Analysis of single-photon time resolution of FBK silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Acerbi, Fabio, E-mail: acerbi@fbk.eu; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

2015-07-01

We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red–Green–Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm{sup 2} and 3×3 mm{sup 2} SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution.

High resolution soft X-Ray spectrometer with 5-picosecond time-resolution for laser-produced plasma diagnostics

International Nuclear Information System (INIS)

Mexmain, J.M.; Bourgade, J.L.; Louis-Jacquet, M.; Mascureau, J. de; Sauneuf, R.; Schwob, J.L.

1987-01-01

A new XUV spectrometer designed to have a time-resolution of 3 ps and a spectral resolution of 0.1 A is described. It is basically a modified version of a Schwob-Fraenkel spectrometer, which is coupled to a new ultrafast electronic streak camera

A 41 ps ASIC time-to-digital converter for physics experiments

International Nuclear Information System (INIS)

Russo, Stefano; Petra, Nicola; De Caro, Davide; Barbarino, Giancarlo; Strollo, Antonio G.M.

2011-01-01

We present a novel Time-to-Digital (TDC) converter for physics experiments. Proposed TDC is based on a synchronous counter and an asynchronous fine interpolator. The fine part of the measurement is obtained using NORA inverters that provide improved resolution. A prototype IC was fabricated in 180 nm CMOS technology. Experimental measurements show that proposed TDC features 41 ps resolution associated with 0.35LSB differential non-linearity, 0.77LSB integral non-linearity and a negligible single shot precision. The whole dynamic range is equal to 18μs. The proposed TDC is designed using a flash architecture that reduces dead time. Data reported in the paper show that our design is well suited for present and future particle physics experiments.

Systematic test on fast time resolution parallel plate avalanche counter

International Nuclear Information System (INIS)

Chen Yu; Li Guangwu; Gu Xianbao; Chen Yanchao; Zhang Gang; Zhang Wenhui; Yan Guohong

2011-01-01

Systematic test on each detect unit of parallel plate avalanche counter (PPAC) used in the fission multi-parameter measurement was performed with a 241 Am α source to get the time resolution and position resolution. The detectors work at 600 Pa flowing isobutane and with-600 V on cathode. The time resolution was got by TOF method and the position resolution was got by delay line method. The time resolution of detect units is better than 400 ps, and the position resolution is 6 mm. The results show that the demand of measurement is fully covered. (authors)

Time-gated single-photon detection module with 110 ps transition time and up to 80 MHz repetition rate

Energy Technology Data Exchange (ETDEWEB)

Buttafava, Mauro, E-mail: mauro.buttafava@polimi.it; Boso, Gianluca; Ruggeri, Alessandro; Tosi, Alberto [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Dalla Mora, Alberto [Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy)

2014-08-15

We present the design and characterization of a complete single-photon counting module capable of time-gating a silicon single-photon avalanche diode with ON and OFF transition times down to 110 ps, at repetition rates up to 80 MHz. Thanks to this sharp temporal filtering of incoming photons, it is possible to reject undesired strong light pulses preceding (or following) the signal of interest, allowing to increase the dynamic range of optical acquisitions up to 7 decades. A complete experimental characterization of the module highlights its very flat temporal response, with a time resolution of the order of 30 ps. The instrument is fully user-configurable via a PC interface and can be easily integrated in any optical setup, thanks to its small and compact form factor.

Time-gated single-photon detection module with 110 ps transition time and up to 80 MHz repetition rate

International Nuclear Information System (INIS)

Buttafava, Mauro; Boso, Gianluca; Ruggeri, Alessandro; Tosi, Alberto; Dalla Mora, Alberto

2014-01-01

We present the design and characterization of a complete single-photon counting module capable of time-gating a silicon single-photon avalanche diode with ON and OFF transition times down to 110 ps, at repetition rates up to 80 MHz. Thanks to this sharp temporal filtering of incoming photons, it is possible to reject undesired strong light pulses preceding (or following) the signal of interest, allowing to increase the dynamic range of optical acquisitions up to 7 decades. A complete experimental characterization of the module highlights its very flat temporal response, with a time resolution of the order of 30 ps. The instrument is fully user-configurable via a PC interface and can be easily integrated in any optical setup, thanks to its small and compact form factor

Development of high speed integrated circuit for very high resolution timing measurements

International Nuclear Information System (INIS)

Mester, Christian

2009-10-01

A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

Development of high speed integrated circuit for very high resolution timing measurements

Energy Technology Data Exchange (ETDEWEB)

Mester, Christian

2009-10-15

A multi-channel high-precision low-power time-to-digital converter application specific integrated circuit for high energy physics applications has been designed and implemented in a 130 nm CMOS process. To reach a target resolution of 24.4 ps, a novel delay element has been conceived. This nominal resolution has been experimentally verified with a prototype, with a minimum resolution of 19 ps. To further improve the resolution, a new interpolation scheme has been described. The ASIC has been designed to use a reference clock with the LHC bunch crossing frequency of 40 MHz and generate all required timing signals internally, to ease to use within the framework of an LHC upgrade. Special care has been taken to minimise the power consumption. (orig.)

Can Transient Phenomena Help Improving Time Resolution in Scintillators?

CERN Document Server

Lecoq, P; Vasiliev, A

2014-01-01

The time resolution of a scintillator-based detector is directly driven by the density of photoelectrons generated in the photodetector at the detection threshold. At the scintillator level it is related to the intrinsic light yield, the pulse shape (rise time and decay time) and the light transport from the gamma-ray conversion point to the photodetector. When aiming at 10 ps time resolution, fluctuations in the thermalization and relaxation time of hot electrons and holes generated by the interaction of ionization radiation with the crystal become important. These processes last for up to a few tens of ps and are followed by a complex trapping-detrapping process, Poole-Frenkel effect, Auger ionization of traps and electron-hole recombination, which can last for a few ns with very large fluctuations. This paper will review the different processes at work and evaluate if some of the transient phenomena taking place during the fast thermalization phase can be exploited to extract a time tag with a precision in...

Development of a geometry-compensated neutron time-of-flight detector for ICF applications with approximately 200 ps time response

International Nuclear Information System (INIS)

Murphy, T.J.; Lerche, R.A.

1992-01-01

Current-mode neutron time-of-flight detectors are used on Nova for neutron yield, ion temperature, and neutron emission time measurements. Currently used detectors are limited by the time response of the microchannel plate photomultiplier tubes used with the scintillators, scintillator decay time, scintillator thickness, and oscilloscope response time. A change in the geometry of the scintillator allows one to take advantage of the increased time resolution made possible by more advanced transient recorders and microchannel plate photomultiplier tubes. A prototype detector has been designed to incorporate these changes, and could potentially yield time resolution of less than 150 ps. Experimental results are presented demonstrating an ion temperature measurement of a direct-drive DT implosion on Nova

Low-Power Amplifier-Discriminators for High Time Resolution Detection

CERN Document Server

Despeisse, M; Anghinolfi, F; Tiuraniemi, S; Osmic, F; Riedler, P; Kluge, A; Ceccucci, A

2009-01-01

Low-power amplifier-discriminators based on a so-called NINO architecture have been developed with high time resolution for the readout of radiation detectors. Two different circuits were integrated in the NINO13 chip, processed in IBM 130 nm CMOS technology. The LCO version (Low Capacitance and consumption Optimization) was designed for potential use as front-end electronics in the Gigatracker of the NA62 experiment at CERN. It was developed as pixel readout for solid-state pixel detectors to permit minimum ionizing particle detection with less than 180 ps rms resolution per pixel on the output pulse, for power consumption below 300 mu W per pixel. The HCO version (High Capacitance Optimization) was designed with 4 mW power consumption per channel to provide timing resolution below 20 ps rms on the output pulse, for charges above 10 fC. Results presented show the potential of the LCO and HCO circuits for the precise timing readout of solid-state detectors, vacuum tubes or gas detectors, for applications in h...

High resolution time-of-flight measurements in small and large scintillation counters

International Nuclear Information System (INIS)

D'Agostini, G.; Marini, G.; Martellotti, G.; Massa, F.; Rambaldi, A.; Sciubba, A.

1981-01-01

In a test run, the experimental time-of-flight resolution was measured for several different scintillation counters of small (10 x 5 cm 2 ) and large (100 x 15 cm 2 and 75 x 25 cm 2 ) area. The design characteristics were decided on the basis of theoretical Monte Carlo calculations. We report results using twisted, fish-tail, and rectangular light- guides and different types of scintillator (NE 114 and PILOT U). Time resolution up to approx. equal to 130-150 ps fwhm for the small counters and up to approx. equal to 280-300 ps fwhm for the large counters were obtained. The spatial resolution from time measurements in the large counters is also reported. The results of Monte Carlo calculations on the type of scintillator, the shape and dimensions of the light-guides, and the nature of the external wrapping surfaces - to be used in order to optimize the time resolution - are also summarized. (orig.)

Chaos and dynamics on 0.5--300 ps time scales in vibrationally excited acetylene: Fourier transform of stimulated-emission pumping spectrum

International Nuclear Information System (INIS)

Pique, J.P.; Chen, Y.; Field, R.W.; Kinsey, J.L.

1987-01-01

A recently proposed technique based on the Fourier transform of the spectrum is applied to the stimulated-emission pumping spectrum of acetylene at --26 500 cm/sup -1/ above the vibrational ground state. Correlations on two different time scales (--3 and --45 ps) were found from analysis of low-resolution (0.3 cm/sup -1/) and high-resolution (0.05 cm/sup -1/) spectra, respectively. Additional structure produced dynamic information on a wider (0.5--300 ps) time scale. The results show that acetylene at 26 500 cm/sup -1/ is in the transition from the regular to the chaotic regime

Time resolution deterioration with increasing crystal length in a TOF-PET system

CERN Document Server

Gundacker, S; Auffray, E; Jarron, P; Meyer, T; Lecoq, P

2014-01-01

Highest time resolution in scintillator based detectors is becoming more and more important. In medical detector physics L(Y)SO scintillators are commonly used for time of flight positron emission tomography (TOF-PET). Coincidence time resolutions (CTRs) smaller than 100 ps FWHM are desirable in order to improve the image signal to noise ratio and thus give benefit to the patient by shorter scanning times. Also in high energy physics there is the demand to improve the timing capabilities of calorimeters down to 10 ps. To achieve these goals it is important to study the whole chain, i.e. the high energy particle interaction in the crystal, the scintillation process itself, the scintillation light transfer in the crystal, the photodetector and the electronics. Time resolution measurements for a PET like system are performed with the time-over-threshold method in a coincidence setup utilizing the ultra-fast amplifier-discriminator NINO. With 2×2×3 mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially avai...

Time resolution in scintillator based detectors for positron emission tomography

International Nuclear Information System (INIS)

Gundacker, S.

2014-01-01

In the domain of medical photon detectors L(Y)SO scintillators are used for positron emission tomography (PET). The interest for time of flight (TOF) in PET is increasing since measurements have shown that new crystals like L(Y)SO coupled to state of the art photodetectors, e.g. silicon photomultipliers (SiPM), can reach coincidence time resolutions (CTRs) of far below 500ps FWHM. To achieve these goals it is important to study the processe in the whole detection chain, i.e. the high energy particle or gamma interaction in the crystal, the scintillation process itself, the light propagation in the crystal with the light transfer to the photodetector, and the electronic readout. In this thesis time resolution measurements for a PET like system are performed in a coincidence setup utilizing the ultra fast amplifier discriminator NINO. We found that the time-over-threshold energy information provided by NINO shows a degradation in energy resolution for higher SiPM bias voltages. This is a consequence of the increasing dark count rate (DCR) of the SiPM with higher bias voltages together with the exponential decay of the signal. To overcome this problem and to operate the SiPM at its optimum voltage in terms of timing we developed a new electronic board that employs NINO only as a low noise leading edge discriminator together with an analog amplifier which delivers the energy information. With this new electronic board we indeed improved the measured CTR by about 15%. To study the limits of time resolution in more depth we measured the CTR with 2x2x3mm3 LSO:Ce codoped 0.4%Ca crystals coupled to commercially available SiPMs (Hamamatsu S10931-50P MPPC) and achieved a CTR of 108±5ps FWHM at an energy of 511keV. We determined the influence of the data acquisition system and the electronics on the CTR to be 27±2ps FWHM and thus negligible. To quantitatively understand the measured values, we developed a Monte Carlo simulation tool in MATLAB that incorporates the timing

A 9-Channel, 100 ps LSB Time-to-Digital Converter for the NA62 Gigatracker Readout ASIC (TDCpix)

International Nuclear Information System (INIS)

Perktold, L; Rinella, G Aglieri; Noy, M; Kluge, A; Kloukinas, K; Kaplon, J; Jarron, P; Morel, M; Fiorini, M; Martin, E

2012-01-01

The TDCpix ASIC is the readout chip for the Gigatracker station of the NA62 experiment. Each station of the Gigatracker needs to provide time stamping of individual particles to 200 ps-rms or better. Bump-bonded to the pixel sensor the ASIC serves an array of 40 columns x 40 pixels. The high precision time measurement of the discriminated hit signals is accomplished with a set of 40 TDCs sitting in the End-Of-Column region of the ASIC. Each TDC provides 9 channels per column. For the time-to-digital converter (TDC) a delay-locked-loop (DLL) approach is employed to achieve a constant time binning of 100 ps. Simulation results show that an average rms time resolution of 33 ps with a power consumption of the TDC better than 33 mW per column is achieved. This contribution will present the design, simulation results and implementation challenges of the TDC.

Picosecond resolution on relativistic heavy ions' time-of-flight measurement

International Nuclear Information System (INIS)

Ebran, A.; Taieb, J.; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

2013-01-01

We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment—which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron–accelerator (ELSA) at CEA–DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution

Time-of-flight resolution of scintillating counters with Burle 85001 microchannel plate photomultipliers in comparison with Hamamatsu R2083

Energy Technology Data Exchange (ETDEWEB)

Baturin, V. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Burkert, V. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Kim, W. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)]. E-mail: wooyoung@jlab.org; Majewsky, S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Park, K. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Popov, V. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Smith, E.S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Son, D. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Stepanyan, S.S. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Zorn, C. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

2006-06-15

Improvements in the time resolution of the CEBAF Large Acceptance Spectrometer (CLAS) below {approx}50ps will be required for experiments using the planned upgraded accelerator facility at Jefferson Lab. The improved time resolution will allow particle identification using time-of-flight techniques to be used effectively up to the proposed operating energy of 12GeV. The challenge of achieving this time resolution over a relatively large area is compounded because the photomultipliers (PM) in the CLAS 'time-zero' scintillating counters must operate in very high magnetic fields. Therefore, we have studied the resolution of 'time-zero' prototypes with microchannel plate PMs 85001-501 from Burle. For reference and comparison, measurements were also made using the standard PMs R2083 from Hamamatsu using two timing methods. The cosmic ray method, which utilizes three identical scintillating counters (Bicron BC-408, 2x3x50cm{sup 3}) with PMs at the ends, yields {sigma}{sub R2083}=59.1+/-0.7ps. The location method of particles from a radiative source with known coordinates has been used to compare timing resolutions of R2083 and 85001-501. This method yields {sigma}{sub R2083}=59.5+/-0.7ps and it also provides an estimate of the number of primary photoelectrons. For the microchannel plate PM from Burle the method yields {sigma}{sub 85001}=130+/-4ps due to lower number of primary photoelectrons.

Coincidence resolution time of two small scintillators coupled to high quantum-efficiency photomultipliers in a PET-like system

Science.gov (United States)

Galetta, G.; De Leo, R.; Garibaldi, F.; Grodzicka, M.; Lagamba, L.; Loddo, F.; Masiello, G.; Nappi, E.; Perrino, R.; Ranieri, A.; Szczęśniak, T.

2014-03-01

The lower limit of the time resolution for a positron emission tomography (PET) system has been measured for two scintillator types, LYSO:Ce and LuAG:Pr. Small dimension crystals and ultra bi-alkali phototubes have been used in order to increase the detected scintillation photons. Good timing resolutions of 118 ps and 223 ps FWHM have been obtained for two LYSO and two LuAG, respectively, exposed to a 22Na source.

The implementing of high resolution time measuring circuit based on FPGA

International Nuclear Information System (INIS)

Zhang Ji; Zeng Yun; Wang Zheng; Li Quiju; Lu Jifang; Wu Jinyuan

2011-01-01

It presents the implementing of TDC based on FPGA. The fine timing function part is accomplished through the time interpolators that are composed of the carry chain of intrinsic adders in FPGA. This architecture dates back to the latest technology-WUTDC (Wave Union TDC) that is developed to sub-divide the ultra-wide bins and improve the measure resolution. The board and the online test have been proved that the linearity of converters is satisfying and the time resolution is better than 40 ps. (authors)

A high resolution animal PET scanner using compact PS-PMT detectors

International Nuclear Information System (INIS)

Watanabe, M.; Okada, H.; Shimizu, K.; Omura, T.

1996-01-01

A new high resolution PET scanner dedicated to animal studies has been designed, built and tested. The system utilizes 240 block detectors, each of which consists of a new compact position-sensitive photomultiplier tube (PS-PMT) and an 8 x 4 BGO array. A total number of 7,680 crystals (480 per ring) are positioned to form a 508 mm diameter of 16 detector rings with 7.2 mm pitch and 114 mm axial field of view (FOV). The system is designed to perform activation studies using a monkey in a sitting position. The data can be acquired in either 2D or 3D mode, where the slice collimators are retracted in 3D mode. The transaxial resolution is 2.6 mm FWHM at the center of the FOV, and the average axial resolution on the axis of the ring is 3.3 mm FWHM in the direct slice and 3.2 mm FWHM in the cross slice. The scatter fraction, sensitivity and count rate performance were evaluated for a 10 cm diameter cylindrical phantom. The total system sensitivity is 2.3 kcps/kBq/ml in 2D mode and 22.8 kcps/kBq/ml in 3D mode. The noise equivalent count rate with 3D mode is equivalent to that with 2D mode at five times higher radioactivity level. The applicable imaging capabilities of the scanner was demonstrated by animal studies with a monkey

Pulse-dilation enhanced gated optical imager with 5 ps resolution (invited)

Energy Technology Data Exchange (ETDEWEB)

Hilsabeck, T. J.; Kilkenny, J. D. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Hares, J. D.; Dymoke-Bradshaw, A. K. L. [Kentech Instruments Ltd., Wallingford, Oxfordshire OX10 (United Kingdom); Bell, P. M.; Koch, J. A.; Celliers, P. M.; Bradley, D. K.; McCarville, T.; Pivovaroff, M.; Soufli, R.; Bionta, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2010-10-15

A 5 ps gated framing camera was demonstrated using the pulse-dilation of a drifting electron signal. The pulse-dilation is achieved by accelerating a photoelectron derived information pulse with a time varying potential [R. D. Prosser, J. Phys. E 9, 57 (1976)]. The temporal dependence of the accelerating potential causes a birth time dependent axial velocity dispersion that spreads the pulse as it transits a drift region. The expanded pulse is then imaged with a conventional gated microchannel plate based framing camera and the effective gating time of the combined instrument is reduced over that of the framing camera alone. In the drift region, electron image defocusing in the transverse or image plane is prevented with a large axial magnetic field. Details of the unique issues associated with rf excited photocathodes were investigated numerically and a prototype instrument based on this principle was recently constructed. Temporal resolution of the instrument was measured with a frequency tripled femtosecond laser operating at 266 nm. The system demonstrated 20x temporal magnification and the results are presented here. X-ray image formation strategies and photometric calculations for inertial confinement fusion implosion experiments are also examined.

Picosecond resolution on relativistic heavy ions' time-of-flight measurement

Energy Technology Data Exchange (ETDEWEB)

Ebran, A., E-mail: adeline.ebran@cea.fr; Taieb, J., E-mail: julien.taieb@cea.fr; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

2013-11-11

We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment—which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron–accelerator (ELSA) at CEA–DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution.

A high time and spatial resolution MRPC designed for muon tomography

Science.gov (United States)

Shi, L.; Wang, Y.; Huang, X.; Wang, X.; Zhu, W.; Li, Y.; Cheng, J.

2014-12-01

A prototype of cosmic muon scattering tomography system has been set up in Tsinghua University in Beijing. Multi-gap Resistive Plate Chamber (MRPC) is used in the system to get the muon tracks. Compared with other detectors, MRPC can not only provide the track but also the Time of Flight (ToF) between two detectors which can estimate the energy of particles. To get a more accurate track and higher efficiency of the tomography system, a new type of high time and two-dimensional spatial resolution MRPC has been developed. A series of experiments have been done to measure the efficiency, time resolution and spatial resolution. The results show that the efficiency can reach 95% and its time resolution is around 65 ps. The cluster size is around 4 and the spatial resolution can reach 200 μ m.

Comparative timing measurements of LYSO and LFS-3 to achieve the best time resolution for TOF-PET

CERN Document Server

Doroud, K; Zichichi, A; Zuyeuski, R

2015-01-01

The best Coincidence Time Resolution (CTR) obtained so far – with very short crystals of 3–5 mm in length – reach values between 100 and 150 ps. Such crystals are not really practical for a TOF PET imaging device, since the sensitivity is quite small for the detection of the 511 keV gammas resulting from a positron annihilation. We present our setup and measurements using 15 mm length crystals; a length we regard as reasonable for a TOF-PET scanner. We have used a new series of Silicon Photo-Multipliers (SiPM) manufactured by Hamamatsu. These are the High Fill Factor (HFF) and Low Cross-Talk (LCT) Multi-Pixel Photon Counters (MPPC). We have compared three different crystals, LFS-3 (supplied by Zecotek) and two samples of LYSO (manufactured by Saint Gobain and CPI). We have obtained an excellent value of 148 ps for the Coincidence Time Resolution (CTR) with two LFS-3 crystals (15 mm long) mounted on each side of a 22Na radioactive source with the HFF-MPPCs at 3.3 V over-voltage. Our results are148 ps obt...

A 75 ps rms time resolution BiCMOS time to digital converter optimized for high rate imaging detectors

CERN Document Server

Hervé, C

2002-01-01

This paper presents an integrated time to digital converter (TDC) with a bin size adjustable in the range of 125 to 175 ps and a differential nonlinearity of +-0.3%. The TDC has four channels. Its architecture has been optimized for the readout of imaging detectors in use at Synchrotron Radiation facilities. In particular, a built-in logic flags piled-up events. Multi-hit patterns are also supported for other applications. Time measurements are extracted off chip at the maximum throughput of 40 MHz. The dynamic range is 14 bits. It has been fabricated in 0.8 mu m BiCMOS technology. Time critical inputs are PECL compatible whereas other signals are CMOS compatible. A second application specific integrated circuit (ASIC) has been developed which translates NIM electrical levels to PECL ones. Both circuits are used to assemble board level TDCs complying with industry standards like VME, NIM and PCI.

Reduced γ–γ time walk to below 50 ps using the multiplexed-start and multiplexed-stop fast-timing technique with LaBr_3(Ce) detectors

International Nuclear Information System (INIS)

Régis, J.-M.; Saed-Samii, N.; Rudigier, M.; Ansari, S.; Dannhoff, M.; Esmaylzadeh, A.; Fransen, C.; Gerst, R.-B.; Jolie, J.; Karayonchev, V.; Müller-Gatermann, C.; Stegemann, S.

2016-01-01

The electronic γ–γ fast-timing technique using arrays consisting of many LaBr_3(Ce) detectors is a powerful method to determine lifetimes of nuclear excited states with a lower limit of about 5 ps. This method requires the determination of the energy-dependent time walk of the zero time which is represented by the centroid of a prompt γ–γ time distribution. The full-energy peak versus full-energy peak prompt response difference which represents the linearly combined mean γ–γ time walk of a fast-timing array consisting of 8 LaBr_3(Ce) detectors was measured using a standard "1"5"2Eu γ-ray source for the energy region of 40–1408 keV. The data were acquired using a “multiplexed-start and multiplexed-stop” analogue electronics circuitry and analysed by employing the generalized centroid difference method. Concerning the cylindrical 1.5 in.×1.5 in. LaBr_3(Ce) crystals which are coupled to the Hamamatsu R9779 photomultiplier tubes, the best fast-timing array time resolution of 202(3) ps is obtained for the two prompt γ lines of "6"0Co by using the leading-edge timing principle. When using the zero-crossover timing principle the time resolution is degraded by up to 30%, dependent on the energy and the shaping delay time of the constant fraction discriminator model Ortec 935. The smallest γ–γ time walk to below 50 ps is obtained by using a shaping delay time of about 17 ns and an optimum “time-walk adjustment” needed for detector output pulses with amplitudes smaller than 400 mV.

Multichannel FPGA based MVT system for high precision time (20 ps RMS) and charge measurement

Science.gov (United States)

Pałka, M.; Strzempek, P.; Korcyl, G.; Bednarski, T.; Niedźwiecki, Sz.; Białas, P.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Gorgol, M.; Jasińska, B.; Kamińska, D.; Kajetanowicz, M.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Mohhamed, M.; Raczyński, L.; Rudy, Z.; Rundel, O.; Salabura, P.; Sharma, N. G.; Silarski, M.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Zieliński, M.; Zgardzińska, B.; Moskal, P.

2017-08-01

In this article it is presented an FPGA based Multi-Voltage Threshold (MVT) system which allows of sampling fast signals (1-2 ns rising and falling edge) in both voltage and time domain. It is possible to achieve a precision of time measurement of 20 ps RMS and reconstruct charge of signals, using a simple approach, with deviation from real value smaller than 10%. Utilization of the differential inputs of an FPGA chip as comparators together with an implementation of a TDC inside an FPGA allowed us to achieve a compact multi-channel system characterized by low power consumption and low production costs. This paper describes realization and functioning of the system comprising 192-channel TDC board and a four mezzanine cards which split incoming signals and discriminate them. The boards have been used to validate a newly developed Time-of-Flight Positron Emission Tomography system based on plastic scintillators. The achieved full system time resolution of σ(TOF) ≈ 68 ps is by factor of two better with respect to the current TOF-PET systems.

Multichannel low power time-to-digital converter card with 21 ps precision and full scale range up to 10 μs

International Nuclear Information System (INIS)

Tamborini, D.; Portaluppi, D.; Villa, F.; Tosi, A.; Tisa, S.

2014-01-01

We present a Time-to-Digital Converter (TDC) card with a compact form factor, suitable for multichannel timing instruments or for integration into more complex systems. The TDC Card provides 10 ps timing resolution over the whole measurement range, which is selectable from 160 ns up to 10 μs, reaching 21 ps rms precision, 1.25% LSB rms differential nonlinearity, up to 3 Mconversion/s with 400 mW power consumption. The I/O edge card connector provides timing data readout through either a parallel bus or a 100 MHz serial interface and further measurement information like input signal rate and valid conversion rate (typically useful for time-correlated single-photon counting application) through an independent serial link

Multichannel low power time-to-digital converter card with 21 ps precision and full scale range up to 10 μs

Energy Technology Data Exchange (ETDEWEB)

Tamborini, D., E-mail: davide.tamborini@polimi.it; Portaluppi, D.; Villa, F.; Tosi, A. [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Tisa, S. [Micro Photon Devices, via Stradivari 4, 39100 Bolzano (Italy)

2014-11-15

We present a Time-to-Digital Converter (TDC) card with a compact form factor, suitable for multichannel timing instruments or for integration into more complex systems. The TDC Card provides 10 ps timing resolution over the whole measurement range, which is selectable from 160 ns up to 10 μs, reaching 21 ps rms precision, 1.25% LSB rms differential nonlinearity, up to 3 Mconversion/s with 400 mW power consumption. The I/O edge card connector provides timing data readout through either a parallel bus or a 100 MHz serial interface and further measurement information like input signal rate and valid conversion rate (typically useful for time-correlated single-photon counting application) through an independent serial link.

Multichannel low power time-to-digital converter card with 21 ps precision and full scale range up to 10 μs.

Science.gov (United States)

Tamborini, D; Portaluppi, D; Villa, F; Tisa, S; Tosi, A

2014-11-01

We present a Time-to-Digital Converter (TDC) card with a compact form factor, suitable for multichannel timing instruments or for integration into more complex systems. The TDC Card provides 10 ps timing resolution over the whole measurement range, which is selectable from 160 ns up to 10 μs, reaching 21 ps rms precision, 1.25% LSB rms differential nonlinearity, up to 3 Mconversion/s with 400 mW power consumption. The I/O edge card connector provides timing data readout through either a parallel bus or a 100 MHz serial interface and further measurement information like input signal rate and valid conversion rate (typically useful for time-correlated single-photon counting application) through an independent serial link.

Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC waveform digitizer

Energy Technology Data Exchange (ETDEWEB)

Breton, D. [CNRS/IN2P3/LAL Orsay, Université Paris-Saclay, F-91898 Orsay (France); De Cacqueray, V.; Delagnes, E. [IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Grabas, H. [Santa Cruz Institute for Particle Physics UC Santa Cruz, CA 95064 (United States); Maalmi, J. [CNRS/IN2P3/LAL Orsay, Université Paris-Saclay, F-91898 Orsay (France); Minafra, N. [Dipartimento Interateneo di Fisica di Bari, Bari (Italy); CERN, Geneva (Switzerland); Royon, C. [University of Kansas, Lawrence (United States); Saimpert, M., E-mail: matthias.saimpert@cern.ch [IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France)

2016-11-01

The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to improve time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using pulses generated by a signal generator or by a silicon detector illuminated by a pulsed infrared laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 ps with synthesized signals and 40 ps with silicon detector signals.

Reduced γ–γ time walk to below 50 ps using the multiplexed-start and multiplexed-stop fast-timing technique with LaBr{sub 3}(Ce) detectors

Energy Technology Data Exchange (ETDEWEB)

Régis, J.-M., E-mail: regis@ikp.uni-koeln.de [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Saed-Samii, N., E-mail: nima@ikp.uni-koeln.de [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Rudigier, M. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Ansari, S.; Dannhoff, M.; Esmaylzadeh, A.; Fransen, C.; Gerst, R.-B.; Jolie, J.; Karayonchev, V.; Müller-Gatermann, C.; Stegemann, S. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany)

2016-07-01

The electronic γ–γ fast-timing technique using arrays consisting of many LaBr{sub 3}(Ce) detectors is a powerful method to determine lifetimes of nuclear excited states with a lower limit of about 5 ps. This method requires the determination of the energy-dependent time walk of the zero time which is represented by the centroid of a prompt γ–γ time distribution. The full-energy peak versus full-energy peak prompt response difference which represents the linearly combined mean γ–γ time walk of a fast-timing array consisting of 8 LaBr{sub 3}(Ce) detectors was measured using a standard {sup 152}Eu γ-ray source for the energy region of 40–1408 keV. The data were acquired using a “multiplexed-start and multiplexed-stop” analogue electronics circuitry and analysed by employing the generalized centroid difference method. Concerning the cylindrical 1.5 in.×1.5 in. LaBr{sub 3}(Ce) crystals which are coupled to the Hamamatsu R9779 photomultiplier tubes, the best fast-timing array time resolution of 202(3) ps is obtained for the two prompt γ lines of {sup 60}Co by using the leading-edge timing principle. When using the zero-crossover timing principle the time resolution is degraded by up to 30%, dependent on the energy and the shaping delay time of the constant fraction discriminator model Ortec 935. The smallest γ–γ time walk to below 50 ps is obtained by using a shaping delay time of about 17 ns and an optimum “time-walk adjustment” needed for detector output pulses with amplitudes smaller than 400 mV.

Four-frame gated optical imager with 120-ps resolution

International Nuclear Information System (INIS)

Young, P.E.; Hares, J.D.; Kilkenny, J.D.; Phillion, D.W.; Campbell, E.M.

1988-04-01

In this paper we describe the operation and applications of a framing camera capable of four separate two-dimensional images with each frame having a 120-ps gate width. Fast gating of a single frame is accomplished by using a wafer image intensifier tube in which the cathode is capacitively coupled to an external electrode placed outside of the photocathode of the tube. This electrode is then pulsed relative to the microchannel plate by a narrow (120 ps), high-voltage pulse. Multiple frames are obtained by using multiple gated tubes which share a single bias supply and pulser with relative gate times selected by the cable lengths between the tubes and the pulser. A beamsplitter system has been constructed which produces a separate image for each tube from a single scene. Applications of the framing camera to inertial confinement fusion experiments are discussed

ALTIROC0, a 20 pico-second time resolution ASIC for the ATLAS High Granularity Timing Detector (HGTD)

CERN Document Server

de la Taille, C.; Conforti, S.; Dinaucourt, P.; Martin-Chassard, G.; Seguin-Moreau, N.; Agapopoulou, C.; Makovec, N.; Serin, L.; Simion, S.

2018-01-01

ALTIROC0 is an 8-channel ASIC prototype designed to readout 1x1 or 2x2 mm^2 50 µm thick Low Gain Avalanche Diodes (LGAD) of the ATLAS High Granularity Timing Detector (HGTD). The targeted combined time resolution of the sensor and the readout electronics is 30 ps for one MIP. Each analog channel of the ASIC must exhibit an extremely low jitter to ensure this challenging time resolution, while keeping a low power consumption of 2 mW/channel. A “Time Over Threshold” and a “Constant Fraction Discriminator” architecture are integrated to correct for the time walk. Test bench measurements performed on the ASIC received in April 2017 are presented.

In-depth study of single photon time resolution for the Philips digital silicon photomultiplier

International Nuclear Information System (INIS)

Liu, Z.; Pizzichemi, M.; Ghezzi, A.; Paganoni, M.; Gundacker, S.; Auffray, E.; Lecoq, P.

2016-01-01

The digital silicon photomultiplier (SiPM) has been commercialised by Philips as an innovative technology compared to analog silicon photomultiplier devices. The Philips digital SiPM, has a pair of time to digital converters (TDCs) connected to 12800 single photon avalanche diodes (SPADs). Detailed measurements were performed to understand the low photon time response of the Philips digital SiPM. The single photon time resolution (SPTR) of every single SPAD in a pixel consisting of 3200 SPADs was measured and an average value of 85 ps full width at half maximum (FWHM) was observed. Each SPAD sends the signal to the TDC with different signal propagation time, resulting in a so called trigger network skew. This distribution of the trigger network skew for a pixel (3200 SPADs) has been measured and a variation of 50 ps FWHM was extracted. The SPTR of the whole pixel is the combination of SPAD jitter, trigger network skew, and the SPAD non-uniformity. The SPTR of a complete pixel was 103 ps FWHM at 3.3 V above breakdown voltage. Further, the effect of the crosstalk at a low photon level has been studied, with the two photon time resolution degrading if the events are a combination of detected (true) photons and crosstalk events. Finally, the time response to multiple photons was investigated.

Information extraction from dynamic PS-InSAR time series using machine learning

Science.gov (United States)

van de Kerkhof, B.; Pankratius, V.; Chang, L.; van Swol, R.; Hanssen, R. F.

2017-12-01

Due to the increasing number of SAR satellites, with shorter repeat intervals and higher resolutions, SAR data volumes are exploding. Time series analyses of SAR data, i.e. Persistent Scatterer (PS) InSAR, enable the deformation monitoring of the built environment at an unprecedented scale, with hundreds of scatterers per km2, updated weekly. Potential hazards, e.g. due to failure of aging infrastructure, can be detected at an early stage. Yet, this requires the operational data processing of billions of measurement points, over hundreds of epochs, updating this data set dynamically as new data come in, and testing whether points (start to) behave in an anomalous way. Moreover, the quality of PS-InSAR measurements is ambiguous and heterogeneous, which will yield false positives and false negatives. Such analyses are numerically challenging. Here we extract relevant information from PS-InSAR time series using machine learning algorithms. We cluster (group together) time series with similar behaviour, even though they may not be spatially close, such that the results can be used for further analysis. First we reduce the dimensionality of the dataset in order to be able to cluster the data, since applying clustering techniques on high dimensional datasets often result in unsatisfying results. Our approach is to apply t-distributed Stochastic Neighbor Embedding (t-SNE), a machine learning algorithm for dimensionality reduction of high-dimensional data to a 2D or 3D map, and cluster this result using Density-Based Spatial Clustering of Applications with Noise (DBSCAN). The results show that we are able to detect and cluster time series with similar behaviour, which is the starting point for more extensive analysis into the underlying driving mechanisms. The results of the methods are compared to conventional hypothesis testing as well as a Self-Organising Map (SOM) approach. Hypothesis testing is robust and takes the stochastic nature of the observations into account

A 96-channel, 500 ps resolution TDC board for the BaBar experiment at SLAC

CERN Document Server

Minutoli, S

2000-01-01

A TDC board has been designed and built to complete the readout of the Instrumented Flux Return of the BABAR experiment at the Stanford Linear Accelerator Center. The board has 96 input channels and makes use of 3 general purpose TDC chips designed at CERN, with time resolution up to 500 ps and configurable via a Test Access Port (IEEE standard 1149). Data are stored before readout in a multievent buffer. Communication with BABAR DAQ system is realized through 3 serial lines on the backplane connector. All the logic, including internal registers and the interfaces with the BABAR protocol and the TAP controller, is implemented in two fast FPGAs. The board is designed to work at 59.5 MHz clock frequency. (7 refs).

Factors Influencing Time Resolution of Scintillators and Ways to Improve Them

CERN Document Server

Lecoq, P; Brunner, S; Meyer, T; Auffray, E; Knapitsch, A; Jarron, P

2010-01-01

The renewal of interest in Time of Flight Positron Emission Tomography (TOF-PET), as well as the necessity to precisely tag events in high energy physics (HEP) experiments at future colliders are pushing for an optimization of all factors affecting the time resolution of the whole acquisition chain comprising the crystal, the photo detector, and the electronics. The time resolution of a scintillator-based detection system is determined by the rate of photo electrons at the detection threshold, which depends on the time distribution of photons being converted in the photo detector. The possibility to achieve time resolution of about 100 ps Full Width at Half Maximum (FWHM) requires an optimization of the light production in the scintillator, the light transport and its transfer from the scintillator to the photo detector. In order to maximize the light yield, and in particular the density of photons in the first nanosecond, while minimizing the rise time and decay time, particular attention must be paid to the...

High resolution time-of-flight (TOF) detector for particle identification

Energy Technology Data Exchange (ETDEWEB)

Boehm, Merlin; Lehmann, Albert; Pfaffinger, Markus; Uhlig, Fred [Physikalisches Institut, Universitaet Erlangen-Nuernberg (Germany); Collaboration: PANDA-Collaboration

2016-07-01

Several prototype tests were performed with the PANDA DIRC detectors at the CERN T9 beam line. A mixed hadron beam with pions, kaons and protons was used at momenta from 2 to 10 GeV/c. For these tests a good particle identification was mandatory. We report about a high resolution TOF detector built especially for this purpose. It consists of two stations each consisting of a Cherenkov radiator read out by a Microchannel-Plate Photomultiplier (MCP-PMT) and a Scintillating Tile (SciTil) counter read out by silicon photomultipliers (SiPMs). With a flight path of 29 m a pion/kaon separation up to 5 GeV/c and a pion/proton separation up to 10 GeV/c was obtained. From the TOF resolutions of different counter combinations the time resolution (sigma) of the individual MCP-PMTs and SciTils was determined. The best counter reached a time resolution of 50 ps.

Measurement of the time resolution of small SiPM-based scintillation counters

Science.gov (United States)

Kravchenko, E. A.; Porosev, V. V.; Savinov, G. A.

2017-12-01

In this research, we evaluated the timing resolution of SiPM-based scintillation detector on a 1-GeV electron beam "extracted" from VEPP-4M. We tested small scintillation crystals of pure CsI, YAP, LYSO, and LFS-3 with HAMAMATSU S10362-33-025C and S13360-3050CS. The CsI scintillator together with HAMAMATSU S13360-3050CS demonstrated the best results. Nevertheless, the achieved time resolution of ~80 ps (RMS) relates mainly to the photodetector itself. It makes the silicon photomultiplier an attractive candidate to replace other devices in applications where sub-nanosecond accuracy is required.

High frequency, high time resolution time-to-digital converter employing passive resonating circuits.

Science.gov (United States)

Ripamonti, Giancarlo; Abba, Andrea; Geraci, Angelo

2010-05-01

A method for measuring time intervals accurate to the picosecond range is based on phase measurements of oscillating waveforms synchronous with their beginning and/or end. The oscillation is generated by triggering an LC resonant circuit, whose capacitance is precharged. By using high Q resonators and a final active quenching of the oscillation, it is possible to conjugate high time resolution and a small measurement time, which allows a high measurement rate. Methods for fast analysis of the data are considered and discussed with reference to computing resource requirements, speed, and accuracy. Experimental tests show the feasibility of the method and a time accuracy better than 4 ps rms. Methods aimed at further reducing hardware resources are finally discussed.

High frequency, high time resolution time-to-digital converter employing passive resonating circuits

International Nuclear Information System (INIS)

Ripamonti, Giancarlo; Abba, Andrea; Geraci, Angelo

2010-01-01

A method for measuring time intervals accurate to the picosecond range is based on phase measurements of oscillating waveforms synchronous with their beginning and/or end. The oscillation is generated by triggering an LC resonant circuit, whose capacitance is precharged. By using high Q resonators and a final active quenching of the oscillation, it is possible to conjugate high time resolution and a small measurement time, which allows a high measurement rate. Methods for fast analysis of the data are considered and discussed with reference to computing resource requirements, speed, and accuracy. Experimental tests show the feasibility of the method and a time accuracy better than 4 ps rms. Methods aimed at further reducing hardware resources are finally discussed.

Cross-talk of a multi-anode PMT and attainment of a σ∼10ps TOF counter

International Nuclear Information System (INIS)

Enari, Y.; Hayasaka, K.; Hokuue, T.; Inami, K.; Ohshima, T.; Sato, N.; Akatsu, M.; Kawakami, S.; Miyabayashi, Y.; Tokuda, H.; Yanase, H.; Shimoi, H.; Fujimori, T.

2005-01-01

We extensively studied a cross-talk phenomenon that seriously deteriorates the high time-resolution of a multi-anode 16-channel linear array photo-multiplier tube (PMT); the dynode structures were modified to eliminate the cross-talk effect and to recover a time resolution of σ=70-80ps for single photons. The use of 16 anode signals of the modified PMT enabled us to attain σ=12ps for a small TOF counter of Cherenkov radiation

The LLL compact 10-ps streak camera

International Nuclear Information System (INIS)

Thomas, S.W.; Houghton, J.W.; Tripp, G.R.; Coleman, L.W.

1975-01-01

The 10-ps streak camera has been redesigned to simplify its operation, reduce manufacturing costs, and improve its appearance. The electronics have been simplified, a film indexer added, and a contacted slit has been evaluated. Data support a 10-ps resolution. (author)

A high resolution, low power time-of-flight system for the space experiment AMS

International Nuclear Information System (INIS)

Alvisi, D.; Anselmo, F.; Baldini, L.; Bari, G.; Basile, M.; Bellagamba, L.; Bruni, A.; Bruni, G.; Boscherini, D.; Casadei, D.; Cara Romeo, G.; Castellini, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Polini, A.; Recupero, S.; Sartorelli, G.; Williams, C.; Zichichi, A.

1999-01-01

The system of plastic scintillator counters for the AMS experiment is described. The main characteristics of the detector are: (a) large sensitive area (four 1.6 m 2 planes) with small dead space; (b) low-power consumption (150 W for the power and the read-out electronics of 336 PMs); (c) 120 ps time resolution

submitter Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET

CERN Document Server

Gundacker, Stefan; Pauwels, Kristof; Lecoq, Paul

2016-01-01

The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time (${{\\tau}_{d}}$ ) and the number of photons detected (${{n}^{\\prime}}$ ), i.e. $CTR\\propto \\sqrt{{{\\tau}_{d}}/{{n}^{\\prime}}}$ . However, it is still an open question to what extent the scintillation rise time (${{\\tau}_{r}}$ ) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, promp...

How Photonic Crystals Can Improve the Timing Resolution of Scintillators

CERN Document Server

Lecoq, P; Knapitsch, A

2013-01-01

Photonic crystals (PhCs) and quantum optics phenomena open interesting perspectives to enhance the light extraction from scintillating me dia with high refractive indices as demonstrated by our previous work. By doing so, they also in fl uence the timing resolution of scintillators by improving the photostatistics. The present cont ribution will demonstrate that they are actually doing much more. Indeed, photonic crystals, if properly designed, allow the extr action of fast light propagation modes in the crystal with higher efficiency, therefore contributing to increasing the density of photons in the early phase of the light pulse. This is of particular interest to tag events at future high-energy physics colliders, such as CLIC, with a bunch-crossing rate of 2 GHz, as well as for a new generation of time-of-flight positron emission tomographs (TOFPET) aiming at a coincidence timing resolution of 100 ps FWHM. At this level of precision, good control of the light propagation modes is crucial if we consid...

Test of high time resolution MRPC with different readout modes for the BESIII upgrade

Energy Technology Data Exchange (ETDEWEB)

Yang, S. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Sun, Y.J., E-mail: sunday@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Li, C., E-mail: licheng@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Heng, Y.K.; Qian, S. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Chen, H.F.; Chen, T.X. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Dai, H.L. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Fan, H.H.; Liu, S.B. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Liu, S.D.; Jiang, X.S. [Institute of High Energy Physics, Chinese Academy of Sciences(IHEP), Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China); Shao, M.; Tang, Z.B.; Zhang, H.; Zhao, Z.G. [Department of Modern Physics, University of Science and Technology of China(USTC), Hefei 230026 (China); State Key Laboratory of Particle Detection and Electronics(USTC-IHEP) (China)

2014-11-01

In order to further enhance the particle identification capability of the Beijing Spectrometer (BESIII), it is proposed to upgrade the current end-cap time-of-flight (eTOF) detector with multi-gap resistive plate chamber (MRPC). The prototypes, together with the front end electronics (FEE) and time digitizer (TDIG) module have been tested at the E3 line of Beijing Electron Positron Collider (BEPCII) to study the difference between the single and double-end readout MRPC designs. The time resolutions (sigma) of the single-end readout MRPC are 47/53 ps obtained by 600 MeV/c proton/pion beam, while that of the double-end readout MRPC is 40 ps (proton beam). The efficiencies of three MRPC modules tested by both proton and pion beam are better than 98%. For the double-end readout MRPC, no incident position dependence is observed.

Radio frequency phototube and optical clock: High resolution, high rate and highly stable single photon timing technique

Energy Technology Data Exchange (ETDEWEB)

Margaryan, Amur

2011-10-01

A new timing technique for single photons based on the radio frequency phototube and optical clock or femtosecond optical frequency comb generator is proposed. The technique has a 20 ps resolution for single photons, is capable of operating with MHz frequencies and achieving 10 fs instability level.

