j-parc ハイパー核実験での ビーム tracking detector 高橋俊行( kek ) j-parc...
TRANSCRIPT
J-PARC ハイパー核実験でのビーム Tracking Detector
高橋俊行( KEK )
• J-PARC 施設の概要• 実験方法• 考えうる検出器
• 0.5mm spacing MWPC• Silicon Strip Detector
• まとめ
J-PARC Facility
Linac(350m)
3 GeV Synchrotron(25 Hz, 1MW)
50 GeV Synchrotron(0.75 MW)
Neutrino to Kamiokande
Nuclear and ParticleExperimental Facility
(HD-Hall)Materials and Life ScienceExperimental Facility
Nuclear Transmutation
J-PARC = Japan Proton Accelerator Research Complex
Phase 1 & Phase 2
Phase 1
Phase 2
Linac(Normal Conducting)
50 GeV PS
Neutrinos toSuperKamiokande
50 GeV PSExperimental Area3 GeV PS
(25Hz)
R&D for NuclearTransmutation
Linac(Superconducting)
3 GeV PSExperimental Area
30 GeV – 9A50 GeV – 15A
HDHall@Phase 1
K1.8K1.8BR
K1.1/0.8
T1
Primary Beam• 30GeV-9A
(180MeV LINAC)• 30GeV-15A
(400MeV LINAC) flat-top 0.7sec duration 3.64sec
Phase2• 50GeV-15A flat-top 0.7sec duration 3.52sec
Experimental Method
Beam Spectrometer
Target
Scattered ParticleSpectrometer
Decay ParticleDetectors (Opt.)
Measure trajectories, mom. of beam & scattered particles event by event.• Missing Mass (Hypernulcear states)
tracking detectors
Single Reaction SpectroscopyCoincidense with DPD
tagging hypernuclear states
Position resolution 200m – 1mm
SecondaryBeam
, K
(K,K+) -hypernuclei(K,) -hypernuclei
Beam Intensity (30GeV-9A)
K1.8 K1.8BR K1.1/0.8
Max. Mom. [GeV/c] 2.2 1.1 1.1
K Intensity [ppp]
1.8 GeV/c
1.1 GeV/c
0.8 GeV/c
2.0x106
1.0x105 2.0x106
4.0x105
2.0x106
4.0x105
K/ 2.6 (1.8GeV/c) 12 (1.1GeV/c) 4.7 (1.1GeV/c)
Beam Rate [/sec] 4.6x106 3.6x106 4.0x106
PS-K6 Beam Chamber• 5mm spacing DC• 2.4mm between anode wires
and cathode planes • Ar:iso-C4H10 = 80:20• 2.5mm drift length• <100ns drift time• Single-hit TDC• ~250m
K6 beam• 3.3x106 [/pulse]• 1.7sec flat top• ~2.0x106 [/sec]• 2-10cm @DC
J-PARC Phase1 では、充分使える。 Multi-hit TDC
upgrade of pre-amp. & discriminator
Beam Intensity (50GeV-15A)
K1.8 K1.8BR K1.1/0.8
Max. Mom. [GeV/c] 2.2 1.1 1.1
K Intensity [ppp]
1.8 GeV/c
1.1 GeV/c
0.8 GeV/c
9.6x106
6.0x105 9.1x106
1.7x105
9.1x106
1.7x106
K/ 2.3 (1.8GeV/c) 10 (1.1GeV/c) 4.3 (1.1GeV/c)
Beam Rate [/sec] 2.3x107 1.7x107 2.0x107
High rate への対応• Fine spacing wire chamber
– 0.5mm MWPC
• Semiconductor device– Silicon Strip Detector
• Fine segment scintillator hodoscope
Channel 当たりの計数率を下げる。Channel 数の増大低コスト化
0.5mm-Spacing MWPC(1998 東北大)
incident angle 10 deg.
Efficiency
Anode 12m 1.7mm
0.5mm
2600 36003200
50mm x 50mm
ClusterSize=2/CS=1
Ar:iso-C4H10=7:3 Plateau: 3.3-3.4kV CS2/CS1: 120%
Cathode
0.5mm MWPC – effect of freon -
3200
3400
3600
3800
4000
0 0.5 1 1.5 2 2.5 3
[%]
[V]
CBrF3
C2H6
not fullefficiency
Plateau 特性 Ar:iso-C4H10=7:3
0
25
50
75
100
125
0 0.5 1 1.5 2 2.5 3
[%]
CS2
/CS1
[%
]
CBrF3
C2H6
0 deg.
10 deg.
Cluster Size
CBrF3 1.5% で(安定)動作 Plateau 幅 300V Cluster Size も許容範囲
製造中止代替 Freon Gas の必要
SSD as focal plane detectorat J-Lab E89-009
scattered electron spectrometer of (e,e’K+) experiment
2x108 electrons /sec /10 SSDs’ 0.5mm pitchSingle-sided 144 strips/board
50mm x 74mm
t~300mbinary readout withmulti-hit TDC 2x10-7 /sec/20mm は充分可能
Double-sided structure を2面以上 -> Track 再構成可能
Radiation Damage ?
bulk conversion 1012 p/cm2
物質量と分解能への影響[g/cm2] X0 unit E [MeV] 0 [mrad]
Gas Chamber
Ar 30cm
Al 0.02mm
5.1 x 10
5.4 x 10
1.05 x 10
2.6 x 10
2.3 x 10
5 x 10 0.021 0.125
SSD Si
0.5mm x 2 2.33 x 10 1.1 x 10 0.47 0.68
Pla. Scin. Hodoscope 2cm 2.06 4.7 x 10 4.13 1.5
Eneagy loss stragling ~1/10 of EPosition resolution 0.3mm
Pla. Scin. Hodo は分解能の必要な実験には向かない。
まとめ• 東海に建設中の J-PARC で K ビームを利用した
ハイパー核の実験が計画されている。• Phase1 でのビーム強度では、既存の技術で対応
可能。• Phase2 のフル性能では、新たな技術が必要。
– Fine spacing wire chamber (0.5mm MWPC)• CBrF3 に代わる Freon Gas, さらなる R&D
– Semiconductor Device ( SSD )• 物質量と放射線耐性
回路系の低コスト化が必要