April 15, 2010 FDC meeting
- Updates on:
- Full scale prototype
- Three-layer HV tests (Beni)
- Preparations for cosmics tests
Participants: Fernando, Eugene, Roger, Drew, Brian, Glenn, Mark, Kim, Simon, Beni, Lubomir
- The property at Blue Crab has been rented by JLab. Hall D will have to pay for our infrastructure inside the bay area, therefore it has to be planned carefully (Eugene).
- We discussed different options for the wire stringing. The main criteria we use to choose the right one are: demonstrated capabilities of producing operational wire frames, cleanliness of the facility, efforts required to adapt to machines for our purposes. The IUCF doesn't satisfy the above. For now the plan is to investigate the option of using the UVA equipment and expertise to set-up wire stringing at JLab. By chance, Drew and Brian will be at UVA tomorrow (presenting their new Si-detector for medical purposes) and were interested in looking at the UVA wire stringing equipment. Brian expressed the interest of the Detector group to investigate the possibility of having a JLab wire winding facility and one option would be to refurbish the SSC winder, now at JLab. Most of the participants asked questions related the modifications needed to have the machine operational. These modifications need to be evaluated and compared to the ones for the UVA stuff.
- Electronics: the PCBs are finalized (everybody is encouraged to look at the drawings linked above) and the procurement procedure will start very soon. Fernando explained the procedure, we are going to order 28 boards of each (for 28 wire planes, which includes 4 spares). Kim will send out the PCB specifications to three vendors for preliminary quotation; at the same time she suggested to have a meeting with the procurement people to make sure all the requirements are met. Everybody agreed on that.
- Cathode redesign: Roger addressed several questions (demonstrated with a drawing) related to the cathode daughter board (flex) design: ground around, width of the soldering area. Roger will implement Fernando's suggestions and we will discuss them again on the next meeting.
- New design mechanical prototype: includes wire frame and cathode-ground-cathode sandwich and was tested for leakage. We were able to bubble it at as low as 5 cc/min. This success means we will go with this design for the final chambers.
Full scale prototype
- For the first time, the three layers are assembled and are bubbling at 210 cc/min. The trick is to make the pressure similar in all the layers, to minimize the leakage between the chambers.
- Casey made 55 fixes on the wires of the top (third) layer; 5 wires were not reparable (without replacing them). Beni did HV tests on this layer: one sector doesn't hold the nominal HV, the other sectors can be used in the tests, especially the two side sectors, showing very low noise.
- Chamber preparations for the cosmics test continue. Mark mounted the holding brackets. Before installing the chamber at the test set-up tomorrow (Friday) morning, we will do one more test inside the tent: for leakage when the chamber is lifted and hold only on the brackets.
Beni got an offer from Frank Wesselmann to have two undergraduate students for two weeks in June and asked for a possible work for them. Lubomir will contact Frank.