BTA guidelines

Beam time accounting guidelines (based on Mark D's proposal in Run planning notes, Feb 2, 2018)

Accelerator beam time

• ABU: acceptable beam used (eg harp scans, calibrations, trigger settings, running)
• BANU: beam acceptable but not used (eg radiator change or our problems)
• BNA: beam not acceptable (eg tuning, drifting, not focused)
• ACC: accelerator configuration change (does not really apply to Hall D)
• OFF: no beam time was scheduled for us

Experiment beam time

• ER: experiment ready
• PCC: planned configuration change (when beam is masked while radiators are moved, etc)
• UED: unplanned experiment down (unpleasant surprises, hardware failure, extended daq issues)
• OFF: no beam time was scheduled for us, eg scheduled maintenance

When the BTA information is loaded from epics it contains automatic calculations of accelerator beam time from beamline monitors and 100% UED experiment down. We have to change or confirm this for each hour. Even if it is correct, each hour has to be 'edited' and saved.

The hour indicated in the leftmost "Hour" column of the table is the time when the hour started, that is, "19" would mean the hour that started at 7pm and ended at 8pm.

Guidelines

The shift leader should ensure that the accelerator side of the timesheet is consistent with ours. OFF hours indicate that no beam was scheduled for us - these can be copied from the accelerator side to the Hall D side.

For other hours:

Hall D side of the time-sheet
First we estimate time spent in UED (hopefully 0) and PCC (configuration changes). Then ER is 60 minutes - (UED+PCC).

Accelerator side of the time-sheet
The BNA value loaded from EPICS is usually reliable, so we can use this to calculate ABU = ER - BNA. If the beam is unavailable then that is counted as BNA, regardless of whatever we are doing (eg PCC).

BANU should equal the total time when no beam was requested, BANU = 60 minutes - (ABU + BNA).

During physics running, ABU + BANU should be the duration of good quality beam delivery.

During initial setup following beam restoration, the beam quality is not so critical, so beam-time spent checking radiation levels and harp scans etc should be counted as ABU.

Total time should be estimated without spending excessive time on it. Estimating this from myaplot/myaviewer when the beam is unstable is difficult.

If any PCC or UED time is recorded, the form will require you to use the Add button (beneath the timesheet) to add an explanation.

(The shift leader should also make a log entry at the end of each shift showing the stripcharts for beam current and position following our whiteboard instructions.)

Official machine time accounting user guide

Practical hints

The 'load from epics' button is a good starting point but its numbers are often incorrect.

The MCC crew chief shifts end 1h before ours. They need the first 7 hours of our timesheet to be completed very soon after the 7th hour of our shift ends. The departing crew chief cannot leave until after this has been done.

The 'save info for MCC' button has gone, instead, each hour has to be checked by hitting the edit icon (and edited if necessary) and then the checkmark at the RHS of the table.