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Dive into the research topics where D. J. Goldie is active.

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Featured researches published by D. J. Goldie.


Applied Physics Letters | 1998

High-resolution x-ray spectra measured using tantalum superconducting tunnel junctions

P. Verhoeve; N. Rando; Anthony J. Peacock; A. van Dordrecht; B. G. Taylor; D. J. Goldie

The spectral response of a 100×100 μm2 tantalum based superconducting tunnel junction to 5.9 keV x-ray photons from a 55Fe source has been studied. In full illumination the energy resolution for the Mn Kα line complex is 56 eV, dominated by spatial nonuniformity in the response of the detector. When illuminating selectively a 5–10 μm diam spot in the center of the detector, the energy resolution improves to 22 eV, corresponding to 15.7 eV for the individual Mn Kα1 and Mn Kα2 lines. This exceeds the predicted theoretical energy resolution of 7.3 eV for this type of device by only a factor of ∼2.


IEEE Transactions on Applied Superconductivity | 1997

Superconducting tunnel junctions as photon counting detectors in the infrared to the ultraviolet

P. Verhoeve; N. Rando; A. Peacock; A. van Dordrecht; A. Poelaert; D. J. Goldie

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.


Journal of Applied Physics | 1998

SINGLE PHOTON DETECTION AT VISIBLE AND X-RAY WAVELENGTHS WITH NB-AL SUPERCONDUCTING TUNNEL JUNCTIONS

P. Verhoeve; N. Rando; Anthony J. Peacock; A. van Dordrecht; A. Poelaert; D. J. Goldie; R. Venn

Photon counting experiments at wavelengths ranging from near infrared to x-ray with niobium based superconducting tunnel junctions with aluminum trapping layers are presented. Single photons can be detected up to a wavelength of 1 μm. The response in the ultraviolet to near-infrared region is characterized by a good energy linearity (<2.5%), a capability to handle event rates up to ∼3 kHz, and moderate energy resolving power (E/ΔE≈7 for E=4 eV). The x-ray response at 6 keV is characterized by anomalously high signals compared to the low energy response, a severe energy nonlinearity and a relatively poor energy resolution of ∼140 eV, full width at half maximum.


Physica C-superconductivity and Its Applications | 2002

A tightly coupled dc SQUID with an intermediary transformer

V. Polushkin; E. Gu; D. Glowacka; D. J. Goldie; J. Lumley

Abstract We have developed a dc SQUID in which the input inductance is coupled via an on chip integrated intermediary transformer. The overall coupling factor between the 0.367 μH input coil and 30 pH dc SQUID was as large as 0.77. In order to eliminate transmission line resonances, due to both the increased coupling factor and the larger input inductance, we introduced a microwave double stage low pass filter into the intermediary transformer. No distortions were observed on the V – Φ curve with modulation depth and steepness as large as 125 μV, and 0.6 mV/ Φ 0 respectively. The measured values of the coupled energy resolution of the SQUID were 1.25×10 −31 J/Hz with a room temperature directly coupled preamplifier and about 10 −32 J/Hz (16 h) in a double stage SQUID configuration at a temperature of 4.2 K in the white frequency range. This corresponds to the current noise of ≈0.8 and 0.25 pA/Hz 1/2 respectively. The 3 dB bandwidth of the single stage SQUID with closed feedback loop is more than 2.5 MHz.


SPIE's International Symposium on Optical Science, Engineering, and Instrumentation | 1998

Development of a superconducting tunnel junction camera for ground-based optical astronomy

N. Rando; Anthony J. Peacock; S. Andersson; Bernard Collaudin; P. Gondoin; J. Verveer; P. Verhoeve; D. J. Goldie; R. Hart

The development of an optical camera based on superconducting tunnel junctions has now reached a stage where practical applications in optical or UV astronomy can be considered. A prototype cryogenic camera (named S-Cam) has been developed, based on a high quantum efficiency 6 X 6 detector array of tantalum Josephson junctions, and operating at a temperature of about 0.4 K. This paper describes the general characteristics of the camera, sensitive in the waveband from 350 to 700 nm and designed to be installed in 1998 at the Nasmyth focus of the William Herschel Telescope in La Palma, Spain. In addition to the performance of the overall system, the preliminary detector unit test results will also be presented. The present S-Cam system performance is discussed in view of future versions of the camera. Provided the field coverage of these cameras can be extended through the development of larger format detector arrays and adequate read-out electronics, they have the potential to provide a significant additional tool for optical and UV astronomy in the next century.


