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Performance of the second Deep Inelastic Neutron Scatering spectrometer at the Bariloche electron LINAC

JOURNAL OF INSTRUMENTATION 2013年第08期8卷 P08016-P08016页

作者： Rodriguez Palomino, L. A. Blostein, J. J. Dawidowski, J. Univ Nacl Cuyo Consejo Nacl Invest Cient & Tecn Ctr Atom Bariloche RA-8400 San Carlos De Bariloche Rio Negro Argentina Univ Nacl Cuyo Inst Balseiro RA-8400 San Carlos De Bariloche Rio Negro Argentina Comis Nacl Energia Atom RA-8400 San Carlos De Bariloche Rio Negro Argentina

We report on the new Deep Inelastic Neutron Scattering detector bank recently implemented at the Bariloche electron LINAC. We show the characterization and calibration process carried out, which comprises the determinarion of the detector bank efficiency, and the evaluation of the performance of the filter difference technique. As part of the benchmarking process, polyethylene spectra were measured and analyzed, and the scattering cross sections for carbon and hydrogen were determined in the process. With the addition of this new detector bank to the existing one, we evaluate the combined capacity of the two banks.

关键词： data processing methods Instrumentation for neutron sources Neutron detectors (cold, thermal, fast neutrons) Gaseous detectors

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T3B-an experiment to measure the time structure of hadronic showers

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JOURNAL OF INSTRUMENTATION 2013年第12期8卷 P12001-P12001页

作者： Simon, F. Soldner, C. Weuste, L. Max Planck Inst Phys & Astrophys D-80805 Munich Germany

The goal of the T3B experiment is the measurement of the time structure of hadronic showers with nanosecond precision and high spatial resolution together with the CALICE hadron calorimeter prototypes, with a focus on the use of tungsten as absorber medium. The detector consists of a strip of 15 scintillator cells individually read out by silicon photomultipliers (SiPMs) and fast oscilloscopes with a PC-controlled data acquisition system. The data reconstruction uses an iterative subtraction technique which provides a determination of the arrival time of each photon on the light sensor with sub-nanosecond precision. The calibration is based on single photon-equivalent dark pulses constantly recorded during data taking, automatically eliminating the temperature dependence of the SiPM gain. In addition, a statistical correction for SiPM afterpulsing is demonstrated. To provide the tools for a comparison of T3B data with GEANT4 simulations, a digitization routine, which accounts for the detector response to energy deposits in the detector, has been implemented.

关键词： data processing methods Timing detectors Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, G-APDs, CCDs, EBCCDs, EMCCDs etc) Calorimeters

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Polarimetric spectra analysis for tokamak pitch angle measurements

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JOURNAL OF INSTRUMENTATION 2013年第10期8卷

作者： Ko, J. Chung, J. Lange, A. G. G. de Bock, M. F. M. Natl Fus Res Inst Taejon 305806 South Korea Eindhoven Univ Technol Dept Appl Phys NL-5600 MB Eindhoven Netherlands

Measurements of the internal magnetic field structures using conventional polarimetric approaches are considered extremely challenging in fusion-reactor environments whereas the information on current density profiles is essential to establish steady-state and advance operation scenarios in such reactor-relevant devices. Therefore, on ITER a hybrid system is proposed for the current density measurements that uses both polarimetry and spectral measurements. The spectrum-based approaches have been tested in the Korea Superconducting Tokamak Advanced Research (KSTAR) during the past two plasma campaigns. As such, KSTAR is a test-bed for the proposed ITER hybrid system. Measurements in the plasma core are based on the motional Stark effect (MSE) spectrum of the neutral beam emission. For the edge profiles, the Zeeman effect (ZE) acting on the lithium emission spectrum of the newly installed (2013) Lithium-beam-diagnostic is exploited. The neutral beam emission spectra, complicated by the multi-ion-source beam injection, are successfully fitted making use of the data provided by the Atomic data and Analysis Structure (ADAS) database package. This way pitch angle profiles could be retrieved from the beam emission spectra. With the same spectrometer/CCD hardware as on MSE, but with a different wavelength range and different lines of sight, the first ZE spectrum measurements have been made. The Zeeman splitting comparable to and greater than the instrumental broadening has been routinely detected at high toroidal field operations (similar to 3 Tesla).

