A time-of-flight system for the external target facility

NASA Astrophysics Data System (ADS)

Zhang, Xue-Heng; Yu, Yu-Hong; Sun, Zhi-Yu; Mao, Rui-Shi; Wang, Shi-Tao; Zhou, Yong; Yan, Duo; Liu, Long-Xiang

2013-05-01

A time-of-flight system with a plastic scintillator coupled to photomultipliers is developed for the external target facility (ETF). This system can satisfy the requirement of an ultrahigh vacuum (~10-9 mbar), a high counting rate (~106 particles per second) and a magnetic field environment. In the beam test experiment, a total time resolution of 580 ps FWHM was obtained for the whole system, and nuclei with a mass of up to 80 could be identified using this system.

Readout architecture based on the use of Silicon PhotoMultiplier (SiPM, or MMPC)

NASA Astrophysics Data System (ADS)

Marteau, J.; Carlus, B.; Gardien, S.; Girerd, C.; Ianigro, J.-C.; Montorio, J.-L.; Gibert, D.; Nicollin, F.

2012-04-01

The DIAPHANE project is pluri-disciplinary collaboration between particle physicists and geophysicists to perform the tomography of large geological structure mainly devoted to the study of active volcanoes. The detector used for this tomography, hereafter referred to as telescope, uses a standard, robust, cost-effective and well-known technology based on solid plastic scintillator readout by photomultiplier(s). The first generation of those telescopes, presently running in the Mont-Terri underground laboratory (St-Ursanne, Switzerland) and on the active volcano of La Soufrière (Guadeloupe, Lesser Antilles, France), uses Hamamatsu H8804-200mod photomultipliers. We present an upgrade of the readout architecture based on the use of Silicon PhotoMultiplier (SiPM, or MMPC) which allows to simplify the optical connections w.r.t. the present design and to benefit from the high photo-dectection efficiency of the SiPM. To ensure an effective increase in the muon detection efficiency one has to optimize the first trigger level and find the best compromise between photostatistics and the tails of the dark noise contributions. Several readout architectures, based or not on dedicated ASICs, are discussed and compared in this article.

Testing and simulation of silicon photomultiplier readouts for scintillators in high-energy astronomy and solar physics

NASA Astrophysics Data System (ADS)

Bloser, P. F.; Legere, J. S.; Bancroft, C. M.; Jablonski, L. F.; Wurtz, J. R.; Ertley, C. D.; McConnell, M. L.; Ryan, J. M.

2014-11-01

Space-based gamma-ray detectors for high-energy astronomy and solar physics face severe constraints on mass, volume, and power, and must endure harsh launch conditions and operating environments. Historically, such instruments have usually been based on scintillator materials due to their relatively low cost, inherent ruggedness, high stopping power, and radiation hardness. New scintillator materials, such as LaBr3:Ce, feature improved energy and timing performance, making them attractive for future astronomy and solar physics space missions in an era of tightly constrained budgets. Despite this promise, the use of scintillators in space remains constrained by the volume, mass, power, and fragility of the associated light readout device, typically a vacuum photomultiplier tube (PMT). In recent years, silicon photomultipliers (SiPMs) have emerged as promising alternative light readout devices that offer gains and quantum efficiencies similar to those of PMTs, but with greatly reduced mass and volume, high ruggedness, low voltage requirements, and no sensitivity to magnetic fields. In order for SiPMs to replace PMTs in space-based instruments, however, it must be shown that they can provide comparable performance, and that their inherent temperature sensitivity can be corrected for. To this end, we have performed extensive testing and modeling of a small gamma-ray spectrometer composed of a 6 mm×6 mm SiPM coupled to a 6 mm×6 mm ×10 mm LaBr3:Ce crystal. A custom readout board monitors the temperature and adjusts the bias voltage to compensate for gain variations. We record an energy resolution of 5.7% (FWHM) at 662 keV at room temperature. We have also performed simulations of the scintillation process and optical light collection using Geant4, and of the SiPM response using the GosSiP package. The simulated energy resolution is in good agreement with the data from 22 keV to 662 keV. Above ~1 MeV, however, the measured energy resolution is systematically worse than the simulations. This discrepancy is likely due to the high input impedance of the readout board front-end electronics, which introduces a non-linear saturation effect in the SiPM for large light pulses. Analysis of the simulations indicates several additional steps that must be taken to optimize the energy resolution of SiPM-based scintillator detectors.

Contamination study

NASA Astrophysics Data System (ADS)

Johnson, R. Barry; Herren, Kenneth A.

1990-09-01

The time dependence of the angular reflectance from molecularly contaminated optical surfaces in the Vacuum Ultraviolet (VUV) is measured. The light scattering measurements are accomplished in situ on optical surfaces in real time during deposition of molecular contaminants. The measurements are taken using non-coherent VUV sources with the predominant wavelengths being the Krypton resonance lines at 1236 and 1600 A. Detection of the scattered light is accomplished using a set of three solar blind VUV photomultipliers. An in-plane VUV BRDF (Bidirectional Reflectance Distribution Functions) experiment is described and details of the ongoing program to characterize optical materials exposed to the space environment is reported.

The Lewis Research Center geomagnetic substorm simulation facility

NASA Technical Reports Server (NTRS)

Berkopec, F. D.; Stevens, N. J.; Sturman, J. C.

1977-01-01

A simulation facility was established to determine the response of typical spacecraft materials to the geomagnetic substorm environment and to evaluate instrumentation that will be used to monitor spacecraft system response to this environment. Space environment conditions simulated include the thermal-vacuum conditions of space, solar simulation, geomagnetic substorm electron fluxes and energies, and the low energy plasma environment. Measurements for spacecraft material tests include sample currents, sample surface potentials, and the cumulative number of discharges. Discharge transients are measured by means of current probes and oscilloscopes and are verified by a photomultiplier. Details of this facility and typical operating procedures are presented.

Calculation of the time resolution of the J-PET tomograph using kernel density estimation

NASA Astrophysics Data System (ADS)

Raczyński, L.; Wiślicki, W.; Krzemień, W.; Kowalski, P.; Alfs, D.; Bednarski, T.; Białas, P.; Curceanu, C.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Gorgol, M.; Hiesmayr, B.; Jasińska, B.; Kamińska, D.; Korcyl, G.; Kozik, T.; Krawczyk, N.; Kubicz, E.; Mohammed, M.; Pawlik-Niedźwiecka, M.; Niedźwiecki, S.; Pałka, M.; Rudy, Z.; Rundel, O.; Sharma, N. G.; Silarski, M.; Smyrski, J.; Strzelecki, A.; Wieczorek, A.; Zgardzińska, B.; Zieliński, M.; Moskal, P.

2017-06-01

In this paper we estimate the time resolution of the J-PET scanner built from plastic scintillators. We incorporate the method of signal processing using the Tikhonov regularization framework and the kernel density estimation method. We obtain simple, closed-form analytical formulae for time resolution. The proposed method is validated using signals registered by means of the single detection unit of the J-PET tomograph built from a 30 cm long plastic scintillator strip. It is shown that the experimental and theoretical results obtained for the J-PET scanner equipped with vacuum tube photomultipliers are consistent.

Gamma-ray blind beta particle probe

DOEpatents

Weisenberger, Andrew G.

2001-01-01

An intra-operative beta particle probe is provided by placing a suitable photomultiplier tube (PMT), micro channel plate (MCP) or other electron multiplier device within a vacuum housing equipped with: 1) an appropriate beta particle permeable window; and 2) electron detection circuitry. Beta particles emitted in the immediate vicinity of the probe window will be received by the electron multiplier device and amplified to produce a detectable signal. Such a device is useful as a gamma insensitive, intra-operative, beta particle probe in surgeries where the patient has been injected with a beta emitting radiopharmaceutical. The method of use of such a device is also described, as is a position sensitive such device.

A method to stabilise the performance of negatively fed KM3NeT photomultipliers

NASA Astrophysics Data System (ADS)

Adrián-Martínez, S.; Ageron, M.; Aiello, S.; Albert, A.; Ameli, F.; Anassontzis, E. G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Avgitas, T.; Barbarino, G.; Barbarito, E.; Baret, B.; Barrios-Martí, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Beurthey, S.; van Beveren, V.; Beverini, N.; Biagi, S.; Biagioni, A.; Billault, M.; Bondì, M.; Bormuth, R.; Bouhadef, B.; Bourlis, G.; Bourret, S.; Boutonnet, C.; Bouwhuis, M.; Bozza, C.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Cacopardo, G.; Caillat, L.; Calamai, M.; Calvo, D.; Capone, A.; Caramete, L.; Cecchini, S.; Celli, S.; Champion, C.; Cherubini, S.; Chiarella, V.; Chiarelli, L.; Chiarusi, T.; Circella, M.; Classen, L.; Cobas, D.; Cocimano, R.; Coelho, J. A. B.; Coleiro, A.; Colonges, S.; Coniglione, R.; Cordelli, M.; Cosquer, A.; Coyle, P.; Creusot, A.; Cuttone, G.; D'Amato, C.; D'Amico, A.; D'Onofrio, A.; De Bonis, G.; De Sio, C.; Di Capua, F.; Di Palma, I.; Distefano, C.; Donzaud, C.; Dornic, D.; Dorosti-Hasankiadeh, Q.; Drakopoulou, E.; Drouhin, D.; Durocher, M.; Eberl, T.; Eichie, S.; van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Favaro, M.; Fermani, P.; Ferrara, G.; Frascadore, G.; Furini, M.; Fusco, L. A.; Gal, T.; Galatà, S.; Garufi, F.; Gay, P.; Gebyehu, M.; Giacomini, F.; Gialanella, L.; Giordano, V.; Gizani, N.; Gracia, R.; Graf, K.; Grégoire, T.; Grella, G.; Grmek, A.; Guerzoni, M.; Habel, R.; Hallmann, S.; van Haren, H.; Harissopulos, S.; Heid, T.; Heijboer, A.; Heine, E.; Henry, S.; Hernández-Rey, J. J.; Hevinga, M.; Hofestädt, J.; Hugon, C. M. F.; Illuminati, G.; James, C. W.; Jansweijer, P.; Jongen, M.; de Jong, M.; Kadler, M.; Kalekin, O.; Kappes, A.; Katz, U. F.; Keller, P.; Kieft, G.; Kießling, D.; Koffeman, E. N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Lamare, P.; Leisos, A.; Leonora, E.; Clark, M. Lindsey; Liolios, A.; Llorens Alvarez, C. D.; Lo Presti, D.; Löhner, H.; Lonardo, A.; Lotze, M.; Loucatos, S.; Maccioni, E.; Mannheim, K.; Manzali, M.; Margiotta, A.; Margotti, A.; Marinelli, A.; Mariš, O.; Markou, C.; Martínez-Mora, J. A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K. W.; Michael, T.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miraglia, A.; Mollo, C. M.; Mongelli, M.; Morganti, M.; Moussa, A.; Musico, P.; Musumeci, M.; Nicolau, C. A.; Olcina, I.; Olivetto, C.; Orlando, A.; Orzelli, A.; Pancaldi, G.; Paolucci, A.; Papaikonomou, A.; Papaleo, R.; Păvălaš, G. E.; Peek, H.; Pellegrini, G.; Pellegrino, C.; Perrina, C.; Pfutzner, M.; Piattelli, P.; Pikounis, K.; Poma, G. E.; Popa, V.; Pradier, T.; Pratolongo, F.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Racca, C.; Raffaelli, F.; Randazzo, N.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Rossi, C.; Rovelli, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sánchez García, A.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Santonocito, D.; Sapienza, P.; Schimmel, F.; Schmelling, J.; Schnabel, J.; Sciacca, V.; Sedita, M.; Seitz, T.; Sgura, I.; Simeone, F.; Sipala, V.; Spisso, B.; Spurio, M.; Stavropoulos, G.; Steijger, J.; Stellacci, S. M.; Stransky, D.; Taiuti, M.; Tayalati, Y.; Terrasi, F.; Tézier, D.; Theraube, S.; Timmer, P.; Töonnis, C.; Trasatti, L.; Travaglini, R.; Trovato, A.; Tsirigotis, A.; Tzamarias, S.; Tzamariudaki, E.; Vallage, B.; Van Elewyck, V.; Vermeulen, J.; Versari, F.; Vicini, P.; Viola, S.; Vivolo, D.; Volkert, M.; Wiggers, L.; Wilms, J.; de Wolf, E.; Zachariadou, K.; Zani, S.; Zornoza, J. D.; Zúñiga, J.

2016-12-01

The KM3NeT research infrastructure, currently under construction in the Mediterranean Sea, will host neutrino telescopes for the identification of neutrino sources in the Universe and for studies of the neutrino mass hierarchy. These telescopes will house hundreds of thousands of photomultiplier tubes that will have to be operated in a stable and reliable fashion. In this context, the stability of the dark counts has been investigated for photomultiplier tubes with negative high voltage on the photocathode and held in insulating support structures made of 3D printed nylon material. Small gaps between the rigid support structure and the photomultiplier tubes in the presence of electric fields can lead to discharges that produce dark count rates that are highly variable. A solution was found by applying the same insulating varnish as used for the high voltage bases directly to the outside of the photomultiplier tubes. This transparent conformal coating provides a convenient and inexpensive method of insulation.

Electronics of the data acquisition system of the DANSS detector based on silicon photomultipliers

NASA Astrophysics Data System (ADS)

Svirida, D.

2018-01-01

The electronics of the data acquisition system based on silicon photomultipliers is briefly described. The elements and modules of the system were designed and constructed at ITEP especially for the DANSS detector. Examples of digitized signals obtained with the presented electronic modules and selected results on processing of the DANSS engineering data-taking run in spring 2016 are given.

A new detector concept for silicon photomultipliers

NASA Astrophysics Data System (ADS)

Sadigov, A.; Ahmadov, F.; Ahmadov, G.; Ariffin, A.; Khorev, S.; Sadygov, Z.; Suleymanov, S.; Zerrouk, F.; Madatov, R.

2016-07-01

A new design and principle of operation of silicon photomultipliers are presented. The new design comprises a semiconductor substrate and an array of independent micro-phototransistors formed on the substrate. Each micro-phototransistor comprises a photosensitive base operating in Geiger mode and an individual micro-emitter covering a small part of the base layer, thereby creating, together with this latter, a micro-transistor. Both micro-emitters and photosensitive base layers are connected with two respective independent metal grids via their individual micro-resistors. The total value of signal gain in the proposed silicon photomultiplier is a result of both the avalanche gain in the base layer and the corresponding gain in the micro-transistor. The main goals of the new design are: significantly lower both optical crosstalk and after-pulse effects at high signal amplification, improve speed of single photoelectron pulse formation, and significantly reduce the device capacitance.

Determination of Optimum Operating Parameters of Single-Electron Photomultiplier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lukichev, A.A.; Shalyapin, A.L.; Shul'gin, B.V.

1986-06-01

This paper presents a procedure for determining the effective quantum yield and average gain of the dynode system of a photomultiplier. An objective performance figure, the extrapolated count response, is introduced. The results for FEU-142 photomultiplier studies are given. The radiation source used in the studies was a PRK-2 mercury-vapor lamp with a regulated power supply. The recorder was a pulse analyzer based on a UNO-4096-90, which was equipped with BPA-2-95, BPV-2-90, and UVTs-2-90 units. The amplifier used a KP303V transistor and a 140UD1B operational amplifier.

Measurement device for high-precision spectral transmittance of solar blind filter

NASA Astrophysics Data System (ADS)

Wang, Yan; Qian, Yunsheng; Lv, Yang; Feng, Cheng; Liu, Jian

2017-02-01

In order to measure spectral transmittance of solar-blind filter ranging from ultraviolet to visible light accurately, a high-precision filter transmittance measuring system based on the ultraviolet photomultiplier is developed. The calibration method is mainly used to measure transmittance in this system, which mainly consists of an ultraviolet photomultiplier as core of the system and a lock-in amplifier combined with an optical modulator as the aided measurement for the system. The ultraviolet photomultiplier can amplify the current signal through the filter and have the characteristics of low dark current and high luminance gain. The optical modulator and the lock-in amplifier can obtain the signal from the photomultiplier and inhibit dark noise and spurious signal effectively. Through these two parts, the low light passing through the filters can be detected and we can calculate the transmittance by the optical power detected. Based on the proposed system, the limit detection of the transmittance can reach 10-12, while the result of the conventional approach is merely 10-6. Therefore, the system can make an effective assessment of solar blind ultraviolet filters.

The LED and fiber based calibration system for the photomultiplier array of SNO+

NASA Astrophysics Data System (ADS)

Seabra, L.; Alves, R.; Andringa, S.; Bradbury, S.; Carvalho, J.; Clark, K.; Coulter, I.; Descamps, F.; Falk, L.; Gurriana, L.; Kraus, C.; Lefeuvre, G.; Maio, A.; Maneira, J.; Mottram, M.; Peeters, S.; Rose, J.; Sinclair, J.; Skensved, P.; Waterfield, J.; White, R.; Wilson, J.; SNO+ Collaboration

2015-02-01

A new external LED/fiber light injection calibration system was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. The goal of the calibration system is to allow an accurate and regular measurement of the photomultiplier array's performance, while minimizing the risk of radioactivity ingress. The choice in SNO+ was to use a set of optical fiber cables to convey into the detector the light pulses produced by external LEDs. The quality control was carried out using a modified test bench that was used in QC of optical fibers for TileCal/ATLAS. The optical fibers were characterized for transmission, timing and angular dispersions. This article describes the setups used for the characterization and quality control of the system based on LEDs and optical fibers and their results.

The tip/tilt tracking sensor based on multi-anode photo-multiplier tube

NASA Astrophysics Data System (ADS)

Ma, Xiao-yu; Rao, Chang-hui; Tian, Yu; Wei, Kai

2013-09-01

Based on the demands of high sensitivity, precision and frame rate of tip/tilt tracking sensors in acquisition, tracking and pointing (ATP) systems for satellite-ground optical communications, this paper proposes to employ the multiple-anode photo-multiplier tubes (MAPMTs) in tip/tilt tracking sensors. Meanwhile, an array-type photon-counting system was designed to meet the requirements of the tip/tilt tracking sensors. The experiment results show that the tip/tilt tracking sensors based on MAPMTs can achieve photon sensitivity and high frame rate as well as low noise.

R&D of a pioneering system for a high resolution photodetector: The VSiPMT

NASA Astrophysics Data System (ADS)

Barbato, F. C. T.; Barbarino, G.; Campajola, L.; Di Capua, F.; Mollo, C. M.; Valentini, A.; Vivolo, D.

2017-12-01

The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists in replacing the classical dynode chain with a special SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and the stability are among the most attractive features of the VSiPMT.We now present the progress on the realization of a 1-in. prototype and the preliminary tests we are performing on it.

Development of a Liquefied Noble Gas Time Projection Chamber

NASA Astrophysics Data System (ADS)

Lesser, Ezra; White, Aaron; Aidala, Christine

2015-10-01

Liquefied noble gas detectors have been used for various applications in recent years for detecting neutrinos, neutrons, photons, and potentially dark matter. The University of Michigan is developing a detector with liquid argon to produce scintillation light and ionization electrons. Our data collection method will allow high-resolution energy measurement and spatial reconstruction of detected particles by using multi-pixel silicon photomultipliers (SiPM) and a cylindrical time projection chamber (TPC) with a multi-wire endplate. We have already designed a liquid argon condenser and purification unit surrounded by an insulating vacuum, constructed circuitry for temperature and pressure sensors, and created software to obtain high-accuracy sensor readouts. The status of detector development will be presented. Funded through the Michigan Memorial Phoenix Project.

Silicon Photo-Multiplier Readouts for Scintillators in High-Energy Astronomy

NASA Technical Reports Server (NTRS)

Bloser, Peter F.; Legere, Jason S.; Bancroft, Christopher M.; McConnell, Mark L.; Ryan, James M.

2008-01-01

New scintillator materials have recently been shown to hold great potential for low-cost, reliable gamma-ray detectors in high-energy astronomy. New devices for the detection of scintillation light promise to make scintillator-based instruments even more attractive by reducing mass and power requirements,in particular, silicon photo-multipliers (SiPMs) are starting to become commercially available that offer gains and quantum efficiencies similar to those of photo-multiplier tubes (PMTs), but with greatly reduced mass, high ruggedness, low voltage requirements, and no sensitivity to magnetic fields. We have conducted laboratory tests of a sample of commercially available SiPMs coupled to LaBr3;Ce, a scintillator of relevance to to future high-energy astrophysics missions. We present results for gamma-ray spectroscopy. compare the SiPM performance to that of a PMT, and discuss the extent to which SiPMs offer significant advantages for scintillator-based space missions.

Description of the Role of Shot Noise in Spectroscopic Absorption and Emission Measurements with Photodiode and Photomultiplier Tube Detectors: Information for an Instrumental Analysis Course

ERIC Educational Resources Information Center

McClain, Robert L.; Wright, John C.

2014-01-01

A description of shot noise and the role it plays in absorption and emission measurements using photodiode and photomultiplier tube detection systems is presented. This description includes derivations of useful forms of the shot noise equation based on Poisson counting statistics. This approach can deepen student understanding of a fundamental…

Gating characteristics of photomultiplier tubes for Lidar applications

NASA Technical Reports Server (NTRS)

Barrick, J. D. W.

1986-01-01

A detector test facility was developed and applied in the evaluation and characterization of lidar detectors in support of the multipurpose airborne differential absorption lidar (DIAL) system based at the Langley Research Center (LaRC). A performance data base of various detector configurations available to the DIAL system was obtained for optimum lidar detector selection. Photomultiplier tubes (PMT's) with multialkaline and bialkaline photocathodes were evaluated in voltage-divider networks (bases) by using either the focusing electrode or dynodes as a gating mechanism. Characteristics used for detector evaluation included gain stability, signal rise time, and the ability to block unwanted high light levels.

Scintillator tiles read out with silicon photomultipliers

NASA Astrophysics Data System (ADS)

Pooth, O.; Radermacher, T.; Weingarten, S.; Weinstock, L.

2015-10-01

A detector prototype based on a fast plastic scintillator read out with silicon photomultipliers is presented. All studies have been done with cosmic muons and focus on parameter optimization such as coupling the SiPM to the scintillator or wrapping the scintillator with reflective material. The prototype shows excellent results regarding the light-yield and offers a detection efficiency of 99.5% with a signal purity of 99.9% for cosmic muons.

Recent development on the realization of a 1-inch VSiPMT prototype

NASA Astrophysics Data System (ADS)

Barbato, F. C. T.; Barbarino, G.; Campajola, L.; Di Capua, F.; Mollo, C. M.; Valentini, A.; Vivolo, D.

2017-03-01

The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a revolutionary hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists in replacing the classical dynode chain with a SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and great stability are among the most attractive features of the VSiPMT. In order to realize such a device we first studied the feasibility of this detector both from theoretical and experimental point of view, by implementing a Geant4-based simulation and studying the response of a special non-windowed MPPC by Hamamatsu with an electron beam. Thanks to this result Hamamatsu realized two VSiPMT industrial prototypes with a photocathode of 3mm diameter. We present the progress on the realization of a 1-inch prototype and the preliminary tests we are performing on it.

System for the measurement of ultra-low stray light levels. [determining the adequacy of large space telescope systems

NASA Technical Reports Server (NTRS)

Wyman, C. L.; Griner, D. B.; Hurd, W. A.; Shelton, G. B.; Hunt, G. H.; Fannin, B. B.; Brealt, R. P.; Hawkins, C. A. (Inventor)

1978-01-01

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus.

Ultra-fast photon counting with a passive quenching silicon photomultiplier in the charge integration regime

NASA Astrophysics Data System (ADS)

Zhang, Guoqing; Lina, Liu

2018-02-01

An ultra-fast photon counting method is proposed based on the charge integration of output electrical pulses of passive quenching silicon photomultipliers (SiPMs). The results of the numerical analysis with actual parameters of SiPMs show that the maximum photon counting rate of a state-of-art passive quenching SiPM can reach ~THz levels which is much larger than that of the existing photon counting devices. The experimental procedure is proposed based on this method. This photon counting regime of SiPMs is promising in many fields such as large dynamic light power detection.

Waveform digitization for high resolution timing detectors with silicon photomultipliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ronzhin, A.; Albrow, M. G.; Los, S.

2012-03-01

The results of time resolution studies with silicon photomultipliers (SiPMs) read out with high bandwidth constant fraction discrimination electronics were presented earlier [1-3]. Here we describe the application of fast waveform digitization readout based on the DRS4 chip [4], a switched capacitor array (SCA) produced by the Paul Scherrer Institute, to further our goal of developing high time resolution detectors based on SiPMs. The influence of the SiPM signal shape on the time resolution was investigated. Different algorithms to obtain the best time resolution are described, and test beam results are presented.

Development of compact particle detectors for space based instruments

NASA Astrophysics Data System (ADS)

Barner, Lindsey; Grove, Andrew; Mohler, Jacob; Sisson, Caleb; Roth, Alex; Kryemadhi, Abaz

2017-01-01

The Silicon Photomultipliers (SiPMs) are new photon-detectors which have been increasingly used in particle physics. Their small size, good single photon resolution, simple readout, and immunity to magnetic fields offers benefits compared to traditional photomultipliers. LYSO and CeBr3 crystals are relatively new scintillators with high stopping power, very good light yield and fast decay time. The response of these detectors to low energy gamma rays will be presented. NASA Pennsylvania Space Grant Consortium.

Advanced Sensors Boost Optical Communication, Imaging

NASA Technical Reports Server (NTRS)

2009-01-01

Brooklyn, New York-based Amplification Technologies Inc. (ATI), employed Phase I and II SBIR funding from NASA s Jet Propulsion Laboratory to forward the company's solid-state photomultiplier technology. Under the SBIR, ATI developed a small, energy-efficient, extremely high-gain sensor capable of detecting light down to single photons in the near infrared wavelength range. The company has commercialized this technology in the form of its NIRDAPD photomultiplier, ideal for use in free space optical communications, lidar and ladar, night vision goggles, and other light sensing applications.

Estimation of the Lyman-α signal of the EFILE diagnostic under static or radiofrequency electric field in vacuum

NASA Astrophysics Data System (ADS)

Carlo, POGGI; Théo, GUILLAUME; Fabrice, DOVEIL; Laurence, CHÉRIGIER-KOVACIC

2018-07-01

The electric field induced Lyman-α emission diagnostic aims to provide a non intrusive and precise measurement of the electric field in plasma, using a beam of hydrogen atoms prepared in the metastable 2s state. The metastable particles are obtained by means of a proton beam extracted from a hydrogen plasma source, and neutralised by interaction with vaporised caesium. When a 2s atom enters a region where an electric field is present, it undergoes a transition to the 2p state (Stark mixing). It then quickly decays to the ground level, emitting Lyman-α radiation, which is collected by a photomultiplier. The 2s\\to 2p transition rate is proportional to the square of the magnitude of the electric field, and depends on the field oscillation frequency (with peaks around 1 GHz). By measuring the intensity of the Lyman-α radiation emitted by the beam it is possible to determine the magnitude of the field in a defined region. In this work, an analysis of the behaviour of the diagnostic under static or radiofrequency electric field is presented. Electric field simulations obtained with a finite element solver of Maxwell equations, combined with theoretical calculations of the Stark mixing transition rate, are used to develop a model for the interpretation of photomultiplier data. This method shows good agreement with experimental results for the static field case, and allows to measure the field magnitude for the oscillating case.

System and method for assaying radiation

DOEpatents

DiPrete, David P; Whiteside, Tad; Pak, Donald J; DiPrete, Cecilia C

2013-11-12

A system for assaying radiation includes a sample holder configured to hold a liquid scintillation solution. A photomultiplier receives light from the liquid scintillation solution and generates a signal reflective of the light. A control circuit biases the photomultiplier and receives the signal from the photomultiplier reflective of the light. A light impermeable casing surrounds the sample holder, photomultiplier, and control circuit. A method for assaying radiation includes placing a sample in a liquid scintillation solution, placing the liquid scintillation solution in a sample holder, and placing the sample holder inside a light impermeable casing. The method further includes positioning a photomultiplier inside the light impermeable casing and supplying power to a control circuit inside the light impermeable casing.

Studies on a silicon-photomultiplier-based camera for Imaging Atmospheric Cherenkov Telescopes

NASA Astrophysics Data System (ADS)

Arcaro, C.; Corti, D.; De Angelis, A.; Doro, M.; Manea, C.; Mariotti, M.; Rando, R.; Reichardt, I.; Tescaro, D.

2017-12-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) represent a class of instruments which are dedicated to the ground-based observation of cosmic VHE gamma ray emission based on the detection of the Cherenkov radiation produced in the interaction of gamma rays with the Earth atmosphere. One of the key elements of such instruments is a pixelized focal-plane camera consisting of photodetectors. To date, photomultiplier tubes (PMTs) have been the common choice given their high photon detection efficiency (PDE) and fast time response. Recently, silicon photomultipliers (SiPMs) are emerging as an alternative. This rapidly evolving technology has strong potential to become superior to that based on PMTs in terms of PDE, which would further improve the sensitivity of IACTs, and see a price reduction per square millimeter of detector area. We are working to develop a SiPM-based module for the focal-plane cameras of the MAGIC telescopes to probe this technology for IACTs with large focal plane cameras of an area of few square meters. We will describe the solutions we are exploring in order to balance a competitive performance with a minimal impact on the overall MAGIC camera design using ray tracing simulations. We further present a comparative study of the overall light throughput based on Monte Carlo simulations and considering the properties of the major hardware elements of an IACT.

Liquid argon scintillation detection utilizing wavelength-shifting plates and light guides

NASA Astrophysics Data System (ADS)

Howard, B.

2018-02-01

In DUNE, the event timing provided by the detection of the relatively prompt scintillation photons will improve spatial resolution in the drift direction of the time-projection chamber (TPC) and is especially useful for non-beam physics topics such as supernova neutrinos and nucleon decay. The baseline design for the first 10kt single phase TPC fits the photon detector system in the natural gap between the wire planes of adjacent TPC volumes. A prototype photon detector design utilizes wavelength-shifter coated plates to convert the vacuum ultraviolet scintillation light to the optical and commercially-produced wavelength-shifting light guides to trap some of this light and transport it to an array of silicon photomultipliers at the end. This system and the testing performed to characterize the system and determine the efficiency are discussed.

Liquid Argon Scintillation Detection Utilizing Wavelength-Shifting Plates and Light Guides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard, B.

In DUNE, the event timing provided by the detection of the relatively prompt scintillation photons will improve spatial resolution in the drift direction of the time-projection chamber (TPC) and is especially useful for non-beam physics topics such as supernova neutrinos and nucleon decay. The baseline design for the first 10kt single phase TPC fits the photon detector system in the natural gap between the wire planes of adjacent TPC volumes. A prototype photon detector design utilizes wavelength-shifter coated plates to convert the vacuum ultraviolet scintillation light to the optical and commercially-produced wavelength-shifting light guides to trap some of this lightmore » and transport it to an array of silicon photomultipliers at the end. This system and the testing performed to characterize the system and determine the efficiency are discussed.« less

Development of a Modern Cosmic Ray Telescope based on Silicon Photomultipliers for use in High Schools

NASA Astrophysics Data System (ADS)

Ruiz Castruita, Daniel; Niduaza, Rommel; Hernandez, Victor; Knox, Adrian; Ramos, Daniel; Fan, Sewan; Fatuzzo, Laura

2015-04-01

Lately, a new light sensor technology based on the breakdown phenomenon in the reverse biased silicon diode has found many applications that span from particle physics to medical imaging science. The silicon photomultiplier (SiPM) has several notable advantages compared to conventional photomultiplier tubes which include: lower cost, lower operating voltage and the ability to measure very weak light signals at the single photon level. At this conference meeting, we describe our efforts to implement SiPMs as read out light detectors for plastic scintillators in a cosmic ray telescope for use in high schools. In particular, we describe our work in designing, testing and assembling the cosmic ray telescope. We include a high gain preamplifier, a custom coincidence circuit using fast comparators to discriminate the SiPM signal amplitudes and a monovibrator IC for lengthening the singles and coincidence logic pulses. An Arduino micro-controller and program sketches are used for processing and storing the singles and coincidence counts data. Results from our measurements would be illustrated and presented. US Department of Education Title V Grant Award PO31S090007.

Preventive maintenance system for the photomultiplier detector blocks of PET scanners

DOEpatents

Levy, A.V.; Warner, D.

1995-01-24

A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The qualitative comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t[sub 0], a time t[sub 1] and a time T, where T>t[sub 1]>t[sub 0], which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner. 40 figures.

Preventive maintenance system for the photomultiplier detector blocks of pet scanners

DOEpatents

Levy, Alejandro V.; Warner, Donald

1995-01-24

A system including a method and apparatus for preventive maintenance of PET scanner photomultiplier detector blocks is disclosed. The quantitive comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner. The system alerts the user to replace the defective photomultiplier block prior to catastrophic failure in a scheduled preventative maintenance program, thus eliminating expensive and unscheduled downtime of the PET scanner due to photomultiplier failure. The apparatus for carrying out the method of the present invention preferably resides in the host computer controlling a PET scanner. It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t.sub.0, a time t.sub.1 and a time T, where T>t.sub.1 >t.sub.0, which is designated as Histo(i,j(t)). The apparatus also includes a processor configured by a software program or a combination of programmed RAM and ROM devices to perform a number of calculations and operations on these values, and also includes a counter for analyzing each photomultiplier detector block i=1 through I of a PET scanner.

Preparatory Study of Photomultiplier Tubes of 10-inch and 3-inch Diameter for KM3NeT Underwater Neutrino Telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aiello, S.; Giordano, V.; Leonora, E.

Large area photomultipliers are widely used in neutrino and astro-particle detectors to measure Cherenkov light in media like water or ice. The key element of these detectors are the so-called 'optical module', which consists of a photodetector enclosed in a transparent pressure-resistant container to protect it and ensure good light transmission. KM3NeT collaboration aims to construct an underwater 'hybrid' neutrino telescope by using two models detection unit. The 'tower' detection unit will be composed of large area 10-inch photomultipliers tube enclosed into 13-inch glass vessel sphere. In the 'string' detection unit instead, the light detector will be the 'digital opticalmore » module' (DOM) a glass vessel of 17-inch with 31 photomultipliers of 3- inch diameter looking upwards and downwards. The choice of two different kinds of photomultipliers, obliges us to investigate their main characteristics. Noise pulses at the anode of each photomultiplier strongly affect the performance of the detector. A large study was conducted on noise pulses of large area photomultipliers, considering time and charge distributions of dark pulses, pre-pulses, delayed pulses, and after-pulses. The contribution to noise pulses due to the presence of the external glass vessels was also studied. Moreover the presence of the Earth's magnetic field should modify quantities like gain and transit time spread in photomultipliers and we will deeply investigate on this. (authors)« less

Liquid xenon calorimeter for MEG II experiment with VUV-sensitive MPPCs

NASA Astrophysics Data System (ADS)

Ogawa, Shinji; MEG II Collaboration

2017-02-01

The MEG II experiment is an upgrade of the MEG experiment to search for the charged lepton flavor violating decay of muon, μ+ →e+ γ . The MEG II experiment is expected to reach a branching ratio sensitivity of 4 ×10-14 , which is one order of magnitude better than the sensitivity of the current MEG experiment. The performance of the liquid xenon (LXe) γ-ray detector will be greatly improved with a highly granular scintillation readout realized by replacing 216 photomultiplier tubes (PMTs) on the γ-ray entrance face with 4092 Multi-Pixel Photon Counters (MPPCs). For this purpose, we have developed a new type of MPPC which is sensitive to the LXe scintillation light in vacuum ultraviolet (VUV) range, in collaboration with Hamamatsu Photonics K.K. We have measured the performance of the MPPC in LXe, and an excellent performance has been confirmed including high photon detection efficiency (> 15 %) for LXe scintillation light. An excellent performance of the LXe detector has been confirmed by Monte Carlo simulations based on the measured properties of the MPPC. The construction of the detector is in progress, aiming to start physics data taking in 2017.

Study of large hemispherical photomultiplier tubes for the ANTARES neutrino telescope

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Albert, A.; Ameli, F.; Amram, P.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardellier-Desages, F. E.; Aslanides, E.; Aubert, J.-J.; Bailey, D.; Basa, S.; Battaglieri, M.; Becherini, Y.; Bellotti, R.; Beltramelli, J.; Bertin, V.; Billault, M.; Blaes, R.; Blanc, F.; de Botton, N.; Boulesteix, J.; Bouwhuis, M. C.; Brooks, C. B.; Bradbury, S. M.; Bruijn, R.; Brunner, J.; Burgio, G. F.; Cafagna, F.; Calzas, A.; Capone, A.; Caponetto, L.; Carmona, E.; Carr, J.; Cartwright, S. L.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Charvis, P.; Circella, M.; Colnard, C.; Compère, C.; Coniglione, R.; Cooper, S.; Coyle, P.; Cuneo, S.; Damy, G.; van Dantzig, R.; Deschamps, A.; de Marzo, C.; Denans, D.; Destelle, J.-J.; de Vita, R.; Dinkelspiler, B.; Distefano, C.; Drogou, J.-F.; Druillole, F.; Engelen, J.; Ernenwein, J.-P.; Falchini, E.; Favard, S.; Feinstein, F.; Ferry, S.; Festy, D.; Flaminio, V.; Fopma, J.; Fuda, J.-L.; Gallone, J.-M.; Giacomelli, G.; Girard, N.; Goret, P.; Graf, K.; Hallewell, G.; Hartmann, B.; Heijboer, A.; Hello, Y.; Hernández-Rey, J. J.; Herrouin, G.; Hößl, J.; Hoffmann, C.; Hubbard, J. R.; Jaquet, M.; de Jong, M.; Jouvenot, F.; Kappes, A.; Karg, T.; Karkar, S.; Karolak, M.; Katz, U.; Keller, P.; Kooijman, P.; Korolkova, E. V.; Kouchner, A.; Kretschmer, W.; Kuch, S.; Kudryavtsev, V. A.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lamare, P.; Languillat, J.-C.; Laschinsky, H.; Laubier, L.; Legou, T.; Le Guen, Y.; Le Provost, H.; Le van Suu, A.; Lo Nigro, L.; Lo Presti, D.; Loucatos, S.; Louis, F.; Lyashuk, V.; Marcelin, M.; Margiotta, A.; Maron, C.; Massol, A.; Masullo, R.; Mazéas, F.; Mazure, A.; McMillan, J. E.; Migneco, E.; Millot, C.; Milovanovic, A.; Montanet, F.; Montaruli, T.; Morel, J.-P.; Morganti, M.; Moscoso, L.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Nezri, E.; Niess, V.; Nooren, G. J.; Ogden, P.; Olivetto, C.; Palanque-Delabrouille, N.; Papaleo, R.; Payre, P.; Petta, C.; Piattelli, P.; Pineau, J.-P.; Poinsignon, J.; Popa, V.; Potheau, R.; Pradier, T.; Racca, C.; Raia, G.; Randazzo, N.; Real, D.; van Rens, B. A. P.; Réthoré, F.; Riccobene, G.; Rigaud, V.; Ripani, M.; Roca-Blay, V.; Rolin, J.-F.; Romita, M.; Rose, H. J.; Rostovtsev, A.; Ruppi, M.; Russo, G. V.; Sacquin, Y.; Salesa, F.; Salomon, K.; Saouter, S.; Sapienza, P.; Shanidze, R.; Schuller, J.-P.; Schuster, W.; Sokalski, I.; Spurio, M.; Stolarczyk, T.; Stubert, D.; Taiuti, M.; Thompson, L. F.; Tilav, S.; Valdy, P.; Valente, V.; Vallage, B.; Vernin, P.; Virieux, J.; de Vries, G.; de Witt Huberts, P.; de Wolf, E.; Zaborov, D.; Zaccone, H.; Zakharov, V.; Zornoza, J. D.; Zúñiga, J.

2005-12-01

The ANTARES neutrino telescope, to be immersed depth in the Mediterranean Sea, will consist of a three-dimensional matrix of 900 large area photomultiplier tubes housed in pressure-resistant glass spheres. The selection of the optimal photomultiplier was a critical step for the project and required an intensive phase of tests and developments carried out in close collaboration with the main manufacturers worldwide. This paper provides an overview of the tests performed by the collaboration and describes in detail the features of the photomultiplier tube chosen for ANTARES.

Scintillation probe with photomultiplier tube saturation indicator

DOEpatents

Ruch, Jeffrey F.; Urban, David J.

1996-01-01

A photomultiplier tube saturation indicator is formed by supplying a supplemental light source, typically an light emitting diode (LED), adjacent to the photomultiplier tube. A switch allows the light source to be activated. The light is forwarded to the photomultiplier tube by an optical fiber. If the probe is properly light tight, then a meter attached to the indicator will register the light from the LED. If the probe is no longer light tight, and the saturation indicator is saturated, no signal will be registered when the LED is activated.

Evaluation of the amperex 56 TVP photomultiplier. [characteristics: photoelectron time spread, anode pulse amplitude and photocathode sensing area

NASA Technical Reports Server (NTRS)

Lo, C. C.; Leskovar, B.

1976-01-01

Characteristics were measured for the Amperex 56 TVP 42 mm-diameter photomultiplier. Some typical photomultiplier characteristics-such as gain, dark current, transit and rise times-are compared with data provided. Photomultiplier characteristics generally not available such as the single photoelectron time spread, the relative collection efficiency, the relative anode pulse amplitude as a function of the voltage between the photocathode and focusing electrode, and the position of the photocathode sensing area were measured and are discussed for two 56 TVP's. The single photoelectron time spread, the relative collection efficiency, and the transit time difference as a function of the voltage between photocathode and focusing electrode were also measured and are discussed, particularly with respect to the optimization of photomultiplier operating conditions for timing applications.

Characterization of 750 Large Area Photomultipliers for the KM3NeT-Italia towers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leonora, Emanuele; Aiello, S.; Giordano, V.

2015-07-01

The KM3NeT European experiment aims to construct a large volume underwater neutrino telescope, in the depths of the Mediterranean Sea. Thanks to a dedicated funding by the Italian Ministry of Education, University and Research, in its first phase named KM3NeT-Italia, an 8-towers detector is under construction, equipped with 672 optical sensors. The detection element of the telescope, the 'optical module', is composed by a 13-inch high-pressure glass-vessel that contains a single 10-inch photomultiplier. As the key sensor, all the characteristics of the photomultiplier have a severe impact on the performance of the whole detector. The selected photomultiplier was the 10-inchmore » R7081 PMT produced by Hamamatsu. In the frame of the optical modules mass production, performed in the INFN-LNS site of Catania, 750 photomultipliers have been tested by means of a dedicated test bench. The paper deals with the main results obtained from the massive photomultipliers measurements, which exhibited that such kind of devices comply with the general requirements imposed by the project. (authors)« less

Characterization of gigahertz (GHz) bandwidth photomultipliers

NASA Technical Reports Server (NTRS)

Abshire, J. B.; Rowe, H. E.

1977-01-01

The average impulse response, root-mean-square times jitter as a function of signal level, single photoelectron distribution, and multiphotoelectron dark-count distribution have been measured for two static crossed-field and five electrostatic photomultipliers. The optical signal source for the first three of these tests was a 30 picosecond mode-locked laser pulse at 0.53 micron. The static crossed-field detectors had 2-photoelectron resolution, less than 200 ps rise times, and rms time jitters of 30 ps at the single photoelectron level. The electrostatic photomultipliers had rise times from 1 to 2.5 nanoseconds, and rms time jitters from 160 to 650 ps at the same signal level. The two static crossed-field photomultipliers had ion-feedback-generated dark pulses to the 50-photoelectron level, whereas one electrostatic photomultiplier had dark pulses to the 30-photoelectron level.

Optical coupler

DOEpatents

Majewski, Stanislaw; Weisenberger, Andrew G.

2004-06-15

In a camera or similar radiation sensitive device comprising a pixilated scintillation layer, a light guide and an array of position sensitive photomultiplier tubes, wherein there exists so-called dead space between adjacent photomultiplier tubes the improvement comprising a two part light guide comprising a first planar light spreading layer or portion having a first surface that addresses the scintillation layer and optically coupled thereto at a second surface that addresses the photomultiplier tubes, a second layer or portion comprising an array of trapezoidal light collectors defining gaps that span said dead space and are individually optically coupled to individual position sensitive photomultiplier tubes. According to a preferred embodiment, coupling of the trapezoidal light collectors to the position sensitive photomultiplier tubes is accomplished using an optical grease having about the same refractive index as the material of construction of the two part light guide.

Study of the properties of new SPM detectors

NASA Astrophysics Data System (ADS)

Stewart, A. G.; Greene-O'Sullivan, E.; Herbert, D. J.; Saveliev, V.; Quinlan, F.; Wall, L.; Hughes, P. J.; Mathewson, A.; Jackson, J. C.

2006-02-01

The operation and performance of multi-pixel, Geiger-mode APD structures referred to as Silicon Photomultiplier (SPM) are reported. The SPM is a solid state device that has emerged over the last decade as a promising alternative to vacuum PMTs. This is due to their comparable performance in addition to their lower bias operation and power consumption, insensitivity to magnetic fields and ambient light, smaller size and ruggedness. Applications for these detectors are numerous and include life sciences, nuclear medicine, particle physics, microscopy and general instrumentation. With SPM devices, many geometrical and device parameters can be adjusted to optimize their performance for a particular application. In this paper, Monte Carlo simulations and experimental results for 1mm2 SPM structures are reported. In addition, trade-offs involved in optimizing the SPM in terms of the number and size of pixels for a given light intensity, and its affect on the dynamic range are discussed.

Light yield of Kuraray SCSF-78MJ scintillating fibers for the Gluex barrel calorimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beattie, T D; Fischer, A P; Krueger, S T

Over three quarters of a million 1-mm-diameter 4-m-long Kuraray double-clad SCSF-78MJ (blue-green) scintillating fibers have been used in the construction of the GlueX electromagnetic barrel calorimeter for the Hall D experimental program at Jefferson Lab. The quality of a random sample of 4,750 of these fibers was evaluated by exciting the fibers at their mid point using a 90Sr source in order to determine the light yield using a calibrated vacuum photomultiplier as the photosensor. A novel methodology was developed to extract the number of photoelectrons detected for measurements where individual photoelectron peaks are not discernible. The average number ofmore » photoelectrons from this sample of fibers was 9.17±0.6 at a source distance of 200 cm from the PMT.« less

Development of visible spectroscopy diagnostics for W sources assessment in WEST

NASA Astrophysics Data System (ADS)

Meyer, O.; Jones, O. M.; Giacalone, J. C.; Pascal, J. Y.; Raulin, D.; Xu, H.; Aumeunier, M. H.; Baude, R.; Escarguel, A.; Gil, C.; Harris, J. H.; Hatchressian, J.-C.; Klepper, C. C.; Larroque, S.; Lotte, Ph.; Moreau, Ph.; Pégourié, B.; Vartanian, S.

2016-11-01

The present work concerns the development of a W sources assessment system in the framework of the tungsten-W environment in steady state tokamak project that aims at equipping the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFCs) in view of preparing ITER operation. The goal is to assess W sources and D recycling with spectral, spatial, and temporal resolution adapted to the PFCs observed. The originality of the system is that all optical elements are installed in the vacuum vessel and compatible with steady state operation. Our system is optimized to measure radiance as low as 1016 Ph/(m2 s sr). A total of 240 optical fibers will be deployed to the detection systems such as the "Filterscope," developed by Oak Ridge National Laboratory (USA) and consisting of photomultiplier tubes and filters, or imaging spectrometers dedicated to Multiview analysis.

Signal-Induced Noise Effects in a Photon Counting System for Stratospheric Ozone Measurement

NASA Technical Reports Server (NTRS)

Harper, David B.; DeYoung, Russell J.

1998-01-01

A significant source of error in making atmospheric differential absorption lidar ozone measurements is the saturation of the photomultiplier tube by the strong, near field light return. Some time after the near field light signal is gone, the photomultiplier tube gate is opened and a noise signal, called signal-induced noise, is observed. Research reported here gives experimental results from measurement of photomultiplier signal-induced noise. Results show that signal-induced noise has several decaying exponential signals, suggesting that electrons are slowly emitted from different surfaces internal to the photomultiplier tube.

Time-domain diffuse optical tomography using silicon photomultipliers: feasibility study.

PubMed

Di Sieno, Laura; Zouaoui, Judy; Hervé, Lionel; Pifferi, Antonio; Farina, Andrea; Martinenghi, Edoardo; Derouard, Jacques; Dinten, Jean-Marc; Mora, Alberto Dalla

2016-11-01

Silicon photomultipliers (SiPMs) have been very recently introduced as the most promising detectors in the field of diffuse optics, in particular due to the inherent low cost and large active area. We also demonstrate the suitability of SiPMs for time-domain diffuse optical tomography (DOT). The study is based on both simulations and experimental measurements. Results clearly show excellent performances in terms of spatial localization of an absorbing perturbation, thus opening the way to the use of SiPMs for DOT, with the possibility to conceive a new generation of low-cost and reliable multichannel tomographic systems.

The new versatile general purpose surface-muon instrument (GPS) based on silicon photomultipliers for μSR measurements on a continuous-wave beam

NASA Astrophysics Data System (ADS)

Amato, A.; Luetkens, H.; Sedlak, K.; Stoykov, A.; Scheuermann, R.; Elender, M.; Raselli, A.; Graf, D.

2017-09-01

We report on the design and commissioning of a new spectrometer for muon-spin relaxation/rotation studies installed at the Swiss Muon Source (SμS) of the Paul Scherrer Institute (PSI, Switzerland). This new instrument is essentially a new design and replaces the old general-purpose surface-muon (GPS) instrument that has been for long the workhorse of the μSR user facility at PSI. By making use of muon and positron detectors made of plastic scintillators read out by silicon photomultipliers, a time resolution of the complete instrument of about 160 ps (standard deviation) could be achieved. In addition, the absence of light guides, which are needed in traditionally built μSR instrument to deliver the scintillation light to photomultiplier tubes located outside magnetic fields applied, allowed us to design a compact instrument with a detector set covering an increased solid angle compared with the old GPS.

Studying Silicon Photomultipliers and Light Signal Acquisition for the SBND Experiment

NASA Astrophysics Data System (ADS)

Savard, Claire; SBND Collaboration

2017-01-01

The Short-Baseline Near Detector (SBND) is one of three Liquid Argon Time Projection Chamber (LArTPC) based detectors that will be used in the Short-Baseline Neutrino (SBN) program at Fermilab. SBN will study the neutrino-argon interaction and search for oscillations at short baseline. Light produced in neutrino interactions inside a LArTPC provides a precision measurement of the initial interaction time of the event, essential for differentiating non-beam-background from beam-based signal. I will discuss the light guide system for SBND, with an emphasis on the Silicon Photomultiplier (SiPM) readout and data acquisition. In particular, I will show results from testing and characterizing a candidate electronics board for reading out the SiPM signals.

Study on 3-inch Hamamatsu photomultipliers

NASA Astrophysics Data System (ADS)

Giordano, Valentina; Aiello, Sebastiano; Leonora, Emanuele

2016-07-01

Several kinds of photomultipliers are widely used in astroparticle physics detectors to measure Cherenkov light in media like water or ice. In neutrino telescopes the key element of the detector is the optical module, which consists of one or more photodetectors inside a transparent pressure-resistant glass sphere. It serves as mechanical protection while ensuring good light transmission. The KM3NeT collaboration has developed an innovative design of an optical module composed by 31 photomultipliers (PMTs) of 3-inch diameter housed in a 17-inch glass shpere. The performance of the telescope is largely dependent on the presence on noise pulses present on the anode of the photomultipliers. A study was conducted of noise pulses of Hamamatsu 3-inch diameter photomultipliers measuring time and charge distributions of dark pulses, pre-pulses, delayed pulses and after-pulses, focusing in particular on analysis on multiple afterpulses. Effects of the Earth's magnetic field on 3-inch PMTs were also studied.

Fabrication, characterization and testing of silicon photomultipliers for the Muon Portal Project

NASA Astrophysics Data System (ADS)

La Rocca, P.; Billotta, S.; Blancato, A. A.; Bonanno, D.; Bonanno, G.; Fallica, G.; Garozzo, S.; Lo Presti, D.; Marano, D.; Pugliatti, C.; Riggi, F.; Romeo, G.; Santagati, G.; Valvo, G.

2015-07-01

The Muon Portal is a recently started Project aiming at the construction of a large area tracking detector that exploits the muon tomography technique to inspect the contents of traveling cargo containers. The detection planes will be made of plastic scintillator strips with embedded wavelength-shifting fibres. Special designed silicon photomultipliers will read the scintillation light transported by the fibres along the strips and a dedicated electronics will combine signals from different strips to reduce the overall number of channels, without loss of information. Different silicon photomultiplier prototypes, both with the p-on-n and n-on-p technologies, have been produced by STMicroelectronics during the last years. In this paper we present the main characteristics of the silicon photomultipliers designed for the Muon Portal Project and describe the setup and the procedure implemented for the characterization of these devices, giving some statistical results obtained from the test of a first batch of silicon photomultipliers.

A system for measuring the pulse height distribution of ultrafast photomultipliers

NASA Technical Reports Server (NTRS)

Abshire, J. B.

1977-01-01

A system for measuring the pulse height distribution of gigahertz bandwidth photomultipliers was developed. This system uses a sampling oscilloscope as a sample-hold circuit and has a bandwidth of 12 gigahertz. Test results are given for a static crossed-filed photomultiplier tested with a demonstration system. Calculations on system amplitude resolution capabilities are included for currently available system components.

Semiconductor superlattice photodetectors

NASA Technical Reports Server (NTRS)

Chuang, S. L.; Hess, K.; Coleman, J. J.; Leburton, J. P.

1985-01-01

Two novel types of superlattice photodetectors were studied. The first was a superlattice photomultiplier and the second a photodetector based on the real space transfer mechanism. A summary of the results is presented.

Development of a thin scintillation films fission-fragment detector and a novel neutron source

NASA Astrophysics Data System (ADS)

Rusev, G.; Jandel, M.; Baramsai, B.; Bond, E. M.; Bredeweg, T. A.; Couture, A.; Daum, J. K.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Roman, A. R.; Springs, R. K.; Ullmann, J. L.; Walker, C. L.

2015-08-01

Investigation of prompt fission and neutron-capture Υ rays from fissile actinide samples at the Detector for Advanced Neutron Capture Experiments (DANCE) requires use of a fission-fragment detector to provide a trigger or a veto signal. A fission-fragment detector based on thin scintillating films and silicon photomultipliers has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing a 4π detection of the fission fragments. The scintillations were registered with silicon photomultipliers. A measurement of the 235U(n,f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described. A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of 252Cf and the same type of scintillating films and silicon photomultipliers. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements with it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.

Study of solid state photomultiplier

NASA Technical Reports Server (NTRS)

Hays, K. M.; Laviolette, R. A.

1987-01-01

Available solid state photomultiplier (SSPM) detectors were tested under low-background, low temperature conditions to determine the conditions producing optimal sensitivity in a space-based astronomy system such as a liquid cooled helium telescope in orbit. Detector temperatures varied between 6 and 9 K, with background flux ranging from 10 to the 13th power to less than 10 to the 6th power photons/square cm-s. Measured parameters included quantum efficiency, noise, dark current, and spectral response. Experimental data were reduced, analyzed, and combined with existing data to build the SSPM data base included herein. The results were compared to analytical models of SSPM performance where appropriate models existed. Analytical models presented here were developed to be as consistent with the data base as practicable. Significant differences between the theory and data are described. Some models were developed or updated as a result of this study.

Analysis of small droplets with a new detector for liquid chromatography based on laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Janzen, Christoph; Fleige, Rüdiger; Noll, Reinhard; Schwenke, Heinrich; Lahmann, Wilhelm; Knoth, Joachim; Beaven, Peter; Jantzen, Eckard; Oest, Andreas; Koke, Peter

2005-08-01

The miniaturization of analytical techniques is a general trend in speciation analytics. We have developed a new analytical technique combining high pressure liquid chromatography (HPLC) with laser-induced breakdown spectroscopy (LIBS). This enables a molecule-specific separation followed by an element-specific analysis of smallest amounts of complex samples. The liquid flow coming from a HPLC pump is transformed into a continuous stream of small droplets (diameter 50-100 μm, volume 65-500 pl) using a piezoelectric pulsed nozzle. After the detection of single droplets with a droplet detector, a Q-switched Nd:YAG Laser is triggered to emit a synchronized laser pulse that irradiates a single droplet. The droplets are evaporated and transformed to the plasma state. The spectrum emitted from the plasma is collected by a spherical mirror and directed through the entrance slit of a Paschen-Runge spectrometer equipped with channel photomultipliers. The spectrometer detects 31 elements simultaneously covering a spectral range from 120 to 589 nm. Purging the measurement chamber with argon enables the detection of vacuum-UV lines. Since the sample is transferred to the plasma state without dilution, very low flow rates in the sub-μl/min range can be realised.

A collimated neutron detector for RFP plasmas in MST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capecchi, W. J., E-mail: capecchi@wisc.edu; Anderson, J. K.; Bonofiglo, P. J.

