 Thu Jun 13 10:06:35 2024, Constantine, Peter, Lukas, Jonas, Dounia, Carsten, Accelerator, Suspected Beam Troubles (is it really 229-Thorium?)
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From experience, the lifetime of the beam in the storage ring should be on the order of magnitude of hours, however, we observer beam lifetimes of the order of 10ish minutes. This suggests either a beam loss mechanism, a totally wrong species or a combination of both.
Yesterday (Elog entry 46) it was verified that the main beam is indeed 229-Thorium in the ESR.
2024-06-13: After discussion (phone) with Markus the lifetimes are reasonable and are dominated by recombination in the cooler. |
Thu Jun 13 02:05:04 2024, Carsten, Accelerator, Short Lifetime at 100 mA 
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Lifetime still is short |
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Wed Jun 12 22:48:55 2024, Carsten, , Beam Halo
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The seamingly short live time reported in entry 53 is due to a halo from a different isotope (?). It can be scraped away from the outside. The 229Th89+ primary beam can be scaped away from the inside and the halo stays. There is some spacial headroom between the two components.
Scraping from the outside using GE02DS3HG @+6mm starts to scrape the halo in the south arc. Please note that the +6mm means that you move past central orbit (scraper starts from -130mm).
Using this scraper allows for using the particle detector behind the e-cooler (GE02DD2_G). Position PD south in event mode is -30mm (has to be verified with higher ion beam intensity and electron current for larger recombination rate=.
The primary 229Th89+ is touched from the inside with GE01DB2IG @+14mm (north arc).
Position of GE02DS3HG in event mode is +8mm.
Electron current in SC8 is increased from 100mA to 200mA for faster cooling at low energy in order to condition after deceleration and before scraping.
positions particle detectors and scrapers
NA position -30 activated
NI +28
SA -28
DS3HG +10 |
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Wed Jun 12 21:21:15 2024, Yuri, Detectors, NTCap started
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Fcenter - 244.6 MHz
BW - 10 MHz |
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Wed Jun 12 18:48:43 2024, Afternoon shift, Runs, First laser scans
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Time | Part. Det. Int | ESR-intensity | cooler-HV | LMD-DAQ1 Files | LMD-DAQ2 Files | scan range(nm) | number of positions | dwell time(s) | n loops | comments
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19:15 | 38257 | xx e x | 104416 | 10 | 21-23 | 550.1 - 550.9 | 201 | 2s | 8 | 40 SIS injections. Very short lifetime, further investigation is needed. preset_2024-06-12_19-08-23.mps
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20:22 | 53056 | xx e x | 104416 | 11 | 24-25 | 550.1 - 550.9 | 201 | 1s | 3 | 40 SIS injections. Only PDetector behing cooler, retracted by 8 mm. Still short lifetime.
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20:58 | 40500 | xx e x | 104416 | 12 | 26-26 | 550.1 - 550.9 | 201 | 1s | 2 | 40 SIS injections.
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Wed Jun 12 17:12:13 2024, Julian, Danyal, Rodolfo, Laser, Timing für 229Th89+
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We did the timing Ion-Beam Laser-beam time overlap.
The ion revolution frequency (and therefore the bunching frequency) is: 1.5429 MHz. |
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Wed Jun 12 12:12:44 2024, Konstantin Mohr, Julien Spahn, Jonas Koedel, Bernhard Maass, Accelerator, First Scraper Scan
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Thorium is in the ESR, we have time to check the beam position with the scrapers.
Beam Intensity in the ring 6E-5
Laser stabilization:
x1: -0.050
y1: -0.244
x2: 0.151
y2: -0.489
DS1VU: starting in negatives, touches beam at -0.1mm, beam gone at 0.5mm (laser gone)
due to betatron oscillation, vertical beam center is +0.5mm, beam diameter 1.2mm
DS1HA: starting in negatives, hf artifacts are gone at -25mm, touches beam at -17.2mm, beam gone at -16.4mm (laser gone)
DS1HA: starting in positives, hf artifacts are gone at +2mm, touches beam at -7.1mm, beam gone at -7.9mm
horizontal beam center is at -12.2mm, beam diameter 2.1mm (scraper is 8mm wide)
DS2VU: starting in negatives, touches beam at 0.4mm, beam gone at 1.0mm (laser gone)
due to betatron oscillation, vertical beam center is 1.0mm, beam diameter 1.2mm
DS2HA: starting in positives, hf artifacts are gone at 6mm, touches beam at -3.5mm, beam gone at -4.3mm (laser is scraped)
DS2HA: starting in negatives, hf artifacts are gone at -27mm, touches beam at -14.4mm, beam gone at -14.1mm (laser is scraped)
horizontal beam center is at -9.2mm, beam diameter 2.9mm (scraper is 8mm wide)
After the measurement of the ion beam position we superimposed the laser beam (see attachment 1). |
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Wed Jun 12 09:43:57 2024, Carsten, Accelerator, Stopped NTCAP at 9:43
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Setup at ESR is carried on - stopped the long-time NTCAP run from overnight, |
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Wed Jun 12 09:17:43 2024, Carsten, , Tests of background with ionization pumps on (from monday)
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On monday the ionization pumps were switch on to test the background, and if it is possible to run with the pumps switched on.
