The NASA Stratospheric Observatory for Infrared Astronomy (SOFIA)
Program has made a programmatic decision to cease the science instrument
development of CASIMIR by the end of December 2010. CASIMIR, Caltech
Airborne Submillimeter Interstellar Medium Investigations Receiver, was a
planned high-resolution heterodyne spectrometer to have operated in five
bands between 500 and 1500 GHz. The decision to withdraw CASIMIR from the
suite of first-generation SOFIA science instruments was motivated by
budget pressures and the science contributions from current and planned
high-resolution submillimeter spectrometers on other facilities. High
resolution spectroscopy remains an important priority for SOFIA, and the
ongoing rapid advancements in technology may make an advanced heterodyne
spectrometer a compelling option in the future.
CASIMIR
| Name of Instrument: |
CASIMIR - CAltech Submillimeter
Interstellar Medium Investigations Receiver |
| Instrument type: |
Heterodyne Spectrometer
250-600 microns |
|
Principal Investigator:
|
J. Zmuidzinas |
Scientific/Technical Abstract:
CASIMIR will be a sensitive submillimeter and far-infrared
heterodyne receiver for SOFIA. The receiver will use sensitive superconducting
mixers, including both tunnel junction (SIS) and hot electron bolometers
(HEB). The double-sideband receiver noise temperatures are projected
to be 4-10 times the quantum limit. The local oscillators will be
continuously tunable, and will consist of Gunn oscillators or HEMT
power amplifiers followed by frequency multipliers.
Our goal is to cover the 500-2100 GHz frequency range
in seven bands: SIS mixers in four bands up to 1200 GHz, and HEB
mixers in three bands covering 1200-2100 GHz. Up to four of these
frequency bands could be selected for use on a given flight; if
necessary, the selection of frequency bands could be changed between
flights. The HEB mixers will not be available at first light on
SOFIA. The receiver will have an intermediate-frequency (IF) bandwidth
of 4 GHz, which will be processed by a high resolution backend spectrometer
(most likely an acousto-optic spectrometer with 1 MHz resolution),
as well as a low resolution (30 MHz) analog correlator.
This instrument will be used to study a wide range of
astrophysical problems ranging from the evolution of galaxies to
the birth and death of stars.
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