Sample records for sns cryomodule performance
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International Nuclear Information System (INIS)
Isidoro Campisi; Edward Daly; G. Davis; Jean Delayen; Michael Drury; Christiana Grenoble; John Hogan; Lawrence King; Peter Kneisel; John Mammosser; Thomas Powers; Joseph Preble; Mircia Stirbet; Haipeng Wang; Tim Whitlatch; Mark Wiseman
2003-01-01
Thomas Jefferson National Accelerating Facility, Jefferson Lab, is producing 24 Superconducting Radio FR-equency (SRF) cryomodules for the Spallation Neutron Source (SNS) cold linac. This includes one medium beta (0.61) prototype, 11 medium beta production, and 12 high beta (0.81) production cryomodules. After testing [ ], the medium beta prototype cryomodule was shipped to Oak Ridge National Laboratory (ORNL) and acceptance check out has been completed. All production orders for cavities and cryomodule components are being received at this time and the medium beta cryomodule production run has started. Each of the medium beta cryomodules is scheduled to undergo complete operational performance testing at Jefferson Laboratory before shipment to ORNL. The performance results of cryomodules to date will be discussed
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Overview of SNS Cryomodule Performance
Drury, Michael A; Davis, Kirk; Delayen, Jean R; Grenoble, Christiana; Hicks, William R; King, Larry; Plawski, Tomasz; Powers, Tom; Preble, Joseph P; Wang, Haipeng; Wiseman, Mark
2005-01-01
Thomas Jefferson National Accelerating Facility (Jefferson Lab) has completed production of 24 Superconducting Radio Frequency (SRF) cryomodules for the Spallation Neutron Source (SNS) superconducting linac. This includes one medium-beta (0.61) prototype, eleven medium-beta and twelve high-beta (0.81) production cryomodules. Ten medium-beta cryomodules as well as two high beta cryomodules have undergone complete operational performance testing in the Cryomodule Test Facility at Jefferson Lab. The set of tests includes measurements of maximum gradient, unloaded Q (Q0), microphonics, and response to Lorentz forces. The Qext's of the various couplers are measured and the behavior of the higher order mode couplers is examined. The mechanical and piezo tuners are also characterized. The results of these performance tests will be discussed in this paper.
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Overview of SNS Cryomodule Performance
International Nuclear Information System (INIS)
Michael Drury; Edward Daly; Christiana Grenoble; William Hicks; Lawrence King; Tomasz Plawski; Thomas Powers; Joseph Preble; Haipeng Wang; Mark Wiseman; G. Davis; Jean Delayen
2005-01-01
Thomas Jefferson National Accelerating Facility (Jefferson Lab) has completed production of 24 Superconducting Radio Frequency (SRF) cryomodules for the Spallation Neutron Source (SNS) superconducting linac. This includes one medium-β (0.61) prototype, eleven medium-β and twelve high-β (0.81) production cryomodules. Nine medium-β cryomodules as well as two high-β cryomodules have undergone complete operational performance testing in the Cryomodule Test Facility at Jefferson Lab. The set of tests includes measurements of maximum gradient, unloaded Q (Q 0 ), microphonics, and response to Lorentz forces. The Q ext 's of the various couplers are measured and the behavior of the higher order mode couplers is examined. The mechanical and piezo tuners are also characterized. The results of these performance tests will be discussed in this paper
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Lessons Learned from the Jefferson Lab - SNS Cryomodule Production Run
International Nuclear Information System (INIS)
John Hogan; Edward Daly; John Fischer; Joseph Preble
2005-01-01
In light of the recent developments with the International Linear Collider (ILC), and the recommendation to utilize ''Cold'' technology for this future particle accelerator, this paper will present the lessons learned from the recently concluded Spallation Neutron Source (SNS) superconducting radio frequency (SRF) cryomodule production run at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). Over the past twenty years Jefferson Lab has worked with industry to successfully design, manufacture, test and commission more SRF cryomodules than any other entity in the United States. The knowledge gained from the design and fabrication of the SNS prototype, eleven - 0.61 (medium) beta and the twelve - 0.81 (high) beta cryomodules, will prove to be an effective asset to the ILC project. After delivery of the final production cryomodule in March 2005, design and fabrication data will be collected, evaluated and presented to make this information beneficial for future particle accelerator projects. Recommendations with respect to these findings will also be presented as an integral part of this paper
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Hogan, John; Daly, Edward; Drury, Michael A; Fischer, John; Hiatt, Tommy; Kneisel, Peter; Mammosser, John; Preble, Joseph P; Whitlatch, Timothy; Wilson, Katherine; Wiseman, Mark
2005-01-01
This paper will discuss the technology transfer aspect of superconducting RF expertise, as it pertains to cryomodule production, beginning with the original design requirements through testing and concluding with product delivery to the end user. The success of future industrialization, of accelerator systems, is dependent upon a focused effort on accelerator technology transfer. Over the past twenty years the Thomas Jefferson National Accelerator Facility (Jefferson Lab) has worked with industry to successfully design, manufacture, test and commission more superconducting RF cryomodules than any other entity in the United States. The most recent accomplishment of Jefferson Lab has been the successful production of twenty-four cryomodules designed for the Spallation Neutron Source (SNS). Jefferson Lab was chosen, by the United States Department of Energy, to provide the superconducting portion of the SNS linac due to its reputation as a primary resource for SRF expertise. The successful partnering with, and d...
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Analysis of the Qualification-Tests Performance of the Superconducting Cavities for the SNS Linac
Delayen, J R; Ozelis, O
2004-01-01
Thomas Jefferson National Accelerating Facility (Jefferson Lab) is producing superconducting radio frequency (SRF) cryomodules for the Spallation Neutron Source (SNS) cold linac. This consists of 11 medium-beta (β=0.61) cyomodules of 3 cavities each, and 12 high-beta (β=0.81) cryomodules of 4 cavities each. Before assembly into cavity strings the cavities undergo individual qualification tests in a vertical cryostat (VTA). In this paper we analyze the performance of the cavities during these qualification tests, and attempt to correlate this performance with cleaning, assembly, and testing procedures. We also compare VTA performance with performance in completed cryomodules.
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Superconducting Magnet Performance in LCLS-II Cryomodules
Energy Technology Data Exchange (ETDEWEB)
Kashikhin, V. [Fermilab; Cheban, S. [Fermilab; DiMarco, J. [Fermilab; Harms, E. [Fermilab; Makarov, A. [Fermilab; Strauss, T. [Fermilab; Tartaglia, M. [Fermilab
2018-04-01
New LCLS-II Linear Superconducting Accelerator Cry-omodules are under construction at Fermilab. Installed in-side each SCRF Cryomodule is a superconducting magnet package to focus and steer an electron beam. The magnet package is an iron dominated configuration with conduc-tively cooled racetrack-type quadrupole and dipole coils. For easier installation the magnet can be split in the vertical plane. Initially the magnet was tested in a liquid helium bath, and high precision magnetic field measurements were performed. The first (prototype) Cryomodule with the magnet inside was built and successfully tested at Fermilab test facility. In this paper the magnet package is discussed, the Cryomodule magnet test results and current leads con-duction cooling performance are presented. So far magnets in nine Cryomodules were successfully tested at Fermilab.
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International Nuclear Information System (INIS)
Sundelin, Ronald M.
2001-01-01
The Spallation Neutron Source (SNS) decided in early 2000 to use superconducting RF (SRF) in the linac at energies above 185 MeV. Since the SNS duty cycle is 6%, the SRF and normal conducting approaches have capital costs which are about the same, but operating costs and future upgradability are improved by using SRF. The current status of cavity and cryomodule development and procurement, including the basis for decisions made, is discussed. The current plan includes use of 805 MHz, 6-cell cavities with geometrical betas of 0.61 and 0.81. There are 33 medium beta and 60 high beta cavities in 11 and 15 cryomodules, respectively. Each cavity (except the 93rd) is powered by a 550 kW pulsed klystron. Issues addressed include choice of peak surface gradient, optimization of cavity shape, selection of a scaled KEK input power coupler, selection of scaled TESLA higher mode couplers, and control of the effects of higher order modes on the beam. (author)
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RF Processing of the Couplers for the SNS Superconducting Cavities
International Nuclear Information System (INIS)
Y.Kang; I.E. Campisi; D. Stout; A. Vassioutchenko; M. Stirbet; M. Drury; T. Powers
2005-01-01
All eighty-one fundamental power couplers for the 805 MHz superconducting cavities of the SNS linac have been RF conditioned and installed in the cryomodules successfully. The couplers were RF processed at JLAB or at the SNS in ORNL: more than forty couplers have been RF conditioned in the SNS RF Test Facility (RFTF) after the first forty couplers were conditioned at JLAB. The couplers were conditioned up to 650 kW forward power at 8% duty cycle in traveling and standing waves. They were installed on the cavities in the cryomodules and then assembled with the airside waveguide transitions. The couplers have been high power RF tested with satisfactory accelerating field gradients in the cooled cavities
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Performance Characterization of LCLS-II Superconducting Radiofrequency Cryomodules
Energy Technology Data Exchange (ETDEWEB)
Gregory, RuthAnn [Michigan State Univ., East Lansing, MI (United States)
2017-11-10
This paper will describe the LCLS (Linac Coherent Light Source)-II, Fermilab’s role in the development of LCLS-II, and my contributions as a Lee Teng intern. LCLS-II is a second generation x-ray free electron laser being constructed at SLAC National Accelerator Laboratory. Fermilab is responsible for the design, construction, and testing of several 1.3 GHz cryomodules to be used in LCLS-II. These cryomodules are currently being tested at Fermilab. Some software was written to analyze the data from the cryomodule tests. This software assesses the performance of the cryomodules by looking at data on the cavity voltage, cavity gradient, dark current, and radiation.
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Low Level RF System for Jefferson Lab Cryomodule Test Facility
International Nuclear Information System (INIS)
Tomasz Plawski; Trent Allison; Jean Delayen; J. Hovater; Thomas Powers
2003-01-01
The Jefferson Lab Cryomodule Test Facility (CMTF) has been upgraded to test and commission SNS and CEBAF Energy Upgrade cryomodules. Part of the upgrade was to modernize the superconducting cavity instrumentation and control. We have designed a VXI based RF control system exclusively for the production testing of superconducting cavities. The RF system can be configured to work either in Phase Locked Loop (PLL) or Self Excited Loop (SEL) mode. It can be used to drive either SNS 805 MHz or CEBAF Energy Upgrade 1497 MHz superconducting cavities and can be operated in pulsed or continuous wave (CW) mode. The base design consists of RF-analog and digital sections. The RF-analog section includes a Voltage Control Oscillator (VCO), phase detector, IandQ modulator and ''low phase shift'' limiter. The digital section controls the analog section and includes ADC, FPGA, and DAC . We will discuss the design of the RF system and how it relates to the support of cavity testing
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THE JLAB AMPERE-CLASS CRYOMODULE CONCEPTUAL DESIGN
International Nuclear Information System (INIS)
Robert Rimmer; Edward Daly; William Hicks; James Henry; Joseph Preble; Mircea Stirbet; Haipeng Wang; Katherine Wilson; Genfa Wu; Gianluigi Ciovati; Thomas Elliott; Peter Kneisel; Stephen Manning; Robert Manus; Karl Smith; Lynn Vogel; Larry Turlington
2006-01-01
For the next generation of compact high-power FELs a new cryomodule is required that is capable of accelerating up to Ampere levels of beam current. Challenges include strong HOM damping, high HOM power and high fundamental-mode power (in operating scenarios without full energy recovery). For efficient use of space a high real-estate gradient is desirable and for economic operation good fundamental-mode efficiency is important. The technology must also be robust and should be based on well-proven and reliable technologies. For Ampere-class levels of beam current both halo interception and beam break-up (BBU) are important considerations. These factors tend to drive the designs to lower frequencies where the apertures are larger and the transverse impedances are lower. To achieve these goals we propose to use a compact waveguide-damped multi-cell cavity packaged in an SNS-style cryomodule
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The Jefferson Lab Quality Assurance Program for the SNS Superconducting Linac Construction Project
International Nuclear Information System (INIS)
Joseph Ozelis
2003-01-01
As part of a multi-laboratory collaboration, Jefferson Lab is currently engaged in the fabrication, assembly, and testing of 23 cryomodules for the superconducting linac portion of the Spallation Neutron Source (SNS) being built at Oak Ridge National Laboratory. As with any large accelerator construction project, it is vitally important that these components be built in a cost effective and timely manner, and that they meet the stringent performance requirements dictated by the project specifications. A comprehensive Quality Assurance (QA) program designed to help accomplish these goals has been implemented as an inherent component of JLab's SNS construction effort. This QA program encompasses the traditional spectrum of component performance, from incoming parts inspection, raw materials testing, through to sub-assembly and finished article performance evaluation
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Commissioning of the Superconducting Linac at the Spallation Neutron Source (SNS)
International Nuclear Information System (INIS)
Kim, Sang-Ho; Campisi, Isidoro E.
2007-01-01
The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H-ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS will use the accelerated short (about 700 ns) sub-bunches of protons to generate neutrons by spallation, which will in turn allow probing structural and magnetic properties of new and existing materials. The SNS superconducting linac is the largest application of RF superconductivity to come on-line in the last decade. The SRF cavities, operated at 805 MHz, were designed, built and integrated into cryomodules at Jefferson Lab and installed and tested at SNS. SNS is also the first proton-like accelerator which uses SRF cavities in a pulse mode. Many of the details of the cavity performance are peculiar to this mode of operation, which is also being applied to lepton accelerators (TESLA test facility and X-FEL at DESY and the international linear collider project). Thanks to the low frequency of the SNS superconducting cavities, operation at 4.2 K has been possible without beam energy degradation, even though the cavities and cryogenic systems were originally designed for 2.1 K operation. The testing of the superconducting cavities, the operating experience with beam and the performance of the superconducting linac will be presented
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Status of the SNS superconducting linac and future plan
International Nuclear Information System (INIS)
Kim, Sang-Ho
2008-01-01
The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H- ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS generates neutrons by the spallation reaction with the accelerated short (about 700 ns) sub-bunches of protons, which will in turn allow probing structural and magnetic properties of new and existing materials. The SNS superconducting linac is the largest application of RF superconductivity to come on-line in the last decade and has been operating with beam for almost two years. As the first operational pulsed superconducting linac, many of the aspects of its performance were unknown and unpredictable. A lot of experiences and data have been gathered on the pulsed behavior of cavities and cryomodules at various repetition rates and at various temperatures during the commissioning of its components and beam operations. This experience is of great value in determining future optimizations of SNS as well in guiding in the design and operation of future pulsed superconducting linacs. The testing of the superconducting cavities, the operating experience with beam, the performance of the superconducting linac and the future plans will be presented.
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Cooling tests of the cryomodules at superconducting RF test facility (STF)
International Nuclear Information System (INIS)
Ohuchi, Norihito; Nakai, Hirotaka; Kojima, Yuuji
2009-01-01
KEK has been constructing the Superconducting RF Test Facility (STF) with aiming at a center of the ILC-R and D in Asia from 2005. In this project, KEK targets manufacturing and operational experiences of the RF cavity and cryomodule toward the ILC, and two cryomodules have been developed. These cryomodules are 6 meter long and have 4 nine-cell cavities in each cryostat. The designs of the cryomodules are based on the TESLA Type-3 (TTF-3) at DESY, however, each cryostat has the different type of cavities, TESLA-like type and Low-Loss type. The tests of the cryomodules were performed in two steps. In the first test, measurements of the cryogenic performances of these cryomodules were the main objective. One nine-cell cavity was assembled in each cryomodule and cool-down of the two cryomodules was performed, individually. In the second test, the four TESLA-like cavities were assembled in the cryomodule as complete integration. Cool-down of the cryomodule to 2 K was successfully completed, and thermal performances of the cryomodule and cooling capacity of the cryogenics system were studied in detail. In this paper, we will report the design of the cryomodules and the thermal performances at these cold tests. (author)
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Energy Technology Data Exchange (ETDEWEB)
Peterson, T. J. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Weisend, II, J. G. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
2016-01-01
The TESLA collaboration developed a unique variant of SRF cryomodule designs, the chief feature being use of the large, low pressure helium vapor return pipe as the structural support backbone of the cryomodule. Additional innovative features include all cryogenic piping within the cryomodule (no parallel external cryogenic transfer line), long strings of RF cavities within a single cryomodule, and cryomodules connected in series. Several projects, including FLASH and XFEL at DESY, LCLS-II at SLAC, and the ILC technical design have adopted this general design concept. Advantages include saving space by eliminating the external transfer line, relatively tight packing of RF cavities along the beamline due to fewer warm-cold transitions, and potentially lower costs. However, a primary disadvantage is the relative lack of independence for warm-up, replacement, and cool-down of individual cryomodules.
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Commissioning of the CEBAF cryomodules
International Nuclear Information System (INIS)
Drury, M.; Lee, T.; Marshall, J.; Preble, J.; Saulter, Q.; Schneider, W.; Spata, M.; Wiseman, M.
1993-01-01
When complete, the Continuous Electron Beam Accelerator Facility will house a 4 GeV recirculating linear accelerator containing 42 1/4 cryomodules arrayed in two antiparallel linacs and an injector. Currently, over half of the cryomodules have been installed. Each cryomodule contains eight superconducting niobium 5-cell rf cavities that operate at 1.497 GHz. A cryomodule must provide an energy gain of 20 MeV to the 200 μA beam. The resultant dynamic heat load must be less than 45 W. The cavity parameters that are measured during the commissioning process include the external Q's of the cavity ports, the unloaded Q (Q 0 ) of the cavity as a function of accelerating gradient, and the maximum operating gradient of the cavity. The sensitivity of the resonant frequency to changes in pressure and gradient is also measured. Finally, the mechanical tuners are cycled and characterized. In all cases, the performance of CEBAF cryomodules has exceeded the design requirements. A portable test stand allows local control of the rf system and provides automated data acquisition. This paper describes the cryomodule commissioning hardware, software, and measurements
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Performance of the FEL cryomodules
International Nuclear Information System (INIS)
Drury, M.; Fischer, J.; Preble, J.
1998-01-01
The Thomas Jefferson National Accelerator Facility (Jefferson Lab, formerly known as CEBAF) is building a highly efficient, kilowatt-level infrared free-electron laser, the IR Demo FEL. The IR FEL uses superconducting radio-frequency (SRF) cavities to accelerate the electron beam that provides energy for the laser. These cavities provide the high-gradient acceleration for the high average currents necessary for a compact FEL design. Currently, a quarter cryomodule injector and a full eight-cavity cryomodule have been installed in the FEL linac. These units were tested as part of the IR FEL commissioning process. The main focus of these tests was to determine the maximum stable operating gradient. The average maximum gradient reached by these ten cavities was 11 Mv/m. Other tests include measurement of cavity parameters such as the unloaded Q (Qo) vs. gradient, the input coupling, calibration of field probes and behavior of the tuner mechanisms. This paper presents the results of those tests
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Alignment of CEBAF cryomodules
International Nuclear Information System (INIS)
Schneider, W.J.; Bisognano, J.J.; Fischer, J.
1993-06-01
CEBAF, the Continuous Electron Beam Accelerator Facility, when completed, will house a 4 GeV recirculating accelerator. Each of the accelerator's two linacs contains 160 superconducting radio frequency (SRF) 1497 MHz niobium cavities in 20 cryomodules. Alignments of the cavities within the cryomodule with respect to beam axis is critical to achieving the optimum accelerator performance. This paper discusses the rationale for the current specification on cavity mechanical alignment: 2 mrad (rms) applied to the 0.5 m active length cavities. We describe the tooling that was developed to achieve the tolerance at the time of cavity pair assembly, to preserve and integrate alignment during cryomodule assembly, and to translate alignment to appropriate installation in the beam line
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LCLS-II Cryomodules Production at Fermilab
Energy Technology Data Exchange (ETDEWEB)
Arkan, Tug [Fermilab; Grimm, Chuck [Fermilab; Kaluzny, Joshua [Fermilab; Orlov, Yuriy [Fermilab; Peterson, Thomas [Fermilab; Premo, Ken [Fermilab
2017-05-01
LCLS-II is an upgrade project for the linear coherent light source (LCLS) at SLAC. The LCLS-II linac will consist of thirty-five 1.3 GHz and two 3.9 GHz superconducting RF continuous wave (CW) cryomodules that Fermilab and Jefferson Lab (JLab) will assemble in collaboration with SLAC. The LCLS-II 1.3 GHz cryomodule design is based on the European XFEL pulsed-mode cryomodule design with modifications needed for CW operation. Fermilab and JLab will each assemble and test a prototype 1.3 GHz cryomodule to assess the results of the CW modifications, in advance of 16 and 17 production 1.3 GHz cryomodules, respectively. Fermilab is solely responsible for the 3.9 GHz cryomodules. After the prototype cryomodule tests are complete and lessons learned incorporated, both laboratories will increase their cryomodule production rates to meet the challenging LCLS-II project requirement of approximately one cryomodule per month per laboratory. This paper presents the Fermilab Cryomodule Assembly Facility (CAF) infrastructure for LCLS-II cryomodule production, the Fermilab prototype 1.3 GHz CW cryomodule (pCM) assembly and readiness for production assembly.
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Commissioning and operation of the horizontal test apparatus at SNS
Energy Technology Data Exchange (ETDEWEB)
Kim, Sang-Ho [ORNL; Neustadt, Thomas S. [ORNL; Howell, Matthew P. [ORNL; Hannah, Brian S. [ORNL; Doleans, Marc [ORNL; Saunders, Jeffrey W. [ORNL
2015-07-01
The Spallation Neutron Source (SNS) at Oak Ridge National Lab (ORNL) has built, commissioned and operated a Horizontal Test Apparatus (HTA) vessel in the Radiofrequency Test Facility (RFTF) test cave. It can be operated at 4.5 K using the independent Cryogenic Test Facility (CTF). The HTA is designed to be a single cavity version of an SNS cryomodule with the ability to demount and replace the cavity. It provides the functionality for testing a single dressed SNS medium or high beta Superconducting Radiofrequency (SRF) cavity. The HTA is currently being used in support of R&D for in-situ plasma processing of the cavity's inner niobium surface. The design and commissioning of the HTA at 4.5 K will be presented as well as results from operating the HTA including cool-down, warm-up and steady state operations. Results from plasma processing a warm SCRF cavity in-between cold HTA tests will also be reported.
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Design and development of cryo-module test system for 1.3 GHz LCLS-II cryomodule
International Nuclear Information System (INIS)
Khunt, A.C.S.; Anupam Kumar Sinha, B.; Aravind, T.C.; Mishra, D.V.K.; Sinha, E.A.K.; Mukesh Goyal, F.; Tejas Rane, G.
2015-01-01
Cryomodule Test System (CMTS) is a major cryogenic system designed and developed at Centre for Design and Manufacture (CDM), BARC under Indian Institutions and Fermi Lab Collaboration (IIFC). It is necessary test bed to measure the performance of superconducting RF cavities in Cryomodule. CMTS is required to test 1.3 GHz LCLS-II Cryomodule for Stanford Linear Accelerator Centre (SLAC), USA. Feed Cap and End Cap sub systems of Cryomodule Test System (CMTS) is designed and developed at CDM, BARC. Feed cap and End cap are 2K liquid helium distribution system for LCLS-II RF Cavity Bath and insulated by intermediate radiation shields maintained at 5K and 40K and Multilayer Insulation. The whole distribution system is enclosed in horizontal vacuum shells of approximately 1100 mm in diameter and 3000 mm in total length. This development was very challenging as many design considerations and decisions for 2K cryogenic requirements have been made and implemented. Also intricate mounting of ceramic sensors both internally and externally (surface mounted) for very low temperature measurements, low temperature epoxy bonding and multi-layer insulation wrapping were successfully completed. (author)
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Thermal Design and Performance results of the first High-Beta Cryo-module for HIE-ISOLDE at CERN
International Nuclear Information System (INIS)
Valdarno, L; Delruelle, N; Leclercq, Y; Parma, V; Vandoni, G; Williams, L
2015-01-01
The High Energy and Intensity HIE-ISOLDE is a facility under construction at CERN whose target is ultimately, after the installation of six cryo-modules, to produce radioactive ion beams at 10MeV/u maximum energy in order to significantly expand the nuclear physics programme carried out by REX-ISOLDE. Since thermal control is essential to the performance of the whole cryo-module, a combination of a passive (materials, coatings, and surface finishes) and active (cryogenic loops, heaters) control has been designed to keep the cryostat operating within the allowable thermal budget. A numerical model based on Finite Element has been developed in order to generate a faithful global mapping of temperatures and heat fluxes inside the cryo-module. The numerical model, combined with the experimental results of the first test campaign, will serve as an optimization tool for the future cryo-modules in terms of improvement in the global and specific heat loads management. (paper)
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Thermal Design and Performance results of the first High-Beta Cryo-module for HIE-ISOLDE at CERN
Valdarno, L; Leclercq, Y; Parma, V; Vandoni, G; Williams, L
2015-01-01
The High Energy and Intensity HIE-ISOLDE is a facility under construction at CERN whose target is ultimately, after the installation of six cryo-modules, to produce radioactive ion beams at 10MeV/u maximum energy in order to significantly expand the nuclear physics programme carried out by REX-ISOLDE. Since thermal control is essential to the performance of the whole cryo-module, a combination of a passive (materials, coatings, and surface finishes) and active (cryogenic loops, heaters) control has been designed to keep the cryostat operating within the allowable thermal budget. A numerical model based on Finite Element has been developed in order to generate a faithful global mapping of temperatures and heat fluxes inside the cryo-module. The numerical model, combined with the experimental results of the first test campaign, will serve as an optimization tool for the future cryo-modules in terms of improvement in the global and specific heat loads management.
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BNL 703 MHz SRF cryomodule demonstration
International Nuclear Information System (INIS)
Burrill, A.; Ben-Zvi, I.; Calaga, R.; Dalesio, L.; Dottavio, T.; Gassner, D.; Hahn, H.; Hoff, L.; Kayran, D.; Kewisch, J.; Lambiase, R.; Lederle, D.; Litvinenko, V.; Mahler, G.; McIntyre, G.
2009-01-01
This paper will present the preliminary results of the testing of the 703 MHz SRF cryomodule designed for use in the ampere class ERL under construction at Brookhaven National Laboratory. The preliminary cavity tests, carried out at Thomas Jefferson Laboratory, demonstrated cavity performance of 20 MV/m with a Qo of 1 x 10 10 , results we expect to reproduce in the horizontal configuration. This test of the entire string assembly will allow us to evaluate all of the additional cryomodule components not previously tested in the VTA and will prepare us for our next milestone test which will be delivery of electrons from our injector through the cryomodule to the beam dump. This will also be the first demonstration of an accelerating cavity designed for use in an ampere class ERL, a key development which holds great promise for future machines
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CEBAF Cryomodule Commissioning in the South Linac
International Nuclear Information System (INIS)
M. Drury; H. Lankford; T. Lee; J. Marshall; J. Preble; Q. Saulter; W. Schneider; Michael Spata; Mark Wiseman
1993-01-01
When complete, the Continuous Electron Beam Accelerator Facility will house a 4 GeV recirculating linear accelerator containing 42 1/4 cryomodules arrayed in two antiparallel linacs and an injector. Currently, 38 1/4 cryomodules have been installed. Each cryomodule contains eight superconducting niobium 5-cell rf cavities that operate at 1.497 GHz[1]. A cryomodule must provide an energy gain of 20 MeV to the 200 mu-A beam[2]. The resultant dynamic heat load must be less than 45 W. The cavity parameters that are measured during the commissioning process include the external Q's (Q(sub ext)) of the cavity ports, the unloaded Q (Q(sub 0)) of the cavity as a function of accelerating gradient, and the maximum operating gradient of the cavity[3]. Finally, the mechanical tuners are cycled and characterized. A portable test stand allows local control of the rf system and provides automated data acquisition. During the period from April 1993 through September 1993, 16 of the 20 cryomodules installed in the South Linac were commissioned. All cryomodules tested in the South Linac meet or exceed the CEBAF specifications. This paper describes the results of the commissioning of the first 10 cryomodules in the South Linac
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Operational Experience from LCLS-II Cryomodule Testing
Energy Technology Data Exchange (ETDEWEB)
Wang, Renzhuo [Fermilab; Hansen, Benjamin [Fermilab; White, Michael [Fermilab; Hurd, Joseph [Fermilab; Atassi, Omar Al [Fermilab; Bossert, Richard [Fermilab; Pei, Liujin [Fermilab; Klebaner, Arkadiy [Fermilab; Makara, Jerry [Fermilab; Theilacker, Jay [Fermilab; Kaluzny, Joshua [Fermilab; Wu, Genfa [Fermilab; Harms, Elvin [Fermilab
2017-07-01
This paper describes the initial operational experience gained from testing Linac Coherent Light Source II (LCLS-II) cryomodules at Fermilab’s Cryomodule Test Facility (CMTF). Strategies for a controlled slow cooldown to 100 K and a fast cooldown past the niobium superconducting transition temperature of 9.2 K will be described. The test stand for the cryomodules at CMTF is sloped to match gradient in the LCLS-II tunnel at Stanford Linear Accelerator (SLAC) laboratory, which adds an additional challenge to stable liquid level control. Control valve regulation, Superconducting Radio-Frequency (SRF) power compensation, and other methods of stabilizing liquid level and pressure in the cryomodule 2.0 K SRF cavity circuit will be discussed. Several different pumping configurations using cold compressors and warm vacuum pumps have been used on the cryomodule 2.0 K return line and the associated results will be described.
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Operational experience from LCLS-II cryomodule testing
Wang, R.; Hansen, B.; White, M.; Hurd, J.; Atassi, O. Al; Bossert, R.; Pei, L.; Klebaner, A.; Makara, J.; Theilacker, J.; Kaluzny, J.; Wu, G.; Harms, E.
2017-12-01
This paper describes the initial operational experience gained from testing Linac Coherent Light Source II (LCLS-II) cryomodules at Fermilab’s Cryomodule Test Facility (CMTF). Strategies for a controlled slow cooldown to 100 K and a fast cooldown past the niobium superconducting transition temperature of 9.2 K will be described. The test stand for the cryomodules at CMTF is sloped to match gradient in the LCLS-II tunnel at Stanford Linear Accelerator (SLAC) laboratory, which adds an additional challenge to stable liquid level control. Control valve regulation, Superconducting Radio-Frequency (SRF) power compensation, and other methods of stabilizing liquid level and pressure in the cryomodule 2.0 K SRF cavity circuit will be discussed. Several different pumping configurations using cold compressors and warm vacuum pumps have been used on the cryomodule 2.0 K return line and the associated results will be described.
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Transport of LCLS-II 1.3 Ghz cryomodule to SLAC
Energy Technology Data Exchange (ETDEWEB)
McGee, M. W.; Arkan, T.; Peterson, T.; Tang, Z.; Boo, S.; Carrasco, M.; Daly, E.; Huque, N.
2016-06-30
In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These include a prototype built and delivered by each Lab. Another two 3.9 GHz cryomodules will be built, tested and transported by Fermilab to SLAC. Each assembly will be transported over-the-road from Fermilab or Jefferson Lab using specific routes to SLAC. The transport system consists of a base frame, isolation fixture and upper protective truss. The strongback cryomodule lifting fixture is described along with other supporting equipment used for both over-the-road transport and local (on-site) transport at Fermilab. Initially, analysis of fragile components and stability studies will be performed in order to assess the risk associated with over-the-road transport of a fully assembled cryomodule.
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LCLS-II 1.3 GHz cryomodule design - lessons learned from testing at Fermilab
Kaluzny, J.; Hurd, J.; Orlov, Y.; He, Y.; Bossert, R.; Grimm, C.; Schappert, W.; Atassi, O. Al; Wang, R.; Arkan, T.; Theilacker, J.; Klebaner, A.; White, M.; Wu, G.; Makara, J.; Ginsburg, C.; Pei, L.; Holzbauer, J.; Hansen, B.; Stanek, R.; Peterson, T.; Harms, E.
2017-12-01
Fermilab’s 1.3 GHz prototype cryomodule for the Linac Coherent Light Source Upgrade (LCLS-II) has been tested at Fermilab’s Cryomodule Test Facility (CMTF). Aspects of the cryomodule design have been studied and tested. The cooldown circuit was used to quickly cool the cavities through the transition temperature, and a heater on the circuit was used to heat incoming helium for warmup. Due to the 0.5% slope of the cryomodule, the liquid level is not constant along the length of the cryomodule. This slope as well as the pressure profile caused liquid level management to be a challenge. The microphonics levels in the cryomodule were studied and efforts were made to reduce them throughout testing. Some of the design approaches and studies performed on these aspects will be presented. Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. This work was supported, in part, by the LCLS-II Project.
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HIE-ISOLDE CRYO-MODULE Assembly - Superconducting Solenoid
Leclercq, Yann
2016-01-01
Assembly of the cryo-module components in SM18 cleanroom. The superconducting solenoid (housed inside its helium vessel) is cleaned, prepared then installed on the supporting frame of the cryo-module and connected to the helium tank, prior to the assembly of the RF cavities on the structure. The completed first 2 cryo-modules installed inside the HIE-ISOLDE-LINAC ready for beam operation is also shown.
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Results of Cavity Series Fabrication at Jefferson Laboratory for the Cryomodule 'R100'
International Nuclear Information System (INIS)
Marhauser, F.; Clemens, W.A.; Drury, M.A.; Forehand, D.; Henry, J.; Manning, S.; Overton, R.B.; Williams, R.S.
2011-01-01
A series production of eight superconducting RF cavities for the cryomodule R100 was conducted at JLab in 2010. The cavities underwent chemical post-processing prior to vertical high power testing and routinely exceeded the envisaged performance specifications. After cryomodule assembly, cavities were successfully high power acceptance tested. In this paper, we present the achievements paving the way for the first demonstration of 100 MV (and beyond) in a single cryomodule to be operated at CEBAF.
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International Nuclear Information System (INIS)
Campisi, I.E.; Ahlman, R.; Augustine, M.; Crawford, K.; Drury, M.; Jordan, K.; Kelley, P.; Lee, T.; Marshall, J.; Preble, J.; Robb, J.; Schneider, W.; Susta, J.; Van Dyke, J.; Wiseman, M.
1991-01-01
The Continuous Electron Beam Accelerator Facility, (CEBAF) is undergoing construction in Newport News, Virginia. When completed in 1994, the accelerator will be the largest installation of radio frequency superconductivity. Production of cryomodules, the fundamental cryogenic building block of the machine, has started. They consist of four sets of a pair of 1497 MHz, 5-cell cavities contained in separate helium vessels and mounted in a cryostat with appropriate end caps for helium supply and return. In this paper RF, heat load, and mechanical performance of the first unit tested and status of the project is discussed
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MECHANICAL CAVITY DESIGN FOR 100MV UPGRADE CRYOMODULE
International Nuclear Information System (INIS)
K.M. Wilson; G. Ciovati; E. F. Daly; J. Henry; R. Hicks; J. Hogan; D. Machie; P. Kneisel; C. Reece; J. Sekutowicz; T. Whitlatch
2003-01-01
To achieve up to 6 GeV, each cryomodule in the CEBAF accelerator currently provides about 30 MV of acceleration. To raise the accelerator energy to 12 GeV, ten additional cryomodules capable of providing over 100 MV of acceleration are required. A prototype of the 100 MV cryomodule has been designed, is presently under construction, and will be completed in 2004. This prototype cryomodule comprises two new cavity designs, four cavities of the low loss design and four cavities of the high gradient design. Although the cavity shapes were designed for their RF properties, the mechanical implications must be considered. In addition to the new cavity shapes, changes have also been made to the cavity end dish assemblies, weld joints, and stiffening rings. This paper will present the results of the stress and vibration analyses used for designing the cryomodule
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Pattalwar, Shrikant; Jones, Thomas; Strachan, John; Bate, Robert; Davies, Phil; McIntosh, Peter
2012-06-01
Through an international cryomodule collaboration, ASTeC at Daresbury Laboratory has taken the primary responsibility in leading the development of an optimised Superconducting RF (SRF) cryomodule, operating in CW mode for energy recovery facilities and other high duty cycle accelerators. For high beam current operation, Higher Order Mode (HOM) absorbers are critical components of the SRF Cryomodule, ensuring excessive heating of the accelerating structures and beam instabilities are effectively managed. This paper describes some of the cold tests conducted on the HOM absorbers and other critical components during the construction phase, to ensure that the quality and reliable cryomodule performance is maintained.
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Design approach for the development of a cryomodule for compact crab cavities for Hi-Lumi LHC
Pattalwar, Shrikant; Jones, Thomas; Templeton, Niklas; Goudket, Philippe; McIntosh, Peter; Wheelhouse, Alan; Burt, Graeme; Hall, Ben; Wright, Loren; Peterson, Tom
2014-01-01
A prototype Superconducting RF (SRF) cryomodule, comprising multiple compact crab cavities is foreseen to realise a local crab crossing scheme for the "Hi-Lumi LHC", a project launched by CERN to increase the luminosity performance of LHC. A cryomodule with two cavities will be initially installed and tested on the SPS drive accelerator at CERN to evaluate performance with high-intensity proton beams. A series of boundary conditions influence the design of the cryomodule prototype, arising from; the complexity of the cavity design, the requirement for multiple RF couplers, the close proximity to the second LHC beam pipe and the tight space constraints in the SPS and LHC tunnels. As a result, the design of the helium vessel and the cryomodule has become extremely challenging. This paper assesses some of the critical cryogenic and engineering design requirements and describes an optimised cryomodule solution for the evaluation tests on SPS.
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Cryomodule development for the CEBAF upgrade
International Nuclear Information System (INIS)
J. R. Delayen; L. R. Doolittle; E. Feldl; J. Hogan; J. Mammosser; V. Nguyen; H. L. Phillips; J. Preble; W. J. Scheider; D. X. Wang; M. Wiseman
1999-01-01
Long term plans for CEBAF at Jefferson Lab call for achieving 12 GeV in the middle of the next decade and 24 GeV after 2010. In support of these plans, an Upgrade Cryomodule capable of providing more than three times the voltage of the original CEBAF cryomodule specification within the same length is under development. Development activities have been focused on critical areas thought to have maximum impact on the overall design. These have included the cavity structure, rf power coupling, cavity suspension, alignment, cavity tuning, and beamline interface. It has been found that all design and development areas are tightly coupled and can not be developed independently. Substantial progress has been made toward an integrated design for the Jefferson Lab Upgraded Cryomodule
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International Nuclear Information System (INIS)
Sun, Hongyu; Ahmad, Mashkoor; Luo, Jun; Shi, Yingying; Shen, Wanci; Zhu, Jing
2014-01-01
Graphical abstract: The synthesized SnS 2 nanoflakes decorated multiwalled carbon nanotubes hybrid structures exhibit large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS 2 nanoflakes. - Highlights: • Synthesis of SnS 2 nanoflakes decorated multiwalled carbon nanotubes hybrid structures. • Simple solution-phase approach. • Morphology feature of SnS 2 . • Enhanced performance as Li-ion batteries. - Abstract: SnS 2 nanoflakes decorated multiwalled carbon nanotubes (MWCNTs) hybrid structures are directly synthesized via a simple solution-phase approach. The as-prepared SnS 2 /MWCNTs structures are investigated as anode materials for Li-ion batteries as compared with SnS 2 nanoflakes. It has been found that the composite structure exhibit excellent lithium storage performance with a large reversible capacity, superior cycling performance, and good rate capability as compared to pure SnS 2 nanoflakes. The first discharge and charge capacities have been found to be 1416 and 518 mA h g −1 for SnS 2 /MWCNTs composite electrodes at a current density of 100 mA g −1 between 5 mV and 1.15 V versus Li/Li + . A stable reversible capacity of ∼510 mA h g −1 is obtained for 50 cycles. The improved electrochemical performance may be attributed to the flake-morphology feature of SnS 2 and the addition of MWCNTs that can hinder the agglomeration of the active materials and improve the conductivity of the composite electrode simultaneously
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Displacement of cryomodule in CADS injector II
Energy Technology Data Exchange (ETDEWEB)
Yuan, Jiandong; Zhang, Bin; Wang, Fengfeng; Wan, Yuqin; Sun, Guozhen; Yao, Junjie; Zhang, Juihui; He, Yuan [Chinese Academy of Sciences, Lanzhou (China). Inst. of Modern Physics
2017-06-15
As Cryomodule can easily reduce higher power consumption and length of an accelerator and the accelerator can be operated more continuously. The Chinese academy of sciences institute of modern physics is developing an accelerator driven subcritical system (CADS) Injector II. Cryomodules are extremely complex systems, and their design optimization is strongly dependent on the accelerator application for which they are intended.
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Federal Laboratory Consortium — CMTFis able to test complete SRF cryomodules at cryogenic operating temperatures and with RF Power. CMTF will house the PIP-II Injector Experiment allowing test of...
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Growth and photovoltaic performance of SnS quantum dots
Energy Technology Data Exchange (ETDEWEB)
Deepa, K.G., E-mail: deepachaithanya@gmail.com [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore (India); Nagaraju, J. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore (India)
2012-08-01
Highlights: Black-Right-Pointing-Pointer Orthorhombic SnS quantum dots are synthesized by chemical method. Black-Right-Pointing-Pointer HOMO-LUMO level alignments confirmed the electron transport from SnS to TiO{sub 2}. Black-Right-Pointing-Pointer Cell characteristics are analyzed with different size quantum dots. Black-Right-Pointing-Pointer FF increased drastically from 15 to 51% on adding a buffer layer to the structure. Black-Right-Pointing-Pointer The SnS QDSSC showed highest V{sub oc} of 504 mV and 2.3 mA/cm{sup 2}. - Abstract: Tin sulphide (SnS) quantum dots of size ranging from 2.4 to 14.4 nm are prepared by chemical precipitation method in aqueous media. Growth of the SnS particles is monitored by controlling the deposition time. Both XRD and SAED patterns confirm that the particles possess orthorhombic structure. The uncapped SnS particles showed secondary phases like Sn{sub 2}S{sub 3} and SnS{sub 2} which is visible in the SAED pattern. From the electrochemical characterization, HOMO-LUMO levels of both TiO{sub 2} and SnS are determined and the band alignment is found to be favorable for electron transfer from SnS to TiO{sub 2}. Moreover, the HOMO-LUMO levels varied for different particle sizes. Solar cell is fabricated by sensitizing porous TiO{sub 2} thin film with SnS QDs. Cell structure is characterized with and without buffer layer between FTO and TiO{sub 2}. Without the buffer layer, cell showed an open circuit voltage (V{sub oc}) of 504 mV and short circuit current density (J{sub sc}) of 2.3 mA/cm{sup 2} under AM1.5 condition. The low fill factor of this structure (15%) is seen to be increased drastically to 51%, on the incorporation of the buffer layer. The cell characteristics are analyzed using two different size quantum dots.
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Template-free synthesis of novel SnS2 array and its superior performances for lithium ion battery
Zhu, Anquan; Qiao, Lulu; Tan, Pengfei; Ma, Yongjin; Liu, Yi; Pan, Jun
2018-05-01
A kind of novel three-dimensional SnS2 array was fabricated by an ethylenediamine (EDA) assisting low-temperature solvothermal method. It was observed that as-obtained SnS2 array was composed of numerous SnS2 nanosheets with the thickness of about 22 nm. When used as lithium ion batteries (LIBs) anode, the SnS2 array displayed remarkable capacities on rate and cycling performances, delivering the rates with reversible capacities of 763.3, 658.6, 593.6, 554.4 and 450.3 mAh g-1 at the current densities of 0.2, 0.5, 1, 2 and 5 A g-1, respectively. Moreover, the satisfactory cycling performance was also disclosed, remaining capacity of 547.8 mAh g-1 after 100th cycle at 0.2 A g-1, better than some reported pure SnS2 nanostructures. Based on the characterization and experimental results, the reasons of such superior electrochemical performances were determined and elaborated. It means that the SnS2 array possesses promising potential on the renewable energy field.
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Cryogenic System for the Cryomodule Test Stand at Fermilab
Energy Technology Data Exchange (ETDEWEB)
White, Michael J. [Fermilab; Hansen, Benjamin [Fermilab; Klebaner, Arkadiy [Fermilab
2017-10-09
This paper describes the cryogenic system for the Cryomodule Test Stand (CMTS) at the new Cryomodule Test Facility (CMTF) located at Fermilab. CMTS is designed for production testing of the 1.3 GHz and 3.9GHz cryomodules to be used in the Linac Coherent Light Source II (LCLSII), which is an upgrade to an existing accelerator at Stanford Linear Accelerator Laboratory (SLAC). This paper will focus on the cryogenic system that extends from the helium refrigeration plant to the CMTS cave. Topics covered will include component design, installation and commissioning progress, and operational plans. The paper will conclude with a description of the heat load measurement plan.
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LCLS-II CRYOMODULE TRANSPORT SYSTEM TESTING
Energy Technology Data Exchange (ETDEWEB)
Huque, Naeem [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Daly, Edward F. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); McGee, Michael W. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2018-04-01
The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.
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Cryomodule tests of four Tesla-like cavities in the Superconducting RF Test Facility at KEK
Directory of Open Access Journals (Sweden)
Eiji Kako
2010-04-01
Full Text Available A 6-m cryomodule including four Tesla-like cavities was developed, and was tested in the Superconducting RF Test Facility phase-I at KEK. The performance as a total superconducting cavity system was checked in the cryomodule tests at 2 K with high rf power. One of the four cavities achieved a stable pulsed operation at 32 MV/m, which is higher than the operating accelerating gradient in the ILC. The maximum accelerating gradient (E_{acc,max} obtained in the vertical cw tests was maintained or slightly improved in the cryomodule tests operating in a pulse mode. Compensation of the Lorentz force detuning at 31 MV/m was successfully demonstrated by a piezo tuner and predetuning.
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Conceptual Design of the Superconducting Proton Linac Short Cryo-module
Bourcey, N; Capatina, O; Azevedo, P; Montesinos, E; Parma, V; Renaglia, T; Vande Craen, A; Williams, L R; Weingarten, W; Rousselot, S; Duthil, P; Duchesne, P; Reynet, D; Dambre, P
2012-01-01
The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art Superconducting Radio Frequency technology, which would serve as a driver for new physics facilities such as neutrinos and radioactive ion beams. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium b=1 elliptical cavities, operating at 2 K and providing an accelerating field of 25 MV/m, and testing of a string of cavities integrated in a machine-type cryo-module. In an initial phase only four out of the eight cavities of an SPL cryo-module will be tested in a ½ length cryo-module developed for this purpose, and therefore called the Short Cryo-module. This paper presents the conceptual design of the SC, highlighting its innovative principles in terms of cavity supporting and alignment, and describes the integratio...
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SRF Clean Rooms and Cryomodule Assembly
Federal Laboratory Consortium — Three primary cleanroom facilities used for the SRF cryomodule production program are available. All 3 clean rooms have class 10 and class 100 areas. The largest is...
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Engineering and Cryogenic Testing of the ISAC-II Medium Beta Cryomodule
Stanford, G; Laxdal, R E; Rawnsley, B; Ries, T; Sekatchev, I
2004-01-01
The medium beta section of the ISAC-II Heavy Ion Accelerator consists of five cryomodules each containing four quarter wave bulk niobium resonators and one superconducting solenoid. A prototype cryomodule has been designed and assembled at TRIUMF. The cryomodule vacuum space contains a mu-metal shield, an LN2 cooled, copper, thermal shield, plus the cold mass and support system. This paper will describe the design goals, engineering choices and fabrication and assembly techniques as well as report the results of the initial cold tests. In particular we will summarize the alignment procedure and the results from the wire position monitoring system.
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Kim, S.-H.; Afanador, R.; Barnhart, D. L.; Crofford, M.; Degraff, B. D.; Doleans, M.; Galambos, J.; Gold, S. W.; Howell, M. P.; Mammosser, J.; McMahan, C. J.; Neustadt, T. S.; Peters, C.; Saunders, J. W.; Strong, W. H.; Vandygriff, D. J.; Vandygriff, D. M.
2017-04-01
The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenance activities for cryomodules are introduced.
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International Nuclear Information System (INIS)
Kim, Sang-Ho; Afanador, Ralph; Barnhart, Debra L.; Crofford, Mark T.; Degraff, Brian D.
2017-01-01
The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenance activities for cryomodules are introduced.
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Cryomodule tests of the TESLA-like superconducting cavity in KEK-STF
International Nuclear Information System (INIS)
Kako, Eiji; Sato, Masato; Shishido, Toshio; Noguchi, Shuichi; Hatori, Hirofumi; Hayano, Hitoshi; Yamamoto, Yasuchika; Watanabe, Ken
2008-01-01
Construction of STF (Superconducting RF Test Facility) is being carried out at KEK. The STF-Baseline superconducting cavity system, which includes four TESLA-like 9-cell cavities, input couplers and frequency tuners, has been developed for the future ILC project. A 6-m cryomodule including one of four TESLA-like cavities was assembled, and the cryomodule was installed in the tunnel for the initial test, called the STF Phase-0.5. The first cool-down of the cryomodule and high power tests of the cavity had been carried out at 2 K from October to November, 2007. The maximum accelerating gradient (Eacc, max) of 19.3 MV/m was achieved in a specific pulse width of 1.5 msec and a repetition rate of 5 Hz, (23.4 MV/m in a shorter pulse width of 0.6 msec). Compensation of Lorentz force detuning at 18 MV/m was successfully demonstrated by using a piezo tuner. The second cryomodule test for four cavities, called the STF Phase-1.0, is scheduled in July, 2008. (author)
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Datta, T. S.; Kar, S.; Kumar, M.; Choudhury, A.; Chacko, J.; Antony, J.; Babu, S.; Sahu, S. K.
2015-12-01
Five beam line cryomodules with total 27 superconducting Radio Frequency (RF) cavities are installed and commissioned at IUAC to enhance the energy of heavy ion from 15 UD Pelletron. To reduce the heat load at 4.2 K, liquid nitrogen (LN2) cooled intermediate thermal shield is used for all these cryomodules. For three linac cryomodules, concept of forced flow LN2 cooling is used and for superbuncher and rebuncher, thermo-siphon cooling is incorporated. It is noticed that the shield temperature of superbuncher varies from 90 K to 110 K with respect to liquid nitrogen level. The temperature difference can't be explained by using the basic concept of thermo-siphon with the heat load on up flow line. A simple thermo-siphon experimental set up is developed to simulate the thermal shield temperature profile. Mass flow rate of liquid nitrogen is measured with different heat load on up flow line for different liquid levels. It is noticed that small amount of heat load on down flow line have a significant effect on mass flow rate. The present paper will be investigating the data generated from the thermosiphon experimental set up and a theoretical analysis will be presented here to validate the measured temperature profile of the cryomodule shield.
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Commissioning and First Results from the Fermilab Cryomodule Test Stand
Energy Technology Data Exchange (ETDEWEB)
Harms, Elvin; et al.
2017-05-01
A new test stand dedicated to SRF cryomodule testing, CMTS1, has been commissioned and is now in operation at Fermilab. The first device to be cooled down and powered in this facility is the prototype 1.3 GHz cryomodule assembled at Fermilab for LCLS-II. We describe the demonstrated capabilities of CMTS1, report on steps taken during commissioning, provide an overview of first test results, and survey future plans.
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SnS2 nanosheets arrays sandwiched by N-doped carbon and TiO2 for high-performance Na-ion storage
Directory of Open Access Journals (Sweden)
Weina Ren
2018-01-01
Full Text Available In this paper, SnS2 nanosheets arrays sandwiched by porous N-doped carbon and TiO2 (TiO2@SnS2@N-C on flexible carbon cloth are prepared and tested as a free-standing anode for high-performance sodium ion batteries. The as-obtained TiO2@SnS2@N-C composite delivers a remarkable capacity performance (840 mA h g−1 at a current density of 200 mA g−1, excellent rate capability and long-cycling life stability (293 mA h g−1 at 1 A g−1 after 600 cycles. The excellent electrochemical performance can be attributed to the synergistic effect of each component of the unique hybrid structure, in which the SnS2 nanosheets with open framworks offer high capacity, while the porous N-doped carbon nanoplates arrays on flexible carbon cloth are able to improve the conductivity and the TiO2 passivation layer can keep the structure integrity of SnS2 nanosheets.
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Modeling high-Power Accelerators Reliability-SNS LINAC (SNS-ORNL); MAX LINAC (MYRRHA)
International Nuclear Information System (INIS)
Pitigoi, A. E.; Fernandez Ramos, P.
2013-01-01
Improving reliability has recently become a very important objective in the field of particle accelerators. The particle accelerators in operation are constantly undergoing modifications, and improvements are implemented using new technologies, more reliable components or redundant schemes (to obtain more reliability, strength, more power, etc.) A reliability model of SNS (Spallation Neutron Source) LINAC has been developed within MAX project and analysis of the accelerator systems reliability has been performed within the MAX project, using the Risk Spectrum reliability analysis software. The analysis results have been evaluated by comparison with the SNS operational data. Results and conclusions are presented in this paper, oriented to identify design weaknesses and provide recommendations for improving reliability of MYRRHA linear accelerator. The SNS reliability model developed for the MAX preliminary design phase indicates possible avenues for further investigation that could be needed to improve the reliability of the high-power accelerators, in view of the future reliability targets of ADS accelerators.
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International Nuclear Information System (INIS)
Thomas Powers; Davis, G.; Michael Drury; Christiana Grenoble; Hovater, J.; Lawrence King; Tomasz Plawski; Joseph Preble
2005-01-01
Three cryomodules have been designed and built as intermediate prototypes for the CEBAF 12 GeV upgrade. This paper will discuss the commissioning and operational experience with the second of these cryomodules, which was installed and commissioned in the Jefferson Lab 10 kW Free Electron Laser Facility. Within the cryomodule are eight 7-cell, 1497 MHz cavities. It was designed to accelerate 1 mA of beam in excess of 70 MV and to have the same footprint as a standard CEBAF cryomodule. The cryomodule was installed in parallel with the FEL beam line in the spring of 2004 and characterized simultaneous with beam delivery. It was installed in the beam line in the early summer of 2004 and has since been operated as part of an energy recovered linac with 5 mA of beam current and 75 MV accelerating gradient for extended periods of time. Additionally, it was operated at 1 mA of beam current and 80 MV of accelerating gradient for several hours without a trip. In the latter operating mode the beam current was limited by the injector setup
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Fabrication of high crystalline SnS and SnS2 thin films, and their switching device characteristics
Choi, Hyeongsu; Lee, Jeongsu; Shin, Seokyoon; Lee, Juhyun; Lee, Seungjin; Park, Hyunwoo; Kwon, Sejin; Lee, Namgue; Bang, Minwook; Lee, Seung-Beck; Jeon, Hyeongtag
2018-05-01
Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS2) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS2 thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS2 thin film by annealing at 450 °C for 1 h in H2S atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS2 thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 105 and 104 cm‑1 in the visible region, respectively. In addition, SnS and SnS2 thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS2 directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS2 thin films exhibited on–off drain current ratios of 8.8 and 2.1 × 103 and mobilities of 0.21 and 0.014 cm2 V‑1 s‑1, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS2 thin films were 6.0 × 1016 and 8.7 × 1013 cm‑3, respectively, in this experiment.
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Experimental Study of an 805 MHz Cryomodule for the Rare Isotope Accelerator
Grimm, T L; Compton, C; Hartung, W; Johnson, M; Marti, F; Popielarski, J; York, R C
2004-01-01
The Rare Isotope Accelerator (RIA) driver linac will use superconducting, 805 MHz, 6-cell elliptical cavities with geometric β values of 0.47, 0.61 and 0.81. Each elliptical cavity cryomodule will have four cavities [1]. Room temperature sections between each cryomodule will consist of quadrupole doublets, beam instrumentation, and vacuum systems. Michigan State University (MSU) has designed a compact cryostat that reduces the tunnel cross-section and improves the linac real estate gradient. The cold mass alignment is accomplished with a titanium rail system supported by adjustable nitronic links from the top vacuum plate, and is similar to that used for existing MSU magnet designs. The same concept has also been designed to accommodate the quarter-wave and half-wave resonators with superconducting solenoids used at lower velocity in RIA. Construction of a prototype β=0.47 cryomodule was completed in February 2004 and is presently under test in realistic operating conditions. Experimental ...
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Networked Attached Devices at SNS
Blokland, W
2003-01-01
The Spallation Neutron Source (SNS) diagnostic instruments at Oak Ridge National Laboratory are based on the Network Attached Device (NAD) concept. Each pickup or sensor has its own resources such as timing, data acquisition and processing. NADs are individually connected to the network, thus reducing the brittleness inherent in tightly coupled systems. This architecture allows an individual device to fail or to be serviced or removed without disrupting other devices. This paper describes our implementation of the nearly 400 NADs to be deployed. The hardware consists of rack-mounted PCs with standard motherboards and PCI data-acquisition boards. The software environment is based on LabVIEW and EPICS. LabVIEW supports the agile development demanded by modern diagnostic systems. EPICS is the control system standard for the entire SNS facility. To achieve high performance, LabVIEW and EPICS communicate through shared memory. SNS diagnostics are developed by a multi-laboratory partnership including ORNL, BNL, LAN...
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International Nuclear Information System (INIS)
Shea, T.J.; Cameron, P.; Doolittle, L.; Power, J.
2000-01-01
The Spallation Neutron Source (SNS) Project is a collaborative effort to build the next generation neutron science facility at Oak Ridge, TN. The facility will deliver a 2 MW proton beam to a liquid mercury target. Neutrons from this target will be moderated and sent to several state-of-the-art instruments. Six national laboratories are involved in SNS construction. Berkeley (LBNL) will build the front end that produces a 2.5 MeV, 52 mA H-beam. Los Alamos (LANL) is responsible for the 1 GeV linac with a superconducting section provided by Thomas Jefferson (JLab). Brookhaven (BNL) is building the transfer lines and accumulator ring. Oak Ridge (ORNL) and Argonne (ANL) have responsibility for the target and instruments. All activities are coordinated by the SNS project office at Oak Ridge. The high beam power, a desired availability of 95%, and an aggressive commissioning schedule lead to some interesting challenges in beam diagnostics
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Kubo, Shohei; Sakata, Kiriko; Shimizu, Hiroshi
2015-01-01
The adolescent is the big turning point during the life. Adolescents must find positive answer for the question “what is with the quality of oneself” through interactions with neighboring people to develop SELF-IDENTITY. On the other hand, Social Network Services (SNS) are highly familiar to them, making “SNS addiction” become a big social problem. This study attempted causal relationship among self-identity development and using SNS, consequently SNS addiction, from the viewpoint of personal...
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Remote handling equipment for SNS
International Nuclear Information System (INIS)
Poulten, B.H.
1983-01-01
This report gives information on the areas of the SNS, facility which become highly radioactive preventing hands-on maintenance. Levels of activity are sufficiently high in the Target Station Area of the SNS, especially under fault conditions, to warrant reactor technology to be used in the design of the water, drainage and ventilation systems. These problems, together with the type of remote handling equipment required in the SNS, are discussed
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Transverse Matching Progress Of The SNS Superconducting Linac
International Nuclear Information System (INIS)
Zhang, Yan; Cousineau, Sarah M.; Liu, Yun
2011-01-01
Experience using laser-wire beam profile measurement to perform transverse beam matching in the SNS superconducting linac is discussed. As the SNS beam power is ramped up to 1 MW, transverse beam matching becomes a concern to control beam loss and residual activation in the linac. In our experiments, however, beam loss is not very sensitive to the matching condition. In addition, we have encountered difficulties in performing a satisfactory transverse matching with the envelope model currently available in the XAL software framework. Offline data analysis from multi-particle tracking simulation shows that the accuracy of the current online model may not be sufficient for modeling the SC linac.
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Damping the e-p instability in the SNS accumulator ring
Evans, N. J.; Deibele, C.; Aleksandrov, A.; Xie, Z.
2018-03-01
A broadband, digital damper system for both transverse planes developed for the SNS accumulator ring has recently damped the first indications of the broadband 50-150 MHz e-p instability in a 1.2 MW neutron production beam. This paper presents details of the design and operation of the SNS damper system as well as results of active damping of the e-p instability in the SNS ring showing a reduction in power of betatron oscillation over the 10-300 MHz band of up to 70%. The spectral content of the beam during operation, with and without the damper system is presented and performance of the damper system is evaluated.