Journal of Applied Physics | 1997

ON THE DETECTION OF SINGLE OPTICAL PHOTONS WITH SUPERCONDUCTING TUNNEL JUNCTION

Anthony J. Peacock; P. Verhoeve; N. Rando; A. van Dordrecht; B. G. Taylor; Christian Erd; M. A. C. Perryman; R. Venn; J. Howlett; D. J. Goldie; J. Lumley; M. Wallis

We report the detection of individual optical and ultraviolet photons using a different approach to photon detection based on a superconducting tunnel junction. A 20×20 μm2 junction, employing a 100 nm niobium film and operated at a temperature of ∼0.4 K, has been used to detect individual photons with inherently high quantum efficiency (>45%) over a broad wavelength range (between 200 and 500 nm), yielding high temporal (sub-ms) resolution, spatial resolution determined by the junction size, under conditions of minimal dark current, and in the absence of read noise. The quantum efficiency is limited by surface reflection, and could be improved by the deposition of antireflection coatings. The theoretical wavelength response range continues into the far UV and soft x-ray region, and is presently limited beyond 500 nm largely by the available signal processing electronics. The device intrinsically functions at very high incident photon rates—with count rates of order ∼10 kHz or higher being feasible and ag...


Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 2000

First astronomical results from S-Cam

N. Rando; S. Andersson; Bernard Collaudin; F. Favata; P. Gondoin; Anthony J. Peacock; M. A. C. Perryman; J. Verveer; P. Verhoeve; D. J. Goldie

Abstract 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.


SPIE's 1994 International Symposium on Optics, Imaging, and Instrumentation | 1994

High-resolution x-ray detection at 1.2 K with niobium superconducting tunnel junctions

P. Verhoeve; N. Rando; P. Videler; Anthony J. Peacock; Axel van Dordrecht; D. J. Goldie; J. Lumley; J. Howlett; M. Wallis; R. Venn

X-ray spectra at 6 keV from niobium based superconducting tunnel junctions with highly transmissive tunnel barriers are presented. Signals from the two films can clearly by discriminated by their different temporal and pulse height characteristics. Levels of tunneled charge as high as 2.7 X 106 electrons at 5.9 keV are observed. The best energy resolution obtained at T equals 1.2 K is 53 eV FWHM including electronic noise, for a 50 X 50 micrometers 2 device in a configuration where the x-ray source is collimated to selectively illuminate the center part of the device. Non-linearity is observed which appears dependent on film volume, implying that self recombination may play an important role in these devices. The energy resolution is found to degrade with increasing magnetic field. The spectra from the polycrystalline top film appear significantly degraded if magnetic flux is deliberately trapped in the device.


Journal of Applied Physics | 1999

On the factors governing the energy resolution of Ta-based superconducting tunnel junctions

S. Kraft; P. Verhoeve; Anthony J. Peacock; N. Rando; D. J. Goldie; R. Hart; D. Glowacka; Frank Scholze; Gerhard Ulm

The spectral response of Ta-based superconducting tunnels junctions to monochromatized synchrotron radiation in the photon energy range between 15 eV and 1.7 keV has been investigated with a view to establishing the physical processes contributing to the energy resolution. The resolution over the whole spectral range is only a factor of two or three above the expected intrinsic tunnel limited resolution. Between 15 and 60 eV peak widths of ∼1 eV have been achieved. Spanning over two orders of magnitude in photon energy the high resolution has allowed us to isolate the various intrinsic components contribution to the spectral response and in essence confirm the validity of models describing the photoabsorption and tunnel processes in a superconducting tunnel junction.


IEEE Transactions on Applied Superconductivity | 1999

Soft X-ray performance of superconducting tunnel junction arrays

P. Verhoeve; S. Kraft; N. Rando; A. Peacock; A. van Dordrecht; R. den Hartog; D. J. Goldie; R. Hart; D. Glowacka

A number of 6/spl times/6 element arrays of Ta-based superconducting tunnel junctions have been manufactured for photon counting applications with moderate energy resolution in ground-based optical astronomy. The individual array elements show low leakage, uniform responsivity across the array, good simultaneous Josephson current suppression and minor crosstalk between adjacent pixels. The same arrays have been characterized in the soft X-ray range (E=270-1500 eV). The base electrode response shows good energy resolving power (E//spl Delta/E/spl ap/140). Unwanted spectral features originating from other parts of the detector can be largely eliminated by rise-time filtering. Modifications in the layering are necessary in order to improve the soft X-ray detection efficiency.

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N. Rando

European Space Agency

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A. Peacock

European Space Research and Technology Centre

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A. van Dordrecht

European Space Research and Technology Centre

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D. Martin

European Space Agency

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M. A. C. Perryman

European Space Research and Technology Centre

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