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Sample records for barrier si detector

  1. Al/Au/n-Si/Al surface barrier detector

    International Nuclear Information System (INIS)

    Charged-particle detectors are required to be operated sometimes in ambient light for applications like alpha counting and range finding. Detectors like Al/p-Si surface barrier with aluminium on the front side are found quite suitable. Gold/n-Si surface barrier detectors are not usable because of their excessive background photo current. These detectors, we fabricate for use in nuclear experiments, were given an aluminium coating on their gold side for use in room light. The Au/n-Si/Al surface barrier diodes were characterized for their electrical properties and performance as alpha detectors. Detectors showing good energy resolution (∼ 50 KeV) were selected and provided with another thin reflecting coat of aluminium on their front sides

  2. Schottky barrier detectors on 4H-SiC n-type epitaxial layer for alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, S.K.; Krishna, R.M.; Zavalla, K.J. [Department of Electrical Engineering, University of South Carolina, Columbia, SC 29208 (United States); Mandal, K.C., E-mail: mandalk@cec.sc.edu [Department of Electrical Engineering, University of South Carolina, Columbia, SC 29208 (United States)

    2013-02-11

    Schottky barrier detectors have been fabricated on 50 μm n-type 4H-SiC epitaxial layers grown on 360 μm SiC substrates by depositing ∼10 nm nickel contact. Current–voltage (I–V) and capacitance–voltage (C–V) measurements were carried out to investigate the Schottky barrier properties. The detectors were evaluated for alpha particle detection using a {sup 241}Am alpha source. An energy resolution of ∼2.7% was obtained with a reverse bias of 100 V for 5.48 MeV alpha particles. The measured charge collection efficiency (CCE) was seen to vary as a function of bias voltage following a minority carrier diffusion model. Using this model, a diffusion length of∼3.5 μm for holes was numerically calculated from the CCE vs. bias voltage plot. Rise-time measurements of digitally recorded charge pulses for the 5.48 MeV alpha particles showed a presence of two sets of events having different rise-times at a higher bias of 200 V. A biparametric correlation scheme was successfully implemented for the first time to visualize the correlated pulse-height distribution of the events with different rise-times. Using the rise-time measurements and the biparametric plots, the observed variation of energy resolution with applied bias was explained.

  3. Complementary barrier infrared detector (CBIRD)

    Science.gov (United States)

    Ting, David Z. (Inventor); Bandara, Sumith V. (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2013-01-01

    An infrared detector having a hole barrier region adjacent to one side of an absorber region, an electron barrier region adjacent to the other side of the absorber region, and a semiconductor adjacent to the electron barrier.

  4. Barrier infrared detector

    Science.gov (United States)

    Ting, David Z. (Inventor); Khoshakhlagh, Arezou (Inventor); Soibel, Alexander (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2012-01-01

    A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be "chirped" (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

  5. External quantum efficiency-enhanced PtSi Schottky-barrier detector utilizing plasmonic ZnO:Al nanoparticles and subwavelength gratings

    Institute of Scientific and Technical Information of China (English)

    Bingxin Kang; Yi Cai; Lingxue Wang

    2016-01-01

    A infrared light trapping structure combining front subwavelength gratings and rear ZnO:Al nanoparticles for a PtSi Schottky-barrier detector over a 3-5 μm waveband is theoretically investigated.By selecting the proper plasmonic material and optimizing the parameters for the proposed structure,the absorption of the PtSi layer is dramatically improved.The theoretical results show that this improvement eventually translates into an equivalent external quantum efficiency (EQE) enhancement of 2.46 times at 3-3.6 μm and 2.38 times at 3.6-5 μm compared to conventional structures.This improvement in the EQE mainly lies in the increase of light path lengths within the PtSi layer by the subwavelength grating diffraction and nanoparticle-scattering effects.

  6. HgCdTe barrier infrared detectors

    Science.gov (United States)

    Kopytko, M.; Rogalski, A.

    2016-05-01

    In the last decade, new strategies to achieve high-operating temperature (HOT) detectors have been proposed, including barrier structures such as nBn devices, unipolar barrier photodiodes, and multistage (cascade) infrared detectors. The ability to tune the positions of the conduction and valence band edges independently in a broken-gap type-II superlattices is especially helpful in the design of unipolar barriers. This idea has been also implemented in HgCdTe ternary material system. However, the implementation of this detector structure in HgCdTe material system is not straightforward due to the existence of a valence band discontinuity (barrier) at the absorber-barrier interface. In this paper we present status of HgCdTe barrier detectors with emphasis on technological progress in fabrication of MOCVD-grown HgCdTe barrier detectors achieved recently at the Institute of Applied Physics, Military University of Technology. Their performance is comparable with state-of-the-art of HgCdTe photodiodes. From the perspective of device fabrication their important technological advantage results from less stringent surface passivation requirements and tolerance to threading dislocations.

  7. Detectors for proton counting. Si-APD and scintillation detectors

    International Nuclear Information System (INIS)

    Increased intensity of synchrotron radiation requests users to prepare photon pulse detectors having higher counting rates. As detectors for photon counting, silicon-avalanche photodiode (Si-APD) and scintillation detectors were chosen for the fifth series of detectors. Principle of photon detection by pulse and need of amplification function of the detector were described. Structure and working principle, high counting rate measurement system, bunch of electrons vs. counting rate, application example of NMR time spectroscopy measurement and comments for users were described for the Si-APD detector. Structure of scintillator and photomultiplier tube, characteristics of scintillator and performance of detector were shown for the NaI detector. Future development of photon pulse detectors was discussed. (T. Tanaka)

  8. Complementary Barrier Infrared Detector (CBIRD) Contact Methods

    Science.gov (United States)

    Ting, David Z.; Hill, Cory J.; Gunapala, Sarath D.

    2013-01-01

    The performance of the CBIRD detector is enhanced by using new device contacting methods that have been developed. The detector structure features a narrow gap adsorber sandwiched between a pair of complementary, unipolar barriers that are, in turn, surrounded by contact layers. In this innovation, the contact adjacent to the hole barrier is doped n-type, while the contact adjacent to the electron barrier is doped p-type. The contact layers can have wider bandgaps than the adsorber layer, so long as good electrical contacts are made to them. If good electrical contacts are made to either (or both) of the barriers, then one could contact the barrier(s) directly, obviating the need for additional contact layers. Both the left and right contacts can be doped either n-type or ptype. Having an n-type contact layer next to the electron barrier creates a second p-n junction (the first being the one between the hole barrier and the adsorber) over which applied bias could drop. This reduces the voltage drop over the adsorber, thereby reducing dark current generation in the adsorber region.

  9. Doping-Spike PtSi Schottky Infrared Detectors with Extended Cutoff Wavelengths

    Science.gov (United States)

    Lin, T. L.; Park, J. S.; Gunapala, S. D.; Jones, E. W.; Castillo, H. M. Del

    1994-01-01

    A technique incorporating a p+ doping spike at the silicide/Si interface to reduce the effective Schottky barrier of the silicide infrared detectors and thus extend the cutoff wavelength has been developed.

  10. Schottky Barrier CdTe(Cl) Detectors for Planetary Missions

    Science.gov (United States)

    Eisen, Yosef; Floyd, Samuel

    2002-10-01

    Schottky barrier cadmium telluride (CdTe) radiation detectors of dimensions 2mm × 2mm × 1mm and segmented monolithic 3cm × 3 cm × 1mm are under study at GSFC for future NASA planetary instruments. These instruments will perform x-ray fluorescence spectrometry of the surface and monitor the solar x-ray flux spectrum, the excitation source for the characteristic x-rays emitted from the planetary body. The Near Earth Asteroid Rendezvous (NEAR) mission is the most recent example of such a remote sensing technique. Its x-ray fluorescence detectors were gas proportional counters with a back up Si PIN solar monitor. Analysis of NEAR data has shown the necessity to develop a solar x-ray detector with efficiency extending to 30keV. Proportional counters and Si diodes have low sensitivity above 9keV. Our 2mm × 2mm × 1mm CdTe operating at -30°C possesses an energy resolution of 250eV FWHM for 55Fe with unit efficiency to up to 30keV. This is an excellent candidate for a solar monitor. Another ramification of the NEAR data is a need to develop a large area detector system, 20-30 cm2, with cosmic ray charged particle rejection, for measuring the characteristic radiation. A 3cm × 3cm × 1mm Schottky CdTe segmented monolithic detector is under investigation for this purpose. A tiling of 2-3 such detectors will result in the desired area. The favorable characteristics of Schottky CdTe detectors, the system design complexities when using CdTe and its adaptation to future missions will be discussed.

  11. Development of dual-band barrier detectors

    Science.gov (United States)

    Plis, Elena; Myers, Stephen A.; Ramirez, David A.; Krishna, Sanjay

    2016-05-01

    We report on the development of dual-band InAs/GaSb type-II strained layer superlattices (T2SL) detectors with barrier designs at SK Infrared. Over the past five years, we demonstrated mid-wave/long-wave (MW/LWIR, cut-off wavelengths are 5 μm and 10.0 μm), and LW/LWIR (cut-off wavelengths are 9 μm and 11.0 μm) detectors with nBn and pBp designs. Recent results include a high performance bias-selectable long/long-wavelength infrared photodetector based on T2SL with a pBp barrier architecture. The two channels 50% cut-off wavelengths were ~ 9.2 μm and ~ 12 μm at 77 K. The "blue" and "red" LWIR absorbers demonstrated saturated QE values of 34 % and 28 %, respectively, measured in a backside illuminated configuration with a ~ 35 μm thick layer of residual GaSb substrate. Bulk-limited dark current levels were ~ 2.6 x 10-7 A/cm2 at + 100 mV and ~ 8.3 x 10-4 A/cm2 at - 200 mV for the "blue" and "red" channels, respectively.

  12. Application of pulse shape discrimination in Si detector for fission fragment angular distribution measurements

    Indian Academy of Sciences (India)

    B K Nayak; E T Mirgule; R K Choudhury

    2005-12-01

    Pulse shape discrimination (PSD) with totally depleted transmission type Si surface barrier detector in reverse mount has been investigated to identify fission fragments in the presence of elastic background in heavy ion-induced fission reactions by both numerical simulation and experimental studies. The PSD method is compared with the other conventional methods adopted to identify fission fragments with solid-state detectors such as - telescope and single thin detector and the data for the 10B + 232Th fission reaction are presented. Results demonstrate the usefulness of a single transmission-type surface barrier detector for the identification of fission fragments and projectiles like heavy ions.

  13. Development of Si (Li) detectors for charged particles spectrometer

    CERN Document Server

    Onabe, H; Obinata, M; Kashiwagi, T

    2002-01-01

    Lithium drifted silicon (Si (Li)) detectors with high-quality large area for charged particles spectrometer abroad artificial satellite have been developed. Surface stability can be obtained by thin p-n junction fabricated with the applied photo engraving process (PEP) instead of surface barrier. The region compensated with Lithium can be improved by the adequate heat treatment, and this improvement can be monitored by means of a combination of copper plating and subsequent micro-XRF analysis. The detectors fabricated from the thermal treated wafers were found to have better energy resolution both for alpha-particles from sup 2 sup 4 sup 1 Am and conversion electrons from sup 2 sup 0 sup 7 Bi. (author)

  14. Correlation of DT and DD fusion neutron damage in silicon surface barrier detector

    International Nuclear Information System (INIS)

    In order to examine the correlation of DT and DD fusion neutron damage in Si, a silicon surface barrier detector (Si-SBD) was irradiation with neutrons from a deuteron accelerator. The leakage current increased proportionally with neutron fluence, which determined the neutron damage constant for the Si-SBD. The correlation factor of the DT and DD neutron damage in the Si-SBD was determined from the ratio of the DT and DD neutron damage constants and was found to be 2.3. We also calculated the rate of DT and DD neutron displacement damage for Si by using the TRIM-90 computer program and actual data on neutron reactions in the Si-SBD. The correlation factor of DT and DD neutron damage from the calculation agreed with that from the Si-SBD irradiation experiment. (author)

  15. Effect of Si/Si1-yCy/Si Barriers on the Characteristics of Si1-xGex/Si Resonant Tunneling Structures

    Institute of Scientific and Technical Information of China (English)

    HAN Ping; CHENG Xue-Mei; Masao Sakuraba; YoungCheon Jeong; Takashi Matsuura; Junichi Murota

    2000-01-01

    P-type double barrier resonant tunneling diodes (RTD) with the single Si0.6Ge0.4 quantum well and double Si0.6 Ge0.4 spacer have been realized by using an ultra clean low-pressure chemical vapor deposition system. The effect of Si1-yCy layer on the characteristics of the devices was shown by comparing the current-voltage (Ⅰ-Ⅴ) characteristics of RTD's of the barriers of Si layers with that of Si/Si1-yCy/Si structures. The peak voltage was gradually increased and the resonant current decreased obviously with increasing C content in the Si/Si1-yCy/Si barriers. The origin of the phenomena above can be attributed to the C related deep acceptor levels in the Si/Si1-yCy/Si barriers. The possible mechanism for the observed Ⅰ-Ⅴcharacteristics was shown more clearly by increasing C content to 3% and changing the thicknesses of Si and Si1-yCy layers in the Si/Si1-yCy/Si barriers.

  16. High Operating Temperature Barrier Infrared Detector with Tailorable Cutoff Wavelength

    Science.gov (United States)

    Ting, David Z. (Inventor); Hill, Cory J. (Inventor); Seibel, Alexander (Inventor); Bandara, Sumith Y. (Inventor); Gunapala, Sarath D. (Inventor)

    2015-01-01

    A barrier infrared detector with absorber materials having selectable cutoff wavelengths and its method of manufacture is described. A GaInAsSb absorber layer may be grown on a GaSb substrate layer formed by mixing GaSb and InAsSb by an absorber mixing ratio. A GaAlAsSb barrier layer may then be grown on the barrier layer formed by mixing GaSb and AlSbAs by a barrier mixing ratio. The absorber mixing ratio may be selected to adjust a band gap of the absorber layer and thereby determine a cutoff wavelength for the barrier infrared detector. The absorber mixing ratio may vary along an absorber layer growth direction. Various contact layer architectures may be used. In addition, a top contact layer may be isolated into an array of elements electrically isolated as individual functional detectors that may be used in a detector array, imaging array, or focal plane array.

  17. Complementary Barrier Infrared Detector (CBIRD) with Double Tunnel Junction Contact and Quantum Dot Barrier Infrared Detector (QD-BIRD)

    Science.gov (United States)

    Ting, David Z.-Y; Soibel, Alexander; Khoshakhlagh, Arezou; Keo, Sam A.; Nguyen, Jean; Hoglund, Linda; Mumolo, Jason M.; Liu, John K.; Rafol, Sir B.; Hill, Cory J.; Gunapala, Sarath D.

    2012-01-01

    The InAs/GaSb type-II superlattice based complementary barrier infrared detector (CBIRD) has already demonstrated very good performance in long-wavelength infrared (LWIR) detection. In this work, we describe results on a modified CBIRD device that incorporates a double tunnel junction contact designed for robust device and focal plane array processing. The new device also exhibited reduced turn-on voltage. We also report results on the quantum dot barrier infrared detector (QD-BIRD). By incorporating self-assembled InSb quantum dots into the InAsSb absorber of the standard nBn detector structure, the QD-BIRD extend the detector cutoff wavelength from approximately 4.2 micrometers to 6 micrometers, allowing the coverage of the mid-wavelength infrared (MWIR) transmission window. The device has been observed to show infrared response at 225 K.

  18. Fusion of Si28+Si28,30: Different trends at sub-barrier energies

    Science.gov (United States)

    Montagnoli, G.; Stefanini, A. M.; Esbensen, H.; Jiang, C. L.; Corradi, L.; Courtin, S.; Fioretto, E.; Grebosz, J.; Haas, F.; Jia, H. M.; Mazzocco, M.; Michelagnoli, C.; Mijatović, T.; Montanari, D.; Parascandolo, C.; Scarlassara, F.; Strano, E.; Szilner, S.; Torresi, D.

    2014-10-01

    Background: The fusion excitation function of the system Si28+Si28 at energies near and below the Coulomb barrier is known only down to ≃15 mb. This precludes any information on both coupling effects on sub-barrier cross sections and the possible appearance of hindrance. For Si28+Si30 even if the fusion cross section is measured down to ≃50 μb, the evidence of hindrance is marginal. Both systems have positive fusion Q values. While Si28 has a deformed oblate shape, Si30 is spherical. Purpose: We investigate 1. the possible influence of the different structure of the two Si isotopes on the fusion excitation functions in the deep sub-barrier region and 2. whether hindrance exists in the Si+Si systems and whether it is strong enough to generate an S-factor maximum, thus allowing a comparison with lighter heavy-ion systems of astrophysical interest. Methods: Si28 beams from the XTU Tandem accelerator of the INFN Laboratori Nazionali di Legnaro were used. The setup was based on an electrostatic beam separator, and fusion evaporation residues (ER) were detected at very forward angles. Angular distributions of ER were measured. Results: Fusion cross sections of Si28+Si28 have been obtained down to ≃600 nb. The slope of the excitation function has a clear irregularity below the barrier, but no indication of a S-factor maximum is found. For Si28+Si30 the previous data have been confirmed and two smaller cross sections have been measured down to ≃4 μb. The trend of the S-factor reinforces the previous weak evidence of hindrance. Conclusions: The sub-barrier cross sections for Si28+Si28 are overestimated by coupled-channels calculations based on a standard Woods-Saxon potential, except for the lowest energies. Calculations using the M3Y+repulsion potential are adjusted to fit the Si28+Si28 and the existing Si30+Si30 data. An additional weak imaginary potential (probably simulating the effect of the oblate Si28 deformation) is required to fit the low-energy trend of

  19. Two-dimensional position sensitive Si(Li) detector

    International Nuclear Information System (INIS)

    Circular, large-area two-dimensional Si(Li) position sensitive detectors have been fabricated. The detectors employ a thin lithium-diffused n+ resisitive layer for one contact and a boron implanted p+ resistive layer for the second contact. A position resolution of the order of 100 μm is indicated

  20. Si strip detector with integrated coupling capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Caccia, M.; Evensen, L.; Hansen, T.E.; Horisberger, R.; Hubbeling, L.; Peisert, A.; Tuuva, T.; Weilhammer, P.; Zalewska, A.

    1987-10-01

    A silicon microstrip detector with capacitive coupling of the diode strips to the metallization and with individual polysilicon resistors to each diode has been developed. The detector was tested in a minimum ionizing particle beam showing a performance similar to conventional strip detectors and a spatial resolution of 3.5 ..mu..m. Capacitive coupling allows the decoupling of the leakage current from the input to the charge sensitive preamplifier especially in the case of LSI electronics.

  1. Surface Leakage Mechanisms in III-V Infrared Barrier Detectors

    Science.gov (United States)

    Sidor, D. E.; Savich, G. R.; Wicks, G. W.

    2016-09-01

    Infrared detector epitaxial structures employing unipolar barriers exhibit greatly reduced dark currents compared to simple pn-based structures. When correctly positioned within the structure, unipolar barriers are highly effective at blocking bulk dark current mechanisms. Unipolar barriers are also effective at suppressing surface leakage current in infrared detector structures employing absorbing layers that possess the same conductivity type in their bulk and at their surface. When an absorbing layer possesses opposite conductivity types in its bulk and at its surface, unipolar barriers are not solutions to surface leakage. This work reviews empirically determined surface band alignments of III-V semiconductor compounds and modeled surface band alignments of both gallium-free and gallium-containing type-II strained layer superlattice material systems. Surface band alignments are used to predict surface conductivity types in several detector structures, and the relationship between surface and bulk conductivity types in the absorbing layers of these structures is used as the basis for explaining observed surface leakage characteristics.

  2. 4H-SiC detectors for ultraviolet light monitoring

    Science.gov (United States)

    Mazzillo, M.; Sciuto, A.; Badalà, P.; Carbone, B.; Russo, A.; Coffa, S.

    2015-02-01

    Silicon Carbide (SiC) provides the unique property of near-perfect visible blindness and very high signal-to-noise ratio due to the high quantum efficiency and low dark current even at high temperature. These features make SiC the best available material for the manufacturing of visible blind semiconductor ultraviolet (UV) light detectors. Thanks to their properties, SiC detectors have been extensively used in fact for flame detection monitoring, UV sterilization and astronomy. Here we report on the electrical and optical performance of patterned thin metal film NiSi/4H-SiC vertical Schottky photodiodes with different semiconductor exposed area suitably designed for UV light monitoring.

  3. Thermal stability of Nb-Si-N and Ta-Si-N as diffusion barriers between Cu and Si

    International Nuclear Information System (INIS)

    In this study, Nb-Si-N and Ta-Si-N films were deposited on (100)Si wafers using a reactive sputtering technique and their thermal stability indispensable for a barrier metal against Cu was investigated using sheet resistance measurement, X-ray diffraction, and Auger electron spectroscopy depth profiling. The N2/Ar gas flow ratio for the sputter deposition of the Nb-Si-N and Ta-Si-N films with the highest thermal stability were found to be 5 % and 15 %, respectively. The Nb-Si-N film failed at 700 .deg. C, while the Ta-Si-N film failed at 900 .deg. C. the failure mechanism of the Nb-Si-N was found to be as follows : Cu atoms move to the Nb-Si-N/Si interface through the Nb-Si-N film and react with Si atoms in the Si substrate resulting in the formation of Cu3Si at the Nb-Si-N/Si interface. Also the failure mechanism of Ta-Si-N was found to be nearly the same as that of Nb-Si-N

  4. Nitrogen doping effect upon hole tunneling characteristics of Si barriers in Si1-xGex/Si resonant tunneling diode

    International Nuclear Information System (INIS)

    Nitrogen atomic-layer (N AL) doping effects upon hole tunneling characteristics of double 4 nm-thick Si barriers in the strained Si1−xGex/Si(100) hole resonant tunneling diode (RTD) were investigated. At a Si cap layer on Si1−xGex(100) (x = 0.2 and 0.4) formed at 500 °C, it was found that NH3 reaction was drastically enhanced at 500 °C especially at the Si cap layer thickness less than 0.5 nm, and the fact indicates a possibility of significant intermixing at the Si/Si1−xGex heterointerface. From current–voltage characteristics of the RTDs, drastic current suppression by N AL doping in the Si barriers can be observed with typical degree of current suppression as high as 103–105 at − 10 mV. Moreover, it was found that N AL doping influences, not only upon such current suppression, but slightly upon negative differential conductance characteristics. - Highlights: • NH3 reaction enhancement on a thin Si cap layer on Si1−xGex(100). • Drastic current suppression by N atomic-layer doping in Si barriers. • N atomic-layer doping effect upon negative differential conductance characteristics

  5. Radiation hardness characteristics of Si-PIN radiation detectors

    Science.gov (United States)

    Jeong, Manhee; Jo, Woo Jin; Kim, Han Soo; Ha, Jang Ho

    2015-06-01

    The Korea Atomic Energy Research Institute (KAERI) has fabricated Si-PIN radiation detectors with low leakage current, high resistivity (>11 kΩ cm) and low capacitance for high-energy physics and X-ray spectroscopy. Floating-zone (FZ) 6-in. diameter N-type silicon wafers, with crystal orientation and 675 μm thick, were used in the detector fabrication. The active areas are 3 mm×3 mm, 5 mm×5 mm and 10 mm×10 mm. We used a double deep-diffused structure at the edge of the active area for protection from the surface leakage path. We also compared the electrical performance of the Si-PIN detector with anti-reflective coating (ARC). For a detector with an active area of 3 mm×3 mm, the leakage current is about 1.9 nA and 7.4 nA at a 100 V reverse bias voltage, and 4.6 pF and 4.4 pF capacitance for the detector with and without an ARC, respectively. In addition, to compare the energy resolution in terms of radiation hardness, we measured the energy spectra with 57Co and 133Ba before the irradiation. Using developed preamplifiers (KAERI-PA1) that have ultra-low noise and high sensitivity, and a 3 mm×3 mm Si-PIN radiation detector, we obtained energy resolutions with 122 keV of 57Co and 81 keV of 133Ba of 0.221 keV and 0.261 keV, respectively. After 10, 100, 103, 104 and 105 Gy irradiation, we tested the characteristics of the radiation hardness on the Si-PIN radiation detectors in terms of electrical and energy spectra performance changes. The fabricated Si-PIN radiation detectors are working well under high dose irradiation conditions.

  6. Silicon surface-barrier nuclear-particle detectors

    International Nuclear Information System (INIS)

    Silicon surface-barrier detectors with sensitive areas of 25 mm2 and 1 cm2 have given a resolution of 13.5keV (FWHM) and 17keV, respectively, for alpha particles of 5.5 MeV. Detectors made from an entire ingot section and having a sensitive area of 2.6 cm2 have given a resolution of ∼ 1% which was limited by noise due to diode current. Barrier depths approaching 1 mm have been achieved using diodes made from 3500 Ω-cm n-type silicon with 1000-V bias. At 500 V the reverse current was -6 A/cm2. These barrier depths permit the detection of 10-MeV protons with good energy linearity. Silicon surface-barrier detectors have been used to measure electron, β, p, d, t, α, heavy-ion and fission-fragment energies. Fast-neutron spectrometry has been performed by using a Li6 radiator and a 4 π detector geometry. Thin silicon surface-barrier detectors suitable for dE/dX applications have been made with areas ranging from 1/10 to 2 cm2 and thicknesses down to 75 μ. Alpha-particle resolution of 22 keV is typical of 1/2-cm2 units, and the sensitive region can be extended to within approximately 10μ of the rear surface. An amplifier system has been designed specifically for use with silicon diode detectors to achieve the optimum pulse-height resolution. The noise with a capacitive load of 20 pF and 180pF on the amplifier input is ∼ 3.5 and 10keV, respectively. A built-in window amplifier allows a small portion of the pulse-height spectrum to be spread out over the entire capacity of multichannel pulse-height analyser. The system, including window amplifier, has a drift of < 300 eV/h and a line-voltage sensitivity of < 250 eV/line volt, when analysing a charge pulse on the input equivalent to 5.5 MeV. (author)

  7. A new configuration of the Moxon-Rae detector based on Si detector

    International Nuclear Information System (INIS)

    A new Moxon-Rae detector configuration based on Si semiconductor detector was proposed in this paper. Three γ-ray sources, 137Cs, 60Co, and 24Na, were employed to make actual measurements using the new Moxon-Rae detector. The measured pulse height spectra and detection efficiencies were compared with the EGS4 simulated values. The results revealed that the proposed new configuration is indeed a successful method and specially a useful technique for higher energy γ-ray measurement

  8. Superlattice Barrier Infrared Detector Development at the Jet Propulsion Laboratory

    Science.gov (United States)

    Ting, David Z.; Soibel, Alexander; Rafol, Sir B.; Nguyen, Jean; Hoglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Liu, John K.; Mumolo, Jason M.

    2011-01-01

    We report recent efforts in achieving state-of-the-art performance in type-II superlattice based infrared photodetectors using the barrier infrared detector architecture. We used photoluminescence measurements for evaluating detector material and studied the influence of the material quality on the intensity of the photoluminescence. We performed direct noise measurements of the superlattice detectors and demonstrated that while intrinsic 1/f noise is absent in superlattice heterodiode, side-wall leakage current can become a source of strong frequency-dependent noise. We developed an effective dry etching process for these complex antimonide-based superlattices that enabled us to fabricate single pixel devices as well as large format focal plane arrays. We describe the demonstration of a 1024x1024 pixel long-wavelength infrared focal plane array based the complementary barrier infrared detector (CBIRD) design. An 11.5 micron cutoff focal plane without anti-reflection coating has yielded noise equivalent differential temperature of 53 mK at operating temperature of 80 K, with 300 K background and cold-stop. Imaging results from a recent 10 ?m cutoff focal plane array are also presented.

  9. InGaAs Schottky barrier diode array detector for a real-time compact terahertz line scanner.

    Science.gov (United States)

    Han, Sang-Pil; Ko, Hyunsung; Park, Jeong-Woo; Kim, Namje; Yoon, Young-Jong; Shin, Jun-Hwan; Kim, Dae Yong; Lee, Dong Hun; Park, Kyung Hyun

    2013-11-01

    We present a terahertz (THz) broadband antenna-integrated 1 × 20 InGaAs Schottky barrier diode (SBD) array detector with an average responsivity of 98.5 V/W at a frequency of 250 GHz, which is measured without attaching external amplifiers and Si lenses, and an average noise equivalent power (NEP) of 106.6 pW/√Hz. The 3-dB bandwidth of the SBD detector is also investigated at approximately 180 GHz. For implementing an array-type SBD detector by a simple fabrication process to achieve a high yield, a structure comprising an SiN(x) layer instead of an air bridge between the anode and the cathode is designed. THz line beam imaging using a Gunn diode emitter with a center frequency of 250 GHz and a 1 × 20 SBD array detector is successfully demonstrated. PMID:24216813

  10. Spiral biasing adaptor for use in Si drift detectors and Si drift detector arrays

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng; Chen, Wei

    2016-07-05

    A drift detector array, preferably a silicon drift detector (SDD) array, that uses a low current biasing adaptor is disclosed. The biasing adaptor is customizable for any desired geometry of the drift detector single cell with minimum drift time of carriers. The biasing adaptor has spiral shaped ion-implants that generate the desired voltage profile. The biasing adaptor can be processed on the same wafer as the drift detector array and only one biasing adaptor chip/side is needed for one drift detector array to generate the voltage profiles on the front side and back side of the detector array.

  11. The SiD Detector for the International Linear Collider

    CERN Document Server

    ,

    2015-01-01

    The SiD Detector is one of two validated detector designs for the future International Linear Collider. SiD features a compact, cost-constrained design for precision Higgs couplings determination, and other measurements, and sensitivity to a wide range of possible new phenomena. A robust silicon vertex and tracking system, combined with a 5 Tesla central solenoidal field, provides excellent momentum resolution. The highly granular calorimeter system is optimized for Particle Flow application to achieve very good jet energy resolution over a wide range of energies. Details of the proposed implementation of the SiD subsystems, as driven by the physics requirements, will be given. The shared interaction point, push-pull mechanism, will be described, together with the estimated timeline for construction.

  12. Detection Simulation of SiC Semiconductor Detector

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hong Yeop; Kim, Jeong Dong; Lee, Yong Deok; Kim, Ho Dong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In a high radiation environment, it has received attention as a material for detecting radiation (neutron). As the field of application of a SIC neutron detector, the semiconductor detector used in cosmic rays was proposed by Ruddy. Recently, X-ray and low-energy gamma ray spectrometry with SiC detectors has been reported. Its usability has recently been being proved in neutron dose surveillance in BNCT (Boron-Capture Neutron Therapy), thermal neutron detection in a waste drum, nuclear material surveillance, and fast neutron detection. In addition, in 2006, an experiment was actually performed by Natsume on spent nuclear fuel. SIC is suitable for radiation surveillance in a complex radiation field emitted from spent nuclear fuel and the pyropocess process. In the radiation field of spent nuclear fuel, neutrons and gamma rays are generated. In this research, the performance of a SiC detector made at KAERI was evaluated to obtain a discriminated neutron signal. First, using neutron ({sup 252}Cf), alpha ({sup 241}Am), and gamma ({sup 60}Co) sources, a SiC semi- conductor detector was tested. The energy spectrum in a complex radiation field was simulated using the MCNPX 2.5. Finally, the experimental results by Ruddy were compared with the simulation results. Research result, whether the SiC semiconductor detector operating or not was confirmed through the simulation according to the neutron, gamma. The simulation results were similar to those of Ruddy. A further study is underway to investigate the discriminated neutron signal of a complex radiation field.

  13. Simulations of SiPM based scintillation detector for PANDA

    International Nuclear Information System (INIS)

    The Facility for Antiproton and Ion Research (FAIR) is a future project at GSI which will extend hadron physics studies up to the charm meson region using antiproton beams together with a state-of-the-art PANDA (acronym for antiProton ANnihilation at DArmstadt) detector. The physics aim, in a broader sense, is to address the fundamental problems of hadron physics and aspects of Quantum Chromo Dynamics (QCD) at low energies. The proposed work in India will consist of several parts: (i) development of a SiPM based scintillation tile hodoscope for TOF information, (ii) development of a luminosity detector (silicon strip detector), and (iii) simulation studies of these detectors design as well as physics case studies. The present paper reports the initial simulation studies that have been started at Nuclear Physics Division (NPD), BARC, on the silicon photomultiplier(SiPM) based fast scintillation detector (SciTil). The hardware development activities on this SciTil detector, that are also going on in parallel at NPD, has been reported in an another contribution to this proceedings

  14. Imaging with SiPMs in noble-gas detectors

    Science.gov (United States)

    Yahlali, N.; Fernandes, L. M. P.; González, K.; Garcia, A. N. C.; Soriano, A.

    2013-01-01

    Silicon photomultipliers (SiPMs) are photosensors widely used for imaging in a variety of high energy and nuclear physics experiments. In noble-gas detectors for double-beta decay and dark matter experiments, SiPMs are attractive photosensors for imaging. However they are insensitive to the VUV scintillation emitted by the noble gases (xenon and argon). This difficulty is overcome in the NEXT experiment by coating the SiPMs with tetraphenyl butadiene (TPB) to convert the VUV light into visible light. TPB requires stringent storage and operational conditions to prevent its degradation by environmental agents. The development of UV sensitive SiPMs is thus of utmost interest for experiments using electroluminescence of noble-gas detectors. It is in particular an important issue for a robust and background free ββ0ν experiment with xenon gas aimed by NEXT. The photon detection efficiency (PDE) of UV-enhanced SiPMs provided by Hamamatsu was determined for light in the range 250-500 nm. The PDE of standard SiPMs of the same model (S10362-33-50C), coated and non-coated with TPB, was also determined for comparison. In the UV range 250-350 nm, the PDE of the standard SiPM is shown to decrease strongly, down to about 3%. The UV-enhanced SiPM without window is shown to have the maximum PDE of 44% at 325 nm and 30% at 250 nm. The PDE of the UV-enhanced SiPM with silicon resin window has a similar trend in the UV range, although it is about 30% lower. The TPB-coated SiPM has shown to have about 6 times higher PDE than the non-coated SiPM in the range 250-315 nm. This is however below the performance of the UV-enhanced prototypes in the same wavelength range. Imaging in noble-gas detectors using UV-enhanced SiPMs is discussed.

  15. Imaging with SiPMs in noble-gas detectors

    International Nuclear Information System (INIS)

    Silicon photomultipliers (SiPMs) are photosensors widely used for imaging in a variety of high energy and nuclear physics experiments. In noble-gas detectors for double-beta decay and dark matter experiments, SiPMs are attractive photosensors for imaging. However they are insensitive to the VUV scintillation emitted by the noble gases (xenon and argon). This difficulty is overcome in the NEXT experiment by coating the SiPMs with tetraphenyl butadiene (TPB) to convert the VUV light into visible light. TPB requires stringent storage and operational conditions to prevent its degradation by environmental agents. The development of UV sensitive SiPMs is thus of utmost interest for experiments using electroluminescence of noble-gas detectors. It is in particular an important issue for a robust and background free ββ0ν experiment with xenon gas aimed by NEXT. The photon detection efficiency (PDE) of UV-enhanced SiPMs provided by Hamamatsu was determined for light in the range 250–500 nm. The PDE of standard SiPMs of the same model (S10362-33-50C), coated and non-coated with TPB, was also determined for comparison. In the UV range 250–350 nm, the PDE of the standard SiPM is shown to decrease strongly, down to about 3%. The UV-enhanced SiPM without window is shown to have the maximum PDE of 44% at 325 nm and 30% at 250 nm. The PDE of the UV-enhanced SiPM with silicon resin window has a similar trend in the UV range, although it is about 30% lower. The TPB-coated SiPM has shown to have about 6 times higher PDE than the non-coated SiPM in the range 250–315 nm. This is however below the performance of the UV-enhanced prototypes in the same wavelength range. Imaging in noble-gas detectors using UV-enhanced SiPMs is discussed.

  16. Study of point defect detectors in Si

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The importance of point defects in semiconductor and functionmaterials has been studied indetail, but effective means for detecting point defects has not been available for a long time.Theend of range defects in Si, produced by 140 keV Ge+ implantation,were investigated as detectorsfor measuring the interstitial concentration created by 42 keV B+ implantation.The concentrationof interstitial resulting from the B+ implantation and the behaviorof the interstitial flux underdifferent annealing condition were given. The enhanced diffusion in the borondoped EPI marker,resulting from mobile non-equilibrium interstitials wasdemonstrated to be transient. Interstitialfluxes arising from processing can be detected bytransient enhanced diffusion (TED) of dopedmarker layers as well.

  17. Performance Improved by Incorporating of Ru Atoms into Zr-Si Diffusion Barrier for Cu Metallization

    International Nuclear Information System (INIS)

    Thin Ru21Zr64Si15 films deposited on Si substrates by radio frequency reactive magnetron sputtering are studied and evaluated as diffusion barriers for Cu metallization. Cu/Ru21Zr64Si15/Si and Cu/Zr67Si33/Si structure samples are prepared under the same procedures for comparison. The thermal stability, phase formation, surface morphology and atomic depth profile of the Cu/Ru21Zr64Si15/Si and Cu/Zr67Si33/Si structures before and after annealing at different temperatures are investigated. In conjunction with these analyses, the Cu/Ru21Zr64Si15/Si contact system shows high thermal stability at least up to 650°C. The results obtained reveal that the incorporation of Ru atoms into the Zr67Si33 barrier layer is shown to be beneficial for improving the thermal stability of the Cu/barrier/Si contact system

  18. Position sensitive SiPM detector for Cherenkov applications

    CERN Document Server

    Gruber, L; Brunner, S E; Bühler, P; Marton, J; Suzuki, K

    2011-01-01

    A prototype of a position sensitive photo-detector with 5.6 x 5.6 cm2 detection area readout with 64 Hamamatsu MPPCs (S10931-100P) with 3 x 3 mm2 active area each has been built and tested. The photo-sensors are arranged in a 8 x 8 array with a quadratic mirror light guide on top. The module is currently readout by in-house developed preamplifier boards but employing existing ASIC chips optimized for SiPM readout is also planned. Such a device is one of the candidates to be used for photon detection in the PANDA DIRC detectors.

  19. Imaging with SiPMs in noble-gas detectors

    CERN Document Server

    Yahlali, N; González, K; Garcia, A N C; Soriano, A

    2012-01-01

    Silicon photomultipliers (SiPMs) are photosensors widely used for imaging in a variety of high energy and nuclear physics experiments. In noble-gas detectors for double-beta decay and dark matter experiments, SiPMs are attractive photosensors for imaging but they are insensitive to the VUV scintillation emitted by the noble gases (xenon and argon). This difficulty is overcome in the NEXT experiment by coating the SiPMs with tetraphenyl butadiene (TPB) to convert the VUV light into visible light. TPB requires stringent storage and operational conditions to prevent its degradation by environmental agents. The development of UV sensitive SiPMs is thus of utmost interest for experiments using UV light and for noble-gas detectors. It is in particular an important issue for a robust and background free neutrinoless double-beta decay experiment with xenon gas aimed by NEXT. The photon detection efficiency (PDE) of UV-enhanced SiPMs without protective window and with silicon resin window provided by Hamamatsu was det...

  20. Temperature- Dependent Barrier Characteristics of Inhomogeneous In/p-Si (100) Schottky Barrier Diodes

    Institute of Scientific and Technical Information of China (English)

    N.Tugluoglu; S.Karadeniz; S.Acar; M.Kasap2

    2004-01-01

    The current-voltage (I- V) characteristics of In/p-Si Schottky barrier diodes have been determined in the temperature range 100-300 K and have been interpreted based on the assumption of a Gaussian distribution of barrier heights due to barrier height inhomogeneities that prevail at the metal-semiconductor interface. The evaluation of the experimental I-V data reveals a decrease of zero-bias barrier height but an increase of ideality factor n with decreasing temperature. The inhomogeneities are considered to have Gaussian distribution with a mean zero-bias barrier height of 0.630 e V and standard deviation of 0.083 V at zero bias. Furthermore, the mean barrier height and the Richardson constant values were obtained to be 0.617eV and 20.71 A K-2 cm-2, respectively, by means of the modified Richardson plot, ln( I0/T2) - (q2σs20/2k2T2) versus 1000/T.

  1. Oscillations above the barrier in the fusion of 28Si + 28Si

    Directory of Open Access Journals (Sweden)

    G. Montagnoli

    2015-06-01

    Full Text Available Fusion cross sections of 28Si + 28Si have been measured in a range above the barrier with a very small energy step (ΔElab=0.5 MeV. Regular oscillations have been observed, best evidenced in the first derivative of the energy-weighted excitation function. For the first time, quite different behaviors (the appearance of oscillations and the trend of sub-barrier cross sections have been reproduced within the same theoretical frame, i.e., the coupled-channel model using the shallow M3Y + repulsion potential. The calculations suggest that channel couplings play an important role in the appearance of the oscillations, and that the simple relation between a peak in the derivative of the energy-weighted cross section and the height of a centrifugal barrier is lost, and so is the interpretation of the second derivative of the excitation function as a barrier distribution for this system, at energies above the Coulomb barrier.

  2. Oscillations above the barrier in the fusion of 28Si + 28Si

    CERN Document Server

    Montagnoli, G; Esbensen, H; Corradi, L; Courtin, S; Fioretto, E; Grebosz, J; Haas, F; Jia, H M; Jiang, C L; Mazzocco, M; Michelagnoli, C; Mijatovic, T; Montanari, D; Parascandolo, C; Scarlassara, F; Strano, E; Szilner, S; Torresi, D

    2015-01-01

    Fusion cross sections of 28Si + 28Si have been measured in a range above the barrier with a very small energy step (DeltaElab = 0.5 MeV). Regular oscillations have been observed, best evidenced in the first derivative of the energy-weighted excitation function. For the first time, quite di?erent behaviors (the appearance of oscillations and the trend of sub-barrier cross sections) have been reproduced within the same theoretical frame, i.e., the coupled-channel model using the shallow M3Y+repulsion potential. The calculations suggest that channel couplings play an important role in the appearance of the oscillations, and that the simple relation between a peak in the derivative of the energy-weighted cross section and the height of a centrifugal barrier is lost, and so is the interpretation of the second derivative of the excitation function as a barrier distribution for this system, at energies above the Coulomb barrier.

  3. Reducing the effective barrier height of a PtSi Schottky diode by a p{sup +} doping spike using pulsed laser doping

    Energy Technology Data Exchange (ETDEWEB)

    Li, M C [Department of Materials Physics and Chemistry, School of Materials Science and Engineering, Harbin Institute of Technology, PO Box 428, Harbin 150001 (China); Zhao, L C [Department of Materials Physics and Chemistry, School of Materials Science and Engineering, Harbin Institute of Technology, PO Box 428, Harbin 150001 (China); Chen, X K [Laboratory of Laser Molecular Beam Epitaxy, Lanzhou Institute of Physics, Lanzhou (China)

    2003-10-07

    The structure of PtSi/p{sup +}/p-Si fabricated by chemical vapour doping has been investigated for reduction of the Schottky barrier height. The interface structure and photoelectric properties of PtSi/p{sup +}/p-Si thin film structure have been studied. The results from AES profile analysis show that doped boron moves with the PtSi/Si interface during silicide growth. Concomitantly, the boron at the PtSi/Si interface out-diffuses to the Pt-PtSi interface. Finally, the boron piles up at the surface. It has been considered that the redistribution of the dopant boron is due to the solubility of the dopant in the silicide. The Schottky barrier height of PtSi/p{sup +}/p-Si is 0.13 eV (for cutoff wavelength 9.5 {mu}m). That is lower than the 0.19 eV value of PtSi/p-Si (for cutoff wavelength 6.5 {mu}m). Since the Schottky barrier height is lowered, the cutoff wavelength can be extended. Due to the Fowler dependence, the detector's quantum efficiency can be improved.

  4. Response function of semiconductor detectors, Ge and Si(Li); Funcao resposta de detectores semicondutores, Ge e Si(Li)

    Energy Technology Data Exchange (ETDEWEB)

    Zevallos Chavez, Juan Yury

    2003-07-01

    The Response Function (RF) for Ge and Si(Li) semiconductor detectors was obtained. The RF was calculated for five detectors, four Hp Ge with active volumes of 89 cm{sup 3} , 50 cm{sup 3} , 8 cm{sup 3} and 5 cm{sup 3}, and one Si(Li) with 0.143 cm{sup 3} of active volume. The interval of energy studied ranged from 6 keV up to 1.5 MeV. Two kinds of studies were done in this work. The first one was the RF dependence with the detection geometry. Here the calculation of the RF for a geometry named as simple and an extrapolation of that RF, were both done. The extrapolation process analyzed both, spectra obtained with a shielding geometry and spectra where the source-detector distance was modified. The second one was the RF dependence with the detection electronics. This study was done varying the shaping time of the pulse in the detection electronics. The purpose was to verify the effect of the ballistic deficit in the resolution of the detector. This effect was not observed. The RF components that describe the region of the total absorption of the energy of the incident photons, and the partial absorption of this energy, were both treated. In particular, empirical functions were proposed for the treatment of both, the multiple scattering originated in the detector (crystal), and the photon scattering originated in materials of the neighborhood of the crystal. Another study involving Monte Carlo simulations was also done in order to comprehend the photon scattering structures produced in an iron shield. A deconvolution method is suggested, for spectra related to scattered radiation in order to assess the dose delivered to the scatterer. (author)

  5. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    Science.gov (United States)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  6. Drift power supply for Si(Li) detector

    International Nuclear Information System (INIS)

    A drift power supply for Si(Li) detector has been developed, which is completely different from many other power supplies for common use. The drift power supply provides the most extensive useful voltage range of 0∼1000 V, and is continuously adjustable. It has good stability, constant power and compact structure, and the maximum output current is 100 mA. Since SCR's (silicon-controlled-rectifier) with trigger diodes and other new components are adopted and a power restriction circuit is considered in design, so during the operation when the resistance rate of silicon pieces in drifting process changes with the temperature, the power remains constant. The lower the resistance rate when the temperature raises, the higher the drift current and lower the voltage on the silicon piece. On the contrast, the higher the resistance rate when the temperature lowers, the lower the drift current, and higher the voltage on the silicon piece. Forty pieces of Si(Li) detector have been successfully drifted by using this drift power supply

  7. Phase Stability and Thermal Conductivity of Composite Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Benkel, Samantha; Zhu, Dongming

    2011-01-01

    Advanced environmental barrier coatings are being developed to protect SiC/SiC ceramic matrix composites in harsh combustion environments. The current coating development emphasis has been placed on the significantly improved cyclic durability and combustion environment stability in high-heat-flux and high velocity gas turbine engine environments. Environmental barrier coating systems based on hafnia (HfO2) and ytterbium silicate, HfO2-Si nano-composite bond coat systems have been processed and their stability and thermal conductivity behavior have been evaluated in simulated turbine environments. The incorporation of Silicon Carbide Nanotubes (SiCNT) into high stability (HfO2) and/or HfO2-silicon composite bond coats, along with ZrO2, HfO2 and rare earth silicate composite top coat systems, showed promise as excellent environmental barriers to protect the SiC/SiC ceramic matrix composites.

  8. Creep Behavior of Hafnia and Ytterbium Silicate Environmental Barrier Coating Systems on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming; Fox, Dennis S.; Ghosn, Louis J.; Harder, Bryan

    2011-01-01

    Environmental barrier coatings will play a crucial role in future advanced gas turbine engines because of their ability to significantly extend the temperature capability and stability of SiC/SiC ceramic matrix composite (CMC) engine components, thus improving the engine performance. In order to develop high performance, robust coating systems for engine components, appropriate test approaches simulating operating temperature gradient and stress environments for evaluating the critical coating properties must be established. In this paper, thermal gradient mechanical testing approaches for evaluating creep and fatigue behavior of environmental barrier coated SiC/SiC CMC systems will be described. The creep and fatigue behavior of Hafnia and ytterbium silicate environmental barrier coatings on SiC/SiC CMC systems will be reported in simulated environmental exposure conditions. The coating failure mechanisms will also be discussed under the heat flux and stress conditions.

  9. Optimization of Silicon parameters as a betavoltaic battery: Comparison of Si p-n and Ni/Si Schottky barrier

    Science.gov (United States)

    Rahmani, Faezeh; Khosravinia, Hossein

    2016-08-01

    Theoretical studies on the optimization of Silicon (Si) parameters as the base of betavoltaic battery have been presented using Monte Carlo simulations and the state equations in semiconductor to obtain maximum power. Si with active area of 1 cm2 has been considered in p-n junction and Schottky barrier structure to collect the radiation induced-charge from 10 mCi cm-2 of Nickle-63 (63Ni) Source. The results show that the betavoltaic conversion efficiency in the Si p-n structure is about 2.7 times higher than that in the Ni/Si Schottky barrier structure.

  10. Effect of a metal electrode on the radiation tolerance of a SiC neutron detector

    Science.gov (United States)

    Park, Junesic; Shin, Hee-Sung; Kim, Ho-Dong; Kim, Han Soo; Park, Se Hwan; Lee, Cheol Ho; Kim, Yong Kyun

    2012-08-01

    The Korea Atomic Energy Research Institute (KAERI) has developed a silicon carbide (SiC) diode as a neutron detector that can be used in harsh environments such as nuclear reactor cores and spent fuel. The radiation tolerance of the SiC detector was studied in the present work. Especially, the effect of a metal electrode on the radiation tolerance of the SiC detector was studied. Four different types of SiC detectors were fabricated, and the operation properties of the detectors were measured and compared before and after neutron irradiations of 2.16 × 1015 n/cm2 and 5.40 × 1017 n/cm2. From the comparison, the detector with a Ti/Au electrode structure showed the highest radiation tolerance among detectors. A detector assembly was fabricated using two types of SiC p-i-n diode detectors: one containing 6LiF and the other without it. Signals from the detectors were measured in the current mode to minimize the noise of the detector. Signal currents from detectors were measured for neutron fluxes ranging from 5.54 × 106 n/cm2 s to 2.86 × 108 n/cm2 s and gamma doses up to 100 Gy/h.

  11. Research Update: Reactively sputtered nanometer-thin ZrN film as a diffusion barrier between Al and boron layers for radiation detector applications

    Energy Technology Data Exchange (ETDEWEB)

    Golshani, Negin, E-mail: negingolshani@gmail.com; Mohammadi, V.; Schellevis, H.; Beenakker, C. I. M.; Ishihara, R. [ECTM, DIMES, Faculty of Electrical Engineering (EWI), Delft University of Technology (TU Delft), Feldmannweg 17, P.O. Box 5053, 2628 CT Delft (Netherlands)

    2014-10-01

    In this paper, optimization of the process flow for PureB detectors is investigated. Diffusion barrier layers between a boron layer and the aluminum interconnect can be used to enhance the performance and visual appearance of radiation detectors. Few nanometers-thin Zirconium Nitride (ZrN) layer deposited by reactive sputtering in a mixture of Ar/N{sub 2}, is identified as a reliable diffusion barrier with better fabrication process compatibility than others. The barrier properties of this layer have been tested for different boron layers deposited at low and high temperatures with extensive optical microscopy analyses, electron beam induced current, SEM, and electrical measurements. This study demonstrated that spiking behavior of pure Al on Si can be prevented by the thin ZrN layer thus improving the performance of the radiation detectors fabricated using boron layer.

  12. Charge collection efficiency mapping of interdigitated 4H-SiC detectors

    CERN Document Server

    Vittone, E; Pastuovic, Z; Olivero, P; Jaksic, M

    2016-01-01

    The Ion Beam Induced Charge Collection (IBIC) technique was used to map the charge collection efficiency (CCE) of a 4H-SiC photodetector with coplanar interdigitated Schottky barrier electrodes and a common ohmic contact on the back side. IBIC maps were obtained using focused proton beams with energies of 0.9 MeV and 1.5 MeV, at different bias voltages and different sensitive electrode configurations (charge collection at the top Schottky or at the back Ohmic contact). These different experimental conditions have been modeled using a two dimensional finite element code to solve the adjoint carrier continuity equations and the results obtained have been compared with experimental results. The excellent consistency between the simulated and experimental CCE maps allows an exhaustive interpretation of the charge collection mechanisms occurring in pixellated or strip detectors.

  13. First large scale application of novel Si stripixel detector in real large experiment: Si VTX in PHENIX upgrade at RHIC

    Institute of Scientific and Technical Information of China (English)

    LI Zheng; H. ENYO; Y. GOTO; J. TOJO; Y. AKIBA; R. NOUICER; A. L. DESHPANDE; K. BOYLE; V. CIANCIOLO

    2006-01-01

    2D position sensitive,single-sided Si stripixel detector was selected as the one of the two main components of the Si vertex tracker (Si SVX) in the upgraded PHENIX detector at RHIC (relativistic heavy ion collider) in Brookhaven National Laboratory (BNL). This is the first large scale application of the novel Si stripixel detector in a real large experiment after many years of research and development at BNL. The first and second prototype fabrication runs of the SVX stripixel detectors were carried out successfully in BNL's Si detector development and processing Lab. The processing of these stripixel detectors is similar to that for the standard single-sided strip detectors: one-sided processing,single implant for the pixel (strip) electrodes,etc. The only additional processing step is the double metal process,a technology that is simple and well matured by many Si detector processing industries and labs,including BNL. The laser and beam tests on those prototype detectors show the 2D position sensitivity and good position resolution in both X and U coordinates (about 25 μm for 80 μm pitch). For the mass production of 400 sensors needed for the Si SVX,the processing technology has been successfully transferred to the industrial: Hamamatsu Photonics (HPK). HPK has produced a pre-production run of stripixel sensors with the full PHENIX SVX specification on 150 mm diameter wafers. The laser tests on these pre-production wafers show good signal to noise ratio (about 20:1).

  14. Fast SiPM Readout of the PANDA TOF Detector

    Science.gov (United States)

    Böhm, M.; Lehmann, A.; Motz, S.; Uhlig, F.

    2016-05-01

    For the identification of low momentum charged particles and for event timing purposes a barrel Time-of-Flight (TOF) detector surrounding the interaction point is planned for the PANDA experiment at FAIR . Since the boundary conditions in terms of available radial space and radiation length are quite strict the favored layout is a hodoscope composed of several thousand small scintillating tiles (SciTils) read out by silicon photomultipliers (SiPMs). A time resolution of well below 100 ps is aimed for. With the originally proposed 30 × 30 × 5 mm3 SciTils read out by two single 3 × 3 mm2 SiPMs at the rims of the scintillator the targeted time resolution can be just reached, but with a considerable position dependence across the scintillator surface. In this paper we discuss other design options to further improve the time resolution and its homogeneity. It will be shown that wide scintillating rods (SciRods) with a size of, e.g., 50 × 30 × 5 mm3 or longer and read out at opposite sides by a chain of four serially connected SiPMs a time resolution down to 50 ps can be reached without problems. In addition, the position dependence of the time resolution is negligible. These SciRods were tested in the laboratory with electrons of a 90Sr source and under real experimental conditions in a particle beam at CERN. The measured time resolutions using fast BC418 or BC420 plastic scintillators wrapped in aluminum foil were consistently between 45 and 75 ps dependent on the SciRod design. This is a significant improvement compared to the original SciTil layout.

  15. Si, CdTe and CdZnTe radiation detectors for imaging applications

    OpenAIRE

    Schulman, Tom

    2006-01-01

    The structure and operation of CdTe, CdZnTe and Si pixel detectors based on crystalline semiconductors, bump bonding and CMOS technology and developed mainly at Oy Simage Ltd. And Oy Ajat Ltd., Finland for X- and gamma ray imaging are presented. This detector technology evolved from the development of Si strip detectors at the Finnish Research Institute for High Energy Physics (SEFT) which later merged with other physics research units to form the Helsinki Institute of Physics (HIP). General ...

  16. Nitrogen doping effect upon hole tunneling characteristics of Si barriers in Si{sub 1-x}Ge{sub x}/Si resonant tunneling diode

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Tomoyuki [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Sakuraba, Masao, E-mail: sakuraba.masao@myad.jp [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Murota, Junichi [Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2014-04-30

    Nitrogen atomic-layer (N AL) doping effects upon hole tunneling characteristics of double 4 nm-thick Si barriers in the strained Si{sub 1−x}Ge{sub x}/Si(100) hole resonant tunneling diode (RTD) were investigated. At a Si cap layer on Si{sub 1−x}Ge{sub x}(100) (x = 0.2 and 0.4) formed at 500 °C, it was found that NH{sub 3} reaction was drastically enhanced at 500 °C especially at the Si cap layer thickness less than 0.5 nm, and the fact indicates a possibility of significant intermixing at the Si/Si{sub 1−x}Ge{sub x} heterointerface. From current–voltage characteristics of the RTDs, drastic current suppression by N AL doping in the Si barriers can be observed with typical degree of current suppression as high as 10{sup 3}–10{sup 5} at − 10 mV. Moreover, it was found that N AL doping influences, not only upon such current suppression, but slightly upon negative differential conductance characteristics. - Highlights: • NH{sub 3} reaction enhancement on a thin Si cap layer on Si{sub 1−x}Ge{sub x}(100). • Drastic current suppression by N atomic-layer doping in Si barriers. • N atomic-layer doping effect upon negative differential conductance characteristics.

  17. POSSuMUS: a position sensitive scintillating muon SiPM detector

    CERN Document Server

    Ruschke, Alexander

    The development of a modular designed large scale scintillation detector with a two-dimensional position sensitivity is presented in this thesis. This novel POsition Sensitive Scintillating MUon SiPM Detector is named POSSuMUS. The POSSuMUS detector is capable to determine the particle’s position in two space dimensions with a fast trigger capability. Each module is constructed from two trapezoidal shaped plastic scintillators to form one rectangular shaped detector module. Both trapezoids are optically insulated against each other. In both trapezoids the scintillation light is collected by plastic fibers and guided towards silicon photomultipliers (SiPMs). SiPMs are light sensors which are capable to detect even smallest amounts of light. By combining several detector modules, position sensitive areas from 100 cm2 to few m2 are achievable with few readout channels. Therefore, POSSuMUS provides a cost effective detector concept. The position sensitivity along the trapezoidal geometry of one detector module ...

  18. Calculation of the Electronic Parameters of an Al/DNA/p-Si Schottky Barrier Diode Influenced by Alpha Radiation

    Directory of Open Access Journals (Sweden)

    Hassan Maktuff Jaber Al-Ta'ii

    2015-02-01

    Full Text Available Many types of materials such as inorganic semiconductors have been employed as detectors for nuclear radiation, the importance of which has increased significantly due to recent nuclear catastrophes. Despite the many advantages of this type of materials, the ability to measure direct cellular or biological responses to radiation might improve detector sensitivity. In this context, semiconducting organic materials such as deoxyribonucleic acid or DNA have been studied in recent years. This was established by studying the varying electronic properties of DNA-metal or semiconductor junctions when exposed to radiation. In this work, we investigated the electronics of aluminium (Al/DNA/silicon (Si rectifying junctions using their current-voltage (I-V characteristics when exposed to alpha radiation. Diode parameters such as ideality factor, barrier height and series resistance were determined for different irradiation times. The observed results show significant changes with exposure time or total dosage received. An increased deviation from ideal diode conditions (7.2 to 18.0 was observed when they were bombarded with alpha particles for up to 40 min. Using the conventional technique, barrier height values were observed to generally increase after 2, 6, 10, 20 and 30 min of radiation. The same trend was seen in the values of the series resistance (0.5889–1.423 Ω for 2–8 min. These changes in the electronic properties of the DNA/Si junctions could therefore be utilized in the construction of sensitive alpha particle detectors.

  19. Environmental Barrier Coating Development for SiC/SiC Ceramic Matrix Composites: Recent Advances and Future Directions

    Science.gov (United States)

    Zhu, Dongming

    2016-01-01

    This presentation briefly reviews the SiC/SiC major environmental and environment-fatigue degradations encountered in simulated turbine combustion environments, and thus NASA environmental barrier coating system evolution for protecting the SiC/SiC Ceramic Matrix Composites for meeting the engine performance requirements. The presentation will review several generations of NASA EBC materials systems, EBC-CMC component system technologies for SiC/SiC ceramic matrix composite combustors and turbine airfoils, highlighting the temperature capability and durability improvements in simulated engine high heat flux, high pressure, high velocity, and with mechanical creep and fatigue loading conditions. This paper will also focus on the performance requirements and design considerations of environmental barrier coatings for next generation turbine engine applications. The current development emphasis is placed on advanced NASA candidate environmental barrier coating systems for SiC/SiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. The efforts have been also directed to developing prime-reliant, self-healing 2700F EBC bond coat; and high stability, lower thermal conductivity, and durable EBC top coats. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, erosion-impact resistance, and long-term fatigue-environment system durability performance will be described. The research and development opportunities for turbine engine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be briefly discussed.

