Question 3 The proponents should show more details about the modification of the detector system to be built in P42 Answers 3-1. Liquid-Hydrogen Target 3-2. TPC Modifications 3-3. Two-particle Trigger

3-1. Liquid Hydrogen Target Basic design done with S. Ishimoto (KEK) Fit to the TPC target holder of 8cm f cylinder Reuse cryostat system of liquid-H target for E19 (penta-quark search) Need to construct newly Cryostat cylinder Vacuum cylinder Liquid-H cylinder Construction 1-2 M yen, 2 months Cryostat cylinder Vacuum cylinder Liquid-H cylinder

Liquid Hydrogen Target Minimize material Vacuum cylinder t=1mm CFRP (carbon fiber) conductor t=0.3mm Kapton Insulation to field strips Liquid-H cylinder t=0.4 mm PET used in E19 successfully Total thickness 0.28 gcm-2 radiation length ~0.7%

3-2. TPC Modifications E42 TPC P45 TPC Field strips Field cage Gas vessel Cathode GEM pad 560 670 300 50f 370 640f 143 Gating grid Beam level 520f 10 Target holder Field strips Field cage Gas vessel Cathode GEM pad 560 670 300 80f 370 640f 143 Gating grid Beam level 520f 10 Target holder Modifications for target diameter 50(E42)→80mmf (P45) To be replaced for P45 Gas vessel Field cage Target holder Share with E42 Gating Grid GEM Pad plane Electronics Electric Potential Calculations

Electric potential calculations 2-d calculation Gas vessel Field cage -13kV at maximum Target holder Double layer field strips dE/E < 0.1% in the almost whole active volume Prototype test for E42 at Pusan Univ. in Jan-Feb. 2013 2.5 mm pitch 2 mm width

3-3. Two-Particle Trigger Details are shown in answers to Questions 2 and 4 A pion (p+ or p-) beam with hits in 2 of 32 scintillators No K+ spectrometer trigger in E42 is required p- n p- p+

Backup

TPC prototype in Pusan Univ. Real drift length (55cm) Smaller pad area (10cmx10cm) Complete in early Feb. 2013 Lab test in Feb 2013 B-field test at J-PARC in Feb-Mar 2013

Costs Hydrogen Target ~ 2M yen TPC modifications ~ 3 M yen PMTs for Hodoscope 3-a. Normal PMT w/ magnetic shield ~ 4~10 M yen (depends on available PMTs from E03/07) 3-b. fine mesh PMT ~ 23 M yen Total cost 9~28 M yen to be shared with JAEA Kakenhi and Ohio (and other institutes)

Pad configuration Inner layer 2.1~2.7x9mm2 #plane=10 Outer layer 520 215.39 Inner layer 2.1~2.7x9mm2 #plane=10 Outer layer 2.3~2.4x12.5mm2 #plane=22 Total #pad 5768 Horizontal position resolution at B=1T <300mm At drift length>10cm

Mapping of pads to ASIC boards Colored pad group→1 AsAd 1 pad layer →1 AGET (ASIC) chip Symmetric w.r.t. the beam axis #AsAd = 28 #channel=7168 (#pad = 5768)

GEM configuration 500 Hit distribution (GEANT) 500 150 250 250 ・4 GEM (250mmx250mm) ・3-layer GEM structure 50mm + 50mm +100mm 500 Hit distribution (GEANT) Target position 500 150 250 Electrode division 12.5 mm width (20 div.) 1 sheet 41mm width（6 div.3 sheets ・Suppress discharge rate ・Minimize acceptance reduction in case an electrode is short-circuited 250

Potential configuration -13059.5 V 5500mm E=180V/cm Drift region Field strips Gating-grid Wires -3159.5 V 50mmf (Beryllium-Copper wire) Wire pitch = 1mm 4 mm E=180V/cm GEM1(50mm) -3087.5 V -2762.5 V 2 mm GEM2(50mm) -2112.5 V -1787.5 V 2 mm GEM3(100mm) -1137.5 V -650 V 2 mm Pad plane 0V

Field cage: Structure & materials A field cage for a TPC prototype The KPS Meeting, PyeongChang, 2012 Andrey Ni, PNU Field cage: Structure & materials The field shaping strips have a pitch of 2.5 mm and are intersected by 0.5 gaps. Mirror strips have the same parameters and displaced by half of a pitch. 10/25/2012 KPS meeting, PyeongChang 14

Electric field strips & mirror strips design A field cage for a TPC prototype The KPS Meeting, PyeongChang, 2012 Andrey Ni, PNU Electric field strips & mirror strips design 10/25/2012 KPS meeting, PyeongChang 15

Circuit plain for the connection of the field strips A field cage for a TPC prototype The KPS Meeting, PyeongChang, 2012 Andrey Ni, PNU Circuit plain for the connection of the field strips 10/25/2012 KPS meeting, PyeongChang 16

SC Helmholtz magnet Maxwell 3D calculation by Sung-Hyun Kim Bump Coil + Long bobbin : L-shaped SC coil Coil

y(cm) Bx Bz By Deviation (%) -30 -4.73E-03 -2.30E-03 -1.29E+00 3.3 -20 -3.09E-03 -3.92E-04 -1.35E+00 1.2 -10 -2.81E-03 1.05E-03 -1.80E-03 1.72E-03 -1.33E+00 0.1 +10 -3.19E-04 2.82E-03 +20 1.62E-04 6.02E-03 -1.32E+00 1.0 +30 2.54E-03 9.86E-03 -1.25E+00 5.9