Detectors

General

The current fleet of CFHT science detectors consists of Loral 3, Stis 2, Redeye Wide, and the Reticon diode array. We currently have 2 2k x 2k thinned ccd's and an engineering grade Hawaii IR array in dewars awaiting tests.

A Residual Gas Analyzer has been added to the Waimea dewar vacuum system. The RGA is proving to be an extremely valuable tool for distinguishing between leaks and outgassing and for measuring their relative contributions to dewar vacuum loss.

STIS2

This 21 µm, thinned, 2k x 2k detector has quickly become the work-horse device. Some initial noise problems during the first run were promptly repaired. A 7 minute readout time was an unpopular feature when this detector was offered initially. Readout has since been upgraded to 2 minutes without significant performance degradation. We are looking into implementing an even faster mode for non-science applications. STIS2 is now offered for use on all CFHT instruments.

UH 8k

The UH 8k detector continues to be used productively at the Prime Focus. There have been a significant number of problems with shutter reliability. During the September run the shutter motor drive shaft had to be replaced - an operation which required the removal of the camera from telescope. Shutter double firing with both shutter leaves actuating at once or in rapid succession resulted in several lost exposures.

Delivery of the camera at the last minute before the observing run has made software integration into the CFHT system more problematic than anticipated. CFHT staff have travelled to IfA with a CFHT computer in order to support the UH software using CFHT facilities. The initial agreement to use the camera software running under Solaris has not panned out so far, although we are still aiming at this target since operation under Solaris will be needed in the longer term.

CFHT received and installed the S-Bus interfaces for the 8k x 12k camera which are currently being used to support runs using the 8k camera. The interfaces are working well.

CFHT has ordered a B filter for use with the 8k camera.

Occasional problems with scattered light appear to be due to bright stars catching the edge of the last lens cell in the WFC. We are currently waiting for data from observers so that we can evaluate the effect. Vignetting by the guide probe has been a problem. At the moment we have not been able to provide the observer with an unambiguous range of vignetting-free guide probe positions. We are working on generating these numbers now.

All scientific data from UH8k runs are saved on exabyte. True archiving will take place later.

KIR (1k x 1k Rockwell HgCdTe array camera for AOB)

The KIR contract with the University of Montreal was signed in mid July. We are currently expecting delivery to CFHT in March, 1997. The SDSU 4-channel controller was ordered at the end of May and delivered to Toulouse in August. The array controller (SDSU), host computer (Cassini), HP workstation, and preliminary software have been shipped to Observatoire Midi Pyrenees (OMP) where modifications will be made to run the KIR camera system.

A preliminary design review of the dewar has been held, and work has commenced on the optics and software for the system. A final design review is expected in November. We have received the 1K x 1K HgCdTe engineering array from Rockwell and are expecting the science array before the end of the year.

Redesign and reimplementation of the CCD gen III server to allow for support of VME memory access control, data descrambling and raw and reference image data subtraction have largely been completed.

Redeye Wide

Problems with a noisy quadrant early in the year were fixed with the fabrication and installation of a new CFHT preamp. Gain with a new preamp is 15 e-/ ADCU and noise is 40 e- now set by detector noise limit. Use of the camera with a new controller and Gen III v 4 software needs to be completed. An initial problem with an occasional extra zero pixel prevented the system being used for the FTS Bear run in July. In the mean time Redeye use continues with the old controller/preamp system.

Redeye Narrow Upgrade (1 quadrant of the Hawaii 1k x 1k Rockwell engineering device)

The detector MUX was received in mid-May - the engineering device grade in mid-July. A preamp for this camera has been fabricated as a prototype for KIR. The upgraded dewar assembly which permits use of any detector quadrant was received in early June. A few small vacuum leaks were solved in June as was wiring of the bias board. Remaining work includes installation of the new preamp and mounting the fanout board and array into the dewar. Testing and optimization will follow.

This detector was intended as an interim AOB detector until KIR could be delivered. In a recent review of project time lines, given the past and expected continued success of MONICA-based AOB runs. and the likely life time for use of Redeye Narrow, we have migrated the project into acting as a CFHT test bed for KIR support and away from being tied to a specific observing run.

CFH 12 k / Lincoln Lab

The camera contract with the University of Hawaii was signed in mid July. We currently expect the system to be available for population with CCD's by February 1997. We have also entered into a shared cost development agreement with Gerry Luppino on software development for a 2nd generation SDSU controller. This controller will allow for greater readout speed and, as a bonus, will give us 12 analog channels. There is room inside the dewar for twelve devices. If we can acquire twelve devices we will install all of them on the focal plane.

The camera design has been upgraded with the addition of chip mounts and CCDs for potential in-dewar autoguiding. Electronics and control for such a guider facility have not been addressed.

The S-Bus interfaces for the project have been delivered and are being used at CFHT to support the UH 8k camera. The interfaces are working well.

UBC Loral 4k x 200 thinned CCD

We have decided to continue the current loan agreement with Gordon Walker at UBC indefinitely since development of this device as a CFHT project is not in our current planning, and since Gordon points out that there are some concerns about the long term life of the devices. The project for development of a dual array camera holding one thinned and one thick device has been put on hold pending operational commissioning of 2 more thinned 2k square devices.

LORAL 5

Loral 5 is the next thinned CCD awaiting commissioning. The device, mounted in a dewar, was delivered by Gerry Luppino two weeks ago.

OSIS IR

The OSIS IR camera, given high priority by the SAC, has progressed moderately. We entered into a purchase agreement with Rockwell at the beginning of August. Since then we have had discussions with University of Montreal regarding development of the camera. We have started development of the contract and technical specifications but do not at the moment have a clear date for completion.

Gen III v 4

A preliminary version of this software has been implemented for both the BEAR mode of RedeyeW and for the KIR camera. This software replaces much of the old, problematic acquisition system with a more streamlined system which uses VME memory in the host computer. We have had preliminary design reviews on this system and hope to implement the software on all CCD and infrared camera systems as soon as possible.

Orbit1

This device is officially dead. Mike Lesser, University of Arizona, was unable to remove the contamination from the surface of the device after the anti-reflection coatings were removed. It remains unknown exactly how the contamination was acquired.

Titan and Cassini

These CCD host computers have been upgraded with new software and hardware and are configured to be identical. Cassini has been shipped to OMP in France. Both hosts now have the Chrislin VME memory and 4 GByte hard drives for local image storage. The prototype GenIII V4 software has been installed on both systems. Continued software development will take place on Titan at CFHT headquarters.





tmca@cfht.hawaii.edu
Copyright © 1997, Canada-France-Hawaii Telescope Corp. All rights reserved.