The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
N. P. Hawkes - One of the best experts on this subject based on the ideXlab platform.
-
Verification of the Digital discrimination of neutrons and rays using pulse gradient analysis by Digital measurement of time of flight
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2020Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, David J. Thomas, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF
-
Sample-interpolation timing: An optimized technique for the Digital measurement of time of flight for γ rays and neutrons at relatively low Sampling rates
Measurement Science and Technology, 2009Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, A.j. Boston, Anthony J. Peyton, P. J. Nolan, N. P. HawkesAbstract:A unique, Digital time pick-off method, known as sample-interpolation timing (SIT) is described. This method demonstrates the possibility of improved timing resolution for the Digital measurement of time of flight compared with Digital replica-analogue time pick-off methods for signals sampled at relatively low rates. Three analogue timing methods have been replicated in the Digital domain (leading-edge, crossover and constant-fraction timing) for pulse data sampled at 8 GSa s-1. Events arising from the 7Li(p, n)7Be reaction have been detected with an EJ-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Sample-interpolation timing was developed solely for the Digital domain and thus performs more efficiently on Digital signals compared with analogue time pick-off methods replicated Digitally, especially for fast signals that are sampled at rates that current affordable and portable devices can achieve. Sample interpolation can be applied to any analogue timing method replicated Digitally and thus also has the potential to exploit the generic capabilities of analogue techniques with the benefits of operating in the Digital domain. A threshold in Sampling rate with respect to the signal pulse width is observed beyond which further improvements in timing resolution are not attained. This advance is relevant to many applications in which time-of-flight measurement is essential. © 2009 IOP Publishing Ltd.
-
Verification of the Digital discrimination of neutrons and γ rays using pulse gradient analysis by Digital measurement of time of flight.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007Co-Authors: M. D. Aspinall, R. O. Mackin, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, Malcolm J. Joyce, David J. Thomas, Zina Jarrah, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF.
E. Bertolucci - One of the best experts on this subject based on the ideXlab platform.
-
Investigation on semi-insulating GaAs detectors using laser-induced current pulses
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2020Co-Authors: E. Bertolucci, Giovanni Mettivier, M. Quattrocchi, Paolo Russo, Adriano Cola, Fabio Quaranta, Lorenzo Vasanelli, Maria Giuseppina Bisogni, M. Conti, U. BottigliAbstract:Current pulses produced by absorption of picosecond near-infrared light pulses have been used in order to analyze the shape of the electric field and charge transport properties in semi-insulating (ST) GaAs Schottky barrier X- and gamma-ray detectors. Diodes with square pads of side 0.2-1 mm on 200, 600 and 1000-mum-thick SI GaAs substrates have been illuminated from the front (Schottky) contact, from the back (ohmic) side and laterally between the contacts. Current pulses have been recorded with a fast Digital Sampling Oscilloscope, at room temperature, without using any signal amplification. Current and charge pulse shapes have been analyzed as a function of reverse bias voltage, positioned on the detector surface and optical wavelength around the near-infrared absorption edge of GaAs. The wavelength tuning allows for increasing light penetration lengths. Signal analysis gives the peak current, total collected charge and the charge collection time, which are related to the average strength of the electric field and the drift velocity field, while pulse shape depends on the local value of these fields. The experimental results show that a complete detector characterization is feasible with this optical technique, in a manner analogous to that commonly done with gamma- or X- or alpha-ray sources, with the advantage of analyzing the charge collection time. An additional advantage is represented by focusing the light beam on the detector surface, for 1D or 2D scan. (C) 2001 Elsevier Science B.V. All rights reserved
-
Response of semi-insulating GaAs detectors to near-infrared picosecond light pulses
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: Paolo Russo, M. Quattrocchi, E. BertolucciAbstract:Abstract Semi-insulating gallium arsenide (SI-GaAs) detectors, in the form of Schottky diodes, have been irradiated from the front or from the back contact or from the side, with light pulses from picosecond laser source, tunable in the range of 780–1020 nm and focused to a 50–100 μm spot on the surface of the detector. Energy per pulse was in the range of 4–25 pJ, with a 10 or 100 Hz repetition rate. Each pulse mimics the interaction of a single energetic particle with the substrate, but with a photon mean free path modulated in the range of 1 μm–1 cm, depending on the light wavelength. The SI-GaAs substrates have a thickness of 200 μm (VGF grown), or 600 μm (LEC) or 1000 μm (VGF). The time response of the detectors, analysed with the Transient Current Technique (using a fast Digital Sampling Oscilloscope) in terms of peak signal amplitude and charge rise time, has been evaluated as a function of: reverse voltage bias (50–1200 V), light wavelength (780–1020 nm), side position between the electrodes, position on the front contact. The results are: (1) the shape of the transient current signal may show the presence of two peaks, about 1 ns apart; (2) the charge rise time, considered to be dominated by the charge collection time, is between 2 and 13 ns; (3) the charge rise time, as due to electron drift or hole drift in the region between the contacts, has been measured as 2–5 ns, also dependent on the applied bias; (4) the transient current (exponential) decay time, for front or back irradiation, increases with the bias voltage up to 2–20 ns and these data are considered to be consistent with the electron detrapping time; (5) under reverse bias, for 1 mm pad side and a large ohmic contact on the back, the electric field extends around the front contact up to about 200 μm.
