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 11:17:03 2025
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> 00.55 Bias and leakage currents ok (attachments 1+2). > Temps ok (attachment 3). > > 01.40 DAQ starts (RIBF03R1 - Run R1) > > Pulser walkthrough > > BNC PB_4 amplituides 90,000 - 10,000 @ 10,000 step > x5 attenuator IN > frequency 250Hz range > t_r 50ns tau_d 50us > polarity -, tail pulse, delay MIN > > 01.55 Ambient temperature +24.8 deg C, d.p. -2.2 deg C, RH 16.6% > > 02.05 DAQ starts (RIBF03R1 - Run R2) > > Pulser walkthrough - same settings as above. > > BNC PB_4 amplitudes 14,000 - 2,000 @ 2,000 step > > 02.48 Run R3 started. > Pulser off. Background run. > > 15cm Pb wall removed > > 6mm Pb degrader installed between MUSIC 1 & 2 > variable degrader 1mm, 0.5mm & 0.3mm W + 1mm Al attached to each W sheet. > > 04.14 Noticed R3 stopped > > 05.40 Difficulty starting DAQ > 'want first SYNC' from merger > lost contact with nnaida19 - restarting merger > TclHttpd server on nnrpi1 crashed - restarted remotely > unable to power cycle - need to check fuses when next obtain access > whilst waiting boot aidas1 > > F11 rate c. 450Hz > AIDA veto plastic c. 3200Hz > > 07.30 R7 started with beam. > > 07.38 Beam stopped. > R7 continues. > > 08.12 Beam returned to F11. > File R7_9 > > 08.50 Beam stopped. > Start of R7_17. > Using implantdecay.f saw no HEC events in any DSSD. Removed 2mm of Pb degrader. > We re-insert all the variable Al degraders (for now) for safety. We can remove them again when the beam > comes back, as necessary. > Secondary beam current expected to remain at ~50cps. > Now no beam for ~1hr. > > 10.15 Beam comes back > There was a minor delay to get the beam back from some accelerator issue (SRQ issue I am told) > F11 plastic rate is about 10 cps, still I can see nothing in AIDA low gain > Main exp. team confirms several 40Mg events within minutes, and makes jokes about old Nature paper with 10 days of > data to do that. > > 10.25 Trying to find AIDA's implants, using MIDAS Sort in online mode > Removed the variable degraders, one-by-one. Still nothing? (this is now circa file R7_36) > Is there a possibility that the "low gain" setting of the ASIC is too high energy for something like 40Mg? > We try to check the implant rate with the AIDA veto plastic > During this time, we moved degraders in and out, several times, watching the oscilloscope and visual scalers by > video link in F11 > > 10.39 We check some scalers of the dE before AIDA (including F11 x plastic behind AIDA) > We can see a reasonable effect as expected for these detector count rates > The count rate never exceeds about 50 to 60 cps at maximum for dE > I don't trust MIDAS Sort in online mode > it is known to show factor 10 or less of the real rate, previously) > Check the data file R7_37 -> may show 1 to 2 Hz > We should decrease the low gain (heavy ion) threshold or dynamic range for the ASICs? > But DK is not an expert of that, and doesn't want to cause AIDA to cease functionality... > > 11.03 Checking runs later than R7_37 (i.e. _38 to _42) > Never see anything. R7_37 must have been taken with some amount of degraders in > We surmise that the ions are mostly punching through AIDA, owing to low Z. > > 11.05 We put in the 0.5 W + 1 mm Al degrader back, to see if we can get back the condition of _37... > R7_44 after a short delay should have this condition. > There can be 1 cps or something, though with small statistics it is hard to say... > It seems to be definitely non-zero though, compared to some runs like _38 to _42 > > 11.10 Add the 1.0 W + 1mm Al (with the 0.5 W and 1 mm Al) degrader > R7_45 begins ~400 MB before this time. > We can see some kinds of definite hit events with low stats (1 to 2 Hz in several detectors in some data blocks) > > It seems to be, if all degraders are out, that the beam punches through AIDA, and dE is below