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Cornell High Energy Synchrotron Source

Doc#: REF-OPS-003

Procedure: CHESS Operational Modes

Prepared by: KM

Rev.: 3

Revision Date: 02/14/15

Date Effective:

Date Expires:

Approved by:
  1. To provide brief descriptions of the different operational modes of CHESS
  2. To describe the CHESS Operator’s role during shifts for each operational mode
Operational Modes
CHESS Running
  1. When is CHESS in a “running” mode:
    1. CHESS is in a “running” mode when there is user beam available. The days before users arrive are considered the start-up of “CHESS Running,” when stations are being aligned and CHESS Staff are preparing for users. The CHESS Running periods usually last for about 4-12 weeks at a time, three times a year.
  2. What is the status of CESR in a “CHESS run”:
    1. CESR runs e- and e+ user beam 24/7 during a CHESS running period, except for on scheduled Tuesday access days. User beam will end at 7am Tuesday, and there will be open tunnel access from approximately 8:30am- 2pm Tuesday for tunnel inspections and repairs to take place. At 2pm CESR will close up the tunnel and do machine studies and prepare for CHESS conditions. User beam generally is available again at noon on Wednesdays.
  3. What is the role of the CHESS operator in a “CHESS run”:
    1. When CHESS has user beam, the CHESS Operators are on staff 24/7. CHESS Operators may begin shifting during the start-up period when the stations are being aligned and CESR is processing the machine.
    2. The CHESS Operator on shift will communicate with the CESR Operator on shift and relay that information to users, if necessary. The CHESS Operator will check in with users frequently and make announcements when runs are beginning and ending. The CHESS Operator will help users any way needed (or notify other staff to help) and also assess and handle any other issues that arise on shift.
  1. When is CHESS in a “down” mode:
    1. CHESS is in “down” mode when there is not user beam available for an extended length of time, usually 3 weeks or more. There are no users at CHESS during this time.
  2. What is the status of CESR during a “CHESS down”:
    1. CESR is usually not running during a “down” period. If CESR is shut down for an extended length of time, the tunnel will be in open access. “Down” periods are an opportunity to complete more involved projects and maintenance in the tunnel.
  3. What is the role of the CHESS Operator in a “down” period:
    1. CHESS Operators will only have “aux” shifts during a down period – there will only be an operator on shift from 8am-4pm, Monday-Friday. Operators on aux shifts can usually work on other projects, since there are usually not users at CHESS during down times. The operator should still carry the pager and respond to any alarms.
    2. One line key from each beamline will be in a locked box at Ops during the down time.
  1. What is a CESR-TA Run and when do they happen:
    1. CESR-TA stands for Cornell Electron Storage Ring – Test Accelerator. Individuals who work in the CESR-TA group design experiments that require special equipment to be set up in the C1 and D1 hutches. The CESR-TA runs usually last for 1-2 weeks and typically occur immediately after a CHESS run.
  2. What is the status of CESR during CESR-TA:
    1. CESR is running during CESR-TA to provide e- or e+ beam to C1 and D1.

  1. What is the role of the CHESS Operator in a CESR-TA run?
    1. CHESS Operators will only have aux shifts for CESR-TA runs. The CESR-TA “users” (who are employees at Wilson Lab) will communicate with the CESR operator without going through the CHESS Operator. The aux shift operator during CESR-TA runs may need to check the water levels in chillers at C1 and D1, but does not need to get much more involved unless needed. Operators may also be asked to help move equipment into and out of the hutches when CESR-TA set-up is taking place.
Revision History
Rev. 1 – Initial document 5/24/12 KM
Rev. 2 – Changed time for open access on Tuesday mornings. 6/8/12 KM
Rev. 3 – Removed reference document for User Communication that is obsolete now. Added header and page numbers (2/14/15 KM)

-- LeeShelp - 21 Apr 2017
Topic revision: r1 - 21 Apr 2017, ljs30
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