Starting a run in the RAL 1.8T test rig

The procedure for testing a batch of VPTs in the RAL 1.8T test rig is described here.

1.  Unloading the rig

Before starting a new run, VPTs from the previous run must be removed.

1. Ensure that the magnet power and the HT to the rig are OFF.
2. Remove the clamp which secures the rig during the run.
3. Unplug the interlock arm.
4. Slide the rig out of the magnet.
5. On the PC next to the rig, clear the list of VPTs:
   • Scan "Clear All" barcode
   • Scan "monitor" to C8
   • Scan 88213 to f8
   • Type 94025 into D1 (no scan label available yet)
6. Remove the VPTs from the rig and store in a tray.
   • DO NOT remove the VPTs in E5, F8 or D1

2.  Loading new VPTs into the rig

1. Load new VPTs:
   • Scan can label (on cans for D & E, on PC table for row F)
   • Scan VPT barcode
   • Scan ENTER
   • Clean VPT faceplate
   • Insert VPT into can (yellow -> Kathode, blue->Dynode, white->Anode)
   • VPT 37 should not be removed, but moved along to the next can (D2,...D8,E1,...)
2. Scan "SAVE-POSNS" and "ENTER" to store the VPT position file.

3.  Carry out preliminary current check

A small proportion of VPTs draw sufficient dark current to prevent the run from continuing.  In order to weed these out quickly, carry out the following check.  This will also detect channels which are likely to saturate.

1. Switch the rig to OVERRIDE, using the key which is hung on the electronics rack in the control room.
2. Start the LabVIEW program which should be running on the control room PC.
3. Click the purple "Utility" button.
4. Check anode and dynode currents for B=0, angle=0.
5. Click button "Occupied".
6. Click button "Start" to start the global current check.
7. Click C8, then step through all of the channels.  Look out for channels reading above 1600, especially in row E, as these are likely to saturate during the run.  Moving the high-yielding VPT to another channel may well solve the problem.

4.  Start the test run

1. Switch the rig back to NORMAL, remove the override key, and hang it back on the rack.
2. Start the LabVIEW program.  The rig will the run through the standard series of measurements.  This process usually takes about 4 hours.  The measurement sequence is:
   • Dark current  (all channels)
   • Dark current channel by channel
   • Switch magnet on to warm up
   • Measure response of VPTs v angle in magnetic field
   • Measure response of VPTs v magnetic field at a fixed angle

5.  Keep the run log files up to date

The barcodes and locations of the VPTs in the current run are stored in the file VPT_Names_and_Locs.txt in the VPTConfig directory.  The following files should be edited when the run has started.

1. Logbook-2006.xls - enter run details
2. RIE-VPTs-tested.xls - summary of VPTs tested by data
3. RIE-VPTs-location.xls - track which VPTs are in each tray

Bruce Kennedy 01/08/06