Delay Line Readout Research Articles

Position- and time-sensitive single photon detector with delay-line readout

We have developed an image intensifier tube with delay-line anode for time- and position-sensitive detection of single photons. By combining two well-approved techniques, the helical-wire delay-line readout for single particle detection and the production capability for large-format sealed photo-multiplier tubes with microchannel-plates, it is possible to build single photon sensors with 40 and 75 mm diameter. Applications are found wherever precise time tagging (< 1 ns) in combination with high position resolution (1000×1000 pixel) for single photon detection is of equal importance. Due to the low background this technique is especially suited for imaging at very low light intensity or for “3d” imaging and timing applications such as fluorescence microscopy or coincident photon detection experiments. We present the performance of prototype detectors with 75 mm low-noise S-20 and 40 mm S-20 red-enhanced photo-cathodes.

High impedance discrete delay-line readout circuit for silicon strip detector

A prototype 16-tap high impedance discrete delay-line readout circuit has been designed and fabricated for Si-strip detectors suitable for nuclear physics experiments involving moderate count rate applications. The delay-line offers a delay of ∼30 ns per tap with very good linearity. The energy resolution for α-particles from 241Am 239Pu source is found to be satisfactory, when 16 strips are connected through the above readout circuit of a 32-strip Si-strip detector having a dead layer of 5 μm. This readout system is very useful where a large number of detectors are integrated in a compact space and accommodating their readout electronics is a cumbersome task.

Development of advanced x-ray imaging crystal spectrometer utilizing a large area segmented proportional counter for KSTAR

An advanced x-ray imaging crystal spectrometer (XICS) for KSTAR tokamak has been developed by utilizing a segmented two dimensional (2D) position-sensitive multiwire proportional counter. The XICS for the KSTAR tokamak provides time-resolved measurements of the radial ion and electron temperature profiles, toroidal plasma rotation velocity, and ionization equilibrium. The segmented 2D detector with delay-line readout and supporting electronics has been adopted to improve the photon count rate capability. The current fabrication status of the XICS for the KSTAR tokamak and the first performance test results of the prototype segmented 2D detector are presented.

High Resolution Photon Counting Detection System for Advanced Inelastic X-Ray Scattering Studies

High brilliance and high spectral resolution of synchrotron sources and associated optics enable a large number of soft-X-ray spectroscopic studies such as inelastic X-ray scattering, which is becoming a technique of choice for the investigation of the electronic properties of complex materials. The resolution of the detection system in such experiments has to match the accuracy of the probe beam in order to take the full advantage of the performance of modern synchrotron sources. In this paper we describe our advanced photon counting detection system capable of simultaneously registering both position and time of individual photons with 2-dimensional spatial accuracy of < 50 mum and timing accuracy of < 130 ps FWHM. The open face, 25 mm active area detector consists of a Z-stack of microchannel plates and a cross delay line readout and has a dark count rate of only a few counts per second. The associated electronics allows event counting rates up to ~400 KHz with 10% dead time for randomly events. We present the results of our first measurements of delayed fluorescence from different materials performed at the Advanced Light Source. Time and angular resolved fluorescence measurements allowed us to separate images for the prompt elastically scattered and the delayed photons. The detector can also distinguish registration of electrons, ions or photons by variation of the potential on its input mesh. These results demonstrate the capabilities of our detection system, which is currently being integrated into an advanced time resolved X-ray emission spectroscopy system.

A high spatial resolution event counting neutron detector using microchannel plates and cross delay line readout

We have developed and tested a 25 mm aperture event counting two-dimensional imaging detector with high time resolution using neutron-sensitive microchannel plates and a cross delay line readout anode. Spatial resolution of better than 17 μm RMS has been demonstrated along with thermal neutron detection efficiencies of about 20%. Each event can be time tagged to better than 25 ns and event rates in excess of 1 MHz may be achieved.

