Revision as of 12:04, 19 August 2014

This page gives the run plan for the Fall 2014 commissioning. It is a controlled document that can be edited only by E. Chudakov, E. Smith or A. Deur. Suggestions and comments should be send to them.

Items in pink indicate missing information.

General Information

This document describes the run plan and procedures for the Hall D Fall 2014 commissioning.

• Goals for the Fall 2014 run (expected durations are given in parenthesis)
  1. Clean tune of the electron beam into the Tagger Dump (15 days)
  2. Commissioning of the unpolarized photon beam (4 days)
  3. Commissioning of the Hall D equipment under "soft" conditions (17 days):
     • Low-intensity unpolarized photon beam <10 MHz/GeV at the endpoint
     • Thin solid targets instead of the regular liquid hydrogen target
     • Solenoid current 1200 A instead of the nominal 1300 A
• Schedule and Hall Availability: The accelerator run is scheduled for 19-Sep-14 - 22-Dec-14. 3 week are assigned for Hall D commissioning with photon beam (see [1]). The tentative plan is:
  1. Accelerator: beam recovery and 5.5 pass beam tune to the dumplette Sep 19-29. Hall D/Tagger are open.
  2. Accelerator: electron beam tune to the Tagger Dump, 29-Sep-14 - 03-Oct-14. Hall D/Tagger are locked. TAGM and the electronics are removed from the Tagger Hall.
  3. Accelerator/Hall D: Photon beam tune to Hall D and the initial equipment checkout, Oct 4-7. Halls are locked.
  4. Hall D: Re-installation of the Tagger equipment (TAGM and the electronics), Oct 8-13. Halls are open.
  5. Hall D: Equipment commissioning with photon beam, Oct 14-31. Halls are locked.
• Expected Staffing and responsibilities:
  • The Run Coordinator (RC, Alexandre Deur) oversees the commissioning.
  • The Physics Division Liaison (PDL, Yi Qiang) and Hall D Work Coordinator/Safety Warden (T. Carstens) verify that the proper safety rules are followed.
  • The Analysis Coordinator (TBD) will organize the off-line analysis effort.
  • Individuals responsible for each commissioning step are named in the section describing the step. They are also responsible for logging in the ELog the summary of how the step proceeded and other relevant information.
  • Shifts
    • Online Shifts (Nominally 3 persons per shift, one with solenoid training.):
      • Electron beam commissioning: Shifts will be scheduled but be stand-by shifts by default. The counting room will be manned only if accelerator needs a contact, or if Hall D expertise is needed to support the beam tuning (e.g. to operate the amorphous collimator harp). If so, the shift leader will be asked to be present. If the task demands it, the two-man rule must be obeyed.
      • Photon beam commissioning: Only beam line equipment and the solenoid will be operated. The detectors will be turned off for most of the time, with the possible exception of BCAL and the outer rings of FCAL. The counting room will be manned by two shift persons, one with solenoid training, and the experts necessary to the conduct of specific parts of the run plan. The RC will assign the experts. The third shift taker will be on stand-by.
      • Initial detector testing with the tagger equipment still removed: Once the photon beam is commissioned the Hall D detectors will be turned on, Online shifts will be operated by three persons, one with solenoid training.
      • Re-installation of the tagger equipment: Shifts are on stand-by.
      • Detector commissioning : Online shifts will be operated by three persons, one with solenoid training.
    • Offline Shifts: at least two people looking at the data taken. (Offline Shifts are organized by the Analysis Coordinator)
• Coordination Activities:
  • The RC will attend the MCC meetings at 7:50am and 8:00am and the weekly MCC meeting (Wednesday, 1:30pm). The PDL will attend the weekly MCC meeting.
  • Daily run meetings broadcasted on Bluejeans will occur at 10:30am in the counting house conference room. The Analysis Coordinator will be responsible for organizing and chairing the meeting.
  • Links to accelerator schedules:
    • CEBAF 12 GeV Commissioning calendar
    • Scheduled Accelerator Down (SAD)/Maintenance Calendar
    • http://accboard.acc.jlab.org/
• Activity Priority
  • High: Activity should be completed, contingencies in place for issues.
  • Medium: Desirable to complete the activity.
  • Low: Activity would be useful if time permits us to do it.
• Activities planned for the next run in Spring 2015:
  • Installation and operations of the liquid hydrogen target.
  • Installation and operation of diamond radiators in goniometer.
  • Running at 1300A solenoid current.

Beam Configuration Parameters

• Energy of Beam: expected ~ 10.5 GeV
• Beam current:
  • Electron beam tuning is done with pulsed beam 4-10 µA, duty cycle 1.5%, average current 60-150nA (see beam description here)
  • Photon beam operations: CW 50-200 nA
• Radiators:
  • 1.5 µm Al (1.7·10^-5 R.L.)
  • 10 µm Al (11.2·10^-5 R.L.)
  • 30 µm Al (33.7·10^-5 R.L.)
• Collimator hole: 5 mm diameter
• The commissioning targets are disks of 3.19 cm diameter. Only one disk can be installed at a time. The z-position of a disk can be moved 12 cm downstream to 32 cm upstream relative to the nominal Hall D cryotarget center (60 cm downstream of the downstream end of the upstream solenoid end-cap). The available disks are:
  • 10mm thick disk of CH₂ (HDPE, high density polyethylene, density 0.93-0.97 g/cm³ ), 0.95 g/cm², ~1.2% R.L.
  • 2mm thick disk CH₂ (HDPE)
  • 2mm thick inside a 20mm diameter area and 7mm thick outside (HDPE)
  • 3.4mm thick graphite disk, 0.75 g/cm², 1.8% R.L.
  • Al. cross made of 1.59 mm diameter wires
  • 1cm long Al. cylinder with an equilateral triangle hole inside. The triangle edge lengths are 2.5 cm

Run Plan

Tune Electron Beam

Tune Photon Beam

One Week Pause in Running

Collect Beam Data for Detector Checkout

Optimize Detector Settings

Drift Chamber Alignment

Collect More Regular Data