HiPS - Hierarchical Progressive Survey Version 1.0

Science.gov (United States)

Fernique, Pierre; Allen, Mark; Boch, Thomas; Donaldson, Tom; Durand, Daniel; Ebisawa, Ken; Michel, Laurent; Salgado, Jesus; Stoehr, Felix; Fernique, Pierre

2017-05-01

This document presents HiPS, a hierarchical scheme for the description, storage and access of sky survey data. The system is based on hierarchical tiling of sky regions at finer and finer spatial resolution which facilitates a progressive view of a survey, and supports multi-resolution zooming and panning. HiPS uses the HEALPix tessellation of the sky as the basis for the scheme and is implemented as a simple file structure with a direct indexing scheme that leads to practical implementations.

A 45 ps time digitizer with a two-phase clock and dual-edge two-stage interpolation in a field programmable gate array device

Science.gov (United States)

Szplet, R.; Kalisz, J.; Jachna, Z.

2009-02-01

We present a time digitizer having 45 ps resolution, integrated in a field programmable gate array (FPGA) device. The time interval measurement is based on the two-stage interpolation method. A dual-edge two-phase interpolator is driven by the on-chip synthesized 250 MHz clock with precise phase adjustment. An improved dual-edge double synchronizer was developed to control the main counter. The nonlinearity of the digitizer's transfer characteristic is identified and utilized by the dedicated hardware code processor for the on-the-fly correction of the output data. Application of presented ideas has resulted in the measurement uncertainty of the digitizer below 70 ps RMS over the time interval ranging from 0 to 1 s. The use of the two-stage interpolation and a fast FIFO memory has allowed us to obtain the maximum measurement rate of five million measurements per second.

A 45 ps time digitizer with a two-phase clock and dual-edge two-stage interpolation in a field programmable gate array device

International Nuclear Information System (INIS)

Szplet, R; Kalisz, J; Jachna, Z

2009-01-01

We present a time digitizer having 45 ps resolution, integrated in a field programmable gate array (FPGA) device. The time interval measurement is based on the two-stage interpolation method. A dual-edge two-phase interpolator is driven by the on-chip synthesized 250 MHz clock with precise phase adjustment. An improved dual-edge double synchronizer was developed to control the main counter. The nonlinearity of the digitizer's transfer characteristic is identified and utilized by the dedicated hardware code processor for the on-the-fly correction of the output data. Application of presented ideas has resulted in the measurement uncertainty of the digitizer below 70 ps RMS over the time interval ranging from 0 to 1 s. The use of the two-stage interpolation and a fast FIFO memory has allowed us to obtain the maximum measurement rate of five million measurements per second

Development of a 64-channel 100 ps TDC module

International Nuclear Information System (INIS)

Liu Xiaohua; An Qi; Liu Shubin; Su Hong; Zhan Wenlong

2009-01-01

Multi-wire drift chamber at external target experiment in HIRFL-CSR measures drift time of charged particles to obtain the track information. A 64-channel TDC module hosting high density connectors and high performance TDC chips (HPTDC) are used to perform the time digitization. Data of the module is transferred to computer through PXI bus. The test results show that a 100 ps resolution has been achieved. (authors)

Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC WTDC

CERN Document Server

Breton, Dominique

2016-11-01

The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter (TDC) and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to maximize time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using Gaussian signals generated by a signal generator or by silicon detectors pulsed with an infra-red laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 (40) ps with synthesized (silicon detector) signals.

Test beam studies of the light yield, time and coordinate resolutions of scintillator strips with WLS fibers and SiPM readout

Energy Technology Data Exchange (ETDEWEB)

Denisov, Dmitri [Fermilab, Batavia IL (United States); Evdokimov, Valery [Institute for High Energy Physics, Protvino (Russian Federation); Lukić, Strahinja; Ujić, Predrag [Vinča Institute, University of Belgrade (Serbia)

2017-03-11

Prototype scintilator+WLS strips with SiPM readout for large muon detection systems were tested in the muon beam of the Fermilab Test Beam Facility. Light yield of up to 137 photoelectrons per muon per strip has been observed , as well as time resolution of 330 ps and position resolution along the strip of 5.4 cm.

High resolution distributed time-to-digital converter (TDC) in a White Rabbit network

International Nuclear Information System (INIS)

Pan, Weibin; Gong, Guanghua; Du, Qiang; Li, Hongming; Li, Jianmin

2014-01-01

The Large High Altitude Air Shower Observatory (LHAASO) project consists of a complex detector array with over 6000 detector nodes spreading over 1.2 km 2 areas. The arrival times of shower particles are captured by time-to-digital converters (TDCs) in the detectors' frontend electronics, the arrival direction of the high energy cosmic ray are then to be reconstructed from the space-time information of all detector nodes. To guarantee the angular resolution of 0.5°, a time synchronization of 500 ps (RMS) accuracy and 100 ps precision must be achieved among all TDC nodes. A technology enhancing Gigabit Ethernet, called the White Rabbit (WR), has shown the capability of delivering sub-nanosecond accuracy and picoseconds precision of synchronization over the standard data packet transfer. In this paper we demonstrate a distributed TDC prototype system combining the FPGA based TDC and the WR technology. With the time synchronization and data transfer services from a compact WR node, separate FPGA-TDC nodes can be combined to provide uniform time measurement information for correlated events. The design detail and test performance will be described in the paper

High resolution distributed time-to-digital converter (TDC) in a White Rabbit network

Energy Technology Data Exchange (ETDEWEB)

Pan, Weibin, E-mail: pwb.thu@gmail.com; Gong, Guanghua; Du, Qiang; Li, Hongming; Li, Jianmin

2014-02-21

The Large High Altitude Air Shower Observatory (LHAASO) project consists of a complex detector array with over 6000 detector nodes spreading over 1.2 km{sup 2} areas. The arrival times of shower particles are captured by time-to-digital converters (TDCs) in the detectors' frontend electronics, the arrival direction of the high energy cosmic ray are then to be reconstructed from the space-time information of all detector nodes. To guarantee the angular resolution of 0.5°, a time synchronization of 500 ps (RMS) accuracy and 100 ps precision must be achieved among all TDC nodes. A technology enhancing Gigabit Ethernet, called the White Rabbit (WR), has shown the capability of delivering sub-nanosecond accuracy and picoseconds precision of synchronization over the standard data packet transfer. In this paper we demonstrate a distributed TDC prototype system combining the FPGA based TDC and the WR technology. With the time synchronization and data transfer services from a compact WR node, separate FPGA-TDC nodes can be combined to provide uniform time measurement information for correlated events. The design detail and test performance will be described in the paper.

Walk-free fast timing for a heavy-ion time-of-flight telescope

International Nuclear Information System (INIS)

Sanderson, N.E.; Fulton, B.R.; England, J.B.A.

1976-01-01

An intrinsic time resolution of 68 ps between two surface barrier detectors has been achieved. The timing walk associated with pulse height variations is reduced by means of computer correction to below 30 ps. (Auth.)

Time resolution of Burle 85001 micro-channel plate photo-multipliers in comparison with Hamamatsu R2083

Energy Technology Data Exchange (ETDEWEB)

V. Baturin; V. Burkert; W. Kim; S. Majewsky; D. Nekrasov; K. Park; V. Popov; E. S. Smith; D. Son; S. S. Stepanyan; C. Zorn

2005-06-01

The CLAS detector will require improvements in its particle identification system to take advantage of the higher energies provided by the Jefferson Laboratory accelerator upgrade to 12 GeV. To this end, we have studied the timing characteristics of the micro-channel plate photo-multiplier 85001 from Burle, which can be operated in a high magnetic field environment. For reference and comparison, measurements were also made using the standard PMT R2083 from Hamamatsu using two timing methods. The cosmic ray method, which utilizes three identical scintillating counters 2cm x 3cm x 50cm with PMs at the ends, yields 59.1(0.7)ps. The location method of particles from radiative source with known coordinates has been used to compare timing resolutions of R2083 and Burle-85001. This ''coordinate method'' requires only one counter instrumented with two PMs and it yields 59.5(0.7)ps. For the micro-channel plate photomultiplier from Burle with an external amplification of 10 to the signals, the co ordinate method yields 130(4)ps. This method also makes it possible to estimate the number of primary photo-electrons.

100-ps framing-camera tube

International Nuclear Information System (INIS)

Kalibjian, R.

1978-01-01

The optoelectronic framing-camera tube described is capable of recording two-dimensional image frames with high spatial resolution in the <100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits. The resulting dissected electron line images from the slits are restored into framed images by a restorer deflector operating synchronously with the dissector deflector. The number of framed images on the tube's viewing screen equals the number of dissecting slits in the tube. Performance has been demonstrated in a prototype tube by recording 135-ps-duration framed images of 2.5-mm patterns at the cathode. The limitation in the framing speed is in the external drivers for the deflectors and not in the tube design characteristics. Faster frame speeds in the <100-ps range can be obtained by use of faster deflection drivers

A Systematic Study to Optimize SiPM Photo-Detectors for Highest Time Resolution in PET

CERN Document Server

Gundacker, S.; Frisch, B.; Hillemanns, H.; Jarron, P.; Meyer, T.; Pauwels, K.; Lecoq, P.

2012-01-01

We report on a systematic study of time resolution made with three different commercial silicon photomultipliers (SiPMs) (Hamamatsu MPPC S10931-025P, S10931-050P, and S10931-100P) and two LSO scintillating crystals. This study aimed to determine the optimum detector conditions for highest time resolution in a prospective time-of-flight positron emission tomography (TOF-PET) system. Measurements were based on the time over threshold method in a coincidence setup using the ultrafast amplifier-discriminator NINO and a fast oscilloscope. Our tests with the three SiPMs of the same area but of different SPAD sizes and fill factors led to best results with the Hamamatsu type of 50×50×μm2 single-pixel size. For this type of SiPM and under realistic geometrical PET scanner conditions, i.e., with 2×2×10×mm3 LSO crystals, a coincidence time resolution of 220 ±4 ps FWHM could be achieved. The results are interpreted in terms of SiPM photon detection efficiency (PDE), dark noise, and photon yield.

A comprehensive & systematic study of coincidence time resolution and light yield using scintillators of different size, wrapping and doping

CERN Document Server

Auffray, E.; Geraci, F.; Ghezzi, A.; Gundacker, S.; Hillemanns, H.; Jarron, P.; Meyer, T.; Paganoni, M.; Pauwels, K.; Pizzichemi, M.; Lecoq, P.

2011-01-01

Over the last years interest in using time-of-flight-based Positron Emission Tomography (TOF-PET) systems has significantly increased. High time resolution in such PET systems is a powerful tool to improve signal to noise ratio and therefore to allow smaller exposure rates for patients as well as faster image reconstruction. Improvement in coincidence time resolution (CTR) in PET systems to the level of 200ps FWHM requires the optimization of all parameters in the photon detection chain influencing the time resolution: crystal, photodetector and readout electronics. After reviewing the factors influencing the time resolution of scintillators, we will present in this paper the light yield and CTR obtained for different scintillator types (LSO:Ce, LYSO:Ce, LGSO:Ce, LSO:Ce:0.4Ca, LuAG:Ce, LuAG:Pr) with different cross-sections, lengths and reflectors. Whereas light yield measurements were made with a classical PMT, all CTR tests were performed with Hamamatsu-MPPCs or SiPMs S10931-050P. The CTR measurements were ...

Detectors and Concepts for sub-100 ps timing with gaseous detectors

CERN Document Server

Gonzalez-Diaz, D.

2017-01-01

We give a short compendium of the main ongoing detectors and concepts capable of performing accurate sub-100 ps timing at high particle fluxes and on large areas, through technologies based on gaseous media. We briefly discuss the state-of-the-art, technological limitations and prospects, and a new bizarre idea.

A microchannel plate X-ray multiplier with rising-time less than 170 ps

International Nuclear Information System (INIS)

Zhao Shicheng; Ouyang Bin

1987-01-01

The time reponse of a microchannel plate X-ray multiplier has been improved considerably by using a coupling construction of coaxial tapers. The experimental calibration results with laser plasma X-ray source show that the rising-time of the multiplier is less than 170 ps

Timing in a FLASH

Science.gov (United States)

Hoek, M.; Cardinali, M.; Corell, O.; Dickescheid, M.; Ferretti B., M. I.; Lauth, W.; Schlimme, B. S.; Sfienti, C.; Thiel, M.

2017-12-01

A prototype detector, called FLASH (Fast Light Acquiring Start Hodoscope), was built to provide precise Time-of-Flight (TOF) measurements and reference timestamps for detector setups at external beam lines. Radiator bars, made of synthetic fused silica, were coupled to a fast MCP-PMT with 64 channels and read out with custom electronics using Time-over-Threshold (TOT) for signal characterization. The TRB3 system, a high-precision TDC implemented in an FPGA, was used as data acquisition system. The performance of a system consisting of two FLASH units was investigated at a dedicated test experiment at the Mainz Microtron (MAMI) accelerator using its 855 MeV electron beam. The TOT measurement enabled time walk corrections and an overall TOF resolution of ∼70 ps could be achieved which translates into a resolution of ∼50 ps per FLASH unit. The intrinsic resolution of the frontend electronics including the TDC was measured to be less than 25 ps.

Testing the YerPhI Transimpedance Preamplifier with PPC by the T11 PS Beam

CERN Document Server

Parlakian, L K; CERN. Geneva; Martmianov, A N

1997-01-01

We report on the test of the preamplifier, described in [1], by the 3 GeV/c positive particle T11 beam of PS/CERN. We have measured the amplitude and time of flight spectrum, the time resolution and detection efficiency. The preamplifier has shown a stable work and hardness to the chamber discharge. The test results are presented.

The Proton Beams for the New Time-of-Flight Neutron Facility at the CERN-PS

CERN Document Server

Cappi, R; Métral, G

2000-01-01

The experimental determination of neutron cross sections in fission and capture reactions as a function of the neutron energy is of primary importance in nuclear physics. Recent developments at CERN and elsewhere have shown that many fields of research and development, such as the design of Accelerator-Driven Systems (ADS) for nuclear waste incineration, nuclear astrophysics, fundamental nuclear physics, dosimetry for radiological protection and therapy, would benefit from a better knowledge of neutron cross sections. A neutron facility at the CERN-PS has been proposed with the aim of carrying out a systematic and high resolution study of neutron cross sections through Time-Of-Flight (n-TOF) measurement. The facility requires a high intensity proton beam (about 0.7x1013 particles/bunch) distributed in a short bunch (about 25 ns total length) to produce the neutrons by means of a spallation process in a lead target. To achieve these characteristics, a number of complex beam gymnastics have to be performed. All...

Properties of a six-gap timing resistive plate chamber with strip readout

International Nuclear Information System (INIS)

Ammosov, V.V.; Gapienko, V.A.; Semak, A.A.; Sviridov, Yu.M.; Zaets, V.G.; Gavrishchuk, O.P.; Kuz'min, N.A.; Sychkov, S.Ya.; Usenko, E.A.; Yukaev, A.I.

2009-01-01

Six-gap glass timing resistive plate chamber with strip readout was tested using IHEP U-70 PS test beam. The time resolution of ∼ 45 ps at efficiency larger than 98% was achieved. Position resolution along strip was estimated to be ∼1 cm

Gain and time resolution of 45 μm thin Low Gain Avalanche Detectors before and after irradiation up to a fluence of 1015 neq/cm2

International Nuclear Information System (INIS)

Lange, J.; Cavallaro, E.; Förster, F.; Grinstein, S.; Carulla, M.; Flores, D.; Hidalgo, S.; Merlos, A.; Pellegrini, G.; Quirion, D.; Chytka, L.; Komarek, T.; Nozka, L.; Davis, P.M.; Kramberger, G.; Mandić, I.; Sykora, T.

2017-01-01

Low Gain Avalanche Detectors (LGADs) are silicon sensors with a built-in charge multiplication layer providing a gain of typically 10 to 50. Due to the combination of high signal-to-noise ratio and short rise time, thin LGADs provide good time resolutions. LGADs with an active thickness of about 45 μm were produced at CNM Barcelona. Their gains and time resolutions were studied in beam tests for two different multiplication layer implantation doses, as well as before and after irradiation with neutrons up to 10 15 n eq /cm 2 . The gain showed the expected decrease at a fixed voltage for a lower initial implantation dose, as well as for a higher fluence due to effective acceptor removal in the multiplication layer. Time resolutions below 30 ps were obtained at the highest applied voltages for both implantation doses before irradiation. Also after an intermediate fluence of 3×10 14 n eq /cm 2 , similar values were measured since a higher applicable reverse bias voltage could recover most of the pre-irradiation gain. At 10 15 n eq /cm 2 , the time resolution at the maximum applicable voltage of 620 V during the beam test was measured to be 57 ps since the voltage stability was not good enough to compensate for the gain layer loss. The time resolutions were found to follow approximately a universal function of gain for all implantation doses and fluences.

The time-of-flight TOFW detector of the HARP experiment: construction and performance

International Nuclear Information System (INIS)

Baldo-Ceolin, M.; Barichello, G.; Bobisut, F.; Bonesini, M.; De Min, A.; Ferri, A.F.; Gibin, D.; Guglielmi, A.; Laveder, M.; Menegolli, A.; Mezzetto, M.; Paganoni, M.; Paleari, F.; Pepato, A.; Tonazzo, A.; Vascon, M.

2004-01-01

The construction and performance of a large area scintillator-based time-of-flight detector for the HARP experiment at CERN are reported. An intrinsic counter time resolution of ∼160 ps was achieved. The precision on the time calibration and monitoring of the detector was maintained at better than 100 ps by using dedicated cosmic rays runs, a fast laser-based system and calibrations with beam particles. The detector was operated on the T9 PS beamline during 2001 and 2002. A time-of-flight resolution of ∼200 ps was obtained, providing π/p discrimination at more than 3σ up to 4.0 GeV/c momentum

On the crystallization behavior of syndiotactic-b-atactic polystyrene stereodiblock copolymers, atactic/syndiotactic polystyrene blends, and aPS/sPS blends modified with sPS-b-aPS

Energy Technology Data Exchange (ETDEWEB)

Annunziata, Liana, E-mail: liana.annunziatta@univ-rennes1.fr [Organométalliques et Catalyse, UMR 6226 Sciences Chimiques CNRS, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France); Monasse, Bernard, E-mail: bernard.monasse@mines-paristech.fr [Mines-ParisTech, CEMEF, Centre de Mise en Forme des Matériaux, UMR CNRS 7635, Sophia Antipolis (France); Rizzo, Paola; Guerra, Gaetano [Dipartimento di Chimica e Biologia, Università degli studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano, SA (Italy); Duc, Michel [Total Petrochemicals Research Feluy, Zone Industrielle Feluy C, B-7181 Seneffe (Belgium); Carpentier, Jean-François, E-mail: jean-francois.carpentier@univ-rennes1.fr [Organométalliques et Catalyse, UMR 6226 Sciences Chimiques CNRS, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex (France)

2013-09-16

Crystallization and morphological features of syndiotactic-b-atactic polystyrene stereodiblock copolymers (sPS-b-aPS), atactic/syndiotactic polystyrene blends (aPS/sPS), and aPS/sPS blends modified with sPS-b-aPS, with different compositions in aPS and sPS, have been investigated using differential scanning calorimetry (DSC), polarized light optical microscopy (POM) and wide angle X-ray diffraction (WAXRD) techniques. For comparative purposes, the properties of parent pristine sPS samples were also studied. WAXRD analyses revealed for all the samples, independently from their composition (aPS/sPS ratio) and structure (blends, block copolymers, blends modified with block copolymers), the same polymorphic β form of sPS. The molecular weight of aPS and sPS showed opposite effects on the crystallization of 50:50 aPS/sPS blends: the lower the molecular weight of aPS, the slower the crystallization while the lower the molecular weight of sPS, the faster the crystallization. DSC studies performed under both isothermal and non-isothermal conditions, independently confirmed by POM studies, led to a clear trend for the crystallization rate at a given sPS/aPS ratio (ca. 50:50 and 20:80): sPS homopolymers > sPS-b-aPS block copolymers ∼sPS/aPS blends modified with sPS-b-aPS copolymers > sPS/aPS blends. Interestingly, sPS-b-aPS block copolymers not only crystallized faster than blends, but also affected positively the crystallization behavior of blends. At 50:50 sPS/aPS ratio, blends (Blend-2), block copolymers (Cop-1) and blends modified with block copolymers (Blend-2-mod) crystallized via spherulitic crystalline growth controlled by an interfacial process. In all cases, an instantaneous nucleation was observed. The density of nuclei in block copolymers (160,000−190,000 nuclei mm{sup −3}) was always higher than that in blends and modified blends (30,000−60,000 nuclei mm{sup −3}), even for quite different sPS/aPS ratio. At 20:80 sPS/aPS ratio, the block copolymers

High-Resolution Digital-to-Time Converter Implemented in an FPGA Chip

Directory of Open Access Journals (Sweden)

Hai Wang

2017-01-01

Full Text Available This paper presents the design and implementation of a new digital-to-time converter (DTC. The obtained resolution is 1.02 ps, and the dynamic range is about 590 ns. The experimental results indicate that the measured differential nonlinearity (DNL and integral nonlinearity (INL are −0.17~+0.13 LSB and −0.35~+0.62 LSB, respectively. This DTC builds coarse and fine Vernier delay lines constructed by programmable delay lines (PDLs to ensure high performance delay. Benefited by the close-loop feedback mechanism of the PDLs’ control module, the presented DTC has excellent voltage and temperature stability. What is more, the proposed DTC can be implemented in a single field programmable gate array (FPGA chip.

High resolution neutron spectroscopy for helium isotopes

International Nuclear Information System (INIS)

Abdel-Wahab, M.S.; Klages, H.O.; Schmalz, G.; Haesner, B.H.; Kecskemeti, J.; Schwarz, P.; Wilczynski, J.

1992-01-01

A high resolution fast neutron time-of-flight spectrometer is described, neutron time-of-flight spectra are taken using a specially designed TDC in connection to an on-line computer. The high time-of-flight resolution of 5 ps/m enabled the study of the total cross section of 4 He for neutrons near the 3/2 + resonance in the 5 He nucleus. The resonance parameters were determined by a single level Breit-Winger fit to the data. (orig.)

Results from the NA62 Gigatracker Prototype: A Low-Mass and sub-ns Time Resolution Silicon Pixel Detector

Science.gov (United States)

Fiorini, M.; Rinella, G. Aglieri; Carassiti, V.; Ceccucci, A.; Gil, E. Cortina; Ramusino, A. Cotta; Dellacasa, G.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Mapelli, A.; Martin, E.; Mazza, G.; Morel, M.; Noy, M.; Nuessle, G.; Petagna, P.; Petrucci, F.; Perktold, L.; Riedler, P.; Rivetti, A.; Statera, M.; Velghe, B.

The Gigatracker (GTK) is a hybrid silicon pixel detector developed for NA62, the experiment aimed at studying ultra-rare kaon decays at the CERN SPS. Three GTK stations will provide precise momentum and angular measurements on every track of the high intensity NA62 hadron beam with a time-tagging resolution of 150 ps. Multiple scattering and hadronic interactions of beam particles in the GTK have to be minimized to keep background events at acceptable levels, hence the total material budget is fixed to 0.5% X0 per station. In addition the calculated fluence for 100 days of running is 2×1014 1 MeV neq/cm2, comparable to the one expected for the inner trackers of LHC detectors in 10 years of operation. These requirements pose challenges for the development of an efficient and low-mass cooling system, to be operated in vacuum, and on the thinning of read-out chips to 100 μm or less. The most challenging requirement is represented by the time resolution, which can be achieved by carefully compensating for the discriminator time-walk. For this purpose, two complementary read-out architectures have been designed and produced as small-scale prototypes: the first is based on the use of a Time-over-Threshold circuit followed by a TDC shared by a group of pixels, while the other uses a constant-fraction discriminator followed by an on-pixel TDC. The readout pixel ASICs are produced in 130 nm IBM CMOS technology and bump-bonded to 200 μm thick silicon sensors. The Gigatracker detector system is described with particular emphasis on recent experimental results obtained from laboratory and beam tests of prototype bump-bonded assemblies, which show a time resolution of less than 200 ps for single hits.

A Time-Walk Correction Method for PET Detectors Based on Leading Edge Discriminators.

Science.gov (United States)

Du, Junwei; Schmall, Jeffrey P; Judenhofer, Martin S; Di, Kun; Yang, Yongfeng; Cherry, Simon R

2017-09-01

The leading edge timing pick-off technique is the simplest timing extraction method for PET detectors. Due to the inherent time-walk of the leading edge technique, corrections should be made to improve timing resolution, especially for time-of-flight PET. Time-walk correction can be done by utilizing the relationship between the threshold crossing time and the event energy on an event by event basis. In this paper, a time-walk correction method is proposed and evaluated using timing information from two identical detectors both using leading edge discriminators. This differs from other techniques that use an external dedicated reference detector, such as a fast PMT-based detector using constant fraction techniques to pick-off timing information. In our proposed method, one detector was used as reference detector to correct the time-walk of the other detector. Time-walk in the reference detector was minimized by using events within a small energy window (508.5 - 513.5 keV). To validate this method, a coincidence detector pair was assembled using two SensL MicroFB SiPMs and two 2.5 mm × 2.5 mm × 20 mm polished LYSO crystals. Coincidence timing resolutions using different time pick-off techniques were obtained at a bias voltage of 27.5 V and a fixed temperature of 20 °C. The coincidence timing resolution without time-walk correction were 389.0 ± 12.0 ps (425 -650 keV energy window) and 670.2 ± 16.2 ps (250-750 keV energy window). The timing resolution with time-walk correction improved to 367.3 ± 0.5 ps (425 - 650 keV) and 413.7 ± 0.9 ps (250 - 750 keV). For comparison, timing resolutions were 442.8 ± 12.8 ps (425 - 650 keV) and 476.0 ± 13.0 ps (250 - 750 keV) using constant fraction techniques, and 367.3 ± 0.4 ps (425 - 650 keV) and 413.4 ± 0.9 ps (250 - 750 keV) using a reference detector based on the constant fraction technique. These results show that the proposed leading edge based time-walk correction method works well. Timing resolution obtained

Sub-picosecond Resolution Time-to-Digital Converter

Energy Technology Data Exchange (ETDEWEB)

Bratov, Vladimir [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States); Katzman, Vladimir [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States); Binkley, Jeb [Advanced Science and Novel Technology Company, Rancho Palos Verdes, CA (United States)

2006-03-30

Time-to-digital converters with sub-picosecond resolutions are needed to satisfy the requirements of time-on-flight measurements of the next generation of high energy and nuclear physics experiments. The converters must be highly integrated, power effective, low cost, and feature plug-and-play capabilities to handle the increasing number of channels (up to hundreds of millions) in future Department of Energy experiments. Current state-off-the-art time-to-digital converter integrated circuits do not have the sufficient degree of integration and flexibility to fulfill all the described requirements. During Phase I, the Advanced Science and Novel Technology Company in cooperation with the nuclear physics division of the Oak Ridge National Laboratory has developed the architecture of a novel time-to-digital converter with multiple channels connected to an external processor through a special interfacing block and synchronized by clock signals generated by an internal phase-locked loop. The critical blocks of the system including signal delay lines and delay-locked loops with proprietary differential delay cells, as well as the required digital code converter and the clock period counter have been designed and simulated using the advanced SiGe120 BiCMOS technological process. The results of investigations demonstrate a possibility to achieve the digitization accuracy within 1ps. ADSANTEC has demonstrated the feasibility of the proposed concept in computer simulations. The proposed system will be a critical component for the next generation of NEP experiments.

Effects of External Digital Elevation Model Inaccuracy on StaMPS-PS Processing: A Case Study in Shenzhen, China

Directory of Open Access Journals (Sweden)

Yanan Du

2017-11-01

Full Text Available External Digital Elevation Models (DEMs with different resolutions and accuracies cause different topographic residuals in differential interferograms of Multi-temporal InSAR (MTInSAR, especially for the phase-based StaMPS-PS. The PS selection and deformation parameter estimation of StaMPS-PS are closely related to the spatially uncorrected error, which is directly affected by external DEMs. However, it is still far from clear how the high resolution and accurate external DEM affects the results of the StaMPS-PS (e.g., PS selection and deformation parameter calculation on different platforms (X band TerraSAR, C band ENVISAT ASAR and L band ALOS/PALSAR1. In this study, abundant synthetic tests are performed to assess the influences of external DEMs on parameter estimations, such as the mean deformation rate and the deformation time-series. Real SAR images, covering Shenzhen city in China, are also selected to analyze the PS selection and distribution as well as to validate the results of synthetic tests. The results show that the PS points selected by the 5 m TanDEM-X DEM are 10.32%, 4.25% and 0.34% more than those selected by the 30 m SRTM DEM at X, C and L bands SAR platforms, respectively, when a multi-look geocoding operation is adopted for X band in the SRTM DEM case. We also find that the influences of external DEMs on the mean deformation rate are not significant and are inversely proportional to the wavelength of the satellite platforms. The standard deviations of the mean deformation rate difference for the X, C and L bands are 0.54, 0.30 and 0.10 mm/year, respectively. Similarly, the influences of external DEMs on the deformation time-series estimation for the three platforms are also slight, except for local artifacts whose root-mean-square error (RMSE ≥ 6 mm. Based on these analyses, some implications and suggestions for external DEMs on StaMPS-PS processing are discussed and provided.

Sub-10ps monolithic and low-power photodetector readout

International Nuclear Information System (INIS)

Varner, Gary S.; Ruckman, Larry L.

2009-01-01

Recent advances in photon detectors have resulted in high-density imaging arrays that offer many performance and cost advantages. In particular, the excellent transit time spread of certain devices show promise to provide tangible benefits in applications such as Positron Emission Tomography (PET). Meanwhile, high-density, high-performance readout techniques have not kept on pace for exploiting these developments. Photodetector readout for next generation high event rate particle identification and time-resolved PET requires a highly-integrated, low-power, and cost-effective readout technique. We propose fast waveform sampling as a method that meets these criteria and demonstrate that sub-10ps resolution can be obtained for an existing device

Sub-10ps monolithic and low-power photodetector readout

Energy Technology Data Exchange (ETDEWEB)

Varner, Gary S.; Ruckman, Larry L.

2009-02-20

Recent advances in photon detectors have resulted in high-density imaging arrays that offer many performance and cost advantages. In particular, the excellent transit time spread of certain devices show promise to provide tangible benefits in applications such as Positron Emission Tomography (PET). Meanwhile, high-density, high-performance readout techniques have not kept on pace for exploiting these developments. Photodetector readout for next generation high event rate particle identification and time-resolved PET requires a highly-integrated, low-power, and cost-effective readout technique. We propose fast waveform sampling as a method that meets these criteria and demonstrate that sub-10ps resolution can be obtained for an existing device.

Timing resolution improvement using DOI information in a four-layer scintillation detector for TOF-PET

Energy Technology Data Exchange (ETDEWEB)

Shibuya, Kengo [jPET Project Team, Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-0024 (Japan)], E-mail: shibuken@gakushikai.jp; Nishikido, Fumihiko [jPET Project Team, Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-0024 (Japan); Tsuda, Tomoaki [Technology Research Laboratory, Shimadzu Corporation, Hikaridai 3-9-4, Seika-cho, Kyoto 619-0237 (Japan); Kobayashi, Tetsuya [Department of Medical System Engineering, Graduate School of Engineering, Chiba University, Yayoi 1-33, Inage-ku, Chiba 263-8522 (Japan); Lam, Chihfung; Yamaya, Taiga; Yoshida, Eiji; Inadama, Naoko; Murayama, Hideo [jPET Project Team, Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-0024 (Japan)

2008-08-11

Depth-of-interaction (DOI) detectors are considered to be advantageous for time-of-flight positron emission tomography (TOF-PET) because they can correct timing errors arising in the scintillation crystals due to a propagation speed difference between annihilation radiation and scintillation photons. We experimentally measured this timing error, using our four-layer DOI encoding method. The upper layers exhibited the larger timing delays due to the longer path lengths after conversion from annihilation radiation into scintillation photons that traveled by zigzag paths at a speed decreased by a factor of the refractive index (n). The maximum timing delay between the uppermost and the lowermost layers was evaluated as 164 ps when n=1.47. A TOF error correction was demonstrated to improve the timing resolution of the four-layer DOI detector by 10.3%, which would increase the effective sensitivity of the scanner by about 12% comparison with a non-DOI TOF-PET scanner. This is the first step towards combining these two important fields in PET instrumentation, namely DOI and TOF, for the purpose of achieving a higher sensitivity as well as a more uniform spatial resolution.

A fast, noniterative approach for accelerated high-temporal resolution cine-CMR using dynamically interleaved streak removal in the power-spectral encoded domain with low-pass filtering (DISPEL) and modulo-prime spokes (MoPS).

Science.gov (United States)

Kawaji, Keigo; Patel, Mita B; Cantrell, Charles G; Tanaka, Akiko; Marino, Marco; Tamura, Satoshi; Wang, Hui; Wang, Yi; Carroll, Timothy J; Ota, Takeyoshi; Patel, Amit R

2017-07-01

To introduce a pair of accelerated non-Cartesian acquisition principles that when combined, exploit the periodicity of k-space acquisition, and thereby enable acquisition of high-temporal cine Cardiac Magnetic Resonance (CMR). The mathematical formulation of a noniterative, undersampled non-Cartesian cine acquisition and reconstruction is presented. First, a low-pass filtering step that exploits streaking artifact redundancy is provided (i.e., Dynamically Interleaved Streak removal in the Power-spectrum Encoded domain with Low-pass filtering [DISPEL]). Next, an effective radial acquisition for the DISPEL approach that exploits the property of prime numbers is described (i.e., Modulo-Prime Spoke [MoPS]). Both DISPEL and MoPS are examined using numerical simulation of a digital heart phantom to show that high-temporal cine-CMR is feasible without removing physiologic motion vs aperiodic interleaving using Golden Angles. The combined high-temporal cine approach is next examined in 11 healthy subjects for a time-volume curve assessment of left ventricular systolic and diastolic performance vs conventional Cartesian cine-CMR reference. The DISPEL method was first shown using simulation under different streak cycles to allow separation of undersampled radial streaking artifacts from physiologic motion with a sufficiently frequent streak-cycle interval. Radial interleaving with MoPS is next shown to allow interleaves with pseudo-Golden-Angle variants, and be more compatible with DISPEL against irrational and nonperiodic rotation angles, including the Golden-Angle-derived rotations. In the in vivo data, the proposed method showed no statistical difference in the systolic performance, while diastolic parameters sensitive to the cine's temporal resolution were statistically significant (P cine). We demonstrate a high-temporal resolution cine-CMR using DISPEL and MoPS, whose streaking artifact was separated from physiologic motion. © 2017 American Association of Physicists

Framing-camera tube developed for sub-100-ps range

International Nuclear Information System (INIS)

Anon.

1978-01-01

A new framing-camera tube, developed by Electronics Engineering, is capable of recording two-dimensional image frames with high spatial resolution in the sub-100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits; the resulting electron-line images from the slits are restored into a framed image by a restorer deflector operating synchronously with the dissector deflector. We have demonstrated its performance in a prototype tube by recording 125-ps-duration framed images of 2.5-mm patterns. The limitation in the framing speed is in the external electronic drivers for the deflectors and not in the tube design characteristics. Shorter frame durations (below 100 ps) can be obtained by use of faster deflection drivers

Theoretical considerations regarding the existence of PsO and PsS+

International Nuclear Information System (INIS)

Farazdel, A.; Cade, P.E.

1977-01-01

It has been proposed from experimental studies and in analogy with hydrogen compounds that PsO may be an entity of some importance, or an intermediate, in the reaction of positronium, Ps, with aqueous oxyacid species such as H 2 PO 4 - , HSO 4 - , ClO 4 - , and NO 3 - . This communication explores the stability of PsO and PsS, or [O - :e + ] and [S - :e + ], respectively, relative to dissociation into Ps and O( 3 P) or S( 3 P) on the basis of restricted Hartree-Fock calculations for the PsO and PsS systems and certain correlation correction arguments. A reasonable lower estimate of the dissociation energy to Y+Ps of >-0.47 eV for PsO and >0.70 eV for PsS is obtained. It is suggested that a modest correlation correction to the positron affinity (PA) of O - would very probably lead to a bound state system for PsO. (Auth.)

High resolution spectrometry for relativistic heavy ions

Energy Technology Data Exchange (ETDEWEB)

Gabor, G; Schimmerling, W; Greiner, D; Bieser, F; Lindstrom, P [California Univ., Berkeley (USA). Lawrence Berkeley Lab.

1975-12-01

Several techniques are discussed for velocity and energy spectrometry of relativistic heavy ions with good resolution. A foil telescope with chevron channel plate detectors is described. A test of this telescope was performed using 2.1 GeV/A C/sup 6 +/ ions, and a time-of-flight resolution of 160 ps was measured. Qualitative information on the effect of foil thickness was also obtained.

Temporal resolution technology of a soft X-ray picosecond framing camera based on Chevron micro-channel plates gated in cascade

Energy Technology Data Exchange (ETDEWEB)

Yang Wenzheng [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China)], E-mail: ywz@opt.ac.cn; Bai Yonglin; Liu Baiyu [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Bai Xiaohong; Zhao Junping; Qin Junjun [Key Laboratory of Ultra-fast Photoelectric Diagnostics Technology, Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China)

2009-09-11

We describe a soft X-ray picosecond framing camera (XFC) based on Chevron micro-channel plates (MCPs) gated in cascade for ultra-fast process diagnostics. The micro-strip lines are deposited on both the input and the output surfaces of the Chevron MCPs and can be gated by a negative (positive) electric pulse on the first (second) MCP. The gating is controlled by the time delay T{sub d} between two gating pulses. By increasing T{sub d}, the temporal resolution and the gain of the camera are greatly improved compared with a single-gated MCP-XFC. The optimal T{sub d}, which results in the best temporal resolution, is within the electron transit time and transit time spread of the MCP. Using 250 ps, {+-}2.5 kV gating pulses, the temporal resolution of the double-gated Chevron MCPs camera is improved from 60 ps for the single-gated MCP-XFC to 37 ps for T{sub d}=350 ps. The principle is presented in detail and accompanied with a theoretic simulation and experimental results.

A four channel time-to-digital converter ASIC with in-built calibration and SPI interface

International Nuclear Information System (INIS)

Hari Prasad, K.; Sukhwani, Menka; Saxena, Pooja; Chandratre, V.B.; Pithawa, C.K.

2014-01-01

A design of high resolution, wide dynamic range Time-to-Digital Converter (TDC) ASIC, implemented in 0.35 µm commercial CMOS technology is presented. The ASIC features four channel TDC with an in-built calibration and Serial Peripheral Interconnect (SPI) slave interface. The TDC is based on the vernier ring oscillator method in order to achieve both high resolution and wide dynamic range. This TDC ASIC is tested and found to have resolution of 127 ps (LSB), dynamic range of 1.8 µs and precision (σ) of 74 ps. The measured values of differential non-linearity (DNL) and integral non-linearity (INL) are 350 ps and 300 ps respectively

An FPGA-Integrated Time-to-Digital Converter Based on a Ring Oscillator for Programmable Delay Line Resolution Measurement

Directory of Open Access Journals (Sweden)

Chao Chen

2014-01-01

Full Text Available We describe the architecture of a time-to-digital converter (TDC, specially intended to measure the delay resolution of a programmable delay line (PDL. The configuration, which consists of a ring oscillator, a frequency divider (FD, and a period measurement circuit (PMC, is implemented in a field programmable gate array (FPGA device. The ring oscillator realized in loop containing a PDL and a look-up table (LUT generates periodic oscillatory pulses. The FD amplifies the oscillatory period from nanosecond range to microsecond range. The time-to-digital conversion is based on counting the number of clock cycles between two consecutive pulses of the FD by the PMC. Experiments have been conducted to verify the performance of the TDC. The achieved relative errors for four PDLs are within 0.50%–1.21% and the TDC has an equivalent resolution of about 0.4 ps.

LS1 Report: PS beams are back!

CERN Multimedia

Katarina Anthony & Anaïs Schaeffer

2014-01-01

For the first time in over 15 months, there are beams back in the PS. Making their first tour of the accelerator today, 20 June, their injection marks the end of weeks of cold checkouts and hardware commissioning in the PS.   The CERN Control Centre (CCC) is back in business: people gather to restart the LHC injectors, today the PS. Since hardware commissioning was wrapped up on 23 May, the Operations Group (BE-OP) has been conducting cold checkouts on the PS. This involves switching on all of the machine's systems, verifying that they respond to commands by OP and ensuring they are calibrated to beam timings. "These verifications were done, in part, during the hardware commissioning dry runs," says Rende Steerenberg, PS section leader. "But the cold checkouts are on a much larger scale, as we act as if there is beam in the whole machine. We placed a full load on the controls system, cooling, networks, etc. in order to setup the accelerator in the most realis...

Investigation of a Multi-Anode Microchannel Plate PMT for Time-of-Flight PET

Science.gov (United States)

Choong, Woon-Seng

2010-10-01

We report on an investigation of a mulit-anode microchannel plate PMT for time-of-flight PET detector modules. The primary advantages of an MCP lie in its excellent timing properties (fast rise time and low transit time spread), compact size, and reasonably large active area, thus making it a good candidate for TOF applications. In addition, the anode can be segmented into an array of collection electrodes with fine pitch to attain good position sensitivity. In this paper, we investigate using the Photonis Planacon MCP-PMT with a pore size of 10 μm to construct a PET detector module, specifically for time-of-flight applications. We measure the single electron response by exciting the Planacon with pulsed laser diode. We also measure the performance of the Planacon as a PET detector by coupling a 4 mm×4 mm×10 mm LSO crystal to individual pixel to study its gain uniformity, energy resolution, and timing resolution. The rise time of the Planacon is 440 ps with pulse duration of about 1 ns. A transit time spread of 120 ps FWHM is achieved. The gain is fairly uniform across the central region of the Planacon, but drops off by as much as a factor of 2.5 around the edges. The energy resolution is fairly uniform across the Planacon with an average value of 18.6 ± 0.7% FWHM. While the average timing resolution of 252 ± 7 ps FWHM is achieved in the central region of the Planacon, it degrades to 280 ± 9 ps FWHM for edge pixels and 316 ± 15 ps FWHM for corner pixels. We compare the results with measurements performed with a fast timing conventional PMT (Hamamatsu R-9800). We find that the R9800, which has significantly higher PDE, has a better timing resolution than the Planacon. Furthermore, we perform detector simulations to calculate the improvement that can be achieved with a higher PDE Planacon. The calculation shows that the Planacon can achieve significantly better timing resolution if it can attain the same PDE as the R-9800, while only a 30% improvement is

The PS complex as proton pre-injector for the LHC - design and implementation report

International Nuclear Information System (INIS)

Benedikt, M.; Blas, A.; Borburgh, J.

2000-01-01

The LHC will be supplied with protons from the pre-injector chain comprising Linac2, PS Booster and PS. These accelerators have undergone a major upgrading programme during the last five years so as to meet the stringent requirements of the LHC. This implies that many high-intensity bunches of small emittance and tight spacing (25 ns) be available at the PS extraction energy (26 GeV/c). The upgrading project involved an increase of Linac2 current, new RF systems in the PS Booster and the PS, raising the PS Booster energy from 1 to 1.4 GeV, two-batch filling of the PS, and the installation of high-resolution beam profile measurement devices. With the project entering its final phase and most of the newly installed hardware now being operational, the emphasis switches to producing the nominal LHC beam and tackling the associated beam physics problems. This report describes all the hardware changes related to the upgrading project. (orig.)

Barrel time-of-flight detector for the PANDA experiment at FAIR

Science.gov (United States)

Gruber, L.; Brunner, S. E.; Marton, J.; Orth, H.; Suzuki, K.; PANDA Tof Group

2016-07-01

The barrel time-of-flight detector for the PANDA experiment at FAIR is foreseen as a Scintillator Tile (SciTil) Hodoscope based on several thousand small plastic scintillator tiles read-out with directly attached Silicon Photomultipliers (SiPMs). The main tasks of the system are an accurate determination of the time origin of particle tracks to avoid event mixing at high collision rates, relative time-of-flight measurements as well as particle identification in the low momentum regime. The main requirements are the use of a minimum material amount and a time resolution of σ < 100 ps. We have performed extensive optimization studies and prototype tests to prove the feasibility of the SciTil design and finalize the R&D phase. In a 2.7 GeV/c proton beam at Forschungszentrum Jülich a time resolution of about 80 ps has been achieved using SiPMs from KETEK and Hamamatsu with an active area of 3 × 3mm2. Employing the Digital Photon Counter from Philips a time resolution of about 30 ps has been reached.

Study of time resolution by digital methods with a DRS4 module

Science.gov (United States)

Du, Cheng-Ming, Du; Jin-Da, Chen; Xiu-Ling, Zhang; Yang, Hai-Bo; Cheng, Ke; Kong, Jie; Hu, Zheng-Guo; Sun, Zhi-Yu; Su, Hong; Xu, Hu-Shan

2016-04-01

A new Digital Pulse Processing (DPP) module has been developed, based on a domino ring sampler version 4 chip (DRS4), with good time resolution for LaBr3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes (PMTs). Two PMTs were coupled with LaBr3 scintillators and placed on opposite sides of a radioactive positron 22Na source for 511 keV γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps (FWHM), obtained by the digital constant fraction discrimination (dCFD) method, which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography (PET) with time of flight (TOF), as well as for scintillation timing measurement, such as in TOF-ΔE and TOF-E systems for particle identification, with picosecond accuracy timing measurement. Furthermore, this module is more simple and convenient than other systems. Supported by the Science Foundation of the Chinese Academy of Sciences (210340XBO), National Natural Science Foundation of China (11305233,11205222), General Program of National Natural Science Foundation of China (11475234), Specific Fund of National Key Scientific Instrument and Equipment Development Project (2011YQ12009604) and Joint Fund for Research Based on Large-Scale Scientific Facilities (U1532131).

Reduction of the jitter of single-flux-quantum time-to-digital converters for time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Sano, K.; Muramatsu, Y.; Yamanashi, Y.; Yoshikawa, N.; Zen, N.; Ohkubo, M.

