Objective
The main objective is the definition and the construction of a sensitive microwave heterodyne receiver in order to measure very faint spectral lines of various minor constituents of the stratosphere from the ground. This instrument will be operated in a broad bandwidth of more than 10 GHz which is included within the frequency range 190 to 300 GHz. In this range, there exist many lines of various molecules of interest to study the chemical composition of the stratosphere such as ClO, ClONO2, HNO3, HO2, NO2, N2O and eventually O3.
At the end of the contract, the objective is to use the new prototype as a stable instrument located in a site at a height altitude which is needed due to the frequency range of the instrument. In addition, a farther objective is that this radiometer serves as the prototype of an instrument to be constructed in several units by european industrial firms. Such instruments could then be located in the primary stations of the Network for the Detection of Stratospheric Change (NDSC), which is a network of observation of the stratosphere.
The principle design of the instrument able to measure ClO and other relevant trace species is a heterodyne
receiver with a 10 to 20 GHz instantaneous bandwidth, tuneable within an as broad as possible frequency range,
included in the domain 190 to 300 GHz, measures the thermal emission of very weak spectral lines with
brightness temperatures lower than 100 mK, which has to be down converted to a suitable intermediate
frequency (IF) where further amplification by low noise amplifiers is possible.
The system can be divided into five functional parts which are more or less independent:
- a beam pointing system, external calibration, SSB filtering with some of the quasi-optics,
- a cooled receiver including the rest of the quasi-optics, the cold loads, the mixer, the cooled preamplifier, all
components being located in a cryostat cooled to 4 K,
- a local oscillator (LO) complete system with oscillator, multiplier, phase-lock loops and eventually a levelling
loop.
- the back-end, consisting of IF post-amplifier chain, converters and filters for the corresponding bandwidths
(B/W) of the spectrometers with acquisition/control electronics. - the interface computer-instrument with its control and data acquisition software.
Innovation and a high degree of technical capabilities is therefore required and obtained in different areas such
as:
- Development of very low-noise mixers en the millimetre-wave range in SIS technology,
- Design of cooled HEMT amplifiers,
- Development and manufacturing of reliable cryogenic cooling systems, - Improvement in quasi-optics design.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- natural sciencescomputer and information sciencessoftware
- natural sciencesearth and related environmental sciencesatmospheric sciences
- engineering and technologymechanical engineeringthermodynamic engineering
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Topic(s)
Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
33270 Floirac
France