David S. Armstrong
William & Mary

• Arrival of Dominic Martin Grimm
• G10-Frames for chambers: We have had to change from our original design material (Stesalit) as the company no longer manufactures this, to G10 (but non-brominated, halogen-free).
  Two companies bid on the project; a fixed-price contract was awarded April 30 to Atlas Fibre (Skokie IL) who will do the machining and quality-control of the frame parts. Cost is $87 K (the other bidder was 50% higher), which is somewhat less than what the Stesalit + machining costs were expected to be.
  There are a total of 160 individual parts, of 14 different types, with varying thicknesses, lengths and machining (holes, O-ring grooves) required, so it is not a trivial job. Delivery in 8 weeks according to the contract. The frames will be machined in pieces (either 92.5 in long or 33 in long) which we will epoxy together here at W&M. They will send us the scrap material form the initial rough cuts for us to do gluing tests and flatness measurements.
• Wire stringing jig has been machined at W&M with the new CNC mill, See: Photos of stringing jig.
• Lots of progress on electronics; Klaus and I are meeting biweekly with Fernando Barbosa (JLab engineer), who has enlisted Kim Shinault (Electronic Design Drafter) and Jeff Wilson (Electronic Tech) on the project.
  1. LVDS to ECL converters. These come ater the MAD-chip based preamp/discriminator cards, but before the multiplexing.
     Status: chip's selected, schematic done, initial board layout done, final board layout should be ready for prototyping in 2 weeks, initial cost estimate done ($315/board; will need 70 boards for full system). Will make a couple of prototype boards for testing before full production.
  2. Multiplexing scheme.
     We will use a digital delay-line scheme in which ECL hex gates are used as the delays (1.3 ns/step). This will be implemented on the backplane of a VME-style crate (9U DIN powered chassis).
     Status: chip's selected, first draft schematic done. Expect completed schematic in 2 weeks. Power supplies defined and costed.
  3. Preamp/discriminator.
     MAD chips were purchased many months ago, and have been tested. We have had conceptual discussions on the preamp boards, but have this lower on our priority list for the electronics group. We have working MAD chip boards for testing purposes.