FDC Weekly Meeting
Date: October 8, 2009
Participants: Daniel, Beni, Bill, Simon, Fernando, Mark S., Mark I., Casey, Stephen, Roger
Next Meeting: October 22, 2009 @ 1:30 p.m.
General Construction Updates
- We are presently gearing up to begin stack construction for the full-scale prototype starting in the first part of next week. We will initially construction a single cathode-anode-cathode layer (using the two cathodes attached to our end gas windows) and work on measuring and eliminating gas leaks. The plan is to perform a 3D voltage check with in an Ar-CO2 gas environment with the chamber at nominal plateau voltage to be sure that there are no breakdown problems. Fernando will have a cathode and an anode preamp board available for us to check some signals on the scope. Stay tuned for details. We may have the opportunity to verify some of the crucial design features of the detector in terms of signal to noise levels next week. - The preliminary FDC stack assembly document draft is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. The document will be fleshed out during the assembly procedure for the full-scale prototype. - Tom Carstens has been working on moving the clean tent from the EEL building clean room to EEL 126. The move is nearly done. Due to the size of the clean tent, we are still finalizing the reorganization of EEL 126 and working to put a few things into storage until they are needed. The clean tent should be fully sealed by the end of this week. We will turn the air flow on shortly and make the tent clean in preparation for stack construction. Mark S. will find a particle counter to verify that the tent is sufficiently clean for construction. The fan speeds on the clean tent are adjustable and Mark S. will talk to Jack Segal for information on proper settings.
Wire Frame Update
- Wire frame P1 status: * During handling on Friday of last week, 3 wires were broken on the frame. They have been repaired and the frame is ready for final electrical QA checkout and connector gluing. This work will take place today or tomorrow as P1 is the first frame needed for stack assembly. The frame will then ready for lamination to its cathode plane. This lamination will take place either tomorrow or Monday. - Wire frame P3 status: * This frame is ready for final electrical QA checkout and connector gluing before lamination to its cathode plane. All Snoop-related problems have been mitigated and DSC will pay off Fernando as soon as he can raise the cash. - Wire frame P4 status: * After sitting in an Ar/CO2 environment for 4 more days, frame P4 is feeling much better. All busses are below 30 nA except for one which is at about 80 nA (but was improving with conditioning). This frame is essentially ready for final electrical QA checkout and connector gluing before lamination to its cathode plane. A couple of other minor operations are neede on P4, replacing two capacitors, filling in of a joint between the left HVTB and the filler board, and coating with the humidity sealant. - We need to have a dedicated meeting to design what the schedule for work on the Phase 3 wire winding will be. The highest priority for work scheduling will be doing work on upgrades of the wire winding facility. This includes a better strongback design, the design and construction of precision combs, modification to the wire winding table, and a list of other items with the system. Stay tuned, more to come. - The wire frame construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. We will include the information on the wire electroplating process shortly. - The parts of the jig to use for the wire electroplating operation are in our hands. They will be assembled as we find time.
- Progress updates: * Fernando is overseeing the QA electrical tests on the rigid-flex assemblies. We should be able to get another set or two delivered next week and all available boards by the week after next. * We do not have enough rigid-flex assemblies due to yield losses on the original order of 60 (54 are needed for the prototype). Roger will finalize the order today and we expect to have the remaining boards in our hands within 2 weeks. The order will be for ~25 boards. * Fernando has certified the soldering procedure of Mark S. and work has begun soldering the rigid-flex assemblies to the first cathode frame for stack assembly. Four boards have been attached but still need electrical QA. The work is taking longer than Mark S. expected as the procedures are still being tweaked. Ultimately we expect to a single cathode frame will need about 2 days for all flex assemblies to be attached. The soldering work on the first cathode should be done tomorrow if all goes according to plan. - The current draft of the cathode construction document is located at: /u/group/halld/Engineering/PRELIMINARY DOCUMENTS. - Roger has been discussing packing of our cathode material for delivery to JLab. - Roger needs to prepare a document for QA/stuffing/cleaning for the cathode boards and a similar document for the cathode daughter boards and ground boards.
Cosmic Ray Test Stand
- Beni is continuing work to setup the cosmic ray telescope and test system in EEL 126. He has been working on getting the IU chambers into the readout. He has taken some data, adjusted the geometry alignment parameters, and is trying to make sense of the data correlating the IU chamber coordinates with those from the small-scale prototype. The latest plots are in the FDC electronic logbook at: http://www.jlab.org/Hall-D/detector/fdclog/ - We still have some mysterious behavior with the small-scale prototype response with wiggles in the X vs. Y distributions that need to be understood. Beni has gotten a larger data set on the small-scale prototype and the wiggles are still present. There seems to be a high-frequency wiggle and a low frequency wiggle. See the FDC logbook for plots. - Beni has started a bench test plan for the full-scale prototype and is presently working on it after incorporating feedback. The current information is contained on the FDC wiki page under the heading "FDC test cosmic ray test stand".
- Fernando reported that the issues with the ASICs seemingly having problems with their linearity are not as bad a first thought. Optimizing the components mounted on the preamplifier boards was the cure and we will not have to wait for a new order! Fernando will have preamplifier boards for our single layer voltage checks available next week.
- The FDC short-term work list has been posted on the FDC web site. 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.