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Change the Threshold of the BGO Array

The BGO array threshold is altered by changing the thresholds of CAMAC constant-fraction-discriminators (CFSs). Two calibration runs were taken, giving calibration points used to adjust the CFD threshold. These points have been used to configure the CFD for different thresholds.

  1. To change the BGO thresholds, go to the MIDAS status page https://smaug.triumf.ca:8443/ and click on "Adjust BGO Thresholds on the left menu bar."

  2. Adjust the threshold (see Fig. 1) (in keV) and hit enter.

    3. Fig.1 - Adjust BGO Threshold.

  3. Now, to apply the threshold you just set, go back to the status page and select "Apply BGO Thresholds" on the left menu bar.

  4. That's it.

Alternatively, you can change the thresholds, or any other odb value via odbedit:

  1. Open a terminal and login to dragon@smaug.triumf.ca.

  2. cd online/odb

  3. Type: odbedit

  4. cd Script/Apply BGO Thresholds

  5. Type: set "Threshold Gamma Energy" 1000.

    And you will see:

    Executing script "/Users/dragon/online/thresh/thresh 1000"

    13:47:02 [thresh,INFO] Program thresh on host smaug started

    13:47:02 [thresh,INFO] Set all CFD thresholds corresponding to a gamma energy of 1000 keV.

    13:47:02 [thresh,INFO] Program thresh on host smaug stopped

    You may still have to apply thresholds afterwards

Dario Gigliott
17 September, 2001
JEP
22 December, 2005
Annika Lennarz
Updated 22 January, 2019