Results and comments, see below:
Later some data were recorded with DAQ1 to allow for a more thorough analysis - beam is 238U38+ at 401 MeV/u - file 0013
Please note the data of this file was recorded after the figures below were taken.
In short, we have switched off the the ionization pumps because the conclusion is somehow ambiguous. Background rates from real photons are considerably low at ~5Hz and 10Hz for the small-band PMTs (see figure), Yet, PMT south goes up to 350 Hz and sees a lot of photons from the plasma discharge. The few Hz of the small-band detector would be suppressed by the length of the ion bunch / full lenght of the ring. But what is not known is how much it would actually influence the local vacuum of the ring.
Semjon Strohmenger also checked that the valve to the turbos in front and behind the gas-jet is open (--yes). They are running the whole beam time.
I exchanged the prepump at a pocket located between gas-jet and VUV detection set-up. Here after baking a leak was found, and the pocket was pumped with an "old" prepump.
Vacumm in the pocket was ~1mBar. Installed a more powerful Edwards XDS i10. When we left ESR the pressure in the pocket was already at low 10^-2 mbar and still decreasing.
May be this helps to improve local pressure. |
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Wed Jun 12 01:51:51 2024, RuiJiu, David, Analysis, ID
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The preliminary identification has been thoroughly checked using the RionID software. We have confirmed that the identification is accurate.
Attached can be found the simulation file with each of the expected ions, their revolutions frequencies in the 125th harmonic and expected yield from the LISE file attached.
Also attached are some figures from RionID that highlight the region of interest for the 124th and 125th harmonics. The center frequency of the 245 MHz resonator is closer to the 124th harmonic for 229Th+89 which is located at 244.769 MHz.
If necessary, we can slightly shift the resonator curve to higher frequencies to fine-tune the signal-to-noise ratio for 229Th+89. |
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Tue Jun 11 23:46:06 2024, Carsten )))), Accelerator, ID
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----
The frequency of the primary beam 238U82+ at the injection:
Ucool = -360 V
Frev = 1.974647 MHz without bump
Frev=1.97387 MHz with bump
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ID:
246 MHz + kHz (+/- intensity) ID
521 +++ 238/92+
565 +. 230/89+
595 +++ 235/91+
642 +. 227/88+
670 +. 232/90+
693 +++ 237/92+ (strongest line)
721 +. 224/87+
744 ++. 229/89+ (our Th line)
767 ++. 234/91+
822 +. 226/88+
845 +. 231/90+
867 +. 236/92+
901 - 223/87+
922 +. 228/89+
942 +. 233/91+
1001 +. 225/88+
1020 ++. 230/90+
1039 +. 235/92+
1100 +. 227/89+
1211 + <- far off |
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Tue Jun 11 22:59:06 2024, Carsten, Accelerator, Identification / NTCAP started
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ESR is set-up in most parts.We are trying to identify our 229Th89+. It is more cumbersome then exspected because of the thick target an d the according energy loss, the pattern has changed compared to the last beamtime.
Just started the NTCAP with center frequency 246,5 MHz, 10 MSamples/s and -25db.
Center frequency will later be changed back to about 244,5 Mhz.
Directory 06-11-22_55_15 (correct time stamp). |
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Tue Jun 11 21:38:35 2024, Julian, Imke, Rodolfo, Laser, Wavemeter HeNe long time stability
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The HeNe was running over night and the measured laser frequency of the wavemeter was logged, see picture.
A significant drift of around 300 MHz is visible during the night.
It is possible, that the laser lab got too cold during the night, as the pulsed laser was not running.