-
Investigation on semi-insulating GaAs detectors using laser-induced current pulses
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: E. Bertolucci, Marcello Rossetti Conti, Giovanni Mettivier, M. Quattrocchi, Paolo Russo, Adriano Cola, Fabio Quaranta, Lorenzo Vasanelli, Maria Giuseppina Bisogni, U. BottigliAbstract:Abstract Current pulses produced by absorption of picosecond near-infrared light pulses have been used in order to analyze the shape of the electric field and charge transport properties in semi-insulating (SI) GaAs Schottky barrier X- and gamma-ray detectors. Diodes with square pads of side 0.2–1 mm on 200, 600 and 1000-μm-thick SI GaAs substrates have been illuminated from the front (Schottky) contact, from the back (ohmic) side and laterally between the contacts. Current pulses have been recorded with a fast Digital Sampling Oscilloscope, at room temperature, without using any signal amplification. Current and charge pulse shapes have been analyzed as a function of reverse bias voltage, positioned on the detector surface and optical wavelength around the near-infrared absorption edge of GaAs. The wavelength tuning allows for increasing light penetration lengths. Signal analysis gives the peak current, total collected charge and the charge collection time, which are related to the average strength of the electric field and the drift velocity field, while pulse shape depends on the local value of these fields. The experimental results show that a complete detector characterization is feasible with this optical technique, in a manner analogous to that commonly done with gamma- or X- or alpha-ray sources, with the advantage of analyzing the charge collection time. An additional advantage is represented by focusing the light beam on the detector surface, for 1D or 2D scan.
M. D. Aspinall - One of the best experts on this subject based on the ideXlab platform.
-
Verification of the Digital discrimination of neutrons and rays using pulse gradient analysis by Digital measurement of time of flight
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2020Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, David J. Thomas, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF
-
An investigation of the Digital discrimination of neutrons and γ rays with organic scintillation detectors using an artificial neural network
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2009Co-Authors: M. D. Aspinall, Xiandong Ma, Malcolm J. JoyceAbstract:The discrimination of neutron and γ-ray events in an organic scintillator has been investigated by using a method based on an artificial neural network (ANN). Voltage pulses arising from an EJ-301 organic liquid scintillation detector in a mixed radiation field have been recorded with a fast Digital Sampling Oscilloscope. Piled-up events have been disentangled using a pile-up management unit based on a fitting method. Each individual pulse has subsequently been sent to a discrimination unit which discriminates neutron and γ-ray events with a method based on an artificial neural network. This discrimination technique has been verified by the corresponding mixed-field data assessed by time of flight (TOF). It is shown that the characterization of the neutrons and photons achieved by the discrimination method based on the ANN is consistent with that afforded by TOF. This approach enables events that are often as a result of scattering or pile-up to be identified and returned to the data set and affords Digital discrimination of mixed radiation fields in a broad range of environments on the basis of training obtained with a single TOF dataset.
-
Sample-interpolation timing: An optimized technique for the Digital measurement of time of flight for γ rays and neutrons at relatively low Sampling rates
Measurement Science and Technology, 2009Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, A.j. Boston, Anthony J. Peyton, P. J. Nolan, N. P. HawkesAbstract:A unique, Digital time pick-off method, known as sample-interpolation timing (SIT) is described. This method demonstrates the possibility of improved timing resolution for the Digital measurement of time of flight compared with Digital replica-analogue time pick-off methods for signals sampled at relatively low rates. Three analogue timing methods have been replicated in the Digital domain (leading-edge, crossover and constant-fraction timing) for pulse data sampled at 8 GSa s-1. Events arising from the 7Li(p, n)7Be reaction have been detected with an EJ-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Sample-interpolation timing was developed solely for the Digital domain and thus performs more efficiently on Digital signals compared with analogue time pick-off methods replicated Digitally, especially for fast signals that are sampled at rates that current affordable and portable devices can achieve. Sample interpolation can be applied to any analogue timing method replicated Digitally and thus also has the potential to exploit the generic capabilities of analogue techniques with the benefits of operating in the Digital domain. A threshold in Sampling rate with respect to the signal pulse width is observed beyond which further improvements in timing resolution are not attained. This advance is relevant to many applications in which time-of-flight measurement is essential. © 2009 IOP Publishing Ltd.
