Sks Minus status SKS meeting 2007510 Sks Minus

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Sks. Minus status SKS meeting 2007/5/10 白鳥昂太郎

Sks. Minus status SKS meeting 2007/5/10 白鳥昂太郎

Sks. Minus setup Sks. Minus Ø SDC 1~4 : Beam position measurement Ø STOF

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) Ø (SFV : K- beam veto) Background Veto _ Ø SMF : m- from K- → m- + n Ø SP 0 : p- from K- → p- + p 0 Target ~20 g/cm 2 Trigger = Kin×PIout Ø Kin = BH 1×BH 2×BAC Ø PIout = STOF×SAC×SFV×SMF×SP 0

Sks. Minus elements Ø Drift chamber : SDC 1, 2 & SDC 3, 4

Sks. Minus elements Ø Drift chamber : SDC 1, 2 & SDC 3, 4 Ø Timing counter: STOF, BH 2 Ø Aerogel Cherenkov counters : BAC, SAC (K- beam veto counter (timing counter) SFV) Ø Beam decay veto counters : SMF, SP 0 Ø 4 He target

SDC 3&4 Ø Ø 6 layer (x, x’, u, u’, v , v’ (±

SDC 3&4 Ø Ø 6 layer (x, x’, u, u’, v , v’ (± 30°)) (107× 6 ch) Size: 2140 mm× 1140 mm (20 mm wire pitch) 400 mm (rms) position resolution is assumed. Ø Highest counting rate @1. 5 Ge. V/c (500 k/spill) 70 k/spill ⇒ 100 k. Hz (0. 7 sec spill) 200 k/spill ⇒ 300 k. Hz (0. 7 sec spill) @ 1. 8 Ge. V/c

SDC 1&2 SDC 1 Ø Ø Ø 6 layer (x, x’, u, u’, v

SDC 1&2 SDC 1 Ø Ø Ø 6 layer (x, x’, u, u’, v , v’ (± 15°)) (128× 6 ch) Size: 384 mm× 200 mm (3 mm wire pitch) Target distance : 350 mm SDC 2 Ø Ø Ø 4 layer (x, x’, u, u’ (± 15°)) (112× 4 ch ? ) Size: 560 mm× 150 mm (5 mm wire pitch) Target distance : 575 mm 400 mm (rms) position resolution is assumed. Ø Who makes SDC 1 (Sks. Plus SDC 2) ? Size → Hyperball-J frame Ø Where is old SDC 2 ? The area size of DC in clean room is 400 mm. Old SDC is 560 mm in Hasegawa D thesis.

STOF design Ø STOF is made from BT used in E 930 experiment. All

STOF design Ø STOF is made from BT used in E 930 experiment. All counters of the present TOF is planned to be replaced. Ø BT 1 segment: 85× 2000× 50 (x, y, z) → Half size 85× 1000× 50 (x, y, z) ∴ 28 segment = 2380× 1000× 50 (x, y, z) BT: 40 segments → 26 segments can be used for other counters. Ø 150 ps(rms) time resolution is necessary.

BH 2 Ø Beam profile sx=20 mm, sy= 3 mm ⇒ 160 mm× 25

BH 2 Ø Beam profile sx=20 mm, sy= 3 mm ⇒ 160 mm× 25 mm (± 4 s) ØIt is possible for 1 segmented counter in E 13 experiment (700 k/spill). With PMT ⇒ ~400 mm BAC 2 BH 2 Beam BAC 1 200 mm Front image Target 100~300 mm 250~350 mm HBJ frame ~ 300 mm SAC The position of BH 2 is outside of the Hyperball-J frame, because of the conflict. For E 13 experiment we needs an other additional counter just before the target to reduce the trigger rate.

BAC & SAC Ø BAC: 160× 30× 75 (x, y, z) × 2 layers

BAC & SAC Ø BAC: 160× 30× 75 (x, y, z) × 2 layers Ø SAC: 300× 90× 75 (x, y, z) 1 or 2 layers (360× 110× 75 (x, y, z) ) Many fine mesh PMTs are needed. ⇔ PMTs conflicts Hyperball-J. Signal readout by fiber inside of AC

SMF & SP 0 Ø SMF: Iron blocks and scintillation counters Any counter can

SMF & SP 0 Ø SMF: Iron blocks and scintillation counters Any counter can be used. (BT ? ) Ø SP 0 : Range counter (E 559) Range counter with lead absorber shows good performance by rough simulation.

4 He target Ø The similar target used in K 5 is planned. Ø

4 He target Ø The similar target used in K 5 is planned. Ø Target size is as large as possible. (Target length is less than 300 mm) Ø Determination of size of detectors around the target and Hyperball-J is needed.

Time table Ø SDC repair、test Ø STOF test Ø SP 0, SAC, BAC design

Time table Ø SDC repair、test Ø STOF test Ø SP 0, SAC, BAC design