Characterisation of Geiger-mode avalanche photodiodes for medical imaging applications

International Nuclear Information System (INIS)

Britvitch, I.; Johnson, I.; Renker, D.; Stoykov, A.; Lorenz, E.

2007-01-01

Recently developed multipixel Geiger-mode avalanche photodiodes (G-APDs) are very promising candidates for the detection of light in medical imaging instruments (e.g. positron emission tomography) as well as in high-energy physics experiments and astrophysical applications. G-APDs are especially well suited for morpho-functional imaging (multimodality PET/CT, SPECT/CT, PET/MRI, SPECT/MRI). G-APDs have many advantages compared to conventional photosensors such as photomultiplier tubes because of their compact size, low-power consumption, high quantum efficiency and insensitivity to magnetic fields. Compared to avalanche photodiodes and PIN diodes, they are advantageous because of their high gain, reduced sensitivity to pick up and the so-called nuclear counter effect and lower noise. We present measurements of the basic G-APD characteristics: photon detection efficiency, gain, inter-cell crosstalk, dynamic range, recovery time and dark count rate

Ultrafast photon number resolving detector with a temperature stabilized si multi pixel photon counter

International Nuclear Information System (INIS)

Song, Minsoo; Hong, Eugene; Won, Eunil; Yoon, Tai Hyun

2008-01-01

Quantum information science has been rapidly progressed and matured and matured thanks to the recent developments of the single photon detection technologies. Single photon detectors such as a Si avalanche photo diode(APD)in the infrared, an InGaAs/InP APD in the telecommunication band, and a super conducting transient edge sensor(TES)in the broad region of the spectrum have been widely used. Single photon detectors, however, operating at the ultraviolet to visible (370nm∼800nm)regions has not been actively investigated partly due to the lack of single photon and/or entangled photon sources and the lack of solid state single photon detectors. In this paper, we investigate the single photon detection characteristics of a Si multi pixel photon counter(MPPC), which has a high spectral responsivity between 300nm to 800nm, as a photon number resolving solid state detector. Figure 1 shows the schematic diagram of the single photon detection set up at 399nm by using a temperature stabilized Si MPPC. The output beam of the laser being properly attenuated is directed to the MPPC module, at which fixed number of photo electrons corresponding to incident individual photon are generated at Geiger mode of the Si APD pixels. The detected photo current is converted into a digital signal by using a fast analog to digital converter and a digital oscilloscope stores the time sequence of the photo currents. Figure 2 shows the accumulated charges collected by MPPC at∼10.deg.C showing a clear single photon and two photons peaks, respectively, separated by ∼5 sigma of the coincidence counts at the two output ports of a Mach Zender interferometer as a function of optical path length difference. The research was supported by Seoul R and BD program(NT070127)and by the KRISS

Ultrafast photon number resolving detector with a temperature stabilized si multi pixel photon counter

Energy Technology Data Exchange (ETDEWEB)

Song, Minsoo; Hong, Eugene; Won, Eunil; Yoon, Tai Hyun [Korea Univ., Seoul (Korea, Republic of)

2008-11-15

Quantum information science has been rapidly progressed and matured and matured thanks to the recent developments of the single photon detection technologies. Single photon detectors such as a Si avalanche photo diode(APD)in the infrared, an InGaAs/InP APD in the telecommunication band, and a super conducting transient edge sensor(TES)in the broad region of the spectrum have been widely used. Single photon detectors, however, operating at the ultraviolet to visible (370nm∼800nm)regions has not been actively investigated partly due to the lack of single photon and/or entangled photon sources and the lack of solid state single photon detectors. In this paper, we investigate the single photon detection characteristics of a Si multi pixel photon counter(MPPC), which has a high spectral responsivity between 300nm to 800nm, as a photon number resolving solid state detector. Figure 1 shows the schematic diagram of the single photon detection set up at 399nm by using a temperature stabilized Si MPPC. The output beam of the laser being properly attenuated is directed to the MPPC module, at which fixed number of photo electrons corresponding to incident individual photon are generated at Geiger mode of the Si APD pixels. The detected photo current is converted into a digital signal by using a fast analog to digital converter and a digital oscilloscope stores the time sequence of the photo currents. Figure 2 shows the accumulated charges collected by MPPC at∼10.deg.C showing a clear single photon and two photons peaks, respectively, separated by ∼5 sigma of the coincidence counts at the two output ports of a Mach Zender interferometer as a function of optical path length difference. The research was supported by Seoul R and BD program(NT070127)and by the KRISS.

Generation efficiency of single-photon current pulses in the Geiger mode of silicon avalanche photodiodes

International Nuclear Information System (INIS)

Verkhovtseva, A. V.; Gergel, V. A.

2009-01-01

Statistical fluctuations of the avalanche's multiplication efficiency were studied as applied to the single-photon (Geiger) mode of avalanche photodiodes. The distribution function of partial multiplication factors with an anomalously wide (of the order of the average) dispersion was obtained. Expressions for partial feedback factors were derived in terms of the average gain and the corresponding dependences on the diode's overvoltage were calculated. Final expressions for the photon-electric pulse's conversion were derived by averaging corresponding formulas over the coordinate of initiating photoelectron generation using the functions of optical photon absorption in silicon.

Evaluation of single photon and Geiger mode Lidar for the 3D Elevation Program

Science.gov (United States)

Stoker, Jason M.; Abdullah, Qassim; Nayegandhi, Amar; Winehouse, Jayna

2016-01-01

Data acquired by Harris Corporation’s (Melbourne, FL, USA) Geiger-mode IntelliEarth™ sensor and Sigma Space Corporation’s (Lanham-Seabrook, MD, USA) Single Photon HRQLS sensor were evaluated and compared to accepted 3D Elevation Program (3DEP) data and survey ground control to assess the suitability of these new technologies for the 3DEP. While not able to collect data currently to meet USGS lidar base specification, this is partially due to the fact that the specification was written for linear-mode systems specifically. With little effort on part of the manufacturers of the new lidar systems and the USGS Lidar specifications team, data from these systems could soon serve the 3DEP program and its users. Many of the shortcomings noted in this study have been reported to have been corrected or improved upon in the next generation sensors.

Radiation damage of pixelated photon detector by neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Isamu [KEK, 1-1 Oho Tsukuba 305-0801 (Japan)], E-mail: isamu.nakamura@kek.jp

2009-10-21

Radiation Damage of Pixelated Photon Detector by neutron irradiation is reported. MPPC, one of PPD or Geiger-mode APD, developed by Hamamatsu Photonics, is planned to be used in many high energy physics experiments. In such experiments radiation damage is a serious issue. A series of neutron irradiation tests is performed at the Reactor YAYOI of the University of Tokyo. MPPCs were irradiated at the reactor up to 10{sup 12}neutron/cm{sup 2}. In this paper, the effect of neutron irradiation on the basic characteristics of PPD including gain, noise rate, photon detection efficiency is presented.

Linear LIDAR versus Geiger-mode LIDAR: impact on data properties and data quality

Science.gov (United States)

Ullrich, A.; Pfennigbauer, M.

2016-05-01

LIDAR has become the inevitable technology to provide accurate 3D data fast and reliably even in adverse measurement situations and harsh environments. It provides highly accurate point clouds with a significant number of additional valuable attributes per point. LIDAR systems based on Geiger-mode avalanche photo diode arrays, also called single photon avalanche photo diode arrays, earlier employed for military applications, now seek to enter the commercial market of 3D data acquisition, advertising higher point acquisition speeds from longer ranges compared to conventional techniques. Publications pointing out the advantages of these new systems refer to the other category of LIDAR as "linear LIDAR", as the prime receiver element for detecting the laser echo pulses - avalanche photo diodes - are used in a linear mode of operation. We analyze the differences between the two LIDAR technologies and the fundamental differences in the data they provide. The limitations imposed by physics on both approaches to LIDAR are also addressed and advantages of linear LIDAR over the photon counting approach are discussed.

The performance of photon counting imaging with a Geiger mode silicon avalanche photodiode

International Nuclear Information System (INIS)

Qu, Hui-Ming; Zhang, Yi-Fan; Ji, Zhong-Jie; Chen, Qian

2013-01-01

In principle, photon counting imaging can detect a photon. With the development of low-level-light image intensifier techniques and low-level-light detection devices, photon counting imaging can now detect photon images under extremely low illumination. Based on a Geiger mode silicon avalanche photodiode single photon counter, an experimental system for photon counting imaging was built through two-dimensional scanning of a SPAD (single photon avalanche diode) detector. The feasibility of the imaging platform was validated experimentally. Two images with different characteristics, namely, the USAF 1951 resolution test panel and the image of Lena, were chosen to evaluate the imaging performance of the experimental system. The results were compared and analysed. The imaging properties under various illumination and scanning steps were studied. The lowest illumination limit of the SPAD photon counting imaging was determined. (letter)

Integrated Lens Antennas for Multi-Pixel Receivers

Science.gov (United States)

Lee, Choonsup; Chattopadhyay, Goutam

2011-01-01

Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi-pixel

Extending the dynamic range of silicon photomultipliers without increasing pixel count

International Nuclear Information System (INIS)

Johnson, Kurtis F.

2010-01-01

A silicon photomultiplier, sometimes called 'multipixel photon counter', which we here refer to as a 'SiPM', is a photo-sensitive device built from an avalanche photodiode array of pixels on a common silicon substrate, such that it can detect single photon events. The dimensions of a pixel may vary from 20 to 100 μm and their density can be greater than 1000 per square millimeter. Each pixel in a SiPM operates in Geiger mode and is coupled to the output by a quenching resistor. Although each pixel operates in digital mode, the SiPM is an analog device because all the pixels are read in parallel, making it possible to generate signals within a dynamic range from a single photon to a large number of photons, ultimately limited by the number of pixels on the chip. In this note we describe a simple and general method of increasing the dynamic range of a SiPM beyond that one may naively assume from the shape of the cumulative distribution function of the SiPM response to the average number of photons per pixel. We show that by rendering the incoming flux of photons to be non-uniform in a prescribed manner, a significant increase in dynamic range is achievable. Such re-distribution of the incoming flux may be accomplished with simple, non-focusing lenses, prisms, interference films, mirrors or attenuating films. Almost any optically non-inert interceding device can increase the dynamic range of the SiPM.

Geiger-mueller radiation detector with means for detecting and indicating the existence of radiation overload

International Nuclear Information System (INIS)

Kovacs, T.; Mills, A.P.; Pfeiffer, L.N.

1981-01-01

When subjected to radiation overload existing geiger-mueller counters may give an erroneously low reading, resulting in possible hazard to personnel. The instant invention discloses simple and inexpensive apparatus to remedy this dangerous shortcoming. Depending on the geometry of the detector tube, two possible failure modes have been identified, and circuitry is disclosed to detect the existence of these respective failure modes. The disclosed apparatus indicates the absence of an overload condition, in addition to signaling, by both visible and audible means, the existence of excessive radiation that might result in erroneously low reading of the geiger-mueller counter

Study of micro pixel photon counters for a high granularity scintillator-based hadron calorimeter

International Nuclear Information System (INIS)

D'Ascenzo, N.; Eggemann, A.; Garutti, E.

2007-11-01

A new Geiger mode avalanche photodiode, the Micro Pixel Photon Counter (MPPC), was recently released by Hamamatsu. It has a high photo-detection efficiency in the 420 nm spectral region. This product can represent an elegant candidate for the design of a high granularity scintillator based hadron calorimeter for the International Linear Collider. In fact, the direct readout of the blue scintillation photons with a MPPC is a feasible techological solution. The readout of a plastic scintillator by a MPPC, both mediated by the traditional wavelength shifting fiber, and directly coupled, has been systematically studied. (orig.)

Pixelated transmission-mode diamond X-ray detector.

Science.gov (United States)

Zhou, Tianyi; Ding, Wenxiang; Gaowei, Mengjia; De Geronimo, Gianluigi; Bohon, Jen; Smedley, John; Muller, Erik

2015-11-01

Fabrication and testing of a prototype transmission-mode pixelated diamond X-ray detector (pitch size 60-100 µm), designed to simultaneously measure the flux, position and morphology of an X-ray beam in real time, are described. The pixel density is achieved by lithographically patterning vertical stripes on the front and horizontal stripes on the back of an electronic-grade chemical vapor deposition single-crystal diamond. The bias is rotated through the back horizontal stripes and the current is read out on the front vertical stripes at a rate of ∼ 1 kHz, which leads to an image sampling rate of ∼ 30 Hz. This novel signal readout scheme was tested at beamline X28C at the National Synchrotron Light Source (white beam, 5-15 keV) and at beamline G3 at the Cornell High Energy Synchrotron Source (monochromatic beam, 11.3 keV) with incident beam flux ranges from 1.8 × 10(-2) to 90 W mm(-2). Test results show that the novel detector provides precise beam position (positional noise within 1%) and morphology information (error within 2%), with an additional software-controlled single channel mode providing accurate flux measurement (fluctuation within 1%).

A compact readout system for multi-pixel hybrid photodiodes

International Nuclear Information System (INIS)

Datema, C.P.; Meng, L.J.; Ramsden, D.

1999-01-01

Although the first Multi-pixel Hybrid Photodiode (M-HPD) was developed in the early 1990s by Delft Electronic Products, the main obstacle to its application has been the lack of availability of a compact read-out system. A fast, parallel readout system has been constructed for use with the earlier 25-pixel tube with High-energy Physics applications in mind. The excellent properties of the recently developed multi-pixel hybrid photodiodes (M-HPD) will be easier to exploit following the development of the new hybrid read-out circuits described in this paper. This system will enable all of the required read-out functions to be accommodate on a single board into which the M-HPD is plugged. The design and performance of a versatile system is described in which a trigger-signal, derived from the common-side of the silicon anode in the M-HPD, is used to trigger the readout of the 60-anode pixels in the M-HPD. The multi-channel amplifier section is based on the use of a new, commercial VLSI chip, whilst the read-out sequencer uses a chip of its own design. The common anode signal is processed by a fast amplifier and discriminator to provide a trigger signal when a single event is detected. In the prototype version, the serial analogue output data-stream is processed using a PC-mounted, high speed ADC. Results obtained using the new read-out system in a compact gamma-camera and with a small muon tracking-chamber demonstrate the low-noise performance of the system. The application of this read-out system in other position-sensitive or multi-anode photomultiplier tube applications are also described

Upgrade of the CMS hardron calorimeter for an upgraded LHC

OpenAIRE

Anderson, Jake

2012-01-01

The CMS barrel and endcap hadron calorimeters (Hcal) upgrading the current photo-sensors are hybrid photodiodes (HPDs) to meet the demands of the upgraded luminosity of the LHC. A key aspect of the Hcal upgrade is to add longitudinal segmentation to improve background rejection, energy resolution, and electron isolation at L1 trigger. The increased segmentation can be achieved by replacing the HPD's with multi-pixel Geiger-mode avalanche photodiodes. The upgraded electron...

Super-pixel extraction based on multi-channel pulse coupled neural network

Science.gov (United States)

Xu, GuangZhu; Hu, Song; Zhang, Liu; Zhao, JingJing; Fu, YunXia; Lei, BangJun

2018-04-01

Super-pixel extraction techniques group pixels to form over-segmented image blocks according to the similarity among pixels. Compared with the traditional pixel-based methods, the image descripting method based on super-pixel has advantages of less calculation, being easy to perceive, and has been widely used in image processing and computer vision applications. Pulse coupled neural network (PCNN) is a biologically inspired model, which stems from the phenomenon of synchronous pulse release in the visual cortex of cats. Each PCNN neuron can correspond to a pixel of an input image, and the dynamic firing pattern of each neuron contains both the pixel feature information and its context spatial structural information. In this paper, a new color super-pixel extraction algorithm based on multi-channel pulse coupled neural network (MPCNN) was proposed. The algorithm adopted the block dividing idea of SLIC algorithm, and the image was divided into blocks with same size first. Then, for each image block, the adjacent pixels of each seed with similar color were classified as a group, named a super-pixel. At last, post-processing was adopted for those pixels or pixel blocks which had not been grouped. Experiments show that the proposed method can adjust the number of superpixel and segmentation precision by setting parameters, and has good potential for super-pixel extraction.

Studies on multiplication effect of noises of PPD, and a proposal of a new structure to improve the performance

Energy Technology Data Exchange (ETDEWEB)

Oide, H., E-mail: oide@icepp.s.u-tokyo.ac.j [Department of Physics, University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-0033 (Japan); Murase, T.; Otono, H. [Department of Physics, University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-0033 (Japan); Yamashita, S. [ICEPP, University of Tokyo, 7-3-1 Hongo Bunkyo, Tokyo 113-0033 (Japan)

2010-11-01

Pixelated photon detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-pixel photon counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. We performed measurement of total noise rate, random noise rate, after-pulsing, crosstalk, and relative photon detection efficiency for a 1600 px MPPC. The explosive increase of total noise rate to over-voltage is able to be understood of multiplication effect of after-pulsing and crosstalk. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are all able to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.

Studies on multiplication effect of noises of PPD, and a proposal of a new structure to improve the performance

International Nuclear Information System (INIS)

Oide, H.; Murase, T.; Otono, H.; Yamashita, S.

2010-01-01

Pixelated photon detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-pixel photon counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. We performed measurement of total noise rate, random noise rate, after-pulsing, crosstalk, and relative photon detection efficiency for a 1600 px MPPC. The explosive increase of total noise rate to over-voltage is able to be understood of multiplication effect of after-pulsing and crosstalk. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are all able to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.

Active pixel image sensor with a winner-take-all mode of operation

Science.gov (United States)

Yadid-Pecht, Orly (Inventor); Fossum, Eric R. (Inventor); Mead, Carver (Inventor)

2003-01-01

An integrated CMOS semiconductor imaging device having two modes of operation that can be performed simultaneously to produce an output image and provide information of a brightest or darkest pixel in the image.

Adaptation of an aerosol retrieval algorithm using multi-wavelength and multi-pixel information of satellites (MWPM) to GOSAT/TANSO-CAI

Science.gov (United States)

Hashimoto, M.; Takenaka, H.; Higurashi, A.; Nakajima, T.

2017-12-01

Aerosol in the atmosphere is an important constituent for determining the earth's radiation budget, so the accurate aerosol retrievals from satellite is useful. We have developed a satellite remote sensing algorithm to retrieve the aerosol optical properties using multi-wavelength and multi-pixel information of satellite imagers (MWPM). The method simultaneously derives aerosol optical properties, such as aerosol optical thickness (AOT), single scattering albedo (SSA) and aerosol size information, by using spatial difference of wavelegths (multi-wavelength) and surface reflectances (multi-pixel). The method is useful for aerosol retrieval over spatially heterogeneous surface like an urban region. In this algorithm, the inversion method is a combination of an optimal method and smoothing constraint for the state vector. Furthermore, this method has been combined with the direct radiation transfer calculation (RTM) numerically solved by each iteration step of the non-linear inverse problem, without using look up table (LUT) with several constraints. However, it takes too much computation time. To accelerate the calculation time, we replaced the RTM with an accelerated RTM solver learned by neural network-based method, EXAM (Takenaka et al., 2011), using Rster code. And then, the calculation time was shorternd to about one thouthandth. We applyed MWPM combined with EXAM to GOSAT/TANSO-CAI (Cloud and Aerosol Imager). CAI is a supplement sensor of TANSO-FTS, dedicated to measure cloud and aerosol properties. CAI has four bands, 380, 674, 870 and 1600 nm, and observes in 500 meters resolution for band1, band2 and band3, and 1.5 km for band4. Retrieved parameters are aerosol optical properties, such as aerosol optical thickness (AOT) of fine and coarse mode particles at a wavelenth of 500nm, a volume soot fraction in fine mode particles, and ground surface albedo of each observed wavelength by combining a minimum reflectance method and Fukuda et al. (2013). We will show

Single ion implantation for single donor devices using Geiger mode detectors

International Nuclear Information System (INIS)

Bielejec, E; Seamons, J A; Carroll, M S

2010-01-01

Electronic devices that are designed to use the properties of single atoms such as donors or defects have become a reality with recent demonstrations of donor spectroscopy, single photon emission sources, and magnetic imaging using defect centers in diamond. Ion implantation, an industry standard for atom placement in materials, requires augmentation for single ion capability including a method for detecting a single ion arrival. Integrating single ion detection techniques with the single donor device construction region allows single ion arrival to be assured. Improving detector sensitivity is linked to improving control over the straggle of the ion as well as providing more flexibility in lay-out integration with the active region of the single donor device construction zone by allowing ion sensing at potentially greater distances. Using a remotely located passively gated single ion Geiger mode avalanche diode (SIGMA) detector we have demonstrated 100% detection efficiency at a distance of >75 μm from the center of the collecting junction. This detection efficiency is achieved with sensitivity to ∼600 or fewer electron-hole pairs produced by the implanted ion. Ion detectors with this sensitivity and integrated with a thin dielectric, for example a 5 nm gate oxide, using low energy Sb implantation would have an end of range straggle of -1 and 10 -4 for operation temperatures of ∼300 K and ∼77 K, respectively. Low temperature operation and reduced false, 'dark', counts are critical to achieving high confidence in single ion arrival. For the device performance in this work, the confidence is calculated as a probability of >98% for counting one and only one ion for a false count probability of 10 -4 at an average ion number per gated window of 0.015.

Dual-mode optical microscope based on single-pixel imaging

OpenAIRE

Rodríguez Jiménez, Angel David; Clemente Pesudo, Pedro Javier; Tajahuerce, Enrique; Lancis Sáez, Jesús

2016-01-01

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD...

An Inexpensive Coincidence Circuit for the Pasco Geiger Sensors

CERN Document Server

Fichera, F; Librizzi, F; Riggi, F

2005-01-01

A simple coincidence circuit was devised to carry out educational coincidence experiments involving the use of Geiger counters. The system was tested by commercially available Geiger sensors from PASCO, and is intended to be used in collaboration with high school students and teachers

Tests of the gated mode for Belle II pixel detector

Energy Technology Data Exchange (ETDEWEB)

Prinker, Eduard [Max-Planck-Institute for Physics, Munich (Germany); Collaboration: Belle II-Collaboration

2015-07-01

DEPFET pixel detectors offer intrinsic amplification and very high signal to noise ratio. They form an integral building block for the vertex detector system of the Belle II experiment, which will start data taking in the year 2017 at the SuperKEKB Collider in Japan. A special Test board (Hybrid4) is used, which contains a small version of the DEPFET sensor with a read-out (DCD) and a steering chip (Switcher) attached, both controlled by a field-programmable gate array (FPGA) as the central interface to the computer. In order to keep the luminosity of the collider constant over time, the particle bunch currents have to be topped off by injecting additional bunches at a rate of 50 Hz. The particles in the daughter bunches produce a high rate of background (noisy bunches) for a short period of time, saturating the occupancy of the sensor. Operating the DEPFET sensor in a Gated Mode allows preserving the signals from collisions of normal bunches while protecting the pixels from background signals of the passing noisy bunches. An overview of the Gated Mode and first results is presented.

Studies on multiplication effect of noises of PPDs, and a proposal of a new structure to improve the performance

International Nuclear Information System (INIS)

Oide, H.; Murase, T.; Otono, H.; Yamashita, S.

2010-01-01

Pixelated Photon Detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-Pixel Photon Counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. Test of dark noise rate of a 1600 pixel MPPC as a function of over-voltage at room temperature indicates that the over-voltage is limited up to a few volts because of explosive increase of noise rate. The over-voltage dependence of random noise rate is nevertheless mostly linear. We confirmed this is due to multiplication effect of noises because of after-pulsing and crosstalk. Over-voltage dependence of random noise and photon detection efficiency are qualitatively different. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are possible to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.

Studies on multiplication effect of noises of PPDs, and a proposal of a new structure to improve the performance

Energy Technology Data Exchange (ETDEWEB)

Oide, H., E-mail: oide@icepp.s.u-tokyo.ac.j [Department of Physics, University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo (Japan); Murase, T.; Otono, H. [Department of Physics, University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo (Japan); Yamashita, S. [ICEPP, University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo (Japan)

2010-01-21

Pixelated Photon Detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-Pixel Photon Counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. Test of dark noise rate of a 1600 pixel MPPC as a function of over-voltage at room temperature indicates that the over-voltage is limited up to a few volts because of explosive increase of noise rate. The over-voltage dependence of random noise rate is nevertheless mostly linear. We confirmed this is due to multiplication effect of noises because of after-pulsing and crosstalk. Over-voltage dependence of random noise and photon detection efficiency are qualitatively different. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are possible to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.

Characterization of new hexagonal large area Geiger Avalanche Photodiodes

International Nuclear Information System (INIS)

Boccone, V.; Aguilar, J.A.; Della Volpe, D.; Christov, A.; Montaruli, T.; Rameez, M.; Basili, A.

2013-06-01

Photomultipliers (PMTs) are the standard detector for construction of the current generation of imaging Atmospheric Cherenkov Telescopes (IACTs). Despite impressive improvements in QE and reliability in the last years, these devices suffer from the limitation of being unable to operate in the partially illuminated sky (during full or partial moon periods) as the excess light leads to a significant increase in the rate of ageing of the devices themselves and consequently limit the life of the camera. A viable alternative is the large area Geiger-mode avalanche photodiodes (G-APDs also known as Silicon Photomultipliers or SiPMs) that are commercially available from different producers in various types and dimensions. The sufficiency of the maturity of this technology for application to Cherenkov Astronomy has already been demonstrated by the FACT telescope. One of the camera designs under study for the 4 m Davies Cotton Telescope foresees the utilization of a large area G-APDs coupled to non imaging light concentrators. In collaboration with Hamamatsu and deriving from their current technology, we have designed a new hexagonal shaped large area G-APD HEX S12516 which when coupled to a Winston cone of 24 degrees cutting angle allows for a pixel angular resolution of 0.25 degrees for a f/D 1.4 telescope with a diameter of 4 m. The device, available in 2 different cell size configurations (50 μm and 100 μm), is divided into 4 different channels powered in common cathode mode. A temperature sensor was included for a better temperature evaluation in the characterization phase. The first 3 prototypes were fully characterized and the results are compared to the larger area devices commercially available such as the S10985-050C (2x2 array of 3x3 mm 2 G-APDs). The photo-detection efficiency is measured applying the Poisson statistics method using pulsed LED at 7 different wavelengths from 355 to 670 nm and for different bias over-voltages (V ov ). Optical crosstalk and

A 20 Mfps high frame-depth CMOS burst-mode imager with low power in-pixel NMOS-only passive amplifier

Science.gov (United States)

Wu, L.; San Segundo Bello, D.; Coppejans, P.; Craninckx, J.; Wambacq, P.; Borremans, J.

2017-02-01

This paper presents a 20 Mfps 32 × 84 pixels CMOS burst-mode imager featuring high frame depth with a passive in-pixel amplifier. Compared to the CCD alternatives, CMOS burst-mode imagers are attractive for their low power consumption and integration of circuitry such as ADCs. Due to storage capacitor size and its noise limitations, CMOS burst-mode imagers usually suffer from a lower frame depth than CCD implementations. In order to capture fast transitions over a longer time span, an in-pixel CDS technique has been adopted to reduce the required memory cells for each frame by half. Moreover, integrated with in-pixel CDS, an in-pixel NMOS-only passive amplifier alleviates the kTC noise requirements of the memory bank allowing the usage of smaller capacitors. Specifically, a dense 108-cell MOS memory bank (10fF/cell) has been implemented inside a 30μm pitch pixel, with an area of 25 × 30μm2 occupied by the memory bank. There is an improvement of about 4x in terms of frame depth per pixel area by applying in-pixel CDS and amplification. With the amplifier's gain of 3.3, an FD input-referred RMS noise of 1mV is achieved at 20 Mfps operation. While the amplification is done without burning DC current, including the pixel source follower biasing, the full pixel consumes 10μA at 3.3V supply voltage at full speed. The chip has been fabricated in imec's 130nm CMOS CIS technology.

As the crack in the Geiger counter came. Historical scientific analysis and didactic aspects of the Geiger-Mueller counting tube

International Nuclear Information System (INIS)

Korff, Sebastian

2014-01-01

This thesis studies the creation and establishment history of this instrument called first electron counting tube in the years 1928 and 1929. It deals thereby with the last two years of the common work of Hans Geiger and Walter Mueller, from which the measuring instrument later renamed to Geiger-Mueller counting tube. The results of this scientific case study are didactically worked out and made usable for the teaching of physics in the school.

Modelization, fabrication and evaluation avalanche photodiodes polarized in Geiger mode for the single photon in astrophysics applications

International Nuclear Information System (INIS)

Pellion, D.

2008-12-01

The genesis of the work presented in this this is in the field of very high energy astrophysics. One century ago, scientists identified a new type of messenger coming from space: cosmic rays. This radiation consists of particles (photons or other) of very high energy which bombard the Earth permanently. The passage of cosmic radiations in the Earth's atmosphere results in the creation of briefs luminous flashes (5 ns) of very low intensity (1 pW), a Cherenkov flash, and then becomes visible on the ground. In the current state of the art the best detector of light today is the Photomultiplier tube (PMT), thanks to its characteristics of sensitivity and speed. But there are some drawbacks: low quantum efficiency, cost, weight etc. We present in this thesis a new alternative technology: silicon photon counters, made of photodiodes polarized in Geiger mode. This operating mode makes it possible to obtain an effect of multiplication comparable to that of the PMT. A physical and electrical model was developed to reproduce the behaviour of this detector. We then present in this thesis work an original technological process allowing the realization of these devices in the Center of Technology of LAAS-CNRS, with the simulation of each operation of the process. We developed a scheme for the electric characterization of the device, from the static mode to the dynamic mode, in order to check conformity with SILVACO simulations and to the initial model. Results are already excellent, given this is only a first prototype step, and comparable with the results published in the literature. These silicon devices can intervene in all the applications where there is a photomultiplier and replace it. The applications are thus very numerous and the growth of the market of these detectors is very fast. We present a first astrophysical experiment installed at the 'Pic du Midi' site which has detected Cherenkov flashes from cosmic rays with this new semiconductor technology. (author)

A new poly-Si TFT compensation pixel circuit employing AC driving mode for AMOLED displays

International Nuclear Information System (INIS)

Song Xiaofeng; Luo Jianguo; Wu Weijing; Peng Junbiao; Zhou Lei; Zhang Lirong

2013-01-01

This paper presents a new poly-Si pixel circuit employing AC driving mode for active matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit, which consists of one driving thin-film transistor (TFT), three switching TFTs, and one storage capacitor, can effectively compensate for the threshold voltage variation in poly-Si and the OLED degradation. As there is no light emission, except for during the emitting period, and a small number of devices used in the proposed pixel circuit, a high contrast ratio and a high pixel aperture ratio can be easily achieved. Simulation results by SMART-SPICE software show that the non-uniformity of the OLED current for the proposed pixel circuit is significantly decreased (< 10%) with an average value of 2.63%, while that of the conventional 2T1C is 103%. Thus the brightness uniformity of AMOLED displays can be improved by using the proposed pixel circuit. (semiconductor integrated circuits)

Modelization, fabrication and evaluation avalanche photodiodes polarized in Geiger mode for the single photon in astrophysics applications; Modelisation, fabrication et evaluation des photodiodes a avalanche polarisees en mode Geiger pour la detection du photon unique dans les applications Astrophysiques

Energy Technology Data Exchange (ETDEWEB)

Pellion, D

2008-12-15

The genesis of the work presented in this this is in the field of very high energy astrophysics. One century ago, scientists identified a new type of messenger coming from space: cosmic rays. This radiation consists of particles (photons or other) of very high energy which bombard the Earth permanently. The passage of cosmic radiations in the Earth's atmosphere results in the creation of briefs luminous flashes (5 ns) of very low intensity (1 pW), a Cherenkov flash, and then becomes visible on the ground. In the current state of the art the best detector of light today is the Photomultiplier tube (PMT), thanks to its characteristics of sensitivity and speed. But there are some drawbacks: low quantum efficiency, cost, weight etc. We present in this thesis a new alternative technology: silicon photon counters, made of photodiodes polarized in Geiger mode. This operating mode makes it possible to obtain an effect of multiplication comparable to that of the PMT. A physical and electrical model was developed to reproduce the behaviour of this detector. We then present in this thesis work an original technological process allowing the realization of these devices in the Center of Technology of LAAS-CNRS, with the simulation of each operation of the process. We developed a scheme for the electric characterization of the device, from the static mode to the dynamic mode, in order to check conformity with SILVACO simulations and to the initial model. Results are already excellent, given this is only a first prototype step, and comparable with the results published in the literature. These silicon devices can intervene in all the applications where there is a photomultiplier and replace it. The applications are thus very numerous and the growth of the market of these detectors is very fast. We present a first astrophysical experiment installed at the 'Pic du Midi' site which has detected Cherenkov flashes from cosmic rays with this new semiconductor technology

Developments of Highly Multiplexed, Multi-chroic Pixels for Balloon-Borne Platforms

Science.gov (United States)

Aubin, F.; Hanany, S.; Johnson, B. R.; Lee, A.; Suzuki, A.; Westbrook, B.; Young, K.

2018-02-01

We present our work to develop and characterize low thermal conductance bolometers that are part of sinuous antenna multi-chroic pixels (SAMP). We use longer, thinner and meandered bolometer legs to achieve 9 pW/K thermal conductance bolometers. We also discuss the development of inductor-capacitor chips operated at 4 K to extend the multiplexing factor of the frequency domain multiplexing to 105, an increase of 60% compared to the factor currently demonstrated for this readout system. This technology development is motivated by EBEX-IDS, a balloon-borne polarimeter designed to characterize the polarization of foregrounds and to detect the primordial gravity waves through their B-mode signature on the polarization of the cosmic microwave background. EBEX-IDS will operate 20,562 transition edge sensor bolometers spread over 7 frequency bands between 150 and 360 GHz. Balloon and satellite platforms enable observations at frequencies inaccessible from the ground and with higher instantaneous sensitivity. This development improves the readiness of the SAMP and frequency domain readout technologies for future satellite applications.

Design and Characterization of 64K Pixels Chips Working in Single Photon Processing Mode

CERN Document Server

Llopart Cudie, Xavier; Campbell, M

2007-01-01

Progress in CMOS technology and in fine pitch bump bonding has made possible the development of high granularity single photon counting detectors for X-ray imaging. This thesis studies the design and characterization of three pulse processing chips with 65536 square pixels of 55 µm x 55 µm designed in a commercial 0.25 µm 6-metal CMOS technology. The 3 chips share the same architecture and dimensions and are named Medipix2, Mpix2MXR20 and Timepix. The Medipix2 chip is a pixel detector readout chip consisting of 256 x 256 identical elements, each working in single photon counting mode for positive or negative input charge signals. The preamplifier feedback provides compensation for detector leakage current on a pixel by pixel basis. Two identical pulse height discriminators are used to define an energy window. Every event falling inside the energy window is counted with a 13 bit pseudo-random counter. The counter logic, based in a shift register, also behaves as the input/output register for the pixel. Each...

As the crack in the Geiger counter came. Historical scientific analysis and didactic aspects of the Geiger-Mueller counting tube; Wie das Knacken in den Geigerzaehler kam. Wissenschaftshistorische Analyse und fachdidaktische Aspekte des Geiger-Mueller Zaehlrohrs

Energy Technology Data Exchange (ETDEWEB)

Korff, Sebastian

2014-11-10

This thesis studies the creation and establishment history of this instrument called first electron counting tube in the years 1928 and 1929. It deals thereby with the last two years of the common work of Hans Geiger and Walter Mueller, from which the measuring instrument later renamed to Geiger-Mueller counting tube. The results of this scientific case study are didactically worked out and made usable for the teaching of physics in the school.

A Multi-Resolution Mode CMOS Image Sensor with a Novel Two-Step Single-Slope ADC for Intelligent Surveillance Systems

Directory of Open Access Journals (Sweden)

Daehyeok Kim

2017-06-01

Full Text Available In this paper, we present a multi-resolution mode CMOS image sensor (CIS for intelligent surveillance system (ISS applications. A low column fixed-pattern noise (CFPN comparator is proposed in 8-bit two-step single-slope analog-to-digital converter (TSSS ADC for the CIS that supports normal, 1/2, 1/4, 1/8, 1/16, 1/32, and 1/64 mode of pixel resolution. We show that the scaled-resolution images enable CIS to reduce total power consumption while images hold steady without events. A prototype sensor of 176 × 144 pixels has been fabricated with a 0.18 μm 1-poly 4-metal CMOS process. The area of 4-shared 4T-active pixel sensor (APS is 4.4 μm × 4.4 μm and the total chip size is 2.35 mm × 2.35 mm. The maximum power consumption is 10 mW (with full resolution with supply voltages of 3.3 V (analog and 1.8 V (digital and 14 frame/s of frame rates.

A Multi-Resolution Mode CMOS Image Sensor with a Novel Two-Step Single-Slope ADC for Intelligent Surveillance Systems.

Science.gov (United States)

Kim, Daehyeok; Song, Minkyu; Choe, Byeongseong; Kim, Soo Youn

2017-06-25

In this paper, we present a multi-resolution mode CMOS image sensor (CIS) for intelligent surveillance system (ISS) applications. A low column fixed-pattern noise (CFPN) comparator is proposed in 8-bit two-step single-slope analog-to-digital converter (TSSS ADC) for the CIS that supports normal, 1/2, 1/4, 1/8, 1/16, 1/32, and 1/64 mode of pixel resolution. We show that the scaled-resolution images enable CIS to reduce total power consumption while images hold steady without events. A prototype sensor of 176 × 144 pixels has been fabricated with a 0.18 μm 1-poly 4-metal CMOS process. The area of 4-shared 4T-active pixel sensor (APS) is 4.4 μm × 4.4 μm and the total chip size is 2.35 mm × 2.35 mm. The maximum power consumption is 10 mW (with full resolution) with supply voltages of 3.3 V (analog) and 1.8 V (digital) and 14 frame/s of frame rates.

Analysis and synthesis of multi-qubit, multi-mode quantum devices

Energy Technology Data Exchange (ETDEWEB)

Solgun, Firat

2015-03-27

In this thesis we propose new methods in multi-qubit multi-mode circuit quantum electrodynamics (circuit-QED) architectures. First we describe a direct parity measurement method for three qubits, which can be realized in 2D circuit-QED with a possible extension to four qubits in a 3D circuit-QED setup for the implementation of the surface code. In Chapter 3 we show how to derive Hamiltonians and compute relaxation rates of the multi-mode superconducting microwave circuits consisting of single Josephson junctions using an exact impedance synthesis technique (the Brune synthesis) and applying previous formalisms for lumped element circuit quantization. In the rest of the thesis we extend our method to multi-junction (multi-qubit) multi-mode circuits through the use of state-space descriptions which allows us to quantize any multiport microwave superconducting circuit with a reciprocal lossy impedance response.

Design and Optimization of Multi-Pixel Transition-Edge Sensors for X-Ray Astronomy Applications

Science.gov (United States)

Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron Michael; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.;

Adjoint Methods for Adjusting Three-Dimensional Atmosphere and Surface Properties to Fit Multi-Angle Multi-Pixel Polarimetric Measurements

Science.gov (United States)

Martin, William G.; Cairns, Brian; Bal, Guillaume

2014-01-01

This paper derives an efficient procedure for using the three-dimensional (3D) vector radiative transfer equation (VRTE) to adjust atmosphere and surface properties and improve their fit with multi-angle/multi-pixel radiometric and polarimetric measurements of scattered sunlight. The proposed adjoint method uses the 3D VRTE to compute the measurement misfit function and the adjoint 3D VRTE to compute its gradient with respect to all unknown parameters. In the remote sensing problems of interest, the scalar-valued misfit function quantifies agreement with data as a function of atmosphere and surface properties, and its gradient guides the search through this parameter space. Remote sensing of the atmosphere and surface in a three-dimensional region may require thousands of unknown parameters and millions of data points. Many approaches would require calls to the 3D VRTE solver in proportion to the number of unknown parameters or measurements. To avoid this issue of scale, we focus on computing the gradient of the misfit function as an alternative to the Jacobian of the measurement operator. The resulting adjoint method provides a way to adjust 3D atmosphere and surface properties with only two calls to the 3D VRTE solver for each spectral channel, regardless of the number of retrieval parameters, measurement view angles or pixels. This gives a procedure for adjusting atmosphere and surface parameters that will scale to the large problems of 3D remote sensing. For certain types of multi-angle/multi-pixel polarimetric measurements, this encourages the development of a new class of three-dimensional retrieval algorithms with more flexible parametrizations of spatial heterogeneity, less reliance on data screening procedures, and improved coverage in terms of the resolved physical processes in the Earth?s atmosphere.

Power and area efficient 4-bit column-level ADC in a CMOS pixel sensor for the ILD vertex detector

International Nuclear Information System (INIS)

Zhang, L; Morel, F; Hu-Guo, Ch; Hu, Y

2013-01-01

A 48 × 64 pixels prototype CMOS pixel sensor (CPS) integrated with 4-bit column-level, self triggered ADCs for the outer layers of the ILD vertex detector (VTX) was developed and fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation. The ADCs accommodating the pixel read out in a rolling shutter mode complete the conversion by performing a multi-bit/step approximation. The design was optimised for power saving at sampling frequency. The prototype sensor is currently at the stage of being started testing and evaluation. So what is described is based on post simulation results rather than test data. This 4-bit ADC dissipates, at a 3-V supply and 6.25-MS/s sampling rate, 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. Its footprint amounts to 35 × 545 μm 2 .

Slice sensitivity profiles and pixel noise of multi-slice CT in comparison with single-slice CT

International Nuclear Information System (INIS)

Schorn, C.; Obenauer, S.; Funke, M.; Hermann, K.P.; Kopka, L.; Grabbe, E.

1999-01-01

Purpose: Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT. Methods: Slice sensitivity profiles and pixel noise of a multi-slice CT equiped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies. Results: For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation. Conclusions: Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing. (orig.) [de

Polarimetric analysis of a CdZnTe spectro-imager under multi-pixel irradiation conditions

Energy Technology Data Exchange (ETDEWEB)

Pinto, M. [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); Physics Department, University of Coimbra, Coimbra (Portugal); Curado da Silva, R.M., E-mail: rui.silva@coimbra.lip.pt [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); Physics Department, University of Coimbra, Coimbra (Portugal); Maia, J.M. [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); Physics Department, University of Beira-Interior, Covilhã (Portugal); Simões, N. [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); Physics Department, University of Coimbra, Coimbra (Portugal); Marques, J. [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); Centro de Astrofísica, Universidade do Porto, Porto (Portugal); Pereira, L.; Trindade, A.M.F. [LIP-Laboratório de Instrumentação e Física Experimental de Partículas (Portugal); and others

2016-12-21

So far, polarimetry in high-energy astrophysics has been insufficiently explored due to the complexity of the required detection, electronic and signal processing systems. However, its importance is today largely recognized by the astrophysical community, therefore the next generation of high-energy space instruments will certainly provide polarimetric observations, contemporaneously with spectroscopy and imaging. We have been participating in high-energy observatory proposals submitted to ESA Cosmic Vision calls, such as GRI (Gamma-Ray Imager), DUAL and ASTROGAM, where the main instrument was a spectro-imager with polarimetric capabilities. More recently, the H2020 AHEAD project was launched with the objective to promote more coherent and mature future high-energy space mission proposals. In this context of high-energy proposal development, we have tested a CdZnTe detection plane prototype polarimeter under a partially polarized gamma-ray beam generated from an aluminum target irradiated by a {sup 22}Na (511 keV) radioactive source. The polarized beam cross section was 1 cm{sup 2}, allowing the irradiation of a wide multi-pixelated area where all the pixels operate simultaneously as a scatterer and as an absorber. The methods implemented to analyze such multi-pixel irradiation are similar to those required to analyze a spectro-imager polarimeter operating in space, since celestial source photons should irradiate its full pixilated area. Correction methods to mitigate systematic errors inherent to CdZnTe and to the experimental conditions were also implemented. The polarization level (~40%) and the polarization angle (precision of ±5° up to ±9°) obtained under multi-pixel irradiation conditions are presented and compared with simulated data.

107.5 Gb/s 850 nm multi- and single-mode VCSEL transmission over 10 and 100 m of multi-mode fiber

DEFF Research Database (Denmark)

Puerta Ramírez, Rafael; Agustin, M.; Chorchos, L.

2016-01-01

First time successful 107.5 Gb/s MultiCAP 850 nm OM4 MMF transmissions over 10 m with multi-mode VCSEL and up to 100 m with single-mode VCSEL are demonstrated, with BER below 7% overhead FEC limit measured for each case.......First time successful 107.5 Gb/s MultiCAP 850 nm OM4 MMF transmissions over 10 m with multi-mode VCSEL and up to 100 m with single-mode VCSEL are demonstrated, with BER below 7% overhead FEC limit measured for each case....

Concepts for space nuclear multi-mode reactors

International Nuclear Information System (INIS)

Myrabo, L.; Botts, T.E.; Powell, J.R.

1983-01-01

A number of nuclear multi-mode reactor power plants are conceptualized for use with solid core, fixed particle bed and rotating particle bed reactors. Multi-mode systems generate high peak electrical power in the open cycle mode, with MHD generator or turbogenerator converters and cryogenically stored coolants. Low level stationkeeping power and auxiliary reactor cooling (i.e., for the removal of reactor afterheat) are provided in a closed cycle mode. Depending on reactor design, heat transfer to the low power converters can be accomplished by heat pipes, liquid metal coolants or high pressure gas coolants. Candidate low power conversion cycles include Brayton turbogenerator, Rankine turbogenerator, thermoelectric and thermionic approaches. A methodology is suggested for estimating the system mass of multi-mode nuclear power plants as a function of peak electric power level and required mission run time. The masses of closed cycle nuclear and open cycle chemical power systems are briefly examined to identify the regime of superiority for nuclear multi-mode systems. Key research and technology issues for such power plants are also identified

Compact Gaussian quantum computation by multi-pixel homodyne detection

International Nuclear Information System (INIS)

Ferrini, G; Fabre, C; Treps, N; Gazeau, J P; Coudreau, T

2013-01-01

We study the possibility of producing and detecting continuous variable cluster states in an extremely compact optical setup. This method is based on a multi-pixel homodyne detection system recently demonstrated experimentally, which includes classical data post-processing. It allows the incorporation of the linear optics network, usually employed in standard experiments for the production of cluster states, in the stage of the measurement. After giving an example of cluster state generation by this method, we further study how this procedure can be generalized to perform Gaussian quantum computation. (paper)

Updated world map of the Köppen-Geiger climate classification

Directory of Open Access Journals (Sweden)

M. C. Peel

2007-10-01

Full Text Available Although now over 100 years old, the classification of climate originally formulated by Wladimir Köppen and modified by his collaborators and successors, is still in widespread use. It is widely used in teaching school and undergraduate courses on climate. It is also still in regular use by researchers across a range of disciplines as a basis for climatic regionalisation of variables and for assessing the output of global climate models. Here we have produced a new global map of climate using the Köppen-Geiger system based on a large global data set of long-term monthly precipitation and temperature station time series. Climatic variables used in the Köppen-Geiger system were calculated at each station and interpolated between stations using a two-dimensional (latitude and longitude thin-plate spline with tension onto a 0.1°×0.1° grid for each continent. We discuss some problems in dealing with sites that are not uniquely classified into one climate type by the Köppen-Geiger system and assess the outcomes on a continent by continent basis. Globally the most common climate type by land area is BWh (14.2%, Hot desert followed by Aw (11.5%, Tropical savannah. The updated world Köppen-Geiger climate map is freely available electronically in the Supplementary Material Section.

Segmentation of arterial vessel wall motion to sub-pixel resolution using M-mode ultrasound.

Science.gov (United States)

Fancourt, Craig; Azer, Karim; Ramcharan, Sharmilee L; Bunzel, Michelle; Cambell, Barry R; Sachs, Jeffrey R; Walker, Matthew

2008-01-01

We describe a method for segmenting arterial vessel wall motion to sub-pixel resolution, using the returns from M-mode ultrasound. The technique involves measuring the spatial offset between all pairs of scans from their cross-correlation, converting the spatial offsets to relative wall motion through a global optimization, and finally translating from relative to absolute wall motion by interpolation over the M-mode image. The resulting detailed wall distension waveform has the potential to enhance existing vascular biomarkers, such as strain and compliance, as well as enable new ones.

Feasibility study of multi-pixel retrieval of optical thickness and droplet effective radius of inhomogeneous clouds using deep learning

Science.gov (United States)

Okamura, Rintaro; Iwabuchi, Hironobu; Schmidt, K. Sebastian

2017-12-01

Three-dimensional (3-D) radiative-transfer effects are a major source of retrieval errors in satellite-based optical remote sensing of clouds. The challenge is that 3-D effects manifest themselves across multiple satellite pixels, which traditional single-pixel approaches cannot capture. In this study, we present two multi-pixel retrieval approaches based on deep learning, a technique that is becoming increasingly successful for complex problems in engineering and other areas. Specifically, we use deep neural networks (DNNs) to obtain multi-pixel estimates of cloud optical thickness and column-mean cloud droplet effective radius from multispectral, multi-pixel radiances. The first DNN method corrects traditional bispectral retrievals based on the plane-parallel homogeneous cloud assumption using the reflectances at the same two wavelengths. The other DNN method uses so-called convolutional layers and retrieves cloud properties directly from the reflectances at four wavelengths. The DNN methods are trained and tested on cloud fields from large-eddy simulations used as input to a 3-D radiative-transfer model to simulate upward radiances. The second DNN-based retrieval, sidestepping the bispectral retrieval step through convolutional layers, is shown to be more accurate. It reduces 3-D radiative-transfer effects that would otherwise affect the radiance values and estimates cloud properties robustly even for optically thick clouds.

Polarization Characterization of a Multi-Moded Feed Structure

Data.gov (United States)

National Aeronautics and Space Administration — The Polarization Characterization of a Multi-Moded Feed Structure projects characterize the polarization response of a multi-moded feed horn as an innovative...

Characterization of a pixelated CdTe Timepix detector operated in ToT mode

International Nuclear Information System (INIS)

Billoud, T.; Leroy, C.; Papadatos, C.; Roux, J.S.; Pichotka, M.; Pospisil, S.

2017-01-01

A 1 mm thick CdTe sensor bump-bonded to a Timepix readout chip operating in Time-over-Threshold (ToT) mode has been characterized in view of possible applications in particle and medical physics. The CdTe sensor layer was segmented into 256 × 256 pixels, with a pixel pitch of 55  μm. This CdTe Timepix device, of ohmic contact type, has been exposed to alpha-particles and photons from an 241 Am source, photons from a 137 Cs source, and protons of different energies (0.8–10 MeV) delivered by the University of Montreal Tandem Accelerator. The device was irradiated on the negatively biased backside electrode. An X-ray per-pixel calibration commonly used for this type of detector was done and its accuracy and resolution were assessed and compared to those of a 300  μm thick silicon Timepix device. The electron mobility-lifetime product (μ e τ e ) of CdTe for protons of low energy has been obtained from the Hecht equation. Possible polarization effects have been also investigated. Finally, information about the homogeneity of the detector was obtained from X-ray irradiation.

Statistical analysis of natural radiation levels inside the UNICAMP campus through the use of Geiger-Muller counter; Analise estatistica dos niveis de radiacao natural dentro da UNICAMP atraves do uso de contador Geiger-Muller

Energy Technology Data Exchange (ETDEWEB)

Fontolan, Juliana A.; Biral, Antonio Renato P., E-mail: fontolanjuliana@gmail.com.br, E-mail: biral@ceb.unicamp.br [Hospital das Clinicas (CEB/UNICAMP), Campinas, SP (Brazil). Centro de Engenharia Biomedica

2013-07-01

It is known that the distribution at time intervals of random and unrelated events leads to the Poisson distribution . This work aims to study the distribution in time intervals of events resulting from radioactive decay of atoms present in the UNICAMP where activities involving the use of ionizing radiation are performed environments . The proposal is that the distribution surveys at intervals of these events in different locations of the university are carried out through the use of a Geiger-Mueller tube . In a next step , the evaluation of distributions obtained by using non- parametric statistics (Chi- square and Kolmogorov Smirnoff) will be taken . For analyzes involving correlations we intend to use the ANOVA (Analysis of Variance) statistical tool . Measured in six different places within the Campinas , with the use of Geiger- Muller its count mode and a time window of 20 seconds was performed . Through statistical tools chi- square and Kolmogorov Smirnoff tests, using the EXCEL program , it was observed that the distributions actually refer to a Poisson distribution. Finally, the next step is to perform analyzes involving correlations using the statistical tool ANOVA.

PLC-based mode multi/demultiplexers for mode division multiplexing

Science.gov (United States)

Saitoh, Kunimasa; Hanzawa, Nobutomo; Sakamoto, Taiji; Fujisawa, Takeshi; Yamashita, Yoko; Matsui, Takashi; Tsujikawa, Kyozo; Nakajima, Kazuhide

2017-02-01

Recently developed PLC-based mode multi/demultiplexers (MUX/DEMUXs) for mode division multiplexing (MDM) transmission are reviewed. We firstly show the operation principle and basic characteristics of PLC-based MUX/DEMUXs with an asymmetric directional coupler (ADC). We then demonstrate the 3-mode (2LP-mode) multiplexing of the LP01, LP11a, and LP11b modes by using fabricated PLC-based mode MUX/DEMUX on one chip. In order to excite LP11b mode in the same plane, a PLC-based LP11 mode rotator is introduced. Finally, we show the PLC-based 6-mode (4LP-mode) MUX/DEMUX with a uniform height by using ADCs, LP11 mode rotators, and tapered waveguides. It is shown that the LP21a mode can be excited from the LP11b mode by using ADC, and the two nearly degenerated LP21b and LP02 modes can be (de)multiplexed separately by using tapered mode converter from E13 (E31) mode to LP21b (LP02) mode.

A quantum-classical simulation of a multi-surface multi-mode ...

Indian Academy of Sciences (India)

Multi surface multi mode quantum dynamics; parallelized quantum classical approach; TDDVR method. 1. ... cal simulation on molecular system is a great cha- llenge for ..... on a multiple core cluster with shared memory using. OpenMP based ...

3D Cloud Tomography, Followed by Mean Optical and Microphysical Properties, with Multi-Angle/Multi-Pixel Data

Science.gov (United States)

Davis, A. B.; von Allmen, P. A.; Marshak, A.; Bal, G.

2010-12-01

The geometrical assumption in all operational cloud remote sensing algorithms is that clouds are plane-parallel slabs, which applies relatively well to the most uniform stratus layers. Its benefit is to justify using classic 1D radiative transfer (RT) theory, where angular details (solar, viewing, azimuthal) are fully accounted for and precise phase functions can be used, to generate the look-up tables used in the retrievals. Unsurprisingly, these algorithms catastrophically fail when applied to cumulus-type clouds, which are highly 3D. This is unfortunate for the cloud-process modeling community that may thrive on in situ airborne data, but would very much like to use satellite data for more than illustrations in their presentations and publications. So, how can we obtain quantitative information from space-based observations of finite aspect ratio clouds? Cloud base/top heights, vertically projected area, mean liquid water content (LWC), and volume-averaged droplet size would be a good start. Motivated by this science need, we present a new approach suitable for sparse cumulus fields where we turn the tables on the standard procedure in cloud remote sensing. We make no a priori assumption about cloud shape, save an approximately flat base, but use brutal approximations about the RT that is necessarily 3D. Indeed, the first order of business is to roughly determine the cloud's outer shape in one of two ways, which we will frame as competing initial guesses for the next phase of shape refinement and volume-averaged microphysical parameter estimation. Both steps use multi-pixel/multi-angle techniques amenable to MISR data, the latter adding a bi-spectral dimension using collocated MODIS data. One approach to rough cloud shape determination is to fit the multi-pixel/multi-angle data with a geometric primitive such as a scalene hemi-ellipsoid with 7 parameters (translation in 3D space, 3 semi-axes, 1 azimuthal orientation); for the radiometry, a simple radiosity

Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector

Science.gov (United States)

Huntington, Andrew

2013-01-01

The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.

