Proceedings of the 2nd Annual Meeting of Particle Accelerator Society of Japanand the 30th Linear Accelerator Meeting in Japan (July 20 - 22, 2005, Tosu Japan)

EXPERIMENTAL STUDY OF POSITRON PRODUCTION FROM SILICON
AT HIGH BUNCH CHARGES,A)

A)

A)

A)

A)

Tsuyoshi Suwada1 , Kazuro Furukawa , Takuya Kamitani , Masanori Satoh , Takashi Sugimura ,B)
C)
D)
D)
E)
Hideki Okuno , Kensei Umemori , Hiroyuki Fujimoto , Ryosuke Hamatsu , Katsuhide Yoshida ,F)
F)
G)
Alexander P.Potylitsyn , Igor S.Tropin , Robert Chehab ,A) Accelerator Laboratory, High Energy Accelerator Research Organization (KEK),B) Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK),C) Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK),
1-1 Oho, Tsukuba, Ibaraki 305-0801, JapanD) Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397, JapanE) Saga Light Source, 8-7 Yayoigaoka, Tosu, Saga, 841-0005, JapanF) Nuclear Physics Institute, Tomsk Polytechnic University, 634050, P.O.Box 25, Tomsk, Russia
G)
LAL, IN2P3-CNRS, Universite de Paris-Sud, Bat.200-B.P.34, 91898 Orsay, FranceAbstract
We investigated so-called channeling breaking phenomena through positron production from an axially-oriented
silicon crystal with the thickness of 2.55 mm using 8-GeV channeling electrons with high bunch charges at the KEKB
electron/positron injector linac. The crystal axis <110> has been aligned to the electron beam by a precise goniometer.
The positron yield generated in the forward direction with the momentum of 20 MeV/c was measured by using amagnetic spectrometer depending on the electron bunch charge. The results show that the positron yield is proportional
to the impinging bunch charge in the intensity range of 0.1-3.2 nC within the experimental errors.

高電磁場が及ぼすシリコン結晶による陽電子生成実験
 µ) zN]FøO^TAY@]Ö
²'àÓ$(öøÉ£+(ù'! "(ûÖ·8.$/0(# 5  p8c $5qû?Z^Q) »bf(YL:@X;E^1ýP9>JY^'¼65öø8 ¦"zÖ²8ºÍ$öøÉ£û8Ø" 5 6) ü<MZ=^ø8D]?BI]&%(ðòºÍ'Áöø8É£5$ ¶(¯¾#) ºÍ(ÂçÞ'25«n(/öøÉ£ñ'õËÉ
53# 5 Ö²ºÍ'25öøÉ£(t )ü<MZ=^øÖ²'½ "p$ø) Ö²{s(j5øÐRI]AVZ'¨Å6 {s$(÷Í& djÊ8ê"FVMY]?¬CR1À¢uy¬CB8xÆÍ'É£5$' 5 63(¬) øöøÉ£ïÒ'5öø(É£xÆ85$´#5 ¤ ) ðòÖ²ºÍD]?BI]1oÕÖ²ºÍAY@] E;WU]K
8tÊ_ì(öøÉ£û8" 5  YL:G>(O^T'ÃÍ&¹ÎN]FøO^TÖ²ºÍ'p5$ öøÉ£'5ù8ã,"$)ºÍ$"ð# 5$(åä¥`4û8ß$'1

