Science.gov

Sample records for pixel detector qualifizierungsmessungen

  1. SOI monolithic pixel detector

    NASA Astrophysics Data System (ADS)

    Miyoshi, T.; Ahmed, M. I.; Arai, Y.; Fujita, Y.; Ikemoto, Y.; Takeda, A.; Tauchi, K.

    2014-05-01

    We are developing monolithic pixel detector using fully-depleted (FD) silicon-on-insulator (SOI) pixel process technology. The SOI substrate is high resistivity silicon with p-n junctions and another layer is a low resistivity silicon for SOI-CMOS circuitry. Tungsten vias are used for the connection between two silicons. Since flip-chip bump bonding process is not used, high sensor gain in a small pixel area can be obtained. In 2010 and 2011, high-resolution integration-type SOI pixel sensors, DIPIX and INTPIX5, have been developed. The characterizations by evaluating pixel-to-pixel crosstalk, quantum efficiency (QE), dark noise, and energy resolution were done. A phase-contrast imaging was demonstrated using the INTPIX5 pixel sensor for an X-ray application. The current issues and future prospect are also discussed.

  2. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

    The present document is a brief summary of the performed activities during the 2001 Summer Student Programme at CERN under the Scientific Summer at Foreign Laboratories Program organized by the Particles and Fields Division of the Mexican Physical Society (Sociedad Mexicana de Fisica). In this case, the activities were related with the ALICE Pixel Group of the EP-AIT Division, under the supervision of Jeroen van Hunen, research fellow in this group. First, I give an introduction and overview to the ALICE experiment; followed by a description of wafer probing. A brief summary of the test beam that we had from July 13th to July 25th is given as well.

  3. Microradiography with Semiconductor Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Jakubek, Jan; Cejnarova, Andrea; Dammer, Jiří; Holý, Tomáš; Platkevič, Michal; Pospíšil, Stanislav; Vavřík, Daniel; Vykydal, Zdeněk

    2007-11-01

    High resolution radiography (with X-rays, neutrons, heavy charged particles, …) often exploited also in tomographic mode to provide 3D images stands as a powerful imaging technique for instant and nondestructive visualization of fine internal structure of objects. Novel types of semiconductor single particle counting pixel detectors offer many advantages for radiation imaging: high detection efficiency, energy discrimination or direct energy measurement, noiseless digital integration (counting), high frame rate and virtually unlimited dynamic range. This article shows the application and potential of pixel detectors (such as Medipix2 or TimePix) in different fields of radiation imaging.

  4. The FPGA Pixel Array Detector

    NASA Astrophysics Data System (ADS)

    Hromalik, Marianne S.; Green, Katherine S.; Philipp, Hugh T.; Tate, Mark W.; Gruner, Sol M.

    2013-02-01

    A proposed design for a reconfigurable x-ray Pixel Array Detector (PAD) is described. It operates by integrating a high-end commercial field programmable gate array (FPGA) into a 3-layer device along with a high-resistivity diode detection layer and a custom, application-specific integrated circuit (ASIC) layer. The ASIC layer contains an energy-discriminating photon-counting front end with photon hits streamed directly to the FPGA via a massively parallel, high-speed data connection. FPGA resources can be allocated to perform user defined tasks on the pixel data streams, including the implementation of a direct time autocorrelation function (ACF) with time resolution down to 100 ns. Using the FPGA at the front end to calculate the ACF reduces the required data transfer rate by several orders of magnitude when compared to a fast framing detector. The FPGA-ASIC high-speed interface, as well as the in-FPGA implementation of a real-time ACF for x-ray photon correlation spectroscopy experiments has been designed and simulated. A 16×16 pixel prototype of the ASIC has been fabricated and is being tested.

  5. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  6. Optical links for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stucci, Stefania

    2016-07-01

    With the expected increase in the instantaneous luminosity of the LHC in the next few years, the off-detector optical read-out system of the outer two layers of the Pixel Detector of the ATLAS experiment will reach its bandwidth limits. The bandwidth will be increased with new optical receivers, which had to be redesigned since commercial solutions could not be used. The new design allows for a wider operational range in terms of data frequency and input optical power to match the on-detector transmitters of the present Pixel Detector. We report on the design and testing of prototypes of these components and the plans for the installation in the Pixel Detector read-out chain in 2015.

  7. The Silicon Pixel Detector for ALICE Experiment

    SciTech Connect

    Fabris, D.; Bombonati, C.; Dima, R.; Lunardon, M.; Moretto, S.; Pepato, A.; Bohus, L. Sajo; Scarlassara, F.; Segato, G.; Shen, D.; Turrisi, R.; Viesti, G.; Anelli, G.; Boccardi, A.; Burns, M.; Campbell, M.; Ceresa, S.; Conrad, J.; Kluge, A.; Kral, M.

    2007-10-26

    The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm{sup 2}. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

  8. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

    Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.

  9. Development of a CMOS SOI Pixel Detector

    SciTech Connect

    Arai, Y.; Hazumi, M.; Ikegami, Y.; Kohriki, T.; Tajima, O.; Terada, S.; Tsuboyama, T.; Unno, Y.; Ushiroda, Y.; Ikeda, H.; Hara, K.; Ishino, H.; Kawasaki, T.; Miyake, H.; Martin, E.; Varner, G.; Tajima, H.; Ohno, M.; Fukuda, K.; Komatsubara, H.; Ida, J.; /NONE - OKI ELECTR INDUST TOKYO

    2008-08-19

    We have developed a monolithic radiation pixel detector using silicon on insulator (SOI) with a commercial 0.15 {micro}m fully-depleted-SOI technology and a Czochralski high resistivity silicon substrate in place of a handle wafer. The SOI TEG (Test Element Group) chips with a size of 2.5 x 2.5 mm{sup 2} consisting of 20 x 20 {micro}m{sup 2} pixels have been designed and manufactured. Performance tests with a laser light illumination and a {beta} ray radioactive source indicate successful operation of the detector. We also briefly discuss the back gate effect as well as the simulation study.

  10. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

    The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented.

  11. Modulation transfer function of a trapezoidal pixel array detector

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Guo, Rongli; Ni, Jinping; Dong, Tao

    2016-01-01

    The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Recently, trapezoid-shaped pixels were designed and used in a retina-like sensor in place of rectangular-shaped pixels. The MTF of a detector with a trapezoidal pixel array is determined according to its definition. Additionally, the MTFs of detectors with differently shaped pixels, but the same pixel areas, are compared. The results show that the MTF values of the trapezoidal pixel array detector are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies.

  12. Radiation experience with the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Veszpremi, V.

    2015-04-01

    The CMS pixel detector is the innermost component of the CMS tracker occupying the region around the centre of CMS, where the LHC beams are crossed, between 4.3 cm and 30 cm in radius and 46.5 cm along the beam axis. It operates in a high-occupancy and high-radiation environment created by particle collisions. Studies of radiation damage effects to the sensors were performed throughout the first running period of the LHC . Leakage current, depletion voltage, pixel readout thresholds, and hit finding efficiencies were monitored as functions of the increasing particle fluence. The methods and results of these measurements will be described together with their implications to detector operation as well as to performance parameters in offline hit reconstruction.

  13. The LAMBDA photon-counting pixel detector

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Lange, S.; Smoljanin, S.; Hirsemann, H.; Graafsma, H.; Epple, M.; Zuvic, M.; Lampert, M.-O.; Fritzsch, T.; Rothermund, M.

    2013-03-01

    The Medipix3 photon-counting detector chip has a number of novel features that are attractive for synchrotron experiments, such as a high frame rate with zero dead time and high spatial resolution. DESY are developing a large-area Medipix3-based detector array (LAMBDA). A single LAMBDA module consists of 2 by 6 Medipix3 chips on a ceramic carrier board, bonded to either a single large silicon sensor or two smaller high-Z sensors. The readout system fits behind the carrier board to allow module tiling, and uses a large on-board RAM and multiple 10 Gigabit Ethernet links to permit high-speed readout. Currently, the first large silicon modules have been constructed and read out at low speed, and the firmware for highspeed readout is being developed. In addition to these silicon sensors, we are developing a germanium hybrid pixel detector in collaboration with Canberra for higher-energy beamlines. Canberra have produced a set of 256-by-256-pixel planar germanium sensors with 55μm pitch, and these are currently being bonded to Medipix3 readout chips by Fraunhofer IZM (Berlin).

  14. The status of the CMS forward pixel detector

    SciTech Connect

    Tan, Ping; /Fermilab

    2006-01-01

    The silicon pixel detector is the innermost component of the CMS tracking system. It provides precise measurements of space points to allow effective pattern recognition in multiple track environments near the LHC interaction point. The end disks of the pixel detector, known as the Forward Pixel detector, are constructed mainly by the US-CMS collaborators. The design techniques, readout electronics, test beam activities, and construction status are reviewed.

  15. Operational experience with the ATLAS Pixel Detector at the LHC

    NASA Astrophysics Data System (ADS)

    Lapoire, C.; Atlas Collaboration

    2013-01-01

    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 paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy is sufficiently low and hit efficiency exceed the design specification.

  16. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  17. Small pixel CZT detector for hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  18. Detector apparatus having a hybrid pixel-waveform readout system

    SciTech Connect

    Meng, Ling-Jian

    2014-10-21

    A gamma ray detector apparatus comprises a solid state detector that includes a plurality of anode pixels and at least one cathode. The solid state detector is configured for receiving gamma rays during an interaction and inducing a signal in an anode pixel and in a cathode. An anode pixel readout circuit is coupled to the plurality of anode pixels and is configured to read out and process the induced signal in the anode pixel and provide triggering and addressing information. A waveform sampling circuit is coupled to the at least one cathode and configured to read out and process the induced signal in the cathode and determine energy of the interaction, timing of the interaction, and depth of interaction.

  19. Data encoding efficiency in pixel detector readout with charge information

    NASA Astrophysics Data System (ADS)

    Garcia-Sciveres, Maurice; Wang, Xinkang

    2016-04-01

    The average minimum number of bits needed for lossless readout of a pixel detector is calculated, in the regime of interest for particle physics where only a small fraction of pixels have a non-zero value per frame. This permits a systematic comparison of the readout efficiency of different encoding implementations. The calculation is compared to the number of bits used by the FE-I4 pixel readout chip of the ATLAS experiment.

  20. Synchrotron beam test with a photon-counting pixel detector.

    PubMed

    Brönnimann, C; Florin, S; Lindner, M; Schmitt, B; Schulze-Briese, C

    2000-09-01

    Synchrotron beam measurements were performed with a single-photon-counting pixel detector to investigate the influence of threshold settings on charge sharing. Improvement of image homogeneity by adjusting the threshold of each pixel individually was demonstrated. With a flat-field correction, the homogeneity could be improved. A measurement of the point spread function is reported. PMID:16609212

  1. Monolithic pixel detectors in silicon on insulator technology

    NASA Astrophysics Data System (ADS)

    Bisello, Dario

    2013-05-01

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  2. Operational experience with the ATLAS Pixel detector at the LHC

    NASA Astrophysics Data System (ADS)

    Deluca, C.

    2011-12-01

    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 pico-seconds lifetime 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: 97.5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, and a good alignment allows high quality track resolution.

  3. Single photon counting pixel detectors for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Toyokawa, H.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Kawase, M.; Kobas, M.; Kraft, P.; Sato, M.; Schmitt, B.; Suzuki, M.; Tanida, H.; Uruga, T.

    2010-11-01

    At the Paul Scherrer Institute PSI an X-ray single photon counting pixel detector (PILATUS) based on the hybrid-pixel detector technology was developed in collaboration with SPring-8. The detection element is a 320 or 450 μm thick silicon sensor forming pixelated pn-diodes with a pitch of 172 μm×172 μm. An array of 2×8 custom CMOS readout chips are indium bump-bonded to the sensor, which leads to 33.5 mm×83.8 mm detective area. Each pixel contains a charge-sensitive amplifier, a single level discriminator and a 20 bit counter. This design realizes a high dynamic range, short readout time of less than 3 ms, a high framing rate of over 200 images per second and an excellent point-spread function. The maximum counting rate achieves more than 2×10 6 X-rays/s/pixel.

  4. DAQ hardware and software development for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    In 2014, the Pixel Detector of the ATLAS experiment has been extended by about 12 million pixels thanks to the installation of the Insertable B-Layer (IBL). Data-taking and tuning procedures have been implemented along with newly designed readout hardware to support high bandwidth for data readout and calibration. The hardware is supported by an embedded software stack running on the readout boards. The same boards will be used to upgrade the readout bandwidth for the two outermost barrel layers of the ATLAS Pixel Detector. We present the IBL readout hardware and the supporting software architecture used to calibrate and operate the 4-layer ATLAS Pixel Detector. We discuss the technical implementations and status for data taking, validation of the DAQ system in recent cosmic ray data taking, in-situ calibrations, and results from additional tests in preparation for Run 2 at the LHC.

  5. Challenges of small-pixel infrared detectors: a review

    NASA Astrophysics Data System (ADS)

    Rogalski, A.; Martyniuk, P.; Kopytko, M.

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology—HgCdTe material systems and III-V materials (mainly barrier detectors)—have been investigated.

  6. Challenges of small-pixel infrared detectors: a review.

    PubMed

    Rogalski, A; Martyniuk, P; Kopytko, M

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology-HgCdTe material systems and III-V materials (mainly barrier detectors)-have been investigated. PMID:27007242

  7. Development of pixel detectors for SSC vertex tracking

    SciTech Connect

    Kramer, G. . Electro-Optical and Data Systems Group); Atlas, E.L.; Augustine, F.; Barken, O.; Collins, T.; Marking, W.L.; Worley, S.; Yacoub, G.Y. ) Shapiro, S.L. ); Arens, J.F.; Jernigan, J.G. . Space Sciences Lab.); Nygren,

    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 {times} 256 pixels, each 30 {mu}m 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.

  8. The BTeV pixel detector and trigger system

    SciTech Connect

    Simon Kwan

    2002-12-03

    BTeV is an approved forward collider experiment at the Fermilab Tevatron dedicated to the precision studies of CP violation, mixing, and rare decays of beauty and charm hadrons. The BTeV detector has been designed to achieve these goals. One of the unique features of BTeV is a state-of-the-art pixel detector system, designed to provide accurate measurements of the decay vertices of heavy flavor hadrons that can be used in the first trigger level. The pixel vertex detector and the trigger design are described. Recent results on some of the achievements in the R and D effort are presented.

  9. Velocity map imaging using an in-vacuum pixel detector

    NASA Astrophysics Data System (ADS)

    Gademann, Georg; Huismans, Ymkje; Gijsbertsen, Arjan; Jungmann, Julia; Visschers, Jan; Vrakking, Marc J. J.

    2009-10-01

    The use of a new type in-vacuum pixel detector in velocity map imaging (VMI) is introduced. The Medipix2 and Timepix semiconductor pixel detectors (256×256 square pixels, 55×55 μm2) are well suited for charged particle detection. They offer high resolution, low noise, and high quantum efficiency. The Medipix2 chip allows double energy discrimination by offering a low and a high energy threshold. The Timepix detector allows to record the incidence time of a particle with a temporal resolution of 10 ns and a dynamic range of 160 μs. Results of the first time application of the Medipix2 detector to VMI are presented, investigating the quantum efficiency as well as the possibility to operate at increased background pressure in the vacuum chamber.

  10. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  11. Rework of flip chip bonded radiation pixel detectors

    NASA Astrophysics Data System (ADS)

    Vähänen, S.; Heikkinen, H.; Pohjonen, H.; Salonen, J.; Savolainen-Pulli, S.

    2008-06-01

    In this paper, some practical aspects of reworking flip chip hybridized pixel detectors are discussed. As flip chip technology has been advancing in terms of placement accuracy and reliability, large-area hybrid pixel detectors have been developed. The area requirements are usually fulfilled by placing several readout chips (ROCs) on single sensor chip. However, as the number of ROCs increases, the probability of failure in the hybridization process and the ROC operation also increases. Because high accuracy flip chip bonding takes time, a significant part of the price of a pixel detector comes from the flip chip assembly process itself. As large-area detector substrates are expensive, and many flip chip placements are required, the price of an assembled detector can become very high. In a typical case, there is just one bad ROC (out of several) on a faulty detector to be replaced. Considering the high price of pixel detectors and the fact that reworking faulty ROCs does not take much longer than the original placement, it is worthwhile to investigate the feasibility of a rework process.

  12. Impact of CT detector pixel-to-pixel crosstalk on image quality

    NASA Astrophysics Data System (ADS)

    Engel, Klaus J.; Spies, Lothar; Vogtmeier, Gereon; Luhta, Randy

    2006-03-01

    In Computed Tomography (CT), the image quality sensitively depends on the accuracy of the X-ray projection signal, which is acquired by a two-dimensional array of pixel cells in the detector. If the signal of X-ray photons is spread out to neighboring pixels (crosstalk), a decrease of spatial resolution may result. Moreover, streak and ring artifacts may emerge. Deploying system simulations for state-of-the-art CT detector configurations, we characterize origin and appearance of these artifacts in the reconstructed CT images for different scenarios. A uniform pixel-to-pixel crosstalk results in a loss of spatial resolution only. The Modulation Transfer Function (MTF) is attenuated, without affecting the limiting resolution, which is defined as the first zero of the MTF. Additional streak and ring artifacts appear, if the pixel-to-pixel crosstalk is non-uniform. Parallel to the system simulations we developed an analytical model. The model explains resolution loss and artifact level using the first and second derivative of the X-ray profile acquired by the detector. Simulations and analytical model are in agreement to each other. We discuss the perceptibility of ring and streak artifacts within noisy images if no crosstalk correction is applied.

  13. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Katoh, Kouji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2011-06-01

    Since authors have successfully demonstrated uncooled infrared (IR) focal plane array (FPA) with 23.5 um pixel pitch, it has been widely utilized for commercial applications such as thermography, security camera and so on. One of the key issues for uncooled IR detector technology is to shrink the pixel size. The smaller the pixel pitch, the more the IR camera products become compact and the less cost. This paper proposes a new pixel structure with a diaphragm and beams which are placed in different level, to realize an uncooled IRFPA with smaller pixel pitch )<=17 μm). The upper level consists of diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to place on the adjacent pixels. The test devices of this pixel design with 12 um, 15 um and 17 um pitch have been fabricated on the Si ROIC of QVGA (320 × 240) with 23.5 um pitch. Their performances reveal nearly equal to the IRFPA with 23.5 um pitch. For example, noise equivalent temperature difference (NETD) of 12 μm pixel is 63.1 mK with thermal time constant of 14.5 msec. In addition, this new structure is expected to be more effective for the existing IRFPA with 23.5 um pitch in order to improve the IR responsivity.

  14. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    SciTech Connect

    Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  15. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    NASA Astrophysics Data System (ADS)

    Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-01

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  16. Polycrystalline CVD diamond pixel array detector for nuclear particles monitoring

    NASA Astrophysics Data System (ADS)

    Pacilli, M.; Allegrini, P.; Girolami, M.; Conte, G.; Spiriti, E.; Ralchenko, V. G.; Komlenok, M. S.; Khomic, A. A.; Konov, V. I.

    2013-02-01

    We report the 90Sr beta response of a polycrystalline diamond pixel detector fabricated using metal-less graphitic ohmic contacts. Laser induced graphitization was used to realize multiple squared conductive contacts with 1mm × 1mm area, 0.2 mm apart, on one detector side while on the other side, for biasing, a 9mm × 9mm large graphite contact was realized. A proximity board was used to wire bonding nine pixels at a time and evaluate the charge collection homogeneity among the 36 detector pixels. Different configurations of biasing were experimented to test the charge collection and noise performance: connecting the pixel at the ground potential of the charge amplifier led to best results and minimum noise pedestal. The expected exponential trend typical of beta particles has been observed. Reversing the bias polarity the pulse height distribution (PHD) does not changes and signal saturation of any pixel was observed around ±200V (0.4 V/μm). Reasonable pixels response uniformity has been evidenced even if smaller pitch 50÷100 μm structures need to be tested.

  17. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  18. Calibration analysis software for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    The calibration of the ATLAS Pixel Detector at LHC fulfils two main purposes: to tune the front-end configuration parameters for establishing the best operational settings and to measure the tuning performance through a subset of scans. An analysis framework has been set up in order to take actions on the detector given the outcome of a calibration scan (e.g. to create a mask for disabling noisy pixels). The software framework to control all aspects of the Pixel Detector scans and analyses is called calibration console. The introduction of a new layer, equipped with new FE-I4 chips, required an update of the console architecture. It now handles scans and scan analyses applied together to chips with different characteristics. An overview of the newly developed calibration analysis software will be presented, together with some preliminary results.

  19. Pixel detectors in 3D technologies for high energy physics

    SciTech Connect

    Deptuch, G.; Demarteau, M.; Hoff, J.; Lipton, R.; Shenai, A.; Yarema, R.; Zimmerman, T.; /Fermilab

    2010-10-01

    This paper reports on the current status of the development of International Linear Collider vertex detector pixel readout chips based on multi-tier vertically integrated electronics. Initial testing results of the VIP2a prototype are presented. The chip is the second embodiment of the prototype data-pushed readout concept developed at Fermilab. The device was fabricated in the MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  20. Modulation transfer function measurement technique for small-pixel detectors

    NASA Technical Reports Server (NTRS)

    Marchywka, Mike; Socker, Dennis G.

    1992-01-01

    A modulation transfer function (MTF) measurement technique suitable for large-format, small-pixel detector characterization has been investigated. A volume interference grating is used as a test image instead of the bar or sine wave target images normally used. This technique permits a high-contrast, large-area, sinusoidal intensity distribution to illuminate the device being tested, avoiding the need to deconvolve raw data with imaging system characteristics. A high-confidence MTF result at spatial frequencies near 200 cycles/mm is obtained. We present results at several visible light wavelengths with a 6.8-micron-pixel CCD. Pixel response functions are derived from the MTF results.

  1. Gas pixel detectors for X-ray polarimetry applications

    NASA Astrophysics Data System (ADS)

    Bellazzini, R.; Angelini, F.; Baldini, L.; Bitti, F.; Brez, A.; Cavalca, F.; Del Prete, M.; Kuss, M.; Latronico, L.; Omodei, N.; Pinchera, M.; Massai, M. M.; Minuti, M.; Razzano, M.; Sgro, C.; Spandre, G.; Tenze, A.; Costa, E.; Soffitta, P.

    2006-05-01

    We discuss a new class of micro pattern gas detectors, the gas pixel detector (GPD), in which a complete integration between the gas amplification structure and the read-out electronics has been reached. An application-specific integrated circuit (ASIC) built in deep sub-micron technology has been developed to realize a monolithic device that is, at the same time, the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics. The CMOS chip has the top metal layer patterned in a matrix of 80 μm pitch hexagonal pixels, each of them directly connected to the underneath electronics chain which has been realized in the remaining five layers of the 0.35 μm VLSI technology. Results from tests of a first prototype of such detector with 2 k pixels and a full scale version with 22 k pixels are presented. The application of this device for Astronomical X-ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation is shown. Results from a full MonteCarlo simulation for two astronomical sources, the Crab Nebula and the Hercules X1, are also reported.

  2. The BTeV pixel and microstrip detector

    SciTech Connect

    Simon W Kwan

    2003-06-04

    The BTeV pixel detector is one of the most crucial elements in the BTeV experiment. While the pixel detector is technically challenging, we have made great progress towards identifying viable solutions for individual components of the system. The forward silicon tracker is based on more mature technology and its design has benefited from the experience of other experiments. Nevertheless, we have started an R&D program on the forward silicon tracker and first results are expected some time next year.

  3. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  4. Overview of the BTeV Pixel Detector

    SciTech Connect

    Jeffrey A Appel

    2002-12-10

    BTeV is a new Fermilab beauty and charm experiment designed to operate in the CZero region of the Tevatron collider. Critical to the success of BTeV is its pixel detector. The unique features of this pixel detector include its proximity to the beam, its operation with a beam crossing time of 132 ns, and the need for the detector information to be read out quickly enough to be used for the lowest level trigger. This talk presents an overview of the pixel detector design, giving the motivations for the technical choices made. The status of the current R&D on detector components is also reviewed. Additional Pixel 2002 talks on the BTeV pixel detector are given by Dave Christian[1], Mayling Wong[2], and Sergio Zimmermann[3]. Table 1 gives a selection of pixel detector parameters for the ALICE, ATLAS, BTeV, and CMS experiments. Comparing the progression of this table, which I have been updating for the last several years, has shown a convergence of specifications. Nevertheless, significant differences endure. The BTeV data-driven readout, horizontal and vertical position resolution better than 9 {micro}m with the {+-} 300 mr forward acceptance, and positioning in vacuum and as close as 6 mm from the circulating beams remain unique. These features are driven by the physics goals of the BTeV experiment. Table 2 demonstrates that the vertex trigger performance made possible by these features is requisite for a very large fraction of the B meson decay physics which is so central to the motivation for BTeV. For most of the physics quantities of interest listed in the table, the vertex trigger is essential. The performance of the BTeV pixel detector may be summarized by looking at particular physics examples; e.g., the B{sub s} meson decay B{sub s} {yields} D{sub s}{sup -} K{sup +}. For that decay, studies using GEANT3 simulations provide quantitative measures of performance. For example, the separation between the B{sub s} decay point and the primary proton

  5. Planar pixel detector module development for the HL-LHC ATLAS pixel system

    NASA Astrophysics Data System (ADS)

    Bates, Richard L.; Buttar, C.; Stewart, A.; Blue, A.; Doonan, K.; Ashby, J.; Casse, G.; Dervan, P.; Forshaw, D.; Tsurin, I.; Brown, S.; Pater, J.

    2013-12-01

    The ATLAS pixel detector for the HL-LHC requires the development of large area pixel modules that can withstand doses up to 1016 1 MeV neq cm-2. The area of the pixel detector system will be over 5 m2 and as such low cost, large area modules are required. The development of a quad module based on 4 FE-I4 readout integrated chips (ROIC) will be discussed. The FE-I4 ROIC is a large area chip and the yield of the flip-chip process to form an assembly is discussed for single chip assemblies. The readout of the quad module for laboratory tests will be reported.

  6. Design Methodology: ASICs with complex in-pixel processing for Pixel Detectors

    SciTech Connect

    Fahim, Farah

    2014-10-31

    The development of Application Specific Integrated Circuits (ASIC) for pixel detectors with complex in-pixel processing using Computer Aided Design (CAD) tools that are, themselves, mainly developed for the design of conventional digital circuits requires a specialized approach. Mixed signal pixels often require parasitically aware detailed analog front-ends and extremely compact digital back-ends with more than 1000 transistors in small areas below 100μm x 100μm. These pixels are tiled to create large arrays, which have the same clock distribution and data readout speed constraints as in, for example, micro-processors. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout.

  7. Pixel Detectors For Diffraction Experiments At The Swiss Light Source

    SciTech Connect

    Huelsen, G.; Eikenberry, E.F.; Schmitt, B.; Schulze-Briese, C.; Tomizaki, T.; Stampanoni, M.; Willmott, P.; Patterson, B.; Broennimann, Ch.; Horisberger, R.; Toyokawa, H.; Borchert, G. L.

    2004-05-12

    The PILATUS detector (Pixel Apparatus for the SLS) is a large, quantum-limited area X-ray detector for protein crystallography which is currently under construction. Its basic units are modules with 16 CMOS chips bump-bonded to a large, continuously sensitive silicon sensor with 157x366 pixels of 217x217 {mu}m2, leading to an active area of 34x80 mm2. With a counting circuit in each pixel, X-rays are detected in single photon counting mode, leading to excellent, noise-free data. The main properties of the detector are an energy range of 6 to 30 keV, no back-ground due to leakage current or readout-noise, fast read-out time of 6.7 ms, a rate/pixel >104/s and a PSF of one pixel. PILATUS detectors are installed at the SLS X06SA protein crystallography beamline, and at both the surface diffraction (SD) station and the radiography and tomography (XTM) station of beamline X04SA. The detectors are operated at room temperature and thus are very easy to use. Experiments benefit from the ability to detect very weak diffraction spots with high precision. At the SD station and at the XTM station, which is equipped with a Bragg magnifier, diffraction, radiography and tomography experiments showed promising results. At beamline X06SA, a three-module array (1120x157 pixels) with a readout time of 6.7 ms was tested. This system was used to collect fine phi-sliced protein crystal data in continuous sample rotation mode in which the crystal was continuously rotated with a slow angular velocity of 0.04 deg./s without any shutter operation. Exposure time per frame ranged from 100 ms to a few seconds, depending on the crystal. These initial experiments show the potential of this method.

  8. Active Pixel Sensor Characterization for the STAR Detector

    NASA Astrophysics Data System (ADS)

    King, Jake

    2004-10-01

    The STAR collaboration is studying matter at high temperatures and densities. If a significant improvement to the measurement of particle trajectories can be made, charmed mesons that decay away from the primary collision point could be identified. To achieve this goal, STAR is building a vertex detector consisting of a new technology Â- active pixel sensors. (APS) An APS is an implementation of standard CMOS technology in which each pixel has a photodiode directly above the epitaxial layer. Incident particles produce electron-hole pairs in the epitaxial layer, and these electrons accumulate on the photodiode. Charge from the photodiode is digitized to identify the position of the incident particle. It is important to characterize the signal to noise, readout time, and resolution on several different pixel sizes so that the vertex detector can be optimized for cost and speed. Larger pixels result in a faster data acquisition, while smaller pixels have better resolution. We will present studies of 5, 10, 20 and 30μm square pixel geometries that measure charge distribution and collection. We will also display the results of using a field emission scanning electron microscope with energies from 1 to 30 keV. This tool has the potential to probe regions of the APS integrated circuit and contribute to understanding its properties.