  20. Barrier height and ideality factor dependency on identically produced small Au/p-Si Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Yeganeh, M. A. [Faculty of Physics, Baku State University, Academic Zahid Xalilov-23, AZ 1148, Baku (Azerbaijan); Rahmatollahpur, S. H., E-mail: rahmatsh@bnrc.i [Departments of Physics, Sharif University of Technology, 11365-9567, Tehran (Iran, Islamic Republic of)

    2010-07-15

    Small high-quality Au/P-Si Schottky barrier diodes (SBDs) with an extremely low reverse leakage current using wet lithography were produced. Their effective barrier heights (BHs) and ideality factors from current-voltage (I-V) characteristics were measured by a conducting probe atomic force microscope (C-AFM). In spite of the identical preparation of the diodes there was a diode-to-diode variation in ideality factor and barrier height parameters. By extrapolating the plots the built in potential of the Au/p-Si contact was obtained as V{sub bi} = 0.5425 V and the barrier height value {Phi}{sub B(C-V)} was calculated to be {Phi}{sub B(C-V)} = 0.7145 V for Au/p-Si. It is found that for the diodes with diameters smaller than 100 {mu}m, the diode barrier height and ideality factor dependency to their diameters and correlation between the diode barrier height and its ideality factor are nonlinear, where similar to the earlier reported different metal semiconductor diodes in the literature, these parameters for the here manufactured diodes with diameters more than 100 {mu}m are also linear. Based on the very obvious sub-nanometer C-AFM produced pictures the scientific evidence behind this controversy is also explained.

  1. Deposition of SiOx barrier films by O2/TMDSO RF-PECVD

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Li; Fu Ya-Bo; Chen Qiang; Ge Yuan-Jing

    2007-01-01

    This paper reports that the SiOx barrier films are deposited on polyethylene terephthalate substrate by plasmaenhanced chemical vapour deposition (PECVD) for the application of transparent barrier packaging. The variations of O2/Tetramethyldisiloxane (TMDSO) ratio and input power in radio frequency (RF) plasma are carried out to optimize barrier properties of the SiOx coated film. The properties of the coatings are characterized by Fourier transform infrared,water wpour transmission rate (WVTR), oxygen transmission rate (OTR), and atomic force microscopy analysers. It is found that the O2/TMDSO ratio exceeding 2:1 and the input power over 200 W yield SiOx films with low carbon contents which can be good to the barrier (WVTR and OTR) properties of the SiOx coatings. Also, the film properties not only depend on oxygen concentration of the inlet gas mixtures and input power, but also relate to the surface morphology of the coating.

  2. Fabrication and characteristics of lateral Ti/4H-SiC Schottky barrier diodes

    Institute of Scientific and Technical Information of China (English)

    王守国; 杨林安; 张义门; 张玉明; 张志勇; 闫军锋

    2003-01-01

    This paper describes the fabrication and characteristics of the lateral Ti/4H-SiC Schottky barrier diodes (SBDs).SBDs are fabricated by nitrogen ion implantation into p-type 4H-SiC epitaxial layer. The implant depth profile is simulated using the Monte Carlo simulator TRIM. Measurements of the reverse I-V characteristics demonstrate a low reverse current, that is good enough for many SiC-based devices such as SiC metal-semiconductor field-effect transistors,and SiC static induction transistors. The parameters of the diodes are extracted from the forward I-V characteristics.The barrier height b of Ti/4H-SiC is 0.95 eV.

  3. Uncooled Radiation Hard SiC Schottky VUV Detectors Capable of Single Photon Sensing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, fabricate, characterize and commercialize very large area, uncooled and radiative hard 4H-SiC VUV detectors capable of near single...

  4. FIR Detectors/Cameras Based on GaN and Si Field-Effect Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SETI proposes to develop GaN and Si based multicolor FIR/THz cameras with detector elements and readout, signal processing electronics integrated on a single chip....

  5. Analysis and comparison of the breakdown performance of semi- insulator and dielectric passivated Si strip detectors

    CERN Document Server

    Ranjan, Kirti; Chatterji, S; Srivastava-Ajay, K; Shivpuri, R K

    2002-01-01

    The harsh radiation environment in future high-energy physics (HEP) experiments like LHC provides a challenging task to the performance of Si microstrip detectors. Normal operating condition for silicon detectors in HEP experiments are in most cases not as favourable as for experiments in nuclear physics. In HEP experiments the detector may be exposed to moisture and other adverse atmospheric environment. It is therefore utmost important to protect the sensitive surfaces against such poisonous effects. These instabilities can be nearly eliminated and the performance of Si detectors can be improved by implementing suitably passivated metal-overhang structures. This paper presents the influence of the relative permittivity of the passivant on the breakdown performance of the Si detectors using computer simulations. The semi-insulator and the dielectric passivated metal-overhang structures are compared under optimal conditions. The influence of various parameters such as passivation layer thickness, junction dep...

  6. Novel Gas Barrier SiOC Coating to PET Bottles through a Hot Wire CVD Method

    OpenAIRE

    Nakaya, Masaki; Kodama, Kenji; Yasuhara, Shigeo; Hotta, Atsushi

    2016-01-01

    In an attempt to enhance the gas barrier enhancement of plastic containers such as poly(ethylene terephthalate) bottles, a novel method was found using a hot wire CVD technique, where tantalum wire is heated and exposed to a gas flow of vinyl silane. The resultant SiOC thin film was confirmed to characteristically contain Si-Si bonds in its surface and demonstrate a remarkably and highly practical decrease of the permeation of various gas through poly(ethylene terephthalate) bottles.

  7. Effect of Annealing Ambience on the Chemical Stability of Zr-Si-N Diffusion Barrier

    Institute of Scientific and Technical Information of China (English)

    SONGZhong-xiao; WANGYuan; XUKe-wei; LIUChun-liang

    2004-01-01

    Zr-Si-N films were deposited by RF magnetron sputtering (MS) technique. A Cu film on the top of Zr-Si-N films was prepared by DC pulsed magnetron sputtering. The Cu/Zr-Si-N systems were annealed in vacuum and N2/H2 gasmixture at 800℃, respectively. The structure of the films were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and four-point probe method. The sheet resistances of the Cu/Zr-Si-N/Si contact systems annealed in N2/H2 gas mixture were lower than those of the specimens annealed in vacuum at 800℃. The residual oxygen contamination from vacuum annealing ambience influences the sheet resistances of the Cu/Zr-Si-N/Si contact systems due to residual oxygen contamination and/or voids in Cu films. Though thermal stabilities of the Cu/Zr-Si-N/Si systems were maintained up to 800℃ when annealed in vacuum and N2/H2 gas mixture, the changes of thermal stability of specimens were noticeable. The vacuum can accelerate the oxidation and decomposition of Zr-Si-N barrier. On the contrary, N2/H2 gas mixture prevent from the Zr-Si-N barrier oxidation and decomposition.

  8. Effect of Annealing Ambience on the Chemical Stability of Zr-Si-N Diffusion Barrier

    Institute of Scientific and Technical Information of China (English)

    SONG Zhong-xiao; WANG Yuan; XU Ke-wei; LIU Chun-liang

    2004-01-01

    Zr-Si-N films were deposited by RF magnetron sputtering (MS) technique. A Cu film on the top of Zr-Si-N films was prepared by DC pulsed magnetron sputtering. The Cu/Zr-Si-N systems were annealed in vacuum and N2/H2 gas mixture at 800℃, respectively. The structure of the films were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and four-point probe method. The sheet resistances of the Cu/Zr-Si-N/Si contact systems annealed in N2/H2 gas mixture were lower than those of the specimens annealed in vacuum at 800℃. The residual oxygen contamination from vacuum annealing ambience influences the sheet resistances of the Cu/Zr-Si-N/Si contact systems due to residual oxygen contamination and/or voids in Cu films. Though thermal stabilities of the Cu/Zr-Si-N/Si systems were maintained up to 800℃ when annealed in vacuum and N2/H2 gas mixture, the changes of thermal stability of specimens were noticeable. The vacuum can accelerate the oxidation and decomposition of Zr-Si-N barrier. On the contrary, N2/H2 gas mixture prevent from the Zr-Si-N barrier oxidation and decomposition.

  9. POSSuMUS. A position sensitive scintillating muon SiPM detector

    International Nuclear Information System (INIS)

    The development of a modular designed large scale scintillation detector with a two-dimensional position sensitivity is presented in this thesis. This novel POsition Sensitive Scintillating MUon SiPM Detector is named POSSuMUS. The POSSuMUS detector is capable to determine the particle's position in two space dimensions with a fast trigger capability. Each module is constructed from two trapezoidal shaped plastic scintillators to form one rectangular shaped detector module. Both trapezoids are optically insulated against each other. In both trapezoids the scintillation light is collected by plastic fibers and guided towards silicon photomultipliers (SiPMs). SiPMs are light sensors which are capable to detect even smallest amounts of light. By combining several detector modules, position sensitive areas from 100 cm2 to few m2 are achievable with few readout channels. Therefore, POSSuMUS provides a cost effective detector concept. The position sensitivity along the trapezoidal geometry of one detector module is achieved by the path length dependent amount of detected light for crossing particles. The ratio of the light yields in both trapezoids is calculated. This value corresponds to the position of the particle traversing the detector. A spatial resolution in the order of several mm is foreseen. The position sensitivity along the scintillator module is determined by the propagation time of light to the SiPMs located on opposite sides of the detector. A spatial resolution of few cm is expected for this direction. The POSSuMUS detector is applicable as large area trigger detector with a two dimensional position information of crossing particles. This is suitable in detector tests of large area precesion detectors or for measuring the small angle scattering of cosmic muons. At the beginning of this thesis, the determination of important SiPM characteristics like the breakdown voltage is presented. In the course of this work the detector principle is proven by the

  10. Response of timepix detector with GaAs:Cr and Si sensor to heavy ions

    Science.gov (United States)

    Abu Al Azm, S. M.; Chelkov, G.; Kozhevnikov, D.; Guskov, A.; Lapkin, A.; Leyva Fabelo, A.; Smolyanskiy, P.; Zhemchugov, A.

    2016-05-01

    The response of the Timepix detector to neon ions with kinetic energy 77 and 158.4 MeV has been studied at the cyclotron U-400M of the JINR Flerov Laboratory of Nuclear Reaction. Sensors produced from gallium arsenide compensated by chromium and from silicon are used for these measurements. While in Timepix detector with Si sensor the well-known so-called "volcano effect" observed, in Timepix detector with GaAs:Cr sensor such effect was completely absent. In the work the behavior of the Timepix detector with GaAs:Cr sensor under irradiation with heavy ions is described in comparison with the detector based on Si sensor. Also the possible reason for absence of "volcano" effect in GaAs:Cr detector is proposed.

  11. Position sensitive detection of thermal neutrons with solid state detectors (Gd Si planar detectors)

    CERN Document Server

    Bruckner, G; Rauch, H; Weilhammer, P

    1999-01-01

    Recent advances in the technology of position sensitive silicon detectors and the corresponding electronics allow the construction of fast time response thermal neutron detectors. These detectors also exhibit excellent position resolution by combination of silicon detectors with thin Gd converter foils. We constructed several one- and two-dimensional prototype detectors, using DC and AC coupled silicon strip detectors, pad detectors and different VLSI readout electronics. The position resolution and the detector efficiency for different converters at wavelengths from 1.1 to 3.3 A were determined at the TRIGA reactor in Vienna and at the ILL in Grenoble. Spatial resolutions of less than 100 mu m and efficiencies up to 40% have been achieved. The results of these measurements are compared with a Monte Carlo simulation of the detector operation. These detectors can also be used for phase topography experiments using perfect crystal neutron interferometers. In certain cases an increase of the sensitivity in the o...

  12. Dependency of barrier height and ideality factor on identically produced small Au/p-Si Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Yeganeh, M.A. [Faculty of Physics, Baku State University, Academic Zahid Xelilov kuecesi-23, AZ 1148 (Azerbaijan); Material School, POB 55515-196, Binab (Iran, Islamic Republic of); Rahmatollahpur, Sh. [Departments of Physics, Sharif University of Technology, 11365-9567, Tehran (Iran, Islamic Republic of); Material School, POB 55515-196, Binab (Iran, Islamic Republic of); Sadighi-Bonabi, R., E-mail: sadighi@sharif.i [Departments of Physics, Sharif University of Technology, 11365-9567, Tehran (Iran, Islamic Republic of); Mamedov, R. [Faculty of Physics, Baku State University, Academic Zahid Xelilov kuecesi-23, AZ 1148 (Azerbaijan)

    2010-08-15

    Small high-quality Au/p-Si Schottky barrier diodes (SBDs) with extremely low reverse leakage current using wet lithography were produced. Their effective barrier heights (BHs) and ideality factors from current-voltage (I-V) characteristics were measured by a conducting probe atomic force microscope (C-AFM). In spite of identical preparation of the diodes there was a diode-to-diode variation in ideality factor and barrier height parameters. By extrapolating the plots the built-in potential of the Au/p-Si contact was obtained as V{sub bi}=0.5425 V and the barrier height value ({Phi}{sub B(C-V)}) was calculated to be {Phi}{sub B(C-V)}=0.7145 V for Au/p-Si for a typical 100 {mu}m diode diameters. In the present work the nonlinear dependency of BH and ideality factor on the diode diameter studied fundamentally and an experimental relation for this new behavior is derived. It is found that for the diodes with diameters smaller than 100 {mu}m the diode barrier height and ideality factor dependency to their diameters and correlation between the diode barrier height and its ideality factor are nonlinear, which is similar to the earlier reported different metal semiconductor diodes in the literature, these parameters for the here manufactured diodes with diameters more than 100 {mu}m are also linear. Based on the very obvious sub-nanometer C-AFM produced pictures, the scientific evidence behind this controversy is also explained.

  13. Evaluation of the barrier capability of Zr-Si films with different substrate temperature for Cu metallization

    International Nuclear Information System (INIS)

    Barrier capability of Zr-Si diffusion barriers in Cu metallization has been investigated. Amorphous Zr-Si diffusion barriers were deposited on the Si substrates by RF reactive magnetron sputtering under various substrate temperatures. An increase in substrate temperature results in a slightly decreased deposition rate together with an increase in mass density. An increase in substrate temperature also results in grain growth as deduced from field emission scanning electron microscopy (FE-SEM) micrographs. X-ray diffraction (XRD) spectra and Auger electron spectroscopy (AES) depth profiles for Cu/Zr-Si(RT)/Si and Cu/Zr-Si(300 deg. C)/Si samples subjected to anneal at various temperatures show that the thermal stability was strongly correlated with the deposition temperature (consequently different density and chemical composition etc.) of the Zr-Si barrier layers. ZrSi(300 deg. C) with higher mass density make the Cu/Zr-Si(300 deg. C)/Si sample more stable. The appearance of Cu3Si in the Cu/Zr-Si/Si sample is attributed to the failure mechanism which may be associated with the diffusion of Cu and Si via the grain boundaries of the Zr-Si barriers.

  14. Study of the characteristics of SiPMs matrix as a photosensor for the scintillation detectors

    CERN Document Server

    Dzaparova, I M; Gavrilyuk, Yu M; Petkov, V B; Sergeev, A V; Volchenko, V I; Yakimenko, S P; Yanin, A F

    2015-01-01

    The matrices formed of silicon photomultipliers (SiPMs) are very promising photosensors for the scintillation detectors. The use of SiPM matrices with appropriate optical collector gives, in principle, a possibility to do a snapshot of glowing track of charged particle traversing a scintillator. The prototype of such scintillation detector is under development now in INR RAS. The preliminary results of characterization study of the matrix ArrayC-60035-64P-PCB (SensL company) for the prototype of such detector are presented.

  15. Improvements in Realizing 4H-SiC Thermal Neutron Detectors

    Directory of Open Access Journals (Sweden)

    Issa F.

    2016-01-01

    Full Text Available In this work we presented two types of 4H-SiC semiconductor detectors (D1 and D2 both based on ion implantation of 10B inside the aluminum metallic contact. The first detector shows a high leakage current after the implantation and low signal to noise ratio. However, improvements concerning the implantation parameters and the distance between the implanted 10B thermal neutron converter layer and the active pn-junction have led to low leakage current and thus to higher signal to noise ratio. This proves the strength of this new method of realizing sensitive SiC-based thermal neutron detectors.

  16. Linear electronics for Si-detectors and its energy calibration for use in heavy ion experiments

    CERN Document Server

    Taccetti, N; Carraresi, L; Bini, M; Casini, G; Ciaranfi, R; Giuntini, L; Maurenzig, P R; Montecchi, M; Olmi, A; Pasquali, G; Piantelli, S; Stefanini, A A

    2003-01-01

    The design and implementation of linear electronics based on small-size, low-power charge preamplifiers and shaping amplifiers, used in connection with Si-detector telescopes employed in heavy ion experiments, are presented. Bench tests and 'under beam' performances are discussed. In particular, the energy calibration and the linearity test of the overall system (Si-detector and linear and digital conversion electronics) has been performed with a procedure which avoids the pulse height defect problems connected with the detection of heavy ions. The procedure, basically, consists of using bursts of MeV protons, releasing up to GeV energies inside the detector, with low ionization density.

  17. Linear electronics for Si-detectors and its energy calibration for use in heavy ion experiments

    Science.gov (United States)

    Taccetti, N.; Poggi, G.; Carraresi, L.; Bini, M.; Casini, G.; Ciaranfi, R.; Giuntini, L.; Maurenzig, P. R.; Montecchi, M.; Olmi, A.; Pasquali, G.; Piantelli, S.; Stefanini, A. A.

    2003-01-01

    The design and implementation of linear electronics based on small-size, low-power charge preamplifiers and shaping amplifiers, used in connection with Si-detector telescopes employed in heavy ion experiments, are presented. Bench tests and "under beam" performances are discussed. In particular, the energy calibration and the linearity test of the overall system (Si-detector and linear and digital conversion electronics) has been performed with a procedure which avoids the pulse height defect problems connected with the detection of heavy ions. The procedure, basically, consists of using bursts of MeV protons, releasing up to GeV energies inside the detector, with low ionization density.

  18. One-cm-thick Si detector at LHe temperature

    Energy Technology Data Exchange (ETDEWEB)

    Braggio, C. [Dipartimento di Fisica, Universita di Ferrara, Via Saragat 1, 44100 Ferrara (Italy)], E-mail: braggio@pd.infn.it; Bressi, G. [INFN, Sez. di Pavia, Via Bassi 6, 27100 Pavia (Italy); Carugno, G. [INFN, Sez. di Padova, Via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [Laboratori Nazionali di Legnaro, Via dell' Universita 1, 35020 Legnaro (Italy); Serafin, A. [Dipartimento di Fisica, Universita di Padova, Via Marzolo 8, 35131 Padova (Italy)

    2007-10-11

    A silicon p-i-n diode of thickness 1 cm has been studied experimentally at liquid helium temperature. This preliminary study is aimed at the construction of a much bigger detector to detect low energy neutrino events.

  19. Investigation of temperature dependent barrier height of Au/ZnO/Si schottky diodes

    International Nuclear Information System (INIS)

    In this study, temperature dependent current-voltage (I-V) measurements have been performed to investigate the inhomogeneity in the temperature dependent barrier heights of Au/ZnO/Si Schottky barrier diode in the temperature range 150 - 400K. The room temperature values for ideality factor and barrier height were found to be 2.9 and 0.60 eV respectively indicating the inhomogenity in the barrier heights of grown samples. The Richardson plot and ideality factor verses barrier height graph were also drawn to verified the discontinuity between Au and ZnO. This barrier height inhomogenity was explained by applying Gaussian distribution model. The extrapolation of the linear Fap (n) plot to n= 1 has given a homogeneous barrier height of approximately 1.1 eV. Fap versus 1/T plot was drawn to obtain the values of mean barrier height for Au/ZnO/Si Schottky diode (1.1 eV) and standard deviation(ds) (0.02 V) at zero bais. (author)

  20. Calibration of diffusion barrier charcoal detectors and application to radon sampling in dwellings

    Energy Technology Data Exchange (ETDEWEB)

    Montero C, M.E.; Colmenero S, L.; Villalba, L.; Saenz P, J.; Cano J, A.; Moreno B, A.; Renteria V, M.; Herrera P, E.F. [Cento de Investigacion en Materiales Avanzados, S. C. Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, (Mexico); Cruz G, S. De la [Facultad de Enfermeria y Nutriologia, Universidad Autonoma de Chihuahua, Av. Politecnico Nacional 2714, Chihuahua, (Mexico); Lopez M, A. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, 11801 Mexico D.F. (Mexico)

    2003-07-01

    Some calibration conditions of diffusion barrier charcoal canister (DBCC) detectors for measuring radon concentration in air were studied. A series of functional expressions and graphs were developed to describe relationship between radon concentration in air and the activity adsorbed in DBCC, when placed in small chambers. A semi-empirical expression for the DBCC calibration was obtained, based on the detector integration time and the adsorption coefficient of radon on activated charcoal. Both, the integration time for 10 % of DBCC of the same batch, and the adsorption coefficient of radon for the activated charcoal used in these detectors, were experimentally determined. Using these values as the calibration parameters, a semi-empirical calibration function was used for the interpretation of the radon activities in the detectors used for sampling more than 200 dwellings in the major cities of the state of Chihuahua, Mexico. (Author)

  1. Effect of SiO$_{2}$ passivating layer in segmented silicon planar detectors on the detector response

    CERN Document Server

    Verbitskaya, Elena; Eremin, Vladimir; Golubkov, S; Konkov, K; Roe, Shaun; Ruggiero, G; Sidorov, A; Weilhammer, Peter

    2004-01-01

    Silicon detectors with a fine segmentation (micropixel and microstrip) are the main type of detectors used in the inner trackers of LHC experiments. Due to the high luminosity of the LHC machines they are required to have a fast response to fit the short shaping time of 25 ns and to be radiation hard. Evaluation of silicon microstrip detectors developed for the ATLAS silicon tracker and carried out under collaboration of CERN and PTI has shown the reversal of the pulse polarity in the detector response to short- range radiation. Since the negative signal is of about 30% of the normal positive one, the effect strongly reduces the charge collection efficiency in irradiated detectors. The investigation presents the consideration on the origin of a negative response in Si microstrip detectors and the experimental proof of the model. The study of the effect has been carried out using "baby" strip detectors with a special design: each strip has a window in a metallization, which covers the p/sup +/ implant. The sca...

  2. Spontaneously intermixed Al-Mg barriers enable corrosion-resistant Mg/SiC multilayer coatings

    Science.gov (United States)

    Soufli, Regina; Fernández-Perea, Mónica; Baker, Sherry L.; Robinson, Jeff C.; Alameda, Jennifer; Walton, Christopher C.

    2012-07-01

    Magnesium/silicon carbide (Mg/SiC) has the potential to be the best-performing reflective multilayer coating in the 25-80 nm wavelength region but suffers from Mg-related corrosion, an insidious problem which completely degrades reflectance. We have elucidated the origins and mechanisms of corrosion propagation within Mg/SiC multilayers. Based on our findings, we have demonstrated an efficient and simple-to-implement corrosion barrier for Mg/SiC multilayers. The barrier consists of nanometer-scale Mg and Al layers that intermix spontaneously to form a partially amorphous Al-Mg layer and is shown to prevent atmospheric corrosion while maintaining the unique combination of favorable Mg/SiC reflective properties.

  3. Study the radiation damage effects in Si microstrip detectors for future HEP experiments

    Science.gov (United States)

    Lalwani, Kavita; Jain, Geetika; Dalal, Ranjeet; Ranjan, Kirti; Bhardwaj, Ashutosh

    2016-07-01

    Silicon (Si) detectors are playing a key role in High Energy Physics (HEP) experiments due to their superior tracking capabilities. In future HEP experiments, like upgrade of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC), CERN, the silicon tracking detectors will be operated in a very intense radiation environment. This leads to both surface and bulk damage in Si detectors, which in turn will affect the operating performance of Si detectors. It is important to complement the measurements of the irradiated Si strip detectors with device simulation, which helps in understanding of both the device behavior and optimizing the design parameters needed for the future Si tracking system. An important ingredient of the device simulation is to develop a radiation damage model incorporating both bulk and surface damage. In this work, a simplified two-trap model is incorporated in device simulation to describe the type-inversion. Further, an extensive simulation of effective doping density as well as electric field profile is carried out at different temperatures for various fluences.

  4. Resistance of 4H-SiC Schottky barriers at high forward-current densities

    International Nuclear Information System (INIS)

    The resistance of Schottky barriers based on 4H-SiC is experimentally determined at high forward-current densities. The measured resistance is found to be significantly higher than the resistance predicted by classical mechanisms of electron transport in Schottky contacts. An assumption concerning the crucial contribution of the tunnel-transparent intermediate oxide layer between the metal and semiconductor to the barrier resistance is proposed and partially justified

  5. Investigation on the preparation of Si/mullite/Yb_2Si_2O_7 environmental barrier coatings onto silicon carbide

    Institute of Scientific and Technical Information of China (English)

    许越; 闫钊通

    2010-01-01

    With the development of aero-engine,gas import temperatures of hot section structural materials are increasingly higher.Metal alloy materials due to the rapidly decreased mechanical properties at relative high temperature are gradually replaced with silicon-based non-oxide silicon carbide ceramics.However,silicon carbide ceramic materials tend to spall and deform in engine combustion environment,need environmental barrier coatings for the protection of the matrix.The preparation of Si/mullite/Yb2Si2O7 envir...

  6. Performance of a 4H-SiC Schottky diode as a compact sized detector for neutron pulse form measurements

    International Nuclear Information System (INIS)

    4H-silicon carbide (4H-SiC) detectors are desirable for neutron pulse form measurement for their compact size, excellent radiation resistance and hydrogen free composition. The aim of this study is to investigate the use of a 4H-SiC detector to measure the pulse form of a neutron burst. A 4H-SiC detector is fabricated and tested in the pulsed neutron field of the Chinese Fast Burst Reactor II (CFBR II). Important parameters such as the breeding period and the FWHM of the neutron pulse are derived from the experimental result of the 4H-SiC detector. These parameters agree well with those from a plastic scintillator detector. The divergences are only 0.5%, demonstrating that the 4H-SiC detector can yield a high fidelity time profile of the CFBR II pulse. The difference in peak centroid of alpha spectra is negligible for the 4H-SiC detector even after 18 reactor pulses (a neutron fluence of 8.41×1012 cm−2), confirming the excellent radiation hardness of the 4H-SiC detector in pulsed neutron field. This study therefore indicates that 4H-SiC detectors can be usable as a compact sized detector to measure neutron pulses. - Highlight: • A 4H-SiC detector has been developed as a monitor for reactor neutron pulses for the first time. • The 4H-SiC detector can yield a high fidelity time profile of the Chinese Fast Burst Reactor II (CFBR II) pulse. • The difference in peak centroid of alpha spectra is negligible for the 4H-SiC detector even after 18 reactor pulses (8.41×1012 n/cm2)

  7. Direct probing of Schottky barriers in Si nanowire Schottky barrier field effect transistors.

    Science.gov (United States)

    Martin, Dominik; Heinzig, Andre; Grube, Matthias; Geelhaar, Lutz; Mikolajick, Thomas; Riechert, Henning; Weber, Walter M

    2011-11-18

    This work elucidates the role of the Schottky junction in the electronic transport of nanometer-scale transistors. In the example of Schottky barrier silicon nanowire field effect transistors, an electrical scanning probe technique is applied to examine the charge transport effects of a nanometer-scale local top gate during operation. The results prove experimentally that Schottky barriers control the charge carrier transport in these devices. In addition, a proof of concept for a reprogrammable nonvolatile memory device based on band bending at the Schottky barriers will be shown.

  8. New development of highly sensitive sintered LiF;Mg,Cu,Na,Si TL detector

    International Nuclear Information System (INIS)

    A highly sensitive pellet-type LiF:Mg,Cu,Na,Si TL detector has been newly developed. The TL sensitivity of this new TL detector was about 30 times higher than that of the TLD-100 by light integration measurements. The optimum concentrations of dopants for a pellet-type LiF:Mg,Cu,Na,Si TL detector were investigated as Mg: 0.2 mol%, Cu: 0.05 mol%, Na: 0.9 mol% and Si: 0.9 mol%. The observed glow curve structure of the detector was suitable for practical TLD on the grounds of its significantly low level of ratio namely, height of the high temperature peak / height of the main dosimetric peak (P5/P4). Reusability study of the detector was carried out for 10 cycles of reuse. The results show that the coefficients of variation for each detector separately did not exceed 0.016, and for all 10 detectors collectively was 0.0054

  9. The ArduSiPM a compact trasportable Software/Hardware Data Acquisition system for SiPM detector

    CERN Document Server

    Bocci, Valerio; Iacoangeli, Francesco; Nuccetelli, Massimo; Recchia, Luigi

    2014-01-01

    The acquisition of a single Silicon Photomultiplier require multiple and expensive electronics modules as : preamplifier, discriminator, bias voltage power supply, temperature monitor, Scalers, Analog to Digital Converter and Time to Digital Converter . The developed ArduSiPM is a compact cost effective and easily replicable Hardware software module for SiPM detector readout. The ArduSiPM uses an Arduino DUE (an open Software/Hardware board based on an ARM Cortex-M3 microcontroller) as processor board and a piggyback custom designed board (Shield), these are controlled by custom developed software and interface. The Shield contains different electronics features both to monitor, to set and to acquire the SiPM signals using the microcontroller board. The shield embed a controlled bias voltage power supply, a fast voltage preamplifier, a programmable fast discriminator to generate over threshold digital pulse , a peak hold to measure the pulse height, a temperature monitor system, a scaler to monitor over thres...

  10. Device Physics Analysis of Parasitic Conduction Band Barrier Formation in SiGe HBTs

    Science.gov (United States)

    Roenker, K. P.; Alterovitz, S. A.

    2000-01-01

    This paper presents a physics-based model describing the current-induced formation of a parasitic barrier in the conduction band at the base collector heterojunction in npn SiGe heterojunction bipolar transistors (HBTs). Due to the valence band discontinuity DELTA E(sub v), hole injection into the collector at the onset of base pushout is impeded, which gives rise to formation of a barrier to electron transport which degrades the device's high frequency performance. In this paper, we present results from an analytical model for the height of the barrier calculated from the device's structure as a function of the collector junction bias and collector current density.

  11. Development of High Resolution Si Strip Detectors for Experiments at High Luminosity at the LHC

    CERN Multimedia

    2002-01-01

    % RD-20 \\\\ \\\\ Recent studies indicate that good tracking near the interaction region in LHC experiments will be crucial to fully exploit the physics potential of this machine up to the highest luminosities. It is believed that Si strip detectors are among the best candidates to survive in the experimental environment imposed by the high energy, high luminosity and the severe radiation levels expected. It is therefore proposed to perform a systematic study of the feasibility of using Si strip detectors and suitably designed front-end electronics for tracking in LHC experiments. Issues discussed here are possible physics applications, requirements and design characteristics for Si strip detectors and front-end electronics and cooling. An R\\&D programme for the coming two years is described.

  12. Novel Gas Barrier SiOC Coating to PET Bottles through a Hot Wire CVD Method

    Directory of Open Access Journals (Sweden)

    Masaki Nakaya

    2016-01-01

    Full Text Available In an attempt to enhance the gas barrier enhancement of plastic containers such as poly(ethylene terephthalate bottles, a novel method was found using a hot wire CVD technique, where tantalum wire is heated and exposed to a gas flow of vinyl silane. The resultant SiOC thin film was confirmed to characteristically contain Si-Si bonds in its surface and demonstrate a remarkably and highly practical decrease of the permeation of various gas through poly(ethylene terephthalate bottles.

  13. Development of an angled Si-PM-based detector unit for positron emission mammography (PEM) system

    Science.gov (United States)

    Nakanishi, Kouhei; Yamamoto, Seiichi

    2016-11-01

    Positron emission mammography (PEM) systems have higher sensitivity than clinical whole body PET systems because they have a smaller ring diameter. However, the spatial resolution of PEM systems is not high enough to detect early stage breast cancer. To solve this problem, we developed a silicon photomultiplier (Si-PM) based detector unit for the development of a PEM system. Since a Si-PM's channel is small, Si-PM can resolve small scintillator pixels to improve the spatial resolution. Also Si-PM based detectors have inherently high timing resolution and are able to reduce the random coincidence events by reducing the time window. We used 1.5×1.9×15 mm LGSO scintillation pixels and arranged them in an 8×24 matrix to form scintillator blocks. Four scintillator blocks were optically coupled to Si-PM arrays with an angled light guide to form a detector unit. Since the light guide has angles of 5.625°, we can arrange 64 scintillator blocks in a nearly circular shape (a regular 64-sided polygon) using 16 detector units. We clearly resolved the pixels of the scintillator blocks in a 2-dimensional position histogram where the averages of the peak-to-valley ratios (P/Vs) were 3.7±0.3 and 5.7±0.8 in the transverse and axial directions, respectively. The average energy resolution was 14.2±2.1% full-width at half-maximum (FWHM). By including the temperature dependent gain control electronics, the photo-peak channel shifts were controlled within ±1.5% with the temperature from 23 °C to 28 °C. With these results, in addition to the potential high timing performance of Si-PM based detectors, our developed detector unit is promising for the development of a high-resolution PEM system.

  14. Stress-directed compositional patterning of SiGe substrates for lateral quantum barrier manipulation

    International Nuclear Information System (INIS)

    While vertical stacking of quantum well and dot structures is well established in heteroepitaxial semiconductor materials, manipulation of quantum barriers in the lateral directions poses a significant engineering challenge. Here, we demonstrate lateral quantum barrier manipulation in a crystalline SiGe alloy using structured mechanical fields to drive compositional redistribution. To apply stress, we make use of a nano-indenter array that is pressed against a Si0.8Ge0.2 wafer in a custom-made mechanical press. The entire assembly is then annealed at high temperatures, during which the larger Ge atoms are selectively driven away from areas of compressive stress. Compositional analysis of the SiGe substrates reveals that this approach leads to a transfer of the indenter array pattern to the near-surface elemental composition, resulting in near 100% Si regions underneath each indenter that are separated from each other by the surrounding Si0.8Ge0.2 bulk. The “stress transfer” process is studied in detail using multiscale computer simulations that demonstrate its robustness across a wide range of applied stresses and annealing temperatures. While the “Si nanodot” structures formed here are not intrinsically useful as quantum structures, it is anticipated that the stress transfer process may be modified by judicious control of the SiGe film thickness and indenter array pattern to form more technologically useful structures

  15. Fabrication of 4H-SiC Schottky barrier diodes with high breakdown voltages

    CERN Document Server

    Kum, B H; Shin, M W; Park, J D

    1999-01-01

    This paper discusses the fabrication and the breakdown characteristics of 4H-SiC Schottky barrier diodes (SBDs). Optimal processing conditions for the ohmic contacts were extracted using the transmission-line method (TLM) and were applied to the device fabrication. The Ti/4H-SiC SBDs with Si sub x B sub y passivation showed a maximum reverse breakdown voltage of 268 V with a forward current density as high as 70 mA/cm sup 2 at a forward voltage of 2 V. The breakdown of the Pt. 4H-SiC SBDs without any passivation occurred at near 110 V. It is concluded that the breakdown enhancement in the Ti/4H-SiC SBDs can be attributed to the passivation; otherwise, excess surface charge near the edge of the Schottky contact would lead to electric fields of sufficient magnitude to cause field emission.

  16. Atomic and electronic structure of ultrathin fluoride barrier layers at the oxide/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, L; Montecchi, M; Nannarone, S [Department of Materials and Environmental Engineering, University of Modena and Reggio Emilia, Via Vignolese 905, I-41125 Modena (Italy); Boscherini, F [Department of Physics, University of Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy)

    2011-09-07

    A SrF{sub 2} ultrathin barrier layer on Si(001) is used to form a sharp interface and block reactivity and intermixing between the semiconductor and a Yb{sub 2}O{sub 3} overlayer. Yb{sub 2}O{sub 3}/Si(001) and Yb{sub 2}O{sub 3}/SrF{sub 2}/Si(001) interfaces grown in ultra high vacuum by molecular beam epitaxy are studied by photoemission and x-ray absorption fine structure. Without the fluoride interlayer, Yb{sub 2}O{sub 3}/Si(001) presents an interface reacted region formed by SiO{sub x} and/or silicate compounds, which is about 9 A thick and increases up to 14-15 A after annealing at 500-700 {sup 0}C. A uniform single layer of SrF{sub 2} molecules blocks intermixing and reduces the oxidized Si region to 2.4 A after deposition and to 3.5 A after annealing at 500 {sup 0}C. In both cases we estimate a conduction band offset and a valence band offset of {approx} 1.7 eV and 2.4 eV between the oxide and Si, respectively. X-ray absorption fine structure measurements at the Yb L{sub III} edge suggest that the Yb oxide films exhibit a significant degree of static disorder with and without the fluoride barrier. Sr K edge measurements indicate that the ultrathin fluoride films are reacted, with the formation of bonds between Si and Sr; the Sr-Sr and Sr-F interatomic distances in the ultrathin fluoride barrier film are relaxed to the bulk value.

  17. Project and construction of a spectrometer for alpha particles using surface barrier detectors

    International Nuclear Information System (INIS)

    The project, construction, tests and some applications of a system for alpha and beta spectrometry, using surface barrier detector are described. The device includes a solid state detector ORTEC-Series F coupled to a system for amplifying the charges produced by passage of an ionizing particle through the detector. The amplifying system is composed by a charge sensitive pre-amplifier, which employs an operational amplifier CA 3140, and a low noise linear amplifier, which is based on the operational amplifiers CA 3140 and LM 301. The pre-amplifier stage input impedance is on the order of TΩ and produces output pulses which heights are proportional to total charge produced by passage of particle through the detector sensitive volume. The main advantage to use charge sensitive system lies in obtention of independent pulse heights of the distributed capacity of connecting cable between the detector and the pre-amplifier. The total system amplification ca reach a maximum of 50.000 in the linear region. Pulses are analysed in a multichannel system ORTEC, model 6240. The amplifier system is easily constructed and low cost using components available in the national market, and it can be employed with ionization chambers, proportional counters, scitillation counters and semiconductor detectors. The results of spectrometer application for alpha spectrometry of AM241 source were compared to systems made with imported stages. (Author)

  18. High-Operating-Temperature Barrier Infrared Detector with Tailorable Cutoff Wavelength

    Science.gov (United States)

    Ting, David Z.; Hill, Cory, J.; Soibel, Alexander; Bandara, Sumith V.; Gunapala, Sarath D.

    2011-01-01

    A mid-wavelength infrared (MWIR) barrier photodetector is capable of operating at higher temperature than the prevailing MWIR detectors based on InSb. The standard high-operating-temperature barrier infrared detector (HOT-BIRD) is made with an InAsSb infrared absorber that is lattice-matched to a GaSb substrate, and has a cutoff wavelength of approximately 4 microns. To increase the versatility and utility of the HOT-BIRD, it is implemented with IR absorber materials with customizable cutoff wavelengths. The HOT-BIRD can be built with the quaternary alloy GaInAsSb as the absorber, GaAlSbAs as the barrier, on a lattice-matching GaSb substrate. The cutoff wavelength of the GaInAsSb can be tailored by adjusting the alloy composition. To build a HOT-BIRD requires a matching pair of absorber and barrier materials with the following properties: (1) their valence band edges must be approximately the same to allow unimpeded hole flow, while their conduction band edges should have a large difference to form an electron barrier; and (2) the absorber and the barrier must be respectively lattice-matched and closely lattice-matched to the substrate to ensure high material quality and low defect density. To make a HOT-BIRD with cutoff wavelength shorter than 4 microns, a GaInAsSb quaternary alloy was used as the absorber, and a matching GaAlSbAs quaternary alloy as the barrier. By changing the alloy composition, the band gap of the quaternary alloy absorber can be continuously adjusted with cutoff wavelength ranging from 4 microns down to the short wavelength infrared (SWIR). By carefully choosing the alloy composition of the barrier, a HOT-BIRD structure can be formed. With this method, a HOT-BIRD can be made with continuously tailorable cutoff wavelengths from 4 microns down to the SWIR. The HOT-BIRD detector technology is suitable for making very-large-format MWIR/SWIR focal plane arrays that can be operated by passive cooling from low Earth orbit. High-operating temperature

  19. Electrical Properties of the Pulsed-Laser Deposited Surface-Barrier Structures Based on p-Si

    Science.gov (United States)

    Avjyan, K.; Khachatryan, A.; Matevosyan, L.; Vardanyan, G.; Panosyan, Zh.; Yengibaryan, Ye.

    Surface-barrier structures based on p-Si where fabricated by pulsed-laser deposition method. Electrical properties (current-voltage and capacitance-voltage) of these structures were studied. It is shown, that the forward current ((+) on p-Si) varies as a J=J0exp(eU/nkT) and surface-barrier structures based on high-resistivity p-Si are light-sensitive.

  20. SiC-based Photo-detectors for UV, VUV, EUV and Soft X-ray Detection

    Science.gov (United States)

    Yan, Feng

    2006-01-01

    A viewgraph presentation describing an ideal Silicon Carbide detector for ultraviolet, vacuum ultraviolet, extreme ultraviolet and soft x-ray detection is shown. The topics include: 1) An ideal photo-detector; 2) Dark current density of SiC photodiodes at room temperature; 3) Dark current in SiC detectors; 4) Resistive and capacitive feedback trans-impedance amplifier; 5) Avalanche gain; 6) Excess noise; 7) SNR in single photon counting mode; 8) Structure of SiC single photon counting APD and testing structure; 9) Single photon counting waveform and testing circuit; 10) Amplitude of SiC single photon counter; 11) Dark count of SiC APD photon counters; 12) Temperature-dependence of dark count rate; 13) Reduce the dark count rate by reducing the breakdown electric field; 14) Spectrum range for SiC detectors; 15) QE curves of Pt/4H-SiC photodiodes; 16) QE curve of SiC; 17) QE curves of SiC photodiode vs. penetration depth; 18) Visible rejection of SiC photodiodes; 19) Advantages of SiC photodiodes; 20) Competitors of SiC detectors; 21) Extraterrestrial solar spectra; 22) Visible-blind EUV detection; 23) Terrestrial solar spectra; and 24) Less than 1KeV soft x-ray detection.

  1. High-voltage breakdown studies on Si microstrip detectors

    CERN Document Server

    Albergo, S; Azzi, P; Babucci, E; Bacchetta, N; Bader, A J; Bagliesi, G; Basti, A; Biggeri, U; Bilei, G M; Bisello, D; Boemi, D; Bosi, F; Borrello, L; Bozzi, C; Braibant, S; Breuker, Horst; Bruzzi, Mara; Buffini, A; Busoni, S; Calefato, G; Candelori, A; Caner, A; Castaldi, R; Castro, A; Catacchini, E; Checcucci, B; Ciampolini, P; Civinini, C; Creanza, D; D'Alessandro, R; Da Rold, M; Demaria, N; De Palma, M; Dell'Orso, R; Marina, R D; Dutta, S; Eklund, C; Peisert, Anna; Feld, L; Fiore, L; Focardi, E; French, M; Freudenreich, Klaus; Fürtjes, A; Giassi, A; Giorgi, M A; Giraldo, A; Glessing, B; Gu, W H; Hall, G; Hammarström, R; Hebbeker, T; Hrubec, Josef; Muhtinen, M; Kaminski, A; Karimäki, V; Saint-Koenig, M; Krammer, Manfred; Lariccia, P; Lenzi, M; Loreti, M; Lübelsmeyer, K; Lustermann, W; Mättig, P; Maggi, G; Mannelli, M; Mantovani, G C; Marchioro, A; Mariotti, C; Martignon, G; McEvoy, B; Meschini, M; Messineo, A; My, S; Paccagnella, A; Palla, Fabrizio; Pandoulas, D; Papi, A; Parrini, G; Passeri, D; Pieri, M; Piperov, S; Potenza, R; Radicci, V; Raffaelli, F; Raymond, M; Santocchia, A; Schmitt, B; Selvaggi, G; Servoli, L; Sguazzoni, G; Siedling, R; Silvestris, L; Skog, K; Starodumov, Andrei; Stavitski, I; Stefanini, G; Tempesta, P; Tonelli, G; Tricomi, A; Tuuva, T; Vannini, C; Verdini, P G; Viertel, Gert M; Zie, Z; Li Ya Hong; Watts, S; Wittmer, B

    1999-01-01

    The breakdown performance of CMS barrel module prototype detectors and test devices with single and multi-guard structures were studied before and after neutron irradiation up to 2-10/sup 14/ 1 MeV equivalent neutrons. Before irradiation avalanche breakdown occurred at the guard ring implant edges. We measured 100-300 V higher breakdown voltage values for the devices with multi-guard than for devices with single-guard ring, After irradiation and type inversion the breakdown was smoother than before irradiation and the breakdown voltage value increased to 500-600 V for most of the devices. (9 refs).

  2. Development of Si-based detectors for intermediate energy heavy-ion physics at a storage-ring accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Whitlow, H.J.; Jaworowski, J.; Leandersson, M.; El Bouanani, M. [Lund Institute of Technology, Solvegatan Lund, (Sweden). Department of Nuclear Physics; Jakobsson, B. [Lund Univ. (Sweden). Dept. of Cosmic and Subatomic Physics; Romanski, J.; Westerberg, L.; Van Veldhuizen, E.J. [Uppsala Univ. (Sweden); The Chicsi Collaboration

    1996-12-31

    Ultrahigh vacuum (UHV) compatible Si detectors are being developed by the CELSIUS Heavy lon Collaboration (CHIC) for measuring the energy and identity of Intermediate Mass Fragments (IMF) with Z {approx} 3 - 12 and energies of 0.7 - I 0 A MeV. Here we give an overview of the development of Si {delta}E-E detector telescopes and investigations on IMF identification based on the pulse shape from Si-detectors where the particles impinge on the rear-face of the detector. 9 refs., 4 figs.

  3. A conductive surface coating for Si-CNT radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Antonio, E-mail: antonio.valentini@ba.infn.it [Dipartimento di Fisica, Università degli Studi di Bari, Via Orabona 4, 70125 Bari (Italy); Valentini, Marco [INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Ditaranto, Nicoletta [Dipartimento di Chimica, Università degli Studi di Bari, Via Amendola 173, 70126 Bari (Italy); Melisi, Domenico [INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Aramo, Carla, E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, Antonio [CNR-SPIN U.O.S. di Napoli and Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Casamassima, Giuseppe [Dipartimento di Fisica, Università degli Studi di Bari, Via Orabona 4, 70125 Bari (Italy); INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Cilmo, Marco [INFN, Sezione di Napoli, and Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Fiandrini, Emanuele [INFN, Sezione di Perugia, and Dipartimento di Fisica, Università degli Studi di Perugia, Piazza Università 1, 06100 Perugia (Italy); Grossi, Valentina [INFN, Sezione di L’Aquila, and Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio 10 Coppito, 67100 L’Aquila (Italy); and others

    2015-08-01

    Silicon–Carbon Nanotube radiation detectors need an electrically conductive coating layer to avoid the nanotube detachment from the silicon substrate and uniformly transmit the electric field to the entire nanotube active surface. Coating material must be transparent to the radiation of interest, and must provide the drain voltage necessary to collect charges generated by incident photons. For this purpose various materials have been tested and proposed in photodetector and photoconverter applications. In this article interface properties and electrical contact behavior of Indium Tin Oxide films on Carbon Nanotubes have been analyzed. Ion Beam Sputtering has been used to grow the transparent conductive layer on the nanotubes. The films were deposited at room temperature with Oxygen/Argon mixture into the sputtering beam, at fixed current and for different beam energies. Optical and electrical analyses have been performed on films. Surface chemical analysis and in depth profiling results obtained by X-ray Photoelectron Spectroscopy of the Indium Tin Oxide layer on nanotubes have been used to obtain the interface composition. Results have been applied in photodetectors realization based on multi wall Carbon Nanotubes on silicon. - Highlights: • ITO was deposited by Ion Beam Sputtering on MWCNT. • ITO on CNT makes an inter-diffusion layer of the order of one hundred nanometers. • Improvements of quantum efficiency of photon detectors based on CNT with ITO.

  4. A conductive surface coating for Si-CNT radiation detectors

    International Nuclear Information System (INIS)

    Silicon–Carbon Nanotube radiation detectors need an electrically conductive coating layer to avoid the nanotube detachment from the silicon substrate and uniformly transmit the electric field to the entire nanotube active surface. Coating material must be transparent to the radiation of interest, and must provide the drain voltage necessary to collect charges generated by incident photons. For this purpose various materials have been tested and proposed in photodetector and photoconverter applications. In this article interface properties and electrical contact behavior of Indium Tin Oxide films on Carbon Nanotubes have been analyzed. Ion Beam Sputtering has been used to grow the transparent conductive layer on the nanotubes. The films were deposited at room temperature with Oxygen/Argon mixture into the sputtering beam, at fixed current and for different beam energies. Optical and electrical analyses have been performed on films. Surface chemical analysis and in depth profiling results obtained by X-ray Photoelectron Spectroscopy of the Indium Tin Oxide layer on nanotubes have been used to obtain the interface composition. Results have been applied in photodetectors realization based on multi wall Carbon Nanotubes on silicon. - Highlights: • ITO was deposited by Ion Beam Sputtering on MWCNT. • ITO on CNT makes an inter-diffusion layer of the order of one hundred nanometers. • Improvements of quantum efficiency of photon detectors based on CNT with ITO

  5. Characteristics of fabricated SiC radiation detectors for fast neutron detection

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) is a promising material for neutron detection at harsh environments because of its capability to withstand strong radiation fields and high temperatures. Two PIN-type SiC semiconductor neutron detectors, which can be used for nuclear power plant (NPP) applications, such as in-core reactor neutron flux monitoring and measurement, were designed and fabricated. As a preliminary test, MCNPX simulations were performed to estimate reaction probabilities with respect to neutron energies. In the experiment, I-V curves were measured to confirm the diode characteristic of the detectors, and pulse height spectra were measured for neutron responses by using a 252Cf neutron source at KRISS (Korea Research Institute of Standards and Science), and a Tandem accelerator at KIGAM (Korea Institute of Geoscience and Mineral Resources). The neutron counts of the detector were linearly increased as the incident neutron flux got larger.

  6. Linear electronics for Si-detectors and its energy calibration for use in heavy ion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Taccetti, N.; Poggi, G.; Carraresi, L.; Bini, M.; Casini, G.; Ciaranfi, R.; Giuntini, L.; Maurenzig, P.R.; Montecchi, M.; Olmi, A.; Pasquali, G.; Piantelli, S.; Stefanini, A.A. E-mail: stefanini@fi.infn.it

    2003-01-11

    The design and implementation of linear electronics based on small-size, low-power charge preamplifiers and shaping amplifiers, used in connection with Si-detector telescopes employed in heavy ion experiments, are presented. Bench tests and 'under beam' performances are discussed. In particular, the energy calibration and the linearity test of the overall system (Si-detector and linear and digital conversion electronics) has been performed with a procedure which avoids the pulse height defect problems connected with the detection of heavy ions. The procedure, basically, consists of using bursts of MeV protons, releasing up to GeV energies inside the detector, with low ionization density.

  7. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    CERN Document Server

    Pasquali, G; Neindre, N Le; Ademard, G; Barlini, S; Bini, M; Bonnet, E; Borderie, B; Bougault, R; Bruno, M; Casini, G; Chbihi, A; Cinausero, M; Duenas, J A; Edelbruck, P; Frankland, J D; Gramegna, F; Gruyer, D; Kordyasz, A; Kozik, T; Lopez, O; Marchi, T; Morelli, L; Olmi, A; Ordine, A; Parlog, M; Piantelli, S; Poggi, G; Rivet, M F; Rosato, E; Salomon, F; Spadaccini, G; Stefanini, A A; Valdre, S; Vient, E; Twarog, T; Alba, R; Maiolino, C; Santonocito, D

    2014-01-01

    A study of identification properties of a Si-Si DE-E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the DE-E technique or Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the DE-E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher tha...

  8. Improved charge collection of the buried p-i-n a-Si:H radiation detectors

    International Nuclear Information System (INIS)

    Charge collection in hydrogenated amorphous silicon (a-Si:H) radiation detectors is improved for high LET particle detection by adding thin intrinsic layers to the usual p-i-n structure. This buried p-i-n structure enables us to apply higher bias and the electric field is enhanced. When irradiated by 5.8 MeV α particles, the 5.7 μm thick buried p-i-n detector with bias 300V gives a signal size of 60,000 electrons, compared to about 20,000 electrons with the simple p-i-n detectors. The improved charge collection in the new structure is discussed. The capability of tailoring the field profile by doping a-Si:H opens a way to some interesting device structures. 17 refs., 7 figs

  9. Comparison of bulk and epitaxial 4H-SiC detectors for radiation hard particle tracking

    CERN Document Server

    Quinn, T; Bruzzi, M; Cunningham, W; Mathieson, K; Moll, M; Nelson, T; Nilsson, H E; Pintillie, I; Rahman, M; Reynolds, L; Sciortino, S; Sellin, P J; Strachan, H; Svensson, B G; Vaitkus, J

    2003-01-01

    Measurements and simulations have been carried out using bulk and epitaxial SiC detectors. Samples were irradiated to fluences of around 10**1**4 hardrons/cm**2. Material of thickness 40um gave a charge collection efficiency of 100% dropping to around 60% at 100mum thickness. Detailed MEDICI simulations incorporated the main defect levels in SiC, the vanadium center, Z-center and a mid-gap level as measured by deep level transient spectroscopy and other techniques. Calculated recombination currents and charge collection efficiencies at varying fluences were comparable to experimental data. The study suggests that SiC detectors will operate up to fluences around 10 **1**6/cm**2 as required by future particle physics experiments.

  10. Dosimetric properties of sintered LiF : Mg,Cu,Na,Si TL detectors

    International Nuclear Information System (INIS)

    Selected dosimetric properties of sintered LiF : Mg,Cu,Na,Si detectors were studied. Solid LiF : Mg,Cu,Na,Si pellets of diameters 4.5 mm and thickness 0.9 mm, dark blue in colour, were obtained by cold pressing and sintering the powder at 820 deg. C. The dosimetric properties of the newly developed detectors were studied and compared with the properties of LiF : Mg,Cu,P pellets (MCP-N). The annealing conditions were the same as those used for MCP-N detectors. X-ray exposures were performed at the KAERI,Taejon,Korea, while other irradiation and readout were carried out at the INP in Krakow, Poland. The glow-curve structure of LiF : Mg,Cu,Na,Si pellets is found to be comparable to that of MCP-N (LiF : Mg,Cu,P) detectors but the absolute sensitivity is about 50% lower. The photon energy response after doses of X-rays of energy about 100 keV shows a decrease, similar to that in LiF : Mg,Cu,P. For lower energies the response is higher than that for LiF : Mg,Cu,P due to the presence of high-Z elements (Na,Cu, and Si). The relative TL efficiency after doses of alpha particles from an 214 Am source of the sintered LiF : Mg,Cu,Na,Si detectors is similar to that of MCP-N (LiF : Mg,Cu,P)

  11. Barrier controlled carrier trapping of extended defects in CdZnTe detector

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Rongrong [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Jie, Wanqi, E-mail: jwq@nwpu.edu.cn [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Xu, Yadong [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Yu, Hui; Zha, Gangqiang; Wang, Tao; Ren, Jie [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China)

    2015-09-11

    Transient current techniques using alpha particle source were utilized to study the influence of extended defects on the electron drift time and the detector performance of CdZnTe crystals. Different from the case of trapping through isolated point defect, a barrier controlled trapping model was used to explain the mechanism of carrier trapping at the extended defects. The effect of extended defects on the photoconductance was studied by laser beam induced transient current (LBIC) measurement. The results demonstrate that the Schottky-type depletion space charge region is induced at the vicinity of the extended defects, which further distorts the internal electric field distribution and affects the carrier trajectory in CdZnTe crystals. The relationship between the electron drift time and detector performance has been established. - Highlights: • The barrier controlled trapping model was developed around extended defects. • Electron mobility and E-field distribution were distorted by space charge depletion region. • Extended defects act as a recombination-activated region. • The relationships between extended defects and detector performance were established.

  12. Mechanical properties of SiOx gas barrier coatings on polyester films

    OpenAIRE

    Howells, D. G.; Henry, B. M.; Leterrier, Y.; Månson, J.-A. E.; Madocks, J.; Assender, H. E.

    2008-01-01

    This paper reports the impressive mechanical properties of 1 μm thick carbon-containing SiOx gas barrier coatings, characterised using the uniaxial fragmentation test. Such coatings have been found to act as excellent barriers to water vapour permeation partly because they can be made so thick without stress induced cracking. The impressive mechanical properties are thought to be due in part to the high amount of carbon they contain, which gives them a more organic character, as well as the f...

  13. Phase Transition Sensitive Schottky Barriers In Ga-Si(P Contacts

    Directory of Open Access Journals (Sweden)

    B.P. Modi

    2013-05-01

    Full Text Available Investigation and understanding of Schottky diodes continue to be interesting both for basic as well as technological points of view. Even now the evolutionary aspects of such contacts are not very clearly understood. In this paper it is shown that in respect of interfacial strain contribution to the barrier heights of such contacts semiconductor – liquid metal contacts are relatively better placed than solid semiconductor-solid metal contacts. Results on Ga-Si(p contact are discussed in this paper to show phase sensitive contribution to the barrier height of such Schottky contacts.

  14. Barrier distribution from 28Si+154Sm quasielastic scattering: Coupling effects in the fusion process

    Directory of Open Access Journals (Sweden)

    Kaur Gurpreet

    2016-01-01

    Full Text Available Barrier distribution for the 28Si+154Sm system has been extracted from large angle quasielastic scattering measurement to investigate the role of various channel couplings on fusion dynamics. The coupled channel calculations, including the collective excitation of the target and projectile, are observed to reproduce the experimental BD rather well. It seems that the role of neutron transfer, relative to collective excitation, is in fact weak in the 28Si+154Sm system even though it has positive Q-value for neutron transfer channels.

  15. Optimization of a bolometer detector for ITER based on Pt absorber on SiN membrane.

    Science.gov (United States)

    Meister, H; Eich, T; Endstrasser, N; Giannone, L; Kannamüller, M; Kling, A; Koll, J; Trautmann, T; Detemple, P; Schmitt, S

    2010-10-01

    Any plasma diagnostic in ITER must be able to operate at temperatures in excess of 200 °C and neutron loads corresponding to 0.1 dpa over its lifetime. To achieve this aim for the bolometer diagnostic, a miniaturized metal resistor bolometer detector based on Pt absorbers galvanically deposited on SiN membranes is being developed. The first two generations of detectors featured up to 4.5 μm thick absorbers. Results from laboratory tests are presented characterizing the dependence of their calibration constants under thermal loads up to 450 °C. Several detectors have been tested in ASDEX Upgrade providing reliable data but also pointing out the need for further optimization. A laser trimming procedure has been implemented to reduce the mismatch in meander resistances below 1% for one detector and the thermal drifts from this mismatch.

  16. Optimization of a bolometer detector for ITER based on Pt absorber on SiN membrane.

    Science.gov (United States)

    Meister, H; Eich, T; Endstrasser, N; Giannone, L; Kannamüller, M; Kling, A; Koll, J; Trautmann, T; Detemple, P; Schmitt, S

    2010-10-01

    Any plasma diagnostic in ITER must be able to operate at temperatures in excess of 200 °C and neutron loads corresponding to 0.1 dpa over its lifetime. To achieve this aim for the bolometer diagnostic, a miniaturized metal resistor bolometer detector based on Pt absorbers galvanically deposited on SiN membranes is being developed. The first two generations of detectors featured up to 4.5 μm thick absorbers. Results from laboratory tests are presented characterizing the dependence of their calibration constants under thermal loads up to 450 °C. Several detectors have been tested in ASDEX Upgrade providing reliable data but also pointing out the need for further optimization. A laser trimming procedure has been implemented to reduce the mismatch in meander resistances below 1% for one detector and the thermal drifts from this mismatch. PMID:21061487

  17. Optimization of a bolometer detector for ITER based on Pt absorber on SiN membrane

    International Nuclear Information System (INIS)

    Any plasma diagnostic in ITER must be able to operate at temperatures in excess of 200 deg. C and neutron loads corresponding to 0.1 dpa over its lifetime. To achieve this aim for the bolometer diagnostic, a miniaturized metal resistor bolometer detector based on Pt absorbers galvanically deposited on SiN membranes is being developed. The first two generations of detectors featured up to 4.5 μm thick absorbers. Results from laboratory tests are presented characterizing the dependence of their calibration constants under thermal loads up to 450 deg. C. Several detectors have been tested in ASDEX Upgrade providing reliable data but also pointing out the need for further optimization. A laser trimming procedure has been implemented to reduce the mismatch in meander resistances below 1% for one detector and the thermal drifts from this mismatch.

  18. FemtoDAQ: A Low-Cost Digitizer for SiPM-Based Detector Studies and its Application to the HAWC Detector Upgrade

    CERN Document Server

    Skulski, Wojtek; BenZvi, Segev

    2016-01-01

    The FemtoDAQ is a low-cost two channel data acquisition system which we have used to investigate the signal characteristics of silicon photomultipliers (SiPMs) coupled to fast scintillators. The FemtoDAQ system can also be used to instrument low cost moderate performance passive detectors, and is suitable for use in harsh environments (e.g., high altitude). The FemtoDAQ is being used as a SiPM test bench for the High Altitude Water Cherenkov (HAWC) Observatory, a TeV gamma ray detector located 4100 m above sea level. Planned upgrades to the HAWC array can benefit greatly from SiPMs, a robust, low-voltage, low-cost alternative to traditional vacuum photomultipliers. The FemtoDAQ is used to power the SiPM detector front end, bias the SiPM, and digitize the photosensor output in a single compact unit.

