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  13   Thu Mar 3 17:34:42 2022 RodolfoLaserPump Laser
We have issues with our Pump Laser (Spectra Physics - Quanta Ray Pro). After the service made on mid Dezember (2021) the laser does not get started. After contacting the service many times, the technicians think it can be an issue with the flashlamps.

- Flashlamps installed technician on 15.12.2021: FAILED.
- Flashlamps installed by Rodolfo on 21.01.2022: FAILED.
- Flashlamps installed by Rodolfo on 08.02.2022: WORK, however

the power is dropping extremelly fast. The measured power on 08.02.2022 was 21.6 W. On 01.03.2022 we measured 17,8 W (for 2.7 Millon shots). The flashlamps should stand 30 Millon shots without losing too much power.
Attachment 1: QRAY_Simmern.jpg
QRAY_Simmern.jpg
  38   Tue Mar 29 21:37:13 2022 RodolfoLaserPump Laser
The gold "reflectors and end plates" of our pump laser (Quanta-Ray PRO) have been exchanged by new ones.

- Output power after Oscillator and Amplifier (@ 1064 nm): 41 W.
- Output power after Second harmonic crystal (@ 532 nm): 18.2 W.
- Aditionally, we (Simon and I) have replaced the axial blowers in the power supply.

The picture shows the "old" gold reflectors.
Attachment 1: QRay_GoldReflektoren_2010-2022.jpg
QRay_GoldReflektoren_2010-2022.jpg
  135   Thu Apr 7 10:10:31 2022 Ragan, Yuri, DanyalAcceleratorProblem in UNILAC
The power supply of the UNILAC magnet is broken. The repair will take up to 6-7 hours.
  22   Fri Mar 18 16:58:26 2022 RodolfoAcceleratorPressure at North-East Arc
The pressure at the north-east arc of ESR, where the laser window is located, looks suspicious. The sensor E01LF02 shows a value of 7.26E-8 mbar. For comparison I have also upload a photo taken on 07.02.2022 where the pressure was 4.62E-10. We have contacted the vacuum expert and asked for his opinion. Waiting for the reply ...

Bilder: R. Sánchez
Attachment 1: Druck_E01LF02_18-03-2022.jpg
Druck_E01LF02_18-03-2022.jpg
Attachment 2: Druck_E01LF02_07-02-2022.jpg
Druck_E01LF02_07-02-2022.jpg
  23   Mon Mar 21 09:18:28 2022 RodolfoAcceleratorPressure at North-East Arc
Our vacuum expert has reply. The "IZ Pump" in this region was off.


Quote:
The pressure at the north-east arc of ESR, where the laser window is located, looks suspicious. The sensor E01LF02 shows a value of 7.26E-8 mbar. For comparison I have also upload a photo taken on 07.02.2022 where the pressure was 4.62E-10. We have contacted the vacuum expert and asked for his opinion. Waiting for the reply ...

Bilder: R. Sánchez
  Draft   Wed Sep 8 21:44:55 2021 RodolfoGeneralPreparation
StatusArbeitspaketKommentare
Laser und Laserlabor
***FarbstofflaserElektronik wurde erneut.
  57   Fri Apr 1 18:30:38 2022 CarstenDetectorsPositions / Voltages threshlds for particle detectors
DC beam 238U92+ (205kV, e-beam)
We used the detector NA_SZ to determine the central primary-beam (238U92+) position by observing the Schottky-signal while moving the detector inside.

The beam position is 43 mm (wehre the beam is almost gone").

NA_SZ
In the pocket of the NA_SZ we mounted the thick "old pilot U" scintilator since the original one foreseen is defect, see other post.
CFD Model CAEN N853
800V position 20mm pulse height 1V
750V position 10mm pulse height 0.82V, CFD, Ch7, 247, (247mV according to manual)

SA_SZ
Check positions and voltages of the detector behind the cooler
Yesterday the setting of the scope was x10, so the values written in that post were wrong.
At present we position -20, 1400V, pulseheight 1C, CFD, Ch6, 250 (250mV according to manual)

Scraping from the inside with NI_SZ touches the primary ion beam at 28 and destroys the beam at 27 mm. Thus, the beam presently is on a very inner orbit.
  43   Thu Mar 31 17:56:32 2022 KonstantinDAQPhotodiode test signal
We used a signal generator to provide a 4MHz dummy-RF signal. This was divided by a factor of 2 for laser-"bunch" synchronization and by a factor of 200 for to provide the stop-tigger attached to the DAQ. With this Dummy-RF we were able to measure the relative arrival times of the laser at the photodiodes located in the laser towers. Note that the signal of the southern photodiode arrives first. This is because the scale of the time axis is given in (10/3ns)-bins since the last common-stop.
Attachment 1: Timing_Photodiodes.png
Timing_Photodiodes.png
  35   Fri Mar 25 14:31:24 2022 RodolfoLaserPhotodiode signal SO in the Messhütte
Measured at the Panel "Messhütte - Laserhütte", BNC "Fast PD / SO".

- Average over 256 samples
Attachment 1: PD_SO_Signal_MH_25-03-2022.PNG
PD_SO_Signal_MH_25-03-2022.PNG
  33   Thu Mar 24 16:59:35 2022 RodolfoLaserPhotodiode signal SO
Fast Photodiode signal at the "SO-Bogen" (South-east arc).

