A. Zehnder

EUVID — a compact, high-resolution imaging detector for the wavelength range 20 ≤ λ ≤ 1200 Å

Abstract The E xtreme UV I maging D etector EUVID consists of a compact “micro-channel-plate-wedge-and-strip anode” imaging system and corresponding data read-out electronics with 32 MB of memory. EUVID is suited for imaging in the wavelength range 20 ≤ λ ≤ 1200 A . The performance of this space-qualified, 2.5 kg detector system was measured in the FUV. We obtained a spatial resolution of about 70 μm over the full detector area of ∼ 7 cm2. Image distortions are small and can easily be corrected for. Detector efficiency depends on the choice of photocathode and ranges between 50% in the FUV up to 90% in the EUV.

EUVID: A compact, high resolution imaging detector for the wavelength range 20-A <= lambda <= 1200-A

Abstract The E xtreme UV I maging D etector EUVID consists of a compact “micro-channel-plate-wedge-and-strip anode” imaging system and corresponding data read-out electronics with 32 MB of memory. EUVID is suited for imaging in the wavelength range 20 ≤ λ ≤ 1200 A . The performance of this space-qualified, 2.5 kg detector system was measured in the FUV. We obtained a spatial resolution of about 70 μm over the full detector area of ∼ 7 cm2. Image distortions are small and can easily be corrected for. Detector efficiency depends on the choice of photocathode and ranges between 50% in the FUV up to 90% in the EUV.

The influence of proximity effect on the quasiparticle collection

Abstract Results from a comparison between current-voltage data measured on Nb/Al/AlO x /Al/Nb tunneling junctions to a proximity effect model proposed by Golubov et al. [J. Low Temp. Phys. 70 (1988) 83] are used to get an estimation of the quasiparticle collection as a function of the Al-film thickness (4 and 120 nm) in X-ray detectors.

Fabrication of Nb and Ta/Al/AlOx/Al/Nb tunneling junction X-ray detectors: a list of problems

Abstract A whole wafer fabrication procedure using selective etching of refractory materials to produce Nb- or Ta/Al/AlO x Al/Nb tunneling X-ray detectors is discussed. Fabrication aspects and preliminary results are presented.

Superconducting strip detectors as position sensitive particle detectors

Abstract The feasibility of using of current-biased superconducting strips for radiation detection is investigated. Narrow Ta strips are exposed to 5.5 MeV α-particle radiation and the rise-time of the induced voltage pulses is measured as function of temperature and bias current. The rise-time of the voltage signal strongly depends on the site on the strip which is hit by the α-particle. In order to determine the spatial resolution of a superconducting strip detector, position-sensitive measurements were performed. The maximum lateral resolution estimated so far is 25μm in a 7μm wide, 340 nm thick and 0.6 mm long Ta-strip.

A Nb/AlOx/Nb trilayer process for the fabrication of X-ray detectors

Abstract A new Nb/AlO x /Nb trilayer process for X-ray detector applications has been developed. The process employs a movable mechanical slit which, after the sputter deposition of the base Nb electrode followed by a thin layer of Al and its oxidation, is shifted to a second position where the Nb counter electrode is deposited. The overlap area of the two electrodes forms the junction are after final patterning by standard photolithography and reactive ion etching. The best junctions so far obtained have, at 4.2 K, typically a quality factor of 42 mV with a Josepshon current density of 1200 A/cm 2 , and a tunneling time τ tun in the range of 50 to 500 ns. We discuss several aspects of this technique in comparison with the selective niobium anodization process (SNAP) and the selective niobium etching process (SNEP).

Investigations onNb/Al-AlO x -Al/Nb proximity tunneling junctions for X-ray detection

A new Nb/Al-AlOx-Al/Nb trilayer process using a movable mechanical slit for junction-detector applications is described. Best junctions have a quality factor of 42 mV with a Josephson current density of 1200 A/cm2 at 4.2 K. The temperature dependence of the sub-gap current in the range of 0.45 to 4.2 K has been measured. Deviations from the thermally activated behavior due to imperfections in the tunneling barrier are observed. We compare our simple method with the usual whole wafer processes and we discuss the influence of proximity effects in these junctions in terms of the models proposed by Golubov et al. and by McMillan.

A high-resolution imaging detector for VUV applications

Abstract The VUV (30–1200A) detector described consists of a compact ‘Micro-Channel-Plate-Wedge-and-Strip anode’ imaging system and of the corresponding data read-out electronics with 32 Mbyte of memory. The performance of this space qualified detector system was measured in the FUV. We obtained a spatial resolution of about 70 μm over the full detector area of ∼7 cm 2 . Image distortions are small and can easily be corrected for. Detector efficiency depends on the choice of photo-cathode and ranges between 50% in the FUV up to 90% in the EUV.

EUVID — a compact, high-resolution imaging detector for the wavelength range

Abstract The E xtreme UV I maging D etector EUVID consists of a compact “micro-channel-plate-wedge-and-strip anode” imaging system and corresponding data read-out electronics with 32 MB of memory. EUVID is suited for imaging in the wavelength range 20 ≤ λ ≤ 1200 A . The performance of this space-qualified, 2.5 kg detector system was measured in the FUV. We obtained a spatial resolution of about 70 μm over the full detector area of ∼ 7 cm2. Image distortions are small and can easily be corrected for. Detector efficiency depends on the choice of photocathode and ranges between 50% in the FUV up to 90% in the EUV.

Growth of superconducting tantalum films by pulsed laser deposition

Abstract Pulsed laser deposition (PLD) was used to grow superconducting Ta-films with critical temperatures close to bulk values (4.5 K) on sapphire substrates. Results are compared with films grown by e-beam evaporation. The PLD method allows the growth of superconducting Ta-films on substrates kept at ambient temperature but film surfaces are plagued by sub-micron particles. On the other hand, e-beam evaporation results in smooth surfaces but requires a substrate temperature of the order of 400 ° C for producing high-quality superconducting films. Critical temperatures, residual resistance ratios, and crystal structure are presented.