ELOG AIDA

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

AIDA

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Entry time:	Sat Mar 29 11:18:33 2025
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> > There appears to be significant common mode noise on the output of the > CAEN N1419 4 Ch Reversible 500 V/200 渙 NIM HV Power Supply Module (USB) > - the specification quotes 'Max Ripple smaller than < 5mVpp'. We configure > the CAEN N1419 outputs as floating wrt NIM module/crate chassis. > > For example, attachment 1, shows the output of module #2 (Addr 01) channel #3 > (unused channel) set to 10V (leakage current 0.030uA) - core (Ch 1)/braid (Ch 2). > Tektronix 3034C channels 1 & 2 are both set ac/1M. > > Attachment 2 shows math function Ch 1 - Ch 2 (50mV/division cf. 200mV/division > for Ch 1 and Ch 2) > > Attachment 3 shows CAEN N1419 #2 settings > > Attachment 4 per attachments 1 & 2 except the cables from channels 0 and 1 > of CAEN N1419 #2 have been disconnected from the NIM module. The structure of > the common mode noise changes but its amplitude remains significant. This > presumably indicates that there are other sources of common mode noise in > addition to that observed at the output of the CAEN N1419 HV outputs. > > Attachments 5 & 6 show the NIM crate front panel +6V output wrt ground > for the lower (NIM Bin type REPIC, BNC PB-4, Ortec 433, 2x MACB, 2x CAEN N1419, > 1x CAEN 1419B) and upper (NIM Bin type OKEN, 9x MACB) AIDA NIM bins respectively. > All +/-24V, +/-12V and +/-6V front panel outputs show the same noise structure. > > Attachment 7 shows equivalent of attachment 6 but using Tektronix DPO3054 > which can display FFT. > > Update ----------------------------------------- > Tested the CAEN HV supply in T9 using the same method and observed similar results. > > With help from Mos Kogimtzis a better method of measuring the HV noise was used. > The co-ax from the isolated output of the HV module was connected to one input of the 'scope. HV set to 1V. > Thus the screen of the HV signal is grounded at the 'scope amplifier input. This nearer to how the HV is used with a detector. > The single signal input channel was set to DC 1MR with an offset of 1V. > The 'scope can now display at 4mV/division. > The peak/peak was less than 5mV.See attachment 8 slide 1 > > There are features at both high and low frequency, attachments slides 2 and 3. NB 1mV/division. > > If a differential measurement is required then a suitable cable with a shielded twisted pair is needed. > > Update #2 ----------------------------------------- > Moved the AIDA T9 HV supply to a CAEN NIM bin. Newly purchased this year. > This is the only module in the bin. > Used the simple method of noise measuring as before with the same cables and 'scope. > Attachment 9 shows there is a different type of noise. Not regular like attachment 8 but more random and larger. > > The HV is set to 1V. > > Further investigation will be carried out using AC coupling and HV set to 50V. Encoding: HTML ELCode plain Suppress Email notification

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