This document describes the observations and tests that will be made during the commissioning of the Gemini Near-infrared Integral Field Spectrograph in order to verify its operation and characterize its performance on the Gemini North telescope. The results of these observations and tests will be used to justify acceptance of the instrument under the terms of the construction contract and to finalize the Users Manual and the observation preparation tools. This document lists all commissioning activities, defines the goals to be met, attempts to schedule these activities within the commissioning period, and identifies all personnel and infrastructure resources that will be needed at Gemini North during the commissioning period.

2 Applicable Documents

Document ID	Source	Title
SPE-I_G0074	IGPO	Programmatic Requirements For Gemini Instrumentation Development
SDN0003.01	RSAA	NIFS Operational Concept Definition Document

3 Introduction

The Gemini Near-infrared Integral Field Spectrograph (NIFS) will be used with the ALTAIR adaptive optics (AO) system on the Gemini North telescope. The NIFS commissioning phase will consist of 1) instrument commissioning, 2) science commissioning, and 3) shared risk observing (SPE-I-G0074). This leads to full use of the instrument by the Gemini community. This Verification and Commissioning Plan describes the instrument commissioning phase. The intent of instrument commissioning is to demonstrate that the scientific performance requirements, calibration, key science cases, and key operational modes of the instrument can be accomplished. The observations and tests required to do this, a schedule for performing these tasks, and the manpower and infrastructure resources required are described in this document. Acceptance tests performed prior to the instrument arriving at the Gemini North telescope are not considered in this document.

The NIFS instrument commissioning will be divided into four Verification and Commissioning phases:

Integration and Installation (VC1); This phase will be used by the commissioning team to perform the unpacking, checking for transport damage, re-assembly of the instrument, installation on the telescope, and system health checks.
System Evaluation (VC2); The full commissioning team will be in attendance at the telescope during this phase. The following actions will be performed during the System Evaluation phase:

Test proper function in the telescope environment.
Measure basic performance parameters with emphasis on those specified in the construction contract.
Verify observing scenarios specified in the Operational Concept Definition Document (OCDD; SDN0003.01).

Performance Assessment (VC3); The commissioning team will return to their home institutions for this phase. The Performance Assessment phase will be used to evaluate data obtained during the System Evaluation phase. The commissioning team will:

Correct and/or prepare the implementation of corrective actions for hardware and software problems which were detected during the System Evaluation phase.
Compare the instrument performance to the predicted and designed values, identify necessary modifications, and prepare for their implementation.

System Optimization (VC4); The full commissioning team will be in attendance at the telescope during this phase. The following actions will be performed during the System Optimization phase:

Solve any problems identified in earlier phases.
Complete characterization of instrument properties.
Obtain initial instrument calibration data.
Train the Instrument Scientist and Gemini maintenance staff.
Perform final acceptance tests.

This double-pass approach has the advantage that it allows each operation to be tested twice, if necessary.

NIFS will interact with the telescope system in maintaining accurate pointing and focus using the On Instrument Wavefront Sensor (OIWFS), in performing accurate pointing offsets, in deploying the Instrument Support Structure (ISS) science fold mirror, and in controlling GCAL. NIFS will interact with ALTAIR in deploying the AO fold mirror and in controlling guide star acquisition and AO correction. NIFS will also interact with GPOL in performing spectropolarimetry measurements. Consequently, the NIFS Verification and Commissioning Plan addresses four major aspects; NIFS system verification, telescope system verification, ALTAIR system verification, and GPOL system verification. The actions needed to test each of these aspects are detailed below.

The NIFS Instrument Scientist and maintenance team will be trained during the NIFS commissioning period. This will be facilitated if the NIFS Instrument Scientist and a representative of the NIFS maintenance team are members of the NIFS commissioning team.

4 NIFS System Verification

4.1 Assembly

Item: NIFS Assembly

Phase: VC1

Procedure: NIFS shipping crates are unpacked, the instrument is assembled in the instrument preparation laboratory, standalone computer control is established, basic health checks are performed.

Duration: 48 hours.

Personnel: Conroy, Dawson, Downing, Hart, Young.

Prerequisites: NIFS arrived at Gemini North. Space in instrumentation preparation laboratory. Instrument air pallet. Lifting crane.

Success Criteria: Instrument fully assembled with no transport damage.

Comment: Standalone computer control is needed to regulate cool down (4.2).