The neutron emissivity profile in the Madison Symmetric Torus is being reconstructed through the use of a collimated neutron detector. A scintillator-photomultiplier tube (PMT) system is employed to detect the fusion neutrons with the plasma viewing volume defined by a 55 cm deep, 5 cm diameter aperture. Effective detection of neutrons from the viewing volume is achieved through neutron moderation using 1300 lbs of high density polyethylene shielding, which modeling predicts attenuates the penetrating flux by a factor of 10{sup 4} or more. A broad spectrum of gamma radiation is also present due to the unconfined fusion proton bombardment ofmore » the thick aluminum vacuum vessel. A 15 cm cylindrical liquid scintillator of 3.8 cm diameter is used to further increase directional sensitivity. A fast (5 ns rise time) preamplifier and digitization at 500 MHz prevent pulse pile-up even at high count rates (∼10{sup 4}/s). The entire neutron camera system is situated on an adjustable inclining base which provides the differing plasma viewing volumes necessary for reconstruction of the neutron emissivity profile. This profile, directly related to the fast-ion population, allows for an investigation of the critical fast-ion pressure gradient required to destabilize a neutral beam driven Alfvénic mode which has been shown to transport fast ions.« less

Calibration of photo sensors for the space-based cosmic ray telescope JEM-EUSO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karus, Michael

2015-02-24

In order to unveil the mystery of ultra-high energy cosmic rays (UHECRs), the planned fluorescence telescope JEM-EUSO (Extreme Universe Space Observatory on-board Japanese Experiment Module) will observe extensive air showers induced by UHECRs from the International Space Station (ISS) orbit with a huge acceptance. The JEM-EUSO instrument consists of Fresnel optics and a focal surface detector with 5000 multi-anode photomultiplier tubes (MAPMTs), 300000 channels in total. For fluorescence detection of cosmic rays it is essential to calibrate the detector pre-flight with utmost precision and to monitor the performance of the detector throughout the whole mission time. For that purpose amore » calibration stand on-ground was built to measure precisely the performance of Hamamatsu 64 pixel MAPMTs that are planned to be used for JEM-EUSO. To investigate the suitability of alternative detector devices, further research is done with state-of-the-art silicon photomultipliers (SiPMs), namely Hamamatsu multi-pixel photon counters (MPPCs). These will also be tested in the calibration stand and their performance can be compared to conventional photomultiplier tubes.« less

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Otte, A. N.; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Horan, D.; Mukherjee, R.; Smith, A.; Tajima, H.; Wagner, R. G.; Williams, D. A.

2008-12-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. Design goals are ten times better sensitivity, higher angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel diameter is reduced to the order of 0.05 deg, i.e. two to three times smaller than the pixel diameter of current Cherenkov telescope cameras. At these dimensions, photon detectors with smaller physical dimensions can be attractive alternatives to the classical photomultiplier tube (PMT). Furthermore, the operation of an experiment with the size of AGIS requires photon detectors that are among other things more reliable, more durable, and possibly higher efficiency photon detectors. Alternative photon detectors we are considering for AGIS include both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs). Here we present results from laboratory testing of MAPMTs and SiPMs along with results from the first incorporation of these devices into cameras on test bed Cherenkov telescopes.

Photomultiplier tube gain regulating system

DOEpatents

Johnson, Wayne F.

1976-01-01

This invention relates to an improved system for regulating the gain of a photomultiplier tube, and was designed for use with the photomultiplier tubes of a GeMSAEC fast analyzers. It has the following advantages over the prior system: noise is virtually eliminated; sample analysis can begin after 3 to 4 revolutions of the rotor; fluorescent and light scattering solutions can be used as a reference; and the reference solution can be in any cuvette on the rotor.

Application of CMOS Technology to Silicon Photomultiplier Sensors.

PubMed

D'Ascenzo, Nicola; Zhang, Xi; Xie, Qingguo

2017-09-25

We use the 180 nm GLOBALFOUNDRIES (GF) BCDLite CMOS process for the production of a silicon photomultiplier prototype. We study the main characteristics of the developed sensor in comparison with commercial SiPMs obtained in custom technologies and other SiPMs developed with CMOS-compatible processes. We support our discussion with a transient modeling of the detection process of the silicon photomultiplier as well as with a series of static and dynamic experimental measurements in dark and illuminated environments.

Characterisation of the Hamamatsu photomultipliers for the KM3NeT Neutrino Telescope

NASA Astrophysics Data System (ADS)

Aiello, S.; Akrame, S. E.; Ameli, F.; Anassontzis, E. G.; Andre, M.; Androulakis, G.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aublin, J.; Avgitas, T.; Baars, M.; Bagatelas, C.; Barbarino, G.; Baret, B.; Barrios-Martí, J.; Belias, A.; Berbee, E.; van den Berg, A.; Bertin, V.; Biagi, S.; Biagioni, A.; Biernoth, C.; Bormuth, R.; Boumaaza, J.; Bourret, S.; Bouwhuis, M.; Bozza, C.; Brânzaş, H.; Briukhanova, N.; Bruijn, R.; Brunner, J.; Buis, E.; Buompane, R.; Busto, J.; Calvo, D.; Capone, A.; Caramete, L.; Celli, S.; Chabab, M.; Cherubini, S.; Chiarella, V.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coelho, J. A. B.; Coleiro, A.; Colomer Molla, M.; Coniglione, R.; Coyle, P.; Creusot, A.; Cuttone, G.; D'Onofrio, A.; Dallier, R.; De Sio, C.; Di Palma, I.; Díaz, A. F.; Distefano, C.; Domi, A.; Donà, R.; Donzaud, C.; Dornic, D.; Dörr, M.; Durocher, M.; Eberl, T.; van Eijk, D.; El Bojaddaini, I.; Elsaesser, D.; Enzenhöfer, A.; Ferrara, G.; Fusco, L. A.; Gal, T.; Garufi, F.; Gauchery, S.; Geißelsöder, S.; Gialanella, L.; Giorgio, E.; Giuliante, A.; Gozzini, S. R.; Ruiz, R. Gracia; Graf, K.; Grasso, D.; Grégoire, T.; Grella, G.; Hallmann, S.; van Haren, H.; Heid, T.; Heijboer, A.; Hekalo, A.; Hernández-Rey, J. J.; Hofestädt, J.; Illuminati, G.; James, C. W.; Jongen, M.; Jongewaard, B.; de Jong, M.; de Jong, P.; Kadler, M.; Kalaczyński, P.; Kalekin, O.; Katz, U. F.; Chowdhury, N. R. Khan; Kieft, G.; Kießling, D.; Koffeman, E. N.; Kooijman, P.; Kouchner, A.; Kreter, M.; Kulikovskiy, V.; Lahmann, R.; Le Breton, R.; Leone, F.; Leonora, E.; Levi, G.; Lincetto, M.; Lonardo, A.; Longhitano, F.; Lotze, M.; Loucatos, S.; Maggi, G.; Mańczak, J.; Mannheim, K.; Margiotta, A.; Marinelli, A.; Markou, C.; Martin, L.; Martínez-Mora, J. A.; Martini, A.; Marzaioli, F.; Mele, R.; Melis, K. W.; Migliozzi, P.; Migneco, E.; Mijakowski, P.; Miranda, L. S.; Mollo, C. M.; Morganti, M.; Moser, M.; Moussa, A.; Muller, R.; Musumeci, M.; Nauta, L.; Navas, S.; Nicolau, C. A.; Nielsen, C.; Organokov, M.; Orlando, A.; Panagopoulos, V.; Papalashvili, G.; Papaleo, R.; Păvălaş, G. E.; Pellegrini, G.; Pellegrino, C.; Pérez Romero, J.; Perrin-Terrin, M.; Piattelli, P.; Pikounis, K.; Pisanti, O.; Poirè, C.; Polydefki, G.; Poma, G. E.; Popa, V.; Post, M.; Pradier, T.; Pühlhofer, G.; Pulvirenti, S.; Quinn, L.; Raffaelli, F.; Randazzo, N.; Razzaque, S.; Real, D.; Resvanis, L.; Reubelt, J.; Riccobene, G.; Richer, M.; Rovelli, A.; Salvadori, I.; Samtleben, D. F. E.; Sánchez Losa, A.; Sanguineti, M.; Santangelo, A.; Sapienza, P.; Schermer, B.; Sciacca, V.; Seneca, J.; Sgura, I.; Shanidze, R.; Sharma, A.; Simeone, F.; Sinopoulou, A.; Spisso, B.; Spurio, M.; Stavropoulos, D.; Steijger, J.; Stellacci, S. M.; Strandberg, B.; Stransky, D.; Stüven, T.; Taiuti, M.; Tatone, F.; Tayalati, Y.; Tenllado, E.; Thakore, T.; Timmer, P.; Trovato, A.; Tsagkli, S.; Tzamariudaki, E.; Tzanetatos, D.; Valieri, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Viola, S.; Vivolo, D.; Volkert, M.; de Waardt, L.; Wilms, J.; de Wolf, E.; Zaborov, D.; Zornoza, J. D.; Zúñiga, J.

2018-05-01

The Hamamatsu R12199-02 3-inch photomultiplier tube is the photodetector chosen for the first phase of the KM3NeT neutrino telescope. About 7000 photomultipliers have been characterised for dark count rate, timing spread and spurious pulses. The quantum efficiency, the gain and the peak-to-valley ratio have also been measured for a sub-sample in order to determine parameter values needed as input to numerical simulations of the detector.

Model independent approach to the single photoelectron calibration of photomultiplier tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saldanha, R.; Grandi, L.; Guardincerri, Y.

2017-08-01

The accurate calibration of photomultiplier tubes is critical in a wide variety of applications in which it is necessary to know the absolute number of detected photons or precisely determine the resolution of the signal. Conventional calibration methods rely on fitting the photomultiplier response to a low intensity light source with analytical approximations to the single photoelectron distribution, often leading to biased estimates due to the inability to accurately model the full distribution, especially at low charge values. In this paper we present a simple statistical method to extract the relevant single photoelectron calibration parameters without making any assumptions aboutmore » the underlying single photoelectron distribution. We illustrate the use of this method through the calibration of a Hamamatsu R11410 photomultiplier tube and study the accuracy and precision of the method using Monte Carlo simulations. The method is found to have significantly reduced bias compared to conventional methods and works under a wide range of light intensities, making it suitable for simultaneously calibrating large arrays of photomultiplier tubes.« less

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

NASA Astrophysics Data System (ADS)

Pate, S. F.; Wester, T.; Bugel, L.; Conrad, J.; Henderson, E.; Jones, B. J. P.; McLean, A. I. L.; Moon, J. S.; Toups, M.; Wongjirad, T.

2018-02-01

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (NPE) given the known systematic errors on the simulation parameters. We compare results from four measurements of the NPE determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of 0.0055±0.0009 for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.

Sample positioning apparatus

DOEpatents

Bell, Thomas H.; Johnson, Jr., Charles H.; Lane, Robert L.; Martin, Bradley E.; Tyree, William H.

1976-01-06

Apparatus for use in alpha particle counting with such as photomultiplier tubes, comprising a platform and linkage mechanism whereby samples are moved in linear manner toward and away from ends of the photomultiplier tubes.

Performance of photomultiplier tubes and sodium iodide scintillation detector systems

NASA Technical Reports Server (NTRS)

Meegan, C. A.

1981-01-01

The performance of photomultiplier tubes (PMT's) and scintillation detector systems incorporating 50.8 by 1.27 cm NaI (T l) crystals was investigated to determine the characteristics of the photomultiplier tubes and optimize the detector geometry for the Burst and Transient Source Experiment on the Gamma Ray Observatory. Background information on performance characteristics of PMT's and NaI (T l) detectors is provided, procedures for measurement of relevant parameters are specified, and results of these measurements are presented.

Application of CMOS Technology to Silicon Photomultiplier Sensors

PubMed Central

D’Ascenzo, Nicola; Zhang, Xi; Xie, Qingguo

2017-01-01

We use the 180 nm GLOBALFOUNDRIES (GF) BCDLite CMOS process for the production of a silicon photomultiplier prototype. We study the main characteristics of the developed sensor in comparison with commercial SiPMs obtained in custom technologies and other SiPMs developed with CMOS-compatible processes. We support our discussion with a transient modeling of the detection process of the silicon photomultiplier as well as with a series of static and dynamic experimental measurements in dark and illuminated environments. PMID:28946675

Study the performance of LYSO and CeBr3 crystals using Silicon Photomultipliers

NASA Astrophysics Data System (ADS)

Kryemadhi, Abaz

2016-03-01

The Silicon Photomultipliers (SiPMs) are novel photon-detectors which have been progressively found their use in particle physics. Their small size, good single photon resolution, simple readout, and immunity to magnetic fields offers advantages compared to traditional photomultipliers. LYSO and CeBr3 crystals are relatively new scintillators with high light yield and fast decay time. The response of these detectors to low energy gamma rays and cosmic ray muons will be presented. Messiah College Workload Reallocation Program.

Development of a thin scintillation films fission-fragment detector and a novel neutron source

DOE PAGES

Rusev, Gencho Yordanov; Jandel, Marian; Baramsai, Bayarbadrakh; ...

2015-08-26

Here, investigation of prompt fission and neutron-capture Υ rays from fissile actinide samples at the Detector for Advanced Neutron Capture Experiments (DANCE) requires use of a fission-fragment detector to provide a trigger or a veto signal. A fission-fragment detector based on thin scintillating films and silicon photomultipliers has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing a 4π detection of the fission fragments. The scintillations were registered with silicon photomultipliers. A measurement of the 235U(n,f) reaction with this detector at DANCE revealed a correct time-of-flightmore » spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described. A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of 252Cf and the same type of scintillating films and silicon photomultipliers. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements with it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.« less

Development of visible spectroscopy diagnostics for W sources assessment in WEST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, O., E-mail: olivier.meyer@cea.fr; Giacalone, J. C.; Pascal, J. Y.

2016-11-15

The present work concerns the development of a W sources assessment system in the framework of the tungsten-W environment in steady state tokamak project that aims at equipping the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFCs) in view of preparing ITER operation. The goal is to assess W sources and D recycling with spectral, spatial, and temporal resolution adapted to the PFCs observed. The originality of the system is that all optical elements are installed in the vacuum vessel and compatible with steady state operation. Our system ismore » optimized to measure radiance as low as 10{sup 16} Ph/(m{sup 2} s sr). A total of 240 optical fibers will be deployed to the detection systems such as the “Filterscope,” developed by Oak Ridge National Laboratory (USA) and consisting of photomultiplier tubes and filters, or imaging spectrometers dedicated to Multiview analysis.« less

Neutron camera employing row and column summations

DOEpatents

Clonts, Lloyd G.; Diawara, Yacouba; Donahue, Jr, Cornelius; Montcalm, Christopher A.; Riedel, Richard A.; Visscher, Theodore

2016-06-14

For each photomultiplier tube in an Anger camera, an R.times.S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P.times.Q array of photomultiplier tubes, P.times.Q summation circuitries generate P.times.Q row histograms including R entries and P.times.Q column histograms including S entries. The total set of histograms include P.times.Q.times.(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).

NectarCAM, a camera for the medium sized telescopes of the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Glicenstein, J.-F.; Shayduk, M.

2017-01-01

NectarCAM is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) which covers the core energy range of 100 GeV to 30 TeV. It has a modular design and is based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 8 degrees. Each module includes photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and Ethernet transceiver. The recorded events last between a few nanoseconds and tens of nanoseconds. The expected performance of the camera are discussed. Prototypes of NectarCAM components have been built to validate the design. Preliminary results of a 19-module mini-camera are presented, as well as future plans for building and testing a full size camera.

High-efficiency scintillation detector for combined detection of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, M.M.; Mihalczo, J.T.; Blakeman, E.D.

1987-02-27

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation event count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-02-07

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation

DOEpatents

Chiles, Marion M.; Mihalczo, John T.; Blakeman, Edward D.

1989-01-01

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

Reduction of space charge effects and tests of larger samples of photomultipliers for the EDDA experiment

NASA Astrophysics Data System (ADS)

Ackerstaff, K.; Bisplinghoff, J.; Bollmann, R.; Cloth, P.; Dohrmann, F.; Diehl, O.; Dorner, G.; Drüke, V.; Engelhardt, H. J.; Eisenhardt, S.; Ernst, J.; Eversheim, P. D.; Filges, D.; Fritz, S.; Gasthuber, M.; Gebel, R.; Gross, A.; Gross-Hardt, R.; Hinterberger, F.; Jahn, R.; Lahr, U.; Langkau, R.; Lippert, G.; Mayer-Kuckuk, T.; Maschuw, R.; Mertler, G.; Metsch, B.; Mosel, F.; Paetz gen. Schieck, H.; Petry, H. R.; Prasuhn, D.; v. Przewoski, B.; Radtke, M.; Rohdjess, H.; Rosendaal, D.; von Rossen, P.; Scheid, H.; Schirm, N.; Schwandt, F.; Scobel, W.; Theis, D.; Weber, J.; Wiedmann, W.; Woller, K.; Ziegler, R.; EDDA Collaboration

1993-10-01

For the EDDA experiment at COSY, the response of the small, linear focused photomultipliers Hamamatsu R 1450 and R 1355 has been studied with fast light pulses generating yields up to 2 × 10 3 photoelectrons/cm 2 or peak currents of 24 mA. Linearity was obtained with a tapered bleeder chain at a tolerable loss of gain. The serial test of altogether 140 photomultipliers revealed the close correlation between single electron and amplitude resolution. The influence of the photoelectron statistics on this correlation is discussed.

A large surface photomultiplier based on SiPMs

NASA Astrophysics Data System (ADS)

Barbarino, Giancarlo; de Asmundis, Riccardo; De Rosa, Gianfranca; Vivolo, Daniele; Mollo, Carlos Maximiliano

2013-10-01

Light detection through photosensitive devices represents one of the key issues for a large variety of experiments. In the recent years, Silicon PhotoMultipliers (SiPMs) based on limited Geiger-mode avalanche have been extensively studied in view of their future applications. However, their use is strongly limited by their small sensitive surfaces and by the fact that any increment in the surface turns out into an increase of the dark count rate. In the present work we describe the dark count rate reduction obtained by using a FPGA-based logical circuit for fast pre-processing of pulses from a 3×3 matrix of SiPMs. The prototype we developed supports two SiPMs: we show that a rate reduction from 6.6 Mcps (Mega counts per second) down to 0.436 Mcps at the lowest threshold (0.5 photon-equivalent) and from 1.2 kcps down to 0.02 cps for the highest threshold (3.5 photon-equivalent) is obtainable.

Compact, high-resolution, gamma ray imaging for scintimammography and other medical diagostic applications

DOEpatents

Majewski, Stanislaw; Weisenberger, Andrew G.; Wojcik, Randolph F.; Steinbach, Daniela

1999-01-01

A high resolution gamma ray imaging device includes an aluminum housing, a lead screen collimator at an opened end of the housing, a crystal scintillator array mounted behind the lead screen collimator, a foam layer between the lead screen collimator and the crystal scintillator array, a photomultiplier window coupled to the crystal with optical coupling grease, a photomultiplier having a dynode chain body and a base voltage divider with anodes, anode wire amplifiers each connected to four anodes and a multi pin connector having pin connections to each anode wire amplifier. In one embodiment the crystal scintillator array includes a yttrium aluminum perovskite (YAP) crystal array. In an alternate embodiment, the crystal scintillator array includes a gadolinium oxyorthosilicate (GSO) crystal array.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, R. G.; Byrum, K.; Drake, G.; Funk, S.; Otte, N.; Smith, A.; Tajima, H.; Williams, D.

2009-05-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. It is being designed to achieve a significant improvement in sensitivity compared to current Imaging Air Cherenkov Telescope (IACT) Arrays. One of the main requirements in order that AGIS fulfills this goal will be to achieve higher angular resolution than current IACTs. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to 0.05 deg, i.e. two to three times smaller than for current IACT cameras. Here we present results from testing of alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs).

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

DOE PAGES

Pate, S. F.; Wester, T.; Bugel, L.; ...

2018-02-28

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (more » $$N_{\\rm PE}$$) given the known systematic errors on the simulation parameters. We compare results from four measurements of the $$N_{\\rm PE}$$ determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of $$0.0055\\pm0.0009$$ for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.« less

A model for the Global Quantum Efficiency for a TPB-based wavelength-shifting system used with photomultiplier tubes in liquid argon in MicroBooNE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pate, S. F.; Wester, T.; Bugel, L.

We present a model for the Global Quantum Efficiency (GQE) of the MicroBooNE optical units. An optical unit consists of a flat, circular acrylic plate, coated with tetraphenyl butadiene (TPB), positioned near the photocathode of a 20.2-cm diameter photomultiplier tube. The plate converts the ultra-violet scintillation photons from liquid argon into visible-spectrum photons to which the cryogenic phototubes are sensitive. The GQE is the convolution of the efficiency of the plates that convert the 128 nm scintillation light from liquid argon to visible light, the efficiency of the shifted light to reach the photocathode, and the efficiency of the cryogenic photomultiplier tube. We develop a GEANT4-based model of the optical unit, based on first principles, and obtain the range of probable values for the expected number of detected photoelectrons (more » $$N_{\\rm PE}$$) given the known systematic errors on the simulation parameters. We compare results from four measurements of the $$N_{\\rm PE}$$ determined using alpha-particle sources placed at two distances from a TPB-coated plate in a liquid argon cryostat test stand. We also directly measured the radial dependence of the quantum efficiency, and find that this has the same shape as predicted by our model. Our model results in a GQE of $$0.0055\\pm0.0009$$ for the MicroBooNE optical units. While the information shown here is MicroBooNE specific, the approach to the model and the collection of simulation parameters will be widely applicable to many liquid-argon-based light collection systems.« less

A restraint-free small animal SPECT imaging system with motion tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisenberger, A.G.; Gleason, S.S.; Goddard, J.

2005-06-01

We report on an approach toward the development of a high-resolution single photon emission computed tomography (SPECT) system to image the biodistribution of radiolabeled tracers such as Tc-99m and I-125 in unrestrained/unanesthetized mice. An infrared (IR)-based position tracking apparatus has been developed and integrated into a SPECT gantry. The tracking system is designed to measure the spatial position of a mouse's head at a rate of 10-15 frames per second with submillimeter accuracy. The high-resolution, gamma imaging detectors are based on pixellated NaI(Tl) crystal scintillator arrays, position-sensitive photomultiplier tubes, and novel readout circuitry requiring fewer analog-digital converter (ADC) channels whilemore » retaining high spatial resolution. Two SPECT gamma camera detector heads based upon position-sensitive photomultiplier tubes have been built and installed onto the gantry. The IR landmark-based pose measurement and tracking system is under development to provide animal position data during a SPECT scan. The animal position and orientation data acquired by the tracking system will be used for motion correction during the tomographic image reconstruction.« less

γ{\\hbox-}Flash suppression using a gated photomultiplier assembled with an LaBr3(Ce) detector to measure fast neutron capture reactions

NASA Astrophysics Data System (ADS)

Hara, K. Y.; Harada, H.; Toh, Y.; Hori, J.

2013-09-01

A gated photomultiplier tube (PMT) assembled with an LaBr3(Ce) detector was applied toward the prompt γ{hbox-}ray measurement of fast neutron capture reactions. Time-of-flight measurements of the neutron capture reactions of Cl and Al were performed using the 46-MeV electron linear accelerator at the Kyoto University Research Reactor Institute (KURRI) as a pulsed neutron source. The photomultiplier gating technique effectively suppressed the saturation of the PMT output and extended the energy region of the TOF measurement.

Design and production of the digital optical module of the KM3NeT project

NASA Astrophysics Data System (ADS)

Leonora, Emanuele; Giordano, Valentina

2017-03-01

The KM3NeT collaboration is building the ARCA and ORCA neutrino telescopes in the depths of the Mediterranean Sea. They will consist of 3-dimensional arrays of photodetectors, called digital optical modules, suspended in the sea by means of vertical string structures, called detection units. The optical modules are composed of a pressure-resistant 17-inch spherical glass vessel, which contains 31 small photomultiplier tubes and all the associated electronics. The multi- photomultiplier solution represents an innovative design with respect to optical modules of all currently operated neutrino telescopes comprising a single large photomultipliers.

Ultra-violet avalanche photodiode based on AlN/GaN periodically-stacked-structure

NASA Astrophysics Data System (ADS)

Wu, Xingzhao; Zheng, Jiyuan; Wang, Lai; Brault, Julien; Matta, Samuel; Hao, Zhibiao; Sun, Changzheng; Xiong, Bing; Luo, Yi; Han, Yianjun; Wang, Jian; Li, Hongtao; Khalfioui, Mohamed A.; Li, Mo; Kang, Jianbin; Li, Qian

2018-02-01

The high-gain photomultiplier tube (PMT) is the most popular method to detect weak ultra-violet signals which attenuate quickly in atmosphere, although the vacuum tube makes it fragile and difficult to integrate. To overcome the disadvantage of PMT, an AlN/GaN periodically-stacked-structure (PSS) avalanche photodiode (APD) has been proposed, finally achieving good quality of high gain and low excessive noise. As there is a deep g valley only in the conduction band of both GaN and AlN, the electron transfers suffering less scattering and thus becomes easier to obtain the threshold of ionization impact. Because of unipolar ionization in the PSS APD, it works in linear mode. Four prototype devices of 5-period, 10-period, 15-period, and 20-period were fabricated to verify that the gain of APD increases exponentially with period number. And in 20-period device, a recorded high and stable gain of 104 was achieved under constant bias. In addition, it is proved both experimentally and theoretically, that temperature stability on gain is significantly improved in PSS APD. And it is found that the resonant enhancement in interfacial ionization may bring significant enhancement of electron ionization performance. To make further progress in PSS APD, the device structure is investigated by simulation. Both the gain and temperature stability are optimized alternatively by a proper design of periodical thickness and AlN layer occupancy.

Characterization of photomultiplier tubes with a realistic model through GPU-boosted simulation

NASA Astrophysics Data System (ADS)

Anthony, M.; Aprile, E.; Grandi, L.; Lin, Q.; Saldanha, R.

2018-02-01

The accurate characterization of a photomultiplier tube (PMT) is crucial in a wide-variety of applications. However, current methods do not give fully accurate representations of the response of a PMT, especially at very low light levels. In this work, we present a new and more realistic model of the response of a PMT, called the cascade model, and use it to characterize two different PMTs at various voltages and light levels. The cascade model is shown to outperform the more common Gaussian model in almost all circumstances and to agree well with a newly introduced model independent approach. The technical and computational challenges of this model are also presented along with the employed solution of developing a robust GPU-based analysis framework for this and other non-analytical models.

Scintillating fibres coupled to silicon photomultiplier prototypes for fast beam monitoring and thin timing detectors

NASA Astrophysics Data System (ADS)

Papa, A.; Kettle, P.-R.; Ripiccini, E.; Rutar, G.

2016-07-01

Several scintillating fibre prototypes (single- and double-layers) made of 250 μm multi-clad square fibres coupled to silicon photomultiplier have been studied using electrons, positrons and muons at different energies. Current measurements show promising results: already for a single fibre layer and minimum ionizing particles we obtain a detection efficiency ≥ 95 % (mean collected light/fibre ≈ 8 phe), a timing resolution of 550 ps/fibre and a foreseen spatial resolution < 100 μm, based on the achieved negligible optical cross-talk between fibres (< 1 %). We will also discuss the performances of a double-layer staggered prototype configuration, for which a full detection efficiency (≥ 99 %) has been measured together with a timing resolution of ≈ 400 ps for double hit events.

Compact Quantum Random Number Generator with Silicon Nanocrystals Light Emitting Device Coupled to a Silicon Photomultiplier

NASA Astrophysics Data System (ADS)

Bisadi, Zahra; Acerbi, Fabio; Fontana, Giorgio; Zorzi, Nicola; Piemonte, Claudio; Pucker, Georg; Pavesi, Lorenzo

2018-02-01

A small-sized photonic quantum random number generator, easy to be implemented in small electronic devices for secure data encryption and other applications, is highly demanding nowadays. Here, we propose a compact configuration with Silicon nanocrystals large area light emitting device (LED) coupled to a Silicon photomultiplier to generate random numbers. The random number generation methodology is based on the photon arrival time and is robust against the non-idealities of the detector and the source of quantum entropy. The raw data show high quality of randomness and pass all the statistical tests in national institute of standards and technology tests (NIST) suite without a post-processing algorithm. The highest bit rate is 0.5 Mbps with the efficiency of 4 bits per detected photon.

Photomultiplier tube reliability study for the HEAO program

NASA Technical Reports Server (NTRS)

Richardson, C.

1974-01-01

Results concerning the research on photomultiplier tubes required for the HEAO program are reported. The general specifications are discussed for providing a series of tests for helping the operational reliability of its application, and for permitting comparison of performance of similar types, from various manufacturers.

Stability and lifetime testing of photomultiplier detectors for the Earth observing system SOLSTICE program

NASA Astrophysics Data System (ADS)

Hadler, Joshua A.; van de Kop, Toni; Drake, Virginia A.; McClintock, William E.; Murphy, John; Rodgers, Paul

1998-10-01

The primary objective of the Earth Observing System (EOS) Solar Stellar Irradiance Comparison Experiment (SOLSTICE) is to accurately measure the absolute value of the solar UV irradiance at the top of the earth's atmosphere for a minimum mission lifetime of 5 years. To meet this objective, SOLSTICE employs a unique design to determine changes in instrument performance by routinely observing a series of early-type stars and comparing the irradiances directly with the solar value. Although the comparison techniques allows us to track instrument performance, the success of the SOLSTICE experiment depends upon photomultiplier detectors which have graceful degradation properties. Therefore, we have established a laboratory program to evaluate the characteristics of photomultiplier tubes which are exposed to long term fluxes similar to those we expected to encounter in flight. Three types of Hamamatsu photomultiplier tubes were tested as candidates for use in the EOS-SOLSTICE project. The results of these studies: pulse height distribution; quantum efficiency; surface maps,; and lifetime analysis are presented in this paper.

Characterization of the ETEL D784UKFLB 11 in. photomultiplier tube

NASA Astrophysics Data System (ADS)

Barros, N.; Kaptanoglu, T.; Kimelman, B.; Klein, J. R.; Moore, E.; Nguyen, J.; Stavreva, K.; Svoboda, R.

2017-04-01

Water Cherenkov and scintillator detectors are a critical tool for neutrino physics. Their large size, low threshold, and low operational cost make them excellent detectors for long baseline neutrino oscillations, proton decay, supernova and solar neutrinos, double beta decay, and ultra-high energy astrophysical neutrinos. Proposals for a new generation of large detectors rely on the availability of large format, fast, cost-effective photomultiplier tubes. The Electron Tubes Enterprises, Ltd (ETEL) D784KFLB 11 in. Photomultiplier Tube has been developed for large neutrino detectors. We have measured the timing characteristics, relative efficiency, and magnetic field sensitivity of the first fifteen prototypes.

Systems for measuring response statistics of gigahertz bandwidth photomultipliers

NASA Technical Reports Server (NTRS)

Abshire, J. B.; Rowe, H. E.

1977-01-01

New systems have been developed for measuring the average impulse response, the pulse-height spectrum, the transit-time statistics as a function of signal level, and the dark-count spectrum of gigahertz bandwidth photomultipliers. Measurements showed that the 0.53 microns pulse used as an optical test source had a 30 picoseconds and less than 70 ps pulse width. Calibration data showed the system resolution to be less than 20 ps for root mean square transit-time measurements. Test data for a static crossed-field photomultiplier showed 2-photoelectron resolution and less than 30-ps time jitter over the 1- to 100-photoelectron range.

SUPPRESSION OF AFTERPULSING IN PHOTOMULTIPLIERS BY GATING THE PHOTOCATHODE

EPA Science Inventory

A number of gating schemes to minimize the long-term afterpulse signal in photomultipliers have been evaluated. Blocking the excitation pulse by gating the photocathode was found to reduce the gate-on afterpulse background by a factor of 230 over that for nongated operation. Thi...

Development of a MEMS-Scale Turbomachinery Based Vacuum Pump

DTIC Science & Technology

2012-06-01

MEMS -SCALE TURBOMACHINERY BASED VACUUM PUMP by Michael J. Shea June 2012 Thesis Advisor: Anthony J. Gannon Second Reader...June 2012 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Development of a MEMS -Scale Turbomachinery Based Vacuum Pump 5...to develop a MEMS scale turbomachinery based vacuum pump. This would allow very high vacuum to be drawn for handheld mass spectroscopy. This

Scintillating fiber-based photon beam profiler for the Jefferson Lab tagged photon beam line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zorn, C.; Barbosa, F.J.; Freyberger, A.

2000-10-01

A scintillating fiber hodoscope has been built for use as a photon beam profiler in the bremsstrahlung tagged photon beam in Hall B of the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The device consists of a linear array of 64 2-2 mm2 scintillating fibers glued to a corresponding set of light guide fibers. Both fiber types use double-clad technology for maximum intensity. The light guide fibers are gently bent into a square array of holes and air-gap coupled to four compact position-sensitive photomultipliers (16 channel Hamamatsu R5900-M16). Custom electronics amplifies and converts the analog outputs to ECL pulses whichmore » are counted by VME-based scalars. The device consisting of the fibers, photomultipliers, and electronics is sealed within a light-tight aluminum box. Two modules make up a beam imaging 2-D system. The system has been tested successfully during an experimental run« less

Electronic gating circuit and ultraviolet laser excitation permit improved dosimeter sensitivity

NASA Technical Reports Server (NTRS)

Eggenberger, D.; King, D.; Longnecker, A.; Schutt, D.

1968-01-01

Standard dosimeter reader, modified by adding an electronic gating circuit to trigger the intensity level photomultiplier, increases readout sensitivity of photoluminescent dosimeter systems. The gating circuit is controlled by a second photomultiplier which senses a short ultraviolet pulse from a laser used to excite the dosimeter.

Limiter Observations during W7-X First Plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wurden, Glen Anthony; Biedermann, C.; Effenberg, F.

During the first operational phase (referred to as OP1.1) of the new Wendelstein 7-X (W7-X) stellarator, five poloidal graphite limiters were mounted on the inboard side of the vacuum vessel, one in each of the five toroidal modules which form the W7-X vacuum vessel. Each limiter consisted of nine specially shaped graphite tiles, designed to conform to the last closed field line geometry in the bean-shaped section of the standard OP1.1 magnetic field configuration (Sunn Pedersen et al 2015 Nucl. Fusion 55 126001). Here, we observed the limiters with multiple infrared and visible camera systems, as well as filtered photomultipliers.more » Power loads are calculated from infrared (IR) temperature measurements using THEODOR, and heating patterns (dual stripes) compare well with field line mapping and EMC3-EIRENE predictions. While the poloidal symmetry of the heat loads was excellent, the toroidal heating pattern showed up to a factor of 2× variation, with peak heat loads on Limiter 1. The total power intercepted by the limiters was up to ~60% of the input ECRH heating power. Calorimetry using bulk tile heating (measured via post-shot IR thermography) on Limiter 3 showed a difference between short high power discharges, and longer lower power ones, with regards to the fraction of energy deposited on the limiters. Finally, fast heating transients, with frequency >1 kHz were detected, and their visibility was enhanced by the presence of surface coatings which developed on the limiters by the end of the campaign.« less

Limiter Observations during W7-X First Plasmas

DOE PAGES

Wurden, Glen Anthony; Biedermann, C.; Effenberg, F.; ...

2017-04-03

During the first operational phase (referred to as OP1.1) of the new Wendelstein 7-X (W7-X) stellarator, five poloidal graphite limiters were mounted on the inboard side of the vacuum vessel, one in each of the five toroidal modules which form the W7-X vacuum vessel. Each limiter consisted of nine specially shaped graphite tiles, designed to conform to the last closed field line geometry in the bean-shaped section of the standard OP1.1 magnetic field configuration (Sunn Pedersen et al 2015 Nucl. Fusion 55 126001). Here, we observed the limiters with multiple infrared and visible camera systems, as well as filtered photomultipliers.more » Power loads are calculated from infrared (IR) temperature measurements using THEODOR, and heating patterns (dual stripes) compare well with field line mapping and EMC3-EIRENE predictions. While the poloidal symmetry of the heat loads was excellent, the toroidal heating pattern showed up to a factor of 2× variation, with peak heat loads on Limiter 1. The total power intercepted by the limiters was up to ~60% of the input ECRH heating power. Calorimetry using bulk tile heating (measured via post-shot IR thermography) on Limiter 3 showed a difference between short high power discharges, and longer lower power ones, with regards to the fraction of energy deposited on the limiters. Finally, fast heating transients, with frequency >1 kHz were detected, and their visibility was enhanced by the presence of surface coatings which developed on the limiters by the end of the campaign.« less

Time-resolved single-photon detection module based on silicon photomultiplier: A novel building block for time-correlated measurement systems

NASA Astrophysics Data System (ADS)

Martinenghi, E.; Di Sieno, L.; Contini, D.; Sanzaro, M.; Pifferi, A.; Dalla Mora, A.

2016-07-01

We present the design and preliminary characterization of the first detection module based on Silicon Photomultiplier (SiPM) tailored for single-photon timing applications. The aim of this work is to demonstrate, thanks to the design of a suitable module, the possibility to easily exploit SiPM in many applications as an interesting detector featuring large active area, similarly to photomultipliers tubes, but keeping the advantages of solid state detectors (high quantum efficiency, low cost, compactness, robustness, low bias voltage, and insensitiveness to magnetic field). The module integrates a cooled SiPM with a total photosensitive area of 1 mm2 together with the suitable avalanche signal read-out circuit, the signal conditioning, the biasing electronics, and a Peltier cooler driver for thermal stabilization. It is able to extract the single-photon timing information with resolution better than 100 ps full-width at half maximum. We verified the effective stabilization in response to external thermal perturbations, thus proving the complete insensitivity of the module to environment temperature variations, which represents a fundamental parameter to profitably use the instrument for real-field applications. We also characterized the single-photon timing resolution, the background noise due to both primary dark count generation and afterpulsing, the single-photon detection efficiency, and the instrument response function shape. The proposed module can become a reliable and cost-effective building block for time-correlated single-photon counting instruments in applications requiring high collection capability of isotropic light and detection efficiency (e.g., fluorescence decay measurements or time-domain diffuse optics systems).

Impulse responses of visible phototubes used in National Ignition Facility neutron time of flight diagnostics.

PubMed

Datte, P S; Eckart, M; Moore, A S; Thompson, W; Vergel de Dios, G

2016-11-01

Neutron-induced visible scintillation in neutron time of flight (NToF) diagnostics at the National Ignition Facility (NIF) is measured with 40 mm single stage micro-channel plate photomultipliers and a 40 mm vacuum photodiode, outside the neutron line of sight. In NIF experiments with 14 MeV neutron yields above Y > 10 × 10 15 these tubes are configured to deliver of order 1 nC of charge in the nominally 5 ns NToF into a 50 Ω load. We have examined a number of 40 mm tubes manufactured by Photek Ltd. of St. Leonards on Sea, UK, to determine possible changes in the instrument impulse response as a function of signal charge delivered in 1 ns. Precision NToF measurements at approximately 20 m require that we characterize changes in the impulse response moments to <40 ps for the first central moment and ∼2% rms for the square root of the second central moment with ∼500 ps value. Detailed results are presented for three different diode configurations.

Imaging photomultiplier array with integrated amplifiers and high-speed USB interfacea)

NASA Astrophysics Data System (ADS)

Blacksell, M.; Wach, J.; Anderson, D.; Howard, J.; Collis, S. M.; Blackwell, B. D.; Andruczyk, D.; James, B. W.

2008-10-01

Multianode photomultiplier tube (PMT) arrays are finding application as convenient high-speed light sensitive devices for plasma imaging. This paper describes the development of a USB-based "plug-n-play" 16-channel PMT camera with 16bits simultaneous acquisition of 16 signal channels at rates up to 2MS/s per channel. The preamplifiers and digital hardware are packaged in a compact housing which incorporates magnetic shielding, on-board generation of the high-voltage PMT bias, an optical filter mount and slits, and F-mount lens adaptor. Triggering, timing, and acquisition are handled by four field-programmable gate arrays (FPGAs) under instruction from a master FPGA controlled by a computer with a LABVIEW interface. We present technical design details and specifications and illustrate performance with high-speed images obtained on the H-1 heliac at the ANU.

Imaging photomultiplier array with integrated amplifiers and high-speed USB interface.

PubMed

Blacksell, M; Wach, J; Anderson, D; Howard, J; Collis, S M; Blackwell, B D; Andruczyk, D; James, B W

2008-10-01

Multianode photomultiplier tube (PMT) arrays are finding application as convenient high-speed light sensitive devices for plasma imaging. This paper describes the development of a USB-based "plug-n-play" 16-channel PMT camera with 16 bits simultaneous acquisition of 16 signal channels at rates up to 2 MSs per channel. The preamplifiers and digital hardware are packaged in a compact housing which incorporates magnetic shielding, on-board generation of the high-voltage PMT bias, an optical filter mount and slits, and F-mount lens adaptor. Triggering, timing, and acquisition are handled by four field-programmable gate arrays (FPGAs) under instruction from a master FPGA controlled by a computer with a LABVIEW interface. We present technical design details and specifications and illustrate performance with high-speed images obtained on the H-1 heliac at the ANU.

Characterization of photomultiplier tubes in a novel operation mode for Secondary Emission Ionization Calorimetry

NASA Astrophysics Data System (ADS)

Tiras, E.; Dilsiz, K.; Ogul, H.; Southwick, D.; Bilki, B.; Wetzel, J.; Nachtman, J.; Onel, Y.; Winn, D.

2016-10-01

Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes have been characterized for use in a Secondary Emission (SE) Ionization Calorimetry study. SE Ionization Calorimetry is a novel technique to measure electromagnetic shower particles in extreme radiation environments. The different operation modes used in these tests were developed by modifying the conventional PMT bias circuit. These modifications were simple changes to the arrangement of the voltage dividers of the baseboard circuits. The PMTs with modified bases, referred to as operating in SE mode, are used as an SE detector module in an SE calorimeter prototype, and placed between absorber materials (Fe, Cu, Pb, W, etc.). Here, the technical design of different operation modes, as well as the characterization measurements of both SE modes and the conventional PMT mode are reported.

The Advanced Gamma-ray Imaging System (AGIS): Focal Plane Detectors

NASA Astrophysics Data System (ADS)

Mukherjee, Reshmi; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Horan, D.; Tajima, H.; Wagner, B.; Williams, D.

2008-04-01

Report of the Focal Plane Instrumentation Working Group, AGIS collaboration: The Advanced Gamma-ray Imaging System (AGIS) is a concept for the next generation instrument in ground-based very high energy gamma-ray astronomy. It has the goal of achieving significant improvement in sensitivity over current experiments. One of the main requirements for AGIS will be to achieve higher angular resolution than current imaging atmospheric Cherenkov telescopes (IACTs). Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to 0.05 deg, below that of current IACTs. Reducing the cost per channel and improving reliability and modularity are other important considerations. Here we present several alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs) and summarize results from feasibility testing by various AGIS photodetector group members.

Fluorescence and phosphorescence of photomultiplier window materials under electron irradiation

NASA Technical Reports Server (NTRS)

Viehmann, W.; Eubanks, A. G.; Bredekamp, J. H.

1974-01-01

The fluorescence and phosphorescence of photomultiplier window materials under electron irradiation were investigated using a Sr-90/Y-90 beta emitter as the electron source. Spectral emission curves of UV grade, optical grade, and electron-irradiated samples of MGF2 and LiF, CaF2, BaF2, sapphire, fused silica, and UV transmitting glasses were obtained over the spectral range of 200 nm to 650 nm. Fluorescence yields, expressed as the number of counts in a solid angle of 2 pi steradian per 1MeV of incident electron energy deposited, were determined on these materials utilizing photomultiplier tubes with cesium telluride, bialkali, and trialkali (S-20) photocathodes, respectively.

On the evaluation of silicon photomultipliers for use as photosensors in liquid xenon detectors

DOE PAGES

Godfrey, B.; Anderson, T.; Breedon, E.; ...

2018-03-26

Silicon photomultipliers (SiPMs) are potential solid-state alternatives to traditional photomultiplier tubes (PMTs) for single-photon detection. In this paper, we report on evaluating SensL MicroFC-10035-SMT SiPMs for their suitability as PMT alternatives. The devices were successfully operated in a liquid-xenon detector, which demonstrates that SiPMs can be used in noble element time projection chambers as photosensors. The devices were also cooled down to 170 K to observe dark count dependence on temperature. No dependencies on the direction of an applied 3.2 kV/cm electric field were observed with respect to dark-count rate, gain, or photon detection efficiency.

On the evaluation of silicon photomultipliers for use as photosensors in liquid xenon detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Godfrey, B.; Anderson, T.; Breedon, E.

Silicon photomultipliers (SiPMs) are potential solid-state alternatives to traditional photomultiplier tubes (PMTs) for single-photon detection. In this paper, we report on evaluating SensL MicroFC-10035-SMT SiPMs for their suitability as PMT alternatives. The devices were successfully operated in a liquid-xenon detector, which demonstrates that SiPMs can be used in noble element time projection chambers as photosensors. The devices were also cooled down to 170 K to observe dark count dependence on temperature. No dependencies on the direction of an applied 3.2 kV/cm electric field were observed with respect to dark-count rate, gain, or photon detection efficiency.

Time-Based Readout of a Silicon Photomultiplier (SiPM) for Time of Flight Positron Emission Tomography (TOF-PET)

NASA Astrophysics Data System (ADS)

Powolny, F.; Auffray, E.; Brunner, S. E.; Garutti, E.; Goettlich, M.; Hillemanns, H.; Jarron, P.; Lecoq, P.; Meyer, T.; Schultz-Coulon, H. C.; Shen, W.; Williams, M. C. S.

2011-06-01

Time of flight (TOF) measurements in positron emission tomography (PET) are very challenging in terms of timing performance, and should ideally achieve less than 100 ps FWHM precision. We present a time-based differential technique to read out silicon photomultipliers (SiPMs) which has less than 20 ps FWHM electronic jitter. The novel readout is a fast front end circuit (NINO) based on a first stage differential current mode amplifier with 20 Ω input resistance. Therefore the amplifier inputs are connected differentially to the SiPM's anode and cathode ports. The leading edge of the output signal provides the time information, while the trailing edge provides the energy information. Based on a Monte Carlo photon-generation model, HSPICE simulations were run with a 3 × 3 mm2 SiPM-model, read out with a differential current amplifier. The results of these simulations are presented here and compared with experimental data obtained with a 3 × 3 × 15 mm3 LSO crystal coupled to a SiPM. The measured time coincidence precision and the limitations in the overall timing accuracy are interpreted using Monte Carlo/SPICE simulation, Poisson statistics, and geometric effects of the crystal.

Characterization of a fiber-less, multichannel optical probe for continuous wave functional near-infrared spectroscopy based on silicon photomultipliers detectors: in-vivo assessment of primary sensorimotor response.

PubMed

Chiarelli, Antonio M; Libertino, Sebania; Zappasodi, Filippo; Mazzillo, Massimo; Pompeo, Francesco Di; Merla, Arcangelo; Lombardo, Salvatore; Fallica, Giorgio

2017-07-01

We report development, testing, and in vivo characterization of a multichannel optical probe for continuous wave (CW) functional near-infrared spectroscopy (fNIRS) that relies on silicon photomultipliers (SiPMs) detectors. SiPMs are cheap, low voltage, and robust semiconductor light detectors with performances analogous to photomultiplier tubes (PMTs). In contrast with PMTs, SiPMs allow direct contact with the head and transfer of the analog signals through thin cables greatly increasing the system flexibility avoiding optical fibers. The coupling of SiPMs and light-emitting diodes (LEDs) made the optical probe lightweight and robust against motion artifacts. After characterization of SiPM performances, which was proven to provide a noise equivalent power below 3 fW, the apparatus was compared through an in vivo experiment to a commercial system relying on laser diodes, PMTs, and optical fibers for light probing and detection. The optical probes were located over the primary sensorimotor cortex and the similarities between the hemodynamic responses to the contralateral motor task were assessed. When compared to other state-of-the-art wearable fNIRS systems, where photodiode detectors are employed, the single photon sensitivity and dynamic range of SiPMs can fully exploit the long and variable interoptode distances needed for correct estimation of brain hemodynamics using CW-fNIRS.

A New Method for Reduction of Photomultiplier Signal-Induced Noise

NASA Technical Reports Server (NTRS)

Koble, Andrea; DeYoung, Russell

2000-01-01

For lidar measurements of ozone, photomultiplier tube (PMT) detector signal-induced noise represents a fundamental problem that complicates the extraction of information from lidar data. A new method is developed to significantly reduce signal-induced noise in lidar receiver PMT detectors. The electron optics of the lidar photomultiplier detector is modified to filter the source of signal-induced noise. A mesh electrode external to the PMT is utilized to control photoemission and disorient electron trajectories from the photocathode to the first dynode. Experiments were taken both with simulated and actual lidar return signals at Langley Research Center. Results show at least 40 percent more accurate ozone number density values with a mesh voltage of 60 V applied than with no voltage applied.

Development and verification of an innovative photomultiplier calibration system with a 10-fold increase in photometer resolution

NASA Astrophysics Data System (ADS)

Jiang, Shyh-Biau; Yeh, Tse-Liang; Chen, Li-Wu; Liu, Jann-Yenq; Yu, Ming-Hsuan; Huang, Yu-Qin; Chiang, Chen-Kiang; Chou, Chung-Jen

2018-05-01

In this study, we construct a photomultiplier calibration system. This calibration system can help scientists measuring and establishing the characteristic curve of the photon count versus light intensity. The system uses an innovative 10-fold optical attenuator to enable an optical power meter to calibrate photomultiplier tubes which have the resolution being much greater than that of the optical power meter. A simulation is firstly conducted to validate the feasibility of the system, and then the system construction, including optical design, circuit design, and software algorithm, is realized. The simulation generally agrees with measurement data of the constructed system, which are further used to establish the characteristic curve of the photon count versus light intensity.

Notes on the design of experiments and beam diagnostics with synchrotron light detected by a gated photomultiplier for the Fermilab superconducting electron linac and for the Integrable Optics Test Accelerator (IOTA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stancari, Giulio; Romanov, Aleksandr; Ruan, Jinhao

We outline the design of beam experiments for the electron linac at the Fermilab Accelerator Science and Technology (FAST) facility and for the Integrable Optics Test Accelerator (IOTA), based on synchrotron light emitted by the electrons in bend dipoles, detected with gated microchannel-plate photomultipliers (MCP-PMTs). The system can be used both for beam diagnostics (e.g., beam intensity with full dynamic range, turn-by-turn beam vibrations, etc.) and for scientific experiments, such as the direct observation of the time structure of the radiation emitted by single electrons in a storage ring. The similarity between photon pulses and spectrum at the downstream endmore » of the electron linac and in the IOTA ring allows one to test the apparatus during commissioning of the linac.« less

Modeling scintillator and WLS fiber signals for fast Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Sánchez, F. A.; Medina-Tanco, G.

2010-08-01

In this work we present a fast, robust and flexible procedure to simulate electronic signals of scintillator units: plastic scintillator material embedded with a wavelength shifter optical fiber coupled to a photo-multiplier tube which, in turn, is plugged to a front-end electronic board. The simple rationale behind the simulation chain allows to adapt the procedure to a broad range of detectors based on that kind of units. We show that, in order to produce realistic results, the simulation parameters can be properly calibrated against laboratory measurements and used thereafter as input of the simulations. Simulated signals of atmospheric background cosmic ray muons are presented and their main features analyzed and validated using actual measured data. Conversely, for any given practical application, the present simulation scheme can be used to find an adequate combination of photo-multiplier tube and optical fiber at the prototyping stage.

The electronics readout and data acquisition system of the KM3NeT neutrino telescope node

DOE Office of Scientific and Technical Information (OSTI.GOV)

Real, Diego; Collaboration: KM3NeT Collaboration

2014-11-18

The KM3NeT neutrino telescope will be composed by tens of thousands of glass spheres, called Digital Optical Module (DOM), each of them containing 31 PMTs of small photocathode area (3'). The readout and data acquisition system of KM3NeT have to collect, treat and send to shore, in an economic way, the enormous amount of data produced by the photomultipliers and at the same time to provide time synchronization between each DOM at the level of 1 ns. It is described in the present article the Central Logic Board, that integrates the Time to Digital Converters and the White Rabbit protocolmore » used for the DOM synchronization in a transparent way, the Power Board used in the DOM, the PMT base to readout the photomultipliers and the respective collecting boards, the so called Octopus Board.« less

The research on the temperature measurement technology of aluminum atomic emission spectroscopy

NASA Astrophysics Data System (ADS)

Hu, Xiaotao; Hao, Xiaojian; Tang, Huijuan; Sun, Yongkai

2018-02-01

Aimed to the testing requirement of the transient high temperature in the bore of barrel weapon, which has the problems of high temperature, high pressure, high overload and narrow adverse environment, the photoelectric pyrometer was researched based on the temperature measurement technology of double line of atomic emission spectrum and storage measurement technology, which used silicon photomultiplier. Al I 690.6nm and 708.5nm were selected as the temperature measurement element spectral lines, spectral line intensity was converted into a voltage value by silicon photomultiplier, the temperature was obtained through the ratio of two spectrum lines. The temperature is measured by the photoelectric thermometer and the infrared thermometer when heating aluminum by oxyhydrogen flame, and the relative error was 1.75%. Results show the temperature dependence of the two methods is better, and prove the feasibility of the method.

Gamma-ray spectroscopy at MHz counting rates with a compact LaBr3 detector and silicon photomultipliers for fusion plasma applications.

PubMed

Nocente, M; Rigamonti, D; Perseo, V; Tardocchi, M; Boltruczyk, G; Broslawski, A; Cremona, A; Croci, G; Gosk, M; Kiptily, V; Korolczuk, S; Mazzocco, M; Muraro, A; Strano, E; Zychor, I; Gorini, G

2016-11-01

Gamma-ray spectroscopy measurements at MHz counting rates have been carried out, for the first time, with a compact spectrometer based on a LaBr 3 scintillator and silicon photomultipliers. The instrument, which is also insensitive to magnetic fields, has been developed in view of the upgrade of the gamma-ray camera diagnostic for α particle measurements in deuterium-tritium plasmas of the Joint European Torus. Spectra were measured up to 2.9 MHz with a projected energy resolution of 3%-4% in the 3-5 MeV range, of interest for fast ion physics studies in fusion plasmas. The results reported here pave the way to first time measurements of the confined α particle profile in high power plasmas of the next deuterium-tritium campaign at the Joint European Torus.

Time-resolved single-photon detection module based on silicon photomultiplier: A novel building block for time-correlated measurement systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinenghi, E., E-mail: edoardo.martinenghi@polimi.it; Di Sieno, L.; Contini, D.

2016-07-15

We present the design and preliminary characterization of the first detection module based on Silicon Photomultiplier (SiPM) tailored for single-photon timing applications. The aim of this work is to demonstrate, thanks to the design of a suitable module, the possibility to easily exploit SiPM in many applications as an interesting detector featuring large active area, similarly to photomultipliers tubes, but keeping the advantages of solid state detectors (high quantum efficiency, low cost, compactness, robustness, low bias voltage, and insensitiveness to magnetic field). The module integrates a cooled SiPM with a total photosensitive area of 1 mm{sup 2} together with themore » suitable avalanche signal read-out circuit, the signal conditioning, the biasing electronics, and a Peltier cooler driver for thermal stabilization. It is able to extract the single-photon timing information with resolution better than 100 ps full-width at half maximum. We verified the effective stabilization in response to external thermal perturbations, thus proving the complete insensitivity of the module to environment temperature variations, which represents a fundamental parameter to profitably use the instrument for real-field applications. We also characterized the single-photon timing resolution, the background noise due to both primary dark count generation and afterpulsing, the single-photon detection efficiency, and the instrument response function shape. The proposed module can become a reliable and cost-effective building block for time-correlated single-photon counting instruments in applications requiring high collection capability of isotropic light and detection efficiency (e.g., fluorescence decay measurements or time-domain diffuse optics systems).« less

An integrated general purpose SiPM based optical module with a high dynamic range

NASA Astrophysics Data System (ADS)

Bretz, T.; Engel, R.; Hebbeker, T.; Kemp, J.; Middendorf, L.; Peters, C.; Schumacher, J.; Šmída, R.; Veberič, D.

2018-06-01

Silicon photomultipliers (SiPMs) are semiconductor-based light-sensors offering a high gain, a mechanically and optically robust design and high photon detection efficiency. Due to these characteristics, they started to replace conventional photomultiplier tubes in many applications in recent years. This paper presents an optical module based on SiPMs designed for the application in scintillators as well as lab measurements. The module hosts the SiPM bias voltage supply and three pre-amplifiers with different gain levels to exploit the full dynamic range of the SiPMs. Two SiPMs, read-out in parallel, are equipped with light guides to increase the sensitive area. The light guides are optimized for the read-out of wavelength shifting fibers as used in many plastic scintillator detectors. The optical and electrical performance of the module is characterized in detail in laboratory measurements. Prototypes have been installed and tested in a modified version of the Scintillator Surface Detector developed for AugerPrime, the upgrade of the Pierre Auger Observatory. The SiPM module is operated in the Argentinian Pampas and first data proves its usability in such harsh environments.

Neutron position-sensitive scintillation detector

DOEpatents

Strauss, Michael G.; Brenner, Raul

1984-01-01

A device is provided for mapping one- and two-dimensional distributions of neutron-positions in a scintillation detector. The device consists of a lithium glass scintillator coupled by an air gap and a light coupler to an array of photomultipliers. The air gap concentrates light flashes from the scintillator, whereas the light coupler disperses this concentrated light to a predetermined fraction of the photomultiplier tube array.

Turbulence measurements using the laser Doppler velocimeter

NASA Technical Reports Server (NTRS)

Dunning, J. W., Jr.; Berman, N. S.