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Comparison Analysis among Large Amount of SNS Sites
Toriumi, Fujio; Yamamoto, Hitoshi; Suwa, Hirohiko; Okada, Isamu; Izumi, Kiyoshi; Hashimoto, Yasuhiro
In recent years, application of Social Networking Services (SNS) and Blogs are growing as new communication tools on the Internet. Several large-scale SNS sites are prospering; meanwhile, many sites with relatively small scale are offering services. Such small-scale SNSs realize small-group isolated type of communication while neither mixi nor MySpace can do that. However, the studies on SNS are almost about particular large-scale SNSs and cannot analyze whether their results apply for general features or for special characteristics on the SNSs. From the point of view of comparison analysis on SNS, comparison with just several types of those cannot reach a statistically significant level. We analyze many SNS sites with the aim of classifying them by using some approaches. Our paper classifies 50,000 sites for small-scale SNSs and gives their features from the points of network structure, patterns of communication, and growth rate of SNS. The result of analysis for network structure shows that many SNS sites have small-world attribute with short path lengths and high coefficients of their cluster. Distribution of degrees of the SNS sites is close to power law. This result indicates the small-scale SNS sites raise the percentage of users with many friends than mixi. According to the analysis of their coefficients of assortativity, those SNS sites have negative values of assortativity, and that means users with high degree tend to connect users with small degree. Next, we analyze the patterns of user communication. A friend network of SNS is explicit while users' communication behaviors are defined as an implicit network. What kind of relationships do these networks have? To address this question, we obtain some characteristics of users' communication structure and activation patterns of users on the SNS sites. By using new indexes, friend aggregation rate and friend coverage rate, we show that SNS sites with high value of friend coverage rate activate diary postings
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Design and Prototype Progress toward a Superconducting Crab Cavity Cryomodule for the APS
International Nuclear Information System (INIS)
Wang, Haipeng; Cheng, Guangfeng; Ciovati, Gianluigi; Henry, James; Kneisel, Peter; Rimmer, Robert; Slack, Gary; Turlington, Larry; waldschmidt, Geoff; Nassiri, Alireza
2010-01-01
A squashed, elliptical supercondconducting (SC) cavity with waveguide dampers on the beam pipes has currently been chosen as the baseline design for the Short Pulse X-ray (SPX) project at the Advanced Photon Source (APS). An alternate cavity design, with a waveguide damper located directly on the cavity cell for improved damping characteristics, has also been designed and cold-tested with promising results. In either case, eight cavities would be operated CW in a single cryomodule at 2K to produce an electron bunch chirp of 4MV at a frequency of 2.815 GHz. Detailed analysis of multipactoring (MP), Lorentz force detuning (LFD), and the thermal properties of the baseline design has led to an engineering specification of the basic parameters of the cryomodule.
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Conceptual design of cryomodules for RAON
Energy Technology Data Exchange (ETDEWEB)
Kim, Y.; Lee, M. K.; Kim, W. K.; Jang, H. M.; Choi, C. J.; Jo, Y. W.; Kim, H. J.; Jeon, D. [Institute for Basic Science, Daejeon (Korea, Republic of)
2014-09-15
The heavy ion accelerator that will be built in Daejeon, Korea utilizes superconducting cavities operating in 2 K. The cavities are QWR (quarter wave resonator), HWR (half wave resonator), SSR1 (sing spoke resonator1) and SSR2. The main role of the cryomodule is supplying thermal insulation for cryogenic operation of the cavities and maintaining cavities' alignment. Thermal and structural consideration such as thermal load by heat leak and heat generation, cryogenic fluid management, thermal contraction, and so on. This paper describes detailed design considerations and current results have being done including thermal load estimation, cryogenic flow piping, pressure relief system, and so on.
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Huang, Xiaoguang; Woo, Heechul; Wu, Peinian; Hong, Hyo Jin; Jung, Wan Gil; Kim, Bong-Joong; Vanel, Jean-Charles; Choi, Jin Woo
2017-11-28
A simple, low cost, non-toxic and eco-friendly pathway for synthesizing efficient sunlight-driven tin sulfide photocatalyst was studied. SnS nanocrystals were prepared by using mechanical method. The bulk SnS was obtained by evaporation of SnS nanocrystal solution. The synthesized samples were characterized by using XRD, SEM, TEM, UV-vis, and Raman analyses. Well crystallized SnS nanocrystals were verified and the electrochemical characterization was also performed under visible light irradiation. The SnS nanocrystals have shown remarkable photocurrent density of 7.6 mA cm -2 under 100 mW cm -2 which is about 10 times larger than that of the bulk SnS under notably stable operation conditions. Furthermore, the SnS nanocrystals presented higher stability than the bulk form. The IPCE(Incident photon to current conversion efficiency) of 9.3% at 420 nm was obtained for SnS nanocrystal photoanode which is strikingly higher than that of bulk SnS, 0.78%. This work suggests that the enhancement of reacting area by using SnS nanocrystal absorbers could give rise to the improvement of photoelectrochemical cell efficiency.
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The SNS Resonance Control Cooling System Control Valve Upgrade Performance
International Nuclear Information System (INIS)
Williams, Derrick C.; Schubert, James Phillip; Tang, Johnny Y.
2008-01-01
The normal-conducting linac of the Spallation Neutron Source (SNS) uses 10 separate Resonance Control Cooling System (RCCS) water skids to control the resonance of 6 Drift Tube Linac (DTL) and 4 Coupled Cavity Linac (CCL) accelerating structures. The RCCS water skids use 2 control valves; one to regulate the chilled water flow and the other to bypass water to a chilled water heat exchanger. These valves have hydraulic actuators that provide position and feedback to the control system. Frequency oscillations occur using these hydraulic actuators due to their coarse movement and control of the valves. New pneumatic actuator and control positioners have been installed on the DTL3 RCCS water skid to give finer control and regulation of DTL3 cavity temperature. This paper shows a comparison of resonance control performance for the two valve configurations.
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Reliability model of SNS linac (spallation neutron source-ORNL)
International Nuclear Information System (INIS)
Pitigoi, A.; Fernandez, P.
2015-01-01
A reliability model of SNS LINAC (Spallation Neutron Source at Oak Ridge National Laboratory) has been developed using risk spectrum reliability analysis software and the analysis of the accelerator system's reliability has been performed. The analysis results have been evaluated by comparing them with the SNS operational data. This paper presents the main results and conclusions focusing on the definition of design weaknesses and provides recommendations to improve reliability of the MYRRHA ( linear accelerator. The reliability results show that the most affected SNS LINAC parts/systems are: 1) SCL (superconducting linac), front-end systems: IS, LEBT (low-energy beam transport line), MEBT (medium-energy beam transport line), diagnostics and controls; 2) RF systems (especially the SCL RF system); 3) power supplies and PS controllers. These results are in line with the records in the SNS logbook. The reliability issue that needs to be enforced in the linac design is the redundancy of the systems, subsystems and components most affected by failures. For compensation purposes, there is a need for intelligent fail-over redundancy implementation in controllers. Enough diagnostics has to be implemented to allow reliable functioning of the redundant solutions and to ensure the compensation function
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Progress in design of the SNS linac
International Nuclear Information System (INIS)
Hardekopf, R.
2001-01-01
The Spallation Neutron Source (SNS) is a six-laboratory collaboration to build an intense pulsed neutron facility at Oak Ridge, TN. The linac design has evolved from the conceptual design presented in 1997 in order to achieve higher initial performance and to incorporate desirable upgrade features. The linac is now designed to produce 2-MW beam power using a combination of radio-frequency quadrupole (RFQ) linac, drift-tube linac (DTL), coupled-cavity linac (CCL), and superconducting-RF (SRF) linac. Designs of each of these elements support he high peak intensity and high quality beam required for injection into the SNS accumulator ring. This paper will trace the evolution of the linac design and the progress made in the R and D program. (author)
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Assessment of thermal loads in the CERN SPS crab cavities cryomodule1
Carra, F.; Apeland, J.; Calaga, R.; Capatina, O.; Capelli, T.; Verdú-Andrés, S.; Zanoni, C.
2017-07-01
As a part of the HL-LHC upgrade, a cryomodule is designed to host two crab cavities for a first test with protons in the SPS machine. The evaluation of the cryomodule heat loads is essential to dimension the cryogenic infrastructure of the system. The current design features two cryogenic circuits. The first circuit adopts superfluid helium at 2 K to maintain the cavities in the superconducting state. The second circuit, based on helium gas at a temperature between 50 K and 70 K, is connected to the thermal screen, also serving as heat intercept for all the interfaces between the cold mass and the external environment. An overview of the heat loads to both circuits, and the combined numerical and analytical estimations, is presented. The heat load of each element is detailed for the static and dynamic scenarios, with considerations on the design choices for the thermal optimization of the most critical components.
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Effect of indium and antimony doping in SnS single crystals
Energy Technology Data Exchange (ETDEWEB)
Chaki, Sunil H., E-mail: sunilchaki@yahoo.co.in; Chaudhary, Mahesh D.; Deshpande, M.P.
2015-03-15
Highlights: • Single crystals growth of pure SnS, indium doped SnS and antimony doped SnS by direct vapour transport (DVT) technique. • Doping of In and Sb occurred in SnS single crystals by cation replacement. • The replacement mechanism ascertained by EDAX, XRD and substantiated by Raman spectra analysis. • Dopants concentration affects the optical energy bandgap. • Doping influences electrical transport properties. - Abstract: Single crystals of pure SnS, indium (In) doped SnS and antimony (Sb) doped SnS were grown by direct vapour transport (DVT) technique. Two doping concentrations of 5% and 15% each were employed for both In and Sb dopants. Thus in total five samples were studied viz., pure SnS (S1), 5% In doped SnS (S2), 15% In doped SnS (S3), 5% Sb doped SnS (S4) and 15% Sb doped SnS (S5). The grown single crystal samples were characterized by evaluating their surface microstructure, stoichiometric composition, crystal structure, Raman spectroscopy, optical and electrical transport properties using appropriate techniques. The d.c. electrical resistivity and thermoelectric power variations with temperature showed semiconducting and p-type nature of the as-grown single crystal samples. The room temperature Hall Effect measurements further substantiated the semiconducting and p-type nature of the as-grown single crystal samples. The obtained results are deliberated in detail.
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Lian, Qingwang; Zhou, Gang; Liu, Jiatu; Wu, Chen; Wei, Weifeng; Chen, Libao; Li, Chengchao
2017-10-01
Here, we report a new enhanced extrinsic pseudocapacitve Li-ion storage mechanism via lithiation-induced structural optimization strategy. The flower-like C@SnS and bulk SnS exhibit initial capacity decay and subsequent increase of capacity on cycling. After a long-term lithiation/delithiation process, flower-like C@SnS and bulk SnS exhibit improved rate performance and reversible capacity in comparison with those of initial state. Moreover, a high capacity of 530 mAh g-1 is still remained even after 1550 cycles at a high current density of 5.0 A g-1 for flower-like C@SnS after pre-lithiation of 350 cycles. According to the comprehensive analysis of structural evolution and electrochemical performance, it demonstrates that SnS electrodes experience crystal size reduction and further amorphization on cycling, which enhances the reversibility of conversion reaction for SnS, leading to increasing capacity. On the other hand, surface-dominated extrinsic pseudocapacitive contribution results in enhanced rate performance because electrodes expose a large fraction of Li+ sites on surface or near-surface region with structural optimization on cycling. This study reveals that extrinsic pseudocapacitance of SnS can be stimulated via lithiation-induced structural optimization, which gives rise to high-rate and long-lived performances.
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Future Muon Source Possibilities at the SNS
Energy Technology Data Exchange (ETDEWEB)
Williams, Travis J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); MacDougall, Prof. Gregory J. [Univ. of Illinois, Urbana-Champaign, IL (United States)
2017-06-01
The workshop “Future Muon Source Possibilities at the SNS” was held September 1-2, 2016 at Oak Ridge National Laboratory. The workshop aimed to examine the technical feasibility and scientific need to construct a μSR and/or β-NMR facility at the SNS. During the course of the workshop it became evident that recently developed technology could enable the development of a world leading pulsed muon source at SNS, without impacting the neutron science missions of the SNS. The details are discussed below.
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International Nuclear Information System (INIS)
Miller, T.M.; Pevey, R.E.; Lillie, R.A.; Johnson, J.O.
2000-01-01
A detailed radiation transport analysis of the Spallation Neutron Source (SNS) shutters is important for the construction of the SNS because of its impact on conventional facility design, normal operation of the facility, and maintenance operations. Thus far the analysis of the SNS shutter travel gaps has been completed. This analysis was performed using coupled Monte Carlo and multi-dimensional discrete ordinates calculations
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Growth of highly textured SnS on mica using an SnSe buffer layer
International Nuclear Information System (INIS)
Wang, S.F.; Fong, W.K.; Wang, W.; Surya, C.
2014-01-01
We report the growth of SnS thin films on mica substrates by molecular beam epitaxy. Excellent 2D layered structure and strong (001) texture were observed with a record low rocking curve full width at half maximum of ∼ 0.101° for the SnS(004) diffraction. An interface model is used to investigate the nucleation of SnS on mica which indicates the co-existence of six pairs of lateral growth orientations and is in excellent agreement with the experimental Φ-scan measurements indicating 12 peaks separated by 30° from each other. To control the lateral growth of the SnS epilayers we investigate the utilization of a thin SnSe buffer layer deposited on the mica substrate prior to the growth of the SnS thin film. The excellent lattice match between SnSe and mica enhances the alignment of the nucleation of SnS and suppresses the minor lateral orientations along the mica[110] direction and its orthogonal axis. Detailed low-frequency noise measurement was performed to characterize the trap density in the films and our results clearly demonstrate substantial reduction in the density of the localized states in the SnS epilayer with the use of an SnSe buffer layer. - Highlights: • A record low rocking curve FWHM for deposited SnS on mica • Investigation of the nucleation of SnS on mica using the interface model • Investigation of nucleation mechanism by phi-scan measurement • Grain boundary formation from crystallites of various nucleation orientations • Suppression of nucleation orientations using an SnSe buffer layer
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Intercalation of organic molecules into SnS2 single crystals
International Nuclear Information System (INIS)
Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H.; Kloc, C.
2013-01-01
SnS 2 is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS 2e n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS 2 after intercalation revealed defects and stacking mismatches among the SnS 2 layers caused by the intercalation. UV–Vis absorption studies showed a red shift in the band edge of the SnS 2 material after intercalation. The band edge was 2.2 eV for pristine SnS 2 ; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS 2 single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS 2 after intercalation. Highlights: ► Organic molecules intercalated inhomogenously between covalently bonded SnS 2 layers. ► Ethylenediamine (en) intercalate directly into SnS 2 . ► Phenylenediamine (PPD) and naphthalenediamine (NDA) can be intercalated into SnS 2 secondary. ► In a secondary intercalation the bonds between layers are weakened by direct
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SNS project-wide beam current monitors
International Nuclear Information System (INIS)
Kesselman, M.; Witkover, R.; Doolittle, L.; Power, J.
2000-01-01
A consortium of national laboratories is constructing the Spallation Neutron Source [1] (SNS) to be installed at Oak Ridge National Laboratory. There are signal similarities that exist in the beam diagnostic instrumentation that could permit common designs. This paper will focus on the beam current monitoring requirements, and the methods under consideration to measure beam current in various locations throughout the SNS facility
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A Wire Position Monitor System for the ISAC-II Cryomodule Components Alignment
Rawnsley, B; Dutto, G; Fong, K; Laxdal, R E; Ries, T
2004-01-01
TRIUMF is developing ISAC-II, a superconducting (SC) linac. It will comprise 9 cryomodules with a total of 48 niobium cavities and 12 SC solenoids. They must remain aligned at liquid He temperatures: cavities to ±400 μm and solenoids to ±200 μm after a vertical contraction of ~4 mm. A wire position monitor (WPM) system based on a TESLA design has been developed, built, and tested with a prototype cryomodule. The system is based on the measurement of signals induced in pickups by a 215 MHz signal carried by a wire through the WPMs. The wire is stretched between the warm tank walls parallel to the beam axis providing a position reference. The sensors, one per cavity and two per solenoid, are attached to the cold elements to monitor their motion during pre-alignment, pumping and cool down. A WPM consists of four 50 Ω striplines spaced 90° apart. A GaAs multiplexer scans the WPMs and a Bergoz card converts the RF signals to DC X and Y voltages. National Ins...
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Effects of annealing on evaporated SnS thin films
International Nuclear Information System (INIS)
Samsudi Sakrani; Bakar Ismail
1994-01-01
The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound
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Effects of annealing on evaporated SnS thin films
Energy Technology Data Exchange (ETDEWEB)
Sakrani, Samsudi; Ismail, Bakar [Universiti Teknologi Malaysia, Skudai, Johor Bahru (Malaysia). Dept. of Physics
1994-12-31
The effects of annealing of evaporated tin sulphide thin films (SnS) are described. The films were initially deposited onto glass substrate, followed by annealing in an encapsulated carbon block under the running argon gas at 310 degree Celsius. Short time annealing of the films results in a slight change of the compositions to a mix SnS/SnS sub 2 compound, and the tendency of increasing SnS sub 2 formation was observed on the films annealed for longer periods up to 20 hours. X-ray results showed the transformation of SnS peaks (040) and (080) to predominantly SnS sub 2 peaks - (001), (100), (101), and (110). The associated absorption coefficients measured on the films were found to be greater than 10 sup 5 cm sup -1, with indication of higher photon energy leading to the formation of SnS sub 2 compound.
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Ultrasonic synthesis of In-doped SnS nanoparticles and their physical properties
Jamali-Sheini, Farid; Cheraghizade, Mohsen; Yousefi, Ramin
2018-05-01
Indium (In)-doped Tin (II) Sulfide (SnS) nanoparticles (NPs) were synthesized by an ultra-sonication method and their optical, electrical, dielectric and photocatalytic properties were investigated. XRD patterns of the obtained NPs indicated formation of orthorhombic polycrystalline SnS. Field emission scanning electron microscopy exhibited flower-like NPs with particle sizes below 100 nm for both SnS and In-doped SnS samples. Optical analysis showed a decrease in energy band gap of SnS NPs upon In doping. In addition, electrical results demonstrated p-type nature of the synthesized SnS NPs and enhanced electrical conductivity of the NPs due to increased tin vacancy. Dielectric experiments on SnS NPs suggested an electronic polarizations effect to be responsible for changing dielectric properties of the particles, in terms of frequency. Finally, photocatalytic experiments revealed that high degradation power can be obtained using In-doped SnS NPs.
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IMPACT simulation and the SNS linac beam
International Nuclear Information System (INIS)
Zhang, Y.; Qiang, J.
2008-01-01
Multi-particle tracking simulations for the SNS linac beam dynamics studies are performed with the IMPACT code. Beam measurement results are compared with the computer simulations, including beam longitudinal halo and beam losses in the superconducting linac, transverse beam Courant-Snyder parameters and the longitudinal beam emittance in the linac. In most cases, the simulations show good agreement with the measured results
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Spallation Neutron Source (SNS)
Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...
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International Nuclear Information System (INIS)
Charlton, L.A.; Barnes, J.M.; Gabriel, T.A.; Johnson, J.O.
1997-01-01
The pulsed-neutron source SNS facility will start operation at 1 MW. A later upgrade to 5 MW is planned. The facility consists of a linear accelerator, an accumulator ring, and a target station. The protons from the accumulator ring will be injected into the target station at 1 GeV. The subsequent spallation process will then produce low-energy thermal neutrons that may be used for a wide variety of experiments. In this paper the authors discuss neutronic calculations which address various aspects of the moderate design. The computer codes HETC and MCNP were used for these calculations with the former code performing the high-energy transport. Neutrons which fell in energy to 20 MeV or less were then passed to MCNP for further transport
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International Nuclear Information System (INIS)
Gao, Xiaomin; Huang, Guanbo; Gao, Haihuan; Pan, Cheng; Wang, Huan; Yan, Jing; Liu, Yu; Qiu, Haixia; Ma, Ning; Gao, Jianping
2016-01-01
In this work, Bi_2S_3/SnS_2 heterojunction photocatalysts were prepared by combining a hydrothermal technique and a facile in situ growth method. The nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma spectroscopy, X-ray photoelectron spectroscopy, UV–Vis diffusion reflectance spectroscopy and room-temperature photoluminescence spectra. Their photocatalytic performances were evaluated by degrading methyl orange (MO) in aqueous solution (50 mg/L) under visible light (λ > 420 nm) irradiation. It was found that when the mass percentage of Bi_2S_3 in Bi_2S_3/SnS_2 was 7.95 wt%, the as-prepared Bi_2S_3/SnS_2 nanocomposite showed the best photocatalytic activity for the degradation of MO. The highly improved performance of the Bi_2S_3/SnS_2 nanocomposite was mainly ascribed to the efficient charge separation. - Highlights: • Facile fabrication of novel Bi_2S_3/SnS_2 heterojunction photocatalysts. • High-performance photocatalyst for the degradation of organic pollutants. • Good recyclability of catalyst without photo-corrosion. • The photocatalytic mechanism was proposed.
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Ionic liquid-assisted sonochemical synthesis of SnS nanostructures
Energy Technology Data Exchange (ETDEWEB)
García-Gómez, Nora A.; Parra-Arcieniega, Salomé M. de la; Garza-Tovar, Lorena L.; Torres-González, Luis C.; Sánchez, Eduardo M., E-mail: eduardo.sanchezcv@uanl.edu.mx
2014-03-05
Highlight: • Obtention of SnS nanostructures using novel ionic liquid assisted sonochemical method. • Influence of the (BMImBF{sub 4}) ionic liquid in SnS morphology. • Inhibitory effect in SnS crystallinity by structuring agents in ionic environments. -- Abstract: SnS nanoparticles have been successfully synthesized by the ionic liquid-assisted sonochemical method (ILASM). The starting reagents were anhydrous SnCl{sub 2}, thioacetamide, dissolved in ethanol and ionic liquid (IL)1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF{sub 4}) mixtures. Our experiments showed that IL plays an important role in the morphology of SnS. A 1:1 ethanol:IL mixture was found to yield the more interesting features. The lower concentration of Sn (II) in solution favored the presence of nanoplatelets. An increase in ultrasonic time favored crystalline degree and size as well. Also, the effect of additives as 3-mercaptopropionic acid, diethanolamine, ethylene glycol, and trioctyl phosphine oxide is reported. X-ray diffraction (XRD) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis-DRS) were used to characterize the obtained products.
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Online vrienden bepalen de overtuigingskracht van SNS-campagnes
van Noort, G.; Antheunis, M.; van Reijmersdal, E.
2011-01-01
Marketers more and more design advertising campaigns especially for Social Network Sites (SNS), with the aim that SNS users forward these campaigns to their online network. By means of a survey, this study investigates whether the persuasiveness of such campaigns is determined by the strength of the
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Moderator poison design and burn-up calculations at the SNS
International Nuclear Information System (INIS)
Lu, W.; Ferguson, P.D.; Iverson, E.B.; Gallmeier, F.X.; Popova, I.
2008-01-01
The spallation neutron source (SNS) at Oak Ridge National Laboratory was commissioned in April 2006. At the nominal operating power (1.4 MW), it will have thermal neutron fluxes approximately an order of magnitude greater than any existing pulsed spallation source. It thus brings a serious challenge to the lifetime of the moderator poison sheets. The SNS moderators are integrated with the inner reflector plug (IRP) at a cost of ∼$2 million a piece. A replacement of the inner reflector plug presents a significant drawback to the facility due to the activation and the operation cost. Although there are a lot of factors limiting the lifetime of the inner reflector plug, like radiation damage to the structural material and helium production of beryllium, the bottle-neck is the lifetime of the moderator poison sheets. Increasing the thickness of the poison sheet extends the lifetime but would sacrifice the neutronic performance of the moderators. A compromise is accepted at the current SNS target system which uses thick Gd poison sheets at a projected lifetime of 6 MW-years of operation. The calculations in this paper reveal that Cd may be a better poison material from the perspective of lifetime and neutronic performance. In replacing Gd, the inner reflector plug could reach a lifetime of 8 MW-years with ∼5% higher peak neutron fluxes at almost no loss of energy resolution
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SNS EXTRACTION KICKER POWER SUPPLY PROTOTYPE TEST
International Nuclear Information System (INIS)
MI, J.L.; SANDBERG, J.; SANDERS, R.; SOUKAS, A.; ZHANG, W.
2000-01-01
The SNS (Spallation Neutron Source) accumulator ring Extraction System consists of a Fast kicker and a Lambertson Septum magnet. The proposed design will use 14 kicker magnets powered by an Extraction Kicker Power Supply System. They will eject the high power beam from the SNS accumulator ring into RTBT (Ring to Target Beam Tunnel) through a Lambertson Septum magnet. This paper describes some test results of the SNS Extraction Kicker power supply prototype. The high repetition rate of 60 pulse per second operation is the challenging part of the design. In the prototype testing, a 3 kA damp current of 700ns pulse-width, 200 nS rise time and 60 Hz repetition rate at 32 kV PFN operation voltage has been demonstrated. An Extraction kicker power supply system design diagram is depicted
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TRACKING TESTS FOR THE SNS FAST INJECTION BUMP POWER SUPPLY
International Nuclear Information System (INIS)
ENG, W.; CUTLER, R.; DEWAN, S.
2004-01-01
The tracking requirement of the SNS Fast Injection Bump power supplies is described. In addition to the usual tracking between the load current and the input reference of a power supply, these power supplies must also track between pairs of units under slightly different loads. This paper describes the use of a current-null test to measure tracking performances. For the actual tests, a single dummy magnet load was used to measure the tracking between the first two production units at the manufacturer's facility. Using the Yokogawa WE7000 waveform. PC-based measurement instrument, input and output waveforms are digitized and stored in data files. A program written for this application is then used to extract data from these files to construct, analyze the waveforms and characterize the power supply performance. Results of the measurements of two SNS Fast Injection Bump power supplies will be presented in this paper
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CLEARING OF ELECTRON CLOUD IN SNS
International Nuclear Information System (INIS)
WANG, L.; LEE, Y.Y.; RAPRIA, D.
2004-01-01
In this paper we describe a mechanism using the clearing electrodes to remove the electron cloud in the Spallation Neutron Source (SNS) accumulator ring, where strong multipacting could happen at median clearing fields. A similar phenomenon was reported in an experimental study at Los Alamos laboratory's Proton Synchrotron Ring (PSR). We also investigated the effectiveness of the solenoid's clearing mechanism in the SNS, which differs from the short bunch case, such as in B-factories. The titanium nitride (TiN) coating of the chamber walls was applied to reduce the secondary electron yield (SEY)
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Combined adapter for the upgraded cryomodule of the linear collider
International Nuclear Information System (INIS)
Budagov, Yu.; Shirkov, G.; Sabirov, B.; Dobrushin, L.; Bryzgalin, A.; Pekar, E.; Illarionov, S.; Bedeschi, F.; Basti, A.; Fabbricatore, P.
2015-01-01
As part of work on the ILC Project, research was performed on the development of techniques to simplify and make reliable and cheaper the construction of the cryomodules that are core of the main linac. In the current ILC TDR design both the helium vessel surrounding the niobium RF cavities and the connected pipes which channel the exhaust helium gas are made of expensive titanium, one of the few metals that can be welded to niobium by the electron beam technique. In this paper we describe the construction and performance of transition elements, obtained by explosion welding, that can couple the niobium cavity with a stainless steel helium vessel, thus saving large amounts of titanium. A new design, including a minimal titanium intermediate layer, has been built. Preliminary tests yielded a very strong resistance of the bond to extreme temperature shocks from electron beam welding to exposure to cryogenic temperatures. The developed technology allows a trimetallic billet for manufacturing an adapter to be made such that the niobium-titanium bond is free of intermetallic compounds and the effect of the difference in the linear expansion coefficients of the ensemble components is eliminated.
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Brain anatomy alterations associated with Social Networking Site (SNS) addiction
He, Qinghua; Turel, Ofir; Bechara, Antoine
2017-01-01
This study relies on knowledge regarding the neuroplasticity of dual-system components that govern addiction and excessive behavior and suggests that alterations in the grey matter volumes, i.e., brain morphology, of specific regions of interest are associated with technology-related addictions. Using voxel based morphometry (VBM) applied to structural Magnetic Resonance Imaging (MRI) scans of twenty social network site (SNS) users with varying degrees of SNS addiction, we show that SNS addic...
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Synthesis and characterization of different morphological SnS nanomaterials
International Nuclear Information System (INIS)
Chaki, Sunil H; Chaudhary, Mahesh D; Deshpande, M P
2014-01-01
SnS in three nano forms possessing different morphologies such as particles, whiskers and ribbons were synthesised by chemical route. The morphology variation was brought about in the chemical route synthesis by varying a synthesis parameter such as temperature and influencing the synthesis by use of surfactant. The elemental composition determination by energy dispersive analysis of x-rays (EDAX) showed that all three synthesized SnS nanomaterials were tin deficient. The x-ray diffraction (XRD) study of the three SnS nanomaterials showed that all of them possess orthorhombic structure. The Raman spectra of the three SnS nanomaterials showed that all three samples possess three common distinguishable peaks. In them two peaks lying at 98 ± 1 cm −1 and 224 ± 4 cm −1 are the characteristic A g mode of SnS. The third peak lying at 302 ± 1 cm −1 is associated with secondary Sn 2 S 3 phase. The transmission electron microscopy (TEM) confirmed the respective morphologies. The optical analysis showed that they possess direct as well as indirect optical bandgap. The electrical transport properties study on the pellets prepared from the different nanomaterials of SnS showed them to be semiconducting and p-type in nature. The current–voltage (I–V) plots of the silver (Ag)/SnS nanomaterials pellets for dark and incandescent illumination showed that all configurations showed good ohmic behaviour except Ag/SnS nanoribbons pellet configuration under illumination. All the obtained results are discussed in detail. (paper)
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SNS Low-Level RF Control System Design and Performance
Ma, Hengjie; Crofford, Mark; Doolittle, Lawrence; Kasemir, Kay-Uwe; Piller, Maurice; Ratti, Alessandro
2005-01-01
A full digital Low-Level RF controller has been developed for SNS LINAC. Its design is a good example of a modern digital implementation of the classic control theory. The digital hardware for all the control and DSP functionalities, including the final vector modulation, is implemented on a single high-density FPGA. Two models for the digital hardware have been written in VHDL and Verilog respectively, based on a very low latency control algorithm, and both have been being used for supporting the testing and commissioning the LINAC to the date. During the commissioning, the flexibility and ability for precise controls that only digital design on a larger FPGA can offer has proved to be a necessity for meeting the great challenge of a high-power pulsed SCL.
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Progress with the SNS front-end systems
International Nuclear Information System (INIS)
Keller, R.; Abraham, W.; Ayers, J.J.; Cheng, D.W.; Cull, P.; DiGennaro, R.; Doolittle, L.; Gough, R.A.; Greer, J.B.; Hoff, M.D.; Leung, K.N.; Lewis, S.; Lionberger, C.; MacGill, R.; Minamihara, Y.; Monroy, M.; Oshatz, D.; Pruyn, J.; Ratti, A.; Reijonen, J.; Schenkel, T.; Staples, J.W.; Syversrud, D.; Thomae, R.; Virostek, S.; Yourd, R.
2001-01-01
The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project have been described in detail elsewhere [1]. They comprise an rf-driven H - ion source, electrostatic LEBT, four-vane RFQ, and an elaborate MEBT. These systems are planned to be delivered to the SNS facility in Oak Ridge in June 2002. This paper discusses the latest design features, the status of development work, component fabrication and procurements, and experimental results with the first commissioned beamline elements
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International Nuclear Information System (INIS)
Charles Reece; Edward Daly; Stephen Manning; Robert Manus; Samuel Morgan; Joseph Ozelis; Larry Turlington
2005-01-01
Twelve seven-cell niobium cavities for the CEBAF 12 GeV upgrade prototype cryomodule Renascence have been fabricated at JLab and tested individually. This set includes four of the ''Low Loss'' (LL) design and eight of the ''High Gradient'' (HG) design. The fabrication strategy was an efficient mix of batch job-shop component machining and in-house EBW, chemistry, and final-step machining to meet mechanical tolerances. Process highlights will be presented. The cavities have been tested at 2.07 K, the intended CEBAF operating temperature. Performance exceeded the tentative design requirement of 19.2 MV/m cw with less than 29 W dynamic heat dissipation. These results, as well as the HOM damping performance will be presented
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International Nuclear Information System (INIS)
C. E. Reece; E. F. Daly; S. Manning; R. Manus; S. Morgan; J. P. Ozelis; L. Turlington
2005-01-01
Twelve seven-cell niobium cavities for the CEBAF 12 GeV upgrade prototype cryomodule Renascence have been fabricated at JLab and tested individually. This set includes four of the ''Low Loss'' (LL) design and eight of the ''High Gradient'' (HG) design. The fabrication strategy was an efficient mix of batch job-shop component machining and in-house EBW, chemistry, and final-step machining to meet mechanical tolerances. Process highlights will be presented. The cavities have been tested at 2.07 K, the intended CEBAF operating temperature. Performance exceeded the tentative design requirement of 19.2 MV/m CW with less than 29 W dynamic heat dissipation. These results, as well as the HOM damping performance are presented
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Status of the SNS H- ion source and low-energy beam transport system
International Nuclear Information System (INIS)
Keller, R.; Thomae, R.; Stockli, M.; Welton, R.
2002-01-01
The ion source and Low-Energy Transport (LEBT) system that will provide H - ion beams to the Spallation Neutron Source (SNS) Front End and the accelerator chain have been developed into a mature unit that will satisfy the operational needs through the commissioning and early operating phases of SNS. The ion source was derived from the SSC ion source, and many of its original features have been improved to achieve reliable operation at 6% duty factor, producing beam currents in the 35-mA range and above. The LEBT utilizes purely electrostatic focusing and includes static beam-steering elements and a pre-chopper. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on relevant commissioning results obtained with the SNS RFQ accelerator. Perspectives for further improvements will be outlined in concluding remarks
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Xu, Wangwang; Xie, Zhiqiang; Cui, Xiaodan; Zhao, Kangning; Zhang, Lei; Dietrich, Grant; Dooley, Kerry M; Wang, Ying
2015-10-14
Complex hierarchical structures have received tremendous attention due to their superior properties over their constitute components. In this study, hierarchical graphene-encapsulated hollow SnO2@SnS2 nanostructures are successfully prepared by in situ sulfuration on the backbones of hollow SnO2 spheres via a simple hydrothermal method followed by a solvothermal surface modification. The as-prepared hierarchical SnO2@SnS2@rGO nanocomposite can be used as anode material in lithium ion batteries, exhibiting excellent cyclability with a capacity of 583 mAh/g after 100 electrochemical cycles at a specific current of 200 mA/g. This material shows a very low capacity fading of only 0.273% per cycle from the second to the 100th cycle, lower than the capacity degradation of bare SnO2 hollow spheres (0.830%) and single SnS2 nanosheets (0.393%). Even after being cycled at a range of specific currents varied from 100 mA/g to 2000 mA/g, hierarchical SnO2@SnS2@rGO nanocomposites maintain a reversible capacity of 664 mAh/g, which is much higher than single SnS2 nanosheets (374 mAh/g) and bare SnO2 hollow spheres (177 mAh/g). Such significantly improved electrochemical performance can be attributed to the unique hierarchical hollow structure, which not only effectively alleviates the stress resulting from the lithiation/delithiation process and maintaining structural stability during cycling but also reduces aggregation and facilitates ion transport. This work thus demonstrates the great potential of hierarchical SnO2@SnS2@rGO nanocomposites for applications as a high-performance anode material in next-generation lithium ion battery technology.
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Energy Technology Data Exchange (ETDEWEB)
Li, Z.; Akcelik, V.; Xiao, L.; Lee, L.; Ng, C.; Ko, K.; /SLAC; Wang, H.; Marhauser, F.; Sekutowicz, J.; Reece, C.; Rimmer, R.; /Jefferson Lab
2008-06-27
implemented to avoid such problem in the final upgrade design and manufacture. The goal of this work is to utilize advanced simulation tools to understand the high external Q (Q{sub ext}) problem observed in the Renascence cryomodule. In the past years, SLAC has built a set of state-of-the-art advanced simulation tools based on finite-element unstructured meshes and parallel computation implementations on supercomputers [2, 3]. The codes are capable of simulating large complex RF systems with unprecedented resolution and turnaround time. They have been successfully applied to many existing and future accelerator R&D projects to improve the machine performance and to optimize the designs. These tools are essential to perform accurate full system analyses such as the JLab's SRF cavities. We will use the simulation results and the data from the RF measurements to gain a better understanding of the cavity performance and tolerance issues and provide a solid foundation to do the BBU simulation and prediction for the 12GeV Upgrade project by using JLab's BBU codes. In this report, we will focus on the following two main tasks: (1) Ideal cavity simulation--to evaluate the effectiveness of the damping by the higher-order-mode (HOM) couplers, and search for possible trapped modes in a back-to-back cavity pair (e.g. cavity No.4 & No.5). (2) Abnormal cavity study--to understand the cause of the high Q{sub ext} modes in cavity No.5 using an advanced Shape Determination Tool.
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Energy Technology Data Exchange (ETDEWEB)
Cheng, Li; Li, Dan; Dong, Xiangting; Ma, Qianli; Yu, Wensheng; Wang, Xinlu; Yu, Hui; Wang, Jinxian; Liu, Guixia, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)
2017-11-15
SnO{sub 2} nanofibers were fabricated by calcination of the electrospun PVP/SnCl{sub 4} composite nanofibers. For the first time, SnS nanofibers and SnSe nanofibers were successfully synthesized by double crucible sulfurization and selenidation methods via inheriting the morphology of SnO{sub 2} nanofibers used as precursors, respectively. X-ray diffraction (XRD) analysis shows SnS nanofibers and SnSe nanofibers are respectively pure orthorhombic phase with space group of Pbnm and Cmcm. Scanning electron microscope (SEM) observation indicates that the diameters of SnS nanofibers and SnSe nanofibers are respectively 140.54±12.80 nm and 96.52±14.17 nm under the 95 % confidence level. The photocatalytic activities of samples were studied by using rhodamine B (Rh B) as degradation agent. When SnS or SnSe nanofibers are employed as the photocatalysts, the respective degradation rates of Rh B solution under the ultraviolet light irradiation after 200 min irradiation are 92.55 % and 92.86 %. The photocatalytic mechanism and formation process of SnS and SnSe nanofibers are also provided. More importantly, this preparation technique is of universal significance to prepare other metal chalcogenides nanofibers. (author)
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Electronic and magnetic properties of SnS2 monolayer doped with non-magnetic elements
Xiao, Wen-Zhi; Xiao, Gang; Rong, Qing-Yan; Wang, Ling-Ling
2018-05-01
We performed a systematic study of the electronic structures and magnetic properties of SnS2 monolayer doped with non-magnetic elements in groups IA, IIA and IIIA based on the first-principles methods. The doped systems exhibit half-metallic and metallic natures depending on the doping elements. The formation of magnetic moment is attributable to the cooperative effect of the Hund's rule coupling and hole concentration. The spin polarization can be stabilized and enhanced through confining the delocalized impurity states by biaxial tensile strain in hole-doped SnS2 monolayer. Both the double-exchange and p-p exchange mechanisms are simultaneously responsible for the ferromagnetic ground state in those hole-doped materials. Our results demonstrate that spin polarization can be induced and controlled in SnS2 monolayers by non-magnetic doping and tensile strain.
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Photocurrent Enhancement by a Rapid Thermal Treatment of Nanodisk-Shaped SnS Photocathodes.
Patel, Malkeshkumar; Kumar, Mohit; Kim, Joondong; Kim, Yu Kwon
2017-12-21
Photocathodes made from the earth-abundant, ecofriendly mineral tin monosulfide (SnS) can be promising candidates for p/n-type photoelectrochemical cells because they meet the strict requirements of energy band edges for each individual photoelectrode. Herein we fabricated SnS-based cell that exhibited a prolonged photocurrent for 3 h at -0.3 V vs the reversible hydrogen electrode (RHE) in a 0.1 M HCl electrolyte. An enhancement of the cathodic photocurrent from 2 to 6 mA cm -2 is observed through a rapid thermal treatment. Mott-Schottky analysis of SnS samples revealed an anodic shift of 0.7 V in the flat band potential under light illumination. Incident photon-to-current conversion efficiency (IPCE) analysis indicates that an efficient charge transfer appropriate for solar hydrogen generation occurs at the -0.3 V vs RHE potential. This work shows that SnS is a promising material for photocathode in PEC cells and its performance can be enhanced via simple postannealing.
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Thioglycolic acid (TGA) assisted hydrothermal synthesis of SnS nanorods and nanosheets
International Nuclear Information System (INIS)
Biswas, Subhajit; Kar, Soumitra; Chaudhuri, Subhadra
2007-01-01
Nanorods and nanosheets of tin sulfide (SnS) were synthesized by a novel thioglycolic acid (TGA) assisted hydrothermal process. The as prepared nanostructures were characterized by X-ray diffraction (XRD) study, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD study reveals the formation of well-crystallized orthorhombic structure of SnS. Diameter of the SnS nanorods varied within 30-100 nm. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) patterns identify the single crystalline nature for the SnS nanocrystals. The mechanism for the TGA assisted growth for the nanosheets and nanorods have been discussed
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Characterization and Optical Properties of the Single Crystalline SnS Nanowire Arrays
Directory of Open Access Journals (Sweden)
Yue GH
2009-01-01
Full Text Available Abstract The SnS nanowire arrays have been successfully synthesized by the template-assisted pulsed electrochemical deposition in the porous anodized aluminum oxide template. The investigation results showed that the as-synthesized nanowires are single crystalline structures and they have a highly preferential orientation. The ordered SnS nanowire arrays are uniform with a diameter of 50 nm and a length up to several tens of micrometers. The synthesized SnS nanowires exhibit strong absorption in visible and near-infrared spectral region and the direct energy gapE gof SnS nanowires is 1.59 eV.
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Lithium insertion mechanism in SnS2
International Nuclear Information System (INIS)
Lefebvre-Devos, I.; Olivier-Fourcade, J.; Jumas, J.C.; Lavela, P.
2000-01-01
We study lithium insertion in SnS 2 by means of 119 Sn Moessbauer spectroscopy, x-ray absorption spectroscopy at Sn L I,III , and S K edges, and theoretical electronic structures (calculated in the density-functional theory framework). An insertion mechanism is derived according to the Li amount. It shows the influence of the SnS 2 -layered structure on the Sn reduction, particularly the possibility of an intermediate oxidation state between Sn IV and Sn II , which is not observed during Li insertion in three-dimensional sulfides
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Optoelectronic characterizations of vacuum evaporated Cu 2 SnS 3 ...
African Journals Online (AJOL)
... of non-toxic, cheap earthly abundant, ternary compound of Cu2SnS3 thin film. ... film were investigated by X-Ray Diffraction and Scanning Electron Microscope. ... to determine the electrical properties of the deposited Cu2SnS3 ternary films.
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Synthesis and Raman analysis of SnS nanoparticles synthesized by PVP assisted polyol method
Energy Technology Data Exchange (ETDEWEB)
Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, R.V. Nagar, Kalapet, Puducherry-605014 (India)
2015-06-24
SnS film was prepared by a simple drop casting method after synthesizing SnS nanoparticles by using PVP assisted polyol method. Confocal Raman study was carried out for the as deposited and annealed (150, 300 and 400 °C) films at two different excitation wavelengths 514 and 785 nm. At the excitation wavelength of 514 nm, the Raman modes showed for a mixed phase of SnS and SnS{sub 2} up to 150 °C and then only a pure SnS phase was observed up to 400 °C due to the dissociation of SnS{sub 2} in to SnS by releasing S. The increase in intensity of Raman (A{sub g} and B{sub 3g}) as well as IR (B{sub 3u}) active modes of SnS are observed with increasing annealing temperature at excitation wavelength 785 nm due to the increased crystallinity and inactiveness of SnS{sub 2} modes. X-ray diffraction confirming the formation of a single phase of SnS while the greater homogeneity in both size and shape of SnS nanoparticles were confirmed through surface morphology from SEM.
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The SNS target station preliminary Title I shielding analyses
International Nuclear Information System (INIS)
Johnson, J.O.; Santoro, R.T.; Lillie, R.A.; Barnes, J.M.; McNeilly, G.S.
2000-01-01
The Department of Energy (DOE) has given the Spallation Neutron Source (SNS) project approval to begin Title I design of the proposed facility to be built at Oak Ridge National Laboratory (ORNL). During the conceptual design phase of the SNS project, the target station bulk-biological shield was characterized and the activation of the major targets station components was calculated. Shielding requirements were assessed with respect to weight, space, and dose-rate constraints for operating, shut-down, and accident conditions utilizing the SNS shield design criteria, DOE Order 5480.25, and requirements specified in 10 CFR 835. Since completion of the conceptual design phase, there have been major design changes to the target station as a result of the initial shielding and activation analyses, modifications brought about due to engineering concerns, and feedback from numerous external review committees. These design changes have impacted the results of the conceptual design analyses, and consequently, have required a re-investigation of the new design. Furthermore, the conceptual design shielding analysis did not address many of the details associated with the engineering design of the target station. In this paper, some of the proposed SNS target station preliminary Title I shielding design analyses will be presented. The SNS facility (with emphasis on the target station), shielding design requirements, calculational strategy, and source terms used in the analyses will be described. Preliminary results and conclusions, along with recommendations for additional analyses, will also be presented. (author)
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The Spallation Neutron Source (SNS) conceptual design shielding analysis
International Nuclear Information System (INIS)
Johnson, J.O.; Odano, N.; Lillie, R.A.
1998-03-01
The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented
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Simulations of signal amplification and oscillations using a SNS junction
International Nuclear Information System (INIS)
Luiz, A.M.; Soares, V.; Nicolsky, R.
1998-01-01
A superconducting - normal metal - superconducting junction (SNS junction) may exhibit a low voltage negative differential resistance (LVNDR) effect over part of its current voltage characteristic (CVC). As the LVNDR effect is stable against a bias voltage at this CVC range, it should be possible to combine a SNS junction with conventional electronic circuits to obtain electronic devices such as mixers, amplifiers and oscillators. Making use of this remarkable effect, we show that an amplifier may be feasible by assembling a simple voltage divider made up of a SNS junction in series with a resistor. The amplifier circuit includes an adjustable DC voltage supply (the bias voltage) and an AC signal source with a given voltage. The SNS junction is connected in series with a resistor R. Choosing values of the load resistance R approximately equal to the module of the negative differential resistance (dV/dI), at the bias voltage, we may obtain large gains in this amplifier device. In order to get an oscillator, the SNS junction should be connected to a RLC tank circuit with a bias voltage adjusted in the range of the LVNDR region of its CVC. A power output of the order of one microwatt may be easily obtained. (orig.)
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Effects of Ge- and Sb-doping and annealing on the tunable bandgaps of SnS films
Energy Technology Data Exchange (ETDEWEB)
Hsu, Hsuan-Tai; Chiang, Ming-Hung; Huang, Chen-Hao [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Wen-Tai, E-mail: wtlin@mail.ncku.edu.tw [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Fu, Yaw-Shyan [Department of Greenergy, National University of Tainan, Tainan 700, Taiwan (China); Guo, Tzung-Fang [Department of Photonics, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)
2015-06-01
SnS, Ge- and Sb-doped SnS films with single orthorhombic SnS phase were fabricated via solvothermal routes and subsequent spin-coating, respectively. The substitution solubilities of Ge and Sb in SnS are about 6 and 5 at.%, respectively. The bandgaps of Ge- and Sb-doped SnS films can be tuned in the ranges of 1.25–1.35 and 1.30–1.39 eV, respectively. The possible mechanisms for the tunable bandgaps of Ge- and Sb-doped SnS films are discussed. For the Ge- and Sb-doped SnS films subjected to annealing at 200–350 °C in N{sub 2}, the bandgaps of 200 °C-annealed films remain unchanged, while those of 300 °C- and 350 °C-annealed films decrease with the annealing temperature because of the evaporation of Ge and Sb respectively. - Highlights: • Ge- and Sb-doped SnS films were fabricated via spin-coating. • The solubilities of Ge and Sb in SnS are about 6 and 5 at.%, respectively. • The bandgaps of SnS films can be tuned by Ge and Sb doping respectively. • Annealing above 300 °C reduces the bandgaps of Ge- and Sb-doped SnS films.
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Status of the SNS Linac An Overview
Holtkamp, N
2004-01-01
The Spallation Neutron Source SNS is a second generation pulsed neutron source and under construction at Oak Ridge National Laboratory. The SNS is funded by the U.S. Department of Energy?s Office of Basic energy Sciences and is dedicated to the study of the structure and dynamics of materials by neutron scattering. A collaboration composed of six national laboratories (ANL, BNL, TJNAF, LANL, LBNL, ORNL) is responsible for the design and construction of the various subsystems. With the official start in October 1998, the operation of the facility will begin in 2006 and deliver a 1.0 GeV, 1.4 MW proton beam with a pulse length of approximately 700 nanoseconds on a liquid mercury target. The multi-lab collaboration allowed access to a large variety of expertise in order to enhance the delivered beam power by almost an order of magnitude compared to existing neutron facilities. The SNS linac consists of a combination of room temperature and superconducting structures and will be the first pulsed high power sc lin...
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Neutronic moderator design for the Spallation Neutron Source (SNS)
International Nuclear Information System (INIS)
Charlton, L.A.; Barnes, J.M.; Johnson, J.O.; Gabriel, T.A.
1998-01-01
Neutronics analyses are now in progress to support the initial selection of moderator design parameters for the Spallation Neutron Source (SNS). The results of the initial optimization studies involving moderator poison plate location, moderator position, and premoderator performance for the target system are presented in this paper. Also presented is an initial study of the use of a composite moderator to produce a liquid methane like spectrum
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Grounding of SNS Accelerator Structure
Holik, Paul S
2005-01-01
Description of site general grounding network. RF grounding network enhancement underneath the klystron gallery building. Grounding network of the Ring Systems with ground breaks in the Ring Tunnel. Grounding and Bonding of R&D accelerator equipment. SNS Building lightning protection.
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SNS Diagnostics Timing Integration
Long, Cary D; Murphy, Darryl J; Pogge, James; Purcell, John D; Sundaram, Madhan
2005-01-01
The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based running Windows XP Embedded for its OS and LabVIEW as its programming language. Coordinating timing among the various diagnostics instruments with the generation of the beam pulse is a challenging task that we have chosen to divide into three phases. First, timing was derived from VME based systems. In the second phase, described in this paper, timing pulses are generated by an in house designed PCI timing card installed in ten diagnostics PCs. Using fan-out modules, enough triggers were generated for all instruments. This paper describes how the Timing NAD (Network Attached Device) was rapidly developed using our NAD template, LabVIEW's PCI driver wizard, and LabVIEW Channel Access library. The NAD...
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TiO2-SnS2 nanocomposites: solar-active photocatalytic materials for water treatment.
Kovacic, Marin; Kusic, Hrvoje; Fanetti, Mattia; Stangar, Urska Lavrencic; Valant, Matjaz; Dionysiou, Dionysios D; Bozic, Ana Loncaric
2017-08-01
The study is aimed at evaluating TiO 2 -SnS 2 composites as effective solar-active photocatalysts for water treatment. Two strategies for the preparation of TiO 2 -SnS 2 composites were examined: (i) in-situ chemical synthesis followed by immobilization on glass plates and (ii) binding of two components (TiO 2 and SnS 2 ) within the immobilization step. The as-prepared TiO 2 -SnS 2 composites and their sole components (TiO 2 or SnS 2 ) were inspected for composition, crystallinity, and morphology using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analyses. Diffuse reflectance spectroscopy (DRS) was used to determine band gaps of immobilized TiO 2 -SnS 2 and to establish the changes in comparison to respective sole components. The activity of immobilized TiO 2 -SnS 2 composites was tested for the removal of diclofenac (DCF) in aqueous solution under simulated solar irradiation and compared with that of single component photocatalysts. In situ chemical synthesis yielded materials of high crystallinity, while their morphology and composition strongly depended on synthesis conditions applied. TiO 2 -SnS 2 composites exhibited higher activity toward DCF removal and conversion in comparison to their sole components at acidic pH, while only in situ synthesized TiO 2 -SnS 2 composites showed higher activity at neutral pH.
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Preparation and characterization of Cu2SnS3 thin films by electrodeposition
Patel, Biren; Narasimman, R.; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit
2018-05-01
Cu2SnS3 thin films were electrodeposited on F:SnO2/Glass substrates at room temperature by using aqueous solution. Copper and tin were first electrodeposited from single bath and post annealed in the presence of sulphur atmosphere to obtain the Cu2SnS3 phase. The Cu2SnS3 phase with preferred orientation along the (112) crystal direction grows to greater extent by the post annealing of the film. Raman analysis confirms the monoclinic crystal structure of Cu2SnS3 with principle mode of vibration as A1 (symmetric breathing mode) corresponding to the band at 291 cm-1. It also reveals the benign coexistence of orthorhombic Cu3SnS4 and Cu2SnS7 phases. Optical properties of the film show direct band gap of 1.25 eV with a high absorption coefficient of the order of 104 cm-1 in the visible region. Photo activity of the electrodeposited film was established in two electrode photoelectro-chemical cell, where an open circuit voltage of 91.6 mV and a short circuit current density of 10.6 µA/cm2 were recorded. Fabrication of Cu2SnS3 thin film heterojunction solar cell is underway.
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Overview of Privacy in Social Networking Sites (SNS)
Powale, Pallavi I.; Bhutkar, Ganesh D.
2013-07-01
Social Networking Sites (SNS) have become an integral part of communication and life style of people in today's world. Because of the wide range of services offered by SNSs mostly for free of cost, these sites are attracting the attention of all possible Internet users. Most importantly, users from all age groups have become members of SNSs. Since many of the users are not aware of the data thefts associated with information sharing, they freely share their personal information with SNSs. Therefore, SNSs may be used for investigating users' character and social habits by familiar or even unknown persons and agencies. Such commercial and social scenario, has led to number of privacy and security threats. Though, all major issues in SNSs need to be addressed, by SNS providers, privacy of SNS users is the most crucial. And therefore, in this paper, we have focused our discussion on "privacy in SNSs". We have discussed different ways of Personally Identifiable Information (PII) leakages from SNSs, information revelation to third-party domains without user consent and privacy related threats associated with such information sharing. We expect that this comprehensive overview on privacy in SNSs will definitely help in raising user awareness about sharing data and managing their privacy with SNSs. It will also help SNS providers to rethink about their privacy policies.
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SNS Superconducting RF cavity modeling-iterative learning control
Kwon, S I; Wang, Y M
2002-01-01
The Spallation Neutron Source (SNS) Superconducting RF (SRF) linear accelerator is operated with a pulsed beam. For the SRF control system to track the repetitive electromagnetic field reference trajectory, both feedback and feedforward controllers have been proposed. The feedback controller is utilized to guarantee the closed loop system stability and the feedforward controller is used to improve the tracking performance for the repetitive reference trajectory and to suppress repetitive disturbances. As the iteration number increases, the feedforward controller decreases the tracking error. Numerical simulations demonstrate that inclusion of the feedforward controller significantly improves the control system performance over its performance with just the feedback controller.
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SNS Superconducting RF cavity modeling-iterative learning control
International Nuclear Information System (INIS)
Kwon, S.-I.; Regan, Amy; Wang, Y.-M.
2002-01-01
The Spallation Neutron Source (SNS) Superconducting RF (SRF) linear accelerator is operated with a pulsed beam. For the SRF control system to track the repetitive electromagnetic field reference trajectory, both feedback and feedforward controllers have been proposed. The feedback controller is utilized to guarantee the closed loop system stability and the feedforward controller is used to improve the tracking performance for the repetitive reference trajectory and to suppress repetitive disturbances. As the iteration number increases, the feedforward controller decreases the tracking error. Numerical simulations demonstrate that inclusion of the feedforward controller significantly improves the control system performance over its performance with just the feedback controller
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EPICS V4 Evaluation for SNS Neutron Data
Energy Technology Data Exchange (ETDEWEB)
Kasemir, Kay [ORNL; Pearson, Matthew R [ORNL; Guyotte, Greg S [ORNL
2015-01-01
Version 4 of the Experimental Physics and Industrial Control System (EPICS) toolkit allows defining application-specific structured data types (pvData) and offers a network protocol for their efficient exchange (pvAccess). We evaluated V4 for the transport of neutron events from the detectors of the Spallation Neutron Source (SNS) to data acquisition and experiment monitoring systems. This includes the comparison of possible data structures, performance tests, and experience using V4 in production on a beam line.
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International Nuclear Information System (INIS)
Kafashan, Hosein; Azizieh, Mahdi; Balak, Zohre
2017-01-01
Highlights: • Nanostructured SnS_1_-_xSe_x thin films were prepared by using electrodeposition method. • The XRD patterns obviously showed that the synthesized films were polycrystalline. • The PL spectra of SnS_1_-_xSe_x thin films showed four emission peaks. • The UV–vis spectra shows a variation in the optical band gap energy of SnS_1_-_xSe_x thin films from 1.22 to 1.65 eV. • SnS_1_-_xSe_x thin films would be suitable for use as absorber layers. - Abstract: SnS_1_-_xSe_x nanostructures with different Se-dopant concentrations were deposited on fluorine doped tin oxide (FTO) substrate through cathodic electrodeposition technique. The pH, temperature, applied potential (E), and deposition time remained were 2.1, 60 °C, −1 V, and 30 min, respectively. SnS_1_-_xSe_x nanostructures were characterized using X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), energy dispersive X-ray spectroscopy (EDX), room temperature photoluminescence (PL), and UV–vis spectroscopy. The XRD patterns revealed that the SnS_1_-_xSe_x nanostructures were polycrystalline with orthorhombic structure. FESEM showed various kinds of morphologies in SnS_1_-_xSe_x nanostructures due to Se-doping. PL and UV–vis spectroscopy were used to evaluate the optical properties of SnS_1_-_xSe_x thin films. The PL spectra of SnS_1_-_xSe_x nanostructures displayed four emission peaks, those are a blue, a green, an orange, and a red emission. UV–vis spectra showed that the optical band gap energy (E_g) of SnS_1_-_xSe_x nanostructures varied between 1.22–1.65 eV, due to Se-doping.
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Physical properties of very thin SnS films deposited by thermal evaporation
International Nuclear Information System (INIS)
Cheng Shuying; Conibeer, Gavin
2011-01-01
SnS films with thicknesses of 20–65 nm have been deposited on glass substrates by thermal evaporation. The physical properties of the films were investigated using X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultraviolet–visible-near infrared spectroscopy at room temperature. The results from XRD, XPS and Raman spectroscopy analyses indicate that the deposited films mainly exhibit SnS phase, but they may contain a tiny amount of Sn 2 S 3 . The deposited SnS films are pinhole free, smooth and strongly adherent to the surfaces of the substrates. The color of the SnS films changes from pale yellow to brown with the increase of the film thickness from 20 nm to 65 nm. The very smooth surfaces of the thin films result in their high reflectance. The direct bandgap of the films is between 2.15 eV and 2.28 eV which is much larger than 1.3 eV of bulk SnS, this is deserving to be investigated further.
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Spallation Neutron Source SNS Diamond Stripper Foil Development
International Nuclear Information System (INIS)
Shaw, Robert W.; Plum, Michael A.; Wilson, Leslie L.; Feigerle, Charles S.; Borden, Michael J.; Irie, Y.; Sugai, I.; Takagi, A.
2007-01-01
Diamond stripping foils are under development for the SNS. Freestanding, flat 300 to 500 (micro)g/cm 2 foils as large as 17 x 25 mm 2 have been prepared. These nano-textured polycrystalline foils are grown by microwave plasma-assisted chemical vapor deposition in a corrugated format to maintain their flatness. They are mechanically supported on a single edge by a residual portion of their silicon growth substrate; fine foil supporting wires are not required for diamond foils. Six foils were mounted on the SNS foil changer in early 2006 and have performed well in commissioning experiments at reduced operating power. A diamond foil was used during a recent experiment where 15 (micro)C of protons, approximately 64% of the design value, were stored in the ring. A few diamond foils have been tested at LANSCE/PSR, where one foil was in service for a period of five months (820 C of integrated injected charge) before it was replaced. Diamond foils have also been tested in Japan at KEK (640 keV H - ) where their lifetimes slightly surpassed those of evaporated carbon foils, but fell short of those for Sugai's new hybrid boron carbon (HBC) foils.
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Li, Xiang; Liu, Jiangwen; Ouyang, Liuzhang; Yuan, Bin; Yang, Lichun; Zhu, Min
2018-04-01
Carbon coated SnS microplates (SnS@C MPs) were prepared via a facile chemical vapor deposition method using SnS2 nanoflakes as precursor and ethanol vapor as carbon source. The carbon coating restrains the growth of SnS during the heat treatment. Furthermore, it improves the electronic conductivity as well as accommodates volume variations of SnS during the sodiation and desodiation processes. Therefore, the rate capability and cycle performance of the SnS@C MPs as anode materials for sodium-ion batteries are remarkably enhanced compared with the bare SnS and the SnS2 precursor. At current densities of 0.1, 0.2, 0.5, 1 and 2 A g-1, the optimized SnS@C MPs exhibit stable capacities of 602.9, 532.1, 512.2, 465.9 and 427.2 mAh g-1, respectively. At 1 A g-1, they show a reversible capacity of 528.8 mAh g-1 in the first cycle, and maintain 444.7 mAh g-1 after 50 cycles, with capacity retention of 84.1%. The carbon coating through chemical vapor deposition using ethanol vapor as carbon sources is green, simple and cost-effective, which shows great promise to improve the reversible Na+ storage of electrode materials.
