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5. The efficiency of thermal neutron detection and collimation with microchannel plates of square and circular geometry

Author

Tremsin, A S, Feller, W B, Downing, R G, and Mildner, DFR

Subjects
high spatial resolution, neutron detection, neutron optics, position sensitive detectors
Abstract

Detectors with microchannel plates (MCPs) are currently widely used in photon and charged particle detection with high spatial (similar to 10 um) and temporal (< 0.5 ns) resolution. All the advances in MCP detection technologies can be successfully implemented for the detection of thermal neutrons by using MCPs manufactured from a modified glass mixture doped with neutron absorbing atoms. In this paper, we compare the efficiency of thermal neutron detection for two standard MCP geometries: circular-pore and square-pore MCPs doped with the B-10 isotope. The results of our modeling indicate that the detection of thermal neutrons with a square-pore MCP is 11%-23% more efficient than for the circular geometry, and can be higher than 70% for the existing MCP technology.The same MCPs can be used as very efficient and compact thermal neutron collimators. In this paper, we compare the efficiency of circular- and square-pore MCP collimators with the help of our model, the validity of which has already been verified by our experimental measurements reported last year. The rocking curve of 5-mm and 2.5-mm thick MCPs doped with 3 mole % of (nat)Gd2O3 is predicted to be only +/- 0.1 degrees and +/- 0.3 degrees wide, respectively, for both geometries. A very compact device with high thermal neutron detection efficiency and angular sensitivity can be built by combining an MCP neutron detector with an MCP collimator.

Published
2005

6. Efficiency optimization of microchannel plate (MCP) neutron imaging detectors. 1. Square channels with B-10 doping

Author

Tremsin, A S, Feller, W B, and Downing, R G

Subjects
neutron detection, detection efficiency, neutron imaging
Abstract

Microchannel plate (MCP) event-counting imaging detectors with very high spatial resolution (~10 um) and timing accuracy (~100 ps) are widely employed for the detection and imaging applications of electrons and ions, as well as UV and X-ray photons. Recently, it was demonstrated that the many advantages of MCPs are also applicable to neutron detection with high two-dimensional spatial resolution. Boron, enriched in the isotope B-10, was added to the MCP glass structure to enhance the neutron interaction within the MCP through the B-10(n, alpha)(7) Li reaction. The energetic charged particle reaction products release secondary electrons directly into MCP channels, initiating an electron avalanche and a subsequent strong output pulse. In this paper we present a detailed model for calculating the quantum detection efficiency of MCP neutron detectors incorporating 10B, for the specific case of square channel MCP geometry. This model predicts that for thermal neutrons (0.025 eV), MCP detection efficiencies of up to 78% are possible using square channels. We also show theoretically that square channel MCPs should have a very sharp (similar to17 mrad) angular drop in sensitivity for detection of normal incidence neutrons, opening up new possibilities for angle-sensitive neutron imaging as well as collimation. The calculations can be used to optimize MCP neutron detection efficiency for a variety of applications. In a subsequent companion paper, the model will be extended to the case of hexagonally packed circular channels. (C) 2004 Elsevier B.V. All rights reserved.

Published
2005

7. EMERGING VIRUSES ARE AN UNDERESTIMATED CAUSE OF UNDIAGNOSED FEBRILE ILLNESS IN UGANDA

Author

Ashraf, S., primary, Jerome, H., additional, Davis, C., additional, Shepherd, J., additional, Vattipally, S., additional, Filipe, A., additional, Namuwulya, P., additional, Mayanja, M., additional, Downing, R., additional, Salazar, J., additional, Bukenya, H., additional, Salazar, M., additional, Witkowska, W., additional, Atim, S., additional, Balinandi, S., additional, Lutwama, J., additional, Kaleebu, P., additional, Bwogi, J., additional, and Thomson, E., additional

Published
2023
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8. A precise measurement of 180 GeV muon energy losses in iron