1971-01-01

The photomultiplier signal representing the axial velocity of water within a glass pipe is examined. It is shown that with proper analysis of the photomultiplier signal, the turbulent information that can be obtained in liquid flows is equivalent to recent hot film studies. In shear flows the signal from the laser Doppler velocimeter contains additional information which may be related to the average shear.

The ANTARES optical beacon system

NASA Astrophysics Data System (ADS)

Ageron, M.; Aguilar, J. A.; Albert, A.; Ameli, F.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardellier-Desages, F.; Aslanides, E.; Aubert, J.-J.; Auer, R.; Barbarito, E.; Basa, S.; Battaglieri, M.; Becherini, Y.; Beltramelli, J.; Bertin, V.; Bigi, A.; Billault, M.; Blaes, R.; de Botton, N.; Bouwhuis, M. C.; Bradbury, S. M.; Bruijn, R.; Brunner, J.; Burgio, G. F.; Busto, J.; Cafagna, F.; Caillat, L.; Calzas, A.; Capone, A.; Caponetto, L.; Carmona, E.; Carr, J.; Cartwright, S. L.; Castel, D.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, P.; Chauchot, P.; Chiarusi, T.; Circella, M.; Colnard, C.; Compère, C.; Coniglione, R.; Cottini, N.; Coyle, P.; Cuneo, S.; Cussatlegras, A.-S.; Damy, G.; van Dantzig, R.; de Bonis, G.; de Marzo, C.; de Vita, R.; Dekeyser, I.; Delagnes, E.; Denans, D.; Deschamps, A.; Destelle, J.-J.; Dinkespieler, B.; Distefano, C.; Donzaud, C.; Drogou, J.-F.; Druillole, F.; Durand, D.; Ernenwein, J.-P.; Escoffier, S.; Falchini, E.; Favard, S.; Fehr, F.; Feinstein, F.; Ferry, S.; Fiorello, C.; Flaminio, V.; Fratini, K.; Fuda, J.-L.; Galeotti, S.; Gallone, J.-M.; Giacomelli, G.; Girard, N.; Gojak, C.; Goret, Ph.; Graf, K.; Hallewell, G.; Harakeh, M. N.; Hartmann, B.; Heijboer, A.; Heine, E.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hoffman, C.; Hogenbirk, J.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jouvenot, F.; Kalantar-Nayestanaki, N.; Kappes, A.; Karg, T.; Katz, U.; Keller, P.; Kok, E.; Kok, H.; Kooijman, P.; Kopper, C.; Korolkova, E. V.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kudryavstev, V. A.; Lagier, P.; Lahmann, R.; Lamanna, G.; Lamare, P.; Lambard, G.; Languillat, J.-C.; Laschinsky, H.; Lavalle, J.; Le Guen, Y.; Le Provost, H.; Le van Suu, A.; Lefèvre, D.; Legou, T.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Marcelin, M.; Margiotta, A.; Masullo, R.; Mazéas, F.; Mazure, A.; McMillan, J. E.; Megna, R.; Melissas, M.; Migneco, E.; Milovanovic, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Musumeci, M.; Naumann-Godo, M.; Naumann, C.; Niess, V.; Noble, T.; Olivetto, C.; Ostasch, R.; Palanque-Delabrouille, N.; Payre, P.; Peek, H.; Perez, A.; Petta, C.; Piattelli, P.; Pillet, R.; Pineau, J.-P.; Poinsignon, J.; Popa, V.; Pradier, T.; Racca, C.; Randazzo, N.; van Randwijk, J.; Real, D.; van Rens, B.; Réthoré, F.; Rewiersma, P.; Riccobene, G.; Rigaud, V.; Ripani, M.; Roca, V.; Roda, C.; Rolin, J. F.; Rose, H. J.; Rostovtsev, A.; Roux, J.; Ruppi, M.; Russo, G. V.; Rusydi, G.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schuller, J.-P.; Shanidze, R.; Sokalski, I.; Spona, T.; Spurio, M.; van der Steenhoven, G.; Stolarczyk, T.; Streeb, K.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Terreni, G.; Thompson, L. F.; Urbano, F.; Valdy, P.; Valente, V.; Vallage, B.; Vaudaine, G.; Venekamp, G.; Verlaat, B.; Vernin, P.; de Vries-Uiterweerd, G.; van Wijk, R.; Wijnker, G.; de Witt Huberts, P.; Wobbe, G.; de Wolf, E.; Yao, A.-F.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zúñiga, J.

2007-08-01

ANTARES is a neutrino telescope being deployed in the Mediterranean Sea. It consists of a three-dimensional array of photomultiplier tubes that can detect the Cherenkov light induced by charged particles produced in the interactions of neutrinos with the surrounding medium. High angular resolution can be achieved, in particular, when a muon is produced, provided that the Cherenkov photons are detected with sufficient timing precision. Considerations of the intrinsic time uncertainties stemming from the transit time spread in the photomultiplier tubes and the mechanism of transmission of light in sea water lead to the conclusion that a relative time accuracy of the order of 0.5 ns is desirable. Accordingly, different time calibration systems have been developed for the ANTARES telescope. In this article, a system based on Optical Beacons, a set of external and well-controlled pulsed light sources located throughout the detector, is described. This calibration system takes into account the optical properties of sea water, which is used as the detection volume of the ANTARES telescope. The design, tests, construction and first results of the two types of beacons, LED and laser-based, are presented.

Status of the NectarCAM camera project

NASA Astrophysics Data System (ADS)

Glicenstein, J.-F.; Barcelo, M.; Barrio, J.-A.; Blanch, O.; Boix, J.; Bolmont, J.; Boutonnet, C.; Brun, P.; Chabanne, E.; Champion, C.; Colonges, S.; Corona, P.; Courty, B.; Delagnes, E.; Delgado, C.; Diaz, C.; Ernenwein, J.-P.; Fegan, S.; Ferreira, O.; Fesquet, M.; Fontaine, G.; Fouque, N.; Henault, F.; Gascón, D.; Giebels, B.; Herranz, D.; Hermel, R.; Hoffmann, D.; Horan, D.; Houles, J.; Jean, P.; Karkar, S.; Knödlseder, J.; Martinez, G.; Lamanna, G.; LeFlour, T.; Lévêque, A.; Lopez-Coto, R.; Louis, F.; Moudden, Y.; Moulin, E.; Nayman, P.; Nunio, F.; Olive, J.-F.; Panazol, J.-L.; Pavy, S.; Petrucci, P.-O.; Punch, M.; Prast, Julie; Ramon, P.; Rateau, S.; Ribó, M.; Rosier-Lees, S.; Sanuy, A.; Sizun, P.; Sieiro, J.; Sulanke, K.-H.; Tavernet, J.-P.; Tejedor, L. A.; Toussenel, F.; Vasileiadis, G.; Voisin, V.; Waegebert, V.; Zurbach, C.

2014-07-01

NectarCAM is a camera designed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) covering the central energy range 100 GeV to 30 TeV. It has a modular design based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 7 to 8 degrees. Each module includes the photomultiplier bases, High Voltage supply, pre-amplifier, trigger, readout and Thernet transceiver. Events recorded last between a few nanoseconds and tens of nanoseconds. A flexible trigger scheme allows to read out very long events. NectarCAM can sustain a data rate of 10 kHz. The camera concept, the design and tests of the various subcomponents and results of thermal and electrical prototypes are presented. The design includes the mechanical structure, the cooling of electronics, read-out, clock distribution, slow control, data-acquisition, trigger, monitoring and services. A 133-pixel prototype with full scale mechanics, cooling, data acquisition and slow control will be built at the end of 2014.

A FLUKA simulation of the KLOE electromagnetic calorimeter

NASA Astrophysics Data System (ADS)

Di Micco, B.; Branchini, P.; Ferrari, A.; Loffredo, S.; Passeri, A.; Patera, V.

2007-10-01

We present the simulation of the KLOE calorimeter with the FLUKA Monte Carlo program. The response of the detector to electromagnetic showers has been studied and compared with the publicly available KLOE data. The energy and the time resolution of the electromagnetic clusters is in good agreement with the data. The simulation has been also used to study a possible improvement of the KLOE calorimeter using multianode photo-multipliers. An HAMAMATSU R7600-M16 photomultiplier has been assembled in order to determine the whole cross talk matrix that has been included in the simulation. The cross talk matrix takes into account the effects of a realistic photo-multiplier's electronics and of its coupling to the active material. The performance of the modified readout has been compared to the usual KLOE configuration.

Turbulence measurements using the laser Doppler velocimeter.

NASA Technical Reports Server (NTRS)

Dunning, J. W., Jr.; Berman, N. S.

1971-01-01

The photomultiplier signal representing the axial velocity of water within a glass pipe is considered. It is shown that with proper analysis of the photomultiplier signal, the turbulent information that can be obtained in liquid flows is equivalent to results obtained in recent hot film studies. In shear flows the signal from the laser Doppler velocimeter contains additional information which may be related to the average shear.

Semiconductor superlattice photodetectors

NASA Technical Reports Server (NTRS)

Chuang, S. L.; Hess, K.; Coleman, J. J.; Leburton, J. P.

1986-01-01

During the past half-year, the research effort centered on further investigating both the new superlattice photomultiplier with tunneling-assisted impact ionization and the photodetector based on the real space transfer mechanism. A brief outline of the current status of these projects is presented. Detailed analyses are included in Appendices A and B. New results of the tunneling-assisted impact ionization are presented.

Supernovae studied with a ground level atmospheric fluorescence

NASA Technical Reports Server (NTRS)

Bertsch, D. L.

1972-01-01

A monitoring experiment was undertaken late 1968 to search for photon bursts of extraterrestrial origin. The experiment and the results of the observations to date are summarized. The method of detection employs ground-based photomultiplier tubes which are sensitive to the secondary fluorescence light that would be produced when the primary pulse is absorbed in the atmosphere.

Silicon photomultipliers for scintillating trackers

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Low Power Photomultiplier Tube Circuit And Method Thereor

DOEpatents

Bochenski, Edwin B.; Skinner, Jack L.; Dentinger, Paul M.; Lindblom, Scott C.

2006-04-18

An electrical circuit for a photomultiplier tube (PMT) is disclosed that reduces power consumption to a point where the PMT may be powered for extended periods with a battery. More specifically, the invention concerns a PMT circuit comprising a low leakage switch and a high voltage capacitor positioned between a resistive divider and each of the PMT dynodes, and a low power control scheme for recharging the capacitors.

Latest generation of ASICs for photodetector readout

NASA Astrophysics Data System (ADS)

Seguin-Moreau, N.

2013-08-01

The OMEGA microelectronics group has designed a new generation of multichannel integrated circuits, the "ROC" family, in AustrianMicroSystem (AMS) SiGe 0.35 μm technology to read out signals from various families of photodetectors. The chip named MAROC (standing for Multi Anode ReadOut Chip) has been designed to read out MultiAnode Photomultipliers (MAPMT), Photomultiplier ARray In SiGe ReadOut Chip (PARISROC) to read out Photomultipliers (PMTs) and SiPM Integrated ReadOut Chip (SPIROC) to readout Silicon PhotoMultiplier (SiPM) detectors and which was the first ASIC to do so. The three of them fulfill the stringent requirements of the future photodetectors, in particular in terms of low noise, radiation hardness, large dynamic range, high density and high speed while keeping low power thanks to the SiGe technology. These multi-channel ASICs are real System on Chip (SoC) as they provide charge, time and photon-counting information which are digitized internally. Their complexity and versatility enable innovative frontier detectors and also cover spin off of these detectors in adjacent fields such as medical or material imaging as well as smart detectors. In this presentation, the three ASIC architectures and test results will be described to give a general panorama of the "ROC" chips.

Results from the Solar Hidden Photon Search (SHIPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, Matthias; Schneide, Magnus; Susol, Jaroslaw

We present the results of a search for transversely polarised hidden photons (HPs) with ∼ 3 eV energies emitted from the Sun. These hypothetical particles, known also as paraphotons or dark sector photons, are theoretically well motivated for example by string theory inspired extensions of the Standard Model. Solar HPs of sub-eV mass can convert into photons of the same energy (photon ↔ HP oscillations are similar to neutrino flavour oscillations). At SHIPS this would take place inside a long light-tight high-vacuum tube, which tracks the Sun. The generated photons would then be focused into a low-noise photomultiplier at the far end ofmore » the tube. Our analysis of 330 h of data (and 330 h of background characterisation) reveals no signal of photons from solar hidden photon conversion. We estimate the rate of newly generated photons due to this conversion to be smaller than 25 mHz/m{sup 2} at the 95% C.L . Using this and a recent model of solar HP emission, we set stringent constraints on χ, the coupling constant between HPs and photons, as a function of the HP mass.« less

Results from the Solar Hidden Photon Search (SHIPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, Matthias; Knabbe, Ernst-Axel; Lindner, Axel

We present the results of a search for transversely polarised hidden photons (HPs) with ∼3 eV energies emitted from the Sun. These hypothetical particles, known also as paraphotons or dark sector photons, are theoretically well motivated for example by string theory inspired extensions of the Standard Model. Solar HPs of sub-eV mass can convert into photons of the same energy (photon ↔ HP oscillations are similar to neutrino flavour oscillations). At SHIPS this would take place inside a long light-tight high-vacuum tube, which tracks the Sun. The generated photons would then be focused into a low-noise photomultiplier at the farmore » end of the tube. Our analysis of 330 h of data (and 330 h of background characterisation) reveals no signal of photons from solar hidden photon conversion. We estimate the rate of newly generated photons due to this conversion to be smaller than 25 mHz/m{sup 2} at the 95% C.L. Using this and a recent model of solar HP emission, we set stringent constraints on χ, the coupling constant between HPs and photons, as a function of the HP mass.« less

Direct Measurement of Impurity Transport in a Field Reversed Configuration

NASA Astrophysics Data System (ADS)

Roche, T.; Bolte, N.; Heidbrink, W. W.; McWilliams, R.; Wessel, F.

2011-10-01

An optical tomography system has been developed and implemented in the Flux Coil Generated Field Reversed Configuration (FCG-FRC) at Tri Alpha Energy. Sixteen chords view ~ 35 % of the FRC at the mid-plane. The chords are arranged in two identical fans of eight chords each. To measure transport of an impurity species, argon, an FRC is generated using either Nitrogen or Deuterium as the primary species. A puff valve is activated prior to the shot such that the argon begins to bleed in to the vacuum chamber as the FRC is formed. The gas is puffed at the optimal location for tomographic reconstruction. Each chord is collimated to illuminate a fiber optic cable which is fed to an array of photomultiplier tubes which are fitted with neutral density and band pass filters to allow the appropriate amount of light from the emitting, singly ionized, argon at 434 . 8 nm to be measured. Using a preliminary assumption that density of argon is proportional to light intensity gathered data have been used to reconstruct density profiles. These profiles often peak near the field null. The data are being analyzed to determine diffusive and convective transport coefficients.

TU-H-CAMPUS-TeP2-03: High Sensitivity and High Resolution Fiber Based Micro-Detector for Sub-Millimeter Preclinical Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izaguirre, E; Pokhrel, S; Knewtson, T

2016-06-15

Purpose: Current precision of small animal and cell micro-irradiators has continuously increased during the past years. Currently, preclinical irradiators can deliver sub-millimeter fields with micrometric precision but there are no water equivalent dosimeters to determine small field profiles and dose in the orthovoltage range of energies with micrometric resolution and precision. We have developed a fiber based micro-dosimeter with the resolution and dosimetric accuracy required for radiobiological research. Methods: We constructed two prototypes of micro-dosimeters based on different compositions of fiber scintillators to study the spatial resolution and dosimetric precision of small animal and cell micro-irradiators. The first has greenmore » output and the second has blue output. The blue output dosimeter has the highest sensitivity because it matches the spectral sensitivity of silicon photomultipliers. A blue detector with 500um cross section was built and tested respect to a CC01 ion chamber, film, and the 1500um green output detector. Orthovoltage fields from 1×1mm2 to 5×5mm2 were used for detector characteristics comparison. Results: The blue fiber dosimeter shows great agreement with films and matches dose measurements with the gold-standard ion chamber for 5×5mm2 fields. The detector has the appropriate sensitivity to measure fields from 1×1mm2 to larger sizes with a 1% dosimetric accuracy. The spatial resolution is in the sub-millimeter range and the spectral matching with the photomultiplier allows reducing the sensor cross section even further than the presented prototype. These results suggest that scintillating fibers combined with silicon photomultipliers is the appropriate technology to pursue micro-dosimetry for small animals and disperse cell samples. Conclusion: The constructed detectors establish a new landmark for the resolution and sensitivity of fiber based microdetectors. The validation of the detector in our small animal and cell irradiator shows that they are appropriate for preclinical and micro single cell irradiation quality assurance and dosimetry.« less

Large surface scintillators as base of impact point detectors and their application in Space Weather

NASA Astrophysics Data System (ADS)

Ayuso, Sindulfo; Medina, José; Gómez-Herrero, Raul; José Blanco, Juan; García-Tejedor, Ignacio; García-Población, Oscar; Díaz-Romeral, Gonzalo

2016-04-01

The use of a pile of two 100 cm x 100 cm x 5 cm BC-400 organic scintillators is proposed as ground-based cosmic ray detector able to provide directional information on the incident muons. The challenge is to get in real time the muon impact point on the scintillator and its arrival direction using as few Photomultiplier Tubes (PMTs) as possible. The instrument is based on the dependence of attenuation of light with the traversed distance in each scintillator. For the time being, four photomultiplier tubes gather the light through the lateral faces (100 cm x 5 cm) of the scintillator. Several experiments have already been carried out. The results show how data contain information about the muon trajectory through the scintillator. This information can be extracted using the pulse heights collected by the PMTs working in coincidence mode. Reliability and accuracy of results strongly depend on the number of PMTs used and mainly on their appropriate geometrical arrangement with regard to the scintillator. In order to determine the optimal position and the minimum number of PMTs required, a Montecarlo simulation code has been developed. Preliminary experimental and simulation results are presented and the potential of the system for space weather monitoring is discussed.

Photodetector timing research at Fermilab

DOE PAGES

Ramberg, E.; Ronzhin, A.; Albrow, M.; ...

2011-01-01

We describe here the outlines of research undertaken by Fermilab into timing characteristics of photodetectors. We describe our experimental method and give benchtop results on the timing resolution of micro-channel plate photomultipliers (MCP-PMT) and silicon photomultipliers (SiPM). In addition, we describe results of various configurations of these detectors, along with quartz radiators, in particle test beams at Fermilab. Results for timing of scintillator light using the DRS4 high speed digitizer are also presented.

The data acquisition system for the ANTARES neutrino telescope

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Albert, A.; Ameli, F.; Anghinolfi, M.; Anton, G.; Anvar, S.; Aslanides, E.; Aubert, J.-J.; Barbarito, E.; Basa, S.; Battaglieri, M.; Becherini, Y.; Bellotti, R.; Beltramelli, J.; Bertin, V.; Bigi, A.; Billault, M.; Blaes, R.; de Botton, N.; Bouwhuis, M. C.; Bradbury, S. M.; Bruijn, R.; Brunner, J.; Burgio, G. F.; Busto, J.; Cafagna, F.; Caillat, L.; Calzas, A.; Capone, A.; Caponetto, L.; Carmona, E.; Carr, J.; Cartwright, S. L.; Castel, D.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Ceres, A.; Charvis, P.; Chauchot, P.; Chiarusi, T.; Circella, M.; Colnard, C.; Compère, C.; Coniglione, R.; Cottini, N.; Coyle, P.; Cuneo, S.; Cussatlegras, A.-S.; Damy, G.; van Dantzig, R.; de Marzo, C.; Dekeyser, I.; Delagnes, E.; Denans, D.; Deschamps, A.; Dessages-Ardellier, F.; Destelle, J.-J.; Dinkespieler, B.; Distefano, C.; Donzaud, C.; Drogou, J.-F.; Druillole, F.; Durand, D.; Ernenwein, J.-P.; Escoffier, S.; Falchini, E.; Favard, S.; Feinstein, F.; Ferry, S.; Festy, D.; Fiorello, C.; Flaminio, V.; Galeotti, S.; Gallone, J.-M.; Giacomelli, G.; Girard, N.; Gojak, C.; Goret, Ph.; Graf, K.; Hallewell, G.; Harakeh, M. N.; Hartmann, B.; Heijboer, A.; Heine, E.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hoffman, C.; Hogenbirk, J.; Hubbard, J. R.; Jaquet, M.; Jaspers, M.; de Jong, M.; Jouvenot, F.; Kalantar-Nayestanaki, N.; Kappes, A.; Karg, T.; Karkar, S.; Katz, U.; Keller, P.; Kok, H.; Kooijman, P.; Kopper, C.; Korolkova, E. V.; Kouchner, A.; Kretschmer, W.; Kruijer, A.; Kuch, S.; Kudryavstev, V. A.; Lachartre, D.; Lafoux, H.; Lagier, P.; Lahmann, R.; Lamanna, G.; Lamare, P.; Languillat, J. C.; Laschinsky, H.; Le Guen, Y.; Le Provost, H.; Le van Suu, A.; Legou, T.; Lim, G.; Lo Nigro, L.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Louis, F.; Lucarelli, F.; Lyashuk, V.; Marcelin, M.; Margiotta, A.; Masullo, R.; Mazéas, F.; Mazure, A.; McMillan, J. E.; Megna, R.; Melissas, M.; Migneco, E.; Milovanovic, A.; Mongelli, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Musumeci, M.; Naumann, C.; Naumann-Godo, M.; Niess, V.; Olivetto, C.; Ostasch, R.; Palanque-Delabrouille, N.; Payre, P.; Peek, H.; Petta, C.; Piattelli, P.; Pineau, J.-P.; Poinsignon, J.; Popa, V.; Pradier, T.; Racca, C.; Randazzo, N.; van Randwijk, J.; Real, D.; van Rens, B.; Réthoré, F.; Rewiersma, P.; Riccobene, G.; Rigaud, V.; Ripani, M.; Roca, V.; Roda, C.; Rolin, J. F.; Romita, M.; Rose, H. J.; Rostovtsev, A.; Roux, J.; Ruppi, M.; Russo, G. V.; Salesa, F.; Salomon, K.; Sapienza, P.; Schmitt, F.; Schuller, J.-P.; Shanidze, R.; Sokalski, I.; Spona, T.; Spurio, M.; van der Steenhoven, G.; Stolarczyk, T.; Streeb, K.; Stubert, D.; Sulak, L.; Taiuti, M.; Tamburini, C.; Tao, C.; Terreni, G.; Thompson, L. F.; Valdy, P.; Valente, V.; Vallage, B.; Venekamp, G.; Verlaat, B.; Vernin, P.; de Vita, R.; de Vries, G.; van Wijk, R.; de Witt Huberts, P.; Wobbe, G.; de Wolf, E.; Yao, A.-F.; Zaborov, D.; Zaccone, H.; Zornoza, J. D.; Zúñiga, J.

2007-01-01

The ANTARES neutrino telescope is being constructed in the Mediterranean Sea. It consists of a large three-dimensional array of photo-multiplier tubes. The data acquisition system of the detector takes care of the digitisation of the photo-multiplier tube signals, data transport, data filtering, and data storage. The detector is operated using a control program interfaced with all elements. The design and the implementation of the data acquisition system are described.

Adaptive algorithms of position and energy reconstruction in Anger-camera type detectors: experimental data processing in ANTS

NASA Astrophysics Data System (ADS)

Morozov, A.; Defendi, I.; Engels, R.; Fraga, F. A. F.; Fraga, M. M. F. R.; Gongadze, A.; Guerard, B.; Jurkovic, M.; Kemmerling, G.; Manzin, G.; Margato, L. M. S.; Niko, H.; Pereira, L.; Petrillo, C.; Peyaud, A.; Piscitelli, F.; Raspino, D.; Rhodes, N. J.; Sacchetti, F.; Schooneveld, E. M.; Solovov, V.; Van Esch, P.; Zeitelhack, K.

2013-05-01

The software package ANTS (Anger-camera type Neutron detector: Toolkit for Simulations), developed for simulation of Anger-type gaseous detectors for thermal neutron imaging was extended to include a module for experimental data processing. Data recorded with a sensor array containing up to 100 photomultiplier tubes (PMT) or silicon photomultipliers (SiPM) in a custom configuration can be loaded and the positions and energies of the events can be reconstructed using the Center-of-Gravity, Maximum Likelihood or Least Squares algorithm. A particular strength of the new module is the ability to reconstruct the light response functions and relative gains of the photomultipliers from flood field illumination data using adaptive algorithms. The performance of the module is demonstrated with simulated data generated in ANTS and experimental data recorded with a 19 PMT neutron detector. The package executables are publicly available at http://coimbra.lip.pt/~andrei/

Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment

DOE PAGES

Aprile, E.; Agostini, F.; Alfonsi, M.; ...

2015-11-23

The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, wemore » detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment.« less

Detection of Cherenkov Photons with Multi-Anode Photomultipliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salazar, H.; Moreno, E.; Murrieta, T.

2006-09-25

The present paper describes the laboratory course given at the X Mexican Workshop on Particles and Fields. We describe the setup and procedure used to measure the Cherenkov circles produced by cosmic muons upon traversal of a simple glass radiator system. The main purpose of this exercise is to introduce the students to work with multi-anode photomultipliers such as the one used for this experiment (Hamamatsu R5900-M64), with which measurements requiring position sensitive detection of single photons can be successfully performed. We present a short introduction to multi-anode photomultipliers (MAPMT) and describe the setup and the procedure used to measuremore » the response of a MAPMT to a uniform source of light. Finally, we describe the setup and procedure used to measure the Cherenkov circles produced by cosmic muons upon traversal of a simple glass radiator system.« less

Silicon Photomultiplier Characterization for sPHENIX Calorimeters

NASA Astrophysics Data System (ADS)

Tanner, Meghan; Skoby, Michael; Aidala, Christine; Sphenix Collaboration

2016-09-01

Silicon photomultipliers (SiPMs) are preferable to photomultiplier tubes due to their small size, insensitivity to magnetic fields, low operating voltage, and capability of detecting single photons. The sPHENIX collaboration at RHIC will use SiPMs in their proposed electromagnetic and hadronic calorimeters. The University of Michigan is assembling and implementing a test stand to characterize the dark count rate, temperature dependence, gain, and photon detection efficiency of SiPMs. To more accurately determine the dark count rate, we have constructed a light tight box to isolate the SiPM, which surrounds an electronics enclosure that protects the SiPM circuitry, and installed software to record the output signals. With this system, we will begin to collect data and optimize the system to test arrays of SiPMs instead of single devices as the proposed calorimeters will require testing approximately 115,000 SiPMs.

Fast CsI-phoswich detector

DOEpatents

Langenbrunner, James R.

1996-01-01

An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI.

Fast CsI-phoswich detector

DOEpatents

Langenbrunner, J.R.

1996-05-07

An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI. 5 figs.

HIGH CURRENT COAXIAL PHOTOMULTIPLIER TUBE

DOEpatents

Glass, N.W.

1960-01-19

A medium-gain photomultiplier tube having high current output, fast rise- time, and matched output impedance was developed. The photomultiplier tube comprises an elongated cylindrical envelope, a cylindrical anode supported at the axis of the envelope, a plurality of elongated spaced opaque areas on the envelope, and a plurality of light admitting windows. A photo-cathode is supported adjacent to each of the windows, and a plurality of secondary emissive dynodes are arranged in two types of radial arrays which are alternately positioned to fill the annular space between the anode and the envelope. The dynodes are in an array being radially staggered with respect to the dynodes in the adjacent array, the dynodes each having a portion arranged at an angle with respect to the electron path, such that electrons emitted by each cathode undergo multiplication upon impingement on a dynode and redirected flight to the next adjacent dynode.

Readout architecture for sub-nanosecond resolution TDC

NASA Astrophysics Data System (ADS)

Marteau, J.; Carlus, B.; Gardien, S.; Girerd, C.; Ianigro, J.-C.; Montorio, J.-L.; Gibert, D.; Nicollin, F.

2012-04-01

The DIAPHANE project is pluri-disciplinary collaboration between particle physicists and geophysicists to perform the tomography of large geological structure mainly devoted to the study of active volcanoes. The detector used for this tomography, hereafter referred to as telescope, uses a standard, robust, cost-effective and well-known technology based on solid plastic scintillator readout by photomultiplier(s) (either multichannel pixelized PM or silicon PM). The electronics system is built on the concept of autonomous, triggerless, smart sensor directly connected on a standard fast Ethernet network. First radiographies have been performed on the Mont-Terri underground laboratory (St-Ursanne, Switzerland) and on the active volcano of La Soufrière (Guadeloupe, Lesser Antilles, France). We present an upgrade of the readout architecture allowing to embed a sub-nanosecond resolution TDC within the existing programmable logic to help in the background rejection (rear flux, random coincidences) and to improve the detection purity and the radiography quality. First results obtained are also presented and briefly discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.

The DarkSide-50 experiment at the Laboratori Nazionali del Gran Sasso is a search for dark matter using a dual phase time projection chamber with 50 kg of low radioactivity argon as target. Light signals from interactions in the argon are detected by a system of 38 photo-multiplier tubes (PMTs), 19 above and 19 below the TPC volume inside the argon cryostat. We describe the electronics which processes the signals from the photo-multipliers, the trigger system which identifies events of interest, and the data-acquisition system which records the data for further analysis. The electronics include resistive voltage dividers on the PMTs,more » custom pre-amplifiers mounted directly on the PMT voltage dividers in the liquid argon, and custom amplifier/discriminators (at room temperature). After amplification, the PMT signals are digitized in CAEN waveform digitizers, and CAEN logic modules are used to construct the trigger, the data acquisition system for the TPC is based on the Fermilab "artdaq" software. The system has been in operation since early 2014.« less

The gamma-ray Cherenkov telescope for the Cherenkov telescope array

NASA Astrophysics Data System (ADS)

Tibaldo, L.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kraus, M.; Lapington, J. S.; Laporte, P.; Lefaucheur, J.; Markoff, S.; Melse, T.; Mohrmann, L.; Molyneux, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayède, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Trichard, C.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-01-01

The Cherenkov Telescope Array (CTA) is a forthcoming ground-based observatory for very-high-energy gamma rays. CTA will consist of two arrays of imaging atmospheric Cherenkov telescopes in the Northern and Southern hemispheres, and will combine telescopes of different types to achieve unprecedented performance and energy coverage. The Gamma-ray Cherenkov Telescope (GCT) is one of the small-sized telescopes proposed for CTA to explore the energy range from a few TeV to hundreds of TeV with a field of view ≳ 8° and angular resolution of a few arcminutes. The GCT design features dual-mirror Schwarzschild-Couder optics and a compact camera based on densely-pixelated photodetectors as well as custom electronics. In this contribution we provide an overview of the GCT project with focus on prototype development and testing that is currently ongoing. We present results obtained during the first on-telescope campaign in late 2015 at the Observatoire de Paris-Meudon, during which we recorded the first Cherenkov images from atmospheric showers with the GCT multi-anode photomultiplier camera prototype. We also discuss the development of a second GCT camera prototype with silicon photomultipliers as photosensors, and plans toward a contribution to the realisation of CTA.

A depth-of-interaction PET detector using mutual gain-equalized silicon photomultiplier

DOE Office of Scientific and Technical Information (OSTI.GOV)

W. Xi, A.G, Weisenberger, H. Dong, Brian Kross, S. Lee, J. McKisson, Carl Zorn

We developed a prototype high resolution, high efficiency depth-encoding detector for PET applications based on dual-ended readout of LYSO array with two silicon photomultipliers (SiPMs). Flood images, energy resolution, and depth-of-interaction (DOI) resolution were measured for a LYSO array - 0.7 mm in crystal pitch and 10 mm in thickness - with four unpolished parallel sides. Flood images were obtained such that individual crystal element in the array is resolved. The energy resolution of the entire array was measured to be 33%, while individual crystal pixel elements utilizing the signal from both sides ranged from 23.3% to 27%. By applyingmore » a mutual-gain equalization method, a DOI resolution of 2 mm for the crystal array was obtained in the experiments while simulations indicate {approx}1 mm DOI resolution could possibly be achieved. The experimental DOI resolution can be further improved by obtaining revised detector supporting electronics with better energy resolutions. This study provides a detailed detector calibration and DOI response characterization of the dual-ended readout SiPM-based PET detectors, which will be important in the design and calibration of a PET scanner in the future.« less

SiPM based readout system for PbWO4 crystals

NASA Astrophysics Data System (ADS)

Berra, A.; Bolognini, D.; Bonfanti, S.; Bonvicini, V.; Lietti, D.; Penzo, A.; Prest, M.; Stoppani, L.; Vallazza, E.

2013-08-01

Silicon PhotoMultipliers (SiPMs) consist of a matrix of small passively quenched silicon avalanche photodiodes operated in limited Geiger-mode (GM-APDs) and read out in parallel from a common output node. Each pixel (with a typical size in the 20-100 μm range) gives the same current response when hit by a photon; the SiPM output signal is the sum of the signals of all the pixels, which depends on the light intensity. The main advantages of SiPMs with respect to photomultiplier tubes (PMTs) are essentially the small dimensions, the insensitivity to magnetic fields and a low bias voltage. This contribution presents the performance of a SiPM based readout system for crystal calorimeters developed in the framework of the FACTOR/TWICE collaboration. The SiPM used for the test is a new device produced by FBK-irst which consists in a matrix of four sensors embedded in the same silicon substrate, called QUAD. The SiPM has been coupled to a lead tungstate crystal, an early-prototype version of the crystals developed for the electromagnetic calorimeter of the CMS experiment. New tests are foreseen using a complete module consisting of nine crystals, each one readout by two QUADs.

Scalable gamma-ray camera for wide-area search based on silicon photomultipliers array

NASA Astrophysics Data System (ADS)

Jeong, Manhee; Van, Benjamin; Wells, Byron T.; D'Aries, Lawrence J.; Hammig, Mark D.

2018-03-01

Portable coded-aperture imaging systems based on scintillators and semiconductors have found use in a variety of radiological applications. For stand-off detection of weakly emitting materials, large volume detectors can facilitate the rapid localization of emitting materials. We describe a scalable coded-aperture imaging system based on 5.02 × 5.02 cm2 CsI(Tl) scintillator modules, each partitioned into 4 × 4 × 20 mm3 pixels that are optically coupled to 12 × 12 pixel silicon photo-multiplier (SiPM) arrays. The 144 pixels per module are read-out with a resistor-based charge-division circuit that reduces the readout outputs from 144 to four signals per module, from which the interaction position and total deposited energy can be extracted. All 144 CsI(Tl) pixels are readily distinguishable with an average energy resolution, at 662 keV, of 13.7% FWHM, a peak-to-valley ratio of 8.2, and a peak-to-Compton ratio of 2.9. The detector module is composed of a SiPM array coupled with a 2 cm thick scintillator and modified uniformly redundant array mask. For the image reconstruction, cross correlation and maximum likelihood expectation maximization methods are used. The system shows a field of view of 45° and an angular resolution of 4.7° FWHM.

Position measurements for heavy ion beams using a sodium iodide scintillator

NASA Technical Reports Server (NTRS)

Buffington, A.; Lau, K.; Schindler, S. M.

1981-01-01

A 50 cm diameter, 1.7 cm thick disc of NaI scintillator has been mounted to permit edge viewing by four photomultipliers. Energetic heavy ions passing through the scintillator at different positions cause a variation in the division of light among the photomultipliers. A performance close to the expected limit for 670 MeV/n neon has been achieved. Calculations of expected response using an optical model agree well with the measurements.

Position sensitive solid-state photomultipliers, systems and methods

DOEpatents

Shah, Kanai S; Christian, James; Stapels, Christopher; Dokhale, Purushottam; McClish, Mickel

2014-11-11

An integrated silicon solid state photomultiplier (SSPM) device includes a pixel unit including an array of more than 2.times.2 p-n photodiodes on a common substrate, a signal division network electrically connected to each photodiode, where the signal division network includes four output connections, a signal output measurement unit, a processing unit configured to identify the photodiode generating a signal or a center of mass of photodiodes generating a signal, and a global receiving unit.

A voltage to frequency converter for astronomical photometry

NASA Technical Reports Server (NTRS)

Dunham, E.; Elliot, J. L.

1978-01-01

A voltage to frequency converter (VFC) for general use with photomultipliers is described. For high light levels, when the dead-time corrections for a photon counter would be excessive, the VFC maintains a linear response and allows the recording of data at high time resolution. Results of laboratory tests are given for the signal-to-noise characteristics, linearity, stability, and transient response of the VFC when used in conjunction with EMI 9658 and RCA C31034 photomultipliers.

Muon detection studied by pulse-height energy analysis: Novel converter arrangements.

PubMed

Holmlid, Leif; Olafsson, Sveinn

2015-08-01

Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

Muon detection studied by pulse-height energy analysis: Novel converter arrangements

NASA Astrophysics Data System (ADS)

Holmlid, Leif; Olafsson, Sveinn

2015-08-01

Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

Muon detection studied by pulse-height energy analysis: Novel converter arrangements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmlid, Leif, E-mail: holmlid@chem.gu.se; Olafsson, Sveinn

2015-08-15

Muons are conventionally measured by a plastic scintillator–photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shownmore » here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.« less

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

NASA Astrophysics Data System (ADS)

Roy, Anindya; Bhole, R. B.; Nandy, Partha P.; Yadav, R. C.; Pal, Sarbajit; Roy, Amitava

2015-03-01

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata.

PubMed

Roy, Anindya; Bhole, R B; Nandy, Partha P; Yadav, R C; Pal, Sarbajit; Roy, Amitava

2015-03-01

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A set of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.

Development of a composite large-size SiPM (assembled matrix) based modular detector cluster for MAGIC

NASA Astrophysics Data System (ADS)

Hahn, A.; Mazin, D.; Bangale, P.; Dettlaff, A.; Fink, D.; Grundner, F.; Haberer, W.; Maier, R.; Mirzoyan, R.; Podkladkin, S.; Teshima, M.; Wetteskind, H.

2017-02-01

The MAGIC collaboration operates two 17 m diameter Imaging Atmospheric Cherenkov Telescopes (IACTs) on the Canary Island of La Palma. Each of the two telescopes is currently equipped with a photomultiplier tube (PMT) based imaging camera. Due to the advances in the development of Silicon Photomultipliers (SiPMs), they are becoming a widely used alternative to PMTs in many research fields including gamma-ray astronomy. Within the Otto-Hahn group at the Max Planck Institute for Physics, Munich, we are developing a SiPM based detector module for a possible upgrade of the MAGIC cameras and also for future experiments as, e.g., the Large Size Telescopes (LST) of the Cherenkov Telescope Array (CTA). Because of the small size of individual SiPM sensors (6 mm×6 mm) with respect to the 1-inch diameter PMTs currently used in MAGIC, we use a custom-made matrix of SiPMs to cover the same detection area. We developed an electronic circuit to actively sum up and amplify the SiPM signals. Existing non-imaging hexagonal light concentrators (Winston cones) used in MAGIC have been modified for the angular acceptance of the SiPMs by using C++ based ray tracing simulations. The first prototype based detector module includes seven channels and was installed into the MAGIC camera in May 2015. We present the results of the first prototype and its performance as well as the status of the project and discuss its challenges.

JPRS Report, Science & Technology, USSR: Chemistry.

DTIC Science & Technology

1988-07-06

During Hydrodynamic Cavitation [A. V. Yefimov, G.A. Vorobyev; ZHURNAL FIZICHESKOY KHIMII No 1, Jan 88] 7 COMBUSTION AND EXPLOSIVES Suppression of...RSR", 1988 12770 Microhits and Luminescent Flashes During Hydrodynamic Cavitation 18410249b Moscow ZHURNAL FIZICHESKOY KHIMII in Russian Vol 62, No...monitor the occurrence of hydrodynamic cavitation and make an online estimate of its erosion activity by using devices based on photomultiplier tubes

Hydrocarbon-Fueled Scramjet Research at Hypersonic Mach Numbers

DTIC Science & Technology

2005-03-31

oxide O atomic oxygen 02 molecular oxygen OH hydroxyl radical ppm parts per million PD photodiode PLLF planar laser-induced fluorescence PMT...photomultiplier tube RAM random access memory RANS Reynolds-averaged Navier-Stokes RET rotational energy transfer TDLAS tunable diode laser absorption...here extend this knowledge base to flight at Mach 11.5. Griffiths (2004) used a tunable diode laser absorption spectroscopy ( TDLAS ) system to measure

Measurement of the Minority Carrier Diffusion Rate in N-GaAs.

DTIC Science & Technology

1980-12-01

allow insertion of a fiber -optic cable. This fiber -optic link was necessary to permit a reference signal to impinge upon the photo- multiplier for some...lens onto the entrance slit of the spectrometer. The spectrometer is coupled by means of a light-tight coupler to the photomultiplier, and a fiber ...optic light path is provided to allow a reference 2 ’i29 1 "-I Laser Doubler - 1.06 Filters Pellicle Photomultiplier 0Spectrometer Lens/ Fiber RG-715

A method for characterizing after-pulsing and dark noise of PMTs and SiPMs

NASA Astrophysics Data System (ADS)

Butcher, A.; Doria, L.; Monroe, J.; Retière, F.; Smith, B.; Walding, J.

2017-12-01

Photo-multiplier tubes (PMTs) and silicon photo-multipliers (SiPMs) are detectors sensitive to single photons that are widely used for the detection of scintillation and Cerenkov light in subatomic physics and medical imaging. This paper presents a method for characterizing two of the main noise sources that PMTs and SiPMs share: dark noise and correlated noise (after-pulsing). The proposed method allows for a model-independent measurement of the after-pulsing timing distribution and dark noise rate.

Large volume flow-through scintillating detector

DOEpatents

Gritzo, Russ E.; Fowler, Malcolm M.

1995-01-01

A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

Novel MCP-Based Electron Source Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haughey, M.; Shiltsev V., Shiltsev V.; Stancari, G.

Microchannel plates (MCPs) were recently proposed as novel type of cathodes for electron guns [1], suitable for applications in design of electron lenses. We report results of the first systematic study of microchannel plate based photomultiplier time response and maximum cur-rent density tests using different sources of light pulses. The Burle 85011-501 MCP-PMT is found to have good time response properties being capable of producing na-nosecond long pulses with modest maximum current density and performance strongly dependent on magnetic field strength.

A novel post-arc current measuring equipment based on vacuum arc commutation and arc blow

NASA Astrophysics Data System (ADS)

Liao, Minfu; Ge, Guowei; Duan, Xiongying; Huang, Zhihui

2017-07-01

The paper proposes a novel post-arc current measuring equipment (NPACME), which is based on the vacuum arc commutation and magnetic arc blow. The NPACME is composed of the vacuum circuit breaker (VCB), shunt resistor, protective gap, high-precision current sensor and externally applied transverse magnetic field (ETMF). The prototype of the NPACME is designed and controlled by optical fiber communications. The vacuum arc commutation between the vacuum arc and the shunt resistor with ETMF is investigated. The test platform is established in the synthetic short-circuit test and the vacuum arc is observed by the high speed CMOS camera. The mathematic description of the vacuum arc commutation is obtained. Based on the current commutation characteristic, the parameters of the NPACME are optimized and the post-arc current is measured. The measuring result of the post-arc current is accurate with small interference and the post-arc charge is obtained. The experimental results verify that the NPACME is correct and accurate, which can be used to measure the post-arc characteristic in breaking test.

Performance of CATIROC: ASIC for smart readout of large photomultiplier arrays

NASA Astrophysics Data System (ADS)

Blin, S.; Callier, S.; Conforti Di Lorenzo, S.; Dulucq, F.; De La Taille, C.; Martin-Chassard, G.; Seguin-Moreau, N.

2017-03-01

CATIROC (Charge And Time Integrated Read Out Chip) is a complete read-out chip manufactured in AustriaMicroSystem (AMS) SiGe 0.35 μm technology, designed to read arrays of 16 photomultipliers (PMTs). It is an upgraded version of PARISROC2 [1] designed in 2010 in the context of the PMm2 (square meter PhotoMultiplier) project [2]. CATIROC is a SoC (System on Chip) that processes analog signals up to the digitization and sparsification to reduce the cost and cable number. The ASIC is composed of 16 independent channels that work in triggerless mode, auto-triggering on the single photo-electron. It provides a charge measurement up to 400 photoelectrons (70 pC) on two scales of 10 bits and a timing information with an accuracy of 200 ps rms. The ASIC was sent for fabrication in February 2015 and then received in September 2015. It is a good candidate for two Chinese projects (LHAASO and JUNO). The architecture and the measurements will be detailed in the paper.

Precision analysis of the photomultiplier response to ultra low signals

NASA Astrophysics Data System (ADS)

Degtiarenko, Pavel

2017-11-01

A new computational model for the description of the photon detector response functions measured in conditions of low light is presented, together with examples of the observed photomultiplier signal amplitude distributions, successfully described using the parameterized model equation. In extension to the previously known approximations, the new model describes the underlying discrete statistical behavior of the photoelectron cascade multiplication processes in photon detectors with complex non-uniform gain structure of the first dynode. Important features of the model include the ability to represent the true single-photoelectron spectra from different photomultipliers with a variety of parameterized shapes, reflecting the variability in the design and in the individual parameters of the detectors. The new software tool is available for evaluation of the detectors' performance, response, and efficiency parameters that may be used in various applications including the ultra low background experiments such as the searches for Dark Matter and rare decays, underground neutrino studies, optimizing operations of the Cherenkov light detectors, help in the detector selection procedures, and in the experiment simulations.

Review of 72.5kV double-break vacuum circuit breaker based on rapid repulsion actuator

NASA Astrophysics Data System (ADS)

Zhuofan, Tang; Lijun, Qin

2017-07-01

72.5kV double-break vacuum circuit breakers based on rapid repulsion actuator remain blank in China. Based on the theoretical analysis and experimental results from researchers, the design of 72.5kV double-break vacuum circuit breakers based on rapid repulsion actuator was presented. It takes the form of double-break, using two standard 40.5kV vacuum interrupter in series at the bottom, which adopt a permanent magnetic repulsion actuator. The permanent magnetic repulsion actuator consists of rapid repulsion actuator and magnetic retentivity actuator. On the basis above, we produced the prototype, and the superiority of the design was verified through the experiments.

Implementation of EPICS based vacuum control system for variable energy cyclotron centre, Kolkata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Anindya, E-mail: r-ani@vecc.gov.in; Bhole, R. B.; Nandy, Partha P.

2015-03-15

The vacuum system of the Room Temperature (K = 130) Cyclotron of Variable Energy Cyclotron Centre is comprised of vacuum systems of main machine and Beam Transport System. The vacuum control system is upgraded to a PLC based Automated system from the initial relay based Manual system. The supervisory control of the vacuum system is implemented in Experimental Physics and Industrial Control System (EPICS). An EPICS embedded ARM based vacuum gauge controller is developed to mitigate the requirement of vendor specific gauge controller for gauges and also for seamless integration of the gauge controllers with the control system. A setmore » of MS-Windows ActiveX components with embedded EPICS Channel Access interface are developed to build operator interfaces with less complex programming and to incorporate typical Windows feature, e.g., user authentication, file handling, better fonts, colors, mouse actions etc. into the operator interfaces. The control parameters, monitoring parameters, and system interlocks of the system are archived in MySQL based EPICS MySQL Archiver developed indigenously. In this paper, we describe the architecture, the implementation details, and the performance of the system.« less

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

NASA Astrophysics Data System (ADS)

Aspinall, Michael D.; Jones, Ashley R.

2018-01-01

Systems that adopt organic scintillation detector arrays often require a calibration process prior to the intended measurement campaign to correct for significant performance variances between detectors within the array. These differences exist because of low tolerances associated with photo-multiplier tube technology and environmental influences. Differences in detector response can be corrected for by adjusting the supplied photo-multiplier tube voltage to control its gain and the effect that this has on the pulse height spectra from a gamma-only calibration source with a defined photo-peak. Automated methods that analyze these spectra and adjust the photo-multiplier tube bias accordingly are emerging for hardware that integrate acquisition electronics and high voltage control. However, development of such algorithms require access to the hardware, multiple detectors and calibration source for prolonged periods, all with associated constraints and risks. In this work, we report on a software function and related models developed to rescale and regenerate pulse height data acquired from a single scintillation detector. Such a function could be used to generate significant and varied pulse height data that can be used to integration-test algorithms that are capable of automatically response matching multiple detectors using pulse height spectra analysis. Furthermore, a function of this sort removes the dependence on multiple detectors, digital analyzers and calibration source. Results show a good match between the real and regenerated pulse height data. The function has also been used successfully to develop auto-calibration algorithms.

Vacuum Levels Needed to Simulate Internal Fatigue Crack Growth in Titanium Alloys and Nickel-Base Superalloys Thermaodynamic Conditioners (Preprint)

DTIC Science & Technology

2012-08-01

AFRL-RX-WP-TP-2012-0412 VACUUM LEVELS NEEDED TO SIMULATE INTERNAL FATIGUE CRACK GROWTH IN TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS...LEVELS NEEDED TO SIMULATE INTERNAL FATIGUE CRACK GROWTH IN TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS: THERMAODYNAMIC CONSIDERATIONS (PREPRINT) 5a...have examined fatigue growth of surface cracks in vacuum to simulate sub-surface growth in Ti- alloys and Ni - base superalloys. Even with the highest

Evaluation of Vacuum Blasting and Heat Guns as Methods for Abating Lead- Based Paint on Buildings

DTIC Science & Technology

1993-09-01

INCOMPATIBILITY - Contact with powerful oxidizing agents such as FLUORINE, CHLORINE TRIFLUORIDE , MANGANESE TRIOXIDE, OXYGEN DIFLUORIDE, MANGANESE...investigating new technologies for lead-based paint abatement. This research evaluates the effectiveness , safety, LEC1L•.T• and cost of vacuum abrasive...paint abatement. This research evaluates the effectiveness , safety, and cost of vacuum abrasive units and heat guns as methods of removing lead-based

Cryogenic Laboratory Experiments into Radiation Effects on the Spectra of Non-Ice Materials relevant to Ocean Worlds

NASA Astrophysics Data System (ADS)

Cahill, K. R. S.; Hibbitts, C.; Wing, B. R.

2017-12-01

The airless satellites of Jupiter and Saturn are bombarded by high-energy particles from solar wind and their planetary magnetospheres. The particles range up to MeV energies and penetrate sufficiently far (microns) into the surface to cause damage that can affect their UV - IR spectral signatures. These particles physically and chemically alter the exposed surface by damaging crystallinity, sputtering non-refractory neutrals, depositing into the material, and inducing chemical reactions between existing and/or exogenous components. Previous studies of salts irradiated at room temperature ( 293 K) under high vacuum (1e-7 Torr) demonstrated the formation of radiation-induced color centers, or Farbe-centers, that are active at near UV, visible, and near IR wavelengths [1,2]. In this study, we investigated the effects of irradiation on these and other materials at temperatures relevant to the surfaces of the Galilean and Saturnian satellites. Experiments at the appropriate temperatures are important because the diffusion of the H-centers, which can interact with F-centers [3], are strongly temperature dependent and may be inhibited. This could affect the spectral signature of the irradiated materials. The experiments simulated the radiation environment using 40 keV electrons at 80 microamps under high vacuum at 100 K while characterizing the spectral changes (UV through mid-IR). Spectral measurements were obtained in the UV-Visible ( 130-570 nm) using a McPherson monochromater and photomultiplier detector, in the Visible-SWIR ( 340-2500 nm) using a SVC point spectrometer, and in the NIR-MIR ( 1500 to 8000 nm) using a Bruker Vertex 70 FTIR coupled to a liquid nitrogen cooled MCT detector. Spectra were collected while the sample was held under high vacuum at cryogenic temperatures both before, during, and after irradiation. Our results characterize the spectral signature of radiation-induced color centers that can form at the temperatures present at the surface of airless ocean worlds. We will show the spectral change induced by irradiation at cryogenic temperatures and compare these results to performed at room temperature. [1] Hibbitts et al. [2017], Icarus, submitted. [2] Hand and Carlson. [2015], GRL, 42, 3174-3178. [3] Soppe et al. [1994] J. Nuc. Mat., 217, 1-31.

Pulse shape discrimination based on fast signals from silicon photomultipliers

NASA Astrophysics Data System (ADS)

Yu, Junhao; Wei, Zhiyong; Fang, Meihua; Zhang, Zixia; Cheng, Can; Wang, Yi; Su, Huiwen; Ran, Youquan; Zhu, Qingwei; Zhang, He; Duan, Kai; Chen, Ming; Liu, Meng

2018-06-01

Recent developments in organic plastic scintillators capable of pulse shape discrimination (PSD) enable a breakthrough in discrimination between neutrons and gammas. Plastic scintillator detectors coupled with silicon photomultipliers (SiPMs) offer many advantages, such as lower power consumption, smaller volume, and especially insensitivity to magnetic fields, compared with conventional photomultiplier tubes (PMTs). A SensL SiPM has two outputs: a standard output and a fast output. It is known that the charge injected into the fast output electrode is typically approximately 2% of the total charge generated during the avalanche, whereas the charge injected into the standard output electrode is nearly 98% of the total. Fast signals from SiPMs exhibit better performance in terms of timing and time-correlated measurements compared with standard signals. The pulse duration of a standard signal is on the order of hundreds of nanoseconds, whereas the pulse duration of the main monopole waveform of a fast signal is a few tens of nanoseconds. Fast signals are traditionally thought to be suitable for photon counting at very high speeds but unsuitable for PSD due to the partial charge collection. Meanwhile, the standard outputs of SiPMs coupled with discriminating scintillators have yielded nice PSD performances, but there have been no reports on PSD using fast signals. Our analysis shows that fast signals can also provide discrimination if the rate of charge injection into the fast output electrode is fixed for each event, even though only a portion of the charge is collected. In this work, we achieved successful PSD using fast signals; meanwhile, using a coincidence timing window of less 3 nanoseconds between the readouts from both ends of the detector reduced the influence of the high SiPM dark current. We experimentally achieved good timing performance and PSD capability simultaneously.

Systems and Methods for Fabricating Carbon Nanotube-Based Vacuum Electronic Devices

NASA Technical Reports Server (NTRS)

Manohara, Harish (Inventor); Toda, Risaku (Inventor); Del Castillo, Linda Y. (Inventor); Murthy, Rakesh (Inventor)

2015-01-01

Systems and methods in accordance with embodiments of the invention proficiently produce carbon nanotube-based vacuum electronic devices. In one embodiment a method of fabricating a carbon nanotube-based vacuum electronic device includes: growing carbon nanotubes onto a substrate to form a cathode; assembling a stack that includes the cathode, an anode, and a first layer that includes an alignment slot; disposing a microsphere partially into the alignment slot during the assembling of the stack such that the microsphere protrudes from the alignment slot and can thereby separate the first layer from an adjacent layer; and encasing the stack in a vacuum sealed container.

Diagnosing Recent Failures In Hodoscope Photomultiplier Tube Bases For FNAL E906

NASA Astrophysics Data System (ADS)

Stien, Haley; SeaQuest Collaboration

2017-09-01

The E906/SeaQuest experiment at Fermi National Accelerator Laboratory is researching the nucleon quark sea in order to provide an accurate determination of the quark and anti-quark distributions within the nucleon. By colliding a 120 GeV proton beam with a set of fixed targets and tracking the dimuons that hit the detectors, it is possible to study the quark/anti-quark interaction that produced the unique dimuon through the Drell-Yan process. However, E906 recently began to experience a number of failures in the Hodoscope Photomultiplier Tube bases in the first two detector stations, which are used in the trigger. It was known that the two most likely causes were radiation damage or overheating. Radiation damage was able to be ruled out when it was found that there was no increase in the number of base failures in high rate areas. It was clear that the heat generated on the custom high rate bases caused several components on the daughter cards to slowly overheat until failure. Using thermal imaging and two temperature probes, it was observed that the components on the daughter cards would reach temperatures over 100 degrees Celcius very quickly during our tests. This presentation will discuss the diagnostic process and summarize how this issue will be prevented in the future. Supported by U.S. D.O.E. Medium Energy Nuclear Physics under Grant DE-FG02-03ER41243.

Photodetection Characterization of SiPM Technologies for their Application in Scintillator based Neutron Detectors

NASA Astrophysics Data System (ADS)

Kumar, S.; Durini, D.; Degenhardt, C.; van Waasen, S.

2018-01-01

Small-angle neutron scattering (SANS) experiments have become one of the most important techniques in the investigation of the properties of material on the atomic scale. Until 2001, nearly exclusively 3He-based detectors were used for neutron detection in these experiments, but due to the scarcity of 3He and its steeply rising price, researchers started to look for suitable alternatives. Scintillation based solid state detectors appeared as a prominent alternative. Silicon photomultipliers (SiPM), having single photon resolution, lower bias voltages compared to photomultiplier tubes (PMT), insensitivity to magnetic fields, low cost, possibility of modular design and higher readout rates, have the potential of becoming a photon detector of choice in scintillator based neutron detectors. The major concerns for utilizing the SiPM technology in this kind of applications are the increase in their noise performance and the decrease in their photon detection efficiency (PDE) due to direct exposure to neutrons. Here, a detailed comparative analysis of the PDE performance in the range between UV and NIR parts of the spectra for three different SiPM technologies, before and after irradiation with cold neutrons, has been carried out. For this investigation, one digital and two analog SiPM arrays were irradiated with 5Å wavelength cold neutrons and up to a dose of 6×1012 n/cm2 at the KWS-1 instrument of the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany.