4.2 Cool Down

Item: First NIFS Cool Down

Phase: VC1

Procedure: Cryostat is attached to a vacuum pump. Cryocoolers are attached to helium lines. Cryostat is pumped for 24 hr after which the cryocoolers are switched on. The cryostat cool down is controlled by the standalone computer control system. Cool down should take five days to reach stable operating temperature. Cryostat vacuum pressure and internal temperatures are monitored during cool down.

Duration: 150 hours.

Personnel: Conroy.

Prerequisites: High capacity vacuum pump (as for NIRI). Access to compressed helium lines.

Success Criteria: Instrument reaches stable operating temperature and maintains vacuum.

Comment: It is likely that the cryostat will already be under vacuum when it arrives on Mauna Kea and may be partially cold.

4.3 Software Installation

Item: Install NIFS Software in Telescope Environment

Phase: VC1

Procedure: NIFS software is installed in the telescope software environment. Inter-system communications are established and compatibility is tested to the greatest extent possible. Data and Quick Look Display interfaces to the Data Handling System are tested.

Duration: 48 hours.

Personnel: Jarnyk, Young.

Prerequisites: Access to telescope systems. Assistance from Gemini Observatory software staff. Access to telescope software environment.

Success Criteria: Operation of software systems with NIFS simulator.

Comment: Will be performed during First NIFS Cool Down (4.2).

4.4 Laboratory Operation

Item: Demonstrate Operation in the Instrument Preparation Laboratory

Phase: VC1

Procedure: Operation of all NIFS mechanisms is demonstrated in the telescope software environment. Operation of the NIFS science detector with the Gemini Data Handling System is demonstrated. Basic science detector properties are characterized. Focal Plane Mask Wheel 0.1² diameter pin hole is imaged to confirm spectrograph focus. Operation of the NIFS OIWFS detector with the Telescope Control System is demonstrated. OIWFS test star is used to demonstrate operation of the OIWFS data path to the A&G IOC. Basic OIWFS detector properties are characterized. Interaction with Telescope Control System for slewing and offsetting are demonstrated. FITS header entries are checked.

Duration: 48 hours.

Personnel: Downing, Hart, Jarnyk, McGregor, Young.

Prerequisites: Successful completion of 4.2 and 4.3. Access to telescope systems.

Success Criteria: Control of NIFS mechanisms via Telescope Control System. Functioning data path from NIFS science detector to data archiving by the Data Handling System. Functioning Quick Look Displays. Functioning data path from OIWFS detector to Acquisition & Guiding IOC. Control of telescope slewing and offsetting via NIFS user interface software.

Comment:

4.5 Instrument Installation

Item: Install NIFS Instrument on Telescope

Phase: VC1

Procedure: Disconnect instrument from Preparation Laboratory facilities. Transport instrument to telescope. Mount instrument on Instrument Support Structure (ISS). Connect instrument to telescope facilities.

Duration: 12 hours.

Personnel: Dawson, Downing, Hart.

Prerequisites: Daytime access to telescope. Gemini maintenance staff.

Success Criteria: NIFS instrument mounted on ISS and connected to telescope facilities.

Comment:

4.6 Functionality Demonstration

Item: Demonstration of Basic NIFS Functionality

Phase: VC2

Procedure: Operation of all NIFS mechanisms is demonstrated on the telescope and via the NIFS user interface software. Control of NIFS science detector parameters is demonstrated via the NIFS user interface software. Control of NIFS OIWFS detector parameters is demonstrated via the NIFS user interface software. Control of the NIFS Quick Look Displays is demonstrated via the NIFS user interface software.

Duration: 12 hours.

Personnel: Dawson, Downing, Jarnyk, McGregor, Young.

Prerequisites: Successful completion of 4.5. Daytime access to telescope.

Success Criteria: Instrument functioning on ISS via NIFS user interface software.

Comment:

4.7 Configuration Time

Item: Time To Reconfigure The Instrument

Phase: VC2

Procedure: Configure instrument for a particular grating and science target. Measure time for maximal reconfiguration of the instrument for a different grating and a different science target.

Duration: 2 hours.

Personnel: Downing, McGregor, Young.

Prerequisites: Successful completion of 4.6. Daytime access to telescope.

Success Criteria: Individual NIFS mechanisms setting within 30 s, and a complete reconfiguration of the instrument achieved in < 1 min (REQ-OCD-0015).

Comment:

4.8 Science Detector Read Noise

Item: Optimize NIFS Science Detector Read Noise

Phase: VC2, VC4

Procedure: Measure NIFS science detector read noise. Modify detector grounding scheme to eliminate interference.

Duration: 4 hours (VC2), 4 hours (VC4).

Personnel: Downing.

Prerequisites: Successful completion of 4.6. Daytime access to telescope.