  19. As-Al recoil implantation through Si 3N 4 barrier layer

    Science.gov (United States)

    Godignon, P.; Morvan, E.; Montserrat, J.; Jordà, X.; Flores, D.; Rebollo, J.

    1999-01-01

    Al recoil implantation have been shown to be a possible alternative to direct Al ion implantation to avoid usual problems linked with Al sources. Poor efficiency of the recoil + annealing process is observed if no barrier or an oxyde screen layers are used. This problem can be solved using a Si 3N 4 screen layer. Then, P-N and N +/P/N structures can be obtained with deep low doped P-well with reduced thermal budget.

  20. As-Al recoil implantation through Si3N4 barrier layer

    International Nuclear Information System (INIS)

    Al recoil implantation have been shown to be a possible alternative to direct Al ion implantation to avoid usual problems linked with Al sources. Poor efficiency of the recoil + annealing process is observed if no barrier or an oxyde screen layers are used. This problem can be solved using a Si3N4 screen layer. Then, P-N and N+/P/N structures can be obtained with deep low doped P-well with reduced thermal budget

  1. The Aachen muon detector prototype. Muon measurement using scintillator tiles with SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Rebecca; Bretz, Thomas; Hebbeker, Thomas; Lauscher, Markus; Middendorf, Lukas; Niggemann, Tim; Peters, Christine; Schumacher, Johannes [III. Physikalisches Institut A, RWTH Aachen University (Germany); Collaboration: Pierre Auger-Collaboration

    2015-07-01

    Muons being produced in air showers of ultra high energy cosmic rays carry important information on their characteristics such as the mass of the primary particle and the first hadronic interactions at the highest energies. In the context of the Pierre Auger Observatory this upgrade would enable an enhanced primary particle identification as well as the verification of shower simulation models. For this purpose, a simple and robust detector design with scintillator tiles and SiPM readout is being developed, the Aachen Muon Detector (AMD). AMD could be situated below the SD tanks which would provide shielding from the electromagnetic part of the shower. In total, 64 scintillating tiles form the sensitive area of the detector. Wavelength-shifting fibres are inserted into the tiles in sigma-shape to collect the light and are coupled to optical fibres to guide it onto the photosensitive SiPMs. By reading out each SiPM individually, an excellent and low-background performance is expected. Currently the AMD prototype is being built in Aachen and in parallel SiPM and electronics characteristics are being evaluated.

  2. SiD Linear Collider Detector R&D, DOE Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Brau, James E. [Univ. of Oregon, Eugene, OR (United States); Demarteau, Marcel [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-05-15

    The Department of Energy’s Office of High Energy Physics supported the SiD university detector R&D projects in FY10, FY11, and FY12 with no-cost extensions through February, 2015. The R&D projects were designed to advance the SiD capabilities to address the fundamental questions of particle physics at the International Linear Collider (ILC): • What is the mechanism responsible for electroweak symmetry breaking and the generation of mass? • How do the forces unify? • Does the structure of space-time at small distances show evidence for extra dimensions? • What are the connections between the fundamental particles and forces and cosmology? Silicon detectors are used extensively in SiD and are well-matched to the challenges presented by ILC physics and the ILC machine environment. They are fast, robust against machine-induced background, and capable of very fine segmentation. SiD is based on silicon tracking and silicon-tungsten sampling calorimetry, complemented by powerful pixel vertex detection, and outer hadronic calorimetry and muon detection. Radiation hard forward detectors which can be read out pulse by pulse are required. Advanced calorimetry based on a particle flow algorithm (PFA) provides excellent jet energy resolution. The 5 Tesla solenoid is outside the calorimeter to improve energy resolution. PFA calorimetry requires fine granularity for both electromagnetic and hadronic calorimeters, leading naturally to finely segmented silicon-tungsten electromagnetic calorimetry. Since silicon-tungsten calorimetry is expensive, the detector architecture is compact. Precise tracking is achieved with the large magnetic field and high precision silicon microstrips. An ancillary benefit of the large magnetic field is better control of the e⁺e⁻ pair backgrounds, permitting a smaller radius beampipe and improved impact parameter resolution. Finally, SiD is designed with a cost constraint in mind. Significant advances and new capabilities have been made and

  3. Characterization of Si hybrid CMOS detectors for use in the soft x-ray band

    Science.gov (United States)

    Prieskorn, Zachary R.; Griffith, Christopher V.; Bongiorno, Stephen D.; Falcone, Abraham D.; Burrows, David N.

    2013-09-01

    We report on the characterization of four HAWAII Hybrid Si CMOS detectors (HCD) developed for use as X-ray detectors as part of a joint program between Penn State University and Teledyne Imaging Sensors (TIS). Interpixel capacitive crosstalk (IPC) has been measured for standard H1RG detectors as well as a specially developed H2RG that uses a unique bonding structure. The H2RG shows significant reduction in IPC, as reported by Griffith et al. 2012. Energy resolution at 1.5 & 5.9 keV was measured as well as read noise for each detector. Dark current as a function of temperature is reported from 150 - 210 K and dark current figures of merit are estimated for each detector. We also discuss upcoming projects including testing of a new HCD called the Speedster-EXD. This prototype detector will have a low noise, high gain CTIA to reduce IPC and read noise as well as in-pixel CDS and event flagging. In the coming year PSU and TIS will begin work on a project to incorporate CTIA and CDS circuitry into the ROIC of a HAWAII HCD like detector to satisfy the small pixel and high rate needs of future X-ray observatories.

  4. Schottky Barrier mapping of the W/Si diode using ballistic electron emission microscopy

    Science.gov (United States)

    Durcan, Christopher; Balsano, Robert; Pieniazek, Nicholas; Labella, Vincent

    2015-03-01

    The Schottky barrier of the W/Si(001) diode was investigated and spatially mapped at the nanoscale using ballistic electron emission microscopy (BEEM) and ballistic hole emission microscopy (BHEM). The miscibility of tungsten and silicon creates a thin silicide upon deposition with transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS) showing the changes in the silicide over several weeks. Using standard current voltage measurements there is no change in the charge transport across the diode during this time period. However, BEEM measurements do show dramatic changes to the transport of ballistic electrons over time with nanoscale resolution. Time dependent Schottky barrier maps are generated over a 1 μm x 1 μm area and provide valuable insight to the barrier height homogeneity, defect formation, and interfacial effects occurring in the diode.

  5. Effects of Grain Boundary Barrier in ZnO/Si Heterostructure

    Institute of Scientific and Technical Information of China (English)

    LIU Bing-Ce; LIU Ci-Hui; FV Zhu-Xi; Yi Bo

    2009-01-01

    The influence of ZnO microstructure on electrical barriers is investigated using capacitance-voltage (C-V), current-voltage (I-V) and deep level transient spectroscopy (DLTS) measurements. A deep level center located at EC- 0.24 eV obtained by DLTS in the ZnO films is an intrinsic defect related to Zni. The surface states in the ZnO grains that have acceptor behavior of capturing electrons from Zni defects result in the formation of grain barriers. In addition, we find that the current transport is dominated by grain barriers after annealing at 600°C at O2 ambient. With the increment of the annealing temperature, the current transport mechanism of ZnO/Si heterostructure is mainly dominated by thermo-emission.

  6. Reduction of Defects in SiOx Vapor Permeation Barriers on Polymer Substrates by Introducing a Sputtered Interlayer

    Science.gov (United States)

    Yun, Jungheum; Lee, Sunghun; Jeong, Yujeong; Lee, Hong-Rim; Kwon, Jung-Dae; Lee, Gun-Hwan

    2009-05-01

    This paper investigated the water-vapor permeability of silicon oxide (SiOx) barriers grown on poly(ethylene terephthalate) (PET) substrates using plasma-enhanced chemical vapor deposition (PECVD). The water-vapor transmission rate (WVTR) of granular-type SiOx barriers is dependent upon the density of microscopic pinholes in the barriers. A two-step hybrid process, consisting of (i) a sputtering stage for 10-nm-thick Al2O3 interlayer growth and (ii) a subsequent PECVD stage for thicker SiOx film growth, was proposed in this study. Granules and pinholes in SiOx barriers were simultaneously eliminated by introducing an Al2O3 interlayer on the PET surface prior to the SiOx PECVD process. Plasma-induced reconstruction of PET surfaces was prevented by applying a reactive sputtering process to grow the Al2O3 interlayer. High-quality barriers were developed from SiOx growth on the sputtered interlayer. Low WVTR values in the range of 10-3 g m-2 d-1 were recorded in tests using a MOCON instrument. The WVTR was two orders of magnitude smaller than that of conventional SiOx barriers directly grown on PET substrates without the Al2O3 interlayer.

  7. Improvements in Realizing 4H-SiC Thermal Neutron Detectors

    OpenAIRE

    Issa F.; Vervisch V.; Ottaviani L.; Szalkai D.; Vermeeren L.; Lyoussi A.; Kuznetsov A.; Lazar M.; Klix A.; Palais O.; Hallén A.

    2016-01-01

    In this work we presented two types of 4H-SiC semiconductor detectors (D1 and D2) both based on ion implantation of 10B inside the aluminum metallic contact. The first detector shows a high leakage current after the implantation and low signal to noise ratio. However, improvements concerning the implantation parameters and the distance between the implanted 10B thermal neutron converter layer and the active pn-junction have led to low leakage current and thus to higher signal to noise ratio. ...

  8. Characterization of Si Hybrid CMOS Detectors for use in the Soft X-ray Band

    OpenAIRE

    Prieskorn, Zachary; Griffith, Christopher V.; Bongiorno, Stephen D.; Falcone, Abraham D.; Burrows, David N.

    2013-01-01

    We report on the characterization of four Teledyne Imaging Systems HAWAII Hybrid Si CMOS detectors designed for X-ray detection. Three H1RG detectors were studied along with a specially configured H2RG. Read noise measurements were performed, with the lowest result being 7.1 e- RMS. Interpixel capacitive crosstalk (IPC) was measured for the three H1RGs and for the H2RG. The H1RGs had IPC upper limits of 4.0 - 5.5 % (up & down pixels) and 8.7 - 9.7 % (left & right pixels), indicating a clear a...

  9. Charge-sensitive poly-silicon TFT amplifiers for a-Si:H pixel particle detectors

    International Nuclear Information System (INIS)

    Prototype charge-sensitive poly-Si TFT amplifiers have been made for the amplification of signals (from an a-Si:H pixel diode used as an ionizing particle detector). They consist of a charge-sensitive gain stage, a voltage gain stage and a source follower output stage. The gain-bandwidth product of the amplifier is ∼ 300 MHz. When the amplifier is connected to a pixel detector of 0.2 pF, it gives a charge-to-voltage gain of ∼ 0.02 mV/electrons with a pulse rise time less than 100 nsec. An equivalent noise charge of the front-end TFT is ∼ 1000 electrons for a shaping time of 1 μsec

  10. RADIATION HARDNESS / TOLERANCE OF SI SENSORS / DETECTORS FOR NUCLEAR AND HIGH ENERGY PHYSICS EXPERIMENTS.

    Energy Technology Data Exchange (ETDEWEB)

    LI,Z.

    2002-09-09

    Silicon sensors, widely used in high energy and nuclear physics experiments, suffer severe radiation damage that leads to degradations in sensor performance. These degradations include significant increases in leakage current, bulk resistivity, and space charge concentration. The increase in space charge concentration is particularly damaging since it can significantly increase the sensor full depletion voltage, causing either breakdown if operated at high biases or charge collection loss if operated at lower biases than full depletion. Several strategies can be used to make Si detectors more radiation had tolerant to particle radiations. In this paper, the main radiation induced degradations in Si detectors will be reviewed. The details and specifics of the new engineering strategies: material/impurity/defect engineering (MIDE); device structure engineering (DSE); and device operational mode engineering (DOME) will be given.

  11. Application of a-Si:H radiation detectors in medical imaging

    International Nuclear Information System (INIS)

    Monte Carlo simulations of a proposed a-Si:H-based current-integrating gamma camera were performed. The analysis showed that the intrinsic resolution of such a camera was 1 ∼ 2.5 mm, which is somewhat better than that of a conventional gamma camera, and that the greater blurring, due to the detection of scattered γ-rays, could be reduced considerably by image restoration techniques. This proposed gamma camera would be useful for imaging shallow organs such as the thyroid. Prototype charge-storage a-Si:H pixel detectors for such a camera were designed, constructed and tested. The detectors could store signal charge as long as 5 min at -26C. The thermal generation current in reverse biased a-Si:H p-i-n photodetectors was investigated, and the Poole-Frenkel effect was found to be the most significant source of the thermal generation current. Based on the Poole-Frenkel effect, voltage- and time-dependent thermal generation current was modeled. Using the model, the operating conditions of the proposed a-Si:H gamma camera, such as the operating temperature, the operating bias and the γ-scan period, could be predicted. The transient photoconductive gain mechanism in various a-Si:H devices was investigated for applications in digital radiography. Using the a-Si:H photoconductors in n-i-n configuration in pixel arrays, enhancement in signal collection (more than 200 times higher signal level) can be achieved in digital radiography, compared to the ordinary p-i-n type a-Si:H x-ray imaging arrays

  12. Energy response and dose linearity of LiF:Mg, Cu, Na, Si TL detector

    International Nuclear Information System (INIS)

    The photon energy response of LiF : Mg, Cu, Na, Si thermoluminescence detector was measured using X-ray generator(20-118 keV) and 137Cs irradiator and its relative energy response appeared to be 0.825 for 20 keV photon normalized to that of 137Cs photon. The dose response was linear within the range of 10-4Gy - 20Gy, but shows sublinearity above 50Gy

  13. Modeling split gate tunnel barriers in lateral double top gated Si-MOS nanostructures

    Science.gov (United States)

    Shirkhorshidian, Amir; Bishop, Nathaniel; Young, Ralph; Wendt, Joel; Lilly, Michael; Carroll, Malcolm

    2012-02-01

    Reliable interpretation of quantum dot and donor transport experiments depends critically on understanding the tunnel barriers separating the localized electron state from the 2DEG regions which serve as source and drain. We analyze transport measurements through split gate point contacts, defined in a double gate enhancement mode Si-MOS device structure. We use a square barrier WKB model which accounts for barrier height dependence on applied voltage. This constant interaction model is found to produce a self-consistent characterization of barrier height and width over a wide range of applied source-drain and gate bias. The model produces similar results for many different split gate structures. We discuss this models potential for mapping between experiment and barrier simulations. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. Development of neutron detector using sensor type surface barrier with (n,p) and (n,α) converters

    International Nuclear Information System (INIS)

    A Si semiconductor detector, surface barrier type, with a slim film of a converter material capable to produce charged particles was used as a sensor of neutrons in an environment of a zero power reactor. Two types of converters were used to improve the detection efficiency: (1) the polyethylene, n(CH2), which produces recoil protons from the (n,p) interaction and, (2) the 10B which generates a particle from the (n,alpha) reaction. The optimal thickness of those converters was determined experimentally and specifically for the polyethylene a mathematical model R(ips) = εp · N0 ·(1-e-Σ·Χ) ·e -μ·Χ + εn · N0 · -Σ · Χ was used to fit to the experimental data. For the polyethylene converter the thickness was of 0.058 cm (62.64 mg.cm-2) while for the 10B it was equal to 6.55 [μm (1.54 mg.cm-2). The converter of polyethylene or 10B improved the detection efficiency to a factor of 4.7 and 3.0 respectively. The comparison of the spectrum of the background radiation with the spectra of the recoil protons and the a radiation from the 10B it was concluded that the polyethylene presented better performance than the 10B converter. (author)

  15. Neutron detector based on 4H-SiC Schottky diode

    International Nuclear Information System (INIS)

    A neutron detector exploiting the 6Li(n, α)3H reaction was fabricated by using semiconductor epitaxial 4H-SiC as the detection medium. This work aimed to develop neutron detector with increased resistance to radiation effects, thus it can be used in harsh environments. The 6LiF neutron converter layer was deposited by magnetron sputtering method and was characterized by scanning electron microscope (SEM). While the reverse voltages of the studied diode were tested from 10 V up to 600 V, the reverse current was below 6.4 nA, indicating a successful formation of Schottky contact between epitaxial 4H-SiC and Ni. The resolution factor for 5.486 MeV alpha particles was acquired as 4.5% by means of a 241Am source to this purpose. Response signals of neutron detector based on 4H-SiC Schottky diode to thermal neutron generated by critical assembly and slowed down by paraffin wax were obtained. (authors)

  16. SiC detectors for radiation sources characterization and fast plasma diagnostic

    Science.gov (United States)

    Cannavò, A.; Torrisi, L.

    2016-09-01

    Semiconductor detectors based on SiC have been investigated to characterize the radiations (photons and particles) emitted from different sources, such as radioactive sources, electron guns, X-ray tubes and laser-generated plasmas. Detectors show high response velocity, low leakage current, high energy gap and high radiation hardness. Their high detection efficiency permits to use the detectors in spectroscopic mode and in time-of-flight (TOF) approach, generally employed to monitor low and high radiation fluxes, respectively. Using the laser start signal, they permit to study the properties of the generated plasma in vacuum by measuring accurately the particle velocity and energy using pulsed lasers at low and high intensities. Possible applications will be reported and discussed.

  17. High resolution alpha particle detectors based on 4H-SiC epitaxial layer

    International Nuclear Information System (INIS)

    We fabricated and characterized 4H-SiC Schottky diodes as a spectrometric detector of alpha particles. A thin blocking contact of Ni/Au (15 nm) was used to minimize the influence on alpha particles energy. Current-voltage characteristics of the detector were measured and a low current density below 0.3 nAcm−2 was observed at room temperature. 239Pu241Am244Cm was used as a source of alpha particles within the energy range between 5.1 MeV and 5.8 MeV for detector testing. The charge collection efficiency close to 100 % at reverse bias exceeding 50 V was determined. The best spectrometric performance shows a pulse height spectrum at a reverse bias of 200 V giving an energy resolution of 0.25 % in the full width and half maximum for 5.486 MeV of 241Am

  18. Quantum efficiency of Si Hybrid CMOS detectors in the soft X-ray band

    Science.gov (United States)

    Prieskorn, Zachary; Bongiorno, Stephen; Burrows, David; Falcone, Abraham; Griffith, Christopher; Nikoleyczik, Jonathan; Wells, Mark; PSU X-ray Instrumentation Group Team

    2015-04-01

    X-ray sensitive Si Hybrid CMOS detectors (HCDs) will potentially replace X-ray CCDs in the focal planes of future X-ray observatories. HCDs improve on the performance of CCDs in numerous areas: faster read out time, windowed read out mode, less susceptibility to radiation & micrometeoroid damage, and lower power consumption. Understanding the detector quantum efficiency (QE) is critical for estimating the sensitivity of an X-ray instrument. We report on the QE for multiple energies in the soft X-ray band of four HCDs based on the Teledyne Imaging Sensors HyViSITM detectors. These detectors have Al optical blocking filters deposited directly on the Si substrate; these filters vary in thickness from 180 - 1000 Å. We estimate the QE with a 1D slab absorption model and find good agreement between the model and our results across an energy range from 0.677 - 8.05 keV. This work was supported by NASA Grants NNG05WC10G, NNX08AI64G, and NNX11AF98G.

  19. Characterization of Si Hybrid CMOS Detectors for use in the Soft X-ray Band

    Science.gov (United States)

    Prieskorn, Zachary; Griffith, C.; Bongiorno, S.; Falcone, A.; Burrows, D. N.

    2014-01-01

    In a joint program between Penn State University and Teledyne Imaging Sensors a soft X-ray detector based on the HAWAII Hybrid Si CMOS detector (HCD) has been developed. HCDs could potentially be the optimum detectors for the next generation of X-ray missions, especially those with focused optics and/or large effective area. These innovative detectors are active pixel sensors (APS) which allow a pixel to be read through individual in-pixel electronics, without the need to transfer charge across many pixels, in contrast to a CCD. They are made by bonding a Si absorbing layer to a pixelated CMOS readout, allowing the two layers to be optimized independently. The advantages of this design compared to CCDs are high speed timing 100 μs in full imaging mode), a flexible windowed readout to reduce pile-up, dramatically improved radiation hardness and resistance to micrometeoroid damage, and reduced power requirements. We present recent measurements of energy resolution, read noise, inter-pixel crosstalk, quantum efficiency, and dark current for four of these devices.

  20. Characteristics of fabricated si PIN-type radiation detectors on cooling temperature

    Science.gov (United States)

    Kim, Han Soo; Jeong, Manhee; Kim, Young Soo; Lee, Dong Hun; Cho, Seung Yeon; Ha, Jang Ho

    2015-06-01

    Si PIN photodiode radiation detectors with three different active areas (3×3 mm2, 5×5 mm2, and 10×10 mm2) were designed and fabricated at the Korea Atomic Energy Research Institute (KAERI) for low energy X- and gamma-ray detection. In Si-based semiconductor radiation detectors, one of the noise sources is thermal noise, which degrades their energy resolution performance. In this study, the temperature effects on the energy resolution were investigated using a 3×3 mm2 active area PIN photodiode radiation detector using a Thermoelectric Module (TEM) from room temperature to -23 °C. Energy resolutions from 25 keV auger electrons to 81 keV gamma-ray from a Ba-133 calibration source were measured and compared at every 10 °C interval. At -23 °C, energy resolutions were improved by 15.6% at 25 keV, 4.0% at 31 keV, and 1.2% at 81 keV in comparison with resolutions at room temperature. CsI(Tl)/PIN photodiode radiation detectors were also fabricated for relatively high energy gamma-ray detection. Energy resolutions for Cs-137, Co-60, and Na-22 sources were measured and compared with the spectral responsivity.

  1. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    International Nuclear Information System (INIS)

    A study of identification properties of a Si-Si ΔE-E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the ΔE-E technique or the Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the ΔE-E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher than at full depletion. Good isotopic identification via PSA has been obtained from a partially depleted detector, whose doping uniformity is not good enough for isotopic identification at full depletion. (orig.)

  2. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    Science.gov (United States)

    Pasquali, G.; Pastore, G.; Le Neindre, N.; Ademard, G.; Barlini, S.; Bini, M.; Bonnet, E.; Borderie, B.; Bougault, R.; Casini, G.; Chbihi, A.; Cinausero, M.; Dueñas, J. A.; Edelbruck, P.; Frankland, J. D.; Gramegna, F.; Gruyer, D.; Kordyasz, A.; Kozik, T.; Lopez, O.; Marchi, T.; Morelli, L.; Olmi, A.; Ordine, A.; Pârlog, M.; Piantelli, S.; Poggi, G.; Rivet, M. F.; Rosato, E.; Salomon, F.; Spadaccini, G.; Stefanini, A. A.; Valdrè, S.; Vient, E.; Twaróg, T.; Alba, R.; Maiolino, C.; Santonocito, D.

    2014-05-01

    A study of identification properties of a Si-Si ΔE- E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the ΔE- E technique or the Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the ΔE- E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher than at full depletion. Good isotopic identification via PSA has been obtained from a partially depleted detector, whose doping uniformity is not good enough for isotopic identification at full depletion.

  3. Energy measurement and fragment identification using digital signals from partially depleted Si detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, G.; Pastore, G.; Barlini, S.; Bini, M.; Poggi, G.; Stefanini, A.A.; Valdre, S. [Universita di Firenze, Dipartimento di Fisica, Sesto Fiorentino (Italy); INFN, Sezione di Firenze, Sesto Fiorentino (Italy); Le Neindre, N.; Bougault, R.; Lopez, O.; Vient, E. [ENSICAEN et Universite de Caen, LPC, IN2P3-CNRS, Caen-Cedex (France); Ademard, G.; Borderie, B.; Edelbruck, P.; Rivet, M.F.; Salomon, F. [Universite Paris-Sud 11, Institut de Physique Nucleaire, CNRS/IN2P3, Orsay cedex (France); Bonnet, E.; Chbihi, A.; Frankland, J.D.; Gruyer, D. [CEA/DSM-CNRS/IN2P3, GANIL, B.P. 5027, Caen cedex (France); Casini, G.; Olmi, A.; Piantelli, S. [INFN, Sezione di Firenze, Sesto Fiorentino (Italy); Cinausero, M.; Gramegna, F.; Marchi, T. [INFN-LNL Legnaro, Legnaro (Padova) (Italy); Duenas, J.A. [FCCEE Universidad de Huelva, Departamento de Fisica Aplicada, Huelva (Spain); Kordyasz, A. [University of Warsaw, Heavy Ion Laboratory, Warsaw (Poland); Kozik, T.; Twarog, T. [Institute of Nuclear Physics IFJ-PAN, Jagiellonian University, Krakow (Poland); Morelli, L. [INFN, Bologna (Italy); Universita di Bologna, Bologna (Italy); Ordine, A. [INFN, Sezione di Napoli, Napoli (Italy); Parlog, M. [ENSICAEN et Universite de Caen, LPC, IN2P3-CNRS, Caen-Cedex (France); ' ' Horia Hulubei' ' National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Rosato, E.; Spadaccini, G. [INFN, Sezione di Napoli, Napoli (Italy); Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica, Napoli (Italy); Alba, R.; Maiolino, C.; Santonocito, D. [INFN-LNS Catania, Catania (Italy); Collaboration: FAZIA Collaboration

    2014-05-15

    A study of identification properties of a Si-Si ΔE-E telescope exploiting an underdepleted residual-energy detector has been performed. Five different bias voltages have been used, one corresponding to full depletion, the others associated with a depleted layer ranging from 90% to 60% of the detector thickness. Fragment identification has been performed using either the ΔE-E technique or the Pulse Shape Analysis (PSA). Both detectors are reverse mounted: particles enter from the low field side, to enhance the PSA performance. The achieved charge and mass resolution has been quantitatively expressed using a Figure of Merit (FoM). Charge collection efficiency has been evaluated and the possibility of energy calibration corrections has been considered. We find that the ΔE-E performance is not affected by incomplete depletion even when only 60% of the wafer is depleted. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds are higher than at full depletion. Good isotopic identification via PSA has been obtained from a partially depleted detector, whose doping uniformity is not good enough for isotopic identification at full depletion. (orig.)

  4. Influence of solvothermal synthesis conditions in BiSI nanostructures for application in ionizing radiation detectors

    Science.gov (United States)

    Aguiar, I.; Mombrú, M.; Pérez Barthaburu, M.; Bentos Pereira, H.; Fornaro, L.

    2016-02-01

    BiSI belongs to the A V B VI C VII chalcohalides group of compounds. These compounds show several interesting properties such as ferroelectricity, piezoelectricity along the c axis, and photoconductivity. Moreover, BiSI is a potential semiconductor material for room-temperature gamma and x-ray detection, given its band gap of 1.57 eV and its high density, 6.41 g cm-3. In this work we present BiSI nanostructures synthesized by the solvothermal method with the intention of using them for ionizing radiation detection. The solvent was varied to study its influence in morphology, particle size and size distribution. Three different conditions were tested, using either water, monoethylene glycol and a mixture of both solvents. Nanostructures were characterized by XRD to determine the phase obtained and reaction completeness; TEM was used to observe nanostructures morphology, size, size distribution and crystallinity; and finally FT-IR diffuse reflectance was used to study monoethylene glycol presence in the samples. Nanorods in the range of 100-200 nm width were obtained in all samples, but round nanoparticles of around 10 nm in diameter were also detected in samples synthesized only with monoethylene glycol. Samples synthesized in monoethylene glycol were used to fabricate pellets to construct detectors. The detectors responded to ionizing radiation and a resistivity in the order of 1013 Ω cm was estimated. This work proposes, to our knowledge, the first study of BiSI for its application in ionizing radiation detection.

  5. Time over threshold readout method of SiPM based small animal PET detector

    International Nuclear Information System (INIS)

    Complete text of publication follows. The aim of the work was to design a readout concept for silicon photomultiplier (SiPM) sensor array used in small animal PET scanner. The detector module consist of LYSO 35x35 scintillation crystals, 324 SiPM sensors (arranged in 2x2 blocks and those quads in a 9x9 configuration) and FPGA based readout electronics. The dimensions of the SiPM matrix are area: 48x48 mm2 and the size of one SiPM sensor is 1.95x2.2 mm2. Due to the high dark current of the SiPM, conventional Anger based readout method does not provide sufficient crystal position maps. Digitizing the 324 SiPM channels is a straightforward way to obtain proper crystal position maps. However handling hundreds of analogue input channels and the required DSP resources cause large racks of data acquisition electronics. Therefore coding of the readout channels is required. Proposed readout method: The coding of the 324 SiPMs consists two steps: Step 1) Reduction of the channels from 324 to 36: Row column readout, SiPMs are connected to each other in column by column and row-by row, thus the required channels are 36. The dark current of 18 connected SiPMs is small in off for identifying pulses coming from scintillating events. Step 2) Reduction of the 18 rows and columns to 4 channels: Comparators were connected to each rows and columns, and the level was set above the level of dark noise. Therefore only few comparators are active when scintillation light enters in the tile. The output of the comparator rows and columns are divided to two parts using resistor chains. Then the outputs of the resistor chains are digitized by a 4 channel ADC. However instead of the Anger method, time over threshold (ToT) was used. Figure 1 shows the readout concept of the SiPM matrix. In order to validate the new method and optimize the front-end electronics of the detector, the analogue signals were digitized before the comparators using a CAEN DT5740 32 channel digitizer, then the

  6. Extracting information from partially depleted Si detectors with digital sampling electronics

    Directory of Open Access Journals (Sweden)

    Pastore G.

    2015-01-01

    Full Text Available A study of the identification properties and of the energy response of a Si-Si-CsI(Tl ΔE-E telescope exploiting a partially depleted second Si stage has been performed. Five different bias voltages have been applied to the second stage of the telescope, one corresponding to full depletion, the others associated with a depleted layer ranging from 60% to 90% of the detector thickness. Fragment identification has been obtained using either the ΔE-E technique or the Pulse Shape Analysis (PSA. Charge collection efficiency has been evaluated. The ΔE-E performance is not affected by incomplete depletion. Isotopic separation capability improves at lower bias voltages with respect to full depletion, though charge identification thresholds increase.

  7. Development of SciFi/CheFi detector with SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Ken [Stefan Meyer Institute, Boltzmanngasse 3, 1090 Vienna (Austria)], E-mail: ken.suzuki@oeaw.ac.at; Buehler, Paul; Fossati, Stefan; Marton, Johann; Schafhauser, Matthias; Zmeskal, Johann [Stefan Meyer Institute, Boltzmanngasse 3, 1090 Vienna (Austria)

    2009-10-21

    A Multi-pixel Geiger-mode APD, often called a Silicon Photomultiplier (SiPM), is a new type of photon counting device made up of multiple APD pixels operated in the Geiger-mode, which started to replace the PMT in a certain parts of photodetection field. Stefan Meyer Institute in Vienna has been working on an evaluation of several kinds of SiPMs from different manufacturers with different sizes of cells, sensitive area. We operate SiPMs in combination with scintillating fiber and Cherenkov radiator to test its potential with special focus on its timing performance, compactness and low-cost. The detectors are going to be applied in experiments like FOPI, AMADEUS and PANDA.

  8. Uncooled Radiation Hard Large Area SiC X-ray and EUV Detectors and 2D Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, fabricate, characterize and commercialize large area, uncooled and radiative hard 4H-SiC EUV ? soft X-ray detectors capable of ultra...

  9. Fabrication and characteristics of a 4H-SiC junction barrier Schottky diode*

    Institute of Scientific and Technical Information of China (English)

    Chen Fengping; Zhang Yuming; Lü Hongliang; Zhang Yimen; Guo Hui; Guo Xin

    2011-01-01

    4H-SiC junction barrier Schottky (JBS) diodes with four kinds of design have been fabricated and characterized using two different processes in which one is fabricated by making the P-type ohmic contact of the anode independently, and the other is processed by depositing a Schottky metal multi-layer on the whole anode. The reverse performances are compared to find the influences of these factors. The results show that JBS diodes with field guard rings have a lower reverse current density and a higher breakdown voltage, and with independent Ptype ohmic contact manufacturing, the reverse performance of 4H-SiC JBS diodes can be improved effectively.Furthermore, the P-type ohmic contact is studied in this work.

  10. As-Al recoil implantation through Si{sub 3}N{sub 4} barrier layer

    Energy Technology Data Exchange (ETDEWEB)

    Godignon, P. E-mail: philippe@cnm.es; Morvan, E.; Montserrat, J.; Jorda, X.; Flores, D.; Rebollo, J

    1999-01-01

    Al recoil implantation have been shown to be a possible alternative to direct Al ion implantation to avoid usual problems linked with Al sources. Poor efficiency of the recoil + annealing process is observed if no barrier or an oxyde screen layers are used. This problem can be solved using a Si{sub 3}N{sub 4} screen layer. Then, P-N and N{sup +}/P/N structures can be obtained with deep low doped P-well with reduced thermal budget.

  11. High-barrier Schottky contact on n-type 4H-SiC epitaxial layer and studies of defect levels by deep level transient spectroscopy (DLTS)

    Science.gov (United States)

    Nguyen, Khai V.; Pak, Rahmi O.; Oner, Cihan; Mannan, Mohammad A.; Mandal, Krishna C.

    2015-08-01

    High barrier Schottky contact has been fabricated on 50 μm n-type 4H-SiC epitaxial layers grown on 350 μm thick substrate 8° off-cut towards the [11̅20] direction. The 4H-SiC epitaxial wafer was diced into 10 x 10 mm2 samples. The metal-semiconductor junctions were fabricated by photolithography and dc sputtering with ruthenium (Ru). The junction properties were characterized through current-voltage (I-V) and capacitance-voltage (C-V) measurements. Detectors were characterized by alpha spectroscopy measurements in terms of energy resolution and charge collection efficiency using a 0.1 μCi 241Am radiation source. It was found that detectors fabricated from high work function rare transition metal Ru demonstrated very low leakage current and significant improvement of detector performance. Defect characterization of the epitaxial layers was conducted by deep level transient spectroscopy (DLTS) to thoroughly investigate the defect levels in the active region. The presence of a new defect level induced by this rare transition metal-semiconductor interface has been identified and characterized.

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

    Science.gov (United States)

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

    2016-06-01

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

  13. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Energy Technology Data Exchange (ETDEWEB)

    Verbitskaya, Elena, E-mail: elena.verbitskaya@cern.ch [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Eremin, Vladimir; Zabrodskii, Andrei [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R. [CERN, CH-1211, Geneva 23 (Switzerland); Egorov, Nicolai [Research Institute of Material Science and Technology, 4 Passage 4806, Moscow, Zelenograd 124460 (Russian Federation); Härkönen, Jaakko [Helsinki Institute of Physics, P.O.Box 64 (Gustaf Hallströmin katu 2) FI-00014 University of Helsinki (Finland)

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×10{sup 16} p/cm{sup 2}. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment. - Highlights: • Si detectors irradiated in situ at 1.9 K by 23 GeV protons are further studied. • Trapping parameters are derived from the fits of collected charge vs. fluence data. • Acceptor-type defects are likely to be induced along with donor-type ones. • Trapping of holes has a dominating effect on the collected charge degradation. • New tests are planned to gain deeper insight

  14. A simple low-noise cryogenic preamplifier for silicon surface barrier detectors

    International Nuclear Information System (INIS)

    A simple-high resolution charge sensitive preamplifier for surface barrier detectors (SBD) is described which uses drain feedback for charge restoration. It is shown that electronic noise can be reduced from 5 keV for a standard SBD-preamplifier system to 0.5 keV if one cools the SBD to 77 K and the field effect transistor (FET) to about 100 K and if one uses a SBD-FET assembly which is free from microphonics. The performance is demonstrated by measuring proton induced X-rays of Mg which have an energy of 1.25 keV. This large noise reduction results also in an enhancement of timing resolution by a factor 3. (orig.)

  15. Design Optimization of Pixel Structure for α-Si based Uncooled Infrared Detector

    Directory of Open Access Journals (Sweden)

    Sudha Gupta

    2013-11-01

    Full Text Available In this paper authors present the design and simulation results achieved for pixel structure of amorphous Si (α-Si based bolometer array. Most uncooled IR detectors in the world are based on VOx material. But this is not a standard material in IC technology and has many inherent disadvantages. The α-Si, an alternative material with high TCR is becoming as popular. However, large TCR values, in this material are achieved only in films of high resistivity. To achieve TCR value more than 2.5%/K, α-Si film resistivity is ~ 80 ohms-cm. This gives rise to very large pixel resistance of the order of 100 Mega ohms depending upon the design of the leg structure. This high pixel resistance causes very large noise and hence lower sensitivity. If leg width or membrane thickness is increased in order to reduce the pixel resistance, then this results in higher thermal conductance which also decreases sensitivity. To overcome this problem, pixel structure is so designed that within a pixel, only part of the electrical conduction is through α-Si and rest is through metal. Simulation using Coventorware software has been done to optimize pixel resistance as well as thermal conductance through legs so that maximum sensitivity could be obtained. Optimization is also carried out in order to reduce sensitivity of pixel resistance to variation in material resistivity.

  16. Study of surface recombination on cleaved and passivated edges of Si detectors

    Science.gov (United States)

    Gaubas, E.; Ceponis, T.; Vaitkus, J. V.; Fadeyev, V.; Ely, S.; Galloway, Z.; F-W Sadrozinski, H.; Christophersen, M.; Phlips, B. F.; Gorelov, I.; Hoeferkamp, M.; Metcalfe, J.; Seidel, S.

    2016-03-01

    The effectiveness of the passivation of a cleaved boundary of large area strip detectors has been studied by using Al2O3 formed by atomic layer deposition technology for p-Si structures and Si x N y grown on n-Si by plasma enhanced chemical vapour deposition. The parameters of bulk and surface recombinations have been examined in a contactless mode implemented through analysis of the microwave-probed photoconductivity transients. Rather efficient and reproducible passivation, revealed through the reduction of surface recombination velocities from ˜2 × 104 to 5 × 103 cm s-1 for n-Si and from ˜2 × 104 to 3 × 102 cm s-1 for p-Si samples, has been obtained. The existence of trapping centres together with recombination defects has been revealed at the cleaved interface within the passivating layer. It has been revealed that the impact of surface recombination is negligible when bulk radiation defects are dominant in samples irradiated with fluences >1014 neq cm-2.

  17. Signal and noise analysis of a-Si:H radiation detector-amplifier system

    International Nuclear Information System (INIS)

    Hydrogenated amorphous silicon (a-Si:H) has potential advantages in making radiation detectors for many applications because of its deposition capability on a large-area substrate and its high radiation resistance. Position-sensitive radiation detectors can be made out of a 1d strip or a 2-d pixel array of a Si:H pin diodes. In addition, signal processing electronics can be made by thin-film transistors on the same substrate. The calculated radiation signal, based on a simple charge collection model agreed well with results from various wave length light sources and 1 MeV beta particles on sample diodes. The total noise of the detection system was analyzed into (a) shot noise and (b) 1/f noise from a detector diode, and (c) thermal noise and (d) 1/f noise from the frontend TFT of a charge-sensitive preamplifier. the effective noise charge calculated by convoluting these noise power spectra with the transfer function of a CR-RC shaping amplifier showed a good agreement with the direct measurements of noise charge. The derived equations of signal and noise charge can be used to design an a-Si:H pixel detector amplifier system optimally. Signals from a pixel can be readout using switching TFTs, or diodes. Prototype tests of a double-diode readout scheme showed that the storage time and the readout time are limited by the resistances of the reverse-biased pixel diode and the forward biased switching diodes respectively. A prototype charge-sensitive amplifier was made using poly-Si TFTs to test the feasibility of making pixel-level amplifiers which would be required in small-signal detection. The measured overall gain-bandwidth product was ∼400 MHz and the noise charge ∼1000 electrons at a 1 μsec shaping time. When the amplifier is connected to a pixel detector of capacitance 0.2 pF, it would give a charge-to-voltage gain of ∼0.02 mV/electron with a pulse rise time less than 100 nsec and a dynamic range of 48 dB

  18. SiPMs characterization and selection for the DUNE far detector photon detection system

    Science.gov (United States)

    Sun, Y.; Maricic, J.

    2016-01-01

    The Deep Underground Neutrino Experiment (DUNE) together with the Long Baseline Neutrino Facility (LBNF) hosted at the Fermilab will provide a unique, world-leading program for the exploration of key questions at the forefront of neutrino physics and astrophysics. CP violation in neutrino flavor mixing is one of its most important potential discoveries. Additionally, the experiment will determine the neutrino mass hierarchy and precisely measure the neutrino mixing parameters which may potentially reveal new fundamental symmetries of nature. Moreover, the DUNE is also designed for the observation of nucleon decay and supernova burst neutrinos. The photon detection (PD) system in the DUNE far detector provides trigger for cosmic backgrounds, enhances supernova burst trigger efficiency and improves the energy resolution of the detector. The DUNE adopts the technology of liquid argon time projection chamber (LArTPC) that requires the PD sensors, silicon photomultipliers (SiPM), to be carefully chosen to not only work properly in LAr temperature, but also meet certain specifications for the life of the experiment. A comprehensive testing of SiPMs in cryostat is necessary since the datasheet provided by the manufactures in the market does not cover this temperature regime. This paper gives the detailed characterization results of SenSL C-Series 60035 SiPMs, including gain, dark count rate (DCR), cross-talk and after-pulse rate. Characteristic studies on SiPMs from other vendors are also discussed in order to avoid any potential problems associated with using a single source. Moreover, the results of the ongoing mechanical durability tests are shown for the current candidate, SenSL B/C-Series 60035 SiPMs.

  19. Analytic fitting and simulation methods for characteristic X-ray peaks from Si-PIN detector

    International Nuclear Information System (INIS)

    A semi-empirical detector response function (DRF) model is established to fit characteristic X-ray peaks recorded in Si-PIN spectra, which is mainly composed of four components: a truncated step function, a Gaussian-shaped full-energy peak, a Gaussian-shaped Si escape peak and an exponential tail. A simple but useful statistical distribution-based analytic method (SDA) is proposed to achieve accurate values of standard deviation for characteristic X-ray peaks. And the values of the model parameters except for the standard deviation are obtained by weighted least-squares fitting of the pulse-height spectra from a number of pure-element samples. A Monte Carlo model is also established to simulate the X-ray measurement setup. The simulated flux spectrum can be transformed by Si-PIN detector response function to real pulse height spectrum as studied in this work. Finally, the fitting result for a copper alloy sample was compared with experimental spectra, and the validity of the present method was demonstrated. (authors)

  20. The residual stress instrument with optimized Si(220) monochromator and position-sensitive detector at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang-Hee [Korea Atomic Energy Research Institute, Yusung, Daejon 305-600 (Korea, Republic of); Moon, Myung-Kook [Korea Atomic Energy Research Institute, Yusung, Daejon 305-600 (Korea, Republic of)]. E-mail: moonmk@kaeri.re.kr; Em, Vyacheslav T. [Korea Atomic Energy Research Institute, Yusung, Daejon 305-600 (Korea, Republic of); Choi, Young-Hyun [Korea Atomic Energy Research Institute, Yusung, Daejon 305-600 (Korea, Republic of); Cheon, Jong-Kyu [Korea Atomic Energy Research Institute, Yusung, Daejon 305-600 (Korea, Republic of); Nam, Uk-Won [Korea Astronomy Observatory, Yusung, Daejon 305-348 (Korea, Republic of); Kong, Kyung-Nam [Korea Astronomy Observatory, Yusung, Daejon 305-348 (Korea, Republic of)

    2005-06-11

    An upgraded residual stress instrument at the HANARO reactor of the KAERI is described. A horizontally focusing bent perfect crystal Si(220) monochromator (instead of a mosaic vertical focusing Ge monochromator) is installed in a drum with a tunable (2{theta}{sub M}=0-60{sup o}) take-off angle/wavelength. A specially designed position-sensitive detector (60% efficiency for {lambda}=1.8A) with 200mm (instead of 100mm) high-active area is used. There are no Soller type collimators in the instrument. The minimum possible monochromator to sample distance, L{sub MS}=2m, and sample to detector distance, L{sub SD}=1.2m, were found to be optimal. The new PSD and bent Si(220) monochromator combined with the possibility of selecting an appropriate wavelength resulted in about a ten-fold gain in data collection rate. The optimal reflections of austenitic and ferritic steels, aluminum and nickel for stress measurements with a Si(220) monochromator were chosen experimentally. The ability of the instrument to make strain measurements deep inside the austenitic and ferritic steels has been tested. For the chosen reflections and wavelengths, no shift of peak position (apparent strain) was observed up to 56mm length of path.

  1. Characterization of new a-Si:H detectors fabricated from amorphous silicon deposited at high rate by helium enhanced PECVD

    International Nuclear Information System (INIS)

    This paper is concerned with the characterization of new detectors fabricated from a-Si:H films deposited at high rates through the dilution of SiH4 in helium. Rates of up to ten times (5.5 micrometer/h) that of the standard technique are obtained, allowing for the feasible fabrication of detectors having thickness up to 100 micrometers. The electrical characteristics (depletion voltage, residual space charge density) of the helium diluted material, have been investigated and compared to that of the standard material. The response of detectors, made from both materials, to 5.5 MeV alpha particles are compared. 6 figs., 5 tabs., 13 refs

  2. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters)

    Science.gov (United States)

    Sisniega, A.; Zbijewski, W.; Stayman, J. W.; Xu, J.; Taguchi, K.; Fredenberg, E.; Lundqvist, Mats; Siewerdsen, J. H.

    2016-01-01

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  3. Characterization of Si hybrid CMOS detectors for use in the soft X-ray band

    International Nuclear Information System (INIS)

    We report on the characterization of four Teledyne Imaging Systems HAWAII Hybrid Si CMOS detectors designed for X-ray detection. Three H1RG detectors were studied along with a specially configured H2RG. Read noise measurements were performed, with the lowest result being 7.1 e− RMS. Interpixel capacitive crosstalk (IPC) was measured for the three H1RGs and for the H2RG. The H1RGs had IPC upper limits of 4.0–5.5% (up and down pixels) and 8.7–9.7% (left and right pixels), indicating a clear asymmetry. Energy resolution is reported for two X-ray lines, 1.5 and 5.9 keV, at multiple temperatures between 150 and 210 K. The best resolution measured at 5.9 keV was 250 eV (4.2%) at 150 K, with IPC contributing significantly to this measured energy distribution. The H2RG, with a unique configuration designed to decrease the capacitive coupling between ROIC pixels, had an IPC of 1.8±1.0% indicating a dramatic improvement in IPC with no measurable asymmetry. We also measured dark current as a function of temperature for each detector. For the detector with the lowest dark current, at 150 K, we measured a dark current of 0.020±0.001 (e− s−1 pixel−1). There is also a consistent break in the fit to the dark current data for each detector. Above 180 K, all the data can be fit by the product of a power law in temperature and an exponential. Below 180 K the dark current decreases more slowly; a shallow power law or constant must be added to each fit, indicating a different form of dark current is dominant in this temperature regime. Dark current figures of merit at 293 K are estimated from the fit for each detector

  4. Annealing temperature and barrier thickness effect on the structural and optical properties of silicon nanocrystals/SiO2 superlattices

    International Nuclear Information System (INIS)

    The effect of the annealing temperature and the SiO2 barrier thickness of silicon nanocrystal (NC)/SiO2 superlattices (SLs) on their structural and optical properties is investigated. Energy-filtered transmission electron microscopy (TEM) revealed that the SL structure is maintained for annealing temperatures up to 1150 °C, with no variation on the nanostructure morphology for different SiO2 barrier thicknesses. Nevertheless, annealing temperatures as high as 1250 °C promote diffusion of Si atoms into the SiO2 barrier layers, which produces larger Si NCs and the loss of the NC size control expected from the SL approach. Complementary Raman scattering measurements corroborated these results for all the SiO2 and Si-rich oxynitride layer thicknesses. In addition, we observed an increasing crystalline fraction up to 1250 °C, which is related to a decreasing contribution of the suboxide transition layer between Si NCs and the SiO2 matrix due to the formation of larger NCs. Finally, photoluminescence measurements revealed that the emission of the superlattices exhibits a Gaussian-like lineshape with a maximum intensity after annealing at 1150 °C, indicating a high crystalline degree in good agreement with Raman results. Samples submitted to higher annealing temperatures display a progressive emission broadening, together with an increase in the central emission wavelength. Both effects are related to a progressive broadening of the size distribution with a larger mean size, in agreement with TEM observations. On the other hand, whereas the morphology of the Si NCs is unaffected by the SiO2 barrier thickness, the emission properties are slightly modified. These observed modifications in the emission lineshape allow monitoring the precipitation process of Si NCs in a direct non-destructive way. All these experimental results evidence that an annealing temperature of 1150 °C and 1-nm SiO2 barrier can be reached whilst preserving the SL structure, being thus

  5. Development of a SiPM-based PET detector using a digital positioning algorithm

    Science.gov (United States)

    Lee, Jin Hyung; Lee, Seung-Jae; An, Su Jung; Kim, Hyun-Il; Chung, Yong Hyun

    2016-05-01

    A decreased number of readout method is investigated here to provide precise pixel information for small-animal positron emission tomography (PET). Small-animal PET consists of eight modules, each being composed of a 3 × 3 array of 2 mm × 2 mm × 20 mm lutetium yttrium orthosilicate (LYSO) crystals optically coupled to a 2 × 2 array of 3 mm × 3 mm silicon photomultipliers (SiPMs). The number of readout channels is reduced by one-quarter that of the conventional method by applying a simplified pixel-determination algorithm. The performances of the PET system and detector module were evaluated with experimental verifications. In the results, all pixels of the 3 × 3 LYSO array were decoded well, and the performances of the PET detector module were measured.

  6. SiPMs characterization and selection for the DUNE far detector photon detection system

    CERN Document Server

    Sun, Yujing

    2015-01-01

    The Deep Underground Neutrino Experiment (DUNE) together with the Long Baseline Neutrino Facility (LBNF) hosted at the Fermilab will provide a unique, world-leading program for the exploration of key questions at the forefront of neutrino physics and astrophysics. CP violation in neutrino flavor mixing is one of its most important potential discoveries. Additionally, the experiment will determine the neutrino mass hierarchy and precisely measure the neutrino mixing parameters which may potentially reveal new fundamental symmetries of nature. Moreover, the DUNE is also designed for the observation of nucleon decay and supernova burst neutrinos. The photon detection (PD) system in the DUNE far detector provides trigger for cosmic backgrounds, enhances supernova burst trigger efficiency and improves the energy resolution of the detector. The DUNE adopts the technology of liquid argon time projection chamber (LArTPC) that requires the PD sensors, silicon photomultipliers (SiPM), to be carefully chosen to not only...

  7. Radiation stability of SiC-ion detectors to exposure by relativistic protons

    CERN Document Server

    Ivanov, A M; Davydov, D V; Savkina, N S; Lebedev, A A; Mironov, Y T; Ryabov, G A; Ivanov, E M

    2001-01-01

    Schottky diodes based on 6H-SiC epitaxial films are used. The structures are exposed to dose 3 x 10 sup 1 sup 4 cm sup - sup 2 of 1000 MeV protons. The effect of high energy protons is studied by means of precise alpha-spectrometry. Parameters of deep levels induced by protons are measured using the deep-level transient spectroscopy. The number of vacancies arising in the track of 1000 and 8 MeV proton is determined by TRIM program. Thickness of space charge region and the diffusion length for holes is determined before and after irradiation by fitting the experimental result of alpha-spectrometry and capacitance measurements. The results show insignificant changes of charges transport properties in SiC detectors

  8. A SiPM-based TOF-PET detector with high speed digital DRS4 readout

    Science.gov (United States)

    Ronzhin, A.; Albrow, M.; Los, S.; Martens, M.; Murat, P.; Ramberg, E.; Kim, H.; Chen, C.-T.; Kao, C.-M.; Niessen, K.; Zatserklyaniy, A.; Mazzillo, M.; Carbone, B.; Condorelli, G.; Fallica, G.; Piana, A.; Sanfilippo, D.; Valvo, G.; Ritt, S.

    2013-03-01

    We have developed γ-ray detectors with good time resolution, to supplement positron emission tomography (PET) with time of flight (TOF) for better localization of the positron annihilation. This will improve the quality of medical images and reduce exposure times. We report results of LYSO scintillating crystals (3×3×15 mm3) irradiated with a 22Na source and coupled to silicon photomultipliers (SiPMs) readout with a waveform digitizer. Improved time resolution, 188 ps FWHM, was obtained with the signal trimmed by a clipping capacitance.

  9. A SiPM-based TOF-PET detector with high speed digital DRS4 readout

    Energy Technology Data Exchange (ETDEWEB)

    Ronzhin, A., E-mail: ronzhin@fnal.gov [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Albrow, M.; Los, S.; Martens, M.; Murat, P.; Ramberg, E. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kim, H.; Chen, C.-T.; Kao, C.-M. [University of Chicago, Chicago, IL (United States); Niessen, K. [SUNY Buffalo, NY (United States); Zatserklyaniy, A. [University of California Santa Cruz, Santa Cruz, CA (United States); Mazzillo, M.; Carbone, B.; Condorelli, G.; Fallica, G.; Piana, A.; Sanfilippo, D.; Valvo, G. [STMicroelectronics, Catania 95121 (Italy); Ritt, S. [Paul Scherrer Institute, Villigen (Switzerland)

    2013-03-01

    We have developed γ-ray detectors with good time resolution, to supplement positron emission tomography (PET) with time of flight (TOF) for better localization of the positron annihilation. This will improve the quality of medical images and reduce exposure times. We report results of LYSO scintillating crystals (3×3×15 mm{sup 3}) irradiated with a {sup 22}Na source and coupled to silicon photomultipliers (SiPMs) readout with a waveform digitizer. Improved time resolution, 188 ps FWHM, was obtained with the signal trimmed by a clipping capacitance.

  10. High resolution detectors based on continuous crystals and SiPMs for small animal PET

    Energy Technology Data Exchange (ETDEWEB)

    Cabello, J. [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain); Barrillon, P. [Laboratoire de L' Accélérateur Linéaire (LAL), Orsay (France); Barrio, J. [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain); Bisogni, M.G.; Del Guerra, A. [Dipartimento di Fisica “E. Fermi“, Università di Pisa and INFN Pisa, Pisa (Italy); Lacasta, C. [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain); Rafecas, M. [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain); Departamento de Física Atómica, Nuclear y Molecular, Universitat de València, Valencia (Spain); Saikouk, H. [Laboratoire de Physique Nucléaire, Faculté des Sciences, Université Mohammed V-Agdal, Rabat (Morocco); Solaz, C.; Solevi, P. [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain); La Taille, C. de [Laboratoire de L' Accélérateur Linéaire (LAL), Orsay (France); Llosá, G., E-mail: gabriela.llosa@ific.uv.es [Instituto de Física Corpuscular, Universitat de València/CSIC, Valencia (Spain)

    2013-08-01

    Sensitivity and spatial resolution are the two main factors to maximize in emission imaging. The improvement of one factor deteriorates the other with pixelated crystals. In this work we combine SiPM matrices with monolithic crystals, using an accurate γ-ray interaction position determination algorithm that provides depth of interaction. Continuous crystals provide higher sensitivity than pixelated crystals, while an accurate interaction position determination does not degrade the spatial resolution. Monte Carlo simulations and experimental data show good agreement both demonstrating sub-millimetre intrinsic spatial resolution. A system consisting in two rotating detectors in coincidence is currently under operation already producing tomographic images.

  11. Active conductivity of plane two-barrier resonance tunnel structure as operating element of quantum cascade laser or detector

    Directory of Open Access Journals (Sweden)

    Ju.O. Set

    2011-06-01

    Full Text Available Within the model of rectangular potentials and different effective masses of electrons in different elements of plane two-barrier resonance tunnel structure there is developed a theory of spectral parameters of quasi-stationary states and active conductivity for the case of mono-energetic electronic current interacting with electromagnetic field. It is shown that the two-barrier resonance tunnel structure can be utilized as a separate or active element of quantum cascade laser or detector. For the experimentally studied In0.53Ga0.47As/In0.52Al0.48As nano-system it is established that the two-barrier resonance tunnel structure, in detector and laser regimes, optimally operates (with the biggest conductivity at the smallest exciting current at the quantum transitions between the lowest quasi-stationary states.

  12. Simulation of near-infrared photodiode detectors based onβ-FeSi2/4H-SiC heterojunctions

    Institute of Scientific and Technical Information of China (English)

    Pu Hong-Bin; He Xin; Quan Ru-Dai; Cao Lin; Chen Zhi-Ming

    2013-01-01

    In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide (β-FeSi2) as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type/β-FeSi2 absorption layer with a doping concentration of 1 x 1015 cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the/β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.

  13. The Development of 2700-3000 F Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Challenges and Opportunities

    Science.gov (United States)

    Zhu, Dongming

    2015-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is a key to enable the applications of the envisioned 2700-3000F EBC - CMC systems to help achieve next generation engine performance and durability goals. This paper will primarily address the performance requirements and design considerations of environmental barrier coatings for turbine engine applications. The emphasis is placed on current NASA candidate environmental barrier coating systems for SiCSiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. The efforts have been also directed to developing prime-reliant, self-healing 2700F EBC bond coat; and high stability, lower thermal conductivity, and durable EBC top coats. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, cyclic durability, erosion-impact resistance, and long-term system performance will be described. The research and development opportunities for turbine engine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be discussed.

  14. Tuning a Schottky barrier of epitaxial graphene/4H-SiC (0001) by hydrogen intercalation

    Energy Technology Data Exchange (ETDEWEB)

    Dharmaraj, P.; Justin Jesuraj, P.; Jeganathan, K., E-mail: kjeganathan@yahoo.com [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu (India)

    2016-02-01

    We report the electron transport properties of epitaxial graphene (EG) grown on 4H-SiC (0001) by low energy electron-beam irradiation. As-grown EG (AEG) on SiC interface exhibits rectifying current-voltage characteristics with a low Schottky barrier (SB) of 0.55 ± 0.05 eV and high reverse current leakage. The SB of AEG/SiC junction is extremely impeded by the Fermi level pinning (FLP) above the Dirac point due to charged states at the interface. Nevertheless, a gentle hydrogen intercalation at 900 °C enables the alleviation of both FLP and carrier scattering owing to the saturation of dangling bonds as evidenced by the enhancement of SB (0.75 ± 0.05 eV) and high electron mobility well excess of 6000 cm{sup 2} V{sup −1} s{sup −1}.

  15. 1024 × 1024 Si:As IBC detector arrays for JWST MIRI

    Science.gov (United States)

    Love, Peter J.; Hoffman, Alan W.; Lum, Nancy A.; Ando, Ken J.; Rosbeck, Joe; Ritchie, William D.; Therrien, Neil J.; Holcombe, Roger S.; Corrales, Elizabeth

    2005-08-01

    1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by RVS for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). MIRI provides imaging, coronagraphy, and low and medium resolution spectroscopy over the 5 - 28 μm band. The IBC devices are also suitable for other low-background applications. The Si:As IBC detectors have a pixel dimension of 25 μm and respond to infrared radiation between 5 and 28 μm, covering an important Mid-IR region beyond the 1 - 5 μm range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer Mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. We describe results of the development of a new 1024 × 1024 Si:As IBC array that responds with high quantum efficiency over the wavelength range 5 to 28 μm. The previous generation's largest, most sensitive infrared (IR) detectors at these wavelengths were the 256 × 256 / 30 μm pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument1. Detector performance results will be discussed, including relative spectral response, Responsive Quantum Efficiency (RQE) vs. detector bias, and dark current versus temperature. In addition, Sensor Chip Assembly (SCA) data will be presented from the first Engineering SCAs. The detector ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise of the "bare" MUX is less than 12 e- rms with Fowler-8 sampling at an operating temperature of 7 K. A companion paper by Craig McMurtry (University of Rochester) will discuss the details of SB305 MUX noise measurements2. Other features of the IBC array include 4 video outputs and a separate reference output with a frame rate of 0.36 Hz (2.75 sec frame time). Power dissipation is about 0.5 mW at a 0.36 Hz frame rate

  16. Monte Carlo semi-empirical model for Si(Li) x-ray detector: Differences between nominal and fitted parameters

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Pino, N.; Padilla-Cabal, F.; Garcia-Alvarez, J. A.; Vazquez, L.; D' Alessandro, K.; Correa-Alfonso, C. M. [Departamento de Fisica Nuclear, Instituto Superior de Tecnologia y Ciencias Aplicadas (InSTEC) Ave. Salvador Allende y Luaces. Quinta de los Molinos. Habana 10600. A.P. 6163, La Habana (Cuba); Godoy, W.; Maidana, N. L.; Vanin, V. R. [Laboratorio do Acelerador Linear, Instituto de Fisica - Universidade de Sao Paulo Rua do Matao, Travessa R, 187, 05508-900, SP (Brazil)

    2013-05-06

    A detailed characterization of a X-ray Si(Li) detector was performed to obtain the energy dependence of efficiency in the photon energy range of 6.4 - 59.5 keV, which was measured and reproduced by Monte Carlo (MC) simulations. Significant discrepancies between MC and experimental values were found when the manufacturer parameters of the detector were used in the simulation. A complete Computerized Tomography (CT) detector scan allowed to find the correct crystal dimensions and position inside the capsule. The computed efficiencies with the resulting detector model differed with the measured values no more than 10% in most of the energy range.

