FDC Weekly Meeting
Date: November 15, 2007
Participants: Daniel, Brian, Simon, Roger, Kim, Chuck
Next Meeting: November 29, 2007
- Everyone matrixed into our working on the FDC hardware aspects excluding Tim and Chuck have been provided with a detailed list of tasks and an associated time line for work until the end of June 2008. This is our internal deadline for completion of the construction of the full-scale FDC prototype. - DSC would like everyone in the group who has not already talked to him to schedule a brief meeting with him to go over the schedule to be sure we have an agreement on the list of tasks and the schedule. Please do this in the next few working days.
Composite Wire Frames
- The machine shop has nearly completed construction of the wire frame construction/alignment jig (which will ultimately become our package construction jig). This should be ready by the end of this week. - The construction of the 3 composite wire frames with the medium density Rohacell core will commence on Monday. The shipment containing our low density Rohacell core pieces is set to arrive at JLab next week. Construction on the 2 composite frames with this core then will proceed. - We discussed the issue of the possible "slop" in the positioning of the frames on the alignment fixture due to the use of plastic pins. A number of alternatives were discussed and we decided for now to replace 3 of our 24 pins with rigid steel "master" pins to ensure the alignment of the package stack layer to layer. - We discussed how to epoxy the dummy circuit boards together. DSC is in favor of painting epoxy along the full overlap region to give the strongest bond. Brian's original idea was to use a quick drying epoxy with simple tacks of epoxy along the joint. There was consensus that we want epoxy covering the full overlap region. - The detailed design of the supporting strongback has not advanced as of yet, but Brian has a pretty clear picture of what this will look like and the detailed design layout and associated drawings will take him no more than an afternoon. This work will take place after we make more progress in the construction of the composite wire frames. - Kim reported that one of the sets of fiducial sights on the dummy boards is not aligned with respect to the wires. These sights should be removed before winding to avoid confusion. - The order for our first 8-slot storage box is due into JLab next week.
- Weekly design meetings have been set up with Kim, Fernando, and DSC to go over the PCB design and address questions as they come up and to give feedback on the layout. Our first meeting was yesterday and there was a lot of good discussion of details that we were able to hash out and finalize. - The STB board design should essentially be finalized this month and then work on the layout of the simpler HVTB will commence. - Kim brought along drawings of the current STB layout and discussed recent progress and what her plans were over the next week or so. Our next design meeting will be held next Tuesday before the break. - We discussed briefly how we will make the HV connections to the HVTBs. The current idea is that wire pigtails will be soldered to the HVTB and end in a Reynolds-type low-profile connector. These connectors would be attached to a distribution board on the downstream face of each package where the connections to the mother cables would be made. Fernando suggested that we have the mother cable connect directly to the distribution panel with a single connector and then have connections to the individual pigtails at that point. We need to better understand what the HV connection options are and choose a connection scheme that is both robust and minimizes materials. We will return to consider this design in more detail after the holiday break.
- DSC has talked to the folks at IUCF. The budget that was prepared by the wire chamber lab has passed across the desk of the lab director and is now in the hands of IU procurement. We expect to get the budget shortly. - The current thinking is that the wire winding project will be opened up for bid. In preparation for this, DSC has prepared a detailed statement of work and it is on Elke's desk for review at the current time. When this is finalized, we will start discussions with the JLab procurement office. The time line for all of the paperwork is unclear, and it seems hard to believe that anything can happen before the end of the year. However, we will proceed as quickly as the system will allow us. - If we string at IUCF, we will have to construct a support system for the chamber frames to position them vertically for the wire measurement system. We will work on this design only after it is known where the work will take place.
Magnetic Field Tests
- Not much has happened on analyzing the data over the past week as Simon has been working on setting up the Test Lab and working on the Monte Carlo. Details will be reported when there is something to show.
Cathode Board Readout
- Roger showed a drawing of his planned design for making the connection between the cathode board and the daughter board connector. He has given his design drawings to an outside outfit called Innovative Circuits, Inc. They are reviewing the design. Once we process their feedback, we will work to order parts for a mechanical prototype to study the design.
- Bill was at CAD training this week, so there was no update on the design of the cooling system. DSC and Fernando will meet with Bill on Monday to have a discussion specifically on the cooling system. - Fernando will work to make some thermal images of the loaded daughter board to provide input to Bill's design. We also need to continue to evaluate the design from the standpoint of minimizing material while designing a system that can handle the expected heat load.
- Simon and Denny are working to restore our cosmic ray test stand in the Test Lab. They might even be able to start an acquisition run to check things out by tomorrow. Fernando is expecting to give us loaded daughter boards and interposer boards before the break next week. Fernando will talk to Joe about making cables for the tests so that they are ready when we are. - The second FDC Monte Carlo progress meeting took place just after the FDC meeting. Mark gave a talk on the inefficiencies seen within the current helix fitting algorithm. We discussed possible sources of the problem. Dave went over progress on developing a track finding code, first for single charged particles, and then for charged particles in a realistic background, and then also for multiple real tracks. The current work is ongoing for a beam-target luminosity of 102 photons/sec. He will work to get things working here before increasing the photon flux by an order of magnitude.
- Elke wants to have a meeting for the FDC system in December or possibly January to review the FDC technology choice. This meeting would most likely be with internal JLab experts. In order to be prepared for this review, we still have several important Monte Carlo studies that must be performed. This will be a priority for David Lawrence over the next month. We had a meeting with David, Mark, and Elke this week to go over the list of questions that need to be answer, a rough time line, and we identified the manpower to work on the various aspects of these studies. We will keep folks updated on progress. - This meeting and the results that come out of it are designed to help us better prepare for the formal FDC chamber review in March.
- The FDC short-term work list has been posted on the FDC web site (see http://www.jlab.org/Hall-D/detector/fdc/). This is continually being updated and DSC welcomes any feedback or comments from the group.
Minutes prepared by Daniel. Send any comments or corrections along.