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Energy Technology Data Exchange (ETDEWEB)
Huang, Po-Chia [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Huang, Jow-Lay [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung 81148, Taiwan, ROC (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan, ROC (China); Wang, Sheng-Chang; Shaikh, Muhammad Omar [Department of Mechanical Engineering, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan, ROC (China); Lin, Chia-Yu [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)
2015-12-01
SnS of orthorhombic (OR) and metastable (SnS) phases were synthesized by using a simple and facile colloidal method. The tin precursor was synthesized using tin oxide (SnO) and oleic acid (OA), while the sulfur precursor was prepared using sulfur powder (S) and oleyamine (OLA). The sulfur precursor was injected into the tin precursor and the prepared SnS nanocrystals were precipitated at a final reaction temperature of 180 °C. The results show that hexamethyldisilazane (HMDS) can be successfully used as a surfactant to synthesize monodisperse 20 nm metastable SnS nanoparticles, while OR phase SnS nanosheets were obtained without HMDS. The direct bandgap observed for the metastable SnS phase is higher (1.66 eV) as compared to the OR phase (1.46 eV). The large blueshift in the direct bandgap of metastable SnS is caused by the difference in crystal structure. The blueshift in the direct band gap value for OR-SnS could be explained by quantum confinement in two dimensions in the very thin nanosheets. SnS thin films used as a photo anode in a photoelectrochemical (PEC) cell were prepared by spin coating on the fluorine-doped tin oxide (FTO) substrates. The photocurrent density of the SnS (metastable SnS)/FTO and SnS (OR)/FTO are 191.8 μA/cm{sup 2} and 57.61 μA/cm{sup 2} at an applied voltage of − 1 V at 150 W, respectively. These narrow band gap and low cost nanocrystals can be used for applications in future optoelectronic devices. - Highlights: • A facile method to synthesize two different phases of SnS having different morphological and optical properties. • The phases and morphologies of SnS nanocrystal can be controlled by adding capping surfactant hexamethyldisilazane (HMDS). • As we know, this is the first metastable SnS photoanode for application in a photoelectrochemical cell.
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First neutron results from SNS
International Nuclear Information System (INIS)
Leadbetter, A.J.; Abbley, D.; Bailey, I.F.
1985-05-01
The report summarises the analyses of the first neutron results on the pulsed spallation source SNS. The source parameters; aspects of the instrumentation; and experimental results particular to a given beamline; are all discussed. General conclusions based on these data, the detectors and the computing system, are also examined. (U.K.)
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Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light.
Shown, Indrajit; Samireddi, Satyanarayana; Chang, Yu-Chung; Putikam, Raghunath; Chang, Po-Han; Sabbah, Amr; Fu, Fang-Yu; Chen, Wei-Fu; Wu, Chih-I; Yu, Tsyr-Yan; Chung, Po-Wen; Lin, M C; Chen, Li-Chyong; Chen, Kuei-Hsien
2018-01-12
Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS 2 (SnS 2 -C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO 2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS 2 lattice, resulting in different photophysical properties as compared with undoped SnS 2 . This SnS 2 -C photocatalyst significantly enhances the CO 2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS 2 -C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO 2 reduction under visible light, where the in situ carbon-doped SnS 2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.
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Progress on the SNS target station
International Nuclear Information System (INIS)
Carne, A.
1983-01-01
This review gives progress and modifications covering the last eighteen months, under the five broad areas of target, target assembly, control system, bulk shield and remote handling. Finally a discussion of additional facilities to the SNS is presented
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Kafashan, Hosein; Azizieh, Mahdi; Balak, Zohre
2017-07-01
SnS1-xSex nanostructures with different Se-dopant concentrations were deposited on fluorine doped tin oxide (FTO) substrate through cathodic electrodeposition technique. The pH, temperature, applied potential (E), and deposition time remained were 2.1, 60 °C, -1 V, and 30 min, respectively. SnS1-xSex nanostructures were characterized using X-ray diffraction (XRD), field emission scanning electron microcopy (FESEM), energy dispersive X-ray spectroscopy (EDX), room temperature photoluminescence (PL), and UV-vis spectroscopy. The XRD patterns revealed that the SnS1-xSex nanostructures were polycrystalline with orthorhombic structure. FESEM showed various kinds of morphologies in SnS1-xSex nanostructures due to Se-doping. PL and UV-vis spectroscopy were used to evaluate the optical properties of SnS1-xSex thin films. The PL spectra of SnS1-xSex nanostructures displayed four emission peaks, those are a blue, a green, an orange, and a red emission. UV-vis spectra showed that the optical band gap energy (Eg) of SnS1-xSex nanostructures varied between 1.22-1.65 eV, due to Se-doping.
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Development and Testing of a Prototype Tuner for the CEBAF Upgrade Cryomodule
International Nuclear Information System (INIS)
G. Davis; J. Delayen; M. Drury; E. Feldl
2001-01-01
An upgrade cryomodule is being developed for CEBAF at Jefferson Lab. The high-gradient, low-current operation of the superconducting cavities puts stringent requirements on the accuracy of the frequency tuner: a resolution of 1 Hz over a range of 400 KHz. We have developed and tested such a tuner; it consists of a stepper-motor-driven coarse tuner, operating in parallel with a piezo-actuator-driven fine tuner. Tuner test procedures and results are summarized, including frequency resolution, range, and linearity (i.e. frequency vs. tuner position), as well as microphonic effects resulting from tuner operation
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International Nuclear Information System (INIS)
Xu, Ting; Casagrande, Fabio; Ganni, Venkatarao; Knudsen, Peter N.; Strong, William Herb
2011-01-01
Spallation Neutron Source (SNS) at Oak Ridge National Lab (ORNL) is building an independent cryogenic system for its Superconducting Radiofrequency Test Facility (SRFTF). The scope of the system is to support the SNS cryomodule test and cavity test at 2-K (using vacuum pump) and 4.5K for the maintenance purpose and Power Upgrade Project of SNS, and to provide the part of the cooling power needed to backup the current CHL to keep Linac at 4.5-K during CHL maintenance period in the future. The system is constructed in multiple phases. The first phase is to construct an independent 4K helium refrigeration system with helium Dewar and distribution box as load interface. It is schedule to be commissioned in 2013. Here we report the concept design of the system and the status of the first phase of this project.
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Cold Test Results of the ISAC-II Medium Beta High Gradient Cryomodule
Laxdal, R E; Clark, G S; Fong, K; Mitra, A K; Poirier, R L; Rawnsley, B; Ries, T; Sekatchev, I; Stanford, G; Zvyagintsev, V
2004-01-01
Many proposals (RIA, Eurisol, ISAC-II) are emerging for a new generation of high gradient heavy ion accelerators. The ISAC-II medium beta cryomodule represents the first realized application that encorporates many new techniques to improve the performance over machines presently being used for beam delivery. The machine lattice, compatible with multi-charge acceleration, uses high field (9T) superconducting solenoids with bucking coils for active fringe field compensation. The bulk niobium quarter wave medium beta cavity produces 6 MV/m over an effective length of 18cm with a peak surface field of ~30 MV/m. TRIUMF has developed a mechanical tuner capable of both coarse (kHz) and fine (Hz) frequency adjustments of the cavity. The demonstrated tuner resolution is better than 0.1 μm (0.6 Hz). A new rf coupling loop has been developed that operates at 200 Watts forward power with less than 0.5 Watt of power being added to the helium load. Cold alignment in ISAC-II has been done with rf pick-ups using a ...
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Fabrication and optical properties of SnS thin films by SILAR method
International Nuclear Information System (INIS)
Ghosh, Biswajit; Das, Madhumita; Banerjee, Pushan; Das, Subrata
2008-01-01
Although the fabrication of tin disulfide thin films by SILAR method is quiet common, there is, however, no report is available on the growth of SnS thin film using above technique. In the present work, SnS films of 0.20 μm thickness were grown on glass and ITO substrates by SILAR method using SnSO 4 and Na 2 S solution. The as-grown films were smooth and strongly adherent to the substrate. XRD confirmed the deposition of SnS thin films. Scanning electron micrograph revealed almost equal distribution of the particle size well covered on the surface of the substrate. EDAX showed that as-grown SnS films were slightly rich in tin component while UV-vis transmission spectra exhibited high absorption in the visible region. The intense and sharp emission peaks at 680 and 825 nm (near band edge emission) dominated the photoluminescence spectra
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Transverse beam stability measurement and analysis for the SNS accumulator ring
Energy Technology Data Exchange (ETDEWEB)
Xie, Zaipeng [University of Wisconsin-Madison, Madison, WI 53706-1691 (United States); Deibele, Craig, E-mail: deibele@ornl.gov [Oak Ridge National Laboratory, PO BOX 2008 MS6483, Oak Ridge, TN 37831-6461 (United States); Schulte, Michael J.; Hu, Yu-Hen [University of Wisconsin-Madison, Madison, WI 53706-1691 (United States)
2015-07-11
A field-programmable gate array (FPGA)-based transverse feedback damper system was implemented in the Spallation Neutron Source (SNS) accumulator ring with the intention to stabilize the electron–proton (e–p) instability in the frequency range of 1–300 MHz. The transverse feedback damper could also be used as a diagnostic tool by measuring the beam transfer function (BTF). An analysis of the BTF measurements provides the stability diagram for the production beam at SNS. This paper describes the feedback damper system and its setup as the BTF diagnostic tool. Experimental BTF results are presented and beam stability is analyzed by use of the BTF measurements for the SNS accumulator ring.
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Transverse beam stability measurement and analysis for the SNS accumulator ring
International Nuclear Information System (INIS)
Xie, Zaipeng; Deibele, Craig; Schulte, Michael J.; Hu, Yu-Hen
2015-01-01
A field-programmable gate array (FPGA)-based transverse feedback damper system was implemented in the Spallation Neutron Source (SNS) accumulator ring with the intention to stabilize the electron–proton (e–p) instability in the frequency range of 1–300 MHz. The transverse feedback damper could also be used as a diagnostic tool by measuring the beam transfer function (BTF). An analysis of the BTF measurements provides the stability diagram for the production beam at SNS. This paper describes the feedback damper system and its setup as the BTF diagnostic tool. Experimental BTF results are presented and beam stability is analyzed by use of the BTF measurements for the SNS accumulator ring
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Kautzmann, Guillaume; Klumb, Francis; CERN. Geneva. ATS Department
2016-01-01
The new superconducting HIE-ISOLDE Linac replaced most of pre-existing REX ISOLDE facility at CERN. This upgrade involves the design, construction, installation and commissioning of 4 high-β cryomodules. Each high-β cryomodule houses five superconducting cavities and one superconducting solenoid. Beam-physics simulations show that the optimum linac working conditions are obtained when the main axes of the active components, located inside the cryostats, are aligned and permanently monitored on the REX Nominal Beam Line (NBL) within a precision of 0.3 mm for the cavities and 0.15 mm for the solenoids at one sigma level along directions perpendicular to the beam axis. The Monitoring and Alignment Tracking for HIE-ISOLDE (MATHILDE) system has been developed to fulfil the alignment and monitoring needs for components exposed to non-standard environmental conditions such as high vacuum or cryogenic temperatures. MATHILDE is based on opto-electronic sensors (HBCAM) observing, through high quality viewports, spher...
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Effect of thickness on optical properties of thermally evaporated SnS films
International Nuclear Information System (INIS)
Selim, M.S.; Gouda, M.E.; El-Shaarawy, M.G.; Salem, A.M.; Abd El-Ghany, W.A.
2013-01-01
The effect of film thickness on the structure and optical properties of thermally evaporated SnS film has been studied. SnS films with different thicknesses in the range 152–585 nm were deposited onto clean glass substrates at room temperature. X-ray diffraction study revealed that SnS films of thickness ≥ 283 nm are crystalline, whereas films of lower thickness exhibit poor crystalline with more amorphous background. The crystalline nature of the lower film thickness has been confirmed using transmission electron microscope and the corresponding electron diffraction pattern. The thicker film samples showed nearly stoichiometric chemical composition; however, thinner samples are deficient in S and rich in Sn. The optical property of the deposited films has been investigated in the wavelength range 350–2500 nm. The refractive index increases notably with increasing film thickness. The refractive index for the investigated film thicknesses are adequately described by the effective-single-oscillator model. The static refractive index and the static dielectric constant have been calculated. Analysis of the optical absorption coefficient revealed the presence of direct optical transition and the corresponding band gap values were found to decrease as the film thickness increases. - Highlights: ► X-ray diffraction was used to study the structure of SnS films. ► Transmission electron microscope confirms the crystalline state of SnS films. ► The refractive index increases notably with increasing the film thickness. ► The optical band gap of SnS films decreases with increasing film thickness
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Length dependent properties of SNS microbridges
International Nuclear Information System (INIS)
Sauvageau, J.E.; Jain, R.K.; Li, K.; Lukens, J.E.; Ono, R.H.
1985-01-01
Using an in-situ, self-aligned deposition scheme, arrays of variable length SNS junctions in the range of 0.05 μm to 1 μm have been fabricated. Arrays of SNS microbridges of lead-copper and niobium-copper fabricated using this technique have been used to study the length dependence, at constant temperature, of the critical current I and bridge resistance R /SUB d/ . For bridges with lengths pounds greater than the normal metal coherence length xi /SUB n/ (T), the dependence of I /SUB c/ on L is consistent with an exponential dependence on the reduced length l=L/xi /SUB n/ (T). For shorter bridges, deviations from this behavior is seen. It was also found that the bridge resistance R /SUB d/ does not vary linearly with the geometric bridge length but appears to approach a finite value as L→O
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An RF input coupler system for the CEBAF energy upgrade cryomodule
International Nuclear Information System (INIS)
J.R. Delayen; L.R. Doolittle; T. Hiatt; J. Hogan; J. Mammosser; L. Phillips; J. Preble; W.J. Schneider; G. Wu
1999-01-01
Long term plans for CEBAF at Jefferson Lab call for achieving 12 GeV in the middle of the next decade and 24 GeV after 2010. Thus an upgraded cryomodule to more than double the present voltage is under development. A new waveguide coupler system has been designed and prototypes are currently being developed. This coupler, unlike the original, has a nominal Q ext of 2.1 x 10 7 , reduced sensitivity of Q ext to mechanical deformation, reduced field asymmetry within the beam envelope, freedom from window arcing with a single window at 300 K, and is capable of transmitting 6kW CW both traveling wave and in full reflection
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High Intensity Effects in the SNS Accumulator Ring
International Nuclear Information System (INIS)
Holmes, Jeffrey A.; Cousineau, Sarah M.; Danilov, Viatcheslav; Plum, Michael A.; Shishlo, Andrei P.
2008-01-01
Currently operating at 0.5 MW beam power on target, the Spallation Neutron Source (SNS) is already the world's most powerful pulsed neutron source. However, we are only one third of the way to full power. As we ramp toward full power, the control of the beam and beam loss in the ring will be critical. In addition to practical considerations, such as choice of operating point, painting scheme, RF bunching, and beam scattering, it may be necessary to understand and mitigate collective effects due to space charge, impedances, and electron clouds. At each stage of the power ramp-up, we use all available resources to understand and to minimize beam losses. From the standpoint of beam dynamics, the losses observed so far under normal operating conditions have not involved collective phenomena. We are now entering the intensity regime in which this may change. In dedicated high intensity beam studies, we have already observed resistive wall, extraction kicker impedance-driven, and electron cloud activities. The analysis and simulation of this data are important ongoing activities at SNS. This paper discusses the status of this work, as well as other considerations necessary to the successful full power operation of SNS.
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Whittles, TJ; Burton, LA; Skelton, JM; Walsh, A; Veal, TD; Dhanak, VR
2016-01-01
Tin sulfide solar cells show relatively poor efficiencies despite attractive photovoltaic properties, and there is difficulty in identifying separate phases, which are also known to form during Cu2ZnSnS4 depositions. We present X-ray photoemission spectroscopy (XPS) and inverse photoemission spectroscopy measurements of single crystal SnS, SnS2, and Sn2S3, with electronic-structure calculations from density functional theory (DFT). Differences in the XPS spectra of the three phases, including...
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The Research on Informal Learning Model of College Students Based on SNS and Case Study
Lu, Peng; Cong, Xiao; Bi, Fangyan; Zhou, Dongdai
2017-03-01
With the rapid development of network technology, informal learning based on online become the main way for college students to learn a variety of subject knowledge. The favor to the SNS community of students and the characteristics of SNS itself provide a good opportunity for the informal learning of college students. This research first analyzes the related research of the informal learning and SNS, next, discusses the characteristics of informal learning and theoretical basis. Then, it proposed an informal learning model of college students based on SNS according to the support role of SNS to the informal learning of students. Finally, according to the theoretical model and the principles proposed in this study, using the Elgg and related tools which is the open source SNS program to achieve the informal learning community. This research is trying to overcome issues such as the lack of social realism, interactivity, resource transfer mode in the current network informal learning communities, so as to provide a new way of informal learning for college students.
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Yavuz, Arzu Büyükyağci; Carbas, Buket Bezgın; Sönmezoğlu, Savaş; Soylu, Murat
2016-01-01
A new tetrakis 4-(2,5-di-2-thiophen-2-yl-pyrrol-1-yl)-substituted nickel phthalocyanine (NiPc-SNS) has been synthesized. This synthesized NiPc-SNS thin film was deposited on p-type Si substrate using the spin coating method (SCM) to fabricate a NiPc-SNS/ p-Si heterojunction diode. The temperature-dependent electrical characteristics of the NiPc-SNS/ p-Si heterojunction with good rectifying behavior were investigated by current-voltage ( I- V) measurements between 50 K and 300 K. The results indicate that the ideality factor decreases while the barrier height increases with increasing temperature. The barrier inhomogeneity across the NiPc-SNS/ p-Si heterojunction reveals a Gaussian distribution at low temperatures. These results provide further evidence of the more complicated mechanisms occurring in this heterojunction. Based on these findings, NiPc-SNS/ p-Si junction diodes are feasible for use in low-temperature applications.
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The critical current density of an SNS Josephson-junction in high magnetic fields
International Nuclear Information System (INIS)
Carty, George J; Hampshire, Damian P
2013-01-01
Although the functional form of the critical current density (J c ) of superconducting–normal–superconducting (SNS) Josephson-junctions (J-Js) has long been known in the very low field limit (e.g. the sinc function), includes the local properties of the junction and has been confirmed experimentally in many systems, there have been no such general solutions available for high fields. Here, we derive general analytic equations for J c in zero field and in high fields across SNS J-Js for arbitrary resistivity of the superconductor and the normal layer which are consistent with the literature results available in limiting cases. We confirm the validity of the approach using both computational solutions to time-dependent Ginzburg–Landau (TDGL) theory applied to SNS junctions and experimental J c data for an SNS PbBi–Cd–PbBi junction. We suggest that since SNS junctions can be considered the basic building blocks for the description of the grain boundaries of polycrystalline materials because they both provide flux-flow channels, this work may provide a mathematical framework for high J c technological polycrystalline superconductors in high magnetic fields. (paper)
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Synthesis of SnS nanoparticles by SILAR method for quantum dot-sensitized solar cells.
Tsukigase, Hiroki; Suzuki, Yoshikazu; Berger, Marie-Hélène; Sagawa, Takashi; Yoshikawa, Susumu
2011-03-01
SnS-sensitized TiO2 electrodes were applied in quantum dot-sensitized solar cells (QDSSCs) which are environmentally more favorable than conventional Cd or Pb-chalcogenide-sensitized electrodes. SnS nanoparticles were well-distributed over the surface of TiO2 nanoparticles by the successive ionic layer adsorption and reaction (SILAR) method. Deposited SnS nanoparticles had diameter about 3 nm. Under AM1.5 irradiation with 100 mW/cm2 light intensity (at 1 sun), the energy conversion efficiency of obtained cells reached a value of 0.21% (0.25 cm2) at SILAR coating cycles of 5. In addition, the photovoltaic performance was improved by additional ZnS coating on the surface of SnS-sensitized TiO2 electrodes.
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Neutron scattering instruments for the Spallation Neutron Source (SNS)
International Nuclear Information System (INIS)
Crawford, R.K.; Fornek, T.; Herwig, K.W.
1998-01-01
The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments
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ALTERNATIVE MATERIALS FOR RAMP-EDGE SNS JUNCTIONS
International Nuclear Information System (INIS)
Jia, Q.; Fan, Y.; Gim, Y.
1999-01-01
We report on the processing optimization and fabrication of ramp-edge high-temperature superconducting junctions by using alternative materials for both superconductor electrodes and normal-metal barrier. By using Ag-doped YBa 2 Cu 3 O 7-x (Ag:YBCO) as electrodes and a cation-modified compound of (Pr y Gd 0.6-y )Ca 0.4 Ba 1.6 La 0.4 Cu 3 O 7 (y = 0.4, 0.5, and 0.6) as a normal-metal barrier, high-temperature superconducting Josephson junctions have been fabricated in a ramp-edge superconductor/normal-metal/superconductor (SNS) configuration. By using Ag:YBCO as electrodes, we have found that the processing controllability /reproducibility and the stability of the SNS junctions are improved substantially. The junctions fabricated with these alternative materials show well-defined RSJ-like current vs voltage characteristics at liquid nitrogen temperature
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Layered SnS sodium ion battery anodes synthesized near room temperature
Xia, Chuan
2017-08-10
In this report, we demonstrate a simple chemical bath deposition approach for the synthesis of layered SnS nanosheets (typically 6 nm or ~10 layers thick) at very low temperature (40 °C). We successfully synthesized SnS/C hybrid electrodes using a solution-based carbon precursor coating with subsequent carbonization strategy. Our data showed that the ultrathin carbon shell was critical to the cycling stability of the SnS electrodes. As a result, the as-prepared binder-free SnS/C electrodes showed excellent performance as sodium ion battery anodes. Specifically, the SnS/C anodes delivered a reversible capacity as high as 792 mAh·g−1 after 100 cycles at a current density of 100 mA·g−1. They also had superior rate capability (431 mAh·g−1 at 3,000 mA·g−1) and stable long-term cycling performance under a high current density (345 mAh·g−1 after 500 cycles at 3 A·g−1). Our approach opens up a new route to synthesize SnS-based hybrid materials at low temperatures for energy storage and other applications. Our process will be particularly useful for chalcogenide matrix materials that are sensitive to high temperatures during solution synthesis.
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Development of SNS Stream Analysis Based on Forest Disaster Warning Information Service System
Oh, J.; KIM, D.; Kang, M.; Woo, C.; Kim, D.; Seo, J.; Lee, C.; Yoon, H.; Heon, S.
2017-12-01
Forest disasters, such as landslides and wildfires, cause huge economic losses and casualties, and the cost of recovery is increasing every year. While forest disaster mitigation technologies have been focused on the development of prevention and response technologies, they are now required to evolve into evacuation and border evacuation, and to develop technologies fused with ICT. In this study, we analyze the SNS (Social Network Service) stream and implement a system to detect the message that the forest disaster occurred or the forest disaster, and search the keyword related to the forest disaster in advance in real time. It is possible to detect more accurate forest disaster messages by repeatedly learning the retrieved results using machine learning techniques. To do this, we designed and implemented a system based on Hadoop and Spark, a distributed parallel processing platform, to handle Twitter stream messages that open SNS. In order to develop the technology to notify the information of forest disaster risk, a linkage of technology such as CBS (Cell Broadcasting System) based on mobile communication, internet-based civil defense siren, SNS and the legal and institutional issues for applying these technologies are examined. And the protocol of the forest disaster warning information service system that can deliver the SNS analysis result was developed. As a result, it was possible to grasp real-time forest disaster situation by real-time big data analysis of SNS that occurred during forest disasters. In addition, we confirmed that it is possible to rapidly propagate alarm or warning according to the disaster situation by using the function of the forest disaster warning information notification service. However, the limitation of system application due to the restriction of opening and sharing of SNS data currently in service and the disclosure of personal information remains a problem to be solved in the future. Keyword : SNS stream, Big data, Machine
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Directory of Open Access Journals (Sweden)
Jinyoung Min
2017-12-01
Full Text Available As the use of social network sites (SNS has become increasingly prevalent, its effect on sustainable performance has received much attention. The existing literature has taken either a positive or negative view of SNS, arguing that it either decreases performance by taking time and effort away from work, or increases performance by providing social benefits for enhancing performance. In contrast, this experimental study, investigates how SNS use can disturb or enhance the performance of different types of tasks differently, thus influencing the sustainability of task performance. Based on distraction-conflict theory, this study distinguishes between simple and complex tasks, examines the role of SNS, and analyzes data including electroencephalography data captured by a brain-computer interface. The results show that task performance can be sustainable such that SNS use positively influences performance when participants are engaged in a simple task and influences performance neither positively nor negatively when participants are engaged in a complex task. The study finds the former result is attributable to the positive effect of the psychological arousal induced by SNS use and the latter result to the negative effect of the psychological arousal offsetting the positive effect of reduced stress resulting from SNS use.
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International Nuclear Information System (INIS)
Keller, R.; Thomae, R.; Stockli, M.; Welton, R.
2002-01-01
The ion source and Low-Energy Transport (LEBT) system that will provide H - ion beams to the Spallation Neutron Source (SNS)** Front End and the accelerator chain have been developed into a mature unit that fully satisfies the operational requirements through the commissioning and early operating phases of SNS. Compared to the early R and D version, many features of the ion source have been improved, and reliable operation at 6% duty factor has been achieved producing beam currents in the 35-mA range and above. LEBT operation proved that the purely electrostatic focusing principle is well suited to inject the ion beam into the RFQ accelerator, including the steering and pre-chopping functions. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on commissioning results obtained with the SNS RFQ and Medium-Energy Beam Transport (MEBT) system. Prospects for further improvements will be outlined in concluding remarks
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DATA ACQUISITION FOR SNS BEAM LOSS MONITOR SYSTEM
International Nuclear Information System (INIS)
YENG, Y.; GASSNER, D.; HOFF, L.; WITKOVER, R.
2003-01-01
The Spallation Neutron Source (SNS) beam loss monitor system uses VME based electronics to measure the radiation produced by lost beam. Beam loss signals from cylindrical argon-filled ion chambers and neutron detectors will be conditioned in analog front-end (AFE) circuitry. These signals will be digitized and further processed in a dedicated VME crate. Fast beam inhibit and low-level, long-term loss warnings will be generated to provide machine protection. The fast loss data will have a bandwidth of 35kHz. While the low level, long-term loss data will have much higher sensitivity. This is further complicated by the 3 decade range of intensity as the Ring accumulates beam. Therefore a bandwidth of 100kHz and dynamic range larger than 21 bits data acquisition system will be required for this purpose. Based on the evaluation of several commercial ADC modules in preliminary design phase, a 24 bits Sigma-Delta data acquisition VME bus card was chosen as the SNS BLM digitizer. An associated vxworks driver and EPICS device support module also have been developed at BNL. Simulating test results showed this system is fully qualified for both fast loss and low-level, long-term loss application. The first prototype including data acquisition hardware setup and EPICS software (running database and OPI clients) will be used in SNS Drift Tube Linac (DTL) system commissioning
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Fabrication of SnS quantum dots for solar cell applications: issues of capping and doping
Rath, J.K.; Prastani, C.; Nanu, D.E.; Nanu, M.; Schropp, R.E.I.; Vetushka, A.; Hývl, M.; Fejfar, A.
2014-01-01
We present our recent study of SnS particles in the backdrop of significant developments that have taken place so far for which a review of the present status of this material, its structural, optical, electronic characteristics, and device performance is described. To further improve the
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Liu, Enzhou; Chen, Jibing; Ma, Yongning; Feng, Juan; Jia, Jia; Fan, Jun; Hu, Xiaoyun
2018-08-15
In this work, the 2D SnS 2 /g-C 3 N 4 heterojunctions were successfully prepared by heating the homogeneous dispersion of SnS 2 nanosheets and g-C 3 N 4 nanosheets using a microwave muffle. SEM, TEM and HRTEM images indicated that the SnS 2 nanosheets were loaded on the surface of the g-C 3 N 4 nanosheets. The UV-vis spectra show that the absorption intensity of the as-prepared samples was increased and the absorption range was also extended from 420 nm to approximately 600 nm. The H 2 production rate over 5 wt% SnS 2 /g-C 3 N 4 can reach 972.6 μmol·h -1 ·g -1 under visible light irradiation (λ > 420 nm) using TEOA as the sacrifice agent and Pt as the electron trap, which is 2.9 and 25.6 times higher than those of the pristine g-C 3 N 4 and SnS 2 , respectively. According to the obtained PL spectra, photocurrent and EIS spectra, the enhanced performance for H 2 generation over the heterojunctions is primarily ascribed to the rapid charge transfer arising from the suitable band gap positions leading to an improved photocatalytic performance. The recycling experiments indicated that the as-prepared composites exhibit good stability in H 2 production. Additionally, a possible enhanced mechanism for H 2 evolution was deduced based on the results obtained by various characterization techniques. Copyright © 2018 Elsevier Inc. All rights reserved.
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SNS accumulator ring design and space charge considerations
International Nuclear Information System (INIS)
Weng, W.T.
1998-01-01
The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5micros with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with 1 x 10 14 protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec long H - beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generation and beam collimation etc. is discussed
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Comparative study of SnS recrystallization in molten CdI{sub 2}, SnCl{sub 2}and KI
Energy Technology Data Exchange (ETDEWEB)
Timmo, Kristi; Kauk-Kuusik, Marit; Pilvet, Maris; Mikli, Valdek; Kaerber, Erki; Raadik, Taavi; Leinemann, Inga; Altosaar, Mare; Raudoja, Jaan [Department of Materials Science, Tallinn University of Technology, Tallinn (Estonia)
2016-01-15
In the present study, the recrystallization of polycrystalline SnS in different molten salts CdI{sub 2}, SnCl{sub 2} and KI as flux materials are presented. The recrystallization and growth of polycrystalline material in molten salts produces unique SnS monograin powders usable in monograin layer solar cells. XRD and Raman analysis revealed that single phase SnS powder can be obtained in KI at 740 C and in SnCl{sub 2} at 500 C. Long time heating of SnS in molten CdI{sub 2} was accompanied by chemical interaction between SnS and CdI{sub 2} that resulted in a mixture of CdS and Sn{sub 2}S{sub 3} crystals. SEM images showed that morphology of crystals can be controlled by the nature of the flux materials: needle-like Sn{sub 2}S{sub 3} together with round edged crystals of CdS in CdI{sub 2}, flat crystals of SnS with smooth surfaces in SnCl{sub 2} and well-formed SnS crystals with rounded edges in KI had been formed. The temperatures of phase transitions and/or the interactions of SnS and flux materials were determined by differential thermal analysis. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Reactivation and reuse of TiO2-SnS2 composite catalyst for solar-driven water treatment.
Kovacic, Marin; Kopcic, Nina; Kusic, Hrvoje; Stangar, Urska Lavrencic; Dionysiou, Dionysios D; Bozic, Ana Loncaric
2018-01-01
One of the most important features of photocatalytic materials intended to be used for water treatment is their long-term stability. The study is focused on the application of thermal and chemical treatments for the reactivation of TiO 2 -SnS 2 composite photocatalyst, prepared by hydrothermal synthesis and immobilized on the glass support using titania/silica binder. Such a catalytic system was applied in solar-driven treatment, solar/TiO 2 -SnS 2 /H 2 O 2 , for the purification of water contaminated with diclofenac (DCF). The effectiveness of studied reactivation methods for retaining TiO 2 -SnS 2 activity in consecutive cycles was evaluated on basis of DCF removal and conversion, and TOC removal and mineralization of organic content. Besides these water quality parameters, biodegradability changes in DCF aqueous solution treated by solar/TiO 2 -SnS 2 /H 2 O 2 process using simply reused (air-dried) and thermally and chemically reactivated composite photocatalyst through six consecutive cycles were monitored. It was established that both thermal and chemical reactivation retain TiO 2 -SnS 2 activity in the second cycle of its reuse. However, both treatments caused the alteration in the TiO 2 -SnS 2 morphology due to the partial transformation of visible-active SnS 2 into non-active SnO 2 . Such alteration, repeated through consecutive reactivation and reuse, was reflected through gradual activity loss of TiO 2 -SnS 2 composite in applied solar-driven water treatment.
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SNS Sample Activation Calculator Flux Recommendations and Validation
Energy Technology Data Exchange (ETDEWEB)
McClanahan, Tucker C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Gallmeier, Franz X. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Iverson, Erik B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Lu, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
2015-02-01
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) uses the Sample Activation Calculator (SAC) to calculate the activation of a sample after the sample has been exposed to the neutron beam in one of the SNS beamlines. The SAC webpage takes user inputs (choice of beamline, the mass, composition and area of the sample, irradiation time, decay time, etc.) and calculates the activation for the sample. In recent years, the SAC has been incorporated into the user proposal and sample handling process, and instrument teams and users have noticed discrepancies in the predicted activation of their samples. The Neutronics Analysis Team validated SAC by performing measurements on select beamlines and confirmed the discrepancies seen by the instrument teams and users. The conclusions were that the discrepancies were a result of a combination of faulty neutron flux spectra for the instruments, improper inputs supplied by SAC (1.12), and a mishandling of cross section data in the Sample Activation Program for Easy Use (SAPEU) (1.1.2). This report focuses on the conclusion that the SAPEU (1.1.2) beamline neutron flux spectra have errors and are a significant contributor to the activation discrepancies. The results of the analysis of the SAPEU (1.1.2) flux spectra for all beamlines will be discussed in detail. The recommendations for the implementation of improved neutron flux spectra in SAPEU (1.1.3) are also discussed.
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Physical properties of SnS thin films grown by hot wall deposition
International Nuclear Information System (INIS)
Gremenok, V.; Ivanov, V.; Bashkirov, S.; Unuchak, D.; Lazenka, V.; Bente, K.; Tashlykov, I.; Turovets, A.
2010-01-01
Full text : Recently, considerable effort has been invested to gain a better and deeper knowledge of structural and physical properties of metal chalcogenide semiconductors because of their potential application in electrical and photonic devices. Among them, tin sulphide (SnS) has attracted attention because of band gap of 1.3 eV and an absorption coefficient greater than 10 4 cm - 1. Additionally, by using tin sulfide compounds for photovoltaic devices, the production costs are decreased, because these materials are cheap and abundant in nature. For the sythesis of SnS thin films by hot wall deposition, SnS ingots were used as the source materials synthesized from high purity elements (99.999 percent). The thin films were grown onto glass at substrate temperatures between 220 and 380 degrees Celsium. The thickness of the films was in the range of 1.0 - 2.5 μm. The crystal structure and crystalline phases of the materials were studied by XRD using a Siemens D-5000 diffractometer with CuK α (λ = 1.5418 A) radiation. In order to consider instrumental error, the samples were coated by Si powder suspended in acetone. The composition and surface morphology of thin films were investigated by electron probe microanalysis (EPMA) using a CAMECA SX-100, a scanning electron microscope JEOL 6400 and an atomic force microscope (AFM, Model: NT 206), respectively. Depth profiling was performed by Auger electron spectroscopy (AES) using a Perkin Elmer Physical Electronics 590. The electrical resistivity was studied by van der Pauw four-probe technique using silver paste contact. The optical transmittance was carried out using a Varian Cary 50 UV - VIS spectrophotometer in the range 500 - 2000 nm. The as-grown films exhibited a composition with a Sn/S at. percent ratio of 1.06. The AES depth profiles revealed relatively uniform composition through the film thickness. The XRD analysis of the SnS films showed that they were monophase (JCPDS 39-0354), polycrystalline with
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INJECTION CARBON STRIPPING FOIL ISSUES IN THE SNS ACCUMULATOR RING
International Nuclear Information System (INIS)
BEEBE-WANG, J.; LEE, Y.Y.; RAPARIA, D.; WEI, J.
2001-01-01
We are reporting the results of studies on issues related to the injection stripping foil in the Spallation Neutron Source (SNS) accumulator ring. The problems related to foil heating and foil lifetime, such as current density distribution and temperature distribution in the foil, are investigated. The impact of injection errors on the beam losses at the foil is studied. The particle traversal rate and the beam losses due to scattering in the foil are summarized. Finally, SNS end-to-end simulation results of the foil-missing rate, the foil-hitting rate and the maximum foil temperature are presented
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Combinatorial development of Cu2SnS3 as an earth abundant photovoltaic absorber
Baranowski, Lauryn L.
The development of high efficiency, earth abundant photovoltaic absorbers is critical if photovoltaics are to be implemented on the TW scale. Although traditional thin films absorbers such as Cu(In,Ga)Se2 and CdTe have achieved over 20% device efficiencies, the ultimately scalability of these devices may be limited by elemental scarcity and toxicity issues. To date, the most successful earth abundant thin film absorber is Cu2ZnSn(S,Se) 4, which has achieved 12.6% efficiency as of 2014. However, chemical complexity and disorder issues with this material have made the path to higher efficiency CZTSSe devices unclear. As a result, many researchers are now exploring alternative earth abundant absorber materials. In this thesis, we apply our "rapid development" methodology to the exploration of alternative photovoltaic absorbers. The rapid development (RD) methodology, consisting of exploration, research, and development stages, uses complementary theory and experiment to assess candidate materials and down-select in each stage. The overall result is that, in the time span of ~2-3 years, we are able to rapidly go from tens of possible absorber materials to 1-2 working PV device prototypes. Here, we demonstrate the RD approach as applied to the Cu-Sn-S system. We begin our investigation of the Cu-Sn-S system by evaluating the thermodynamic stability, electrical transport, electronic structure, and optical and defect properties of candidate materials using complementary theory and experiment. We find that Cu2SnS3 is the most promising absorber candidate because of its strong optical absorption, tunable doping, and wide stability range. Our other candidate compounds suffer from serious flaws that preclude them from being successful photovoltaic absorbers, including too high experimental conductivity (Cu4SnS4), or poor hole transport and low absorption coefficient (Cu4Sn7S16). Next, we investigate the doping and defect physics of Cu2SnS 3. We identify the origins of the
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THIN DIAMOND FILMS FOR SNS H INJECTIONS STRIPPING
International Nuclear Information System (INIS)
SHAW, R.W.; HERR, A.D.; FEIGERLE, C.S.; CUTLER, R.J.; LIAW, C.J.; LEE, Y.Y.
2004-01-01
We have investigated the preparation and testing of thin diamond foils for use in stripping the SNS H - Linac beam. A long useful lifetime for these foils is desirable to improve operational efficiency. Preliminary data presented at PAC 2001 indicated that diamond foils were superior to conventional evaporated carbon foils, exhibiting lifetimes approximately five-fold longer [1]. That work employed a fully supported diamond foil, a format that is not acceptable for the SNS application; at least two edges of the approximately 1 x 1 cm foils must be free standing to allow for beam rastering. Residual stress in a chemical vapor deposited (CVD) diamond foil results in film distortion (scrolling) when the film is released from its silicon growth substrate. We have attacked this problem by initially patterning the surface of CVD growth substrates with a 50 or 100 line/inch trapezoidal grating, followed by conformal diamond film growth on the patterned substrate. Then removal of the substrate by chemical etching produced a foil that possessed improved mechanical integrity due to its corrugation. The high nucleation density required to grow continuous, pinhole free diamond foils of the desired thickness (1 (micro)m, 350 (micro)g/cm 2 ) was achieved by a combination of substrate surface scratching and seeding. A variety of diamond foils have been tested using the BNL 750 keV Radio Frequency Quadrupole H - beam to simulate energy loss in the SNS. Those include flat, corrugated, microcrystalline, and nanocrystalline foils. Foil lifetimes are reported
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SNS online display technologies for EPICS
International Nuclear Information System (INIS)
Kasemir, K.U.; Chen, X.; Purcell, J.; Danilova, E.
2012-01-01
The ubiquitousness of web clients from personal computers to cell phones results in a growing demand for web-based access to control system data. At the Oak Ridge National Laboratory Spallation Neutron Source (SNS) we have investigated different technical approaches to provide read access to data in the Experimental Physics and Industrial Control System (EPICS) for a wide variety of web client devices. The core web technology, HTTP, is less than ideal for online control system displays. Appropriate use of Ajax, especially the Long Poll paradigm, can alleviate fundamental HTTP limitations. The SNS Status web uses basic Ajax technology to generate generic displays for a wide audience. The Dashboard uses Long Poll and more client-side Java-Script to offer more customization and faster updates for users that need specialized displays. The Web OPI uses RAP for web access to any BOY display, offering utmost flexibility because users can create their own BOY displays in CSS. These three approaches complement each other. Users can access generic status displays with zero effort, invest time in creating their fully customized displays for the Web OPI, or use the Dashboard as an intermediate solution
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Recent Neutronic Optimization Studies at the SNS
International Nuclear Information System (INIS)
Murphy, B.D.; Ferguson, P.D.
2002-01-01
Recent design considerations at the Spallation Neutron Source have led to significant changes in the target station design, including changing the outer lead reflector to stainless steel and adding structural elements to aid heat transfer. In light of the design evolution, basic design decisions, including the moderator positions, were re-evaluated. With the proton beam energy of 1.0 GeV and a beam power of 2 MW, moderator positions were originally selected to optimize the performance of the upstream moderators, although some penalty was accepted in order to enhance the overall performance of the mixed coupled and decoupled moderators in the SNS target system. The work presented in this paper details sensitivity studies of selected moderator positions as a function of neutron energy. A possible change in proton beam energy, to 1.3 GeV while maintaining a beam power of 2 MW, is also studied in terms of moderator position. (authors)
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SNS accumulator ring design and space charge considerations
Energy Technology Data Exchange (ETDEWEB)
Weng, W.T.
1998-08-01
The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5 {micro}s with average beam power of 1 MW. To achieve such purpose, a proton storage ring operated at 60 Hz with 1 {times} 10{sup 14} protons per pulse at 1 GeV is required. The Accumulator Ring (AR) receives 1 msec long H{sup {minus}} beam bunches of 28 mA from a 1 GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1 mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generatino and beam collimation etc. is discussed.
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SNS ACCUMULATOR RING DESIGN AND SPACE CHARGE CONSIDERATIONS
Energy Technology Data Exchange (ETDEWEB)
WENG,W.T.
1998-05-04
The goal of the proposed Spallation Neutron Source (SNS) is to provide a short pulse proton beam of about 0.5{micro}s with average beam power of 1MW. To achieve such purpose, a proton storage ring operated at 60Hz with 1 x 10{sup 14} protons per pulse at 1GeV is required. The Accumulator Ring (AR) receives 1msec long H{sup {minus}} beam bunches of 28mA from a 1GeV linac. Scope and design performance goals of the AR are presented. About 1,200 turns of charge exchange injection is needed to accumulate 1mA in the ring. After a brief description of the lattice design and machine performance parameters, space charge related issues, such as: tune shifts, stopband corrections, halo generation and beam collimation etc. is discussed.
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Deformation Monitoring of the Spallation Neutron Source (SNS) Tunnels
Error, J J; Fazekas, J J; Helus, S A; Maines, J R
2005-01-01
The SNS Project is a 1.4 MW accelerator-based neutron source located at Oak Ridge National Laboratory in Oak Ridge, Tennessee. For shielding purposes, a 17 foot berm of native soil has been constructed on top of the accelerator tunnel system. This backfill has caused ongoing settlement of the tunnels. The settlement has been monitored by the SNS Survey and Alignment Group at regular intervals, in order to discover the patterns of deformation, and to determine when the tunnels will be stable enough for precise alignment of beam line components. The latest monitoring results indicate that the settlement rate has significantly decreased. This paper discusses the techniques and instrumentation of the monitoring surveys, and provides an analysis of the results.
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Recent Performance of and Plasma Outage Studies with the SNS H- Source
Energy Technology Data Exchange (ETDEWEB)
Stockli, Martin P [ORNL; Han, Baoxi [ORNL; Murray Jr, S N [ORNL; Pennisi, Terry R [ORNL; Piller, Chip [ORNL; Santana, Manuel [ORNL; Welton, Robert F [ORNL
2016-01-01
SNS ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised RFQ, which requires higher RF power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ~55-kW 2-MHz plasma pulses reflecting ~90% of the continuous ~300W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly-detuned 13-MHz match. Lowering the H2 also increased the H- beam current to ~55 mA, and increased the transmission by ~7%.
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Space charge and magnet error simulations for the SNS accumulator ring
International Nuclear Information System (INIS)
Beebe-Wang, J.; Fedotov, A.V.; Wei, J.; Machida, S.
2000-01-01
The effects of space charge forces and magnet errors in the beam of the Spallation Neutron Source (SNS) accumulator ring are investigated. In this paper, the focus is on the emittance growth and halo/tail formation in the beam due to space charge with and without magnet errors. The beam properties of different particle distributions resulting from various injection painting schemes are investigated. Different working points in the design of SNS accumulator ring lattice are compared. The simulations in close-to-resonance condition in the presence of space charge and magnet errors are presented. (author)
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Structural and optical characteristics of SnS thin film prepared by SILAR
Directory of Open Access Journals (Sweden)
Mukherjee A.
2015-12-01
Full Text Available SnS thin films were grown on glass substrates by a simple route named successive ion layer adsorption and reaction (SILAR method. The films were prepared using tin chloride as tin (Sn source and ammonium sulfide as sulphur (S source. The structural, optical and morphological study was done using XRD, FESEM, FT-IR and UV-Vis spectrophotometer. XRD measurement confirmed the presence of orthorhombic phase. Particle size estimated from XRD was about 45 nm which fitted well with the FESEM measurement. The value of band gap was about 1.63 eV indicating that SnS can be used as an important material for thin film solar cells. The surface morphology showed a smooth, homogenous film over the substrate. Characteristic stretching vibration mode of SnS was observed in the absorption band of FT-IR spectrum. The electrical activation energy was about 0.306 eV.
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Tarkas, Hemant S.; Marathe, Deepak M.; Mahajan, Mrunal S.; Muntaser, Faisal; Patil, Mahendra B.; Tak, Swapnil R.; Sali, Jaydeep V.
2017-02-01
Synthesis of monomorphic, SnS nanoparticles without using a capping agent is a difficult task with chemical route of synthesis. This paper reports on synthesis of tin monosulfide (SnS) nanopartilces with dimension in the quantum-dot regime using surfactant free microemulsion with single microemulsion scheme. This has been achieved by reaction in microreactors in the CME (C: chlorobenzene, M: methanol and E: ethylene glycol) microemulsion system. This is an easy and controllable chemical route for synthesis of SnS nanoparticles. Nanoparticle diameter showed prominent dependence on microemulsion concentration and marginal dependence on microemulsion temperature in the temperature range studied. The SnS nanoparticles formed with this method form stable dispersion in Tolune.
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International Nuclear Information System (INIS)
Luo, Jin; Zhou, Xiaosong; Ma, Lin; Xu, Xuyao; Wu, Jingxia; Liang, Huiping
2016-01-01
Highlights: • Novel visible-light-driven Ag 2 CrO 4 /SnS 2 composites are synthesized. • Ag 2 CrO 4 /SnS 2 exhibits higher photocatalytic activity than pure Ag 2 CrO 4 and SnS 2 . • Ag 2 CrO 4 /SnS 2 exhibits excellent stability for the photodegradation of MO. • The possible photocatalytic mechanism was discussed in detail. - Abstract: Novel Ag 2 CrO 4 /SnS 2 composites were prepared by a simple chemical precipitation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The visible light photocatalytic tests showed that the Ag 2 CrO 4 /SnS 2 composites enhanced photocatalytic activities for the photodegradation of methyl orange (MO) under visible light irradiation (λ > 420 nm), and the optimum rate constant of Ag 2 CrO 4 /SnS 2 at a weight content of 1.0% Ag 2 CrO 4 for the degradation of MO was 2.2 and 1.5 times larger than that of pure Ag 2 CrO 4 and SnS 2 , respectively. The improved activity could be attributed to high separation efficiency of photogenerated electrons-hole pairs on the interface of Ag 2 CrO 4 and SnS 2 , which arised from the synergistic effect between Ag 2 CrO 4 and SnS 2 . Moreover, the possible photocatalytic mechanism with superoxide radical anions and holes species as the main reactive species in photocatalysis process was proposed on the basis of experimental results.
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Modifications in SnS thin films by plasma treatments
Energy Technology Data Exchange (ETDEWEB)
Martinez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Avellaneda, D. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico)
2012-02-01
The present study shows the modifications of structural, optical and electrical characteristics that occur in tin sulfide (SnS) thin films treated in air and in nitrogen plasma at different pressure conditions. The films were obtained by the chemical bath deposition method, which results in SnS thin films with an orthorhombic crystalline structure, band gap (E{sub g}) of 1.1-1.2 eV, and electrical conductivities ({sigma}) in the order of 10{sup -6} {Omega}{sup -1}cm{sup -1}. The films treated with air plasma at pressures between 1 and 4 Torr, showed the presence of SnS{sub 2}, Sn{sub 2}S{sub 3}, and SnO{sub 2} phases, within the band gap values ranging from 0.9 to 1.5 eV. On the other hand, the films treated with nitrogen plasma presented the same phases, but showed a significant modification in the electrical conductivity, increasing from 10{sup -6} {Omega}{sup -1}cm{sup -1} (as-deposited) up to 10{sup -2}-10{sup -3} {Omega}{sup -1}cm{sup -1} (plasma treated). This result is a suitable range of conductivity for the improvement of the solar cells with SnS as an absorber material. Also, emission spectroscopy measurements were carried out in both air and nitrogen plasma treatments.
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Modulator considerations for the SNS RF system
International Nuclear Information System (INIS)
Tallerico, P.J.; Reass, W.A.
1998-01-01
The Spallation Neutron Source (SNS) is an intense neutron source for neutron scattering experiments. The project is in the research stage, with construction funding beginning next year. The SNS is comprised of an ion source, a 1,000 MeV, H - linear accelerator, an accumulator ring, a neutron producing target, and experimental area to utilize the scattering of the neutrons. The linear accelerator is RF driven, and the peak beam current is 27 mA and the beam duty factor is 5.84%. The peak RF power required is 104 MW, and the H - beam pulse length is 0.97 ms at a 60 Hz repetition rate. The RF pulses must be about 0.1 ms longer than the beam pulses, due to the Q of the accelerating cavities, and the time required to establish control of the cavity fields. The modulators for the klystrons in this accelerator are discussed in this paper. The SNS is designed to be expandable, so the beam power can be doubled or even quadrupled in the future. One of the double-power options is to double the beam pulse length and duty factor. The authors are specifying the klystrons to operate in this twice-duty-factor mode, and the modulator also should be expandable to 2 ms pulses at 60 Hz. Due to the long pulse length and low RF frequency of 805 MHz, the klystron power is specified at 2.5 MW peak, and the RF system will have 56 klystrons at 805 MHz, and three 1.25 MW peak power klystrons at 402.5 MHz for the low energy portion of the accelerator. The low frequency modulators are conventional floating-deck modulation anode control systems
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The US spallation neutron source (SNS) project
International Nuclear Information System (INIS)
Alonso, J.R.
1999-01-01
The SNS is a 1 MW pulsed spallation neutron source that will be sited at Oak Ridge. It will consist of a high-current, normal-conducting linac accelerating an H - beam to 1 GeV, an accumulator ring which compresses each 1 ms linac pulse into a 600 ns bunch which is then extracted in a single turn onto a liquid mercury target. Neutron pulses emerge at a 60 Hz rate from the two ambient, and two cryogenic moderators. Eighteen beam ports surrounding the target station are available for neutron-scattering instrumentation. Funds for ten instruments are included in the construction project; these instruments will provide basic measurement capability for the many and varied research activities at the SNS facility. The new spallation source is being built by a consortium of laboratories; the partners are LBNL, LANL, BNL, ANL and ORNL. The breadth and depth of experience and resources brought by such a wide-spread team offers very significant advantages. Construction will start in October of 1998, operation will begin in October, 2005. (J.P.N.)
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Development of N-layer materials for SNS junction and SQUID applications
International Nuclear Information System (INIS)
Zhou, J.P.; McDevitt, J.T.; Jia, Q.
1997-01-01
Materials characteristics including water reactivity, oxygen loss, electromigration of oxide ions, and interfacial reactivity problems have plagued attempts to produce reliable and reproducible cuprate SNS superconductor junctions. In an effort to solve some of these formidable problems, new N-layer compounds from the family of R 1-x Ca x Ba 2-y La y Cu 3-z M z O 7-δ (R = Y, Gd and Pr; M = Co, Ni and Zn; 0 2 Cu 3 O 7-δ phase and the modified materials exhibit enhanced durability properties. The compounds have been utilized to make both SNS junctions and SQUID devices
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A nanoscale ordered materials diffractometer for the SNS
International Nuclear Information System (INIS)
Neuefeind, Joerg; Chipley, Kenneth K.; Tulk, Chris A.; Simonson, J. Michael; Winokur, Michael J.
2006-01-01
The Nanoscale Ordered Materials Diffractometer (NOMAD) is one of five neutron scattering instruments being managed within the Spallation Neutron Source (SNS) Instruments-Next Generation (SING) project. NOMAD is designed as a high-flux, medium-resolution diffractometer using a large bandwidth of neutron energies and extensive detector coverage to perform structural determinations of local order in crystalline and amorphous materials. The instrument will enable studies of a large variety of samples ranging from liquids, solutions, glasses, polymers, and nanocrystalline materials to long-range ordered crystals and will allow unprecedented access to high-resolution pair distribution functions, small-contrast isotope substitution experiments, small sample sizes, and parametric studies. Project completion for the instrument is anticipated in 2010 and a review of the design status will be given
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SNS Central Helium Liquefier spare Carbon Bed installation and commissioning
Energy Technology Data Exchange (ETDEWEB)
Degraff, Brian D. [ORNL; Howell, Matthew P. [ORNL; Kim, Sang-Ho [ORNL; Neustadt, Thomas S. [ORNL
2017-07-01
The Spallation Neutron Source (SNS) Central Helium Liquefier (CHL) at Oak Ridge National Laboratory (ORNL) has been without major operations downtime since operations were started back in 2006. This system utilizes a vessel filled with activated carbon as the final major component to remove oil vapor from the compressed helium circuit prior to insertion into the system's cryogenic cold box. The need for a spare carbon bed at SNS due to the variability of carbon media lifetime calculation to adsorption efficiency will be discussed. The fabrication, installation and commissioning of this spare carbon vessel will be presented. The novel plan for connecting the spare carbon vessel piping to the existing infrastructure will be presented.
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Implementation of SNS Model for Intrusion Prevention in Wireless Local Area Network
DEFF Research Database (Denmark)
Isah, Abdullahi
The thesis has proposed and implemented a so-called SNS (Social network security) model for intrusion prevention in the Wireless Local Area Network of an organization. An experimental design was used to implement and test the model at a university in Nigeria.......The thesis has proposed and implemented a so-called SNS (Social network security) model for intrusion prevention in the Wireless Local Area Network of an organization. An experimental design was used to implement and test the model at a university in Nigeria....
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Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation
International Nuclear Information System (INIS)
Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook
2017-01-01
Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.
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Impact of high temperature and short period annealing on SnS films deposited by E-beam evaporation
Energy Technology Data Exchange (ETDEWEB)
Gedi, Sreedevi; Reddy, Vasudeva Reddy Minnam; Kang, Jeong-yoon; Jeon, Chan-Wook, E-mail: cwjeon@ynu.ac.kr
2017-04-30
Highlights: • Preparation SnS films using electron beam evaporation at room temperature. • SnS films were annealed at a high temperaure for different short period of times. • The films showed highly oriented (111) planes with orthorhombic crystal structure. • Surface morphology showed bigger and faceted grains embedded in orthorombic. • The TEM confirmed that big orthorombic slabs had single-crystalline nature. - Abstract: Thin films of SnS were deposited on Mo-substrate using electron beam evaporation at room temperature. As-deposited SnS films were annealed at a constant high temperaure of 860 K for different short period of times, 1 min, 3 min, and 5 min. The impact of heat treatment period on the physical properties of SnS films was investigated using appropriate characterization tools. XRD analysis revealed that the films were highly oriented along (111) plane with orthorhombic crystal structure. Surface morphology of as-deposited SnS films showed an identical leaf texture where as the annealed films showed large orthorombic slab shape grains in adidition to the leaf shape grains, which indicates the significance of short period annealing at high temperature. The transmission electron microscopy confirmed that those large orthorombic slabs had single-crystalline nature. The results emphasized that the short period annealing treatment at high temperature stimulated the growth of film towards the single crystallinity.
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SNS RING STUDY AT THE AGS BOOSTER.
Energy Technology Data Exchange (ETDEWEB)
ZHANG, S.Y.; AHRENS, L.; BEEBE-WANG, J.; BLASKIEWICZ, M.; FEDOTOV, A.; GARDNER, C.; LEE, Y.Y.; LUCCIO, A.; MALITSKY, N.; ROSER, T.; WENG, W.T.; WEI, J.; ZENO, K.; REECE, K.; WANG, J.G.
2000-06-30
During the g-2 run at the BNL AGS in early 2000, a 200 MeV storage-ring-like magnetic cycle has been set-up and tuned at the Booster in preparing for the Spallation Neutron Source (SNS) accumulator ring study. In this article, we report the progress of the machine set-up, tuning, some preliminary studies, and the future plan.
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Effect of van der Waals interaction on the properties of SnS2 layered semiconductor
International Nuclear Information System (INIS)
Seminovski, Y.; Palacios, P.; Wahnón, P.
2013-01-01
Nowadays, dispersion correction applied on layered semiconductors is a topic of interest. Among the known layered semiconductors, SnS 2 polytypes are wide gap semiconductors with a van der Waals interaction between their layers, which could form good materials to be used in photovoltaic applications. The present work gives an approach to the SnS 2 geometrical and electronic characterization using an empirical dispersion correction added to the Perdew–Burke–Ernzerhof functional and subsequent actualization of the electronic charge density using the screened hybrid Heyd–Scuseria–Ernzerhof functional using a density functional code. The obtained interlayer distance and band-gap are in good agreement with experimental values when van der Waals dispersion forces are included. - Highlights: ► Tin disulphide (SnS 2 ) has been calculated using density functional theory methods. ► A dispersion correction was also applied for two different SnS 2 polytypes. ► Geometrical parameters and band-gaps were obtained using both approaches. ► Our calculations give a good agreement of the computed band gap with experiment
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DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS
International Nuclear Information System (INIS)
HE, P.; HSEUH, H.C.; MAPES, M.; TODD, R.; WEISS, D.
2001-01-01
The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with ∼100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented
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Ferrite measurements for SNS accelerating cavities
International Nuclear Information System (INIS)
Bendall, R.G.; Church, R.A.
1979-03-01
The RF system for the SNS has six double accelerating cavities each containing seventy ferrite toroids. Difficulties experienced in obtaining toroids to the required specifications are discussed and the two toroid test cavity built to test those supplied is described. Ferrite measurements are reported which were undertaken to measure; (a) μQf as a function of frequency and RF field level and (b) bias current as a function of frequency for different ranges of ferrite permeability μ. (U.K.)
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Study of Arc-Related RF Faults in the CEBAF Cryomodules
Energy Technology Data Exchange (ETDEWEB)
Douglas Curry; Ganapati Myneni; Ganapati Rao Myneni; John Musson; Thomas Powers; Timothy Whitlatch; Isidoro Campisi; Haipeng Wang
2004-07-01
A series of measurements has been conducted on two superconducting radio-frequency (RF) cavity pairs, installed in cryomodules and routinely operated in the Continuous Electron Beam Accelerator Facility, in order to study the RF-vacuum interaction during an RF fault. These arc-related fault rates increase with increasing machine energy, contribute to system downtime, and directly affect the accelerator's availability. For this study, the fundamental power coupler waveguides have been instrumented with vacuum gauges, additional arc detectors, additional infrared sensors, and temperature sensors in order to measure the system response during both steady-state operations and RF fault conditions. Residual gas analyzers have been installed on the waveguide vacuum manifolds to monitor the gas species present during cooldown, RF processing, and operation. Measurements of the signals are presented, a comparison with analysis is shown and results are discussed. The goal of this study is to characterize the RF-vacuum interaction during normal operations. With a better understanding of the installed system response, methods for reducing the fault rate may be devised, ultimately leading to improvements in availability.