  9. Readout chip for the CMS pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Rossini, Marco

    2014-11-01

    For the CMS experiment a new pixel detector is planned for installation during the extended shutdown in winter 2016/2017. Among the changes of the detector modified front end electronics will be used for higher efficiency at peak luminosity of the LHC and faster readout. The first prototype versions of the new readout chip have been designed and produced. The results of qualification and calibration for the new chip are presented in this paper.

  10. Pixelated Single-crystal Diamond Detector for fast neutron measurements

    NASA Astrophysics Data System (ADS)

    Rebai, M.; Cazzaniga, C.; Croci, G.; Tardocchi, M.; Perelli Cippo, E.; Calvani, P.; Girolami, M.; Trucchi, D. M.; Grosso, G.; Gorini, G.

    2015-03-01

    Single-crystal Diamond Detectors (SDDs), due to their high radiation hardness, fast response time and small size, are good candidates as fast neutron detectors in those environments where the high neutron flux is an issue, such as spallation neutron sources and the next generation thermonuclear fusion plasmas, i.e. the ITER experiment. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interactions with 12C. Recent measurements have demonstrated the SDD capability of measuring the neutron flux with a good energy resolution and at high rates. In this work a novel detector based on a 12-pixels SDD matrix will be presented. Each pixel is equipped with an independent electronic chain: the fast shaping preamplifier coupled to a digitizer is able to combine the high rate capability and the good energy resolution. Two CAEN digitizers are compared and the possibility of performing good energy resolution measurements (<2%) and at high rates (>1 MHz per channel) is described. Each pixel was characterized and calibrated using an 241Am source: the energy resolution was evaluated and gives a mean value of 1.73% at 5.5 MeV. The good energy resolution achieved and its uniformity between pixels are the demonstration of the capability of this novel detector as a spectrometer. This system will be installed during the next Deuterium-Tritium campaign on a collimated vertical line of sight at JET for 14 MeV neutron measurements.

  11. Precision tracking with a single gaseous pixel detector

    NASA Astrophysics Data System (ADS)

    Tsigaridas, S.; van Bakel, N.; Bilevych, Y.; Gromov, V.; Hartjes, F.; Hessey, N. P.; de Jong, P.; Kluit, R.

    2015-09-01

    The importance of micro-pattern gaseous detectors has grown over the past few years after successful usage in a large number of applications in physics experiments and medicine. We develop gaseous pixel detectors using micromegas-based amplification structures on top of CMOS pixel readout chips. Using wafer post-processing we add a spark-protection layer and a grid to create an amplification region above the chip, allowing individual electrons released above the grid by the passage of ionising radiation to be recorded. The electron creation point is measured in 3D, using the pixel position for (x, y) and the drift time for z. The track can be reconstructed by fitting a straight line to these points. In this work we have used a pixel-readout-chip which is a small-scale prototype of Timepix3 chip (designed for both silicon and gaseous detection media). This prototype chip has several advantages over the existing Timepix chip, including a faster front-end (pre-amplifier and discriminator) and a faster TDC which reduce timewalk's contribution to the z position error. Although the chip is very small (sensitive area of 0.88 × 0.88mm2), we have built it into a detector with a short drift gap (1.3 mm), and measured its tracking performance in an electron beam at DESY. We present the results obtained, which lead to a significant improvement for the resolutions with respect to Timepix-based detectors.

  12. Large format, small pixel pitch and hot detectors at SOFRADIR

    NASA Astrophysics Data System (ADS)

    Reibel, Y.; Rouvie, A.; Nedelcu, A.; Augey, T.; Pere-Laperne, N.; Rubaldo, L.; Billon-Lanfrey, D.; Gravrand, O.; Rothman, J.; Destefanis, G.

    2013-10-01

    Recently Sofradir joined a very small circle of IR detector manufacturers with expertise every aspect of the cooled and uncooled IR technologies, all under one roof by consolidating all IR technologies available in France. These different technologies are complementary and are used depending of the needs of the applications mainly concerning the detection range needs as well as their ability to detect in bad weather environmental conditions. SNAKE (InGaAs) and SCORPIO LW (MCT) expand Sofradir's line of small pixel pitch TV format IR detectors from the mid-wavelength to the short and long wavelengths. Our dual band MW-LW QWIP detectors (25μm, 384×288 pixels) benefit to tactical platforms giving an all-weather performance and increasing flexibility in the presence of battlefield obscurants. In parallel we have been pursuing further infrared developments on future MWIR detectors, such as the VGA format HOT detector that consumes 2W and the 10μm pitch IR detector which gives us a leading position in innovation. These detectors are designed for long-range surveillance equipment, commander or gunner sights, ground-to-ground missile launchers and other applications that require higher resolution and sensitivity to improve reconnaissance and target identification. This paper discusses the system level performance in each detector type.

  13. Sensor Development and Readout Prototyping for the STAR Pixel Detector

    SciTech Connect

    Greiner, L.; Anderssen, E.; Matis, H.S.; Ritter, H.G.; Stezelberger, T.; Szelezniak, M.; Sun, X.; Vu, C.; Wieman, H.

    2009-01-14

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

  14. Use of silicon pixel detectors in double electron capture experiments

    NASA Astrophysics Data System (ADS)

    Cermak, P.; Stekl, I.; Shitov, Yu A.; Mamedov, F.; Rukhadze, E. N.; Jose, J. M.; Cermak, J.; Rukhadze, N. I.; Brudanin, V. B.; Loaiza, P.

    2011-01-01

    A novel experimental approach to search for double electron capture (EC/EC) is discussed in this article. R&D for a new generation EC/EC spectrometer based on silicon pixel detectors (SPDs) has been conducted since 2009 for an upgrade of the TGV experiment. SPDs built on Timepix technology with a spectroscopic readout from each individual pixel are an effective tool to detect the 2νEC/EC signature of the two low energy X-rays hitting two separate pixels. The ability of SPDs to indentify α/β/γ particles and localize them precisely leads to effective background discrimination and thus considerable improvement of the signal-to-background ratio (S/B). A multi-SPD system, called a Silicon Pixel Telescope (SPT), is planned based on the experimental approach of the TGV calorimeter which measures thin foils of enriched EC/EC-isotope sandwiched between HPGe detectors working in coincidence mode. The sources of SPD internal background have been identified by measuring SPD radiopurity with a low-background HPGe detector as well as by long-term SPD background runs in the Modane underground laboratory (LSM, France), and results of these studies are presented.

  15. MTF study of planar small pixel pitch quantum IR detectors

    NASA Astrophysics Data System (ADS)

    Gravrand, O.; Baier, N.; Ferron, A.; Rochette, F.; Berthoz, J.; Rubaldo, L.; Cluzel, R.

    2014-06-01

    The actual trend in quantum IR detector development is the design of very small pixel pitch large arrays. From previously 30μm pitch, the standard pixel pitch is today 15μm and is expected to decrease to 12μm in the next few years. Furthermore, focal plane arrays (FPA) with pixel pitch as small as small as 10μm has been demonstrated. Such ultra-small pixel pitches are very small compared to the typical length ruling the electrical characteristics of the absorbing materials, namely the minority carrier diffusion length. As an example for low doped N type HgCdTe or InSb material, this diffusion length is of the order of 30 to 50μm, i.e. 3 to 5 times the targeted pixel pitches. This has strong consequences on the modulation transfer function (MTF) for planar structures, where the lateral extension of the photodiode is limited by diffusion. For such aspect ratios, the self-confinement of neighboring diodes may not be efficient enough to maintain optimal MTF. Therefore, this issue has to be addressed in order to take full benefits of the pixel pitch reduction in terms of image resolution. This paper aims at investigating the MTF evolution of HgCdTe and InSb FPAs decreasing the pixel pitch below 15μm. Both experimental measurements and finite element simulations are used to discuss this issue. Different scenarii will be compared, namely deep mesa etch between pixels, internal drift, surface recombination, thin absorbing layers.

  16. Recent Developments of HEP Pixel Detector Readout Chips

    NASA Astrophysics Data System (ADS)

    Caminada, Lea

    This article reviews the development of readout integrated circuits for hybrid pixel particle physics detectors. The 250-nm feature size chips in the presently operating ATLAS and CMS experiments are compared with the current state of the art in 130-nm feature size represented by the FE-I4 chip that will be used to add a new beam pipe layer for the ATLAS experiment in 2013 and the upgrade options of the CMS pixel readout chip. This includes a discussion of the array and pixel size, analog performance, readout architecture, power consumption, power distribution options and radiation hardness. Finally, recent work in 65-nm feature size as a means to continue the evolution of readout chip technology towards smaller feature size, higher rate, and lower power is presented.

  17. Modulation transfer function measurement technique for small-pixel detectors.

    PubMed

    Marchywka, M; Socker, D G

    1992-12-01

    A modulation transfer function (MTF) measurement technique suitable for large-format, small-pixel detector characterization has been investigated. A volume interference grating is used as a test image instead of the bar or sine wave target images normally used. This technique permits a high-contrast, large-area, sinusoidal intensity distribution to illuminate the device being tested, avoiding the need to deconvolve raw data with imaging system characteristics. A high-confidence MTF result at spatial frequencies near 200 cycles/mm is obtained. We present results at several visible light wavelengths with a 6.8-microm-pixel CCD. Pixel response functions are derived from the MTF results. PMID:20802584

  18. Characterization of indium and solder bump bonding for pixel detectors

    SciTech Connect

    Selcuk Cihangir and Simon Kwan

    2000-09-28

    A review of different bump-bonding processes used for pixel detectors is given. A large scale test on daisy-chained components from two vendors has been carried out at Fermilab to characterize the yield of these processes. The vendors are Advanced Interconnect Technology Ltd. (AIT) of Hong Kong and MCNC in North Carolina, US. The results from this test are presented and technical challenges encountered are discussed.

  19. Wire bond vibration of forward pixel tracking detector of CMS

    SciTech Connect

    Atac, M.; Gobbi, B.; Kwan, S.; Pischalnikov, Y.; Spencer, E.; Sellberg, G.; Pavlicek, V.; /Fermilab

    2006-10-01

    Wire bonds of the Forward Pixel (FPix) tracking detectors are oriented in the direction that maximizes Lorentz Forces relative to the 4 Tesla field of the Compact Muon Solenoid (CMS) Detector's magnet. The CMS Experiment is under construction at the Large Hadron Collider at CERN, Geneva, Switzerland. We were concerned about Lorentz Force oscillating the wires at their fundamental frequencies and possibly fracturing or breaking them at their heels, as happened with the CDF wire bonds. This paper reports a study to understand what conditions break such bonds.

  20. Monolithic active pixel radiation detector with shielding techniques

    DOEpatents

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  1. Pixel diamond detectors for excimer laser beam diagnostics

    NASA Astrophysics Data System (ADS)

    Girolami, M.; Allegrini, P.; Conte, G.; Salvatori, S.

    2011-05-01

    Laser beam profiling technology in the UV spectrum of light is evolving with the increase of excimer lasers and lamps applications, that span from lithography for VLSI circuits to eye surgery. The development of a beam-profiler, able to capture the excimer laser single pulse and process the acquired pixel current signals in the time period between each pulse, is mandatory for such applications. 1D and 2D array detectors have been realized on polycrystalline CVD diamond specimens. The fast diamond photoresponse, in the ns time regime, suggests the suitability of such devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics, also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The relatively high resistivity of diamond in the dark has allowed the fabrication of photoconductive vertical pixel-detectors. A semitransparent light-receiving back-side contact has been used for detector biasing. Each pixel signal has been conditioned by a multi-channel read-out electronics made up of a high-sensitive integrator and a Σ-Δ A/D converter. The 500 μs conversion time has allowed a data acquisition rate up to 2 kSPS (Sample Per Second).

  2. Small-Scale Readout Systems Prototype for the STAR PIXEL Detector

    SciTech Connect

    Szelezniak, Michal A.; Besson, Auguste; Colledani, Claude; Dorokhov, Andrei; Dulinski, Wojciech; Greiner, Leo C.; Himmi, Abdelkader; Hu, Christine; Matis, Howard S.; Ritter, Hans Georg; Rose, Andrew; Shabetai, Alexandre; Stezelberger, Thorsten; Sun, Xiangming; Thomas, Jim H.; Valin, Isabelle; Vu, Chinh Q.; Wieman, Howard H.; Winter, Marc

    2008-10-01

    A prototype readout system for the STAR PIXEL detector in the Heavy Flavor Tracker (HFT) vertex detector upgrade is presented. The PIXEL detector is a Monolithic Active Pixel Sensor (MAPS) based silicon pixel vertex detector fabricated in a commercial CMOS process that integrates the detector and front-end electronics layers in one silicon die. Two generations ofMAPS prototypes designed specifically for the PIXEL are discussed. We have constructed a prototype telescope system consisting of three small MAPS sensors arranged in three parallel and coaxial planes with a readout system based on the readout architecture for PIXEL. This proposed readout architecture is simple and scales to the size required to readout the final detector. The real-time hit finding algorithm necessary for data rate reduction in the 400 million pixel detector is described, and aspects of the PIXEL system integration into the existing STAR framework are addressed. The complete system has been recently tested and shown to be fully functional.

  3. The data acquisition system of the Belle II Pixel Detector

    NASA Astrophysics Data System (ADS)

    Münchow, D.; Dingfelder, J.; Geßler, T.; Konorov, I.; Kühn, W.; Lange, S.; Lautenbach, K.; Levit, D.; Liu, Z.; Marinas, C.; Schnell, M.; Spruck, B.; Zhao, J.

    2014-08-01

    At the future Belle II experiment the DEPFET (DEPleted Field Effect Transistor) pixel detector will consist of about 8 million channels and is placed as the innermost detector. Because of its small distance to the interaction region and the high luminosity in Belle II, for a trigger rate of about 30 kHz with an estimated occupancy of about 3 % a data rate of about 22 GB/s is expected. Due to the high data rate, a data reduction factor higher than 30 is needed in order to stay inside the specifications of the event builder. The main hardware to reduce the data rate is a xTCA based Compute Node (CN) developed in cooperation between IHEP Beijing and University Giessen. Each node has as main component a Xilinx Virtex-5 FX70T FPGA and is equipped with 2 × 2 GB RAM , GBit Ethernet and 4 × 6.25 Gb/s optical links. An ATCA carrier board is able to hold up to four CN and supplies high bandwidth connections between the four CNs and to the ATCA backplane. To achieve the required data reduction on the CNs, regions of interest (ROI) are used. These regions are calculated in two independent systems by projecting tracks back to the pixel detector. One is the High Level Trigger (HLT) which uses data from the Silicon Vertex Detector (SVD), a silicon strip detector, and outer detectors. The other is the Data Concentrator (DATCON) which calculates ROIs based on SVD data only, in order to get low momentum tracks. With this information, only PXD data inside these ROIs will be forwarded to the event builder, while data outside of these regions will be discarded. First results of the test beam time in January 2014 at DESY with a Belle II vertex detector prototype and full DAQ chain will be presented.

  4. A novel pixellated solid-state photon detector for enhancing the Everhart-Thornley detector.

    PubMed

    Chuah, Joon Huang; Holburn, David

    2013-06-01

    This article presents a pixellated solid-state photon detector designed specifically to improve certain aspects of the existing Everhart-Thornley detector. The photon detector was constructed and fabricated in an Austriamicrosystems 0.35 µm complementary metal-oxide-semiconductor process technology. This integrated circuit consists of an array of high-responsivity photodiodes coupled to corresponding low-noise transimpedance amplifiers, a selector-combiner circuit and a variable-gain postamplifier. Simulated and experimental results show that the photon detector can achieve a maximum transimpedance gain of 170 dBΩ and minimum bandwidth of 3.6 MHz. It is able to detect signals with optical power as low as 10 nW and produces a minimum signal-to-noise ratio (SNR) of 24 dB regardless of gain configuration. The detector has been proven to be able to effectively select and combine signals from different pixels. The key advantages of this detector are smaller dimensions, higher cost effectiveness, lower voltage and power requirements and better integration. The photon detector supports pixel-selection configurability which may improve overall SNR and also potentially generate images for different analyses. This work has contributed to the future research of system-level integration of a pixellated solid-state detector for secondary electron detection in the scanning electron microscope. PMID:23553907

  5. FITPix — fast interface for Timepix pixel detectors

    NASA Astrophysics Data System (ADS)

    Kraus, V.; Holik, M.; Jakubek, J.; Kroupa, M.; Soukup, P.; Vykydal, Z.

    2011-01-01

    The semiconductor pixel detector Timepix contains an array of 256 × 256 square pixels with pitch 55 μm. In addition to high spatial granularity the single quantum counting detector Timepix can provide also energy or time information in each pixel. This device is a powerful tool for radiation and particle detection, imaging and tracking. A new readout interface for silicon pixel detectors of the Medipix family has been developed in our group in order to provide a higher frame rate and enhanced flexibility of operation. The interface consists of a field programmable gate array, a USB 2.0 interface chip, DAC, ADC and a circuit which generates bias voltage for the sensor. The main control system is placed in the FPGA circuit which fully controls the Timepix device. This approach offers an easy way how to include new functionality and extended operation. The interface for Timepix supports all operation modes of the detector (counting, TOT, timing). The FITPix is a successor of the USB 1.22 Interface and the electronic readout is built with the latest available components, which allows achieving up to 90 frames per second with a single detector. The frame rate is about 20 times faster compared to the previous system while it maintains all same capabilities supported. In addition FITPix newly enables an adjustable clock frequency and hardware triggering which is a useful tool when there is the need for synchronized operation of multiple devices. Three modes of hardware trigger have been implemented: hardware trigger which starts the measurement, hardware trigger which terminates the measurement and hardware trigger which controls measurement fully. The entire system is fully powered through the USB bus. FITPix supports also readout from several detectors in chain in which case just an external power source is required. FITPix is a fully flexible device and the user needs no other equipment. FITPix combines high performance and mobility and it opens new fields of

  6. A semiconductor radiation imaging pixel detector for space radiation dosimetry.

    PubMed

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented. PMID:26256630

  7. A semiconductor radiation imaging pixel detector for space radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

    2015-07-01

    Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented.

  8. Imaging performance of the hybrid pixel detectors XPAD3-S

    NASA Astrophysics Data System (ADS)

    Brunner, F. Cassol; Clemens, J. C.; Hemmer, C.; Morel, C.

    2009-03-01

    Hybrid pixel detectors, originally developed for tracking particles in high-energy physics experiments, have recently been used in material sciences and macromolecular crystallography. Their capability to count single photons and to apply a threshold on the photon energy suggests that they could be optimal digital x-ray detectors in low energy beams such as for small animal computed tomography (CT). To investigate this issue, we have studied the imaging performance of photon counting hybrid pixel detectors based on the XPAD3-S chip. Two detectors are considered, connected either to a Si or to a CdTe sensor, the latter being of interest for its higher efficiency. Both a standard 'International Electrotechnical Commission' (IEC) mammography beam and a beam used for mouse CT results published in the literature are employed. The detector stability, linearity and noise are investigated as a function of the dose for several imaging exposures (~0.1-400 µGy). The perfect linearity of both detectors is confirmed, but an increase in internal noise for counting statistics higher than ~5000 photons has been found, corresponding to exposures above ~110 µGy and ~50 µGy for the Si and CdTe sensors, respectively. The noise power spectrum (NPS), the modulation transfer function (MTF) and the detective quantum efficiency (DQE) are then measured for two energy threshold configurations (5 keV and 18 keV) and three doses (~3, 30 and 300 µGy), in order to obtain a complete estimation of the detector performances. In general, the CdTe sensor shows a clear superiority with a maximal DQE(0) of ~1, thanks to its high efficiency (~100%). The DQE of the Si sensor is more dependent on the radiation quality, due to the energy dependence of its efficiency its maximum is ~0.4 with respect to the softer radiation. Finally, we compare the XPAD3-S DQE with published curves of other digital devices in a similar radiation condition. The XPAD3-S/CdTe detector appears to be the best with the highest

  9. Position-Sensitive Nuclear Spectroscopy with Pixel Detectors

    SciTech Connect

    Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav

    2007-10-26

    State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

  10. Monolithic pixel detectors in a deep submicron SOI process

    SciTech Connect

    Deptuch, Grzegorz; /Fermilab

    2009-10-01

    A compact charge-signal processing chain, composed of a two-stage semi-gaussian preamplifier-signal shaping filter, a discriminator and a binary counter, implemented in a prototype pixel detector using 0.20 {micro}m CMOS Silicon on Insulator process, is presented. The gain of the analog chain was measured 0.76 V/fC at the signal peaking time about 300 ns and the equivalent noise charge referred to the input of 80 e{sup -1}.

  11. Development of a cadmium telluride pixel detector for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Miyasaka, Hiromasa; Harrison, Fiona A.; Cook, Walter R.; Mao, Peter H.; Rana, Vikram R.; Ishikawa, Shin-Nosuke; Ushio, Masayoshi; Aono, Hiroyuki; Watanabe, Shin; Sato, Goro; Kokubun, Motohide; Takahashi, Tadayuki

    2009-08-01

    We are developing imaging Cadmium Telluride (CdTe) pixel detectors optimized for astrophysical hard X-ray applications. Our hybrid detector consist of a CdTe crystal 1mm thick and 2cm × 2cm in area with segmented anode contacts directly bonded to a custom low-noise application specific integrated circuit (ASIC). The CdTe sensor, fabricated by ACRORAD (Okinawa, Japan), has Schottky blocking contacts on a 605 micron pitch in a 32 × 32 array, providing low leakage current and enabling readout of the anode side. The detector is bonded using epoxy-gold stud interconnects to a custom low noise, low power ASIC circuit developed by Caltech's Space Radiation Laboratory. We have achieved very good energy resolution over a wide energy range (0.62keV FWHM @ 60keV, 10.8keV FWHM @ 662keV). We observe polarization effects at room temperature, but they are suppressed if we operate the detector at or below 0°C degree. These detectors have potential application for future missions such as the International X-ray Observatory (IXO).

  12. Simulation of the dynamic inefficiency of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Bartók, M.

    2015-05-01

    The Pixel Detector is the innermost part of the CMS Tracker. It therefore has to prevail in the harshest environment in terms of particle fluence and radiation. There are several mechanisms that may decrease the efficiency of the detector. These are mainly caused by data acquisition (DAQ) problems and/or Single Event Upsets (SEU). Any remaining efficiency loss is referred to as the dynamic inefficiency. It is caused by various mechanisms inside the Readout Chip (ROC) and depends strongly on the data occupancy. In the 2012 data, at high values of instantaneous luminosity the inefficiency reached 2% (in the region closest to the interaction point) which is not negligible. In the 2015 run higher instantaneous luminosity is expected, which will result in lower efficiencies; therefore this effect needs to be understood and simulated. A data-driven method has been developed to simulate dynamic inefficiency, which has been shown to successfully simulate the effects.

  13. The pixel detector for the CMS phase-II upgrade

    NASA Astrophysics Data System (ADS)

    Dinardo, M. E.

    2015-04-01

    The high luminosity phase of the Large Hadron Collider (HL-LHC) requires a major pixel detector R&D effort to develop both readout chip and sensor that are capable to withstand unprecedented extremely high radiation. The target integrated luminosity of 3000 fb-1, that the HL-LHC is expected to deliver over about 10 years of operation, translates into a hadron fluence of 2×1016 1 MeV eq.n. / cm2, or equivalently 10 MGy of radiation dose in silicon, at about 3 cm from the interaction region where the first layer of the pixel detector could be located. The CMS collaboration has undertaken two baseline sensor R&D programs on thin n-on-p planar and 3D silicon sensor technologies. Together with the ATLAS collaboration it has also been established a common R&D effort for the development of the readout chip in the 65 nm CMOS technology. Status, progresses, and prospects of the CMS R&D effort are presented and discussed in this article.

  14. Charge amplitude distribution of the Gossip gaseous pixel detector

    NASA Astrophysics Data System (ADS)

    Blanco Carballo, V. M.; Chefdeville, M.; Colas, P.; Giomataris, Y.; van der Graaf, H.; Gromov, V.; Hartjes, F.; Kluit, R.; Koffeman, E.; Salm, C.; Schmitz, J.; Smits, S. M.; Timmermans, J.; Visschers, J. L.

    2007-12-01

    The Gossip gaseous pixel detector is being developed for the detection of charged particles in extreme high radiation environments as foreseen close to the interaction point of the proposed super LHC. The detecting medium is a thin layer of gas. Because of the low density of this medium, only a few primary electron/ion pairs are created by the traversing particle. To get a detectable signal, the electrons drift towards a perforated metal foil (Micromegas) whereafter they are multiplied in a gas avalanche to provide a detectable signal. The gas avalanche occurs in the high field between the Micromegas and the pixel readout chip (ROC). Compared to a silicon pixel detector, Gossip features a low material budget and a low cooling power. An experiment using X-rays has indicated a possible high radiation tolerance exceeding 10 16 hadrons/cm 2. The amplified charge signal has a broad amplitude distribution due to the limited statistics of the primary ionization and the statistical variation of the gas amplification. Therefore, some degree of inefficiency is inevitable. This study presents experimental results on the charge amplitude distribution for CO 2/DME (dimethyl-ether) and Ar/iC 4H 10 mixtures. The measured curves were fitted with the outcome of a theoretical model. In the model, the physical Landau distribution is approximated by a Poisson distribution that is convoluted with the variation of the gas gain and the electronic noise. The value for the fraction of pedestal events is used for a direct calculation of the cluster density. For some gases, the measured cluster density is considerably lower than given in literature.

  15. A germanium hybrid pixel detector with 55μm pixel size and 65,000 channels

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Struth, B.; Hirsemann, H.; Sarajlic, M.; Smoljanin, S.; Zuvic, M.; Lampert, M. O.; Fritzsch, T.; Rothermund, M.; Graafsma, H.

    2014-12-01

    Hybrid pixel semiconductor detectors provide high performance through a combination of direct detection, a relatively small pixel size, fast readout and sophisticated signal processing circuitry in each pixel. For X-ray detection above 20 keV, high-Z sensor layers rather than silicon are needed to achieve high quantum efficiency, but many high-Z materials such as GaAs and CdTe often suffer from poor material properties or nonuniformities. Germanium is available in large wafers of extremely high quality, making it an appealing option for high-performance hybrid pixel X-ray detectors, but suitable technologies for finely pixelating and bump-bonding germanium have not previously been available. A finely-pixelated germanium photodiode sensor with a 256 by 256 array of 55μm pixels has been produced. The sensor has an n-on-p structure, with 700μm thickness. Using a low-temperature indium bump process, this sensor has been bonded to the Medipix3RX photoncounting readout chip. Tests with the LAMBDA readout system have shown that the detector works successfully, with a high bond yield and higher image uniformity than comparable high-Z systems. During cooling, the system is functional around -80°C (with warmer temperatures resulting in excessive leakage current), with -100°C sufficient for good performance.

  16. Capacitively coupled hybrid pixel assemblies for the CLIC vertex detector

    NASA Astrophysics Data System (ADS)

    Tehrani, N. Alipour; Arfaoui, S.; Benoit, M.; Dannheim, D.; Dette, K.; Hynds, D.; Kulis, S.; Perić, I.; Petrič, M.; Redford, S.; Sicking, E.; Valerio, P.

    2016-07-01

    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, where efficiencies of greater than 99% have been achieved at -60 V substrate bias, with a single hit resolution of 6.1 μm . Pixel cross-coupling results are also presented, showing the sensitivity to placement precision and planarity of the glue layer.

  17. Multilayer fluorescence imaging on a single-pixel detector.

    PubMed

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-07-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect. PMID:27446679

  18. Multilayer fluorescence imaging on a single-pixel detector

    PubMed Central

    Guo, Kaikai; Jiang, Shaowei; Zheng, Guoan

    2016-01-01

    A critical challenge for fluorescence imaging is the loss of high frequency components in the detection path. Such a loss can be related to the limited numerical aperture of the detection optics, aberrations of the lens, and tissue turbidity. In this paper, we report an imaging scheme that integrates multilayer sample modeling, ptychography-inspired recovery procedures, and lensless single-pixel detection to tackle this challenge. In the reported scheme, we directly placed a 3D sample on top of a single-pixel detector. We then used a known mask to generate speckle patterns in 3D and scanned this known mask to different positions for sample illumination. The sample was then modeled as multiple layers and the captured 1D fluorescence signals were used to recover multiple sample images along the z axis. The reported scheme may find applications in 3D fluorescence sectioning, time-resolved and spectrum-resolved imaging. It may also find applications in deep-tissue fluorescence imaging using the memory effect.

  19. A generic readout environment for prototype pixel detectors

    NASA Astrophysics Data System (ADS)

    Turqueti, Marcos; Rivera, Ryan; Prosser, Alan; Kwan, Simon

    2010-11-01

    Pixel detectors for experimental particle physics research have been implemented with a variety of readout formats and potentially generate massive amounts of data. Examples include the PSI46 device for the Compact Muon Solenoid (CMS) experiment which implements an analog readout, the Fermilab FPIX2.1 device with a digital readout, and the Fermilab Vertically Integrated Pixel device. The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory has developed a data acquisition system flexible and powerful enough to meet the various needs of these devices to support laboratory test bench as well as test beam applications. The system is called CAPTAN (Compact And Programmable daTa Acquisition Node) and is characterized by its flexibility, versatility and scalability by virtue of several key architectural features. These include a vertical bus that permits the user to stack multiple boards, a gigabit Ethernet link that permits high speed communications to the system and a core group of boards that provide specific processing and readout capabilities for the system. System software based on distributed computing techniques supports an expandable network of CAPTANs. In this paper, we describe the system architecture and give an overview of its capabilities.