¹ÎN]FøO^T Ö²'½ "p$ O^Tíß¯'5\^[]H}Ù'24Ö²c({s~5 óÍ&øÐv)v&0('&5 O^TøÞg  {s) øÐ djÊ8ê"÷Í&§yîy85$Û365 øÞü&4§yõË8é".${s)Ï65$'&5 ­Ä[2]'25$ (Çæ) FVMY]?(Ï6(Channeling Breaking)$ *6 øÞ 5ô
m(>~105A/cm2)8è5$Ö²' ÑÉhQXCSrÇ5$Û36 hQXCS8tÊ® wë¯$"ª6" 5[3] _¯ (2&Çæ) öøÉ£' ©Í&ù
8a5$'&4 (Ü¢8l"$)ð# 5 Ã' öøºÍ() pø(øÞñ8#55¡ 5
3# 5 e($7FVMY]?(Ï68â±5Èä)& ûÍ'ã,5-'¯¾)&
ï|(û#) <MZ=^g øYL:G>(³#30MeV)'25¬û6" 5GeVú#(Ô×Í&¬û)k& [2] ¤(°(áÚ#)©FVMY]?¬8¸r5$)#&  0 (2&Ý¿ ÇærÇ6* öøÉ£'0i3(ÌE-mail: tsuyoshi.suwada@kek.jp-176-

Proceedings of the 2nd Annual Meeting of Particle Accelerator Society of Japanand the 30th Linear Accelerator Meeting in Japan (July 20 - 22, 2005, Tosu Japan)*-,ü'-ÂÅ¼Þ¨ÂÅ-

3.1 Ý»ÃÕ4.1 ]G8^:6_SÝ»ÃÕ FXMZ^:·),āĂ
Ð±Î ÆòÕ æAZ=^(Ý»<110>)/Ñ,iÑAZ=^ 2.55mm (·þ0.0272X0),Ý»ÃÕuĂ, w uĂĄ>L5W_Dc (H,V)/ āĂ¥¢ ½,¢/´çĉ  A Z = ^  8GeV Ă  / u     > L 5
W_D/Ý» +  āĂÐ
3.2 uĂ±ü~(÷}üP=20MeV/c)/ØĊ V/½pH +C8X^ÝÁuĂ¿e Ý» ,u FX(]G8^:6_S)/ØÝ»P_V `MZ^:·¿e/ÌãÒ(AZ=^ä (on-axis) āĂÐ± ½+ý170µrad))+ ,%Ăå¢/
Q_9,¢  /,,,Ăåü/
(off-axis)Æ"Ü10n'ùÝ»),āĂ( 4UGD^C{~N^Ffþ û* h . ,]G8^:6_S
- a­P_Vî¹)+½Ăåüx¡(Lorentzianÿ¸R0GI) CR, CB),
3.2nC/bunch/ÃÕ%óô/â
·øÙ/Íª,OYW_D,ċu½Ăåü FXMZ^:¿e Ìñ, Ăåü,x¡~/ØÝÁ
P_V{~/ð½Ăå¢ * (Ĉ)èĈuĂ(8GeV)Ăå¿e/%&, /,Ā+uĂåü,k¯ #$`á*-Ó Ïï/Øso *-èĈĎuĂĂåüĂå¢½p
½pĂå¢ [A/cm2]
0.15 x104
1.2 x104
Ăåü [nC/bunch]
0.09
3.2

4.3 āĂÐ±čuĂåü/OYW_Dć/g<1^ĉ¾PMTËāĂÐ±ü/ØāĂÐ±ü on-axisāĂ¸ *off-axisāĂ¸/¤üà-,Ý»
3.3 āĂCT9I]W_D|Á)+zāĂ¸/è,ĂåüāĂCT9I]W_D/Ñ÷}üxÀêß
,¨NG92Y^J(BG) ®ö,¾Ć  BG¤  xÉ°/²āĂāĂ¸/Ë,[_?1I *ÔÐ,F3\Ð±ü BG¤ §ÂÅ¼Þ¨ÂÅ^=Rt/Y1I71Jìĉ¾tĂĆÝÁ u  Ă   Ă å ü (0.1nÚ(PMT)uy,ºPMT(ć<1^)
3.2nC/bunch)/OYW_DāĂÐ±ü/ËÝÁĆíÛvÆj,/ NDR0[D_/³uuyt/ÊédØ     -  u  Ă   Ă å  ¢ (0.15ºPMT(g<1^) %%uy,ĉ1.2x104A/cm2)Ûv āĂÐ±Ó Ïï¾PMT #$ wy,)ćĂ(HV)
ë&*-/Ø',/î¹āĂËE1KUG9\^B/rx×l,),3.4 \_@_),tĂqnÚÂÅ

