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Room F326 in F-wing at JLab
Agenda
Wiki Markup |
[Description of motor applications for HPS|^StepperMotor.pptx] \ [Takashi\] Wiki Markup |
Update on ECAL HV/LV requirements \ [Stepan\]- Other business
Minutes
Present at JLab: Hovanes, Nerses, Krister, Stepan, F.X.
Present at SLAC: Sho, Takashi
Motorized applications
- Takashi described the HPS-specific applications requiring stepper motor control.
- Target (new stage)
- 2 foils and out position. May increase the number of foils to 5.
- 2 limit switches, low precisions, ~100um, always use reset with limit switch on power loss
- May need to put a wire on the stick for a harp scan after first chicane
- Collimator
- Target
- SVT motion
SVT scan- (new stage)
- 2 collimators and out position. May increase to 4.
- adjustable 50um, need to monitor some rates to find optimal position. Can implement a scan also,
- adjustment will need to be redone every time the collimator is retracted.
- Hovanes wanted to have specs of the stage (uni- and bi-directional reproducibility, accuracy, smallest increment)
- SVT motion (2 new stages)
- Nominal run positions and out position
- Support plates are horizontal in the nominal run position.
- Nominal run position need to have 25 um reproducibility.
- It would be good to have the specs for the stages to see how to achieve the reproducibility requirement.
- The encoder reset is suggested at the innermost end, but can be done at the outer position if the reproducibility is not compromised.
- The limit switch will be at 450um from the beam, the "hard stop" at 400um from the beam. The nominal run position at 500um from the beam.
- SVT scan (same stages as SVT motion)
- Two crossed wires on each frame. One horizontal, the other one at a small angle.
- The separation between the wires is on the order of a few centimeters at a vertical plane passing through the beam.
- Move the support plates individually and record the rates in some scalers. Find positions where the rates are identical to center the beam in SVT.
- The possible candidates for the detectors are a dedicated halo counter somewhere in the HPS setup or ECAL counters.
- The range of the scan, the speed of scanning needs to be determined depending on what detectors we use.
- Sometime in mid-September the description of these applications will be final or close to final.
- There are other motor applications as well: 2C21, 2C24, 2CH00, beam blocker. Total 8 motors for HPS: 2 on space frame, 6 near beam dump alcove.
Magnet Power Supplies
- Krister and Stepan discussed the magnet power supply controls
- We will need the power supplies for: Moeller quads, Tagger magnet, minitorus, Pair spectrometer.
- Krister pointed out that a lot of controls cabling, including magnet power supplies have been taken apart. This can potentially turn into a major headache.
- It might be easier to create new controls for some of them rather than to try to recreate what was there before.
- Stepan and Krister will go into the hall to see what is still there.
ECAL Voltages
- No update on ECAL HV/LV, the motherboards is still being finalized, and we ran out of time.