  20. Towards a new generation of pixel detector readout chips

    NASA Astrophysics Data System (ADS)

    Campbell, M.; Alozy, J.; Ballabriga, R.; Frojdh, E.; Heijne, E.; Llopart, X.; Poikela, T.; Tlustos, L.; Valerio, P.; Wong, W.

    2016-01-01

    The Medipix3 Collaboration has broken new ground in spectroscopic X-ray imaging and in single particle detection and tracking. This paper will review briefly the performance and limitations of the present generation of pixel detector readout chips developed by the Collaboration. Through Silicon Via technology has the potential to provide a significant improvement in the tile-ability and more flexibility in the choice of readout architecture. This has been explored in the context of 3 projects with CEA-LETI using Medipix3 and Timepix3 wafers. The next generation of chips will aim to provide improved spectroscopic imaging performance at rates compatible with human CT. It will also aim to provide full spectroscopic images with unprecedented energy and spatial resolution. Some of the opportunities and challenges posed by moving to a more dense CMOS process will be discussed.

  1. Development of a cylindrical tracking detector with multichannel scintillation fibers and pixelated photon detector readout

    NASA Astrophysics Data System (ADS)

    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 mm2, 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.

  2. High-speed readout of high-Z pixel detectors with the LAMBDA detector

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Smoljanin, S.; Sheviakov, I.; Xia, Q.; Rothkirch, A.; Yu, Y.; Struth, B.; Hirsemann, H.; Graafsma, H.

    2014-12-01

    High-frame-rate X-ray pixel detectors make it possible to perform time-resolved experiments at synchrotron beamlines, and to make better use of these sources by shortening experiment times. LAMBDA is a photon-counting hybrid pixel detector based on the Medipix3 chip, designed to combine a small pixel size of 55 μm, a large tileable module design, high speed, and compatibility with ``high-Z'' sensors for hard X-ray detection. This technical paper focuses on LAMBDA's high-speed-readout functionality, which allows a frame rate of 2000 frames per second with no deadtime between successive images. This takes advantage of the Medipix3 chip's ``continuous read-write'' function and highly parallelised readout. The readout electronics serialise this data and send it back to a server PC over two 10 Gigabit Ethernet links. The server PC controls the detector and receives, processes and stores the data using software designed for the Tango control system. As a demonstration of high-speed readout of a high-Z sensor, a GaAs LAMBDA detector was used to make a high-speed X-ray video of a computer fan.

  3. Characterization of Pixelated Cadmium-Zinc-Telluride Detectors for Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    Comparisons of charge sharing and charge loss measurements between two pixelated Cadmium-Zinc-Telluride (CdZnTe) detectors are discussed. These properties along with the detector geometry help to define the limiting energy resolution and spatial resolution of the detector in question. The first detector consists of a 1-mm-thick piece of CdZnTe sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). Signal readout is via discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). This crystal is bonded to a custom-built readout chip (ASIC) providing all front-end electronics to each of the 256 independent pixels. These detectors act as precursors to that which will be used at the focal plane of the High Energy Replicated Optics (HERO) telescope currently being developed at Marshall Space Flight Center. With a telescope focal length of 6 meters, the detector needs to have a spatial resolution of around 200 microns in order to take full advantage of the HERO angular resolution. We discuss to what degree charge sharing will degrade energy resolution but will improve our spatial resolution through position interpolation.

  4. Methodological Study of a Single Photon Counting Pixel Detector at SPring-8

    SciTech Connect

    Toyokawa, H.; Suzuki, M.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Huelsen, G.; Kraft, P.

    2007-01-19

    PILATUS (Pixel Apparatus for the SLS) is a challenging project to develop a large area single photon counting pixel detector for synchrotron radiation experiments. SPring-8 examined the PLATUS single module detectors in collaboration with the Paul Scherrer Institute. The PILATUS-II single module detector has a desired performance with almost zero defective pixels and a fast frame rate up to 100 Hz using a newly developed PCI readout system on a Linux-PC. The maximum counting rate achieves more than 2 x 106 X-rays/s/pixel.

  5. A Medium-Format, Mixed-Mode Pixel Array Detector for Kilohertz X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Tate, M. W.; Chamberlain, D.; Green, K. S.; Philipp, H. T.; Purohit, P.; Strohman, C.; Gruner, S. M.

    2013-03-01

    An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid detector is constructed from a 3-side buttable, 128×128 pixel module based upon the mixed-mode pixel array detector (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The chip uses a charge integrating front end for a high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing a digital overflow counter extends the per frame dynamic range to >4×107 x-rays/pixel. Results are shown from a base configuration of a 2×3 module array (256×384 pixels).

  6. Beam test results for the BTeV silicon pixel detector

    SciTech Connect

    Jeffrey A. Appel, G. Chiodini et al.

    2000-09-28

    The authors report the results of the BTeV silicon pixel detector tests carried out in the MTest beam at Fermilab in 1999--2000. The pixel detector spatial resolution has been studied as a function of track inclination, sensor bias, and readout threshold.

  7. Characterization of M-π-n CdTe pixel detectors coupled to HEXITEC readout chip

    NASA Astrophysics Data System (ADS)

    Veale, M. C.; Kalliopuska, J.; Pohjonen, H.; Andersson, H.; Nenonen, S.; Seller, P.; Wilson, M. D.

    2012-01-01

    Segmentation of the anode-side of an M-π-n CdTe diode, where the pn-junction is diffused into the detector bulk, produces large improvements in the spatial and energy resolution of CdTe pixel detectors. It has been shown that this fabrication technique produces very high inter-pixel resistance and low leakage currents are obtained by physical isolation of the pixels of M-π-n CdTe detectors. In this paper the results from M-π-n CdTe detectors stud bonded to a spectroscopic readout ASIC are reported. The CdTe pixel detectors have 250 μm pitch and an area of 5 × 5 mm2 with thicknesses of 1 and 2 mm. The polarization and energy resolution dependence of the M-π-n CdTe detectors as a function of detector thickness are discussed.

  8. Adhesive Testing for the BTeV Pixel Detector

    SciTech Connect

    Lei, C.M.; Kwan, Simon; Hicks, D.; Hahn, Eileen; Hoffman, Jay; Austin, Sharon; Jones, Renee; /Fermilab

    2005-12-01

    The basic unit of the BTeV pixel detector is a multi-chip module which is comprised of a silicon sensor module bump-bonded to a number of readout chips. The pixel module will then be glued to a high intensity interconnect (HDI) cable using electrically conductive adhesive, and then onto a substrate using another kind of adhesive with reasonable thermal conductivity. This report is mostly addressed to the need of the latter--the substrate adhesive. The aim of this technical note is to summarize the testing efforts and results of this substrate adhesive covering a period since 2001 till the end of 2004. The substrate will serve two purposes: mechanical support and cooling of the modules. Stresses and strains will be generated when there is a thermal change on the substrate. In addition, since there are many kinds of materials, with different coefficient of thermal expansion (CTE), being glued together to form the complete detector assembly, the substrate may get distorted due to the CTE mismatches. As stress is directly proportional to the material modulus, a significant amount of effort was concentrated in understanding the adhesive modulus. There are other constraints which need to be considered as well. For instance, the detector will be placed in a vacuum close to the beam, and it will be exposed to significant radiation during operation. As there are so many requirements on the adhesive, it is certainly not that easy to find one that meets all the demands. With a reasonable screening that the adhesive candidates being radiation hard and have low outgassing, searching for suitable adhesives was focused on those with low modulus. That is because (1) a mechanically reliable and fail-proof adhesive structure with low stress is needed, and (2) the leaking current characteristics of the modules will increase if mechanical stresses are too high. However, much of the technical information needed is usually not available from the vendor and therefore testing on our own

  9. Commissioning of the upgraded ATLAS Pixel Detector for Run2 at LHC

    NASA Astrophysics Data System (ADS)

    Dobos, Daniel

    2016-07-01

    The Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run-1 of LHC. Taking advantage of the long showdown, the detector was extracted from the experiment and brought to the surface, to equip it with new service quarter panels, to repair modules and to ease installation of the Insertable B-Layer, a fourth layer of pixel detectors, installed in May 2014 between the existing Pixel Detector and a new smaller radius beam-pipe at a radius of 3.3 cm. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. An overview of the refurbishing of the Pixel Detector and of the IBL project as well as early performance tests using cosmic rays and beam data will be presented.

  10. Small-Scale Readout System Prototype for the STAR PIXEL Detector

    SciTech Connect

    Szelezniak, Michal; Anderssen, Eric; Greiner, Leo; Matis, Howard; Ritter, Hans Georg; Stezelberger, Thorsten; Sun, Xiangming; Thomas, James; Vu, Chinh; Wieman, Howard

    2008-10-10

    Development and prototyping efforts directed towards construction of a new vertex detector for the STAR experiment at the RHIC accelerator at BNL are presented. This new detector will extend the physics range of STAR by allowing for precision measurements of yields and spectra of particles containing heavy quarks. The innermost central part of the new detector is a high resolution pixel-type detector (PIXEL). PIXEL requirements are discussed as well as a conceptual mechanical design, a sensor development path, and a detector readout architecture. Selected progress with sensor prototypes dedicated to the PIXEL detector is summarized and the approach chosen for the readout system architecture validated in tests of hardware prototypes is discussed.

  11. Modelling and 3D optimisation of CdTe pixels detector array geometry - Extension to small pixels

    NASA Astrophysics Data System (ADS)

    Zumbiehl, A.; Hage-Ali, M.; Fougeres, P.; Koebel, J. M.; Regal, R.; Rit, C.; Ayoub, M.; Siffert, P.

    2001-08-01

    CdTe and CdZnTe pixel detectors offer great interest for many applications, especially for medical and industrial imaging. Up to now, the material, generally, used and investigated for pixel arrays was CZT (Hamel et al., IEEE Trans. Nucl. Sci. 43 (3) (1996) 1422; Barrett et al., Phys. Rev. Lett. 75 (1) (1995) 156; Bennett et al., Nucl. Instr. and Meth. A 392 (1997) 260; Eskin et al., J. Appl. Phys. 85 (2) (1999) 647; Brunett et al., J. Appl. Phys. 86 (7) (1999) 3926; Luke, Nucl. Instr. and Meth. A 380 (1996) 232), but cadmium telluride can also be an appropriate choice, as shown here. However, we clearly demonstrate here that the optimal pixel configuration is highly dependent on the electrical transport properties of the material. Depending on the field of primary interest, either energy resolution or counting rate efficiency in the photopeak, the geometry for each case has to be optimised. For that purpose, we have developed a calculation of the signal induced onto the pixel. Two distinct parts are used: after showing our approach for the weighting potential calculation, we present our results performed by a "pseudo-Monte Carlo" simulation. Results are supported by a few experimental comparisons. We argue about the optimum sizes with clarifying the problems caused by too small and too large pixel sizes. The study field is chosen to be vast, i.e. pixel size to detector thickness ratios ( W/ L) of 1/8-1, and detector thickness of 1.0-8.0 mm. In addition, several electrical transport properties are used. Since efficiency is often of primary interest, thick detectors could be very attractive, which are shown to be really feasible even on CdTe.

  12. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Kato, Koji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2013-12-01

    An uncooled infrared (IR) focal plane array (FPA) with 23.5 μm pixel pitch has been successfully demonstrated and has found wide commercial applications in the areas of thermography, security cameras, and other applications. One of the key issues for uncooled IRFPA technology is to shrink the pixel pitch because the size of the pixel pitch determines the overall size of the FPA, which, in turn, determines the cost of the IR camera products. This paper proposes an innovative pixel structure with a diaphragm and beams placed in different levels to realize an uncooled IRFPA with smaller pixel pitch (≦17 μm). The upper level consists of a diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to be placed on the adjacent pixels. The test devices of this pixel design with 12, 15, and 17 μm pitch have been fabricated on the Si read-out integrated circuit (ROIC) of quarter video graphics array (QVGA) (320×240) with 23.5 μm pitch. Their performances are nearly equal to those of the IRFPA with 23.5 μm pitch. For example, a noise equivalent temperature difference of 12 μm pixel is 63.1 mK for F/1 optics with the thermal time constant of 14.5 ms. Then, the proposed structure is shown to be effective for the existing IRFPA with 23.5 μm pitch because of the improvements in IR sensitivity. Furthermore, the advanced pixel structure that has the beams composed of two levels are demonstrated to be realizable.

  13. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  14. Exploration of Pixelated detectors for double beta decay searches within the COBRA experiment

    NASA Astrophysics Data System (ADS)

    Schwenke, M.; Zuber, K.; Janutta, B.; He, Z.; Zeng, F.; Anton, G.; Michel, T.; Durst, J.; Lück, F.; Gleixner, T.; Gössling, C.; Schulz, O.; Köttig, T.; Krawczynski, H.; Martin, J.; Stekl, I.; Cermak, P.

    2011-09-01

    The aim of the COBRA experiment is the search for neutrinoless double beta decay events in Cadmium Zinc Telluride (CdZnTe) room temperature semiconductor detectors. The development of pixelated detectors provides the potential for clear event identification and thus major background reduction. The tracking option of a semiconductor is a unique approach in this field. For initial studies, several possible detector systems are considered with a special regard for low background applications: the large volume system Polaris with a pixelated CdZnTe sensor, Timepix detectors with Si and enriched CdTe sensor material and a CdZnTe pixel system developed at the Washington University in St. Louis, USA. For all detector systems first experimental background measurements taken at underground laboratories (Gran Sasso Underground Laboratory in Italy, LNGS and the Niederniveau Messlabor Felsenkeller in Dresden, Germany) and additionally for the Timepix detectors simulation results are presented.

  15. Defective pixel map creation based on wavelet analysis in digital radiography detectors

    NASA Astrophysics Data System (ADS)

    Park, Chun Joo; Lee, Hyoung Koo; Song, William Y.; Achterkirchen, Thorsten Graeve; Kim, Ho Kyung

    2011-04-01

    The application of digital radiography detectors has attracted increasing attention in both medicine and industry. Since the imaging detectors are fabricated by semiconductor manufacturing process over large areas, defective pixels in the detectors are unavoidable. Moreover, the radiation damage due to the routine use of the detectors progressively increases the density of defective pixels. In this study, we present a method of identifying defective pixels in digital radiography detectors based on wavelet analysis. Artifacts generated due to wavelet transformations have been prevented by an additional local threshold method. The proposed method was applied to a sample digital radiography and the result was promising. The proposed method uses a single pair of dark and white images and does not require them to be corrected in gain-and-offset properties. This method will be helpful for the reliable use of digital radiography detectors through the working lifetime.

  16. The pixel detector readout ASIC for the MicroVertex Detector of the PANDA experiment

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Calvo, D.; De Remigis, P.; Kugathasan, T.; Mignone, M.; Rivetti, A.; Toscano, L.; Wheadon, R.

    2013-08-01

    The silicon pixel detector of the PANDA experiment is characterized by both high track density and the absence of a hardware trigger signal, thus leading to a huge amount of data to be acquired and transmitted to the DAQ. In order to cope with such challenging requirements, an ASIC based custom solution for the electronic readout has been chosen. The ASIC, named ToPiX, will provide the time position of each hit and a measure of the charge released with the Time over Threshold (ToT) technique. A reduced scale prototype in a CMOS 0.13 μm technology has been designed and tested. The prototype includes four columns made of 128 pixel cells, four columns of 32 cells and the end of column readout with a 32 cells deep FIFO for each double column. Each cell embeds a charge amplifier with constant current feedback capacitor discharge, a comparator with per cell adjustable threshold, 12-bits leading and trailing edge register for time and ToT measurement and an 8 bits configuration register. All the readout logic has been SEU-hardened by design using either Hamming encoding or triple modular redundancy. The chip has been tested both electrically via a test pulse input and connected to a detector in a beam test.

  17. Characterization of edgeless pixel detectors coupled to Medipix2 readout chip

    NASA Astrophysics Data System (ADS)

    Kalliopuska, Juha; Tlustos, Lukas; Eränen, Simo; Virolainen, Tuula

    2011-08-01

    VTT has developed a straightforward and fast process to fabricate four-side buttable (edgeless) microstrip and pixel detectors on 6 in. (150 mm) wafers. The process relies on advanced ion implantation to activate the edges of the detector instead of using polysilicon. The article characterizes 150 μm thick n-on-n edgeless pixel detector prototypes with a dead layer at the edge below 1 μm. Electrical and radiation response characterization of 1.4×1.4 cm2 n-on-n edgeless detectors has been done by coupling them to the Medipix2 readout chips. The distance of the detector's physical edge from the pixels was either 20 or 50 μm. The leakage current of flip-chip bonded edgeless Medipix2 detector assembles were measured to be ˜90 nA/cm2 and no breakdown was observed below 110 V. Radiation response characterization includes X-ray tube and radiation source responses. The characterization results show that the detector's response at the pixels close to the physical edge of the detector depend dramatically on the pixel-to-edge distance.

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

    NASA Astrophysics Data System (ADS)

    Zang, A.; Anton, G.; 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.

    2015-04-01

    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 was carried out to use the Dosepix detector as a kVp-meter, that means to determine the applied acceleration voltage from measured X-ray tubes spectra.

  19. Imaging and spectroscopic performance studies of pixellated CdTe Timepix detector

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Astromskas, V.; Fröjdh, E.; Fröjdh, C.; Gimenez, E. N.; Marchal, J.; O'Shea, V.; Stewart, G.; Tartoni, N.; Wilhelm, H.; Wraight, K.; Zain, R. M.

    2012-01-01

    In this work the results on imaging and spectroscopic performances of 14 × 14 × 1 mm CdTe detectors with 55 × 55 μm and 110 × 110 μm pixel pitch bump-bonded to a Timepix chip are presented. The performance of the 110 × 110 μm pixel detector was evaluated at the extreme conditions beam line I15 of the Diamond Light Source. The energy of X-rays was set between 25 and 77 keV. The beam was collimated through the edge slits to 20 μm FWHM incident in the middle of the pixel. The detector was operated in the time-over-threshold mode, allowing direct energy measurement. Energy in the neighbouring pixels was summed for spectra reconstruction. Energy resolution at 77 keV was found to be ΔE/E = 3.9%. Comparative imaging and energy resolution studies were carried out between two pixel size detectors with a fluorescence target X-ray tube and radioactive sources. The 110 × 110 μm pixel detector exhibited systematically better energy resolution in comparison to 55 × 55 μm. An imaging performance of 55 × 55 μm pixellated CdTe detector was assessed using the Modulation Transfer Function (MTF) technique and compared to the larger pixel. A considerable degradation in MTF was observed for bias voltages below -300 V. Significant room for improvement of the detector performance was identified both for imaging and spectroscopy and is discussed.

  20. Beam test results of the BTeV silicon pixel detector

    SciTech Connect

    Gabriele Chiodini et al.

    2000-09-28

    The authors have described the results of the BTeV silicon pixel detector beam test. The pixel detectors under test used samples of the first two generations of Fermilab pixel readout chips, FPIX0 and FPIX1, (indium bump-bonded to ATLAS sensor prototypes). The spatial resolution achieved using analog charge information is excellent for a large range of track inclination. The resolution is still very good using only 2-bit charge information. A relatively small dependence of the resolution on bias voltage is observed. The resolution is observed to depend dramatically on the discriminator threshold, and it deteriorates rapidly for threshold above 4000e{sup {minus}}.

  1. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    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.

  2. Pixel detectors in double beta decay experiments, a new approach for background reduction

    NASA Astrophysics Data System (ADS)

    Jose, J. M.; Čermák, P.; Štekl, I.; Shitov, Yu. A.; Rukhadze, E. N.; Rukhadze, N. I.; Brudanin, V. B.; Fiederle, M.; Fauler, A.; Loaiza, P.

    2013-08-01

    Double beta decay (ββ) experiments are challenging frontiers in contemporary physics. These experiments have the potential to investigate more about neutrinos (eg. nature and mass). The main challenge for these experiments is the reduction of background. The group at IEAP, CTU in Prague is investigating a new approach using pixel detectors Timepix. Pixel detector offer background reduction capabilities with its ability to identify the particle interaction (from the 2D signature it generates). However, use of pixel detectors has some challenges such as the presence of readout electronics near the sensing medium and heat dissipation. Different aspects of pixel setup (identification of radio-impurities, selection of radio-pure materials) and proposed experimental setup are presented. Also, results of preliminary background measurements (performed on the surface and in the underground laboratories) using the prototype setups are presented.

  3. Si pixel detectors in the detection of EC/EC decay

    SciTech Connect

    Jose, J. M.; Čermák, P.; Fajt, L.; Štekl, I.; Rukhadze, N. I.; Shitov, Yu. A.

    2015-08-17

    The SPT collaboration has been investigating the applicability of pixel detectors in the detection of two neutrino double electron capture (2νEC/EC) in{sup 106}Cd. The collaboration has proposed a Silicon Pixel Telescope (SPT) where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. The Pixel detector gives spatial information along with energy of the particle, thus helps to identify and remove the background signals. Four units of SPT prototype (using 0.5 and 1 mm Si sensors) were fabricated and installed in the LSM underground laboratory, France. Recent progress in the SPT experiment and preliminary results from background measurements are presented.

  4. 4.3 μm quantum cascade detector in pixel configuration.

    PubMed

    Harrer, A; Schwarz, B; Schuler, S; Reininger, P; Wirthmüller, A; Detz, H; MacFarland, D; Zederbauer, T; Andrews, A M; Rothermund, M; Oppermann, H; Schrenk, W; Strasser, G

    2016-07-25

    We present the design simulation and characterization of a quantum cascade detector operating at 4.3μm wavelength. Array integration and packaging processes were investigated. The device operates in the 4.3μm CO2 absorption region and consists of 64 pixels. The detector is designed fully compatible to standard processing and material growth methods for scalability to large pixel counts. The detector design is optimized for a high device resistance at elevated temperatures. A QCD simulation model was enhanced for resistance and responsivity optimization. The substrate illuminated pixels utilize a two dimensional Au diffraction grating to couple the light to the active region. A single pixel responsivity of 16mA/W at room temperature with a specific detectivity D* of 5⋅107 cmHz/W was measured. PMID:27464155

  5. Progress in the use of pixel detectors in double beta decay experiment TGV

    SciTech Connect

    Jose, J. M. [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a Collaboration: TGV Collaboration

    2013-12-30

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in {sup 106}Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  6. Progress in the use of pixel detectors in double beta decay experiment TGV

    NASA Astrophysics Data System (ADS)

    Jose, J. M.; TGV Collaboration

    2013-12-01

    The TGV collaboration has been investigating two neutrino double electron capture (2νEC/EC) in 106Cd since 2000. The double beta experiments would answer some of the puzzling problems about neutrinos (e.g. nature and mass) but one of the main challenges is the background events. The collaboration is investigating the use of pixel detectors in such rare decay experiments. Pixel detector gives spatial information along with energy of the particle, thus provides useful information to reduce the background. The collaboration has proposed a Silicon Pixel Telescope (SPT) for the next generation experiment; where a pair of Si pixel detectors with enriched Cd foil in the middle forms the detection unit. A prototype unit of SPT has been constructed and results of preliminary background measurements performed on the surface and in the underground laboratories are presented.

  7. X-ray Characterization of a Multichannel Smart-Pixel Array Detector

    SciTech Connect

    Ross, Steve; Haji-Sheikh, Michael; Huntington, Andrew; Kline, David; Lee, Adam; Li, Yuelin; Rhee, Jehyuk; Tarpley, Mary; Walko, Donald A.; Westberg, Gregg; Williams, George; Zou, Haifeng; Landahl, Eric

    2016-01-01

    The Voxtel VX-798 is a prototype X-ray pixel array detector (PAD) featuring a silicon sensor photodiode array of 48 x 48 pixels, each 130 mu m x 130 mu m x 520 mu m thick, coupled to a CMOS readout application specific integrated circuit (ASIC). The first synchrotron X-ray characterization of this detector is presented, and its ability to selectively count individual X-rays within two independent arrival time windows, a programmable energy range, and localized to a single pixel is demonstrated. During our first trial run at Argonne National Laboratory's Advance Photon Source, the detector achieved a 60 ns gating time and 700 eV full width at half-maximum energy resolution in agreement with design parameters. Each pixel of the PAD holds two independent digital counters, and the discriminator for X-ray energy features both an upper and lower threshold to window the energy of interest discarding unwanted background. This smart-pixel technology allows energy and time resolution to be set and optimized in software. It is found that the detector linearity follows an isolated dead-time model, implying that megahertz count rates should be possible in each pixel. Measurement of the line and point spread functions showed negligible spatial blurring. When combined with the timing structure of the synchrotron storage ring, it is demonstrated that the area detector can perform both picosecond time-resolved X-ray diffraction and fluorescence spectroscopy measurements.

  8. X-ray characterization of a multichannel smart-pixel array detector.

    PubMed

    Ross, Steve; Haji-Sheikh, Michael; Huntington, Andrew; Kline, David; Lee, Adam; Li, Yuelin; Rhee, Jehyuk; Tarpley, Mary; Walko, Donald A; Westberg, Gregg; Williams, George; Zou, Haifeng; Landahl, Eric

    2016-01-01

    The Voxtel VX-798 is a prototype X-ray pixel array detector (PAD) featuring a silicon sensor photodiode array of 48 × 48 pixels, each 130 µm × 130 µm × 520 µm thick, coupled to a CMOS readout application specific integrated circuit (ASIC). The first synchrotron X-ray characterization of this detector is presented, and its ability to selectively count individual X-rays within two independent arrival time windows, a programmable energy range, and localized to a single pixel is demonstrated. During our first trial run at Argonne National Laboratory's Advance Photon Source, the detector achieved a 60 ns gating time and 700 eV full width at half-maximum energy resolution in agreement with design parameters. Each pixel of the PAD holds two independent digital counters, and the discriminator for X-ray energy features both an upper and lower threshold to window the energy of interest discarding unwanted background. This smart-pixel technology allows energy and time resolution to be set and optimized in software. It is found that the detector linearity follows an isolated dead-time model, implying that megahertz count rates should be possible in each pixel. Measurement of the line and point spread functions showed negligible spatial blurring. When combined with the timing structure of the synchrotron storage ring, it is demonstrated that the area detector can perform both picosecond time-resolved X-ray diffraction and fluorescence spectroscopy measurements. PMID:26698064

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

    PubMed Central

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

    2016-01-01

    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. PMID:26917125

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

    PubMed

    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. PMID:26917125

  11. High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy.

    PubMed

    Tate, Mark W; Purohit, Prafull; Chamberlain, Darol; Nguyen, Kayla X; Hovden, Robert; Chang, Celesta S; Deb, Pratiti; Turgut, Emrah; Heron, John T; Schlom, Darrell G; Ralph, Daniel C; Fuchs, Gregory D; Shanks, Katherine S; Philipp, Hugh T; Muller, David A; Gruner, Sol M

    2016-02-01

    We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition system, and preliminary results from experiments with 80-200 keV electron beams. PMID:26750260

  12. Phase 1 Upgrade of the CMS Pixel Detector: Module Assembly and Testing

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish

    2014-03-01

    The CMS pixel detector is the innermost component of the all-silicon tracking system located closest to the interaction point and thus operates in a high-occupancy/high-radiation environment created by particle collisions. The performance of the current pixel detector has been excellent during Run 1 of the LHC. However, the foreseen increases of the instantaneous and integrated luminosities at the LHC necessitate an upgrade of the pixel detector in order to maintain the excellent tracking and physics performance of the CMS detector. The new pixel detector is expected to be installed during the extended end-of-year shutdown in 2016/17. The main new features of the upgraded pixel detector would be ultra-light mechanical design with four barrel layers and three end-caps on either side of the interaction point, digital readout chip with higher rate capability and new cooling system. These and other design improvements, along with the current status on module assembly and testing, will be discussed.

  13. The Pixel Detector of the ATLAS experiment for LHC Run-2

    NASA Astrophysics Data System (ADS)

    Pernegger, H.

    2015-06-01

    The Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run-1 of LHC. Taking advantage of the long shutdown, the detector was extracted from the experiment and brought to surface, to equip it with new service quarter panels, to repair modules and to ease installation of the Insertable B-Layer (IBL). IBL is a fourth layer of pixel detectors, and has been installed in May 2014 between the existing Pixel Detector and a new smaller beam pipe at a radius of 3.3 cm. To cope with the high radiation and hit occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. Furthermore, the physics performance will be improved through the reduction of pixel size while, targeting for a low material budget, a new mechanical support using lightweight staves and a CO2 based cooling system have been adopted. An overview of the refurbishing of the Pixel Detector and of the IBL project as well as the experience in its construction will be presented, focusing on adopted technologies, module and staves production, qualification of assembly procedure, integration of staves around the beam pipe and commissioning of the detector.

  14. Search for new, long-lived, charged particles using ionization in the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Axen, Bradley; Atlas Collaboration

    2016-03-01

    Several extensions of the Standard Model predict the existence of charged, very massive, and long-lived particles. Because of their high masses these particles would propagate non-relativistically through the ATLAS pixel detector and are therefore be identifiable through a measurement of large specific energy loss. Measuring heavy, long-lived particles through their track parameters in the pixel detector allows sensitivity to particles with lifetimes in the nanosecond range and above. This search presents an inner detector driven method for identifying such particles in proton-proton collisions at 13 TeV with the 2015 dataset corresponding to an integrated luminosity of 3.5 pb-1.

  15. High efficiency neutron sensitive amorphous silicon pixel detectors

    SciTech Connect

    Mireshghi, A.; Cho, G.; Drewery, J.S.; Hong, W.S.; Jing, T.; Lee, H.; Kaplan, S.N.; Perez-Mendez, V.