Success Criteria: NIFS science detector effective read noise < 10 e (REQ-OCD-0012).

Comment:

4.9 Science Detector Voltages

Item: Optimize NIFS Science Detector Operating Voltages

Phase: VC2, VC4

Procedure: Re-optimize NIFS science operating voltages in the telescope environment.

Duration: 8 hours (VC2), 8 hours (VC4).

Personnel: Downing

Prerequisites: Successful completion of 4.8. Daytime access to telescope.

Success Criteria: Optimized NIFS science detector performance.

Comment:

4.10 Science Detector Performance

Item: Document NIFS Science Detector Performance

Phase: VC2, VC3, VC4

Procedure: Measure NIFS science detector cosmetics, read out noise, gain, dark current, linearity, full well, persistence, and stability.

Duration: 12 hours (VC2), 12 hours (VC3), 12 hours (VC4).

Personnel: Downing

Prerequisites: Successful completion of 4.9. Daytime access to telescope.

Success Criteria: Documented NIFS science detector performance. Dark current < 0.1 e s^-1 pix^-1 (REQ-OCD-0013).

Comment:

4.11 OIWFS Detector Read Noise

Item: Optimize NIFS OIWFS Detector Read Noise

Phase: VC2, VC4

Procedure: Measure NIFS OIWFS detector read noise. Modify detector grounding scheme to eliminate interference.

Duration: 4 hours (VC2), 4 hours (VC4).

Personnel: Downing.

Prerequisites: Successful completion of 4.6. Daytime access to telescope.

Success Criteria: NIFS OIWFS detector effective read noise < 15 e.

Comment:

4.12 OIWFS Detector Voltages

Item: Optimize NIFS OIWFS Detector Operating Voltages

Phase: VC2, VC4

Procedure: Re-optimize NIFS OIWFS operating voltages in the telescope environment.

Duration: 8 hours (VC2), 8 hours (VC4).

Personnel: Downing

Prerequisites: Successful completion of 4.11. Daytime access to telescope.

Success Criteria: Optimized NIFS OIWFS detector performance.

Comment:

4.13 OIWFS Detector Performance

Item: Document NIFS OIWFS Detector Performance

Phase: VC2, VC3, VC4

Procedure: Measure NIFS OIWFS detector cosmetics, read out noise, gain, dark current, linearity, full well, persistence, and stability.

Duration: 12 hours (VC2), 12 hours (VC3), 12 hours (VC4).

Personnel: Downing

Prerequisites: Successful completion of 4.12. Daytime access to telescope.

Success Criteria: Documented NIFS science detector performance.

Comment:

4.14 Initial Calibrations

Item: Record Initial Calibration Frames

Phase: VC2, VC4

Procedure: Record a full set of calibration frames as described in §6.1 of the NIFS OCDD (SDN0003.01).

Duration: 6 hours (VC2), 6 hours (VC4).

Personnel: Downing, McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 4.10and 5.2. Daytime access to telescope.

Success Criteria: Valid NIFS calibration frames recorded.

Comment:

4.15 Wavelength Calibrations

Item: Derive Wavelength Calibrations For Each Grating

Phase: VC3

Procedure: Use IRAF to fit wavelength calibrations to each row of the NIFS data frames for each grating.

Duration: 3 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 4.14.

Success Criteria: Wavelength ranges as specified in Table 3 o the NIFS OCDD (SDN0003.01).

Comment: The specification of the wavelength calibration for each row is needed to finalize the Quick Look Display algorithm.

4.16 Distortion Calibrations

Item: Derive Distortion Calibrations For Each Grating

Phase: VC3

Procedure: Use IRAF to fit geometrical transformations in the spatial direction to frames obtained with the Ronchi mask in the NIFS Focal Plane Mask Wheel.

Duration: 3 hours (VC3).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 4.14.

Success Criteria: Spatial distortion along each spectrum < 1 pixel (REQ-OCD-0004.

Comment: The specification of how the slitlets map to a 3D data cube is needed to finalize the Quick Look Display algorithm.

4.17 Spectral Resolution

Item: Spectral Resolution And Its Variation Along The Spectrum

Phase: VC3

Procedure: Use IRAF to measure FWHM for emission lines at different positions along each spectrum for different slitlets.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 4.14.

Success Criteria: Spectral resolving powers ≥ 5000 in the J, H, and K bands and ≥ 4500 in the Z band (REQ-OCD-0006).

