NLCTA Safety ProceduresBeam Containment Checks

Beam Containment Checks

Purpose

These Beam Containment Checks are used to verify the integrity of beam containment devices, including the beam power limiting circuits.

Applicability

The NLCTA Engineering Operator in Charge (EOIC) completes the Beam Containment Checklist, as required by the BAS. The completion of these checks is recorded in the Header of the NLCTA Operations Logbook and on the Weekly Beam Containment Checklist.

Approval


NLCTA Operations Manager / Date

NLCTA Safety Officer / Date

Accelerator Department Safety Officer / Date

Instructions for Completing Daily Beam Containment Checks

  1. Establish beam conditions and observe beam current signal on gun girder faraday cup 340, toroid 355, or any profile monitor.
  2. Repetition Rate Limit Test
  3. Press the Rep Rate Test button on the NLCTA Tuning panel. This increases the repetition rate for the gun to 12 pulses per second.
  4. Observe the absence of beam current.
  5. Press the Restore Rep Rate button on the NLCTA Tuning panel.
  6. Daily Ion Chamber (IC) Checks
  7. Check that all ICs listed in the BAS (1-8) are active by verifying that each IC’s card in the Ion Chamber Card Chassis (111-903), location B062-0419, has its toggle switch down (“Normal”) and its top LED (“Output OK”) green. The cards are numbered on the face of the chassis.
  8. Ensure that the transparent cover of the Ion Chamber Card Chassis is closed and locked.
  9. Check the box on the Header in the NLCTA Operations Logbook that these checks have been completed.

Instructions for Completing Weekly Beam Containment Checks

To be performed each week when beam is first established.

  1. Perform the daily beam containment checks from the list above.
  2. Weekly Ion chamber (IC) Checks
  3. Select the IC channel number one (1) on the tester unit.
  4. Press the channel test button and slowly increase the test current with the “Current Adjust” pot until the IC trips. This may take a few seconds.
  5. Note the test current when the IC trips. If it is not equal to the trip setting as noted on the Weekly Beam Containment Checklist +/- 10%, note its trips value. Otherwise check the appropriate box on the Checklist.
  6. Repeat step 2.1–2.3 for channels 2–8. Channels 9 and 10 are not used.
  7. With at least one channel tripped, check that both modulator HVPS touch panels indicate a BCS fault and the indicated voltage (bar on left) is at or near 0.
  8. Check that the BCS LED on the Gun Trigger XMTR module, B062-4030-M8, is unlit.
  9. Initial and date the Checklist.

Weekly Beam Containment Checklist

IC number: / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
Trip threshold (nA): / 5 / 5 / 5 / 5 / 5 / 5 / 5 / 5
Initials / Date

November 14, 200702-03-07-R09Page 1