Leakage current measurements on pixelated CdZnTe detectors

International Nuclear Information System (INIS)

Dirks, B.P.F.; Blondel, C.; Daly, F.; Gevin, O.; Limousin, O.; Lugiez, F.

2006-01-01

In the field of the R and D of a new generation hard X-ray cameras for space applications we focus on the use of pixelated CdTe or CdZnTe semiconductor detectors. They are covered with 64 (0.9x0.9 mm 2 ) or 256 (0.5x0.5 mm 2 ) pixels, surrounded by a guard ring and operate in the energy ranging from several keV to 1 MeV, at temperatures between -20 and +20 o C. A critical parameter in the characterisation of these detectors is the leakage current per pixel under polarisation (∼50-500 V/mm). In operation mode each pixel will be read-out by an integrated spectroscopy channel of the multi-channel IDeF-X ASIC currently developed in our lab. The design and functionality of the ASIC depends directly on the direction and value of the current. A dedicated and highly insulating electronics circuit is designed to automatically measure the current in each individual pixel, which is in the order of tens of pico-amperes. Leakage current maps of different CdZnTe detectors of 2 and 6 mm thick and at various temperatures are presented and discussed. Defect density diagnostics have been performed by calculation of the activation energy of the material

The ALICE Silicon Pixel Detector System (SPD)

CERN Document Server

Kluge, A; Antinori, Federico; Burns, M; Cali, I A; Campbell, M; Caselle, M; Ceresa, S; Dima, R; Elias, D; Fabris, D; Krivda, Marian; Librizzi, F; Manzari, Vito; Morel, M; Moretto, Sandra; Osmic, F; Pappalardo, G S; Pepato, Adriano; Pulvirenti, A; Riedler, P; Riggi, F; Santoro, R; Stefanini, G; Torcato De Matos, C; Turrisi, R; Tydesjo, H; Viesti, G; PH-EP

2007-01-01

The ALICE silicon pixel detector (SPD) comprises the two innermost layers of the ALICE inner tracker system. The SPD includes 120 detector modules (half-staves) each consisting of 10 ALICE pixel chips bump bonded to two silicon sensors and one multi-chip read-out module. Each pixel chip contains 8192 active cells, so that the total number of pixel cells in the SPD is ≈ 107. The on-detector read-out is based on a multi-chip-module containing 4 ASICs and an optical transceiver module. The constraints on material budget and detector module dimensions are very demanding.

Two-mode PLC-based mode multi/demultiplexer for mode and wavelength division multiplexed transmission.

Science.gov (United States)

Hanzawa, Nobutomo; Saitoh, Kuimasa; Sakamoto, Taiji; Matsui, Takashi; Tsujikawa, Kyozo; Koshiba, Masanori; Yamamoto, Fumihiko

2013-11-04

We proposed a PLC-based mode multi/demultiplexer (MUX/DEMUX) with an asymmetric parallel waveguide for mode division multiplexed (MDM) transmission. The mode MUX/DEMUX including a mode conversion function with an asymmetric parallel waveguide can be realized by matching the effective indices of the LP(01) and LP(11) modes of two waveguides. We report the design of a mode MUX/DEMUX that can support C-band WDM-MDM transmission. The fabricated mode MUX/DEMUX realized a low insertion loss of less than 1.3 dB and high a mode extinction ratio that exceeded 15 dB. We used the fabricated mode MUX/DEMUX to achieve a successful 2 mode x 4 wavelength x 10 Gbps transmission over a 9 km two-mode fiber with a penalty of less than 1 dB.

iPadPix—A novel educational tool to visualise radioactivity measured by a hybrid pixel detector

International Nuclear Information System (INIS)

Keller, O.; Schmeling, S.; Müller, A.; Benoit, M.

2016-01-01

With the ability to attribute signatures of ionising radiation to certain particle types, pixel detectors offer a unique advantage over the traditional use of Geiger-Müller tubes also in educational settings. We demonstrate in this work how a Timepix readout chip combined with a standard 300μm pixelated silicon sensor can be used to visualise radioactivity in real-time and by means of augmented reality. The chip family is the result of technology transfer from High Energy Physics at CERN and facilitated by the Medipix Collaboration. This article summarises the development of a prototype based on an iPad mini and open source software detailed in ref. [1]. Appropriate experimental activities that explore natural radioactivity and everyday objects are given to demonstrate the use of this new tool in educational settings.

iPadPix—A novel educational tool to visualise radioactivity measured by a hybrid pixel detector

CERN Document Server

Keller, O; Müller, A; Benoit, M

2016-01-01

With the ability to attribute signatures of ionising radiation to certain particle types, pixel detectors offer a unique advantage over the traditional use of Geiger-Müller tubes also in educational settings. We demonstrate in this work how a Timepix readout chip combined with a standard 300 μ m pixelated silicon sensor can be used to visualise radioactivity in real-time and by means of augmented reality. The chip family is the result of technology transfer from High Energy Physics at CERN and facilitated by the Medipix Collaboration. This article summarises the development of a prototype based on an iPad mini and open source software detailed in ref. [1]. Appropriate experimental activities that explore natural radioactivity and everyday objects are given to demonstrate the use of this new tool in educational settings.

Statistical analysis of natural radiation levels inside the UNICAMP campus through the use of Geiger-Muller counter

International Nuclear Information System (INIS)

Fontolan, Juliana A.; Biral, Antonio Renato P.

2013-01-01

It is known that the distribution at time intervals of random and unrelated events leads to the Poisson distribution . This work aims to study the distribution in time intervals of events resulting from radioactive decay of atoms present in the UNICAMP where activities involving the use of ionizing radiation are performed environments . The proposal is that the distribution surveys at intervals of these events in different locations of the university are carried out through the use of a Geiger-Mueller tube . In a next step , the evaluation of distributions obtained by using non- parametric statistics (Chi- square and Kolmogorov Smirnoff) will be taken . For analyzes involving correlations we intend to use the ANOVA (Analysis of Variance) statistical tool . Measured in six different places within the Campinas , with the use of Geiger- Muller its count mode and a time window of 20 seconds was performed . Through statistical tools chi- square and Kolmogorov Smirnoff tests, using the EXCEL program , it was observed that the distributions actually refer to a Poisson distribution. Finally, the next step is to perform analyzes involving correlations using the statistical tool ANOVA

Object recognition through a multi-mode fiber

Science.gov (United States)

Takagi, Ryosuke; Horisaki, Ryoichi; Tanida, Jun

2017-04-01

We present a method of recognizing an object through a multi-mode fiber. A number of speckle patterns transmitted through a multi-mode fiber are provided to a classifier based on machine learning. We experimentally demonstrated binary classification of face and non-face targets based on the method. The measurement process of the experimental setup was random and nonlinear because a multi-mode fiber is a typical strongly scattering medium and any reference light was not used in our setup. Comparisons between three supervised learning methods, support vector machine, adaptive boosting, and neural network, are also provided. All of those learning methods achieved high accuracy rates at about 90% for the classification. The approach presented here can realize a compact and smart optical sensor. It is practically useful for medical applications, such as endoscopy. Also our study indicated a promising utilization of artificial intelligence, which has rapidly progressed, for reducing optical and computational costs in optical sensing systems.

Geiger counters of gamma rays with a bismuth cathode; Compteurs de geiger a rayons gamma a cathode de bismuth

Energy Technology Data Exchange (ETDEWEB)

Meunier, R; Legrand, J P [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

1953-07-01

Geiger Muller counters present a lake of efficiency of some per cent, for the {gamma} radiations. In the region 0,3 - 1 MeV, a substantial growth of their output can be obtained by a special construction of their cathode. In accordance with previous works, we constructed some counter of formed cathode by a pleated copper wire fencing covered of Bi by electrolysis. The successive modifications brought to a cylindrical conventional cathode in sheet metal of copper, that succeeds to this type of cathode, drive to an improvement of the output. (M.B.) [French] Les compteurs de Geiger Muller presentent une efficacite assez faible de l'ordre de quelques pour cent, pour les rayonnements {gamma}. Dans la region 0,3 - 1 MeV, un accroissement substantiel de leur rendement peut etre obtenu par une construction speciale de leur cathode. Conformement a des travaux anterieurs, nous avons construit des compteurs a cathode formee par un grillage de cuivre plisse recouvert de Bi par electrolyse. Les modifications successives apportees a une cathode conventionnelle cylindrique en tole de cuivre, qui aboutissent a ce type de cathode, conduisent a une amelioration du rendement. (M.B.)

Investigation of photon counting pixel detectors for X-ray spectroscopy and imaging

Energy Technology Data Exchange (ETDEWEB)

Talla, Patrick Takoukam

2011-04-07

The Medipix2 and Medipix3 detectors are hybrid pixelated photon counting detectors with a pixel pitch of 55 {mu}m. The sensor material used in this thesis was silicon. Because of their small pixel size they suffer from charge sharing i.e. an incoming photon can be registered by more than one pixel. In order to correct for charge sharing due to lateral diffusion of charge carriers, the Medipix3 detector was developed: with its Charge Summing Mode, the charge collected in a cluster of 2 x 2 pixel is added up and attributed to only one pixel whose counter is incremented. The adjustable threshold of the detectors allows to count the photons and to gain information on their energy. The main purposes of the thesis are to investigate spectral and imaging properties of pixelated photon counting detectors from the Medipix family such as Medipix2 and Medipix3. The investigations are based on simulations and measurements. In order to investigate the spectral properties of the detectors measurements were performed using fluorescence lines of materials such as molybdenum, silver but also some radioactive sources such as Am-241 or Cd-109. From the measured data, parameters like the threshold dispersion and the gain variation from pixel-to-pixel were extracted and used as input in the Monte Carlo code ROSI to model the responses of the detector to monoenergetic photons. The measured data are well described by the simulations for Medipix2 and for Medipix3 operating in Charge Summing Mode. Due to charge sharing and due to the energy dependence of attenuation processes in silicon and to Compton scattering the incoming and the measured spectrum differ substantially from each other. Since the responses to monoenergetic photons are known, a deconvolution was performed to determine the true incoming spectrum. Several direct and iterative methods were successfully applied on measured and simulated data of an X-ray tube and radioactive sources. The knowledge of the X-ray spectrum is

Investigation of photon counting pixel detectors for X-ray spectroscopy and imaging

International Nuclear Information System (INIS)

Talla, Patrick Takoukam

2011-01-01

The Medipix2 and Medipix3 detectors are hybrid pixelated photon counting detectors with a pixel pitch of 55 μm. The sensor material used in this thesis was silicon. Because of their small pixel size they suffer from charge sharing i.e. an incoming photon can be registered by more than one pixel. In order to correct for charge sharing due to lateral diffusion of charge carriers, the Medipix3 detector was developed: with its Charge Summing Mode, the charge collected in a cluster of 2 x 2 pixel is added up and attributed to only one pixel whose counter is incremented. The adjustable threshold of the detectors allows to count the photons and to gain information on their energy. The main purposes of the thesis are to investigate spectral and imaging properties of pixelated photon counting detectors from the Medipix family such as Medipix2 and Medipix3. The investigations are based on simulations and measurements. In order to investigate the spectral properties of the detectors measurements were performed using fluorescence lines of materials such as molybdenum, silver but also some radioactive sources such as Am-241 or Cd-109. From the measured data, parameters like the threshold dispersion and the gain variation from pixel-to-pixel were extracted and used as input in the Monte Carlo code ROSI to model the responses of the detector to monoenergetic photons. The measured data are well described by the simulations for Medipix2 and for Medipix3 operating in Charge Summing Mode. Due to charge sharing and due to the energy dependence of attenuation processes in silicon and to Compton scattering the incoming and the measured spectrum differ substantially from each other. Since the responses to monoenergetic photons are known, a deconvolution was performed to determine the true incoming spectrum. Several direct and iterative methods were successfully applied on measured and simulated data of an X-ray tube and radioactive sources. The knowledge of the X-ray spectrum is

Advances in Multi-Pixel Photon Counter technology: First characterization results

Energy Technology Data Exchange (ETDEWEB)

Bonanno, G., E-mail: gbonanno@oact.inaf.it [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Marano, D.; Romeo, G.; Garozzo, S.; Grillo, A.; Timpanaro, M.C. [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Catalano, O.; Giarrusso, S.; Impiombato, D.; La Rosa, G.; Sottile, G. [INAF, Istituto di Astrofisica Spaziale e Fisica cosmica di Palermo, Via U. La Malfa 153, I-90146 Palermo Italy (Italy)

2016-01-11

Due to the recent advances in silicon photomultiplier technology, new types of Silicon Photomultiplier (SiPM), also named Multi-Pixel Photon Counter (MPPC) detectors have become recently available, demonstrating superior performance in terms of their most important electrical and optical parameters. This paper presents the latest characterization results of the novel Low Cross-Talk (LCT) MPPC families from Hamamatsu, where a noticeable fill-factor enhancement and cross-talk reduction is achieved. In addition, the newly adopted resin coating has been proven to yield improved photon detection capabilities in the 280–320 nm spectral range, making the new LCT MPPCs particularly suitable for emerging applications like Cherenkov Telescope Array, and Astroparticle Physics.

Dual-mode optical microscope based on single-pixel imaging

Science.gov (United States)

Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

2016-07-01

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

Geiger-Mueller counter for mixed neutron-gamma beam dosimetry

International Nuclear Information System (INIS)

McDonald, J.C.; Ma, I.-C.

1978-01-01

A Geiger-Mueller (G-M) dosimeter has been constructed and employed to measure the gamma-ray component of absorbed dose in a cyclotron produced fast neutron field. This instrument is waterproof for measurements in a liquid medium, and read-out is accompanied with any standard scaler. (Auth.)

Pixel array detector for X-ray free electron laser experiments

Energy Technology Data Exchange (ETDEWEB)

Philipp, Hugh T., E-mail: htp2@cornell.edu [Department of Physics, Laboratory of Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Hromalik, Marianne [Electrical and Computer Engineering, SUNY Oswego, Oswego, NY 13126 (United States); Tate, Mark; Koerner, Lucas [Department of Physics, Laboratory of Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M. [Department of Physics, Laboratory of Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Wilson Laboratory, Cornell University, CHESS, Ithaca, NY 14853 (United States)

2011-09-01

X-ray free electron lasers (XFELs) promise to revolutionize X-ray science with extremely high peak brilliances and femtosecond X-ray pulses. This will require novel detectors to fully realize the potential of these new sources. There are many current detector development projects aimed at the many challenges of meeting the XFEL requirements . This paper describes a pixel array detector (PAD) that has been developed for the Coherent X-ray Imaging experiment at the Linac Coherent Light Source (LCLS) at the SLAC National Laboratory . The detector features 14-bit in-pixel digitization; a 2-level in-pixel gain setting that can be used to make an arbitrary 2-D gain pattern that is adaptable to a particular experiment; the ability to handle instantaneous X-ray flux rates of 10{sup 17} photons per second; and continuous frames rates in excess of 120 Hz. The detector uses direct detection of X-rays in a silicon diode. The charge produced by the diode is integrated in a pixilated application specific integrated circuit (ASIC) which digitizes collected holes with single X-ray photon capability. Each ASIC is 194x185 pixels, each pixel is 110{mu}mx110{mu}m on a side. Each pixel can detect up to 2500 X-rays per frame in low-gain mode, yet easily detects single photons at high-gain. Cooled, single-chip detectors have been built and meet all the required specifications. SLAC National Laboratory is engaged in constructing a tiled, multi-chip 1516x1516 pixel detector.

Super-Gaussian, super-diffusive transport of multi-mode active matter

OpenAIRE

Hahn, Seungsoo; Song, Sanggeun; Kim, Dae Hyun; Yang, Gil-Suk; Lee, Kang Taek; Sung, Jaeyoung

2017-01-01

Living cells exhibit multi-mode transport that switches between an active, self-propelled motion and a seemingly passive, random motion. Cellular decision-making over transport mode switching is a stochastic process that depends on the dynamics of the intracellular chemical network regulating the cell migration process. Here, we propose a theory and an exactly solvable model of multi-mode active matter. Our exact model study shows that the reversible transition between a passive mode and an a...

Multi-longitudinal-mode micro-laser model

Science.gov (United States)

Staliunas, Kestutis

2017-10-01

We derive a convenient model for broad aperture micro-lasers, such as microchip lasers, broad area semiconductor lasers, or VCSELs, taking into account several longitudinal mode families. We provide linear stability analysis, and show characteristic spatio-temporal dynamics in such multi-longitudinal mode laser models. Moreover, we derive the coupled mode model in the presence of intracavity refraction index modulation (intracavity photonic crystal). Contribution to the Topical Issue "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.

Geiger-Muller with a mica window halogen quenched counters aspects

International Nuclear Information System (INIS)

Gorski, M.S.; Bruzinga, W.A.

1990-09-01

We present the development of a model of a Geiger-Muller with likeness the model ZP 1410 Phillips. The prototype has a cylindrical shape with 37mm of effective length and a mica window of 1,5 to 2,0mg/cm sup(2) thickness with a useful diam of 19,8mm. For the window preparation and special cutting technique was developed Basically two types of quenching agents, bromine and chlorine were studied. Due to the high corrosive nature of these gases, we work with treatment of surface of the cathode through electropolishment, chemical passiveness, hard chrome and nickel coating. Out main objective was to get a Geiger-Muller detector with an operational plateau over 200V, working voltage above 600V and a sensivity of 320 counts/sec at 10 sup(-1) m Gy/h. (author)

Squeezing in multi-mode nonlinear optical state truncation

International Nuclear Information System (INIS)

Said, R.S.; Wahiddin, M.R.B.; Umarov, B.A.

2007-01-01

In this Letter, we show that multi-mode qubit states produced via nonlinear optical state truncation driven by classical external pumpings exhibit squeezing condition. We restrict our discussions to the two- and three-mode cases

Geiger-Muller (GM) counters. Associated circuits and counting techniques; Les compteurs de Geiger-Muller (GM). Les circuits associes et techniques de comptage

Energy Technology Data Exchange (ETDEWEB)

Benoit, A.; Picard, E. [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay (France)

1954-07-01

This article presents the Geiger-Muller counters which present the great benefit of being simple and steady in comparison with other known sensors. The authors propose an overview of problems related to the use of Geiger-Muller counters (GM counters). They first describe their operation (discharge initiation, discharge propagation, collection of positive ions and current in the counter). They discuss their limitations which are related to the migration delay of primary electrons and positive ions. They describe the operation circuit for counters with organic vapour, and for counters associated with counters using halogens. They address the main properties of GM counters, and the different factors to be taken into account when using them to count radioactive sources. The main types of GM counters are then described (they are used to measure different types of radiation). Measurement techniques are discussed for beta radiation (relationship between the number of disintegrations and the noticed counting rate, case of backscattering, absorption and diffusion in the counter window and in the air, influence of absorption and backscattering in the source), for alpha radiation, and for gamma radiation.

Multi-mode operations for on-line uninterruptible power supply

DEFF Research Database (Denmark)

Lu, Jinghang; Savaghebi, Mehdi; Guan, Yajuan

2018-01-01

In this paper, the multi-mode operation of the on-line UPS system is investigated and corresponding control strategies are proposed. The proposed control strategies are able to achieve the seamless transition in traditional normal mode, PV-aided normal mode, enhanced eco-mode and burn-in test mod...

Software programmable multi-mode interface for nuclear-medical imaging

International Nuclear Information System (INIS)

Zubal, I.G.; Rowe, R.W.; Bizais, Y.J.C.; Bennett, G.W.; Brill, A.B.

1982-01-01

An innovative multi-port interface allows gamma camera events (spatial coordinates and energy) to be acquired concurrently with a sampling of physiological patient data. The versatility of the interface permits all conventional static, dynamic, and tomographic imaging modes, in addition to multi-hole coded aperture acquisition. The acquired list mode data may be analyzed or gated on the basis of various camera, isotopic, or physiological parameters

Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

Science.gov (United States)

Xu, Man; Ou, Hai; Chen, Jun; Wang, Kai

2015-08-01

Since it first appeared in iPhone 5S in 2013, fingerprint identification (ID) has rapidly gained popularity among consumers. Current fingerprint-enabled smartphones unanimously consists of a discrete sensor to perform fingerprint ID. This architecture not only incurs higher material and manufacturing cost, but also provides only static identification and limited authentication. Hence as the demand for a thinner, lighter, and more secure handset grows, we propose a novel pixel architecture that is a photosensitive device embedded in a display pixel and detects the reflected light from the finger touch for high resolution, high fidelity and dynamic biometrics. To this purpose, an amorphous silicon (a-Si:H) dual-gate photo TFT working in both fingerprint-imaging mode and display-driving mode will be developed.

Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon

Science.gov (United States)

Di Giovanni, A.

2018-03-01

This work concerned the preliminary tests and characterization of a cryogenic preamplifier board for an array made of 16 S13370-3050CN (VUV4 family) Multi-Pixel Photon Counters manufactured by Hamamatsu and operated at liquid xenon temperature. The proposed prototype is based on the use of the Analog Devices AD8011 current feedback operational amplifier. The detector allows for single photon detection, making this device a promising choice for the future generation of neutrino and dark matter detectors based on liquid xenon targets.

TeraSCREEN: multi-frequency multi-mode Terahertz screening for border checks

Science.gov (United States)

Alexander, Naomi E.; Alderman, Byron; Allona, Fernando; Frijlink, Peter; Gonzalo, Ramón; Hägelen, Manfred; Ibáñez, Asier; Krozer, Viktor; Langford, Marian L.; Limiti, Ernesto; Platt, Duncan; Schikora, Marek; Wang, Hui; Weber, Marc Andree

2014-06-01

The challenge for any security screening system is to identify potentially harmful objects such as weapons and explosives concealed under clothing. Classical border and security checkpoints are no longer capable of fulfilling the demands of today's ever growing security requirements, especially with respect to the high throughput generally required which entails a high detection rate of threat material and a low false alarm rate. TeraSCREEN proposes to develop an innovative concept of multi-frequency multi-mode Terahertz and millimeter-wave detection with new automatic detection and classification functionalities. The system developed will demonstrate, at a live control point, the safe automatic detection and classification of objects concealed under clothing, whilst respecting privacy and increasing current throughput rates. This innovative screening system will combine multi-frequency, multi-mode images taken by passive and active subsystems which will scan the subjects and obtain complementary spatial and spectral information, thus allowing for automatic threat recognition. The TeraSCREEN project, which will run from 2013 to 2016, has received funding from the European Union's Seventh Framework Programme under the Security Call. This paper will describe the project objectives and approach.

Entanglement purification of multi-mode quantum states

International Nuclear Information System (INIS)

Clausen, J; Knoell, L; Welsch, D-G

2003-01-01

An iterative random procedure is considered allowing entanglement purification of a class of multi-mode quantum states. In certain cases, complete purification may be achieved using only a single signal state preparation. A physical implementation based on beam splitter arrays and non-linear elements is suggested. The influence of loss is analysed in the example of purification of entangled N-mode coherent states

Pixel readout ASIC for an APD based 2D X-ray hybrid pixel detector with sub-nanosecond resolution

Energy Technology Data Exchange (ETDEWEB)

Thil, Ch., E-mail: christophe.thil@ziti.uni-heidelberg.d [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Baron, A.Q.R. [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Fajardo, P. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France); Fischer, P. [Heidelberg University, Institute of Computer Engineering, B6, 26, 68161 Mannheim (Germany); Graafsma, H. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Rueffer, R. [ESRF, Polygone Scientifique Louis Neel, 6, rue Jules Horowitz, 38000 Grenoble (France)

2011-02-01

The fast response and the short recovery time of avalanche photodiodes (APDs) in linear mode make those devices ideal for direct X-ray detection in applications requiring high time resolution or counting rate. In order to provide position sensitivity, the XNAP project aims at creating a hybrid pixel detector with nanosecond time resolution based on a monolithic APD sensor array with 32 x32 pixels covering about 1 cm{sup 2} active area. The readout is implemented in a pixelated front-end ASIC suited for the readout of such arrays, matched to pixels of 280{mu}mx280{mu}m size. Every single channel features a fast transimpedance amplifier, a discriminator with locally adjustable threshold and two counters with high dynamic range and counting speed able to accumulate X-ray hits with no readout dead time. Additionally, the detector can be operated in list mode by time-stamping every single event with sub-nanosecond resolution. In a first phase of the project, a 4x4 pixel test module is built to validate the conceptual design of the detector. The XNAP project is briefly presented and the performance of the readout ASIC is discussed.

Pixel readout ASIC for an APD based 2D X-ray hybrid pixel detector with sub-nanosecond resolution

International Nuclear Information System (INIS)

Thil, Ch.; Baron, A.Q.R.; Fajardo, P.; Fischer, P.; Graafsma, H.; Rueffer, R.

2011-01-01

The fast response and the short recovery time of avalanche photodiodes (APDs) in linear mode make those devices ideal for direct X-ray detection in applications requiring high time resolution or counting rate. In order to provide position sensitivity, the XNAP project aims at creating a hybrid pixel detector with nanosecond time resolution based on a monolithic APD sensor array with 32 x32 pixels covering about 1 cm 2 active area. The readout is implemented in a pixelated front-end ASIC suited for the readout of such arrays, matched to pixels of 280μmx280μm size. Every single channel features a fast transimpedance amplifier, a discriminator with locally adjustable threshold and two counters with high dynamic range and counting speed able to accumulate X-ray hits with no readout dead time. Additionally, the detector can be operated in list mode by time-stamping every single event with sub-nanosecond resolution. In a first phase of the project, a 4x4 pixel test module is built to validate the conceptual design of the detector. The XNAP project is briefly presented and the performance of the readout ASIC is discussed.

Bio-inspired multi-mode optic flow sensors for micro air vehicles

Science.gov (United States)

Park, Seokjun; Choi, Jaehyuk; Cho, Jihyun; Yoon, Euisik

2013-06-01

Monitoring wide-field surrounding information is essential for vision-based autonomous navigation in micro-air-vehicles (MAV). Our image-cube (iCube) module, which consists of multiple sensors that are facing different angles in 3-D space, can be applied to the wide-field of view optic flows estimation (μ-Compound eyes) and to attitude control (μ- Ocelli) in the Micro Autonomous Systems and Technology (MAST) platforms. In this paper, we report an analog/digital (A/D) mixed-mode optic-flow sensor, which generates both optic flows and normal images in different modes for μ- Compound eyes and μ-Ocelli applications. The sensor employs a time-stamp based optic flow algorithm which is modified from the conventional EMD (Elementary Motion Detector) algorithm to give an optimum partitioning of hardware blocks in analog and digital domains as well as adequate allocation of pixel-level, column-parallel, and chip-level signal processing. Temporal filtering, which may require huge hardware resources if implemented in digital domain, is remained in a pixel-level analog processing unit. The rest of the blocks, including feature detection and timestamp latching, are implemented using digital circuits in a column-parallel processing unit. Finally, time-stamp information is decoded into velocity from look-up tables, multiplications, and simple subtraction circuits in a chip-level processing unit, thus significantly reducing core digital processing power consumption. In the normal image mode, the sensor generates 8-b digital images using single slope ADCs in the column unit. In the optic flow mode, the sensor estimates 8-b 1-D optic flows from the integrated mixed-mode algorithm core and 2-D optic flows with an external timestamp processing, respectively.

Characterization of Ir/Au pixel TES

International Nuclear Information System (INIS)

Kunieda, Y.; Takahashi, H.; Zen, N.; Damayanthi, R.M.T.; Mori, F.; Fujita, K.; Nakazawa, M.; Fukuda, D.; Ohkubo, M.

2006-01-01

Signal shapes and noise characteristics of an asymmetrical ten-pixel Ir/Au-TES have been studied. The asymmetric design may be effective to realize an imaging spectrometer. Distinct two exponential decays observed for X-ray events are consistent with a two-step R-T curve. A theoretical thermal model for noise in multi-pixel devices reasonably explains the experimental data

Adaptive fuzzy sliding-mode control for multi-input multi-output chaotic systems

International Nuclear Information System (INIS)

Poursamad, Amir; Markazi, Amir H.D.

2009-01-01

This paper describes an adaptive fuzzy sliding-mode control algorithm for controlling unknown or uncertain, multi-input multi-output (MIMO), possibly chaotic, dynamical systems. The control approach encompasses a fuzzy system and a robust controller. The fuzzy system is designed to mimic an ideal sliding-mode controller, and the robust controller compensates the difference between the fuzzy controller and the ideal one. The parameters of the fuzzy system, as well as the uncertainty bound of the robust controller, are tuned adaptively. The adaptive laws are derived in the Lyapunov sense to guarantee the asymptotic stability and tracking of the controlled system. The effectiveness of the proposed method is shown by applying it to some well-known chaotic systems.

Multi-Mode Cavity Accelerator Structure

Energy Technology Data Exchange (ETDEWEB)

Jiang, Yong [Yale Univ., New Haven, CT (United States); Hirshfield, Jay Leonard [Omega-P R& D, Inc., New Haven, CT (United States)

2016-11-10

This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10^-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field E_sur^max< 260 MV/m and pulsed surface heating ΔT^max< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

Multi-Mode Cavity Accelerator Structure

International Nuclear Information System (INIS)

Jiang, Yong; Hirshfield, Jay Leonard

2016-01-01

This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10"-"7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise Δ T. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field E_s_u_r"m"a"x< 260 MV/m and pulsed surface heating Δ T"m"a"x< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power - as compared with operation at the same acceleration gradient using only the fundamental mode.

Simulation study of pixel detector charge digitization

Science.gov (United States)

Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

2017-01-01

Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

Scaling Fiber Lasers to Large Mode Area: An Investigation of Passive Mode-Locking Using a Multi-Mode Fiber.

Science.gov (United States)

Ding, Edwin; Lefrancois, Simon; Kutz, Jose Nathan; Wise, Frank W

2011-01-01

The mode-locking of dissipative soliton fiber lasers using large mode area fiber supporting multiple transverse modes is studied experimentally and theoretically. The averaged mode-locking dynamics in a multi-mode fiber are studied using a distributed model. The co-propagation of multiple transverse modes is governed by a system of coupled Ginzburg-Landau equations. Simulations show that stable and robust mode-locked pulses can be produced. However, the mode-locking can be destabilized by excessive higher-order mode content. Experiments using large core step-index fiber, photonic crystal fiber, and chirally-coupled core fiber show that mode-locking can be significantly disturbed in the presence of higher-order modes, resulting in lower maximum single-pulse energies. In practice, spatial mode content must be carefully controlled to achieve full pulse energy scaling. This paper demonstrates that mode-locking performance is very sensitive to the presence of multiple waveguide modes when compared to systems such as amplifiers and continuous-wave lasers.

Dynamic feedback for multi-mode plasma instabilities

International Nuclear Information System (INIS)

Sen, A.K.

1978-01-01

Constant feedback, which has been used exclusively, fails to stabilize more than one mode of a plasma instability. It is shown that a suitable dynamic or frequency-dependent feedback can stabilize all modes. Methods are developed in which such a feedback structure can be chosen in terms of its poles and zeros in relation to those of the plasma transfer function in the complex frequency plane. The synthesis procedure for such a feedback structure, in the form of an integrated electronic circuit is also discussed. As an example, a dynamic feedback for multi-mode stabilization of a collisional drift wave instability is developed in detail. (author)

Compressive multi-mode superresolution display

KAUST Repository

Heide, Felix; Gregson, James; Wetzstein, Gordon; Raskar, Ramesh D.; Heidrich, Wolfgang

2014-01-01

consists of readily-available components and is driven by a novel splitting algorithm that computes the pixel states from a target high-resolution image. In effect, the display pixels present a compressed representation of the target image that is perceived

A 30 ps Timing Resolution for Single Photons with Multi-pixel Burle MCP-PMT

Energy Technology Data Exchange (ETDEWEB)

Va' vra, J.; Benitez, J.; Coleman, J.; Leith, D.W.G.S.; Mazaheri, G.; Ratcliff, B.; Schwiening, J.; /SLAC

2006-07-05

We have achieved {approx}30 psec single-photoelectron and {approx}12ps for multi-photoelectron timing resolution with a new 64 pixel Burle MCP-PMT with 10 micron microchannel holes. We have also demonstrated that this detector works in a magnetic field of 15kG, and achieved a single-photoelectron timing resolution of better than 60 psec. The study is relevant for a new focusing DIRC RICH detector for particle identification at future Colliders such as the super B-factory or ILC, and for future TOF techniques. This study shows that a highly pixilated MCP-PMT can deliver excellent timing resolution.

An Adaptive Large Neighborhood Search Algorithm for the Multi-mode RCPSP

DEFF Research Database (Denmark)

Muller, Laurent Flindt

We present an Adaptive Large Neighborhood Search algorithm for the Multi-mode Resource-Constrained Project Scheduling Problem (MRCPSP). We incorporate techniques for deriving additional precedence relations and propose a new method, so-called mode-diminution, for removing modes during execution...

CMOS VLSI Active-Pixel Sensor for Tracking

Science.gov (United States)

Pain, Bedabrata; Sun, Chao; Yang, Guang; Heynssens, Julie

2004-01-01

An architecture for a proposed active-pixel sensor (APS) and a design to implement the architecture in a complementary metal oxide semiconductor (CMOS) very-large-scale integrated (VLSI) circuit provide for some advanced features that are expected to be especially desirable for tracking pointlike features of stars. The architecture would also make this APS suitable for robotic- vision and general pointing and tracking applications. CMOS imagers in general are well suited for pointing and tracking because they can be configured for random access to selected pixels and to provide readout from windows of interest within their fields of view. However, until now, the architectures of CMOS imagers have not supported multiwindow operation or low-noise data collection. Moreover, smearing and motion artifacts in collected images have made prior CMOS imagers unsuitable for tracking applications. The proposed CMOS imager (see figure) would include an array of 1,024 by 1,024 pixels containing high-performance photodiode-based APS circuitry. The pixel pitch would be 9 m. The operations of the pixel circuits would be sequenced and otherwise controlled by an on-chip timing and control block, which would enable the collection of image data, during a single frame period, from either the full frame (that is, all 1,024 1,024 pixels) or from within as many as 8 different arbitrarily placed windows as large as 8 by 8 pixels each. A typical prior CMOS APS operates in a row-at-a-time ( grolling-shutter h) readout mode, which gives rise to exposure skew. In contrast, the proposed APS would operate in a sample-first/readlater mode, suppressing rolling-shutter effects. In this mode, the analog readout signals from the pixels corresponding to the windows of the interest (which windows, in the star-tracking application, would presumably contain guide stars) would be sampled rapidly by routing them through a programmable diagonal switch array to an on-chip parallel analog memory array. The

Characterization and simulation of the response of Multi-Pixel Photon Counters to low light levels

Energy Technology Data Exchange (ETDEWEB)

Vacheret, A. [Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Barker, G.J. [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Dziewiecki, M. [Institute of Radioelectronics, Warsaw University of Technology, 15/19 Nowowiejska St., 00-665 Warsaw (Poland); Guzowski, P. [Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Haigh, M.D. [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Hartfiel, B. [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States); Izmaylov, A. [Institute for Nuclear Research RAS, 60 October Revolution Pr. 7A, 117312 Moscow (Russian Federation); Johnston, W. [Department of Physics, Colorado State University, Fort Collins, CO 80523 (United States); Khabibullin, M.; Khotjantsev, A.; Kudenko, Yu. [Institute for Nuclear Research RAS, 60 October Revolution Pr. 7A, 117312 Moscow (Russian Federation); Kurjata, R. [Institute of Radioelectronics, Warsaw University of Technology, 15/19 Nowowiejska St., 00-665 Warsaw (Poland); Kutter, T. [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States); Lindner, T. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, Canada, BC V6T 1Z1 (Canada); Masliah, P. [Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Marzec, J. [Institute of Radioelectronics, Warsaw University of Technology, 15/19 Nowowiejska St., 00-665 Warsaw (Poland); Mineev, O.; Musienko, Yu. [Institute for Nuclear Research RAS, 60 October Revolution Pr. 7A, 117312 Moscow (Russian Federation); and others

2011-11-11

The calorimeter, range detector and active target elements of the T2K near detectors rely on the Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) to detect scintillation light produced by charged particles. Detailed measurements of the MPPC gain, afterpulsing, crosstalk, dark noise, and photon detection efficiency for low light levels are reported. In order to account for the impact of the MPPC behavior on T2K physics observables, a simulation program has been developed based on these measurements. The simulation is used to predict the energy resolution of the detector.

Characterization and simulation of the response of Multi-Pixel Photon Counters to low light levels

International Nuclear Information System (INIS)

Vacheret, A.; Barker, G.J.; Dziewiecki, M.; Guzowski, P.; Haigh, M.D.; Hartfiel, B.; Izmaylov, A.; Johnston, W.; Khabibullin, M.; Khotjantsev, A.; Kudenko, Yu.; Kurjata, R.; Kutter, T.; Lindner, T.; Masliah, P.; Marzec, J.; Mineev, O.; Musienko, Yu.

2011-01-01

The calorimeter, range detector and active target elements of the T2K near detectors rely on the Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) to detect scintillation light produced by charged particles. Detailed measurements of the MPPC gain, afterpulsing, crosstalk, dark noise, and photon detection efficiency for low light levels are reported. In order to account for the impact of the MPPC behavior on T2K physics observables, a simulation program has been developed based on these measurements. The simulation is used to predict the energy resolution of the detector.

Silicon photomultipliers for scintillating trackers

Energy Technology Data Exchange (ETDEWEB)

Rabaioli, S., E-mail: simone.rabaioli@gmail.com [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Berra, A.; Bolognini, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Bonvicini, V. [INFN sezione di Trieste (Italy); Bosisio, L. [Universita degli Studi di Trieste and INFN sezione di Trieste (Italy); Ciano, S.; Iugovaz, D. [INFN sezione di Trieste (Italy); Lietti, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Penzo, A. [INFN sezione di Trieste (Italy); Prest, M. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Rashevskaya, I.; Reia, S. [INFN sezione di Trieste (Italy); Stoppani, L. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Vallazza, E. [INFN sezione di Trieste (Italy)

2012-12-11

In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain ({approx}10{sup 6}). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

Silicon photomultipliers for scintillating trackers

Science.gov (United States)

Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

2012-12-01

In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

Application of a background-compensated Geiger-Mueller counter to a survey meter

International Nuclear Information System (INIS)

Mori, C.; Kumanomido, H.; Watanabe, T.

1984-01-01

A background-compensated Geiger-Mueller counter was used as a probe for a GM survey meter to obtain a net count rate of β-rays from a radioactive source in a quick survey. Although a background counting ratio between the two parts in the counter, front and rear, varied somewhat depending on the incident direction of background γ-rays, it was possible to compensate the background counts by subtracting a part of the rear counts, which were background counts, from the front counts, which contained β-ray counts and background counts. Undesirable small pulses generated during the recovering time after a full Geiger discharge were eliminated by an anticoincidence gating method. The survey meter with this counter and a differential ratemeter is useful for obtaining a net count rate of β-rays emitted from a surface radioactive-contamination or from a source being put near the window of the counter with nearly the same accuracy in half the measuring time as compared with conventional GM counters. (orig.)

Multi-Objective Optimization Considering Battery Degradation for a Multi-Mode Power-Split Electric Vehicle

Directory of Open Access Journals (Sweden)

Xuerui Ma

2017-07-01

Full Text Available A multi-mode power-split (MMPS hybrid electric vehicle (HEV has two planetary gearsets and clutches/grounds which results in several operation modes with enhanced electric drive capability and better fuel economy. Basically, the battery storage system is involved in different operation modes to satisfy the power demand and minimize the fuel consumption, whereas the complicated operation modes with frequent charging/discharging will absolutely influence the battery life because of degradation. In this paper, firstly, we introduce the solid electrolyte interface (SEI film growth model based on the previous study of the battery degradation principles and was verified according to the test data. We consider both the fuel economy and battery degradation as a multi-objective problem for MMPS HEV by normalization with a weighting factor. An instantaneous optimization is implemented based on the equivalent fuel consumption concept. Then the control strategy is implemented on a simulation framework integrating the MMPS powertrain model and the SEI film growth map model over some typical driving cycles, such as New European Driving Cycle (NEDC and Urban Dynamometer Driving Schedule (UDDS. Finally, the result demonstrates that these two objectives are conflicting and the trade-off reduces the battery degradation with fuel sacrifice. Additionally, the analysis reveals how the mode selection will reflect the battery degradation.

General Roy S. Geiger, USMC: Marine Aviator, Joint Force Commander

Science.gov (United States)

2007-06-01

This is a strong assertion, given the significant and better-known contributions of great Marines such as John Lejeune, Smedley Butler, Alexander...While stationed in Panama, Geiger made a favorable impression on Major Smedley Butler, who later earned the Medal of Honor twice and became a...fifth Naval Aviator. 43 Johnson, 5. 44 Robert Sherrod, History of Marine Corps Aviation in World War II (Baltimore, MD: The Nautical and Aviation

Multi-operational tuneable Q-switched mode-locking Er fibre laser

Science.gov (United States)

Qamar, F. Z.

2018-01-01

A wavelength-spacing tuneable, Q-switched mode-locking (QML) erbium-doped fibre laser based on non-linear polarization rotation controlled by four waveplates and a cube polarizer is proposed. A mode-locked pulse train using two quarter-wave plates and a half-wave plate (HWP) is obtained first, and then an extra HWP is inserted into the cavity to produce different operation regimes. The evolutions of temporal and spectral dynamics with different orientation angles of the extra HWP are investigated. A fully modulated stable QML pulse train is observed experimentally. This is, to the author’s best knowledge, the first experimental work reporting QML operation without adding an extra saturable absorber inside the laser cavity. Multi-wavelength pulse laser operation, multi-pulse train continuous-wave mode-locking operation and pulse-splitting operations are also reported at certain HWP angles. The observed operational dynamics are interpreted as a mutual interaction of dispersion, non-linear effect and insertion loss. This work provides a new mechanism for fabricating cheap tuneable multi-wavelength lasers with QML pulses.

A novel gamma-ray detector with submillimeter resolutions using a monolithic MPPC array with pixelized Ce:LYSO and Ce:GGAG crystals

Energy Technology Data Exchange (ETDEWEB)

Kato, T., E-mail: katou.frme.8180@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan); Ikeda, H. [ISAS/JAXA, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Yamamoto, S. [Kobe City College of Technology, 8-3, Gakuenhigashimati, Nishi-ku, Kobe-shi, Hyougo 651-2194 (Japan); Kamada, K. [Materials Research Laboratory, Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)

2013-01-21

We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm{sup 2} and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×10{sup 5} at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu,Y){sub 2}(SiO{sub 4})O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm{sup 3} crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd{sub 3}Ga{sub 3}Al{sub 2}O{sub 12} (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm{sup 2} pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a {sup 137}Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET). -- Highlights: ► We developed a newly designed large-area monolithic MPPC array. ► We obtained fine gain uniformity, and good energy and time resolutions when coupled to the LYSO scintillator. ► We fabricated gamma-ray camera consisting of the MPPC array and submillimeter pixelized LYSO and GGAG scintillators. ► In

A robo-pigeon based on an innovative multi-mode telestimulation system.

Science.gov (United States)

Yang, Junqing; Huai, Ruituo; Wang, Hui; Lv, Changzhi; Su, Xuecheng

2015-01-01

In this paper, we describe a new multi-mode telestimulation system for brain-microstimulation for the navigation of a robo-pigeon, a new type of bio-robot based on Brain-Computer Interface (BCI) techniques. The multi-mode telestimulation system overcomes neuron adaptation that was a key shortcoming of the previous single-mode stimulation by the use of non-steady TTL biphasic pulses accomplished by randomly alternating pulse modes. To improve efficiency, a new behavior model ("virtual fear") is proposed and applied to the robo-pigeon. Unlike the previous "virtual reward" model, the "virtual fear" behavior model does not require special training. The performance and effectiveness of the system to alleviate the adaptation of neurons was verified by a robo-pigeon navigation test, simultaneously confirming the practicality of the "virtual fear" behavioral model.

18k Channels single photon counting readout circuit for hybrid pixel detector

International Nuclear Information System (INIS)

Maj, P.; Grybos, P.; Szczygiel, R.; Zoladz, M.; Sakumura, T.; Tsuji, Y.

2013-01-01

We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm×20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96×192 pixels with 100 μm×100 μm pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 μW/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 μV/e − and the equivalent noise charge is 168 e − rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

18k Channels single photon counting readout circuit for hybrid pixel detector

Energy Technology Data Exchange (ETDEWEB)

Maj, P., E-mail: piotr.maj@agh.edu.pl [AGH University of Science and Technology, Department of Measurements and Electronics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Grybos, P.; Szczygiel, R.; Zoladz, M. [AGH University of Science and Technology, Department of Measurements and Electronics, Al. Mickiewicza 30, 30-059 Krakow (Poland); Sakumura, T.; Tsuji, Y. [X-ray Analysis Division, Rigaku Corporation, Matsubara, Akishima, Tokyo 196-8666 (Japan)

2013-01-01

We have performed measurements of an integrated circuit named PXD18k designed for hybrid pixel semiconductor detectors used in X-ray imaging applications. The PXD18k integrated circuit, fabricated in CMOS 180 nm technology, has dimensions of 9.64 mm Multiplication-Sign 20 mm and contains approximately 26 million transistors. The core of the IC is a matrix of 96 Multiplication-Sign 192 pixels with 100 {mu}m Multiplication-Sign 100 {mu}m pixel size. Each pixel works in a single photon counting mode. A single pixel contains two charge sensitive amplifiers with Krummenacher feedback scheme, two shapers, two discriminators (with independent thresholds A and B) and two 16-bit ripple counters. The data are read out via eight low voltage differential signaling (LVDS) outputs with 100 Mbps rate. The power consumption is dominated by analog blocks and it is about 23 {mu}W/pixel. The effective peaking time at the discriminator input is 30 ns and is mainly determined by the time constants of the charge sensitive amplifier (CSA). The gain is equal to 42.5 {mu}V/e{sup -} and the equivalent noise charge is 168 e{sup -} rms (with bump-bonded silicon pixel detector). Thanks to the use of trim DACs in each pixel, the effective threshold spread at the discriminator input is only 1.79 mV. The dead time of the front end electronics for a standard setting is 172 ns (paralyzable model). In the standard readout mode (when the data collection time is separated from the time necessary to readout data from the chip) the PXD18k IC works with two energy thresholds per pixel. The PXD18k can also be operated in the continuous readout mode (with a zero dead time) where one can select the number of bits readout from each pixel to optimize the PXD18k frame rate. For example, for reading out 16 bits/pixel the frame rate is 2.7 kHz and for 4 bits/pixel it rises to 7.1 kHz.

A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

Energy Technology Data Exchange (ETDEWEB)

Zhang, L., E-mail: liang.zhang@iphc.cnrs.fr [School of Physics, Key Laboratory of Particle Physics and Particle Irradiation, Shandong University, 250100 Jinan (China); Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS/IN2P3/UDS, 23 rue du loess, BP 28, 67037 Strasbourg (France); Morel, F.; Hu-Guo, C.; Hu, Y. [Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS/IN2P3/UDS, 23 rue du loess, BP 28, 67037 Strasbourg (France)

2014-07-01

CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm{sup 2}. The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/−0.28 LSB and 0.29/−0.20 LSB, respectively. - Highlights: • CMOS sensor integrated with column-level ADC is proposed for ILC VTX outer layers. • A low-power and small-area column-level ADC for high frame-rate CPS is presented. • The test results demonstrate the power and area efficiency. • The architecture is suitable for the outer layer CMOS sensors.

A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

International Nuclear Information System (INIS)

Zhang, L.; Morel, F.; Hu-Guo, C.; Hu, Y.

2014-01-01

CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm 2 . The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/−0.28 LSB and 0.29/−0.20 LSB, respectively. - Highlights: • CMOS sensor integrated with column-level ADC is proposed for ILC VTX outer layers. • A low-power and small-area column-level ADC for high frame-rate CPS is presented. • The test results demonstrate the power and area efficiency. • The architecture is suitable for the outer layer CMOS sensors

Mapping Weathering and Alteration Minerals in the Comstock and Geiger Grade Areas using Visible to Thermal Infrared Airborne Remote Sensing Data

Science.gov (United States)

Vaughan, Greg R.; Calvin, Wendy M.

2005-01-01

To support research into both precious metal exploration and environmental site characterization a combination of high spatial/spectral resolution airborne visible, near infrared, short wave infrared (VNIR/SWIR) and thermal infrared (TIR) image data were acquired to remotely map hydrothermal alteration minerals around the Geiger Grade and Comstock alteration regions, and map the mineral by-products of weathered mine dumps in Virginia City. Remote sensing data from the Airborne Visible Infrared Imaging Spectrometer (AVIRIS), SpecTIR Corporation's airborne hyperspectral imager (HyperSpecTIR), the MODIS-ASTER airborne simulator (MASTER), and the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) were acquired and processed into mineral maps based on the unique spectral signatures of image pixels. VNIR/SWIR and TIR field spectrometer data were collected for both calibration and validation of the remote data sets, and field sampling, laboratory spectral analyses and XRD analyses were made to corroborate the surface mineralogy identified by spectroscopy. The resulting mineral maps show the spatial distribution of several important alteration minerals around each study area including alunite, quartz, pyrophyllite, kaolinite, montmorillonite/muscovite, and chlorite. In the Comstock region the mineral maps show acid-sulfate alteration, widespread propylitic alteration and extensive faulting that offsets the acid-sulfate areas, in contrast to the larger, dominantly acid-sulfate alteration exposed along Geiger Grade. Also, different mineral zones within the intense acid-sulfate areas were mapped. In the Virginia City historic mining district the important weathering minerals mapped include hematite, goethite, jarosite and hydrous sulfate minerals (hexahydrite, alunogen and gypsum) located on mine dumps. Sulfate minerals indicate acidic water forming in the mine dump environment. While there is not an immediate threat to the community, there are clearly sources of

A High Performance Multi-Core FPGA Implementation for 2D Pixel Clustering for the ATLAS Fast TracKer (FTK) Processor

CERN Document Server

Sotiropoulou, C-L; The ATLAS collaboration; Beretta, M; Gkaitatzis, S; Kordas, K; Nikolaidis, S; Petridou, C; Volpi, G

2014-01-01

The high performance multi-core 2D pixel clustering FPGA implementation used for the input system of the ATLAS Fast TracKer (FTK) processor is presented. The input system for the FTK processor will receive data from the Pixel and micro-strip detectors read out drivers (RODs) at 760Gbps, the full rate of level 1 triggers. Clustering is required as a method to reduce the high rate of the received data before further processing, as well as to determine the cluster centroid for obtaining obtain the best spatial measurement. Our implementation targets the pixel detectors and uses a 2D-clustering algorithm that takes advantage of a moving window technique to minimize the logic required for cluster identification. The design is fully generic and the cluster detection window size can be adjusted for optimizing the cluster identification process. Τhe implementation can be parallelized by instantiating multiple cores to identify different clusters independently thus exploiting more FPGA resources. This flexibility mak...

Compressive Video Recovery Using Block Match Multi-Frame Motion Estimation Based on Single Pixel Cameras

Directory of Open Access Journals (Sweden)

Sheng Bi

2016-03-01

Full Text Available Compressive sensing (CS theory has opened up new paths for the development of signal processing applications. Based on this theory, a novel single pixel camera architecture has been introduced to overcome the current limitations and challenges of traditional focal plane arrays. However, video quality based on this method is limited by existing acquisition and recovery methods, and the method also suffers from being time-consuming. In this paper, a multi-frame motion estimation algorithm is proposed in CS video to enhance the video quality. The proposed algorithm uses multiple frames to implement motion estimation. Experimental results show that using multi-frame motion estimation can improve the quality of recovered videos. To further reduce the motion estimation time, a block match algorithm is used to process motion estimation. Experiments demonstrate that using the block match algorithm can reduce motion estimation time by 30%.

Development of the MCM-D technique for pixel detector modules

CERN Document Server

Grah, Christian

2005-01-01

This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end ...

CMOS Active-Pixel Image Sensor With Simple Floating Gates

Science.gov (United States)

Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

1996-01-01

Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

Geiger counters of gamma rays with a bismuth cathode

International Nuclear Information System (INIS)

Meunier, R.; Legrand, J.P.

1953-01-01

Geiger Muller counters present a lake of efficiency of some per cent, for the γ radiations. In the region 0,3 - 1 MeV, a substantial growth of their output can be obtained by a special construction of their cathode. In accordance with previous works, we constructed some counter of formed cathode by a pleated copper wire fencing covered of Bi by electrolysis. The successive modifications brought to a cylindrical conventional cathode in sheet metal of copper, that succeeds to this type of cathode, drive to an improvement of the output. (M.B.) [fr

Wolfgang Geiger (17 July 1921 - 3 July 2000

Directory of Open Access Journals (Sweden)

Renata Boucher-Rodoni

2000-08-01

Full Text Available Wolfgang Geiger died on the 3rd July 2000, at the age of 79. He was born on July 17th 1921 in Biel; his mother died at his birth. His childhood was spent with his father, a well-known artist, partly in Ligerz, on Lake Biel, and partly in Porto Ronco in Ticino, on Lago Maggiore. After high school in Biel, he began his University studies, first at the Swiss Federal Institute of Technology in Zürich, then in Basel, where he studied under Professor A. Portmann. During his PhD a grant from the Janggen-Pöhn foundation enabled him to work for some months at the Institut des Pêches maritimes du Maroc, in Casablanca, with Dr. J .Furnestin. In 1953 he completed his PhD on teleost fish brain. His career as a biologist began in Bern at the Eidgenossische Inspektion für Fortwesen, Jagd und Fischerei. In 1962 he was appointed head assistant (chef des travaux at the University of Geneva, in the comparative anatomy and physiology laboratory (Dr H. J. Huggel, where he discovered the joys and the limitations of teaching. He was highly regarded as a lecturer and taught in a relaxed atmosphere of mutual respect and trust, much appreciated by his students. Professor Geiger was also the main organiser of field trips to Sète, on the French Mediterranean coast, where he was in his element living on the water. He went out on the trawlers with the students and introduced them enthusiastically to the marvels of sea fauna. He was happy during those field trips and had the knack of communicating his happiness to the students.

Investigation of single-mode and multi-mode hydromagnetic Rayleigh-Taylor instability in planar geometry

International Nuclear Information System (INIS)

Roderick, N.F.; Cochrane, K.; Douglas, M.R.