Comment:

4.18 Neutral Density Filter

Item: Calibrate Neutral Density Filter Attenuation

Phase: VC2

Procedure: Adjust GCAL flat field lamp to near saturation for minimum integration time without the NIFS neutral density filter. Measure several short exposures. Insert the NIFS neutral density filter. Measure several long exposures.

Duration: 2 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.2. Daytime access to telescope.

Success Criteria: NIFS able to accurately record data from point sources with K ³ 3 mag over its full field-of-view (REQ-OCD-0022).

Comment:

4.19 ISS Flexure

Item: Measure Flexure Between ALTAIR and NIFS External to NIFS

Phase: VC2, VC3, VC4

Procedure: Set the OIWFS Filter Wheel to the open aperture position. Position ALTAIR’s simulated star in the OIWFS field close to the OIWFS test star position. Measure relative positions of the two images for different telescope orientations. Derive ISS flexure from changes in relative position.

Duration: 2 hours (VC2), 2 hours (VC3), 2 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.1 and 6.1. Daytime access to telescope.

Success Criteria: Flexure below budget for 0.1 pixel per 15° change in orientation specification.

Comment:

4.20 NIFS Flexure

Item: Measure Flexure Between NIFS Science Detector and OIWFS Detector

Phase: VC2, VC3, VC4

Procedure: Position ALTAIR’s simulated star in the NIFS science field. Measure relative positions of the ALTAIR star in the NIFS science detector and the OIWFS test star in the OIWFS detector for different telescope orientations. Derive NIFS flexure from changes in relative position.

Duration: 2 hours (VC2), 2 hours (VC3), 2 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.1 and 6.1. Daytime access to telescope.

Success Criteria: Flexure below budget for 0.1 pixel per 15° change in orientation specification.

Comment:

5 Telescope System Verification

5.1 Functionality Demonstration

Item: Demonstration of Basic Telescope Functionality

Phase: VC1

Procedure: Control of telescope systems is demonstrated via the NIFS user interface software. Control of telescope slews and offsets are tested. Control of the ISS rotator position and deployment of the Science Fold Mirror are tested. Control of GCAL is tested.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist

Prerequisites: Successful completion of 4.5. Daytime access to telescope.

Success Criteria: Telescope systems controlled via NIFS user interface software.

Comment:

5.2 GCAL Lamp Intensities

Item: Measurement of GCAL Lamp Intensities

Phase: VC2

Procedure: Record flat field frames and frames for all arc lamps using each of the four NIFS gratings as described in the NIFS OCDD (SDN0003.01). Measure intensities and verify that they are within the useful operating range of the NIFS science detector for minimum integration times.

Duration: 6 hours.

Personnel: Downing, McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.1 and 4.6. Daytime access to telescope.

Success Criteria: Optimal calibration frames recorded in minimum integration time.

Comment:

5.3 Initial Field Acquisition

Item: Acquire First NIFS Target

Phase: VC2

Procedure: Slew telescope to target field. Deploy ISS science fold mirror. PWFS1 acquires guide star. Offset telescope 20²S. Scan OIWFS to locate science object. Offset telescope 20²N to center target in NIFS FOV. Adjust boresight using Idle Mode Quick Look Display. Offset OIWFS to locate OIWFS guide star. Select OIWFS as primary tracking reference. Focus telescope. Deploy AO fold mirror. AOWFS acquires its guide star. Reacquire target in NIFS FOV. Optimize ALTAIR servo loop parameters. Record first light exposure.

Duration: 6 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 4.14, 5.1, and 6.1. Nighttime access to telescope.

Success Criteria: First light image recorded.

Comment:

5.4 Cold Stop Alignment

Item: Check Alignment of Science Instrument Cold Stop

Phase: VC2, VC4

Procedure: Center a star in the NIFS FOV and record a Run Mode exposure. Rotate the ISS science fold mirror to the maximum clockwise position (~ 0.3 of the secondary mirror diameter), offset the telescope to re-center the star, and record a Run Mode exposure. Repeat in increments of 0.05 of the secondary mirror diameter back to the nominal center position. Repeat in the counter-clockwise rotation direction. Repeat in the orthogonal direction using the ISS science fold mirror tilt. Measure the signal strengths in the seven exposures offset in each direction. Fit straight lines to each set of seven points to infer the ISS science fold mirror orientation where the image of the telescope exit pupil coincides with the NIFS cold stop. Repeat at different attitudes of the telescope.

Duration: 2 hours (VC2), 2 hours (VC4).

Personnel: Conroy, McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Image of telescope exit pupil coincident with NIFS cold stop to < 1% (REQ-FPR-0002) for any attitude of the telescope (REQ-FPR-0200).