For now, we put the wavemeter in a thermoinsulator box... |
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Tue Jun 11 21:23:11 2024, Julian, Imke, General, How to read out voltage
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1.) If not already opened, open the Medusa Laser Control software, see picture:
2.) In the "view" submenu, choose "proteus status".
3.) At the bottom of the list, the K250 shows the scaled voltage. |
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Tue Jun 11 09:17:46 2024, Julien, Konstantin, Lukas, DAQ, Important commands (DAQ1)
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To connect to the DAQ1 pc, open a terminal and type:
ssh atplaser@r4l-41
Enter password for user atplaser (note that you're typing on an English keyboard).
To start MBS on DAQ1 go to folder mbsrun/E0052/DAQ1 via "cd mbsrun/E0052/DAQ1" and start mbs by typing "mbs". If you want to ensure that you are in the correct folder list the content of the folder by using "ls -l". You should see the list depicted in the second attachment.
Finally, to start the data acquisition (ensure that the 'medusa' is running on atppc023) use commands
@startup
sta ac
within the mbs prompt. You should see a similar result as in attachment 3. Particularly, note the important line
"-R4L-41 :read_meb :connected successfully to LabView Server. ".
A more detailed compilation of commands within mbs is given in Entry 10.
If one wants to observe the current acquisition, one must open a second terminal and establish another ssh-connection to R4l-41. The "rate" command will then show the incoming events on mbs (see attachment 4). If something went wrong you will see that the event-rate goes down. This might be an indication that the connection to medusa has crashed (see attachment 5). |
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Mon Jun 10 11:59:12 2024, Ruijiu Chen, Analysis, The ion identification of spectrum recorded on 2022
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The simulated frequency is given in simulation_result.out. The yield is calculated by LISE file. The LISE file is attached here also. |
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Mon Jun 10 09:17:38 2024, Carsten, DAQ, Updated Channel List
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Mon Jun 10 08:57:35 2024, Carsten/Konstantin, DAQ, Further Tests from Sunday 2024-06-09 - new voltages and tresholds for PMTs - testdata in files
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Voltages and thresholds increased for PMT Middle and North (in order to account for the ADC measurement in DAQ2
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PMT South ("braodband") ET9422 | 1500 V | thresh: 7
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PMT Middle ("smallband") ET9423 | 2650 V | thresh: 10
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PMT North ("smallband") ET9423 | 2650 V | thresh: 12
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Tests with laser
Thresholds adjusted for PD SO and PD NO.
Smaller adjustements in the analysis cdoe of DAQ1 (directory 229Th) to deal with the proper alignment of laser steps (Step-spectra). Seems to solved now.
DAQ rate/trigger rate DAQ1 - interference with Labview
DAQ1 can be started without connection to Labview server after some timeout (~ 1min) or so the usual trigger rtate of 200 Hz can be seen in mbs (via: "sh acq" command)
If the Labview server is closed, e.g. during the run or between to laser runs - the DAQ rate drops to 30 Hz only. Very likely MBS is busy trying to fetch data from the non existing Labiew server.
The problem can be solved by leaving closing the the DAQ (MBS not Go4...) and restarting mbs/DAQ, e.g. via @shutdown, leave mbs, resl, start mbs, Qstartup, start acq.
Of course, also Go4 needs to be restarted to establish a new connection to MBS.
The DAQ rate of DAQ1 should be regularly checked with sh acq !
Test data
DAQ1: 005.lmd
DAQ2: 010.lmd
both rubbish, partially adjustments of threshilds etc.
~2.7e6 ions (238U92+)
201 laser steps 550nm, 549nm, 50 shots per step
DAQ1: 006.lmd
DAQ2: 011.lmd/012.lmd
Threshold for PD SO not adjusted
restart
DAQ1: 007.lmd
DAQ2 013-017.lmd
same with few 10^5 ions:
DAQ1: 008.lmd
DAQ2: 018-020.lmd |
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Sun Jun 9 10:20:38 2024, Carsten/Danyal, Detectors, Recap from yesterdays work with test beam (Detectors / beam /DAQ)
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In the ESR we had thw whole day (saturday) a 400MeV/u bunched 238U92+ test beam (about 2 MHz). The RF signal is cabled as input to the DAQ (seperate post/entry).
Intensity is artificially reduced to a few 10^6 (with some tests alsodone at 10^5).
In all the tests the both particle detectors were moved in pus the empty pocket on the inside to mimick the background conditions during the run (aka no other isoopes, no other charge state, clearing of orbit fromdonw-charged ions.