  17. Initial testing of a Si:As blocked-impurity-band (BIB) trap detector

    Science.gov (United States)

    Woods, Solomon I.; Kaplan, Simon G.; Jung, Timothy M.; Carter, Adriaan C.; Proctor, James E.

    2012-06-01

    We discuss the design, construction, and initial test results of a Si:As blocked-impurity-band (BIB) trap detector. The trap consists of two rectangular BIB devices configured in a v-shaped geometry. This trapping geometry is designed to ideally yield a minimum of 7 bounces before exit for incident light within an f/4 cone with 3 mm clear aperture. The individual BIB devices consist of 70 μm thick active layers with As doping near 1.7×1018 cm-3, and have dark currents of approximately 100 nA at an operating temperature of 9 K. A simple ray-tracing model of the trap, along with data on the quantum yield of typical BIB detector elements, indicates that it is possible to achieve an external quantum efficiency of > 0.99 over the 4 μm to 28 μm spectral range and significant suppression of the etalon fringes present in the spectral responsivity of a single element. We have made initial responsivity measurements of the trap compared to a calibrated 5 mm diameter pyroelectric detector over the 3 μm to 17 μm spectral range using the fiber-coupled output of a Fourier-transform spectrometer. We also discuss the results of comparison measurements between the trap detector and an absolute cryogenic radiometer viewing the output of a calibrated blackbody source at discrete filter bands from 5 μm to 11 μ. In initial testing the performance of the trap is limited by the poor performance of the individual BIB detectors, but the advantages of boosted quantum efficiency and suppressed etalon are realized by the trap.

  18. Investigation of the inhomogeneous barrier height of an Au/Bi4Ti3O12/n-Si structure through Gaussian distribution of barrier height

    Institute of Scientific and Technical Information of China (English)

    M.G(o)k(c)en; M.Y(i)ld(i)r(i)m

    2012-01-01

    A Au/Bi4Ti3O12/n-Si structure is fabricated in order to investigate its current voltage (I-V) characteristics in a temperature range of 300 K-400 K.Obtained I-V data are evaluated by the thermionic emission (TE) theory.Zero-bias barrier height (ΦB0) and ideality factor (n) calculated from I-V characteristics,are found to be temperature-dependent such that ΦB0 increases with temperature increasing,whereas n decreases.The obtained temperature dependence of ΦB0 and linearity in ΦB0 versus the n plot,together with a lower barrier height and Richardson constant values obtained from the Richardson plot,indicate that the barrier height of the structure is inhomogeneous in nature.Therefore,I-V characteristics are explained on the basis of Gaussian distribution of barrier height.

  19. Research Progress in Silicon Carbide Neutron Detector%SiC中子探测器的研究进展

    Institute of Scientific and Technical Information of China (English)

    胡青青; 杨俊; 刘国福; 罗晓亮

    2012-01-01

    相比于气体、闪烁体及常规半导体中子探测器,基于第三代半导体材料SiC的中子探测器具有体积小、响应快、位置分辨率好、抗高温和耐辐照等众多优点.其中抗高温和耐辐照是应用于核反应堆堆芯、高能物理试验和太空等高温高压以及强辐射环境下的中子探测器需要突破的瓶颈.论文总结和分析了SiC的材料特性,SiC中子探测器的结构、工作原理、国内外发展现状以及存在的问题,并对我国中子探测器的发展趋势进行了探讨.%The detectors which are based on the third era semiconductor material SiC offer several important advantages over gas, scintillator and conventional semiconductor neutron detectors, such as compact size, faster charge - collection times, better location and spatial resolution, temperature and radiation hardness et al. A detector capable of operating at elevated temperatures and in high radiation fields including nuclear reactors, high - energy physical experiment and outer space, is the chokepoint that neutron detector need to break through. This article introduces the properties of the epitaxial silicon carbide material, SiC neutron detector configuration , work principle, also summarizes and analyses recent researches and problems need to solve of SiC neutron detector at home and abroad. At last,discusses the developing direction of radiation detectors in the interior.

  20. Characterization of 600-μm-thick SI-GaAs detectors for medical imaging

    International Nuclear Information System (INIS)

    We present results of an experimental study concerning different semi-insulating GaAs (SI-GaAs) detectors of thickness 600 μm, aimed at testing their performance in terms of leakage current, breakdown voltage, charge collection efficiency (CCE) and energy resolution (ΔE/E), in view of their possible application to digital imaging in radiology and nuclear medicine. We have investigated the detection performance of detectors with different sizes of the Schottky contact pad (0.2-1.0 mm), using different gamma radioactive sources (241Am, 131Ba and 152Eu with peak energy 60, 81 and 122 keV, respectively) and a laser source (λ=813 nm, pulse width=43 ps, pulse energy 4 pJ). CCE values up to 80% and minimum ΔE/E of 6% at 60 keV were observed. For SI-GaAs Schottky diodes, evidence of the dependence of electrical and spectroscopic performance on the side of the pixel ('small pixel effect') is presented

  1. Charge transport in a-Si:H detectors: Comparison of analytical and Monte Carlo simulations

    International Nuclear Information System (INIS)

    To understand the signal formation in hydrogenated amorphous silicon (a-Si:H) p-i-n detectors, dispersive charge transport due to multiple trapping in a-Si:H tail states is studied both analytically and by Monte Carlo simulations. An analytical solution is found for the free electron and hole distributions n(x,t) and the transient current I(t) due to an initial electron-hole pair generated at an arbitrary depth in the detector for the case of exponential band tails and linear field profiles; integrating over all e-h pairs produced along the particle's trajectory yields the actual distributions and current; the induced charge Q(t) is obtained by numerically integrating the current. This generalizes previous models used to analyze time-of-flight experiments. The Monte Carlo simulation provides the same information but can be applied to arbitrary field profiles, field dependent mobilities and localized state distributions. A comparison of both calculations is made in a simple case to show that identical results are obtained over a large time domain. A comparison with measured signals confirms that the total induced charge depends on the applied bias voltage. The applicability of the same approach to other semiconductors is discussed

  2. Influence of dopants on the glow curve structure and energy dependence of LiF:Mg,Cu,Si detectors

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, Z., E-mail: zknez@irb.h [Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Ranogajec-Komor, M.; Miljanic, S. [Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Lee, J.I.; Kim, J.L. [Korea Atomic Energy Research Institute, P.O. Box 105 Yuseong, Daejon 305-600 (Korea, Republic of); Music, S. [Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia)

    2011-03-15

    LiF thermoluminescent material doped with Mg, Cu and Si recently developed by the Korea Atomic Energy Research Institute (KAERI) has shown very good dosimetric properties. Since the thermoluminescence in LiF was found to be dependent on the proper combination of dopants, the investigation of the concentration and type of dopants is very important in developing and characterisation of new TL materials. The aim of this work was to determine the influence of type and concentration of activators on the glow curve structure, sensitivity, reproducibility and on the photon energy response of LiF:Mg,Cu,Si detectors. The energy response was studied in air and on the ISO water phantom in the range of mean photon energies between 33 keV and 164 keV. The morphology and local chemical composition of LiF:Mg,Cu,Si detectors were examined using high resolution scanning electron microscopy (FE-SEM). The results show that type and concentration of activators influence the glow curve and sensitivity. Different dopant concentrations did not show influence on the photon energy response. The sensitivity of LiF:Mg,Cu,Si detector with dopant concentration of Mg = 0.35 mol%, Cu = 0.025 mol% and Si = 0.9 mol% was very high (up to 65 times higher than that of TLD-100). The photon energy response of LiF:Mg,Cu,Si detectors containing all three dopants in various concentrations is in accordance with the IAEA recommendations for individual monitoring.

  3. 6H-SiC Schottky barrier source/drain NMOSFET with field-induced source/drain extension

    Institute of Scientific and Technical Information of China (English)

    Tang Xiao-Yan; Zhang Yi-Men; Zhang Yu-Ming; Gao Jin-Xia

    2005-01-01

    A novel SiC Schottky barrier source/drain NMOSFET(SiC SBSD-NMOSFET) with field-induced source/drain(FISD) extension is proposed and demonstrated by numerical simulation for the first time. In the new device the FISD extension is induced by a metal field-plate lying on top of the passivation oxide, and the width of Schottky barrier is controllde by the metal field-plate. The new structure not only eliminates the effect of the significantly improves the on-state current. Moreover, the performance of the present device exhibits very weak dependence on the widths of sidewalls.

  4. A planar Al-Si Schottky barrier metal–oxide–semiconductor field effect transistor operated at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Purches, W. E. [School of Physics, UNSW, Sydney 2052 (Australia); Rossi, A.; Zhao, R. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Kafanov, S.; Duty, T. L. [School of Physics, UNSW, Sydney 2052 (Australia); Centre for Engineered Quantum Systems (EQuS), School of Physics, UNSW, Sydney 2052 (Australia); Dzurak, A. S. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia); Rogge, S.; Tettamanzi, G. C., E-mail: g.tettamanzi@unsw.edu.au [School of Physics, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia)

    2015-08-10

    Schottky Barrier-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.

  5. Schottky barrier height measurements of Cu/Si(001), Ag/Si(001), and Au/Si(001) interfaces utilizing ballistic electron emission microscopy and ballistic hole emission microscopy

    International Nuclear Information System (INIS)

    The Schottky barrier heights of both n and p doped Cu/Si(001), Ag/Si(001), and Au/Si(001) diodes were measured using ballistic electron emission microscopy and ballistic hole emission microscopy (BHEM), respectively. Measurements using both forward and reverse ballistic electron emission microscopy (BEEM) and (BHEM) injection conditions were performed. The Schottky barrier heights were found by fitting to a linearization of the power law form of the Bell-Kaiser BEEM model. The sum of the n-type and p-type barrier heights are in good agreement with the band gap of silicon and independent of the metal utilized. The Schottky barrier heights are found to be below the region of best fit for the power law form of the BK model, demonstrating its region of validity

  6. Design optimization of Pixel Structure for α-Si based uncooled Infrared detector

    Directory of Open Access Journals (Sweden)

    Sudha Gupta

    2013-12-01

    Full Text Available In this paper authors present the design and simulation results achieved for pixel structure of amorphous Si (α-Si based bolometer array. Most uncooled IR detectors in the world are based on VOx material. But this is not a standard material in IC technology and has many inherent disadvantages. The α-Si, an alternative material with high TCR is becoming as popular. However, large TCR values, in this material are achieved only in films of high resistivity. To achieve TCR value more than 2.5%/K, α-Si film resistivity is ~ 80 ohms-cm. This gives rise to very large pixel resistance of the order of 100 Mega ohms depending upon the design of the leg structure. This high pixel resistance causes very large noise and hence lower sensitivity. If leg width or membrane thickness is increased in order to reduce the pixel resistance, then this results in higher thermal conductance which also decreases sensitivity. To overcome this problem, pixel structure is so designed that within a pixel, only part of the electrical conduction is through α-Si and rest is through metal. Simulation using Coventorware software has been done to optimize pixel resistance as well as thermal conductance through legs so that maximum sensitivity could be obtained. Optimization is also carried out in order to reduce sensitivity of pixel resistance to variation in material resistivity.Defence Science Journal, 2013, 63(6, pp.581-588, DOI:http://dx.doi.org/10.14429/dsj.63.5758

  7. Plasma-polymerized SiOx deposition on polymer film surfaces for preparation of oxygen gas barrier polymeric films

    International Nuclear Information System (INIS)

    SiOx films were deposited on surfaces of three polymeric films, PET, PP, and Nylon; and their oxygen gas barrier properties were evaluated. To mitigate discrepancies between the deposited SiOx and polymer film, surface modification of polymer films was done, and how the surface modification could contribute to was discussed from the viewpoint of apparent activation energy for the permeation process. The SiOx deposition on the polymer film surfaces led to a large decrease in the oxygen permeation rate. Modification of polymer film surfaces by mans of the TMOS or Si-COOH coupling treatment in prior to the SiOx deposition was effective in decreasing the oxygen permeation rate. The cavity model is proposed as an oxygen permeation process through the SiOx-deposited Nylon film. From the proposed model, controlling the interface between the deposited SiOx film and the polymer film is emphasized to be a key factor to prepare SiOx-deposited polymer films with good oxygen gas barrier properties. (author)

  8. Status of HgCdTe Barrier Infrared Detectors Grown by MOCVD in Military University of Technology

    Science.gov (United States)

    Kopytko, M.; Jóźwikowski, K.; Martyniuk, P.; Gawron, W.; Madejczyk, P.; Kowalewski, A.; Markowska, O.; Rogalski, A.; Rutkowski, J.

    2016-09-01

    In this paper we present the status of HgCdTe barrier detectors with an emphasis on technological progress in metalorganic chemical vapor deposition (MOCVD) growth achieved recently at the Institute of Applied Physics, Military University of Technology. It is shown that MOCVD technology is an excellent tool for HgCdTe barrier architecture growth with a wide range of composition, donor /acceptor doping, and without post-grown annealing. The device concept of a specific barrier bandgap architecture integrated with Auger-suppression is as a good solution for high-operating temperature infrared detectors. Analyzed devices show a high performance comparable with the state-of-the-art of HgCdTe photodiodes. Dark current densities are close to the values given by "Rule 07" and detectivities of non-immersed detectors are close to the value marked for HgCdTe photodiodes. Experimental data of long-wavelength infrared detector structures were confirmed by numerical simulations obtained by a commercially available software APSYS platform. A detailed analysis applied to explain dark current plots was made, taking into account Shockley-Read-Hall, Auger, and tunneling currents.

  9. Status of HgCdTe Barrier Infrared Detectors Grown by MOCVD in Military University of Technology

    Science.gov (United States)

    Kopytko, M.; Jóźwikowski, K.; Martyniuk, P.; Gawron, W.; Madejczyk, P.; Kowalewski, A.; Markowska, O.; Rogalski, A.; Rutkowski, J.

    2016-06-01

    In this paper we present the status of HgCdTe barrier detectors with an emphasis on technological progress in metalorganic chemical vapor deposition (MOCVD) growth achieved recently at the Institute of Applied Physics, Military University of Technology. It is shown that MOCVD technology is an excellent tool for HgCdTe barrier architecture growth with a wide range of composition, donor/acceptor doping, and without post-grown annealing. The device concept of a specific barrier bandgap architecture integrated with Auger-suppression is as a good solution for high-operating temperature infrared detectors. Analyzed devices show a high performance comparable with the state-of-the-art of HgCdTe photodiodes. Dark current densities are close to the values given by "Rule 07" and detectivities of non-immersed detectors are close to the value marked for HgCdTe photodiodes. Experimental data of long-wavelength infrared detector structures were confirmed by numerical simulations obtained by a commercially available software APSYS platform. A detailed analysis applied to explain dark current plots was made, taking into account Shockley-Read-Hall, Auger, and tunneling currents.

  10. A space qualified thermal imaging system using a Pt Si detector array

    Science.gov (United States)

    Astheimer, Robert W.

    1989-01-01

    EDO Corporation, Barnes Engineering Division designed and constructed a high resolution thermal imaging system on contract to Lockheed for use in the SDI Star Lab. This employs a Pt Si CCD array which is sensitive in the spectral range of 3 to 5 microns. Star Lab will be flown in the Shuttle bay and consists basically of a large, reflecting, tracking telescope with associated sensors and electronics. The thermal imaging system is designed to operate in the focal plane of this telescope. The configuration of the system is illustrated. The telescope provides a collimated beam output which is focussed onto the detector array by a silicon objective lens. The detector array subtends a field of view of 1.6 degrees x 1.22 degrees. A beam switching mirror permits bypassing the large telescope to give a field of 4 degrees x 3 degrees. Two 8 position filter wheels are provided, and background radiation is minimized by Narcissus mirrors. The detector is cooled with a Joule-Thompson cryostat fed from a high pressure supply tank. This was selected instead of a more convenient closed-cycle system because of concern with vibration. The latter may couple into the extremely critical Starlab tracking telescope. The electronics produce a digitized video signal for recording. Offset and responsivity correction factors are stored for all pixels and these corrections are made to the digitized output in real time.

  11. Improved fitting of PIXE spectra: the Voigt profile and Si(Li) detector modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hildner, M.L. [Sandia National Labs., Livermore, CA (United States); Antolak, A.J. [Sandia National Labs., Livermore, CA (United States); Bench, G.S. [Lawrence Livermore National Lab., CA (United States)

    1996-04-11

    The true emitted X-ray lineshape as measured by a Si(Li) detector is the convolution of the intrinsic Lorentzian X-ray lineshape and the detector response function. We demonstrate the necessity of using the Voigt profile -the convolution of a Lorentzian and a Gaussian - to fit the full-energy peak portion of directly measured X-ray lines. By incorporating the Voigtian in our PIXE spectrum fitting code, PIXEF, we have found consistent improvement in the quality of fit and calculated elemental yields. We have also found that the Voigtian fit is required to give an accurate ratio of tail to peak intensity. We attribute the tail to a surface layer of incomplete charge collection (ICC) at the front of the detector. Although this model is improved by appropriately accounting for the loss of photoelectrons that travel back to the ICC layer after being emitted from the intrinsic region, it appears to fail when the full-energy peak is fit to a Gaussian. On the other hand, excellent agreement between the improved model and experiment is found when the full-energy peak is fit to a Voigtian. (orig.).

  12. Demonstration of a 4H SiC Betavoltaic Nuclear Battery Based on Schottky Barrier Diode

    Institute of Scientific and Technical Information of China (English)

    QIAO Da-Yong; YUAN Wei-Zheng; GAO Peng; YAO Xian-Wang; ZANG Bo; ZHANG Lin; GUO Hui; ZHANG Hong-Jian

    2008-01-01

    A 4H SiC betavoltaic nuclear battery is demonstrated. A Schottky barrier diode is utilized for carrier separation.Under illumination of Ni-63 source with an apparent activity of 4mCi/cm2, an open circuit voltage of 0.49 V and a short circuit current density of 29.44 nA/cm2 are measured. A power conversion effciency of 1.2% is obtained.The performance of the device is limited by low shunt resistance, backscattering and attenuation of electron energy in air and Schottky electrode. It is expected to be significantly improved by optimizing the design and processing technology of the device.

  13. Particle identification with the Silicon Transition Radiation Detector (SiTRD): State of art and future perspectives

    International Nuclear Information System (INIS)

    We are developing a novel Transition Radiation Detector (SiTRD) based on silicon strip detectors (SSDs) operated in a magnetic field region. In this way the trajectory of the radiating particle is deflected with respect to the Transition Radiation X-rays that are absorbed in a detector region far away from the particle track. The SiTRD combines the particle identification performance of a traditional TRD with the high-precision tracking capability of SSDs, and it can be suitable for both accelerator and cosmic ray experiments, whenever particle identification and momentum reconstruction are required. In this paper we will show the experimental results obtained with a reduced scale SiTRD prototype exposed to an electron-pion beam

  14. A SiPM-based ZnS:$^6$LiF scintillation neutron detector

    CERN Document Server

    Stoykov, A; Greuter, U; Hildebrandt, M; Schlumpf, N

    2014-01-01

    In the work presented here we built and evaluated a single-channel neutron detection unit consisting of a ZnS:$^6$LiF scintillator with embedded WLS fibers readout by a SiPM. The unit has a sensitive volume of 2.4 x 2.8 x 50 mm$^3$; 12 WLS fibers of diameter 0.25 mm are uniformly distributed over this volume and are coupled to a 1 x 1 mm$^2$ active area SiPM. We report the following performance parameters: neutron detection efficiency $\\sim 65\\,$% at $1.2\\,\\AA$, background count rate $< 10^{-3}$ Hz, gamma-sensitivity with $^{60}$Co source $< 10^{-6}$, dead time $\\sim 20\\,\\mu$s, multi-count ratio $< 1\\,$%. All these parameters were achieved up to the SiPM dark count rate of $\\sim 2\\,$MHz. We consider such detection unit as an elementary building block for realization of one-dimensional multichannel detectors for applications in the neutron scattering experimental technique. The dimensions of the unit and the number of embedded fibers can be varied to meet the specific application requirements. The upp...

  15. Superconducting characteristics of a MgB2 neutron detector fabricated on SiN membrane

    International Nuclear Information System (INIS)

    We report a fabrication process for membrane-structured superconducting MgB2 neutron detectors and measurement of superconducting DC-characteristics. We prepared a MgB2 thin film on a SiN-film-coated Si substrate using multiple-target sputtering system. The 200-nm-thick MgB2 thin film was processed to create meandering lines by e-beam lithography technique, where the line width was 3 μm and the total length reached 6.3 mm. After the front side of the device had been fabricated, the back side of the device was etched with anisotropic Si etching using ethylene diamine pyrocatechol and etching apparatus to increase the sensitivity of the device. The membrane-structured MgB2 device showed good performance of the transition to superconductivity, namely, a T C,onset of 26.24 K, a T C,offset of 26.02 K, ΔT c of 0.22 K, and an RRR of 1.15

  16. Low-Power Miniaturized Helium Dielectric Barrier Discharge Photoionization Detectors for Highly Sensitive Vapor Detection.

    Science.gov (United States)

    Zhu, Hongbo; Zhou, Menglian; Lee, Jiwon; Nidetz, Robert; Kurabayashi, Katsuo; Fan, Xudong

    2016-09-01

    This paper presents the design, fabrication, and characterization of a microhelium dielectric barrier discharge photoionization detector (μHDBD-PID) on chip with dimensions of only ∼15 mm × ∼10 mm × ∼0.7 mm and weight of only ∼0.25 g. It offers low power consumption (4 orders of magnitude), and maintenance-free operation. Furthermore, the μHDBD-PID can be driven with a miniaturized (∼5 cm × ∼2.5 cm × ∼2.5 cm), light (22 g), and low cost (∼$2) power supply with only 1.5 VDC input. The dependence of the μHDBD-PID performance on bias voltage, auxiliary helium flow rate, carrier gas flow rate, and temperature was also systematically investigated. Finally, the μHDBD-PID was employed to detect permanent gases and a sublist of the EPA 8260 standard reagents that include 51 analytes. The μHDBD-PID developed here can have a broad range of applications in portable and microgas chromatography systems for in situ, real-time, and sensitive gas analysis. PMID:27559931

  17. Proton radiation effect on performance of InAs/GaSb complementary barrier infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Soibel, Alexander; Rafol, Sir B.; Khoshakhlagh, Arezou; Nguyen, Jean; Hoglund, Linda; Fisher, Anita M.; Keo, Sam. A.; Ting, David Z.-Y.; Gunapala, Sarath D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, California 91030 (United States)

    2015-12-28

    In this work, we investigated the effect of proton irradiation on the performance of long wavelength infrared InAs/GaSb photodiodes (λ{sub c} = 10.2 μm), based on the complementary barrier infrared detector design. We found that irradiation with 68 MeV protons causes a significant increase of the dark current from j{sub d} = 5 × 10{sup −5} A/cm{sup 2} to j{sub d} = 6 × 10{sup −3} A/cm{sup 2}, at V{sub b} = 0.1 V, T = 80 K and fluence 19.2 × 10{sup 11 }H{sup +}/cm{sup 2}. Analysis of the dark current as a function of temperature and bias showed that the dominant contributor to the dark current in these devices changes from diffusion current to tunneling current after proton irradiation. This change in the dark current mechanism can be attributed to the onset of surface leakage current, generated by trap-assisted tunneling processes in proton displacement damage areas located near the device sidewalls.

  18. Development of Silicon Multi-strip Detector

    Institute of Scientific and Technical Information of China (English)

    TanJilian; JinGenming; WangHongwei; YuanXiaohua; DuanLiming; LiSonglin; LuZiwei; XuHushan; NingBaojun; TianDayu; WangWei; ZhangLu

    2003-01-01

    Position sensitive detector is very important for nuclear physics experiment. There several techniques can be used to fabricate position sensitive detector, for example, Si-surface barrier method, diffusion method, ion implantation and planar process etc. Among all the techniques mentioned above planar process is the best one. We have developed batch of position sensitive detector -- silicon multi-strip detector by using planar process.

  19. Characterization of Si hybrid CMOS detectors for use in the soft X-ray band

    Energy Technology Data Exchange (ETDEWEB)

    Prieskorn, Zachary, E-mail: zpriesko@gmail.com; Griffith, Christopher V.; Bongiorno, Stephen D.; Falcone, Abraham D.; Burrows, David N.

    2013-07-21

    We report on the characterization of four Teledyne Imaging Systems HAWAII Hybrid Si CMOS detectors designed for X-ray detection. Three H1RG detectors were studied along with a specially configured H2RG. Read noise measurements were performed, with the lowest result being 7.1 e{sup −} RMS. Interpixel capacitive crosstalk (IPC) was measured for the three H1RGs and for the H2RG. The H1RGs had IPC upper limits of 4.0–5.5% (up and down pixels) and 8.7–9.7% (left and right pixels), indicating a clear asymmetry. Energy resolution is reported for two X-ray lines, 1.5 and 5.9 keV, at multiple temperatures between 150 and 210 K. The best resolution measured at 5.9 keV was 250 eV (4.2%) at 150 K, with IPC contributing significantly to this measured energy distribution. The H2RG, with a unique configuration designed to decrease the capacitive coupling between ROIC pixels, had an IPC of 1.8±1.0% indicating a dramatic improvement in IPC with no measurable asymmetry. We also measured dark current as a function of temperature for each detector. For the detector with the lowest dark current, at 150 K, we measured a dark current of 0.020±0.001 (e{sup −} s{sup −1} pixel{sup −1}). There is also a consistent break in the fit to the dark current data for each detector. Above 180 K, all the data can be fit by the product of a power law in temperature and an exponential. Below 180 K the dark current decreases more slowly; a shallow power law or constant must be added to each fit, indicating a different form of dark current is dominant in this temperature regime. Dark current figures of merit at 293 K are estimated from the fit for each detector.

  20. Fermi Level Unpinning and Schottky Barrier Modification by Ti,Sc and V Incorporation at NiSi2/Si Interface

    Institute of Scientific and Technical Information of China (English)

    GENG Li; MAGYARI-KOPE Blanka; ZHANG Zhi-Yong; NISHI Yoshio

    2009-01-01

    A new method is proposed to modify the Schottky barrier height (SBH) for nickel silicide/Si contact.Chemical and electrical properties for NiSi2/Si interface with titanium,scandium and vanadium incorporation are investigated by first-principles calculations. The metal/semiconductor interface states within the gap region are greatly decreased,which is related to the diminutions of junction leakage when Ti-eap is experimentally used in nickel silicide/Si contact process.It leads to an unpinning metal/semiconductor interface.The SBH obeys the SchottkyMort theory. Compared to Ti substitution,the SBH for electrons is reduced for scandium and increases for vanadium.

  1. Study of nuclear structure effect on fusion through barrier distribution for the system 28Si+154Sm

    Directory of Open Access Journals (Sweden)

    Kaur Gurpreet

    2015-01-01

    Full Text Available We plan to perform large angle quasi-elastic scattering experiments using a 28Si beam on heavy targets in order to study the nuclear dynamics and structure effects. As a prelude to our first test experiment with a 154Sm target, we study here the existing fusion data for the same system through the barrier distribution.

  2. Measurements of Schottky barrier at the low-k SiOC:H/Cu interface using vacuum ultraviolet photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Pei, D.; Zheng, H.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, S. W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Lin, Y.-H.; Fung, H.-S.; Chen, C.-C. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Nishi, Y. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-12-07

    The band alignment between copper interconnects and their low-k interlayer dielectrics is critical to understanding the fundamental mechanisms involved in electrical leakage in low-k/Cu interconnects. In this work, vacuum-ultraviolet (VUV) photoemission spectroscopy is utilized to determine the potential of the Schottky barrier present at low-k a-SiOC:H/Cu interfaces. By examining the photoemission spectra before and after VUV exposure of a low-k a-SiOC:H (k = 3.3) thin film fabricated by plasma-enhanced chemical-vapor deposition on a polished Cu substrate, it was found that photons with energies of 4.9 eV or greater can deplete accumulated charge in a-SiOC:H films, while VUV photons with energies of 4.7 eV or less, did not have this effect. These critical values were identified to relate the electric potential of the interface barrier between the a-SiOC:H and the Cu layers. Using this method, the Schottky barrier at the low-k a-SiOC:H (k = 3.3)/Cu interface was determined to be 4.8 ± 0.1 eV.

  3. Bent Si monochromator—multi-detector neutron diffractometer installed at B4 super-mirror thermal guide tube in KUR

    Science.gov (United States)

    Achiwa, N.; Kawano, S.; Hino, M.; Mikula, P.; Ono, M.; Fukunaga, T.

    2004-08-01

    A new multi-detector neutron diffractometer has been installed at B4 thermal supermirror neutron guide in KUR, using a new bent Si monochromator developed by Mikula et al. and Ono et al.. Here we report resolutions of powder diffraction patterns by the multi-detector neutron diffractometer, which mainly depend on a radius of sample. Bragg diffraction optics by bent perfect crystal shows improvement of resolution without loss of luminosity and the multi- detector on the same 2 θ arm can gain the intensity without loosing resolution.

  4. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

    Science.gov (United States)

    Karthikeya Sharma, T

    2015-11-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied. PMID:26644918

  5. Digital Processing and Segmentation of Breast Microcalcifications Images Obtained by a Si Microstrips Detector: Preliminary Results

    Science.gov (United States)

    Díaz, Claudia. C.; Angulo, Abril A.

    2007-02-01

    We present the preliminary results of digital processing and segmentation of breast microcalcifications images. They were obtained using a Bede X ray tube with Cu anode, which was fixed at 20 kV and 1 mA. Different biopsies were scanned using a 128 Si microstrips detector. Total scanning resulted in a data matrix, which corresponded with the image of each biopsy. We manipulated the contrast of the images using histograms and filters in the frequency domain in Matlab. Then we intended to investigate about different contour models for the segmentation of microcalcifications boundaries, which were based on the contrast and shape of the image. These algorithms could be applied to mammographic images, which may be obtained by digital mammography or digitizing conventional mammograms.

  6. Study of commercial Si-PIN photodiode as an x-ray detector

    International Nuclear Information System (INIS)

    Two commercial Si-PIN photodiode were evaluated as a low cost X-ray detector in conjunction with forward biased FET preamplifiers. Evaluation was done at room temperature and at a temperature of about -10degC using X-ray spectroscopy amplifier with 241Am radio active source. The results shows 700 eV full width at half maximum for 241Am γ-ray (59.5 keV) with S5821-02 from Hamamatsu Photonics at low temperature and 800 eV with S1722-02 at the same conditions. The S1722-02 photodiode showed almost flat response up to 20 keV X-ray energy. The improvement of photodiode and FET cooling system and proper selection of FET will be expected to show better resolution. (author)

  7. Development and Performance Evaluations of HfO2-Si and Rare Earth-Si Based Environmental Barrier Bond Coat Systems for SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming

    2014-01-01

    Ceramic environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft propulsion systems because of their ability to significantly increase engine operating temperatures, improve component durability, reduce engine weight and cooling requirements. Advanced EBC systems for SiCSiC CMC turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant material development challenges for the high temperature CMC components is to develop prime-reliant, high strength and high temperature capable environmental barrier coating bond coat systems, since the current silicon bond coat cannot meet the advanced EBC-CMC temperature and stability requirements. In this paper, advanced NASA HfO2-Si based EBC bond coat systems for SiCSiC CMC combustor and turbine airfoil applications are investigated. The coating design approach and stability requirements are specifically emphasized, with the development and implementation focusing on Plasma Sprayed (PS) and Electron Beam-Physic Vapor Deposited (EB-PVD) coating systems and the composition optimizations. High temperature properties of the HfO2-Si based bond coat systems, including the strength, fracture toughness, creep resistance, and oxidation resistance were evaluated in the temperature range of 1200 to 1500 C. Thermal gradient heat flux low cycle fatigue and furnace cyclic oxidation durability tests were also performed at temperatures up to 1500 C. The coating strength improvements, degradation and failure modes of the environmental barrier coating bond coat systems on SiCSiC CMCs tested in simulated stress-environment interactions are briefly discussed and supported by modeling. The performance enhancements of the HfO2-Si bond coat systems with rare earth element dopants and rare earth-silicon based bond coats are also highlighted. The advanced bond coat systems, when

  8. Electrical Characteristics of Co/n-Si Schottky Barrier Diodes Using I-V and C-V Measurements

    Institute of Scientific and Technical Information of China (English)

    G.Gfüler; (O).Güllü; (S).Karata(s); (O).F.Bakkalo(g)lu

    2009-01-01

    Electrical characteristics of Co/n-Si Schottky barrier diodes are analysed by current-voltage (I- V) and capacitancevoltage (C-V) techniques at room temperature.The electronic parameters such as ideality factor,barrier height and average series resistance are determined.The barrier height 0.76 eV obtained from the C-V measurements is higher than that of the value 0.70 eV obtained from the I-V measurements.The series resistance Rs and the ideality factor n are determined from the d ln( I ) / dV plot and are found to be 193.62Ω and 1.34,respectively.The barrier height and the Rs value are calculated from the H(I) - I plot and are found to be 0.71 eV and 205.95Ω.Furthermore,the energy distribution of the interface state density is determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height.The interface state density Nss ranges from 6.484×1011 cm-2eV-1 in (Ec-0.446) eV to 2.801×1010 cm-2eV-1 in (Ec-0.631) eV,of the Co/n-Si Schottky barrier diode.The results show the presence of a thin interracial layer between the metal and the semiconductor.

  9. Investigation of current transport parameters of Ti/4H-SiC MPS diode with inhomogeneous barrier

    Institute of Scientific and Technical Information of China (English)

    Song Qing-Wen; Zhang Yu-Ming; Zhang Yi-Men; Chen Feng-Ping; Tang xiao-Yan

    2011-01-01

    The current transport parameters of 4H-SiC merged PiN Schottky (MPS) diode are investigated in a temperature range of 300-520 K. Evaluation of the experimental current-voltage (Ⅰ-Ⅴ) data reveals the decrease in Schottky barrier height φb but an increase in ideality factor n, with temperature decreasing, which suggests the presence of an inhomogeneous Schottky barrier. The current transport behaviours are analysed in detail using the Tung's model and the effective area of the low barrier patches is extracted. It is found that small low barrier patches, making only 4.3% of the total contact, may significantly influence the device electrical characteristics due to the fact that a barrier height of 0.968 eV is much lower than the average barrier height 1.39 eV. This shows that ion implantation in the Schottky contact region of MPS structure may result in a poor Ti/4H-SiC interface quality. In addition, the temperature dependence of the specific on-resistance (Ron-sp), T2.14, is determined between 300 K and 520 K, which is similar to that predicted by a reduction in electron mobility.

  10. Characterization of Si Hybrid CMOS Detectors for use in the Soft X-ray Band

    CERN Document Server

    Prieskorn, Zachary; Bongiorno, Stephen D; Falcone, Abraham D; Burrows, David N

    2013-01-01

    We report on the characterization of four Teledyne Imaging Systems HAWAII Hybrid Si CMOS detectors designed for X-ray detection. Three H1RG detectors were studied along with a specially configured H2RG. Read noise measurements were performed, with the lowest result being 7.1 e- RMS. Interpixel capacitive crosstalk (IPC) was measured for the three H1RGs and for the H2RG. The H1RGs had IPC upper limits of 4.0 - 5.5 % (up & down pixels) and 8.7 - 9.7 % (left & right pixels), indicating a clear asymmetry. Energy resolution is reported for two X-ray lines, 1.5 & 5.9 keV, at multiple temperatures between 150 - 210 K. The best resolution measured at 5.9 keV was 250 eV (4.2 %) at 150 K, with IPC contributing significantly to this measured energy distribution. The H2RG, with a unique configuration designed to decrease the capacitive coupling between ROIC pixels, had an IPC of 1.8 +/- 1.0 % indicating a dramatic improvement in IPC with no measurable asymmetry. We also measured dark current as a function of ...

  11. SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array

    Science.gov (United States)

    Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore

    2014-07-01

    The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.

  12. NASA's Advanced Environmental Barrier Coatings Development for SiC/SiC Ceramic Matrix Composites: Understanding Calcium Magnesium Alumino-Silicate (CMAS) Degradations and Resistance

    Science.gov (United States)

    Zhu, Dongming

    2014-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is essential to the viability and reliability of the envisioned CMC engine component applications, ensuring integrated EBC-CMC system durability and designs are achievable for successful applications of the game-changing component technologies and lifing methodologies.This paper will emphasize recent NASA environmental barrier coating developments for SiCSiC turbine airfoil components, utilizing advanced coating compositions, state-of-the-art processing methods, and combined mechanical and environment testing and durability evaluations. The coating-CMC degradations in the engine fatigue-creep and operating environments are particularly complex; one of the important coating development aspects is to better understand engine environmental interactions and coating life debits, and we have particularly addressed the effect of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the durability of the environmental barrier coating systems, and how the temperature capability, stability and cyclic life of the candidate rare earth oxide and silicate coating systems will be impacted in the presence of the CMAS at high temperatures and under simulated heat flux conditions. Advanced environmental barrier coating systems, including HfO2-Si with rare earth dopant based bond coat systems, will be discussed for the performance improvements to achieve better temperature capability and CMAS resistance for future engine operating conditions.

  13. A self-biased neutron detector based on an SiC semiconductor for a harsh environment.

    Science.gov (United States)

    Ha, Jang Ho; Kang, Sang Mook; Park, Se Hwan; Kim, Han Soo; Lee, Nam Ho; Song, Tae-Yung

    2009-01-01

    Neutron detector based on radiation-hard semiconductor materials like SiC, diamond and AlN has recently emerged as an attractive device for an in-core reactor neutron flux monitoring, a spent fuel characterization, and a home land security application. For the purpose of field measurement activity, a radiation detector having a low-power consumption, a mechanical stability and a radiation hardness is required. Our research was focused on the development of a radiation-resistive neutron semiconductor detector based on a wide band-gap SiC semiconductor. And also it will be operated at a zero-biased voltage using a strong internal electric field. The charge collection efficiency (CCE) was over 80% when the biased voltage was zero. When the biased voltage was applied above 20V, the charge collection efficiency reached 100%. PMID:19362006

  14. Resistance switching memory characteristics of CaF2/Si/CaF2 resonant-tunneling quantum-well heterostructures sandwiched by nanocrystalline Si secondary barrier layers

    Science.gov (United States)

    Kuwata, Yuya; Suda, Keita; Watanabe, Masahiro

    2016-07-01

    A novel resistance switching memory using CaF2/Si/CaF2 resonant-tunneling quantum well heterostructures sandwiched by nanocrystalline Si (nc-Si) as secondary barrier layers has been proposed and the room temperature current–voltage characteristics of the basic resistance switching memory operation have been demonstrated. A resistance switching voltage of 1.0 V, a peak current density of approximately 42 kA/cm2, and an ON/OFF ratio of 2.8 were observed. In particular, more than 28000 write-read-erase cyclic memory operations have been demonstrated by applying pulsed input voltage sequences, which suggests better endurance than the device using a CaF2/CdF2/CaF2 heterostructure.

  15. Detection of fast neutrons from D-T nuclear reaction using a 4H-SiC radiation detector

    Science.gov (United States)

    Zatko, Bohumir; Sagatova, Andrea; Sedlackova, Katarina; Necas, Vladimir; Dubecky, Frantisek; Solar, Michael; Granja, Carlos

    2016-09-01

    The particle detector based on a high purity epitaxial layer of 4H-SiC exhibits promising properties in detection of various types of ionizing radiation. Due to the wide band gap of 4H-SiC semiconductor material, the detector can reliably operate at room and also elevated temperatures. In this work we focused on detection of fast neutrons generated the by D-T (deuterium-tritium) nuclear reaction. The epitaxial layer with a thickness of 105 μm was used as a detection part. A circular Schottky contact of a Au/Ni double layer was evaporated on both sides of the detector material. The detector structure was characterized by current-voltage and capacitance-voltage measurements, at first. The results show very low current density (contained in the conversion layer have a high probability of interaction with neutrons through elastic scattering. Secondary generated protons flying to the detector can be easily detected. The detection properties of detectors with and without the HDPE conversion layer were compared.

  16. Development of Ion-Implanted Si-PIN Semiconductor Radiation Detector%离子注入型Si-PIN半导体探测器的研制

    Institute of Scientific and Technical Information of China (English)

    宋明东; 卜忍安

    2011-01-01

    本文系统地介绍了Si-PIN探测器对带电粒子、中子、射线的探测原理.针对灵敏面积为φ30mm×420μm的Si-PIN探测器,详细地介绍了设计方法和工艺流程,并指出了影响探测器性能的关键工艺.采用离子注入和平面工艺不仅能够降低漏电流,提高探测器的能量分辨率,而且使得探测器对高温环境和真空都很稳定.最后初步介绍了探测器的电特性(I-V特性,C-V特性)的变化趋势,以及探测特性参数的测量方法.%The principle of Si-PIN semiconductor detector detecting charged particle, neutron and radiation are introduced systematically in this article. The design procedures and technology process of the detector whose sensitive area is φ30 mm X 420 um are introduced. The key technologies which affect performance of the detector are also presented. The ion-implanted planar technology could reduce leakage current and enhance resolution of the detector as well as improves stability of the detector in high-temperature and vacuum environment. At last, I-V and C-V characteristics curves as well as detecting characteristic parameters are also introduced preliminarily.

  17. Thermal stability of atomic layer deposited Ru layer on Si and TaN/Si for barrier application of Cu interconnection.

    Science.gov (United States)

    Shin, Dong Chan; Kim, Moo Ryul; Lee, Jong Ho; Choi, Bum Ho; Lee, Hong Kee

    2012-07-01

    The thermal stability of thin Ru single layer and Ru/TaN bilayers grown on bare Si by plasma enhanced atomic layer deposition (PEALD) have been studied with Cu/Ru, Cu/Ru/TaN structures as a function of annealing temperature. To investigate the characteristics as a copper diffusion barrier, a 50 nm thick Cu film was sputtered on Ru and Ru/TaN layers and each samples subjected to thermal annealing under N2 ambient with varied temperature 300, 400, and 500 degrees C, respectively. It was found that the single 5 nm thick ALD Ru layer acted as an effective Cu diffusion barrier up to 400 degrees C. On the other hand ALD Ru (5 nm)/TaN (3.2 nm) showed the improved diffusion barrier characteristics even though the annealing temperature increased up to 500 degrees C. Based on the experimental results, the failure mechanism of diffusion barrier would be related to the crystallization of amorphous Ru thin film as temperature raised which implies the crystallized Ru grain boundary served as the diffusion path of Cu atoms. The combination of ALD Ru incorporated with TaN layer would be a promising barrier structure in Cu metallization.

  18. In Situ XPS Chemical Analysis of MnSiO3 Copper Diffusion Barrier Layer Formation and Simultaneous Fabrication of Metal Oxide Semiconductor Electrical Test MOS Structures.

    Science.gov (United States)

    Byrne, Conor; Brennan, Barry; McCoy, Anthony P; Bogan, Justin; Brady, Anita; Hughes, Greg

    2016-02-01

    Copper/SiO2/Si metal-oxide-semiconductor (MOS) devices both with and without a MnSiO3 barrier layer at the Cu/SiO2 interface have been fabricated in an ultrahigh vacuum X-ray photoelectron spectroscopy (XPS) system, which allows interface chemical characterization of the barrier formation process to be directly correlated with electrical testing of barrier layer effectiveness. Capacitance voltage (CV) analysis, before and after tube furnace anneals of the fabricated MOS structures showed that the presence of the MnSiO3 barrier layer significantly improved electric stability of the device structures. Evidence of improved adhesion of the deposited copper layer to the MnSiO3 surface compared to the clean SiO2 surface was apparent both from tape tests and while probing the samples during electrical testing. Secondary ion mass spectroscopy (SIMS) depth profiling measurements of the MOS test structures reveal distinct differences of copper diffusion into the SiO2 dielectric layers following the thermal anneal depending on the presence of the MnSiO3 barrier layer. PMID:26732185

  19. A Study of the Impact of High Cross Section ILC Processes on the SiD Detector Design

    CERN Document Server

    Barklow, Timothy; Milke, Christopher; Schumm, Bruce; Schütz, Anne; Stanitzki, Marcel; Strube, Jan

    2016-01-01

    The SiD concept is one of two proposed detectors to be mounted at the interaction region of the International Linear Collider (ILC). A substantial ILC background arises from low transverse momentum $\\mathrm{e}^{+}\\mathrm{e}^{-}$ pairs created by the interaction of the colliding beams' electromagnetic fields. In order to provide hermeticity and sensitivity to beam targeting parameters, a forward Beamline Calorimeter (BeamCal) is being designed that will provide coverage down to 5 mrad from the outgoing beam trajectory, and intercept the majority of this pair background. Using the SiD simulation framework, the effect of this pair background on the SiD detector components, especially the vertex detector (VXD) and forward electromagnetic calorimeter (FCAL), is explored. In the case of the FCAL, backgrounds from Bhabha and two-photon processes are also considered. The consequence of several variants of the BeamCal geometry and ILC interaction region configuration are considered for both the vertex detector and Bea...

  20. Large barrier, highly uniform and reproducible Ni-Si/4H-SiC forward Schottky diode characteristics: testing the limits of Tung's model

    International Nuclear Information System (INIS)

    We report highly ideal (n 14–1016 cm−3, apart from a slight decrease consistent with image force lowering. This remarkable uniformity was achieved by careful optimization of the annealing of the Schottky interface to minimize non-idealities that could lead to inhomogeneity. Tung's barrier inhomogeneity model was used to quantify the level of inhomogeneity in the optimized annealed diodes. The estimated ‘bulk’ barrier height (1.75 eV) was consistent with the Shockley–Mott limit for the Ni–Si/4H-SiC interface, implying an unpinned Fermi level. But the model was not useful to explain the poor ideality in unoptimized, as-deposited Schottky contacts (n = 1.6 − 2.5). We show analytically and numerically that only idealities n < 1.21 can be explained using Tung's model, irrespective of material system, indicating that the barrier height inhomogeneity is not the only cause of poor ideality in Schottky diodes. For explaining this highly non-ideal behaviour, other factors (e.g. interface traps, morphological defects, extrinsic impurities, etc) need to be considered. (paper)

  1. Experimental characterization and Monte Carlo simulation of Si(Li) detector efficiency by radioactive sources and PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Mesradi, M. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France); Elanique, A. [Departement de Physique, FS/BP 8106, Universite Ibn Zohr, Agadir, Maroc (Morocco); Nourreddine, A. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)], E-mail: abdelmjid.nourreddine@ires.in2p3.fr; Pape, A.; Raiser, D.; Sellam, A. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)

    2008-06-15

    This work relates to the study and characterization of the response function of an X-ray spectrometry system. The intrinsic efficiency of a Si(Li) detector has been simulated with the Monte Carlo codes MCNP and GEANT4 in the photon energy range of 2.6-59.5 keV. After finding it necessary to take a radiograph of the detector inside its cryostat to learn the correct dimensions, agreement within 10% between the simulations and experimental measurements with several point-like sources and PIXE results was obtained.

  2. Study of barrier inhomogeneities using I–V–T characteristics of Mo/4H–SiC Schottky diode

    International Nuclear Information System (INIS)

    In the present work we investigate the forward current–voltage (I–V) characteristics, over a wide temperature range 298–498 K, of Mo/4H–SiC Schottky diode for which aluminum ion implantation was used to create the high resistivity layer forming the guard ring. The (I–V) analysis based on Thermionic Emission (TE) theory shows a decrease of the barrier height ϕB and an increase of the ideality factor n when the temperature decreases. These anomalies are mainly due to the barrier height inhomogeneities at the metal/semiconductor interface as we get a Gaussian distribution of the barrier heights when we plot the apparent barrier height ϕap versus q/2kT. The mean barrier height and the standard deviation obtained values are ϕ¯B0=1.160 eV and σ0=88.049 mV, respectively. However, by means of the modified Richardson plot Ln(Is/T2)−(q2σ02/2k2T2) versus q/kT, the mean barrier height and the Richardson constant values obtained are ϕ¯B0=1.139 eV and A*=129.425 A/cm2 K2, respectively. The latter value of ϕ¯B0 matches very well with the mean barrier height obtained from the plot of ϕap versus q/2kT. The Richardson constant is much closer to the theoretical value of 146 A/cm2 K2. The series resistance Rs is also estimated from the forward current–voltage characteristics of Mo/4H–SiC Schottky contact. This parameter shows strong temperature dependence. The T0 effect is validated for the 298–498 K temperature range for the used Schottky diode and provides a clear evidence for the barrier inhomogeneity at the Mo/4H–SiC interface. Finally, we note the impact of the implantation process as well as the choice of the used ion on the characterized parameters of the Schottky contact

  3. Energy dispersive X-ray fluorescence from useless tyres samples with a Si PIN detector

    International Nuclear Information System (INIS)

    The concentration of Zn from discard tyre samples is of environmental interest, since on its production are used S for the rubber vulcanization process, and Zn O as reaction catalyze. The useless tyres are been used for asphalt pave, burn in cement industry and thermoelectric power plant and in erosion control of agriculture areas. Analyses of these samples requires frequently chemical digestion that is expensive and take a long time. Trying to eliminate these limitations, the objective of this work was use Energy Dispersive X Ray Fluorescence technique (EDXRF) with a portable system as the technique is multi elementary and needs a minimum sample preparation. Five useless tyres samples were grind in a knife mill and after this in a cryogenic mill, and analyzed in pellets form, using a X ray mini tube (Ag target, Mo lter, 25 kV/20 A) for 200 s and a Si-PIN semiconductor detector coupled to a multichannel analyzer. Were obtained Zn concentrations in the range of 40.6 to 44.2 g g1, representing nearly 0.4. (author)

  4. Model and analysis of drain induced barrier lowering effect for 4H-SiC metal semiconductor field effct transistor

    Institute of Scientific and Technical Information of China (English)

    Cao Quan-Jun; Zhang Yi-Men; Jia Li-xin

    2009-01-01

    Based on an analytical solution of the two-dimensional Poisson equation in the subthreshold region. this paper investigates the behavior of DIBL(drain induced barrier lowering)effect for short channel 4H-SiC metal semiconductor field effect transistors(MESFETs). An accurate analytical model of threshold voltage shift for the asymmetric short channel 4H-SiC MESFET is presented and thus verified. According to the presented model. it analyses the threshold voltage for short channel device on the L/a(channel length/channel depth)ratio, drain applied voltage VDS and channel doping concentration ND, thus providing a good basis for the design and modelling of short channel 4H-SiC MESFETs device.

  5. Preparation and properties of SiCN diffusion barrier layer for Cu interconnect in ULSI

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ji-cheng; SHI Zhi-jie; ZHENG Xu-qiang

    2009-01-01

    SiCN thin films and Cu/SiCN/Si structures were fabricated by magnetron sputtering. And some samples underwent the rapid thermal annealing(RTA) processing. The thin-film surface morphology, crystal structure and electronic properties were characterized by atomic force microscopy(AFM), X-ray diffractometry(XRD), Fourier transform infrared transmission(FTIR) and four-point probe(FPP) analyses. The results reveal the formation of complex networks among the three elements, Si, C and N, and the existence of different chemical bonds in the SiCN films, such as Si-C, Si-N, C-N and C=N. The as-deposited SiCN thin films are amorphous in the Cu/SiCN/Si structures and have good thermal stability, and the SiCN thin films are still able to prevent the diffusion reaction between Cu and Si interface after RTA processing at 600 ℃ for 5 min.

  6. Strained-Si modulation doped field effect transistors as detectors of terahertz and sub-terahertz radiation

    Science.gov (United States)

    Rumyantsev, S. L.; Fobelets, K.; Veksler, D.; Hackbarth, T.; Shur, M. S.

    2008-10-01

    Strained-Si modulation doped field effect transistors have been studied as detectors of 0.2 THz and 1.6 THz electromagnetic radiation at room temperature. The difference in the gate voltage dependences for 0.2 THz and 1.6 THz radiation and spatial pattern of the transistor response to focused 1.6 THz radiation confirms that the mechanism of detection is linked to the excitations of the two-dimensional electrons in the device channel.

  7. Comparative Study of SiO2, Al2O3, and BeO Ultrathin Interfacial Barrier Layers in Si Metal-Oxide-Semiconductor Devices

    Directory of Open Access Journals (Sweden)

    J. H. Yum

    2012-01-01

    Full Text Available In a previous study, we have demonstrated that beryllium oxide (BeO film grown by atomic layer deposition (ALD on Si and III-V MOS devices has excellent electrical and physical characteristics. In this paper, we compare the electrical characteristics of inserting an ultrathin interfacial barrier layer such as SiO2, Al2O3, or BeO between the HfO2 gate dielectric and Si substrate in metal oxide semiconductor capacitors (MOSCAPs and n-channel inversion type metal oxide semiconductor field effect transistors (MOSFETs. Si MOSCAPs and MOSFETs with a BeO/HfO2 gate stack exhibited high performance and reliability characteristics, including a 34% improvement in drive current, slightly better reduction in subthreshold swing, 42% increase in effective electron mobility at an electric field of 1 MV/cm, slightly low equivalent oxide thickness, less stress-induced flat-band voltage shift, less stress induced leakage current, and less interface charge.

  8. RBS using {sup 28}Si beams

    Energy Technology Data Exchange (ETDEWEB)

    Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia); Mitchell, I.V. [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1996-12-31

    Measurements of RBS using {sup 28}Si beams have been made to evaluate the enhancement of sensitivity that should obtain from kinematic suppression of silicon substrate scattering. Two detection methods were tried. Aside from a surface barrier detector, a magnetic spectrometer, instrumented with a multi-electrode gas focal plane detector, was used to indicate the resolution attainable with low energy {sup 28}Si ions. The results confirm that kinematically suppressed RBS does provide greatly improved sensitivity. 5 refs., 2 figs.

  9. Development of novel on-chip, customer-design spiral biasing adaptor on for Si drift detectors and detector arrays for X-ray and nuclear physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng, E-mail: lizheng@xtu.edu.cn [School of Materials, Optoelectronics and Physics, Xiangtan University, Xiangtan, Hunan 411105 (China); Chen, Wei [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2014-11-21

    A novel on-chip, customer-design spiral biasing adaptor (SBA) has been developed. A single SBA is used for biasing a Si drift detector (SDD) and SDD array. The use of an SBA reduces the biasing current. This paper shows the calculation of the geometry of an SBA and an SDD to get the best drift field in the SDD and SDD array. Prototype SBAs have been fabricated to verify the concept. Electrical measurements on these SBAs are in agreement with the expectations. The new SDD array with an SBA can be used for X-ray detection and in nuclear physics experiments.

  10. K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors

    International Nuclear Information System (INIS)

    We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images. (paper)

  11. Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

    Directory of Open Access Journals (Sweden)

    Jakubek J.

    2012-10-01

    Full Text Available We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The new prototype uses a larger SiPM array to cover the entire top face of the tile. This paper details the comparative performance of the two prototype designs. A deuterium-tritium (DT fast-neutron source was used to compare the relative light collection efficiency of the two designs. A collimated UV light source was scanned across the detector face to map the uniformity. The new prototype was found to have 9.5 times better light collection efficiency over the original design. Both prototypes exhibit spatial non-uniformity in their response. Methods of correcting this non-uniformity are discussed.

  12. A feasibility study to track cosmic muons using a detector with SiPM devices based on amplitude discrimination

    CERN Document Server

    Stanca, D; Brancus, I; Mitrica, B; Balaceanu, A; Cautisanu, B; Gherghel-Lascu, A; Haungs, A; Mathes, H -J; Rebel, H; Saftoiu, A; Sima, O; Mosu, T

    2016-01-01

    The possibility to build a SiPM-readout muon detector (SiRO), using plastic scintillators with optical fibers as sensitive volume and readout by SiPM photo-diodes, is investigated. SiRO shall be used for tracking cosmic muons based on amplitude discrimination. The detector concept foresees a stack of 6 active layers, grouped in 3 sandwiches for determining the muon trajectories through 3 planes. After investigating the characteristics of the photodiodes, tests have been performed using two detection modules, each being composed from a plastic scintillator sheet, $100 \\times 25 \\times 1\\,$cm$^{3}$, with 12 parallel, equidistant ditches; each ditch filled with an optical fiber of $1.5\\,$mm thickness and always two fibers connected to form a channel. The attenuation of the light response along the optical fiber and across the channels have been tested. The measurements of the incident muons based on the input amplitude discrimination indicate that this procedure is not efficient and therefore not sufficient, as ...

  13. K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors

    Science.gov (United States)

    Cassol, F.; Portal, L.; Graber-Bolis, J.; Perez-Ponce, H.; Dupont, M.; Kronland, C.; Boursier, Y.; Blanc, N.; Bompard, F.; Boudet, N.; Buton, C.; Clémens, J. C.; Dawiec, A.; Debarbieux, F.; Delpierre, P.; Hustache, S.; Vigeolas, E.; Morel, C.

    2015-07-01

    We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images.

  14. High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films.

    Science.gov (United States)

    Verma, V B; Korzh, B; Bussières, F; Horansky, R D; Dyer, S D; Lita, A E; Vayshenker, I; Marsili, F; Shaw, M D; Zbinden, H; Mirin, R P; Nam, S W

    2015-12-28

    We report on MoSi SNSPDs which achieved high system detection efficiency (87.1 ± 0.5% at 1542 nm) at 0.7 K and we demonstrate that these detectors can also be operated with saturated internal efficiency at a temperature of 2.3 K in a Gifford-McMahon cryocooler. We measured a minimum system jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.3 ± 0.1%. The performance of MoSi SNSPDs at 2.3 K is similar to the performance of WSi SNSPDs at < 1 K. The higher operating temperature of MoSi SNSPDs makes these devices promising for widespread use due to the simpler and less expensive cryogenics required for their operation.

  15. Effects of mid-gap defects and barrier interface reactions on tunneling behaviors of ZnO-i-Si heterojunctions

    Science.gov (United States)

    Chang, Chun-Fu; Wadekar, Paritosh V.; Hsieh, Wan-Chen; Lin, Wen-Yen; Wang, Yu-Sheng; Wang, Jun-Hau; Lin, Jyun-Jie; Huang, Hui-Chun; Chang, Ching-Wen; Tu, Li-Wei; Liao, Chih-Hsiung; Liao, Hua-Hsien; Ho, New-Jin; Seo, Hye-Won; Chen, Quark Y.; Chu, Wei-Kan

    2016-07-01

    Low-leakage pin diodes based on ZnO-i-Si are realized by redox reaction of aluminum with the native oxide SiOx into AlOx and by proper selection of annealing conditions. The main sources of electric leakage was found to arise from charge carrier tunneling via mid-gap states in the semiconductors or lowered tunneling barriers. Less mid-gap states in n-ZnO and high tunneling barrier of the i-layer are key to lowering the leakage. Proper post-annealing of pin diodes effectively heal the mid-gap defects, while maintaining the integrity of the tunneling layers, thus lowering the leakage currents to reach a rectification ratio of 2400, surpassing most similarly benchmarked devices reported in literature. Excessive annealing causes some part of the i-layer to transform into to ZnAl2O4 and Al:ZnO. High Al-doping and lowered potential barrier provided by ZnAl2O4 are responsible for high leakage currents in devices so fabricated.

  16. POCl3 diffusion with in-situ SiO2 barrier for selective emitter multicrystalline solar grade silicon solar cells

    OpenAIRE

    Urrejola, Elias; Kristian, Peter; Soiland, Anne-Karin; Enebakk, Erik

    2009-01-01

    We present an innovative process for the formation of a selective emitter by using an advanced phosphorous glass as a barrier layer against subsequent diffusion. The advanced barrier glass was achieved by the formation of a standard phosphorous glass treated with additional thermal oxidation immediately after deposition in the same process tube. The resistant layer is used as a barrier for the second diffusion after selective opening of the finger contact areas by screen printing of a SiO2 et...

  17. Reliable determination of the Cu/n-Si Schottky barrier height by using in-device hot-electron spectroscopy

    International Nuclear Information System (INIS)

    We show the operation of a Cu/Al2O3/Cu/n-Si hot-electron transistor for the straightforward determination of a metal/semiconductor energy barrier height even at temperatures below carrier-freeze out in the semiconductor. The hot-electron spectroscopy measurements return a fairly temperature independent value for the Cu/n-Si barrier of 0.66 ± 0.04 eV at temperatures below 180 K, in substantial accordance with mainstream methods based on complex fittings of either current-voltage (I-V) and capacitance-voltage (C-V) measurements. The Cu/n-Si hot-electron transistors exhibit an OFF current of ∼2 × 10−13 A, an ON/OFF ratio of ∼105, and an equivalent subthreshold swing of ∼96 mV/dec at low temperatures, which are suitable values for potential high frequency devices

  18. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

    Directory of Open Access Journals (Sweden)

    T. Karthikeya Sharma

    2015-11-01

    Full Text Available Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE. This paper investigates the effects of using argon (Ar gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied.

  19. Radiation damage effects by electrons, protons, and neutrons in Si/Li/ detectors.

    Science.gov (United States)

    Liu, Y. M.; Coleman, J. A.

