Lead Glass → Cherenkov

From the former OPAL electromagnetic calorimeter

Referred measuring System
Caen V965 - CH4 900pC (old Type)
Caen N625 - CH2 @ -7mV bias

N=184.85*(x)^7.705*Ebeam\E0
N = single particle value [adc unit, pedestal subtracted]
x = V/1200 [V]
V= Voltage on CALO (Minimum Voltage 450V)
Ebeam = Energy beam [MeV]
E0 = 447 [MeV]

TABLE @ 447 MeV
Last calibration @450MeV 20220505

Oscilloscope to Multiplicity calibration
To recover multiplicity by your own measurement system with our CALOBTF1 signal, follow these steps:

• Usually we will refer our measurement with our QDC Caen V965 (old Type, 800[pC] full scale in 12bit, output is in ADC values)
• acquire the signal in time domain
• give an integration time about 200[ns], centred on Beam signal (typically CALOBTF1 signal Tr=8[ns], Tf=20[ns]) to pick up best baseline
• measure integrate pedestal without beam signal (P). Oscilloscope will give you values in [V*s], to get value in [pC], divide by your input impedance. Usually P=70/4096x900 [adc/adc*pC] = 13.7 [pC]
• measure the integrated gate signal (GS) and removing pedestal value and get your signal (S) then [mV*ns/Ohm]=[pC]
• Multiplicity (M) is this value normalized in our ADC scale value, divided by N , single particle value (see table on top for CALOBTF1, voltage and beam energy dependant)

S=(GS-P)/(50)= [V*s/Ohm]
M=S/900E-12*4096/N = [C*ADC/C/ADC]

CALO as BACKGROUND gamma detector for HIGH INTENSITY operation on N@BTF
We can use CALOBTF1 as background gamma detector to discover the upper limit of gamma to prevent the safety sistem to trips.
We put CALOBTF1 in the bent middle line at 3.8 meters from exit bent pipe with 500V supply
Normal operation means up to 20mV peak to peak signal, if above the safety trips