1998-01-01

Previous investigations carried out to study various methods of seeding the hydromagnetic Rayleigh-Taylor instability in magnetohydrodynamic simulations showed features similar to those seen in hydrodynamic calculations. For periodic single-mode initiations the results showed the appearance of harmonics as the single modes became nonlinear. For periodic multi-mode initiations new modes developed that indicated the presence of mode coupling. The MHD simulations used parameters of the high velocity large radius z-pinch experiments performed in the Z-accelerator at Sandia National Laboratories. The cylindrical convergent geometry and variable acceleration of these configurations made comparison with analytic, developed for planar geometry with constant acceleration, difficult. A set of calculations in planar geometry using constant current to produce acceleration and parameters characteristic of the cylindrical implosions has been performed to allow a better comparison. Results of these calculations, comparison with analytic theory, and comparison with the cylindrical configuration calculations will be discussed

The ALICE silicon pixel detector front-end and read-out electronics

CERN Document Server

Kluge, A

2006-01-01

The ALICE silicon pixel detector (SPD) comprises the two innermost barrel layers of the ALICE inner tracker system. The SPD includes 120 half staves each of which consists of a linear array of 10 ALICE pixel chips bump bonded to two silicon sensors. Each pixel chip contains 8192 active cells, so the total number of pixel cells in the SPD is ≈107. The tight material budget and the limitation in physical dimensions required by the detector design introduce new challenges for the integration of the on-detector electronics. An essential part of the half stave is a low-mass multi-layer flex that carries power, ground, and signals to the pixel chips. Each half stave is read out using a multi-chip module (MCM). The MCM contains three radiation hard ASICs and an 800 Mbit/s custom developed optical link for the data transfer between the detector and the control room. The detector components are less than 3 mm thick. The production of the half-staves and MCMs is currently under way. Test results as well as on overvie...

Selective injection locking of a multi-mode semiconductor laser to a multi-frequency reference beam

Science.gov (United States)

Pramod, Mysore Srinivas; Yang, Tao; Pandey, Kanhaiya; Giudici, Massimo; Wilkowski, David

2014-07-01

Injection locking is a well known and commonly used method for coherent light amplification. Usually injection locking is obtained on a single-mode laser injected by a single-frequency seeding beam. In this work we show that selective injection locking of a single-frequency may also be achieved on a multi-mode semiconductor laser injected by a multi-frequency seeding beam, if the slave laser provides sufficient frequency filtering. This selective injection locking condition depends critically on the frequency detuning between the free-running slave emission frequency and each injected frequency component. Stable selective injection locking to a set of three seeding components separated by 1.2 GHz is obtained. This system provides an amplification up to 37 dB of each component. This result suggests that, using distinct slave lasers for each frequency line, a set of mutually coherent high-power radiation modes can be tuned in the GHz frequency domain.

High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

Energy Technology Data Exchange (ETDEWEB)

Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

2014-08-07

The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

Optimization of orthotropic distributed-mode loudspeaker using attached masses and multi-exciters.

Science.gov (United States)

Lu, Guochao; Shen, Yong; Liu, Ziyun

2012-02-01

Based on the orthotropic model of the plate, the method to optimize the sound response of the distributed-mode loudspeaker (DML) using the attached masses and the multi-exciters has been investigated. The attached masses method will rebuild the modes distribution of the plate, based on which multi-exciter method will smooth the sound response. The results indicate that the method can be used to optimize the sound response of the DML. © 2012 Acoustical Society of America

The Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem

Directory of Open Access Journals (Sweden)

Denis Pinha

2016-11-01

Full Text Available This paper presents the formulation and solution of the Combinatorial Multi-Mode Resource Constrained Multi-Project Scheduling Problem. The focus of the proposed method is not on finding a single optimal solution, instead on presenting multiple feasible solutions, with cost and duration information to the project manager. The motivation for developing such an approach is due in part to practical situations where the definition of optimal changes on a regular basis. The proposed approach empowers the project manager to determine what is optimal, on a given day, under the current constraints, such as, change of priorities, lack of skilled worker. The proposed method utilizes a simulation approach to determine feasible solutions, under the current constraints. Resources can be non-consumable, consumable, or doubly constrained. The paper also presents a real-life case study dealing with scheduling of ship repair activities.

Dense Iterative Contextual Pixel Classification using Kriging

DEFF Research Database (Denmark)

Ganz, Melanie; Loog, Marco; Brandt, Sami

2009-01-01

have been proposed to this end, e.g., iterative contextual pixel classification, iterated conditional modes, and other approaches related to Markov random fields. A problem of these methods, however, is their computational complexity, especially when dealing with high-resolution images in which......In medical applications, segmentation has become an ever more important task. One of the competitive schemes to perform such segmentation is by means of pixel classification. Simple pixel-based classification schemes can be improved by incorporating contextual label information. Various methods...... relatively long range interactions may play a role. We propose a new method based on Kriging that makes it possible to include such long range interactions, while keeping the computations manageable when dealing with large medical images....

Pixel multiplexing technique for real-time three-dimensional-imaging laser detection and ranging system using four linear-mode avalanche photodiodes

Energy Technology Data Exchange (ETDEWEB)

Xu, Fan; Wang, Yuanqing, E-mail: yqwang@nju.edu.cn; Li, Fenfang [School of Electronic Science and Engineering, Nanjing University, Nanjing 210046 (China)

2016-03-15

The avalanche-photodiode-array (APD-array) laser detection and ranging (LADAR) system has been continually developed owing to its superiority of nonscanning, large field of view, high sensitivity, and high precision. However, how to achieve higher-efficient detection and better integration of the LADAR system for real-time three-dimensional (3D) imaging continues to be a problem. In this study, a novel LADAR system using four linear mode APDs (LmAPDs) is developed for high-efficient detection by adopting a modulation and multiplexing technique. Furthermore, an automatic control system for the array LADAR system is proposed and designed by applying the virtual instrumentation technique. The control system aims to achieve four functions: synchronization of laser emission and rotating platform, multi-channel synchronous data acquisition, real-time Ethernet upper monitoring, and real-time signal processing and 3D visualization. The structure and principle of the complete system are described in the paper. The experimental results demonstrate that the LADAR system is capable of achieving real-time 3D imaging on an omnidirectional rotating platform under the control of the virtual instrumentation system. The automatic imaging LADAR system utilized only 4 LmAPDs to achieve 256-pixel-per-frame detection with by employing 64-bit demodulator. Moreover, the lateral resolution is ∼15 cm and range accuracy is ∼4 cm root-mean-square error at a distance of ∼40 m.

Physics basis of Multi-Mode anomalous transport module

Energy Technology Data Exchange (ETDEWEB)

Rafiq, T.; Kritz, A. H.; Luo, L. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Weiland, J. [Departments of Applied Physics, Chalmers University of Technology and Euratom-VR Assoc., S41296 Gothenburg (Sweden); Pankin, A. Y. [Tech-X Corporation, Boulder, Colorado (United States)

2013-03-15

The derivation of Multi-Mode anomalous transport module version 8.1 (MMM8.1) is presented. The MMM8.1 module is advanced, relative to MMM7.1, by the inclusion of peeling modes, dependence of turbulence correlation length on flow shear, electromagnetic effects in the toroidal momentum diffusivity, and the option to compute poloidal momentum diffusivity. The MMM8.1 model includes a model for ion temperature gradient, trapped electron, kinetic ballooning, peeling, collisionless and collision dominated magnetohydrodynamics modes as well as model for electron temperature gradient modes, and a model for drift resistive inertial ballooning modes. In the derivation of the MMM8.1 module, effects of collisions, fast ion and impurity dilution, non-circular flux surfaces, finite beta, and Shafranov shift are included. The MMM8.1 is used to compute thermal, particle, toroidal, and poloidal angular momentum transports. The fluid approach which underlies the derivation of MMM8.1 is expected to reliably predict, on an energy transport time scale, the evolution of temperature, density, and momentum profiles in plasma discharges for a wide range of plasma conditions.

Interference of Multi-Mode Gaussian States and "non Appearance" of Quantum Correlations

Science.gov (United States)

Olivares, Stefano

2012-01-01

We theoretically investigate bilinear, mode-mixing interactions involving two modes of uncorrelated multi-mode Gaussian states. In particular, we introduce the notion of "locally the same states" (LSS) and prove that two uncorrelated LSS modes are invariant under the mode mixing, i.e. the interaction does not lead to the birth of correlations between the outgoing modes. We also study the interference of orthogonally polarized Gaussian states by means of an interferometric scheme based on a beam splitter, rotators of polarization and polarization filters.

Cryogenic readout for multiple VUV4 Multi-Pixel Photon Counters in liquid xenon

Science.gov (United States)

Arneodo, F.; Benabderrahmane, M. L.; Bruno, G.; Conicella, V.; Di Giovanni, A.; Fawwaz, O.; Messina, M.; Candela, A.; Franchi, G.

2018-06-01

We present the performances and characterization of an array made of S13370-3050CN (VUV4 generation) Multi-Pixel Photon Counters manufactured by Hamamatsu and equipped with a low power consumption preamplifier operating at liquid xenon temperature (∼ 175 K). The electronics is designed for the readout of a matrix of maximum dimension of 8 × 8 individual photosensors and it is based on a single operational amplifier. The detector prototype presented in this paper utilizes the Analog Devices AD8011 current feedback operational amplifier, but other models can be used depending on the application. A biasing correction circuit has been implemented for the gain equalization of photosensors operating at different voltages. The results show single photon detection capability making this device a promising choice for future generation of large scale dark matter detectors based on liquid xenon, such as DARWIN.

Improving the theoretical foundations of the multi-mode transport model

International Nuclear Information System (INIS)

Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

1999-01-01

A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

Improving the theoretical foundations of the multi-mode transport model

International Nuclear Information System (INIS)

Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

2001-01-01

A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

Vertically integrated pixel readout chip for high energy physics

International Nuclear Information System (INIS)

Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Khalid, Farah; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom

2011-01-01

We report on the development of the vertex detector pixel readout chips based on multi-tier vertically integrated electronics for the International Linear Collider. Some testing results of the VIP2a prototype are presented. The chip is the second iteration of the silicon implementation of the prototype, data-pushed concept of the readout developed at Fermilab. The device was fabricated in the 3D MIT-LL 0.15 (micro)m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 (micro)m 2 pixels, laid out in an array of 48 x 48 pixels.

Charge sharing and charge loss in a cadmium-zinc-telluride fine-pixel detector array

International Nuclear Information System (INIS)

Gaskin, J.A.; Sharma, D.P.; Ramsey, B.D.

2003-01-01

Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium-zinc-telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750 μm pitch), 1 mm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300 μm pitch). Future work will enable us to compare the simulated results for the finer array to measured values

Online probabilistic operational safety assessment of multi-mode engineering systems using Bayesian methods

International Nuclear Information System (INIS)

Lin, Yufei; Chen, Maoyin; Zhou, Donghua

2013-01-01

In the past decades, engineering systems become more and more complex, and generally work at different operational modes. Since incipient fault can lead to dangerous accidents, it is crucial to develop strategies for online operational safety assessment. However, the existing online assessment methods for multi-mode engineering systems commonly assume that samples are independent, which do not hold for practical cases. This paper proposes a probabilistic framework of online operational safety assessment of multi-mode engineering systems with sample dependency. To begin with, a Gaussian mixture model (GMM) is used to characterize multiple operating modes. Then, based on the definition of safety index (SI), the SI for one single mode is calculated. At last, the Bayesian method is presented to calculate the posterior probabilities belonging to each operating mode with sample dependency. The proposed assessment strategy is applied in two examples: one is the aircraft gas turbine, another is an industrial dryer. Both examples illustrate the efficiency of the proposed method

Dynamic configuration management of a multi-standard and multi-mode reconfigurable multi-ASIP architecture for turbo decoding

Science.gov (United States)

Lapotre, Vianney; Gogniat, Guy; Baghdadi, Amer; Diguet, Jean-Philippe

2017-12-01

The multiplication of connected devices goes along with a large variety of applications and traffic types needing diverse requirements. Accompanying this connectivity evolution, the last years have seen considerable evolutions of wireless communication standards in the domain of mobile telephone networks, local/wide wireless area networks, and Digital Video Broadcasting (DVB). In this context, intensive research has been conducted to provide flexible turbo decoder targeting high throughput, multi-mode, multi-standard, and power consumption efficiency. However, flexible turbo decoder implementations have not often considered dynamic reconfiguration issues in this context that requires high speed configuration switching. Starting from this assessment, this paper proposes the first solution that allows frame-by-frame run-time configuration management of a multi-processor turbo decoder without compromising the decoding performances.

Upper Mantle Shear Wave Structure Beneath North America From Multi-mode Surface Wave Tomography

Science.gov (United States)

Yoshizawa, K.; Ekström, G.

2008-12-01

The upper mantle structure beneath the North American continent has been investigated from measurements of multi-mode phase speeds of Love and Rayleigh waves. To estimate fundamental-mode and higher-mode phase speeds of surface waves from a single seismogram at regional distances, we have employed a method of nonlinear waveform fitting based on a direct model-parameter search using the neighbourhood algorithm (Yoshizawa & Kennett, 2002). The method of the waveform analysis has been fully automated by employing empirical quantitative measures for evaluating the accuracy/reliability of estimated multi-mode phase dispersion curves, and thus it is helpful in processing the dramatically increasing numbers of seismic data from the latest regional networks such as USArray. As a first step toward modeling the regional anisotropic shear-wave velocity structure of the North American upper mantle with extended vertical resolution, we have applied the method to long-period three-component records of seismic stations in North America, which mostly comprise the GSN and US regional networks as well as the permanent and transportable USArray stations distributed by the IRIS DMC. Preliminary multi-mode phase-speed models show large-scale patterns of isotropic heterogeneity, such as a strong velocity contrast between the western and central/eastern United States, which are consistent with the recent global and regional models (e.g., Marone, et al. 2007; Nettles & Dziewonski, 2008). We will also discuss radial anisotropy of shear wave speed beneath North America from multi-mode dispersion measurements of Love and Rayleigh waves.

Recent developments with CMOS SSPM photodetectors

Energy Technology Data Exchange (ETDEWEB)

Stapels, Christopher J. [Radiation Monitoring Devices, Inc., Watertown, MA (United States)], E-mail: CStapels@RMDInc.com; Barton, Paul [University of Michigan, Ann Arbor, MI (United States); Johnson, Erik B. [Radiation Monitoring Devices, Inc., Watertown, MA (United States); Wehe, David K. [University of Michigan, Ann Arbor, MI (United States); Dokhale, Purushottam; Shah, Kanai [Radiation Monitoring Devices, Inc., Watertown, MA (United States); Augustine, Frank L. [Augustine Engineering, Encinitas, CA (United States); Christian, James F. [Radiation Monitoring Devices, Inc., Watertown, MA (United States)

2009-10-21

Experiments and simulations using various solid-state photomultiplier (SSPM) designs have been performed to evaluate pixel layouts and explore design choices. SPICE simulations of a design for position-sensing SSPMs showed charge division in the resistor network, and anticipated timing performance of the device. The simulation results predict good position information for resistances in the range of 1-5 k{omega} and 150-{omega} preamplifier input impedance. Back-thinning of CMOS devices can possibly increase the fill factor to 100%, improve spectral sensitivity, and allow for the deposition of anti-reflective coatings after fabrication. We report initial results from back illuminating a CMOS SSPM, and single Geiger-mode avalanche photodiode (GPD) pixels, thinned to 50 {mu}m.

Performance Studies of Pixel Hybrid Photon Detectors for the LHCb RICH Counters

CERN Document Server

Aglieri Rinella, G; Piedigrossi, D; Van Lysebetten, A

2004-01-01

The Pixel Hybrid Photon Detector is a vacuum tube with a multi-alkali photo cathode, high voltage cross-focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a readout CMOS electronic chip fully encapsulated in the device. The Pixel HPD fulfils the requirements of the Ring Imaging Cherenkov counters of the LHCb experiment at LHC. The performances of the Pixel HPD will be discussed with reference to laboratory measurements, Cherenkov light imaging in recent beam tests, image distortions due to a magnetic field.

Integration of geospatial multi-mode transportation Systems in Kuala Lumpur

Science.gov (United States)

Ismail, M. A.; Said, M. N.

2014-06-01

Public transportation serves people with mobility and accessibility to workplaces, health facilities, community resources, and recreational areas across the country. Development in the application of Geographical Information Systems (GIS) to transportation problems represents one of the most important areas of GIS-technology today. To show the importance of GIS network analysis, this paper highlights the determination of the optimal path between two or more destinations based on multi-mode concepts. The abstract connector is introduced in this research as an approach to integrate urban public transportation in Kuala Lumpur, Malaysia including facilities such as Light Rapid Transit (LRT), Keretapi Tanah Melayu (KTM) Komuter, Express Rail Link (ERL), KL Monorail, road driving as well as pedestrian modes into a single intelligent data model. To assist such analysis, ArcGIS's Network Analyst functions are used whereby the final output includes the total distance, total travelled time, directional maps produced to find the quickest, shortest paths, and closest facilities based on either time or distance impedance for multi-mode route analysis.

Integration of geospatial multi-mode transportation Systems in Kuala Lumpur

International Nuclear Information System (INIS)

Ismail, M A; Said, M N

2014-01-01

Public transportation serves people with mobility and accessibility to workplaces, health facilities, community resources, and recreational areas across the country. Development in the application of Geographical Information Systems (GIS) to transportation problems represents one of the most important areas of GIS-technology today. To show the importance of GIS network analysis, this paper highlights the determination of the optimal path between two or more destinations based on multi-mode concepts. The abstract connector is introduced in this research as an approach to integrate urban public transportation in Kuala Lumpur, Malaysia including facilities such as Light Rapid Transit (LRT), Keretapi Tanah Melayu (KTM) Komuter, Express Rail Link (ERL), KL Monorail, road driving as well as pedestrian modes into a single intelligent data model. To assist such analysis, ArcGIS's Network Analyst functions are used whereby the final output includes the total distance, total travelled time, directional maps produced to find the quickest, shortest paths, and closest facilities based on either time or distance impedance for multi-mode route analysis

Bio-Inspired Asynchronous Pixel Event Tricolor Vision Sensor.

Science.gov (United States)

Lenero-Bardallo, Juan Antonio; Bryn, D H; Hafliger, Philipp

2014-06-01

This article investigates the potential of the first ever prototype of a vision sensor that combines tricolor stacked photo diodes with the bio-inspired asynchronous pixel event communication protocol known as Address Event Representation (AER). The stacked photo diodes are implemented in a 22 × 22 pixel array in a standard STM 90 nm CMOS process. Dynamic range is larger than 60 dB and pixels fill factor is 28%. The pixels employ either simple pulse frequency modulation (PFM) or a Time-to-First-Spike (TFS) mode. A heuristic linear combination of the chip's inherent pseudo colors serves to approximate RGB color representation. Furthermore, the sensor outputs can be processed to represent the radiation in the near infrared (NIR) band without employing external filters, and to color-encode direction of motion due to an asymmetry in the update rates of the different diode layers.

Plasmonic nanospherical dimers for color pixels

KAUST Repository

Alrasheed, Salma

2018-04-20

Display technologies are evolving more toward higher resolution and miniaturization. Plasmonic color pixels can offer solutions to realize such technologies due to their sharp resonances and selective scattering and absorption at particular wavelengths. Metal nanosphere dimers are capable of supporting plasmon resonances that can be tuned to span the entire visible spectrum. In this article, we demonstrate numerically bright color pixels that are highly polarized and broadly tuned using periodic arrays of metal nanosphere dimers on a glass substrate. We show that it is possible to obtain RGB pixels in the reflection mode. The longitudinal plasmon resonance of nanosphere dimers along the axis of the dimer is the main contributor to the color of the pixel, while far-field diffractive coupling further enhances and tunes the plasmon resonance. The computational method used is the finite-difference time-domain method. The advantages of this approach include simplicity of the design, bright coloration, and highly polarized function. In addition, we show that it is possible to obtain different colors by varying the angle of incidence, the periodicity, the size of the dimer, the gap, and the substrate thickness.

Hybrid AlGaN-SiC Avalanche Photodiode for Deep-UV Photon Detection

Science.gov (United States)

Aslam, Shahid; Herrero, Federico A.; Sigwarth, John; Goldsman, Neil; Akturk, Akin

2010-01-01

The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep- UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photogenerated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown. The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).

Four-layer DOI PET detectors using a multi-pixel photon counter array and the light sharing method

Energy Technology Data Exchange (ETDEWEB)

Nishikido, Fumihiko, E-mail: funis@nirs.go.jp; Inadama, Naoko; Yoshida, Eiji; Murayama, Hideo; Yamaya, Taiga

2013-11-21

Silicon photomultipliers (SiPMs) provide many advantages for PET detectors, such as their high internal gain, high photon detection efficiency and insensitivity to magnetic fields. The number of detectable scintillation photons of SiPMs, however, is limited by the number of microcells. Therefore, pulse height of PET detectors using SiPMs is saturated when large numbers of scintillation photons enter the SiPM pixels. On the other hand, we previously presented a depth-of-interaction (DOI) encoding method that is based on the light sharing method. Since our encoding method detects scintillation photons with multiple readout pixels, the saturation effect can be suppressed. We constructed two prototype four-layer DOI detectors using a SiPM array and evaluated their performances. The two prototype detectors consisted of four layers of a 6×6 array of Lu{sub 2(1−x)}Y{sub 2x}SiO{sub 5} (LYSO) crystals and a SiPM (multi-pixel photon detector, MPPC, Hamamatsu Photonics K.K.) array of 4×4 pixels. The size of each LYSO crystal element was 1.46 mm×1.46 mm×4.5 mm and all surfaces of the crystal elements were chemically etched. We used two types of MPPCs. The first one had 3600 microcells and high photon detection efficiency (PDE). The other one had 14,400 microcells and lower PDE. In the evaluation experiment, all the crystals of the detector using the MPPC which had the high PDE were clearly identified. The respective energy and timing resolutions of lower than 15% and 1.0 ns were achieved for each crystal element. No saturation of output signals was observed in the 511 keV energy region due to suppression of the saturation effect by detecting scintillation photons with several MPPC pixels by the light sharing method. -- Highlights: •We constructed and evaluated four-layer DOI detectors by the light sharing method using a MPPC array. •The detectors using two types of the MPPC array were compared. •The energy and timing resolutions of lower than 15% and 1.0 ns were

Four-layer DOI PET detectors using a multi-pixel photon counter array and the light sharing method

International Nuclear Information System (INIS)

Nishikido, Fumihiko; Inadama, Naoko; Yoshida, Eiji; Murayama, Hideo; Yamaya, Taiga

2013-01-01

Silicon photomultipliers (SiPMs) provide many advantages for PET detectors, such as their high internal gain, high photon detection efficiency and insensitivity to magnetic fields. The number of detectable scintillation photons of SiPMs, however, is limited by the number of microcells. Therefore, pulse height of PET detectors using SiPMs is saturated when large numbers of scintillation photons enter the SiPM pixels. On the other hand, we previously presented a depth-of-interaction (DOI) encoding method that is based on the light sharing method. Since our encoding method detects scintillation photons with multiple readout pixels, the saturation effect can be suppressed. We constructed two prototype four-layer DOI detectors using a SiPM array and evaluated their performances. The two prototype detectors consisted of four layers of a 6×6 array of Lu 2(1−x) Y 2x SiO 5 (LYSO) crystals and a SiPM (multi-pixel photon detector, MPPC, Hamamatsu Photonics K.K.) array of 4×4 pixels. The size of each LYSO crystal element was 1.46 mm×1.46 mm×4.5 mm and all surfaces of the crystal elements were chemically etched. We used two types of MPPCs. The first one had 3600 microcells and high photon detection efficiency (PDE). The other one had 14,400 microcells and lower PDE. In the evaluation experiment, all the crystals of the detector using the MPPC which had the high PDE were clearly identified. The respective energy and timing resolutions of lower than 15% and 1.0 ns were achieved for each crystal element. No saturation of output signals was observed in the 511 keV energy region due to suppression of the saturation effect by detecting scintillation photons with several MPPC pixels by the light sharing method. -- Highlights: •We constructed and evaluated four-layer DOI detectors by the light sharing method using a MPPC array. •The detectors using two types of the MPPC array were compared. •The energy and timing resolutions of lower than 15% and 1.0 ns were achieved for

Orbital angular momentum mode groups multiplexing transmission over 2.6-km conventional multi-mode fiber.

Science.gov (United States)

Zhu, Long; Wang, Andong; Chen, Shi; Liu, Jun; Mo, Qi; Du, Cheng; Wang, Jian

2017-10-16

Twisted light carrying orbital angular momentum (OAM) is a special kind of structured light that has a helical phase front, a phase singularity, and a doughnut intensity profile. Beyond widespread developments in manipulation, microscopy, metrology, astronomy, nonlinear and quantum optics, OAM-carrying twisted light has seen emerging application of optical communications in free space and specially designed fibers. Instead of specialty fibers, here we show the direct use of a conventional graded-index multi-mode fiber (MMF) for OAM communications. By exploiting fiber-compatible mode exciting and filtering elements, we excite the first four OAM mode groups in an MMF. We demonstrate 2.6-km MMF transmission using four data-carrying OAM mode groups (OAM 0,1 , OAM +1,1 /OAM -1,1 , OAM +2,1 , OAM +3,1 ). Moreover, we demonstrate two data-carrying OAM mode groups multiplexing transmission over the 2.6-km MMF with low-level crosstalk free of multiple-input multiple-output digital signal processing (MIMO-DSP). The demonstrations may open up new perspectives to fiber-based OAM communication/non-communication applications using already existing conventional fibers.

Scalable multi-segment phase mask for spatial power splitting and mode division demultiplexing

NARCIS (Netherlands)

Chen, H.; Koonen, A.M.J.

2013-01-01

Multi-segment Phase Mask (MSPM) designs for spatial power splitting and mode division demultiplexing are verified through simulation and experiments. Coupler insertion loss and mode dependent loss are calculated. A spatial light modulator is used to emulate the proposed MSPMs.

Semi-quartic force fields retrieved from multi-mode expansions: Accuracy, scaling behavior, and approximations

Energy Technology Data Exchange (ETDEWEB)

Ramakrishnan, Raghunathan [Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Rauhut, Guntram, E-mail: rauhut@theochem.uni-stuttgart.de [Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

2015-04-21

Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-Oppenheimer potential energy surface (PES) and are frequently used within the calculation of anharmonic vibrational frequencies based on 2nd order vibrational perturbation theory (VPT2). As such they are usually determined by differentiation of the electronic energy with respect to the nuclear coordinates. Alternatively, potential energy surfaces can be expanded in terms of multi-mode expansions, which typically do not require any derivative techniques. The computational effort to retrieve QFF from size-reduced multi-mode expansions has been studied and has been compared with standard Taylor-expansions. As multi-mode expansions allow for the convenient introduction of subtle approximations, these will be discussed in some detail. In addition, a preliminary study about the applicability of a generalized Duschinsky transformation to QFFs is provided. This transformation allows for the efficient evaluation of VPT2 frequencies of isotopologues from the PES of the parent compound and thus avoids the recalculation of PESs in different axes systems.

A Novel Atomic Force Microscope with Multi-Mode Scanner

International Nuclear Information System (INIS)

Qin, Chun; Zhang, Haijun; Xu, Rui; Han, Xu; Wang, Shuying

2016-01-01

A new type of atomic force microscope (AFM) with multi-mode scanner is proposed. The AFM system provides more than four scanning modes using a specially designed scanner with three tube piezoelectric ceramics and three stack piezoelectric ceramics. Sample scanning of small range with high resolution can be realized by using tube piezos, meanwhile, large range scanning can be achieved by stack piezos. Furthermore, the combination with tube piezos and stack piezos not only realizes high-resolution scanning of small samples with large- scale fluctuation structure, but also achieves small range area-selecting scanning. Corresponding experiments are carried out in terms of four different scanning modes showing that the AFM is of reliable stability, high resolution and can be widely applied in the fields of micro/nano-technology. (paper)

Development of the MCM-D technique for pixel detector modules

International Nuclear Information System (INIS)

Grah, C.

2005-03-01

This thesis treats a copper--polymer based thin film technology, the MCM-D technique and its application when building hybrid pixel detector modules. The ATLAS experiment at the LHC will be equipped with a pixel detector system. The basic mechanical units of the pixel detector are multi chip modules. The main components of these modules are: 16 electronic chips, a controller chip and a large sensor tile, featuring more than 46000 sensor cells. MCM-D is a superior technique to build the necessary signal bus system and the power distribution system directly on the active sensor tile. In collaboration with the Fraunhofer Institute for Reliability and Microintegration, IZM, the thin film process is reviewed and enhanced. The multi layer system was designed and optimized for the interconnection system as well as for the 46000 pixel contacts. Laboratory measurements on prototypes prove that complex routing schemes for geometrically optimized single chips are suitable and have negligible influence on the front--end chips performance. A full scale MCM-D module has been built and it is shown that the technology is suitable to build pixel detector modules. Further tests include the investigation of the impact of hadronic irradiation on the thin film layers. Single chip assemblies have been operated in a test beam environment and the feasibility of the optimization of the sensors could be shown. A review on the potential as well as the perspective for the MCM-D technique in future experiments is given

Multi-Pixel Simultaneous Classification of PolSAR Image Using Convolutional Neural Networks

Science.gov (United States)

Xu, Xin; Gui, Rong; Pu, Fangling

2018-01-01

Convolutional neural networks (CNN) have achieved great success in the optical image processing field. Because of the excellent performance of CNN, more and more methods based on CNN are applied to polarimetric synthetic aperture radar (PolSAR) image classification. Most CNN-based PolSAR image classification methods can only classify one pixel each time. Because all the pixels of a PolSAR image are classified independently, the inherent interrelation of different land covers is ignored. We use a fixed-feature-size CNN (FFS-CNN) to classify all pixels in a patch simultaneously. The proposed method has several advantages. First, FFS-CNN can classify all the pixels in a small patch simultaneously. When classifying a whole PolSAR image, it is faster than common CNNs. Second, FFS-CNN is trained to learn the interrelation of different land covers in a patch, so it can use the interrelation of land covers to improve the classification results. The experiments of FFS-CNN are evaluated on a Chinese Gaofen-3 PolSAR image and other two real PolSAR images. Experiment results show that FFS-CNN is comparable with the state-of-the-art PolSAR image classification methods. PMID:29510499

Four-layer depth-of-interaction PET detector for high resolution PET using a multi-pixel S8550 avalanche photodiode

Energy Technology Data Exchange (ETDEWEB)

Nishikido, Fumihiko, E-mail: funis@nirs.go.j [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Inadama, Naoko [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Oda, Ichiro [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Shibuya, Kengo; Yoshida, Eiji; Yamaya, Taiga [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kitamura, Keishi [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Murayama, Hideo [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2010-09-21

Avalanche photodiodes (APDs) are being used as photodetectors in positron emission tomography (PET) because they have many advantages over photomultipliers (PMTs) typically used in PET detectors. We have developed a PET detector that consists of a multi-pixel APD and a 6x6x4 array of 1.46x1.46 mm{sup 2}x4.5 m LYSO crystals for a small animal PET scanner. The detector can identify four-layer depth of interaction (DOI) with a position-sensitive APD coupled to the backside of a crystal array by just an optimized reflector arrangement. Since scintillation lights are shared among many pixels by the method, weaker signals in APD pixels far from the interacting crystals are affected by noise. To evaluate the performance of the four-layer DOI detector with the APD and the influence of electrical noise on our method, we constructed a prototype DOI detector and tested its performance. We found, except for crystal elements on the edge of the crystal array, all crystal elements could be identified from the 2D position histogram. An energy resolution of 16.9% was obtained for the whole crystal array of the APD detector. The results of noise dependence of detector performances indicated that the DOI detector using the APD could achieve sufficient performance even when using application-specific integrated circuits.

Four-layer depth-of-interaction PET detector for high resolution PET using a multi-pixel S8550 avalanche photodiode

International Nuclear Information System (INIS)

Nishikido, Fumihiko; Inadama, Naoko; Oda, Ichiro; Shibuya, Kengo; Yoshida, Eiji; Yamaya, Taiga; Kitamura, Keishi; Murayama, Hideo

2010-01-01

Avalanche photodiodes (APDs) are being used as photodetectors in positron emission tomography (PET) because they have many advantages over photomultipliers (PMTs) typically used in PET detectors. We have developed a PET detector that consists of a multi-pixel APD and a 6x6x4 array of 1.46x1.46 mm 2 x4.5 m LYSO crystals for a small animal PET scanner. The detector can identify four-layer depth of interaction (DOI) with a position-sensitive APD coupled to the backside of a crystal array by just an optimized reflector arrangement. Since scintillation lights are shared among many pixels by the method, weaker signals in APD pixels far from the interacting crystals are affected by noise. To evaluate the performance of the four-layer DOI detector with the APD and the influence of electrical noise on our method, we constructed a prototype DOI detector and tested its performance. We found, except for crystal elements on the edge of the crystal array, all crystal elements could be identified from the 2D position histogram. An energy resolution of 16.9% was obtained for the whole crystal array of the APD detector. The results of noise dependence of detector performances indicated that the DOI detector using the APD could achieve sufficient performance even when using application-specific integrated circuits.

Brightness enhancement of a multi-mode ribbon fiber using transmitting Bragg gratings

Science.gov (United States)

Anderson, B. M.; Venus, G.; Ott, D.; Divliansky, I.; Dawson, J. W.; Drachenberg, D. R.; Messerly, M. J.; Pax, P. H.; Tassano, J. B.; Glebov, L. B.

2015-03-01

Increasing the dimensions of a waveguide provides the simplest means of reducing detrimental nonlinear effects, but such systems are inherently multi-mode, reducing the brightness of the system. Furthermore, using rectangular dimensions allows for improved heat extraction, as well as uniform temperature profile within the core. We propose a method of using the angular acceptance of a transmitting Bragg grating (TBG) to filter the fundamental mode of a fiber laser resonator, and as a means to increase the brightness of multi-mode fiber laser. Numerical modeling is used to calculate the diffraction losses needed to suppress the higher order modes in a laser system with saturable gain. The model is tested by constructing an external cavity resonator using an ytterbium doped ribbon fiber with core dimensions of 107.8μm by 8.3μm as the active medium. We show that the TBG increases the beam quality of the system from M2 = 11.3 to M2 = 1.45, while reducing the slope efficiency from 76% to 53%, overall increasing the brightness by 5.1 times.

Construction techniques and working principles of external cathode Geiger-Mueller counters

International Nuclear Information System (INIS)

Sevegnani, Francisco Xavier

1996-01-01

In this paper, the construction technique and working principles of the external cathode Geiger-Mueller counter are described in detail. During the analysis of the behavior of these counters a new phenomena was observed, related to an increase int he background rate with the applied voltage. The experiments have also shown that the pulse amplitude of those counters decreases exponentially with the counting rate. The counters built with the techniques described in this paper has shown plateaus of about 1400 V with slope of 0,8%/100 V. (author)

A multi-mode operation control strategy for flexible microgrid based on sliding-mode direct voltage and hierarchical controls.

Science.gov (United States)

Zhang, Qinjin; Liu, Yancheng; Zhao, Youtao; Wang, Ning

2016-03-01

Multi-mode operation and transient stability are two problems that significantly affect flexible microgrid (MG). This paper proposes a multi-mode operation control strategy for flexible MG based on a three-layer hierarchical structure. The proposed structure is composed of autonomous, cooperative, and scheduling controllers. Autonomous controller is utilized to control the performance of the single micro-source inverter. An adaptive sliding-mode direct voltage loop and an improved droop power loop based on virtual negative impedance are presented respectively to enhance the system disturbance-rejection performance and the power sharing accuracy. Cooperative controller, which is composed of secondary voltage/frequency control and phase synchronization control, is designed to eliminate the voltage/frequency deviations produced by the autonomous controller and prepare for grid connection. Scheduling controller manages the power flow between the MG and the grid. The MG with the improved hierarchical control scheme can achieve seamless transitions from islanded to grid-connected mode and have a good transient performance. In addition the presented work can also optimize the power quality issues and improve the load power sharing accuracy between parallel VSIs. Finally, the transient performance and effectiveness of the proposed control scheme are evaluated by theoretical analysis and simulation results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Optimal sensor configuration for flexible structures with multi-dimensional mode shapes

International Nuclear Information System (INIS)

Chang, Minwoo; Pakzad, Shamim N

2015-01-01

A framework for deciding the optimal sensor configuration is implemented for civil structures with multi-dimensional mode shapes, which enhances the applicability of structural health monitoring for existing structures. Optimal sensor placement (OSP) algorithms are used to determine the best sensor configuration for structures with a priori knowledge of modal information. The signal strength at each node is evaluated by effective independence and modified variance methods. Euclidean norm of signal strength indices associated with each node is used to expand OSP applicability into flexible structures. The number of sensors for each method is determined using the threshold for modal assurance criterion (MAC) between estimated (from a set of observations) and target mode shapes. Kriging is utilized to infer the modal estimates for unobserved locations with a weighted sum of known neighbors. A Kriging model can be expressed as a sum of linear regression and random error which is assumed as the realization of a stochastic process. This study presents the effects of Kriging parameters for the accurate estimation of mode shapes and the minimum number of sensors. The feasible ranges to satisfy MAC criteria are investigated and used to suggest the adequate searching bounds for associated parameters. The finite element model of a tall building is used to demonstrate the application of optimal sensor configuration. The dynamic modes of flexible structure at centroid are appropriately interpreted into the outermost sensor locations when OSP methods are implemented. Kriging is successfully used to interpolate the mode shapes from a set of sensors and to monitor structures associated with multi-dimensional mode shapes. (paper)

Charge Gain, Voltage Gain, and Node Capacitance of the SAPHIRA Detector Pixel by Pixel

Science.gov (United States)

Pastrana, Izabella M.; Hall, Donald N. B.; Baker, Ian M.; Jacobson, Shane M.; Goebel, Sean B.

2018-01-01

The University of Hawai`i Institute for Astronomy has partnered with Leonardo (formerly Selex) in the development of HgCdTe linear mode avalanche photodiode (L-APD) SAPHIRA detectors. The SAPHIRA (Selex Avalanche Photodiode High-speed Infra-Red Array) is ideally suited for photon-starved astronomical observations, particularly near infrared (NIR) adaptive optics (AO) wave-front sensing. I have measured the stability, and linearity with current, of a 1.7-um (10% spectral bandpass) infrared light emitting diode (IR LED) used to illuminate the SAPHIRA and have then utilized this source to determine the charge gain (in e-/ADU), voltage gain (in uV/ADU), and node capacitance (in fF) for each pixel of the 320x256@24um SAPHIRA. These have previously only been averages over some sub-array. Determined from the ratio of the temporal averaged signal level to variance under constant 1.7-um LED illumination, I present the charge gain pixel-by-pixel in a 64x64 sub-array at the center of the active area of the SAPHIRA (analyzed separately as four 32x32 sub-arrays) to be about 1.6 e-/ADU (σ=0.5 e-/ADU). Additionally, the standard technique of varying the pixel reset voltage (PRV) in 10 mV increments and recording output frames for the same 64x64 subarray found the voltage gain per pixel to be about 11.7 uV/ADU (σ=0.2 uV/ADU). Finally, node capacitance was found to be approximately 23 fF (σ=6 fF) utilizing the aforementioned charge and voltage gain measurements. I further discuss the linearity measurements of the 1.7-um LED used in the charge gain characterization procedure.

Layered Multi-mode Optimal Control Strategy for Multi-MW Wind Turbine

Institute of Scientific and Technical Information of China (English)

KONG Yi-gang; WANG Zhi-xin

2008-01-01

The control strategy is one of the most important renewable technology, and an increasing number of multi-MW wind turbines are being developed with a variable speed-variable pitch (VS-VP) technology. The main objective of adopting a VS-VP technology is to improve the fast response speed and capture maximum energy. But the power generated by wind turbine changes rapidly because of the centinuous fluctuation of wind speed and direction. At the same time, wind energy conversion systems are of high order, time delays and strong nonlinear characteristics because of many uncertain factors. Based on analyzing the all dynamic processes of wind turbine, a kind of layered multi-mode optimal control strategy is presented which is that three control strategies: bang-bang, fuzzy and adaptive proportienai integral derivative (PID) are adopted according to different stages and expected performance of wind turbine to capture optimum wind power, compensate the nonlinearity and improve the wind turbine performance at low, rated and high wind speed.

Multi-Pixel Photon Counters for Optofluidic Characterization of Particles and Microalgae

Directory of Open Access Journals (Sweden)

Pouya Asrar

2015-06-01

Full Text Available We have developed an optofluidic biosensor to study microscale particles and different species of microalgae. The system is comprised of a microchannel with a set of chevron-shaped grooves. The chevrons allows for hydrodynamic focusing of the core stream in the center using a sheath fluid. The device is equipped with a new generation of highly sensitive photodetectors, multi-pixel photon counter (MPPC, with high gain values and an extremely small footprint. Two different sizes of high intensity fluorescent microspheres and three different species of algae (Chlamydomonas reinhardtii strain 21 gr, Chlamydomonas suppressor, and Chlorella sorokiniana were studied. The forward scattering emissions generated by samples passing through the interrogation region were carried through a multimode fiber, located in 135 degree with respect to the excitation fiber, and detected by a MPPC. The signal outputs obtained from each sample were collected using a data acquisition system and utilized for further statistical analysis. Larger particles or cells demonstrated larger peak height and width, and consequently larger peak area. The average signal output (integral of the peak for Chlamydomonas reinhardtii strain 21 gr, Chlamydomonas suppressor, and Chlorella sorokiniana falls between the values found for the 3.2 and 10.2 μm beads. Different types of algae were also successfully characterized.

A liquid-crystal-on-silicon color sequential display using frame buffer pixel circuits

Science.gov (United States)

Lee, Sangrok

Next generation liquid-crystal-on-silicon (LCOS) high definition (HD) televisions and image projection displays will need to be low-cost and high quality to compete with existing systems based on digital micromirror devices (DMDs), plasma displays, and direct view liquid crystal displays. In this thesis, a novel frame buffer pixel architecture that buffers data for the next image frame while displaying the current frame, offers such a competitive solution is presented. The primary goal of the thesis is to demonstrate the LCOS microdisplay architecture for high quality image projection displays and at potentially low cost. The thesis covers four main research areas: new frame buffer pixel circuits to improve the LCOS performance, backplane architecture design and testing, liquid crystal modes for the LCOS microdisplay, and system integration and demonstration. The design requirements for the LCOS backplane with a 64 x 32 pixel array are addressed and measured electrical characteristics matches to computer simulation results. Various liquid crystal (LC) modes applicable for LCOS microdisplays and their physical properties are discussed. One- and two-dimensional director simulations are performed for the selected LC modes. Test liquid crystal cells with the selected LC modes are made and their electro-optic effects are characterized. The 64 x 32 LCOS microdisplays fabricated with the best LC mode are optically tested with interface circuitry. The characteristics of the LCOS microdisplays are summarized with the successful demonstration.

Response of a hybrid pixel detector (MEDIPIX3) to different radiation sources for medical applications

Energy Technology Data Exchange (ETDEWEB)

Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, E., E-mail: emoreno.emb@gmail.com [Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Rio Verde, Puebla (Mexico); Moreno Barbosa, F. [Hospital General del Sur Hospital de la Mujer, Puebla (Mexico)

2014-11-07

The development in semiconductor CMOS technology has enabled the creation of sensitive detectors for a wide range of ionizing radiation. These devices are suitable for photon counting and can be used in imaging and tomography X-ray diagnostics. The Medipix[1] radiation detection system is a hybrid silicon pixel chip developed for particle tracking applications in High Energy Physics. Its exceptional features (high spatial and energy resolution, embedded ultra fast readout, different operation modes, etc.) make the Medipix an attractive device for applications in medical imaging. In this work the energy characterization of a third-generation Medipix chip (Medipix3) coupled to a silicon sensor is presented. We used different radiation sources (strontium 90, iron 55 and americium 241) to obtain the response curve of the hybrid detector as a function of energy. We also studied the contrast of the Medipix as a measure of pixel noise. Finally we studied the response to fluorescence X rays from different target materials (In, Pd and Cd) for the two data acquisition modes of the chip; single pixel mode and charge summing mode.

Heralded source of bright multi-mode mesoscopic sub-Poissonian light

DEFF Research Database (Denmark)

Iskhakov, Timur; Usenko, V. C.; Andersen, Ulrik Lund

2016-01-01

In a direct detection scheme, we observed 7.8 dB of twin-beam squeezing for multi-mode two-color squeezed vacuum generated via parametric downconversion. Applying postselection, we conditionally prepared a sub-Poissonian state of light containing 6.3 . 105 photons per pulse on the average...

Multi-Mode Operation for On-line Uninterruptible Power Supply System

DEFF Research Database (Denmark)

Lu, Jinghang; Savaghebi, Mehdi; Golestan, Saeed

2018-01-01

To enhance the robustness and disturbance rejection ability of an on-line uninterruptible power supply (UPS) system, an Internal Model Control (IMC)-based DC-link voltage regulation method is proposed in this paper. Furthermore, the multi-mode operations of the on-line UPS system are investigated...

A multi-channel coronal spectrophotometer.

Science.gov (United States)

Landman, D. A.; Orrall, F. Q.; Zane, R.

1973-01-01

We describe a new multi-channel coronal spectrophotometer system, presently being installed at Mees Solar Observatory, Mount Haleakala, Maui. The apparatus is designed to record and interpret intensities from many sections of the visible and near-visible spectral regions simultaneously, with relatively high spatial and temporal resolution. The detector, a thermoelectrically cooled silicon vidicon camera tube, has its central target area divided into a rectangular array of about 100,000 pixels and is read out in a slow-scan (about 2 sec/frame) mode. Instrument functioning is entirely under PDP 11/45 computer control, and interfacing is via the CAMAC system.

Tuning the dispersion and single/multi-modeness of a hole-assisted fiber by the hole's geometrical parameters

NARCIS (Netherlands)

Uranus, H.P.; Hoekstra, Hugo; van Groesen, Embrecht W.C.

2008-01-01

Using a vectorial finite element mode solver developed earlier, we studied a hole-assisted multi-ring fiber. We report the role of the hole’s geometrical parameters in tuning the waveguide dispersion and the single/multi-modeness of the particular fiber. By correctly selecting the hole’s size and

Test Beam Results of Geometry Optimized Hybrid Pixel Detectors

CERN Document Server

Becks, K H; Grah, C; Mättig, P; Rohe, T

2006-01-01

The Multi-Chip-Module-Deposited (MCM-D) technique has been used to build hybrid pixel detector assemblies. This paper summarises the results of an analysis of data obtained in a test beam campaign at CERN. Here, single chip hybrids made of ATLAS pixel prototype read-out electronics and special sensor tiles were used. They were prepared by the Fraunhofer Institut fuer Zuverlaessigkeit und Mikrointegration, IZM, Berlin, Germany. The sensors feature an optimized sensor geometry called equal sized bricked. This design enhances the spatial resolution for double hits in the long direction of the sensor cells.

Reconfigurable Bandpass Sigma-Delta Modulator With Programmable NTF for Low-IF Multi-Mode Receivers

DEFF Research Database (Denmark)

Zhang, Ke; Mikkelsen, Jan H.; Shen, Ming

2012-01-01

transfer function of the loop while still maintaining stability. Compared with conventional multi-mode BPSDM, employing cascade structures and multi-bit sub-ADCs, the proposed modulator features many attractive advantages, such as (1) avoiding coefficient mismatch between analog and digital components...

Pixel readout chips in deep submicron CMOS for ALICE and LHCb tolerant to 10 Mrad and beyond

International Nuclear Information System (INIS)

Snoeys, W.; Burns, M.; Campbell, M.; Cantatore, E.; Cencelli, V.; Dinapoli, R.; Heijne, E.; Jarron, P.; Lamanna, P.; Minervini, D.; Morel, M.; O'Shea, V.; Quiquempoix, V.; Bello, D.S.S.D.San Segundo; Van Koningsveld, B.; Wyllie, K.

2001-01-01

The ALICE1LHCB chip is a mixed-mode integrated circuit designed to read out silicon pixel detectors for two different applications: particle tracking in the ALICE Silicon Pixel Detector and particle identification in the LHCb Ring Imaging Cherenkov detector. To satisfy the different needs for these two experiments, the chip can be operated in two different modes. In tracking mode all the 50 μmx425 μm pixel cells in the 256x32 array are read out individually, whilst in particle identification mode they are combined in groups of 8 to form a 32x32 array of 400 μmx425 μm cells. Radiation tolerance was enhanced through special circuit layout. Sensitivity to coupling of digital signals into the analog front end was minimized. System issues such as testability and uniformity further constrained the design. The circuit is currently being manufactured in a commercial 0.25 μm CMOS technology

FE-I4 pixel chip characterization with USBpix3 test system

Energy Technology Data Exchange (ETDEWEB)

Filimonov, Viacheslav; Gonella, Laura; Hemperek, Tomasz; Huegging, Fabian; Janssen, Jens; Krueger, Hans; Pohl, David-Leon; Wermes, Norbert [University of Bonn, Bonn (Germany)

2015-07-01

The USBpix readout system is a small and light weighting test system for the ATLAS pixel readout chips. It is widely used to operate and characterize FE-I4 pixel modules in lab and test beam environments. For multi-chip modules the resources on the Multi-IO board, that is the central control unit of the readout system, are coming to their limits, which makes the simultaneous readout of more than one chip at a time challenging. Therefore an upgrade of the current USBpix system has been developed. The upgraded system is called USBpix3 - the main focus of the talk. Characterization of single chip FE-I4 modules was performed with USBpix3 prototype (digital, analog, threshold and source scans; tuning). PyBAR (Bonn ATLAS Readout in Python scripting language) was used as readout software. PyBAR consists of FEI4 DAQ and Data Analysis Libraries in Python. The presentation describes the USBpix3 system, results of FE-I4 modules characterization and preparation for the multi-chip module and multi-module readout with USBpix3.

Cosmic rays with portable Geiger counters: from sea level to airplane cruise altitudes

Energy Technology Data Exchange (ETDEWEB)

Blanco, Francesco; La Rocca, Paola; Riggi, Francesco [Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, I-95123 Catania (Italy)], E-mail: Francesco.Riggi@ct.infn.it

2009-07-15

Cosmic ray count rates with a set of portable Geiger counters were measured at different altitudes on the way to a mountain top and aboard an aircraft, between sea level and cruise altitude. Basic measurements may constitute an educational activity even with high school teams. For the understanding of the results obtained, simulations of extensive air showers induced by high-energy primary protons in the atmosphere were also carried out, involving undergraduate and graduate teaching levels.

Radiation level measured by a portable Geiger-Mueller counter at the altitude of commercial air routes

International Nuclear Information System (INIS)

Araki, Takashi

1995-01-01

The background intensities of naturally occurring radiation were measured aboard scheduled commercial airplanes using a newly developed Geiger-Mueller counter with a pocket computer. The preliminary results show that the radiation at the cruising altitude of a commercial airplane on a transcontinental flight is 40 times higher than the ground-level. (author)

Geiger-Mueller haloid counter dead time dependence on counting rate

International Nuclear Information System (INIS)

Onishchenko, A.M.; Tsvetkov, A.A.

1980-01-01

The experimental dependences of the dead time of Geiger counters (SBM-19, SBM-20, SBM-21 and SGM-19) on the loading, are presented. The method of two sources has been used to determine the dead time counters of increased stability. The counters are switched on according to the usually used circuit of discrete counting with loading resistance of 50 MOhm and the separating capacity of 10 pF. Voltage pulses are given to the counting device with the time of resolution of 100 ns, discrimenation threshold 3 V, input resistance 3.6 Ω and the input capacity-15 pF. The time constant of the counter RC-circuit is 50 μs

Optical readout in a multi-module system test for the ATLAS pixel detector

International Nuclear Information System (INIS)

Flick, Tobias; Becks, Karl-Heinz; Gerlach, Peter; Kersten, Susanne; Maettig, Peter; Nderitu Kirichu, Simon; Reeves, Kendall; Richter, Jennifer; Schultes, Joachim

2006-01-01

The innermost part of the ATLAS experiment at the LHC, CERN, will be a pixel detector, which is presently under construction. The command messages and the readout data of the detector are transmitted over an optical data path. The readout chain consists of many components which are produced at several locations around the world, and must work together in the pixel detector. To verify that these parts are working together as expected a system test has been built up. It consists of detector modules, optoboards, optical fibres, Back of Crate cards, Readout Drivers, and control computers. In this paper, the system test setup and the operation of the readout chain are described. Also, some results of tests using the final pixel detector readout chain are given

A current-mode multi-valued adder circuit for multi-operand addition

Science.gov (United States)

Cini, Ugur; Morgül, Avni

2011-06-01

Static CMOS logic circuits have a robust working performance. However, they generate excessive noise when the switching activity is high. Source-coupled logic (SCL) circuits can be an alternative for analogue-friendly design where constant current is driven from the power supply, independent of the switching activity of the circuit. In this work, a compact current-mode multi-operand adder cell, similar to SCL circuits, is designed. The circuit adds up seven input operands using a technique similar to the (7, 3) counter circuit, but with less active elements when compared to a conventional binary (7, 3) counter. The design has comparable power and delay characteristics compared to conventional SCL implementation. The proposed circuit requires only 69 transistors, where 96 transistors are required for the equivalent SCL implementation. Hence the circuit saves on both transistor count and interconnections. The design is optimised for low power operation of high performance arithmetic circuits. The proposed multi-operand adder circuit is designed in UMC 0.18 µm technology. As an example of application, an 8 × 8 bit multiplier circuit is designed and simulated using HSPICE.

Amplitude and timing properties of a Geiger discharge in a SiPM cell

Energy Technology Data Exchange (ETDEWEB)

Popova, E., E-mail: elenap73@mail.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Kashirskoe Shosse 31 (Russian Federation); Buzhan, P.; Pleshko, A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Kashirskoe Shosse 31 (Russian Federation); Vinogradov, S. [University of Liverpool and Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Warrington WA4 4AD, Cheshire (United Kingdom); P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninskiy Prospect 53, Moscow 119991 (Russian Federation); Stifutkin, A.; Ilyin, A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Kashirskoe Shosse 31 (Russian Federation); Besson, D. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Kashirskoe Shosse 31 (Russian Federation); Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045-2151 (United States); Mirzoyan, R. [Max-Planck-Institute for Physics, Föhringer Ring 6, 80805 München (Germany)

2015-07-01

The amplitude and timing properties of a Geiger discharge in a stand-alone SiPM cell have been investigated in detail. Use of a single stand-alone SiPM cell allows us to perform measurements with better accuracy than the multicell structure of conventional SiPMs. We have studied the dependence of the output charge and amplitude from an SiPM cell illuminated by focused light vs the number of primary photoelectrons. We propose a SPICE model which explains the amplitude over saturation (when the SiPM's amplitude is greater than the sum over all cells) characteristics of SiPM signals for more than one initial photoelectrons. The time resolutions of a SiPM cell have been measured for the case of single (SPTR) and multiphoton light pulses. The Full Width Half Max (FWHM) for SPTR has been found to be at the level of 30 ps for focused and 40 ps for unfocused light (100 μm cell size). - Highlights: • A stand-alone SiPM cell has been investigated in detail. • Amplitude and time properties have been measured with femtosecond 660 nm laser. • SPICE model for a Geiger discharge development has been proposed. • SPTR for a stand-alone 100 μm size SiPM cell has been found to be 40 ps FWHM.

