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Astronomical Data Analysis Software and Systems IV
ASP Conference Series, Vol. 77, 1995
R. A. Shaw, H. E. Payne, and J. J. E. Hayes, eds.
The Array Limited Infrared Control Environment
P. N. Daly and A. Bridger
Joint Astronomy Centre, 660 N. A'oh¯ok¯u Place, Hilo HI 96720
D. A. Pickup and M. J. Paterson
Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, Scotland
Abstract. This paper describes the recently commissioned Array Lim­
ited Infrared Control Environment (ALICE), used to control a new 256 2
array imager, IRCAM3, on UKIRT. Future plans, including the delivery
of a second ALICE to upgrade the UKIRT long­slit spectrometer, CGS4,
are also discussed.
1. Introduction
Infrared astronomy was revolutionized in the 1980s by the advent of array de­
tectors. One of the first such imaging cameras in regular operation was IRCAM
(McLean et al. 1986), followed by the array spectrometer CGS4 (Mountain et
al. 1990), both of which were commissioned onto the 3.8 m United Kingdom
Infrared Telescope (UKIRT) on Mauna Kea, Hawaii. The control electronics of
both these systems, however, were geared to driving the smaller SBRC 62 \Theta 58
InSb array. What was needed was a flexible and extensible system capable of
driving the new generation of arrays to the limits of their performance, hence
the term Array Limited Infrared Control Environment (ALICE).
Built at the Royal Observatory in Edinburgh (ROE), ALICE forms the
backbone of the program to upgrade both IRCAM and CGS4 to SBRC 256 2
InSb arrays. The ALICE design allows it to operate under a wide range of
conditions such as high resolution low background near infrared spectroscopy,
real­time shift­and­add image sharpening, and broad­band thermal imaging. To
date, the first ALICE has been commissioned on the telescope and the new
instrument, IRCAM3, saw first light on 1994 April 8 UT.
2. The Array Control System
The array control system (Pickup et al. 1993) applies well defined, and well con­
trolled, bias and clock voltages to the array, and is also responsible for clocking
the appropriate waveform to trigger read, reset, or read­reset operations. It also
obtains time stamps from the UKIRT satellite clock and is able to control the
secondary mirror in synchronization with the observations. All of these opera­
tions may be manipulated under software control from the user interface, thus
giving the system considerable flexibility.
1

2
AIM
ALD
TEL
MOT
ald_nb
va_nb
VAX
aim_nb
TIM
IOC IOS
WFG
BDS
TRANSPUTERS
core
graphics
Input
Speckle
VMS­ADAM
Occam
Transputer
ADAM
256x256
Array
VA
ALF
support
config
Video Screen
ALICE Instrument
Manager
ALICE
Filing task
VAX­ALICE
Control task
NDFs
ALICE
D­task
IRCAM Motors
Telescope
Control
System
TRAMs
Figure 1. The ALICE Software Map.
The array control system software operates under the transputer ADAM
environment (Kelly et al. 1993), and was originally written in parallel for­
tran, although this will be replaced by a C version when the second ALICE is
commissioned. The tasks comprise the time stamping process (TIM), the I/O
controllers (IOC and IOS), and the waveform generator (WFG), as shown in
Figure 1. The WFG is initialized with full frame read, reset, and read­reset
waveforms---other waveforms, for sub­array reads and so forth, are downloaded
as required.
The waveform generator hardware includes an Inmos T805­25 transputer
with 16 MB of DRAM. The waveform memory has 16 banks of 256k \Theta 32­bit
field memory. Each of the 32 bits of the waveform handles one clock signal (three
of which are reserved for system use). Moreover, any of the 16 banks can hold a
single waveform sufficient to drive a full 256 2 array. Banks can also be read out
seamlessly so that, if necessary, a waveform can be loaded across several banks.
In this fashion, larger arrays should easily be accommodated as they become
available.
3. The Bulk Data System
The bulk data system (BDS) supports the bi­directional transfer of data between
ALICE and the host system at ¸50 kB s \Gamma1 . Thus a full 256 2 4­bytes pixel \Gamma1
frame takes ¸5 s to transfer. Four MB of on­board RAM are used to buffer the
data to allow asynchronous acquisition of new data.

