1. 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

2. 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

3. 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%

4. 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

5. 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

6. 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+

7. Backup

8. 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

9. 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 ~28 M yen
to be shared with JAEA Kakenhi and Ohio (and other institutes)

10. 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

11. 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)

12. 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

13. Potential configurationV
5500mm
E=180V/cm
Drift region
Field strips
Gating-grid Wires V
50mmf (Beryllium-Copper wire)
Wire pitch = 1mm
4 mm
E=180V/cm
GEM1(50mm) V V
2 mm
GEM2(50mm) V V
2 mm
GEM3(100mm) V
-650 V
2 mm
Pad plane 0V

14. 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

15. 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

16. 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

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

18. 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