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1

Absolute measurement of 22Na radioactivity  

International Nuclear Information System (INIS)

Absolute measurement of 22Na radioactivity has been done for the international comparison. The assayed source solution was transferred to NBS type ampoules to send to the SIR (International Reference System) in BIPM, Taiwan and Indonesia, and the rest was sealed in JRIA type ampoules for domestic calibration. The absolute radioactivity of 22Na was obtained by two coincidence methods. One was gamma efficiency variation method, and the other was sum peak gate method based on the positron emission rate. The results of these two methods were in very good agreement. Total activities of the ampoules were assayed relatively with calibrated ionization chambers, and impurity check and also relative measurement was done with a HPGe detector. The results of these two relative methods were in reasonable agreement with the coincidence methods. (author)

2

The absolute measurement of the activity of the radioactive gas  

International Nuclear Information System (INIS)

The paper presents an absolute measurement equipment of the ?-radioactive gas and measured results. After the fixing work of the equipment is done, the electron adsorption effect of the glass isolator surface, the end effect, the wall effect and the absorption effect are carefully measured and researched by 85Kr and 3H. The equipment system error is 0.24% and repeatability is 0.1%. In the measurement, the standard errors of 85Kr and 3H samples are 0.06% and 0.1 respectively. The resultant uncertainty is 0.26%

3

Calibrated radioactive sources - absolute measurements using a 4? ?-? apparatus  

International Nuclear Information System (INIS)

In this paper, the principle of the standardization of the radioisotopes by the 4? ? - ? coincidence method is reminded. Some theoretical examples are given emphasizing on instrumental coincidences and their corrections. The experimental apparatus is described: one discusses the choice of the experimental conditions for the many isotopes measured. Results are given and discussed. In appendix we describe the preparation of the sources. (authors)

4

Calculations of wall effect in proportional counter for absolute radioactivity measurements of gaseous radioisotopes  

International Nuclear Information System (INIS)

Count loss by wall effect was calculated with EGS4 code. Calculated results agreed well with experimental results measured with pressure extrapolation method. In this calculation AE, AP and ECUT, PCUT are better to be set at lower values. Because EGS4 code is not so suited for very low energy of beta-ray, for those samples which emit beta-rays with lower energy than 14C, EGS4 is unsuited to be used for calculation of wall effect. (J.P.N.)

5

Absolute neutrino mass measurements  

International Nuclear Information System (INIS)

The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2?) searches, single ?-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium ?-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope (137Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2? decay and single ?-decay.

6

Absolute measurement of optical attenuation  

International Nuclear Information System (INIS)

We have discovered that laser beam deflection spectroscopy can be used for the absolute measurement of wave or particle beam attenuation in condensed matter. The concept has been experimentally evaluated by successfully measuring the absolute optical attenuation in a crystal of U3+:CaF2 at 514 nm. A theoretical model that explains the experiment and characterizes the range of applicability of the method has been developed

7

Measurement of absolute gamma emission probabilities  

International Nuclear Information System (INIS)

The energies and emission probabilities (intensities) of gamma-rays emitted in radioactive decays of particular nuclides are the most important characteristics by which to quantify mixtures of radionuclides. Often, quantification is limited by uncertainties in measured intensities. A technique was developed to reduce these uncertainties. The method involves obtaining a pure sample of a nuclide using radiochemical techniques, and using appropriate fractions for beta and gamma measurements. The beta emission rates were measured using a liquid scintillation counter, and the gamma emission rates were measured with a high-purity germanium detector. Results were combined to obtain absolute gamma emission probabilities. All sources of uncertainties greater than 0.1% were examined. The method was tested with 38Cl and 88Rb

8

Measurement of absolute gamma emission probabilities  

Energy Technology Data Exchange (ETDEWEB)

The energies and emission probabilities (intensities) of gamma-rays emitted in radioactive decays of particular nuclides are the most important characteristics by which to quantify mixtures of radionuclides. Often, quantification is limited by uncertainties in measured intensities. A technique was developed to reduce these uncertainties. The method involves obtaining a pure sample of a nuclide using radiochemical techniques, and using appropriate fractions for beta and gamma measurements. The beta emission rates were measured using a liquid scintillation counter, and the gamma emission rates were measured with a high-purity germanium detector. Results were combined to obtain absolute gamma emission probabilities. All sources of uncertainties greater than 0.1% were examined. The method was tested with {sup 38}Cl and {sup 88}Rb.

Sumithrarachchi, C.S. E-mail: chandana@nscl.msu.edu; Rengan, Krish; Griffin, H.C

2003-06-01

9

Development of a 4? Liquid Scintillation Counting Method for the Absolute Standardization of Radioactive Solutions with Particular Reference to Efficiency Tracing Measurements  

International Nuclear Information System (INIS)

The liquid scintillation counting method is shown to have special advantages when applied to the absolute standardization of beta emitters by the efficiency tracing technique. The simplicity of producing sources in which the active constituents are uniformly mixed, and the relative insensitivity of the method to physical and chemical effects in the sources are particularly evident. The extrapolation to 100% efficiency (zero energy) is discussed and it is shown that the normal linear extrapolation is not generally valid. The non-linearity is caused by differences in the beta spectra of the two radionuclides but the degree of non-linearity depends on the characteristics of the equipment transforming the beta spectrum into a pulse-height spectrum. For example, some events fail to produce even a single photoelectron at the photocathode and the signals from some others are lost in the noise from the photomultiplier. The number of events so lost depends on the equipment and on circumstances of the measurement, and it is not reasonable to assume that the losses will remain constant unless this can be verified experimentally. Apparatus for investigating these losses is described and its sensitivity to such effects as the non-linearity of scintillant response to beta-particle energy is discussed and shown to be small. The application of the method to routine efficiency tracing measurements is expected to lead to significant improvements in reproducibility and accuracy. (author)

10

Absolute continuity, singularity and product measures  

Directory of Open Access Journals (Sweden)

Full Text Available Conditions are given under which a product of two semifinite measures is absolutely continuous or weakly singular with respect to another product of two semifinite measures. A Lebesgue type decomposition theorem is proved for certain product measures so that the resulting measures are themselves product measures.

Roy A. Johnson

1982-01-01

11

Measuring poverty in Portugal: an absolute approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this article is to measure poverty in Portugal from an absolute perspective. We estimated several absolute poverty lines and defined maximum and minimum thresholds. We applied aggregation measures to these thresholds and constructed probit models to assess the effect of some variables on poverty. The intervals obtained contain the poverty lines constructed by other approaches. We got evidence that poverty is positively correlated with the number of people in the household, with liv...

Pereira, Anto?nio Maria Seabra Moniz

2012-01-01

12

Absolute cross-sections from X-? coincidence measurements  

International Nuclear Information System (INIS)

An activation technique using coincidences between characteristic X-rays and ?-rays to obtain absolute cross-sections is described. This method is particularly useful in the case of nuclei that decay by electron capture. In addition to the reduction of possible contamination, an improved detection sensitivity is achieved as compared to inclusive measurements, thereby allowing the extraction of absolute fusion cross-sections in the nano-barn range. Results of this technique for 6Li+198Pt system, at energies around the Coulomb barrier are described. Future applications with low intensity radioactive ion beams are also discussed.

13

Absolute cross-sections from X-{gamma} coincidence measurements  

Energy Technology Data Exchange (ETDEWEB)

An activation technique using coincidences between characteristic X-rays and {gamma}-rays to obtain absolute cross-sections is described. This method is particularly useful in the case of nuclei that decay by electron capture. In addition to the reduction of possible contamination, an improved detection sensitivity is achieved as compared to inclusive measurements, thereby allowing the extraction of absolute fusion cross-sections in the nano-barn range. Results of this technique for {sup 6}Li+{sup 198}Pt system, at energies around the Coulomb barrier are described. Future applications with low intensity radioactive ion beams are also discussed.

Lemasson, A. [GANIL, CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Shrivastava, A. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Navin, A. [GANIL, CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France)], E-mail: navin@ganil.fr; Rejmund, M. [GANIL, CEA/DSM - CNRS/IN2P3, Bd Henri Becquerel, BP 55027, F-14076 Caen Cedex 5 (France); Nanal, V. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Bhattacharyya, S. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Chatterjee, A.; Kailas, S.; Mahata, K.; Parkar, V.V. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pillay, R.G. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Ramachandran, K.; Rout, P.C. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2009-01-11

14

On Fourier frame of absolutely continuous measures  

CERN Document Server

Let $\\mu$ be a compactly supported absolutely continuous probability measure on ${\\Bbb R}^n$, we show that $\\mu$ admits Fourier frames if and only if its Radon-Nikodym derivative is upper and lower bounded almost everywhere on its support. As a consequence, we prove that if an equal weight absolutely continuous self-similar measure on ${\\Bbb R}^1$ admits Fourier frame, then the measure must be a characteristic function of self-similar tile. In particular, this shows for almost everywhere $1/2<\\lambda<1$, the $\\lambda$-Bernoulli convolutions cannot admit Fourier frames.

Lai, Chun-kit

2011-01-01

15

Precision absolute positional measurement of laser beams.  

Science.gov (United States)

We describe an instrument which, coupled with a suitable coordinate measuring machine, facilitates the absolute measurement within the machine frame of the propagation direction of a millimeter-scale laser beam to an accuracy of around ±4 ?m in position and ±20 ?rad in angle. PMID:23669658

Fitzsimons, Ewan D; Bogenstahl, Johanna; Hough, James; Killow, Christian J; Perreur-Lloyd, Michael; Robertson, David I; Ward, Henry

2013-04-20

16

Absolute-gravity measurements in Europe  

Energy Technology Data Exchange (ETDEWEB)

In 1976 and 1977, 25 absolute-gravity measurements were carried out in 17 stations in Europe with the new transportable apparatus of the Istituto di Metrologia ''G. Colonnetti'', in order to improve the world gravity standard, to begin the study of the scale linearity along the line Hammerfest-Nairobi in IGSN 71 and to establish new absolute references. The uncertainty of the measurements is of the order of 10 ..mu..Gal, about 20 times better than the accuracy of IGSN 71.

Cannizzo, L.; Cerutti, G. (Istituto di Metrologia ' ' G. Colonnetti' ' , Torino (Italy)); Marson, I. (Istituto di Miniere e Geofisica Applicata dell' Universita, Trieste (Italy))

17

Absolute radioactivity measurements of sup 1 sup 5 sup 3 Sm, sup 1 sup 8 sup 8 Re, sup 8 sup 9 Sr and national comparisons  

CERN Document Server

sup 1 sup 5 sup 3 Sm and sup 1 sup 8 sup 8 Re are short half-life nuclides and sup 8 sup 9 Sr is one of pure beta-decay nuclide, these nuclides have being applied to nuclear medicine. It's very important to carry out comparisons for radioactivity standardization of these nuclides. Several laboratories in China including our laboratory took part in the comparisons. The results from our laboratory are in good agreement with the mean values

Wang Jian Qing; Yao Yan Ling; Jia Xue Wen

2003-01-01

18

Absolute measurement of length with nanometric resolution  

Science.gov (United States)

Laser interferometer displacement measuring transducers have a well-defined traceability route to the definition of the meter. The laser interferometer is de-facto length scale for applications in micro and nano technologies. However their physical unit -half lambda is too large for nanometric resolution. Fringe interpolation-usual technique to improve the resolution-lack of reproducibility could be avoided using the principles of absolute distance measurement. Absolute distance refers to the use of interferometric techniques for determining the position of an object without the necessity of measuring continuous displacements between points. The interference pattern as produced by the interference of two point-like coherent sources is fitted to a geometric model so as to determine the longitudinal location of the target by minimizing least square errors. The longitudinal coordinate of the target was measured with accuracy better than 1 nm, for a target position range of 0.4?m.

Apostol, D.; Garoi, F.; Timcu, A.; Damian, V.; Logofatu, P. C.; Nascov, V.

2005-08-01

19

An absolute measure for a key currency  

Science.gov (United States)

It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

20

Absolute measurements of fission cross sections  

International Nuclear Information System (INIS)

Absolute neutron fission cross sections measurements of 235U, 238U and 239Pu have been made at 13.9 and 14.6 MeV with a double 4? ionization chamber. The associated particle method with the time-of-flight technique was used. Our final values of sigma sub(nf)(235U), sigma sub(nf)(238U), sigma sub(nf)(239Pu), sigma sub(nf)(238U)/sigma sub(nf)(235U) and sigma sub(nf)(239Pu)/sigma sub(nf)(235U) are compared to previous data. A sigmasub(nf)(235U) absolute measurement has been made at 2.5 MeV using two references: the scattering cross section of 1H and the directional long counter. Preliminary results is compared to previous data. (author)

 
 
 
 
21

Measurement of absolute gravity acceleration in Firenze  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy. In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0 ?Gal and (980 492 048.3 ± 3.0 ?Gal for the European Laboratory for Non-Linear Spectroscopy (LENS and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

M. de Angelis

2011-01-01

22

Absolute method of measuring magnetic susceptibility  

Science.gov (United States)

An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

Thorpe, A.; Senftle, F.E.

1959-01-01

23

On Absolute Measurements of ?-Emitting Radionuclides  

International Nuclear Information System (INIS)

4 ? GM detectors are described and some of their characteristics presented. The absence of spurious pulses is shown by the measurement of the rate of arrival of intervals between pulses. Some problems related to the foil absorption and source absorption are considered using Sr90 and Y90. Aiming at correcting the counting losses in the foil and in a certain extent also the source absorption an experimental method which uses paired sources is presented. The preparation of standards of Bi210 (RaE) is described. A note is presented on the problem of foil absorption losses in scintillation absolute counting. (author)

24

Airborne measurement of radioactivity  

International Nuclear Information System (INIS)

The German Meteorological Service (Deutscher Wetterdienst, DWD) is responsible for the surveillance of radioactivity in the atmosphere. In case of an radioactive emergency radioactive plumes may be expected in heights up to the tropopause depending on the type of accident. For this reason aircraft measurements are necessary as a supplement to groundbased measuring sites, especially in case of non available details about the source of radioactive release and lack of details about the accident. The authors present an aircraft type Learjet 35A used for localizing radioactive contaminated air masses up to 10,000 m and the measurement of artificial radionuclides on aerosols. For this purpose the aircraft is equipped with an isokinetic high-volume sampler for collection of aerosols on filters outside the pressurized cabin and an onboard gamma spectrometry system with a high purity germanium detector to analyze the interchangeable contaminated filters during flight as well as a dose ratemeter and a GPS (Global Positioning System) for navigation. The collection of gaseous iodine is optional. The meteorological parameters temperature, atmospheric pressure, relative humidity, wind speed and wind direction are determined as well. Resulting data are transmitted by global VHF datalink from the plane to the DWD headquarter and used for verifying the prognosis. (orig.)