    1993-11-01

    A multi-layer a-Si:H based thermal neutron detector was designed, fabricated and simulated by Monte Carlo method. The detector consists of two PECVD deposited a-Si:H pin detectors interfaced with coated layers of Gd, as a thermal neutron converter. Simulation results indicate that a detector consisting of 2 Gd films with thicknesses of 2 and 4 {mu}m, sandwiched properly with two layers of sufficiently thick ({approximately}30{mu}m) amorphous silicon diodes, has the optimum parameters. The detectors have an intrinsic efficiency of about 42% at a threshold setting of 7000 electrons, with an expected average signal size of {approximately}12000 electrons which is well above the noise. This efficiency will be further increased to nearly 63%, if we use Gd with 50% enrichment in {sup 157}Gd. We can fabricate position sensitive detectors with spatial resolution of 300 {mu}m with gamma sensitivity of {approximately}1 {times} 10{sup {minus}5}. These detectors are highly radiation resistant and are good candidates for use in various application, where high efficiency, high resolution, gamma insensitive position sensitive neutron detectors are needed.

  16. Pixel detectors for diffraction-limited storage rings

    PubMed Central

    Denes, Peter; Schmitt, Bernd

    2014-01-01

    Dramatic advances in synchrotron radiation sources produce ever-brighter beams of X-rays, but those advances can only be used if there is a corresponding improvement in X-ray detectors. With the advent of storage ring sources capable of being diffraction-limited (down to a certain wavelength), advances in detector speed, dynamic range and functionality is required. While many of these improvements in detector capabilities are being pursued now, the orders-of-magnitude increases in brightness of diffraction-limited storage ring sources will require challenging non-incremental advances in detectors. This article summarizes the current state of the art, developments underway worldwide, and challenges that diffraction-limited storage ring sources present for detectors. PMID:25177989

  17. DEPFET Active Pixel Detectors for a Future Linear e(+}e({-)) Collider

    NASA Astrophysics Data System (ADS)

    Alonso, O.; Casanova, R.; Dieguez, A.; Dingfelder, J.; Hemperek, T.; Kishishita, T.; Kleinohl, T.; Koch, M.; Kruger, H.; Lemarenko, M.; Lutticke, F.; Marinas, C.; Schnell, M.; Wermes, N.; Campbell, A.; Ferber, T.; Kleinwort, C.; Niebuhr, C.; Soloviev, Y.; Steder, M.; Volkenborn, R.; Yaschenko, S.; Fischer, P.; Kreidl, C.; Peric, I.; Knopf, J.; Ritzert, M.; Curras, E.; Lopez-Virto, A.; Moya, D.; Vila, I.; Boronat, M.; Esperante, D.; Fuster, J.; Garcia, I. Garcia; Lacasta, C.; Oyanguren, A.; Ruiz, P.; Timon, G.; Vos, M.; Gessler, T.; Kuhn, W.; Lange, S.; Munchow, D.; Spruck, B.; Frey, A.; Geisler, C.; Schwenker, B.; Wilk, F.; Barvich, T.; Heck, M.; Heindl, S.; Lutz, O.; Muller, Th.; Pulvermacher, C.; Simonis, H. J.; Weiler, T.; Krausser, T.; Lipsky, O.; Rummel, S.; Schieck, J.; Schluter, T.; Ackermann, K.; Andricek, L.; Chekelian, V.; Chobanova, V.; Dalseno, J.; Kiesling, C.; Koffmane, C.; Gioi, L. Li; Moll, A.; Moser, H. G.; Muller, F.; Nedelkovska, E.; Ninkovic, J.; Petrovics, S.; Prothmann, K.; Richter, R.; Ritter, A.; Ritter, M.; Simon, F.; Vanhoefer, P.; Wassatsch, A.; Dolezal, Z.; Drasal, Z.; Kodys, P.; Kvasnicka, P.; Scheirich, J.

    2013-04-01

    The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 $\\mathrm{\\mathbf{\\mu m}}$. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling and services. In this paper the status of DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear $\\mathbf{e^+ e^-}$ collider.

  18. Physics performance and upgrade for Run II of the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Miglioranzi, S.

    2015-05-01

    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 trajectories in the high radiation environment close to the collision region. The operation and performance of the pixel detector during the first years of LHC running are described. More than 96% of the detector modules were operational during this period, with an average intrinsic hit efficiency larger than 99%. The alignment of the detector was found to be stable at the few-micron level over long periods of time. Detector material description, tracking performances in Run I and expectations for the upcoming Run II are presented.

  19. Interconnect and bonding techniques for pixelated X-ray and gamma-ray detectors

    NASA Astrophysics Data System (ADS)

    Schneider, A.; Veale, M. C.; Duarte, D. D.; Bell, S. J.; Wilson, M. D.; Lipp, J. D.; Seller, P.

    2015-02-01

    In the last decade, the Detector Development Group at the Technology Department of the Science and Technology Facilities Council (STFC), U.K., established a variety of fabrication and bonding techniques to build pixelated X-ray and γ-ray detector systems such as the spectroscopic X-ray imaging detector HEXITEC [1]. The fabrication and bonding of such devices comprises a range of processes including material surface preparation, photolithography, stencil printing, flip-chip and wire bonding of detectors to application-specific integrated circuits (ASIC). This paper presents interconnect and bonding techniques used in the fabrication chain for pixelated detectors assembled at STFC. For this purpose, detector dies (~ 20× 20 mm2) of high quality, single crystal semiconductors, such as cadmium zinc telluride (CZT) are cut to the required thickness (up to 5mm). The die surfaces are lapped and polished to a mirror-finish and then individually processed by electroless gold deposition combined with photolithography to form 74× 74 arrays of 200 μ m × 200 μ m pixels with 250 μ m pitch. Owing to a lack of availability of CZT wafers, lithography is commonly carried out on individual detector dies which represents a significant technical challenge as the edge of the pixel array and the surrounding guard band lies close to the physical edge of the crystal. Further, such detector dies are flip-chip bonded to readout ASIC using low-temperature curing silver-loaded epoxy so that the stress between the bonded detector die and the ASIC is minimized. In addition, this reduces crystalline modifications of the detector die that occur at temperature greater than 150\\r{ }C and have adverse effects on the detector performance. To allow smaller pitch detectors to be bonded, STFC has also developed a compression cold-weld indium bump bonding technique utilising bumps formed by a photolithographic lift-off technique.

  20. Hard x-ray response of pixellated CdZnTe detectors

    SciTech Connect

    Abbene, L.; Caccia, S.; Bertuccio, G.

    2009-06-15

    In recent years, the development of cadmium zinc telluride (CdZnTe) detectors for x-ray and gamma ray spectrometry has grown rapidly. The good room temperature performance and the high spatial resolution of pixellated CdZnTe detectors make them very attractive in space-borne x-ray astronomy, mainly as focal plane detectors for the new generation of hard x-ray focusing telescopes. In this work, we investigated on the spectroscopic performance of two pixellated CdZnTe detectors coupled with a custom low noise and low power readout application specific integrated circuit (ASIC). The detectors (10x10x1 and 10x10x2 mm{sup 3} single crystals) have an anode layout based on an array of 256 pixels with a geometric pitch of 0.5 mm. The ASIC, fabricated in 0.8 mum BiCMOS technology, is equipped with eight independent channels (preamplifier and shaper) and characterized by low power consumption (0.5 mW/channel) and low noise (150-500 electrons rms). The spectroscopic results point out the good energy resolution of both detectors at room temperature [5.8% full width at half maximum (FWHM) at 59.5 keV for the 1 mm thick detector; 5.5% FWHM at 59.5 keV for the 2 mm thick detector) and low tailing in the measured spectra, confirming the single charge carrier sensing properties of the CdZnTe detectors equipped with a pixellated anode layout. Temperature measurements show optimum performance of the system (detector and electronics) at T=10 deg.C and performance degradation at lower temperatures. The detectors and the ASIC were developed by our collaboration as two small focal plane detector prototypes for hard x-ray multilayer telescopes operating in the 20-70 keV energy range.

  1. A new generation of small pixel pitch/SWaP cooled infrared detectors

    NASA Astrophysics Data System (ADS)

    Espuno, L.; Pacaud, O.; Reibel, Y.; Rubaldo, L.; Kerlain, A.; Péré-Laperne, N.; Dariel, A.; Roumegoux, J.; Brunner, A.; Kessler, A.; Gravrand, O.; Castelein, P.

    2015-10-01

    Following clear technological trends, the cooled IR detectors market is now in demand for smaller, more efficient and higher performance products. This demand pushes products developments towards constant innovations on detectors, read-out circuits, proximity electronics boards, and coolers. Sofradir was first to show a 10μm focal plane array (FPA) at DSS 2012, and announced the DAPHNIS 10μm product line back in 2014. This pixel pitch is a key enabler for infrared detectors with increased resolution. Sofradir recently achieved outstanding products demonstrations at this pixel pitch, which clearly demonstrate the benefits of adopting 10μm pixel pitch focal plane array-based detectors. Both HD and XGA Daphnis 10μm products also benefit from a global video datapath efficiency improvement by transitioning to digital video interfaces. Moreover, innovative smart pixels functionalities drastically increase product versatility. In addition to this strong push towards a higher pixels density, Sofradir acknowledges the need for smaller and lower power cooled infrared detector. Together with straightforward system interfaces and better overall performances, latest technological advances on SWAP-C (Size, Weight, Power and Cost) Sofradir products enable the advent of a new generation of high performance portable and agile systems (handheld thermal imagers, unmanned aerial vehicles, light gimbals etc...). This paper focuses on those features and performances that can make an actual difference in the field.

  2. The Pixel Detector of the ATLAS experiment for Run 2 of the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Oide, H.

    2014-12-01

    The Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run 1 of the LHC. Taking advantage of the long shutdown, the detector was extracted from the experiment and brought to surface in order to equip it with new service quarter panels, to repair modules, and to ease installation of the Insertable B-Layer (IBL). The IBL is the fourth layer of the Run 2 Pixel Detector, and it was installed at a radius of 3.3 cm in May 2014 between the existing Pixel Detector and the new smaller-radius beam pipe. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed. Furthermore, the physics performance is expected to improve through the reduction of pixel size. As well, targeting for a low material budget, a new mechanical support using lightweight staves and a CO2 based cooling system were adopted. An overview of the IBL project as well as the experience in its construction is presented, focusing on adopted technologies, module and staves production, qualification of assembly procedure, integration of staves around the beam pipe, and commissioning of the detector.

  3. Evaluation of a Wobbling Method Applied to Correcting Defective Pixels of CZT Detectors in SPECT Imaging

    PubMed Central

    Xie, Zhaoheng; Li, Suying; Yang, Kun; Xu, Baixuan; Ren, Qiushi

    2016-01-01

    In this paper, we propose a wobbling method to correct bad pixels in cadmium zinc telluride (CZT) detectors, using information of related images. We build up an automated device that realizes the wobbling correction for small animal Single Photon Emission Computed Tomography (SPECT) imaging. The wobbling correction method is applied to various constellations of defective pixels. The corrected images are compared with the results of conventional interpolation method, and the correction effectiveness is evaluated quantitatively using the factor of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In summary, the proposed wobbling method, equipped with the automatic mechanical system, provides a better image quality for correcting defective pixels, which could be used for all pixelated detectors for molecular imaging. PMID:27240368

  4. NIRSpec detectors: noise properties and the effect of signal dependent inter-pixel crosstalk

    NASA Astrophysics Data System (ADS)

    Giardino, Giovanna; Sirianni, Marco; Birkmann, Stephan M.; Rauscher, Bernard J.; Lindler, Don; Boeker, Torsten; Ferruit, Pierre; De Marchi, Guido; Stuhlinger, Martin; Jensen, Peter; Strada, Paolo

    2012-07-01

    NIRSpec (Near Infrared Spectrograph) is one of the four science instruments of the James Webb Space Telescope (JWST) and its focal plane consists of two HAWAII-2RG sensors operating in the wavelength range 0.6-5.0μm. As part of characterizing NIRSpec, we studied the noise properties of these detectors under dark and illuminated conditions. Under dark conditions, and as already known, 1/f noise in the detector system produces somewhat more noise than can be accounted for by a simple model that includes white read noise and shot noise on integrated charge. More surprisingly, at high flux, we observe significantly lower total noise levels than expected. We show this effect to be due to pixel-to-pixel correlations introduced by signal dependent inter-pixel crosstalk, with an inter-pixel coupling factor, α, that ranges from ~ 0.01 for zero signal to ~ 0.03 close to saturation.

  5. Evaluation of a Wobbling Method Applied to Correcting Defective Pixels of CZT Detectors in SPECT Imaging.

    PubMed

    Xie, Zhaoheng; Li, Suying; Yang, Kun; Xu, Baixuan; Ren, Qiushi

    2016-01-01

    In this paper, we propose a wobbling method to correct bad pixels in cadmium zinc telluride (CZT) detectors, using information of related images. We build up an automated device that realizes the wobbling correction for small animal Single Photon Emission Computed Tomography (SPECT) imaging. The wobbling correction method is applied to various constellations of defective pixels. The corrected images are compared with the results of conventional interpolation method, and the correction effectiveness is evaluated quantitatively using the factor of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In summary, the proposed wobbling method, equipped with the automatic mechanical system, provides a better image quality for correcting defective pixels, which could be used for all pixelated detectors for molecular imaging. PMID:27240368

  6. Charge Sharing and Charge Loss in a Cadmium-Zinc-Telluride Fine-Pixel Detector Array

    NASA Technical Reports Server (NTRS)

    Gaskin, J. A.; Sharma, D. P.; Ramsey, B. D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a Cadmium-Zinc-Telluride (CZT) multi-pixel detector is ideal for hard x-ray astrophysical observation. As part of on-going research at MSFC (Marshall Space Flight Center) to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750micron pitch), lmm 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 300micron pitch). Future work will enable us to compare the simulated results for the finer array to measured values.

  7. Imaging detector development for nuclear astrophysics using pixelated CdTe

    NASA Astrophysics Data System (ADS)

    Álvarez, J. M.; Gálvez, J. L.; Hernanz, M.; Isern, J.; Llopis, M.; Lozano, M.; Pellegrini, G.; Chmeissani, M.

    2010-11-01

    The concept of focusing telescopes in the energy range of lines of astrophysical interest (i.e., of energies around 1 MeV) should allow to reach unprecedented sensitivities, essential to perform detailed studies of cosmic explosions and cosmic accelerators. Our research and development activities aim to study a detector suited for the focal plane of a γ-ray telescope mission. A CdTe/CdZnTe detector operating at room temperature, that combines high detection efficiency with good spatial and spectral resolution is being studied in recent years as a focal plane detector, with the interesting option of also operating as a Compton telescope monitor. We present the current status of the design and development of a γ-ray imaging spectrometer in the MeV range, for nuclear astrophysics, consisting of a stack of CdTe pixel detectors with increasing thicknesses. We have developed an initial prototype based on CdTe ohmic detector. The detector has 11×11 pixels, with a pixel pitch of 1 mm and a thickness of 2 mm. Each pixel is stud bonded to a fanout board and routed to an front end ASIC to measure pulse height and rise time information for each incident γ-ray photon. First measurements of a 133Ba and 241Am source are reported here.

  8. Low-cost bump-bonding processes for high energy physics pixel detectors

    NASA Astrophysics Data System (ADS)

    Caselle, M.; Blank, T.; Colombo, F.; Dierlamm, A.; Husemann, U.; Kudella, S.; Weber, M.

    2016-01-01

    In the next generation of collider experiments detectors will be challenged by unprecedented particle fluxes. Thus large detector arrays of highly pixelated detectors with minimal dead area will be required at reasonable costs. Bump-bonding of pixel detectors has been shown to be a major cost-driver. KIT is one of five production centers of the CMS barrel pixel detector for the Phase I Upgrade. In this contribution the SnPb bump-bonding process and the production yield is reported. In parallel to the production of the new CMS pixel detector, several alternatives to the expensive photolithography electroplating/electroless metal deposition technologies are developing. Recent progress and challenges faced in the development of bump-bonding technology based on gold-stud bonding by thin (15 μm) gold wire is presented. This technique allows producing metal bumps with diameters down to 30 μm without using photolithography processes, which are typically required to provide suitable under bump metallization. The short setup time for the bumping process makes gold-stud bump-bonding highly attractive (and affordable) for the flip-chipping of single prototype ICs, which is the main limitation of the current photolithography processes.

  9. Novel module production methods for the CMS pixel detector, upgrade phase I

    NASA Astrophysics Data System (ADS)

    Blank, T.; Caselle, M.; Weber, M.; Kudella, S.; Colombo, F.; Hansen, K.; Arab, S.

    2015-02-01

    For the High-Luminosity upgrade of the LHC (HL-LHC), phase I, the CMS pixel detector needs to be replaced. In order to improve the tracking resolution even at high luminosity the pixel detector is upgraded by a fourth barrel layer. This paper describes the production process and results for the fourth barrel layer for the CMS silicon pixel detector, upgrade phase I. The additional barrel layer will be produced by KIT and DESY. Both research centers have commonly developed and investigated new production processes, including SAC solder bump jetting, gold stud bumping and "Precoat by Powder Processes" (PPS) to bump the sensor tiles and prepare them for the flip-chip process. First bare modules have been produced with the new digital ROC.

  10. Gas pixel detectors for high-sensitivity x-ray polarimetry

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

    We discuss a new class of Micro Pattern Gas Detectors, the Gas Pixel Detector (GPD), in which a complete integration between the gas amplification structure and the read-out electronics has been reached. An Application-Specific Integrated Circuit (ASIC) built in deep sub-micron technology has been developed to realize a monolithic device that is, at the same time, the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics. The CMOS chip has the top metal layer patterned in a matrix of 80 μm pitch hexagonal pixels, each of them directly connected to the underneath electronics chain which has been realized in the remaining five layers of the 0.35 μm VLSI technology. Results from tests of a first prototype of such detector with 2k pixels and a full scale version with 22k pixels are presented. The application of this device for Astronomical X-Ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation is shown. Results from a full MonteCarlo simulation for two astronomical sources, the Crab Nebula and the Hercules X1, are also reported.

  11. Beam test characterization of CMS silicon pixel detectors for the phase-1 upgrade

    NASA Astrophysics Data System (ADS)

    Korol, I.

    2015-10-01

    The Silicon Pixel Detector forms the innermost part of the CMS tracking system and is critical to track and vertex reconstruction. Being in close proximity to the beam interaction point, it is exposed to the highest radiation levels in the silicon tracker. In order to preserve the tracking performance with the LHC luminosity increase which is foreseen for the next years, the CMS collaboration has decided to build a new pixel detector with four barrel layers mounted around a reduced diameter beam pipe, as compared to the present three layer pixel detector in the central region. A new digital version of the front-end readout chip has been designed and tested; it has increased data buffering and readout link speed to maintain high efficiency at increasing occupancy. In addition, it offers lower charge thresholds that will improve the tracking efficiency and position resolution. Single chip modules have been evaluated in the DESY electron test beam in terms of charge collection, noise, tracking efficiency and position resolution before and after irradiation with 24 GeV protons from the CERN Proton Synchroton equivalent to the fluence expected after 500 fb-1 of integrated luminosity in the fourth layer of the pixel tracker. High efficiency and an excellent position resolution have been observed which are well maintained even after the proton irradiation. The results are well described by the CMS pixel detector simulation.

  12. A 2D smart pixel detector for time-resolved protein crystallography

    SciTech Connect

    Beuville, E.; Cork, C.; Earnest, T.

    1995-10-01

    A smart pixel detector is being developed for Time Resolved Crystallography for biological and material science applications. Using the Pixel detector presented here, the Laue method will enable the study of the evolution of structural changes that occur within the protein as a function of time. The x-ray pixellated detector is assembled to the integrated circuit through a bump bonding process. Within a pixel size of 150 x 150 {mu}m{sup 2}, a low noise preamplifier-shaper, a discriminator, a 3 bit counter and the readout logic are integrated. The readout, based on the Column Architecture principle, will accept hit rates above 5x10{sup 8}/cm{sup 2}/s with a maximum hit rate per pixel of 1 MHz. This detector will allow time resolved Laue crystallography to be performed in a frameless operation mode, without dead time. Target specifications, architecture, and preliminary results on the 8 x 8 front-end prototype and column readout are presented.

  13. Advanced Solid State Pixel Detectors for Future High Energy X-ray Missions

    NASA Astrophysics Data System (ADS)

    Harrison, Fiona

    We propose to advance the state of the art in solid state high energy X-ray pixel detectors for astrophysics. This program builds on advanced readout technology developed for suborbital and the NuSTAR space mission, and combines newly-developed CdTe PIN sensors and materials characterization techniques to achieve detectors broad band (1 - 200 keV), sub-keV energy resolution, and 300 micron spatial resolution. The low-noise readout technology will also be taken to the next generation with reduced pixel size, lower noise and significantly reduced dead time.

  14. A history of hybrid pixel detectors, from high energy physics to medical imaging

    NASA Astrophysics Data System (ADS)

    Delpierre, P.

    2014-05-01

    The aim of this paper is to describe the development of hybrid pixel detectors from the origin to the application on medical imaging. We are going to recall the need for fast 2D detectors in the high energy physics experiments and to follow the different pixel electronic circuits created to satisfy this demand. The adaptation of these circuits for X-rays will be presented as well as their industrialization. Today, a number of applications are open for these cameras, particularly for biomedical imaging applications. Some developments for clinical CT will also be shown.

  15. Test results on the silicon pixel detector for the TTF-FEL beam trajectory monitor

    NASA Astrophysics Data System (ADS)

    Hillert, S.; Ischebeck, R.; Müller, U. C.; Roth, S.; Hansen, K.; Holl, P.; Karstensen, S.; Kemmer, J.; Klanner, R.; Lechner, P.; Leenen, M.; Ng, J. S. T.; Schmüser, P.; Strüder, L.

    2001-02-01

    Test measurements on the silicon pixel detector for the beam trajectory monitor at the free-electron laser of the TESLA test facility are presented. To determine the electronic noise of the detector and the read-out electronics and to calibrate the signal amplitude of different pixels, the 6 keV photons of the manganese K α/K β line are used. Two different methods determine the spatial accuracy of the detector: in one setup a laser beam is focused to a straight line and moves across the pixel structure. In the other, the detector is scanned using a low-intensity electron beam of an electron microscope. Both methods show that the symmetry axis of the detector defines a straight line within 0.4 μm. The sensitivity of the detector to low-energy X-rays is measured using a vacuum ultraviolet beam at the synchrotron light source HASYLAB. Additionally, the electron microscope is used to study the radiation hardness of the detector.

  16. X-ray imaging using a 320 x 240 hybrid GaAs pixel detector

    SciTech Connect

    Irsigler, R.; Andersson, J.; Alverbro, J.

    1999-06-01

    The authors present room temperature measurements on 200 {micro}m thick GaAs pixel detectors, which were hybridized to silicon readout circuits. The whole detector array contains 320 x 240 square shaped pixel with a pitch of 38 {micro}m and is based on semi-insulating liquid-encapsulated Czochralski (LEC) GaAs material. After fabricating and dicing, the detector chips were indium bump flip chip bonded to CMOS readout circuits based on charge integration and finally evaluated. This readout chip was originally designed for the readout of flip chip bonded infrared detectors, but appears to be suitable for X-ray applications as well. A bias voltage between 50 V and 100 V was sufficient to operate the detector at room temperature. The detector array did respond to x-ray radiation by an increase in current due to production of electron hole pairs by the ionization processes. Images of various objects and slit patterns were acquired by using a standard X-ray source for dental imaging. The new X-ray hybrid detector was analyzed with respect to its imaging properties. Due to the high absorption coefficient for X-rays in GaAs and the small pixel size, the sensor shows a high modulation transfer function up to the Nyquist frequency.

  17. Charge Loss and Charge Sharing Measurements for Two Different Pixelated Cadmium-Zinc-Telluride Detectors

    NASA Technical Reports Server (NTRS)

    Gaskin, Jessica; Sharma, Dharma; Ramsey, Brian; Seller, Paul

    2003-01-01

    As part of ongoing research at Marshall Space Flight Center, Cadmium-Zinc- Telluride (CdZnTe) pixilated detectors are being developed for use at the focal plane of the High Energy Replicated Optics (HERO) telescope. HERO requires a 64x64 pixel array with a spatial resolution of around 200 microns (with a 6m focal length) and high energy resolution (< 2% at 60keV). We are currently testing smaller arrays as a necessary first step towards this goal. In this presentation, we compare charge sharing and charge loss measurements between two devices that differ both electronically and geometrically. The first device consists of a 1-mm-thick piece of CdZnTe that is sputtered with a 4x4 array of pixels with pixel pitch of 750 microns (inter-pixel gap is 100 microns). The signal is read out using discrete ultra-low-noise preamplifiers, one for each of the 16 pixels. The second detector consists of a 2-mm-thick piece of CdZnTe that is sputtered with a 16x16 array of pixels with a pixel pitch of 300 microns (inter-pixel gap is 50 microns). Instead of using discrete preamplifiers, the crystal is bonded to an ASIC that provides all of the front-end electronics to each of the 256 pixels. what degree the bias voltage (i.e. the electric field) and hence the drift and diffusion coefficients affect our measurements. Further, we compare the measured results with simulated results and discuss to

  18. Pixellated thallium bromide detectors for gamma-ray spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Onodera, T.; Hitomi, K.; Shoji, T.; Hiratate, Y.

    2004-06-01

    Recently, pixellated semiconductor detectors exhibit high-energy resolution, which have been studied actively and fabricated from CdTe, CZT and HgI 2. Thallium bromide (TlBr) is a compound semiconductor characterized with its high atomic numbers (Tl=81, Br=35) and high density (7.56 g/cm 3). Thus, TlBr exhibits higher photon stopping power than other semiconductor materials used for radiation detector fabrication such as CdTe, CZT and HgI 2. The wide band gap of TlBr (2.68 eV) permits the detectors low-noise operation at around room temperature. Our studies made an effort to fabricate pixellated TlBr detectors had sufficient detection efficiency and good charge collection efficiency. In this study, pixellated TlBr detectors were fabricated from the crystals purified by the multipass zone-refining method and grown by the horizontal traveling molten zone (TMZ) method. The TlBr detector has a continuous cathode over one crystal surface and 3×3 pixellated anodes (0.57×0.57 mm 2 each) surrounded by a guard ring on the opposite surface. The electrodes were realized by vacuum evaporation of palladium through a shadow mask. Typical thickness of the detector was 2 mm. Spectrometric performance of the TlBr detectors was tested by irradiating them with 241Am (59.5 keV), 57Co (122 keV) and 137Cs (662 keV) gamma-ray sources at temperature of -20°C. Energy resolutions (FWHM) were measured to be 4.0, 6.0 and 9.7 keV for 59.5, 122 and 662 keV gamma-rays, respectively.

  19. Low-flux measurements with Cornell's LCLS integrating pixel array detector

    NASA Astrophysics Data System (ADS)

    Philipp, Hugh T.; Tate, Mark W.; Gruner, Sol M.

    2011-11-01

    Next generation light sources are revolutionizing x-ray science by delivering ultra-intense, hard x-ray pulses many orders of magnitude brighter and shorter in duration than previously achievable. Maximizing the scientific potential of these light sources requires the development of suitable detectors. Experiments such as coherent x-ray imaging of single particles require detectors that can record extremely high instantaneous flux rates produced by femtosecond x-ray pulses (i.e. thousands of photons incident on a single pixel of an area detector in a few femtoseconds) while also being able to accurately distinguish single photon events so that many thousands of frames of data can be used to reconstruct extremely low flux information (e.g. less than 1/1000 photons per pixel per frame). This paper presents data from an integrating pixel array detector (PAD) possessing the ability to record high- and low-flux x-ray data at an X-ray Free Electron Laser (XFEL). Methods are presented to process extremely low-flux data (less than 1/10000 8-keV x-rays per pixel per frame) to accurately recover diffraction patterns from thousands of frames. The data were collected using a detector developed by Cornell for the Linac Coherent Light Source (LCLS) at SLAC National Lab. A copy of this detector was delivered to SLAC in the middle of 2008. The ASIC developed for this detector was used by SLAC as the basis for the CS-PAD (Cornell SLAC-PAD) being used on the Coherent X-ray Imaging beamline at the LCLS. These methods extend beyond XFEL applications because they allow for the suppression of dark accumulation noise which typically limits the low-flux capability of integrating detectors on conventional x-ray sources.

  20. Test of pixel detectors for laser-driven accelerated particle beams

    NASA Astrophysics Data System (ADS)

    Reinhardt, S.; Granja, C.; Krejci, F.; Assmann, W.

    2011-12-01

    Laser-driven accelerated (LDA) particle beams have due to the unique acceleration process very special properties. In particular they are created in ultra-short bunches of high intensity exceeding more than 107 \\frac{particles}{cm^{2} \\cdot ns} per bunch. Characterization of these beams is very limited with conventional particle detectors. Non-electronic detectors such as imaging plates or nuclear track detectors are, therefore, conventionally used at present. Moreover, all these detectors give only offline information about the particle pulse position and intensity as they require minutes to hours to be processed, calling for a new highly sensitive online device. Here, we present tests of different pixel detectors for real time detection of LDA ion pulses. Experiments have been performed at the Munich 14MV Tandem accelerator with 8-20 MeV protons in dc and pulsed beam, the latter producing comparable flux as a LDA ion pulse. For detection tests we chose the position-sensitive quantum-counting semiconductor pixel detector Timepix which also provides per-pixel energy- or time-sensitivity. Additionally other types of commercially available pixel detectors are being evaluated such as the RadEye™1, a large area (25 x 50 mm2) CMOS image sensor. All of these devices are able to resolve individual ions with high spatial- and energy-resolution down to the level of μm and tens of keV, respectively. Various beam delivering parameters of the accelerator were thus evaluated and verified. The different readout modes of the Timepix detector which is operated with an integrated USB-based readout interface allow online visualization of single and time-integrated events. Therefore Timepix offers the greatest potential in analyzing the beam parameters.