High spatial resolution neutron sensing microchannel plate detectors

Neutron sensing microchannel plates (MCPs) developed by Nova Scientific Inc. incorporate high-efficiency neutron conversion materials in the MCP glass to provide a high neutron stopping power. We have developed and tested neutron event counting 2D-imaging detectors using these MCPs with three different imaging systems, a cross delay line readout, a cross strip readout, and a MEDIPIX readout. Tests at MNRC and NIST with the cross delay line and cross strip readouts have established spatial resolution with neutrons as good as 17 μm RMS over 27 mm, with event rates of 1 MHz, event time tagging of 25 ns and intrinsic background rates of <0.05 events cm −2 s −1. MEDIPIX readouts for neutron imaging have poorer spatial resolution (55 μm) and event timing, but are capable of even higher rates (GHz).

A self contained Linux based data acquisition system for 2D detectors with delay line readout

This article describes a fast and self-contained data acquisition system for 2D gas-filled detectors with delay line readout. It allows the realization of time resolved experiments in the millisecond scale. The acquisition system comprises of an industrial PC running Linux, a commercial time-to-digital converter and an in-house developed histogramming PCI card. The PC provides a mass storage for images and a graphical user interface for system monitoring and control. The histogramming card builds images with a maximum count rate of 5 MHz limited by the time-to-digital converter. Histograms are transferred to the PC at 85 MB/s. This card also includes a time frame generator, a calibration channel unit and eight digital outputs for experiment control. The control software was developed for easy integration into a beamline, including scans. The system is fully operational at the Spanish beamline BM16 at the ESRF in France, the neutron beamlines Adam and Eva at the ILL in France, the Max Plank Institute in Stuttgart in Germany, the University of Copenhagen in Denmark and at the future ALBA synchrotron in Spain. Some representative collected images from synchrotron and neutron beamlines are presented.

Alice: The rosetta Ultraviolet Imaging Spectrograph

We describe the design, performance and scientific objectives of the NASA-funded ALICE instrument aboard the ESA Rosetta asteroid flyby/comet rendezvous mission. ALICE is a lightweight, low-power, and low-cost imaging spectrograph optimized for cometary far-ultraviolet (FUV) spectroscopy. It will be the first UV spectrograph to study a comet at close range. It is designed to obtain spatially-resolved spectra of Rosetta mission targets in the 700–2050 A spectral band with a spectral resolution between 8 A and 12 A for extended sources that fill its ∼0.05^ × 6.0^ field-of-view. ALICE employs an off-axis telescope feeding a 0.15-m normal incidence Rowland circle spectrograph with a toroidal concave holographic reflection grating. The microchannel plate detector utilizes dual solar-blind opaque photocathodes (KBr and CsI) and employs a two-dimensional delay-line readout array. The instrument is controlled by an internal microprocessor. During the prime Rosetta mission, ALICE will characterize comet 67P/Churyumov-Gerasimenko's coma, its nucleus, and nucleus/coma coupling; during cruise to the comet, ALICE will make observations of the mission's two asteroid flyby targets and of Mars, its moons, and of Earth's moon. ALICE has already successfully completed the in-flight commissioning phase and is operating well in flight. It has been characterized in flight with stellar flux calibrations, observations of the Moon during the first Earth fly-by, and observations of comet C/2002 T7 (LINEAR) in 2004 and comet 9P/Tempel 1 during the 2005 Deep Impact comet-collision observing campaign.

Software modules of DAQ PCI board (DeLiDAQ) for positive-sensitive MWPC detectors with delay line readout

The data acquisition system for the position-sensitive delay line detectors on basis of the reprogrammable PCI DAQ board (DeLiDAQ) began to be used for scientific measurements with one- and two-dimensional position-sensitive MWPC detectors on the neutron reactors IBR-2 (JINR, Dubna) and BERII (HMI, Berlin). A stand-alone version of the system with the graphical user interface on the basis of packet ROOT can be used on any PC with the operating system Windows 2000 or Windows XP. Architecture of the created software ensures several ways of interfacing to experiment control systems. In the paper we provide a description of the DeLiDAQ software modules, their features and results of some performance tests.