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FANG, CM; ETTEMA, ARHF; HAAS, C; WIEGERS, GA; VANLEUKEN, H; DEGROOT, RA
1995-01-01
In order to understand the electronic structure of the misfit-layer compound (SnS)(1.17)NbS2 we carried out an ab initio band-structure calculation of the closely related commensurate compound (SnS)(1.20)NbS2. The band structure is compared with calculations for NbS2 and for hypothetical SnS with
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Performance of 3.9 GHz SRF cavities at Fermilab's ILCTA_MDB nhorizontal test stand
Energy Technology Data Exchange (ETDEWEB)
Harms, Elvin; Hocker, Andy; /Fermilab
2008-08-01
Fermilab is building a cryomodule containing four 3.9 GHz superconducting radio frequency (SRF) cavities for the Free electron LASer in Hamburg (FLASH) facility at the Deutsches Elektronen-SYnchrotron (DESY) laboratory. Before assembling the cavities into the cryomodule, each individual cavity is tested at Fermilab's Horizontal Test Stand (HTS). The HTS provides the capability to test fully-dressed SRF cavities at 1.8 K with high-power pulsed RF in order to verify that the cavities achieve performance requirements under these conditions. The performance at the HTS of the 3.9 GHz cavities built for FLASH is presented here.
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SNS Diagnostics Tools for Data Acquisition and Display
Sundaram, Madhan; Long, Cary D
2005-01-01
The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1.0 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based and will run Windows for its OS and LabVIEW as its programming language. The diagnostics platform as well as other control systems and operator consoles use the Channel Access (CA) protocol of the Experimental Physics and Industrial Control System (EPICS) to communicate. This paper describes the tools created to evaluate the diagnostic instrument using our standard programming environment, LabVIEW. The tools are based on the LabVIEW Channel Access library and can run on Windows, Linux, and Mac OS X. The data-acquisition tool uses drop and drag to select process variables organized by instrument, accelerator component, or beam parameters. The data can be viewed on-line and logged to disk for later ...
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High Power RF Test Facility at the SNS
Kang, Yoon W; Campisi, Isidoro E; Champion, Mark; Crofford, Mark; Davis, Kirk; Drury, Michael A; Fuja, Ray E; Gurd, Pamela; Kasemir, Kay-Uwe; McCarthy, Michael P; Powers, Tom; Shajedul Hasan, S M; Stirbet, Mircea; Stout, Daniel; Tang, Johnny Y; Vassioutchenko, Alexandre V; Wezensky, Mark
2005-01-01
RF Test Facility has been completed in the SNS project at ORNL to support test and conditioning operation of RF subsystems and components. The system consists of two transmitters for two klystrons powered by a common high voltage pulsed converter modulator that can provide power to two independent RF systems. The waveguides are configured with WR2100 and WR1150 sizes for presently used frequencies: 402.5 MHz and 805 MHz. Both 402.5 MHz and 805 MHz systems have circulator protected klystrons that can be powered by the modulator capable of delivering 11 MW peak and 1 MW average power. The facility has been equipped with computer control for various RF processing and complete dual frequency operation. More than forty 805 MHz fundamental power couplers for the SNS superconducting linac (SCL) cavitites have been RF conditioned in this facility. The facility provides more than 1000 ft2 floor area for various test setups. The facility also has a shielded cave area that can support high power tests of normal conducti...
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SNS AC Power Distribution and Reliability of AC Power Supply
Holik, Paul S
2005-01-01
The SNS Project has 45MW of installed power. A design description under the Construction Design and Maintenance (CDM) with regard to regulations (OSHA, NFPA, NEC), reliability issues and maintenance of the AC power distribution system are herewith presented. The SNS Project has 45MW of installed power. The Accelerator Systems are Front End (FE)and LINAC KLYSTRON Building (LK), Central Helium Liquefier (CHL), High Energy Beam Transport (HEBT), Accumulator Ring and Ring to Target Beam Transport (RTBT) Support Buildings have 30MW installed power. FELK has 16MW installed, majority of which is klystron and magnet power supply system. CHL, supporting the super conducting portion of the accelerator has 7MW installed power and the RING Systems (HEBT, RING and RTBT) have also 7MW installed power.*
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CORRECTION SYSTEMS UPGRADE FOR THE SNS RING
International Nuclear Information System (INIS)
PAPAPHILIPPOU, Y.; GARDNER, C.J.; LEE, Y.Y.; WEI, J.
2001-01-01
In view of the changes in the design of the SNS ring from the original FODO lattice [l] to the 220m hybrid lattice [2] and finally 1.3GeV compatible 248m ring [3], complementary studies have been undertaken, in order to upgrade its correction packages. We review the evolution of the correction systems and present the accelerator physics studies for the adopted schemes and powering plan
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Directory of Open Access Journals (Sweden)
Yanli Zhou
2018-02-01
Full Text Available The three-dimensional (3D SnS decorated carbon nano-networks (SnS@C were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g−1 for SnS@C composites can be obtained at 100 mA·g−1 after 100 cycles. Even cycled at a high current density of 2 A·g−1, the reversible capacity of this composite can be maintained at 610 mAh·g−1 after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g−1, and it retains a reversible capacity of 186 mAh·g−1 at 100 mA·g−1 after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles.
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Cryogenic test of the 4 K / 2 K insert for the ARIEL e-Linac cryomodule
International Nuclear Information System (INIS)
Laxdal, R. E.; Ma, Y.; Harmer, P.; Kishi, D.; Koveshnikov, A.; Muller, N.; Vrielink, A.; O'Brien, M.; Ahammed, M.
2014-01-01
The ARIEL project at TRIUMF requires a 50 MeV superconducting electron linac consisting of five nine cell 1.3 GHz cavities divided into three cryomodules with one, two and two cavities in each module respectively. LHe is distributed in parallel to each module at 4 K and at ∼1.2 bar. Each module has a cryogenic insert on board that receives the 4 K liquid and produces 2 K into a cavity phase separator. The module combines a 4 K phase separator, a plate and fin heat exchanger from DATE and a J-T valve expanding into the 2 K phase separator. The unit also supplies 4 K liquid to thermal intercepts in the module in siphon loops that return the vaporized liquid to the 4 K reservoir. For testing purposes the unit is outfitted with a dummy 2 K phase separator and thermal intercepts with variable heaters that mimic the final heat loads in order to test the cryogenic performance. The design of the 4 K / 2 K insert, the results of the cold tests and a summary of the test infrastructure including cryogenics services will be presented
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Cryogenic test of the 4 K / 2 K insert for the ARIEL e-Linac cryomodule
Energy Technology Data Exchange (ETDEWEB)
Laxdal, R. E.; Ma, Y.; Harmer, P.; Kishi, D.; Koveshnikov, A.; Muller, N.; Vrielink, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada); O' Brien, M. [University of British Columbia, Vancouver (Canada); Ahammed, M. [Variable Energy Cyclotron Center, Kolkata (India)
2014-01-29
The ARIEL project at TRIUMF requires a 50 MeV superconducting electron linac consisting of five nine cell 1.3 GHz cavities divided into three cryomodules with one, two and two cavities in each module respectively. LHe is distributed in parallel to each module at 4 K and at ∼1.2 bar. Each module has a cryogenic insert on board that receives the 4 K liquid and produces 2 K into a cavity phase separator. The module combines a 4 K phase separator, a plate and fin heat exchanger from DATE and a J-T valve expanding into the 2 K phase separator. The unit also supplies 4 K liquid to thermal intercepts in the module in siphon loops that return the vaporized liquid to the 4 K reservoir. For testing purposes the unit is outfitted with a dummy 2 K phase separator and thermal intercepts with variable heaters that mimic the final heat loads in order to test the cryogenic performance. The design of the 4 K / 2 K insert, the results of the cold tests and a summary of the test infrastructure including cryogenics services will be presented.
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State of the art of multicell SC cavities and perspectives
International Nuclear Information System (INIS)
Peter Kneisel
2002-01-01
Superconducting cavity technology has made major progresses in the last decade with the introduction of high purity niobium on an industrial scale and, at the same time, by an improved understanding of the limiting processes in cavity performance, such as multipacting, field emission loading and thermal break-down. Multicell niobium cavities for beta = 1 particle acceleration, e.g. for the TESLA project, are routinely exceeding gradients of Eacc = 20 MV/m after the application of surface preparation techniques such as buffered chemical polishing or electropolishing, high pressure ultrapure water rinsing, UHV heat treatment and clean room assembly. The successes of the technology for beta = 1 accelerators has triggered a whole set of possible future applications for beta < 1 particle acceleration such as spallation neutron sources (SNS, ESS), transmutation of nuclear waste (TRASCO, ASH) or rare isotopes (RIA). The most advanced of these projects is SNS now under construction at Oak Ridge National Laboratory. This paper will review the technical solutions adopted to advance SRF technology and their impact on cavity performance, based on the SNS prototyping efforts. 2K at these high gradients are no longer out of reach. For the accelerator builder the challenge remains to come up with a good and reasonable design, which takes into account the status of the technology and does not over-estimate the achievable cavity performances in a large assembly such as, e.g., a multi-cavity cryo-module. In the following the criteria for multi-cell sc cavity design are reviewed and it is attempted to give a snapshot of the present status of multi-cell cavity performances
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Energy Technology Data Exchange (ETDEWEB)
Gómez, A. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Martínez, H., E-mail: hm@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Calixto-Rodríguez, M. [Centro de Investigación en Energía, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Avellaneda, D. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, México (Mexico); Reyes, P.G. [Facultad de Ciencias, Universidad Autónoma del Estado de México, Estado de México, México (Mexico); Flores, O. [Instituto de Ciencias Fisicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62251, Cuernavaca, Morelos (Mexico)
2013-06-15
In this paper, we report modifications of structural and optical, electrical properties that occur in tin sulphide (SnS) treated in O{sub 2} plasma. The SnS thin films were deposited by chemical bath deposition technique. The samples were treated in an O{sub 2} plasma discharge at 3 Torr of pressure discharge, a discharge voltage of 2.5 kV and 20 mA of discharge current. The prepared and treated thin films were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The photoconductivity and electrical effects of SnS have been studied. The SnS thin films had an orthorhombic crystalline structure. With the plasma treatment the optical gap and electrical properties of the SnS films changed from 1.61 to 1.84 eV, for 3.9 × 10{sup 5} to 10.42 Ω cm, respectively. These changes can be attributed to an increase in electron density, percolation effects due to porosity, surface degradation/etching that is an increase in surface roughness, where some structural changes related to crystallinity occurs like a high grain size as revealed by SEM images.
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Higher order mode analysis of the SNS superconducting linac
Sang Ho Kim; Dong Jeon; Sundelin, R
2001-01-01
Higher order modes (HOM's) of monopoles, dipoles, quadrupoles and sextupoles in beta =0.61 and beta =0.81 6-cell superconducting (SC) cavities for the Spallation Neutron Source (SNS) project, have been found up to about 3 GHz and their properties such as R/Q, trapping possibility, etc have been figured out concerning manufacturing imperfection. The main issues of HOM's are beam instabilities (published separately) and HOM induced power especially from TM monopoles. The time structure of SNS beam has three different time scales of pulses, which are micro-pulse, midi-pulse and macropulse. Each time structure will generate resonances. When a mode is near these resonance frequencies, the induced voltage could be large and accordingly the resulting HOM power. In order to understand the effects from such a complex beam time structure on the mode excitation and resulting HOM power, analytic expressions are developed. With these analytic expressions, the induced HOM voltage and HOM power were calculated by assuming e...
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A facile inexpensive route for SnS thin film solar cells with SnS{sub 2} buffer
Energy Technology Data Exchange (ETDEWEB)
Gedi, Sreedevi [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Minna Reddy, Vasudeva Reddy, E-mail: drmvasudr9@gmail.com [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Pejjai, Babu [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India); Jeon, Chan-Wook [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Park, Chinho, E-mail: chpark@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, 280Daehak-ro, Gyeongsan 712-749, Republic of Korea (Korea, Republic of); Ramakrishna Reddy, K.T., E-mail: ktrkreddy@gmail.com [Solar Photovoltaic Laboratory, Department of Physics, Sri Venkateswasra University, Tirupati 517 502 (India)
2016-05-30
Graphical abstract: PYS spectra of SnS/SnS{sub 2} interface and the related band diagram. - Highlights: • A low cost SnS solar cell is developed using chemical bath deposition. • We found E{sub I} & χ of SnS (5.3 eV & 4.0 eV) and SnS{sub 2} (6.9 eV & 4.1 eV) films from PYS. • Band offsets of 0.1 eV (E{sub c}) and 1.6 eV (E{sub v}) are estimated for SnS/SnS{sub 2} junction. • SnS based solar cell showed a conversion efficiency of 0.51%. - Abstract: Environment-friendly SnS based thin film solar cells with SnS{sub 2} as buffer layer were successfully fabricated from a facile inexpensive route, chemical bath deposition (CBD). Layer studies revealed that as-grown SnS and SnS{sub 2} films were polycrystalline; (1 1 1)/(0 0 1) peaks as the preferred orientation; 1.3 eV/2.8 eV as optical band gaps; and showed homogeneous microstructure with densely packed grains respectively. Ionization energy and electron affinity values were found by applying photoemission yield spectroscopy (PYS) to the CBD deposited SnS and SnS{sub 2} films for the first time. These values obtained as 5.3 eV and 4.0 eV for SnS films; 6.9 eV and 4.1 eV for SnS{sub 2} films. The band alignment of SnS/SnS{sub 2} junction showed TYPE-II heterostructure. The estimated conduction and valance band offsets were 0.1 eV and 1.6 eV respectively. The current density–voltage (J–V) measurements of the cell showed open circuit voltage (V{sub oc}) of 0.12 V, short circuit current density (J{sub sc}) of 10.87 mA cm{sup −2}, fill factor (FF) of 39% and conversion efficiency of 0.51%.
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Cooling for SC devices of test cryomodule for ADS Injector II at IMP
Energy Technology Data Exchange (ETDEWEB)
Wang, L.; Wang, S. Y.; Sun, S.; Wang, S. H.; Liu, Y. Y. [Shanghai Institute of Applied Physics, CAS, Shanghai 201204 (China); Guo, X. L. [JiangSu University, Zhenjiang 212013 (China)
2014-01-29
The superconducting half-wave resonance cavities connected in series with superconducting solenoids will be applied to the Injector II of the Accelerator Driven Sub-critical System (ADS) to be built at the Modern Physics Institute, China. A test system has been developed for the purpose of performance test of the HWR cavities as well as validating the relevant technique for cooling the cavity and the solenoids together. It mainly comprises a cryogenic valve box (TVB), a test cryomodule (TCM1) and transfer lines. The TCM1 includes one HWR cavity, two superconducting solenoids, one cold BPM and their cooling system. The design of the TCM1 cryostat was carried out by the Shanghai Institute of Applied Physics (SINAP), CAS. Both the cavity and the solenoids will work at 4.4 K by bath cooling. The fast cooling down for the cavity from around 100 K to 120 K is required to avoid degrading of the cavity performance. After cool down and before energization, the solenoids should be warmed up to above 10 K and re-cooled down for the purpose of degaussing. The TCM1 can not only be cooled by using the dewar-filling system, but also operated by the refrigerator system. For the purpose of reducing the heat loads to the cold mass at 4 K from room temperature, thermal radiation shields cooled by liquid nitrogen flowing in tubing were employed. This paper presents the design details of cooling circuits and thermal shields of the TCM1 as well as related calculations and analyses.
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Overcoming the efficiency limitations of SnS2 nanoparticle-based bulk heterojunction solar cells
Tam Nguyen Truong, Nguyen; Kieu Trinh, Thanh; Thanh Hau Pham, Viet; Smith, Ryan P.; Park, Chinho
2018-04-01
This study examined the effects of heat treatment, the electron transport layer, and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) incorporation on the performance of hybrid bulk heterojunction (BHJ) solar cells composed of tin disulfide (SnS2) nanoparticles (NPs) and low band gap energy polymers poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b3,4-b‧]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) or poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PBT7). Inserting an electron transport layer (ETL) (i.e., ZnO) on the top of the photoactive layer improved the surface morphology of the photoactive layer, which led to an improvement in charge transport. Moreover, adding a suitable amount of PCBM to the SnS2/polymer active layer enhanced the device performance, such as short circuit current density (J sc) and power conversion efficiency (PCE). In particular, adding 0.5 mg of PCBM to the composite solution led to a 25% and 1.5% improvement in the J sc value and PCE, respectively. The enhanced performance was due mainly to the improvements in the surface morphology of the photoactive layer, charge carrier mobility within the donor-acceptor interface, and carrier collection efficiency at the cathode.
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Mechanical Design of a New Injector Cryomodule 2-Cell Cavity at CEBAF
Energy Technology Data Exchange (ETDEWEB)
Cheng, Guangfeng G. [JLAB; Henry, James E. [JLAB; Mammosser, John D. [JLAB; Rimmer, Robert A. [JLAB; Wang, Haipeng [JLAB; Wiseman, Mark A. [JLAB; Yang, Shuo [JLAB
2013-12-01
As a part of Jefferson Lab’s 12 GeV upgrade, a new injector superconducting RF cryomodule is required. This unit consists of a 2-cell and 7-cell cavity, with the latter being refurbished from an existing cavity. The new 2-cell cavity requires electromagnetic design and optimization followed by mechanical design analyses. The electromagnetic design is reported elsewhere. This paper aims to present the procedures and conclusions of the analyses on cavity tuning sensitivity, pressure sensitivity, upset condition pressure induced stresses, and structural vibration frequencies. The purposes of such analyses include: 1) provide reference data for cavity tuner design; 2) examine the structural integrity of the cavity; and 3) evaluate the 2-cell cavity’s resistance to microphonics. Design issues such as the location of stiffening rings, effect of tuner stiffness on cavity stress, choice of cavity wall thickness, etc. are investigated by conducting extensive finite element analyses. Progress in fabrication of the 2-cell cavity is also reported.
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Fang, C.M.; Ettema, A.R.H.F.; Haas, C.; Wiegers, G.A.; Leuken, H. van; Groot, R.A. de
1995-01-01
In order to understand the electronic structure of the misfit-layer compound (SnS)1.17NbS2 we carried out an ab initio band-structure calculation of the closely related commensurate compound (SnS)1.20NbS2. The band structure is compared with calculations for NbS2 and for hypothetical SnS with
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Wavefunction and energy of the 1s22sns configuration in a beryllium atom
International Nuclear Information System (INIS)
Huang Shizhong; Ma Kun; Yu Jiaming; Liu Fen
2008-01-01
A new set of trial functions for 1s 2 2sns configurations in a beryllium atom is suggested. A Mathematica program based on the variational method is developed to calculate the wavefunctions and energies of 1s 2 2sns (n = 3–6) configurations in a beryllium atom. Non-relativistic energy, polarization correction and relativistic correction which include mass correction, one-and two-body Darwin corrections, spin-spin contact interaction and orbit-orbit interaction, are calculated respectively. The results are in good agreement with experimental data. (atomic and molecular physics)
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DESIGN OF BEAM-EXTRACTION SEPTUM MAGNET FOR THE SNS
International Nuclear Information System (INIS)
TSOUPAS, N.; LEE, Y.Y.; RANK, J.; TUOZZOLO, J.
2001-01-01
The beam-extraction process from the SNS accumulator ring [1,2] requires a Lambertson septum magnet. In this paper we discuss the geometrical and magnetic field requirements of the magnet and present results obtained from two and three dimensional magnetic field calculations that shows the field quality in the regions of interest of the septum magnet
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Synthesis and characterization of electrodeposited SnS films
International Nuclear Information System (INIS)
Jim, W. Y.; Sun, Y. C.; Djurišić, A. B.; Chan, W. K.
2013-01-01
Here we systematically investigated the effect of solution concentration and growth temperature on the properties of SnS thin films. The properties of deposited films were investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy. We found that sample quality is strongly affected by deposition conditions and that the sample composition exhibits strong temperature dependence. Detailed discussion of material properties dependence on the growth conditions is given
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Carbon dots decorated vertical SnS_2 nanosheets for efficient photocatalytic oxygen evolution
International Nuclear Information System (INIS)
Cheng, Zhongzhou; Wang, Fengmei; Shifa, Tofik Ahmed; Liu, Kaili; Huang, Yun; Jiang, Chao; He, Jun; Liu, Quanlin
2016-01-01
Metal sulfides are highly desirable materials for photocatalytic water splitting because of their appropriate energy bands. However, the poor stability under light illumination in water hinders their wide applications. Here, two-dimensional SnS_2 nanosheets, along with carbon dots of the size around 10 nm, are uniformly grown on fluorine doped tin oxide glasses with a layer of nickel nanoparticles. Significantly, strong light absorption and enhanced photocurrent density are achieved after integration of SnS_2 nanosheets with carbon dots. Notably, the rate of oxygen evolution reached up to 1.1 mmol g"−"1 h"−"1 under simulated sunlight irradiation featuring a good stability.
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Dynamic Visualization of SNS Diagnostics Summary Report and System Status
Blokland, Willem; Long, Cary D; Murphy, Darryl J; Purcell, John D; Sundaram, Madhan
2005-01-01
The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based running Embedded Windows XP and LabVIEW. The diagnostics instruments communicate with the control system using the Channel Access (CA) protocol of the Experimental Physics and Industrial Control System (EPICS). This paper describes the Diagnostics Group's approach to collecting data from the instruments, processing it, and presenting live in a summarized way over the web. Effectively, adding a supervisory level to the diagnostics instruments. One application of this data mining is the "Diagnostics Status Page" that summarizes the insert-able devices, transport efficiencies, and the mode of the accelerator in a compact webpage. The displays on the webpage change automatically to show the latest and/o...
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Löschmann, Nadine; Michaelis, Martin; Rothweiler, Florian; Zehner, Richard; Cinatl, Jaroslav; Voges, Yvonne; Sharifi, Mohsen; Riecken, Kristoffer; Meyer, Jochen; von Deimling, Andreas; Fichtner, Iduna; Ghafourian, Taravat; Westermann, Frank; Cinatl, Jindrich
2013-01-01
Novel treatment options are needed for the successful therapy of patients with high-risk neuroblastoma. Here, we investigated the cyclin-dependent kinase (CDK) inhibitor SNS-032 in a panel of 109 neuroblastoma cell lines consisting of 19 parental cell lines and 90 sublines with acquired resistance to 14 different anticancer drugs. Seventy-three percent of the investigated neuroblastoma cell lines and all four investigated primary tumor samples displayed concentrations that reduce cell viability by 50% in the range of the therapeutic plasma levels reported for SNS-032 (<754 nM). Sixty-two percent of the cell lines and two of the primary samples displayed concentrations that reduce cell viability by 90% in this concentration range. SNS-032 also impaired the growth of the multidrug-resistant cisplatin-adapted UKF-NB-3 subline UKF-NB-3rCDDP1000 in mice. ABCB1 expression (but not ABCG2 expression) conferred resistance to SNS-032. The antineuroblastoma effects of SNS-032 did not depend on functional p53. The antineuroblastoma mechanism of SNS-032 included CDK7 and CDK9 inhibition-mediated suppression of RNA synthesis and subsequent depletion of antiapoptotic proteins with a fast turnover rate including X-linked inhibitor of apoptosis (XIAP), myeloid cell leukemia sequence 1 (Mcl-1), baculoviral IAP repeat containing 2 (BIRC2; cIAP-1), and survivin. In conclusion, CDK7 and CDK9 represent promising drug targets and SNS-032 represents a potential treatment option for neuroblastoma including therapy-refractory cases. PMID:24466371
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Characterization of hydrothermally synthesized SnS nanoparticles for solar cell application
Rajwar, Birendra Kumar; Sharma, Shailendra Kumar
2018-05-01
In the present study, SnS nanoparticles were synthesized by simple hydrothermal method using stannous chloride and thiourea as tin (Sn) and sulfur (S) precursor respectively. Synthesized nanoparticles were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy and UV-Vis Spectroscopy techniques. XRD pattern reveals that as-prepared nanoparticles exhibit orthorhombic structure. Average particles size was calculated using Scherrer's formula and found to be 23 nm. FESEM image shows that the as-prepared nanoparticles are in plate like structure. Direct optical band gap (Eg) of as-synthesized nanoparticles was calculated through UV-Vis Spectroscopy measurement and found to be 1.34 eV, which is near to optimum need for photovoltaic solar energy conversion (1.5 eV). Thus this SnS, narrowband gap semiconductor material can be applied as an alternative absorber material for solar cell application.
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Energy Technology Data Exchange (ETDEWEB)
Baby, Benjamin Hudson; Mohan, D. Bharathi, E-mail: d.bharathimohan@gmail.com
2017-05-01
We report the formation of single phase of SnS nanostructure through PVP assisted polyol synthesis by varying the source concentration ratio (Sn:S) from 1:1M to 1:12M. The effect of PVP concentration and reaction medium towards the preparation of SnS nanostructure is systematically studied through confocal Raman spectrometer, X-ray diffraction, thermogravimetry analysis, scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis–NIR absorption and fluorescence spectrophotometers. The surface morphology of SnS nanostructure changes from nanorods to spherical shape with increasing PVP concentration from 0.15M to 0.5M. Raman analysis corroborates that Raman active modes of different phases of Sn-S are highly active when Raman excitation energy is slightly greater than the energy band gap of the material. The presence of intrinsic defects and large number of grain boundaries resulted in an improved thermal stability of 20 °C during the phase transition of α-SnS. Band gap calculation from tauc plot showed the direct band gap of 1.5 eV which is attributed to the single phase of SnS, could directly meet the requirement of an absorber layer in thin film solar cells. Finally, we proposed an energy band diagram for as synthesized single phase SnS nanostructure based on the experimental results obtained from optical studies showing the energy transitions attributed to band edge transition and also due to the presence of intrinsic defects. - Highlights: • PVP stabilizes the orthorhombic (α) phase of SnS. • Optical band gap of P type SnS tuned by PVP for photovoltaic applications. • The formation of Sn rich SnS phase is investigated through XPS analysis. • Intrinsic defects enhance the thermal stability of α-SnS. • The feasibility of energy transition liable to point defects is discussed.
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Random Access Performance of Distributed Sensors Attacked by Unknown Jammers
Directory of Open Access Journals (Sweden)
Dae-Kyo Jeong
2017-11-01
Full Text Available In this paper, we model and investigate the random access (RA performance of sensor nodes (SN in a wireless sensor network (WSN. In the WSN, a central head sensor (HS collects the information from distributed SNs, and jammers disturb the information transmission primarily by generating interference. In this paper, two jamming attacks are considered: power and code jamming. Power jammers (if they are friendly jammers generate noises and, as a result, degrade the quality of the signal from SNs. Power jamming is equally harmful to all the SNs that are accessing HS and simply induces denial of service (DoS without any need to hack HS or SNs. On the other hand, code jammers mimic legitimate SNs by sending fake signals and thus need to know certain system parameters that are used by the legitimate SNs. As a result of code jamming, HS falsely allocates radio resources to SNs. The code jamming hence increases the failure probability in sending the information messages, as well as misleads the usage of radio resources. In this paper, we present the probabilities of successful preamble transmission with power ramping according to the jammer types and provide the resulting throughput and delay of information transmission by SNs, respectively. The effect of two jamming attacks on the RA performances is compared with numerical investigation. The results show that, compared to RA without jammers, power and code jamming degrade the throughput by up to 30.3% and 40.5%, respectively, while the delay performance by up to 40.1% and 65.6%, respectively.
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Phase-tunable Majorana bound states in a topological N-SNS junction
DEFF Research Database (Denmark)
Hansen, Esben Bork; Danon, Jeroen; Flensberg, Karsten
2016-01-01
We theoretically study the differential conductance of a one-dimensional normal-superconductor-normal-superconductor (N-SNS) junction with a phase bias applied between the two superconductors. We consider specifically a junction formed by a spin-orbit coupled semiconducting nanowire with regions ...
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Halo and space charge issues in the SNS Ring
International Nuclear Information System (INIS)
Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.
2000-01-01
The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring
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Halo and space charge issues in the SNS Ring
Energy Technology Data Exchange (ETDEWEB)
Fedotov, A.V.; Abell, D.T.; Beebe-Wang, J.; Lee, Y.Y.; Malitsky, N.; Wei, J.; Gluckstern, R.L.
2000-06-30
The latest designs for high-intensity proton rings require minimizing beam-induced radioactivation of the vacuum chamber. Although the tune depression in the ring is much smaller than in high-intensity linacs, space-charge contributions to halo formation and, hence, beam loss may be significant. This paper reviews our current understanding of halo formation issues for the Spallation Neutron Source (SNS) accumulator ring.
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Directory of Open Access Journals (Sweden)
Lee eSoon Li
2016-04-01
Full Text Available Perception of the autonomy and relatedness of the self may be influenced by one’s experiences and social expectations within a particular cultural setting. The present research examined the role of culture and the Autonomous-Related self-construal in predicting for different aspects of Social Networking Sites (SNS usage in three Asian countries, especially focusing on those aspects serving interpersonal goals. Participants in this cross-cultural study included 305 university students from Malaysia (n = 105, South Korea (n = 113, and China (n = 87. The study explored specific social and interpersonal behaviors on SNS, such as browsing the contacts’ profiles, checking for updates, and improving contact with SNS contacts, as well as the intensity of SNS use, hypothesizing that those with high intensity of use in the Asian context may be doing so to achieve the social goal of maintaining contact and keeping updated with friends. Two scales measuring activities on other users’ profiles and contact with friends’ profiles were developed and validated. As predicted, some cross-cultural differences were found. Koreans were more likely to use SNS to increase contact but tended to spend less time browsing contacts’ profiles than the Malaysians and Chinese. The intensity of SNS use differed between the countries as well, where Malaysians reported higher intensity than Koreans and Chinese. Consistent with study predictions, Koreans were found with the highest Autonomous-Related self-construal scores. The Autonomous-Related self-construal predicted SNS intensity. The findings suggest that cultural contexts, along with the way the self is construed in different cultures, may encourage different types of SNS usage. The authors discuss study implications and suggest future research directions.
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Lee, Soon Li; Kim, Jung-Ae; Golden, Karen Jennifer; Kim, Jae-Hwi; Park, Miriam Sang-Ah
2016-01-01
Perception of the autonomy and relatedness of the self may be influenced by one's experiences and social expectations within a particular cultural setting. The present research examined the role of culture and the Autonomous-Related self-construal in predicting for different aspects of Social Networking Sites (SNS) usage in three Asian countries, especially focusing on those aspects serving interpersonal goals. Participants in this cross-cultural study included 305 university students from Malaysia (n = 105), South Korea (n = 113), and China (n = 87). The study explored specific social and interpersonal behaviors on SNS, such as browsing the contacts' profiles, checking for updates, and improving contact with SNS contacts, as well as the intensity of SNS use, hypothesizing that those with high intensity of use in the Asian context may be doing so to achieve the social goal of maintaining contact and keeping updated with friends. Two scales measuring activities on other users' profiles and contact with friends' profiles were developed and validated. As predicted, some cross-cultural differences were found. Koreans were more likely to use SNS to increase contact but tended to spend less time browsing contacts' profiles than the Malaysians and Chinese. The intensity of SNS use differed between the countries as well, where Malaysians reported higher intensity than Koreans and Chinese. Consistent with study predictions, Koreans were found with the highest Autonomous-Related self-construal scores. The Autonomous-Related self-construal predicted SNS intensity. The findings suggest that cultural contexts, along with the way the self is construed in different cultures, may encourage different types of SNS usage. The authors discuss study implications and suggest future research directions.
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Lee, Soon Li; Kim, Jung-Ae; Golden, Karen Jennifer; Kim, Jae-Hwi; Park, Miriam Sang-Ah
2016-01-01
Perception of the autonomy and relatedness of the self may be influenced by one's experiences and social expectations within a particular cultural setting. The present research examined the role of culture and the Autonomous-Related self-construal in predicting for different aspects of Social Networking Sites (SNS) usage in three Asian countries, especially focusing on those aspects serving interpersonal goals. Participants in this cross-cultural study included 305 university students from Malaysia (n = 105), South Korea (n = 113), and China (n = 87). The study explored specific social and interpersonal behaviors on SNS, such as browsing the contacts' profiles, checking for updates, and improving contact with SNS contacts, as well as the intensity of SNS use, hypothesizing that those with high intensity of use in the Asian context may be doing so to achieve the social goal of maintaining contact and keeping updated with friends. Two scales measuring activities on other users' profiles and contact with friends' profiles were developed and validated. As predicted, some cross-cultural differences were found. Koreans were more likely to use SNS to increase contact but tended to spend less time browsing contacts' profiles than the Malaysians and Chinese. The intensity of SNS use differed between the countries as well, where Malaysians reported higher intensity than Koreans and Chinese. Consistent with study predictions, Koreans were found with the highest Autonomous-Related self-construal scores. The Autonomous-Related self-construal predicted SNS intensity. The findings suggest that cultural contexts, along with the way the self is construed in different cultures, may encourage different types of SNS usage. The authors discuss study implications and suggest future research directions. PMID:27148100
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Fabrication of SnS thin films by the successive ionic layer adsorption and reaction (SILAR) method
International Nuclear Information System (INIS)
Ghosh, Biswajit; Das, Madhumita; Banerjee, Pushan; Das, Subrata
2008-01-01
Tin sulfide films of 0.20 µm thickness were grown on glass and ITO substrates by the successive ionic layer adsorption and reaction (SILAR) method using SnSO 4 and Na 2 S solution. The as-grown films were well covered and strongly adherent to the substrate. XRD confirmed the deposition of SnS thin films and provided information on the crystallite size and residual strain of the thin films. FESEM revealed almost equal distribution of the particle size well covered on the surface of the substrate. EDX showed that as-grown SnS films were slightly rich in tin component. High absorption in the visible region was evident from UV–Vis transmission spectra. PL studies were carried out with 550 nm photon excitation. To the best of our knowledge, however, no attempt has been made to fabricate a SnS thin film using the SILAR technique
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SNS 2.1K Cold Box Turn-down Studies
International Nuclear Information System (INIS)
F. Casagrande; P.A. Gurd; D.R. Hatfield; M.P. Howell; W.H. Strong; D. Arenius; J. Creel; V. Ganni; P. Knudsen
2006-01-01
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is nearing completion. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 watt cryogenic refrigeration system. The 2.1K cold box consists of four stages of centrifugal compressors with LN2-cooled variable speed electric motors and magnetic bearings. The cryogenic system successfully supported the Linac beam commissioning at both 4.2K and 2.1K and has been fully operational since June 2005. This paper describes the control principles utilized and the experimental results obtained for the SNS cold compressors turn-down capability to about 30% of the design flow, and possible limitation of the frequency dependent power factor of the cold compressor electric motors, which was measured for the first time during commissioning. These results helped to support the operation of the Linac over a very broad and stable cold compressor operating flow range (refrigeration capacity) and pressure. This in turn helped to optimize the cryogenic system operating parameters, minimizing the utilities and improving the system reliability and availability
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International Nuclear Information System (INIS)
Gallmeier, F.X.; Glasgow, D.C.; Jerde, E.A.; Johnson, J.O.; Yugo, J.J.
1999-01-01
The Spallation Neutron Source (SNS) will provide an intense source of low-energy neutrons for experimental use. The low-energy neutrons are produced by the interaction of a high-energy (1.0 GeV) proton beam on a mercury (Hg) target and slowed down in liquid hydrogen or light water moderators. Computer codes and computational techniques are being benchmarked against relevant experimental data to validate and verify the tools being used to predict the performance of the SNS. The LAHET Code System (LCS), which includes LAHET, HTAPE ad HMCNP (a modified version of MCNP version 3b), have been applied to the analysis of experiments that were conducted in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). In the AGS experiments, foils of various materials were placed around a mercury-filled stainless steel cylinder, which was bombarded with protons at 1.6 GeV. Neutrons created in the mercury target, activated the foils. Activities of the relevant isotopes were accurately measured and compared with calculated predictions. Measurements at BNL were provided in part by collaborating scientists from JAERI as part of the AGS Spallation Target Experiment (ASTE) collaboration. To date, calculations have shown good agreement with measurements
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van der Waals epitaxy of SnS film on single crystal graphene buffer layer on amorphous SiO2/Si
Xiang, Yu; Yang, Yunbo; Guo, Fawen; Sun, Xin; Lu, Zonghuan; Mohanty, Dibyajyoti; Bhat, Ishwara; Washington, Morris; Lu, Toh-Ming; Wang, Gwo-Ching
2018-03-01
Conventional hetero-epitaxial films are typically grown on lattice and symmetry matched single crystal substrates. We demonstrated the epitaxial growth of orthorhombic SnS film (∼500 nm thick) on single crystal, monolayer graphene that was transferred on the amorphous SiO2/Si substrate. Using X-ray pole figure analysis we examined the structure, quality and epitaxy relationship of the SnS film grown on the single crystal graphene and compared it with the SnS film grown on commercial polycrystalline graphene. We showed that the SnS films grown on both single crystal and polycrystalline graphene have two sets of orientation domains. However, the crystallinity and grain size of the SnS film improve when grown on the single crystal graphene. Reflection high-energy electron diffraction measurements show that the near surface texture has more phases as compared with that of the entire film. The surface texture of a film will influence the growth and quality of film grown on top of it as well as the interface formed. Our result offers an alternative approach to grow a hetero-epitaxial film on an amorphous substrate through a single crystal graphene buffer layer. This strategy of growing high quality epitaxial thin film has potential applications in optoelectronics.
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An automatic sample changer for use on the SNS
International Nuclear Information System (INIS)
1982-10-01
A design for an Automatic Room Temperature Sample Changer suitable for any completely contained sample, gas, liquid or solid, has been produced. Samples can be moved in any sequence into the neutron beam. The design was evolved primarily to suit SNS instruments. A prototype was constructed specifically for the LAD spectrometer having ten sample positions. The accuracy of the sample positioning was determined. (author)
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Electron-cloud simulation results for the PSR and SNS
International Nuclear Information System (INIS)
Pivi, M.; Furman, M.A.
2002-01-01
We present recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos. In particular, a complete refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has been included in the simulation code
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A low-temperature sample orienting device for single crystal spectroscopy at the SNS
Energy Technology Data Exchange (ETDEWEB)
Sherline, T E; Solomon, L; Roberts, C K II; Bruce, D; Gaulin, B; Granroth, G E, E-mail: sherlinete@ornl.gov
2010-11-01
A low temperature sample orientation device providing three axes of rotation has been successfully built and is in testing for use on several spectrometers at the spallation neutron source (SNS). Sample rotation about the vertical ({omega}) axis of nearly 360 deg. and out of plane tilts ({phi} and v) of from -3.4 deg. to 4.4 deg. and from -2.8 deg. to 3.5 deg., respectively, are possible. An off-the-shelf closed cycle refrigerator (CCR) is mounted on a room temperature sealed rotary flange providing {omega} rotations of the sample. Out-of-plane tilts are made possible by piezoelectric actuated angular positioning devices mounted on the low temperature head of the CCR. Novel encoding devices based on magnetoresistive sensors have been developed to measure the tilt stage angles. This combination facilitates single crystal investigations from room temperature to 3.1 K. Commissioning experiments of the rotating CCR for both powder and single crystal samples have been performed on the ARCS spectrometer at the SNS. For the powder sample this device was used to continuously rotate the sample and thus average out any partial orientation of the powder. The powder rings observed in S(Q) are presented. For the single crystal sample, the rotation was used to probe different regions of momentum transfer (Q-space). Laue patterns obtained from a single crystal sample at two rotation angles are presented.
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Bakhshayeshi, A.; Taghavi Mendi, R.; Majidiyan Sarmazdeh, M.
2018-02-01
Recently, a cubic structure of polymorphic SnS2 has been synthesized experimentally, which is stable at room temperature. In this paper, we calculated some structural, electronic and optical properties of the cubic SnS2 structure based on the full potential-linearized augmented plane waves method. We also studied the effect of hydrostatic pressure on the physical properties of the cubic SnS2 structure. Structural results show that the compressibility of the cubic SnS2 phase is greater than its trigonal phase and the compressibility decreases with increasing pressure. Investigations of the electronic properties indicate that pressure changes the density of states and the energy band gap increases with increasing pressure. The variation of energy band gap versus pressure is almost linear. We concluded that cubic SnS2 is a semiconductor with an indirect energy band gap, like its trigonal phase. The optical calculations revealed that the dielectric constant decreases with increasing pressure, and the width of the forbidden energy interval increases for electromagnetic wave propagation. Moreover, plasmonic energy and refractive index are changed with increasing pressure.
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FRIB Cryogenic Distribution System and Status
Energy Technology Data Exchange (ETDEWEB)
Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Laverdure, Nathaniel A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Yang, Shuo [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Nellis, Timothy [Michigan State Univ., East Lansing, MI (United States); Jones, S. [Michigan State Univ., East Lansing, MI (United States); Casagrande, Fabio [Michigan State Univ., East Lansing, MI (United States)
2015-12-01
The MSU-FRIB cryogenic distribution system supports the 2 K primary, 4 K primary, and 35 - 55 K shield operation of more than 70 loads in the accelerator and the experimental areas. It is based on JLab and SNS experience with bayonet-type disconnects between the loads and the distribution system for phased commissioning and maintenance. The linac transfer line, which features three separate transfer line segments for additional independence during phased commissioning at 4 K and 2 K, connects the folded arrangement of 49 cryomodules and 4 superconducting dipole magnets and a fourth transfer line supports the separator area cryo loads. The pressure reliefs for the transfer line process lines, located in the refrigeration room outside the tunnel/accelerator area, are piped to be vented outdoors. The transfer line designs integrate supply and return flow paths into a combined vacuum space. The main linac distribution segments are produced in a small number of standard configurations; a prototype of one such configuration has been fabricated at Jefferson Lab and has been installed at MSU to support testing of a prototype FRIB cryomodule.
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International Nuclear Information System (INIS)
Bashkirov, S.A.; Gremenok, V.F.; Ivanov, V.A.; Shevtsova, V.V.; Gladyshev, P.P.
2015-01-01
Tin monosulfide SnS raises an interest as a promising material for photovoltaics. The influence of the substrate material on the microstructure and optical properties of SnS thin films with [111] texture obtained by hot wall vacuum deposition on glass, molybdenum and indium tin oxide substrates is reported. The lattice parameters for layers grown on different substrates were determined by X-ray diffraction and their deviations from the data reported in the literature for single α-SnS crystals were discussed. The change in the degree of preferred orientation of the films depending on the substrate material is observed. The direct nature of the optical transitions with the optical band gap of 1.15 ± 0.01 eV is reported. - Highlights: • SnS thin films were hot wall deposited on glass, molybdenum and indium tin oxide. • Physical properties of the films were studied with respect to the substrate type. • The SnS lattice parameter deviations were observed and the explanation was given. • The direct optical transitions with the band gap of 1.15 ± 0.01 eV were observed
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Improving cycle stability of SnS anode for sodium-ion batteries by limiting Sn agglomeration
Wang, Wenhui; Shi, Liang; Lan, Danni; Li, Quan
2018-02-01
Flower-like SnS nanostructures are obtained by a simple solvothermal method for anode applications in Na-ion batteries. We show experimental evidence of progressive Sn agglomeration and crystalline Na2S enrichment at the end of de-sodiation process of the SnS electrode, both of which contribute to the capacity decay of the electrode upon repeated cycles. By replacing the commonly adopted acetylene black conductive additive with multi-wall carbon nanotubes (MWCNT), the cycle stability of the SnS electrode is largely improved, which correlates well with the observed suppression of both Sn agglomeration and Na2S enrichment at the end of de-sodiation cycle. A full cell is assembled with the SnS/MWCNT anode and the P2-Na2/3Ni1/3Mn1/2Ti1/6O2 cathode. An initial energy density of 262 Wh/kg (normalized to the total mass of cathode and anode) is demonstrated for the full cell, which retains 71% of the first discharge capacity after 40 cycles.
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Energy Technology Data Exchange (ETDEWEB)
Robles, Víctor, E-mail: victor.robles@ciemat.es; Trigo, Juan Francisco; Guillén, Cecilia; Herrero, José
2015-05-01
Tin sulfide thin films were prepared by co-evaporation on soda-lime glass substrates, for use as absorber layers. The synthesis was carried out at 350 °C substrate temperature and varying the growth rate in the 2-6 Å/s range, adjusting the deposition time in order to obtain thicknesses in the 700-1500 nm range. After evaporation, the samples were heated at 400 °C and 500 °C under various atmospheres. The evolution of the morphological, structural and optical properties has been analyzed as a function of the thickness and deposition rate, before and after annealing. For the samples grown at the lowest rate, SnS and Sn{sub 2}S{sub 3} phase mixing has been observed by X-ray diffraction. Samples with reduced thickness preferably crystallize in the SnS phase, whereas thicker layers become richer in the Sn{sub 2}S{sub 3} phase. The sulfur treatment of samples prepared at the lowest rate results in the formation of SnS{sub 2} phase. Otherwise, the samples obtained at the highest rates show single-phase SnS after heating at 400 °C in sulfur atmosphere, with gap energy values around 1.24 eV. - Highlights: • Tin sulfide thin films were deposited by co-evaporation at different growth rates. • The influence of the growth rate and post-annealing at different conditions was studied. • The SnS phase was obtained by optimizing the growth rate and the annealing process. • The SnS phase presented properties for use as absorber layer.
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International Nuclear Information System (INIS)
Kim, Sang-Ho; Campisi, Isidoro E.
2007-01-01
The baseline Spallation Neutron Source (SNS) accelerator will provide a 1 GeV, 1.4 MW proton beam to a mercury target for the production of neutrons. The main acceleration for the H- beam is provided by 81 superconducting cavities installed in 23 cryomodules operating at 805 MHz. The design of the superconducting linac includes a 2.1 K, 2.5 kW cryogenic plant to maintain the cavities below the helium lambda point for efficient operation at high accelerating gradients. In this paper operating conditions are analyzed rather than the design ones, which still guarantees a high gradient operation without any temperature constraint. From the analysis it appears that the SNS superconducting linac can be operated at temperatures higher than 2.1 K, a fact resulting from both the pulsed nature of the superconducting cavities, the specific configuration of the existing cryogenic plant and the operating frequency. General conditions are also given regarding the operation of pulsed superconducting cavities resonating at different frequencies
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International Nuclear Information System (INIS)
Johnson, J.O.
2000-01-01
The Department of Energy (DOE) has given the Spallation Neutron Source (SNS) project approval to begin Title I design of the proposed facility to be built at Oak Ridge National Laboratory (ORNL) and construction is scheduled to commence in FY01 . The SNS initially will consist of an accelerator system capable of delivering an ∼0.5 microsecond pulse of 1 GeV protons, at a 60 Hz frequency, with 1 MW of beam power, into a single target station. The SNS will eventually be upgraded to a 2 MW facility with two target stations (a 60 Hz station and a 10 Hz station). The radiation transport analysis, which includes the neutronic, shielding, activation, and safety analyses, is critical to the design of an intense high-energy accelerator facility like the proposed SNS, and the Monte Carlo method is the cornerstone of the radiation transport analyses
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International Nuclear Information System (INIS)
Kim, Sang-Ho; Campisi, Isidoro E.
2007-01-01
In order to address the optimization in a pulsed operation, a systematic computational analysis has been made in comparison with operational experiences in superconducting radio-frequency (SRF) cavities at the Spallation Neutron Source (SNS). From the analysis it appears that the SNS SRF cavities can be operated at temperatures higher than 2.1 K, a fact resulting from both the pulsed nature of the superconducting cavities, the specific configuration of the existing cryogenic plant and the operating frequency
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International Nuclear Information System (INIS)
Li, Shuankui; Zuo, Shiyong; Wu, Zhiguo; Liu, Ying; Zhuo, Renfu; Feng, Juanjuan; Yan, De; Wang, Jun; Yan, Pengxun
2014-01-01
A hybrid of multi-walled carbon nanotubes (MWCNTs) anchored with SnS nanosheets is synthesized through a simple solvothermal method for the first time. Interestingly, SnS can be controllably deposited onto the MWCNTs backbone in the shape of nanosheets or nanoparticles to form two types of SnS/MWCNTs hybrids, SnS NSs/MWCNTs and SnS NPs/MWCNTs. When evaluated as an anode material for lithium-ion batteries, the hybrids exhibit higher lithium storage capacities and better cycling performance compared to pure SnS. It is found that the SnS NSs/MWCNTs hybrid exhibits a large reversible capacity of 620mAhg −1 at a current of 100mAg −1 as an anode material for lithium-ion batteries, which is better than SnS NPs/MWCNTs. The improved performance may be attributed to the ultrathin nanosheet subunits possess short distance for Li + ions diffusion and large electrode-electrolyte contact area for high Li + ions flux across the interface. It is believed that the structural design of electrodes demonstrated in this work will have important implications on the fabrication of high-performance electrode materials for lithium-ion batteries
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International Nuclear Information System (INIS)
Wang Meng; Zhou Yang; Chen Dongzhong; Duan Junfei
2016-01-01
In this work, azobenzene mesogen-containing tin thiolates have been synthesized, which possess ordered lamellar structures persistent to higher temperature and serve as liquid crystalline precursors. Based on the preorganized tin thiolate precursors, SnS nanocrystals encapsulated with in-situ N-doped carbon layer have been achieved through a simple solventless pyrolysis process with the azobenzene mesogenic thiolate precursor served as Sn, S, N, and C sources simultaneously. Thus prepared nanocomposite materials as anode of lithium ion batteries present a large specific capacity of 604.6 mAh·g −1 at a current density of 100 mA·g −1 , keeping a high capacity retention up to 96% after 80 cycles, and display high rate capability due to the synergistic effect of well-dispersed SnS nanocrystals and N-doped carbon layer. Such encouraging results shed a light on the controlled preparation of advanced nanocomposites based on liquid crystalline metallomesogen precursors and may boost their novel intriguing applications. (special topic)
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805 MHz β = 0.47 Elliptical Accelerating Structure R and D. Final Report
International Nuclear Information System (INIS)
Bricker, S.; Compton, C.; Hartung, W.; Johnson, M.; Marti, F.; Popierlarski, J.; York, R.C.
2008-01-01
A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q 0 ) were between 7 · 10 9 and 1.4 · 10 10 at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.
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Goh Say Leng; Suddin Lada; Mohd Zulkifli Muhammad; Ag Asri Hj Ag Ibrahim; Tamrin Amboala
2011-01-01
The objective of the paper is to explore the factors that encourage students to adopt social network sites (SNS) in Malaysia and to use the study’s findings to develop guidelines for SNS providers on how to maximize the rate of adoption. A conceptual model of Technology Acceptance Model (TAM), Theory of Planned Behaviour (TPB) and intrinsic motivation is proposed and empirically tested in the context of SNS usage. Structural Equation modelling was used on the survey data from 283 university s...
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Fang, CM; deGroot, RA; Wiegers, GA; Haas, C
1996-01-01
In order to understand the electronic structure of the incommensurate misfit layer compound (SnS)(1.20)TiS2 we carried out an ab initio band structure calculation in the supercell approximation. The band structure is compared with that of the components 1T-TiS2 and hypothetical SnS with a similar
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Fang, C.M.; Groot, R.A. de; Wiegers, G.A.; Haas, C.
1996-01-01
In order to understand the electronic structure of the incommensurate misfit layer compound (SnS)1.20TiS2 we carried out an ab initio band structure calculation in the supercell approximation. The band structure is compared with that of the components 1T-TiS2 and hypothetical SnS with a similar
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Higher-order-mode absorbers for energy recovery linac cryomodules at Brookhaven National Laboratory
International Nuclear Information System (INIS)
Hahn, H.; Ben-Zvi, I.; Calaga, R.; Hammons, L.; Johnson, E.C.; Kewisch, J.; Litvinenko, V.N.; Xu, W.
2010-01-01
Several future accelerator projects at Brookhaven for the Relativistic Heavy Ion Collider (RHIC) are based on energy recovery linacs (ERLs) with high-charge high-current electron beams. Their stable operation mandates effective higher-order-mode (HOM) damping. The development of HOM dampers for these projects is pursued actively at this laboratory. Strong HOM damping was experimentally demonstrated both at room and at superconducting (SC) temperatures in a prototype research and development (R and D) five-cell niobium superconducting rf (SRF) cavity with ferrite dampers. Two room-temperature mock-up five-cell copper cavities were used to study various damper configurations with emphasis on capacitive antenna dampers. An innovative type of ferrite damper over a ceramic break for an R and D SRF electron gun also was developed. For future SRF linacs longer cryomodules comprised of multiple superconducting cavities with reasonably short intercavity transitions are planned. In such a configuration, the dampers, located closer to the cavities, will be at cryogenic temperatures; this will impose additional constraints and complications. This paper presents the results of simulations and measurements of several damper configurations.
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Higher-order-mode absorbers for energy recovery linac cryomodules at Brookhaven National Laboratory
Hahn, H.; Ben-Zvi, I.; Calaga, R.; Hammons, L.; Johnson, E. C.; Kewisch, J.; Litvinenko, V. N.; Xu, Wencan
2010-12-01
Several future accelerator projects at Brookhaven for the Relativistic Heavy Ion Collider (RHIC) are based on energy recovery linacs (ERLs) with high-charge high-current electron beams. Their stable operation mandates effective higher-order-mode (HOM) damping. The development of HOM dampers for these projects is pursued actively at this laboratory. Strong HOM damping was experimentally demonstrated both at room and at superconducting (SC) temperatures in a prototype research and development (R&D) five-cell niobium superconducting rf (SRF) cavity with ferrite dampers. Two room-temperature mock-up five-cell copper cavities were used to study various damper configurations with emphasis on capacitive antenna dampers. An innovative type of ferrite damper over a ceramic break for an R&D SRF electron gun also was developed. For future SRF linacs longer cryomodules comprised of multiple superconducting cavities with reasonably short intercavity transitions are planned. In such a configuration, the dampers, located closer to the cavities, will be at cryogenic temperatures; this will impose additional constraints and complications. This paper presents the results of simulations and measurements of several damper configurations.
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Higher-order-mode absorbers for energy recovery linac cryomodules at Brookhaven National Laboratory
Directory of Open Access Journals (Sweden)
H. Hahn
2010-12-01
Full Text Available Several future accelerator projects at Brookhaven for the Relativistic Heavy Ion Collider (RHIC are based on energy recovery linacs (ERLs with high-charge high-current electron beams. Their stable operation mandates effective higher-order-mode (HOM damping. The development of HOM dampers for these projects is pursued actively at this laboratory. Strong HOM damping was experimentally demonstrated both at room and at superconducting (SC temperatures in a prototype research and development (R&D five-cell niobium superconducting rf (SRF cavity with ferrite dampers. Two room-temperature mock-up five-cell copper cavities were used to study various damper configurations with emphasis on capacitive antenna dampers. An innovative type of ferrite damper over a ceramic break for an R&D SRF electron gun also was developed. For future SRF linacs longer cryomodules comprised of multiple superconducting cavities with reasonably short intercavity transitions are planned. In such a configuration, the dampers, located closer to the cavities, will be at cryogenic temperatures; this will impose additional constraints and complications. This paper presents the results of simulations and measurements of several damper configurations.
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Tunneling Diode Based on WSe2 /SnS2 Heterostructure Incorporating High Detectivity and Responsivity.
Zhou, Xing; Hu, Xiaozong; Zhou, Shasha; Song, Hongyue; Zhang, Qi; Pi, Lejing; Li, Liang; Li, Huiqiao; Lü, Jingtao; Zhai, Tianyou
2018-02-01
van der Waals (vdW) heterostructures based on atomically thin 2D materials have led to a new era in next-generation optoelectronics due to their tailored energy band alignments and ultrathin morphological features, especially in photodetectors. However, these photodetectors often show an inevitable compromise between photodetectivity and photoresponsivity with one high and the other low. Herein, a highly sensitive WSe 2 /SnS 2 photodiode is constructed on BN thin film by exfoliating each material and manually stacking them. The WSe 2 /SnS 2 vdW heterostructure shows ultralow dark currents resulting from the depletion region at the junction and high direct tunneling current when illuminated, which is confirmed by the energy band structures and electrical characteristics fitted with direct tunneling. Thus, the distinctive WSe 2 /SnS 2 vdW heterostructure exhibits both ultrahigh photodetectivity of 1.29 × 10 13 Jones (I ph /I dark ratio of ≈10 6 ) and photoresponsivity of 244 A W -1 at a reverse bias under the illumination of 550 nm light (3.77 mW cm -2 ). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Single-Crystal Growth of Cl-Doped n-Type SnS Using SnCl2 Self-Flux.
Iguchi, Yuki; Inoue, Kazutoshi; Sugiyama, Taiki; Yanagi, Hiroshi
2018-06-05
SnS is a promising photovoltaic semiconductor owing to its suitable band gap energy and high optical absorption coefficient for highly efficient thin film solar cells. The most significant carnage is demonstration of n-type SnS. In this study, Cl-doped n-type single crystals were grown using SnCl 2 self-flux method. The obtained crystal was lamellar, with length and width of a few millimeters and thickness ranging between 28 and 39 μm. X-ray diffraction measurements revealed the single crystals had an orthorhombic unit cell. Since the ionic radii of S 2- and Cl - are similar, Cl doping did not result in substantial change in lattice parameter. All the elements were homogeneously distributed on a cleaved surface; the Sn/(S + Cl) ratio was 1.00. The crystal was an n-type degenerate semiconductor with a carrier concentration of ∼3 × 10 17 cm -3 . Hall mobility at 300 K was 252 cm 2 V -1 s -1 and reached 363 cm 2 V -1 s -1 at 142 K.
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BEAM-LOSS DRIVEN DESIGN OPTIMIZATION FOR THE SPALLATION NEUTRON SOURCE (SNS) RING.
Energy Technology Data Exchange (ETDEWEB)
WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; CAMERON,P.; DANBY,G.; GARDNER,C.J.; JACKSON,J.; LEE,Y.Y.; LUDEWIG,H.; MALITSKY,N.; RAPARIA,D.; TSOUPAS,N.; WENG,W.T.; ZHANG,S.Y.
1999-03-29
This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).
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Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring
International Nuclear Information System (INIS)
Wei, J.
1999-01-01
This paper summarizes three-state design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.)
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DESIGN OF AN IMPROVED ION CHAMBER FOR THE SNS.
Energy Technology Data Exchange (ETDEWEB)
WITKOVER,R.L.; GASSNER,D.
2002-05-06
Ion chambers are in common use as beam loss monitors at many accelerators. A unit designed and used at FNAL and later at BNL was proposed for the SNS. Concerns about the ion collection times and low collection efficiency at high loss rates led to improvements to this unit and the design of an alternate chamber with better characteristics. Prototypes have been tested with pulsed beams. The design and test results for both detectors will be presented.
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Gao, Wei; Li, Yongtao; Guo, Jianhua; Ni, Muxun; Liao, Ming; Mo, Haojie; Li, Jingbo
2018-05-10
Here we report ultrathin SnS1-xSex alloyed nanosheets synthesized via a narrow-gap physical vapour deposition approach. The SnS1-xSex alloy presents a uniform quadrangle shape with a lateral size of 5-80 μm and a thickness of several nanometers. Clear orthorhombic symmetries and unique in-plane anisotropic properties of the 2D alloyed nanosheets were found with the help of X-ray diffraction, high resolution transmission electron microscopy and polarized Raman spectroscopy. Moreover, 2D alloyed field-effect transistors were fabricated, exhibiting a unipolar p-type semiconductor behavior. This study also provided a lesson that the thickness of the alloyed channels played the major role in the current on/off ratio, and the high ratio of 2.10 × 102 measured from a large ultrathin SnS1-xSex device was two orders of magnitude larger than that of previously reported SnS, SnSe nanosheet based transistors because of the capacitance shielding effect. Obviously enhanced Raman peaks were also found in the thinner nanosheets. Furthermore, the ultrathin SnS0.5Se0.5 based photodetector showed a highest responsivity of 1.69 A W-1 and a short response time of 40 ms under illumination of a 532 nm laser from 405 to 808 nm. Simultaneously, the corresponding highest external quantum efficiency of 392% and detectivity of 3.96 × 104 Jones were also achieved. Hopefully, the narrow-gap synthesis technique provides us with an improved strategy to obtain large ultrathin 2D nanosheets which may tend to grow into thicker ones for stronger interlayer van der Waals forces, and the enhanced physical and (opto)electrical performances in the obtained ultrathin SnS1-xSex alloyed nanosheets prove their great potential in the future applications for versatile devices.
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International Nuclear Information System (INIS)
Avellaneda, David; Delgado, Guadalupe; Nair, M.T.S.; Nair, P.K.
2007-01-01
Chemically deposited SnS thin films possess p-type electrical conductivity. We report a photovoltaic structure: SnO 2 :F-CdS-SnS-(CuS)-silver print, with V oc > 300 mV and J sc up to 5 mA/cm 2 under 850 W/m 2 tungsten halogen illumination. Here, SnO 2 :F is a commercial spray-CVD (Pilkington TEC-8) coating, and the rest deposited from different chemical baths: CdS (80 nm) at 333 K, SnS (450 nm) and CuS (80 nm) at 293-303 K. The structure may be heated in nitrogen at 573 K, before applying the silver print. The photovoltaic behavior of the structure varies with heating: V oc ∼ 400 mV and J sc 2 , when heated at 423 K in air, but V oc decreases and J sc increases when heated at higher temperatures. These photovoltaic structures have been found to be stable over a period extending over one year by now. The overall cost of materials, simplicity of the deposition process, and possibility of easily varying the parameters to improve the cell characteristics inspire further work. Here we report two different baths for the deposition of SnS thin films of about 500 nm by chemical deposition. There is a considerable difference in the nature of growth, crystalline structure and chemical stability of these films under air-heating at 623-823 K or while heating SnS-CuS layers, evidenced in XRF and grazing incidence angle XRD studies. Heating of SnS-CuS films results in the formation of SnS-Cu x SnS y . 'All-chemically deposited photovoltaic structures' involving these materials are presented
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805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D
Energy Technology Data Exchange (ETDEWEB)
S. Bricker; C. Compton; W. Hartung; M. Johnson; F. Marti; J. Popierlarski; R. C. York; et al
2008-09-22
A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.