Comment: The area of overlap of two offset circles of the same radius is inversely proportional to the offset. We are attempting to measure the angular offset which gives peak signal by fitting line segments to the linear decline on both sides of this peak. The signal should drop to ~ 62% of the peak value at offsets of ±0.3 of the secondary mirror diameter. These line segments should have slopes of ~ ±1.3 (signal fraction per diameter). The uncertainty in the peak value for each line segment is ~ σ/√N, where σ is the fractional error in the measured signals and N is the number of equally-spaced samples contributing to the fit. This corresponds to an offset uncertainty of ~ σ/√N/1.3, which should be < 1% of the secondary mirror diameter. This can be achieved with ~ 7 samples if the individual star signals are measured to ~ 3%

5.5 Offset From Rotator Axis

Item: Determine NIFS Boresight Offset From Rotator Axis

Phase: VC2, VC4

Procedure: Center target in NIFS FOV. Rotate ISS by 120°. Determine offset (r,q) from rotator axis. Enter values into telescope pointing model.

Duration: 1 hour.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: NIFS boresight referenced to ISS rotator axis to an accuracy of < 0.1².

Comment:

5.6 Pointing Accuracy

Item: Measure NIFS Pointing Accuracy over Sky

Phase: VC2, VC4

Procedure: Slew to targets over whole sky. Record initial position. Center in NIFS FOV. Record pointing errors.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.5. Nighttime access to telescope.

Success Criteria: RMS pointing error determined.

Comment:

5.7 Image Quality

Item: Measure Image Quality Over Sky

Phase: VC2, VC3, VC4

Procedure: Slew to targets over whole sky. Optimize ALTAIR performance. Record images with 60 seconds total integration time to average seeing fluctuations.

Duration: 4 hours (VC2), 8 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Image FWHM with ALTAIR determined over the whole sky.

Comment:

5.8 Spatial Pixel Scale

Item: Measure Spatial Pixel Scale Parallel and Perpendicular To Slitlets

Phase: VC2

Procedure: Slew to a star. Record frame. Offset parallel to slitlets. Record frame. Repeat several times. Repeat with offsets perpendicular to slit.

Duration: 2 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: NIFS slit widths of 0.103²±0.010² and spatial scale of 0.040²±0.005² (REQ-OCD-0003).

Comment:

5.9 Astrometric Accuracy

Item: Measure Astrometric Accuracy of NIFS Images On The Sky

Phase: VC2, VC3

Procedure: Slew to an astrometric field such as a globular cluster or a field containing many Hipparcos stars. Record target and sky frames. Reformat data to a cube using transformations defined from the wavelength calibration and the Ronchi mask calibration. Spectrally compress cube to an image on the sky. Measure relative positions of stars in the image and compare to astrometric positions.

Duration: 2 hours (VC2), 4 hours (VC3).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: RMS astrometric accuracy in reconstructed image on the sky is determined.

Comment:

5.10 Instrument Flexure

Item: Measure NIFS Instrument Flexure

Phase: VC2, VC3, VC4

Procedure: Slew to a target near the horizon. Center in NIFS FOV. Record Run Mode exposures at various ISS rotator orientations. Measure the position of the object in each image.

Duration: 3 hours (VC2), 3 hours (VC3), 3 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Instrument Flexure < 0.1 pixel per 15° change in orientation requirement (REQ-FPR-0201).

Comment:

5.11 System Efficiency

Item: Measure System Efficiency For Each Grating

Phase: VC2, VC3, VC4

Procedure: Slew to a smooth spectrum flux standard star. Record spectra with each grating with and without using ALTAIR. System efficiency is calculated from the measured signals. Limiting bright magnitudes are calculated from the system efficiency and the know science detector well depth.

Duration: 2 hours (VC2), 2 hours (VC3), 2 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Total system throughput, excluding ALTAIR, ³ 15% (REQ-OCD-0007). Total system throughput, including ALTAIR, is determined.

Comment:

5.12 Background Brightness

Item: Measure Background Brightness For Each Grating

Phase: VC2, VC3, VC4

Procedure: Slew to blank sky. Record bias frames. Record spectra of one hour duration with each grating. Derive sky brightnesses for each grating using the instrumental responsivities measured in 5.11.

Duration: 3 hours (VC2), 2 hours (VC3), 3 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: External background brightness determined. Internal instrumental background shown to be less than either the external background or the detector dark current, whichever is greater (REQ-OCD-0008).

