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JHF 原子核　実験計画とエレキに対する要求 Strangeness Physics を中心に

JHF 原子核　実験計画とエレキに対する要求 Strangeness Physics を中心に. 東北大理 高橋俊行. 1. JHF で行う実験 Strangeness Nuclear Physics Part 2. Beam Line Detector System 3. DAQ System への要求. Experimental Facility – 50GeV PS –. PS Parameter Intensity 3.2 x 10 14 ppp Duration 3.42 sec Extraction 0.7 sec.

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JHF 原子核　実験計画とエレキに対する要求 Strangeness Physics を中心に

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  1. JHF原子核　実験計画とエレキに対する要求 Strangeness Physics を中心に 東北大理 高橋俊行 1. JHF で行う実験 Strangeness Nuclear Physics Part 2. Beam Line Detector System 3. DAQ System への要求

  2. Experimental Facility – 50GeV PS – PS Parameter Intensity 3.2 x 1014 ppp Duration 3.42 sec Extraction 0.7 sec Beam Lines ( １期計画 ) K1.8 K1.1 P [GeV/c] 1.0 – 2.0 0.5 – 1.1 Intensity K-(1.8): 1.5x107 K-(1.1): 1.5x107 @1x1014 ppp K+(0.8): 1x107 Length [m] 40 25 K/p 2-5 Beam Lines ( ２期計画 ) HR: High Intensity: p 109 High Resolution: Dp/p = 10-4 Primary: Primary Beams of p & Ion High Intensity Kaon Beams are available !

  3. Strangeness Physic Programs 1. Study of S = -2 System 1-1. Spectroscopy of X Hypernuclei by (K-,K+) Reaction 1-2. Study of LL-Hypernuclei by Sequential Pionic Decays 1-3. Study of Double Strangeness Nuclei by an Emulsion-Counter Hybrid Method 2. Hyperon-Proton Scattering 2-1. Cross Sections for X-p Elastic and X-p -> LL Reaction 2-3. Polarization for Lp and S+p Elastic Scattering 3. High Resolution Spectroscopy of S = -1 Hypernuclei 3-1. g-Spectroscopy with Ge-Detectors (HyperBall) 3-2. High-Resolution Reaction Spectroscopy by (p, K+) Reactions

  4. 1-1. Spectroscopy of X Hypernuclei High Momentum Transfer Reaction -> well-separated peak structure (Single-particle States) X single particle potential, effective X N Interaction (K-, K+) Reaction at 1.8 GeV/c 1.2GeV/c for K+ Targets: 28Si, 58Ni, 208Pb Energy Resolution: 2MeV(FWHM) Intensity: 1 x 107 [/sec] Beam Spectrometer:Dp/p=2x10-4@1.8GeV/c Tracking Type, K- Selection K+ Spectrometer: Dp/p=2x10-4@1.2GeV/c 50 msr SKS + (D ) + Q Good Particle Identification

  5. 1-2. LL Hypernuclei by Sequential Pionic Decays High-Statistics LL Hypernuclei Detection by Counters X- Production by (K-,K+) Reaction Double L Compound States Formation Double L Fragment Detect Sequential Pionic Decays ( 2 monochromatic p- ) Medium Resolution Beam and K+ Spectrometer Beam Intensity: 1x107 [/sec] Pion Spectrometer: Dp=3MeV/c @ 100MeV/c Large Acceptance Cylindrical Detector System (CDS) Upgrade of BNL-AGS E906 10 times higher beam intensity

  6. 1-3. Double Strangeness Nuclei by an E-C Hybrid Method LL Interaction H-dibaryon ? E174 -> E373 -> JHF Exp. Obs. of LL 103 stopped X-events 104 events Hypernucleus Beam: 105K-/spill, K-/p- >10, small size K+ Spectrometer: Large Acceptance, Short Flight Path ( KURAMA) Tracker: double-sided SSD ~10mm resolution SCIFI <105 Hz Operations Large-size Image Data 3-stage Trigger System & Fast DAQ System

  7. 2. Hyperon Proton Scattering Baryon-Baryon Interaction extending to SU(3) space Meson Exchange Picture or Quark Picture ? Lack of the Experimental Data E251: S+p ->S+p E289: S+p ->S+p, Lp ->Lp, S-p ->S-p using SCIFI Detector as Production and Scattering Targets JHF: X- production via (K-, K+) at 1.6 GeV/c 1x107 [/sec] Observe X-p ->X-p, X-p -> LL

  8. 3.1 Hypernuclear g-Ray Spectroscopy Observe Hypernuclear Levels with Ultra-High Resolution of 2 keV by Ge Detectos Level Energy -> ( Effective ) YN (Spin-Dependent) Interaction B(El), B(Ml) -> Impurity Effects, Nuclear Medium Effects Table of HyperIsotopes Hypernuclear States Identification (K-, p-) Reaction with 3MeV Resolution Beam: K- 0.8/1.1/1.8GeV/c, 2x107 [/sec] p-Spectrometer: Large Acceptance Good Resolution HyperBall: Large Solid Angle as 40% of 4p Segmented Ge Detectors + BGO Suppressors Transistor Reset Type Preamplifier + UHA