  1. 3 mega-pixel InSb detector with 10μm pitch

    NASA Astrophysics Data System (ADS)

    Gershon, G.; Albo, A.; Eylon, M.; Cohen, O.; Calahorra, Z.; Brumer, M.; Nitzani, M.; Avnon, E.; Aghion, Y.; Kogan, I.; Ilan, E.; Shkedy, L.

    2013-06-01

    SCD has developed a new 1920x1536 / 10 μm digital Infrared detector for the MWIR window named Blackbird. The Blackbird detector features a Focal Plane Array (FPA) that incorporates two technological building blocks developed over the past few years. The first one is a 10 μm InSb pixel based on the matured planar technology. The second building block is an innovative 10 μm ReadOut Integrated Circuit (ROIC) pixel. The InSb and the ROIC arrays are connected using Flip-Chip technology by means of indium bumps. The digital ROIC consists a matrix of 1920x1536 pixels and has an analog to digital (A/D) converter per-channel (total of 1920x2 A/Ds). It allows for full frame readout at a high frame rate of up to 120 Hz. Such an on-chip A/D conversion eliminates the need for several A/D converters with fairly high power consumption at the system level. The ROIC power consumption at maximum bandwidth is less than 400 mW. It features a wide range of pixel-level functionality such as several conversion gain options and a 2x2 pixel binning. The ROIC design makes use of the advanced and matured CMOS technology, 0.18 μm, which allows for high functionality and relatively low power consumption. The FPA is mounted on a Cold-Finger by a specially designed ceramic substrate. The whole assembly is housed in a stiffened Dewar that withstands harsh environmental conditions while minimizing the environment heat load contribution to the heat load of the detector. The design enables a 3-megapixel detector with overall low size, weight, and power (SWaP) with respect to comparable large format detectors. In this work we present in detail the characteristic performance of the new Blackbird detector.

  2. Physical characterization and performance comparison of active- and passive-pixel CMOS detectors for mammography.

    PubMed

    Elbakri, I A; McIntosh, B J; Rickey, D W

    2009-03-21

    We investigated the physical characteristics of two complementary metal oxide semiconductor (CMOS) mammography detectors. The detectors featured 14-bit image acquisition, 50 microm detector element (del) size and an active area of 5 cm x 5 cm. One detector was a passive-pixel sensor (PPS) with signal amplification performed by an array of amplifiers connected to dels via data lines. The other detector was an active-pixel sensor (APS) with signal amplification performed at each del. Passive-pixel designs have higher read noise due to data line capacitance, and the APS represents an attempt to improve the noise performance of this technology. We evaluated the detectors' resolution by measuring the modulation transfer function (MTF) using a tilted edge. We measured the noise power spectra (NPS) and detective quantum efficiencies (DQE) using mammographic beam conditions specified by the IEC 62220-1-2 standard. Our measurements showed the APS to have much higher gain, slightly higher MTF, and higher NPS. The MTF of both sensors approached 10% near the Nyquist limit. DQE values near dc frequency were in the range of 55-67%, with the APS sensor DQE lower than the PPS DQE for all frequencies. Our results show that lower read noise specifications in this case do not translate into gains in the imaging performance of the sensor. We postulate that the lower fill factor of the APS is a possible cause for this result. PMID:19242050

  3. Simulation of active-edge pixelated CdTe radiation detectors

    NASA Astrophysics Data System (ADS)

    Duarte, D. D.; Lipp, J. D.; Schneider, A.; Seller, P.; Veale, M. C.; Wilson, M. D.; Baker, M. A.; Sellin, P. J.

    2016-01-01

    The edge surfaces of single crystal CdTe play an important role in the electronic properties and performance of this material as an X-ray and γ-ray radiation detector. Edge effects have previously been reported to reduce the spectroscopic performance of the edge pixels in pixelated CdTe radiation detectors without guard bands. A novel Technology Computer Aided Design (TCAD) model based on experimental data has been developed to investigate these effects. The results presented in this paper show how localized low resistivity surfaces modify the internal electric field of CdTe creating potential wells. These result in a reduction of charge collection efficiency of the edge pixels, which compares well with experimental data.

  4. Study of indium and solder bumps for the BTeV Pixel Detector

    SciTech Connect

    Simon W Kwan et al.

    2003-11-05

    The pixel detector proposed for the BTeV experiment at the Fermilab Tevatron will use bump-bonding technology based on either Indium or Pb/Sn solder to connect the front-end readout chips to the silicon pixel sensors. We have studied the strength of the bumps by visual inspection of the bumps bonding silicon sensor modules to dummy chips made out of glass. The studies were done before and after thermal cycles, exposed to intense irradiation, and with the assemblies glued to a graphite substrate. We have also carried out studies on effects of temperature changes on both types of bump bonds by observing the responses of single-chip pixel detectors to an Sr{sup 90} source. We report the results from these studies and our plan to measure the effect of cryogenic temperatures on the bumps.

  5. A near-infrared 64-pixel superconducting nanowire single photon detector array with integrated multiplexed readout

    SciTech Connect

    Allman, M. S. Verma, V. B.; Stevens, M.; Gerrits, T.; Horansky, R. D.; Lita, A. E.; Mirin, R.; Nam, S. W.; Marsili, F.; Beyer, A.; Shaw, M. D.; Kumor, D.

    2015-05-11

    We demonstrate a 64-pixel free-space-coupled array of superconducting nanowire single photon detectors optimized for high detection efficiency in the near-infrared range. An integrated, readily scalable, multiplexed readout scheme is employed to reduce the number of readout lines to 16. The cryogenic, optical, and electronic packaging to read out the array as well as characterization measurements are discussed.

  6. The LAMBDA photon-counting pixel detector and high-Z sensor development

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Smoljanin, S.; Struth, B.; Hirsemann, H.; Fauler, A.; Fiederle, M.; Tolbanov, O.; Zarubin, A.; Tyazhev, A.; Shelkov, G.; Graafsma, H.

    2014-12-01

    Many X-ray experiments at third-generation synchrotrons benefit from using single-photon-counting detectors, due to their high signal-to-noise ratio and potential for high-speed measurements. LAMBDA (Large Area Medipix3-Based Detector Array) is a pixel detector system based on the Medipix3 readout chip. It combines the features of Medipix3, such as a small pixel size of 55 μm and flexible functionality, with a large tileable module design consisting of 12 chips (1536 × 512 pixels) and a high-speed readout system capable of running at 2000 frames per second. To enable high-speed experiments with hard X-rays, the LAMBDA system has been combined with different high-Z sensor materials. Room-temperature systems using GaAs and CdTe systems have been produced and tested with X-ray tubes and at synchrotron beamlines. Both detector materials show nonuniformities in their raw image response, but the pixel yield is high and the uniformity can be improved by flat-field correction, particularly in the case of GaAs. High-frame-rate experiments show that useful information can be gained on millisecond timescales in synchrotron experiments with these sensors.

  7. Simultaneous real-time visible and infrared video with single-pixel detectors.

    PubMed

    Edgar, Matthew P; Gibson, Graham M; Bowman, Richard W; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J; Welsh, Stephen S; Padgett, Miles J

    2015-01-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a 'single-pixel camera' to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics. PMID:26001092

  8. 640 x 480 pixel uncooled infrared FPA with SOI diode detectors

    NASA Astrophysics Data System (ADS)

    Ueno, Masashi; Kosasayama, Yasuhiro; Sugino, Takaki; Nakaki, Yoshiyuki; Fujii, Yoshio; Inoue, Hiromoto; Kama, Keisuke; Seto, Toshiki; Takeda, Munehisa; Kimata, Masafumi

    2005-05-01

    This paper describes the structure and performance of a 25-micron pitch 640 x 480 pixel uncooled infrared focal plane array (IR FPA) with silicon-on-insulator (SOI) diode detectors. The uncooled IR FPA is a thermal type FPA that has a temperature sensor of single crystal PN junction diodes formed in an SOI layer. In the conventional pixel structure, the temperature sensor and two support legs for thermal isolation are made in the lower level of the pixel, and an IR absorbing structure is made in the upper pixel level to cover almost the entire pixel area. The IR absorption utilizes IR reflections from the lower level. Since the reflection from the support leg portions is not perfect due to the slits in the metal reflector, the reflection becomes smaller as the support leg section increases in reduced pixel pitches. In order to achieve high thermal isolation and high IR absorption simultaneously, we have developed a new pixel structure that has an independent IR reflector between the lower and upper levels. The structure assures perfect IR reflection and thus improves IR absorption. The FPA shows a noise equivalent temperature difference (NETD) of 40 mK (f/1.0) and a responsivity non-uniformity of less than 0.9%. The good uniformity is due to the high uniformity of the electrical characteristics of SOI diodes made of single crystal silicon (Si). We have confirmed that the SOI diodes architecture is suitable for large format uncooled IR FPAs.

  9. Simultaneous real-time visible and infrared video with single-pixel detectors

    NASA Astrophysics Data System (ADS)

    Edgar, Matthew. P.; Gibson, Graham M.; Bowman, Richard W.; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J.; Welsh, Stephen S.; Padgett, Miles J.

    2015-05-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a ‘single-pixel camera’ to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics.

  10. Simultaneous real-time visible and infrared video with single-pixel detectors

    PubMed Central

    Edgar, Matthew. P.; Gibson, Graham M.; Bowman, Richard W.; Sun, Baoqing; Radwell, Neal; Mitchell, Kevin J.; Welsh, Stephen S.; Padgett, Miles J.

    2015-01-01

    Conventional cameras rely upon a pixelated sensor to provide spatial resolution. An alternative approach replaces the sensor with a pixelated transmission mask encoded with a series of binary patterns. Combining knowledge of the series of patterns and the associated filtered intensities, measured by single-pixel detectors, allows an image to be deduced through data inversion. In this work we extend the concept of a ‘single-pixel camera’ to provide continuous real-time video at 10 Hz , simultaneously in the visible and short-wave infrared, using an efficient computer algorithm. We demonstrate our camera for imaging through smoke, through a tinted screen, whilst performing compressive sampling and recovering high-resolution detail by arbitrarily controlling the pixel-binning of the masks. We anticipate real-time single-pixel video cameras to have considerable importance where pixelated sensors are limited, allowing for low-cost, non-visible imaging systems in applications such as night-vision, gas sensing and medical diagnostics. PMID:26001092

  11. Uncooled infrared detector with 12μm pixel pitch video graphics array

    NASA Astrophysics Data System (ADS)

    Endoh, Tsutomu; Tohyama, Shigeru; Yamazaki, Takao; Tanaka, Yutaka; Okuyama, Kuniyuki; Kurashina, Seiji; Miyoshi, Masaru; Katoh, Kouji; Yamamoto, Takashi; Okuda, Yuuhi; Sasaki, Tokuhito; Ishizaki, Haruo; Nakajima, Tomohiko; Shinoda, Kentaro; Tsuchiya, Tetsuo

    2013-06-01

    Uncooled infrared detectors with 12μm pixel pitch video graphics array (VGA) have been developed. To improve the signal to noise ratio (SNR) for 12μm pixel pitch, a highly sensitive bolometer material, an advanced pixel structure for thermal isolation and a newly designed read-out IC (ROIC) have been also developed. The bolometer material has been improved by using vanadium niobate. Over a wide range of temperature, temperature coefficient of resistance (TCR) is achieved higher level than -3.6%/K, which is 2 times higher than that for the conventional bolometer material. For thermal isolation, thermal conductance (Gth) value for the new pixel structure, fabricated by using triple level sacrificial layer process, is estimated to be 5nW/K, which is 1/5 times lower than that for the conventional pixel structure. On the other hand, since the imaging area is reduced by the pixel pitch, the uniformity of pixel can be improved. This enables to remove the non-uniformity correction (NUC) circuit in the ROIC. Removal of this circuit is effective for low power and low noise. This 12μm pixel pitch VGA detector is packaged in a compact (24 × 24 × 6.5 mm) and lightweight (11g) ceramic package. In addition, it has been incorporated in a newly developed prototype miniature imager. The miniature imager has dimension of 25(H) ×25(W) ×28(L) mm and weight of 30g. This imager is compact and small enough to fit in your hand. Hereafter, this imager is greatly expected to be applied to mobile systems.

  12. Optimal fine ϕ-slicing for single-photon-counting pixel detectors

    PubMed Central

    Mueller, Marcus; Wang, Meitian; Schulze-Briese, Clemens

    2012-01-01

    The data-collection parameters used in a macromolecular diffraction experiment have a strong impact on data quality. A careful choice of parameters leads to better data and can make the difference between success and failure in phasing attempts, and will also result in a more accurate atomic model. The selection of parameters has to account for the application of the data in various phasing methods or high-resolution refinement. Furthermore, experimental factors such as crystal characteristics, available experiment time and the properties of the X-ray source and detector have to be considered. For many years, CCD detectors have been the prevalent type of detectors used in macromolecular crystallography. Recently, hybrid pixel X-ray detectors that operate in single-photon-counting mode have become available. These detectors have fundamentally different characteristics compared with CCD detectors and different data-collection strategies should be applied. Fine ϕ-slicing is a strategy that is particularly well suited to hybrid pixel detectors because of the fast readout time and the absence of readout noise. A large number of data sets were systematically collected from crystals of four different proteins in order to investigate the benefit of fine ϕ-­slicing on data quality with a noise-free detector. The results show that fine ϕ-slicing can substantially improve scaling statistics and anomalous signal provided that the rotation angle is comparable to half the crystal mosaicity. PMID:22194332

  13. Test of a fine pitch SOI pixel detector with laser beam

    NASA Astrophysics Data System (ADS)

    Yi, Liu; Yunpeng, Lu; Xudong, Ju; Qun, Ou-Yang

    2016-01-01

    A silicon pixel detector with fine pitch size of 19 μm × 19 μm, developed based on SOI (silicon-on-insulator) technology, was tested under the illumination of infrared laser pulses. As an alternative method for particle beam tests, the laser pulses were tuned to very short duration and small transverse profile to simulate the tracks of MIPs (minimum ionization particles) in silicon. Hit cluster sizes were measured with focused laser pulses propagating through the SOI detector perpendicular to its surface and most of the induced charge was found to be collected inside the seed pixel. For the first time, the signal amplitude as a function of the applied bias voltage was measured for this SOI detector, deepening understanding of its depletion characteristics. Supported by National Natural Science Foundation of China (11375226)

  14. Analysis of full charge reconstruction algorithms for x-ray pixelated detectors

    SciTech Connect

    Baumbaugh, A.; Carini, G.; Deptuch, G.; Grybos, P.; Hoff, J.; Siddons, P., Maj.; Szczygiel, R.; Trimpl, M.; Yarema, R.; /Fermilab

    2011-11-01

    Existence of the natural diffusive spread of charge carriers on the course of their drift towards collecting electrodes in planar, segmented detectors results in a division of the original cloud of carriers between neighboring channels. This paper presents the analysis of algorithms, implementable with reasonable circuit resources, whose task is to prevent degradation of the detective quantum efficiency in highly granular, digital pixel detectors. The immediate motivation of the work is a photon science application requesting simultaneous timing spectroscopy and 2D position sensitivity. Leading edge discrimination, provided it can be freed from uncertainties associated with the charge sharing, is used for timing the events. Analyzed solutions can naturally be extended to the amplitude spectroscopy with pixel detectors.

  15. Analysis of Full Charge Reconstruction Algorithms for X-Ray Pixelated Detectors

    SciTech Connect

    Baumbaugh, A.; Carini, G.; Deptuch, G.; Grybos, P.; Hoff, J.; Siddons, P., Maj.; Szczygiel, R.; Trimpl, M.; Yarema, R.; /Fermilab

    2012-05-21

    Existence of the natural diffusive spread of charge carriers on the course of their drift towards collecting electrodes in planar, segmented detectors results in a division of the original cloud of carriers between neighboring channels. This paper presents the analysis of algorithms, implementable with reasonable circuit resources, whose task is to prevent degradation of the detective quantum efficiency in highly granular, digital pixel detectors. The immediate motivation of the work is a photon science application requesting simultaneous timing spectroscopy and 2D position sensitivity. Leading edge discrimination, provided it can be freed from uncertainties associated with the charge sharing, is used for timing the events. Analyzed solutions can naturally be extended to the amplitude spectroscopy with pixel detectors.

  16. Cat-eye effect target recognition with single-pixel detectors

    NASA Astrophysics Data System (ADS)

    Jian, Weijian; Li, Li; Zhang, Xiaoyue

    2015-12-01

    A prototype of cat-eye effect target recognition with single-pixel detectors is proposed. Based on the framework of compressive sensing, it is possible to recognize cat-eye effect targets by projecting a series of known random patterns and measuring the backscattered light with three single-pixel detectors in different locations. The prototype only requires simpler, less expensive detectors and extends well beyond the visible spectrum. The simulations are accomplished to evaluate the feasibility of the proposed prototype. We compared our results to that obtained from conventional cat-eye effect target recognition methods using area array sensor. The experimental results show that this method is feasible and superior to the conventional method in dynamic and complicated backgrounds.

  17. Test results of the Data Handling Processor for the DEPFET Pixel Vertex Detector

    NASA Astrophysics Data System (ADS)

    Lemarenko, M.; Hemperek, T.; Krüger, H.; Koch, M.; Lütticke, F.; Marinas, C.; Wermes, N.

    2013-01-01

    In the new Belle II detector, which is currently under construction at the SuperKEKB accelerator, a two layer pixel detector will be introduced to improve the vertex reconstruction in a ultra high luminosity environment. The pixel detector will be produced using the DEPFET technology. A new ASIC (Data Handling Processor or DHP) designed to steer the readout process, pre-process and compress the raw data has been developed. The DHP will be directly bump bonded to the balcony of the all-silicon DEPFET module. The current chip prototype has been produced in CMOS 90 nm. Its test results, including the data processing quality, the signal integrity of the gigabit transmission lines will be presented here. For the final chip, which will be produced using CMOS 65 nm, single event upset (SEU) cross sections were measured. An additional chip, containing memory blocks to be tested, was submitted and produced using this technology.

  18. A CMOS pixel sensor prototype for the outer layers of linear collider vertex detector

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    The International Linear Collider (ILC) expresses a stringent requirement for high precision vertex detectors (VXD). CMOS pixel sensors (CPS) have been considered as an option for the VXD of the International Large Detector (ILD), one of the detector concepts proposed for the ILC. MIMOSA-31 developed at IPHC-Strasbourg is the first CPS integrated with 4-bit column-level ADC for the outer layers of the VXD, adapted to an original concept minimizing the power consumption. It is composed of a matrix of 64 rows and 48 columns. The pixel concept combines in-pixel amplification with a correlated double sampling (CDS) operation in order to reduce the temporal noise and fixed pattern noise (FPN). At the bottom of the pixel array, each column is terminated with a self-triggered analog-to-digital converter (ADC). The ADC design was optimized for power saving at a sampling frequency of 6.25 MS/s. The prototype chip is fabricated in a 0.35 μm CMOS technology. This paper presents the details of the prototype chip and its test results.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  20. Counter Architectures for a Single Photon-Counting Pixel Detector such as Medipix3

    SciTech Connect

    Wong, W.; Ballabriga, R.; Campbell, M.; Llopart, X.; Tlustos, L.

    2007-11-26

    Medipix3 is a single photon-counting pixel readout chip whose new front-end architecture aims to eliminate the spectral distortion produced by charge diffusion in highly segmented semiconductor detectors. The chip requires area and power-efficient reconfigurable digital counters and shift registers that can be integrated with other photon-processing analog and digital circuits within the 55 {mu}mx55 {mu}m pixel area. This work proposes a configurable-depth, programmable mode digital counter for use in Medipix3.

  1. Accessing photon bunching with a photon number resolving multi-pixel detector.

    PubMed

    Kalashnikov, Dmitry A; Tan, Si Hui; Chekhova, Maria V; Krivitsky, Leonid A

    2011-05-01

    In quantum optics and its applications, there is an urgent demand for photon-number resolving detectors. Recently, there appeared multi-pixel counters (MPPC) that are able to distinguish between 1,2,..10 photons. At the same time, strong coupling between different pixels (crosstalk) hinders their photon-number resolution. In this work, we suggest a method for `filtering out' the crosstalk effect in the measurement of intensity correlation functions. The developed approach can be expanded to the analysis of higher-order intensity correlations by using just a single MPPC. PMID:21643191

  2. Development of a Prototype for the Fluorescence Detector Array of Single-Pixel Telescopes

    NASA Astrophysics Data System (ADS)

    Fujii, T.; Malacari, M.; Bertaina, M.; Casolino, M.; Dawson, B.; Jiang, J.; Matalon, A.; Matthews, J. N.; Motloch, P.; Privitera, P.; Takizawa, Y.; Yamazaki, K.

    We present a concept for large-area, low-cost detection of ultra-high energy cosmic rays (UHECR) with a Fluorescence detector Array of Single-pixel Telescopes (FAST), addressing the requirements for the next generation of UHECR experiments. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. We report preliminary results of a FAST prototype installed at the Telescope Array site, consisting of a single 200 mm photo-multiplier tube at the focal plane of a 1 m2 Fresnel lens system taken from the prototype of the JEM-EUSO experiment.

  3. Comparator threshold settings and the effective pixel width of the PICASSO detector

    NASA Astrophysics Data System (ADS)

    Lopez, F. C. M.; Rigon, L.; Fardin, L.; Arfelli, F.; Bergamaschi, A.; Dreossi, D.; Longo, M.; Schmitt, B.; Vallazza, E.; Longo, R.

    2014-05-01

    Charge sharing plays an important role in the performance of single-photon counting microstrip detectors, since the comparator threshold defines the effective pixel width. In this contribution, the PICASSO (Phase Imaging for Clinical Application with Silicon detector and Synchrotron radiatiOn) single-photon counting microstrip detector oriented in edge-on configuration has been used to study its spatial resolution as a function of the comparator threshold. The experiment was carried out with monochromatic x-rays at the SYRMEP beamline of the Elettra synchrotron radiation facility in Trieste (Italy). The Edge Spread Function (i.e. the integral of the Line spread Function, LSF) was measured by horizontally translating vertical slits from a bar-pattern test-object in front of the detector, at four different photon energies (19, 20, 22, and 25 keV) and for several different values of the comparator threshold. The effect of charge sharing between strips on the spatial resolution has been quantified by calculating the horizontal Modulation Transfer Function (MTF). Moreover, the composite LSF from neighboring pixels was obtained: this allowed estimating the optimal threshold for each photon energy by selecting the threshold at which the composite LSF would approach unity along the entire width of the pixel. The results show that at thresholds lower than half of the photon energy, charge sharing increases the effective pixel width, causing a drop of the MTF, and it is responsible for the appearance of peaks in the composite LSF. Conversely, at thresholds higher than half of the photon energy, the effective pixel width is reduced and the spatial resolution is increased, but the collection efficiency is compromised, as demonstrated by the presence of valleys in the composite LSF.

  4. MTF Issues in Small-Pixel-Pitch Planar Quantum IR Detectors

    NASA Astrophysics Data System (ADS)

    Gravrand, O.; Baier, N.; Ferron, A.; Rochette, F.; Berthoz, J.; Rubaldo, L.; Cluzel, R.

    2014-08-01

    The current trend in quantum infrared (IR) detector development is the design of very small-pixel-pitch large arrays. From the previous 30 μm pitch, the standard pixel pitch today is 15 μm and is expected to decrease to 12 μm in the next few years. Furthermore, focal-plane arrays (FPAs) with pixel pitch as small as 10 μm have been demonstrated. Such ultrasmall-pixel pitches are very small compared with the typical length ruling the electrical characteristics of the absorbing materials, namely the minority-carrier diffusion length. As an example, for low-doped n-type HgCdTe or InSb material, this diffusion length is on the order of 30 μm to 50 μm, i.e., three to five times the targeted pixel pitches. This has strong consequences for the modulation transfer function (MTF) of planar structures, where the lateral extension of the photodiode is limited by diffusion. For such aspect ratios, the self-confinement of neighboring diodes may not be efficient enough to maintain an optimal MTF. Therefore, this issue has to be addressed to take full advantage of the pixel pitch reduction in terms of image resolution. The aim of this work is to investigate the evolution of the MTF of HgCdTe and InSb FPAs when decreasing the pixel pitch below 15 μm. Both experimental measurements and finite-element simulations are used to discuss this issue. Different scenarios are compared, namely deep mesa etch between pixels, internal drift, surface recombination, and thin absorbing layers.

  5. Energy calibration of the pixels of spectral X-ray detectors.

    PubMed

    Panta, Raj Kumar; Walsh, Michael F; Bell, Stephen T; Anderson, Nigel G; Butler, Anthony P; Butler, Philip H

    2015-03-01

    The energy information acquired using spectral X-ray detectors allows noninvasive identification and characterization of chemical components of a material. To achieve this, it is important that the energy response of the detector is calibrated. The established techniques for energy calibration are not practical for routine use in pre-clinical or clinical research environment. This is due to the requirements of using monochromatic radiation sources such as synchrotron, radio-isotopes, and prohibitively long time needed to set up the equipment and make measurements. To address these limitations, we have developed an automated technique for calibrating the energy response of the pixels in a spectral X-ray detector that runs with minimal user intervention. This technique uses the X-ray tube voltage (kVp) as a reference energy, which is stepped through an energy range of interest. This technique locates the energy threshold where a pixel transitions from not-counting (off) to counting (on). Similarly, we have developed a technique for calibrating the energy response of individual pixels using X-ray fluorescence generated by metallic targets directly irradiated with polychromatic X-rays, and additionally γ-rays from (241)Am. This technique was used to measure the energy response of individual pixels in CdTe-Medipix3RX by characterizing noise performance, threshold dispersion, gain variation and spectral resolution. The comparison of these two techniques shows the energy difference of 1 keV at 59.5 keV which is less than the spectral resolution of the detector (full-width at half-maximum of 8 keV at 59.5 keV). Both techniques can be used as quality control tools in a pre-clinical multi-energy CT scanner using spectral X-ray detectors. PMID:25051546

  6. Influence of electromagnetic interference on the analog part of hybrid Pixel detectors

    NASA Astrophysics Data System (ADS)

    Holik, M.; Kraus, V.; Granja, C.; Jakubek, J.; Georgiev, V.; Hromadka, M.; Skala, J.; Kubik, Z.

    2011-12-01

    The analog signal from the sensor of hybrid semiconductor pixel detectors is prone to electro-magnetic interference. The study and diagnosis of induced and common electro-magnetic coupling between the analog part and digital part of these devices is required. The influence of electro-magnetic interference was tested on the setup with a pixel detector Timepix or Medipix and a FITPix read-out interface. Measurements were carried out of external as well as internal interference. We evaluated the influence of both sources of electro-magnetic interference to the noise recorded by pixels. We measured the local spatial intensity distribution and frequency spectrum of the electro-magnetic field originating inside the readout chip during its own operation. In context of this test we exposed the detector chip to a locally generated artificial electro-magnetic field evaluating its sensitivity to induced interference. Consequently, the whole setup of the detector and read-out interface was exposed to a distant source of electro-magnetic radiation, during which we tested efficiency of the electro-magnetic shielding of various arrangements. Further, tests measured the coupling over power supply lines. In particular, the noise generated by the operation of the detector itself was determined. In addition, the detector sensitivity to deliberately induced noise was evaluated. By means of these tests weak points of the setup sensitive to the intrusion of electro-magnetic interference are revealed. When locations of susceptible places are identified proper methods can be applied to increase immunity of the detector setup against the electro-magnetic interference. Experiences gained are planned to be used in development of the EMI shielded version of the FITPIX interface shielded to electro-magnetic interference.

  7. Comparison of CCD, CMOS and Hybrid Pixel x-ray detectors: detection principle and data quality

    NASA Astrophysics Data System (ADS)

    Allé, P.; Wenger, E.; Dahaoui, S.; Schaniel, D.; Lecomte, C.

    2016-06-01

    We compare, from a crystallographic point of view, the data quality obtained using laboratory x-ray diffractometers equipped with a Molybdenum micro-source using different detector types: CCD, CMOS and XPAD hybrid pixel. First we give an overview of the working principle of these different detector types with a focus on their principal differences and their impact on the data quality. Then, using the example of an organic crystal, a comparison between the detector systems concerning the raw data statistics, the refinement agreement factors, the deformation electron density maps, and the residual density after multipolar refinement is presented. It is found that the data quality obtained with the XPAD detector is the best, even though the detection efficiency at the Mo energy (17.5 keV) is only 37% due to the Si-sensor layer thickness of 300 μm. Finally, we discuss the latest x-ray detector developments with an emphasis on the sensor material, where replacing Si by another material such as GaAs would yield detection efficiencies close to 100%, up to energies of 40 keV for hybrid pixel detectors.

  8. Modeling and Analysis of Hybrid Pixel Detector Deficiencies for Scientific Applications

    SciTech Connect

    Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  9. Towards hybrid pixel detectors for energy-dispersive or soft X-ray photon science.