Construction and operating characteristics of flexible Geiger counters; Caracteristiques de construction et d'utilisation de compteurs Geiger flexibles; Konstruktsionnaya i operativnaya kharakteristiki gibkikh schetchikov Gejgera; Construccion y caracteristicas de funcionamiento de contadores Geiger flexibles

Energy Technology Data Exchange (ETDEWEB)

Richter, H G; Ballard, L F [Research Triangle Institute, Durham, NC (United States)

1962-04-15

point une methode de construction de compteurs Geiger flexibles ayant des dimensions tres variees. Les compteurs sont tres flexibles : un compteur de 3 cm de diametre peut etre plie avec un rayon de courbure de 5 cm. En utilisant du gaz Q (98,3% d'helium et 1,7% de n-butane) comme milieu de comptage, les paliers ont une longueur de plusieurs centaines de volts avec une pente de 3% et sont independants de la configuration geometrique du compteur. Les compteurs sont construits avec des tubes en chlorure de polyvinyle (PVC-744 - Alpha Wire Corp.). De courts segments du tube (longueur egale a environ 3 fois le diametre) sont glisses sur un mandrin d'aluminium grossierement filete et entoures d'un fil fortement serre. Le tout est place dans un four a 110{sup o}C pendant 20 minutes. Apres refroidissement, le segment de matiere plastique ainsi cannele est degage du mandrin. Ce traitement du tube empeche sa rupture lorsqu'il est enroule. Un disque de polystyrene, perfore de trous relativement grands a la peripherie pour l'ecoulement du gaz et d'un trou central de 0,6 mm pour le passage de l'anode, est attache a une extremite de chaque segment. En enfilant les segments ainsi prepares sur une anode en tungstene de 3 mm, en glissant une extremite de chaque segment sur le segment adjacent et en les fixant solidement avec un adhesif, on peut construire un compteur d'une longueur quelconque. On attache aux extremites des pieces en verre pour la fixation de l'anode et pour l'admission et l'evacuation du gaz. Un fil de cuivre nu, entoure en spirale dans les cannelures du compteur, donne une cathode externe satisfaisante, qui fonctionne suivant le mode observe par Maze. Un compteur de 3 cm de diametre et de 1 metre de longueur, lineaire ou enroule, possede un palier commencant a 1400 volts et allant jusqu'a 1700 volts avec une pente de 2,9%. On a enregistre des taux de comptage de plus de 300000 coups par minute, avec peu de pertes par coincidences. Comme le compteur est en fait une

Hybrid UWB and WiMAX radio-over-multi-mode fibre for in-building optical networks

International Nuclear Information System (INIS)

Perez, J; Llorente, R

2014-01-01

In this paper the use of hybrid WiMedia-defined ultra-wideband (UWB) and IEEE 802.16d WiMAX radio-over-fibre is proposed and experimentally demonstrated for multi-mode based in-building optical networks with the advantage of great immunity to optical transmission impairments. In the proposed approach, spectral coexistence of both signals must be achieved with negligible mutual interference. The experimental study performed addressed an indoor configuration with 50 μm multi-mode fibres (MMF) and 850 nm vertical-cavity surface-emitting laser (VCSEL) transmitters. The results indicate that the impact of the wireless convergence in radio-over-multi-mode fibre (RoMMF) is significant for UWB transmissions, mainly due to MMF dispersion and electrooptical (EO) devices with limited bandwidth. On the other hand, WiMAX transmission is feasible for a 300 m MMF and 30 m wireless link in the presence of UWB, with −31 dBm WiMAX EVM. (paper)

Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

International Nuclear Information System (INIS)

Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

2015-01-01

A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s. (paper)

Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

Science.gov (United States)

Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

2015-03-01

A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s.

Predictive simulations of radio frequency heated plasmas of Tore Supra using the Multi-Mode model

International Nuclear Information System (INIS)

Voitsekhovitch, Irina; Bateman, Glenn; Kritz, Arnold H.; Pankin, Alexei

2002-01-01

Multichannel integrated predictive simulations using the Multi-Mode transport model are carried out for radio frequency heated Tore Supra tokamak discharges in which helium is the primary ion component. Lower hybrid heated discharges in which the total current is driven noninductively [X. Litaudon et al., Plasma Phys. Controlled Fusion 43, 677 (2001)] and a discharge with ion cyclotron radio frequency heating of the hydrogen minority ions [G. T. Hoang et al., Nucl. Fusion 38, 117 (1998)] are simulated. The simulations of these discharges represent the first test of the Multi-Mode model in helium plasmas with dominant electron heating. Also for the first time, the particle transport in Tore Supra discharges is computed and the density profiles are predicted self-consistently with other transport channels. It is found in these simulations that the anomalous transport driven by trapped electron mode turbulence is dominant compared to the transport driven by the ion temperature gradient turbulence. The feature of the Multi-Mode model to calculate the impurity transport self-consistently with other transport channels is used in this study to predict the influence of carbon impurity influx on the discharge evolution

Fano resonances in a high-Q terahertz whispering-gallery mode resonator coupled to a multi-mode waveguide.

Science.gov (United States)

Vogt, Dominik Walter; Leonhardt, Rainer

2017-11-01

We report on Fano resonances in a high-quality (Q) whispering-gallery mode (WGM) spherical resonator coupled to a multi-mode waveguide in the terahertz (THz) frequency range. The asymmetric line shape and phase of the Fano resonances detected with coherent continuous-wave (CW) THz spectroscopy measurements are in excellent agreement with the analytical model. A very high Q factor of 1600, and a finesse of 22 at critical coupling is observed around 0.35 THz. To the best of our knowledge this is the highest Q factor ever reported for a THz WGM resonator.

The Level 0 Pixel Trigger system for the ALICE experiment

International Nuclear Information System (INIS)

Rinella, G Aglieri; Kluge, A; Krivda, M

2007-01-01

The ALICE Silicon Pixel Detector contains 1200 readout chips. Fast-OR signals indicate the presence of at least one hit in the 8192 pixel matrix of each chip. The 1200 bits are transmitted every 100 ns on 120 data readout optical links using the G-Link protocol. The Pixel Trigger System extracts and processes them to deliver an input signal to the Level 0 trigger processor targeting a latency of 800 ns. The system is compact, modular and based on FPGA devices. The architecture allows the user to define and implement various trigger algorithms. The system uses advanced 12-channel parallel optical fiber modules operating at 1310 nm as optical receivers and 12 deserializer chips closely packed in small area receiver boards. Alternative solutions with multi-channel G-Link deserializers implemented directly in programmable hardware devices were investigated. The design of the system and the progress of the ALICE Pixel Trigger project are described in this paper

Body-insensitive Multi-Mode MIMO Terminal Antenna of Double-Ring Structure

DEFF Research Database (Denmark)

Zhao, Kun; Zhang, Shuai; Ishimiya, Katsunori

2015-01-01

of mobile terminals. With the multimode excitation, the MIMO cellular antenna can operate at 830-900 MHz, 1700-2200 MHz, and 2400-2700 MHz, for 2G, 3G, and LTE bands, respectively. The MIMO Wi-Fi antenna can cover two Wi-Fi bands from 2.4 to 2.5 GHz and from 5.2 to 5.8 GHz. The effect of a user's body......In this paper, we propose a novel multimode multi-input multi-output (MIMO) antenna system composed of a dual-element MIMO cellular antenna and dual-element MIMO Wi-Fi antenna for mobile terminal applications. The antenna system has a double-ring structure and can be integrated with the metal frame...... on the MIMO cellular antenna is investigated on CTIA standard phantoms and a real user. Since our antenna mainly operates in the loop mode, it has a much lower efficiency loss than conventional mobile antennas in both talking and data modes. Our theoretical analysis and experiments have shown that our design...

Experimental characterization of the 192 channel Clear-PEM frontend ASIC coupled to a multi-pixel APD readout of LYSO:Ce crystals

International Nuclear Information System (INIS)

Albuquerque, Edgar; Bexiga, Vasco; Bugalho, Ricardo; Carrico, Bruno; Ferreira, Claudia S.; Ferreira, Miguel; Godinho, Joaquim; Goncalves, Fernando; Leong, Carlos; Lousa, Pedro; Machado, Pedro; Moura, Rui; Neves, Pedro; Ortigao, Catarina; Piedade, Fernando; Pinheiro, Joao F.; Rego, Joel; Rivetti, Angelo; Rodrigues, Pedro; Silva, Jose C.

2009-01-01

In the framework of the Clear-PEM project for the construction of a high-resolution scanner for breast cancer imaging, a very compact and dense frontend electronics system has been developed for readout of multi-pixel S8550 Hamamatsu APDs. The frontend electronics are instrumented with a mixed-signal Application-Specific Integrated Circuit (ASIC), which incorporates 192 low-noise charge pre-amplifiers, shapers, analog memory cells and digital control blocks. Pulses are continuously stored in memory cells at clock frequency. Channels above a common threshold voltage are readout for digitization by off-chip free-sampling ADCs. The ASIC has a size of 7.3x9.8mm 2 and was implemented in a AMS 0.35μm CMOS technology. In this paper the experimental characterization of the Clear-PEM frontend ASIC, reading out multi-pixel APDs coupled to LYSO:Ce crystal matrices, is presented. The chips were mounted on a custom test board connected to six APD arrays and to the data acquisition system. Six 32-pixel LYSO:Ce crystal matrices coupled on both sides to APD arrays were readout by two test boards. All 384 channels were operational. The chip power consumption is 660 mW (3.4 mW per channel). A very stable behavior of the chip was observed, with an estimated ENC of 1200-1300e - at APD gain 100. The inter-channel noise dispersion and mean baseline variation is less than 8% and 0.5%, respectively. The spread in the gain between different channels is found to be 1.5%. Energy resolution of 16.5% at 511 keV and 12.8% at 662 keV has been measured. Timing measurements between the two APDs that readout the same crystal is extracted and compared with detailed Monte Carlo simulations. At 511 keV the measured single photon time RMS resolution is 1.30 ns, in very good agreement with the expected value of 1.34 ns.

Unconventional geometric logic gate in a strong-driving-assisted multi-mode cavity

International Nuclear Information System (INIS)

Chang-Ning, Pan; Di-Wu, Yang; Xue-Hui, Zhao; Mao-Fa, Fang

2010-01-01

We propose a scheme to implement an unconventional geometric logic gate separately in a two-mode cavity and a multi-mode cavity assisted by a strong classical driving field. The effect of the cavity decay is included in the investigation. The numerical calculation is carried out, and the result shows that our scheme is more tolerant to cavity decay than the previous one because the time consumed for finishing the logic gate is doubly reduced. (general)

Ultra-thin silicon (UTSi) on insulator CMOS transceiver and time-division multiplexed switch chips for smart pixel integration

Science.gov (United States)

Zhang, Liping; Sawchuk, Alexander A.

2001-12-01

We describe the design, fabrication and functionality of two different 0.5 micron CMOS optoelectronic integrated circuit (OEIC) chips based on the Peregrine Semiconductor Ultra-Thin Silicon on insulator technology. The Peregrine UTSi silicon- on-sapphire (SOS) technology is a member of the silicon-on- insulator (SOI) family. The low-loss synthetic sapphire substrate is optically transparent and has good thermal conductivity and coefficient of thermal expansion properties, which meet the requirements for flip-chip bonding of VCSELs and other optoelectronic input-output components. One chip contains transceiver and network components, including four channel high-speed CMOS transceiver modules, pseudo-random bit stream (PRBS) generators, a voltage controlled oscillator (VCO) and other test circuits. The transceiver chips can operate in both self-testing mode and networking mode. An on- chip clock and true-single-phase-clock (TSPC) D-flip-flop have been designed to generate a PRBS at over 2.5 Gb/s for the high-speed transceiver arrays to operate in self-testing mode. In the networking mode, an even number of transceiver chips forms a ring network through free-space or fiber ribbon interconnections. The second chip contains four channel optical time-division multiplex (TDM) switches, optical transceiver arrays, an active pixel detector and additional test devices. The eventual applications of these chips will require monolithic OEICs with integrated optical input and output. After fabrication and testing, the CMOS transceiver array dies will be packaged with 850 nm vertical cavity surface emitting lasers (VCSELs), and metal-semiconductor- metal (MSM) or GaAs p-i-n detector die arrays to achieve high- speed optical interconnections. The hybrid technique could be either wire bonding or flip-chip bonding of the CMOS SOS smart-pixel arrays with arrays of VCSELs and photodetectors onto an optoelectronic chip carrier as a multi-chip module (MCM).

Reverse-mode PSLC multi-plane optical see-through display for AR applications.

Science.gov (United States)

Liu, Shuxin; Li, Yan; Zhou, Pengcheng; Chen, Quanming; Su, Yikai

2018-02-05

In this paper we propose an optical see-through multi-plane display with reverse-mode polymer-stabilized liquid crystal (PSLC). Our design solves the problem of accommodation-vergence conflict with correct focus cues. In the reverse mode PSLC system, power consumption could be reduced to ~1/(N-1) of that in a normal mode system if N planes are displayed. The PSLC films fabricated in our experiment exhibit a low saturation voltage ~20 V rms , a high transparent-state transmittance (92%), and a fast switching time within 2 ms and polarization insensitivity. A proof-of-concept two-plane color display prototype and a four-plane monocolor display prototype were implemented.

A reconfigurable frequency-selective surface for dual-mode multi-band filtering applications

Science.gov (United States)

Majidzadeh, Maryam; Ghobadi, Changiz; Nourinia, Javad

2017-03-01

A reconfigurable single-layer frequency-selective surface (FSS) with dual-mode multi-band modes of operation is presented. The proposed structure is printed on a compact 10 × 10 mm2 FR4 substrate with the thickness of 1.6 mm. A simple square loop is printed on the front side while another one along with two defected vertical arms is deployed on the backside. To realise the reconfiguration, two pin diodes are embedded on the backside square loop. Suitable insertion of conductive elements along with pin diodes yields in dual-mode multi-band rejection of applicable in service frequency ranges. The first operating mode due to diodes' 'ON' state provides rejection of 2.4 GHz WLAN in 2-3 GHz, 5.2/5.8 GHz WLAN and X band in 5-12 GHz, and a part of Ku band in 13.9-16 GHz. In diodes 'OFF' state, the FSS blocks WLAN in 4-7.3 GHz, X band in 8-12.7 GHz as well as part of Ku band in 13.7-16.7 GHz. As well, high attenuation of incident waves is observed by a high shielding effectiveness (SE) in the blocked frequency bands. Also, a stable behaviour against different polarisations and angles of incidence is obtained. Comprehensive studies are conducted on a fabricated prototype to assess its performance from which encouraging results are obtained.

Development of a multi-mode hybrid electric bus

Energy Technology Data Exchange (ETDEWEB)

Shemmans, M.J. [Overland Custom Coach, Thorndale, ON (Canada); Bland, C. [BET Services Inc., Mississauga, ON (Canada)

2004-04-01

This paper describes the development of an energy efficient, low floor, 28 foot hybrid electric bus for use as an airport shuttle bus or other specialized transit operations. A multi-mode concept was also adopted to include the capability of operating in battery-only drive, engine-only drive or a range of hybrid electric drive modes. The electric drivetrain was powered by a battery pack or a combination of a battery pack and an internal combustion engine-powered electric generator. The participating companies in this project include Overland Custom Coach, BET Services Inc., Siemens and Transport Canada. The technical feasibility study was described with reference to duty cycles, performance issues, vehicle weight, mechanical drive issues, brakes, suspension, powertrain cooling, heating, ventilation, electrical system, batteries and control system. The commercial feasibility was also described in terms of capital and operating costs. Results of the prototype tests validate the possibilities of zero or reduced emission transit in real world applications. 25 tabs., 32 figs.

System aspects of the ILC-electronics and power pulsing

CERN Document Server

Götlicher, P

2007-01-01

The requirements for the electronics of an experiment at the international linear collider (ILC) are driven by the bunch structure of the accelerator - short trains (1ms) with bunch to bunch lag of 0.3μs interrupted by long empty intervals (199ms) - and the precision physics. Based on developments of the CALICEcollaboration a system for high granular dense calorimetry is presented. The talk covers the system aspect: — of compact sensors as Si-diodes and multi-pixel Geiger mode photo sensors, — of the electromechanics with components embedded into the PCB’s, — of integrating the functionality needed nearby the sensor into low power ASIC’s, — of a DAQ-chain, in which each channel triggers on its own and the data selection is installed into PC’s and — of calibrating the calorimeter. With the high number of 100 million channels the power consumption and cooling have to be investigated carefully. Calculations demonstrate, that active cooling inside the calorimeters can be avoided. But essential fo...

Electronics for the camera of the First G-APD Cherenkov Telescope (FACT) for ground based gamma-ray astronomy

International Nuclear Information System (INIS)

Anderhub, H; Biland, A; Boller, A; Braun, I; Commichau, V; Djambazov, L; Dorner, D; Gendotti, A; Grimm, O; Gunten, H P von; Hildebrand, D; Horisberger, U; Huber, B; Kim, K-S; Krähenbühl, T; Backes, M; Köhne, J-H; Krumm, B; Bretz, T; Farnier, C

2012-01-01

Within the FACT project, we construct a new type of camera based on Geiger-mode avalanche photodiodes (G-APDs). Compared to photomultipliers, G-APDs are more robust, need a lower operation voltage and have the potential of higher photon-detection efficiency and lower cost, but were never fully tested in the harsh environments of Cherenkov telescopes. The FACT camera consists of 1440 G-APD pixels and readout channels, based on the DRS4 (Domino Ring Sampler) analog pipeline chip and commercial Ethernet components. Preamplifiers, trigger system, digitization, slow control and power converters are integrated into the camera.

A four-port launcher for a multi-moded DLDS power distribution system

International Nuclear Information System (INIS)

Eppley, K.; Li, Z.; Miller, R.; Nantista, C.; Tantawi, S.

1998-06-01

The authors describe a structure for launching the TE 01 and both polarizations of TE 12 modes into a highly overmoded low loss circular waveguide providing remote transmission for a multi-moded Delay Line Distribution System (DLDS). The power from four sources is delivered to four structure ports by rectangular waveguide, and the mode for each pulse subsection is selected by varying the relative phases of the sources. The four ports symmetrically feed a section of waveguide with a fourfold symmetric four-leaf clover-like (or quatrefoil) cross section, dimensioned so as to propagate only four TE modes, characterized as 0, π/2 (two polarizations), and π modes. The 0 and π/2 modes are well matched, the π mode only moderately so. A low loss taper transforms the initial cross section to a circular cross section; the 0 mode transforming to TE 01 , the π/2 to TE 11 , the π to TE 21 , all with negligible mode conversion. A sausage type mode transducer then converts TE 11 to TE 12 (a lower loss mode), and the diameter is then expanded to the full ∼five inch diameter of the delay line. A separate structure to divert power from the last pulse subsection to the local group of accelerator structures is required

CMOS Active-Pixel Image Sensor With Intensity-Driven Readout

Science.gov (United States)

Langenbacher, Harry T.; Fossum, Eric R.; Kemeny, Sabrina

1996-01-01

Proposed complementary metal oxide/semiconductor (CMOS) integrated-circuit image sensor automatically provides readouts from pixels in order of decreasing illumination intensity. Sensor operated in integration mode. Particularly useful in number of image-sensing tasks, including diffractive laser range-finding, three-dimensional imaging, event-driven readout of sparse sensor arrays, and star tracking.

Development of multi-pixel x-ray source using oxide-coated cathodes.

Science.gov (United States)

Kandlakunta, Praneeth; Pham, Richard; Khan, Rao; Zhang, Tiezhi

2017-07-07

Multiple pixel x-ray sources facilitate new designs of imaging modalities that may result in faster imaging speed, improved image quality, and more compact geometry. We are developing a high-brightness multiple-pixel thermionic emission x-ray (MPTEX) source based on oxide-coated cathodes. Oxide cathodes have high emission efficiency and, thereby, produce high emission current density at low temperature when compared to traditional tungsten filaments. Indirectly heated micro-rectangular oxide cathodes were developed using carbonates, which were converted to semiconductor oxides of barium, strontium, and calcium after activation. Each cathode produces a focal spot on an elongated fixed anode. The x-ray beam ON and OFF control is performed by source-switching electronics, which supplies bias voltage to the cathode emitters. In this paper, we report the initial performance of the oxide-coated cathodes and the MPTEX source.

Hydrological Climate Classification: Can We Improve on Köppen-Geiger?

Science.gov (United States)

Knoben, W.; Woods, R. A.; Freer, J. E.

2017-12-01

Classification is essential in the study of complex natural systems, yet hydrology so far has no formal way to structure the climate forcing which underlies hydrologic response. Various climate classification systems can be borrowed from other disciplines but these are based on different organizing principles than a hydrological classification might use. From gridded global data we calculate a gridded aridity index, an aridity seasonality index and a rain-vs-snow index, which we use to cluster global locations into climate groups. We then define the membership degree of nearly 1100 catchments to each of our climate groups based on each catchment's climate and investigate the extent to which streamflow responses within each climate group are similar. We compare this climate classification approach with the often-used Köppen-Geiger classification, using statistical tests based on streamflow signature values. We find that three climate indices are sufficient to distinguish 18 different climate types world-wide. Climates tend to change gradually in space and catchments can thus belong to multiple climate groups, albeit with different degrees of membership. Streamflow responses within a climate group tend to be similar, regardless of the catchments' geographical proximity. A Wilcoxon two-sample test based on streamflow signature values for each climate group shows that the new classification can distinguish different flow regimes using this classification scheme. The Köppen-Geiger approach uses 29 climate classes but is less able to differentiate streamflow regimes. Climate forcing exerts a strong control on typical hydrologic response and both change gradually in space. This makes arbitrary hard boundaries in any classification scheme difficult to defend. Any hydrological classification should thus acknowledge these gradual changes in forcing. Catchment characteristics (soil or vegetation type, land use, etc) can vary more quickly in space than climate does, which

A micropixel avalanche phototransistor for time of flight measurements

Energy Technology Data Exchange (ETDEWEB)

Sadigov, A., E-mail: saazik@yandex.ru [National Nuclear Research Center, Baku (Azerbaijan); Institute of Radiation Problems, Baku (Azerbaijan); Suleymanov, S. [National Nuclear Research Center, Baku (Azerbaijan); Institute of Radiation Problems, Baku (Azerbaijan); Ahmadov, F. [National Nuclear Research Center, Baku (Azerbaijan); Ahmadov, G. [National Nuclear Research Center, Baku (Azerbaijan); Joint Institute for Nuclear Research, Dubna (Russian Federation); Abdullayev, K. [National Aviation Academy, Baku (Azerbaijan); Akberov, R. [National Nuclear Research Center, Baku (Azerbaijan); Institute of Radiation Problems, Baku (Azerbaijan); Heydarov, N. [National Nuclear Research Center, Baku (Azerbaijan); Madatov, R. [Institute of Radiation Problems, Baku (Azerbaijan); Mukhtarov, R. [National Aviation Academy, Baku (Azerbaijan); Nazarov, M.; Valiyev, R. [National Nuclear Research Center, Baku (Azerbaijan)

2017-02-11

This paper presents results of studies of the silicon based new micropixel avalanche phototransistor (MAPT). MAPT is a modification of well-known silicon photomultipliers (SiPMs) and differs since each photosensitive pixel of the MAPT operates in Geiger mode and comprises an individual micro-transistor operating in binary mode. This provides a high amplitude single photoelectron signal with significantly shorter rise time. The obtained results are compared with appropriate parameters of known SiPMs. - Highlights: • A new photo detector – micropixel avalanche phototransistor was developed. • MAPT has a matrix of microtransistors with fast output. • In these modules the duration of the leading edge of the signal from the photodetectors are not worse than 50–100 ps.

Gossipo-3 A prototype of a Front-End Pixel Chip for Read-Out of Micro-Pattern Gas Detectors

CERN Document Server

Brezina, Christpoh; van der Graaf, Haryy; Gromov, Vladimir; Kluit, Ruud; Kruth, Andre; Zappon, Francesco

2009-01-01

In a joint effort of Nikhef (Amsterdam) and the University of Bonn, the Gossipo-3 integrated circuit (IC) has been developed. This circuit is a prototype of a chip dedicated for read-out of various types of position sensitive Micro-Pattern Gas detectors (MPGD). The Gossipo-3 is defined as a set of building blocks to be used in a future highly granulated (60 μm) chip. The pixel circuit can operate in two modes. In Time mode every readout pixel measures the hit arrival time and the charge deposit. For this purpose it has been equipped with a high resolution TDC (1.7 ns) covering dynamic range up to 102 μs. Charge collected by the pixel will be measured using Time-over- Threshold method in the range from 400 e- to 28000 e- with accuracy of 200 e- (standard deviation). In Counting mode every pixel operates as a 24-bit counter, counting the number of incoming hits. The circuit is also optimized to operate at low power consumption (100 mW/cm2) that is required to avoid the need for massive power transport and coo...

Extraction of design rules from multi-objective design exploration (MODE) using rough set theory

International Nuclear Information System (INIS)

Obayashi, Shigeru

2011-01-01

Multi-objective design exploration (MODE) and its application for design rule extraction are presented. MODE reveals the structure of design space from the trade-off information. The self-organizing map (SOM) is incorporated into MODE as a visual data-mining tool for design space. SOM divides the design space into clusters with specific design features. The sufficient conditions for belonging to a cluster of interest are extracted using rough set theory. The resulting MODE was applied to the multidisciplinary wing design problem, which revealed a cluster of good designs, and we extracted the design rules of such designs successfully.

Damage classification of pipelines under water flow operation using multi-mode actuated sensing technology

International Nuclear Information System (INIS)

Lee, Changgil; Park, Seunghee

2011-01-01

In a structure, several types of damage can occur, ranging from micro-cracking to corrosion or loose bolts. This makes identifying the damage difficult with a single mode of sensing. Therefore, a multi-mode actuated sensing system is proposed based on a self-sensing circuit using a piezoelectric sensor. In self-sensing-based multi-mode actuated sensing, one mode provides a wide frequency-band structural response from the self-sensed impedance measurement and the other mode provides a specific frequency-induced structural wavelet response from the self-sensed guided wave measurement. In this experimental study, a pipeline system under water flow operation was examined to verify the effectiveness and robustness of the proposed structural health monitoring approach. Different types of structural damage were inflicted artificially on the pipeline system. To classify the multiple types of structural damage, supervised learning-based statistical pattern recognition was implemented by composing a three-dimensional space using the damage indices extracted from the impedance and guided wave features as well as temperature variations. For a more systematic damage classification, several control parameters were optimized to determine an optimal decision boundary for the supervised learning-based pattern recognition. Further research issues are also discussed for real-world implementations of the proposed approach

Monte Carlo design and simulation of a grid-type multi-layer pixel collimator for radiotherapy: feasibility study

Energy Technology Data Exchange (ETDEWEB)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae-Suk [The Catholic University of Korea, Seoul (Korea, Republic of)

2014-05-15

In order to confirm the possibility of field application of a different type collimator with a multileaf collimator (MLC), we constructed a grid-type multi-layer pixel collimator (GTPC) by using a Monte Carlo n-particle simulation (MCNPX). In this research, a number of factors related to the performance of the GPTC were evaluated using simulated output data of a basic MLC model. A layer was comprised of a 1024-pixel collimator (5.0 x 5.0 mm{sup 2}) which could operate individually as a grid-type collimator (32 x 32). A 30-layer collimator was constructed for a specific portal form to pass radiation through the opening and closing of each pixel cover. The radiation attenuation level and the leakage were compared between the GTPC modality simulation and MLC modeling (tungsten, 17.50 g/cm{sup 3}, 5.0 x 70.0 x 160.0 mm{sup 3}) currently used for a radiation field. Comparisons of the portal imaging, the lateral dose profile from a virtual water phantom, the dependence of the performance on the increase in the number of layers, the radiation intensity modulation verification, and the geometric error between the GTPC and the MLC were done using the MCNPX simulation data. From the simulation data, the intensity modulation of the GTPC showed a faster response than the MLC's (29.6%). In addition, the agreement between the doses that should be delivered to the target region was measured as 97.0%, and the GTPC system had an error below 0.01%, which is identical to that of MLC. A Monte Carlo simulation of the GTPC could be useful for verification of application possibilities. Because the line artifact is caused by the grid frame and the folded cover, a lineal dose transfer type is chosen for the operation of this system. However, the result of GTPC's performance showed that the methods of effective intensity modulation and the specific geometric beam shaping differed with the MLC modality.

Monte Carlo design and simulation of a grid-type multi-layer pixel collimator for radiotherapy: Feasibility study

Science.gov (United States)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae Suk

2014-05-01

In order to confirm the possibility of field application of a different type collimator with a multileaf collimator (MLC), we constructed a grid-type multi-layer pixel collimator (GTPC) by using a Monte Carlo n-particle simulation (MCNPX). In this research, a number of factors related to the performance of the GPTC were evaluated using simulated output data of a basic MLC model. A layer was comprised of a 1024-pixel collimator (5.0 × 5.0 mm2) which could operate individually as a grid-type collimator (32 × 32). A 30-layer collimator was constructed for a specific portal form to pass radiation through the opening and closing of each pixel cover. The radiation attenuation level and the leakage were compared between the GTPC modality simulation and MLC modeling (tungsten, 17.50 g/cm3, 5.0 × 70.0 × 160.0 mm3) currently used for a radiation field. Comparisons of the portal imaging, the lateral dose profile from a virtual water phantom, the dependence of the performance on the increase in the number of layers, the radiation intensity modulation verification, and the geometric error between the GTPC and the MLC were done using the MCNPX simulation data. From the simulation data, the intensity modulation of the GTPC showed a faster response than the MLC's (29.6%). In addition, the agreement between the doses that should be delivered to the target region was measured as 97.0%, and the GTPC system had an error below 0.01%, which is identical to that of MLC. A Monte Carlo simulation of the GTPC could be useful for verification of application possibilities. Because the line artifact is caused by the grid frame and the folded cover, a lineal dose transfer type is chosen for the operation of this system. However, the result of GTPC's performance showed that the methods of effective intensity modulation and the specific geometric beam shaping differed with the MLC modality.

Monte Carlo design and simulation of a grid-type multi-layer pixel collimator for radiotherapy: feasibility study

International Nuclear Information System (INIS)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae-Suk

2014-01-01

In order to confirm the possibility of field application of a different type collimator with a multileaf collimator (MLC), we constructed a grid-type multi-layer pixel collimator (GTPC) by using a Monte Carlo n-particle simulation (MCNPX). In this research, a number of factors related to the performance of the GPTC were evaluated using simulated output data of a basic MLC model. A layer was comprised of a 1024-pixel collimator (5.0 x 5.0 mm 2 ) which could operate individually as a grid-type collimator (32 x 32). A 30-layer collimator was constructed for a specific portal form to pass radiation through the opening and closing of each pixel cover. The radiation attenuation level and the leakage were compared between the GTPC modality simulation and MLC modeling (tungsten, 17.50 g/cm 3 , 5.0 x 70.0 x 160.0 mm 3 ) currently used for a radiation field. Comparisons of the portal imaging, the lateral dose profile from a virtual water phantom, the dependence of the performance on the increase in the number of layers, the radiation intensity modulation verification, and the geometric error between the GTPC and the MLC were done using the MCNPX simulation data. From the simulation data, the intensity modulation of the GTPC showed a faster response than the MLC's (29.6%). In addition, the agreement between the doses that should be delivered to the target region was measured as 97.0%, and the GTPC system had an error below 0.01%, which is identical to that of MLC. A Monte Carlo simulation of the GTPC could be useful for verification of application possibilities. Because the line artifact is caused by the grid frame and the folded cover, a lineal dose transfer type is chosen for the operation of this system. However, the result of GTPC's performance showed that the methods of effective intensity modulation and the specific geometric beam shaping differed with the MLC modality.

The Dosepix detector—an energy-resolving photon-counting pixel detector for spectrometric measurements

CERN Document Server

Zang, A; Ballabriga, R; Bisello, F; Campbell, M; Celi, J C; Fauler, A; Fiederle, M; Jensch, M; Kochanski, N; Llopart, X; Michel, N; Mollenhauer, U; Ritter, I; Tennert, F; Wölfel, S; Wong, W; Michel, T

2015-01-01

The Dosepix detector is a hybrid photon-counting pixel detector based on ideas of the Medipix and Timepix detector family. 1 mm thick cadmium telluride and 300 μm thick silicon were used as sensor material. The pixel matrix of the Dosepix consists of 16 x 16 square pixels with 12 rows of (200 μm)2 and 4 rows of (55 μm)2 sensitive area for the silicon sensor layer and 16 rows of pixels with 220 μm pixel pitch for CdTe. Besides digital energy integration and photon-counting mode, a novel concept of energy binning is included in the pixel electronics, allowing energy-resolved measurements in 16 energy bins within one acquisition. The possibilities of this detector concept range from applications in personal dosimetry and energy-resolved imaging to quality assurance of medical X-ray sources by analysis of the emitted photon spectrum. In this contribution the Dosepix detector, its response to X-rays as well as spectrum measurements with Si and CdTe sensor layer are presented. Furthermore, a first evaluation wa...

Radiation hardness of CMS pixel barrel modules

CERN Document Server

Rohe, T; Erdmann, W; Kästli, H C; Khalatyan, S; Meier, B; Radicci, V; Sibille, J

2010-01-01

Pixel detectors are used in the innermost part of the multi purpose experiments at LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has thoroughly been tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6E14 Neq and with 21 GeV protons at CERN up to 5E15 Neq. After irradiation the response of the system to beta particles from a Sr-90 source w...

A design of optical modulation system with pixel-level modulation accuracy

Science.gov (United States)

Zheng, Shiwei; Qu, Xinghua; Feng, Wei; Liang, Baoqiu

2018-01-01

Vision measurement has been widely used in the field of dimensional measurement and surface metrology. However, traditional methods of vision measurement have many limits such as low dynamic range and poor reconfigurability. The optical modulation system before image formation has the advantage of high dynamic range, high accuracy and more flexibility, and the modulation accuracy is the key parameter which determines the accuracy and effectiveness of optical modulation system. In this paper, an optical modulation system with pixel level accuracy is designed and built based on multi-points reflective imaging theory and digital micromirror device (DMD). The system consisted of digital micromirror device, CCD camera and lens. Firstly we achieved accurate pixel-to-pixel correspondence between the DMD mirrors and the CCD pixels by moire fringe and an image processing of sampling and interpolation. Then we built three coordinate systems and calculated the mathematic relationship between the coordinate of digital micro-mirror and CCD pixels using a checkerboard pattern. A verification experiment proves that the correspondence error is less than 0.5 pixel. The results show that the modulation accuracy of system meets the requirements of modulation. Furthermore, the high reflecting edge of a metal circular piece can be detected using the system, which proves the effectiveness of the optical modulation system.

Applications of pixellated GaAs X-ray detectors in a synchrotron radiation beam

CERN Document Server

Watt, J; Campbell, M; Mathieson, K; Mikulec, B; O'Shea, V; Passmore, M S; Schwarz, C; Smith, K M; Whitehill, C

2001-01-01

Hybrid semiconductor pixel detectors are being investigated as imaging devices for radiography and synchrotron radiation beam applications. Based on previous work in the CERN RD19 and the UK IMPACT collaborations, a photon counting GaAs pixel detector (PCD) has been used in an X-ray powder diffraction experiment. The device consists of a 200 mu m thick SI-LEC GaAs detector patterned in a 64*64 array of 170 mu m pitch square pixels, bump-bonded to readout electronics operating in single photon counting mode. Intensity peaks in the powder diffraction pattern of KNbO/sub 3/ have been resolved and compared with results using the standard scintillator, and a PCD predecessor (the Omega 3). The PCD shows improved speed, dynamic range, 2-D information and comparable spatial resolution to the standard scintillator based systems. It also overcomes the severe dead time limitations of the Omega 3 by using a shutter based acquisition mode. A brief demonstration of the possibilities of the system for dental radiography and...

Multi-mode-multi-state quantum dynamics of key five-membered heterocycles: spectroscopy and ultrafast internal conversion

International Nuclear Information System (INIS)

Koeppel, H.; Gromov, E.V.; Trofimov, A.B.

2004-01-01

The multi-mode and multi-state vibronic interactions in the heterocyclic molecules furan, pyrrole, thiophene and their radical cations are investigated theoretically, employing a linear vibronic coupling scheme. The underlying system parameters are determined from large-scale ab initio computations. Previous time-independent dynamical calculations on the radical cations are extended by wave-packet propagations (using the MCTDH method) confirming the strong nonadiabatic coupling effects. For the singlet excited states of furan and thiophene quantum dynamical calculations are presented which go beyond the two-state approximation frequently applied in the literature. The characteristic spectral structures are well reproduced, especially in the case of furan. The implications of these results on the photochemical reaction dynamics of these species are discussed

Readout of a 176 pixel FDM system for SAFARI TES arrays

Science.gov (United States)

Hijmering, R. A.; den Hartog, R.; Ridder, M.; van der Linden, A. J.; van der Kuur, J.; Gao, J. R.; Jackson, B.

2016-07-01

In this paper we present the results of our 176-pixel prototype of the FDM readout system for SAFARI, a TES-based focal-plane instrument for the far-IR SPICA mission. We have implemented the knowledge obtained from the detailed study on electrical crosstalk reported previously. The effect of carrier leakage is reduced by a factor two, mutual impedance is reduced to below 1 nH and mutual inductance is removed. The pixels are connected in stages, one quarter of the array half of the array and the full array, to resolve intermediate technical issues. A semi-automated procedure was incorporated to find all optimal settings for all pixels. And as a final step the complete array has been connected and 132 pixels have been read out simultaneously within the frequency range of 1-3.8MHz with an average frequency separation of 16kHz. The noise was found to be detector limited and was not affected by reading out all pixels in a FDM mode. With this result the concept of using FDM for multiplexed bolometer read out for the SAFARI instrument has been demonstrated.

Synchrotron applications of pixel and strip detectors at Diamond Light Source

International Nuclear Information System (INIS)

Marchal, J.; Tartoni, N.; Nave, C.

2009-01-01

A wide range of position-sensitive X-ray detectors have been commissioned on the synchrotron X-ray beamlines operating at the Diamond Light Source in UK. In addition to mature technologies such as image-plates, CCD-based detectors, multi-wire and micro-strip gas detectors, more recent detectors based on semiconductor pixel or strip sensors coupled to CMOS read-out chips are also in use for routine synchrotron X-ray diffraction and scattering experiments. The performance of several commercial and developmental pixel/strip detectors for synchrotron studies are discussed with emphasis on the image quality achieved with these devices. Examples of pixel or strip detector applications at Diamond Light Source as well as the status of the commissioning of these detectors on the beamlines are presented. Finally, priorities and ideas for future developments are discussed.

Multiparameter-dependent spontaneous emission in PbSe quantum dot-doped liquid-core multi-mode fiber

International Nuclear Information System (INIS)

Zhang, Lei; Zhang, Yu; Wu, Hua; Zhang, Tieqiang; Gu, Pengfei; Chu, Hairong; Cui, Tian; Wang, Yiding; Zhang, Hanzhuang; Zhao, Jun; Yu, William W.

2013-01-01

A theoretical model was established in this paper to analyze the properties of 3.50 and 4.39 nm PbSe quantum dot-doped liquid-core multi-mode fiber. This model was applicable to both single- and multi-mode fiber. The three-level system-based light-propagation equations and rate equations were used to calculate the guided spontaneous emission spectra. Considering the multi-mode in the fiber, the normalized intensity distribution of transversal model was improved and simplified. The detailed calculating results were thus obtained and explained using the above-mentioned model. The redshift of the peak position and the evolution of the emission power were observed and analyzed considering the influence of the fiber length, fiber diameter, doping concentration, and the pump power. The redshift increased with the increases of fiber length, fiber diameter, and doping concentration. The optimal fiber length, fiber diameter, and doping concentration were analyzed and confirmed, and the related spontaneous emission power was obtained. Besides, the normalized emission intensity increased with the increase of pump power in a nearly linear way. The calculating results fitted well to the experimental data

Multi-spectral confocal microendoscope for in-vivo imaging

Science.gov (United States)

Rouse, Andrew Robert

The concept of in-vivo multi-spectral confocal microscopy is introduced. A slit-scanning multi-spectral confocal microendoscope (MCME) was built to demonstrate the technique. The MCME employs a flexible fiber-optic catheter coupled to a custom built slit-scan confocal microscope fitted with a custom built imaging spectrometer. The catheter consists of a fiber-optic imaging bundle linked to a miniature objective and focus assembly. The design and performance of the miniature objective and focus assembly are discussed. The 3mm diameter catheter may be used on its own or routed though the instrument channel of a commercial endoscope. The confocal nature of the system provides optical sectioning with 3mum lateral resolution and 30mum axial resolution. The prism based multi-spectral detection assembly is typically configured to collect 30 spectral samples over the visible chromatic range. The spectral sampling rate varies from 4nm/pixel at 490nm to 8nm/pixel at 660nm and the minimum resolvable wavelength difference varies from 7nm to 18nm over the same spectral range. Each of these characteristics are primarily dictated by the dispersive power of the prism. The MCME is designed to examine cellular structures during optical biopsy and to exploit the diagnostic information contained within the spectral domain. The primary applications for the system include diagnosis of disease in the gastro-intestinal tract and female reproductive system. Recent data from the grayscale imaging mode are presented. Preliminary multi-spectral results from phantoms, cell cultures, and excised human tissue are presented to demonstrate the potential of in-vivo multi-spectral imaging.

Performances of Dose Measurement of Commercial Electronic Dosimeters using Geiger Muller Tube and PIN Diode

Energy Technology Data Exchange (ETDEWEB)

Yoo, Hyunjun; Kim, Chankyu; Kim, Yewon; Kim, Giyoon; Cho, Gyuseong [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-05-15

There are two categories in personal dosimeters, one is passive type dosimeter such as TLD (thermoluminescence dosimeter) and the other is active type dosimeter such as electronic dosimeter can show radiation dose immediately while TLD needs long time to readout its data by heating process. For improving the reliability of measuring dose for any energy of radiations, electronic dosimeter uses energy filter by metal packaging its detector using aluminum or copper, but measured dose of electronic dosimeter with energy filter cannot be completely compensated in wide radiation energy region. So, in this paper, we confirmed the accuracy of dose measurement of two types of commercial EPDs using Geiger Muller tube and PIN diode with CsI(Tl) scintillator in three different energy of radiation field. The experiment results for Cs-137 was almost similar with calculation value in the results of both electronic dosimeters, but, the other experiment values with Na-22 and Co-60 had higher error comparing with Cs-137. These results were caused by optimization of their energy filters. The optimization was depending on its thickness of energy filter. So, the electronic dosimeters have to optimizing the energy filter for increasing the accuracy of dose measurement or the electronic dosimeter using PIN diode with CsI(Tl) scintillator uses the multi-channel discriminator for using its energy information.

The Belle II DEPFET pixel detector

Energy Technology Data Exchange (ETDEWEB)

Moser, Hans-Günther, E-mail: moser@mpp.mpg.de

2016-09-21

The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55–60) μm in the first layer and between 50 μm×(70–85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the ‘internal gate’ modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X{sub 0}). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO{sub 2} system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

Geiger Muller (GM) detector as online monitor: an experimental study

International Nuclear Information System (INIS)

Jayan, M.P.; Pawar, V.J.; Krishnakumar, P.; Sureshkumar, M.

2014-01-01

Monitoring the inadvertent release of radioactivity into otherwise inactive liquid streams is a common requirement in nuclear industry. In addition to conventional off-line sampling and measurement methods, nuclear facilities usually uses online methods to get real-time detection of activity contents in process cooling water lines and steam condensate lines. Due to its simplicity, ruggedness and cost effectiveness, Geiger Muller counter is obviously the first choice for online application. Though GM based monitors for such online application were in industrial use for a long time, practical data on the response of the detector with respect low level activities in the effluents is scarce in literature. This work was carried out to fill this information gap. The data generated in these experiments may be useful in giving a realistic interpretation of the response of the existing monitors and setting up their alarm limits

Potassium analysis by beta counting using a Geiger-Mueller system

International Nuclear Information System (INIS)

Espana, E.; Beneitez, P.; Calderon, T.

1993-01-01

A technique for quantitative analysis of different soils, ceramics, feldspars and natural halide samples is presented, based on the measurement of β-activities using a Geiger-Mueller system. The system was calibrated with KCl, KC 8 H 5 O 4 , KNO 3 and K 2 SO 4 standards and a potassium content of 1% yields a net β-count rate (background subtracted) of about 55 cph. Precision values of less than ±0.4% K can be achieved in counting times of about 4 hours. The results agree with those obtained by means of other more common analytical methods such as flame photometry, atomic absorption and γ-spectrometry. In comparison with these methods, this approach is direct, precise and non-destructive, because the samples do not require prior treatment. (author) 16 refs.; 2 figs.; 6 tabs

A Concept of Multi-Mode High Spectral Resolution Lidar Using Mach-Zehnder Interferometer

Directory of Open Access Journals (Sweden)

Jin Yoshitaka

2016-01-01

Full Text Available In this paper, we present the design of a High Spectral Resolution Lidar (HSRL using a laser that oscillates in a multi-longitudinal mode. Rayleigh and Mie scattering components are separated using a Mach-Zehnder Interferometer (MZI with the same free spectral range (FSR as the transmitted laser. The transmitted laser light is measured as a reference signal with the same MZI. By scanning the MZI periodically with a scanning range equal to the mode spacing, we can identify the maximum Mie and the maximum Rayleigh signals using the reference signal. The cross talk due to the spectral width of each laser mode can also be estimated.

Multi-class Mode of Action Classification of Toxic Compounds Using Logic Based Kernel Methods.

Science.gov (United States)

Lodhi, Huma; Muggleton, Stephen; Sternberg, Mike J E

2010-09-17

Toxicity prediction is essential for drug design and development of effective therapeutics. In this paper we present an in silico strategy, to identify the mode of action of toxic compounds, that is based on the use of a novel logic based kernel method. The technique uses support vector machines in conjunction with the kernels constructed from first order rules induced by an Inductive Logic Programming system. It constructs multi-class models by using a divide and conquer reduction strategy that splits multi-classes into binary groups and solves each individual problem recursively hence generating an underlying decision list structure. In order to evaluate the effectiveness of the approach for chemoinformatics problems like predictive toxicology, we apply it to toxicity classification in aquatic systems. The method is used to identify and classify 442 compounds with respect to the mode of action. The experimental results show that the technique successfully classifies toxic compounds and can be useful in assessing environmental risks. Experimental comparison of the performance of the proposed multi-class scheme with the standard multi-class Inductive Logic Programming algorithm and multi-class Support Vector Machine yields statistically significant results and demonstrates the potential power and benefits of the approach in identifying compounds of various toxic mechanisms. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gain analysis of higher-order-mode amplification in a dielectric-implanted multi-beam traveling wave structure

Energy Technology Data Exchange (ETDEWEB)

Gee, Anthony; Shin, Young-Min

2013-01-01

A multi-beam traveling wave amplifier designed with an overmoded staggered double grating array was examined by small signal analysis combined with simulation. Eigenmode and S-parameter analyses show that the 2cm long slow wave structure (SWS) has 1-5dB insertion loss over the passband (TM31 mode) with ~28% cold bandwidth. Analytic gain calculation indicates that in the SWS, TM31-mode is amplified with 15–20 dB/beam at 64–84GHz with three elliptical beams of 10kV and 150mA/beam, which was compared with particle-in-cell (PIC) simulations. PIC analysis on the analysis of instability with zero-input driving excitations demonstrated that background noises and non-operating lower order modes are noticeably suppressed by implanting equidistant dielectric absorbers; the overmoded structure only allowed the desired 3rd order mode to propagate in the structure. The designed circuit structure can be widely applied to multi-beam devices for high power RF generation.

Gain analysis of higher-order-mode amplification in a dielectric-implanted multi-beam traveling wave structure

International Nuclear Information System (INIS)

Gee, Anthony; Shin, Young-Min

2013-01-01

A multi-beam traveling wave amplifier designed with an overmoded staggered double grating array was examined by small signal analysis combined with simulation. Eigenmode and S-parameter analyses show that the 2 cm long slow wave structure (SWS) has 1–5 dB insertion loss over the passband (TM 31 mode) with ∼28% cold bandwidth. Analytic gain calculation indicates that in the SWS, TM 31 -mode is amplified with 15–20 dB/beam at 64–84 GHz with three elliptical beams of 10 kV and 150 mA/beam, which was compared with particle-in-cell (PIC) simulations. PIC analysis on the analysis of instability with zero-input driving excitations demonstrated that background noises and non-operating lower order modes are noticeably suppressed by implanting equidistant dielectric absorbers; the overmoded structure only allowed the desired 3rd order mode to propagate in the structure. The designed circuit structure can be widely applied to multi-beam devices for high power RF generation

PET image reconstruction with rotationally symmetric polygonal pixel grid based highly compressible system matrix

International Nuclear Information System (INIS)

Yu Yunhan; Xia Yan; Liu Yaqiang; Wang Shi; Ma Tianyu; Chen Jing; Hong Baoyu

2013-01-01

To achieve a maximum compression of system matrix in positron emission tomography (PET) image reconstruction, we proposed a polygonal image pixel division strategy in accordance with rotationally symmetric PET geometry. Geometrical definition and indexing rule for polygonal pixels were established. Image conversion from polygonal pixel structure to conventional rectangular pixel structure was implemented using a conversion matrix. A set of test images were analytically defined in polygonal pixel structure, converted to conventional rectangular pixel based images, and correctly displayed which verified the correctness of the image definition, conversion description and conversion of polygonal pixel structure. A compressed system matrix for PET image recon was generated by tap model and tested by forward-projecting three different distributions of radioactive sources to the sinogram domain and comparing them with theoretical predictions. On a practical small animal PET scanner, a compress ratio of 12.6:1 of the system matrix size was achieved with the polygonal pixel structure, comparing with the conventional rectangular pixel based tap-mode one. OS-EM iterative image reconstruction algorithms with the polygonal and conventional Cartesian pixel grid were developed. A hot rod phantom was detected and reconstructed based on these two grids with reasonable time cost. Image resolution of reconstructed images was both 1.35 mm. We conclude that it is feasible to reconstruct and display images in a polygonal image pixel structure based on a compressed system matrix in PET image reconstruction. (authors)

Das Thema “Altern” in Arno Geigers Roman «Alles über Sally»

Directory of Open Access Journals (Sweden)

Meike Dackweiler

2013-11-01

Full Text Available Alles über Sally (All about Sally is the fifth novel of the successful Austrian author Arno Geiger. While it was both praised and criticized for being a contemporary adaption of the adultery novel, little importance was attached to the theme of ageing, which pervades the whole novel. Moreover, adulterous female characters over fifty are rare in contemporary German literature. Given these premises, this essay examines the composition of the ageing characters in the novel and provides a discussion of the social construction of images of ageing.

ATLAS SemiConductor Tracker and Pixel Detector: Status and Performance

CERN Document Server

Reeves, K; The ATLAS collaboration

2012-01-01

The Semi-Conductor Tracker (SCT) and the Pixel Detector are the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is a silicon strip detector and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICS ABCD3TA, working in the binary readout mode. The Pixel Detector consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In the talk the current status of the SCT and Pixel Detector will be reviewed. We will report on the operation of the detectors including an overview of the issues we encountered and the observation of significant increases in leakage currents (as expected) from bulk ...

A multi-level maintenance policy for a multi-component and multifailure mode system with two independent failure modes

International Nuclear Information System (INIS)

Zhu, Wenjin; Fouladirad, Mitra; Bérenguer, Christophe

2016-01-01

This paper studies the maintenance modelling of a multi-component system with two independent failure modes with imperfect prediction signal in the context of a system of systems. Each individual system consists of multiple series components and the failure modes of all the components are divided into two classes due to their consequences: hard failure and soft failure, where the former causes system failure while the later results in inferior performance (production reduction) of system. Besides, the system is monitored and can be alerted by imperfect prediction signal before hard failure. Based on an illustration example of offshore wind farm, in this paper three maintenance strategies are considered: periodic routine, reactive and opportunistic maintenance. The periodic routine maintenance is scheduled at fixed period for each individual system in the perspective of system of systems. Between two successive routine maintenances, the reactive maintenance is instructed by the imperfect prediction signal according to two criterion proposed in this study for the system components. Due to the high setup cost and practical restraints of implementing maintenance activities, both routine and reactive maintenance can create the opportunities of maintenance for the other components of an individual system. The life cycle of the system and the cost of the proposed maintenance policies are analytically derived. Restrained by the complexity from both the system failure modelling and maintenance strategies, the performances and application scope of the proposed maintenance model are evaluated by numerical simulations. - Highlights: • We study the life behavior of a complex system with two failure modes. • We consider the imperfect prediction signal of potential failure by monitoring. • We propose an integrated maintenance policy with three levels based on wind turbine. • We derive the mathematical cost formulations for the proposed maintenance policy.

Improving Land Use/Land Cover Classification by Integrating Pixel Unmixing and Decision Tree Methods

Directory of Open Access Journals (Sweden)

Chao Yang

2017-11-01

Full Text Available Decision tree classification is one of the most efficient methods for obtaining land use/land cover (LULC information from remotely sensed imageries. However, traditional decision tree classification methods cannot effectively eliminate the influence of mixed pixels. This study aimed to integrate pixel unmixing and decision tree to improve LULC classification by removing mixed pixel influence. The abundance and minimum noise fraction (MNF results that were obtained from mixed pixel decomposition were added to decision tree multi-features using a three-dimensional (3D Terrain model, which was created using an image fusion digital elevation model (DEM, to select training samples (ROIs, and improve ROI separability. A Landsat-8 OLI image of the Yunlong Reservoir Basin in Kunming was used to test this proposed method. Study results showed that the Kappa coefficient and the overall accuracy of integrated pixel unmixing and decision tree method increased by 0.093% and 10%, respectively, as compared with the original decision tree method. This proposed method could effectively eliminate the influence of mixed pixels and improve the accuracy in complex LULC classifications.

Diamond Pixel Detectors

International Nuclear Information System (INIS)

Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Doroshenko, J.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foster, J.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Gobbi, B.; Grim, G.P.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Lander, R.; Logiudice, A.; Lu, R.; Lynne, L.M.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Perera, L.; Pirollo, S.; Plano, R.; Procario, M.; Riester, J.L.; Roe, S.; Rott, C.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Zoeller, M.

2001-01-01

Diamond based pixel detectors are a promising radiation-hard technology for use at the LHC. We present first results on a CMS diamond pixel sensor. With a threshold setting of 2000 electrons, an average pixel efficiency of 78% was obtained for normally incident minimum ionizing particles

Diamond Pixel Detectors

Energy Technology Data Exchange (ETDEWEB)

Adam, W.; Berdermann, E.; Bergonzo, P.; Bertuccio, G.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Doroshenko, J.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foster, J.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Gobbi, B.; Grim, G.P.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Koeth, T.; Krammer, M.; Lander, R.; Logiudice, A.; Lu, R.; Lynne, L.M.; Manfredotti, C.; Meier, D.; Mishina, M.; Moroni, L.; Oh, A.; Pan, L.S.; Pernicka, M.; Perera, L. E-mail: perera@physics.rutgers.edu; Pirollo, S.; Plano, R.; Procario, M.; Riester, J.L.; Roe, S.; Rott, C.; Rousseau, L.; Rudge, A.; Russ, J.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trischuk, W.; Tromson, D.; Vittone, E.; Wedenig, R.; Weilhammer, P.; White, C.; Zeuner, W.; Zoeller, M

2001-06-01

Diamond based pixel detectors are a promising radiation-hard technology for use at the LHC. We present first results on a CMS diamond pixel sensor. With a threshold setting of 2000 electrons, an average pixel efficiency of 78% was obtained for normally incident minimum ionizing particles.