Author

Amaral, P, Amorim, A, Anderson, K, Artikov, A, Benetta, R, Berglund, S, Biscarat, C, Blanch, O, Blanchot, G, Bogush, A, Bohm, C, Boldea, V, Borisov, O, Bosman, M, Bromberg, C, Bravo, S, Budagov, J, Burdin, S, Caloba, L, Camarena, F, Carvalho, J, Castillo, MV, Cavalli-Sforza, M, Cavasinni, V, Cerqueira, AS, Chadelas, R, Chirikov-Zorin, I, Chlachidze, G, Cobal, M, Cogswell, F, Cologna, S, Constantinescu, S, Costanzo, D, Cowan, B, Crouau, M, Daudon, F, David, M, Davidek, T, Dawson, J, De, K, Delfino, M, Del Prete, T, De Santo, A, Di Girolamo, B, Dita, S, Downing, R, Engström, M, Errede, D, Errede, S, Fassi, F, Fenyuk, A, Ferrer, A, Flaminio, V, Flix, J, Garabik, R, Gil, I, Gildemeister, O, Glagolev, V, Gomes, A, Gonzalez, V, González De La Hoz, S, Grabski, V, Grenier, P, Hakopian, H, Haney, M, Hellman, S, Henriques, A, Hebrard, C, Higon, E, Holik, P, Holmgren, S, Hruska, I, Huston, J, Jon-And, K, Kakurin, S, Karyukhin, A, Khubua, J, Kopikov, S, Krivkova, P, Kukhtin, V, Kulchitsky, Y, Kuzmin, M, Lami, S, Lapin, V, Lazzeroni, C, Lebedev, A, Leitner, R, Li, J, Lomakin, Y, Lomakina, O, Lokajicek, M, Lopez Amengual, JM, Maio, A, Malyukov, S, Marroquin, F, Mataix, L, Mazzoni, E, Merritt, F, Miller, R, and Minashvili, I

Subjects
Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The energy loss spectrum of 180 GeV muons has been measured with the 5.6 m long finely segmented Module 0 of the ATLAS hadron Tile Calorimeter at the CERN SPS. The differential probability dP/dv per radiation length of a fractional energy loss v = ΔΕμ/Εμ has been measured in the range 0.025 ≤ v ≤ 0.97; it is compared with theoretical predictions for energy losses due to bremsstrahlung, production of electron-positron pairs, and energetic knock-on electrons. The iron elastic form factor correction ΔelFe = 1.63 ± 0.17stat ± 0.23Syst±0.200.14theor to muon bremsstrahlung in the region of no screening of the nucleus by atomic electrons has been measured for the first time, and is compared with different theoretical predictions.

Published
2001

19. Measurement of pion and proton response and longitudinal shower profiles up to 20 nuclear interaction lengths with the ATLAS Tile calorimeter