    1972-01-01

    The degradation in performance of lithium-compensated silicon nuclear particle detectors induced by irradiation at room temperature with 0.6-MeV and 1.5-MeV electrons, 1.9-MeV protons, and fast neutrons from a plutonium-beryllium source has been investigated. With increasing fluence, the irradiations produced an increase of detector leakage current, noise, capacitance, and a degradation in the performance of the detector as a charged-particle energy spectrometer. Following the irradiations, annealing effects were observed when the detectors were reverse-biased at their recommended operating voltages. Upon removal of bias, a continuous degradation of detector performance characteristics occurred. Detectors which had been damaged by electrons and protons exhibited a stabilization in their characteristics within two weeks after irradiation, whereas detectors damaged by neutrons had a continuous degradation of performance over a period of several months.

  20. Growth and properties of LPCVD W-Si-N barrier layers

    NARCIS (Netherlands)

    Bystrova, S.; Holleman, J.; Woerlee, P.H.

    2001-01-01

    In this work the low-temperature low pressure chemical vapour deposition (LPCVD) of W�Si�N compounds in the WF6�NF3�SiH4�Ar system is presented. Layers were deposited on oxidised Si-wafers at 385 and 250

  1. Rectifying barrier at GaN/SiC hetero-junction studied with positron annihilation spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hu Yi-Fan; Beling C D

    2005-01-01

    Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This "rectifying" effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit (VEPF) analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.

  2. Effect of temperature on the carrier transport property of 4H-SiC based Schottky barrier diode

    Directory of Open Access Journals (Sweden)

    TONG Wulin

    2015-08-01

    Full Text Available In this paper,the current-voltage (I-V measurement under different temperatures was carried out on the 4H-SiC Schottky barrier diode (SBD purchased from Cree Inc.The carrier transport mechanism and the temperature effect of SBD were investigated through the theoretical simulation based on the experimental data.The Schottky barrier height is decreased and leakage current is increased sharply for SBD when the temperatures are increased.The SBD forward bias obeys the hot electron emission mechanism.Taking the image force correction and tunneling effect into consideration,the high leakage current under reverse bias can be reasonably explained and is good agreement with the experiment results.

  3. Temperature dependence of the inhomogeneous parameters of the Mo/4H–SiC Schottky barrier diodes

    Science.gov (United States)

    Latreche, A.; Ouennoughi, Z.; Weiss, R.

    2016-08-01

    The inhomogeneous parameters of Mo/4H–SiC Schottky barrier diodes were determined from current–voltage (I–V) characteristics in the temperature range of 303–498 K by using a general approach for the real Schottky diode. In this approach the total series resistances is divided into two resistances; the first one (R P) is the sum of the series resistances (r) of the particular diodes connected in parallel and the second is the common resistance (R C) to all particular diodes. The mean barrier height (\\bar{φ }) and the standard deviation (σ) decrease linearly with decreasing temperature and they are between the values for the diodes with the two limiting cases; no current spreading and full current spreading. The series resistance R C increases, while the series resistance R P slightly decreases with decreasing temperature.

  4. Diffusion barrier properties of atomic-layer-deposited iridium thin films on Cu/Ir/Si structures

    International Nuclear Information System (INIS)

    We investigated the diffusion barrier properties of an atomic-layer-deposited 12-nm-thick iridium (Ir) thin film as functions of the thermal treatment temperature. Up to a temperature of 500 .deg. C, the Ir thin film maintained its initial configuration, preventing the penetration of the Cu layer into Si through the Ir layer. The thermal stability of the Ir layer up to 500 .deg. C was confirmed by using high resolution transmission electron microscopy, Auger electron microscopy, and X-ray diffraction. In contrast, when the Ir layer was thermally annealed at 600 .deg. C, copper silicide was formed, and interdiffusion of Cu and Ir was observed.

  5. Environmental and Mechanical Stability of Environmental Barrier Coated SA Tyrannohex SiC Composites Under Simulated Turbine Engine Environments

    Science.gov (United States)

    Zhu, Dongming; Halbig, Michael Charles; Sing, Mrityunjay

    2014-01-01

    The environmental stability and thermal gradient cyclic durability performance of SA Tyrannohex composites were investigated for turbine engine component applications. The work has been focused on investigating the combustion rig recession, cyclic thermal stress resistance and thermomechanical low cycle fatigue of uncoated and environmental barrier coated Tyrannohex SiC SA composites in simulated turbine engine combustion water vapor, thermal gradients, and mechanical loading conditions. Flexural strength degradations have been evaluated, and the upper limits of operating temperature conditions for the SA composite material systems are discussed based on the experimental results.

  6. Time resolution of time-of-flight detector based on multiple scintillation counters readout by SiPMs

    CERN Document Server

    Cattaneo, P W; Gatti, F; Nishimura, M; Ootani, W; Rossella, M; Shirabe, S; Uchiyama, Y

    2015-01-01

    A new timing detector measuring ~50 MeV/c positrons is under development for the MEG II experiment, aiming at a time resolution $\\sigma_t \\sim 30~\\mathrm{ps}$. The resolution is expected to be achieved by measuring each positron time with multiple counters made of plastic scintillator readout by silicon photomultipliers (SiPMs). The purpose of this work is to demonstrate the time resolution for ~50 MeV/c positrons using prototype counters. Counters with dimensions of $90\\times 40\\times 5~\\mathrm{mm}^3$ readout by three SiPMs at each end were build with SiPMs from Hamamatsu Photonics and AdvanSiD and tested in a positron beam at the DA$\\Phi$NE Beam Test Facility. It was found that the time resolution improves nearly as the square root of the number of counter hits. A time resolution $\\sigma_t=26.2\\pm1.3~\\mathrm{ps}$ was obtained with eight counters with Hamamatsu SiPMs. These results suggest that the design resolution is achievable in the MEG II experiment.

  7. Time resolution of time-of-flight detector based on multiple scintillation counters readout by SiPMs

    Science.gov (United States)

    Cattaneo, P. W.; De Gerone, M.; Gatti, F.; Nishimura, M.; Ootani, W.; Rossella, M.; Shirabe, S.; Uchiyama, Y.

    2016-08-01

    A new timing detector measuring ∼ 50 MeV / c positrons is under development for the MEG II experiment, aiming at a time resolution σt ∼ 30 ps. The resolution is expected to be achieved by measuring each positron time with multiple counters made of plastic scintillator readout by silicon photomultipliers (SiPMs). The purpose of this work is to demonstrate the time resolution for ∼ 50 MeV / c positrons using prototype counters. Counters with dimensions of 90 × 40 × 5mm3 readout by six SiPMs (three on each 40 × 5mm2 plane) were built with SiPMs from Hamamatsu Photonics and AdvanSiD and tested in a positron beam at the DAΦNE Beam Test Facility. The time resolution was found to improve nearly as the square root of the number of counter hits. A time resolution σt = 26.2 ± 1.3 ps was obtained with eight counters with Hamamatsu SiPMs. These results suggest that the design resolution is achievable in the MEG II experiment.

  8. Effectiveness of Diffusion Barrier Coatings for Mo-Re Embedded in C/SiC and C/C

    Science.gov (United States)

    Glass, David E.; Shenoy, Ravi N.; Wang, Zeng-Mei; Halbig, Michael C.

    2001-01-01

    Advanced high-temperature cooling applications may often require the elevated-temperature capability of carbon/silicon carbide or carbon/carbon composites in combination with the hermetic capability of metallic tubes. In this paper, the effects of C/SiC and C/C on tubes fabricated from several different refractory metals were evaluated. Though Mo, Nb, and Re were evaluated in the present study, the primary effort was directed toward two alloys of Mo-Re, namely, arc cast Mo-41Re and powder metallurgy Mo-47.5Re. Samples of these refractory metals were subjected to either the PyC/SiC deposition or embedding in C/C. MoSi2(Ge), R512E, and TiB2 coatings were included on several of the samples as potential diffusion barriers. The effects of the processing and thermal exposure on the samples were evaluated by conducting burst tests, microhardness surveys, and scanning electron microscopic examination (using either secondary electron or back scattered electron imaging and energy dispersive spectroscopy). The results showed that a layer of brittle Mo-carbide formed on the substrates of both the uncoated Mo-41Re and the uncoated Mo-47.5Re, subsequent to the C/C or the PyC/SiC processing. Both the R512E and the MoSi2(Ge) coatings were effective in preventing not only the diffusion of C into the Mo-Re substrate, but also the formation of the Mo-carbides. However, none of the coatings were effective at preventing both C and Si diffusion without some degradation of the substrate.

  9. Si and CdTe pixel detector developments at SPring-8

    International Nuclear Information System (INIS)

    Single X-ray photon counting pixel detectors have become the most advanced detector technology in synchrotron radiation experiments recently. In particular, the PILATUS detector based on a silicon sensor has reached a very mature state and represents the world's largest detector in this field. This paper first reports on threshold energy calibrations and the capability of applying an energy-resolved X-ray imaging with PILATUS. Second the design of a cadmium telluride (CdTe) pixel detector is described. A high density and high-atomic number sensor material is required in high energy X-ray applications available at SPring-8. For this purpose we are developing a CdTe pixel detector with the SP8-01 readout ASIC covering a wide dynamic range between 10 and 100 keV and containing lower and upper discriminators.

  10. The effect of interface phonons on operating electron states in three-barrier resonant tunneling structure as an active region of quantum cascade detector

    OpenAIRE

    M.V. Tkach; Ju.O. Seti; Grynyshyn, Y. B.; O.M. Voitsekhivska

    2014-01-01

    The Hamiltonian of electrons interacting with interface phonons in three-barrier resonant tunneling structure is established using the first principles within the models of effective mass and polarization continuum. Using the Green's functions method, the temperature shifts and decay rates of operating electron states are calculated depending on geometric design of three-barrier nano-structure GaAs/AlxGa1-xAs which is an active region of quantum cascade detector. It is established that indepe...

  11. Ta–Rh binary alloys as a potential diffusion barrier between Cu and Si: Stability and failure mechanism of the Ta–Rh amorphous structures

    International Nuclear Information System (INIS)

    Thermodynamic calculations were carried out to derive the Gibbs free energy diagram for the amorphous and crystalline phases in the Ta–Rh system. These calculations predicted that the compositional range for the amorphous Ta–Rh phase was within 37–66 at.% Ta, which was validated by X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HRTEM) observations and resistivity measurements of as-deposited films. The thermodynamic modeling provided a valuable guide for selecting an amorphous composition suitable for diffusion barrier applications. The stability and metallurgical failure mechanism for TaRhx diffusion barriers in contact with Cu and/or Si were investigated by resistivity measurements, XRD analysis and detailed electron microscopy on samples annealed in 5% H2/95% N2 gas for 30 min at various temperatures. Amorphous TaRhx in contact with the Si substrate was stable up to 700 °C, whereupon TaRhx decomposed and reacted to form TaSi2 and RhSi. Si/amorphousTaRhx (13 nm)/Cu stacks, on the other hand, were stable only up to 550 °C. Failure occurred by reaction of Rh with the Si substrate to form RhSi at the interface. The large density of defects formed in the barrier layer as a result of outward diffusion of Rh facilitated diffusion of Cu to the Si/TaRhx interface to form Cu3Si particles. The formation of Cu3Si was observed to trigger further silicidation of the barrier to form a discontinuous TaSi2 layer

  12. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Tornyi, T.G., E-mail: tornyitom@atomki.hu [Department of Physics, University of Oslo (Norway); Institute of Nuclear Research of the Hungarian Academy of Sciences (MTA Atomki), Debrecen (Hungary); Görgen, A.; Guttormsen, M.; Larsen, A.C.; Siem, S. [Department of Physics, University of Oslo (Norway); Krasznahorkay, A. [Institute of Nuclear Research of the Hungarian Academy of Sciences (MTA Atomki), Debrecen (Hungary); Csige, L. [Institute of Nuclear Research of the Hungarian Academy of Sciences (MTA Atomki), Debrecen (Hungary); Max-Planck-Institute for Quantum Optics, D-85748 Garching (Germany)

    2014-02-21

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers 60% of 2π. It was designed to be used in conjunction with the SiRi array of ΔE−E silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly well suited to study the competition of fission and γ decay as a function of excitation energy.

  13. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    Science.gov (United States)

    Tornyi, T. G.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Siem, S.; Krasznahorkay, A.; Csige, L.

    2014-02-01

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers 60% of 2π. It was designed to be used in conjunction with the SiRi array of ΔE-E silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly well suited to study the competition of fission and γ decay as a function of excitation energy.

  14. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    International Nuclear Information System (INIS)

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers 60% of 2π. It was designed to be used in conjunction with the SiRi array of ΔE−E silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly well suited to study the competition of fission and γ decay as a function of excitation energy

  15. A new fission-fragment detector to complement the CACTUS-SiRi setup at the Oslo Cyclotron Laboratory

    CERN Document Server

    Tornyi, Tamás Gábor; Guttormsen, Magne; Larsen, Ann-Cecilie; Siem, Sunniva; Krasznahorkay, Attila; Csige, Lóránt

    2013-01-01

    An array of Parallel Plate Avalanche Counters (PPAC) for the detection of heavy ions has been developed. The new device, NIFF (Nuclear Instrument for Fission Fragments), consists of four individual detectors and covers $60\\%$ of 2$\\pi$. It was designed to be used in conjunction with the SiRi array of ${\\Delta}E-E$ silicon telescopes for light charged particles and fits into the CACTUS array of 28 large-volume NaI scintillation detectors at the Oslo Cyclotron Laboratory. The low-pressure gas-filled PPACs are sensitive for the detection of fission fragments, but are insensitive to scattered beam particles of light ions or light-ion ejectiles. The PPAC detectors of NIFF have good time resolution and can be used either to select or to veto fission events in in-beam experiments with light-ion beams and actinide targets. The powerful combination of SiRi, CACTUS, and NIFF provides new research opportunities for the study of nuclear structure and nuclear reactions in the actinide region. The new setup is particularly...

  16. The residual stress instrument with optimized Si(2 2 0) monochromator and position-sensitive detector at HANARO

    Science.gov (United States)

    Lee, Chang-Hee; Moon, Myung-Kook; Em, Vyacheslav T.; Choi, Young-Hyun; Cheon, Jong-Kyu; Nam, Uk-Won; Kong, Kyung-Nam

    2005-06-01

    An upgraded residual stress instrument at the HANARO reactor of the KAERI is described. A horizontally focusing bent perfect crystal Si(2 2 0) monochromator (instead of a mosaic vertical focusing Ge monochromator) is installed in a drum with a tunable (2 θM=0-60°) take-off angle/wavelength. A specially designed position-sensitive detector (60% efficiency for λ=1.8 A) with 200 mm (instead of 100 mm) high-active area is used. There are no Soller type collimators in the instrument. The minimum possible monochromator to sample distance, L=2 m, and sample to detector distance, L=1.2 m, were found to be optimal. The new PSD and bent Si(2 2 0) monochromator combined with the possibility of selecting an appropriate wavelength resulted in about a ten-fold gain in data collection rate. The optimal reflections of austenitic and ferritic steels, aluminum and nickel for stress measurements with a Si(2 2 0) monochromator were chosen experimentally. The ability of the instrument to make strain measurements deep inside the austenitic and ferritic steels has been tested. For the chosen reflections and wavelengths, no shift of peak position (apparent strain) was observed up to 56 mm length of path.

  17. Design and spectrum calculation of 4H-SiC thermal neutron detectors using FLUKA and TCAD

    Science.gov (United States)

    Huang, Haili; Tang, Xiaoyan; Guo, Hui; Zhang, Yimen; Zhang, Yimeng; Zhang, Yuming

    2016-10-01

    SiC is a promising material for neutron detection in a harsh environment due to its wide band gap, high displacement threshold energy and high thermal conductivity. To increase the detection efficiency of SiC, a converter such as 6LiF or 10B is introduced. In this paper, pulse-height spectra of a PIN diode with a 6LiF conversion layer exposed to thermal neutrons (0.026 eV) are calculated using TCAD and Monte Carlo simulations. First, the conversion efficiency of a thermal neutron with respect to the thickness of 6LiF was calculated by using a FLUKA code, and a maximal efficiency of approximately 5% was achieved. Next, the energy distributions of both 3H and α induced by the 6LiF reaction according to different ranges of emission angle are analyzed. Subsequently, transient pulses generated by the bombardment of single 3H or α-particles are calculated. Finally, pulse height spectra are obtained with a detector efficiency of 4.53%. Comparisons of the simulated result with the experimental data are also presented, and the calculated spectrum shows an acceptable similarity to the experimental data. This work would be useful for radiation-sensing applications, especially for SiC detector design.

  18. Si(Li)探测器测谱中产生伪峰现象的分析%ANALYZING THE PHENOMENA OF FAKE PEAK PRODUCED IN Si(Li) DETECTOR'S MEASURING SPECTRUM

    Institute of Scientific and Technical Information of China (English)

    张开春; 吴丽萍; 周厚全; 李志勇

    2001-01-01

    The Be window is destroyed by chance during using the Si(Li) detector. After it is repaired, the detector is used to measure characteristic X-ray of following elements of V, Fe, Ni, Cu, Zn and Pb. The concomitent fake peak appears going with the photoelectric peak of above mentioned elements, and the ratio of two peaks' energy is nearly a constant. By experiment test and reason analysis, it is found that the fare peak is resulted from Li ions' contrary diraction drift in Si(Li) detector, which is caused by the suddenly sharp change of outward the degree of vacuum and high voltage.

  19. Preparation and characterization of bilayer Ta-Si-N/Ti diffusion barrier layer%Ta-Si-N/Ti双层结构扩散阻挡层的制备与表征

    Institute of Scientific and Technical Information of China (English)

    邓鹏远; 瞿金凤

    2013-01-01

    Ta-Si-N (10nm)/Ti(20nm) bilayer diffusion barrier was grown between n-type (100) silicon wafer and Cu film by RF reactive magnetron sputtering. The Cu/Ta-Si-N/Ti/Si samples were subsequently annealed at different temperatures ranging from 600 to 800℃in N2 gas for 1 h. In order to investigate the thermal stability of the barrier structure after annealing, X-ray diffraction, scanning electron microscopy and 4-point probe technique were performed, respectively. The results reveal that Ta-Si-N film deposited on Ti film is amorphous. In addition, the diffusion of Ti atoms into Si substrate results in TiSi2 which decreases the contact resistance between barrier Si and Ta-Si-N(10nm)/Ti(20nm) bilayer can serve as effective diffusion barriers up to 750℃.%  采用射频磁控溅射的方法在Si(100)衬底和Cu膜间制备了Ta-Si-N(10nm)/Ti(20nm)双层结构的扩散阻挡层。Cu/Ta-Si-N/Ti/Si样品在高纯氮气的保护下从600至800℃退火1小时。通过四探针电阻测试仪(FPP)、SEM、XRD研究了Cu/Ta-Si-N/Ti/Si系统在退火过程中的热稳定性。研究结果表明:沉积到Ti膜上的Ta-Si-N膜为非晶态结构;Cu/Ta-Si-N/Ti/Si样品700℃以上退火后Ti原子扩散到Si中形成的TiSi2能有效地降低Ta-Si-N与Si之间的接触电阻;Ta-Si-N/Ti阻挡层750℃退火后仍能有效地阻止Cu的扩散。

  20. Investigation of Thickness Dependence of Metal Layer in Al/Mo/4H-SiC Schottky Barrier Diodes.

    Science.gov (United States)

    Lee, Seula; Lee, Jinseon; Kang, Tai-Young; Kyoung, Sinsu; Jung, Eun Sik; Kim, Kyung Hwan

    2015-11-01

    In this paper, we present the preparation and characterization of Schottky barrier diodes based on silicon carbide with various Schottky metal layer thickness values. In this structure, molybdenum and aluminum were employed as the Schottky barrier metal and top electrode, respectively. Schottky metal layers were deposited with thicknesses ranging from 1000 to 3000 Å, and top electrodes were deposited with thickness as much as 3000 Å. The deposition of both metal layers was performed using the facing target sputtering (FTS) method, and the fabricated samples were annealed with the tubular furnace at 300 degrees C under argon ambient for 10 min. The Schottky barrier height, series resistance, and ideality factor was calculated from the forward I-V characteristic curve using the methods proposed by Cheung and Cheung, and by Norde. For as-deposited Schottky diodes, we observed an increase of the threshold voltage (V(T)) as the thickness of the Schottky metal layer increased. After the annealing, the Schottky barrier heights (SBHs) of the diodes, including Schottky metal layers of over 2000 Å, increased. In the case of the Schottky metal layer deposited to 1000 Å, the barrier heights decreased due to the annealing process. This may have been caused by the interfacial penetration phenomenon through the Schottky metal layer. For variations of V(T), the SBH changed with a similar tendency. The ideality factor and series resistance showed no significant changes before or after annealing. This indicates that this annealing condition is appropriate for Mo SiC structures. Our results confirm that it is possible to control V(T) by adjusting the thickness of the Schottky metal layer.

  1. A comparison of XEDS and EELS with the use of conventional beryllium window and windowless Si(Li) detectors

    International Nuclear Information System (INIS)

    The use of electron energy loss spectroscopy (EELS) for light-element identification is now a well-established technique. Although not a new concept, modified Si(Li) detectors with the conventional beryllium window replaced by a ultra-thin aluminum-coated parylene window (UTW), or with the beryllium completely removed for windowless (WL) operation, have now become routinely available. Since both systems can now be easily interfaced to modern analytical electron microscopes (AEMs) it becomes relevant to determine experimentally the relative merits of the two different techniques for light-element identification and subsequent quantification in both simple systems and complex materials problems, such as precipitate identification in multicomponent alloys. In this preliminary study, the authors have systematically studied the relationship between EELS and XEDS (using a WL detector) for elements ranging from lithium through gallium, with the exception of neon and argon, as well as typical problems in precipitate analysis in thermally aged 316 stainless steel specimens

  2. Validated simulation for LYSO:Ce scintillator based PET detector modules built on fully digital SiPM arrays

    International Nuclear Information System (INIS)

    In the recent years new digital photon counter devices (also known as silicon photomultipliers, SiPMs) were designed and manufactured to be used specifically in positron emission tomography (PET) scanners. These finely pixelated devices opened new opportunities in PET detector development, hence their application with monolithic scintillator crystals now are of particular interest. We worked out a simulation tool and a corresponding validation method to assist the optimization and characterization of such PET detector modules. During our work we concentrated on the simulation of SPADnet sensors and the LYSO:Ce scintillator material. Validation of our algorithms combines measurements and simulations performed on UV-excited detector modules. In this paper we describe the operation of the simulation method in detail and present the validation scheme for two demonstrative PET detector-like modules: one built of a scintillator with black-painted faces and another with polished faces. By evaluating the results we show that the shape deviation of the average light distributions is lower than 13%, and the pixel count statistics follow Poisson distribution for both measurement and simulation. The calculated total count values have less than 10% deviation from the measured ones

  3. Superconducting single X-ray photon detector based on W0.8Si0.2

    CERN Document Server

    Zhang, X; Schilling, A

    2016-01-01

    We fabricated a superconducting single X-ray photon detector based on W0.8Si0.2, and we characterized its basic detection performance for keV-photons at different temperatures. The detector has a critical temperature of 4.97 K, and it is able to be operated up to 4.8 K, just below the critical temperature. The detector starts to react to X-ray photons at relatively low bias currents, less than 1% of Ic at T = 1.8 K, and it shows a saturated count rate dependence on bias current at all temperatures, indicating that the optimum internal quantum efficiency can always be reached. Dark counts are negligible up to the highest investigated bias currents (99% of Ic) and operating temperature (4.8 K). The latching effect affects the detector performance at all temperatures due to the fast recovery of the bias current; however, further modifications of the device geometry are expected to reduce the tendency for latching.

  4. A low cost network of spectrometer radiation detectors based on the ArduSiPM a compact transportable Software/Hardware Data Acquisition system with Arduino DUE

    CERN Document Server

    Bocci, Valerio; Iacoangeli, Francesco; Nuccetelli, Massimo; Recchia, Luigi

    2015-01-01

    The necessity to use Photo Multipliers (PM) as light detector limited in the past the use of crystals in radiation handled device preferring the Geiger approach. The Silicon Photomultipliers (SiPMs) are very small and cheap, solid photon detectors with good dynamic range and single photon detection capability, they are usable to supersede in some application cumbersome and difficult to use Photo Multipliers (PM). A SiPM can be coupled with a scintillator crystal to build efficient, small and solid radiation detector. A cost effective and easily replicable Hardware software module for SiPM detector readout is made using the ArduSiPM solution [1]. The ArduSiPM is an easily battery operable handled device using an Arduino DUE (an open Software/Hardware board) as processor board and a piggy-back custom designed board (ArduSiPM Shield), the Shield contains all the blocks features to monitor, set and acquire the SiPM using internet network.

  5. Time resolution below 100 ps for the SciTil detector of PANDA employing SiPM

    CERN Document Server

    Brunner, S E; Marton, J; Orth, H; Suzuki, K

    2013-01-01

    The barrel time-of-flight (TOF) detector for the PANDA experiment at FAIR in Darmstadt is planned as a scintillator tile hodoscope (SciTil) using 8000 small scintillator tiles. It will provide fast event timing for a software trigger in the otherwise trigger-less data acquisition scheme of PANDA, relative timing in a multiple track event topology as well as additional particle identification in the low momentum region. The goal is to achieve a time resolution of sigma ~ 100 ps. We have conducted measurements using organic scintillators coupled to Silicon Photomultipliers (SiPM). The results are encouraging such that we are confident to reach the required time resolution.

  6. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Science.gov (United States)

    Verbitskaya, Elena; Eremin, Vladimir; Zabrodskii, Andrei; Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R.; Egorov, Nicolai; Härkönen, Jaakko

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×1016 p/cm2. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment.

  7. Time dependent changes in Schottky barrier mapping of the W/Si(001) interface utilizing ballistic electron emission microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Durcan, Chris A.; Balsano, Robert [College of Nanoscale Science and Engineering, State University of New York, Albany, New York 12203 (United States); LaBella, Vincent P., E-mail: vlabella@albany.edu [Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, New York 12203 (United States)

    2015-06-28

    The W/Si(001) Schottky barrier height is mapped to nanoscale dimensions using ballistic electron emission microscopy (BEEM) over a period of 21 days to observe changes in the interface electrostatics. Initially, the average spectrum is fit to a Schottky barrier height of 0.71 eV, and the map is uniform with 98% of the spectra able to be fit. After 21 days, the average spectrum is fit to a Schottky barrier height of 0.62 eV, and the spatial map changes dramatically with only 27% of the spectra able to be fit. Transmission electron microscopy shows the formation of an ultra-thin tungsten silicide at the interface, which increases in thickness over the 21 days. This increase is attributed to an increase in electron scattering and the changes are observed in the BEEM measurements. Interestingly, little to no change is observed in the I-V measurements throughout the 21 day period.

  8. Time dependent changes in Schottky barrier mapping of the W/Si(001) interface utilizing ballistic electron emission microscopy

    International Nuclear Information System (INIS)

    The W/Si(001) Schottky barrier height is mapped to nanoscale dimensions using ballistic electron emission microscopy (BEEM) over a period of 21 days to observe changes in the interface electrostatics. Initially, the average spectrum is fit to a Schottky barrier height of 0.71 eV, and the map is uniform with 98% of the spectra able to be fit. After 21 days, the average spectrum is fit to a Schottky barrier height of 0.62 eV, and the spatial map changes dramatically with only 27% of the spectra able to be fit. Transmission electron microscopy shows the formation of an ultra-thin tungsten silicide at the interface, which increases in thickness over the 21 days. This increase is attributed to an increase in electron scattering and the changes are observed in the BEEM measurements. Interestingly, little to no change is observed in the I-V measurements throughout the 21 day period

  9. Large area Si low-temperature light detectors with Neganov-Luke effect

    CERN Document Server

    Biassoni, M; Capelli, S; Cassina, L; Clemenza, M; Cremonesi, O; Faverzani, M; Ferri, E; Giachero, A; Gironi, L; Giordano, C; Gotti, C; Maino, M; Margesin, B; Nucciotti, A; Pavan, M; Pessina, G; Previtali, E; Puiu, A; Sisti, M; Terranova, F

    2015-01-01

    Next generation calorimetric experiments for the search of rare events rely on the detection of tiny amounts of light (of the order of 20 optical photons) to discriminate and reduce background sources and improve sensitivity. Calorimetric detectors are the simplest solution for photon detection at cryogenic (mK) temperatures. The development of silicon based light detectors with enhanced performance thanks to the use of the Neganov-Luke effect is described. The aim of this research line is the production of high performance detectors with industrial-grade reproducibility and reliability.

  10. Monolithic scintillators and SiPMs in time-of-flight PET detectors

    OpenAIRE

    Dam, H T van

    2012-01-01

    Positron emission tomography (PET) is one of the key medical imaging modalities in the diagnosis and staging of e.g. cancer and cardiovascular diseases. The image formation is based on the measurement of annihilation photon pairs in the detector ring of the PET scanner. The diagnostic value of a PET image depends crucially on the image quality, which to a large extent is determined by the performance of the PET detectors. Therefore, we have investigated a novel detector concept based on a mon...

  11. Fixed pattern deviations in Si pixel detectors measured using the Medipix 1 readout chip

    CERN Document Server

    Tlustos, L; Davidson, D; Heijne, Erik H M; Mikulec, B

    2003-01-01

    Dopant fluctuations and other defects in silicon wafers can lead to systematic errors in several parameters in particle or single-photon detection. In imaging applications non-uniformities in sensors or readout give rise to fixed pattern image noise and degradation of achievable spatial resolution for a given flux. High granularity pixel detectors offer the possibility to investigate local properties of the detector material on a microscopic scale. In this paper, we study fixed pattern detection fluctuations and detector inhomogeneities using the Medipix 1 readout chip. Low-frequency fixed pattern signal deviations due to dopant inhomogeneities can be separated from high-frequency deviations.

  12. Modified-chitosan/siRNA nanoparticles downregulate cellular CDX2 expression and cross the gastric mucus barrier.

    Directory of Open Access Journals (Sweden)

    Ana Sadio

    Full Text Available Development of effective non-viral vectors is of crucial importance in the implementation of RNA interference in clinical routine. The localized delivery of siRNAs to the gastrointestinal mucosa is highly desired but faces specific problems such as the stability in gastric acidity conditions and the presence of the mucus barrier. CDX2 is a transcription factor critical for intestinal differentiation being involved in the initiation and maintenance of gastrointestinal diseases. Specifically, it is the trigger of gastric intestinal metaplasia which is a precursor lesion of gastric cancer. Its expression is also altered in colorectal cancer, where it may constitute a lineage-survival oncogene. Our main objective was to develop a nanoparticle-delivery system of siRNA targeting CDX2 using modified chitosan as a vector. CDX2 expression was assessed in gastric carcinoma cell lines and nanoparticles behaviour in gastrointestinal mucus was tested in mouse explants. We show that imidazole-modified chitosan and trimethylchitosan/siRNA nanoparticles are able to downregulate CDX2 expression and overpass the gastric mucus layer but not colonic mucus. This system might constitute a potential therapeutic approach to treat CDX2-dependent gastric lesions.

  13. Direct conversion Si and CdZnTe detectors for digital mammography

    CERN Document Server

    Yin Shi Shi; Maeding, D; Mainprize, J; Mawdsley, G; Yaffe, M J; Gordon, E E; Hamilton, W J

    2000-01-01

    Hybrid pixel detector arrays that convert X-rays directly into charge signals are under development at NOVA for application to digital mammography. This technology also has wide application possibilities in other fields of radiology or in industrial imaging, nondestructive evaluation (NDE) and nondestructive inspection (NDI). These detectors have potentially superior properties compared to either emulsion-based film-screen systems which has nonlinear response to X-rays, or phosphor-based detectors in which there is an intermediate step of X-ray to light photon conversion (Feig and Yaffe, Radiol. Clinics North America 33 (1995) 1205-1230). Potential advantages of direct conversion detectors are high quantum efficiencies (QE) of 98% or higher (for 0.3 mm thick CdZnTe detector with 20 keV X-rays), improved contrast, high sensitivity and low intrinsic noise. These factors are expected to contribute to high detective quantum efficiency (DQE). The prototype hybrid pixel detector developed has 50x50 mu m pixel size,...

  14. The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)

    CERN Document Server

    Watanabe, Shin; Fukazawa, Yasushi; Ichinohe, Yuto; Takeda, Shin'ichiro; Enoto, Teruaki; Fukuyama, Taro; Furui, Shunya; Genba, Kei; Hagino, Kouichi; Harayama, Astushi; Kuroda, Yoshikatsu; Matsuura, Daisuke; Nakamura, Ryo; Nakazawa, Kazuhiro; Noda, Hirofumi; Odaka, Hirokazu; Ohta, Masayuki; Onishi, Mitsunobu; Saito, Shinya; Sato, Goro; Sato, Tamotsu; Takahashi, Tadayuki; Tanaka, Takaaki; Togo, Atsushi; Tomizuka, Shinji

    2015-01-01

    The Soft Gamma-ray Detector (SGD) is one of the instrument payloads onboard ASTRO-H, and will cover a wide energy band (60--600 keV) at a background level 10 times better than instruments currently in orbit. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and cadmium telluride (CdTe) sensors. The design of the SGD Compton camera has been finalized and the final prototype, which has the same configuration as the flight model, has been fabricated for performance evaluation. The Compton camera has overall dimensions of 12 cm x 12 cm x 12 cm, consisting of 32 layers of Si pixel sensors and 8 layers of CdTe pixel sensors surrounded by 2 layers of CdTe pixel sensors. The detection efficiency of the Compton camera reaches about 15% and 3% for 100 keV and 511 keV gamma rays, respectively. The pixel pitch of the Si and CdTe sensors is 3.2 mm, and ...

  15. Electron backscattering on Si(Li) detectors and determination of the transmission curve of a Mini-Orange Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Guerro, Leonardo, E-mail: leonardo.guerro@unicam.it [Division of Physics, School of Science and Technology, University of Camerino, Camerino (Italy); INFN-Sezione di Perugia (Italy); Blasi, Nives [INFN-Sezione di Milano (Italy); Saltarelli, Alessandro [Division of Physics, School of Science and Technology, University of Camerino, Camerino (Italy); INFN-Sezione di Perugia (Italy)

    2014-03-01

    A detailed electron backscattering analysis in Si(Li) detectors was done in order to evaluate the response function of the Mini-Orange Spectrometer. The analysis was performed via Monte Carlo simulations and by measuring the energy and the angular dependencies without and with the insertion of the Mini-Orange Spectrometer in the detection system, combining data taken with a continuous β{sup −} source ({sup 90}Sr) with those from discrete electron transitions of an electron conversion source ({sup 207}Bi). A simple but accurate method is described to determine the transmission function T(E) of the Mini-Orange. - Highlights: • We analyze electron backscattering in Si(Li) detectors. • We evaluate the response function of a Mini-Orange Spectrometer. • We perform Monte Carlo simulations and measure MOS energy and angular dependencies. • Data are taken with a continuous source combined with a discrete conversion source. • An accurate method is described to determine the transmission of a Mini-Orange.

  16. Estimation of moisture barrier ability of thin SiNx single layer on polymer substrates prepared by Cat-CVD method

    International Nuclear Information System (INIS)

    The SiNx films with the thickness of 50 nm were prepared by Cat-CVD method on the cyclic olefin copolymer (COC) and the polyethylene terephthalate (PET) substrates, and their moisture barrier abilities were evaluated. MOCON measurement method and Ca degradation test showed the moisture permeation results of 0.02 g/(m2 day) for PET substrate and 0.006 g/(m2 day) for COC substrate after SiNx deposition. Applying the simple model of gas barrier property, it was estimated that the Cat-CVD method achieves the high coverage ratio of over 99% for SiNx film on these substrates, and the moisture permeation rate of single SiNx film with the thickness of 50 nm was estimated to be 0.0045 g/(m2 day)

  17. 1K X 1K Si:As IBC detector arrays for JWST MIRI and other applications

    Science.gov (United States)

    Love, Peter J.; Hoffman, Alan W.; Lum, Nancy A.; Ando, Ken J.; Ritchie, William D.; Therrien, Neil J.; Toth, Andrew G.; Holcombe, Roger S.

    2004-09-01

    1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by Raytheon Vision Systems (RVS) for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). The devices are also suitable for other low-background applications. The Si:As IBC detectors respond out to ~28 microns, covering an important mid-IR region beyond the 1-5 micron range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. A mid-infrared instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. The greatly reduced thermal backgrounds achievable on a space platform (compared to airborne or ground-based platforms) allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. We describe results of the development of a new 1024 × 1024 Si:As IBC array with 25-micron pixels that responds with high quantum efficiency over the wavelength range 5 to 28 microns. The previous generation's largest, most sensitive IR detectors at these wavelengths were the 256 × 256/30-micron pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument. JWST MIRI detector requirements will be reviewed and some model results for IBC device performance will be presented. The IBC detector architecture will be described and the SB305 Readout Integrated Circuit (ROIC), developed specifically for JWST MIRI, will be discussed. The SB305 ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise is expected to be less than 20 e- rms with Fowler-8 sampling at an operating temperature of 7

  18. X-ray photoelectron spectroscopy investigation of the Schottky barrier at low-k a-SiO(C):H/Cu interfaces

    International Nuclear Information System (INIS)

    In order to understand the fundamental mechanisms involved in electrical leakage in low-k/Cu interconnects, we have utilized x-ray photoelectron spectroscopy to determine the Schottky barrier present at interfaces formed by plasma enhanced chemical vapor deposition of low-k a-SiOxCy:H thin films on polished Cu substrates. We find the Schottky Barrier at this interface to range widely from 1 to >4 eV and to be dependent on the amount of network carbon incorporated into the a-SiOC:H thin films.

  19. Investigation on Coating Uniformity of High-Temperature Alloy with SiC Thermal Barrier Coating Using Pulsed Infrared Thermographic Technique

    Science.gov (United States)

    Liu, J. Y.; Tang, Q. J.; Wang, Y.; Gong, J. L.; Qin, L.

    2015-06-01

    The SiC thermal barrier coating thickness uniformity of a high-temperature alloy was investigated using a pulsed infrared thermographic image. A thermal quadrupole method is used to solve a one-dimensional thermal conduction model. The temperature of the high-temperature alloy with SiC coating is directly affected by the pulse intensity of optical excitation; furthermore, the relation between the SiC thermal barrier coating thickness and temperature difference is obtained. Pulsed phase thermography and principal component analysis are applied to extract the characteristic information from thermal image sequences, and the signal-to-noise ratio of the thermal wave signal is clearly improved. The thermal contrast of the SiC thermal barrier coating thickness is related to the optical pulse intensity and infrared camera frame rate. Furthermore, a relatively simple quantitative method is developed to estimate the SiC thermal barrier coating thickness uniformity of the high-temperature alloy, and the coating thickness measurement using pulsed thermographic imaging is in very good agreement with the actual coating thickness value.

  20. Improved germanium well detectors

    International Nuclear Information System (INIS)

    Germanium well detectors with metal surface barrier contact are comparable for general use with conventional germanium coaxial detectors. They offer very high sensitivity, the highest presently available

  1. Preparation of Al-Cr-Si oxide tritium permeation barrier by double glow plasma technology

    International Nuclear Information System (INIS)

    Al-Cr-Si oxide coatings were prepared on 316L stainless steel by double glow plasma surface alloying technique in order to promote the capability against tritium permeation. Microstructures and compositions of the coatings were studied by scanning electron microscope, transmission electron microscope and X-ray diffraction. Adhesion strength of the oxide coatings was tested by scratch adhesion test and thermal shock test. The results showed that dense and continuous Al2O3 films were formed on the substrate owing to the addition of elements Cr and Si. Besides, the spinel-type composite metal oxide Fe(AlCr)2O4 was formed of Al2O3 and iron/chromic oxide in the outer layer. The coatings prepared at oxygen flow rate of 10 standard cubic centimeter per minute exhibited the best microstructure and mechanical properties with a bonding force of 68 N. No cracks were found in the coatings after thermal shock testing. (authors)

  2. Plasmonic effect of Ag nanoparticles in a SiON antireflective coating: engineering rules and physical barrier

    Science.gov (United States)

    Lecler, S.; Bastide, S.; Tan, J.; Qu, M.; Slaoui, A.; Fix, T.

    2016-10-01

    Surface plasmon polaritons have been proposed in the architectures of several solar cells as a way to enhance light collection and thus to increase their efficiency. Here, Ag nanoparticles (NPs) are embedded in a SiON antireflective layer using an electroless technique. The plasmonic effects are modeled and observed experimentally for NPs 5 to 200 nm in size. The systematic comparison of scattering and extinction efficiencies computed as a function of the NPs and surrounding medium properties allows establishing engineering rules, validated by the experimental measurements. The fact that Ag NPs larger than 30 nm mainly contribute to light scattering and therefore to optical path enlargement (green-red light), whereas those smaller than 15 nm absorb light by light trapping (blue-green), is demonstrated and physically explained. A physical barrier making it impossible to shift the dominant resonance beyond 650 nm is pointed out.

  3. Development Status and Performance Comparisons of Environmental Barrier Coating Systems for SiCSiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan

    2016-01-01

    Environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft turbine engine systems, because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. This paper presents current NASA EBC-CMC development emphases including: the coating composition and processing improvements, laser high heat flux-thermal gradient thermo-mechanical fatigue - environmental testing methodology development, and property evaluations for next generation EBC-CMC systems. EBCs processed with various deposition techniques including Plasma Spray, Electron Beam - Physical Vapor Deposition, and Plasma Spray Physical Vapor Deposition (PS-PVD) will be particularly discussed. The testing results and demonstrations of advanced EBCs-CMCs in complex simulated engine thermal gradient cyclic fatigue, oxidizing-steam and CMAS environments will help provide insights into the coating development strategies to meet long-term engine component durability goals.

  4. A comparative study of low dielectric constant barrier layer, etch stop and hardmask films of hydrogenated amorphous Si-(C, O, N)

    International Nuclear Information System (INIS)

    New barrier layer, etch stop and hardmask films, including hydrogenated amorphous a-SiCx:H (SiC), a-SiCxOy:H (SiCO), and a-SiCxNy:H (SiCN) films with a dielectric constant (k) approximately 4.3, are produced using the plasma-enhanced chemical vapor deposition technique. The chemical and structural nature, and mechanical properties of these films are characterized using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and nano-indentation. The leakage current density and breakdown electric field are investigated by a mercury probe on a metal-insulator-semiconductor structure. The properties of the studied films indicate that they are potential candidates as barrier layer, etch stop and hardmask films for the advanced interconnect technology. The SiC film shows a high leakage current density (1.3x10-7 A/cm2 at 1.0 MV/cm) and low breakdown field (1.2 MV/cm at 1.0x10-6 A/cm2). Considering the mechanical and electrical properties requirements of the interconnect process, SiCN might be a good choice, but the N content may result in via poison problem. The low leakage current (1.2x10-9 A/cm2 at 1.0 MV/cm), high breakdown field (3.1 MV/cm at 1.0x10-6 A/cm2), and relative high hardness (5.7 GPa) of the SiCO film indicates a good candidate as a barrier layer, etch stop, or hardmask

  5. Monolithic scintillators and SiPMs in time-of-flight PET detectors

    NARCIS (Netherlands)

    Van Dam, H.T.

    2012-01-01

    Positron emission tomography (PET) is one of the key medical imaging modalities in the diagnosis and staging of e.g. cancer and cardiovascular diseases. The image formation is based on the measurement of annihilation photon pairs in the detector ring of the PET scanner. The diagnostic value of a PET

  6. Characterization and modeling of neutron induced transient response changes in Si:As IBC detectors

    International Nuclear Information System (INIS)

    The authors have conducted an analysis of the temporal response of an IBC detector in the presence of neutron generated compensating acceptor states under typical operating conditions. In this paper a model is presented which describes the observed transient response changes in the regime dominated by dielectric relaxation

  7. Pulse height defect of energetic heavy ions in ion-implanted Si detectors

    Science.gov (United States)

    Pasquali, G.; Casini, G.; Bini, M.; Calamai, S.; Olmi, A.; Poggi, G.; Stefanini, A. A.; Saint-Laurent, F.; Steckmeyer, J. C.

    1998-02-01

    The pulse height defect in ion-implanted silicon detectors for elastically scattered 93Nb, 100Mo, 116Sn, 120Sn and 129Xe ions, at energies ranging from about 4 to 25 A MeV has been measured. The results are compared with two widely used parametrizations taken from the literature.

  8. Pulse height defect of energetic heavy ions in ion-implanted Si detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, G.; Casini, G.; Bini, M.; Calamai, S.; Olmi, A.; Poggi, G.; Stefanini, A.A. [Istituto Nazionale di Fisica Nucleare, Florence (Italy)]|[Univ. of Florence (Italy); Saint-Laurent, F. [DRFC/STEP, CEN Cadarache, 13108 Saint Paul Lez Durance Cedex (France); Steckmeyer, J.C. [Laboratoire de Physique Corpuscolaire, ISMRA, 14050 Caen Cedex (France)

    1998-03-01

    The pulse height defect in ion-implanted silicon detectors for elastically scattered {sup 93}Nb, {sup 100}Mo, {sup 116}Sn, {sup 120}Sn and {sup 129}Xe ions, at energies ranging from about 4 to 25 A MeV has been measured. The results are compared with two widely used parametrizations taken from the literature. (orig.). 14 refs.

  9. 总剂量辐照SiO2/6H-SiC引起的界面势垒变化%Total Dose Radiation Induced Interface Barriers Changing of SiO2/6H-SiC Structure

    Institute of Scientific and Technical Information of China (English)

    牟维兵; 龚敏; 曹群

    2011-01-01

    辐照会引起MOS器件电介质氧化物与半导体界面势垒变化,影响其工作性能和可靠性.测量了n型6H-SiC MOS电容辐照105rad(Si)剂量前后的Ⅰ-Ⅴ线,通过Fowler-Nordheim(F-N)隧道电流拟合,得到了界面势垒的大小,辐照前的为2.596 eV,辐照后降为1.492eV.界面势垒变化主要是由辐照产生的界面态引起的.%The barrier between oxide and SiC interface would change due to irradiation.And operating characteristics would be affected. I-V curves of n-type 6H-SiC MOS capacitor before and after 105rad(Si) irradiation are measured. Interface barriers are calculated by FowlerNordheim tunneling fit. The barrier before irradiation is 2. 446 eV, and that is 1. 604 eV after irradiation. Shift of barrier is main due to acceptor type interface states produced by irradiation.

  10. Emission reduction in SI engine using ethanol – gasoline blends on thermal barrier coated pistons

    OpenAIRE

    C.Ananda Srinivasan and C.G.Saravanan

    2010-01-01

    In this study, the effects of ethanol and unleaded gasoline with Isoheptanol blends on multi- cylinder SI engine were investigated. The test fuels were prepared using 99.9% pure ethanol and unleaded gasoline with Isoheptanol blend, in the ratio of E 60 + 2.0 Isoheptanol, E 50 + 1.0 Isoheptanol. In this work the performance, emission and combustion tests were conducted in multi-cylinder petrol engine. The experimental results reveal an increase in brake thermal efficiency on the use of test fu...

  11. TU-F-18C-08: Micro-Calcification Detectability Using Spectral Breast CT Based On a Si Strip Detector

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H; Ding, H; Molloi, S [University of California, Irvine, CA (United States); Barber, W; Iwanczyk, J [DxRay Inc., Northridge, CA (United States)

    2014-06-15

    Purpose: To investigate the feasibility of micro-calcification (μCa) detectability by using an energy-resolved photon-counting Si strip detector for spectral breast computed tomography (CT). Methods: A bench-top CT system was constructed using a tungsten anode x-ray source with a focal spot size of 0.8 mm and a single line 256-pixel Si strip photon counting detector with a pixel pitch of 100 μm. The slice thickness was 0.5 mm. Five different size groups of calcium carbonate grains, from 105 to 215 μm in diameter, were embedded in a cylindrical resin phantom with a diameter of 16 mm to simulate μCas. The phantoms were imaged at 65 kVp with an Entrance Skin Air Kerma (ESAK) of 1.2, 3, 6, and 8 mGy. The images were reconstructed using a standard filtered back projection (FBP) with a ramp filter. A total of 200 μCa images (5 different sizes of μCas × 4 different doses × 10 images for each setting) were combined with another 200 control images without μCas, to ultimately form 400 images for the reader study. The images were displayed in random order to three blinded observers, who were asked to give a binary score on each image regarding the presence of μCas. The μCa detectability for each image was evaluated in terms of binary decision theory metrics. The sensitivity, specificity, and accuracy were calculated to study the size and dose-dependence for μCa detectability. Additionally, the influence of the partial volume effect on the μCa detectability was investigated by simulation. Results: For a μCa larger than 140 μm in diameter, detection accuracy of above 90 % was achieved with the investigated prototype spectral CT system at ESAK of 1.2 mGy. Conclusion: The proposed Si strip detector is expected to offer superior image quality with the capability to detect μCas for low dose breast imaging.

  12. Investigation of amorphous RuMoC alloy films as a seedless diffusion barrier for Cu/p-SiOC:H ultralow-k dielectric integration

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Guohua [Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences, Shenzhen (China); The Chinese University of Hong Kong, Shatin, Hong Kong (China); Liu, Bo [Sichuan University, Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Chengdu (China); Li, Qiran [CNRS-Universite Paris Sud UMR 8622, Institut d' Electronique Fondamentale, Orsay (France)

    2015-08-15

    Ultrathin RuMoC amorphous films prepared by magnetron co-sputtering with Ru and MoC targets in a sandwiched scheme Si/p-SiOC:H/RuMoC/Cu were investigated as barrier in copper metallization. The evolution of final microstructure of RuMoC alloy films show sensitive correlation with the content of doped Mo and C elements and can be easily controlled by adjusting the sputtering power of the MoC target. There was no signal of interdiffusion between the Cu and SiOC:H layer in the sample of Cu/RuMoC/p-SiOC:H/Si, even annealing up to 500 C. Very weak signal of oxygen have been confirmed in the RuMoC barrier layer both as-deposited and after being annealed, and a good performance on preventing oxygen diffusion has been proved. Leakage current and resistivity evaluations also reveal the excellent thermal reliability of this Si/p-SiOC:H/RuMoC/Cu film stack at the temperatures up to 500 C, indicating its potential application in the advanced barrierless Cu metallization. (orig.)

  13. A Fast Calibration System for SiPM Based Scintillator HCAL Detector

    CERN Document Server

    Polak, I

    2015-01-01

    with mid-range a fixed-intensity light pulse. The full SiPM response function is cross-checked by varying the light intensity from zero to the saturation level. In calibration systems we developed, we concentrate especially on the aspect a high dynamic range of pre...

  14. Key Durability Issues with Mullite-Based Environmental Barrier Coatings for Si-Based Ceramics

    Science.gov (United States)

    Lee, Kang N.

    2000-01-01

    Plasma-sprayed mullite (3Al2O3.2SiO2) and mullite/yttria-stabilized-zirconia (YSZ) dual layer coatings have been developed to protect silicon -based ceramics from environmental attack. Mullite-based coating systems show excellent durability in air. However, in combustion environments, corrosive species such as molten salt or water vapor penetrate through cracks in the coating and attack the Si-based ceramics along the interface. Thus the modification of the coating system for enhanced crack-resistance is necessary for long-term durability in combustion environments. Other key durability issues include interfacial contamination and coating/substrate bonding. Interfacial contamination leads to enhanced oxidation and interfacial pore formation, while a weak coating/substrate bonding leads to rapid attack of the interface by corrosive species, both of which can cause a premature failure of the coating. Interfacial contamination can be minimized by limiting impurities in coating and substrate materials. The interface may be modified to improve the coating/substrate bond.

  15. Planar electron-tunneling Si/Si0.7Ge0.3 triple-barrier resonant tunneling diode formed on undoped strain-relaxed buffer with flat surface

    Science.gov (United States)

    Okubo, Takafumi; Tsukamoto, Takahiro; Suda, Yoshiyuki

    2014-03-01

    We demonstrated a planar electron-tunneling Si/Si0.7Ge0.3 triple-barrier (TB) resonant tunneling diode (RTD) formed via a channel layer on an undoped strain-relaxed quadruple-Si1-xGex-layer (QL) buffer. Compared with a conventional vertical Si/Si0.7Ge0.3 TB RTD formed on a heavily doped QL buffer, the dislocation density is low, the surface is flat, and the resonance current density is much larger. These observations, together with analyses of current-voltage (I-V) curve fitting to the physics-based analytical expression, suggest that the enhanced I-V characteristics in the planar RTD are related to decreases in the number of crystalline defect states and the structural and potential fluctuations.

  16. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    CERN Document Server

    Mosset, J -B; Greuter, U; Hildebrandt, M; Schlumpf, N

    2015-01-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC^4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC^4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  17. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    Science.gov (United States)

    Mosset, J.-B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  18. Passage of Magnetic Tat-Conjugated Fe3O4@SiO2 Nanoparticles Across In Vitro Blood-Brain Barrier

    Science.gov (United States)

    Zhao, Xueqin; Shang, Ting; Zhang, Xiaodan; Ye, Ting; Wang, Dajin; Rei, Lei

    2016-10-01

    Delivery of diagnostic or therapeutic agents across the blood-brain barrier (BBB) remains a major challenge of brain disease treatment. Magnetic nanoparticles are actively being developed as drug carriers due to magnetic targeting and subsequently reduced off-target effects. In this paper, we developed a magnetic SiO2@Fe3O4 nanoparticle-based carrier bound to cell-penetrating peptide Tat (SiO2@Fe3O4 -Tat) and studied its fates in accessing BBB. SiO2@Fe3O4-Tat nanoparticles (NPs) exhibited suitable magnetism and good biocompatibility. NPs adding to the apical chamber of in vitro BBB model were found in the U251 glioma cells co-cultured at the bottom of the Transwell, indicating that particles passed through the barrier and taken up by glioma cells. Moreover, the synergistic effects of Tat and magnetic field could promote the efficient cellular internalization and the permeability across the barrier. Besides, functionalization with Tat peptide allowed particles to locate into the nucleus of U251 cells than the non-conjugated NPs. These results suggest that SiO2@Fe3O4-Tat NPs could penetrate the BBB through the transcytosis of brain endothelial cells and magnetically mediated dragging. Therefore, SiO2@Fe3O4-Tat NPs could be exploited as a potential drug delivery system for chemotherapy and gene therapy of brain disease.

  19. Evaluation of a 256 x 256 Si:As IBC detector array for astronomy

    Science.gov (United States)

    Mckelvey, M. E.; Mcmurray, Robert E., Jr.; Mccreight, C. R.; Forrest, W. J.; Garnett, J. D.; Lum, N.; Asbrock, J.; White, R.; Kelchner, R.; Lum, L.

    1994-01-01

    256 x 256-element IBC Si:As arrays have been evaluated for applications in IR astronomy from space-borne platforms. Basic figures of merit were measured at IR flux levels simulating those expected in space-based astronomical observations. Results include dark current less than 20 e(-)/s, G-eta as high as 3.8, eta/beta of 20%, and read noise below 100 rms(e(-)).

  20. SiC Schottky Diode Detectors for Measurement of Actinide Concentrations from Alpha Activities in Molten Salt Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Windl, Wolfgang [The Ohio State Univ., Columbus, OH (United States); Blue, Thomas [The Ohio State Univ., Columbus, OH (United States)

    2013-01-28

    In this project, we have designed a 4H-SiC Schottky diode detector device in order to monitor actinide concentrations in extreme environments, such as present in pyroprocessing of spent fuel. For the first time, we have demonstrated high temperature operation of such a device up to 500 °C in successfully detecting alpha particles. We have used Am-241 as an alpha source for our laboratory experiments. Along with the experiments, we have developed a multiscale model to study the phenomena controlling the device behavior and to be able to predict the device performance. Our multiscale model consists of ab initio modeling to understand defect energetics and their effect on electronic structure and carrier mobility in the material. Further, we have developed the basis for a damage evolution model incorporating the outputs from ab initio model in order to predict respective defect concentrations in the device material. Finally, a fully equipped TCAD-based device model has been developed to study the phenomena controlling the device behavior. Using this model, we have proven our concept that the detector is capable of performing alpha detection in a salt bath with the mixtures of actinides present in a pyroprocessing environment.

  1. Current Status of High Performance Large Format Si:As IBC Detectors for SOFIA-like Applications

    Science.gov (United States)

    Ennico, Kimberly; Greene, Thomas; McCreight, Craig; McKelvey, Mark; McMurray, Robert, Jr.; Cripe, Jerry; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Airborne and space telescope astronomical observations in the 5-25 micrometer wavelength region, are critical for understanding the physical conditions, composition, chemistry, and excitation of many environments in the interstellar medium, external galaxies, solar system objects, extra-solar systems, and stars. The scientific impact is particularly unique in the 5-8 micrometer and 14-25 micrometer regions which are inaccessible or poorly observed from ground-based observatories. Large-format area mid-infrared (MIR) detectors sensitive over these wavelengths and operable under moderate backgrounds (greater than 10(circumflex)6 e-/s at R=2000, 10(micrometers)) are essential for efficient large-area survey imaging and for taking moderate resolution spectra over a large spectral range. Both SOFIA and passively cooled Explorer observatories could benefit from this technology. Current first-light SOFIA instruments use small-format MIR FPA's of sizes 128x128 and 256x256, With the collaboration of Raytheon Infrared Operations (RIO), NASA-ARC has been testing the first device of this kind, a combination of 1) the ALADDIN III readout multiplexer, cryo-processed for 6K operation, with 2) SIRTF IRAC-like Sides IBC detector material. designed for higher QE and low dark current. Here we report requirements. design, and initial fabrication and testing of the first 1024x1024 Si:As IBC mid-IR detector array for these conditions. This device has exhibited low dark current, moderate noise levels, and greater than 200,000 electron linear well size at 6K operation. We conclude with suggestions for future device development for optimal performance under moderate background, SOFIA- and low Earth orbit observing conditions.

  2. Development of a front-end analog circuit for multi-channel SiPM readout and performance verification for various PET detector designs

    International Nuclear Information System (INIS)

    Silicon photomultipliers (SiPMs) are outstanding photosensors for the development of compact imaging devices and hybrid imaging systems such as positron emission tomography (PET)/ magnetic resonance (MR) scanners because of their small size and MR compatibility. The wide use of this sensor for various types of scintillation detector modules is being accelerated by recent developments in tileable multichannel SiPM arrays. In this work, we present the development of a front-end readout module for multi-channel SiPMs. This readout module is easily extendable to yield a wider detection area by the use of a resistive charge division network (RCN). We applied this readout module to various PET detectors designed for use in small animal PET/MR, optical fiber PET/MR, and double layer depth of interaction (DOI) PET. The basic characteristics of these detector modules were also investigated. The results demonstrate that the PET block detectors developed using the readout module and tileable multi-channel SiPMs had reasonable performance

  3. Development of a front-end analog circuit for multi-channel SiPM readout and performance verification for various PET detector designs

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Guen Bae; Yoon, Hyun Suk [Department of Nuclear Medicine, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Kwon, Sun Il [Department of Nuclear Medicine, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Interdisciplinary Program in Radiation Applied Life Science, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Lee, Chan Mi [Department of Nuclear Medicine, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Department of Biomedical Sciences, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Ito, Mikiko [Department of Nuclear Medicine, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongro-gu, Seoul 110-799 (Korea, Republic of); Hong, Seong Jong [Department of Radiological Science, Eulji University, 212 Yangji-dong, Sujeong-gu, Seongnam-si, Gyeonggi-do, 461-713 (Korea, Republic of); and others

    2013-03-01

    Silicon photomultipliers (SiPMs) are outstanding photosensors for the development of compact imaging devices and hybrid imaging systems such as positron emission tomography (PET)/ magnetic resonance (MR) scanners because of their small size and MR compatibility. The wide use of this sensor for various types of scintillation detector modules is being accelerated by recent developments in tileable multichannel SiPM arrays. In this work, we present the development of a front-end readout module for multi-channel SiPMs. This readout module is easily extendable to yield a wider detection area by the use of a resistive charge division network (RCN). We applied this readout module to various PET detectors designed for use in small animal PET/MR, optical fiber PET/MR, and double layer depth of interaction (DOI) PET. The basic characteristics of these detector modules were also investigated. The results demonstrate that the PET block detectors developed using the readout module and tileable multi-channel SiPMs had reasonable performance.