Multi-control modes for a master-slave manipulator with different configurations and its maneuverability

International Nuclear Information System (INIS)

Matsuhira, Nobuto; Asakura, Makoto; Bamba, Hiroyuki

1995-01-01

The new master-slave control method is proposed on multi-control modes for a master-slave manipulator with different configurations. A virtual internal model following control is applied to position symmetrical bilateral control. In our method, a master-slave control mode (MS-mode), a joystick control mode (JS-mode), a master arm offset mode (OM-mode), and a servo hold mode (LK-mode) are able to be realized by operating the desired output values of the virtual internal models in a common control algorithm. There is compliant characteristic between the master and slave models. In the result of evaluation experiments between the MS-mode and the JS-mode, although the MS-mode is superior to the JS-mode in manipulating a fine task, our JS-mode is found to be useful to carry out such a task compared with a conventional JS-mode which only directs the rates for the slave arm. In the JS-mode, the slave arm moves to the position where the reaction force of the slave arm and the operating force of the master arm are balanced. Thus, it is possible either to control an overload for an object and to control the contact force. The validity of the proposed method is verified. (author)

How spectroscopic x-ray imaging benefits from inter-pixel communication

CERN Document Server

Koenig, Thomas; Hamann, Elias; Cecilia, Angelica; Ballabriga, Rafael; Campbell, Michael; Ruat, Marie; Tlustos, Lukas; Fauler, Alex; Fiederle, Michael; Baumbach, Tilo

2014-01-01

Spectroscopic x-ray imaging based on pixellated semiconductor detectors can be sensitive to charge sharing and K-fluorescence, depending on the sensor material used, its thickness and the pixel pitch employed. As a consequence, spectroscopic resolution is partially lost. In this paper, we study a new detector ASIC, the Medipix3RX, that offers a novel feature called charge summing, which is established by making adjacent pixels communicate with each other. Consequently, single photon interactions resulting in multiple hits are almost completely avoided. We investigate this charge summing mode with respect to those of its imaging properties that are of interest in medical physics and benchmark them against the case without charge summing. In particular, we review its influence on spectroscopic resolution and find that the low energy bias normally present when recording energy spectra is dramatically reduced. Furthermore, we show that charge summing provides a modulation transfer function which is almost indepen...

Progress on the design of a data push architecture for an array of optimized time tagging pixels

International Nuclear Information System (INIS)

Shapiro, S.; Cords, D.; Mani, S.; Holbrook, B.; Atlas, E.

1993-06-01

A pixel array has been proposed which features a completely data driven architecture. A pixel cell has been designed that has been optimized for this readout. It retains the features of preceding designs which allow low noise operation, time stamping, analog signal processing, XY address recording, ghost elimination and sparse data transmission. The pixel design eliminates a number of problems inherent in previous designs, by the use of sampled data techniques, destructive readout, and current mode output drivers. This architecture and pixel design is directed at applications such as a forward spectrometer at the SSC, an e + e - B factory at SLAC, and fixed target experiments at FNAL

Experimental demonstration of a broadband two-mode multi/demultiplexer based on asymmetric Y-junctions

Science.gov (United States)

Li, Haiqin; Wang, Pengjun; Yang, Tianjun; Dai, Tingge; Wang, Gencheng; Li, Shiqi; Chen, Weiwei; Yang, Jianyi

2018-03-01

A broadband two-mode multi/demultiplexer using asymmetric Y-junctions is designed and experimentally demonstrated on a silicon-on-insulator platform for on-chip mode-division multiplexing applications. Within a bandwidth from 1513 to 1619 nm, the fabricated device, which consists of a two-mode multiplexer, a multimode straight waveguide, and a two-mode demultiplexer, exhibits demultiplexing crosstalk of less than -9.1 dB. The demultiplexing crosstalk as low as -42.1 dB, lower than -12.8 dB over the C band can be obtained. The measured insertion loss varies from 0.40 to 0.56 dB at a wavelength of 1550 nm. A transmission experiment of 10 Gbit/s electrical signals carried on TE0 and TE1 modes is successfully achieved with open and clear eye diagrams.

Implementation and flight-test of a multi-mode rotorcraft flight-control system for single-pilot use in poor visibility

Science.gov (United States)

Hindson, William S.

1987-01-01

A flight investigation was conducted to evaluate a multi-mode flight control system designed according to the most recent recommendations for handling qualities criteria for new military helicopters. The modes and capabilities that were included in the system are those considered necessary to permit divided-attention (single-pilot) lowspeed and hover operations near the ground in poor visibility conditions. Design features included mode-selection and mode-blending logic, the use of an automatic position-hold mode that employed precision measurements of aircraft position, and a hover display which permitted manually-controlled hover flight tasks in simulated instrument conditions. Pilot evaluations of the system were conducted using a multi-segment evaluation task. Pilot comments concerning the use of the system are provided, and flight-test data are presented to show system performance.

Role of interbranch pumping on the quantum-statistical behavior of multi-mode magnons in ferromagnetic nanowires

Science.gov (United States)

Haghshenasfard, Zahra; Cottam, M. G.

2018-01-01

Theoretical studies are reported for the quantum-statistical properties of microwave-driven multi-mode magnon systems as represented by ferromagnetic nanowires with a stripe geometry. Effects of both the exchange and the dipole-dipole interactions, as well as a Zeeman term for an external applied field, are included in the magnetic Hamiltonian. The model also contains the time-dependent nonlinear effects due to parallel pumping with an electromagnetic field. Using a coherent magnon state representation in terms of creation and annihilation operators, we investigate the effects of parallel pumping on the temporal evolution of various nonclassical properties of the system. A focus is on the interbranch mixing produced by the pumping field when there are three or more modes. In particular, the occupation magnon number and the multi-mode cross correlations between magnon modes are studied. Manipulation of the collapse and revival phenomena of the average magnon occupation number and the control of the cross correlation between the magnon modes are demonstrated through tuning of the parallel pumping field amplitude and appropriate choices for the coherent magnon states. The cross correlations are a direct consequence of the interbranch pumping effects and do not appear in the corresponding one- or two-mode magnon systems.

Pixel Experiments

DEFF Research Database (Denmark)

Petersen, Kjell Yngve; Søndergaard, Karin; Augustesen, Christina

2015-01-01

Pixel Experiments The term pixel is traditionally defined as any of the minute elements that together constitute a larger context or image. A pixel has its own form and is the smallest unit seen within a larger structure. In working with the potentials of LED technology in architectural lighting...... for using LED lighting in lighting design practice. The speculative experiments that have been set-up have aimed to clarify the variables that can be used as parameters in the design of lighting applications; including, for example, the structuring and software control of light. The experiments also...... elucidate and exemplify already well-known problems in relation to the experience of vertical and horizontal lighting. Pixel Experiments exist as a synergy between speculative test setups and lighting design in practice. This book is one of four books that is published in connection with the research...

Probing Defects in a Small Pixellated CdTe Sensor Using an Inclined Mono Energetic X-Ray Micro Beam

Science.gov (United States)

Fröjdh, Erik; Fröjdh, C.; Gimenez, E. N.; Krapohl, D.; Maneuski, D.; Norlin, B.; O'Shea, V.; Wilhelm, H.; Tartoni, N.; Thungström, G.; Zain, R. M.

2013-08-01

High quantum efficiency is important in X-ray imaging applications. This means using high-Z sensor materials. Unfortunately many of these materials suffer from defects that cause non-ideal charge transport. In order to increase the understanding of these defects, we have mapped the 3D response of a number of defects in two 1 mm thick CdTe sensors with different pixel sizes (55 μm and 110 μm) using a monoenergetic microbeam at 79 keV. The sensors were bump bonded to Timepix read out chips. Data was collected in photon counting as well as time-over-threshold mode. The time-over-threshold mode is a very powerful tool to investigate charge transport properties and fluorescence in pixellated detectors since the signal from the charge that each photon deposits in each pixel can be analyzed. Results show distorted electrical field around the defects, indications of excess leakage current and large differences in behavior between electron collection and hole collection mode. The experiments were carried out on the Extreme Conditions Beamline I15 at Diamond Light Source.

Multi-scale-nonlinear interactions among macro-MHD mode, micro-turbulence, and zonal flow

International Nuclear Information System (INIS)

Ishizawa, Akihiro; Nakajima, Noriyoshi

2007-01-01

This is the first numerical simulation demonstrating that macro-magnetohydrodynamic (macro-MHD) mode is exited as a result of multi-scale interaction in a quasi-steady equilibrium formed by a balance between zonal flow and micro-turbulence via reduced-two-fluid simulation. Only after obtaining the equilibrium which includes zonal flow and the turbulence caused by kinetic ballooning mode is this simulation of macro-MHD mode, double tearing mode, accomplished. In the quasi-steady equilibrium a macro-fluctuation which has the same helicity as that of double tearing mode is a part of the turbulence until it grows as a macro-MHD mode finally. When the macro-MHD grows it effectively utilize free energy of equilibrium current density gradient because of positive feedback loop between suppression of zonal flow and growth of the macro-fluctuation causing magnetic reconnection. Thus once the macro-MHD grows from the quasi-equilibrium, it does not go back. This simulation is more comparable with experimental observation of growing macro-fluctuation than traditional MHD simulation of linear instabilities in a static equilibrium. (author)

Demonstration of the CDMA-mode CAOS smart camera.

Science.gov (United States)

Riza, Nabeel A; Mazhar, Mohsin A

2017-12-11

Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera. Using four different bright light test target scenes, successfully demonstrated is a proof-of-concept visible band CAOS smart camera operating in the CDMA-mode using up-to 4096 bits length Walsh design CAOS pixel codes with a maximum 10 KHz code bit rate giving a 0.4096 seconds CAOS frame acquisition time. A 16-bit analog-to-digital converter (ADC) with time domain correlation digital signal processing (DSP) generates the CDMA-mode images with a 3600 CAOS pixel count and a best spatial resolution of one micro-mirror square pixel size of 13.68 μm side. The CDMA-mode of the CAOS smart camera is suited for applications where robust high dynamic range (DR) imaging is needed for un-attenuated un-spoiled bright light spectrally diverse targets.

OM4 bend insensitive multi-mode fibers’ usefulness for MCM integration

International Nuclear Information System (INIS)

Guzowski, Bartłomiej; Lisik, Zbigniew; Tosik, Grzegorz; Ciupa, Emilia

2012-01-01

Highlights: ► The influence of high temperature exposure on OM4 fibers’ mechanical properties. ► Researching OM4 class fibers for use in innovative Optical Multi Chip Module. ► The influence of bending at a very small radius, up to 2 mm, on MM fibers. - Abstract: For future generations of electronic systems, a severe bottleneck is expected on the interconnection level and the use of optical interconnection is considered as one of the most promising solutions in this matter. Recent progress in fiber development resulted in new generation of optical fibers that are bend insensitive. This makes them ideal for Multi Chip Module (MCM) application. This paper focuses on OM4 bend insensitive multi-mode fibers’ usefulness for MCM integration, particularly the investigation of MM fiber loss is presented, which is influenced by bend diameter and the fiber's mechanical performance under influence of high temperature (400 °C–1000 °C adequate to MCM production process).

PIXEL 2010 - A Resume

International Nuclear Information System (INIS)

Wermes, N.

2011-01-01

The Pixel 2010 conference focused on semiconductor pixel detectors for particle tracking/vertexing as well as for imaging, in particular for synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have impressively started showing their capabilities. X-ray imaging detectors, also using the hybrid pixel technology, have greatly advanced the experimental possibilities for diffraction experiments. Monolithic or semi-monolithic devices like CMOS active pixels and DEPFET pixels have now reached a state such that complete vertex detectors for RHIC and superKEKB are being built with these technologies. Finally, new advances towards fully monolithic active pixel detectors, featuring full CMOS electronics merged with efficient signal charge collection, exploiting standard CMOS technologies, SOI and/or 3D integration, show the path for the future. This resume attempts to extract the main statements of the results and developments presented at this conference.

A 3D multi-mode geometry-independent RMP optimization method and its application to TCV

International Nuclear Information System (INIS)

Rossel, J X; Moret, J-M; Martin, Y

2010-01-01

Resonant magnetic perturbation (RMP) and error field correction (EFC) produced by toroidally and poloidally distributed coil systems can be optimized if each coil is powered with an independent power supply. A 3D multi-mode geometry-independent Lagrange method has been developed and appears to be an efficient way to minimize the parasitic spatial modes of the magnetic perturbation and the coil current requirements while imposing the amplitude and phase of a number of target modes. A figure of merit measuring the quality of a perturbation spectrum with respect to RMP independently of the considered coil system or plasma equilibrium is proposed. To ease the application of the Lagrange method, a spectral characterization of the system, based on a generalized discrete Fourier transform applied in current space, is performed to determine how spectral degeneracy and side-band creation limit the set of simultaneously controllable target modes. This characterization is also useful to quantify the efficiency of the coil system in each toroidal mode number and to know whether optimization is possible for a given number of target modes. The efficiency of the method is demonstrated in the special case of a multi-purpose saddle coil system proposed as part of a future upgrade of Tokamak a Configuration Variable (TCV). This system consists of three rows of eight internal coils, each coil having independent power supplies, and provides simultaneously EFC, RMP and fast vertical position control.

Pixel-Cluster Counting Luminosity Measurement in ATLAS

CERN Document Server

McCormack, William Patrick; The ATLAS collaboration

2016-01-01

A precision measurement of the delivered luminosity is a key component of the ATLAS physics program at the Large Hadron Collider (LHC). A fundamental ingredient of the strategy to control the systematic uncertainties affecting the absolute luminosity has been to compare the measurements of several luminometers, most of which use more than one counting technique. The level of consistency across the various methods provides valuable cross-checks as well as an estimate of the detector-related systematic uncertainties. This poster describes the development of a luminosity algorithm based on pixel-cluster counting in the recently installed ATLAS inner b-layer (IBL), using data recorded during the 2015 pp run at the LHC. The noise and background contamination of the luminosity-associated cluster count is minimized by a multi-component fit to the measured cluster-size distribution in the forward pixel modules of the IBL. The linearity, long-term stability and statistical precision of the cluster-counting method are ...

Pixel-Cluster Counting Luminosity Measurement In ATLAS

CERN Document Server

AUTHOR|(SzGeCERN)782710; The ATLAS collaboration

2017-01-01

A precision measurement of the delivered luminosity is a key component of the ATLAS physics program at the Large Hadron Collider (LHC). A fundamental ingredient of the strategy to control the systematic uncertainties affecting the absolute luminosity has been to compare the measure- ments of several luminometers, most of which use more than one counting technique. The level of consistency across the various methods provides valuable cross-checks as well as an estimate of the detector-related systematic uncertainties. This poster describes the development of a luminosity algorithm based on pixel-cluster counting in the recently installed ATLAS inner b-layer (IBL), using data recorded during the 2015 pp run at the LHC. The noise and background contamination of the luminosity-associated cluster count is minimized by a multi-component fit to the measured cluster-size distribution in the forward pixel modules of the IBL. The linearity, long-term stability and statistical precision of the cluster- counting method a...

Plantar fascia softening in plantar fasciitis with normal B-mode sonography.

Science.gov (United States)

Wu, Chueh-Hung; Chen, Wen-Shiang; Wang, Tyng-Guey

2015-11-01

To investigate plantar fascia elasticity in patients with typical clinical manifestations of plantar fasciitis but normal plantar fascia morphology on B-mode sonography. Twenty patients with plantar fasciitis (10 unilateral and 10 bilateral) and 30 healthy volunteers, all with normal plantar fascia morphology on B-mode sonography, were included in the study. Plantar fascia elasticity was evaluated by sonoelastographic examination. All sonoelastograms were quantitatively analyzed, and less red pixel intensity was representative of softer tissue. Pixel intensity was compared among unilateral plantar fasciitis patients, bilateral plantar fasciitis patients, and healthy volunteers by one-way ANOVA. A post hoc Scheffé's test was used to identify where the differences occurred. Compared to healthy participants (red pixel intensity: 146.9 ± 9.1), there was significantly less red pixel intensity in the asymptomatic sides of unilateral plantar fasciitis (140.4 ± 7.3, p = 0.01), symptomatic sides of unilateral plantar fasciitis (127.1 ± 7.4, p plantar fasciitis (129.4 ± 7.5, p plantar fascia thickness or green or blue pixel intensity among these groups. Sonoelastography revealed that the plantar fascia is softer in patients with typical clinical manifestations of plantar fasciitis, even if they exhibit no abnormalities on B-mode sonography.

Active pixel sensor array with electronic shuttering

Science.gov (United States)

Fossum, Eric R. (Inventor)

2002-01-01

An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

High-speed X-ray imaging pixel array detector for synchrotron bunch isolation.

Science.gov (United States)

Philipp, Hugh T; Tate, Mark W; Purohit, Prafull; Shanks, Katherine S; Weiss, Joel T; Gruner, Sol M

2016-03-01

A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8-12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10-100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed.

Geiger-Nuttall Law for Nuclei in Strong Electromagnetic Fields

Science.gov (United States)

Delion, D. S.; Ghinescu, S. A.

2017-11-01

We investigate the influence of a strong laser electromagnetic field on the α -decay rate by using the Hennenberger frame of reference. We introduce an adimensional parameter D =S0/R0, where R0 is the geometrical nuclear radius and S0˜√{I }/ω2 is a length parameter depending on the laser intensity I and frequency ω . We show that the barrier penetrability has a strong increase for intensities corresponding to D >Dcrit=1 , due to the fact that the resulting Coulomb potential becomes strongly anisotropic even for spherical nuclei. As a consequence, the contribution of the monopole term increases the barrier penetrability by 2 orders of magnitude, while the total contribution has an effect of 6 orders of magnitude at D ˜3 Dcrit. In the case of deformed nuclei, the electromagnetic field increases the penetrability by an additional order of magnitude for a quadrupole deformation β2˜0.3 . The influence of the electromagnetic field can be expressed in terms of a shifted Geiger-Nuttal law by a term depending on S0 and deformation.

Semiconductor micropattern pixel detectors: a review of the beginnings

International Nuclear Information System (INIS)

Heijne, E.H.M.

2001-01-01

The innovation in monolithic and hybrid semiconductor 'micropattern' or 'reactive' pixel detectors for tracking in particle physics was actually to fit logic and pulse processing electronics with μW power on a pixel area of less than 0.04 mm 2 , retaining the characteristics of a traditional nuclear amplifier chain. The ns timing precision in conjunction with local memory and logic operations allowed event selection at >10 MHz rates with unambiguous track reconstruction even at particle multiplicities >10 cm -2 . The noise in a channel was ∼100e - rms and enabled binary operation with random noise 'hits' at a level -8 . Rectangular pixels from 75 μmx500 μm down to 34 μmx125 μm have been used by different teams. In binary mode a tracking precision from 6 to 14 μm was obtained, and using analog interpolation one came close to 1 μm. Earlier work, still based on charge integrating imaging circuits, provided a starting point. Two systems each with more than 1 million sensor + readout channels have been built, for WA97-NA57 and for the Delphi very forward tracker. The use of 0.5 μm and 0.25 μm CMOS and enclosed geometry for the transistors in the pixel readout chips resulted in radiation hardness of ∼2 Mrad, respectively, >30 Mrad

Weighted Local Active Pixel Pattern (WLAPP for Face Recognition in Parallel Computation Environment

Directory of Open Access Journals (Sweden)

Gundavarapu Mallikarjuna Rao

2013-10-01

Full Text Available Abstract  - The availability of multi-core technology resulted totally new computational era. Researchers are keen to explore available potential in state of art-machines for breaking the bearer imposed by serial computation. Face Recognition is one of the challenging applications on so ever computational environment. The main difficulty of traditional Face Recognition algorithms is lack of the scalability. In this paper Weighted Local Active Pixel Pattern (WLAPP, a new scalable Face Recognition Algorithm suitable for parallel environment is proposed.  Local Active Pixel Pattern (LAPP is found to be simple and computational inexpensive compare to Local Binary Patterns (LBP. WLAPP is developed based on concept of LAPP. The experimentation is performed on FG-Net Aging Database with deliberately introduced 20% distortion and the results are encouraging. Keywords — Active pixels, Face Recognition, Local Binary Pattern (LBP, Local Active Pixel Pattern (LAPP, Pattern computing, parallel workers, template, weight computation.  

Multi-level single mode 2D polymer waveguide optical interconnects using nano-imprint lithography

NARCIS (Netherlands)

Khan, M.U.; Justice, J.; Petäjä, J.; Korhonen, T.; Boersma, A.; Wiegersma, S.; Karppinen, M.; Corbett, B.

2015-01-01

Single and multi-layer passive optical interconnects using single mode polymer waveguides are demonstrated using UV nano-imprint lithography. The fabrication tolerances associated with imprint lithography are investigated and we show a way to experimentally quantify a small variation in index

Development of a counting pixel detector for 'Digitales Roentgen'

International Nuclear Information System (INIS)

Lindner, M.

2001-08-01

The development of a single photon counting X-ray imaging detector for medical applications using hybrid pixel detectors is reported. The electronics development from the first prototype derived from detector development for particle physics experiments (ATLAS) to the imaging chip MPEC (multi picture element counters) for medical applications is described. This chip consists of 32 x 32 pixels of 200 μm x 200 μm size, each containing the complete read out electronics, i.e. an amplifier, two discriminators with adjustable thresholds and two 18-bit linear feedback shift-counters allowing energy windowing for contrast increase. Results on electronics performance are shown as well as measurements with several semiconductor materials (Si, GaAs, CdTe). Important aspects like detection efficiency, sensor homogeneity, linearity and spatial resolution are discussed. (orig.)

Methods on TLD management be applicable in nuclear power plantsunder the multi-reactor operational mode

International Nuclear Information System (INIS)

Luo Huiyong; Wen Qinghua; Li Ruirong; Yu Enjian

2006-01-01

This paper discusses the methods on management of TLD dosimeters adopted in DNMC and other NPPs, analyzes and evaluates their both defects and advantages. Facing the coming of the multi-reactor operational mode applied in NPPs, a new method intelligent management mode is put forward, this optimized method not only assures the accuracy of TLD's measurement but also reduces the cost of production and improves the efficiency of management greatly. (authors)

Hot pixel generation in active pixel sensors: dosimetric and micro-dosimetric response

Science.gov (United States)

Scheick, Leif; Novak, Frank

2003-01-01

The dosimetric response of an active pixel sensor is analyzed. heavy ions are seen to damage the pixel in much the same way as gamma radiation. The probability of a hot pixel is seen to exhibit behavior that is not typical with other microdose effects.

PEP-4 geiger-mode hexagonal calorimeter

International Nuclear Information System (INIS)

Wenzel, W.A.

1982-01-01

The design and performance of the calorimeter are briefly described. Design aspects include illustrations of the active volume of the detector, edge connections, module assembly and analog electronics. Performance data for cosmic rays and radiation sources, including efficiency and channel sensitivity are discussed

System test and noise performance studies at the ATLAS pixel detector

International Nuclear Information System (INIS)

Weingarten, J.

2007-09-01

The central component of the ATLAS Inner Tracker is the pixel detector. It consists of three barrel layers and three disk-layers in the end-caps in both forward directions. The innermost barrel layer is mounted at a distance of about 5 cm from the interaction region. With its very high granularity, truly two-dimensional hit information, and fast readout it is well suited to cope with the high densities of charged tracks, expected this close to the interaction region. The huge number of readout channels necessitates a very complex services infrastructure for powering, readout and safety. After a description of the pixel detector and its services infrastructure, key results from the system test at CERN are presented. Furthermore the noise performance of the pixel detector, crucial for high tracking and vertexing efficiencies, is studied. Measurements of the single-channel random noise are presented together with studies of common mode noise and measurements of the noise occupancy using a random trigger generator. (orig.)

System test and noise performance studies at the ATLAS pixel detector

Energy Technology Data Exchange (ETDEWEB)

Weingarten, J.

2007-09-15

The central component of the ATLAS Inner Tracker is the pixel detector. It consists of three barrel layers and three disk-layers in the end-caps in both forward directions. The innermost barrel layer is mounted at a distance of about 5 cm from the interaction region. With its very high granularity, truly two-dimensional hit information, and fast readout it is well suited to cope with the high densities of charged tracks, expected this close to the interaction region. The huge number of readout channels necessitates a very complex services infrastructure for powering, readout and safety. After a description of the pixel detector and its services infrastructure, key results from the system test at CERN are presented. Furthermore the noise performance of the pixel detector, crucial for high tracking and vertexing efficiencies, is studied. Measurements of the single-channel random noise are presented together with studies of common mode noise and measurements of the noise occupancy using a random trigger generator. (orig.)

Signal height in silicon pixel detectors irradiated with pions and protons

International Nuclear Information System (INIS)

Rohe, T.; Acosta, J.; Bean, A.; Dambach, S.; Erdmann, W.; Langenegger, U.; Martin, C.; Meier, B.; Radicci, V.; Sibille, J.; Trueb, P.

2010-01-01

Pixel detectors are used in the innermost part of multi-purpose experiments at the Large Hadron Collider (LHC) and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of the detectors has been tested thoroughly up to the fluences expected at the LHC. In case of an LHC upgrade the fluence will be much higher and it is not yet clear up to which radii the present pixel technology can be used. To establish such a limit, pixel sensors of the size of one CMS pixel readout chip (PSI46V2.1) have been bump bonded and irradiated with positive pions up to 6x10 14 n eq /cm 2 at PSI and with protons up to 5x10 15 n eq /cm 2 . The sensors were taken from production wafers of the CMS barrel pixel detector. They use n-type DOFZ material with a resistance of about 3.7kΩcm and an n-side read out. As the performance of silicon sensors is limited by trapping, the response to a Sr-90 source was investigated. The highly energetic beta-particles represent a good approximation to minimum ionising particles. The bias dependence of the signal for a wide range of fluences will be presented.

A Multi-Modality CMOS Sensor Array for Cell-Based Assay and Drug Screening.

Science.gov (United States)

Chi, Taiyun; Park, Jong Seok; Butts, Jessica C; Hookway, Tracy A; Su, Amy; Zhu, Chengjie; Styczynski, Mark P; McDevitt, Todd C; Wang, Hua

2015-12-01

In this paper, we present a fully integrated multi-modality CMOS cellular sensor array with four sensing modalities to characterize different cell physiological responses, including extracellular voltage recording, cellular impedance mapping, optical detection with shadow imaging and bioluminescence sensing, and thermal monitoring. The sensor array consists of nine parallel pixel groups and nine corresponding signal conditioning blocks. Each pixel group comprises one temperature sensor and 16 tri-modality sensor pixels, while each tri-modality sensor pixel can be independently configured for extracellular voltage recording, cellular impedance measurement (voltage excitation/current sensing), and optical detection. This sensor array supports multi-modality cellular sensing at the pixel level, which enables holistic cell characterization and joint-modality physiological monitoring on the same cellular sample with a pixel resolution of 80 μm × 100 μm. Comprehensive biological experiments with different living cell samples demonstrate the functionality and benefit of the proposed multi-modality sensing in cell-based assay and drug screening.

Separation of metadata and pixel data to speed DICOM tag morphing.

Science.gov (United States)

Ismail, Mahmoud; Philbin, James

2013-01-01

The DICOM information model combines pixel data and metadata in single DICOM object. It is not possible to access the metadata separately from the pixel data. There are use cases where only metadata is accessed. The current DICOM object format increases the running time of those use cases. Tag morphing is one of those use cases. Tag morphing includes deletion, insertion or manipulation of one or more of the metadata attributes. It is typically used for order reconciliation on study acquisition or to localize the issuer of patient ID (IPID) and the patient ID attributes when data from one domain is transferred to a different domain. In this work, we propose using Multi-Series DICOM (MSD) objects, which separate metadata from pixel data and remove duplicate attributes, to reduce the time required for Tag Morphing. The time required to update a set of study attributes in each format is compared. The results show that the MSD format significantly reduces the time required for tag morphing.

Adhesive performance of a multi-mode adhesive system: 1-year in vitro study.

Science.gov (United States)

Marchesi, Giulio; Frassetto, Andrea; Mazzoni, Annalisa; Apolonio, Fabianni; Diolosà, Marina; Cadenaro, Milena; Di Lenarda, Roberto; Pashley, David H; Tay, Franklin; Breschi, Lorenzo

2014-05-01

The aim of this study was to investigate the adhesive stability over time of a multi-mode one-step adhesive applied using different bonding techniques on human coronal dentine. The hypotheses tested were that microtensile bond strength (μTBS), interfacial nanoleakage expression and matrix metalloproteinases (MMPs) activation are not affected by the adhesive application mode (following the use of self-etch technique or with the etch-and-rinse technique on dry or wet dentine) or by ageing for 24h, 6 months and 1year in artificial saliva. Human molars were cut to expose middle/deep dentine and assigned to one of the following bonding systems (N=15): (1) Scotchbond Universal (3M ESPE) self-etch mode, (2) Scotchbond Universal etch-and-rinse technique on wet dentine, (3) Scotchbond Universal etch-and-rinse technique on dry dentine, and (4) Prime&Bond NT (Dentsply De Trey) etch-and-rinse technique on wet dentine (control). Specimens were processed for μTBS test in accordance with the non-trimming technique and stressed to failure after 24h, 6 months or 1 year. Additional specimens were processed and examined to assay interfacial nanoleakage and MMP expression. At baseline, no differences between groups were found. After 1 year of storage, Scotchbond Universal applied in the self-etch mode and Prime&Bond NT showed higher μTBS compared to the other groups. The lowest nanoleakage expression was found for Scotchbond Universal applied in the self-etch mode, both at baseline and after storage. MMPs activation was found after application of each tested adhesive. The results of this study support the use of the self-etch approach for bonding the tested multi-mode adhesive system to dentine due to improved stability over time. Improved bonding effectiveness of the tested universal adhesive system on dentine may be obtained if the adhesive is applied with the self-etch approach. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dual-mode nested search method for categorical uncertain multi-objective optimization

Science.gov (United States)

Tang, Long; Wang, Hu

2016-10-01

Categorical multi-objective optimization is an important issue involved in many matching design problems. Non-numerical variables and their uncertainty are the major challenges of such optimizations. Therefore, this article proposes a dual-mode nested search (DMNS) method. In the outer layer, kriging metamodels are established using standard regular simplex mapping (SRSM) from categorical candidates to numerical values. Assisted by the metamodels, a k-cluster-based intelligent sampling strategy is developed to search Pareto frontier points. The inner layer uses an interval number method to model the uncertainty of categorical candidates. To improve the efficiency, a multi-feature convergent optimization via most-promising-area stochastic search (MFCOMPASS) is proposed to determine the bounds of objectives. Finally, typical numerical examples are employed to demonstrate the effectiveness of the proposed DMNS method.

From hybrid to CMOS pixels ... a possibility for LHC's pixel future?

International Nuclear Information System (INIS)

Wermes, N.

2015-01-01

Hybrid pixel detectors have been invented for the LHC to make tracking and vertexing possible at all in LHC's radiation intense environment. The LHC pixel detectors have meanwhile very successfully fulfilled their promises and R and D for the planned HL-LHC upgrade is in full swing, targeting even higher ionising doses and non-ionising fluences. In terms of rate and radiation tolerance hybrid pixels are unrivaled. But they have disadvantages as well, most notably material thickness, production complexity, and cost. Meanwhile also active pixel sensors (DEPFET, MAPS) have become real pixel detectors but they would by far not stand the rates and radiation faced from HL-LHC. New MAPS developments, so-called DMAPS (depleted MAPS) which are full CMOS-pixel structures with charge collection in a depleted region have come in the R and D focus for pixels at high rate/radiation levels. This goal can perhaps be realised exploiting HV technologies, high ohmic substrates and/or SOI based technologies. The paper covers the main ideas and some encouraging results from prototyping R and D, not hiding the difficulties

12 GeV detector technology at Jefferson Lab

Energy Technology Data Exchange (ETDEWEB)

Leckey, John P. [Indiana University, Bloomington, IN 47405 (United States); Collaboration: GlueX Collaboration

2013-04-19

The Thomas Jefferson National Accelerator Facility (JLab) is presently in the middle of an upgrade to increase the energy of its CW electron beam from 6 GeV to 12 GeV along with the addition of a fourth experimental hall. Driven both by necessity and availability, novel detectors and electronics modules have been used in the upgrade. One such sensor is the Silicon Photomultiplier (SiPM), specifically a Multi-Pixel Photon Counter (MPPC), which is an array of avalanche photodiode pixels operating in Geiger mode that are used to sense photons. The SiPMs replace conventional photomultiplier tubes and have several distinct advantages including the safe operation in a magnetic field and the lack of need for high voltage. Another key to 12 GeV success is advanced fast electronics. Jlab will use custom 250 MHz and 125 MHz 12-bit analog to digital converters (ADCs) and time to digital converters (TDCs) all of which take advantage of VME Switched Serial (VXS) bus with its GB/s high bandwidth readout capability. These new technologies will be used to readout drift chambers, calorimeters, spectrometers and other particle detectors at Jlab once the 12 GeV upgrade is complete. The largest experiment at Jlab utilizing these components is GlueX - an experiment in the newly constructed Hall D that will study the photoproduction of light mesons in the search for hybrid mesons. The performance of these components and their respective detectors will be presented.

High-speed imaging at high x-ray energy: CdTe sensors coupled to charge-integrating pixel array detectors

Energy Technology Data Exchange (ETDEWEB)

Becker, Julian; Tate, Mark W.; Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Purohit, Prafull [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Chamberlain, Darol [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

2016-07-27

Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we describe the hybridization of CdTe sensors to two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods <150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128×128 pixel array with (150 µm){sup 2} pixels.

Pixel detector bias supply and control using embedded multicore processors

CERN Document Server

AUTHOR|(CDS)2099144; Akram Alomainy

The aim of the project is to create a software controlled, open source, low footprint and low power high voltage bias supply and current monitor for a pixelated radiation sensor. The solution is based on the LT3905 integrated circuit and the multi-core XMOS xCore 200 microcontroller and it is intended to be used in a battery powered, mobile platform for educational settings.

Rayleigh waves ellipticity and mode mis-identification in multi-channel analysis of surface waves

DEFF Research Database (Denmark)

Boaga, Jacopo; Cassiani, Giorgio; Strobbia, Claudio

dispersion curve which is then inverted. Typically, single component vertical and multi channel receivers are used. In most cases the inversion of the dispersion properties is carried out assuming that the experimental dispersion curve corresponds to a single mode, mostly the fundamental Rayleigh mode...... to each other reaching similar Rayleigh velocity. It is known ‘osculation’ happens generally in presence of strong velocity contrasts, typically with a fast bedrock underlying loose sediments. The practical limitations of the acquired data affect the spectral and modal resolution, making it often...

Radiation hardness of CMS pixel barrel modules

International Nuclear Information System (INIS)

Rohe, T.; Bean, A.; Erdmann, W.; Kaestli, H.-C.; Khalatyan, S.; Meier, B.; Radicci, V.; Sibille, J.

2010-01-01

Pixel detectors are used in the innermost part of the multi purpose experiments at the LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has been thoroughly tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6x10 14 n eq /cm 2 and with 21 GeV protons at CERN up to 5x10 15 n eq /cm 2 . After irradiation the response of the system to beta particles from a 90 Sr source was measured to characterise the charge collection efficiency of the sensor. Radiation induced changes in the readout chip were also measured. The results show that the present pixel modules can be expected to be still operational after a fluence of 2.8x10 15 n eq /cm 2 . Samples irradiated up to 5x10 15 n eq /cm 2 still see the beta particles. However, further tests are needed to confirm whether a stable operation with high particle detection efficiency is possible after such a high fluence.

Synthesis of Fe–Ni bimetallic nanoparticles from pixel target ablation: plume dynamics and surface characterization

International Nuclear Information System (INIS)

Niu Xiaoxu; Murray, Paul T.; Sarangan, Andrew

2012-01-01

A novel Fe–Ni bimetallic nanoparticle synthesis technique, denoted pixel target ablation, is reported. The technique entails ablating a thin film target consisting of patterned Fe and Ni pixels with a selected ratio using a KrF excimer laser. The laser energy breaks a known amount of target materials into metal atoms, which then form nanoparticles by recombination in the gas phase. Due to the nature of thin-film ablation, splashing of large particles was eliminated with the added benefit of minimizing nanoparticle agglomeration. Plume dynamics and surface characterizations were carried out to exploit the formation of Fe–Ni nanoparticles more fully. The composition was readily controlled by varying the initial relative amount of Fe and Ni target pixels. Synthesis of multi-element nanoparticles by pixel target ablation should be possible with any element combination that can be prepared as a thin-film target.

FACT light collection - solid light concentrators in Cherenkov Astronomy

Energy Technology Data Exchange (ETDEWEB)

Braun, Isabel [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Collaboration: FACT-Collaboration

2011-07-01

Pixelized cameras of Imaging Atmospheric Cherenkov Telescopes use hollow light guides with reflective surfaces based on the Winston cone design. These cones minimize insensitive spaces between the photo sensors and shield the camera from stray background light by limiting the angular acceptance to the primary reflector area. FACT (First G-APD Cherenkov Telescope) will be the first IACT with Geiger-mode avalanche photodiodes as light sensors. Solid light concentrators complementing these sensors will be used instead of hollow Winston cones. We will present simulations and measurements of our light collector design, which was optimized for the requirements of the FACT telescope and detector, and discuss the specific differences to more traditional solutions.

A digital pixel cell for address event representation image convolution processing

Science.gov (United States)

Camunas-Mesa, Luis; Acosta-Jimenez, Antonio; Serrano-Gotarredona, Teresa; Linares-Barranco, Bernabe

2005-06-01

Address Event Representation (AER) is an emergent neuromorphic interchip communication protocol that allows for real-time virtual massive connectivity between huge number of neurons located on different chips. By exploiting high speed digital communication circuits (with nano-seconds timings), synaptic neural connections can be time multiplexed, while neural activity signals (with mili-seconds timings) are sampled at low frequencies. Also, neurons generate events according to their information levels. Neurons with more information (activity, derivative of activities, contrast, motion, edges,...) generate more events per unit time, and access the interchip communication channel more frequently, while neurons with low activity consume less communication bandwidth. AER technology has been used and reported for the implementation of various type of image sensors or retinae: luminance with local agc, contrast retinae, motion retinae,... Also, there has been a proposal for realizing programmable kernel image convolution chips. Such convolution chips would contain an array of pixels that perform weighted addition of events. Once a pixel has added sufficient event contributions to reach a fixed threshold, the pixel fires an event, which is then routed out of the chip for further processing. Such convolution chips have been proposed to be implemented using pulsed current mode mixed analog and digital circuit techniques. In this paper we present a fully digital pixel implementation to perform the weighted additions and fire the events. This way, for a given technology, there is a fully digital implementation reference against which compare the mixed signal implementations. We have designed, implemented and tested a fully digital AER convolution pixel. This pixel will be used to implement a full AER convolution chip for programmable kernel image convolution processing.

Comparison of low confinement mode transport simulations using the mixed Bohm/gyro-Bohm and the Multi-Mode-95 transport model

International Nuclear Information System (INIS)

Onjun, Thawatchai; Bateman, Glenn; Kritz, Arnold H.; Hannum, David

2001-01-01

Predictive transport simulations using the mixed Bohm/gyro-Bohm (JET) transport model [M. Erba , Plasma Phys. Controlled Fusion 39, 261 (1997)] are compared with simulations using the Multi-Mode-95 (MMM95) transport model [G. Bateman , Phys. Plasmas 5, 1793 (1998)]. Temperature and density profiles from these simulations are compared with experimental data for 13 low confinement mode (L-mode) discharges from the Doublet III-D Tokamak (DIII-D) [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] and the Tokamak Fusion Test Reactor (TFTR) [D. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The selected discharges include systematic scans over gyro-radius, plasma power, current, and density. It is found that simulations using the two models match experimental data equally well, in spite of the fact that the JET model has predominantly Bohm scaling (proportional to gyro-radius) while the MMM95 model has a purely gyro-Bohm scaling (proportional to gyro-radius squared)

Mode Theory of Multi-Armed Spiral Antennas and Its Application to Electronic Warfare Antennas

Science.gov (United States)

Radway, Matthew J.

Since their invention about 55 years ago, spiral antennas have earned a reputation for providing stable impedance and far-field patterns over multi-decade frequency ranges. For the first few decades these antennas were researched for electronic warfare receiving applications, primarily in the 2-18 GHz range. This research was often done under conditions of secrecy, and often by private contractors who did not readily share their research, and now have been defunct for decades. Even so, the body of literature on the two-armed variant of these antennas is rich, often leading non-specialists to the misconception that these antennas are completely understood. Furthermore, early work was highly experimental in nature, and was conducted before modern data collection and postprocessing capabilities were widespread, which limited the range of the studies. Recent research efforts have focused on extending the application of spirals into new areas, as well as applying exotic materials to `improve' their performance and reduce their size. While interesting results have been obtained, in most instances these were incomplete, often compromising the frequency independent nature of these antennas. This thesis expands the role of the multi-armed spiral outside of its traditional niche of receive-only monopulse direction finding. As a first step, careful study of the spiral-antenna mode theory is undertaken with particular attention paid to the concepts of mode filtering and modal decomposition. A technique for reducing the modal impedance of high arm-count spirals is introduced. The insights gained through this theoretical study are first used to improve the far-field performance of the coiled-arm spiral antenna. Specifically, expanding the number of arms on a coiled arm spiral from two to four while providing proper excitation enables dramatically improved broadside axial ratio and azimuthal pattern uniformity. The multiarming technique is then applied to the design of an antenna

A Perspective on the Numerical and Experimental Characteristics of Multi-Mode Dry-Friction Whip and Whirl

National Research Council Canada - National Science Library

Wilkes, Jason C

2008-01-01

.... Efforts of the author, Dyck [1], Pavalek [2], and coworkers enabled the design and construction of a test rig that demonstrated and recorded accurately the character of multi-mode dry-friction whip and whirl...

Photodetectors for the Advanced Gamma-ray Imaging System (AGIS)

Science.gov (United States)

Wagner, Robert G.; Advanced Gamma-ray Imaging System AGIS Collaboration

2010-03-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation very high energy gamma-ray observatory. Design goals include an order of magnitude better sensitivity, better angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Each telescope is equipped with a camera that detects and records the Cherenkov-light flashes from air showers. The camera is comprised of a pixelated focal plane of blue sensitive and fast (nanosecond) photon detectors that detect the photon signal and convert it into an electrical one. Given the scale of AGIS, the camera must be reliable and cost effective. The Schwarzschild-Couder optical design yields a smaller plate scale than present-day Cherenkov telescopes, enabling the use of more compact, multi-pixel devices, including multianode photomultipliers or Geiger avalanche photodiodes. We present the conceptual design of the focal plane for the camera and results from testing candidate! focal plane sensors.

First operation of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout

International Nuclear Information System (INIS)

Alemi, M.; Campbell, M.; Gys, T.; Mikulec, B.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R.; Snoeys, W.; Wyllie, K.

2000-01-01

We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface

First operation of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout

Energy Technology Data Exchange (ETDEWEB)

Alemi, M.; Campbell, M.; Gys, T. E-mail: thierry.gys@cern.ch; Mikulec, B.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R.; Snoeys, W.; Wyllie, K

2000-07-11

We report on the first operation of a hybrid photon detector prototype with integrated silicon pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment. The photon detector is based on a cross-focussed image intensifier tube geometry where the image is de-magnified by a factor of 4. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The prototype has been characterized using a low-intensity light-emitting diode operated in pulsed mode. Its performance in terms of single-photoelectron detection efficiency and imaging properties is presented. A model of photoelectron detection is proposed, and is shown to be in good agreement with the experimental data. It includes an estimate of the charge signal generated in the silicon detector, and the combined effects of the comparator threshold spread of the pixel readout chip, charge sharing at the pixel boundaries and back-scattering of the photoelectrons at the silicon detector surface.

[The research on bidirectional reflectance computer simulation of forest canopy at pixel scale].

Science.gov (United States)

Song, Jin-Ling; Wang, Jin-Di; Shuai, Yan-Min; Xiao, Zhi-Qiang

2009-08-01

Computer simulation is based on computer graphics to generate the realistic 3D structure scene of vegetation, and to simulate the canopy regime using radiosity method. In the present paper, the authors expand the computer simulation model to simulate forest canopy bidirectional reflectance at pixel scale. But usually, the trees are complex structures, which are tall and have many branches. So there is almost a need for hundreds of thousands or even millions of facets to built up the realistic structure scene for the forest It is difficult for the radiosity method to compute so many facets. In order to make the radiosity method to simulate the forest scene at pixel scale, in the authors' research, the authors proposed one idea to simplify the structure of forest crowns, and abstract the crowns to ellipsoids. And based on the optical characteristics of the tree component and the characteristics of the internal energy transmission of photon in real crown, the authors valued the optical characteristics of ellipsoid surface facets. In the computer simulation of the forest, with the idea of geometrical optics model, the gap model is considered to get the forest canopy bidirectional reflectance at pixel scale. Comparing the computer simulation results with the GOMS model, and Multi-angle Imaging SpectroRadiometer (MISR) multi-angle remote sensing data, the simulation results are in agreement with the GOMS simulation result and MISR BRF. But there are also some problems to be solved. So the authors can conclude that the study has important value for the application of multi-angle remote sensing and the inversion of vegetation canopy structure parameters.

First large DEPFET pixel modules for the Belle II Pixel Detector

Energy Technology Data Exchange (ETDEWEB)

Mueller, Felix; Avella, Paola; Kiesling, Christian; Koffmane, Christian; Moser, Hans-Guenther; Valentan, Manfred [Max-Planck-Institut fuer Physik, Muenchen (Germany); Andricek, Ladislav; Richter, Rainer [Halbleiterlabor der Max-Planck-Gesellschaft, Muenchen (Germany); Collaboration: Belle II-Collaboration

2016-07-01

DEPFET pixel detectors offer excellent signal to noise ratio, resolution and low power consumption with a low material budget. They will be used at Belle II and are a candidate for an ILC vertex detector. The pixels are integrated in a monolithic piece of silicon which also acts as PCB providing the signal and control routings for the ASICs on top. The first prototype DEPFET sensor modules for Belle II have been produced. The modules have 192000 pixels and are equipped with SMD components and three different kinds of ASICs to control and readout the pixels. The entire readout chain has to be studied; the metal layer interconnectivity and routings need to be verified. The modules are fully characterized, and the operation voltages and control sequences of the ASICs are investigated. An overview of the DEPFET concept and first characterization results is presented.

Multi-mode energy management strategy for fuel cell electric vehicles based on driving pattern identification using learning vector quantization neural network algorithm

Science.gov (United States)

Song, Ke; Li, Feiqiang; Hu, Xiao; He, Lin; Niu, Wenxu; Lu, Sihao; Zhang, Tong

2018-06-01

The development of fuel cell electric vehicles can to a certain extent alleviate worldwide energy and environmental issues. While a single energy management strategy cannot meet the complex road conditions of an actual vehicle, this article proposes a multi-mode energy management strategy for electric vehicles with a fuel cell range extender based on driving condition recognition technology, which contains a patterns recognizer and a multi-mode energy management controller. This paper introduces a learning vector quantization (LVQ) neural network to design the driving patterns recognizer according to a vehicle's driving information. This multi-mode strategy can automatically switch to the genetic algorithm optimized thermostat strategy under specific driving conditions in the light of the differences in condition recognition results. Simulation experiments were carried out based on the model's validity verification using a dynamometer test bench. Simulation results show that the proposed strategy can obtain better economic performance than the single-mode thermostat strategy under dynamic driving conditions.

Pixel Experiments

DEFF Research Database (Denmark)

Petersen, Kjell Yngve; Søndergaard, Karin; Augustesen, Christina

2015-01-01

Pixel Experiments The term pixel is traditionally defined as any of the minute elements that together constitute a larger context or image. A pixel has its own form and is the smallest unit seen within a larger structure. In working with the potentials of LED technology in architectural lighting...... lighting design in practice, one quickly experiences and realises that there are untapped potentials in the attributes of LED technology. In this research, speculative studies have been made working with the attributes of LEDs in architectural contexts, with the ambition to ascertain new strategies...... for using LED lighting in lighting design practice. The speculative experiments that have been set-up have aimed to clarify the variables that can be used as parameters in the design of lighting applications; including, for example, the structuring and software control of light. The experiments also...

Long-term lumen depreciation behavior and failure modes of multi-die array LEDs

Science.gov (United States)

Jayawardena, Asiri; Marcus, Daniel; Prugue, Ximena; Narendran, Nadarajah

2013-09-01

One of the main advantages of multi-die array light-emitting diodes (LEDs) is their high flux density. However, a challenge for using such a product in lighting fixture applications is the heat density and the need for thermal management to keep the junction temperatures of all the dies low for long-term reliable performance. Ten multi-die LED array samples for each product from four different manufacturers were subjected to lumen maintenance testing (as described in IES-LM-80-08), and their resulting lumen depreciation and failure modes were studied. The products were tested at the maximum case (or pin) temperature reported by the respective manufacturer by appropriately powering the LEDs. In addition, three samples for each product from two different manufacturers were subjected to rapid thermal cycling, and the resulting lumen depreciation and failure modes were studied. The results showed that the exponential lumen decay model using long-term lumen maintenance data as recommended in IES TM-21 does not fit for all package types. The failure of a string of dies and single die failure in a string were observed in some of the packages.

Modeling of Pixelated Detector in SPECT Pinhole Reconstruction.

Science.gov (United States)

Feng, Bing; Zeng, Gengsheng L

2014-04-10

A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO 2 ) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts.

Whimsicality of multi-mode Hasegawa space-charge waves in a complex plasma containing collision-dominated electrons and streaming ions

Science.gov (United States)

Lee, Myoung-Jae; Jung, Young-Dae

2017-09-01

The influence of collision-dominated electrons on multi-mode Hasegawa space-charge waves are investigated in a complex plasma containing streaming ions. The dispersion relation for the multi-mode Hasegawa space-charge wave propagating in a cylindrical waveguide filled with dusty plasma containing collision-dominated electrons and streaming ions is derived by using the fluid equations and Poisson’s equation which lead to a Bessel equation. By the boundary condition, the roots of the Bessel function would characterize the property of space-charge wave propagation. It is found that two solutions exist for wave frequency, which are affected by the radius of waveguide and the roots of the Bessel function. The damping and growing modes are found to be enhanced by an increase of the radius. However, an increase of electron collision frequency would suppress the damping and the growing modes of the propagating space-charge wave in a cylindrical waveguide plasma.

Optical Splitters Based on Self-Imaging Effect in Multi-Mode Waveguide Made by Ion Exchange in Glass

Directory of Open Access Journals (Sweden)

O. Barkman

2013-04-01

Full Text Available Design and modeling of single mode optical multi-mode interference structures with graded refractive index is reported. Several samples of planar optical channel waveguides were obtained by Ag+, Na+ and K+, Na+ one step thermal ion exchange process in molten salt on GIL49 glass substrate and new special optical glass for ion exchange technology. Waveguide properties were measured by optical mode spectroscopy. Obtained data were used for further design and modeling of single mode channel waveguide and subsequently for the design of 1 to 3 multimode interference power splitter in order to improve simulation accuracy. Designs were developed by utilizing finite difference beam propagation method.

Choice of parameters for linear colliders in multi-bunch mode

International Nuclear Information System (INIS)

Claus, J.

1987-01-01

The energy efficiency of a linear collider in multi-bunch mode is calculated for the case that the bunches in each of the two interacting beams are identical in all interaction points, a configuration which can be realized by taking advantage of the beam-beam effect between beams of opposite electric charge. The maximization of the efficiency is discussed, the maximum appears to increase nearly linearly with beam brightness and accelerating gradient, and about quadratically with the length of the ir. The optimum operating frequency for the linacs increases also, while the pulse repetition rate and the beam current needed for fixed luminosity, decrease. The increasing brightness and the decreasing current needed for higher efficiency lead to smaller transverse spotsizes in the crossing points; this imposes tighter tolerances on the relative transverse coordinates of the two beam-axes. Pillbox or similar resonators, excited in the TM01 mode, may be preferable to quadrupoles for transverse focusing, at the high frequencies and gradients that seem desirable, particularly in the final focus. 4 refs., 7 figs

Development of pixellated Ir-TESs

International Nuclear Information System (INIS)

Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Dayanthi, Rathnayaka M.T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

2006-01-01

We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μmx45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES

Self-amplified CMOS image sensor using a current-mode readout circuit

Science.gov (United States)

Santos, Patrick M.; de Lima Monteiro, Davies W.; Pittet, Patrick

2014-05-01

The feature size of the CMOS processes decreased during the past few years and problems such as reduced dynamic range have become more significant in voltage-mode pixels, even though the integration of more functionality inside the pixel has become easier. This work makes a contribution on both sides: the possibility of a high signal excursion range using current-mode circuits together with functionality addition by making signal amplification inside the pixel. The classic 3T pixel architecture was rebuild with small modifications to integrate a transconductance amplifier providing a current as an output. The matrix with these new pixels will operate as a whole large transistor outsourcing an amplified current that will be used for signal processing. This current is controlled by the intensity of the light received by the matrix, modulated pixel by pixel. The output current can be controlled by the biasing circuits to achieve a very large range of output signal levels. It can also be controlled with the matrix size and this permits a very high degree of freedom on the signal level, observing the current densities inside the integrated circuit. In addition, the matrix can operate at very small integration times. Its applications would be those in which fast imaging processing, high signal amplification are required and low resolution is not a major problem, such as UV image sensors. Simulation results will be presented to support: operation, control, design, signal excursion levels and linearity for a matrix of pixels that was conceived using this new concept of sensor.

Measurements of Ultra-Fast single photon counting chip with energy window and 75 μm pixel pitch with Si and CdTe detectors

International Nuclear Information System (INIS)

Maj, P.; Grybos, P.; Kasinski, K.; Koziol, A.; Krzyzanowska, A.; Kmon, P.; Szczygiel, R.; Zoladz, M.

2017-01-01

Single photon counting pixel detectors become increasingly popular in various 2-D X-ray imaging techniques and scientific experiments mainly in solid state physics, material science and medicine. This paper presents architecture and measurement results of the UFXC32k chip designed in a CMOS 130 nm process. The chip consists of about 50 million transistors and has an area of 9.64 mm × 20.15 mm. The core of the IC is a matrix of 128 × 256 pixels of 75 μm pitch. Each pixel contains a CSA, a shaper with tunable gain, two discriminators with correction circuits and two 14-bit ripple counters operating in a normal mode (with energy window), a long counter mode (one 28-bit counter) and a zero-dead time mode. Gain and noise performance were verified with X-ray radiation and with the chip connected to Si (320 μm thick) and CdTe (750 μ m thick) sensors.

Multi-mode excitation of a clamped–clamped microbeam resonator

KAUST Repository

Younis, Mohammad I.

2015-02-18

We present modeling and simulation of the nonlinear dynamics of a microresonator subjected to two-source electrostatic excitation. The resonator is composed of a clamped–clamped beam excited by a DC voltage load superimposed to two AC voltage loads of different frequencies. One frequency is tuned close to the first natural frequency of the beam and the other is close to the third (second symmetric) natural frequency. A multi-mode Galerkin procedure is applied to extract a reduced-order model, which forms the basis of the numerical simulations. Time history response, Poincare’ sections, Fast Fourier Transforms FFT, and bifurcation diagrams are used to reveal the dynamics of the system. The results indicate complex nonlinear phenomena, which include quasiperiodic motion, torus bifurcations, and modulated chaotic attractors.

Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications.

Science.gov (United States)

Vedantham, Srinivasan; Shrestha, Suman; Karellas, Andrew; Shi, Linxi; Gounis, Matthew J; Bellazzini, Ronaldo; Spandre, Gloria; Brez, Alessandro; Minuti, Massimo

2016-05-01

High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54 μm. After resampling to 54 �

The PixFEL project: development of advanced X-ray pixel detectors for application at future FEL facilities

International Nuclear Information System (INIS)

Rizzo, G.; Batignani, G.; Bettarini, S.; Casarosa, G.; Forti, F.; Paladino, A.; Paoloni, E.; Comotti, D.; Grassi, M.; Lodola, L.; Malcovati, P.; Ratti, L.; Vacchi, C.; Fabris, L.; Manghisoni, M.; Re, V.; Traversi, G.; Morsani, F.; Betta, G.-F. Dalla; Pancheri, L.