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Energy Technology Data Exchange (ETDEWEB)
Sousa, M.G., E-mail: martasousa@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Cunha, A.F. da, E-mail: antonio.cunha@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Fernandes, P.A., E-mail: pafernandes@ua.pt [AIN, I3N and Departamento de Física, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Departamento de Física, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto (Portugal)
2014-04-01
then correlated with the annealing temperature. Scanning electron microscopy studies revealed that the SnS films exhibit small grain structure and the film surface is rough. Optical measurements were performed, from which the band gap energies were estimated. These studies show that the direct absorption transitions of SnS are at 1.68 eV and 1.41 eV for annealing in graphite box with and without elemental sulphur evaporation, respectively. For the indirect transition the values varied from 1.49 eV to 1.37 eV. The results of this work show that the third approach is better suited to produce single phase SnS films. However, a finer tunning of the duration of the high temperature plateau of the annealing profile is required in order to eliminate the β-Sn top layer.
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Mechanical design of the SNS MEBT
International Nuclear Information System (INIS)
Oshatz, D.; DeMello, A.; Doolittle, L.; Luft, P.; Staples, J.; Zachoszcz, A.
2001-01-01
The Lawrence Berkeley National Laboratory (LBNL) is presently designing and building the 2.5 MeV front end for the Spallation Neutron Source (SNS). The front end includes a medium-energy beam transport (MEBT) that carries the 2.5 MeV, 38 mA peak current, H - beam from the radio frequency quadrupole (RFQ) to the drift tube linac (DTL) through a series of 14 electromagnetic quadrupoles, four rebuncher cavities, and a fast traveling wave chopping system. The beamline contains numerous diagnostic devices, including stripline beam position and phase monitors (BPM), toroid beam current monitors (BCM), and beam profile monitors. Components are mounted on three rafts that are separately supported and aligned. The large number of beam transport and diagnostic components in the 3.6 meter-long beamline necessitates an unusually compact mechanical design
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Gao, Peng; Wang, Liping; Zhang, Yu-Yang; Huang, Yuan; Liao, Lei; Sutter, Peter; Liu, Kaihui; Yu, Dapeng; Wang, En-Ge
2016-09-14
In the rechargeable lithium ion batteries, the rate capability and energy efficiency are largely governed by the lithium ion transport dynamics and phase transition pathways in electrodes. Real-time and atomic-scale tracking of fully reversible lithium insertion and extraction processes in electrodes, which would ultimately lead to mechanistic understanding of how the electrodes function and why they fail, is highly desirable but very challenging. Here, we track lithium insertion and extraction in the van der Waals interactions dominated SnS2 by in situ high-resolution TEM method. We find that the lithium insertion occurs via a fast two-phase reaction to form expanded and defective LiSnS2, while the lithium extraction initially involves heterogeneous nucleation of intermediate superstructure Li0.5SnS2 domains with a 1-4 nm size. Density functional theory calculations indicate that the Li0.5SnS2 is kinetically favored and structurally stable. The asymmetric reaction pathways may supply enlightening insights into the mechanistic understanding of the underlying electrochemistry in the layered electrode materials and also suggest possible alternatives to the accepted explanation of the origins of voltage hysteresis in the intercalation electrode materials.
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Direct fabrication of a W-C SNS Josephson junction using focused-ion-beam chemical vapour deposition
International Nuclear Information System (INIS)
Dai, Jun; Kometani, Reo; Ishihara, Sunao; Warisawa, Shin’ichi; Onomitsu, Koji; Krockenberger, Yoshiharu; Yamaguchi, Hiroshi
2014-01-01
A tungsten-carbide (W-C) superconductor/normal metal/superconductor (SNS) Josephson junction has been fabricated using focused-ion-beam chemical vapour deposition (FIB-CVD). Under certain process conditions, the component ratio has been tuned from W: C: Ga = 26%: 66%: 8% in the superconducting wires to W: C: Ga = 14%: 79%: 7% in the metallic junction. The critical current density at 2.5 K in the SNS Josephson junction is 1/3 of that in W-C superconducting nanowire. Also, a Fraunhofer-like oscillation of critical current in the junction with four periods is observed. FIB-CVD opens avenues for novel functional superconducting nanodevices. (paper)
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Laurent, Heidemarie K.; Ablow, Jennifer C.; Measelle, Jeffrey
2012-01-01
This study investigated continuity and stability of hypothalamic-pituitary-adrenal (HPA) and sympathetic nervous system (SNS) response measures in mother-infant dyads across 2 different types of social stress sessions. Synchrony of response trajectories across systems (SNS-HPA coordination) and partners (mother-infant attunement) was addressed, as…
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DOUBLE-WALL COLLIMATOR DESIGN OF THE SNS PROJECT
International Nuclear Information System (INIS)
SIMOS, N.; LUDEWIG, H.; CATALAN-LASHERAS, N.; CRIVELLO, S.
2001-01-01
The collimator absorber array of the Spallation Neutron Source (SNS) project is responsible for stopping the 1.0 GeV protons that are in the halo of the beam. It is estimated that 0.1% of the 2 MW beam will be intercepted by the adopted collimating scheme implemented at various sections of the beam transport and accumulation. This paper summarizes the conceptual design of the collimator absorber as well as the supporting detailed analysis that were performed and guided the design process. Key requirement in the design process is the need for the collimator beam tube to minimize beam impedance while closely following its beta function. Due to lack of available experimental data, the long-term behavior of irradiated materials in an environment where they interface with coolant flow becomes an issue. Uncertainties in the long-term behavior prompted a special double-wall design that will enable not only beam halo interception but also the efficient transfer of deposited energy both under normal and off-normal conditions to the coolant flow. The thermo-mechanical response of the double wall beam tube and of a particle bed surrounding it are discussed in detail in the paper
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On the modification to the SNS extracted proton beam to allow for a transmission target
International Nuclear Information System (INIS)
Reading, D.H.
1979-07-01
The present SNS proton beam line consists of a series of triplets of quadrupoles with an achromatic bend such that the protons are taken from the accelerator ring into Hall 3, down its centre line onto the target. The modification described here has been prompted by the demands of a proposed negative pion bio-medical beam line, and the adaption replaces the last three triplets QT12, QT13 and QT14 (Quadrupoles Q41 to Q49 incl.). It begins at an achromatic waist in the original design, and by the use of three triplets of greater aperture produces a further small waist for a target station before focussing the 'object' produced by this transmission target onto the SNS target. (UK)
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DEFF Research Database (Denmark)
Kasper, Christina; Pickering, Darryl S; Mirza, Osman
2006-01-01
domains has been observed. (S)-NS1209 adopts a novel binding mode, including hydrogen bonding to Tyr450 and Gly451 of D1. Parts of (S)-NS1209 occupy new areas of the GluR2 ligand-binding cleft, and bind near residues that are not conserved among receptor subtypes. The affinities of (RS)-NS1209 at the Glu....... The thermodynamics of binding of the antagonists (S)-NS1209, DNQX and (S)-ATPO to the GluR2 ligand-binding core have been determined by displacement isothermal titration calorimetry. The displacement of (S)-glutamate by all antagonists was shown to be driven by enthalpy....
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Evaluation of SNS Beamline Shielding Configurations using MCNPX Accelerated by ADVANTG
International Nuclear Information System (INIS)
Risner, Joel M; Johnson, Seth R.; Remec, Igor; Bekar, Kursat B.
2015-01-01
Shielding analyses for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory pose significant computational challenges, including highly anisotropic high-energy sources, a combination of deep penetration shielding and an unshielded beamline, and a desire to obtain well-converged nearly global solutions for mapping of predicted radiation fields. The majority of these analyses have been performed using MCNPX with manually generated variance reduction parameters (source biasing and cell-based splitting and Russian roulette) that were largely based on the analyst's insight into the problem specifics. Development of the variance reduction parameters required extensive analyst time, and was often tailored to specific portions of the model phase space. We previously applied a developmental version of the ADVANTG code to an SNS beamline study to perform a hybrid deterministic/Monte Carlo analysis and showed that we could obtain nearly global Monte Carlo solutions with essentially uniform relative errors for mesh tallies that cover extensive portions of the model with typical voxel spacing of a few centimeters. The use of weight window maps and consistent biased sources produced using the FW-CADIS methodology in ADVANTG allowed us to obtain these solutions using substantially less computer time than the previous cell-based splitting approach. While those results were promising, the process of using the developmental version of ADVANTG was somewhat laborious, requiring user-developed Python scripts to drive much of the analysis sequence. In addition, limitations imposed by the size of weight-window files in MCNPX necessitated the use of relatively coarse spatial and energy discretization for the deterministic Denovo calculations that we used to generate the variance reduction parameters. We recently applied the production version of ADVANTG to this beamline analysis, which substantially streamlined the analysis process. We also tested importance function
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International Nuclear Information System (INIS)
Johnson, Jeffrey O.; Gallmeier, Franz X.; Popova, Irina
2002-01-01
Determining the bulk shielding requirements for accelerator environments is generally an easy task compared to analyzing the radiation transport through the complex shield configurations and penetrations typically associated with the detailed Title II design efforts of a facility. Shielding calculations for penetrations in the SNS accelerator environment are presented based on hybrid Monte Carlo and discrete ordinates particle transport methods. This methodology relies on coupling tools that map boundary surface leakage information from the Monte Carlo calculations to boundary sources for one-, two-, and three-dimensional discrete ordinates calculations. The paper will briefly introduce the coupling tools for coupling MCNPX to the one-, two-, and three-dimensional discrete ordinates codes in the DOORS code suite. The paper will briefly present typical applications of these tools in the design of complex shield configurations and penetrations in the SNS proton beam transport system
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Programming PLCS under EPICS at the SNS Project : Further Experiences in Collaboration
International Nuclear Information System (INIS)
P. A. Gurd; W. H. Strong; J. D. Creel
2003-01-01
The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Tennessee by a partnership of six national laboratories. The control system components for the SNS were produced by personnel at the collaborating laboratories, by vendors of the equipment, and by commercial contractors. A number of different approaches were used to provide the programming for both the programmable logic controllers (PLCs) and the input-output controllers (IOCs) which were all based on the Experimental Physics and Industrial Control System (EPICS). For conventional facilities, both the PLCs and the IOCs were programmed under a commercial contract. The PLCs for the high power radio frequency system (HPRF) were programmed by the vendors of the equipment, while the IOCs were programmed by the collaborating laboratory. Finally, while the IOCs for the cryogenic systems were programmed at Oak Ridge, three different approaches were used to produce the PLC programming: some were programmed at Oak Ridge, some at TJNAF, and some at vendor sites. This paper discusses the status of the PLCs in the control system and the integration challenges encountered in the various approaches
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Optical Tooling and its Uses at the Spallation Neutron Source (SNS)
Helus, Scott; Error, Joseph; Fazekas, Julius; Maines, James
2005-01-01
Optical tooling has been a mainstay of the accelerator alignment community for decades. Even now in the age of electronic survey equipment, optical tooling remains a viable alternative, and at times the only alternative. At SNS, we combine traditional optical tooling alignment methods, instrumentation, and techniques, with the more modern electronic techniques. This paper deals with the integration of optical tooling into the electronic survey world.
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THE METHODS OF PRODUCING AND ANALYZING POLARIZED NEUTRON BEAMS FOR HYSPEC AT THE SNS
International Nuclear Information System (INIS)
SHAPIRO, S.M.; PASSELL, L.; ZALIZNYAK, A.; GHOSH, V.J.; LEONHARDT, W.L.; HAGEN, M.E.
2005-01-01
The Hybrid Spectrometer (HYSPEC), under construction at the SNS on beam line 14B, is the only inelastic scattering instrument designed to enable polarization of the incident and the scattered neutron beams. A Heusler monochromator will replace the graphite crystal for producing polarized neutrons. In the scattered beam it is planned to use a collimator--multi-channel supermirror bender array to analyze the polarization of the scattered beam over the final energy range from 5-20 meV. Other methods of polarization analysis under consideration such as transmission filters using He 3 , Sm, and polarized protons are considered. Their performance is estimated and a comparison of the various methods of polarization is made
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CONSTRUCTION AND POWER TEST OF THE EXTRACTION KICKER MAGNET FOR SNS ACCUMULATOR RING
International Nuclear Information System (INIS)
PAI, C.; HAHN, H.; HSEUH, H.; LEE, Y.; MENG, W.; MI, J.; SANDBERG, J.; TODD, R.
2005-01-01
Two extraction kicker magnet assemblies that contain seven individual pulsed magnet modules each will kick the proton beam vertically out of the SNS accumulator ring into the aperture of the extraction Lambertson septum magnet. The proton beam then travels to the 1.4 MW SNS target assembly. The 14 kicker magnets and major components of the kicker assembly have been fabricated in BNL. The inner surfaces of the kicker magnets were coated with TiN to reduce the secondary electron yield. All 14 PFN power supplies have been built, tested and delivered to OWL. Before final installation, a partial assembly of the kicker system with three kicker magnets was assembled to test the functions of each critical component in the system. In this paper we report the progress of the construction of the kicker components, the TIN coating of the magnets, the installation procedure of the magnets and the full power test of the kicker with the PFN power supply
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Directory of Open Access Journals (Sweden)
Gwenael M.D.J.-M. Gaussand
2011-04-01
Full Text Available From a pool of transgenic Arabidopsis (Arabidopsis thaliana plants harboring an activator T-DNA construct, one mutant was identified that developed spontaneous necrotic spots (sns-D on the rosette leaves under aseptic conditions. The sns-D mutation is dominant and homozygous plants are embryo lethal. The mutant produced smaller rosettes with a different number of stomata than the wild-type. DNA fragmentation in the nuclei of cells in the necrotic spots and a significant increase of caspase-3 and caspase-6 like activities in sns-D leaf extracts indicated that the sns-D mutation caused programmed cell death (PCD. The integration of the activator T-DNA caused an increase of the expression level of At1g13020, which encodes the eukaryotic translation initiation factor eIF4B2. The expression level of eIF4B2 was positively correlated with the severity of sns-D mutant phenotype. Overexpression of the eIF4B2 cDNA mimicked phenotypic traits of the sns-D mutant indicating that the sns-D mutant phenotype is indeed caused by activation tagging of eIF4B2. Thus, incorrect regulation of translation initiation may result in PCD.
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TRANSVERSE PHASE SPACE PAINTING FOR SNS ACCUMULATOR RING INJECTION.
Energy Technology Data Exchange (ETDEWEB)
BEEBE-WANG,J.; LEE,Y.Y.; RAPARIA,D.; WEI,J.
1999-03-29
The result of investigation and comparison of a series of transverse phase space painting schemes for the injection of SNS accumulator ring [1] is reported. In this computer simulation study, the focus is on the creation of closed orbit bumps that give desired distributions at the target. Space charge effects such as tune shift, emittance growth and beam losses are considered. The results of pseudo end-to-end simulations from the injection to the target through the accumulator ring and Ring to Target Beam Transfer (RTBT) system [2] are presented and discussed.
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United States and European students’ social-networking site activities and academic performance
Karpinski, Aryn; Kirschner, Paul A.; Shreffler, Anthony; Albert, Patricia; Tomko, Carrie
2018-01-01
Different cultures communicate differently. Research is beginning to examine the differences in culture related to social-networking site (SNS) use. Differences in specific SNS activities related to academic performance among United States (US; n = 446) and European (n = 394) university students
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Influence of complexing agent (Na2EDTA on chemical bath deposited Cu4SnS4 thin films
Directory of Open Access Journals (Sweden)
Anuar Kassim
2010-08-01
Full Text Available The quality of thin film is influenced by the presence of complexing agents such as Na2EDTA. The Cu4SnS4 thin films were deposited onto indium tin oxide glass substrate by chemical bath deposition method. The structural, morphological and optical properties of the deposited films have been studied using X-ray diffraction, atomic force microscopy and UV-Vis spectrophotometer, respectively. The XRD data showed that the films have a polycrystalline and orthorhombic structure. It also indicated that the most intense peak at 2 θ = 30.2° which belongs to (221 plane of Cu4 SnS4. The film deposited with 0.05 M Na2 EDTA showed good uniformity, good surface coverage with bigger grains and produced higher absorbance value. The band gap energy varies with the variation of Na2EDTA concentration which ranging from 1.56-1.60 eV. Deposition at concentration of 0.05 M Na2EDTA proved to offer a reasonably good Cu4SnS4 thin film.
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Energy Technology Data Exchange (ETDEWEB)
Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL; Harris, Gary [Howard University; Piazza, Fabrice [Pontifica Universidad Catolica Madre y Maestra, Dominican Republic
2013-01-01
Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development
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Status of the Cryogenic System Commissioning at SNS
Casagrande, Fabio; Campisi, Isidoro E; Creel, Jonathan; Dixon, Kelly; Ganni, Venkatarao; Gurd, Pamela; Hatfield, Daniel; Howell, Matthew; Knudsen, Peter; Stout, Daniel; Strong, William
2005-01-01
The Spallation Neutron Source (SNS) is under construction at Oak Ridge National Laboratory. The cold section of the Linac consists of 81 superconducting radio frequency cavities cooled to 2.1K by a 2400 Watt cryogenic refrigeration system. The major cryogenic system components include warm helium compressors with associated oil removal and gas management, 4.5K cold box, 7000L liquid helium dewar, 2.1K cold box (consisting of 4 stages of cold compressors), gaseous helium storage, helium purification and gas impurity monitoring system, liquid nitrogen storage and the cryogenic distribution transfer line system. The overall system commissioning strategy and status will be presented.
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Assili, Kawther; Alouani, Khaled; Vilanova, Xavier
2017-11-01
Tin sulfide (SnS) thin films were chemically deposited over silicon substrate in a temperature range of 250 °C-400 °C. The effects of deposition temperature on the structural, morphological and optical properties of the films were evaluated. All films present an orthorhombic SnS structure with a preferred orientation along (040). High absorption coefficients (in the range of 105 cm-1) were found for all obtained films with an increase in α value when deposition temperature decreases. Furthermore, the effects of substrate type were investigated based on comparison between the present results and those obtained for SnS films grown under the same deposition conditions but over glass substrate. The results suggest that the formation of SnS films onto glass substrate is faster than onto silicon substrate. It is found that the substrate nature affects the orientation growth of the films and that SnS films deposited onto Si present more defects than those deposited onto glass substrate. The optical transmittance is also restricted by the substrate type, mostly below 1000 nm. The obtained results for SnS films onto silicon suggest their promising integration within optoelectronic devices.
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Nolan, Samantha; Hendricks, Joyce; Towell, Amanda
2015-09-01
to explore the use of social networking sites (SNS) by adolescent mothers in Western Australia (WA) in relation to social support and the building of social capital. a constructionist narrative inquiry approach was employed to guide the research design and processes. Approval was gained from the university human ethics department. Sampling was purposeful and data were collected using in-depth interviews with seven adolescent mothers in WA. interviews were undertaken within the homes of adolescent mothers across WA. from within three fundamental domains of social support; tangible, emotional and informational support, provided by SNS use, five key themes were identified from the narratives. 'Social connectedness' was identified as a form of tangible support, sometimes termed 'practical' or 'instrumental' support. This theme incorporates connectedness with family, friends, and peers and across new and existing social groups. Three themes were identified that relate to emotional support; 'increased parenting confidence'; 'reduced parental stress' and 'enhanced self-disclosure' afforded by use of SNS. 'Access to information' was identified in terms of informational support, with participants often highlighting SNS use as their primary portal for information and advice. the findings of this study suggest that SNS use affords adolescent mothers in WA access to tangible, informational and emotional support and thus is a valuable source of social capital for these mothers. This study provides a platform for further exploration into this phenomenon, and possible implications include the potential for midwives and health care professionals to promote the benefits of SNS use with, and for, this group of mothers, or to incorporate SNS use into modern health care practices to further develop the potential for improved social capital related outcomes for them. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Electronic structure of SnS deduced from photoelectron spectra and band-structure calculations
Ettema, A.R.H.F.; Groot, R.A. de; Haas, C.; Turner, T.S.
1992-01-01
SnS is a layer compound with a phase transition from a high-temperature β phase to a low-temperature α phase with a lower symmetry. Ab initio band-structure calculations are presented for both phases. The calculations show that the charge distributions in the two phases are very similar. However,
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Arulanantham, A. M. S.; Valanarasu, S.; Jeyadheepan, K.; Ganesh, V.; Shkir, Mohd
2018-01-01
Herein we report a well-organized analysis on various key-properties of SnS thin films for solar cell fabricated by nebulizer spray pyrolysis technique. X-ray diffraction study reveals the polycrystalline nature of deposited films with orthorhombic crystal structure. The crystallite size was calculated and observed to be in the range of 8-28 nm with increasing molarity of precursor solution. The stoichiometry composition of SnS was confirmed by EDX study. SEM/AFM studies divulge the well-covered deposited surface with spherical grains and the size of grains is increasing with concentration and so the roughness. A remarkable decrease in band gap from 2.6 eV to 1.6 eV was noticed by raising the molar concentration from 0.025 M up to 0.075 M. A single strong emission peak at about 825 nm is observed in PL spectra with enhanced intensity which may be attributed to near band edge emission. From the Hall effect measurement, it was found that the SnS thin film exhibits p-type conductivity. The calculated values of resistivity and carrier concentration are 0.729 Ω cm and 3.67 × 1018/cm3 respectively. Furthermore, to study the photovoltaic properties of SnS thin films a heterojunction solar cell, FTO/n-CdS/p-SnS was produced and the conversion efficiency was recorded about 0.01%.
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Optimization of the SNS magnetism reflectometer neutron-guide optics using Monte Carlo simulations
Klose, F
2002-01-01
The magnetism reflectometer at the spallation neutron source SNS will employ advanced neutron optics to achieve high data rate, improved resolution, and extended dynamic range. Optical components utilized will include a multi-channel polygonal curved bender and a tapered neutron-focusing guide section. The results of a neutron beam interacting with these devices are rather complex. Additional complexity arises due to the spectral/time-emission profile of the moderator and non-perfect neutron optical coatings. While analytic formulae for the individual components provide some design guidelines, a realistic performance assessment of the whole instrument can only be achieved by advanced simulation methods. In this contribution, we present guide optics optimizations for the magnetism reflectometer using Monte Carlo simulations. We compare different instrument configurations and calculate the resulting data rates. (orig.)
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The RF power system for the SNS linac
International Nuclear Information System (INIS)
Tallerico, P.J.; Reass, W.A.
1998-01-01
The initial goal of the SNS project is to produce a 1 MW average beam of protons with short pulse lengths onto a neutron-producing target. The objective of the SNS RF system is to generate 117 MW peak of pulsed 805 MHz microwave power with an accelerated beam pulse length of 1.04 ms at a 60 Hz repetition rate. The power system must be upgradeable in peak power to deliver 2 MW average power to the neutron target. The RF system also requires about 3 MW peak of RF power at 402.5 MHz, but that system is not discussed here. The design challenge is to produce an RF system at minimum cost, that is very reliable and economical to operate. The combination of long pulses and high repetition rates make conventional solutions, such as the pulse transformer and transmission line method, very expensive. The klystron, with a modulating anode, and 1.5 MW of peak output power is the baseline RF amplifier, an 56 are required in the baseline design. The authors discuss four power system configurations that are the candidates for the design. The baseline design is a floating-deck modulating anode system. A second power system being investigated is the fast-pulsed power supply, that can be turned on and off with a rise time of under 0.1 ms. This could eliminate the need for a modulator, and drastically reduce the energy storage requirements. A third idea is to use a pulse transformer with a series IGBT switch and a bouncer circuit on the primary side, as was done for the TESLA modulator. A fourth method is to use a series IGBT switch at high voltage, and not use a pulse transformer. The authors discuss the advantages and problems of these four types of power systems, but they emphasize the first two
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Research on SNS and Education: The State of the Art and Its Challenges
Rodríguez-Hoyos, Carlos; Haya Salmón, Ignacio; Fernández-Díaz, Elia
2015-01-01
This paper presents, for further discussion, a review of the scientific literature produced internationally on the use of Social Network Sites (SNS) in different levels of education and settings. A total of 62 articles published in international scientific journals with peer review have been analysed. The main objective of this paper is to discuss…
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Electric field effect on the critical current of SNS-contact
International Nuclear Information System (INIS)
Rakhmanov, A.L.; Rozhkov, A.V.
1995-01-01
Electric field effect on the SNS-contact critical current is investigated in the Ginzburg-Landau theory approximation. It is shown that the electric field may cause a notable increase of the contact critical current especially if the sample temperature is close to the temperature of a superconducting transition of T sc normal layer. Electric field effect is increased with the reduction of film thickness, but it can strong enough for thick films as well at temperature close to T sc . 11 refs.; 4 figs
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Directory of Open Access Journals (Sweden)
Suder Seili
2017-12-01
Full Text Available The aim of this interdisciplinary paper is to study the social reality surrounding the data processing practices employers and employees engage in on social networking sites (SNS. Considering the lack of empirical studies, as well as the considerable uncertainty in the way personal data protection is implemented across the European Union (EU, the paper offers insights on the topic. Qualitative text analysis of semi-structured interviews with employers from the service sector (N=10 and the field of media and communication (N=15, as well as employers from organisations which had experienced various problems due to things their employees had posted on social media (N=14, and employees from the financial sector (N=15 were carried out to explore whether the data protection principles, which can be viewed as the most important guidelines for employers in the EU, are actually followed in their everyday SNS data processing practices. Even though the data protection principles emphasise the need for fair, purposeful, transparent, minimal and accurate processing of personal data, our interviews with employers and employees reveal that the actual SNS processing practices rarely live up to the standards. Our findings indicate that there is a growing mismatch between the social reality and legal requirements regarding data subjects.
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Lui, Dong; Kirschner, Paul A.; Karpinski, Aryn
2018-01-01
This meta-analysis explores the relationship between SNS-use and academic performance. Examination of the literature containing quantitative measurements of both SNS-use and academic performance produced a sample of 28 effects sizes (N ¼ 101,441) for review. Results indicated a significant
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International Nuclear Information System (INIS)
Lynch, M.; Kwon, S.
2001-01-01
A high-intensity proton linac, such as that being planned for the SNS, requires accurate RF control of cavity fields for the entire pulse in order to avoid beam spill. The current design requirement for the SNS is RF field stability within ±0.5% and ±0.5 o [1]. This RF control capability is achieved by the control electronics using the excess RF power to correct disturbances. To minimize the initial capital costs, the RF system is designed with 'just enough' RF power. All the usual disturbances exist, such as beam noise, klystron/HVPS noise, coupler imperfections, transport losses, turn-on and turn-off transients, etc. As a superconducting linac, there are added disturbances of large magnitude, including Lorentz detuning and microphonics. The effects of these disturbances and the power required to correct them are estimated, and the result shows that the highest power systems in the SNS have just enough margin, with little or no excess margin
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First-principles study of SnS electronic properties using LDA, PBE and HSE06 functionals
Ibragimova, R.; Ganchenkova, M.; Karazhanov, S.; Marstein, E. S.
2018-03-01
Recently, tin sulphide (SnS) has emerged as a promising alternative to conventional CIGS and CZTC for use in solar cells, possessing such properties as non-toxicity, low cost and production stability. SnS has a high theoretically predicted efficiency above 20%, but the experimentally achieved efficiency so far is as low as 4.36%. The reason for the low achieved efficiency is unclear. One of the powerful tools to get deeper insights about the nature of the problem is first-principles calculation approaches. That is why SnS has become an attractive subject for first-principles calculations recently. Previously calculated data, however, show a widespread of such fundamental value as the bandgap varying from 0.26 to 1.26 eV. In order to understand a reason for that, in this work, we concentrate on a systematic study of calculation parameters effects on the resulting electronic structure, with the particular attention paid to the influence of the exchange-correlation functional chosen for calculations. Several exchange-correlation functionals (LDA, PBE and HSE06) were considered. The systematic analysis has shown that the bandgap variation can result from a tensile/compressive hydrostatic pressure introduced by non-equilibrium lattice parameters used for the calculations. The study of the applicability of three functionals has shown that HSE06 gives the best match to both experimentally obtained bandgap and the XPS valence band spectra. LDA underestimates the bandgap but qualitatively reproduces experimentally measured valence DOS similar to that of HSE06 in contrast to PBE. PBE underestimates the bandgap and does not match to the measured XPS spectra.
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Ariswan; Sutrisno, H.; Prasetyawati, R.
2017-05-01
Thin films of SnSe and SnS semiconductors had been prepared by vacuum evaporation techniques. All prepared samples were characterized on their structure, optical, and electrical properties in order to know their application in technology. The crystal structure of SnSe and SnS was determined by X-Ray Diffraction (XRD) instrument. The morphology and chemical composition were obtained by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive of X-Ray Analysis (EDAX). The optical property such as band gap was determined by DR-UV-Vis (Diffuse Reflectance-Ultra Violet-Visible) spectroscopy, while the electrical properties were determined by measuring the conductivity by four probes method. The characterization results indicated that both SnSe and SnS thin films were polycrystalline. SnSe crystallized in an orthorhombic crystal system with the lattice parameters of a = 11.47 Å, b = 4.152 Å and c = 4.439 Å, while SnS had an orthorhombic crystal system with lattice parameters of a = 4.317 Å, b = 11.647 Å and c = 3.981 Å. Band gaps (Eg) of SnSe and SnS were 1.63 eV and 1.35 eV, respectively. Chemical compositions of both thin films were non-stoichiometric. Molar ratio of Sn : S was close to ideal which was 1 : 0.96, while molar ratio of Sn : S was 1 : 0.84. The surface morphology described the arrangement of the grains on the surface of the thin film with sizes ranging from 0.2 to 0.5 microns. Color similarity on the surface of the SEM images proved a homogenous thin layer.
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International Nuclear Information System (INIS)
Bonnie Madre; Charles Reece; Joseph Ozelis; Valerie Bookwalter
2003-01-01
Jefferson Lab has developed a web-based system that integrates commercial database, data analysis, document archiving and retrieval, and user interface software, into a coherent knowledge management product (Pansophy). This product provides important tools for the successful pursuit of major projects such as accelerator system development and construction, by offering elements of process and procedure control, data capture and review, and data mining and analysis. After a period of initial development, Pansophy is now being used in Jefferson Lab's SNS superconducting linac construction effort, as a means for structuring and implementing the QA program, for process control and tracking, and for cryomodule test data capture and presentation/analysis. Development of Pansophy is continuing, in particular data queries and analysis functions that are the cornerstone of its utility
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Superconducting cavity development at RRCAT
International Nuclear Information System (INIS)
Joshi, S.C.
2015-01-01
Raja Ramanna Centre for Advanced Technology (RRCAT), Indore pursuing a program on 'R and D Activities for High Energy Proton Linac based Spallation Neutron Source'. Spallation neutron source (SNS) facility will provide high flux pulse neutrons for research in the areas of condensed matter physics, materials science, chemistry, biology and engineering. This will complement the existing synchrotron light source facility, INDUS-2 at RRCAT and reactor based neutron facilities at BARC. RRCAT is also participating in approved mega project on 'Physics and Advanced Technology for High Intensity Proton Accelerator' to support activities of Indian Institutions - Fermilab Collaboration (IIFC). The SNS facility will have a 1 GeV superconducting proton injector linac and 1 GeV accumulator ring. The linac will comprise of large number of superconducting radio-frequency (SCRF) cavities operating at different RF frequencies housed in suitable cryomodules. Thus, an extensive SCRF cavity infrastructure setup is being established. In addition, a scientific and technical expertise are also being developed for fabrication, processing and testing of the SCRF cavities for series production. The paper presents the status of superconducting cavity development at RRCAT
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Energy Technology Data Exchange (ETDEWEB)
C. AMMERMAN; J. BERNARDIN
1999-11-01
This report presents results for design and analysis of the hot model water cooling system for the Spallation Neutron Source (SNS) coupled-cavity linac (CCL). The hot model, when completed, will include segments for both the CCL and coupled-cavity drift-tube linac (CCDTL). The scope of this report encompasses the modeling effort for the CCL portion of the hot model. This modeling effort employed the SINDA/FLUINT network modeling tool. This report begins with an introduction of the SNS hot model and network modeling using SINDA/FLUINT. Next, the development and operation of the SINDA/FLUINT model are discussed. Finally, the results of the SINDA/FLUINT modeling effort are presented and discussed.
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Teacher-student Relationship and SNS-mediated Communication: Perceptions of both role-players
Directory of Open Access Journals (Sweden)
Arnon Hershkovitz
2015-12-01
Full Text Available Teacher-student relationships are vital for academic and social development of students, for teachers’ professional and personal development, and for having a supportive learning environment. In the digital age, these relationships can extend beyond bricks and mortar and beyond school hours. Specifically, these relationships are extended today while teachers and students communicate via social networking sites (SNS. This paper characterizes differences between teachers (N=160 and students (N=587 who are willing to connect with their students/teachers via Facebook and those who do not wish to connect. The quantitative research reported here within is based on data collection of personal characteristics, attitudes towards Facebook, and perceptions of teacher-student relationship. Findings suggest differences in characteristics of the two groups (willing to connect vs. not willing to connect within both populations (teachers and students. Also, in both populations, those who were willing to connect, compared to those who were not willing to connect, present more positive attitudes towards using Facebook for teaching/learning and are more opposed to a banning policy of student-teacher SNS-based communication. We also found that students who were willing to connect showed a greater degree of closeness with their teachers compared to those who were not willing to connect. This study may assist policymakers when setting up regulations regarding teacher-student communication via social networking sites.
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Electronic and magnetic properties of SnS2 monolayer doped with 4d transition metals
Xiao, Wen-Zhi; Xiao, Gang; Rong, Qing-Yan; Chen, Qiao; Wang, Ling-Ling
2017-09-01
We investigate the electronic structures and magnetic properties of SnS2 monolayers substitutionally doped with 4-d transition-metal through systematic first principles calculations. The doped complexes exhibit interesting electronic and magnetic behaviors, depending on the interplay between crystal field splitting, Hund's rule, and 4d levels. The system doped with Y is nonmagnetic metal. Both the Zr- and Pd-doped systems remain nonmagnetic semiconductors. Doping results in half-metallic states for Nb-, Ru-, Rh-, Ag, and Cd doped cases, and magnetic semiconductors for systems with Mo and Tc dopants. In particular, the Nb- and Mo-doped systems display long-ranged ferromagnetic ordering with Curie temperature above room temperature, which are primarily attributable to the double-exchange mechanism, and the p-d/p-p hybridizations, respectively. Moreover, The Mo-doped system has excellent energetic stability and flexible mechanical stability, and also possesses remarkable dynamic and thermal (500 K) stability. Our studies demonstrate that Nb- and Mo-doped SnS2 monolayers are promising candidates for preparing 2D diluted magnetic semiconductors, and hence will be a helpful clue for experimentalists.
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EXPLORING TRANSVERSE BEAM STABILITY IN THE SNS IN THE PRESENCE OF SPACE CHARGE.
Energy Technology Data Exchange (ETDEWEB)
FEDOTOV,A.V.; BLASKIEWICZ,M.; WEI,J.; DANILOV,V.; HOLMES,J.; SHISHLO,A.
2002-06-03
The highest possible intensity in the machine is typically determined by the onset of coherent beam instabilities. Understanding the contribution of various effects to the damping and growth of such instabilities in the regime of strong space charge is thus of crucial importance. In this paper we explore transverse beam stability by numerical simulations using recently implemented models of transverse impedance and three-dimensional space charge. Results are discussed with application to the SNS accumulators.
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International Nuclear Information System (INIS)
Deshpande, N.G.; Sagade, A.A.; Gudage, Y.G.; Lokhande, C.D.; Sharma, Ramphal
2007-01-01
Thin films of tin disulfide (SnS 2 ) have been deposited by using low cost successive ionic layer adsorption and reaction (SILAR) technique. The deposition parameters such as SILAR cycles (60), immersion time (20 s), rinsing time (10 s) and deposition temperature (27 o C) were optimized to obtain good quality of films. Physical investigations were made to study the structural, optical and electrical properties. X-ray diffraction (XRD) patterns reveal that the deposited SnS 2 thin films have hexagonal crystal structure. Energy dispersive X-ray analysis (EDAX) indicated elemental ratio close to those for tin disulfide (SnS (2.02) ). Uniform deposition of the material over the entire glass substrate was revealed by scanning electron microscopy (SEM). Atomic force microscopy (AFM) showed the film is uniform and the substrate surface is well covered with small spherical grains merged in each other. A direct band gap of 2.22 eV was obtained. Photoluminescence (PL) showed two strong peaks corresponding to green and red emission. Ag/SnS 2 junction showed Schottky diode like I-V characteristics. The barrier height calculated was 0.22 eV. Thermoelectric power (TEP) properties showed that tin disulfide exhibits n-type conductivity
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Neural network based approach for tuning of SNS feedback and feedforward controllers
International Nuclear Information System (INIS)
Kwon, Sung-Il; Prokop, Mark S.; Regan, Amy H.
2002-01-01
The primary controllers in the SNS low level RF system are proportional-integral (PI) feedback controllers. To obtain the best performance of the linac control systems, approximately 91 individual PI controller gains should be optimally tuned. Tuning is time consuming and requires automation. In this paper, a neural network is used for the controller gain tuning. A neural network can approximate any continuous mapping through learning. In a sense, the cavity loop PI controller is a continuous mapping of the tracking error and its one-sample-delay inputs to the controller output. Also, monotonic cavity output with respect to its input makes knowing the detailed parameters of the cavity unnecessary. Hence the PI controller is a prime candidate for approximation through a neural network. Using mean square error minimization to train the neural network along with a continuous mapping of appropriate weights, optimally tuned PI controller gains can be determined. The same neural network approximation property is also applied to enhance the adaptive feedforward controller performance. This is done by adjusting the feedforward controller gains, forgetting factor, and learning ratio. Lastly, the automation of the tuning procedure data measurement, neural network training, tuning and loading the controller gain to the DSP is addressed.
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Effect of a magnetic field on the excess resistance of SNS sandwiches
International Nuclear Information System (INIS)
Logvenov, G.Y.; Ryazanov, V.V.
1983-01-01
The contribution of superconducting plates to the resistance of Ta--Cu--Ta sandwiches in the presence of a magnetic field of up to 170 Ge is investigated. Near the superconducting transition temperature T/sub c/H, the Ta used was in a mixed (vortical) state. It is shown that the presence of gradients of the order parameter near the Abrikosov vortices appreciably changes the penetration depth of a longitudinal electric field into the superconductor and leads to a corresponding change in the excess resistance of SNS sandwiches
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Ultraviolet emission from low resistance Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires
Directory of Open Access Journals (Sweden)
E. Karageorgou
2014-11-01
Full Text Available SnO2 and Sn:In2O3 nanowires were grown on Si(001, and p-n junctions were fabricated in contact with p-type Cu2S which exhibited rectifying current–voltage characteristics. Core-shell Cu2SnS3/SnO2 and CuInS2/Sn:In2O3 nanowires were obtained by depositing copper and post-growth processing under H2S between 100 and 500 °C. These consist mainly of tetragonal rutile SnO2 and cubic bixbyite In2O3. We observe photoluminescence at 3.65 eV corresponding to band edge emission from SnO2 quantum dots in the Cu2SnS3/SnO2 nanowires due to electrostatic confinement. The Cu2SnS3/SnO2 nanowires assemblies had resistances of 100 Ω similar to CuInS2/In2O3 nanowires which exhibited photoluminescence at 3.0 eV.
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Banotra, Arun; Padha, Naresh; Kumar, Shiv; Kapoor, Ashok K.
2018-05-01
Thin films of SnS have been obtained from Sn and S powders which were mixed up using ball mill technique with and without evaporating additional sulphur prior to annealing at 523K. The obtained samples were taken for structural, optical, chemical and morphological studies. The X-ray diffraction reveals the formation of SnS phase on annealing in vacuum having S/Sn ratio of 0.67 obtained from EDAX. This deficit in `S' is removed by supplementing additional `S' of 200nm prior to annealing which results in the S/Sn ratio of 1.01. The optical transmission recorded from spectrophotometer used to study different optical parameters. Morphological results corroborate well with the XRD, EDAX and optical study. The obtained stoichiometric films were also tested for Ag/p-SnS Schottky diodes on In coated glass substrates using current voltage measurements.
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The Fermilab CMTF cryogenic distribution remote control system
Energy Technology Data Exchange (ETDEWEB)
Pei, L.; Theilacker, J.; Klebaner, A.; Martinez, A.; Bossert, R. [Fermi National Accelerator Laboratory Batavia, IL, 60510 (United States)
2014-01-29
The Cryomodule Test Facility (CMTF) is able to provide the necessary test bed for measuring the performance of Superconducting Radio Frequency (SRF) cavities in a cryomodule (CM). The CMTF have seven 300 KW screw compressors, two liquid helium refrigerators, and two Cryomodule Test Stands (CMTS). CMTS1 is designed for 1.3 GHz cryomodule operating in a pulsed mode (PM) and CMTS2 is for cryomodule operating in Half-Wave (HW) and Continuous Wave (CW) mode. Based on the design requirement, each subsystem has to be far away from each other and be placed in distant locations. Therefore choosing Siemens Process Control System 7-400, DL205 PLC, Synoptic and Fermilab ACNET are the ideal choices for CMTF cryogenic distribution real-time remote control system. This paper presents a method which has been successfully used by many Fermilab distribution cryogenic real-time remote control systems.
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Electron-cloud updated simulation results for the PSR, and recent results for the SNS
International Nuclear Information System (INIS)
Pivi, M.; Furman, M.A.
2002-01-01
Recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos are presented in this paper. A refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has recently been included in the electron-cloud code
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Casida, Jesus M; Crane, Patrick C; Walker, Tara L; Wargo, Lisa M
2012-01-01
The leadership-culture phenomenon, a known explanatory construct for organizational performance, is understudied in nursing. Building on our previous work, we further addressed this knowledge gap through explorations of demographics and hospital variables which may have a significant influence on staff nurses' (SNs) perceptions of their nurse managers' (NMs) leadership and nursing unit culture. Furthermore, we explored the extent to which the NMs' leadership predicted specific cultures which typify nursing unit effectiveness. Using dissertation data provided by278 SNs, we found that SNs educated at the baccalaureate level or higher had favorable perceptions of their nursing unit performance and viewed their NMs' leadership differently than the SNs with diploma or associate degrees. The frequent portrayals of transformational (TFL) leadership behaviors (e.g., visionary) by the NMs were paramount in shaping culture traits which exemplify high performance outcomes. TFL leaders were more likely to shape unit cultures which are flexible and adaptive to the environmental challenges within and outside the nursing unit. Thus, the type of NMs' leadership and unit culture may provide an added value in explaining the performance level in patient care units which consequently affects the overall hospital/organizational outcomes. Implications for research and leadership practices are presented.
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Nolan, Samantha; Hendricks, Joyce; Williamson, Moira; Ferguson, Sally
2018-07-01
to explore ways in which midwives can enhance the support provided by social networking sites for adolescent mothers. a narrative approach was employed to guide the research design and processes. Approval was obtained from Edith Cowan University human ethics department. focus groups and interviews were undertaken with adolescent mothers and midwives in Western Australia. the four key themes identified across both groups were validation by midwives, importance of ownership, enhanced community connections and the importance of guideline development. findings suggest both mothers and midwives consider there are a variety of ways in which healthcare professionals could enhance the support afforded to adolescent mothers by their use of SNS. Midwives were more likely to consider the need for guideline development, but the underlying value of accessible, professionally mediated online support and information was consistent across the two groups. Midwives would benefit from acknowledging the role played by SNS in providing support to adolescent mothers and by considering ways in which this technology can be used to lend further support to this group of mothers. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Performance of a reentrant cavity beam position monitor
Directory of Open Access Journals (Sweden)
Claire Simon
2008-08-01
Full Text Available The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs. In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryomodule, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10 μm and has the possibility to perform bunch to bunch measurements for the x-ray free electron laser (X-FEL and the International Linear Collider (ILC. Its other features are a small size of the rf cavity, a large aperture (78 mm, and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH, at Deutsches Elektronen-Synchrotron (DESY and demonstrated its operation at cryogenic temperature inside a cryomodule. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4 μm over a dynamic range ±5 mm in single bunch.
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Performance of a reentrant cavity beam position monitor
International Nuclear Information System (INIS)
Simon, C.; Luong, M.; Chel, S.; Napoly, O.; Novo, J.; Roudier, D.; Rouviere, N.; Baboi, N.; Mildner, N.; Nolle, D.
2008-01-01
The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryo-module, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10 μm and has the possibility to perform bunch to bunch measurements for the X-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryo-module. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4 μm over a dynamic range ± 5 mm in single bunch. (authors)
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Performance of a reentrant cavity beam position monitor
Simon, Claire; Luong, Michel; Chel, Stéphane; Napoly, Olivier; Novo, Jorge; Roudier, Dominique; Rouvière, Nelly; Baboi, Nicoleta; Mildner, Nils; Nölle, Dirk
2008-08-01
The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryomodule, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10μm and has the possibility to perform bunch to bunch measurements for the x-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryomodule. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4μm over a dynamic range ±5mm in single bunch.
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Effect of the Tuner on the Field Flatness of SNS Superconducting RF Cavities
Sun, A
2004-01-01
Field flatness in a multi-cell superconducting cavity affects not only the net accelerating voltage, but also the peak surface field and the Lorenz Force detuning coefficient. Our measurement indicates that the field flatness changes both external Q of the Fundamental Power Coupler (FPC) and external Q of the Field Probe (FP). The field amplitude tilts linearly to the distance between the cell center and the cavitys geometry center (pivot point). The tilt rate has been measured in a cryomodule cold (2 K) test, being about 2%/100 kHz, relative the field flatness at the cavitys center frequency of 805 MHz. Bead-pull measurements confirmed that the field flatness change is 2.0%/100 kHz for a medium β cavity with helium vessel, and 1.72%/100 kHz without helium vessel. These results matched the predictions of simulations using ANSYS and SUPERFISH. A detailed analysis reveals that longitudinal capacitive gap deformation is the main cause of the frequency change. Field flatness change ...
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RF Beam Position Monitor for the SNS Ring
International Nuclear Information System (INIS)
Vetter, Kurt; Cameron, Peter; Dawson, Craig; Degen, Chris; Kesselman, Martin; Mead, Joseph
2004-01-01
The Spallation Neutron Source Ring accumulates 1060 pulses of 38-mA peak current 1-GeV H-minus particles from the Linac through the HEBT line, then delivers this accumulated beam in a single pulse to a mercury target via the RTBT line. The dynamic range over the course of the accumulation cycle is 60 dB. As a result of particle energy distribution the 402.5-MHz RF bunching frequency quickly de-coheres during the first few turns. In order to measure first-turn position a dual-mode BPM has been designed to process 402.5-MHz signal energy during the first few turns then switch to a Baseband mode to process de-cohered energy in the low MHz region. The design has been implemented as a dual mother/daughter board PCI architecture. Both Baseband and RF calibration are included on the RF BPM board. A prototype system has been installed in the SNS Linac
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Ion Source Development at the SNS
International Nuclear Information System (INIS)
Welton, R. F.; Han, B. X.; Kenik, E. A.; Murray, S. N.; Pennisi, T. R.; Potter, K. G.; Lang, B. R.; Santana, M.; Stockli, M. P.; Desai, N. J.
2011-01-01
The Spallation Neutron Source (SNS) now routinely operates near 1 MW of beam power on target with a highly-persistent ∼38 mA peak current in the linac and an availability of ∼90%. The ∼1 ms-long, 60 Hz, ∼50 mA H - beam pulses are extracted from a Cs-enhanced, multi-cusp, RF-driven, internal-antenna ion source. An electrostatic LEBT (Low Energy Beam Transport) focuses the 65 kV beam into the RFQ accelerator. The ion source and LEBT have normally a combined availability of ∼99%. Although much progress has been made over the last years to achieve this level of availability further improvements are desirable. Failures of the internal antenna and occasionally impaired electron dump insulators require several source replacements per year. An attempt to overcome the antenna issues with an AlN external antenna source early in 2009 had to be terminated due to availability issues. This report provides a comprehensive review of the design, experimental history, status, and description of recently updated components and future plans for this ion source. The mechanical design for improved electron dump vacuum feedthroughs is also presented, which is compatible with the baseline and both external antenna ion sources.
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Energy Technology Data Exchange (ETDEWEB)
Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL
2014-01-01
Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a small foil about the size of a postage stamp is critical to the operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control film thickness. The results are discussed in the light of development of nanodiamond foils that
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Error studies for SNS Linac. Part 1: Transverse errors
International Nuclear Information System (INIS)
Crandall, K.R.
1998-01-01
The SNS linac consist of a radio-frequency quadrupole (RFQ), a drift-tube linac (DTL), a coupled-cavity drift-tube linac (CCDTL) and a coupled-cavity linac (CCL). The RFQ and DTL are operated at 402.5 MHz; the CCDTL and CCL are operated at 805 MHz. Between the RFQ and DTL is a medium-energy beam-transport system (MEBT). This error study is concerned with the DTL, CCDTL and CCL, and each will be analyzed separately. In fact, the CCL is divided into two sections, and each of these will be analyzed separately. The types of errors considered here are those that affect the transverse characteristics of the beam. The errors that cause the beam center to be displaced from the linac axis are quad displacements and quad tilts. The errors that cause mismatches are quad gradient errors and quad rotations (roll)
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1.3 GHz superconducting RF cavity program at Fermilab
Energy Technology Data Exchange (ETDEWEB)
Ginsburg, C.M.; Arkan, T.; Barbanotti, S.; Carter, H.; Champion, M.; Cooley, L.; Cooper, C.; Foley, M.; Ge, M.; Grimm, C.; Harms, E.; /Fermilab
2011-03-01
At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules (CMs) for Project X, an International Linear Collider (ILC), or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.
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The Inelastic Instrument suite at the SNS
International Nuclear Information System (INIS)
Granroth, Garrett E; Abernathy, Douglas L; Ehlers, Georg; Hagen, Mark E; Herwig, Kenneth W; Mamontov, Eugene; Ohl, Michael E; Wildgruber, Christoph U
2008-01-01
The instruments in the extensive suite of spectrometers at the SNS are in various stages of installation and commissioning. The Back Scattering Spectrometer (BASIS) is installed and is in commissioning. It's near backscattering analyzer crystals provide the 3 eV resolution as expected. BASIS will enter the user program in the fall of 2007. The ARCS wide angular-range thermal to epithermal neutron spectrometer will come on line in the fall of 2007 followed shortly by the Cold Neutron Chopper Spectrometer. These two direct geometry instruments provide moderate resolution and the ability to trade resolution for flux. In addition both instruments have detector coverage out to 140o to provide a large Q range. The SEQUOIA spectrometer, complete in 2008, is the direct geometry instrument that will provide fine resolution in the thermal to epithermal range. The Spin-Echo spectrometer, to be completed on a similar time scale, will provide the finest energy resolution worldwide. The HYSPEC spectrometer, available no later than 2011, will provide polarized capabilities and optimized flux in the thermal energy range. Finally, the Vision chemical spectrometer will use crystal analyzers to study energy transfers into the epithermal range
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The SNS/HFIR Web Portal System How Can it Help Me?
International Nuclear Information System (INIS)
Miller, Stephen D.; Geist, Al; Herwig, Kenneth W.; Peterson, Peter F.; Reuter, Michael A.; Ren, Shelly; Bilheux, Jean-Christophe; Campbell, Stuart I.; Kohl, James Arthur; Vazhkudai, Sudharshan S.; Cobb, John W.; Lynch, Vickie E.; Chen, Meili; Trater, James R.
2010-01-01
In a busy world, continuing with the status-quo, to do things the way we are already familiar, often seems to be the most efficient way to conduct our work. We look for the value-add to decide if investing in a new method is worth the effort. How shall we evaluate if we have reached this tipping point for change? For contemporary researchers, understanding the properties of the data is a good starting point. The new generation of neutron scattering instruments being built are higher resolution and produce one or more orders of magnitude larger data than the previous generation of instruments. For instance, we have grown out of being able to perform some important tasks with our laptops the data are too big and the computations would simply take too long. These large datasets can be problematic as facility users now begin to grapple with many of the same issues faced by more established computing communities. These issues include data access, management, and movement, data format standards, distributed computing, and collaboration among others. The Neutron Science Portal has been architected, designed, and implemented to provide users with an easy-to-use interface for managing and processing data, while also keeping an eye on meeting modern cybersecurity requirements imposed on institutions. The cost of entry for users has been lowered by utilizing a web interface providing access to backend portal resources. Users can browse or search for data which they are allowed to see, data reduction applications can be run without having to load the software, sample activation calculations can be performed for SNS and HFIR beamlines, McStas simulations can be run on TeraGrid and ORNL computers, and advanced analysis applications such as those being produced by the DANSE project can be run. Behind the scenes is a live cataloging system which automatically catalogs and archives experiment data via the data management system, and provides proposal team members access to their
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Effects and Correction of Closed Orbit Magnet Errors in the SNS Ring
Energy Technology Data Exchange (ETDEWEB)
Bunch, S.C.; Holmes, J.
2004-01-01
We consider the effect and correction of three types of orbit errors in SNS: quadrupole displacement errors, dipole displacement errors, and dipole field errors. Using the ORBIT beam dynamics code, we focus on orbit deflection of a standard pencil beam and on beam losses in a high intensity injection simulation. We study the correction of these orbit errors using the proposed system of 88 (44 horizontal and 44 vertical) ring beam position monitors (BPMs) and 52 (24 horizontal and 28 vertical) dipole corrector magnets. Correction is carried out numerically by adjusting the kick strengths of the dipole corrector magnets to minimize the sum of the squares of the BPM signals for the pencil beam. In addition to using the exact BPM signals as input to the correction algorithm, we also consider the effect of random BPM signal errors. For all three types of error and for perturbations of individual magnets, the correction algorithm always chooses the three-bump method to localize the orbit displacement to the region between the magnet and its adjacent correctors. The values of the BPM signals resulting from specified settings of the dipole corrector kick strengths can be used to set up the orbit response matrix, which can then be applied to the correction in the limit that the signals from the separate errors add linearly. When high intensity calculations are carried out to study beam losses, it is seen that the SNS orbit correction system, even with BPM uncertainties, is sufficient to correct losses to less than 10-4 in nearly all cases, even those for which uncorrected losses constitute a large portion of the beam.
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Microstructure and composition of a SNS Josephson junction using CaRuO3 as the metallic barrier
International Nuclear Information System (INIS)
Rozeveld, S.; Merkle, K.L.; Char, K.
1994-10-01
Superconductor - normal - superconductor (SNS) edge junctions consisting of YBa 2 Cu 3 O 7-x /CaRuO 3 /YBa 2 Cu 3 O 7-x were fabricated on (001) LaA1O 3 substrates. These devices display an excess interface resistance which is not well understood but is related to the SN interface and interlayer structure. High-resolution and conventional transmission electron microscopy were employed to investigate the SN interface to determine the structure and possible interface defects. Energy-loss spectroscopy and energy dispersive x-ray analysis were performed on the CaRuO 3 film and near interface regions to quantify the extent of interdiffusion between the CiRuO 3 and YBCO films. Changes in either the interface structure or the normal layer chemistry are expected to greatly influence the junction properties
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SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature
International Nuclear Information System (INIS)
Robert Rimmer; Jay Benesch; Joseph Preble; Charles Reece
2005-01-01
In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maintenance shutdown. We report on the overall SRF performance of the machine after these major disturbances and on efforts to characterize and optimize the new behavior for high-energy running
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Refined beam measurements on the SNS H- injector
Han, B. X.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stinson, C. M.; Stockli, M. P.
2017-08-01
The H- injector for the SNS RFQ accelerator consists of an RF-driven, Cs-enhanced H- ion source and a compact, two-lens electrostatic LEBT. The LEBT output and the RFQ input beam current are measured by deflecting the beam on to an annular plate at the RFQ entrance. Our method and procedure have recently been refined to improve the measurement reliability and accuracy. The new measurements suggest that earlier measurements tended to underestimate the currents by 0-2 mA, but essentially confirm H- beam currents of 50-60 mA being injected into the RFQ. Emittance measurements conducted on a test stand featuring essentially the same H- injector setup show that the normalized rms emittance with 0.5% threshold (99% inclusion of the total beam) is in a range of 0.25-0.4 mm.mrad for a 50-60 mA beam. The RFQ output current is monitored with a BCM toroid. Measurements as well as simulations with the PARMTEQ code indicate an underperforming transmission of the RFQ since around 2012.
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Lin, Ruoyun; Utz, Sonja
2017-01-01
On social media, users can easily share their feelings, thoughts, and experiences with the public, including people who they have no previous interaction with. Such information, though often embedded in a stream of others? news, may influence recipients? perception toward the discloser. We used a special design that enables a quasi-experience of SNS browsing, and examined if browsing other?s posts in a news stream can create a feeling of familiarity and (even) closeness toward the discloser. ...
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Idota, Hiroki; Minetaki, Kazunori; Bunno, Teruyuki; Tsuji, Masatsugu
2011-01-01
Recently social media such as Blog and SNS has been introducing by many firms for means of sharing information inside the firm, in particular to promote product and process innovation. This paper attempts to examine the relationship between social media and product innovation, and research questions are summarized as follows: (i) whether social capital influences the use of social media; (ii) whether social media promotes product innovation; and (iii) whether the effect of social media on pro...
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Neutronic Design Calculations on Moderators for the Spallation Neutron Source (SNS)
International Nuclear Information System (INIS)
Murphy, D.B.
1999-01-01
The Spallation Neutron Source (SNS) to be built at the Oak Ridge National Laboratory will provide an intense source of neutrons for a large variety of experiments. It consists of a high-energy (1-GeV) and high-power (∼1-MW) proton accelerator, an accumulator ring, together with a target station and an experimental area. In the target itself, the proton beam will produce neutrons via the spallation process and these will be converted to low-energy ( 2 O moderators. Extensive engineering design work has been conducted on the moderator vessels. For our studies we have produced realistic neutronic representations of these moderators. We report on neutronic studies conducted on these representations of the moderators using Monte Carlo simulation techniques
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Effect of thickness on electrical properties of SILAR deposited SnS thin films
Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba
2016-03-01
Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.
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Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab
International Nuclear Information System (INIS)
Shin, Ilkyoung; Satogata, Todd; Ahmed, Shahid; Bogacz, Slawomir; Stirbet, Mircea; Wang, Haipeng; Wang, Yan; Yunn, Byung; Bodenstein, Ryan
2012-01-01
Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.
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Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab
Energy Technology Data Exchange (ETDEWEB)
Ilkyoung Shin, Todd Satogata, Shahid Ahmed, Slawomir Bogacz, Mircea Stirbet, Haipeng Wang, Yan Wang, Byung Yunn, Ryan Bodenstein
2012-07-01
Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.
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Stenger, Thomas; Coutant, Alexandre
2009-01-01
Social Networks Sites (SNS) such as Facebook, MySpace, Skyrock.com or Linkedin have become new fields of investigation for marketing. Even though the phenomenon has met with an amazing popular success, only a few scientific works have been published on this subject. This article proposes initially to evaluate the situation by a review of the experts' discourses and, then, a an analysis of the texts in core disciplines specialising in social networks analysis (mainly sociometry, anthropology a...
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Anomalous Q(sub 0) Results in the CEBAF South Linac
International Nuclear Information System (INIS)
William J. Schneider; M. Drury; Joe Preble
1993-01-01
While in practice, the performance of cavities - Q(sub 0) versus E(sub acc) - in the assembled CEBAF cryomodule corresponds in nearly every respect to the performance as measured in the vertical test area; there are a few cases where this is not true. On six (6) of the twenty (20) cryomodules installed in the south linac, cavity 4 specifically, and one other cavity in cryomodule 7 have an anomalous low Q(sub 0). Investigation into the source of the low Q(sub 0) on these particular cavities have centered around trapped magnetic fields, slow cooldowns or maldistribution of He flow during cooldown leading to hydride precipitation and Q(sub 0) disease. Other possibilities such as low window Q(sub 0)'s or harmonic content of the klystron were also considered. A detailed investigation to understand the phenomena leading to the low Q(sub 0)'s on cryomodule 7 and 8 is discussed. We have found evidence suggesting cooldown dependent Q(sub 0) disease as well as window heating to account for some of the discrepancies but not all. A complete explanation of the problem is still under further investigation
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Piezoelectric Tuner Compensation of Lorentz Detuning in Superconducting Cavities
International Nuclear Information System (INIS)
Jean Delayen; Davis, G.
