Technical Board Meeting April 10, 2023

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Online:

Agenda

• Ciprian Gal - Beamline Change: Adding Harp to Compton Beamline. DocDB:1042
• Ciprian Gal - Stripline vs 20cm BPMs in Hall A line DocDB:1043
• Accelerator Task List for MOLLER (Task list: DocDB:1046) (Summary of beam requirements: DocDB:403)
• Discussion of future agenda topics

Minutes

• Request to add harp to the straight-through Compton line, which will aid in verifying or correcting beam match optics for control of Compton backgrounds and transfer function / matching concerns for the MOLLER optics
  • Either directly over the IP in the Compton laser hut, or upstream of the Compton laser hut on the section between chicane dipoles 1 and 2.
  • no concerns on radition.
  • prelim budget ~ $25k
  • TB agrees this is useful, will make beam setup more efficient and more robust. No concerns expressed.
• BPM
  • Decision needs to be made between two types of bpm hardware: the well-known "20cm" or "thin wire" bpms used previously in Hall A, or new "stripline" bpms which are a couple cm shorter and have machined antenna.
  • Beamline SRD inconsistent, with a table specifying "20 cm" bpms but the figure (and current beamline design) using stripline bpms.
  • Unclear whether new striplines can be used with old SEE electronics, or only new digital receivers (DR)
  • There is a strong feeling that it is important to benchmark new bpm receivers using the well-known SEE electronics.
  • If striplines can use SEE, then the current design is ok. If not, MOLLER would like to replace BPM 1H04 and BPM 1H14 with 20cm. Or BPM 1H11/1H14, if that is easier.
  • Further discussion of electronics in "NPFA" (fire protection areas inside the partially enclosed hydrogen target bunker. It was decided that it probably is not a problem with regard to BPM electronics, if they can be located outside the bunker, and also that the beamline intruded in the target NPFA regardless of what we do with the stripline vs wire bpms.
• Accelerator Task List - This is a document that Accelerator Division is putting together to plan for meeting the specific requirements listed in the MOLLER beam requirements document. It aims to list separate tasks or topics with enough detail to estimate the required scope of work but otherwise to be relatively general. It isn’t so much documentation as it is an outline or working note for planning purposes. The TB members should glance through for any issues they care about, and send comments or suggestions.
  • Dave A asked about the DR readout for the cavities (task 19 was about new BPM receivers), and specifically about preserving the low current capability.

Attendance

• Kent Paschke, Chair (MOLLER Scientific Coordinator)
• Krishna Kumar (MOLLER Spokesperson)
• Mark Pitt (Deputy Spokesperson, MOLLER-NSF Project Coordinator)
• Michael Gericke (MOLLER-CFI Project Coordinator)
• Mark Jones (Hall A Leader)
• Paul A Souder (Elected Executive Board Member)
• David Armstrong (Elected Executive Board Member)
• Robin Wines (Project Engineer)
• Dave Meekins (L2 CAM: Target)
• Mike Dion (L2 CAM: Spectrometer)
• Ciprian Gal (L2 CAM: Infrastructure)
• Robert Michaels (L2 CAM: DAQ)
• Vladimir Berdnikov (L2 CAM: Installation)
• Silviu Covrig (Working Group Convener: Target)
• Caryn Palatchi (Working Group Convener: Polarized Beam)
• Dustin McNulty (Working Group Convener: Integrating Detectors)
• Paul King (Working Group Convener: DAQ)
• Jim Napolitano (Working Group Convener: Polarimetry)

Absent:

• Jim Fast (DOE Project Manager)
• Jessie Butler (Deputy DOE Project Manager)
• Juliette Mammei (Executive Board International Representative)
• Carl Zorn (L2 CAM: Detectors)
• Nilanga Liyanage (Working Group Convener: Tracking Detectors)
• Rakitha Beminiwattha (Working Group Convener: Simulations)
• Yury Kolomensky (Working Group Convener: Physics Extraction)