Prioritized Spares / Limited Life / Consumables List

Instrument will be off-line while this replacement happens.

Some care required, or extended time required for replacement

Component easily accessible with minimal time required for replacement. Partial or no instrument down-time required for change.

Note indicating an optical realignment or verification is required after the component is replaced.

Vacuum chamber gate valve must be closed, and Vac Cart enclosure opened to replace pump. Vacuum pressure within chamber will be rising during this time (affecting instrumental stability), making this replacement time-sensitive. A WMKO turbo cart could be connected to the chamber during the replacement to help minimize the vacuum pressure change.

Now appears to be ~$17k, see this link. (-JW 2023-08-21)

major impact

• Chamber would start to lose vacuum pressure

• During time required to obtain replacement pump, vacuum pressure would rise significantly and reset the instrumental stability time series.

Vacuum chamber gate valve must be closed, and Vac Cart enclosure opened to replace pump. Vacuum pressure within chamber will be rising during this time (affecting instrumental stability), making this replacement time-sensitive. A WMKO turbo cart could be connected to the chamber during the replacement to help minimize the vacuum pressure change.

Now appears to be ~$17k, see this link. (-JW 2023-08-21)

major impact

• Chamber would start to lose vacuum pressure

• During time required to obtain replacement pump, vacuum pressure would rise significantly and reset the instrumental stability time series.

Requires removing the FIU from the AO Bench to gain access to detector.

major impact

• Would not be able to guide on a star with the accuracy required for radial velocity measurements.

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing rotator(s) from FIU,

• removing prism cell from rotator.

major impact

• ADC correction would be impossible, leading to loss of blue and red flux within science spectra. Radial velocity precision would be impacted.

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing stage from FIU

• ensuring mirror is located properly after new stage is installed.

major impact

If it failed out-of-beam:

• We would not be able to calibrate the main spectrometer and monitor instrument drift.

If it failed in-beam:

• Light from the telescope would be blocked.

Easily accessible in a drawer in the Cal Rack (stairwell side). Marked medium difficulty given care must be taken during cable swap, and the time needed to set replacement Galil up with correct IP address.

Might be able to use on-hand DMC-4040 (TBC)

major impact

• At best this would allow use of only one calibration source.

• However, it would likely take the entire Calibration Unit off-line

• We would not be able to calibrate the main spectrometer and monitor instrument drift.

The rotation stage is accessible on the outside of the Calibration Bench, and mechanically this is a straightforward change. The difficulty lies in re-aligning the fold mirror mounted on the rotation stage, so that is directs the light from all sources onto the various fibers.

major impact

• At best this would allow use of only one calibration source.

• However, it would likely take the entire Calibration Unit off-line

• We would not be able to calibrate the main spectrometer and monitor instrument drift.

Requires warming up CCDs, venting main spectrometer vacuum chamber, and removing the large camera-access flange on the side of the vacuum chamber. The ion pumps can be “re-conditioned” at WMKO and re-used.

500 hours at 1e-4mbar

5,000 hours at 1e-5mbar

50,000 hours at 1e-6mbar

500,000 hours at 1e-7mbar

Each cryostat has two ion pumps.

• If one fails: small impact

• If both fail: major impact

  • CCD thermal control will be lost

Requires extracting the Galil’s enclosure from the Aux Rack, opening the enclosure and then replacing the Galil within. Not difficult but somewhat time consuming given the number of cables connected to the enclosure.

Same model is used for the Ca HK Galil in the K1 AO Room.

major impact

• If this Galil fails we cannot control shutters or exposures with kpfexpose.

Backup computer already installed within KPF Calibration Rack. When switching to the backup computer, the USB cable for the Exposure Meter detector needs to be moved from kpfserver to the backup computer.

However the WMKO-standard OS and files need to be installed.

major impact

• If kpfserver goes down, we lose remote control of the instrument (and all telemetry)

Controllers sit within AO Rack on top shelf. Access to controllers is somewhat constrained as the rack door does not fully open. The spares are a PCB board (only) that needs to be installed within an existing MMC-100 controller enclosure.