25

Absolute measurements of neutron induced reaction rates  

International Nuclear Information System (INIS)

This paper describes techniques for the measurement of neutron-induced reaction rates on an absolute basis. Two main areas of application are discussed: determinations of threshold reactions used to monitor fast fluxes relevant to materials damage and neutron penetration. The accuracy required in these measurements is modest in view of other uncertainties, a standard error of +-10% normally being adequate; determinations of fission and capture rates in zero-power reactors which provide a basis for validation of data and calculation methods applied to the prediction of power reactor performance. Accuracies here are much more stringent, with +-1% on fission rates in the major heavy nuclides and +-0.7% in the capture rate in U-238 being target values based on neutron balance consid

26

Measured and modelled absolute gravity in Greenland  

Science.gov (United States)

Present day changes in the ice volume in glaciated areas like Greenland will change the load on the Earth and to this change the lithosphere will respond elastically. The Earth also responds to changes in the ice volume over a millennial time scale. This response is due to the viscous properties of the mantle and is known as Glaical Isostatic Adjustment (GIA). Both signals are present in GPS and absolute gravity (AG) measurements and they will give an uncertainty in mass balance estimates calculated from these data types. It is possible to separate the two signals if both gravity and Global Positioning System (GPS) time series are available. DTU Space acquired an A10 absolute gravimeter in 2008. One purpose of this instrument is to establish AG time series in Greenland and the first measurements were conducted in 2009. Since then are 18 different Greenland GPS Network (GNET) stations visited and six of these are visited more then once. The gravity signal consists of three signals; the elastic signal, the viscous signal and the direct attraction from the ice masses. All of these signals can be modelled using various techniques. The viscous signal is modelled by solving the Sea Level Equation with an appropriate ice history and Earth model. The free code SELEN is used for this. The elastic signal is modelled as a convolution of the elastic Greens function for gravity and a model of present day ice mass changes. The direct attraction is the same as the Newtonian attraction and is calculated as this. Here we will present the preliminary results of the AG measurements in Greenland. We will also present modelled estimates of the direct attraction, the elastic and the viscous signals.

Nielsen, E.; Forsberg, R.; Strykowski, G.

2012-12-01

27

Absolute flow measurement with orthogonal internal calibration  

International Nuclear Information System (INIS)

Absolute flow measurement with orthogonal calibration was primarily designed for monitoring the percutaneous transluminal angioplasty. The method makes use of the well-known time-of-flight technique for time determinations and an original use of a marker catheter and two orthogonal projections for distance and diameter measurements. The first projection is used to measure the distance and the two orthogonal projections allow very accurate calibration of the vessel diameter. The accuracy of diameter measurements by the authors' methods was compared with that of the classic external calibration. The error of diameter measurement by external calibration can be as high as 24% (for a diameter of 3 mm), whereas with the authors' method this error was reduced to 7%. The authors' method is also independent of enlargement factor, pincushion distortion, and geometric location of the vessel. The accuracy of the method and the influence of the injection settings, distance between the markers, temporal sampling, field-of-view, and enlargement factor were tested with a flow phantom. An accuracy of 91.4% were achieved for a field-of-view of 25 cm and minimal enlargement, while for a 15-cm field-of-view of 25 cm and maximal enlargement the accuracy was improved up to 96.2%. The limiting factors of the authors' method are only the matrix size and the temporal sampling of digital subtraction angiography

28

Airborne measurement of radioactivity  

International Nuclear Information System (INIS)

The following is the description of an aircraft used for localizing and nuclide specific measuring of radioactive contaminated air masses. For this purpose a high-volume collector without a pump for the collection of aerosols by filters, an on board gamma spectrometry system with a high purity germanium detector, a dose ratemeter, a radon daughter monitor and for navigation a global positioning system (GPS) are used. The meteorological parameters temperature, relative humidity and relative wind speed are also determined. The cervice ceiling is 33,000 feet. The resulting measurement data are used for verifying the prognosis made by the Deutscher Wetterdienst. (orig.)

29

Measurement of radioactivity  

International Nuclear Information System (INIS)

Intensive research has been going on in many countries to remove the uncertainties and to develop and perfect the methods of measuring the absolute value of the activity of a radionuclide. The importance of this research would be obvious in the context of the rapidly growing use of radioisotopes all over the world. The use of radionuclides had increased not only in regard to the variety of applications but also in respect of the quantities involved. Until recently these uses had been confined to a few scientifically advanced countries but now they were spreading to more and more countries of the world. Development in this direction was bound to continue, and this increased the importance of improving the measuring methods. The Scientific Advisory Committee of IAEA had expressed the view that it was important to attempt a synthesis of the experience in this field gained in different countries. The Vienna symposium was meant to serve that purpose

30

On the absolute measure of Beta activities  

International Nuclear Information System (INIS)

A new method for absolute beta counting of solid samples is given. The mea surements is made with an inside Geiger-Muller tube of new construction. The backscattering correction when using an infinite thick mounting is discussed and results for different materials given. (Author)

31

Absolute measurement of neutron cross sections. Progress report  

International Nuclear Information System (INIS)

The procedures and status of the absolute measurement of the neutron capture cross sections for 115In and 232Th are described. Work on the 239Pu fission fragment anisotropy and absolute measurement of the fast neutron fission cross section for 233U are briefly described. Progress in establishing the 14 MeV neutron measurements at the facility are discussed

32

Measurement of the absolute luminosity with the ALEPH detector  

Energy Technology Data Exchange (ETDEWEB)

We report on the absolute luminosity measurement performed with the ALEPH detector at LEP. The systematic errors of the measurements in 1990 are estimated to be 0.6% (experimental) and 0.3% (theoretical). (orig.).

Decamp, D.; Deschizeaux, B.; Goy, C.; Lees, J.P.; Minard, M.N. (CNRS, 74 - Annecy-le-Vieux (France). Lab. de Physique des Particules); Alemany, R.; Crespo, J.M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Mir, Ll.M.; Pacheco, A. (Universidad Autonoma de Barcelona (Spain). Lab. de Fisica de Altas Energias); Catanesi, M.G.; Creanza, D.; De Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G. (INFN, Bari (Italy) Bari Univ. (Italy). Dipt. di Fisica); Gao, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Lou, J.; Qiao, C.; Ruan, T.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W. (Academia Sinica, Beijing, BJ (China). Inst. of High-Energy Physics); Atwood, W.B.; Bauerdick, L.A.T.; Bird, F.; Blucher, E.; Bonvicini, G.; Bossi, F.; Boudreau, J.; Brown, D.; Burnett, T.H.; Drevermann, H.; Forty, R.W.; Grab, C.; Hagelberg, R.; Haywood,; ALEPH Collaboration

1992-02-01

33

Detection of Absolute Motion through Measurement of Synchronization Offsets  

Directory of Open Access Journals (Sweden)

Full Text Available An absolute reference frame may be defined as the one which is stationary with respect to the center of mass of the Universe and in which speed of propagation of light is an isotropic constant. Any motion with respect to this frame may be referred as absolute motion. In this paper we examine the Sagnac effect of absolute motion in the context of clock synchronization through GPS satellites in common view mode. The e-synchronization of two clocks A and B amounts to introduction of time offsets such that the time taken by a light pulse to propagate between A and B will be measured to be the same in both directions. Synchronization of two clocks through a GPS satellite in common view mode is effectively equivalent to e-synchronization of these clocks and introduces an absolute synchronization mismatch proportional to the absolute velocity and length of the baseline. Measurement of this synchronization offset between the GPS synchronized clocks at the ends of a long baseline will enable the practical detection of absolute motion of earth. Here we propose a simple experiment for detection of absolute motion through measurement of absolute synchronization offsets between two timing laboratories maintaining UTC time.

Gurcharn Singh Sandhu

2012-10-01

34

Measurement of Absolute Solar Infrared Radiation Through the Atmosphere  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The University of Denver's Absolute Solar Transmittance Interferometer (ASTI) has been developed and employed to radiometrically measure the infrared solar radiance and irradiance at the Earth's surface for several ground-level altitudes ranging from 300 to over 14,000 feet. ASTI also has a major research role in making absolutely calibrated IR measurements of on-axis and off-axis transmittance and scattering properties of numerous cloud types. These measurements and results will provide radi...

Dybdahl, Arthur W.

1996-01-01

35

Neutronic measurements of radioactive waste  

International Nuclear Information System (INIS)

This document presents the general matters involved in the radioactive waste management and the different non destructive assays of radioactivity. The neutronic measurements used in the characterization of waste drums containing emitters are described with more details, especially the active neutronic interrogation assays with prompt or delayed neutron detection: physical principle, signal processing and evaluation of the detection limit. (author)

36

Simple method for absolute activity measurement of 60Co source  

International Nuclear Information System (INIS)

The activity of 60Co source was measured using the full absorption, sum and random coincidence (pile-up) peaks and the total spectrum area. It is shown that if the true and random coincidences in the single detector are treated correctly, no additional data are needed for absolute source strength measurement. With the source on the detector end-cap (when the angular correlation effects are negligible), this simple method yields absolute activity values deviating from the reference activity by about 1%.

37

Absolute quantum yield measurement of powder samples.  

Science.gov (United States)

Measurement of fluorescence quantum yield has become an important tool in the search for new solutions in the development, evaluation, quality control and research of illumination, AV equipment, organic EL material, films, filters and fluorescent probes for bio-industry. Quantum yield is calculated as the ratio of the number of photons absorbed, to the number of photons emitted by a material. The higher the quantum yield, the better the efficiency of the fluorescent material. For the measurements featured in this video, we will use the Hitachi F-7000 fluorescence spectrophotometer equipped with the Quantum Yield measuring accessory and Report Generator program. All the information provided applies to this system. Measurement of quantum yield in powder samples is performed following these steps: 1. Generation of instrument correction factors for the excitation and emission monochromators. This is an important requirement for the correct measurement of quantum yield. It has been performed in advance for the full measurement range of the instrument and will not be shown in this video due to time limitations. 2. Measurement of integrating sphere correction factors. The purpose of this step is to take into consideration reflectivity characteristics of the integrating sphere used for the measurements. 3. Reference and Sample measurement using direct excitation and indirect excitation. 4. Quantum Yield calculation using Direct and Indirect excitation. Direct excitation is when the sample is facing directly the excitation beam, which would be the normal measurement setup. However, because we use an integrating sphere, a portion of the emitted photons resulting from the sample fluorescence are reflected by the integrating sphere and will re-excite the sample, so we need to take into consideration indirect excitation. This is accomplished by measuring the sample placed in the port facing the emission monochromator, calculating indirect quantum yield and correcting the direct quantum yield calculation. 5. Corrected quantum yield calculation. 6. Chromaticity coordinates calculation using Report Generator program. The Hitachi F-7000 Quantum Yield Measurement System offer advantages for this application, as follows: High sensitivity (S/N ratio 800 or better RMS). Signal is the Raman band of water measured under the following conditions: Ex wavelength 350 nm, band pass Ex and Em 5 nm, response 2 sec), noise is measured at the maximum of the Raman peak. High sensitivity allows measurement of samples even with low quantum yield. Using this system we have measured quantum yields as low as 0.1 for a sample of salicylic acid and as high as 0.8 for a sample of magnesium tungstate. Highly accurate measurement with a dynamic range of 6 orders of magnitude allows for measurements of both sharp scattering peaks with high intensity, as well as broad fluorescence peaks of low intensity under the same conditions. High measuring throughput and reduced light exposure to the sample, due to a high scanning speed of up to 60,000 nm/minute and automatic shutter function. Measurement of quantum yield over a wide wavelength range from 240 to 800 nm. Accurate quantum yield measurements are the result of collecting instrument spectral response and integrating sphere correction factors before measuring the sample. Large selection of calculated parameters provided by dedicated and easy to use software. During this video we will measure sodium salicylate in powder form which is known to have a quantum yield value of 0.4 to 0.5. PMID:22617474

Moreno, Luis A

2012-01-01

38

The fake of reliability measures as absolutes  

International Nuclear Information System (INIS)

It is claimed that any reliability measure defined in connection with a limit state theory of a high reliability technological system is a purely formal comparative measure of safety. It only makes sense to make comparisons wihtin classes of ''similar'' technological systems which are all accessible to the same theory. Interpretation of calculated formal failure probabilities as predictions of real failure rates are generally not justified. (orig.)

39

Absolute density measurements in the middle atmosphere  

Directory of Open Access Journals (Sweden)

Full Text Available In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values. Here, we present the results of both Monte Carlo simulations and wind tunnel measurements to quantify this aerodynamical effect. The comparison of the resulting ‘ram-factor’ profiles with empirically determined density ratios of ionization gauge measurements and falling sphere measurements provides excellent agreement. This demonstrates both the need, but also the possibility, to correct aerodynamical influences on measurements from sounding rockets. We have determined a total of 20 density profiles of the mesosphere-lower-thermosphere (MLT region. Grouping these profiles according to season, a listing of mean density profiles is included in the paper. A comparison with density profiles taken from the reference atmospheres CIRA86 and MSIS90 results in differences of up to 40%. This reflects that current reference atmospheres are a significant potential error source for the determination of mixing ratios of, for example, trace gas constituents in the MLT region.

Key words. Middle atmosphere (composition and chemistry; pressure, density, and temperature; instruments and techniques

M. Rapp

40

Measurements of Absolute Abundances in Solar Flares  

CERN Document Server

We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO). EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias ($f$). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is $...

Warren, Harry P

2013-01-01

 
 
 
 
41

Measurements of Absolute Abundances in Solar Flares  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO). EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the p...

Warren, Harry P.

2013-01-01

42

Absolute density measurements in the middle atmosphere  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the last ten years a total of 25 sounding rockets employing ionization gauges have been launched at high latitudes ( ~ 70° N) to measure total atmospheric density and its small scale fluctuations in an altitude range between 70 and 110 km. While the determination of small scale fluctuations is unambiguous, the total density analysis has been complicated in the past by aerodynamical disturbances leading to densities inside the sensor which are enhanced compared to atmospheric values...

Rapp, M.; Gumbel, J.; -j Lu?bken, F.

2001-01-01

43

Absolute Abundance Measurements in Solar Flares  

Science.gov (United States)

We present measurements of elemental abundances in solar flares with EVE/SDO and EIS/Hinode. EVE observes both high temperature Fe emission lines Fe XV-XXIV and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (F). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is F=1.17+-0.22. Furthermore, we have compared the EVE measurements with corresponding flare observations of intermediate temperature S, Ar, Ca, and Fe emission lines taken with EIS. Our initial calculations also indicate a photospheric composition for these observations. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation in the non-flaring corona occurs.