  4. Comparative study of <111> and <100> crystals and capacitance measurements on Si strip detectors in CMS

    CERN Document Server

    Albergo, S; Azzi, P; Babucci, E; Bacchetta, N; Bader, A J; Bagliesi, G; Basti, A; Biggeri, U; Bilei, G M; Bisello, D; Boemi, D; Bosi, F; Borrello, L; Bozzi, C; Braibant, S; Breuker, Horst; Bruzzi, Mara; Buffini, A; Busoni, S; Candelori, A; Caner, A; Castaldi, R; Castro, A; Catacchini, E; Checcucci, B; Ciampolini, P; Civinini, C; Creanza, D; D'Alessandro, R; Da Rold, M; Demaria, N; De Palma, M; Dell'Orso, R; Marina, R D; Dutta, S; Eklund, C; Peisert, Anna; Feld, L; Fiore, L; Focardi, E; French, M; Freudenreich, Klaus; Fürtjes, A; Giassi, A; Giorgi, M A; Giraldo, A; Glessing, B; Gu, W H; Hall, G; Hammarström, R; Hebbeker, T; Hrubec, Josef; Huhtinen, M; Kaminski, A; Karimäki, V; Saint-Koenig, M; Krammer, Manfred; Lariccia, P; Lenzi, M; Loreti, M; Lübelsmeyer, K; Lustermann, W; Mättig, P; Maggi, G; Mannelli, M; Mantovani, G C; Marchioro, A; Mariotti, C; Martignon, G; McEvoy, B; Meschini, M; Messineo, A; Migliore, E; My, S; Paccagnella, A; Palla, Fabrizio; Pandoulas, D; Papi, A; Parrini, G; Passeri, D; Pieri, M; Piperov, S; Potenza, R; Raducci, V; Raffaelli, F; Raymond, M; Santocchia, A; Schmitt, B; Selvaggi, G; Servoli, L; Sguazzoni, G; Siedling, R; Silvestris, L; Skog, K; Starodumov, Andrei; Stavitski, I; Stefanini, G; Tempesta, P; Tonelli, G; Tricomi, A; Tuuva, T; Vannini, C; Verdini, P G; Viertel, Gert M; Xie, Z; Li Ya Hong; Watts, S; Wittmer, B

    1999-01-01

    For the construction of the silicon microstrip detectors for the tracker of the CMS experiment, two different substrate choices were investigated: A high-resistivity (6 k Omega cm) substrate with crystal orientation and a low-resistivity (2 k Omega cm) one with crystal orientation. The interstrip and backplane capacitances were measured before and after the exposure to radiation in a range of strip pitches from 60 mu m to 240 mu m and for values of the width-over-pitch ratio between 0.1 and 0.5. (3 refs).

  5. Emission reduction in SI engine using ethanol – gasoline blends on thermal barrier coated pistons

    Directory of Open Access Journals (Sweden)

    C.Ananda Srinivasan and C.G.Saravanan

    2010-07-01

    Full Text Available In this study, the effects of ethanol and unleaded gasoline with Isoheptanol blends on multi- cylinder SI engine were investigated. The test fuels were prepared using 99.9% pure ethanol and unleaded gasoline with Isoheptanol blend, in the ratio of E 60 + 2.0 Isoheptanol, E 50 + 1.0 Isoheptanol. In this work the performance, emission and combustion tests were conducted in multi-cylinder petrol engine. The experimental results reveal an increase in brake thermal efficiency on the use of test fuel. In the emission test, CO is found slightly decreased, while HC increased moderately and CO2 and NOx are appreciably reduced, when compared to the sole fuel. The second part of the investigation is carried out in the same engine with Alumina Titania coated crown of the pistons, to gain more inside improvement of engine performance and in-cylinder pressure for coated pistons. The experiment is repeated along with fuel additives and ethanol blends in the same blended ratio to analyse the performance and combustion characteristics of the engine. The results show marginal increase in brake thermal efficiency and reduction in CO, NOx, HC and CO2 emissions. In this study, combustion analyses are made with the help of AVL combustion analyzer, in which cylinder pressure, heat release rate and cumulative heat release are performed.

  6. Prototype Si microstrip sensors for the CDF-II ISL detector

    CERN Document Server

    Hara, K; Kanao, K; Kim, S; Ogasawara, M; Ohsugi, T; Shimojima, M; Takikawa, K

    1999-01-01

    Prototype Si microstrip sensors for the CDF-II ISL were fabricated by Hamamatsu Photonics and SEIKO Instruments using 4'' technology. The sensor is AC coupled and double-sided forming a stereo angle of 1.207 degree sign . The strip pitch is 112 mu m on both sides. The main differences between the two manufacturers lie on the technologies of passivation and the structure of coupling capacitors. We describe the design of the sensor and evaluation results of the performance. The evaluations include the total and individual strip currents and interstrip capacitance measured before and after sup 6 sup 0 Co gamma irradiation. (author)

  7. In-situ fabrication of MoSi2/SiC–Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature

    International Nuclear Information System (INIS)

    MoSi2/SiC–Mo2C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo2C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi2/SiC layer on the upper part of Mo2C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo2C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi2/SiC composite layer.

  8. In-situ fabrication of MoSi2/SiC-Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature

    Science.gov (United States)

    Liu, Jun; Gong, Qianming; Shao, Yang; Zhuang, Daming; Liang, Ji

    2014-07-01

    MoSi2/SiC-Mo2C gradient coating on molybdenum was in situ prepared with pack cementation process by two steps: (1) carburizing with graphite powder to obtain a Mo2C layer on Mo substrate, and (2) siliconizing with Si powder to get a composite MoSi2/SiC layer on the upper part of Mo2C layer. The microstructure and elemental distribution in the coating were investigated with scanning electron microscopy (SEM), back scattered electron (BSE), energy dispersive spectroscopy (EDS), electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Cyclic oxidation tests (at 500 °C, 1200 °C, 1400 °C and 1600 °C) demonstrated excellent oxidation resistance for the gradient composite coating and the mass loss was only 0.23% in 60 min at 1600 °C. XRD, EPMA, thermal dynamic and phase diagram analyses indicated that the Mo2C barrier layer played the key role in slowing down the diffusion of C and Si toward inner Mo substrate at high temperature and principally this contributed to the excellent anti-oxidation for Mo besides the outer MoSi2/SiC composite layer.

  9. Amorphous silicon/crystalline silicon heterojunctions for nuclear radiation detector applications

    International Nuclear Information System (INIS)

    Results on characterization of electrical properties of amorphous Si films for the 3 different growth methods (RF sputtering, PECVD [plasma enhanced], LPCVD [low pressure]) are reported. Performance of these a-Si films as heterojunctions on high resistivity p-type and n- type crystalline Si is examined by measuring the noise, leakage current, and the alpha particle response of 5mm dia detector structures. It is demonstrated that heterojunction detectors formed by RF sputtered films and PECVD films are comparable in performance with conventional surface barrier detectors. Results indicate that the a-Si/c-Si heterojunctions have the potential to greatly simplify detector fabrication. Directions for future avenues of nuclear particle detector development are indicated

  10. Comparative study of LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P TL detectors

    International Nuclear Information System (INIS)

    Recently, two new types of 'tissue equivalent' thermoluminescent detectors (TLDs) have aroused attention: LiF:Mg,Cu,Na,Si and Li2B4O7:Cu,Ag,P. In this work the characteristics of both detectors were compared with the characteristics of the well-known type LiF:Mg,Ti detector, TLD-100. The following properties were investigated: The glow curve structures, relative sensitivity, batch homogeneity and uniformity, detection threshold, reproducibility of the response, linearity in the wide dose range and fading. Also, the energy dependence for medium and low energy X-rays was determined in the range of mean energies between 33 and 116 keV. The results confirmed 'tissue equivalency' of both new types in the investigated range of photon energies. LiF:Mg,Cu,Na,Si detector has very high sensitivity (∼75 times higher than that of TLD-100) and is convenient for use in a very low range of doses. Li2B4O7:Cu,Ag,P detector shows some improvements in comparison with the previously prepared types of lithium borate. The most important is the five times higher sensitivity than that of TLD-100. This detector is also very promising, especially in medical dosimetry. (authors)

  11. Effect of MgZnO barrier layer on the UV emission of n-ZnO/p-Si heterojunction diodes

    International Nuclear Information System (INIS)

    ZnO-based heterojunction light emitting diodes (LEDs) with MgZnO barrier layer had been fabricated on the p-Si substrate by metal-organic chemical vapor deposition (MOCVD) technology. The current-voltage (I-V) characteristics exhibited a typical p-n diode behavior. Both ultraviolet (UV) and visible emissions could be detected in the electroluminescence (EL) measurement. The result was compared with the EL spectrum of n-ZnO/p-Si heterojunction LED without MgZnO barrier layer. An improved light extraction efficiency by about 31% was realized owing to the current-blocking effect of MgZnO layer. The result indicated that MgZnO barrier layer can prevent the electrons as expected and realize electron-hole recombination in ZnO layer effectively. - Highlights: → MgZnO is firstly used as the current-blocking layer in ZnO/Si structures. → Inserting MgZnO layer could improve the quality of the upper ZnO layer. → Under forward bias, prominent UV emission around 388 nm is observed. → We obtain a higher output power than n-ZnO/p-Si structure by almost 31%.

  12. High Performance P-Channel Schottky Barrier MOSFETs with Self-Aligned PtSi Source/Drain on Thin Film SOI Substrate

    Institute of Scientific and Technical Information of China (English)

    ZHU Shi-Yang; LI Ming-Fu

    2005-01-01

    @@ P-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with PtSi Schottky barrier source/drain, high-k gate dielectric and metal gate electrode were fabricated on a thin p-type silicon-on-insulator (SOI) substrateusing a simplified low temperature process. The device works on a fully-depleted accumulation-mode and hasan excellent electrical performance. It reaches Ion/Ioff ratio of about 107, subthreshold swing of 65mV/decade and saturation drain current of Ids= 8.8μA/μm at |Vg - Vth| = |Vd| = 1 V for devices with the channel length 4.0μm and the equivalent oxide thickness 2.0nm. Compared to the corresponding bulk-Si counterparts, SOI p-SBMOSFETs have smaller off-state current due to reduction of the PtSi/Si contact area.

  13. Processing of n+/p-/p+ strip detectors with atomic layer deposition (ALD) grown Al2O3 field insulator on magnetic Czochralski silicon (MCz-si) substrates

    Science.gov (United States)

    Härkönen, J.; Tuovinen, E.; Luukka, P.; Gädda, A.; Mäenpää, T.; Tuominen, E.; Arsenovich, T.; Junkes, A.; Wu, X.; Li, Z.

    2016-08-01

    Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics experiments for particle tracking. In p-type (n+ segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO2 interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al2O3) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current-voltage and capacitance-voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200 GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×1015 neq/cm2 proton irradiated detector the CCE was 35%, when the sensor was biased at 500 V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.

  14. Characterisation of SiC photo-detectors for solar UV radiation monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Borchi, E.; Macii, R. [Fondazione Osservatorio Ximeniano, Via Borgo San Lorenzo, 26-50123 Firenze (Italy); Bruzzi, M. [INFN Firenze and Dipartimento di Energetica, Via S. Marta 3-50139 Firenze (Italy); Scaringella, M., E-mail: Scaringella@fi.infn.it [INFN Firenze and Dipartimento di Energetica, Via S. Marta 3-50139 Firenze (Italy)

    2011-12-01

    Silicon carbide has a potential for solar UV radiation monitoring: extremely resistant to UV radiation damage, nearly-blind to visible and infrared radiation and less sensitive to temperature variations than standard radiometric systems. A radiometer composed by three SiC photodiodes has been designed, manufactured and tested under solar radiation. Two photodiodes are equipped with filters in the UVB (280-315 nm) and UVA (315-400 nm) ranges while a third is filtered to match the erythemal action spectrum. UVA, UVB components of the solar radiation as well as UV index (UVI) at the earth's surface have been determined in two site positions in Tuscany, Italy. Data as a function of day-light allowed us to evaluate total optical thickness for UVA and UVB: {tau}{sub UVA}=0.46 and {tau}{sub UVB}=1.8. UVI values measured during the year well compares with computed ones used for weather forecast procedures.

  15. Effects of high-energy ionizing particles on the Si:As mid-infrared detector array on board the AKARI satellite

    CERN Document Server

    Mouri, Akio; Ishihara, Daisuke; Oyabu, Shinki; Yamagishi, Mituyoshi; Mori, Tatuya; Onaka, Takashi; Wada, Takehiko; Kataza, Hirokazu

    2011-01-01

    We evaluate the effects of high-energy ionizing particles on the Si:As impurity band conduction (IBC) mid-infrared detector on board AKARI, the Japanese infrared astronomical satellite. IBC-type detectors are known to be little influenced by ionizing radiation. However we find that the detector is significantly affected by in-orbit ionizing radiation even after spikes induced by ionizing particles are removed. The effects are described as changes mostly in the offset of detector output, but not in the gain. We conclude that the changes in the offset are caused mainly by increase in dark current. We establish a method to correct these ionizing radiation effects. The method is essential to improve the quality and to increase the sky coverage of the AKARI mid-infrared all-sky-survey map.

  16. Estimation of power dissipation of a 4H-SiC Schottky barrier diode with a linearly graded doping profile in the drift region

    Directory of Open Access Journals (Sweden)

    Rajneesh Talwar

    2009-09-01

    Full Text Available The aim of this paper is to establish the importance of a linearly graded profile in the drift region of a 4H-SiC Schottky barrier diode (SBD. The power dissipation of the device is found to be considerably lower at any given current density as compared to its value obtained for a uniformly doped drift region. The corresponding values of breakdown voltages obtained are similar to those obtained with uniformly doped wafers of 4H-SiC.

  17. Nanoparticle mediated P-glycoprotein silencing for improved drug delivery across the blood-brain barrier: a siRNA-chitosan approach.

    Directory of Open Access Journals (Sweden)

    Jostein Malmo

    Full Text Available The blood-brain barrier (BBB, composed of tightly organized endothelial cells, limits the availability of drugs to therapeutic targets in the central nervous system. The barrier is maintained by membrane bound efflux pumps efficiently transporting specific xenobiotics back into the blood. The efflux pump P-glycoprotein (P-gp, expressed at high levels in brain endothelial cells, has several drug substrates. Consequently, siRNA mediated silencing of the P-gp gene is one possible strategy how to improve the delivery of drugs to the brain. Herein, we investigated the potential of siRNA-chitosan nanoparticles in silencing P-gp in a BBB model. We show that the transfection of rat brain endothelial cells mediated effective knockdown of P-gp with subsequent decrease in P-gp substrate efflux. This resulted in increased cellular delivery and efficacy of the model drug doxorubicin.

  18. The MINDView brain PET detector, feasibility study based on SiPM arrays

    Science.gov (United States)

    González, Antonio J.; Majewski, Stan; Sánchez, Filomeno; Aussenhofer, Sebastian; Aguilar, Albert; Conde, Pablo; Hernández, Liczandro; Vidal, Luis F.; Pani, Roberto; Bettiol, Marco; Fabbri, Andrea; Bert, Julien; Visvikis, Dimitris; Jackson, Carl; Murphy, John; O'Neill, Kevin; Benlloch, Jose M.

    2016-05-01

    The Multimodal Imaging of Neurological Disorders (MINDView) project aims to develop a dedicated brain Positron Emission Tomography (PET) scanner with sufficient resolution and sensitivity to visualize neurotransmitter pathways and their disruptions in mental disorders for diagnosis and follow-up treatment. The PET system should be compact and fully compatible with a Magnetic Resonance Imaging (MRI) device in order to allow its operation as a PET brain insert in a hybrid imaging setup with most MRI scanners. The proposed design will enable the currently-installed MRI base to be easily upgraded to PET/MRI systems. The current design for the PET insert consists of a 3-ring configuration with 20 modules per ring and an axial field of view of ~15 cm and a geometrical aperture of ~33 cm in diameter. When coupled to the new head Radio Frequency (RF) coil, the inner usable diameter of the complete PET-RF coil insert is reduced to 26 cm. Two scintillator configurations have been tested, namely a 3-layer staggered array of LYSO with 1.5 mm pixel size, with 35×35 elements (6 mm thickness each) and a black-painted monolithic LYSO block also covering about 50×50 mm2 active area with 20 mm thickness. Laboratory test results associated with the current MINDView PET module concept are presented in terms of key parameters' optimization, such as spatial and energy resolution, sensitivity and Depth of Interaction (DOI) capability. It was possible to resolve all pixel elements from the three scintillator layers with energy resolutions as good as 10%. The monolithic scintillator showed average detector resolutions varying from 3.5 mm in the entrance layer to better than 1.5 mm near the photosensor, with average energy resolutions of about 17%.

  19. Application of a double-sided silicon-strip detector as a differential pumping barrier for NESR experiments at FAIR

    International Nuclear Information System (INIS)

    The presented work focuses on the development of a differential pumping system using double-sided silicon-strip detectors to separate the ultra-high vacuum of a storage ring from subsequent detectors and outgassing components placed in an auxiliary vacuum. Such a technical concept will give the opportunity to use telescope-like detector systems in an ultra-high vacuum environment, such as a storage ring, without enclosing the entire system in a pocket. Therefore, it will enable the detection of recoil particles with the smallest possible energy due to the use of the innermost strip detector as an active window. Our results prove that such an assembly is feasible without having an effect, within experimental errors, on the performance of the strip detector. Vacuum separation better than six orders of magnitude was achieved with the ultra-high vacuum side reaching down to the 10-10mbar pressure region.

  20. Energy-dispersive X-ray fluorescence of discarded tire samples, using a Si-PIN detector

    International Nuclear Information System (INIS)

    The determination of zinc concentration in samples of discarded tires is of great environmental interest because the process for manufacturing tyres uses S for rubber vulcanization, and ZnO is the reaction catalyst. Discarded tyres are being used in asphalt paving, in the burning process of thermoelectric and cement industries and also for controlling erosion in agricultural areas. Analysis of tyre samples usually requires chemical digestion which is slow and expensive. Aiming to eliminate those limitations, this work uses energy-dispersive X-ray fluorescence (EDXRF) with a portable equipment, once it is a simultaneous multi-element analytical technique, requiring minimal sample preparation. Five samples of discarded tyres have been ground and analysed in the form of pastilles, using a mini X-ray tube (Ag target, MO filter, 25 kV/20 μA) for 200 s, and a Si-PIN semiconductor detector coupled to a multichannel analyser. Zinc concentrations in the range of 40.6 to 44.2 μg g-1 have been obtained, representing 0.4% of the tire composition, which is below the maximum value (2%) recommended by the European Tyre Recycling Association. Concentrations between 0.15 and 0.52 μg g-1 were obtained for Fe

  1. Improving the gas barrier and mechanical properties of a-SiO x films synthesized at low temperature by using high energy and hydrogen flow rate control

    Science.gov (United States)

    Jin, Su B.; Long, Wen; Sahu, B. B.; Han, Jeon G.; Hori, M.

    2015-05-01

    Silicon-oxide thin films were deposited on polyethylene-terephthalate (PET) and glass substrates for applications in transparent barrier packaging and replacement display cover glasses by using plasma-enhanced chemical vapor deposition (PECVD). The bias conditions and the input power in the radio-frequency plasma were changed to optimize the gas barrier and the mechanical properties of the silicon-oxide thin film. We made an advanced plasma source for large-area PECVD (370 × 470 mm2 size). The dissociation of the octamethylycyclodisiloxane (OMCTS) precursor was controlled by using the plasma processing parameters. The gas barrier and the mechanical properties of the a-SiO x film were improved by controlling the plasma process parameters. The gas barrier and the mechanical properties of the coatings were examined using a Permatran (MOCON) system and a pencil hardness measurement. The chemical structure properties of the coatings were examined by using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The properties of the a-SiO x thin films were improved by the dissociation of OMCTS obtained by using various appropriate plasma processing parameters.

  2. Effects of deposition conditions on gas-barrier performance of SiOxNy thin films formed via ion-beam-assisted vapor deposition

    International Nuclear Information System (INIS)

    SiOxNy thin films were synthesized via ion-beam-assisted vapor deposition (IVD) where deposition of SiOx was irradiated by nitrogen ions. Firstly, reasonable-cost evaporation materials showing less splashing for the SiOx films were investigated by selecting appropriate sintering condition regimes of Si and SiO2 mixed powders. The SiOxNy thin films on a polyethylene terephtalate film substrate obtained via IVD showed a low oxygen transmission rate (OTR) of less than 1 cm3/m2 day. Effective nitrogen ion irradiation energy per atom was 8 eV/at. or greater, which is consistent with regimes where densification of thin films is reported to occur. Higher N2 partial pressure yielded a lower OTR and a higher nitrogen atomic ratio of the films obtained. It is suggested that the improvement in gas-barrier performance resulted from densification and chemical change of the films due to energy addition and nitrification produced by nitrogen ion-beam irradiation

  3. Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

    Science.gov (United States)

    Omotoso, E.; Meyer, W. E.; Auret, F. D.; Diale, M.; Ngoepe, P. N. M.

    2016-01-01

    Irradiation experiments have been carried out on 1.9×1016 cm-3 nitrogen-doped 4H-SiC at room temperature using 5.4 MeV alpha-particle irradiation over a fluence ranges from 2.6×1010 to 9.2×1011 cm-2. Current-voltage (I-V), capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements have been carried out to study the change in characteristics of the devices and free carrier removal rate due to alpha-particle irradiation, respectively. As radiation fluence increases, the ideality factors increased from 1.20 to 1.85 but the Schottky barrier height (SBHI-V) decreased from 1.47 to 1.34 eV. Free carrier concentration, Nd decreased with increasing fluence from 1.7×1016 to 1.1×1016 cm-2 at approximately 0.70 μm depth. The reduction in Nd shows that defects were induced during the irradiation and have effect on compensating the free carrier. The free carrier removal rate was estimated to be 6480±70 cm-1. Alpha-particle irradiation introduced two electron traps (E0.39 and E0.62), with activation energies of 0.39±0.03 eV and 0.62±0.08 eV, respectively. The E0.39 as attribute related to silicon or carbon vacancy, while the E0.62 has the attribute of Z1/Z2.

  4. Analysis of the effect of sidewall on the performance of 6H-SiC Schottky barrier source/drain NMOSFETs

    Institute of Scientific and Technical Information of China (English)

    Tang Xiao-Yan; Zhang Yi-Men; Zhang Yu-Ming; Gao Jin-Xia

    2004-01-01

    Between source/drain and gate of SiC Schottky barrier source/drain MOSFET (SiC SBSD-MOSFET), there must be a sidewall as isolation. The width of sidewall strongly affects on the device performance. In this paper the effect of sidewall on the performance of 6H-SiC SBSD-NMOSFET is simulated with the 2D simulator MEDICI. The simulated results show that a sidewall with width less than 0.1μm slightly affects the device performance. However, when the width of sidewall exceeds 0.1μm, the conduction does not occur until the drain voltage is high enough and saturation current sharply decreases. The effect of the sidewall on device performance can be reduced by decreasing the doping concentration in the epitaxial layer.

  5. Dimensionless parameterization of lidar for laser remote sensing of the atmosphere and its application to systems with SiPM and PMT detectors

    OpenAIRE

    Agishev, Ravil R.; Comerón Tejero, Adolfo; Rodríguez Gómez, Alejandro Antonio; Sicard, Michaël

    2014-01-01

    In this paper, we show a renewed approach to the generalized methodology for atmospheric lidar assessment, which uses the dimensionless parameterization as a core component. It is based on a series of our previous works where the problem of universal parameterization over many lidar technologies were described and analyzed from different points of view. The modernized dimensionless parameterization concept applied to relatively new silicon photomultiplier detectors (SiPMs) and traditional pho...

  6. Improved performance of GaN metal-semiconductor-metal ultraviolet detectors by depositing SiO2 nanoparticles on a GaN surface

    Science.gov (United States)

    Sun, Xiaojuan; Li, Dabing; Jiang, Hong; Li, Zhiming; Song, Hang; Chen, Yiren; Miao, Guoqing

    2011-03-01

    GaN metal-semiconductor-metal (MSM) ultraviolet detectors were investigated by depositing different density of SiO2 nanoparticles (SNPs) on the GaN. It was shown that the dark current of the detectors with SNPs was more than one order of magnitude lower than that without SNPs and the peak responsivity was enhanced after deposition of the SNPs. Atomic force microscopy observations indicated that the SNPs usually formed at the termination of screw and mixed dislocations, and further current-voltage measurements showed that the leakage of the Schottky contact for the GaN MSM detector decreased with deposited the SNPs. Moreover, the leakage obeyed the Frenkel-Poole emission model, which meant that the mechanism for improving the performance is the SNPs passivation of the dislocations followed by the reduction in the dark current.

  7. Comparative Measurements of the Photon Detection Efficiency of KETEK SiPM Detectors for the LHCb SciFi Upgrade Project

    CERN Document Server

    Joram, Christian

    2014-01-01

    The LHCb SciFi detector is conceived to employ arrays of SiPM detectors to detect scintillation light from ribbons of 2.5 m long scintillating fibres of 250 $\\mu$m diameter. The fibres of type Kuraray SCSF-78 are blue emitting with an emission maximum at 440 nm. However, as a consequence of the radiation damage mainly from charged hadrons in the LHCb experiments, the effective emission spectrum at the end of the fibre will shift to longer wavelengths. A simulation of the light absorption in the fibre, assuming an ionizing dose distribution along the fibre as predicted by the FLUKA code, is able to predict the emission spectrum. Fig. 1 shows the emission spectra (in arbitrary units) for 10 cm intervals along the fibre. At 250 cm, where the ionization dose is expected to reach over the full lifetime of the upgrade LHCb detector about 30 kGy, the average wavelength of emission is approximately 500 nm. The sensitivity spectrum of the SiPM detector should be tuned to match this emission spectrum, i.e. the PDE shou...

  8. The Development of Environmental Barrier Coating Systems for SiC-SiC Ceramic Matrix Composites: Environment Effects on the Creep and Fatigue Resistance

    Science.gov (United States)

    Zhu, Dongming; Ghosn, Louis J.

    2014-01-01

    Topics covered include: Environmental barrier coating system development: needs, challenges and limitations; Advanced environmental barrier coating systems (EBCs) for CMC airfoils and combustors; NASA EBC systems and material system evolutions, Current turbine and combustor EBC coating emphases, Advanced development, processing, testing and modeling, EBC and EBC bond coats: recent advances; Design tool and life prediction of coated CMC components; Advanced CMC-EBC rig demonstrations; Summary and future directions.

  9. Infrared detectors and focal plane arrays II; Proceedings of the Meeting, Orlando, FL, Apr. 23, 24, 1992

    Science.gov (United States)

    Dereniak, Eustace L.; Sampson, Robert E.

    The present conference discusses Schottky-barrier IR image sensors, SWIR and MWIR Schottky-barrier imagers, a 640 x 640 PtSi, models of nonlinearities in focal plane arrays, retinal function relative to IRT focal plane arrays, a solid-state pyroelectric imager, and electrolyte electroreflectance spectroscopies for the ion-implanted HgCdTe with thermal annealing. Also discussed are HgCdTe hybrid focal plane arrays for thermoelectrically cooled applications, a novel IR detector plasma-edge detector, and IR detector circuits using monolithic CMOS amps with InSb detectors. (No individual items are abstracted in this volume)

  10. Response of CR39 detector to 5 A GeV Si14+ ions and measurement of total charge changing cross-section

    International Nuclear Information System (INIS)

    In the present work, response of CR39 track etch detector was obtained by cone-height measurement technique. CR39 track etch detector was used to identify the incident charged particles and their fragments by the measurements of cone-height of tracks using an optical microscope DM6000 M and automated image analyzer system installed with Leica QWin Plus software. The CR39 detector was calibrated and the response points were fitted with a linear relation and all the points are within the limits of the experimental errors. The charge resolution of the detector was calculated to be 0.2e. The response function is obtained and fitted with a linear relation which is good throughout Z/β=6.1–14.1. The experimental value of the total charge changing cross-section of 5 A GeV Si14+ ion beam in polyethylene and CR39 combined target is σtot=(734±128) mb. The total charge changing cross-section is compared with the experimental results of others based on cone base-area measurement technique and also fitted by the Bradt–Peters geometrical cross-section. - Highlights: • Charge resolution of 0.2e was obtained by cone-height measurement. • Consistency in manual measurements of cone-heights is presented. • Response of CR39 detector was obtained and fitted with first degree polynomial. • Total charge changing cross-section of 5 A GeV Si14+ ions in CH2 and CR39 as a combined target was calculated

  11. Investigation of enzyme-sensitive lipid nanoparticles for delivery of siRNA to blood–brain barrier and glioma cells

    DEFF Research Database (Denmark)

    Bruun, Jonas; Larsen, Trine Bjørnbo; Jølck, Rasmus Irming;

    2015-01-01

    Clinical applications of siRNA for treating disorders in the central nervous system require development of systemic stable, safe, and effective delivery vehicles that are able to cross the impermeable blood–brain barrier (BBB). Engineering nanocarriers with low cellular interaction during systemic...... circulation, but with high uptake in targeted cells, is a great challenge and is further complicated by the BBB. As a first step in obtaining such a delivery system, this study aims at designing a lipid nanoparticle (LNP) able to efficiently encapsulate siRNA by a combination of titratable cationic lipids....... The targeted delivery is obtained through the design of a two-stage system where the first step is conjugation of angiopep to the surface of the LNP for targeting the low-density lipoprotein receptor-related protein-1 expressed on the BBB. Second, the positively charged LNPs are masked with a negatively...

  12. Measurement of the top Yukawa Coupling at a 1 TeV International Linear Collider using the SiD detector

    CERN Document Server

    Roloff, Philipp

    2013-01-01

    One of the detector benchmark processes investigated for the SiD Detailed Baseline Design (DBD) is given by: $e^+ e^- \\to t\\bar{t}H$, where H is the Standard Model Higgs boson of mass 125 GeV. The study is carried out at a centre-of-mass energy of 1 TeV and assuming an integrated luminosity of 1 ab$^{-1}$. The physics aim is a direct measurement of the top Yukawa coupling at the ILC. Higgs boson decays to beauty quark-antiquark pairs are reconstructed. The investigated final states contain eight jets or six jets, one charged lepton and missing energy. Additionally, four of the jets in signal events are caused by beauty quark decays. The analysis is based on a full simulation of the SiD detector using GEANT4. Beam-related backgrounds from $\\gamma\\gamma \\to$ hadrons interactions and incoherent $e^+ e^-$ pairs are considered. This study addresses various aspects of the detector performance: jet clustering in complex hadronic final states, flavour-tagging and the identification of high energy leptons.

  13. Quantum well intersubband THz lasers and detectors

    Science.gov (United States)

    Soref, Richard A.; Friedman, Lionel R.; Sun, Gregory; Noble, Michael J.; Ram-Mohan, L. R.

    1999-11-01

    This paper presents modeling and simulation results on Si- based quantum-well intersubband THz detectors and THz lasers (tasers) in the 3 to 10 THz range where the intersubband transition energy is 12 to 41 meV. The incoherent cryogenically cooled (4 K to 20 K) quantum well terahertz detector (QWTD) consists of p-type Si0.9Ge0.1 QWs with Si barriers on an Si substrate, or of p-Si0.85Ge0.15/Si on a relaxed Si0.97Ge0.03 buffer on Si. The QWTD senses THz radiation at normal incidence (the XY polarization on the HH1 to LH1 transition) or at edge- illumination (the Z polarization on the HH1 to HH2 transition). Resonant-cavity enhancement, coupling to Si THz waveguides, and integration with SiGe transistor preamplifiers appear feasible for QWTDs. The quantum staircase taser is a simplified far-infrared version of the quantum cascade laser in which each superlattice transfer region is replaced by a thin tunnel-barrier layer. We have adapted to group IV the III-V idea of Sun, Lu, and Khurgin; the `inverted mass taser'. On a Si0.81Ge0.19 substrate, we find that an inverted effective mass exists in LH1 at kg equals 0.013 angstroms-1 in 9-nm single- wells of Si0.7Ge0.3 with 5-nm Si barriers. Selective electrical injection of holes into LH1 at T equals 77 K is postulated. This offers local-in-k-space LH1-HH1 population inversion and tasing at 7.2 THz. Since the taser emission is XY-polarized, the active MQW staircase (a set of identical square QWs) is suitable for insertion into a vertical cavity surface-emitting taser. The VCSET would have resonator thickness of (lambda) /2n equals 6 micrometers , and Bragg mirrors constructed from SiO2/Si multilayers.

  14. Failure behavior of ITO diffusion barrier between electroplating Cu and Si substrate annealed in a low vacuum

    International Nuclear Information System (INIS)

    A structure of Cu/ITO(10 nm)/Si was first formed and then annealed at various temperatures for 5 min in a rapid thermal annealing furnace under 10-2 Torr pressure. In Cu/ITO(10 nm)/Si structure, the ITO(10 nm) film was coated on Si substrate by sputtering process and the Cu film was deposited on ITO film by electroplating technique. The various Cu/ITO(10 nm)/Si samples were characterized by a four-point probe, a scanning electron microscope, an X-ray diffractometer, and a transmission electron microscope. The results showed that when the annealing temperature increases near 600 deg. C the interface between Cu and ITO becomes unstable, and the Cu3Si particles begin to form; and when the annealing temperature increases to 650 deg. C, a good many of Cu3Si particles about 1 μm in size form and the sheet resistance of Cu/ITO(10 nm)/Si structure largely increases.

  15. 4$\\pi$ detector for study of Zeno effect using 220Rn -> 216Po alpha->alpha correlated chains

    CERN Document Server

    Nadderd, L; Subotic, K; Polyakov, A N; Lobanov, Y V; Rykhlyuk, A V

    2015-01-01

    First test of the 4pi detector for study of exponential law of radioactive decay and possibility of observation of Zeno effect [1-3], measuring the mean life of 216Po is presented. This detector consists of two surface-barrier n-Si(Au) detectors placed in the close contact ( 4T1/2. Both, the data acquisition system and the vacuum chamber design are presented in brief.

  16. Vapor-phase epitaxial growth of thick single crystal CdTe on Si substrate for X-ray, gamma ray spectroscopic detector development

    Energy Technology Data Exchange (ETDEWEB)

    Niraula, Madan; Yasuda, Kazuhito; Yamashita, Hayate; Wajima, Yuto; Tsukamoto, Yudai; Matsumoto, Masahiko; Suzuki, Yuta; Takai, Noriaki; Tsukamoto, Yuki; Agata, Yasunori [Nagoya Institute of Technology, Graduate School of Engineering, Gokiso, Showa, Nagoya 466-8555 (Japan)

    2014-07-15

    We investigated MOVPE growth conditions to grow large-area and thick single crystal CdTe layers with uniform material properties directly on (211) Si substrates to develop nuclear radiation detectors. We found that group VI/II precursor flow-ratio as well as rapid thermal annealing performed by interrupting the growth at the initial stage has marked influence on the crystal quality. By using a VI/II precursor ratio of 3.0, and a 900 C anneal performed in flowing hydrogen, we were able to achieve 1-sq inch sized thick single crystal CdTe that showed uniform material properties and high crystal quality throughout the wafer. We further demonstrated that the grown crystals were suitable for fabricating nuclear radiation detector. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Infrared detectors: State of art; Proceedings of the Meeting, San Diego, CA, July 23, 24, 1992

    Science.gov (United States)

    Makky, Wagih H.

    1992-12-01

    The present conference discusses innovative IR detection devices and technologies, HgCdTe-based IR detectors, and quantum-well (QW) devices. Attention is given to uncooled thermal imaging, intersubband transitions and IR hot-electron transistors, the consideration of a novel two-color IR detector on the basis of the 'two-peak' effect, recent developments in MOCVD of Hg(1-x)Cd(x)Te photodiode arrays, and the growth of HgCdTe by MBE on CdZnTe substrates. Also discussed are Si-based QW intersubband detectors, increased responsivity and detectivity in asymmetric QW IR detectors, IR internal emission detectors, an InSb monolithic focal-plane cell, and surface plasmons on PtSi for visible and Si Schottky-barrier-enhanced detection. (No individual items are abstracted in this volume)

  18. Highly conformal SiO2/Al2O3 nanolaminate gas-diffusion barriers for large-area flexible electronics applications

    International Nuclear Information System (INIS)

    The present study demonstrates a flexible gas-diffusion barrier film, containing an SiO2/Al2O3 nanolaminate on a plastic substrate. Highly uniform and conformal coatings can be made by alternating the exposure of a flexible polyethersulfone surface to vapors of SiO2 and Al2O3, at nanoscale thickness cycles via RF-magnetron sputtering deposition. The calcium degradation test indicates that 24 cycles of a 10/10 nm inorganic bilayer, top-coated by UV-cured resin, greatly enhance the barrier performance, with a permeation rate of 3.79 x 10-5 g m-2 day-1 based on the change in the ohmic behavior of the calcium sensor at 20 deg. C and 50% relative humidity. Also, the permeation rate for 30 cycles of an 8/8 nm inorganic bilayer coated with UV resin was beyond the limited measurable range of the Ca test at 60 deg. C and 95% relative humidity. It has been found that such laminate films can effectively suppress the void defects of a single inorganic layer, and are significantly less sensitive against moisture permeation. This nanostructure, fabricated by an RF-sputtering process at room temperature, is verified as being useful for highly water-sensitive organic electronics fabricated on plastic substrates.

  19. Effect of SiN x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol-gel dip coating and reactive magnetron sputtering.

    Science.gov (United States)

    Ghazzal, Mohamed Nawfal; Aubry, Eric; Chaoui, Nouari; Robert, Didier

    2015-01-01

    We investigate the effect of the thickness of the silicon nitride (SiN x ) diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol-gel) and physical methods (reactive sputtering) are affected differentially by the intercalating SiN x diffusion barrier. Increasing the thickness of the SiN x diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol-gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiN x barrier diffusion. The SiN x barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed.

  20. Time-of-flight ERD with a 200 mm2 Si3N4 window gas ionization chamber energy detector

    Science.gov (United States)

    Julin, Jaakko; Laitinen, Mikko; Sajavaara, Timo

    2014-08-01

    Low energy heavy ion elastic recoil detection work has been carried out in Jyväskylä since 2009 using home made timing detectors, a silicon energy detector and a timestamping data acquisition setup forming a time-of-flight-energy telescope. In order to improve the mass resolution of the setup a new energy detector was designed to replace the silicon solid state detector, which suffered from radiation damage and had poor resolution for heavy recoils. In this paper the construction and operation of an isobutane filled gas ionization chamber with a 14 × 14 mm2 100 nm thick silicon nitride window are described. In addition to greatly improved energy resolution for heavy ions, the detector is also able to detect hydrogen recoils simultaneously in the energy range of 100-1000 keV. Additionally the detector has position sensitivity by means of timing measurement, which can be performed without compromising the performance of the detector in any other way. The achieved position sensitivity improves the depth resolution near the surface.

  1. SU-C-201-01: Investigation of the Effects of Scintillator Surface Treatment On Light Output Measurements with SiPM Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Valenciaga, Y; Prout, D; Chatziioannou, A [University of California, Los Angeles (UCLA) (United States)

    2015-06-15

    Purpose: To examine the effect of different scintillator surface treatments (BGO crystals) on the fraction of scintillation photons that exit the crystal and reach the photodetector (SiPM). Methods: Positron Emission Tomography is based on the detection of light that exits scintillator crystals, after annihilation photons deposit energy inside these crystals. A considerable fraction of the scintillation light gets trapped or absorbed after going through multiple internal reflections on the interfaces surrounding the crystals. BGO scintillator crystals generate considerably less scintillation light than crystals made of LSO and its variants. Therefore, it is crucial that the small amount of light produced by BGO exits towards the light detector. The surface treatment of scintillator crystals is among the factors affecting the ability of scintillation light to reach the detectors. In this study, we analyze the effect of different crystal surface treatments on the fraction of scintillation light that is detected by the solid state photodetector (SiPM), once energy is deposited inside a BGO crystal. Simulations were performed by a Monte Carlo based software named GATE, and validated by measurements from individual BGO crystals coupled to Philips digital-SiPM sensor (DPC-3200). Results: The results showed an increment in light collection of about 4 percent when only the exit face of the BGO crystal, is unpolished; compared to when all the faces are polished. However, leaving several faces unpolished caused a reduction of at least 10 percent of light output when the interaction occurs as far from the exit face of the crystal as possible compared to when it occurs very close to the exit face. Conclusion: This work demonstrates the advantages on light collection from leaving unpolished the exit face of BGO crystals. The configuration with best light output will be used to obtain flood images from BGO crystal arrays coupled to SiPM sensors.

  2. Osteoconductive Potential of Barrier NanoSiO2 PLGA Membranes Functionalized by Plasma Enhanced Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Antonia Terriza

    2014-01-01

    Full Text Available The possibility of tailoring membrane surfaces with osteoconductive potential, in particular in biodegradable devices, to create modified biomaterials that stimulate osteoblast response should make them more suitable for clinical use, hopefully enhancing bone regeneration. Bioactive inorganic materials, such as silica, have been suggested to improve the bioactivity of synthetic biopolymers. An in vitro study on HOB human osteoblasts was performed to assess biocompatibility and bioactivity of SiO2 functionalized poly(lactide-co-glycolide (PLGA membranes, prior to clinical use. A 15 nm SiO2 layer was deposited by plasma enhanced chemical vapour deposition (PECVD, onto a resorbable PLGA membrane. Samples were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, and infrared spectroscopy (FT-IR. HOB cells were seeded on sterilized test surfaces where cell morphology, spreading, actin cytoskeletal organization, and focal adhesion expression were assessed. As proved by the FT-IR analysis of samples, the deposition by PECVD of the SiO2 onto the PLGA membrane did not alter the composition and other characteristics of the organic membrane. A temporal and spatial reorganization of cytoskeleton and focal adhesions and morphological changes in response to SiO2 nanolayer were identified in our model. The novedous SiO2 deposition method is compatible with the standard sterilization protocols and reveals as a valuable tool to increase bioactivity of resorbable PLGA membranes.

  3. High-contrast X-ray radiography using hybrid semiconductor pixel detectors with 1 mm thick Si sensor as a tool for monitoring liquids in natural building stones

    International Nuclear Information System (INIS)

    For the preservation of buildings and other cultural heritage, the application of various conservation products such as consolidants or water repellents is often used. X-ray radiography utilizing semiconductor particle-counting detectors stands out as a promising tool in research of consolidants inside natural building stones. However, a clear visualization of consolidation products is often accomplished by doping with a contrast agent, which presents a limitation. This approach causes a higher attenuation for X-rays, but also alters the penetration ability of the original consolidation product. In this contribution, we focus on the application of Medipix type detectors newly equipped with a 1 mm thick Si sensor. This thicker sensor has enhanced detection efficiency leading to extraordinary sensitivity for monitoring consolidants and liquids in natural building stones even without any contrast agent. Consequently, methods for the direct monitoring of organosilicon consolidants and dynamic visualization of the water uptake in the Opuka stone using high-contrast X-ray radiography are demonstrated. The presented work demonstrates a significant improvement in the monitoring sensitivity of X-ray radiography in stone consolidation studies and also shows advantages of this detector configuration for X-ray radiography in general

  4. 离子注入型与金硅面垒型半导体探测器温度特性比较%Temperature Characteristic Comparison between Ion-injection and Gold Silicon Surface Barrier Semi-conducting Detectors

    Institute of Scientific and Technical Information of China (English)

    崔晓辉; 谷铁男; 张燕; 袁宝吉; 刘明健; 闫学昆

    2011-01-01

    The performance of semi-conducting detector is sensitive to temperature,which directly affects the stability and precision of spectrum system.A bias-voltage testing circuit,used for temperature characteristic testing was designed firstly,and then the characteristic curve between bias-voltage and temperature,for ion-injection detector and gold silicon surface barrier detector respectively,was ascertained.Experimental results show that the temperature characteristic of an ion-injection detector is much better than that of a gold silicon surface barrier detector.This method is valid for the use and selection of semi-conducting detector.%半导体探测器性能受温度影响较大,影响着辐射探测系统的稳定性和测量精度。本文设计了一个温度测试电路,通过温度测试实验分别得出了离子注入型和金硅面垒型半导体探测器的温度特性曲线。测试结果表明,离子注入型半导体探测器的温度特性明显优于金硅面垒型半导体探测器。本文的结果可为半导体探测器的使用、筛选提供参考。

  5. Normally-Off AlGaN/GaN-on-Si Power Switching Device with Embedded Schottky Barrier Diode

    Science.gov (United States)

    Park, Bong-Ryeol; Lee, Jae-Gil; Cha, Ho-Young

    2013-03-01

    We have demonstrated a novel AlGaN/GaN power switching device with an embedded Schottky barrier diode. The normally-off transistor mode was implemented with a recessed metal-oxide-semiconductor heterostructure field-effect transistor (MOSHFET) configuration in which a Schottky barrier diode (SBD) was embedded to flow the reverse current. The proposed device is very promising for use in high-efficiency converter and inverter ICs. The prototype device exhibited encouraging characteristics: a turn-on voltage of 2 V for the transistor and a forward turn-on voltage of 0.8 V for the embedded diode. The breakdown voltage for the anode-to-cathode distance of 10 µm was 966 V.

  6. The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)

    OpenAIRE

    Watanabe, Shin; Tajima, Hiroyasu; Fukazawa, Yasushi; Ichinohe, Yuto; Takeda, Shin'ichiro; Enoto, Teruaki; Fukuyama, Taro; Furui, Shunya; Genba, Kei; Hagino, Kouichi; Harayama, Astushi; Kuroda, Yoshikatsu; Matsuura, Daisuke; Nakamura, Ryo; Nakazawa, Kazuhiro

    2015-01-01

    The Soft Gamma-ray Detector (SGD) is one of the instrument payloads onboard ASTRO-H, and will cover a wide energy band (60--600 keV) at a background level 10 times better than instruments currently in orbit. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and cadmium telluride (CdTe) sensors. The design of the SGD Compton...

  7. Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

    OpenAIRE

    Karthikeya Sharma, T.

    2014-01-01

    Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include t...

  8. Gamma large area silicon telescope: Applying SI strip detector technology to the detection of gamma rays in space

    Science.gov (United States)

    Atwood, W. B.; Bloom, E. D.; Godfrey, G. L.; Hertz, P. L.; Lin, Ying-Chi; Nolan, P. L.; Snyder, A. E.; Taylor, R. E.; Wood, K. S.; Michelson, P. F.

    1992-12-01

    The recent discoveries and excitement generated by EGRET (Energetic Gamma Ray Experiment Telescope) (presently operating on CGRO (Compton Gamma Ray Observatory)) has prompted an investigation into modern technologies ultimately leading to the next generation space based gamma ray telescope. The goal is to design a detector that would increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays and the triggering capability of the instrument. The proposed GLAST (Gamma Ray Large Area Silicon Telescope) instrument is based on silicon particle detectors that offer the advantages of no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST tracker has planes of cross strip (x, y) 300 micrometer match silicon detectors coupled to a thin radiator to measure the coordinates of converted electron-positron pairs. An angular resolution of 0.1 deg at high energy is possible (the low energy angular resolution 100 MeV would be about 2 deg, limited by multiple scattering). The increased depth of the GLAST calorimeter over EGRET's extends the energy range to about 300 GeV.

  9. NUV/VIS sensitive multicolor thin film detector based on a-SiC:H/a-Si:H/{mu}c-SiGeC:H alloys with an in-situ structured transparent conductive oxide front contact without etching

    Energy Technology Data Exchange (ETDEWEB)

    Bablich, A., E-mail: andreas.bablich@uni-siegen.de; Boehm, M., E-mail: m.boehm@t-online.de

    2012-10-01

    An innovative family of hydrogenated amorphous silicon (a-Si:H) multicolor p-i-n photo sensors, sensitive in the VIS and the near UV spectrum, is presented. Typical values of the quantum efficiency at 350 nm and 580 nm are 5.4% and 54.7%, respectively, with - 0.4 V and - 12 V bias. Electro-optical studies were performed to explore the effect of combining linearly graded a-SiGe:H/{mu}c-SiGeC:H layers with linearly graded a-SiC:H-layers. The devices presented additionally contain a buried a-Si:H region. Low-reflective aluminum doped zinc oxide (ZnO:Al) back contacts improve the spectral color separation. {mu}{tau}-products and absorption coefficients of graded absorbers were determined. Discrete absorbers were substituted by a linear graded a-SiC:H absorption zone in the top structure, an interior a-Si:H region and a graded a-SiGe:H/a-SiC:H alloy combination. In this paper we demonstrate a reduction of interference fringes and operation at low bias voltages, combined with a highly precise adjustment of the spectral sensitivity, even in the near UV-spectrum. The device dynamic range exceeds 50 dB at 1000 lx white-light illumination. As the deposited upper layers adopt the roughness of {mu}c-SiGeC:H clusters in the rear absorber, we present an in-situ structured front contact without etching ZnO:Al. - Highlights: Black-Right-Pointing-Pointer Structuring zinc oxide anode without etching Black-Right-Pointing-Pointer UV/VIS amorphous silicon sensor Black-Right-Pointing-Pointer Microcrystalline narrow gap absorber Black-Right-Pointing-Pointer Significant color separation improvement.

  10. 4.0-nm-thick amorphous Nb–Ni film as a conducting diffusion barrier layer for integrating ferroelectric capacitor on Si

    Energy Technology Data Exchange (ETDEWEB)

    Dai, X.H. [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China); College of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401 (China); Guo, J.X.; Zhang, L.; Jia, D.M.; Qi, C.G.; Zhou, Y.; Li, X.H.; Shi, J.B.; Fu, Y.J.; Wang, Y.L.; Lou, J.Z. [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China); Ma, L.X. [Department of Physics, Blinn College, Bryan, TX 77805 (United States); Zhao, H.D. [College of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401 (China); Liu, B.T., E-mail: btliu@hbu.cn [Hebei Key Lab of Optic-electronic Information and Materials, College of Physics Science & Technology, Hebei University, Hebei 071002 (China)

    2015-10-05

    Highlights: • 4-nm-thick amorphous Nb–Ni film is first used as the conducting barrier layer. • No obvious interdiffusion/reaction can be found from the LSCO/PZT/LSCO/Nb–Ni/Si. • The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties. • Ultrathin amorphous Nb–Ni film is ideal to fabricate silicon-based FRAM. - Abstract: We have successfully integrated La{sub 0.5}Sr{sub 0.5}CoO{sub 3}/PbZr{sub 0.4}Ti{sub 0.6}O{sub 3}/La{sub 0.5}Sr{sub 0.5}CoO{sub 3} (LSCO/PZT/LSCO) capacitors on silicon substrate using a ∼4.0-nm-thick amorphous Nb–Ni film as the conducting diffusion barrier layer. Transmission electron microscopy technique confirms that the Nb–Ni film is still amorphous after fabrication of the capacitors, and the interfaces related to Nb–Ni are clean and sharp without any findable interdiffusion/reaction. The LSCO/PZT/LSCO capacitor, measured at 5 V, possesses very good properties, such as large remanent polarization of ∼22.1 μC/cm{sup 2}, small coercive voltage of ∼1.27 V, good fatigue-resistance, and small pulse width dependence, implying that ultrathin amorphous Nb–Ni film is ideal as the conducting diffusion barrier layer to fabricate high-density silicon-based ferroelectric random access memories.

  11. Fabrication, Testing and Integration Technologies of Polymer Microlens for Pt/Si Schottky-Barrier Infrared Charge Coupled Device Applications

    Institute of Scientific and Technical Information of China (English)

    KE Cai-Jun; YI Xin-Jian; LAI Jian-Jun; CHEN Si-Hai

    2005-01-01

    @@ A novel polymer refractive microlens array has been formed on the surface of 256(V)×290(H) PtSi Schottkybarrier infrared charge coupled device (IRCCD) image sensors to improve the photoresponsivity of the IRCCD.The fabrication process flows of polymer microlens array are described. An effective aperture ratio in excess of 92% of microlens array has been achieved. An experimental facility to evaluate the optical performance ofmicrolens array is introduced. The measurement results show that the microlens array indicates better than 4% non-uniformity of focal length and high optical performance. The application of the microlens array to improve the photosensitivity of infrared CCD is discussed.

  12. UVSiPM: A light detector instrument based on a SiPM sensor working in single photon counting

    Energy Technology Data Exchange (ETDEWEB)

    Sottile, G.; Russo, F.; Agnetta, G. [Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, IASF-Pa/INAF, Palermo (Italy); Belluso, M.; Billotta, S. [Osservatorio Astrofisico di Catania, OACT/INAF, Catania (Italy); Biondo, B. [Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, IASF-Pa/INAF, Palermo (Italy); Bonanno, G. [Osservatorio Astrofisico di Catania, OACT/INAF, Catania (Italy); Catalano, O.; Giarrusso, S. [Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, IASF-Pa/INAF, Palermo (Italy); Grillo, A. [Osservatorio Astrofisico di Catania, OACT/INAF, Catania (Italy); Impiombato, D.; La Rosa, G.; Maccarone, M.C.; Mangano, A. [Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, IASF-Pa/INAF, Palermo (Italy); Marano, D. [Osservatorio Astrofisico di Catania, OACT/INAF, Catania (Italy); Mineo, T.; Segreto, A.; Strazzeri, E. [Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, IASF-Pa/INAF, Palermo (Italy); Timpanaro, M.C. [Osservatorio Astrofisico di Catania, OACT/INAF, Catania (Italy)

    2013-06-15

    UVSiPM is a light detector designed to measure the intensity of electromagnetic radiation in the 320–900 nm wavelength range. It has been developed in the framework of the ASTRI project whose main goal is the design and construction of an end-to-end Small Size class Telescope prototype for the Cherenkov Telescope Array. The UVSiPM instrument is composed by a multipixel Silicon Photo-Multiplier detector unit coupled to an electronic chain working in single photon counting mode with 10 nanosecond double pulse resolution, and by a disk emulator interface card for computer connection. The detector unit of UVSiPM is of the same kind as the ones forming the camera at the focal plane of the ASTRI prototype. Eventually, the UVSiPM instrument can be equipped with a collimator to regulate its angular aperture. UVSiPM, with its peculiar characteristics, will permit to perform several measurements both in lab and on field, allowing the absolute calibration of the ASTRI prototype.

  13. UVSiPM: a light detector instrument based on a SiPM sensor working in single photon counting

    CERN Document Server

    Sottile, G; Agnetta, G; Belluso, M; Billotta, S; Biondo, B; Bonanno, G; Catalano, O; Giarrusso, S; Grillo, A; Impiombato, D; La Rosa, G; Maccarone, M C; Mangano, A; Marano, D; Mineo, T; Segreto, A; Strazzeri, E; Timpanaro, M C; 10.1016/j.nuclphysbps.2013.05.040

    2013-01-01

    UVSiPM is a light detector designed to measure the intensity of electromagnetic radiation in the 320-900 nm wavelength range. It has been developed in the framework of the ASTRI project whose main goal is the design and construction of an end-to-end Small Size class Telescope prototype for the Cherenkov Telescope Array. The UVSiPM instrument is composed by a multipixel Silicon Photo-Multiplier detector unit coupled to an electronic chain working in single photon counting mode with 10 nanosecond double pulse resolution, and by a disk emulator interface card for computer connection. The detector unit of UVSiPM is of the same kind as the ones forming the camera at the focal plane of the ASTRI prototype. Eventually, the UVSiPM instrument can be equipped with a collimator to regulate its angular aperture. UVSiPM, with its peculiar characteristics, will permit to perform several measurements both in lab and on field, allowing the absolute calibration of the ASTRI prototype.

  14. UVSiPM: A light detector instrument based on a SiPM sensor working in single photon counting

    Science.gov (United States)

    Sottile, G.; Russo, F.; Agnetta, G.; Belluso, M.; Billotta, S.; Biondo, B.; Bonanno, G.; Catalano, O.; Giarrusso, S.; Grillo, A.; Impiombato, D.; La Rosa, G.; Maccarone, M. C.; Mangano, A.; Marano, D.; Mineo, T.; Segreto, A.; Strazzeri, E.; Timpanaro, M. C.

    2013-06-01

    UVSiPM is a light detector designed to measure the intensity of electromagnetic radiation in the 320-900 nm wavelength range. It has been developed in the framework of the ASTRI project whose main goal is the design and construction of an end-to-end Small Size class Telescope prototype for the Cherenkov Telescope Array. The UVSiPM instrument is composed by a multipixel Silicon Photo-Multiplier detector unit coupled to an electronic chain working in single photon counting mode with 10 nanosecond double pulse resolution, and by a disk emulator interface card for computer connection. The detector unit of UVSiPM is of the same kind as the ones forming the camera at the focal plane of the ASTRI prototype. Eventually, the UVSiPM instrument can be equipped with a collimator to regulate its angular aperture. UVSiPM, with its peculiar characteristics, will permit to perform several measurements both in lab and on field, allowing the absolute calibration of the ASTRI prototype.

  15. Optical property of CR-39 synthesized by doping with methylviologen-encapsulated SiO2 nanocapsules as a solid-state X-ray plate detector

    Science.gov (United States)

    Miyoshi, Hirokazu; Kida, Fumio; Yamada, Kenji; Tsuchiya, Koichiro; Hase, Hitoshi

    2016-05-01

    A CR-39 plate synthesized by doping with methylviologen-encapsulated SiO2 nanocapsules was firstly demonstrated as a solid-state X-ray (80 kV) detector for diagnostic examination without etching using an alkali solution. The X-ray-irradiated area was clearly observed as an emission image by exciting with a laser in FLA-9000. The maximum intensity was obtained using a 532 nm laser. The emission intensity at the X-ray-irradiated area increased linearly from 0.5 to 3 Gy with increasing thickness from 1 to 5 mm. In 15-nm-diameter silica nanocapsules and 4-5-mm-thick CR-39, the maximum intensity was observed by X-ray irradiation.

  16. Influence of dopants on the glow curve structure and energy dependence of LiF:Mg, Cu, Si detectors

    OpenAIRE

    Knežević, Željka; Ranogajec-Komor, Maria; Miljanić, Saveta; Lee, Jungil; Kim, Jang-Lyul; Musić, Svetozar

    2011-01-01

    LiF thermoluminescent material doped with Mg, Cu and Si recently developed by the Korea Atomic Energy Research Institute (KAERI) has shown very good dosimetric properties. Since the thermoluminescence in LiF was found to be dependent on the proper combination of dopants, the investigation of the concentration and type of dopants is very important in developing and characterisation of new TL materials. The aim of this work was to determine the influence of type and concentration of activators ...

  17. Dimensionless parameterization of lidar for laser remote sensing of the atmosphere and its application to systems with SiPM and PMT detectors.

    Science.gov (United States)

    Agishev, Ravil; Comerón, Adolfo; Rodriguez, Alejandro; Sicard, Michaël

    2014-05-20

    In this paper, we show a renewed approach to the generalized methodology for atmospheric lidar assessment, which uses the dimensionless parameterization as a core component. It is based on a series of our previous works where the problem of universal parameterization over many lidar technologies were described and analyzed from different points of view. The modernized dimensionless parameterization concept applied to relatively new silicon photomultiplier detectors (SiPMs) and traditional photomultiplier (PMT) detectors for remote-sensing instruments allowed predicting the lidar receiver performance with sky background available. The renewed approach can be widely used to evaluate a broad range of lidar system capabilities for a variety of lidar remote-sensing applications as well as to serve as a basis for selection of appropriate lidar system parameters for a specific application. Such a modernized methodology provides a generalized, uniform, and objective approach for evaluation of a broad range of lidar types and systems (aerosol, Raman, DIAL) operating on different targets (backscatter or topographic) and under intense sky background conditions. It can be used within the lidar community to compare different lidar instruments. PMID:24922200

  18. A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm{sup 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yamaya, Taiga; Mitsuhashi, Takayuki; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Matsumoto, Takahiro; Kawai, Hideyuki; Suga, Mikio [Chiba University, 1-33 Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Watanabe, Mitsuo, E-mail: taiga@nirs.go.jp [Central Research Laboratory, Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu 434-8601 (Japan)

    2011-11-07

    We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm{sup 3} cubic crystals, in contrast to our previous development using 3.0 mm{sup 3} cubic crystals. The crystal block was composed of a 16 x 16 x 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 x 0.993 x 0.993 mm{sup 3} in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 x 4 array of MPPCs), each having a sensitive area of 3.0 x 3.0 mm{sup 2}, were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons.

  19. Cerenkov light identification with Si low-temperature detectors with Neganov-Luke effect-enhanced sensitivity

    CERN Document Server

    Gironi, L; Brofferio, C; Capelli, S; Carniti, P; Cassina, L; Clemenza, M; Cremonesi, O; Faverzani, M; Ferri, E; Fossati, E; Giachero, A; Gotti, C; Maino, M; Margesin, B; Moretti, F; Nucciotti, A; Pavan, M; Pessina, G; Pozzi, S; Previtali, E; Puiu, A; Sisti, M; Terranova, F

    2016-01-01

    A new generation of cryogenic light detectors exploiting Neganov-Luke effect to enhance the thermal signal has been used to detect the Cherenkov light emitted by the electrons interacting in TeO$_{2}$ crystals. With this mechanism a high significance event-by-event discrimination between alpha and beta/gamma interactions at the $^{130}$Te neutrino-less double beta decay Q-value - (2527.515 $\\pm$ 0.013) keV - has been demonstrated. This measurement opens the possibility of drastically reducing the background in cryogenic experiments based on TeO$_{2}$.

  20. Novel Photo-Detectors and Photo-Detector Systems

    OpenAIRE

    Danilov, M.

    2008-01-01

    Recent developments in photo-detectors and photo-detector systems are reviewed. The main emphasis is made on Silicon Photo-Multipliers (SiPM) - novel and very attractive photo-detectors. Their main features are described. Properties of detectors manufactured by different producers are compared. Different applications are discussed including calorimeters, muon detection, tracking, Cherenkov light detection, and time of flight measurements.

