Chair: John Payne
Attendees: Baryshev (SRON), Brown (NRAO), Carter (IRAM), Ellison (RAL), Harman (RAL), Lamb (OVRO), Payne (NRAO), Rafal (NRAO), Wade (ESO), Webber (NRAO), White (NRAO)
The design is on-going. Lamb is writing up a selection report, which will include author contributions on different designs on the band. Baryshev sent out information on the band he is working on. Carter has sent out information on what he has done as well. Carter has made a graphical representation of what the group decided at the Optics meeting in Tucson. As requested, Carter will re-work the design to give a top view which will show the cartridges. Lamb confirmed that the water vapor receiver pick-off mirror will be in the center.
No final calculations have been made yet. Need more information on deflections. The mirrors will be mounted outside the dewar. Much discussion ensued on deflection possibilities.
Payne received lots of response on the widget list he sent out. Most agreed on the ambient temperature load. Items listed as options included: semitransparent vane and quarter wave plate. Lazareff is working on this. A suggestion to drop the quarter-wave plate was brought up. This is not a real science issue.
In Munich on November 30 there will be a meeting to discuss the challenges of moving from building lab state-of-art items to production items. Invitations have been sent out to 15-20 people. A draft agenda will go out next week. Comments were asked for. It was agreed that this is a good meeting. There were several ideas given on how this should be obtained. Rafal stated that it would help the meeting progress if, beforehand, there are statements about how the different centers (distributors, etc.) would be defined. Wade explained that the intent of the meeting is for the group to develop a draft overall strategy for this process. Payne was concerned that limiting this meeting to one day was too short. Also Payne suggested that individuals should be tasked with items to propose at the meeting.
The LO group in Charlottesville has found that LO power distribution as shown at present in the system block diagram has two problems: too much loss in long waveguide runs and Webber's mechanical waveguide switches which may not have good repeatability of phase. Consequently, the final power amplifier for each multiplier chain needs to be as close to the dewar as possible, on the warm side of the cartridge. A few more components within the phase-lock loop will also be put on the cartridge, constituting a warm multiplier assembly. Having some components within the phase-lock loop attached to the cartridge means that the WR22 waveguide or coax runs from the source located elsewhere on the receiver package will be inside the phase-lock loop, which is needed to eliminate any phase changes due to temperature changes of the wg/cable runs. The group is looking at several different designs of the overall configuration and will make a decision in the next few weeks; the recommended system will use all solid-state switches.; The size of the assembly will be about 1 x 2 x 5 inches; it attaches to the warm side of cartridge (sticks out the back). Please send comments to Webber (jwebber@nrao.edu). A document will be forthcoming. Webber confirms sufficient power from components already built up to 275 GHz. A memo on temperature-induced phase slow phase drift will be published shortly. The cold multipliers will be at the 50 K and/or 15K stages, depending on cartridge, with a power level of a few hundred microwatts on the final multiplier stage. The heat dissipated here will have to be insulated from the SIS mixer.
It is now almost certain that the Japanese will join the ALMA Project as a third and equal partner. We will have more information after the meeting in Tokyo.
Brown states there will be a full calibration meeting in the future.
The Receiver PDR will be in Tucson, AZ, 2001-Feb-19--2001-Feb-20.
Next JRDG Teleconference will be Thursday, December 7, 2000 at 1600 UTC.
Widget List to JRDG
Who: John Payne
Update: list has been sent out and a few more issues
need to be settled
Polarization Document
Who: Larry D'Addario
Update: Not yet completed
Dewar Deflections
Who: Brian Ellison
Update: Work is on-going. Need more detail on what
we actually require.
Tolerance Report
Who: Matt Carter
Update: Work is continuing
Analysis of Optical Performance
Who: James Lamb, et al.
Update: Still in progress; deadline set of 2000-Nov-10
Interaction of Optics Aberrations with Aberrations of Chopping secondary
Who: James Lamb
Update: done
Baseline Design for Each Style
Who: Matt Carter, et al.
Update: In progress; due date 2000-Nov-10
IR filters and windows: Define work packages
Who: John Payne and Wolfgang Wild
Update: In progress; work package will be given
to IRAM
Add Tolerances to Deflections
Who: James Lamb
Due Date: ???
Dewar Deflections
Who: Brian Ellison
Due Date: ????
Circulate Work Package
Who: Bernard Lazareff
Due Date: 2000-Oct-27
Draft Agenda for Receiver Production Meeting
Who: Richard Wade, John Payne, & Wolfgang Wild
Due Date: 2000-Nov-03
Extending Receiver Production Meeting to a Two Day Meeting
Who: Richard Wade
Due Date: 2000-Nov-03
Email Widget List to ASAC
Who: John Payne
Due Date: 2000-Nov-03
Analysis of Optical Performance
Who: James Lamb, et al.
Due Date: 2000-Nov-10
Baseline Design for Each Style
Who: Matt Carter, et al.
Due Date: 2000-Nov-10
Discussion on Polarization Document
Who: John Payne
Due Date: 2000-Nov-15
Distribute Current Deflections
Who: Mark Harmen
Due Date: 2000-Nov-30
Minutes recorded and submitted by Carolyn White