Comment:

5.13 Instrumental Sensitivities

Item: Measure Instrumental Sensitivities For Each Grating

Phase: VC2, VC3, VC4

Procedure: Slew to a faint target of known brightness. Record spectra of one hour duration with each grating. Measure the signal-to-noise ratio per pixel achieved to derive instrumental sensitivities.

Duration: 8 hours (VC2), 8 hours (VC3), 8 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Extended sources with K band surface brightness of 13.5 mag arcsec^-2 and emission-line sources in the K band with surface brightness of 1.5´10^-22 W cm^-2 arcsec^-2 detected in 1800 s with signal-to-noise ratio of 10 at 0.1²´0.1² spatial resolution (REQ-OCD-0021).

Comment:

5.14 Limiting Signal-To-Noise Ratio

Item: Determine Where Systematic Noise Sources Limit Signal-To-Noise Ratio

Phase: VC2, VC3, VC4

Procedure: Slew to a faint target of known brightness. Record eight spectra of one hour duration each with the H grating. Measure the signal-to-noise ratio per pixel achieved after summing 1, 2, 4, and 8 frames.

Duration: 10 hours (VC2), 8 hours (VC3), 10 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Limiting SNR determined.

Comment: SNR should reduce as T^1/2 over the longest conceivable integration time.

5.15 Highest Obtainable S/N Ratio

Item: Measure Highest Obtainable Signal-To-Noise Ratio

Phase: VC2, VC3, VC4

Procedure: Slew to a smooth spectrum flux standard. Record multiple spectra of appropriate duration. Intersperse with spectra of a second smooth spectrum flux standard for atmospheric absorption correction. Compare the measured signal-to-noise ratios with theoretical signal-to-noise ratio improvement.

Duration: 8 hours (VC2), 8 hours (VC3), 8 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Highest obtainable SNR is determined.

Comment: Divided spectrum should have a signal-to-noise ratio > 100 in order to measure weak spectral features against a strong continuum.

5.16 OIWFS Repeatibility

Item: OIWFS Setting Repeatibility

Phase: VC2, VC4

Procedure: Slew to a target. Select OIWFS as the primary tracking reference. Center star in NIFS FOV. Record a Run Mode exposure. Offset OIWFS so the star moves 10″ along the NIFS slitlets. Offset OIWFS back to original position. Record a Run Mode exposure. Repeat for positive and negative offsets of different lengths. Measure star positions on all images. Calculate OIWFS repeatability as the standard deviation of the star positions.

Duration: 4 hours (VC2), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: OIWFS has a positioning repeatability of < 0.005² (REQ-OCD-0014d).

Comment: Offsets are in the direction of the NIFS slitlets so that the image centroids are calculated using the 0.04″ pixels in that direction.

5.17 OIWFS Offsetting Accuracy

Item: Measure Accuracy of OIWFS In Performing Offsets

Phase: VC2, VC4

Procedure: Slew to a target. Select OIWFS as the primary tracking reference. Center star in NIFS FOV. Record a Run Mode exposure. Offset OIWFS so the star moves 1.00″ along the NIFS slitlets. Record a Run Mode exposure. Offset OIWFS so the star moves -2.00″ along the NIFS slitlets. Repeat several times in increments of 0.5″ along the NIFS slitlets. Measure star centroids on all images. Calculate OIWFS offsetting accuracy by comparing image displacement in pixels to the requested value using the known pixel scale along the NIFS slitlets.

Duration: 4 hours (VC2), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: OIWFS offsetting linearity determined for offsets between 0.5″ and 2.0″. OIWFS inferred to perform offsets of 0.05″ with an accuracy of < 0.005″ (REQ-OCD-0014c).

Comment: Offsets are in the direction of the NIFS slitlets so that the image centroids are calculated using the 0.04″ pixels in that direction.

5.18 OIWFS Responsivity

Item: Measure OIWFS Instrumental Responsivity For Each Filter

Phase: VC2, VC3, VC4

Procedure: Slew to a photometric flux standard star. Record OIWFS images through each filter. Instrumental responsivity is calculated from the measured signals. Limiting bright magnitudes are calculated from the instrumental responsivity and the know OIWFS detector well depth.

Duration: 2 hours (VC2), 2 hours (VC3), 2 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: NIFS OIWFS has equal or better responsivity to NIRI OIWFS.

Comment:

5.19 OIWFS Field-Of-View

Item: Measure Size of OIWFS Useful Field-Of-View With ALTAIR

Phase: VC2, VC3

Procedure: Slew to a photometric flux standard star using ALTAIR. Offset telescope in a grid to place star near extremities of ALTAIR field. Record OIWFS images of the star at each grid position. Repeat using a grid sampling near the NIFS pick off mirror and its support structure.