  1. Investigation of enzyme-sensitive lipid nanoparticles for delivery of siRNA to blood–brain barrier and glioma cells

    Directory of Open Access Journals (Sweden)

    Bruun J

    2015-09-01

    Full Text Available Jonas Bruun,1 Trine B Larsen,1 Rasmus I Jølck,1 Rasmus Eliasen,1 René Holm,2 Torben Gjetting,1 Thomas L Andresen11Department of Micro- and Nanotechnology, Center for Nanomedicine and Theranostics, Technical University of Denmark, DTU Nanotech, Lyngby, Denmark; 2H Lundbeck A/S, Biologics and Pharmaceutical Science, Valby, DenmarkAbstract: Clinical applications of siRNA for treating disorders in the central nervous system require development of systemic stable, safe, and effective delivery vehicles that are able to cross the impermeable blood–brain barrier (BBB. Engineering nanocarriers with low cellular interaction during systemic circulation, but with high uptake in targeted cells, is a great challenge and is further complicated by the BBB. As a first step in obtaining such a delivery system, this study aims at designing a lipid nanoparticle (LNP able to efficiently encapsulate siRNA by a combination of titratable cationic lipids. The targeted delivery is obtained through the design of a two-stage system where the first step is conjugation of angiopep to the surface of the LNP for targeting the low-density lipoprotein receptor-related protein-1 expressed on the BBB. Second, the positively charged LNPs are masked with a negatively charged PEGylated (poly(ethylene glycol cleavable lipopeptide, which contains a recognition sequence for matrix metalloproteinases (MMPs, a class of enzymes often expressed in the tumor microenvironment and inflammatory BBB conditions. Proteolytic cleavage induces PEG release, including the release of four glutamic acid residues, providing a charge switch that triggers a shift of the LNP charge from weakly negative to positive, thus favoring cellular endocytosis and release of siRNA for high silencing efficiency. This work describes the development of this two-stage nanocarrier-system and evaluates the performance in brain endothelial and glioblastoma cells with respect to uptake and gene silencing efficiency. The

  2. A New Large-Well 1024x1024 Si:As Detector for the Mid-Infrare

    CERN Document Server

    Mainzer, A K; Stapelbroek, M; Hogue, H; Molyneux, D; Ressler, M; Atkins, E; Reekstin, J; Werner, M; Young, E T

    2005-01-01

    We present a description of a new 1024x1024 Si:As array designed for ground-based use from 5 - 28 microns. With a maximum well depth of 5e6 electrons, this device brings large-format array technology to bear on ground-based mid-infrared programs, allowing entry to the megapixel realm previously only accessible to the near-IR. The multiplexer design features switchable gain, a 256x256 windowing mode for extremely bright sources, and it is two-edge buttable. The device is currently in its final design phase at DRS in Cypress, CA. We anticipate completion of the foundry run in the beginning of 2006. This new array will enable wide field, high angular resolution ground-based follow up of targets found by space-based missions such as the Spitzer Space Telescope and the Widefield Infrared Survey Explorer (WISE).

  3. Barrier Infrared Detector (BIRD) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — JPL will design, fabricate, and fully characterize a 640x512 format HOT-BIRD FPA with increased quantum efficiency and extended spectral coverage. Unlike the small...

  4. Multilayer moisture barrier

    Energy Technology Data Exchange (ETDEWEB)

    Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

    2015-04-21

    A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

  5. Charge transport properties of p-CdTe/n-CdTe/n+-Si diode-type nuclear radiation detectors based on metalorganic vapor-phase epitaxy-grown epilayers

    International Nuclear Information System (INIS)

    Charge transport properties of p-CdTe/n-CdTe/n+-Si diode-type nuclear radiation detectors, fabricated by growing p-and n-type CdTe epilayers on (211) n+-Si substrates using metalorganic vapor-phase epitaxy (MOVPE), were studied by analyzing current-voltage characteristics measured at various temperatures. The diode fabricated shows good rectification properties, however, both forward and reverse biased currents deviate from their ideal behavior. The forward current exhibits typical feature of multi-step tunneling at lower biases; however, becomes space charge limited type when the bias is increased. On the other hand, the reverse current exhibits thermally activated tunneling-type current. It was found that trapping centers at the p-CdTe/n-CdTe junction, which were formed due to the growth induced defects, determine the currents of this diode, and hence limit the performance of the nuclear radiation detectors developed

  6. Design on Low-noise Charge Sensitive Preamplifier for High Resolution Si-PIN Detectors%用于高分辨率 Si -PIN 探测器的低噪声电荷灵敏前置放大器的设计

    Institute of Scientific and Technical Information of China (English)

    刘洋; 田华阳; 何高魁; 黄小健; 郝晓勇; 继世梁

    2014-01-01

    This paper describes the design of low -noise transistor reset mechanism charge sensitive preamplifier for high resolution Si -PIN detectors.With 6μs shaping time,The preamplifier`s zero-capacitance electronics noise is 150 eV( to Si detector ) when the JFET of preamplifier cooled to -20℃.Coupled with a 5 mm2 sensi-tive area, 500 μm thickness Si -PIN detector manufactured by planar technology , the best energy resolution of 5.9 keV X ray can reach to 195eV ,while the detector and JFET cooled with two stage peltier to -20℃.%介绍了一种用于高分辨率Si-PIN探测器的低噪声晶体管反馈电荷灵敏前置放大器的设计。在场效应管制冷到-20℃,成形时间为6μs条件下,前放的零电容电子学噪声(对Si探测器)为150 eV。与平面工艺技术制备的厚度500μm,灵敏面积5 mm2的Si -PIN探测器配用,采用小型温差电制器制冷至-20℃,对5.9 keV X射线的能量分辨率( FWHM)最好可以达到195 eV。

  7. SiD Letter of Intent

    CERN Document Server

    Aihara, H; Oreglia, M.; Berger, E.L.; Guarino, V.; Repond, J.; Weerts, H.; Xia, L.; Zhang, J.; Zhang, Q.; Srivastava, A.; Butler, J.M.; Goldstein, Joel; Velthuis, J.; Radeka, V.; Zhu, R.-Y.; Lutz, P.; de Roeck, A.; Elsener, K.; Gaddi, A.; Gerwig, H.; Grefe, C.; Klempt, W.; Linssen, L.; Schlatter, D.; Speckmayer, P.; Thom, J.; Yang, J.; Christian, D.C.; Cihangir, S.; Cooper, W.E.; Demarteau, M.; Fisk, H.E.; Garren, L.A.; Krempetz, K.; Kutschke, R.K.; Lipton, R.; Para, A.; Tschirhart, R.; Wenzel, H.; Yarema, R.; Grunewald, M.; Pankov, A.; U., Gomel State Tech.; Dutta, T.; Dauncey, P.D.; Balbuena, J.P.; Fleta, C.; Lozano, M.; Ullan, M.; Christian, G.B.; Faus-Golfe, A.; Fuster, J.; Lacasta, C.; Marinnas, C.; Vos, M.; Duarte, J.; Fernandez, M.; Gonzalez, J.; Jaramillo, R.; Lopez, Virto, A.; Martinez-Eivero, C.; Moya, D.; Ruiz-Mimeno, A.; Vila, I.; Colledani, C.; Dorokhov, A.; Hu-Guo, C.; Winter, M.; Moortgat-Pick, G.; Onoprienko, D.V.; Kim, G.N.; Park, H.; Adloff, C.; Blaha, J.; Blaising, J.-J.; Cap, S.; Chefdeville, M.; Drancourt, C.; Espargiliare, A.; Gaglione, R.; Geffroy, N.; Jacquemier, J.; Karyotakis, Y.; Prast, J.; Vouters, G.; Gronberg, J.; Walston, S.; Wright, D.; Sawyer, L.; Laloum, M.; Ciobanu, C.; Chauveau, J.; Savoy-Navarro, A.; Andricek, L.; Moser, H.-G.; Cowan, R.f.; Fisher, P.; Yamamoto, R.K.; Kenney, ClMl; Boos, E.E.; Merkin, M.; Chen, S.; Chakraborty, D.; Dyshkant, A.; Hedin, D.; Zutshi, V.; Galkin, V.; D'Ascenzo, N.; Ossetski, D.; Saveliev, V.; Kapusta, F.; De Masi, R.; Vrba, V.; Lu, C.; McDonald, K.T.; Smith, A.J.S.; Bortoletto, D.; Coath, R.; Crooks, J.; Damerell, C.; Gibson, M.; Nichols, A.; Stanitzki, M.; Strube, J.; Turchetta, R.; Tyndel, M.; Weber, M.; Worm, S.; Zhang, Z.; Barklow, T.L.; Belymam, A.; Breidenbach, M.; Cassell, R.; Craddock, W.; Deaconu, C.; Dragone, A.; Graf, N.A.; Haller, G.; Herbst, R.; Hewett, J.L.; Jaros, J.A.; Johnson, A.S.; Kim, P.C.; MacFarlane, D.B.; Markiewicz, T.; Maruyama, T.; McCormick, J.; Moffeit, K.; Neal, H.A.; Nelson, T.K.; Oriunno, M.; Partridge, R.; Peskin, M.E.; Rizzo, T.G.; Rowson, P.; Su, D.; Woods, M.; Chakrabarti, S.; Dieguez, A.; Garrido, Ll.; Kaminski, J.; Conway, J.S.; Chertok, M.; Gunion, J.; Holbrook, B.; Lander, R.L.; Tripathi, S.M.; Fadeyev, V.; Schumm, B.A.; Oreglia, M.; Gill, J.; Nauenberg, U.; Oleinik, G.; Wagner, S.R.; Ranjan, K.; Shivpuri, R.; Varner, G.S.; Orava, R.; Van Kooten, R.; Bilki, B.; Charles, M.; Kim, T.J.; Mallik, U.; Norbeck, E.; Onel, Y.; Brau, B.P.; Willocq, S.; Taylor, G.N.; Riles, Keith; Yang, H.-J.; Kriske, R.; Cremaldi, L.; Rahmat, R.; Lastovicka-Medin, G.; Seidel, S.; Hildreth, M.D.; Wayne, M.; Brau, J.E.; Frey, R.; Sinev, N.; Strom, D.M.; Torrence, E.; Banda, Y.; Burrows, P.N.; Devetak, E.; Foster, B.; Lastovicka, T.; Li, Y.-M.; Nomerotski, A.; Riera-Babures, J.; Vilasis-Cardona, X.; Manly, S.; Adeva, B.; Iglesias Escudero, C.; Vazquez Regueiro, P.; Saborido Silva, J.J.; Gallas Torreira, A.; Gao, D.; Jie, W.; Jungfeng, Y.; Li, C.; Liu, S.; Liu, Y.; Sun, Y.; Wang, Q.; Yi, J.; Yonggang, W.; Zhao, Z.; De, K.; Farbin, A.; Park, S.; Smith, J.; White, A.P.; Yu, J.; Lou, X.C.; Abe, T.; Aihara, H.; Iwasaki, M.; Lubatti, H.J.; Band, H.R.; Feyzi, F.; Prepost, R.; Karchin, P.E.; Milstene, C.; Baltay, C.; Dhawan, S.; Kwon, Y.-J.

    2009-01-01

    Letter of intent describing SiD (Silicon Detector) for consideration by the International Linear Collider IDAG panel. This detector concept is founded on the use of silicon detectors for vertexing, tracking, and electromagnetic calorimetry. The detector has been cost-optimized as a general-purpose detector for a 500 GeV electron-positron linear collider.

  8. Improved neutron radiation hardness for Si detectors: Application of low resistivity starting material and/or manipulation of N{sub eff} by selective filling of radiation-induced traps at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dezillie, B.; Li, Z. [Brookhaven National Lab., Upton, NY (United States); Eremin, V. [Academy of Science of Russia (Russian Federation). A.F. Ioffe Physico-Technical Inst.; Bruzzi, M.; Pirollo, S. [Dipt. di Energetica, Firenze (Italy); Pandey, S.U. [Wayne State Univ., Detroit, MI (United States); Li, C.J. [Chinese Academy of Science, Beijing (China). Inst. of Semiconductors

    1999-06-01

    Radiation-induced electrical changes in both space charge region (SCR) of Si detectors and bulk material (BM) have been studied for samples of diodes and resistors made on Si materials with different initial resistivities. The space charge sign inversion fluence ({Phi}{sub inv}) has been found to increase linearly with the initial doping concentration (the reciprocal of the resistivity), which gives improved radiation hardness to Si detectors fabricated from low resistivity material. The resistivity of the BM, on the other hand, has been observed to increase with the neutron fluence and approach a saturation value in the order of hundreds k{Omega}cm at high fluences, independent of the initial resistivity and material type. However, the fluence ({Phi}{sub s}), at which the resistivity saturation starts, increases with the initial doping concentrations and the value of {Phi}{sub s} is in the same order of that of {Phi}{sub inv} for all resistivity samples. Improved radiation hardness can also be achieved by the manipulation of the space charge concentration (N{sub eff}) in SCR, by selective filling and/or freezing at cryogenic temperatures the charge state of radiation-induced traps, to values that will give a much smaller full depletion voltage. Models have been proposed to explain the experimental data.

  9. Behaviour of semiconductor nuclear-particle detectors

    International Nuclear Information System (INIS)

    Experimental and theoretical studies of the behaviour of semiconductor nuclear-particle detectors have been carried out over the temperature range of 0.2oK to 300oK. A simple theoretical model for the detector behaviour, which is found to describe the observed behaviour over a wide range of parameters, is presented. The importance of semiconductor purity and bias voltage in connection with pulse height, pulse rise-time and detector area is discussed. Empirical studies of noise and energy resolution indicate that for alpha particles the smallest observed peak-widths are substantially larger than those expected on the basis of electrical noise from the detector and amplifier. Equivalent noise values of ≤ 3 keV full-width at half maximum (FWHM) have been found for a 40-mm2 silicon surface-barrier detector at 77oK. Semiconductor detectors exhibit a ''pulse-height defect'' for fission fragments. There is evidence that this defect is not caused by a ''dead layer''. If electric fields which are insufficient to insure complete ''collection'' are responsible for the defect, the necessary minimum field (at the surface) is > 3 x 104 V/cm for fission fragments, as compared to the value of 2 x 103 V/cm which is found necessary in the case of alpha particles in Ge and Si. Detailed considerations regarding pulse rise-time at the amplifier have shown that in high-resistivity material both the ''dielectric'' relaxation time and the resistance associated with the undepleted base material can play an important role. A quantative description of the effect of detector and amplifier parameters on the shapes and rise-times associated with the pulse are presented. The advantages and problems associated with the use of surface-barrier detectors in several unique low-temperature nuclear-alignment experiments are discussed. These experiments involved fission-fragment angular distributions and resolution of alpha-fine structure with long-term stability. Matched expansion

  10. Photoelectric properties of n-SiC/n-Si heterojunctions

    Directory of Open Access Journals (Sweden)

    Semenov A. V.

    2012-10-01

    Full Text Available Photovoltaic effect in isotype heterotructure formed by nanocrystalline silicon carbide films on single crystal n-Si substrates (n-SiC/n-Si heterojunction was studied. The films were produced by direct ionic deposition method. The model that takes into account the quantum wells and potential barriers caused by band offsets was proposed to explain the current-voltage characteristics and photovoltaic properties of the heterostructure n-SiC/n-Si.

  11. Time-of-flight ERD with a 200 mm{sup 2} Si{sub 3}N{sub 4} window gas ionization chamber energy detector

    Energy Technology Data Exchange (ETDEWEB)

    Julin, Jaakko, E-mail: jaakko.julin@jyu.fi; Laitinen, Mikko; Sajavaara, Timo

    2014-08-01

    Low energy heavy ion elastic recoil detection work has been carried out in Jyväskylä since 2009 using home made timing detectors, a silicon energy detector and a timestamping data acquisition setup forming a time-of-flight–energy telescope. In order to improve the mass resolution of the setup a new energy detector was designed to replace the silicon solid state detector, which suffered from radiation damage and had poor resolution for heavy recoils. In this paper the construction and operation of an isobutane filled gas ionization chamber with a 14 × 14 mm{sup 2} 100 nm thick silicon nitride window are described. In addition to greatly improved energy resolution for heavy ions, the detector is also able to detect hydrogen recoils simultaneously in the energy range of 100–1000 keV. Additionally the detector has position sensitivity by means of timing measurement, which can be performed without compromising the performance of the detector in any other way. The achieved position sensitivity improves the depth resolution near the surface.

  12. The international linear collider. Technical design report. Vol. 4. Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Ties; Brau, James E.; Burrows, Philip; Fuster, Juan; Peskin, Michael; Stanitzki, Marcel; Sugimoto, Yasuhiro; Yamada, Sakue; Yamamoto, Hitoshi (eds.)

    2013-10-01

    The following topics are dealt with: The Si Vertex detectors, the main tracker, calorimetry, muon detectors, the superconducting spectrometer magnet, the detector electronics and data acquisition, simulation and reconstruction, benchmarking, costs. (HSI)

  13. The international linear collider. Technical design report. Vol. 4. Detectors

    International Nuclear Information System (INIS)

    The following topics are dealt with: The Si Vertex detectors, the main tracker, calorimetry, muon detectors, the superconducting spectrometer magnet, the detector electronics and data acquisition, simulation and reconstruction, benchmarking, costs. (HSI)

  14. C2H2流量对SiCN 薄膜结构及阻挡性能的影响%Influence of C2H2 Flow Rate on Microstructures and Electronic Properties of SiCN Diffusion Barriers

    Institute of Scientific and Technical Information of China (English)

    张治超; 周继承; 彭银桥

    2011-01-01

    The SiCN films were grown by RF reactive magnetrmn sputtering with acetylene and nitrogen as the reactive gases,and polycrystalline silicon as the target material. The impacts of the film growth conditions,including the C2H2 flow rate, annealing temperature on the properties of the SiCN film were studied. Its microstructures and electronic properties were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, and conventional surface probes.The results show that the C2H2 flow rate and annealing temperature strongly affect its microstructures, dielectric constant and diffusion barrier efficiency. For instance,as C2H2 flow rate increases,the grain size on surfaces of the highly stable,amorphous SiCN film increases. The C-N bonds dominate the surface matrix possibly because of substitution of Si for C atom. Its dielectric constant was estimated to be 4.2 ~ 5.8, depending on contents C and N, and on defect-density of the films. We found that high temperature inter-diffusion and reaction of Cu and Si are responsible for the breakdown of the SiCN diffusion barrier%采用C2H2和N2作为反应气体、多晶Si作为靶材,利用射频磁控溅射系统沉积了SiCN薄膜.利用傅里叶红外光谱仪、X射线衍射仪、四探针测试仪等研究了C2H2流量对薄膜结构、介电常数以及阻挡性能的影响.结果表明,薄膜为非晶结构,1000℃退火下未出现结晶,稳定性很好;随着C2H2流量的增大,薄膜表面颗粒呈现增大趋势;C原子取代Si原子占据薄膜中的网络位置,薄膜形成了以C-N键为主的网络结构;制得的SiCN薄膜介电常数在4.2~5.8之间,C,N含量以及薄膜结构是影响介电性能的关键因素,高温使得Cu穿过薄膜中的缺陷与Si发生互扩散是薄膜阻挡性能失效的主要原因.

  15. Heavy ion recoil spectrometry of Si{sub x}Ge{sub 1-x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Walker, S.R.; Johnston, P.N.; Bubb, I.F. [Royal Melbourne Inst. of Tech., VIC (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Hult, M.; Whitlow, H.J. [Lund Institute of Technology, Solvegatan (Sweden). Department of Nuclear Physics; Zaring, C.; Oestling, M. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Solid State Electronics

    1993-12-31

    Mass and energy dispersive recoil spectrometry employing 77 MeV {sup 127}I ions from ANTARES (FN Tandem) facility at Lucas Heights has been used to examine the isotopic composition of samples of Si{sub x}Ge{sub 1-x} grown at the Australian National University by Electron Beam Evaporation (EBE). The recoiling target nuclei were analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained. Recoil spectrometry has shown the presence of oxygen in the Si{sub x}Ge{sub 1-x} layer and has enabled the separate determination of energy spectra for individual elements. 9 refs., 3 figs.

  16. Silicon Detector Letter of Intent

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, H.; Burrows, P.; Oreglia, M.

    2010-05-26

    This document presents the current status of SiD's effort to develop an optimized design for an experiment at the International Linear Collider. It presents detailed discussions of each of SiD's various subsystems, an overview of the full GEANT4 description of SiD, the status of newly developed tracking and calorimeter reconstruction algorithms, studies of subsystem performance based on these tools, results of physics benchmarking analyses, an estimate of the cost of the detector, and an assessment of the detector R&D needed to provide the technical basis for an optimised SiD.

  17. Characterization of imaging pixel detectors of Si and CdTe read out with the counting X-ray chip MPEC 2.3; Charakterisierung von bildgebenden Pixeldetektoren aus Si und CdTe ausgelesen mit dem zaehlenden Roentgenchip MPEC 2.3

    Energy Technology Data Exchange (ETDEWEB)

    Loecker, M.

    2007-04-15

    Single photon counting detectors with Si- and CdTe-sensors have been constructed and characterized. As readout chip the MPEC 2.3 is used which consists of 32 x 32 pixels with 200 x 200 {mu}m{sup 2} pixel size and which has a high count rate cabability (1 MHz per pixel) as well as a low noise performance (55 e{sup -}). Measurements and simulations of the detector homogeneity are presented. It could be shown that the theoretical maximum of the homogeneity is reached (quantum limit). By means of the double threshold of the MPEC chip the image contrast can be enhanced which is demonstrated by measurement and simulation. Also, multi-chip-modules consisting of 4 MPEC chips and a single Si- or CdTe-sensor have been constructed and successfully operated. With these modules modulation-transfer-function measurements have been done showing a good spatial resolution of the detectors. In addition, multi-chip-modules according to the Sparse-CMOS concept have been built and tests characterizing the interconnection technologies have been performed.

  18. The influence of high-energy electrons irradiation on the electrical properties of Schottky barrier detectors based on semi-insulating GaAs

    Science.gov (United States)

    Zatko, B.; Sagatova, A.; Bohacek, P.; Sedlackova, K.; Sekacová, M.; Arbet, J.; Necas, V.

    2016-01-01

    In this work we fabricated detectors based on semi-insulating GaAs and studied their electrical properties (current-voltage characteristics, galvanomagnetic measurements) after irradiation with 5 MeV electrons from a linear accelerator up to a dose of 104 kGy. A series of detectors were prepared using Ti/Pt/Au Schottky contact with 1 mm diameter. The thickness of the base material was about 230 μm. A whole area Ni/AuGe/Au ohmic contact was evaporated on the back side. For galvanomagnetic measurements we used three samples from the same wafer. All samples were irradiated by a pulse beam of 5 MeV electrons using the linear accelerator in 11 steps, where the accumulative dose increased from 1 kGy up to 104 kGy. Also different dose rates (20, 40 and 80 kGy/h) were applied to the samples. After each irradiation step we performed electrical measurement of each sample. We analyze the electron Hall mobility, resistivity, electron Hall concentration, breakdown voltage and reverse current of samples before and after irradiation using different dose rates.

  19. 聚乳酸薄膜表面SiOx层的制备与阻隔性研究%Preparation and Barrier Property of SiOx Layer on Polylactic Acid Film

    Institute of Scientific and Technical Information of China (English)

    张新林; 许文才; 王正铎; 霍俐霞

    2010-01-01

    聚乳酸是一种可完全生物降解的新型绿色包装材料,由于其良好的物理机械性能、生物相容性,可吸收性及对人体和环境的无毒性等,广泛应用干各种包装领域.本研究利用等离子体增强化学气相沉积法在厚度为40μm的聚乳酸(PLA)基材上制备阻隔性能优良的SiOx层.制备的SiOx层无色透明且与基材附着牢固.实验分别采用FTIR、SEM和AFM对沉积的SiOx层进行结构和表面性能分析,以表面轮廓仪测量SiOx层厚度,以透氧仪和透湿仪表征SiOx层的阻隔性.结果表明:制备的SiOx层表面结构均匀致密,平均厚度为174nm,透氧率从原膜的167.52cm3/(m2·24h)降低到17.88cm3/(m2·24h),透湿率从原膜的132.93g/(m2·24h)降低到15.23g/(m2·24h),阻隔性能明显改善.

  20. A PET detector module with monolithic crystal, single end readout, SiPM array and high depth-of-interaction resolution

    Science.gov (United States)

    Zhang, H.; Zhou, R.; Yang, C.

    2016-08-01

    Depth of interaction (DOI) technology can improve the spatial resolution of nuclear medicine imaging system which uses scintillation detectors such as Positron Emission Tomography (PET). In this paper, a prototype detector module with DOI capability is established to make complementary characteristic tests on an existing method and to improve the experimental performance using the same method. We investigate the gamma incident surface and incident angle effects on the positioning method with our model in simulations and evaluate its 3-D positioning results in experiment. It shows that the positioning results are highly affected by the gamma incident surface and incident angle. The 137Cs energy resolution is 12.1% and the DOI resolution is estimated at 2.26 mm in average by our detector in experiment.

  1. Sub-millimetre DOI detector based on monolithic LYSO and digital SiPM for a dedicated small-animal PET system.

    Science.gov (United States)

    Marcinkowski, Radosław; Mollet, Pieter; Van Holen, Roel; Vandenberghe, Stefaan

    2016-03-01

    The mouse model is widely used in a vast range of biomedical and preclinical studies. Thanks to the ability to detect and quantify biological processes at the molecular level in vivo, PET has become a well-established tool in these investigations. However, the need to visualize and quantify radiopharmaceuticals in anatomic structures of millimetre or less requires good spatial resolution and sensitivity from small-animal PET imaging systems.In previous work we have presented a proof-of-concept of a dedicated high-resolution small-animal PET scanner based on thin monolithic scintillator crystals and Digital Photon Counter photosensor. The combination of thin monolithic crystals and MLE positioning algorithm resulted in an excellent spatial resolution of 0.7 mm uniform in the entire field of view (FOV). However, the limitation of the scanner was its low sensitivity due to small thickness of the lutetium-yttrium oxyorthosilicate (LYSO) crystals (2 mm).Here we present an improved detector design for a small-animal PET system that simultaneously achieves higher sensitivity and sustains a sub-millimetre spatial resolution. The proposed detector consists of a 5 mm thick monolithic LYSO crystal optically coupled to a Digital Photon Counter. Mean nearest neighbour (MNN) positioning combined with depth of interaction (DOI) decoding was employed to achieve sub-millimetre spatial resolution. To evaluate detector performance the intrinsic spatial resolution, energy resolution and coincidence resolving time (CRT) were measured. The average intrinsic spatial resolution of the detector was 0.60 mm full-width-at-half-maximum (FWHM). A DOI resolution of 1.66 mm was achieved. The energy resolution was 23% FWHM at 511 keV and CRT of 529 ps were measured. The improved detector design overcomes the sensitivity limitation of the previous design by increasing the nominal sensitivity of the detector block and retains an excellent intrinsic spatial resolution. PMID:26907952

  2. PIN Diode Detectors

    Science.gov (United States)

    Ramírez-Jiménez, F. J.

    2008-07-01

    A review of the application of PIN diodes as radiation detectors in particle counting, X- and γ-ray spectroscopy, medical applications and charged particle spectroscopy is presented. As a practical example of its usefulness, a PIN diode and a low noise preamplifier are included in a nuclear spectroscopy chain for X-ray measurements. This is a laboratory session designed to review the main concepts needed to set up the detector-preamplifier array and to make measurements of X-ray energy spectra with a room temperature PIN diode. The results obtained are compared with those obtained with a high resolution cooled Si-Li detector.

  3. Performances of the Si microstrip detector of the STAR experiment at RHIC; Performances du detecteur en silicium a micropistes de l'experience STAR a RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet, J

    2007-10-15

    The Silicon Strip Detector (SSD) is the fourth layer of detector using a double-sided microstrip technology of the STAR experiment at RHIC, completing STAR's inner tracking device. The goal of STAR is to study heavy ions collisions in order to probe the existence of the quark gluon plasma (QGP), a deconfined state of nuclear matter. Strangeness enhancement, such as {kappa}{sub S}{sup 0}, {lambda}, {xi} and {omega}, for particles production, has been proposed to sign the formation of QGP. Then precise measurement of secondary vertices is needed. The SSD will also permit an attempt to use the inner tracking device to measure charm and beauty with direct topological identification. It was proposed to enhance the STAR tracking capabilities by providing a better connection between reconstructed tracks in the main tracking device (TPC) and the initial vertex detector (SVT). In this thesis, we will present the intrinsic performances of the SSD and its impact on the inner tracking system performances by studying Cu-Cu collisions occurred at RHIC in 2005. We show that the SSD detector has excellent performances in terms of resolution: (945 {+-} 18) {mu}m in azimuth and (1021 {+-} 13) {mu}m along the beam axis. For the final result when SSD is associated to the SVT the resolutions are (281 {+-} 1) {mu}m and (213 {+-} 0.8) {mu}m in azimuth and along the beam axis respectively. The resolution reached by the addition of the Silicon Vertex detectors of STAR will allow the search for rare particles like charm and beauty, which have a decay-length of the order of hundred microns.

  4. Role of the interfacial thermal barrier in the effective thermal diffusivity/conductivity of SiC-fiber-reinforced reaction-bonded silicon nitride

    Science.gov (United States)

    Bhatt, Hemanshu; Donaldson, Kimberly Y.; Hasselman, D. P. H.; Bhatt, R. T.

    1990-01-01

    Experimental thermal diffusivity data transverse to the fiber direction for composites composed of a reaction bonded silicon nitride matrix reinforced with uniaxially aligned carbon-coated silicon carbide fibers indicate the existence of a significant thermal barrier at the matrix-fiber interface. Calculations of the interfacial thermal conductances indicate that at 300 C and 1-atm N2, more than 90 percent of the heat conduction across the interface occurs by gaseous conduction. Good agreement is obtained between thermal conductance values for the oxidized composite at 1 atm calculated from the thermal conductivity of the N2 gas and those inferred from the data for the effective composite thermal conductivity.

  5. CAR siRNA 对睾丸支持细胞上皮屏障通透性的影响及机制%Effects of coxsackie-adenovirus′receptor siRNA on the permeability of Sertoli cell epithelial barrier and its related mechanism

    Institute of Scientific and Technical Information of China (English)

    李兴旺; 赵艳玲

    2014-01-01

    目的:观察柯萨奇病毒-腺病毒受体(CAR)siRNA对睾丸支持细胞上皮屏障通透性的影响,并探讨其机制。方法采用睾丸支持细胞原代双室培养方法制备睾丸支持细胞上皮屏障,细胞培养3 d后分为CAR siRNA组、对照组,分别转染CAR siRNA、无同源性非靶向双链RNA。转染后第2天,分别采用RT-PCR和Western blotting法检测睾丸支持细胞中CAR mRNA、蛋白表达;采用Millicell-ERS电阻系统测量双室模型内外室的电位差;采用免疫荧光细胞化学染色法检测支持细胞的Occludin蛋白,荧光显微镜下观察Occludin分布情况;采用Western blotting法检测支持细胞中总Occludin蛋白量、与早期内涵体抗原1(EEA1)抗体结合的Occludin蛋白。结果 CAR siRNA组与对照组CAR mRNA相对表达量分别为0.122±0.013、0.429±0.039,CAR 蛋白相对表达量分别为0.142±0.041、0.532±0.022,两组比较,P均<0.05。 CAR siRNA组与对照组TER分别为(37±2.5)、(50±3.0)ohm· cm2,两组比较,P<0.05。 CAR siRNA组与对照组Occludin蛋白相对表达量分别为0.164±0.025、0.143±0.031,两组比较,P>0.05。对照组Occludin呈蜂巢样沿细胞膜线状分布;CAR siRNA组Occludin分布较紊乱,细胞膜处减少,线性分布破坏,细胞质内增多。 CAR siRNA组、对照组细胞中与EEA1结合的Occludin蛋白量分别为1.332±0.018、1.000±0.015,两组比较,P<0.05。结论 CAR siRNA能增加睾丸支持细胞上皮屏障通透性,其机制可能与其诱导Occludin蛋白内吞增强而分布改变有关。%Objective To investigate the effect of coxsackie-adenovirus receptor(CAR) siRNA on the permeability of Sertoli cell epithelial barrier and its related mechanism.Methods By using two-compartment primary culture system, Sertoli cell epithelial barrier was established.After 3 days of culture, the cells were divided into control and

  6. Sub- and near-barrier fusion reactions experimental results

    Directory of Open Access Journals (Sweden)

    Montagnoli G.

    2016-01-01

    Furthermore, light heavy-ion systems show cross section oscillations above the Coulomb barrier. Recent experiments have been performed on the fusion of 28,30Si+28,30Si systems where all phenomena cited above show up. In particular regular oscillations that have been revealed above the barrier for 28Si+28Si and have been interpreted as the consequence of the strong channel couplings and/or the oblate deformation of 28Si.

  7. Cryogenic Tracking Detectors

    CERN Multimedia

    Luukka, P R; Tuominen, E M; Mikuz, M

    2002-01-01

    The recent advances in Si and diamond detector technology give hope of a simple solution to the radiation hardness problem for vertex trackers at the LHC. In particular, we have recently demonstrated that operating a heavily irradiated Si detector at liquid nitrogen (LN$_2$) temperature results in significant recovery of Charge Collection Efficiency (CCE). Among other potential benefits of operation at cryogenic temperatures are the use of large low-resistivity wafers, simple processing, higher and faster electrical signal because of higher mobility and drift velocity of carriers, and lower noise of the readout circuit. A substantial reduction in sensor cost could result The first goal of the approved extension of the RD39 program is to demonstrate that irradiation at low temperature in situ during operation does not affect the results obtained so far by cooling detectors which were irradiated at room temperature. In particular we shall concentrate on processes and materials that could significantly reduce th...

  8. Silicon detectors

    International Nuclear Information System (INIS)

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  9. Barriers to radiant barriers

    Energy Technology Data Exchange (ETDEWEB)

    Henke, C.

    Radiant barriers are an energy saving device which decrease the heat lost through radiant heat transfer. The primary reason to install it is to save on air conditioning costs, as it prevents the loss of heat through the attic. They have been the subject of much controversy, as the claims made by many manufacturers were extreme (up to 100% heat shielding), with the consumer paying high prices for ineffective devices. The authors outline criteria for the consumer to consider when buying radiant warmers and then give installation tips for both new constructions and retrofits.

  10. Pressure detector based on the itinerant-electron metamagnetic transition of La(Fe0.88Si0.12)13Hy

    International Nuclear Information System (INIS)

    The ferromagnetic (FM)-paramagnetic (PM) first-order transition is induced by pressure around room temperature for La(Fe0.88Si0.12)13H1.25 with the Curie temperature TC = 293 K. The spontaneous magnetization at room temperature is significantly decreased due to the phase transition induced by pressure. In addition, the low-field magnetic susceptibility exhibits a response against hydrostatic pressures. From these results, the pressure detection using FM-PM transition has been demonstrated. By dispersing the coarse-grained La(Fe0.88Si0.12)13H1.25 into a column-shaped epoxy resin, the susceptibility change against the unidirectional stress is detected by the inductance of a coil. The inductance response is scarcely changed after 400 cycles of loading. Relating to endurance, the thermal phase stability of hydrides annealed at various temperatures has been investigated. The hydrogen desorption rate obtained from the Arrhenius plots is negligibly small around room temperature, proving that La(Fe0.88Si0.12)13H1.25 has high thermal phase stability over a long period of time.

  11. The ALICE forward multiplicity detector

    International Nuclear Information System (INIS)

    The ALICE experiment is designed to study the properties of hadron and nucleus collisions in a new energy regime at the Large Hadron Collider at CERN. A fundamental observable in such collisions is the multiplicity distribution of charged particles. A forward multiplicity detector has been designed to extend the charged particle multiplicity coverage of the ALICE experiment to pseudorapidities of -3.4<η<-1.7 and 1.7<η<5.0. This detector consists of five rings, each containing 10240 Si strips, divided into sectors comprised of Si sensors bonded and glued to hybrid PC boards equipped with radiation hard preamplifiers. The output of these preamplifiers is multiplexed into custom-made fast ADC chips located directly behind the Si sensors on the detector frame. These ADCs are read out, via optical fibers, to a data acquisition farm of commodity PCs. The design and characteristics of the ALICE Forward Multiplicity Detector will be discussed

  12. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-10-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  13. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-09-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  14. Large lateral photovoltaic effect in µc-SiOx:H/a-Si:H/c-Si p-i-n structure

    Science.gov (United States)

    Qiao, Shuang; Chen, Jianhui; Liu, Jihong; Zhang, Xinhui; Wang, Shufang; Fu, Guangsheng

    2016-03-01

    In this paper, we report on a large lateral photovoltaic effect (LPE) in a hydrogenated microcrystal silicon-oxygen (µc-SiOx:H)-based p-i-n structure. Compared with LPE in a hydrogenated amorphous silicon (a-Si:H)-based p-i-n structure, this structure showed an abnormal current-voltage (I-V) curve with a lower photoelectric conversion efficiency, but exhibited a much higher LPE with the highest position sensitivity of 64.3 mV/mm. We ascribe this to the enhancement of the lateral gradient of excess transmitted carriers induced by increasing both Schottky barrier and p-type layer body conductivity. Our results suggest that this µc-SiOx:H-based p-i-n structure may be a promising candidate for position-sensitive detectors (PSDs). Moreover, our results may also imply that solar cell devices with abnormal I-V curves (or low efficiency) could find their new applications in other aspects.

  15. SiD Letter of Intent

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, H., (Ed.); Burrows, P., (Ed.); Oreglia, M., (Ed.); Berger, E.L.; Guarino, V.; Repond, J.; Weerts, H.; Xia, L.; Zhang, J.; /Argonne, HEP; Zhang, Q.; /Argonne, HEP /Beijing, Inst. High Energy Phys.; Srivastava, A.; /Birla Inst. Tech. Sci.; Butler, J.M.; /Boston U.; Goldstein, Joel; Velthuis, J.; /Bristol U.; Radeka, V.; /Brookhaven; Zhu, R.-Y.; /Caltech.; Lutz, P.; /DAPNIA, Saclay; de Roeck, A.; Elsener, K.; Gaddi, A.; Gerwig, H.; /CERN /Cornell U., LNS /Ewha Women' s U., Seoul /Fermilab /Gent U. /Darmstadt, GSI /Imperial Coll., London /Barcelona, Inst. Microelectron. /KLTE-ATOMKI /Valencia U., IFIC /Cantabria Inst. of Phys. /Louis Pasteur U., Strasbourg I /Durham U., IPPP /Kansas State U. /Kyungpook Natl. U. /Annecy, LAPP /LLNL, Livermore /Louisiana Tech. U. /Paris U., VI-VII /Paris U., VI-VII /Munich, Max Planck Inst. /MIT, LNS /Chicago, CBC /Moscow State U. /Nanjing U. /Northern Illinois U. /Obninsk State Nucl. Eng. U. /Paris U., VI-VII /Strasbourg, IPHC /Prague, Inst. Phys. /Princeton U. /Purdue U. /Rutherford /SLAC /SUNY, Stony Brook /Barcelona U. /Bonn U. /UC, Davis /UC, Santa Cruz /Chicago U. /Colorado U. /Delhi U. /Hawaii U. /Helsinki U. /Indiana U. /Iowa U. /Massachusetts U., Amherst /Melbourne U. /Michigan U. /Minnesota U. /Mississippi U. /Montenegro U. /New Mexico U. /Notre Dame U. /Oregon U. /Oxford U. /Ramon Llull U., Barcelona /Rochester U. /Santiago de Compostela U., IGFAE /Hefei, CUST /Texas U., Arlington /Texas U., Dallas /Tokyo U. /Washington U., Seattle /Wisconsin U., Madison /Wayne State U. /Yale U. /Yonsei U.

    2012-04-11

    This document presents the current status of the Silicon Detector (SiD) effort to develop an optimized design for an experiment at the International Linear Collider. It presents detailed discussions of each of SiD's various subsystems, an overview of the full GEANT4 description of SiD, the status of newly developed tracking and calorimeter reconstruction algorithms, studies of subsystem performance based on these tools, results of physics benchmarking analyses, an estimate of the cost of the detector, and an assessment of the detector R and D needed to provide the technical basis for an optimised SiD.

  16. 减小ITO/PTCDA/P-Si/Al型光电探测器暗电流的方法%Reduction of dark-current of ITO/PTCDA/P-Si/Al photoelectric detector

    Institute of Scientific and Technical Information of China (English)

    刘凤敏; 宋珍; 甘润今

    2005-01-01

    有机/无机同型异质结是一种新型的光电子元器件,由于它有制备工艺简单,一致性和稳定性好,光电转换效率高,频响特性宽等优点,在光电子领域将有广泛的应用前景.将有机半导体材料苝四甲酸二酐淀积在10 Ω·cm的P-Si无机半导体片上,形成有机/无机同型异质结,然后采用各种工艺处理方法有效的降低了它的暗电流,暗电流减小到了10-9A数量级.对降低暗电流的工艺措施和方法进行了分析和讨论.实验结果还表明,ITO/PTCDA/P-Si/Al同型异质结的暗电流主要成分是耗尽区中载流子的产生-复合电流结的反向饱和电流.

  17. Resonant Tunnelling and Storage of Electrons in Si Nanocrystals within a-SiNx/nc-Si/a-SiNx Structures

    Institute of Scientific and Technical Information of China (English)

    WANG Xiang; HUANG Jian; ZHANG Xian-Gao; DING Hong-Lin; YU Lin-Wei; HUANG Xin-Fan; LI Wei; XU Jun; CHEN Kun-Ji

    2008-01-01

    @@ The a-SiNx/nanocrystalline silicon (nc-Si)/a-SiNx sandwiched structures with asymmetric double-barrier are fabricated in a plasma enhanced chemical vapour deposition (PECVD) system on p-type Si substrates. The nc-Si layer in thickness 5nm is fabricated from a hydrogen-diluted silane gas by the layer-by-layer deposition technique. The thicknesses of tunnel and control SiNx layers are 3nm and 20nm,respectively. Frequency-dependent capacitance spectroscopy is used to study the electron tunnelling and the storage in the sandwiched structures.Distinct frequency-dependent capacitance peaks due to electrons tunnelling into the nc-Si dots and capacitance-voltage (C- V) hysteresis characteristic due to electrons storage in the nc-Si dots are observed with the same sample.

  18. 含等离子喷涂ZrO2热障涂层的Ti3XC2(X=Al,Si)性能研究%PROPERTIES OF Ti3XC2(X=Al, Si) WITH PLASMA SPRAYED ZrO2 THERMAL BARRIER COATING

    Institute of Scientific and Technical Information of China (English)

    刘静; 盛洪飞; 张保山; 彭良明

    2011-01-01

    在1450℃真空下保温1.5 h进行热压反应烧结制备了纯度为90%以上的Ti3AlC2和Ti3SiC2层状结构陶瓷,研究了它们的物相组成、微观结构、力学性能及热物理特性,并在2种陶瓷基体上进行了无金属粘结过渡层等离子喷涂ZrO2热障涂层处理,考察了涂层的结合强度与热冲击特性.结果表明,Ti3AlC2和Ti3SiC2基体材料的抗弯强度和断裂韧性分别为536 MPa,7.8 MPa·m1/2和457 MPa,6.8 MPa·m1/2,在25-1000℃温度范围内的平均线膨胀系数分别为8.77×10-6和9.14×10-6/℃,前者的力学性能与热稳定性均优于后者;等离子喷涂后,整体材料的热导率下降幅度达60%以上,涂层与基体结合牢固且具有良好的抗热冲击特性;对2种基体的涂层隔热效应的计算表明,0.3 mm厚ZrO2涂层外表面与内界面的温差分别为341和358℃,可显著提高工件的使用温度.%There has been a great interest in the synthesis and characterization of Ti3AlC2 and Ti3SiC2 lamellar ceramics due to their striking combination of merits of both metals and ceramics, such as good high-temperature strength, excellent oxidation resistance. In this study, dense and high purity polycrystalline Ti3AlC2 and Ti3SiC2 lamellar ceramics were prepared from Ti, Al(Si) and C powders by reactive hot pressing in vacuum at 1450 ℃ for 1.5 h under 30 Mpa. Their phase constitution, mechanical characterization and thermal properties were investigated. In addition, plasma-sprayed monolayer ZrO2 thermal barrier coatings free of metallic transition layer were prepared on the two ceramic substrates. The purity of the Ti3AlC2 and Ti3SiC2 were 91.5% and 90.3%, and the main impurity was TiC. The flexural strength and fracture toughness were 536 Mpa, 7.8 Mpa·m1/2 and 457 Mpa, 6.8 Mpa·m1/2 for Ti3AlC2 and Ti3SiC2, respectively. They took a respective average value of 8.77×10~6 and 9.14×10~6/℃ for the coefficient of thermal expansion (CTE) without remarkable temperature

  19. Potential for reducing the numbers of SiPM readout surfaces of laser-processed X’tal cube PET detectors

    International Nuclear Information System (INIS)

    We are developing a three-dimensional (3D) position-sensitive detector with isotropic spatial resolution, the X’tal cube. Originally, our design consisted of a crystal block for which all six surfaces were covered with arrays of multi-pixel photon counters (MPPCs). In this paper, we examined the feasibility of reducing the number of surfaces on which a MPPC array must be connected with the aim of reducing the complexity of the system. We evaluated two kinds of laser-processed X’tal cubes of 3 mm and 2 mm pitch segments while varying the numbers of the 4 × 4 MPPC arrays down to two surfaces. The sub-surface laser engraving technique was used to fabricate 3D grids into a monolithic crystal block. The 3D flood histograms were obtained by the Anger-type calculation. Two figures of merit, peak-to-valley ratios and distance-to-width ratios, were used to evaluate crystal identification performance. Clear separation was obtained even in the 2-surface configuration for the 3 mm X’tal cube, and the average peak-to-valley ratios and the distance-to-width ratios were 6.7 and 2.6, respectively. Meanwhile, in the 2 mm X’tal cube, the 6-surface configuration could separate all crystals and even the 2-surface case could also, but the flood histograms were relatively shrunk in the 2-surface case, especially on planes parallel to the sensitive surfaces. However, the minimum peak-to-valley ratio did not fall below 3.9. We concluded that reducing the numbers of MPPC readout surfaces was feasible for both the 3 mm and the 2 mm X’tal cubes. (paper)

  20. Infrared detectors

    CERN Document Server

    Rogalski, Antonio

    2010-01-01

    This second edition is fully revised and reorganized, with new chapters concerning third generation and quantum dot detectors, THz detectors, cantilever and antenna coupled detectors, and information on radiometry and IR optics materials. Part IV concerning focal plane arrays is significantly expanded. This book, resembling an encyclopedia of IR detectors, is well illustrated and contains many original references … a really comprehensive book.-F. Sizov, Institute of Semiconductor Physics, National Academy of Sciences, Kiev, Ukraine

  1. Multi-spectral schottky barrier infrared radiation detection array

    International Nuclear Information System (INIS)

    A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array

  2. Use of semiconductor detector c-Si microstrip type in obtaining the digital radiographic imaging of phantoms and biological samples of mammary glands; Empleo de detector semiconductor de c-Si del tipo microbandas en la obtencion de imagenes radiograficas digitales de maniquies y muestras biologicas de mamas

    Energy Technology Data Exchange (ETDEWEB)

    Leyva, A.; Cabal, A.; Pinera, I.; Abreu, Y.; Cruz, C. M. [Centro de Estudios Avanzados y Desarrollo Nuclear, C. Habana, Cuba (Cuba); Montano, L. M.; Diaz, C. C.; Fontaine, M. [IPN, Centro de Investigaciones y Estudios Avanzados, Mexico D. F. (Mexico); Ortiz, C. M. [ISSSTE, Hospital General Tacuba, Clinica de Mama y Gineco-oncologia, Mexico D. F. (Mexico); Padilla, F. [Instituto Superior de Tecnologias y Ciencias Aplicadas, C. Habana, Cuba (Cuba); De la Mora, R. [Centro de Control Estatal de Equipos Medicos, C. Habana, Cuba (Cuba)], e-mail: aleyva@ceaden.edu.cu

    2009-07-01

    The present work synthesizes the experimental results obtained in the characterization of 64 micro strips crystalline silicon detector designed for experiments in high energies physics, with the objective of studying its possible application in advanced medical radiography, specifically in digital mammography and angiography. The research includes the acquisition of two-dimensional radiography of a mammography phantom using the scanning method, and its comparison with similar images simulated mathematically for different X rays sources. The paper also shows the experimental radiography of two biological samples taken from biopsies of mammas, where it is possible to identify the presence of possible pathological lesions. The results reached in this work point positively toward the effective possibility of satisfactorily introducing those advanced detectors in medical digital imaging applications. (Author)

  3. Photon-Assisted Transmission through a Double-Barrier Structure

    Energy Technology Data Exchange (ETDEWEB)

    LYO,SUNGKWUN K.

    2000-06-27

    The authors study multi-photon-assisted transmission of electrons through single-step, single-barrier and double-barrier potential-energy structures as a function of the photon energy and the temperature. Sharp resonances in the spectra of the tunneling current through double-barrier structures are relevant to infra-red detectors.

  4. Semiconductor X-ray detectors

    CERN Document Server

    Lowe, Barrie Glyn

    2014-01-01

    Identifying and measuring the elemental x-rays released when materials are examined with particles (electrons, protons, alpha particles, etc.) or photons (x-rays and gamma rays) is still considered to be the primary analytical technique for routine and non-destructive materials analysis. The Lithium Drifted Silicon (Si(Li)) X-Ray Detector, with its good resolution and peak to background, pioneered this type of analysis on electron microscopes, x-ray fluorescence instruments, and radioactive source- and accelerator-based excitation systems. Although rapid progress in Silicon Drift Detectors (SDDs), Charge Coupled Devices (CCDs), and Compound Semiconductor Detectors, including renewed interest in alternative materials such as CdZnTe and diamond, has made the Si(Li) X-Ray Detector nearly obsolete, the device serves as a useful benchmark and still is used in special instances where its large, sensitive depth is essential. Semiconductor X-Ray Detectors focuses on the history and development of Si(Li) X-Ray Detect...

  5. Optical Detectors

    Science.gov (United States)

    Tabbert, Bernd; Goushcha, Alexander

    Optical detectors are applied in all fields of human activities from basic research to commercial applications in communication, automotive, medical imaging, homeland security, and other fields. The processes of light interaction with matter described in other chapters of this handbook form the basis for understanding the optical detectors physics and device properties.

  6. Differential cross sections measurement of 28Si(p,p/γ)28Si and 29Si(p,p/γ)29Si reactions for PIGE applications

    Science.gov (United States)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.

    2016-03-01

    Differential cross sections for gamma-ray emission from the 28Si(p,p/γ)28Si (Eγ = 1779 keV) and the 29Si(p,p/γ)29Si (Eγ = 1273 keV) nuclear reactions were measured in the energy range of 2.0-3.2 MeV and 2.0-3.0 MeV, respectively. The thin Si targets were prepared by evaporating natural SiO onto self-supporting Ag films. The gamma-rays and backscattered protons were detected simultaneously. An HPGe detector placed at an angle of 90° with respect to beam direction was employed to collect gamma-rays while an ion implanted Si detector placed at a scattering angle of 165° was used to detect backscattered protons. The great advantage of this work is that differential cross sections were obtained with a procedure irrespective of absolute value of the collected beam charge.

  7. The digitisation of the scintillating fibre detector

    CERN Document Server

    Cogneras, E; van Tilburg, J; de Vries, J

    2014-01-01

    In this note the digitisation of the scintillating fibre detector for the LHCb upgrade is described. The steps for transforming the hits generated by the GEANT simulation into a digital signal are given. The main effects of this detector are described in the simulation code for the LHCb upgrade. In particular, the attenuation of the fibres after irradiation, the geometry of the fibres with respect to the SiPM channels, the gain of the SiPM’s, the thermal noise, the noise from afterpulses and spillover, and the clustering are described. The output is given in the same data format as the one that is expected from the final detector.

  8. Tantalum-based diffusion barriers for copper metallization

    OpenAIRE

    Laurila, Tomi

    2001-01-01

    Interfacial reactions between Cu and Si with different Ta-based diffusion barriers are investigated by means of the combined thermodynamic-kinetic and microstructural analysis. The reaction mechanisms and the related microstructures in the Si/Ta/Cu, Si/TaC/Cu and Si/Ta2N/Cu metallization systems are studied experimentally and theoretically by utilizing the ternary Si-Ta-Cu, Si-Ta-C, Si-Ta-N, Ta-C-Cu, and Ta-N-Cu phase diagrams as well as the activity diagrams calculated at different temperatu...

  9. Spectral response of multi-element silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, B.A.; Rossington, C.S.; Chapman, K. [Univ. of California, Berkeley, CA (United States)

    1997-04-01

    Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon Si(Li) and high purity germanium detectors (HPGe) for high count rate, low noise synchrotron x-ray fluorescence applications. One of the major differences between the segmented Si detectors and the commercially available single-element Si(Li) or HPGe detectors is that hundreds of elements can be fabricated on a single Si substrate using standard silicon processing technologies. The segmentation of the detector substrate into many small elements results in very low noise performance at or near, room temperature, and the count rate of the detector is increased many-fold due to the multiplication in the total number of detectors. Traditionally, a single channel of detector with electronics can handle {approximately}100 kHz count rates while maintaining good energy resolution; the segmented detectors can operate at greater than MHz count rates merely due to the multiplication in the number of channels. One of the most critical aspects in the development of the segmented detectors is characterizing the charge sharing and charge loss that occur between the individual detector strips, and determining how these affect the spectral response of the detectors.

  10. SEM analysis of ion implanted SiC

    Energy Technology Data Exchange (ETDEWEB)

    Malherbe, Johan B., E-mail: johan.malherbe@up.ac.za [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Berg, N.G. van der; Botha, A.J.; Friedland, E.; Hlatshwayo, T.T.; Kuhudzai, R.J. [Department of Physics, University of Pretoria, Pretoria 0002 (South Africa); Wendler, E.; Wesch, W. [Institut für Festkörperphysik, Friedrich-Schiller-Universität, 07743 Jena (Germany); Chakraborty, P. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Silveira, E.F. da [Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro (Brazil)

    2013-11-15

    SiC is a material used in two future energy production technologies, firstly as a photovoltaic layer to harness the UV spectrum in high efficient power solar cells, and secondly as a diffusion barrier material for radioactive fission products in the fuel elements of the next generation of nuclear power plants. For both applications, there is an interest in the implantation of reactive and non-reactive ions into SiC and their effects on the properties of the SiC. In this study 360 keV Ag{sup +}, I{sup +} and Xe{sup +} ions were separately implanted into 6H–SiC and in polycrystalline SiC at various substrate temperatures. The implanted samples were also annealed in vacuum at temperatures ranging from 900 °C to 1600 °C for various times. In recent years, there had been significant advances in scanning electron microscopy (SEM) with the introduction of an in-lens detector combined with field emission electron guns. This allows defects in solids, such as radiation damage created by the implanted ions, to be detected with SEM. Cross-sectional SEM images of 6H–SiC wafers implanted with 360 keV Ag{sup +} ions at room temperature and at 600 °C and then vacuum annealed at different temperatures revealed the implanted layers and their thicknesses. A similar result is shown of 360 keV I{sup +} ions implanted at 600 °C into 6H–SiC and annealed at 1600 °C. The 6H–SiC is not amorphized but remained crystalline when implanting at 600 °C. There are differences in the microstructure of 6H–SiC implanted with silver at the two temperatures as well as with reactive iodine ions. Voids (bubbles) are created in the implanted layers into which the precipitation of silver and iodine can occur after annealing of the samples. The crystallinity of the substrate via implantation temperature caused differences in the distribution and size of the voids. Implantation of xenon ions in polycrystalline SiC at 350 °C does not amorphize the substrate as is the case with room

  11. Scintillating fiber detector

    CERN Document Server

    Vozak, Matous

    2016-01-01

    NA61 is one of the physics experiments at CERN dedicated to study hadron states coming from interactions of SPS beams with various targets. To determine the position of a secondary beam, three proportional chambers are placed along the beamline. However, these chambers tend to have slow response. In order to obtain more precise time information, use of another detector is being considered. Fast response and compact size is making scintillation fiber (SciFi) with silicon photomultiplier (Si-PM) read out a good candidate. This report is focused on analysing data from SciFi collected in a test beam at the beginning of July 2016.

  12. Forward Wall Detector

    International Nuclear Information System (INIS)

    The Forward Wall Detector is designed to identify projectile like fragments from heavy ion reactions at CELSIUS storage ring in Uppsala, Sweden. The FWD consist of 96 detection modules covering azimuthal angle from 3.9o to 11.7o with efficiency of 81%. The detection module can be either of phoswitch type (10 mm fast plastic + 80 mm CsI(Tl)) or standard ΔE-E telescope (750 μm Si + 88 mm CsI(Tl)). It is expected to have charge identification up to Z=18, mass resolution for H and He isotopes and energy resolution ∼ 8%. (author)

  13. MS Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

    2005-11-01

    Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

  14. Semi-transparent SiC Schottky diodes for X-ray spectroscopy

    International Nuclear Information System (INIS)

    We describe a novel SiC Schottky diode architecture. The semi-transparent SiC Schottky diode has an 'ultra-thin' (18 nm Ni/Ti) Schottky contact, a gold annular overlayer and a gold corner-contact pad. We show that the new architecture exhibits the same essential characteristics as a more conventional 'thick-contact' Schottky diode (≥100 nm). Such diodes will have a higher efficiency for low-energy (55Fe, 109Cd and 241Am radioactive sources that show these diodes can be used for spectroscopy with promising energy resolution (1.47 keV FWHM at 22 keV) at room temperature (23 oC). The reduction in contact thickness, however, does reduce the barrier height of the new diodes in comparison to those fabricated using the conventional process, and requires a trade-off between the low-energy detection threshold and the noise in the detector

  15. Liposome-siRNA-peptide complexes cross the blood-brain barrier and significantly decrease PrP on neuronal cells and PrP in infected cell cultures.

    Directory of Open Access Journals (Sweden)

    Bruce Pulford

    Full Text Available BACKGROUND: Recent advances toward an effective therapy for prion diseases employ RNA interference to suppress PrP(C expression and subsequent prion neuropathology, exploiting the phenomenon that disease severity and progression correlate with host PrP(C expression levels. However, delivery of lentivirus encoding PrP shRNA has demonstrated only modest efficacy in vivo. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a new siRNA delivery system incorporating a small peptide that binds siRNA and acetylcholine receptors (AchRs, acting as a molecular messenger for delivery to neurons, and cationic liposomes that protect siRNA-peptide complexes from serum degradation. CONCLUSIONS/SIGNIFICANCE: Liposome-siRNA-peptide complexes (LSPCs delivered PrP siRNA specifically to AchR-expressing cells, suppressed PrP(C expression and eliminated PrP(RES formation in vitro. LSPCs injected intravenously into mice resisted serum degradation and delivered PrP siRNA throughout the brain to AchR and PrP(C-expressing neurons. These data promote LSPCs as effective vehicles for delivery of PrP and other siRNAs specifically to neurons to treat prion and other neuropathological diseases.

  16. Photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Va`vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

  17. Photon detectors

    International Nuclear Information System (INIS)

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF2 windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission

  18. SiPM characterisation and quality Assurance for imaging calorimeters

    International Nuclear Information System (INIS)

    Future lepton colliders like the ILC require a new generation of detectors with unprecedented precision. In this context the CALICE collaboration is developing a highly granular ''imaging'' calorimeter consisting out of ca. 8 million scintillating tiles with Silicon Photomultiplier (SiPM) readout. SiPMs are a novel type of solid state photo-detectors with promising properties. A detailed understanding and characterisation of the SiPMs as well as the characterisation and quality assurance of the scintillating tiles is essential for the final detector. In this talk results of the studies on SiPM and tile characterisation and large scale quality assurance are presented.

  19. Modeling of Si-QD Solar Cell in MATLAB

    Directory of Open Access Journals (Sweden)

    S.S. Bohra

    2013-05-01

    Full Text Available In this paper, the modeling and analysis of single bi-layer Si-QD solar cell is addressed. The modeling of solar cell is done in MATLAB. The photo currents are calculated for various Si-QD diameters like 2.5, 3, 3.5 and 4 nm and SiO2 barrier layer thicknesses like 2.5, 2 and 1.5 nm. It has been observed that with the Si-QD diameter, the photo-current increases. On the other hand, photo-current varies conversely with barrier layer thickness due low carrier tunneling probability through barrier.

  20. Pixel detectors

    CERN Document Server

    Passmore, M S

    2001-01-01

    positions on the detector. The loss of secondary electrons follows the profile of the detector and increases with higher energy ions. studies of the spatial resolution predict a value of 5.3 lp/mm. The image noise in photon counting systems is investigated theoretically and experimentally and is shown to be given by Poisson statistics. The rate capability of the LAD1 was measured to be 250 kHz per pixel. Theoretical and experimental studies of the difference in contrast for ideal charge integrating and photon counting imaging systems were carried out. It is shown that the contrast differs and that for the conventional definition (contrast = (background - signal)/background) the photon counting device will, in some cases, always give a better contrast than the integrating system. Simulations in MEDICI are combined with analytical calculations to investigate charge collection efficiencies (CCE) in semiconductor detectors. Different pixel sizes and biasing conditions are considered. The results show charge shari...

