Pub Date : 2009-10-01Print Date: 2009-09-01DOI: 10.6028/jres.114.018
Giovanni Garberoglio, Allan H Harvey
Knowledge of the pair and three-body potential-energy surfaces of helium is now sufficient to allow calculation of the third density virial coefficient, C(T), with significantly smaller uncertainty than that of existing experimental data. In this work, we employ the best available pair and three-body potentials for helium and calculate C(T) with path-integral Monte Carlo (PIMC) calculations supplemented by semiclassical calculations. The values of C(T) presented extend from 24.5561 K to 10 000 K. In the important metrological range of temperatures near 273.16 K, our uncertainties are smaller than the best experimental results by approximately an order of magnitude, and the reduction in uncertainty at other temperatures is at least as great. For convenience in calculation of C(T) and its derivatives, a simple correlating equation is presented.
现在对氦的对体和三体势能面的了解已经足以计算第三密度维里系数 C(T),其不确定性大大小于现有的实验数据。在这项工作中,我们采用了现有最好的氦对和三体势能,并通过路径积分蒙特卡罗(PIMC)计算,辅以半经典计算,计算出了 C(T)。在靠近 273.16 K 的重要计量温度范围内,我们的不确定性比最佳实验结果小大约一个数量级,而在其他温度下,不确定性的减小至少同样大。为了方便计算 C(T) 及其导数,我们给出了一个简单的相关方程。
{"title":"First-Principles Calculation of the Third Virial Coefficient of Helium.","authors":"Giovanni Garberoglio, Allan H Harvey","doi":"10.6028/jres.114.018","DOIUrl":"10.6028/jres.114.018","url":null,"abstract":"<p><p>Knowledge of the pair and three-body potential-energy surfaces of helium is now sufficient to allow calculation of the third density virial coefficient, C(T), with significantly smaller uncertainty than that of existing experimental data. In this work, we employ the best available pair and three-body potentials for helium and calculate C(T) with path-integral Monte Carlo (PIMC) calculations supplemented by semiclassical calculations. The values of C(T) presented extend from 24.5561 K to 10 000 K. In the important metrological range of temperatures near 273.16 K, our uncertainties are smaller than the best experimental results by approximately an order of magnitude, and the reduction in uncertainty at other temperatures is at least as great. For convenience in calculation of C(T) and its derivatives, a simple correlating equation is presented.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646577/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-01Print Date: 2009-09-01DOI: 10.6028/jres.114.019
K A Gillis, H Lin, M R Moldover
We examine the perturbations of the modes of an acoustic thermometer caused by circular ducts used either for gas flow or as acoustic waveguides coupled to remote transducers. We calculate the acoustic admittance of circular ducts using a model based on transmission line theory. The admittance is used to calculate the perturbations to the resonance frequencies and half-widths of the modes of spherical and cylindrical acoustic resonators as functions of the duct's radius, length, and the locations of the transducers along the duct's length. To verify the model, we measured the complex acoustic admittances of a series of circular tubes as a function of length between 200 Hz and 10 kHz using a three-port acoustic coupler. The absolute magnitude of the specific acoustic admittance is approximately one. For a 1.4 mm inside-diameter, 1.4 m long tube, the root mean square difference between the measured and modeled specific admittances (both real and imaginary parts) over this frequency range was 0.018. We conclude by presenting design considerations for ducts connected to acoustic thermometers.
