Prioritized Spares / Limited Life / Consumables List

VERY DIFFICULT

Instrument will be off-line while this replacement happens.

MEDIUM DIFFICULTY

Some care required, or extended time required for replacement

EASY

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

OPTICAL REALIGNMENT

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

Vac Cart

Turbo Pump

Leybold TurboVac 450iX

1x

$7,700

VERY DIFFICULT

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)

None

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.

Vac Cart

Roots Pump

Leybold EcoDry 65 Plus

1x

$9,600

VERY DIFFICULT

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)

None

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.

FIU

Guide Detector

First Light
Advanced Imagery
C-RED 2

1x

$39k /
6 weeks

VERY DIFFICULT

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

None

MAJOR IMPACT

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

FIU

ADC Prism Rotators

Micronix PR-50-C0017

2x

$5,500 ea / 10-12 weeks

VERY DIFFICULTOPTICAL REALIGNMENT

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing rotator(s) from FIU,

• removing prism cell from rotator.

None

MAJOR IMPACT

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

FIU

Calibration Fold Mirror Stage

Micronix PPS-20-C0035

1x

$4,400 ea / 10-12 weeks

VERY DIFFICULT
OPTICAL REALIGNMENT

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing stage from FIU

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

None

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.

Cal Unit

Galil Motor Controller (Octagon and Intensity Monitor Stage)

DMC-4020(MO)-C022-I000-D4140

1x

MEDIUM DIFFICULTY

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.

Cal Unit

Octagon Stepper Motor

Thorlabs NR360S

1x

$2,700

VERY DIFFICULT
OPTICAL REALIGNMENT

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.

None

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.

Aux Rack

Cryostat Ion Pumps

Gamma 3SDI1V5KNN (3S TiTan)

4x

$770 /
6-7 weeks

VERY DIFFICULT

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

None

Each cryostat has two ion pumps.

• If one fails: SMALL IMPACT

• If both fail: MAJOR IMPACT

  • CCD thermal control will be lost

Aux Rack

Shutters and Timing Galil

Galil RIO-47142-16BIT

1x

$465

MEDIUM DIFFICULTY

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.

1 spare

MAJOR IMPACT

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

Computer

kpfserver

ASL Lancelot
2884-SRT

1

$10k /
1 week (in 2021)

EASY

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.

1 spare

MAJOR IMPACT

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

FIU

Science ADC or HK ADC Controller

Micronix
MMC-100-PCB Piezo Motor Controller Board

3

MEDIUM DIFFICULTY

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).

2 spares

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.

FIU

Calibration Mirror Linear Stage Controller

Micronix MMC-200-01110 stepper motor controller

1

EASY

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.

1 spare

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

Front Hatch

Uniblitz NS45B1T1 Shutter

1

$960 /
4-5 weeks

MEDIUM DIFFICULTY

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.

1 spare

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)

LN2 Cart

Autofill System

2x solenoids

MEDIUM DIFFICULTY

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).

3x Solenoids

Also shared spares available for:

• 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.

Aux Rack

LN2 Pumps

Instec LN2-SYS

2x

MEDIUM DIFFICULTY

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).

1 brand-new spare;
1 used spare

MAJOR IMPACT

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

Aux Rack

Instec Controller

Instec mK2000B

2

$5000 / 4-6 weeks

MEDIUM DIFFICULTY

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.

1 spare

MAJOR IMPACT

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

Fiber System

Scrambler Timed Shutter

Uniblitz NS65B

1x

$1,280 /
4-5 weeks

MEDIUM DIFFICULTY

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.

1 spare

MAJOR IMPACT

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

Cal Unit

Shutters

Uniblitz DSS25B

6x

(2x Cal Bench,
1x Flat Field, 2x SoCal,
1x HK)

$540 ea /
4-5 weeks

MEDIUM DIFFICULTY

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.

3 spares

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.

LFC

Photonic Crystal Fiber (PCF)

Menlo Systems

1

MEDIUM DIFFICULTY

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.

