20-40MeV??????4He??????

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20-40MeV??????4He??????
????????????????????? 2008?12?23?-25?_at_RCNP

• ???? ?????????
• ? ??

• Introduction?????
• ??????
• ??????????????????
• 2838MeV???????_at_??????(?????)
• ????????

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Collaborators
H. Utsunomiya, H. Akimune Department of
Physics, Konan University Y. Nagai Nuclear
Science and Engineering Directorate, Japan
Atomic Energy Agency T. Mochizuki, S. Miyamoto,
K. Horikawa Laboratory for Advanced Science and
Technology for Industry, University of
Hyogo M. Fujiwara Research Center for Nuclear
Physics, Osaka University T. Hayakawa, T.
Shizuma Kansai Photon Science Institute, Japan
Atomic Energy Agency
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Previous works 4He(g,p)3H 3H(p,g)4He
(detailed balance)
PRC72, 044004 (2005)
? Gorbunov 62 ? Arkatov 78 ? Bernabei 88
Hoorebeke 93 Gardner 62 Gemmell 62 ?
Meyerhof 70 ? McBroom 82 ? Calarco 83 ?
Feldman 90 ? Hahn 95
?????????? PerryBame1955?normalize ??????
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Previous works 4He(g,n)3He 3He(n,g)4He
(detailed balance)
? Gorbunov 62 ? Berman 71 Malcom 73 ? Irish
73 ? Nilsson2005 ? Ward 81 ? Komar 93
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Photodisintegration of 4He have been studied by
means of monochromatic g, bremsstrahlung,
radiative capture...
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?????????
3H(p,g)4He ????????????? ????????(???????) ????????(gt20MeV)???????? 3H(p,n)3He (s540mb_at_3MeV) ???????????
3He(n,g)4He ????????? ????????(????) ????????(gt20MeV)???????? ????????????????
4He(g,p)3H ??????????????? ??????????????
4He(g,n)3He ??????????????? ????????????? ????????(??????????)
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3H(p,g)4He g-ray spectrum (Perry Bame, PR99,
1368 (1955))
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Energy distributions of bremsstrahlung photons
Bremsstrahlung, Annihilation g
Energy spectrum of photo-proton (Si??????)
e-, e
e-,e proton
? Tp 6MeV ? Eg 24MeV
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Laser Compton-scattered g-ray (GSO scintillator
spectrum)
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Lund-Glasgow experiment 4He(g,n)3He
Nilsson et al., PLB626, 65 (2005), PRC75, 014007
(2007)
MAX-lab Tagged photon Liquid He target
Neutron TOF
Radiator
Liq. He target
g
e-
n
Tagger
Magnet
Liq. scintillator
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GEANT3 simulation
Detection threshold En4.5MeV
Attenuation-1
Eg 26MeV
Scattering
Detection Efficiency
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?????? ????????
???
Yp ?????? Yg ?????? ep ??????????? eg
??????????? N4He ??4He???

• ????????(???????????)????????? Yp, Yg
• ?????????????????? ? Yg
• ??????????????? ? N4He
• ?????????????? ? ep, eg
• ???????????????????? ? Yp

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??????

• ????????(???????????)????????? Yp, Yg
• ? ????????????????
• ?????????????????? ? Yg
• ? ???????????????????????????
• ??????????????? ? N4He
• ? ???????????????????? (event by event)
• ?????????????? ? ep, eg ? 100????????
• ?????????????????? ? Yp
• ? ???????????????????
• ?????????????????????????
• Consistency ?????

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Experiment with quasi-monochromatic g at
NewSUBARU
Laser Compton-scattered g-ray Eg 16
40MeV, Fg 4104 /sec, FWHM9, P100
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Time Projection Chamber
T. Kii, T. Shima, T. Baba, Y. Nagai, NIM A552
(2005) 329
Target gas He CH4 (CD4)
W 4? , ? ?100 high efficiency track
shape, dE/dx ? event ID, ds/dW, asymmetry
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Systematic errors

• ep (detector efficiency) 98 99 ? de 1
  2
• N4He (target thickness) dN 1
• ( effective volume 1, gas
  density ltlt 1 )
• Fg (g-ray flux) dFg 2
  