{"title":"Perturbations From Ducts on the Modes of Acoustic Thermometers.","authors":"K A Gillis, H Lin, M R Moldover","doi":"10.6028/jres.114.019","DOIUrl":"https://doi.org/10.6028/jres.114.019","url":null,"abstract":"<p><p>We examine the perturbations of the modes of an acoustic thermometer caused by circular ducts used either for gas flow or as acoustic waveguides coupled to remote transducers. We calculate the acoustic admittance of circular ducts using a model based on transmission line theory. The admittance is used to calculate the perturbations to the resonance frequencies and half-widths of the modes of spherical and cylindrical acoustic resonators as functions of the duct's radius, length, and the locations of the transducers along the duct's length. To verify the model, we measured the complex acoustic admittances of a series of circular tubes as a function of length between 200 Hz and 10 kHz using a three-port acoustic coupler. The absolute magnitude of the specific acoustic admittance is approximately one. For a 1.4 mm inside-diameter, 1.4 m long tube, the root mean square difference between the measured and modeled specific admittances (both real and imaginary parts) over this frequency range was 0.018. We conclude by presenting design considerations for ducts connected to acoustic thermometers.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646578/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34353629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-01Print Date: 2009-07-01DOI: 10.6028/jres.114.015
A K Gaigalas, Lili Wang, Hua-Jun He, Paul DeRose
This work describes a procedure for acquiring a spectrum of an analyte over an extended range of wavelengths and validating the wavelength and intensity assignments. To acquire a spectrum over an extended range of wavelengths with a spectrometer with a charge coupled device (CCD) array detector, it is necessary to acquire many partial spectra, each at a different angular position of the grating, and splice the partial spectra into a single extended spectrum. The splicing procedure exposes instrument dependent artifacts. It is demonstrated that by taking a spectrum of a reference irradiance source and making spectral correction, the artifacts exposed by the splicing are removed from the analyte spectrum. This is because the irradiance reference spectrum contains the same artifacts as the analyte spectrum. The artifacts exposed by the splicing depend on the wavelength of the splice; therefore it is important to measure the irradiance reference spectrum for the same range of wavelengths used to measure the spectrum of the analyte solution. In other words, there is no general spectral correction factor which is applicable to spectra taken for different range of wavelengths. The wavelength calibration is also carried out by splicing many partial spectra from a source like a krypton lamp. However the wavelength assignments are not sensitive to the splicing procedure and the same wavelength calibration can be used for spectra acquired over different extended wavelength ranges. The wavelength calibration checks the validity of the setting of the grating angular position, and the assignment of wavelengths to individual pixels on the CCD array detector. The procedure is illustrated by measuring the spectrum of an orange glass and the spectrum of a suspension of microalgae.
{"title":"Procedures for Wavelength Calibration and Spectral Response Correction of CCD Array Spectrometers.","authors":"A K Gaigalas, Lili Wang, Hua-Jun He, Paul DeRose","doi":"10.6028/jres.114.015","DOIUrl":"https://doi.org/10.6028/jres.114.015","url":null,"abstract":"<p><p>This work describes a procedure for acquiring a spectrum of an analyte over an extended range of wavelengths and validating the wavelength and intensity assignments. To acquire a spectrum over an extended range of wavelengths with a spectrometer with a charge coupled device (CCD) array detector, it is necessary to acquire many partial spectra, each at a different angular position of the grating, and splice the partial spectra into a single extended spectrum. The splicing procedure exposes instrument dependent artifacts. It is demonstrated that by taking a spectrum of a reference irradiance source and making spectral correction, the artifacts exposed by the splicing are removed from the analyte spectrum. This is because the irradiance reference spectrum contains the same artifacts as the analyte spectrum. The artifacts exposed by the splicing depend on the wavelength of the splice; therefore it is important to measure the irradiance reference spectrum for the same range of wavelengths used to measure the spectrum of the analyte solution. In other words, there is no general spectral correction factor which is applicable to spectra taken for different range of wavelengths. The wavelength calibration is also carried out by splicing many partial spectra from a source like a krypton lamp. However the wavelength assignments are not sensitive to the splicing procedure and the same wavelength calibration can be used for spectra acquired over different extended wavelength ranges. The wavelength calibration checks the validity of the setting of the grating angular position, and the assignment of wavelengths to individual pixels on the CCD array detector. The procedure is illustrated by measuring the spectrum of an orange glass and the spectrum of a suspension of microalgae.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.6028/jres.114.015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-01Print Date: 2009-07-01DOI: 10.6028/jres.114.017
Herbert S Bennett, Howard Andres, Joan Pellegrino
In 2006, the National Institute of Standards and Technology conducted an assessment of the U.S. measurement system (USMS), which encompasses all private and public organizations that develop, supply, use, or ensure the validity of measurement results. As part of that assessment, NIST collaborated with Energetics Incorporated to identify and authenticate 723 measurement needs that are barriers to technological innovations. A number of these measurement needs (64) are relevant to accelerating innovation and commercialization of nano-electrotechnologies. In this paper, we apply the taxonomy from a 2008 international survey that established a global consensus of priorities for standards and measurements in nano-electrotechnologies to rank in priority order the relevant 64 USMS-identified measurement needs. This paper presents a method for assigning priorities that is statistically based and represents a global consensus of stakeholders. Such a method is needed because limited resources exist to address the large number of measurement needs in nano-electrotechnologies, and the most critical measurement needs should be addressed first.