关键词： Plasma diagnostics - interferometry, spectroscopy and imaging Polarimeters Polarisation data processing methods

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Improving the spatial resolution of soft X-ray detection using an Electron-Multiplying Charge-Coupled Device

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JOURNAL OF INSTRUMENTATION 2013年第01期8卷 C01046-C01046页

作者： Soman, M. R. Hall, D. J. Tutt, J. H. Murray, N. J. Holland, A. D. Schmitt, T. Raabe, J. Schmitt, B. Open Univ Ctr Elect Imaging E2v Milton Keynes MK7 6AA Bucks England Paul Scherrer Inst CH-5232 Villigen Switzerland

The Super Advanced X-ray Emission Spectrometer (SAXES) is an instrument at the Swiss Light Source designed for Resonant Inelastic X-ray Scattering with an energy resolution (E/Delta E) better than 12000 at 930 eV. Improvements to the instrument have been predicted that could allow the energy resolution to be improved by a factor of two. To achieve this, the spatial resolution of the detector (currently a Charge-Coupled Device, CCD) over which the energy spectrum is dispersed would have to be improved to better than 5 mu m. X-ray photons with energies between a few hundred to a few thousand electron volts primarily interact within the field-free region of back-illuminated CCDs, where each photon forms an electron cloud that diffuses isotropically before reaching the depleted region close to the electrodes. Each photon's electron cloud is likely to be detected as an event with signal split across multiple pixels. Analysing these split events using centroiding techniques allows the photon's interaction position to be determined to a sub-pixel level. PolLux is a soft X-ray microspectroscopy endstation at the Swiss Light Source that can focus 200 eV to 1200 eV X-rays to a spot size of approximately 20 nm. Previous studies using data taken with a linear scan across the centre of a pixel in 3 mu m steps predicted an improved resolution by applying centroiding techniques and using an Electron-Multiplying CCD (EM-CCD). In this study, a full 2D map of the centroiding accuracy in the pixel is presented, formed by rastering in two dimensions across the image plane in single micron steps. The improved spatial resolution from centroiding events in the EM-CCD in all areas of the pixel over the standard CCD is attributed to the improved signal to noise ratio provided by the multiplication register even at high pixel readout speeds (tens of MHz).

关键词： X-ray detectors Spectrometers Solid state detectors data processing methods

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Reflectometric measurement of plasma imaging and applications

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JOURNAL OF INSTRUMENTATION 2012年第1期7卷 C01089-C01089页

作者： Mase, A. Ito, N. Oda, M. Komada, Y. Nagae, D. Zhang, D. Kogi, Y. Tobimatsu, S. Maruyama, T. Shimazu, H. Sakata, E. Sakai, F. Kuwahara, D. Yoshinaga, T. Tokuzawa, T. Nagayama, Y. Kawahata, K. Yamaguchi, S. Tsuji-lio, S. Domier, C. W. Luhmann, N. C., Jr. Park, H. K. Yun, G. Lee, W. Padhi, S. Kim, K. W. Kyushu Univ Art Sci & Technol Ctr Cooperat Res Kasuga Fukuoka 8168580 Japan Kyushu Hitachi Maxell Ltd Fukuoka 8221296 Japan Miyazaki Prefecture Ind Technol Ctr Miyazaki 8800303 Japan Fukuoka Inst Technol Dept Informat Elect Fukuoka 8110295 Japan Kyushu Univ Fac Med Sci Fukuoka 8128582 Japan Sakura Tech Corp Kawasaki Kanagawa 2130012 Japan Tokyo Inst Technol Grad Sch Sci & Engn Tokyo 1528550 Japan Natl Inst Fus Sci Toki Gifu 5095292 Japan Kansai Univ Fac Engn Sci Suita Osaka 5648680 Japan Univ Calif Davis Dept Elect & Comp Engn Davis CA 95616 USA Pohang Univ Sci & Technol Dept Phys Pohang 790784 South Korea Curtin Univ Int Ctr Radio Astron Res Bentley WA 6102 Australia Kyungpook Natl Univ Sch Elect Engn Taegu 702701 South Korea

Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, such as, plasma diagnostics, radio astronomy, alien substance detection, airborne and spaceborne imaging radars called as synthetic aperture radars, living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic tools. In this report we focus on the reflectometric measurements and applications to biological signals (vital signal detection and breast cancer detection) as well as plasma diagnostics, specifically by use of imaging technique and ultra-wideband radar technique.

关键词： data processing methods Image reconstruction in medical imaging Nuclear instruments and methods for hot plasma diagnostics Plasma diagnostics - interferometry, spectroscopy and imaging

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A wavelength-shifting-fibre-based scintillator neutron detector implemented with the median point calculation method

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JOURNAL OF INSTRUMENTATION 2012年第02期7卷 C02003-C02003页

作者： Nakamura, T. Kawasaki, T. Hosoya, T. Toh, K. Ebine, M. Birumachi, A. Sakasai, K. Soyama, K. Katagiri, M. Japan Atom Energy Agcy Mat & Life Sci Div J PARC Ctr Naka Ibaraki 3191195 Japan Ibaraki Univ Coll Engn Hitachi Ibaraki 3160033 Japan Japan Atom Energy Agcy Mech Engn & Elect Sect Nucl Sci Res Inst Naka Ibaraki 3191195 Japan

Median point calculation (MPC) method for scintillator neutron detectors operating in photon-counting mode has been developed. The method was applied to a wavelength-shifting (WLS)-fibre-based neutron detector in order to improve its pixel size and spatial resolution. The original detector was modified for a demonstration experiment performed using the SENJU neutron diffraction instrument at J-PARC (Japan Proton Accelerator Research Complex). The detector head comprised 64 x 2 WLS fibres arranged in the x and y directions at a pitch of 4 mm. The WLS fibres were sandwiched between two ZnS/(B2O3)-B-10 scintillator screens. The developed MPC method used the number of photons detected by each WLS fibre as a weight when calculating the positions of neutrons. The test detector implemented with the MPC method demonstrated that the effective pixel size and the spatial resolution were improved to 2 mm, corresponding to half the pitch of the WLS fibres.

关键词： data processing methods Neutron diffraction detectors Neutron detectors (cold, thermal, fast neutrons)

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Robustness of planar Fourier capture arrays to colour changes and lost pixels

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JOURNAL OF INSTRUMENTATION 2012年第1期7卷 C01061-C01061页

作者： Gill, P. R. Lee, C. Sivaramakrishnan, S. Molnar, A. Cornell Univ Sch Elect & Comp Engn Ithaca NY 14853 USA Univ Toronto Dept Psychol Toronto ON M5S 3G3 Canada

Planar Fourier capture arrays (PFCAs) are optical sensors built entirely in standard microchip manufacturing flows. PFCAs are composed of ensembles of angle sensitive pixels (ASPs) that each report a single coefficient of the Fourier transform of the far-away scene. Here we characterize the performance of PFCAs under the following three non-optimal conditions. First, we show that PFCAs can operate while sensing light of a wavelength other than the design point. Second, if only a randomly-selected subset of 10% of the ASPs are functional, we can nonetheless reconstruct the entire far-away scene using compressed sensing. Third, if the wavelength of the imaged light is unknown, it can be inferred by demanding self-consistency of the outputs.