TOTAL 4
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Measurement of g-ray intensity with pile-up
analysis
BGO pulse-height spectrum (eg gt 99.8)
pulse rate fpulse 10kHz pulse width
lt10ns
Fg 3000104 /sec BGO f26 shaping time
1ms
of photons per pulse ? Poisson distribution
Multiplicity Nphoton
Fg Nphoton fpulse
dFg / Fg 2
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???????????????????????????????(?)
(????0.5W)
(????1.5W)
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???????????????????Nphoton ?????
Nphoton 5.260.10 (1.9)
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Target thickness (N4He)
Gas density (r) TPC effective length (L )
Gas density (r) ? Pressure (P ), Temperature (T
) dP 0.5 Torr at 1000 Torr (0.05) dT
1 K at 300 K (0.3)
Time variation (10000s) Dr/r lt 0.05
dr/r (absolute) 0.3
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Distribution of vertex position in drift
direction ( g-ray beam direction)
(z-coordinate)
dL 2 mm ? dL/L 1 ? dN/N 1
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Event Selection

• Vertex position true ? background
• Number of tracks (g,p) ? (g,n) ? (g,2a)
• Track length p, d, 3He, 4He ? 11B,
  11C
• dE/dx p, d ? 3He, 4He
• Track angle two-body decay ?
  multi-body decay

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4He photodisintegrations
4He(g,p)3H
4He(g,n)3He
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12C photodisintegrations
12C(g,p)11B
12C(g,n)11C
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Three-body decays
4He(g,pn)2H
12C(g,2a)4He
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D(g,n)p
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Pulse Height Spectrum
4He(g,n)3He
4He(g,p)3H
12C(g,p)11B
12C(g,n)11C
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4He(g,p)3H (preliminary)
? RCNP-AIST2005 (PRC72, 044004) l351nm (3rd),
Ee0.8GeV
? RCNP-AIST2005 (PRC72, 044004) l351nm (3rd),
Ee0.8GeV
? RCNP-AIST2005 (PRC72, 044004) l351nm (3rd),
Ee0.8GeV ? RCNP-NewSUBARU l532nm
(2nd), Ee0.97GeV ? RCNP-NewSUBARU
l1064nm (fund.), Ee1.46GeV ? RCNP-NewSUBARU
l532nm (2nd), Ee1.06GeV
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4He(g,n)3He (preliminary)
? RCNP-AIST2005 (PRC72, 044004) l351nm (3rd),
Ee0.8GeV ? RCNP-NewSUBARU l532nm
(2nd), Ee0.97MeV ? RCNP-NewSUBARU
l1064nm (fund.), Ee1.46GeV ? RCNP-NewSUBARU
l532nm (2nd), Ee1.06GeV ? Lund 2005-2007
(PRC75, 014007) tagged photons
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4He(g,pn)d(preliminary)
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D(g,n)p (preliminary)
Not for normalization, just fire insurance!
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Consistency
Eg ? Elaser Ee2

• 3???????????????????????????????
• 800MeV e- NdYLF 351nm (?3???) (???)
• 976MeV e- NdYVO4 532nm (?2???)
• 1.46GeV e- NdYVO4 1064nm (???)
• ????????????2?????TPC?????????????
• ??????? 4He(g,p)3H, 4He(g,n)3He ???????(????)
• ??????? D(g,n)p ???????????????????

(??????)
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Comparison with theory 4He(g,n)3He
?? RCNP-AIST ??? RCNP-NewSUBARU ? Lund
2005-2007 Trento (Lorentz-Integral-Transf
orm) PR C69 044002 (2004) Bonn
(Faddeev-AGS) NP A631 210c (1997)
Londergan-Shakin (C.C. Shell Model) PRL28 1729
(1972)
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????????

• 2???????/3??????????/2?????? ??
• ????????????????
• ?????????3033MeV??
• ?????????????????(3He??)
• 2000???????2???????1????????????
• ?????
• 4He Eg26MeV???????????????? (q,f)????????
• ????????????? MAX-lab ????????????
• 3He????????????????
• ????????????????? 11.5GeV?? 0.781.5GeV???
• ? Eg 10.739MeV ?????????

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Strategy
Photon beam Tagged photon Backscattered-g
Detection method Neutron detection Charged-partic
le detection
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NewSUBARU LCS-g Detector for (g,n) (Konan
Univ.)
4p neutron counter
Beam dump (NaI(Tl) detector)
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(No Transcript)
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3He photodisintegration cross sections
? RCNP-AIST Naito et al. PR C73 034003 (2006)
Theory Faddeev ?????
???? LIT ????
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Angular distributions 4He(g,p)3H_at_32MeV
f
q
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p-3H angular correlation
Eg(max) 32MeV
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Energy calibration (measured with Ge)
Pulse Height spectra of 45 Ge-detector
Eg vs P.H.
(P.H.)
dEg 0.7MeV at 33MeV
standard source
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Energy distribution
NaI(Tl) 6f5 Collimator f3mm
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Interval of drift time signals
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4He(g,n)3He / D(g,n)p Energy loss spectra