Duration: 2 hours (VC2), 4 hours (VC3).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: OIWFS guide star acquisition field determined.

Comment: Accurate knowledge of the NIFS field size with ALTAIR is need for guide star selection.

5.20 OIWFS Flexure

Item: Measure Flexure of OIWFS With Respect to ALTAIR

Phase: VC2, VC3, VC4

Procedure: Slew to a smooth spectrum flux calibrator. Use AOWFS for tip-tilt corrector. Measure OIWFS guide star position. Repeat through night at a range of hour angles either side of the meridian.

Duration: 4 hours (VC2), 8 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Flexure between ALTAIR and the NIFS OIWFS is determined.

Comment: OIWFS guide stars will normally not be needed if flexure between ALTAIR and the OIWFS is less than the 0.1 pixel per 15° change in orientation specification.

5.21 OIWFS Limiting Magnitude

Item: Measure OIWFS Limiting Magnitudes For Each Filter

Phase: VC2, VC3, VC4

Procedure: Slew to a faint OIWFS guide star of known brightness. Measure RMS variation in centroid position for 100 OIWFS frames. Repeat for a range of OIWFS guide stars of different magnitudes. Determine at what OIWFS guide star magnitude the RMS centroiding error exceeds the diffraction FWHM for each OIWFS filter.

Duration: 4 hours (VC2), 4 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: OIWFS able to centroid on stars with K < 19 mag in 10 s exposures and do tip-tilt/focus correction on stars with K < 15 mag in 0.1 s exposures (REQ-OCD-0014e.

Comment:

5.22 Ghost Intensity

Item: Ghost Image Intensity

Phase: VC2, VC3, VC4

Procedure: Slew to a bright star. Record flat field and sky frames before and after recording deep spectra of the bright star to quantify ghost images due to the bright star. Record bias and flat field frames before and after recording deep sky spectra to quantify ghost images due to sky emission lines.

Duration: 4 hours (VC2), 4 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Ghost images at a level below 10^-4 at radii > 2² from parent image (REQ-OCD-0010).

Comment:

5.23 Scattered Light

Item: Scattered Light Intensity

Phase: VC2, VC3, VC4

Procedure: Record bias and flat field frames before and after recording a deep H band sky spectrum. Scattered light intensity is determined from broad wings on profiles of bright OH sky emission lines.

Duration: 4 hours (VC2), 4 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Scattered light < 10% of total light entering NIFS instrument in spectral bandpass of interest (REQ-OCD-0009).

Comment:

5.24 Radial Velocity Stability

Item: Radial Velocity Measurement Stability

Phase: VC2, VC3, VC4

Procedure: Obtain high signal-to-noise ratio spectra every night for at least two systems with known constant radial velocity or with well determined radial velocity variations. Bracket these observations with arc lamp spectra obtain less than 1 hr before and after the radial velocity measurement. Determine wavelength calibration via arc lamp and sky emission line spectra. Measure radial velocities of spectral features.

Duration: 8 hours (VC2), 8 hours (VC3), 8 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: RMS radial velocity stability is determined.

Comment: Radial velocities should be accurate to < 5 km s^-1 if the flexure requirement (REQ-FPR-0201) is met and radial velocities are referred to arc lamp spectra taken within 1 hr of the science observation.

5.25 J Band Spectroscopy

Item: Demonstrate J Band Emission Line Science Observation

Phase: VC2

Procedure: Record J band spectrum of H I Pb and [Fe II] 1.257 mm in the inner Narrow Line Region of a Seyfert Galaxy with resolved radio structure.

Duration: 5 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Spatial-resolved emission-line profiles recorded.

Comment:

5.26 K Band Spectroscopy

Item: Demonstrate K Band Continuum Source Science Observation

Phase: VC2

Procedure: Record K band spectrum of 2.29 mm CO (2-0) stellar absorption bands in a nearby galactic nucleus or fields in the Galactic Center.

Duration: 5 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Stellar velocity dispersion determined to radial distance of 0.1².

Comment:

5.27 Occulting Disk Usage

Item: Define Safe Observing Procedure Using Occulting Disk

Phase: VC2

Procedure: Slew to a smooth spectrum flux standard. Experiment with procedures for accurately centering the star on the Focal Plane Mask Wheel occulting disks without relying on the NIFS science detector output. Slew to a very bright star and use the procedure to measure spectra in the vicinity of the bright occulted star.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope.

Success Criteria: Procedure for using occulting disks with minimal remnance is defined. NIFS able to accurately record data at radii > 0.25² from point sources with K ³ 3 mag (REQ-OCD-0011).