2006年,美国国家标准与技术研究所(National Institute of Standards and Technology)对美国测量系统(USMS)进行了评估,该系统涵盖了所有开发、供应、使用或确保测量结果有效性的私营和公共组织。作为评估的一部分,NIST与Energetics公司合作,确定并验证了723种测量需求,这些需求是技术创新的障碍。这些测量需求中的许多(64)与加速纳米电子技术的创新和商业化有关。在本文中,我们应用2008年国际调查的分类,该调查建立了纳米电子技术标准和测量的全球优先共识,以优先顺序排列相关的64个美国科学院确定的测量需求。本文提出了一种分配优先级的方法,该方法基于统计并代表了利益相关者的全球共识。这种方法是必要的,因为现有的资源有限,无法满足纳米电技术中大量的测量需求,而最关键的测量需求应该首先得到解决。
{"title":"A Method for Assigning Priorities to United States Measurement System (USMS) Needs: Nano-Electrotechnologies.","authors":"Herbert S Bennett, Howard Andres, Joan Pellegrino","doi":"10.6028/jres.114.017","DOIUrl":"https://doi.org/10.6028/jres.114.017","url":null,"abstract":"<p><p>In 2006, the National Institute of Standards and Technology conducted an assessment of the U.S. measurement system (USMS), which encompasses all private and public organizations that develop, supply, use, or ensure the validity of measurement results. As part of that assessment, NIST collaborated with Energetics Incorporated to identify and authenticate 723 measurement needs that are barriers to technological innovations. A number of these measurement needs (64) are relevant to accelerating innovation and commercialization of nano-electrotechnologies. In this paper, we apply the taxonomy from a 2008 international survey that established a global consensus of priorities for standards and measurements in nano-electrotechnologies to rank in priority order the relevant 64 USMS-identified measurement needs. This paper presents a method for assigning priorities that is statistically based and represents a global consensus of stakeholders. Such a method is needed because limited resources exist to address the large number of measurement needs in nano-electrotechnologies, and the most critical measurement needs should be addressed first.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651608/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-01Print Date: 2009-07-01DOI: 10.6028/jres.114.016
Paul R Garabedian, Geoffrey B McFadden
Runs of the NSTAB nonlinear stability code show there are many three-dimensional (3D) solutions of the advanced tokamak problem subject to axially symmetric boundary conditions. These numerical simulations based on mathematical equations in conservation form predict that the ITER international tokamak project will encounter persistent disruptions and edge localized mode (ELMS) crashes. Test particle runs of the TRAN transport code suggest that for quasineutrality to prevail in tokamaks a certain minimum level of 3D asymmetry of the magnetic spectrum is required which is comparable to that found in quasiaxially symmetric (QAS) stellarators. The computational theory suggests that a QAS stellarator with two field periods and proportions like those of ITER is a good candidate for a fusion reactor. For a demonstration reactor (DEMO) we seek an experiment that combines the best features of ITER, with a system of QAS coils providing external rotational transform, which is a measure of the poloidal field. We have discovered a configuration with unusually good quasisymmetry that is ideal for this task.
{"title":"Design of the DEMO Fusion Reactor Following ITER.","authors":"Paul R Garabedian, Geoffrey B McFadden","doi":"10.6028/jres.114.016","DOIUrl":"https://doi.org/10.6028/jres.114.016","url":null,"abstract":"<p><p>Runs of the NSTAB nonlinear stability code show there are many three-dimensional (3D) solutions of the advanced tokamak problem subject to axially symmetric boundary conditions. These numerical simulations based on mathematical equations in conservation form predict that the ITER international tokamak project will encounter persistent disruptions and edge localized mode (ELMS) crashes. Test particle runs of the TRAN transport code suggest that for quasineutrality to prevail in tokamaks a certain minimum level of 3D asymmetry of the magnetic spectrum is required which is comparable to that found in quasiaxially symmetric (QAS) stellarators. The computational theory suggests that a QAS stellarator with two field periods and proportions like those of ITER is a good candidate for a fusion reactor. For a demonstration reactor (DEMO) we seek an experiment that combines the best features of ITER, with a system of QAS coils providing external rotational transform, which is a measure of the poloidal field. We have discovered a configuration with unusually good quasisymmetry that is ideal for this task.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651607/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-01Print Date: 2009-07-01DOI: 10.6028/jres.114.014
Shaw C Feng, Che Bong Joung, Theodore V Vorburger
This paper describes a detailed computational model of the interaction between an atomic force microscope probe tip and a sample surface. The model provides analyses of dynamic behaviors of the tip to estimate the probe deflections due to surface intermittent contact and the resulting dimensional biases and uncertainties. Probe tip and cantilever beam responses to intermittent contact between the probe tip and sample surface are computed using the finite element method. Intermittent contacts with a wall and a horizontal surface are computed and modeled, respectively. Using a 75 nm Critical Dimension (CD) tip as an example, the responses of the probe to interaction forces between the sample surface and the probe tip are shown in both time and frequency domains. In particular, interaction forces between the tip and both a vertical wall and a horizontal surface of a silicon sample are modeled using Lennard-Jones theory. The Snap-in and Snap-out of the probe tip in surface scanning are calculated and shown in the time domain. Based on the given tip-sample interaction force model, the calculation includes the compliance of the probe and dynamic forces generated by an excitation. Cantilever and probe tip deflections versus interaction forces in the time domain can be derived for both vertical contact with a plateau and horizontal contact with a side wall. Dynamic analysis using the finite element method and Lennard-Jones model provide a unique means to analyze the interaction of the probe and sample, including calculation of the deflection and the gap between the probe tip and the measured sample surface.
