL sheets. I am also thankful to Prof. Y.Murata and staff of the Electron Synchrotron, Dr A. Osawa of the Cosmic Ray Section of the Institute of Nuclear Study, University of Tokyo, for their kind and helpful assistance in this experiment. References 1) T. Y a m a s h i t a , N. N a d a , H. Onishi and S. K i t a m u r a , Proc. 2nd Intern. Conf. on Luminescence dosimetry (1968) p. 4. ~) D. E. Martz and J. D. R o b i n s o n , Rev. Sci. Instr. 34 (1963) 1246. 3) R. W. Dressel, Nucl. Instr. a n d Meth. 28 (1964) 261. 4) S. Okabe, T. T a b a t a a n d K. Tsumori, Jap. Appl. Phys. 5 (1966) 68. 5) G. K. Svensson, R. C. McCall, T. M. Jenkins and W. R. Nelson, Proc. 2nd Intern. Conf. on Luminescence dosin:etry (1968) p. 737.
INSTRUMENTS
AND METHODS
I28
(I975) I73-I74; © N O R T H - H O L L A N D
PUBLISHING
CO.
USE OF A THERMOLUMINESCENCE SHEET FOR ELECTRON BEAM PROFILE MEASUREMENT SHIGEYOSHI MIONO
Department of Physics, Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka, Japan Received 1 Juli 1975 Thermoluminescence (TL) sheets were made for observation o f the burst produced by cosmic ray muons. This sheet is also a very useful detector for measuring the electron beam intensity profile.
The field of thermoluminescence dosimetry (TLD) has been developing rapidly during the past ten years. Tin-activated calcium sulphate (CaSO4:Tm) developed by Matsushita Central Research Laboratories 1) (Osaka, Japan) is an excellent phosphor from the point of view of sensitivity, linearity over a wide dose range, fading, stability, etc. A couple of years ago, preliminary experiments using the CaSO4:Tm sheets have been performed to examine the feasibility for observation of the electromagnetic cascade shower produced by cosmic rays. While calibrating luminescence yield versus exposure using an accelerator electron beam, we found the possibility of a very useful detector for measuring the electron beam profile. The advantages of the use of
these sheets for the measurement of electron beam profiles is simple reading and repeated use after annealing. Hitherto, many authors 2~*) devised various methods to measure the electron beam intensity profile. A measurement using TLD (LiF, Harshow Chemical Co.) was reported by Svensson et al.5). However, reading after the exposure is inconvenient and evaluation of the radiation dose is by point-topoint plotting and is not continuous as the present method. The TL sheets were made by mixing CaSO4:Tm powder with poly-imid adhesive (heat-resistive resin) and spreading a uniform layer of 80/tm over a 30/tm aluminium foil of size 10 cm x 100 cm. After readout of these contour lines and development of the X-ray
Fig. 1. Photograph o f the TL sheet (this side) and reading apparatus. The heating device o f hot air jet is removed.
173
174
SHIGEYOSHI
(I) (2) (3) (4) (5) (6)
E~
1009
M1ONO
photo tube IP21 TL sheet
tungsten wire cylindrical mirror cool jet hot jet
1009 *4358
Chart Re¢oder
Fig. 2. A n outline o f an i m p o r t a n t feature o f the apparatus, and block d i a g r a m o f the electronic circuit.
]
10~
103 ~
e~
102 ~
®
10
20 (cm)
10
0
Fig. 3. Electron beam with energy o f 700 MeV; intensity profile. Total n u m b e r o f electrons is 1.45 × 10 l0 particles.
films, we found that the sensitivity of TL sheets is better than Sakura's process and R-R-type films, and nearly equal to that with N-type films. At present, improvement in scanning accuracy is difficult. The main reason is that the hot air jet used for heating can not be made very narrow. If a carbon dioxide (CO2) gas laser, for example, is used for heating, one can do more accurate scanning. We also expect many other applications of
Fi~. 4. The transverse section o f the electron beam. (a) C o n t o u r lines obtained by T L sheet; (b), (c), (d) process, N-type and R-R-type X-ray film, respectively.
TL sheets as detectors, such as measurements of the build-up factor, the three-dimensional spread of electromagnetic cascade showers, etc. The author wishes to thank Dr T. Yamashita, Matsushita Central Research Laboratory, for his very useful help in making TL sheets. I am also thankful to Prof. Y.Murata and staff of the Electron Synchrotron, Dr A. Osawa of the Cosmic Ray Section of the Institute of Nuclear Study, University of Tokyo, for their kind and helpful assistance in this experiment. References 1) T. Y a m a s h i t a , N. N a d a , H. Onishi and S. K i t a m u r a , Proc. 2nd Intern. Conf. on Luminescence dosimetry (1968) p. 4. ~) D. E. Martz and J. D. R o b i n s o n , Rev. Sci. Instr. 34 (1963) 1246. 3) R. W. Dressel, Nucl. Instr. a n d Meth. 28 (1964) 261. 4) S. Okabe, T. T a b a t a a n d K. Tsumori, Jap. Appl. Phys. 5 (1966) 68. 5) G. K. Svensson, R. C. McCall, T. M. Jenkins and W. R. Nelson, Proc. 2nd Intern. Conf. on Luminescence dosin:etry (1968) p. 737.