scholarly journals A High Efficiency Cosmic Ray Veto for the Mu2e Experiment

2017 ◽  
Author(s):  
E. Dukes ◽  
Ralf Ehrlich ◽  
Keyword(s):  
High Efficiency ◽  
Cosmic Ray

scholarly journals Gamma-ray astrophysics in the MeV range

2021 ◽  
Author(s):  
Alessandro De Angelis ◽  
Vincent Tatischeff ◽  
Andrea Argan ◽  
Søren Brandt ◽  
Andrea Bulgarelli ◽  
...  
Keyword(s):  
High Efficiency ◽  
Gamma Ray ◽  
Earth Science ◽  
Technological Development ◽  
Cosmic Ray ◽  
Space Mission ◽  
Compact Objects ◽  
Medium Size ◽  
Cosmic Ray Interactions ◽  
Silicon Microstrip Detectors

AbstractThe energy range between about 100 keV and 1 GeV is of interest for a vast class of astrophysical topics. In particular, (1) it is the missing ingredient for understanding extreme processes in the multi-messenger era; (2) it allows localizing cosmic-ray interactions with background material and radiation in the Universe, and spotting the reprocessing of these particles; (3) last but not least, gamma-ray emission lines trace the formation of elements in the Galaxy and beyond. In addition, studying the still largely unexplored MeV domain of astronomy would provide for a rich observatory science, including the study of compact objects, solar- and Earth-science, as well as fundamental physics. The technological development of silicon microstrip detectors makes it possible now to detect MeV photons in space with high efficiency and low background. During the last decade, a concept of detector (“ASTROGAM”) has been proposed to fulfil these goals, based on a silicon hodoscope, a 3D position-sensitive calorimeter, and an anticoincidence detector. In this paper we stress the importance of a medium size (M-class) space mission, dubbed “ASTROMEV”, to fulfil these objectives.

ON POSSIBILITY OF SHORT‐TERM PROGNOSIS OF CYCLONIC ACTIVITY AFTER‐EFFECTS IN VILNIUS BY VARIATION OF HARD COSMIC RAY FLUX/CIKLONŲ AKTYVUMO PASEKMIŲ TRUMPALAIKĖS PROGNOZĖS GALIMYBĖS VILNIAUS MIESTE PAGAL KIETOSIOS KOSMINĖS SPINDULIUOTĖS SRAUTO VARIACIJAS/ О ВОЗМОЖНОСТИ КРАТКОВРЕМЕННОГО ПРОГНОЗА ПОСЛЕДСТВИЙ ЦИКЛОНИЧЕСКОЙ АКТИВНОСТИ В ВИЛЬНЮСЕ ПО КОЛЕБАНИЯМ ПОТОКА ЖЕСТКОГО ИЗЛУЧЕНИЯ

2008 ◽  
Vol 16 (4) ◽  
pp. 159-167 ◽  
Author(s):  
Dmitrijus Styra ◽  
Algirdas Čiučelis ◽  
Ana Usovaitė ◽  
Jovita Damauskaitė
Keyword(s):  
Atmospheric Pressure ◽  
High Efficiency ◽  
Cosmic Ray ◽  
Energy Interval ◽  
Time Interval ◽  
Time Intervals ◽  
After Effects ◽  
Minimum Pressure ◽  
Hard Cosmic Ray Flux ◽  
Cosmic Ray Flux

Analysis of hard cosmic ray flux (HCRF) variation at an energy interval 1.2—1.6 MeV was carried out in Vilnius. Connection between HCRF decrease at the mentioned energy interval and the minimum atmospheric pressure in 3–6 days is defined. This phenomenon is registered from 8 up to 13 hours. According to the time interval of HCRF decrease, for instance 8–9 and 9–10 hours, the minimum pressure in Vilnius takes place in 3^1 days, and at time intervals 11–12, and 12–13 hours ‐ in 5–6 days. Realization of this prognosis at one of the presented time intervals was 56–67% in 2002–2003. The same investigation results, with the assumption of atmospheric pressure decrease from 1005 hPa and less, showed a high efficiency of prognosis of the minimum pressure in Vilnius at all the time intervals during 6 days ‐ 92%, and 82% in 2002 and 2003, correspondingly. Santrauka Atlikta kietosios kosminės spinduliuotės srauto variacijų analizė energijų intervale 1,2–1,6 MeV Vilniaus mieste. Nustatytas ryšis tarp kietosios kosminės spinduliuotės srauto (KKSS) sumažėjimo šiame intervale ir atmosferos slėgio kitimo, kuris įvyks per 3–4 paras. Toks ryšis registruojamas tik nuo 8 val. iki 13 val. KKSS mažėjimas Vilniaus mieste priklauso nuo laiko intervalo, pvz., nuo 8–9 ir 9–10 val. slėgis sumažėja po 3–4 dienų; 11–12 ir 12–13 val. slėgis sumažėja po 5–6 dienų. Prognozės efektyvumas viename iš laiko intervalų buvo nuo 56–67 % 2002–2003 m. atitinkamai. To paties tyrimo rezultatai, įskaitant ir atmosferos slėgio mažėjimą nuo 1005 hPa ir mažiau, parodė aukštą prognozės efektyvumą visuose laiko intervaluose per 6 dienas – 92 % ir 82 % 2002–2003 metais atitinkamai. Резюме Проведен анализ колебаний потока жесткого космического излучения (ПЖКИ) в энергетическом интервале 1,2– 1,6 МэВ в г. Вильнюсе. Установлена связь между падением ПЖКИ в этом энергетическом интервале и изменением атмосферного давления, которое произойдет через 3–6 суток. Такая связь регистрируется только с 8 час. до 13 часов. В зависимости от интервала времени регистрации падения ПЖКИ, в частности, 8–9 часов, 9–10 часов – наименьшее давление в г. Вильнюсе образуется через 3–4 суток, а 11–12 часов и 12–13 часов – через 5–6 суток. Выполнимость такого прогноза по падению ПЖКИ в одном временном интервале в среднем соответствовала 56– 67% в 2002–2003 гг. Результаты аналогичного исследования с учетом того, что атмосферное давление уменьшается, начиная с 1005 гПа и ниже, показали высокую эффективность прогноза формирования наименьшего давления в г. Вильнюсе по падению ПЖКИ во всех временных интервалах в течение 6 суток – 92% и 82% в 2002 и 2003 гг. соответственно.