{"title":"Characterization of Probe Dynamic Behaviors in Critical Dimension Atomic Force Microscopy.","authors":"Shaw C Feng, Che Bong Joung, Theodore V Vorburger","doi":"10.6028/jres.114.014","DOIUrl":"https://doi.org/10.6028/jres.114.014","url":null,"abstract":"<p><p>This paper describes a detailed computational model of the interaction between an atomic force microscope probe tip and a sample surface. The model provides analyses of dynamic behaviors of the tip to estimate the probe deflections due to surface intermittent contact and the resulting dimensional biases and uncertainties. Probe tip and cantilever beam responses to intermittent contact between the probe tip and sample surface are computed using the finite element method. Intermittent contacts with a wall and a horizontal surface are computed and modeled, respectively. Using a 75 nm Critical Dimension (CD) tip as an example, the responses of the probe to interaction forces between the sample surface and the probe tip are shown in both time and frequency domains. In particular, interaction forces between the tip and both a vertical wall and a horizontal surface of a silicon sample are modeled using Lennard-Jones theory. The Snap-in and Snap-out of the probe tip in surface scanning are calculated and shown in the time domain. Based on the given tip-sample interaction force model, the calculation includes the compliance of the probe and dynamic forces generated by an excitation. Cantilever and probe tip deflections versus interaction forces in the time domain can be derived for both vertical contact with a plateau and horizontal contact with a side wall. Dynamic analysis using the finite element method and Lennard-Jones model provide a unique means to analyze the interaction of the probe and sample, including calculation of the deflection and the gap between the probe tip and the measured sample surface.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651605/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01Print Date: 2009-05-01DOI: 10.6028/jres.114.010
Lijun Ma, Alan Mink, Xiao Tang
The National Institute of Standards and Technology (NIST) has developed a number of complete fiber-based high-speed quantum key distribution (QKD) systems that includes an 850 nm QKD system for a local area network (LAN), a 1310 nm QKD system for a metropolitan area network (MAN), and a 3-node quantum network controlled by a network manager. This paper discusses the key techniques used to implement these systems, which include polarization recovery, noise reduction, frequency up-conversion detection based on a periodically polled lithium nitrate (PPLN) waveguide, custom high-speed data handling boards and quantum network management. Using our quantum network, a QKD secured video surveillance application has been demonstrated. Our intention is to show the feasibility and sophistication of QKD systems based on current technology.
{"title":"High Speed Quantum Key Distribution Over Optical Fiber Network System.","authors":"Lijun Ma, Alan Mink, Xiao Tang","doi":"10.6028/jres.114.010","DOIUrl":"https://doi.org/10.6028/jres.114.010","url":null,"abstract":"<p><p>The National Institute of Standards and Technology (NIST) has developed a number of complete fiber-based high-speed quantum key distribution (QKD) systems that includes an 850 nm QKD system for a local area network (LAN), a 1310 nm QKD system for a metropolitan area network (MAN), and a 3-node quantum network controlled by a network manager. This paper discusses the key techniques used to implement these systems, which include polarization recovery, noise reduction, frequency up-conversion detection based on a periodically polled lithium nitrate (PPLN) waveguide, custom high-speed data handling boards and quantum network management. Using our quantum network, a QKD secured video surveillance application has been demonstrated. Our intention is to show the feasibility and sophistication of QKD systems based on current technology.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.6028/jres.114.010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34635195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01Print Date: 2009-05-01DOI: 10.6028/jres.114.009
John Jendzurski, Nicholas G Paulter
We examine the measurement uncertainty associated with different methods of calibrating the ubiquitous down-the-road (DTR) radar used in speed enforcement. These calibration methods include the use of audio frequency sources, tuning forks, a fifth wheel attached to the rear of the vehicle with the radar unit, and the speedometer of the vehicle. We also provide an analysis showing the effect of calibration uncertainty on DTR-radar speed measurement uncertainty.