  1. Calorimeter detectors

    CERN Document Server

    de Barbaro, P; The ATLAS collaboration

    2013-01-01

    Although the instantaneous and integrated luminosity in HL-LHC will be far higher than the LHC detectors were originally designed for, the Barrel calorimeters of the four experiments are expected to continue to perform well  throughout the Phase II program. The conditions for the End-Cap calorimeters are far more challenging and whilst some detectors will require relatively modest changes, others require far more substantial upgrades. We present the results of longevity and performance studies for the calorimeter systems of the four main LHC experiments and outline the upgrade options under consideration. We include a discussion of the R&D required to make the final technology choices for the upgraded detectors.

  2. MAMA Detector

    Science.gov (United States)

    Bowyer, Stuart

    1998-01-01

    Work carried out under this grant led to fundamental discoveries and over one hundred publications in the scientific literature. Fundamental developments in instrumentation were made including all the instrumentation on the EUVE satellite, the invention of a whole new type of grazing instrument spectrometer and the development of fundamentally new photon counting detectors including the Wedge and Strip used on EUVE and many other missions and the Time Delay detector used on OREFUS and FUSE. The Wedge and Strip and Time Delay detectors were developed under this grant for less than two million dollars and have been used in numerous missions most recently for the FUSE mission. In addition, a fundamentally new type of diffuse spectrometer has been developed under this grant which has been used in instrumentation on the MMSAT spacecraft and the Lewis spacecraft. Plans are underway to use this instrumentation on several other missions as well.

  3. BES detector

    International Nuclear Information System (INIS)

    The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e+e- annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector. (orig.)

  4. Tantalum oxide coatings as candidate environmental barriers

    OpenAIRE

    Moldovan, Monica; Weyant, C. M.; Johnson, D. Lynn; Faber, K. T.

    2004-01-01

    Tantalum (Ta) oxide, due to its high-temperature capabilities and thermal expansion coefficient similar to silicon nitride, is a promising candidate for environmental barriers for silicon (Si) nitride-based ceramics. This paper focuses on the development of plasma-sprayed Ta oxide as an environmental barrier coating for silicon nitride. Using a D-optimal design of experiments, plasma-spray processing variables were optimized to maximize coating density. The effect of processing variables on c...

  5. Review of amorphous silicon based particle detectors: the quest for single particle detection

    Science.gov (United States)

    Wyrsch, N.; Ballif, C.

    2016-10-01

    Hydrogenated amorphous silicon (a-Si:H) is attractive for radiation detectors because of its radiation resistance and processability over large areas with mature Si microfabrication techniques. While the use of a-Si:H for medical imaging has been very successful, the development of detectors for particle tracking and minimum-ionizing-particle detection has lagged, with almost no practical implementation. This paper reviews the development of various types of a-Si:H-based detectors and discusses their respective achievements and limitations. It also presents more recent developments of detectors that could potentially achieve single particle detection and be integrated in a monolithic fashion into a variety of applications.

  6. Influence of layer type and order on barrier properties of multilayer PECVD barrier coatings

    Science.gov (United States)

    Bahroun, K.; Behm, H.; Mitschker, F.; Awakowicz, P.; Dahlmann, R.; Hopmann, Ch

    2014-01-01

    Due to their macromolecular structure, plastics are limited in their scope of application whenever high barrier functionality against oxygen and water vapour permeation is required. One solution is the deposition of thin silicon oxide coatings in plasma-enhanced chemical vapour deposition (PECVD) processes. A way to improve performance of barrier coatings is the use of multilayer structures built from dyad layers, which combine an inorganic barrier layer and an organic intermediate layer. In order to investigate the influence of type and number of dyads on the barrier performance of coated 23 µm PET films, different dyad setups are chosen. The setups include SiOCH interlayers and SiOx-barrier layers deposited using the precursor hexamethyldisiloxane (HMDSO). A single reactor setup driven in pulsed microwave plasma (MW) mode as well as capacitively coupled plasma (CCP) mode is chosen. In this paper the effects of a variation in intermediate layer recipe and stacking order using dyad setups on the oxygen barrier properties of multilayer coatings are discussed with regard to the chemical structure, morphology and activation energy of the permeation process. Changes in surface nano-morphology of intermediate layers have a strong impact on the barrier properties of subsequent glass-like coatings. Even a complete failure of the barrier is observed. Therefore, when depositing multilayer barrier coatings, stacking order has to be considered.

  7. Influence of layer type and order on barrier properties of multilayer PECVD barrier coatings

    International Nuclear Information System (INIS)

    Due to their macromolecular structure, plastics are limited in their scope of application whenever high barrier functionality against oxygen and water vapour permeation is required. One solution is the deposition of thin silicon oxide coatings in plasma-enhanced chemical vapour deposition (PECVD) processes. A way to improve performance of barrier coatings is the use of multilayer structures built from dyad layers, which combine an inorganic barrier layer and an organic intermediate layer. In order to investigate the influence of type and number of dyads on the barrier performance of coated 23 µm PET films, different dyad setups are chosen. The setups include SiOCH interlayers and SiOx-barrier layers deposited using the precursor hexamethyldisiloxane (HMDSO). A single reactor setup driven in pulsed microwave plasma (MW) mode as well as capacitively coupled plasma (CCP) mode is chosen. In this paper the effects of a variation in intermediate layer recipe and stacking order using dyad setups on the oxygen barrier properties of multilayer coatings are discussed with regard to the chemical structure, morphology and activation energy of the permeation process. Changes in surface nano-morphology of intermediate layers have a strong impact on the barrier properties of subsequent glass-like coatings. Even a complete failure of the barrier is observed. Therefore, when depositing multilayer barrier coatings, stacking order has to be considered. (paper)

  8. Two-color infrared detector

    Science.gov (United States)

    Klem, John F; Kim, Jin K

    2014-05-13

    A two-color detector includes a first absorber layer. The first absorber layer exhibits a first valence band energy characterized by a first valence band energy function. A barrier layer adjoins the first absorber layer at a first interface. The barrier layer exhibits a second valence band energy characterized by a second valence band energy function. The barrier layer also adjoins a second absorber layer at a second interface. The second absorber layer exhibits a third valence band energy characterized by a third valence band energy function. The first and second valence band energy functions are substantially functionally or physically continuous at the first interface and the second and third valence band energy functions are substantially functionally or physically continuous at the second interface.

  9. The Mu3e Tile Detector

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Hans Patrick

    2015-05-06

    The Mu3e experiment is designed to search for the lepton flavour violating decay μ→e{sup +}e{sup +}e{sup -} with a sensitivity of one in 10{sup 16} decays. An observation of such a decay would be a clear sign of physics beyond the Standard Model. Achieving the targeted sensitivity requires a high precision detector with excellent momentum, vertex and time resolution. The Mu3e Tile Detector is a highly granular sub-detector system based on scintillator tiles with Silicon Photomultiplier (SiPM) readout, and aims at measuring the timing of the muon decay products with a resolution of better than 100 ps. This thesis describes the development of the Tile Detector concept and demonstrates the feasibility of the elaborated design. In this context, a comprehensive simulation framework has been developed, in order to study and optimise the detector performance. The central component of this framework is a detailed simulation of the SiPM response. The simulation model has been validated in several measurements and shows good agreement with the data. Furthermore, a 16-channel prototype of a Tile Detector module has been constructed and operated in an electron beam. In the beam tests, a time resolution up to 56 ps has been achieved, which surpasses the design goal. The simulation and measurement results demonstrate the feasibility of the developed Tile Detector design and show that the required detector performance can be achieved.

  10. TFA pixel sensor technology for vertex detectors

    OpenAIRE

    Jarron, P.; Moraes, D.; Despeisse, M.; Dissertori, G.; Dunand, S.; Kaplon. J.; Miazza, C.; Shah, Arvind; Viertel, G M.; Wyrsch, Nicolas

    2008-01-01

    Pixel microvertex detectors at the SLHC and a future linear collider face very challenging issues: extreme radiation hardness, cooling design, interconnections density and fabrication cost. As an alternative approach we present a novel pixel detector based on the deposition of a Hydrogenated Amorphous Silicon (a-Si:H) film on top of a readout ASIC. The Thin-Film on ASIC (TFA) technology is inspired by an emerging microelectronic technology envisaged for visible light Active Pixel Sensor (APS)...

  11. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  12. Analysis of Technology Trend on a SiC Semiconductor Radiation Sensor

    International Nuclear Information System (INIS)

    Silicon carbide(SiC) is a promising semiconductor materials by virtue of its chemical and physical stability due to high binding energy of silicon and carbon. This report is for suggestion of domestic research direction based on SiC semiconductor radiation detector by analysis of technological trend on world SiC semiconductor radiation detector research. Crystalline structure and electrical characteristics of SiC semiconductor are presented. To fabricated a SiC semiconductor radiation detector, epitaxial growth and junction technologies are also addressed. Characteristics of a SiC semiconductor radiation detector for charged/uncharged particles are analyzed. Radiation hardness of a SiC semiconductor radiation detector are also included

  13. Effect of W addition on the electroless deposited NiP(W) barrier layer

    International Nuclear Information System (INIS)

    Electroless deposition of NiP, NiWP thin film on p-type Si as the barrier layer to prevent the diffusion of Cu into Si was investigated. The thermal stability of the Si/Ni(W)P/Cu layers were evaluated by measuring the changes of resistance of the samples after annealed at various temperatures. XRD was applied to detect the formation of Cu3Si and evaluate the barrier performance of the layers. The results of XRD of the stacked Si/NiP/Cu, Si/NiWP-1/Cu, Si/NiWP–2/Cu films reveal that Cu atom could diffuse through NiP barrier layer at 450 °C, Cu could hardly diffuse through NiWP layer at 550 °C. This means that with W added in the layer, the barrier performance is improved. Although the resistance of Si/NiWP-1 and Si/NiWP-2 are higher than that of Si/NiP, the resistance of stacked layers of Si/NiWP-1/Cu and Si/NiWP–2/Cu are close to that of Si/NiP/Cu. This means that using NiWP as barrier layer is acceptable.

  14. Visible Blind SiC Array with Low Noise Readout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To date, we have (i) designed and fabricated both common cathode and common anode SiC detector arrays; (ii) designed and fabricated the detector packaging (FPA),...

  15. Fast timing methods for semiconductor detectors. Revision

    International Nuclear Information System (INIS)

    This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter

  16. Development of Readout Interconnections for the Si-W Calorimeter of SiD

    Energy Technology Data Exchange (ETDEWEB)

    Woods, M.; Fields, R.G.; Holbrook, B.; Lander, R.L.; Moskaleva, A.; Neher, C.; Pasner, J.; Tripathi, M.; /UC, Davis; Brau, J.E.; Frey, R.E.; Strom, D.; /Oregon U.; Breidenbach, M.; Freytag, D.; Haller, G.; Herbst, R.; Nelson, T.; /SLAC; Schier, S.; Schumm, B.; /UC, Santa Cruz

    2012-09-14

    The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.

  17. Development of Readout Interconnections for the Si-W Calorimeter of SiD

    CERN Document Server

    Woods, M; Holbrook, B; Lander, R L; Moskaleva, A; Neher, C; Pasner, J; Tripathi, M; Brau, J E; Frey, R E; Strom, D; Breidenbach, M; Freytag, D; Haller, G; Herbst, R; Nelson, T; Schier, S; Schumm, B

    2011-01-01

    The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.

  18. Gallium Nitride Room Temperature α Particle Detectors

    International Nuclear Information System (INIS)

    Gallium Nitride (GaN) room temperature α particle detectors are fabricated and characterized, whose device structure is Schottky diode. The current-voltage (I – V) measurements reveal that the reverse breakdown voltage of the detectors is more than 200 V owing to the consummate fabrication processes, and that the Schottky barrier and ideal factor of the detectors are 0.64 eV and 1.02, respectively, calculated from the thermionic transmission model. 241Am α particles pulse height spectra from the GaN detectors biased at −8 V is obviously one Gauss peak located at channel 44 with the full width at half maximum (FWHM) of 15.87 in channel. One of the main reasons for the relatively wider FWHM is that the air between the detectors and isotope could widen the spectrum

  19. Neutron radiation damage studies on silicon detectors

    International Nuclear Information System (INIS)

    Effects of neutron radiation on electrical properties of Si detectors have been studied. At high neutron fluence (Φn ≥ 1012 n/cm2), C-V characteristics of detectors with high resistivities (ρ ≥ 1 kΩ-cm) become frequency dependent. A two-trap level model describing this frequency dependent effect is proposed. Room temperature anneal of neutron damaged (at LN2 temperature) detectors shows three anneal stages, while only two anneal stages were observed in elevated temperature anneal. 19 refs., 14 figs

  20. Characterization of Si detectors, search for vertex and potentiality of detecting a light charged Higgs boson in the CMS experiment; Caracterisation des detecteurs silicium, recherche de Vertex et etude du potentiel de decouverte d'un boson de Higgs charge leger dans l'experience CMS

    Energy Technology Data Exchange (ETDEWEB)

    Estre, N

    2004-07-01

    The CMS (compact muon solenoid) detector that will be set on the future LHC (large hadron collider) accelerator will enable us to continue our search for the Higgs boson as well as to look for any hint for a new physics beyond the standard model. CMS is composed of an efficient muon detector, an electromagnetic calorimeter and of a tracker with high spatial resolution, this tracker is the topic of this thesis. The tracker will allow an accurate reconstruction of charged-particles trajectories and the reconstruction of the primary interaction vertex. The tracker's technology is based on micro-strip Si detectors, tests performed with the SPS particle beam show that these detectors have an impact reconstruction efficiency greater than 98% and a piling-up rate limited to 6%. The spatial resolution concerning particle trajectories is about 45 {mu}m for an interval of 183 {mu}m between 2 strips. The simulation for the search for a light charged Higgs boson show that an excess of {tau}{nu}{sub {tau}} + bb-bar + qq-bar' events is possible to be observed for any value of tan({beta}) up to M{sub A} = 122 GeV/c{sup 2} during the first year of operation and up to 136 GeV/c{sup 2} afterwards. With the assumption that this event excess is due to the decay of charged Higgs bosons we can state that the assessment of its mass will be possible till m{sub H} = 150 GeV/c{sup 2} with an accuracy of 15 GeV/c{sup 2}. (A.C.)

  1. Diffusion mechanisms in the Fe3Si alloys

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, the possible reasons for the high thermal vacancy concentration and the low migration barriers for the Fe atom diffusion in the stoichiometric D03 structure Fe3Si have been discussed. The high thermal vacancy concentration was attributed to the compression of Fe-Fe atomic pairs and the tension of Fe-Si atomic pairs in Fe75Si25. The deformations (compression or tension) of the atompairs increase the interatomic potentials and thus decrease the enthalpies of vacancy formation. The low migration barriers for the Fe atom diffusion in Fe75Si25 were related to the symmetric property of the triangular barriers. Additionally, it was considered that the Si atoms in Fe3Si could probably migrate via nearest-neighbour jumps without disturbing the long-range order of atomic arrangements, provided that during the diffusion process the residence time on the antistructure sites is very short.

  2. The vertex detector for the Lepton/Photon collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.P.; Boissevain, J.G.; Fox, D.; Hecke, H. van; Jacak, B.V.; Kapustinsky, J.S.; Leitch, M.J.; McGaughey, P.L.; Moss, J.M.; Sondheim, W.E. [Los Alamos National Lab., NM (United States)

    1991-12-31

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two con- centric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity ({nu}) distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed.

  3. The vertex detector for the Lepton/Photon Collaboration

    International Nuclear Information System (INIS)

    The conceptual design of the vertex detector for the Lepton/Photon Collaboration at RHIC is described, including simulations of its expected performance. The design consists of two concentric layers of single-sided Si strips. The expected performance as a multiplicity detector and in measuring the pseudo-rapidity η distribution is discussed as well as the expected vertex finding efficiency and accuracy. Various options which could be used to reduce the cost of the detector are also discussed

  4. Investigation of structural and electrical properties of flat a-Si/c-Si heterostructure fabricated by EBPVD technique

    Energy Technology Data Exchange (ETDEWEB)

    Demiroğlu, D. [Department of Metallurgical and Materials Engineering, Istanbul Technical University, Ayazağa 34469, Istanbul (Turkey); Tatar, B. [Faculty of Arts and Sciences, Department of Physics, Namık Kemal University, Değirmenaltı, Tekirdağ (Turkey); Kazmanli, K.; Urgen, M. [Department of Metallurgical and Materials Engineering, Istanbul Technical University, Ayazağa 34469, Istanbul (Turkey)

    2013-12-16

    Flat amorphous silicon - crystal silicon (a-Si/c-Si) heterostructure were prepared by ultra-high vacuum electron beam evaporation technique on p-Si (111) and n-Si (100) single crystal substrates. Structural analyses were investigated by XRD, Raman and FEG-SEM analysis. With these analyses we determined that at the least amorphous structure shows modification but amorphous structure just protected. The electrical and photovoltaic properties of flat a-Si/c-Si heterojunction devices were investigated with current-voltage characteristics under dark and illumination conditions. Electrical properties of flat a-Si/c-Si heterorojunction; such as barrier height Φ{sub B}, diode ideality factor η were determined from current-voltage characteristics in dark conditions. These a-Si/c-Si heterostructure have good rectification behavior as a diode and exhibit high photovoltaic sensitivity.

  5. Improvement of Interfacial Adhesion Strength and Thermal Stability of Cu/p-SiC:H/SiOC:H Film Stack by Plasma Treatment on the Surface of Cu Film

    International Nuclear Information System (INIS)

    A highly reliable interface of self-aligned barrier CuSiN thin layer between the Cu film and the nano-porous SiC:H (p-SiC:H) capping barrier (k=3.3) has been developed in the present work. With the introduction of self-aligned barrier (SAB) CuSiN between a Cu film and a p-SiC:H capping barrier, the interfacial thermal stability and the adhesion of the Cu/p-SiC:H film are considerably enhanced. A significant improvement of adhesion strength and thermal stability of Cu/p-SiC:H/SiOC:H film stack has been achieved by optimizing the pre-clean step before cap-layer deposition and by forming the CuSiN-like phase. This cap layer on the surface of the Cu can provide a more cohesive interface and effectively suppress Cu atom migration as well.

  6. CLIC Detector Power Requirements

    CERN Document Server

    Gaddi, A

    2013-01-01

    An estimate for the CLIC detector power requirements is outlined starting from the available data on power consumptions of the four LHC experiments and considering the differences between a typical LHC Detector (CMS) and the CLIC baseline detector concept. In particular the impact of the power pulsing scheme for the CLIC Detector electronics on the overall detector consumption is considered. The document will be updated with the requirements of the sub-detector electronics once they are more defined.

  7. The Gamma-Ray Response of Silicon Carbide Radiation Detectors

    International Nuclear Information System (INIS)

    Silicon Carbide (SiC) radiation detectors are being developed for charged-particle, neutron, and gamma-ray detection. SiC is a wide band gap semiconductor that offers several advantages for use as a solid-state radiation detector. Among these are the ability of SiC devices to operate at elevated temperatures and their improved resistance to radiation compared to other semiconductors. SiC charged-particle detectors have been shown to have good energy resolution for alpha particles. Furthermore, pulse heights and full-widths at half-maximum were found to be completely unperturbed by changes in temperature up to 89 C. In subsequent measurements, SiC neutron detectors based on detection of neutron-induced tritons from a juxtaposed 6LiF foil were shown to have a highly linear response to thermal neutron flux in the range from 1.76 x 104 to 3.59 x 1010 cm-2/s in National Institute of Standards and Technology neutron fields. An important attribute of SiC radiation detectors is their ability to operate in and monitor intense gamma-ray fields while in pulse-mode operation

  8. The HERMES Recoil Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Weilin [II. Physikalisches Institut, JLU Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

    2008-07-01

    The HERMES Collaboration at HERA constructed and installed a new Recoil Detector to upgrade the existed spectrometer. This detector is designed to measure recoil protons in hard exclusive processes which provide access to the orbital angular momentum of quarks. The Recoil Detector consists of a silicon detector surrounding the target cell inside the beam vacuum, a scintillating fiber tracker and a photon detector. All three detectors are located inside a solenoidal magnet which provides a 1 T longitudinal magnetic field. The Recoil Detector was installed in January 2006 and data taking lasted until the end of HERA operation in June 2007. Results on the detector performance will be presented here.

  9. MUON DETECTOR

    CERN Multimedia

    F. Gasparini

    DT As announced in the previous Bulletin MU DT completed the installation of the vertical chambers of barrel wheels 0, +1 and +2. 242 DT and RPC stations are now installed in the negative barrel wheels. The missing 8 (4 in YB-1 and 4 in YB-2) chambers can be installed only after the lowering of the two wheels into the UX cavern, which is planned for the last quarter of the year. Cabling on the surface of the negative wheels was finished in May after some difficulties with RPC cables. The next step was to begin the final commissioning of the wheels with the final trigger and readout electronics. Priority was giv¬en to YB0 in order to check everything before the chambers were covered by cables and services of the inner detectors. Commissioning is not easy since it requires both activity on the central and positive wheels underground, as well as on the negative wheels still on the surface. The DT community is requested to commission the negative wheels on surface to cope with a possible lack of time a...

  10. {open_quotes}Pre-residue{close_quotes} light charged particles from {sup 28}Si+{sup 165}Ho and {sup 16}O+{sup 197}Au, {sup 208}Pb fusion

    Energy Technology Data Exchange (ETDEWEB)

    Fineman, B.J.; Brinkmann, K.T.; Caraley, A.L.; Gan, N.; McGrath, R.L.; Velkovska, J.

    1993-10-01

    Proton and alpha particle spectral shapes and multiplicities have been measured in coincidence with evaporation residues from {sup 28}Si+{sup 165}Ho and {sup 16}O + {sup 197}Au, {sup 208}Pb fusion reactions. Our experiments used 145 to 220 MeV {sup 28}Si and 115 and 140 MeV {sup 16}O beams produced with the Stony Brook LINAC. ER`s were separated using an electrostatic deflector and detected with large area surface barrier detectors. Light charged particles were detected at forward and backward angles with fourteen single NaI detectors. In the context of the statistical model, charged particle spectra yield information about emission barriers and compound nucleus equilibrium level densities. These are significant ingredients in calculations determining fission timescales from other observables such as pre-scission neutron multiplicities or fusion-evaporation excitation functions. Results will also be compared to analyses of pre-scission charged particles from similar systems which required barrier reductions to describe measured spectra.

  11. Epitaxial growth of Fe3Si/CaF2/Fe3Si magnetic tunnel junction structures on CaF2/Si(111) by molecular beam epitaxy

    OpenAIRE

    Kobayashi, Ken’ichi; Suemasu, Takashi; Kuwano, Noriyuki; Hara, Daisuke; Akinaga, Hiroyuki

    2007-01-01

    The Fe3Si(24 nm)/CaF2(2 nm)/Fe3Si(12 nm) magnetic tunnel junction (MTJ) structures were grown epitaxially on CaF2/Si(111) by molecular beam epitaxy (MBE). The 12-nm-thick Fe3Si underlayer was grown epitaxially on CaF2/Si(111) at approximately 400 °C; however, the surface of the Fe3Si film was very rough, and thus a lot of pinholes are considered to exist in the 2-nm-thick CaF2 barrier layer. The average roughness (Ra) of the CaF2 barrier layer was 7.8 nm. This problem was overcome by low-temp...

  12. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

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

    Science.gov (United States)

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

    2016-08-01

    Time of flight (TOF) in positron emission tomography (PET) has experienced a revival of interest after its first introduction in the eighties. This is due to a significant progress in solid state photodetectors (SiPMs) and newly developed scintillators (LSO and its derivatives). Latest developments at Fondazione Bruno Kessler (FBK) lead to the NUV-HD SiPM with a very high photon detection efficiency of around 55%. Despite the large area of 4×4 mm2 it achieves a good single photon time resolution (SPTR) of 180±5ps FWHM. Coincidence time resolution (CTR) measurements using LSO:Ce codoped with Ca scintillators yield best values of 73±2ps FWHM for 2×2×3 mm3 and 117±3ps for 2×2×20 mm3 crystal sizes. Increasing the crystal cross-section from 2×2 mm2 to 3×3 mm2 a non negligible CTR deterioration of approximately 7ps FWHM is observed. Measurements with LSO:Ce codoped Ca and LYSO:Ce scintillators with various cross-sections (1×1 mm2 - 4×4 mm2) and lengths (3mm - 30mm) will be a basis for discussing on how the crystal geometry affects timing in TOF-PET. Special attention is given to SiPM parameters, e.g. SPTR and optical crosstalk, and their measured dependency on the crystal cross-section. Additionally, CTR measurements with LuAG:Ce, LuAG:Pr and GGAG:Ce samples are presented and the results are interpreted in terms of their scintillation properties, e.g. rise time, decay time, light yield and emission spectra.

  14. Neutron detectors made from chemically vapor deposited semiconductors

    International Nuclear Information System (INIS)

    In this paper, the authors present the results of investigations on the use of semiconductors deposited by chemical vapor deposition (CVD) for the fabrication of neutron detectors. For this purpose, 20 microm thick hydrogenated amorphous silicon (a-Si:H) pin diodes and 100 microm thick polycrystalline diamond resistive detectors were fabricated. The detectors were coupled to a neutron-charged particle converter: a layer of either gadolinium or boron (isotope 10 enriched) deposited by evaporation. They have demonstrated the capability of such neutron detectors to operate at neutron fluxes ranging from 101 to 106 neutrons/cm2.s. The fabrication of large area detectors for neutron counting or cartography through the use of multichannel reading circuits is discussed. The advantages of these detectors include the ability to produce large area detectors at low cost, radiation hardness (∼ 4 Mrad for a-Si:H and ∼ 100 Mrad for diamond), and for diamond, operation at temperatures up to 500 C. These properties enable the use of these devices for neutron detection in harsh environments. Thermal neutron detection efficiency up to 22% and 3% are expected by coupling a-Si:H diodes and diamond detectors to 3 microm thick gadolinium (isotope 157) and 2 microm thick boron layers, respectively

  15. Niobium Silicon alloys for Kinetic Inductance Detectors

    CERN Document Server

    Calvo, M; Monfardini, A; Benoit, A; Boudou, N; Bourrion, O; Catalano, A; Dumoulin, L; Goupy, J; Sueur, H Le; Marnieros, S

    2013-01-01

    We are studying the properties of Niobium Silicon amorphous alloys as a candidate material for the fabrication of highly sensitive Kinetic Inductance Detectors (KID), optimized for very low optical loads. As in the case of other composite materials, the NbSi properties can be changed by varying the relative amounts of its components. Using a NbSi film with T_c around 1 K we have been able to obtain the first NbSi resonators, observe an optical response and acquire a spectrum in the band 50 to 300 GHz. The data taken show that this material has very high kinetic inductance and normal state surface resistivity. These properties are ideal for the development of KID. More measurements are planned to further characterize the NbSi alloy and fully investigate its potential.

  16. AMPLEX-SiCAL

    International Nuclear Information System (INIS)

    This paper reports on an analog signal processor using commercial 3 μm CMOS technology which has been designed and produced for the silicon luminosity calorimeter SiCAL of the ALEPH experiment. This processor is a modified version of the AMPLEX integrated circuit designed for the inner silicon detector of the UA-2 experiment. The output voltage swing has been increased to more than 5.5 Volt as required for the large dynamic range of 1000 MIPs or 3.8 pC2. A fast analog summation, based on a neural network principle called follower aggregation, computes the average input charges for triggering purposes. The chip contains 16 channels, with a charge amplifier, shaper, track-and-hold stage, multiplexer, fast analog sum and a calibration system. The power consumption of the overall chip is 100 mW. The equivalent noise charge is less than 0.13MIP (0.5 fC rms) for a 50 pF detector capacitance, and the peaking time is about 250ns

  17. New class of biological detectors for WIMPs

    CERN Document Server

    Drukier, A K; Chonofsky, M; Church, G M; Fagaly, R L; Freese, K; Lopez, A; Sano, T; Savage, C; Wong, W P

    2014-01-01

    Weakly Interacting Massive Particles (WIMPs) may constitute a large fraction of the matter in the Universe. There are excess events in the data of DAMA/LIBRA, CoGeNT, CRESST-II, and recently CDMS-Si, which could be consistent with WIMP masses of approximately 10 GeV/c2. However, for MDM > 10 GeV/c2 null results of the CDMS-Ge, XENON, and LUX detectors may be in tension with the potential detections for certain dark matter scenarios and assuming a certain light response. We propose the use of a new class of biological dark matter (DM) detectors to further examine this light dark matter hypothesis, taking advantage of new signatures with low atomic number targets, Two types of biological DM detectors are discussed here: DNA-based detectors and enzymatic reactions (ER) based detectors. In the case of DNA-based detectors, we discuss a new implementation. In the case of ER detectors, there are four crucial phases of the detection process: a) change of state due to energy deposited by a particle; b) amplification d...

  18. Compound semiconductor GaAs and CdTe nuclear radiation detectors

    International Nuclear Information System (INIS)

    The preparation technology and characteristics of semi-insulating bulk single crystal GaAs surface-barrier detectors and single crystal CdTe surface-barrier detectors are described. The spectroscopic performance of the detectors for γ-rays from 125I, 241Am and 57Co at room temperature is given. The influence of the magnitude of forward resistive induced by ohmic contacts and of the surface passivation and aging in the fabrication process of surface-barrier detectors on the performance of the detectors is discussed. Finally, the influence of the fabrication technology of ohmic contacts and selected materials, such as Ni-Ge-Au and In-Ge-Ag, on the performance of the detectors is also studied

  19. Simulation of Multilayer Silicon Thin Films Growth on Si(111) Surface

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The homoepitaxial growth of multilayer Si thin film on Si(111) surfaces was simulated by Monte Carlo (MC) method with realistic growth model and physical parameters. Special emphasis was placed on revealing the influence of the Ehrlich-Schwoebel (ES) barrier on the growth modes and morphologies. It is evident that there exists the ES barrier during multilayer Si thin film growth on Si (111) surface, which is deduced from the incomplete layer-by-layer growth process in the realistic experiments. The ES barrier EB=0.1~0.125 eV is estimated from the three-dimensional (3D) MC simulation and compared with the experimental results.

  20. Fast neutron spectrometry using thick threshold detectors

    Directory of Open Access Journals (Sweden)

    Idiri Z.

    2012-04-01

    Full Text Available This paper discusses the use of thick threshold activation detectors for the characterization of low intensity neutron fields. This technique has been applied to the determination of the spectral emission of a low activity (37 GBq Am-Be source. The reaction rates induced by the neutrons emitted by this source in different thick metallic targets (Al, Si, Fe, In have been measured in the following reactions: 27Al(n,p27Mg, 27Al(n,α24Na, 28Si(n,p28Al, 56Fe(n,p56Mn, 115In(n, n′115mIn and 115In(n, γ116mIn. Each measured reaction rate corresponding to a threshold detector response depends on the spectral emission of the source via a correcting factor. This factor, which takes into account the source detector geometry, the neutron attenuation and diffusion by the detectors, has been determined by Monte Carlo simulation using MCNP5 code. The spectral emission of the neutron source has been generated from the response matrix of the threshold detectors by using different neutron spectrum unfolding methods (Stayn'l, Gravel and Maxed. A fairly good agreement with the assumed ISO spectrum has been achieved.

  1. ????????????-???????????? ?????? ? ????????????? ????????? ???????? ??????? Ge-Si

    OpenAIRE

    ????????, ?. ?.; ???????????, ?. ?.; ???, ?. ?.; ?????????, ?. ?.

    2003-01-01

    ?????????? ????????????-???????????? ?????? ? ????????????? ????????? (??) ???????? ??????? GexSi1-x (? = 0.01 - 0.03) p-???? ??????????? ? ?????????????? ????????? (4,2 ... 300 K). ????????????? ????? ?????????? ?? ?????-??? ?? ?????????????????? ??. ??????????? ?????????? ??????? ????????? ??????? ??? ?????????? ??. ???????? ?????????? ??????????? ?'???-??????? ?? ??????????????? ? ?? Ge-Si ??????? ???????? ?????-?????????? ?? ???????? ???????????. ?????????? ?????????? ??????????? ???...

  2. Interwell coupling effect in Si/SiGe quantum wells grown by ultra high vacuum chemical vapor deposition

    Directory of Open Access Journals (Sweden)

    Loh Ter-Hoe

    2007-01-01

    Full Text Available AbstractSi/Si0.66Ge0.34coupled quantum well (CQW structures with different barrier thickness of 40, 4 and 2 nm were grown on Si substrates using an ultra high vacuum chemical vapor deposition (UHV-CVD system. The samples were characterized using high resolution x-ray diffraction (HRXRD, cross-sectional transmission electron microscopy (XTEM and photoluminescence (PL spectroscopy. Blue shift in PL peak energy due to interwell coupling was observed in the CQWs following increase in the Si barrier thickness. The Si/SiGe heterostructure growth process and theoretical band structure model was validated by comparing the energy of the no-phonon peak calculated by the 6 + 2-bandk·pmethod with experimental PL data. Close agreement between theoretical calculations and experimental data was obtained.

  3. The SuperCDMS SNOLAB Detector Tower

    Science.gov (United States)

    Aramaki, Tsuguo

    2016-08-01

    The SuperCDMS collaboration is moving forward with the design and construction of SuperCDMS SNOLAB, where the initial deployment will include ˜ 30 kg of Ge and ˜ 5 kg of Si detectors. Here, we will discuss the associated cryogenic cold hardware required for the detector readout. The phonon signals will be read out with superconducting quantum interference device arrays and the ionization signals will use high electron mobility transistor amplifiers operating at 4 K. A number of design challenges exist regarding the required wiring complex impedance, noise pickup, vibration, and thermal isolation. Our progress to date will be presented.

  4. Infrared detectors for space applications

    Science.gov (United States)

    Cardimona, D. A.; Huang, D. H.; Cowan, V.; Morath, C.

    2011-05-01

    Two of the main requirements for space situational awareness are to locate and identify dim and/or distant objects. At the Air Force Research Laboratory's Space Vehicles Directorate, we are investigating how nanostructured metal surfaces can produce plasmon-enhanced fields to address the first function. We are also investigating quantum interference effects in semiconductor quantum dots inside photonic crystal cavities to address the amplification of weak signals. To address the second function of identification of space objects, we are investigating a wavelength-tunable detector scheme that involves a coupled double quantum well structure with a thin middle barrier between the two wells. The photocurrent from this structure will be swept out with a lateral bias. In order to eliminate the diffraction loss of incident photons by a surface grating structure for the z-polarization required in normal quantum well infrared photodetector structures, we will grow an array of self-organized quantum dots buried in one of the quantum wells of a symmetric double quantum well structure. In this paper, we will first describe the requirements for detectors in space, then we will describe our work in the above topics, and finally we will briefly mention our forays into other areas of quantum-structured detectors for use in space.

  5. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk......Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... analysis with operational safety management....

  6. Extremal surface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Netta; Wall, Aron C. [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

    2014-03-13

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy.

  7. Safety- barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2008-01-01

    Safety-barrier diagrams and the related so-called 'bow-tie' diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation of safety-barrier diagrams to other methods such as fault...... trees and Bayesian networks is discussed. A simple method for quantification of safety-barrier diagrams is proposed. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk analysis with operational safety management....

  8. Fast neutron spectrometry using thick threshold detectors

    OpenAIRE

    Idiri Z.; Allab M.; Boukeffoussa K.; Medkour Ishak-Boushaki G.

    2012-01-01

    This paper discusses the use of thick threshold activation detectors for the characterization of low intensity neutron fields. This technique has been applied to the determination of the spectral emission of a low activity (37 GBq) Am-Be source. The reaction rates induced by the neutrons emitted by this source in different thick metallic targets (Al, Si, Fe, In) have been measured in the following reactions: 27Al(n,p)27Mg, 27Al(n,α)24Na, 28Si(n,p)28Al, 56Fe(n,p)56Mn, 115In(n, n′)115mIn and 11...

  9. 金硅共晶键合在微机械Golay-cell红外探测器中的应用%Au/Si Eutectic Bonding Application for Micromachining Golay-cell Infrared Detector

    Institute of Scientific and Technical Information of China (English)

    赵林林; 徐晨; 杨道虹; 霍文晓; 赵慧; 沈光地

    2005-01-01

    利用硅微机械加工技术制备微机械Golay-cell红外探测器硅可动敏感薄膜,探测器气室由带薄膜结构硅片与带孔结构硅片键合密闭形成,气室中敏感气体吸收红外辐射而膨胀,使硅膜产生形变,借助硅膜电极板与金属电极板形成的平行板电容反映该形变变化量.运用Si/Ti/Au/Au/Ti/Si实现对探测器的金/硅共晶键合封装,形成气室,制备出探测器样品并初步得到响应.该键合方法能够进行选择区域键合,实验证明键合强度达到体硅强度.

  10. Investigation of Dark-Count-Less Lu2(SiO4)O-Multipixel-Photon Detector and Its Application to Photon Counting X-ray Computed Tomography Using Iodine Media

    Science.gov (United States)

    Sato, Eiichi; Oda, Yasuyuki; Kodama, Hajime; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira

    2013-09-01

    X-ray photons are detected using a Lu2(SiO4)O [LSO] single-crystal scintillator with a decay time of 40 ns and a multipixel photon counter (MPPC). The photocurrent from the MPPC is amplified by a high-speed current-voltage amplifier with an 80 MHz-gain-band operational amplifier, and the 200-ns-width event pulses are sent to a multichannel analyzer (MCA) to measure X-ray spectra. The MPPC was driven in the pre-Geiger mode at a bias voltage of 70.7 V and a temperature of 23 °C. Photon-counting computed tomography (PC-CT) is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by linear scanning at a tube current of 1.5 mA. In PC-CT, the event pulse height is dispersed using a 7-ns-delay comparator. The exposure time for obtaining a tomogram is 10 min with scan steps of 0.5 mm and rotation steps of 1.0°. At a tube voltage of 80 kV, the maximum count rate is 250 kcps. We carry out PC-CT using iodine media and confirm the energy-dispersive effect with changes in the lower level voltage of event pulses using a comparator.

  11. Localization of Si/SiO2 Interface States: Properties and Physical Implications

    Science.gov (United States)

    Koiller, Belita; Dusko, Amintor; Saraiva, Andre

    2013-03-01

    Interface states (IS) form spontaneously at some semiconductor-barrier interfaces and they may improve or hinder electronic control and coherence for semiconductor-based qubits. Intrinsic Si/SiO2 IS and its hybridization to the Si bulk states were recently investigated within tight binding (TB) models. From the simplest model (1D), new insights emerge regarding the IS's energy and hybridization with the band states. In this work the 1D TB Hamiltonian is further explored, here within a Green's function formalism. The problem is solved exactly via a decimation technique based on renormalization group ideas. The IS thus obtained are strictly related to the junction of two semi-infinite chains modeling the Si material and the SiO2 barrier, excluding possible contributions from parameters (e.g. chain length) previously invoked. We obtain the energy of IS as well as the exponential longer (shorter) localization lengths into the Si (barrier) material. The IS may be probed experimentally by an external electric field, which modulates the capacitance of the system, or by the spacing between the two lowest levels, related to the valley splitting. Work partially supported by FAPERJ, CNPq, CAPES.

  12. Self healing mechanism in thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Kochubey, V.; Sloof, W.G. [Delft Univ. of Technology (Netherlands)

    2008-07-01

    During service damage in terms of small cracks develops in thermal barrier coatings (TBC), composed of partially yttria stabilized zirconia (PYSZ), and applied to gas turbine components made of Ni-base superalloys coated with an aluminide diffusion or MCrAlY overlay coating. Growth and coalescence of these microcracks results in cracks that run parallel to the interface with the substrate leading to failure by delamination of the TBC. A mechanism is proposed to heal the micro-cracks in a TBC by introducing MoSi{sub 2} particles. Upon high temperature expose in air, in the range of 1200 C, MoSi{sub 2} forms amorphous SiO{sub 2} that can fill micro-cracks, thereby restoring the integrity of the TBC. (orig.)

  13. Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution

    OpenAIRE

    Cassell, Ron

    2009-01-01

    Simulated calorimeter performance in the SiD detector is examined. The software calibration procedures are described, as well as the perfect pattern recognition PFA reconstruction. Performance of the SiD calorimeters is summarized with jet energy resolutions from calorimetry only, perfect pattern recognition and the SiD PFA algorithm. Presented at LCWS08[1].

  14. Anisotropic Lithium Insertion Behavior in Silicon Nanowires: Binding Energy, Diffusion Barrier, and Strain Effect

    KAUST Repository

    Zhang, Qianfan

    2011-05-19

    Silicon nanowires (SiNWs) have recently been shown to be promising as high capacity lithium battery anodes. SiNWs can be grown with their long axis along several different crystallographic directions. Due to distinct atomic configuration and electronic structure of SiNWs with different axial orientations, their lithium insertion behavior could be different. This paper focuses on the characteristics of single Li defects, including binding energy, diffusion barriers, and dependence on uniaxial strain in [110], [100], [111], and [112] SiNWs. Our systematic ab initio study suggests that the Si-Li interaction is weaker when the Si-Li bond direction is aligned close to the SiNW long axis. This results in the [110] and [111] SiNWs having the highest and lowest Li binding energy, respectively, and it makes the diffusion barrier along the SiNW axis lower than other pathways. Under external strain, it was found that [110] and [001] SiNWs are the most and least sensitive, respectively. For diffusion along the axial direction, the barrier increases (decreases) under tension (compression). This feature results in a considerable difference in the magnitude of the energy barrier along different diffusion pathways. © 2011 American Chemical Society.

  15. Optimizing The Organic/Inorganic Barrier Structure For Flexible Plastic Substrate Encapsulation

    Directory of Open Access Journals (Sweden)

    Yi-Chiuan Lin

    2012-07-01

    Full Text Available A multilayered barrier structure stacked with organosilicon and silicon oxide (SiOx films consecutively prepared using plasma-enhanced chemical vapor deposition (PECVD was developed to encapsulate flexible plastic substrate. The evolution on the residual internal stress, structural quality of the organosilicon/SiOx multilayered structure as well as its adhesion to the substrate were found to correlate closely with the thickness of the inset organosilicon layer. Due to the significant discrepancy in the thermal expansion coefficient between the substrate and SiOx film, the thickness of the organosilicon layer deposited onto the substrate and SiOx film thus was crucial to optimize the barrier property of the organosilicon/SiOx structure. The organosilicon/SiOx barrier structure possessed a lowest residual compressive stress and quality adhesion to the substrate was achieved from engineering the organosilicon layer thickness in the multilayered structure. The relaxation of the residual internal stress in the barrier structure led to a dense SiOx film as a consequence of the enhancement in the Si-O-Si networks and thereby resulted in the reduction of the water vapor permeation. Accordingly, a water vapor transmission rate (WVTR below 1 × 10-2 g/m2 /day being potential for the application on the flexible optoelectronic device packaging was achievable from the 3-pairs organosilicon/SiOx multilayered structure deposited onto the polyethylene terephthalate (PET substrate.

  16. GADRAS Detector Response Function.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J.; Harding, Lee; Thoreson, Gregory G; Horne, Steven M.

    2014-11-01

    The Gamma Detector Response and Analysis Software (GADRAS) applies a Detector Response Function (DRF) to compute the output of gamma-ray and neutron detectors when they are exposed to radiation sources. The DRF is fundamental to the ability to perform forward calculations (i.e., computation of the response of a detector to a known source), as well as the ability to analyze spectra to deduce the types and quantities of radioactive material to which the detectors are exposed. This document describes how gamma-ray spectra are computed and the significance of response function parameters that define characteristics of particular detectors.

  17. The MINOS Detectors

    CERN Document Server

    Grashorn, A H E W

    2005-01-01

    The Main Injector Neutrino Oscillation Search (MINOS) experiment's primary goal is the precision measurement of the neutrino oscillation parameters in the atmospheric neutrino sector. This long-baseline experiment uses Fermilab's NuMI beam, measured with a Near Detector at Fermilab, and again 735 km later using a Far Detector in the Soudan Mine Underground Lab in northern Minnesota. The detectors are magnetized iron/scintillator calorimeters. The Far Detector has been operational for cosmic ray and atmospheric neutrino data from July of 2003, the Near Detector from September 2004, and the NuMI beam started in early 2005. This poster presents details of the two detectors.

  18. The TALE Tower Detector

    Science.gov (United States)

    Bergman, D. R.

    The TA Low Energy Extension will include a Tower FluorescenceDetector. Extensive air showers at the lowest usful energies for fluorescence detectors will in general be close to the detector. This requires viewing all elevation angles to be able to reconstruct showers. The TALE Tower Detector, operating in conjunction with other TALE detectors will view elevation angles up to above 70 degrees, with an azimuthal coverage of about 90 degrees. Results from a prototype mirror operated in conjunction with the HiRes detector will also be presented.

  19. Pt silicide/poly-Si Schottky diodes as temperature sensors for bolometers

    OpenAIRE

    Yuryev, V. A.; Chizh, K. V.; Chapnin, V.A.; Mironov, S.A.; Dubkov, V. P.; Uvarov, O. V.; Kalinushkin, V. P.; Senkov, V. M.; Nalivaiko, O. Y.; Novikau, A. G.; Gaiduk, P. I.

    2015-01-01

    Platinum silicide Schottky diodes formed on films of polycrystalline Si doped by phosphorus are demonstrated to be efficient and manufacturable CMOS-compatible temperature sensors for microbolometer detectors of radiation. Thin-film platinum silicide/poly-Si diodes have been produced by a CMOS-compatible process on artificial Si$_3$N$_4$/SiO$_2$/Si(001) substrates simulating the bolometer cells. Layer structure and phase composition of the original Pt/poly-Si films and the Pt silicide/poly-Si...

  20. Status of the digital pixel array detector for protein crystallography

    CERN Document Server

    Datte, P; Beuville, E; Endres, N; Druillole, F; Luo, L; Millaud, J E; Xuong, N H

    1999-01-01

    A two-dimensional photon counting digital pixel array detector is being designed for static and time resolved protein crystallography. The room temperature detector will significantly enhance monochromatic and polychromatic protein crystallographic through-put data rates by more than three orders of magnitude. The detector has an almost infinite photon counting dynamic range and exhibits superior spatial resolution when compared to present crystallographic phosphor imaging plates or phosphor coupled CCD detectors. The detector is a high resistivity N-type Si with a pixel pitch of 150x150 mu m, and a thickness of 300 mu m, and is bump bonded to an application specific integrated circuit. The event driven readout of the detector is based on the column architecture and allows an independent pixel hit rate above 1 million photons/s/pixel. The device provides energy discrimination and sparse data readout which yields minimal dead-time. This type of architecture allows a continuous (frameless) data acquisition, a f...

  1. TFA pixel sensor technology for vertex detectors

    International Nuclear Information System (INIS)

    Pixel microvertex detectors at the SLHC and a future linear collider face very challenging issues: extreme radiation hardness, cooling design, interconnections density and fabrication cost. As an alternative approach we present a novel pixel detector based on the deposition of a Hydrogenated Amorphous Silicon (a-Si:H) film on top of a readout ASIC. The Thin-Film on ASIC (TFA) technology is inspired by an emerging microelectronic technology envisaged for visible light Active Pixel Sensor (APS) devices. We present results obtained with a-Si:H sensor films deposited on a glass substrate and on ASIC, including the radiation hardness of this material up to a fluence of 3.5x1015 p/cm2

  2. Drift Chambers detectors; Detectores de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Martinez laso, L.

    1989-07-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

  3. Application of Geiger-mode photosensors in Cherenkov detectors

    Science.gov (United States)

    Gamal, Ahmed; Paul, Bühler; Michael, Cargnelli; Roland, Hohler; Johann, Marton; Herbert, Orth; Ken, Suzuki

    2011-05-01

    Silicon-based photosensors (SiPMs) working in the Geiger-mode represent an elegant solution for the readout of particle detectors working at low-light levels like Cherenkov detectors. Especially the insensitivity to magnetic fields makes this kind of sensors suitable for modern detector systems in subatomic physics which are usually employing magnets for momentum resolution. We are characterizing SiPMs of different manufacturers for selecting sensors and finding optimum operating conditions for given applications. Recently we designed and built a light concentrator prototype with 8×8 cells to increase the active photon detection area of an 8×8 SiPM (Hamamatsu MPPC S10931-100P) array. Monte Carlo studies, measurements of the collection efficiency, and tests with the MPPC were carried out. The status of these developments are presented.

  4. Method of production of silicon surface-barrier radiation detector

    International Nuclear Information System (INIS)

    For improved resistance of the gold electrode to abrasive wear, the silicon carrier plate is etched using, e.g., a mixture of nitric, hydrofluoric and glacial acetic acids. Following oxidation in the presence of air, the gold electrode is deposited by at least three-fold vacuum deposition using a mask while the silicon plate is heated to within 80 and 160 degC, with a dwell of 4 to 12 hours between the individual deposition operations. (M.D.)

  5. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis

  6. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    Science.gov (United States)

    Dulloo, Abdul R.; Ruddy, Frank H.; Seidel, John G.; Petrović, Bojan

    2001-07-01

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis.

  7. X-ray detectors in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Spahn, Martin, E-mail: martin.spahn@siemens.com [Siemens AG, Healthcare Sector, Imaging and Therapy Systems, 91301 Forchheim (Germany)

    2013-12-11

    Healthcare systems are subject to continuous adaptation, following trends such as the change of demographic structures, the rise of life-style related and chronic diseases, and the need for efficient and outcome-oriented procedures. This also influences the design of new imaging systems as well as their components. The applications of X-ray imaging in the medical field are manifold and have led to dedicated modalities supporting specific imaging requirements, for example in computed tomography (CT), radiography, angiography, surgery or mammography, delivering projection or volumetric imaging data. Depending on the clinical needs, some X-ray systems enable diagnostic imaging while others support interventional procedures. X-ray detector design requirements for the different medical applications can vary strongly with respect to size and shape, spatial resolution, frame rates and X-ray flux, among others. Today, integrating X-ray detectors are in common use. They are predominantly based on scintillators (e.g. CsI or Gd{sub 2}O{sub 2}S) and arrays of photodiodes made from crystalline silicon (Si) or amorphous silicon (a-Si) or they employ semiconductors (e.g. Se) with active a-Si readout matrices. Ongoing and future developments of X-ray detectors will include optimization of current state-of-the-art integrating detectors in terms of performance and cost, will enable the usage of large size CMOS-based detectors, and may facilitate photon counting techniques with the potential to further enhance performance characteristics and foster the prospect of new clinical applications.

  8. Tin Can Radiation Detector.

    Science.gov (United States)

    Crull, John L.

    1986-01-01

    Provides instructions for making tin can radiation detectors from empty aluminum cans, aluminum foil, clear plastic, copper wire, silica gel, and fine, unwaxed dental floss put together with tape or glue. Also provides suggestions for activities using the detectors. (JN)

  9. Forward tracking detectors

    Indian Academy of Sciences (India)

    Klaus Mönig

    2007-11-01

    Forward tracking is an essential part of a detector at the international linear collider (ILC). The requirements for forward tracking are explained and the proposed solutions in the detector concepts are shown.

  10. Permeation barrier performance of Hot Wire-CVD grown silicon-nitride films treated by argon plasma

    OpenAIRE

    Majee, S.; Cerqueira, M. F.; Tondelier, D.; Vanel, J. C.; Geffroy, B.; Bonnassieux, Y.; Alpuim, P.; Bourée, J. E.

    2015-01-01

    In this work SiNx thin films have been deposited by Hot-Wire Chemical Vapor Deposition (HW-CVD) technique to be used as encapsulation barriers for flexible organic electronic devices fabricated on polyethylene terephthalate (PET) substrates. First results of SiNx multilayers stacked and stacks of SiNx single-layers (50 nm each) separated by an Ar-plasma surface treatment are reported. The encapsulation barrier properties of these different multilayers are assessed using the electrical calcium...

  11. SIRI - A proposal for a multi-detector ΔE-E particle telescope

    International Nuclear Information System (INIS)

    The CACTUS detector system which is mounted on the 90o beam line of the Oslo Cyclotron consists of 28 NaI and 2 Ge detectors in combination with 8 Si particle telescopes. The Si particle telescopes are however based on an old technology with a geometrical lay-out that prohibits further increase in efficiency. In this report a replacement of the old system in the form of 64 telescopes based on silicon strip detectors is proposed. For the planned system called SIRI (Silicon Ring), the detectors are located on a ring around the target, covering the angles between 30o and 60o relative to the beam direction. The planned detector system will increase detector efficiency of charged particles by a factor 8. The design and construction of the new detector system is described and discussed. 8 refs., 9 figs., 4 tabs

  12. JADE muon detector

    Energy Technology Data Exchange (ETDEWEB)

    Allison, J.; Armitage, J.C.M.; Baines, J.T.M.; Ball, A.H.; Bamford, G.; Barlow, R.J.; Bowdery, C.K.; Chrin, J.T.M.; Duerdoth, I.P.; Glendinning, I.; Greenshaw, T.; Hassard, J.F.; Hill, P.; King, B.T.; Loebinger, F.K.; Macbeth, A.A.; McCann, H.; Mercer, D.; Mills, H.E.; Murphy, P.G.; Prosper, H.B.; Rowe, P.; Stephens, K.

    1985-08-01

    The JADE muon detector consists of 618 planar drift chambers interspersed between layers of hadron absorber. This paper gives a detailed description of the construction and operation of the detector as a whole and discusses the properties of the drift chambers. The muon detector has been operating successfully at PETRA for five years. (orig.).

  13. Gas filled detectors

    International Nuclear Information System (INIS)

    The main types of gas filled nuclear detectors: ionization chambers, proportional counters, parallel-plate avalanche counters (PPAC) and microstrip detectors are described. New devices are shown. A description of the processes involved in such detectors is also given. (K.A.) 123 refs.; 25 figs.; 3 tabs

  14. Graphene vertical hot-electron terahertz detectors

    International Nuclear Information System (INIS)

    We propose and analyze the concept of the vertical hot-electron terahertz (THz) graphene-layer detectors (GLDs) based on the double-GL and multiple-GL structures with the barrier layers made of materials with a moderate conduction band off-set (such as tungsten disulfide and related materials). The operation of these detectors is enabled by the thermionic emissions from the GLs enhanced by the electrons heated by incoming THz radiation. Hence, these detectors are the hot-electron bolometric detectors. The electron heating is primarily associated with the intraband absorption (the Drude absorption). In the frame of the developed model, we calculate the responsivity and detectivity as functions of the photon energy, GL doping, and the applied voltage for the GLDs with different number of GLs. The detectors based on the cascade multiple-GL structures can exhibit a substantial photoelectric gain resulting in the elevated responsivity and detectivity. The advantages of the THz detectors under consideration are associated with their high sensitivity to the normal incident radiation and efficient operation at room temperature at the low end of the THz frequency range. Such GLDs with a metal grating, supporting the excitation of plasma oscillations in the GL-structures by the incident THz radiation, can exhibit a strong resonant response at the frequencies of several THz (in the range, where the operation of the conventional detectors based on A3B5 materials, in particular, THz quantum-well detectors, is hindered due to a strong optical phonon radiation absorption in such materials). We also evaluate the characteristics of GLDs in the mid- and far-infrared ranges where the electron heating is due to the interband absorption in GLs.

  15. Type II superlattice technology for LWIR detectors

    Science.gov (United States)

    Klipstein, P. C.; Avnon, E.; Azulai, D.; Benny, Y.; Fraenkel, R.; Glozman, A.; Hojman, E.; Klin, O.; Krasovitsky, L.; Langof, L.; Lukomsky, I.; Nitzani, M.; Shtrichman, I.; Rappaport, N.; Snapi, N.; Weiss, E.; Tuito, A.

    2016-05-01

    SCD has developed a range of advanced infrared detectors based on III-V semiconductor heterostructures grown on GaSb. The XBn/XBp family of barrier detectors enables diffusion limited dark currents, comparable with MCT Rule-07, and high quantum efficiencies. This work describes some of the technical challenges that were overcome, and the ultimate performance that was finally achieved, for SCD's new 15 μm pitch "Pelican-D LW" type II superlattice (T2SL) XBp array detector. This detector is the first of SCD's line of high performance two dimensional arrays working in the LWIR spectral range, and was designed with a ~9.3 micron cut-off wavelength and a format of 640 x 512 pixels. It contains InAs/GaSb and InAs/AlSb T2SLs, engineered using k • p modeling of the energy bands and photo-response. The wafers are grown by molecular beam epitaxy and are fabricated into Focal Plane Array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridization, under-fill, and back-side polishing. The FPA has a quantum efficiency of nearly 50%, and operates at 77 K and F/2.7 with background limited performance. The pixel operability of the FPA is above 99% and it exhibits a stable residual non uniformity (RNU) of better than 0.04% of the dynamic range. The FPA uses a new digital read-out integrated circuit (ROIC), and the complete detector closely follows the interfaces of SCD's MWIR Pelican-D detector. The Pelican- D LW detector is now in the final stages of qualification and transfer to production, with first prototypes already integrated into new electro-optical systems.

  16. Thermal stability of nanocrystalline W-Ti diffusion barrier thin films

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Nanocrystalline W-Ti diffusion barrier thin films with different phase structures and Cu/barrier/Si multilayer structures were deposited on p-type Si(100) substrates by DC magnetron sputtering.These films were annealed at different temperatures for 1 h.The diffusion barrier properties and thermal stability were studied using four-probe tester(FPP),XRD,AFM,XPS,FESEM,and HRTEM.The experimental results showed that the films were stable up to 700℃.When the annealing temperature was increased,the Cu and Ti atoms began to react and CuTi3 was formed.In addition,the high resistance Cu3Si was formed due to inter-diffusion between the Si and Cu atoms which made the surface rougher and caused the sheet resistance to increase abruptly.At the same time,failure mechanism of the nanocrystalline W-Ti diffusion barrier thin films during annealing process was also discussed.

  17. Preresidue'' light charged particles from [sup 28]Si+[sup 165]Ho, [sup 16]O+[sup 197]Au, and [sup 16]O+[sup 208]Pb fusion

    Energy Technology Data Exchange (ETDEWEB)

    Fineman, B.J.; Brinkmann, K.; Caraley, A.L.; Gan, N.; McGrath, R.L.; Velkovska, J. (Physics Department, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States))

    1994-10-01

    Proton and [alpha]-particle spectral shapes and multiplicities have been measured in coincidence with evaporation residues from 145 to 220 MeV [sup 28]Si+[sup 165]Ho and 115 and 140 MeV [sup 16]O+[sup 197]Au,[sup 208]Pb fusion reactions. Evaporation residues were separated using an electrostatic deflector and detected with large area surface barrier detectors. Light charged particles were detected at forward and backward angles with 14 single NaI detectors. In the context of the statistical model, the charged particle spectra provide information about the shapes and level densities of the emitting systems. Deformed emitters are inferred, and to a varying degree, an energy-dependent level density parameter is compatible with the data in each of the three cases. Implications for current fusion and fission dynamics studies are discussed.

  18. Performance comparison of scintillators for alpha particle detectors

    Science.gov (United States)

    Morishita, Yuki; Yamamoto, Seiichi; Izaki, Kenji; Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio

    2014-11-01

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd2Si2O7 (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM

  19. Energy band design for p-type tensile strained Si/SiGe multi-quantum well infrared photodetector

    Institute of Scientific and Technical Information of China (English)

    LI Jin-tao; CHEN Song-yan; QI Dong-feng; HUANG Wei; LI Cheng; LAI Hong-kai

    2011-01-01

    The band structure of the confined states is calculated for Si/SiGe multi-quantum well infrared photodetector (M-QWIP). The influence of the Ge component in pseudosubstrate on the energy band structure of Si/Si0.54Ce0.46 multi-quantum wells (MQWs) is investigated. It is found that the high energy levels in the MQWs move up while the low energy levels move down as the Ge component in psendosubstrate increases. The influence of the barrier width on the energy band structure of MQWs is also studied based on the 6 × 6 k-p method. The results show that the Si barrier between 5 nm and 10 nm is optimized to enhance the intersubband absorption in the MQWs.

  20. Multilayer coatings for flexible high-barrier materials

    Science.gov (United States)

    Vaško, Karol; Noller, Klaus; Mikula, Milan; Amberg-Schwab, Sabine; Weber, Ulrike

    2009-06-01

    A multilayer, flexible, and transparent high-barrier system based on flexible plastic foils, polyethyleneterephthalate (PET) and ethylene-tetrafluoroethylene-copolymer (ETFE), combined with vacuum-deposited, inorganic SiOx layers and hybrid ORMOCER® varnish layers were prepared in different orders on a semiproduction level. Barrier properties of prepared systems, as water vapour transmission (WVTR) and oxygen transmission (OTR), were measured and studied in connection with surface energy, surface topography, and water vapour adsorption properties. Correlations among layers sequence, barrier properties, and other parameters are presented, including some basic principles of permeation of substances through multilayer barrier systems. A combination of several inorganic and hybrid varnish layers is necessary to achieve the technological demands from a barrier standpoint. It is easier to suppress the oxygen transport than the water transport, due to the additional active penetration of water through hydrogen bonds and silanol creations at oxide interfaces, capillary condensation, and swelling with high internal pressure, leading to new defects.