2014-01-01

Highlights: • We proposed single-flux-quantum (SFQ) time-to-digital converters (TDCs) for TOF-MS. • SFQ TDC can measure time intervals between multiple signals with high-resolution. • SFQ TDC can directly convert the time intervals into binary data. • We designed two types of SFQ TDCs to reduce the jitter. • The jitter is reduced to less than 100 ps. - Abstract: We have been developing a high-resolution superconducting time-of-flight mass spectrometry (TOF-MS) system, which utilizes a superconducting strip ion detector (SSID) and a single-flux-quantum (SFQ) time-to-digital converter (TDC). The SFQ TDC can measure time intervals between multiple input signals and directly convert them into binary data. In our previous study, 24-bit SFQ TDC with a 3 × 24-bit First-In First-Out (FIFO) buffer was designed and implemented using the AIST Nb standard process 2 (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. In this study we reduce the jitter of the TDC by using two different approaches: one uses an on-chip clock generator with an on-chip low-pass filter for reducing the noise in the bias current, and the other uses a low-jitter external clock source at room temperature. We confirmed that the jitter is reduced to less than 100 ps in the latter approach

Reduction of the jitter of single-flux-quantum time-to-digital converters for time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Sano, K., E-mail: sano-kyosuke-cw@ynu.jp [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Muramatsu, Y.; Yamanashi, Y.; Yoshikawa, N. [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Zen, N.; Ohkubo, M. [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

2014-09-15

Highlights: • We proposed single-flux-quantum (SFQ) time-to-digital converters (TDCs) for TOF-MS. • SFQ TDC can measure time intervals between multiple signals with high-resolution. • SFQ TDC can directly convert the time intervals into binary data. • We designed two types of SFQ TDCs to reduce the jitter. • The jitter is reduced to less than 100 ps. - Abstract: We have been developing a high-resolution superconducting time-of-flight mass spectrometry (TOF-MS) system, which utilizes a superconducting strip ion detector (SSID) and a single-flux-quantum (SFQ) time-to-digital converter (TDC). The SFQ TDC can measure time intervals between multiple input signals and directly convert them into binary data. In our previous study, 24-bit SFQ TDC with a 3 × 24-bit First-In First-Out (FIFO) buffer was designed and implemented using the AIST Nb standard process 2 (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. In this study we reduce the jitter of the TDC by using two different approaches: one uses an on-chip clock generator with an on-chip low-pass filter for reducing the noise in the bias current, and the other uses a low-jitter external clock source at room temperature. We confirmed that the jitter is reduced to less than 100 ps in the latter approach.

Asymmetric PS-block-(PS-co-PB)-block-PS block copolymers: morphology formation and deformation behaviour

International Nuclear Information System (INIS)

Adhikari, Rameshwar; Huy, Trinh An; Buschnakowski, Matthias; Michler, Goerg H; Knoll, Konrad

2004-01-01

Morphology formation and deformation behaviour of asymmetric styrene/butadiene triblock copolymers (total polystyrene (PS) content ∼70%) consisting of PS outer blocks held apart by a styrene-co-butadiene random copolymer block (PS-co-PB) each were investigated. The techniques used were differential scanning calorimetry, transmission electron microscopy, uniaxial tensile testing and Fourier-transform infrared spectroscopy. A significant shift of the phase behaviour relative to that of a neat symmetric triblock copolymer was observed, which can be attributed to the asymmetric architecture and the presence of PS-co-PB as a soft block. The mechanical properties and the microdeformation phenomena were mainly controlled by the nature of their solid-state morphology. Independent of morphology type, the soft phase was found to deform to a significantly higher degree of orientation when compared with the hard phase

Synthesis of NiPS3 and CoPS and its hydrogen storage capacity

International Nuclear Information System (INIS)

Ismail, N.; Madian, M.; El-Meligi, A.A.

2014-01-01

Highlights: • Preparation of NiPS 3 and CoPS using solid state reaction. • Characterization of compounds using XRD, TEM, SEM and IR. • Measuring the compounds thermal stability. • Estimation of the hydrogen storage capacity. -- Abstract: Prepared CoPS and NiPS 3 are studied as new materials for hydrogen energy storage. Single phase of CoPS and NiPS 3 were grown separately in evacuated silicatube via solid state reaction at 650 °C with controlled heating rate 1 °C/min. X-ray diffraction patterns confirm the formation of the desired compounds. Both CoPS and NiPS 3 exhibited high thermal stability up to 700 °C and 630 °C, respectively. The morphology of the prepared samples was investigated using scanning electron microscopy and folded sheets appeared in the transmission electron microscopy. The samples were exposed to 20 bar applied hydrogen pressure at 80 K. Both compounds appear to have feasible hydrogen storage capacity. CoPS was capable to adsorb 1.7 wt% while NiPS 3 storage capacity reached 1.2 wt%

Subnanosecond timing with ion-implanted detectors

International Nuclear Information System (INIS)

Rijken, H.A.; Klein, S.S.; Jacobs, W.; Teeuwen, L.J.H.G.W.; Voigt, M.J.A. de; Burger, P.

1992-01-01

The energy resolution of ion-implanted charged particle detectors may be improved by decreasing the thickness of the implanted detector window to minimize energy straggling. Because of the resistance of this layer, however, the timing depends on the position of entry. Two solutions to this conflict between energy resolution and time resolution are studied: evaporating a very thin aluminum layer on the detector window and fabricating a rectangular detector. Both solutions are shown to be successful with a total time resolution in the low subnanosecond region (<200 ps). (orig.)

The PS Booster hits 40

CERN Multimedia

Joannah Caborn Wengler

2012-01-01

Many accelerators’ "round" birthdays are being celebrated at CERN these days – the PS turned 50 in 2009, the SPS was 35 in 2011, and this year it's the turn of the PS Booster to mark its 40th anniversary. Originally designed to accelerate 1013 protons to 800 MeV, it has far exceeded its initial design performance over the years.   The PS Booster in the 1970s. Imagine the scene: a group of accelerator physicists staring expectantly at a monitor, when suddenly a shout of joy goes up as a signal flickers across the screen. Does that sound familiar? Well, turn the clock back 40 years (longer hair, wider trouser legs) and you have the situation at the PS Booster on 26 May 1972. On that day, beam was injected into the Booster for the first time. “It was a real buzz,” says Heribert Koziol, then Chairman of the Running-in Committee. “We were very happy – and also a little relieved – when the beam finally...

A comparative study of the time performance between NINO and FlexToT ASICs

International Nuclear Information System (INIS)

Sarasola, I.; Rato, P.; Marín, J.; Nemallapudi, M.V.; Gundacker, S.; Auffray, E.; Sánchez, D.; Gascón, D.

2017-01-01

Universitat de Barcelona (UB) and CIEMAT have designed the FlexToT ASIC for the front-end readout of SiPM-based scintillator detectors. This ASIC is aimed at time of flight (ToF) positron emission tomography (PET) applications. In this work we have evaluated the time performance of the FlexToT v2 ASIC compared to the NINO ASIC, a fast ASIC developped at CERN. NINO electronics give 64 ps sigma for single-photon time resolution (SPTR) and 93 ps FWHM for coincidence time resolution (CTR) with 2 × 2 × 5 mm 3 LSO:Ce,Ca crystals and S13360-3050CS SiPMs. Using the same SiPMs and crystals, the FlexToT v2 ASIC yields 91 ps sigma for SPTR and 123 ps FWHM for CTR. Despite worse time performace than NINO, FlexToT v2 features lower power consumption (11 vs. 27 mW/ch) and linear ToT energy measurement.

The PrPS4 type structure and a filled variant: the compounds TbPS4 and LiEuPS4

International Nuclear Information System (INIS)

Joergens, S.; Alili, L.; Mewis, A.

2005-01-01

Colourless single crystals of TbPS 4 (a = 10.696(2), c = 19.053(4) Aa) were obtained by reaction of the elements (750 C; 30 h). The compound crystallizes with the PrPS 4 type structure (I4 1 /acd; Z = 16). The structure consists of isolated PS 4 tetrahedra each surrounded by four Tb 3+ cations. Both crystallographically different Tb 3+ cations are coordinated by eight sulfur atoms which are part of four PS 4 tetrahedra. Orange single crystals of LiEuPS 4 (a = 11.498(2), c = 19.882(4) Aa) were prepared by reaction of Eu and P with Li 2 S 4 (700 C; 20 h). The crystal structure corresponds to the PrPS 4 type, in which tubes running along [001] are occupied by Li atoms, which are surrounded by four S atoms in strongly distorted tetrahedra. LiS 4 and PS 4 tetrahedra are connected via common edges into alternating chains. (orig.)

High precision timing in a FLASH

Energy Technology Data Exchange (ETDEWEB)

Hoek, Matthias; Cardinali, Matteo; Dickescheid, Michael; Schlimme, Soeren; Sfienti, Concettina; Spruck, Bjoern; Thiel, Michaela [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)

2016-07-01

A segmented highly precise start counter (FLASH) was designed and constructed at the Institute for Nuclear Physics in Mainz. Besides determining a precise reference time, a Time-of-Flight measurement can be performed with two identical FLASH units. Thus, particle identification can be provided for mixed hadron beam environments. The detector design is based on the detection of Cherenkov light produced in fused silica radiator bars with fast multi-anode MCP-PMTs. The segmentation of the radiator improves the timing resolution while allowing a coarse position resolution along one direction. Both, the arrival time and the Time-over-Threshold are determined by the readout electronics, which enables walk correction of the arrival time. The performance of two FLASH units was investigated in test experiments at the Mainz Microton (MAMI) using an electron beam with an energy of 855 MeV and at CERN's PS T9 beam line with a mixed hadron beam with momenta between 3-8 GeV/c. Effective Time-walk correction methods based on Time-over-Threshold were developed for the data analysis. The achieved Time-Of-Flight resolution after applying all corrections was found to be 70 ps. Furthermore, the PID and position resolution capabilities are discussed in this contribution.

Exact PsTd invariant and PsTd symmetric breaking solutions, symmetry reductions and Bäcklund transformations for an AB-KdV system

Science.gov (United States)

Jia, Man; Lou, Sen Yue

2018-05-01

In natural and social science, many events happened at different space-times may be closely correlated. Two events, A (Alice) and B (Bob) are defined as correlated if one event is determined by another, say, B = f ˆ A for suitable f ˆ operators. A nonlocal AB-KdV system with shifted-parity (Ps, parity with a shift), delayed time reversal (Td, time reversal with a delay) symmetry where B =Ps ˆ Td ˆ A is constructed directly from the normal KdV equation to describe two-area physical event. The exact solutions of the AB-KdV system, including PsTd invariant and PsTd symmetric breaking solutions are shown by different methods. The PsTd invariant solution show that the event happened at A will happen also at B. These solutions, such as single soliton solutions, infinitely many singular soliton solutions, soliton-cnoidal wave interaction solutions, and symmetry reduction solutions etc., show the AB-KdV system possesses rich structures. Also, a special Bäcklund transformation related to residual symmetry is presented via the localization of the residual symmetry to find interaction solutions between the solitons and other types of the AB-KdV system.

Recombination dynamics in coalesced a-plane GaN ELO structures investigated by high spatially and ps-time-resolved cathodoluminescence microscopy

Energy Technology Data Exchange (ETDEWEB)

Bastek, B.; Bertram, F.; Christen, J. [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg (Germany); Wernicke, T.; Weyers, M. [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Kneissl, M. [Institute of Solid State Physics, Technical University, Berlin (Germany)

2008-07-01

The characteristic epitaxial lateral overgrowth (ELO) domains of fully coalesced a-plane GaN layers were directly imaged by highly spatially and spectrally resolved cathodoluminescence microscopy (CL) at 5 K. The patterned layers were grown by MOVPE on r-plane sapphire substrate and stripe masks oriented in the [01 anti 10] direction. In the area of coherent growth (I) the broad basal plane stacking fault (BSF) emission centered at 3.41 eV dominates the spectra. Also in the region (II) of coalescence the BSF luminescence dominates, however, the intensity increases by one order of magnitude compared to area (I). In complete contrast, in the stripes associated with the laterally grown domains (III) in [0001] direction, exclusively an intense and sharp (D{sup 0},X) emission at 3.475 eV is observed. ps-time-resolved CL of the free excitons (FX) recorded from this domains (III) decays bi-exponentially. The initial lifetime of 180 ps is primarily given by the capture of FX by impurities to form bound excitons (BE). With rising temperature this capture time constant decreases as T{sup -1/4} and reaches a minimum of 104 ps at T=60 K. Above 60 K, i.e. when FX starts to dominate the BEs, the lifetime increases rapidly to a value of 240 ps for 300 K.

STiC — a mixed mode silicon photomultiplier readout ASIC for time-of-flight applications

International Nuclear Information System (INIS)

Harion, T; Briggl, K; Chen, H; Gil, A; Kiworra, V; Schultz-Coulon, H-C; Shen, W; Stankova, V; Fischer, P; Ritzert, M

2014-01-01

STiC is an application specific integrated circuit (ASIC) for the readout of silicon photomultipliers. The chip has been designed to provide a very high timing resolution for time-of-flight applications in medical imaging and particle physics. It is dedicated in particular to the EndoToFPET-US project, which is developing an endoscopic PET detector combined with ultrasound imaging for early pancreas and prostate cancer detection. This PET system aims to provide a spatial resolution of 1 mm and a time-of-flight resolution of 200 ps FWHM. The analog frontend of STiC can use either a differential or single ended connection to the SiPM. The time and energy information of the detector signal is encoded into two time stamps. A special linearized time-over-threshold method is used to obtain a linear relation between the signal charge and the measured signal width, improving the energy resolution. The trigger signals are digitized by an integrated TDC module with a resolution of less than 20 ps. The TDC data is stored in an internal memory and transfered over a 160 MBit/s serial link using 8/10 bit encoding. First coincidence measurements using a 3.1 × 3.1 × 15 mm 3 LYSO crystal and a S10362-33-50 Hamamtsu MPPC show a coincidence time resolution of less than 285 ps. We present details on the chip design as well as first characterization measurements

arXiv Time resolution of silicon pixel sensors

CERN Document Server

Riegler, W.

2017-11-21

We derive expressions for the time resolution of silicon detectors, using the Landau theory and a PAI model for describing the charge deposit of high energy particles. First we use the centroid time of the induced signal and derive analytic expressions for the three components contributing to the time resolution, namely charge deposit fluctuations, noise and fluctuations of the signal shape due to weighting field variations. Then we derive expressions for the time resolution using leading edge discrimination of the signal for various electronics shaping times. Time resolution of silicon detectors with internal gain is discussed as well.

Back to work for the PS

CERN Multimedia

2006-01-01

On 22 June, the PS's rotating machine started turning again for the first time since its enforced shutdown one month ago (see Bulletin No. 23-24/2006) - and the PS was back in operation the very next day! A team from Siemens worked their socks off, 6 days a week for one month (including public holidays), to repair the electrical power supply in collaboration with the AB/PO Group's Main Power Converters (MPC) Section. The generator's faulty rotor was dismantled and replaced by the renovated spare rotor. The multitude of electrical and mechanical connections together with the sheer weight of the rotor (80 tonnes) made this an extremely complex job. The AB/PO Group used the shutdown to test a back-up solution for the PS power supply. The accelerator was directly wired up to the 18 kV electrical network via a 13 MVA transformer, installed at the end of the 1970s but never used. This solution succeeded in bringing the PS back into operation but at limited energy and frequency. Just 14 GeV could be achieved, whic...

High-performance electronics for time-of-flight PET systems

International Nuclear Information System (INIS)

Choong, W-S; Peng, Q; Vu, C Q; Turko, B T; Moses, W W

2013-01-01

We have designed and built a high-performance readout electronics system for time-of-flight positron emission tomography (TOF PET) cameras. The electronics architecture is based on the electronics for a commercial whole-body PET camera (Siemens/CPS Cardinal electronics), modified to improve the timing performance. The fundamental contributions in the electronics that can limit the timing resolution include the constant fraction discriminator (CFD), which converts the analog electrical signal from the photo-detector to a digital signal whose leading edge is time-correlated with the input signal, and the time-to-digital converter (TDC), which provides a time stamp for the CFD output. Coincident events are identified by digitally comparing the values of the time stamps. In the Cardinal electronics, the front-end processing electronics are performed by an Analog subsection board, which has two application-specific integrated circuits (ASICs), each servicing a PET block detector module. The ASIC has a built-in CFD and TDC. We found that a significant degradation in the timing resolution comes from the ASIC's CFD and TDC. Therefore, we have designed and built an improved Analog subsection board that replaces the ASIC's CFD and TDC with a high-performance CFD (made with discrete components) and TDC (using the CERN high-performance TDC ASIC). The improved Analog subsection board is used in a custom single-ring LSO-based TOF PET camera. The electronics system achieves a timing resolution of 60 ps FWHM. Prototype TOF detector modules are read out with the electronics system and give coincidence timing resolutions of 259 ps FWHM and 156 ps FWHM for detector modules coupled to LSO and LaBr 3 crystals respectively.

Time expanding multihit TDC for the BELLE TOF detector at the KEK B-factory

International Nuclear Information System (INIS)

Varner, G.; Kichimi, H.; Yamaguchi, H.

1997-01-01

Utilizing a time expansion technique, a multihit TDC has been developed for readout of the BELLE TOF detector at the KEK B-Factory. Time digitization consists of three steps: tagging an input signal with respect to a beam collision synchronized reference clock, expansion of this time interval, and readout by a conventional multihit TDC. Using a time expansion factor of 20 and a multihit TDC with a 500 ps LSB, this system provides a precision TOF measurement of 25 ps LSB, ∼20 ps resolution, and with a dead time of less than 1 μs

Time-resolved study of formate on Ni( 1 1 1 ) by picosecond SFG spectroscopy

Science.gov (United States)

Kusafuka, K.; Noguchi, H.; Onda, K.; Kubota, J.; Domen, K.; Hirose, C.; Wada, A.

2002-04-01

Time-resolved vibrational measurements were carried out on formate (HCOO) adsorbed on Ni(1 1 1) surface by combining the sum-frequency generation method and picosecond laser system (time resolution of 6 ps). Rapid intensity decrease (within the time resolution) followed by intensity recovery (time constant of several tens of ps) of CH stretching signal was observed when picosecond 800 nm pulse was irradiated on the sample surface. From the results of temperature and pump fluence dependences of temporal behaviour of signal intensity, we concluded that the observed intensity change was induced by non-thermal process. Mechanism of the temporal intensity change was discussed.

A new timing model for calculating the intrinsic timing resolution of a scintillator detector

International Nuclear Information System (INIS)

Shao Yiping

2007-01-01

The coincidence timing resolution is a critical parameter which to a large extent determines the system performance of positron emission tomography (PET). This is particularly true for time-of-flight (TOF) PET that requires an excellent coincidence timing resolution (<<1 ns) in order to significantly improve the image quality. The intrinsic timing resolution is conventionally calculated with a single-exponential timing model that includes two parameters of a scintillator detector: scintillation decay time and total photoelectron yield from the photon-electron conversion. However, this calculation has led to significant errors when the coincidence timing resolution reaches 1 ns or less. In this paper, a bi-exponential timing model is derived and evaluated. The new timing model includes an additional parameter of a scintillator detector: scintillation rise time. The effect of rise time on the timing resolution has been investigated analytically, and the results reveal that the rise time can significantly change the timing resolution of fast scintillators that have short decay time constants. Compared with measured data, the calculations have shown that the new timing model significantly improves the accuracy in the calculation of timing resolutions

Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays

Science.gov (United States)

Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

2017-10-01

Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays.

Science.gov (United States)

Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

2017-10-20

Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

Optical timing receiver for the NASA Spaceborne Ranging System. Part II: high precision event-timing digitizer

Energy Technology Data Exchange (ETDEWEB)

Leskovar, Branko; Turko, Bojan

1978-08-01

Position-resolution capabilities of the NASA Spaceborne Laser Ranging System are essentially determined by the timeresolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device; (e.g., photomultiplier or an avalanche photodiode detector), a timing discriminator, a high-precision event-timing digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the resolution of the event-timing digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to the time-resolution capabilities, and to develop a very low time walk timing discriminator and a high-resolution event-timing digitizer to be used in the high-resolution spaceborne laser ranging system receiver. This part of the report describes the development of a high precision event-timing digitizer. The event-timing digitizer is basically a combination of a very accurate high resolution real time digital clock and an interval timer. The timing digitizer is a high resolution multiple stop clock, counting the time up to 131 days in 19.5 ps increments.

High resolution radar satellite imagery analysis for safeguards applications

Energy Technology Data Exchange (ETDEWEB)

Minet, Christian; Eineder, Michael [German Aerospace Center, Remote Sensing Technology Institute, Department of SAR Signal Processing, Wessling, (Germany); Rezniczek, Arnold [UBA GmbH, Herzogenrath, (Germany); Niemeyer, Irmgard [Forschungszentrum Juelich, Institue of Energy and Climate Research, IEK-6: Nuclear Waste Management and Reactor Safety, Juelich, (Germany)

2011-12-15

For monitoring nuclear sites, the use of Synthetic Aperture Radar (SAR) imagery shows essential promises. Unlike optical remote sensing instruments, radar sensors operate under almost all weather conditions and independently of the sunlight, i.e. time of the day. Such technical specifications are required both for continuous and for ad-hoc, timed surveillance tasks. With Cosmo-Skymed, TerraSARX and Radarsat-2, high-resolution SAR imagery with a spatial resolution up to 1m has recently become available. Our work therefore aims to investigate the potential of high-resolution TerraSAR data for nuclear monitoring. This paper focuses on exploiting amplitude of a single acquisition, assessing amplitude changes and phase differences between two acquisitions, and PS-InSAR processing of an image stack.

Time lens for high-resolution neutron time-of-flight spectrometers

International Nuclear Information System (INIS)

Baumann, K.; Gaehler, R.; Grigoriev, P.; Kats, E.I.

2005-01-01

We examine in analytic and numeric ways the imaging effects of temporal neutron lenses created by traveling magnetic fields. For fields of parabolic shape we derive the imaging equations, investigate the time magnification, the evolution of the phase-space element, the gain factor, and the effect of finite beam size. The main aberration effects are calculated numerically. The system is technologically feasible and should convert neutron time-of-flight instruments from pinhole to imaging configuration in time, thus enhancing intensity and/or time resolution. Further fields of application for high-resolution spectrometry may be opened

Determination of grafting conversion degree in PS/PS-graft-POSS/POSS hybrid nanocomposites obtained through reactive processing

International Nuclear Information System (INIS)

Bianchi, Otavio; Repenning, Gustavo B.; Mauler, Raquel S.; Oliveira, Ricardo V.B.; Canto, Leonardo B.

2011-01-01

Hybrid nanocomposites of polystyrene (PS) and polyhedral oligomeric silsesquioxanes (POSS) - PS/PS-graft-POSS/POSS - with different grafting degrees were prepared by reactive melt processing using dicumyl peroxide (DCP) as initiator in the presence or absence of styrene monomer as radical transfer agent. Gel permeation chromatography (GPC) using triple-detector and proton nuclear magnetic resonance (NMR 1 H) analyses were used together to determine the conversion degree of PS-graft-POSS as a function of the reactive processing conditions adopted. GPC was employed to evaluate the effects of grafting (PS-graft-POSS) and PS chains degradation (β scission) that occur simultaneously during processing on the variation of average molecular masses and distributions for each PS/POSS sample. PS/POSS systems processed with styrene showed higher weight average molecular weights (M w ) and lower polydispersity indexes (M w /M n ), as a result of higher grafting (PS-graft-POSS) conversion (28-40%) and lower PS chain degradation level, as compared to PS/POSS systems processed without styrene in which the degree of grafting conversion was around 25-28%. (author)

Delay-line cables for the fast bumpers in the PS.

CERN Multimedia

CERN PhotoLab

1976-01-01

For 'continuous transfer' to the SPS, the beam accelerated in the PS is shaved off over several turns, so as to form a continuous sequence of bunches several times the length of the PS circumference. Fast bumpers, powered in a 'staircase' way, displace the PS beam stepwise towards the ejection septum. Each step lasts 2.1 microsec and the cable drums in this picture contain some of the bumper delay-lines of altogether 10 km.

A design of high resolution one-clock-cycle TDC based on FPGA

International Nuclear Information System (INIS)

Qi Ji; Deng Zhi; Liu Yinong

2011-01-01

It describes an FPGA-based high resolution TDC. Using delay chain and Wave Union methods, this TDC has a resolution of 9 ps, which is comparable to ASIC TDC. The design uses XORs and MUXs to implement a quick 1 -cycle encoder, which reduces the dead time. Self-calibration method makes the design easy to be migrated into other FPGAs. This TDC can be used in TOF experiment, medical imaging system, etc (authors)

Time-resolved spectroscopy of laser-induced breakdown in water

Science.gov (United States)

Thomas, Robert J.; Hammer, Daniel X.; Noojin, Gary D.; Stolarski, David J.; Rockwell, Benjamin A.; Roach, William P.

1996-05-01

Laser pulses of 60-ps and 80-ps at a wavelength of 532-nm and 1064-nm respectively were used to produce laser induced breakdown in triple-distilled water. The resulting luminescent flash from the plasma was captured with an imaging spectrograph coupled to a streak camera with a 5-ps time resolution. The wavelength range was 350 to 900-nm. We present the resulting experimental data which gives plasma duration and time-resolved spectral information. Plasma temperature is also computed from the data. All parameters are presented at a pulse energy of 1-mJ and are compared with time-integrated spectra at the same pulse duration and at 5 to 7-ns pulse duration in a similar energy range.

ps-ro Fuzzy Open(Closed Functions and ps-ro Fuzzy Semi-Homeomorphism

Directory of Open Access Journals (Sweden)

Pankaj Chettri

2015-11-01

Full Text Available The aim of this paper is to introduce and characterize some new class of functions in a fuzzy topological space termed as ps-ro fuzzy open(closed functions, ps-ro fuzzy pre semiopen functions and ps-ro fuzzy semi-homeomorphism. The interrelation among these concepts and also their relations with the parallel existing concepts are established. It is also shown with the help of examples that these newly introduced concepts are independent of the well known existing allied concepts.

Last PS magnet refurbished

CERN Multimedia

2009-01-01

PS Magnet Refurbishment Programme Completed. The 51st and final refurbished magnet was transported to the PS on Tuesday 3 February. The repair and consolidation work on the PS started back in 2003 when two magnets and a busbar connection were found to be faulty during routine high-voltage tests. The cause of the fault was a combination of age and radiation on electrical insulation. After further investigation the decision was taken to overhaul half of the PS’s 100 magnets to reduce the risk of a similar fault. As from 20 February the PS ring will start a five-week test programme to be ready for operation at the end of March.

High speed, High resolution terahertz spectrometers

International Nuclear Information System (INIS)

Kim, Youngchan; Yee, Dae Su; Yi, Miwoo; Ahn, Jaewook

2008-01-01

A variety of sources and methods have been developed for terahertz spectroscopy during almost two decades. Terahertz time domain spectroscopy (THz TDS)has attracted particular attention as a basic measurement method in the fields of THz science and technology. Recently, asynchronous optical sampling (AOS)THz TDS has been demonstrated, featuring rapid data acquisition and a high spectral resolution. Also, terahertz frequency comb spectroscopy (TFCS)possesses attractive features for high precision terahertz spectroscopy. In this presentation, we report on these two types of terahertz spectrometer. Our high speed, high resolution terahertz spectrometer is demonstrated using two mode locked femtosecond lasers with slightly different repetition frequencies without a mechanical delay stage. The repetition frequencies of the two femtosecond lasers are stabilized by use of two phase locked loops sharing the same reference oscillator. The time resolution of our terahertz spectrometer is measured using the cross correlation method to be 270 fs. AOS THz TDS is presented in Fig. 1, which shows a time domain waveform rapidly acquired on a 10ns time window. The inset shows a zoom into the signal with 100ps time window. The spectrum obtained by the fast Fourier Transformation (FFT)of the time domain waveform has a frequency resolution of 100MHz. The dependence of the signal to noise ratio (SNR)on the measurement time is also investigated

A multi-channel time-to-digital converter chip for drift chamber readout

International Nuclear Information System (INIS)

Santos, D.M.; Chau, A.; DeBusshere, D.; Dow, S.; Flasck, J.; Levi, M.; Kirsten, F.; Su, E.

1995-12-01

A complete, multi-channel, timing and amplitude measurement IC for use in drift chamber applications is described. By targeting specific resolutions, i.e. 6-bits of resolution for both time and amplitude, area and power can be minimized while achieving the proper level of measurement accuracy. Time is digitized using one eight channel TDC comprised of a delay locked loop and eight sets of latches and encoders. Amplitude (for dE/dx) is digitized using a dual-range FADC for each channel. Eight bits of dynamic range with six bits of accuracy are achieved with the dual-range. The timing and amplitude information is multiplexed into one DRAM (Dynamic Random Access Memory) trigger latency buffer. Interesting events are then transferred into an SRAM (Static Random Access Memory) readout buffer before the latency time has expired. The design has been optimized to achieve the requisite resolution using the smallest area and lowest power. The circuit has been implemented in a 0.8μ triple metal CMOS process. The TDC sub-element has been measured to have better than 135 ps time resolution and 35 ps jitter. The DRAM has a measured cycle time of 80 MHz

Time-resolved x-ray spectra from laser-generated high-density plasmas

Science.gov (United States)

Andiel, U.; Eidmann, Klaus; Witte, Klaus-Juergen

2001-04-01

We focused frequency doubled ultra short laser pulses on solid C, F, Na and Al targets, K-shell emission was systematically investigated by time resolved spectroscopy using a sub-ps streak camera. A large number of laser shots can be accumulated when triggering the camera with an Auston switch system at very high temporal precision. The system provides an outstanding time resolution of 1.7ps accumulating thousands of laser shots. The time duration of the He-(alpha) K-shell resonance lines was observed in the range of (2-4)ps and shows a decrease with the atomic number. The experimental results are well reproduced by hydro code simulations post processed with an atomic kinetics code.

Investigation of kinematic demixing of polymer blend deuterated polystyrene (d-PS) and polyvinylmethylether (PVME) with neutron small angle scattering

International Nuclear Information System (INIS)

Yee Madeira, H.T.

1989-03-01

The scope of this work is the investigation of the system PV ME/d-PS by small angle neutron scattering (SANS). The measurements were done with a pinhole-camera and a high resolution double crystal diffractometer and covered the resolution range from 10 -3 to 3x10 -2 A -1 and 2x10 -5 to 6x10 -4 A -1 respectively. As a basis for these investigations the phase diagram of a PVME/d-PS mixture was measured with SANS. The spinodal for different curve between stable and demixing region was obtained. For PVME with molecular weights M ω =60000 and d-PS with M ω =215103 the critical point is at the concentration Φ=0.2. From the spinodal and the structure factor the Flory-Huggins parameter Χ could be extracted as a function of temperature. It was found that Χ=0 for T comp =135 0 C and Χ is independent of the molecular weight within the accuracy of the data, thus Χ may be associated with a local interaction parameter. The scattering experiments for the determination of the spinodal confirmed the mean-field behaviour of the critical scattering which was earlier found by Herkt-Maetzky and Schelten. Further, the time dependence of the structure factor in the miscibility gap was investigated. From the structure factors, specially from the position Q max of their maxima, a characteristic length was extracted. (orig./RB) [de

Pressure Monitoring Using Hybrid fs/ps Rotational CARS

Science.gov (United States)

Kearney, Sean P.; Danehy, Paul M.

2015-01-01

We investigate the feasibility of gas-phase pressure measurements at kHz-rates using fs/ps rotational CARS. Femtosecond pump and Stokes pulses impulsively prepare a rotational Raman coherence, which is then probed by a high-energy 6-ps pulse introduced at a time delay from the Raman preparation. Rotational CARS spectra were recorded in N2 contained in a room-temperature gas cell for pressures from 0.1 to 3 atm and probe delays ranging from 10-330 ps. Using published self-broadened collisional linewidth data for N2, both the spectrally integrated coherence decay rate and the spectrally resolved decay were investigated as means for detecting pressure. Shot-averaged and single-laser-shot spectra were interrogated for pressure and the accuracy and precision as a function of probe delay and cell pressure are discussed. Single-shot measurement accuracies were within 0.1 to 6.5% when compared to a transducer values, while the precision was generally between 1% and 6% of measured pressure for probe delays of 200 ps or more, and better than 2% as the delay approached 300 ps. A byproduct of the pressure measurement is an independent but simultaneous measurement of the gas temperature.

Gain and time resolution of 45 μm thin Low Gain Avalanche Detectors before and after irradiation up to a fluence of 1015 neq/cm2

CERN Document Server

Lange, J; Cavallaro, E; Chytka, L; Davis, P.M; Flores, D; Förster, F; Grinstein, S; Hidalgo, S; Komarek, T; Kramberger, G; Mandić, I; Merlos, A; Nozka, L; Pellegrini, G; Quirion, D; Sykora, T; Physics

2018-01-01

The gain showed the expected decrease at a fixed voltage for a lower initial implantation dose, as well as for a higher fluence due to effective acceptor removal in the multiplication layer. Time resolutions below 30 ps were obtained at the highest applied voltages for both implantation doses before irradiation. Also after an intermediate fluence of 3 × 1014 neq/cm2, similar values were measured since a higher applicable reverse bias voltage could recover most of the pre-irradiation gain...

Fast time-resolved electrostatic force microscopy: Achieving sub-cycle time resolution

Energy Technology Data Exchange (ETDEWEB)

Karatay, Durmus U.; Harrison, Jeffrey S.; Glaz, Micah S.; Giridharagopal, Rajiv; Ginger, David S., E-mail: ginger@chem.washington.edu [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States)

2016-05-15

The ability to measure microsecond- and nanosecond-scale local dynamics below the diffraction limit with widely available atomic force microscopy hardware would enable new scientific studies in fields ranging from biology to semiconductor physics. However, commercially available scanning-probe instruments typically offer the ability to measure dynamics only on time scales of milliseconds to seconds. Here, we describe in detail the implementation of fast time-resolved electrostatic force microscopy using an oscillating cantilever as a means to measure fast local dynamics following a perturbation to a sample. We show how the phase of the oscillating cantilever relative to the perturbation event is critical to achieving reliable sub-cycle time resolution. We explore how noise affects the achievable time resolution and present empirical guidelines for reducing noise and optimizing experimental parameters. Specifically, we show that reducing the noise on the cantilever by using photothermal excitation instead of piezoacoustic excitation further improves time resolution. We demonstrate the discrimination of signal rise times with time constants as fast as 10 ns, and simultaneous data acquisition and analysis for dramatically improved image acquisition times.

Time-resolved interaction investigations of carbocyanine dyes and chlorophyll a in solution

International Nuclear Information System (INIS)

Feller, K.H.; Fassler, D.

1983-01-01

Using a Nd:YAG laser/streak camera system of 30 ps time resolution the quenching of the fluorescence of the carbocyanine dye ICC by chlorophyll a in methanolic solution was investigated. The fluorescence lifetime of ICC decreased within the chlorophyll concentration range 0 - 9x10 - 5 mol/l from 170 ps to 135 ps. The observed very effective fluorescence quenching process suggests that the formation of heteroaggregates from ICC and chlorophyll is responsible for the rapid energy transfer. (author)

iPS-Cinderella Story in Cell Biology

Directory of Open Access Journals (Sweden)

Editorial

2010-01-01

pluripotency and thus paving the way for use of iPS in humansIn this issue of JSRM we have Dr.Yukio Nakamura writing about Disease specific iPS cells which could serve as tools for understanding the underlying mechanisms of diseases which are less understood so far or which could be used as study models for drug discovery for disease therapy. Adding another positive futuristic step to this is the paper by Kataoka et al., who have shown that the iPS cells could be grown in a three dimensional scaffold in which their earlier studies have shown feasibility of a 200 time passaging of mouse foteal epithelial stem cells and neural stem cells. The strengths of Nakamura et al and that of Kataoka et al combined virtually, we see a much brighter picture for the iPS cells which might be in future much cleaner, be grown in an undifferentiated manner and be stored for long; then instead of cord blood storage all I dream is whenever a child is born we may simply custom make iPS for that child and cryopreserve it; May the dreams come true!Dr. Sheikh Riazuddin’s article about lin-c-kit+ BM-derived stem cells repair Infarcted Heart and Dr.Pravin Potdar’s article about Mesenchymal Stem Cells from adipose tissue give some basic understandings of the possible clinical translations. Happy reading!

Design and implementation of double oscillator time-to-digital converter using SFQ logic circuits

International Nuclear Information System (INIS)

Nishigai, T.; Ito, M.; Yoshikawa, N.; Fujimaki, A.; Terai, H.; Yorozu, S.

2005-01-01

We have designed, fabricated and tested a time-to-digital converter (TDC) using SFQ logic circuits. The proposed TDC consists of two sets of ring oscillators and binary counters, and a coincidence detector (CD), which detects the coincidence of the arrival of two SFQ pulses from two ring oscillators. The advantage of the proposed TDC is its simple circuit structure with wide measurement range. The time resolution of the proposed TDC is limited by the resolution of the CD, which is about 10 ps because it is made by an NDRO cell in this study. The circuits are implemented using NEC 2.5 kA/cm 2 Nb standard process and the CONNECT cell library. We have demonstrated the measurement of the propagation delay of a Josephson transmission line by the TDC with the time resolution of about 10 ps

Timing performance measurements of Si-PM-based LGSO phoswich detectors

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Kobayashi, Takahiro; Okumura, Satoshi; Yeom, Jung Yeol

2016-01-01

Since the timing resolution was significantly improved using silicon photomultipliers (Si-PMs) combined with fast scintillators, we expect that phoswich detectors will be used in future TOF-PET systems. However, no practical phoswich detector has been proposed for TOF-PET detectors. We conducted timing performance measurements of phoswich detectors comprised of two types of Ce-doped LGSO scintillators with different decay times coupled to Si-PMs and digitized the output signals using a high bandwidth digital oscilloscope. We prepared three types of LGSOs (LGSO-fast, LGSO-standard, and LGSO-slow) with different Ce concentrations. After measuring the decay time, the energy performance, and the timing performance of each LGSO, we conducted pulse shape analysis and timing resolution measurements for two versions of phoswich LGSOs: LGSO-standard/LGSO-fast and LGSO-slow/LGSO-fast combinations. The pulse shape spectra for a 10-mm-long crystal LGSO-slow/LGSO-fast combination showed good separation of the front and back crystals with a peak-to-valley ratio of 2.0. The timing resolutions for the 20-mm-long crystal LGSO-slow/LGSO-fast combination were ~300 ps FWHM. The timing resolutions for the phoswich LGSOs were slightly inferior than that measured with the individual LGSO fast, but the acquired timing resolution for the phoswich configuration, ~300 ps with a LGSO-slow/LGSO-fast combination, is adequate for TOF-PET systems. We conclude that LGSO phoswich detectors are promising for TOF-DOI-PET systems.

Gas Time-of-Flight Cherenkov Detector with Radiofrequency Phototube for FP420

International Nuclear Information System (INIS)

Margaryan, A.

2011-01-01

In this paper, the gas Cherenkov detector with radiofrequency phototube is considered as a fast-timing detector for FP420 project. The detector serves for precise Time-of-Flight measurements of forward going protons, capable of accurate vertex reconstruction and background rejection at high luminosities. The proposed technique is a high resolution (∼ 5 ps FWHM for a single proton), high rate (∼ MHz) and highly stable (less than 1 ps) timing technique capable to detect up to several tens events in a short (∼ 1 ns) time interval. (author)

Ultrafast time measurements by time-correlated single photon counting coupled with superconducting single photon detector

Energy Technology Data Exchange (ETDEWEB)

Shcheslavskiy, V., E-mail: vis@becker-hickl.de; Becker, W. [Becker & Hickl GmbH, Nahmitzer Damm 30, 12277 Berlin (Germany); Morozov, P.; Divochiy, A. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Vakhtomin, Yu. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991 (Russian Federation); Smirnov, K. [Scontel, Rossolimo St., 5/22-1, Moscow 119021 (Russian Federation); Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991 (Russian Federation); National Research University Higher School of Economics, 20 Myasnitskaya St., Moscow 101000 (Russian Federation)

2016-05-15

Time resolution is one of the main characteristics of the single photon detectors besides quantum efficiency and dark count rate. We demonstrate here an ultrafast time-correlated single photon counting (TCSPC) setup consisting of a newly developed single photon counting board SPC-150NX and a superconducting NbN single photon detector with a sensitive area of 7 × 7 μm. The combination delivers a record instrument response function with a full width at half maximum of 17.8 ps and system quantum efficiency ∼15% at wavelength of 1560 nm. A calculation of the root mean square value of the timing jitter for channels with counts more than 1% of the peak value yielded about 7.6 ps. The setup has also good timing stability of the detector–TCSPC board.

High resolution time integration for SN radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2009-01-01

First-order, second-order, and high resolution time discretization schemes are implemented and studied for the discrete ordinates (S N ) equations. The high resolution method employs a rate of convergence better than first-order, but also suppresses artificial oscillations introduced by second-order schemes in hyperbolic partial differential equations. The high resolution method achieves these properties by nonlinearly adapting the time stencil to use a first-order method in regions where oscillations could be created. We employ a quasi-linear solution scheme to solve the nonlinear equations that arise from the high resolution method. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second-order and high resolution converged to the same solution as the first-order with better convergence rates. High resolution is more accurate than first-order and matches or exceeds the second-order method

Studies of SiPM photosensors for time-of-flight detectors within PANDA at FAIR

International Nuclear Information System (INIS)

Gruber, L.

2014-01-01

The PANDA experiment at FAIR is a planned particle physics experiment dedicated to strong interaction studies using proton-antiproton annihilations. The PANDA time-of-flight (TOF) system is foreseen as a Scintillator Tile (SciTil) Hodoscope, which will deliver valuable input for event timing and particle identification. The proposed detector is based on small plastic scintillator tiles with a size of about 30 x 30 x 5 mm 3 , which are read-out with directly attached Silicon Photomultipliers (SiPMs). The whole system is composed of 5760 scintillator tiles and twice the number of photodetectors, covering an area of about 5.2 m 2 in total. The requirements for the detector are a time resolution in the order of 100 ps sigma and a minimum use of material due to the limited space inside the PANDA spectrometer. SiPMs are extremely versatile photodetectors which tend to successively replace the ordinary vacuum Photomultiplier Tubes (PMTs) in many of the photosensing demands ranging from particle physics to medical imaging. Due to many advantages like good time resolution, high photon detection efficiency (PDE), compactness, low operating voltage, radiation hardness, low cost and, in contrast to PMTs, insensitivity to magnetic fields, SiPMs are well suited for applications in high energy physics like PANDA. Recently, Philips invented the first fully digital SiPM (DPC), which allows to exploit the quasi digital nature of single photon detection. The analog and digital SiPM, respectively, are the main detector technologies used within this work. This thesis describes a detailed study of SiPM properties in order to characterize the new devices and get a profound understanding of their functionality. The characterization studies have been carried out using various experimental setups employing pulsed pico- and femtosecond lasers. With regard to applications in high energy physics experiments, e.g. the PANDA TOF system, parameters like SiPM gain, dark count rate, time resolution

Synthesis and Characterization of the Rubidium Thiophosphate Rb 6 (PS 5 )(P 2 S 10 ) and the Rubidium Silver Thiophosphates Rb 2 AgPS 4 , RbAg 5 (PS 4 ) 2 and Rb 3 Ag 9 (PS 4 ) 4

KAUST Repository

Alahmary, Fatimah S.; Davaasuren, Bambar; Khanderi, Jayaprakash; Rothenberger, Alexander

2016-01-01

The metal thiophosphates Rb2AgPS4 (2), RbAg5(PS4)2 (3), and Rb3Ag9(PS4)4 (4) were synthesized by stoichiometric reactions, whereas Rb6(PS5)(P2S10) (1) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P21

Frontend electronics for high-precision single photo-electron timing using FPGA-TDCs

Energy Technology Data Exchange (ETDEWEB)

Cardinali, M., E-mail: cardinal@kph.uni-mainz.de [Institut für Kernphysik, Johannes Gutenberg-University Mainz, Mainz (Germany); Helmholtz Institut Mainz, Mainz (Germany); Dzyhgadlo, R.; Gerhardt, A.; Götzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Ugur, C.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); Dodokhov, V.Kh. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Britting, A. [Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); and others

2014-12-01

The next generation of high-luminosity experiments requires excellent particle identification detectors which calls for Imaging Cherenkov counters with fast electronics to cope with the expected hit rates. A Barrel DIRC will be used in the central region of the Target Spectrometer of the planned PANDA experiment at FAIR. A single photo-electron timing resolution of better than 100 ps is required by the Barrel DIRC to disentangle the complicated patterns created on the image plane. R and D studies have been performed to provide a design based on the TRB3 readout using FPGA-TDCs with a precision better than 20 ps RMS and custom frontend electronics with high-bandwidth pre-amplifiers and fast discriminators. The discriminators also provide time-over-threshold information thus enabling walk corrections to improve the timing resolution. Two types of frontend electronics cards optimised for reading out 64-channel PHOTONIS Planacon MCP-PMTs were tested: one based on the NINO ASIC and the other, called PADIWA, on FPGA discriminators. Promising results were obtained in a full characterisation using a fast laser setup and in a test experiment at MAMI, Mainz, with a small scale DIRC prototype. - Highlights: • Frontend electronics for Cherenkov detectors have been developed. • FPGA-TDCs have been used for high precision timing. • Time over threshold has been utilised for walk correction. • Single photo-electron timing resolution less than 100 ps has been achieved.

PS3 CELL Development for Scientific Computation and Research

Science.gov (United States)

Christiansen, M.; Sevre, E.; Wang, S. M.; Yuen, D. A.; Liu, S.; Lyness, M. D.; Broten, M.

2007-12-01

The Cell processor is one of the most powerful processors on the market, and researchers in the earth sciences may find its parallel architecture to be very useful. A cell processor, with 7 cores, can easily be obtained for experimentation by purchasing a PlayStation 3 (PS3) and installing linux and the IBM SDK. Each core of the PS3 is capable of 25 GFLOPS giving a potential limit of 150 GFLOPS when using all 6 SPUs (synergistic processing units) by using vectorized algorithms. We have used the Cell's computational power to create a program which takes simulated tsunami datasets, parses them, and returns a colorized height field image using ray casting techniques. As expected, the time required to create an image is inversely proportional to the number of SPUs used. We believe that this trend will continue when multiple PS3s are chained using OpenMP functionality and are in the process of researching this. By using the Cell to visualize tsunami data, we have found that its greatest feature is its power. This fact entwines well with the needs of the scientific community where the limiting factor is time. Any algorithm, such as the heat equation, that can be subdivided into multiple parts can take advantage of the PS3 Cell's ability to split the computations across the 6 SPUs reducing required run time by one sixth. Further vectorization of the code can allow for 4 simultanious floating point operations by using the SIMD (single instruction multiple data) capabilities of the SPU increasing efficiency 24 times.

