 Thu Mar 24 16:59:35 2022, Rodolfo, Laser, Photodiode 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. |
|
Fri Mar 25 14:31:24 2022, Rodolfo, Laser, Photodiode signal SO in the Messhütte
|
Measured at the Panel "Messhütte - Laserhütte", BNC "Fast PD / SO".
- Average over 256 samples |
|
Tue Mar 29 12:01:08 2022, Rodolfo, Laser, Laser targets
|
I have installed two targets* (size: 2 inches) to monitor the position of the laser beam.
- The internet cameras can be accessed from any browser, but only inside the GSI-Campus network. Benutzername: admin. Kennwort: 1234
- Target SO (UV-Laser IN). Internet camera: atpdev005.gsi.de **
- Target NO (UV-Laser OUT). Internet camera: apdev17.gsi.de
- To move a specific target "in" or "out" the way just choose the target in the "target control box" and press the green bottom.
* The material of the target is Frosted Glass (Thorlabs: DG20-15ß00-H2-MD).
** The camera hang sometimes. |
|
Tue Mar 29 21:37:13 2022, Rodolfo, Laser, Pump 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. |
|
Wed Mar 30 09:27:15 2022, Rodolfo, Accelerator, Issue? Scrapers at E-Cooler
|
Carsten* forwarded me an E-Mail from Markus yesterday. "Betreff: Scraper im ESR Elektronenkühler"
- Markus has tried to get moving the scrapers at E-Cooler last week. But he got some issues.
- The expert (Herr Robert Boywitt, Abteilung BEA) has been contacted and he is working on this issue.
- The scrapers move in one follows the instructions (please attached screenshot).
- However it was also noticed that the actuators for the scrapers show now tolerance of "2 mm".  This can affect the accuracy and the reproducibility of the ion- and laser-beam positions, e.g the overlap.
* he was so lazy that he could not post this in the ELog. |
|
Fri Apr 1 15:27:00 2022, Rodolfo, Detectors, Nitrogen for UV-PMTs
|
There was a question concerning the nitrogen we use to rinse the "Solar Blind PMTs".
- I have checked the nitrogen flow rate this afternoon (14:00) and it was a level of 0.2 LPM.
- I have increased this now to 0.4 LPM.
In the pictures below you can see where the "fine tunning" valves are located.
Bilder: R. Sánchez |
|
Fri Apr 1 15:52:23 2022, Rodolfo, Detectors, UV PMT South
|
The "Solar Blind PMT" labeled as "PMT South" has been installed by Simon and Max in the gas target chamber on a CaF Viewport. The PMT is pointing directly to the center chamber.
- I have covered the support of the PMT and the flange with additional aluminum foil in order to try to reduce the straight light.
- I will check the signal of the PMT as soon as the lighting inside the cave will be turned off.
Bild: R. Sánchez |
|
Sun Apr 3 11:01:57 2022, Rodolfo, Accelerator, Scrapers @ E-Cooler
|
We the mid- and night shift (Wilfried, Simon, Patrick, Ken and me) we not able to manipulate the scrapers in the E-Cooler.
- Carsten contacted Markus concerning this issue.
- Markus replied one should follows the instructions he forward us. They are given in Entry 39 (this e-log)
- Zitat vom Markus:
"ich hatte die Scraper ja letzte Woche getestet und war zu einem vergleichbaren (Negativ-)Resultat gekommen.
Daraufhin hatte ich den Experten gebeten, die Scraper zu überprüfen, was in der Anleitung resultierte, die ich Carsten geschickt habe.
Im Gespräch habe ich verstanden, dass das Problem in der (modifizierten ?) Frontend-Software liegt.
Da nützt dann auch ein anderes Programm, ähnlich Nodal, nichts. Nodal gibt es nicht mehr, das Programm Prophelper bietet jetzt vergleichbare Möglichkeiten, aber da muss man schon wissen, was man tun will/tut."
Google translation:
"I had tested the scraper last week and had come to a comparable (negative) result.
I then asked the expert to review the scrapers, which resulted in the instructions I sent to Carsten.
During the conversation I understood that the problem lies in the (modified ?) frontend software.
Then another program, similar to Nodal, is useless. Nodal no longer exists, the Prophelper program now offers comparable options, but you have to know what you want to do/do." |
|
Tue Apr 5 20:16:13 2022, Rodolfo, Laser, Discriminator for HF reference signal
|
For the laser trigger we need to generate a few ns NIM-puls from the HF reference signal. Therefore we (Wilfried, Konstantin and me) have changed the constant fraction descriminator (CFD) to generate this kind of pulse.
