JHF Strangeness Physics 1 JHF Strangeness Nuclear Physics

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 1. JHF で行う実験 Strangeness Nuclear Physics Part 2. Beam Line Detector System 3. DAQ System への要求 高橋俊行

Experimental Facility – 50 Ge. V PS – PS Parameter Intensity Duration Extraction Beam Lines ( １期計画 ) P [Ge. V/c] Intensity @1 x 1014 ppp Length [m] K/p K 1. 8 1. 0 – 2. 0 K-(1. 8): 1. 5 x 107 40 2 -5 K 1. 1 0. 5 – 1. 1 K-(1. 1): 1. 5 x 107 K+(0. 8): 1 x 107 25 3. 2 x 1014 ppp 3. 42 sec 0. 7 sec 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 !

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 (Hyper. Ball) 3 -2. High-Resolution Reaction Spectroscopy by (p, K+) Reactions

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 Ge. V/c 1. 2 Ge. V/c for K+ 28 Si, 58 Ni, 208 Pb Targets: Energy Resolution: 2 Me. V(FWHM) Intensity: 1 x 107 [/sec] Beam Spectrometer: Dp/p=2 x 10 -4@1. 8 Ge. V/c Tracking Type, K- Selection K+ Spectrometer: Dp/p=2 x 10 -4@1. 2 Ge. V/c 50 msr SKS + (D ) + Q Good Particle Identification

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: 1 x 107 [/sec] Pion Spectrometer: Dp=3 Me. V/c @ 100 Me. V/c Large Acceptance Cylindrical Detector System (CDS) Upgrade of BNL-AGS E 906 10 times higher beam intensity

1 -3. Double Strangeness Nuclei by an E-C Hybrid Method LL Interaction E 174 Obs. of LL Hypernucleus H-dibaryon ? -> E 373 103 stopped X-events -> JHF Exp. 104 events Beam: 105 K-/spill, K-/p- >10, small size K+ Spectrometer: Large Acceptance, Short Flight Path ( KURAMA) Tracker: double-sided SSD ~10 mm resolution SCIFI <105 Hz Operations Large-size Image Data 3 -stage Trigger System & Fast DAQ System

2. Hyperon Proton Scattering Baryon-Baryon Interaction extending to SU(3) space Meson Exchange Picture or Quark Picture ? Lack of the Experimental Data E 251: E 289: 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 Ge. V/c 1 x 107 [/sec] Observe X-p -> X-p, X-p -> LL

3. 1 Hypernuclear g-Ray Spectroscopy Observe Hypernuclear Levels with Ultra-High Resolution of 2 ke. V by Ge Detectos Level Energy -> ( Effective ) YN (Spin-Dependent) Interaction B(El), B(Ml) -> Impurity Effects, Nuclear Medium Effects Table of Hyper. Isotopes Hypernuclear States Identification (K-, p-) Reaction with 3 Me. V Resolution Beam: K- 0. 8/1. 1/1. 8 Ge. V/c, 2 x 107 [/sec] p-Spectrometer: Large Acceptance Good Resolution Hyper. Ball: Large Solid Angle as 40% of 4 p Segmented Ge Detectors + BGO Suppressors Transistor Reset Type Preamplifier + UHA

3. 2 Reaction Spectroscopy with (p, K+) Reaction A few 100 ke. V 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 p Beam Line 1– 1. 5 Ge. V/c 109 [/sec] Intensity 10. 6 [cm/%] Dispersion K+ Spectrometer Focal Plane Type Dp/p = 10 -4 Vert. Mag. (R 33): -3. 084 Mom. Accpt. : ± 5% Solid Angles: 16 msr K+ Survival: ~0. 1

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 5 x 106[/sec] with 5 mm spacing DC & S. H. TDC (K 6) 200 mm(s)程度の位置分解能 （低物質量） <2 x 107[/sec]: >2 x 107[/sec]: 3 mm spacing DC + M. H. TDC 1 mm MWPC 0. 5 mm MWPC Scintillation Fiber (0. 5 -1. 0 mm Pitch) Hodoscopes ? ビームサイズ 10 cmでのWireあたりの平均Rates Gate Time Rates/Wire@107[Hz] 3 mm DC 100 ns 3 x 105 [Hz] 1 mm PC 50 ns 1 x 105 [Hz] 0. 5 mm PC 50 ns 5 x 104 [Hz] MHzに近いRateでの動作が求められる。 Pre. Amp. 数 10 ns のIntegration Time Amp. P. Z. C & Base Line Restore

JHFで要求されること – Beam Tracking 2 – K 1. 8 Beam Spectrometer (QDQDQ) Effective Area: 20 cm x 10 cm 程度として Entrance: 0. 5 mm PC ( x, u(30), v(-30), x’ ) x 2 x: 400 u, v: 512 Total: 3648 channels Exit: 3 mm DC ( x, x’, u(15), u’, v(-15), v’ ) x 2 x, u, v: 64 Total: 768 channels System全体( Pre. Amp. Discri, TDC, etc )のコンパクト化が重要 1. SONY ASD chip (4 ch. /chip)

Trigger Rates (K-, K+) Reaction の実験 AGS-E 906 (K-, K+) 48 D 48 Spectrometer ( msr) Be (15 cm, ) Target 2 AC, 1 LC 600 Triggers / 1. 5 x 106 Kこれから推測すると、JHF( several x 107 K-)では、 数k. Hz~10 k. Hzの 1 st 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、2 k. Hz程度 2 nd Level ( Mass Selection Trigger ) が必須 それでも、数k. Hzで取れるDAQ System が必要 ADC, TDC のConversion Time 10 ms以下

Data Size Beam & Scattered Spectrometer: 400 words/event with Pedestal Suppression これにCoincidence Detectorのデータが加わる。 Hyper. Ball: CDS: SSD: SCIFI Image: 30 words * Multiplicity 100 words ~50 words [ 3 Charge Info. /track ] Very Large ( Transfer Time 45 ms for 10 MHz 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 ( 10 Mwords/sec ) 程度の転送Speedが必要

TKO の限界 Dead time 10% で、2 k. Hz 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