[Pi0tff] 3-experiments preparation joint meeting updated

[Patrick Achenbach]

Dear all,

I apologize for not following up earlier on organizing a joint meeting of the the three HyCal experiments. I wanted to get a clearer picture of the beamtime schedule and other boundary conditions before discussing with you a path forward. Please make another attempt to schedule a meeting.

You can find my considerations below:

- Beamtime request.

This is the topic which will probably produce the most headaches. Due to the necessary installations and changes of beamline, target, and detector, the experiments will be most efficiently scheduled from one SAD to the following SAD. Such a setting will minimize the loss of valuable beamtime.

As you know, each Program Advisory Committee (PAC) approved day is mapped onto two calendar run days. From SAD 2022 to 2023 we had ~ 96 PAC days scheduled, same for the period 2023 to 2024. You may have heard of the budget restrictions which forces us to extend this years SAD into November or later and to reduce the next running period from SAD 2024 to 2025 to approx. 80 PAC days. I have no guidance on how much operation time we will have in following years. The most optimistic scenario is ~ 100 PAC days. This means, we should consider 80-100 PAC days to be available in a first campaign spanning one SAD to the next.

The three experiments have been awarded the following PAC days:
PRAD-II: 40 total. 24 for production (three beam energies), 7 for calibration, 8 for empty target measurements.
X17: 60 total. 50 for production (two beam energies), 4 for calibration, 6 for empty target measurements.
piTFF: 67 total. 60 for production (10.5 GeV), 5 for calibration (5.5. GeV), 2 for empty target measurements.

This sums up to 167 PAC days plus the necessary time for setup changes. We need to discuss which experiments with which beam energies should run in the first campaign. While one could most optimistically assume 100 PAC days, one should be able to make efficient use also of 80 PAC days.

- Experiment readiness.

HyCal modules:
By now it is clear that no replacement of the lead glass with PWO modules will happen within the next year(s).

HyCal readout:
HyCal cables will be re-terminated and FASTBUS equipment removed. Production orders for 85 assemblies of Flash ADC 250Msps version 3 design have been placed several months ago, but the vendor has not yet built any boards. Priority for FADCs from this first order is for Hall A/C. Another larger order is pending approval due to the current budget limitations. While we should plan to have 72 FADCs available for the 1152 PWO channels by SAD 2025, there is no guarantee that 576 lead glass channels can be read out.

If experiments want to run in 2025-26, they should plan for using the inner HyCal only.

Target chamber, pumps, and cell:
The "PRad-II, X17 and TFF Tasks List" lists the JLab Target Group as responsible for these items. This is a misunderstanding. The Target Group is not responsible and do not have the resources for taking this responsibility. Hall B has the ownership of this target. We are hiring a new systems engineer for target-related work, starting in May, who could possibly provide help in design/engineering. We are also in the process of hiring a technician for target-related work. For both positions the priority is the Polarized-Fusion Project, and work on PRad equipment can only be done if time permits.

Scintillating detector:
The Target Group will not work on that detector and its integration into the target. I have assigned Youri Sharabian to this project and he has a conceptional design.

GEM chambers:
The contract with UVa was awared and fully executed end of March 2024.

Experiment Readiness Review:
Before a scheduling request can be submitted, the ERR needs to be passed, at least on year ahead of beamtime. At this stage the fabrication of the equipment should be completed or near-completion. As the experiments are not yet ready to call for an ERR, we should discuss this.

Best regards,
Patrick
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