1. Alistair Walker Version 3 December 1 2013
DECam in Overview
Alistair Walker
Version 3 December

2. Preamble
This presentation covers FY14 (October to September )
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

3. DECam Issues Today
Why is CCD S30 not working?(Marco Bonati, Peter Moore, with Juan Estrada)
Is the non-functioning of the hexapod actuator #6 incremental encoder a wiring/connector problem? (Telops, ADS)
Check the SISPI computers and replace dying disks (CISS)
Pumping one cryo head, poor vacuum in the LN2 line segments (1S, 1R) where they pass into the PF cage (Telops)
Understand the in-DECam humidity variations (Telops)
Shutter hardware errors (see later), software errors (Klaus, Marco)
F/8 Handler problems (included for completeness but not mentioned again in this document)

4. DECam Issues Today II
CCDs low light level non-linearity (Marco Bonati, Fermilab)
LN2 system CRIo reconstruction (Marco Bonati, Rodrigo Alvarez) – install May 2014
Improve robustness of wires and fibers associated with the Monsoon crrates (Telops, ETS, to be defined).

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.
Resources: Freddy Muñoz + TELOPS one week
SISPI – and friends – very mature, see 6997

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
RESOURCES: Patricio Schurter a/o Freddy Muñoz + Telops. For filter handling: Roberto Tighe and ? Time: one week
SISPI – and friends – very mature, see 6997

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)
Computer disks (CISS)
Mountain network (CISS)
SISPI – and friends – very mature, see 6997

8. DECam Environment Improvements
Cage Covers (in progress). (ACTR 442, Freddy Muñoz + Instrument Shop)
Then the cage cooling system will work
Blanco hydraulic bearing oil cooler (ACTR ?, Telops, Edison Bustos)
Tim proved (again) that the oil is really hot
Dome air conditioning - install, then optimize (ACTR new, Brooke)
The ETS resources are needed for the console room roof modifications
New ECS algorithm – better control of the primary mirror temperature (ACTR 464, Alistair, Edison Bustos)
Lag the high pressure helium lines from the compressor to the LN2 tank (Telops)
New, reliable DIMM (New Project, Andrei, Edison Bustos)

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)
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)
Wind blind encoding? (ACTR ?)

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)
Understand the Active Optics System and Image Quality Including the BCams (DES team, Roberto, Alistair…)
More telemetry: cage temperatures, amenometer, accelerometers (Kevin Reil-SLAC, Michael, Telops)