Faraday Cup

Adone Faraday cup
dimensions
copper shielding

Current to charge conversion with QDC Caen V965:

After having performed a pedestal subtracion, the ADC value is converted to charge with this formula:

ADC(pede sub)/4095*FS(ch)= Q [pC]

where:

• ADC(pede sub) = pedestal subtracted ADC value
• FS(ch)= range in [pC] of the selected dual range channel (100pC or 900pC, new version of V965)
• Q is the charge expressed in pC

Current to charge conversion with One electron:

Put on peak the value of

• 6.006 for 900pC
• 54.054 for 100pC

and validate,

the #ele control will measure the value of total integrated charge in unit of 10^7 electrons

Current to charge conversion with oscilloscope:

1. - Integrated Charge with measure reference bars (measure outputted by scope)= C [pV*s]
2. - Pedestal = F[pV*s] (same as signal measure, triggered with DHSTB001 in stby mode)
3. - Internal resistance = R[Ohm]
4. - Bergoz monitor calibration ⇒ Q(beam)/Q(out) @ 50 Ohm
5. - Bunch pulse width = dt [ns]

Formula to obtain iduced charge on WCM via scope:

Q[pC]=[(C-F)/R]

Formula to obtain mean current from single bunches (To be compared with LINAC WCMTM001 in order to measure transport efficiency):

I[mA]=  { (C[pVs]-F[pVs]) /50[Ohm]}/dt[ns]