    PubMed

    Jungmann-Smith, J H; Bergamaschi, A; Brückner, M; Cartier, S; Dinapoli, R; Greiffenberg, D; Huthwelker, T; Maliakal, D; Mayilyan, D; Medjoubi, K; Mezza, D; Mozzanica, A; Ramilli, M; Ruder, Ch; Schädler, L; Schmitt, B; Shi, X; Tinti, G

    2016-03-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications at free-electron lasers and synchrotron light sources. The JUNGFRAU 0.4 prototype presented here is specifically geared towards low-noise performance and hence soft X-ray detection. The design, geometry and readout architecture of JUNGFRAU 0.4 correspond to those of other JUNGFRAU pixel detectors, which are charge-integrating detectors with 75 µm × 75 µm pixels. Main characteristics of JUNGFRAU 0.4 are its fixed gain and r.m.s. noise of as low as 27 e(-) electronic noise charge (<100 eV) with no active cooling. The 48 × 48 pixels JUNGFRAU 0.4 prototype can be combined with a charge-sharing suppression mask directly placed on the sensor, which keeps photons from hitting the charge-sharing regions of the pixels. The mask consists of a 150 µm tungsten sheet, in which 28 µm-diameter holes are laser-drilled. The mask is aligned with the pixels. The noise and gain characterization, and single-photon detection as low as 1.2 keV are shown. The performance of JUNGFRAU 0.4 without the mask and also in the charge-sharing suppression configuration (with the mask, with a `software mask' or a `cluster finding' algorithm) is tested, compared and evaluated, in particular with respect to the removal of the charge-sharing contribution in the spectra, the detection efficiency and the photon rate capability. Energy-dispersive and imaging experiments with fluorescence X-ray irradiation from an X-ray tube and a synchrotron light source are successfully demonstrated with an r.m.s. energy resolution of 20% (no mask) and 14% (with the mask) at 1.2 keV and of 5% at 13.3 keV. The performance evaluation of the JUNGFRAU 0.4 prototype suggests that this detection system could be the starting point for a future detector development effort for either applications in the soft X-ray energy regime or for an energy

  10. Modeling and analysis of hybrid pixel detector deficiencies for scientific applications

    NASA Astrophysics Data System (ADS)

    Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-01

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  11. Firmware development and testing of the ATLAS Pixel Detector / IBL ROD card

    NASA Astrophysics Data System (ADS)

    Gabrielli, A.; Backhaus, M.; Balbi, G.; Bindi, M.; Chen, S. P.; Falchieri, D.; Flick, T.; Hauck, S.; Hsu, S. C.; Kretz, M.; Kugel, A.; Lama, L.; Travaglini, R.; Wensing, M.

    2015-03-01

    The ATLAS Experiment is reworking and upgrading systems during the current LHC shut down. In particular, the Pixel detector has inserted an additional inner layer called the Insertable B-Layer (IBL). The Readout-Driver card (ROD), the Back-of-Crate card (BOC), and the S-Link together form the essential frontend data path of the IBL's off-detector DAQ system. The strategy for IBL ROD firmware development was three-fold: keeping as much of the Pixel ROD datapath firmware logic as possible, employing a complete new scheme of steering and calibration firmware, and designing the overall system to prepare for a future unified code version integrating IBL and Pixel layers. Essential features such as data formatting, frontend-specific error handling, and calibration are added to the ROD data path. An IBL DAQ test bench using a realistic front-end chip model was created to serve as an initial framework for full offline electronic system simulation. In this document, major firmware achievements concerning the IBL ROD data path implementation, test on the test bench and ROD prototypes, will be reported. Recent Pixel collaboration efforts focus on finalizing hardware and firmware tests for the IBL. The plan is to approach a complete IBL DAQ hardware-software installation by the end of 2014.

  12. A novel approach in the free-electron laser diagnosis based on a pixelated phosphor detector.

    PubMed

    Matruglio, Alessia; Dal Zilio, Simone; Sergo, Rudi; Mincigrucci, Riccardo; Svetina, Cristian; Principi, Emiliano; Mahne, Nicola; Raimondi, Lorenzo; Turchet, Alessio; Masciovecchio, Claudio; Lazzarino, Marco; Cautero, Giuseppe; Zangrando, Marco

    2016-01-01

    A new high-performance method for the free-electron laser (FEL) focused beam diagnosis has been successfully tested at the FERMI FEL in Trieste, Italy. The novel pixelated phosphor detector (PPD) consists of micrometric pixels produced by classical UV lithography and dry etching technique, fabricated on a silicon substrate, arranged in a hexagonal geometry and filled with suitable phosphors. It has been demonstrated that the overall resolution of the system has increased by reducing the diffusion of the light in the phosphors. Various types of PPD have been produced and tested, demonstrating a high resolution in the beam profile and the ability to measure the actual spot size shot-to-shot with an unprecedented resolution. For these reasons, the proposed detector could become a reference technique in the FEL diagnosis field. PMID:26698042

  13. Review of hybrid pixel detector readout ASICs for spectroscopic X-ray imaging

    NASA Astrophysics Data System (ADS)

    Ballabriga, R.; Alozy, J.; Campbell, M.; Frojdh, E.; Heijne, E. H. M.; Koenig, T.; Llopart, X.; Marchal, J.; Pennicard, D.; Poikela, T.; Tlustos, L.; Valerio, P.; Wong, W.; Zuber, M.

    2016-01-01

    Semiconductor detector readout chips with pulse processing electronics have made possible spectroscopic X-ray imaging, bringing an improvement in the overall image quality and, in the case of medical imaging, a reduction in the X-ray dose delivered to the patient. In this contribution we review the state of the art in semiconductor-detector readout ASICs for spectroscopic X-ray imaging with emphasis on hybrid pixel detector technology. We discuss how some of the key challenges of the technology (such as dealing with high fluxes, maintaining spectral fidelity, power consumption density) are addressed by the various ASICs. In order to understand the fundamental limits of the technology, the physics of the interaction of radiation with the semiconductor detector and the process of signal induction in the input electrodes of the readout circuit are described. Simulations of the process of signal induction are presented that reveal the importance of making use of the small pixel effect to minimize the impact of the slow motion of holes and hole trapping in the induced signal in high-Z sensor materials. This can contribute to preserve fidelity in the measured spectrum with relatively short values of the shaper peaking time. Simulations also show, on the other hand, the distortion in the energy spectrum due to charge sharing and fluorescence photons when the pixel pitch is decreased. However, using recent measurements from the Medipix3 ASIC, we demonstrate that the spectroscopic information contained in the incoming photon beam can be recovered by the implementation in hardware of an algorithm whereby the signal from a single photon is reconstructed and allocated to the pixel with the largest deposition.

  14. FITPix data preprocessing pipeline for the Timepix single particle pixel detector

    NASA Astrophysics Data System (ADS)

    Kraus, V.; Holik, M.; Jakubek, J.; Georgiev, V.

    2012-04-01

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

  15. Active pixels of transverse field detector based on a charge preamplifier

    NASA Astrophysics Data System (ADS)

    Langfelder, G.; Buffa, C.; Longoni, A. F.; Pelamatti, A.; Zaraga, F.

    2012-01-01

    The Transverse Field Detector (TFD), a filter-less and tunable color sensitive pixel, is based on the generation of specific electric field configurations within a depleted Silicon volume. Each field configuration determines a set of three or more spectral responses that can be used for direct color acquisition at each pixel position. In order to avoid unpredictable changes of the electric field configuration during the single image capture, a specific active pixel (AP) has been designed. In this AP the dark- and photo-generated charge is not integrated directly on the junction capacitance, but, for each color, it is integrated on the feedback capacitance of a single-transistor charge pre-amplifier. The AP further includes a bias transistor, a reset transistor and a follower. In this work the design of such a pixel is discussed and the experimental results obtained on a 2x2 matrix of these active pixels are analyzed in terms of spectral response, linearity, noise, dynamic range and repeatability.

  16. Fully 3D-Integrated Pixel Detectors for X-Rays

    SciTech Connect

    Deptuch, Grzegorz W.; Gabriella, Carini; Enquist, Paul; Grybos, Pawel; Holm, Scott; Lipton, Ronald; Maj, Piotr; Patti, Robert; Siddons, David Peter; Szczygiel, Robert; Yarema, Raymond

    2016-01-01

    The vertically integrated photon imaging chip (VIPIC1) pixel detector is a stack consisting of a 500-μm-thick silicon sensor, a two-tier 34-μm-thick integrated circuit, and a host printed circuit board (PCB). The integrated circuit tiers were bonded using the direct bonding technology with copper, and each tier features 1-μm-diameter through-silicon vias that were used for connections to the sensor on one side, and to the host PCB on the other side. The 80-μm-pixel-pitch sensor was the direct bonding technology with nickel bonded to the integrated circuit. The stack was mounted on the board using Sn–Pb balls placed on a 320-μm pitch, yielding an entirely wire-bond-less structure. The analog front-end features a pulse response peaking at below 250 ns, and the power consumption per pixel is 25 μW. We successful completed the 3-D integration and have reported here. Additionally, all pixels in the matrix of 64 × 64 pixels were responding on well-bonded devices. Correct operation of the sparsified readout, allowing a single 153-ns bunch timing resolution, was confirmed in the tests on a synchrotron beam of 10-keV X-rays. An equivalent noise charge of 36.2 e- rms and a conversion gain of 69.5 μV/e- with 2.6 e- rms and 2.7 μV/e- rms pixel-to-pixel variations, respectively, were measured.

  17. Development of high data readout rate pixel module and detector hybridization at Fermilab

    SciTech Connect

    Sergio Zimmermann et al.

    2001-03-20

    This paper describes the baseline design and a variation of the pixel module to handle the data rate required for the BTeV experiment at Fermilab. The present prototype has shown good electrical performance characteristics. Indium bump bonding is proven to be capable of successful fabrication at 50 micron pitch on real detectors. For solder bumps at 50 micron pitch, much better results have been obtained with the fluxless PADS processed detectors. The results are adequate for our needs and our tests have validated it as a viable technology.

  18. New Possibilities in Medical X-Ray Imaging with Photon Counting Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Durst, J.; Bartl, P.; Guni, E.; Haas, W.; Ritter, A.; Takoukam Talla, P.; Weber, T.; Michel, T.; Anton, G.

    2010-04-01

    The new generation of X-ray photon counting pixel detectors like the Medipix2 and the Medipix3 opens a new field of applications in medical X-ray imaging. These detectors work with one or more energy windows, which makes energy information available in addition to the intensity. A detailled understanding of the detector response of such detectors is important. Results will be presented for Si and CdTe as sensor material. With this knowledge two methods called spectrum reconstruction and material reconstruction can be applied to energy resolved images in absorption radiography and computed tomography. Another new application is the measurement of the phase information in computed tomography in addition to the absorption information. The potential of phase contrast imaging will be discussed.

  19. Towards Implementing Multi-Pixel Photon Counters as Light Detectors for Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Vasquez, Jaime; Saavedra, Arthur; Ramos, Roxana; Tavares, Pablo; Wade, Marcus; Fan, Sewan; Haag, Brooke

    2013-04-01

    There has been tremendous effort in recent years to implement multi-pixel photon counters (MPPC) in diverse areas of particle physics and positron emission tomography. The MPPC detectors possess certain favorable properties such as fast response time, high sensitivity to weak light signals, compact size, low operating voltage, and lower cost compared to photomultiplier tubes. However, constructing a working MPPC detector assembly is not a unique process; there are various working setups. In this poster, we present our particular experimental setup for a working MPPC detector assembly. In particular, we describe our efforts to implement the MPPC as a readout detector to be coupled to wavelength shifting fibers that are implanted within plastic scintillators for the measurement of cosmic rays.

  20. XNAP: a hybrid pixel detector with nanosecond resolution for time resolved synchrotron radiation studies

    NASA Astrophysics Data System (ADS)

    Fajardo, P.; Baron, A. Q. R.; Dautet, H.; Davies, M.; Fischer, P.; Göttlicher, P.; Graafsma, H.; Hervé, C.; Rüffer, R.; Thil, C.

    2013-03-01

    The XNAP collaboration is constructing a hybrid pixel X-ray detector based on a monolithic silicon avalanche photodiode (APD) sensor array aiming at applications in synchrotron radiation facilities. The 2D detector is capable of identifying which individual electron bunch produces each detected X-ray photon, even when the storage ring operates in multibunch filling modes. This instrument is intended to be used in X-ray Photon Correlation Spectroscopy and Nuclear Resonance experiments and serve as a demonstrator for various kind of time resolved diffraction and scattering applications as well as a very high count rate device. The detector is a 1 kilopixel device with 280 μm pitch that implements both counting mode up to MHz frame rates and event-by-event readout with sub-nanosecond time resolution. The paper describes the detector design and some results obtained with small 4×4 pixel prototypes that have been built and measured to make and validate the most critical choices for the final detector.

  1. Development of a readout technique for the high data rate BTeV pixel detector at Fermilab

    SciTech Connect

    Bradley K Hall et al.

    2001-11-05

    The pixel detector for the BTeV experiment at Fermilab provides digitized data from approximately 22 million silicon pixel channels. Portions of the detector are six millimeters from the beam providing a substantial hit rate and high radiation dose. The pixel detector data will be employed by the lowest level trigger system for track reconstruction every beam crossing. These requirements impose a considerable constraint on the readout scheme. This paper presents a readout technique that provides the bandwidth that is adequate for high hit rates, minimizes the number of radiation hard components, and satisfies all other design constraints.

  2. Development of thin pixel detectors on epitaxial silicon for HEP experiments

    NASA Astrophysics Data System (ADS)

    Boscardin, Maurizio; Calvo, Daniela; Giacomini, Gabriele; Wheadon, Richard; Ronchin, Sabina; Zorzi, Nicola

    2013-08-01

    The foreseen luminosity of the new experiments in High Energy Physics will require that the innermost layer of vertex detectors will be able to sustain fluencies up to 1016 neq/cm2. Moreover, in many experiments there is a demand for the minimization of the material budget of the detectors. Therefore, thin pixel devices fabricated on n-type silicon are a natural choice to fulfill these requirements due to their rad-hard performances and low active volume. We present an R&D activity aimed at developing a new thin hybrid pixel device in the framework of PANDA experiments. The detector of this new device is a p-on-n pixel sensor realized starting from epitaxial silicon wafers and back thinned up to 50-100 μm after process completion. We present the main technological steps and some electrical characterization on the fabricated devices before and after back thinning and after bump bonding to the front-end electronics.

  3. CMOS Active Pixel Sensors as energy-range detectors for proton Computed Tomography

    NASA Astrophysics Data System (ADS)

    Esposito, M.; Anaxagoras, T.; Evans, P. M.; Green, S.; Manolopoulos, S.; Nieto-Camero, J.; Parker, D. J.; Poludniowski, G.; Price, T.; Waltham, C.; Allinson, N. M.

    2015-06-01

    Since the first proof of concept in the early 70s, a number of technologies has been proposed to perform proton CT (pCT), as a means of mapping tissue stopping power for accurate treatment planning in proton therapy. Previous prototypes of energy-range detectors for pCT have been mainly based on the use of scintillator-based calorimeters, to measure proton residual energy after passing through the patient. However, such an approach is limited by the need for only a single proton passing through the energy-range detector in a read-out cycle. A novel approach to this problem could be the use of pixelated detectors, where the independent read-out of each pixel allows to measure simultaneously the residual energy of a number of protons in the same read-out cycle, facilitating a faster and more efficient pCT scan. This paper investigates the suitability of CMOS Active Pixel Sensors (APSs) to track individual protons as they go through a number of CMOS layers, forming an energy-range telescope. Measurements performed at the iThemba Laboratories will be presented and analysed in terms of correlation, to confirm capability of proton tracking for CMOS APSs.

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

    NASA Astrophysics Data System (ADS)

    Watt, J.; Bates, R.; Campbell, M.; Mathieson, K.; Mikulec, B.; O'Shea, V.; Passmore, M.-S.; Schwarz, C.; Smith, K. M.; Whitehill, C.; XIMAGE Project

    2001-03-01

    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 μm thick SI-LEC GaAs detector patterned in a 64×64 array of 170 μm pitch square pixels, bump-bonded to readout electronics operating in single photon counting mode. Intensity peaks in the powder diffraction pattern of KNbO 3 have been resolved and compared with results using the standard scintillator, and a PCD predecessor (the Ω3). 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 Ω3 by using a shutter based acquisition mode. A brief demonstration of the possibilities of the system for dental radiography and image processing are given, showing a marked reduction in patient dose and dead time compared with film.

  5. Investigating the Inverse Square Law with the Timepix Hybrid Silicon Pixel Detector: A CERN [at] School Demonstration Experiment

    ERIC Educational Resources Information Center

    Whyntie, T.; Parker, B.

    2013-01-01

    The Timepix hybrid silicon pixel detector has been used to investigate the inverse square law of radiation from a point source as a demonstration of the CERN [at] school detector kit capabilities. The experiment described uses a Timepix detector to detect the gamma rays emitted by an [superscript 241]Am radioactive source at a number of different…

  6. Application of Pixel-cell Detector Technology for Advanced Neutron Beam Monitors

    SciTech Connect

    Kopp, Daniel M.

    2011-01-11

    Application of Pixel-Cell Detector Technology for Advanced Neutron Beam Monitors Specifications of currently available neutron beam detectors limit their usefulness at intense neutron beams of large-scale national user facilities used for the advanced study of materials. A large number of neutron-scattering experiments require beam monitors to operate in an intense neutron beam flux of >10E+7 neutrons per second per square centimeter. For instance, a 4 cm x 4 cm intense beam flux of 6.25 x 10E+7 n/s/cm2 at the Spallation Neutron Source will put a flux of 1.00 x 10E+9 n/s at the beam monitor. Currently available beam monitors with a typical efficiency of 1 x 10E-4 will need to be replaced in less than two years of operation due to wire and gas degradation issues. There is also a need at some instruments for beam position information that are beyond the capabilities of currently available He-3 and BF3 neutron beam monitors. ORDELA, Inc.’s research under USDOE SBIR Grant (DE-FG02-07ER84844) studied the feasibility of using pixel-cell technology for developing a new generation of stable, long-life neutron beam monitors. The research effort has led to the development and commercialization of advanced neutron beam detectors that will directly benefit the Spallation Neutron Source and other intense neutron sources such as the High Flux Isotope Reactor. A prototypical Pixel-Cell Neutron Beam Monitor was designed and constructed during this research effort. This prototype beam monitor was exposed to an intense neutron beam at the HFIR SNS HB-2 test beam site. Initial measurements on efficiency, uniformity across the detector, and position resolution yielded excellent results. The development and test results have provided the required data to initiate the fabrication and commercialization of this next generation of neutron-detector systems. ORDELA, Inc. has (1) identified low-cost design and fabrication strategies, (2) developed and built pixel-cell detectors and

  7. ATLAS Pixel Detector ROD card from IBL towards Layers 2 and 1

    NASA Astrophysics Data System (ADS)

    Balbi, G.; Falchieri, D.; Gabrielli, A.; Lama, L.; Giangiacomi, N.; Travaglini, R.

    2016-01-01

    The incoming and future upgrades of LHC will require better performance by the data acquisition system, especially in terms of throughput due to the higher luminosity that is expected. For this reason, during the first shutdown of the LHC collider in 2013/14, the ATLAS Pixel Detector has been equipped with a fourth layer— the Insertable B-Layer or IBL—located at a radius smaller than the present three layers. To read out the new layer of pixels, with a smaller pixel size with respect to the other outer layers, a front end ASIC (FE-I4) was designed as well as a new off-detector read-out chain. The latter, accordingly to the structure of the other layers of pixels, is composed mainly of two 9U-VME read-out off-detector cards called the Back-Of-Crate (BOC) and Read-Out Driver (ROD). The ROD is used for data and event formatting and for configuration and control of the overall read-out electronics. After some prototyping samples were completed, a pre-production batch of 5 ROD cards was delivered with the final layout. Another production of 15 ROD cards was done in Fall 2013, and commissioning was completed in 2014. Altogether 14 cards are necessary for the 14 staves of the IBL detector, one additional card is required by the Diamond Beam Monitor (DBM), and additional spare ROD cards were produced for a total initial batch of 20 boards. This paper describes some integration tests that were performed and our plan to install the new DAQ chain for the layer 2, which is the outermost, and layer 1, which is external to the B-layer. This latter is the only layer that will not be upgraded to a higher readout speed. Rather, it will be switched off in the near future as it has too many damaged sensors that were not possible to rework. To do that, slices of the IBL read-out chain have been instrumented, and ROD performance is verified on a test bench mimicking a small-sized final setup. Thus, this contribution reports also how the adoption of the IBL ROD for ATLAS Pixel

  8. Advanced numerical modeling and hybridization techniques for third-generation infrared detector pixel arrays

    NASA Astrophysics Data System (ADS)

    Schuster, Jonathan

    Infrared (IR) detectors are well established as a vital sensor technology for military, defense and commercial applications. Due to the expense and effort required to fabricate pixel arrays, it is imperative to develop numerical simulation models to perform predictive device simulations which assess device characteristics and design considerations. Towards this end, we have developed a robust three-dimensional (3D) numerical simulation model for IR detector pixel arrays. We used the finite-difference time-domain technique to compute the optical characteristics including the reflectance and the carrier generation rate in the device. Subsequently, we employ the finite element method to solve the drift-diffusion equations to compute the electrical characteristics including the I(V) characteristics, quantum efficiency, crosstalk and modulation transfer function. We use our 3D numerical model to study a new class of detector based on the nBn-architecture. This detector is a unipolar unity-gain barrier device consisting of a narrow-gap absorber layer, a wide-gap barrier layer, and a narrow-gap collector layer. We use our model to study the underlying physics of these devices and to explain the anomalously long lateral collection lengths for photocarriers measured experimentally. Next, we investigate the crosstalk in HgCdTe photovoltaic pixel arrays employing a photon-trapping (PT) structure realized with a periodic array of pillars intended to provide broadband operation. The PT region drastically reduces the crosstalk; making the use of the PT structures not only useful to obtain broadband operation, but also desirable for reducing crosstalk, especially in small pitch detector arrays. Then, the power and flexibility of the nBn architecture is coupled with a PT structure to engineer spectrally filtering detectors. Last, we developed a technique to reduce the cost of large-format, high performance HgCdTe detectors by nondestructively screen-testing detector arrays prior

  9. Monte Carlo based performance assessment of different animal PET architectures using pixellated CZT detectors

    NASA Astrophysics Data System (ADS)

    Visvikis, D.; Lefevre, T.; Lamare, F.; Kontaxakis, G.; Santos, A.; Darambara, D.

    2006-12-01

    The majority of present position emission tomography (PET) animal systems are based on the coupling of high-density scintillators and light detectors. A disadvantage of these detector configurations is the compromise between image resolution, sensitivity and energy resolution. In addition, current combined imaging devices are based on simply placing back-to-back and in axial alignment different apparatus without any significant level of software or hardware integration. The use of semiconductor CdZnTe (CZT) detectors is a promising alternative to scintillators for gamma-ray imaging systems. At the same time CZT detectors have the potential properties necessary for the construction of a truly integrated imaging device (PET/SPECT/CT). The aims of this study was to assess the performance of different small animal PET scanner architectures based on CZT pixellated detectors and compare their performance with that of state of the art existing PET animal scanners. Different scanner architectures were modelled using GATE (Geant4 Application for Tomographic Emission). Particular scanner design characteristics included an overall cylindrical scanner format of 8 and 24 cm in axial and transaxial field of view, respectively, and a temporal coincidence window of 8 ns. Different individual detector modules were investigated, considering pixel pitch down to 0.625 mm and detector thickness from 1 to 5 mm. Modified NEMA NU2-2001 protocols were used in order to simulate performance based on mouse, rat and monkey imaging conditions. These protocols allowed us to directly compare the performance of the proposed geometries with the latest generation of current small animal systems. Results attained demonstrate the potential for higher NECR with CZT based scanners in comparison to scintillator based animal systems.

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

    PubMed Central

    Giewekemeyer, Klaus; Philipp, Hugh T.; Wilke, Robin N.; Aquila, Andrew; Osterhoff, Markus; Tate, Mark W.; Shanks, Katherine S.; Zozulya, Alexey V.; Salditt, Tim; Gruner, Sol M.; Mancuso, Adrian P.

    2014-01-01

    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 × 108 8-keV photons pixel−1 s−1, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 1010 photons µm−2 s−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. PMID:25178008

  11. Soft X-Ray Spectrometer Using 100-Pixel STJ Detectors for Synchrotron Radiation

    SciTech Connect

    Shiki, Shigetomo; Zen, Nobuyuki; Ukibe, Masahiro; Ohkubo, Masataka

    2009-12-16

    Fluorescent X-ray absorption fine structure (XAFS) is an important tool for material analysis, especially for the measurement of chemical states or local structures of elements. Semiconductor detectors are usually used for separating the fluorescent of elements in question from background fluorescence. However, the semiconductor detectors cannot always discriminate K-lines of light elements and L-lines of various elements as different X-ray peaks at an energy range below about 3 keV. Superconducting tunnel junction (STJ) detectors are promising device for the soft X-ray at synchrotron radiation beam lines because of excellent energy resolution, high detection efficiency, and high counting rate. We are constructing a fluorescent X-ray spectrometer having 100-pixel array of STJs with 200 {mu}m square. The array detector is mounted on a liquid cryogen-free {sup 3}He cryostat. The sensitive area is the largest among the superconducting X-ray spectrometers operating at synchrotron beam lines. Each pixel is connected to a room temperature readout circuit that consists of a charge sensitive amplifier and a pulse height analyzer. The spectrometer will achieve a total solid angle of {approx}0.01 sr and a maximum counting rate of more than 1 M count per second. The present status of developments of our fluorescent X-ray spectrometer was reported.

  12. Verification of Dosimetry Measurements with Timepix Pixel Detectors for Space Applications

    NASA Technical Reports Server (NTRS)

    Kroupa, M.; Pinsky, L. S.; Idarraga-Munoz, J.; Hoang, S. M.; Semones, E.; Bahadori, A.; Stoffle, N.; Rios, R.; Vykydal, Z.; Jakubek, J.; Pospisil, S.; Turecek, D.; Kitamura, H.

    2014-01-01

    The current capabilities of modern pixel-detector technology has provided the possibility to design a new generation of radiation monitors. Timepix detectors are semiconductor pixel detectors based on a hybrid configuration. As such, the read-out chip can be used with different types and thicknesses of sensors. For space radiation dosimetry applications, Timepix devices with 300 and 500 microns thick silicon sensors have been used by a collaboration between NASA and University of Houston to explore their performance. For that purpose, an extensive evaluation of the response of Timepix for such applications has been performed. Timepix-based devices were tested in many different environments both at ground-based accelerator facilities such as HIMAC (Heavy Ion Medical Accelerator in Chiba, Japan), and at NSRL (NASA Space Radiation Laboratory at Brookhaven National Laboratory in Upton, NY), as well as in space on board of the International Space Station (ISS). These tests have included a wide range of the particle types and energies, from protons through iron nuclei. The results have been compared both with other devices and theoretical values. This effort has demonstrated that Timepix-based detectors are exceptionally capable at providing accurate dosimetry measurements in this application as verified by the confirming correspondence with the other accepted techniques.

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

    PubMed

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

    2012-11-01

    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. PMID:23032372

  14. SMARTPIX, a photon-counting pixel detector for synchrotron applications based on Medipix3RX readout chip and active edge pixel sensors

    NASA Astrophysics Data System (ADS)

    Ponchut, C.; Collet, E.; Hervé, C.; Le Caer, T.; Cerrai, J.; Siron, L.; Dabin, Y.; Ribois, J. F.

    2015-01-01

    Photon-counting pixel detectors are now routinely used on synchrotron beamlines. Many applications benefit from their noiseless mode of operation, single-pixel point spread function and high frame rates. One of their drawbacks is a discontinuous detection area due to the space-consuming wirebonded connections of the readout chips. Moreover, charge sharing limits their efficiency and their energy discrimination capabilities. In order to overcome these issues the ESRF is developing SMARTPIX,a scalable and versatile pixel detector system with minimized dead areas and with energy resolving capabilities based on the MEDIPIX3RX readout chip. SMARTPIX exploits the through-silicon via technology implemented on MEDIPIX3RX, the active edge sensor processing developed in particular at ADVACAM, and the on-chip analog charge summing feature of MEDIPIX3RX. This article reports on system architecture, unit module structure, data acquisition electronics, target characteristics and applications.

  15. Radiation tolerance of the readout chip for the Phase I upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Hoss, J.; Kästli, H.-C.; Meier, B.; Rohe, T.; Starodumov, A.

    2016-01-01

    For the Phase I upgrade of the CMS pixel detector a new digital readout chip (ROC) has been developed. An important part of the design verification are irradiation studies to ensure sufficient radiation tolerance. The paper summarizes results of the irradiation studies on the final ROC design for the detector layers 2 - 4. Samples have been irradiated with 23 MeV protons to accumulate the expected lifetime dose of 0.5 MGy and up to 1.1 MGy to project the performance of the ROC for layer 1 of the detector. It could be shown that the design is sufficiently radiation tolerant and that all performance parameters stay within their specifications. Additionally, very high doses of up to 4.2 MGy have been tested to explore the limits of the current chip design on 250 nm CMOS technology. The study confirmed that samples irradiated up to the highest dose could be successfully operated with test pulses.

