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AUSTRALIAN
NATIONAL UNIVERSITY System Design Note 7.00 Created: 5 April 2000 Last modified: 7 April 2000 |
NIRI DUPLICATION WORK PACKAGES
Peter J. McGregor
Research School of Astronomy
and Astrophysics
Institute of Advanced
Studies
Australian National
University
Revision History
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Revision No. |
Author & Date |
Approval & Date |
Description |
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Revision 1 |
Peter J. McGregor 26 October 1999 |
John Hart 11 November 1999 |
Original document. |
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Revision 2 |
Peter J. McGregor 06 April 2000 |
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Reformatted for Word 2000. |
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Contents
5 On-Instrument
Wavefront Sensor
15 Contracted
Construction by RSAA
1 Purpose
The Research School of Astronomy and Astrophysics (RSAA) of the Australian National University wish to explore ways in which the Institute for Astronomy (IfA) of the University of Hawaii might contribute to the construction of the Gemini Near-infrared Integral Field Spectrograph (NIFS). This document describes work packages that may be subcontracted to IfA.
2 Applicable Documents
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Source |
Title |
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3 Introduction
The Gemini Near-infrared Integral-Field Spectrograph (NIFS) is being designed by the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University. NIFS will use duplicates of the Gemini Near-Infrared Imager (NIRI) cryostat, On-Instrument Wavefront Sensor (OIWFS), and control system. NIRI has been designed and constructed at the Institute for Astronomy (IfA) of the University of Hawaii. It is intended that the bulk of the NIRI duplication work for NIFS will be performed by the IfA. The NIFS Conceptual Design Study Work Scope stipulates that such work will be performed by IfA as a subcontract from RSAA. The NIRI components that are required for NIFS are described below.
4 Cryostat
NIFS will use a duplicate of the NIRI cryostat including closed cycle coolers, “V” struts, optical bench, dewar window, and dust cover. The optical bench will be machined to accommodate the OIWFS on one side and the NIFS science instrument on the other. Requirements for mounting the NIFS science instrument will be made available to IfA as the design progresses. The external surfaces of the cryostat will be machined to accommodate the OIWFS detector controller and the NIFS science detector controller. The latter will be an SDSU-2 controller, unlike NIRI.
NIFS will use either a duplicate of the NIRI focal plane mask wheel, or a smaller substitute wheel, to hold occulting disks and calibration masks. RSAA and IfA will agree on a suitable approach to this modification. IfA will manufacture the wheel. RSAA will supply the wheel contents.
NIFS will not use the NIRI science fold mirror or its drive mechanism. Instead, RSAA will design a structure for mounting a fixed fold mirror that accommodates the fixed 3.1²´3.3² NIFS science field-of-view.
IfA will consider moving the location of the inner O-ring grooves from the front and back vacuum jacket components onto the VJ center section in order to ease assembly of NIFS.
5 On-Instrument Wavefront Sensor
NIFS will use a duplicate of the NIRI OIWFS. IfA will duplicate the OIWFS and supply all necessary filters, Hartmann-Shack prisms, motors, encoders, detector controller, and OIWFS detector.
6 Mechanism Control System
NIFS will use a duplicate of the NIRI mechanism control system. The mechanism control system will be required to control the focal plane mask wheel, the NIFS science filter wheel, the NIFS grating wheel, and the NIFS science detector focus mechanism, as well as all OIWFS functions, and the cryostat dust cover mechanism. The mechanism control system will not be required to control a science fold mirror wheel. IfA will duplicate the mechanism control system and test its operation on the OIWFS.
It may be necessary to replace the obsolete Oregon Micro Systems VME8-8 stepper motor controllers with VME58-8 stepper motor controllers. Phytron advise that the Phytron ZSO MINI 42-40 stepper motor power stages should be replaced with Phytron SINCOS-L mini-step linear power stages. If SINCOS-L power stages are used, it will be necessary to change the 48 V output Kepco power supply to a ±8 V to ±21 V power supply compatible with the SINCOS-L linear power stages.
It should be possible to control all of the NIFS OIWFS and science instrument mechanisms, except the Environmental Cover, with one VME58-8 8-channel stepper motor controller. The stepper motor driving the Environmental Cover could be replaced by a DC motor controlled through two spare channels on the XYCOM digital IO board. RSAA and IfA will agree on a suitable solution.
Some Input-Output Controller (IOC) boards may be supplied to RSAA by Gemini prior to construction commencing.
7 Temperature Control System
NIFS will use a duplicate of the NIRI temperature control system. The NIFS science detector will be a Rockwell HAWAII-2 array operated at ~ 65 K, unlike NIRI which uses an SBRC ALADDIN array operating at lower temperature. The NIFS science detector may need to be stable to ±1 mK over the maximum integration time of ~ 1 hr. RSAA and IfA will agree on how this can be achieved.
8 Electronics Racks
NIFS will use a duplicate of the Electronics Rack Support Frame used in NIRI to mount the electronics racks supplied by Gemini. RSAA and IfA will agree on how the electronics racks will be populated with control system electronics and detector control electronics, and how power and heat will be managed. IfA will manufacture the Support Frame, mount the Gemini-supplied electronics racks on the frame, and install the mechanism and temperature control system electronics in the electronics racks.
9 Testing
IfA will test the NIFS cryostat, OIWFS, temperature control system, and mechanism control system to the fullest extent possible before shipping the unit to RSAA. The proposed division of work is such that IfA should be able to deliver a fully tested and operational instrument to RSAA, minus the NIFS science instrument package.
10 Quality of Work
IfA will perform all work to the standards normally required by the International Gemini Project Office (IGPO) and applied to NIRI.
11 Acceptance Tests
IfA will perform acceptance tests on the operational unit as required by RSAA.
12 Documentation
IfA will supply RSAA with the same level of documentation as required by IGPO for NIRI.
13 Commissioning
RSAA will be responsible for commissioning the completed NIFS instrument on the Gemini telescope.
14 Schedule
IGPO requires that an aggressive schedule be adopted in order to commission NIFS on Gemini North as soon as possible. To this end, IfA must complete all construction, testing, and verification of NIFS components and ship the unit to RSAA by 1 July 2001.
15 Contracted Construction by RSAA
RSAA mechanical, optical, and electronic workshops have considerable experience in the construction of precision astronomical instruments. Where external contracted construction of such modules is sought by IfA for this project, RSAA will be given the opportunity to bid.