GISMO run #7; 2nd pool run (November 2012)

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Staffing

• GSFC: S. Maher, E. Sharp (preparation days & 1st week); J. Staguhn, T. Sun (1st & 2nd weeks); A. Kovacs (1st week); D.Benford (2nd week)

• IRAM: M. Gonzalez, C. Kramer (1st week); S. Leclercq, N. Billot, G. Bruni (2nd week)
• External pool observers: I. Perez-Fournon, M. Hogan (1st week); R. Launhardt, R. Eufrasio (2nd week)

Schedule: 05.04. - 21.04.2012

• IRAM 30m schedule page: http://www.iram.fr/IRAMFR/PV/sche/sche.html
  

• GISMO log: https://mrt-lx1.iram.es/Devices/GISMO/ (internal)

Summarized schedule of the run:

GISMO final version

• Same 8x16 pixels as runs 2 to 6, working at 2mm (the –3dB window is 140-162 GHz), with an individual pixel size = 0.9 Fλ.

• Same special features from previous runs: Automated observing procedures usable via a dedicated GUI (see observer's manual), CRUSH reduction package, cold baffle, final position in the receiver cabin with corresponding warm optics (M5, M6)

• New cold pupil.

Daily reports

Friday 26/10

We have the electronics and computers setup and GISMO is on the pump. IRAM left the electronics in the cabin which gave us a head start. We also decided to put the cabling above the floor (with a good metal cover) to reduce the chances of breaking thermometry cables while fishing cables and also to make setup/teardown easier. We also cleaned up the IRIG isolation cabling and put the isolator box in the rack. The server was a little stubborn to boot but eventually gave in. The server, client, crate, IRIG, are up and running. We also made some fresh clones of the server disk and tested the backup server (booted and started GISMO software).

Saturday 27/10

Continuing without problem. Weather getting a little better. Continuing cooldown. Added nitrogen. Prepared GISMO Nexus for new run. Removed ground breaker from electronics circuit. Completed disk backups and setting up client. Elmer working on optical models and helium in-gassing prevention design.

Monday 29/10

Completed cooldown (took lots of IV curves during extension cooldown). Telecon with IRAM. Added more thermometry (extension) to Nexus/alarm system. Took some initial observations during technical time. We had a problem with IDL license (the error was the license file does not exist - as opposed to last spring where there were too many users). I copied the license file from gra-lx1 and that worked. Also, CRUSH now(?) wants headers in initial log file, so I obliged. Finally, I ran into gismo directory permission problems and emailed Walter. After clearing things up I manually sent the data through the backend - see [[GISMO Nexus|https://mrt-lx1.iram.es/Devices/GISMO/])

Thursday 01/11

Yesterday we made a few tests during the bad weather with the window blanked off. The aluminum plate was bolted to the bottom of the cryostat and we configured GISMO with different types of grounding schemes to find the lowest possible noise. After collecting many data sets, we discovered that the best configuration is with all of the electronics connected to the electrical ground in the cabin and the cryostat vacuum shell connected to isolated ground. The isolated ground is a special cable feed into the receiver cabin and has the closest possible contact to the earth ground for the telescope. In this configuration, we were able to consistently get an NEFD of 9 mJy*s^0.5

Since the bad weather is continuing today, we will try to make further grounding tests.