  16. Improving detector spatial resolution using pixelated scintillators with a barrier rib structure

    NASA Astrophysics Data System (ADS)

    Liu, Langechuan; Lu, Minghui; Cao, Wanqing; Peng, Luke; Chen, Arthur

    2016-03-01

    Indirect conversion flat panel detectors (FPDs) based on amorphous silicon (a-Si) technology are widely used in digital X-ray imaging. In such FPDs a scintillator layer is used for converting X-rays into visible light photons. However, the lateral spread of these photons inside the scintillator layer reduces spatial resolution of the FPD. In this study, FPDs incorporating pixelated scintillators with a barrier rib structure were developed to limit lateral spread of light photons thereby improving spatial resolution. For the pixelated scintillator, a two-dimensional barrier rib structure was first manufactured on a substrate layer, coated with reflective materials, and filled to the rim with the scintillating material of gadolinium oxysulfide (GOS). Several scintillator samples were fabricated, with pitch size varying from 160 to 280 μm and rib height from 200 to 280 μm. The samples were directly coupled to an a-Si flat panel photodiode array with a pitch of 200 μm to convert optical photons to electronic signals. With the pixelated scintillator, the detector modulation transfer function was shown to improve significantly (by 94% at 2 cycle/mm) compared to a detector using an unstructured GOS layer. However, the prototype does show lower sensitivity due to the decrease in scintillator fill factor. The preliminary results demonstrated the feasibility of using the barrier-rib structure to improve the spatial resolution of FPDs. Such an improvement would greatly benefit nondestructive testing applications where the spatial resolution is the most important parameter. Further investigation will focus on improving the detector sensitivity and exploring its medical applications.

  17. Development of Superconducting-Tunnel-Junction Array Detectors with Three-Dimensional Structure Beyond 1000-Pixels

    NASA Astrophysics Data System (ADS)

    Fujii, Go; Ukibe, Masahiro; Shiki, Shigetomo; Ohkubo, Masataka

    2016-07-01

    Superconducting-tunnel-junction (STJ) array X-ray detectors have exhibited excellent characteristics for fluorescence-yield X-ray absorption fine structure (XAFS) in a soft X-ray range. For high-throughput XAFS analyses, we developed a new close-packed STJ arrangement with a space of 10 \\upmu m (use the correct space) between adjacent STJ pixels by using three-dimensional multilayer structure (3D-STJ) with the wiring layer underneath the STJ pixel layer. In this work, in order to solve a double-peak response originating from absorption events in the top and bottom electrodes, we have fabricated the 3D-STJ with an asymmetric layer structure. Single-peak response for the soft X-rays below 0.7 keV was obtained. The closed-packed 3D-STJ array detector with 100 pixels has an operation yield of 93 % and a mean energy resolution of 12.5 ± 0.7 eV in full-width at half-maximum for the C-Kα X-ray.

  18. Pixelated detectors and improved efficiency for magnetic imaging in STEM differential phase contrast.

    PubMed

    Krajnak, Matus; McGrouther, Damien; Maneuski, Dzmitry; Shea, Val O'; McVitie, Stephen

    2016-06-01

    The application of differential phase contrast imaging to the study of polycrystalline magnetic thin films and nanostructures has been hampered by the strong diffraction contrast resulting from the granular structure of the materials. In this paper we demonstrate how a pixelated detector has been used to detect the bright field disk in aberration corrected scanning transmission electron microscopy (STEM) and subsequent processing of the acquired data allows efficient enhancement of the magnetic contrast in the resulting images. Initial results from a charged coupled device (CCD) camera demonstrate the highly efficient nature of this improvement over previous methods. Further hardware development with the use of a direct radiation detector, the Medipix3, also shows the possibilities where the reduction in collection time is more than an order of magnitude compared to the CCD. We show that this allows subpixel measurement of the beam deflection due to the magnetic induction. While the detection and processing is data intensive we have demonstrated highly efficient DPC imaging whereby pixel by pixel interpretation of the induction variation is realised with great potential for nanomagnetic imaging. PMID:27085170

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

    SciTech Connect

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, E.; Moreno Barbosa, F.

    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.

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

    NASA Astrophysics Data System (ADS)

    Chumacero, E. Miguel; De Celis Alonso, B.; Martínez Hernández, M. I.; Vargas, G.; Moreno Barbosa, F.; Moreno Barbosa, E.

    2014-11-01

    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.

  1. New concept of a submillimetric pixellated Silicon detector for intracerebral application

    NASA Astrophysics Data System (ADS)

    Benoit, M.; Märk, J.; Weiss, P.; Benoit, D.; Clemens, J. C.; Fougeron, D.; Janvier, B.; Jevaud, M.; Karkar, S.; Menouni, M.; Pain, F.; Pinot, L.; Morel, C.; Laniece, P.

    2011-12-01

    A new beta+ radiosensitive microprobe implantable in rodent brain dedicated to in vivo and autonomous measurements of local time activity curves of beta radiotracers in a volume of brain tissue of a few mm3 has been developed recently. This project expands the concept of the previously designed beta microprobe, which has been validated extensively in neurobiological experiments performed on anesthetized animals. Due to its limitations considering recordings on awake and freely moving animals, we have proposed to develop a wireless setup that can be worn by an animal without constraining its movements. To that aim, we have chosen a highly beta sensitive Silicon-based detector to devise a compact pixellated probe. Miniaturized wireless electronics is used to read-out and transfer the measurement data. Initial Monte-Carlo simulations showed that high resistive Silicon pixels are appropriate for this purpose, with their dimensions to be adapted to our specific signals. More precisely, we demonstrated that 200 μm thick pixels with an area of 200 μm×500 μm are optimized in terms of beta+sensitivity versus relative transparency to the gamma background. Based on this theoretical study, we now present the development of the novel sensor, including the system simulations with technology computer-assisted design (TCAD) to investigate specific configurations of guard rings and their potential to increase the electrical isolation and stabilization of the pixel, as well as the corresponding physical tests to validate the particular geometries of this new sensor.

  2. Evaluation of Compton gamma camera prototype based on pixelated CdTe detectors.

    PubMed

    Calderón, Y; Chmeissani, M; Kolstein, M; De Lorenzo, G

    2014-06-01

    A proposed Compton camera prototype based on pixelated CdTe is simulated and evaluated in order to establish its feasibility and expected performance in real laboratory tests. The system is based on module units containing a 2×4 array of square CdTe detectors of 10×10 mm(2) area and 2 mm thickness. The detectors are pixelated and stacked forming a 3D detector with voxel sizes of 2 × 1 × 2 mm(3). The camera performance is simulated with Geant4-based Architecture for Medicine-Oriented Simulations(GAMOS) and the Origin Ensemble(OE) algorithm is used for the image reconstruction. The simulation shows that the camera can operate with up to 10(4) Bq source activities with equal efficiency and is completely saturated at 10(9) Bq. The efficiency of the system is evaluated using a simulated (18) F point source phantom in the center of the Field-of-View (FOV) achieving an intrinsic efficiency of 0.4 counts per second per kilobecquerel. The spatial resolution measured from the point spread function (PSF) shows a FWHM of 1.5 mm along the direction perpendicular to the scatterer, making it possible to distinguish two points at 3 mm separation with a peak-to-valley ratio of 8. PMID:24932209

  3. Studies of the possibility to use Gas Pixel Detector as a fast trigger tracking device

    NASA Astrophysics Data System (ADS)

    Sinev, N.; Bashindzhagyan, G.; Korotkova, N.; Romaniouk, A.; Tikhomirov, V.

    2016-02-01

    Gas Pixel Detector (GPD) technology offers new possibilities, which make them very attractive for application in existing and future accelerator experiments and beyond. GPDs combine advantages of silicon and gaseous detectors. They can be produced radiation hard and with low power consumption using relatively cheap technology. Low capacitance of the individual pixel channel allows us to obtain a large signal to noise ratio. Using a time projection method for GPD readout one obtains 3D track image with precise coordinate (31 µm) and angular information (0.40°). This feature would allow us to achieve performance of one GPD layer equal to a few layers of silicon detectors. Implementation of a fast readout and data processing at the front-end level allows one to reconstruct a track segment in less than 1 μs, and to use this information for the first level trigger generation. The relevant algorithms of data acquisition and analysis are described and the results of simulations are presented in this paper.

  4. Optimizing Pinhole and Parallel Hole Collimation for Scintimammography With Compact Pixellated Detectors

    SciTech Connect

    Mark F. Smith; Stan Majewski; Andrew G. Weisenberger

    2002-11-01

    The relative resolution and sensitivity advantages of pinhole and parallel hole collimators for planar scintimammography with compact, pixellated gamma detectors were investigated using analytic models. Collimator design was studied as follows. A desired object resolution was specified for a pixellated detector with a given crystal size and intrinsic spatial resolution and for a given object-to- collimator distance. Using analytic formulas, pinhole and parallel hole collimator parameters were calculated that satisfy this object resolution with optimal geometric sensitivity. Analyses were performed for 15 cm x 20 cm field of view detectors with crystal elements 1.0, 2.0 and 3.0 mm on a side and 140 keV incident photons. The sensitivity for a given object resolution was greater for pinhole collimation at smaller distances, as expected. The object distance at which the pinhole and parallel hole sensitivity curves cross each other is important. The crossover distances increased with larger crystal size for a constant object resolution and increased as the desired object resolution decreases for a constant crystal size. For example, for 4 mm object resolution and a pinhole collimator with focal length 13 cm, these distances were 5.5 cm, 6.5 cm and 8 cm for the 1 mm, 2 mm and 3 mm crystal detectors, respectively. The results suggest a strategy of parallel hole collimation for whole breast imaging and pinhole collimation for imaging focal uptake. This could be accomplished with a dual detector system with a different collimator type on each head or a single head system equipped with two collimators and a rapid switching mechanism.

  5. Development of an Indium bump bond process for silicon pixel detectors at PSI

    NASA Astrophysics Data System (ADS)

    Broennimann, Ch.; Glaus, F.; Gobrecht, J.; Heising, S.; Horisberger, M.; Horisberger, R.; Kästli, H. C.; Lehmann, J.; Rohe, T.; Streuli, S.

    2006-09-01

    The hybrid pixel detectors used in the high-energy physics experiments currently under construction use a vertical connection technique, the so-called bump bonding. As the pitch below 100 μm, required in these applications, cannot be fulfilled with standard industrial processes (e.g. the IBM C4 process), an in-house bump bond process using reflowed indium bumps was developed at PSI as part of the R&D for the CMS-pixel detector. The bump deposition on the sensor is performed in two subsequent lift-off steps. As the first photolithographic step a thin under bump metalization (UBM) is sputtered onto bump pads. It is wettable by indium and defines the diameter of the bump. The indium is evaporated via a second photolithographic step with larger openings and is reflowed afterwards. The height of the balls is defined by the volume of the indium. On the readout chip only one photolithographic step is carried out to deposit the UBM and a thin indium layer for better adhesion. After mating both parts a second reflow is performed for self-alignment and obtaining high mechanical strength. For the placement of the chips a manual and an automatic machine were constructed. The former is very flexible in handling different chip and module geometries but has a limited throughput while the latter features a much higher grade of automatization and is therefore much more suited for producing hundreds of modules with a well-defined geometry. The reliability of this process was proven by the successful construction of the PILATUS detector. The construction of PILATUS 6M (60 modules) and the CMS pixel barrel (roughly 800 modules) has started in early 2006.

  6. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    PubMed Central

    Cai, Liang; Meng, Ling-Jian

    2013-01-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X–Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2–5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper. PMID:24371365

  7. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system.

    PubMed

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper. PMID:24371365

  8. Hybrid pixel-waveform CdTe/CZT detector for use in an ultrahigh resolution MRI compatible SPECT system

    NASA Astrophysics Data System (ADS)

    Cai, Liang; Meng, Ling-Jian

    2013-02-01

    In this paper, we will present a new small pixel CdTe/CZT detector for sub-500 μm resolution SPECT imaging application inside MR scanner based on a recently developed hybrid pixel-waveform (HPWF) readout circuitry. The HPWF readout system consists of a 2-D multi-pixel circuitry attached to the anode pixels to provide the X-Y positions of interactions, and a high-speed digitizer to read out the pulse-waveform induced on the cathode. The digitized cathode waveform could provide energy deposition information, precise timing and depth-of-interaction information for gamma ray interactions. Several attractive features with this HPWF detector system will be discussed in this paper. To demonstrate the performance, we constructed several prototype HPWF detectors with pixelated CZT and CdTe detectors of 2-5 mm thicknesses, connected to a prototype readout system consisting of energy-resolved photon-counting ASIC for readout anode pixels and an Agilent high-speed digitizer for digitizing the cathode signals. The performances of these detectors based on HPWF are discussed in this paper.

  9. Nanopillar optical antenna nBn detectors for subwavelength infrared pixels

    NASA Astrophysics Data System (ADS)

    Hung, Chung Hong; Senanayake, Pradeep; Lee, Wook-Jae; Farrell, Alan; Hsieh, Nick; Huffaker, Diana L.

    2015-06-01

    The size, weight and power (SWaP) of state of the art infrared focal plane arrays are limited by the pixel size approaching the diffraction limit. We investigate a novel detector architecture which allows improvements in detectivity by shrinking the absorber volume while maintaining high quantum efficiency and wide field of view (FOV). It has been previously shown that the Nanopillar Optical Antenna (NOA) utilizes 3D plasmonic modes to funnel light into a subwavelength nanopillar absorber. We show detailed electro-optical simulations for the NOA-nBn architecture for overcoming generation recombination current with suitable surface passivation to achieve background limited infrared performance.

  10. Assembly and test of the gas pixel detector for X-ray polarimetry

    NASA Astrophysics Data System (ADS)

    Li, H.; Feng, H.; Muleri, F.; Bellazzini, R.; Minuti, M.; Soffitta, P.; Brez, A.; Spandre, G.; Pinchera, M.; Sgró, C.; Baldini, L.; She, R.; Costa, E.

    2015-12-01

    The gas pixel detector (GPD) dedicated for photoelectric X-ray polarimetry is selected as the focal plane detector for the ESA medium-class mission concept X-ray Imaging and Polarimetry Explorer (XIPE). Here we show the design, assembly, and preliminary test results of a small GPD for the purpose of gas mixture optimization needed for the phase A study of XIPE. The detector is assembled in house at Tsinghua University following a design by the INFN-Pisa group. The improved detector design results in a good uniformity for the electric field. Filled with pure dimethyl ether (DME) at 0.8 atm, the measured energy resolution is 18% at 6 keV and inversely scales with the square root of the X-ray energy. The measured modulation factor is well consistent with that from simulation, up to ~0.6 above 6 keV. The residual modulation is found to be 0.30 ± 0.15 % at 6 keV for the whole sensitive area, which can be translated into a systematic error of less than 1% for polarization measurement at a confidence level of 99%. The position resolution of the detector is about 80 μm in FWHM, consistent with previous studies and sufficient for XIPE requirements.

  11. Development of a Cost-Effective Modular Pixelated NaI(Tl) Detector for Clinical SPECT Applications

    PubMed Central

    Rozler, Mike; Liang, Haoning; Chang, Wei

    2013-01-01

    A new pixelated detector for high-resolution clinical SPECT applications was designed and tested. The modular detector is based on a scintillator block comprised of 2.75×2.75×10 mm3 NaI(Tl) pixels and decoded by an array of 51 mm diameter single-anode PMTs. Several configurations, utilizing two types of PMTs, were evaluated using a collimated beam source to measure positioning accuracy directly. Good pixel separation was observed, with correct pixel identification ranging from 60 to 72% averaged over the entire area of the modules, depending on the PMT type and configuration. This translates to a significant improvement in positioning accuracy compared to continuous slab detectors of the same thickness, along with effective reduction of “dead” space at the edges. The observed 10% average energy resolution compares well to continuous slab detectors. The combined performance demonstrates the suitability of pixelated detectors decoded with a relatively small number of medium-sized PMTs as a cost-effective approach for high resolution clinical SPECT applications, in particular those involving curved detector geometries. PMID:24146436

  12. Deployment of the CMS Tracker AMC as backend for the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Auzinger, G.

    2016-01-01

    The silicon pixel detector of the CMS experiment at CERN will be replaced with an upgraded version at the beginning of 2017 with the new detector featuring an additional barrel- and end-cap layer resulting in an increased number of fully digital read-out links running at 400 Mbps. New versions of the PSI46 Read-Out Chip and Token Bit Manager have been developed to operate at higher rates and reduce data loss. Front-End Controller and Front-End Driver boards, based on the μTCA compatible CMS Tracker AMC, a variant of the FC7 card, are being developed using different mezzanines to host the optical links for the digital read-out and control system. An overview of the system architecture is presented, with details on the implementation, and first results obtained from test systems.

  13. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    DOE PAGESBeta

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-05-07

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. As a result, a method for measuring themore » arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.« less

  14. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    NASA Astrophysics Data System (ADS)

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-08-01

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. A method for measuring the arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.

  15. Characterization of Depleted Monolithic Active Pixel detectors implemented with a high-resistive CMOS technology

    NASA Astrophysics Data System (ADS)

    Kishishita, T.; Hemperek, T.; Rymaszewski, P.; Hirono, T.; Krüger, H.; Wermes, N.

    2016-07-01

    We present the recent development of DMAPS (Depleted Monolithic Active Pixel Sensor), implemented with a Toshiba 130 nm CMOS process. Unlike in the case of standard MAPS technologies which are based on an epi-layer, this process provides a high-resistive substrate that enables larger signal and faster charge collection by drift in a 50 - 300 μm thick depleted layer. Since this process also enables the use of deep n-wells to isolate the collection electrodes from the thin active device layer, NMOS and PMOS transistors are available for the readout electronics in each pixel cell. In order to characterize the technology, we implemented a simple three transistor readout with a variety of pixel pitches and input FET sizes. This layout variety gives us a clue on sensor characteristics for future optimization, such as the input detector capacitance or leakage current. In the initial measurement, the radiation spectra were obtained from 55Fe with an energy resolution of 770 eV (FWHM) and 90Sr with the MVP of 4165 e-.

  16. Radiation tolerance of prototype BTeV pixel detector readout chips

    SciTech Connect

    Gabriele Chiodini et al.

    2002-07-12

    High energy and nuclear physics experiments need tracking devices with increasing spatial precision and readout speed in the face of ever-higher track densities and increased radiation environments. The new generation of hybrid pixel detectors (arrays of silicon diodes bump bonded to arrays of front-end electronic cells) is the state of the art technology able to meet these challenges. We report on irradiation studies performed on BTeV pixel readout chip prototypes exposed to a 200 MeV proton beam at Indiana University Cyclotron Facility. Prototype pixel readout chip preFPIX2 has been developed at Fermilab for collider experiments and implemented in standard 0.25 micron CMOS technology following radiation tolerant design rules. The tests confirmed the radiation tolerance of the chip design to proton total dose up to 87 MRad. In addition, non destructive radiation-induced single event upsets have been observed in on-chip static registers and the single bit upset cross section has been extensively measured.

  17. Coded aperture imaging with a HURA coded aperture and a discrete pixel detector

    NASA Astrophysics Data System (ADS)

    Byard, Kevin

    An investigation into the gamma ray imaging properties of a hexagonal uniformly redundant array (HURA) coded aperture and a detector consisting of discrete pixels constituted the major research effort. Such a system offers distinct advantages for the development of advanced gamma ray astronomical telescopes in terms of the provision of high quality sky images in conjunction with an imager plane which has the capacity to reject background noise efficiently. Much of the research was performed as part of the European Space Agency (ESA) sponsored study into a prospective space astronomy mission, GRASP. The effort involved both computer simulations and a series of laboratory test images. A detailed analysis of the system point spread function (SPSF) of imaging planes which incorporate discrete pixel arrays is presented and the imaging quality quantified in terms of the signal to noise ratio (SNR). Computer simulations of weak point sources in the presence of detector background noise were also investigated. Theories developed during the study were evaluated by a series of experimental measurements with a Co-57 gamma ray point source, an Anger camera detector, and a rotating HURA mask. These tests were complemented by computer simulations designed to reproduce, as close as possible, the experimental conditions. The 60 degree antisymmetry property of HURA's was also employed to remove noise due to detector systematic effects present in the experimental images, and rendered a more realistic comparison of the laboratory tests with the computer simulations. Plateau removal and weighted deconvolution techniques were also investigated as methods for the reduction of the coding error noise associated with the gamma ray images.

  18. SemiSPECT: A Small-animal Imaging System Based on Eight CdZnTe Pixel Detectors

    PubMed Central

    Peterson, Todd E.; Kim, Hyunki; Crawford, Michael J.; Gershman, Benjamin M.; Hunter, William C.J.; Barber, H. Bradford; Furenlid, Lars R.; Wilson, Donald W.; Woolfenden, James M.; Barrett, Harrison H.

    2015-01-01

    We have constructed a SPECT system for small animals that utilizes eight CdZnTe pixel detectors. The eight detectors are arranged in a single octagonal ring, where each views the object to be imaged through a single pinhole. Additional projections are obtained via rotation of the animal. Each CdZnTe detector is approximately 2 mm in thickness and is patterned on one surface into a 64×64 array of pixels with 380 micron pitch. We have designed an electronic readout system capable of collecting data from the eight detectors in listmode. In this scheme each event entry for a gamma-ray hit includes the pulse height of the pixel with the largest signal and the pulse height for each of its eight nearest neighbors. We present details of the overall design, the electronics, and system performance. PMID:26568674

  19. Pixelated CdTe detectors to overcome intrinsic limitations of crystal based positron emission mammographs

    NASA Astrophysics Data System (ADS)

    De Lorenzo, G.; Chmeissani, M.; Uzun, D.; Kolstein, M.; Ozsahin, I.; Mikhaylova, E.; Arce, P.; Cañadas, M.; Ariño, G.; Calderón, Y.

    2013-01-01

    A positron emission mammograph (PEM) is an organ dedicated positron emission tomography (PET) scanner for breast cancer detection. State-of-the-art PEMs employing scintillating crystals as detection medium can provide metabolic images of the breast with significantly higher sensitivity and specificity with respect to standard whole body PET scanners. Over the past few years, crystal PEMs have dramatically increased their importance in the diagnosis and treatment of early stage breast cancer. Nevertheless, designs based on scintillators are characterized by an intrinsic deficiency of the depth of interaction (DOI) information from relatively thick crystals constraining the size of the smallest detectable tumor. This work shows how to overcome such intrinsic limitation by substituting scintillating crystals with pixelated CdTe detectors. The proposed novel design is developed within the Voxel Imaging PET (VIP) Pathfinder project and evaluated via Monte Carlo simulation. The volumetric spatial resolution of the VIP-PEM is expected to be up to 6 times better than standard commercial devices with a point spread function of 1 mm full width at half maximum (FWHM) in all directions. Pixelated CdTe detectors can also provide an energy resolution as low as 1.5% FWHM at 511 keV for a virtually pure signal with negligible contribution from scattered events.

  20. Characterisation of edgeless technologies for pixellated and strip silicon detectors with a micro-focused X-ray beam

    NASA Astrophysics Data System (ADS)

    Bates, R.; Blue, A.; Christophersen, M.; Eklund, L.; Ely, S.; Fadeyev, V.; Gimenez, E.; Kachkanov, V.; Kalliopuska, J.; Macchiolo, A.; Maneuski, D.; Phlips, B. F.; Sadrozinski, H. F.-W.; Stewart, G.; Tartoni, N.; Zain, R. M.

    2013-01-01

    Reduced edge or ``edgeless'' detector design offers seamless tileability of sensors for a wide range of applications from particle physics to synchrotron and free election laser (FEL) facilities and medical imaging. Combined with through-silicon-via (TSV) technology, this would allow reduced material trackers for particle physics and an increase in the active area for synchrotron and FEL pixel detector systems. In order to quantify the performance of different edgeless fabrication methods, 2 edgeless detectors were characterized at the Diamond Light Source using an 11 μm FWHM 15 keV micro-focused X-ray beam. The devices under test were: a 150 μm thick silicon active edge pixel sensor fabricated at VTT and bump-bonded to a Medipix2 ROIC; and a 300 μm thick silicon strip sensor fabricated at CIS with edge reduction performed by SCIPP and the NRL and wire bonded to an ALiBaVa readout system. Sub-pixel resolution of the 55 μm active edge pixels was achieved. Further scans showed no drop in charge collection recorded between the centre and edge pixels, with a maximum deviation of 5% in charge collection between scanned edge pixels. Scans across the cleaved and standard guard ring edges of the strip detector also show no reduction in charge collection. These results indicate techniques such as the scribe, cleave and passivate (SCP) and active edge processes offer real potential for reduced edge, tiled sensors for imaging detection applications.

  1. Design Studies of a CZT-based Detector Combined with a Pixel-Geometry-Matching Collimator for SPECT Imaging.

    PubMed

    Weng, Fenghua; Bagchi, Srijeeta; Huang, Qiu; Seo, Youngho

    2013-10-01

    Single Photon Emission Computed Tomography (SPECT) suffers limited efficiency due to the need for collimators. Collimator properties largely decide the data statistics and image quality. Various materials and configurations of collimators have been investigated in many years. The main thrust of our study is to evaluate the design of pixel-geometry-matching collimators to investigate their potential performances using Geant4 Monte Carlo simulations. Here, a pixel-geometry-matching collimator is defined as a collimator which is divided into the same number of pixels as the detector's and the center of each pixel in the collimator is a one-to-one correspondence to that in the detector. The detector is made of Cadmium Zinc Telluride (CZT), which is one of the most promising materials for applications to detect hard X-rays and γ-rays due to its ability to obtain good energy resolution and high light output at room temperature. For our current project, we have designed a large-area, CZT-based gamma camera (20.192 cm×20.192 cm) with a small pixel pitch (1.60 mm). The detector is pixelated and hence the intrinsic resolution can be as small as the size of the pixel. Materials of collimator, collimator hole geometry, detection efficiency, and spatial resolution of the CZT detector combined with the pixel-matching collimator were calculated and analyzed under different conditions. From the simulation studies, we found that such a camera using rectangular holes has promising imaging characteristics in terms of spatial resolution, detection efficiency, and energy resolution. PMID:25378898

  2. 3D silicon pixel detectors for the ATLAS Forward Physics experiment

    NASA Astrophysics Data System (ADS)

    Lange, J.; Cavallaro, E.; Grinstein, S.; López Paz, I.

    2015-03-01

    The ATLAS Forward Physics (AFP) project plans to install 3D silicon pixel detectors about 210 m away from the interaction point and very close to the beamline (2-3 mm). This implies the need of slim edges of about 100-200 μm width for the sensor side facing the beam to minimise the dead area. Another challenge is an expected non-uniform irradiation of the pixel sensors. It is studied if these requirements can be met using slightly-modified FE-I4 3D pixel sensors from the ATLAS Insertable B-Layer production. AFP-compatible slim edges are obtained with a simple diamond-saw cut. Electrical characterisations and beam tests are carried out and no detrimental impact on the leakage current and hit efficiency is observed. For devices without a 3D guard ring a remaining insensitive edge of less than 15 μm width is found. Moreover, 3D detectors are non-uniformly irradiated up to fluences of several 1015 neq/cm2 with either a focussed 23 GeV proton beam or a 23 MeV proton beam through holes in Al masks. The efficiency in the irradiated region is found to be similar to the one in the non-irradiated region and exceeds 97% in case of favourable chip-parameter settings. Only in a narrow transition area at the edge of the hole in the Al mask, a significantly lower efficiency is seen. A follow-up study of this effect using arrays of small pad diodes for position-resolved dosimetry via the leakage current is carried out.

  3. Front-end intelligence for triggering and local track measurement in gaseous pixel detectors

    NASA Astrophysics Data System (ADS)

    Gromov, V.; Hessey, N.; Vermeulen, J.

    2012-11-01

    A number of applications in high-energy physics and medicine requires three-dimensional reconstruction of the particle trajectories: for example, high momentum particles in accelerator-based experiments can be identified on the basis of the properties of their tracks, while in proton computed tomography accurate knowledge of the incoming and outgoing beam trajectory is crucial in reconstructing the most probable path of the proton traversing the patient. In this work we investigate the potential of Gaseous Pixel (GridPix) detectors for fast and efficient recognition of tracks and determination of their properties. This includes selection, without external trigger, of tracks with desired angles, for example tracks with small tilt angles corresponding to high momentum particles in a magnetic field. Being able to select these fast and without external input is of interest for the future upgrades of the LHC detectors. In this paper we present a track selection algorithm, and its physical implementation in 130 nm CMOS technology with estimates of power consumption, data rates, latency, and chip area. The Timepix3 chip, currently being designed for a wide range of applications, will also be suitable for readout of GridPix detectors. Both arrival time information (accuracy 1.6 ns) and charge deposit information will be delivered for each hit together with the coordinates of the active pixel. A short overview is presented of its architecture, which allows continuous self-triggered readout of sparsely distributed data with a rate up to 20 × 106 hits cm-2sec-1. The addition of fast track pattern recognition logic to TimePix3 in a successor chip is currently being investigated.

  4. Design Studies of a CZT-based Detector Combined with a Pixel-Geometry-Matching Collimator for SPECT Imaging

    PubMed Central

    Weng, Fenghua; Bagchi, Srijeeta; Huang, Qiu; Seo, Youngho

    2014-01-01

    Single Photon Emission Computed Tomography (SPECT) suffers limited efficiency due to the need for collimators. Collimator properties largely decide the data statistics and image quality. Various materials and configurations of collimators have been investigated in many years. The main thrust of our study is to evaluate the design of pixel-geometry-matching collimators to investigate their potential performances using Geant4 Monte Carlo simulations. Here, a pixel-geometry-matching collimator is defined as a collimator which is divided into the same number of pixels as the detector’s and the center of each pixel in the collimator is a one-to-one correspondence to that in the detector. The detector is made of Cadmium Zinc Telluride (CZT), which is one of the most promising materials for applications to detect hard X-rays and γ-rays due to its ability to obtain good energy resolution and high light output at room temperature. For our current project, we have designed a large-area, CZT-based gamma camera (20.192 cm×20.192 cm) with a small pixel pitch (1.60 mm). The detector is pixelated and hence the intrinsic resolution can be as small as the size of the pixel. Materials of collimator, collimator hole geometry, detection efficiency, and spatial resolution of the CZT detector combined with the pixel-matching collimator were calculated and analyzed under different conditions. From the simulation studies, we found that such a camera using rectangular holes has promising imaging characteristics in terms of spatial resolution, detection efficiency, and energy resolution. PMID:25378898

  5. Ongoing studies for the control system of a serially powered ATLAS pixel detector at the HL-LHC

    NASA Astrophysics Data System (ADS)

    Kersten, S.; Püllen, L.; Zeitnitz, C.

