Private:Weekly Group 7/23/2008

= Minutes =

Carl's Update

 * BNC feed-through panel for the dark box finished and installed. Light test showed transmission through the dielectric layer, but is easily sealed with terminators or tape.
 * Technique being developed for gluing scintillating fiber segments to waveguides in large batches. A small alteration to the existing apparatus should allow gluing of all 25 fiber pairs simultaneously. The five members of each row will also bond to one another. (Teflon tape will be used between each row-stack so that the fibers can be manipulated separately in units of 5-channel rows and then staggered as necessary in our apparatus in a later gluing session or compressed together in the modules under design)
 * After more testing of the microscope, it seems that it's definitely some inherent problem in the camera hardware. Perhaps it's more worthwhile to design a way to attach a commercial digital camera with optics taken out so that the existing optics project straight on the CCD.

Igor's Update

 * Experimented further with Root, but problems persist with fitting. Despite following tutorials, the fitter doesn't quite get the handle on the fit parameters as they are returned unchanged at the end of the minimization search.
 * Looked into the Tagger signal output interconnect and overall backplane layout. Simple BNC turned out to be the best way to go given the price, fast disconnect and availability.
 * The (previously discussed) literature search on the HPD anomalous response was made and a documented phenomenon known as "ion positive feedback" was found. Apparently electrode geometry was being investigated in late 90s that blocks ejected ions from accelerating back to the photo-cathode. Spectral analysis was not found in those papers, however.
 * Some time was taken up by discussion of the Stats Cluster quotes.

Woody's Update

 * We discovered how to route the high voltage DAC outputs to the second row of pins in the Eurocard connector
 * The solder pad size for the Eurocard connector can be reduced to 62 mil, per the manufacturer’s data sheet, allowing 4 mil high voltage traces to pass safely through
 * This will allow us to use a 48-pin (3 rows x 16 pins) Eurocard connector rather than the existing 64 pin connector
 * The PCB will now be rectangular, because the Eurocard connector will no longer be wider than the rest of the card.
 * The JTAG connector will be moved over roughly 100-200 mil to allow further size reduction of the PCB
 * Traces will be rearranged to allow channel 31 of the DAC to be voltage divided and measured by the ADC
 * Igor drafted a tentative design of the connections on the backplane
 * We determined the digital and analog board connectors must be adjacent to one another rather than overlapping, due to clearance issues
 * The analog board will need minimally a 2 row connector, though perhaps not of the Eurocard type (a single row connector would result in too many unroutable connections due to the 2 rows of high voltage from the digital board)
 * We examined available coaxial connectors to determine the best method of routing analog signals off the backplane – under consideration are BNC, SMA, SMB, and others. (See Igor's note.)