2004 December 14 Telecon Minutes


Scribe: AlWootten

Attendees

  1. DarrelEmerson
  2. Brian Glendenning
  3. Rich Grub
  4. MarkHoldaway
  5. Robert Laing
  6. RobertLucas
  7. JeffMangum
  8. Rick Murowinski
  9. Debra Shepherd
  10. Dave Silva
  11. Dick Sramek
  12. AlWootten


Action Items

Assigned to Due date Description State Notify  
Main.Silva 2005-01-01 A couple of pages on issues before January 2005. (go to action) open edit
Main/Murowinski.Laing 2005-01-01 Put today's discussion into revised plan for tomorrow. (go to action) open edit
AlWootten 2005-01-01 Propose an Agenda like form for Jan discussion. (go to action) closed AlWootten edit
Main.Murowinsky 2004-12-15 Post revised CSV Project plan on this wiki. (go to action) open edit
---

Minutes

  • RM: Most interesting to walk through the list of notes.
  • RL: We need to understand what is what, and what we'll do in January at the AOC.
  • RM: I put definitions of items in my presentation in September.
  • AW: This may be found at http://tinyurl.com/4vldp
  • MH: A simple but broad principle is that if we observe an external source it is astronomical
  • RM: I do not agree with that. My definition of commissioning was given in my September talk to the IPTs.
  • AW: The URL for this is http://tinyurl.com/4vldp but I could not find the word 'commission' in the talk.]
  • DS: A basic question? Is the meeting 14-15 Jan?
  • All: Yes.
  • RM: Splinter meeting to speak of definitions and responsibility--let us limit it to a certain period of time. Two hours on the evening of the 13th. 8-10pm Thursday evening? Rick, Al, Robert, Dave, in this group. We'll work around flight times if needed.


Details

  • Dick will have a draft which includes SE&I at the ATF which supports commissioning if indeed you guys are doing that. PSI plan will have clear blocks of tasks which science group needs to do.
  • DS: Is computing group also identified?
  • RS: Yes but not as explicitly as science. This will be sent out in a few days I hope.
  • RL: Supply minutes of meeting in Garching to RS. DS will circulate by the end of today.
  • AW: I see ATF as the pathway to success in Chile. Is there dissension?
  • RM: Problem will be that budget will not cover everything. BG: If we don't keep the ATF going it will be a disaster in Chile; enthusiasm will wane as the pain increases. The ATF cannot be a descope option.
  • RM: I agree this is absolutely necessary; it will cost more to fix the problems later if we do not get it right now. I begin to wonder if there are commissioning like activities which we can let slide into ops and will be pressured to go there.
  • RL: If the perspective is that there is a pot of money out of which construction might come.
  • DS: Let me be devil's advocate. The reality is that the ATF has had problems keeping the antennas running. That is a distraction. In the end, these are not the antennas and interfaces we will have to deal with in Chile. It isn't clear to me that this makes critical difference.
  • RSramek: The antenna is just a bucket. Much of the work will be computer interfaces and system level testing of all of the other items. My understanding of the plan from FE is that they will send two preproduction units to the ATF. We will have a complete system; we can even include the production BE. By the time it ends we should test on items very similar to what goes to Chile. A lot of debugging will go on in the lab.
  • JM: Great to do tests in the lab but for the AEG the environment is very different from what is in the lab.
  • BG: Comment to Dave's point--the number of modules with ICD changes between the ATF and Chile is not that many--about 20 ICDs, and about 15-16 are going to be the same. We need the equipment, of course, not the ICDs.
  • JM: Debugging these is critical. Most were not followed by hardware or software at the ATF in the AEG tests. Much is due to time pressures.
  • RM: This will not happen. This didn't happen at the ATF.
  • DS: We are all saying the same thing.

In Jan we need to come up with manpower estimates and where the resources will come from. This should be a focus of the talks.