  9. 3.2 Reaction Spectroscopy with (p, K+) Reaction A few 100 keV Resolution Reaction Spectroscopy of S=-1 Hypernulei Fine Structures above Particle-Decay Threshold <->g-Spectroscopy Coulomb-Assisted Hybrid S-Hypernuclear Bound States Neutron-Rich L Hypernuclei by Two Step (p-, K+) Reaction • Beam Line 1–1.5 GeV/c • 109 [/sec] Intensity • 10.6 [cm/%] Dispersion • K+ Spectrometer • Focal Plane Type • Dp/p = 10-4 • Vert. Mag. (R33): -3.084 • Mom. Accpt.: ±5% • Solid Angles: 16msr • K+ Survival: ~0.1

  10. JHFで要求されること – Beam Tracking 1 – • Beam Intensity 107 [/sec] 以上 • これまでの経験 5x106[/sec] with 5mm spacing DC & S.H.TDC (K6) • 200mm(s)程度の位置分解能 • （低物質量） • <2x107[/sec]: 3mm spacing DC + M.H.TDC • 1mm MWPC >2x107[/sec]: 0.5mm MWPC Scintillation Fiber (0.5-1.0mm Pitch) Hodoscopes ? ビームサイズ10cmでのWireあたりの平均Rates Gate Time Rates/Wire@107[Hz] 3mm DC 100 ns 3x105 [Hz] 1mm PC 50 ns 1x105 [Hz] 0.5mm PC 50 ns 5x104 [Hz] MHzに近いRateでの動作が求められる。 PreAmp. 数10ns のIntegration Time Amp. P.Z.C & Base Line Restore

  11. JHFで要求されること – Beam Tracking 2 – K1.8 Beam Spectrometer (QDQDQ) Effective Area: 20cm x 10cm 程度として Entrance: 0.5mm PC ( x, u(30), v(-30), x’ ) x 2 x: 400 u,v: 512 Total: 3648 channels Exit: 3mm DC ( x, x’, u(15), u’, v(-15), v’ ) x 2 x,u,v: 64 Total: 768 channels System全体( PreAmp. Discri, TDC, etc )のコンパクト化が重要 1. SONY ASD chip (4ch./chip)

  12. Trigger Rates (K-,K+) Reaction の実験 AGS-E906 (K-,K+) 48D48 Spectrometer ( msr) Be (15cm, ) Target 2 AC, 1 LC 600 Triggers / 1.5x106 K- これから推測すると、JHF( several x 107K-)では、 数kHz~10kHzの1st Level Trigger Rates (K-,p-) Reactionの実験 K- -> m-n Decay が Main Background Trigger Decay Arm ( Ge-detector, etc ) をRequire しても、2kHz程度 2nd Level ( Mass Selection Trigger )　が必須 それでも、数kHzで取れるDAQSystemが必要 ADC, TDC のConversion Time 10ms以下

  13. Data Size Beam & Scattered Spectrometer: 400 words/event with Pedestal Suppression これにCoincidence Detectorのデータが加わる。 HyperBall: 30 words * Multiplicity CDS: 100 words SSD: ~50 words [ 3 Charge Info./track ] SCIFI Image: Very Large ( Transfer Time 45ms for 10MHz Clock) Spectroscopy Exp. でも A) 400 [words/event] x 2000 [triggers/sec] = 3.2 [Mbytes/sec ] B) 1 PS-Cycleでは、2.5 Mbytes を 2 sec. 程度で読み出し、記録する。 B) については、現在、将来の計算機Powerを考えれば、問題ない。 A) については、TKO ( 0.5~ 1?ms/cycle )では、苦しい。 FASTBUS ( 10Mwords/sec ) 程度の転送Speedが必要

  14. TKO の限界 Dead time 10% で、2kHz でとるためには、ConversionとReadoutを含めて、 50 msでしか許されない。 0.5 ms/cycle だとすると、Conversion Timeを無視しても、100 scan　しかできない。 1. Conversion Time: Module 全体平均で、10 ms　のADC, H.R.TDC, M.H.TDC 2. Module にData Suppressionの機能を持たせる。 FIFO 形式で読み出せる。 3. Multi Event Buffer を持たせる？ 4. 10 M words/sec 以上のSpeedのReadout Bus 5. PS Cycle 中のData Buffering

  15. まとめ 1. JHFでは、これまでにないほどの強度のK-ビームが得られ、 S = -2ハイパー核の高統計実験 YN散乱の高統計実験 S=-1 ハイパー核での超高分解能・高統計実験 が可能となり、Strangeness 核物理の分野が飛躍的に進む。 核力の問題、高密度物質（Strangeness Matter）のなぞに迫る。 2. 10 MHz を超える Rate のビームを扱う検出器が必要。 High Rate, Compact な Chamber Readout System 3. Trigger Rates 2kHz , 500 words/event をDead Time 10%以下で取れる DAQ System が必要。

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