Warren, Harry

2014-06-01

44

Absolute Neutron Emission Measurement in Burning Plasma Experiments  

International Nuclear Information System (INIS)

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D-T or D-T operations. Here measurement techniques of time-resolved and time-integrated absolute neutron emission on the present tokamaks and ITER are reviewed. In the present tokamaks, fission chamber installed outside the vacuum vessel are very popular in the absolute neutron emission rate measurement. As well as conventional neutron monitors installed outside the vacuum vessel, in-vessel neutron monitors using micro fission chamber are proposed for the absolute neutron emission rate measurement in ITER. The neutron activation system provides time-integrated measurements of the total neutron yield with high accuracy by using well known neutron reaction cross sections, which is useful to maintain a robust measure of fusion energy production with stability and wide dynamic range. The calibration of the relation between the neutron emission rate in the whole plasma and the output of neutron monitor is the most important issue in the absolute neutron emission rate measurements. The calibration of the neutron detectors has been performed by moving a neutron source such as a 252Cf neutron or a small accelerator-based neutron generator. For the calibration in ITER, the neutron generator with neutron emission rate of 1011 s-1 or stronger is required to obtain high accuracy is required to obtain high accuracy

45

Absolute Earth Scale from SLR Measurements  

Science.gov (United States)

Since the LAGEOS I satellite was launched in 1976, the systematic instrument error of the best satellite laser ranging observatories has been steadily reduced. Advances in overall system accuracy, in conjunction with improved satellite, Earth, orbit perturbation and relativity modeling, now allows us to determine the value of the geocentric gravitational coefficient (GM) to less than a part per billion (ppb). This precision has been confirmed by observations of the LAGEOS II satellite, and is supported by results from Starlette, albeit at a lower level of precision. When we consider observations from other geodetic satellites orbiting at a variety of altitudes and carrying somewhat more complex retro-reflector arrays, we obtain consistent measures of scale, which however must be based upon empirically determined, satellite-dependent detector characteristics. The estimates of GM from SLR analysis fall comfortably within the ten ppb uncertainty of that determined from the most accurate alternative from lunar laser ranging observations. The adoption of a value of GM differing by a ppb would result in a difference of a few millimeters in the height definition of a near-Earth satellite. The precision of the estimate of GM from satellite laser ranging has improved by an order of magnitude in each of the last two decades, and we will discuss projected advances which will result in further refinements of this measure of Earth scale.

Dunn, P.; Torrence, M.; Kolenkiewicz, R.; Smith, D.

2002-05-01

46

Absolute measurements with a 4 ?-counter  

International Nuclear Information System (INIS)

Measurements on standardized p-emitters have been made in a 4 it proportional flow-counter. The counter efficiency is found to be near 100 %. Absorption curves have been determined with plastic foils and aluminium. A comparison is made between the self-absorption arising in different methods of source preparation which include precipitates and the use of wetting agents The most reliable results have been obtained with sources on aluminium foils, where the foil absorption is calculated from the absorption curves and the self-absorption is supposed to be negligible for isotopes with end point energy above 0.5 MeV. The ?-emitters studied have energies ranging from 1.71 MeV (32P) to 0.167 MeV (35S). Most of them have been obtained from National Physical Laboratory and Atomic Energy Research Establishment, Harwell, England. The agreement between their calibration and our measurements is very good except in the case of Co 60

47

Low-level Radioactivity Measurements  

International Nuclear Information System (INIS)

The objectives of the research performed in the area of low-level radioactivity measurements are (1) to maintain and develop techniques for the measurement of low-level environmental and biological samples, (2) to measure these samples by means of low-background counters (liquid scintillators, proportional counters, ZnS counters, alpha spectrometry), (3) to support and advice the nuclear and non-nuclear industry in matters concerning radioactive contamination and/or low-level radioactivity measurements; (4) to maintain the quality assurance system according to the EN45001/ISO17025 standard; and (5) to assess the internal dose from occupational intakes of radionuclides of workers of the nuclear industry. Progress and achievements in these areas in 2000 are reported

48

Laser-diode FMCW technique applied to absolute distance measurement  

Science.gov (United States)

A new method for measuring absolute distance is described which is based on the frequency modulated continuous wave (FMCV technique. The preliminary experiment results show that the accuracy can reach 0. 3mx at a distance of 7 meters and the measuring range can exceed 10 meters by using an external cavity laser diode

Cao, Mang; Li, Dacheng; Wu, Yongjun

1993-09-01

49

A simplified method of absolute measurement for liquid scintillation counter  

International Nuclear Information System (INIS)

A absolute measurement for simplified determining the activities of LS. sample is described. The total uncertainty of 2.0% and confidence level of 99.7% are given by the method, and as a example, three samples of 14C (n-hexadecane) are measured

50

Absolute branching fraction measurements of exclusive D+ semileptonic decays.  

Science.gov (United States)

Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e+e- storage ring, we present improved measurements of the absolute branching fractions of D+decays to K0e+ve, pi0e+ve, K*0e+ve, and p0e+ve, and the first observation and absolute branching fraction measurement of D+ --> omega e+ve. We also report the most precise tests to date of isospin invariance in semileptonic D0 and D+ decays. PMID:16383892

Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Adams, G S; Chasse, M; Cravey, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Muramatsu, H; Park, C S; Park, W; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dambasuren, E; Dorjkhaidav, O; Li, J; Menaa, N; Mountain, R; Nandakumar, R; Randrianarivony, K; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Briere, R A; Chen, G P; Chen, J; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Berkelman, K; Cassel, D G; Crede, V; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Gibbons, L; Gittelman, B; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Meyer, T O; Onyisi, P U E; Patterson, J R; Peterson, D; Phillips, E A; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Shepherd, M R; Stroiney, S; Sun, W M; Urner, D; Weaver, K M; Wilksen, T; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Patel, R; Potlia, V; Stoeck, H; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Gollin, G D; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; Williams, J; Wiss, J; Edwards, K W; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Li, S Z; Poling, R; Scott, A W; Smith, A; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ernst, J; Mahmood, A H; Severini, H; Asner, D M; Dytman, S A; Love, W; Mehrabyan, S; Mueller, J A; Savinov, V; Li, Z; Lopez, A; Mendez, H; Ramirez, J

2005-10-28

51

Radioactivity  

International Nuclear Information System (INIS)

This educative booklet give a general overview of radioactivity: history, structure of matter, radiations, radioactivity law, origin of radioactivity, radioactivity uses, radioprotection and measurement units. (J.S.)

52

Absolute continuity of hyperbolic invariant measures for endomorphisms  

International Nuclear Information System (INIS)

We prove that, for a C2 non-invertible but non-degenerate map f on a compact Riemannian manifold without boundary, a hyperbolic invariant measure ? is absolutely continuous with respect to the Lebesgue measure on the manifold if, under a condition on the Jacobian of the map, the measure satisfies two entropy formulae for positive exponents [13] and negative exponents [7], respectively. This implies that the entropy production e?(f) = 0 if and only if ? << Leb

53

Europe's Other Poverty Measures: Absolute Thresholds Underlying Social Assistance  

Science.gov (United States)

The first thing many learn about international poverty measurement is that European nations apply a "relative" poverty threshold and that they also do a better job of reducing poverty. Unlike the European model, the "absolute" U.S. poverty threshold does not increase in real value when the nation's standard of living rises, even though it is…

Bavier, Richard

2009-01-01

54

Statistical aspects in radioactivity measurements  

International Nuclear Information System (INIS)

This report contains a summary of basic concepts and formulae important for the treatment of errors and for calculating lower limits of detection in radioactivity measurements. Special attention has been paid to practical application and examples which are of interest for scientists working in this field. (orig./HP)

55

Environmental radioactivity intercomparison measurements  

International Nuclear Information System (INIS)

In the context of the North Cotentin radioecological group set up in 1997 by the Ministry of the Environment and the Ministry of the Secretariat d'Etat a la Sante, the Swiss Federal Office of Public health, a national organization of independent status with respect to nuclear energy, conducted a series of measurements in the north Cotentin in 1998. Some sites proposed by local association 'Angry mothers' were examined in particular. This association has now taken the initiative to organize a large scale international intercomparison, ' North Cotentin 2000', in the vicinity of local nuclear installations. Besides the scientific aspect of the intercomparison, a specific aim of this intercomparison consists in providing to the local population with a real opportunity for direct exchange with participating international teams. The primary concern of the workshop is the determination, by in situ gamma spectrometry, of both natural and artificial concentrations and resulting ambient dose rates at selected marine ( beach) and terrestrial sites. A particular aim of the workshop also is to test the capacity of mobile teams to produce reliable results in the field of low level measurements on trace of special radionuclides (I129, Sr90, H3, C14, and alpha emitters) from environmental samples, using both direct ( in situ) and differed ( laboratory methods). an overview of the results obtained will be prepared for the benefit of the public. (N.C.)

56

Beam energy absolute measurement using K-edge absorption spectrometers  

International Nuclear Information System (INIS)

A method is presented of absolute energy measurement with an accuracy of triangle ? ? 10-4?o by direct measurement of the bend angle in a high-precision magnetic dipole using two opposite-direction short (about 2 mm long) high-field-intensity magnets (bar ? dipole much-lt ?shortmag) installed at each end and two K-edge absorption spectrometers. Using these spectrometers and the hard x-ray synchrotron radiation created by the short magnets, a bend angle of 4.5 arc deg for the CEBAF energy bandwidth can be measured with an accuracy of a few units of 10-6 rad, and the main sources of systematic errors are the absolute measurement of the field integral and the determination of the centroid of the synchrotron beam at a wavelength equal to the K-edge absorption of the chosen substance

57

Absolute polarization measurement using a vector light shift.  

Science.gov (United States)

We have measured the vector light shift due to a cavity built-up optical lattice by using a variation of the Hanle effect with trapped Cs atoms, where the time-evolving population of all magnetic sublevels is measured in situ. The measurement is linearly sensitive to the electric field of the nonlinearly polarized light, which allows unprecedented sensitivity to absolute linear polarization quality, to the level of 10(-10) in fractional intensity. Our approach to measuring and improving linear polarization can be applied to electron electric dipole moment searches, optical lattice clocks, magnetometery, and quantum computing. PMID:24483655

Zhu, Kunyan; Solmeyer, Neal; Tang, Cheng; Weiss, David S

2013-12-13

58

Lens transmission measurement for an absolute radiation thermometer  

Energy Technology Data Exchange (ETDEWEB)

The lens transmission for the National Institute of Metrology of China absolute radiation thermometer is measured by a hybrid method. The results of the lens transmission measurements are 99.002% and 86.792% for filter radiometers with center wavelengths 633 nm and 900 nm, respectively. These results, after correcting for diffraction factors and the size-of-source effect when the lens is incorporated within the radiometer, can be used for measurement of thermodynamic temperature. The expanded uncertainty of the lens transmission measurement system has been evaluated. It is 1.3×10{sup ?3} at 633 nm and 900 nm, respectively.

Hao, X.; Yuan, Z.; Lu, X. [Division of Thermometry and Materials Evaluation, National Institute of Metrology, Beijing (China)

2013-09-11

59

Absolute Source Activity Measurement with a Single Detector  

International Nuclear Information System (INIS)

In the present paper the activity of 60Co source was measured using the full absorption, sum and random coincidences (pile up) peaks and the total spectrum area in the gamma spectra. By the exact treatment of the chance coincidence and pile-up events, surprisingly good results were obtained. With the source on the detector end-cap (when the angular correlation effects are negligible), this simple method yields absolute activity values deviating from the reference activity for about 1 percent.

60

Measuring absolute spectral radiance using an Erbium Doped Fibre Amplifier  

CERN Document Server

We describe a method to measure the spectral radiance of a source in an absolute way without the need of a reference. Here we give the necessary detail to allow for the device to be reproduced from standard fiber-optic components. The device is suited for fiber-optic applications at telecom wavelengths and calibration of powermeters and spectrometers at light levels from 1nW to 1uW.

Sanguinetti, Bruno; Monteiro, Fernando; Gisin, Nicolas; Zbinden, Hugo

2012-01-01

 
 
 
 
61

Absolute nuclear energy measurements using the ?-? coincidence method  

International Nuclear Information System (INIS)

I n this report a summary is first given of the principle of the ?-? calibration method, stress being laid on the corrections required. After a description of the equipment used, the choice of the experimental conditions required for various isotopes is discussed (22Na, 46Sc, 60Co, 88Y) and the agreement between these results and those obtained by other absolute measurement methods is considered. (authors)

62

Rapid and precise absolute distance measurements at long range  

Science.gov (United States)

The ability to determine absolute distance to an object is one of the most basic measurements of remote sensing. High-precision ranging has important applications in both large-scale manufacturing and in future tight formation-flying satellite missions, where rapid and precise measurements of absolute distance are critical for maintaining the relative pointing and position of the individual satellites. Using two coherent broadband fibre-laser frequency comb sources, we demonstrate a coherent laser ranging system that combines the advantages of time-of-flight and interferometric approaches to provide absolute distance measurements, simultaneously from multiple reflectors, and at low power. The pulse time-of-flight yields a precision of 3 µm with an ambiguity range of 1.5 m in 200 µs. Through the optical carrier phase, the precision is improved to better than 5 nm at 60 ms, and through the radio-frequency phase the ambiguity range is extended to 30 km, potentially providing 2 parts in 1013 ranging at long distances.

Coddington, I.; Swann, W. C.; Nenadovic, L.; Newbury, N. R.

2009-06-01

63

Precision Absolute Beam Current Measurement of Low Power Electron Beam  

Energy Technology Data Exchange (ETDEWEB)

Precise measurements of low power CW electron beam current for the Jefferson Lab Nuclear Physics program have been performed using a Tungsten calorimeter. This paper describes the rationale for the choice of the calorimeter technique, as well as the design and calibration of the device. The calorimeter is in use presently to provide a 1% absolute current measurement of CW electron beam with 50 to 500 nA of average beam current and 1-3 GeV beam energy. Results from these recent measurements will also be presented.

Ali, M. M.; Bevins, M. E.; Degtiarenko, P.; Freyberger, A.; Krafft, G. A.

2012-11-01

64

Absolute fluence measurement for a prototype neutron radiotherapy source.  

Science.gov (United States)

An inexpensive recoil-proton counter telescope has been designed for absolute fluence measurements of a gas-target neutron source for radiation therapy. The detector has an absolute efficiency of 1.1 times 10-minus 9 at 20 cm from an isotropic source and is useful for production rates of 10-9 minus 10-13 neutrons per second. The telescope consists of a thin hydrogenous irradiator foil and a surface-barrier detector to count recoil protons within a defined solid angle. The telescope provides n-gamma discrimination as well as discrimination against scattered neutrons. Initial tests of the counter telescope were performed using the DD reaction employed in development stages of the gas target. A clear separation of full-energy recoil protons from background and scattered neutron events was evident in the pulse-height spectra without the use of coincidence gating techniques. PMID:806776

Beach, J L; McCullough, E C

1975-01-01

65

Absolutely Continuous Invariant Measures of Piecewise Linear Lorenz Maps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Consider piecewise linear Lorenz maps on $[0, 1]$ of the following form \\[ f_{a,b,c}(x)= {ll} ax+1-ac & x \\in [0, c) b(x-c) & x \\in (c, 1].\\] We prove that $f_{a,b,c}$ admits an absolutely continuous invariant probability measure (acim) $\\mu$ with respect to the Lebesgue measure if and only if $f_{a,b,c}(0) \\le f_{a,b,c}(1)$, i.e. $ac+(1-c)b \\ge 1$. The acim is unique and ergodic unless $f_{a,b,c}$ is conjugate to a rational rotation. The equivalence between the acim and the...

