R. Engels

Forschungszentrum Jülich · Zentralinstitut für Elektronik (ZEL)

High Current Accelerator driven Neutron Sources (HiCANS) are a cost-efficient alternative for future large scale neutron facilities. They excel in transforming neutrons released by the primary nuclear reaction into a spectral range usable for applications. In particular, the cost of a target station represents only a minor fraction of the overall c...

Small-K Advanced DIffractometer (SKADI is a Small-Angle Neutron Scattering (SANS) instrument to be constructed at the European Spallation Source (ESS). SANS instruments allow investigations of the structure of materials in the size regime between Angstroms up to micrometers. As very versatile instruments, they usually cater to the scientific needs...

The response of a position-sensitive Li-glass scintillator detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using collimated beams of thermal neutrons. The detector was moved perpendicularly through the neutron beams in 0.5 to 1.0 mm horizontal and vertical steps. Scintillation was detected...

The response of a position-sensitive Li-glass based scintillation detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using focused beams of 2.5 MeV protons and deuterons. The beams were scanned across the detector in 0.5 mm horizontal and vertical steps perpendicular to the beams. Scintillatio...

The response of a position-sensitive Li-glass scintillator detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using collimated beams of thermal neutrons. The detector was moved perpendicularly through the neutron beams in 0.5 to 1.0 mm horizontal and vertical steps. Scintillation was detected...

The response of a position-sensitive Li-glass based scintillation detector to focused beams of 2.5 MeV protons and deuterons has been investigated. The beams were scanned across the detector in 0.5 mm horizontal and vertical steps perpendicular to the beams. Scintillation light was registered using an 8 by 8 pixel multi-anode photomultiplier tube....

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of theEuropean Spallation Source (ESS), and being made available to the neutron user community. The ESS neutronsource consists of a high-power accelerator and target station, providing a unique long-pulse time structureof slow neutrons. The design cons...

The response of a position-sensitive Li-glass scintillator detector to α-particles from a collimated ²⁴¹ Am source scanned across the face of the detector has been measured. Scintillation light was read out by an 8 × 8 pixel multi-anode photomultiplier and the signal amplitude for each pixel has been recorded for every position on a scan. The pixel...

The response of a position-sensitive Li-glass scintillator detector to alpha-particles from a collimated 241Am source scanned across the face of the detector has been measured. Scintillation light was read out by an 8 X 8 pixel multi-anode photomultiplier and the signal amplitude for each pixel has been recorded for every position on a scan. The pi...

A new detection system based on an array of ³He tubes and innovative fast detection electronics has been installed on the high-intensity small-angle neutron scattering (SANS) diffractometer KWS-2 operated by the Jülich Centre for Neutron Science (JCNS) at the Heinz Meier-Leibnitz Zentrum in Garching, Germany. The new detection system is composed of...

This are the cumulated reports of the SoNDe detector Project as of July 2017. The contained reports are: - Report on the 1x1 module technical demonstrator - Report on used materials - Report on radiation hardness of components - Report on potential additional applications - Report on the 2x2 module technical demonstrator - Report on test results of...

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10⁻⁴ and 0.5 Å⁻¹ by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper)...

Following demand from the user community regarding the possibility of improving the experimental resolution, the dedicated high-intensity/extended Q-range SANS diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center in Garching was equipped with a double-disc chopper with a variable opening slit window and t...

The KWS-1 small-angle neutron scattering (SANS) instrument operated by the Jülich Centre for Neutron Science (JCNS) at the research reactor FRM II of the Heinz Maier-Leibnitz Zentrum in Garching near Munich has been recently upgraded. The KWS-1 instrument was updated, from its active collimation apertures to the detector cabling. Most of the parts...

Radioactive waste has to undergo a process of quality checking in order to check its conformance with national regulations prior to its transport, intermediate storage and final disposal. Within the quality checking of radioactive waste packages non-destructive assays are required to characterize their radio-toxic and chemo-toxic contents. The Inst...

A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic...

The Group for the development of neutron and gamma detectors in the Central Institute of Engineering, Electronics and Analytics (ZEA-2) at Forschungszentrum J\"ulich (FZJ) is developing a fast Anger Camera prototype for improving the rejection of the gamma contamination during the detection of neutrons. The prototype is based on a scintillating pla...

The software package ANTS (Anger-camera type Neutron detector: Toolkit for Simulations), developed for simulation of Anger-type gaseous detectors for thermal neutron imaging was extended to include a module for experimental data processing. Data recorded with a sensor array containing up to 100 photomultiplier tubes (PMT) or silicon photomultiplier...

