@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix ns0: <http://gcmd.gsfc.nasa.gov/kms#> .

<https://gcmd.earthdata.nasa.gov/kms/concept/c143ee20-1d14-4003-9043-f028c19f0265>
  skos:changeNote """2018-07-05 14:14:46.0 [mmorahan] Insert Concept 
add broader relation (SMR [c143ee20-1d14-4003-9043-f028c19f0265,367783] - Radiometers [5b753e40-b3f1-426a-8d92-ffee1d675468,347283]); 
""", """2018-07-05 14:16:57.0 [mmorahan]  
insert AltLabel (id: null
category: primary
text: Sub-Millimeter Radiometer
language code: en); 
insert Definition (id: null
text: The Odin SMR (Sub-Millimeter Radiometer) instrument continues to produce profiles of chemical species relevant to understanding the middle and upper atmosphere. The long-term observation of stratospheric ozone can be useful for trend analysis of chemical ozone loss.

SMR is a Swedish instrument in cooperation with Finland (119 GHz channel), and France, provision of the AOS (Acousto-Optic Spectrometer) detector. SMR is a passive microwave limb sounder with one receiver at a wavelength of 3 mm and additional four bands within the submillimeter range (0.5 - 1.0 mm) corresponding to a frequency range of 486 - 580 GHz. Antenna reflector type: offset Gregorian telescope [off-axis system, 1.1 m diameter, surface roughness: 10 µm rms, material: carbon fiber reinforced plastic (CFRP)]. SMR is used in the astronomy as well as in the atmospheric research mission to detect molecular transitions.

The signal coming from the telescope is routed to the receivers, split and filtered by optics consisting of combinations of mirrors, grids and meshes. Diplexers and sideband filters are based on tunable polarizing Michelson interferometers. The SMR telescope is being equipped with a very flexible cryogenic sub-mm receiver package (cooling to -175º C). The frequency range of 541-581 GHz is covered by three tuneable Schottky mixers and a fourth Schottky mixer covers the band 486-504 GHz. A 119 GHz fix-tuned HEMT preamplifier has been installed to allow very sensitive searches for interstellar O2. All receivers are operated in single-sideband mode.

The five single sideband heterodyne receivers in SMR are continuously switched between a reference source of known signal strength and the signal from the telescope (Dicke switch). The telescope is periodically targeted towards well-known celestial objects. These procedures ensure both stability and good calibration.

Spectral lines: The SMR instrument covers transitions of aeronomical interest from the following molecules: ClO, CO, NO2, N2O, H2O2, HO2, H2O, H218O, NO, HNO3, O3, and O2; and atomic and molecular transitions of astrophysical interest from: Cl, H218O, H2O, H2S, NH3, H2CO, O2, CS, 13CO, H2CS, SO, SO2

Type

Single sideband heterodyne receivers (use of InP material),

Frequencies

118.25 - 119.25 GHz, 486.1 - 503.9 GHz, 541 - 580.4 GHz

Bandwidth

100 MHz to 1 GHz

Resolution

0.1 MHz to 1 MHz

Sensitivity

1 K in 1 MHz with S/N = 5 after 15 minutes

Mixers

Cooled Schottky mixers

Local Oscillators

LO based on Gunn diodes and frequency multipliers

LNA

Cooled HEMT low noise amplifiers

Spectrometers

two hybrid autocorrelators and one AOS (Acousto-Optic Spectrometer)
language code: en); 
""", """2019-02-22 08:41:13.0 [mmorahan]  
insert WeightedRelation (id: null
related concept uuid: 1f7c6ae3-d38e-42b7-a874-60298b0fcfa1
relationship type: null
relationship value: null
generated by: null); 
""" ;
  ns0:altLabel [ ] ;
  skos:definition """The Odin SMR (Sub-Millimeter Radiometer) instrument continues to produce profiles of chemical species relevant to understanding the middle and upper atmosphere. The long-term observation of stratospheric ozone can be useful for trend analysis of chemical ozone loss.

SMR is a Swedish instrument in cooperation with Finland (119 GHz channel), and France, provision of the AOS (Acousto-Optic Spectrometer) detector. SMR is a passive microwave limb sounder with one receiver at a wavelength of 3 mm and additional four bands within the submillimeter range (0.5 - 1.0 mm) corresponding to a frequency range of 486 - 580 GHz. Antenna reflector type: offset Gregorian telescope [off-axis system, 1.1 m diameter, surface roughness: 10 µm rms, material: carbon fiber reinforced plastic (CFRP)]. SMR is used in the astronomy as well as in the atmospheric research mission to detect molecular transitions.

The signal coming from the telescope is routed to the receivers, split and filtered by optics consisting of combinations of mirrors, grids and meshes. Diplexers and sideband filters are based on tunable polarizing Michelson interferometers. The SMR telescope is being equipped with a very flexible cryogenic sub-mm receiver package (cooling to -175º C). The frequency range of 541-581 GHz is covered by three tuneable Schottky mixers and a fourth Schottky mixer covers the band 486-504 GHz. A 119 GHz fix-tuned HEMT preamplifier has been installed to allow very sensitive searches for interstellar O2. All receivers are operated in single-sideband mode.

The five single sideband heterodyne receivers in SMR are continuously switched between a reference source of known signal strength and the signal from the telescope (Dicke switch). The telescope is periodically targeted towards well-known celestial objects. These procedures ensure both stability and good calibration.

Spectral lines: The SMR instrument covers transitions of aeronomical interest from the following molecules: ClO, CO, NO2, N2O, H2O2, HO2, H2O, H218O, NO, HNO3, O3, and O2; and atomic and molecular transitions of astrophysical interest from: Cl, H218O, H2O, H2S, NH3, H2CO, O2, CS, 13CO, H2CS, SO, SO2

Type

Single sideband heterodyne receivers (use of InP material),

Frequencies

118.25 - 119.25 GHz, 486.1 - 503.9 GHz, 541 - 580.4 GHz

Bandwidth

100 MHz to 1 GHz

Resolution

0.1 MHz to 1 MHz

Sensitivity

1 K in 1 MHz with S/N = 5 after 15 minutes

Mixers

Cooled Schottky mixers

Local Oscillators

LO based on Gunn diodes and frequency multipliers

LNA

Cooled HEMT low noise amplifiers

Spectrometers

two hybrid autocorrelators and one AOS (Acousto-Optic Spectrometer)"""@en ;
  skos:prefLabel "SMR"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/5b753e40-b3f1-426a-8d92-ffee1d675468> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/5b753e40-b3f1-426a-8d92-ffee1d675468>
  skos:prefLabel "Radiometers"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/c143ee20-1d14-4003-9043-f028c19f0265> .