3
The bi­directional nature of the data transfer allows data to be passed up
to the host computer and, for example, bad pixel masks, color tables, or back­
ground frames to be passed down to the transputer sub­system when required by
the video display system. The BDS also handles the downloading of waveforms
to the WFG when required to trigger different reads of the array and the trans­
puter ADAM messaging traffic. Messages between the host computer (a VAX
in the present application), are routed through a B300 TCP­linkbox (ethernet
gateway).
4. The Data Acquisition System
The data acquisition system controls the analog conditioning of signals from
the array, conversion to digital inputs for the INMOS link adaptors via ADCs
(14­bit, 2 mega­samples s \Gamma1 ), and for the collection and re­assembly of the full
256 2 image via a transputer network. Several frames may be coadded to form an
integration before transmission to a host computer or local disk. There is also
a video display system that updates at ¸2 Hz, that can show either the current
integration or both the current integration and the coadded image side by side,
along with some simple image analysis (peak pixel in x, y, brightness, etc.).
ALICE makes extensive use of transputers (? 24), mainly T805s with 2
MB of memory each. The 16 input processors are hardwired as a pipeline on
the motherboard so each processor, during normal operation, sees every 16th
pixel from the array. The ``core'' process running on a single transputer acquires
the data from the pipeline and re­assembles the data into full frames. A speckle
option has recently been introduced using fiber­optic TRAMs that can ``spurt''
the data to a local (SCSI) disk directly for (very) fast acquisition. The transputer
data acquisition sub­system is programmed in Occam and the bootable may be
downloaded from either a Sun or a VAX.
5. Performance
Laboratory tests have shown that ALICE is capable of sustaining data rates for
256 2 \Theta 4 bytes pixel \Gamma1 frames of ¸115 Hz for destructive reads and ¸85 Hz for
non­destructive reads (Chapman et al. 1990). Real­time, post­detection image
sharpening via a shift­and­add algorithm keyed on the brightest pixel in a sub­
area, can be driven on the full array at ¸35 Hz. Unfortunately, the IRCAM3
array cannot be driven at these rates (Puxley et al. 1994). Table 1 summa­
rizes the available ALICE/IRCAM3 observing modes. The ALICE/IRCAM3
observing regimes include STARE, ND STARE, CHOP, ND CHOP, and Shift­
and­Add, presented to the observer via Starlink's SMS user interface.
6. Future Plans
The immediate plan is to install and commission the second ALICE as part of the
CGS4 upgrade beginning in 1994 November. The major parts of this program
are modifications to the CGS4 instrument (hardware) to handle the smaller
pixel size in the larger array (30 ¯m as opposed to 76 ¯m), the introduction of

4
Table 1. IRCAM3/ALICE Observing Modes
Observing Mode 80% Well Depth Readout Area Exp min
a M sat
b
(ms) J K L
Standard 80,000 e \Gamma 256 2 120 8.6 7.8 7.4
(JHK) (13,500 DN) 128 2 35 7.3 6.5 6.2
64 2 12.5 6.2 5.4 5.0
Fast 80,000 e \Gamma 256 2 72 8.1 7.3 6.9
(Shift and Add) (13,500 DN) 128 2 20 6.7 5.9 5.5
64 2 6.5 5.5 4.6 4.3
Deep Well 144,000 e \Gamma 256 2 72 7.4 6.6 6.3
(nbL, L', nbM) (24,000 DN) 128 2 20 6.1 5.2 4.9
64 2 6.5 4.8 4.0 3.7
a Minimum exposure time in this mode.
b Saturation magnitude for Expmin (0: 00 3 pixel \Gamma1 )
algorithms into the automated data reduction system to compensate for curved
slits and so forth, and the upgrade of the ALICE software to C. Another ALICE
has been built for use with IRCAM2 on the 4.2 m William Herschel Telescope
on La Palma in the Canary Islands. A second­generation ALICE is being built
at the ROE to drive the mid­infrared imager/spectrometer (Michelle). Given
the modularity of the ALICE design, new components such as faster ADCs or
T9000 TRAMs should easily be accommodated, improving performance by a
factor of ¸10 each.
References
McLean, I. S., Chuter, T. C., McCaughrean, M. J., & Rayner, J. T. 1986, in
Instrumentation in Astronomy VI, Proc. SPIE, Vol. 627, ed. D. L.
Crawford (Bellingham, SPIE), p. 430
Mountain, C. M., Robertson, D. J., Lee, T. J., & Wade, R. 1990, in Instrumen­
tation in Astronomy VII, Proc. SPIE, Vol. 1235, ed. D. L. Crawford
(Bellingham, SPIE), p. 25
Pickup, D. A., Sylvester, J., Paterson, M. J., Puxley, P. J., Beard, S. M., & Laird,
D. C. 1993, in Infrared Detectors and Instrumentation, Proc. SPIE, Vol.
1946, ed. A. M. Fowler (Bellingham, SPIE), p. 558
Kelly, B. D., McNally, B. V., & Stewart, J. M. 1993, in Astronomical Data
Analysis Software and Systems II, ASP Conf. Ser., Vol. 52, eds. R. J.
Hanisch, R. J. V. Brissenden, & J. Barnes (San Francisco, ASP), p. 305

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Chapman, A. R., Beard, S. M., Mountain, C. M., Pettie, D. G., Pickup, D. A.,
& Wade, R. 1990, in Instrumentation in Astronomy VII, Proc. SPIE,
Vol. 1235, ed. D. L. Crawford (Bellingham, SPIE), p. 25
Puxley, P. J., Sylvester, J., Pickup, D. A., Paterson, M. J., Laird, D. C., & Atad,
E. 1994, in Instrumentation in Astronomy VIII, Proc. SPIE, Vol. 2198,
ed. D. L. Crawford (Bellingham, SPIE), p. 350