...
Room F326 in F-wing at JLab
Agenda
Minutes
Present at JLab: Hovanes, Nerses, Krister, Stepan, F.X.
...
- 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 (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 20 um reproducibility25 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 the application 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.
...