The Group for the development of neutron and gamma detectors in the Central Institute of Engineering, Electronics and Analytics (ZEA-2) at Forschungszentrum Juelich (FZJ) has developed, in collaboration with European institutes, an Anger Camera prototype for improving the impact point reconstruction of neutron tracks. The detector is a chamber fill...

ESS server PDF download link http://eval.esss.lu.se/DocDB/0002/000274/014/TDR_online_ver_all.pdf ESS, the European Spallation Source, will be a major user facility at which researchers from academia and industry will investigate scientific questions using neutron beams. Neutron methods provide insights about the molecular building blocks of matter...

A 2D position sensitive gas scintillation detector for thermal neutrons is under development as part of the European FP7 NMI3 JRA program (Project 226507). The aim of the project is to have a detector with: sub-millimetre position resolution, high rate capability (>1 MHz), high efficiency (>50% for 1 Angstrom neutrons) and an active area of 200×200...

A gas scintillation Anger camera for thermal neutron imaging is being developed in the frame of the NMI3 FP7 Project 226507 collaboration. The detection medium is a high pressure gas mixture of 3He and CF4. An array of photomultiplier tubes (PMTs) registers photons of the CF4the PMTs. Several secondary scintillation generated in the electron avalan...

A new neutron scintillator based on a 0.1 mm thick 6Li metal sheet close to a thin phosphor LJ-440 was investigated. The phosphorous film consists of an optically transparent 0.25 mm thin polyester film, which on one side is deposited by Ag activated ZnS, with a layer thickness of 3.25mg cm-2. The function and properties of this new scintillator ty...

The detector group of the Central Institute of Electronics at the Forschungszentrum Jülich GmbH was founded in 1968. First developments aimed at a detector system with a position-sensitive BF3 proportional counter for small-angle neutron scattering, which was later used at a beamline of the research reactor FRJ2. At the end of the 1970s first measu...

A high intensity triple-axis spectrometer is described, which has been commissioned only a year before the final shut-down of the FRJ-2 reactor in May 2006. It was designed both as an instrument for quasielastic scattering with polarisation analysis on an area detector, and as a triple-axis spectrometer with polarization analysis for measurements o...

At the small angle neutron scattering instrument KWS2 of the new research reactor FRM II at Munich an upgrade of the detector system is currently under development. In order to improve the count rate capability, the readout electronics of the large scintillation detector is to be replaced by a modern state-of-the-art electronics, which implements a...

In this detector research and development the key product is a 100 mum thin ⁶Li metal foil, which is to be used as converter for neutron detection. Due to the chemical reactivity of metallic lithium a special treatment is required for fabrication of such foils. Preparation by rolling lithium in a glove box, protection with ultra thin pol...

Neutron radiation is a highly penetrating probe, routinely used for non-destructive testing of engineering components and for analysis of the structure and dynamics of novel advanced materials. The same analytical techniques can be employed for characterising objects of art, museum pieces and archaeological findings. In particular, neutron radiogra...

The ICC neutron detector is an ionization chamber with three neutron absorbing converter electrodes of ⁶Li metal foils. On both sides the foils face collector electrodes that are positively biased. The neutron detection was investigated at the pulsed neutron source of the Argonne National Laboratory, Argonne, IL. The induced charge due t...

During an electron beam evaporation accidentally sintered boron nitride was discovered to be a bright scintillating material. The high density boron nitride HDBN of Henze showed most promising results concerning light emission due to 8 keV electron radiation, due to bombardment with 5 MeV alpha particles, and due to 240 nm UV radiation. The light p...

Contemporary projects such as AUGER in Argentina or HESS in Namibia are rather expensive experiments. We have constructed a simple detector arrangement based on the water Cherenkov technique to be used for the detection of high-energy particles in cosmic ray experiments either as stand-alone experiment or as addition to other set-ups. A first proto...

The ICC neutron detector is an ionisation chamber with three neutron absorbing converter electrodes of ⁶Li metal foils. On both sides the foils face collector electrodes that are positively biased. The neutron detection was investigated at the pulsed neutron source of the Argonne National Laboratory. The induced charge due to drifting el...

The detection of neutrons with thin ⁶Li containing films or layers within an ionization chamber is discussed. A detection efficiency of 50% for thermal neutrons is obtainable with three 100-μm thin ⁶Li foils. Preliminary measurements were performed with converters which contain a 1-μm thin ⁶LiF layer. The detector e...