A method for generating high resolution satellite image time series

Science.gov (United States)

Guo, Tao

2014-10-01

There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

A&T Sector Note on the PS transverse feedback

CERN Document Server

Coly, Marcel; Blas, Alfred; Sterbini, Guido; CERN. Geneva. ATS Department

2017-01-01

In a particle accelerator, several contributions can degrade the beam quality and particularly the beam transverse emittance. In this document we will describe a system used in the CERN Proton Synchrotron (PS) to cope with the injection steering errors and the transverse instabilities: the PS transverse feedback (PS TFB). As time progresses, this system is also being used for other purpose, to increase in a controlled way the beam transverse emittance and to excite the beam for the Multi-Turn-Extraction (MTE). In 2016, it has been successfully used on some operational beams to damp injection oscillations. This allowed to test the reliability of the system for its operational deployment. A piquet service is available in case of problem.

High-resolution fine mapping of ps-2, a mutated gene conferring functional male sterility in tomato due to non-dehiscent anthers

NARCIS (Netherlands)

Gorguet, B.J.M.; Schipper, E.H.; Heusden, van A.W.; Lindhout, P.

2006-01-01

Functional male sterility is an important trait for the production of hybrid seeds. Among the genes coding for functional male sterility in tomato is the positional sterility gene ps-2. ps-2 is monogenic recessive, confers non-dehiscent anthers and is the most suitable for practical uses. In order

Single Photon Counting Large Format Imaging Sensors with High Spatial and Temporal Resolution

Science.gov (United States)

Siegmund, O. H. W.; Ertley, C.; Vallerga, J. V.; Cremer, T.; Craven, C. A.; Lyashenko, A.; Minot, M. J.

High time resolution astronomical and remote sensing applications have been addressed with microchannel plate based imaging, photon time tagging detector sealed tube schemes. These are being realized with the advent of cross strip readout techniques with high performance encoding electronics and atomic layer deposited (ALD) microchannel plate technologies. Sealed tube devices up to 20 cm square have now been successfully implemented with sub nanosecond timing and imaging. The objective is to provide sensors with large areas (25 cm2 to 400 cm2) with spatial resolutions of 5 MHz and event timing accuracy of 100 ps. High-performance ASIC versions of these electronics are in development with better event rate, power and mass suitable for spaceflight instruments.

The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

Energy Technology Data Exchange (ETDEWEB)

Frenje, J. A., E-mail: jfrenje@psfc.mit.edu; Wink, C. W.; Gatu Johnson, M.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hilsabeck, T. J.; Kilkenny, J. D. [General Atomics, San Diego, California 92186 (United States); Bell, P.; Bionta, R.; Cerjan, C. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2016-11-15

The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T{sub i}), yield (Y{sub n}), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10{sup 16}. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF).

Science.gov (United States)

Frenje, J A; Hilsabeck, T J; Wink, C W; Bell, P; Bionta, R; Cerjan, C; Gatu Johnson, M; Kilkenny, J D; Li, C K; Séguin, F H; Petrasso, R D

2016-11-01

The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T i ), yield (Y n ), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10 16 . At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

PS Booster - Festive colloquium

CERN Multimedia

2012-01-01

A festive colloquium will be held to celebrate the 40th anniversary of the PS Booster on Friday, 28 September at 2 p.m. in the CERN council chamber. The meeting will be open to everybody. Read more on the PS Booster in the CERN Bulletin and in the CERN Courier.

Symmetry of dipositronium Ps2

International Nuclear Information System (INIS)

Schrader, D.M.

2004-01-01

We work out the complete symmetry and spin problem for diatomic positronium Ps 2 for the ground and singly excited states of zero orbital angular momentum. The general form of the wave function for each state is given, with due regard to charge conjugation parity. Annihilation rates are discussed, and correlations to dissociation products are deduced. We indicate how the approach is extensible to larger aggregates: i.e., PsPs n , n>2

The STiC ASIC. High precision timing with silicon photomultipliers

International Nuclear Information System (INIS)

Harion, Tobias

2015-01-01

In recent years, Silicon Photomultipliers are being increasingly used for Time of Flight measurements in particle detectors. To utilize the high intrinsic time resolution of these sensors in detector systems, the development of specialized, highly integrated readout electronics is required. In this thesis, a mixed-signal application specific integrated circuit, named STiC, has been developed, characterized and integrated in a detector system. STiC has been specifically designed for high precision timing measurements with SiPMs, and is in particular dedicated to the EndoTOFPET-US project, which aims to achieve a coincidence time resolution of 200 ps FWHM and an energy resolution of less than 20% in an endoscopic positron emission tomography system. The chip integrates 64 high precision readout channels for SiPMs together with a digital core logic to process, store and transfer the recorded events to a data acquisition system. The performance of the chip has been validated in coincidence measurements using detector modules consisting of 3.1 x 3.1 x 15 mm 3 LYSO crystals coupled to Silicon Photomultipliers from Hamamatsu. The measurements show an energy resolution of 15% FWHM for the detection of 511 keV photons. A coincidence time resolution of 213 ps FWHM has been measured, which is among the best resolution values achieved to date with this detector topology. STiC has been integrated in the EndoTOFPET-US detector system and has been chosen as the baseline design for the readout of SiPM sensors in the Mu3e experiment.

A time-to-amplitude converter with constant fraction timing discriminators for short time interval measurements

International Nuclear Information System (INIS)

Kostamovaara, J.; Myllylae, R.

1985-01-01

The construction and the performance of a time-to-amplitude converter equipped with constant fraction discriminators is described. The TAC consists of digital and analog parts which are constructed on two printed circuit boards, both of which are located in a single width NIM module. The dead time of the TAC for a start pulse which is not followed by a stop pulse within the time range of the device (proportional100 ns) is only proportional100 ns, which enables one to avoid counting rate saturation even with a high random input signal rate. The differential and integral nonlinearities of the TAC are better than +-1.5% and 0.05%, respectively. The resolution for input timing pulses of constant shape is 20 ps (fwhm), and less than 10 ps (fwhm) with a modification in the digital part. The walk error of the constant fraction timing discriminators is presented and various parameters affecting it are discussed. The effect of the various disturbances in linearity caused by the fast ECL logic and their minimization are also discussed. The time-to-amplitude converter has been used in positron lifetime studies and for laser range finding. (orig.)

Time response of fast-gated microchannel plates used as x-ray detectors

International Nuclear Information System (INIS)

Turner, R.E.; Bell, P.; Hanks, R.; Kilkenny, J.D.; Landen, N.; Power, G.; Wiedwald, J.; Meier, M.

1990-01-01

We report measurements of the time response of fast-gated, micro- channel plate (MCP) detectors, using a <10 ps pulsewidth ultra-violet laser and an electronic sampling system to measure time resolutions to better than 25 ps. The results show that framing times of less than 100 ps are attainable with high gain. The data is compared to a Monte Carlo calculation, which shows good agreement. We also measured the relative sensitivity as a function of DC bias, and saturation effects for large signal inputs. In part B, we briefly describe an electrical ''time-of-flight'' technique, which we have used to measure the response time of a fast-gated microchannel plate (MCP). Thinner MCP's than previously used have been tested, and, as expected, show fast gating times and smaller electron multiplication. A preliminary design for an x-ray pinhole camera, using a thin MCP, is presented. 7 refs., 6 figs

Search for an optimum time response of spark counters

International Nuclear Information System (INIS)

Devismes, A.; Finck, Ch.; Kress, T.; Gobbi, A.; Eschke, J.; Herrmann, N.; Hildenbrand, K.D.; Koczon, P.; Petrovici, M.

2002-01-01

A spark counter of the type developed by Pestov has been tested with the aim of searching for an optimum time response function, changing voltage, content of noble and quencher gases, pressure and energy-loss. Replacing the usual argon by neon has brought an improvement of the resolution and a significant reduction of tails in the time response function. It has been proven that a counter as long as 90 cm can deliver, using neon gas mixture, a time resolution σ<60 ps with about 1% absolute tail and an efficiency of about 90%

On the timing performance of thin planar silicon sensors

Science.gov (United States)

Akchurin, N.; Ciriolo, V.; Currás, E.; Damgov, J.; Fernández, M.; Gallrapp, C.; Gray, L.; Junkes, A.; Mannelli, M.; Martin Kwok, K. H.; Meridiani, P.; Moll, M.; Nourbakhsh, S.; Pigazzini, S.; Scharf, C.; Silva, P.; Steinbrueck, G.; de Fatis, T. Tabarelli; Vila, I.

2017-07-01

We report on the signal timing capabilities of thin silicon sensors when traversed by multiple simultaneous minimum ionizing particles (MIP). Three different planar sensors, with depletion thicknesses 133, 211, and 285 μm, have been exposed to high energy muons and electrons at CERN. We describe signal shape and timing resolution measurements as well as the response of these devices as a function of the multiplicity of MIPs. We compare these measurements to simulations where possible. We achieve better than 20 ps timing resolution for signals larger than a few tens of MIPs.

Development of high-resolution detector module with depth of interaction identification for positron emission tomography

International Nuclear Information System (INIS)

Niknejad, Tahereh; Pizzichemi, Marco; Stringhini, Gianluca; Auffray, Etiennette; Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino; Ferramacho, Luis; Lecoq, Paul; Leong, Carlos; Paganoni, Marco; Rolo, Manuel; Silva, Rui; Silveira, Miguel; Tavernier, Stefaan; Varela, Joao; Zorraquino, Carlos

2017-01-01

We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm"3 matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

Development of high-resolution detector module with depth of interaction identification for positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Niknejad, Tahereh, E-mail: tniknejad@lip.pt [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Pizzichemi, Marco [University of Milano-Bicocca (Italy); Stringhini, Gianluca [University of Milano-Bicocca (Italy); CERN, Geneve (Switzerland); Auffray, Etiennette [CERN, Geneve (Switzerland); Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Ferramacho, Luis [PETsys Electronics, Oeiras (Portugal); Lecoq, Paul [CERN, Geneve (Switzerland); Leong, Carlos [PETsys Electronics, Oeiras (Portugal); Paganoni, Marco [University of Milano-Bicocca (Italy); Rolo, Manuel [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); INFN, Turin (Italy); Silva, Rui [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Silveira, Miguel [PETsys Electronics, Oeiras (Portugal); Tavernier, Stefaan [PETsys Electronics, Oeiras (Portugal); Vrije Universiteit Brussel (Belgium); Varela, Joao [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); CERN, Geneve (Switzerland); Zorraquino, Carlos [Biomedical Image Technologies Lab, Universidad Politécnica de Madrid (Spain); CIBER-BBN, Universidad Politécnica de Madrid (Spain)

2017-02-11

We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm{sup 3} matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

Effect of exposure time and image resolution on fractal dimension

International Nuclear Information System (INIS)

An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won; Kim, Jong Dae

2002-01-01

To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

Inhibition of Ps Formation in Benzene and Cyclohexane by CH3CI and CH3Br

DEFF Research Database (Denmark)

Wikander, G.; Mogensen, O. E.; Pedersen, Niels Jørgen

1983-01-01

Positron-annihilation lifetime spectra have been measured for mixtures of CH3Cl and CH3Br in cyclohexane and of CH3Cl in benzene. The ortho-positronium (Ps) yield decreased monotonically from 38% and 43% in cyclohexane and benzene respectively to 11% in pure CH3Cl and 6% in pure CH3Br. The strength......− anions to form Ps. while it forms a bound state with the halides. X−. CH3Cl was a roughly three times weaker Ps inhibitor in benzene than in cyclohexane, which shows that CH3Cl− does not dechlorinate in times comparable to or shorter than 400–500 ps in benzene. An improved model for the explanation of Ps...

Psychometric properties of the OARSI/OMERACT osteoarthritis pain and functional impairment scales: ICOAP, KOOS-PS and HOOS-PS.

Science.gov (United States)

Ruyssen-Witrand, A; Fernandez-Lopez, C J; Gossec, L; Anract, P; Courpied, J P; Dougados, M

2011-01-01

To evaluate the psychometric properties of the OARSI-OMERACT questionnaires in comparison to the existing validated scales. Consecutive hip or knee osteoarthritis patients consulting in an orthopedic department were enrolled in the study. Data collected were pain using the Intermittent and Constant Osteoarthritis Pain (ICOAP), a Numeric Rating Scale (NRS), the Western Ontario McMaster Universities' Osteoarthritis Index (WOMAC) pain subscale, the Lequesne pain subscale; functional impairment using the Knee disability and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS), the Hip disability and Osteoarthritis Outcome Score-Physical Function Shortform (HOOS-PS), a NRS, the WOMAC function sub-scale, the Lequesne function subscale. Validity was assessed by calculating the Spearman's correlation coefficient between all the scales. Reliability was assessed in out-patients with stable disease comparing the data collected within 2 weeks using the intra-class correlation coefficient (ICC). Responsiveness was assessed on the data from hospitalised patients prior to and 12 weeks after a total joint replacement (TJR) using the standardised response mean. Three hundred patients (mean age=68 years, females=62%, hip OA=57%) were included. There was a moderate to good correlation between ICOAP, KOOS-PS, HOOS-PS and the WOMAC, NRS and Lequesne scales. Reliability of the ICOAP hip OA HOOS-PS and KOOS-PS was good (ICC range 0.80-0.81) whereas it was moderate for knee ICOAP (ICC=0.65). Responsiveness of the ICOAP, KOOS-PS and HOOS-PS 12 weeks after TJR was comparable to responsiveness of other scales (SRM range: 0.54-1.82). The psychometric properties of the ICOAP, KOOS-PS and HOOS-PS were comparable to those of the WOMAC, Lequesne and NRS.

Expectation values of the e+PsH system

International Nuclear Information System (INIS)

Zhang, J.-Y.; Mitroy, J.

2007-01-01

Close to converged energies and expectation values for e + PsH are computed using a ground-state wave function consisting of 1500 explicitly correlated Gaussians. The best estimate of the e + PsH ∞ energy was -0.810 254 hartrees, which has a binding energy of 0.021 057 hartrees against dissociation into e + +PsH. The 2γ annihilation rate was 2.7508x10 9 s -1 . Binding energies and annihilation rates are also given for the different finite-mass variants of e + PsH. Comparisons between expectation values for e + PsH and PsH provide compelling evidence that the e + PsH ground state can be regarded as consisting of a weakly bound positron orbiting the PsH ground state

The development of a gas-filled time-of-flight detector

International Nuclear Information System (INIS)

Guan Yongjing; He Ming; Ruan Xiangdong; Wang Huijuan; Wu Shaoyong; Dong Kejun; Lin Min; Yuan Jian; Jiang Shan

2007-01-01

A gas-filled time-of-flight (GF-TOF) detector system for isobaric identification has been developed at the AMS facility of the China Institute of Atomic Energy (CIAE). The newly built GF-TOF detector was tested by using a 36 Cl standard sample ( 36 Cl/Cl = 2.88 x 10 -11 ) with the 36 Cl ion energies of 64, 49 and 33 MeV. Time resolutions of 350 ps, 580 ps and 920 ps were obtained for 64, 49 and 33 MeV 36 S, respectively, without gas. 36 Cl and 36 S particles were successfully separated in the TOF spectra from the GF-TOF detector at the three different incident energies. The dependence of time resolution and separation power of GF-TOF method on the incidence energy and the residual energy is discussed. The comparison of separation power for isobars between the GF-TOF method and the ΔE-E method is described. A combination of GF-TOF method and ΔE-E method may further improve the separation power for isobars. The results show that the sensitivity for 36 Cl AMS measurements is 10 -14 at the energy of 33 MeV. Some results obtained with the GF-TOF method are given

Modelling of Ne-like copper X-ray laser driven by 1.2 ps short pulse and 280 ps background pulse configuration

International Nuclear Information System (INIS)

Demir, A.; Kenar, N.; Goktas, H.; Tallents, G.J.

2004-01-01

Detailed simulations of Ne-like Cu x-ray laser are undertaken using the EHYBRID code. The atomic physics data are obtained using the Cowan code. The optimization calculations are performed in terms of the intensity of background and the time separation between the background and the short pulse. The optimum value is obtained for the conditions of a Nd:glass laser with 1.2 ps pulse at 4.4 x 10 15 W cm -2 irradiance pumping a plasma pre-formed by a 280 ps duration pulse at 5.4 x 10 12 W cm -2 with peak-to-peak pulse separation set at 300 ps. X-ray resonance lines between 6 A and 15 A emitted from copper plasmas have been simulated. Free-free and free-bound emission from the Si-, Al-, Mg-, Na-, Ne- and F-like ions is calculated in the simulation. (author)

An investigation into radiosensitizer mechanisms using o-Ps lifetime measurements

International Nuclear Information System (INIS)

Beling, C.D.; Smith, F.A.

1982-01-01

Lifetime measurements have been made in a number of radiosensitizer solutions as a function of both concentration and temperature. The o-Ps yields, which were corrected for chemical quenching, showed that these compounds are strong Ps inhibitors. The temperature dependence of the yields in Misonidazole/water and Misonidazole/ethanol solutions may be associated either with the different electron solvation times in the two solvents, or with changes in electron mobility. (Auth.)

Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

Science.gov (United States)

Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C

2015-02-01

We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

Sequence control of phase separation and dewetting in PS/PVME blend thin films by changing molecular weight of PS.

Science.gov (United States)

Xia, Tian; Qin, Yaping; Huang, Yajiang; Huang, Ting; Xu, Jianhui; Li, Youbing

2016-11-28

The morphology evolution mechanism of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films with different PS molecular weights (M w ) was studied. It was found that the morphology evolution was closely related to the molecular weight asymmetry between PS and PVME. In the film where M w (PS) ≈ M w (PVME), dewetting happened at the interface between the bottom layer and substrate after SD phase separation. While in the film where M w (PS) > M w (PVME), dewetting happened at the interface between the middle PS/PVME blend layer and bottom PVME layer near the substrate prior to phase separation. The different sequences of phase separation and dewetting and different interface for dewetting occurrence were studied by regarding the competitive effects of viscoelasticity contrast between polymer components and preferential wetting between PVME and the substrate. The viscoelastic nature of the PS component played a crucial role in the sequence of phase separation and dewetting.

Signal encoding method for a time-of-flight PET detector using a silicon photomultiplier array

Science.gov (United States)

Kwon, Sun Il; Lee, Jae Sung

2014-10-01

The silicon photomultiplier (SiPM) is a promising photosensor for magnetic resonance (MR) compatible time-of-flight (TOF) positron emission tomography (PET) scanners. The compact size of the SiPM allows direct one-to-one coupling between the scintillation crystal and the photosensor, yielding better timing and energy resolutions than the light sharing methods that have to be used in photomultiplier tube (PMT) PET systems. However, the one-to-one coupling scheme requires a huge volume of readout and processing electronics if no electric signal multiplexing or encoding scheme is properly applied. In this paper, we develop an electric signal encoding scheme for SiPM array based TOF PET detector blocks with the aim of reducing the complexity and volume of the signal readout and processing electronics. In an M×N SiPM array, the output signal of each channel in the SiPM array is divided into two signal lines. These output lines are then tied together in row and column lines. The row and column signals are used to measure the energy and timing information (or vice versa) of each incident gamma-ray event, respectively. Each SiPM channel was directly coupled to a 3×3×20 mm3 LGSO crystal. The reference detector, which was used to measure timing, consisted of an R9800 PMT and a 4×4×10 mm3 LYSO crystal and had a single time resolution of ~200 ps (FWHM). Leading edge discriminators were used to determine coincident events. Dedicated front-end electronics were developed, and the timing and energy resolutions of SiPM arrays with different array sizes (4×4, 8×8, and 12×12) were compared. Breakdown voltage of each SiPM channel was measured using energy spectra within various bias voltages. Coincidence events were measured using a 22Na point source. The average coincidence time resolution of 4×4, 8×8, and 12×12 SiPM arrays were 316 ps, 320 ps, and 335 ps (FWHM), respectively. The energy resolution of 4×4, 8×8, and 12×12 SiPM arrays were 11.8%, 12.5%, and 12.8% (FWHM

Developing a structure-function model for the cryptophyte phycoerythrin 545 using ultrahigh resolution crystallography and ultrafast laser spectroscopy.

Science.gov (United States)

Doust, Alexander B; Marai, Christopher N J; Harrop, Stephen J; Wilk, Krystyna E; Curmi, Paul M G; Scholes, Gregory D

2004-11-12

Cryptophyte algae differ from cyanobacteria and red algae in the architecture of their photosynthetic light harvesting systems, even though all three are evolutionarily related. Central to cryptophyte light harvesting is the soluble antenna protein phycoerythrin 545 (PE545). The ultrahigh resolution crystal structure of PE545, isolated from a unicellular cryptophyte Rhodomonas CS24, is reported at both 1.1A and 0.97A resolution, revealing details of the conformation and environments of the chromophores. Absorption, emission and polarized steady state spectroscopy (298K, 77K), as well as ultrafast (20fs time resolution) measurements of population dynamics are reported. Coupled with complementary quantum chemical calculations of electronic transitions of the bilins, these enable assignment of spectral absorption characteristics to each chromophore in the structure. Spectral differences between the tetrapyrrole pigments due to chemical differences between bilins, as well as their binding and interaction with the local protein environment are described. Based on these assignments, and considering customized optical properties such as strong coupling, a model for light harvesting by PE545 is developed which explains the fast, directional harvesting of excitation energy. The excitation energy is funnelled from four peripheral pigments (beta158,beta82) into a central chromophore dimer (beta50/beta61) in approximately 1ps. Those chromophores, in turn, transfer the excitation energy to the red absorbing molecules located at the periphery of the complex in approximately 4ps. A final resonance energy transfer step sensitizes just one of the alpha19 bilins on a time scale of 22ps. Furthermore, it is concluded that binding of PE545 to the thylakoid membrane is not essential for efficient energy transfer to the integral membrane chlorophyll a-containing complexes associated with PS-II.

Sub-nanosecond time-of-flight for segmented silicon detectors

International Nuclear Information System (INIS)

Souza, R.T. de; Alexander, A.; Brown, K.; Floyd, B.; Gosser, Z.Q.; Hudan, S.; Poehlman, J.; Rudolph, M.J.

2011-01-01

Development of a multichannel time-of-flight system for readout of a segmented, ion-passivated, ion-implanted silicon detector is described. This system provides sub-nanosecond resolution (δt∼370ps) even for low energy α particles which deposit E≤7.687MeV in the detector.

Electron Spin Resonance studies on PS, PP and PS/PP blends under gamma irradiation

International Nuclear Information System (INIS)

Reyes, J.; Claro, M.; Albano, C.; Venezuela Central University, Caracas; Moronta, D.

2002-01-01

Complete text of publication follows. Electron Spin Resonance (ESR) studies on Polystyrene (PS), Polypropylene (PP) and their mixtures at compositions of 80/20 with and without a compatibilizer (SBS in block), 7.5 wt.%, irradiated with gamma rays from a Cobalt-60 source with a dose rate of 4.8 KGy/h at integral doses of radiation of 10, 25, 50, 60, 70, 400, 800 and 1300 KGy in the presence of air and at room temperature (RT) are reported. The dependence of resonance line width, Hpp; resonance line shapes K, and radical concentration, S, with the integral dose of irradiation is investigated. The nature of the free radicals after ten days of air storage is discussed. The free radical concentration, the double integral of the resonance line, S, has been estimated at room temperature, RT, for a group of single lines, characterized by the same giromagnetic, g, value by direct numerical double integration. In the samples studied no spectrum of 0 kGy of integral dose was observed. The concentration of radicals, S, observed when the integral radiation doses was increased, presents a maximum value in the PP samples at high doses (70-1300 kGy) and minimum values in the PS samples with the same doses. This shows that the PP degrades at a faster rate than the PS, owing to the presence of the bencenic ring in the latter. In the PS/PP mixtures studied with and without compatibilizer, the values of the radical concentration is found between the observed values in the homopolymers, being closer to the PS, which might imply that the presence of PS decays the degradation process of the PP in the mixture

Cs0.49NbPS6

Directory of Open Access Journals (Sweden)

Hoseop Yun

2011-01-01

Full Text Available The quaternary thiophosphate, Cs0.49NbPS6, caesium hexathioniobiophosphate(V, has been synthesized by the reactive halide flux method. The title compound is isotypic with Rb0.46TaPS6 and is made up of a bicapped trigonal–biprismatic [Nb2S12] unit and a tetrahedral [PS4] group. The [Nb2S12] units linked by the [PS4] tetrahedra form infinite chains, yielding a three-dimensional network with rather large van der Waals gaps along the c axis in which the disordered Cs+ ions reside. The electrons released by the Cs atoms are transferred to the pairwise niobium metal site and there are substantial intermetallic Nb—Nb bonding interactions. This leads to a significant decrease of the intermetallic distance in the title compound compared to that in TaPS6. The classical charge balance of the title compound may be represented as [Cs+]0.49[Nb4.51+][P5+][S2−]4[S22−].

Sensitivity encoded silicon photomultiplier—a new sensor for high-resolution PET-MRI

International Nuclear Information System (INIS)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-01-01

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm 3 . For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

Sensitivity encoded silicon photomultiplier—a new sensor for high-resolution PET-MRI

Science.gov (United States)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-01

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm3. For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

Sensitivity encoded silicon photomultiplier--a new sensor for high-resolution PET-MRI.

Science.gov (United States)

Schulz, Volkmar; Berker, Yannick; Berneking, Arne; Omidvari, Negar; Kiessling, Fabian; Gola, Alberto; Piemonte, Claudio

2013-07-21

Detectors for simultaneous positron emission tomography and magnetic resonance imaging in particular with sub-mm spatial resolution are commonly composed of scintillator crystal arrays, readout via arrays of solid state sensors, such as avalanche photo diodes (APDs) or silicon photomultipliers (SiPMs). Usually a light guide between the crystals and the sensor is used to enable the identification of crystals which are smaller than the sensor elements. However, this complicates crystal identification at the gaps and edges of the sensor arrays. A solution is to use as many sensors as crystals with a direct coupling, which unfortunately increases the complexity and power consumption of the readout electronics. Since 1997, position-sensitive APDs have been successfully used to identify sub-mm crystals. Unfortunately, these devices show a limitation in their time resolution and a degradation of spatial resolution when placed in higher magnetic fields. To overcome these limitations, this paper presents a new sensor concept that extends conventional SiPMs by adding position information via the spatial encoding of the channel sensitivity. The concept allows a direct coupling of high-resolution crystal arrays to the sensor with a reduced amount of readout channels. The theory of sensitivity encoding is detailed and linked to compressed sensing to compute unique sparse solutions. Two devices have been designed using one- and two-dimensional linear sensitivity encoding with eight and four readout channels, respectively. Flood histograms of both devices show the capability to precisely identify all 4 × 4 LYSO crystals with dimensions of 0.93 × 0.93 × 10 mm(3). For these crystals, the energy and time resolution (MV ± SD) of the devices with one (two)-dimensional encoding have been measured to be 12.3 · (1 ± 0.047)% (13.7 · (1 ± 0.047)%) around 511 keV with a paired coincidence time resolution (full width at half maximum) of 462 · (1 ± 0.054) ps (452 · (1 ± 0

High resolution time integration for Sn radiation transport

International Nuclear Information System (INIS)

Thoreson, Greg; McClarren, Ryan G.; Chang, Jae H.

2008-01-01

First order, second order and high resolution time discretization schemes are implemented and studied for the S n equations. The high resolution method employs a rate of convergence better than first order, but also suppresses artificial oscillations introduced by second order schemes in hyperbolic differential equations. All three methods were compared for accuracy and convergence rates. For non-absorbing problems, both second order and high resolution converged to the same solution as the first order with better convergence rates. High resolution is more accurate than first order and matches or exceeds the second order method. (authors)

SPS and PS Experiments Committee

CERN Multimedia

CERN. Geneva

2004-01-01

OPEN SESSION: 09:00 Status report of NA58 / COMPASS: A. Magnon 09:40 Status report of PS212 / DIRAC: L. Tausher 10:10 PS212 / DIRAC Addendum: L. Nemenov CLOSED SESSION on Tuesday, 27 April 2004 after the open session, Main Building, 6th floor conference room

A high resolution TOF-PET concept with axial geometry and digital SiPM readout

CERN Document Server

Casella, C; Joram, C; Schneider, T

2014-01-01

The axial arrangement of long scintillation crystals is a promising concept in PET instrumentation to address the need for optimized resolution and sensitivity. Individual crystal readout and arrays of wavelength shifter strips placed orthogonally to the crystals lead to a 3D-detection of the annihilations photons. A fully operational demonstrator scanner, developed by the AX-PET collaboration, proved the potential of this concept in terms of energy and spatial resolution as well as sensitivity. This paper describes a feasibility study, performed on axial prototype detector modules with 100 mm long LYSO crystals, read out by the novel digital Silicon Photomultipliers (dSiPM) from Philips. With their highly integrated readout electronics and excellent intrinsic time resolution, dSiPMs allow for compact, axial detector modules which may extend the potential of the axial PET concept by time of fl ight capabilities (TOF-PET). A coincidence time resolution of 211 ps (FWHM) was achieved in the coincidence of two ax...

Psühhodramaatikud annavad Pärnus eksami

Index Scriptorium Estoniae

2008-01-01

29. maist kuni 1. juunini kestab Pärnus psühhodraama konverents "Geeniuste kohtumine", kus rahvusvahelise koolituse läbinud annavad eksami. Ruuda Palmquist on psühhodraama kui teadusharu rajajaid Eestis. Pärnus on kohal Rootsi Moreno Instituudi juhataja, psühhodraama lavastaja Marc Treadwell

LEADIR-PS: providing unprecedented SMR safety and economics

Energy Technology Data Exchange (ETDEWEB)

Hart, R.S., E-mail: N2i2@xplornet.ca [Northern Nuclear Industries Incorporated, Cambridge, ON (Canada)

2015-07-01

Northern Nuclear Industries Incorporated (N{sup 2} I{sup 2}) is developing Small Modular Reactors (SMRs) called LEADIR-PS, an acronym for LEAD-cooled Integral Reactor-Passively Safe. LEADIR-PS integrates proven technologies including TRISO fuel, Pebble Bed core and graphite moderator, with molten lead coolant in an integral pool type reactor configuration to achieve unprecedented safety and economics. Plants under development are LEADIR-PS30, producing 30 MWth, LEADIR-PS100 producing 100 MWth and LEADIR-PS300 producing 300 MWth that are focused on serving the energy demands of areas with a small electrical grid and/or process heat applications. A plant consisting of six LEADIR-PS300 reactor modules serving a common turbine-generator, called the LEADIR-PS Six-Pack, is focused on serving areas with higher energy demands and a robust electricity grid. The Gen{sup +} I LEADIR-PS plants are inherently/passively safe. There is no potential for a Loss Of Coolant Accident, a reactivity transient without shutdown, a loss of heat sink, or hydrogen generation. No active systems or operator actions are required to assure safety. The unprecedented safety of LEADIR-PS reactors avoids large exclusion radius and demanding evacuation plan requirements. LEADIR-PS, with steam conditions of 370 {sup o}C and 12 MPa can serve over 85% of the world's non-transportation process heat demands. In Canada, the electricity and process heat demands, ranging from those of remote communities and the oil sands to densely populated areas can be served by LEADIR-PS. (author)

OCT/PS-OCT imaging of brachial plexus neurovascular structures

Science.gov (United States)

Raphael, David T.; Zhang, Jun; Zhang, Yaoping; Chen, Zhongping; Miller, Carol; Zhou, Li

2004-07-01

Introduction: Optical coherence tomography (OCT) allows high-resolution imaging (less than 10 microns) of tissue structures. A pilot study with OCT and polarization-sensitive OCT (PS-OCT) was undertaken to image ex-vivo neurovascular structures (vessels, nerves) of the canine brachial plexus. Methods: OCT is an interferometry-based optical analog of B-mode ultrasound, which can image through non-transparent biological tissues. With approval of the USC Animal Care and Use Committee, segments of the supra- and infraclavicular brachial plexus were excised from euthanized adult dogs, and the ex-vivo specimens were placed in cold pH-buffered physiologic solution. An OCT beam, in micrometer translational steps, scanned the fixed-position bisected specimens in transverse and longitudinal views. Two-dimensional images were obtained from identified arteries and nerves, with specific sections of interest stained with hematoxylin-eosin for later imaging through a surgical microscope. Results: with the beam scan direction transverse to arteries, the resulting OCT images showed an identifiable arterial lumen and arterial wall tissue layers. By comparison, transverse beam OCT images of nerves revealed a multitude of smaller nerve bundles contained within larger circular-shaped fascicles. PS-OCT imaging was helpful in showing the characteristic birefringence exhibited by arrayed neural structures. Discussion: High-resolution OCT imaging may be useful in the optical identification of neurovascular structures during attempted regional nerve blockade. If incorporated into a needle-shaped catheter endoscope, such a technology could prevent intraneural and intravascular injections immediately prior to local anesthetic injection. The major limitation of OCT is that it can form a coherent image of tissue structures only to a depth of 1.5 - 2 mm.

Picosecond time measurement using ultra fast analog memories

OpenAIRE

Breton, D.; Delagnes, E.; Maalmi, J.

2009-01-01

International audience; The currently existing electronics dedicated to precise time measurement is mainly based on the use of constant fraction discriminators (CFD) associated with Time to Digital Converters (TDC). The constant fraction technique minimizes the time walk effect (dependency of timing on the pulse amplitude). Several attempts have been made to integrate CFD in multi-channel ASICs. But the time resolution measured on the most advanced one is of the order of 30 ps rms. Two main t...

Energy- and time-resolved microscopy using PEEM: recent developments and state-of-the-art

Energy Technology Data Exchange (ETDEWEB)

Weber, N B; Escher, M; Merkel, M [FOCUS GmbH, Neukirchner Strasse 2, 65510 Huenstetten (Germany); Oelsner, A [Surface Concept GmbH, Staudingerweg 7, 55099 Mainz (Germany); Schoenhense, G [Johannes Gutenberg Universitaet, Institut fuer Physik, 55099 Mainz (Germany)], E-mail: n.weber@focus-gmbh.com

2008-03-15

Two novel methods of spectroscopic surface imaging are discussed, both based on photoemission electron microscopy PEEM. They are characterised by a simple electron-optical set up retaining a linear column. An imaging high-pass energy filter has been developed on the basis of lithographically-fabricated microgrids. Owing to a mesh size of only 7{mu}m, no image distortions occur. The present energy resolution is 70 meV. The second approach employs time-of-flight energy dispersion and time-resolved detection using a Delayline Detector. In this case, the drift energy and the time resolution of the detector determine the energy resolution. The present time resolution is 180 ps, giving rise to an energy resolution in the 100 meV range.

High-Rate Fast-Time GRPC for the high eta CMS muon detectors

CERN Document Server

Mirabito, Laurent

2016-01-01

CMS detector. In their single-gap version we will show that they can stand rates of few ${\\rm kHz/cm}^2$. We also demonstrate that using multi-gap glass RPC, a time resolution of about 60 ps is achieved.

Real-time database for high resolution neutron monitor measurements

Energy Technology Data Exchange (ETDEWEB)

Steigies, Christian T.; Rother, Oliver M.; Wimmer-Schweingruber, Robert F.; Heber, Bernd [IEAP, Christian-Albrechts-Universitaet zu Kiel (Germany)

2008-07-01

The worldwide network of standardised neutron monitors is, after 50 years, still the state-of-the-art instrumentation to measure spectral variations of the primary cosmic ray component. These measurements are an ideal complement to space based cosmic ray measurements. Data from the approximately 50 IGY and NM64 neutron monitors is stored locally but also available through data collections sites like the World Data Center (WDC) or the IZMIRAN ftp server. The data from the WDC is in a standard format, but only hourly values are available. IZMIRAN collects the data in the best available time resolution, but the data arrives on the ftp server only hours, sometimes days, after the measurements. Also, the high time-resolution measurements of the different stations do not have a common format, a conversion routine for each station is needed before they can be used for scientific analysis. Supported by the 7th framework program of the European Commission, we are setting up a real-time database where high resolution cosmic ray measurements will be stored and accessible immediately after the measurement. Stations that do not have 1-minute resolution measurements will be upgraded to 1-minute or better resolution with an affordable standard registration system, that will submit the measurements to the database via the internet in real-time.

Subpicosecond time-resolution image converter the picochron

International Nuclear Information System (INIS)

Butslov, M.M.; Fanchenko, S.D.; Chikin, R.V.

The problem of X-band resonance ultra-high-speed electron image swept in image converters is considered. A time analysis image converter tube is described. It is provided with a circular image-sweeping system, the sweeping speed ranging from 1 up to 2 light velocities. The swept-image intensifier makes it possible to record every electron emerging from the input photocathode. The time analysis electrostatic lens provides an electronic field at the input photocathode, strong enough to obtain a high physical time resolution. The image sweeping system to be described enables one to have a 5.10 -13 s time resolution over on observation period as long as 5.10 -8 s. It requires no precise limiting with the process to observed. The picochron tube design is described together with some results of its testing in Nd-laser experiments. Transitories as short as 0.5-1psec have been detected in ultra-short laser radiation pulses

Two-year survival rates of anti-TNF-α therapy in psoriatic arthritis (PsA) patients with either polyarticular or oligoarticular PsA.

Science.gov (United States)

Iannone, F; Lopriore, S; Bucci, R; Scioscia, C; Anelli, M G; Notarnicola, A; Lapadula, G

2015-05-01

To evaluate the 2-year drug survival rates of the tumour necrosis factor (TNF)-α blockers adalimumab, etanercept, and infliximab in psoriatic arthritis (PsA) patients with either oligoarticular (oligo-PsA) or polyarticular PsA (poly-PsA). We studied a prospective cohort of 328 PsA patients with peripheral arthritis (213 with poly-PsA and 115 with oligo-PsA), beginning their first ever anti-TNF-α treatment with adalimumab, etanercept, or infliximab. The aim of the study was to evaluate the drug survival rates and possible baseline predictors at 2 years. After 24 months, persistence in therapy with the first anti-TNF-α blocker was not statistically different in the oligo-PsA (70.4%) and poly-PsA (65.7%) subsets. Predictors of drug discontinuation were female sex [hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.00-2.68, p = 0.04] and starting the therapy in years 2003-8 (HR 0.51, 95% CI 0.33-0.80, p = 0.003). In poly-PsA, the persistence of etanercept (68.3%) was significantly higher than that of adalimumab (51.9%, p = 0.01), whereas in oligo-PsA no significant difference was detected. In poly-PsA, the period 2003-8 was a negative predictor (HR 0.36, 95% CI 0.21-0.62, p = 0.0001) whereas in oligo-PsA female gender was a positive predictor of drug discontinuation (HR 2.08, 95% CI 1.02-4.24, p = 0.04). With regard to clinical outcomes, the best responses in terms of European League Against Rheumatism (EULAR) 'good' response or Disease Activity Score (DAS28) remission, crude or adjusted according to the LUND Efficacy indeX (LUNDEX), were seen in patients on etanercept or infliximab. Our study provides some evidence that anti-TNF-α drugs may perform differently in PsA, and that the analysis of clinical disease subsets may improve our knowledge and promote better management of PsA.

Updating the Psoriatic Arthritis (PsA) Core Domain Set: A Report from the PsA Workshop at OMERACT 2016.

Science.gov (United States)

Orbai, Ana-Maria; de Wit, Maarten; Mease, Philip J; Callis Duffin, Kristina; Elmamoun, Musaab; Tillett, William; Campbell, Willemina; FitzGerald, Oliver; Gladman, Dafna D; Goel, Niti; Gossec, Laure; Hoejgaard, Pil; Leung, Ying Ying; Lindsay, Chris; Strand, Vibeke; van der Heijde, Désirée M; Shea, Bev; Christensen, Robin; Coates, Laura; Eder, Lihi; McHugh, Neil; Kalyoncu, Umut; Steinkoenig, Ingrid; Ogdie, Alexis

2017-10-01

To include the patient perspective in accordance with the Outcome Measures in Rheumatology (OMERACT) Filter 2.0 in the updated Psoriatic Arthritis (PsA) Core Domain Set for randomized controlled trials (RCT) and longitudinal observational studies (LOS). At OMERACT 2016, research conducted to update the PsA Core Domain Set was presented and discussed in breakout groups. The updated PsA Core Domain Set was voted on and endorsed by OMERACT participants. We conducted a systematic literature review of domains measured in PsA RCT and LOS, and identified 24 domains. We conducted 24 focus groups with 130 patients from 7 countries representing 5 continents to identify patient domains. We achieved consensus through 2 rounds of separate surveys with 50 patients and 75 physicians, and a nominal group technique meeting with 12 patients and 12 physicians. We conducted a workshop and breakout groups at OMERACT 2016 in which findings were presented and discussed. The updated PsA Core Domain Set endorsed with 90% agreement by OMERACT 2016 participants included musculoskeletal disease activity, skin disease activity, fatigue, pain, patient's global assessment, physical function, health-related quality of life, and systemic inflammation, which were recommended for all RCT and LOS. These were important, but not required in all RCT and LOS: economic cost, emotional well-being, participation, and structural damage. Independence, sleep, stiffness, and treatment burden were on the research agenda. The updated PsA Core Domain Set was endorsed at OMERACT 2016. Next steps for the PsA working group include evaluation of PsA outcome measures and development of a PsA Core Outcome Measurement Set.

A multi-channel time-to-digital converter chip for drift chamber readout

International Nuclear Information System (INIS)

Chau, A.; DeBusschere, D.; Dow, S.F.; Flasck, J.; Levi, M.E.; Kirsten, F.; Su, E.; Santos, D.M.

1996-01-01

A complete, multi-channel, timing and amplitude measurement IC for use in drift chamber applications is described. By targeting specific resolutions, i.e., 6-bits of resolution for both time and amplitude, area and power can be minimized while achieving the proper level of measurement accuracy. Time is digitized using an TDC comprised of a delay locked loop, latch and encoder. Amplitude (for dE/dx) is digitized using a dual-range FADC for each channel. Eight bits of dynamic range with six bits of accuracy are achieved with the dual-range. Eight complete channels of timing and amplitude information are multiplexed into one DRAM (Dynamic Random Access Memory) trigger latency buffer. Interesting events are subsequently transferred into an SRAM (Static Random Access Memory) readout buffer before the latency time has expired. The design has been optimized to achieve the requisite resolution using the smallest area and lowest power. The circuit has been implemented in an 0.8 microm triple metal CMOS process. The measured results indicate that the differential non-linearities of the TDC and the FADC are 200 ps and 10 mV, respectively. The integral nonlinearities of the TDC and the FADC are 230 ps and 9 mV, respectively

LS1 Report: PS Booster prepares for beam

CERN Multimedia

Katarina Anthony

2014-01-01

With Linac2 already up and running, the countdown to beam in the LHC has begun! The next in line is the PS Booster, which will close up shop to engineers early next week. The injector will be handed over to the Operations Group who are tasked with getting it ready for active duty.   Taken as we approach the end of LS1 activities, this image shows where protons will soon be injected from Linac2 into the four PS Booster rings. Over the coming two months, the Operations Group will be putting the Booster's new elements through their paces. "Because of the wide range of upgrades and repairs carried out in the Booster, we have a very full schedule of tests planned for the machine," says Bettina Mikulec, PS Booster Engineer in Charge. "We will begin with cold checks; these are a wide range of tests carried out without beam, including system tests with power on/off and with varying settings, as well as verification of the controls system and timings." Amon...

The PS locomotive runs again

CERN Multimedia

2001-01-01

Over forty years ago, the PS train entered service to steer the magnets of the accelerator into place... ... a service that was resumed last Tuesday. Left to right: Raymond Brown (CERN), Claude Tholomier (D.B.S.), Marcel Genolin (CERN), Gérard Saumade (D.B.S.), Ingo Ruehl (CERN), Olivier Carlier (D.B.S.), Patrick Poisot (D.B.S.), Christian Recour (D.B.S.). It is more than ten years since people at CERN heard the rumbling of the old PS train's steel wheels. Last Tuesday, the locomotive came back into service to be tested. It is nothing like the monstrous steel engines still running on conventional railways -just a small electric battery-driven vehicle employed on installing the magnets for the PS accelerator more than 40 years ago. To do so, it used the tracks that run round the accelerator. In fact, it is the grandfather of the LEP monorail. After PS was commissioned in 1959, the little train was used more and more rarely. This is because magnets never break down, or hardly ever! In fact, the loc...

An USB-based time measurement system

International Nuclear Information System (INIS)

Qin Xi; Liu Shubin; An Qi

2010-01-01

In this paper,we report the electronics of a timing measurement system of PTB(portable TDC board), which is a handy tool based on USB interface, customized for high precision time measurements without any crates. The time digitization is based on the High Performance TDC Chip (HPTDC). The real-time compensation for HPTDC outputs and the USB master logic are implemented in an ALTERA's Cyclone FPGA. The architecture design and logic design are described in detail. Test of the system showed a time resolution of 13.3 ps. (authors)

All-passive pixel super-resolution of time-stretch imaging

Science.gov (United States)

Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

2017-03-01

Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2-5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.

High resolution synchrotron light analysis at ELSA

Energy Technology Data Exchange (ETDEWEB)

Switka, Michael; Zander, Sven; Hillert, Wolfgang [Bonn Univ. (Germany). Elektronen-Stretcher Anlage ELSA-Facility (ELSA)

2013-07-01

The pulse stretcher ring ELSA provides polarized electrons with energies up to 3.5 GeV for external hadron experiments. In order to suffice the need of stored beam intensities towards 200 mA, advanced beam instability studies need to be carried out. An external diagnostic beamline for synchrotron light analysis has been set up and provides the space for multiple diagnostic tools including a streak camera with time resolution of <1 ps. Beam profile measurements are expected to identify instabilities and reveal their thresholds. The effect of adequate countermeasures is subject to analysis. The current status of the beamline development is presented.

Precision timing detectors with cadmium-telluride sensor

Science.gov (United States)

Bornheim, A.; Pena, C.; Spiropulu, M.; Xie, S.; Zhang, Z.