Comment:

6 ALTAIR System Verification

6.1 Functionality Demonstration

Item: Demonstration of Basic ALTAIR Functionality

Phase: VC1

Procedure: Control of ALTAIR systems is demonstrated via the NIFS user interface software. Deployment of the AO Fold Mirror is tested. Control of the ALTAIR shutters is tested. Control of AOWFS is tested. Control of the AO servo loop parameters is tested.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist

Prerequisites: Successful completion of 4.5. Daytime access to telescope.

Success Criteria: ALTAIR systems controlled via NIFS user interface software.

Comment:

6.2 Strehl Ratio Degradation

Item: Measure Degradation in Strehl Ratio Due to NIFS Optics

Phase: VC2, VC3, VC4

Procedure: Slew to a smooth spectrum flux standard. Record spectrum of star. Measure image FWHM and central intensity in Run Mode Quick Look Display spectrally compressed image display. Image same star with NIRI high resolution camera. Compare NIFS and NIRI image parameters.

Duration: 4 hours (VC2), 4 hours (VC3), 4 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3. Nighttime access to telescope. NIRI mounted on ISS and available for observing.

Success Criteria: Strehl ratio degradation due to NIFS optics < 0.80 (REQ-OCD-0005).

Comment:

7 GPOL System Verification

7.1 Functionality Demonstration

Item: Demonstration of Basic GPOL Functionality

Phase: VC1

Procedure: Control of GPOL system is demonstrated via the NIFS user interface software. Deployment of GPOL calibrators is tested. Control of the GPOL wave plate is tested.

Duration: 2 hours.

Personnel: McGregor, Gemini Instrument Scientist

Prerequisites: Successful completion of 4.5. Daytime access to telescope.

Success Criteria: GPOL systems controlled via NIFS user interface software.

Comment:

7.2 Data Acquisition

Item: Synchronous GPOL Data Acquisition With NIFS

Phase: VC2

Procedure: Perform a spectropolarimetry observation of an object with known polarization degree and orientation. Data acquisition is synchronized with control of the GPOL half-wave plate.

Duration: 4 hours.

Personnel: McGregor, Gemini Instrument Scientist.

Prerequisites: Successful completion of 5.3 and 7.1. Nighttime access to telescope.

Success Criteria: Spectropolarimetry procedure correctly measures polarization degree and orientation.

Comment:

7.3 Sensitivity

Item: Determine Faint Sensitivity Limit For NIFS Spectropolarimetry

Phase: VC2, VC3, VC4

Procedure: Perform a spectropolarimetry observation of a faint object with known polarization degree and orientation. Measure signal-to-noise ratio achieved. Infer faint limiting magnitude.

Duration: 6 hours (VC2), 4 hours (VC3), 6 hours (VC4).

Personnel: McGregor, Gemini Instrument Scientist

Prerequisites: Successful completion of 7.2. Nighttime access to telescope.

Success Criteria: Spectropolarimetry sensitivity quantified and limiting factors identified.

Comment:

8 Schedule

The schedule for the Integration and Installation (VC1) and System Evaluation (VC2) phases of the Verification and Commissioning Plan is shown in Figure 1. The schedule assumes day staff work a nine hour day (09:00-12:00, 13:00-16:00,18:00-21:00) and a seven day week. The schedule assumes that the telescope will be available for functional tests during daytime in the period after instrument installation and before NIFS is scheduled for nighttime observations. Nighttime observations begin with WBS 4.1. Scheduled access to the telescope is required at this time. The Verification and Commissioning schedule assumes night staff work a twelve hour night (18:00-06:00) and a seven night week.

The System Evaluation phase will be followed by a Performance Assessment phase (VC3) lasting approximately three weeks. The Commissioning Team members will return to their home institutions during this phase. The Performance Assessment phase will be followed by the System Optimizations phase. Scheduled time on Gemini North will be required for the System Optimization phase. The duration of the System Optimization phase will depend on the extent of the changes made to NIFS since the System Evaluation phase; if major changes will necessitate a repeat of most measurements made during the System Evaluation phase leading to a System Optimization duration of approximately two weeks.

Figure 1: Plan for the Integration and Installation (VC1) and System Evaluation (VC2) phases of the NIFS Verification and Commissioning Plan. The System Evaluation phase is followed by the Performance Assessment phase (VC3) with a duration of approximately three weeks and the System Optimization phase (VC4) having a duration of up to two weeks.

Appendix A: List of Figures

Figure 1	Paste

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