1. SksMinus status SKS meeting 2008/1/18 白鳥昂太郎

2. SksMinus setup SksMinus  STOF : Time-of-flight  SAC & BAC: K - beam veto and  - ID (n=1.03)  SDC1~4 : Beam position measurement Background Veto  SMF :  - from K - →  - +  SP0 :  - from K - →  - +  0 _ Target ~20 g/cm 2

3. SksMinus elements Test and production in progress  Drift chambers : BD(SDC3,4), SDC1,2  Timing counters : STOF, BH2  Beam decay veto counters : SMF Design  Aerogel Cherenkov counters : BAC, SAC  Beam decay veto counters : SP0  Targets : 4 He target

4. In progress

5. Drift chambers BD (SDC3&4) SDC1&2

6. BD repair status  Freiberg (XX,UU,VV) 3 layers finished (X,U,V) The other 3 layers : repair in Jun → Test in Feb  BNL (XXXX,UU,VVV → XX,UU,VV) Feb ~ Apr : repair Apr ~ May : test Repair routine is fixed. All sense wire exchange : 20  m → 25  m

7. BD status  Plateau : 1950~2250 V → 2150 V operation  Uniform wire tension

8. BD test  Efficiency and resolution test by cosmic ray FUJI beam line ?  DAQ with TKO MHTDC Test and study how to use TKO MHTDC 3377 by CAMAC is easy… Goal : Less than 400  m (rms) resolution (~300  m is possible) ＊ Where do we test ? ⇒ East counter hall ?

9. SDC1 and 2  SDC1 : SksPlus SDC2 (400×200 mm 2, 3mm spacing, xxuuvv planes) After Okamura’s chamber ?  SDC2 : Old SDC2 (560×150 mm 2, 5 mm spacing, xxuu planes) Test and repair from Jun (or after ?)

10. Frame and readout electronics  Frame (Upstream and Down stream) Not yet designed : SKS configuration, common frames ? Plan of production : From Jun  Readout electronics Fryeburg : Special preamp with modification BNL : Present readout with modification SDC1 and SDC2 : Present readout ⇒ TKO TDC

11. Schedule 12 34 567 8 910 1112 Freiberg BNL repair test repair test Frame Design Production Readout (cable, connector) SDC2 repairtest SDC1????? Design Production and test

12. STOF, SMF, BH2

13. STOF  BT cannot be used….  t ~100 ps(rms), 30 cm attenuation length  t ~100 ps(rms), 30 cm attenuation length  Present SKS TOF counter  t ~80 ps(rms), 100 cm attenuation length  t ~80 ps(rms), 100 cm attenuation length ⇒ To add Present SKS counters Present 15 segments ⇒ STOF 30 segments Present 15 segments ⇒ STOF 30 segments + 15 segments + 15 segments Frame design and production : From now The similar design with present SKS TOF frame The similar design with present SKS TOF frame BH2 and BP : Just production

14. SMF (K→  veto) Timing counter  FTOF(KURAMA) + BT  BT×14 segments Iron block  Iron beam shield  Frame design is not difficult. BT test ⇒ Usable. SMF Iron block BT FTOF

15. BH2 & BP  BH2 : Start counter (time zero) 1 segment with booster PMT 1 segment with booster PMT  BP : Beam decision counter 1 segment : Fiber readout ? 1 segment : Fiber readout ? Target BH2 BAC1BAC2 SAC Beam BP

16. Design SP0 SAC, BAC Target

17. SP0

18. SP0 (K→  0 veto) Beam decay background veto SP0 :  - from K - →  - +  0 Performance 80% of  events rejected (enough) 80% of  events rejected (enough) Accidental hits from background Multi-layer hit, total energy deposit Multi-layer hit, total energy deposit OK : Neutron, low energy gamma, mesonic-decay OK : Neutron, low energy gamma, mesonic-decay Other charged particles ⇒ Charge veto Other charged particles ⇒ Charge veto NO : Mesonic-decay :  0 (~20% kill @ 4  He) NO : Mesonic-decay :  0 (~20% kill @ 4  He)

19. SP0 design 12 34 567 8 910 1112 designeasy test ? production Range counter disassembly  Range counter (E559) based Scinti 、 PMT: OK + (Iron shield) Scinti 、 PMT: OK + (Iron shield) Light guide or Fiber ? Light guide or Fiber ? Lead : How to get (600 kg) Lead : How to get (600 kg) Frame : How to fix lead ? Frame : How to fix lead ?

20. AC counters SAC, BAC

21. AC design Index : n=1.03 ~4 photons  BAC1,2 160×30×75 mm 160×30×75 mm  SAC1 : 300×90×75 mm 300×90×75 mm  SAC2 : 360×100×75 mm 360×100×75 mm With 2 inch fine mesh PMT  ~72 mm)×8 Inside : White box, w/ or w/o reflector Design and test start from Mar

22. AC test and schedule  To test largest size (SAC2: 360×100×75 mm) Cosmic ray test Cosmic ray test Efficiency by LNS beam Efficiency by LNS beam Inside w/ or w/o reflector Inside w/ or w/o reflector Other In-beam test ? Other In-beam test ? 12 34 567 8 910 1112 designproduction test improvement test improvement test improvement

23. 4 He target Target size :  150 mm×250 mm  No progress  Just start to design (E549, E570 target)

24. Summary  Three important elements BD in progress : 1 detector finished in February. SP0 design will be finished soon. He target is just designed stage.  Other elements Timing counters are production stage. : STOF, SMF, BH2, BP AC counters (BAC and SAC) are designed stage.

25. Others

26. SKS 移動 : Pivot ピボット。ここに回転中心用ジグを設置 支持装置を設置 設置前設置後 支持装置 (L 字 ) 回転中心 To produce SksMinus 支持装置 (L 字 )

27. SKS 移動 : 油圧ジャッキ, 腕 油圧ジャッキ用の腕 設置前設置後 腕 油圧ジャッキ 押すときには上下に動かないように 固定するジグが必要。 SKS の壁に付 ける。

28. Readout channels  DC : total 2608 ch (T) SDC1 (xxuuvv) : 128 ch×6 = 768 ch SDC1 (xxuuvv) : 128 ch×6 = 768 ch SDC2 (xxuu) : 112 ch×4 = 448 ch SDC2 (xxuu) : 112 ch×4 = 448 ch SDC3 (xxuuvv) : 108 ch×2 + 120 ch×4 = 696 ch SDC3 (xxuuvv) : 108 ch×2 + 120 ch×4 = 696 ch SDC4 (xxuuvv) : 108 ch×2 + 120 ch×4 = 696 ch SDC4 (xxuuvv) : 108 ch×2 + 120 ch×4 = 696 ch  Timing counter : total 64 ch (A&T) STOF : 30 segment : 60 A&T STOF : 30 segment : 60 A&T BH2, BP : 2 ch×2 = 4 A&T BH2, BP : 2 ch×2 = 4 A&T  Veto counter : total 88 ch (A&T) SMF : 24 + 14 segments : 38 A&T SMF : 24 + 14 segments : 38 A&T SP0 : 5 segments×10 layers : 50 A&T SP0 : 5 segments×10 layers : 50 A&T  AC : total 8 ch (A&T) SAC : 2 ch×2 = 4 A&T SAC : 2 ch×2 = 4 A&T BAC : 2 ch×2 = 4 A&T BAC : 2 ch×2 = 4 A&T TKO TDC 32 ch TDC×82 TKO ADC 16 ch ADC×10 HR TDC 16 ch TDC×10