ELOG nToF

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

nToF

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Entry time:

Thu Aug 10 16:11:57 2023

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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