Photodetectors for Nuclear Medical Imaging

PubMed Central

Moses, William W.

2009-01-01

There have been a number of recent advances in photodetector technology, notably in photomultiplier tubes with high quantum efficiency (up to ~50%), hybrid photodetectors, and silicon-based Geiger-mode photodetectors. This paper looks at the potential benefits that these technologies can bring to nuclear medicine, notably SPECT and PET. We find that while the potential benefits to SPECT are relatively small, they can bring performance improvements in many areas for PET. PMID:20161403

The photomultiplier tube calibration system of the MicroBooNE experiment

DOE PAGES

Conrad, J.; Jones, B. J. P.; Moss, Z.; ...

2015-06-03

Here, we report on the design and construction of a LED-based fiber calibration system for large liquid argon time projection detectors. This system was developed to calibrate the optical systems of the MicroBooNE experiment. As well as detailing the materials and installation procedure, we provide technical drawings and specifications so that the system may be easily replicated in future LArTPC detectors.

Charge reconstruction in large-area photomultipliers

NASA Astrophysics Data System (ADS)

Grassi, M.; Montuschi, M.; Baldoncini, M.; Mantovani, F.; Ricci, B.; Andronico, G.; Antonelli, V.; Bellato, M.; Bernieri, E.; Brigatti, A.; Brugnera, R.; Budano, A.; Buscemi, M.; Bussino, S.; Caruso, R.; Chiesa, D.; Corti, D.; Dal Corso, F.; Ding, X. F.; Dusini, S.; Fabbri, A.; Fiorentini, G.; Ford, R.; Formozov, A.; Galet, G.; Garfagnini, A.; Giammarchi, M.; Giaz, A.; Insolia, A.; Isocrate, R.; Lippi, I.; Longhitano, F.; Lo Presti, D.; Lombardi, P.; Marini, F.; Mari, S. M.; Martellini, C.; Meroni, E.; Mezzetto, M.; Miramonti, L.; Monforte, S.; Nastasi, M.; Ortica, F.; Paoloni, A.; Parmeggiano, S.; Pedretti, D.; Pelliccia, N.; Pompilio, R.; Previtali, E.; Ranucci, G.; Re, A. C.; Romani, A.; Saggese, P.; Salamanna, G.; Sawy, F. H.; Settanta, G.; Sisti, M.; Sirignano, C.; Spinetti, M.; Stanco, L.; Strati, V.; Verde, G.; Votano, L.

2018-02-01

Large-area PhotoMultiplier Tubes (PMT) allow to efficiently instrument Liquid Scintillator (LS) neutrino detectors, where large target masses are pivotal to compensate for neutrinos' extremely elusive nature. Depending on the detector light yield, several scintillation photons stemming from the same neutrino interaction are likely to hit a single PMT in a few tens/hundreds of nanoseconds, resulting in several photoelectrons (PEs) to pile-up at the PMT anode. In such scenario, the signal generated by each PE is entangled to the others, and an accurate PMT charge reconstruction becomes challenging. This manuscript describes an experimental method able to address the PMT charge reconstruction in the case of large PE pile-up, providing an unbiased charge estimator at the permille level up to 15 detected PEs. The method is based on a signal filtering technique (Wiener filter) which suppresses the noise due to both PMT and readout electronics, and on a Fourier-based deconvolution able to minimize the influence of signal distortions—such as an overshoot. The analysis of simulated PMT waveforms shows that the slope of a linear regression modeling the relation between reconstructed and true charge values improves from 0.769 ± 0.001 (without deconvolution) to 0.989 ± 0.001 (with deconvolution), where unitary slope implies perfect reconstruction. A C++ implementation of the charge reconstruction algorithm is available online at [1].

Application of TDCR-Geant4 modeling to standardization of 63Ni.

PubMed

Thiam, C; Bobin, C; Chauvenet, B; Bouchard, J

2012-09-01

As an alternative to the classical TDCR model applied to liquid scintillation (LS) counting, a stochastic approach based on the Geant4 toolkit is presented for the simulation of light emission inside the dedicated three-photomultiplier detection system. To this end, the Geant4 modeling includes a comprehensive description of optical properties associated with each material constituting the optical chamber. The objective is to simulate the propagation of optical photons from their creation in the LS cocktail to the production of photoelectrons in the photomultipliers. First validated for the case of radionuclide standardization based on Cerenkov emission, the scintillation process has been added to a TDCR-Geant4 modeling using the Birks expression in order to account for the light-emission nonlinearity owing to ionization quenching. The scintillation yield of the commercial Ultima Gold LS cocktail has been determined from double-coincidence detection efficiencies obtained for (60)Co and (54)Mn with the 4π(LS)β-γ coincidence method. In this paper, the stochastic TDCR modeling is applied for the case of the standardization of (63)Ni (pure β(-)-emitter; E(max)=66.98 keV) and the activity concentration is compared with the result given by the classical model. Copyright © 2012 Elsevier Ltd. All rights reserved.

A wearable sensor based on CLYC scintillators

NASA Astrophysics Data System (ADS)

McDonald, Benjamin S.; Myjak, Mitchell J.; Zalavadia, Mital A.; Smart, John E.; Willett, Jesse A.; Landgren, Peter C.; Greulich, Christopher R.

2016-06-01

We have developed a wearable radiation sensor using Cs2LiYCl6:Ce (CLYC) for simultaneous gamma-ray and neutron detection. The system includes two ∅ 2.5 × 2.5cm3 crystals coupled to small, metal-body photomultiplier tubes. A custom, low-power electronics base digitizes the output signal at three time points and enables both pulse height and pulse shape discrimination of gamma rays and neutrons. The total counts, anomaly detection metrics, and identified isotopes are displayed on a small screen. Users may leave the device in unattended mode to collect long-dwell energy spectra. The system stores up to 18 h of one-second data, including energy spectra, and may transfer the data to a remote computer via a wired or wireless connection. The prototype is 18 × 13 × 7.5cm3, weighs 1.3 kg, not including the protective pouch, and runs on six AA alkaline batteries for 29 h with the wireless link active, or 41 h with the wireless link disabled. In this paper, we summarize the system design and present characterization results from the detector modules. The energy resolution is about 6.5% full width at half maximum at 662 keV due to the small photomultiplier tube selected, and the linearity and pulse shape discrimination performance are very good.

Development and characterization of a round hand-held silicon photomultiplier based gamma camera for intraoperative imaging

PubMed Central

Popovic, Kosta; McKisson, Jack E.; Kross, Brian; Lee, Seungjoon; McKisson, John; Weisenberger, Andrew G.; Proffitt, James; Stolin, Alexander; Majewski, Stan; Williams, Mark B.

2017-01-01

This paper describes the development of a hand-held gamma camera for intraoperative surgical guidance that is based on silicon photomultiplier (SiPM) technology. The camera incorporates a cerium doped lanthanum bromide (LaBr3:Ce) plate scintillator, an array of 80 SiPM photodetectors and a two-layer parallel-hole collimator. The field of view is circular with a 60 mm diameter. The disk-shaped camera housing is 75 mm in diameter, approximately 40.5 mm thick and has a mass of only 1.4 kg, permitting either hand-held or arm-mounted use. All camera components are integrated on a mobile cart that allows easy transport. The camera was developed for use in surgical procedures including determination of the location and extent of primary carcinomas, detection of secondary lesions and sentinel lymph node biopsy (SLNB). Here we describe the camera design and its principal operating characteristics, including spatial resolution, energy resolution, sensitivity uniformity, and geometric linearity. The gamma camera has an intrinsic spatial resolution of 4.2 mm FWHM, an energy resolution of 21.1 % FWHM at 140 keV, and a sensitivity of 481 and 73 cps/MBq when using the single- and double-layer collimators, respectively. PMID:28286345

Simple luminescence detectors using a light-emitting diode or a Xe lamp, optical fiber and charge-coupled device, or photomultiplier for determining proteins in capillary electrophoresis: a critical comparison.

PubMed

Casado-Terrones, Silvia; Fernández-Sánchez, Jorge F; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2007-06-01

The performance of two homemade fluorescence-induced capillary electrophoresis detectors, one based on light-emitting diode (LED) as the excitation source and a charge-coupled device (CCD) photodetector and the other based on a commercial luminescence spectrometer (Xe lamp) as the excitation source and a photomultiplier tube as a detector, were compared for the determination of fluorescent proteins R-phycoerythrin and B-phycoerythrin. Both devices use commercially available, reasonably priced optical components that can be used by nonexperts. After fine optimization of several optical and separation parameters in both devices, a zone capillary electrophoresis methodology was achieved with 50mM borate buffer (pH 8.4) and 10mM phytic acid for the determination of two phycobiliproteins. Detection limits of 0.50 and 0.64microg/ml for R-phycoerythrin and B-phycoerythrin, respectively, were achieved by using the LED-induced fluorescence capillary electrophoresis (LED-IF-CE) system, and corresponding detection limits of 2.73 and 2.16microg/ml were achieved by using the Xe lamp-IF-CE system. Analytical performance and other parameters, such as cost and potential to miniaturization, are compared for both devices.

A wearable sensor based on CLYC scintillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Benjamin S.; Myjak, Mitchell J.; Zalavadia, Mital A.

We developed a wearable radiation sensor using Cs 2LiYCl 6:Ce (CLYC) for simultaneous gamma-ray and neutron detection. The system includes two ø2.5×2.5 cm 3 crystals coupled to small, metal-body photomultiplier tubes. A custom, low-power electronics base digitizes the output signal at three time points and enables both pulse height and pulse shape discrimination of neutrons and gamma-rays. Data, including spectra, can be transferred via a wired or wireless connection. The total gamma-ray and neutron counts, anomaly detection metrics, and identified isotopes are displayed on a small screen on the device. Users may leave the system in unattended mode to collectmore » long-dwell energy spectra. The prototype system has overall dimensions of 13×7.5×18 cm 3 and weight of 1.3 kg, not including the protective pouch, and runs on six AA alkaline batteries for 29 hours with a 1% wireless transmission duty cycle and 41 hours with the wireless turned off . In this paper, we summarize the system design and present characterization results from the detector modules. The energy resolution is about 6.5% full width at half maximum at 662 keV due to the small photomultiplier tube selected, and the linearity and pulse shape discrimination performance are very good.« less

Vacuum Levels Needed to Simulate Internal Fatigue Crack Growth in Titanium Alloys and Nickel-base Superalloys: Thermodynamic Considerations

DTIC Science & Technology

2012-03-01

AFRL-RX-WP-TP-2012-0250 VACUUM LEVELS NEEDED TO SIMULATE INTERNAL FATIGUE CRACK GROWTH IN TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS...TITANIUM ALLOYS AND NICKEL - BASE SUPERALLOYS: THERMODYNAMIC CONSIDERATIONS (PREPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM...surface growth in Ti- alloys and Ni - base superalloys. Even with the highest vacuum level attained using “state-of-the-art” pumps, it is unclear if

Solid-State Photomultiplier with Integrated Front End Electronics

NASA Astrophysics Data System (ADS)

Christian, James; Stapels, Christopher; Johnson, Erik; Mukhopadhyay, Sharmistha; Jie Chen, Xiao; Miskimen, Rory

2009-10-01

The instrumentation cost of physics experiments has been reduced per channel, by the use of solid-state detectors, but these cost-effective techniques have not been translated to scintillation-based detectors. When considering photodetectors, the cost per channel is determined by the use of high-voltage, analog-to-digital converters, BNC cables, and any other ancillary devices. The overhead associated with device operation limits the number of channels for the detector system, while potentially limiting the scope of physics that can be explored. The PRIMEX experiment at JLab, which is being designed to measure the radiative widths of the η and η' pseudo-scalar mesons for a more comprehensive understanding of QCD at low energies, is an example where CMOS solid-state photomultipliers (SSPMs) can be implemented. The ubiquitous nature of CMOS allows for on-chip signal processing to provide front-end electronics within the detector package. We present the results of the device development for the PRIMEX calorimeter, discussing the characteristics of SSPMs, the potential cost savings, and experimental results of on-chip signal processing.

The electronics, trigger and data acquisition system for the liquid argon time projection chamber of the DarkSide-50 search for dark matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.

The DarkSide-50 experiment at the Laboratori Nazionali del Gran Sasso is a search for dark matter using a dual phase time projection chamber with 50 kg of low radioactivity argon as target. Light signals from interactions in the argon are detected by a system of 38 photo-multiplier tubes (PMTs), 19 above and 19 below the TPC volume inside the argon cryostat. We describe the electronics which processes the signals from the photo-multipliers, the trigger system which identifies events of interest, and the data-acquisition system which records the data for further analysis. The electronics include resistive voltage dividers on the PMTs,more » custom pre-amplifiers mounted directly on the PMT voltage dividers in the liquid argon, and custom amplifier/discriminators (at room temperature). After amplification, the PMT signals are digitized in CAEN waveform digitizers, and CAEN logic modules are used to construct the trigger, the data acquisition system for the TPC is based on the Fermilab "artdaq" software. The system has been in operation since early 2014.« less

Temperature behavior of CLYC/MPPC detectors

NASA Astrophysics Data System (ADS)

Glodo, Jarek; McClish, Mickel; Hawrami, Rastgo; O'Dougherty, Patrick; Tower, Josh; Gueorguiev, Andrey; Shah, Kanai S.

2013-09-01

He-3 tubes are the most popular thermal neutron detectors. They are easy to use, have good sensitivity for neutron detection, and are insensitive to gamma radiation. Due to low stockpiles of the He-3 gas, alternatives are being sought to replace these devices in many applications. One of the possible alternatives to these devices are scintillators incorporating isotopes with high cross-section for neutron capture (e.g. Li-6 or B-10). Cs2LiYCl6:Ce (CLYC) is one of the scintillators that recently has been considered for neutron detection. This material offers good detection efficiency (~80%), bright response (70,000 photons/neutron), high gamma ray equivalent energy of the neutron signal (>3MeV), and excellent separation between gamma and neutron radiation with pulse shape discrimination. A He-3 tube alternative based on a CLYC scintillator was constructed using a silicon photomultiplier (SiPM) for the optical readout. SiPMs are very compact optical detectors that are an alternative to usually bulky photomultiplier tubes. Constructed detector was characterized for its behavior across a temperature range of -20°C to 50°C.

The electronics, trigger and data acquisition system for the liquid argon time projection chamber of the DarkSide-50 search for dark matter

NASA Astrophysics Data System (ADS)

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Arisaka, K.; Asner, D. M.; Ave, M.; Back, H. O.; Baldin, B.; Biery, K.; Bocci, V.; Bonfini, G.; Bonivento, W.; Bossa, M.; Bottino, B.; Brigatti, A.; Brodsky, J.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Cao, H.; Caravati, M.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cataudella, V.; Cavalcante, P.; Chepurnov, A.; Cicaló, C.; Cocco, A. G.; Covone, G.; Crippa, L.; D'Angelo, D.; D'Incecco, M.; Davini, S.; de Candia, A.; De Cecco, S.; De Deo, M.; De Filippis, G.; De Rosa, G.; De Vincenzi, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Dionisi, C.; Di Pietro, G.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Forster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Giagu, S.; Giganti, C.; Giovanetti, G. K.; Goretti, A. M.; Granato, F.; Grandi, L.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K. R.; Hughes, D.; Humble, P.; Hungerford, E. V.; Ianni, A.; Ianni, A.; James, I.; Johnson, T. N.; Keeter, K.; Kendziora, C. L.; Kobychev, V.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Loer, B.; Lombardi, P.; Longo, G.; Luitz, S.; Ma, Y.; Machado, A.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Marini, L.; Martoff, C. J.; Meyers, P. D.; Miletic, T.; Milincic, R.; Montanari, D.; Monte, A.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B. J.; Muratova, V. N.; Musico, P.; Navrer Agasson, A.; Nelson, A.; Odrowski, S.; Oleinik, A.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Pelczar, K.; Pelliccia, N.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Ranucci, G.; Razeti, M.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Rescigno, M.; Riffard, Q.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Sablone, D.; Saggese, P.; Saldanha, R.; Sands, W.; Sangiorgio, S.; Savarese, C.; Schlitzer, B.; Segreto, E.; Semenov, D. A.; Shields, E.; Singh, P. N.; Skorokhvatov, M. D.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Verducci, M.; Vishneva, A.; Vogelaar, R. B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Westerdale, S.; Wojcik, M. M.; Xiang, X.; Xiao, X.; Xu, J.; Yang, C.; Yoo, J.; Zavatarelli, S.; Zec, A.; Zhong, W.; Zhu, C.; Zuzel, G.

2017-12-01

The DarkSide-50 experiment at the Laboratori Nazionali del Gran Sasso is a search for dark matter using a dual phase time projection chamber with 50 kg of low radioactivity argon as target. Light signals from interactions in the argon are detected by a system of 38 photo-multiplier tubes (PMTs), 19 above and 19 below the TPC volume inside the argon cryostat. We describe the electronics which processes the signals from the photo-multipliers, the trigger system which identifies events of interest, and the data-acquisition system which records the data for further analysis. The electronics include resistive voltage dividers on the PMTs, custom pre-amplifiers mounted directly on the PMT voltage dividers in the liquid argon, and custom amplifier/discriminators (at room temperature). After amplification, the PMT signals are digitized in CAEN waveform digitizers, and CAEN logic modules are used to construct the trigger; the data acquisition system for the TPC is based on the Fermilab artdaq software. The system has been in operation since early 2014.

The electronics, trigger and data acquisition system for the liquid argon time projection chamber of the DarkSide-50 search for dark matter

DOE PAGES

Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; ...

2017-12-01

The DarkSide-50 experiment at the Laboratori Nazionali del Gran Sasso is a search for dark matter using a dual phase time projection chamber with 50 kg of low radioactivity argon as target. Light signals from interactions in the argon are detected by a system of 38 photo-multiplier tubes (PMTs), 19 above and 19 below the TPC volume inside the argon cryostat. We describe the electronics which processes the signals from the photo-multipliers, the trigger system which identifies events of interest, and the data-acquisition system which records the data for further analysis. The electronics include resistive voltage dividers on the PMTs,more » custom pre-amplifiers mounted directly on the PMT voltage dividers in the liquid argon, and custom amplifier/discriminators (at room temperature). After amplification, the PMT signals are digitized in CAEN waveform digitizers, and CAEN logic modules are used to construct the trigger, the data acquisition system for the TPC is based on the Fermilab "artdaq" software. The system has been in operation since early 2014.« less

Design and performance of vacuum system for high heat flux test facility

NASA Astrophysics Data System (ADS)

Swamy Kidambi, Rajamannar; Mokaria, Prakash; Khirwadkar, Samir; Belsare, Sunil; Khan, M. S.; Patel, Tushar; Krishnan, Deepu S.

2017-04-01

High heat flux test facility (HHFTF) at IPR is used for testing thermal performance of plasma facing materials or components. It consists of various subsystems like vacuum system, high power electron beam system, diagnostic and calibration system, data acquisition and control system and high pressure high temperature water circulation system. Vacuum system consists of large D-shaped chamber, target handling system, pumping systems and support structure. The net volume of vacuum chamber is 5 m3 was maintained at the base pressure of the order of 10-6 mbar for operation of electron gun with minimum beam diameter which is achieved with turbo-molecular pump (TMP) and cryo pump. A variable conductance gate valve is used for maintaining required vacuum in the chamber. Initial pumping of the chamber was carried out by using suitable rotary and root pumps. PXI and PLC based faster real time data acquisition and control system is implemented for performing the various operations like remote operation, online vacuum data measurements, display and status indication of all vacuum equipments. This paper describes in detail the design and implementation of various vacuum system for HHFTF.

Photoelectron yields of scintillation counters with embedded wavelength-shifting fibers read out with silicon photomultipliers

NASA Astrophysics Data System (ADS)

Artikov, Akram; Baranov, Vladimir; Blazey, Gerald C.; Chen, Ningshun; Chokheli, Davit; Davydov, Yuri; Dukes, E. Craig; Dychkant, Alexsander; Ehrlich, Ralf; Francis, Kurt; Frank, M. J.; Glagolev, Vladimir; Group, Craig; Hansen, Sten; Magill, Stephen; Oksuzian, Yuri; Pla-Dalmau, Anna; Rubinov, Paul; Simonenko, Aleksandr; Song, Enhao; Stetzler, Steven; Wu, Yongyi; Uzunyan, Sergey; Zutshi, Vishnu

2018-05-01

Photoelectron yields of extruded scintillation counters with titanium dioxide coating and embedded wavelength shifting fibers read out by silicon photomultipliers have been measured at the Fermilab Test Beam Facility using 120 GeV protons. The yields were measured as a function of transverse, longitudinal, and angular positions for a variety of scintillator compositions, reflective coating mixtures, and fiber diameters. Timing performance was also studied. These studies were carried out by the Cosmic Ray Veto Group of the Mu2e collaboration as part of their R&D program.

Bucking coil implementation on PMT for active canceling of magnetic field

NASA Astrophysics Data System (ADS)

Gogami, T.; Asaturyan, A.; Bono, J.; Baturin, P.; Chen, C.; Chiba, A.; Chiga, N.; Fujii, Y.; Hashimoto, O.; Kawama, D.; Maruta, T.; Maxwell, V.; Mkrtchyan, A.; Nagao, S.; Nakamura, S. N.; Reinhold, J.; Shichijo, A.; Tang, L.; Taniya, N.; Wood, S. A.; Ye, Z.

2013-11-01

Aerogel and water Čherenkov detectors were employed to tag kaons for a Λ hypernuclear spectroscopic experiment which used the (e,e‧K+) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 gauss at the photomultiplier tubes for these detectors. These fields, which could not be easily passively shielded, would result in a lowered kaon detection efficiency if not mitigated. A bucking coil was placed on each photomultiplier tube to actively cancel this magnetic field, thus recovering kaon detection efficiency.

Fiber Bragg grating sensors for real-time monitoring of evacuation process

NASA Astrophysics Data System (ADS)

Guru Prasad, A. S.; Hegde, Gopalkrishna M.; Asokan, S.

2010-03-01

Fiber bragg grating (FBG) sensors have been widely used for number of sensing applications like temperature, pressure, acousto-ultrasonic, static and dynamic strain, refractive index change measurements and so on. Present work demonstrates the use of FBG sensors in in-situ measurement of vacuum process with simultaneous leak detection capability. Experiments were conducted in a bell jar vacuum chamber facilitated with conventional Pirani gauge for vacuum measurement. Three different experiments have been conducted to validate the performance of FBG sensor in monitoring vacuum creating process and air bleeding. The preliminary results of FBG sensors in vacuum monitoring have been compared with that of commercial Pirani gauge sensor. This novel technique offers a simple alternative to conventional method for real time monitoring of evacuation process. Proposed FBG based vacuum sensor has potential applications in vacuum systems involving hazardous environment such as chemical and gas plants, automobile industries, aeronautical establishments and leak monitoring in process industries, where the electrical or MEMS based sensors are prone to explosion and corrosion.

Studies of a Next-Generation Silicon-Photomultiplier-Based Time-of-Flight PET/CT System.

PubMed

Hsu, David F C; Ilan, Ezgi; Peterson, William T; Uribe, Jorge; Lubberink, Mark; Levin, Craig S

2017-09-01

This article presents system performance studies for the Discovery MI PET/CT system, a new time-of-flight system based on silicon photomultipliers. System performance and clinical imaging were compared between this next-generation system and other commercially available PET/CT and PET/MR systems, as well as between different reconstruction algorithms. Methods: Spatial resolution, sensitivity, noise-equivalent counting rate, scatter fraction, counting rate accuracy, and image quality were characterized with the National Electrical Manufacturers Association NU-2 2012 standards. Energy resolution and coincidence time resolution were measured. Tests were conducted independently on two Discovery MI scanners installed at Stanford University and Uppsala University, and the results were averaged. Back-to-back patient scans were also performed between the Discovery MI, Discovery 690 PET/CT, and SIGNA PET/MR systems. Clinical images were reconstructed using both ordered-subset expectation maximization and Q.Clear (block-sequential regularized expectation maximization with point-spread function modeling) and were examined qualitatively. Results: The averaged full widths at half maximum (FWHMs) of the radial/tangential/axial spatial resolution reconstructed with filtered backprojection at 1, 10, and 20 cm from the system center were, respectively, 4.10/4.19/4.48 mm, 5.47/4.49/6.01 mm, and 7.53/4.90/6.10 mm. The averaged sensitivity was 13.7 cps/kBq at the center of the field of view. The averaged peak noise-equivalent counting rate was 193.4 kcps at 21.9 kBq/mL, with a scatter fraction of 40.6%. The averaged contrast recovery coefficients for the image-quality phantom were 53.7, 64.0, 73.1, 82.7, 86.8, and 90.7 for the 10-, 13-, 17-, 22-, 28-, and 37-mm-diameter spheres, respectively. The average photopeak energy resolution was 9.40% FWHM, and the average coincidence time resolution was 375.4 ps FWHM. Clinical image comparisons between the PET/CT systems demonstrated the high quality of the Discovery MI. Comparisons between the Discovery MI and SIGNA showed a similar spatial resolution and overall imaging performance. Lastly, the results indicated significantly enhanced image quality and contrast-to-noise performance for Q.Clear, compared with ordered-subset expectation maximization. Conclusion: Excellent performance was achieved with the Discovery MI, including 375 ps FWHM coincidence time resolution and sensitivity of 14 cps/kBq. Comparisons between reconstruction algorithms and other multimodal silicon photomultiplier and non-silicon photomultiplier PET detector system designs indicated that performance can be substantially enhanced with this next-generation system. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes.

PubMed

Winter, S; Smith, A; Lappin, D; McDonagh, G; Kirk, B

2017-12-01

Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150 s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15 s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N = 9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

FOREWORD: 7th Symposium on Vacuum-based Science and Technology (SVBST2013)

NASA Astrophysics Data System (ADS)

Gulbiński, W.

2014-11-01

These are the proceedings of the 7th Symposium on Vacuum based Science and Technology organized in Kołobrzeg (PL) on November 19-21, 2013 by the Institute of Technology and Education, Koszalin University of Technology and the Clausius Tower Society under auspices of the Polish Vacuum Society (PTP) and the German Vacuum Society (DVG) and in collaboration with the BalticNet PlasmaTec and the Society of Vacuum Coaters (SVC). It was accompanied by the 12-th Annual Meeting of the German Vacuum Society. The mission of the Symposium is to provide a forum for presentation and exchange of expertise and research results in the field of vacuum and plasma science. After already six successful meetings organized alternately in Poland and Germany our goal is to continue and foster cooperation within the vacuum and plasma science community. This year, the Rudolf-Jaeckel Prize, awarded by the DVG for outstanding achievements in the field of vacuum based sciences, was presented to Dr Ute Bergner, president of the VACOM Vakuum Komponenten & Messtechnik GmbH and a member of our community. The full-day course organized in the framework of the Educational Program by the Society of Vacuum Coaters (SVC) and entitled: An Introduction to Physical Vapor Deposition (PVD) Processes was held on November 18, 2013 as a satellite event of the Symposium. The instructor was Prof. Ismat Shah from Delaware University (US). The Clausius Session, already traditionally organized during the Symposium was addressed this year to young generation. We invited our young colleagues to attend a series of educational lectures reporting on achievements in graphene science, scanning probe microscopy and plasma science. Lectures were given by: Prof. Jacek Baranowski from the Institute of Electronic Materials Technology in Warsaw, Prof. Teodor Gotszalk from the Wroclaw University of Technology and Prof. Holger Kersten from the Christian Albrechts University in Kiel. The Symposium was accompanied by an industry exhibition attended by the representatives of leading companies offering vacuum equipment, complete solutions for plasma based technology as well as advanced research equipment. Witold Gulbiński Michael Kopnarski Frank Richter Jan Walkowicz

A squeezed light source operated under high vacuum

PubMed Central

Wade, Andrew R.; Mansell, Georgia L.; Chua, Sheon S. Y.; Ward, Robert L.; Slagmolen, Bram J. J.; Shaddock, Daniel A.; McClelland, David E.

2015-01-01

Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments. PMID:26657616

A squeezed light source operated under high vacuum

NASA Astrophysics Data System (ADS)

Wade, Andrew R.; Mansell, Georgia L.; Chua, Sheon S. Y.; Ward, Robert L.; Slagmolen, Bram J. J.; Shaddock, Daniel A.; McClelland, David E.

2015-12-01

Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments.

Multivariate optical computing using a digital micromirror device for fluorescence and Raman spectroscopy.

PubMed

Smith, Zachary J; Strombom, Sven; Wachsmann-Hogiu, Sebastian

2011-08-29

A multivariate optical computer has been constructed consisting of a spectrograph, digital micromirror device, and photomultiplier tube that is capable of determining absolute concentrations of individual components of a multivariate spectral model. We present experimental results on ternary mixtures, showing accurate quantification of chemical concentrations based on integrated intensities of fluorescence and Raman spectra measured with a single point detector. We additionally show in simulation that point measurements based on principal component spectra retain the ability to classify cancerous from noncancerous T cells.

CLARO: an ASIC for high rate single photon counting with multi-anode photomultipliers

NASA Astrophysics Data System (ADS)

Baszczyk, M.; Carniti, P.; Cassina, L.; Cotta Ramusino, A.; Dorosz, P.; Fiorini, M.; Gotti, C.; Kucewicz, W.; Malaguti, R.; Pessina, G.

2017-08-01

The CLARO is a radiation-hard 8-channel ASIC designed for single photon counting with multi-anode photomultiplier tubes. Each channel outputs a digital pulse when the input signal from the photomultiplier crosses a configurable threshold. The fast return to baseline, typically within 25 ns, and below 50 ns in all conditions, allows to count up to 107 hits/s on each channel, with a power consumption of about 1 mW per channel. The ASIC presented here is a much improved version of the first 4-channel prototype. The threshold can be precisely set in a wide range, between 30 ke- (5 fC) and 16 Me- (2.6 pC). The noise of the amplifier with a 10 pF input capacitance is 3.5 ke- (0.6 fC) RMS. All settings are stored in a 128-bit configuration and status register, protected against soft errors with triple modular redundancy. The paper describes the design of the ASIC at transistor-level, and demonstrates its performance on the test bench.

Precision analysis of the photomultiplier response to ultra low signals

DOE PAGES

Degtiarenko, Pavel

2017-08-05

Here, a new computational model for the description of the photon detector response functions measured in conditions of low light is presented, together with examples of the observed photomultiplier signal amplitude distributions, successfully described using the parameterized model equation. In extension to the previously known approximations, the new model describes the underlying discrete statistical behavior of the photoelectron cascade multiplication processes in photon detectors with complex non-uniform gain structure of the first dynode. Important features of the model include the ability to represent the true single-photoelectron spectra from different photomultipliers with a variety of parameterized shapes, reflecting the variability inmore » the design and in the individual parameters of the detectors. The new software tool is available for evaluation of the detectors’ performance, response, and efficiency parameters that may be used in various applications including the ultra low background experiments such as the searches for Dark Matter and rare decays, underground neutrino studies, optimizing operations of the Cherenkov light detectors, help in the detector selection procedures, and in the experiment simulations.« less

A LYSO crystal array readout by silicon photomultipliers as compact detector for space applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kryemadhi, A.; Barner, L.; Grove, A.

Precise measurements of GeV range gamma rays help narrow down among var- ious gamma emission models and increase sensitivity for dark matter searches. Construction of precise as well as compact instruments requires detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled with small foot- print photo-detectors are suitable candidates. We prototyped a detector array consisting of four LYSO crystals where each crystal is read out by a 2x2 SensL ArrayJ60035 silicon photomultipliers. The LYSO crystals were chosen because of their good light yield, fast decay time, demonstrated radiation hardness,more » and small radiation length. Here, we used the silicon photomultiplier arrays as photo- detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic elds. We also studied the detector performance in the energy range of interest by exposing it to 2-16 GeV particles produced at the Test Beam Facility of Fermi National Accelerator Laboratory.« less

A LYSO crystal array readout by silicon photomultipliers as compact detector for space applications

DOE PAGES

Kryemadhi, A.; Barner, L.; Grove, A.; ...

2017-10-31

Precise measurements of GeV range gamma rays help narrow down among var- ious gamma emission models and increase sensitivity for dark matter searches. Construction of precise as well as compact instruments requires detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled with small foot- print photo-detectors are suitable candidates. We prototyped a detector array consisting of four LYSO crystals where each crystal is read out by a 2x2 SensL ArrayJ60035 silicon photomultipliers. The LYSO crystals were chosen because of their good light yield, fast decay time, demonstrated radiation hardness,more » and small radiation length. Here, we used the silicon photomultiplier arrays as photo- detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic elds. We also studied the detector performance in the energy range of interest by exposing it to 2-16 GeV particles produced at the Test Beam Facility of Fermi National Accelerator Laboratory.« less

Photomultiplier window materials under electron irradiation - Fluorescence and phosphorescence

NASA Technical Reports Server (NTRS)

Viehmann, W.; Eubanks, A. G.; Pieper, G. F.; Bredekamp, J. H.

1975-01-01

The fluorescence and phosphorescence of photomultiplier window materials under electron irradiation have been investigated using a Sr-90/Y-90 beta emitter as the electron source. Spectral emission curves of UV-grade, optical-grade, and electron-irradiated samples of MgF2 and LiF, and of CaF2, BaF2, sapphire, fused silica, and UV-transmitting glasses were obtained over the 200-650-nm spectral range. Fluorescence yields were determined on these materials utilizing photomultiplier tubes with cesium telluride, bialkali, and trialkali (S-20) photocathodes, respectively. Optical-grade MgF2 and LiF, as well as electron-irradiated UV-grade samples of these two materials, show enhanced fluorescence due to color-center formation and associated emission bands in the blue and red wavelength regions. Large variations in fluorescence intensities were found in UV-grade sapphire samples of different origins, particularly in the red end of the spectrum, presumably due to various amounts of chromium-ion content. Phosphorescence decay with time is best described by a sum of exponential terms, with time constants ranging from a few minutes to several days.

Investigation of Self Triggered Cosmic Ray Detectors using Silicon Photomultiplier

NASA Astrophysics Data System (ADS)

Knox, Adrian; Niduaza, Rommel; Hernandez, Victor; Ruiz, Daniel; Ramos, Daniel; Fan, Sewan; Fatuzzo, Laura; Ritt, Stefan

2015-04-01

The silicon photomultiplier (SiPM) is a highly sensitive light detector capable of measuring single photons. It costs a fraction of the photomultiplier tube and operates slightly above the breakdown voltage. At this conference we describe our investigation of SiPM, the multipixel photon counters (MPPC) from Hamamatsu as readout detectors for plastic scintillators working for detecting cosmic ray particles. Our setup consists of scintillator sheets embedded with blue to green wavelength shifting fibers optically coupled to MPPCs to detect scintillating light. Four detector assemblies would be constructed and arranged to work in self triggered mode. Using custom matching tee boxes, the amplified MPPC signals are fed to discriminators with threshold set to give a reasonable coincidence count rate. Moreover, the detector waveforms are digitized using a 5 Giga Samples per second waveform digitizer, the DRS4, and triggered with the coincidence logic to capture the MPPC waveforms. Offline analysis of the digitized waveforms is accomplished using the CERN package PAW and results of our experiments and the data analysis would also be discussed. US Department of Education Title V Grant Number PO31S090007.

Comparative Evaluation of Vacuum-based Surface Sampling ...

EPA Pesticide Factsheets

Journal Article Following a biological contamination incident, collection of surface samples is necessary to determine the extent and level of contamination, and to deem an area safe for reentry upon decontamination. Current sampling strategies targeting Bacillus anthracis spores prescribe vacuum-based methods for rough and/or porous surfaces. In this study, four commonly-used B. anthracis spore sampling devices (vacuum socks, 37 mm 0.8 µm MCE filter cassettes, 37 mm 0.3 µm PTFE filter cassettes, and 3MTM forensic filters) were comparatively evaluated for their ability to recover surface-associated spores. The vacuum sock device was evaluated at two sampling speeds (slow and fast), resulting in five total methods evaluated. Aerosolized spores (~105 cm-2) of a surrogate Bacillus species (Bacillus atrophaeus) were allowed to settle onto three material types (concrete, carpet, and upholstery). Ten replicate samples were collected using each vacuum method, from each of the three material types. In addition, stainless steel (i.e., nonporous) surfaces inoculated simultaneously were sampled with pre-moistened wipes. Recoveries from wipes of steel surfaces were utilized to verify the inoculum, and to normalize vacuum-based recoveries across trials. Recovery (CFU cm-2) and relative recovery (vacuum recovery/wipe recovery) were determined for each method and material type. Relative recoveries were compared by one-way and three-way ANOVA. Data analysis by one-

Vacuum-driven power-free microfluidics utilizing the gas solubility or permeability of polydimethylsiloxane (PDMS).

PubMed

Xu, Linfeng; Lee, Hun; Jetta, Deekshitha; Oh, Kwang W

2015-10-21

Suitable pumping methods for flow control remain a major technical hurdle in the path of biomedical microfluidic systems for point-of-care (POC) diagnostics. A vacuum-driven power-free micropumping method provides a promising solution to such a challenge. In this review, we focus on vacuum-driven power-free microfluidics based on the gas solubility or permeability of polydimethylsiloxane (PDMS); degassed PDMS can restore air inside itself due to its high gas solubility or gas permeable nature. PDMS allows the transfer of air into a vacuum through it due to its high gas permeability. Therefore, it is possible to store or transfer air into or through the gas soluble or permeable PDMS in order to withdraw liquids into the embedded dead-end microfluidic channels. This article provides a comprehensive look at the physics of the gas solubility and permeability of PDMS, a systematic review of different types of vacuum-driven power-free microfluidics, and guidelines for designing solubility-based or permeability-based PDMS devices, alongside existing applications. Advanced topics and the outlook in using micropumping that utilizes the gas solubility or permeability of PDMS will be also discussed. We strongly recommend that microfluidics and lab-on-chip (LOC) communities harness vacuum energy to develop smart vacuum-driven microfluidic systems.

Photoelectron yields of scintillation counters with embedded wavelength-shifting fibers read out with silicon photomultipliers

DOE PAGES

Artikov, Akram; Baranov, Vladimir; Blazey, Gerald C.; ...

2018-02-14

Photoelectron yields of extruded scintillation counters with titanium dioxide coating and embedded wavelength shifting fibers read out by silicon photomultipliers have been measured at the Fermilab Test Beam Facility using 120,GeV protons. The yields were measured as a function of transverse, longitudinal, and angular positions for a variety of scintillator compositions and reflective coating mixtures, fiber diameters, and photosensor sizes. Timing performance was also studied. These studies were carried out by the Cosmic Ray Veto Group of the Mu2e collaboration as part of their R\\&D program.

Photodetectors for scintillator proportionality measurement

NASA Astrophysics Data System (ADS)

Moses, William W.; Choong, Woon-Seng; Hull, Giulia; Payne, Steve; Cherepy, Nerine; Valentine, John D.

2009-10-01

We evaluate photodetectors for use in a Compton Coincidence apparatus designed for measuring scintillator proportionality. There are many requirements placed on the photodetector in these systems, including active area, linearity, and the ability to accurately measure low light levels (which implies high quantum efficiency and high signal-to-noise ratio). Through a combination of measurement and Monte Carlo simulation, we evaluate a number of potential photodetectors, especially photomultiplier tubes and hybrid photodetectors. Of these, we find that the most promising devices available are photomultiplier tubes with high (˜50%) quantum efficiency, although hybrid photodetectors with high quantum efficiency would be preferable.

Photoelectron yields of scintillation counters with embedded wavelength-shifting fibers read out with silicon photomultipliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artikov, Akram; Baranov, Vladimir; Blazey, Gerald C.

Photoelectron yields of extruded scintillation counters with titanium dioxide coating and embedded wavelength shifting fibers read out by silicon photomultipliers have been measured at the Fermilab Test Beam Facility using 120,GeV protons. The yields were measured as a function of transverse, longitudinal, and angular positions for a variety of scintillator compositions and reflective coating mixtures, fiber diameters, and photosensor sizes. Timing performance was also studied. These studies were carried out by the Cosmic Ray Veto Group of the Mu2e collaboration as part of their R\\&D program.

Gain control of photomultiplier tubes used in detecting differential absorption lidar returns

NASA Technical Reports Server (NTRS)

Allen, Robert J. (Inventor)

1989-01-01

A technique for controlling the gain of a photomultiplier tube (PMT) 20. A voltage divider (resistors 45-49 in FIG. 1 and zener diodes 60-65 in FIG. 3) is used to control the potentials on dynodes 5, 7, and 9 of PMT 20. Transistor switches 53 and 58 provide the control of the voltage divider in FIG. 1 and photodiodes 66, 67 and 70 provide the control in FIG. 3. The gain control of PMT 20 is in the range from 100% to less than 0.001% (100,000 to 1).

The nuclear radiation monitor for the Spacelab/Shuttle

NASA Technical Reports Server (NTRS)

Fishman, G. J.

1978-01-01

A 5 inch by 5 inch diameter sodium iodide scintillation crystal, viewed by a 5 inch photomultiplier was designed to be mounted near the center of the shuttle payload bay to quantitatively measure the neutron and gamma ray environment during the second Spacelab mission. The expected energy resolution is 8% FWHM at 662 keV. The detector will operate in an energy range from 0.1 to 20 MeV. A charged anticoincidence shield consisting of a 1 cm thick plastic scintillator viewed by three 2 inch photomultiplier tubes, covers the crystal detector which has nearly omnidirectional response.

Light detection and the wavelength shifter deposition in DEAP-3600

NASA Astrophysics Data System (ADS)

Broerman, B.; Retière, F.

2016-02-01

The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) uses liquid argon as a target medium to perform a direct-detection dark matter search. The 3600 kg liquid argon target volume is housed in a spherical acrylic vessel and viewed by a surrounding array of photomultiplier tubes. Ionizing particles in the argon volume produce scintillation light which must be wavelength shifted to be detected by the photomultiplier tubes. Argon scintillation and wavelength shifting, along with details on the application of the wavelength shifter to the inner surface of the acrylic vessel are presented.

On the prospects of application and development of solid-state photomultipliers for the task of analog detecting of pulsed optical signals

NASA Astrophysics Data System (ADS)

Bogdanov, S. V.; Kolobov, N. A.; Levin, E. V.; Pozdnyakov, Y. I.; Shubin, V. E.; Shushakov, D. A.; Sitarsky, K. Yu.; Torgovnikov, R. A.

2018-02-01

In this paper, we analyze the influence of the crosstalk level and the dynamic range on the basic characteristics of a silicon solid-state photomultiplier and demonstrate their importance for detecting of optical signals with backlight illumination, in particular, for LIDAR application. Experimental results obtained in the study of threshold and fluctuation parameters of detectors with different levels of crosstalk and dynamic range are presented. It is shown that the detector design combining a high dynamic range with a small crosstalk gives a noticeable advantage in such applications.

Sub-nanosecond ranging possibilities of optical radar at various signal levels and transmitted pulse widths

NASA Technical Reports Server (NTRS)

Poultney, S. K.

1971-01-01

The behavior of the photomultiplier is considered, as well as the method of derivation of the photomultiplier output pulse and its relation to the reflected light pulse width and amplitude, and the calibration of range precision and accuracy. Pulsed laser radars with light pulse widths of 30, 3, and 0.1 nanosec a considered, with the 0.1 nanosec system capable of highest precision in several modes of operation, including a high repetition rate, single photoelectron reception mode. An alternate calibration scheme using a fast, triggerable light pulser is described in detail.

A position sensitive microchannel photomultiplier for ultraviolet space astronomy

NASA Technical Reports Server (NTRS)

Lampton, M.; Siegmund, O. H. W.; Bixler, J.; Bowyer, S.

1986-01-01

The 25-mm microchannel-plate, position-sensitive UV astronomy photomultiplier tube presented is intended for the EOM-1 Spacelab Mission's FAUST payload and conducts wide-field imaging surveys in the VUV over the 1400-1800-A range. The sealed detector encompasses a CsI photocathode deposited on the inner surface of a MgF2 window, a stack of microchannel plates, and a wedge-and-strip two-dimensional position-sensing anode. Since the wedge-and-strip principle requires only three anode signals, flight electronics can be reduced to three charge amplifiers and three analog-to-digital converters.

Report on the lunar ranging at McDonald Observatory. [spark gap configuration and photomultiplier system

NASA Technical Reports Server (NTRS)

Silverberg, E. C.

1977-01-01

Range measurements to an accuracy of 5 cm were achieved following improvements in the laser oscillator configuration and the photomultiplier system. Modifications to the laser include a redesigned pockel cell mount to eliminate stressing of the cell crystal; an improved electrically triggered spark gap for sharpening the electrical pulse; the use of a brewster plate in the cavity to eliminate pre-pulsing; improved alignment for the oscillator system; and increased cavity lifetime through thin film polarizer technology. Laser calibration data are presented along with the lunar laser operations log for June to October 1977.

Photoelectron yields of scintillation counters with embedded wavelength-shifting fibers read out with silicon photomultipliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Artikov, Akram; Baranov, Vladimir; Blazey, Gerald C.

2018-05-01

Photoelectron yields of extruded scintillation counters with titanium dioxide coating and embedded wavelength shifting fibers read out by silicon photomultipliers have been measured at the Fermilab Test Beam Facility using 120\\,GeV protons. The yields were measured as a function of transverse, longitudinal, and angular positions for a variety of scintillator compositions and reflective coating mixtures, fiber diameters, and photosensor sizes. Timing performance was also studied. These studies were carried out by the Cosmic Ray Veto Group of the Mu2e collaboration as part of their R\\&D program.

Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

NASA Astrophysics Data System (ADS)

Cheng, Shaoyong; Xiu, Shixin; Wang, Jimei; Shen, Zhengchao

2006-11-01

The greenhouse effect of SF6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.

Design and prototype results of the FAST detector

NASA Astrophysics Data System (ADS)

Mozzanica, A.; Basset, M.; Caccia, M.; Corradini, M.; Leali, M.; Lodi Rizzini, E.; Prest, M.; Venturelli, L.; Vallazza, E.; Zurlo, N.

2006-11-01

A new fiber tracker is being developed for the ASACUSA experiment at the Antiproton Decelerator at CERN. The detector is based on 1 mm diameter scintillating fibers readout by HAMAMATSU 64 channel multianode photomultipliers (MA-PMTs) connected to a dedicated electronic chain. The paper gives a description of the testing procedures for time resolution, spatial resolution and efficiency measurements performed with standard NIM electronics and a commercial TDC and reports the results for different prototype detectors.

Semiconductor superlattice photodetectors

NASA Technical Reports Server (NTRS)

Chuang, S. L.; Hess, K.; Coleman, J. J.; Leburton, J. P.

1984-01-01

A superlattice photomultiplier and a photodetector based on the real space transfer mechanism were studied. The wavelength for the first device is of the order of a micron or flexible corresponding to the bandgap absorption in a semiconductor. The wavelength for the second device is in the micron range (about 2 to 12 microns) corresponding to the energy of the conduction band edge discontinuity between an Al/(sub x)Ga(sub 1-x)As and GaAs interface. Both devices are described.

Prospects of Silicon Photomultipliers for Ground-Based Cosmic Ray Experiments

NASA Astrophysics Data System (ADS)

Peters, Christine; Bretz, Thomas; Hebbeker, Thomas; Kemp, Julian; Lauscher, Markus; Middendorf, Lukas; Niggemann, Tim; Schumacher, Johannes

An established technique to study ultra-high-energy cosmic rays is the detection of extensive air showers induced in the atmosphere of the earth. Thereby, cascades of secondary particles are produced consisting of a hadronic, an electromagnetic and a muonic component. Especially the determination of the number of muons and the amount of fluorescence light produced during the shower development allows to draw conclusions on the mass and energy of the primary particle. Thus, these are important observables for air shower experiments like for instance the Pierre Auger Observatory in Argentina, and its AugerPrime upgrade in progress. The steady development of semiconductor devices in the last years resulted in highly improved photon sensors, e.g., silicon photomultipliers (SiPMs). The small package and moderate bias voltage (<100 V) of these silicon devices allow for compact and robust designs. Detailed detector simulations, the development of dedicated front-end electronics, as well as construction and investigation of detector prototypes, are needed to study the applicability of SiPMs for cosmic ray experiments. We present our findings for two different detector techniques: First, we present the fluorescence telescope, FAMOUS. Its basic principle is based on a Fresnel lens focusing the incoming light onto a camera instrumented with 61 pixels. Secondly, the benefit of the application of SiPMs is studied for scintillator detectors designed for an improved determination of the muonic component in air showers of current experiments.

A computer controlled signal preprocessor for laser fringe anemometer applications

NASA Technical Reports Server (NTRS)

Oberle, Lawrence G.

1987-01-01

The operation of most commercially available laser fringe anemometer (LFA) counter-processors assumes that adjustments are made to the signal processing independent of the computer used for reducing the data acquired. Not only does the researcher desire a record of these parameters attached to the data acquired, but changes in flow conditions generally require that these settings be changed to improve data quality. Because of this limitation, on-line modification of the data acquisition parameters can be difficult and time consuming. A computer-controlled signal preprocessor has been developed which makes possible this optimization of the photomultiplier signal as a normal part of the data acquisition process. It allows computer control of the filter selection, signal gain, and photo-multiplier voltage. The raw signal from the photomultiplier tube is input to the preprocessor which, under the control of a digital computer, filters the signal and amplifies it to an acceptable level. The counter-processor used at Lewis Research Center generates the particle interarrival times, as well as the time-of-flight of the particle through the probe volume. The signal preprocessor allows computer control of the acquisition of these data.Through the preprocessor, the computer also can control the hand shaking signals for the interface between itself and the counter-processor. Finally, the signal preprocessor splits the pedestal from the signal before filtering, and monitors the photo-multiplier dc current, sends a signal proportional to this current to the computer through an analog to digital converter, and provides an alarm if the current exceeds a predefined maximum. Complete drawings and explanations are provided in the text as well as a sample interface program for use with the data acquisition software.

Thermodynamic performance of multi-stage gradational lead screw vacuum pump

NASA Astrophysics Data System (ADS)

Zhao, Fan; Zhang, Shiwei; Sun, Kun; Zhang, Zhijun

2018-02-01

As a kind of dry mechanical vacuum pump, the twin-screw vacuum pump has an outstanding pumping performance during operation, widely used in the semiconductor industry. Compared with the constant lead screw (CLS) vacuum pump, the gradational lead screw (GLS) vacuum pump is more popularly applied in recent years. Nevertheless, not many comparative studies on the thermodynamic performance of GLS vacuum pump can be found in the literature. Our study focuses on one type of GLS vacuum pump, the multi-stage gradational lead screw (MGLS) vacuum pump, gives a detailed description of its construction and illustrates it with the drawing. Based on the structural analysis, the thermodynamic procedure is divided into four distinctive processes, including sucking process, transferring (compressing) process, backlashing process and exhausting process. The internal mechanism of each process is qualitatively illustrated and the mathematical expressions of seven thermodynamic parameters are given under the ideal situation. The performance curves of MGLS vacuum pump are plotted by MATLAB software and compared with those of the CLS vacuum pump in the same case. The results can well explain why the MGLS vacuum pump has more favorable pumping performance than the CLS vacuum pump in saving energy, reducing noise and heat dissipation.

Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

DOEpatents

Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

2013-02-12

A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

LYSO-based precision timing detectors with SiPM readout

NASA Astrophysics Data System (ADS)

Bornheim, A.; Hassanshahi, M. H.; Griffioen, M.; Mao, J.; Mangu, A.; Peña, C.; Spiropulu, M.; Xie, S.; Zhang, Z.

2018-07-01

Particle detectors based on scintillation light are particularly well suited for precision timing applications with resolutions of a few 10's of ps. The large primary signal and the initial rise time of the scintillation light result in very favorable signal-to-noise conditions with fast signals. In this paper we describe timing studies using a LYSO-based sampling calorimeter with wavelength-shifting capillary light extraction and silicon photomultipliers as photosensors. We study the contributions of various steps of the signal generation to the total time resolution, and demonstrate its feasibility as a radiation-hard technology for calorimeters at high intensity hadron colliders.

Hyperspectral cytometry.

PubMed

Grégori, Gérald; Rajwa, Bartek; Patsekin, Valery; Jones, James; Furuki, Motohiro; Yamamoto, Masanobu; Paul Robinson, J

2014-01-01

Hyperspectral cytometry is an emerging technology for single-cell analysis that combines ultrafast optical spectroscopy and flow cytometry. Spectral cytometry systems utilize diffraction gratings or prism-based monochromators to disperse fluorescence signals from multiple labels (organic dyes, nanoparticles, or fluorescent proteins) present in each analyzed bioparticle onto linear detector arrays such as multianode photomultipliers or charge-coupled device sensors. The resultant data, consisting of a series of characterizing every analyzed cell, are not compensated by employing the traditional cytometry approach, but rather are spectrally unmixed utilizing algorithms such as constrained Poisson regression or non-negative matrix factorization. Although implementations of spectral cytometry were envisioned as early as the 1980s, only recently has the development of highly sensitive photomultiplier tube arrays led to design and construction of functional prototypes and subsequently to introduction of commercially available systems. This chapter summarizes the historical efforts and work in the field of spectral cytometry performed at Purdue University Cytometry Laboratories and describes the technology developed by Sony Corporation that resulted in release of the first commercial spectral cytometry system-the Sony SP6800. A brief introduction to spectral data analysis is also provided, with emphasis on the differences between traditional polychromatic and spectral cytometry approaches.

Development and calibration of a new gamma camera detector using large square Photomultiplier Tubes

NASA Astrophysics Data System (ADS)

Zeraatkar, N.; Sajedi, S.; Teimourian Fard, B.; Kaviani, S.; Akbarzadeh, A.; Farahani, M. H.; Sarkar, S.; Ay, M. R.

2017-09-01

Large area scintillation detectors applied in gamma cameras as well as Single Photon Computed Tomography (SPECT) systems, have a major role in in-vivo functional imaging. Most of the gamma detectors utilize hexagonal arrangement of Photomultiplier Tubes (PMTs). In this work we applied large square-shaped PMTs with row/column arrangement and positioning. The Use of large square PMTs reduces dead zones in the detector surface. However, the conventional center of gravity method for positioning may not introduce an acceptable result. Hence, the digital correlated signal enhancement (CSE) algorithm was optimized to obtain better linearity and spatial resolution in the developed detector. The performance of the developed detector was evaluated based on NEMA-NU1-2007 standard. The acquired images using this method showed acceptable uniformity and linearity comparing to three commercial gamma cameras. Also the intrinsic and extrinsic spatial resolutions with low-energy high-resolution (LEHR) collimator at 10 cm from surface of the detector were 3.7 mm and 7.5 mm, respectively. The energy resolution of the camera was measured 9.5%. The performance evaluation demonstrated that the developed detector maintains image quality with a reduced number of used PMTs relative to the detection area.

Receiver performance of laser ranging measurements between the Lunar Observer and a subsatellite for lunar gravity studies

NASA Technical Reports Server (NTRS)

Davidson, Frederic M.; Sun, Xiaoli

1992-01-01

The optimal receiver for a direct detection laser ranging system for slow Doppler frequency shift measurement is shown to consist of a phase tracking loop which can be implemented approximately as a phase lock loop with a 2nd or 3rd order loop filter. The laser transmitter consists of an AlGaAs laser diode at a wavelength of about 800 nm and is intensity modulated by a sinewave. The receiver performance is shown to be limited mainly by the preamplifier thermal noise when a silicon avalanche photodiode is used. A high speed microchannel plate photomultiplier tube is shown to outperform a silicon APD despite its relatively low quantum efficiency at wavelengths near 800 nm. The maximum range between the Lunar Observer and the subsatellite for lunar gravity studies is shown to be about 620 km when using a state-of-the-art silicon APD and about 1000 km when using a microchannel plate photomultiplier tube in order to achieve a relative velocity measurement accuracy of 1 millimeter per second. Other parameters such as the receiver time base jitter and drift also limit performance and have to be considered in the design of an actual system.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, Robert G.; AGIS Photodetector Group; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Horan, D.; Mukherjee, R.; Tajima, H.; Williams, D.

2008-03-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. It is being designed to achieve a significant improvement in sensitivity compared to current Imaging Air Cherenkov Telescope (IACT) Arrays. One of the main requirements in order that AGIS fulfill this goal will be to achieve higher angular resolution than current IACTs. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to less than 0.05 deg, i.e. two to three times smaller than the pixel size of current IACT cameras. With finer pixelation and the plan to deploy on the order of 100 telescopes in the AGIS array, the channel count will exceed 1,000,000 imaging pixels. High uniformity and long mean time-to-failure will be important aspects of a successful photodetector technology choice. Here we present alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs). Results from laboratory testing of MAPMTs and SiPMs are presented along with results from the first incorporation of these devices in cameras on test bed Cherenkov telescopes.

Parameter Extraction Method for the Electrical Model of a Silicon Photomultiplier

NASA Astrophysics Data System (ADS)

Licciulli, Francesco; Marzocca, Cristoforo

2016-10-01

The availability of an effective electrical model, able to accurately reproduce the signals generated by a Silicon Photo-Multiplier coupled to the front-end electronics, is mandatory when the performance of a detection system based on this kind of detector has to be evaluated by means of reliable simulations. We propose a complete extraction procedure able to provide the whole set of the parameters involved in a well-known model of the detector, which includes the substrate ohmic resistance. The technique allows achieving very good quality of the fit between simulation results provided by the model and experimental data, thanks to accurate discrimination between the quenching and substrate resistances, which results in a realistic set of extracted parameters. The extraction procedure has been applied to a commercial device considering a wide range of different conditions in terms of input resistance of the front-end electronics and interconnection parasitics. In all the considered situations, very good correspondence has been found between simulations and measurements, especially for what concerns the leading edge of the current pulses generated by the detector, which strongly affects the timing performance of the detection system, thus confirming the effectiveness of the model and the associated parameter extraction technique.