Works with either the PR-50 rotary ADC stages (science arm) or the PPX-32 linear ADC stages (HK arm).

If Science ADC fails: major impact

• ADC correction would be impossible, leading to loss of blue and red flux within science spectra. Radial velocity precision would be impacted.

If HK ADC fails: medium impact

• HK Spectrometer throughput would suffer, perhaps to the point that spectra were not useable.

• Main spectrometer would be unaffected.

Controllers sit within AO Rack on top shelf. Access to controllers is somewhat constrained as the rack door does not fully open, but still a relatively straightforward replacement.

major impact

If controller failed while mirror was out-of-beam:

• We would not be able to calibrate the main spectrometer and monitor instrument drift.

If it failed in-beam:

• Light from the telescope would be blocked.

FIU does not need to be removed for this shutter to be replaced. The replacement shutter does need to have it’s in-line 5-pin SwitchCraft connector replaced with a right-angled version.

If it fails closed: major impact

• no telescope light can reach KPF

If it fails open: medium impact

• FIU could be used at night, but is no longer protected from dust during the day, and is no longer light-tight to the rest of the AO system (day or night)

The solenoids and other components are accessible on the LN2 cart in the basement. Marked as medium difficulty given there is some risk involved, as care must be taken to avoid water vapor getting into the lines (leading to ice blocking the lines). If ice blocks the lines then the CCD must be warmed up and the lines purged (with a major disruption to the instrument stability timeline).

• Maple PLC (and HMI and I/O modules

• temperature sensors

• pressure transducers

major impact

• CCD thermal control cannot be maintained without LN2 in the KPF dewars. The CCD will start to warm up.

The pumps are easily accessible on the LN2 cart in the basement. Marked as medium difficulty given the steps involved:

• power down the appropriate Instec controller;

• connect the new pump and power it on;

• turn the Instec controller back on;

• ensure Instec set point is correct and temperature control enabled.

There is also some risk involved, as care must be taken to avoid water vapor getting into the lines (leading to ice blocking the lines). If ice blocks the lines then the CCD must be warmed up and the lines purged (with a major disruption to the instrument stability timeline).

major impact

• CCD thermal control cannot be maintained with the LN2 pump running. The CCD will start to warm up.

The pumps are easily accessible on the LN2 cart in the basement. Marked as medium difficulty given the software steps involved:

• power down the appropriate Instec controller and disconnect cables;

• connect the new controller and power it on;

• ensure Instec set point is correct and temperature control enabled.

major impact

• CCD thermal control cannot be maintained without the Instec system running. The CCD will start to warm up.

This shutter is designed to be easily removable from the scrambler. Marked as medium difficulty given time required to open the enclosure to access the shutter, and care required while working around exposed optics and fibers.

Consumable item.

major impact

• This shutter controls the exposure time of the main spectrometer. Would not be able to take spectra until shutter is replaced.

The various shutters are designed to be easily removable from their mounts. Marked as medium difficulty given time required to open the enclosure to access shutter, and care required while working around exposed optics and fibers.

Consumable item.

If the Calibration shutters fail: major impact

• We would no longer be able to calibrate the main spectrometer or track instrument drift.

If the SoCal, HK Spectrometer, or Flat Field Fiber shutters fail: medium impact

• The main spectrometer would be unaffected.

Brett Smith (WMKO) installed the replacement when the PCF failed. He said it took about an hour, but one needs to be slow and methodical. Covers, module, output fibers are removed one of which, the IR, is in a tight space. PCF module location is set by pins.

Consumable item.

medium impact

• LFC cannot be used until replaced. Calibrations will have to lean more heavily on the etalon and the HCL lamps while LFC down; could compromise tracking of instrument stability

The SuperK is easily accessible within Etalon Rack.

Consumable item.

medium impact

• If etalon not available, calibrations will have to lean more heavily on the LFC and the HCL lamps.

• Using the LFC instead of the etalon is more expensive, as it leads to more frequent PCF fiber replacements in the LFC.

Requires opening the Exposure Meter enclosure. Detector is on mounting that is designed to be removable.

medium impact

• Main spectrometer would remain operational, however, ability to monitor flux within science exposures would be lost. RV quality would suffer because precise exposure midtimes could not be computed.