the thresholds > Of course, the count rate at F11 is only 10 cps, so we cannot conclude much with strong confidence... > > 11.17 Remove all variable degraders again (near halfway point of R7_46) > We need a decent LISE++ file to get a clue of where these ions are stopping...! > > 11.42 Beam is stopped because one of the cyclotron RF systems is down. > This occurs around the middle of file R7_50 > > 12.40 Still waiting for beam. I try a more definitive analysis of R7_45 > > Partial disk analysis of file R7_45: > > First part of data look like this: > * DSSSD # 1 count: 4 old count: 2 dt: 1.06 s HEC rate: 1.89 Hz > * DSSSD # 2 count: 1 old count: 0 dt: 1.06 s HEC rate: 0.94 Hz > * DSSSD # 3 count: 0 old count: 0 dt: 1.06 s HEC rate: 0.00 Hz > * DSSSD # 4 count: 0 old count: 0 dt: 1.06 s HEC rate: 0.00 Hz > * DSSSD # 5 count: 0 old count: 0 dt: 1.06 s HEC rate: 0.00 Hz > * DSSSD # 6 count: 10 old count: 10 dt: 1.06 s HEC rate: 0.00 Hz > > Notice that we get 10 total counts in DSSD#6, and practically 0 in any other layer (2 in DSSD#1) > > Now, as the analysis progresses, we do not increase the counts in DSSD#6, but we start to see events in other layers > * DSSSD # 1 count: 128 old count: 128 dt: 343.81 s HEC rate: 0.37 Hz > * DSSSD # 2 count: 115 old count: 115 dt: 343.81 s HEC rate: 0.33 Hz > * DSSSD # 3 count: 91 old count: 90 dt: 343.81 s HEC rate: 0.26 Hz > * DSSSD # 4 count: 41 old count: 40 dt: 343.81 s HEC rate: 0.12 Hz > * DSSSD # 5 count: 13 old count: 13 dt: 343.81 s HEC rate: 0.04 Hz > * DSSSD # 6 count: 12 old count: 12 dt: 343.81 s HEC rate: 0.03 Hz > > * ENTRY finish ends > > > Notice how only 12 counts in DSSD#6 (two new counts) but 128 counts in DSSD#1 (126 new counts). > > We can conclude that with 3 mm Pb (fixed), and 0.5 mm W and 1.0 mm Al, some of the beam is stopping in DSSD #6, and mostly > punches through. > Then, when 1.0 mm W and 1.0 mm Al are added, we shift the implantation to the beginning of AIDA (or some in the air > before AIDA). > So, we should try the 1 mm W (+1 mm Al) and 0.3 mm W (+1 mm Al) once the beam returns. > > 13.34 Stop run 7. > Change the medium/low energy selection on ASIC control from 0x0 to 0x1 (from low to medium energy mode) > (Already, the high energy setting is 0x2 and we cannot decrease it) > Start run 8. It looks okay, though of course now data rate becomes much smaller. > > 13.36 Beam is now on again. F11 rate has decreased 1 order of magnitude (now it is 0 to 2 Hz) > > 14.00 As expected, data rate becomes quite low, as the low energy mode has typically many events (10kHz or so) > But now we don't see anything in the high energy mode as before > 3 mm Pb remains in, and variable degraders are all out (mistake...we meant for some to be in) > Strange! But the beam at F11 does not seem to be the same rate as before the cyclotron issues... > Realized that someone was checking the beam at an earlier focal plane and that F11 has no beam... > (Post-dated note: forgot to hit "Start ASIC Readout" --- duh oops. > RUN 8 IS JUNK, AS NO ASIC READOUT BY USER ERROR (DK) > > 14.12 Stop run 8. Change the medium energy mode back to low energy mode of all ASICs. Restart as run 9. > But the merger data links don't alternate colors when I reload the merger screen. Is it bad? > Data rate is still very low, but that doesn't make much sense. > Okay, now I start ASIC Readout! Woohoo! > But it seems some magnetic dipole of BigRIPS must have an improper setting, explaining the 1 cps rate at F11... > > 15.33 Bias and leakage currents OK (attachments 9 & 10). > FEE64 temperatures OK (attachment 11). > > > 15.40 SRIM 2013 > > 145MeV/u (5800MeV) 40Mg + 3mm Pb > sigma 0.55 deg > ang X (str) 0.90 deg > assume Pb - DSSSD distance c. 2m => 2000 x tan(0.55 deg) ~ 17mm rms > consider reducing Pb - DSSSD distance Encoding**: HTML ELCode plain Suppress Email notification

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