Dimensionless parameterization of lidar for laser remote sensing of the atmosphere and its application to systems with SiPM and PMT detectors.

PubMed

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.

Vacuum system of the cyclotrons in VECC, Kolkata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Anindya; Bhole, R.B.; Akhtar, J.

2011-07-01

The vacuum system of the K=130 Room Temperature Cyclotron (RTC) (operational since 1978) has been recently modernized and the same of the K{sub bend}=520 Superconducting Cyclotron (SCC), currently under commissioning, is being deployed for remote monitoring and control. The vacuum system of RTC is designed to achieve and maintain vacuum level of 2 X 10{sup -6} mbar inside 23 m{sup 3} volume of Resonator tank and DEE tank. This has been upgraded by replacing several valves, Freon units, gauges and pumps. The relay based manual control system has been replaced by PLC based automated system. The SCC vacuum system alsomore » has an elaborate arrangement comprising of turbo molecular pumping modules with associated isolation valves and characteristic gauges. This paper describes essential elements, typically used to obtain high (1X10{sup -7} mbar) vacuum using rotary pumps, diffusion pumps and cold traps/turbo-molecular pumps and other system components such as valves, gauges and baffles. The supervisory control methodology/scheme of both the vacuum systems, developed in-house using EPICS (Experimental Physics and Industrial Control System), a standard open-source software tool for designing distributed control system, is also elaborated here. (author)« less

Fission-fragment detector for DANCE based on thin scintillating films

NASA Astrophysics Data System (ADS)

Rusev, G.; Roman, A. R.; Daum, J. K.; Springs, R. K.; Bond, E. M.; Jandel, M.; Baramsai, B.; Bredeweg, T. A.; Couture, A.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Ullmann, J. L.; Walker, C. L.

2015-12-01

A fission-fragment detector based on thin scintillating films has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing 4 π detection of the fission fragments. The scintillation photons were registered with silicon photomultipliers. A measurement of the 235U (n , f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described.

Quantum efficiencies of several VUV-sensitive photomultiplier tubes

NASA Astrophysics Data System (ADS)

Dorenbos, P.; de Haas, J. T. M.; Visser, R.; van Eijk, C. W. E.; Hollander, R. W.

1993-02-01

The quantum efficiencies (QEs) of several VUV sensitive photon detectors were determined and compared with each other. We tested the following photomultiplier tubes (PMTs): five Philips XP2020Qs, one Hamamatsu R2059, and one Thorn EMI 9426. We also tested a Na-salicylate coated glass window combined with a Philips XP2020 PMT. At wavelengths smaller than 230 nm, the QEs of both the Thorn EMI and Philips PMTs appear significantly better than the QE of the Hamamatsu PMT. Furthermore, at these wavelengths, the QE of the XP2020Q PMTs was found to be much higher than advertised in the manufacturers catalogues.

Studies of relative gain and timing response of fine-mesh photomultiplier tubes in high magnetic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulkosky, V.; Allison, L.; Barber, C.

We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regards to their gain and timing resolution in magnetic fields up to 1.9 T. Our results show that the H6614-70 assembly can operate reliably in magnetic fields exceeding 1.5 T, while preserving a reasonable timing resolution even with a gain reduction of a factor of ~100. The reduction of the relative gain of the H6152-70 is similar to the H6614-70's near 1.5 T, but its timing resolution worsens considerably at this high field.

Portable instrument for inspecting irradiated nuclear fuel assemblies

DOEpatents

Nicholson, Nicholas; Dowdy, Edward J.; Holt, David M.; Stump, Jr., Charles J.

1985-01-01

A portable instrument for measuring induced Cerenkov radiation associated with irradiated nuclear fuel assemblies in a water-filled storage pond is disclosed. The instrument includes a photomultiplier tube and an image intensifier which are operable in parallel and simultaneously by means of a field lens assembly and an associated beam splitter. The image intensifier permits an operator to aim and focus the apparatus on a submerged fuel assembly. Once the instrument is aimed and focused, an illumination reading can be obtained with the photomultiplier tube. The instrument includes a lens cap with a carbon-14/phosphor light source for calibrating the apparatus in the field.

Multianode Photomultiplier Tube Alignment for the MINERvA Experiment at Fermilab

NASA Astrophysics Data System (ADS)

Bruno, Jorge

2006-10-01

The MINERvA experiment (Main INjector ExpeRiment vA) at FNAL will study the neutrino-nucleon and neutrino-nucleus interaction. The light collection from the detector will be done via optic fibers using Hamamatsu H8804 64-channel photomultiplier tubes (PMT). Each PMT channel needs to be precisely aligned with the corresponding optic fiber. The MINERvA PMT optical boxes contain precision machined optic ``cookies'' which capture the 8x8 array of optic fibers. Each PMT-cookie pair needs to be aligned as precisely as possible. This contribution will describe the alignment setup and procedure implemented at James Madison University.

Construction and tests of a fine granularity lead-scintillating fibers calorimeter

NASA Astrophysics Data System (ADS)

Branchini, P.; Ceradini, F.; Corradi, G.; Di Micco, B.; Passeri, A.

2009-04-01

We report the construction and the tests of a small prototype of the lead-scintillating fiber calorimeter of the KLOE experiment, instrumented with multianode photomultipliers to obtain a 16 times finer readout granularity. The prototype is 15 cm wide, 15 radiation lengths deep and is made of 200 layers of fibers 50 cm long. On one side it is read out with an array of 3×5 multianode photomultipliers Hamamatsu type R8900-M16, each segmented with 4×4 anodes, the read out granularity being 240 pixels of 11 × 11 mm2 corresponding to about 64 scintillating fibers each. These are interfaced to the 6 × 6 mm2 pixeled photocathode with truncated pyramid light guides made of Bicron BC-800 plastic to partially transmit the UV light. Each photomultiplier provides also an OR of the 16 last dynodes that is used for trigger. The response of the individual anodes, their relative gain and cross-talk has been measured with the light (440 nm) of a laser illuminating only few fibers on the side opposite to the readout. We finally present the first results of the calorimeter response to cosmic rays in auto-trigger mode.

A prototype of fine granularity lead-scintillating fiber calorimeter with imaging read out

NASA Astrophysics Data System (ADS)

Branchini, P.; Ceradini, F.; Corradi, G.; Di Micco, B.; Passeri, A.

2009-12-01

The construction and tests performed on a smal prototype of lead-scintillating fiber calorimeter instrumented with multianode photomultipliers are reported. The prototype is 15 cm wide, 15 radiation lenghts deep and is made of 200 layers of 50 cm long fibers. One side of the calorimeter has been instrumented with an array of 3 × 5 multianode R8900-M16 Hamamatsu photomultipliers, each segmented with a matrix of 4 × 4 anodes. The read-out granularity is 240 pixels 11 × 11 mm 2 reading about 64 fibers each. They are interfaced to the 6 × 6 mm 2 pixelled photocade with truncated pyramid light guides made of BC-800 plastic, UV transparent. Moreover each photomultiplier provides also the OR information of the last 12 dynodes. This information can be useful for trigger purposes. The response of the individual anodes, their relative gain and cross-talk has been measured with a 404 nm picosecond laser illuminating only a few fibers on the opposite side of the read-out. We also present first results of the calorimeter response to cosmic rays and electron beam data collected at BTF facility in Frascati.

New uses of position-sensitive photomultiplier tubes

NASA Astrophysics Data System (ADS)

Gordon, Jeffrey S.; Redus, Robert H.; Nagarkar, Vivek V.; Squillante, Michael R.

1992-12-01

Recent advances in photomultiplier tube technology have led to the availability of position sensitive photomultiplier tubes (PSPMTs). These tubes make it possible to build a new generation of imaging instruments for gamma rays and other types of ionizing radiation. We have investigated the use of these tubes for the construction of several prototype instruments. The first application investigated measures the quantity and distribution of radioactive compounds on filter papers used in microbiology research. The intent of this instrument is to replace film autoradiography with an electronic imaging system which can analyze samples 75 to 110 times faster than film. The second application involved the development of an intraoperative imaging probe to help surgeons identify cancerous tissue and ensure its complete removal. This instrument will replace a non-imaging probe now in use at many hospitals. A third prototype instrument under evaluation is an imaging nuclear survey system which obtains both a video and gamma ray image for the purpose of locating and quantifying radioactive materials. This system would be used at nuclear power plants and radioactive materials preparation facilities. A modification of this system could be built into robots used for inspecting and repairing power plants.

Investigation of the Effect of Temperature and Light Emission from Silicon Photomultiplier Detectors

NASA Astrophysics Data System (ADS)

Ruiz Castruita, Daniel; Ramos, Daniel; Hernandez, Victor; Niduaza, Rommel; Konx, Adrian; Fan, Sewan; Fatuzzo, Laura; Ritt, Stefan

2015-04-01

The silicon photomultiplier (SiPM) is an extremely sensitive light detector capable of measuring very dim light and operates as a photon-number resolving detector. Its high gain comes from operating at slightly above the breakdown voltage, which is also accompanied by a high dark count rate. At this conference poster session we describe our investigation of using SiPMs, the multipixel photon counters (MPPC) from Hamamatsu, as readout detectors for development in a cosmic ray scintillating detector array. Our research includes implementation of a novel design that automatically adjusts for the bias voltage to the MPPC detectors to compensate for changes in the ambient temperature. Furthermore, we describe our investigations for the MPPC detector characteristics at different bias voltages, temperatures and light emission properties. To measure the faint light emitted from the MPPC we use a photomultiplier tube capable of detecting single photons. Our data acquisition setup consists of a 5 Giga sample/second waveform digitizer, the DRS4, triggered to capture the MPPC detector waveforms. Analysis of the digitized waveforms, using the CERN package PAW, would be discussed and presented. US Department of Education Title V Grant PO31S090007.

SiPM photosensors and fast timing readout for the Barrel Time-of-Flight detector in bar PANDA

NASA Astrophysics Data System (ADS)

Suzuki, K.

2018-03-01

The Barrel Time-of-Flight detector system will be installed in the upcoming bar PANDA experiment at FAIR in Germany. The detector has a barrel shape of phi=0.5 m and 1.8 m long, covering about 5 m2, which corresponds to the laboratory polar angle coverage of 22o<θ<140o. The detector is a scintillation tile hodoscope. A single scintillation tile segment has a dimension of 90× 30 mm2 and 5 mm thickness, and photons are detected by Silicon Photomultipliers at both ends. 4 Silicon Photomultipliers are combined to work as a single sensor in order to increase the sensitive area and to improve the timing performance. In total, the system consists of 1920 scintillator tiles, 3840 readout channels, and makes use of 15360 Silicon Photomultiplier sensors. In this paper, the requirement, design and the result of an actual performance test of the bar PANDA Barrel Time-of-Flight detector are presented. The test shows that the current design fulfils satisfactorily the required timing performance (σt~ 56 ps) and the timing performance depends little on the hit position on the surface.

Final Technical Report- Radiation Hard Tight Pitch GaInP SPAD Arrays for High Energy Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harmon, Eric S.

The specialized photodetectors used in high energy physics experiments often need to remain extremely sensitive for years despite radiation induced damage caused by the constant bombardment of high energy particles. To solve this problem, LightSpin Technologies, Inc. in collaboration with Prof. Bradley Cox and the University of Virginia is developing radiation-hard GaInP photodetectors which are projected to be extraordinarily radiation hard, theoretically capable of withstanding a 100,000-fold higher radiation dose than silicon. In this Phase I SBIR project, LightSpin investigated the performance and radiation hardness of fifth generation GaInP SPAD arrays. These fifth generation devices used a new planar processingmore » approach that enables very tight pitch arrays to be produced. High performance devices with SPAD pitches of 11, 15, and 25 μm were successfully demonstrated, which greatly increased the dynamic range and maximum count rate of the devices. High maximum count rates are critical when considering radiation hardness, since radiation damage causes a proportional increase in the dark count rate, causing SPAD arrays with low maximum count rates (large SPAD pitches) to fail. These GaInP SPAD array Photomultiplier Chips™ were irradiated with protons, electrons, and neutrons. Initial irradiation results were disappointing, with the post-irradiation devices exhibiting excessively high dark currents. The degradation was traced to surface leakage currents that were largely eliminated through the use of trenches etched around the exterior of the Photomultiplier Chip™ (not between SPAD elements). A second round of irradiations on Photomultiplier Chips™ with trenches proved substantially more successful, with post-irradiation dark currents remaining relatively low, though dark count rates were observed to increase at the highest doses. Preliminary analysis of the post-irradiation devices is promising … many of the irradiated Photomultiplier Chips™ still exhibit good gain characteristics after 1E12/cm 2 – 1E13/cm 2 doses and have apparent dark count rates that are lower than the apparent dark count rates published for irradiation of silicon SPAD arrays (silicon photomultipliers or SiPMs). Some post-irradiation results are still pending because the samples will still too radioactive to be shipped back from the irradiation facility for post-irradiation testing.« less

Opto-mechanical design of vacuum laser resonator for the OSQAR experiment

NASA Astrophysics Data System (ADS)

Hošek, Jan; Macúchová, Karolina; Nemcová, Šárka; Kunc, Štěpán.; Šulc, Miroslav

2015-01-01

This paper gives short overview of laser-based experiment OSQAR at CERN which is focused on search of axions and axion-like particles. The OSQAR experiment uses two experimental methods for axion search - measurement of the ultra-fine vacuum magnetic birefringence and a method based on the "Light shining through the wall" experiment. Because both experimental methods have reached its attainable limits of sensitivity we have focused on designing a vacuum laser resonator. The resonator will increase the number of convertible photons and their endurance time within the magnetic field. This paper presents an opto-mechanical design of a two component transportable vacuum laser resonator. Developed optical resonator mechanical design allows to be used as a 0.8 meter long prototype laser resonator for laboratory testing and after transportation and replacement of the mirrors it can be mounted on the LHC magnet in CERN to form a 20 meter long vacuum laser resonator.

A High Vacuum High Speed Ion Pump

DOE R&D Accomplishments Database

Foster, J. S. Jr.; Lawrence, E. O.; Lofgren, E. J.

1952-08-27

A vacuum pump based on the properties of a magnetically collimated electric discharge is described. It has a speed in the range 3000 to 7000 liters a second and a base pressure in the order of 10{sup -6} mm. (auth)

SIGHT - A balloon borne hard X-ray telescope

NASA Technical Reports Server (NTRS)

Wilkerson, J.; Edberg, T. K.; Hurley, K.; Lin, R. P.; Parsons, A.

1991-01-01

The authors report on progress toward developing a large-area, high-pressure xenon gas scintillator for use in hard X-ray astrophysics. Proof test results for a low-mass pressure vessel are presented. The design of a high-voltage multiplier board operating inside the scintillation chamber is discussed. The development of tetrakis-dimethylamine-thylene (TMAE)-based proportional tubes for detecting primary scintillation in the xenon is described. Finally, Monte Carlo tests of a scheme to use conventional photomultiplier tubes are discussed.

Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph.

PubMed

Moskal, P; Rundel, O; Alfs, D; Bednarski, T; Białas, P; Czerwiński, E; Gajos, A; Giergiel, K; Gorgol, M; Jasińska, B; Kamińska, D; Kapłon, Ł; Korcyl, G; Kowalski, P; Kozik, T; Krzemień, W; Kubicz, E; Niedźwiecki, Sz; Pałka, M; Raczyński, L; Rudy, Z; Sharma, N G; Słomski, A; Silarski, M; Strzelecki, A; Wieczorek, A; Wiślicki, W; Witkowski, P; Zieliński, M; Zoń, N

2016-03-07

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the [Formula: see text] configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the [Formula: see text] matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of [Formula: see text]0.170 ns for 15 cm axial field-of-view (AFOV) and [Formula: see text]0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

NASA Astrophysics Data System (ADS)

Moskal, P.; Rundel, O.; Alfs, D.; Bednarski, T.; Białas, P.; Czerwiński, E.; Gajos, A.; Giergiel, K.; Gorgol, M.; Jasińska, B.; Kamińska, D.; Kapłon, Ł.; Korcyl, G.; Kowalski, P.; Kozik, T.; Krzemień, W.; Kubicz, E.; Niedźwiecki, Sz; Pałka, M.; Raczyński, L.; Rudy, Z.; Sharma, N. G.; Słomski, A.; Silarski, M.; Strzelecki, A.; Wieczorek, A.; Wiślicki, W.; Witkowski, P.; Zieliński, M.; Zoń, N.

2016-03-01

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2× 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2× 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of ≈ 0.170 ns for 15 cm axial field-of-view (AFOV) and ≈ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.

Performance study of the gamma-ray bursts polarimeter POLAR

NASA Astrophysics Data System (ADS)

Sun, J. C.; Wu, B. B.; Bao, T. W.; Batsch, T.; Bernasconi, T.; Britvitch, I.; Cadoux, F.; Cernuda, I.; Chai, J. Y.; Dong, Y. W.; Gauvin, N.; Hajdas, W.; He, J. J.; Kole, M.; Kong, M. N.; Kong, S. W.; Lechanoine-Leluc, C.; Li, Lu; Liu, J. T.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Produit, N.; Rapin, D.; Rutczynska, A.; Rybka, D.; Shi, H. L.; Song, L. M.; Szabelski, J.; Wang, R. J.; Wen, X.; Xiao, H. L.; Xiong, S. L.; Xu, H. H.; Xu, M.; Zhang, L.; Zhang, L. Y.; Zhang, S. N.; Zhang, X. F.; Zhang, Y. J.; Zwolinska, A.

2016-07-01

The Gamma-ray Burst Polarimeter-POLAR is a highly sensitive detector which is dedicated to the measurement of GRB's polarization with a large effective detection area and a large field of view (FOV). The optimized performance of POLAR will contribute to the capture and measurement of the transient sources like GRBs and Solar Flares. The detection energy range of POLAR is 50 keV 500 keV, and mainly dominated by the Compton scattering effect. POLAR consists of 25 detector modular units (DMUs), and each DMU is composed of low Z material Plastic Scintillators (PS), multi-anode photomultipliers (MAPMT) and multi-channel ASIC Front-end Electronics (FEE). POLAR experiment is an international collaboration project involving China, Switzerland and Poland, and is expected to be launched in September in 2016 onboard the Chinese space laboratory "Tiangong-2 (TG-2)". With the efforts from the collaborations, POLAR has experienced the Demonstration Model (DM) phase, Engineering and Qualification Model (EQM) phase, Qualification Model (QM) phase, and now a full Flight Model (FM) of POLAR has been constructed. The FM of POLAR has passed the environmental acceptance tests (thermal cycling, vibration, shock and thermal vacuum tests) and experienced the calibration tests with both radioactive sources and 100% polarized Gamma-Ray beam at ESRF after its construction. The design of POLAR, Monte-Carlo simulation analysis, as well as the performance test results will all be introduced in this paper.

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters

PubMed Central

Calfee, M. Worth; Rose, Laura J.; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2016-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37 mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p ≤ 0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p > 0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. PMID:24184312

Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters.

PubMed

Calfee, M Worth; Rose, Laura J; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

2014-01-01

The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p≤0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p>0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident. Published by Elsevier B.V.

Indigenous Manufacturing realization of TWIN Source

NASA Astrophysics Data System (ADS)

Pandey, R.; Bandyopadhyay, M.; Parmar, D.; Yadav, R.; Tyagi, H.; Soni, J.; Shishangiya, H.; Sudhir Kumar, D.; Shah, S.; Bansal, G.; Pandya, K.; Parmar, K.; Vuppugalla, M.; Gahlaut, A.; Chakraborty, A.

2017-04-01

TWIN source is two RF driver based negative ion source that has been planned to bridge the gap between single driver based ROBIN source (currently operational) and eight river based DNB source (to be operated under IN-TF test facility). TWIN source experiments have been planned at IPR keeping the objective of long term domestic fusion programme to gain operational experiences on vacuum immersed multi driver RF based negative ion source. High vacuum compatible components of twin source are designed at IPR keeping an aim on indigenous built in attempt. These components of TWIN source are mainly stainless steel and OFC-Cu. Being high heat flux receiving components, one of the major functional requirements is continuous heat removal via water as cooling medium. Hence for the purpose stainless steel parts are provided with externally milled cooling lines and that shall be covered with a layer of OFC-cu which would be on the receiving side of high heat flux. Manufacturability of twin source components requires joining of these dissimilar materials via process like electrode position, electron beam welding and vacuum brazing. Any of these manufacturing processes shall give a vacuum tight joint having proper joint strength at operating temperature and pressure. Taking the indigenous development effort vacuum brazing (in non-nuclear environment) has been opted for joining of dissimilar materials of twin source being one of the most reliable joining techniques and commercially feasible across the suppliers of country. Manufacturing design improvisation for the components has been done to suit the vacuum brazing process requirement and to ease some of the machining without comprising over the functional and operational requirements. This paper illustrates the details on the indigenous development effort, design improvisation to suits manufacturability, vacuum brazing basics and its procedures for twin source components.

Highly multiplexed signal readout for a time-of-flight positron emission tomography detector based on silicon photomultipliers.

PubMed

Cates, Joshua W; Bieniosek, Matthew F; Levin, Craig S

2017-01-01

Maintaining excellent timing resolution in the generation of silicon photomultiplier (SiPM)-based time-of-flight positron emission tomography (TOF-PET) systems requires a large number of high-speed, high-bandwidth electronic channels and components. To minimize the cost and complexity of a system's back-end architecture and data acquisition, many analog signals are often multiplexed to fewer channels using techniques that encode timing, energy, and position information. With progress in the development SiPMs having lower dark noise, after pulsing, and cross talk along with higher photodetection efficiency, a coincidence timing resolution (CTR) well below 200 ps FWHM is now easily achievable in single pixel, bench-top setups using 20-mm length, lutetium-based inorganic scintillators. However, multiplexing the output of many SiPMs to a single channel will significantly degrade CTR without appropriate signal processing. We test the performance of a PET detector readout concept that multiplexes 16 SiPMs to two channels. One channel provides timing information with fast comparators, and the second channel encodes both position and energy information in a time-over-threshold-based pulse sequence. This multiplexing readout concept was constructed with discrete components to process signals from a [Formula: see text] array of SensL MicroFC-30035 SiPMs coupled to [Formula: see text] Lu 1.8 Gd 0.2 SiO 5 (LGSO):Ce (0.025 mol. %) scintillators. This readout method yielded a calibrated, global energy resolution of 15.3% FWHM at 511 keV with a CTR of [Formula: see text] FWHM between the 16-pixel multiplexed detector array and a [Formula: see text] LGSO-SiPM reference detector. In summary, results indicate this multiplexing scheme is a scalable readout technique that provides excellent coincidence timing performance.

Vacuum-induced quantum memory in an opto-electromechanical system

NASA Astrophysics Data System (ADS)

Qin, Li-Guo; Wang, Zhong-Yang; Wu, Shi-Chao; Gong, Shang-Qing; Ma, Hong-Yang; Jing, Jun

2018-03-01

We propose a scheme to implement electrically controlled quantum memory based on vacuum-induced transparency (VIT) in a high-Q tunable cavity, which is capacitively coupled to a mechanically variable capacitor by a charged mechanical cavity mirror as an interface. We analyze the changes of the cavity photons arising from vacuum-induced-Raman process and discuss VIT in an atomic ensemble trapped in the cavity. By slowly adjusting the voltage on the capacitor, the VIT can be adiabatically switched on or off, meanwhile, the transfer between the probe photon state and the atomic spin state can be electrically and adiabatically modulated. Therefore, we demonstrate a vacuum-induced quantum memory by electrically manipulating the mechanical mirror of the cavity based on electromagnetically induced transparency mechanism.

Study of Vacuum Energy Physics for Breakthrough Propulsion

NASA Technical Reports Server (NTRS)

Millis, Marc G. (Technical Monitor); Maclay, G. Jordan; Hammer, Jay; Clark, Rod; George, Michael; Kim, Yeong; Kir, Asit

2004-01-01

This report summarizes the accomplishments during a three year research project to investigate the use of surfaces, particularly in microelectromechanical systems (MEMS), to exploit quantum vacuum forces. During this project, we developed AFM instrumentation to repeatably measure Casimir forces in the nanoNewton range at 10 6 torr, designed an experiment to measure attractive and repulsive quantum vacuum forces, developed a QED based theory of Casimir forces that includes non-ideal material properties for rectangular cavities and for multilayer slabs, developed theoretical models for a variety of microdevices utilizing vacuum forces, applied vacuum physics to a gedanken spacecraft, and investigated a new material with a negative index of refraction.

Portable instrument for inspecting irradiated nuclear-fuel assemblies in a water-filled storage pond by measurement of induced Cerenkov radiation

DOEpatents

Nicholson, N.; Dowdy, E.J.; Holt, D.M.; Stump, C.J. Jr.

1982-05-13

A portable instrument for measuring induced Cerenkov radiation associated with irradiated nuclear fuel assemblies in a water-filled storage pond is disclosed. The instrument includes a photomultiplier tube and an image intensifier which are operable in parallel and simultaneously by means of a field lens assembly and an associated beam splitter. The image intensifier permits an operator to aim and focus the apparatus on a submerged fuel assembly. Once the instrument is aimed and focused, an illumination reading can be obtained with the photomultiplier tube. The instrument includes a lens cap with a carbon-14/phosphor light source for calibrating the apparatus in the field.

Modeling the low-light response of photomultiplier tubes

NASA Astrophysics Data System (ADS)

Maxwell, Patrick; Niculescu, Ioana

2017-09-01

A number of crucial experiments exploring the intricate tomography of protons and neutrons will be carried out in Hall A at Jefferson Lab using the SuperBigBite Spectrometer (SBS), a large acceptance magnetic spectrometer sporting 0.5% momentum and 0.5 mr angular resolution. As part of the standard SBS detector package the Gas Ring Imaging Cherenkov (GRINCH) detector will help identify particles produced in the experiments. To determine which photomultiplier (PMT) tubes would be used in GRINCH, more than 900 29 mm 9125B PMTs were tested. Two models, were used to fit test data. For the parameters relevant to this study, results from both models were found to be equivalent, and will be discussed here.

Mini gamma camera, camera system and method of use

DOEpatents

Majewski, Stanislaw; Weisenberger, Andrew G.; Wojcik, Randolph F.

2001-01-01

A gamma camera comprising essentially and in order from the front outer or gamma ray impinging surface: 1) a collimator, 2) a scintillator layer, 3) a light guide, 4) an array of position sensitive, high resolution photomultiplier tubes, and 5) printed circuitry for receipt of the output of the photomultipliers. There is also described, a system wherein the output supplied by the high resolution, position sensitive photomultipiler tubes is communicated to: a) a digitizer and b) a computer where it is processed using advanced image processing techniques and a specific algorithm to calculate the center of gravity of any abnormality observed during imaging, and c) optional image display and telecommunications ports.

Plasma rotation measurement in small tokamaks using an optical spectrometer and a single photomultiplier as detector.

PubMed

Severo, J H F; Nascimento, I C; Kuznetov, Yu K; Tsypin, V S; Galvão, R M O; Tendler, M

2007-04-01

The method for plasma rotation measurement in the tokamak TCABR is reported in this article. During a discharge, an optical spectrometer is used to scan sequentially spectral lines of plasma impurities and spectral lines of a calibration lamp. Knowing the scanning velocity of the diffraction grating of the spectrometer with adequate precision, the Doppler shifts of impurity lines are determined. The photomultiplier output voltage signals are recorded with adequate sampling rate. With this method the residual poloidal and toroidal plasma rotation velocities were determined, assuming that they are the same as those of the impurity ions. The results show reasonable agreement with the neoclassical theory and with results from similar tokamaks.

RADIATION COUNTER

DOEpatents

Goldsworthy, W.W.

1958-02-01

This patent relates to a radiation counter, and more particularly, to a scintillation counter having high uniform sensitivity over a wide area and capable of measuring alpha, beta, and gamma contamination over wide energy ranges, for use in quickly checking the contami-nation of personnel. Several photomultiplier tubes are disposed in parallel relationship with a light tight housing behind a wall of scintillation material. Mounted within the housing with the photomultipliers are circuit means for producing an audible sound for each pulse detected, and a range selector developing a voltage proportional to the repetition rate of the detected pulses and automatically altering its time constant when the voltage reaches a predetermined value, so that manual range adjustment of associated metering means is not required.

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

NASA Astrophysics Data System (ADS)

Bonanno, G.; Marano, D.; Romeo, G.; Garozzo, S.; Grillo, A.; Timpanaro, M. C.; Catalano, O.; Giarrusso, S.; Impiombato, D.; La Rosa, G.; Sottile, G.

2016-01-01

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

Setup of a photomultiplier tube test bench for LHAASO-KM2A

NASA Astrophysics Data System (ADS)

Wang, Xu; Zhang, Zhong-Quan; Tian, Ye; Du, Yan-Yan; Zhao, Xiao; Shen, Fu-Wang; Li, Chang-Yu; Sun, Yan-Sheng; Feng, Cun-Feng

2016-08-01

To fulfill the requirements for testing the photomultiplier tubes (PMTs) of the electromagnetic detector at the Large High Altitude Air Shower Observatory (LHAASO), a multi-functional PMT test bench with a two-dimensional scanning system has been developed. With this 2D scanning system, 16 PMTs can be scanned simultaneously for characteristics tests, including uniformity, cathode transit time difference, single photo-electron spectrum, gain vs. high voltage, linear behavior and dark noise. The programmable hardware and intelligent software of the test bench make it convenient to use and provide reliable results. The test methods are described in detail and primary results are presented. Supported by NSFC (11075096) SDNFS (ZR2011AM007), China

Evaluation of a near-infrared photomultiplier

NASA Technical Reports Server (NTRS)

Evans, W. E.

1978-01-01

A high performance near infrared sensitive photomultiplier tube was procured and evaluated with emphasis on those characteristics affecting its use over the very large amplitude range of signals encountered by an airborne lidar intended for mapping the distribution of stratospheric aerosols. A cathode quantum efficiency of 4.3 percent at 1.06 micrometer wavelength and a background count of less than 10,000 per second were realized. It is recommended that the tube be stored and operated at a temperature near -20 C, or cooler. Performance was found acceptable for the application in both pulse counting and analog modes, but careful design, probably including dynamic gain control, will be required to effectively utilize both modes on the same lidar shot.

Proton Radiography With Timepix Based Time Projection Chambers.

PubMed

Biegun, Aleksandra K; Visser, Jan; Klaver, Tom; Ghazanfari, Nafiseh; van Goethem, Marc-Jan; Koffeman, Els; van Beuzekom, Martin; Brandenburg, Sytze

2016-04-01

The development of a proton radiography system to improve the imaging of patients in proton beam therapy is described. The system comprises gridpix based time projection chambers, which are based on the Timepix chip designed by the Medipix collaboration, for tracking the protons. This type of detector was chosen to have minimal impact on the actual determination of the proton tracks by the tracking detectors. To determine the residual energy of the protons, a BaF 2 crystal with a photomultiplier tube is used. We present data taken in a feasibility experiment with phantoms that represent tissue equivalent materials found in the human body. The obtained experimental results show a good agreement with the performed simulations.

Simulating Silicon Photomultiplier Response to Scintillation Light

PubMed Central

Jha, Abhinav K.; van Dam, Herman T.; Kupinski, Matthew A.; Clarkson, Eric

2015-01-01

The response of a Silicon Photomultiplier (SiPM) to optical signals is affected by many factors including photon-detection efficiency, recovery time, gain, optical crosstalk, afterpulsing, dark count, and detector dead time. Many of these parameters vary with overvoltage and temperature. When used to detect scintillation light, there is a complicated non-linear relationship between the incident light and the response of the SiPM. In this paper, we propose a combined discrete-time discrete-event Monte Carlo (MC) model to simulate SiPM response to scintillation light pulses. Our MC model accounts for all relevant aspects of the SiPM response, some of which were not accounted for in the previous models. We also derive and validate analytic expressions for the single-photoelectron response of the SiPM and the voltage drop across the quenching resistance in the SiPM microcell. These analytic expressions consider the effect of all the circuit elements in the SiPM and accurately simulate the time-variation in overvoltage across the microcells of the SiPM. Consequently, our MC model is able to incorporate the variation of the different SiPM parameters with varying overvoltage. The MC model is compared with measurements on SiPM-based scintillation detectors and with some cases for which the response is known a priori. The model is also used to study the variation in SiPM behavior with SiPM-circuit parameter variations and to predict the response of a SiPM-based detector to various scintillators. PMID:26236040

Liquid argon scintillation read-out with silicon devices

NASA Astrophysics Data System (ADS)

Canci, N.; Cattadori, C.; D'Incecco, M.; Lehnert, B.; Machado, A. A.; Riboldi, S.; Sablone, D.; Segreto, E.; Vignoli, C.

2013-10-01

Silicon photosensors represent a viable alternative to standard photomultipliers in fields such as communications and medical imaging. We explored the interesting possibility of using these sensors in combination with liquid argon (LAr) for astroparticle physics applications such as neutrino, dark matter and double beta decay experiments. In fact, silicon photosensors have detection efficiencies comparable with those of the highest performance PMTs and can be manufactured with high level of radiopurity. In particular within the on-going R&D activity of the SILENT project (Low background and low noise techniques for double beta decay physics funded by ASPERA) a large area SiPM (Silicon PhotoMultiplier - Hamamatsu S11828-3344M - 1.7 cm2 area) has been installed in a LAr scintillation chamber of 0.5 liters volume together with a cryogenic photomultiplier tube (Hamamatsu R11065) used as a reference. The liquid argon chamber has been exposed to many gamma sources of different energies and single photoelectron response and light yield for the SiPM and PMT have been measured and compared. In this contribution the results of the tests, and the ongoing R&D to optimize the SiPM for cryogenic and for ultralow background applications, are reported, as well as the possible application in the GERDA experiment on Double Beta Decay Searches of 76Ge.

Neutron detection with plastic scintillators coupled to solid state photomultiplier detectors

NASA Astrophysics Data System (ADS)

Christian, James F.; Johnson, Erik B.; Fernandez, Daniel E.; Vogel, Samuel; Frank, Rebecca; Stoddard, Graham; Stapels, Christopher; Pereira, Jorge; Zegers, Remco

2017-09-01

The recent reduction of dark current in Silicon Solid-state photomultipliers (SiSSPMs) makes them an attractive alternative to conventional photomultiplier tubes (PMTs) for scintillation detection applications. Nuclear Physics experiments often require large detector volumes made using scintillation materials, which require sensitive photodetectors, such as a PMTs. PMTs add to the size, fragility, and high-voltage requirements as well as distance requirements for experiments using magnetic fields. This work compares RMD's latest detector modules, denoted as the "year 2 prototype", of plastic scintillators that discriminate gamma and high-energy particle events from neutron events using pulse shape discrimination (PSD) coupled to a SiSSPM to the following two detector modules: a similar "year 1 prototype" and a scintillator coupled to a PMT module. It characterizes the noise floor, relative signal-to-noise ratio (SNR), the timing performance, the PSD figure-of-merit (FOM) and the neutron detection efficiency of RMD's detectors. This work also evaluates the scaling of SiSSPM detector modules to accommodate the volumes needed for many Nuclear Physics experiments. The Si SSPM detector module provides a clear advantage in Nuclear Physics experiments that require the following attributes: discrimination of neutron and gamma-ray events, operation in or near strong magnetic fields, and segmentation of the detector.

Spectral analysis of light emitted during the oxidation of lipids and proteins

NASA Astrophysics Data System (ADS)

Turrens, Julio F.; Robinson, Eric; Freeman, Scott; George, Benedict F., III

2003-05-01

Oxidative stress is associated with a variety of pathological processes of clinical relevance. Some of the intermediates generated during the chain reactions associated with oxidation of lipids and proteins are electronically excited and decay emitting photons, which may be detected with the help of sensitive photomultipliers. This technique has been used to monitor oxidative stress in a variety of scenarios including intact organs in vivo or in vitro, and simple models such as proteins and lipids exposed to oxidants. The main drawback of this technique is that the emission of light is extremely weak and it is subjected to substantial interference from spurious sources. In addition, the quantum efficiency of photomultipliers varies with wavelength making it even more difficult to collect reliable data using photomultipliers sensitive to relatively broad spectral ranges. In order to identify the peak emission wavelengths in the visible region, we exposed model systems (proteins, lipids and amino acids) to peroxynitrite and sources of hydroxyl and alcoxyl radicals, analyzing the emission of light with interference filters. The results indicate that the peak emission for most biological models occurs between 450 and 700 nm. The emission at higher wavelengths (lower energy levels) was observed mostly in the presence of less powerful oxidants such as tert-butyl hydroperoxide.

Novel scintillators and silicon photomultipliers for nuclear physics and applications

NASA Astrophysics Data System (ADS)

Jenkins, David

2015-06-01

Until comparatively recently, scintillator detectors were seen as an old-fashioned tool of nuclear physics with more attention being given to areas such as gamma-ray tracking using high-purity germanium detectors. Next-generation scintillator detectors, such as lanthanum bromide, which were developed for the demands of space science and gamma- ray telescopes, are found to have strong applicability to low energy nuclear physics. Their excellent timing resolution makes them very suitable for fast timing measurements and their much improved energy resolution compared to conventional scintillators promises to open up new avenues in nuclear physics research which were presently hard to access. Such "medium-resolution" spectroscopy has broad interest across several areas of contemporary interest such as the study of nuclear giant resonances. In addition to the connections to space science, it is striking that the demands of contemporary medical imaging have strong overlap with those of experimental nuclear physics. An example is the interest in PET-MRI combined imaging which requires putting scintillator detectors in a high magnetic field environment. This has led to strong advances in the area of silicon photomultipliers, a solid-state replacement for photomultiplier tubes, which are insensitive to magnetic fields. Broad application to nuclear physics of this technology may be foreseen.

The proposal of recommendations for the operation of vacuum sewerage

NASA Astrophysics Data System (ADS)

Mazák, J.; Dvorský, T.; Václavík, V.; Zajac, R.; Hluštík, P.

2017-10-01

This article deals with a comparison of vacuum sewerage system and gravity based sewerage system. It also includes the results of the comparison of both of these systems from various cities, and there are measures suggested on the basis of the findings focused on increasing the efficiency and reducing the operational costs of the selected vacuum sewerage system.

Miniature self-contained vacuum compatible electronic imaging microscope

DOEpatents

Naulleau, Patrick P.; Batson, Phillip J.; Denham, Paul E.; Jones, Michael S.

2001-01-01

A vacuum compatible CCD-based microscopic camera with an integrated illuminator. The camera can provide video or still feed from the microscope contained within a vacuum chamber. Activation of an optional integral illuminator can provide light to illuminate the microscope subject. The microscope camera comprises a housing with a objective port, modified objective, beam-splitter, CCD camera, and LED illuminator.

Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms.

PubMed

Pruttivarasin, Thaned; Katori, Hidetoshi

2015-11-01

We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.

Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pruttivarasin, Thaned, E-mail: thaned.pruttivarasin@riken.jp; Katori, Hidetoshi; Innovative Space-Time Project, ERATO, JST, Bunkyo-ku, Tokyo 113-8656

We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.

Fast Photon Monte Carlo for Water Cherenkov Detectors

NASA Astrophysics Data System (ADS)

Latorre, Anthony; Seibert, Stanley

2012-03-01

We present Chroma, a high performance optical photon simulation for large particle physics detectors, such as the water Cerenkov far detector option for LBNE. This software takes advantage of the CUDA parallel computing platform to propagate photons using modern graphics processing units. In a computer model of a 200 kiloton water Cerenkov detector with 29,000 photomultiplier tubes, Chroma can propagate 2.5 million photons per second, around 200 times faster than the same simulation with Geant4. Chroma uses a surface based approach to modeling geometry which offers many benefits over a solid based modelling approach which is used in other simulations like Geant4.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Development and Testing of an ISRU Soil Mechanics Vacuum Test Facility

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie E.; Wilkinson, R. Allen

2014-01-01

For extraterrestrial missions, earth based testing in relevant environments is key to successful hardware development. This is true for both early component level development and system level integration. For In-Situ Resource Utilization (ISRU) on the moon, hardware must interface with the surface material, or regolith, in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, properly conditioned bed of lunar regolith simulant. However, in earth-based granular media, such as lunar regolith simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. A mid-size chamber (3.66 m tall, 1.5 m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64 m deep by 0.914 m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types were used. Data obtained from an electric cone penetrometer can be used to determine strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off-gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5 Torr, regardless of the pump rate. The slow off-gassing of the soil at low pressure lead to long test times; a full week to reach 10(exp -5) Torr. Robotic soil manipulation would enable multiple ISRU hardware test within the same vacuum cycle. The feasibility of a robotically controlled auger and tamper was explored at vacuum conditions.

Convenient mounting method for electrical measurements of thin samples

NASA Technical Reports Server (NTRS)

Matus, L. G.; Summers, R. L.

1986-01-01

A method for mounting thin samples for electrical measurements is described. The technique is based on a vacuum chuck concept in which the vacuum chuck simultaneously holds the sample and established electrical contact. The mounting plate is composed of a glass-ceramic insulating material and the surfaces of the plate and vacuum chuck are polished. The operation of the vacuum chuck is examined. The contacts on the sample and mounting plate, which are sputter-deposited through metal masks, are analyzed. The mounting method was utilized for van der Pauw measurements.

Vacuum extraction failure is associated with a large head circumference.

PubMed

Kabiri, Doron; Lipschuetz, Michal; Cohen, Sarah M; Yagel, Oren; Levitt, Lorinne; Herzberg, Shmuel; Ezra, Yossef; Yagel, Simcha; Amsalem, Hagai

2018-04-24

To determine whether large head circumference increases the risk of vacuum extraction failure. This EMR-based study included all attempted vacuum extractions performed in a tertiary center between January 2010 and June 2015. All term singleton live births were eligible. Cases were divided into four groups: head circumference ≥90th percentile both with birth weight ≥90th percentile and <90th percentile and fetal head circumference <90th percentile with birth weight ≥90th and <90th percentile. Risk of failed vacuum extraction was compared among these groups. Other neonatal and maternal parameters were also evaluated as potential risk factors. Multinomial multivariable regression provided adjusted odds ratio for vacuum extraction failure while controlling for potential confounders. During the study period, 48,007 deliveries met inclusion criteria, of which 3835 had an attempt at vacuum extraction. We identified 215 (5.6%) cases of vacuum extraction failure. The adjusted odds ratios (aOR) for vacuum extraction failure in cases of large fetal head circumference was 2.31 (95%CI, 1.7-3.15, p < .001). Primiparity, prolonged second stage and occipito-posterior presentation were also found to be significant risk factors for failed vacuum extraction. In this study, we found that large head circumference was associated with vacuum extraction failure rather than high birth weight.

Construction and performance of a silicon photomultiplier/extruded scintillator tail-catcher and muon-tracker

NASA Astrophysics Data System (ADS)

Adloff, C.; Blaha, J.; Blaising, J.-J.; Drancourt, C.; Espargilière, A.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Prast, J.; Vouters, G.; Bilki, B.; Francis, K.; Repond, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; Yu, J.; Buanes, T.; Eigen, G.; Mikami, Y.; Watson, N. K.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Benyamna, M.; Cârloganu, C.; Fehr, F.; Gay, P.; Manen, S.; Royer, L.; Blazey, G. C.; Boona, S.; Chakraborty, D.; Dyshkant, A.; Hedin, D.; Lima, J. G. R.; Powell, J.; Rykalin, V.; Scurti, N.; Smith, M.; Tran, N.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; Cornett, U.; David, D.; Dietrich, J.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hermberg, B.; Karstensen, S.; Krivan, F.; Lucaci-Timoce, A.-I.; Lu, S.; Lutz, B.; Marchesini, I.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Vargas-Trevino, A.; Feege, N.; Garutti, E.; Eckert, P.; Kaplan, A.; Schultz-Coulon, H.-Ch; Shen, W.; Stamen, R.; Tadday, A.; Norbeck, E.; Onel, Y.; Wilson, G. W.; Kawagoe, K.; Uozumi, S.; Dauncey, P. D.; Magnan, A.-M.; Bartsch, V.; Wing, M.; Salvatore, F.; Calvo Alamillo, E.; Fouz, M.-C.; Puerta-Pelayo, J.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Soloviev, Y.; Buzhan, P.; Dolgoshein, B.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Smirnov, S.; Frey, A.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Weuste, L.; Bonis, J.; Bouquet, B.; Callier, S.; Cornebise, P.; Doublet, Ph; Dulucq, F.; Faucci Giannelli, M.; Fleury, J.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch; Pöschl, R.; Raux, L.; Seguin-Moreau, N.; Wicek, F.; Anduze, M.; Boudry, V.; Brient, J.-C.; Jeans, D.; Mora de Freitas, P.; Musat, G.; Reinhard, M.; Ruan, M.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Takeshita, T.

2012-04-01

A prototype module for an International Linear Collider (ILC) detector was built, installed, and tested between 2006 and 2009 at CERN and Fermilab as part of the CALICE test beam program, in order to study the possibilities of extending energy sampling behind a hadronic calorimeter and to study the possibilities of providing muon tracking. The ``tail catcher/muon tracker'' (TCMT) is composed of 320 extruded scintillator strips (dimensions 1000 × 50 × 5 mm3) packaged in 16 one-meter square planes interleaved between steel plates. The scintillator strips were read out with wavelength shifting fibers and silicon photomultipliers. The planes were arranged with alternating horizontal and vertical strip orientations. Data were collected for muons and pions in the energy range 6 GeV to 80 GeV. Utilizing data taken in 2006, this paper describes the design and construction of the TCMT, performance characteristics, and a beam-based evaluation of the ability of the TCMT to improve hadronic energy resolution in a prototype ILC detector. For a typical configuration of an ILC detector with a coil situated outside a calorimeter system with a thickness of 5.5 nuclear interaction lengths, a TCMT would improve relative energy resolution by 6-16% for pions between 20 and 80 GeV.

Non-descanned multifocal multiphoton microscopy with a multianode photomultiplier tube

PubMed Central

Cha, Jae Won; Yew, Elijah Y. S.; Kim, Daekeun; Subramanian, Jaichandar; Nedivi, Elly; So, Peter T. C.

2015-01-01

Multifocal multiphoton microscopy (MMM) improves imaging speed over a point scanning approach by parallelizing the excitation process. Early versions of MMM relied on imaging detectors to record emission signals from multiple foci simultaneously. For many turbid biological specimens, the scattering of emission photons results in blurred images and degrades the signal-to-noise ratio (SNR). We have recently demonstrated that a multianode photomultiplier tube (MAPMT) placed in a descanned configuration can effectively collect scattered emission photons from each focus into their corresponding anodes significantly improving image SNR for highly scattering specimens. Unfortunately, a descanned MMM has a longer detection path resulting in substantial emission photon loss. Optical design constraints in a descanned geometry further results in significant optical aberrations especially for large field-of-view (FOV), high NA objectives. Here, we introduce a non-descanned MMM based on MAPMT that substantially overcomes most of these drawbacks. We show that we improve signal efficiency up to fourfold with limited image SNR degradation due to scattered emission photons. The excitation foci can also be spaced wider to cover the full FOV of the objective with minimal aberrations. The performance of this system is demonstrated by imaging interneuron morphological structures deep in the brains of living mice. PMID:25874160

Implementation of the next-generation Gas Cherenkov Detector at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Carrera, J. A.; Herrmann, H. W.; Khater, H. Y.; Carpenter, A. C.; Beeman, B. V.; Hernandez, J. E.; Sitaraman, S.; Lopez, F. E.; Zylstra, A. B.; Griego, J. R.; Kim, Y. H.; Gales, S. A.; Horsfield, C. J.; Milnes, J. S.; Hares, J. D.

2017-08-01

The newest Gas Cherenkov Detector (GCD-3) diagnostic has completed its Phase I commissioning/milestone at the National Ignition Facility (NIF). GCD-3 was fielded for several years at the Omega Laser Facility in its initial configuration, before being moved to the NIF. Installation at the NIF involved optimization of GCD-3 for the higher background environment and designing a new insertion carrier assembly. GCD-3 serves as the initial phase towards the implementation of the "Super GCD" (SGCD) at the NIF. During this phase of development GCD-3 took measurements from a re-entrant well, 3.9 meters from target chamber center (TCC). Plans to insert GCD-3 within 20 cm of TCC with a Target and Diagnostic Manipulator (TANDM) will be discussed. Data was collected using a Photomultiplier Tube (PMT) in combination with a Mach-Zehnder based recording system. These measurements were used to aid in shielding analysis, validate MCNP models, and fuel design efforts for the SGCD. Findings from the initial data will be covered extensively, including an in-depth look into sources of background and possible mitigation strategies. Ongoing development of phase two, the addition of an ultra-high bandwidth Pulse Dilatation Photomultiplier Tube (PD-PMT), will also be presented.

Characterization of a compact LaBr3(Ce) detector with Silicon photomultipliers at high 14 MeV neutron fluxes

NASA Astrophysics Data System (ADS)

Rigamonti, D.; Nocente, M.; Giacomelli, L.; Tardocchi, M.; Angelone, M.; Broslawski, A.; Cazzaniga, C.; Figueiredo, J.; Gorini, G.; Kiptily, V.; Korolczuk, S.; Murari, A.; Pillon, M.; Pilotti, R.; Zychor, I.; Contributors, JET

2017-10-01

A new compact gamma-ray spectrometer based on a Silicon Photo-Multiplier (SiPM) coupled to a LaBr3(Ce) crystal has been developed for the upgrade of the Gamma Camera (GC) of JET, where it must operate in a high intensity neutron/gamma-ray admixed field. The work presents the results of an experiment aimed at characterizing the effect of 14 MeV neutron irradiation on both LaBr3(Ce) and SiPM that compose the full detector. The pulse height spectrum from neutron interactions with the crystal has been measured and is successfully reproduced by MCNP simulations. It is calculated that about 8% of the impinging neutrons leave a detectable signal of which less than < 4% of the events occur in the energy region above 3 MeV, which is of interest for gamma-ray spectroscopy applications. Neutron irradiation also partly degrades the performance of the SiPM and this is mostly manifested as an increase of the dark current versus the neutron fluence. However, it was found that the SiPM can be still operated up to a fluence of 4×1010 n/cm2, which is the highest value we experimentally tested. Implications of these results for GC measurements at JET are discussed.

Highly-Integrated CMOS Interface Circuits for SiPM-Based PET Imaging Systems.

PubMed

Dey, Samrat; Lewellen, Thomas K; Miyaoka, Robert S; Rudell, Jacques C

2012-01-01

Recent developments in the area of Positron Emission Tomography (PET) detectors using Silicon Photomultipliers (SiPMs) have demonstrated the feasibility of higher resolution PET scanners due to a significant reduction in the detector form factor. The increased detector density requires a proportionally larger number of channels to interface the SiPM array with the backend digital signal processing necessary for eventual image reconstruction. This work presents a CMOS ASIC design for signal reducing readout electronics in support of an 8×8 silicon photomultiplier array. The row/column/diagonal summation circuit significantly reduces the number of required channels, reducing the cost of subsequent digitizing electronics. Current amplifiers are used with a single input from each SiPM cathode. This approach helps to reduce the detector loading, while generating all the necessary row, column and diagonal addressing information. In addition, the single current amplifier used in our Pulse-Positioning architecture facilitates the extraction of pulse timing information. Other components under design at present include a current-mode comparator which enables threshold detection for dark noise current reduction, a transimpedance amplifier and a variable output impedance I/O driver which adapts to a wide range of loading conditions between the ASIC and lines with the off-chip Analog-to-Digital Converters (ADCs).

Highly-Integrated CMOS Interface Circuits for SiPM-Based PET Imaging Systems

PubMed Central

Dey, Samrat; Lewellen, Thomas K.; Miyaoka, Robert S.; Rudell, Jacques C.

2013-01-01

Recent developments in the area of Positron Emission Tomography (PET) detectors using Silicon Photomultipliers (SiPMs) have demonstrated the feasibility of higher resolution PET scanners due to a significant reduction in the detector form factor. The increased detector density requires a proportionally larger number of channels to interface the SiPM array with the backend digital signal processing necessary for eventual image reconstruction. This work presents a CMOS ASIC design for signal reducing readout electronics in support of an 8×8 silicon photomultiplier array. The row/column/diagonal summation circuit significantly reduces the number of required channels, reducing the cost of subsequent digitizing electronics. Current amplifiers are used with a single input from each SiPM cathode. This approach helps to reduce the detector loading, while generating all the necessary row, column and diagonal addressing information. In addition, the single current amplifier used in our Pulse-Positioning architecture facilitates the extraction of pulse timing information. Other components under design at present include a current-mode comparator which enables threshold detection for dark noise current reduction, a transimpedance amplifier and a variable output impedance I/O driver which adapts to a wide range of loading conditions between the ASIC and lines with the off-chip Analog-to-Digital Converters (ADCs). PMID:24301987

Status and New Results for the sPHENIX Calorimeter Systems

DOE PAGES

Woody, C.

2017-11-27

Here, the PHENIX Experiment at RHIC is planning a major upgrade that involves building an entirely new spectrometer, sPHENIX, that is based around the former BaBar solenoid magnet which will enable a comprehensive study of jets and heavy quarkonia in relativistic heavy ion collisions. It will include two new calorimeter systems, one electromagnetic and one hadronic, that will cover an acceptance of ±1.1 units in pseudorapidity and 2π in azimuth. The hadronic calorimeter will be a steel plate scintillating tile design that is read out with wavelength shifting fibers and silicon photomultipliers. It will be divided into two sections: onemore » (the Inner HCAL) will be situated inside the magnet and the other (the Outer HCAL) will be outside the magnet. The electromagnetic calorimeter will be a SPACAL design consisting of a tungsten powder epoxy matrix absorber with embedded scintillating fibers which are also read out with silicon photomultipliers. The design of sPHENIX and its calorimeter systems has made considerable progress over the past several years and is described in this paper. Prototypes of all three calorimeters were built and tested in the test beam at Fermilab in April of 2016, and the first preliminary results from this test, along with a comparison to Monte Carlo simulations, are also discussed.« less

Status and New Results for the sPHENIX Calorimeter Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woody, C.

Here, the PHENIX Experiment at RHIC is planning a major upgrade that involves building an entirely new spectrometer, sPHENIX, that is based around the former BaBar solenoid magnet which will enable a comprehensive study of jets and heavy quarkonia in relativistic heavy ion collisions. It will include two new calorimeter systems, one electromagnetic and one hadronic, that will cover an acceptance of ±1.1 units in pseudorapidity and 2π in azimuth. The hadronic calorimeter will be a steel plate scintillating tile design that is read out with wavelength shifting fibers and silicon photomultipliers. It will be divided into two sections: onemore » (the Inner HCAL) will be situated inside the magnet and the other (the Outer HCAL) will be outside the magnet. The electromagnetic calorimeter will be a SPACAL design consisting of a tungsten powder epoxy matrix absorber with embedded scintillating fibers which are also read out with silicon photomultipliers. The design of sPHENIX and its calorimeter systems has made considerable progress over the past several years and is described in this paper. Prototypes of all three calorimeters were built and tested in the test beam at Fermilab in April of 2016, and the first preliminary results from this test, along with a comparison to Monte Carlo simulations, are also discussed.« less

Bioaerosol detection and classification using dual excitation wavelength laser-induced fluorescence

NASA Astrophysics Data System (ADS)

Jonsson, Per; Wästerby, Pär.; Gradmark, Per-Åke; Hedborg, Julia; Larsson, Anders; Landström, Lars

2015-05-01

We present results obtained by a detection system designed to measure laser-induced fluorescence from individual aerosol particles using dual excitation wavelengths. The aerosol is sampled from ambient air and via a 1 mm diameter nozzle, surrounded by a sheath air flow, confined into a particle beam. A continuous wave blue laser at 404 nm is focused on the aerosol beam and two photomultiplier tubes monitor the presence of individual particles by simultaneous measuring the scattered light and any induced fluorescence. When a particle is present in the detection volume, a laser pulse is triggered from an ultraviolet laser at 263 nm and the corresponding fluorescence spectrum is acquired with a spectrometer based on a diffraction grating and a 32 channel photomultiplier tube array with single-photon sensitivity. The spectrometer measures the fluorescence spectra in the wavelength region from 250 to 800 nm. In the present report, data were measured on different monodisperse reference aerosols, simulants of biological warfare agents, and different interference aerosol particles, e.g. pollen. In the analysis of the experimental data, i.e., the time-resolved scattered and fluorescence signals from 404 nm c.w. light excitation and the fluorescence spectra obtained by a pulsed 263 nm laser source, we use multivariate data analysis methods to classify each individual aerosol particle.