Agitator Controller

Galil DMC-30012-BOX (ISCNTL)

Controller is accessible on the outside of the agitator. Several cables will need to be swapped to new controller. Marked as medium difficulty given the agitator is located within the crypt (not easily accessible and potential permits required).

medium impact

• Observations could continue however the radial velocity precision will be impacted.

Motor is accessible on the outside of the agitator. A flex coupling is used between the motor and the agitator mechanism, so no careful alignment required. Marked as medium difficulty given the agitator is located within the crypt (not easily accessible and potential permits required).

medium impact

• Observations could continue however the radial velocity precision will be impacted.

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing Ca HK fibers from stage,

• removing stage from FIU.

medium impact

• Throughput of Ca HK spectrometer would diminish, likely to a point were spectra do not have enough flux to be useful.

• Main spectrometer and rest of system would be unaffected.

Requires opening Ca HK Spectrometer (after swinging it to a horizontal state).

medium impact

• Ca HK Spectrometer would not be usable if detector failed.

• Main spectrometer and rest of system would be unaffected.

Requires extracting the Galil’s enclosure from the HK Rack in the AO Room (somewhat difficult given the number of cables in the rack).

Same model is used for the Shutters and Timing Galil in the basement.

medium impact

• Ca HK Spectrometer would not be usable if this Galil failed.

• Main spectrometer and rest of system would be unaffected.

The broadband sources are easily accessible under the Calibration Bench.

Consumable item.

medium impact

• Would lose some calibration ability but could rely on past calibrations until replacement available. (True?)

Mechanically the filter wheels are easy to remove with no careful alignment requirements. Marked as medium difficulty given the care required to avoid damaging the bare optical fibers within the Calibration Unit enclosure.

medium impact

• Would require a change in calibration strategy (and scripts) but could likely carry on until replacement filter wheel arrived.

The lamps are easily accessible on the exterior of the Calibration Unit.

Consumable item.

If one lamp fails: minor impact

• we can rely on the other lamp of the same type until replacement arrives.

If both lamps of the same type fail: medium impact

• we lose ability to wavelength-calibrate daily, and will have to rely on past calibrations. Radial velocity precision might be impacted.

The lamps are easily accessible on the exterior of the Calibration Unit.

Consumable item.

The HCL power supplies are easily accessible within the Calibration Rack.

If one supply fails: minor impact

• we can rely on the other lamp of the same type until replacement arrives.

If two supplies of the same type fail: Minor impact

• we could swap supplies around to have one lamp of each type operational until replacement arrives.

If three supplies fail: medium impact

• we lose ability to wavelength-calibrate daily, and will have to rely on past calibrations. Radial velocity precision might be impacted.

These shutters are designed to be easily removable from the scrambler. Marked as medium difficulty given time required to open the enclosure to access the shutters, and care required while working around exposed optics and fibers.

Consumable item.

medium impact

• If one of these shutters fails in a closed state, that light path (Science or Sky) cannot be used until the shutter is replaced.

Mechanically the stage is easy to remove, and the intensity monitor detector is simply mounted (on a post with no careful alignment requirements). Marked as medium difficulty given the care required to avoid damaging the bare optical fibers within the Calibration Unit enclosure.

minor impact

• If stage failed out-of-beam, it could stay there until replaced.

• If stage failed in-beam, it could be removed from system until replacement is available.

Requires warming up CCDs, venting main spectrometer vacuum chamber, and opening chamber door(s) to gain access to the motors under the optical bench. Depending on the motor’s location, the Vac Cart, Aux Rack and LN2 Autofill system might need to be disconnected and moved out of the way so the chamber door can open.

Used very infrequently (mainly for initial alignment of bench or realigning after a significant earthquake). Powered off when not in use.

small impact

• Loss of one motor could likely be compensated for through adjustment of the other four.

• It is very unlikely we would vent the chamber only to replace one of these motors.

Easy

192.168.23.240   iplanet-igs801m-kpf-socal-switch

Industrial grade switch for temperature extremes on roof.

None

small impact

Loss of SoCal