We tested the PMTs again, this time with an UV LED that is mounted at a window close to the XUV detector.
PMT south showed a very clear increase in count rate from about 1 to 50 Hz.
PMT mid also showed a small increase by a few Hz.
For PMT north there was no great change between LED off and on, but we think that the count rate also very slightly increased. Note, that PMT north is also the furthest away from the LED.

Also we saw a difference between single- and multi-photon events at PMT south.

• ECEDS1VU: Verriegelt mit ECEDS1HA. Der Antrieb kann nur fahren
  wenn der Antrieb ECEDS1HA in Position -4,0 steht.
  
  
• ECEDS1HA: Verriegelt mit ECEDS1VU. Der Antrieb kann nur fahren
  wenn der Antrieb ECEDS1VU in Stellung EI steht.
  
  
• ECEDS2VU: Verriegelt mit ECEDS2HA. Der Antrieb kann nur fahren
  wenn der Antrieb ECEDS2HA in Position 0,0 steht.
  
  
• ECEDS2HA: Verriegelt mit ECEDS2VU. Der Antrieb kann nur fahren
  wenn der Antrieb ECEDS2VU in Stellung EI steht.
  

I have prepared new (fresh) dye solutions of Fluorescein 27: 2 charges. They are in the Safety Cabinet (Sicherheitsschrank) in the ESR Laser lab

Cobra's FCU was recalibrated. Table saved as FCU_547-554_RS_2024-06-25.fcu.

We have made two foam rings (outer diameter ca. 70 mm with a thickness of 10 mm each and placed them successively underneath PMT north. 

ring 1: ID = 55 mm 
ring 2: ID = 47 mm 

Without rings we had measured ca. 20 counts per channel in a time of about 7 minutes. (1st picture below) 

With ring 1 we have measured ca. 18 counts per channel in 7 mins. 

with ring 1 and ring 2 we have measured ca. 15 counts per channel in 7 mins. (2nd picture below)

It is clear that the rate of PMT north decreases with increasing distance from the beampipe. 

At this point it is not yet clear to us if the experiment will benefit from the 2 rings. 

If the rings should be implemented, we propose to have one proper ring (20 mm high) made by the mechanical workshop. 

We have switched off all 3 PMTs  !

1. Open additional views, options are "Display" (figure of recent values), "MBS Messenger" (connection status with MBS, lower part of Attachment 2), "Devices View" (most recent values of different devices, right part of Attachment 2)
   
2. Make sure that "Make Data Available to MBS" is selected
   
3. Definition of laser scan Parameters. The laser will perform an automated scan between the selected wavelengths. It's possible to define an increment or a number of laser steps as scan parameter. After the laser has received the specified number of rising edges on Trigger port #1 (Do not change the port number, since this corresponds to the Hardware setting!) the laser advances to the next frequency until the number of steps and scan repetitions is completed. There is an option to start the laser scan automatically, when a trigger was received on port #3 (The cabling is done. However, the pulse generation must be provided from SCU sddsc221 channel IO1 of timing receiver tr1 whenever needed).
   
4. The button can be used to start and stop a scan. In some cases there might occur an USB communication error with the laser, which can also be reset by this button.
   
5. IMPORTANT NOTE: Make sure that the FCU is enabled, since otherwise the BBO of the FCU does not follow the wavelength of the laser, which results in NO UV output power.
   
6. After "Make Data Available to MBS" option (see 2.) has been selected, Medusa is awaiting the MBS client to connect.
   
7. View of most recent parameter settings.
   

1. Start medusa as described above
   
2. Connect to "r4l-41":
   atplaser@lxg1297:~$ ssh atplaser@r4l-41
   
3. Change to the directory of the Th-MBS version:
   R4L-41 > cd mbsrun/E0052/DAQ1
   
4. Make a reset (optional):
   R4L-41 > resl
   
5. Start mbs:
   R4L-41 > mbs
   
6. Once you are in the mbs environment start the acquisition:
   mbs > @startup
   
7. Connect to the file server:
   mbs > @connectdisk
   
8. Start acquisition:
   mbs > sta ac
   With this command, the connection to the Medusa server should be established. This can be verified by the line
   -R4L-41 :read_meb :connected succesfully to LabView Server.
   of the MBS output, and in the MBS Messenger View of Medusa stating
   Connected! Established connection to ...
   
   
9. Open file:
   mbs > @openfile
   
10. Press Run-button in the Go4 analysis (must be started beforehand)
    
11. Start laser scan in medusa
    
12. Press Stop-button in the Go4 analysis
    
13. Close file:
    mbs > @closefile