ELOG DESPEC

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

DESPEC

Fields marked with * are required

Entry time:

Sun Jun 19 12:36:10 2022

Author*:

Subject*:

Yesterday the sum/inverter was found to be a considerable source of noise in the system.

Plugging it into an oscilloscope this morning it was clear there was a Vpp 17mv 60kHz sin wave in its signal - attachment 1 yellow trace

Moved the inverter to a crate in the messheute and did not see same behaviour. This time see Vpp 5mV and a ~265Hz wave that looks much less clean. - attachment 2 yellow

Put inverter back in CAEN crate in S4 and confirm similar behavior.

Move CAEN crate to new mains port, same behaviour

Move CAEN crate to AC voltage stabiliser, same behaviour

Remove module one by one from CAEN crate.
Removing BIAS supply - No change
Remove Pulser - No change
Remove right most MACB - No change
Remove second right most MACB - Signal disappears  - attachment 3 blue trace
Remove second right most MACB from the rack entirely
Put right most MACB back - Signal comes back - attachment 4 blue trace
Test MACB with and without HDMI connectors connected signal remains
Remove rightmost MACB from the rack - Signal disappears

Put pulser and bias back - Signal does not return
Signal also doesn't return when ramping up bias or running the pulser
Power DAQ up - No change in performance from yesterday with inverter removed.

MACB and Inverter don't share any voltages on NIM:
MACB +-6V and Gnd
Inverter +-24V and Gnd

CAEN Crate does not have any easily accessible monitoring points. Anyone have any ideas?

MACBs and inverter checked on another crate - no signal

Inverter put back in CAEN crate and no noise observed on scope.
With waveforms disabled am able to get <100kHz on all FEEs with the pulser connected

Tested adding bias filters - No change

15:30 Nic realised that one of the mains boxes is labelled measurement network so we connect the AIDA PSU to this via the ac stabiliser
      We get ok stats even with waveforms on at 0xa- attachment 5

Waveforms still have the 100kHz oscillation in them though attachments 6 and 7

Without waveforms we get similar performance to before the switch to the new mains - attachment 8

15:56 Move CAEN NIM crate across to this mains network
      300+kHz on all FEEs with waveforms on. Can recover waveform off performance though

16:01 Place CAEN NIM crate back onto platform mains but don't recover the ealier rates with waveform. Everything still around 300kHz.

17:43 Current best settings are waveforms off and we can run at 0xa on all FEEs - attachment 9

Encoding: HTML ELCode plain
Suppress Email notification Resubmit as new entry

Attachment 1:

1.jpg Original size: 166x221

Attachment 2:

2.jpg Original size: 1175x881

Attachment 3:

3.jpg Original size: 661x881

Attachment 4:

4.jpg Original size: 1175x881

Attachment 5:

220618_1753_stats_no_waveform.png Original size: 1920x420

Attachment 6:

Drop attachments here...

ELOG V3.1.4-unknown