Content Comparison

Ca H&K Spectrometer

• Throughput requirement met by calculation

  • measurement deferred to on-sky

• Met all other requirements

• Trouble with trigger signal to start exposures has meant it has not been in regular use

• On-sky throughput measurement still TBD

  • requires testing of HK ADC within FIU

• Continued troubleshooting of trigger signal

• On-sky throughput tests

  • part of FIU HK-arm ADC alignment tests

Calibration Unit

• Could not fully test the Calibration Unit at SSL since compensator motors had very long lead and were not in-hand.

• Calibration Unit was set into a state that allowed use but was not the final configuration.

• New plan is to not use motors but purchase filters with higher tolerances. 

• This will make for a simpler system going forward (and one easier to maintain as 4 less motors involved, no look-up table to maintain)

• There have been issues with Photron lamps and power supplies:

  • Photron no longer makes Th-Ar lamps

  • One (of the four) KPF Photron power supplies

  • solved by moving to failed (for no apparent reason)

• Going forward KPF will use Green Scientific lamps and

  supplies

• However there are still 3x Photron power supplies in the system

Filter purchase waiting on funding; will install filters during servicing mission.power supplies

• Initial Green Scientific lamp failed quickly, but the second one has lasted longer

Servicing mission items:

• install filters with higher wedge-angle tolerances

LFC

• LFC availability was sparse.  A combination of sub-optimal thermal variations in the high-bay (10’s of degrees F thermal variation over 12 hours) and incomplete software automation precluded extended operation of the LFC at SSL.

• Comb has been operational but there has been significant down-time due to Menlo hardware and software issues.

• Occasional help with installing hardware (i.e. PCF fiber modules)

• Maintaining comb via software controlMonitoring LFC control software to maintain performance has proven to be time-intensive

Etalon

• Was not available for tests at SSL.

• Current etalon has been used regularly

• However etalon light source (SuperK) is failing our moving out of alignment

• Troubleshoot SuperK-to-etalon alignment (underway)

• Secure another SuperK to have a spare on hand

Cryostats/CCDs

• Fully passed majority of requirements

  • Some requirements were just missed but deemed OK.

• Fringing was significantly worse than requirement, plan was to correct in software

• Some fixed-noise patterns on CCDs caused by insufficient grounding

• Charge Transfer Efficiency (CTE) issue on one quadrant of Green CCD

• Fringing patttern pattern still present

• Grounding straps to be attached between Archon and vacuum chamber (underway)

• Change readout mode on Green CCD to avoid CTE issue

• Investigate ways to minimize fringing impact within DRP

Environmental Control System

• Vacuum Chamber met requirements

• Thermal enclosure not designed/built

• Thermal enclosure to be installed later this year

Servicing mission items:

• bring linear potentiometers online (provide bench position feedback)

• bring gate valve position feedback online

Exposure Meter

• Throughput requirement met by calculation

  • measurement deferred to on-sky

• Met all other requirements

• In regular use

• Test using the Exposure Meter in an automated way to terminate an exposure at the correct signal-to-noise ratio.

• Determine on-sky throughput (and compare to main spectrometer)

Fiber Injection Unit

• Optical performance and alignment requirements met

• Centering stars on fibers has proven proved to be challenging

• FVCs have been more challenging to use than expected.

• Prisms within Science arm ADC appear to not be set correctly

• Will update this section once Josh returns from vacation

Optical Fibers

• All requirements met

• Backup Simulateous Simultaneous Cal fiber was damaged during installation. There are no current plans to build a replacement.

Agitator

• Was not tested at SSL

• In regular use

• Quantify agitator performance via “agitator on” vs. “agitator off” test.

Instrument Control Software

• Nearly all dispatchers written (only exposure meter, LFC, and etalon TBC)

• Minimal alarms in place

• All dispatchers now operational

• “testall” script in regular use

• Alarm system fully functional with important alarms in place

• Archon has occasional trigger-signal issues

• Backup computer is on summit but not operational (needs OS installed)

• Potential need for help troubleshooting Archon trigger signal issue

• Installation of backup computer

• Add more alarms for various telemetry items

Observing GUI

• Sketches and plans but no code before PSR

• In regular use

• Two areas still need some effort:

  • tip/tilt control and status GUI

  • automated exposure meter control of exposures

Spectrometer

• Throughput requirement met by calculation

  • measurement deferred to on-sky

• Met all other requirements

• Fiber block in reformatter is slightly out of alignment

• Green channel focus is soft in one corner of CCD

• Flat field fiber system needs slight realignment

• Ion pumps on cryostats are generating low levels of stray light

• Throughput matches model except at bluest end of full bandpass

  • could be a symptom of incorrect ADC correction

• Servicing mission items:

  • fiber block re-alignment

  • Green channel focus adjustment

  • flat field fiber re-alignment

  • add baffles to ion pumps

SoCal

• Not included within PSR scope

• Installed at Keck and in regular use

have asked Ryan to fill in

LN2 Autofill System

• Original LN2 cart and LN2 transfer plumbing was complete

• Initial tests showed major heat losses within transfer plumbing, which caused GN2 back-pressure issues and prevented dewar fills

• System was completely re-designed to correct these issues

• Autofill system now in regular use, and KPF dewars are filled from supply dewars located in K2 machinery room

have asked Grant for a blurb