Sks Minus status SKS meeting 2008118 Sks Minus

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

Sks. Minus setup Sks. Minus Ø SDC 1~4 : Beam position measurement Ø STOF : Time-of-flight Ø SAC & BAC: K- beam veto and p- ID (n=1. 03) Background Veto _ Ø SMF : from n Ø SP 0 : p- from K- → p- + p 0 m- K- → m- + Target ~20 g/cm 2

Sks. Minus elements Test and production in progress Ø Drift chambers : BD(SDC 3, 4), SDC 1, 2 Ø Timing counters : STOF, BH 2 Ø Beam decay veto counters : SMF Design Ø Aerogel Cherenkov counters : BAC, SAC Ø Beam decay veto counters : SP 0 Ø Targets : 4 He target

In progress

Drift chambers BD (SDC 3&4) SDC 1&2

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

BD status Ø Plateau : 1950~2250 V → 2150 V operation Ø Uniform wire tension

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

SDC 1 and 2 Ø SDC 1 : Sks. Plus SDC 2 (400× 200 mm 2, 3 mm spacing, xxuuvv planes) n After Okamura’s chamber ? Ø SDC 2 : Old SDC 2 (560× 150 mm 2, 5 mm spacing, xxuu planes) n Test and repair from Jun (or after ? )

Frame and readout electronics Ø Frame (Upstream and Down stream) n n Not yet designed : SKS configuration, common frames ? Plan of production : From Jun Ø Readout electronics n n n Fryeburg : Special preamp with modification BNL : Present readout with modification SDC 1 and SDC 2 : Present readout ⇒ TKO TDC

Schedule 1 Freiberg repair BNL 3 2 4 repair 7 8 9 10 test repair SDC 1 Readout (cable, connector) 6 test SDC 2 Frame 5 test ? ? ? Design Production and test 11 12

STOF, SMF, BH 2

STOF Ø BT cannot be used…. n Dt ~100 ps(rms), 30 cm attenuation length Ø Present SKS TOF counter n Dt ~80 ps(rms), 100 cm attenuation length ⇒To add Present SKS counters n n Present 15 segments ⇒ STOF 30 segments + 15 segments Frame design and production : From now n The similar design with present SKS TOF frame BH 2 and BP : Just production

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

BH 2 & BP Ø BH 2 : Start counter (time zero) n 1 segment with booster PMT Ø BP : Beam decision counter n 1 segment : Fiber readout ? BAC 1 BAC 2 SAC Beam BH 2 BP Target

Design SP 0 SAC, BAC Target

SP 0

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

SP 0 design Ø Range counter (E 559) based n n 1 Scinti、PMT: OK + (Iron shield) Light guide or Fiber ? Lead : How to get (600 kg) Frame : How to fix lead ? 3 2 design 4 5 6 7 easy test ? production Range counter disassembly 8 9 10 11 12

AC counters SAC, BAC

AC design Index : n=1. 03 ~4 photons Ø BAC 1, 2 n 160× 30× 75 mm Ø SAC 1 : n 300× 90× 75 mm Ø SAC 2 : n 360× 100× 75 mm With 2 inch fine mesh PMT (F~72 mm)× 8 Inside : White box, w/ or w/o reflector Design and test start from Mar

AC test and schedule Ø To test largest size (SAC 2: 360× 100× 75 mm) n n 1 Cosmic ray test Efficiency by LNS beam Inside w/ or w/o reflector Other In-beam test ? 2 3 4 5 test 6 7 test design production improvement 8 9 test improvement 10 11 test improvement 12

4 He target Target size : f 150 mm× 250 mm Ø No progress Ø Just start to design (E 549, E 570 target)

Summary Ø Three important elements n n n BD in progress : 1 detector finished in February. SP 0 design will be finished soon. He target is just designed stage. Ø Other elements n n Timing counters are production stage. : STOF, SMF, BH 2, BP AC counters (BAC and SAC) are designed stage.

Others

Readout channels Ø DC : total 2608 ch (T) n n SDC 1 (xxuuvv) : 128 ch× 6 = 768 ch SDC 2 (xxuu) : 112 ch× 4 = 448 ch SDC 3 (xxuuvv) : 108 ch× 2 + 120 ch× 4 = 696 ch SDC 4 (xxuuvv) : 108 ch× 2 + 120 ch× 4 = 696 ch Ø Timing counter : total 64 ch (A&T) n n STOF : 30 segment : 60 A&T BH 2, BP : 2 ch× 2 = 4 A&T Ø Veto counter : total 88 ch (A&T) n n SMF : 24 + 14 segments : 38 A&T SP 0 : 5 segments× 10 layers : 50 A&T Ø AC : total 8 ch (A&T) n n SAC : 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