{"title":"Calibration of Speed Enforcement Down-The-Road Radars.","authors":"John Jendzurski, Nicholas G Paulter","doi":"10.6028/jres.114.009","DOIUrl":"https://doi.org/10.6028/jres.114.009","url":null,"abstract":"<p><p>We examine the measurement uncertainty associated with different methods of calibrating the ubiquitous down-the-road (DTR) radar used in speed enforcement. These calibration methods include the use of audio frequency sources, tuning forks, a fifth wheel attached to the rear of the vehicle with the radar unit, and the speedometer of the vehicle. We also provide an analysis showing the effect of calibration uncertainty on DTR-radar speed measurement uncertainty.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.6028/jres.114.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34635194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01Print Date: 2009-05-01DOI: 10.6028/jres.114.012
John W Cooper, Michael A Coplan, Patrick P Hughes
The observation of Lyman alpha (Lα) radiation produced by the end products of the (3)He (n,tp) reaction has suggested the possibility of a new method of cold thermal neutron detection. In order for this goal to be achieved, a basic understanding of how the Lα radiation is formed and how it may be detected, is needed. The model study described here is an attempt to provide this basic understanding and to provide quantitative results that can be used in designing future experiments.
{"title":"The Detection of Lyman Alpha Radiation Formed by the Slowing Down of Protons and Tritons Produced by the (3)He (n, tp) Reaction-A Model Study.","authors":"John W Cooper, Michael A Coplan, Patrick P Hughes","doi":"10.6028/jres.114.012","DOIUrl":"https://doi.org/10.6028/jres.114.012","url":null,"abstract":"<p><p>The observation of Lyman alpha (Lα) radiation produced by the end products of the (3)He (n,tp) reaction has suggested the possibility of a new method of cold thermal neutron detection. In order for this goal to be achieved, a basic understanding of how the Lα radiation is formed and how it may be detected, is needed. The model study described here is an attempt to provide this basic understanding and to provide quantitative results that can be used in designing future experiments.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646570/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34635197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-06-01Print Date: 2009-05-01DOI: 10.6028/jres.114.013
David Gilliam, Stefan Leigh, Andrew Rukhin, William Strawderman
Performance standards for detector systems often include requirements for probability of detection and probability of false alarm at a specified level of statistical confidence. This paper reviews the accepted definitions of confidence level and of critical value. It describes the testing requirements for establishing either of these probabilities at a desired confidence level. These requirements are computable in terms of functions that are readily available in statistical software packages and general spreadsheet applications. The statistical interpretations of the critical values are discussed. A table is included for illustration, and a plot is presented showing the minimum required numbers of pass-fail tests. The results given here are applicable to one-sided testing of any system with performance characteristics conforming to a binomial distribution.
{"title":"Pass-Fail Testing: Statistical Requirements and Interpretations.","authors":"David Gilliam, Stefan Leigh, Andrew Rukhin, William Strawderman","doi":"10.6028/jres.114.013","DOIUrl":"https://doi.org/10.6028/jres.114.013","url":null,"abstract":"<p><p>Performance standards for detector systems often include requirements for probability of detection and probability of false alarm at a specified level of statistical confidence. This paper reviews the accepted definitions of confidence level and of critical value. It describes the testing requirements for establishing either of these probabilities at a desired confidence level. These requirements are computable in terms of functions that are readily available in statistical software packages and general spreadsheet applications. The statistical interpretations of the critical values are discussed. A table is included for illustration, and a plot is presented showing the minimum required numbers of pass-fail tests. The results given here are applicable to one-sided testing of any system with performance characteristics conforming to a binomial distribution.</p>","PeriodicalId":17039,"journal":{"name":"Journal of Research of the National Institute of Standards and Technology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646571/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34646790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}