During the upgrade of the small-angle neutron scattering instrument KWS-1 at the research reactor FRJ-2, the 15-yr-old detector system has been replaced. While the Anger camera-based concept of the detector remained unchanged, the signal and data processing branch has been completely revised. Because of higher count rate requirements, a highly conf...

The Central Electronics institut (ZEL) is a scientific-technical joint facility of the Research Centre Jülich. In the framework of the detectorelectronics development, a new, full digital readout electronic for two-dimensional neutron detectors was developed. The compactPCI based system, integrates our own fast, digital FPGA and DSP hardware with N...

During the upgrade of the small angle neutron scattering instrument KWS-1 at the research reactor FPJ-2, the 15 years old detector system has been replaced. While the Anger camera based concept of the detector remained unchanged the signal and data processing branch has been completely revised. Because of higher count rate requirements, a highly co...

The Flat-Panel photomultiplier (Hamamatsu H8500) can be utilized as a high resolution area detector for thermal neutrons and high energy gamma rays. This detector type is useful for special neutron scattering experiments and for the PET applied to small animals. In various test measurements this will be demonstrated by coupling suitable scintillato...

The detection of neutrons with thin ⁶Li containing films or layers within an ionisation chamber is discussed. A detection efficiency of 50% for thermal neutrons is obtainable with three 100μm thin ⁶Li foils. Preliminary measurements were performed with converters which contain a 1μm thin ⁶LiF layer. The detector eff...

The invention relates to an evaluation unit to evaluate detector events registered by one or more detectors, whereby the evaluation unit contains signal processors that serve to process the signals from the detectors. According to the invention, the evaluation unit is characterized in that it has at least one distributor that relays the signals fro...

A simple neutron counter based on a scintillator strip, a wavelength shifter rod, and a photomultiplier was constructed in order to compare the properties of such a detector to a commercially available ³He counter. A calculation of the number of photons per absorbed neutron showed that with the bright ⁶Li¹⁵⁸Gd(<sup>...

For high resolution positron emission tomographs based on scintillation detectors a fast, dense and bright scintillator is required. An early sample of a new scintillator, Lu_0.8Y_0.2AlO₃:Ce (LuYAP) with a density of 7.7g/cm³ and a scintillation decay time of 20 ns and 160 ns is compared with LSO and BGO cr...

The performance of scintillation detectors with the advanced scintillator material ⁶Li ¹⁵⁸Gd (¹¹BO₃)₃ was compared with conventional ³He proportional counters at the IPNS spallation source at the Argonne National Laboratory, Argonne, IL. The complex neutron and gamma flux was measure...

The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw...

For two-dimensional scintillation detectors based on position-sensitive photomultipliers, a new PCI or cPCI unit has been developed. It aims at fast signal and data processing by the usage of advanced technologies like digital signal processors and field-programmable gate arrays. The main features of this design are described in this paper. Digital...

A new two-dimensional position-sensitive detector system for small-angle neutron scattering experiments is under development. It is based on a 60×60 cm² large ⁶Li-glass scintillator for the neutron capture and dispersion of the emitted light on an array of photomultiplier tubes for the derivation of the event position. For sub...

A two-dimensional detector system for high-resolution thyroid I-131 scintigraphy was developed. It has a sensitive area of 4×4 cm² and consists of a lead collimator and an array of 10×10 BGO crystals combined with a position-sensitive photomultiplier. The spatial resolution and the sensitivity of the detector have been measured and compa...

This version is available at the following Publisher URL: http://ieeexplore.ieee.org/Xplore/dynhome.jsp

Pulse height division is generally used to determine a position channel for storing detection events in position-sensitive detectors (PSDs). An alternative method based on the maximum likelihood principle is discussed. This principle is modified in order that the storage of events can be done online. Analytic expressions for the spatial resolution...

Single crystals of ⁶Li¹⁵⁸Gd(¹¹B ₃O)₃ were grown, then powdered and mixed with powdered Schott glass and epoxy. The dough was solidified in a Teflon mold to a scintillator foil of 3 mm thickness and size 50 mm×50 mm. By attaching the ⁶Li borate foil to a conventional RCA photo multipl...

During a I-131 therapy of benign and malignant thyroid diseases, precise information about tracer distribution is helpful for patient management. However, the use of established Anger technique for I-131 scintigraphy is difficult because of septal penetration inside the collimator. The aim of this study is to develop a two-dimensional I-131 detecto...