Author

Adragna, P., Alexa, C., Anderson, K., Antonaki, A., Arabidze, A., Batkova, L., Batusov, V., Beck, H.P., Bergeaas Kuutmann, E., Biscarat, C., Blanchot, G., Bogush, A., Bohm, C., Boldea, V., Bosman, M., Bromberg, C., Budagov, J., Burckhart-Chromek, D., Caprini, M., Caloba, L., Calvet, D., Carli, T., Carvalho, J., Cascella, M., Castelo, J., Castillo, M.V., Cavalli-Sforza, M., Cavasinni, V., Cerqueira, A.S., Clement, C., Cobal, M., Cogswell, F., Constantinescu, S., Costanzo, D., Corso-Radu, A., Cuenca, C., Damazio, D.O., Davidek, T., De, K., Del Prete, T., Di Girolamo, B., Dita, S., Djobava, T., Dobson, M., Dotti, A., Downing, R., Efthymiopoulos, I., Eriksson, D., Errede, D., Errede, S., Farbin, A., Fassouliotis, D., Febbraro, R., Fenyuk, A., Ferdi, C., Ferrer, A., Flaminio, V., Francis, D., Fullana, E., Gadomski, S., Gameiro, S., Garde, V., Gellerstedt, K., Giakoumopoulou, V., Gildemeister, O., Gilewsky, V., Giokaris, N., Gollub, N., Gomes, A., Gonzalez, V., Gorini, B., Grenier, P., Gris, P., Gruwe, M., Guarino, V., Guicheney, C., Gupta, A., Haeberli, C., Hakobyan, H., Haney, M., Hellman, S., Henriques, A., Higon, E., Holmgren, S., Hurwitz, M., Huston, J., Iglesias, C., Isaev, A., Jen-La Plante, I., Jon-And, K., Joos, M., Junk, T., Karyukhin, A., Kazarov, A., Khandanyan, H., Khramov, J., Khubua, J., Kolos, S., Korolkov, I., Krivkova, P., Kulchitsky, Y., Kurochkin, Yu., Kuzhir, P., Le Compte, T., Lefevre, R., Lehmann, G., Leitner, R., Lembesi, M., Lesser, J., Li, J., Liablin, M., Lokajicek, M., Lomakin, Y., Lupi, A., Maidanchik, C., Maio, A., Makouski, M., Maliukov, S., Manousakis, A., Mapelli, L., Marques, C., Marroquim, F., Martin, F., Mazzoni, E., Merritt, F., Miagkov, A., Miller, R., Minashvili, I., Miralles, L., Montarou, G., Mosidze, M., Myagkov, A., Nemecek, S., Nessi, M., Nodulman, L., Nordkvist, B., Norniella, O., Novakova, J., Onofre, A., Oreglia, M., Pallin, D., Pantea, D., Petersen, J., Pilcher, J., Pina, J., Pinhão, J., Podlyski, F., Portell, X., Poveda, J., Pribyl, L., Price, L.E., Proudfoot, J., Ramstedt, M., Richards, R., Roda, C., Romanov, V., Rosnet, P., Roy, P., Ruiz, A., Rumiantsev, V., Russakovich, N., Saltó, O., Salvachua, B., Sanchis, E., Sanders, H., Santoni, C., Saraiva, J.G., Sarri, F., Satsunkevitch, I., Says, L.-P., Schlager, G., Schlereth, J., Seixas, J.M., Selldèn, B., Shalanda, N., Shevtsov, P., Shochet, M., Silva, J., Da Silva, P., Simaitis, V., Simonyan, M., Sissakian, A., Sjölin, J., Solans, C., Solodkov, A., Soloviev, I., Solovyanov, O., Sosebee, M., Spanò, F., Stanek, R., Starchenko, E., Starovoitov, P., Stavina, P., Suk, M., Sykora, I., Tang, F., Tas, P., Teuscher, R., Tokar, S., Topilin, N., Torres, J., Tremblet, L., Tsiareshka, P., Tylmad, M., Underwood, D., Unel, G., Usai, G., Valero, A., Valkar, S., Valls, J.A., Vartapetian, A., Vazeille, F., Vichou, I., Vinogradov, V., Vivarelli, I., Volpi, M., White, A., Zaitsev, A., Zenine, A., and Zenis, T.

Published
2010
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20. Testbeam studies of production modules of the ATLAS Tile Calorimeter