- Average made over 250 samples.
- The photodiode is placed after two HR (high reflexion) mirrors.
Attachment 1: FastPD_SO_Signal_24-03-2022.jpg
FastPD_SO_Signal_24-03-2022.jpg
Attachment 2: FastPD_SO_24-03-2022.jpg
FastPD_SO_24-03-2022.jpg
  68   Sat Apr 2 18:17:31 2022 YuriAcceleratorPhoto-Identification
Just a photo of the ID
Attachment 1: 9FFA52AA-1F75-470E-AD1B-E1A612A3F7D6.jpeg
9FFA52AA-1F75-470E-AD1B-E1A612A3F7D6.jpeg
  37   Tue Mar 29 12:47:26 2022 Ken Ueberholz Parameter setting for XUV and copper mirror detector 
Some Default Settings for the XUV 
Detector. The copper 
mirror should always move fully in.

Possible positions: Between 0mm and 147mm. 
Background was 
very high for anything higher than 100mm 
in the last 
experiment. 50mm was optimal. This should 
be tested again 
with repaired and modified shields. 

Good default values for the XUV detector 
parameters have 
been proven before to be:

Cathode: -5V
Movable shield: 0V
Fixed shield: 0V
Main coil: 8A
Secondary coil: -2.4A

(negative values set in hardware, only 
positive software 
inputs are possible)
  60   Fri Apr 1 23:47:45 2022 CarstenDetectorsPMT thresholds / PMT north does not allow voltage abow ~ -1kV
Checked thresholds of PMT with beam and without beam.

The PMT "south" which is now at the gas-jet target has burst-like pulses with a train of many short pulses of duration of about 1us. The signals are taken out of the ADC of the 2nd DAQ (but are still in the VUPROM TDC).

The PMT "middle" (broad-band VUV) has a quite high count rate of about 4-kHz at a few 10e7;; ions in the ring. The rate is very low without ions in the ring but it does not fully scale to low intensities.
At low intensities of a few 10e5;; we still have more than 100 Hz.
For a PMT voltage of -1800V a threshold of 20mV was set which is ok an d we leave it


Note: We see a noise beat of 6ns and 55ns with amplitude of about 15mV to 20mV. The high frequency disappears if we use a battery scope.

PMT "north" small-band VUV
We tried to put the voltage to the wanted level of -2500V. It was not possible to set a voltage higher than about -1000V. WIth this voltage the PMT draw a current of about 200uA and at a voltage above this value it dropped to zero and switched off.
We need to have a closer look at the PMT in the ESR tomorrow with some specialist knowledge.
  95   Tue Apr 5 11:14:52 2022 Sebastian, Kristian, Pierre-MichelDAQPMT over wavelength histogram v2
Today we finalized the PMT over wavelength histogram in:

Analysis/Histograms/Step2_Anl/LabView/laserscan

Currently the histogram shows the PMT middle signal on the y axis.

Remark: Tomorrow we create this kind of histogram for all PMTs.
  87   Mon Apr 4 15:27:31 2022 SebastianDAQPMT over wavelength histogram
Kristian and I tried to create a "PMT over wavelength" histogram under step2Anl/LabView.
Unfortunately, the code ist still in progress and does not work yet.

The current code can be found in the TldaAnlProc.cxx
  28   Wed Mar 23 11:20:55 2022 SimonDetectorsPMT operating voltages
During the testing of the PMTs the following operating voltages were applied:

PMT Cu: -1300V
PMT Nord: -2500V
PMT Mitte: -1800V
PMT Süd: -1800V

Further optimization will be necessary during background measurements.
  58   Fri Apr 1 22:01:14 2022 KonstantinDetectorsPMT operating voltages
> During the testing of the PMTs the following operating voltages were applied:
>
> PMT Cu: -1300V
> PMT Nord: -2500V
> PMT Mitte: -1800V
> PMT Süd: -1800V
>
> Further optimization will be necessary during background measurements.

Currently, PMT Süd shows a strange behavior resulting in after-pulses up to 1µs. Therefore, the high-voltage was reduced to -1500 V.
However, the after-pulses remain. This should be investigated in more detail at some other point.
  219   Tue Apr 12 14:52:19 2022 RodolfoDetectorsPMT Nord, Middle. Datasheets
Attached are the datasheets for the solar-blind PMTs.

- PMT Nord. Type 9423. SN: 650
- PMT Middle. Type 9422. SN: 1049
Attachment 1: ET-Enterprises_DataSheets_PMT_9423-9422.pdf
ET-Enterprises_DataSheets_PMT_9423-9422.pdf ET-Enterprises_DataSheets_PMT_9423-9422.pdf ET-Enterprises_DataSheets_PMT_9423-9422.pdf ET-Enterprises_DataSheets_PMT_9423-9422.pdf ET-Enterprises_DataSheets_PMT_9423-9422.pdf
  97   Tue Apr 5 13:24:40 2022 KristianDetectorsPMT Cu
HV cable was in wrong channel in power supply. Now it is back to the correct position. Checked connection at the PMT.
  188   Sat Apr 9 19:09:57 2022 RodolfoLaserOptimization - Resonator of dye laser
I have tuned a bit the resonator of the dye laser.

The total output energy after the main amplifier is 86 mJ (@ 645,6 nm)

The laser wavelength read by the wavemeter appears to be more stable (on the windows computer). We can see the histogram once the present scanning is finished.
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