Ding, Yi Ming; Fan, Ai Hua; Yu, Jing Hu

2010-01-01

66

Carbon clusters for absolute mass measurements at ISOLTRAP  

CERN Document Server

The cyclotron frequencies of singly charged carbon clusters C/sub n //sup +/ (n >or= 2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy delta m/m = 1.2.10/sup -8/ and the extent of the mass- dependent systematic shift ( delta m/m)/sub sys/ = 1.7(0.6).10/sup -10//u.(m - m/sub ref/) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the most abundant carbon isotope /sup 12/C are now possible at ISOLTRAP. (15 refs).

Blaum, K; Herfurth, F; Kellerbauer, A G; Kluge, H J; Kuckein, M; Sauvan, E; Scheidenberger, C; Schweikhard, L; 10.1140/epja/i2001-10262-4

2002-01-01

67

Carbon clusters for absolute mass measurements at ISOLTRAP  

International Nuclear Information System (INIS)

The cyclotron frequencies of singly charged carbon clusters Cn+ (n?2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy ?m/m=1.2.10-8 and the extent of the mass-dependent systematic shift (?m/m)sys=1.7(0.6).10-10/u.(m-m ref) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the most abundant carbon isotope 12C are now possible at ISOLTRAP. (orig.)

68

Measurement of absolute lung density by Compton-scatter densitometry  

International Nuclear Information System (INIS)

The non-invasive determination of absolute lung density would be of great importance if it could be used in the evaluation of patients with pulmonary edema. To obtain this measurement, we have developed a portable densitometer using CdTe room-temperature detectors, compact collimators made of tantalum tubes and a 153Gd source. System response in the density range of 0.1 to 1 g/cm3 is linear. Variations in the absorption paths of up to 8 cm of lucite do not produce significant changes on measured density values

69

Absolute measurement of important branching fractions of the Ds meson  

International Nuclear Information System (INIS)

Absolute measurement of branching fractions of purely leptonic decay, semi-leptonic decay and ??+ decay of the Ds meson at a c.m. energy of 4.03 GeV were completed from the BES experiment at the BEPC electron-positron collider. The method by using combined confidence level for pion and kaon separation, the Ds single and double tagging technology, and the maximum likelihood functions in the estimate of the Ds branching fractions are described in details. Discussion and comments on these physics results are made. Prospect for improved measurement of Ds physics in future is also given

70

Absolute measurements of ?-ray emission probabilities of 169Yb  

International Nuclear Information System (INIS)

A solution of 169Yb was absolutely standardized by the 4??(PC)-?[NaI(Tl)] coincidence counting method and the result has been used to obtain direct measurements of gamma-ray emission probabilities with a coaxial HPGe detector. Standard sources covering the energy range from 21 to 1408 keV were employed to obtain the efficiency-energy curve of the germanium detector. The efficiencies obtained by interpolating this curve were used to determine the emission probabilities of ?-rays following the decay of 169Yb. The half-life of 169Yb was also measured with a 4?-? ionization chamber

71

Absolute measurements of photon emission probabilities of 169Yb  

International Nuclear Information System (INIS)

A solution of 169Yb was absolutely standardized by the 4?(EC,X)-? coincidence counting method and the result was used to obtain direct measurements of gamma-ray emission probabilities with a coaxial HPGe detector. The empirical relation proposed by (Vano, F., Gonzalez, L., Gaeta R., Gonzalez, J.A., 1975. An empirical function which relates the slope of the Ge efficiency curves and the active volume Nucl. Instr. Meth. 123, 573) was tested using the gamma spectral response above 200 keV. The half-life of 169Yb was also measured with a 4?? ionization chamber

72

Interpretation of absolute measures of disease risk in comparative research.  

Science.gov (United States)

When comparing two groups, one receiving an experimental intervention and the other a placebo or nothing, researchers often wish to assess the disparity in risk of experiencing an event of interest, such as onset of disease. Relative risk, relative risk reduction, and odds ratio are often used to measure the association between potential benefit or harm and the intervention. However, these summary measures reflect relative disparities and are perhaps less useful in clinical practice than measures of absolute benefit or harm. We demonstrate that relative risk reduction is unaffected by the risk of an event in the control group and hence may either overestimate or underestimate the treatment effect. Absolute risk reduction accounts for the baseline control group event rate and is a more realistic quantification of treatment effect than relative measures. Number needed to treat (NNT) estimates the therapeutic effort needed to prevent one additional adverse event. NNT incorporates both relative risk reduction and the event rate without treatment. For a given relative risk reduction, we demonstrate the NNT will increase as the control event rate decreases. Thus, NNT has more-obvious implications for clinical decision making than risk estimates expressed in relative terms. PMID:17549653

Replogle, William H; Johnson, William D

2007-06-01

73

Effects of natural radioactivity on food radioactivity measurement  

International Nuclear Information System (INIS)

Since the accident of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Company, groups and individuals including local governments, food manufacturers, distribution circles, retail circles, and citizens are eager to measure the radioactivity of food, in order to confirm the safety of food from the concerns about radioactive contamination. The measurement of radioactivity of food is done by quantitatively determining gamma rays due to radioactive cesium that was incorporated into the biosphere cycle after having been released into the environment. As for the radioactivity measurement of food using gamma-ray spectrometry with a potassium iodide scintillation detector, which is very commonly used, this paper describes the handling method of obtained data, the principle of erroneous detection of radioactive cesium and iodine interrupted by natural radionuclides, and countermeasures for it. Major natural radioactivity sources are uranium series and thorium series. This paper explains gamma rays, which are characteristic in the decay process of uranium series and often affect the measurement of radioactive cesium in food and water. (O.A.)

74

Measurement of absolute emission rates of L X-rays  

International Nuclear Information System (INIS)

Many radionuclides of high atomic mass emit L x-rays from internal conversion as their only substantial photon emissions. It is hoped that by making careful measurements of the X and #betta#-ray intensities of a number of actinides, nuclides more suitable as standards in the calibration of low energy photon spectrometers than Am-241 might be found. Thorium 230, uranium 234, neptunium 237, plutonium 238, americium 241 and curium 244 were selected in order to determine the absolute emission rates of their L x-rays by alpha-particle gated L x-ray spectrometry

75

3D measurement of absolute radiation dose in grid therapy  

International Nuclear Information System (INIS)

Spatially fractionated radiotherapy through a grid is a concept which has a long history and was routinely used in orthovoltage radiation therapy in the middle of last century to minimize damage to the skin and subcutaneous tissue. With the advent of megavoltage radiotherapy and its skin sparing effects the use of grids in radiotherapy declined in the 1970s. However there has recently been a revival of the technique for use in palliative treatments with a single fraction of 10 to 20 Gy. In this work the absolute 3D dose distribution in a grid irradiation is measured for photons using a combination of film and gel dosimetry

76

High-precision absolute measurement of CEBAF beam mean energy  

International Nuclear Information System (INIS)

The absolute measurement of the beam mean energy with an accuracy of one part in 104 or higher is an important demand of the CEBAF Hall A physics program. This accuracy may reduce the uncertainty in the d(e, e'p)p cross section ??/? to 1%. The need for such an accurately calibrated beam is not particular to CEBAF; at other electron facilities uncertainty in the incident energy has proven to be among the dominant sources of systematic error. The following methods for solving the problem were considered at both CEBAF and the Yerevan Physics Institute during 1990--1991: Backscattering of a plane electromagnetic wave by the relativistic electron beam. Calculations show that the intensity of the backscattered radiation in a bandwidth of 10-4 near the maximum frequency is about 1 photon per second at 4 GeV and 0.3 mA. Magnetic spectrometers performing as three- and four-magnet chicanes with appropriate detector systems. Such a system was used at SLAC for absolute measurement of the SLC beams energy, where a maximum accuracy of 5 x 10-4 was achieved. Calculations show that a similar accuracy can be achieved for the CEBAF beam in both proposed systems. Measurement of the vertical distribution of synchrotron radiation. Calculations indicate that precision of about 2.5 x 10-5 is achievable for CEBAF

77

A technique for the absolute measurement of the W-value for X-rays in counting gases  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A technique was developed for the absolute measurement of the W-value (the mean energy for the production of an electron-ion pair) for low-energy X-rays in a wide range of gases at atmospheric pressures, with a standard uncertainty better than 1%. This technique is based on the absolute measurement of the primary ionization charge produced by X-ray photons from a constant intensity monoenergetic X-ray source, e.g. a long lifetime radioactive source. The ionization charge is calibrated by the ...

Vinagre, F. L. R.; Conde, C. A. N.

2000-01-01

78

Absolute distance measurement by two-point-diffraction interferometry  

International Nuclear Information System (INIS)

We present a point-diffraction interferometer that has been specially devised to perform absolute distance measurements in three dimensions. It is composed of two main parts: One is a target that moves in three dimensions, and the other is a stationary two-dimensional array of photodetectors. The target is made of point-diffraction sources that emit two spherical wave fronts, whose interference is monitored by the photodetectors. Application of a phase-shifting technique allows the phase values of the photodetectors to be precisely measured, which are then fitted to a geometric model of multilateration so as to determine the xyz location of the target by minimization of least-squares errors. Experimental results show that the proposed diffraction interferometer is capable of measuring the xyz coordinates of the target with a volumetric uncertainty of less than 1.0 ?m over a working volume of a 100-mm side

79

Quality Assurance In Radioactivity Measurements  

International Nuclear Information System (INIS)

The credibility of obtained results is ensured by the quality assurance and control. The main requisitions involved in the quality assurance of the laboratory according to the requirements of LVS EN ISO/IEC 17025:2005 are: 1) the use of calibrated equipment only; 2) the regular and long-time use of reference materials in the control of equipment; 3) the estimation of uncertainty sources and determination of uncertainties within the given interval of credibility; 4) the validation and verification. The very important requirement is regular participation in the interlaboratory intercomparison exercises that makes it possible to estimate and find possible error sources and carry out the corrective actions. The measurements of the radioactivity of Cs-137, Co-60, H-3, the natural radioactive nuclides as well as other radionuclides in different environmental (soil, precipitation, different types of water, needles, et al.) samples, and in various radioactive polluted objects are carried out in the Laboratory of Radiation physics. The quality assurance system was implemented in our laboratory in 2000. Since 1999 laboratory is regular participant in the interlaboratory intercomparison exercises, organized by the RISO National Laboratory (Denmark) and IAEA (Vienna). The paper shows the laboratory's system of quality assurance and its implementation. We have the internal quality audit program that takes into account the requirements of LVS EN ISO/IEC 17025: 2005, but the main attention is paid to the intercomparison of the results of analyses of laboratories, their evaluation and interpretation. Only credible and justified results can be the basis for further use in any field, thus making it possible to make legitimate decisions. (Authors)

80

Absolute solar flux measurement shortward of 575 A-circle  

International Nuclear Information System (INIS)

A rare-gas ionization chamber was used to obtain an accurate measurement of the absolute solar EUV flux in the 50- to 575-A-circle region. The instrument, operating in total and near-total absorption, was flown on a solar-pointing sounding rocket on August 16, 1983. For the day of the flight the solar activity indices were F/sub 10.7/ = 132.1 and R/sub I/ = 80, and the integrated solar irradiance at the earth, corrected for atmospheric absorption, was found to be 4.31 +- 0.31 x 1010 photons cm-2 s-1. Almost exactly a year earlier (August 10, 1982) the same instrument measured an integrated solar flux of 5.71 +- 0.42 x 1010 photons cm-2 s-1 during a time of enhanced solar activity (F/sub 10.7/ = 209.5 and R/sub I/ = 155)

 
 
 
 
81

Absolute 56Mn activity measurement by 4??-? coincidence counting technique  

International Nuclear Information System (INIS)

In order to determine the 56Mn ?-detection efficiency of a MnSO4 bath system, it is essential to do the absolute activity measurement of 56Mn solution. For the fabrication of 56Mn samples, a 13.718 mg of 56Mn metal flake with 99.99% purity was irradiated for 12 minutes at the thermal neutron field of about 1013 n/cm2s of flux density. The neutron activated 56Mn metal sample was dissolved in 50 ml of 0.1 N-HCl solution. The 56Mn samples were fabricated by using the dissolved stock solution and activity of each of them was measured by the 4??-? coincidence counting technique. The obtained result was 408.070 kBq/mg with total uncertainty of 0.366% at reference date, 0 h on October 15. 1987. (Author)

82

Deconstructing European Poverty Measures: What Relative and Absolute Scales Measure  

Science.gov (United States)

Forster and d'Ercole (2009) outline the dominant method of conceptualization and operationalization of European poverty measures that informed the EU in its development of the questionnaire for the European Union--Survey of Income and Living Conditions (EU-SILC). They do so in the context of their explanation of how the Organization for Economic…

Burkhauser, Richard V.

2009-01-01

83

Lunar eclipse photometry: absolute luminance measurements and modeling.  

Science.gov (United States)

The Moon's time-dependent luminance was determined during the 9 February 1990 and 3 March 2007 total lunar eclipses by using calibrated, industry standard photometers. After the results were corrected to unit air mass and to standard distances for both Moon and Sun, an absolute calibration was accomplished by using the Sun's known luminance and a pre-eclipse lunar albedo of approximately 13.5%. The measured minimum level of brightness in the total phase of both eclipses was relatively high, namely -3.32 m(vis) and -1.7 m(vis), which hints at the absence of pronounced stratospheric aerosol. The light curves were modeled in such a way as to let the Moon move through an artificial Earth shadow composed of a multitude of disk and ring zones, containing a relative luminance data set from an atmospheric radiative transfer calculation. PMID:19037352

Hernitschek, Nina; Schmidt, Elmar; Vollmer, Michael

2008-12-01

84

Absolute cross-section measurements of inner-shell ionization  

International Nuclear Information System (INIS)

Cross section ratios for K- and L-shell ionization of thin silver and gold targets by positron and electron impact have been determined at projectile energies of 30-70 keV. The experimental results are confirmed by calculations in plane wave Born approximation (PWBA) which include an electron exchange term and account for the deceleration or acceleration of the incident projectile in the nuclear field of the target atom. We report first absolute cross sections for K- and L-shell ionization of silver and gold targets by lepton impact in the threshold region. We have measured the corresponding cross sections for electron (e-) impact with an electron gun and the same experimental set-up. (orig.)

