Diagnosing bad quadrant problems

ADSC Quantum-4 and Quantum-210 detectors each have four CCD chips, each with its own readout electronics. Signals from the electronics feed into 1-4 PC's, depending on the detector. Occasionally, images from a detector will have one bad quadrant (either blank or with a striped appearance). The first thing to try in this case is taking a new dark-current image. If this doesn't help, the next step is to determine whether the problem lies with the readout electronics, the PC, the CCD chip itself, or communications between components. For this, it is helpful to swap components around and observe whether the bad quadrant's position changes or not.

Swap computers for the Q-210; if a different quadrant is bad after the swap, suspect the LionM interface board in the computer, or possibly the computer's CPU or memory. The procedure is:

1. Stop ADX software on the data collection computer.
2. Have OPERATE Detector running on the PC's and start Quantum Console on one of them. Use it to warm up the detector to room temperature, then exit from the program. If you are in a hurry, this step may be omitted.
3. Stop all OPERATE Detector processes.
4. Power off the PixelVision controller.
5. On the first PC, edit the file D:\pv_sw\bin_441\detector_db.txt (for detector 448, the directory is D:\pv_sw\bin_448), to swap the computers controlling the bad quadrant and a good one. For example, change:

   chip 2160 2124 2048
   host 448-0 1
   host 448-1 1
   host 448-2 1
   host 448-3 1
   module ? slave   4269 0  180  448-0 9041 9042 9049
   module ? slave   3932 1  270  448-1 9041 9042 9049
   module ? master  4278 2   90  448-2 9041 9042 9049
   module ? slave   4264 3    0  448-3 9041 9042 9049
   

   to

   chip 2160 2124 2048
   host 448-1 1
   host 448-0 1
   host 448-2 1
   host 448-3 1
   module ? slave   4269 0  180  448-1 9041 9042 9049
   module ? slave   3932 1  270  448-0 9041 9042 9049
   module ? master  4278 2   90  448-2 9041 9042 9049
   module ? slave   4264 3    0  448-3 9041 9042 9049
   

6. Shut down the PC's involved in the swap (they need not be powered off).
7. Swap the fiber optic cables coming from the detector between computers.
8. Restart the PC's, and log in.
9. Power on the controller.
10. Start the OPERATE Detector processes on all the PC's. There may be difficulty communicating with the detector; if so, stop all OPERATE Detector, cycle power on the controller, and try again.
11. On the data collection computer, edit $CCD_HOME/tables/detector_db.txt to match detector_db.txt on the PC's.
12. Start up the ADX software ("start_ccd") on the data collection computer and take an image.
13. If the detector will be used for data collection, or a series of test images, at this point, cool it down (stop ADX software on the data collection computer, use Quantum Console on the first PC) and proceed to collect images in the normal way.