Focal plane cameras for ESA optical astronomy missions Lumb, D.H.; Rando, N.; Peacock, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2003, Letnik:
513, Številka:
1
Journal Article
Recenzirano
Charge-coupled devices (CCDs) have played an important role in imaging and spectroscopic measurements for visible wavelength astronomy. Their introduction has been largely responsible for driving the ...deployment of 8–10
m class telescopes, and in consequence have revolutionized experimental cosmology. Other scientific initiatives such as planet-finding are rapidly increasing in importance for the astronomical community, and we review two future European Space Agency missions which emphasize such new directions. In each case, we address some detailed design issues for their focal planes, showing how new CCD development activities may satisfy the mission requirements.
STJ observations of the eclipsing polar HU Aqr Bridge, C. M.; Cropper, Mark; Ramsay, Gavin ...
Monthly notices of the Royal Astronomical Society,
11/2002, Letnik:
336, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Abstract
We apply an eclipse mapping technique to observations of the eclipsing magnetic cataclysmic variable HU Aqr. The observations were made with the S-Cam2 superconducting tunnel junction ...detector at the William Herschel Telescope in 2000 October, providing high signal-to-noise ratio observations with simultaneous spectral and temporal resolution. HU Aqr was in a bright (high accretion) state (V= 14.7) and the stream contributes as much to the overall system brightness as the accretion region on the white dwarf. The stream is modelled assuming accretion is occurring on to only one pole of the white dwarf. We find enhanced brightness towards the accretion region from irradiation and interpret enhanced brightness in the threading region, where the ballistic stream is redirected to follow the magnetic field lines of the white dwarf, as magnetic heating from the stream-field interaction, which is consistent with recent theoretical results. Changes in the stream eclipse profile over one orbital period indicate that the magnetic heating process is unstable.
Due to the slowness of the electron–phonon interaction in small gap STJs currently being developed as the latest generation of photon detectors, during the device operation a broad statistical ...distribution of interacting quasiparticles and phonons is established. This gives rise to new physical phenomena and also renders the traditional Rothwarf–Taylor model completely inadequate for the analysis of quasiparticle and phonon dynamics for all traditional superconductors except unproximised Nb. We have developed a new kinetic approach replacing the Rothwarf–Taylor scheme. We demonstrate the results of experimental and theoretical studies of the new physical phenomenon of quasiparticle self-generation in a heavily proximised multiple tunneling Ta/Al STJ and discuss the implications of the observed quasiparticle self-generation for photon detection.
Photon counting experiments with Ta/Al superconducting tunnel junctions are presented. Single photon detection is demonstrated in the wavelength range /spl lambda/=200-2000 nn with a resolving power .../spl lambda///spl Delta//spl lambda/=22-4. The response of the detector shows good linearity with photon energy.
IR filters for high responsivity cryogenic detectors Rando, N; Verhoeve, P; Gondoin, P ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2000, Letnik:
444, Številka:
1
Journal Article
Recenzirano
Modern cryogenic detectors, such as Superconducting Tunnel Junctions and Transition Edge Sensors, provide single photon counting performance, medium to high energy resolution, high count rates and ...good photon collection efficiency over a wide wavelength range. In order to avoid background limited performance, it is necessary to shield the detectors from any thermal IR radiation originating from the surrounding warm surfaces. In this paper we analyse the contribution of the thermal radiation to the detector performance and describe the IR filters used in the
S-Cam camera and in other experimental configurations. Future detectors may require very severe attenuation of the IR flux (
λ>1
μm). Solutions to this problem are proposed and their validity demonstrated with experimental results.
First astronomical results from S-Cam Rando, N; Andersson, S; Collaudin, B ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2000, Letnik:
444, Številka:
1
Journal Article
Recenzirano
S-Cam is a cryogenic camera for ground-based astronomy based on a 6×6 array of Superconducting Tunnel Junctions (STJs). The camera has been designed as a technology demonstrator, aiming to prove the ...potential of this new generation of single photon counting detectors at a ground-based telescope. In this article we provide an overview of the detector performance, a description of the
S-Cam system and a summary of the test results. The first astronomical data obtained at the William Herschel Telescope (WHT) in La Palma (Canary Islands, Spain) are also described.
We present the first results obtained with a two-dimensional X-ray imaging spectrometer consisting of a 200×200
μm
2 Ta absorber and read out by four Ta/Al superconducting tunnel junctions (STJs). A ...preliminary image reconstruction algorithm allows the visualisation of the diffraction pattern from a 5
μm pinhole illuminated with 10
keV X-rays. The image suggests a spatial resolution better than 10
μm. The algorithm does not take into account quasi-particle losses in the absorber. Hence, the pulse-height reconstruction is not optimal and the energy resolution varies significantly across the absorber. The best energy resolution is obtained for a 20×20
μm
2 area in the centre of the absorber, and amounts to ∼77
eV at a photon energy of 5895
eV, with a 70
eV electronic noise contribution.
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