2003-01-01
Pulsed operation of superconducting cavities can induce large variations of the resonant frequency through excitation of the mechanical modes by the radiation pressure. The phase and amplitude control system must be able to accommodate this frequency variation; this can be accomplished by increasing the capability of the rf power source. Alternatively, a piezo electric tuner can be activated at the same repetition rate as the rf to counteract the effect of the radiation pressure. We have demonstrated such a system on the prototype medium beta SNS cryomodule with a reduction of the dynamic Lorentz detuning during the rf pulse by a factor of 3. Piezo electric tuners can also be used to reduce the level of microphonics in low-current cw accelerators. We have measured the amplitude and phase of the transfer function of the piezo control system (from input voltage to cavity frequency) up to several kHz
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Upgrade of the Cryogenic CERN RF Test Facility
Pirotte, O; Brunner, O; Inglese, V; Koettig, T; Maesen, P; Vullierme, B
2014-01-01
With the large number of superconducting radiofrequency (RF) cryomodules to be tested for the former LEP and the present LHC accelerator a RF test facility was erected early in the 1990’s in the largest cryogenic test facility at CERN located at Point 18. This facility consisted of four vertical test stands for single cavities and originally one and then two horizontal test benches for RF cryomodules operating at 4.5 K in saturated helium. CERN is presently working on the upgrade of its accelerator infrastructure, which requires new superconducting cavities operating below 2 K in saturated superfluid helium. Consequently, the RF test facility has been renewed in order to allow efficient cavity and cryomodule tests in superfluid helium and to improve its thermal performances. The new RF test facility is described and its performances are presented.
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Upgrade of the cryogenic CERN RF test facility
International Nuclear Information System (INIS)
Pirotte, O.; Benda, V.; Brunner, O.; Inglese, V.; Maesen, P.; Vullierme, B.; Koettig, T.
2014-01-01
With the large number of superconducting radiofrequency (RF) cryomodules to be tested for the former LEP and the present LHC accelerator a RF test facility was erected early in the 1990’s in the largest cryogenic test facility at CERN located at Point 18. This facility consisted of four vertical test stands for single cavities and originally one and then two horizontal test benches for RF cryomodules operating at 4.5 K in saturated helium. CERN is presently working on the upgrade of its accelerator infrastructure, which requires new superconducting cavities operating below 2 K in saturated superfluid helium. Consequently, the RF test facility has been renewed in order to allow efficient cavity and cryomodule tests in superfluid helium and to improve its thermal performances. The new RF test facility is described and its performances are presented
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Thermally evaporated thin films of SnS for application in solar cell devices
International Nuclear Information System (INIS)
Miles, Robert W.; Ogah, Ogah E.; Zoppi, Guillaume; Forbes, Ian
2009-01-01
SnS (tin sulphide) is of interest for use as an absorber layer and the wider energy bandgap phases e.g. SnS 2 , Sn 2 S 3 and Sn/S/O alloys of interest as Cd-free buffer layers for use in thin film solar cells. In this work thin films of tin sulphide have been thermally evaporated onto glass and SnO 2 :coated glass substrates with the aim of optimising the properties of the material for use in photovoltaic solar cell device structures. In particular the effects of source temperature, substrate temperature, deposition rate and film thickness on the chemical and physical properties of the layers were investigated. Energy dispersive X-ray analysis was used to determine the film composition, X-ray diffraction to determine the phases present and structure of each phase, transmittance and reflectance versus wavelength measurements to determine the energy bandgap and scanning electron microscopy to observe the surface topology and topography and the properties correlated to the deposition parameters. Using the optimised conditions it is possible to produce thin films of tin sulphide that are pinhole free, conformal to the substrate and that consist of densely packed columnar grains. The composition, phases present and the optical properties of the layers deposited were found to be highly sensitive to the deposition conditions. Energy bandgaps in the range 1.55 eV-1.7 eV were obtained for a film thickness of 0.8 μm, and increasing the film thickness to > 1 μm resulted in a reduction of the energy bandgap to less than 1.55 eV. The applicability of using these films in photovoltaic solar cell device structures is also discussed.
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International Nuclear Information System (INIS)
Chang, Shao-Wei; Ishikawa, Kaoru; Sugiyama, Mutsumi
2015-01-01
We propose using amorphous Zn–Sn–O (α-ZTO) deposited by RF sputtering as an alternative n-type buffer layer for Cu(In,Ga)Se 2 and SnS solar cells. The order of the carrier density, n, is increased from the order of 10 15 to 10 17 cm −1 as the Sn/(Sn + Zn) atomic ratio increases from 0.29 to 0.40. On the other hand, the order of n decreased from 10 17 to 10 11 cm −1 as the oxygen partial pressure increased from 0 to 10%. Further, for the α-ZTO film with the Sn/(Sn + Zn) atomic ratio at 0.38 and the oxygen partial pressure at 0%, valence band discontinuities of α-ZTO/CuInSe 2 and α-ZTO/SnS were determined using photoelectron yield spectroscopy measurements. The band discontinuities of each of these interfaces form a spike structure in the conduction band offset, which enables a high-performance solar cell to be obtained. - Highlights: • We propose using amorphous Zn–Sn–O as a n-type layer for Cu(In,Ga)Se 2 and SnS solar cells. • The carrier density was controlled by total and/or oxygen partial pressure during sputtering. • Valence band discontinuities of Zn–Sn–O/CuInSe 2 and Zn–Sn–O/SnS were determined. • The conduction band discontinuities of each of these interfaces form a spike structure
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Barasa, Sandra Nekesa
2010-01-01
This book examines the use of language in Computer Mediated Communication (CMC) genres in Kenya. It focuses on Short Messaging Service (SMS), Email, Instant Messages (IM) and Social Network Sites (SNS) genres. It presents an overview of the use and characteristics of Kenyan languages in CMC texts
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Precision Magnetic Elements for the SNS Storage Ring
International Nuclear Information System (INIS)
Danby, G.; Jackson, J.; Spataro, C.
1999-01-01
Magnetic elements for an accumulator storage ring for a 1 GeV Spallation Neutron Source (SNS) have been under design. The accumulation of very high intensity protons in a storage ring requires beam optical elements of very high purity to minimize higher order resonances in the presence of space charge. The parameters of the elements required by the accumulator lattice design have been reported. The dipoles have a 17 cm gap and are 124 cm long. The quadrupoles have a physical length to aperture diameter ratio of 40 cm/21 cm and of 45 cm/31 cm. Since the elements have a large aperture and short length, optimizing the optical effects of magnet ends is the major design challenge. Two dimensional (2D) computer computations can, at least on paper, produce the desired accuracy internal to magnets, i.e. constant dipole fields and linear quadrupole gradients over the desired aperture to 1 x 10 -4 . To minimize undesirable end effects three dimensional (3D) computations can be used to design magnet ends. However, limitations on computations can occur, such as necessary finite boundary conditions, actual properties of the iron employed, hysteresis effects, etc., which are slightly at variance with the assumed properties. Experimental refinement is employed to obtain the desired precision
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Thiruvenkadam, S.; Sakthi, P.; Prabhakaran, S.; Chakravarty, Sujay; Ganesan, V.; Rajesh, A. Leo
2018-06-01
Thin film of ternary Cu2SnS3 (CTS), a potential absorber layer for solar cells was successfully deposited by chemical spray pyrolysis technique. The GIXRD pattern revealed that the film having tetragonal Cu2SnS3 phase with the preferential orientation along (112), (200), (220) and (312) plane and it is further confirmed using Raman spectroscopy by the existence of Raman peak at 320 cm-1. Atomic Force Microscopy (AFM) was used to estimate the surface roughness of 28.8 nm. The absorption coefficient was found to be greater than the order of 105 cm-1 and bandgap of 1.70 eV. Hall effect measurement indicates the p type nature of the film with a hole concentration of 1.03 × 1016cm-3 and a hall mobility of 404 cm2/V. The properties of CTS thin film confirmed suitable to be a potential absorber layer material for photovoltaic applications.
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SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques
Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.
2016-05-01
The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.
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Directory of Open Access Journals (Sweden)
Hong J.H.
2015-06-01
Full Text Available With the increasing demand for efficient and economic energy storage, tin disulfide (SnS2, as one of the most attractive anode candidates for the next generation high-energy rechargeable Li-ion battery, have been paid more and more attention because of its high theoretical energy density and cost effectiveness. In this study, a new, simple and effective process, mechanical alloying (MA, has been developed for preparing fine anode material tin disulfides, in which ammonium chloride (AC, referred to as process control agents (PCAs, were used to prevent excessive cold-welding and accelerate the synthesis rates to some extent. Meanwhile, in order to decrease the mean size of SnS2 powder particles and improve the contact areas between the active materials, wet milling process was also conducted with normal hexane (NH as a solvent PCA. The prepared powders were both characterized by X-ray diffraction, Field emission-scanning electron microscopeand particle size analyzer. Finally, electrochemical measurements for Li/SnS2 cells were takenat room temperature, using a two-electrode cell assembled in an argon-filled glove box and the electrolyte of 1M LiPF6 in a mixture of ethylene carbonate(EC/dimethylcarbonate (DMC/ethylene methyl carbonate (EMC (volume ratio of 1:1:1.
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Reghima, Meriem; Akkari, Anis; Guasch, Cathy; Turki-Kamoun, Najoua
2014-09-01
SnS thin films were initially coated onto Pyrex substrates by the chemical bath deposition (CBD) method and annealed at various temperatures ranging from 200°C to 600°C for 30 min in nitrogen gas. X-ray diffraction (XRD) analysis revealed that a structural transition from face-centered cubic to orthorhombic occurs when the annealing temperature is over 500°C. The surface morphology of all thin layers was investigated by means of scanning electron microscopy and atomic force microscopy. The elemental composition of Sn and S, as measured by energy dispersive spectroscopy, is near the stoichiometric ratio. Optical properties studied by means of transmission and reflection measurements show an increase in the absorption coefficient with increasing annealing temperatures. The band gap energy is close to 1.5 eV, which corresponds to the optimum for photovoltaic applications. Last, the thermally stimulated current measurements show that the electrically active traps located in the band gap disappear after annealing at 500°C. These results suggest that, once again, annealing as a post-deposition treatment may be useful for improving the physical properties of the SnS layers included in photovoltaic applications. Moreover, the thermo-stimulated current method may be of practical relevance to explore the electronic properties of more conventional industrial methods, such as sputtering and chemical vapor deposition.
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Chang, Ren-Jie; Tan, Haijie; Wang, Xiaochen; Porter, Benjamin; Chen, Tongxin; Sheng, Yuewen; Zhou, Yingqiu; Huang, Hefu; Bhaskaran, Harish; Warner, Jamie H
2018-04-18
Tin disulfide crystals with layered two-dimensional (2D) sheets are grown by chemical vapor deposition using a novel precursor approach and integrated into all 2D transistors with graphene (Gr) electrodes. The Gr:SnS 2 :Gr transistors exhibit excellent photodetector response with high detectivity and photoresponsivity. We show that the response of the all 2D photodetectors depends upon charge trapping at the interface and the Schottky barrier modulation. The thickness-dependent SnS 2 measurements in devices reveal a transition from the interface-dominated response for thin crystals to bulklike response for the thicker SnS 2 crystals, showing the sensitivity of devices fabricated using layered materials on the number of layers. These results show that SnS 2 has photosensing performance when combined with Gr electrodes that is comparable to other 2D transition metal dichalcogenides of MoS 2 and WS 2 .
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Andreev reflexion studies on planar hybrid SNS-junctions based on 122-thin films
Energy Technology Data Exchange (ETDEWEB)
Doering, Sebastian; Schmidt, Stefan; Schmidl, Frank; Tympel, Volker; Seidel, Paul [Friedrich-Schiller-Universitaet Jena, Institut fuer Festkoerperphysik, Helmholtzweg 5, Jena (Germany); Haindl, Silvia; Kurth, Fritz; Iida, Kazumasa; Holzapfel, Bernhard [IFW Dresden, Institut fuer Metallische Werkstoffe, 01069 Dresden (Germany)
2012-07-01
To investigate the properties of iron-based superconductors, we prepared hybrid junctions in thin film technique. Therefore two geometries were prepared, a planar SNS-junction and an edge junction. The base electrode was made of Ba(Fe{sub 0.9}Co{sub 0.1}){sub 2}As{sub 2} thin films, a sputtered gold layer acts as normal barrier for the planar junction and for the counter electrode we used the conventional superconductor lead. We measured the electrical properties of each electrode, as well as the junctions itself. To obtain information about the order parameter symmetry, we show the differential conductance and compare with different variations of an extended BTK-model. We show differences and commonalities between the results of both junction geometries.
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Yang, Tiefeng; Zheng, Biyuan; Wang, Zhen; Xu, Tao; Pan, Chen; Zou, Juan; Zhang, Xuehong; Qi, Zhaoyang; Liu, Hongjun; Feng, Yexin; Hu, Weida; Miao, Feng; Sun, Litao; Duan, Xiangfeng; Pan, Anlian
2017-12-04
High-quality two-dimensional atomic layered p-n heterostructures are essential for high-performance integrated optoelectronics. The studies to date have been largely limited to exfoliated and restacked flakes, and the controlled growth of such heterostructures remains a significant challenge. Here we report the direct van der Waals epitaxial growth of large-scale WSe 2 /SnS 2 vertical bilayer p-n junctions on SiO 2 /Si substrates, with the lateral sizes reaching up to millimeter scale. Multi-electrode field-effect transistors have been integrated on a single heterostructure bilayer. Electrical transport measurements indicate that the field-effect transistors of the junction show an ultra-low off-state leakage current of 10 -14 A and a highest on-off ratio of up to 10 7 . Optoelectronic characterizations show prominent photoresponse, with a fast response time of 500 μs, faster than all the directly grown vertical 2D heterostructures. The direct growth of high-quality van der Waals junctions marks an important step toward high-performance integrated optoelectronic devices and systems.
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The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance
International Nuclear Information System (INIS)
Cheraghizade, Mohsen; Jamali-Sheini, Farid; Yousefi, Ramin; Niknia, Farhad; Mahmoudian, Mohammad Reza; Sookhakian, Mehran
2017-01-01
In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn_2S_3, and hexagonal phase of SnS_2. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.
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International Nuclear Information System (INIS)
Wei, Renjie; Zhou, Tengfei; Hu, Juncheng; Li, Jinlin
2014-01-01
L-Glutatione (GSH) modified ultrathin SnS 2 nanosheets were successfully synthesized via a one-pot, facile and rapid solvothermal approach. During the process, the GSH not only served as the sulfur sources, the structure-directing agent, but also as the surface modified ligands. The as-synthesized samples mainly consist of ultrathin nanosheets with the thickness of about 10 nm. Inspiringly, even under the visible light (λ > 420 nm) irradiation, the as-synthesized products exhibited highly photocatalytic activities for both the degradation of methyl orange (MO) and the reductive conversion of Cr (VI) in aqueous solution. The superior performance was presented by completely removed the methyl orange and aqueous Cr(VI) in 20 min and 60 min, respectively. It was much higher than the pure samples, which suggested that these obtained photocatalysts have the potential for wastewater treatment in a green way. The high-efficiency of photocatalytic properties could attribute to the ultrathin size of the photocatalysts and the chelation between GSH and Sn (IV), which have the advantages of electron–hole pairs separation. Moreover, modified organic compounds with common electron donors would also enhance the spectral response even to the near infrared region through ligand-to-metal charge transfer (LMCT) mechanism. (papers)
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LS1 Report: A stubborn cavity will soon be replaced
Katarina Anthony
2013-01-01
Testing on the LHC’s replacement RF cryomodule was completed last week in SM18. This module will bring them all to design-level, replacing a faulty cavity that has been acting up since the machine’s start-up. A LHC cryomodule undergoes testing in SM18. Distributed between four cryomodules, the LHC is home to a total of 16 radiofrequency (RF) cavities. Each is designed to provide a 2 MV accelerating field… and all but one has been succeeding at this job. Ever since the machine’s startup, one stubborn cavity in a Point 4 module has quenched whenever it had to stay at 2 MV. The accelerator team found that no amount of conditioning could get the cavity to behave, and the highest continuous wave voltage it could perform at was 1.3 MV. “This was fine for physics,” says Pierre Maesen, who is leading the repair and replacement of the LHC’s cryomodules. “We were able to compensate for this ‘missing’...
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RIA Superconducting Drift Tube Linac R and D
International Nuclear Information System (INIS)
Popielarski, J.; Bierwagen, J.; Bricker, S.; Compton, C.; DeLauter, J.; Glennon, P.; Grimm, T.; Hartung, W.; Harvell, D.; Hodek, M.; Johnson, M.; Marti, F.; Miller, P.; Moblo, A.; Norton, D.; Popielarski, L.; Wlodarczak, J.; York, R.C.; Zeller, A.
2009-01-01
Cavity and cryomodule development work for a superconducting ion linac has been underway for several years at the National Superconducting Cyclotron Laboratory. The original application of the work was the proposed Rare Isotope Accelerator. At present, the work is being continued for use with the Facility for Rare Isotope Beams (FRIB). The baseline linac for FRIB requires 4 types of superconducting cavities to cover the velocity range needed to accelerate an ion beam to (ge) 200 MeV/u: 2 types of quarter-wave resonator (QWR) and 2 types of half-wave resonator (HWR). Superconducting solenoids are used for focusing. Active and passive shielding is required to ensure that the solenoids field does not degrade the cavity performance. First prototypes of both QWR types and one HWR type have been fabricated and tested. A prototype solenoid has been procured and tested. A test cryomodule has been fabricated and tested. The test cryomodule contains one QWR, one HWR, one solenoid, and one super-ferric quadrupole. This report covers the design, fabrication, and testing of this cryomodule
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Spray pyrolyzed Cu2SnS3 thin films for photovoltaic application
Patel, Biren; Waldiya, Manmohansingh; Pati, Ranjan K.; Mukhopadhyay, Indrajit; Ray, Abhijit
2018-05-01
We report the fabrication of Cu2SnS3 (CTS) thin films by a non-vacuum and low cost spray pyrolysis technique. Annealing of the as-deposited film in the sulphur atmosphere produces highly stoichiometric, granular and crystalline CTS phase. The CTS thin films shows direct optical band gap of 1.58 eV with high absorption coefficient of 105 cm-1. Hall measurement shows the carrier concentration of the order of 1021 cm-3 and a favourable resistivity of 10-3 Ω cm. A solar cell architecture of Glass/FTO/CTS/CdS/Al:ZnO/Al was fabricated and its current-voltage characteristic shows an open circuit voltage, short circuit current density and fill-factor of 12.6 mV, 20.2 µA/cm2 and 26% respectively. A further improvement in the solar cell parameters is underway.
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Neutron scattering for studies of soft matter at SNS and HFIR
International Nuclear Information System (INIS)
Smith, Gregory S.
2013-01-01
In this talk, we will present an overview of the scientific program of the Structure and Dynamics of Soft Matter Group, in the Biology and Soft Matter Division of the Neutron Sciences Directorate. From the broader area of soft materials research, the group members have chosen four main areas of scientific focus including: Confinement and Low-Dimensional Systems, Structure and Dynamics of Colloids, Nanoparticle-Polymer Composites, Transport in Membranes, and New Neutron Techniques for soft matter science. We will present several examples of neutron scattering experimental studies in each of these areas highlighting the experimental and theoretical (or modeling) capabilities of the group at both HFIR and SNS. Example topics to be discussed include SANS, reflectometry, and/or quasielastic studies of membranes on patterned interfaces, dynamics and structure of soft colloidal materials (including both polymeric dendrimers and biomimetic materials), gas confinement in mesoporous structures, transport in polyelectrolyte thin films, and development of spin-echo SANS concepts. (author)
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Treatment Of Mercury Target Off-Gas At SNS
International Nuclear Information System (INIS)
DeVore, Joe R.; Freeman, David W.
2007-01-01
The Spallation Neutron Source (SNS) is the first operational spallation source to use liquid Mercury as a target material. This paper describes the treatment system to remove volatile spallation products from a Helium purge stream that emanates from the Mercury target and adjustments made to achieve design goals in response to phenomena experienced during initial operations. The Helium stream is treated to remove volatile spallation products prior to environmental release because of its activity level as these accumulate in the gas space in the Mercury Loop. Unanticipated local dose rates were noted in treatment system components during low power startup. Gamma scanning of these components identified the presence of nineteen noble gas isotopes and their daughters, indicating that the doses resulted from noble gas sorption. Treatment of this equipment with stable Xenon greatly reduced but did not eliminate these. Significant moisture was also encountered in the system, resulting in the plugging of the system cold trap. Changes to some of the system equipment were required together with moisture elimination from components to which moisture was sorbed. Necessary re-configuration of Mercury pump components presented additional requirements and system control changes to accommodate system operation at reduced pressure. The Off-Gas Treatment System has been successfully operated since April, 2006. System availability and removal effectiveness have been high. Operational issues occurring during the first year of operation have been resolved.
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Anaïs Schaeffer
2012-01-01
The cryogenic line, which has been supplying liquid helium to the SM18 Hall area dedicated for tests on radiofrequency cavities and cryomodules for the past 20 years, is currently being dismantled. It will soon be replaced with a state-of-the-art infrastructure with an up to 10 times enhanced performance. Performing preliminary assembly works on the new cryogenic infrastructure in SM18. Part of the SM18 Hall is devoted to tests on radiofrequency (RF) cavities and cryomodules used for beam acceleration in various CERN experiments and accelerators. Inserted into cryostats and cooled to cryogenic temperatures, these cavities are tested at extreme conditions, which reflect their operating environment. The existing cryogenic infrastructure supplying liquid helium to the six RF tests stations – four vertical cryostats and two bunkers for the horizontal cryomodules – hasn’t quite been delivering the goods. Of the 25 g/s of liquid helium that the cryogenic tank was a...
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SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K
Energy Technology Data Exchange (ETDEWEB)
Degraff, Brian D. [ORNL; Howell, Matthew P. [ORNL; Kim, Sang-Ho [ORNL; Neustadt, Thomas S. [ORNL
2017-07-01
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinney pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.
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SNS Cryogenic Test Facility Kinney Vacuum Pump Commissioning and Operation at 2 K
DeGraff, B.; Howell, M.; Kim, S.; Neustadt, T.
2017-12-01
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) has built and commissioned an independent Cryogenic Test Facility (CTF) in support of testing in the Radio-frequency Test Facility (RFTF). Superconducting Radio-frequency Cavity (SRF) testing was initially conducted with the CTF cold box at 4.5 K. A Kinney vacuum pump skid consisting of a roots blower with a liquid ring backing pump was recently added to the CTF system to provide testing capabilities at 2 K. System design, pump refurbishment and installation of the Kinney pump will be presented. During the commissioning and initial testing period with the Kinney pump, several barriers to achieve reliable operation were experienced. Details of these lessons learned and improvements to skid operations will be presented. Pump capacity data will also be presented.
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Baum, Haley
2017-01-01
The purpose of this explanatory sequential mixed methods study was to explore college students' use of social networking services (SNS); examining how and why they communicate about campus safety information. This study took place at Stockton University, a regional state institution in NJ. Undergraduate students took part in an online quantitative…
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Possible use of the SNS synchrotron for feasibility tests on aspects of heavy ion fusion drivers
International Nuclear Information System (INIS)
Planner, C.W.; Rees, G.H.
1980-07-01
There remain a large number of theoretical and practical problems to be solved before a complete accelerator-driver system prototype and a target chamber prototype may be built with any confidence to allow an assessment to be made of the practicality of heavy ion fusion power plants. Two accelerator-driver systems remain under serious consideration for 1 - 10 MJ systems of ion kinetic energies approximately 10 GeV, namely, the induction linac and the storage ring systems. The possible use of the SNS synchrotron for comparative studies of these alternative accelerator-driver systems is discussed. (U.K.)
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Recent progress in the superconducting RF Program at TRIUMF/ISAC
Energy Technology Data Exchange (ETDEWEB)
Laxdal, R.E. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada)]. E-mail: lax@triumf.ca; Fong, K. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada); Laverty, M. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada); Mitra, A. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada); Poirier, R. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada); Sekachev, I. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada); Zvyagintsev, V. [University of British Columbia, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, V6T2A3 (Canada)
2006-07-15
A heavy ion superconducting linac is being installed at TRIUMF to increase the final energy of radioactive beams from ISAC. A first stage of 20 MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being installed with commissioning scheduled for December 2005. The cavities have been fully characterized for rf performance. Two cryomodules have been tested at cold temperatures. A high beta cavity ({beta} {sub 0} = 0.104) for the next phase is presently in design. A weak phase lock loop technique is used to monitor the control loop phase noise to characterize system microphonics. A recent highlight is the acceleration of heavy ions by one cryomodule as a proof of system integrity. The report will summarize all aspects of the program.
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Performance Tests of a Short Faraday Cup Designed for HIE-ISOLDE
Cantero, E; Bravin, E; Fraser, M; Lanaia, D; Sosa, A; Voulot, D
2013-01-01
The On-Line Isotope Mass Separator (ISOLDE) facility at CERN is being upgraded in order to deliver higher energy and intensity radioactive beams. The final setup will consist in replacing the energy variable part of the normal conducting REX post-accelerator with superconducting cavities. In order to preserve the beam emittance, the drift space between the cryomodules housing these cavities has been kept to a minimum. As a consequence, the longitudinal space available for beam diagnostics is severely limited in the inter-cryomodule regions. A Faraday cup (FC) will be installed to measure beam currents, and due to the tight spatial constraints, its length is much smaller than usual. This poses a great challenge when trying to avoid the escape of ion-induced secondary electrons, which would falsify the current measurement. Two prototypes of such a short FC have therefore been tested at REX-ISOLDE using several beam intensities and energies, with the aim of determining its accuracy. In this paper the experimenta...
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A Cross-cultural Qualitative Examination of Social-networking Sites and Academic Performance
Ozer, Ipek; Karpinski, Aryn; Kirschner, Paul A.
2018-01-01
Social-networking site (SNS) use, specifically Facebook®, has remained a controversial subject for many educators and media. Recent studies discuss the negative and positive impacts of SNSs on students’ academic performance. This qualitative study examines the impact of SNSs on students’ academic
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Results of the SNS front end commissioning at Berkeley Lab
International Nuclear Information System (INIS)
Ratti, A.; Ayers, J.J.; Doolittle, L.; Greer, J.B.; Keller, R.; Lewis, S.; Lionberger, C.; Monroy, M.; Pruyn, J.; Staples, J.W.; Syversrude, D.; Thomae, R.; Virostek, S.; Aleksandrov, A.; Shea, T.; SNS Accelerator Physics Group; SNS Beam Diagnostics Collaboration
2002-01-01
The Front-End Systems (FES) for the Spallation Neutron Source (SNS) project comprise an rf-driven H - ion source, an electrostatic 2-lens LEBT, a 2.5 MeV RFQ, followed by a 14-quadrupole, 4-rebuncher MEBT including traveling-wave fast choppers. The nominal 2.5 MeV H - beam has a current of 38 mA at a repetition rate of 60 Hz and 1 ms pulse length, for a macro duty-factor of 6%, and is chopped at a rate of approximately 1 MHz with a mini duty-factor of 68%. The normalized rms beam emittance at the MEBT exit, matching the first tank of a 402.5 MHz Alvarez linac, is measured to be approximately 0.3 π mm mrad. Diagnostic elements include wire scanners, BPMs, fast current monitors, a slit-harp emittance device and RFQ field monitoring probes. The results of the beam commissioning and the operation of the RFQ and diagnostic instrumentation are reported. The entire FES was shut down at LBNL at the end of May 2002 and will be recommissioned at ORNL prior to installation of the drift-tube linac
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International Nuclear Information System (INIS)
Jang, Gyoung Gug; Datskos, Panos G; Jacobs, Christopher B; Ivanov, Ilia N; Joshi, Pooran C; Meyer, Harry M III; Armstrong, Beth L; Kidder, Michelle; Graham, David E; Moon, Ji-Won
2015-01-01
Metal monochalcogenide quantum dot nanocrystals of ZnS, CdS and SnS were prepared by anaerobic, metal-reducing bacteria using in situ capping by oleic acid or oleylamine. The capping agent preferentially adsorbs on the surface of the nanocrystal, suppressing the growth process in the early stages, thus leading to production of nanocrystals with a diameter of less than 5 nm. (paper)
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Magnetic Field Monitoring in the SNS and LANL Neutron EDM Experiments
Aleksandrova, Alina; SNS nEDM Collaboration; LANL nEDM Collaboration
2017-09-01
The SNS neutron EDM experiment requires the ability to precisely control and monitor the magnetic field inside of the fiducial volume. However, it is not always practical (or even possible) to measure the field within the region of interest directly. To remedy this issue, we have designed a field monitoring system that will allow us to reconstruct the field inside of the fiducial volume using noninvasive measurements of the field components at discrete locations external to this volume. A prototype probe array (consisting of 12 single-axis fluxgate magnetometer sensors) was used to monitor the magnetic field within the fiducial volume of an in-house magnetic testing apparatus. In this talk, the design and results of this test will be presented, and the possible implementation of this field monitoring method may have in the room temperature LANL neutron EDM experiment will be discussed. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC-0014622.
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Energy Technology Data Exchange (ETDEWEB)
Sah, Sanjay [Virginia Commonwealth Univ., Richmond, VA (United States)
2016-05-31
Particle accelerators produce beams of high-energy particles, which are used for both fundamental and applied scientific research and are critical to the development of accelerator driven sub-critical reactor systems. An effective magnetic shield is very important to achieve higher quality factor (Qo) of the cryomodule of a particle accelerator. The allowed value of field inside the cavity due to all external fields (particularly the Earth’s magnetic field) is ~15 mG or less. The goal of this PhD dissertation is to comprehensively study the magnetic properties of commonly used magnetic shielding materials at both cryogenic and room temperatures. This knowledge can be used for the enhanced design of magnetic shields of cryomodes (CM) in particle accelerators. To this end, we first studied the temperature dependent magnetization behavior (M-H curves) of Amumetal and A4K under different annealing and deformation conditions. This characterized the effect of stress or deformation induced during the manufacturing processes and subsequent restoration of high permeability with appropriate heat treatment. Next, an energy based stochastic model for temperature dependent anhysteretic magnetization behavior of ferromagnetic materials was proposed and benchmarked against experimental data. We show that this model is able to simulate and explain the magnetic behavior of as rolled, deformed and annealed amumetal and A4K over a large range of temperatures. The experimental results for permeability are then used in a finite element model (FEM) in COMSOL to evaluate the shielding effectiveness of multiple shield designs at room temperature as well as cryogenic temperature. This work could serve as a guideline for future design, development and fabrication of magnetic shields of CMs.
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International Nuclear Information System (INIS)
Bordallo, H.N.; Herwig, K.W.
2001-01-01
Using the Monte-Carlo simulation program McStas, we present the design principles of the proposed high-resolution inverse geometry spectrometer on the SNS-Long Wavelength Target Station (LWTS). The LWTS will provide the high flux of long wavelength neutrons at the requisite pulse rate required by the spectrometer design. The resolution of this spectrometer lies between that routinely achieved by spin echo techniques and the design goal of the high power target station backscattering spectrometer. Covering this niche in energy resolution will allow systematic studies over the large dynamic range required by many disciplines, such as protein dynamics. (author)
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Pivi, M T
2003-01-01
For the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and for the Proton Storage Ring (PSR) at Los Alamos, both with intense and very long bunches, the electron cloud develops primarily by the mechanism of trailing-edge multipacting. We show, by means of simulations for the PSR, how the resonant nature of this mechanism may be effectively broken by tailoring the longitudinal bunch profile at fixed bunch charge, resulting in a significant decrease in the electron-cloud effect. We briefly discuss the experimental difficulties expected in the implementation of this cure.
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International Nuclear Information System (INIS)
Pivi, Mauro T F
2003-01-01
For the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and for the Proton Storage Ring (PSR) at Los Alamos, both with intense and very long bunches, the electron cloud develops primarily by the mechanism of trailing-edge multipacting. We show, by means of simulations for the PSR, how the resonant nature of this mechanism may be effectively broken by tailoring the longitudinal bunch profile at fixed bunch charge, resulting in a significant decrease in the electron-cloud effect. We briefly discuss the experimental difficulties expected in the implementation of this cure
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SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature
Rimmer, Robert; Preble, Joseph P; Reece, Charles E
2005-01-01
In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maint...
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International Nuclear Information System (INIS)
Rehm, C.
2001-01-01
Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror (SM) neutron guides with very high critical angles for total reflection. In this contribution, they discuss how the performance of modern neutron scattering instruments depends on the efficiency of these supermirrors. They outline ideas for enhancing the performance of the SM coatings, particularly for improving the reflectivity at the position of the critical wave vector transfer. A simulation program has been developed which allows different approaches for SM designs to be studied. Possible instrument performance gains are calculated for the example of the SNS reflectometer
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Superconducting Prototype Cavities for the Spallation Neutron Source (SNS) Project
International Nuclear Information System (INIS)
Ciovati, G.; Kneisel, P.; Brawley, J.; Bundy, R.; Campisi, I.; Davis, K.; Macha, K.; Machie, D.; Mammosser, J.; Morgan, S.; Sundelin, R.; Turlington, L.; Wilson, K.; Doleans, M.; Kim, S.H.; Barni, D.; Pagani, C.; Pierini, P.; Matsumoto, K.; Mitchell, R.; Schrage, D.; Parodi, R.; Sekutowicz, J.; Ylae-Oijala, P.
2001-01-01
The Spallation Neutron Source project includes a superconducting linac section in the energy range from 192 MeV to 1000 MeV, operating at a frequency of 805 MHz at 2.1 K. For this energy range two types of cavities are needed with geometrical beta - values of beta= 0.61 and beta= 0.81. An aggressive cavity prototyping program is being pursued at Jlab, which calls for fabricating and testing of four beta= 0.61 cavities and two beta= 0.81 cavities. Both types consist of six cells made from high purity niobium and feature one HOM coupler on each beam pipe and a port for a high power coaxial input coupler. Three of the four beta= 0.61 cavities will be used for a cryomodule test in early 2002. At this time four medium beta cavities and one high beta cavity have been completed at JLab. The first tests on the beta=0.61 cavity and the beta= 0.81 exceeded the design values for gradient and Q - value: E acc = 1 0.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.61 and E acc = 12.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.81. One of the medium beta cavities has been equipped with an integrated helium vessel and measurements of the static and dynamic Lorentz force detuning will be done and compared to the ''bare'' cavities. In addition two single cell cavities have been fabricated, equipped with welded-on HOM couplers. They are being used to evaluate the HOM couplers with respect to multipacting, fundamental mode rejection and HOM damping as far as possible in a single cell. This paper will describe the cavity design with respect to electrical and mechanical features, the fabrication efforts and the results obtained with the different cavities existing at the time of this workshop
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Energy Technology Data Exchange (ETDEWEB)
Sazideh, M.R., E-mail: Mohammadrezasazideh@gmail.com [Thin Film Lab., Faculty of Physics, Semnan University, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Dizaji, H. Rezagholipour, E-mail: hrgholipour@semnan.ac.ir [Faculty of Physics, Semnan University, P.O. Box: 35195-363, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Ehsani, M.H., E-mail: mhe_ehsani@yahoo.com [Faculty of Physics, Semnan University, P.O. Box: 35195-363, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of); Moghadam, R. Zarei, E-mail: r.zarei1991@gmail.com [Thin Film Lab., Faculty of Physics, Semnan University, Semnan, Islamic Republic of Iran (Iran, Islamic Republic of)
2017-05-31
Highlights: • SnS thin films produced by thermal evaporation method using glancing angle deposition technique. • At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range. • FESEM images showed drastic changes in the structure and morphology of individual nano-plates as a function of incident angle deposition. - Abstract: Tin sulfide (SnS) films were prepared by thermal evaporation method using Glancing Angle Deposition (GLAD) technique at zero and different oblique incident flux angles (α = 45°, 55°, 65°, 75° and 85°). The physical properties of prepared films were systematically investigated. The X-ray diffraction analysis indicated that the film deposited at α = 0° formed as single phase with an orthorhombic structure. However, the layers became amorphous at α = 45°, 55°, 65°, 75° and 85°. Beside the appearance of amorphous feature in the film prepared at α higher than zero, Sn{sub 2}S{sub 3} phase was also observed. The top and cross-sectional field emission scanning electron microscope (FESEM) images of the samples showed noticeable changes in the structure and morphology of individual nano-plates as a function of incident angle. The band gap and refractive index values of the films were calculated by optical transmission measurements. The optical band-gap values were observed to increase with increasing the incident flux angle. This can be due to presence of Sn{sub 2}S{sub 3} phase observed in the samples produced at α values other than zero. The effective refractive index and porosity exhibit an opposite evolution as the incident angle α rises. At α = 85° the layers show a considerable change in effective refractive index (Δn = 1.7) at near-IR spectral range.
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Energy Technology Data Exchange (ETDEWEB)
Bandholtz, T.
2003-05-01
Encouraged by the success of the thesaurus-based automatic indexing of environmental information provided by the German Environmental Information Network (gein {sup trademark}, http://www.gein.de), the terminology collections of gein {sup trademark} have been integrated and cross-networked in a comprehensive Topic Map. On this base, the text analysis module could be considerably enhanced. Any access to the terminology and its methods has been provided by means of Web Services. gein {sup trademark} (starting with version 2003) incorporates these Web Services in the productive installation. Besides that, SNS provides basic functionality for terminology editors. (orig.)
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Mesoporous carbon anchored with SnS2 nanosheets as an advanced anode for lithium-ion batteries
International Nuclear Information System (INIS)
Li, Jianping; Wu, Ping; Lou, Feijian; Zhang, Peng; Tang, Yawen; Zhou, Yiming; Lu, Tianhong
2013-01-01
Highlights: •SnS 2 nanosheets densely and uniformly anchored on 3D mesoporous carbon matrix. •Unique structural characteristics of both 2D nanosheet and 3D porous carbon matrix. •Markedly enhanced lithium storage capability by virtue of its structure superiority. -- Abstract: This paper reports a novel type of nanohybrid, mesoporous carbon anchored with SnS 2 nanosheets (MC-SnS 2 NSs), which integrates the structural characteristics of both two-dimensional (2D) nanosheet and 3D porous carbon matrix. When evaluated as an anode for lithium-ion batteries, the MC-SnS 2 NSs exhibits significantly enhanced cycling stability and rate capability by virtue of its unique structural superiority
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The SNS/HFIR Web Portal System - How Can it Help Me?
Energy Technology Data Exchange (ETDEWEB)
Miller, Stephen D; Geist, Al; Herwig, Kenneth W; Peterson, Peter F; Reuter, Michael A; Ren, Shelly; Bilheux, Jean-Christophe; Campbell, Stuart I; Kohl, James A; Vazhkudai, Sudharshan S; Cobb, John W; Lynch, Vickie E; Chen Meili; Trater, James R; Smith, Bradford C; Swain, Tom; Huang Jian [University of Tennessee, Knoxville, TN (United States); Mikkelson, Ruth; Mikkelson, Dennis, E-mail: millersd@ornl.gov
2010-11-01
In a busy world, continuing with the status-quo, to do things the way we are already familiar, often seems to be the most efficient way to conduct our work. We look for the value-add to decide if investing in a new method is worth the effort. How shall we evaluate if we have reached this tipping point for change? For contemporary researchers, understanding the properties of the data is a good starting point. The new generation of neutron scattering instruments being built are higher resolution and produce one or more orders of magnitude larger data than the previous generation of instruments. For instance, we have grown out of being able to perform some important tasks with our laptops - the data are too big and the computations would simply take too long. These large datasets can be problematic as facility users now begin to grapple with many of the same issues faced by more established computing communities. These issues include data access, management, and movement, data format standards, distributed computing, and collaboration among others. The Neutron Science Portal has been architected, designed, and implemented to provide users with an easy-to-use interface for managing and processing data, while also keeping an eye on meeting modern cybersecurity requirements imposed on institutions. The cost of entry for users has been lowered by utilizing a web interface providing access to backend portal resources. Users can browse or search for data which they are allowed to see, data reduction applications can be run without having to load the software, sample activation calculations can be performed for SNS and HFIR beamlines, McStas simulations can be run on TeraGrid and ORNL computers, and advanced analysis applications such as those being produced by the DANSE project can be run. Behind the scenes is a 'live cataloging' system which automatically catalogs and archives experiment data via the data management system, and provides proposal team members
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The SNS/HFIR Web Portal System - How Can it Help Me?
International Nuclear Information System (INIS)
Miller, Stephen D; Geist, Al; Herwig, Kenneth W; Peterson, Peter F; Reuter, Michael A; Ren, Shelly; Bilheux, Jean-Christophe; Campbell, Stuart I; Kohl, James A; Vazhkudai, Sudharshan S; Cobb, John W; Lynch, Vickie E; Chen Meili; Trater, James R; Smith, Bradford C; Swain, Tom; Huang Jian; Mikkelson, Ruth; Mikkelson, Dennis
2010-01-01
In a busy world, continuing with the status-quo, to do things the way we are already familiar, often seems to be the most efficient way to conduct our work. We look for the value-add to decide if investing in a new method is worth the effort. How shall we evaluate if we have reached this tipping point for change? For contemporary researchers, understanding the properties of the data is a good starting point. The new generation of neutron scattering instruments being built are higher resolution and produce one or more orders of magnitude larger data than the previous generation of instruments. For instance, we have grown out of being able to perform some important tasks with our laptops - the data are too big and the computations would simply take too long. These large datasets can be problematic as facility users now begin to grapple with many of the same issues faced by more established computing communities. These issues include data access, management, and movement, data format standards, distributed computing, and collaboration among others. The Neutron Science Portal has been architected, designed, and implemented to provide users with an easy-to-use interface for managing and processing data, while also keeping an eye on meeting modern cybersecurity requirements imposed on institutions. The cost of entry for users has been lowered by utilizing a web interface providing access to backend portal resources. Users can browse or search for data which they are allowed to see, data reduction applications can be run without having to load the software, sample activation calculations can be performed for SNS and HFIR beamlines, McStas simulations can be run on TeraGrid and ORNL computers, and advanced analysis applications such as those being produced by the DANSE project can be run. Behind the scenes is a 'live cataloging' system which automatically catalogs and archives experiment data via the data management system, and provides proposal team members access to
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The SNS/HFIR Web Portal System - How Can it Help Me?
Miller, Stephen D.; Geist, Al; Herwig, Kenneth W.; Peterson, Peter F.; Reuter, Michael A.; Ren, Shelly; Bilheux, Jean-Christophe; Campbell, Stuart I.; Kohl, James A.; Vazhkudai, Sudharshan S.; Cobb, John W.; Lynch, Vickie E.; Chen, Meili; Trater, James R.; Smith, Bradford C.; (William Swain, Tom; Huang, Jian; Mikkelson, Ruth; Mikkelson, Dennis; een, Mar K. L. Gr
2010-11-01
In a busy world, continuing with the status-quo, to do things the way we are already familiar, often seems to be the most efficient way to conduct our work. We look for the value-add to decide if investing in a new method is worth the effort. How shall we evaluate if we have reached this tipping point for change? For contemporary researchers, understanding the properties of the data is a good starting point. The new generation of neutron scattering instruments being built are higher resolution and produce one or more orders of magnitude larger data than the previous generation of instruments. For instance, we have grown out of being able to perform some important tasks with our laptops - the data are too big and the computations would simply take too long. These large datasets can be problematic as facility users now begin to grapple with many of the same issues faced by more established computing communities. These issues include data access, management, and movement, data format standards, distributed computing, and collaboration among others. The Neutron Science Portal has been architected, designed, and implemented to provide users with an easy-to-use interface for managing and processing data, while also keeping an eye on meeting modern cybersecurity requirements imposed on institutions. The cost of entry for users has been lowered by utilizing a web interface providing access to backend portal resources. Users can browse or search for data which they are allowed to see, data reduction applications can be run without having to load the software, sample activation calculations can be performed for SNS and HFIR beamlines, McStas simulations can be run on TeraGrid and ORNL computers, and advanced analysis applications such as those being produced by the DANSE project can be run. Behind the scenes is a "live cataloging" system which automatically catalogs and archives experiment data via the data management system, and provides proposal team members access to
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International Nuclear Information System (INIS)
Pivi, M.; Furman, M.A.
2003-01-01
For the storage ring of the Spallation Neutron Source(SNS) at Oak Ridge, and for the Proton Storage Ring (PSR) at Los Alamos, both with intense and very long bunches, the electroncloud develops primarily by the mechanism of trailing-edge multipacting. We show, by means of simulations for the PSR, how the resonant nature of this mechanism may be effectively broken by tailoring the longitudinal bunch profile at fixed bunch charge, resulting in a significant decrease in the electron-cloud effect. We briefly discuss the experimental difficulties expected in the implementation of this cure
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Xie, Mingyuan; Zhang, Tailiang
2018-04-01
Ag3PO4 can-not be widely used as an efficient photocatalyst in practical applications because of its susceptibility to photocorrosion. In this study, a novel, ternary Z-scheme photocatalytic system containing graphene oxide (GO), Ag3PO4 and SnS2 was fabricated by a one-pot, mild, in-situ precipitation method successfully. Using Rhodamine B (RhB) as the target of elimination, GO/Ag3PO4/SnS2 exhibited outstanding photocatalytic and anti-photocorrosion properties compared with those of Ag3PO4, Ag3PO4/SnS2 and GO/Ag3PO4. RhB was thoroughly degraded over the optimized GO/Ag3PO4/SnS2 nanocomposite after only 15 min under visible-light irradiation; this result is approximately 2.14, 3.33 and 5.83 times faster than that of GO/Ag3PO4, Ag3PO4/SnS2 and Ag3PO4, respectively. After three reuses, the photocatalytic activity of the ternary composite slightly decreased but remained 2.36, 4.08 and 12.70 times higher than those of the reused GO/Ag3PO4, Ag3PO4/SnS2 and Ag3PO4, respectively. In this system, the efficient separation and migration of the photoinduced current carriers in Ag3PO4 was realized through a double Z-scheme electron-transfer mechanism in which the GO nanosheets acted as the photocatalyst and electron mediator, thereby enhancing the photoactivity and stability of Ag3PO4. The present study provides a new perspective for enhancing photocatalytic and anti-photocorrosion performances in perishable photocatalysts for organic sewage and other environmental contamination treatments.
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Temperature behavior of SNS-like Nb/Al-AlO x/Nb Josephson junctions
International Nuclear Information System (INIS)
Lacquaniti, V.; Andreone, D.; Maggi, S.; Rocci, R.; Sosso, A.; Steni, R.
2006-01-01
Overdamped Nb/Al-AlO x /Nb Josephson junctions are an intermediate state between the SIS and SNS Josephson junctions. Stable and reproducible non-hysteretic current-voltage characteristics have been obtained with a proper choice of the fabrication parameters, featuring critical current densities J c up to 25 kA/cm 2 and characteristic voltages up to 450 μV. While these values make the junctions interesting for RSFQ electronic circuits, their response to an RF signal at 70 GHz has demonstrated their suitability for both programmable and ac voltage standard. In these work we analyse the temperature behavior of these junctions up to T/T c = 1, T c being the niobium critical temperature, which gives relevant information on the junction structure and, especially, on the oxide insulator/metallic film barrier, which is the key for the reproducible transition from an hysteretic to a non-hysteretic behavior. The results are also compared with other data of hysteretic and overdamped junctions
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ARIEL E-linac Cryogenic System: Commissioning and First Operational Experience
International Nuclear Information System (INIS)
Koveshnikov, A; Bylinskii, I; Hodgson, G; Kishi, D; Laxdal, R; Ma, Y; Nagimov, R; Yosifov, D
2015-01-01
The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. A key part of the ARIEL project is a 10 mA 50 MeV continuous-wave superconducting radiofrequency (SRF) electron linear accelerator (e-linac). The 1.3 GHz SRF cavities are operated at 2 K. HELIAL LL helium liquefier by Air Liquide Advanced Technologies (ALAT) with a tuneable liquid helium (LHe) production was installed and commissioned in Q4’2013 [1]. It provides 4 K liquid helium to one injector and one accelerator cryomodules that were installed and tested in 2014. The 4 K to 2 K liquid helium transition is achieved on-board of each cryomodule. The cryoplant, LHe and LN2 distributions, sub-atmospheric (S/A) system and cryomodules were successfully commissioned and integrated into the e-linac cryogenic system. Required pressure regulation for both 4 K cryoplant in the Dewar and 2 K with the S/A system was achieved under simulated load. Final integration tests confirmed overall stable performance of the cryogenic system with two cryomodules installed. The paper presents details of the cryogenic system commissioning tests as well as highlights of the initial operational experience. (paper)
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CEBAF SRF Performance during Initial 12 GeV Commissioning
International Nuclear Information System (INIS)
Bachimanchi, Ramakrishna; Allison, Trent; Daly, Edward; Drury, Michael; Hovater, J; Lahti, George; Mounts, Clyde; Nelson, Richard; Plawski, Tomasz
2015-09-01
The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of eleven new 100 MV cryomodules (88 cavities). The superconducting RF cavities are designed to operate CW at an accelerating gradient of 19.3 MV/m with a Q L of 3x10 7 . Not all the cavities were operated at the minimum gradient of 19.3 MV/m with the beam. Though the initial 12 GeV milestones were achieved during the initial commissioning of CEBAF, there are still some issues to be addressed for long term reliable operation of these modules. This paper reports the operational experiences during the initial commissioning and the path forward to improve the performance of C100 (100 MV) modules.
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Nolan, Samantha; Hendricks, Joyce; Williamson, Moira; Ferguson, Sally
2018-03-01
This article presents a discussion highlighting the relevance and strengths of using narrative inquiry to explore experiences of social networking site (SNS) use by adolescent mothers. Narrative inquiry as a method reveals truths about holistic human experience. Knowledge gleaned from personal narratives informs nursing knowledge and clinical practice. This approach gives voice to adolescent mothers in relation to their experiences with SNS as a means of providing social support. Discussion paper. This paper draws and reflects on the author's experiences using narrative inquiry and is supported by literature and theory. The following databases were searched: CINAHL, Cochrane Library, Medline, Scopus, ERIC, ProQuest, PsychINFO, Web of Science and Health Collection (Informit). Key terms and Boolean search operators were used to broaden the search criteria. Search terms included: adolescent mother, teenage mother, "social networking sites", online, social media, Facebook, social support, social capital and information. Dates for the search were limited to January 1995-June 2017. Narrative research inherently values the individual "story" of experience. This approach facilitates rapport building and methodological flexibility with an often difficult to engage sample group, adolescents. Narrative inquiry reveals a deep level of insight into social networking site use by adolescent mothers. The flexibility afforded by use of a narrative approach allows for fluidity and reflexivity in the research process. © 2017 John Wiley & Sons Ltd.
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International Nuclear Information System (INIS)
Ludewig, H.; Catalan-Lasheras, N.; Simos, N.; Walker, J.; Mallen, A.; Wei, J.; Todosow, M.
2000-01-01
The highest doses to components in the SNS ring are expected to be to those located in the collimation straight section. In this paper the authors present estimated doses to magnets and cable located between collimators. In addition the buildup of relatively long half-life radioactive isotopes is estimated, following machine operation and shutdown. Finally, the potential dose to operators approaching the machine following operation and shutdown for four hours is made. The results indicate that selected components might require replacement after several years of full power operation. In addition, the reflection of gamma-rays from the tunnel walls contribute a non-negligible amount to the dose of an operator in the tunnel following machine shutdown
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HOM Survey of the First CEBAF Upgrade Style Cavity Pair
International Nuclear Information System (INIS)
Marhauser, Frank; Daly, Edward; Davis, G.; Drury, Michael; Grenoble, Christiana; Hogan, John; Manus, Robert; Preble, Joseph; Reece, Charles; Rimmer, Robert; Tian, Kai; Wang, Haipeng
2009-01-01
The planned upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) at the Thomas Jefferson National Accelerator Laboratory (JLab) requires ten new superconducting rf (SRF) cavity cryomodules to double the beam energy to the envisaged 12 GeV. Adequate cavity Higher Order Mode (HOM) suppression is essential to avoid multipass, multibunch beam break-up (BBU) instabilities of the recirculating beam. We report on detailed HOM surveys performed for the first two upgrade style cavities tested in a dedicated cavity pair cryomodule at 2K. The safety margin to the BBU threshold budget at 12 GeV has been assessed.
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Lee, Soon Li; Kim, Jung-Ae; Golden, Karen Jennifer; Kim, Jae-Hwi; Park, Miriam Sang-Ah
2016-01-01
Perception of the autonomy and relatedness of the self may be influenced by one's experiences and social expectations within a particular cultural setting. The present research examined the role of culture and the Autonomous-Related self-construal in predicting for different aspects of Social Networking Sites (SNS) usage in three Asian countries, especially focusing on those aspects serving interpersonal goals. Participants in this cross-cultural study included 305 university students from Ma...
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System and method for embedding emotion in logic systems
Curtis, Steven A. (Inventor)
2012-01-01
A system, method, and computer readable-media for creating a stable synthetic neural system. The method includes training an intellectual choice-driven synthetic neural system (SNS), training an emotional rule-driven SNS by generating emotions from rules, incorporating the rule-driven SNS into the choice-driven SNS through an evolvable interface, and balancing the emotional SNS and the intellectual SNS to achieve stability in a nontrivial autonomous environment with a Stability Algorithm for Neural Entities (SANE). Generating emotions from rules can include coding the rules into the rule-driven SNS in a self-consistent way. Training the emotional rule-driven SNS can occur during a training stage in parallel with training the choice-driven SNS. The training stage can include a self assessment loop which measures performance characteristics of the rule-driven SNS against core genetic code. The method uses a stability threshold to measure stability of the incorporated rule-driven SNS and choice-driven SNS using SANE.
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Neutronics for the SNS long wavelength target station
International Nuclear Information System (INIS)
Iverson, E.B.; Micklich, B.J.; Carpenter, J.M.
2001-01-01
One of the most significant and adventurous aspects of the LWTS (Long Wavelength Target Station) design concept is the use of slab moderators, historically considered to be awkward due to the high contamination of the neutron beams with fast and high- energy neutrons. Concern over this contamination is the reason behind our proposition that none of the beam on a slab moderator should be viewed directly, that is, without a curved guide, compact bender, or other fast and high-energy neutron filter. We made a large number of calculations concerning fast neutron source term of the solid target-slab moderator configuration with monolithic solid methane, which includes a curved guide or compact beam bender. We also made optimization on target position, beam void open angle, target gap and target division of the split target configuration. All fast and high-energy neutron spectra will be reported as lethargy spectra, normalized to 1 eV. In this way, we will attempt to define the 'cost' of using slab moderators as a function of the payoff gained from their use. We report these data for general information and discussion, and further draw the conclusions. Numerous issues have arisen in the course of the LWTS concept development, which require more information than is now in hand to provide the basis for detailed design and for potential design innovations. Some of the R and D issues are listed, along with proposed efforts to fill design needs. We have devised a highly effective 'base case' conceptual design for LWTS, which we are still evaluating and optimizing. LWTS will provide distinctly unique capabilities complimentary to SNS (Spallation Neutron Source) HPTS (High Power Target Station). The configuration of LWTS is strongly coupled to instrument requirements through close interaction with scientists formulating the science case and instrument suite. (Tanaka, Y.)
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Non-monotonic effect of growth temperature on carrier collection in SnS solar cells
International Nuclear Information System (INIS)
Chakraborty, R.; Steinmann, V.; Mangan, N. M.; Brandt, R. E.; Poindexter, J. R.; Jaramillo, R.; Mailoa, J. P.; Hartman, K.; Polizzotti, A.; Buonassisi, T.; Yang, C.; Gordon, R. G.
2015-01-01
We quantify the effects of growth temperature on material and device properties of thermally evaporated SnS thin-films and test structures. Grain size, Hall mobility, and majority-carrier concentration monotonically increase with growth temperature. However, the charge collection as measured by the long-wavelength contribution to short-circuit current exhibits a non-monotonic behavior: the collection decreases with increased growth temperature from 150 °C to 240 °C and then recovers at 285 °C. Fits to the experimental internal quantum efficiency using an opto-electronic model indicate that the non-monotonic behavior of charge-carrier collection can be explained by a transition from drift- to diffusion-assisted components of carrier collection. The results show a promising increase in the extracted minority-carrier diffusion length at the highest growth temperature of 285 °C. These findings illustrate how coupled mechanisms can affect early stage device development, highlighting the critical role of direct materials property measurements and simulation
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Experimental Results Obtained with Air Liquide Cold Compression System CERN LHC and SNS Projects
Delcayre, F; Hamber, F; Hilbert, B; Monneret, E; Toia, J L
2006-01-01
Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high‐capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC wil...
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Structural and optical properties of Cu2SnS3 thin films obtained by SILAR method
Directory of Open Access Journals (Sweden)
Aykut ASTAM
2017-06-01
Full Text Available Cu2SnS3 thin films were obtained by annealing of SILAR deposited films at 350°C for 1 hour in sulphur atmosphere. The structural and optical properties of the films were investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray analysis (EDAX and optical absorption measurements, before and after annealing. The XRD results showed that the annealing process transformed the crystal structure of the films from amorphous to polycrystalline. SEM images revealed that the surface morphology of films was changed after annealing while EDAX analysis showed that the films were excess in copper concentration before and after annealing. Optical absorption measurements confirmed that the direct band gap of films decreased from 1.27 eV to 1.21 eV with annealing.
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SNS Resonance Control Cooling Systems and Quadrupole Magnet Cooling Systems DIW Chemistry
Energy Technology Data Exchange (ETDEWEB)
Magda, Karoly [ORNL
2018-01-01
This report focuses on control of the water chemistry for the Spallation Neutron Source (SNS) Resonance Control Cooling System (RCCS)/Quadrupole Magnet Cooling System (QMCS) deionized water (DIW) cooling loops. Data collected from spring 2013 through spring 2016 are discussed, and an operations regime is recommended.It was found that the RCCS operates with an average pH of 7.24 for all lines (from 7.0 to 7.5, slightly alkaline), the average low dissolved oxygen is in the area of < 36 ppb, and the main loop average resistivity of is > 14 MΩ-cm. The QMCS was found to be operating in a similar regime, with a slightly alkaline pH of 7.5 , low dissolved oxygen in the area of < 45 ppb, and main loop resistivity of 10 to 15 MΩ-cm. During data reading, operational corrections were done on the polishing loops to improve the water chemistry regime. Therefore some trends changed over time.It is recommended that the cooling loops operate in a regime in which the water has a resistivity that is as high as achievable, a dissolved oxygen concentration that is as low as achievable, and a neutral or slightly alkaline pH.
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Capabilities, performance, and future possibilities of high frequency polyphase resonant converters
International Nuclear Information System (INIS)
Reass, W.A.; Baca, D.M.; Bradley, J.T. III; Hardek, T.W.; Kwon, S.I.; Lynch, M.T.; Rees, D.E.
2004-01-01
High Frequency Polyphase Resonant Power Conditioning (PRPC) techniques developed at Los Alamos National Laboratory (LANL) are now being utilized for the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) accelerator klystron RF amplifier power systems. Three different styles of polyphase resonant converter modulators were developed for the SNS application. The various systems operate up to 140 kV, or 11 MW pulses, or up to 1.1 MW average power, all from a DC input of +/- 1.2 kV. Component improvements realized with the SNS effort coupled with new applied engineering techniques have resulted in dramatic changes in RF power conditioning topology. As an example, the high-voltage transformers are over 100 times smaller and lighter than equivalent 60 Hz versions. With resonant conversion techniques, load protective networks are not required. A shorted load de-tunes the resonance and little power transfer can occur. This provides for power conditioning systems that are inherently self-protective, with automatic fault 'ride-through' capabilities. By altering the Los Alamos design, higher power and CW power conditioning systems can be realized without further demands of the individual component voltage or current capabilities. This has led to designs that can accommodate 30 MW long pulse applications and megawatt class CW systems with high efficiencies. The same PRPC techniques can also be utilized for lower average power systems (∼250 kW). This permits the use of significantly higher frequency conversion techniques that result in extremely compact systems with short pulse (10 to 100 us) capabilities. These lower power PRPC systems may be suitable for medical Linacs and mobile RF systems. This paper will briefly review the performance achieved for the SNS accelerator and examine designs for high efficiency megawatt class CW systems and 30 MW peak power applications. The devices and designs for compact higher frequency converters utilized for short pulse
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Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields
Energy Technology Data Exchange (ETDEWEB)
Morosh, Viacheslav; Kieler, Oliver; Weimann, Thomas; Zorin, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Mueller, Benedikt; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany)
2016-07-01
Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton μ{sub B}) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm x 150 nm, effective loop areas < 0.05 μm{sup 2} and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens μ{sub B}/Hz{sup 1/2} has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.