- We are using now the module N843 from CAEN, see picture below. With this we could now produce ~20 ns long pulse.
- This signal is also used as STOP trigger for the VUPROMs |
|
Wed Apr 6 14:52:29 2022, Rodolfo, Runs, Scraping the ion beam
|
| We are T-scraping the ion beam. |
|
Sat Apr 9 16:55:19 2022, Rodolfo, Laser,
|
16:15 I have changed the dye (of both oscillator and amplifier).
16:27 I have increased the pump energy (@ 532 nm) from 476 mJ to 507 mJ.
- UV output energy @ 322,8 nm: 12 mJ. (Before was at 9 mJ).
- New calibration factor is 160 for Quanta Ray monitor signal. |
|
Sat Apr 9 19:09:57 2022, Rodolfo, Laser, Optimization - 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. |
|
Sun Apr 10 15:29:53 2022, Rodolfo, Laser, Status - Laser system
|
We have checked the laser system.
- The pump laser has ~ 23Mio shots. The total output energy has dropped to about 475 mJ. Maybe it is time to install new fresh flashlamps. In case the accelerator is going to have any mantainance tomorrow (Monday) then we can take the oportunity to exchange the flashlaps.
- The dye laser is pumped with 470 mJ (angle of lambda/2 plate = 112°).
- The energy after the second harmonic is 11,3 mJ @ 646 nm. We are using the Sarper's calibration table (635 nm - 646 nm) |
|
Mon Apr 11 18:57:18 2022, Rodolfo, Laser, New flashlamps
|
We (Sarper, Konstantin and me) have changed the old flashlamps (with ~ 26 Mio. shots) by new "fresh" ones. We have also exchange the dye. Here are some parameters of the laser we measured with the new flashlamps and dye*:
- Output energy after the Quanta-Ray (@ 532 nm): 598 mJ.
- Seed energy for Cobra (@ 532 nm): 505 mJ.
- Correction factor for monitor; 15.9.
- Output energy after Cobra's main amplifier cell (@ 640 nm): 107 mJ.
- Output energy after SHG (@ 320 nm): 15.8 mJ.
* all values are average over 500 shots.
** below you can see a picture of the "old" flashlamps. |
|
Tue Apr 12 14:52:19 2022, Rodolfo, Detectors, PMT Nord, Middle. Datasheets
|
Attached are the datasheets for the solar-blind PMTs.
- PMT Nord. Type 9423. SN: 650
- PMT Middle. Type 9422. SN: 1049 |
|
Tue Apr 12 15:05:56 2022, Rodolfo, Laser, Laser status
|
We have checked the laser power at 14:15 *
- Pump energy after Q-Ray @ 532nm: 559 mJ.
- Seed energy for Cobra @ 532 nm: 505 mJ (before 481 mJ).
- Correction factor for monitor: 28.8.
- UV-Energy after SHG @ 321.6 nm: 13.7 mJ.
* All values are averaged over 500 shots |
|
Wed Apr 20 10:09:50 2022, Rodolfo, Laser, Optic with spots
|
| The average energy produced by the laser along the beamtime was about 10 mJ/puls. After about two weeks of beamtime some of the optics, especially the optic placed just after the BBO crystall, got some spots, see pictures below. Here the diameter of the laser beam is about 6 mm. |
|
Mon Apr 4 09:10:44 2022, Ragan, Yuri, Rui-Jiu, Runs, Measurement
|
NTCAP is taking data with the beam with a stop at manipulation 5 (taking all the fragments).
1)
Start time: 09:07
Stop time: 11:31
Reference level: -25 dBm
SC_2022-04-04_09-07-57
IQ_2022-04-04_09-07-57
2)
Start time: 11:35
Stop time: 14:00
Reference level: -25 dBm
SC_2022-04-04_11-35-25
IQ_2022-04-04_11-35-25 |
|
Fri Apr 8 10:44:55 2022, Ragan, Yuri, Danyal, Sergey, Runs, NTCAP stopped
|
NTCAP is stopped. Sergey will now set an ion bunch instead of two in the ESR.
SC_2022-04-08_09-39-33
\IQ_2022-04-08_09-39-33 |
|
Thu Apr 7 09:58:55 2022, Ragan, Yuri, Danyal, Accelerator, Kicker problem solved
|
The kicker problem is solved and the beam is back in the ESR. |