关键词： Image filtering data processing methods Analysis and statistical methods

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Temperature fitting of partially resolved rotational spectra

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JOURNAL OF INSTRUMENTATION 2012年第02期7卷 C02054-C02054页

作者： van Gessel, A. F. H. Hrycak, B. Jasinski, M. Mizeraczyk, J. van der Mullen, J. J. A. M. Bruggeman, P. J. Eindhoven Univ Technol Dept Appl Phys NL-5600 MB Eindhoven Netherlands Polish Acad Sci Szewalski Inst Fluid Flow Machinery Ctr Plasma & Laser Engn PL-80231 Gdansk Poland

In this paper we present a method to automatically fit the temperature of a rotational spectrum. It is shown that this fitting method yields similar results as the traditional Boltzmann plot, but is applicable in situations where lines of the spectrum overlap. The method is demonstrated on rotational spectra of nitric oxide from an atmospheric pressure microwave plasma jet operated with a flow of helium and air, obtained with two different methods: laser induced fluorescence and optical emission spectroscopy. Axial profiles of the rotational temperatures are presented for the ground NO X state and the excited NO A state.

关键词： data processing methods Plasma diagnostics - interferometry, spectroscopy and imaging

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Contrast optimization in X-ray radiography with single photon counting imagers of Medipix type

Contrast optimization in X-ray radiography with single photo...

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14th International Workshop on Radiation Imaging Detectors

作者： Jandejsek, I. Dammer, J. Jakubek, J. Vavrik, D. Zemlicka, J. Czech Tech Univ Inst Expt & Appl Phys Prague 12800 2 Czech Republic Acad Sci Czech Republ Vvi Inst Theoret & Appl Mech Prague 19000 9 Czech Republic Charles Univ Prague Fac Med 1 Prague 10000 2 Czech Republic

Systematical measurement and optimization of the image contrast in the terms of the signal to noise ratio (SNR) reached by two detector systems Medipix2 (Si sensor) and Flat Panel (Scintillator + CMOS) is the aim of this work. The measurement is carried out with micro-focus X-ray source and aluminum step phantom specimen of various thicknesses. The SNR is computed from measured image data for various combination of aluminum thicknesses and in dependence on tube voltage and acquisition time. On the basis of the results, the comparison of two detector systems is done and the illustrative SNR optimization process for a hypothetical and real samples is demonstrated.

关键词： X-ray detectors X-ray radiography and digital radiography (DR) data processing methods Inspection with x-rays

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FITPix data preprocessing pipeline for the Timepix single particle pixel detector

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JOURNAL OF INSTRUMENTATION 2012年第04期7卷 C04011-C04011页

作者： Kraus, V. Holik, M. Jakubek, J. Georgiev, V. Czech Tech Univ Inst Expt & Appl Phys CR-16635 Prague 2 Czech Republic Univ W Bohemia Fac Elect Engn Plzen Czech Republic

The semiconductor pixel detector Timepix contains an array of 256 x 256 square pixels with a pitch of 55 mu m. The single quantum counting detector Timepix can also provide information about the energy or arrival time of a particle from every single pixel. This device is a powerful tool for radiation imaging and ionizing particle tracking. The Timepix device can be read-out via a serial or parallel interface enabling speeds of 100 fps or 3200 fps, respectively. The device can be connected to a PC via the USB 2.0 based interface FITPix, which currently supports the serial output of Timepix reaching a speed of 90 fps. FITPix supports adjustable clock frequency and hardware triggering which is a useful tool for the synchronized operation of multiple devices. The FITPix interface can handle up to 16 detectors in daisy chain. The complete system including the FITPix interface and Timepix detector is controlled from the PC by the Pixelman software package. A pipeline structure is now implemented in the new version of the readout interface of FITPix. This version also supports parallel Timepix readout. The pipeline architecture brings the possibility of data preprocessing directly in the hardware. The first pipeline stage converts the raw Timepix data into the form of a matrix or stream of pixel values. Another stage performs further data processing such as event thresholding and data compression. Complex data processing currently performed by Pixelman in the PC is significantly reduced in this way. The described architecture together with the parallel readout increases data throughput reaching a higher frame-rate and reducing the dead time. Significant data compression is performed directly in the hardware especially for sparse data sets from particle tracking applications. The data frame size is typically compressed by factor of 10-100.

关键词： data processing methods Front-end electronics for detector readout Modular electronics Electronic detector readout concepts (solid-state)

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