S2 — VTPC23

FRS Home Page - – S2 – Pictures – Drawings – Cable Connections – TPC Electronics – Memo for preparation before beam time

Present Configuration (as of 2020/October/22)

- Installed in the air section of S2.
- Gap (vertical) = 6 cm (This means -2400 V for the drift field voltage)
- Normal orientation. (Grid is behind TPC).
- Calibration positions should be x = -12, 0, +12 mm and y = -6, 0, +6 mm, (note that internal plastic blocck is ~ 22 mm thick)
- Maximum allowed HV: -2400 V (drift), +1100 V (anode), -700 V (calibration, PMT).
For heavy ions, anode and PMT voltages should be much lower than the maximum values.
- Picture

Status during previous beam time

2021/Feb/15-Feb/22 (12C beam, S533/BARB + EXPERT test)

- HV(anode) = +1050V, HV(drift) = -2400V, HV(grid-pmt) = -700V
- Analog raw signal around 150--200 mV. Vth(tpc module) around 60--70 mV
- Calibration file is /d/land4/sec/s533/tpc23_calib_0025.lmd (Logbook p41-43)
- Parameter sets used during experiment is found here.

2020/Apr/08--Apr/27 (Pb beam, S468, S482, S481)

- Applied voltages: anode HV = +580 V, drift = -2400 V, grid-PMT = -530 V.

2020/Feb/28--Mar/16 (Xe beam, S474, S459, S480)

- Applied voltages: anode HV = +600 V, drift = -2400 V, grid-PMT = -500 V
- Issue: 1st anode had very week signal in TDC. This could be due to amplifier or detector itself.
- Calibration pictures and parameters (with mask trigger) in run0112 (Feb.29)
- To have consistent track from all 4 TPCs, one could add the values on page 5 of this memo to the grid position
- Y position is now caculated properly even with different trigger (time reference is subtracted).

2020/Feb/20--Feb/26 (Kr beam, Ca fragments, Cave-C S467)

- Applied voltages: anode HV = +700 V, drift HV = -2400V, Fiber-PMT = -500 V
- Issue: 1st anode had very week signal in TDC. This could be due to amplifier or detector itself.
- Calibration pictures and parameters (with mask trigger) in run0087
- Y position with other triggers (particularly SC81) should be calculated by taking into account time references.

-- NisanYaprakBenal - 2026-10-30