A wide-angle magnetic spectrograph of a novel design

At the 5MV tandem accelerator of the CMAM we install a UHV magnetic spectrograph for the detection of scattered and recoiled ions. Its special feature is that the ions emerging from the sample are passing through a 4nm thick DLC foil before entering the spectrograph. The secondary electrons emerging from this foil upon passage of an ion are focused on a two-dimensional position sensitive multi-channel plate (MCP) detector with delay-line read-out. From their impact position on this detector the direction of the ion is determined with a precision of 0.15° within an elliptical cone of 6°×9°. The spectrograph, consisting of a 115° sector magnet with special shaped pole faces, focuses the ions onto a one-dimensional position sensitive MCP detector, also with delay-line read-out, in the focal plane of the magnet. The time delay of the coincident pulses in the first and second detector is measured so that the velocity v of the ion is known in addition to the magnetic rigidity mv/q, allowing determination of m/q. The energy resolution is determined by the straggling in the foil and amounts to ΔE/E≈10−3 for 2MeV α particles. Blocking patterns of scattered or recoiled ions can be measured in one run. Because of the ion identification implied in the system, recoil spectra can be generated with light ions used as projectile.

Improving MWPC delay line readout by waveform analysis

A readout method based on fast waveform digitalization is proposed which improves the performance of large multiwire proportional chambers (MWPCs) with delay-line readout. Atmospheric muon detection data are presented, obtained with a 1 mtimes1 m, 200 wire, MWPC and two plastic scintillators, having the same sensitive area, used for muon identification purposes. The performance of two alternative data acquisition configurations is compared: the standard one, based on analog constant fraction discriminators (CFDs), and one using 5 GS/s waveform digitizers in which a CFD-like analysis is performed offline. The latter is shown to provide better, and more uniform, space resolution, allowing to correct position-dependent rise-time variations across the detector. The new technique is applicable to low count-rate applications, such as muon attenuation measurements in large matter volumes

The On-Orbit Performance of the Galaxy Evolution Explorer

We report the first year on-orbit performance results for the Galaxy Evolution Explorer (GALEX), a NASA Small Explorer that is performing a survey of the sky in two ultraviolet bands. The instrument comprises a 50 cm diameter modified Ritchey-Chretien telescope with a 1.25 degree field of view, selectable imaging and objective grism spectroscopic modes, and an innovative optical system with a thin-film multilayer dichroic beam splitter that enables simultaneous imaging by a pair of photon counting, microchannel plate, delay line readout detectors. Initial measurements demonstrate that GALEX is performing well, meeting its requirements for resolution, efficiency, astrometry, bandpass definition and survey sensitivity.

Fast and compact data acquisition for gas-filled detectors with delay line

This article describes the functionality, implementation and performance of a PCI data acquisition board that can be used in conjunction with gas-filled detectors with delay line readout. The board combines a large on-board 256-MByte histogramming memory with a maximum 10-MHz count rate in continuous operation and integrates the time frame generation, histogram building and buffering functionalities in a single PCI board, resulting in a fast, compact and cost-effective data acquisition solution for the Spanish beamline BM16 at ESRF.

2D-MWPC for the new reflectometer REFSANS/FRM-II: performance of the prototype

A multi-wire proportional counter with delay line readout, a sensitive area of 500×500 mm 2 and a spatial resolution of ∼2×2 mm 2 is being developed for the reflectometer REFSANS at the new reactor FRM-II in Munich in Germany. The characterization of a prototype of this detector with γ-rays and neutrons is presented.

