BLTWG Meeting 10/11/2007
The meeting was booked in VRVS on 11 Oct, from 10am to 12am (EST). Present for the meeting were Franz Klein, Yang Guangliang, and Richard Jones
Inventory of diamonds for CHESS run 11/2007
Yang has obtained the following diamonds that he can bring to CHESS for the tests in November 2007.
- Mainz diamond: 100 microns, 001 normal, 4mm x 4mm dimensions, very good quality synthetic Ib, several months of exposure to tens of nA with a beam spot 100 microns rms size.
- Element Six diamonds (four): 100 microns, 001 normal, 5mm x 5mm dimensions, synthetic Ib from stones of varying quality, some may be very good, no beam exposure.
All of the Glasgow diamonds are mounted in aluminum frames with a circular hole of diameter roughly 1cm. The diamonds are attached to the frames using gold-plated tungsten wires of diameter 30 microns or so.
For mounting the diamonds on the chess goniometer, Yang has purchased a optical mount with an azimuthal rotation adjustment. The post for this mount will be threaded to mate with the screw on the chi rotation stage of the C beamline goni. A picture of the optical mount is shown in the manufacturer's brochure, where we have chosen the 2-inch product. The picture below shows where this mount will couple to the existing goniometer.
| Close-up view of the sample mount, CHESS C beamline |
Glasgow will provide the custom mount for the individual diamonds to be studied during the 2007 run. Richard also requested that the mount include a cover that shields the sample mechanical stress from air currents. This should be thin enough that it does not produce X-ray background in the detectors, but it should also be mechanically stable so that it does not have persistent low-frequency vibration modes that shake the sample after each step of the goniometer. Yang will look into having some kind of covering constructed around the mount for this purpose.
Yang already has reserved his place in Fairfield house. Richard will make a reservation for himself and for the Glasgow student for the dates October 30 - November 6.
Richard will make contact with Ken Finkelstein and bring him up to date on our plans. He will find out the progress on preparation of the new Si(331) monochromator for use during the upcoming run.
Definition of the Tagger 100% Engineering Design
Franz asks everyone to take another look at the latest set of files on the tagger specification and documentation from the 35% design. For the specifications we are working from version 4 dated May 7, 2007. For the 35% design drawings and analysis report documents, these are in a state of some disarray at the moment. Some documents from the original set dated April 2007 are still current, while others are superseded by a new set dated May 2007. Yang and Franz will make sure that a single collection of the final documentation resulting from the 35% design and analysis work is assembled as a basis for the specifying what is entailed in the 100% design. Yang has agreed to set up a page on the wiki where all of these materials will be collected, together with the draft specification and statement of work document for the 100% design that has been put together by Franz.
Richard will look into the possibility of getting a private area of the wiki set up so that these materials are visible only to members of the GlueX collaboration.