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Corinne Pralavorio
2015-01-01
The first HIE-ISOLDE cryomodule was commissioned at the end of October. The radioactive ion beams can now be accelerated to 4.3 MeV per nucleon. The ISOLDE beamline that supplies the Miniball array. The first HIE-ISOLDE cryomodule can be seen in the background, in its light-grey cryostat. ISOLDE is getting an energy boost. The first cryomodule of the new superconducting linear accelerator HIE-ISOLDE (High Intensity and Energy ISOLDE), located downstream of the REX-ISOLDE accelerator, increases the energy of the radioactive ion beams from 3 to 4.3 MeV per nucleon. It supplies the Miniball array, where an experiment using radioactive zinc ions (see box) began at the end of October. This is the first stage in the commissioning of HIE-ISOLDE. The facility will ultimately be equipped with four cryomodules that will accelerate the beams to 10 MeV per nucleon. Each cryomodule has five accelerating cavities and a solenoid, which focuses the beam. All of these components are superconducting. This first ...
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Development of a Social DTN for Message Communication between SNS Group Members
Directory of Open Access Journals (Sweden)
Hidenori Takasuka
2018-04-01
Full Text Available Smartphones have the ability to communicate with other terminals through ad hoc connections. A variety of applications have been developed to exploit this ability. The authors have developed an Android OS (operating system application (called “social DTN manager” that builds a DTN (delay, disruption, disconnection tolerant networking among members of a social networking service (SNS community using a community token. The members can exchange messages over this network. Control messages for building a DTN are forwarded to only those nodes that use the same community token in order to reduce flooding of message copies. When a source node sends a communication request to its destination node, they exchange control messages to establish a communication route. Relay nodes use these messages to create and hold routing information for these nodes in their routing tables. Thereafter, relay nodes can forward data messages based on their routing tables. This again reduces flooding of message copies. The social DTN manager incorporates these functions, Facebook Graph API and Google Nearby Connections API. The authors have installed it in Android terminals and confirmed that a social DTN can successfully be built using this application and that data messages can be exchanged between terminals via reactive routes.
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Experimental Results Obtained with Air Liquide Cold Compression System: CERN LHC and SNS Projects
Delcayre, F.; Courty, J.-C.; Hamber, F.; Hilbert, B.; Monneret, E.; Toia, J.-L.
2006-04-01
Large scale collider facilities will make intensive use of superconducting magnets, operating below 2.0 K. This dictates high-capacity refrigeration systems operating below 2.0 K. These systems, making use of cryogenic centrifugal compressors in a series arrangement with room temperature screw compressors will be coupled to a refrigerator, providing a certain power at 4.5 K. A first Air Liquide Cold Compression System (CCS) unit was built and delivered to CERN in 2001. Installed at the beginning of 2002, it was commissioned and tested successfully during year 2002. A series of four sets of identical CCS were then tested in 2004. Another set of four cryogenic centrifugal compressors (CCC) has been delivered to Thomas Jefferson National Accelerator Facility (JLAB) for the Spallation Neutron Source (SNS) in 2002. These compressors were tested and commissioned from December 2004 to July 2005. The experimental results obtained with these systems will be presented and discussed: the characteristics of the CCC will be detailed. The principles of control for the CCC in series will be detailed.
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Eco-friendly p-type Cu2SnS3 thermoelectric material: crystal structure and transport properties
Shen, Yawei; Li, Chao; Huang, Rong; Tian, Ruoming; Ye, Yang; Pan, Lin; Koumoto, Kunihito; Zhang, Ruizhi; Wan, Chunlei; Wang, Yifeng
2016-01-01
As a new eco-friendly thermoelectric material, copper tin sulfide (Cu2SnS3) ceramics were experimentally studied by Zn-doping. Excellent electrical transport properties were obtained by virtue of 3-dimensionally conductive network for holes, which are less affected by the coexistence of cubic and tetragonal phases that formed upon Zn subsitition for Sn; a highest power factors ~0.84 mW m−1 K−2 at 723 K was achieved in the 20% doped sample. Moreover, an ultralow lattice thermal conductivity close to theoretical minimum was observed in these samples, which could be related to the disordering of atoms in the coexisting cubic and tetragonal phases and the interfaces. Thanks to the phonon-glass-electron-crystal features, a maximum ZT ~ 0.58 was obtained at 723 K, which stands among the tops for sulfide thermoelectrics at the same temperature. PMID:27666524
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Photovoltaic performance of hybrid ITO/PEDOT:PSS/n-SnS/Al solar cell structure
Jain, Priyal; Arun, P.
2016-07-01
The present paper discusses the performance of ITO/PEDOT:PSS/n-SnS/Al structured solar cells fabricated by thermal evaporation. The performance characterizing parameters such as the open circuit voltage, short circuit current density, series resistance, parallel resistance, ideality factor and the overall efficiency were found to be dependent on the SnS grain size in the nano-meter regime and incident light intensity. The experimental work directly reconfirms the theoretical results and ideas raised in the literature by early researchers.
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ARIEL e-LINAC: Commissioning and Development
Laxdal, R. E.; Zvyagintsev, V.
2016-09-01
A superconducting electron Linac (e-Linac) will be a part of the ARIEL facility for the production of radioactive ion beams (RIB) at TRIUMF. The e-Linac will consist of five 1.3GHz 9-cell cavities in three cryomodules delivering a 50MeV 10mA beam. The baseline operation will be single pass but a re-circulating ring is planned to allow either energy boost or energy recovery operation. The first stage of the accelerator which consists of two cryomodules has been successfully commissioned in 2014. The paper will discuss the superconducting radio-frequency (SRF) challenges of the accelerator. Cavities, crymodules and RF system design, preparation, and performance will be presented.
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ARIEL e-LINAC: Commissioning and Development
International Nuclear Information System (INIS)
Laxdal, R.E.; Zvyagintsev, V.
2016-01-01
A superconducting electron Linac (e-Linac) will be a part of the ARIEL facility for the production of radioactive ion beams (RIB) at TRIUMF. The e-Linac will consist of five 1.3GHz 9-cell cavities in three cryomodules delivering a 50MeV 10mA beam. The baseline operation will be single pass but a re-circulating ring is planned to allow either energy boost or energy recovery operation. The first stage of the accelerator which consists of two cryomodules has been successfully commissioned in 2014. The paper will discuss the superconducting radio-frequency (SRF) challenges of the accelerator. Cavities, crymodules and RF system design, preparation, and performance will be presented. (paper)
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Directory of Open Access Journals (Sweden)
Zhiguo Wu
2015-01-01
Full Text Available Sn chalcogenides, including SnS, Sn2S3, and SnS2, have been extensively studied as anode materials for lithium batteries. In order to obtain one kind of high capacity, long cycle life lithium batteries anode materials, three-dimensional (3D flower-like hierarchitectures constructed by SnS/SnS2 heterostructure nanosheets with thickness of ~20 nm have been synthesized via a simple one-pot solvothermal method. The obtained samples exhibit excellent electrochemical performance as anode for Li-ion batteries (LIBs, which deliver a first discharge capacity of 1277 mAhg−1 and remain a reversible capacity up to 500 mAhg−1 after 50 cycles at a current of 100 mAg−1.
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SUPERCONDUCTING RADIO-FREQUENCY MODULES TEST FACILITY OPERATING EXPERIENCE
International Nuclear Information System (INIS)
Soyars, W.; Bossert, R.; Darve, C.; Degraff, B.; Klebaner, A.; Martinez, A.; Pei, L.; Theilacker, J.
2008-01-01
Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R and D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service the SRF R and D needs. The project's first stage has been successfully completed, which allows for distribution of cryogens for a single-cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at Meson Detector Building (MDB) results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project
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Effects of deposition period on the chemical bath deposited Cu4SnS4 thin films
International Nuclear Information System (INIS)
Kassim, Anuar; Wee Tee, Tan; Soon Min, Ho.; Nagalingam, Saravanan
2010-01-01
Cu 4 SnS 4 thin films were prepared by simple chemical bath deposition technique. The influence of deposition period on the structural, morphological and optical properties of films was studied. The films were characterized using X-ray diffraction, atomic force microscopy and UV-Vis Spectrophotometer. X-ray diffraction patterns indicated that the films were polycrystalline with prominent peak attributed to (221) plane of orthorhombic crystal structure. The films prepared at 80 min showed significant increased in the intensity of all diffractions. According to AFM images, these films indicated that the surface of substrate was covered completely. The obtained films also produced higher absorption characteristics when compared to the films prepared at other deposition periods based on optical absorption studies. The band gap values of films deposited at different deposition periods were in the range of 1.6-2.1 eV. Deposition for 80 min was found to be the optimum condition to produce good quality thin films under the current conditions. (author).
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DEFF Research Database (Denmark)
Taboryski, Rafael Jozef; Kutchinsky, Jonatan; Kuhn, Oliver
1998-01-01
Particularly high transmittivity superconductor-semiconductor barriers formed by MBE growth have been used to form short Josephson planar type Superconductor-Normal-metal-Superconductor (SNS) Josephson junctions with lengths down to 1 mu m. In these junctions the quasiparticles move diffusively...... across the normal region and carry along the phase information given to them by Andreev reflections at both SN boundaries. In order to probe the importance of the coherent transport of quasiparticles in the normal region, we formed one of the superconducting electrodes of the junction as an open loop i...
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The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance
Energy Technology Data Exchange (ETDEWEB)
Cheraghizade, Mohsen [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Jamali-Sheini, Farid, E-mail: faridjamali@iauahvaz.ac.ir [Advanced Surface Engineering and Nano Materials Research Center, Department of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Yousefi, Ramin [Department of Physics, Masjed-Soleiman Branch, Islamic Azad University (I.A.U), Masjed-Soleiman (Iran, Islamic Republic of); Niknia, Farhad [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Mahmoudian, Mohammad Reza [Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916, Tehran (Iran, Islamic Republic of); Sookhakian, Mehran [Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)
2017-07-01
In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn{sub 2}S{sub 3}, and hexagonal phase of SnS{sub 2}. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.
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Social network usage, shame, guilt and pride among high school students: Model testing
Doğan, Uğur; Çelik, Eyüp; Karakaş, Yahya
2016-01-01
This study was aimed at testing a model which applies structural equation modeling (SEM) to explain social networking sites (SNS) usage. Performing SEM with a sample of 500 high school students (40% male, 60% female), the model examined the relationships among shame, guilt and pride on SNS, such Facebook and Twitter. It was hypothesized that SNS usage was predicted directly by shame and indirectly by pride and guilt. The SEM showed that shame affected SNS usage directly and positively, while ...
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Status of the ISAC-II Accelerator at TRIUMF
Laxdal, Robert E; Bricault, Pierre; Bylinskii, Iouri; Fong, Ken; Marchetto, Marco; Mitra, Amiya K; Poirier, Roger L; Rawnsley, William R; Schmor, Paul; Sekachev, Igor; Stanford, Guy; Stinson, Glen; Zviagintsev, Vladimir
2005-01-01
A heavy ion superconducting linac is being installed at TRIUMF to increase the final energy of radioactive beams at ISAC. A first stage of 20MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being installed with initial beam commissioning scheduled for Dec. 2005. The initial cryomodule has met cryogenic and rf performance specifications. In addition we have demonstrated acceleration of alpha particles in an off-line test. A 500W refrigerator system has been installed and commissioned in Jan. 2005 with cold distribution due for commissioning in Sept. 2005. A transfer beamline from the ISAC accelerator and beam transport to a first experimental station are being installed. The status of the project will be presented.
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McDougall, Matthew A; Walsh, Michael; Wattier, Kristina; Knigge, Ryan; Miller, Lindsey; Stevermer, Michalene; Fogas, Bruce S
2016-12-30
This study examined whether Social Networking Sites (SNSs) have a negative moderator effect on the established relationship between perceived social support and depression in psychiatric inpatients. Survey instruments assessing for depression, perceived social support, and SNS use, were filled out by 301 psychiatric inpatients. Additional data on age, gender, and primary psychiatric diagnosis were collected. A step-wise multiple regression analysis was performed to determine significant interactions. There was no significant interaction of SNS use on the relationship between perceived social support and depression when measured by Social Media Use Integration Scale or by hours of SNS use per day. There was a significant negative relationship between perceived social support and depression, and a significant positive relationship between hours of SNS use per day and depression, measured by the Beck Depression Inventory-II. Limitations include a gender discrepancy among participants, generalizability, recall bias, and SNS measurement. This is the first study to look at SNS use and depression in psychiatric inpatients. SNS use did not affect perceived social support or the protective relationship between perceived social support and depression. Hours of SNS use per day were correlated with depression scores. Future studies between SNS use and depression should quantify daily SNS use. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
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I'm dreaming of a white clean room...
Katarina Anthony
2014-01-01
New HIE-ISOLDE cryomodules are now under construction in a state-of-the-art clean room facility in SM18. The HIE-ISOLDE clean rooms in SM18. HIE-ISOLDE is set to be the world's leading nuclear physics site, ultimately accelerating radioactive nuclei to an impressive 10 MeV/u. Helping the facility reach this energy are new superconducting cryomodules, the first quarter-wave cavity module to be assembled at CERN and necessitating a custom clean-room in SM18. At a towering five metres tall, the new clean room houses a custom assembly frame and associated equipment, moving the components of the 6 tonne cryomodules both vertically and horizontally while they are being assembled. "Each cryomodule is made up of some 10,000 parts, which have come from across the continents to be assembled here," says CERN TE engineer Lloyd Williams, who is managing quality assurance for the project. "Each part is checked by the CERN team, catalogued and thoroughly cleaned, befor...
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Cryogenic Hazard at ESS – strategy, safety studies and lessons learned
CERN. Geneva
2016-01-01
The European Spallation Source (ESS) is building a linear accelerator (linac) aiming at delivering a 2 GeV proton beam on a tungsten target wheel at 5 MW nominal power. The entire accelerator will be housed in an underground tunnel and will be fully operational by 2023. The superconducting section of the linac is composed of 21 High Beta cryomodules, 9 Medium Beta cryomodules and 13 Spoke cryomodules, as well as a Cryogenic Distribution System (CDS) that will be provided with liquid helium. A total of 146 superconducting radio frequency (SRF) cavities operating at 2 K will be housed in those cryomodules. Additionally, cryogenic fluids will also be used for the cold hydrogen moderator surrounding the target as well as for several neutron instruments. In order to achieve a proper cooling, different facilities are being built to house the future cryogenic installation and therefore will be subject to Oxygen Deficiency Hazard (ODH). In order to address cryogenic safety issues ESS wide, a long-term strategy has ...
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Cryomdoule Test Stand Reduced-Magnetic Support Design at Fermilab
Energy Technology Data Exchange (ETDEWEB)
McGee, Mike [Fermilab; Chandrasekaran, Saravan Kumar [Fermilab; Crawford, Anthony [Fermilab; Harms, Elvin [Fermilab; Leibfritz, Jerry [Fermilab; Wu, Genfa [Fermilab
2016-06-01
In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These devices will be tested at Fermilab's Cryomodule Test Facility (CMTF) within the Cryomodule Test Stand (CMTS-1) cave. The problem of magnetic pollution became one of major issues during design stage of the LCLS-II cryomodule as the average quality factor of the accelerating cavities is specified to be 2.7 x 10¹⁰. One of the possible ways to mitigate the effect of stray magnetic fields and to keep it below the goal of 5 mGauss involves the application of low permeable materials. Initial permeability and magnetic measurement studies regarding the use of 316L stainless steel material indicated that cold work (machining) and heat affected zones from welding would be acceptable.
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Lin, Ruoyun; Utz, Sonja
2017-05-01
On social media, users can easily share their feelings, thoughts, and experiences with the public, including people who they have no previous interaction with. Such information, though often embedded in a stream of others' news, may influence recipients' perception toward the discloser. We used a special design that enables a quasi-experience of SNS browsing, and examined if browsing other's posts in a news stream can create a feeling of familiarity and (even) closeness toward the discloser. In addition, disclosure messages can vary in the degree of intimacy (from superficial to intimate) and narrativity (from a random blather to a story-like narrative). The roles of disclosure intimacy and narrativity on perceived closeness and social attraction were examined by a 2 × 2 experimental design. By conducting one lab study and another online replication, we consistently found that disclosure frequency, when perceived as appropriate, predicted familiarity and closeness. The effects of disclosure intimacy and narrativity were not stable. Further exploratory analyses showed that the roles of disclosure intimacy on closeness and social attraction were constrained by the perceived appropriateness, and the effects of narrativity on closeness and social attraction were mediated by perceived entertainment value.
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Mounting power cables on SOLEIL
Laurent Guiraud
1999-01-01
The power couplers are mounted on the SOLEIL cryomodule in a clean room. The cryomodule will allow superconducting technology to be used at SOLEIL, the French national synchrotron facility. This work is carried out as part of a collaboration between CERN and CEA Saclay, the French National Atomic Energy Commission.
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International Nuclear Information System (INIS)
Xue, Xiaopan; Tian, Jianhua; Liao, Wenming; Shan, Zhongqiang
2014-01-01
Highlights: • Spherical anatase TiO 2 covered with nanospindles (SNS) were employed in DSSCs. • SNS possess the dual functions of light scattering and high dye loading. • SNS were fabricated through a facile hydrothermal treatment of the precursors. • Precursors were synthesized by controlled hydrolysis of TBT after being diluted. • The cells based on SNS-18/P25 photoanode exhibited advanced performance. - Abstract: Spherical anatase TiO 2 covered with nanospindles (SNS) were fabricated through a facile hydrothermal treatment of precursors in the presence of ammonia. The precursors were synthesized by controlling hydrolysis rate of TBT (tetrabutyl titanate) in ethanol. Organic structure directing agents and toxic reagents were avoided in the two–step process. By scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), it is confirmed that the morphology and structure of the products can be controlled by adjusting hydrothermal treatment conditions. Time dependent trails revealed the growth mechanism of SNS, which indicating that ammonia can not only retard the dissolution of precursors but also make TiO 2 grow selectively along the direction. Furthermore, photocurrent-potential (I-V) curves show that the solar cells fabricated with the SNS collected after 18 h hydrothermal treatment (SNS-18) exhibit the highest solar energy conversion efficiency. The efficiency is improved by 24.5% compared with that of the cells fabricated with pure P25. Based on the UV-Vis spectrum, nitrogen sorption and IPCE analysis, the improved performance can be attributed to the enhanced scattering and increased active sites for dye loading. Therefore, the dual functions of light scattering and many active sites for dye loading make SNS superior candidates for DSSCs
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Lee, H Erin; Cho, Jaehee
2018-04-13
This study examined the relationships across social media use, social support, depression, and general psychological disposition among people with movement or mobility disabilities in Korea. First, with survey data (n = 91) collected from users of social network sites (SNSs) and online communities, hypotheses regarding positive associations between intensity of an individual's engagement in social media and four different types of social support-emotional, instrumental, informational, and appraisal support-were tested as well as hypotheses regarding mediation effects of the social support variables in the association between social media use and depression. Second, through focus group interviews (n = 15), influences of social media use on social support were more thoroughly explored as well as their influences on general psychological disposition. Results from hierarchical regression analyses confirmed that both intensity of SNS use and online community use significantly predicted instrumental, informational, and appraisal support, while they did not predict emotional support. Further regression and Sobel tests showed that higher levels of intensity of SNS use and of online community use both led to lower levels of depression through the mediation of instrumental and informational support. Analysis of the interviews further revealed the positive roles of social media use in building social support and healthy psychological dispositions. However, analysis also revealed some negative consequences of and limitations to social media use for those with physical disabilities. These findings expand our knowledge of the context and implications of engaging in online social activities for people with physical disabilities.
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Towards smart service networks : An interdisciplinary diagnostic framework
Wang, Yan; Taher, Yehia; van den Heuvel, Willem-Jan
2015-01-01
Service Networks (SNs) are open systems accommodating the co-production of new knowledge and services through organic peer-to-peer interactions. Key to broad success of SNs in practice is their ability to foster and ensure a high performance. By performance we mean the joint effort of tremendous
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Cavity Processing and Preparation of 650 MHz Elliptical Cell Cavities for PIP-II
Energy Technology Data Exchange (ETDEWEB)
Rowe, Allan [Fermilab; Chandrasekaran, Saravan Kumar [Fermilab; Grassellino, Anna [Fermilab; Melnychuk, Oleksandr [Fermilab; Merio, Margherita [Fermilab; Reid, Thomas [Argonne (main); Sergatskov, Dmitri [Fermilab
2017-05-01
The PIP-II project at Fermilab requires fifteen 650 MHz SRF cryomodules as part of the 800 MeV LINAC that will provide a high intensity proton beam to the Fermilab neutrino program. A total of fifty-seven high-performance SRF cavities will populate the cryomodules and will operate in both pulsed and continuous wave modes. These cavities will be processed and prepared for performance testing utilizing adapted cavity processing infrastructure already in place at Fermilab and Argonne. The processing recipes implemented for these structures will incorporate state-of-the art processing and cleaning techniques developed for 1.3 GHz SRF cavities for the ILC, XFEL, and LCLS-II projects. This paper describes the details of the processing recipes and associated chemistry, heat treatment, and cleanroom processes at the Fermilab and Argonne cavity processing facilities. This paper also presents single and multi-cell cavity test results with quality factors above 5·10¹⁰ and accelerating gradients above 30 MV/m.
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Zhang, Baidong; Li, Yan; Zhang, Huixiao; Ai, Chunzhi
2010-11-02
Development of anticancer drugs targeting Aurora B, an important member of the serine/threonine kinases family, has been extensively focused on in recent years. In this work, by applying an integrated computational method, including comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), homology modeling and molecular docking, we investigated the structural determinants of Aurora B inhibitors based on three different series of derivatives of 108 molecules. The resultant optimum 3D-QSAR models exhibited (q(2) = 0.605, r(2) (pred) = 0.826), (q(2) = 0.52, r(2) (pred) = 0.798) and (q(2) = 0.582, r(2) (pred) = 0.971) for MK-0457, GSK1070916 and SNS-314 classes, respectively, and the 3D contour maps generated from these models were analyzed individually. The contour map analysis for the MK-0457 model revealed the relative importance of steric and electrostatic effects for Aurora B inhibition, whereas, the electronegative groups with hydrogen bond donating capacity showed a great impact on the inhibitory activity for the derivatives of GSK1070916. Additionally, the predictive model of the SNS-314 class revealed the great importance of hydrophobic favorable contour, since hydrophobic favorable substituents added to this region bind to a deep and narrow hydrophobic pocket composed of residues that are hydrophobic in nature and thus enhanced the inhibitory activity. Moreover, based on the docking study, a further comparison of the binding modes was accomplished to identify a set of critical residues that play a key role in stabilizing the drug-target interactions. Overall, the high level of consistency between the 3D contour maps and the topographical features of binding sites led to our identification of several key structural requirements for more potency inhibitors. Taken together, the results will serve as a basis for future drug development of inhibitors against Aurora B kinase for various tumors.
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International Nuclear Information System (INIS)
Reece, C.E.; Drury, M.; Rao, M.G.; Nguyen-Tuong, V.
1997-01-01
The useful performance range of the superconducting rf (SRF) cavities in the CEBAF accelerator at Jefferson Lab is frequently limited by electron field emission and derived phenomena. Improvements are required to support future operation of the accelerator at higher than 5 GeV. Twelve operational cryomodules have been successfully processed to higher useful operating gradients via rf-helium processing. Progress against field emission was evidenced by improved high-field Q, reduced x-ray production and greatly reduced incidence of arcing at the cold ceramic window. There was no difficulty reestablishing beamline vacuum following the processing. Cavities previously limited to 4-6 MV/m are now operating stably at 6-9 MV/m. By applying a pulsed-rf processing technique, we have also improved the pressure stability of the thermal transition region of the input waveguide for several cavities
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Hardin, Robert A; Liu, Yun; Long, Cary; Aleksandrov, Alexander; Blokland, Willem
2011-02-14
A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 μrad (horizontal) to 4 μrad (vertical), corresponding to beam drifts of only 0.5 mm × 1 mm at the furthest measurement station located 250 meters away from the light source.
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Status of the HIE-ISOLDE Project at CERN
Kadi, Y; Blumenfeld, Y; Bravin, E; Calatroni, S; Catherall, R; Fraser, M A; Goddard, B; Parchet, D; Siesling, E; Vandoni, G; Venturini Delsolaro, W; Voulot, D; Williams, L R
2012-01-01
The HIE-ISOLDE project represents a major upgrade of the ISOLDE facility with a mandate to significantly improve the quality and increase the intensity and energy of radioactive nuclear beams produced at CERN. The project will expand the experimental nuclear physics programme at ISOLDE by focusing on an upgrade of the existing REX linac with a 40 MV superconducting linac comprising thirty-two niobium-on-copper sputter-coated quarter-wave resonators housed in six cryomodules. The new linac will raise the energy of post-accelerated beams from 3 MeV/u to over 10 MeV/u. The upgrade will be staged to first deliver beam energies of 5.5 MeV/u using two high-β cryomodules placed downstream of REX, before the energy variable section of the existing linac is replaced with two low-β cryomodules and two additional high-β cryomodules are installed to attain over 10 MeV/u with full energy variability from as low as 0.45 MeV/u. An overview of the project including a status summary of the different R&D activities and ...
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Solution processed Cu2SnS3 thin films for visible and infrared photodetector applications
Directory of Open Access Journals (Sweden)
Sandra Dias
2016-02-01
Full Text Available The Cu2SnS3 thin films were deposited using an economic, solution processible, spin coating technique. The films were found to possess a tetragonal crystal structure using X-ray diffraction. The film morphology and the particle size were determined using scanning electron microscopy. The various planes in the crystal were observed using transmission electron microscopy. The optimum band gap of 1.23 eV and a high absorption coefficient of 104 cm−1 corroborate its application as a photoactive material. The visible and infrared (IR photo response was studied for various illumination intensities. The current increased by one order from a dark current of 0.31 μA to a current of 1.78 μA at 1.05 suns and 8.7 μA under 477.7 mW/cm2 IR illumination intensity, at 3 V applied bias. The responsivity, sensitivity, external quantum efficiency and specific detectivity were found to be 10.93 mA/W, 5.74, 2.47% and 3.47 × 1010 Jones respectively at 1.05 suns and 16.32 mA/W, 27.16, 2.53% and 5.10 × 1010 Jones respectively at 477.7 mW/cm2 IR illumination. The transient photoresponse was measured both for visible and IR illuminations.
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Directory of Open Access Journals (Sweden)
Miki Kaneko
2015-10-01
Full Text Available Soft neurological signs (SNS are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm movement in childhood. In this study, we focused on pronation and supination, which are arm movements included in the SNS examination. Two hundred and twenty-three typically developing children aged 4–12 years (107 boys, 116 girls and 18 adults aged 21–26 years (16 males, two females participated in the experiment. To quantify SNS during pronation and supination, we calculated several evaluation index scores: bimanual symmetry, compliance, postural stability, motor speed and mirror movement. These index scores were evaluated using data obtained from sensors attached to the participants’ hands and elbows. Each score increased as age increased. Results obtained using our system showed developmental changes that were consistent with criteria for SNS. We were able to successfully quantify SNS during pronation and supination. These results indicate that it may be possible to use our system as quantitative criteria for evaluating development of neurological function.
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Kaneko, Miki; Yamashita, Yushiro; Inomoto, Osamu; Iramina, Keiji
2015-10-12
Soft neurological signs (SNS) are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm movement in childhood. In this study, we focused on pronation and supination, which are arm movements included in the SNS examination. Two hundred and twenty-three typically developing children aged 4-12 years (107 boys, 116 girls) and 18 adults aged 21-26 years (16 males, two females) participated in the experiment. To quantify SNS during pronation and supination, we calculated several evaluation index scores: bimanual symmetry, compliance, postural stability, motor speed and mirror movement. These index scores were evaluated using data obtained from sensors attached to the participants' hands and elbows. Each score increased as age increased. Results obtained using our system showed developmental changes that were consistent with criteria for SNS. We were able to successfully quantify SNS during pronation and supination. These results indicate that it may be possible to use our system as quantitative criteria for evaluating development of neurological function.
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How do general practice residents use social networking sites in asynchronous distance learning?
Maisonneuve, Hubert; Chambe, Juliette; Lorenzo, Mathieu; Pelaccia, Thierry
2015-09-21
Blended learning environments - involving both face-to-face and remote interactions - make it easier to adapt learning programs to constraints such as residents' location and low teacher-student ratio. Social networking sites (SNS) such as Facebook®, while not originally intended to be used as learning environments, may be adapted for the distance-learning part of training programs. The purpose of our study was to explore the use of SNS for asynchronous distance learning in a blended learning environment as well as its influence on learners' face-to-face interactions. We conducted a qualitative study and carried out semi-structured interviews. We performed purposeful sampling for maximal variation to include eight general practice residents in 2(nd) and 3(rd) year training. A thematic analysis was performed. The social integration of SNS facilitates the engagement of users in their learning tasks. This may also stimulate students' interactions and group cohesion when members meet up in person. Most of the general practice residents who work in the blended learning environment we studied had a positive appraisal on their use of SNS. In particular, we report a positive impact on their engagement in learning and their participation in discussions during face-to-face instruction. Further studies are needed in order to evaluate the effectiveness of SNS in blended learning environments and the appropriation of SNS by teachers.
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Investigation of user behavior on social networking sites.
Waheed, Hajra; Anjum, Maria; Rehman, Mariam; Khawaja, Amina
2017-01-01
Social networking sites (SNS) are used for social and professional interaction with people. SNS popularity has encouraged researchers to analyze the relationship of activities performed on SNS with user behavior. In doing so, the term "user behavior" is rather used ambiguously with different interpretations, which makes it difficult to identify studies on user behavior in relation to SNS. This phenomenon has encouraged this thorough research on the characteristics of user behavior being discussed in the literature. Therefore, in this study, we aim to identify, analyze, and classify the characteristics associated with user behavior to answer the research questions designed to conduct this research. A mapping study (also called scoping study), which is a type of systematic literature review, is employed to identify potential studies from digital databases through a developed protocol. Thematic analysis is carried out for the classification of user behavior. We identified 116 primary studies for full analysis. This study found seven characteristics associated with behavior that have direct influence on SNS use and nine factors that have an indirect effect. All studies were conducted largely under seven areas that set the context of these studies. Findings show that the research on SNS is still in its early stage. The range of topics covered in the analyzed studies is quite expansive, although the depth in terms of number of studies under each topic is quite limited. This study reports that activities performed on SNS are either associated with user behavior or reflect personality characteristics. The findings of this study could be used by practitioners to evaluate their SNS platforms and develop more user-centered applications. These studies can also help organizations to understand better the needs of their employees.
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Investigation of user behavior on social networking sites.
Directory of Open Access Journals (Sweden)
Hajra Waheed
Full Text Available Social networking sites (SNS are used for social and professional interaction with people. SNS popularity has encouraged researchers to analyze the relationship of activities performed on SNS with user behavior. In doing so, the term "user behavior" is rather used ambiguously with different interpretations, which makes it difficult to identify studies on user behavior in relation to SNS. This phenomenon has encouraged this thorough research on the characteristics of user behavior being discussed in the literature. Therefore, in this study, we aim to identify, analyze, and classify the characteristics associated with user behavior to answer the research questions designed to conduct this research. A mapping study (also called scoping study, which is a type of systematic literature review, is employed to identify potential studies from digital databases through a developed protocol. Thematic analysis is carried out for the classification of user behavior. We identified 116 primary studies for full analysis. This study found seven characteristics associated with behavior that have direct influence on SNS use and nine factors that have an indirect effect. All studies were conducted largely under seven areas that set the context of these studies. Findings show that the research on SNS is still in its early stage. The range of topics covered in the analyzed studies is quite expansive, although the depth in terms of number of studies under each topic is quite limited. This study reports that activities performed on SNS are either associated with user behavior or reflect personality characteristics. The findings of this study could be used by practitioners to evaluate their SNS platforms and develop more user-centered applications. These studies can also help organizations to understand better the needs of their employees.
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International Nuclear Information System (INIS)
Lin, Zuohong; Feng, Kai; Tu, Heng; Kang, Lei; Lin, Zheshuai; Yao, Jiyong; Wu, Yicheng
2014-01-01
Highlights: • Three new chalcohalides: Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have been synthesized. • The MQ 5 Br octahedra and GeQ 4 tetrahedra form a three-dimensional framework with Ba 2+ in the channels. • Band Gaps and electronic structures of the three compounds were studied. - Abstract: Single crystals of three new chalcohalides: Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have been synthesized for the first time. These isostructural compounds crystallize in the orthorhombic space group Pnma. In the structure, the tetra-valent Ge atom is tetrahedrally coordinated with four Q (Q = S, Se) atoms, while the bi-valent M atom (M = Pb, Sn) is coordinated with an obviously distorted octahedron of five Q (Q = S, Se) atoms and one Br atom, showing the stereochemical activity of the ns 2 lone pair electron. The MQ 5 Br (M = Sn, Pb; Q = S, Se) distorted octahedra and the GeQ 4 (Q = S, Se) tetrahedra are connected to each other to form a three-dimensional framework with channels occupied by Ba 2+ cations. Based on UV–vis–NIR spectroscopy measurements and the electronic structure calculations, Ba 4 Ge 2 PbS 8 Br 2 , Ba 4 Ge 2 PbSe 8 Br 2 and Ba 4 Ge 2 SnS 8 Br 2 have indirect band gaps of 2.054, 1.952, and 2.066 eV respectively, which are mainly determined by the orbitals from the Ge, M and Q atoms (M = Pb, Sn; Q = S, Se)
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Neutronic performance issues for the Spallation Neutron Source moderators
International Nuclear Information System (INIS)
Iverson, E.B.; Murphy, B.D.
2001-01-01
We continue to develop the neutronic models of the Spallation Neutron Source target station and moderators in order to better predict the neutronic performance of the system as a whole and in order to better optimize that performance. While we are not able to say that every model change leads to more intense neutron beams being predicted, we do feel that such changes are advantageous in either performance or in the accuracy of the prediction of performance. We have computationally and experimentally studied the neutronics of hydrogen-water composite moderators such as are proposed for the SNS Project. In performing these studies, we find that the composite moderator, at least in the configuration we have examined, does not provide performance characteristics desirable for the instruments proposed and being designed for this neutron scattering facility. The pulse width as a function of energy is significantly broader than for other moderators, limiting attainable resolution-bandwidth combinations. Furthermore, there is reason to expect that higher-energy (0.1-1 eV) applications will be significantly impacted by bimodal pulse shapes requiring enormous effort to parameterize. As a result of these studies, we have changed the SNS design, and will not use a composite moderator at this time. We have analyzed the depletion of a gadolinium poison plate in a hydrogen moderator at the Spallation Neutron Source, and found that conventional poison thicknesses will be completely unable to last the desired component lifetime of three operational years. A poison plate 300-600 μm thick will survive for the required length of time, but will somewhat degrade the intensity (by as much as 15% depending on neutron energy) and the consistency of the neutron source performance. Our results should scale fairly easily to other moderators on this or any other spallation source. While depletion will be important for all highly-absorbing materials in high-flux regions, we feel it likely that
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Pill-Box Cavity BPM For TESLA Cryomodul
Sargsyan, V
2003-01-01
A new cavity BPM with 10 μm resolution is designed and fabricated to perform single bunch measurements at the TESLA linear collider. In order to have a low energy dissipation in the cryogenic supermodule, the inner surface of the cavity is copper plated. Cross-talk is minimised by a special polarisation design. The electronics, at 1.5 GHz, is a homodyne receiver normalised to the bunch charge. Its LO-signal for down-conversion is taken from the same cavity.
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Directory of Open Access Journals (Sweden)
Chunzhi Ai
2010-11-01
Full Text Available Development of anticancer drugs targeting Aurora B, an important member of the serine/threonine kinases family, has been extensively focused on in recent years. In this work, by applying an integrated computational method, including comparative molecular field analysis (CoMFA, comparative molecular similarity indices analysis (CoMSIA, homology modeling and molecular docking, we investigated the structural determinants of Aurora B inhibitors based on three different series of derivatives of 108 molecules. The resultant optimum 3D-QSAR models exhibited (q2 = 0.605, r2pred = 0.826, (q2 = 0.52, r2pred = 0.798 and (q2 = 0.582, r2pred = 0.971 for MK-0457, GSK1070916 and SNS-314 classes, respectively, and the 3D contour maps generated from these models were analyzed individually. The contour map analysis for the MK-0457 model revealed the relative importance of steric and electrostatic effects for Aurora B inhibition, whereas, the electronegative groups with hydrogen bond donating capacity showed a great impact on the inhibitory activity for the derivatives of GSK1070916. Additionally, the predictive model of the SNS-314 class revealed the great importance of hydrophobic favorable contour, since hydrophobic favorable substituents added to this region bind to a deep and narrow hydrophobic pocket composed of residues that are hydrophobic in nature and thus enhanced the inhibitory activity. Moreover, based on the docking study, a further comparison of the binding modes was accomplished to identify a set of critical residues that play a key role in stabilizing the drug-target interactions. Overall, the high level of consistency between the 3D contour maps and the topographical features of binding sites led to our identification of several key structural requirements for more potency inhibitors. Taken together, the results will serve as a basis for future drug development of inhibitors against Aurora B kinase for various tumors.
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PIP-II Cryogenic System and the evolution of Superfluid Helium Cryogenic Plant Specifications
Energy Technology Data Exchange (ETDEWEB)
Chakravarty, Anindya [Fermilab; Rane, Tejas [Fermilab; Klebaner, Arkadiy [Fermilab
2017-07-06
The PIP-II cryogenic system consists of a Superfluid Helium Cryogenic Plant (SHCP) and a Cryogenic Distribution System (CDS) connecting the SHCP to the Superconducting (SC) Linac consisting of 25 cryomodules. The dynamic heat load of the SC cavities for continuous wave (CW) as well as pulsed mode of operation has been listed out. The static heat loads of the cavities along with the CDS have also been discussed. Simulation study has been carried out to compute the supercritical helium (SHe) flow requirements for each cryomodule. Comparison between the flow requirements of the cryomodules for the CW and pulsed modes of operation have also been made. From the total computed heat load and pressure drop values in the CDS, the basic specifications for the SHCP, required for cooling the SC Linac, have evolved.
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RESULTS OF ACCELERATED LIFE TESTING OF LCLS-II CAVITY TUNER MOTOR
Energy Technology Data Exchange (ETDEWEB)
Huque, Naeem [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Daly, Edward F. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Pischalnikov, Yuriy [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2018-04-01
An Accelerated Life Test (ALT) of the Phytron stepper motor used in the LCLS-II cavity tuner has been conducted at JLab. Since the motor will reside inside the cryomodule, any failure would lead to a very costly and arduous repair. As such, the motor was tested for the equivalent of 30 lifetimes before being approved for use in the production cryomodules. The 9-cell LCLS-II cavity is simulated by disc springs with an equivalent spring constant. Plots of the motor position vs. tuner position ' measured via an installed linear variable differential transformer (LVDT) ' are used to measure motor motion. The titanium spindle was inspected for loss of lubrication. The motor passed the ALT, and is set to be installed in the LCLS-II cryomodules.
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Self-Assembled Cu-Sn-S Nanotubes with High (De)Lithiation Performance.
Lin, Jie; Lim, Jin-Myoung; Youn, Duck Hyun; Kawashima, Kenta; Kim, Jun-Hyuk; Liu, Yang; Guo, Hang; Henkelman, Graeme; Heller, Adam; Mullins, Charles Buddie
2017-10-24
Through a gelation-solvothermal method without heteroadditives, Cu-Sn-S composites self-assemble to form nanotubes, sub-nanotubes, and nanoparticles. The nanotubes with a Cu 3-4 SnS 4 core and Cu 2 SnS 3 shell can tolerate long cycles of expansion/contraction upon lithiation/delithiation, retaining a charge capacity of 774 mAh g -1 after 200 cycles with a high initial Coulombic efficiency of 82.5%. The importance of the Cu component for mitigation of the volume expansion and structural evolution upon lithiation is informed by density functional theory calculations. The self-generated template and calculated results can inspire the design of analogous Cu-M-S (M = metal) nanotubes for lithium batteries or other energy storage systems.
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DEFF Research Database (Denmark)
Kjellsson, Gøsta; Damgaard, Christian; Strandberg, Morten Tune
2005-01-01
"DMU har via EFSAs GMOnet indhentet de nye oplysninger (mail fra SNS d. 14-03-2005) til ansøgningen om godkendelse til markedsføring til import og videreforarbejdning af den genmodificerede majs (1507). DMU har først gennemgået materialet for at undersøge om det ændrer den risikovurdering vi tidl...
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Takahashi, Yoshimitsu; Uchida, Chiyoko; Miyaki, Koichi; Sakai, Michi; Shimbo, Takuro; Nakayama, Takeo
2009-07-23
Internet peer support groups for depression are becoming popular and could be affected by an increasing number of social network services (SNSs). However, little is known about participant characteristics, social relationships in SNSs, and the reasons for usage. In addition, the effects of SNS participation on people with depression are rather unknown. The aim was to explore the potential benefits and harms of an SNS for depression based on a concurrent triangulation design of mixed methods strategy, including qualitative content analysis and social network analysis. A cross-sectional Internet survey of participants, which involved the collection of SNS log files and a questionnaire, was conducted in an SNS for people with self-reported depressive tendencies in Japan in 2007. Quantitative data, which included user demographics, depressive state, and assessment of the SNS (positive vs not positive), were statistically analyzed. Descriptive contents of responses to open-ended questions concerning advantages and disadvantages of SNS participation were analyzed using the inductive approach of qualitative content analysis. Contents were organized into codes, concepts, categories, and a storyline based on the grounded theory approach. Social relationships, derived from data of "friends," were analyzed using social network analysis, in which network measures and the extent of interpersonal association were calculated based on the social network theory. Each analysis and integration of results were performed through a concurrent triangulation design of mixed methods strategy. There were 105 participants. Median age was 36 years, and 51% (36/71) were male. There were 37 valid respondents; their number of friends and frequency of accessing the SNS were significantly higher than for invalid/nonrespondents (P = .008 and P = .003). Among respondents, 90% (28/31) were mildly, moderately, or severely depressed. Assessment of the SNS was performed by determining the access
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Takahashi, Yoshimitsu; Uchida, Chiyoko; Miyaki, Koichi; Sakai, Michi; Shimbo, Takuro
2009-01-01
Background Internet peer support groups for depression are becoming popular and could be affected by an increasing number of social network services (SNSs). However, little is known about participant characteristics, social relationships in SNSs, and the reasons for usage. In addition, the effects of SNS participation on people with depression are rather unknown. Objective The aim was to explore the potential benefits and harms of an SNS for depression based on a concurrent triangulation design of mixed methods strategy, including qualitative content analysis and social network analysis. Methods A cross-sectional Internet survey of participants, which involved the collection of SNS log files and a questionnaire, was conducted in an SNS for people with self-reported depressive tendencies in Japan in 2007. Quantitative data, which included user demographics, depressive state, and assessment of the SNS (positive vs not positive), were statistically analyzed. Descriptive contents of responses to open-ended questions concerning advantages and disadvantages of SNS participation were analyzed using the inductive approach of qualitative content analysis. Contents were organized into codes, concepts, categories, and a storyline based on the grounded theory approach. Social relationships, derived from data of “friends,” were analyzed using social network analysis, in which network measures and the extent of interpersonal association were calculated based on the social network theory. Each analysis and integration of results were performed through a concurrent triangulation design of mixed methods strategy. Results There were 105 participants. Median age was 36 years, and 51% (36/71) were male. There were 37 valid respondents; their number of friends and frequency of accessing the SNS were significantly higher than for invalid/nonrespondents (P = .008 and P = .003). Among respondents, 90% (28/31) were mildly, moderately, or severely depressed. Assessment of the SNS was
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Energy Technology Data Exchange (ETDEWEB)
KleinJan, Gijs H. [Leiden University Medical Hospital, Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden (Netherlands); The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Nuclear Medicine, Amsterdam (Netherlands); Berg, Nynke S. van den [Leiden University Medical Hospital, Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden (Netherlands); The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Urology, Amsterdam (Netherlands); Jong, Jeroen de [The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Pathology, Amsterdam (Netherlands); Wit, Esther M.; Poel, Henk G. van der [The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Urology, Amsterdam (Netherlands); Thygessen, Helene [The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Biostatistics, Amsterdam (Netherlands); Vegt, Erik [The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Nuclear Medicine, Amsterdam (Netherlands); Leeuwen, Fijs W.B. van [Leiden University Medical Hospital, Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden (Netherlands); The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Urology, Amsterdam (Netherlands); The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Department of Head and Neck Surgery and Oncology, Amsterdam (Netherlands)
2016-07-15
Radical prostatectomy and complementary extended pelvic lymph node dissection (ePLND) of sentinel lymph nodes (SNs) and non-sentinel lymph nodes (LNs) at risk of containing metastases are increasingly being performed using high-tech robot-assisted approaches. Although this technological evolution has clear advantages, the physical nature of robotic systems limits the integrated use of routine radioguided surgery technologies. Hence, engineering effort in robotics are focused on the integration of fluorescence guidance technologies. Using the hybrid SN tracer indocyanine green-{sup 99m}Tc-nanocolloid (radioactive and fluorescent), for the first time in combination with a robot-integrated laparoscope, we investigated whether the robot-assisted approach affects the accuracy of fluorescence detection of SNs identified preoperatively using nuclear medicine. The study included 55 patients (Briganti nomogram-based risk >5 % on LN metastases) scheduled for robot-assisted radical prostatectomy, SN biopsy and ePLND. Following indocyanine green-{sup 99m}Tc-nanocolloid injection, preoperative nuclear imaging (lymphoscintigraphy and SPECT/CT) was used to locate the SN(s). The fluorescence laparoscope was used intraoperatively to identify the SN(s) with standard fluorescence settings (in 50 patients) and with customized settings (in 5 patients). The number and location of the SNs, the radioactive, fluorescence (both in vivo and ex vivo) and tumour status of the resected SNs/LNs, and postoperative complications were recorded and analysed. Combined, preoperative lymphoscintigraphy and SPECT/CT imaging identified 212 SNs (median 4 per patient). Intraoperative fluorescence imaging using standard fluorescence settings visualized 80.4 % (148/184 SNs; 50 patients; ex vivo 97.8 %). This increased to 85.7 % (12/14 SNs; 5 patients; ex vivo 100 %) with customized fluorescence settings. SPECT/CT images provided guidance towards the residual SNs. Ex vivo all removed SNs were radioactive. SNs
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International Nuclear Information System (INIS)
KleinJan, Gijs H.; Berg, Nynke S. van den; Jong, Jeroen de; Wit, Esther M.; Poel, Henk G. van der; Thygessen, Helene; Vegt, Erik; Leeuwen, Fijs W.B. van
2016-01-01
Radical prostatectomy and complementary extended pelvic lymph node dissection (ePLND) of sentinel lymph nodes (SNs) and non-sentinel lymph nodes (LNs) at risk of containing metastases are increasingly being performed using high-tech robot-assisted approaches. Although this technological evolution has clear advantages, the physical nature of robotic systems limits the integrated use of routine radioguided surgery technologies. Hence, engineering effort in robotics are focused on the integration of fluorescence guidance technologies. Using the hybrid SN tracer indocyanine green- 99m Tc-nanocolloid (radioactive and fluorescent), for the first time in combination with a robot-integrated laparoscope, we investigated whether the robot-assisted approach affects the accuracy of fluorescence detection of SNs identified preoperatively using nuclear medicine. The study included 55 patients (Briganti nomogram-based risk >5 % on LN metastases) scheduled for robot-assisted radical prostatectomy, SN biopsy and ePLND. Following indocyanine green- 99m Tc-nanocolloid injection, preoperative nuclear imaging (lymphoscintigraphy and SPECT/CT) was used to locate the SN(s). The fluorescence laparoscope was used intraoperatively to identify the SN(s) with standard fluorescence settings (in 50 patients) and with customized settings (in 5 patients). The number and location of the SNs, the radioactive, fluorescence (both in vivo and ex vivo) and tumour status of the resected SNs/LNs, and postoperative complications were recorded and analysed. Combined, preoperative lymphoscintigraphy and SPECT/CT imaging identified 212 SNs (median 4 per patient). Intraoperative fluorescence imaging using standard fluorescence settings visualized 80.4 % (148/184 SNs; 50 patients; ex vivo 97.8 %). This increased to 85.7 % (12/14 SNs; 5 patients; ex vivo 100 %) with customized fluorescence settings. SPECT/CT images provided guidance towards the residual SNs. Ex vivo all removed SNs were radioactive. SNs were
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Summary of CARE-HHH Mini-Workshop on LHC Crab Cavity Validation, 21 August 2008
Calaga, R; Garoby, R; Linnecar, T; Tomás, R; Zimmermann, F; CERN. Geneva. BE Department
2008-01-01
A global LHC crab-cavity collaboration is rapidly advancing the R&D of a complete crab cavity cryomodule and performing the associated beam dynamics simulations compatible with a prototype test in the phase 0/I upgrade with the aim of establishing a full crab crossing scheme for the phase II upgrade of the LHC. A one day CARE-HHH mini-workshop was held on August 21, 2008 at CERN to discuss crab crossing in the LHC phase 0/I & II upgrades and this reports summarizes the activities of the four sessions that took place during the workshop. The goals of this crab-cavity workshop were fourfold: (1) to discuss prospects of crab cavities in LHC upgrades (2) to review the status of the cryomodule development and beam dynamics, (3) to establish validity requirements for LHC crab cavities which need to be demonstrated prior to their installation into the LHC, and (4) to provide guidance & coordination for the global collaborators.
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DEFF Research Database (Denmark)
Bilde, Anders; Von Buchwald, Christian; Mortensen, Jann
2006-01-01
SPECT with higher resolution CT scanners are expected to provide more accurate information about the localization of SNs. OBJECTIVE: To assess the role of combined SPECT-CT in SN identification in the clinically negative neck of patients with OSCC. MATERIALS AND METHODS: Lymphoscintigraphy comprising......CONCLUSION: SPECT-CT may improve the localization of sentinel nodes (SNs) in patients with oral squamous cell carcinoma (OSCC). Compared with planar lymphoscintigraphy SPECT-CT detected more SNs and provided additional anatomical and spatial information about their localization. New generation...... planar and SPECT-CT acquisition was performed in 34 consecutive patients with OSCC stage I and II (T1-2N0M0) prior to sentinel node biopsy (SNB) and selective neck dissection. The number of SNs and anatomical location was recorded according to lymphoscintigraphy and operative findings. RESULTS: SNB...
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Wire Position Monitoring with FPGA based Electronics
International Nuclear Information System (INIS)
Eddy, N.; Lysenko, O.
2009-01-01
This fall the first Tesla-style cryomodule cooldown test is being performed at Fermilab. Instrumentation department is preparing the electronics to handle the data from a set of wire position monitors (WPMs). For simulation purposes a prototype pipe with a WMP has been developed and built. The system is based on the measurement of signals induced in pickups by 320 MHz signal carried by a wire through the WPM. The wire is stretched along the pipe with a tensioning load of 9.07 kg. The WPM consists of four 50 (Omega) striplines spaced 90 o apart. FPGA based digitizer scans the WPM and transmits the data to a PC via VME interface. The data acquisition is based on the PC running LabView. In order to increase the accuracy and convenience of the measurements some modifications were required. The first is implementation of an average and decimation filter algorithm in the integrator operation in the FPGA. The second is the development of alternative tool for WPM measurements in the PC. The paper describes how these modifications were performed and test results of a new design. The last cryomodule generation has a single chain of seven WPMs (placed in critical positions: at each end, at the three posts and between the posts) to monitor a cold mass displacement during cooldown. The system was developed in Italy in collaboration with DESY. Similar developments have taken place at Fermilab in the frame of cryomodules construction for SCRF research. This fall preliminary cryomodule cooldown test is being performed. In order to prepare an appropriate electronic system for the test a prototype pipe with a WMP has been developed and built, figure 1. The system is based on the measurement of signals induced in pickups by 320 MHz signal carried by a wire through the WPM. The 0.5 mm diameter Cu wire is stretched along the pipe with a tensioning load of 9.07 kg and has a length of 1.1 m. The WPM consists of four 50 (Omega) striplines spaced 90 o apart. An FPGA based digitizer
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KleinJan, Gijs H; van den Berg, Nynke S; de Jong, Jeroen; Wit, Esther M; Thygessen, Helene; Vegt, Erik; van der Poel, Henk G; van Leeuwen, Fijs W B
2016-07-01
Radical prostatectomy and complementary extended pelvic lymph node dissection (ePLND) of sentinel lymph nodes (SNs) and non-sentinel lymph nodes (LNs) at risk of containing metastases are increasingly being performed using high-tech robot-assisted approaches. Although this technological evolution has clear advantages, the physical nature of robotic systems limits the integrated use of routine radioguided surgery technologies. Hence, engineering effort in robotics are focused on the integration of fluorescence guidance technologies. Using the hybrid SN tracer indocyanine green-(99m)Tc-nanocolloid (radioactive and fluorescent), for the first time in combination with a robot-integrated laparoscope, we investigated whether the robot-assisted approach affects the accuracy of fluorescence detection of SNs identified preoperatively using nuclear medicine. The study included 55 patients (Briganti nomogram-based risk >5 % on LN metastases) scheduled for robot-assisted radical prostatectomy, SN biopsy and ePLND. Following indocyanine green-(99m)Tc-nanocolloid injection, preoperative nuclear imaging (lymphoscintigraphy and SPECT/CT) was used to locate the SN(s). The fluorescence laparoscope was used intraoperatively to identify the SN(s) with standard fluorescence settings (in 50 patients) and with customized settings (in 5 patients). The number and location of the SNs, the radioactive, fluorescence (both in vivo and ex vivo) and tumour status of the resected SNs/LNs, and postoperative complications were recorded and analysed. Combined, preoperative lymphoscintigraphy and SPECT/CT imaging identified 212 SNs (median 4 per patient). Intraoperative fluorescence imaging using standard fluorescence settings visualized 80.4 % (148/184 SNs; 50 patients; ex vivo 97.8 %). This increased to 85.7 % (12/14 SNs; 5 patients; ex vivo 100 %) with customized fluorescence settings. SPECT/CT images provided guidance towards the residual SNs. Ex vivo all removed SNs were radioactive. SNs
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International Nuclear Information System (INIS)
Lin, Xianzhong; Kavalakkatt, Jaison; Kornhuber, Kai; Levcenko, Sergiu; Lux-Steiner, Martha Ch.; Ennaoui, Ahmed
2013-01-01
Cu 2 ZnSnS 4 (CZTS) has been considered as an alternative absorber layer to Cu(In,Ga)Se 2 due to its earth abundant and environmentally friendly constituents, optimal direct band gap of 1.4–1.6 eV and high absorption coefficient in the visible range. In this work, we propose a solution-based chemical route for the preparation of CZTS thin film absorbers by spin coating of the precursor inks composed of Cu 3 SnS 4 and ZnS NPs and annealing in Ar/H 2 S atmosphere. X-ray diffraction and Raman spectroscopy were used to characterize the structural properties. The chemical composition was determined by energy dispersive X-ray spectroscopy. Optical properties of the CZTS thin film absorbers were studied by transmission, reflection and photoluminescence spectroscopy
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Chaudhari, J. J.; Joshi, U. S.
2018-03-01
Cu2SnS3 (CTS) is an emerging ternery chalcogenide material with great potential application in thin film solar cells. We present here high quality Cu2SnS3 thin films using a facile spin coating method. The as deposited films of CTS were sulphurized in a graphite box using tubular furnace at 520 °C for 60 min at the rate of 2.83 °C min-1 in argon atmosphere. X-ray diffraction (XRD) and Raman spectroscopy studies confirm tetragonal phase and absence of any secondary phase in sulphurized CTS thin films. X-ray photoelectron spectroscopy (XPS) demonstrates that Cu and Sn are in +1 and +4 oxidation state respectively. Surface morphology of CTS films were analyzed by field emission scanning electron microscope and atomic force microscope (AFM), which revealed a smooth surface with roughness (RMS) of 6.32 nm for sulphurized CTS film. Hall measurements confirmed p-type conductivity with hole concentartion of sulphurized CTS thin film is of 6.5348 × 1020 cm-3. UV-vis spectra revealed a direct energy band gap varies from 1.45 eV to 1.01 eV for as-deposited and sulphurized CTS thin film respectively. Such band gap values are optimum for semiconductor material as an absorber layer of thin film solar cell. The CTS thin film solar cell had following structure: SLG/FTO/ZnO/CTS/Al with short circuit current density of (Jsc) of 11.6 mA cm-2, open circuit voltage (Voc) of 0.276 V, active area of 0.16 cm2, fill factor (FF) of 35% and power conversion efficiency of 1.12% under AM 1.5 (100 mW cm-2) illumination in simulated standard test conditions.
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Doleans, Marc
2016-12-01
An in-situ plasma processing technique has been developed at the Spallation Neutron Source (SNS) to improve the performance of the superconducting radio-frequency (SRF) cavities in operation. The technique uses a low-density reactive neon-oxygen plasma at room-temperature to improve the surface work function, to help remove adsorbed gases on the RF surface, and to reduce its secondary emission yield. SNS SRF cavities have six accelerating cells and the plasma typically ignites in the cell where the electric field is the highest. This article details the technique to ignite and monitor the plasma in each cell of the SNS cavities.
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International Nuclear Information System (INIS)
Ciovati, G.; Geng, R.; Lushtak, Y.; Manini, P.; Maccallini, E.; Stutzman, M.
2017-01-01
The use of non-evaporable getter (NEG) pumps in particle accelerators has increased significantly over the past few years because of their large pumping speed, particularly for hydrogen, compared to the size of the pump. A concern about using such pumps in superconducting radio-frequency (SRF) accelerators is the possibility of shedding particulates which could then migrate into the SRF cavities and produce field emission, therefore degrading the cavity performance. One option to mitigate such issue is to use sintered getter materials which intrinsically offer superior mechanical and particle retention properties. In this article we present the results from cryogenic RF tests of a high-gradient SRF cavity after being evacuated several times with an NEG pump equipped with sintered getter disks and placed in close proximity to the cavity. The results showed that the cavity performance was not affected by the pump up to the quench gradient of 34 MV/m. As a result of this study, two such NEG pumps have been installed next to a cryomodule in the CEBAF accelerator to maintain ultra-high vacuum in the SRF cryomodule and two adjacent warm girder sections.
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Energy Technology Data Exchange (ETDEWEB)
Ciovati, G., E-mail: gciovati@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Geng, R. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Lushtak, Y.; Manini, P.; Maccallini, E. [SAES Getters, S.p.A, Viale Italia, 77, 20020 Lainate, MI (Italy); Stutzman, M. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)
2017-01-11
The use of non-evaporable getter (NEG) pumps in particle accelerators has increased significantly over the past few years because of their large pumping speed, particularly for hydrogen, compared to the size of the pump. A concern about using such pumps in superconducting radio-frequency (SRF) accelerators is the possibility of shedding particulates which could then migrate into the SRF cavities and produce field emission, therefore degrading the cavity performance. One option to mitigate such issue is to use sintered getter materials which intrinsically offer superior mechanical and particle retention properties. In this article we present the results from cryogenic RF tests of a high-gradient SRF cavity after being evacuated several times with an NEG pump equipped with sintered getter disks and placed in close proximity to the cavity. The results showed that the cavity performance was not affected by the pump up to the quench gradient of 34 MV/m. As a result of this study, two such NEG pumps have been installed next to a cryomodule in the CEBAF accelerator to maintain ultra-high vacuum in the SRF cryomodule and two adjacent warm girder sections.
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International Nuclear Information System (INIS)
Nielsen, Kristina Rue; Nielsen, Michael B.; Chakera, Annette H.; Hesse, Birger; Oturai, Peter S.; Scolyer, Richard A.; Stretch, Jonathan F.; Thompson, John F.; Uren, Roger F.
2011-01-01
The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients. Three hundred and seven consecutive melanoma patients referred for SN biopsy (SNB) were examined using combined imaging. Secondary interpretation of only the delayed static images was subsequently performed. In 220 patients (72%), complete surgical and pathological information relating to the SNB was available. The number of SNs identified and number of patients with positive SNs were compared between the two interpretations of the imaging studies and, when available, related to pathology data. A slightly higher number of SNs (mean 0.12/patient) was identified when interpreting only delayed static images compared to combined imaging. In a direct patient-to-patient comparison, the number of SN(s) identified on the combined vs static images only showed moderate agreement (kappa value 0.56). In 38 patients (17%), positive SNs were identified by the combined procedure compared to 35 (16%) by static imaging only. Thus by static imaging only, tumour-positive SNs were not identified in 3 of 38 patients (8%). For SN identification in melanoma patients, dynamic imaging combined with delayed static imaging and SPECT/CT is superior to delayed static imaging only because the latter is more likely to fail to identify SNs containing metastases. (orig.)