2015-01-01

The PixFEL project aims to develop an advanced X-ray camera for imaging suited for the demanding requirements of next generation free electron laser (FEL) facilities. New technologies can be deployed to boost the performance of imaging detectors as well as future pixel devices for tracking. In the first phase of the PixFEL project, approved by the INFN, the focus will be on the development of the microelectronic building blocks, carried out with a 65 nm CMOS technology, implementing a low noise analog front-end channel with high dynamic range and compression features, a low power ADC and high density memory. At the same time PixFEL will investigate and implement some of the enabling technologies to assembly a seamless large area X-ray camera composed by a matrix of multilayer four-side buttable tiles. A pixel matrix with active edge will be developed to minimize the dead area of the sensor layer. Vertical interconnection of two CMOS tiers will be explored to build a four-side buttable readout chip with small pixel pitch and all the on-board required functionalities. The ambitious target requirements of the new pixel device are: single photon resolution, 1 to 10 4 photons @ 1 keV to 10 keV input dynamic range, 10-bit analog to digital conversion up to 5 MHz, 1 kevent in-pixel memory and 100 μm pixel pitch. The long term goal of PixFEL will be the development of a versatile X-ray camera to be operated either in burst mode (European XFEL), or in continuous mode to cope with the high frame rates foreseen for the upgrade phase of the LCLS-II at SLAC

Efficient phase contrast imaging in STEM using a pixelated detector. Part 1: Experimental demonstration at atomic resolution

Energy Technology Data Exchange (ETDEWEB)

Pennycook, Timothy J., E-mail: tpennycook@gmail.com [EPSRC SuperSTEM Facility, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Lupini, Andrew R. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37830 (United States); Yang, Hao [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Murfitt, Matthew F. [Nion Co., 1102 8th St., Kirkland, WA 98033 (United States); Jones, Lewys [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D. [EPSRC SuperSTEM Facility, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

2015-04-15

We demonstrate a method to achieve high efficiency phase contrast imaging in aberration corrected scanning transmission electron microscopy (STEM) with a pixelated detector. The pixelated detector is used to record the Ronchigram as a function of probe position which is then analyzed with ptychography. Ptychography has previously been used to provide super-resolution beyond the diffraction limit of the optics, alongside numerically correcting for spherical aberration. Here we rely on a hardware aberration corrector to eliminate aberrations, but use the pixelated detector data set to utilize the largest possible volume of Fourier space to create high efficiency phase contrast images. The use of ptychography to diagnose the effects of chromatic aberration is also demonstrated. Finally, the four dimensional dataset is used to compare different bright field detector configurations from the same scan for a sample of bilayer graphene. Our method of high efficiency ptychography produces the clearest images, while annular bright field produces almost no contrast for an in-focus aberration-corrected probe. - Highlights: • Ptychographic high efficiency phase contrast imaging is demonstrated in STEM. • We rely on a hardware aberration corrector to eliminate aberrations. • High efficiency is achieved by collecting all the relevant interference. • Use of a pixelated detector allows comparison of bright field modes post acquisition. • Ptychography provides the clearest images among the STEM bright field modes tested.

Multi-Fault Diagnosis of Rolling Bearings via Adaptive Projection Intrinsically Transformed Multivariate Empirical Mode Decomposition and High Order Singular Value Decomposition.

Science.gov (United States)

Yuan, Rui; Lv, Yong; Song, Gangbing

2018-04-16

Rolling bearings are important components in rotary machinery systems. In the field of multi-fault diagnosis of rolling bearings, the vibration signal collected from single channels tends to miss some fault characteristic information. Using multiple sensors to collect signals at different locations on the machine to obtain multivariate signal can remedy this problem. The adverse effect of a power imbalance between the various channels is inevitable, and unfavorable for multivariate signal processing. As a useful, multivariate signal processing method, Adaptive-projection has intrinsically transformed multivariate empirical mode decomposition (APIT-MEMD), and exhibits better performance than MEMD by adopting adaptive projection strategy in order to alleviate power imbalances. The filter bank properties of APIT-MEMD are also adopted to enable more accurate and stable intrinsic mode functions (IMFs), and to ease mode mixing problems in multi-fault frequency extractions. By aligning IMF sets into a third order tensor, high order singular value decomposition (HOSVD) can be employed to estimate the fault number. The fault correlation factor (FCF) analysis is used to conduct correlation analysis, in order to determine effective IMFs; the characteristic frequencies of multi-faults can then be extracted. Numerical simulations and the application of multi-fault situation can demonstrate that the proposed method is promising in multi-fault diagnoses of multivariate rolling bearing signal.

Real-time scene and signature generation for ladar and imaging sensors

Science.gov (United States)

Swierkowski, Leszek; Christie, Chad L.; Antanovskii, Leonid; Gouthas, Efthimios

2014-05-01

This paper describes development of two key functionalities within the VIRSuite scene simulation program, broadening its scene generation capabilities and increasing accuracy of thermal signatures. Firstly, a new LADAR scene generation module has been designed. It is capable of simulating range imagery for Geiger mode LADAR, in addition to the already existing functionality for linear mode systems. Furthermore, a new 3D heat diffusion solver has been developed within the VIRSuite signature prediction module. It is capable of calculating the temperature distribution in complex three-dimensional objects for enhanced dynamic prediction of thermal signatures. With these enhancements, VIRSuite is now a robust tool for conducting dynamic simulation for missiles with multi-mode seekers.

How many pixels does it take to make a good 4"×6" print? Pixel count wars revisited

Science.gov (United States)

Kriss, Michael A.

2011-01-01

In the early 1980's the future of conventional silver-halide photographic systems was of great concern due to the potential introduction of electronic imaging systems then typified by the Sony Mavica analog electronic camera. The focus was on the quality of film-based systems as expressed in the number of equivalent number pixels and bits-per-pixel, and how many pixels would be required to create an equivalent quality image from a digital camera. It was found that 35-mm frames, for ISO 100 color negative film, contained equivalent pixels of 12 microns for a total of 18 million pixels per frame (6 million pixels per layer) with about 6 bits of information per pixel; the introduction of new emulsion technology, tabular AgX grains, increased the value to 8 bit per pixel. Higher ISO speed films had larger equivalent pixels, fewer pixels per frame, but retained the 8 bits per pixel. Further work found that a high quality 3.5" x 5.25" print could be obtained from a three layer system containing 1300 x 1950 pixels per layer or about 7.6 million pixels in all. In short, it became clear that when a digital camera contained about 6 million pixels (in a single layer using a color filter array and appropriate image processing) that digital systems would challenge and replace conventional film-based system for the consumer market. By 2005 this became the reality. Since 2005 there has been a "pixel war" raging amongst digital camera makers. The question arises about just how many pixels are required and are all pixels equal? This paper will provide a practical look at how many pixels are needed for a good print based on the form factor of the sensor (sensor size) and the effective optical modulation transfer function (optical spread function) of the camera lens. Is it better to have 16 million, 5.7-micron pixels or 6 million 7.8-micron pixels? How does intrinsic (no electronic boost) ISO speed and exposure latitude vary with pixel size? A systematic review of these issues will

Development of pixellated Ir-TESs

Science.gov (United States)

Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Damayanthi, Rathnayaka M. T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

2006-04-01

We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μm×45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES.

Propagation velocity of an avalanche along the anode wire in a Geiger-Mueller counter filled with Q-gas at 1 ATM

International Nuclear Information System (INIS)

Matsuda, Kazunori; Sanada, Junpei

1990-01-01

Simple methods were applied to investigate the characteristics of a Geiger-Mueller counter with Q-gas flowing at 1 atm. The propagation velocity of the photon-aided avalanche along the anode wire depends linearly on the strength of the electric field in the counter. Its fluctuation (FWHM) as a function of distance between the source position and the end point is discussed. (orig.)

Simulations of Multi Combustion Modes Hydrogen Engines for Heavy Duty Trucks

Directory of Open Access Journals (Sweden)

Alberto A. Boretti

2012-01-01

Full Text Available The paper presents the numerical study of a diesel direct injection heavy duty truck engine converted to hydrogen. The engine has a power turbine connected through a clutch and a continuously variable transmission to the crankshaft. The power turbine may be disconnected and by-passed when it is inefficient or inconvenient to use. The conversion is obtained by replacing the Diesel injector with a hydrogen injector and the glow plug with a jet ignition device. The hydrogen engine operates different modes of combustion depending on the relative phasing of the main injection and the jet ignition. The engine generally operates mostly in Diesel-like mode, with the most part of the main injection following the suitable creation in cylinder conditions by jet ignition. For medium-low loads, better efficienciy is obtained with the gasoline-like mode jet igniting the premixed homogeneous mixture at top dead centre. It’s permitted at higher loads or at very low loads for the excessive peak pressure or the mixture too lean to burn rapidly. The hydrogen engine has better efficiency than Diesel outputs and fuel conversion. Thanks to the larger rate of heat release, it has the opportunity to run closer to stoichiometry and the multi mode capabilities. The critical area for this engine development is found in the design of a hydrogen injector delivering the amount of fuel needed to the large volume cylinder within a Diesel-like injection time.

Versatile, reprogrammable area pixel array detector for time-resolved synchrotron x-ray applications

Energy Technology Data Exchange (ETDEWEB)

Gruner, Sol [Cornell Univ., Ithaca, NY (United States)

2010-05-01

The final technical report for DOE grant DE-SC0004079 is presented. The goal of the grant was to perform research, development and application of novel imaging x-ray detectors so as to effectively utilize the high intensity and brightness of the national synchrotron radiation facilities to enable previously unfeasible time-resolved x-ray research. The report summarizes the development of the resultant imaging x-ray detectors. Two types of detector platforms were developed: The first is a detector platform (called a Mixed-Mode Pixel Array Detector, or MM-PAD) that can image continuously at over a thousand images per second while maintaining high efficiency for wide dynamic range signals ranging from 1 to hundreds of millions of x-rays per pixel per image. Research on an even higher dynamic range variant is also described. The second detector platform (called the Keck Pixel Array Detector) is capable of acquiring a burst of x-ray images at a rate of millions of images per second.

Mode-synthesizing atomic force microscopy and mode-synthesizing sensing

Science.gov (United States)

Passain, Ali; Thundat, Thomas George; Tetard, Laurene

2014-07-22

A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

Mode synthesizing atomic force microscopy and mode-synthesizing sensing

Science.gov (United States)

Passian, Ali; Thundat, Thomas George; Tetard, Laurene

2013-05-17

A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

A hybrid 3D LIDAR imager based on pixel-by-pixel scanning and DS-OCDMA

Science.gov (United States)

Kim, Gunzung; Eom, Jeongsook; Park, Yongwan

2016-03-01

We propose a new hybrid 3D light detection and ranging (LIDAR) system, which measures a scene with 1280 x 600 pixels at a refresh rate of 60fps. The emitted pulses of each pixel are modulated by direct sequence optical code division multiple access (DS-OCDMA) techniques. The modulated pulses include a unique device identification number, the pixel position in the line, and a checksum. The LIDAR emits the modulated pulses periodically without waiting to receive returning light at the detector. When all the pixels are completely through the process, the travel time, amplitude, width, and speed are used by the pixel-by-pixel scanning LIDAR imager to generate point cloud data as the measured results. We programmed the entire hybrid 3D LIDAR operation in a simulator to observe the functionality accomplished by our proposed model.

Low complexity pixel-based halftone detection

Science.gov (United States)

Ok, Jiheon; Han, Seong Wook; Jarno, Mielikainen; Lee, Chulhee

2011-10-01

With the rapid advances of the internet and other multimedia technologies, the digital document market has been growing steadily. Since most digital images use halftone technologies, quality degradation occurs when one tries to scan and reprint them. Therefore, it is necessary to extract the halftone areas to produce high quality printing. In this paper, we propose a low complexity pixel-based halftone detection algorithm. For each pixel, we considered a surrounding block. If the block contained any flat background regions, text, thin lines, or continuous or non-homogeneous regions, the pixel was classified as a non-halftone pixel. After excluding those non-halftone pixels, the remaining pixels were considered to be halftone pixels. Finally, documents were classified as pictures or photo documents by calculating the halftone pixel ratio. The proposed algorithm proved to be memory-efficient and required low computation costs. The proposed algorithm was easily implemented using GPU.

Multi-spectral Image Analysis for Astaxanthin Coating Classification

DEFF Research Database (Denmark)

Ljungqvist, Martin Georg; Ersbøll, Bjarne Kjær; Nielsen, Michael Engelbrecht

2011-01-01

Industrial quality inspection using image analysis on astaxanthin coating in aquaculture feed pellets is of great importance for automatic production control. In this study multi-spectral image analysis of pellets was performed using LDA, QDA, SNV and PCA on pixel level and mean value of pixels...

THE KEPLER PIXEL RESPONSE FUNCTION

International Nuclear Information System (INIS)

Bryson, Stephen T.; Haas, Michael R.; Dotson, Jessie L.; Koch, David G.; Borucki, William J.; Tenenbaum, Peter; Jenkins, Jon M.; Chandrasekaran, Hema; Caldwell, Douglas A.; Klaus, Todd; Gilliland, Ronald L.

2010-01-01

Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point-spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal-to-noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.

Time-resolved and position-resolved X-ray spectrometry with a pixelated detector

Energy Technology Data Exchange (ETDEWEB)

Sievers, Peter

2012-12-07

The aim of the work presented here was to measure X-ray spectra with a pixelated detector. Due to effects in the sensor the spectrum cannot be measured directly and has to be calculated by a deconvolution of the measured data. In the scope of this work the deconvolution of the measured spectra could be enhanced considerably by - amongst other things - the introduction of the Bayesian deconvolution method. Those improvements opened the possibilities for further measurements. For the measurements the detectors of the Medipix family have been used. They are nowadays used for a wide range of applications and scientific research. Their main advantage is the very high position resolution gained by a pixel pitch of 55 μm and a high number of 65536 pixels. The Timepix detector has, in particular, two special possibilities of measurement: the ToA mode and the ToT mode. In ToA mode the arrival time of an impinging photon is measured and in ToT mode the amount of deposited charge is measured. The most common method of operation is counting the number of impinging photons that release a charge higher than a preset threshold in each pixel. As this released charge is proportional to the energy deposition of the impinging photon, one can perform energy-sensitive measurements. To perform the deconvolution of the measured energy distribution there is a need of an energy response matrix describing the detector response on radiation. For some detectors it is possible to obtain an analytic model of the response functions. Due to the high discrepancy between the impinging spectrum and the measured spectrum in case of detectors of the Medipix family, there is so far no analytic model. Thus, the detector response has to be simulated. As I could improve the precision of the measurement quite extensively, I also intended to tune the simulation with more accurate and appropriate models to gain the same level of accuracy. The results of measurement and simulation have then been compared and

Time-resolved and position-resolved X-ray spectrometry with a pixelated detector

International Nuclear Information System (INIS)

Sievers, Peter

2012-01-01

The aim of the work presented here was to measure X-ray spectra with a pixelated detector. Due to effects in the sensor the spectrum cannot be measured directly and has to be calculated by a deconvolution of the measured data. In the scope of this work the deconvolution of the measured spectra could be enhanced considerably by - amongst other things - the introduction of the Bayesian deconvolution method. Those improvements opened the possibilities for further measurements. For the measurements the detectors of the Medipix family have been used. They are nowadays used for a wide range of applications and scientific research. Their main advantage is the very high position resolution gained by a pixel pitch of 55 μm and a high number of 65536 pixels. The Timepix detector has, in particular, two special possibilities of measurement: the ToA mode and the ToT mode. In ToA mode the arrival time of an impinging photon is measured and in ToT mode the amount of deposited charge is measured. The most common method of operation is counting the number of impinging photons that release a charge higher than a preset threshold in each pixel. As this released charge is proportional to the energy deposition of the impinging photon, one can perform energy-sensitive measurements. To perform the deconvolution of the measured energy distribution there is a need of an energy response matrix describing the detector response on radiation. For some detectors it is possible to obtain an analytic model of the response functions. Due to the high discrepancy between the impinging spectrum and the measured spectrum in case of detectors of the Medipix family, there is so far no analytic model. Thus, the detector response has to be simulated. As I could improve the precision of the measurement quite extensively, I also intended to tune the simulation with more accurate and appropriate models to gain the same level of accuracy. The results of measurement and simulation have then been compared and

Tests of gas sampling electromagnetic shower calorimeter

International Nuclear Information System (INIS)

Barbaro-Galtieri, A.; Carithers, W.; Day, C.; Johnson, K.J.; Wenzel, W.A.; Videau, H.

1983-01-01

An electromagnetic shower gas-sampling calorimeter has been tested in both Geiger and proportional discharge modes for incident electron energies in the range 0.125-16 GeV. The 0.2 radiation length-thick layers were lead-fiberglass laminates with cathode strips normal to the sense wires. The 5x10 mm 2 Geiger cells were formed with uniformly spaced nylon fibers perpendicular to the wires. Proportional mode measurements were carried out in the pressure range 1-10 atm. A Monte Carlo simulation is in good agreement with measured shower characteristics and has been used to predict the behavior for oblique of incidence and for various Geiger cell dimensions. (orig.)

Crack propagation direction in a mixed mode geometry estimated via multi-parameter fracture criteria

Czech Academy of Sciences Publication Activity Database

Malíková, L.; Veselý, V.; Seitl, Stanislav

2016-01-01

Roč. 89, AUG (2016), s. 99-107 ISSN 0142-1123. [International Conference on Characterisation of Crack Tip Fields /3./. Urbino, 20.04.2015-22.04.2015] Institutional support: RVO:68081723 Keywords : Near-crack-tip fields * Mixed mode * Crack propagation direction * Multi-parameter fracture criteria * Finite element analysis Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.899, year: 2016

Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

CERN Document Server

AUTHOR|(SzGeCERN)734627; Benoit, Mathieu; Dannheim, Dominik; Dette, Karola; Hynds, Daniel; Kulis, Szymon; Peric, Ivan; Petric, Marko; Redford, Sophie; Sicking, Eva; Valerio, Pierpaolo

2016-01-01

The vertex detector at the proposed CLIC multi-TeV linear e+e- collider must have minimal material content and high spatial resolution, combined with accurate time-stamping to cope with the expected high rate of beam-induced backgrounds. One of the options being considered is the use of active sensors implemented in a commercial high-voltage CMOS process, capacitively coupled to hybrid pixel ASICs. A prototype of such an assembly, using two custom designed chips (CCPDv3 as active sensor glued to a CLICpix readout chip), has been characterised both in the lab and in beam tests at the CERN SPS using 120 GeV/c positively charged hadrons. Results of these characterisation studies are presented both for single and dual amplification stages in the active sensor. Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

Imaging properties of small-pixel spectroscopic x-ray detectors based on cadmium telluride sensors

International Nuclear Information System (INIS)

Koenig, Thomas; Schulze, Julia; Zuber, Marcus; Rink, Kristian; Oelfke, Uwe; Butzer, Jochen; Hamann, Elias; Cecilia, Angelica; Zwerger, Andreas; Fauler, Alex; Fiederle, Michael

2012-01-01

Spectroscopic x-ray imaging by means of photon counting detectors has received growing interest during the past years. Critical to the image quality of such devices is their pixel pitch and the sensor material employed. This paper describes the imaging properties of Medipix2 MXR multi-chip assemblies bump bonded to 1 mm thick CdTe sensors. Two systems were investigated with pixel pitches of 110 and 165 μm, which are in the order of the mean free path lengths of the characteristic x-rays produced in their sensors. Peak widths were found to be almost constant across the energy range of 10 to 60 keV, with values of 2.3 and 2.2 keV (FWHM) for the two pixel pitches. The average number of pixels responding to a single incoming photon are about 1.85 and 1.45 at 60 keV, amounting to detective quantum efficiencies of 0.77 and 0.84 at a spatial frequency of zero. Energy selective CT acquisitions are presented, and the two pixel pitches' abilities to discriminate between iodine and gadolinium contrast agents are examined. It is shown that the choice of the pixel pitch translates into a minimum contrast agent concentration for which material discrimination is still possible. We finally investigate saturation effects at high x-ray fluxes and conclude with the finding that higher maximum count rates come at the cost of a reduced energy resolution. (paper)

Laser-diode pumped self-mode-locked praseodymium visible lasers with multi-gigahertz repetition rate.

Science.gov (United States)

Zhang, Yuxia; Yu, Haohai; Zhang, Huaijin; Di Lieto, Alberto; Tonelli, Mauro; Wang, Jiyang

2016-06-15

We demonstrate efficient laser-diode pumped multi-gigahertz (GHz) self-mode-locked praseodymium (Pr3+) visible lasers with broadband spectra from green to deep red for the first time to our knowledge. With a Pr3+-doped GdLiF4 crystal, stable self-mode-locked visible pulsed lasers at the wavelengths of 522 nm, 607 nm, 639 nm, and 720 nm have been obtained with the repetition rates of 2.8 GHz, 3.1 GHz, 3.1 GHz, and 3.0 GHz, respectively. The maximum output power was 612 mW with the slope efficiency of 46.9% at 639 nm. The mode-locking mechanism was theoretically analyzed. The stable second-harmonic mode-locking with doubled repetition frequency was also realized based on the Fabry-Perot effect formed in the laser cavity. In addition, we find that the polarization directions were turned with lasing wavelengths. This work may provide a new way for generating efficient ultrafast pulses with high- and changeable-repetition rates in the visible range.

New generation of monolithic active pixel sensors for charged particle detection

International Nuclear Information System (INIS)

Deptuch, G.

2002-09-01

Vertex detectors are of great importance in particle physics experiments, as the knowledge of the event flavour is becoming an issue for the physics programme at Future Linear Colliders. Monolithic Active Pixel Sensors (MAPS) based on a novel detector structure have been proposed. Their fabrication is compatible with a standard CMOS process. The sensor is inseparable from the readout electronics, since both of them are integrated on the same, low-resistivity silicon wafer. The basic pixel configuration comprises only three MOS transistors and a diode collecting the charge through thermal diffusion. The charge is generated in the thin non-depleted epitaxial layer underneath the readout electronics. This approach provides, at low cost, a high resolution and thin device with the whole area sensitive to radiation. Device simulations using the ISE-TCAD package have been carried out to study the charge collection mechanism. In order to demonstrate the viability of the technique, four prototype chips have been fabricated using different submicrometer CMOS processes. The pixel gain has been calibrated using a 55 Fe source and the Poisson sequence method. The prototypes have been exposed to high-energy particle beams at CERN. The tests proved excellent detection performances expressed in a single-track spatial resolution of 1.5 μm and detection efficiency close to 100%, resulting from a SNR ratio of more than 30. Irradiation tests showed immunity of MAPS to a level of a few times 10 12 n/cm 2 and a few hundred kRad of ionising radiation. The ideas for future work, including on-pixel signal amplification, double sampling operation and current mode pixel design are present as well. (author)

A new method to improve multiplication factor in micro-pixel avalanche photodiodes with high pixel density

Energy Technology Data Exchange (ETDEWEB)

Sadygov, Z. [National Nuclear Research Center, Baku (Azerbaijan); Joint Institute for Nuclear Research, Dubna (Russian Federation); Ahmadov, F. [National Nuclear Research Center, Baku (Azerbaijan); Khorev, S. [Zecotek Photonics Inc., Vancouver (Canada); Sadigov, A., E-mail: saazik@yandex.ru [National Nuclear Research Center, Baku (Azerbaijan); Suleymanov, S. [National Nuclear Research Center, Baku (Azerbaijan); Madatov, R.; Mehdiyeva, R. [Institute of Radiation Problems, Baku (Azerbaijan); Zerrouk, F. [Zecotek Photonics Inc., Vancouver (Canada)

2016-07-11

Presented is a new model describing development of the avalanche process in time, taking into account the dynamics of electric field within the depleted region of the diode and the effect of parasitic capacitance shunting individual quenching micro-resistors on device parameters. Simulations show that the effective capacitance of a single pixel, which defines the multiplication factor, is the sum of the pixel capacitance and a parasitic capacitance shunting its quenching micro-resistor. Conclusions obtained as a result of modeling open possibilities of improving the pixel gain in micropixel avalanche photodiodes with high pixel density (or low pixel capacitance).

Development of an X-ray imaging system with SOI pixel detectors

Energy Technology Data Exchange (ETDEWEB)

Nishimura, Ryutaro, E-mail: ryunishi@post.kek.jp [School of High Energy Accelerator Science, SOKENDAI (The Graduate University for Advanced Studies), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Arai, Yasuo; Miyoshi, Toshinobu [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK-IPNS), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Hirano, Keiichi; Kishimoto, Shunji; Hashimoto, Ryo [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK-IMSS), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)

2016-09-21

An X-ray imaging system employing pixel sensors in silicon-on-insulator technology is currently under development. The system consists of an SOI pixel detector (INTPIX4) and a DAQ system based on a multi-purpose readout board (SEABAS2). To correct a bottleneck in the total throughput of the DAQ of the first prototype, parallel processing of the data taking and storing processes and a FIFO buffer were implemented for the new DAQ release. Due to these upgrades, the DAQ throughput was improved from 6 Hz (41 Mbps) to 90 Hz (613 Mbps). The first X-ray imaging system with the new DAQ software release was tested using 33.3 keV and 9.5 keV mono X-rays for three-dimensional computerized tomography. The results of these tests are presented. - Highlights: • The X-ray imaging system employing the SOI pixel sensor is currently under development. • The DAQ of the first prototype has the bottleneck in the total throughput. • The new DAQ release solve the bottleneck by parallel processing and FIFO buffer. • The new DAQ release was tested using 33.3 keV and 9.5 keV mono X-rays.

Photon-counting hexagonal pixel array CdTe detector: Spatial resolution characteristics for image-guided interventional applications

Energy Technology Data Exchange (ETDEWEB)

Vedantham, Srinivasan; Shrestha, Suman; Karellas, Andrew, E-mail: andrew.karellas@umassmed.edu; Shi, Linxi; Gounis, Matthew J. [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States); Bellazzini, Ronaldo; Spandre, Gloria; Brez, Alessandro; Minuti, Massimo [Istituto Nazionale di Fisica Nucleare (INFN), Pisa 56127, Italy and Pixirad Imaging Counters s.r.l., L. Pontecorvo 3, Pisa 56127 (Italy)

2016-05-15

Purpose: High-resolution, photon-counting, energy-resolved detector with fast-framing capability can facilitate simultaneous acquisition of precontrast and postcontrast images for subtraction angiography without pixel registration artifacts and can facilitate high-resolution real-time imaging during image-guided interventions. Hence, this study was conducted to determine the spatial resolution characteristics of a hexagonal pixel array photon-counting cadmium telluride (CdTe) detector. Methods: A 650 μm thick CdTe Schottky photon-counting detector capable of concurrently acquiring up to two energy-windowed images was operated in a single energy-window mode to include photons of 10 keV or higher. The detector had hexagonal pixels with apothem of 30 μm resulting in pixel pitch of 60 and 51.96 μm along the two orthogonal directions. The detector was characterized at IEC-RQA5 spectral conditions. Linear response of the detector was determined over the air kerma rate relevant to image-guided interventional procedures ranging from 1.3 nGy/frame to 91.4 μGy/frame. Presampled modulation transfer was determined using a tungsten edge test device. The edge-spread function and the finely sampled line spread function accounted for hexagonal sampling, from which the presampled modulation transfer function (MTF) was determined. Since detectors with hexagonal pixels require resampling to square pixels for distortion-free display, the optimal square pixel size was determined by minimizing the root-mean-squared-error of the aperture functions for the square and hexagonal pixels up to the Nyquist limit. Results: At Nyquist frequencies of 8.33 and 9.62 cycles/mm along the apothem and orthogonal to the apothem directions, the modulation factors were 0.397 and 0.228, respectively. For the corresponding axis, the limiting resolution defined as 10% MTF occurred at 13.3 and 12 cycles/mm, respectively. Evaluation of the aperture functions yielded an optimal square pixel size of 54 �

Improvements to the power supply and control systems of Geiger-Mueller counter tubes

International Nuclear Information System (INIS)

Gavin, Gerard; Amberny, Philippe.

1977-01-01

This invention aims to provide a power supply and control system for Geiger-Mueller counter tubes requiring only one high voltage output, corresponding to the 'active' phase voltage. With this in view, the invention proposes, inter alia, a system comprising a high voltage source connected to the anode of the GM tube whose cathode is connected to a determination and counting circuit, featuring a cathode connected to the source via an electronic switch and to earth by a component for holding the potential difference at a given level and by another electronic switch, placed in series. The switches are controlled in turn so as alternately to bring the cathode to a first voltage, enabling the tube to function, and to a second voltage, causing the blocking of the tube, this second voltage being set by the component creating the voltage difference [fr

Improvements to the power supply and control systems of Geiger-Mueller counter tubes

Energy Technology Data Exchange (ETDEWEB)

Gavin, G; Amberny, P

1977-10-19

This invention aims to provide a power supply and control system for Geiger-Mueller counter tubes requiring only one high voltage output, corresponding to the 'active' phase voltage. With this in view, the invention proposes, inter alia, a system comprising a high voltage source connected to the anode of the GM tube whose cathode is connected to a determination and counting circuit, featuring a cathode connected to the source via an electronic switch and to earth by a component for holding the potential difference at a given level and by another electronic switch, placed in series. The switches are controlled in turn so as alternately to bring the cathode to a first voltage, enabling the tube to function, and to a second voltage, causing the blocking of the tube, this second voltage being set by the component creating the voltage difference.

A nonlinear multi-mode wideband piezoelectric vibration-based energy harvester using compliant orthoplanar spring

Energy Technology Data Exchange (ETDEWEB)

Dhote, Sharvari, E-mail: sharvari.dhote@mail.utoronto.ca; Zu, Jean; Zhu, Yang [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario M5S-3G8 (Canada)

2015-04-20

In this paper, a nonlinear wideband multi-mode piezoelectric vibration-based energy harvester (PVEH) is proposed based on a compliant orthoplanar spring (COPS), which has an advantage of providing multiple vibration modes at relatively low frequencies. The PVEH is made of a tri-leg COPS flexible structure, where three fixed-guided beams are capable of generating strong nonlinear oscillations under certain base excitation. A prototype harvester was fabricated and investigated through both finite-element analysis and experiments. The frequency response shows multiple resonance which corresponds to a hardening type of nonlinear resonance. By adding masses at different locations on the COPS structure, the first three vibration modes are brought close to each other, where the three hardening nonlinear resonances provide a wide bandwidth for the PVEH. The proposed PVEH has enhanced performance of the energy harvester in terms of a wide frequency bandwidth and a high-voltage output under base excitations.

HgCdTe APD-based linear-mode photon counting components and ladar receivers

Science.gov (United States)

Jack, Michael; Wehner, Justin; Edwards, John; Chapman, George; Hall, Donald N. B.; Jacobson, Shane M.

2011-05-01

Linear mode photon counting (LMPC) provides significant advantages in comparison with Geiger Mode (GM) Photon Counting including absence of after-pulsing, nanosecond pulse to pulse temporal resolution and robust operation in the present of high density obscurants or variable reflectivity objects. For this reason Raytheon has developed and previously reported on unique linear mode photon counting components and modules based on combining advanced APDs and advanced high gain circuits. By using HgCdTe APDs we enable Poisson number preserving photon counting. A metric of photon counting technology is dark count rate and detection probability. In this paper we report on a performance breakthrough resulting from improvement in design, process and readout operation enabling >10x reduction in dark counts rate to ~10,000 cps and >104x reduction in surface dark current enabling long 10 ms integration times. Our analysis of key dark current contributors suggest that substantial further reduction in DCR to ~ 1/sec or less can be achieved by optimizing wavelength, operating voltage and temperature.

HEPS-BPIX, a single photon counting pixel detector with a high frame rate for the HEPS project

Energy Technology Data Exchange (ETDEWEB)

Wei, Wei, E-mail: weiw@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Zhang, Jie; Ning, Zhe; Lu, Yunpeng; Fan, Lei; Li, Huaishen; Jiang, Xiaoshan; Lan, Allan K.; Ouyang, Qun; Wang, Zheng; Zhu, Kejun; Chen, Yuanbo [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Particle Detection and Electronics, Beijing 100049 (China); Liu, Peng [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2016-11-01

China's next generation light source, named the High Energy Photon Source (HEPS), is currently under construction. HEPS-BPIX (HEPS-Beijing PIXel) is a dedicated pixel readout chip that operates in single photon counting mode for X-ray applications in HEPS. Designed using CMOS 0.13 µm technology, the chip contains a matrix of 104×72 pixels. Each pixel measures 150 µm×150 µm and has a counting depth of 20 bits. A bump-bonded prototyping detector module with a 300-µm thick silicon sensor was tested in the beamline of Beijing Synchrotron Radiation Facility. A fast stream of X-ray images was demonstrated, and a frame rate of 1.2 kHz was proven, with a negligible dead time. The test results showed an equivalent noise charge of 115 e{sup −} rms after bump bonding and a threshold dispersion of 55 e{sup −} rms after calibration.

Simulation of a nuclear measurement system around a multi-task mode real-time monitor

International Nuclear Information System (INIS)

De Grandi, G.; Ouiguini, R.

1983-01-01

When debugging and testing material and software for the automation of systems, the non-availability of this last one states important logistic problems. A simulator of the system to be automatized, conceived around a multi-task mode real-time monitor, allowing the debugging of the software of automation without the physical presence of the system to be automatized, is proposed in the present report

Accurate current synchronization trigger mode for multi-framing gated camera on YANG accelerator

International Nuclear Information System (INIS)

Jiang Xiaoguo; Huang Xianbin; Li Chenggang; Yang Libing; Wang Yuan; Zhang Kaizhi; Ye Yi

2007-01-01

The current synchronization trigger mode is important for Z-pinch experiments carried out on the YANG accelerator. The technology can solve the problem of low synchronization precision. The inherent delay time between the load current waveform and the experimental phenomenon can be adopted to obtain the synchronization trigger time. The correlative time precision about ns level can be achieved in this way. The photoelectric isolator and optical fiber are used in the synchronization trigger system to eliminate the electro-magnetic interference and many accurate measurements on the YANG accelerator can be realized. The application of this trigger mode to the multi-framing gated camera synchronization trigger system has done the trick. The evolution course of Z-pinch imploding plasma has been recorded with 3 ns exposure time and 10 ns interframing time. (authors)

Optical Cloud Pixel Recovery via Machine Learning

Directory of Open Access Journals (Sweden)

Subrina Tahsin

2017-05-01

Full Text Available Remote sensing derived Normalized Difference Vegetation Index (NDVI is a widely used index to monitor vegetation and land use change. NDVI can be retrieved from publicly available data repositories of optical sensors such as Landsat, Moderate Resolution Imaging Spectro-radiometer (MODIS and several commercial satellites. Studies that are heavily dependent on optical sensors are subject to data loss due to cloud coverage. Specifically, cloud contamination is a hindrance to long-term environmental assessment when using information from satellite imagery retrieved from visible and infrared spectral ranges. Landsat has an ongoing high-resolution NDVI record starting from 1984. Unfortunately, this long time series NDVI data suffers from the cloud contamination issue. Though both simple and complex computational methods for data interpolation have been applied to recover cloudy data, all the techniques have limitations. In this paper, a novel Optical Cloud Pixel Recovery (OCPR method is proposed to repair cloudy pixels from the time-space-spectrum continuum using a Random Forest (RF trained and tested with multi-parameter hydrologic data. The RF-based OCPR model is compared with a linear regression model to demonstrate the capability of OCPR. A case study in Apalachicola Bay is presented to evaluate the performance of OCPR to repair cloudy NDVI reflectance. The RF-based OCPR method achieves a root mean squared error of 0.016 between predicted and observed NDVI reflectance values. The linear regression model achieves a root mean squared error of 0.126. Our findings suggest that the RF-based OCPR method is effective to repair cloudy pixels and provides continuous and quantitatively reliable imagery for long-term environmental analysis.

LePix-A high resistivity, fully depleted monolithic pixel detector

CERN Document Server

Giubilato, P; Mugnier, H; Bisello, D; Marchioro, A; Snoeys, W; Denes, P; Pantano, D; Rousset, J; Mattiazzo, S; Kloukinas, K; Potenza, A; Rivetti, A; Chalmet, P

2013-01-01

The LePix project explores monolithic pixel sensors fabricated in a 90 nm CMOS technology built over a lightly doped substrate. This approach keeps the advantages usually offered by Monolithic Active Pixel Sensors (MAPS), like a low input capacitance, having a single piece detector and using a standard CMOS production line, and adds the benefit of charge collection by drift from a depleted region several tens of microns deep into the substrate, therefore providing an excellent signal to noise ratio and a radiation tolerance superior to conventional un-depleted MAPS. Such sensors are expected to offer significant cost savings and reduction of power consumption for the same performance, leading to the use of much less material in the detector (less cooling and less copper), addressing one of the main limitations of present day particle tracking systems. The latest evolution of the project uses detectors thinned down to 50 mu m to obtain back illuminated sensors operated in full depletion mode. By back processin...

Hyperspectral tomography based on multi-mode absorption spectroscopy (MUMAS)

Science.gov (United States)

Dai, Jinghang; O'Hagan, Seamus; Liu, Hecong; Cai, Weiwei; Ewart, Paul

2017-10-01

This paper demonstrates a hyperspectral tomographic technique that can recover the temperature and concentration field of gas flows based on multi-mode absorption spectroscopy (MUMAS). This method relies on the recently proposed concept of nonlinear tomography, which can take full advantage of the nonlinear dependency of MUMAS signals on temperature and enables 2D spatial resolution of MUMAS which is naturally a line-of-sight technique. The principles of MUMAS and nonlinear tomography, as well as the mathematical formulation of the inversion problem, are introduced. Proof-of-concept numerical demonstrations are presented using representative flame phantoms and assuming typical laser parameters. The results show that faithful reconstruction of temperature distribution is achievable when a signal-to-noise ratio of 20 is assumed. This method can potentially be extended to simultaneously reconstructing distributions of temperature and the concentration of multiple flame species.

A multi-mode multi-band RF receiver front-end for a TD-SCDMA/LTE/LTE-advanced in 0.18-μm CMOS process

International Nuclear Information System (INIS)

Guo Rui; Zhang Haiying

2012-01-01

A fully integrated multi-mode multi-band directed-conversion radio frequency (RF) receiver front-end for a TD-SCDMA/LTE/LTE-advanced is presented. The front-end employs direct-conversion design, and consists of two differential tunable low noise amplifiers (LNA), a quadrature mixer, and two intermediate frequency (IF) amplifiers. The two independent tunable LNAs are used to cover all the four frequency bands, achieving sufficient low noise and high gain performance with low power consumption. Switched capacitor arrays perform a resonant frequency point calibration for the LNAs. The two LNAs are combined at the driver stage of the mixer, which employs a folded double balanced Gilbert structure, and utilizes PMOS transistors as local oscillator (LO) switches to reduce flicker noise. The front-end has three gain modes to obtain a higher dynamic range. Frequency band selection and mode of configuration is realized by an on-chip serial peripheral interface (SPI) module. The front-end is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.3 mm 2 . The measured double-sideband (DSB) noise figure is below 3.5 dB and the conversion gain is over 43 dB at all of the frequency bands. The total current consumption is 31 mA from a 1.8-V supply. (semiconductor integrated circuits)

Optical readout and control interface for the BTeV pixel vertex detector

CERN Document Server

Vergara-Limon, S; Sheaff, M; Vargas, M A

2002-01-01

Optical links will be used for sending data back and forth from the counting room to the detector in the data acquisition systems for future high energy physics experiments, including ATLAS and CMS in the LHC at CERN (Switzerland) and BTeV at Fermilab (USA). This is because they can be ultra-high speed and are relatively immune to electro-magnetic interference (EMI). The baseline design for the BTeV Pixel Vertex Detector includes two types of optical link, one to control and monitor and the other to read out the hit data from the multi-chip modules on each half-plane of the detector. The design and performance of the first prototype of the Optical Readout and Control Interface for the BTeV Pixel Vertex Detector is described.

Pedagogical Comparison of Five Reactions Performed under Microwave Heating in Multi-Mode versus Mono-Mode Ovens: Diels-Alder Cycloaddition, Wittig Salt Formation, E2 Dehydrohalogenation to Form an Alkyne, Williamson Ether Synthesis, and Fischer Esterification

Science.gov (United States)

Baar, Marsha R.; Gammerdinger, William; Leap, Jennifer; Morales, Erin; Shikora, Jonathan; Weber, Michael H.

2014-01-01

Five reactions were rate-accelerated relative to the standard reflux workup in both multi-mode and mono-mode microwave ovens, and the results were compared to determine whether the sequential processing of a mono-mode unit could provide for better lab logistics and pedagogy. Conditions were optimized so that yields matched in both types of…

Coupling analysis of energy conversion in multi-mode vibration structural control using a synchronized switch damping method

International Nuclear Information System (INIS)

Ji, Hongli; Qiu, Jinhao; Xia, Pinqi; Inman, Daniel

2012-01-01

Modal coupling is an important issue in the analysis and control of structural systems with multi-degrees of freedom (MDOF). In this paper, modal coupling induced by energy conversion in the structural control of an MDOF system using a synchronized switch damping method is investigated theoretically and validated numerically. In the analysis, it is supposed that the voltage on the piezoelectric actuator is switched at the displacement extrema of a given mode. Two types of coupling in energy conversion are considered. The first is whether the switching action based on one mode induces energy conversion of the other modes. The second is whether the vibration of one mode affects the energy conversion of the other modes. The results indicate that the modal coupling in energy conversion is very complicated. In most cases the switching action based on one mode does induce energy conversion of another mode, but the efficiency depends on the frequency ratio of the two modes. The vibration of one mode affects the energy conversion of another mode only when the frequency ratio of the two modes takes some special values. Discussions are also given on the potential application of the theoretical results in the design of an energy harvesting device. (paper)

Determination of pseudo multi-pulse production rate in GM counters by correlation analysis between signal pulses

International Nuclear Information System (INIS)

Hashimoto, Kengo; Ueda, Taizou

1996-01-01

A technique, based on the correlation analysis of signal pulses in time sequence, is proposed to determine the production rate of the pseudo multi-pulse in Geiger-Mueller (GM) counter. With a multi-channel scaler initiated by a signal pulse, subsequent pulses are recorded in sequence. The production of the multi-pulse increases the counting probability immediately after the initiation. By examining the deviation of the measured probability from the ideal counting probability, the production rate and the average lag time to produce the multi-pulse can be determined. By the use of the present technique, the production rate and the average lag time were obtained for the various GM tubes. These results indicate that the consumption of the quench gas results in a significant increase in the production rate but little variation in the lag time, and that the lag time strongly depends on the tube diameter. (author)

Spatial clustering of pixels of a multispectral image

Science.gov (United States)

Conger, James Lynn

2014-08-19

A method and system for clustering the pixels of a multispectral image is provided. A clustering system computes a maximum spectral similarity score for each pixel that indicates the similarity between that pixel and the most similar neighboring. To determine the maximum similarity score for a pixel, the clustering system generates a similarity score between that pixel and each of its neighboring pixels and then selects the similarity score that represents the highest similarity as the maximum similarity score. The clustering system may apply a filtering criterion based on the maximum similarity score so that pixels with similarity scores below a minimum threshold are not clustered. The clustering system changes the current pixel values of the pixels in a cluster based on an averaging of the original pixel values of the pixels in the cluster.

Assembly technology of 4-side buttable MPPC

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, K.; Sato, K.; Yamada, R., E-mail: ryuta-ya@ssd.hpk.co.jp; Hosokawa, N.; Nagano, T.; Hayatsu, K.; Shimohara, T.; Ohkuwa, Y.; Oguri, A.

2013-12-21

The multi-pixel photon counter (MPPC) is a solid-state photon counting device consisting of a Geiger-mode APD and a quenching resistor. Through-silicon via technology (TSV) allows for the production of a discrete array version of the MPPC, creating a detector with the advantages of a larger active area and less dead space in its overall packaging when compared to other package types commonly used to produce MPPCs. Eliminating the need for a wire-bonding pad allows individual MPPCs to be tiled with minimum dead-space between individual detectors to form a four-sided buttable array. Selecting MPPCs that behave and perform very similarly to each other, especially when an operating voltage is applied, minimizes variation in performance between each channel and enhances channel uniformity. The output of discrete arrays of MPPCs can be easily readout with ASICs (application specific integrated circuits) due to their excellent channel uniformity characteristics, with minimum adjustment required by the ASIC. -- Author-Highlights: • TSV-MPPC and assembly technology are developed. • TSV-MPPC array is tiled in 4-sided buttable and has large and dense active area. • The output pulse of MPPC may have sharp rising edge by virtue of TSV. • The uniformity of the array can be maximized by neat inspection technology.

Simulation of Silicon Photomultiplier Signals

Science.gov (United States)

Seifert, Stefan; van Dam, Herman T.; Huizenga, Jan; Vinke, Ruud; Dendooven, Peter; Lohner, Herbert; Schaart, Dennis R.

2009-12-01

In a silicon photomultiplier (SiPM), also referred to as multi-pixel photon counter (MPPC), many Geiger-mode avalanche photodiodes (GM-APDs) are connected in parallel so as to combine the photon counting capabilities of each of these so-called microcells into a proportional light sensor. The discharge of a single microcell is relatively well understood and electronic models exist to simulate this process. In this paper we introduce an extended model that is able to simulate the simultaneous discharge of multiple cells. This model is used to predict the SiPM signal in response to fast light pulses as a function of the number of fired cells, taking into account the influence of the input impedance of the SiPM preamplifier. The model predicts that the electronic signal is not proportional to the number of fired cells if the preamplifier input impedance is not zero. This effect becomes more important for SiPMs with lower parasitic capacitance (which otherwise is a favorable property). The model is validated by comparing its predictions to experimental data obtained with two different SiPMs (Hamamatsu S10362-11-25u and Hamamatsu S10362-33-25c) illuminated with ps laser pulses. The experimental results are in good agreement with the model predictions.

Radiation dose rate meter

International Nuclear Information System (INIS)

Kronenberg, S.; Siebentritt, C.R.

1981-01-01

A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts

Harnessing mode-selective nonlinear optics for on-chip multi-channel all-optical signal processing

Directory of Open Access Journals (Sweden)

Ming Ma

2016-11-01

Full Text Available All-optical signal processing based on nonlinear optical effects allows for the realization of important functions in telecommunications including wavelength conversion, optical multiplexing/demultiplexing, Fourier transformation, and regeneration, amongst others, on ultrafast time scales to support high data rate transmission. In integrated photonic subsystems, the majority of all-optical signal processing systems demonstrated to date typically process only a single channel at a time or perform a single processing function, which imposes a serious limitation on the functionality of integrated solutions. Here, we demonstrate how nonlinear optical effects can be harnessed in a mode-selective manner to perform simultaneous multi-channel (two and multi-functional optical signal processing (i.e., regenerative wavelength conversion in an integrated silicon photonic device. This approach, which can be scaled to a higher number of channels, opens up a new degree of freedom for performing a broad range of multi-channel nonlinear optical signal processing functions using a single integrated photonic device.

Non-linear multi-objective model for planning water-energy modes of Novosibirsk Hydro Power Plant

Science.gov (United States)

Alsova, O. K.; Artamonova, A. V.

2018-05-01

This paper presents a non-linear multi-objective model for planning and optimizing of water-energy modes for the Novosibirsk Hydro Power Plant (HPP) operation. There is a very important problem of developing a strategy to improve the scheme of water-power modes and ensure the effective operation of hydropower plants. It is necessary to determine the methods and criteria for the optimal distribution of water resources, to develop a set of models and to apply them to the software implementation of a DSS (decision-support system) for managing Novosibirsk HPP modes. One of the possible versions of the model is presented and investigated in this paper. Experimental study of the model has been carried out with 2017 data and the task of ten-day period planning from April to July (only 12 ten-day periods) was solved.

Development of a High Dynamic Range Pixel Array Detector for Synchrotrons and XFELs

Science.gov (United States)

Weiss, Joel Todd

Advances in synchrotron radiation light source technology have opened new lines of inquiry in material science, biology, and everything in between. However, x-ray detector capabilities must advance in concert with light source technology to fully realize experimental possibilities. X-ray free electron lasers (XFELs) place particularly large demands on the capabilities of detectors, and developments towards diffraction-limited storage ring sources also necessitate detectors capable of measuring very high flux [1-3]. The detector described herein builds on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging, and the Adaptive Gain Integrating Pixel Detector (AGIPD) developed for the European XFEL by a collaboration between Deustsches Elektronen-Synchrotron (DESY), the Paul-Scherrer-Institute (PSI), the University of Hamburg, and the University of Bonn, led by Heinz Graafsma [4, 5]. The feasibility of combining adaptive gain with charge removal techniques to increase dynamic range in XFEL experiments is assessed by simulating XFEL scatter with a pulsed infrared laser. The strategy is incorporated into pixel prototypes which are evaluated with direct current injection to simulate very high incident x-ray flux. A fully functional 16x16 pixel hybrid integrating x-ray detector featuring several different pixel architectures based on the prototypes was developed. This dissertation describes its operation and characterization. To extend dynamic range, charge is removed from the integration node of the front-end amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is thereby shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to that achieved by counting pixel array detectors, but the integrators presented here are designed to tolerate a

Gas pixel detectors

International Nuclear Information System (INIS)

Bellazzini, R.; Baldini, L.; Brez, A.; Cavalca, F.; Latronico, L.; Massai, M.M.; Minuti, M.; Omodei, N.; Pesce-Rollins, M.; Sgro, C.; Spandre, G.; Costa, E.; Soffitta, P.

2007-01-01

With the Gas Pixel Detector (GPD), the class of micro-pattern gas detectors has reached a complete integration between the gas amplification structure and the read-out electronics. To obtain this goal, three generations of application-specific integrated circuit of increased complexity and improved functionality has been designed and fabricated in deep sub-micron CMOS technology. This implementation has allowed manufacturing a monolithic device, which realizes, at the same time, the pixelized charge-collecting electrode and the amplifying, shaping and charge measuring front-end electronics of a GPD. A big step forward in terms of size and performances has been obtained in the last version of the 0.18 μm CMOS analog chip, where over a large active area of 15x15 mm 2 a very high channel density (470 pixels/mm 2 ) has been reached. On the top metal layer of the chip, 105,600 hexagonal pixels at 50 μm pitch have been patterned. The chip has customable self-trigger capability and includes a signal pre-processing function for the automatic localization of the event coordinates. In this way, by limiting the output signal to only those pixels belonging to the region of interest, it is possible to reduce significantly the read-out time and data volume. In-depth tests performed on a GPD built up by coupling this device to a fine pitch (50 μm) gas electron multiplier are reported. Matching of the gas amplification and read-out pitch has let to obtain optimal results. A possible application of this detector for X-ray polarimetry of astronomical sources is discussed

Dead-time free pixel readout architecture for ATLAS front-end IC

CERN Document Server

Einsweiler, Kevin F; Kleinfelder, S A; Luo, L; Marchesini, R; Milgrome, O; Pengg, F X

1999-01-01

A low power sparse scan readout architecture has been developed for the ATLAS pixel front-end IC. The architecture supports a dual discriminator and extracts the time over threshold (TOT) information along with a 2-D spatial address $9 of the hits associating them with a unique 7-bit beam crossing number. The IC implements level-1 trigger filtering along with event building (grouping together all hits in a beam crossing) in the end of column (EOC) buffer. The $9 events are transmitted over a 40 MHz serial data link with the protocol supporting buffer overflow handling by appending error flags to events. This mixed-mode full custom IC is implemented in 0.8 mu HP process to meet the $9 requirements for the pixel readout in the ATLAS inner detector. The circuits have been tested and the IC provides dead-time-less ambiguity free readout at 40 MHz data rate.

Refractive index sensors based on the fused tapered special multi-mode fiber

Science.gov (United States)

Fu, Xing-hu; Xiu, Yan-li; Liu, Qin; Xie, Hai-yang; Yang, Chuan-qing; Zhang, Shun-yang; Fu, Guang-wei; Bi, Wei-hong

2016-01-01

In this paper, a novel refractive index (RI) sensor is proposed based on the fused tapered special multi-mode fiber (SMMF). Firstly, a section of SMMF is spliced between two single-mode fibers (SMFs). Then, the SMMF is processed by a fused tapering machine, and a tapered fiber structure is fabricated. Finally, a fused tapered SMMF sensor is obtained for measuring external RI. The RI sensing mechanism of tapered SMMF sensor is analyzed in detail. For different fused tapering lengths, the experimental results show that the RI sensitivity can be up to 444.517 81 nm/RIU in the RI range of 1.334 9—1.347 0. The RI sensitivity is increased with the increase of fused tapering length. Moreover, it has many advantages, including high sensitivity, compact structure, fast response and wide application range. So it can be used to measure the solution concentration in the fields of biochemistry, health care and food processing.

Construction techniques and operation principles of Geiger-Mueller counters using external cathode (Mazetype)

International Nuclear Information System (INIS)

Sevegnani, F.X.

1988-01-01

The construction techniques for external cathode (Maze) and internal cathode Geiger-Muller counters are described, showing the operation principles and the used material nature. More than 200 counter types were evaluated analysing their characteristics. The influence of several types of guard-rings was studied, for optimizing counter operation conditions. Plateaus of the order of 700 V with slope of 0,3%/100 V for the net counting rate, and 1400 V with a slope of 0,8/100 V for total counts using total pressure of 10 cmHg, were obtained. A counter for β detection, using blown glass window in one of the edges of the cylinder was constructed. Counters of long life using materials such as, mica, adhesive glues, etc., were obtained. The results shown that the best counter operation occurs when it is empty in a vacuum of 10 -5 mmHg. (M.C.K.) [pt

An application of high vacuum technique: fabrication of Geiger - Mueller counters and measurements of fallout radioactivity in Rio de Janeiro, Brazil, between 1950 and 1960

International Nuclear Information System (INIS)

Gross, B.

1986-01-01

The initial development of vacuum technology, in Brazil, is described. Special attention is given to the fabrication of Geiger-Mueller counters in the period between 1950-1960, abd the results obtained by its use in measurements of radioactivity produced by hydrogen weapons explosions in the atmosphere. (M.C.K.) [pt

ATLAS Pixel Detector Operational Experience

CERN Document Server

Di Girolamo, B; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.9% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Automatic Sub-Pixel Co-Registration of LandSat-8 OLI and Sentinel-2A MSI Images Using Phase Correlation and Machine Learning Based Mapping

Science.gov (United States)

Skakun, Sergii; Roger, Jean-Claude; Vermote, Eric F.; Masek, Jeffrey G.; Justice, Christopher O.

2017-01-01

This study investigates misregistration issues between Landsat-8/OLI and Sentinel-2A/MSI at 30 m resolution, and between multi-temporal Sentinel-2A images at 10 m resolution using a phase correlation approach and multiple transformation functions. Co-registration of 45 Landsat-8 to Sentinel-2A pairs and 37 Sentinel-2A to Sentinel-2A pairs were analyzed. Phase correlation proved to be a robust approach that allowed us to identify hundreds and thousands of control points on images acquired more than 100 days apart. Overall, misregistration of up to 1.6 pixels at 30 m resolution between Landsat-8 and Sentinel-2A images, and 1.2 pixels and 2.8 pixels at 10 m resolution between multi-temporal Sentinel-2A images from the same and different orbits, respectively, were observed. The non-linear Random Forest regression used for constructing the mapping function showed best results in terms of root mean square error (RMSE), yielding an average RMSE error of 0.07+/-0.02 pixels at 30 m resolution, and 0.09+/-0.05 and 0.15+/-0.06 pixels at 10 m resolution for the same and adjacent Sentinel-2A orbits, respectively, for multiple tiles and multiple conditions. A simpler 1st order polynomial function (affine transformation) yielded RMSE of 0.08+/-0.02 pixels at 30 m resolution and 0.12+/-0.06 (same Sentinel-2A orbits) and 0.20+/-0.09 (adjacent orbits) pixels at 10 m resolution.