AZ=^8GeVN^FĂP_V/uā¾ĆuĂåüÛ Ü30n',Ă  Ð ±  Ć / ç    u  Ă   Ă å ü (0.1PMT<1^/Ăåü¬½ú~,« 
3.2nC/bunchĂå¢0.15-1.2x104A/cm2)/OYW_,%āĂÐ±/ü~, HVkDāĂÐ±ü/ËÝÁĆíÛ,PMTwyăÞ¦¯/ÂÅ« vÆj +FXMZ^:Ö-/Ø),Č PMTõmÑt;_S[/õµÓ Ïï ë&*-/×ë\_@_(Advanced Photonic Systems, =438.7nm,
Q_9wy~140mW, O[C¡~60ps)/uPMTwy/ËÝÁ,āĂ¸ PMTwy[1] T.Suwada, et al., Procs. the 29th Linear Accelerator
AD¶-,ADCp PMT!uyt
Meeting in Japan, p.396.
üPMT<1^ÿ¸,PMTz,HV[2] R.A.Carrigan, presented at Int. Workshop on Relativistic/OYW_D\_@_¥¢,ADCp/
Channeling and Related Phenomena, Mar. 23, 2004,Ë,)+ÂÅH_D/©,  ,Frascati, Italy.
[3] R.Hofstadter, “The Atomic Accelerator”; HEPL-560 (1968).
ÂÅH_DċÄą£/Ñ½cbÈ/ú[4] T.Suwada, et al., Phys. Rev. E 67 (2003) 016502.
ÑÂÅ¼Þ/Ç&)āĂÐ±-177-

Proceedings of the 2nd Annual Meeting of Particle Accelerator Society of Japanand the 30th Linear Accelerator Meeting in Japan (July 20 - 22, 2005, Tosu Japan)

3

Rocking-Curve Peak Width [mrad]

1.5 104

2

Charge Density [A/cm ]Experimental data

1 104

5000

Vertical scan (High Gain PMT)
Horizontal scan (High Gain PMT)
Vertical scan (Low Gain PMT)
Horizontal scan (Low Gain PMT)

2.5

2

1.5

1

0.5

00
0

0.5

1

1.5

2

2.5

3

3.5

00.51Charge [nC]

%CI!.?*

?<=

1.5

2

2.5

3.5

Charge [nC]-?<,2(# %FI!.?*
"/0?<=-(#2000

HV500V data
HV500V fit
HV600V data
HV600V fit
HV700V data
HV700V fit
HV800V data
HV800V fit
HV900V data
HV900V fit

450
ADC counts
ADCcounts

Positron yield [arb. unit]

3400
350
300
250

1500

1000

200

500

-44-46

V-48

angle-50[m -52rad -54 12]16141820leH ang

220][mrad01020304050

Laser intensity [arbitrary unit]
Laser
Intensity [arb. unit]%DI(H,V)$1@ >?*9432"/!.?<= 1nC/bunch%GI;6

?*':

78

30
Exp. data with High Gain PMTExp. data with Low Gain PMT

Horizontal scan
25

Positron Yield [a.u.]

Positron Yield [a.u.]






20

15

105



00














Rotational Angle [mrad]%EIH$ &+B

0.5



AV  5)

1

1.5

2

2.5

3

3.5

Charge [nC]

%HI!.?*(#-178-?<=->?*94=

Proceedings of the 2nd Annual Meeting of Particle Accelerator Society of Japanand the 30th Linear Accelerator Meeting in Japan (July 20 - 22, 2005, Tosu Japan)-179-