-
Verification of the Digital discrimination of neutrons and γ rays using pulse gradient analysis by Digital measurement of time of flight.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007Co-Authors: M. D. Aspinall, R. O. Mackin, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, Malcolm J. Joyce, David J. Thomas, Zina Jarrah, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF.
Michael Stark - One of the best experts on this subject based on the ideXlab platform.
-
RFID-TA - Measurement instrument selection for very high bit rate contactless transponder evaluation
2011 IEEE International Conference on RFID-Technologies and Applications, 2011Co-Authors: David Seebacher, Michael Gebhart, Michael StarkAbstract:In this paper we discuss properties of the Digital Sampling Oscilloscope versus signal analyzer as instrument in the test bench to characterize ISO/IEC14443 compliant contactless communication devices. An extension to the existing near-field communication (NFC) standard specifies very high bit rates (VHBR) in the range of 10 Mbit/s for the Reader to Transponder communication link. One draft specification takes advantage of sophisticated signal processing and clever coding, to allow an energy-efficient contactless system, compliant to existing frequency regulation and to typical Reader hardware, which can also be used in mobile applications such as NFC in Smartphones. Considerations for the test bench to characterize this communication air interface are of general interest also for existing RFID standards in the 13.56 MHz frequency band.
-
Measurement instrument selection for very high bit rate contactless transponder evaluation
2011 IEEE International Conference on RFID-Technologies and Applications, 2011Co-Authors: David Seebacher, Michael Gebhart, Michael StarkAbstract:In this paper we discuss properties of the Digital Sampling Oscilloscope versus signal analyzer as instrument in the test bench to characterize ISO/IEC14443 compliant contactless communication devices. An extension to the existing near-field communication (NFC) standard specifies very high bit rates (VHBR) in the range of 10 Mbit/s for the Reader to Transponder communication link. One draft specification takes advantage of sophisticated signal processing and clever coding, to allow an energy-efficient contactless system, compliant to existing frequency regulation and to typical Reader hardware, which can also be used in mobile applications such as NFC in Smartphones. Considerations for the test bench to characterize this communication air interface are of general interest also for existing RFID standards in the 13.56 MHz frequency band.
A.j. Boston - One of the best experts on this subject based on the ideXlab platform.
-
Verification of the Digital discrimination of neutrons and rays using pulse gradient analysis by Digital measurement of time of flight
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2020Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, David J. Thomas, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF
-
Sample-interpolation timing: An optimized technique for the Digital measurement of time of flight for γ rays and neutrons at relatively low Sampling rates
Measurement Science and Technology, 2009Co-Authors: M. D. Aspinall, M. J. Joyce, R. O. Mackin, Z. Jarrah, A.j. Boston, Anthony J. Peyton, P. J. Nolan, N. P. HawkesAbstract:A unique, Digital time pick-off method, known as sample-interpolation timing (SIT) is described. This method demonstrates the possibility of improved timing resolution for the Digital measurement of time of flight compared with Digital replica-analogue time pick-off methods for signals sampled at relatively low rates. Three analogue timing methods have been replicated in the Digital domain (leading-edge, crossover and constant-fraction timing) for pulse data sampled at 8 GSa s-1. Events arising from the 7Li(p, n)7Be reaction have been detected with an EJ-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Sample-interpolation timing was developed solely for the Digital domain and thus performs more efficiently on Digital signals compared with analogue time pick-off methods replicated Digitally, especially for fast signals that are sampled at rates that current affordable and portable devices can achieve. Sample interpolation can be applied to any analogue timing method replicated Digitally and thus also has the potential to exploit the generic capabilities of analogue techniques with the benefits of operating in the Digital domain. A threshold in Sampling rate with respect to the signal pulse width is observed beyond which further improvements in timing resolution are not attained. This advance is relevant to many applications in which time-of-flight measurement is essential. © 2009 IOP Publishing Ltd.
-
Verification of the Digital discrimination of neutrons and γ rays using pulse gradient analysis by Digital measurement of time of flight.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2007Co-Authors: M. D. Aspinall, R. O. Mackin, N. P. Hawkes, Anthony J. Peyton, P. J. Nolan, B. D’mellow, Malcolm J. Joyce, David J. Thomas, Zina Jarrah, A.j. BostonAbstract:The discrimination of neutron and γ-ray events in an organic scintillator with the pulse gradient analysis (PGA) method is verified against that achieved via the Digital measurement of time of flight (TOF). Events arising from the reaction have been detected with an LS-301 organic liquid scintillator and recorded with a fast Digital Sampling Oscilloscope. Both qualitative (via the cross-referencing of scatter diagrams) and quantitative (via the neutron/γ-ray ratio) comparisons are reported. Discrimination afforded by the PGA method is observed to be consistent with that achieved by Digital TOF.