85

Absolute luminosity measurement at LHCb with beam-gas imaging  

International Nuclear Information System (INIS)

A novel technique to measure the absolute luminosity at the Large Hadron Collider (LHC) using beam-gas interactions has been successfully used in the LHCb experiment. The Beam-Gas Imaging method (BGI) has the potential to surpass the accuracy of the commonly used ''van der Meer scan'' method (VDM) but has been limited by the low statistic so far. A new device has been installed in the LHCb experiment to increase the pressure around the interaction point by mean of gas injection during dedicated fills. This talk presents the principles of the gas injection and the improvements expected with the increased pressure. Furthermore the gas injection will now help to evaluate the so-called ghost charges and also to better quantify the intensities per bunch. Those uncertainties are becoming the dominating factor because the uncertainty on the total beam current have been reduced.

86

A quantitative PCR method for measuring absolute telomere length  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract We describe a simple and reproducible method to measure absolute telomere length (aTL using quantitative real-time polymerase chain reaction (qPCR. This method is based on the Cawthon method for relative measurement of telomere length (TL but modified by introducing an oligomer standard to measure aTL. The method describes the oligomer standards, the generation of the standard curve and the calculations required to calculate aTL from the qPCR data. The necessary controls and performance characteristics of the assay are described in detail and compared relative to other methods for measuring TL. Typical results for this assay for a variety of human tissue samples are provided as well as a troubleshooting schedule. This method allows high throughput measurement of aTL using small amounts of DNA making it amenable for molecular epidemiological studies. Compared to the traditional relative TL qPCR assays, the aTL method described in this protocol enables a more direct comparison of results between experiments within and between laboratories.

Fenech Michael

2011-01-01

87

Measured and modelled absolute gravity changes in Greenland  

DEFF Research Database (Denmark)

In glaciated areas, the Earth is responding to the ongoing changes of the ice sheets, a response knownas glacial isostatic adjustment (GIA). GIA can be investigated through observations of gravity change.For the ongoing assessment of the ice sheets mass balance, where satellite data are used, the study ofGIA is important since it acts as an error source. GIA consists of three signals as seen by a gravimeter onthe surface of the Earth. These signals are investigated in this study. The ICE-5G ice history and recentlydeveloped ice models of present day changes are used to model the gravity change in Greenland. Theresult is compared with the initial measurements of absolute gravity (AG) change at selected GreenlandNetwork (GNET) sites.We find that observations are highly influenced by the direct attraction from the ice and ocean. Thisis especially evident in the measurements conducted at the GNET station near the Helheim Glacier.The effect of the direct attraction diminishes at sites that are more than one degreefrom the source.Here, the dominant signal is the effect of the elastic signal from present day ice mass changes. We findagreement between the measured and modelled gravity changes at all but one site. This agreement onlyholds when the direct attraction is considered. For one site, there is no agreement, indicating that someimprovements to the modelling results or the processing of the gravity data are needed. In addition, moreAG measurements are needed to strengthen the time series of gravity change.

Nielsen, Jens Emil; Forsberg, René

2014-01-01

88

Measurement of radioactivity in water samples  

International Nuclear Information System (INIS)

Public concern about the levels of radioactivity release to the environment whether authorised discharges or resulting from nuclear accident, has increased in recent years. Consequently there is increasing pressure for reliable data on the distribution of radioactivity and the extent of its intrusion into food chains and water supplies. As a result a number of laboratories not experienced in radioactivity measurements have acquired nucleonic counting equipment. These notes explore the underlying basics and indicate sources of essential data and information which are required for a better understanding of radioactivity measurements. Particular attention is directed to the screening tests which are usually designated ''gross'' alpha and ''gross'' beta activity measurement. (author)

89

Absolute measurements of the thermal neutron flux by the foil activation method using the 4??-? coincidence technique  

International Nuclear Information System (INIS)

An analysis of the correction factors required for the ?-? coincidence method is presented together with a listing of the various formulae involved in the determination of radioactive sources. The detection system including the activation detectores are described and the results are shown for the absolute measurements of thermal neutron flux carried out in the core of the Argonaut Reactor, at Instituto de Engenharia Nuclear (IEN), Brazil. (Author)

90

Absolute activity measurement of radon gas at IRA-METAS  

International Nuclear Information System (INIS)

This paper describes the system of the Swiss national metrological institute (IRA-METAS) for the absolute standardisation of radon gas. This method relies on condensing radon under vacuum conditions within a specified cold area using a cryogenerator, and detecting its alpha particles with an ion-implanted silicon detector, through a very accurately defined solid angle. The accuracy of this defined solid angle standardisation technique was corroborated by another primary measurement method involving 4?? NaI(Tl) integral counting and Monte Carlo efficiency calculations. The 222Rn standard submitted by IRA-METAS to the Systeme International de Reference (SIR) at the Bureau International des Poids et Mesures (BIPM) has also been found to be consistent with an analogous standard submitted by the German national metrological institute (PTB). IRA-METAS is able to deliver radon standards, with activities ranging from a few kBq to 350 kBq, in NIST-Type ampoules, and glass or steel containers usable for calibrating radon-measuring instruments

91

Absolute Measurement Of EUV Radiation From An Undulator  

Science.gov (United States)

Driven by the needs for microlithography, powerful sources for extreme ultraviolet (EUV) radiation at wavelengths around 13 nm are currently under development. For absolute photon flux measurements of highly intense and extremely pulsed radiation in the VUV and EUV spectral range, a detector system based on the photoionization of rare gases has been developed. Due to its extended dynamic range, the device can be calibrated with spectrally dispersed synchrotron radiation at low photon intensities, but applied for high power sources like recently at the VUV-FEL of the TESLA test facility at DESY. The detector is free of degradation and almost transparent, and therefore suitable for intensity monitoring. Here we describe the application of the detector for flux measurements at a beamline for undispersed, deflected undulator radiation in the PTB Radiometry Laboratory at the electron storage ring BESSY II. This beamline is used for development and lifetime testing of components for EUV lithography, where accurate determination of the incident radiant power is needed, e.g. for exposure dose control. Taking advantage of the characteristic photoionization cross sections for different rare gases in the soft x-ray wavelength range, contributions of higher undulator harmonics could be determined and suppressed for EUV (13 nm) power measurements. While in normal operation the BESSY II radiation can be seen as quasi-continuous (500 MHz repetition rate), in single-bunch operation mode (1.25 MHz) measurements of the power for single EUV pulses have been performed. This demonstrates the capability of the gas detector for a broad range of applications with pulsed EUV sources.

Gottwald, A.; Klein, R.; Müller, R.; Richter, M.; Sorokin, A. A.; Ulm, G.

2004-05-01

92

Embedded north-seeker for automatic absolute magnetic DI measurements  

Science.gov (United States)

In magnetic observatory Earth magnetic field is recorded with a resolution of 0.1nT for 1min sampling (new standards impose 1pT for 1s sampling). The method universally adopted for measuring it is a combination of three instruments. Vectorial magnetometer (variometer) records variations of the three components around a reference value or a baseline. A proton or an overhauser magnetometer is an absolute instrument able to measure the modulus of the field and used to determine the F component baseline of the variometer. The declination and inclination baselines require a manual procedure to be computed. An operator manipulates a non-magnetic theodolite (also called a DIFlux) to measure the D and I angles in different configurations with a resolution of a few arcsec. The AutoDIF is a non-magnetic automatic DIFlux using the same protocol as the manual procedure. The declination defined according to the true north is determined by means of a target pointing system. Even if the technique is fast and accurate, it becomes problematic in case of unmanned deployment. In particular the area between the target and the DIFlux is out of control. Snow storm, fog, vegetation or condensation on windows are examples of perturbation preventing for finding the target. It is obvious in case of (future) seafloor observatories. A FOG based north-seeker has been implemented and mounted on the AutoDIF. The first results using a low cost gyro don't meet the Intermagnet specifications yet but are however hopeful. A 0.1° standard deviation has been reached and statistically reduced to 0.01° after less than two days in laboratory. The magnetic disturbance of the sensor is taken into account and compensated by the measurement protocol.

Gonsette, Alexandre; Rasson, Jean

2014-05-01

93

ATLAS ALFA-measuring absolute luminosity with scintillating fibres  

International Nuclear Information System (INIS)

ALFA is a high-precision scintillating fibre tracking detector under construction for the absolute determination of the LHC luminosity at the ATLAS interaction point. This detector, mounted in so-called Roman Pots, will track protons elastically scattered under ?rad angles at IP1.In total there are four pairs of vertically arranged detector modules which approach the LHC beam axis to mm distance. Each detector module consists of ten layers of two times 64 scintillating fibres each (U and V planes). The fibres are coupled to 64 channels Multi-Anodes PhotoMultipliers Tubes read out by compact front-end electronics. Each detector module is complemented by so-called overlap detectors: Three layers of two times 30 scintillating fibres which will be used to measure the relative positioning of two vertically arranged main detectors. The total number of channels is about 15000. Conventional plastic scintillator tiles are mounted in front of the fibre detectors and will serve as trigger counter. The extremely restricted space inside the pots makes the coupling to the read out devices very challenging. Several technologies have been tested in a beam at DESY and a cosmic-ray setup at CERN. A possible upgrade of the photo detection could consist in the replacement of the PMT by Geiger-mode avalanche photodiodes. Preliminary tests are being performed comparing the performance of these devices with the ones of the PMTs.

94

Method of improve detection efficiency for liquid scintillation absolute measurement  

International Nuclear Information System (INIS)

Introduce practical method to improve the detection efficiency of 3H, 14C sample, as used for metrology technique research, graduation solution of 3H, 14C by National Primary Standard of 4??(LS) radioactivity. (authors)

95

Measurements of natural radioactivity in phosphate fertilizers  

International Nuclear Information System (INIS)

The natural radioactivity, mainly due to radium (226Ra), in phosphate fertilizers used in north-western Greece has been measured by ?-spectroscopy. Also radioactivity measurements were performed in soil samples and were compared to samples from undisturbed soils. 226Ra belongs to the 238U chain and is the precursor of radon gas (222Rn). The radon concentrations in warehouses, where large quantities of fertilizers are kept, were measured with CR-39 SSNTDs. The radium concentrations in the fertilizers ranged from 0 to 4584 Bq kg-1 and the radon concentrations in warehouses were measured 540-3320 Bq m-3. The results are discussed from the radiation protection point of view

96

Accurate absolute measurement of trapped Cs atoms in a MOT  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Una Trampa Magneto-Óptica (MOT) de Cs-133 se ha desarrollado en la División de Tiempo y Frecuencia del Centro Nacional de Metrología, CENAM, en Mexico. Esta MOT es parte de un patrón primario de frecuencia basado en átomos ultra fríos de Cs, llamado reloj CsF-1 que se encuentra en desarrollo en el C [...] ENAM. En esta MOT de Cs, se emplea la configuracion estándar (?+ - ?-) de 4 haces laser horizontales y 2 verticales de 1.9 cm de diametro con 5 mW de potencia cada uno. Se utiliza un láser DBR de 852 nm y 5 mW como láser maestro estabilizado por espectroscopia de saturación. El ancho de línea de emision del láser maestro es de 1 MHz. Para amplificar la luz del láser maestro, se emplea un laser esclavo de AlGaAs de 852 nm y 50 mW de potencia. Este láser esclavo es estabilizado por la técnica de inyección de luz. Se realiza un corrimiento de la luz al rojo de 12 MHz por un doble paso a través de dos Moduladores Acusto-Ópticos (AOMs). La parte óptica de la MOT del CENAM es muy robusta contra la vibracion mecánica, el ruido acústico y los cambios de temperatura en el laboratorio, debido a que ninguno de los diodos laser emplea una cavidad extendida para reducir el ancho de línea. En este trabajo se reportan los resultados de la caracterizacion de la MOT como una función de varios parámetros de operación tales como: intensidad y diámetro de los haces láser, corrimiento al rojo de la luz y el gradiente de campo magnético. También se reportan mediciones absolutas del número de átomos de Cs atrapados en la MOT. Se encontraron mas de 6 x 10(7) atomos de Cs atrapados, medidos con una incertidumbre que en ningún caso es mayor a 6.4%. Abstract in english A Cs-133 Magneto-Optical Trap (MOT) has been developed at the Time and Frequency Division of the Centro Nacional de Metrología, CENAM, in Mexico. This MOT is part of a primary frequency standard based on ultra-cold Cs atoms, called CsF-1 clock, under development at CENAM. In this Cs MOT, we use the [...] standard configuration (?+ - ?-) 4-horizontal 2-vertical laser beams 1.9 cm in diameter, with 5 mW each. We use a 852 nm, 5 mW, DBR laser as a master laser which is stabilized by saturation spectroscopy. Emission linewidth of the master laser is 1 MHz. In order to amplify the light of the master laser, a 50 mW, 852 nm AlGaAs laser is used as slave laser. This slave laser is stabilized by light injection technique. A 12 MHz red shift of the light is performed by two double passes through two Acusto-Optic Modulators (AOMs). The optical part of the CENAMs MOT is very robust against mechanical vibration, acoustic noise and temperature changes in our laboratory, because none of our diode lasers use an extended cavity to reduce the linewidth. In this paper, we report results of our MOT characterization as a function of several operation parameters such as the intensity of laser beams, the laser beam diameter, the red shift of light, and the gradient of the magnetic field. We also report accurate absolute measurement of the number of Cs atoms trapped in our Cs MOT. We found up to 6 x 10(7) Cs atoms trapped in our MOT measured with an uncertainty no greater than 6.4%.

M., Talavera O.; M., López R.; E., de Carlos L.; S., Jiménez S.