Depth of interaction and bias voltage depenence of the spectral response in a pixellated CdTe detector operating in time-over-threshold mode subjected to monochromatic X-rays

Science.gov (United States)

Fröjdh, E.; Fröjdh, C.; Gimenez, E. N.; Maneuski, D.; Marchal, J.; Norlin, B.; O'Shea, V.; Stewart, G.; Wilhelm, H.; Modh Zain, R.; Thungström, G.

2012-03-01

High stopping power is one of the most important figures of merit for X-ray detectors. CdTe is a promising material but suffers from: material defects, non-ideal charge transport and long range X-ray fluorescence. Those factors reduce the image quality and deteriorate spectral information. In this project we used a monochromatic pencil beam collimated through a 20μm pinhole to measure the detector spectral response in dependance on the depth of interaction. The sensor was a 1mm thick CdTe detector with a pixel pitch of 110μm, bump bonded to a Timepix readout chip operating in Time-Over-Threshold mode. The measurements were carried out at the Extreme Conditions beamline I15 of the Diamond Light Source. The beam was entering the sensor at an angle of \\texttildelow20 degrees to the surface and then passed through \\texttildelow25 pixels before leaving through the bottom of the sensor. The photon energy was tuned to 77keV giving a variation in the beam intensity of about three orders of magnitude along the beam path. Spectra in Time-over-Threshold (ToT) mode were recorded showing each individual interaction. The bias voltage was varied between -30V and -300V to investigate how the electric field affected the spectral information. For this setup it is worth noticing the large impact of fluorescence. At -300V the photo peak and escape peak are of similar height. For high bias voltages the spectra remains clear throughout the whole depth but for lower voltages as -50V, only the bottom part of the sensor carries spectral information. This is an effect of the low hole mobility and the longer range the electrons have to travel in a low field.

An Anomaly Detector Based on Multi-aperture Mapping for Hyperspectral Data

Directory of Open Access Journals (Sweden)

LI Min

2016-10-01

Full Text Available Considering the correlationship of spectral content between anomaly and clutter background, inaccurate selection of background pixels induced estimation error of background model. In order to solve the above problems, a multi-aperture mapping based anomaly detector was proposed in this paper. Firstly, differing from background model which focused on feature extraction of background, multi-aperture mapping of hyperspectral data characterized the feature of whole hyperspectral data. According to constructed basis set of multi-aperture mapping, anomaly salience index of every test pixel was proposed to measure the relative statistic difference. Secondly, in order to analysis the moderate salience anomaly precisely, membership value was constructed to identify anomaly salience of test pixels continuously based on fuzzy logical theory. At same time, weighted iterative estimation of multi-aperture mapping was expected to converge adaptively with membership value as weight. Thirdly, classical defuzzification was proposed to fuse different detection results. Hyperspectral data was used in the experiments, and the robustness and sensitivity to anomaly with lower silence of proposed detector were tested.

Pixelated coatings and advanced IR coatings

Science.gov (United States)

Pradal, Fabien; Portier, Benjamin; Oussalah, Meihdi; Leplan, Hervé

2017-09-01

Reosc developed pixelated infrared coatings on detector. Reosc manufactured thick pixelated multilayer stacks on IR-focal plane arrays for bi-spectral imaging systems, demonstrating high filter performance, low crosstalk, and no deterioration of the device sensitivities. More recently, a 5-pixel filter matrix was designed and fabricated. Recent developments in pixelated coatings, shows that high performance infrared filters can be coated directly on detector for multispectral imaging. Next generation space instrument can benefit from this technology to reduce their weight and consumptions.

A Medipix2-based imaging system for digital mammography with silicon pixel detectors

CERN Document Server

Bisogni, M G; Fantacci, M E; Mettivier, G; Montesi, M C; Novelli, M; Quattrocchi, M; Rosso, V; Russo, P; Stefanini, A

2004-01-01

In this paper we present the first tests of a digital imaging system based on a silicon pixel detector bump-bonded to an integrated circuit operating in single photon counting mode. The X-rays sensor is a 300 mu m thick silicon, 14 by 14 mm/sup 2/, upon which a matrix of 256 * 256 pixels has been built. The read-out chip, named MEDIPIX2, has been developed at CERN within the MEDIPIX2 Collaboration and it is composed by a matrix of 256 * 256 cells, 55 * 55 mu m/sup 2/. The spatial resolution properties of the system have been assessed by measuring the square wave resolution function (SWRF) and first images of a standard mammographic phantom were acquired using a radiographic tube in the clinical irradiation condition. (5 refs).

The application of low frequency longitudinal guided wave mode for the inspection of multi-hole steel floral pipes

International Nuclear Information System (INIS)

Liu, Z H; Xie, X D; Wu, B; Li, Y H; He, C F

2012-01-01

Shed-pipe grouting technology, an effective advanced supporting method, is often used in the excavation of soft strata. Steel floral pipes are one of the key load-carrying components of shed-pipe grouting supporting structures. Guided waves are a very attractive methodology to inspect multi-hole steel floral pipes as they offer long range inspection capability, mode and frequency tuning, and cost effectiveness. In this contribution, preliminary experiments are described for the inspection of steel floral pipes using a low frequency longitudinal guided wave mode, L(0,2). The relation between the number of grouting holes and the peak-to-peak amplitude of the first end-reflected signal was obtained. The effect of the grouting holes in steel floral pipes on the propagation velocity of the L(0,2) mode at 30 kHz was analyzed. Experimental results indicate that the typical grouting holes in steel floral pipe have no significant effect on the propagation of this mode. As a result, low frequency longitudinal guided wave modes have potential for the non-destructive long range inspection of multi-hole steel floral pipes. Furthermore, the propagation velocity of the investigated L(0,2) mode at 30 kHz decreases linearly with the increase of the number of grouting holes in a steel floral pipe. It is also noticeable that the effect of the grouting holes cumulates along with the increase in the number of grouting holes and subsequent increase in reflection times of longitudinal guided waves in the steel floral pipe. The application potential of the low frequency longitudinal guided wave technique for the inspection of embedded steel floral pipes is discussed.

Evaluation of a hybrid photon counting pixel detector for X-ray polarimetry

International Nuclear Information System (INIS)

Michel, T.; Durst, J.

2008-01-01

It has already been shown in literature that X-ray sensitive CCDs can be used to measure the degree of linear polarization of X-rays using the effect that photoelectrons are emitted with a non-isotropic angular distribution in respect to the orientation of the electric field vector of impinging photons. Up to now hybrid semiconductor pixel detectors like the Timepix-detector have never been used for X-ray polarimetry. The main reason for this is that the pixel pitch is large compared to CCDs which results in a much smaller analyzing power. On the other hand, the active thickness of the sensor layer can be larger than in CCDs leading to an increased efficiency. Therefore hybrid photon counting pixel detectors may be used for imaging and polarimetry at higher photon energies. For irradiation with polarized X-ray photons we were able to measure an asymmetry between vertical and horizontal double hit events in neighboring pixels of the hybrid photon counting Timepix-detector at room temperature. For the specific spectrum used in our experiment an average polarization asymmetry of (0.96±0.02)% was measured. Additionally, the Timepix-detector with its spectroscopic time-over-threshold-mode was used to measure the dependence of the polarization asymmetry on energy deposition in the detector. Polarization asymmetries between 0.2% at 29 keV and 3.4% at 78 keV energy deposition were determined. The results can be reproduced with our EGS4-based Monte-Carlo simulation

PENERAPAN FUZZY ANALYTIC HIERARCHY PROCESS DALAM METODE MULTI ATTRIBUTE FAILURE MODE ANALYSIS UNTUK MENGIDENTIFIKASI PENYEBAB KEGAGALAN POTENSIAL PADA PROSES PRODUKSI

OpenAIRE

Dorina Hetharia

2012-01-01

Banyak metode dalam Total Quality Management (TQM) yang dapat digunakan untuk melakukan perbaikan kualitas produk dan jasa. Salah satunya adalah Multi Attribute Failure Mode Analysis (MAFMA), yang dapat digunakan untuk mengeliminasi atau mengurangi kemungkinan terjadinya kegagalan bila dilihat dari faktor penyebabnya, sehingga dapat mencegah terulang kembali kegagalan tersebut. MAFMA merupakan pengembangan dari Failure Mode and Effect Analysis (FMEA), yang mengintegrasikan atribut severity, o...

Multi-Working Modes Product-Color Planning Based on Evolutionary Algorithms and Swarm Intelligence

Directory of Open Access Journals (Sweden)

Man Ding

2010-01-01

Full Text Available In order to assist designer in color planning during product development, a novel synthesized evaluation method is presented to evaluate color-combination schemes of multi-working modes products (MMPs. The proposed evaluation method considers color-combination images in different working modes as evaluating attributes, to which the corresponding weights are assigned for synthesized evaluation. Then a mathematical model is developed to search for optimal color-combination schemes of MMP based on the proposed evaluation method and two powerful search techniques known as Evolution Algorithms (EAs and Swarm Intelligence (SI. In the experiments, we present a comparative study for two EAs, namely, Genetic Algorithm (GA and Difference Evolution (DE, and one SI algorithm, namely, Particle Swarm Optimization (PSO, on searching for color-combination schemes of MMP problem. All of the algorithms are evaluated against a test scenario, namely, an Arm-type aerial work platform, which has two working modes. The results show that the DE obtains the superior solution than the other two algorithms for color-combination scheme searching problem in terms of optimization accuracy and computation robustness. Simulation results demonstrate that the proposed method is feasible and efficient.

Evaluation of list-mode ordered subset expectation maximization image reconstruction for pixelated solid-state compton gamma camera with large number of channels

Science.gov (United States)

Kolstein, M.; De Lorenzo, G.; Chmeissani, M.

2014-04-01

The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated solid-state technology for nuclear medicine applications. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). For Compton camera, especially with a large number of readout channels, image reconstruction presents a big challenge. In this work, results are presented for the List-Mode Ordered Subset Expectation Maximization (LM-OSEM) image reconstruction algorithm on simulated data with the VIP Compton camera design. For the simulation, all realistic contributions to the spatial resolution are taken into account, including the Doppler broadening effect. The results show that even with a straightforward implementation of LM-OSEM, good images can be obtained for the proposed Compton camera design. Results are shown for various phantoms, including extended sources and with a distance between the field of view and the first detector plane equal to 100 mm which corresponds to a realistic nuclear medicine environment.

Multi-mode interactions in an FEL oscillator

CERN Document Server

Dong Zhi Wei; Masuda, K; Yamazaki, T; Yoshikawa, K

2000-01-01

A 3D time-dependent FEL oscillator simulation code has been developed by using the transverse mode spectral method to analyze interaction among transverse modes. The competition among them in an FEL oscillator was investigated based on the parameters of LANL FEL experiments. It is found that under typical FEL oscillator operation conditions, the TEM sub 0 sub 0 mode is dominant, and the effects of other transverse modes can be negligible.

Characterization of imaging pixel detectors of Si and CdTe read out with the counting X-ray chip MPEC 2.3

International Nuclear Information System (INIS)

Loecker, M.

2007-04-01

Single photon counting detectors with Si- and CdTe-sensors have been constructed and characterized. As readout chip the MPEC 2.3 is used which consists of 32 x 32 pixels with 200 x 200 μm 2 pixel size and which has a high count rate cabability (1 MHz per pixel) as well as a low noise performance (55 e - ). Measurements and simulations of the detector homogeneity are presented. It could be shown that the theoretical maximum of the homogeneity is reached (quantum limit). By means of the double threshold of the MPEC chip the image contrast can be enhanced which is demonstrated by measurement and simulation. Also, multi-chip-modules consisting of 4 MPEC chips and a single Si- or CdTe-sensor have been constructed and successfully operated. With these modules modulation-transfer-function measurements have been done showing a good spatial resolution of the detectors. In addition, multi-chip-modules according to the Sparse-CMOS concept have been built and tests characterizing the interconnection technologies have been performed

Pixels, Blocks of Pixels, and Polygons: Choosing a Spatial Unit for Thematic Accuracy Assessment

Science.gov (United States)

Pixels, polygons, and blocks of pixels are all potentially viable spatial assessment units for conducting an accuracy assessment. We develop a statistical population-based framework to examine how the spatial unit chosen affects the outcome of an accuracy assessment. The populati...

CMS Pixel Detector Upgrade

CERN Document Server

INSPIRE-00038772

2011-01-01

The present Compact Muon Solenoid silicon pixel tracking system has been designed for a peak luminosity of 1034cm-2s-1 and total dose corresponding to two years of the Large Hadron Collider (LHC) operation. With the steady increase of the luminosity expected at the LHC, a new pixel detector with four barrel layers and three endcap disks is being designed. We will present the key points of the design: the new geometry, which minimizes the material budget and increases the tracking points, and the development of a fast digital readout architecture, which ensures readout efficiency even at high rate. The expected performances for tracking and vertexing of the new pixel detector are also addressed.

Hyperspectral Data for Mangrove Species Mapping: A Comparison of Pixel-Based and Object-Based Approach

Directory of Open Access Journals (Sweden)

Muhammad Kamal

2011-10-01

Full Text Available Visual image interpretation and digital image classification have been used to map and monitor mangrove extent and composition for decades. The presence of a high-spatial resolution hyperspectral sensor can potentially improve our ability to differentiate mangrove species. However, little research has explored the use of pixel-based and object-based approaches on high-spatial hyperspectral datasets for this purpose. This study assessed the ability of CASI-2 data for mangrove species mapping using pixel-based and object-based approaches at the mouth of the Brisbane River area, southeast Queensland, Australia. Three mapping techniques used in this study: spectral angle mapper (SAM and linear spectral unmixing (LSU for the pixel-based approaches, and multi-scale segmentation for the object-based image analysis (OBIA. The endmembers for the pixel-based approach were collected based on existing vegetation community map. Nine targeted classes were mapped in the study area from each approach, including three mangrove species: Avicennia marina, Rhizophora stylosa, and Ceriops australis. The mapping results showed that SAM produced accurate class polygons with only few unclassified pixels (overall accuracy 69%, Kappa 0.57, the LSU resulted in a patchy polygon pattern with many unclassified pixels (overall accuracy 56%, Kappa 0.41, and the object-based mapping produced the most accurate results (overall accuracy 76%, Kappa 0.67. Our results demonstrated that the object-based approach, which combined a rule-based and nearest-neighbor classification method, was the best classifier to map mangrove species and its adjacent environments.

Advanced pixel architectures for scientific image sensors

CERN Document Server

Coath, R; Godbeer, A; Wilson, M; Turchetta, R

2009-01-01

We present recent developments from two projects targeting advanced pixel architectures for scientific applications. Results are reported from FORTIS, a sensor demonstrating variants on a 4T pixel architecture. The variants include differences in pixel and diode size, the in-pixel source follower transistor size and the capacitance of the readout node to optimise for low noise and sensitivity to small amounts of charge. Results are also reported from TPAC, a complex pixel architecture with ~160 transistors per pixel. Both sensors were manufactured in the 0.18μm INMAPS process, which includes a special deep p-well layer and fabrication on a high resistivity epitaxial layer for improved charge collection efficiency.

Gossip: Gaseous pixels

Science.gov (United States)

Koffeman, E. N.

2007-12-01

Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a 55Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated.

Gossip: Gaseous pixels

Energy Technology Data Exchange (ETDEWEB)

Koffeman, E.N. [Nikhef, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)], E-mail: d77@nikhef.nl

2007-12-01

Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a {sup 55}Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated.

Gossip: Gaseous pixels

International Nuclear Information System (INIS)

Koffeman, E.N.

2007-01-01

Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a 55 Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated

Research tokamak system with multi-mode discharges using inverter power supply

International Nuclear Information System (INIS)

Kojima, Hiroki; Kobayashi, Masahiro; Takagi, Makoto; Takamura, Shuichi; Tashiro, Kenji

1999-01-01

In Current Sustaining Tokamak in Nagoya university (CSTN)-IV research tokamak system using a compact 40kHz pulse width modulation (PWM) inverter power supply, which is controlled through LabVIEW program, we construct a new tokamak discharge system with multi-mode including a stable alternating current discharge and a high-repetition high-duty one. These discharge modes can be operated continuously for as long as 60sec. The continuous discharge with long duration is able to simulate the important physical and chemical processes of long time discharges in fusion devices, in which the heat load to the wall and the particle balance in the plasma-wall system are crucial topics in order to realize a long pulse fusion reactor, like ITER. Employing ergodic divertor (ED) is one of tools to control the particle balance and the heat load to the wall. In addition, we installed another inverter power supply to generate a rotating magnetic perturbation for dynamic ergodic divertor (DED) with the appropriate measurement system so that we may carry out experiments on heat and particle control with DED at long time operation. (author)

Fuzzy Risk Evaluation in Failure Mode and Effects Analysis Using a D Numbers Based Multi-Sensor Information Fusion Method.

Science.gov (United States)

Deng, Xinyang; Jiang, Wen

2017-09-12

Failure mode and effect analysis (FMEA) is a useful tool to define, identify, and eliminate potential failures or errors so as to improve the reliability of systems, designs, and products. Risk evaluation is an important issue in FMEA to determine the risk priorities of failure modes. There are some shortcomings in the traditional risk priority number (RPN) approach for risk evaluation in FMEA, and fuzzy risk evaluation has become an important research direction that attracts increasing attention. In this paper, the fuzzy risk evaluation in FMEA is studied from a perspective of multi-sensor information fusion. By considering the non-exclusiveness between the evaluations of fuzzy linguistic variables to failure modes, a novel model called D numbers is used to model the non-exclusive fuzzy evaluations. A D numbers based multi-sensor information fusion method is proposed to establish a new model for fuzzy risk evaluation in FMEA. An illustrative example is provided and examined using the proposed model and other existing method to show the effectiveness of the proposed model.

Multi-mode vibration control of piping system

International Nuclear Information System (INIS)

Minowa, Takeshi; Seto, Kazuto; Iiyama, Fumiya; Sodeyama, Hiroshi

1999-01-01

In this paper, dual dynamic absorbers are applied to the piping system in order to control the multiple vibration modes. ANSYS, which is one of the software based on FEM(finite element method), is used for the design of dual dynamic absorbers as well as for the determination of their optimum installing positions. The dual dynamic absorbers designed optimally for controlling the first three vibration modes perform just like a houde damper in higher frequency and have an effect on controlling higher modes. To use this advantage, three dual dynamic absorbers are installed in positions where they influence higher modes, and not only the first three modes of the piping system but also the extensive modes are controlled. Practical experimental study has also been carried out and it is shown that a dual dynamic absorber is suitable for controlling the vibration of the piping system. (author)

Comparison of single-/few-/multi-mode 850 nm VCSELs for optical OFDM transmission.

Science.gov (United States)

Kao, Hsuan-Yun; Tsai, Cheng-Ting; Leong, Shan-Fong; Peng, Chun-Yen; Chi, Yu-Chieh; Huang, Jian Jang; Kuo, Hao-Chung; Shih, Tien-Tsorng; Jou, Jau-Ji; Cheng, Wood-Hi; Wu, Chao-Hsin; Lin, Gong-Ru

2017-07-10

For high-speed optical OFDM transmission applications, a comprehensive comparison of the homemade multi-/few-/single-transverse mode (MM/FM/SM) vertical cavity surface emitting laser (VCSEL) chips is performed. With microwave probe, the direct encoding of pre-leveled 16-QAM OFDM data and transmission over 100-m-long OM4 multi-mode-fiber (MMF) are demonstrated for intra-datacenter applications. The MM VCSEL chip with the largest emission aperture of 11 μm reveals the highest differential quantum efficiency which provides the highest optical power of 8.67 mW but exhibits the lowest encodable bandwidth of 21 GHz. In contrast, the SM VCSEL chip fabricated with the smallest emission aperture of only 3 μm provides the highest 3-dB encoding bandwidth up to 23 GHz at a cost of slight heat accumulation. After optimization, with the trade-off set between the receiving signal-to-noise ratio (SNR) and bandwidth, the FM VCSEL chip guarantees the highest optical OFDM transmission bit rate of 96 Gbit/s under back-to-back case with its strongest throughput. Among three VCSEL chips, the SM VCSEL chip with nearly modal-dispersion free feature is treated as the best candidate for carrying the pre-leveled 16-QAM OFDM data over 100-m OM4-MMF with same material structure but exhibits different oxide-layer confined gain cross-sections with one another at 80-Gbit/s with the smallest receiving power penalty of 1.77 dB.

Pixel 2010: A résumé

CERN Document Server

Wermes, Norbert

2011-01-01

The Pixel 2010 conference focused on semiconductor pixel detectors for particle tracking/vertexing as well as for imaging, in particular for synchrotron light sources and XFELs. The big LHC hybrid pixel detectors have impressively started showing their capabilities. X-ray imaging detectors, also using the hybrid pixel technology, have greatly advanced the experimental possibilities for diffraction experiments. Monolithic or semi-monolithic devices like CMOS active pixels and DEPFET pixels have now reached a state such that complete vertex detectors for RHIC and superKEKB are being built with these technologies. Finally, new advances towards fully monolithic active pixel detectors, featuring full CMOS electronics merged with efficient signal charge collection, exploiting standard CMOS technologies, SOI and/or 3D integration, show the path for the future. This résumé attempts to extract the main statements of the results and developments presented at this conference.

Development and characterization of diamond and 3D-silicon pixel detectors with ATLAS-pixel readout electronics

International Nuclear Information System (INIS)

Mathes, Markus

2008-12-01

Hybrid pixel detectors are used for particle tracking in the innermost layers of current high energy experiments like ATLAS. After the proposed luminosity upgrade of the LHC, they will have to survive very high radiation fluences of up to 10 16 particles per cm 2 per life time. New sensor concepts and materials are required, which promise to be more radiation tolerant than the currently used planar silicon sensors. Most prominent candidates are so-called 3D-silicon and single crystal or poly-crystalline diamond sensors. Using the ATLAS pixel electronics different detector prototypes with a pixel geometry of 400 x 50 μm 2 have been built. In particular three devices have been studied in detail: a 3D-silicon and a single crystal diamond detector with an active area of about 1 cm 2 and a poly-crystalline diamond detector of the same size as a current ATLAS pixel detector module (2 x 6 cm 2 ). To characterize the devices regarding their particle detection efficiency and spatial resolution, the charge collection inside a pixel cell as well as the charge sharing between adjacent pixels was studied using a high energy particle beam. (orig.)

Model predictive control of an air suspension system with damping multi-mode switching damper based on hybrid model

Science.gov (United States)

Sun, Xiaoqiang; Yuan, Chaochun; Cai, Yingfeng; Wang, Shaohua; Chen, Long

2017-09-01

This paper presents the hybrid modeling and the model predictive control of an air suspension system with damping multi-mode switching damper. Unlike traditional damper with continuously adjustable damping, in this study, a new damper with four discrete damping modes is applied to vehicle semi-active air suspension. The new damper can achieve different damping modes by just controlling the on-off statuses of two solenoid valves, which makes its damping adjustment more efficient and more reliable. However, since the damping mode switching induces different modes of operation, the air suspension system with the new damper poses challenging hybrid control problem. To model both the continuous/discrete dynamics and the switching between different damping modes, the framework of mixed logical dynamical (MLD) systems is used to establish the system hybrid model. Based on the resulting hybrid dynamical model, the system control problem is recast as a model predictive control (MPC) problem, which allows us to optimize the switching sequences of the damping modes by taking into account the suspension performance requirements. Numerical simulations results demonstrate the efficacy of the proposed control method finally.

Overview of the CMS Pixel Detector

CERN Document Server

Cerati, Giuseppe B

2008-01-01

The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2009. It will investigate the proton-proton collisions at $14~TeV$. A robust tracking combined with a precise vertex reconstruction is crucial to address the physics challenge of proton collisions at this energy. To this extent an all-silicon tracking system with very fine granularity has been built and now is in the final commissioning phase. It represents the largest silicon tracking detector ever built. The system is composed by an outer part, made of micro-strip detectors, and an inner one, made of pixel detectors. The pixel detector consists of three pixel barrel layers and two forward disks at each side of the interaction region. Each pixel sensor, both for the barrel and forward detectors, has $100 \\times 150$ $\\mu m^2$ cells for a total of 66 million pixels covering a total area of about $1~m^2$. The pixel detector will play a crucial role in the pattern recognition and the track reconstruction both...

Dead pixel replacement in LWIR microgrid polarimeters.

Science.gov (United States)

Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

2007-06-11

LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data.

A 2D 4×4 Channel Readout ASIC for Pixelated CdTe Detectors for Medical Imaging Applications.

Science.gov (United States)

Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Martínez, Ricardo; Puigdengoles, Carles

2015-10-01

We present a 16-channel readout integrated circuit (ROIC) with nanosecond-resolution time to digital converter (TDC) for pixelated Cadmium Telluride (CdTe) gamma-ray detectors. The 4 × 4 pixel array ROIC is the proof of concept of the 10 × 10 pixel array readout ASIC for positron-emission tomography (PET) scanner, positron-emission mammography (PEM) scanner, and Compton gamma camera. The electronics of each individual pixel integrates an analog front-end with switchable gain, an analog to digital converter (ADC), configuration registers, and a 4-state digital controller. For every detected photon, the pixel electronics provides the energy deposited in the detector with 10-bit resolution, and a fast trigger signal for time stamp. The ASIC contains the 16-pixel matrix electronics, a digital controller, five global voltage references, a TDC, a temperature sensor, and a band-gap based current reference. The ASIC has been fabricated with TSMC 0.25 μ m mixed-signal CMOS technology and occupies an area of 5.3 mm × 6.8 mm. The TDC shows a resolution of 95.5 ps, a precision of 600 ps at full width half maximum (FWHM), and a power consumption of 130 μ W. In acquisition mode, the total power consumption of every pixel is 200 μ W. An equivalent noise charge (ENC) of 160 e - RMS at maximum gain and negative polarity conditions has been measured at room temperature.

FACT-The first Cherenkov telescope using a G-APD camera for TeV gamma-ray astronomy

International Nuclear Information System (INIS)

Anderhub, H.; Backes, M.; Biland, A.; Boller, A.; Braun, I.; Bretz, T.; Commichau, S.; Commichau, V.; Domke, M.; Dorner, D.; Gendotti, A.; Grimm, O.; Gunten, H. von; Hildebrand, D.; Horisberger, U.; Koehne, J.-H.; Kraehenbuehl, T.; Kranich, D.; Krumm, B.; Lorenz, E.

2011-01-01

Geiger-mode Avalanche Photodiodes (G-APD) bear the potential to significantly improve the sensitivity of Imaging Air Cherenkov Telescopes (IACT). We are currently building the First G-APD Cherenkov Telescope (FACT) by refurbishing an old IACT with a mirror area of 9.5 square meters and are constructing a new, fine-pixelized camera using novel G-APDs. The main goal is to evaluate the performance of a complete system by observing very high energy gamma-rays from the Crab Nebula. This is an important field test to check the feasibility of G-APD-based cameras to replace at some time the PMT-based cameras of planned future IACTs like AGIS and CTA. In this article, we present the basic design of such a camera as well as some important details.

The Design and Implementation in $0.13\\mu m$ CMOS of an Algorithm Permitting Spectroscopic Imaging with High Spatial Resolution for Hybrid Pixel Detectors

CERN Document Server

Ballabriga, Rafael; Vilasís-Cardona, Xavier

2009-01-01

Advances in pixel detector technology are opening up new possibilities in many fields of science. Modern High Energy Physics (HEP) experiments use pixel detectors in tracking systems where excellent spatial resolution, precise timing and high signal-to-noise ratio are required for accurate and clean track reconstruction. Many groups are working worldwide to adapt the hybrid pixel technology to other fields such as medical X-ray radiography, protein structure analysis or neutron imaging. The Medipix3 chip is a 256x256 channel hybrid pixel detector readout chip working in Single Photon Counting Mode. It has been developed with a new front-end architecture aimed at eliminating the spectral distortion produced by charge diffusion in highly segmented semiconductor detectors. In the new architecture neighbouring pixels communicate with one another. Charges can be summed event-by-event and the incoming quantum can be assigned as a single hit to the pixel with the biggest charge deposit. In the case where incoming X-...

Graphene metamaterial spatial light modulator for infrared single pixel imaging.

Science.gov (United States)

Fan, Kebin; Suen, Jonathan Y; Padilla, Willie J

2017-10-16

High-resolution and hyperspectral imaging has long been a goal for multi-dimensional data fusion sensing applications - of interest for autonomous vehicles and environmental monitoring. In the long wave infrared regime this quest has been impeded by size, weight, power, and cost issues, especially as focal-plane array detector sizes increase. Here we propose and experimentally demonstrated a new approach based on a metamaterial graphene spatial light modulator (GSLM) for infrared single pixel imaging. A frequency-division multiplexing (FDM) imaging technique is designed and implemented, and relies entirely on the electronic reconfigurability of the GSLM. We compare our approach to the more common raster-scan method and directly show FDM image frame rates can be 64 times faster with no degradation of image quality. Our device and related imaging architecture are not restricted to the infrared regime, and may be scaled to other bands of the electromagnetic spectrum. The study presented here opens a new approach for fast and efficient single pixel imaging utilizing graphene metamaterials with novel acquisition strategies.

Gamma radiation damage in pixelated detector based on carbon nanotubes

International Nuclear Information System (INIS)

Leyva, A.; Pinnera, I.; Leyva, D.; Abreu, Y.; Cruz, C. M.

2013-01-01

The aim of this paper is to evaluate the possible gamma radiation damage in high pixelated based on multi-walled carbon nanotubes detectors, grown on two different substrata, when it is operating in aggressive radiational environments. The radiation damage in displacements per atom (dpa) terms were calculated using the MCCM algorithm, which takes into account the McKinley-Feshbach approach with the Kinchin-Pease approximation for the damage function. Was observed that with increasing of the gamma energy the displacement total number grows monotonically reaching values of 0.39 displacements for a 10 MeV incident photon. The profiles of point defects distributions inside the carbon nanotube pixel linearly rise with depth, increasing its slope with photon energy. In the 0.1 MeV - 10 MeV studied energy interval the electron contribution to the total displacement number become higher than the positron ones, reaching this last one a maximum value of 12% for the 10 MeV incident photons. Differences between the calculation results for the two used different substrata were not observed. (Author)

Diagnostic for two-mode variable valve activation device

Science.gov (United States)

Fedewa, Andrew M

2014-01-07

A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

Optimizing strategy for repetitive construction projects within multi-mode resources

Directory of Open Access Journals (Sweden)

Remon Fayek Aziz

2013-03-01

Full Text Available Estimating tender data for specific project is the most essential part in construction areas as of a contractor’s view such as: proposed project duration with corresponding gross value and cash flows. Cash flow analysis of construction projects has a long history and has been an important topic in construction management. Determination of project cash flows is very sensitive, especially for repetitive construction projects. This paper focuses on how to calculate tender data for repetitive construction projects such as: project duration, project cost, project/bid price, project cash flows, project maximum working capital and project net present value that is equivalent to net profit at the beginning of the project. A simplified multi-objective optimization formulation will be presented that creates best tender data to contractor comparing with more feasible options that are generated from multi-mode resources in a given project. This mathematical formulation is intended to give more scenarios which provide a practical support for typical construction contractors who need to optimize resource utilization in order to minimize project duration, project/bid price and project maximum working capital while maximizing its net present value simultaneously. At the end of the paper, an illustrative example will be presented to demonstrate the applications of proposed technique to an optimization expressway of repetitive construction project.

CMS Barrel Pixel Detector Overview

CERN Document Server

Kästli, H C; Erdmann, W; Gabathuler, K; Hörmann, C; Horisberger, Roland Paul; König, S; Kotlinski, D; Meier, B; Robmann, P; Rohe, T; Streuli, S

2007-01-01

The pixel detector is the innermost tracking device of the CMS experiment at the LHC. It is built from two independent sub devices, the pixel barrel and the end disks. The barrel consists of three concentric layers around the beam pipe with mean radii of 4.4, 7.3 and 10.2 cm. There are two end disks on each side of the interaction point at 34.5 cm and 46.5 cm. This article gives an overview of the pixel barrel detector, its mechanical support structure, electronics components, services and its expected performance.

Time displacement pictures with multi-mode probes from circumferential welds

International Nuclear Information System (INIS)

Wustenberg, H.; Jaffrey, D.; Ludwig, B.; Bertus, N.; Erhard, A.

1985-01-01

If a creeping wave probe is applied to butt welds typical echo patterns from weld defects can be received. It seems possible that echoes from the geometric shape of the root or the crown and defect echoes can be separated by simple means. This has been the reason for the development of a special presentation of the echo patterns received by this multi-mode creeping wave probe. The so called time displacement pictures show the AD-converted A-scans in a gray scale along a line corresponding to the time axis of the propagation. Perpendicular to this time axis results obtained from displacement of the probe parallel to the weld are presented. This kind of picture immediately provides the whole A-scan information. This paper presents some first results on simulated welds with artificial defects and on circumferential welds with typical geometric imperfections

CMS has a heart of pixels

CERN Multimedia

2003-01-01

In the immediate vicinity of the collision point, CMS will be equipped with pixel detectors consisting of no fewer than 50 million pixels measuring 150 microns along each side. Each of the pixels, which receive the signal, is connected to its own electronic circuit by a tiny sphere (seen here in the electron microscope image) measuring 15 to 20 microns in diameter.

Development and characterization of diamond and 3D-silicon pixel detectors with ATLAS-pixel readout electronics

Energy Technology Data Exchange (ETDEWEB)

Mathes, Markus

2008-12-15

Hybrid pixel detectors are used for particle tracking in the innermost layers of current high energy experiments like ATLAS. After the proposed luminosity upgrade of the LHC, they will have to survive very high radiation fluences of up to 10{sup 16} particles per cm{sup 2} per life time. New sensor concepts and materials are required, which promise to be more radiation tolerant than the currently used planar silicon sensors. Most prominent candidates are so-called 3D-silicon and single crystal or poly-crystalline diamond sensors. Using the ATLAS pixel electronics different detector prototypes with a pixel geometry of 400 x 50 {mu}m{sup 2} have been built. In particular three devices have been studied in detail: a 3D-silicon and a single crystal diamond detector with an active area of about 1 cm{sup 2} and a poly-crystalline diamond detector of the same size as a current ATLAS pixel detector module (2 x 6 cm{sup 2}). To characterize the devices regarding their particle detection efficiency and spatial resolution, the charge collection inside a pixel cell as well as the charge sharing between adjacent pixels was studied using a high energy particle beam. (orig.)

Analysis of 3D stacked fully functional CMOS Active Pixel Sensor detectors

International Nuclear Information System (INIS)

Passeri, D; Servoli, L; Meroli, S

2009-01-01

The IC technology trend is to move from 3D flexible configurations (package on package, stacked dies) to real 3D ICs. This is mainly due to i) the increased electrical performances and ii) the cost of 3D integration which may be cheaper than to keep shrinking 2D circuits. Perspective advantages for particle tracking and vertex detectors applications in High Energy Physics can be envisaged: in this work, we will focus on the capabilities of the state-of-the-art vertical scale integration technologies, allowing for the fabrication of very compact, fully functional, multiple layers CMOS Active Pixel Sensor (APS) detectors. The main idea is to exploit the features of the 3D technologies for the fabrication of a ''stack'' of very thin and precisely aligned CMOS APS layers, leading to a single, integrated, multi-layers pixel sensor. The adoption of multiple-layers single detectors can dramatically reduce the mass of conventional, separated detectors (thus reducing multiple scattering issues), at the same time allowing for very precise measurements of particle trajectory and momentum. As a proof of concept, an extensive device and circuit simulation activity has been carried out, aiming at evaluate the suitability of such a kind of CMOS active pixel layers for particle tracking purposes.

Charge sharing in silicon pixel detectors

CERN Document Server

Mathieson, K; Seller, P; Prydderch, M L; O'Shea, V; Bates, R L; Smith, K M; Rahman, M

2002-01-01

We used a pixellated hybrid silicon X-ray detector to study the effect of the sharing of generated charge between neighbouring pixels over a range of incident X-ray energies, 13-36 keV. The system is a room temperature, energy resolving detector with a Gaussian FWHM of 265 eV at 5.9 keV. Each pixel is 300 mu m square, 300 mu m deep and is bump bonded to matching read out electronics. The modelling packages MEDICI and MCNP were used to model the complete X-ray interaction and the subsequent charge transport. Using this software a model is developed which reproduces well the experimental results. The simulations are then altered to explore smaller pixel sizes and different X-ray energies. Charge sharing was observed experimentally to be 2% at 13 keV rising to 4.5% at 36 keV, for an energy threshold of 4 keV. The models predict that up to 50% of charge may be lost to the neighbouring pixels, for an X-ray energy of 36 keV, when the pixel size is reduced to 55 mu m.

Sparse PDF maps for non-linear multi-resolution image operations

KAUST Repository

Hadwiger, Markus

2012-11-01

We introduce a new type of multi-resolution image pyramid for high-resolution images called sparse pdf maps (sPDF-maps). Each pyramid level consists of a sparse encoding of continuous probability density functions (pdfs) of pixel neighborhoods in the original image. The encoded pdfs enable the accurate computation of non-linear image operations directly in any pyramid level with proper pre-filtering for anti-aliasing, without accessing higher or lower resolutions. The sparsity of sPDF-maps makes them feasible for gigapixel images, while enabling direct evaluation of a variety of non-linear operators from the same representation. We illustrate this versatility for antialiased color mapping, O(n) local Laplacian filters, smoothed local histogram filters (e.g., median or mode filters), and bilateral filters. © 2012 ACM.

A Multi-Mode Video Driver for a High Resolution LCoS Display

OpenAIRE

Farrell, Ronan; Jacob, Mark; Maher, Roger

2000-01-01

This paper describes the design of a display driver for Liquid Crystal on Silicon (LCoS) microdisplays. These are high resolution reflective display devices which allow up to 1280x1024 pixels on an area of 3.75cm2, and are typically refreshed at 120Hz. The required driver consists of a digital section capable of taking the common display formats such as SVGA and new formats, SXGA, and processing these to a common 120HzRGB signal, requiring an output rate of 160 mega-pixels/second. This signal...

Cyclops: single-pixel imaging lidar system based on compressive sensing

Science.gov (United States)

Magalhães, F.; Correia, M. V.; Farahi, F.; Pereira do Carmo, J.; Araújo, F. M.

2017-11-01

Mars and the Moon are envisaged as major destinations of future space exploration missions in the upcoming decades. Imaging LIDARs are seen as a key enabling technology in the support of autonomous guidance, navigation and control operations, as they can provide very accurate, wide range, high-resolution distance measurements as required for the exploration missions. Imaging LIDARs can be used at critical stages of these exploration missions, such as descent and selection of safe landing sites, rendezvous and docking manoeuvres, or robotic surface navigation and exploration. Despite these devices have been commercially available and used for long in diverse metrology and ranging applications, their size, mass and power consumption are still far from being suitable and attractive for space exploratory missions. Here, we describe a compact Single-Pixel Imaging LIDAR System that is based on a compressive sensing technique. The application of the compressive codes to a DMD array enables compression of the spatial information, while the collection of timing histograms correlated to the pulsed laser source ensures image reconstruction at the ranged distances. Single-pixel cameras have been compared with raster scanning and array based counterparts in terms of noise performance, and proved to be superior. Since a single photodetector is used, a better SNR and higher reliability is expected in contrast with systems using large format photodetector arrays. Furthermore, the event of failure of one or more micromirror elements in the DMD does not prevent full reconstruction of the images. This brings additional robustness to the proposed 3D imaging LIDAR. The prototype that was implemented has three modes of operation. Range Finder: outputs the average distance between the system and the area of the target under illumination; Attitude Meter: provides the slope of the target surface based on distance measurements in three areas of the target; 3D Imager: produces 3D ranged

Real-time data acquisition and control system for the 349-pixel TACTIC atmospheric Cherenkov imaging telescope

Energy Technology Data Exchange (ETDEWEB)

Yadav, K.K.; Koul, R.; Kanda, A.; Kaul, S.R.; Tickoo, A.K. E-mail: aktickoo@apsara.barc.ernet.in; Rannot, R.C.; Chandra, P.; Bhatt, N.; Chouhan, N.; Venugopal, K.; Kothari, M.; Goyal, H.C.; Dhar, V.K.; Kaul, S.K

2004-07-21

An interrupt-based multinode data acquisition and control system has been developed for the imaging element of the TACTIC {gamma}-ray telescope. The system which has been designed around a 3-node network of PCs running the QNX real-time operating system, provides single-point control with elaborate GUI facilities for operating the multi-pixel camera of the telescope. In addition to acquiring data from the 349-pixel photomultiplier tube based imaging camera in real time, the system also provides continuous monitoring and control of several vital parameters of the telescope for ensuring the quality of the data. The paper describes the salient features of the hardware and software of the data acquisition and control system of the telescope.

CVD diamond pixel detectors for LHC experiments

Energy Technology Data Exchange (ETDEWEB)

Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N

1999-08-01

This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described.

CVD diamond pixel detectors for LHC experiments

International Nuclear Information System (INIS)

Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N.

1999-01-01

This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described

OMI/Aura Zoom-in Ground Pixel Corners 1-Orbit L2 Swath 13x12km V003 (OMPIXCORZ) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The Version-3 Aura Ozone Monitoring Instrument (OMI) Pixel Corner Product in zoom-in mode, OMPIXCORZ, is now available from the NASA Goddard Earth Sciences Data and...

Urban Image Classification: Per-Pixel Classifiers, Sub-Pixel Analysis, Object-Based Image Analysis, and Geospatial Methods. 10; Chapter

Science.gov (United States)

Myint, Soe W.; Mesev, Victor; Quattrochi, Dale; Wentz, Elizabeth A.

2013-01-01

Remote sensing methods used to generate base maps to analyze the urban environment rely predominantly on digital sensor data from space-borne platforms. This is due in part from new sources of high spatial resolution data covering the globe, a variety of multispectral and multitemporal sources, sophisticated statistical and geospatial methods, and compatibility with GIS data sources and methods. The goal of this chapter is to review the four groups of classification methods for digital sensor data from space-borne platforms; per-pixel, sub-pixel, object-based (spatial-based), and geospatial methods. Per-pixel methods are widely used methods that classify pixels into distinct categories based solely on the spectral and ancillary information within that pixel. They are used for simple calculations of environmental indices (e.g., NDVI) to sophisticated expert systems to assign urban land covers. Researchers recognize however, that even with the smallest pixel size the spectral information within a pixel is really a combination of multiple urban surfaces. Sub-pixel classification methods therefore aim to statistically quantify the mixture of surfaces to improve overall classification accuracy. While within pixel variations exist, there is also significant evidence that groups of nearby pixels have similar spectral information and therefore belong to the same classification category. Object-oriented methods have emerged that group pixels prior to classification based on spectral similarity and spatial proximity. Classification accuracy using object-based methods show significant success and promise for numerous urban 3 applications. Like the object-oriented methods that recognize the importance of spatial proximity, geospatial methods for urban mapping also utilize neighboring pixels in the classification process. The primary difference though is that geostatistical methods (e.g., spatial autocorrelation methods) are utilized during both the pre- and post

Generalized coupling resonance modeling, analysis, and active damping of multi-parallel inverters in microgrid operating in grid-connected mode

DEFF Research Database (Denmark)

Chen, Zhiyong; Chen, Yandong; Guerrero, Josep M.

2016-01-01

This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic...

CVD diamond pixel detectors for LHC experiments

CERN Document Server

Wedenig, R; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Runólfsson, O; Russ, J; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Trawick, M L; Trischuk, W; Vittone, E; Wagner, A; Walsh, A M; Weilhammer, Peter; White, C; Zeuner, W; Ziock, H J; Zöller, M

1999-01-01

This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described. (9 refs).

Mapping Electrical Crosstalk in Pixelated Sensor Arrays

Science.gov (United States)

Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M. (Inventor); Hancock, Bruce R. (Inventor)

2017-01-01

The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Djama, Fares; The ATLAS collaboration

2017-01-01

Run 2 of the LHC collider sets new challenges to track and vertex reconstruction because of its higher energy, pileup and luminosity. The ATLAS tracking performance relies critically on the Pixel Detector. Therefore, in view of Run 2, the ATLAS collaboration has constructed the first 4-layer pixel detector in Particle Physics by installing a new pixel layer, called Insertable B-Layer (IBL). Operational experience and performance of the 4-layer Pixel Detector during Run 2 are presented.

Development of a cylindrical tracking detector with multichannel scintillation fibers and pixelated photon detector readout

Energy Technology Data Exchange (ETDEWEB)

Akazawa, Y.; Miwa, K.; Honda, R.; Shiozaki, T.; Chiga, N.

2015-07-01

We are developing a cylindrical tracking detector for a Σp scattering experiment in J-PARC with scintillation fibers and the Pixelated Photon Detector (PPD) readout, which is called as cylindrical fiber tracker (CFT), in order to reconstruct trajectories of charged particles emitted inside CFT. CFT works not only as a tracking detector but also a particle identification detector from energy deposits. A prototype CFT consisting of two straight layers and one spiral layer was constructed. About 1100 scintillation fibers with a diameter of 0.75 mm (Kuraray SCSF-78 M) were used. Each fiber signal was read by Multi-Pixel Photon Counter (MPPC, HPK S10362-11-050P, 1×1 mm{sup 2}, 400 pixels) fiber by fiber. MPPCs were handled with Extended Analogue Silicon Photomultipliers Integrated ReadOut Chip (EASIROC) boards, which were developed for the readout of a large number of MPPCs. The energy resolution of one layer was 28% for a 70 MeV proton where the energy deposit in fibers was 0.7 MeV.

Adhesion force imaging in air and liquid by adhesion mode atomic force microscopy

NARCIS (Netherlands)

van der Werf, Kees; Putman, C.A.J.; Putman, Constant A.; de Grooth, B.G.; Greve, Jan

1994-01-01

A new imaging mode for the atomic force microscope(AFM), yielding images mapping the adhesion force between tip and sample, is introduced. The adhesion mode AFM takes a force curve at each pixel by ramping a piezoactuator, moving the silicon‐nitride tip up and down towards the sample. During the

A contextual classifier that only requires one prototype pixel for each class

DEFF Research Database (Denmark)

Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær; Conradsen, Knut

2001-01-01

constructed with experimental data is used in this stage. The algorithm was tested with the Kappa coefficient k on synthetical images and compared with K-means (k~=0.41) and a similar scheme that uses spectral means (k~=0.75) instead of histograms (k~=0.90). Results are shown on a dermatological image......A three stage scheme for classification of multi-spectral images is proposed. In each stage, statistics of each class present in the image are estimated. The user is required to provide only one prototype pixel for each class to be seeded into a homogeneous region. The algorithm starts...... by generating optimum initial training sets, one for each class, maximizing the redundancy in the data sets. These sets are the realizations of the maximal discs centered on the prototype pixels for which it is true that all the elements belong to the same class as the center one. Afterwards a region growing...

EXCALIBUR: a small-pixel photon counting area detector for coherent X-ray diffraction - Front-end design, fabrication and characterisation

Science.gov (United States)

Marchal, J.; Horswell, I.; Willis, B.; Plackett, R.; Gimenez, E. N.; Spiers, J.; Ballard, D.; Booker, P.; Thompson, J. A.; Gibbons, P.; Burge, S. R.; Nicholls, T.; Lipp, J.; Tartoni, N.

2013-03-01

Coherent X-ray diffraction experiments on synchrotron X-ray beamlines require detectors with high spatial resolution and large detection area. The read-out chip developed by the MEDIPIX3 collaboration offers a small pixel size of 55 microns resulting in a very high spatial resolution when coupled to a direct X-ray conversion segmented silicon sensor. MEDIPIX3 assemblies present also the advantages of hybrid pixel detectors working in single photon counting mode: noiseless imaging, large dynamic range, extremely high frame rate. The EXCALIBUR detector is under development for the X-ray Coherence and Imaging Beamline I13 of the Diamond Light Source. This new detector consists of three modules, each with 16 MEDIPIX3 chips which can be read-out at 100 frames per second in continuous mode or 1000 frames per second in burst mode. In each module, the sensor is a large single silicon die covering 2 rows of 8 individual MEDIPIX3 read-out chips and provides a continuous active detection region within a module. Each module includes 1 million solder bumps connecting the 55 microns pixels of the silicon sensor to the 55 microns pixels of the 16 MEDIPIX3 read-out chips. The detection area of the 3-module EXCALIBUR detector is 115 mm × 100 mm with a small 6.8 mm wide inactive region between modules. Each detector module is connected to 2 FPGA read-out boards via a flexi-rigid circuit to allow a fully parallel read-out of the 16 MEDIPIX3 chips. The 6 FPGA read-out boards used in the EXCALIBUR detector are interfaced to 6 computing nodes via 10Gbit/s fibre-optic links to maintain the very high frame-rate capability. The standard suite of EPICS control software is used to operate the detector and to integrate it with the Diamond Light Source beamline software environment. This article describes the design, fabrication and characterisation of the MEDIPIX3-based modules composing the EXCALIBUR detector.

EXCALIBUR: a small-pixel photon counting area detector for coherent X-ray diffraction - Front-end design, fabrication and characterisation

International Nuclear Information System (INIS)

Marchal, J; Horswell, I; Willis, B; Plackett, R; Gimenez, E N; Spiers, J; Thompson, J A; Gibbons, P; Tartoni, N; Ballard, D; Booker, P; Burge, S R; Nicholls, T; Lipp, J

2013-01-01

Coherent X-ray diffraction experiments on synchrotron X-ray beamlines require detectors with high spatial resolution and large detection area. The read-out chip developed by the MEDIPIX3 collaboration offers a small pixel size of 55 microns resulting in a very high spatial resolution when coupled to a direct X-ray conversion segmented silicon sensor. MEDIPIX3 assemblies present also the advantages of hybrid pixel detectors working in single photon counting mode: noiseless imaging, large dynamic range, extremely high frame rate. The EXCALIBUR detector is under development for the X-ray Coherence and Imaging Beamline I13 of the Diamond Light Source. This new detector consists of three modules, each with 16 MEDIPIX3 chips which can be read-out at 100 frames per second in continuous mode or 1000 frames per second in burst mode. In each module, the sensor is a large single silicon die covering 2 rows of 8 individual MEDIPIX3 read-out chips and provides a continuous active detection region within a module. Each module includes 1 million solder bumps connecting the 55 microns pixels of the silicon sensor to the 55 microns pixels of the 16 MEDIPIX3 read-out chips. The detection area of the 3-module EXCALIBUR detector is 115 mm × 100 mm with a small 6.8 mm wide inactive region between modules. Each detector module is connected to 2 FPGA read-out boards via a flexi-rigid circuit to allow a fully parallel read-out of the 16 MEDIPIX3 chips. The 6 FPGA read-out boards used in the EXCALIBUR detector are interfaced to 6 computing nodes via 10Gbit/s fibre-optic links to maintain the very high frame-rate capability. The standard suite of EPICS control software is used to operate the detector and to integrate it with the Diamond Light Source beamline software environment. This article describes the design, fabrication and characterisation of the MEDIPIX3-based modules composing the EXCALIBUR detector.

Intelligent wear mode identification system for marine diesel engines based on multi-level belief rule base methodology

Science.gov (United States)

Yan, Xinping; Xu, Xiaojian; Sheng, Chenxing; Yuan, Chengqing; Li, Zhixiong

2018-01-01

Wear faults are among the chief causes of main-engine damage, significantly influencing the secure and economical operation of ships. It is difficult for engineers to utilize multi-source information to identify wear modes, so an intelligent wear mode identification model needs to be developed to assist engineers in diagnosing wear faults in diesel engines. For this purpose, a multi-level belief rule base (BBRB) system is proposed in this paper. The BBRB system consists of two-level belief rule bases, and the 2D and 3D characteristics of wear particles are used as antecedent attributes on each level. Quantitative and qualitative wear information with uncertainties can be processed simultaneously by the BBRB system. In order to enhance the efficiency of the BBRB, the silhouette value is adopted to determine referential points and the fuzzy c-means clustering algorithm is used to transform input wear information into belief degrees. In addition, the initial parameters of the BBRB system are constructed on the basis of expert-domain knowledge and then optimized by the genetic algorithm to ensure the robustness of the system. To verify the validity of the BBRB system, experimental data acquired from real-world diesel engines are analyzed. Five-fold cross-validation is conducted on the experimental data and the BBRB is compared with the other four models in the cross-validation. In addition, a verification dataset containing different wear particles is used to highlight the effectiveness of the BBRB system in wear mode identification. The verification results demonstrate that the proposed BBRB is effective and efficient for wear mode identification with better performance and stability than competing systems.

Design of a Multi-mode Flight Deck Decision Support System for Airborne Conflict Management

Science.gov (United States)

Barhydt, Richard; Krishnamurthy, Karthik

2004-01-01

NASA Langley has developed a multi-mode decision support system for pilots operating in a Distributed Air-Ground Traffic Management (DAG-TM) environment. An Autonomous Operations Planner (AOP) assists pilots in performing separation assurance functions, including conflict detection, prevention, and resolution. Ongoing AOP design has been based on a comprehensive human factors analysis and evaluation results from previous human-in-the-loop experiments with airline pilot test subjects. AOP considers complex flight mode interactions and provides flight guidance to pilots consistent with the current aircraft control state. Pilots communicate goals to AOP by setting system preferences and actively probing potential trajectories for conflicts. To minimize training requirements and improve operational use, AOP design leverages existing alerting philosophies, displays, and crew interfaces common on commercial aircraft. Future work will consider trajectory prediction uncertainties, integration with the TCAS collision avoidance system, and will incorporate enhancements based on an upcoming air-ground coordination experiment.

Fully 3-D list-mode positron emission tomography image reconstruction on a multi-GPU cluster

Energy Technology Data Exchange (ETDEWEB)

Cui, Jingyu [Stanford Univ., CA (United States). Dept. of Electrical Engineering; Prevrhal, Sven; Shao, Lingxiong [Philips Healthcare, San Jose, CA (United States); Pratx, Guillem [Stanford Univ., CA (United States). Dept. of Radiation Oncology; Levin, Craig S. [Stanford Univ., CA (United States). Dept. of Radiology, Electrical Engineering, and Physics; Stanford Univ., CA (United States). Molecular Imaging Program at Stanford (MIPS); Stanford Univ., CA (United States). School of Medicine

2011-07-01

List-mode processing is an efficient way of dealing with the sparse nature of PET data sets, and is the processing method of choice for time-of-flight (ToF) PET. We present a novel method of computing line projection operations required for list-mode ordered subsets expectation maximization (OSEM) for fully 3-D PET image reconstruction on a graphics processing unit (GPU) using the compute unified device architecture (CUDA) framework. Our method overcomes challenges such as compute thread divergence, and exploits GPU capabilities such as shared memory and atomic operations. When applied to line projection operations for list-mode time-of-flight PET, this new GPU-CUDA reformulation is 188X faster than a single-threaded reference CPU implementation. When embedded in a multi-process environment on a GPU-equipped small cluster, a speedup of 4X was observed over the same configuration but without GPU support. Image quality is preserved with root mean squared (RMS) deviation of 0.05% between CPU and GPU-generated images, which has negligible effect in typical clinical applications. (orig.)

In-situ stabilization of the Geiger (C and M Oil) Superfund Site

International Nuclear Information System (INIS)

Andromalos, K.B.; Ameel, M.E.

