1/t tail cancellation (Double PZC network)
s
1st Pole-Zero Cancellation Inverting polarity of output signal Change time constant - 47 ns -> 4.7 ns
Pre-Amplifier
Prototype Amplifier for the New BHCV
Development of Amplifier and Shaper for High-Rate MWPC I. Kamiji1, N. Sasao2, T. Nomura3, H. Nanjo1, N. Kawasaki1, D. Naito1, Y. Maeda1, S. Seki1, K. Nakagiri1
1Dep. of Phys., Kyoto Univ., 2Dep. of Phys., Okayama Univ., 3KEK
C0
1pF
51Ohm
R0
C1
1pF
R2
47kOhm
R6
6.8kOhm
4.7kOhm
R7
C4
10pF
R8
200OhmR9
200Ohm
R5
1kOhmC3
4.7pF
R3
100R4
910
C2
47pFR10
13kOhm
22kOhm
R11
C5
47pF
R12
200OhmR13
200Ohm
U1U2 U3
U4 R14
5.1kOhm
1kOhm
R15
C6
4.7pF
R16
220OhmR17
100Ohm
U5
INPUT
TestOutput
Schematic Diagram * PZC = Pole-Zero Cancellation * Ux (x = 1 – 5): ADA4817 (Op-Amp)
Output signal of MWPC
Double Pole-Zero Cancellation Network
Goal of the KOTO Experiment Discovery of
- Direct CP violation -suppressed in the SM: BR = 2.4 x 10-11 - Small theoretical uncertainty (2%)
→ Sensitive to new physics beyond the SM
KL p0
Particles beyond the SM can contribute via the loop
Target: 2g (p0→2g) on EMCal + “Nothing Else” “Nothing” is assured by hermetic veto detectors
KL
2g p0
Veto Detectors
2n (through away)
BHCV
EM Calorimeter
J-PARC E14 (KOTO) Experiment
BHCV (Beam Hole Charged Veto) - In-beam veto detector for charged particles at the downstream part of the KOTO detectors - Incident rate of in-beam neutral particles (g and neutron) is up to a few GHz → Signal loss due to fake vetoes
p0
KL
2g
p+
p-
BHCV
30
0 m
m
300 mm
2 cm gang/ch 2mm
Au-W anode wire (φ50 mm) Side Front
zoom
1.6 mm Gas Volume BHCV Upgrade
3mm thick MWPC
Performance Test w/ Single-Channel Prototype of the New BHCV Effect of 1/t tail Cancellation
Pulse Width: 100 ns
Requirement & Solution ✓ Good S/N for ¼ MIP peak events -> Charge Sensitive Amp. w/ Low Noise Op-amp
✓ Capability for high-rate operation up to 800 kHz w/o baseline shift -> 1/t tail Cancellation Circuit
A1=0.79 a1=1.6
A2=0.185 a2=13.5
A3=0.024 a3=113
Pulse Width: O(10 ms) -> 100 ns
AMP
90Sr Plastic Scintillator (trigger)
Prototype BHCV to oscilloscope
Side View
Wires (x13)
2 cm
30 cm Top View
Single Channel Prototype * Read only inner 11 wires * HV: 3000 V
connection
Amp. in shield case
Peak Height Distribution
S/N wrt ¼ MIP peak 46mV/5mV = 9.2
* Normalized for peak height
b-ray
MIP Peak: 184 mV
Charge Gain 7.6 V/pC Charge Gain (Pre-Amp) 680 mV/pC
Std. Dev. of Output Noise 5 mV
Equivalent Noise Charge 4000 e
Basic Performance
change the time constant: - at0 -> 4.7 ns (time constant of 1st PZC)
Charge sensitive amplifier - Time constant: 47 ns Low noise, high speed op-amp - 4nV/√Hz, 2.5fA/√Hz - Gain-Bandwidth: 410 MHz
Additional PZC
Requirement for BHCV - Efficiency: 99.5% - High rate operation
The prototype amplifier and shaper for high-rate MWPC have been developed
- Good S/N for ¼ MIP peak events - Narrow pulse width (100 ns)
Conclusion Next Steps: - Finalize multi-channel amp. and shaper - Install and Operate BHCV for KOTO
Efficiency of BHCV: 99.5% 800 kHz operation w/ little baseline shift
Measurement Measurement
Calculation
- Gas: CF4:n-Pentane (55:45) - Mean Energy Deposit: 1.4 keV - High Voltage: 3000 V - Capacitance: 50pF/ch - Hit Rate: 800kHz (Max.)
Ex.) KL → p+p-p0 background
Remaining tail: 1% of peak height & 400 ns width
Calculation
Remaining Tail
The test chamber is the same one shown in the poster No.P-603
Detail discussion -> poster No.P-603
are expected
Cancelled
