ELOG E0052

Reminder: Check signals in scope and in DAQ of detectors with voltages switched off (vs. CFD threshold)

When the ion pumps and vacuum gauges are switched off the scaler data of 
PMT_south, PMT_middle, PMT_north, PD_NO, PD_SO, PartDet North, PartDet South and (Channeltron) should be checked without voltages applied in dependence on the CFD thresholds to determine the "cable noise level" at which thre are NO entries other than 0 in hte spectra (minimum background).

Same for 2nd DAQ and Mesytec MSCF16

Mon Jun 3 18:24:44 2024

Rodolfo

PMT arrangement

The picture shows the actual configuration of the PMTs.

We are using a 4-Channel High-Voltage supply. The channels are labeled according to the PMTs names.

The suggested operation voltages are:

- PMT Nord (Type 9423, SN. 652): -2600 V
- PMT Mitte (Type 9423, SN. 653): -2500 V
- PMT Süd (Type 9422, SN. 1049): -1750 V

Tue Jun 4 22:54:02 2024

Rodolfo

PMT - Manufacture - Test Result Data

Wed Jun 5 19:22:43 2024

Carsten, Konstantin, Rodolfo

PMT tests and preliminary thresholds

For all channels of the CAEN CFD the width of the logic signal is set to 255ns (maximum) to mitigate potential double pulses. For the very low count rates of the experiment this is not problem.

Tested and (partially) set-up UV PMTs and Chenneltron with a UV LED.

The UV LED does not give a useful signal for the small-band VUV PMTs.
In general, (using the new cables?) it seems that the cable noise is very low and can be easily discriminated.
PMT south (the broadband) sees a regular "strong" pulse-train/burst of photon signals. Therefore, the PMT was exchanged against a different one (SolarBlind ET Enterprises Model 9422, SN1042) - same result. New data sheet is attached.
The channeltron has a rather broad pulse height distribution but very low background. CFD thresholds can easily be set. Very likely the best detector to adjust the laser timing?
Channeltron Head : -2.5 kV , CFD threshold 8 mV.
PD SO threshold needs to be checked (in Go4 the number of counts of PD SO is much lower than of PD NO). Present values: both 10 mV.
Voltage PMT north / middle (both small-band) : -2600V, PMT south (replacement): -1500V. All thresholds: 15 mV
CAEN CFD must be switched back to LOCK or it otherwise produces additional background

Both DAQs run with about 2 laser scan cycles, 201 steps. 90 shots each...
date written to files.

Thu Jun 6 19:42:20 2024

Exchange of amplifer channels / cables channels / HV voltage cables for PMT south

In order to check if the problem of regular burst of pulses on the PMT south is related to amplfier channels and or the HV cable, the cheannels of the amplifiers in the ESR were changed. Likewise, a different HV cable is now used for the supply of the PS.

The problem still persists. It is visible on all three cable lines from ESR to Messhuette (100x DAQ1 cables , and 10x / 100x cables DAQ2).

Fri Jun 7 15:29:50 2024

Rodolfo

Stored beam @ ESR

One of the first PMT signals from the stored-ion beam @ ESR

Sat Jun 8 12:02:20 2024

Test Particle Detectors - Det South not working

With the test beam from ESR I started to have a look at the PartDets.:
North outside: Works properly with a voltage of 1450 V
South outside (behind cooler) : no signal.

Later (when Danyal is here) we will check detectors cables etc., and if required put the north detector to position south and mount the untested (newly made, but with "old" material and PMT) spare detecotr to poistion north.

Sun Jun 9 10:08:24 2024

Carsten/Danyal

Particle detectors - Recap of yesterdays work

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)

Sun Jun 9 10:20:38 2024

Carsten/Danyal

Recap from yesterdays work with test beam (Detectors / beam /DAQ)

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):

PMT South ("braodband") ET9422	1500 V	thresh: 7
PMT Middle ("smallband") ET9423	2550 V	thresh: 9
PMT North ("smallband") ET9423	2600 V	thresh: 11

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.

Wed Jun 12 21:21:15 2024

Yuri

NTCap started

Fcenter - 244.6 MHz
BW - 10 MHz

Mon May 27 13:37:31 2024

Jan

MesyTec Shaper Control

For the 2nd DAQ the MesyTec Shaper (MSCF manual) is used as a spectroscopy amplifier and CFD.
It is controlled via the MesyControlGUI, which is installed on SADPC055 with a USB->mesyBUS connection to the MSCF.
The GUI can be started on any lxg-machine with the litv-exp account using the command/alias "E0052_shaper".

litv-exp@lxgXXXX:~$ E0052_shaper

The GUI will find connected devices automatically and should show this:

Double click on the connection icon of "5 MSCF-16" to open the full config pane

In order to save the settings to a local config file (bottom right), select "combined" writing mode on the top left. It is set to "hardware" by default.

Gain and ShapingTime can be set per group of 4 channles, PZ and CFD Thresholds can be set per channel.

