1. DECam in 2014 - Overview Alistair Walker Version 3 December 1 2013 Ver 4 Updates Jan 21 2014 1

2. Preamble This presentation covers FY14 (October 1 2013 to September 30 2014) DECam is a system – it is much more integrated with the telescope and facility than earlier instruments. Which means that everything has to work! 100% of (observing) telescope time in 2013A and 2013B. Probably >90% of (observing) telescope time in 2014A and 2014B 2

3. DECam Issues Today Why is CCD S30 not working?(Marco Bonati, Peter Moore, with Juan Estrada) FAULT APPEARS INTERNAL – STILL UNDER DISCUSSION, INCLUDING STEVE HOLLAND Is the non-functioning of the hexapod actuator #6 incremental encoder a wiring/connector problem? (Telops, ADS) YES - FIXED Check the SISPI computers and replace dying disks (CISS) REGULAR “MAINTENANCE” Pumping one cryo head, poor vacuum in the LN2 line segments (1S, 1R) where they pass into the PF cage (Telops) NO RESOLUTION YET, BIG ISSUE Understand the in-DECam humidity variations (Telops) MAY ENGINEERING Shutter hardware errors (see later), software errors (Klaus, Marco) ON- GOING, RUNNING TESTS FOR THE BONN SHUTTER FOLKS F/8 Handler problems (included for completeness but not mentioned again in this document) ON-GOING 3

4. DECam Issues Today II CCDs low light level non-linearity (Marco Bonati, Fermilab) TESTS SHOW THAT BIAS ADJUSTMENTS DO NOT FIX THIS, WILL (CONTINUE TO) FIX IN THE REDUCTION PIPELINES LN2 system CRIo reconstruction (Marco Bonati, Rodrigo Alvarez) – install May 2014 START IN MARCH (TBC) Improve robustness of wires and fibers associated with the Monsoon crrates (Telops, ETS, to be defined). NO PROGRESS YET 4

5. Regular Maintenance – the Biggies LN2 pump replacement. – The time for the next replacement is May 2014. – There have been some pump and controller improvements, and the pump is now on a UPS. – There are plans for further pump improvements including changing the operation (pressure, flow) parameters but it is not clear yet whether we will ever be in the situation of 12-month changes. MORE DISCUSSION AS SOON AS FERMILAB TESTS ARE COMPLETE Resources: Freddy Muñoz + TELOPS one week 5

6. Regular Maintenance – the Biggies Filter and Shutter mechanisms – We need to grease the slides etc – The shutter has already given signs of “sticking” – It’s a big deal to remove them from the instrument – We also have a new filter coming to install – Schedule for March 2014 MARCH 11-16 RESOURCES: Patricio Schurter a/o Freddy Muñoz + Telops. For filter handling: Roberto Tighe and ? Time: one week 6

7. More Regular Maintenance Data Acquisition System Marco Bonati is a critical resource NESLAB system, Cage cooling system (Telops, Freddy Muñoz) Facility Utilities (Telops) – Dry air – LN2 – Vacuum – Gycol – Power Mountain Power (DECam has power monitoring installed, Telops) BLANCO JIRA SYSTEM NEEDED (ACTR 472 Manager T. Abbott) YES, AS OF JANUARY 10 Computer disks (CISS) Mountain network (CISS) 7

8. DECam Environment Improvements Cage Covers (in progress). (ACTR 442, Freddy Muñoz + Instrument Shop) – Then the cage cooling system will work IN PROGRESS, ALMOST READY FOR FINAL INSTALLATION Blanco hydraulic bearing oil cooler (ACTR ?, Telops, Edison Bustos) – Tim proved (again) that the oil is really hot DONE! Dome air conditioning - install, then optimize (ACTR new, Brooke) – The ETS resources are needed for the console room roof modifications IN PROGRESS New ECS algorithm – better control of the primary mirror temperature (ACTR 464, Alistair, Edison Bustos) A TEMPORARY AD-HOC ALGORITHM IS BETTER THAN THE OLD ONE Lag the high pressure helium lines from the compressor to the LN2 tank (Telops) NOT YET DONE New, reliable DIMM (New Project, Andrei, Edison Bustos) PARTS ON ORDER 8

9. Other Telescope Improvements that will benefit DECam Blanco Primary Mirror Support System - New high-resolution hardware allowing use of a LUT for astigmatism (at least) as a function of sky position (ACTR 470, Tim, Michael Warner) PROTOTYPE INSTALLED, AS OF Jan 13, UNDER TEST New dome encoders – a SIGNIFICANT number of DECam images are occulted by the dome ( Manuel Martinez, Andres Montane, ready for by the end of November) INSTALLED, WORKS, TUNING OF CONTROL UNDERWAY Wind blind encoding? (ACTR ?) NO PROGRESS 9

10. Still More Telescope Improvements Understand and improve telescope pointing (ACTR 443, Tim, Rolando Cantarutti, Omar Estay) Better integrate TCS and the DECam hexapod (associated with the above) UNDER DISCUSSION Understand the Active Optics System and Image Quality Including the BCams (DES team, Roberto, Alistair…) ON- GOING More telemetry: cage temperatures, anemometer, accelerometers (Kevin Reil-SLAC, Michael, Telops) ACCELEROMETER INSTALLED Jan 14, ANEMOMETER ARRIVED 10