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Microphonics Testing of the CEBAF Upgrade 7-Cell Cavity
International Nuclear Information System (INIS)
G.K. Davis; J.R. Delayen; M. Drury; T. Hiatt; C. Hovater; T. Powers; J. Preble
2001-01-01
An upgrade cryomodule is being developed for CEBAF at Jefferson Lab. In support of this effort, vibration testing was performed on a single SRF cavity at cryogenic temperature in a Horizontal Test Bed. The tests included response to excitation from background vibration, swept sinusoids, high-power RF pulses, and mechanical impulses. Test procedures, apparatus, and results are presented, along with a description of planned follow-up tests
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Jackson, Brian A; Faith, Kay Sullivan
2013-02-01
Although significant progress has been made in measuring public health emergency preparedness, system-level performance measures are lacking. This report examines a potential approach to such measures for Strategic National Stockpile (SNS) operations. We adapted an engineering analytic technique used to assess the reliability of technological systems-failure mode and effects analysis-to assess preparedness. That technique, which includes systematic mapping of the response system and identification of possible breakdowns that affect performance, provides a path to use data from existing SNS assessment tools to estimate likely future performance of the system overall. Systems models of SNS operations were constructed and failure mode analyses were performed for each component. Linking data from existing assessments, including the technical assistance review and functional drills, to reliability assessment was demonstrated using publicly available information. The use of failure mode and effects estimates to assess overall response system reliability was demonstrated with a simple simulation example. Reliability analysis appears an attractive way to integrate information from the substantial investment in detailed assessments for stockpile delivery and dispensing to provide a view of likely future response performance.
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The Spallation Neutron Source RF Reference System
Piller, Maurice; Crofford, Mark; Doolittle, Lawrence; Ma, Hengjie
2005-01-01
The Spallation Neutron Source (SNS) RF Reference System includes the master oscillator (MO), local oscillator(LO) distribution, and Reference RF distribution systems. Coherent low noise Reference RF signals provide the ability to control the phase relationships between the fields in the front-end and linear accelerator (linac) RF cavity structures. The SNS RF Reference System requirements, implementation details, and performance are discussed.
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Rehm, C
2002-01-01
Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror neutron guides with very high critical angles for total reflection. In this contribution, we will discuss how the performance of a modern neutron-scattering instrument depends on the efficiency of these supermirrors. We summarize current limitations of supermirror coatings and outline ideas for enhancing their performance, particularly for improving the reflec...
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International Nuclear Information System (INIS)
Akutsu, Yasushi; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Kawamura, Mitsuharu; Asano, Taku; Hamazaki, Yuji; Tanno, Kaoru; Kobayashi, Youichi; Suyama, Jumpei; Shinozuka, Akira; Gokan, Takehiko
2010-01-01
Neuronal system activity plays an important role for the prognosis of patients with atrial fibrillation (AF). Using 123 I metaiodobenzylguanidine ( 123 I-MIBG) scintigraphy, we investigated whether a cardiac sympathetic nervous system (SNS) abnormality would be associated with an increased risk of vascular events in patients with paroxysmal AF. 123 I-MIBG scintigraphy was performed in 69 consecutive patients (67 ± 13 years, 62% men) with paroxysmal AF who did not have structural heart disease. SNS integrity was assessed from the heart to mediastinum (H/M) ratio on delayed imaging. Serum concentration of C-reactive protein (CRP) was measured before 123 I-MIBG study. During a mean of 4.5 ± 3.6 years follow-up, 19 patients had myocardial infarction, stroke or heart failure (range: 0.2-11.5 years). SNS abnormality (H/M ratio <2.7) and high CRP (≥0.3 mg/dl) were associated with the vascular events (58.3% in 14 of 24 patients with SNS abnormality vs 11.1% in 5 of 45 patients without SNS abnormality, p < 0.0001, 52.4% in 11 of 21 patients with high CRP vs 16.7% in 8 of 48 patients without high CRP, p < 0.0001). After adjustment for potential confounding variables such as age, left atrial dimension and left ventricular function, SNS abnormality was an independent predictor of vascular events with a hazard ratio of 4.1 [95% confidence interval (CI): 1.3-12.6, p = 0.014]. Further, SNS abnormality had an incremental and additive prognostic power in combination with high CRP with an adjusted hazard ratio of 4.1 (95% CI: 1.5-10.9, p = 0.006). SNS abnormality is predictive of vascular events in patients with idiopathic paroxysmal AF. (orig.)
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Energy Technology Data Exchange (ETDEWEB)
Akutsu, Yasushi; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Kawamura, Mitsuharu; Asano, Taku; Hamazaki, Yuji; Tanno, Kaoru; Kobayashi, Youichi [Showa University School of Medicine, Division of Cardiology, Department of Medicine, Tokyo (Japan); Suyama, Jumpei; Shinozuka, Akira; Gokan, Takehiko [Showa University School of Medicine, Department of Radiology, Tokyo (Japan)
2010-04-15
Neuronal system activity plays an important role for the prognosis of patients with atrial fibrillation (AF). Using {sup 123}I metaiodobenzylguanidine ({sup 123}I-MIBG) scintigraphy, we investigated whether a cardiac sympathetic nervous system (SNS) abnormality would be associated with an increased risk of vascular events in patients with paroxysmal AF. {sup 123}I-MIBG scintigraphy was performed in 69 consecutive patients (67 {+-} 13 years, 62% men) with paroxysmal AF who did not have structural heart disease. SNS integrity was assessed from the heart to mediastinum (H/M) ratio on delayed imaging. Serum concentration of C-reactive protein (CRP) was measured before {sup 123}I-MIBG study. During a mean of 4.5 {+-} 3.6 years follow-up, 19 patients had myocardial infarction, stroke or heart failure (range: 0.2-11.5 years). SNS abnormality (H/M ratio <2.7) and high CRP ({>=}0.3 mg/dl) were associated with the vascular events (58.3% in 14 of 24 patients with SNS abnormality vs 11.1% in 5 of 45 patients without SNS abnormality, p < 0.0001, 52.4% in 11 of 21 patients with high CRP vs 16.7% in 8 of 48 patients without high CRP, p < 0.0001). After adjustment for potential confounding variables such as age, left atrial dimension and left ventricular function, SNS abnormality was an independent predictor of vascular events with a hazard ratio of 4.1 [95% confidence interval (CI): 1.3-12.6, p = 0.014]. Further, SNS abnormality had an incremental and additive prognostic power in combination with high CRP with an adjusted hazard ratio of 4.1 (95% CI: 1.5-10.9, p = 0.006). SNS abnormality is predictive of vascular events in patients with idiopathic paroxysmal AF. (orig.)
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Energy Technology Data Exchange (ETDEWEB)
Tripathi, Alok M., E-mail: alokmani@iitb.ac.in; Mitra, Sagar
2016-11-15
Graphical abstract: Destabilization of graphene oxide colloid and SnS graphene composite preparation for lithium-ion battery. - Abstract: Tin mono sulfide (SnS) graphene composite has been synthesized for anode of lithium-ion battery. For synthesis of composite, graphene oxide (GO)-water (H{sub 2}O) colloid has been destabilized and ensured the complete transfer of graphene oxide into another organic solvent N, N-dimethyl formamide (DMF). Mechanism for the destabilization of GO-H{sub 2}O colloid is established. Surface to surface attachment of SnS on graphene sheet is achieved by solvothermal solution phase assembly of graphene sheets and SnS nanoparticles in DMF solvent. Graphene plays role in nanoparticle formation in composite. Such confined composite has been cycled reversibly at current rate of 160 mA g{sup −1}, in voltage region of 0.01–2.5 V and exhibit a superior discharge capacity of 630 mAh g{sup −1} after 50th cycle. Ex situ TEM analysis of used electrode reveal that the SnS nanoparticle-graphene composite with CMC binder perform better due to proper shape retention of electroactive materials during electrochemical cycling.
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International Nuclear Information System (INIS)
Tripathi, Alok M.; Mitra, Sagar
2016-01-01
Graphical abstract: Destabilization of graphene oxide colloid and SnS graphene composite preparation for lithium-ion battery. - Abstract: Tin mono sulfide (SnS) graphene composite has been synthesized for anode of lithium-ion battery. For synthesis of composite, graphene oxide (GO)-water (H_2O) colloid has been destabilized and ensured the complete transfer of graphene oxide into another organic solvent N, N-dimethyl formamide (DMF). Mechanism for the destabilization of GO-H_2O colloid is established. Surface to surface attachment of SnS on graphene sheet is achieved by solvothermal solution phase assembly of graphene sheets and SnS nanoparticles in DMF solvent. Graphene plays role in nanoparticle formation in composite. Such confined composite has been cycled reversibly at current rate of 160 mA g"−"1, in voltage region of 0.01–2.5 V and exhibit a superior discharge capacity of 630 mAh g"−"1 after 50th cycle. Ex situ TEM analysis of used electrode reveal that the SnS nanoparticle-graphene composite with CMC binder perform better due to proper shape retention of electroactive materials during electrochemical cycling.
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Grain size and lattice parameter's influence on band gap of SnS thin nano-crystalline films
Energy Technology Data Exchange (ETDEWEB)
Gupta, Yashika [Department of Electronics, S.G.T.B. Khalsa College, University of Delhi, Delhi 110007 (India); Department of Electronic Science, University of Delhi-South Campus, New Delhi 110021 (India); Arun, P., E-mail: arunp92@physics.du.ac.in [Department of Electronics, S.G.T.B. Khalsa College, University of Delhi, Delhi 110007 (India); Naudi, A.A.; Walz, M.V. [Facultad de Ingeniería, Universidad Nacional de Entre Ríos, 3101 Oro Verde (Argentina); Albanesi, E.A. [Facultad de Ingeniería, Universidad Nacional de Entre Ríos, 3101 Oro Verde (Argentina); Instituto de Física del Litoral (CONICET-UNL), Guemes 3450, 3000 Santa Fe (Argentina)
2016-08-01
Tin sulphide nano-crystalline thin films were fabricated on glass and Indium Tin Oxide (ITO) substrates by thermal evaporation method. The crystal structure orientation of the films was found to be dependent on the substrate. Residual stress existed in the films due to these orientations. This stress led to variation in lattice parameter. The nano-crystalline grain size was also found to vary with film thickness. A plot of band-gap with grain size or with lattice parameter showed the existence of a family of curves. This implied that band-gap of SnS films in the preview of the present study depends on two parameters, lattice parameter and grain size. The band-gap relation with grain size is well known in the nano regime. Experimental data fitted well with this relation for the given lattice constants. The manuscript uses theoretical structure calculations for different lattice constants and shows that the experimental data follows the trend. Thus, confirming that the band gap has a two variable dependency. - Highlights: • Tin sulphide films are grown on glass and ITO substrates. • Both substrates give differently oriented films. • The band-gap is found to depend on grain size and lattice parameter. • Using data from literature, E{sub g} is shown to be two parameter function. • Theoretical structure calculations are used to verify results.
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Thermal study of a cryogen-less MgB{sub 2} cavity
Energy Technology Data Exchange (ETDEWEB)
Holzbauer, J.P., E-mail: jeremiah@fnal.gov; Nassiri, A.
2014-12-11
Recent efforts towards production of high-quality magnesium diboride (MgB{sub 2}) coatings have raised the possibility of producing usable accelerating cavities. Work continues to reliably produce films of sufficient quality over the large, complex surface area of an accelerating cavity, but this technology would open many interesting technical opportunities. One of these is to replace the traditionally required liquid helium cryogenic systems with a dry system based on cryocoolers. This is made possible by the much higher T{sub c} of MgB{sub 2}, allowing operation closer to 30 K where cryocooler efficiency becomes competitive with alternative systems. This removes the need for pressure vessels in the cryomodule as well as internal distribution systems, greatly simplifying cryomodule design and fabrication. The lack of uniform cooling over the cavity surface, however, complicates behavior by coupling RF losses, heat leak, and cooling design in a way not seen in traditional SRF cavities. In this paper, these complexities are explored, including realistic cryocooler performance, temperature dependant RF losses, and standard thermal management challenges.
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Final Commissioning of the Superconducting Heavy Ion Linear Accelerator at IUAC, Delhi
Datta, Tripti Sekhar; Choudhury, Anup; Chacko, Jacob; Kar, Soumen; Antony, Joby; Babu, Suresh; Kumar, Manoj; Mathuria, D. S.; Sahu, Santosh; Kanjilal, Dinakar
The superconducting linac as a booster of the 15UD Pelletron accelerator was partly commissioned with one linac module housing eight quarter wave bulk niobium cavities along with the superbuncher and rebuncher cryomodules. Subsequently two more linac cryomodules were added to have in total 24 cavities for acceleration. In addition, a new Linde helium refrigerator of capacity 750 W @ 4.2 K was installed in parallel to the earlier CCI refrigerator. The new refrigerator was integrated with the earlier cryogenics network system through a specially designed liquid helium distribution line without any valve box. The cooling philosophy with this new system is modified to have a faster cool down rate in the critical zone (150 - 70 K) to avoid Q disease. The helium gas pressure fluctuation in the cavities is reduced significantly to have stable RF locking. The full linac is being operated and beams with higher energy are being delivered to the users. The present paper will highlight the performance of the new cryogenic system with respect to cool down rate, and helium pressure fluctuation.
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International Nuclear Information System (INIS)
Peng, Quanling; Xu, Fengyu; Wang, Ting; Yang, Xiangchen; Chen, Anbin; Wei, Xiaotao; Gao, Yao; Hou, Zhenhua; Wang, Bing; Chen, Yuan; Chen, Haoshu
2014-01-01
A batch superconducting solenoid magnet for the ADS proton linear accelerator has been designed, fabricated, and tested in a vertical dewar in Sept. 2013. A total of ten superconducting magnets will be installed into two separate cryomodules. Each cryomodule contains six superconducting spoke RF cavities for beam acceleration and five solenoid magnets for beam focusing. The multifunction superconducting magnet contains a solenoid for beam focusing and two correctors for orbit correction. The design current for the solenoid magnet is 182 A. A quench performance test shows that the operating current of the solenoid magnet can reach above 300 A after natural quenching on three occasions during current ramping (260 A, 268 A, 308 A). The integrated field strength and leakage field at the nearby superconducting spoke cavities all meet the design requirements. The vertical test checked the reliability of the test dewar and the quench detection system. This paper presents the physical and mechanical design of the batch magnets, the quench detection technique, field measurements, and a discussion of the residual field resulting from persistent current effects
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Operational experiences of the spallation neutron source superconducting linac and power ramp-up
International Nuclear Information System (INIS)
Kim, Sang-Ho
2009-01-01
The spallation neutron source (SNS) is a second generation pulsed neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the commissioning of the accelerator complex in 2006, the SNS has started its operation for neutron production and beam power ramp-up has been in progress toward the design goal. All subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators because the design beam power is almost an order of magnitude higher compared to existing neutron facilities and the achievable neutron scattering performance will exceed present sources by more than a factor of 20 to 100. In this paper, the operational experiences with the SNS Superconducting Linac (SCL), Power Ramp-up Plan to reach the design goal and the Power Upgrade Plan (PUP) will be presented including machine, subsystem and beam related issues.
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Chiu, ChingChe J; Young, Sean D
2015-06-01
Social networking technologies have emerged as potential platforms to reach HIV(+) MSM in HIV interventions. This study sought to compare use of online social networking sites (SNSs) and sexual risk behaviors between HIV(+) and HIV(-) individuals among a sample of predominately African American and Latino SNS-using MSM. A total of 112 MSM Facebook users were recruited online and offline and completed an online survey. We performed regression models to assess the association between HIV status, SNS use, and sexual risk behaviors. After adjusting for age, race, and employment status, being HIV positive was significantly associated with a greater number of sexual partners (ARR = 2.84, p = 0.0017) and lower comfort levels of discussing HIV/STI status on SNSs (AOR: 0.23, p = 0.011). Findings suggest that HIV status is associated with sexual risk behaviors and SNS use among SNS-using MSM. We discuss the implications for online HIV prevention.
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Casagrande, F.; Fila, A.; Nguyen, C.; Tatsumoto, H.
2017-12-01
The Facility for Rare Isotope Beams (FRIB) will be a scientific user facility for the Office of Nuclear Physics in the U.S. Department of Energy Office of Science (DOE-SC). The FRIB linear accelerator (LINAC) will be comprised of cryomodules each with multiple Superconducting Radio Frequency (SRF) cavities operating at 2 K. A helium refrigeration system was designed, fabricated, installed and commissioned in the SRF high bay building to test and certify these cavities and cryomodules before installation in the FRIB LINAC tunnel. The helium refrigeration system includes a helium refrigerator which has nominal capacity of 900 W at 4 K, 5000 L liquid helium storage Dewar, helium gas storage, two room temperature vacuum pumps capable of 2.5 g/s each for 2 K testing, purifier, purifier recovery compressor, and the distribution system for liquid nitrogen and helium. The helium refrigeration system is now operational supporting three below grade cavity testing Dewars and one cryomodule testing bunker meeting the required throughput of 1 cavity per day.
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International Nuclear Information System (INIS)
Camilleri, Gail; Borg Grima, Karen; Zarb, Francis
2012-01-01
Purpose: The sentinel lymph node biopsy (SLNB) concept using the cutaneous (subdermal) peri-areolar approach is rapidly emerging as the technique for axillary staging in breast cancer. The procedure indicates whether axillary lymph node dissection (ALND) is necessary, therefore drastically minimising the invasiveness of surgical treatment. The SLNB concept is based on evidence suggesting that malignant disease primarily affects the sentinel node (SN) before being disseminated into the axillary lymph nodes (ALNs). Objective: This study was to define the role of lymphoscintigraphy in the visualisation of SNs during SLNB and to establish the correlation between the number of SNs identified on lymphoscintigraphy to the number of surgically identified SNs. Method: The study was a non-experimental, correlation study utilising quantitative data. Lymphoscintigraphy reports and histology results of 55 female breast cancer patients who underwent SLNB with partial or total back-up ALND, were retrospectively evaluated. Results: A maximum of 2 and a minimum of 0 sentinel nodes were visualised on lymphoscintigraphy in 52 out of 55 patients. Successful lymphoscintigraphy was highly predictive (p ≤ 0.001) of a successful SLNB as all 52 patients (94.5%) proceeded to have successful SN/s identification. There was a significant association (p ≤ 0.05) between the number of SN/s visualised on lymphoscintigraphy and the number of SN/s identified during SLNB. Lymphoscintigraphy accurately predicted the number of surgically identified SNs in 50.91% of cases (28/55). Conclusion: Considering that successful imaging effectively assures SN identification, the routine use of lymphoscintigraphy using the subdermal peri-areolar approach is fundamental in the reliable performance of SLNB.
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Social Networking Sites, Depression, and Anxiety: A Systematic Review
Kern, Margaret L; Rickard, Nikki S
2016-01-01
Background Social networking sites (SNSs) have become a pervasive part of modern culture, which may also affect mental health. Objective The aim of this systematic review was to identify and summarize research examining depression and anxiety in the context of SNSs. It also aimed to identify studies that complement the assessment of mental illness with measures of well-being and examine moderators and mediators that add to the complexity of this environment. Methods A multidatabase search was performed. Papers published between January 2005 and June 2016 relevant to mental illness (depression and anxiety only) were extracted and reviewed. Results Positive interactions, social support, and social connectedness on SNSs were consistently related to lower levels of depression and anxiety, whereas negative interaction and social comparisons on SNSs were related to higher levels of depression and anxiety. SNS use related to less loneliness and greater self-esteem and life satisfaction. Findings were mixed for frequency of SNS use and number of SNS friends. Different patterns in the way individuals with depression and individuals with social anxiety engage with SNSs are beginning to emerge. Conclusions The systematic review revealed many mixed findings between depression, anxiety, and SNS use. Methodology has predominantly focused on self-report cross-sectional approaches; future research will benefit from leveraging real-time SNS data over time. The evidence suggests that SNS use correlates with mental illness and well-being; however, whether this effect is beneficial or detrimental depends at least partly on the quality of social factors in the SNS environment. Understanding these relationships will lead to better utilization of SNSs in their potential to positively influence mental health. PMID:27881357
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Perceptions of Pediatric Residents Regarding Counseling About Use of Social Networking Sites.
Banker, Sumeet L; Fenick, Ada M; Qin, Li; Talwalkar, Jaideep S
2018-04-01
Increasing use of social networking sites (SNS) among youth prompted professional organizations to urge pediatricians to promote healthy media use. Electronic questionnaires were distributed to 76 pediatric residents at one academic center measuring attitudes, practices, and familiarity with SNS. Of 43 respondents (response rate = 57%), most reported personal SNS use (98%) and familiarity with SNS used by youth (72%), and 88% agreed that pediatricians should provide counseling on SNS use. Only 5% felt they had adequate training on SNS use in children, and just 26% felt comfortable advising families. Residents were less likely to discuss SNS use than general media use (19% vs 56%, P = .007). Media counseling was correlated with SNS counseling ( r = .38, P = .01). Pediatric residents recognize the importance of guiding families on SNS use, yet do not routinely provide counseling despite high levels of personal SNS use and familiarity. Focused training is necessary for pediatricians to prioritize practical guidance.
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Tomiguchi, Mai; Yamamoto-Ibusuki, Mutsuko; Yamamoto, Yutaka; Fujisue, Mamiko; Shiraishi, Shinya; Inao, Touko; Murakami, Kei-ichi; Honda, Yumi; Yamashita, Yasuyuki; Iyama, Ken-ichi; Iwase, Hirotaka
2016-02-01
Single-photon emission computed tomography (SPECT)/computed tomography (CT) improves the anatomical identification of sentinel lymph nodes (SNs). We aimed to evaluate the possibility of predicting the SN status using SPECT/CT. SN mapping using a SPECT/CT system was performed in 381 cases of clinically node-negative, operable invasive breast cancer. We evaluated and compared the values of SN mapping on SPECT/CT, the findings of other modalities and clinicopathological factors in predicting the SN status. Patients with SNs located in the Level I area were evaluated. Of the 355 lesions (94.8 %) assessed, six cases (1.6 %) were not detected using any imaging method. According to the final histological diagnosis, 298 lesions (78.2 %) were node negative and 83 lesions (21.7 %) were node positive. The univariate analysis showed that SN status was significantly correlated with the number of SNs detected on SPECT/CT in the Level I area (P = 0.0048), total number of SNs detected on SPECT/CT (P = 0.011), findings of planar lymphoscintigraphy (P = 0.011) and findings of a handheld gamma probe during surgery (P = 0.012). According to the multivariate analysis, the detection of multiple SNs on SPECT/CT imaging helped to predict SN metastasis. The number of SNs located in the Level I area detected using the SPECT/CT system may be a predictive factor for SN metastasis.
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Zhao, Bing; Yang, Yaqing; Wang, Zhixuan; Huang, Shoushuang; Wang, Yanyan; Wang, Shanshan; Chen, Zhiwen; Jiang, Yong
2018-02-01
SnS is widely studied as anode materials since of its superior structural stability and physicochemical property comparing with other Sn-based composites. Nevertheless, the inconvenience of phase morphology control and excessive consumption of sulfur sources during synthesis hinder the scalable application of SnS nanocomposites. Herein, we report a facile in-situ sulfuration strategy to synthesize sandwiched spherical SnS/sulfur-doped graphene (SnS/S-SG) composite. An ultra-low sulfur content with approximately stoichiometric ratio of Sn:S can effectively promote the sulfuration reaction of SnO2 to SnS and simultaneous sulfur-doping of graphene. The as-prepared SnS/S-SG composite shows a three-dimensional interconnected spherical structure as a whole, in which SnS nanoparticles are sandwiched between the multilayers of graphene sheets forming a hollow sphere. The sandwiched sphere structure and high S doping amount can improve the binding force between SnS and graphene, as well as the structural stability and electrical conductivity of the composite. Thus, a high reversibility of conversion reaction, promising specific capacity (772 mAh g-1 after 100 cycles at 0.1 C) and excellent rate performance (705 and 411 mAh g-1 at 1 C and 10 C, respectively) are exhibited in the SnS/S-SG electrode, which are much higher than that of the SnS/spherical graphene synthesized by traditional post-sulfuration method.
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International Nuclear Information System (INIS)
A. Hutton; D. Arenius; J. Benesch; S. Chattopadhyay; E. F. Daly; O. Garza; R. Kazimi; R. Lauzi; L. Merminga; W. Merz; R. Nelson; W. Oren; M. Poelker; P. Powers; J. Preble; V. Ganni; C. R. Reece; R. Rimmer; M. Spata; S. Suhring
2004-01-01
Hurricane Isabel, originally a Category 5 storm, arrived at Jefferson Lab on September 18, 2003 with winds of only 75 mph, creating little direct damage to the infrastructure. However, electric power was lost for four days allowing the superconducting cryomodules to warm up and causing a total loss of the liquid helium. The subsequent recovery of the cryomodules and the impact of the considerable amount of opportunistic preventive maintenance provides important lessons for all accelerator complexes, not only those with superconducting elements. The details of how the recovery process was structured and the resulting improvement in accelerator availability will be discussed in detail
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Utz, S.; Beukeboom, C.J.
2011-01-01
On social network sites (SNS), information about one's romantic partner is readily available and public for friends. The paper focuses on the negative (SNS jealousy) and positive (SNS relationship happiness) consequences of SNS use for romantic relationships. We examined whether relationship satisfaction, trait jealousy, SNS use and need for popularity predicted these emotional consequences of SNS use and tested the moderating role of self-esteem. For low self-esteem individuals, need for pop...
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Non-vacuum mechanochemical route to the synthesis of Cu2SnS3 nano-ink for solar cell applications
International Nuclear Information System (INIS)
Vanalakar, S.A.; Agawane, G.L.; Shin, S.W.; Yang, H.S.; Patil, P.S.; Kim, J.Y.; Kim, J.H.
2015-01-01
Cu-based ternary chalcogenides such as Cu 2 SnS 3 (CTS) are attracting increasing interest due to their outstanding opto-electronic properties. Herein, a simple, cost-effective non-vacuum mechanochemical synthetic route for preparing CTS nanocrystals with controlled size and composition is presented. CTS nanocrystalline powders were synthesized by ball milling and subsequent annealing in an H 2 S atmosphere. These nanocrystal samples were characterized using powder X-ray diffraction (P-XRD), Raman spectroscopy, ultraviolet–visible optical spectroscopy, energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques. Texture structures with cubic crystallinity were observed from the P-XRD of (1 1 2), (2 0 0) planes of CTS nanopowders. The EDS results confirmed that the synthesized powders had an appropriate chemical purity. According to TEM/FE-SEM observations, a nanostructure CTS was obtained after 36 h of mechanochemical processing followed by annealing. The average particle size of single phase CTS after 48 h of milling was ∼45 nm. Based on obtained data using characterization methods, reaction mechanism steps were proposed to clarify the reactions that occurred during the mechanochemical process. In order to prepare nanocrystal ink, ethanol was used as a solvent, and polyvinylpyrrolidone, which acts as an organic stabilizing agent, was added to the CTS powder to prepare a printable paste
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Toma, Tania; Athanasiou, Thanos; Harling, Leanne; Darzi, Ara; Ashrafian, Hutan
2014-11-01
Social networking services (SNS) can facilitate real-time communication and feedback of blood glucose and other physiological data between patients and healthcare professionals. This systematic review and meta-analysis aims to summarise the current evidence surrounding the role of online social networking services in diabetes care. We performed a systematic literature review of the Medline, EMBASE and PsychINFO databases of all studies reporting HbA1c (glycated haemoglobin) as a measure of glycaemic control for social networking services in diabetes care. HbA1c, clinical outcomes and the type of technology used were extracted. Study quality and publication bias were assessed. SNS interventions beneficially reduced HbA1c when compared to controls, which was confirmed by sensitivity analysis. SNS interventions also significantly improved systolic and diastolic blood pressure, triglycerides and total cholesterol. Subgroup analysis according to diabetes type demonstrated that Type 2 diabetes patients had a significantly greater reduction in HbA1c than those with Type 1 diabetes. Online SNS provide a novel, feasible approach to improving glycaemic control, particularly in patients with Type 2 diabetes. Further mechanistic and cost-effectiveness studies are required to improve our understanding of SNS and its efficacy in diabetes care. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
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Converter-Modulator Design and Operations for the ILC L-band Test Stand
Energy Technology Data Exchange (ETDEWEB)
Reass, William A.; /Los Alamos; Burkhart, C.; Adolphsen, Chris E.; Beukers, T.; Cassel, R.; de Lira, A.; Papas, C.; Nguyen, M.; Went, R.; /SLAC; Anderson, David E.; /Oak
2007-09-10
To facilitate a rapid response to the International Linear Collider (ILC) L-band development program at SLAC, a spare converter-modulator was shipped from LANL. This modulator was to be a spare for the spallation neutron source (SNS) accelerator at ORNL. The ILC application requires a 33% higher peak output power (15 MW) and output current (120 Amp). This presents significant design challenges to modify the existing hardware and yet maintain switching parameters and thermal cycling within the semiconductor component ratings. To minimize IGBT commutation and free-wheeling diode currents, a different set of optimizations, as compared to the SNS design, were used to tune the resonant switching networks. Additional complexities arose as nanocrystalline cores with different performance characteristics (as compared to SNS), were used to fabricate the resonant 'boost' transformers. This paper will describe the electrical design, modeling efforts, and resulting electrical performance as implemented for the ILC L-band test stand.
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Clark, David J; Chatterjee, Sudeshna A; McGuirk, Theresa E; Porges, Eric C; Fox, Emily J; Balasubramanian, Chitralakshmi K
2018-02-01
Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist scoring of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities-specific Balance Confidence Scale, respectively. There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. Published by Elsevier B.V.
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Social Networking Sites, Depression, and Anxiety: A Systematic Review.
Seabrook, Elizabeth M; Kern, Margaret L; Rickard, Nikki S
2016-11-23
Social networking sites (SNSs) have become a pervasive part of modern culture, which may also affect mental health. The aim of this systematic review was to identify and summarize research examining depression and anxiety in the context of SNSs. It also aimed to identify studies that complement the assessment of mental illness with measures of well-being and examine moderators and mediators that add to the complexity of this environment. A multidatabase search was performed. Papers published between January 2005 and June 2016 relevant to mental illness (depression and anxiety only) were extracted and reviewed. Positive interactions, social support, and social connectedness on SNSs were consistently related to lower levels of depression and anxiety, whereas negative interaction and social comparisons on SNSs were related to higher levels of depression and anxiety. SNS use related to less loneliness and greater self-esteem and life satisfaction. Findings were mixed for frequency of SNS use and number of SNS friends. Different patterns in the way individuals with depression and individuals with social anxiety engage with SNSs are beginning to emerge. The systematic review revealed many mixed findings between depression, anxiety, and SNS use. Methodology has predominantly focused on self-report cross-sectional approaches; future research will benefit from leveraging real-time SNS data over time. The evidence suggests that SNS use correlates with mental illness and well-being; however, whether this effect is beneficial or detrimental depends at least partly on the quality of social factors in the SNS environment. Understanding these relationships will lead to better utilization of SNSs in their potential to positively influence mental health. ©Elizabeth M Seabrook, Margaret L Kern, Nikki S Rickard. Originally published in JMIR Mental Health (http://mental.jmir.org), 23.11.2016.
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Social networking in Bangladesh: Boon or curse for academic engagement?
Mouri Dey; Ali Arshad Chowdhury
2016-01-01
The number of social networking services (SNSs) users in Bangladesh is increasing at an accelerating rate. There are many who argue that SNS usage is destroying the students’ future by diminishing their academic engagement. The authors aim to investigate whether there is any relationship between students’ academic performance and their SNS usage. The study chose Facebook as a representative of SNSs because this is the most popular platform for online social connectivity and conducted a survey...
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First cold test of TESLA superconducting RF cavity in horizontal cryostat (CHECHIA)
International Nuclear Information System (INIS)
Kuzminski, J.
1996-01-01
In the framework of the TESLA project, the horizontal cryostat (CHECHIA) was built to test a superconducting RF cavity equipped with its helium vessel, magnetic shielding, cold tuner, main coupler and higher order modes couplers under realistic conditions before final assembly of eight cavities into TESLA Test Facility cryo-module. The results of the first cold tests in CHECHIA, performed at DESY with a 9-cell cavity (C19) to be used in the TTF injector are presented. (author)
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Directory of Open Access Journals (Sweden)
Sara Santarossa
2017-05-01
Full Text Available The aim of this study was to investigate whether problematic social networking site (SNS use (i.e., degree of dependent relationship with SNSs, total SNS time/day, total SNS friends, and specific SNS activities were related to body image (BI, self-esteem (SE, and eating disorder (ED symptoms/concerns. A sample of young adults ( N = 147 completed an online survey which measured SNS usage, problematic SNS use, BI, SE, and ED symptom/concerns. The findings revealed that females and males spent 4.1 ± 3.9 and 2.9 ± 2.8 hr on SNS, respectively, with the majority of time spent lurking (i.e., looking at another users’ profile but not actually communicating with them. Furthermore, problematic SNS use was found to be related to BI, SE, and ED symptoms/concerns. Moreover, SNS activities, such as lurking and posting comments on others’ profiles, were found to be related to BI, whereas SNS total time was found to be related to ED symptoms/concerns. Overall, this study demonstrates the possible correlational influence of SNSs on BI, SE, and ED symptoms/concerns.
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Directory of Open Access Journals (Sweden)
IMRAN ANWAR MIR
2018-04-01
Full Text Available Social media has produced substantial changes in the communication landscape. Online social network sites (SNS grew as a common platform for online social interaction. SNS firms generate revenue from the advertising appearing on SNS. Their survival depends on users’ approval of such social network advertising (SNA. Marketing literature indicates that users accept advertising if it is consistent with their motivations for using social media. Information seeking is the most recognized SNS motivation. Yet, research on evaluating the influence of SNS information motivation on users’ approval of SNA is scarce. Based on SNS uses and gratifications theory, this study proposes a multidimensional model that shows the influence of SNS information motivation on users’ approval of SNA.
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Commissioning of the helium cryogenic system for the HIE- ISOLDE accelerator upgrade at CERN
International Nuclear Information System (INIS)
Delruelle, N; Inglese, V; Leclercq, Y; Pirotte, O; Williams, L
2015-01-01
The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN. The most significant improvement will come from replacing the existing REX accelerating structure by a superconducting linear accelerator (SC linac) composed ultimately of six cryo-modules installed in series, each containing superconducting RF cavities and solenoids operated at 4.5 K. In order to provide the cooling capacity at all temperature levels between 300 K and 4.5 K for the six cryo-modules, an existing helium refrigerator, manufactured in 1986 and previously used to cool the ALEPH magnet during LEP operation from 1989 to 2000, has been refurbished, reinstalled and recommissioned in a dedicated building located next to the HIE-ISOLDE experimental hall. This helium refrigerator has been connected to a new cryogenic distribution line, consisting of a 30-meter long vacuum-insulated transfer line, a 2000-liter storage dewar and six interconnecting valve boxes, one for each cryo-module. This paper describes the whole cryogenic system and presents the commissioning results including the preliminary operation at 4.5 K of the first cryo- module in the experimental hall. (paper)
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A long-wavelength target station for the spallation neutron source
International Nuclear Information System (INIS)
Carpenter, J.M.; Mason, T.E.
2005-01-01
The Spallation Neutron Source (SNS), a major new user facility for studies of the structure and dynamics of materials, funded by the US Department of Energy (DOE), is under construction at Oak Ridge National Laboratory (ORNL). Details about the project are available in a recent paper and on the SNS Web site [MRS Bull. 28 (12) (2003) 923]. A Long-Wavelength Target Station (LWTS) [Technical Concepts for a Long-Wavelength Target Station for the Spallation Neutron Source, Argonne National Laboratory Report ANL-02/16, Oak Ridge National Laboratory Report ORNL/SNS-TM-2001/163, November 2002. See also www.pns.anl.gov/related/] will complement the High-Power Target Station (HPTS) facility of the SNS and will build upon the significant investment in the remainder of the installation by providing important new scientific opportunities. For areas of science using the optimized long-wavelength beam lines, the LWTS will at least double the overall scientific capability of the SNS and provide for up to an order of magnitude performance gain over the initial HPTS. The fully equipped SNS has the prospect to offer capabilities for neutron-scattering studies of the structure and dynamics of materials with sensitivity, resolution, dynamic range, and speed that are unparalleled in the world. Preliminary assessments of the performance of the several instruments treated in detail in the body of the paper bear out this expectation. The LWTS concept has been developed in close consultation with the scientific community through a series of workshops and conferences jointly sponsored by DOE's Office of Basic Energy Science and the National Science Foundation. We describe the principal features of the LWTS concept, and provide a preliminary summary of some neutron scattering instruments suited to exploit the unique features of the LWTS. It remains to develop concepts and designs for a full suite of instruments that exploit the capabilities of LWTS, a process that has begun in collaboration
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International Nuclear Information System (INIS)
Yamashita, Koji
2010-01-01
I have studied endoscopic surgery for breast diseases and 3-dimensional (3D) computed tomographic (CT) lymphography for sentinel node (SN) biopsy. In this second in a series of reports, I explain the techniques of 3D-CT lymphography. 3D-CT lymphography can show the detailed lymphatic flow from the breast tumor toward the SNs and the exact local relation between axillary lymph nodes. I have developed this 3D image-processing system to more precisely depict the anatomical structures of the mammary lymphovascular system. This system allows us to systematically collect axillary lymph nodes, including SNs. 3D-CT lymphography was performed to mark SNs on the skin on the day before surgery. Above the tumor and near the areola, 2 ml of Iopamiron 300 was injected subcutaneously. Sixteen-channel multidetector-row helical CT scan images were obtained 1 minute after injection to detect SNs, and after 3 and 5 minutes to observe lymph flow into the venous angle. The scan images were reconstructed to produce 3D images. SN biopsy was performed with the dye-staining method and endoscopy. 3D-CT lymphography accurately showed lymphatic flow from the tumor to SNs. We classified the relationship between the lymph ducts and the drained SNs into 4 patterns. Following up 3 and 5 minutes after injection of the contrast agent, we can follow the lymph ducts beyond the SN into the second and third nodes toward the venous angle with the complex plexus. The figure of the axillary nodes shows 5 beads-like grouped nodes. 3D-CT lymphography can also recognize the metastatic patterns of the enhanced lymph node. These patterns will predict the metastasis before SN biopsy. 3D-CT lymphography can also be used to detect lymph flow from the arm to avoid harming the arm lymph channel during axillary node dissection and SN biopsy. With 3D-CT lymphography, we can more accurately and precisely recognize lymph flow and the positional relations of SN and axillary nodes to surrounding anatomical structures
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Utz, S.; Beukeboom, C.J.
2011-01-01
On social network sites (SNS), information about one's romantic partner is readily available and public for friends. The paper focuses on the negative (SNS jealousy) and positive (SNS relationship happiness) consequences of SNS use for romantic relationships. We examined whether relationship
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Dark currents for CEBAF linacs
International Nuclear Information System (INIS)
Yunn, B.C.
1995-01-01
Continuing on our numerical study of field emitted electrons from a superconducting CEBAF cavity we have identified all possible emission sites, magnitudes, and the energy profile of dark currents expected at CEBAF under nominal operating conditions. We find that most electrons do not survive beyond a single cryomodule which includes eight 5-cell superconducting cavities. However, some electrons can be accelerated through many cryomodules, ending up with an energy close to 100 MeV. However, no field emitted electrons can be recirculated along with an electron beam generated at the gun, due to the limited energy acceptance of CEBAF recirculation arcs. 4 refs., 4 figs
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Jones, Jamal; Salazar, Laura F
2016-11-01
This review describes the use of social networking sites (SNS) in the context of primary prevention of HIV. A review was conducted to assess the published literature for HIV interventions using SNS. Sixteen articles describing twelve interventions were included. SNS were instrumental in recruiting hard-to-reach populations within a short amount of time; were able to reach wide audiences beyond the targeted population for HIV prevention campaigns; and helped to significantly reduce sexual risk behaviors and increase HIV testing. SNS are a viable option to recruit hidden populations, engage the target audience, and disseminate HIV prevention messages. Researchers should use SNS to generate sampling frames that can be used to select participants. Practitioners should use SNS to post images of preventive behavior within health promotion campaigns. Researchers should use multiple SNS platforms to engage participants. As more studies are published using SNS for HIV prevention, meta-analyses will be needed.
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An 'open source' networked identity
DEFF Research Database (Denmark)
Larsen, Malene Charlotte
2013-01-01
This paper examines the concept of identity in relation to youth practices on social network sites (SNS). The paper illustrates how writing “I love you” or other emotional statements on each other’s profiles on SNS is not only a common way for Danish teenagers to communicate and practice friendship...... communicative actions – are not only performing their own identity, but are becoming co-constructors of each other's identities, which the author characterizes as an 'open source' networked identity....
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Seltzer, Erica D; Stolley, Melinda R; Mensah, Edward K; Sharp, Lisa K
2014-09-01
The recent and rapid growth of social networking site (SNS) use presents a unique public health opportunity to develop effective strategies for the recruitment of hard-to-reach participants for cancer research studies. This survey investigated childhood cancer survivors' reported use of SNS such as Facebook or MySpace and their perceptions of using SNS, for recruitment into survivorship research. Sixty White, Black, and Hispanic adult childhood cancer survivors (range 18-48 years of age) that were randomly selected from a larger childhood cancer study, the Chicago Healthy Living Study, participated in this pilot survey. Telephone surveys were conducted to understand current SNS activity and attitudes towards using SNS as a cancer research recruitment tool. Seventy percent of participants reported SNS usage of which 80 % were at least weekly users and 79 % reported positive attitudes towards the use of SNS as a recruitment tool for survivorship research. The results of this pilot study revealed that SNS use was high and regular among the childhood cancer survivors sampled. Most had positive attitudes towards using SNS for recruitment of research. The results of this pilot survey suggest that SNS may offer an alternative approach for recruitment of childhood cancer survivors into research.
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Seltzer, Erica D.; Stolley, Melinda R.; Mensah, Edward K.; Sharp, Lisa K.
2014-01-01
Purpose The recent and rapid growth of social networking site (SNS) use presents a unique public health opportunity to develop effective strategies for the recruitment of hard-to-reach participants for cancer research studies. This survey investigated childhood cancer survivors’ reported use of SNS such as facebook or MySpace and their perceptions of using SNS, for recruitment into survivorship research. Methods Sixty White, Black and Hispanic, adult childhood cancer survivors (range 18 – 48 years of age) that were randomly selected from a larger childhood cancer study, the Chicago Healthy Living Study (CHLS), participated in this pilot survey. Telephone surveys were conducted to understand current SNS activity and attitudes towards using SNS as a cancer research recruitment tool. Results Seventy percent of participants reported SNS usage of which 80% were at least weekly users and 79 % reported positive attitudes towards the use of SNS as a recruitment tool for survivorship research. Conclusions and implications for cancer survivors The results of this pilot study revealed that SNS use was high and regular among the childhood cancer survivors sampled. Most had positive attitudes towards using SNS for recruitment of research. The results of this pilot survey suggest that SNS may offer an alternative approach for recruitment of childhood cancer survivors into research. PMID:24532046
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Nitzburg, George C; Farber, Barry A
2013-11-01
Social networking sites (SNS) like Facebook can increase interpersonal connections but also intensify jealousy, envy, and surveillance behaviors. Attachment styles may help explain differences in experiencing SNS. This study investigated the role of attachment in influencing emerging adults' perceptions and feelings about SNS and their disclosures on SNS. Disorganized and anxious attachment predicted subjects' use of SNS to avoid more personal face-to-face communication, suggesting individuals with these tendencies use SNS to hold relationships at a psychological arm's distance. Anxious attachment also predicted feelings of intimacy when using SNS, perhaps reflecting online needs for comfort from others. A case narrative is presented to show how those with insecure attachment patterns may struggle to avoid interpersonal conflict when being continuously presented with ambiguous social information. © 2013 Wiley Periodicals, Inc.
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Karpinski, Aryn; Kirschner, Paul A.; Ozer, Ipek; Mellott, Jennifer; Ochwo, Pius
2018-01-01
Studies have shown that multitasking with technology, specifically using Social Networking Sites (SNSs), decreases both efficiency and productivity in an academic setting. This study investigates multitasking’s impact on the relationship between SNS use and Grade Point Average (GPA) in United
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Al Asari, S; Meurette, G; Mantoo, S; Kubis, C; Wyart, V; Lehur, P-A
2014-11-01
The study assessed the initial experience with posterior tibial nerve stimulation (PTNS) for faecal incontinence and compared it with sacral nerve stimulation (SNS) performed in a single centre during the same timespan. A retrospective review of a prospectively collected database was conducted at the colorectal unit, University Hospital, Nantes, France, from May 2009 to December 2010. Seventy-eight patients diagnosed with chronic severe faecal incontinence underwent neurostimulation including PTNS in 21 and SNS in 57. The main outcome measures were faecal incontinence (Wexner score) and quality of life (Fecal Incontinence Quality of Life, FIQL) scores in a short-term follow-up. No significant differences were observed in patients' characteristics. Of 57 patients having SNS, 18 (32%) failed peripheral nerve evaluation and 39 (68%) received a permanent implant. Two (5%) developed a wound infection. No adverse effects were recorded in the PTNS group. There was no significant difference in the mean Wexner and FIQL scores between patients having PTNS and SNS at 6 (P = 0.39 and 0.09) and 12 months (P = 0.79 and 0.37). A 50% or more improvement in Wexner score was seen at 6 and 12 months in 47% and 30% of PTNS patients and in 50% and 58% of SNS patients with no significant difference between the groups. Posterior tibial nerve stimulation is a valid method of treating faecal incontinence in the short term when conservative treatment has failed. It is easier, simpler, cheaper and less invasive than SNS with a similar short-term outcome. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.
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Cryogenic system for the Energy Recovery Linac and vertical test facility at BNL
International Nuclear Information System (INIS)
Than, R.; Soria, V.; Lederle, D.; Orfin, P.; Porqueddu, R.; Talty, P.; Zhang, Y.; Tallerico, T.; Masi, L.
2011-01-01
A small cryogenic system and warm helium vacuum pumping system provides cooling to either the Energy Recovery Linac's (ERL) cryomodules that consist of a 5-cell cavity and an SRF gun or a large Vertical Test Dewar (VTD) at any given time. The cryogenic system consists of a model 1660S PSI piston plant, a 3800 liter storage dewar, subcooler, a wet expander, a 50 g/s main helium compressor, and a 170 m 3 storage tank. A system description and operating plan of the cryogenic plant and cryomodules is given. The cryogenic system for ERL and the Vertical Test Dewar has a plant that can produce the equivalent of 300W at 4.5K with the addition of a wet expander 350 W at 4.5K. Along with this system, a sub-atmospheric, warm compression system provides pumping to produce 2K at the ERL cryomodules or the Vertical Test Dewar. The cryogenic system for ERL and the Vertical Test Dewar makes use of existing equipment for putting a system together. It can supply either the ERL side or the Vertical Test Dewar side, but not both at the same time. Double valve isolation on the liquid helium supply line allows one side to be warmed to room temperature and worked on while the other side is being held at operating temperature. The cryogenic system maintain the end loads from 4.4K to 2K or colder depending on capacity. Liquid helium storage dewar capacity allows ERL or the VTD to operate above the plant's capacity when required and ERL cryomodules ballast reservoirs and VTD reservoir allows the end loads to operate on full vacuum pump capacity when required.
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Hall, Jeffrey A
2014-05-01
Abstract Although social networking sites (SNS) have become increasingly prevalent and integrated into the lives of users, the role of SNS in courtship is relatively unknown. The present manuscript reports on the characteristics of Americans married between 2005 and 2012 who met through SNS drawn from a weighted national sample (N=18,527). Compared to other online meetings (i.e., dating sites, online communities, one-on-one communication), individuals who met through SNS were younger, married more recently, and were more likely to be African American. Compared with offline meetings, individuals who met through SNS were more likely to be younger, male, African American and Hispanic, married more recently, and frequent Internet users with higher incomes. Trends suggest an increasing proportion of individuals are meeting using SNS, necessitating further research on factors that influence romantic relational development through SNS.
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Utz, Sonja; Breuer, Johannes
2017-01-01
Existing work on the effects of social network sites (SNS) on well-being has often stressed that SNS can help people gain social support from their online networks, which positively affects their well-being. However, the majority of studies in this area have been cross-sectional in nature and/or relied on student samples. Using data from six waves of a longitudinal study with a representative sample of Dutch Internet users, we first examined whether users and nonusers of SNS differ in online social support and well-being (as indicated by life satisfaction and stress). In a second step, we investigated in more detail how SNS use - more specifically, asking for advice and the number of strong ties on these SNS - are related to online social support, stress, and satisfaction with life. Overall, our results provide no evidence for SNS use and online social support affecting either stress or life satisfaction. SNS users reported more online social support than nonusers did, but also higher levels of stress; the two groups did not differ in overall life satisfaction. With regard to the underlying processes, we found positive cross-sectional and longitudinal relationships between asking for advice on SNS and online social support, indicating that SNS can be an effective tool for receiving social support. However, online social support was not related to higher life satisfaction or reduced stress 6 months later; instead, it seems that SNS users with lower life satisfaction and/or higher stress seek more social support online by asking for advice on SNS.
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Pontes, Halley M; Taylor, Megan; Stavropoulos, Vasileios
2018-04-01
The use of social networking sites (SNSs) is rapidly increasing as billions of individuals use SNS platforms regularly to communicate with other users, follow the news, and play browser games. Given the widespread use of SNS platforms, investigating the potential predictors of addictive SNS use beyond Facebook use has become paramount given that most studies so far focused on "Facebook addiction." In this study, a total of 511 English-speaking SNS users (58.1% young adults aged 20-35 years; 64.6% female) were recruited online and asked to complete a battery of standardized psychometric tools assessing participants' sociodemographic characteristics, SNS preferences and patterns of use, SNS addiction, preference for online social interaction, maladaptive cognitions, fear of missing out (FoMo), dysfunctional emotion regulation, and general psychiatric distress. Overall, about 4.9% (n = 25) of all participants could be classed as having a high SNS addiction risk profile. Moreover, the results further indicated that FoMo (β = 0.38), maladaptive cognitions (β = 0.25), and psychiatric distress (β = 0.12) significantly predicted SNS addiction (i.e., p < 0.0001) and accounted for about 61% of the total variance in SNS addiction, with FoMo providing the strongest predictive contribution over and above the effects of sociodemographic variables and patterns of SNS use. The implications of the present findings were discussed in light of extant literature on behavioral addictions and Facebook addiction and further considerations were provided regarding the potential clinical implications for cognitive-based psychological treatment approaches to SNS addiction.
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The Relationship Between Use of Social Network Sites, Online Social Support, and Well-Being
2017-01-01
Abstract. Existing work on the effects of social network sites (SNS) on well-being has often stressed that SNS can help people gain social support from their online networks, which positively affects their well-being. However, the majority of studies in this area have been cross-sectional in nature and/or relied on student samples. Using data from six waves of a longitudinal study with a representative sample of Dutch Internet users, we first examined whether users and nonusers of SNS differ in online social support and well-being (as indicated by life satisfaction and stress). In a second step, we investigated in more detail how SNS use – more specifically, asking for advice and the number of strong ties on these SNS – are related to online social support, stress, and satisfaction with life. Overall, our results provide no evidence for SNS use and online social support affecting either stress or life satisfaction. SNS users reported more online social support than nonusers did, but also higher levels of stress; the two groups did not differ in overall life satisfaction. With regard to the underlying processes, we found positive cross-sectional and longitudinal relationships between asking for advice on SNS and online social support, indicating that SNS can be an effective tool for receiving social support. However, online social support was not related to higher life satisfaction or reduced stress 6 months later; instead, it seems that SNS users with lower life satisfaction and/or higher stress seek more social support online by asking for advice on SNS. PMID:29147141
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Characterization of the Shielded Neutron Source at Triangle Universities Nuclear Laboratory
Hobson, Chad; Finch, Sean; Howell, Calvin; Malone, Ron; Tornow, Wernew
2016-09-01
In 2015, Triangle Universities Nuclear Laboratory rebuilt its shielded neutron source (SNS) with the goal of improving neutron beam collimation and reducing neutron and gamma-ray backgrounds. Neutrons are produced via the 2H(d,n)3He reaction and then collimated by heavy shielding to form a beam. The SNS has the ability to produce both a rectangular and circular neutron beam through use of two collimators with different beam apertures. Our work characterized both the neutron beam profiles as well as the neutron and gamma-ray backgrounds at various locations around the SNS. This characterization was performed to provide researchers who use the SNS with beam parameters necessary to plan and conduct an experiment. Vertical and horizontal beam profiles were measured at two different distances from the neutron production cell by scanning a small plastic scintillator across the face of the beam at various energies for each collimator. Background neutron and gamma-ray intensities were measured using time-of-flight techniques at 10 MeV and 16 MeV with the rectangular collimator. We present results on the position and size of neutron beam as well as on the structure and magnitude of the backgrounds.
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Brisson, Gregory E; Fisher, Matthew J; LaBelle, Mark W; Kozmic, Sarah E
2015-01-01
Use of social networking sites (SNS) by medical students is increasing, and some students lack awareness of pitfalls arising from the intersection of social networking and medicine. Many institutions have developed guidelines on using SNS, but they are insufficient for students. Educators need new methods to train students on the appropriate use of this technology, but more information is needed before implementing change. Differences in SNS usage between students and faculty were examined. The goal was to evaluate four content areas: SNS usage patterns, attitudes regarding activity on SNS, experience with patient interactions online, and awareness of institutional guidelines on use of SNS. A cross-sectional survey took place at Feinberg School of Medicine, Northwestern University, in 2012. Participants included all students and a cohort of faculty who teach them in a class on professionalism. The response rate was 42% by students (300/711) and 78% by faculty (31/40). Of the students, 94% use SNS, compared to 48% of faculty. Students were more likely than faculty to display content they would not want patients to see (57% vs. 27%), report seeing inappropriate content on colleagues' SNS profiles (64% vs. 42%), and ignore harmful postings by colleagues (25% vs. 7%). Faculty were more likely than students to have been approached by patients on SNS (53% vs. 3%). Most participants were unlikely to conduct Internet searches on patients. Students are more likely than faculty to use SNS and use it very differently than faculty. Students would benefit from training on appropriate use of SNS. Topics that should be addressed include editing one's online presence, managing friend requests from patients, dealing with colleagues who post harmful content, conducting Internet searches on patients, and discussion of boundaries to identify potential harms associated with SNS usage. Differences in usage between students and faculty raise questions if faculty are well suited to
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The Effect of Loneliness on Social Networking Sites Use and Its Related Behaviors.
Ranaeiy, Samira; Taghavi, Mohammad Reza; Goodarzi, Mohammad Ali
2016-08-01
The current research was conducted to examine the effect of "Loneliness", on time spent in Social Networking Sites (S.N.S), main reasons for S.N.S use, and its related behaviors. 156 students of Shiraz University voluntarily participated in this research. Loneliness was assessed usingthe UCLA Loneliness scale. 25% of highest scoring students reported that they were lonely whereas 25% of the lowest scoring students were considered to be non-lonely. The positive and negative reasons of using S.N.S were assessed based on Reasons for Internet Use Scale, and internet behaviors were assessed based on Scale of Internet Behaviors. There was no difference in time spent in S.N.S as well as the positive and negative reasons of using S.N.S (contrary to literature), but internet behaviors showed a significant difference between "lonely" and "non-lonely" individuals. "Lonely" and "non-lonely" individuals showed a significant difference in "social aspect" of S.N.S behaviors. There was also a significant difference between "Lonely" and "non-Lonely" individuals in "Negative impact" of S.N.S behaviors. Yet, there seemed to be no difference in "competency and convenience aspect" of S.N.S behaviors. This study suggested that there is no difference between lonely and non-lonely individuals in reasons for using S.N.S and time spent in S.N.S. This finding stands contrary to previous research findings and general literature on the subject In other words, what drives people to S.N.S at the first place shows no significant difference between lonely and non-lonely individuals while after attending S.N.S, social behavior of lonely individuals shows a significant difference which is consistently enhanced online. Lonely people also significantly develop internet-related problems in their daily functioning, including interference with real life socializing.
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An FFAG-ERL at Cornell University for eRHIC prototyping and bright-beam applications
Energy Technology Data Exchange (ETDEWEB)
Hoffstaetter, Georg [Cornell University, Ithaca, NY (United States)
2016-07-01
Cornell University has prototyped technology essential for any high-brightness electron ERL. This includes a DC gun and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current CW cryomodule for 70 MeV energy gain, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams, e.g. slid measurements for 6-D phase-space densities, a fast wire scanner for beam profiles, and beam loos diagnostics. All these are now available to equip a one-cryomodule ERL, and laboratory space has been cleared out and is radiation shielded to install this ERL at Cornell. BNL has designed a multi-turn ERL for eRHIC, where beam is transported more than 20 times around the RHIC tunnel. The number of transport lines is minimized by using two non-scaling (NS) FFAG arcs. A collaboration between BNL and Cornell has been formed to investigate the new NS-FFAG optics and the multi-turn eRHIC ERL design by building a 4-turn, one-cryomodule ERL at Cornell. It has a NS-FFAG return loop built with permanent magnets and is meant to accelerate 40 mA beam to 250 MeV.
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Sentinel node lymphoscintigraphy in breast cancer: problems, solutions and clinical utility
International Nuclear Information System (INIS)
Wye, D.A.; Cohn, D.; Evans, S.G.; Larcos, G.; Ung, O.; Barry, P.
1999-01-01
Full text: Axillary lymph node status is an essential element in the staging of breast cancer. Recently, lymphatic mapping and sentinel node (SN) identification with lymphoscintigraphy has been promoted. The purposes of this study were to determine: (1) factors important in optimal identification of SNs preoperatively and (2) accuracy of SNs in predicting axillary lymph node status. Lymphoscintigraphy using 99 Tc m -antimony trisulphide colloid was performed in 35 patients before axillary dissection surgery. Four injections (20 MBq in 0.5 ml) were administered either around the biopsy cavity/scar or peritumorally. Sequential images in the anterior, anterior oblique and lateral projections were obtained until a SN was identified and in some patients delayed images (up to 15 h) were required. SNs were marked on the patient's skin in two planes. During surgery, a hand-held gamma probe was used to localize the marked SNs, which were removed prior to complete axillary dissection. Dissected lymph nodes were evaluated histopathologically for tumour involvement. To optimize SN identification, we found that breast cleaning post-injection, breast massage, imaging with arms both raised and lowered, and using different symbols to mark multiple SNs were necessary. In 32/35 patients (91%), a SN was successfully identified. Drainage patterns varied and were primarily to the axilla, internal mammary chain and intra clavicular areas. The SN appears to be an accurate predictor of axillary node status. In conclusion, breast lymphoscintigraphy is a simple procedure which appears to accurately identify sentinel nodes
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Billedo, Cherrie Joy; Kerkhof, Peter; Finkenauer, Catrin
2015-03-01
Social networking sites (SNS) play an increasingly important role in maintaining geographically close romantic relationships (GCRR). However, knowledge about SNS use in long-distance romantic relationships (LDRR) is still lacking. The present study examined the relative importance of SNS in maintaining LDRR compared to GCRR, particularly with regard to the use of SNS to express involvement (via relational maintenance behaviors) and to gauge a partner's involvement (via partner surveillance and jealousy) in the relationship. An online survey was conducted among predominantly young adult Facebook users who were in a romantic relationship (N=272). Results showed that participants who were in a LDRR reported higher levels of relational maintenance behaviors through SNS than participants who were in a GCRR. Also, as compared to participants who were in a GCRR, participants who were in a LDRR used SNS more for partner surveillance and experienced higher levels of SNS jealousy.
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Park, Bu Kyung; Calamaro, Christina
2013-09-01
To review the evidence to determine if social networking sites (SNS) are effective tools for health research in the adolescent and young adult populations. Systematic review of published research articles focused on use of SNS for youth health research. Seventeen articles were selected that met the following criteria: used SNS at any stage of study, participants between 13 and 25 years of age, English language, and both international and national studies. Reviewers categorized selected studies based on the way SNS were used. Utilization of SNS for effectively implementing research with adolescents and young adults include (a) recruitment, (b) intervention, and (c) measurement. Four findings about advantages of using SNS apparent in this review are (a) ease of access to youth, (b) cost effectiveness in recruitment, (c) ease of intervention, and (d) reliable screening venue of mental status and high-risk behaviors. Although this literature review showed relatively minimal research to date on the use of SNS for research targeting adolescents and young adults, the impact of using SNS for health research is of considerable importance for researchers as well as participants. With careful focus, SNS can become a valuable platform to access, recruit, and deliver health interventions in a cost-effective manner to youth populations as well as hard-to-reach minority or underserved populations. The evidence demonstrates the usefulness of SNS as innovative platforms for health promotion among adolescents and young adults. © 2013 Sigma Theta Tau International.