ELOG DESPEC

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

DESPEC

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Entry time:

Sat Apr 2 10:42:49 2022

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Subject*:

11.10 Found aida08 not running - merger/TapeServer stalled

Restart required power cycle of all FEE64s
*all* ADC calibrations failed during system wide checks it was necessary to use FADC align &amp; control (act on all FEE64 modules selected) to calibrate - first pass 
12/16 calibrated, successive individual re-calibrations calibrated remaining FEE64s

ASIC settings 2021Apr29-13-16-00
 slow comparator 0x2f

BNC PB-5
amplitude 1.0V
attenuation x1
polarity +
tail pulse
tau_d 1ms
rate 25Hz

Attachments 1-4 1.8.W n+n spectra 20us, 200us, 2ms, 20ms FSR
Attachments 5-8 1.8.W p+n spectra 20ms, 2ms, 200us, 20us FSR

Attachment 9 per FEE64 1.8.L spectra n+n strips
 aida04 pulser peak width 387 ch FWHM
Attachment 10 per FEE64 1.8.L spectra p+n strips
 aida10 pulser peak width 93 ch FWHM

Attachment 11 per FEE64 Rate spectra

Attachments 12-15 all system wide checks OK
Attachment 16 ADC data item stats
Attachment 17 FEE64 temps OK
Attachment 18 DSSSD bias & leakage currents OK

15.45 check of ASIC settings cf. https://www2.ph.ed.ac.uk/~td/AIDA/Information/Default%20AIDA%20ASIC%20Parameters.txt

Differences from default AIDA ASIC parameters
---------------------------------------------

Input Polarity
Offset Title                                Positive   Negative            Notes

12     slow comparator threshold            0x2f->0xa                     100keV nominal
 
14     fast comparator threshold HEC        0xf->0x02                     200MeV nominal
15     fast comparator threshold LEC/MEC    0xf->0xff                     > LEC/MEC nominal FSR

18     preAmp reference                     0xb2       0x20->0x30

21     Ibias LF feedback                    0x08       0xb->0xf

26     diode link threshold                 0xca->0xbf 0x11->0x23         decrease switch threshold

(front) p+n junction strips - positive input polarity
(back) n+n ohmic strips - negative input polarity

All looks OK - variations from default settings are those used at RIKEN

16:45 FEE64 adaptor PCB config

LK1 LK2 LK3 LK4
p+n n/c o   *   o
n+n o   o   n/c o

o   = jumper fitted
n/c = jumper not fitted

*   = top, middle FEE64s - n+n bias ring ground for Si wafer #2
      bottom, middle FEE64s - DSSSD PCB gnd

DSSSD#1 & #2 bias via standard coaxial cable to top p+n FEE64 adaptor PCBs

17.05 aida09 or aida13 cable braid not secured to ground - cable tag dia too large - now sandwiched between correctly sized cable tags 
      no obvious difference to adc data item rates

17.20 LK1 removed for all n+n PCBs
      attachment 19 - adc data item stats

18.55 LK2/LK4 removed for all n+n PCBs
      attachment 20 - adc data item stats

19.10 power cycle FEE64s
      attachment 21 - adc data item stats

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