AIDA
GELINA
BRIKEN
nToF
CRIB
ISOLDE
CIRCE
nTOFCapture
DESPEC
DTAS
EDI_PSA
179Ta
CARME
StellarModelling
DCF
K40
nToF
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Entry time:
Fri Mar 28 20:47:48 2025
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> > Observe c. 2mV p to p noise with DSO ( Z_in = 50 Ohm ) c. 60us period with HF structure. DSO connected to junction box via 34-way IDC - 16x Lemo-00 adaptor. > > Origin of noise upstream of 4x34-way to 8x16-way Junction Box. Not microphonics from Edwards RV5 Rotary Pump. > No change observed with simple ground connections between NIM bin/+/-15V PSU/Junction Box and MSL type W1 preamplifier units/vacuum chamber/support assembly. > > > Estimate of electronic noise > > Pulser BNC PB-5 > > Amplitude 0.5V > Attenuation x1 > Decay time 1ms > Frequency 50Hz > > Preamplifier RAL108 > Output impedance 100 Ohm > Sensitivity 20mV/MeV ( into high Z load ), 6.7mV/MeV ( into 50 Ohm load ) > > Amplifier EG&G Ortec 571 > Input terminated by 50 Ohm > Gain x1 (internal) x 1.0 (fine gain) x 50 (coarse gain ) = 50 > Shaping time 0.5us > > MCA Amptek 8000D > Input FSR 10V > 12 bit ADC > > > Nominal gain = 6.7mV/MeV x 50 = 335mV/MeV > > 12 bit ADC input FSR = 10V / 0.335V/MeV = 29.85MeV FSR or 7.3keV/channel > > > dE p+n junction strip # 4 ( of 0-15 ) > > pulser peak centroid = 799.8 ch > pulser peak width = 7.8 ch FWHM = 57 keV FWHM > > > E p+n junction strip # 4 ( of 0-15 ) > > pulser peak centroid = 864.8ch > pulser peak width = 3.5 ch FWHM = 26 keV FWHM > > > E n+n Ohmic strip # 4 ( of 0-15 ) > > pulser peak centroid = 913.0 ch > pulser peak width = 5.3 ch FWHM = 39 keV FWHM > > > Noise estimates are probably accurate to c. 10% level.
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