scholarly journals Muons as a tool for background rejection in imaging atmospheric Cherenkov telescope arrays

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
L. Olivera-Nieto ◽  
A. M. W. Mitchell ◽  
K. Bernlöhr ◽  
J. A. Hinton
Keyword(s):  
Gamma Rays ◽  
High Efficiency ◽  
Computing Time ◽  
Cosmic Ray ◽  
Ground Level ◽  
Cherenkov Light ◽  
High Background ◽  
Cherenkov Telescope ◽  
Background Rejection ◽  
Telescope Arrays

AbstractThe presence of muons in air-showers initiated by cosmic ray protons and nuclei is well established as a powerful tool to separate such showers from those initiated by gamma rays. However, so far this approach has been fully exploited only for ground level particle detecting arrays. We explore the feasibility of using Cherenkov light from muons as a background rejection tool for imaging atmospheric Cherenkov telescope arrays at the highest energies. We adopt an analytical model of the Cherenkov light from individual muons to allow rapid simulation of a large number of showers in a hybrid mode. This allows us to explore the very high background rejection power regime at acceptable cost in terms of computing time. We show that for very large ($$\gtrsim 20$$ ≳ 20  m mirror diameter) telescopes, efficient identification of muon light can potentially lead to background rejection levels up to 10$$^{-5}$$ - 5 whilst retaining high efficiency for gamma rays. While many challenges remain in the effective exploitation of the muon Cherenkov light in the data analysis for imaging Cherenkov telescope arrays, our study indicates that for arrays containing at least one large telescope, this is a very worthwhile endeavor.

scholarly journals ON CONNECTION OF VARIATIONS BETWEEN HARD COSMIC RAY FLUX, TEMPERATURE AND CARDIOVASCULAR DISEASES IN VILNIUS AND SUNSPOT NUMBER DURING 2001–2012

2015 ◽  
Vol 23 (2) ◽  
pp. 113-120
Author(s):  
Dmitrijus STYRO ◽  
Ana USOVAITE
Keyword(s):  
Cardiovascular Diseases ◽  
Correlation Coefficient ◽  
Sunspot Number ◽  
Air Temperature ◽  
High Efficiency ◽  
Cosmic Ray ◽  
Annual Data ◽  
Short Term ◽  
Hard Cosmic Ray Flux ◽  
Cosmic Ray Flux

The connection has been found between the course of cardiovascular diseases (CVD) and the hard cosmic ray flux (HCRF) near the ground surface in Vilnius. The course of air temperature and number of sunspot was simultaneously considered. The investigation was carried out for the average annual and average monthly values in the period of solar cycle 2001–2012. The course of average annual data is most identical for HCRF and number of sunspot: whereas, it significantly differs from CVD and temperature course. The stable connection between a course of average monthly values of HCRF and CVD is found. Such a connection for temperature and CVD had a negative correlation with coefficient of correlation –0.9. A rather weak correlation was between the change in the number of sunspots another characteristics. Values of correlation coefficient between them were less than 0.4 during all of the solar cycle2001–2012. The exception had taken place at the maximum solar activity, i. e. in 2001 and 2012 when values of correlation coefficient exceeded 0.5. For the short-term prognosis of CVD leaps exceeding average monthly value by 10%in 1–3 days after HCRF decrease according to the proposed criterion, the high efficiency of the results 68–79% was obtained. The variation of sunspot number isn’t connected with these data. A short-term connection between the change in air temperature, the change in the sunspot number and CVD leaps has not been found. The human factor has an additional influence on CVD leaps, which was considered in these studies.