  • RM: This is explicitly in the draft SoWs.
  • RL: Move into Chile. General points--numbers for lengths of time to do things for the antennas compared with AEG experience diverged. RM saw summary.
  • RL: Worried that the discrepancies were in the single antenna area.
  • JM: Notes that the antenna based plan take longer on A1 than A2 through N. Try to build in some time for debugging. It always took weeks to do this for M&C when some new equipment came in. I built this into individual tasks. Rick had working margins in his plans.
  • RL: The size of the discrepancy seems large; is this a real problem? Optical tracking and pointing take 20 days in JM and 5 in RM plans.
I assume we will have pointing routines from the ATF; OPT is known, tested, functioning. Do we really need 20 days? Providing we have satisfactory tests at the ATF do you still think your numbers are realistic? JM They are conservative. I did assume that when we begin to use OPT we will find problems--data out, things that might be stabilized earlier on.
  • RM: I assume that we will have solved these problems. At OSF RM had 10 days, JM had 20 days. JM included factors such as moving an antenna the first time, determining pad tilt, etc. RM there will be a new OPT system with data transmission changes, plate scale problems. BG at high site analog video transmission not such a good idea; digitize at the camera.
  • RM: Puts a lean estimate, then gives working margin of 25-50% depending on difficulty.

What does PMCS need from us and how do we get it to them.

  • RM: Can go through the plan in detail and supply another version. Agreement on having one interface to PMCS.
  • RM: In my view one still needs another plan that covers science verification and software and all. The data mangement items are in this and need to be put into the PMCS system also. DS offered to put together overheads on what should go into data management. Some can be done now but much will have to wait until 12-18 months into operations. RM thinks that science verification is running data through the system. We agree that if this will draw on construction phase money this should go into PMCS, This is an Ops phase task. This needs to be in someone's product tree. We need to consider how we make this work as a science operations system.
  • RL: Willing to work with him to start this before Jan. Perhaps a strawman before Jan meeting.


Interferometry at the OSF

  • MH: Looked at astronomical sources--SG said he thought they would be fine.
  • RL: We have done this at PdBI. We compared masers and quasars. The latter is best at 90 GHz--15 Jy for 3C273. Simulated holography in a new program. Noise goes up as one increases the number of points. Resolution of 0.8 m gives good sensitivity 5 microns to edge of dish. This can verify the elevation dependence of the backup but not for setting panels.
  • RM: We do that with the transmitter. I agree with JM.
  • JM: Everyone understands why we might need the interferometric holography at the OSF. This will check bus stiffness. In principle this is an antenna IPT task. They need to be brought in. A technique of out of focus beam maps can also be employed. Need highest frequency, use single dish. We need to decide which we will want to do. The work for interferometry may require more work to equip the OSF for it.
  • RM: It will help qualify the equipment in a controlled environment. We will probably need to do out of focus beam maps for the first antenna. Holography will be useful at the high site.
  • MH: Your calculations are based on a second antenna on axis. More antennas would all scan but for one. One could use more reference antennas. The improvment at the AOS is sensitivity.
  • RS: Probably use a few antennas for reference.
  • RL: Usually we have half scanning, half as reference. But you need very good phase conditions to do this, and short baselines.
  • DS: At the VLA we use a third as ref, only in the compact configuration
for 8 hrs with 3C273. MH: One could do something like FS to take out the atmosphere--do this after every few rasters. RL It is clear that the faster you go to the reference the more you win--every 10-20 seconds would win.
  • RL: We decided the single bselin interferometer at the OSF is a GOOD idea but the details there and at the AOS need to be decided.
  • RM: Had the opposite conversation with JC--tasks on antenna one belong to SEI or to antenna.
  • RS: This isn't a natural fit for the Antenna IPT to develop expertise on holography.
  • JM: It should be a Sci IPT task that the Antenna IPT tracks.
  • Credland (In Abstentia): As soon as accepted from contractor it is ours they (ant ipt) don't want any more to do with it. Look at resources, etc.

The mpp file should be on the wiki. The next version should be posted tomorrow.

-- JeffMangum - 15 Dec 2004
Topic revision: r2 - 2009-04-15, AlWootten
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