None

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

Cal Unit 

Etalon Super Continuum

NKT SuperK EVO

1x

$33.5k for new device, $8.5k to refurbish existing device. Lead time: 4-6 weeks.

EASY

The SuperK is easily accessible within Etalon Rack.

Consumable item.

Ordered (Aug 2023)

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.

Exposure Meter

Exposure Meter Detector

SBIG Aluma 47-10

1x

$15k /
6-8 weeks

MEDIUM DIFFICULTY

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

None

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.

Fiber System

Agitator Controller

Galil DMC-30012-BOX (ISCNTL)

1x

MEDIUM DIFFICULTY

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).

None

MEDIUM IMPACT

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

Fiber System

Agitator Motor

Galil BLM-N23-50-1000-B

1x

$500 /
1-2 weeks
(in 2018)

MEDIUM DIFFICULTY

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).

None

MEDIUM IMPACT

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

FIU

H&K Fiber Stage

Micronix PPX-32CR-C0002

1x

$4,500 ea / 10-12 weeks

VERY DIFFICULTOPTICAL REALIGNMENT

Requires:

• removing FIU from AO Bench,

• opening FIU,

• removing Ca HK fibers from stage,

• removing stage from FIU.

None

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.

Ca HK

Ca HK Detector

Andor Newton 920 (with UV-optimized CCD)

1x

$37k / 12 weeks

MEDIUM DIFFICULTY

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

None

MEDIUM IMPACT

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

• Main spectrometer and rest of system would be unaffected.

Ca HK

Ca HK Galil Controller

Galil RIO-47142-16BIT

1x

$465

MEDIUM DIFFICULTY

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.

1 spare

MEDIUM IMPACT

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

• Main spectrometer and rest of system would be unaffected.

Cal Unit

Broadband Source 

Thorlabs SLS201L

2x

(1x Octagon, 1x Flat Field)

$1,200
No lead (June 2023)

EASY

The broadband sources are easily accessible under the Calibration Bench.

Consumable item.

None

MEDIUM IMPACT

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

Cal Unit

Filter Wheel

Thorlabs FW102C

3x

(1x Octagon, 1x Flat Field)

$1,300
No lead (June 2023)

MEDIUM DIFFICULTY

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.

None

MEDIUM IMPACT

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

Cal Unit

ThAr Lamp

Green Scientific G858A

2x

(1x Daily,
1x 'Gold')

$405

EASY

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

Consumable item.

No current spares

6 are on order

* updated *

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.

Cal Unit

UNe Lamp

Photron P863

2x

(1x Daily,
1x 'Gold')

$825

EASY

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

Consumable item.

4 spares

Cal Unit

HCL Power Supply

Photron P209 Hollow Cathode Lamp Power Supply

and

Green Scientific G200

4x

(1x Th-Ar Daily,
1x Th-Ar Gold,

1x U-Ne Daily, 1x Un-Ne Gold)

Green Scientific Supply:

$730

EASY

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

1x Green Scientific Power Supply

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.

Fiber System

Scrambler Source Select Shutter

Uniblitz RS20B

2x

$550 each (minimum quantity was 10 last time we ordered). Lead time: 5-6 weeks

MEDIUM DIFFICULTY

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.

10 spares

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.

Cal Unit

Intensity Monitor Stage

Newmark MSL-50-21

1x

$1,100

MEDIUM DIFFICULTY

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.

None

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.

Vac Cart

Isolator Stepper Motors

Lin Engineering 4118M-06S-22RO

5x

VERY DIFFICULT

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.

None

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.

SoCal

Network Switch

Planet IGS801M

1x

EASY

192.168.23.240   iplanet-igs801m-kpf-socal-switch

Industrial grade switch for temperature extremes on roof.

None

SMALL IMPACT

Loss of SoCal

Cal Unit

Compensator Motor

Newport TRA12PPD

4x
(2x BS,
2x Fold)

Need TBD