2017-09-01

Precision timing detectors for high energy physics experiments with temporal resolutions of a few 10 ps are of pivotal importance to master the challenges posed by the highest energy particle accelerators such as the LHC. Calorimetric timing measurements have been a focus of recent research, enabled by exploiting the temporal coherence of electromagnetic showers. Scintillating crystals with high light yield as well as silicon sensors are viable sensitive materials for sampling calorimeters. Silicon sensors have very high efficiency for charged particles. However, their sensitivity to photons, which comprise a large fraction of the electromagnetic shower, is limited. To enhance the efficiency of detecting photons, materials with higher atomic numbers than silicon are preferable. In this paper we present test beam measurements with a Cadmium-Telluride (CdTe) sensor as the active element of a secondary emission calorimeter with focus on the timing performance of the detector. A Schottky type CdTe sensor with an active area of 1cm2 and a thickness of 1 mm is used in an arrangement with tungsten and lead absorbers. Measurements are performed with electron beams in the energy range from 2 GeV to 200 GeV. A timing resolution of 20 ps is achieved under the best conditions.

Shallow PS-logging by high frequency wave; Koshuha wo mochiita senbu PS kenso

Energy Technology Data Exchange (ETDEWEB)

Nakajima, A; Miyazawa, M; Azuma, H [OYO Corp., Tokyo (Japan)

1996-05-01

This paper describes the following matters on down-hole PS logging in shallow subsurface. Determining an elastic wave velocity structure in shallow subsurface with high accuracy by using down-hole PS logging requires reduction of errors in reading travel time. Therefore, a high-frequency vibration source was fabricated with an objective to raise frequencies of waves used for the measurement. Measurements were made on two holes, A and B, at a measurement interval of 0.5 m, whereas at the hole A a measurement was performed simultaneously by using a normal type (low-frequency) vibration source. A spectral analysis on the waveform record revealed that the frequencies with each vibration source were 127 Hz and 27 Hz for the hole A, 115 Hz for the hole B, and the S/N ratio was all the same for both holes. When the high-frequency vibration source was used, the velocity was determined at accuracy of 5% over the whole length of the shallow section. When the low-frequency vibration source was used, sections with the velocity determining error greater than 5% were found, and it was not possible to derive the velocity structure in the shallow subsurface in fine segments. 3 refs., 8 figs., 2 tabs.

Towards time-of-flight PET with a semiconductor detector

Science.gov (United States)

Ariño-Estrada, Gerard; Mitchell, Gregory S.; Kwon, Sun Il; Du, Junwei; Kim, Hadong; Cirignano, Leonard J.; Shah, Kanai S.; Cherry, Simon R.

2018-02-01

The feasibility of using Cerenkov light, generated by energetic electrons following 511 keV photon interactions in the semiconductor TlBr, to obtain fast timing information for positron emission tomography (PET) was evaluated. Due to its high refractive index, TlBr is a relatively good Cerenkov radiator and with its wide bandgap, has good optical transparency across most of the visible spectrum. Coupling an SiPM photodetector to a slab of TlBr (TlBr-SiPM) yielded a coincidence timing resolution of 620 ps FWHM between the TlBr-SiPM detector and a LFS reference detector. This value improved to 430 ps FWHM by applying a high pulse amplitude cut based on the TlBr-SiPM and reference detector signal amplitudes. These results are the best ever achieved with a semiconductor PET detector and already approach the performance required for time-of-flight. As TlBr has higher stopping power and better energy resolution than the conventional scintillation detectors currently used in PET scanners, a hybrid TlBr-SiPM detector with fast timing capability becomes an interesting option for further development.

arXiv Performance of the ALICE Time-Of-Flight detector at the LHC

CERN Document Server

INSPIRE-00531272

The ALICE Time-Of-Flight (TOF) detector at LHC is based on the Multigap Resistive Plate Chambers (MRPCs). The TOF performance during LHC Run 2 is here reported. Particular attention is given to the improved time resolution reached by TOF detector of $56$ ps, with the consequently improved particle identification capabilities.

Time- and energy resolved photoemission electron microscopy-imaging of photoelectron time-of-flight analysis by means of pulsed excitations

International Nuclear Information System (INIS)

Oelsner, Andreas; Rohmer, Martin; Schneider, Christian; Bayer, Daniela; Schoenhense, Gerd; Aeschlimann, Martin

2010-01-01

The present work enlightens the developments in time- and energy resolved photoemission electron microscopy over the past few years. We describe basic principles of the technique and demonstrate different applications. An energy- and time-filtering photoemission electron microscopy (PEEM) for real-time spectroscopic imaging can be realized either by a retarding field or hemispherical energy analyzer or by using time-of-flight optics with a delay line detector. The latter method has the advantage of no data loss at all as all randomly incoming particles are measured not only by position but also by time. This is of particular interest for pump-probe experiments in the femtosecond and attosecond time scale where space charge processes drastically limit the maximum number of photoemitted electrons per laser pulse. This work focuses particularly on time-of-flight analysis using a novel delay line detector. Time and energy resolved PEEM instruments with delay line detectors enable 4D imaging (x, y, Δt, E Kin ) on a true counting basis. This allows a broad range of applications from real-time observation of dynamic phenomena at surfaces to fs time-of-flight spectro-microscopy and even aberration correction. By now, these time-of-flight analysis instruments achieve intrinsic time resolutions of 108 ps absolute and 13.5 ps relative. Very high permanent measurement speeds of more than 4 million events per second in random detection regimes have been realized using a standard USB2.0 interface. By means of this performance, the time-resolved PEEM technique enables to display evolutions of spatially resolved (<25 nm) and temporal sliced images life on any modern computer. The method allows dynamics investigations of variable electrical, magnetic, and optical near fields at surfaces and great prospects in dynamical adaptive photoelectron optics. For dynamical processes in the ps time scale such as magnetic domain wall movements, the time resolution of the delay line detectors

Gamma Transition Jump for PS2

CERN Document Server

Bartmann, W; Métral, E; Möhl, D; Peggs, S

2008-01-01

The PS2, which is proposed as a replacement for the existing ~50-year old PS accelerator, is presently considered to be a normal conducting synchrotron with an injection kinetic energy of 4 GeV and a maximum energy of 50 GeV. One of the possible lattices (FODO option) foresees crossing of transition energy near 10 GeV. Since the phase-slip-factor $\\eta$ becomes very small near transition energy, many intensity dependent effects can take place in both longitudinal and transverse planes. The aim of the present paper is on the one hand to scale the gamma transition jump, used since 1973 in the PS, to the projected PS2 and on the other hand based on these results the analysis of the implementation and feasibility of a gamma transition jump scheme in a conventional FODO lattice.

Time-interpolator

International Nuclear Information System (INIS)

Blok, M. de; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

1990-01-01

This report describes a time-interpolator with which time differences can be measured using digital and analog techniques. It concerns a maximum measuring time of 6.4 μs with a resolution of 100 ps. Use is made of Emitter Coupled Logic (ECL) and analogues of high-frequency techniques. The difficulty which accompanies the use of ECL-logic is keeping as short as possible the mutual connections and closing properly the outputs in order to avoid reflections. The digital part of the time-interpolator consists of a continuous running clock and logic which converts an input signal into a start- and stop signal. The analog part consists of a Time to Amplitude Converter (TAC) and an analog to digital converter. (author). 3 refs.; 30 figs

A time-of-flight system for precise measurements of a relativistic charged particle beam momentum

International Nuclear Information System (INIS)

Avramenko, S.A.; Belikov, Yu.A.; Golokhvastov, A.I.; Lukstin'sh, Yu.; Man'yakov, P.K.; Rukoyatkin, P.A.; Khorozov, S.A.

1996-01-01

A time-of-flight system with a time resolution (σ) about 100 ps is described. The methods for the calibration, stability verification and the method for the time resolution evaluation in conditions of a nonmonochromatic beam are discussed especially. The system was applied in charge exchange ( 3 H, 3 He) experiments with the GIBS spectrometer for a measurement of 3 H-nuclei momenta at 2 GeV/c per nucleon with a precision about 0.2%. (author). 4 refs., 7 figs., 1 tab

Effectiveness of early adalimumab therapy in psoriatic arthritis patients from Reuma.pt - EARLY PsA.

Science.gov (United States)

Santos, Helena; Eusébio, Mónica; Borges, Joana; Gonçalves, Diana; Ávila-Ribeiro, Pedro; Faria, Daniela Santos; Lopes, Carina; Rovisco, João; Águeda, Ana; Nero, Patrícia; Valente, Paula; Cravo, Ana Rita; Santos, Maria José

2017-01-01

Objective To compare outcomes in psoriatic arthritis (PsA) patients initiating adalimumab (ADA), with short- and long-term disease duration and to evaluate the potential effect of concomitant conventional synthetic disease-modifying antirheumatic drugs (csDMARD) or glucocorticoids. Methods Analyses included adult PsA patients registered in the Rheumatic Diseases Portuguese Register (Reuma.pt) between June 2008-June 2016 who received ADA for ≥3 months. Psoriatic Arthritis Response Criteria (PsARC) response, tender and swollen joint count, inflammatory parameters, patient (PtGA) and physician global assessment (PhGA), Disease Activity Score-28 joints (DAS28), and Health Assessment Questionnaire Disability Index (HAQ-DI) were compared between patients with PsA) and those with ≥5 years of disease duration (late PsA). Time to achieving PsARC response was estimated using the Kaplan-Meier method. Results Of 135 PsA patients treated with ADA, 126 had information on disease duration (earlyPsA, n=41). PsARC response was achieved by 72.9% of the patients (88.0% early PsA vs 62.2% late PsA; P=0.022) after 3 months and by 85.4% after 24 months (100% early PsA vs 75.9% late PsA; P=0.044). Early PsA patients achieved significantly less painful joints (2.7 vs 6.7, p=0.006), lower mean C-reactive protein (0.5 mg/dL vs 1.3 mg/dL; P=0.011), and PhGA (18.3 vs 28.1; P=0.020) at 3 months. In the long term, early PsA patients also had fewer swollen joints (0.3 vs 1.7; P=0.030) and lower PhGA (6.3 vs 21.9; PPsA, respectively. Early PsA patients obtained PsARC response more rapidly than late PsA (3.8 and 7.4 months, respectively; P=0.008). Concomitant csDMARDs showed clinical benefit (2-year PsARC response, 88.3% vs 60.0%; P=0.044). Concomitant glucocorticoids had no effect on PsARC response over 2 years of follow-up. Persistence on ADA was similar in both groups. Conclusion Early PsA patients had a greater chance of improvement after ADA therapy and better functional outcome, and

Plasma polarization spectroscopy. Time resolved spectroscopy in soft x-ray region on recombining plasma

International Nuclear Information System (INIS)

Iwamae, Atsushi; Hasuo, Masahiro; Atake, Makoto; Hasegawa, Noboru; Kawachi, Tetsuya

2007-01-01

We present an experimental study of polarization of emission radiations from recombining plasmas generated by the interaction of 60 fs ultra-short laser pulses with a gas jet. Time-resolved spectroscopy with a temporal resolution of 5 ps with repetitive accumulation is used to follow the recombination time histories. (author)

Prototype of time digitizing system for BESⅢ endcap TOF upgrade

International Nuclear Information System (INIS)

Cao Ping; Sun Weijia; Fan Huanhuan; Wang Siyu; Liu Shubin; An Qi; Ji Xiaolu

2014-01-01

The prototype of a time digitizing system for the BESⅢ endcap TOF (ETOF) upgrade is introduced in this paper. The ETOF readout electronics has a distributed architecture. Hit signals from the multi-gap resistive plate chamber (MRPC) are signaled as LVDS by front-end electronics (FEE) and are then sent to the back-end time digitizing system via long shield differential twisted pair cables. The ETOF digitizing system consists of two VME crates, each of which contains modules for time digitization, clock, trigger, fast control, etc. The time digitizing module (TDIG) of this prototype can support up to 72 electrical channels for hit information measurement. The fast control (FCTL) module can operate in barrel or endcap mode. The barrel FCTL fans out fast control signals from the trigger system to the endcap FCTLs, merges data from the endcaps and then transfers to the trigger system. Without modifying the barrel TOF (BTOF) structure, this time digitizing architecture benefits from improved ETOF performance without degrading the BTOF performance. Lab experiments show that the time resolution of this digitizing system can be lower than 20 ps, and the data throughput to the DAQ can be about 92 Mbps. Beam experiments show that the total time resolution can be lower than 45 ps. (authors)

A new delay line loops shrinking time-to-digital converter in low-cost FPGA

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jie, E-mail: zhangjie071063@163.com [State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, CAS, Wuhan, China, 430077 (China); University of Chinese Academy of Sciences, Beijing, China, 100049 (China); Zhou, Dongming [State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, CAS, Wuhan, China, 430077 (China)

2015-01-21

The article provides the design and test results of a new time-to-digital converter (TDC) based on delay line loops shrinking method and implemented in a low-cost field programmable gate array (FPGA) device. A technique that achieves high resolution with low cost and flexibility is presented. The technique is based on two delay line loops which are used to directly shrink the measured time interval in the designed TDC, and the resolution is dependent on the difference between the entire delay times of the two delay line loops. In order to realize high resolution and eliminate temperature influence, the two delay line loops consist of the same delay cells with the same number. A delay-locked loop (DLL) is used to stabilize the resolution against process variations and ambient conditions. Meanwhile, one method is used to accurately evaluate the resolution of the implemented TDC. The converter has been implemented in a general-propose FPGA device (Actel SmartFusion A2F200M3). A single shot resolution of the implemented converter is 63.3 ps and the measurement standard deviation is about 61.7 ps within the measurement range of 5 ns. - Highlights: • We provide a new FPGA-integrated time-to-digital converter based on delay line loops method which used two delay line loops to directly shrink time intervals with only rising edges. • The two delay line loops consist of the same delay cells with the same number and symmetrical structure. • The resolution is dependent on the difference between the entire delays of the two delay line loops. • We use delay-locked loop to stabilize the resolution against temperature and supply voltage.

A new delay line loops shrinking time-to-digital converter in low-cost FPGA

International Nuclear Information System (INIS)

Zhang, Jie; Zhou, Dongming

2015-01-01

The article provides the design and test results of a new time-to-digital converter (TDC) based on delay line loops shrinking method and implemented in a low-cost field programmable gate array (FPGA) device. A technique that achieves high resolution with low cost and flexibility is presented. The technique is based on two delay line loops which are used to directly shrink the measured time interval in the designed TDC, and the resolution is dependent on the difference between the entire delay times of the two delay line loops. In order to realize high resolution and eliminate temperature influence, the two delay line loops consist of the same delay cells with the same number. A delay-locked loop (DLL) is used to stabilize the resolution against process variations and ambient conditions. Meanwhile, one method is used to accurately evaluate the resolution of the implemented TDC. The converter has been implemented in a general-propose FPGA device (Actel SmartFusion A2F200M3). A single shot resolution of the implemented converter is 63.3 ps and the measurement standard deviation is about 61.7 ps within the measurement range of 5 ns. - Highlights: • We provide a new FPGA-integrated time-to-digital converter based on delay line loops method which used two delay line loops to directly shrink time intervals with only rising edges. • The two delay line loops consist of the same delay cells with the same number and symmetrical structure. • The resolution is dependent on the difference between the entire delays of the two delay line loops. • We use delay-locked loop to stabilize the resolution against temperature and supply voltage

A High Resolution Spallation Driven Facility at the CERN-PS to Measure Neutron Cross Sections in the Interval from 1 eV to 250 MeV a Relative Performance Assessment

CERN Document Server

Rubbia, Carlo; Bouvet-Bensimon, D; Buono, S; Cappi, R; Cennini, P; Gelès, C; Goulas, I; Kadi, Y; Pavlopoulos, P; Revol, Jean Pierre Charles; Tzima, A; Vlachoudis, V

1998-01-01

In the proposed facility with 24 GeV PS beam on a Lead target, the number of produced neutrons exceeds 760 per proton. In comparison, with a LINAC (GELINA) one currently obtains only about 0.05 neutrons per electron of about 100 MeV. An additional factor of 2.5 for the CERN facility is due to the strong, forward peaking of the neutron flux, arising from the high proton energy and corresponding longitudinal boost. This huge factor in neutron yield per incident particle, namely 2.5 x 760/0.05 = 3.8 x 10^4, is only partially off-set by the higher, time averaged current of the LINAC e.g. 100 mA vs . 2 mA of the CERN-PS. Therefore the useful, initial neutron rate at the CERN facility is about three orders of magnitude larger than in the most performing electron LINAC’s, GELINA in Belgium and ORELLA in the US. The time duration of the PS pulse is presently Deltat|_r.m.s.=13.5 ns and we believe it could be reduced to Deltat|_r.m.s.= 6.75 ns. The electron LINAC has much shorter pulses Deltat| _r.m.s.= 1 ns, to which...

Novel techniques in VUV high-resolution spectroscopy

NARCIS (Netherlands)

Ubachs, W.M.G.; Salumbides, E.J.; Eikema, K.S.E.; de Oliveira, N.; Nahon, L.

2014-01-01

Novel VUV sources and techniques for VUV spectroscopy are reviewed. Laser-based VUV sources have been developed via non-linear upconversion of laser pulses in the nanosecond (ns), the picosecond (ps), and femtosecond (fs) domain, and are applied in high-resolution gas phase spectroscopic studies.

Correction of time resolution of an ambulatory cardiac monitor (VEST)

International Nuclear Information System (INIS)

Kumita, Shin-ichiro; Nishimura, Tsunehiko; Hayashida, Kohei; Uehara, Toshiisa

1990-01-01

Using ambulatory cardiac monitor (VEST) at exercise study, its time resolution is very important factor. We evaluated the time resolution of VEST using pulsate cardiac baloon phantom. Four analysis were carried out; no smoothing (NS) method, 3 points smoothing (3S) method, short sampling interval (SS) method, and digital filter (DF) method. By comparison of |ΔEF| (|EF:HR120-EF: HR60|) among 4 analysis methods, |ΔEF| by DF method was significant small (NS:3.58±3.01, 3S: 4.46±0.95, SS: 3.35±3.26, DF: 1.11±1.28%). We conclude that correction of time resolution by digital filter is necessary when we use VEST during exercise. (author)

Improvement of Data Acquisition of the BRTR (PS-43) Seismic Array

Science.gov (United States)

Ozel, N. M.; Kocak, S.; Semin, K. U.; Necmioglu, O.; Destici, T. C.; Teoman, U.

2010-05-01

Bogazici University, Kandilli Observatory and Earthquake Research Institute(KOERI) is currently operating the BRTR( PS-43) seismic arrays located in the vicinity of Ankara and town Keskin, providing real-time data to IDC. PS-43 is composed of two sub-arrays, the medium-period array with a ~45km radius located in Ankara and the short-period array with ~3 km radius located in Keskin. In 2009, data availabilty of the BRTR is exceeded %98 that value is the requirment of IDC. Substantial contribution to obtain this availabiliy is implementing the improvements that mainly replacement of the grid type parabolic antennas with the heavy-duty dish antennas at necessary sites called the repeater sites RE-BRTR (CCF), RE-PS43 (Mt. Elmadag), CF-PS43 (Central Recording Building) and all MP sites. Even this renewed system is at the tentative stage, communication status of the seismic arrays are solid and continuous. BRTR is expecting another improvement, June 2010, about the power system at Mt. Elmadag and the MP site BR237. Completion of this improvement will be stabilize of our current mission.

The ARGUS time-of-flight system

International Nuclear Information System (INIS)

Heller, R.; Klinger, T.; Salomon, R.; Schubert, K.R.; Stiewe, J.; Waldi, R.; Weseler, S.

1985-01-01

The time-of-flight system of the ARGUS detector at the DORIS e + e - storage ring consists of 64 barrel scintillation counters covering 75% of 4π, and 2x48 end cap counters, covering 17% of 4π. The barrel counters are viewed by two phototubes each, while the end cap counters have one tube only. The time-of-flight system serves as a part of the fast trigger and identifies charged particles. The time resolution achieved during the first year of ARGUS operation is 210 ps for Bhabhas (which are used for the off-line monitoring of the system), and 220 ps for hadrons, both in barrel and end cap counters. This converts into a three standard deviation mass separation up to 700 MeV/c between pions and kaons and 1200 MeV/c between kaons and protons. Electrons can be separated from heavier particles up to 230 MeV/c. (orig.)

Functional characterization of calcineurin homologs PsCNA1/PsCNB1 in Puccinia striiformis f. sp. tritici using a host-induced RNAi system.

Directory of Open Access Journals (Sweden)

Hong Zhang

Full Text Available Calcineurin plays a key role in morphogenesis, pathogenesis and drug resistance in most fungi. However, the function of calcineurin genes in Puccinia striiformis f. sp. tritici (Pst is unclear. We identified and characterized the calcineurin genes PsCNA1 and PsCNB1 in Pst. Phylogenetic analyses indicate that PsCNA1 and PsCNB1 form a calcium/calmodulin regulated protein phosphatase belonging to the calcineurin heterodimers composed of subunits A and B. Quantitative RT-PCR analyses revealed that both PsCNA1 and PsCNB1 expression reached their maximum in the stage of haustorium formation, which is one day after inoculation. Using barely stripe mosaic virus (BSMV as a transient expression vector in wheat, the expression of PsCNA1 and PsCNB1 in Pst was suppressed, leading to slower extension of fungal hyphae and reduced production of urediospores. The immune-suppressive drugs cyclosporin A and FK506 markedly reduced the germination rates of urediospores, and when germination did occur, more than two germtubes were produced. These results suggest that the calcineurin signaling pathway participates in stripe rust morphogenetic differentiation, especially the formation of haustoria during the early stage of infection and during the production of urediospores. Therefore PsCNA1 and PsCNB1 can be considered important pathogenicity genes involved in the wheat-Pst interaction.

Experiments at the KEK 12-GeV PS in 1991-1995

International Nuclear Information System (INIS)

Yoshimura, Y.

1994-06-01

This report has been edited mainly to introduce the various activities at the KEK 12-GeV PS. Chapter 1 is a list of experiments which have been approved by the PS-PAC since May 2, 1975. The machine time executed from FY 1990 to Fy 1993 is shown in chapter 2. In chapter 4, experiments which are currently in various stages of preparation, running and data analyzing are briefly described. The information was extracted from the 'KEK-PS Proposal', 'KEK Annual Report 1990-1993' and various published papers listed in chapter 5. In the descriptions the author sometimes might give 'sensitive' information concerning the experimental groups very directly. Readers of this publication are therefore requested not to directly quote the descriptions given in chapter 4. (J.P.N.)

Analytical model of SiPM time resolution and order statistics with crosstalk

International Nuclear Information System (INIS)

Vinogradov, S.

2015-01-01

Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented

Analytical model of SiPM time resolution and order statistics with crosstalk

Energy Technology Data Exchange (ETDEWEB)

Vinogradov, S., E-mail: Sergey.Vinogradov@liverpool.ac.uk [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD (United Kingdom); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, 119991 Leninskiy Prospekt 53, Moscow (Russian Federation)

2015-07-01

Time resolution is the most important parameter of photon detectors in a wide range of time-of-flight and time correlation applications within the areas of high energy physics, medical imaging, and others. Silicon photomultipliers (SiPM) have been initially recognized as perfect photon-number-resolving detectors; now they also provide outstanding results in the scintillator timing resolution. However, crosstalk and afterpulsing introduce false secondary non-Poissonian events, and SiPM time resolution models are experiencing significant difficulties with that. This study presents an attempt to develop an analytical model of the timing resolution of an SiPM taking into account statistics of secondary events resulting from a crosstalk. Two approaches have been utilized to derive an analytical expression for time resolution: the first one based on statistics of independent identically distributed detection event times and the second one based on order statistics of these times. The first approach is found to be more straightforward and “analytical-friendly” to model analog SiPMs. Comparisons of coincidence resolving times predicted by the model with the known experimental results from a LYSO:Ce scintillator and a Hamamatsu MPPC are presented.

Compact time-zero detector for heavy ions

International Nuclear Information System (INIS)

Weissenberger, E.; Kast, W.; Goennenwein, F.

1979-01-01

A time-zero detector for flight-time measurements with heavy ions is described. The ions traverse a thin foil and the secondary electrons splashed from the foil are detected in a channel plate multiplier. A timing signal is derived from the multiplier pulse. The novel features of the detector are its simplicity and compactness of design. The time resolution achieved for the full energy and mass span of fission fragments from the spontaneous fission of 252 Cf used as a heavy ion source is 115 ps (fwhm). (Auth.)

PsHint1, associated with the G-protein α subunit PsGPA1, is required for the chemotaxis and pathogenicity of Phytophthora sojae.

Science.gov (United States)

Zhang, Xin; Zhai, Chunhua; Hua, Chenlei; Qiu, Min; Hao, Yujuan; Nie, Pingping; Ye, Wenwu; Wang, Yuanchao

2016-02-01

Zoospore chemotaxis to soybean isoflavones is essential in the early stages of infection by the oomycete pathogen Phytophthora sojae. Previously, we have identified a G-protein α subunit encoded by PsGPA1 which regulates the chemotaxis and pathogenicity of P. sojae. In the present study, we used affinity purification to identify PsGPA1-interacting proteins, including PsHint1, a histidine triad (HIT) domain-containing protein orthologous to human HIT nucleotide-binding protein 1 (HINT1). PsHint1 interacted with both the guanosine triphosphate (GTP)- and guanosine diphosphate (GDP)-bound forms of PsGPA1. An analysis of the gene-silenced transformants revealed that PsHint1 was involved in the chemotropic response of zoospores to the isoflavone daidzein. During interaction with a susceptible soybean cultivar, PsHint1-silenced transformants displayed significantly reduced infectious hyphal extension and caused a strong cell death in plants. In addition, the transformants displayed defective cyst germination, forming abnormal germ tubes that were highly branched and exhibited apical swelling. These results suggest that PsHint1 not only regulates chemotaxis by interacting with PsGPA1, but also participates in a Gα-independent pathway involved in the pathogenicity of P. sojae. © 2015 BSPP AND JOHN WILEY & SONS LTD.

Time-resolved optical spectrometer based on a monolithic array of high-precision TDCs and SPADs

Science.gov (United States)

Tamborini, Davide; Markovic, Bojan; Di Sieno, Laura; Contini, Davide; Bassi, Andrea; Tisa, Simone; Tosi, Alberto; Zappa, Franco

2013-12-01

We present a compact time-resolved spectrometer suitable for optical spectroscopy from 400 nm to 1 μm wavelengths. The detector consists of a monolithic array of 16 high-precision Time-to-Digital Converters (TDC) and Single-Photon Avalanche Diodes (SPAD). The instrument has 10 ps resolution and reaches 70 ps (FWHM) timing precision over a 160 ns full-scale range with a Differential Non-Linearity (DNL) better than 1.5 % LSB. The core of the spectrometer is the application-specific integrated chip composed of 16 pixels with 250 μm pitch, containing a 20 μm diameter SPAD and an independent TDC each, fabricated in a 0.35 μm CMOS technology. In front of this array a monochromator is used to focus different wavelengths into different pixels. The spectrometer has been used for fluorescence lifetime spectroscopy: 5 nm spectral resolution over an 80 nm bandwidth is achieved. Lifetime spectroscopy of Nile blue is demonstrated.

Femtosecond Resolution Timing in Multi-GS/s Waveform Digitizing ASICs

Science.gov (United States)

Orel, Peter; Varner, Gary S.

2017-07-01

A waveform digitizer with high-resolution timing provides with the possibility of a novel approach to vertex detectors for high-luminosity particle colliders. Present efforts are centered on the development of an application specific integrated circuit (ASIC) intended to measure signal arrival times with timing resolution in the range of 100 fs or less. The design of such an ASIC requires very good understanding of the effects that impact the timing resolution. This paper presents the simulation results that clearly identify and quantify the sources of error and the underlying coupling mechanisms. In addition, a synthetic waveform generator, developed solely for this purpose, is presented and validated through the measurement results. Crucial knowledge, insights, and confidence have been gained for the development of the ASIC or any other fast, wideband RF systems that aim to achieve such performance.

Motor-Generator Set, PS Main Supply

CERN Multimedia

CERN PhotoLab

1983-01-01

This is the "new" motor-generator set. It replaced the previous, original, one which had served from the PS start-up in 1959. Ordered in 1965, installed in 1967, it was brought into operation at the beginning of 1968. Regularly serviced and fitted with modern regulation and controls, it still serves at the time of writing (2006) and promises to serve for several more years, as a very much alive museum-piece. See also 6803016 and 0201010.

Measuring target for the PS Booster

CERN Multimedia

1971-01-01

The measuring target for the PS Booster (originally 800 MeV, now 1.4 GeV). It measures the size of the beam by destroying all particles with amplitudes greater than the size of the fork, the position and width of which are adjustable. The plunging time is only 20 ms and the acceleration at the tip of the fork reaches 90 g. The servo-controlled linear motor is shown detached from the mechanism. See also 7602008.

Microfabrication of biomaterials by the sub-ps laser-induced forward transfer process

International Nuclear Information System (INIS)

Karaiskou, A.; Zergioti, I.; Fotakis, C.; Kapsetaki, M.; Kafetzopoulos, D.

2003-01-01

The precise fabrication of micro-dimensioned patterns of biomaterials by the laser microprinting technique using a sub-ps UV laser is described. An ultrashort UV laser has been used to transfer the biomaterial, with low angular divergence, and deposit it onto the substrate with minimum spread and high spatial resolution. The laser-transferred features of 100 μmx100 μm size have been studied by means of scanning electron microscopy and scanning laser confocal fluorescence microscopy. The analysis of DNA and protein microarrays provides an excellent tool to expand our knowledge of genome functions

Timing performance of ZnO:Ga nanopowder composite scintillators

Energy Technology Data Exchange (ETDEWEB)

Turtos, Rosana M. [Universita degli Studi di Milano-Bicocca, Milano (Italy); Gundacker, Stefan; Lucchini, Marco T.; Lecoq, Paul; Auffray, Etiennette [CERN, Geneva (Switzerland); Prochazkova, Lenka; Cuba, Vaclav [Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Prague (Czech Republic); Buresova, Hana [Nuvia a.s, Kralupy nad Vltavou (Czech Republic); Mrazek, Jan [Institute of Photonics and Electronics AS CR, Prague (Czech Republic); Nikl, Martin [Institute of Physics of the AS CR, Prague (Czech Republic)

2016-11-15

The implementation of nanocrystal-based composite scintillators as a new generation of ultrafast particle detectors is explored using ZnO:Ga nanopowder. Samples are characterized with a spectral-time resolved photon counting system and pulsed X-rays, followed by coincidence time resolution (CTR) measurements under 511 keV gamma excitation. Results are comparable to CTR values obtained using bulk inorganic scintillators. Bringing the ZnO:Ga nanocrystal's timing performance to radiation detectors could pave the research path towards sub-20 ps time resolution as shown in this contribution. However, an efficiency boost when placing nanopowders in a transparent host constitutes the main challenge in order to benefit from sub-nanosecond recombination times. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Comparison of charge collection in semiconductor detectors and timing resolution, using a sub-nanosecond transimpedance amplifier

International Nuclear Information System (INIS)

Rudge, A.

1995-01-01

A transimpedance amplifier, with a risetime of <600 ps and a noise of <1000 RMS electrons in a 500 MHz bandwidth, has been used for comparison of charge collection times in silicon, gallium arsenide and diamond detectors. The use of silicon detectors as trigger counters/hodoscopes is demonstrated, together with measured timing characteristics. (orig.)

Comparison of charge collection in semiconductor detectors and timing resolution, using a sub-nanosecond transimpedance amplifier

Energy Technology Data Exchange (ETDEWEB)

Rudge, A. [European Organization for Nuclear Research, Geneva (Switzerland)

1995-06-01

A transimpedance amplifier, with a risetime of <600 ps and a noise of <1000 RMS electrons in a 500 MHz bandwidth, has been used for comparison of charge collection times in silicon, gallium arsenide and diamond detectors. The use of silicon detectors as trigger counters/hodoscopes is demonstrated, together with measured timing characteristics. (orig.).

Enhanced personal protection at the PS

CERN Multimedia

Samuel Morier Genoud

2013-01-01

Pictures 03, 06, 07 08 : Pierre Ninin, deputy group leader of GS-ASE and responsible for the installation of the new PS complex safety system, in front of a new access control system.Pictures 10, 12 ,13 : View of Building 271, the future control centre of the new PS complex safety system.

Using PS-InSAR data in landslide hazard management: the case of Veneto Region (NE Italy)

Science.gov (United States)

Floris, Mario; Viganò, Alessandro; Busnardo, Enrico; Arziliero, Luciano; Zanette, Doriano

2013-04-01

scale (single Municipality) we propose to analyze more in depth displacements time series to better evaluate the occurrence of landslides characterized by high frequency of reactivation and to identify the relationships with rainfall considered as triggering factor. Results from our study will help in identifying the actual possibility to use PS-InSAR data in landslide characterization and monitoring. Starting from these results an update of current landslide inventories and a planning to monitor the evolution of instabilities is possible. To these purposes, in the next future we are going to process high resolution SAR data acquired by Cosmo SKY Med satellites characterized also by a high revisit period, and to implement new systems for a near real time monitoring.

High Time Resolution Astrophysics

CERN Document Server

Phelan, Don; Shearer, Andrew

2008-01-01

High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

The PS will soon be back in operation

CERN Multimedia

2006-01-01

The PS's power supply system is undergoing repairs for the accelerator to restart on 26 June. The AB Department's Power Converter Group is working flat out with Siemens to return the PS's power supply system to working order. A problem appeared on the insulation of the power cables of the rotor of the rotating machine (photo) which supplies power to the PS magnets. To prevent more significant damage to the rotating machine, the AB Department, with the approval of the CERN Management, decided to shut down the PS which had started running on 15 May. Everything is being done to restart the accelerator on 26 June. The PS's rotating machine comprises a motor coupled to a generator. The generator's rotor acts like a flywheel, supplying high-power pulses of 40 to 50 megawatts to the PS magnets. The 6 megawatt motor drives the installation at 1000 revolutions per minute and compensates only for variations in speed. It is an essential interface since it would be hard to imagine connecting such an electrical charge, p...

The development of the Asian Forum for Polar Sciences (AFoPS)

Science.gov (United States)

Kim, Yeadong; Jeong, Jihoon

2015-12-01

The Asian Forum for Polar Sciences (AFoPS), an international forum of Asian polar research institutes, was established for the advancement of polar sciences among its members in 2004. The Forum has served as an important medium of Asian collective endeavors for polar affairs in human and information exchange, research collaboration, and logistics cooperation for the last decade. The historical development of the AFoPS in retrospect can be divided into four phases: inception and establishment (2003-2004), growth and expansion (2005-2007), review and restructuring (2008-2011), and achievements and further measures (2012-2014). The progress of the AFoPS has not been linear and this trend will continue into the next decades. The Forum, however, clearly made achievements in this period of time, realizing multilateral research and logistics cooperation that would have been previously unimaginable; by doing so, it has laid the foundation for the future. Responsible for a great portion of the world's polar activities, the AFoPS will rise to meet the expectations of the world by producing notable research output, initiating international cooperative programs, and supporting non-polar Asian countries with education and research collaboration. These are the tasks of the AFoPS for the next decade and they require strategy that promotes and facilitates collaboration in a practical way and draws attention of non-polar Asian countries to the polar sciences.

Quantitative analysis of intraneuronal transport in human iPS neurons

Directory of Open Access Journals (Sweden)

Haruko Nakamura

2015-08-01

Full Text Available Induced pluripotent stem (iPS cells are promising tools to investigate disease mechanism and develop new drugs. Intraneuronal transport, which is fundamental for neuronal survival and function, is vulnerable to various pharmacological and chemical agents and is disrupted in some neurodegenerative disorders. We applied a quantification method for axonal transport by counting CM-DiI–labeled particles traveling along the neurite, which allowed us to monitor and quantitate, for the first time, intraneuronal transport in human neurons differentiated from iPS cells (iCell neurons. We evaluated the acute effects of several anti-neoplastic agents that have been previously shown to affect intraneuronal transport. Vincristine, paclitaxel and oxaliplatin decreased the number of moving particle along neurites. Cisplatin, however, produced no effect on intraneuronal transport, which is in contrast to our previous report indicating that it inhibits transport in chick dorsal root ganglion neurons. Our system may be a useful method for assessing intraneuronal transport and neurotoxicity in human iPS neurons.

Multi-Channel Amplifier-Discriminator for Highly Time-Resolved Detection

CERN Document Server

Despeisse, M; Lapington, J; Jarron, P

2011-01-01

A low-power multi-channel amplifier-discriminator was developed for application in highly time-resolved detection systems. The proposed circuit architecture, so-called Nino, is based on a time-over-threshold approach and shows a high potential for time-resolved readout of solid-state photo-detectors and of detectors based on vacuum technologies. The Irpics circuit was designed in a 250 nm CMOS technology, implementing 32 channels of a Nino version optimized to achieve high-time resolution on the output low-voltage differential signals (LVDS) while keeping a low power consumption of 10 mW per channel. Electrical characterizations of the circuit demonstrate a very low intrinsic time jitter on the output pulse leading edge, measured below 10 ps rms for each channel for high input signal charges (100 fC) and below 25 ps rms for low input signal charges (20-100 fC). The read-out architecture moreover permits to retrieve the input signal charge from the timing measurements, while a calibration procedure was develop...

Proper-time resolution function for measurement of time evolution of B mesons at the KEK B-Factory

International Nuclear Information System (INIS)

Tajima, H.; Aihara, H.; Higuchi, T.; Kawai, H.; Nakadaira, T.; Tanaka, J.; Tomura, T.; Yokoyama, M.; Hazumi, M.; Sakai, Y.; Sumisawa, K.; Kawasaki, T.

2004-01-01

The proper-time resolution function for the measurement of the time evolution of B mesons with the Belle detector at KEKB is studied in detail. The obtained resolution function is applied to the measurement of B meson lifetimes, the B0B-bar 0 oscillation frequency and time-dependent CP asymmetries

Synthesis and Characterization of the Rubidium Thiophosphate Rb 6 (PS 5 )(P 2 S 10 ) and the Rubidium Silver Thiophosphates Rb 2 AgPS 4 , RbAg 5 (PS 4 ) 2 and Rb 3 Ag 9 (PS 4 ) 4

KAUST Repository

Alahmary, Fatimah S.

2016-02-18

The metal thiophosphates Rb2AgPS4 (2), RbAg5(PS4)2 (3), and Rb3Ag9(PS4)4 (4) were synthesized by stoichiometric reactions, whereas Rb6(PS5)(P2S10) (1) was prepared with excess amount of sulfur. The compounds crystallize as follows: 1 monoclinic, P21/c (no. 14), a = 17.0123(7) Å, b = 6.9102(2) Å, c = 23.179(1) Å, β = 94.399(4)°; 2 triclinic, P ¯ (no. 2), a = 6.600(1) Å, b = 6.856(1) Å, c = 10.943(3) Å, α = 95.150(2)°, β = 107.338(2)°, γ = 111.383(2)°; 3 orthorhombic, Pbca (no. 61), a = 12.607(1) Å, b = 12.612(1) Å, c = 17.759(2) Å; 4 orthorhombic, Pbcm (no. 57), a = 6.3481(2) Å, b = 12.5782(4) Å, c = 35.975(1) Å. The crystal structures contain discrete units, chains, and 3D polyanionic frameworks composed of PS4 tetrahedral units arranged and connected in different manner. Compounds 1-3 melt congruently, whereas incongruent melting behavior was observed for compound 4. 1-4 are semiconductors with bandgaps between 2.3 and 2.6 eV and thermally stable up to 450 °C in an inert atmosphere. Copyright © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-precision calculation of loosely bound states of LiPs+ and NaPs+

International Nuclear Information System (INIS)

Yamashita, Takuma; Kino, Yasushi

2015-01-01

A positronic alkali atom would be the first step to investigate behavior of a positronium(Ps) in an external field from atoms/molecules because the system can be regarded as a simple three-body system using model potentials reflecting electron orbitals of the ion core. In order to precisely determine binding energies and structures of positronic alkali atoms (LiPs + and NaPs + ), we improve the model potential so as to reproduce highly excited atomic energy levels of alkali atoms (Li and Na). The polarization potential included by the model potential is expanded in terms of Gaussian functions to finely determine a short range part of the potential which has been assumed to be a simple form. We find better reproducibility not only of atomic levels of the alkali atoms but also of the dipole polarizability of the core ion than previous works. We construct a model potential between a positron and an ion core based on the model potential between the valence electron and ion core. Binding energies associated with a dissociation of the alkali ion core and positronium, and interparticle distances are recalculated. Our results show slightly deeper bound than other previous studies. (paper)

Spectroscopic investigations of hard x-ray emission from 120 ps laser-produced plasmas at intensities near 1017 W cm-2

International Nuclear Information System (INIS)

Dunn, J.; Young, B.K.F.; Osterheld, A.L.; Foord, M.E.; Walling, R.S.; Stewart, R.E.; Faenov, A.Y.

1995-11-01

Spectroscopic investigations of the x-ray emission of plasmas heated by 120 ps, frequency doubled pulses from the JANUS Nd: glass laser are presented. High Z K-shell spectra emitted from slab targets heated to near 10 17 W cm -2 intensity are investigated. High resolution (γ/Δγ>5000) x-ray spectra of multicharged ions of H-like Ti, Co, Ni, Cu, and also H-like Sc in the spectral range 1.5--3.0 angstrom are obtained in single laser shots using a spherically bent Mica crystal spectrograph with a 186 mm radius of curvature. The spectra- have one dimensional spatial resolution of about 25μm and indicate that the size of the emission zone of the resonance, transitions is 2 keV and density∼10 22 cm -3 . These experiments demonstrate that with modest laser energy, plasmas heated by high-intensity 120 ps lasers provide a very bright source of hard ∼8 keV x-ray emission

Using convolutional neural networks to estimate time-of-flight from PET detector waveforms

Science.gov (United States)

Berg, Eric; Cherry, Simon R.

2018-01-01

Although there have been impressive strides in detector development for time-of-flight positron emission tomography, most detectors still make use of simple signal processing methods to extract the time-of-flight information from the detector signals. In most cases, the timing pick-off for each waveform is computed using leading edge discrimination or constant fraction discrimination, as these were historically easily implemented with analog pulse processing electronics. However, now with the availability of fast waveform digitizers, there is opportunity to make use of more of the timing information contained in the coincident detector waveforms with advanced signal processing techniques. Here we describe the application of deep convolutional neural networks (CNNs), a type of machine learning, to estimate time-of-flight directly from the pair of digitized detector waveforms for a coincident event. One of the key features of this approach is the simplicity in obtaining ground-truth-labeled data needed to train the CNN: the true time-of-flight is determined from the difference in path length between the positron emission and each of the coincident detectors, which can be easily controlled experimentally. The experimental setup used here made use of two photomultiplier tube-based scintillation detectors, and a point source, stepped in 5 mm increments over a 15 cm range between the two detectors. The detector waveforms were digitized at 10 GS s-1 using a bench-top oscilloscope. The results shown here demonstrate that CNN-based time-of-flight estimation improves timing resolution by 20% compared to leading edge discrimination (231 ps versus 185 ps), and 23% compared to constant fraction discrimination (242 ps versus 185 ps). By comparing several different CNN architectures, we also showed that CNN depth (number of convolutional and fully connected layers) had the largest impact on timing resolution, while the exact network parameters, such as convolutional

Time walk correction for TOF-PET detectors based on a monolithic scintillation crystal coupled to a photosensor array

International Nuclear Information System (INIS)

Vinke, R.; Loehner, H.; Schaart, D.R.; Dam, H.T. van; Seifert, S.; Beekman, F.J.; Dendooven, P.

2010-01-01

When optimizing the timing performance of a time-of-flight positron emission tomography (TOF-PET) detector based on a monolithic scintillation crystal coupled to a photosensor array, time walk as a function of annihilation photon interaction location inside the crystal needs to be considered. In order to determine the 3D spatial coordinates of the annihilation photon interaction location, a maximum likelihood estimation algorithm was developed, based on a detector characterization by a scan of a 511 keV photon beam across the front and one of the side surfaces of the crystal. The time walk effect was investigated using a 20 mmx20 mmx12 mm LYSO crystal coupled to a fast 4x4 multi-anode photomultiplier tube (MAPMT). In the plane parallel to the photosensor array, a spatial resolution of 2.4 mm FWHM is obtained. In the direction perpendicular to the MAPMT (depth-of-interaction, DOI), the resolution ranges from 2.3 mm FWHM near the MAPMT to 4 mm FWHM at a distance of 10 mm. These resolutions are uncorrected for the ∼1mm beam diameter. A coincidence timing resolution of 358 ps FWHM is obtained in coincidence with a BaF 2 detector. A time walk depending on the 3D annihilation photon interaction location is observed. Throughout the crystal, the time walk spans a range of 100 ps. Calibration of the time walk vs. interaction location allows an event-by-event correction of the time walk.

Time and position resolution of high granularity, high counting rate MRPC for the inner zone of the CBM-TOF wall

CERN Document Server

Petriş, M.

2016-09-13

Multi-gap RPC prototypes with readout on a multi-strip electrode were developed for the small polar angle region of the CBM-TOF subdetector, the most demanding zone in terms of granularity and counting rate. The prototypes are based on low resistivity ($\\sim$10$^{10}$ $\\Omega$cm) glass electrodes for performing in high counting rate environment. The strip width/pitch size was chosen such to fulfill the impedance matching with the front-end electronics and the granularity requirements of the innermost zone of the CBM-TOF wall. The in-beam tests using secondary particles produced in heavy ion collisions on a Pb target at SIS18 - GSI Darmstadt and SPS - CERN were focused on the performance of the prototype in conditions similar to the ones expected at SIS100/FAIR. An efficiency larger than 98\\% and a system time resolution in the order of 70~-~80~ps were obtained in high counting rate and high multiplicity environment.

Comparative, validity and responsiveness of the HOOS-PS and KOOS-PS to the WOMAC physical function subscale in total joint replacement for osteoarthritis

DEFF Research Database (Denmark)

Davis, A M; Perruccio, A V; Canizares, M

2009-01-01

OBJECTIVE: To evaluate the internal consistency of the Hip disability and Osteoarthritis Outcome Score-Physical Function Short-form (HOOS-PS) and the Knee injury and Osteoarthritis Outcome Score-Physical Function Short-form (KOOS-PS) in total hip replacement (THR) and total knee (TKR) replacement....... Construct validity and responsiveness were compared to the Western Ontario McMaster Universities' Osteoarthritis Index (WOMAC) Likert 3.0 physical function (PF) subscale and the PF excluding the items in the short measures (PF-exclusions). METHODS: Participants completed the full HOOS or KOOS, measures...... of fatigue, anxiety, depression and the Chronic Pain Grade (CPG) pre-surgery and the HOOS or KOOS 6 months post-surgery. Internal consistency for the HOOS-PS and KOOS-PS was calculated using Cronbach's alpha. For construct validity, it was hypothesized that correlations between the HOOS-PS or KOOS-PS and PF...

