I propose some calibration runs for the upcoming Run 23, in order to ensure that we're not seeing any difference in distortions (or anything else anyone wants to look at?) between running the gating grid at ~2 kHz vs. 4 or 5 kHz (e.g. we aren't expecting ion backflow through the gating grid). We've raised the gating grid rate before, but I think it's well worth doing a test under the conditions we'll have for Run 23.

The proposed test set would consist of runs of only 25-50k minimum bias events each, enough to measure distortions, which really only takes a few seconds to acquire. Notably, all of these runs should be suitable for use in standard minbias physics analyses.

For a given beam condition, I would take either 3 or 5 runs in immediate succession, all with the same minbias trigger, modulo the GG rate limitation. Jeff Landgraf has informed me that it is straightforward for a trigger setup to be implemented with the rate limitation imposed via prescaling the triggers. The entire group of runs should take less than 10 minutes to acquire with the overhead of starting new runs each time:

1. 5 kHz GG, if it's available
2. 4 kHz GG
3. 2 kHz GG
4. 4 kHz GG
5. 5 kHz GG, if it's available

We have not had the 5 kHz readout available at the very start of Run 23, but I'd like to at least do the 4-2-4 as early as possible though and get that measured quickly.

Further, I want to see this test set conducted at different luminosities, and I expect the luminosity may not be maximum at the beginning of Run 23 either. So here's a more concrete proposal, where set C should be taken if the luminosities are raised to allow for rare (e.g. high pT) triggers:

1. Taken early in Run 23:
   1. a 5-4-2-4-5 set at whatever the maximum available luminosity is (perhaps 5-10 kHz ZDC coincidence rate?)
   2. a 4-2-4 set at about 75% of the maximum available luminosity
2. Taken a couple months into Run 23:
   1. a 5-4-2-4-5 set at whatever the maximum available luminosity is (perhaps 40-50 kHz ZDC coincidence rate?)
   2. a 5-4-2-4-5 set at about 75% of the maximum available luminosity
   3. a 5-4-2-4-5 set at about 50% of the maximum available luminosity (optional if we get beam down to 50%)
3. Taken deeper into Run 23:
   1. a 5-4-2-4-5 set at whatever the maximum available luminosity is (perhaps 80-100 kHz ZDC coincidence rate?)
   2. a 5-4-2-4-5 set at about 75% of the maximum available luminosity
   3. a 5-4-2-4-5 set at about 50% of the maximum available luminosity (optional if we get beam down to 50%)

I (Gene) will attempt to rapidly get results on each of these calibration sets to inform our operations during Run 23.

-Gene