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Datataking Procedures

First Drs Calibration

Notice: dimscript for this procedure: ScriptsForDimCtrl/FirstDrsCalibration.dim

Remote-datataking: In case of remote data-taking this section can be skipped. In this case you can directly open the lid, and start with the data-taking including the DRS calibration.

0. Do _Start_ (DRS Calibration) in the fad-tab
1. Take *DRS: Pedestal* (1000 events)
2. Take *DRS: Gain* (1000 events)
3. Take *Pedestal* (1000 events)
4. Switch to FITS file format in the fad-tab
5. Take *Pedestal* (1000 events)
6. Switch on the temperature control (Feedback-tab: *Start*, *Enable output*)
7. Switch on the BIAS voltage (Set the global offset to one DAC count in the Bias tab and wait until the temperature feedback has ramped the voltages properly)
8. Take *Pedestal* (1000 events)
9. Switch off the bias voltage (*Set all to 0*)
10. Open the lid

Normal Datataking

0. Move the telescope to wobble position 1
1. Make sure Bias voltage is off
2. Do _START_ (DRS Calibration) in the fad-tab
3. Take *DRS: Pedestal* (1000 events, MCP *Start Run* on GUIs left side)
4. Take *DRS: Gain* (1000 events)
5. Take *DRS: Pedestal* (1000 events)
6. Switch to FITS file format in the fad-tab
7. Take *DRS: Pedestal* (1000 events)
8. Take *DRS: Time* (1000 events)
9. Do _RESET_ (DRS Calibration) to reset the secondary baseline in the fad-tab
10. Take *Pedestal* (1000 events)
11. Switch to FITS file format in the fad-tab
12. Send somebody out at the backdoor to measure the the sky-brightness with the sky-meter at the rough direction the telescope is pointing and write it down in the logbook
13. Take *Pedestal* (1000 events)
14. Switch Bias on (set to one DAC count and wait for the feedback)
15. Take *Pedestal* (1000 events)
16. Take *External light pulser* (1000 events)
17. Take data with full trigger area (four times 5 minutes)
18. Move the telescope to wobble position 2
19. Send somebody out at the backdoor to measure the the sky-brightness with the sky-meter at the rough direction the telescope is pointing and write it down in the logbook
20. Take *Pedestal* (1000 events)
21. Take *External light pulser* (1000 events)
22. Take data with full trigger area (four times 5 minutes)
23. Go on with the beginning of the data taking procedure

ratescan

0. Track a dark region
   • low zenith (<30°)
   • no bright star
   • no direct moonlight in the camera
   • examples
     • around 0:00 UTC: ra = 13.46667, dec = 27.12833
     • around 4:00 UTC: ra = 21.45, dec = 14.9
1. Take a run with type ratescan with unlimited event and unlimited duration (for configuring all programms)
2. Ratescan/START_THRESHOLD_SCAN x y c

variables:

• x: start threshold
• y: end threshold
• c: stepsize (if negativ ratescan starts with |c| and handle it dynamically, if the ratescan needs too much time)

Configuring manually:

• Stop ratecontrol (I'm not sure if this is necessary)
• ftmctrl/SET_DEAD_TIME 0 (in fact thats the minimum equal to 8ns (you can also set this value in the GUI)
• GUI: no interleaved pedestal, no interleaved extLP, only physic triggers

Ampl. vs Bias measurement

1. Track a dark region (same requirements as for the ratescan, see above)
2. Do a DRS calibration
3. Feedback/Start_Current_Control -1.0 (maybe Enable_Output yes)
4. wait for 2 - 3 feedback voltage corrections
5. switch to fits format
6. Now take an external lp run with 1000 events
   • be aware that for x = -1.0, -0.9, its possible to trigger 0 events. Than you can go on with the next overvoltage
7. Increase voltage offset by 0.1 V go on with the next light-pulser run
8. do this until +0.5 V offset

Write down following in the logbook:

• Offset
• median Voltage
• median Current
• runnumber

Dim Scripts

In FACT++/ScriptsForDimCtrl you will find the following scripts that could do parts of aboves procedures automatically.

script_name	function
FirstDrsCalib.dim	taking a first DRS calibration as described above
DataTaking1.dim	procedure from step 2 to step 18
DataTaking2.dim	procedure from step 21 to step 23 (which btw. is the same as step 16 to step 18)
ResumeDataTaking.dim	can be used if Datataking crashes during the first of a 4x5min run set to take 4 runs of 5 mins in a row
Take<source_name>.dim	procedure from step 1 to 23 with for Source <source_name> (2 Wobble positions)
AmplVsOv.dim	do steps 2 to 5 of the Amplitude vs Bias measurement with an overvoltage of x

Scripts can be started from a bash:

• dimctrl --batch ScriptsForDimCtrl/<scriptname>.dim

Scripts can be stopped via dimctrl --stop in a bash

if you want to only take the second wobble position the script can be started by: .x ScriptsForDimCtrl/Take<source_name>:2

scripts available for the following sources:

source	<script_name>
Crab	TakeCrab.dim
Mrk421	TakeMrk421.dim
Mrk501	TakeMrk501.dim
1ES1218+304	Take1218.dim