97

Accurate absolute measurement of trapped Cs atoms in a MOT  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Una Trampa Magneto-Óptica (MOT) de Cs-133 se ha desarrollado en la División de Tiempo y Frecuencia del Centro Nacional de Metrología, CENAM, en Mexico. Esta MOT es parte de un patrón primario de frecuencia basado en átomos ultra fríos de Cs, llamado reloj CsF-1 que se encuentra en desarrollo en el C [...] ENAM. En esta MOT de Cs, se emplea la configuracion estándar (?+ - ?-) de 4 haces laser horizontales y 2 verticales de 1.9 cm de diametro con 5 mW de potencia cada uno. Se utiliza un láser DBR de 852 nm y 5 mW como láser maestro estabilizado por espectroscopia de saturación. El ancho de línea de emision del láser maestro es de 1 MHz. Para amplificar la luz del láser maestro, se emplea un laser esclavo de AlGaAs de 852 nm y 50 mW de potencia. Este láser esclavo es estabilizado por la técnica de inyección de luz. Se realiza un corrimiento de la luz al rojo de 12 MHz por un doble paso a través de dos Moduladores Acusto-Ópticos (AOMs). La parte óptica de la MOT del CENAM es muy robusta contra la vibracion mecánica, el ruido acústico y los cambios de temperatura en el laboratorio, debido a que ninguno de los diodos laser emplea una cavidad extendida para reducir el ancho de línea. En este trabajo se reportan los resultados de la caracterizacion de la MOT como una función de varios parámetros de operación tales como: intensidad y diámetro de los haces láser, corrimiento al rojo de la luz y el gradiente de campo magnético. También se reportan mediciones absolutas del número de átomos de Cs atrapados en la MOT. Se encontraron mas de 6 x 10(7) atomos de Cs atrapados, medidos con una incertidumbre que en ningún caso es mayor a 6.4%. Abstract in english A Cs-133 Magneto-Optical Trap (MOT) has been developed at the Time and Frequency Division of the Centro Nacional de Metrología, CENAM, in Mexico. This MOT is part of a primary frequency standard based on ultra-cold Cs atoms, called CsF-1 clock, under development at CENAM. In this Cs MOT, we use the [...] standard configuration (?+ - ?-) 4-horizontal 2-vertical laser beams 1.9 cm in diameter, with 5 mW each. We use a 852 nm, 5 mW, DBR laser as a master laser which is stabilized by saturation spectroscopy. Emission linewidth of the master laser is 1 MHz. In order to amplify the light of the master laser, a 50 mW, 852 nm AlGaAs laser is used as slave laser. This slave laser is stabilized by light injection technique. A 12 MHz red shift of the light is performed by two double passes through two Acusto-Optic Modulators (AOMs). The optical part of the CENAMs MOT is very robust against mechanical vibration, acoustic noise and temperature changes in our laboratory, because none of our diode lasers use an extended cavity to reduce the linewidth. In this paper, we report results of our MOT characterization as a function of several operation parameters such as the intensity of laser beams, the laser beam diameter, the red shift of light, and the gradient of the magnetic field. We also report accurate absolute measurement of the number of Cs atoms trapped in our Cs MOT. We found up to 6 x 10(7) Cs atoms trapped in our MOT measured with an uncertainty no greater than 6.4%.

M., Talavera O.; M., López R.; E., de Carlos L.; S., Jiménez S.

2007-10-01

98

Measurement of environmental radioactivity. Ispra 1977  

International Nuclear Information System (INIS)

In this report there are briefly described the measurements of environmental radioactivity performed during 1977 by the site survey group of the Protection Division of the Euratom joint Research Centre - Ispra Establishement. Data are given on the concentrations of 90Sr, 137Cs and other radionuclides in precipitation, air, waters, herbage, milk and radioactive effluents. The environmental contamination is mainly world-wide fall out

99

Experimental and measurement issues in natural radioactivity  

Energy Technology Data Exchange (ETDEWEB)

The paper deals with some open experimental problems in the field of natural radioactivity. Its aim is to stimulate discussion on the type of research efforts needed in the field and to be planned for the future. The review, which makes no claims to completeness, analyses some issues in gamma spectrometry of natural radionuclides, and the measurement of natural radioactivity in non-nuclear industries and of {sup 222}Rn and {sup 220}Rn concentration in air. (author)

Risica, S.; Bochicchio, F.; Bolzan, C.; Grisanti, G.; Nuccetelli, C

2001-07-01

100

Experimental and measurement issues in natural radioactivity.  

Science.gov (United States)

The paper deals with some open experimental problems in the field of natural radioactivity. Its aim is to stimulate discussion on the type of research efforts needed in the field and to be planned for the future. The review, which makes no claims to completeness. analyses some issues in gamma spectrometry of natural radionuclides, and the measurement of natural radioactivity in non-nuclear industries and of 222Rn and 220Rn concentration in air. PMID:11878417

Risica, S; Bochicchio, F; Bolzan, C; Grisanti, G; Nuccetelli, C

2001-01-01

 
 
 
 
101

Experimental and measurement issues in natural radioactivity  

International Nuclear Information System (INIS)

The paper deals with some open experimental problems in the field of natural radioactivity. Its aim is to stimulate discussion on the type of research efforts needed in the field and to be planned for the future. The review, which makes no claims to completeness, analyses some issues in gamma spectrometry of natural radionuclides, and the measurement of natural radioactivity in non-nuclear industries and of 222Rn and 220Rn concentration in air. (author)

102

Single detector-based absolute velocity measurement using spectral domain Doppler optical coherence tomography  

Science.gov (United States)

We propose an approach for absolute velocity measurement where the use of a beam displacer provides two orthogonal linearly polarized beams to probe the sample simultaneously at two different incidence angles. The approach helps remove the cross talk image and facilitates single detector-based Fourier domain Doppler velocity measurement. The system has been characterized by quantifying absolute flow velocity in a flow phantom.

Kumar, S.; Verma, Y.; Sharma, P.; Shrimali, R.; Gupta, P. K.

2014-10-01

103

Gravity measurements with a portable absolute gravimeter A10 in Syowa Station and Langhovde, East Antarctica  

Science.gov (United States)

Absolute gravity values were measured with a portable absolute gravimeter A10 in East Antarctica, for the first time by the Japanese Antarctic Research Expedition. This study aims to investigate regional spatiotemporal variations of ice mass distributions and associated crustal deformations around Syowa Station by means of repeated absolute gravity measurements, and we obtained the first absolute gravity value in Southern Langhovde on the Antarctic Continent. The average absolute gravity value at the newly installed benchmark AGS01 in Langhovde (obtained on 3 February 2012) was 982535584.2 ± 0.7 ?gal (1 [?gal] = 1 × 10-8 [m/s2]), which was in agreement with the gravity values obtained by the past relative gravity measurements within 1 mgal. In addition, the average absolute gravity value obtained at AGSaux in Syowa Station was consistent with both previous absolute gravity values and those obtained by simultaneous measurements using an FG5 gravimeter, owing to adequate data corrections associated with tidal effects and time variations in atomic clock frequencies. In order to detect the gravity changes associated with the ice mass changes and other tectonic phenomena, we plan to conduct absolute gravity measurements at AGS01 again and at other campaign sites around Syowa Station as well in the near future, with careful attention paid to the impacts of severe environmental conditions in Antarctica on gravity data collection.

Kazama, Takahito; Hayakawa, Hideaki; Higashi, Toshihiro; Ohsono, Shingo; Iwanami, Shunsuke; Hanyu, Tomoko; Ohta, Harumi; Doi, Koichiro; Aoyama, Yuichi; Fukuda, Yoichi; Nishijima, Jun; Shibuya, Kazuo

2013-09-01

104

Absolutmaetning av Fotoutbytet hos Metall-Halvledar-Detektorer (Absolute Photoyield Measurements on Metal-Semiconductor Detectors).  

Science.gov (United States)

A method for measuring the absolute photoyield on Metal-Semiconductor Detectors has been developed. Measurements were performed on Metal-Semiconductor structures with palladium, palladium silicide, platina and gold as metal layers on p-type silicon. The p...

B. Larsson

1986-01-01

105

NKS 1999 intercomparison of measurements of radioactivity  

International Nuclear Information System (INIS)

34 laboratories have returned radioactivity measurements on six different environmental samples. The samples were analysed for their content of gamma emitters, Sr-90, transuranics and Tc-99. The samples materials are described and the results presented. Some scatter was observed in measurements of Cs-137 in low-level samples such as dry milk, meat and hay. The scatter was less pronounced for sediments and seaweed material that had higher levels of radioactivity. In general, the most of the results were consistent with a few laboratories reporting outlying values. An exception was seawater where no clear agreement could be found for the activity of Cs-137. (au)

106

Environmental radioactivity: measurements and their meaning  

International Nuclear Information System (INIS)

Radioactivity in the environment includes naturally occurring as well as man-made radionuclides. Meaningful estimates of their hazard to health require much care in obtaining representative environmental samples, appropriate sample preparation as well as proper calibration of the measuring system. Any harm from the low absorbed doses of ionizing radiation typically received from environmental radioactivity would only occur after a latent period of several years. Of these, cancer induction is considered to be the most important. Risk factors have been derived by a number of internationally recognized organizations, but there are difficulties in extrapolating from observations at a high dose and dose rate and for the lifetime of exposed populations. Examples of measurement of 222Ra, 90Sr, 125I, 226Ra, 129I and 137Cs in the environment are given. Harmful effects from environmental radioactivity have mostly been indistinguishable above natural incidence. (author)

107

Radioactivity measurements on live Bewick's Swans  

International Nuclear Information System (INIS)

Measurements made on 46 live swans at Slimbridge using portable high resolution hyperpure germanium gamma ray spectrometry equipment are described. Laboratory measurements are also reported on two swans which died of natural causes or of flying accidents. The implications of the measured radioactivity levels are discussed in relation to the suggestion that they might have been affected by the Chernobyl accident on their migration. (UK)

108

Environmental radioactivity measurement intercomparison exercise 1990  

International Nuclear Information System (INIS)

In a recent national intercomparison exercise, 49 laboratories involved in making environmental radioactivity measurements took part in the analysis of samples supplied by the National Physical Laboratory (NPL) in the United Kingdom. There were two sets of samples; one containing pure ?-emitters and one containing ?/?-emitters. Two thirds of the participants measured the ?/?-emitter sample only, the remainder measured both. The results are presented. (author)

109

A novel method for the absolute fluorescence yield measurement by AIRFLY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One of the goals of the AIRFLY (AIR FLuorescence Yield) experiment is to measure the absolute fluorescence yield induced by electrons in air to better than 10% precision. We introduce a new technique for measurement of the absolute fluorescence yield of the 337 nm line that has the advantage of reducing the systematic uncertainty due to the detector calibration. The principle is to compare the measured fluorescence yield to a well known process - the Cerenkov emission. Preli...

Airfly, Collaboration; Ave, M.

2008-01-01

110

Applications of computer in radioactivity measurement  

International Nuclear Information System (INIS)

The applications of computer on radioactivity measuring is described . A liquid scintillation nuclear activity metrology instrument includes three phototube coincidence detectors and IBM-PC computer. The triple-to-double coincidence ratio (TDCR) is used as the quenching index. According to extrapolating the efficiency curve to TDCR = 1, the activity value of the ? and ? emitters can be easily calculated

111

System for measuring radioactivity of labelled biopolymers  

International Nuclear Information System (INIS)

A system is described for measuring radioactivity of labelled biopolymers, comprising: a set of containers adapted for receiving aqueous solutions of biological samples containing biopolymers which are subsequently precipitated in said containers on particles of diatomite in the presence of a coprecipitator, then filtered, dissolved, and mixed with a scintillator; radioactivity measuring means including a detection chamber to which is fed the mixture produced in said set of containers; an electric drive for moving said set of containers in a stepwise manner; means for proportional feeding of said coprecipitator and a suspension of diatomite in an acid solution to said containers which contain the biological sample for forming an acid precipitation of biopolymers; means for the removal of precipitated samples from said containers; precipitated biopolymer filtering means for successively filtering the precipitate, suspending the precipitate, dissolving the biopolymers mixed with said scintillator for feeding of the mixture to said detection chamber; a system of pipelines interconnecting said above-recited means; and said means for measuring radioactivity of labelled biopolymers including, a measuring cell arranged in a detection chamber and communicating with said means for filtering precipitated biopolymers through one pipeline of said system of pipelines; a program unit electrically connected to said electric drive, said means for acid precipatation of biopolymers, said means for the removal of precipitated samples from said containers, said filtering means, and said radioactivity measuring device; said program unit adapted to periodically switch on and off the above-recited means and check the sequence of the radioactivity measuring operations; and a control unit for controlling the initiation of the system and for selecting programs

112

Nondestructive measurement of environmental radioactive strontium  

Science.gov (United States)

The Fukushima Daiichi nuclear power plant accident was triggered by the 2011 Great East Japan Earthquake. The main radioactivity concerns after the accident are I-131 (half-life: 8.0 days), Cs-134 (2.1 years), Cs-137 (30 years), Sr-89 (51 days), and Sr-90 (29 years). We are aiming to establish a new nondestructive measurement and detection technique that will enable us to realize a quantitative evaluation of strontium radioactivity without chemical separation processing. This technique is needed to detect radiation contained in foods, environmental water, and soil, to prevent us from undesired internal exposure to radiation.

Saiba, Shuntaro; Okamiya, Tomohiro; Tanaka, Saki; Tanuma, Ryosuke; Totsuka, Yumi; Murata, Jiro

2014-03-01

113

Nondestructive measurement of environmental radioactive strontium  

Directory of Open Access Journals (Sweden)

Full Text Available The Fukushima Daiichi nuclear power plant accident was triggered by the 2011 Great East Japan Earthquake. The main radioactivity concerns after the accident are I-131 (half-life: 8.0 days, Cs-134 (2.1 years, Cs-137 (30 years, Sr-89 (51 days, and Sr-90 (29 years. We are aiming to establish a new nondestructive measurement and detection technique that will enable us to realize a quantitative evaluation of strontium radioactivity without chemical separation processing. This technique is needed to detect radiation contained in foods, environmental water, and soil, to prevent us from undesired internal exposure to radiation.

Saiba Shuntaro

2014-03-01

114

Radioactivity measurements as tool for physics dissemination  

International Nuclear Information System (INIS)

In general people associate environmental radioactivity with the artificial radioactivity and knows very little about natural radioactivity. Thus there is a critical need to improve nuclear physics public education. From 2005 in Italy two programs were promoted from Ministry of Education and University and National Institute of Nuclear Physics (INFN) for scientific dissemination in the field of environmental radioactivity. High school students in many Italian regions were involved in particular in indoor radon measurements. With this program students acquired awareness about the risks of inhalation of radon and its progeny and at the same time contributed to carry out radon monitoring, participating to all the experimental phases, from detectors set-up to data analysis. In particular we report about the activities carried out at Catania University and INFN division regarding a survey in the eastern Sicily. The overall monitoring, spanned over a period of 5 years, was carried out using passive nuclear track detection technique, through CR-39 dosimeters. In total about 500 detectors were placed in dwellings and schools in 57 locations. The investigated area have shown medium-high indoor radon concentrations, higher than the Italian average (70 Bq/m3). From the evaluation of the participating teachers and students, this kind of activities represents a successful strategy to enhance dissemination of physics, in particular in radioactivity topics. (author)

115

Measurement of environmental radioactivity in Toki district  

International Nuclear Information System (INIS)

When the Institute of Plasma Physics, Nagoya University, expressed the hope to move into Toki district, the environmental problems accompanying the movement were discussed. The effect of the radioactivity leaking from the nuclear facility on human bodies must be far smaller than that of natural radiation, and for the purpose, the amount and fluctuation range of the natural radiation in the district must be known. The initial objectives of this cooperative research were to study on environmental radiation and to make a Geiger counter for the measurement. In 1981, a scintillation counter will be completed, and using a multi-channel pulse height analyzer, the nuclides which are the source of environmental radiation emission will be identified, and the tritium in natural water will be detected. Thus, the evaluation of environmental radiation can be carried out, and the situation before the movement of the research facility can be grasped. In this paper, the natural radioactivity in earth, atmosphere and water and cosmic ray, artificial radioactivity, and environmental radiation exposure dose are reported. Also, the manufacture of a GM counter measuring instrument and the measurements of cosmic ray background, typical earth samples and environmental radioactivity with the GM counter are reported. The related data are attached. (Kako, I.)