The Salinas Airshower Learning And Discovery Project (SALAD)

NASA Astrophysics Data System (ADS)

Hernandez, Victor; Niduaza, Rommel; Ruiz Castruita, Daniel; Knox, Adrian; Ramos, Daniel; Fan, Sewan; Fatuzzo, Laura

2015-04-01

The SALAD project partners community college and high school STEM students in order to develop and investigate cosmic ray detector telescopes and the physical concepts, using a new light sensor technology based on silicon photomultiplier (SiPM) detectors. Replacing the conventional photomultiplier with the SiPM, offers notable advantages in cost and facilitates more in depth, hands-on learning laboratory activities. The students in the SALAD project design, construct and extensively evaluate the SiPM detector modules. These SiPM modules, can be completed in a short time utilizing cost effective components. We describe our research to implement SiPM as read out light detectors for plastic scintillators in a cosmic ray detector telescope for use in high schools. In particular, we describe our work in the design, evaluation and the assembly of (1) a fast preamplifier, (2) a simple coincidence circuit using fast comparators, to discriminate the SiPM noise signal pulses, and (3) a monovibrator circuit to shape the singles plus the AND logic pulses for subsequent processing. To store the singles and coincidence counts data, an Arduino micro-controller with program sketches can be implemented. Results and findings from our work would be described and presented. US Department of Education Title V Grant Award PO31S090007

Researches on Position Detection for Vacuum Switch Electrode

NASA Astrophysics Data System (ADS)

Dong, Huajun; Guo, Yingjie; Li, Jie; Kong, Yihan

2018-03-01

Form and transformation character of vacuum arc is important influencing factor on the vacuum switch performance, and the dynamic separations of electrode is the chief effecting factor on the transformation of vacuum arcs forms. Consequently, how to detect the position of electrode to calculate the separations in the arcs image is of great significance. However, gray level distribution of vacuum arcs image isn’t even, the gray level of burning arcs is high, but the gray level of electrode is low, meanwhile, the forms of vacuum arcs changes sharply, the problems above restrict electrode position detection precisely. In this paper, algorithm of detecting electrode position base on vacuum arcs image was proposed. The digital image processing technology was used in vacuum switch arcs image analysis, the upper edge and lower edge were detected respectively, then linear fitting was done using the result of edge detection, the fitting result was the position of electrode, thus, accurate position detection of electrode was realized. From the experimental results, we can see that: algorithm described in this paper detected upper and lower edge of arcs successfully and the position of electrode was obtained through calculation.

The self-assembled behavior of DNA bases on the interface.

PubMed

Liu, Lei; Xia, Dan; Klausen, Lasse H; Dong, Mingdong

2014-01-27

A successful example of self-assembly in a biological system is that DNA can be an excellent agent to self-assemble into desirable two and three-dimensional nanostructures in a well-ordered manner by specific hydrogen bonding interactions between the DNA bases. The self-assembly of DNA bases have played a significant role in constructing the hierarchical nanostructures. In this review article we will introduce the study of nucleic acid base self-assembly by scanning tunneling microscopy (STM) at vacuum and ambient condition (the liquid/solid interface), respectively. From the ideal condition to a more realistic environment, the self-assembled behaviors of DNA bases are introduced. In a vacuum system, the energetic advantages will dominate the assembly formation of DNA bases, while at ambient condition, more factors such as conformational freedom and the biochemical environment will be considered. Therefore, the assemblies of DNA bases at ambient condition are different from the ones obtained under vacuum. We present the ordered nanostructures formed by DNA bases at both vacuum and ambient condition. To construct and tailor the nanostructure through the interaction between DNA bases, it is important to understand the assembly behavior and features of DNA bases and their derivatives at ambient condition. The utilization of STM offers the advantage of investigating DNA base self-assembly with sub-molecular level resolution at the surface.

The Self-Assembled Behavior of DNA Bases on the Interface

PubMed Central

Liu, Lei; Xia, Dan; Klausen, Lasse H.; Dong, Mingdong

2014-01-01

A successful example of self-assembly in a biological system is that DNA can be an excellent agent to self-assemble into desirable two and three-dimensional nanostructures in a well-ordered manner by specific hydrogen bonding interactions between the DNA bases. The self-assembly of DNA bases have played a significant role in constructing the hierarchical nanostructures. In this review article we will introduce the study of nucleic acid base self-assembly by scanning tunneling microscopy (STM) at vacuum and ambient condition (the liquid/solid interface), respectively. From the ideal condition to a more realistic environment, the self-assembled behaviors of DNA bases are introduced. In a vacuum system, the energetic advantages will dominate the assembly formation of DNA bases, while at ambient condition, more factors such as conformational freedom and the biochemical environment will be considered. Therefore, the assemblies of DNA bases at ambient condition are different from the ones obtained under vacuum. We present the ordered nanostructures formed by DNA bases at both vacuum and ambient condition. To construct and tailor the nanostructure through the interaction between DNA bases, it is important to understand the assembly behavior and features of DNA bases and their derivatives at ambient condition. The utilization of STM offers the advantage of investigating DNA base self-assembly with sub-molecular level resolution at the surface. PMID:24473140

Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.

PubMed

Zhou, Yihui; Wu, Wenbiao; Qiu, Keqiang

2010-11-01

In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining. Copyright © 2010 Elsevier Ltd. All rights reserved.

Thick SS316 materials TIG welding development activities towards advanced fusion reactor vacuum vessel applications

NASA Astrophysics Data System (ADS)

Kumar, B. Ramesh; Gangradey, R.

2012-11-01

Advanced fusion reactors like ITER and up coming Indian DEMO devices are having challenges in terms of their materials design and fabrication procedures. The operation of these devices is having various loads like structural, thermo-mechanical and neutron irradiation effects on major systems like vacuum vessel, divertor, magnets and blanket modules. The concept of double wall vacuum vessel (VV) is proposed in view of protecting of major reactor subsystems like super conducting magnets, diagnostic systems and other critical components from high energy 14 MeV neutrons generated from fusion plasma produced by D-T reactions. The double walled vacuum vessel is used in combination with pressurized water circulation and some special grade borated steel blocks to shield these high energy neutrons effectively. The fabrication of sub components in VV are mainly used with high thickness SS materials in range of 20 mm- 60 mm of various grades based on the required protocols. The structural components of double wall vacuum vessel uses various parts like shields, ribs, shells and diagnostic vacuum ports. These components are to be developed with various welding techniques like TIG welding, Narrow gap TIG welding, Laser welding, Hybrid TIG laser welding, Electron beam welding based on requirement. In the present paper the samples of 20 mm and 40 mm thick SS 316 materials are developed with TIG welding process and their mechanical properties characterization with Tensile, Bend tests and Impact tests are carried out. In addition Vickers hardness tests and microstructural properties of Base metal, Heat Affected Zone (HAZ) and Weld Zone are done. TIG welding application with high thick SS materials in connection with vacuum vessel requirements and involved criticalities towards welding process are highlighted.

A vacuum-sealed miniature X-ray tube based on carbon nanotube field emitters

NASA Astrophysics Data System (ADS)

Heo, Sung Hwan; Kim, Hyun Jin; Ha, Jun Mok; Cho, Sung Oh

2012-05-01

A vacuum-sealed miniature X-ray tube based on a carbon nanotube field-emission electron source has been demonstrated. The diameter of the X-ray tube is 10 mm; the total length of the tube is 50 mm, and no external vacuum pump is required for the operation. The maximum tube voltage reaches up to 70 kV, and the X-ray tube generates intense X-rays with the air kerma strength of 108 Gy·cm2 min-1. In addition, X-rays produced from the miniature X-ray tube have a comparatively uniform spatial dose distribution.

Tensile Properties and Structure of Several Superalloys after Long- Term Exposure to LiF and Vacuum at 1173 K

NASA Astrophysics Data System (ADS)

Whittenberger, J. D.

1995-12-01

The use of the solid- to- liquid phase transformation of LiF to store thermal energy is under consideration for a space- based solar dynamic system. Although advantageous in terms of its energy density, the melting point of this salt (1121K) is beyond the commonly accepted upper- use temperature of 1100 K for chromium- bearing superalloys in vacuum. However, one commercially available nickel- base superalloy (Hastelloy B- 2) is chromium free; unfortunately, because of its high molybdenum content, this alloy can form phases that cause high- temperature embrittlement. To test the suitability of Hastelloy B- 2, it has been exposed to molten LiF, its vapor and vacuum at 1173 K for 2500, 5000, and 10 h. For control, the chromium- containing cobalt- base Haynes alloy 188 and nickel- base Haynes alloy 230 were also exposed to LiF and vacuum at 1173 K for 5000 h. Neither LiF nor vacuum exposures had any significant effect on Hastelloy B- 2 in terms of microstructural surface damage or weight change. Measurement of the post exposure tensile properties of Hastelloy B- 2, nevertheless, revealed low tensile ductility at 1050 K. Such embrittlement and low strength at elevated temperatures appear to preclude the use of Hastelloy B- 2 as a containment material for LiF. Little evidence of significant attack by LiF was seen in either of the chromium- containing superalloys; however, considerable weight loss and near- surface microstructural damage occurred in both alloys exposed to vacuum. Although measurement of the post exposure room-temperature tensile properties of Haynes alloys 188 and 230 revealed no significant loss of strength or ductility, the severe degree of microstructural damage found in unshielded alloys exposed to vacuum indicates that chromium-bearing superalloys might also be unsuitable for prolonged containment of LiF in space above 1100 K. Keywords

PC based graphic display real-time particle beam uniformity

NASA Technical Reports Server (NTRS)

Huebner, M. A.; Malone, C. J.; Smith, L. S.; Soli, G. A.

1989-01-01

A technique has been developed to support the study of the effects of cosmic rays on integrated circuits. The system is designed to determine the particle distribution across the surface of an integrated circuit accurately while the circuit is bombarded by a particle beam. The system uses photomultiplier tubes, an octal discriminator, a computer-controlled NIM quad counter, and an IBM PC. It provides real-time operator feedback for fast beam tuning and monitors momentary fluctuations in the particle beam. The hardware, software, and system performance are described.

Design of an ultrathin cold neutron detector

NASA Astrophysics Data System (ADS)

Osovizky, A.; Pritchard, K.; Yehuda-Zada, Y.; Ziegler, J.; Binkley, E.; Tsai, P.; Thompson, A.; Hadad, N.; Jackson, M.; Hurlbut, C.; Baltic, G. M.; Majkrzak, C. F.; Maliszewskyj, N. C.

2018-06-01

We describe the design and performance of an ultrathin (<2 mm) cold neutron detector consisting of 6LiF:ZnS(Ag) scintillator in which wavelength shifting fibers have been embedded to conduct scintillation photons out of the medium to a silicon photomultiplier photosensor. The counter has a neutron sensitive volume of 12 mm wide × 30 mm high × 1.4 mm deep. Twenty-four 0.5 mm diameter wavelength shifting fibers conduct the scintillation light out of the plane of the detector and are concentrated onto a 3 mm × 3 mm silicon photomultiplier. The detector is demonstrated to possess a neutron detection efficiency of 93% for 3.27 meV neutrons with a gamma ray rejection ratio on the order of 10-7.

Characterization of silicon photomultipliers and validation of the electrical model

NASA Astrophysics Data System (ADS)

Peng, Peng; Qiang, Yi; Ross, Steve; Burr, Kent

2018-04-01

This paper introduces a systematic way to measure most features of the silicon photomultipliers (SiPM). We implement an efficient two-laser procedure to measure the recovery time. Avalanche probability was found to play an important role in explaining the right behavior of the SiPM recovery process. Also, we demonstrate how equivalent circuit parameters measured by optical tests can be used in SPICE modeling to predict details of the time constants relevant to the pulse shape. The SiPM properties measured include breakdown voltage, gain, diode capacitor, quench resistor, quench capacitor, dark count rate, photodetection efficiency, cross-talk and after-pulsing probability, and recovery time. We apply these techniques on the SiPMs from two companies: Hamamatsu and SensL.

Flow structure measurement by beam scan type LDV

NASA Astrophysics Data System (ADS)

Hino, M.; Nadaoka, K.; Kobayashi, T.; Hironaga, K.; Muramoto, T.

1987-05-01

A new type of laser Doppler velocimeter called SLV (Scan-Type Laser-Doppier Velocimeter) which can measure the velocity field almost continuously and simultaneously has been developed and tested. The principle of the apparatus is to traverse the focal point of split laser beams by reflecting them with a rotating polygon mirror or an oscillating mirror which is driven (and controlled) by a stepping motor and to receive the scattered Doppler signals by a photomultiplier by focusing them through a cylindrical lens. The signals from the photomultiplier and the driving pulse of the stepping motor were transmitted to a persona] computer and processed on-line. Experiments on the oscillatory boundary layer, Kármán vortices, and vortex rings were carried out to check the performance.

Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Z. Q.; Chen, Z. J.; Xie, X. F.

2014-11-15

The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic fieldmore » of 200 G.« less

High speed electrostatic photomultiplier tube for the 1.06 micrometer wavelength. Cup and slat dynode chain combined with flat cathode and coax output produces 0.25 nsec rise time

NASA Technical Reports Server (NTRS)

Sparks, S. D.

1973-01-01

The Varian cup and slat dynode chain was modified to have a flat cathode. These modifications were incorporated in an all-electrostatic photomultiplier tube having a rise time of 0.25 n sec. The tube delivered under the contract had a flat S-20 opaque cathode with a useful diameter of 5 mm. The design of the tube is such that a III to V cathode support is mounted in place of the existing cathode substrate. This cathode support is designed to accept a transferred III to V cathode and maintain the cathode surface in the same position as the S-20 photocathode.

The supercontinuum laser as a flexible source for quasi-steady state and time resolved fluorescence studies

NASA Astrophysics Data System (ADS)

Fenske, Roger; Näther, Dirk U.; Dennis, Richard B.; Smith, S. Desmond

2010-02-01

Commercial Fluorescence Lifetime Spectrometers have long suffered from the lack of a simple, compact and relatively inexpensive broad spectral band light source that can be flexibly employed for both quasi-steady state and time resolved measurements (using Time Correlated Single Photon Counting [TCSPC]). This paper reports the integration of an optically pumped photonic crystal fibre, supercontinuum source1 (Fianium model SC400PP) as a light source in Fluorescence Lifetime Spectrometers (Edinburgh Instruments FLS920 and Lifespec II), with single photon counting detectors (micro-channel plate photomultiplier and a near-infrared photomultiplier) covering the UV to NIR range. An innovative method of spectral selection of the supercontinuum source involving wedge interference filters is also discussed.

A study of timing properties of Silicon Photomultipliers

NASA Astrophysics Data System (ADS)

Avella, Paola; De Santo, Antonella; Lohstroh, Annika; Sajjad, Muhammad T.; Sellin, Paul J.

2012-12-01

Silicon Photomultipliers (SiPMs) are solid-state pixelated photodetectors. Lately these sensors have been investigated for Time of Flight Positron Emission Tomography (ToF-PET) applications, where very good coincidence time resolution of the order of hundreds of picoseconds imply spatial resolution of the order of cm in the image reconstruction. The very fast rise time typical of the avalanche discharge improves the time resolution, but can be limited by the readout electronics and the technology used to construct the device. In this work the parameters of the equivalent circuit of the device that directly affect the pulse shape, namely the quenching resistance and capacitance and the diode and parasitic capacitances, were calculated. The mean rise time obtained with different preamplifiers was also measured.

The upgrade of the CMS hadron calorimeter with silicon photomultipliers

DOE PAGES

Strobbe, N.

2017-01-26

The upgrade of the hadron calorimeter of the CMS experiment at the CERN Large Hadron Collider is currently underway. The endcap sections will be upgraded in the winter of 2016–2017 and the barrel sections during the second LHC long shutdown in 2019. The existing photosensors will be replaced with about 16 000 new silicon photomultipliers (SiPMs), resulting in the first large installation of SiPMs in a radiation environment. All associated front-end electronics will also be upgraded. Here, this paper discusses the motivation for the upgrade and provides a description 17 of the new system, including the SiPMs with associated controlmore » electronics and the front-end readout cards.« less

Telephone equipment room, showing channel terminal bank with vacuum tubes. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Telephone equipment room, showing channel terminal bank with vacuum tubes. View to east - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

Effect of Long-Term 1093 K Exposure to Air or Vacuum on the Structure of Several Wrought Superalloys

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.

1993-01-01

Long-term 1093 K heat treatments of three commercial superalloy sheet materials were undertaken in air -IAI and vacuum. With either exposure, significant precipitation of second phases occurred in the Co-base Haynes(R) Alloy 188 (HA 188) and the Ni-base Haynes(R) Alloy 230 (HA 230); however, much less precipitation was found in the exposed Ni-base alloy Inconel(R) 617 (IN 617). Although some grain growth occurred in HA 198, no changes in the grain size of either HA 230 or IN 617 were observed after 22,500 h at temperature. Oxidation during air heat treatments led to weight gain due to the formation of chromia + spinel scales and surface-connected grain boundary pits/oxides in all three superalloys. Both the weight gain and depth of intergranular attack were dependent on the square root of time, which is indicative of diffusion-controlled phenomena. Because many alloy samples had neighbors in close proximity, most vacuum heat treated specimens did not suffer significant loss of volatile elements. However, some exposed samples were subjected to unrestricted vacuum heat treatments, allowing estimates of volatilization to be made. Based on the data for HA 188, the weight loss during 1093 K vacuum exposure was diffusion controlled once the inhibiting effects of surface films on the as-received alloys were broken down.

Effect of Long-Term 1093 K Exposure to Air or Vacuum on the Structure of Several Wrought Superalloys

NASA Astrophysics Data System (ADS)

Whittenberger, J. D.

1993-10-01

Long-term 1093 K heat treatments of three commercial superalloy sheet materials were undertaken in air and vacuum. With either exposure, significant precipitation of second phases occurred in the Co-base Haynes® Alloy 188 (HA 188) and the Ni-base Haynes® Alloy 230 (HA 230); however, much less precipitation was found in the exposed Ni-base alloy Inconel® 617 (IN 617). Although some grain growth occurred in HA 188, no changes in the grain size of either HA 230 or IN 617 were observed after 22,500 h at temperature. Oxidation during air heat treatments led to weight gain due to the formation of chromia + spinel scales and surface-connected grain boundary pits/oxides in all three superalloys. Both the weight gain and depth of intergranular attack were dependent on the square root of time, which is indicative of diffusion-controlled phenomena. Because many alloy samples had neighbors in close proximity, dmost vacuum heat treated specimens did not suffer significant loss of volatile elements. However, some exposed samples were subjected to unrestricted vacuum heat treatments, allowing estimates of volatilization to be made. Based on the data for HA 188, the weight loss during 1093 K vacuum exposure was diffusion controlled once the inhibiting effects of surface films on the as-received alloys were broken down.

Thermal Vacuum Control Systems Options for Test Facilities

NASA Technical Reports Server (NTRS)

Marchetti, John

2008-01-01

This presentation suggests several Thermal Vacuum System (TVAC) control design approach methods for TVAC facilities. Over the past several years many aerospace companies have or are currently upgrading their TVAC testing facilities whether it be by upgrading old equipment or purchasing new. In doing so they are updating vacuum pumping and thermal capabilities of their chambers as well as their control systems. Although control systems are sometimes are considered second to the vacuum or thermal system upgrade process, they should not be taken lightly and must be planned and implemented with the equipment it is to control. Also, emphasis should be placed on how the operators will use the system as well as the requirements of "their" customers. Presented will be various successful methods of TVAC control systems from Programmable Logic Controller (PLC) based to personal computer (PC) based control.

Initiation of vacuum breakdown and failure mechanism of the carbon nanotube during thermal field emission

NASA Astrophysics Data System (ADS)

Dan, Cai; Lie, Liu; Jin-Chuan, Ju; Xue-Long, Zhao; Hong-Yu, Zhou; Xiao, Wang

2016-04-01

The carbon nanotube (CNT)-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method. Project supported by the National Natural Science Foundation of China (Grant Nos. 11305263 and 61401484).

Carbon nanotubes based vacuum gauge

NASA Astrophysics Data System (ADS)

Rudyk, N. N.; Il'in, O. I.; Il'ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.

2017-11-01

We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

Practical quantum random number generator based on measuring the shot noise of vacuum states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen Yong; Zou Hongxin; Tian Liang

2010-06-15

The shot noise of vacuum states is a kind of quantum noise and is totally random. In this paper a nondeterministic random number generation scheme based on measuring the shot noise of vacuum states is presented and experimentally demonstrated. We use a homodyne detector to measure the shot noise of vacuum states. Considering that the frequency bandwidth of our detector is limited, we derive the optimal sampling rate so that sampling points have the least correlation with each other. We also choose a method to extract random numbers from sampling values, and prove that the influence of classical noise canmore » be avoided with this method so that the detector does not have to be shot-noise limited. The random numbers generated with this scheme have passed ent and diehard tests.« less

Delay grid multiplexing: simple time-based multiplexing and readout method for silicon photomultipliers

NASA Astrophysics Data System (ADS)

Won, Jun Yeon; Ko, Guen Bae; Lee, Jae Sung

2016-10-01

In this paper, we propose a fully time-based multiplexing and readout method that uses the principle of the global positioning system. Time-based multiplexing allows simplifying the multiplexing circuits where the only innate traces that connect the signal pins of the silicon photomultiplier (SiPM) channels to the readout channels are used as the multiplexing circuit. Every SiPM channel is connected to the delay grid that consists of the traces on a printed circuit board, and the inherent transit times from each SiPM channel to the readout channels encode the position information uniquely. Thus, the position of each SiPM can be identified using the time difference of arrival (TDOA) measurements. The proposed multiplexing can also allow simplification of the readout circuit using the time-to-digital converter (TDC) implemented in a field-programmable gate array (FPGA), where the time-over-threshold (ToT) is used to extract the energy information after multiplexing. In order to verify the proposed multiplexing method, we built a positron emission tomography (PET) detector that consisted of an array of 4  ×  4 LGSO crystals, each with a dimension of 3  ×  3  ×  20 mm3, and one- to-one coupled SiPM channels. We first employed the waveform sampler as an initial study, and then replaced the waveform sampler with an FPGA-TDC to further simplify the readout circuits. The 16 crystals were clearly resolved using only the time information obtained from the four readout channels. The coincidence resolving times (CRTs) were 382 and 406 ps FWHM when using the waveform sampler and the FPGA-TDC, respectively. The proposed simple multiplexing and readout methods can be useful for time-of-flight (TOF) PET scanners.

Measurement of partial pressures in vacuum technology and vacuum physics

NASA Technical Reports Server (NTRS)

Huber, W. K.

1986-01-01

It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

Large numbers hypothesis. IV - The cosmological constant and quantum physics

NASA Technical Reports Server (NTRS)

Adams, P. J.

1983-01-01

In standard physics quantum field theory is based on a flat vacuum space-time. This quantum field theory predicts a nonzero cosmological constant. Hence the gravitational field equations do not admit a flat vacuum space-time. This dilemma is resolved using the units covariant gravitational field equations. This paper shows that the field equations admit a flat vacuum space-time with nonzero cosmological constant if and only if the canonical LNH is valid. This allows an interpretation of the LNH phenomena in terms of a time-dependent vacuum state. If this is correct then the cosmological constant must be positive.

The Influence of AN Interacting Vacuum Energy on the Gravitational Collapse of a Star Fluid

NASA Astrophysics Data System (ADS)

Campos, M.

2014-02-01

To explain the accelerated expansion of the universe, models with interacting dark components has been considered in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy. However, at the other side of the same coin, the influence of the vacuum energy in the gravitational collapse is a topic of scientific interest. Based in a simple assumption on the collapsed rate of the matter fluid density that is altered by the inclusion of a vacuum energy component that interacts with the matter fluid, we study the final fate of the collapse process.

Stabilities of Dried Suspensions of Influenza Virus Sealed in a Vacuum or Under Different Gases

PubMed Central

Greiff, Donald; Rightsel, Wilton A.

1969-01-01

Suspensions of purified influenza virus, dried to a 1.4% content of residual moisture by sublimation of ice in vacuo, were sealed in a vacuum or under different gases of high purity. The stabilities of the several preparations were determined by an accelerated storage test. Based on the times predicted for the dried preparations stored at different temperatures to lose 1 log of infectivity titer, the order of stabilities in relation to sealing in vacuum or under different gases was as follows: helium > hydrogen > vacuum > argon > nitrogen > oxygen > carbon dioxide. Images PMID:5797938

Measurement of the Circular Dichroism of Electronic Transitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutherland, J.C.

2010-08-11

This chapter describes the measurement of circular dichroism (CD) for absorption due to transitions between two distinct electronic states. This is distinguished from absorption of lower energy photons, which are associated with changes of only the vibrational modes of the absorber and from the absorption of higher energy photons, which may result in ionizations. From the instrumental viewpoint, the chapter describes the measurement of CD that can be recorded using a photomultiplier or avalanche photodiode to quantify the intensity of a light beam, a photoelastic modulator to periodically alter the beam's polarization, and a monochromator located between the light sourcemore » and the modulator. Using either criterion, the focus is on the spectral domain spanning about a decade in wavelength (photon energy) from roughly 1.2 {micro}m (1 eV {approx} 160 zJ) in the near infrared to 120 nm (10 eV {approx} 1.6 aJ) in the vacuum ultraviolet (VUV). In the near infrared, there is overlap between the domain of electronic and purely vibrational transitions, the use of photomultipliers or avalanche photodiodes versus solid state detectors and dispersive versus Fourier-transform spectrometers. There is also some overlap in the VUV with synchrotron beamlines that use arrays of magnets called 'insertion devices' to cause the emitted synchrotron radiation to be elliptically polarized. To my knowledge, no single spectrometer spans this entire spectral domain discussed here, and the vast majority of laboratory instruments come nowhere close to either the upper or lower limit. However, similar analytical approaches and types of instrumentation are employed throughout this spectral domain and thus are logically treated together. The focus in this chapter is on the measurement of CD resulting from the inherent chirality of the absorbing system. Several spectroscopic methods that are closely related in terms of science or instrumentation are treated in other chapters. These include magnetic circular dichroism (MCD), linear dichroism (LD), optical rotary dispersion (ORD), fluorescence detected circular dichroism (FDCD), and circularly polarized luminescence (CPL). A basic CD instrument of the type described here can be configured by temporary alterations of the sample compartment, an additional or repositioned detector and modified electronics to perform many of the important experiments in the visible and UV regions. These include unpolarized absorption and total fluorescence in addition to most of the experiments mentioned above. Except for absorption, such extensions of the basic technology will not be discussed here. Other reviews of instrumentation related to CD have appeared, some containing information complementary to that included here.« less

A vacuum-sealed compact x-ray tube based on focused carbon nanotube field-emission electrons

NASA Astrophysics Data System (ADS)

Jeong, Jin-Woo; Kim, Jae-Woo; Kang, Jun-Tae; Choi, Sungyoul; Ahn, Seungjoon; Song, Yoon-Ho

2013-03-01

We report on a fully vacuum-sealed compact x-ray tube based on focused carbon nanotube (CNT) field-emission electrons for various radiography applications. The specially designed two-step brazing process enabled us to accomplish a good vacuum level for the stable and reliable operation of the x-ray tube without any active vacuum pump. Also, the integrated focusing electrodes in the field-emission electron gun focused electron beams from the CNT emitters onto the anode target effectively, giving a small focal spot of around 0.3 mm with a large current of above 50 mA. The active-current control through the cathode electrode of the x-ray tube led a fast digital modulation of x-ray dose with a low voltage of below 5 V. The fabricated compact x-ray tube showed a stable and reliable operation, indicating good maintenance of a vacuum level of below 5 × 10-6 Torr and the possibility of field-emission x-ray tubes in a stand-alone device without an active pumping system.

Synthesis and Characterization of Thianthrene-Based Polyamides

DTIC Science & Technology

1994-07-15

pyrrolidinone using triphenyl phosphite and pyridine. The fused-ring thianthrene-based polyamides were more soluble than analogous poly(thloether amide)s...pyrrolidinone using triphonyl phosphite and pyridine. The fused-ring thianthrene-based polyamides were more soluble than analogous poly(thloether amide)s...sodium hydroxide, and triphenyl phosphite (TPP) was vacuum distilled. UCI and CaCI2 were dried at 180 OC for 48 hours under vacuum. 4,4’-Oxydianiline

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

NASA Astrophysics Data System (ADS)

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

2016-06-01

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

Development of Fast Measurement System of Neutron Emission Profile Using a Digital Signal Processing Technique in JT-60U

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, M.; Shinohara, K.; Itoga, T.

2008-03-12

Neutron emission profiles are routinely measured in JT-60U Tokamak. Stinbene neuron detectors (SNDs), which combine a Stilbene organic crystal scintillation detector (Stilbene detector) with an analog neutron-gamma pulse shape discrimination (PSD) circuit, have been used to measure neutron flux efficiently. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to {approx}1x 10{sup 5} counts/s due to the dead time of the analog PSD circuit. To overcome this issue, a digital signal processing (DSP) system using a Flash-ADC has been developed. In this system, anode signals from the photomultiplier of the Stilbene detectormore » are fed to the Flash ADC and digitized. Then, the PSD between neutrons and gamma-rays are performed using software. The photomultiplier tube is also modified to suppress and correct gain fluctuation of the photomultiplier. The DSP system has been installed in the center channel of the vertical neutron collimator system in JT-60U and applied to measurements of neutron flux in JT-60U experiments. Neutron flux are successfully measured with count rate up to {approx}1x 10{sup 6} counts/s without the effect of pile up of detected pulses. The performance of the DSP system as a neutron detector is demonstrated.« less

Mechanical properties of haynes alloy 188 after 22,500 hours of exposure to LiF-22CaF2 and vacuum at 1093 K

NASA Astrophysics Data System (ADS)

Whittenberger, J. D.

1994-12-01

As a continuation of a study of a space-based thermal energy storage system centered on a LiF-CaF2 eutectic salt contained by Haynes alloy 188, this Co-base superalloy was subjected to molten salt, its vapor, and vacuum for 22,500 h at 1093 K. Samples from all three exposure conditions were tensile tested between 77 to 1200 K; in addition, vacuum and molten-salt exposed specimens were vacuum creep rupture tested at 1050 K. Comparison of these mechanical properties with those measured for the as-received alloy reveals no evidence for degradation beyond that ascribed to simple thermal aging of Haynes alloy 188. This behavior is identical to the 10,000 h results (Ref 3); hence, Haynes alloy 188 is a suitable containment material for an eutectic LiF-CaF2 thermal energy storage salt.

Space Environmental Effects on Thermal Control Coatings

NASA Technical Reports Server (NTRS)

OBrien, Susan K.; Workman, Gary L.

1997-01-01

The study of long term near ultra-violet (NUV) effects in a vacuum atmosphere, is a crucial element for space applications. NUV radiation causes significant changes in the reflectance of many coatings and types of materials. An ultra high vacuum NUV system was assembled in order to investigate various coatings and materials in this hostile environment. The vacuum is an ion pump that maintains a minimum vacuum in the mid 10(exp -9) range. The system has a base pressure of 10(exp -9) torr and this base pressure is maintained with the ion pump. The NUV exposure was maintained at 2-3 suns which allows accelerated NUV exposure without overheating the samples. The goal of this test was to maintain an intensity of 3.4 x 10(exp -2) Watts/cm(exp 2) which equals 2.9 NUV suns. An NUV sun is defined as 1.16 Watts/cm(exp 2) integrated over wavelength of 200-400 nanometers.

Emission spectra of electron irradiated metal foils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emerson, L. C.; Arakawa, E. T.; Ritchie, R. H.

1963-08-09

Thesis submitted to Univ. of Tennessee by L. C. Emerson. An experimental investigation of the visible and ultraviolet light emitted when a charged particle moves across a boundary between two media with different dielectric properties was carried out. The spectral distributions of the light from evaporated foils of copper, germanium, silver, tin, and antimony bombarded by a 1.5-microamp beam of electrons were measured as a function of electron energy between 25 and 100 kev. The analysis was carried out with a Seya-Namioka vacuum ultraviolet spectrometer, Glan-Foucault prism polarizer, and a quartz- window photomultiplier. Calibration of the optical system with amore » NBS tungsten filament lamp enabled the intensity measurements to be carried out on an absolute basis. The experimental results for light polarized parallel to the plane containing the photon and the electron were compared with the calculated intensity of transftion radiation, and in general the agreement was found to be excellent. The component of the photon intensity polarized perpendicular to this plane was compared with the calculated intensity of the optical portion of the bremsstrahlung spectrum. The predicted dependence on electron energy, photon wavelength, and foil thickness was observed although the measured yield was higher than that predicted by theory. The possibility of contributions from Cherenkov radiation and plasma radiation is also considered, but it is shown that it would be unlikely for these radiations to be observed under the experimental conditions of this study.« less

A vacuum gauge based on an ultracold gas

NASA Astrophysics Data System (ADS)

Makhalov, V. B.; Turlapov, A. V.

2017-06-01

We report the design and application of a primary vacuum gauge based on an ultracold gas of atoms in an optical dipole trap. The pressure is calculated from the confinement time for atoms in the trap. The relationship between pressure and confinement time is established from the first principles owing to elimination of all channels introducing losses, except for knocking out an atom from the trap due to collisions with a residual gas particle. The method requires the knowledge of the gas chemical composition in the vacuum chamber, and, in the absence of this information, the systematic error is less than that of the ionisation sensor.

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stutzman, M L; Adderley, P; Brittian, J

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower partmore » of the UHV range. Measured NEG pump speed is high at pressures above 5×10 -11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.« less

Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions.

PubMed

Bright, Nicholas J; Willson, Terry R; Driscoll, Daniel J; Reddy, Subrayal M; Webb, Roger P; Bleay, Stephen; Ward, Neil I; Kirkby, Karen J; Bailey, Melanie J

2013-07-10

The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. Copyright © 2013. Published by Elsevier Ireland Ltd.

Nonperturbative vacuum polarization effects in two-dimensional supercritical Dirac-Coulomb system I. Vacuum charge density

NASA Astrophysics Data System (ADS)

Davydov, A.; Sveshnikov, K.; Voronina, Yu.

2018-01-01

Based on the original combination of analytical methods, computer algebra tools and numerical calculations, proposed recently in Refs. 1-3, the nonperturbative vacuum polarization effects in the 2+1D supercritical Dirac-Coulomb system with Z > Zcr,1 are explored. Both the vacuum charge density ρV P(r→) and vacuum energy ℰV P are considered. The main result of the work is that in the overcritical region ℰV P turns out to be a rapidly decreasing function ˜-ηeffZ3/R with ηeff > 0 and R being the size of the external Coulomb source. Due to a lot of details of calculation the whole work is divided into two parts I and II. In the present part I, we consider the evaluation and behavior of the vacuum density ρV P, which further is used in part II for evaluation of the vacuum energy, with emphasis on the renormalization, convergence of the partial expansion for ρV P and behavior of the integral induced charge QV P in the overcritical region.

Credit BG. West elevation of Test Stand "D" tower, with ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. West elevation of Test Stand "D" tower, with workshop on left, and tunnel entrance at right. Tower is accessed by exterior steel stairway; the vertical vacuum cell (Dv Cell) is obscured behind large square sunscreen. Below the sunscreen can be seen the end of the horizontal vacuum duct leading from the vacuum cell - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Rayleigh Scattering Diagnostic for Simultaneous Measurements of Dynamic Density and Velocity

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Panda, J.

2000-01-01

A flow diagnostic technique based on the molecular Rayleigh scattering of laser light is used to obtain dynamic density and velocity data in turbulent flows. The technique is based on analyzing the Rayleigh scattered light with a Fabry-Perot interferometer and recording information about the interference pattern with a multiple anode photomultiplier tube (PMT). An artificial neural network is used to process the signals from the PMT to recover the velocity time history, which is then used to calculate the velocity power spectrum. The technique is illustrated using simulated data. The results of an experiment to measure the velocity power spectrum in a low speed (100 rn/sec) flow are also presented.

Gain stabilization control system of the upgraded magnetic proton recoil neutron spectrometer at JET.

PubMed

Sjöstrand, Henrik; Andersson Sundén, E; Conroy, S; Ericsson, G; Gatu Johnson, M; Giacomelli, L; Gorini, G; Hellesen, C; Hjalmarsson, A; Popovichev, S; Ronchi, E; Tardocchi, M; Weiszflog, M

2009-06-01

Burning plasma experiments such as ITER and DEMO require diagnostics capable of withstanding the harsh environment generated by the intense neutron flux and to maintain stable operating conditions for times longer than present day systems. For these reasons, advanced control and monitoring (CM) systems will be necessary for the reliable operation of diagnostics. This paper describes the CM system of the upgraded magnetic proton recoil neutron spectrometer installed at the Joint European Torus focusing in particular on a technique for the stabilization of the gain of the photomultipliers coupled to the neutron detectors. The results presented here show that this technique provides good results over long time scales. The technique is of general interest for all diagnostics that employ scintillators coupled to photomultiplier tubes.

Three dimensional imaging detector employing wavelength-shifting optical fibers

DOEpatents

Worstell, William A.

1997-01-01

A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions.

Three dimensional imaging detector employing wavelength-shifting optical fibers

DOEpatents

Worstell, W.A.

1997-02-04

A novel detector element structure and method for its use is provided. In a preferred embodiment, one or more inorganic scintillating crystals are coupled through wavelength shifting optical fibers (WLSFs) to position sensitive photomultipliers (PS-PMTs). The superior detector configuration in accordance with this invention is designed for an array of applications in high spatial resolution gamma ray sensing with particular application to SPECT, PET and PVI imaging systems. The design provides better position resolution than prior art devices at a lower total cost. By employing wavelength shifting fibers (WLSFs), the sensor configuration of this invention can operate with a significant reduction in the number of photomultipliers and electronics channels, while potentially improving the resolution of the system by allowing three dimensional reconstruction of energy deposition positions. 11 figs.

Pulsed neutron detector

DOEpatents

Robertson, deceased, J. Craig; Rowland, Mark S.

1989-03-21

A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

Random numbers from vacuum fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Yicheng; Kurtsiefer, Christian, E-mail: christian.kurtsiefer@gmail.com; Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543

2016-07-25

We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

A preliminary study on shape recovery speed of a styrene-based shape memory polymer composite actuated by different heating methods

NASA Astrophysics Data System (ADS)

Wu, Xuelian; Zhang, Wuyi; Liu, Yanju; Leng, Jinsong

2007-07-01

Thermally activated shape memory polymers (SMPs) receive increasing attention in recent years. Different from those reported in the literature, in this paper we propose a new approach, i.e., using infrared light, for heating SMPs for shape recovery. We compare this approach with the traditional water bath method in terms of shape recovery speed in bending at both vacuum and no vacuum conditions. The results reveal that the shape recovery speed in infrared heating at vacuum condition is about eight times slower than that by hot water. However, the recovery time is more than doubled if without vacuum.

Additive manufacturing of magnetic shielding and ultra-high vacuum flange for cold atom sensors.

PubMed

Vovrosh, Jamie; Voulazeris, Georgios; Petrov, Plamen G; Zou, Ji; Gaber, Youssef; Benn, Laura; Woolger, David; Attallah, Moataz M; Boyer, Vincent; Bongs, Kai; Holynski, Michael

2018-01-31

Recent advances in the understanding and control of quantum technologies, such as those based on cold atoms, have resulted in devices with extraordinary metrological performance. To realise this potential outside of a lab environment the size, weight and power consumption need to be reduced. Here we demonstrate the use of laser powder bed fusion, an additive manufacturing technique, as a production technique relevant to the manufacture of quantum sensors. As a demonstration we have constructed two key components using additive manufacturing, namely magnetic shielding and vacuum chambers. The initial prototypes for magnetic shields show shielding factors within a factor of 3 of conventional approaches. The vacuum demonstrator device shows that 3D-printed titanium structures are suitable for use as vacuum chambers, with the test system reaching base pressures of 5 ± 0.5 × 10 -10 mbar. These demonstrations show considerable promise for the use of additive manufacturing for cold atom based quantum technologies, in future enabling improved integrated structures, allowing for the reduction in size, weight and assembly complexity.

Signal conditioner circuit for photomultiplier tube

NASA Technical Reports Server (NTRS)

Cellier, A.; Hoover, W. M.

1970-01-01

Miniaturized circuit improves measurement of radiation dose absorbed in a scintillation crystal. The temperature coefficient of the field-effect transistor gate-source voltage in the isolation amplifier can be readily controlled.

Vacuum Radiance-Temperature Standard Facility for Infrared Remote Sensing at NIM

NASA Astrophysics Data System (ADS)

Hao, X. P.; Song, J.; Xu, M.; Sun, J. P.; Gong, L. Y.; Yuan, Z. D.; Lu, X. F.

2018-06-01

As infrared remote sensors are very important parts of Earth observation satellites, they must be calibrated based on the radiance temperature of a blackbody in a vacuum chamber prior to launch. The uncertainty of such temperature is thus an essential component of the sensors' uncertainty. This paper describes the vacuum radiance-temperature standard facility (VRTSF) at the National Institute of Metrology of China, which will serve to calibrate infrared remote sensors on Chinese meteorological satellites. The VRTSF can be used to calibrate vacuum blackbody radiance temperature, including those used to calibrate infrared remote sensors. The components of the VRTSF are described in this paper, including the VMTBB, the LNBB, the FTIR spectrometer, the reduced-background optical system, the vacuum chamber used to calibrate customers' blackbody, the vacuum-pumping system and the liquid-nitrogen-support system. The experimental methods and results are expounded. The uncertainty of the radiance temperature of VMTBB is 0.026 °C at 30 °C over 10 μm.

Evaluation tests of industrial vacuum bearings for space use

NASA Astrophysics Data System (ADS)

Obara, S.; Sasaki, A.; Haraguchi, M.; Imagawa, K.; Nishimura, M.; Kawashima, N.

2001-09-01

Tribological performance of industrial vacuum bearings was experimentally evaluated for space use. The bearings selected for investigation were an 8 mm bore-sized deep-groove ball bearing lubricated with a sputtered MoS2 film and that lubricated with an ion-plated Ag film, commercially delivered from three Japanese domestic bearing-manufacturers. Based on survey results of tribological requirements for the existing satellite mechanisms, four types of bearing tests were defined and conducted: a vacuum test at room temperature, an atmosphere-resistant test, a thermal vacuum test and a vibration test. In addition to these tests, variation in tribological performance of the industrial bearings was also investigated. The results of more than eighty tests demonstrated that the industrial vacuum bearings had sufficient lubrication lives with low frictional torque and their data were reasonably repeatable, indicating very good potentiality for space use.

Digital front end electronics design for the EUSO photon detector

NASA Astrophysics Data System (ADS)

Musico, P.; Pallavicini, M.; Petrolini, A.; Pratolongo, F.

2003-09-01

In this paper we will present the design status of the Digital Front End Electronic system (DFEE), that will be used for the EUSO photon detector. The DFEE is able to count the single photoelectrons coming form the detector for a given time period, store the numbers in a memory buffer and read them out after a trigger, using a serial communication line. Because of space, mass and power consumption constraints, the system will be implemented in an ASIC using a deep submicron technology. The actual design follows the original ideas of the system, though adding several new functionalities. A fully functional prototype chip has been submitted for fabrication in fall 2002. Extensive tests will be performed on it both with bench instrumentations and with the real sensor (the multi anode photomultiplier Hamamatsu R7600-M64), expecting significant results by early Summer 2003. Future work is needed to convert the design into a more robust RAD-hard technology, suitable for space applications and to include in the final die an additional circuit used to optimize the performances at high photons rates: the Analog Front End Electronics (AFEE). Moreover the base board used to house the multi anode photomultipliers is presented: it is the back-bone of the microcell and will be the basic block used to build up the EUSO focal surface.

Design, optimization and characterization of the light concentrators of the single-mirror small size telescopes of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Aguilar, J. A.; Basili, A.; Boccone, V.; Cadoux, F.; Christov, A.; della Volpe, D.; Montaruli, T.; Płatos, Ł.; Rameez, M.

2015-01-01

The focal-plane cameras of γ -ray telescopes frequently use light concentrators in front of the light sensors. The purpose of these concentrators is to increase the effective area of the camera as well as to reduce the stray light coming at large incident angles. These light concentrators are usually based on the Winston cone design. In this contribution we present the design of a hexagonal hollow light concentrator with a lateral profile optimized using a cubic Bézier function to achieve a higher collection efficiency in the angular region of interest. The design presented here is optimized for a Davies-Cotton telescope with a primary mirror of about 4 m in diameter and a focal length of 5.6 m. The described concentrators are part of an innovative camera made up of silicon-photomultiplier sensors, although a similar approach can be used for other sizes of single-mirror telescopes with different camera sensors, including photomultipliers. The challenge of our approach is to achieve a cost-effective design suitable for standard industrial production of both the plastic concentrator substrate and the reflective coating. At the same time we maximize the optical performance. In this paper we also describe the optical set-up to measure the absolute collection efficiency of the light concentrators and demonstrate our good understanding of the measured data using a professional ray-tracing simulation.

Measurement of the secondary electron emission from CVD diamond films using phosphor screen detectors

NASA Astrophysics Data System (ADS)

Vaz, R.; May, P. W.; Fox, N. A.; Harwood, C. J.; Chatterjee, V.; Smith, J. A.; Horsfield, C. J.; Lapington, J. S.; Osbourne, S.

2015-03-01

Diamond-based photomultipliers have the potential to provide a significant improvement over existing devices due to diamond's high secondary electron yield and narrow energy distribution of secondary electrons which improves energy resolution creating extremely fast response times. In this paper we describe an experimental apparatus designed to study secondary electron emission from diamond membranes only 400 nm thick, observed in reflection and transmission configurations. The setup consists of a system of calibrated P22 green phosphor screens acting as radiation converters which are used in combination with photomultiplier tubes to acquire secondary emission yield data from the diamond samples. The superior signal voltage sampling of the phosphor screen setup compared with traditional Faraday Cup detection allows the variation in the secondary electron yield across the sample to be visualised, allowing spatial distributions to be obtained. Preliminary reflection and transmission yield data are presented as a function of primary electron energy for selected CVD diamond films and membranes. Reflection data were also obtained from the same sample set using a Faraday Cup detector setup. In general, the curves for secondary electron yield versus primary energy for both measurement setups were comparable. On average a 15-20% lower signal was recorded on our setup compared to the Faraday Cup, which was attributed to the lower photoluminescent efficiency of the P22 phosphor screens when operated at sub-kilovolt bias voltages.

NE-213-scintillator-based neutron detection system for diagnostic measurements of energy spectra for neutrons having energies greater than or equal to 0.8 MeV created during plasma operations at the Princeton Tokamak Fusion Test Reactor

NASA Astrophysics Data System (ADS)

Dickens, J. K.; Hill, N. W.; Hou, F. S.; McConnell, J. W.; Spencer, R. R.; Tsang, F. Y.

1985-08-01

A system for making diagnostic measurements of the energy spectra of greater than or equal to 0.8-MeV neutrons produced during plasma operations of the Princeton Tokamak Fusion Test Reactor (TFTR) has been fabricated and tested and is presently in operation in the TFTR Test Cell Basement. The system consists of two separate detectors, each made up of cells containing liquid NE-213 scintillator attached permanently to RCA-8850 photomultiplier tubes. Pulses obtained from each photomultiplier system are amplified and electronically analyzed to identify and separate those pulses due to neutron-induced events in the detector from those due to photon-induced events in the detector. Signals from each detector are routed to two separate Analog-to-Digital Converters, and the resulting digitized information, representing: (1) the raw neutron-spectrum data; and (2) the raw photon-spectrum data, are transmited to the CICADA data-acquisition computer system of the TFTR. Software programs have been installed on the CICADA system to analyze the raw data to provide moderate-resolution recreations of the energy spectrum of the neutron and photon fluences incident on the detector during the operation of the TFTR. A complete description of, as well as the operation of, the hardware and software is given in this report.

Evaluation of performance of silicon photomultipliers in lidar applications

NASA Astrophysics Data System (ADS)

Vinogradov, Sergey L.

2017-05-01

Silicon Photomultipliers (SiPMs) are a well-recognized new generation of photon number resolving avalanche photodetectors. Many advantages - a high gain with an ultra-low excess noise of multiplication, multi-pixel architecture, relatively low operating voltage - make SiPMs very competitive in a growing number of applications. Challenging demands of LIDAR applications for a receiver having high sensitivity starting from single photons, superior time-offlight resolution, robustness including surviving at bright light flashes, solid-state compactness and more, are expected to be feasible for the SiPMs. Despite some known drawbacks, namely crosstalk, afterpulsing, dark noise, limited dynamic range, SiPMs are already considered as promising substitutes for conventional APDs and PMTs in LIDAR applications. However, these initial considerations are based on a rather simplified representation of the SiPM as a generic LIDAR receiver described by generic expressions. This study is focused on a comprehensive evaluation of a SiPM potential considering essential features of this new technology, which could affect applicability and performance of SiPMs as LIDAR receivers. Namely, an excess noise due to correlated processes of crosstalk and afterpulsing, are included into account utilizing the well-established framework of analytical probabilistic models. The analysis of SiPM performance in terms of a photon number and time resolution clarifies their competitiveness over conventional APD and PMT and anticipates the development of next SiPM generations.

Photo-multiplier Tube Based Hybrid MRI and Frequency Domain Fluorescence Tomography System for Small Animal Imaging

PubMed Central

Lin, Y; Ghijsen, M T; Gao, H; Liu, N; Nalcioglu, O; Gulsen, G

2014-01-01

Fluorescence tomography (FT) is a promising molecular imaging technique that can spatially resolve both fluorophore concentration and lifetime parameters. However, recovered fluorophore parameters highly depend on the size and depth of the object due to the ill-posedness of the FT inverse problem. Structural a priori information from another high spatial resolution imaging modality has been demonstrated to significantly improve FT reconstruction accuracy. In this study, we have constructed a combined magnetic resonance imaging (MRI) and FT system for small animal imaging. A photo-multiplier tube (PMT) is used as the detector to acquire frequency domain FT measurements. This is the first MR-compatible time-resolved FT system that can reconstruct both fluorescence concentration and lifetime maps simultaneously. The performance of the hybrid system is evaluated with phantom studies. Two different fluorophores, Indocyanine Green (ICG) and 3-3′ Diethylthiatricarbocyanine Iodide (DTTCI), which have similar excitation and emission spectra but different lifetimes, are utilized. The fluorescence concentration and lifetime maps are both reconstructed with and without the structural a priori information obtained from MRI for comparison. We show that the hybrid system can accurately recover both fluorescence intensity and lifetime within 10% error for two 4.2 mm-diameter cylindrical objects embedded in a 38 mm-diameter cylindrical phantom when MRI structural a priori information is utilized. PMID:21753235

ATLAS Tile Calorimeter calibration and monitoring systems

NASA Astrophysics Data System (ADS)

Cortés-González, Arely

2018-01-01

The ATLAS Tile Calorimeter is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes, located in the outer part of the calorimeter. Neutral particles may also produce a signal after interacting with the material and producing charged particles. The readout is segmented into about 5000 cells, each of them being read out by two photomultipliers in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. This comprises Cesium radioactive sources, Laser, charge injection elements and an integrator based readout system. Information from all systems allows to monitor and equalise the calorimeter response at each stage of the signal production, from scintillation light to digitisation. Calibration runs are monitored from a data quality perspective and used as a cross-check for physics runs. The data quality efficiency achieved during 2016 was 98.9%. These calibration and stability of the calorimeter reported here show that the TileCal performance is within the design requirements and has given essential contribution to reconstructed objects and physics results.

Development of a Control System for the Teat-End Vacuum in Individual Quarter Milking Systems

PubMed Central

Ströbel, Ulrich; Rose-Meierhöfer, Sandra; Öz, Hülya; Brunsch, Reiner

2013-01-01

Progress in sensor technique and electronics has led to a decrease in the costs of electronic and sensor components. In modern dairy farms, having udders in good condition, a lower frequency of udder disease and an extended service life of dairy cows will help ensure competitiveness. The objective of this study was to develop a teat-end vacuum control system with individual quarter actor reaction. Based on a review of the literature, this system is assumed to protect the teat tissue. It reduces the mean teat-end vacuum in the maximum vacuum phase (b) to a level of 20 kPa at a flow rate of 0.25 L/min per quarter. At flow rates higher than 1.50 L/min per quarter, the teat-end vacuum can be controlled to a level of 30 kPa, because in this case it is desirable to have a higher vacuum for the transportation of the milk to the receiver. With this system it is possible for the first time to supply the teat end with low vacuum at low flow rates and with higher vacuum at increasing flow rates in a continuous process with a three second reaction-rate on individual quarter level. This system is completely automated. PMID:23765272

Automated Cryocooler Monitor and Control System Software

NASA Technical Reports Server (NTRS)

Britchcliffe, Michael J.; Conroy, Bruce L.; Anderson, Paul E.; Wilson, Ahmad

2011-01-01

This software is used in an automated cryogenic control system developed to monitor and control the operation of small-scale cryocoolers. The system was designed to automate the cryogenically cooled low-noise amplifier system described in "Automated Cryocooler Monitor and Control System" (NPO-47246), NASA Tech Briefs, Vol. 35, No. 5 (May 2011), page 7a. The software contains algorithms necessary to convert non-linear output voltages from the cryogenic diode-type thermometers and vacuum pressure and helium pressure sensors, to temperature and pressure units. The control function algorithms use the monitor data to control the cooler power, vacuum solenoid, vacuum pump, and electrical warm-up heaters. The control algorithms are based on a rule-based system that activates the required device based on the operating mode. The external interface is Web-based. It acts as a Web server, providing pages for monitor, control, and configuration. No client software from the external user is required.

A Lateral Differential Resonant Pressure Microsensor Based on SOI-Glass Wafer-Level Vacuum Packaging.

PubMed

Xie, Bo; Xing, Yonghao; Wang, Yanshuang; Chen, Jian; Chen, Deyong; Wang, Junbo

2015-09-21

This paper presents the fabrication and characterization of a resonant pressure microsensor based on SOI-glass wafer-level vacuum packaging. The SOI-based pressure microsensor consists of a pressure-sensitive diaphragm at the handle layer and two lateral resonators (electrostatic excitation and capacitive detection) on the device layer as a differential setup. The resonators were vacuum packaged with a glass cap using anodic bonding and the wire interconnection was realized using a mask-free electrochemical etching approach by selectively patterning an Au film on highly topographic surfaces. The fabricated resonant pressure microsensor with dual resonators was characterized in a systematic manner, producing a quality factor higher than 10,000 (~6 months), a sensitivity of about 166 Hz/kPa and a reduced nonlinear error of 0.033% F.S. Based on the differential output, the sensitivity was increased to two times and the temperature-caused frequency drift was decreased to 25%.

A Lateral Differential Resonant Pressure Microsensor Based on SOI-Glass Wafer-Level Vacuum Packaging

PubMed Central

Xie, Bo; Xing, Yonghao; Wang, Yanshuang; Chen, Jian; Chen, Deyong; Wang, Junbo

2015-01-01

This paper presents the fabrication and characterization of a resonant pressure microsensor based on SOI-glass wafer-level vacuum packaging. The SOI-based pressure microsensor consists of a pressure-sensitive diaphragm at the handle layer and two lateral resonators (electrostatic excitation and capacitive detection) on the device layer as a differential setup. The resonators were vacuum packaged with a glass cap using anodic bonding and the wire interconnection was realized using a mask-free electrochemical etching approach by selectively patterning an Au film on highly topographic surfaces. The fabricated resonant pressure microsensor with dual resonators was characterized in a systematic manner, producing a quality factor higher than 10,000 (~6 months), a sensitivity of about 166 Hz/kPa and a reduced nonlinear error of 0.033% F.S. Based on the differential output, the sensitivity was increased to two times and the temperature-caused frequency drift was decreased to 25%. PMID:26402679

Laboratory Investigations of Bidirectional Reflectance using the Photomultiplier Tube

NASA Astrophysics Data System (ADS)

Vides, C.; Nelson, R. M.; Boryta, M. D.; Manatt, K. S.

2016-12-01

The precise measurement of the intensity of a light source is fundamental data to observational sciences, such as spacecraft imaging and atomic particle detection. Photomultiplier tubes (PMT) have played an integral role in many diverse areas such as spacecraft remote sensing by indicating the physical properties of regolith on a planetary surface and particulate matter in an atmosphere. PMTs are essential in neutrino observatories by detecting Cherenkov radiation, the photons emitted when a neutrino interacts with a dielectric medium at highly relativistic velocities. The PMT utilizes the core principle of Albert Einstein's photoelectric effect, with the aid of secondary emission to multiply the electrons emitted from a primary photon. Traditionally, PMTs are used to measure the intensity of photons reflected from a surface. We designed a photometer such that we could measure the photoelectron current from two Hamamatsu R928 photomultiplier tubes, as amplified by Keithly 610 electrometers. The results provide insight into the behavior of photoelectrons, how temperature affects PMT output current, and the amplification electronics that form a basis for remote sensing measurements. We performed photometry with a maximum error of 1% by measuring the intensity of a coherent light source. The calibration procedure involved incrementing and decrementing the high voltage in steps of 50V on a high voltage power supply to locate the linear range within the Gaussian curve of light intensity as a function of high voltage to maximize the signal to noise. We have measured how the signal to noise ratio changes when transmittance was reduced and compared the performance of the PMTs. We measured the intensity as a function of polarization angle. We then measured the response change of the PMT as the reflectance of the incident surface changed. The data was reduced and analyzed using MATLAB. We corrected aliasing and fit the mathematical function of the photoelectron current in relation to high voltage and polarization. Our results have established the linear range of a photomultiplier tube. We have also shown how the signal to noise ratio increases as light intensity decreases. With these results, we can constrain the limits in which the PMT is a valuable tool for experimentation in the fields of physics and astronomy.

Thermal conductivity model for powdered materials under vacuum based on experimental studies

NASA Astrophysics Data System (ADS)

Sakatani, N.; Ogawa, K.; Iijima, Y.; Arakawa, M.; Honda, R.; Tanaka, S.