Author

Adragna, P., Alexa, C., Anderson, K., Antonaki, A., Arabidze, A., Batkova, L., Batusov, V., Beck, H.P., Bednar, P., Bergeaas Kuutmann, E., Biscarat, C., Blanchot, G., Bogush, A., Bohm, C., Boldea, V., Bosman, M., Bromberg, C., Budagov, J., Burckhart-Chromek, D., Caprini, M., Caloba, L., Calvet, D., Carli, T., Carvalho, J., Cascella, M., Castelo, J., Castillo, M.V., Cavalli-Sforza, M., Cavasinni, V., Cerqueira, A.S., Clement, C., Cobal, M., Cogswell, F., Constantinescu, S., Costanzo, D., Corso-Radu, A., Cuenca, C., Damazio, D.O., David, M., Davidek, T., De, K., Del Prete, T., Di Girolamo, B., Dita, S., Djobava, T., Dobson, M., Dolejsi, J., Dolezal, Z., Dotti, A., Downing, R., Efthymiopoulos, I., Eriksson, D., Errede, D., Errede, S., Farbin, A., Fassouliotis, D., Febbraro, R., Fedorko, I., Fenyuk, A., Ferdi, C., Ferrer, A., Flaminio, V., Francis, D., Fullana, E., Gadomski, S., Gameiro, S., Garde, V., Gellerstedt, K., Giakoumopoulou, V., Gildemeister, O., Gilewsky, V., Giokaris, N., Gollub, N., Gomes, A., Gonzalez, V., Gorini, B., Grenier, P., Gris, P., Gruwe, M., Guarino, V., Guicheney, C., Gupta, A., Haeberli, C., Hakobyan, H., Haney, M., Hellman, S., Henriques, A., Higon, E., Holmgren, S., Hurwitz, M., Huston, J., Iglesias, C., Isaev, A., Jen-La Plante, I., Jon-And, K., Joos, M., Junk, T., Karyukhin, A., Kazarov, A., Khandanyan, H., Khramov, J., Khubua, J., Kolos, S., Korolkov, I., Krivkova, P., Kulchitsky, Y., Kurochkin, Yu, Kuzhir, P., Le Compte, T., Lefevre, R., Lehmann, G., Leitner, R., Lembesi, M., Lesser, J., Li, J., Liablin, M., Lokajicek, M., Lomakin, Y., Lupi, A., Maidanchik, C., Maio, A., Makouski, M., Maliukov, S., Manousakis, A., Mapelli, L., Marques, C., Marroquim, F., Martin, F., Mazzoni, E., Merritt, F., Miagkov, A., Miller, R., Minashvili, I., Miralles, L., Montarou, G., Mosidze, M., Myagkov, A., Nemecek, S., Nessi, M., Nodulman, L., Nordkvist, B., Norniella, O., Onofre, A., Oreglia, M., Pallin, D., Pantea, D., Petersen, J., Pilcher, J., Pina, J., Pinhão, J., Podlyski, F., Portell, X., Poveda, J., Pribyl, L., Price, L.E., Proudfoot, J., Ramstedt, M., Richards, R., Roda, C., Romanov, V., Rosnet, P., Roy, P., Ruiz, A., Rumiantsev, V., Russakovich, N., Saltó, O., Salvachua, B., Sanchis, E., Sanders, H., Santoni, C., Santos, J., Saraiva, J.G., Sarri, F., Satsunkevitch, I., Says, L.-P., Schlager, G., Schlereth, J., Seixas, J.M., Selldèn, B., Shalanda, N., Shevtsov, P., Shochet, M., Silva, J., Da Silva, P., Simaitis, V., Simonyan, M., Sissakian, A., Sjölin, J., Solans, C., Solodkov, A., Soloviev, I., Solovyanov, O., Sosebee, M., Spanò, F., Stanek, R., Starchenko, E., Starovoitov, P., Stavina, P., Suk, M., Sykora, I., Tang, F., Tas, P., Teuscher, R., Tokar, S., Topilin, N., Torres, J., Tremblet, L., Tsiareshka, P., Tylmad, M., Underwood, D., Unel, G., Usai, G., Valero, A., Valkar, S., Valls, J.A., Vartapetian, A., Vazeille, F., Vichou, I., Vinogradov, V., Vivarelli, I., Volpi, M., White, A., Zaitsev, A., Zenine, A., and Zenis, T.

Published
2009
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29. Neutron collimation with microchannel plates: calibration of existing technology and near future possibilities

Author

Tremsin, Anton S., Hussey, Daniel S., Downing, R. Gregory, Feller, W. Bruce, Mildner, David F.R., Jacobson, David L., Arif, Muhammad, and Siegmund, Oswald H.W.