Noise background
With the bunched beam all three PMTs and the channeltron show an ~20MHz "noise beat" below the actual signal that seems to be phase stable. The "noise train" is repeated with about 2 MHz (very likely the bunch revolution frequency). The amplitude of the noise is rather low and can be easily discriminated for the three PMTs, but not so easy for the channeltron, as the channeltron signal is more "continuous" and has no clear gap for the threshold.
A working hypothesis could be that Al mirrors or something similar act as pickup electrodes for the real beam.
2024-06-10: Correction : Signal is not "phase-stable" - and 200 kHz (wrong reading and triggering of scope)
Channeltron
The signal of the CT is rather small. In order to get the singal of the CT out of the noise it needed to be opreated at about 2600V. With an according threshold setting the CT sees a signal that is clearly from the beam and absent with "no-beam". The signal is 6-7 kHz even at the lowest intensitiies of ~10^5 ions in the ring. Worse, it doesn't show any bunch timing peak in the spctrum.
We decided that under these conditions the CT cannot be used during the 229Th beamtime.
PMTs
Voltages of the PMTs and thresholds of the CAEN CFD are adjusted with a bunched beam with an intensity of few 1 to 3*10^6 ions (and thus should be ok for lower intensities):
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PMT South ("braodband") ET9422 | 1500 V | thresh: 7
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PMT Middle ("smallband") ET9423 | 2550 V | thresh: 9
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PMT North ("smallband") ET9423 | 2600 V | thresh: 11
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Bunch signals in DAQ
Ion frequency (measured) used in DAQ1 in SetParameter.C: 1.9693 MHz, the divisiion factor is set to 88.
All three PMTs show very nice and small bunch-time signals with a very low background floor. Thresholds are adjusted to have at least "1CFD tick" extra margin.
The small-band PMTs have no-beam rates < 1Hz, PMT south < 10 Hz.
The clear visibility of the bunches on the small-band PMTs means, on the other hand, that we still have quite some background from collisions with the residual gas (albeit it seems to be lower that in the last beamtime, but no concrete (normalized) numbers are available. PMT North and Middle have about the same solid angle but PMT middle features the CaF2 window. The bunch singal rate of PMT middle is about twice the one of PMT north indicating that about half of the signal stems from hydrogen Ly-alpha (at 121.6 nm) that is cut-off by the CaF2-window (about 123 nm).
We should discuss a) if the vacuum can be further improved, e.g. using the turbo pump, b) if PMT north should get a CaF2 filter (not at the moment).
All these findings are for the 400 MeV/u 238U92+ beam and should be rechecked with decelerated 200 MeV/u beam.
For both DAQs data are accumulated with two data sets, the first at a a few 10^6 ions and the second at a few 10^5 ions:
files for run1 (mid int): 003.lmd (DAQ1), 006-006.lmd (DAQ2)
files for run2 (low int): xxx.lmd (DAQ1), yyy-yyy.lmd (DAQ2)
The timing signals can also be very nicely be seen in the 25 ps TDC of DAQ2.
DAQ2 records also th common Stop signal in the 25ps TDC. There are indications that the CS signal (derived from the bunch frequency) jitters. The discrimonation of the bunchsignal should be cheked.
In DAQ2 the thesholds and windows for Mesytec are not yet set properly, so thre is no ADC signal, and no "second" discriminated signal.
This is because the Mesytec MSFC16 module had to replaced by a different similar module but with non-ideal internal components. The module still needs ot be adjusted properly. |
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Sun Jun 9 10:08:24 2024, Carsten/Danyal, Detectors, Particle detectors - Recap of yesterdays work
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South (behind cooler) - "SA_SZ" - DD2...
We have put the particle detecotr North to the poistion behind the cooler (north) to replace the defective particle detector.
This detector is an old "Kozhuharov" style plastic szintillator that runs with a voltage of 1400-1500 V.
The signal line in the Messhütte / ESR is the #5 (normally we have #6).
North (behind target) - "NA_SZ" - ....
In the north we put one of my "spare" detectors that I assembled from "old" parts of not well known provenience (old plastic, old small 1 inch PMT). While machining the plastic szintillation material it seems that the mateerial got slightly to warm and shows micro cracks. Still the detecotr works without any issues and with good timing.
Please note that typical voltages here are ~600-700V.
The signal line in the Messhütte is the #5 (north outside) |
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