2017-01-01

The thermal conductivity of powdered media is characteristically very low in vacuum, and is effectively dependent on many parameters of their constituent particles and packing structure. Understanding of the heat transfer mechanism within powder layers in vacuum and theoretical modeling of their thermal conductivity are of great importance for several scientific and engineering problems. In this paper, we report the results of systematic thermal conductivity measurements of powdered media of varied particle size, porosity, and temperature under vacuum using glass beads as a model material. Based on the obtained experimental data, we investigated the heat transfer mechanism in powdered media in detail, and constructed a new theoretical thermal conductivity model for the vacuum condition. This model enables an absolute thermal conductivity to be calculated for a powder with the input of a set of powder parameters including particle size, porosity, temperature, and compressional stress or gravity, and vice versa. Our model is expected to be a competent tool for several scientific and engineering fields of study related to powders, such as the thermal infrared observation of air-less planetary bodies, thermal evolution of planetesimals, and performance of thermal insulators and heat storage powders.

Crystal face temperature determination means

DOEpatents

Nason, D.O.; Burger, A.

1994-11-22

An optically transparent furnace having a detection apparatus with a pedestal enclosed in an evacuated ampule for growing a crystal thereon is disclosed. Temperature differential is provided by a source heater, a base heater and a cold finger such that material migrates from a polycrystalline source material to grow the crystal. A quartz halogen lamp projects a collimated beam onto the crystal and a reflected beam is analyzed by a double monochromator and photomultiplier detection spectrometer and the detected peak position in the reflected energy spectrum of the reflected beam is interpreted to determine surface temperature of the crystal. 3 figs.

Fogging in Polyvinyl Toluene Scintillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, Richard J.; Fritz, Brad G.; Hurlbut, Charles

It has been observed that large polyvinyl toluene (PVT)-based gamma ray detectors can suffer internal “fogging” when exposed to outdoor environmental conditions over long periods of time. When observed, this change results in reduced light collection by photomultiplier tubes connected to the PVT. Investigation of the physical cause of these changes has been explored, and a root cause identified. Water penetration into the PVT from hot, high-humidity conditions results in reversible internal water condensation at room temperature, and permanent micro-fracturing of the PVT at very low environmental temperatures. Mitigation procedures and methods are being investigated.

Chemical Analysis through CL-Detection Assisted by Periodate Oxidation

PubMed Central

Evmiridis, Nicholaos P.; Vlessidis, Athanasios G.; Thanasoulias, Nicholas C.

2007-01-01

The progress of the research work of the author and his colleagues on the field of CL-emission generated by pyrogallol oxidation and further application for the direct determination of periodate and indirect or direct determination of other compounds through flow-injection manifold/CL-detection set up is described. The instrumentation used for these studies was a simple flow-injection manifold that provides good reproducibility, coupled to a red sensitive photomultiplier that gives sensitive CL-detection. In addition, recent reports on studies and analytical methods based on CL-emission generated by periodate oxidation by other authors are included. PMID:17611611

Front-end electronics for the LZ experiment

NASA Astrophysics Data System (ADS)

Morad, James; LZ Collaboration

2016-03-01

LZ is a second generation direct dark matter detection experiment with 5.6 tonnes of liquid xenon active target, which will be instrumented as a two-phase time projection chamber (TPC). The peripheral xenon outside the active TPC (``skin'') will also be instrumented. In addition, there will be a liquid scintillator based outer veto surrounding the main cryostat. All of these systems will be read out using photomultiplier tubes. I will present the designs for front-end electronics for all these systems, which have been optimized for shaping times, gains, and low noise. Preliminary results from prototype boards will also be presented.

Characterization of Novel Operation Modes for Secondary Emission Ionization Calorimetry

NASA Astrophysics Data System (ADS)

Tiras, Emrah; Dilsiz, Kamuran; Ogul, Hasan; Snyder, Christina; Bilki, Burak; Onel, Yasar; Winn, David

2017-01-01

Secondary Emission (SE) Ionization Calorimetry is a novel technique to measure electromagnetic showers in high radiation environments. We have developed new operation modes by modifying the bias of the conventional PMT circuits. Hamamatsu single anode R7761 and multi-anode R5900-00-M16 Photomultiplier Tubes (PMTs) with modified bases are used as SE detector modules in our SE calorimetry prototype. In this detector module, the first dynode is used as the active media as opposed to photocathode. Here, we report the technical design of new modes and characterization measurements for both SE and PMT modes.

New fission-fragment detector for experiments at DANCE

NASA Astrophysics Data System (ADS)

Rusev, G.; Roman, A. R.; Daum, J. K.; Springs, R. K.; Bond, E. M.; Jandel, M.; Baramsai, B.; Bredeweg, T. A.; Couture, A.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Ullmann, J. L.; Walker, C. L.

2015-10-01

A fission-fragment detector based on thin scintillating films has been built to serve as a veto/trigger detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing a 4 π detection of the fission fragments. The scintillation events caused by the fission fragment interactions in the films are registered with silicon photomultipliers. Design of the detector and test measurements are described. Work supported by the U.S. Department of Energy through the LANL/LDRD Program and the U.S. Department of Energy, Office of Science, Nuclear Physics under the Early Career Award No. LANL20135009.

Thomson scattering at general fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, W. C., E-mail: william.young@generalfusion.com; Parfeniuk, D.

2016-11-15

This paper provides an overview of the Thomson scattering diagnostic in use at General Fusion, including recent upgrades and upcoming plans. The plasma experiment under examination produces temperatures in the 50-500 eV range with density on the order of 10{sup 20} m{sup −3}. A four spatial point collection optics scheme has been implemented, with plans to expand to six spatial points. Recent changes to the optics of the laser beamline have reduced stray light. The system employs a frequency doubled Nd:YAG laser (532 nm), a grating spectrometer, and a photomultiplier array based detector.

Method for registration of solar cosmic rays by detecting neutrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, A. V.; Mordovskoy, M. V., E-mail: mvmordovsk@mail.ru; Skorkin, V. M.

2016-12-15

We consider a method of detecting the ionizing component of solar cosmic rays (SCRs) with energy from tens of MeV to tens of GeV by measuring the energy loss of SCR protons and light nuclei in scintillators and the multiplicity of the local neutron generation in a converter. Scintillation detectors based on stilbene, lithium glass, and solid-state photomultiplier tubes are capable of detecting fast neutrons with a temporal resolution of 10 ns and rejecting the gamma-ray background in the measuring system. The method will allow investigating the nucleon components of primary SCRs in circumterrestrial space.

Highly multiplexed signal readout for a time-of-flight positron emission tomography detector based on silicon photomultipliers

PubMed Central

Cates, Joshua W.; Bieniosek, Matthew F.; Levin, Craig S.

2017-01-01

Abstract. Maintaining excellent timing resolution in the generation of silicon photomultiplier (SiPM)-based time-of-flight positron emission tomography (TOF-PET) systems requires a large number of high-speed, high-bandwidth electronic channels and components. To minimize the cost and complexity of a system’s back-end architecture and data acquisition, many analog signals are often multiplexed to fewer channels using techniques that encode timing, energy, and position information. With progress in the development SiPMs having lower dark noise, after pulsing, and cross talk along with higher photodetection efficiency, a coincidence timing resolution (CTR) well below 200 ps FWHM is now easily achievable in single pixel, bench-top setups using 20-mm length, lutetium-based inorganic scintillators. However, multiplexing the output of many SiPMs to a single channel will significantly degrade CTR without appropriate signal processing. We test the performance of a PET detector readout concept that multiplexes 16 SiPMs to two channels. One channel provides timing information with fast comparators, and the second channel encodes both position and energy information in a time-over-threshold-based pulse sequence. This multiplexing readout concept was constructed with discrete components to process signals from a 4×4 array of SensL MicroFC-30035 SiPMs coupled to 2.9×2.9×20  mm3 Lu1.8Gd0.2SiO5 (LGSO):Ce (0.025 mol. %) scintillators. This readout method yielded a calibrated, global energy resolution of 15.3% FWHM at 511 keV with a CTR of 198±2  ps FWHM between the 16-pixel multiplexed detector array and a 2.9×2.9×20  mm3 LGSO-SiPM reference detector. In summary, results indicate this multiplexing scheme is a scalable readout technique that provides excellent coincidence timing performance. PMID:28382312

Status of the photomultiplier-based FlashCam camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Pühlhofer, G.; Bauer, C.; Eisenkolb, F.; Florin, D.; Föhr, C.; Gadola, A.; Garrecht, F.; Hermann, G.; Jung, I.; Kalekin, O.; Kalkuhl, C.; Kasperek, J.; Kihm, T.; Koziol, J.; Lahmann, R.; Manalaysay, A.; Marszalek, A.; Rajda, P. J.; Reimer, O.; Romaszkan, W.; Rupinski, M.; Schanz, T.; Schwab, T.; Steiner, S.; Straumann, U.; Tenzer, C.; Vollhardt, A.; Weitzel, Q.; Winiarski, K.; Zietara, K.

2014-07-01

The FlashCam project is preparing a camera prototype around a fully digital FADC-based readout system, for the medium sized telescopes (MST) of the Cherenkov Telescope Array (CTA). The FlashCam design is the first fully digital readout system for Cherenkov cameras, based on commercial FADCs and FPGAs as key components for digitization and triggering, and a high performance camera server as back end. It provides the option to easily implement different types of trigger algorithms as well as digitization and readout scenarios using identical hardware, by simply changing the firmware on the FPGAs. The readout of the front end modules into the camera server is Ethernet-based using standard Ethernet switches and a custom, raw Ethernet protocol. In the current implementation of the system, data transfer and back end processing rates of 3.8 GB/s and 2.4 GB/s have been achieved, respectively. Together with the dead-time-free front end event buffering on the FPGAs, this permits the cameras to operate at trigger rates of up to several ten kHz. In the horizontal architecture of FlashCam, the photon detector plane (PDP), consisting of photon detectors, preamplifiers, high voltage-, control-, and monitoring systems, is a self-contained unit, mechanically detached from the front end modules. It interfaces to the digital readout system via analogue signal transmission. The horizontal integration of FlashCam is expected not only to be more cost efficient, it also allows PDPs with different types of photon detectors to be adapted to the FlashCam readout system. By now, a 144-pixel mini-camera" setup, fully equipped with photomultipliers, PDP electronics, and digitization/ trigger electronics, has been realized and extensively tested. Preparations for a full-scale, 1764 pixel camera mechanics and a cooling system are ongoing. The paper describes the status of the project.

Silicon Photomultipliers for Compact Neutron Scatter Cameras

NASA Astrophysics Data System (ADS)

Ruch, Marc L.

The ability to locate and identify special nuclear material (SNM) is critical for treaty verification and emergency response applications. SNM is used as the nuclear explosive in a nuclear weapon. This material emits neutrons, either spontaneously or when interrogated. The ability to form an image of the neutron source can be used for characterization and/or to confirm that the item is a weapon by determining whether its shape is consistent with that of a weapon. Additionally, treaty verification and emergency response applications might not be conducive to non-portable instruments. In future weapons treaties, for example, it is unlikely that host countries will make great efforts to facilitate large, bulky, and/or fragile inspection equipment. Furthermore, inspectors and especially emergency responders may need to access locations not easily approachable by vehicles. Therefore, there is a considerable need for a compact, human-portable neutron imaging system. Of the currently available neutron imaging technologies, only neutron scatter cameras (NSCs) can be made truly compact because aperture-based imagers, and time-encoded imagers, rely on large amounts of materials to modulate the neutron signal. NSCs, in contrast, can be made very small because most of the volume of the imager can be filled with active detector material. Also, unlike other neutron imaging technologies, NSCs have the inherent ability to act as neutron spectrometers which gives them an additional means of identifying a neutron source. Until recently, NSCs have relied on photomultiplier tubes (PMT) readouts, which are bulky and fragile, require high voltage, and are very sensitive to magnetic fields. Silicon photomultipliers (SiPMs) do not suffer from these drawbacks and are comparable to PMTs in many respects such as gain, and cost with better time resolution. Historically, SiPMs have been too noisy for these applications; however, recent advancements have greatly reduced this issue and they have now been shown to be viable alternatives to PMTs for neutron detection applications. In this thesis, the development of a handheld NSC based on SiPMs coupled to stilbene bars is presented. An algorithm for performing image reconstruction with this type of device is detailed. Prototype design optimization is achieved using a series of simulations and the construction of the optimized prototype is described. The device is calibrated through a series of collimated measurements, backscatter-gated measurements, and a time-of-flight measurement. Experimental imaging and spectroscopic results are presented for a measurement of a Cf-252 spontaneous fission source. Simulated detector response, based on measurements performed with components of the design, demonstrates that fission sources of different sizes would be distinguishable. Notably, a significant quantity of plutonium can be confidently distinguished from a point neutron source.

VOLATILE ORGANO-METALLOIDS IN BIO-SOLID MATERIALS: ANALYSIS BY VACUUM DISTILLATION-GC/MS

EPA Science Inventory

An analytical method based on vacuum distillation-gas chromatography-mass spectrometry (VD-GC-MS)

was developed for determining volatile organo-metalloid contaminants in bio-solid materials. Method

performance was evaluated for dimethylselenide (DMSe), dimethyldisel...

Circuit modification aids in atomic particle discrimination

NASA Technical Reports Server (NTRS)

Blue, J. W.; Shook, D. F.

1970-01-01

Circuit, using a bialkali photomultiplier tube and liquid scintillator, eliminates disadvantages of Owen circuit. It distinguishes between recoil protons /energies of 200 keV/ and Compton electrons /energies of 20 keV/.

A CMOS Time-Resolved Fluorescence Lifetime Analysis Micro-System

PubMed Central

Rae, Bruce R.; Muir, Keith R.; Gong, Zheng; McKendry, Jonathan; Girkin, John M.; Gu, Erdan; Renshaw, David; Dawson, Martin D.; Henderson, Robert K.

2009-01-01

We describe a CMOS-based micro-system for time-resolved fluorescence lifetime analysis. It comprises a 16 × 4 array of single-photon avalanche diodes (SPADs) fabricated in 0.35 μm high-voltage CMOS technology with in-pixel time-gated photon counting circuitry and a second device incorporating an 8 × 8 AlInGaN blue micro-pixellated light-emitting diode (micro-LED) array bump-bonded to an equivalent array of LED drivers realized in a standard low-voltage 0.35 μm CMOS technology, capable of producing excitation pulses with a width of 777 ps (FWHM). This system replaces instrumentation based on lasers, photomultiplier tubes, bulk optics and discrete electronics with a PC-based micro-system. Demonstrator lifetime measurements of colloidal quantum dot and Rhodamine samples are presented. PMID:22291564

Mechanism of vacuum breakdown in radio-frequency accelerating structures

NASA Astrophysics Data System (ADS)

Barengolts, S. A.; Mesyats, V. G.; Oreshkin, V. I.; Oreshkin, E. V.; Khishchenko, K. V.; Uimanov, I. V.; Tsventoukh, M. M.

2018-06-01

It has been investigated whether explosive electron emission may be the initiating mechanism of vacuum breakdown in the accelerating structures of TeV linear electron-positron colliders (Compact Linear Collider). The physical processes involved in a dc vacuum breakdown have been considered, and the relationship between the voltage applied to the diode and the time delay to breakdown has been found. Based on the results obtained, the development of a vacuum breakdown in an rf electric field has been analyzed and the main parameters responsible for the initiation of explosive electron emission have been estimated. The formation of craters on the cathode surface during explosive electron emission has been numerically simulated, and the simulation results are discussed.

Deterministic Impulsive Vacuum Foundations for Quantum-Mechanical Wavefunctions

NASA Astrophysics Data System (ADS)

Valentine, John S.

2013-09-01

By assuming that a fermion de-constitutes immediately at source, that its constituents, as bosons, propagate uniformly as scalar vacuum terms with phase (radial) symmetry, and that fermions are unique solutions for specific phase conditions, we find a model that self-quantizes matter from continuous waves, unifying bosons and fermion ontologies in a single basis, in a constitution-invariant process. Vacuum energy has a wavefunction context, as a mass-energy term that enables wave collapse and increases its amplitude, with gravitational field as the gradient of the flux density. Gravitational and charge-based force effects emerge as statistics without special treatment. Confinement, entanglement, vacuum statistics, forces, and wavefunction terms emerge from the model's deterministic foundations.

Markov Property of the Conformal Field Theory Vacuum and the a Theorem.

PubMed

Casini, Horacio; Testé, Eduardo; Torroba, Gonzalo

2017-06-30

We use strong subadditivity of entanglement entropy, Lorentz invariance, and the Markov property of the vacuum state of a conformal field theory to give new proof of the irreversibility of the renormalization group in d=4 space-time dimensions-the a theorem. This extends the proofs of the c and F theorems in dimensions d=2 and d=3 based on vacuum entanglement entropy, and gives a unified picture of all known irreversibility theorems in relativistic quantum field theory.

Application of Molecular Adsorber Coatings in Chamber A for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.

2017-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test facility called Chamber A. This presentation summarizes the background, fabrication, installation, chemical analysis test results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination. As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test facility called Chamber A. This presentation summarizes the background, fabrication, installation, chemical analysis test results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Portal radiation monitor

DOEpatents

Kruse, Lyle W.

1985-01-01

A portal radiation monitor combines 0.1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.

Portal radiation monitor

DOEpatents

Kruse, L.W.

1982-03-23

A portal radiation monitor combines .1% FAR with high sensitivity to special nuclear material. The monitor utilizes pulse shape discrimination, dynamic compression of the photomultiplier output and scintillators sized to maintain efficiency over the entire portal area.

Measurements of wavelength-dependent double photoelectron emission from single photons in VUV-sensitive photomultiplier tubes

NASA Astrophysics Data System (ADS)

Faham, C. H.; Gehman, V. M.; Currie, A.; Dobi, A.; Sorensen, P.; Gaitskell, R. J.

2015-09-01

Measurements of double photoelectron emission (DPE) probabilities as a function of wavelength are reported for Hamamatsu R8778, R8520, and R11410 VUV-sensitive photomultiplier tubes (PMTs). In DPE, a single photon strikes the PMT photocathode and produces two photoelectrons instead of a single one. It was found that the fraction of detected photons that result in DPE emission is a function of the incident photon wavelength, and manifests itself below ~250 nm. For the xenon scintillation wavelength of 175 nm, a DPE probability of 18-24% was measured depending on the tube and measurement method. This wavelength-dependent single photon response has implications for the energy calibration and photon counting of current and future liquid xenon detectors such as LUX, LZ, XENON100/1T, Panda-X and XMASS.

Photomultiplier circuit including means for rapidly reducing the sensitivity thereof. [and protection from radiation damage

NASA Technical Reports Server (NTRS)

Mcclenahan, J. O. (Inventor)

1974-01-01

A simple, reliable and inexpensive control circuit is described for rapidly reducing the bias voltage across one or more of the dynode stages of a photomultiplier, to substantially decrease its sensitivity to incoming light at those times where excess light intensity might damage the tube. The control circuit comprises a switching device, such as a silicon controlled rectifier (SCR), coupled between a pair of the electrodes in the tube, preferably the cathode and first dynode, or the first and second dynodes, the switching device operating in response to a trigger pulse applied to its gate to short circuit the two electrodes. To insure the desired reduction in sensitivity, two switching stages, the devices be employed between two of the electrode stages, the devices being operated simultaneously to short circuit both stages.

Can the ZoMBieS method be used to characterise scintillator non-linearity?

PubMed

Bignell, L J

2014-05-01

Measurements of the detection efficiency as a function of deposited electron energy in a liquid scintillation cocktail between 4 keV and 49 keV are obtained using the ZoMBieS method. Comparison is made between the measured data and the Poisson-Birks detection efficiency model. Measurements of the Birks non-linearity parameter, kB, and the linearised scintillation response of each photomultiplier, ω(i), were made using these data. However, the value of kB that best linearises the scintillator response is found to vary depending upon which photomultiplier is used in its determination, and the measured kB and ω(i) vary depending on the external source geometry. The cause of this behaviour is unknown. The triple-coincident detection efficiency appears to be unaffected by any systematic errors. © 2013 Published by Elsevier Ltd.

Failure Investigation & Design Optimization of a Photo-Multiplier Tube Assembly Under Thermal Loading

NASA Technical Reports Server (NTRS)

Dahya, Kevin

2004-01-01

Analysis of GLAST ACD Photo-Multiplier Tube (PMT) assembly under thermal loading demonstrates that the glass tube experiences high stresses due to Coefficient of Thermal Expansion mismatch, as well as increased stress due to high stiffness and incompressibility of potting compound. Further investigation shows adverse loading effects due to the magnetic shield, a thin piece of steel wrapped around the PMT. This steel, Mu Metal, contained an overlap region that directly attributed to crack propagation in the outside surface of the tube. Sensitivities to different configurations were studied to reduce the stress and provide a more uniform loading throughout the PMT to ensure mission success. Studies indicate substituting a softer and more compressible potting compound and moving the Mu metal from the glass tube to the outside wall of the aluminum housing yields lower stress.

ANTARES and KM3NeT programs for the supernova neutrino detection

NASA Astrophysics Data System (ADS)

Kulikovskiy, Vladimir

2017-02-01

The currently working ANTARES neutrino telescope has capabilities to detect neutrinos produced in astrophysical transient sources. Neutrino alerts are regularly generated to trigger multi-wavelength observatories. Potential sources include gamma-ray bursts, core-collapse supernovae, and flaring active galactic nuclei. In particular, the neutrino detection together with the multi-wavelength observations may reveal hidden jets in the supernova explosions. Supernovae remnants are currently the most promising acceleration sites of the cosmic rays in our Galaxy. The neutrino emission is expected during the cosmic ray interaction with the surrounding matter. The neutrino telescopes in the Northern hemisphere have excellent visibility to the most of the galactic supernovae remnants. Recent results on the search for point-sources with the ANTARES detector and the prospects for the future KM3NeT detector are presented. Although ANTARES and KM3NeT detectors are mainly designed for high energy neutrino detection, the MeV neutrino signal from the supernova can be identified as a simultaneous increase of the counting rate of the optical modules in the detector. The noise from the optical background due to 40K decay in the sea water and the bioluminescence can be significantly reduced by using nanosecond coincidences between the nearby placed photomultipliers. This technique has been tested with the ANTARES storeys, each one consisting of three 10-inch photomultipliers, and it is further optimized for the KM3NeT telescope where the directional optical modules containing 31 3-inch photomultipliers provide very promising expectations.

Gain Evaluation of Micro-Channel-Plate Photomultipliers in the Upgraded High-B Test Facility at Jefferson Lab

NASA Astrophysics Data System (ADS)

Barber, Corinne; DIRC at EIC Collaboration

2015-10-01

The High-B test facility at Thomas Jefferson National Accelerator Facility allows researchers to evaluate the gain of compact photon sensors, such as Micro-Channel-Plate Photomultipliers (MCP-PMTs), in magnetic fields up to 5 T. These ongoing studies support the development of a Detector of Internally Reflected Cherenkov light (DIRC) to be used in an Electron Ion Collider (EIC). Here, we present our summer 2015 activities to upgrade and improve the facility, and we show results for MCP-PMT gain changes in high B-fields. To monitor the light stability delivered to the MCP-PMTs being tested, we implemented a Silicon Photomultiplier (SiPM) in the setup and calibrated the ADC reading this sensor. A 405-nm Light-Emitting Diode (LED) housed in an optical tube compatible with neutral density filters was also installed. The filters provide an alternative way of reducing the light output of the LED to operate the MCP-PMTs in a single-photon mode. We calibrated a set of filters by means of a photodiode and measured the photon flux at multiple positions relative to the LED. This information helped us to design 3D-printed holders unique to each MCP-PMT so that the photocathode receives the greatest amount of light. The improvements to the setup allow for more precise PMT gain evaluation. This team includes 7 collaborators/co-authors besides myself: Yordanka Ilieva, Kijun Park, Greg Kalicy, Carl Zorn, Pawel Nadel-Turonski, Tongtong Cao, and Lee.

Degassing procedure for ultrahigh vacuum

NASA Technical Reports Server (NTRS)

Moore, B. C.

1979-01-01

Calculations based on diffusion coefficients and degassing rates for stainless-steel vacuum chambers indicate that baking at lower temperatures for longer periods give lower ultimate pressures than rapid baking at high temperatures. Process could reduce pressures in chambers for particle accelerators, fusion reactors, material research, and other applications.

VOLATILE ORGANIC COMPOUND DETERMINATIONS USING SURROGATE-BASED CORRECTION FOR METHOD AND MATRIX EFFECTS

EPA Science Inventory

The principal properties related to analyte recovery in a vacuum distillate are boiling point and relative volatility. The basis for selecting compounds to measure the relationship between these properties and recovery for a vacuum distillation is presented. Surrogates are incorp...

Testing of improved polyimide actuator rod seals at high temperature and under vacuum conditions for use in advanced aircraft hydraulic systems

NASA Technical Reports Server (NTRS)

Sellereite, B. K.; Waterman, A. W.; Nelson, W. G.

1974-01-01

Polyimide second-stage rod seals were evaluated to determine their suitability for applications in space station environments. The 6.35-cm (2.5-in.)K-section seal was verified for thermal cycling operation between room temperature and 478 K (400 F) and for operation in a 133 micron PA(0.000001 mm Hg) vacuum environment. The test seal completed the scheduled 96 thermal cycles and 1438 hr in vacuum with external rod seal leakage well within the maximum allowable of two drops per 25 actuation cycles. At program completion, the seals showed no signs of structural degradation. Posttest inspection showed the seals retained a snug fit against the shaft and housing walls, indicating additional wear life capability. Evaluation of a molecular flow section during vacuum testing, to inhibit fluid loss through vaporization, showed it to be beneficial with MIL-H-5606, a petroleum-base fluid, in comparison with MIL-H-83282, a synthetic hydrocarbon-base fluid.

Quantum Field Energy Sensor based on the Casimir Effect

NASA Astrophysics Data System (ADS)

Ludwig, Thorsten

The Casimir effect converts vacuum fluctuations into a measurable force. Some new energy technologies aim to utilize these vacuum fluctuations in commonly used forms of energy like electricity or mechanical motion. In order to study these energy technologies it is helpful to have sensors for the energy density of vacuum fluctuations. In today's scientific instrumentation and scanning microscope technologies there are several common methods to measure sub-nano Newton forces. While the commercial atomic force microscopes (AFM) mostly work with silicon cantilevers, there are a large number of reports on the use of quartz tuning forks to get high-resolution force measurements or to create new force sensors. Both methods have certain advantages and disadvantages over the other. In this report the two methods are described and compared towards their usability for Casimir force measurements. Furthermore a design for a quantum field energy sensor based on the Casimir force measurement will be described. In addition some general considerations on extracting energy from vacuum fluctuations will be given.

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

NASA Astrophysics Data System (ADS)

Naidu, M. C. A.; Nolakha, Dinesh; Saharkar, B. S.; Kavani, K. M.; Patel, D. R.

2012-11-01

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of "Open loop, auto reversing liquid nitrogen based thermal system". System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

Pseudo ribbon metal ion beam source.

PubMed

Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

2014-02-01

The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

Complex technology of vacuum-arc processing of structural material surface

NASA Astrophysics Data System (ADS)

Arustamov, V. N.; Ashurov, Kh. B.; Kadyrov, Kh. Kh.; Khudoikulov, I. Kh.

2015-08-01

The development of environmentally friendly and energy-resource-saving technologies based on vacuum arc discharge is a topical problem in science and engineering. In view of their unique properties, cathode spots of a vacuum arc induce cleaning of the surface of an article (cathode) from various contaminations and pulsed thermal action on the surface layers. These processes occur in complex with vacuum-arc deposition of coatings in the same technological cycle, which makes it possible to considerably increase the efficiency of methods for changing physical, mechanical, and chemical properties of the surface of steel articles, which considerably increase their service life. Analysis of the formation of the temperature regime of the surface during vacuum arc action and of the parameters of the deposited coating will make it possible to optimize the regimes of complex treatment of the surfaces of articles and is of considerable theoretical and practical importance.

Improvement of an Atomic Clock using Squeezed Vacuum

NASA Astrophysics Data System (ADS)

Kruse, I.; Lange, K.; Peise, J.; Lücke, B.; Pezzè, L.; Arlt, J.; Ertmer, W.; Lisdat, C.; Santos, L.; Smerzi, A.; Klempt, C.

2016-09-01

Since the pioneering work of Ramsey, atom interferometers are employed for precision metrology, in particular to measure time and to realize the second. In a classical interferometer, an ensemble of atoms is prepared in one of the two input states, whereas the second one is left empty. In this case, the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.75 atoms to improve the clock sensitivity of 10000 atoms by 2.05-0.37 +0 .34 dB . The SQL poses a significant limitation for today's microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks based on atomic squeezed vacuum.

Alaskan refiner raced against winter to relocate vacuum unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gdula, L.M.; Wentworth, J.A.

In late November 1994, San Antonio-based Tesoro Petroleum Corp. and Litwin Engineers and Constructors Inc. completed the relocation and refurbishment of a $25 million vacuum unit at Tesoro`s 72,000 b/d Kenai refinery. The addition of the vacuum distillation unit is a critical component in Tesoro`s market-driven strategy to enhance operating profits by maximizing production of higher-margin products such as gasoline and jet fuel. With its new vacuum distillation unit, Tesoro has reduced production of lower-value residual fuel oil while recovering more lighter, high-value material. The paper discusses the economic and strategic merits of purchasing and relocating an existing vacuum unit,more » the project schedule, new equipment, dismantling and transport, installation, tie-ins and start-up, products, operating changes, corrosion concerns, off gas, steam generation, design changes, environmental issues, reporting requirements, and accomplishments.« less

Research on thermal conductivity of HGMs at vacuum in room temperature

NASA Astrophysics Data System (ADS)

Wang, Ping; Liao, Bin; An, Zhenguo; Yan, Kaiqi; Zhang, Jingjie

2018-05-01

Hollow glass microspheres (HGMs) can be used as thermal insulation materials owing to its hollow structure which brings excellent thermal insulation property and low density. At present, most researches on thermal conductivity of HGMs are focused on polymer matrix/HGMs composite materials. However, thermal conductivity of HGMs at vacuum in room temperature has rarely been investigated. In this work, thermal conductivity of six types of HGMs (T17 (0.17g/cm3), T20 (0.20g/cm3), T22 (0.22g/cm3), T25 (0.25g/cm3), T32 (0.32g/cm3) and T40 (0.40g/cm3)) at vacuum in room temperature were calculated by heat transfer of solid conduction and radiation. The calculation results showed that thermal conductivity of HGMs would be decreased by an order of magnitude compared with no vacuum. In order to verify the calculation and study vacuum thermal insulation properties of HGMs, thermal conductivity of above-mentioned HGMs at no vacuum and high vacuum in room temperature were measured by a self-made thermal conductivity measuring apparatus which was based on the transient plane source (TPS) method. The experimental results showed that thermal conductivity of HGMs were in the range of 4.2030E-02 to 6.3300E-02 W/m.K (at no vacuum) and 3.8160E-03 to 4.9660E-03 W/m.K (at high vacuum). The results indicated that experimental thermal conductivity was consistent with the calculation results and both of them were all decreased by 8-13 times at vacuum compared with no vacuum. In addition, the relationship with physical properties and thermal conductivity of HGMs has been discussed in detail. In conclusion, HGMs possess excellent thermal insulation performance at high vacuum in room temperature and have potential to further reduce thermal conductivity at the same conditions.

Development of a Modified Vacuum Cleaner for Lunar Surface Systems

NASA Technical Reports Server (NTRS)

Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

2009-01-01

The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf" vacuum cleaner has been used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating percent removal, relative to the retained simulant on the tested surface. In addition, Scanning Electron Microscopy (SEM) imaging was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has focused on detachment capabilities varying pressure environments.

Development of a Modified Vacuum Cleaner for Lunar Surface Systems

NASA Technical Reports Server (NTRS)

Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

2010-01-01

The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf' vacuum cleaner will be used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques in order to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating particulate removal, relative to the retained simulant on the tested surface. In addition, optical microscopy was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has focused on detachment capabilities at varying pressure environments.

Lunar concrete for construction

NASA Technical Reports Server (NTRS)

Cullingford, Hatice S.; Keller, M. Dean

1988-01-01

Feasibility of using concrete for lunar-base construction has been discussed recently without relevant data for the effects of vacuum on concrete. Experimental studies performed earlier at Los Alamos have shown that concrete is stable in vacuum with no deterioration of its quality as measured by the compressive strength. Various considerations of using concrete successfully on the moon are provided in this paper along with specific conclusions from the existing data base.

Development of a modified dry curing process for beef.

PubMed

Hayes, J E; Kenny, T A; Ward, P; Kerry, J P

2007-11-01

The development of a dry curing process using physical treatments to promote the diffusion of the cure ingredients was studied. Vacuum pulsing with and without tumbling, continuous vacuum, and tumbling only treatments were compared with a conventional static dry cure control method on beef M. supraspinatus. Vacuum tumble and tumble only treatments gave highest core salt content after 7 days conditioning (3.3% and 3.1%, respectively). All test treatments resulted in higher colour uniformity and lower % cook loss in comparison to control (P<0.001). The control and vacuum pulsed samples were tougher (P<0.001). Vacuum tumble and tumble only treatments gave higher acceptability (P<0.001). Based on these findings for M. supraspinatus, indicating that the vacuum tumble treatments gave the best results, further testing of this method was conducted using the M. biceps femoris in addition to the M. supraspinatus. Cured beef slices were stored in modified atmosphere packs (MAP) (80%N(2):20%CO(2)) for up to 28 day at 4°C. Redness (a(∗), P<0.001) decreased over storage time in M. biceps femoris. Vacuum tumble treatment increased (P<0.05) redness in M. supraspinatus. Results obtained demonstrate the benefits of vacuum tumbling over the other physical treatments as a method for accelerating the dry curing process, producing dry cured beef products with enhanced organoleptic quality and increased yields.

The MEMS Knudsen Compressor as a Vacuum Pump for Space Exploration Applications

NASA Technical Reports Server (NTRS)

Vargo, S. E.; Muntz, E. P.; Tang, W. C.

2000-01-01

Several lander, probe and rover missions currently under study at the Jet Propulsion Laboratory (JPL) and especially in the Microdevices Laboratory (MDL) Center for Space Microelectronics Technology, focus on utilizing microelectromechanical systems (MEMS) based instruments for science data gathering. These small instruments and NASA's commitment to "faster, better, cheaper" type missions has brought about the need for novel approaches to satisfying mission requirements. Existing in-situ instrument systems clearly lack novel and integrated methods for satisfying their vacuum needs. One attractive candidate for a MEMS vacuum pump is the Knudsen Compressor, which operates based on thermal transpiration. Thermal transpiration describes gas flows induced by temperature differences maintained across orifices, porous membranes or capillary tubes under rarefied conditions. This device has two overwhelmingly attractive features as a MEMS vacuum pump - no moving parts and no fluids. An initial estimate of a Knudsen Compressor's pumping power requirements for a surface atmospheric sampling task on Mars is less than 80 mW, significantly below than alternative pumps. Due to the relatively low energy use for this task and the applicability of the Knudsen Compressor to other applications, the development of a Knudsen Compressor utilizing MEMS fabrication techniques has been initiated. This paper discusses the initial fabrication of a single-stage MEMS Knudsen Compressor vacuum pump, provides performance criteria such as pumping speed, size, energy use and ultimate pressure and details vacuum pump applications in several MDL related in-situ instruments.

Overview of field gamma spectrometries based on Si-photomultiplier

NASA Astrophysics Data System (ADS)

Denisov, Viktor; Korotaev, Valery; Titov, Aleksandr; Blokhina, Anastasia; Kleshchenok, Maksim

2017-05-01

Design of optical-electronic devices and systems involves the selection of such technical patterns that under given initial requirements and conditions are optimal according to certain criteria. The original characteristic of the OES for any purpose, defining its most important feature ability is a threshold detection. Based on this property, will be achieved the required functional quality of the device or system. Therefore, the original criteria and optimization methods have to subordinate to the idea of a better detectability. Generally reduces to the problem of optimal selection of the expected (predetermined) signals in the predetermined observation conditions. Thus the main purpose of optimization of the system when calculating its detectability is the choice of circuits and components that provide the most effective selection of a target.

A SiPM based real time dosimeter for radiotherapic beams

NASA Astrophysics Data System (ADS)

Berra, A.; Conti, V.; Lietti, D.; Milan, L.; Novati, C.; Ostinelli, A.; Prest, M.; Romanó, C.; Vallazza, E.

2015-02-01

This paper describes the development of a scintillator dosimeter prototype for radiotherapic applications based on plastic scintillating fibers readout by Silicon PhotoMultipliers. The dosimeter, whose probes are water equivalent, could be used for quality control measurements, beam characterization and in vivo dosimetry, allowing a real time measurement of the dose spatial distribution. This paper describes the preliminary percentual depth dose scan performed with clinical 6 and 18 MV photon beams, comparing the results with a reference curve. The measurements were performed using a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT). The prototype has given promising results, allowing real time measurements of relative dose without applying any correction factors.

The CBM RICH project

NASA Astrophysics Data System (ADS)

Adamczewski-Musch, J.; Akishin, P.; Becker, K.-H.; Belogurov, S.; Bendarouach, J.; Boldyreva, N.; Chernogorov, A.; Deveaux, C.; Dobyrn, V.; Dürr, M.; Eschke, J.; Förtsch, J.; Heep, J.; Höhne, C.; Kampert, K.-H.; Kochenda, L.; Kopfer, J.; Kravtsov, P.; Kres, I.; Lebedev, S.; Lebedeva, E.; Leonova, E.; Linev, S.; Mahmoud, T.; Michel, J.; Miftakhov, N.; Niebur, W.; Ovcharenko, E.; Patel, V.; Pauly, C.; Pfeifer, D.; Querchfeld, S.; Rautenberg, J.; Reinecke, S.; Riabov, Y.; Roshchin, E.; Samsonov, V.; Tarasenkova, O.; Traxler, M.; Ugur, C.; Vznuzdaev, E.; Vznuzdaev, M.

2017-02-01

The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. The RICH design is based on CO2 gas as radiator, a segmented spherical glass focussing mirror with Al+MgF2 reflective coating, and Multianode Photomultipliers for efficient Cherenkov photon detection. Hamamatsu H12700 MAPMTs have recently been selected as photon sensors, following an extensive sensor evaluation, including irradiation tests to ensure sufficient radiation hardness of the MAPMTs. A brief overview of the detector design and concept is given, results on the radiation hardness of the photon sensors are shown, and the development of a FPGA-TDC based readout chain is discussed.

Pneumatic vacuum tube message center, basement room 23, looking southeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Pneumatic vacuum tube message center, basement room 23, looking southeast toward doorway and corridor. Note soundproof walls, pedestal flooring, and cable tray suspended from the ceiling - March Air Force Base, Strategic Air Command, Combat Operations Center, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

Quantum cryptography using single-particle entanglement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Jae-Weon; Lee, Eok Kyun; Chung, Yong Wook

2003-07-01

A quantum cryptography scheme based on entanglement between a single-particle state and a vacuum state is proposed. The scheme utilizes linear optics devices to detect the superposition of the vacuum and single-particle states. Existence of an eavesdropper can be detected by using a variant of Bell's inequality.

Effects of vacuum and ageing on Zr4/Cr3 based conversion coatings on aluminium alloys

NASA Astrophysics Data System (ADS)

Thirupathi, Kalaivanan; Bárczy, Pál; Vad, Kálmán; Csik, Attila; Somosvári, Béla Márton

2018-05-01

In this study, we investigate the impact of ageing and high vacuum on existing environmentally friendly Zr4/Cr3-based conversion coatings. The freshly formed coating undergoes several changes during ageing and exposure to high vacuum. Based on the present data, we propose that the coating formed over AA6082 and AA7075 alloys is sol-gel in nature, confirmed by secondary neutral mass spectroscopy (SNMS) using the depth profiling technique. Our findings reveal that there are elemental level changes that result in shrinkage of the coating. Most Zr ions in the coating are in the solute form, with lesser number of Cr and Al ions that disappear under high vacuum over a certain period of time. The remaining Cr, Zr and O atoms exist in a gelatinous state. During ageing, there is a continuous transition of ions from solute to gelatinous state. In addition, the deposition of coating ions is directly influenced by the substrates and their constituents. The extent of dissolution of aluminium in the conversion bath determines both Zr and Cr ion deposition. For a highly alloyed metal like AA7075, the dissolution rate is disturbed by copper and zinc.

320 x 240 uncooled IRFPA with pixel wise thin film vacuum packaging

NASA Astrophysics Data System (ADS)

Yon, J.-J.; Dumont, G.; Rabaud, W.; Becker, S.; Carle, L.; Goudon, V.; Vialle, C.; Hamelin, A.; Arnaud, A.

2012-10-01

Silicon based vacuum packaging is a key enabling technology for achieving affordable uncooled Infrared Focal Plane Arrays (IRFPA) as required by the promising mass market for very low cost IR applications, such as automotive driving assistance, energy loss monitoring in buildings, motion sensors… Among the various approaches studied worldwide, the CEA, LETI is developing a unique technology where each bolometer pixel is sealed under vacuum at the wafer level, using an IR transparent thin film deposition. This technology referred to as PLP (Pixel Level Packaging), leads to an array of hermetic micro-caps each containing a single microbolometer. Since the successful demonstration that the PLP technology, when applied on a single microbolometer pixel, can provide the required vacuum < 10-3 mbar, the authors have pushed forward the development of the technology on fully operational QVGA readout circuits CMOS base wafers (320 x 240 pixels). In this outlook, the article reports on the electro optical performance obtained from this preliminary PLP based QVGA demonstrator. Apart from the response, noise and NETD distributions, the paper also puts emphasis on additional key features such as thermal time constant, image quality, and ageing properties.

Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2014-01-01

The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

Effect of osmotic dehydration and vacuum-frying parameters to produce high-quality mango chips.

PubMed

Nunes, Yolanda; Moreira, Rosana G

2009-09-01

Mango (Mangifera indica L.) is a fruit rich in flavor and nutritional values, which is an excellent candidate for producing chips. The objective of this study was to develop high-quality mango chips using vacuum frying. Mango ("Tommy Atkins") slices were pretreated with different maltodextrin concentrations (40, 50, and 65, w/v), osmotic dehydration times (45, 60, and 70 min), and solution temperatures (22 and 40 degrees C). Pretreated slices were vacuum fried at 120, 130, and 138 degrees C and product quality attributes (oil content, texture, color, carotenoid content) determined. The effect of frying temperatures at optimum osmotic dehydration times (65 [w/v] at 40 degrees C) was assessed. All samples were acceptable (scores > 5) to consumer panelists. The best mango chips were those pretreated with 65 (w/v) concentration for 60 min and vacuum fried at 120 degrees C. Mango chips under atmospheric frying had less carotenoid retention (32%) than those under vacuum frying (up to 65%). These results may help further optimize vacuum-frying processing of high-quality fruit-based snacks.

Development of the new trigger for VANDLE neutron detector

NASA Astrophysics Data System (ADS)

Hasse, Adam; Taylor, Steven; Daugherty, Hadyn; Grzywacz, Robert

2014-09-01

Beta-delayed neutron emission (βn) is the dominant decay channel for the majority of very neutron-rich nuclei. In order to study these decays a new detector system called the Versatile Array of Neutron Detectors at Low Energy (VANDLE) was constructed. A critical part of this neutron time of flight detector is a trigger unit. This trigger is sensitive to electron from beta decay down to very low energies, insensitive to gamma rays and have a good timing performance, better than 1 ns. In order to satisfy these condition, we have developed a new system, which utilizes plastic scintillator but uses recently developed light readout technique, based on the so called Silicon Photomultiplier, manufactured by Sensl. New system has been developed and performance tested using digital data acquisition system at the University of Tennessee and will be utilized in future experiments involving VANDLE. Beta-delayed neutron emission (βn) is the dominant decay channel for the majority of very neutron-rich nuclei. In order to study these decays a new detector system called the Versatile Array of Neutron Detectors at Low Energy (VANDLE) was constructed. A critical part of this neutron time of flight detector is a trigger unit. This trigger is sensitive to electron from beta decay down to very low energies, insensitive to gamma rays and have a good timing performance, better than 1 ns. In order to satisfy these condition, we have developed a new system, which utilizes plastic scintillator but uses recently developed light readout technique, based on the so called Silicon Photomultiplier, manufactured by Sensl. New system has been developed and performance tested using digital data acquisition system at the University of Tennessee and will be utilized in future experiments involving VANDLE. Department of Physics and Astronomy, University of Tennessee, Knoxville, USA.

Opticks : GPU Optical Photon Simulation for Particle Physics using NVIDIA® OptiX™

NASA Astrophysics Data System (ADS)

C, Blyth Simon

2017-10-01

Opticks is an open source project that integrates the NVIDIA OptiX GPU ray tracing engine with Geant4 toolkit based simulations. Massive parallelism brings drastic performance improvements with optical photon simulation speedup expected to exceed 1000 times Geant4 when using workstation GPUs. Optical photon simulation time becomes effectively zero compared to the rest of the simulation. Optical photons from scintillation and Cherenkov processes are allocated, generated and propagated entirely on the GPU, minimizing transfer overheads and allowing CPU memory usage to be restricted to optical photons that hit photomultiplier tubes or other photon detectors. Collecting hits into standard Geant4 hit collections then allows the rest of the simulation chain to proceed unmodified. Optical physics processes of scattering, absorption, scintillator reemission and boundary processes are implemented in CUDA OptiX programs based on the Geant4 implementations. Wavelength dependent material and surface properties as well as inverse cumulative distribution functions for reemission are interleaved into GPU textures providing fast interpolated property lookup or wavelength generation. Geometry is provided to OptiX in the form of CUDA programs that return bounding boxes for each primitive and ray geometry intersection positions. Some critical parts of the geometry such as photomultiplier tubes have been implemented analytically with the remainder being tessellated. OptiX handles the creation and application of a choice of acceleration structures such as boundary volume hierarchies and the transparent use of multiple GPUs. OptiX supports interoperation with OpenGL and CUDA Thrust that has enabled unprecedented visualisations of photon propagations to be developed using OpenGL geometry shaders to provide interactive time scrubbing and CUDA Thrust photon indexing to enable interactive history selection.

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

NASA Astrophysics Data System (ADS)

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.

System selects framing rate for spectrograph camera

NASA Technical Reports Server (NTRS)

1965-01-01

Circuit using zero-order light is reflected to a photomultiplier in the incoming radiation of a spectrograph monitor to provide an error signal which controls the advancing and driving rate of the film through the camera.

Study on vacuum packaging reliability of micromachined quartz tuning fork gyroscopes

NASA Astrophysics Data System (ADS)

Fan, Maoyan; Zhang, Lifang

2017-09-01

Packaging technology of the micromachined quartz tuning fork gyroscopes by vacuum welding has been experimentally studied. The performance of quartz tuning fork is influenced by the encapsulation shell, encapsulation method and fixation of forks. Alloy solder thick film is widely used in the package to avoid the damage of the chip structure by the heat resistance and hot temperature, and this can improve the device performance and welding reliability. The results show that the bases and the lids plated with gold and nickel can significantly improve the airtightness and reliability of the vacuum package. Vacuum packaging is an effective method to reduce the vibration damping, improve the quality factor and further enhance the performance. The threshold can be improved nearly by 10 times.

Carbon nanotube vacuum gauges utilizing long, dissipative tubes

NASA Astrophysics Data System (ADS)

Kaul, Anupama B.; Manohara, Harish M.

2008-04-01

A carbon nanotube-based thermal conductivity vacuum gauge is described which utilizes 5-10 μm long diffusively contacted SWNTs for vacuum sensing. By etching the thermal SiO II beneath the tubes and minimizing heat conduction through the substrate, pressure sensitivity was extended toward higher vacuums. The pressure response of unannealed and annealed devices was compared to that of released devices. The released devices showed sensitivity to pressure as low as 1 x 10 -6 Torr. The sensitivity increased more dramatically with power for the released device compared to that of the unreleased device. Low temperature electronic transport measurements of the tubes were suggestive of a thermally activated hopping mechanism where the activation energy for hopping was calculated to be ~ 39 meV.

Vacuum microelectronics for beam power and rectennas

NASA Technical Reports Server (NTRS)

Gray, Henry F.

1989-01-01

Vacuum Microelectronic devices can be described as vacuum transistors or micro-miniature vacuum tubes, as one chooses. The fundamental reason behind this new technology is the very large current densities available from field emitters, namely as high as 10(8) A/sq cm. Array current densities as high as 1000 A/sq cm have been measured. Total electron transit times from source to drain for 1 micron feature size devices have been predicted to be about 150fs. This very short transit time implies the possibility of submillimeter wave transmitters and rectennas in devices which can operate with reasonably high voltages and which are small in size and are lightweight. In addition, they are expected to be extremely radiation hard and very temperature insensitive. That is, they are expected to have radiation hardness characteristics similar to vacuum tubes, and both the high temperature and low temperature limits should be determined by the package. That is, there should be no practical intrinsic temperature or carrier freezeout problems for devices based on metals or composites. But the technology is difficult to implement at the present time because it is based on 300 to 500 angstrom radius field emitters which must be relatively uniform. There is also the need to understand the non-equilibrium transport physics in the near-surface regions of the field emitters.

Design verification of large time constant thermal shields for optical reference cavities.

PubMed

Zhang, J; Wu, W; Shi, X H; Zeng, X Y; Deng, K; Lu, Z H

2016-02-01

In order to achieve high frequency stability in ultra-stable lasers, the Fabry-Pérot reference cavities shall be put inside vacuum chambers with large thermal time constants to reduce the sensitivity to external temperature fluctuations. Currently, the determination of thermal time constants of vacuum chambers is based either on theoretical calculation or time-consuming experiments. The first method can only apply to simple system, while the second method will take a lot of time to try out different designs. To overcome these limitations, we present thermal time constant simulation using finite element analysis (FEA) based on complete vacuum chamber models and verify the results with measured time constants. We measure the thermal time constants using ultrastable laser systems and a frequency comb. The thermal expansion coefficients of optical reference cavities are precisely measured to reduce the measurement error of time constants. The simulation results and the experimental results agree very well. With this knowledge, we simulate several simplified design models using FEA to obtain larger vacuum thermal time constants at room temperature, taking into account vacuum pressure, shielding layers, and support structure. We adopt the Taguchi method for shielding layer optimization and demonstrate that layer material and layer number dominate the contributions to the thermal time constant, compared with layer thickness and layer spacing.

Optical binding of two microparticles levitated in vacuum

NASA Astrophysics Data System (ADS)

Arita, Yoshihiko; Wright, Ewan M.; Dholakia, Kishan

2017-04-01

Optical binding refers to an optically mediated inter-particle interaction that creates new equilibrium positions for closely spaced particles [1-5]. Optical binding of mesoscopic particles levitated in vacuum can pave the way towards the realisation of a large scale quantum bound array in cavity-optomechanics [6-9]. Recently we have demonstrated trapping and rotation of two mesoscopic particles in vacuum using a spatial-light-modulator-based approach to trap more than one particle, induce controlled rotation of individual particles, and mediate interparticle separation [10]. By trapping and rotating two vaterite particles, we observe intensity modulation of the scattered light at the sum and difference frequencies with respect to the individual rotation rates. This first demonstration of optical interference between two microparticles in vacuum has lead to a platform to explore optical binding. Here we demonstrate for the first time optically bound two microparticles mediated by light scattering in vacuum. We investigate autocorrelations between the two normal modes of oscillation, which are determined by the centre-of-mass and the relative positions of the two-particle system. In situ determination of the optical restoring force acting on the bound particles are based on measurement of the oscillation frequencies of the autocorrelation functions of the two normal modes, thereby providing a powerful and original platform to explore multiparticle entanglement in cavity-optomechanics.

Perturbative test of exact vacuum expectation values of local fields in affine Toda theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, Changrim; Baseilhac, P.; Kim, Chanju

Vacuum expectation values of local fields for all dual pairs of nonsimply laced affine Toda field theories recently proposed are checked against perturbative analysis. The computations based on Feynman diagram expansion are performed up to the two-loop level. We obtain, good agreement.

Optimal Design of a Hexakis Icosahedron Vacuum Based Lighter than Air Vehicle

DTIC Science & Technology

2017-03-23

box objectives and constraints. Results for a number of designs are presented and compared . iv Acknowledgements I would like to thank my advisors...Air Force Institute of Technology AFIT Scholar Theses and Dissertations 3-23-2017 Optimal Design of a Hexakis Icosahedron Vacuum Based Lighter than...administrator of AFIT Scholar. For more information, please contact richard.mansfield@afit.edu. Recommended Citation Schwemmer, Joseph R., "Optimal Design of a

A generator for unique quantum random numbers based on vacuum states

NASA Astrophysics Data System (ADS)

Gabriel, Christian; Wittmann, Christoffer; Sych, Denis; Dong, Ruifang; Mauerer, Wolfgang; Andersen, Ulrik L.; Marquardt, Christoph; Leuchs, Gerd

2010-10-01

Random numbers are a valuable component in diverse applications that range from simulations over gambling to cryptography. The quest for true randomness in these applications has engendered a large variety of different proposals for producing random numbers based on the foundational unpredictability of quantum mechanics. However, most approaches do not consider that a potential adversary could have knowledge about the generated numbers, so the numbers are not verifiably random and unique. Here we present a simple experimental setup based on homodyne measurements that uses the purity of a continuous-variable quantum vacuum state to generate unique random numbers. We use the intrinsic randomness in measuring the quadratures of a mode in the lowest energy vacuum state, which cannot be correlated to any other state. The simplicity of our source, combined with its verifiably unique randomness, are important attributes for achieving high-reliability, high-speed and low-cost quantum random number generators.

Photoemission-based microelectronic devices

PubMed Central

Forati, Ebrahim; Dill, Tyler J.; Tao, Andrea R.; Sievenpiper, Dan

2016-01-01

The vast majority of modern microelectronic devices rely on carriers within semiconductors due to their integrability. Therefore, the performance of these devices is limited due to natural semiconductor properties such as band gap and electron velocity. Replacing the semiconductor channel in conventional microelectronic devices with a gas or vacuum channel may scale their speed, wavelength and power beyond what is available today. However, liberating electrons into gas/vacuum in a practical microelectronic device is quite challenging. It often requires heating, applying high voltages, or using lasers with short wavelengths or high powers. Here, we show that the interaction between an engineered resonant surface and a low-power infrared laser can cause enough photoemission via electron tunnelling to implement feasible microelectronic devices such as transistors, switches and modulators. The proposed photoemission-based devices benefit from the advantages of gas-plasma/vacuum electronic devices while preserving the integrability of semiconductor-based devices. PMID:27811946

USC/AIAA student get away special project liquid droplet collector experiment

NASA Technical Reports Server (NTRS)

Levesque, Raymond J., II

1987-01-01

This experimental payload was developed in order to observe, in a micro-gravity vacuum environment, the characteristics and stability of a thin fluid film flowing across a slightly curved surface. The test apparatus was designed based upon various ground-based thin film investigations, combined with the constraints imposed by the rigors of launch and the space environment. Testing of the fluid test article at atmospheric pressure and in vacuum verified the design provisions employed concerning ultra-low inlet pressure pump construction, as well as confirming expected pressure losses in the system. During the course of hardware development and construction modifications were required; however, the overall payload configuration remained largely unchanged. This will allow for modification and reflight of the apparatus based upon the findings of the initial flight. The specific applications of this experiment include Liquid Droplet Radiator development and various forms of material transport in vacuum.

Ionization-Assisted Getter Pumping for Ultra-Stable Trapped Ion Frequency Standards

NASA Technical Reports Server (NTRS)

Tjoelker, Robert L.; Burt, Eric A.

2010-01-01

A method eliminates (or recovers from) residual methane buildup in getter-pumped atomic frequency standard systems by applying ionizing assistance. Ultra-high stability trapped ion frequency standards for applications requiring very high reliability, and/or low power and mass (both for ground-based and space-based platforms) benefit from using sealed vacuum systems. These systems require careful material selection and system processing (cleaning and high-temperature bake-out). Even under the most careful preparation, residual hydrogen outgassing from vacuum chamber walls typically limits the base pressure. Non-evaporable getter pumps (NEGs) provide a convenient pumping option for sealed systems because of low mass and volume, and no power once activated. An ion gauge in conjunction with a NEG can be used to provide a low mass, low-power method for avoiding the deleterious effects of methane buildup in high-performance frequency standard vacuum systems.

Application of programmable logic controllers to space simulation

NASA Technical Reports Server (NTRS)

Sushon, Janet

1992-01-01

Incorporating a state-of-the-art process control and instrumentation system into a complex system for thermal vacuum testing is discussed. The challenge was to connect several independent control systems provided by various vendors to a supervisory computer. This combination will sequentially control and monitor the process, collect the data, and transmit it to color a graphic system for subsequent manipulation. The vacuum system upgrade included: replacement of seventeen diffusion pumps with eight cryogenic pumps and one turbomolecular pump, replacing a relay based control system, replacing vacuum instrumentation, and upgrading the data acquisition system.

Improved integrated real-time contamination monitor. [with photomutliplier tube

NASA Technical Reports Server (NTRS)

1974-01-01

The laboratory model of the ITREM including the photomultiplier is described along with the utilization of the instrument. The preliminary designs are reviewed, and the development of the optical module for the instrument is discussed.

Development of New High Resolution Neutron Detector

NASA Astrophysics Data System (ADS)

Mostella, L. D., III; Rajabali, M.; Loureiro, D. P.; Grzywacz, R.