Breaking time-resolution limits in pulse radiolysis

International Nuclear Information System (INIS)

Yang Jinfeng; Kondoh, Takafumi; Norizawa, Kimihiro; Yoshida, Yoichi; Tagawa, Seiichi

2009-01-01

Pulse radiolysis, which is a time-resolved stroboscopic method based on ultrashort electron pulse and ultrashort analyzing light, is widely used for the study of the chemical kinetics and radiation primary processes or reactions. Although it has become possible to use femtosecond-pulse electron beam and femtosecond laser light in pulse radiolysis, the resolution is limited by the difference in group velocities of the electrons and the light in sample. In this contribution, we introduce a concept of equivalent velocity spectroscopy (EVS) into pulse radiolysis and demonstrate the methodology experimentally. In EVS, both the electron and the analyzing light pulses precisely overlap at every point in the sample and throughout the propagation time by rotating the electron pulse. The advance allows us to overcome the resolution degradation due to the different group velocity. We also present a method for measuring the rotated angle of the electron pulse and a technique for rotating the electron pulse with a deflecting cavity.

Diamond detector time resolution for large angle tracks

Energy Technology Data Exchange (ETDEWEB)

Chiodini, G., E-mail: chiodini@le.infn.it [INFN - Sezione di Lecce (Italy); Fiore, G.; Perrino, R. [INFN - Sezione di Lecce (Italy); Pinto, C.; Spagnolo, S. [INFN - Sezione di Lecce (Italy); Dip. di Matematica e Fisica “Ennio De Giorgi”, Uni. del Salento (Italy)

2015-10-01

The applications which have stimulated greater interest in diamond sensors are related to detectors close to particle beams, therefore in an environment with high radiation level (beam monitor, luminosity measurement, detection of primary and secondary-interaction vertices). Our aims is to extend the studies performed so far by developing the technical advances needed to prove the competitiveness of this technology in terms of time resolution, with respect to more usual ones, which does not guarantee the required tolerance to a high level of radiation doses. In virtue of these goals, measurements of diamond detector time resolution with tracks incident at different angles are discussed. In particular, preliminary testbeam results obtained with 5 GeV electrons and polycrystalline diamond strip detectors are shown.

High-resolution seismic wave propagation using local time stepping

KAUST Repository

Peter, Daniel; Rietmann, Max; Galvez, Percy; Ampuero, Jean Paul

2017-01-01

High-resolution seismic wave simulations often require local refinements in numerical meshes to accurately capture e.g. steep topography or complex fault geometry. Together with explicit time schemes, this dramatically reduces the global time step

The Cherenkov correlated timing detector: beam test results from quartz and acrylic bars

International Nuclear Information System (INIS)

Kichimi, H.; Sugaya, Y.; Yamaguchi, H.; Yoshimura, Y.; Kanda, S.; Olsen, S.; Ueno, K.; Varner, G.; Bergfeld, T.; Bialek, J.; Lorenc, J.; Palmer, M.; Rudnick, G.; Selen, M.; Auran, T.; Boyer, V.; Honscheid, K.; Tamura, N.; Yoshimura, K.; Lu, C.; Marlow, D.; Mindas, C.; Prebys, E.; Asai, M.; Kimura, A.; Hayashi, S.

1996-01-01

Several prototypes of a Cherenkov correlated timing (CCT) detector have been tested at the KEK-PS test beam line. We describe the results for Cherenkov light yields and timing characteristics from quartz and acrylic bar prototypes. A Cherenkov angle resolution is found to be 15 mrad at a propagation distance of 100 cm with a 2 cm thick quartz bar prototype. (orig.)

ELECTRON BUNCH CHARACTERIZATION WITH SUBPICOSECOND RESOLUTION USING ELECTRO-OPTIC TECHNIQUE

International Nuclear Information System (INIS)

SEMERTZIDIS, Y.K.; CASTILLO, V.; LARSEN, R.; LAZARUS, D.M.; NIKAS, D.; OZBEN, C.; SRINIVASAN-RAO, T.; STILLMAN, A.; TSANG, T.; KOWALSKI, L.

2001-01-01

In the past decade, the bunch lengths of electrons in accelerators have decreased dramatically and are in the range off a few millimeters. Measurement of the length as well as the longitudinal profile of these short bunches have been a topic of research in a number of institutions. One of the techniques uses the electric field induced by the passage of electrons in the vicinity of a birefringent crystal to change its optical characteristics. Well-established electro-optic techniques can then be used to measure the temporal characteristics of the electron bunch. The inherent fast response of the crystal facilitates the measurement to femtosecond time resolution. However, the resolution in experiments so far has been limited to 70 ps, by the bandwidth of the detection equipment. Use of a streak camera can improve this resolution to a few picoseconds. In this paper we present a novel, non-invasive, single-shot approach to improve the resolution to tens of femtoseconds so that sub mm bunch length can be measured

PS, SL and LHC Auditoria change names

CERN Multimedia

2003-01-01

Following the replacement of the PS, SL and LHC Divisions by the AB and AT Divisions, the Auditoria are also changing their names. PS Auditorium is renamed AB Meyrin SL Auditorium is renamed AB Prévessin LHC Auditorium is renamed AT

Human hair follicle pluripotent stem (hfPS) cells promote regeneration of peripheral-nerve injury: an advantageous alternative to ES and iPS cells.

Science.gov (United States)

Amoh, Yasuyuki; Kanoh, Maho; Niiyama, Shiro; Hamada, Yuko; Kawahara, Katsumasa; Sato, Yuichi; Hoffman, Robert M; Katsuoka, Kensei

2009-08-01

The optimal source of stem cells for regenerative medicine is a major question. Embryonic stem (ES) cells have shown promise for pluripotency but have ethical issues and potential to form teratomas. Pluripotent stem cells have been produced from skin cells by either viral-, plasmid- or transposon-mediated gene transfer. These stem cells have been termed induced pluripotent stem cells or iPS cells. iPS cells may also have malignant potential and are inefficiently produced. Embryonic stem cells may not be suited for individualized therapy, since they can undergo immunologic rejection. To address these fundamental problems, our group is developing hair follicle pluripotent stem (hfPS) cells. Our previous studies have shown that mouse hfPS cells can differentiate to neurons, glial cells in vitro, and other cell types, and can promote nerve and spinal cord regeneration in vivo. hfPS cells are located above the hair follicle bulge in what we have termed the hfPS cell area (hfPSA) and are nestin positive and keratin 15 (K-15) negative. Human hfPS cells can also differentiate into neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. In the present study, human hfPS cells were transplanted in the severed sciatic nerve of the mouse where they differentiated into glial fibrillary-acidic-protein (GFAP)-positive Schwann cells and promoted the recovery of pre-existing axons, leading to nerve generation. The regenerated nerve recovered function and, upon electrical stimulation, contracted the gastrocnemius muscle. The hfPS cells can be readily isolated from the human scalp, thereby providing an accessible, autologous and safe source of stem cells for regenerative medicine that have important advantages over ES or iPS cells. (c) 2009 Wiley-Liss, Inc.

RPCs: the choreography of precise timing

CERN Document Server

Boyko, I; Dydak, F; Elagin, A; Gostkin, M; Koreshev, V; Nefedov, Y; Nikolaev, K; Wotschack, J; Zhemchugov, A

2005-01-01

We present a comprehensive overview of all steps to be taken in order to achieve precise timing of the HARP RPCs. After briefly recalling the salient features of the RPC mechanics and electronics, we discuss the results from the dedicated calibration scan in a -12 GeV/c beam which gave valuable first information on efficiency and uniformity of response, charge attenuation, the global time slewing correction, effective strip transit time, relative delays between strips of a pad, and intrinsic time resolution. The latter was determined to be ~140 ps which sets the scale for the control of systematic effects, so as not to deteriorate significantly the overall time-of-flight resolution of the RPCs. From physics data, primarily from `neutral' and `charged' hits in RPC overlap regions, further refinements are derived, in particular padring-specific modifications of the global time slewing correction, and manifestations of the `knock-on' and noise' effects. With a view to a bias-free determination of pad-specific t0...

Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution

Directory of Open Access Journals (Sweden)

M. Kozina

2014-05-01

Full Text Available We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,TiO3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics.

Nouvelle application de control des cavités 200 MHz RF du PS (CERN)

CERN Document Server

Cotte, D

2011-01-01

Le système Radio Fréquence (RF) 200MHz du PS est un outil essentiel pour la préparation des faisceaux haute intensité du PS. Dans l’anneau PS on trouve 6 cavités 200 MHz utilisées pour contrôler : • l’émittance longitudinale des « bunches » • le processus de « Rebunching » du faisceau avant de l’envoyer au SPS. Chaque cavité est pilotée par des événements appelés « timing » et suit une fonction de tension programmée. Cependant, l’électronique utilisée pour piloter les cavités 200 MHz du PS est obsolète et sa fiabilité non garantie pour cause du manque de pièces de rechange. Ce document décrit le fonctionnement du nouveau programme d’application qui fait abstraction de l’ancienne matrice hardware. Elle suit les recommandations décrites dans l’étude d’une nouvelle structure pour le système RF 200MHz du PS. [1

Development of subpicosecond pulse radiolysis system

CERN Document Server

Kozawa, T; Miki, M; Yamamoto, T; Suemine, S; Yoshida, Y; Tagawa, S

2000-01-01

The highest time resolution of the pulse radiolysis had remained about 30 ps since the late 1960s. To make clear the primary processes in the radiation chemistry and physics within 30 ps, we developed a stroboscopic pulse radiolysis system for the absorption spectroscopy with the time resolution of 2.0 ps (10-90% rise time). The time resolution of 2.0 ps was estimated from the time-dependent behavior of the hydrated electrons. The system consists of a subpicosecond electron linac as an irradiation source, a femtosecond laser as an analyzing light and a jitter compensation system.

Psühhodraama - spontaansuse kool / Taimi Elenurm

Index Scriptorium Estoniae

Elenurm, Taimi

2010-01-01

Viinis ja New Yorgis tegutsenud psühhiaatri Jakob Levy Moreno loodud psühhodraamast, mis võimaldab rollimängu kaudu näha ennast läbi teiste silmade, aga ka vabaneda pingetest andes võimaluse käituda teisiti kui tavaelus

State of the art timing in TOF-PET detectors with LuAG, GAGG and L(Y)SO scintillators of various sizes coupled to FBK-SiPMs

CERN Document Server

Gundacker, S.; Auffray, E.; Ferri, A.; Gola, A.; Nemallapudi, M.V.; Paternoster, G.; Piemonte, C.; Lecoq, P.

2016-01-01

Time of flight (TOF) in positron emission tomography (PET) has experienced a revival of interest after its first introduction in the eighties. This is due to a significant progress in solid state photodetectors (SiPMs) and newly developed scintillators (LSO and its derivatives). Latest developments at Fondazione Bruno Kessler (FBK) lead to the NUV-HD SiPM with a very high photon detection efficiency of around 55%. Despite the large area of 4×4 mm2 it achieves a good single photon time resolution (SPTR) of 180±5ps FWHM. Coincidence time resolution (CTR) measurements using LSO:Ce codoped with Ca scintillators yield best values of 73±2ps FWHM for 2×2×3 mm3 and 117±3ps for 2×2×20 mm3 crystal sizes. Increasing the crystal cross-section from 2×2 mm2 to 3×3 mm2 a non negligible CTR deterioration of approximately 7ps FWHM is observed. Measurements with LSO:Ce codoped Ca and LYSO:Ce scintillators with various cross-sections (1×1 mm2 - 4×4 mm2) and lengths (3mm - 30mm) will be a basis for discussing on how ...

A combined time-of-flight and depth-of-interaction detector for total-body positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Berg, Eric, E-mail: eberg@ucdavis.edu; Roncali, Emilie; Du, Junwei; Cherry, Simon R. [Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, California 95616 (United States); Kapusta, Maciej [Molecular Imaging, Siemens Healthcare, Knoxville, Tennessee 37932 (United States)

2016-02-15

Purpose: In support of a project to build a total-body PET scanner with an axial field-of-view of 2 m, the authors are developing simple, cost-effective block detectors with combined time-of-flight (TOF) and depth-of-interaction (DOI) capabilities. Methods: This work focuses on investigating the potential of phosphor-coated crystals with conventional PMT-based block detector readout to provide DOI information while preserving timing resolution. The authors explored a variety of phosphor-coating configurations with single crystals and crystal arrays. Several pulse shape discrimination techniques were investigated, including decay time, delayed charge integration (DCI), and average signal shapes. Results: Pulse shape discrimination based on DCI provided the lowest DOI positioning error: 2 mm DOI positioning error was obtained with single phosphor-coated crystals while 3–3.5 mm DOI error was measured with the block detector module. Minimal timing resolution degradation was observed with single phosphor-coated crystals compared to uncoated crystals, and a timing resolution of 442 ps was obtained with phosphor-coated crystals in the block detector compared to 404 ps without phosphor coating. Flood maps showed a slight degradation in crystal resolvability with phosphor-coated crystals; however, all crystals could be resolved. Energy resolution was degraded by 3%–7% with phosphor-coated crystals compared to uncoated crystals. Conclusions: These results demonstrate the feasibility of obtaining TOF–DOI capabilities with simple block detector readout using phosphor-coated crystals.

A combined time-of-flight and depth-of-interaction detector for total-body positron emission tomography

International Nuclear Information System (INIS)

Berg, Eric; Roncali, Emilie; Du, Junwei; Cherry, Simon R.; Kapusta, Maciej

2016-01-01

Purpose: In support of a project to build a total-body PET scanner with an axial field-of-view of 2 m, the authors are developing simple, cost-effective block detectors with combined time-of-flight (TOF) and depth-of-interaction (DOI) capabilities. Methods: This work focuses on investigating the potential of phosphor-coated crystals with conventional PMT-based block detector readout to provide DOI information while preserving timing resolution. The authors explored a variety of phosphor-coating configurations with single crystals and crystal arrays. Several pulse shape discrimination techniques were investigated, including decay time, delayed charge integration (DCI), and average signal shapes. Results: Pulse shape discrimination based on DCI provided the lowest DOI positioning error: 2 mm DOI positioning error was obtained with single phosphor-coated crystals while 3–3.5 mm DOI error was measured with the block detector module. Minimal timing resolution degradation was observed with single phosphor-coated crystals compared to uncoated crystals, and a timing resolution of 442 ps was obtained with phosphor-coated crystals in the block detector compared to 404 ps without phosphor coating. Flood maps showed a slight degradation in crystal resolvability with phosphor-coated crystals; however, all crystals could be resolved. Energy resolution was degraded by 3%–7% with phosphor-coated crystals compared to uncoated crystals. Conclusions: These results demonstrate the feasibility of obtaining TOF–DOI capabilities with simple block detector readout using phosphor-coated crystals

Ps 22 in Gospels’ interpretation of Passion

Directory of Open Access Journals (Sweden)

Sylwester Jędrzejewski

2012-09-01

Full Text Available Ps 22 is a piece of artistically high poetry, clear images and metaphors, historical and prophetic references. The conviction of biblical scholars that the New Testament writers has recognized in Ps 22 prophetic witness of passion, accompanies the Church from its beginnings. The words of Jesus on the cross, taken from Ps 22: 2, have a character of lamentable re-symbolization of the prayer of Israel. These words establish a theological answer in the form of suitable credo as well. Dramatic question “why?” is connected with a proclamation and identification “My God”. The personal experience of oppression and death is included by Jesus in the history of his nation and in the experience of God. Ps 22 in the Gospels’ passion context becomes a proclamation form of prayer and a very personal, expressed in such dramatic circumstances confession of the faith.

The time-of-flight detector of the DIRAC experiment

International Nuclear Information System (INIS)

Adeva, B.; Gallas, M.V.; Gomez, F.; Lopez-Agueera, A.; Nunez-Pardo, T.; Plo, M.; Rodriguez, A.M.; Rodriguez, X.M.; Saborido, J.J.; Santamarina, C.; Tobar, M.J.; Vazquez, P.

2002-01-01

The construction and performance of a large area time-of-flight detector for the DIRAC experiment at CERN is reported. With an average time resolution of 123 ps per counter at rates up to 1 MHz, it allows excellent separation of pπ - from π + π - pairs up to 4.6 GeV/c momentum, as well as of Coulomb-correlated pion pairs from accidentals. The optimization of scintillator material, photomultiplier performance and readout electronics is described

A CMOS delay locked loop and sub-nanosecond time-to-digital converter chip

International Nuclear Information System (INIS)

Santos, D.M.; Dow, S.F.; Flasck, J.M.; Levi, M.E.

1996-01-01

Phase-locked loops have been employed in the past to obtain sub-nanosecond time resolution in high energy physics and nuclear science applications. An alternative solution based on a delay-locked loop (DLL) is described. This solution allows for a very high level of integration yet still offers resolution in the sub-nanosecond regime. Two variations on this solution are outlined. A novel phase detector, based on the Mueller C-element, is used to implement a charge pump where the injected charge approaches zero as the loop approaches lock on the leading edge of an input clock reference. This greatly reduces timing jitter. In the second variation the loop locks to both the leading and trailing clock edges. In this second implementation, software coded layout generators are used to automatically layout a highly integrated, multichannel, time-to-digital converter (TDC) targeted for one specific frequency. The two circuits, DLL and TDC, are implemented in CMOS 1.2 microm and 0.8 microm technologies, respectively. Test results show a timing jitter of less than 30 ps for the DLL circuit and less than 190 ps integral and differential nonlinearity for the TDC circuit

Laboratory spectrum of the PS radical and related astronomical search

International Nuclear Information System (INIS)

Ohishi, M.; Yamamoto, S.; Saito, S.; Kawaguchi, K.; Suzuki, H.

1988-01-01

The millimeter-wave rotational spectrum of the PS radical (X 2Pi r) was observed in the laboratory for the first time in the frequency region of 79-293 GHz by discharging the mixture of PSCl3 and He. Some 44 lines were measured, and the rotational constant, the centrifugal distortion constant, the centrifugal distortion term of the spin-orbit coupling constant, the Lambda-type doubling constants, and the hyperfine coupling constants were determined. Based on the measured and calculated frequencies, an astronomical search for the interstellar and circumstellar PS radical was made without success in Orion KL, Sgr B2, L134N,IRC + 10216, VY CMa, and OH 231.8 + 4.2. 29 references

Fast-timing Capabilities of Silicon Sensors for the CMS High-Granularity Calorimeter at the High-Luminosity LHC

Science.gov (United States)

Akchurin, Nural; CMS Collaboration

2017-11-01

We report on the signal timing capabilities of thin silicon sensors when traversed by multiple simultaneous minimum ionizing particles (MIP). Three different planar sensors, 133, 211, and 285 μm thick in depletion thickness, have been exposed to high energy muons and electrons at CERN. We describe signal shape and timing resolution measurements as well as the response of these devices as a function of the multiplicity of MIPs. We compare these measurements to simulations where possible. We achieve better than 20 ps timing resolution for signals larger than a few tens of MIPs.

Time-of-flight electron energy loss spectroscopy using TM110 deflection cavities

Directory of Open Access Journals (Sweden)

W. Verhoeven

2016-09-01

Full Text Available We demonstrate the use of two TM110 resonant cavities to generate ultrashort electron pulses and subsequently measure electron energy losses in a time-of-flight type of setup. The method utilizes two synchronized microwave cavities separated by a drift space of 1.45 m. The setup has an energy resolution of 12 ± 2 eV FWHM at 30 keV, with an upper limit for the temporal resolution of 2.7 ± 0.4 ps. Both the time and energy resolution are currently limited by the brightness of the tungsten filament electron gun used. Through simulations, it is shown that an energy resolution of 0.95 eV and a temporal resolution of 110 fs can be achieved using an electron gun with a higher brightness. With this, a new method is provided for time-resolved electron spectroscopy without the need for elaborate laser setups or expensive magnetic spectrometers.

Real-life experience of using conventional disease-modifying anti-rheumatic drugs (DMARDs) in psoriatic arthritis (PsA). Retrospective analysis of the efficacy of methotrexate, sulfasalazine, and leflunomide in PsA in comparison to spondyloarthritides other than PsA and literature review of the use of conventional DMARDs in PsA

Science.gov (United States)

Roussou, Euthalia; Bouraoui, Aicha

2017-01-01

Objective With the aim of assessing the response to treatment with conventional disease-modifying anti-rheumatic drugs (DMARDs) used in patients with psoriatic arthritis (PsA), data on methotrexate, sulfasalazine (SSZ), and leflunomide were analyzed from baseline and subsequent follow-up (FU) questionnaires completed by patients with either PsA or other spondyloarthritides (SpAs). Material and Methods A single-center real-life retrospective analysis was performed by obtaining clinical data via questionnaires administered before and after treatment. The indices used were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Function Index (BASFI), wellbeing (WB), and treatment effect (TxE). The indices measured at baseline were compared with those measured on one occasion in a FU visit at least 1 year later. Results A total of 73 patients, 51 with PsA (mean age 49.8±12.8 years; male-to-female ratio [M:F]=18:33) and 22 with other SpAs (mean age 50.6±16 years; M:F=2:20), were studied. BASDAI, BASFI, and WB displayed consistent improvements during FU assessments in both PsA patients and controls in comparison to baseline values. SSZ exhibited better efficacy as confirmed by TxE in both PsA patients and controls. ESR and CRP displayed no differences in either the PsA or the SpA group between the cases before and after treatment. Conclusion Real-life retrospective analysis of three DMARDs used in PsA (and SpAs other than PsA) demonstrated that all three DMARDs that were used brought about improvements in BASDAI, BASFI, TxE, and WB. However, the greatest improvements at FU were seen with SSZ use in both PsA and control cohorts. PMID:28293446

Spatio-temporal responses of Arabidopsis leaves in photosynthetic performance and metabolite contents to Burkholderia phytofirmans PsJN

Directory of Open Access Journals (Sweden)

Fan eSu

2016-03-01

Full Text Available A valuable strategy to improve crop yield consists in the use of plant growth-promoting rhizobacteria (PGPRs. However, the influence of PGPR colonization on plant physiology is largely unknown. PGPR Burkholderia phytofirmans strain PsJN (Bp PsJN colonized only Arabidopsis thaliana roots after seed or soil inoculation. Foliar bacteria were detected only after leaf infiltration. Since different bacterial times of presence and/or locations in host plant could lead to different plant physiological responses, photosynthesis and metabolite profiles in A. thaliana leaves were thus investigated following leaf, root or seed inoculation with Bp PsJN. Only Bp PsJN leaf colonization transiently decreased cyclic electron transport and effective quantum yield of photosystem I (PSI, and prevented a decrease in net photosynthesis and stomatal opening compared to the corresponding control. Metabolomic analysis revealed that soluble sugars, amino acids or their derivatives accumulated differently in all Bp PsJN-inoculated plants. Octanoic acid accumulated only in case of inoculated plants. Modifications in vitamin, organic acid such as tricarboxylic acid intermediates, and hormone amounts were dependent on bacterial time of presence and location. Additionally, a larger array of amino acids and hormones (auxin, cytokinin, abscisic acid were modified by seed inoculation with Bp PsJN. Our work thereby provides evidence that relative short-term inoculation with Bp PsJN altered physiological status of A.thaliana leaves, whereas long-term bacterization triggered modifications on a larger set of metabolites. Our data highlighted the changes displayed during this plant-microbe interaction to trigger physiological and metabolic responses that could explain the increase in plant growth or stress tolerance conferred by the presence of Bp PsJN.

High-resolution near real-time drought monitoring in South Asia

OpenAIRE

Aadhar, Saran; Mishra, Vimal

2017-01-01

Drought in South Asia affect food and water security and pose challenges for millions of people. For policy-making, planning, and management of water resources at sub-basin or administrative levels, high-resolution datasets of precipitation and air temperature are required in near-real time. We develop a high-resolution (0.05°) bias-corrected precipitation and temperature data that can be used to monitor near real-time drought conditions over South Asia. Moreover, the dataset can be used to m...

Comparison of the effect of plasma treatment and gamma ray irradiation on PS-Cu nanocomposite films surface

Science.gov (United States)

Farag, O. F.

2018-06-01

Polystyrene-copper (PS-Cu) nanocomposite films were treated with DC N2 plasma and gamma rays irradiations. The plasma treatment of PS-Cu film surface was carried out at different treatment times, gas pressure 0.4 Torr and the applied power 3.5 W. On the other hand, the treatment with gamma rays irradiation were carried out at irradiation doses 10, 30 and 50 kGy. The induced changes in surface properties of PS-Cu films were investigated with UV-viss spectroscopy, scanning electron microscopy (SEM) and FTIR spectroscopy techniques. In addition, the wettability property, surface free energy, spreading coefficient and surface roughness of the treated samples were studied by measuring the contact angle. The UV-viss spectroscopy analysis revealed that the optical band gap decreases with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. SEM observations showed that the particle size of copper particles was increased with increasing the treatment time and the irradiation dose, but gamma treatment changes the copper particles size from nano scale to micro scale. The contact angle measurements showing that the wettability property, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples were increased remarkably with increasing the treatment time and the irradiation dose for plasma and gamma treatments, respectively. The contact angle, surface free energy, spreading coefficient and surface roughness of the treated PS-Cu samples are more influenced by plasma treatment than gamma treatment.

Administration of Bifidobacterium breve PS12929 and Lactobacillus salivarius PS12934, Two Strains Isolated from Human Milk, to Very Low and Extremely Low Birth Weight Preterm Infants: A Pilot Study

Directory of Open Access Journals (Sweden)

Laura Moles

2015-01-01

Full Text Available The preterm infant gut has been described as immature and colonized by an aberrant microbiota. Therefore, the use of probiotics is an attractive practice in hospitals to try to reduce morbidity and mortality in this population. The objective of this pilot study was to elucidate if administration of two probiotic strains isolated from human milk to preterm infants led to their presence in feces. In addition, the evolution of a wide spectrum of immunological compounds, including the inflammatory biomarker calprotectin, in both blood and fecal samples was also assessed. For this purpose, five preterm infants received two daily doses (~109 CFU of a 1 : 1 mixture of Bifidobacterium breve PS12929 and Lactobacillus salivarius PS12934. Bacterial growth was detected by culture-dependent techniques in all the fecal samples. The phylum Firmicutes dominated in nearly all fecal samples while L. salivarius PS12934 was detected in all the infants at numerous sample collection points and B. breve PS12929 appeared in five fecal samples. Finally, a noticeable decrease in the fecal calprotectin levels was observed along time.

Administration of Bifidobacterium breve PS12929 and Lactobacillus salivarius PS12934, two strains isolated from human milk, to very low and extremely low birth weight preterm infants: a pilot study.

Science.gov (United States)

Moles, Laura; Escribano, Esperanza; de Andrés, Javier; Montes, María Teresa; Rodríguez, Juan M; Jiménez, Esther; Sáenz de Pipaón, Miguel; Espinosa-Martos, Irene

2015-01-01

The preterm infant gut has been described as immature and colonized by an aberrant microbiota. Therefore, the use of probiotics is an attractive practice in hospitals to try to reduce morbidity and mortality in this population. The objective of this pilot study was to elucidate if administration of two probiotic strains isolated from human milk to preterm infants led to their presence in feces. In addition, the evolution of a wide spectrum of immunological compounds, including the inflammatory biomarker calprotectin, in both blood and fecal samples was also assessed. For this purpose, five preterm infants received two daily doses (~10(9) CFU) of a 1:1 mixture of Bifidobacterium breve PS12929 and Lactobacillus salivarius PS12934. Bacterial growth was detected by culture-dependent techniques in all the fecal samples. The phylum Firmicutes dominated in nearly all fecal samples while L. salivarius PS12934 was detected in all the infants at numerous sample collection points and B. breve PS12929 appeared in five fecal samples. Finally, a noticeable decrease in the fecal calprotectin levels was observed along time.

Time-resolved photon echoes from donor-bound excitons in ZnO epitaxial layers

Science.gov (United States)

Poltavtsev, S. V.; Kosarev, A. N.; Akimov, I. A.; Yakovlev, D. R.; Sadofev, S.; Puls, J.; Hoffmann, S. P.; Albert, M.; Meier, C.; Meier, T.; Bayer, M.

2017-07-01

The coherent optical response from 140 nm and 65 nm thick ZnO epitaxial layers is studied using four-wave-mixing spectroscopy with picosecond temporal resolution. Resonant excitation of neutral donor-bound excitons results in two-pulse and three-pulse photon echoes. For the donor-bound A exciton (D0XA ) at temperature of 1.8 K we evaluate optical coherence times T2=33 -50 ps corresponding to homogeneous line widths of 13 -19 μ eV , about two orders of magnitude smaller as compared with the inhomogeneous broadening of the optical transitions. The coherent dynamics is determined mainly by the population decay with time T1=30 -40 ps, while pure dephasing is negligible. Temperature increase leads to a significant shortening of T2 due to interaction with acoustic phonons. In contrast, the loss of coherence of the donor-bound B exciton (D0XB ) is significantly faster (T2=3.6 ps ) and governed by pure dephasing processes.

The multigap resistive plate chamber as time-of-flight detector for the STAR experiment at RHIC

International Nuclear Information System (INIS)

Lamas V, J.

2002-01-01

The multigap resistive plate chamber (MRPC) is a suitable candidate for the time-of-flight system for the STAR experiment at RHIC at the BNL. A time resolution of 50 ps with an efficiency of 98% has been measured with MRPCs composed of 6 gas gaps of 220 μm. Results obtained during the year 2000 are reported here

Large area spark counters with fine time and position resolution

International Nuclear Information System (INIS)

Ogawa, A.; Atwood, W.B.; Fujiwara, N.; Pestov, Yu.N.; Sugahara, R.

1983-10-01

Spark counters trace their history back over three decades but have been used in only a limited number of experiments. The key properties of these devices include their capability of precision timing (at the sub 100 ps level) and of measuring the position of the charged particle to high accuracy. At SLAC we have undertaken a program to develop these devices for use in high energy physics experiments involving large detectors. A spark counter of size 1.2 m x 0.1 m has been constructed and has been operating continuously in our test setup for several months. In this talk I will discuss some details of its construction and its properties as a particle detector. 14 references

Frontend electronics for high-precision single photo-electron timing using FPGA-TDCs

Science.gov (United States)

Cardinali, M.; Dzyhgadlo, R.; Gerhardt, A.; Götzen, K.; Hohler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Ugur, C.; Zühlsdorf, M.; Dodokhov, V. Kh.; Britting, A.; Eyrich, W.; Lehmann, A.; Uhlig, F.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Corell, O.; Ferretti Bondy, M. I.; Hoek, M.; Lauth, W.; Rosner, C.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

2014-12-01

The next generation of high-luminosity experiments requires excellent particle identification detectors which calls for Imaging Cherenkov counters with fast electronics to cope with the expected hit rates. A Barrel DIRC will be used in the central region of the Target Spectrometer of the planned PANDA experiment at FAIR. A single photo-electron timing resolution of better than 100 ps is required by the Barrel DIRC to disentangle the complicated patterns created on the image plane. R&D studies have been performed to provide a design based on the TRB3 readout using FPGA-TDCs with a precision better than 20 ps RMS and custom frontend electronics with high-bandwidth pre-amplifiers and fast discriminators. The discriminators also provide time-over-threshold information thus enabling walk corrections to improve the timing resolution. Two types of frontend electronics cards optimised for reading out 64-channel PHOTONIS Planacon MCP-PMTs were tested: one based on the NINO ASIC and the other, called PADIWA, on FPGA discriminators. Promising results were obtained in a full characterisation using a fast laser setup and in a test experiment at MAMI, Mainz, with a small scale DIRC prototype.

Time and Frequency Localized Pulse Shape for Resolution Enhancement in STFT-BOTDR

Directory of Open Access Journals (Sweden)

Linqing Luo

2016-01-01

Full Text Available Short-Time Fourier Transform-Brillouin Optical Time-Domain Reflectometry (STFT-BOTDR implements STFT over the full frequency spectrum to measure the distributed temperature and strain along the optic fiber, providing new research advances in dynamic distributed sensing. The spatial and frequency resolution of the dynamic sensing are limited by the Signal to Noise Ratio (SNR and the Time-Frequency (T-F localization of the input pulse shape. T-F localization is fundamentally important for the communication system, which suppresses interchannel interference (ICI and intersymbol interference (ISI to improve the transmission quality in multicarrier modulation (MCM. This paper demonstrates that the T-F localized input pulse shape can enhance the SNR and the spatial and frequency resolution in STFT-BOTDR. Simulation and experiments of T-F localized different pulses shapes are conducted to compare the limitation of the system resolution. The result indicates that rectangular pulse should be selected to optimize the spatial resolution and Lorentzian pulse could be chosen to optimize the frequency resolution, while Gaussian shape pulse can be used in general applications for its balanced performance in both spatial and frequency resolution. Meanwhile, T-F localization is proved to be useful in the pulse shape selection for system resolution optimization.

Time and spectrum-resolving multiphoton correlator for 300–900 nm

Energy Technology Data Exchange (ETDEWEB)

Johnsen, Kelsey D.; Thibault, Marilyne; Jennewein, Thomas [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Kolenderski, Piotr, E-mail: kolenderski@fizyka.umk.pl [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Faculty of Physics, Astronomy and Informatics, Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Scarcella, Carmelo; Tosi, Alberto [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

2014-10-14

We demonstrate a single-photon sensitive spectrometer in the visible range, which allows us to perform time-resolved and multi-photon spectral correlation measurements at room temperature. It is based on a monochromator composed of two gratings, collimation optics, and an array of single photon avalanche diodes. The time resolution can reach 110 ps and the spectral resolution is 2 nm/pixel, limited by the design of the monochromator. This technique can easily be combined with commercial monochromators and can be useful for joint spectrum measurements of two photons emitted in the process of parametric down conversion, as well as time-resolved spectrum measurements in optical coherence tomography or medical physics applications.

Updating the Psoriatic Arthritis (PsA) Core Domain Set

DEFF Research Database (Denmark)

Orbai, Ana-Maria; de Wit, Maarten; Mease, Philip J

2017-01-01

OBJECTIVE: To include the patient perspective in accordance with the Outcome Measures in Rheumatology (OMERACT) Filter 2.0 in the updated Psoriatic Arthritis (PsA) Core Domain Set for randomized controlled trials (RCT) and longitudinal observational studies (LOS). METHODS: At OMERACT 2016, research...... conducted to update the PsA Core Domain Set was presented and discussed in breakout groups. The updated PsA Core Domain Set was voted on and endorsed by OMERACT participants. RESULTS: We conducted a systematic literature review of domains measured in PsA RCT and LOS, and identified 24 domains. We conducted...... and breakout groups at OMERACT 2016 in which findings were presented and discussed. The updated PsA Core Domain Set endorsed with 90% agreement by OMERACT 2016 participants included musculoskeletal disease activity, skin disease activity, fatigue, pain, patient's global assessment, physical function, health...

NaPdPS{sub 4} and RbPdPS{sub 4}: systems with infinite straight ((1)/({infinity}))[PdPS{sub 4}]{sup -} chains soluble in polar solvents and the structure of cubic RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace}

Energy Technology Data Exchange (ETDEWEB)

Coste, Servane; Hanko, Jason; Bujoli-Doeuff, Martine; Louarn, Guy; Evain, Michel; Brec, Raymond; Alonso, Bruno; Jobic, S; Kanatzidis, Mercouri G

2003-11-01

The synthesis, crystal structures, chemical and spectroscopic properties of NaPdPS{sub 4}, RbPdPS{sub 4}, and RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} are described. NaPdPS{sub 4}, RbPdPS{sub 4}, are isostructural and crystallize in the tetragonal system I4/mcm with cell parameters a=7.3074(8) A, c=12.2308(14) A and a=8.2954(3) A, c=12.2284(4) A respectively. RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} is cubic, space group Pm-3n and a=12.0042(2) A. All compounds contain the same ((1)/({infinity}))[PdPS{sub 4}]{sup -} chains made of alternating square planar Pd{sup 2+} cations and tetrahedral [PS{sub 4}]{sup 3-} anions. RbPdPS{sub 4}{l_brace}Rb{sub 0.33}P{sub 0.4}S{sub 2.23}O{sub x}{r_brace} contains co-crystallized highly disordered molecular species encapsulated within [Rb{sub 8}] cubic cavities. Spectroscopic solid state {sup 31}P NMR, infrared and Raman data as well as elemental analysis suggest that these species could be S{sub n}{sup 2-} (n=3 or 4) anions and possibly cationic [P{sub 4}S{sub 6}O]{sup 6+} fragments. NaPdPS{sub 4} and RbPdPS{sub 4} exhibit exfoliative dissolution in polar solvents giving rise to solutions that show signs of complex fluid behavior.

A low dead time vernier delay line TDC implemented in an Actel flash-based FPGA

International Nuclear Information System (INIS)

Qin Xi; Feng Changqing; Zhang Deliang; Zhao Lei; Liu Shubin; An Qi

2013-01-01

In this paper, a high precision vernier delay line (VDL) TDC (Time-to-Digital Converter) in an Actel flash-based Field-Programmable-Gate-Arrays A3PE1500 is implemented, achieving a resolution of 16.4-ps root mean square value or 42-ps averaged bin size. The TDC has a dead time of about 200 ns while the dynamic range is 655.36 Vs. The double delay lines method is employed to cut the dead time in half to improve its performance. As the bin size of the TDC is dependent on temperature, a compensation algorithm is adopted as temperature drift correction, and the TDC shows satisfying performance in a temperature range from -5℃ to +55℃. (authors)

Understanding Laterally Varying Path Effects on P/S Ratios and their Effectiveness for Event Discrimination at Local Distances

Science.gov (United States)

Pyle, M. L.; Walter, W. R.

2017-12-01

Discrimination between underground explosions and naturally occurring earthquakes is an important endeavor for global security and test-ban treaty monitoring, and ratios of seismic P to S-wave amplitudes at regional distances have proven to be an effective discriminant. The use of the P/S ratio is rooted in the idea that explosive sources should theoretically only generate compressional energy. While, in practice, shear energy is observed from explosions, generally when corrections are made for magnitude and distance, P/S ratios from explosions are higher than those from surrounding earthquakes. At local distances (chemical explosions at the Nevada National Security Site (NNSS) designed to improve our understanding and modeling capabilities of shear waves generated by explosions. Phase I consisted of 5 explosions in granite and Phase II will move to a contrasting dry alluvium geology. We apply a high-resolution 2D attenuation model to events near the NNSS to examine what effect path plays in local P/S ratios, and how well an earthquake-derived model can account for shallower explosion paths. The model incorporates both intrinsic attenuation and scattering effects and extends to 16 Hz, allowing us to make lateral path corrections and consider high-frequency ratios. Preliminary work suggests that while 2D path corrections modestly improve earthquake amplitude predictions, explosion amplitudes are not well matched, and so P/S ratios do not necessarily improve. Further work is needed to better understand the uses and limitation of 2D path corrections for local P/S ratios.

An HDAC2-TET1 switch at distinct chromatin regions significantly promotes the maturation of pre-iPS to iPS cells

Science.gov (United States)

Wei, Tingyi; Chen, Wen; Wang, Xiukun; Zhang, Man; Chen, Jiayu; Zhu, Songcheng; Chen, Long; Yang, Dandan; Wang, Guiying; Jia, Wenwen; Yu, Yangyang; Duan, Tao; Wu, Minjuan; Liu, Houqi; Gao, Shaorong; Kang, Jiuhong

2015-01-01

The maturation of induced pluripotent stem cells (iPS) is one of the limiting steps of somatic cell reprogramming, but the underlying mechanism is largely unknown. Here, we reported that knockdown of histone deacetylase 2 (HDAC2) specifically promoted the maturation of iPS cells. Further studies showed that HDAC2 knockdown significantly increased histone acetylation, facilitated TET1 binding and DNA demethylation at the promoters of iPS cell maturation-related genes during the transition of pre-iPS cells to a fully reprogrammed state. We also found that HDAC2 competed with TET1 in the binding of the RbAp46 protein at the promoters of maturation genes and knockdown of TET1 markedly prevented the activation of these genes. Collectively, our data not only demonstrated a novel intrinsic mechanism that the HDAC2-TET1 switch critically regulates iPS cell maturation, but also revealed an underlying mechanism of the interplay between histone acetylation and DNA demethylation in gene regulation. PMID:25934799

Motor preparation is modulated by the resolution of the response timing information.

Science.gov (United States)

Carlsen, Anthony N; Mackinnon, Colum D

2010-03-31

In the present experiment, the temporal predictability of response time was systematically manipulated to examine its effect on the time course of motor pre-programming and release of the intended movement by an acoustic startle stimulus. Participants performed a ballistic right wrist extension task in four different temporal conditions: 1) a variable foreperiod simple RT task, 2) a fixed foreperiod simple RT task, 3) a low resolution countdown anticipation-timing task, and 4) a high resolution anticipation-timing task. For each task, a startling acoustic stimulus (124dB) was presented at several intervals prior to the "go" signal ("go" -150ms, -500ms, and -1500ms). Results from the startle trials showed that the time course of movement pre-programming was affected by the temporal uncertainty of the imperative "go" cue. These findings demonstrate that the resolution of the timing information regarding the response cue has a marked effect on the timing of movement preparation such that under conditions of low temporal resolution, participants plan the movement well in advance in accordance with the anticipated probability of onset of the cue, whereas movement preparation is delayed until less than 500ms prior to response time when continuous temporal information is provided. Copyright 2010 Elsevier B.V. All rights reserved.

Package-friendly piezoresistive pressure sensors with on-chip integrated packaging-stress-suppressed suspension (PS3) technology

International Nuclear Information System (INIS)

Wang, Jiachou; Li, Xinxin

2013-01-01

An on-chip integrated packaging-stress-suppressed suspension (PS 3 ) technology for a packaging-stress-free pressure sensor is proposed and developed. With a MIS (microholes interetch and sealing) micromachining process implemented only from the front-side of a single-side polished (1 1 1) silicon wafer, a compact cantilever-shaped PS 3 is on-chip integrated surrounding a piezoresistive pressure-sensing structure to provide a packaging-process/substrate-friendly method for low-cost but high-performance sensor applications. With the MIS process, the chip size of the PS 3 -enclosed pressure sensor is as small as 0.8 mm × 0.8 mm. Compared with a normal pressure sensor without PS 3 (but with an identical pressure-sensing structure), the proposed pressure sensor has the same sensitivity of 0.046 mV kPa −1 (3.3 V) −1 . However, without using the thermal compensation technique, a temperature coefficient of offset of only 0.016% °C −1 FS is noted for the sensor with PS 3 , which is about 15 times better than that for the sensor without PS 3 . Featuring effective isolation and elimination of the influence from packaging stress, the PS 3 technique is promising to be widely used for packaging-friendly mechanical sensors. (paper)

Nearly penalty-free, less than 4 ps supercontinuum Gbit/s pulse generation over 1535-1560 nm

Science.gov (United States)

Morioka, T.; Kawanishi, S.; Mori, K.; Saruwatari, M.

1994-05-01

Nearly penalty-free less than 4ps supercontinuum WDM pulses are generated at 6.3 Gbit/s over 1535-1560 nm for the first time using a 200 nm superbroadened supercontinuum in an optical fibre pumped by 1.7 W, 3.3 ps, 1542 nm short pulses from an Er(3+)-doped fibre ring laser.

PS overcomes two serious magnet failures

CERN Multimedia

Maximilien Brice

2003-01-01

Two magnets and a bus bar connection in the PS were found to be faulty during high-voltage tests at the end of the accelerator shutdown. A five-week repair schedule was quickly devised. A team of mechanics, technicians and engineers worked at full speed to replace the faulty magnets, succeeding in limiting the delay of the accelerators' spring start-up to two weeks. Here we see the PS magnet string awaiting the replacement no. 6 magnet.

Optically isolated electronic trigger system for experiments on a subnanosecond time scale with a pulsed Van de Graaff electron accelerator

International Nuclear Information System (INIS)

Luthjens, L.H.; Vermeulen, M.J.W.; Hom, M.L.

1980-01-01

An optically isolated electronic trigger system for a pulsed Van de Graaff electron accelerator, producing an external pretrigger pulse 75 ns before arrival of the electron pulse at the target, is described. The total time jitter between trigger signal and electron pulse is 50 ps. The measurement of optical and electrical transients on a subnanosecond time scale with a sequential sampling oscilloscope is demonstrated. The contribution of various parts of the equipment to the total jitter is discussed. Those contributions to the jitter due to the electron transit time fluctuations in the accelerator assuming a constant acceleration voltage gradient and to the shot noise in the photomultiplier detector of the trigger system are calculated to be 5 ps and 12 to 21 ps respectively. Comparison with the experimental results leads to the conclusion that a considerable part of the total jitter may be attributed to acceleration voltage gradient fluctuations, to accelerator vibrations and possibly to density fluctuations in the insulation gas. Possible improvements of the trigger system are discussed. The apparatus is used for pulse radiolysis experiments with subnanosecond time resolution down to 100 ps in combination with subnanosecond time duration electron pulses

PS Control Room

CERN Multimedia

CERN PhotoLab

1963-01-01

The good old PS Control Room, all manual. For each parameter, a knob or a button to control it; for each, a light or meter or oscilloscope to monitor it; carefully written pages serve as the data bank; phones and intercom for communication. D.Dekkers is at the microphone, M.Valvini sits in front.

A high time resolution x-ray diagnostic on the Madison Symmetric Torus

Science.gov (United States)

DuBois, Ami M.; Lee, John David; Almagri, Abdulgadar F.

2015-07-01

A new high time resolution x-ray detector has been installed on the Madison Symmetric Torus (MST) to make measurements around sawtooth events. The detector system is comprised of a silicon avalanche photodiode, a 20 ns Gaussian shaping amplifier, and a 500 MHz digitizer with 14-bit sampling resolution. The fast shaping time diminishes the need to restrict the amount of x-ray flux reaching the detector, limiting the system dead-time. With a much higher time resolution than systems currently in use in high temperature plasma physics experiments, this new detector has the versatility to be used in a variety of discharges with varying flux and the ability to study dynamics on both slow and fast time scales. This paper discusses the new fast x-ray detector recently installed on MST and the improved time resolution capabilities compared to the existing soft and hard x-ray diagnostics. In addition to the detector hardware, improvements to the detector calibration and x-ray pulse identification software, such as additional fitting parameters and a more sophisticated fitting routine are discussed. Finally, initial data taken in both high confinement and standard reversed-field pinch plasma discharges are compared.

