CALOBTF2

Lead Glass → Cherenkov

From the former OPAL electromagnetic calorimeter

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

N=[239.7*(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 = 450 [MeV]

TABLE @ 450 MeV
Last calibration @450MeV 20220505

V	N
1300	444.14
1200	239.7
1100	122.6
1000	58.83
900	26.122
800	10.540
700	3.768
600	1.1496
500	0.28288

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

Usually we will refer our measurement with our QDC Caen V965 (new type, 900[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 CALOBTF 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 CALOBTF, voltage and beam energy dependant)

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

CALO as BACKGROUND gamma detector for HIGH INTENSITY operation on N@BTF
We can use CALOBTF as background gamma detector to discover the upper limit of gamma to prevent the safety sistem to trips.
We put CALOBTF 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