116

Environmental radioactivity - problems in activity measurements  

International Nuclear Information System (INIS)

Laboratory methods for the measurement of radioactivity in environmental samples are considered to be well developed and established. After the Chernobyl accident, however, it became evident that not everywhere was one prepared for quick in-situ activity measurements and that many measurement results were questionable. We show the difficulties occurring in activity measurements with simple instruments to be used directly in the environment. In addition, several problems in gamma-ray spectrometry with environmental samples are discussed, problems which - if disregarded - may also lead to erroneous activity values in the case of laboratory measurements. (orig./HP)

117

Technological Basis and Scientific Returns for Absolutely Accurate Measurements  

Science.gov (United States)

The 2006 NRC Decadal Survey fostered a new appreciation for societal objectives as a driving motivation for Earth science. Many high-priority societal objectives are dependent on predictions of weather and climate. These predictions are based on numerical models, which derive from approximate representations of well-founded physics and chemistry on space and timescales appropriate to global and regional prediction. These laws of chemistry and physics in turn have a well-defined quantitative relationship with physical measurement units, provided these measurement units are linked to international measurement standards that are the foundation of contemporary measurement science and standards for engineering and commerce. Without this linkage, measurements have an ambiguous relationship to scientific principles that introduces avoidable uncertainty in analyses, predictions, and improved understanding of the Earth system. Since the improvement of climate and weather prediction is fundamentally dependent on the improvement of the representation of physical processes, measurement systems that reduce the ambiguity between physical truth and observations represent an essential component of a national strategy for understanding and living with the Earth system. This paper examines the technological basis and potential science returns of sensors that make measurements that are quantitatively tied on-orbit to international measurement standards, and thus testable to systematic errors. This measurement strategy provides several distinct benefits. First, because of the quantitative relationship between these international measurement standards and fundamental physical constants, measurements of this type accurately capture the true physical and chemical behavior of the climate system and are not subject to adjustment due to excluded measurement physics or instrumental artifacts. In addition, such measurements can be reproduced by scientists anywhere in the world, at any time, by appeal to the scientific literature and protocols supported by the international community of measurement scientists. This link to the international measurement community provides an established link to a rigorous body of knowledge for the assessment of measurement uncertainty, which is crucial to societal objectives of a quantitative nature. Finally, because enhanced quantitative weather and climate prediction directly serve decision support structures that embody critical societal objectives, the credibility of these predictions is paramount. Since the foundation of credibility of any scientific theory is the underlying observational evidence, the link between these measurements and internationally recognized measurement standards is a critical component in the portfolio of Earth observing systems. Clearly measurements that are unerringly compatible with fundamental physical and chemical relationships offer distinct advantages for supporting improved prediction.

Dykema, J. A.; Anderson, J.

2011-12-01

118

Radiation protection. Radioactivity and radiation measurement  

International Nuclear Information System (INIS)

The text is aimed at environmental protection engineers, at people with an interest, be it vocationally or privately, in radioactivity and its measurement and at all teachers. The aim is an understandable and professional illustration of the themes radioactivity and radiation measurement, from a geophysicist approach. The common properties of the three ioniying radiation sources -radiographic, nuclear and cosmic radiation were highlighted. The physical, technical, metrological and geophysical aspects were dealt with more fundamentally than chemical and biological, as outlined in the detailed table of contents. In chapters 6, 7, and 8, as well as in the main volume, years of observations using, all measurement methods in practical radiometry are shown. Radon and radon detection are handled in detail. (orig./HP)

119

Measurement of absolute elastic differential cross-sections for positron-methane scattering  

International Nuclear Information System (INIS)

We have measured absolute elastic differential cross-sections (DCS's) for positrons scattered from methane over the energy range 6 to 200 eV at scattering angles from 30 to 135 degrees. We use a crossed beam experiment to obtain the DCS for electron-methane scattering at 20 eV which is then normalized at 90 degrees to the absolute measurements of Tanaka et al. This normalization factor is used to obtain absolute positron DCS's from our relative positron DCS measurements. Our absolute DCS's are in qualitative agreement with the calculations of Jain and Gianturco. Because of the similarity in shape between the total cross-section curves for positron-methane and positron-argon scattering, it is of interest to determine whether a resonance-like structure seen in the elastic DCS for positron-argon scattering at intermediate energies also appears in the DCS for positron-methane scattering. No such structure has yet been found

120

Absolute measurements of neutron cross sections. Progress report  

International Nuclear Information System (INIS)

In the photoneutron laboratory, we have completed a major refurbishing of experimental facilities and begun work on measurements of the capture cross section in thorium and U-238. In the 14 MeV neutron experimental bay, work continues on the measurement of 14 MeV neutron induced reactions of interest as standards or because of their technological importance. First results have been obtained over the past year, and we are extending these measurements along the lines outlined in our proposal of a year ago

 
 
 
 
121

Absolute measurement of ? emitters with a 4 ? counter  

International Nuclear Information System (INIS)

The object of this work is to investigate the conditions under which the activity of ?-emitting radionuclides may be measured with a maximum of precision, and as a result to study the relevant corrections. The various problems relating to activity measurements with a 4 ? counter have been examined successively: - comparison of 4 ?, GM and proportional counters; - study of the preparation of sources; - corrections on the counting of sources; - self-absorption; - correction for absorption. The precision obtained on these measurements varies from 1.2 to 3 per cent, with the result that the 4 ? counter can be considered a very satisfactory calibration instrument. (author)

122

Exchangeable Sequences Driven by an Absolutely Continuous Random Measure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Let S be a Polish space and (Xn : n = 1) an exchangeable sequence of S-valued random variables. Let an(·) = P( Xn+1 in · X1, . . . ,Xn) be the predictive measure and a a random probability measure on S such that an (weak) --> a a.s.. Two (related) problems are addressed. One is to give conditions for a << l a.s., where l is a (non random) sigma-finite Borel measure on S. Such conditions should concern the finite dimensional distributions L(X1, . . . ,Xn), n = 1, only. The other problem is t...

Berti, Patrizia; Pratelli, Luca; Rigo, Pietro

2011-01-01

123

Absolute measurement of ?-ray emitter radioelements by spectrometry (1963)  

International Nuclear Information System (INIS)

The proposed apparatus is composed of a lead collimator and a thallium sodium iodide activated scintillation detector. The geometrical solid angle is determined by the collimator, but the real solid angle is larger owing to the ?-ray filtration in the inner sides. The filtration coefficient to apply for obtention of the counting rate corresponding to the geometrical solid angle has been calculated and measured experimentally. ?-rays are scattered in the shielding of the scintillator what as a consequence to increase the counting rate. The scattering coefficient to apply for obtaining the real counting rate has been measured experimentally. The device efficiency for different ?-ray energies has been calculated and measured experimentally. A certain quantity of ?-ray emitter radioelements have been measured. The accuracy is 4 per cent. (author)

124

Absolute Bunch Length Measurement Using Coherent Diffraction Radiation  

Science.gov (United States)

The longitudinal electron beam properties are of crucial importance for many types of frontier accelerators, from storage rings to free electron lasers and energy recovery linacs. For the online control of the machine and its stable operation, nondestructive shot by shot bunch length measurements are needed. Among the various instrumentations proposed and installed in accelerators worldwide, the ones based on the measurement of the coherent radiation power represent the simplest and the more robust tools for operational control. The major limitation of these systems is that they usually can provide only relative bunch length estimation. In this Letter we present a novel experimental methodology to self-calibrate a simple equipment based on diffraction radiation from a gap providing a measurement of the second order moment of the longitudinal distribution. We present the theoretical basis of the proposed approach and validate it through a detailed campaign of measurements.

Veronese, Marco; Appio, Roberto; Craievich, Paolo; Penco, Giuseppe

2013-02-01

125

Development of a MEMS gyroscope for absolute angle measurement  

Science.gov (United States)

MEMS gyroscopes are typically designed to measure angular rate of rotation. A measurement of the angle itself is useful in many applications but cannot be obtained by integrating the angular rate due to the presence of bias errors which cause a drift. This thesis presents an innovative design for a vibrating gyroscope that can directly measure both angle and angular rate. The design is based on the principle of measuring the angle of free vibration of a suspended mass with respect to the casing of the device. Several critical challenges have to be handled before the theoretical sensing concept can be converted into a reliable practical sensor. These include compensating for the presence of dissipative forces, mismatched springs, cross-axis stiffness and transmission of rotary torque. These challenges are addressed by the development of a composite nonlinear feedback control system that compensates for each of the above effects and ensures that the mass continues to behave as a freely vibrating structure. Theoretical analysis and simulation results presented in this thesis show that the gyroscope can accurately measure both angle and angular rate for low bandwidth applications. A MEMS device is designed and fabricated to evaluate the real-world experimental performance of the sensor. It utilizes electrostatic comb actuators and capacitive sensing along both vibration axes fabricated by using Deep Reactive Ion Etching (DRIE) technique. Sensor noise is found to be a major impediment to successful implementation of the controller. The use of a Kalman filter enables some mitigation of noise and successful implementation of control, but the Kalman filter gain cannot be selected too high due to system stability limitations. In summary, the developed sensor provides a slightly improved measurement of angle compared to that obtained from integrating a commercially available rate gyroscope. However, due to noisy position measurements, it is unable to provide the drift free performance predicted by theory. Several lines of investigation are suggested in the thesis to study and solve the noise problem associated with the capacitive sensors. Simulations show that reducing the noise in the capacitive sensors will enable significantly superior angle measurement.

Piyabongkarn, Damrongrit

126

Measurement and analysis of radioactive substances  

International Nuclear Information System (INIS)

Here are gathered the abstracts presented to the 3. summer university of the year 2001 whose main themes were the destructive (5 conferences) and nondestructive (8 conferences) analyses applied to nuclear industry. The points of view of different organisms (as DSIN: Directorate for the Safety of Nuclear Installations, IPSN: Institute of Nuclear Protection and Safety, OPRI: Office of Protection against Ionizing Radiations, TUI: Institute for Transuranium Elements, COGEMA, EDF: Electric Utilities, ANDRA: French National Agency for Radioactive Waste Management, CRLC Val d'Aurelle, France) concerning the needs involved in nuclear facilities control, the methods of radionuclide speciation in use internationally, the measurements and analyses of radioactive substances are given too as well as some general concepts concerning 1)the laser-matter interaction 2)the ions production 3)the quality applied to the measurements and analyses 4)the standard in activity metrology. (O.M.)

127

Error calculations statistics in radioactive measurements  

International Nuclear Information System (INIS)

Basic approach and procedures frequently used in the practice of radioactive measurements.Statistical principles applied are part of Good radiopharmaceutical Practices and quality assurance.Concept of error, classification as systematic and random errors.Statistic fundamentals,probability theories, populations distributions, Bernoulli, Poisson,Gauss, t-test distribution,?2 test, error propagation based on analysis of variance.Bibliography.z table,t-test table, Poisson index ,?2 test

128

Absolute density measurements by dual sinker magnetic levitation densimeter  

Science.gov (United States)

The use of a magnetic levitation densimeter (MLD) currently represents the most sensitive way of measuring fluid density for a wide range of temperature and pressure conditions. However, due to magnetic force transmission errors, the accuracy of this approach is limited to approximately 100 ppm in density. Here, the authors propose an improved method to eliminate the uncertainty caused by magnetic forces acting on fluids based on the use of dual sinkers and control of the magnetic coupling's levitation height. The technique cuts out almost all force transmission errors and enables a level of density measurement precision better than 1 ppm. A new high-sensitivity MLD system was developed using a novel sinker exchange mechanism with a magnetic coupling. Single-crystal silicon and germanium were selected as the sinker materials because of their outstanding performance in terms of isotropy, stability and universality of thermophysical properties. A number of tests to check the measurement performance of the MLD were conducted by the National Metrology Institute of Japan. The experimental results for n-tridecane are also presented in this paper.

Kayukawa, Y.; Kano, Y.; Fujii, K.; Sato, H.

2012-08-01

129

Cross-section measurements for radioactive samples  

Energy Technology Data Exchange (ETDEWEB)

The measurement of (n,p), (n,..cap alpha..) and (n,..gamma..) cross sections for radioactive nuclei is of interest to both nuclear physics and astrophysics. For example, using these reactions, properties of levels in nuclei at high excitation energies, which are difficult or impossible to study using other reactions, can be investigated. Also, reaction rates for both big-bang and stellar nucleosynthesis can be obtained from these measurements. In the past, the large background associated with the sample activity limited these types of measurements to radioisotopes with very long half-lives. The advent of the low-energy, high-intensity neutron source at the Los Alamos Neutron Scattering CEnter (LANSCE) has greatly increased the number of nuclei which can be studied. Examples of (n,p) measurements on samples with half lives as short as fifty-three days will be given. The nuclear physics and astrophysics to be learned from these data will be discussed. Additional difficulties are encountered when making (n,..gamma..) rather than (n,p) or (n,..cap alpha..) measurements. However, with a properly-designed detector, and the high peak neutron intensities now available, (n,..gamma..) measurements can be made for nuclei with half lives as short as several months. Progress on the Los Alamos (n,..gamma..) cross-section measurement program for radioactive samples will be discussed. 39 refs., 7 figs.

Koehler, P.E.; O' Brien, H.A.