Prognostic significance of cytosolic pS2 content in ovarian tumors

International Nuclear Information System (INIS)

Raigoso, P.; Allende, T.; Zeidan, N.; Llana, B.; Bernardo, L.; Roiz, C.; Tejuca, S.; Vazquez, J.; Lamelas, M.L.

2002-01-01

Aim: pS2 is an estrogen regulated peptide which has been associated with a good prognosis an with a more favorable response to treatment in breast cancer patients. In ovarian tumors, the expression of pS2 was demonstrated at both mRNA and protein levels. In addition, it has been showed significant association of pS2 with mucinous differentiation or well differentiation grade of the tumors. However, it is little know about the prognostic significance of the pS2 content in ovarian carcinomas. The aims of the present work were to analyze the cytosolic pS2 content in benign and malignant ovarian tumors, its relationship with clinico-pathologic parameters, steroid receptor status, and prognostic significance. Material and Methods: We analysed the cytosolic concentrations of pS2 in 91 specimen ovarian tissues by an immunoradiometric assay (ELSA-pS2, CIS, France). The tissues were 8 normal ovaries, 43 benign tumors and 40 malignant ovarian tumors. The same ovarian tissues processed to pS2 were analyzed to Estrogen (ER) and Progesterone (PgR) Receptor status. These steroid receptors were quantified biochemically following commercial ELISA method (ABBOTT Diagnostics, Germany). The relationship between cytosolic content and clinico-pathologic factors was examined by the Mann-Whitney or Kruskall-Wallis test. Correlation between steroid receptors and pS2 content was calculated with the Spearman test. Survival curves were calculated using the Kaplan-Meier method and compared by the log-rank test. Differences were considered significant at 5% probability level. Results: pS2 could be detected in 30 cases (32.9%) with values ranged from 0.04 to 89 ng/mg prt. Only one normal ovary showed detectable levels of pS2 and there were not differences in cytosolic content between benign and malignant ovarian tumors. The pS2 levels were only associated to mucinous differentiation in both benign and malignant ovarian tumors (p=0.029 and p=0.015, respectively). Significantly higher

Reaching a few picosecond timing precision with the 16-channel digitizer and timestamper SAMPIC ASIC

Energy Technology Data Exchange (ETDEWEB)

Delagnes, E., E-mail: eric.delagnes@cea.fr [CEA/IRFU/SEDI, Saclay (France); Breton, D. [Laboratoire de L’accélérateur Linéaire from CNRS/IN2P3, Centre scientifique d’Orsay, Bâtiment 200, 91898, Orsay, Cedex (France); Grabas, H. [CEA/IRFU/SEDI, Saclay (France); Maalmi, J.; Rusquart, P. [Laboratoire de L’accélérateur Linéaire from CNRS/IN2P3, Centre scientifique d’Orsay, Bâtiment 200, 91898, Orsay, Cedex (France)

2015-07-01

SAMPIC is a Time and Waveform to Digital Converter (TWDC) multichannel chip. It integrates 16 channels each including DLL-based TDC providing a raw time associated with an ultra-fast analog memory sampling the signal used for precise timing measurements as well as other parameters of the pulse. Every channel also integrates a discriminator that can trigger it independently or participate to a more complex trigger. After triggering, the analog samples are digitized by on-chip ADCs and are sent serially to the acquisition. The paper describes the architecture of SAMPIC and reports the main performance measured on the first prototype chip with a focus on timing resolution in the range of 15 ps RMS using raw data improved to less than 5 ps RMS after a simple calibration.

The new heart of the PS is beating strongly

CERN Multimedia

Corinne Pralavorio

2011-01-01

The PS has resumed operation with a brand new electrical power system called POPS; this enormous system comprising power electronics and capacitors is crucial because if it broke down practically no particles would be able to circulate at CERN. As soon as it started, POPS passed all the tests with flying colours and is now pulsing at full power.   The new PS power system is made up of 6 containers, each with 60 tonnes of capacitors and 8 power converters. The date 11/02/11 will always be remembered with affection by the engineers in the Electrical Power Converters Group. At 11:11 in the morning (no joke), the first beams powered by the new system began to circulate in the PS. The cutely-named POPS (POwer for PS) took over from the old rotating machine that had been working since 1968. From now on it will be POPS that supplies the PS main magnets with the electrical pulses needed to accelerate the beams for the LHC and all CERN's other facilities. The system is crucial as the PS is one of the lyn...

LEADIR-PS: the path to a safe and economic SMR

Energy Technology Data Exchange (ETDEWEB)

Hart, R.S. [Nothern Nuclear Industries Inc., Cambridge, Ontario (Canada)

2014-07-01

Northern Nuclear Industries Incorporated (N{sup 2} I{sup 2}) is developing a family of Small Modular Reactors (SMRs) called LEADIR-PS, an acronym for LEAD-cooled Integral Reactor-Passively Safe. LEADIR-PS plants under development, focused on process heat applications and the energy demands of Canada, are the LEADIR-PS100 with an output of 100 MWth and LEADIR-PS300 with an output of 300 MWth. A plant consisting of six LEADIR-PS300 reactor modules serving a common turbine-generator, called the LEADIR-PS Six-Pack, is focused on serving areas with higher energy demands. LEADIR-PS integrates the inherent safety features of the Modular High Temperature Gas Reactor and molten lead coolant in an integral pool type reactor configuration. Molten lead coolant, which boils at 1750 {sup o}C,avoids the cost of a reactor pressure vessel and high pressure/high temperature reactor coolant systems, and the safety concerns regarding pressure vessel and large capacity reactor coolant system piping rupture and precludes evaporation of the coolant. Molten lead does not chemically react with air, water, or graphite. The Gen IV+ LEADIR-PS plants are inherently/passively safe. There are no active systems required for safe shutdown and decay heat removal. Safety is assured without active or stored energy power supply, without a requirement to reposition valves or other devices and operator intervention or action. The unprecedented safety achieved by LEADIR-PS reactors avoids requirements for a large exclusion radius and demanding evacuation plan requirements. LEADIR-PS, with steam conditions of 370 {sup o}C and 12 MPa (more than twice that of water cooled reactors), can serve over 85% of the world's non-transportation process heat demands and is ideally suited to serving Combined Heat and Electricity demands and industrial parks. Energy utilization of over 95% is feasible in process heat and Combined Heat and Electricity applications. The simple robust design of LEADIR-PS plants in

The OMERACT psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS): definitions of key pathologies, suggested MRI sequences, and preliminary scoring system for PsA Hands

DEFF Research Database (Denmark)

Østergaard, Mikkel; McQueen, Fiona; Wiell, Charlotte

2009-01-01

This article describes a preliminary OMERACT psoriatic arthritis magnetic resonance image scoring system (PsAMRIS) for evaluation of inflammatory and destructive changes in PsA hands, which was developed by the international OMERACT MRI in inflammatory arthritis group. MRI definitions of important...... pathologies in peripheral PsA and suggestions concerning appropriate MRI sequences for use in PsA hands are also provided....

The TORCH time-of-flight detector

Energy Technology Data Exchange (ETDEWEB)

Harnew, N., E-mail: Neville.Harnew@physics.ox.ac.uk [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N. [University College London, Department of Physics & Astronomy, Gower Street, London WC1E 6BT (United Kingdom); Castillo García, L. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Laboratory for High Energy Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Cussans, D. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Föhl, K.; Forty, R.; Frei, C. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Gao, R. [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Gys, T.; Piedigrossi, D. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Rademacker, J.; Ros Garcia, A.; Dijk, M. van [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

2016-07-11

The TORCH time-of-flight detector is being developed to provide particle identification between 2 and 10 GeV/c momentum over a flight distance of 10 m. TORCH is designed for large-area coverage, up to 30 m{sup 2}, and has a DIRC-like construction. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple Cherenkov photons produced within quartz radiator plates of 10 mm thickness. A four-year R&D programme is underway with an industrial partner (Photek, UK) to produce 53×53 mm{sup 2} Micro-Channel Plate (MCP) detectors for the TORCH application. The MCP-PMT will provide a timing accuracy of 40 ps per photon and it will have a lifetime of up to at least 5 Ccm{sup −2} of integrated anode charge by utilizing an Atomic Layer Deposition (ALD) coating. The MCP will be read out using charge division with customised electronics incorporating the NINO chipset. Laboratory results on prototype MCPs are presented. The construction of a prototype TORCH module and its simulated performance are also described.

Time resolution research in liquid scintillating detection

International Nuclear Information System (INIS)

He Hongkun; Shi Haoshan

2006-01-01

The signal processing design method is introduced into liquid scintillating detection system design. By analyzing the signal of liquid scintillating detection, improving time resolution is propitious to upgrade efficiency of detecting. The scheme of realization and satisfactory experiment data is demonstrated. Besides other types of liquid scintillating detection is the same, just using more high speed data signal processing techniques and elements. (authors)

Time-resolved ultraviolet near-field scanning optical microscope for characterizing photoluminescence lifetime of light-emitting devices.

Science.gov (United States)

Park, Kyoung-Duck; Jeong, Hyun; Kim, Yong Hwan; Yim, Sang-Youp; Lee, Hong Seok; Suh, Eun-Kyung; Jeong, Mun Seok

2013-03-01

We developed a instrument consisting of an ultraviolet (UV) near-field scanning optical microscope (NSOM) combined with time-correlated single photon counting, which allows efficient observation of temporal dynamics of near-field photoluminescence (PL) down to the sub-wavelength scale. The developed time-resolved UV NSOM system showed a spatial resolution of 110 nm and a temporal resolution of 130 ps in the optical signal. The proposed microscope system was successfully demonstrated by characterizing the near-field PL lifetime of InGaN/GaN multiple quantum wells.

Energy and expectation values of the PsH system

International Nuclear Information System (INIS)

Mitroy, J.

2006-01-01

Close to converged energies and expectation values for PsH are computed using a ground state wave function consisting of 1800 explicitly correlated gaussians. The best estimate of the Ps ∞ H energy was -0.789 196 740 hartree which is the lowest variational energy to date. The 2γ annihilation rate for Ps ∞ H was 2.471 78x10 9 s -1

TORCH—a Cherenkov based time-of-flight detector

Energy Technology Data Exchange (ETDEWEB)

Dijk, M.W.U. van, E-mail: m.vandijk@bristol.ac.uk [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Brook, N.H. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Castillo García, L. [European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23 (Switzerland); Laboratory for High Energy Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Cowie, E.N.; Cussans, D. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); D' Ambrosio, C. [European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23 (Switzerland); Fopma, J. [Denys Wilkinson Laboratory, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Forty, R.; Frei, C. [European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23 (Switzerland); Gao, R. [Denys Wilkinson Laboratory, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Gys, T. [European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23 (Switzerland); Harnew, N.; Keri, T. [Denys Wilkinson Laboratory, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Piedigrossi, D. [European Organisation for Nuclear Research (CERN), CH-1211 Geneva 23 (Switzerland)

2014-12-01

TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/c. It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate and are then focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10–15 ps per incident charged particle needs to be achieved to allow a three sigma kaon-pion separation up to 10 GeV/c momentum for the TORCH located 9.5 m from the interaction point. Given ∼30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques.

Emission properties of porphyrin compounds in new polymeric PS:CBP host

Science.gov (United States)

Jafari, Mohammad Reza; Bahrami, Bahram

2015-06-01

In this study, a device with fundamental structure of ITO/PEDOT:PSS (60 nm)/PS:CBP (70 nm)/Al (150 nm) was fabricated. The electroluminescence spectrum of device designated a red shift rather than PS:CBP photoluminescence spectra. It can be suggested that the electroplex emission occurs at PS:CBP interface. By following this step, red light-emitting devices using porphyrin compounds as a red dopant in a new host material PS:CBP with a configuration of ITO/PEDOT:PSS (60 nm)/PS:CBP:porphyrin compounds(70 nm)/Al (150 nm) have been fabricated and investigated. The electroluminescent spectra of the porphyrin compounds were red-shifted as compared with the PS:CBP blend. OLED devices based on doping 3,4PtTPP and TPPNO2 in PS:CBP showed purer red emission compared with ZnTPP and CoTPP doped devices. We believe that the electroluminescence performance of OLED devices based on porphyrin compounds depends on overlaps between the absorption of the porphyrin compounds and the emission of PS:CBP.

Spatial resolution in Micromegas detectors

CERN Document Server

Bayb, A; Giomataris, Ioanis; Zaccone, Henri; Bay, A; Perroud, Jean-Pierre; Ronga, F

2001-01-01

The performance of a telescope of Micromegas detectors has been studied in a pion beam at the CERN PS. With a gas filling of CF/sub 4 / and 20% isobutane and with a strip pitch of 100 mu m an accuracy of 14+or-3 mu m on the spatial resolution has been measured at normal incidence. A simulation demonstrates that the resolution is limited by the size of the holes of the mesh of the detector and could be reduced to 11 mu m in the same conditions with smaller holes. Even further improvement down to 8.5 mu m is feasible for the same gas with an optimized 75 mu m strip pitch. (5 refs).

Automatic Traffic Advisory and Resolution Service (ATARS) Algorithms Including Resolution-Advisory-Register Logic. Volume 2. Sections 12 through 19. Appendices,

Science.gov (United States)

1981-06-01

resolution advisory data set; ZZITIP (all. resolution advisory data sets processed); ZIP (TRADS.IEI? 12 ST292) UI!j (VMD(TRADS.INDZI3) 9T ISEP -2) 111TRIDS.FE...PROCES featurePSBPGESP2; ZL. (NIXSEPS. NAMKSPO, SMPS, SZP20); ISEPS =0; RAISMP 0; LOOP; Get the next BADS; rYITI’ (all RIDS processed); U...THIDS.PEATBITS(l) 12 ST202) In~ (TRADS..PUJTBITS(2) X2 $TRE) J (TRADS.MTITS(3) f& STU)) :MLV I (TRIDS.SIYGLE .1 SU) THlEY ISEPS = NIQIAIS!PS.PSZP2 (TRIOS

GP pain management: what are the 'Ps' and 'As' of pain management?

Science.gov (United States)

Wan, Aston

2014-08-01

Pain is one common reason for clinical encounters in primary care. The complex nature of chronic pain syndromes can make assessment and management daunting at times. This article presents an easy scheme to help general practitioners efficiently assess, manage and review/follow up patients with chronic pain. The mnemonic presented for assessment is the '4Ps' (pain, other pathology/past medical history, performance/function and psychological/psychiatric status). For management, we can also use '4Ps' (physical, psychological, pharmacological and procedural) and for review there are the '6As' (activities, analgesia, adverse effects, aberrance behaviours, affects and adequate documentation).

Design of a fusion reaction-history measurement system with high temporal resolution

International Nuclear Information System (INIS)

Peng Xiaoshi; Wang Feng; Liu Shenye; Jiang Xiaohua; Tang Qi

2010-01-01

In order to accurately measure the history of fusion reaction for experimental study of inertial confinement fusion, we advance the design of a fusion reaction-history measurement system with high temporal resolution. The diagnostic system is composed of plastic scintillator and nose cone, an optical imaging system and the system of optic streak camera. Analyzing the capability of the system indicated that the instrument measured fusion reaction history at temporal resolution as low as 55ps and 40ps correspond to 2.45MeV DD neutrons and 14.03MeV DT neutrons. The instrument is able to measure the fusion reaction history at yields 1.5 x 10 9 DD neutrons, about 4 x 10 8 DT neutrons are required for a similar quality signal. (authors)

High-Resolution Near Real-Time Drought Monitoring in South Asia

Science.gov (United States)

Aadhar, S.; Mishra, V.

2017-12-01

Drought in South Asia affect food and water security and pose challenges for millions of people. For policy-making, planning and management of water resources at the sub-basin or administrative levels, high-resolution datasets of precipitation and air temperature are required in near-real time. Here we develop a high resolution (0.05 degree) bias-corrected precipitation and temperature data that can be used to monitor near real-time drought conditions over South Asia. Moreover, the dataset can be used to monitor climatic extremes (heat waves, cold waves, dry and wet anomalies) in South Asia. A distribution mapping method was applied to correct bias in precipitation and air temperature (maximum and minimum), which performed well compared to the other bias correction method based on linear scaling. Bias-corrected precipitation and temperature data were used to estimate Standardized precipitation index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) to assess the historical and current drought conditions in South Asia. We evaluated drought severity and extent against the satellite-based Normalized Difference Vegetation Index (NDVI) anomalies and satellite-driven Drought Severity Index (DSI) at 0.05˚. We find that the bias-corrected high-resolution data can effectively capture observed drought conditions as shown by the satellite-based drought estimates. High resolution near real-time dataset can provide valuable information for decision-making at district and sub- basin levels.

Chemotherapy and quality of life in NSCLC PS 2 patients

DEFF Research Database (Denmark)

Helbekkmo, Nina; Strøm, Hans H; Sundstrøm, Stein H

2009-01-01

, fatigue, dyspnea, sleeping problems and appetite loss in comparison to the PS 0/1 group. CONCLUSIONS: PS 2 NSCLC patients seem to achieve valuable HRQOL benefits from platinum-based combination therapy. Prospective clinical studies with predefined HRQOL outcomes in PS 2 patients are needed to confirm...

CdWO{sub 4}-on-MEH-PPV:PS as a candidate for real-time dosimeters

Energy Technology Data Exchange (ETDEWEB)

Silva, M.M. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Novais, S.M.V.; Silva, E.S.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Schimitberger, T. [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil); Macedo, Z.S. [Group of Advanced Ceramic Materials, UFS, 49100-000 (Brazil); Bianchi, R.F., E-mail: bianchi@iceb.ufop.br [Laboratory of Polymers and Electronic Properties of Materials, UFOP, 35400-000 (Brazil)

2012-10-15

We report on the investigations about the modification of optical properties induced by X-rays onto film detectors of cadmium tungstate (CdWO{sub 4}), poly[2-methoxy-5(2 Prime -ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and polystyrene (PS) This device takes advantage of reduction of spectral overlap between the radioluminescence (RL) of CdWO{sub 4} and the absorption of MEH-PPV as it is exposed to radiation, forming the basis of a new dosimeter that is capable of converting the orange-red radioluminescence of PS:MEH-PPV:CdWO{sub 4} into green. We propose an explanation of the optical processes occurring in MEH-PPV:CdWO{sub 4} in terms of the radiation hardness of CdWO{sub 4} combined to the RL-induced degradation of MEH-PPV. Highlights: Black-Right-Pointing-Pointer Thin composite film dosimeters using a combination of a scintillator crystal and a light-emitting polymer. Black-Right-Pointing-Pointer A X-ray dose detector based on MEH-PPV/CdWO{sub 4} materials which are rarely seen together. Black-Right-Pointing-Pointer A new smart, disposable and easy-to-read organic-inorganic radiation detector.

Hardware solution for continuous time-resolved burst detection of single molecules in flow

Science.gov (United States)

Wahl, Michael; Erdmann, Rainer; Lauritsen, Kristian; Rahn, Hans-Juergen

1998-04-01

Time Correlated Single Photon Counting (TCSPC) is a valuable tool for Single Molecule Detection (SMD). However, existing TCSPC systems did not support continuous data collection and processing as is desirable for applications such as SMD for e.g. DNA-sequencing in a liquid flow. First attempts at using existing instrumentation in this kind of operation mode required additional routing hardware to switch between several memory banks and were not truly continuous. We have designed a hard- and software system to perform continuous real-time TCSPC based upon a modern solid state Time to Digital Converter (TDC). Short dead times of the fully digital TDC design combined with fast Field Programmable Gay Array logic permit a continuous data throughput as high as 3 Mcounts/sec. The histogramming time may be set as short as 100 microsecond(s) . Every histogram or every single fluorescence photon can be real-time tagged at 200 ns resolution in addition to recording its arrival time relative to the excitation pulse. Continuous switching between memory banks permits concurrent histogramming and data read-out. The instrument provides a time resolution of 60 ps and up to 4096 histogram channels. The overall instrument response function in combination with a low cost picosecond diode laser and an inexpensive photomultiplier tube was found to be 180 ps and well sufficient to measure sub-nanosecond fluorescence lifetimes.

Effect of PS-K on long-term survival of primary lung cancer patients treated with radiation

International Nuclear Information System (INIS)

Okazaki, Atsushi; Nakajima, Nobuaki; Hayakawa, Kazushige; Saito, Yoshihiro; Mitomo, Osamu; Niibe, Hideo

1984-01-01

The effect of PS-K on long-term survival of primary lung cancer patients irradiated over 60 Gy through 1977 to 1982 was studied. PS-K was administrated orally 3.0 g, daily or intermittently in the pattern of 2 weeks per a month on patients of positive PPD skin test. All cases irradiated over 60 Gy were 174 (Group A) containing 62 cases with PS-K (Group B) and 112 cases without PS-K (Group C). Of group B, 44 cases were administrated within a month after curative irradiation (Group B1), 7 cases were administrated on time maintaining long-term good condition after irradiation (Group B2) and 11 cases were administrated after recognition of recurrence or metastasis (Group B3). Following results were obtained. 1. Obvious prolongation of survivals was recognized in the patients with PS-K after irradiation. (1) The cumulative 5 years survival rates of Group A, B 1 and C were 11.0%, 28.8% and 4.8%, respectively. (2) The cumulative 5 years survival rates of stage I,11 were 45.7% with PS-K and 10.7% without PS-K. (3) The cumulative 5 years survival rates of 21 cases matched age, sex, stage, histological type and tumor dose with and without PS-K were 37.8% and 7.2%. (4) In Group B 2, 5 cases out of 7 cases have been alived, but in Group B 3, satisfactory long-term survivals ware not obtained. 2. The necessary conditions which obtain long-term survival with PS-K were thought to be follows. One is that the tumor is brought almost to vanish by irradiation. Another is that the condition of host is superior to that of tumor in host-tumor relationship. 3. The possibility of intermittent administration of PS-K was suggested. (author)

Direct observation of an isopolyhalomethane O-H insertion reaction with water: Picosecond time-resolved resonance Raman (ps-TR3) study of the isobromoform reaction with water to produce a CHBr2OH product

International Nuclear Information System (INIS)

Kwok, W.M.; Zhao Cunyuan; Li Yunliang; Guan Xiangguo; Phillips, David Lee

2004-01-01

Picosecond time-resolved resonance Raman (ps-TR 3 ) spectroscopy was used to obtain the first definitive spectroscopic observation of an isopolyhalomethane O-H insertion reaction with water. The ps-TR 3 spectra show that isobromoform is produced within several picoseconds after photolysis of CHBr 3 and then reacts on the hundreds of picosecond time scale with water to produce a CHBr 2 OH reaction product. Photolysis of low concentrations of bromoform in aqueous solution resulted in noticeable formation of HBr strong acid. Ab initio calculations show that isobromoform can react with water to produce a CHBr 2 (OH) O-H insertion reaction product and a HBr leaving group. This is consistent with both the ps-TR 3 experiments that observe the reaction of isobromoform with water to form a CHBr 2 (OH) product and photolysis experiments that show HBr acid formation. We briefly discuss the implications of these results for the phase dependent behavior of polyhalomethane photochemistry in the gas phase versus water solvated environments

PS Main Control Room (partial view)

CERN Multimedia

1974-01-01

Jean-Pierre Potier (turning buttons) and Bertran Frammery (telephoning) on shift. The 26 GeV Synchrotron and later also its related machines (Linacs 1,2,3; PS-Booster; LEP-Injector Linacs and Electron-Positron Accumulator; Antiproton Accumulator, Antiproton Collector, Low Energy Antiproton Ring and more recently Antiproton Decelerator) were all controlled from the PS control room situated on the Meyrin site. The SPS and LEP were controlled from a separat control centre on the Prevessin site. In 2005 all controls were transferred to the Prevessin centre.

PS overcomes two serious magnet failures

CERN Multimedia

Maximilien Brice

2003-01-01

Two magnets and a bus bar connection in the PS were found to be faulty during high-voltage tests at the end of the accelerator shutdown. A five-week repair schedule was quickly devised. A team of mechanics, technicians and engineers worked at full speed to replace the faulty magnets, succeeding in limiting the delay of the accelerators' spring start-up to two weeks. These pictures show one of the magnets (no. 19) on the PS locomotive brought back into service for the removal and replacement operations.

Beyond iPS!

Directory of Open Access Journals (Sweden)

Editorial

2012-01-01

Full Text Available It’s undoubtedly a jubilant moment for scientists and clinicians working in the stem cell arena as Prof. Gurdon and Prof. Shinya Yamanaka have been chosen for the Nobel Prize in Physiology & Medicine this year. The mystery of cell biology is something unfathomable and probably the work of this duo as well as the other scientists, who have put their hands on in- vitro de-differentiation have opened our eyes to a new window or a new paradigm in cell biology. The iPS invention has brought a lot of hope in terms of potential direct benefits to treat several diseases, which have no definite options at the moment. But, we envisage that several spin-offs could come out of this invention and one very significant spin-off finding recently witnessed is the finding by Prof. Masaharu Seno and his team of researchers at the Okayama University, Japan (Chen L, et al. 2012, PLoS ONE 7(4:e33544.doi:10.1371/journal.pone.0033544. According to Prof. Seno, mouse iPS cells (miPS when cultured in the conditioned medium derived from cancer cell lines, differentiate into cancer stem cells (CSCs. While differentiating into CSCs, they do retain the potential to develop endothelial progenitor cells. Several questions arise here: 1.Are these miPS derived CSCs really pluripotent, even if the terminal differentiation destined to specific phenotypes? 2.Shouldn’t the Cancer Stem Cells be termed as cancer progenitor cells, as till date they are considered to be producing only cancer cells but not pluripotent to yield other types of normal tissues? The spin-offs could be infinite as the process of differentiation and de-differentiation happening due to trillions of signals and pathways, most still remaining not-so-well understood. A special mention should be made to Prof. Shinya Yamanaka as he has several sterling qualities to be a role-model for budding scientists. Apart from his passion for science, which made him shift his career from orthopedics to a cell biologist, his

PS auxiliary magnet

CERN Multimedia

CERN PhotoLab

1974-01-01

Units of the PS auxiliary magnet system. The picture shows how the new dipoles, used for vertical and horizontal high-energy beam manipulation, are split for installation and removal so that it is not necessary to break the accelerator vacuum. On the right, adjacent to the sector valve and the windings of the main magnet, is an octupole of the set.

Temporal and spectral manipulations of correlated photons using a time-lens

OpenAIRE

Mittal, Sunil; Orre, Venkata Vikram; Restelli, Alessandro; Salem, Reza; Goldschmidt, Elizabeth A.; Hafezi, Mohammad

2017-01-01

A common challenge in quantum information processing with photons is the limited ability to manipulate and measure correlated states. An example is the inability to measure picosecond scale temporal correlations of a multi-photon state, given state-of-the-art detectors have a temporal resolution of about 100 ps. Here, we demonstrate temporal magnification of time-bin entangled two-photon states using a time-lens, and measure their temporal correlation function which is otherwise not accessibl...

Rejuvenation of the controls of the CERN PS/ISOLDE facility using industrial components

CERN Document Server

Allard, J.; Locci, F.; Mornacchi, G.

2001-01-01

In the context of the general consolidation of the CERN ISOLDE facility, a project has been started to upgrade the ISOLDE control system. We describe the new ISOLDE control system, emphasizing the systematic use of industrial components such as PLCs and field buses, their integration with the existing, VME based, CERN PS control system and their potential applicability to both existing and new controls problems at the CERN PS complex. We also discuss how to extend a PLC-based solution to the case where real-time response is an issue.

Timing jitter measurements at the SLC electron source

International Nuclear Information System (INIS)

Sodja, J.; Browne, M.J.; Clendenin, J.E.

1989-03-01

The SLC thermionic gun and electron source produce a beam of up to 15 /times/ 10 10 /sub e//minus/ in a single S-band bunch. A 170 keV, 2 ns FWHM pulse out of the gun is compressed by means of two subharmonic buncher cavities followed by an S-band buncher and a standard SLAC accelerating section. Ceramic gaps in the beam pipe at the output of the gun allow a measure of the beam intensity and timing. A measurement at these gaps of the timing jitter, with a resolution of <10 ps, is described. 3 refs., 5 figs

Time resolution performance studies of contemporary high speed photomultipliers

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1978-01-01

The time resolution capabilities of prototype microchannel plate and static crossed-field photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single phtoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems. 16 refs

High-resolution seismic wave propagation using local time stepping

KAUST Repository

Peter, Daniel

2017-03-13

High-resolution seismic wave simulations often require local refinements in numerical meshes to accurately capture e.g. steep topography or complex fault geometry. Together with explicit time schemes, this dramatically reduces the global time step size for ground-motion simulations due to numerical stability conditions. To alleviate this problem, local time stepping (LTS) algorithms allow an explicit time stepping scheme to adapt the time step to the element size, allowing nearoptimal time steps everywhere in the mesh. This can potentially lead to significantly faster simulation runtimes.

Caracterização viscosimétrica de nanocompósitos híbridos PS/POSS Viscometric characterization of PS/POSS hybrid nanocomposites

Directory of Open Access Journals (Sweden)

Otávio Bianchi

2012-01-01

Full Text Available Nanocompósitos híbridos de poliestireno (PS e poliedros oligoméricos silsesquioxanos (POSS com diferentes composições e graus de hibridização foram obtidos por processamento reativo no estado fundido utilizando-se peróxido de dicumila (DCP como iniciador, na presença ou não de estireno como agente de transferência de radical. Os materiais foram caracterizados viscosimetricamente por cromatografia de permeação em gel (GPC usando detecção tripla por espalhamento de luz, viscosimetria e índice de refração. As amostras PS/POSS processadas com estireno apresentaram maiores valores de massa molar ponderal média (Mw e menores valores de polidispersão (Mw/Mn, devido ao maior grau de conversão da reação de hibridização do PS-POSS (28-40% e do menor grau de degradação (cisão das cadeias do PS, quando comparadas com amostras PS/POSS processadas sem estireno nas quais o grau de conversão ficou em torno de 24-28%. Para os sistemas PS e PS/POSS em solução com THF, os parâmetros da equação de Mark-Houwink-Sakurada (MHS, α ≅ 0,7 e log K ≅ -3,5 a -3,9 e os valores dos parâmetros de interação polímero-solvente, χij ≅ 0,49, não apresentaram diferenças significativas com relação aos tamanhos moleculares. Por outro lado, essas diferenças de tamanhos moleculares foram caracterizadas por uma função cumulativa da fração mássica de cadeias em função da distância média quadrática entre pontas de cadeia (0½.Polystyrene (PS and polyhedral oligomeric silsesquioxanes (POSS hybrid nanocomposites with different compositions were obtained by reactive melt processing using dicumyl peroxide (DCP as initiator in the presence or absence of styrene as radical transfer agent. The materials were characterized by viscosimetry by means of gel permeation chromatography (GPC using triple-detector: light scattering, viscometer and refractive index. PS/POSS samples processed with styrene showed higher weight average molecular

SYSTEM OF GUARANTEED RESOLUTION OF DYNAMIC CONFLICTS OF AIRCRAFTS IN REAL TIME

Directory of Open Access Journals (Sweden)

Svitlana Pavlova

2017-03-01

Full Text Available Purpose: The present work is devoted to improving of flight safety in civil aviation by creating and implementing a new system of resolution of dynamic conflict of aircrafts. The developed system is aimed at ensuring a guaranteed level of safety when resolution of rarefied conflict situations of aircraft in real-time. Methods: The proposed system is based on a new method of conflict resolution of aircraft on the basis of the theory of invariance. Results: The development of the system of conflict resolution of aircraft in real time and the implementation of the respective algorithms such control will ensure effective prevention of dangerous approaches. Discussion: The system is implemented as single unified equipment using satellite and radar navigation systems that will ensure the positioning of aircraft in real time. Provided that the system should be installed on all aircraft and integrated on board to properly ensure its functionality and interact with navigation systems.

Digital timing: sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution

International Nuclear Information System (INIS)

Cho, Sanghee; Grazioso, Ron; Zhang Nan; Aykac, Mehmet; Schmand, Matthias

2011-01-01

The main focus of our study is to investigate how the performance of digital timing methods is affected by sampling rate, anti-aliasing and signal interpolation filters. We used the Nyquist sampling theorem to address some basic questions such as what will be the minimum sampling frequencies? How accurate will the signal interpolation be? How do we validate the timing measurements? The preferred sampling rate would be as low as possible, considering the high cost and power consumption of high-speed analog-to-digital converters. However, when the sampling rate is too low, due to the aliasing effect, some artifacts are produced in the timing resolution estimations; the shape of the timing profile is distorted and the FWHM values of the profile fluctuate as the source location changes. Anti-aliasing filters are required in this case to avoid the artifacts, but the timing is degraded as a result. When the sampling rate is marginally over the Nyquist rate, a proper signal interpolation is important. A sharp roll-off (higher order) filter is required to separate the baseband signal from its replicates to avoid the aliasing, but in return the computation will be higher. We demonstrated the analysis through a digital timing study using fast LSO scintillation crystals as used in time-of-flight PET scanners. From the study, we observed that there is no significant timing resolution degradation down to 1.3 Ghz sampling frequency, and the computation requirement for the signal interpolation is reasonably low. A so-called sliding test is proposed as a validation tool checking constant timing resolution behavior of a given timing pick-off method regardless of the source location change. Lastly, the performance comparison for several digital timing methods is also shown.

On Space-Time Resolution of Inflow Representations for Wind Turbine Loads Analysis

Directory of Open Access Journals (Sweden)

Lance Manuel

2012-06-01

Full Text Available Efficient spatial and temporal resolution of simulated inflow wind fields is important in order to represent wind turbine dynamics and derive load statistics for design. Using Fourier-based stochastic simulation of inflow turbulence, we first investigate loads for a utility-scale turbine in the neutral atmospheric boundary layer. Load statistics, spectra, and wavelet analysis representations for different space and time resolutions are compared. Next, large-eddy simulation (LES is employed with space-time resolutions, justified on the basis of the earlier stochastic simulations, to again derive turbine loads. Extreme and fatigue loads from the two approaches used in inflow field generation are compared. On the basis of simulation studies carried out for three different wind speeds in the turbine’s operating range, it is shown that inflow turbulence described using 10-meter spatial resolution and 1 Hz temporal resolution is adequate for assessing turbine loads. Such studies on the investigation of adequate filtering or resolution of inflow wind fields help to establish efficient strategies for LES and other physical or stochastic simulation needed in turbine loads studies.

A test of planar spark counters at the PEP storage ring

International Nuclear Information System (INIS)

Atwood, W.B.; Bowden, G.B.; Bonneaud, G.R.; Klem, D.E.; Ogawa, A.; Pestov, Yu.N.; Pitthan, R.; Sugahara, R.

1983-01-01

A test of planar spar counters (PSCs) at the PEP electron-positron storage ring showed the following. PSCs can be used under harsh experimental conditions without long term degradation of resolution. On-line time-of-flight resolutions were below 200 ps, coordinate resolutions better than 4 mm, both limited to these values by the resistivity of the semiconducting glass and the electronics used. The best single counter time resolution under realistic conditions at the storage ring was 76 ps. Pulse height was a good indicator of the number of particles striking a counter. Subsequent measurements using cosmis rays gave a single counter time resolution of 50 ps. (orig.)

Tablet disintegration studied by high-resolution real-time magnetic resonance imaging.

OpenAIRE

Quodbach, J.; Moussavi, A.; Tammer, R.; Frahm, J.; Kleinebudde, P.

2014-01-01

The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 x 80 m with a section thickness of only 600 m were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the i...

High resolution fast neutron spectrometry without time-of-flight

International Nuclear Information System (INIS)

Evans, A.E.; Brandenberger, J.D.

1978-01-01

Performance tests of a spectrometer tube of the type developed by Cuttler and Shalev show that the measurement of fast neutron spectra with this device can be made with an energy resolution previously obtainable only in large time-of-flight facilities. In preliminary tests, resolutions of 16.4 keV for thermal neutrons and 30.9 keV for 1-MeV neutrons were obtained. A broad-window pulse-shape discrimination (PSD) system is used to remove from pulse-height distributions most of the continua due to 3 He-recoil events, noise, and wall effect. Use of PSD improved the energy resolution to 12.9 keV for thermal neutrons and 29.2 keV for 1-MeV neutrons. The detector is a viable tool for neutron research at nominally equipped accelerator laboratories

Low cost time to digital converter in real time with +-1 ns resolution

Energy Technology Data Exchange (ETDEWEB)

Lenzi, G; Podini, P; Reverberi, R [Parma Univ. (Italy). Istituto di Fisica; Pernestaal, K [Uppsala Univ. (Sweden). Fysiska Institutionen

1977-04-15

A time to digital converter (TDC) with a time resolution of 1 ns has been designed. The deadtime is T+0.6 ..mu..s where T is the measured time. The time range can be preselected between 0.3 and 10 ..mu..s. The TDC has one START and three mutually exclusive STOP inputs which accept standard pulses (-16 mA). The time information is presented as a bit binary word, including the activated stop input address. The instrument has been successfully used in ..mu../sup +/SR (muon spin rotation) measurements and has proven itself advantageous over the more common TAC+ADC combination.

Time resolution performance studies of contemporary high speed photomultipliers

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1977-01-01

The time resolution capabilities of prototype microchannel plate and static crossed-field photomultipliers have been investigated. Measurements were made of electron transit time, rise time, time response, single photoelectron time spread and multiphotoelectron time spread for LEP HR350 proximity focused high gain curved microchannel plate and VPM-154A/1.6L static crossed-field photomultipliers. The experimental data have been compared with results obtained with conventionally designed RCS 8850 and C31024 high speed photomultipliers. Descriptions are given of both the measuring techniques and the measuring systems

Time-resolved brightness measurements by streaking

Science.gov (United States)

Torrance, Joshua S.; Speirs, Rory W.; McCulloch, Andrew J.; Scholten, Robert E.

2018-03-01

Brightness is a key figure of merit for charged particle beams, and time-resolved brightness measurements can elucidate the processes involved in beam creation and manipulation. Here we report on a simple, robust, and widely applicable method for the measurement of beam brightness with temporal resolution by streaking one-dimensional pepperpots, and demonstrate the technique to characterize electron bunches produced from a cold-atom electron source. We demonstrate brightness measurements with 145 ps temporal resolution and a minimum resolvable emittance of 40 nm rad. This technique provides an efficient method of exploring source parameters and will prove useful for examining the efficacy of techniques to counter space-charge expansion, a critical hurdle to achieving single-shot imaging of atomic scale targets.

PS-Modules over Ore Extensions and Skew Generalized Power Series Rings

Directory of Open Access Journals (Sweden)

Refaat M. Salem

2015-01-01

Full Text Available A right R-module MR is called a PS-module if its socle, SocMR, is projective. We investigate PS-modules over Ore extension and skew generalized power series extension. Let R be an associative ring with identity, MR a unitary right R-module, O=Rx;α,δ Ore extension, MxO a right O-module, S,≤ a strictly ordered additive monoid, ω:S→EndR a monoid homomorphism, A=RS,≤,ω the skew generalized power series ring, and BA=MS,≤RS,≤, ω the skew generalized power series module. Then, under some certain conditions, we prove the following: (1 If MR is a right PS-module, then MxO is a right PS-module. (2 If MR is a right PS-module, then BA is a right PS-module.

The Magnetic Recoil Spectrometer for time-resolved neutron measurements (MRSt) at the NIF

Science.gov (United States)

Parker, C. E.; Frenje, J. A.; Wink, C. W.; Gatu Johnson, M.; Lahmann, B.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Hilsabeck, T. J.; Kilkenny, J. D.; Bionta, R.; Casey, D. T.; Khater, H. Y.; Forrest, C. J.; Glebov, V. Yu.; Sorce, C.; Hares, J. D.; Siegmund, O. H. W.

2017-10-01

The next-generation Magnetic Recoil Spectrometer, called MRSt, will provide time-resolved measurements of the DT-neutron spectrum. These measurements will provide critical information about the time evolution of the fuel assembly, hot-spot formation, and nuclear burn in Inertial Confinement Fusion (ICF) implosions at the National Ignition Facility (NIF). The neutron spectrum in the energy range 12-16 MeV will be measured with high accuracy ( 5%), unprecedented energy resolution ( 100 keV) and, for the first time ever, time resolution ( 20 ps). An overview of the physics motivation, conceptual design for meeting these performance requirements, and the status of the offline tests for critical components will be presented. This work was supported in part by the U.S. DOE, LLNL, and LLE.

Proceedings of the workshop on the PS-spin collider

International Nuclear Information System (INIS)

Mori, Yoshiharu

1993-05-01

This volume is a record of the PS-Spin Collider Workshop which was held at KEK, Jan. 31-Feb.1, 1992. As a future project of the KEK 12-GeV proton synchrotron (KEK-PS), the hadron collider (PS-Collider), has been under discussion. Originally, the PSC was designed for heavy ion beam collisions with the energy range of 5-7 GeV/u. If polarized protons are accelerated in PSC, 19 x 19 GeV collisions are possible. This workshop was proposed to bring together interested experimentalists and accelerator physicists to discuss the case that could be made for polarization physics and the technical feasibility at the PS Spin Collider. More than 30 physicists participated in the workshop and very interesting and useful discussions took place. (author)

Improved H-κ Method by Harmonic Analysis on Ps and Crustal Multiples in Receiver Functions with respect to Dipping Moho and Crustal Anisotropy

Science.gov (United States)

Li, J.; Song, X.; Wang, P.; Zhu, L.

2017-12-01

The H-κ method (Zhu and Kanamori, 2000) has been widely used to estimate the crustal thickness and Vp/Vs ratio with receiver functions. However, in regions where the crustal structure is complicated, the method may produce uncertain or even unrealistic results, arising particularly from dipping Moho and/or crustal anisotropy. Here, we propose an improved H-κ method, which corrects for these effects first before stacking. The effect of dipping Moho and crustal anisotropy on Ps receiver function has been well studied, but not as much on crustal multiples (PpPs and PpSs+PsPs). Synthetic tests show that the effect of crustal anisotropy on the multiples are similar to Ps, while the effect of dipping Moho on the multiples is 5 times that on Ps (same cosine trend but 5 times in time shift). A Harmonic Analysis (HA) method for dipping/anisotropy was developed by Wang et al. (2017) for crustal Ps receiver functions to extract parameters of dipping Moho and crustal azimuthal anisotropy. In real data, the crustal multiples are much more complicated than the Ps. Therefore, we use the HA method (Wang et al., 2017), but apply separately to Ps and the multiples. It shows that although complicated, the trend of multiples can still be reasonably well represented by the HA. We then perform separate azimuthal corrections for Ps and the multiples and stack to obtain a combined receiver function. Lastly, the traditional H-κ procedure is applied to the stacked receiver function. We apply the improved H-κ method on 40 CNDSN (Chinese National Digital Seismic Network) stations distributed in a variety of geological setting across the Chinese continent. The results show apparent improvement compared to the traditional H-κ method, with clearer traces of multiples and stronger stacking energy in the grid search, as well as more reliable H-κ values.

Hybrid fs/ps CARS for Sooting and Particle-laden Flames

Energy Technology Data Exchange (ETDEWEB)

Hoffmeister, Kathryn N. Gabet; Guildenbecher, Daniel Robert; Kearney, Sean P.

2015-12-01

We report the application of ultrafast rotational coherent anti-Stokes Raman scattering (CARS) for temperature and relative oxygen concentration measurements in the plume emanating from a burning aluminized ammonium perchlorate propellant strand. Combustion of these metal-based propellants is a particularly hostile environment for laserbased diagnostics, with intense background luminosity, scattering and beam obstruction from hot metal particles that can be as large as several hundred microns in diameter. CARS spectra that were previously obtained using nanosecond pulsed lasers in an aluminumparticle- seeded flame are examined and are determined to be severely impacted by nonresonant background, presumably as a result of the plasma formed by particulateenhanced laser-induced breakdown. Introduction of fs/ps laser pulses enables CARS detection at reduced pulse energies, decreasing the likelihood of breakdown, while simultaneously providing time-gated elimination of any nonresonant background interference. Temperature probability densities and temperature/oxygen correlations were constructed from ensembles of several thousand single-laser-shot measurements from the fs/ps rotational CARS measurement volume positioned within 3 mm or less of the burning propellant surface. Preliminary results in canonical flames are presented using a hybrid fs/ps vibrational CARS system to demonstrate our progress towards acquiring vibrational CARS measurements for more accurate temperatures in the very high temperature propellant burns.

Preliminary test of 5-gap glass multi-gap resistive plate chamber for photon detection for time of flight positron emission tomography (TOF-PET) imaging

International Nuclear Information System (INIS)

Ganai, R.; Mondal, M.; Mehta, S.; Chattopadhyay, S.

2016-01-01

Multi-gap Resistive Plate Chamber (MRPC) is a type of gas detector which uses constant and uniform electric field in between several high resistive electrodes and works on the principle of gas ionisation. In MRPC a particular gas gap is divided into several parts with the help of thin high resistive electrodes. Division of the gas gap helps to improve the time resolution of the detector significantly. MRPCs with time resolution of ∼15 ps have been reported

Time resolved ion beam induced charge collection

International Nuclear Information System (INIS)

Sexton W, Frederick; Walsh S, David; Doyle L, Barney; Dodd E, Paul

2000-01-01

Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a -.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients

Time resolved ion beam induced charge collection

Energy Technology Data Exchange (ETDEWEB)

SEXTON,FREDERICK W.; WALSH,DAVID S.; DOYLE,BARNEY L.; DODD,PAUL E.

2000-04-01

Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a {minus}.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients.

Timing and position response of a block detector for fast neutron time-of-flight imaging

Energy Technology Data Exchange (ETDEWEB)

Laubach, M.A., E-mail: mlaubach@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Hayward, J.P., E-mail: jhayward@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Oak Ridge National Laboratory, 1 Bethel Valley Rd., Oak Ridge, TN 37831 (United States); Zhang, X., E-mail: xzhang39@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Cates, J.W., E-mail: jcates7@vols.utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

2014-11-01

Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of σ=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations.

Laser fusion diagnostics

International Nuclear Information System (INIS)

Coleman, L.W.