Subjects
Collimators (Optical instrument) -- Analysis, Neutrons -- Scattering, Neutrons -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

A new type of high performance and compact neutron collimator can be manufactured from Gd- or B-doped microchannel plates (MCPs). Structures only a few mm thick have very narrow rocking curves and high out-of-angle rejection ratios, as observed previously with a cold neutron beam. We present the results of measurements with a collimated (L/D ratio ~ 280 : 1) thermal neutron beam. MCP collimators doped with 3 mole % of [sup.nat][Gd.sub.2][O.sub.3] as well as doped with 10 mole % of [sup.10][B.sub.2][O.sub.3] were calibrated for transmission versus tilt angle. The MCPs used in this study were only 0.6 and 0.8 mm thick with ~ 8.5 [micro]m circular pores on 11.5 [micro]m centers. All the measured rocking curves agree well with the theoretically predicted performance. Both experimental and modeling results indicate that very efficient MCP collimators (with < 0.1[degrees] wide rocking curves and a rejection ratio exceeding [10.sup.3]) can be built with the existing technology. The possibility to manufacture collimators with very large L/D ratios exceeding 1000:1 is also discussed for the case of unetched MCPs. The peak transmission of such devices with very sharp rocking curves will be limited to ~ 40 % by the transmission of the undoped glass. Application of MCP collimators for scatter rejection in neutron radiography is also considered in terms of possible image distortions, which are shown to occur only for the systems with detector spatial resolution better than 20 [micro]m FWHM. Index Terms--Collimators, neutron optics, neutron scattering.

Published
2007

32. Very compact high performance microchannel plate thermal neutron collimators

Author

Tremsin, Anton S., Mildner, David F.R., Feller, W. Bruce, and Downing, R. Gregory

Subjects
Nuclear physics -- Research, Optical instruments, Business, Electronics, Electronics and electrical industries
Abstract

In most neutron scattering experiments and in boron neutron capture therapy, the angular spread of the neutron beam is defined by the quality of the neutron collimator. A typical collimator consists of a large number of parallel plates coated with neutron absorbing material, and at present these plates are at least few centimeters in length. In order to obtain collimation in both vertical and horizontal planes, two orthogonally aligned collimators are installed in the neutron beam. We present a new type of high performance neutron collimator made with Gd-doped microchannel plates (MCPs). Such collimators are only few millimeters thick and the rocking curve is expected to be even sharper than that of conventional 0.5[degrees] collimators. While collimation is performed in two perpendicular planes simultaneously, the geometry of these new collimators can be changed so that the degree of collimation in each direction is controlled independently. The modeling of the proposed collimator indicates that for the existing MCP technology the rocking curve can be made as sharp as 0.2[degrees] FWHM, which can be further improved by current developments in the MCP technology. The preliminary experimental evaluation of our first very thin (only 0.6 mm) MCP collimators confirms the accuracy of our numerical model. Index Terms--Collimators, neutron optics.

Published
2004

33. Analytical methods: improvements, advancements and new horizons

Author

Keen, Carl L., Jue, Thomas, Tran, Cuong D., Vogel, John, Downing, R. Gregory, Iyengar, Venkatesh, and Rucker, Robert B.

Subjects
Trace analysis -- Methods, Trace elements in nutrition -- Analysis, Food/cooking/nutrition
Abstract

The workshop and exhibits dealing with analytical methods were selected to highlight the current state of the art in elemental analysis. The presentations in the first part of the workshop described approaches and advances important to the analysis of trace minerals. These presentations included: 1) two approaches to mass spectrometry, inductively coupled plasma and accelerator mass spectrometry; 2) use of nuclear magnetic resonance in studies of mineral function; and 3) the use and limitations of fluorescent probes in studies of metal uptake and regulation. In the second part of the workshop, the International Atomic Energy's contributions to nutritional 'metrology' were described. Advances in instrumentation over the past decade have led to extraordinary improvements in the precision and sensitivity of mineral analyses. The ability to address isotopic speciation at such low levels sets the stage for numerous novel approaches in the assessment of trace mineral function. KEY WORDS: * fluorescent probes * nuclear magnetic resonance * inductively coupled plasma-mass spectrometry * accelerator mass spectrometry * metrology

Published
2003

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