2017-09-01

Beta-delayed neutron emission is a prevalent form of decay for neutron-rich nuclei. This occurs when an unstable nucleus undergoes beta decay, but produces a daughter nucleus in an excited state above the neutron separation energy. The daughter nucleus then de-excites by ejecting one or more neutrons. We wish to map the states from which these nuclei decay via neutron spectroscopy using NEXT, a new high resolution neutron detector. NEXT utilizes silicon photomultipliers and 6 mm thick pulse-shape discriminating plastic scintillators, allowing for smaller and more compact modular geometries in the NEXT array. Timing measurements for the detector were performed and a resolution of 893 ps (FWHM) has been achieved so far. Aspects of the detector that were investigated and will be presented here include scintillator geometry, wrapping materials, fitting functions for the digitized signals, and electronic components coupled to the silicon photomultipliers for signal shaping.

Back-side readout semiconductor photomultiplier

DOEpatents

Choong, Woon-Seng; Holland, Stephen E

2014-05-20

This disclosure provides systems, methods, and apparatus related to semiconductor photomultipliers. In one aspect, a device includes a p-type semiconductor substrate, the p-type semiconductor substrate having a first side and a second side, the first side of the p-type semiconductor substrate defining a recess, and the second side of the p-type semiconductor substrate being doped with n-type ions. A conductive material is disposed in the recess. A p-type epitaxial layer is disposed on the second side of the p-type semiconductor substrate. The p-type epitaxial layer includes a first region proximate the p-type semiconductor substrate, the first region being implanted with p-type ions at a higher doping level than the p-type epitaxial layer, and a second region disposed on the first region, the second region being doped with p-type ions at a higher doping level than the first region.

Modeling of microjoule and millijoule energy LIDARs with PMT/SiPM/APD detectors: a sensitivity analysis.

PubMed

Agishev, Ravil

2018-05-10

This paper demonstrates a renewed concept and applications of the generalized methodology for atmospheric light detection and ranging (LIDAR) capability prediction as a continuation of a series of our previous works, where the dimensionless parameterization appeared as a tool for comparing systems of a different scale, design, and applications. The modernized concept applied to microscale and milliscale LIDARs with relatively new silicon photomultiplier detectors and traditional photomultiplier tube and avalanche photodiode detectors allowed prediction of the remote sensing instruments' performance and limitations. Such a generalized, uniform, and objective concept is applied for evaluation of the increasingly popular class of limited-energy LIDARs using the best optical detectors, operating on different targets (back-scatter or topographic, static or dynamic) and under intense sky background conditions. It can be used in the LIDAR community to compare different instruments and select the most suitable and effective ones for specific applications.

Photon Counting - One More Time

NASA Astrophysics Data System (ADS)

Stanton, Richard H.

2012-05-01

Photon counting has been around for more than 60 years, and has been available to amateurs for most of that time. In most cases single photons are detected using photomultiplier tubes, "old technology" that became available after the Second World War. But over the last couple of decades the perfection of CCD devices has given amateurs the ability to perform accurate photometry with modest telescopes. Is there any reason to still count photons? This paper discusses some of the strengths of current photon counting technology, particularly relating to the search for fast optical transients. Technology advances in counters and photomultiplier modules are briefly mentioned. Illustrative data are presented including FFT analysis of bright star photometry and a technique for finding optical pulses in a large file of noisy data. This latter technique is shown to enable the discovery of a possible optical flare on the polar variable AM Her.

The Full-Scale Prototype for the Fluorescence Detector Array of Single-Pixel Telescopes

NASA Astrophysics Data System (ADS)

Fujii, T.; Malacari, M.; Bellido, J. A.; Farmer, J.; Galimova, A.; Horvath, P.; Hrabovsky, M.; Mandat, D.; Matalon, A.; Matthews, J. N.; Merolle, M.; Ni, X.; Nozka, L.; Palatka, M.; Pech, M.; Privitera, P.; Schovanek, P.; Thomas, S. B.; Travnicek, P.

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for the next generation of ultrahigh-energy cosmic ray (UHECR) observatories, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of the highest energy cosmic rays. In the FAST design, a large field of view is covered by a few pixels at the focal plane of a mirror or Fresnel lens. Motivated by the successful detection of UHECRs using a prototype comprised of a single 200 mm photomultiplier-tube and a 1 m2 Fresnel lens system, we have developed a new "full-scale" prototype consisting of four 200 mm photomultiplier-tubes at the focus of a segmented mirror of 1.6 m in diameter. We report on the status of the full-scale prototype, including test measurements made during first light operation at the Telescope Array site in central Utah, U.S.A.

Method for passively compensating for temperature coefficient of gain in silicon photomultipliers and similar devices

DOEpatents

McKisson, John E.; Barbosa, Fernando

2015-09-01

A method for designing a completely passive bias compensation circuit to stabilize the gain of multiple pixel avalanche photo detector devices. The method includes determining circuitry design and component values to achieve a desired precision of gain stability. The method can be used with any temperature sensitive device with a nominally linear coefficient of voltage dependent parameter that must be stabilized. The circuitry design includes a negative temperature coefficient resistor in thermal contact with the photomultiplier device to provide a varying resistance and a second fixed resistor to form a voltage divider that can be chosen to set the desired slope and intercept for the characteristic with a specific voltage source value. The addition of a third resistor to the divider network provides a solution set for a set of SiPM devices that requires only a single stabilized voltage source value.

The detection of high charge cosmic ray nuclei. [by balloon-borne electronic particle telescope

NASA Technical Reports Server (NTRS)

Scarlett, W. R.; Freier, P. S.; Waddington, C. J.

1975-01-01

A large-area, light-weight electronic particle telescope was flown on a high altitude balloon in the summer of 1974 to study the heavy nuclei in the cosmic radiation. This telescope consisted of a double Cerenkov-double scintillator array composed of four 1.22 m diameter disk radiators mounted in light diffusion boxes, each looked at by multiple photomultipliers. The impact point of each particle on the scintillation radiators was determined by studying the relative signals observed by three equally spaced peripheral photomultipliers and one mounted at the center of the diffusion boxes. This telescope was flown in a configuration having a geometric factor of 0.45 sq m sr and observed some 5 x 10 to the 4 nuclei with Z exceeding 14 in a 11 hr exposure. The response and sensitivity of this telescope are discussed in detail.

Effects of 1- and 2-MeV electrons on photomultiplier tubes

NASA Technical Reports Server (NTRS)

Beatty, M. E., III; Debnam, W. J., Jr.; Meredith, B. D.

1976-01-01

Various types of photomultiplier tubes useful for space applications were irradiated with 1- and 2-MeV electrons at Van Allen radiation belt fluxes of 100,000 to 10 millions electrons/sq cm-sec. The increase in the dark current due to electron irradiation was observed at various bias voltages under worst-case conditions (no shielding). Results were presented in the form of dark current plotted against electron flux. All the tubes tested showed extremely large increases in dark current. Tube types 541A, 6217, 6199, and 6903 exhibited the largest increases under irradiation, whereas type 1P22 was affected the least. All the damage observed was transient. The luminescence produced in the optical window probably accounts for a large part of the dark-current increases, but there were some effects possibly due to direct irradiation of the photocathode and dynode chain.

A 780 × 800 μm2 Multichannel Digital Silicon Photomultiplier With Column-Parallel Time-to-Digital Converter and Basic Characterization

NASA Astrophysics Data System (ADS)

Mandai, Shingo; Jain, Vishwas; Charbon, Edoardo

2014-02-01

This paper presents a digital silicon photomultiplier (SiPM) partitioned in columns, whereas each column is connected to a column-parallel time-to-digital converter (TDC), in order to improve the timing resolution of single-photon detection. By reducing the number of pixels per TDC using a sharing scheme with three TDCs per column, the pixel-to-pixel skew is reduced. We report the basic characterization of the SiPM, comprising 416 single-photon avalanche diodes (SPADs); the characterization includes photon detection probability, dark count rate, afterpulsing, and crosstalk. We achieved 264-ps full-width at half maximum timing resolution of single-photon detection using a 48-fold column-parallel TDC with a temporal resolution of 51.8 ps (least significant bit), fully integrated in standard complementary metal-oxide semiconductor technology.

MuTRiG: a mixed signal Silicon Photomultiplier readout ASIC with high timing resolution and gigabit data link

NASA Astrophysics Data System (ADS)

Chen, H.; Briggl, K.; Eckert, P.; Harion, T.; Munwes, Y.; Shen, W.; Stankova, V.; Schultz-Coulon, H. C.

2017-01-01

MuTRiG is a mixed signal Silicon Photomultiplier readout ASIC designed in UMC 180 nm CMOS technology for precise timing and high event rate applications in high energy physics experiments and medical imaging. It is dedicated to the readout of the scintillating fiber detector and the scintillating tile detector of the Mu3e experiment. The MuTRiG chip extends the excellent timing performance of the STiCv3 chip with a fast digital readout for high rate applications. The high timing performance of the fully differential SiPM readout channels and 50 ps time binning TDCs are complemented by an upgraded digital readout logic and a 1.28 Gbps LVDS serial data link. The design of the chip and the characterization results of the analog front-end, TDC and the LVDS data link are presented.

Gain monitoring of telescope array photomultiplier cameras for the first 4 years of operation

NASA Astrophysics Data System (ADS)

Shin, B. K.; Tokuno, H.; Tsunesada, Y.; Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lim, S. I.; Machida, S.; Martens, K.; Martineau, J.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tomida, T.; Troitsky, S.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Wood, M.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

2014-12-01

The stability of the gain of the photomultiplier (PMT) camera for the Fluorescence Detector (FD) of the Telescope Array experiment was monitored using an 241Am loaded scintillator pulsers (YAP) and a diffused xenon flasher (TXF) for a selected set of 35 PMT-readout channels. From the monitoring of YAP pulses over four years of FD operation, we found slow monotonic drifts of PMT gains at a rate of -1.7 +1.7%/year. An average of the PMT gains over the 35 channels stayed nearly constant with a rate of change measured at -0.01±0.31(stat)±0.21(sys)%/year. No systematic decrease of the PMT gain caused by the night sky background was observed. Monitoring by the TXF also tracked the PMT gain drift of the YAP at 0.88±0.14(stat)%/year.

Radioactive source calibration test of the CMS Hadron Endcap Calorimeter test wedge with Phase I upgrade electronics

NASA Astrophysics Data System (ADS)

Chatrchyan, S.; Sirunyan, A. M.; Tumasyan, A.; Litomin, A.; Mossolov, V.; Shumeiko, N.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Spilbeeck, A.; Alves, G. A.; Aldá Júnior, W. L.; Hensel, C.; Carvalho, W.; Chinellato, J.; De Oliveira Martins, C.; Matos Figueiredo, D.; Mora Herrera, C.; Nogima, H.; Prado Da Silva, W. L.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Finger, M.; Finger, M., Jr.; Kveton, A.; Tomsa, J.; Adamov, G.; Tsamalaidze, Z.; Behrens, U.; Borras, K.; Campbell, A.; Costanza, F.; Gunnellini, P.; Lobanov, A.; Melzer-Pellmann, I.-A.; Muhl, C.; Roland, B.; Sahin, M.; Saxena, P.; Hegde, V.; Kothekar, K.; Pandey, S.; Sharma, S.; Beri, S. B.; Bhawandeep, B.; Chawla, R.; Kalsi, A.; Kaur, A.; Kaur, M.; Walia, G.; Bhattacharya, S.; Ghosh, S.; Nandan, S.; Purohit, A.; Sharan, M.; Banerjee, S.; Bhattacharya, S.; Chatterjee, S.; Das, P.; Guchait, M.; Jain, S.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Patil, M.; Sarkar, T.; Juodagalvis, A.; Afanasiev, S.; Bunin, P.; Ershov, Y.; Golutvin, I.; Malakhov, A.; Moisenz, P.; Smirnov, V.; Zarubin, A.; Chadeeva, M.; Chistov, R.; Danilov, M.; Popova, E.; Rusinov, V.; Andreev, Yu.; Dermenev, A.; Karneyeu, A.; Krasnikov, N.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Toms, M.; Zhokin, A.; Baskakov, A.; Belyaev, A.; Boos, E.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Kaminskiy, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Terkulov, A.; Bitioukov, S.; Elumakhov, D.; Kalinin, A.; Krychkine, V.; Mandrik, P.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin, S.; Volkov, A.; Sekmen, S.; Rumerio, P.; Adiguzel, A.; Bakirci, N.; Cerci, S.; Damarseckin, S.; Demiroglu, Z. S.; Dölek, F.; Dozen, C.; Dumanoglu, I.; Eskut, E.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kayis Topaksu, A.; Işik, C.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Tali, B.; Topakli, H.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Bilin, B.; Isildak, B.; Karapinar, G.; Murat Guler, A.; Ocalan, K.; Yalvac, M.; Zeyrek, M.; Atakisi, I. O.; Gülmez, E.; Kaya, M.; Kaya, O.; Koseyan, O. K.; Ozcelik, O.; Ozkorucuklu, S.; Tekten, S.; Yetkin, E. A.; Yetkin, T.; Cankocak, K.; Sen, S.; Boyarintsev, A.; Grynyov, B.; Levchuk, L.; Popov, V.; Sorokin, P.; Flacher, H.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Buccilli, A.; Cooper, S. I.; Henderson, C.; West, C.; Arcaro, D.; Gastler, D.; Hazen, E.; Rohlf, J.; Sulak, L.; Wu, S.; Zou, D.; Hakala, J.; Heintz, U.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Mao, Z.; Yu, D. R.; Gary, J. W.; Ghiasi Shirazi, S. M.; Lacroix, F.; Long, O. R.; Wei, H.; Bhandari, R.; Heller, R.; Stuart, D.; Yoo, J. H.; Chen, Y.; Duarte, J.; Lawhorn, J. M.; Nguyen, T.; Spiropulu, M.; Winn, D.; Abdullin, S.; Apresyan, A.; Apyan, A.; Banerjee, S.; Chlebana, F.; Freeman, J.; Green, D.; Hare, D.; Hirschauer, J.; Joshi, U.; Lincoln, D.; Los, S.; Pedro, K.; Spalding, W. J.; Strobbe, N.; Tkaczyk, S.; Whitbeck, A.; Linn, S.; Markowitz, P.; Martinez, G.; Bertoldi, M.; Hagopian, S.; Hagopian, V.; Kolberg, T.; Baarmand, M. M.; Noonan, D.; Roy, T.; Yumiceva, F.; Bilki, B.; Clarida, W.; Debbins, P.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Miller, M.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Schmidt, I.; Snyder, C.; Southwick, D.; Tiras, E.; Yi, K.; Al-bataineh, A.; Bowen, J.; Castle, J.; McBrayer, W.; Murray, M.; Wang, Q.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Baden, A.; Belloni, A.; Calderon, J. D.; Eno, S. C.; Feng, Y. B.; Ferraioli, C.; Grassi, T.; Hadley, N. J.; Jeng, G.-Y.; Kellogg, R. G.; Kunkle, J.; Mignerey, A.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Yang, Z. S.; Yao, Y.; Brandt, S.; D'Alfonso, M.; Hu, M.; Klute, M.; Niu, X.; Chatterjee, R. M.; Evans, A.; Frahm, E.; Kubota, Y.; Lesko, Z.; Mans, J.; Ruckstuhl, N.; Heering, A.; Karmgard, D. J.; Musienko, Y.; Ruchti, R.; Wayne, M.; Benaglia, A. D.; Medvedeva, T.; Mei, K.; Tully, C.; Bodek, A.; de Barbaro, P.; Galanti, M.; Garcia-Bellido, A.; Khukhunaishvili, A.; Lo, K. H.; Vishnevskiy, D.; Zielinski, M.; Agapitos, A.; Amouzegar, M.; Chou, J. P.; Hughes, E.; Saka, H.; Sheffield, D.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Mengke, T.; Muthumuni, S.; Undleeb, S.; Volobouev, I.; Wang, Z.; Goadhouse, S.; Hirosky, R.; Wang, Y.

2017-12-01

The Phase I upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics. The upgrade will eliminate the noise and the calibration drift of the Hybrid Photo-Diodes and enable the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade also includes increased longitudinal segmentation of the calorimeter readout, which allows pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational test, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source with upgrade electronics. The test successfully established the procedure for future source calibrations of the Hadron Endcap Calorimeters. Here we describe the instrumentation details and the operational experiences related to the sourcing test.

A technique for estimating the absolute gain of a photomultiplier tube

NASA Astrophysics Data System (ADS)

Takahashi, M.; Inome, Y.; Yoshii, S.; Bamba, A.; Gunji, S.; Hadasch, D.; Hayashida, M.; Katagiri, H.; Konno, Y.; Kubo, H.; Kushida, J.; Nakajima, D.; Nakamori, T.; Nagayoshi, T.; Nishijima, K.; Nozaki, S.; Mazin, D.; Mashuda, S.; Mirzoyan, R.; Ohoka, H.; Orito, R.; Saito, T.; Sakurai, S.; Takeda, J.; Teshima, M.; Terada, Y.; Tokanai, F.; Yamamoto, T.; Yoshida, T.

2018-06-01

Detection of low-intensity light relies on the conversion of photons to photoelectrons, which are then multiplied and detected as an electrical signal. To measure the actual intensity of the light, one must know the factor by which the photoelectrons have been multiplied. To obtain this amplification factor, we have developed a procedure for estimating precisely the signal caused by a single photoelectron. The method utilizes the fact that the photoelectrons conform to a Poisson distribution. The average signal produced by a single photoelectron can then be estimated from the number of noise events, without requiring analysis of the distribution of the signal produced by a single photoelectron. The signal produced by one or more photoelectrons can be estimated experimentally without any assumptions. This technique, and an example of the analysis of a signal from a photomultiplier tube, are described in this study.

A portable fluorescence detector for fast ultra trace detection of explosive vapors

NASA Astrophysics Data System (ADS)

Xin, Yunhong; He, Gang; Wang, Qi; Fang, Yu

2011-10-01

This paper developed a portable detector based on a specific material-based fluorescent sensing film for an ultra trace detection of explosives, such as 2,4,6-trinitrotoluene (TNT) or its derivate 2,4-dinitrotoluene (DNT), in ambient air or on objects tainted by explosives. The fluorescent sensing films are based on single-layer chemistry and the signal amplification effect of conjugated polymers, which exhibited higher sensitivity and shorter response time to TNT or DNT at their vapor pressures. Due to application of the light emitting diode and the solid state photomultiplier and the cross-correlation-based circuit design technology, the device has the advantages of low-power, low-cost, small size, and an improved signal to noise ratio. The results of the experiments showed that the detector can real-time detect and identify of explosive vapors at extremely low levels; it is suitable for the identification of suspect luggage, forensic analyses, or battlefields clearing.

A portable fluorescence detector for fast ultra trace detection of explosive vapors.

PubMed

Xin, Yunhong; He, Gang; Wang, Qi; Fang, Yu

2011-10-01

This paper developed a portable detector based on a specific material-based fluorescent sensing film for an ultra trace detection of explosives, such as 2,4,6-trinitrotoluene (TNT) or its derivate 2,4-dinitrotoluene (DNT), in ambient air or on objects tainted by explosives. The fluorescent sensing films are based on single-layer chemistry and the signal amplification effect of conjugated polymers, which exhibited higher sensitivity and shorter response time to TNT or DNT at their vapor pressures. Due to application of the light emitting diode and the solid state photomultiplier and the cross-correlation-based circuit design technology, the device has the advantages of low-power, low-cost, small size, and an improved signal to noise ratio. The results of the experiments showed that the detector can real-time detect and identify of explosive vapors at extremely low levels; it is suitable for the identification of suspect luggage, forensic analyses, or battlefields clearing.

NE-213-scintillator-based neutron detection system for diagnostic measurements of energy spectra for neutrons having energies greater than or equal to 0. 8 MeV created during plasma operations at the Princeton Tokamak Fusion Test Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickens, J.K.; Hill, N.W.; Hou, F.S.

1985-08-01

A system for making diagnostic measurements of the energy spectra of greater than or equal to 0.8-MeV neutrons produced during plasma operations of the Princeton Tokamak Fusion Test Reactor (TFTR) has been fabricated and tested and is presently in operation in the TFTR Test Cell Basement. The system consists of two separate detectors, each made up of cells containing liquid NE-213 scintillator attached permanently to RCA-8850 photomultiplier tubes. Pulses obtained from each photomultiplier system are amplified and electronically analyzed to identify and separate those pulses due to neutron-induced events in the detector from those due to photon-induced events in themore » detector. Signals from each detector are routed to two separate Analog-to-Digital Converters, and the resulting digitized information, representing: (1) the raw neutron-spectrum data; and (2) the raw photon-spectrum data, are transmited to the CICADA data-acquisition computer system of the TFTR. Software programs have been installed on the CICADA system to analyze the raw data to provide moderate-resolution recreations of the energy spectrum of the neutron and photon fluences incident on the detector during the operation of the TFTR. A complete description of, as well as the operation of, the hardware and software is given in this report.« less

QBeRT: an innovative instrument for qualification of particle beam in real-time

NASA Astrophysics Data System (ADS)

Gallo, G.; Lo Presti, D.; Bonanno, D. L.; Longhitano, F.; Bongiovanni, D. G.; Reito, S.; Randazzo, N.; Leonora, E.; Sipala, V.; Tommasino, F.

2016-11-01

This paper describes an innovative beam diagnostic and monitoring system composed of a position sensitive detector and a residual range detector, based on scintillating optical fiber and on an innovative read-out strategy and reconstruction algorithm. The position sensitive detector consists of four layers of pre-aligned and juxtaposed scintillating fibres arranged to form two identical overlying and orthogonal planes. The 500 μm square section fibres are optically coupled to two Silicon Photomultiplier arrays using a channel reduction system patented by the Istituto Nazionale di Fisica Nucleare. The residual range detector is a stack of sixty parallel layers of the same fibres used in the position detector, each of which is optically coupled to a channel of Silicon Photomultiplier array by wavelength shifting fibres. The sensitive area of the two detectors is 9 × 9 cm2. After being fully characterized at CATANA proton therapy facility, the performance of the prototypes was tested during last year also at TIFPA proton irradiation facility. The unique feature of these detectors is the possibility to work in imaging conditions (e.g. a particle at a time up to 106 particles per second) and in therapy conditions up to 109 particles per second. The combined use of the two detectors, in imaging conditions, as an example of application, allows the particle radiography of an object. In therapy conditions, in particular, the system measures the position, the profiles, the energy and the fluence of the beam.

Generation of multicolor vacuum ultraviolet pulses through four-wave sum-frequency mixing in argon

NASA Astrophysics Data System (ADS)

Shi, Liping; Li, Wenxue; Zhou, Hui; Wang, Di; Ding, Liang'en; Zeng, Heping

2013-11-01

We demonstrate efficient generation of multicolor vacuum ultraviolet pulses with excellent mode quality through χ(3)-based four-wave sum-frequency mixing and third-order harmonic generation of 400- and 267-nm femtosecond laser pulses in argon gas. The χ(3)-based nonlinear optical processes were optimized with appropriate control of gas pressure and group velocity delay between the driving pulses. Furthermore, the pulse breakup effects were observed for tightly focused ultraviolet pulses.

Photometer for detection of sodium day airglow.

NASA Technical Reports Server (NTRS)

Mcmahon, D. J.; Manring, E. R.; Patty, R. R.

1973-01-01

Description of a photometer for daytime ground-based measurements of sodium airglow emission. The photometer described can be characterized by the following principal features: (1) a narrow (4.5-A) interference filter for initial discrimination; (2) cooled photomultiplier detector to reduce noise from dark current fluctuations and chopping to eliminate the average dark current; (3) a sodium vapor resonance cell to provide an effective bandpass comparable to the Doppler line width; (4) separate detection of all light transmitted by the interference filter to evaluate the Rayleigh and Mie components within the Doppler width of the resonance cell; and (5) temperature quenching of the resonance cell to evaluate and account for instrumental imperfections.

Cosmic muon flux measurements at the Kimballton Underground Research Facility

NASA Astrophysics Data System (ADS)

Kalousis, L. N.; Guarnaccia, E.; Link, J. M.; Mariani, C.; Pelkey, R.

2014-08-01

In this article, the results from a series of muon flux measurements conducted at the Kimballton Underground Research Facility (KURF), Virginia, United States, are presented. The detector employed for these investigations, is made of plastic scintillator bars readout by wavelength shifting fibers and multianode photomultiplier tubes. Data was taken at several locations inside KURF, spanning rock overburden values from ~ 200 to 1450 m.w.e. From the extracted muon rates an empirical formula was devised, that estimates the muon flux inside the mine as a function of the overburden. The results are in good agreement with muon flux calculations based on analytical models and MUSIC.

Evaluation of a fast single-photon avalanche photodiode for measurement of early transmitted photons through diffusive media.

PubMed

Mu, Ying; Valim, Niksa; Niedre, Mark

2013-06-15

We tested the performance of a fast single-photon avalanche photodiode (SPAD) in measurement of early transmitted photons through diffusive media. In combination with a femtosecond titanium:sapphire laser, the overall instrument temporal response time was 59 ps. Using two experimental models, we showed that the SPAD allowed measurement of photon-density sensitivity functions that were approximately 65% narrower than the ungated continuous wave case at very early times. This exceeds the performance that we have previously achieved with photomultiplier-tube-based systems and approaches the theoretical maximum predicted by time-resolved Monte Carlo simulations.

Note: Neutron bang time diagnostic system on Shenguang-III prototype

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Qi; Chen, Jiabin; Liu, Zhongjie

A neutron bang time (NBT) diagnostic system has been implemented on Shenguang-III prototype. The bang time diagnostic system is based on a sensitive fusion neutron detector, which consists of a plastic scintillator and a micro-channel plate photomultiplier tube (PMT). An optical fiber bundle is used to couple the scintillator and the PMT. The bang time system is able to measure bang time above a neutron yield of 10{sup 7}. Bang times and start time of laser were related by probing x-ray pulses produced by 200 ps laser irradiating golden targets. Timing accuracy of the NBT is better than 60 ps.

Nuclear imaging of iodine uptake in mouse tissues

NASA Astrophysics Data System (ADS)

Hammond, W. T.; Bradley, E. L.; Qian, J.; Majewski, S.

2005-04-01

We have designed and employed a compact gamma camera based on pixellated scintillators and position-sensitive photomultipliers to obtain in vivo images in mice of biological substances tagged with 125-I. Biomedical imaging studies make use of radioactive isotopes of iodine. In these applications, protection of the thyroid from the effects of the radioactive material can be important. We have studied in vivo the effectiveness in mice of pre-administration of KI in various concentrations to evaluate both the biologically effective doses for thyroid protection and the potential for use in general sodium iodide symporter studies. These findings have important implications for both intentional and accidental exposure to radioiodine.

Light concentrator of the wide field of view Cherenkov telescope

NASA Astrophysics Data System (ADS)

Yang, Rui; Sheng, Xi Yi; Liao, Bo Lin

2016-10-01

The Wide Field of View Cherenkov Telescope (WFCT) is mainly constituted by optical reflector and focal-plane photomultiplier (PMT) array camera. In order to avoid loss of Cherenkov signal resulting from the dead area between circular PMT tubes and invalid fringe of each PMT, the light concentrator used as front window of PMT is considered to improve detective efficiency. Basing on the edge-ray principle and features of WFCT, several light concentrators are designed and simulated with ZEMAX. The result shows that the hollow hexahedral compound parabolic concentrator (hex-CPC) has good performance in collecting light. Moreover, the samples of the hollow hexahedral CPC have been manufactured and tested.

Radioiodine detector based on laser induced fluorescence

DOEpatents

McDonald, Jimmie R.; Baronavski, Andrew P.

1980-01-01

The invention involves the measurement of the concentration of the radioisotope .sup.129 I.sub.2 in the presence of a gas. The invention uses a laser to excite a sample of the .sup.129 I.sub.2 in a sample gas chamber and a reference sample of a known concentration of .sup.129 I.sub.2 in a reference gas chamber. The .sup.129 I.sub.2 in the sample and reference gas chamber each gives off fluorescence emissions which are received by photomultipliers which provide signals to a detector. The detector uses a ratioing technique to determine the concentration of .sup.129 I.sub.2 in the sample gas chamber.

Secondary Electron Emission Materials for Transmission Dynodes in Novel Photomultipliers: A Review

PubMed Central

Tao, Shu Xia; Chan, Hong Wah; van der Graaf, Harry

2016-01-01

Secondary electron emission materials are reviewed with the aim of providing guidelines for the future development of novel transmission dynodes. Materials with reflection secondary electron yield higher than three and transmission secondary electron yield higher than one are tabulated for easy reference. Generations of transmission dynodes are listed in the order of the invention time with a special focus on the most recent atomic-layer-deposition synthesized transmission dynodes. Based on the knowledge gained from the survey of secondary election emission materials with high secondary electron yield, an outlook of possible improvements upon the state-of-the-art transmission dynodes is provided. PMID:28774137

Characterization studies of silicon photomultipliers and crystals matrices for a novel time of flight PET detector

NASA Astrophysics Data System (ADS)

Auffray, E.; Ben Mimoun Bel Hadj, F.; Cortinovis, D.; Doroud, K.; Garutti, E.; Lecoq, P.; Liu, Z.; Martinez, R.; Paganoni, M.; Pizzichemi, M.; Silenzi, A.; Xu, C.; Zvolský, M.

2015-06-01

This paper describes the characterization of crystal matrices and silicon photomultiplier arrays for a novel Positron Emission Tomography (PET) detector, namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in a novel multimodal device, capable to support the development of new biomarkers for prostate and pancreatic tumors. The detector consists in two parts: a PET head mounted on an ultrasound probe and an external PET plate. The challenging goal of 1 mm spatial resolution for the PET image requires a detector with small crystal size, and therefore high channel density: 4096 LYSO crystals individually readout by Silicon Photomultipliers (SiPM) make up the external plate. The quality and properties of these components must be assessed before the assembly. The dark count rate, gain, breakdown voltage and correlated noise of the SiPMs are measured, while the LYSO crystals are evaluated in terms of light yield and energy resolution. In order to effectively reduce the noise in the PET image, high time resolution for the gamma detection is mandatory. The Coincidence Time Resolution (CTR) of all the SiPMs assembled with crystals is measured, and results show a value close to the demanding goal of 200 ps FWHM. The light output is evaluated for every channel for a preliminary detector calibration, showing an average of about 1800 pixels fired on the SiPM for a 511 keV interaction. Finally, the average energy resolution at 511 keV is about 13 %, enough for effective Compton rejection.

IceCube sensitivity for low-energy neutrinos from nearby supernovae

NASA Astrophysics Data System (ADS)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K. H.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Degner, T.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jakobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richard, A. S.; Richman, M.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Singh, K.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration

2011-11-01

This paper describes the response of the IceCube neutrino telescope located at the geographic south pole to outbursts of MeV neutrinos from the core collapse of nearby massive stars. IceCube was completed in December 2010 forming a lattice of 5160 photomultiplier tubes that monitor a volume of ~1 km3 in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can detect subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed, as well as the possibility to detect the neutronization burst, a short outbreak of \\barνe's released by electron capture on protons soon after collapse. Tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves, are investigated to illustrate IceCube's capability for supernova detection.

Reaching 200-ps timing resolution in a time-of-flight and depth-of-interaction positron emission tomography detector using phosphor-coated crystals and high-density silicon photomultipliers

PubMed Central

Kwon, Sun Il; Ferri, Alessandro; Gola, Alberto; Berg, Eric; Piemonte, Claudio; Cherry, Simon R.; Roncali, Emilie

2016-01-01

Abstract. Current research in the field of positron emission tomography (PET) focuses on improving the sensitivity of the scanner with thicker detectors, extended axial field-of-view, and time-of-flight (TOF) capability. These create the need for depth-of-interaction (DOI) encoding to correct parallax errors. We have proposed a method to encode DOI using phosphor-coated crystals. Our initial work using photomultiplier tubes (PMTs) demonstrated the possibilities of the proposed method, however, a major limitation of PMTs for this application is poor quantum efficiency in yellow light, corresponding to the wavelengths of the converted light by the phosphor coating. In contrast, the red-green-blue-high-density (RGB-HD) silicon photomultipliers (SiPMs) have a high photon detection efficiency across the visible spectrum. Excellent coincidence resolving time (CRT; <210  ps) was obtained by coupling RGB-HD SiPMs and  3 × 3 × 20  mm3 lutetium fine silicate crystals coated on a third of one of their lateral sides. Events were classified in three DOI bins (∼6.7-mm width) with an average sensitivity of 83.1%. A CRT of ∼200  ps combined with robust DOI encoding is a marked improvement in the phosphor-coated approach that we pioneered. For the first time, we read out these crystals with SiPMs and clearly demonstrated the potential of the RGB-HD SiPMs for this TOF-DOI PET detector. PMID:27921069

IceCube Sensitivity for Low-Energy Neutrinos from Nearby Supernovae

NASA Technical Reports Server (NTRS)

Stamatikos, M.; Abbasi, R.; Berghaus, P.; Chirkin, D.; Desiati, P.; Diaz-Velez, J.; Dumm, J. P.; Eisch, J.; Feintzeig, J.; Hanson, K.;

EVALUATION OF MASS FLUX TO AND FROM GROUND WATER USING A VERTICAL FLUX MODEL (VFLUX): APPLICATION TO THE SOIL VACUUM EXTRACTION CLOSURE PROBLEM

EPA Science Inventory

Site closure for soil vacuum extraction (SVE) application typically requires attainment of specified soil concentration standards based on the premise that mass flux from the vadose zone to ground water not result in levels exceeding maximum contaminant levels (MCLSs). Unfortuna...

Ultrahigh vacuum process for the deposition of nanotubes and nanowires

DOEpatents

Das, Biswajit; Lee, Myung B

2015-02-03

A system and method A method of growing an elongate nanoelement from a growth surface includes: a) cleaning a growth surface on a base element; b) providing an ultrahigh vacuum reaction environment over the cleaned growth surface; c) generating a reactive gas of an atomic material to be used in forming the nanoelement; d) projecting a stream of the reactive gas at the growth surface within the reactive environment while maintaining a vacuum of at most 1.times.10.sup.-4 Pascal; e) growing the elongate nanoelement from the growth surface within the environment while maintaining the pressure of step c); f) after a desired length of nanoelement is attained within the environment, stopping direction of reactive gas into the environment; and g) returning the environment to an ultrahigh vacuum condition.

All-optical signatures of strong-field QED in the vacuum emission picture

NASA Astrophysics Data System (ADS)

Gies, Holger; Karbstein, Felix; Kohlfürst, Christian

2018-02-01

We study all-optical signatures of the effective nonlinear couplings among electromagnetic fields in the quantum vacuum, using the collision of two focused high-intensity laser pulses as an example. The experimental signatures of quantum vacuum nonlinearities are encoded in signal photons, whose kinematic and polarization properties differ from the photons constituting the macroscopic laser fields. We implement an efficient numerical algorithm allowing for the theoretical investigation of such signatures in realistic field configurations accessible in experiment. This algorithm is based on a vacuum emission scheme and can readily be adapted to the collision of more laser beams or further involved field configurations. We solve the case of two colliding pulses in full 3 +1 -dimensional spacetime and identify experimental geometries and parameter regimes with improved signal-to-noise ratios.

The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

The use of the Molecular Adsorber Coating technology to mitigate vacuum chamber contamination during Pathfinder testing for the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-09-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Vacuum plasma coatings for turbine blades

NASA Technical Reports Server (NTRS)

Holmes, R. R.

1985-01-01

Turbine blades, vacuum plasma spray coated with NiCrAlY, CoCrAlY or NiCrAlY/Cr2O3, were evaluated and rated superior to standard space shuttle main engine (SSME) coated blades. Ratings were based primarily on 25 thermal cycles in the MSFC Burner Rig Tester, cycling between 1700 F (gaseous H2) and -423 F (liquid H2). These tests showed no spalling on blades with improved vacuum plasma coatings, while standard blades spalled. Thermal barrier coatings of ZrO2, while superior to standard coatings, lacked the overall performance desired. Fatigue and tensile specimens, machined from MAR-M-246(Hf) test bars identical to the blades were vacuum plasma spray coated, diffusion bond treated, and tested to qualify the vacuum plasma spray process for flight hardware testing and application. While NiCrAlY/Cr2O3 offers significant improvement over standard coatings in durability and thermal protection, studies continue with an objective to develop coatings offering even greater improvements.

Optimization of a vacuum chamber for vibration measurements.

PubMed

Danyluk, Mike; Dhingra, Anoop

2011-10-01

A 200 °C high vacuum chamber has been built to improve vibration measurement sensitivity. The optimized design addresses two significant issues: (i) vibration measurements under high vacuum conditions and (ii) use of design optimization tools to reduce operating costs. A test rig consisting of a cylindrical vessel with one access port has been constructed with a welded-bellows assembly used to seal the vessel and enable vibration measurements in high vacuum that are comparable with measurements in air. The welded-bellows assembly provides a force transmissibility of 0.1 or better at 15 Hz excitation under high vacuum conditions. Numerical results based on design optimization of a larger diameter chamber are presented. The general constraints on the new design include material yield stress, chamber first natural frequency, vibration isolation performance, and forced convection heat transfer capabilities over the exterior of the vessel access ports. Operating costs of the new chamber are reduced by 50% compared to a preexisting chamber of similar size and function.

Waveguide quantum electrodynamics in squeezed vacuum

NASA Astrophysics Data System (ADS)

You, Jieyu; Liao, Zeyang; Li, Sheng-Wen; Zubairy, M. Suhail

2018-02-01

We study the dynamics of a general multiemitter system coupled to the squeezed vacuum reservoir and derive a master equation for this system based on the Weisskopf-Wigner approximation. In this theory, we include the effect of positions of the squeezing sources which is usually neglected in the previous studies. We apply this theory to a quasi-one-dimensional waveguide case where the squeezing in one dimension is experimentally achievable. We show that while dipole-dipole interaction induced by ordinary vacuum depends on the emitter separation, the two-photon process due to the squeezed vacuum depends on the positions of the emitters with respect to the squeezing sources. The dephasing rate, decay rate, and the resonance fluorescence of the waveguide-QED in the squeezed vacuum are controllable by changing the positions of emitters. Furthermore, we demonstrate that the stationary maximum entangled NOON state for identical emitters can be reached with arbitrary initial state when the center-of-mass position of the emitters satisfies certain conditions.

Traveling-Wave Tubes

NASA Technical Reports Server (NTRS)

Kory, Carol L.

1998-01-01

The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

Effectiveness of oxygen barrier oven bags in low temperature cooking on reduction of warmed-over flavor in beef roasts.

PubMed

Lepper-Blilie, A N; Berg, E P; Buchanan, D S; Keller, W L; Maddock-Carlin, K R; Berg, P T

2014-03-01

A 3×3×2 factorial was utilized to determine if roast size (small, medium, large), cooking method (open-pan, oven bag, vacuum bag), and heating process (fresh, reheated) prevented warmed-over flavor (WOF) in beef clod roasts. Fresh vacuum bag and reheated open-pan roasts had higher cardboardy flavor scores compared with fresh open-pan roast scores. Reheated roasts in oven and vacuum bags did not differ from fresh roasts for cardboardy flavor. Brothy and fat intensity were increased in reheated roasts in oven and vacuum bags compared with fresh roasts in oven and vacuum bags. Differences in TBARS were found in the interaction of heating process and roast size with the fresh and reheated large, and reheated medium roasts having the lowest values. Based on TBARS data, to prevent WOF in reheated beef roasts, a larger size roast in a cooking bag is the most effective method. Copyright © 2013 Elsevier Ltd. All rights reserved.

Achieving ultrahigh vacuum in an unbaked chamber with glow discharge conditioning

NASA Astrophysics Data System (ADS)

Khan, Ziauddin; Semwal, Pratibha; Dhanani, Kalpesh R.; Raval, Dilip C.; Pradhan, Subrata

2017-01-01

Glow discharge conditioning (GDC) has long been accepted as one of the basic wall conditioning techniques for achieving ultrahigh vacuum in an unbaked chamber. As a part of this fundamental experimental study, a test chamber has been fabricated from stainless steel 304 L with its inner surface electropolished on which a detailed investigation has been carried out. Both helium and hydrogen gases have been employed as discharge cleaning medium. The discharge cleaning was carried out at 0.1 A / m 2 current density with working pressure maintained at 1.0 × 10 -2 mbar. It was experimentally observed that the pump-down time to attain the base pressure 10 -8 mbar was reduced by 62% compared to the unbaked chamber being pumped to this ultimate vacuum. The results were similar irrespective of whether the discharge cleaning medium is either hydrogen or helium. It was also experimentally established that a better ultimate vacuum could be achieved as compared to theoretically calculated ultimate vacuum with the help of discharge cleaning.

Engineering and performance (NEMA and animal) of a lower-cost higher-resolution animal PET/CT scanner using photomultiplier-quadrant-sharing detectors.

PubMed

Wong, Wai-Hoi; Li, Hongdi; Baghaei, Hossain; Zhang, Yuxuan; Ramirez, Rocio A; Liu, Shitao; Wang, Chao; An, Shaohui

2012-11-01

The dedicated murine PET (MuPET) scanner is a high-resolution, high-sensitivity, and low-cost preclinical PET camera designed and manufactured at our laboratory. In this article, we report its performance according to the NU 4-2008 standards of the National Electrical Manufacturers Association (NEMA). We also report the results of additional phantom and mouse studies. The MuPET scanner, which is integrated with a CT camera, is based on the photomultiplier-quadrant-sharing concept and comprises 180 blocks of 13 × 13 lutetium yttrium oxyorthosilicate crystals (1.24 × 1.4 × 9.5 mm(3)) and 210 low-cost 19-mm photomultipliers. The camera has 78 detector rings, with an 11.6-cm axial field of view and a ring diameter of 16.6 cm. We measured the energy resolution, scatter fraction, sensitivity, spatial resolution, and counting rate performance of the scanner. In addition, we scanned the NEMA image-quality phantom, Micro Deluxe and Ultra-Micro Hot Spot phantoms, and 2 healthy mice. The system average energy resolution was 14% at 511 keV. The average spatial resolution at the center of the field of view was about 1.2 mm, improving to 0.8 mm and remaining below 1.2 mm in the central 6-cm field of view when a resolution-recovery method was used. The absolute sensitivity of the camera was 6.38% for an energy window of 350-650 keV and a coincidence timing window of 3.4 ns. The system scatter fraction was 11.9% for the NEMA mouselike phantom and 28% for the ratlike phantom. The maximum noise-equivalent counting rate was 1,100 at 57 MBq for the mouselike phantom and 352 kcps at 65 MBq for the ratlike phantom. The 1-mm fillable rod was clearly observable using the NEMA image-quality phantom. The images of the Ultra-Micro Hot Spot phantom also showed the 1-mm hot rods. In the mouse studies, both the left and right ventricle walls were clearly observable, as were the Harderian glands. The MuPET camera has excellent resolution, sensitivity, counting rate, and imaging performance. The data show it is a powerful scanner for preclinical animal study and pharmaceutical development.

Detectors for optical communications: A review

NASA Technical Reports Server (NTRS)

Katz, J.

1983-01-01

Detectors for optical communications in the visible and near infrared regions of the spectrum are reviewed. The three generic types of detectors described are: photomultipliers, photodiodes and avalanche photodiodes. Most of the information is applicable to other optical communications systems.

K(3)EDTA Vacuum Tubes Validation for Routine Hematological Testing.

PubMed

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Poli, Giovanni; Solero, Giovanni Pietro; Picheth, Geraldo; Guidi, Gian Cesare

2012-01-01

Background and Objective. Some in vitro diagnostic devices (e.g, blood collection vacuum tubes and syringes for blood analyses) are not validated before the quality laboratory managers decide to start using or to change the brand. Frequently, the laboratory or hospital managers select the vacuum tubes for blood collection based on cost considerations or on relevance of a brand. The aim of this study was to validate two dry K(3)EDTA vacuum tubes of different brands for routine hematological testing. Methods. Blood specimens from 100 volunteers in two different K(3)EDTA vacuum tubes were collected by a single, expert phlebotomist. The routine hematological testing was done on Advia 2120i hematology system. The significance of the differences between samples was assessed by paired Student's t-test after checking for normality. The level of statistical significance was set at P < 0.05. Results and Conclusions. Different brand's tubes evaluated can represent a clinically relevant source of variations only on mean platelet volume (MPV) and platelet distribution width (PDW). Basically, our validation will permit the laboratory or hospital managers to select the brand's vacuum tubes validated according to him/her technical or economical reasons for routine hematological tests.

K3EDTA Vacuum Tubes Validation for Routine Hematological Testing

PubMed Central

Lima-Oliveira, Gabriel; Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Poli, Giovanni; Solero, Giovanni Pietro; Picheth, Geraldo; Guidi, Gian Cesare

2012-01-01

Background and Objective. Some in vitro diagnostic devices (e.g, blood collection vacuum tubes and syringes for blood analyses) are not validated before the quality laboratory managers decide to start using or to change the brand. Frequently, the laboratory or hospital managers select the vacuum tubes for blood collection based on cost considerations or on relevance of a brand. The aim of this study was to validate two dry K3EDTA vacuum tubes of different brands for routine hematological testing. Methods. Blood specimens from 100 volunteers in two different K3EDTA vacuum tubes were collected by a single, expert phlebotomist. The routine hematological testing was done on Advia 2120i hematology system. The significance of the differences between samples was assessed by paired Student's t-test after checking for normality. The level of statistical significance was set at P < 0.05. Results and Conclusions. Different brand's tubes evaluated can represent a clinically relevant source of variations only on mean platelet volume (MPV) and platelet distribution width (PDW). Basically, our validation will permit the laboratory or hospital managers to select the brand's vacuum tubes validated according to him/her technical or economical reasons for routine hematological tests. PMID:22888448

ISRU Soil Mechanics Vacuum Facility: Soil Bin Preparation and Simulant Strength Characterization

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Wilkinson, Allen

2012-01-01

Testing in relevant environments is key to exploration mission hardware development. This is true on both the component level (in early development) and system level (in late development stages). During ISRU missions the hardware will interface with the soil (digging, roving, etc) in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, conditioned simulant bed. However, in earth-based granular media, such as lunar soil simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. The Vacuum Facility #13, a mid-size chamber (3.66m tall, 1.5m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64m deep by 0.914m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types have been used. An electric cone penetrometer was used to measure simulant strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5Torr, regardless of the pump rate. However, slow off gassing of the soil lead to long test times, a full week, to reach 10-5Torr. This work highlights the need for robotic machine-simulant hardware and operations in vacuum to expeditiously perform (sub-)systems tests.

Preliminary investigations on a new method of retaining the colour of shucked cockles ( Anadara Granosa), and the extension of shelflife by gamma irradiation and vacuum packing

NASA Astrophysics Data System (ADS)

Ng, Cher Siang; Low, Lai Kim; Chia, Lawrence H. L.

Live cockles were incubated in atmospheres containing different concentrations of carbon monoxide. Since CO combines more readily with myoglobin and haemoglobin than oxygen, the formation of in vivo deoxygenated haemoglobins and post mortem formation of methaemoglobin were retarded by the more stable carboxyhaemoglobin (HbCO). The bright red colour of the stable HbCO is retained during storage, giving the desired colour to the cockles. The colour of normal, chilled cockle meat deteriorated after 3 days ice storage while those treated with 50 and 100% CO retained the bright deep orange colour up to 10 days storage. Irradiation caused faster colour deterioration in both CO and non-CO treated samples. Vacuum packing influenced the colour of the cockles with irradiation and with CO treatments. In non-CO treated, irradiated samples, the effect of vacuum packing was not obvious. In CO treated, irradiated samples, vacuum packing retarded the deterioration of colour. Odour developments were influenced by irradiation, vacuum packing and storage temperature, and were not influenced by CO treatments. Irradiation suppressed the development of odour for the first 11 days storage (0°C) while vacuum packing depressed the odour by lowering its intensity instead. Odour development was slowed down by lowering the storage temperature. The odour of shucked cockles was rejected within one day at room temperature (26-28°C) while at 0°C the odour of the shucked cockles was still acceptable after 10 days. Suitable chemical indices for quality are K value and TVBN. Treatment with CO did not influence the K value development. Vacuum packing produced the highest K values after 19 days storage (0°C), while irradiated samples had higher K values than non-irradiated samples. The TVBN increased with storage and is an indicator of the odour development. The use of CO treatment extended the shelflife of the cockles based on appearance. A combination of CO treatment, vacuum packing, ice storage and irradiation extended the shelflife to beyond 18 days, based on odour, colour, and overall appearance.

Wafer-level hermetic vacuum packaging by bonding with a copper-tin thin film sealing ring

NASA Astrophysics Data System (ADS)

Akashi, Teruhisa; Funabashi, Hirofumi; Takagi, Hideki; Omura, Yoshiteru; Hata, Yoshiyuki

2018-04-01

A wafer-level hermetic vacuum packaging technology intended for use with MEMS devices was developed based on a copper-tin (CuSn) thin film sealing ring. To allow hermetic packaging, the shear strength of the CuSn thin film bond was improved by optimizing the pretreatment conditions. As a result, an average shear strength of 72.3 MPa was obtained and a cavity that had been hermetically sealed using wafer-level packaging (WLP) maintained its vacuum for 1.84 years. The total pressures in the cavities and the partial pressures of residual gases were directly determined with an ultra-low outgassing residual gas analyzer (RGA) system. Hermeticity was evaluated based on helium leak rates, which were calculated from helium pressures determined with the RGA system. The resulting data showed that a vacuum cavity following 1.84 years storage had a total pressure of 83.1 Pa, contained argon as the main residual gas and exhibited a helium leak rate as low as 1.67  ×  10-17 Pa · m3 s-1, corresponding to an air leak rate of 6.19  ×  10-18 Pa · m3 s-1. The RGA data demonstrate that WLP using a CuSn thin film sealing ring permits ultra-high hermeticity in conjunction with long-term vacuum packaging that is applicable to MEMS devices.

Transverse Uniaxial Composite Thermal Properties Data Base of Thermally Conductive Graphite Fibers with and without Contiguous Grown Graphite Fins

DTIC Science & Technology

2013-07-01

Vacuum Heat Capacity: Test Method: Conventional MCDS Heating Rate 2 oC/min Temperature(oC): -75 -50 -25 0 25 50 75 100 Average (J/goC): 0.5555...PreConditioning Time-Duration: 24hrs at 125oC and -29inch Vacuum Heat Capacity: Test Method: Conventional MCDS Heating Rate 2 oC/min Temperature(oC...29inch Vacuum Heat Capacity: Test Method: Conventional MCDS Heating Rate 2 oC/min Temperature(oC): -75 -50 -25 0 - - - - Average (J/goC

Circularly polarized vacuum field in three-dimensional chiral photonic crystals probed by quantum dot emission

NASA Astrophysics Data System (ADS)

Takahashi, S.; Ota, Y.; Tajiri, T.; Tatebayashi, J.; Iwamoto, S.; Arakawa, Y.

2017-11-01

The modification of a circularly polarized vacuum field in three-dimensional chiral photonic crystals was measured by spontaneous emission from quantum dots in the structures. Due to the circularly polarized eigenmodes along the helical axis in the GaAs-based mirror-asymmetric structures we studied, we observed highly circularly polarized emission from the quantum dots. Both spectroscopic and time-resolved measurements confirmed that the obtained circularly polarized light was influenced by a large difference in the photonic density of states between the orthogonal components of the circular polarization in the vacuum field.

Vacuum system design and tritium inventory for the charge exchange diagnostic on the Tokamak Fusion Test Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medley, S.S.

The application of charge exchange analyzers for the measurement of ion temperature in fusion plasma experiments requires a direct connection between the diagnostic and plasma-discharge vacuum chambers. Differential pumping of the gas load from the diagnostic stripping cell operated at > or approx. = 10/sup -3/ Torr is required to maintain the analyzer chamber at a pressure of < or approx. = 10/sup -6/ Torr. The migration of gases between the diagnostic and plasma vacuum chambers must be minimized. In particular, introduction of the analyzer stripping cell gas into the plasma chamber having a base pressure of < or approx.more » = 10/sup -8/ Torr must be suppressed. The charge exchange diagnostic for the Tokamak Fusion Test Reactor (TFTR) is comprised of two analyzer systems designed to contain a total of 18 independent mass/energy analyzers and one diagnostic neutral beam rated at 80 keV, 15 A. The associated arrays of multiple, interconnected vacuum systems were analyzed using the Vacuum System Transient Simulator (Vsts) computer program which models the transient transport of multigas species through complex networks of ducts, valves, traps, vacuum pumps, and other related vacuum system components. In addition to providing improved design performance at reduced costs, the analysis yields estimates for the exchange of tritium from the torus to the diagnostic components and of the diagnostic working gases to the torus.« less

Overview of High Power Vacuum Dry RF Load Designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasnykh, Anatoly

2015-08-27

A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is tomore » use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.« less

A portable gas sensor based on cataluminescence.

PubMed

Kang, C; Tang, F; Liu, Y; Wu, Y; Wang, X

2013-01-01

We describe a portable gas sensor based on cataluminescence. Miniaturization of the gas sensor was achieved by using a miniature photomultiplier tube, a miniature gas pump and a simple light seal. The signal to noise ratio (SNR) was considered as the evaluation criteria for the design and testing of the sensor. The main source of noise was from thermal background. Optimal working temperature and flow rate were determined experimentally from the viewpoint of improvement in SNR. A series of parameters related to analytical performance was estimated. The limitation of detection of the sensor was 7 ppm (SNR = 3) for ethanol and 10 ppm (SNR = 3) for hydrogen sulphide. Zirconia and barium carbonate were respectively selected as nano-sized catalysts for ethanol and hydrogen sulphide. Copyright © 2012 John Wiley & Sons, Ltd.

SiPM-based azimuthal position sensor in ANITA-IV Hi-Cal Antarctic balloon experiment

NASA Astrophysics Data System (ADS)

Novikov, A.; Besson, D.; Chernysheva, I.; Dmitrenko, V.; Grachev, V.; Petrenko, D.; Prohira, S.; Shustov, A.; Ulin, S.; Uteshev, Z.; Vlasik, K.

2017-01-01

Hi-Cal (High-Altitude Calibration) is a balloon-borne experiment that will be launched in December, 2016 in Antarctica following ANITA-IV (Antarctic Impulsive Transient Antenna) and will generate a broad-band pulse over the frequency range expected from radiation induced by a cosmic ray shower. Here, we describe a device based on an array of silicon photomultipliers (SiPMs) for determination of the azimuthal position of Hi-Cal. The angular resolution of the device is about 3 degrees. Since at the float altitude of ˜38 km the pressure will be ˜0.5 mbar and temperature ˜ - 20 °C, the equipment has been tested in a chamber over a range of corresponding pressures (0.5 ÷ 1000) mbar and temperatures (-40 ÷ +50) °C.

Study of n- γ discrimination by zero-crossing method with SiPM based scintillation detectors

NASA Astrophysics Data System (ADS)

Grodzicka-Kobylka, M.; Szczesniak, T.; Moszyński, M.; Swiderski, L.; Wolski, D.; Baszak, J.; Korolczuk, S.; Schotanus, P.

2018-03-01

The paper presents a study of n / γ discrimination with 4x4 ch and 8x8 ch Multi Pixel Photon Counter (MPPC) arrays in neutron detectors based on Stilbene and EJ299-33 plastic scintillators. The n / γ discrimination showed an excellent capability of the MPPC arrays, comparable to that observed earlier with the classical PMTs. Particularly, an application of a zero-crossing method of n - γ discrimination prevented deterioration of the discrimination by the slow response of the Silicon Photomultiplier (SiPM, or MPPC interchangeably) array related to its large capacitance. It was confirmed by a good agreement of the Figure of Merit normalized to the number of photoelectrons determined for the MPPC arrays and XP5500 PMT.

An experimental sample of the field gamma-spectrometer based on solid state Si-photomultiplier

NASA Astrophysics Data System (ADS)

Denisov, Viktor; Korotaev, Valery; Titov, Aleksandr; Blokhina, Anastasia; Kleshchenok, Maksim

2017-05-01

Design of optical-electronic devices and systems involves the selection of such technical patterns that under given initial requirements and conditions are optimal according to certain criteria. The original characteristic of the OES for any purpose, defining its most important feature ability is a threshold detection. Based on this property, will be achieved the required functional quality of the device or system. Therefore, the original criteria and optimization methods have to subordinate to the idea of a better detectability. Generally reduces to the problem of optimal selection of the expected (predetermined) signals in the predetermined observation conditions. Thus the main purpose of optimization of the system when calculating its detectability is the choice of circuits and components that provide the most effective selection of a target.

A fiber optic, ultraviolet light-emitting diode-based, two wavelength fluorometer for monitoring reactive adsorption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granz, Christopher D.; Whitten, James E., E-mail: James-Whitten@uml.edu; Schindler, Bryan J.

Construction and use of an ultraviolet light-emitting diode-based fluorometer for measuring photoluminescence (PL) from powder samples with a fiber optic probe is described. Fluorescence at two wavelengths is detected by miniature photomultiplier tubes, each equipped with a different band pass filter, whose outputs are analyzed by a microprocessor. Photoluminescent metal oxides and hydroxides, and other semiconducting nanoparticles, often undergo changes in their emission spectra upon exposure to reactive gases, and the ratio of the PL intensities at two wavelengths is diagnostic of adsorption. Use of this instrument for reactive gas sensing and gas filtration applications is illustrated by measuring changesmore » in the PL ratio for zirconium hydroxide and zinc oxide particles upon exposure to air containing low concentrations of sulfur dioxide.« less