1978-01-01

The current status of the capability of laser fusion diagnostics is reviewed. Optical and infrared streak cameras provide one time resolution measurement capability of less than 10 ps, while x-ray streak cameras provide 15 ps time resolution in the range of about 1--30 keV presently. Time integrated spatial resolutions of 1 μm are provided with a variety of optical techniques. Ultraviolet holographic interferometry has measured electron densities above 10 21 cm -3 with 1 μm spatial resolution and 15 ps temporal resolution. X-ray microscopes provide 3 μm time integrated resolution and the x-ray streak pinhole camera has 6 μm spatial resolution. Development of the framing camera has thus far provided 50 μm spatial resolution with 125 ps frame duration and the third order reconstruction of zone plate images has provided 3 μm resolutions for alpha particles. Time integrated measurements of x-rays span the range shown. Finally, the new Shiva neutron spectrometer increases the energy resolution capability of that technique to 25 keV for 14-MeV neutrons. These combined capabilities provide a unique set of diagnostics for the detailed measurement of the interaction of laser light with targets and a subsequent performance of those targets

Chronic Stress Contributes to Cognitive Dysfunction and Hippocampal Metabolic Abnormalities in APP/PS1 Mice

Directory of Open Access Journals (Sweden)

Bing Han

2017-03-01

Full Text Available Background/Aims: Stress response is determined by the brain, and the brain is a sensitive target for stress. Our previous experiments have confirmed that once the stress response is beyond the tolerable limit of the brain, particularly that of the hippocampus, it will have deleterious effects on hippocampal structure and function; however, the metabolic mechanisms for this are not well understood. Methods: Here, we used morris water maze, elisa and gas chromatography-time of flight/mass spectrometry to observe the changes in cognition, neuropathology and metabolomics in the hippocampus of APP/PS1 mice and wild-type (C57 mice caused by chronic unpredictable mild stress (CUMS, we also further explored the correlation between cognition and metabolomics. Results: We found that 4 weeks of CUMS aggravated cognitive impairment and increased amyloid-β deposition in APP/PS1 mice, but did not affect C57 mice. Under non-stress conditions, compared with C57 mice, there were 8 different metabolites in APP/PS1 mice. However, following CUMS, 3 different metabolites were changed compared with untreated C57 mice. Compared to APP/PS1 mice, there were 7 different metabolites in APP/PS1+CUMS mice. Among these alterations, 3-hydroxybutyric acid, valine, serine, beta-alanine and o-phosphorylethanolamine, which are involved in sphingolipid metabolism, synthesis and degradation of ketone bodies, and amino acid metabolism. Conclusion: The results indicate that APP/PS1 mice are more vulnerable to stress than C57 mice, and the metabolic mechanisms of stress-related cognitive impairment in APP/PS1 mice are related to multiple pathways and networks, including sphingolipid metabolism, synthesis and degradation of ketone bodies, and amino acid metabolism.

A multi-channel high-resolution time recorder system

International Nuclear Information System (INIS)

Zhang Lingyun; Yang Xiaojun; Song Kezhu; Wang Yanfang

2004-01-01

This paper introduces a multi-channel and high-speed time recorder system, which was originally designed to work in the experiments of quantum cryptography research. The novelty of the system is that all the hardware logic is performed by only one FPGA. The system can achieve several desirable features, such as simplicity, high resolution and high processing speed. (authors)

Effect of refraction index and thickness of the light guide in the position-sensitive gamma-ray detector using compact PS-PMTs

International Nuclear Information System (INIS)

Inoue, K.; Saito, H.; Nagashima, Y.; Hyodo, T.; Nagai, Y.; Muramatsu, S.; Nagai, S.

2000-01-01

We constructed a position-sensitive gamma-ray detector consisting of an array of BGO scintillators, a light guide and compact PS-PMTs. The effects of refractive index and thickness of the light guide of a glass plate on the detector performance were investigated. A light guide with higher refractive index and smaller thickness is found better for a good spatial resolution.

Omega-conotoxin- and nifedipine-insensitive voltage-operated calcium channels mediate K(+)-induced release of pro-thyrotropin-releasing hormone-connecting peptides Ps4 and Ps5 from perifused rat hypothalamic slices.

Science.gov (United States)

Valentijn, K; Tranchand Bunel, D; Vaudry, H

1992-07-01

The rat thyrotropin-releasing hormone (TRH) precursor (prepro-TRH) contains five copies of the TRH progenitor sequence linked together by intervening sequences. Recently, we have shown that the connecting peptides prepro-TRH-(160-169) (Ps4) and prepro-TRH-(178-199) (Ps5) are released from rat hypothalamic neurones in response to elevated potassium concentrations, in a calcium-dependent manner. In the present study, the role of voltage-operated calcium channels in potassium-induced release of Ps4 and Ps5 was investigated, using a perifusion system for rat hypothalamic slices. The release of Ps4 and Ps5 stimulated by potassium (70 mM) was blocked by the inorganic ions Co2+ (2.6 mM) and Ni2+ (5 mM). In contrast, the stimulatory effect of KCl was insensitive to Cd2+ (100 microM). The dihydropyridine antagonist nifedipine (10 microM) had no effect on K(+)-evoked release of Ps4 and Ps5. Furthermore, the response to KCl was not affected by nifedipine (10 microM) in combination with diltiazem (1 microM), a benzothiazepine which increases the affinity of dihydropyridine antagonists for their receptor. The dihydropyridine agonist BAY K 8644, at concentrations as high as 1 mM, did not stimulate the basal secretion of Ps4 and Ps5. In addition, BAY K 8644 had no potentiating effect on K(+)-induced release of Ps4 and Ps5. The marine cone snail toxin omega-conotoxin, a blocker of both L- and N-type calcium channels had no effect on the release of Ps4 and Ps5 stimulated by potassium. Similarly, the omega-conopeptide SNX-111, a selective blocker of N-type calcium channels, did not inhibit the stimulatory effect of potassium. The release of Ps4 and Ps5 evoked by high K+ was insensitive to the non-selective calcium channel blocker verapamil (20 microM). Amiloride (1 microM), a putative blocker of T-type calcium channels, did not affect KCl-induced secretion of the two connecting peptides. Taken together, these results indicate that two connecting peptides derived from the pro-TRH, Ps

Long-term Culture of Human iPS Cell-derived Telencephalic Neuron Aggregates on Collagen Gel.

Science.gov (United States)

Oyama, Hiroshi; Takahashi, Koji; Tanaka, Yoshikazu; Takemoto, Hiroshi; Haga, Hisashi

2018-01-01

It takes several months to form the 3-dimensional morphology of the human embryonic brain. Therefore, establishing a long-term culture method for neuronal tissues derived from human induced pluripotent stem (iPS) cells is very important for studying human brain development. However, it is difficult to keep primary neurons alive for more than 3 weeks in culture. Moreover, long-term adherent culture to maintain the morphology of telencephalic neuron aggregates induced from human iPS cells is also difficult. Although collagen gel has been widely used to support long-term culture of cells, it is not clear whether human iPS cell-derived neuron aggregates can be cultured for long periods on this substrate. In the present study, we differentiated human iPS cells to telencephalic neuron aggregates and examined long-term culture of these aggregates on collagen gel. The results indicated that these aggregates could be cultured for over 3 months by adhering tightly onto collagen gel. Furthermore, telencephalic neuronal precursors within these aggregates matured over time and formed layered structures. Thus, long-term culture of telencephalic neuron aggregates derived from human iPS cells on collagen gel would be useful for studying human cerebral cortex development.Key words: Induced pluripotent stem cell, forebrain neuron, collagen gel, long-term culture.

Time-domain diagnostics in the picosecond regime

International Nuclear Information System (INIS)

Lumpkin, A.H.

1995-01-01

The measurement of bunch length and longitudinal profile for microbunches of electrons and positrons in the ps and sub-ps regime will be a critical part of validating performance of proposed facilities. Data will be presented showing single-sweep streak camera results at σ res ∼ 68 fs and projected synchroscan sweep resolution at σ ∼ 600 fs. Additionally, an rf cavity operating in a transverse magnetic mode has recently been shown to produce σ res ∼ 280 fs when used with a low-emittance beam. The potential for dual-sweep streak work with σ res < 1 ps on the fast axis is also described

Crystallographic features related to a van der Waals coupling in the layered chalcogenide FePS{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Murayama, Chisato; Okabe, Momoko; Fukuda, Koichiro [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku Nagoya 466-8555 (Japan); Urushihara, Daisuke; Asaka, Toru, E-mail: asaka.toru@nitech.ac.jp [Department of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku Nagoya 466-8555 (Japan); Frontier Research Institute for Materials Science, Nagoya Institute of Technology, Gokiso-cho, Showa-ku Nagoya 466-8555 (Japan); Isobe, Masahiko [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Yamamoto, Kazuo [Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587 (Japan); Matsushita, Yoshitaka [Research Network and Facility Services Division, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan)

2016-10-14

We investigated the crystallographic structure of FePS{sub 3} with a layered structure using transmission electron microscopy and powder X-ray diffraction. We found that FePS{sub 3} forms a rotational twin structure with the common axis along the c*-axis. The high-resolution transmission electron microscopy images revealed that the twin boundaries were positioned at the van der Waals gaps between the layers. The narrow bands of dark contrast were observed in the bright-field transmission electron microscopy images below the antiferromagnetic transition temperature, T{sub N} ≈ 120 K. Low-temperature X-ray diffraction showed a lattice distortion; the a- and b-axes shortened and lengthened, respectively, as the temperature decreased below T{sub N.} We propose that the narrow bands of dark contrast observed in the bright-field transmission electron microscopy images are caused by the directional lattice distortion with respect to each micro-twin variant in the antiferromagnetic phase.

New safety training for access to the PS complex areas

CERN Multimedia

2012-01-01

Since 10/08/2012, a new course dedicated to the specific radiological risks in the accelerators of the PS complex has been available on SIR (https://sir.cern.ch/). This course complements the general classroom-based Radiation Safety training. Successful completion of the course will be obligatory and verified by the access system as from 01/11/2012 for access to the following accelerator areas: LINAC2, BOOSTER, PS and TT2. Information and reminder e-mails will be sent to all persons currently authorized to access the accelerators of the PS complex. For questions please contact the HSE unit and in particular, the Radiation Protection Group (+41227672504 or safety-rp-ps-complex@cern.ch).

The PS booster

CERN Multimedia

CERN PhotoLab

1972-01-01

The PS booster which accelerates protons from the linac at an energy of 50 MeV to an energy of 800 MeV before injecting them into the main magnet ring of the synchrotron. The booster consists of four superposed rings. In the photograph can be seen the input beam line from the linac and the output beam lines, where beams from the four booster levels have been combined into two beams before final recombination.

Measurement and simulation of the inelastic resolution function of a time-of-flight spectrometer

International Nuclear Information System (INIS)

Roth, S.V.; Zirkel, A.; Neuhaus, J.; Petry, W.; Bossy, J.; Peters, J.; Schober, H.

2002-01-01

The deconvolution of inelastic neutron scattering data requires the knowledge of the inelastic resolution function. The inelastic resolution function of the time-of-flight spectrometer IN5/ILL has been measured by exploiting the sharp resonances of the roton and maxon excitations in superfluid 4 He for the two respective (q,ω) values. The calculated inelastic resolution function for three different instrumental setups is compared to the experimentally determined resolution function. The agreement between simulation and experimental data is excellent, allowing us in principle to extrapolate the simulations and thus to determine the resolution function in the whole accessible dynamic range of IN5 or any other time-of-flight spectrometer. (orig.)

Measurement and simulation of the inelastic resolution function of a time-of-flight spectrometer

CERN Document Server

Roth, S V; Neuhaus, J; Petry, W; Bossy, J; Peters, J; Schober, H

2002-01-01

The deconvolution of inelastic neutron scattering data requires the knowledge of the inelastic resolution function. The inelastic resolution function of the time-of-flight spectrometer IN5/ILL has been measured by exploiting the sharp resonances of the roton and maxon excitations in superfluid sup 4 He for the two respective (q,omega) values. The calculated inelastic resolution function for three different instrumental setups is compared to the experimentally determined resolution function. The agreement between simulation and experimental data is excellent, allowing us in principle to extrapolate the simulations and thus to determine the resolution function in the whole accessible dynamic range of IN5 or any other time-of-flight spectrometer. (orig.)

Development of a fast rise-time, high-voltage pulse generator

International Nuclear Information System (INIS)

Zhang Yanxia; Zhu Jie; Li Xianyou

2006-01-01

In order to test the attenuation of the system, a fast rise-time, high-voltage pulse generator is required for the fast pulse signal measurement. The paper presents the development of the generator. More emphasis is paid on the discussion of the difficulties occurring in the circuit debugging and their resolutions. The output rise-time of the generator is 700 ps, the amplitude is adjustable in the range of 0 to 500 V, the pulse-width is adjustable in the range of 4ns to 1μs. (authors)

Wide-range time-to-digital converters with a high resolution

International Nuclear Information System (INIS)

Aul'chenko, V.M.

1977-01-01

A combined time-number converter in which measurements of time intervals to within a period of clock frequency are made directly and those within a period are by a time-amplitude-code conversion is described. It allows time intervals up to 4 mcsec with a resolution of 100 psec to be measured. The differential nonlinearity of conversion is not greater than +-1.5%, and the integral error from measurements of time intervals is not greater than +-100 psec

Large strip RPCs for the LEPS2 TOF system

Energy Technology Data Exchange (ETDEWEB)

Tomida, N., E-mail: natsuki@scphys.kyoto-u.ac.jp [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Niiyama, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Ohnishi, H. [RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198 (Japan); Tran, N. [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Hsieh, C.-Y.; Chu, M.-L.; Chang, W.-C. [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Chen, J.-Y. [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 30076, Taiwan (China)

2014-12-01

High time-resolution resistive plate chambers (RPCs) with large-size readout strips are developed for the time-of-flight (TOF) detector system of the LEPS2 experiment at SPring-8. The experimental requirement is a 50-ps time resolution for a strip size larger than 100 cm{sup 2}/channel. We are able to achieve 50-ps time resolutions with 2.5×100 cm{sup 2} strips by directly connecting the amplifiers to strips. With the same time resolution, the number of front-end electronics (FEE) is also reduced by signal addition. - Highlights: • Find a way to achieve a good time resolution with a large strip RPC. • 2.5 cm narrow strips have better resolutions than 5.0 cm ones. • The 0.5 mm narrow strip interval shows flat time resolutions between strips. • FEEs directly connected to strips make the signal reflection at the strip edge small. • A time resolution of 50 ps was achieved with 2.5 cm×100 cm strips.

Test beam & time resolution analysis for UFSD and CVD diamond detectors

CERN Document Server

Scali, Stefano

2017-01-01

The ever-increasing luminosity in particle physics, aimed at seeking new phenomena, has led to the need for radiation-hard detectors with a remarkable time resolution. To reach the goal several tests and data analysis has been performed but further development is still required. During my internship I have participated to the test of new sensors. After an introduction to the theoretical framework this report describes the data taking procedure using SPS beam at the H8 site in Prevessin. The second part describes the data analysis and extrapolation of the time resolution for many boards.

Differential expression of GSK3β and pS9GSK3β in normal human tissues: can pS9GSK3β be an epithelial marker?

Science.gov (United States)

Lee, Hojung; Ro, Jae Y

2015-01-01

Glycogen synthase kinase 3β (GSK3β) and phosphorylated GSK3β at Ser9 (pS9GSK3β) are crucial in cellular proliferation and metabolism. GSK3β and pS9GSK3β are deregulated in many diseases including tumors. Data on altered expression of GSK3β and pS9GSK3β are mainly limited to tumor tissues, thus the expression of GSK3β and pS9GSK3β in normal human tissue has been largely unknown. Thus, we examined the immunohistochemical localization of GSK3β and pS9GSK3β in human fetal and adult tissues, and also compared the expression pattern of GSK3β and pS9GSK3β with that of the CK7 and CK20. We found GSK3β expression in neurons of brain, myenteric plexus in gastrointestinal tract, squamous epithelium of skin, and mammary gland. The expression of pS9GSK3β was restricted to the epithelial cells of breast and pancreaticobiliary duct, distal nephron of kidney, gastrointestinal tract, fallopian tube, epididymis, secretory cell of prostatic gland, and umbrella cell of urinary tract. The staining pattern of pS9GSK3β and CK7 was overlapped in most organs except for gastrointestinal tract where CK7 was negative and CK20 was positive. Our results show that the expression of GSK3β may be associated with differentiation of ectodermal derived tissues and pS9GSK3β with that of epithelial cells of endodermal derived tissues in human. In addition, the expression of pS9GSK3β in the selective epithelial cells may indicate its association with secretory or barrier function of specific cells and may serve as another immunohistochemical marker for epithelial cells.

Motor-generator set of the PS main supply

CERN Multimedia

Photographic Service; CERN PhotoLab

1968-01-01

Already in 1964, the PS improvement programme included a new main magnet supply with more power for the longer cycles needed for slow extraction at the full energy of 26 GeV. This motor-generator set was installed in 1967 and took up service at the beginning of 1968. Regularly serviced and fitted with modern electronic regulation, it pulses the PS to this day.

Interleaving of beam lines inside the PS tunnel

CERN Multimedia

1983-01-01

View against the direction of the proton beams. The PS ring (section 26) is on the left. The injection tunnel for LEAR leaving from here has increased the trafic in this already busy area where the two Linacs and the transfer tunnel leading to the SPS, ISR and AA join the PS ring (cf. photo 7802260, 7802261, Annual Report 1981, p. 89, fig. 12).

A transmissão psíquica geracional

Directory of Open Access Journals (Sweden)

Vinícius Oliveira dos Santos

Full Text Available O artigo seguinte refere-se a um estudo sobre como ocorre a transmissão psíquica entre as gerações e qual sua importância na constituição psíquica do sujeito. É também objetivo deste artigo explicar o que são as transmissões intergeracional e transgeracional. Para buscar respostas para essas questões, fez-se uma pesquisa bibliográfica sobre a transmissão psíquica, pelo viés psicanalítico, principalmente a partir da teoria lacaniana e com conceitos oriundos da linguística saussuriana. Será a partir de uma determinada ordem simbólica, constituída pela linguagem que precede o sujeito, nomeado por Lacan como o Outro, que a transmissão psíquica entre gerações ganhará o seu caráter unívoco, sempre se tendo em mente a importância fundamental do recalcamento e de seus efeitos, bem como do retorno do recalcado nas diferentes gerações. A transmissão psíquica é necessária e concomitante à constituição do sujeito, e ocorre através da linguagem, dos significantes que irão determinar uma ordem simbólica para o ser que nasce através dos diferentes discursos que perpassam as gerações nas figuras dos pais desse novo ser. Essa ordem simbólica continuará a se fazer presente nesse novo sujeito pelo restante de sua existência. Este artigo busca dar nova luz ao aspecto da transmissão psíquica transgeracional, diferenciando-se da recalque s abordagens psicanalíticas contemporâneas por ser uma leitura lacaniana. Serão usados dois exemplos: um de como a transmissão aparece na cultura, outro, na subjetividade do sujeito através da arte.

TOFPET 2: A high-performance circuit for PET time-of-flight

Energy Technology Data Exchange (ETDEWEB)

Di Francesco, Agostino, E-mail: agodifra@lip.pt [LIP, Lisbon (Portugal); Bugalho, Ricardo [LIP, Lisbon (Portugal); PETsys Electronics, Oeiras (Portugal); Oliveira, Luis [CTS-UNINOVA, DEE FCT-UNL, Caparica (Portugal); Rivetti, Angelo [INFN - sez. Torino (Italy); Rolo, Manuel [LIP, Lisbon (Portugal); INFN - sez. Torino (Italy); Silva, Jose C.; Varela, Joao [LIP, Lisbon (Portugal); PETsys Electronics, Oeiras (Portugal)

2016-07-11

We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with (320 pF) capacitance the circuit has 24 (30) dB SNR, 75 (39) ps r.m.s. resolution, and 4 (8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

Gamma-induced Positron Spectroscopy (GiPS) at a superconducting electron linear accelerator

International Nuclear Information System (INIS)

Butterling, Maik; Anwand, Wolfgang; Cowan, Thomas E.; Hartmann, Andreas; Jungmann, Marco; Krause-Rehberg, Reinhard; Krille, Arnold; Wagner, Andreas

2011-01-01

A new and unique setup for Positron Annihilation Spectroscopy has been established and optimized at the superconducting linear electron accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf (Germany). The intense, pulsed (26 MHz) photon source (bremsstrahlung with energies up to 16 MeV) is used to generate positrons by means of pair production throughout the entire sample volume. Due to the very short gamma bunches (< 5 ps temporal length), the facility for Gamma-induced Positron Spectroscopy (GiPS) is suitable for positron lifetime spectroscopy using the accelerator's radiofrequency as time reference. Positron lifetime and Doppler broadening Spectroscopy are employed by a coincident measurement (Age-Momentum Correlation) of the time-of-arrival and energy of the annihilation photons which in turn significantly reduces the background of scattered photons resulting in spectra with high signal to background ratios. Simulations of the setup using the GEANT4 framework have been performed to yield optimum positron generation rates for various sample materials and improved background conditions.

Gamma-induced Positron Spectroscopy (GiPS) at a superconducting electron linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Butterling, Maik, E-mail: maik.butterling@googlemail.com [Martin-Luther University, Dept. of Physics, 06099 Halle (Germany); Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Anwand, Wolfgang; Cowan, Thomas E.; Hartmann, Andreas [Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Jungmann, Marco; Krause-Rehberg, Reinhard [Martin-Luther University, Dept. of Physics, 06099 Halle (Germany); Krille, Arnold; Wagner, Andreas [Institute of Radiation Physics, Helmholtz-Zentrum, Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

2011-11-15

A new and unique setup for Positron Annihilation Spectroscopy has been established and optimized at the superconducting linear electron accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf (Germany). The intense, pulsed (26 MHz) photon source (bremsstrahlung with energies up to 16 MeV) is used to generate positrons by means of pair production throughout the entire sample volume. Due to the very short gamma bunches (< 5 ps temporal length), the facility for Gamma-induced Positron Spectroscopy (GiPS) is suitable for positron lifetime spectroscopy using the accelerator's radiofrequency as time reference. Positron lifetime and Doppler broadening Spectroscopy are employed by a coincident measurement (Age-Momentum Correlation) of the time-of-arrival and energy of the annihilation photons which in turn significantly reduces the background of scattered photons resulting in spectra with high signal to background ratios. Simulations of the setup using the GEANT4 framework have been performed to yield optimum positron generation rates for various sample materials and improved background conditions.

Optical-fiber interferometer for velocity measurements with picosecond resolution

International Nuclear Information System (INIS)

Weng Jidong; Tan Hua; Wang Xiang; Ma Yun; Hu Shaolou; Wang Xiaosong

2006-01-01

The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors

The PS Booster, PS and SPS Magnets for the next 25 years

CERN Document Server

Tommasini, D

2010-01-01

This note provides information and analysis on the present status of the magnets installed in the CERN Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS) and the Super Proton Synchrotron (SPS) in view of their possible operation for the next 25 years. The note does not cover the magnets installed in the transfer lines, neither it covers the fast injection/extraction magnets (septa and kickers).

Neutron Time-Of-Flight (n_TOF) experiment

CERN Multimedia

Brugger, M; Kaeppeler, F K; Jericha, E; Cortes rossell, G P; Riego perez, A; Baccomi, R; Laurent, B G; Griesmayer, E; Leeb, H; Dressler, M; Cano ott, D; Variale, V; Ventura, A; Carrillo de albornoz trillo, A; Andrzejewski, J J; Pavlik, A F; Kadi, Y; Zanni vlastou, R; Krticka, M; Kokkoris, M; Praena rodriguez, A J; Cortes giraldo, M A; Perkowski, J; Losito, R; Audouin, L; Weiss, C; Tagliente, G; Wallner, A; Woods, P J; Mengoni, A; Guerrero sanchez, C G; Tain enriquez, J L; Vlachoudis, V; Calviani, M; Junghans, A R; Reifarth, R; Mendoza cembranos, E; Quesada molina, J M; Babiano suarez, V; Schumann, M D; Tsinganis, A; Rauscher, T; Calvino tavares, F; Mingrone, F; Gonzalez romero, E M; Colonna, N; Negret, A L; Chiaveri, E; Milazzo, P M; De almeida carrapico, C A; Castelluccio, D M

The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.

Probability-of-Superiority SEM (PS-SEM—Detecting Probability-Based Multivariate Relationships in Behavioral Research

Directory of Open Access Journals (Sweden)

Johnson Ching-Hong Li

2018-06-01

Full Text Available In behavioral research, exploring bivariate relationships between variables X and Y based on the concept of probability-of-superiority (PS has received increasing attention. Unlike the conventional, linear-based bivariate relationship (e.g., Pearson's correlation, PS defines that X and Y can be related based on their likelihood—e.g., a student who is above mean in SAT has 63% likelihood of achieving an above-mean college GPA. Despite its increasing attention, the concept of PS is restricted to a simple bivariate scenario (X-Y pair, which hinders the development and application of PS in popular multivariate modeling such as structural equation modeling (SEM. Therefore, this study addresses an empirical-based simulation study that explores the potential of detecting PS-based relationship in SEM, called PS-SEM. The simulation results showed that the proposed PS-SEM method can detect and identify PS-based when data follow PS-based relationships, thereby providing a useful method for researchers to explore PS-based SEM in their studies. Conclusions, implications, and future directions based on the findings are also discussed.

Intron-exon organization of the active human protein S gene PS. alpha. and its pseudogene PS. beta. : Duplication and silencing during primate evolution

Energy Technology Data Exchange (ETDEWEB)

Ploos van Amstel, H.; Reitsma, P.H.; van der Logt, C.P.; Bertina, R.M. (University Hospital, Leiden (Netherlands))

1990-08-28

The human protein S locus on chromosome 3 consists of two protein S genes, PS{alpha} and PS{beta}. Here the authors report the cloning and characterization of both genes. Fifteen exons of the PS{alpha} gene were identified that together code for protein S mRNA as derived from the reported protein S cDNAs. Analysis by primer extension of liver protein S mRNA, however, reveals the presence of two mRNA forms that differ in the length of their 5{prime}-noncoding region. Both transcripts contain a 5{prime}-noncoding region longer than found in the protein S cDNAs. The two products may arise from alternative splicing of an additional intron in this region or from the usage of two start sites for transcription. The intron-exon organization of the PS{alpha} gene fully supports the hypothesis that the protein S gene is the product of an evolutional assembling process in which gene modules coding for structural/functional protein units also found in other coagulation proteins have been put upstream of the ancestral gene of a steroid hormone binding protein. The PS{beta} gene is identified as a pseudogene. It contains a large variety of detrimental aberrations, viz., the absence of exon I, a splice site mutation, three stop codons, and a frame shift mutation. Overall the two genes PS{alpha} and PS{beta} show between their exonic sequences 96.5% homology. Southern analysis of primate DNA showed that the duplication of the ancestral protein S gene has occurred after the branching of the orangutan from the African apes. A nonsense mutation that is present in the pseudogene of man also could be identified in one of the two protein S genes of both chimpanzee and gorilla. This implicates that silencing of one of the two protein S genes must have taken place before the divergence of the three African apes.

A Kalman Filter-Based Method to Generate Continuous Time Series of Medium-Resolution NDVI Images

Directory of Open Access Journals (Sweden)

Fernando Sedano

2014-12-01

Full Text Available A data assimilation method to produce complete temporal sequences of synthetic medium-resolution images is presented. The method implements a Kalman filter recursive algorithm that integrates medium and moderate resolution imagery. To demonstrate the approach, time series of 30-m spatial resolution NDVI images at 16-day time steps were generated using Landsat NDVI images and MODIS NDVI products at four sites with different ecosystems and land cover-land use dynamics. The results show that the time series of synthetic NDVI images captured seasonal land surface dynamics and maintained the spatial structure of the landscape at higher spatial resolution. The time series of synthetic medium-resolution NDVI images were validated within a Monte Carlo simulation framework. Normalized residuals decreased as the number of available observations increased, ranging from 0.2 to below 0.1. Residuals were also significantly lower for time series of synthetic NDVI images generated at combined recursion (smoothing than individually at forward and backward recursions (filtering. Conversely, the uncertainties of the synthetic images also decreased when the number of available observations increased and combined recursions were implemented.

Real-time haptic cutting of high-resolution soft tissues.

Science.gov (United States)

Wu, Jun; Westermann, Rüdiger; Dick, Christian

2014-01-01

We present our systematic efforts in advancing the computational performance of physically accurate soft tissue cutting simulation, which is at the core of surgery simulators in general. We demonstrate a real-time performance of 15 simulation frames per second for haptic soft tissue cutting of a deformable body at an effective resolution of 170,000 finite elements. This is achieved by the following innovative components: (1) a linked octree discretization of the deformable body, which allows for fast and robust topological modifications of the simulation domain, (2) a composite finite element formulation, which thoroughly reduces the number of simulation degrees of freedom and thus enables to carefully balance simulation performance and accuracy, (3) a highly efficient geometric multigrid solver for solving the linear systems of equations arising from implicit time integration, (4) an efficient collision detection algorithm that effectively exploits the composition structure, and (5) a stable haptic rendering algorithm for computing the feedback forces. Considering that our method increases the finite element resolution for physically accurate real-time soft tissue cutting simulation by an order of magnitude, our technique has a high potential to significantly advance the realism of surgery simulators.

Evaluation of Recycling Polystyrene (PS) from a Microbiology Product

OpenAIRE

Eklöf, Jonas

2014-01-01

Detta är ett beställningsarbete av Plastone Oy och i det undersöks möjligheterna vad man kan göra genom återvinning med avfallsmaterialet som uppstår då man tillverkar en mikrobiologisk produkt i deras plastfabrik. Produkten tillverkas genom formsprutning och materialet som används är polystyren (PS). Ur litteraturstudien fann man varierande möjligheter på hur man kan återvinna PS på bästa sätt, men ingen lösning som har varit effektiv i praktiken. Det framgick också att återvunnet PS inte är...

Process equipment data organisation in CERN PS controls

International Nuclear Information System (INIS)

Casalegno, L.; Cuperus, J.; Sicard, C.H.

1990-01-01

The CERN PS control system has a widely distributed architecture, mainly for fast response in a real-time environment. The organisation of the data for equipment access must be compatible with this architecture and give efficient program access to the data. Moreover, it must also offer managerial features such as data integrity, easy backup and restoration, adaptibility to changes in data structure, initialisation, data-entry facilities and automatic documentation. This paper shows how one can take advantage of a commercial data-base management system with its associated tools, adding to it some object-oriented programming concepts to meet the objectives of a manageable distributed data organisation having good run-time performance features and using a reasonable manpower investment. (orig.)

Motor-Generator powering the PS (Proton Synchrotron) main magnets

CERN Multimedia

1983-01-01

This motor-generator,30 MW peak, 1500 r.p.m.,pulsed power supply for the PS main magnet replaced in 1968 the initial 3000 r.p.m. motor-generator-flywheel set which had served from the PS start-up in 1959 until end 1967. See also photo 8302337 and its abstract.

The surface properties of PS/PMMA blends nanostructured polymeric layers

International Nuclear Information System (INIS)

Prosycevas, I.; Tamulevicius, S.; Guobiene, A.

2004-01-01

Solvent cast thin films of blends polystyrene (PS) and poly (methylmethacrylate) (PMMA) with nominal compositions ranging from 25/75 wt.%/v% (w/v) up to 75/25 w/v PS/PMMA with toluene as the mutual solvent on crystalline Si (100) and silica substrates has been studied. Films of PS and PMMA blends have been examined by atomic force microscopy (AFM) and ellipsometry. The blend films with less than 50% PMMA bulk concentration generally exhibit pitted surfaces; the pit size varies with film thickness and bulk composition. When the PMMA bulk concentration is greater than 50%, the film surface can be described as island-like phase-separated structure. The surface segregation and morphology are explained in terms of solubility of the two polymers in the solvent and rewetting of PMMA relative to PS

Tablet disintegration studied by high-resolution real-time magnetic resonance imaging.

Science.gov (United States)

Quodbach, Julian; Moussavi, Amir; Tammer, Roland; Frahm, Jens; Kleinebudde, Peter

2014-01-01

The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 × 80 µm with a section thickness of only 600 µm were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the impact of disintegrant concentration were examined. Crospovidone seems to be the only disintegrant acting by a shape memory effect, whereas the others mainly swell. A higher relative density of tablets containing croscarmellose sodium leads to a more even distribution of water within the tablet matrix but hardly impacts the disintegration kinetics. Increasing the polacrilin potassium disintegrant concentration leads to a quicker and more thorough disintegration process. Real-time MRI emerges as valuable tool to visualize and investigate the process of tablet disintegration.

Mass test of AdvanSiD model ASD-NUV3S-P SiliconPMs for the Pixel Timing Counter of the MEG II experiment

Science.gov (United States)

Rossella, M.; Bariani, S.; Barnaba, O.; Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Nardò, R.; Prata, M. C.; Romano, E.; Scagliotti, C.; Simonetta, M.; Vercellati, F.

2017-02-01

The MEG II Timing Counter will measure the positron time of arrival with a resolution of 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They must be characterized, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximize the pixel resolution. To do this an automatic test system that can measure sequentially the parameters of 32 devices has been developed.

CoPs Facing Rationalization: The Politics of Community Reproduction

Science.gov (United States)

Kilskar, Stine Skaufel; Ingvaldsen, Jonas A.; Valle, Nina

2018-01-01

Purpose: This paper aims to explore the relationship between the contemporary forms of manufacturing rationalization and the reproduction of communities of practice (CoPs) centred on tasks and craft. Building on critical literature highlighting the tensions between CoPs and rationalization, this paper aims to develop a nuanced account of how CoPs…

Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

Energy Technology Data Exchange (ETDEWEB)

Wang, Ji; Mawet, Dimitri [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 E. California Boulevard, Pasadena, CA 91106 (United States); Prato, Lisa, E-mail: ji.wang@caltech.edu [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)

2017-03-20

Many brown dwarfs (BDs) exhibit photometric variability at levels from tenths to tens of percents. The photometric variability is related to magnetic activity or patchy cloud coverage, characteristic of BDs near the L–T transition. Time-resolved spectral monitoring of BDs provides diagnostics of cloud distribution and condensate properties. However, current time-resolved spectral studies of BDs are limited to low spectral resolution ( R ∼ 100) with the exception of the study of Luhman 16 AB at a resolution of 100,000 using the VLT+CRIRES. This work yielded the first map of BD surface inhomogeneity, highlighting the importance and unique contribution of high spectral resolution observations. Here, we report on the time-resolved high spectral resolution observations of a nearby BD binary, 2MASSW J0746425+200032AB. We find no coherent spectral variability that is modulated with rotation. Based on simulations, we conclude that the coverage of a single spot on 2MASSW J0746425+200032AB is smaller than 1% or 6.25% if spot contrast is 50% or 80% of its surrounding flux, respectively. Future high spectral resolution observations aided by adaptive optics systems can put tighter constraints on the spectral variability of 2MASSW J0746425+200032AB and other nearby BDs.

Application of large area SiPMs for the readout of a plastic scintillator based timing detector

Science.gov (United States)

Betancourt, C.; Blondel, A.; Brundler, R.; Dätwyler, A.; Favre, Y.; Gascon, D.; Gomez, S.; Korzenev, A.; Mermod, P.; Noah, E.; Serra, N.; Sgalaberna, D.; Storaci, B.

2017-11-01

In this study an array of eight 6 mm × 6 mm area SiPMs was coupled to the end of a long plastic scintillator counter which was exposed to a 2.5 GeV/c muon beam at the CERN PS. Timing characteristics of bars with dimensions 150 cm × 6 cm × 1 cm and 120 cm × 11 cm × 2.5 cm have been studied. An 8-channel SiPM anode readout ASIC (MUSIC R1) based on a novel low input impedance current conveyor has been used to read out and amplify SiPMs independently and sum the signals at the end. Prospects for applications in large-scale particle physics detectors with timing resolution below 100 ps are provided in light of the results.

Antiphosphatidylserine/prothrombin antibodies (aPS/PT) as potential markers of antiphospholipid syndrome.

Science.gov (United States)

Vlagea, Alexandru; Gil, Antonio; Cuesta, Maria V; Arribas, Florencia; Diez, Jesús; Lavilla, Paz; Pascual-Salcedo, Dora

2013-06-01

The antiphospholipid antibodies present in antiphospholipid syndrome (APS) are directed at a number of phospholipid-binding proteins: β2 glycoprotein I (β2GPI), prothrombin, and so on. Antibodies directed at β2GPI are accepted as a classification criterion for APS, while the presence of antiprothrombin antibodies is not. In the present article, we investigated the possible role of antiphosphatidylserine/prothrombin antibodies (aPS/PT) as marker of APS on a cohort of 295 individuals with APS (95 primary APS and 45 secondary APS) and APS-related diseases. We found aPS/PT to be highly associated with venous thrombosis (immunoglobulin G [IgG] aPS/PT odds ratio [OR], 7.44; 95% confidence interval [CI], 3.97-13.92 and IgM aPS/PT OR, 2.54; 95% CI, 1.35-4.77) and obstetric abnormalities (IgG aPS/PT OR, 2.37; 95% CI, 1.04-5.43), but not with arterial thrombosis. A very high degree of concordance between the concentration of aPS/PT and lupus anticoagulant activity was demonstrated. Therefore, we support the inclusion of aPS/PT determination as second-level assay to confirm APS classification.

Isoporous PS-b-PEO ultrafiltration membranes via self-assembly and water-induced phase separation

KAUST Repository

Karunakaran, Madhavan

2014-03-01

A simple and efficient approach towards the fabrication of a skinned membrane with highly ordered pores in the nanometer range is presented here. We successfully combined the self-assembly of PS-b-PEO block copolymer and water induced phase separation for the preparation of isoporous PS-b-PEO block copolymer membranes. We produced for the first time asymmetric isoporous PS-b-PEO membranes with a 100nm thin isoporous separating layer using water at room temperature as coagulant. This was possible by careful selection of the block lengths and the solvent system. FESEM, AFM and TEM measurements were employed to characterize the nanopores of membranes. The pure water fluxes were measured and the flux of membrane was exceptionally high (around 800Lm-2h-1bar-1). Protein rejection measurements were carried out for this membrane and the membrane had a retention of about 67% of BSA and 99% of γ-globulin. © 2013 Elsevier B.V.

Enhanced personal protection system for the PS

CERN Multimedia

Caroline Duc

2013-01-01

During the first long shutdown (LS1) a new safety system will be installed in the primary beam areas of the PS complex in order to bring the standard of personnel radiation protection at the PS into line with that of the LHC.   Pierre Ninin, deputy group leader of GS-ASE and responsible for the installation of the new PS complex safety system, in front of a new access control system. The LHC access control systems are state-of-the-art, whereas those of the injection chain accelerators were running the risk of becoming obsolete. For the past two years a project to upgrade the access and safety systems of the first links in the LHC accelerator chain has been underway to bring them into compliance with nuclear safety standards. These systems provide the personnel with automatic protection by limiting access to hazardous areas and by ensuring that nobody is present in the areas when the accelerator is in operation. By the end of 2013, the project teams will ha...

Simulations of the temporal and spatial resolution for a compact time-resolved electron diffractometer

Science.gov (United States)

Robinson, Matthew S.; Lane, Paul D.; Wann, Derek A.

2016-02-01

A novel compact electron gun for use in time-resolved gas electron diffraction experiments has recently been designed and commissioned. In this paper we present and discuss the extensive simulations that were performed to underpin the design in terms of the spatial and temporal qualities of the pulsed electron beam created by the ionisation of a gold photocathode using a femtosecond laser. The response of the electron pulses to a solenoid lens used to focus the electron beam has also been studied. The simulated results show that focussing the electron beam affects the overall spatial and temporal resolution of the experiment in a variety of ways, and that factors that improve the resolution of one parameter can often have a negative effect on the other. A balance must, therefore, be achieved between spatial and temporal resolution. The optimal experimental time resolution for the apparatus is predicted to be 416 fs for studies of gas-phase species, while the predicted spatial resolution of better than 2 nm-1 compares well with traditional time-averaged electron diffraction set-ups.

High-Resolution Esophageal Manometry: A Time Motion Study

Directory of Open Access Journals (Sweden)

Daniel C Sadowski

2008-01-01

Full Text Available INTRODUCTION: High-resolution manometry (HRM of the esophagus is a new technique that provides a more precise assessment of esophageal motility than conventional techniques. Because HRM measures pressure events along the entire length of the esophagus simultaneously, clinical procedure time should be shorter because less catheter manipulation is required. According to manufacturer advertising, the new HRM system is more accurate and up to 50% faster than conventional methods.

Advanced Photon Counting Imaging Detectors with 100ps Timing for Astronomical and Space Sensing Applications

Science.gov (United States)

Siegmund, O.; Vallerga, J.; Welsh, B.; Rabin, M.; Bloch, J.

In recent years EAG has implemented a variety of high-resolution, large format, photon-counting MCP detectors in space instrumentation for satellite FUSE, GALEX, IMAGE, SOHO, HST-COS, rocket, and shuttle payloads. Our scheme of choice has been delay line readouts encoding photon event position centroids, by determination of the difference in arrival time of the event charge at the two ends of a distributed resistive-capacitive (RC) delay line. Our most commonly used delay line configuration is the cross delay line (XDL). In its simplest form the delay-line encoding electronics consists of a fast amplifier for each end of the delay line, followed by time-to-digital converters (TDC's). We have achieved resolutions of Pulsar with a telescope as small as 1m. Although microchannel plate delay line detectors meet many of the imaging and timing demands of various applications, they have limitations. The relatively high gain (107) reduces lifetime and local counting rate, and the fixed delay (10's of ns) makes multiple simultaneous event recording problematic. To overcome these limitations we have begun development of cross strip readout anodes for microchannel plate detectors. The cross strip (XS) anode is a coarse (~0.5 mm) multi-layer metal and ceramic pattern of crossed fingers on an alumina substrate. The charge cloud is matched to the anode period so that it is collected on several neighboring fingers to ensure an accurate event charge centroid can be determined. Each finger of the anode is connected to a low noise charge sensitive amplifier and followed by subsequent A/D conversion of individual strip charge values and a hardware centroid determination of better than 1/100 of a strip are possible. Recently we have commissioned a full 32 x 32 mm XS open face laboratory detector and demonstrated excellent resolution (Los Alamos National Laboratory, NASA and NSF we are developing high rate (>107 Hz) XS encoding electronics that will encode temporally simultaneous

A motional Stark effect diagnostic analysis routine for improved resolution of iota in the core of the large helical device.

Science.gov (United States)

Dobbins, T J; Ida, K; Suzuki, C; Yoshinuma, M; Kobayashi, T; Suzuki, Y; Yoshida, M

2017-09-01

A new Motional Stark Effect (MSE) analysis routine has been developed for improved spatial resolution in the core of the Large Helical Device (LHD). The routine was developed to reduce the dependency of the analysis on the Pfirsch-Schlüter (PS) current in the core. The technique used the change in the polarization angle as a function of flux in order to find the value of diota/dflux at each measurement location. By integrating inwards from the edge, the iota profile can be recovered from this method. This reduces the results' dependency on the PS current because the effect of the PS current on the MSE measurement is almost constant as a function of flux in the core; therefore, the uncertainty in the PS current has a minimal effect on the calculation of the iota profile. In addition, the VMEC database was remapped from flux into r/a space by interpolating in mode space in order to improve the database core resolution. These changes resulted in a much smoother iota profile, conforming more to the physics expectations of standard discharge scenarios in the core of the LHD.

Beyond the Point Ps Approximation

OpenAIRE

Stepanov, Sergey V.; Zvezhinskiy, Dmitry S.; Byakov, Vsevolod M.

2012-01-01

In application to positron annihilation spectroscopy, Ps atom is considered not as a point particle, but as a finite size e+ e- pair localized in a bubble-state in a medium. Variation of the internal Coulombic e+ -e- attraction vs. the bubble radius is estimated.

Development of a LaBr3(Ce Fast-timing Array for FAIR

Directory of Open Access Journals (Sweden)

Roberts O.J.

2013-12-01

Full Text Available A γ-ray spectrometer with fast-timing capabilities, constructed of LaBr3(Ce:5% detectors, is under development for use at the future Facility for Anti-proton and Ion Research (FAIR. The physics aims of this device are to measure the half-lives of excited states in the region of ~50 ps to several ns, in exotic nuclei. Monte-Carlo simulations using the GEANT4 software package have determined the final design of this fast-timing array by calculating the full-energy peak efficiencies of several different detector geometries. The results of the simulated efficiencies for each configuration were used to calculate the timing precision. Consequently, an array of thirty six, ø3.8×5.1 cm cylindrical crystals was found to be the optimum configuration. The detectors were purchased and subsequently characterised, with each detector found to have intrinsic energy and timing resolutions of ~ 2.8 % (FWHM and ~ 210 ps (FWHM for the 1173 and 1332 keV decays from 60Co.

Non-viral generation of marmoset monkey iPS cells by a six-factor-in-one-vector approach.

Science.gov (United States)

Debowski, Katharina; Warthemann, Rita; Lentes, Jana; Salinas-Riester, Gabriela; Dressel, Ralf; Langenstroth, Daniel; Gromoll, Jörg; Sasaki, Erika; Behr, Rüdiger

2015-01-01

Groundbreaking studies showed that differentiated somatic cells of mouse and human origin could be reverted to a stable pluripotent state by the ectopic expression of only four proteins. The resulting pluripotent cells, called induced pluripotent stem (iPS) cells, could be an alternative to embryonic stem cells, which are under continuous ethical debate. Hence, iPS cell-derived functional cells such as neurons may become the key for an effective treatment of currently incurable degenerative diseases. However, besides the requirement of efficacy testing of the therapy also its long-term safety needs to be carefully evaluated in settings mirroring the clinical situation in an optimal way. In this context, we chose the long-lived common marmoset monkey (Callithrix jacchus) as a non-human primate species to generate iPS cells. The marmoset monkey is frequently used in biomedical research and is gaining more and more preclinical relevance due to the increasing number of disease models. Here, we describe, to our knowledge, the first-time generation of marmoset monkey iPS cells from postnatal skin fibroblasts by non-viral means. We used the transposon-based, fully reversible piggyback system. We cloned the marmoset monkey reprogramming factors and established robust and reproducible reprogramming protocols with a six-factor-in-one-construct approach. We generated six individual iPS cell lines and characterized them in comparison with marmoset monkey embryonic stem cells. The generated iPS cells are morphologically indistinguishable from marmoset ES cells. The iPS cells are fully reprogrammed as demonstrated by differentiation assays, pluripotency marker expression and transcriptome analysis. They are stable for numerous passages (more than 80) and exhibit euploidy. In summary, we have established efficient non-viral reprogramming protocols for the derivation of stable marmoset monkey iPS cells, which can be used to develop and test cell replacement therapies in

Non-viral generation of marmoset monkey iPS cells by a six-factor-in-one-vector approach.