    2016-02-01

    In terms of the phase-2 upgrade of the ATLAS detector, the entire inner tracker (ITk) of ATLAS will be replaced. This includes the pixel detector and the corresponding detector control system (DCS). The current baseline is a serial powering scheme of the detector modules. Therefore a new detector control system is being developed with emphasis on the supervision of serially powered modules. Previous chips had been designed to test the radiation hardness of the technology and the implementation of the modified I2C as well as the implementation of the logic of the CAN protocol. This included tests with triple redundant registers. The described chip is focusing on the implementation in a serial powering scheme. It was designed for laboratory tests, aiming for the proof of principle. The concept of the DCS for ATLAS pixel after the phase-2 upgrade is presented as well as the status of development including tests with the prototype ASIC.

  6. CZT pixel detectors equipped with effective Ohmic contacts; their spectroscopic performance and the enigma of why they thus behave

    NASA Astrophysics Data System (ADS)

    El-Hanany, Uri; Shahar, Allon; Tsigelman, A.

    1999-10-01

    The performance of CZT pixel detectors, with dedicated ICs and electronic processors, have been demonstrated. These nuclear imaging modules, developed primarily for the medical market, may be utilized for other applications, such as large area nuclear spectrometers. An improved crystal growth technique ensures a practical supply of wafers of which high performance detectors are fabricated. We believe that the high spectroscopic quality of these detectors stems from their effective Ohmic behavior, coupled with the geometrical, 'small pixel' effect. The Ohmic operation of these detectors has been described in a schematic way only, where the detailed non-equilibrium mechanism, responsible for it, still remains to be explained in detail. The IMARAD detector type 2, with contacts which strongly limit the dark current, exhibit even improved spectroscopic behavior, due to a dynamic Ohmic behavior of these contacts.

  7. Detailed Studies of Pixelated CZT Detectors Grown with the Modified Horizontal Bridgman Method

    NASA Technical Reports Server (NTRS)

    Jung, I.; Krawczynski, H.; Burger, A.; Guo, M.; Groza, M.

    2007-01-01

    The detector material Cadmium Zinc Telluride (CZT) achieves excellent spatial resolution and good energy resolution over a broad energy range, several keV up to some MeV. Presently, there are two main methods to grow CZT crystals, the Modified High-Pressure Bridgman (MHB) and the High-Pressure Bridgman (HPB) process. The study presented in this paper is based on MHB CZT substrates from the company Orbotech Medical Solutions Ltd. [Orbotech Medical Solutions Ltd., 10 Plaut St., Park Rabin, P.O. Box 2489, Rehovot, Israel, 76124]. Former studies have shown that high-work-function materials on the cathode side reduce the leakage current and, therefore, improve the energy resolution at lower energies. None of the studies have emphasized on the anode contact material. Therefore, we present in this paper the result of a detailed study in which for the first time the cathode material was kept constant and the anode material was varied. We used four different anode materials: Indium, Titanium, Chromium and Gold, metals with work-functions between 4.1 eV and 5.1 eV. The detector size was 2.0 x 2.0 x 0.5 cu cm with 8 x 8 pixels and a pitch of 2.46 mm. The best performance was achieved with the low-work-function materials Indium and Titanium with energy resolutions of 2.0 keV (at 59 keV) and 1.9 keV (at 122 keV) for Titanium and 2.1 keV (at 59 keV) and 2.9 keV (at 122 keV) for Indium. Taking into account the large pixel pitch of 2.46 mm, these resolutions are very competitive in comparison to those achieved with detectors made of material produced with the more expensive conventional HPB method. We present a detailed comparison of our detector response with 3D simulations. The latter comparisons allow us to determine the mobility-lifetime-products (mu tau-products) for electrons and holes. Finally, we evaluated the temperature dependency of the detector performance and ls-products. For many applications temperature dependence is important, therefore, we extended the scope of

  8. Beam test studies of 3D pixel sensors irradiated non-uniformly for the ATLAS forward physics detector

    NASA Astrophysics Data System (ADS)

    Grinstein, S.; Baselga, M.; Boscardin, M.; Christophersen, M.; Da Via, C.; Dalla Betta, G.-F.; Darbo, G.; Fadeyev, V.; Fleta, C.; Gemme, C.; Grenier, P.; Jimenez, A.; Lopez, I.; Micelli, A.; Nelist, C.; Parker, S.; Pellegrini, G.; Phlips, B.; Pohl, D.-L.; Sadrozinski, H. F.-W.; Sicho, P.; Tsiskaridze, S.

    2013-12-01

    Pixel detectors with cylindrical electrodes that penetrate the silicon substrate (so called 3D detectors) offer advantages over standard planar sensors in terms of radiation hardness, since the electrode distance is decoupled from the bulk thickness. In recent years significant progress has been made in the development of 3D sensors, which culminated in the sensor production for the ATLAS Insertable B-Layer (IBL) upgrade carried out at CNM (Barcelona, Spain) and FBK (Trento, Italy). Based on this success, the ATLAS Forward Physics (AFP) experiment has selected the 3D pixel sensor technology for the tracking detector. The AFP project presents a new challenge due to the need for a reduced dead area with respect to IBL, and the in-homogeneous nature of the radiation dose distribution in the sensor. Electrical characterization of the first AFP prototypes and beam test studies of 3D pixel devices irradiated non-uniformly are presented in this paper.

  9. A 2D 4×4 Channel Readout ASIC for Pixelated CdTe Detectors for Medical Imaging Applications

    PubMed Central

    Macias-Montero, Jose-Gabriel; Sarraj, Maher; Chmeissani, Mokhtar; Martínez, Ricardo; Puigdengoles, Carles

    2015-01-01

    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 μm 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 μW. In acquisition mode, the total power consumption of every pixel is 200 μW. An equivalent noise charge (ENC) of 160 e−RMS at maximum gain and negative polarity conditions has been measured at room temperature. PMID:26744545

  10. Imaging of Ra-223 with a small-pixel CdTe detector

    NASA Astrophysics Data System (ADS)

    Scuffham, J. W.; Pani, S.; Seller, P.; Sellin, P. J.; Veale, M. C.; Wilson, M. D.; Cernik, R. J.

    2015-01-01

    Ra-223 Dichloride (Xofigo™) is a promising new radiopharmaceutical offering survival benefit and palliation of painful bone metastases in patients with hormone-refractory prostate cancer [1]. The response to radionuclide therapy and toxicity are directly linked to the absorbed radiation doses to the tumour and organs at risk respectively. Accurate dosimetry necessitates quantitative imaging of the biodistribution and kinetics of the radiopharmaceutical. Although primarily an alpha-emitter, Ra-223 also has some low-abundance X-ray and gamma emissions, which enable imaging of the biodistribution in the patient. However, the low spectral resolution of conventional gamma camera detectors makes in-vivo imaging of Ra-223 challenging. In this work, we present spectra and image data of anthropomorphic phantoms containing Ra-223 acquired with a small-pixel CdTe detector (HEXITEC) [2] with a pinhole collimator. Comparison is made with similar data acquired using a clinical gamma camera. The results demonstrate the advantages of the solid state detector in terms of scatter rejection and quantitative accuracy of the images. However, optimised collimation is needed in order for the sensitivity to rival current clinical systems. As different dosage levels and administration regimens for this drug are explored in current clinical trials, there is a clear need to develop improved imaging technologies that will enable personalised treatments to be designed for patients.

  11. Perspectives of the Pixel Detector Timepix for Needs of Ion Beam Therapy

    NASA Astrophysics Data System (ADS)

    Martišíková, M.; Hartmann, B.; Jäkel, O.; Granja, C.; Jakubek, J.

    2012-08-01

    Radiation therapy with ion beams is a highly precise kind of cancer treatment. In ion beam therapy the finite range of the ion beams in tissue and the increase of ionization density at the end of their path, the Bragg-peak, are exploited. Ions heavier than protons offer in addition increased biological effectiveness and decreased scattering. In this contribution we discuss the potential of a quantum counting and position sensitive semiconductor detector Timepix for its applications in ion beam therapy measurements. It provides high sensitivity and high spatial resolution (pixel pitch 55 μm). The detector, developed by the Medipix Collaboration, consists of a silicon sensor bump bonded to a pixelated readout chip (256 × 256 pixels with 55 μm pitch). An integrated USB-based readout interface together with the Pixelman software enable registering single particles online with 2D-track visualization. The experiments were performed at the Heidelberg Ion Beam Therapy Center (HIT), which is a modern ion beam therapy facility. Patient treatments are performed with proton and carbon ions, which are accelerated by a synchrotron. For dose delivery to the patient an active technique is used: narrow pencil-like beams are scanned over the target volume. The possibility to use the detector for two different applications was investigated: ion spectroscopy and beam delivery monitoring by measurement of secondary charged particles around the patient. During carbon ion therapy, a variety of ion species is created by nuclear fragmentation processes of the primary beam. Since they differ in their biological effectiveness, it is of large interest to measure the ion spectra created under different conditions and to visualize their spatial distribution. The possibility of measurements of ion energy loss in silicon makes Timepix a promising detector for ion-spectroscopic studies in patient-like phantoms. Unpredictable changes in the patient can alter the range of the ion beam in the body

  12. Improvement of the energy resolution of pixelated CdTe detectors for applications in 0νββ searches

    NASA Astrophysics Data System (ADS)

    Gleixner, T.; Anton, G.; Filipenko, M.; Seller, P.; Veale, M. C.; Wilson, M. D.; Zang, A.; Michel, T.

    2015-07-01

    Experiments trying to detect 0νββ are very challenging. Their requirements include a good energy resolution and a good detection efficiency. With current fine pixelated CdTe detectors there is a trade off between the energy resolution and the detection efficiency, which limits their performance. It will be shown with simulations that this problem can be mostly negated by analysing the cathode signal which increases the optimal sensor thickness. We will compare different types of fine pixelated CdTe detectors (Timepix, Dosepix, HEXITEC) from this point of view.

  13. Use of silicon and GaAs pixel detectors for digital autoradiography

    SciTech Connect

    Bertolucci, E.; Conti, M.; Grossi, G.

    1996-12-31

    Solid state detectors made of Si (4.8x8 mm{sup 2}) and GaAs (6.4x8 mm{sup 2}) pixel matrices bump-bonded to the Omega2 and Omega3 electronic read-out systems, developed at CERN for H.E.P. experiments, have been used to obtain autoradiographic images of clusters of human epithelial cells and DNA fragments separated via electrophoresis, both labeled with {sup 32}P. The system has shown a good minimum detectable activity per unit area of 2. 10{sup -4} cps mm{sup -2}, and has proved linear for count rate in the range 0.2-20 cps, typical of autoradiography. The pixel dimensions are 75x500 {mu}m{sup 2} (Si-Omega2) and 50x500 {mu}m{sup 2} (GaAs-Omega3), respectively. We are able to clearly localize clusters of cells which have incorporated the radioactive tracer and DNA fragments on an electrophoretic gel on paper (blots).

  14. Coherent, focus-corrected imaging of optical fiber facets using a single-pixel detector.

    PubMed

    Gordon, George S D; Feng, Feng; Kang, Qiongyue; Jung, Yongmin; Sahu, Jayanta; Wilkinson, Timothy

    2014-10-15

    A novel imaging technique that produces accurate amplitude and phase images of an optical fiber facet using only a phase-only liquid-crystal on silicon (LCOS) spatial light modulator (SLM) and a single-pixel detector is presented. The system can take images in two orthogonal polarizations and so provides a powerful tool for modal characterization of multimode fibers, which is of increasing importance due to their burgeoning use in telecommunications and medical applications. This technique first uses a simulated annealing algorithm to compute a hologram that collects light from a small region of the fiber facet. Next, the fiber facet is automatically brought into focus using adaptive aberration correction on the SLM. Finally, a common-path interferometer is created using the SLM, and the phase of the optical field at each pixel is determined. Finally, high-definition amplitude and phase images of a ring-core refractive index fiber are presented as a proof-of-principle demonstration of the technique. PMID:25361149

  15. Characterisation of micro-strip and pixel silicon detectors before and after hadron irradiation

    NASA Astrophysics Data System (ADS)

    Allport, P. P.; Ball, K.; Casse, G.; Chmill, V.; Forshaw, D.; Hadfield, K.; Pritchard, A.; Pool, P.; Tsurin, I.

    2012-01-01

    The use of segmented silicon detectors for tracking and vertexing in particle physics has grown substantially since their introduction in 1980. It is now anticipated that roughly 50,000 six inch wafers of high resistivity silicon will need to be processed into sensors to be deployed in the upgraded experiments in the future high luminosity LHC (HL-LHC) at CERN. These detectors will also face an extremely severe radiation environment, varying with distance from the interaction point. The volume of required sensors is large and their delivery is required during a relatively short time, demanding a high throughput from the chosen suppliers. The current situation internationally, in this highly specialist market, means that security of supply for large orders can therefore be an issue and bringing additional potential vendors into the field can only be an advantage. Semiconductor companies that could include planar sensors suitable for particle physics in their product lines will, however, need to prove their products meet all the stringent technical requirements. A semiconductor company with very widespread experience of producing science grade CCDs (including deep depletion devices) has adapted their CCD process to fabricate for the first time several wafers of pixel and micro-strip radiation hard sensors, suitable for future high energy physics experiments. The results of the pre-irradiation characterization of devices fabricated with different processing parameters and the measurements of charge collection properties after different hadron irradiation doses up to those anticipated for the (larger area) outer pixel layers at the high-luminosity LHC (HL-LHC) are presented and compared with results from more established particle physics suppliers.

  16. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Zhao, C.; Konstantinidis, A. C.; Zheng, Y.; Anaxagoras, T.; Speller, R. D.; Kanicki, J.

    2015-12-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm-1 and a DQE of around 0.5 at spatial frequencies  <1 mm-1. In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNRi) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (~1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered.

  17. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis.

    PubMed

    Zhao, C; Konstantinidis, A C; Zheng, Y; Anaxagoras, T; Speller, R D; Kanicki, J

    2015-12-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm(-1) and a DQE of around 0.5 at spatial frequencies  <1 mm(-1). In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNRi) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (~1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered. PMID:26540090

  18. Reduction of ring artifacts in CBCT: Detection and correction of pixel gain variations in flat panel detectors

    SciTech Connect

    Altunbas, Cem; Lai, Chao-Jen; Zhong, Yuncheng; Shaw, Chris C.

    2014-09-15

    Purpose: In using flat panel detectors (FPD) for cone beam computed tomography (CBCT), pixel gain variations may lead to structured nonuniformities in projections and ring artifacts in CBCT images. Such gain variations can be caused by change in detector entrance exposure levels or beam hardening, and they are not accounted by conventional flat field correction methods. In this work, the authors presented a method to identify isolated pixel clusters that exhibit gain variations and proposed a pixel gain correction (PGC) method to suppress both beam hardening and exposure level dependent gain variations. Methods: To modulate both beam spectrum and entrance exposure, flood field FPD projections were acquired using beam filters with varying thicknesses. “Ideal” pixel values were estimated by performing polynomial fits in both raw and flat field corrected projections. Residuals were calculated by taking the difference between measured and ideal pixel values to identify clustered image and FPD artifacts in flat field corrected and raw images, respectively. To correct clustered image artifacts, the ratio of ideal to measured pixel values in filtered images were utilized as pixel-specific gain correction factors, referred as PGC method, and they were tabulated as a function of pixel value in a look-up table. Results: 0.035% of detector pixels lead to clustered image artifacts in flat field corrected projections, where 80% of these pixels were traced back and linked to artifacts in the FPD. The performance of PGC method was tested in variety of imaging conditions and phantoms. The PGC method reduced clustered image artifacts and fixed pattern noise in projections, and ring artifacts in CBCT images. Conclusions: Clustered projection image artifacts that lead to ring artifacts in CBCT can be better identified with our artifact detection approach. When compared to the conventional flat field correction method, the proposed PGC method enables characterization of nonlinear

  19. Beam test results of the dependence of signal size on incident particle flux in diamond pixel and pad detectors

    NASA Astrophysics Data System (ADS)

    Wallny, R.

    2015-07-01

    We present results of beam tests of charged particle detectors based on single-crystal and poly-crystalline Chemical Vapor Deposition (CVD) diamond. We measured the signal pulse height dependence on the particle flux. The detectors were tested over a range of particle fluxes from 2 kHz/cm2 to 20 MHz/cm2. The pulse height of the sensors was measured with pad and pixel readout electronics. The pulse height of the non-irradiated single-crystal CVD diamond pad sensors was stable with respect to flux, while the pulse height of irradiated single-crystal CVD diamond pad sensors decreased with increasing particle flux. The pulse height of the non-irradiated single-crystal CVD diamond pixel detectors decreased slightly with increasing particle flux while the pulse height of the irradiated single-crystal CVD diamond pixel detectors decreased significantly with increasing particle flux. The observed sensitivity to flux is similar in both the diamond pad sensors constructed using diamonds from the Pixel Luminosity Telescope (PLT) irradiated during its pilot run in the Compact Muon Solenoid (CMS) detector and in neutron irradiated diamond pad sensors from the same manufacturer irradiated to the same fluence of neutrons. The pulse height for irradiated poly-crystalline CVD diamond pad sensors proved to be stable with respect to particle flux.

  20. Pixel detector Timepix operated in pile-up mode for pulsed imaging with ultra-soft X-rays

    NASA Astrophysics Data System (ADS)

    Krejci, F.; Jakubek, J.; Kroupa, M.; Bruza, P.; Panek, D.

    2012-12-01

    The hybrid semiconductor pixel detector Timepix operated in the Time-over-Threshold mode (ToT) enables direct energy measurement in each pixel. The advantage of noiseless position sensitive detection combined with per pixel spectroscopic capability opens the way to numerous new applications, which were till now, however, restricted to detection of radiation which is basically above the detector energy threshold (typically 3-4 keV). This limitation excludes application of the hybrid pixel technology to highly interesting fields such as plasma diagnostics or X-ray microscopy. In this contribution we demonstrate how the Timepix detector working in ToT mode can be operated as a detector for particles which are in principle below the detector threshold, namely for soft X-ray photons with energy typically 0.5 keV. The approach is based on the detection of a larger number of photons incoming in the pixel signal processing chain in a time significantly shorter than the shaping time of the pixel electronics, i.e. forming signal pile-up. The proposed approach enables a CCD-like integrating operation with the many advantages of the hybrid counting technology (direct conversion, high sensitivity, dark-current free, room temperature operation, fully digital output and possibility to utilize various read-out architectures). Using the proposed approach we performed single-shot X-ray radiography with a laser-induced plasma source in the spectral region of water window. The same technique was used for the characterization of the source itself.

  1. Simultaneous, coincident 2-D ACAR and DBAR using segmented HPGe detectors incorporating sub-pixel interpolation

    NASA Astrophysics Data System (ADS)

    Williams, Christopher S.; Burggraf, Larry W.; Adamson, Paul E.; Petrosky, James C.; Oxley, Mark E.

    2010-04-01

    A three-dimensional Positron Annihilation Spectrometry System (3D PASS) for determination of 3D electron-positron (e--e+) momentum densities by measuring coincident annihilation photons was designed, constructed and characterized. 3D PASS collects a single data set including correlated photon energies and coincident photon positions which are typically collected separately by two-dimensional angular correlation of annihilation radiation (2D ACAR) and two-detector coincident Doppler broadening of annihilation radiation (CDBAR) spectrometry. 3D PASS is composed of two position-sensitive, high-purity germanium (HPGe) double-sided strip detectors (DSSD(s)) linked together by a 32-channel, 50 MHz digital electronics suite. The DSSDs data were analyzed to determine location of photon detection events using an interpolation method to achieve a spatial resolution less than the 5-mm width of the DSSDs' charge collection strips. The interpolation method relies on measuring a figure-of-merit proportional to the area of the transient charges observed on both strips directly adjacent to the charge collection strip detecting the full charge deposited by the annihilation photon. This sub-pixel resolution, corresponding to the error associated with event location within a sub-pixel was measured for both DSSDs using the approach outlined in Williams et al [1] and was on the order of ± 0.20 mm (± one-standard deviation). As a result of the sub-pixel resolution, the distance between the DSSDs and material sample was reduced by a factor of five compared to what is typically required in 2D ACAR systems was necessary to achieve 0.5-mrad angular resolution. This reduction in the system's footprint decreases attenuation of the annihilation photons in the air between the material sample and the DSSDs and increases the solid angle between the sample and the DSSDs, ultimately resulting in higher system detection efficiency. 3D PASS was characterized in the same manner comparable to state

  2. Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.

    PubMed

    Jungmann, Julia H; Heeren, Ron M A

    2013-01-15

    Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. PMID:23239313

  3. Design, simulation, fabrication, and preliminary tests of 3D CMS pixel detectors for the super-LHC

    SciTech Connect

    Koybasi, Ozhan; Bortoletto, Daniela; Hansen, Thor-Erik; Kok, Angela; Hansen, Trond Andreas; Lietaer, Nicolas; Jensen, Geir Uri; Summanwar, Anand; Bolla, Gino; Kwan, Simon Wing Lok; /Fermilab

    2010-01-01

    The Super-LHC upgrade puts strong demands on the radiation hardness of the innermost tracking detectors of the CMS, which cannot be fulfilled with any conventional planar detector design. The so-called 3D detector architectures, which feature columnar electrodes passing through the substrate thickness, are under investigation as a potential solution for the closest operation points to the beams, where the radiation fluence is estimated to reach 10{sup 16} n{sub eq}/cm{sup 2}. Two different 3D detector designs with CMS pixel readout electronics are being developed and evaluated for their advantages and drawbacks. The fabrication of full-3D active edge CMS pixel devices with p-type substrate has been successfully completed at SINTEF. In this paper, we study the expected post-irradiation behaviors of these devices with simulations and, after a brief description of their fabrication, we report the first leakage current measurement results as performed on wafer.

  4. A vertically integrated pixel readout device for the Vertex Detector at the International Linear Collider

    SciTech Connect

    Deptuch, Grzegorz; Christian, David; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab

    2008-12-01

    3D-Integrated Circuit technology enables higher densities of electronic circuitry per unit area without the use of nanoscale processes. It is advantageous for mixed mode design with precise analog circuitry because processes with conservative feature sizes typically present lower process dispersions and tolerate higher power supply voltages, resulting in larger separation of a signal from the noise floor. Heterogeneous wafers (different foundries or different process families) may be combined with some 3D integration methods, leading to the optimization of each tier in the 3D stack. Tracking and vertexing in future High-Energy Physics (HEP) experiments involves construction of detectors composed of up to a few billions of channels. Readout electronics must record the position and time of each measurement with the highest achievable precision. This paper reviews a prototype of the first 3D readout chip for HEP, designed for a vertex detector at the International Linear Collider. The prototype features 20 x 20 {micro}m{sup 2} pixels, laid out in an array of 64 x 64 elements and was fabricated in a 3-tier 0.18 {micro}m Fully Depleted SOI CMOS process at MIT-Lincoln Laboratory. The tests showed correct functional operation of the structure. The chip performs a zero-suppressed readout. Successive submissions are planned in a commercial 3D bulk 0.13 {micro}m CMOS process to overcome some of the disadvantages of an FDSOI process.

  5. Unconventional XAS applications in Physical Science using Pixel Array X-ray Detector

    NASA Astrophysics Data System (ADS)

    Oyanagi, Hiroyuki

    2007-03-01

    Fluorescence x-ray yield is a conventional technique which increases sensitivity of x-ray absorption spectroscopy (XAS). Combining high brilliance x-ray sources and state-of-the-art pixel array detector (PAD) opened up unconventional application channels in condensed matter science. PAD is a segmented detector fabricated onto a mono domain single crystal by lithography. Our Ge PAD consists of 10×10 segments with almost 100% packing ratio. The local structure of photo-induced phase transition of Fe(II) spin-crossover complex under visible light irradiation was studied. We find that the coordination symmetry is retained upon the diamagnetic (S=0)↔paramagnetic (S=2) transformation. In the application to high-temperature superconducting (La,Sr)2CuO4 thin film single crystals, the EXAFS results show that the local structure (CuO6 octahedron) is tetragonally deformed in accordance with the epitaxial strain. High-quality data without the effect of substrates were obtained by real-time monitoring segmented fluorescence signals.

  6. Radiation-hard active CMOS pixel sensors for HL-LHC detector upgrades

    NASA Astrophysics Data System (ADS)

    Backhaus, Malte

    2015-02-01

    The luminosity of the Large Hadron Collider (LHC) will be increased during the Long Shutdown of 2022 and 2023 (LS3) in order to increase the sensitivity of its experiments. A completely new inner detector for the ATLAS experiment needs to be developed to withstand the extremely harsh environment of the upgraded, so-called High-Luminosity LHC (HL-LHC). High radiation hardness as well as granularity is mandatory to cope with the requirements in terms of radiation damage as well as particle occupancy. A new silicon detector concept that uses commercial high voltage and/or high resistivity full complementary metal-oxide-semiconductor (CMOS) processes as active sensor for pixel and/or strip layers has risen high attention, because it potentially provides high radiation hardness and granularity and at the same time reduced price due to the commercial processing and possibly relaxed requirements for the hybridization technique. Results on the first prototypes characterized in a variety of laboratory as well as test beam environments are presented.

  7. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    NASA Astrophysics Data System (ADS)

    Annovazzi, A.; Amendolia, S. R.; Bigongiari, A.; Bisogni, M. G.; Catarsi, F.; Cesqui, F.; Cetronio, A.; Colombo, F.; Delogu, P.; Fantacci, M. E.; Gilberti, A.; Lanzieri, C.; Lavagna, S.; Novelli, M.; Passuello, G.; Paternoster, G.; Pieracci, M.; Poletti, M.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Testa, A.; Venturelli, L.

    2007-06-01

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm 2 therefore to cover the typical irradiation field used in mammography (18×24 cm 2), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma "La Sapienza", Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%.

  8. Linear fitting of multi-threshold counting data with a pixel-array detector for spectral X-ray imaging

    PubMed Central

    Muir, Ryan D.; Pogranichney, Nicholas R.; Muir, J. Lewis; Sullivan, Shane Z.; Battaile, Kevin P.; Mulichak, Anne M.; Toth, Scott J.; Keefe, Lisa J.; Simpson, Garth J.

    2014-01-01

    Experiments and modeling are described to perform spectral fitting of multi-threshold counting measurements on a pixel-array detector. An analytical model was developed for describing the probability density function of detected voltage in X-ray photon-counting arrays, utilizing fractional photon counting to account for edge/corner effects from voltage plumes that spread across multiple pixels. Each pixel was mathematically calibrated by fitting the detected voltage distributions to the model at both 13.5 keV and 15.0 keV X-ray energies. The model and established pixel responses were then exploited to statistically recover images of X-ray intensity as a function of X-ray energy in a simulated multi-wavelength and multi-counting threshold experiment. PMID:25178010

  9. Study of UT glasses for pixel identification performance in multi-anode PMT-based detectors for PET

    NASA Astrophysics Data System (ADS)

    Straub, K.; Belcari, N.; Camarlinghi, N.; Ferretti, S.; Marino, N.; Rosso, V.; Sportelli, G.; Del Guerra, A.

    2013-08-01

    The pixel identification capability is a common problem of detector systems consisting of scintillating matrices coupled to photodetectors. In positron emission tomography (PET) systems, a better pixel identification leads directly to an improvement of the spatial resolution of the system. To gain pixel identification efficiency especially at the peripheral active area, ultra-transmitting (UT) glasses can be inserted between the crystal and PMT array in order to promote light spread and avoid overlap of responses due to the enhanced light spread. Measurements with three different UT glass thicknesses (d = 0.7 , 1.0 and 1.35 mm) have been performed in order to study their impact on pixel identification properties compared to direct coupling.

  10. GEM400: A front-end chip based on capacitor-switch array for pixel-based GEM detector

    NASA Astrophysics Data System (ADS)

    Li, H. S.; Jiang, X. S.; Liu, G.; Wang, N.; Sheng, H. Y.; Zhuang, B. A.; Zhao, J. W.

    2012-03-01

    The upgrade of Beijing Synchrotron Radiation Facility (BSRF) needs two-dimensional position-sensitive detection equipment to improve the experimental performance. Gas Electron Multiplier (GEM) detector, in particular, pixel-based GEM detector has good application prospects in the domain of synchrotron radiation. The read-out of larger scale pixel-based GEM detector is difficult for the high density of the pixels (PAD for collecting electrons). In order to reduce the number of cables, this paper presents a read-out scheme for pixel-based GEM detector, which is based on System-in-Package technology and ASIC technology. We proposed a circuit structure based on capacitor switch array circuit, and design a chip GEM400, which is a 400 channels ASIC. The proposed circuit can achieve good stability and low power dissipation. The chip is implemented in a 0.35μm CMOS process. The basic functional circuitry in ths chip includes analog switch, analog buffer, voltage amplifier, bandgap and control logic block, and the layout of this chip takes 5mm × 5mm area. The simulation results show that the chip can allow the maximum amount of input charge 70pC on the condition of 100pF external integrator capacitor. Besides, the chip has good channel uniformity (INL is better than 0.1%) and lower power dissipation.