--obsolete-- Flammable Gas Warning @ DRAGON Ion Chamber

by Aurelia Laxdal, as per Dave Hutrcheon, Nov. 17, 2005

A flammable gas monitor has been placed under the Ion Chamber detector at the tail end of DRAGON. It is connected to a control panel/ annunciator located on the East wall of the ISAC experimental hall.

If the DRAGON isobutane alarm goes off:

1. ISAC or cyclotron operators should attempt to contact a DRAGON experimenter at 7514 (couting room) or on the experimental hall floor around DRAGON. If none can be contacted, follow the instructions (below) for DRAGON experimenters.
2. DRAGON experimenters: Go to the control unit by the LN2 fill station at the East wall. Note the status indicator lights and %LEL reading for Detector 3. The reading must be over 20% LEL for an alarm to be generated. The alarm is non-latching, and will only clear after the reading falls below 20%. Note the time and above status info in the DRAGON logbook and as a "Faults" item on the whiteboard in the H.E. counting room. Inform Operations that this has been done. If alarm persists:
   1. Turn down the IC/PGAC high voltages, slowly to protect the pre-amps. The HV's are two channels of the Bertran units in rack 27B. The labels "IC anode" and "IC cathode" indicate the two channels of HV for the Ion Chamber.
   2. Shut off the isobutane Supply valve (#20) mounted to the right of rack 27B overhead on the cable tray. Isobutane in the IC/PGAC should slowly pump away. This hsould appear as a gradual reduction in reading of the differential pressure gauge DRA:DPG61 in the DRAGON EPICS page accessed by "Vacuum|ED2 to IC".
   3. Inform ISAC Operations. Stop delivery of beam to DRAGON.
   4. Call an IC/PGAC expert. Note the incident in the DRAGON logbook and on the Faults list on the H.E. counting room whiteboard. People to call are:
      • Christof Vockenhuber 778-230-1711
      • Dave Hutcheon 604-224-7058
      • Jac Caggiano 604-696-6178 [no longer at TRIUMF]
      • Chris Ruiz 604-734-3140

D. Hutcheon

16 Nov 2005