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Polarized Positron Experiment at KEK-ATF. JPSMeeting2005. KEK ATF におけるパルス偏極陽電子生成3 〜 偏極陽電子生成とその偏極度測定 〜. 浦川順治、 @ 大森恒彦、奥木敏行、栗原良将、 黒田隆之助 A 、斉藤卓 A 、坂上和之 A 、広瀬立成 A 、 福田将史 B 、鷲尾方一 A. 高エ研、早大理工総研 A 、放医研 B. Pol. e + Production. Design values. N g = 1 x 10 7 /bunch. - PowerPoint PPT Presentation
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Polarized Positron Experiment at KEK-ATFPolarized Positron Experiment at KEK-ATF
JPSMeeting2005JPSMeeting2005
KEK ATF におけるパルス偏極陽電子生成3 〜偏極陽電子生成とその偏極度測定〜
浦川順治、 @ 大森恒彦、奥木敏行、栗原良将、黒田隆之助 A 、斉藤卓 A 、坂上和之 A 、広瀬立成 A 、福田将史 B 、鷲尾方一 A
高エ研、早大理工総研 A 、放医研 B
Pol. e+ Production
N = 1 x 107 /bunch
T(rms) = 31 psecCan NOT measure each e+
Polarimetry ?
Design values
Ne+ = 1 x 104/bunch (Ee+ = 25 to 45 MeV)Pol. e+ ~ 80 %
polarized e+
Measure e+ polarization : use Bremsstrahlung -ray
Pb conveter
-ray
E = 40 MeV
Measurement and Cross-Check Measurement
Cross-Check
non (Liner)
)Calculate A
)Calculate A
)Calculate A
e+ beam pol.(laser pol)
e- spin in iron (magnet pol.)
Calculate A
Calculate A
magnet pol.e+ beam pol.
A(0) : A(0)=0
Zero magnet current Not Equal No-polarization, due to residual magnetism
))
A(R) : A(R)= ~ + 0.7 %
A(L) : A(L)= ~ - 0.7 %
A(P) : A(P)= ~ + 0.7 %
A(N) : A(N)= ~ - 0.7 %
R
L
0
P
N
expected value
(MC)
CO2 Cherenkov
CO2 Cherenkov
Leakage B Feild e+ trajectry Acceptance
Mag. Pol. = P
Mag. Pol. = N
e+
e+
If e+ beam go just center of ma
gnet -> OK
CO2 Cherenkov
CO2 Cherenkov
Leakage B Feild e+ trajectry Acceptance
Mag. Pol. = P
Mag. Pol. = N
e+
e+
If e+ beam go off center, trajectry near magnet
may be different when we flip magnet.
Acceptance Correction Define: A(TP,TN) = (TP-TN)/(TP+TN)
A(TP,TN) = 0 from absorption in iron
A(TP,TN) = 0 acceptance affected by B field
) average transmission TP
magnet pol. e+ beam pol.
non
)nonaverage transmission TN
Use A(TP,TN) for acceptance correction
P
N
Measurement
Cross-Check
non (Liner)
)))
e+ beam pol. magnet pol.
magnet pol.e+ baem pol.
))
e+ polarization (e+ run): results
A(R)= +0.16± 0.28%
A(L)= -1.63± 0.28%
A(0)= -0.24± 0.28%
R
L
A(P)= +0.85± 0.28%
A(N)= -0.93± 0.28%
A(TP,TN) = -0.57± 0.17%
Acceptance Correction
0
P
N
preliminary
Measurement
Cross-Check
non (Liner)
)))
e+ beam pol. magnet pol.
magnet pol.e+ beam pol.
))
e+ polarization (e+ run): results
A(R)= +0.72± 0.28%
A(L)= -1.07± 0.28%
A(0)= +0.33± 0.28%
A(P)= +0.85± 0.28%
A(N)= -0.93± 0.28%
Acceptance Corrected by A(TP,TN)
R
L
0
P
N
preliminary
e+ polarization (e+ run)e- spin in Iron
e- spin in Iron
e- spin in Iron
e+ beam spin
e+ beam spin
e+ beam spinnon
A(R)= +0.72± 0.28%
A(L)= -1.07± 0.28%
A(0)= +0.33± 0.28%
preliminary results
W- target
Separationmagnet
e+
e+
e-
W- target
e+Separation
magnet
polarized
e-
e-
e+ run e- run
We did e- run, also.
Measurement
Cross-Check
non (Liner)
)))
e- beam pol. magnet pol.
magnet pol.e- beam pol.
))
e- polarization (e- run): results
A(R)= +0.81± 0.28%
A(L)= -0.91± 0.27%
A(0)= -0.26± 0.27%
A(P)= +0.76± 0.27%
A(N)= -0.96± 0.27%
A(TP,TN) = -0.12± 0.16% NO correction is necessary
Acceptance Correction
R
L
0
P
N
preliminary
e- polarization (e- run)e- spin in Iron
e- spin in Iron
e- spin in Iron
e- beam spin
e- beam spin
e- beam spinnon
A(L)= -0.91± 0.27%
A(0)= -0.26± 0.27%
A(R)= +0.81± 0.28%
preliminary results
Polarized Positron Experiment at KEK-ATFPolarized Positron Experiment at KEK-ATF
JPSMeeting2005JPSMeeting2005
まとめ1)レーザー光の偏極が、 γ 線へ、そし
て対生成された e+ と e- へと伝達されていく事が確認された。
2) 短パルス高強度の偏極 γ 線、 e+ 、 e- の偏極測定法が確立できた。
3) 陽電子の透過率のアシンメトリーは予想値である ~ 0.7 % に一致した。
--> 偏極度 ~80% の陽電子ビームが得られた。
ここで終わり。これから後はバックアップ
i) proof-of-principle demonstrations
ii) accumulate technical informations: polarimetry, beam diagnosis, …
Experiment@KEK
T = 31 p sec.T = 31 p sec.
T = 31 p sec.