Be aware that the "total gain" shown in the Gain panel is not correct by default. To calculate the proper gain factors, you need to go to the "Settings" tab of the device and set the follwong values:

Fri May 31 15:53:06 2024

Ruijiu Chen

run NTCAP system

NTCAP is working again. 
Connect the RF cable and the scaler cables to NTCAP system.
The map of signal is recorded in following link. 
https://elog.gsi.de/esr/E0018/2
Test it with IQ rate of 10 MSamples/s.
E0052/IQ_2024-05-31_15-04-34 
E0052/SC_2024-05-31_15-04-34

Fri May 31 16:49:52 2024

Wiring DAQ 1

Started to Check the wiring.

Status as of 2024-05-31

Inputs into 1. DAQ /TDC/Scaler - List according to file TLdaInputDescription.h in directory ~/go4/229Th

Cobra_Busy, // 0:
Next_Laserstep, // 1:
Laserscan_Complete, //2 :
{"PMT_South", 3, {3,11}},
{"PMT_Middle", 4, {4,11}},
{"PMT_North", 5, {5,11}},
{"Empty0", 6, {}},
{"ParDet_South", 7, {}},
{"ParDet_North", 8, {}},
{"QSwitch_500us", 9, {}}, // Important to mitigate missing Q-Switch
{"EmptyA", 10, {}},
{"Channeltron", 11, {9}}, //not yet wired
{"Bunch HF", 12, {}}, //not yet wired
{"PD_NorthEast", 13, {}},
{"PD_SouthEast", 14, {}},
QSwitch, //15
DC_Trafo, //16
{"Injection", 17, {}},
U_ECooler, // 18
I_ECooler, // 19
{"P_Gun", 20, {}},
{"P_Coll", 21, {}},
{"Common_Stop", 22, {}}, //? P_coll two times????
Clock_1MHz, // 23
{"Empty1", 24, {}},
{"Empty2", 25, {}},
{"Empty3", 26, {}},
{"Empty4", 27, {}},
{"Empty5", 28, {}},
{"Empty6", 29, {}},
{"Empty7", 30, {}},
{"Empty8", 31, {}},

Checked also the connections from the CFD to DAQ 1 (ok)
input connections to CFD are as labelled on the black laser Messhütte panel

CFD channels:

0: PMT south
1: PMT niddle
2: PMT north
3: PMT copper (not used)
4: PD NO
5: PD SO
6: Part Det South
7: Part Det North
8: empty
9: XUV front (not used)
10: XUV back (not used)
11:
12: Master Osci Bunchng HF (Süd)
13: empty
14: empty
15: Master Osci Bunchng HF (Nord)

PD_NO and PD_SO are terminated with 50 Ohm at input (conflicts with 50 Ohm input termination of CFD)

Sat Jun 1 18:00:20 2024

ReadOut Trigger im Timer Scaler changed because of faulty signal from frequency generator

Old readout trigger (~200 Hz) in 1MHz Scaler showed two nearby peaks indicating a jitter of the readout frequency or same faulty output driver of the frequency generator Metrix GX240 used to produce the readout frequency (see below).

Used the 1 kHz clok instead divided by 5 -> only a single peak in 1MHz spectrum in the scaler (see below).

This should be used during the beamtime.

Sat Jun 1 19:00:57 2024

Change of (offline) frequency for common stop (CS) of VUPROMs (and 2nd TDC) and scaling factor

Temporarily, for tests of the second DAQ I changed the frequency from the frequency generator and scaling factor that is used for the common stop signal to a value that is close to the expected value in the experiment.
Reason: For the second TDC (CAEN 25ps) TDC the time between to CS events must be of the order of 45 us. The TDC can store events up to about 51,x us and allows for overlap of these regions to be able to stitch together the events to a continuous time axis.

Since we plan to run at ~ beta= 0.5566 the revolution frequency is about

f=1.540974 MHz (0.6489 us)
This value is used in the frequency generator.

The scaling factor is set to 68.
=> 68 x 0,6489us = 44,1252 us between to CS.

Of course later the real RF value from the accelerator will be used.

Please leave or, if required to change, mark in ELog.

Sun Jun 2 00:01:46 2024

25ps TDC CAEN V1290N DAQ2 lead to crash in DAQ2 due to a hardware issue

On the CAEN V1290N TDC the piggy board for the lower 8 channels is not fixed well to the motherboard.
That prevented to the whole DAQ2 to trigger correctly or even crash every once in a while. Long attempt sot find the error in hard and in software.

I fixed/reattached the piggy board, but be careful with the attached Lemo cables. They might loose the board again (it used to fixed with hot glue).

DAQ2 now also seem to run smoothly.

Thu Jun 6 09:23:53 2024

Konstantin Mohr

Timing

The best way to adjust the bunch-laser timing is to start go4 (mbs must be running) from atppc023. Therefore use x2goclient and use the predefined session to access LXG1297. Start go4 as usual (Entry 10 + Entry 11).

With this preparation one can directly observe changes in the relative time between the common stop trigger and the photodiode signals (see Screenshot 3) when rotating the upper channel's fine adjustment wheel of the right dual timer above the laser table (see Screenshot 2, Don't touch the coarse adjustment wheel directly above!!!).

To ensure proper operation of Go4 make sure that it is closed in the ssh-session after the correct timing has been set!!!

Thu Jun 6 09:39:23 2024