Addressing ERR review recommendations

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Charge 2: Has the detector been completed, commissioned and ready to operate? If not, what are the completion/commissioning schedule and tasks?

  • Recommendation 1: The schedule for DIRC installation and testing before the hall closes for GlueX operation is extremely tight. The installation plan should be carefully evaluated to ensure that it can be safely completed in the allowed time. An alternative plan for commissioning and testing should be developed in case installation and commissioning are not completed on time.
    • MIT-Bates continues to provided updates weekly on optical box fabrication status.
    • An alternative installation plan was developed for an initial mechanical installation of the Optical Box in Hall D August 13-17, and successfully completed.
    • A detailed schedule of work for Optical Box component delivery and testing is in place
    • The internal mirror box was delivered to JLab on 9/19, and testing of the mirror optics was completed in the Fall.
    • The final components of the fused silica window and dark box enclosure arrived in early January and December, respectively and the complete Optical Box system in Hall D is expected to be installed before the Spring 2019 run begins.
  • Recommendation 2: List all of the goals and milestones for successful commissioning.
  • Recommendation 3: The magnetic field on the PMTs and magnetic shielding were concerns raised in the 2015 review (Technical comments 23 and 24). The results were not presented to this review. The committee recommends that those comments on the previous review should be addressed.
    • The magnitude of the field in the PMT region which is transverse to the PMT plane orientation is ~15 G (from Eugene's calculation). Previous studies of the H12700 indicate that this would cause a ~15% loss of efficiency in some pixels near the edge of the PMT (Summary slides and full paper).
    • Testing of our DIRC PMT response in magnetic fields up to ~35 G (Longitudinal and Transverse) in TEDF setup is complete. Results are consistent with expectations for edge pixels

Charge 3: Have all the tasks needed to safely mount and operate the detector been identified and defined adequately?

  • Recommendation 1: Provide an evaluation of the cooling requirements and confirm that the cooling will be adequate. If the cooling is not adequate produce an updated schedule that reflects the steps needed to provide a system that can be reliably and safely operated.
    • The power dissipated by each module is ~4 Watts, so the total in one optical box enclosure would be ~144 W.
    • Require FPGA temperature remains below 80 C, which likely requires temperature inside dark box enclosure remains below 50 C.
    • See this logbook entry with details of the heat load test up to 415W (3x the expected load), and demonstrated the cooling requirements are met.
  • Recommendation 2: Water quality requirements and monitoring are necessary, should be carefully studied and a procedure documented.
    • Water quality plan developed and approved, with periodic analysis of samples for trace contaminants and pH as well as dissolved gases.
    • Beyond Fall 2018 commissioning: consider dedicated in-situ transparency measurement to track quality vs time (not required for initial commissioning).
  • Recommendation 3: The procedure for integration of the DIRC into the GlueX DAQ has not been presented. A detailed plan for integrating the detector into the DAQ system should be developed. Similarly the integration of the DIRC into the slow control system was not thoroughly documented.
    • The DIRC SSP modules have been installed in a VXS crate on the downstream platform and have been successfully integrated into the standard production trigger by Sasha Somov
    • Two modules were successfully read out and parsed with the Hall D offline software: logbook
    • Final integration tests with the DAQ will be performed in November after the full installation, and in conjunction with the initial commissioning steps
  • Recommendation 4: Provide the projected background rate during high luminosity running and show the signal can be separated from the background.
    • The expected background rate at the highest beam intensity is an average of ~5 kHz per pixel, which is tolerable since the ~1 ns timing resolution will reject potential the vast majority of these background hits.
    • Using the Look-Up-Table algorithm for studying the π/K likelihood distributions, two simulation samples of 4 GeV pions and kaons were compared: one without any background and one assuming electromagnetic background from the 300 nA electron beam for high intensity running. Below are plots of the likelihood difference between the π and K hypothesis where clear separation power is observed even after background is added to the sample (bottom plot). This clearly demonstrates the signal photons can be differentiated from the background, under this model of the electromagnetic background.
π/K separation without background
π/K separation with high intensity background (300 nA beam current)

Charge 4: Has the detector ownership, maintenance and control during beam operations been defined?

Charge 5: Are the responsibilities for carrying out each job identified, and are the manpower and other resources necessary to complete them on time in place?

  • Recommendation 1: The optical Box delivery is the critical path for this installation. A contingency plan for late delivery needs to be available as well as an independent verification of the status of the Optical Box.
    • See Charge 2 Recommendation 1.
  • Recommendation 3: Clarify which manpower is provided by non-JLab and JLab groups. Verify that the manpower and other resources will be available if the installation and/or commissioning schedule is changed.
    • Manpower for PMT installation and initial detector checkout is provided by non-JLab groups which are available both Optical Box test in October, installation in November, and commissioning in December:
      • JLab: Hall D technicians and electronics group
      • W&M: Justin Stevens, Wenliang Li, and Andrew Hurley (local)
      • MIT: Yunjie Yang and Maria Patsyuk
      • CUA: Greg Kalicy
      • GSI: Joe Schwiening, Ahmed Ali, and Roman Dzhygadlo (during commissioning run.

Charge 6: Are the specific documentation and procedures to operate safely and efficiently the detector, in place and adequate? This includes initial operation.

  • Recommendation 1: Complete maintenance and operational Documentation including completion of OSP
    • The DIRC OSP was submitted and approved.