A Very High Efficiency Neutron Counter for the Measurement of Plutonium in Decommissioning Wastes

2003 ◽  
Author(s):  
A. C. Tolchard ◽  
M. R. Looman ◽  
J. A. Mason
Keyword(s):  
High Efficiency ◽  
Operating Experience ◽  
Cosmic Ray ◽  
Shift Register ◽  
Research Centre ◽  
Neutron Counter ◽  
Coincidence Counting ◽  
Counting Mode ◽  
Very High ◽  
Fast Detector

The design of the ANTECH Model 2203 Very High Efficiency Neutron Counter (V-HENC) is a natural progression from the well-proven ANTECH Series 2200 Passive Neutron Drum Monitor used for measuring plutonium in intermediate and low level waste (LLW) 200 litre drums. ANTECH has had considerable experience in the implementation of the base design, originally licensed to ANTECH from the Joint Research Centre at Ispra, Italy. Three Series 2200 systems have been supplied by ANTECH: two are in operation at AWE Aldermaston for waste monitoring, and a third is implemented at the SMP facility at BNFL Sellafield. Some 15 years cumulative operating experience has been gained, and ANTECH provides technical support as part of continuing maintenance and support arrangements. The design has proven to be inherently reliable, safe, easy to operate and maintain. Recently, both AWE instruments have been fully characterised and calibrated to function in conventional coincidence counting mode with calibrations. ANTECH has used MCNP to optimise the design of the fast detector packages in order to achieve the lower detection levels required to measure Pu at USA TRU/LLW and UK Nirex LLW levels. With the aid of simulations a typical detection efficiency of 36% with Cd filters deployed and up to 45% with the internal Cd liner removed has been achieved. Statistical data filtering is used to decrease the cosmic ray induced neutron background, the latter also being minimised by the absence of steelwork within the drum measurement chamber. An outer shielding of 270 mm thickness of polyethylene is used to shield the system from external neutrons. A total of 16 fast detector modules are used, which consist of eight, 7.5 atmospheres 3He tubes (25.4mm diameter and 1033 mm active length) embedded in high density polyethylene and arranged in a double row. Tubes are connected using HN connectors to a junction box at the top of the vertical modules or on the end of the horizontal modules. The junction boxes are hermetically sealed and contain the high voltage distribution and AMPTEK model A-111 charge sensitive amplifiers. The operation of the V-HENC is based on passive neutron counting of the correlated neutrons from spontaneous fission of the even Pu nuclides, principally 240Pu and is coupled with an ANTECH/Ortec Advanced Multiplicity Shift Register employing the Los Alamos INCC code. Alternatively, the multiple gate ANTECH Time Correlation Analyser (TCA) may be used for enhanced data acquisition for multiplicity counting. The V-HENC can be operated in conventional shift register coincidence counting (Reals) mode (with a calibration function), the absolute multiplicity counting mode (histogram function) or totals counting mode. Plant measured isotopic ratios can be used by the software to convert 240Pueffective mass to total Pu mass.

scholarly journals Metamorphism of Cosmic Dust: Diagnostic Infrared Signatures

1992 ◽  
Vol 150 ◽  
pp. 39-40
Author(s):  
Joseph A. Nuth
Keyword(s):  
Absorption Band ◽  
Gas Phase ◽  
High Efficiency ◽  
Driving Forces ◽  
Cosmic Ray ◽  
High Energy ◽  
Laboratory Studies ◽  
Continuous Increase ◽  
Relative Age ◽  
Equilibrium Process

Nucleation is a non-equilibrium process: the products of this process are seldom the most thermodynamically stable condensates but are instead those which form fastest. It should not be surprising that grains formed in a circumstellar outflow will undergo some degree of metamorphism if they are annealed or exposed to a chemically active reagent. As a consequence of this processing in the laboratory one observes a continuous increase in the strength of the silicate absorption band at 20 microns relative to the 10 micron feature. In Section 1 we show that this ratio can be used as an indicator of the relative age of silicate condensates. Metamorphism of refractory particles continues in the interstellar medium (ISM) where the driving forces are sputtering by cosmic ray particles, annealing by high energy photons and grain destruction in supernova generated shocks. Studies of the depletion of the elements from the gas phase of the ISM tell us that if grain destruction occurs with high efficiency, then there must be some mechanism by which grains can be formed in the ISM. Laboratory studies of such a process (Moore, Tanabe, and Nuth, Ap. J. (Lett) 373, L31-L34, 1990) have shown that the frequency of the -SiH stretch can be used as an indicator of the oxidation state of the silicon in such grains. Highly reduced grains exhibit an SiH absorption near 2100 cm−1 whereas highly oxidized silicates absorb near 2300 cm−1: this point is discussed in Section 2.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

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