A versatile data acquisition system for time resolved X-ray scattering using gas proportional detectors with delay line readout

A data acquisition system for time resolved X-ray scattering experiments using linear, quadrant or area gas proportional detectors with delay line readout based on commercially available hardware (National Instruments) is described. The system can easily be configured for recording data from point detectors (e.g. photomultipliers and photodiodes) and/or ancillary data only. Applications involving measurements with two different types of time to digital converters illustrate the features and performances of the system.

Development of hybrid low-pressure MSGC neutron detectors

For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and <10 ns FWHM for thermal neutrons, respectively, the latter limited by the transit time through the converter. In the European R&D project TECHNI for this detector an advanced delay line readout technology with multi-event readout was developed as an economical solution for the majority of applications, which, however, limits the position resolution and rate capability to <0.3 mm and 1–2 Mcps, respectively. Therefore, in the successor project DETNI a dedicated ASIC family is being developed for achieving position resolutions of ∼100 μm FWHM and counting rates of ∼10 8 cps. This will open up novel applications based on time-of-flight (TOF) and single-event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography/tomography, TOF Laue diffraction, single crystal diffraction and focusing low- Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier results.

Two-dimensional GEM imaging detector with delay-line readout

A 100×100 mm 2 2D imaging detector, based on a triple-GEM gaseous multiplier, striped x− y readout anode and discrete delay-line readout, is presented. The fast (2.1 ns tap −1) delay-line circuit was designed to match the anode-charge signal profile, namely its rise-time and length. The detector's imaging capability was systematically studied in Ar/CO 2 (70/30) with 5.9 keV X-rays; x− y resolution of σ=0.05 and 0.1 mm for top and bottom anode strips, respectively, and integral non-linearity of ∼0.15% are demonstrated.

Analysis of fluorescence effects in a position-sensitive gas detector using a time-stamp time-to-digital converter

A position-sensitive gas proportional detector with delay line readout was used with the prototype of a time-stamp time-to-digital converter (TS-TDC). The distribution of simultaneous events in the detector upon irradiation by a 55Fe source and synchrotron radiation was analysed as well as the influence of fluorescence on the point-spread function. It is shown that the additional information obtained with the TS-TDC can be used to reduce the distortions caused by fluorescence.

High-resolution and high-intensity neutron diffractometer with linear position-sensitive detector

The characteristics of a neutron diffractometer using a 3 He one-dimensional position-sensitive detector (PSD) with delay line readout, a 200 (length) × 100 (height) mm 2 active window and 2.5 mm spatial resolution have been studied and compared with those of the High-Resolution Powder Diffractometer (HRPD) of KAERI with 32 3 He conventional tube (∅50 mm) detectors and Soller collimators (10′) before detectors. For the sample to PSD distance R=1200 mm , the PSD subtends 8° angle of 2 θ and provides the resolution and the peak-to-background ratio close to that for HRPD. Time for scanning (with the same statistics) of a 0–160° interval is about 1.6 times longer and the multi-PSD system providing efficiency about 10 times higher than HRPD is proposed. Because of the small angle subtended by the PSD, the parasitic peaks from the sample environment are eliminated and operation without an oscillating radial collimator is possible. Additionally, the proposed diffractometer has an advantage for small samples.

Two-dimensional position-sensitive gaseous detectors for high-resolution neutron and X-ray diffraction

Two-dimensional position-sensitive gaseous detectors have been developed at the Geesthacht Neutron Facility (GeNF) for high-resolution neutron and X-ray diffractometry. They are multi-wire proportional counters with delay-line readout and sensitive areas of 300 mm×300 mm or 500 mm×500 mm. For detecting X-rays, neutrons and hard X-rays the counters are filled with Ar/CO2, 3He/CF4 and Xe/CO2, respectively. One neutron detector is used at the ARES diffractometer at GKSS, which is dedicated to the analysis of residual stresses. Further ones are used for analysing textures and residual stresses at the hard-X-ray beamline PETRA-2 at HASYLAB, and one detector is being developed for the neutron reflectometer REFSANS at the research reactor FRM-II in Munich, Germany.