A new two-dimensional position sensitive detector system for small angle neutron scattering experiments is under development. It is based on a 60×60 cm² large ⁶Li-glass scintillator for the neutron capture and a dispersion of the emitted light on an array of photomultiplier tubes for the derivation of the event position. For s...

This version is available at the following Publisher URL: http://ieeexplore.ieee.org/Xplore/dynhome.jsp

For two-dimensional scintillation detectors based on position-sensitive photomultipliers a new PCI or cPCI unit has been developed. It aims at a fast signal and data processing by use of advanced technologies such as digital signal processors and field programmable gate arrays. The main features of this design are described. Digital test measuremen...

The multi-channel photomultiplier (Philips XP1702) can be utilized as a high resolution area detector for thermal neutrons and high energy gamma rays. This detector type is needed, e.g. for special neutron scattering experiments and for the PET method applied to small animals. In various test measurements this will be demonstrated by coupling suita...

The TierPET system, a high resolution 3D positron emission tomograph, has been developed to perform small animal positron emission tomography (PET) studies. High resolution PET opens the possibility to perform animal trials without the need for vivisection. This reduces the number of animals and the costs for such experiments, for example concernin...

During I-131 therapy of benign and malignant thyroid diseases, precise information about tracer distribution is helpful for patient management. However, the established Anger technique is used I-131 scintigraphy is difficult because of septal penetration inside the collimator. The aim of this study is to develop a 2D I-131 detector with high spatia...

The spectrum of position sensitive neutron scintillation detectors, which have been developed and designed in our institute during the last decade, comprises several high resolution linear detectors. The design of the small size high resolution detector is based on a modified Anger technology using a linear array of 24 HAMAMATSU type R1770 rectangu...

In this paper a PCI Initiator/Target Interface is introduced, where a single chip design (XILINX XC4010E) is used to implement a PCI Local Bus Interface, revision 2.1, protocol and timing compliance. The flexible design can be easily adapted for specific interface requirements. This interface card was used for some physical applications, reading da...

We report on the fabrication and characterization of a microstrip X-ray detector with a very high dynamic range based on GaAs diodes. The detector material was grown by liquid phase epitaxy (LPE) and showed a typical n-type background doping of 2×10¹³ cm^-3. The thickness of the epitaxial layer was between 75 and 200 μm. At 27...

The TierPET system, a high resolution 3D positron emission tomograph, has been developed to perform small animal positron emission tomography (PET) studies. High resolution PET opens the possibility to perform animal trials without the need for vivisection. This reduces the expense for such experiments, saving animal lives and cutting costs for exa...

The multi-channel photomultiplier (Philips XP1702) can be utilized as a high resolution area detector for thermal neutrons and high energy gamma rays. This detector type is needed e.g. for special neutron scattering experiments and for the PET method applied to small animals. In various test measurements this will be demonstrated by coupling suitab...

We report on the fabrication and characterization of a microstrip X-ray detector with a very high dynamic range based on GaAs diodes. The detector material was grown by Liquid Phase Epitaxy (LPE) and showed a typical n-type background doping of 2×10¹³ cm^-3. The thickness of the epitaxial layer was between 75 and 200 μm. At 27...

We report on the fabrication and characterization of GaAs based X-ray detectors. The detector structures are grown by liquid phase epitaxy (LPE) and show typical background doping in the order of 10¹⁴ cm^-3 (n-type) so that active regions up to 43 μm could be realized. Schottky diodes were processed with active areas up to 1 mm...

The energy sensitivity of a two-dimensional scintillation gamma detector based on position sensitive photomultipliers has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by ±50%, a discrimination unit has been developed of which the digital upper and lower discrimination levels are...

The enormous progress in silicon semiconductor technology allows one to construct one- and two-dimensional position-sensitive detectors for neutrons with large area Si diodes and thin 6LiF converter layers. Such detectors promise to have extreme low gamma sensitivity, a spatial resolution in the wide range from 10 to 0.1 mm, and operate in varying...

The detection of thermal neutrons absorbed by a thin layer of 6LiF in front of a p− n n+ Silicon diode has been demonstrated. With such a layer attached to a strip diode a linear position-sensitive neutron detector is presented. A spatial resolution of 1.25 mm was measured, and it is equal to the pitch of the 24 metal strips on the 30 mm × 30 mm di...