1994-01-01

The Geiger (C and M Oil) Superfund Site is the first US Army Corps of Engineers managed soil remediation project which utilized the in-situ stabilization/solidification technique to remediate the soil. This project involved the remediation of approximately 23,000 cubic yards of contaminated soil. Contaminants of concern included chromium, lead, PCB'S, toluene, benzene, and other organic compounds. Clean-up criteria for the stabilized material was equal to the National Primary Drinking Water Regulations, when tested using the TCLP leachate extraction method. Chromium, lead, and toluene were the main contaminants of concern, with TCLP clean-up goals of 150, 15 and 1,000 parts per billion (ppb), respectively. This National Priorities List (NPL) site is located near Charleston, SC and was an abandoned old waste oil facility that utilized unlined shallow trenches for the storage of waste oil. This paper summarizes the initial testing programs and the final production work at the site. Extensive testing was performed throughout all phases of the project. This testing was performed for the purpose of mix optimization, quality assurance, and verification testing. Specific parameters tested included: TCLP testing of organics, metals and PCBs, permeability testing, and unconfirmed compression strength

Development of a fast multi-line x-ray CT detector for NDT

International Nuclear Information System (INIS)

Hofmann, T.; Nachtrab, F.; Schlechter, T.; Mühlbauer, J.; Schröpfer, S.; Firsching, M.; Uhlmann, N.; Neubauer, H.; Ernst, J.; Schweiger, T.; Oberst, M.; Meyer, A.

2015-01-01

Typical X-ray detectors for non-destructive testing (NDT) are line detectors or area detectors, like e.g. flat panel detectors. Multi-line detectors are currently only available in medical Computed Tomography (CT) scanners. Compared to flat panel detectors, line and multi-line detectors can achieve much higher frame rates. This allows time-resolved 3D CT scans of an object under investigation. Also, an improved image quality can be achieved due to reduced scattered radiation from object and detector themselves. Another benefit of line and multi-line detectors is that very wide detectors can be assembled easily, while flat panel detectors are usually limited to an imaging field with a size of approx. 40 × 40 cm 2 at maximum. The big disadvantage of line detectors is the limited number of object slices that can be scanned simultaneously. This leads to long scan times for large objects. Volume scans with a multi-line detector are much faster, but with almost similar image quality. Due to the promising properties of multi-line detectors their application outside of medical CT would also be very interesting for NDT. However, medical CT multi-line detectors are optimized for the scanning of human bodies. Many non-medical applications require higher spatial resolutions and/or higher X-ray energies. For those non-medical applications we are developing a fast multi-line X-ray detector.In the scope of this work, we present the current state of the development of the novel detector, which includes several outstanding properties like an adjustable curved design for variable focus-detector-distances, conserving nearly uniform perpendicular irradiation over the entire detector width. Basis of the detector is a specifically designed, radiation hard CMOS imaging sensor with a pixel pitch of 200 μ m. Each pixel has an automatic in-pixel gain adjustment, which allows for both: a very high sensitivity and a wide dynamic range. The final detector is planned to have 256 lines of

Developments of the ATLAS pixel detector

International Nuclear Information System (INIS)

Andreazza, Attilio

2004-01-01

The ATLAS silicon pixel detector is the innermost tracking device of the ATLAS experiment at the Large Hardon Collider, consisting of more than 1700 modules for a total sensitive area of about 1.7m2 and over 80 million pixel cells. The concept is a hybrid of front-end chips bump bonded to the pixel sensor. The elementary pixel cell has 50μmx400μm size, providing pulse height information via the time over threshold technique. Prototype devices with oxygenated silicon sensor and rad-hard electronics built in the IBM 0.25μm process have been tested and maintain good resolution, efficiency and timing performances even after receiving the design radiation damage of 1015neq/cm2

Alignment, orientation, and Coulomb explosion of difluoroiodobenzene studied with the pixel imaging mass spectrometry (PImMS) camera.

Science.gov (United States)

Amini, Kasra; Boll, Rebecca; Lauer, Alexandra; Burt, Michael; Lee, Jason W L; Christensen, Lauge; Brauβe, Felix; Mullins, Terence; Savelyev, Evgeny; Ablikim, Utuq; Berrah, Nora; Bomme, Cédric; Düsterer, Stefan; Erk, Benjamin; Höppner, Hauke; Johnsson, Per; Kierspel, Thomas; Krecinic, Faruk; Küpper, Jochen; Müller, Maria; Müller, Erland; Redlin, Harald; Rouzée, Arnaud; Schirmel, Nora; Thøgersen, Jan; Techert, Simone; Toleikis, Sven; Treusch, Rolf; Trippel, Sebastian; Ulmer, Anatoli; Wiese, Joss; Vallance, Claire; Rudenko, Artem; Stapelfeldt, Henrik; Brouard, Mark; Rolles, Daniel

2017-07-07

Laser-induced adiabatic alignment and mixed-field orientation of 2,6-difluoroiodobenzene (C 6 H 3 F 2 I) molecules are probed by Coulomb explosion imaging following either near-infrared strong-field ionization or extreme-ultraviolet multi-photon inner-shell ionization using free-electron laser pulses. The resulting photoelectrons and fragment ions are captured by a double-sided velocity map imaging spectrometer and projected onto two position-sensitive detectors. The ion side of the spectrometer is equipped with a pixel imaging mass spectrometry camera, a time-stamping pixelated detector that can record the hit positions and arrival times of up to four ions per pixel per acquisition cycle. Thus, the time-of-flight trace and ion momentum distributions for all fragments can be recorded simultaneously. We show that we can obtain a high degree of one-and three-dimensional alignment and mixed-field orientation and compare the Coulomb explosion process induced at both wavelengths.

The ALPIDE pixel sensor chip for the upgrade of the ALICE Inner Tracking System

CERN Document Server

Aglieri Rinella, Gianluca

2017-01-01

The ALPIDE chip is a CMOS Monolithic Active Pixel Sensor being developed for the Upgrade of the ITS of the ALICE experiment at the CERN Large Hadron Collider. The ALPIDE chip is implemented with a 180 nm CMOS Imaging Process and fabricated on substrates with a high-resistivity epitaxial layer. It measures 15 mm×30 mm and contains a matrix of 512×1024 pixels with in-pixel amplification, shaping, discrimination and multi-event buffering. The readout of the sensitive matrix is hit driven. There is no signaling activity over the matrix if there are no hits to read out and power consumption is proportional to the occupancy. The sensor meets the experimental requirements of detection efficiency above 99%, fake-hit probability below 10−5 and a spatial resolution of 5 μm. The capability to read out Pb–Pb interactions at 100 kHz is provided. The power density of the ALPIDE chip is projected to be less than 35 mW/cm2 for the application in the Inner Barrel Layers and below 20 mW/cm2 for the Outer Barrel Layers, ...

The DELPHI pixels

International Nuclear Information System (INIS)

Becks, K.H.; Brunet, J.M.

1997-01-01

To improve tracking in the very forward direction for running at LEP200, the angular acceptance of the DELPHI Vertex detector has been extended from 45 to 11 with respect to the beam axis. Pixel detector crowns cover the region between 25 and 13 . Due to very tight space and material thickness constraints it was necessary to develop new techniques (integrated busses in the detector substrate, high density layout on Kapton, etc.). About 1000 cm 2 of pixels are already installed and working in DELPHI. Techniques, tests and production of these detectors will be described, as well as the main problems encountered during this work. (orig.)

Superconducting multi-cell trapped mode deflecting cavity

Science.gov (United States)

Lunin, Andrei; Khabiboulline, Timergali; Gonin, Ivan; Yakovlev, Vyacheslav; Zholents, Alexander

2017-10-10

A method and system for beam deflection. The method and system for beam deflection comprises a compact superconducting RF cavity further comprising a waveguide comprising an open ended resonator volume configured to operate as a trapped dipole mode; a plurality of cells configured to provide a high operating gradient; at least two pairs of protrusions configured for lowering surface electric and magnetic fields; and a main power coupler positioned to optimize necessary coupling for an operating mode and damping lower dipole modes simultaneously.

Multi-mode optical fibers for connecting space-based spectrometers

Science.gov (United States)

Roberts, W. T.; Lindenmisth, C. A.; Bender, S.; Miller, E. A.; Motts, E.; Ott, M.; LaRocca, F.; Thomes, J.

2017-11-01

significantly smaller, less massive and less robust. Large core multi-mode optical fibers are often used to accommodate the optical connection of the two separated portions of such instrumentation. In some cases, significant throughput efficiency improvement can be realized by judiciously orienting the strands of multi-fiber cable, close-bunching them to accommodate a tight focus of the optical system on the optical side of the connection, and splaying them out linearly along a spectrometer slit on the other end. For such instrumentation to work effectively in identifying elements and molecules, and especially to produce accurate quantitative results, the spectral throughput of the optical fiber connection must be consistent over varying temperatures, over the range of motion of the optical head (and it's implied optical cable stresses), and over angle-aperture invariant of the total system. While the first two of these conditions have been demonstrated[4], spectral observations of the latter present a cause for concern, and may have an impact on future design of fiber-connected LIBS and Raman spectroscopy instruments. In short, we have observed that the shape of the spectral efficiency curve of a large multi-mode core optical fiber changes as a function of input angle.

Retrieval of Cloud Properties for Partially Cloud-Filled Pixels During CRYSTAL-FACE

Science.gov (United States)

Nguyen, L.; Minnis, P.; Smith, W. L.; Khaiyer, M. M.; Heck, P. W.; Sun-Mack, S.; Uttal, T.; Comstock, J.

2003-12-01

Partially cloud-filled pixels can be a significant problem for remote sensing of cloud properties. Generally, the optical depth and effective particle sizes are often too small or too large, respectively, when derived from radiances that are assumed to be overcast but contain radiation from both clear and cloud areas within the satellite imager field of view. This study presents a method for reducing the impact of such partially cloud field pixels by estimating the cloud fraction within each pixel using higher resolution visible (VIS, 0.65mm) imager data. Although the nominal resolution for most channels on the Geostationary Operational Environmental Satellite (GOES) imager and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra are 4 and 1 km, respectively, both instruments also take VIS channel data at 1 km and 0.25 km, respectively. Thus, it may be possible to obtain an improved estimate of cloud fraction within the lower resolution pixels by using the information contained in the higher resolution VIS data. GOES and MODIS multi-spectral data, taken during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE), are analyzed with the algorithm used for the Atmospheric Radiation Measurement Program (ARM) and the Clouds and Earth's Radiant Energy System (CERES) to derive cloud amount, temperature, height, phase, effective particle size, optical depth, and water path. Normally, the algorithm assumes that each pixel is either entirely clear or cloudy. In this study, a threshold method is applied to the higher resolution VIS data to estimate the partial cloud fraction within each low-resolution pixel. The cloud properties are then derived from the observed low-resolution radiances using the cloud cover estimate to properly extract the radiances due only to the cloudy part of the scene. This approach is applied to both GOES and MODIS data to estimate the improvement in the retrievals for each

Noise analysis of a novel hybrid active-passive pixel sensor for medical X-ray imaging

International Nuclear Information System (INIS)

Safavian, N.; Izadi, M.H.; Sultana, A.; Wu, D.; Karim, K.S.; Nathan, A.; Rowlands, J.A.

2009-01-01

Passive pixel sensor (PPS) is one of the most widely used architectures in large area amorphous silicon (a-Si) flat panel imagers. It consists of a detector and a thin film transistor (TFT) acting as a readout switch. While the PPS is advantageous in terms of providing a simple and small architecture suitable for high-resolution imaging, it directly exposes the signal to the noise of data line and external readout electronics, causing significant increase in the minimum readable sensor input signal. In this work we present the operation and noise performance of a hybrid 3-TFT current programmed, current output active pixel sensor (APS) suitable for real-time X-ray imaging. The pixel circuit extends the application of a-Si TFT from conventional switching element to on-pixel amplifier for enhanced signal-to-noise ratio and higher imager dynamic range. The capability of operation in both passive and active modes as well as being able to compensate for inherent instabilities of the TFTs makes the architecture a good candidate for X-ray imaging modalities with a wide range of incoming X-ray intensities. Measurement and theoretical calculations reveal a value for input refferd noise below the 1000 electron noise limit for real-time fluoroscopy. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Calculating Viewing Angles Pixel by Pixel in Optical Remote Sensing Satellite Imagery Using the Rational Function Model

OpenAIRE

Kai Xu; Guo Zhang; Qingjun Zhang; Deren Li

2018-01-01

In studies involving the extraction of surface physical parameters using optical remote sensing satellite imagery, sun-sensor geometry must be known, especially for sensor viewing angles. However, while pixel-by-pixel acquisitions of sensor viewing angles are of critical importance to many studies, currently available algorithms for calculating sensor-viewing angles focus only on the center-point pixel or are complicated and are not well known. Thus, this study aims to provide a simple and ge...

The multi-mode modulator: A versatile fluidic device for two-dimensional gas chromatography.

Science.gov (United States)

Seeley, John V; Schimmel, Nicolaas E; Seeley, Stacy K

2018-02-09

A fluidic device called the multi-mode modulator (MMM) has been developed for use as a comprehensive two-dimensional gas chromatography (GC x GC) modulator. The MMM can be employed in a wide range of capacities including as a traditional heart-cutting device, a low duty cycle GC x GC modulator, and a full transfer GC x GC modulator. The MMM is capable of producing narrow component pulses (widths <50ms) while operating at flows compatible with high resolution chromatography. The sample path of modulated components is confined to the interior of a joining capillary. The joining capillary dimensions and the position of the columns within the joining capillary can be optimized for the selected modulation mode. Furthermore, the joining capillary can be replaced easily and inexpensively if it becomes fouled due to sample matrix components or column bleed. The principles of operation of the MMM are described and its efficacy is demonstrated as a heart-cutting device and as a GC x GC modulator. Copyright © 2017 Elsevier B.V. All rights reserved.

FACT. New image parameters based on the watershed-algorithm

Energy Technology Data Exchange (ETDEWEB)

Linhoff, Lena; Bruegge, Kai Arno; Buss, Jens [TU Dortmund (Germany). Experimentelle Physik 5b; Collaboration: FACT-Collaboration

2016-07-01

FACT, the First G-APD Cherenkov Telescope, is the first imaging atmospheric Cherenkov telescope that is using Geiger-mode avalanche photodiodes (G-APDs) as photo sensors. The raw data produced by this telescope are processed in an analysis chain, which leads to a classification of the primary particle that induce a shower and to an estimation of its energy. One important step in this analysis chain is the parameter extraction from shower images. By the application of a watershed algorithm to the camera image, new parameters are computed. Perceiving the brightness of a pixel as height, a set of pixels can be seen as 'landscape' with hills and valleys. A watershed algorithm groups all pixels to a cluster that belongs to the same hill. From the emerging segmented image, one can find new parameters for later analysis steps, e.g. number of clusters, their shape and containing photon charge. For FACT data, the FellWalker algorithm was chosen from the class of watershed algorithms, because it was designed to work on discrete distributions, in this case the pixels of a camera image. The FellWalker algorithm is implemented in FACT-tools, which provides the low level analysis framework for FACT. This talk will focus on the computation of new, FellWalker based, image parameters, which can be used for the gamma-hadron separation. Additionally, their distributions concerning real and Monte Carlo Data are compared.

Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

Science.gov (United States)

Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

2015-03-01

Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

Applying Statistical Mechanics to pixel detectors

International Nuclear Information System (INIS)

Pindo, Massimiliano

2002-01-01

Pixel detectors, being made of a large number of active cells of the same kind, can be considered as significant sets to which Statistical Mechanics variables and methods can be applied. By properly redefining well known statistical parameters in order to let them match the ones that actually characterize pixel detectors, an analysis of the way they work can be performed in a totally new perspective. A deeper understanding of pixel detectors is attained, helping in the evaluation and comparison of their intrinsic characteristics and performance

Field-portable pixel super-resolution colour microscope.

Directory of Open Access Journals (Sweden)

Alon Greenbaum

Full Text Available Based on partially-coherent digital in-line holography, we report a field-portable microscope that can render lensfree colour images over a wide field-of-view of e.g., >20 mm(2. This computational holographic microscope weighs less than 145 grams with dimensions smaller than 17×6×5 cm, making it especially suitable for field settings and point-of-care use. In this lensfree imaging design, we merged a colorization algorithm with a source shifting based multi-height pixel super-resolution technique to mitigate 'rainbow' like colour artefacts that are typical in holographic imaging. This image processing scheme is based on transforming the colour components of an RGB image into YUV colour space, which separates colour information from brightness component of an image. The resolution of our super-resolution colour microscope was characterized using a USAF test chart to confirm sub-micron spatial resolution, even for reconstructions that employ multi-height phase recovery to handle dense and connected objects. To further demonstrate the performance of this colour microscope Papanicolaou (Pap smears were also successfully imaged. This field-portable and wide-field computational colour microscope could be useful for tele-medicine applications in resource poor settings.

Performance evaluation of SiPM photodetectors for PET imaging in the presence of magnetic fields

Energy Technology Data Exchange (ETDEWEB)

Espana, S., E-mail: samuel@nuclear.fis.ucm.e [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Fraile, L.M.; Herraiz, J.L.; Udias, J.M. [Grupo de Fisica Nuclear, Dpto. Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Desco, M.; Vaquero, J.J. [Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain)

2010-02-01

The multi-pixel photon counter (MPPC) or silicon photomultiplier (SiPM), recently introduced as a solid-state photodetector, consists of an array of Geiger-mode photodiodes (microcells). It is a promising device for PET due to its potential for high photon detection efficiency (PDE) and its foreseeable immunity to magnetic fields. It is also easy to use with simple read-outs, has a high gain and a small size. In this work we evaluate the in field performance of three 1x1 mm{sup 2} (with 100, 400 and 1600 microcells, respectively) and one 6x6 mm{sup 2} (arranged as a 2x2 array) Hamamatsu MPPCs for their use in PET imaging. We examine the dependence of the energy resolution and the gain of these devices on the temperature and reverse bias voltage, when coupled to LYSO scintillator crystals under conditions that one would find in a PET system. We find that the 400 and 1600 microcells models and the 2x2 array are suitable for small-size crystals, like those employed in high resolution small animal scanners. We have confirmed the good performance of these devices up to magnetic fields of 7 T as well as their suitability for performing PET acquisitions in the presence of fast switching gradients and high duty radiofrequency MRI sequences.

Parameters of the preproduction series SiPMs for the CMS HCAL phase I upgrade

Energy Technology Data Exchange (ETDEWEB)

Heering, A., E-mail: Adriaan.Heering@cern.ch [University of Notre Dame, Notre Dame, IN 46556 (United States); Musienko, Yu., E-mail: Iouri.Musienko@cern.ch [University of Notre Dame, Notre Dame, IN 46556 (United States); Institute for Nuclear Research RAS, pr. 60-letiya Oktyabrya 7a, 117312 Moscow (Russian Federation); Ruchti, R.; Wayne, M. [University of Notre Dame, Notre Dame, IN 46556 (United States); Karneyeu, A.; Postoev, V. [Institute for Nuclear Research RAS, pr. 60-letiya Oktyabrya 7a, 117312 Moscow (Russian Federation)

2016-07-11

In 2012 the HCAL SiPM photo sensor upgrade was approved for the increased luminosity (5*10{sup 34}) of SLHC. The upgrade will replace the current hybrid photodiodes (HPDs) with multi-pixel Geiger-mode avalanche photodiodes, also known as silicon photomultipliers (SiPMs). A key aspect of the upgrade to SiPMs is to add longitudinal segmentation and improve signal to noise to compensate for scintillator radiation damage. After 5 years of R&D with multiple companies we developed custom large dynamic range SiPMs with large PDE and small ENC. To ensure good mechanical alignment and easy handling of the large number of production channels (>20,000) we have developed a custom ceramic package with a very thin 0.3 mm quartz window with Kyocera. Each package holds 8 channels of SiPMs. Here we report on the final SiPM parameters of the 2014 preproduction run from Hamamatsu (HPK) who has produced a series of 175 arrays with a total of 1400 SiPMs. An overview of our QA results and measurements of the photon detection efficiency, spectral response, crosstalk and cell recovery time will be discussed. - Highlights: • Uniformity of large scale SiPM production. • Small cell size SiPMs with high photo detection efficiency. • Fast recovery time SiPMs. • Custom packaging of SiPMs in High Energy Physics experiments.

Pixelated CdZnTe drift detectors

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl

2005-01-01

A technique, the so-called Drift Strip Method (DSM), for improving the CdZnTe detector energy response to hard X-rays and gamma-rays was applied as a pixel geometry. First tests have confirmed that this detector type provides excellent energy resolution and imaging performance. We specifically...... report on the performance of 3 mm thick prototype CZT drift pixel detectors fabricated using material from eV-products. We discuss issues associated with detector module performance. Characterization results obtained from several prototype drift pixel detectors are presented. Results of position...

ISPA (imaging silicon pixel array) experiment

CERN Multimedia

Patrice Loïez

2002-01-01

The bump-bonded silicon pixel detector, developed at CERN by the EP-MIC group, is shown here in its ceramic carrier. Both represent the ISPA-tube anode. The chip features between 1024 (called OMEGA-1) and 8196 (ALICE-1) active pixels.

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Djama, Fares; The ATLAS collaboration

2017-01-01

Run-2 of the LHC is providing new challenges to track and vertex reconstruction imposed by the higher collision energy, pileup and luminosity that are being delivered. The ATLAS tracking performance relies critically on the Pixel Detector, therefore, in view of Run-2 of LHC, the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). Pixel detector was refurbished with a new service quarter panel to recover about 3% of defective modules lost during run-1 and an additional optical link per module was added to overcome in some layers the readout bandwidth limitation when LHC will exceed the nominal peak luminosity by almost a factor of 3. The key features and challenges met during the IBL project will be presented, as well as its operational experience and Pixel Detector performance in LHC.

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Lantzsch, Kerstin; The ATLAS collaboration

2016-01-01

Run 2 of the LHC is providing new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. Therefore the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). In addition the Pixel detector was refurbished with new service quarter panels to recover about 3% of defective modules lost during run 1 and a new optical readout system to readout the data at higher speed while reducing the occupancy when running with increased luminosity. The commissioning, operation and performance of the 4-layer Pixel Detector will be presented.

Absorption Mode FT-ICR Mass Spectrometry Imaging

Energy Technology Data Exchange (ETDEWEB)

Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O' Connor, Peter B.; Heeren, Ronald M.

2013-12-03

Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

Focal plane array with modular pixel array components for scalability

Science.gov (United States)

Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

2014-12-09

A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

Coupled Retrieval of Aerosol Properties and Surface Reflection Using the Airborne Multi-angle SpectroPolarimetric Imager (AirMSPI)

Science.gov (United States)

Xu, F.; van Harten, G.; Kalashnikova, O. V.; Diner, D. J.; Seidel, F. C.; Garay, M. J.; Dubovik, O.

2016-12-01

The Airborne Multi-angle SpectroPolarimetric Imager (AirMSPI) [1] has been flying aboard the NASA ER-2 high altitude aircraft since October 2010. In step-and-stare operation mode, AirMSPI acquires radiance and polarization data at 355, 380, 445, 470*, 555, 660*, 865*, and 935 nm (* denotes polarimetric bands). The imaged area covers about 10 km by 10 km and is observed from 9 view angles between ±67° off of nadir. We have developed an efficient and flexible code that uses the information content of AirMSPI data for a coupled retrieval of aerosol properties and surface reflection. The retrieval was built based on the multi-pixel optimization concept [2], with the use of a hybrid radiative transfer model [3] that combines the Markov Chain [4] and adding/doubling methods [5]. The convergence and robustness of our algorithm is ensured by applying constraints on (a) the spectral variation of the Bidirectional Polarization Distribution Function (BPDF) and angular shape of the Bidirectional Reflectance Distribution Function (BRDF); (b) the spectral variation of aerosol optical properties; and (c) the spatial variation of aerosol parameters across neighboring image pixels. Our retrieval approach has been tested using over 20 AirMSPI datasets having low to moderately high aerosol loadings ( 0.02550-nmSpace Sci. Rev. 16, 527 (1974).

Development of pixel detectors for SSC vertex tracking

International Nuclear Information System (INIS)

Kramer, G.; Shapiro, S.L.; Arens, J.F.; Jernigan, J.G.; Skubic, P.

1991-04-01

A description of hybrid PIN diode arrays and a readout architecture for their use as a vertex detector in the SSC environment is presented. Test results obtained with arrays having 256 x 256 pixels, each 30 μm square, are also presented. The development of a custom readout for the SSC will be discussed, which supports a mechanism for time stamping hit pixels, storing their xy coordinates, and storing the analog information within the pixel. The peripheral logic located on the array, permits the selection of those pixels containing interesting data and their coordinates to be selectively read out. This same logic also resolves ambiguous pixel ghost locations and controls the pixel neighbor read out necessary to achieve high spatial resolution. The thermal design of the vertex tracker and the proposed signal processing architecture will also be discussed. 5 refs., 13 figs., 3 tabs

E-Beam Effects on CMOS Active Pixel Sensors

International Nuclear Information System (INIS)

Kang, Dong Ook; Jo, Gyu Seong; Kim, Hyeon Daek; Kim, Hyunk Taek; Kim, Jong Yeol; Kim, Chan Kyu

2011-01-01

Three different CMOS active pixel structures manufactured in a deep submicron process have been evaluated with electron beam. The devices were exposed to 1 MeV electron beam up to 5kGy. Dark current increased after E-beam irradiation differently at each pixel structure. Dark current change is dependent on CMOS pixel structures. CMOS image sensors are now good candidates in demanding applications such as medical image sensor, particle detection and space remote sensing. In these situations, CISs are exposed to high doses of radiation. In fact radiation is known to generate trapped charge in CMOS oxides. It can lead to threshold voltage shifts and current leakages in MOSFETs and dark current increase in photodiodes. We studied ionizing effects in three types of CMOS APSs fabricated by 0.25 CMOS process. The devices were irradiated by a Co 60 source up to 50kGy. All irradiation took place at room temperature. The dark current in the three different pixels exhibits increase with electron beam exposure. From the above figure, the change of dark current is dependent on the pixel structure. Double junction structure has shown relatively small increase of dark current after electron beam irradiation. The dark current in the three different pixels exhibits increase with electron beam exposure. The contribution of the total ionizing dose to the dark current increase is small here, since the devices were left unbiased during the electron beam irradiation. Radiation hardness in dependent on the pixel structures. Pixel2 is relatively vulnerable to radiation exposure. Pixel3 has radiation hardened structure

Operational experience with the ATLAS Pixel Detector

CERN Document Server

Ince, T; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost element of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience of the ATLAS Pixel detector

CERN Document Server

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience of the ATLAS Pixel Detector

CERN Document Server

Marcisovsky, M; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Building CMS Pixel Barrel Detectur Modules

CERN Document Server

König, S; Horisberger, R.; Meier, B.; Rohe, T.; Streuli, S.; Weber, R.; Kastli, H.Chr.; Erdmann, W.

2007-01-01

For the barrel part of the CMS pixel tracker about 800 silicon pixel detector modules are required. The modules are bump bonded, assembled and tested at the Paul Scherrer Institute. This article describes the experience acquired during the assembly of the first ~200 modules.

PIXEL PATTERN BASED STEGANOGRAPHY ON IMAGES

Directory of Open Access Journals (Sweden)

R. Rejani

2015-02-01

Full Text Available One of the drawback of most of the existing steganography methods is that it alters the bits used for storing color information. Some of the examples include LSB or MSB based steganography. There are also various existing methods like Dynamic RGB Intensity Based Steganography Scheme, Secure RGB Image Steganography from Pixel Indicator to Triple Algorithm etc that can be used to find out the steganography method used and break it. Another drawback of the existing methods is that it adds noise to the image which makes the image look dull or grainy making it suspicious for a person about existence of a hidden message within the image. To overcome these shortcomings we have come up with a pixel pattern based steganography which involved hiding the message within in image by using the existing RGB values whenever possible at pixel level or with minimum changes. Along with the image a key will also be used to decrypt the message stored at pixel levels. For further protection, both the message stored as well as the key file will be in encrypted format which can have same or different keys or decryption. Hence we call it as a RGB pixel pattern based steganography.

Design and realization of a fast low noise electronics for a hybrid pixel X-ray detector dedicated to small animal imaging

International Nuclear Information System (INIS)

Chantepie, Benoit

2008-01-01

Since the invention of computerized tomography (CT), charge integration detector were widely employed for X-ray biomedical imaging applications. Nevertheless, other options exist. A new technology of direct detection using semiconductors has been developed for high energy physics instrumentation. This new technology, called hybrid pixel detector, works in photon counting mode and allows for selecting the minimum energy of the counted photons. The imXgam research team at CPPM develops the PIXSCAN demonstrator, a CT-scanner using the hybrid pixel detector XPAD. The aim of this project is to evaluate the improvement on image quality and on dose delivered during X-ray examinations of a small animal. After a first prototype of hybrid pixel detector XPAD1 proving the feasibility of the project, a complete imager XPAD2 was designed and integrated in the PIXSCAN demonstrator. Since then, with the evolution of microelectronic industry, important improvements are conceivable. To reducing the size of pixels and to improving the energy resolution of detectors, a third design XPAD3 was conceived and will be soon integrated in a second generation of PIXSCAN demonstrator. In this project, my thesis's work consisted in taking part to the design of the detector readout electronics, to the characterization of the chips and of the hybrid pixel detectors, and also to the definition of an auto-zeroing architecture for pixels. (author) [fr

A MULTI-SITE CAMPAIGN TO MEASURE SOLAR-LIKE OSCILLATIONS IN PROCYON. II. MODE FREQUENCIES

International Nuclear Information System (INIS)

Bedding, Timothy R.; Bruntt, Hans; Kiss, Laszlo L.; Kjeldsen, Hans; Campante, Tiago L.; Appourchaux, Thierry; Bonanno, Alfio; Chaplin, William J.; Garcia, Rafael A.; Martic, Milena; Mosser, Benoit; Butler, R. Paul; O'Toole, Simon J.; Kambe, Eiji; Izumiura, Hideyuki; Ando, Hiroyasu; Sato, Bun'ei; Hartmann, Michael; Hatzes, Artie

2010-01-01

We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with 11 telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges, which we identify with even and odd values of the angular degree (l = 0 and 2, and l = 1 and 3, respectively). We interpret a strong, narrow peak at 446 μHz that lies close to the l = 1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of ∼1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55 -0.49 days, which is significantly shorter than the 2-4 days seen in the Sun.

Dense SDM (12-core × 3-mode) transmission over 527 km with 33.2-ns mode-dispersion employing low-complexity parallel MIMO frequency-domain equalization

DEFF Research Database (Denmark)

Shibahara, K.; Mizuno, T.; Takara, H.

We demonstrate 12-core × 3-mode dense SDM transmission over 527 km graded-index multi-core few-mode fiber without mode-dispersion management. Employing low baud rate multi-carrier signal and frequency-domain equalization enables 33.2-ns DMD compensation with low computational complexity. © 2015 OSA...

Development and Characterization of Diamond and 3D-Silicon Pixel Detectors with ATLAS-Pixel Readout Electronics

CERN Document Server

Mathes, Markus

2008-01-01

Hybrid pixel detectors are used for particle tracking in the innermost layers of current high energy experiments like ATLAS. After the proposed luminosity upgrade of the LHC, they will have to survive very high radiation fluences of up to 10^16 particles per cm^2 per life time. New sensor concepts and materials are required, which promise to be more radiation tolerant than the currently used planar silicon sensors. Most prominent candidates are so-called 3D-silicon and single crystal or poly-crystalline diamond sensors. Using the ATLAS pixel electronics different detector prototypes with a pixel geometry of 400 × 50 um^2 have been built. In particular three devices have been studied in detail: a 3D-silicon and a single crystal diamond detector with an active area of about 1 cm^2 and a poly-crystalline diamond detector of the same size as a current ATLAS pixel detector module (2 × 6 cm^2). To characterize the devices regarding their particle detection efficiency and spatial resolution, the charge collection ...

Slim edge studies, design and quality control of planar ATLAS IBL pixel sensors

Energy Technology Data Exchange (ETDEWEB)

Wittig, Tobias

2013-05-08

One of the four large experiments at the LHC at CERN is the ATLAS detector, a multi purpose detector. Its pixel detector, composed of three layers, is the innermost part of the tracker. As it is closest to the interaction point, it represents a basic part of the track reconstruction. Besides the requested high resolution one main requirement is the radiation hardness. In the coming years the radiation damage will cause deteriorations of the detector performance. With the planned increase of the luminosity, especially after the upgrade to the High Luminosity LHC, this radiation damage will be even intensified. This circumstance necessitates a new pixel detector featuring improved radiation hard sensors and read-out chips. The present shutdown of the LHC is already utilized to insert an additional b-layer (IBL) into the existing ATLAS pixel detector. The current n-in-n pixel sensor design had to be adapted to the new read-out chip and the module specifications. The new stave geometry requests a reduction of the inactive sensor edge. In a prototype wafer production all modifications have been implemented. The sensor quality control was supervised which led to the decision of the final sensor thickness. In order to evaluate the performance of the sensor chip assemblies with an innovative slim edge design, they have been operated in test beam setups before and after irradiation. Furthermore, the quality control of the planar IBL sensor wafer production was supervised from the stage of wafer delivery to that before the flip chip process to ensure a sufficient amount of functional sensors for the module production.

Method and apparatus for controlling a powertrain system including a multi-mode transmission

Science.gov (United States)

Hessell, Steven M.; Morris, Robert L.; McGrogan, Sean W.; Heap, Anthony H.; Mendoza, Gil J.

2015-09-08

A powertrain including an engine and torque machines is configured to transfer torque through a multi-mode transmission to an output member. A method for controlling the powertrain includes employing a closed-loop speed control system to control torque commands for the torque machines in response to a desired input speed. Upon approaching a power limit of a power storage device transferring power to the torque machines, power limited torque commands are determined for the torque machines in response to the power limit and the closed-loop speed control system is employed to determine an engine torque command in response to the desired input speed and the power limited torque commands for the torque machines.

Temperature-Corrected Oxygen Detection Based on Multi-Mode Diode Laser Correlation Spectroscopy

Directory of Open Access Journals (Sweden)

Xiutao Lou

2013-01-01

Full Text Available Temperature-corrected oxygen measurements were performed by using multi-mode diode laser correlation spectroscopy at temperatures ranging between 300 and 473 K. The experiments simulate in situ monitoring of oxygen in coal-combustion exhaust gases at the tail of the flue. A linear relationship with a correlation coefficient of −0.999 was found between the evaluated concentration and the gas temperature. Temperature effects were either auto-corrected by keeping the reference gas at the same conditions as the sample gas, or rectified by using a predetermined effective temperature-correction coefficient calibrated for a range of absorption wavelengths. Relative standard deviations of the temperature-corrected oxygen concentrations obtained by different schemes and at various temperatures were estimated, yielding a measurement precision of 0.6%.

Design and realization of a fast low noise electronics for a hybrid pixel X-ray detector dedicated to small animal imaging

International Nuclear Information System (INIS)

Chantepie, B.

2008-12-01

Since the invention of computerized tomography (CT), charge integration detector were widely employed for X-ray biomedical imaging applications. Nevertheless, other options exist. A new technology of direct detection using semiconductors has been developed for high energy physics instrumentation. This new technology, called hybrid pixel detector, works in photon counting mode and allows for selecting the minimum energy of the counted photons. The ImXgam research team at CPPM develops the PIXSCAN demonstrator, a CT-scanner using the hybrid pixel detector XPAD. The aim of this project is to evaluate the improvement in image quality and in dose delivered during X-ray examinations of a small animal. After a first prototype of a hybrid pixel detector XPAD1 proving the feasibility of the project, a complete imager XPAD2 was designed and integrated in the PIXSCAN demonstrator. Since then, with the evolution of microelectronic industry, important improvements are conceivable. To reducing the size of pixels and to improving the energy resolution of detectors, a third design XPAD3 was conceived and will be soon integrated in a second generation of PIXSCAN demonstrator. In this project, my thesis work consisted in taking part to the design of the detector readout electronics, to the characterization of the chips and of the hybrid pixel detectors, and also to the definition of a auto-zeroing architecture for pixels. The first and second chapters present X-ray medical imaging and particle detection with semi-conductors and its modelling. The third chapter deals with the specifications of electronic circuits for imaging applications first for analog pixels then for digital pixels and describes the general architecture of the integrated circuits. The validation tests are presented in the fourth chapter while the last chapter gives an account of expected changes in pixel electronics

Multi-frequency modes in superconducting resonators: Bridging frequency gaps in off-resonant couplings

Science.gov (United States)

Andersen, Christian Kraglund; Mølmer, Klaus

2015-03-01

A SQUID inserted in a superconducting waveguide resonator imposes current and voltage boundary conditions that makes it suitable as a tuning element for the resonator modes. If such a SQUID element is subject to a periodically varying magnetic flux, the resonator modes acquire frequency side bands. We calculate the multi-frequency eigenmodes and these can couple resonantly to physical systems with different transition frequencies and this makes the resonator an efficient quantum bus for state transfer and coherent quantum operations in hybrid quantum systems. As an example of the application, we determine their coupling to transmon qubits with different frequencies and we present a bi-chromatic scheme for entanglement and gate operations. In this calculation, we obtain a maximally entangled state with a fidelity F = 95 % . Our proposal is competitive with the achievements of other entanglement-gates with superconducting devices and it may offer some advantages: (i) There is no need for additional control lines and dephasing associated with the conventional frequency tuning of qubits. (ii) When our qubits are idle, they are far detuned with respect to each other and to the resonator, and hence they are immune to cross talk and Purcell-enhanced decay.

Characterization of Pixel Sensors

CERN Document Server

Oliveira, Felipe Ferraz

2017-01-01

It was commissioned at CERN ATLAS pixel group a fluorescence setup for characterization of pixel sensors. The idea is to measure the energies of different targets to calibrate your sensor. It was measured four matrices (80, 95, 98 and 106) of the Investigator1 sensor with different deep PW using copper, iron and titanium as target materials. The matrix 80 has a higher gain (0.065 ± 0.002) and matrix 106 has a better energy resolution (0.05 ± 0.04). The noise of the setup is around 3.6 mV .

LePix—A high resistivity, fully depleted monolithic pixel detector

International Nuclear Information System (INIS)

Giubilato, P.; Bisello, D.; Chalmet, P.; Denes, P.; Kloukinas, K.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Snoeys, W.; Tindall, C.

2013-01-01

The LePix project explores monolithic pixel sensors fabricated in a 90 nm CMOS technology built over a lightly doped substrate. This approach keeps the advantages usually offered by Monolithic Active Pixel Sensors (MAPS), like a low input capacitance, having a single piece detector and using a standard CMOS production line, and adds the benefit of charge collection by drift from a depleted region several tens of microns deep into the substrate, therefore providing an excellent signal to noise ratio and a radiation tolerance superior to conventional un-depleted MAPS. Such sensors are expected to offer significant cost savings and reduction of power consumption for the same performance, leading to the use of much less material in the detector (less cooling and less copper), addressing one of the main limitations of present day particle tracking systems. The latest evolution of the project uses detectors thinned down to 50 μm to obtain back illuminated sensors operated in full depletion mode. By back-processing the chip and collecting the charge from the full substrate it is hence possible to efficiently detect soft X-rays up to 10 keV. Test results from first successfully processed detectors will be presented and discussed

Small Pixel Hybrid CMOS X-ray Detectors

Science.gov (United States)

Hull, Samuel; Bray, Evan; Burrows, David N.; Chattopadhyay, Tanmoy; Falcone, Abraham; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

2018-01-01

Concepts for future space-based X-ray observatories call for a large effective area and high angular resolution instrument to enable precision X-ray astronomy at high redshift and low luminosity. Hybrid CMOS detectors are well suited for such high throughput instruments, and the Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors, has recently developed new small pixel hybrid CMOS X-ray detectors. These prototype 128x128 pixel devices have 12.5 micron pixel pitch, 200 micron fully depleted depth, and include crosstalk eliminating CTIA amplifiers and in-pixel correlated double sampling (CDS) capability. We report on characteristics of these new detectors, including the best read noise ever measured for an X-ray hybrid CMOS detector, 5.67 e- (RMS).

LISe pixel detector for neutron imaging

Energy Technology Data Exchange (ETDEWEB)

Herrera, Elan; Hamm, Daniel [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Wiggins, Brenden [Technology Development, Y-12 National Security Complex, Oak Ridge, TN (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Milburn, Rob [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Burger, Arnold [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Department of Life and Physical Sciences, Fisk University, Nashville, TN (United States); Bilheux, Hassina [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Santodonato, Louis [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Chvala, Ondrej [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Stowe, Ashley [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States); Technology Development, Y-12 National Security Complex, Oak Ridge, TN (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN (United States); Lukosi, Eric, E-mail: elukosi@utk.edu [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN (United States)

2016-10-11

Semiconducting lithium indium diselenide, {sup 6}LiInSe{sub 2} or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of {sup 6}Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 µm pitch on a 5×5×0.56 mm{sup 3} LISe substrate. An experimentally verified spatial resolution of 300 µm was observed utilizing a super-sampling technique.

Pixel-by-pixel mean transit time without deconvolution.

Science.gov (United States)

Dobbeleir, Andre A; Piepsz, Amy; Ham, Hamphrey R

2008-04-01

Mean transit time (MTT) within a kidney is given by the integral of the renal activity on a well-corrected renogram between time zero and time t divided by the integral of the plasma activity between zero and t, providing that t is close to infinity. However, as the data acquisition of a renogram is finite, the MTT calculated using this approach might result in the underestimation of the true MTT. To evaluate the degree of this underestimation we conducted a simulation study. One thousand renograms were created by convoluting various plasma curves obtained from patients with different renal clearance levels with simulated retentions curves having different shapes and mean transit times. For a 20 min renogram, the calculated MTT started to underestimate the MTT when the MTT was higher than 6 min. The longer the MTT, the greater was the underestimation. Up to a MTT value of 6 min, the error on the MTT estimation is negligible. As normal cortical transit is less than 2 min, this approach is used for patients to calculate pixel-to-pixel cortical mean transit time and to create a MTT parametric image without deconvolution.

Random On-Board Pixel Sampling (ROPS) X-Ray Camera

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhehui [Los Alamos; Iaroshenko, O. [Los Alamos; Li, S. [Los Alamos; Liu, T. [Fermilab; Parab, N. [Argonne (main); Chen, W. W. [Purdue U.; Chu, P. [Los Alamos; Kenyon, G. [Los Alamos; Lipton, R. [Fermilab; Sun, K.-X. [Nevada U., Las Vegas

2017-09-25

Recent advances in compressed sensing theory and algorithms offer new possibilities for high-speed X-ray camera design. In many CMOS cameras, each pixel has an independent on-board circuit that includes an amplifier, noise rejection, signal shaper, an analog-to-digital converter (ADC), and optional in-pixel storage. When X-ray images are sparse, i.e., when one of the following cases is true: (a.) The number of pixels with true X-ray hits is much smaller than the total number of pixels; (b.) The X-ray information is redundant; or (c.) Some prior knowledge about the X-ray images exists, sparse sampling may be allowed. Here we first illustrate the feasibility of random on-board pixel sampling (ROPS) using an existing set of X-ray images, followed by a discussion about signal to noise as a function of pixel size. Next, we describe a possible circuit architecture to achieve random pixel access and in-pixel storage. The combination of a multilayer architecture, sparse on-chip sampling, and computational image techniques, is expected to facilitate the development and applications of high-speed X-ray camera technology.

A Dual-Mode Large-Arrayed CMOS ISFET Sensor for Accurate and High-Throughput pH Sensing in Biomedical Diagnosis.

Science.gov (United States)

Huang, Xiwei; Yu, Hao; Liu, Xu; Jiang, Yu; Yan, Mei; Wu, Dongping

2015-09-01

The existing ISFET-based DNA sequencing detects hydrogen ions released during the polymerization of DNA strands on microbeads, which are scattered into microwell array above the ISFET sensor with unknown distribution. However, false pH detection happens at empty microwells due to crosstalk from neighboring microbeads. In this paper, a dual-mode CMOS ISFET sensor is proposed to have accurate pH detection toward DNA sequencing. Dual-mode sensing, optical and chemical modes, is realized by integrating a CMOS image sensor (CIS) with ISFET pH sensor, and is fabricated in a standard 0.18-μm CIS process. With accurate determination of microbead physical locations with CIS pixel by contact imaging, the dual-mode sensor can correlate local pH for one DNA slice at one location-determined microbead, which can result in improved pH detection accuracy. Moreover, toward a high-throughput DNA sequencing, a correlated-double-sampling readout that supports large array for both modes is deployed to reduce pixel-to-pixel nonuniformity such as threshold voltage mismatch. The proposed CMOS dual-mode sensor is experimentally examined to show a well correlated pH map and optical image for microbeads with a pH sensitivity of 26.2 mV/pH, a fixed pattern noise (FPN) reduction from 4% to 0.3%, and a readout speed of 1200 frames/s. A dual-mode CMOS ISFET sensor with suppressed FPN for accurate large-arrayed pH sensing is proposed and demonstrated with state-of-the-art measured results toward accurate and high-throughput DNA sequencing. The developed dual-mode CMOS ISFET sensor has great potential for future personal genome diagnostics with high accuracy and low cost.

Algorithms for spectral calibration of energy-resolving small-pixel detectors

International Nuclear Information System (INIS)

Scuffham, J; Veale, M C; Wilson, M D; Seller, P

2013-01-01

Small pixel Cd(Zn)Te detectors often suffer from inter-pixel variations in gain, resulting in shifts in the individual energy spectra. These gain variations are mainly caused by inclusions and defects within the crystal structure, which affect the charge transport within the material causing a decrease in the signal pulse height. In imaging applications, spectra are commonly integrated over a particular peak of interest. This means that the individual pixels must be accurately calibrated to ensure that the same portion of the spectrum is integrated in every pixel. The development of large-area detectors with fine pixel pitch necessitates automated algorithms for this spectral calibration, due to the very large number of pixels. Algorithms for automatic spectral calibration require accurate determination of characteristic x-ray or photopeak positions on a pixelwise basis. In this study, we compare two peak searching spectral calibration algorithms for a small-pixel CdTe detector in gamma spectroscopic imaging. The first algorithm uses rigid search ranges to identify peaks in each pixel spectrum, based on the average peak positions across all pixels. The second algorithm scales the search ranges on the basis of the position of the highest-energy peak relative to the average across all pixels. In test spectra acquired with Tc-99m, we found that the rigid search algorithm failed to correctly identify the target calibraton peaks in up to 4% of pixels. In contrast, the scaled search algorithm failed in only 0.16% of pixels. Failures in the scaled search algorithm were attributed to the presence of noise events above the main photopeak, and possible non-linearities in the spectral response in a small number of pixels. We conclude that a peak searching algorithm based on scaling known peak spacings is simple to implement and performs well for the spectral calibration of pixellated radiation detectors

Combining the Pixel-based and Object-based Methods for Building Change Detection Using High-resolution Remote Sensing Images

Directory of Open Access Journals (Sweden)

ZHANG Zhiqiang

2018-01-01

Full Text Available Timely and accurate change detection of buildings provides important information for urban planning and management.Accompanying with the rapid development of satellite remote sensing technology,detecting building changes from high-resolution remote sensing images have received wide attention.Given that pixel-based methods of change detection often lead to low accuracy while object-based methods are complicated for uses,this research proposes a method that combines pixel-based and object-based methods for detecting building changes from high-resolution remote sensing images.First,based on the multiple features extracted from the high-resolution images,a random forest classifier is applied to detect changed building at the pixel level.Then,a segmentation method is applied to segement the post-phase remote sensing image and to get post-phase image objects.Finally,both changed building at the pixel level and post-phase image objects are fused to recognize the changed building objects.Multi-temporal QuickBird images are used as experiment data for building change detection with high-resolution remote sensing images,the results indicate that the proposed method could reduce the influence of environmental difference,such as light intensity and view angle,on building change detection,and effectively improve the accuracies of building change detection.

Steganography based on pixel intensity value decomposition

Science.gov (United States)

Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

2014-05-01

This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

Science.gov (United States)

Kato, T.; Kataoka, J.; Nakamori, T.; Kishimoto, A.; Yamamoto, S.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.; Ikeda, H.; Kamada, K.

2013-05-01

We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4 × 4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5 × 105 at + 20 °C, gain fluctuation over the entire MPPC device is only ± 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22Na point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

Characteristics and fabrication of Geiger-Mueller counters with thin walls made of treated magnesium - Note about the use of araldite; Caracteristiques et fabrication des compteurs Geiger-Muller a paroi mince en magnesium traite - Note sur l'utilisation de l'araldite

Energy Technology Data Exchange (ETDEWEB)

Charbonnel, A

1949-03-01

This report describes, first, the advantage of magnesium for the manufacturing of Geiger-Mueller counters: suitable for machining and polishing, but strong reactivity with the counter atmosphere in the case of magnesium-rich alloys. Thus, the inside wall of the counter (cylinder of 20 mm diameter and 6 cm length) requires a non-reactive protective coating with excellent sealing properties. The synthetic resin 'araldite' fulfills all these conditions. The second part of the report describes the different steps of the fabrication of magnesium wall counters: lathe work, machining down and chemical polishing of hulls, assembly, tight sealing, pumping, filling-up and control tests. The average service life of these counters is of about 4 months. A note about the use and properties (hardening, mechanical properties, resistance..) of araldite is given in appendix. (J.S.)

ALPIDE: the Monolithic Active Pixel Sensor for the ALICE ITS upgrade

International Nuclear Information System (INIS)

Šuljić, M.

2016-01-01

The upgrade of the ALICE vertex detector, the Inner Tracking System (ITS), is scheduled to be installed during the next long shutdown period (2019-2020) of the CERN Large Hadron Collider (LHC) . The current ITS will be replaced by seven concentric layers of Monolithic Active Pixel Sensors (MAPS) with total active surface of ∼10 m 2 , thus making ALICE the first LHC experiment implementing MAPS detector technology on a large scale. The ALPIDE chip, based on TowerJazz 180 nm CMOS Imaging Process, is being developed for this purpose. A particular process feature, the deep p-well, is exploited so the full CMOS logic can be implemented over the active sensor area without impinging on the deposited charge collection. ALPIDE is implemented on silicon wafers with a high resistivity epitaxial layer. A single chip measures 15 mm by 30 mm and contains half a million pixels distributed in 512 rows and 1024 columns. In-pixel circuitry features amplification, shaping, discrimination and multi-event buffering. The readout is hit driven i.e. only addresses of hit pixels are sent to the periphery. The upgrade of the ITS presents two different sets of requirements for sensors of the inner and of the outer layers due to the significantly different track density, radiation level and active detector surface. The ALPIDE chip fulfils the stringent requirements in both cases. The detection efficiency is higher than 99%, fake-hit probability is orders of magnitude lower than the required 10 −6 and spatial resolution within the required 5 μm. This performance is to be maintained even after a total ionising does (TID) of 2.7 Mrad and a non-ionising energy loss (NIEL) fluence of 1.7 × 10 13 1 MeV n eq /cm 2 , which is above what is expected during the detector lifetime. Readout rate of 100 kHz is provided and the power density of ALPIDE is less than 40 mW/cm 2 . This contribution will provide a summary of the ALPIDE features and main test results.

ALPIDE: the Monolithic Active Pixel Sensor for the ALICE ITS upgrade

Science.gov (United States)

Šuljić, M.

2016-11-01

The upgrade of the ALICE vertex detector, the Inner Tracking System (ITS), is scheduled to be installed during the next long shutdown period (2019-2020) of the CERN Large Hadron Collider (LHC) . The current ITS will be replaced by seven concentric layers of Monolithic Active Pixel Sensors (MAPS) with total active surface of ~10 m2, thus making ALICE the first LHC experiment implementing MAPS detector technology on a large scale. The ALPIDE chip, based on TowerJazz 180 nm CMOS Imaging Process, is being developed for this purpose. A particular process feature, the deep p-well, is exploited so the full CMOS logic can be implemented over the active sensor area without impinging on the deposited charge collection. ALPIDE is implemented on silicon wafers with a high resistivity epitaxial layer. A single chip measures 15 mm by 30 mm and contains half a million pixels distributed in 512 rows and 1024 columns. In-pixel circuitry features amplification, shaping, discrimination and multi-event buffering. The readout is hit driven i.e. only addresses of hit pixels are sent to the periphery. The upgrade of the ITS presents two different sets of requirements for sensors of the inner and of the outer layers due to the significantly different track density, radiation level and active detector surface. The ALPIDE chip fulfils the stringent requirements in both cases. The detection efficiency is higher than 99%, fake-hit probability is orders of magnitude lower than the required 10-6 and spatial resolution within the required 5 μm. This performance is to be maintained even after a total ionising does (TID) of 2.7 Mrad and a non-ionising energy loss (NIEL) fluence of 1.7 × 1013 1 MeV neq/cm2, which is above what is expected during the detector lifetime. Readout rate of 100 kHz is provided and the power density of ALPIDE is less than 40 mW/cm2. This contribution will provide a summary of the ALPIDE features and main test results.

Microscope mode secondary ion mass spectrometry imaging with a Timepix detector.

NARCIS (Netherlands)

Kiss, A.; Jungmann, JH; Smith, D.F.; Heeren, R.M.A.

2013-01-01

In-vacuum active pixel detectors enable high sensitivity, highly parallel time- and space-resolved detection of ions from complex surfaces. For the first time, a Timepix detector assembly was combined with a secondary ion mass spectrometer for microscope mode secondary ion mass spectrometry (SIMS)

Online Multi-Spectral Meat Inspection

DEFF Research Database (Denmark)

Nielsen, Jannik Boll; Larsen, Anders Boesen Lindbo

2013-01-01

We perform an explorative study on multi-spectral image data from a prototype device developed for fast online quality inspection of meat products. Because the camera setup is built for speed, we sacrifice exact pixel correspondences between the different bands of the multi-spectral images. Our...... work is threefold as we 1) investigate the color distributions and construct a model to describe pork loins, 2) classify the different components in pork loins (meat, fat, membrane), and 3) detect foreign objects on the surface of pork loins. Our investigation shows that the color distributions can...

The FE-I4 pixel readout integrated circuit

Energy Technology Data Exchange (ETDEWEB)

Garcia-Sciveres, M., E-mail: mgarcia-sciveres@bl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Arutinov, D.; Barbero, M. [University of Bonn, Bonn (Germany); Beccherle, R. [Istituto Nazionale di Fisica Nucleare Sezione di Genova, Genova (Italy); Dube, S.; Elledge, D. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Fleury, J. [Laboratoire de l' Accelerateur Lineaire, Orsay (France); Fougeron, D.; Gensolen, F. [Centre de Physique des Particules de Marseille, Marseille (France); Gnani, D. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gromov, V. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands); Hemperek, T.; Karagounis, M. [University of Bonn, Bonn (Germany); Kluit, R. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands); Kruth, A. [University of Bonn, Bonn (Germany); Mekkaoui, A. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Menouni, M. [Centre de Physique des Particules de Marseille, Marseille (France); Schipper, J.-D. [Nationaal Instituut voor Subatomaire Fysica, Amsterdam (Netherlands)

2011-04-21

A new pixel readout integrated circuit denominated FE-I4 is being designed to meet the requirements of ATLAS experiment upgrades. It will be the largest readout IC produced to date for particle physics applications, filling the maximum allowed reticle area. This will significantly reduce the cost of future hybrid pixel detectors. In addition, FE-I4 will have smaller pixels and higher rate capability than the present generation of LHC pixel detectors. Design features are described along with simulation and test results, including low power and high rate readout architecture, mixed signal design strategy, and yield hardening.