1988-01-01

130

Method for the absolute measurement of photon energies  

Energy Technology Data Exchange (ETDEWEB)

We present a Monte Carlo study of the Compton scattering of high energy photons on atomic electrons of a {sup 27} Al target. The calculation was done in order to estimate the potentiality of using this reaction for high precision measurements of photon energies. A computer code was developed, based on relativistic reaction kinematics in impulse approximation, accounting for the final atom kinetic energy and the internal motion of the atomic electrons. The code includes the rescattering of the emitted electron in the target material, and allows to study the influence of several geometrical parameters of the system on the accuracy with which the initial photon energy is determined. The results of the simulations show that, for high intensity photon beams, the energy of the photons can be determined with a relative accuracy of 10{sup -3}. (author)

Likhachev, V.P.; Arruda Neto, J.D.T.; Deppman, A.; Cruz, M.T.F.; Carvalho, W.R.; Gavrikov, V.B.; Martins, M.N.; Mesa, J. [Universidade de Sao Paulo, SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Margarian, A. [Yerevan Institute of Nuclear Physics (Armenia)

2001-07-01

131

Accreditation of laboratories measuring environmental radioactivity  

International Nuclear Information System (INIS)

The radiological state of our environment is a strong concern for the public. The measurement of the radioactivity is an answer to this concern. The French National Network for the Measurement of Environmental Radioactivity (www.mesure-radioactivite.fr.) centralizes all the results of measurements of radioactivity in the environment on the national territory. The web-site provide an easy access to the results. Nevertheless it is needed to ensure the quality of the results obtained by the laboratories before reporting them to the web-site. A new laboratory approval system was created through an ASN decision (decision no 2008-DC-0099 of 29 april 2008), taking into account the new prerogatives granted to ASN by Act of 13 june 2006 and the modification of Public Heath Code towards the protection of individuals against the risks arising from ionising radiations in november 2007. This paper presents this new regulation by specifying the nature of the laboratories concerned and the field of approval with more than forty different kinds of approval, relating to all the environmental compartments and various radionuclide measurements (alpha, beta or gamma emitters). It also details the procedure of approval which in particular include the conformity of the practices of the laboratory to the requirements of standard ISO/CEI 17025 and the regular participation to intercomparison tests organised by IRSN. It draws up the assessment of the laboratories approved on 1 January 2010 anlaboratories approved on 1 January 2010 and analyzes the distribution of approvals according to the statute of laboratories, the measurement categories and the nature of the measured environmental samples. (author)

132

National network of radioactivity measurement in environment  

International Nuclear Information System (INIS)

This document constitutes the report of management for the year 2006 of the national network of measurement of radioactivity in environment, instituted by the article R.1333-11 of the Public Health code. According to the 5. of the decree of 27. june 2005, the Institute of radiation protection and nuclear safety (I.R.S.N.) has for mission to write every year a report of management of the national network of radioactivity measurement in environment. This report has for principal objectives: to do an evaluation on organisation and functioning of the piloting committee; to realize a synthesis on the different tasks lead by the working groups; as well as on the human and financial resources devoted to this project; to debrief on the development project of the national network information system. This report must allow to the network actors, as to the professional people and the public, to understand the functioning of the national network and the process implemented for the development of centralization, management and public diffusion tools, of the radioactivity data in environment. The year 2006 was marked by the opening of an Internet gate of the national network. (N.C.)

133

Absolute Measurement of 14C Activity by Internal Proportional Counters  

International Nuclear Information System (INIS)

14CO22 was obtained by decomposing carbonate with sulphuric acid heated to boiling point, after which it was mixed with CH4 in a reserve flask. Three brass internal proportional counters, differing only in length, were filled with this mixture. The counters were connected to the electronic equipment in the usual arrangement. The equipment dead time was determined by means of a modified two-source method, and the total volume of the equipment was obtained from the isothermic expansion of methane from a flask whose volume, together with that of the counters, had been determined by weighing a water filling. The wall effect was determined by measuring a 14CO2 + CH4 mixture at different pressures and by extrapolation to reciprocal pressure zero value; it was discovered that the wall-effect correction did not differ significantly from zero. The end effect was compensated for by using counters of different lengths so that the difference in plateau slope also did not differ significantly from zero. By the t-test power function it was estimated that the maximal error on a 0.01 significance level, caused by neglecting the wall-effect correction, amounted to ± 0.85% due to the end-effect correction (± 0.62% for the equipment used) having been neglected. The relation between wall, end and discrimination effects is discussed, and, in conclusion, the maximal errors from other sources are estimated; the total maxima sources are estimated; the total maximal error on a 0.01 significance level of the standard solution activity is computed as equal to ± 1.1%. (author)

134

Environmental radioactivity measurements of Egyptian soils  

International Nuclear Information System (INIS)

Soil and vegetation samples fro m33 sites within the northwestern area of the River Nile delta in Egypt have been analyzed for natural and man-made radioactivity. Gamma-ray spectrometric measurements were performed where 214Bi and 214Pb were used for 238U-series determinations, while 208Tl and 228Ac were used for 232Th-series determinations. In addition, alpha-spectrometric measurements were also performed for the determination of different isotopes of uranium and plutonium. Other parameters examined included the determination of radium equivalent activities and relationship between the gamma-radiation values and subsequent dose level determinations and the soil types. (author)

135

The Implications for Higher-Accuracy Absolute Measurements for NGS and its GRAV-D Project  

Science.gov (United States)

Absolute and relative gravity measurements play an important role in the work of NOAA's National Geodetic Survey (NGS). When NGS decided to replace the US national vertical datum, the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project added a new dimension to the NGS gravity program. Airborne gravity collection would complement existing satellite and surface gravity data to allow the creation of a gravimetric geoid sufficiently accurate to form the basis of the new reference surface. To provide absolute gravity ties for the airborne surveys, initially new FG5 absolute measurements were made at existing absolute stations and relative measurements were used to transfer those measurements to excenters near the absolute mark and to the aircraft sensor height at the parking space. In 2011, NGS obtained a field-capable A10 absolute gravimeter from Micro-g LaCoste which became the basis of the support of the airborne surveys. Now A10 measurements are made at the aircraft location and transferred to sensor height. Absolute and relative gravity play other roles in GRAV-D. Comparison of surface data with new airborne collection will highlight surface surveys with bias or tilt errors and can provide enough information to repair or discard the data. We expect that areas of problem surface data may be re-measured. The GRAV-D project also plans to monitor the geoid in regions of rapid change and update the vertical datum when appropriate. Geoid change can result from glacial isostatic adjustment (GIA), tectonic change, and the massive drawdown of large scale aquifers. The NGS plan for monitoring these changes over time is still in its preliminary stages and is expected to rely primarily on the GRACE and GRACE Follow On satellite data in conjunction with models of GIA and tectonic change. We expect to make absolute measurements in areas of rapid change in order to verify model predictions. With the opportunities presented by rapid, highly accurate absolute gravimetry, we expect that GRAV-D may be affected in a number of ways. 1) Areas requiring re-measurement as a result of poor quality data or temporal change could be measured with such a new meter. With a meter capable of field measurement with observation times that are very short, surveys previously conducted only with the relative meters could be performed with the absolute meter with no loss of time and a significant increase in accuracy. 2) Regions of rapid change due to hydrological change associated with aquifers could be measured and re-measured rather quickly. Such accuracy may provide more accurate snapshots of the aquifers over time. 3) NGS conducts absolute gravity comparisons at its Table Mountain facility for validating the performance of absolute meters through their co-located operation at gravity piers. An increase in accuracy of an order of magnitude may change the entire nature of absolute meter performance evaluation.

Childers, V. A.; Winester, D.; Roman, D. R.; Eckl, M. C.; Smith, D. A.

2013-12-01

136

High accuracy, absolute, cryogenic refractive index measurements of infrared lens materials for JWST NIRCam using CHARMS  

CERN Document Server

The refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF2, and ZnSe. In order to provide the instrument's optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA's Goddard Space Flight Center (GSFC), densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Data reduction methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented for selected wavelengths and temperatures along with estimates of index uncertainty. Coefficients for temperature-dependent Sellmeier fits of measured index are also presented with an example of their usage to predict absolute index ...

Leviton, Douglas B; Kvamme, Todd

2008-01-01

137

Direct frequency comb measurements of absolute optical frequencies and population transfer dynamics  

CERN Document Server

A phase-stabilized femtosecond laser comb is directly used for high-resolution spectroscopy and absolute optical frequency measurements of one- and two-photon transitions in laser-cooled \\rb atoms. Absolute atomic transition frequencies, such as the 5S$_{1/2}$ F=2 \\ra 7S$_{1/2}$ F"=2 two-photon resonance measured at 788 794 768 921(44) kHz, are determined without \\textit{a priori} knowledge about their values. Detailed dynamics of population transfer driven by a sequence of pulses are uncovered and taken into account for the measurement of the 5P states via resonantly enhanced two-photon transitions.

Marian, A; Felinto, D; Ye, J; Marian, Adela; Stowe, Matthew C.; Felinto, Daniel; Ye, Jun

2005-01-01

138

Absolute measurement of the DT primary neutron yield on the National Ignition Facility  

Directory of Open Access Journals (Sweden)

Full Text Available The measurement of the absolute neutron yield produced in inertial confinement fusion target experiments conducted on the National Ignition Facility (NIF is essential in benchmarking progress towards the goal of achieving ignition on this facility. This paper describes three independent diagnostic techniques that have been developed to make accurate and precise DT neutron yield measurements on the NIF.

Leeper R.J.

2013-11-01

139

Automatic absolute measurement of 57Co activity by 4?X(L.S)-? coincidence  

International Nuclear Information System (INIS)

The YS-01 type liquid scintillation counter equipped with common auto-counting and data processing device is presented. The specific activity of 57Co solution is measured absolutely by 4?X(L.S)-? coincidence method. Total uncertainty (3?) of measured result is less than 1.26%

140

Determination of total body calcium by prompt gamma neutron activation analysis: absolute in vivo measurements.  

Science.gov (United States)

Sequential TBCa measurements using the prompt gamma ray technique are firmly established and a number of patient groups are under investigation. A technique has been proposed for the absolute measurement of TBCa based upon the use of TBCl as an internal standard. Further work is needed to establish the validity of the method, but the initial results are encouraging. PMID:2088291

Ryde, S J; Morgan, W D; Compston, J E; Williams, A J; Evans, C J; Sivyer, A; Dutton, J

1990-01-01

 
 
 
 
141

Absolute spectral responsivity measurements of solar cells by a hybrid optical technique.  

Science.gov (United States)

An irradiance mode, absolute differential spectral response measurement system for solar cells is presented. The system is based on combining the monochromator-based approach of determining the power mode spectral responsivity of cells with an LED-based measurement to construct a curve representing the light-overfilled absolute spectral response of the entire cell. This curve can be used to predict the short-circuit current (I(sc)) of the cell under the AM 1.5 standard reference spectrum. The measurement system is SI-traceable via detectors with primary calibrations linked to the NIST absolute cryogenic radiometer. An uncertainty analysis of the methodology places the relative uncertainty of the calculated I(sc) at better than ±0.8%. PMID:23872765

Hamadani, Behrang H; Roller, John; Dougherty, Brian; Persaud, Fiona; Yoon, Howard W

2013-07-20

142

Sounding rocket measurement of the absolute solar EUV flux utilizing a silicon photodiode  

Science.gov (United States)

A newly developed stable and high quantum efficiency silicon photodiode was used to obtain an accurate measurement of the integrated absolute magnitude of the solar extreme UV photon flux in the spectral region between 50 and 800 A. The adjusted daily 10.7-cm solar radio flux and sunspot number were 168.4 and 121, respectively. The unattenuated absolute value of the solar EUV flux at 1 AU in the specified wavelength region was 6.81 x 10 to the 10th photons/sq cm per s. Based on a nominal probable error of 7 percent for National Institute of Standards and Technology detector efficiency measurements in the 50- to 500-A region (5 percent on longer wavelength measurements between 500 and 1216 A), and based on experimental errors associated with the present rocket instrumentation and analysis, a conservative total error estimate of about 14 percent is assigned to the absolute integral solar flux obtained.

Ogawa, H. S.; Mcmullin, D.; Judge, D. L.; Canfield, L. R.

1990-01-01

143

Combined absolute and relative gravity measurement for microgravity monitoring in Aso volcanic field  

Science.gov (United States)

Absolute measurement with a portable A10-017 absolute gravimeter at some benchmarks in the Aso volcanic field are valuable for reducing uncertainties of regional gravity variations and will be useful for delineating the long term trends of gravity changes. A10 absolute gravimeter is a new generation of portable absolute instrument and has accuracy 10 microGal. To further the development of a high precision gravity data, we also conducted measurement using two relative gravimeter (Scintrex CG-5 [549] and LaCoste type G-1016) to be combined with an A10 absolute gravimeter. The using absolute gravimeter along with relative gravimeter can reduce drift correction factor and improve the result of gravity change data in microgravity monitoring. Microgravity monitoring is a valued tool for mapping the redistribution of subsurface mass and for assessing changes in the fluid as a dynamic process in volcanic field. Gravity changes enable the characterization of subsurface processes: i.e., the mass of the intrusion or hydrothermal flow. A key assumption behind gravity monitoring is that changes in earth's gravity reflect mass-transport processes at depth [1]. The absolute gravity network was installed at seven benchmarks using on May 2010, which re-occupied in October 2010, and June 2011. The relative gravity measurements were performed at 28 benchmarks in one month before the eruption on May 2011 and then followed by series of gravity monitoring after the eruption in every three to five months. Gravity measurements covered the area more than 60 km2 in the west side of Aso caldera. Some gravity benchmarks were measured using both absolute and relative gravimeter and is used as the reference benchmarks. In longer time period, the combined gravity method will improve the result of gravity change data for monitoring in the Aso volcanic field. As a result, the gravity changes detected the hydrothermal flow in the subsurface which has a correlation to water level fluctuation in the crater. Large residual gravity changes between the surveys of absolute and relative gravimeter are found at benchmarks around Nakadake crater. Keywords: Microgravity monitoring, Aso volcanic field References [1] Battaglia, M., J. Gottsmann, D. Carbone, and J. Fernandez, 2008, 4D volcano gravimetry: Geophysics, vol. 73 no.6, p. WA3-WA18.

Sofyan, Yayan; Nishijima, Jun; Yoshikawa, Shin; Fujimitsu, Yasuhiro; Kagiyama, Tsuneomi; Fukuda, Yoichi

2014-05-01

144

Thorium target thickness from radioactivity measurement  

International Nuclear Information System (INIS)

For a study of collisions between 184W and 232Th, thorium targets on thin backings were necessary. These targets could readily be prepared by electrodeposition from an alcohol solution. In the present investigation the quantity of thorium plated out as a function of deposition time was determined and then for each sample, the ?-particle radioactivity of the layer was measured. The result is a graph which shows the correspondence between the weight of thorium and the activity of the target. This relationship has been very useful to determine deposit thickness on thin backings such as aluminium (50 ?g/cm2) or carbon (20 ?g/cm2). (orig.)

145

Absolute rate measurements of two-photon process of gases, liquids, and solids  

International Nuclear Information System (INIS)

Due to rapid improvements in high-power laser performance, two-photon absorption processes have become a very useful tool for studying the molecular structures of various gases, liquids and solids. However, measurements of absolute two-photon absorption cross sections were more or less ignored previously because of their small size. In this work, we obtained not only the two-photon absorption spectra, but also measurements of their absolute cross sections for various gases, liquids, and solids. 8 refs., 1 fig., 1 tab

146

Comparative Test of Two Methods of Quantum Efficiency Absolute Measurement Based on Squeezed Vacuum Direct Detection  

CERN Document Server

We realize and test in experiment a method recently proposed for measuring absolute quantum efficiency of analog photodetectors. Similarly to the traditional (Klyshko) method of absolute calibration, the new one is based on the direct detection of two-mode squeezed vacuum at the output of a traveling wave OPA. However, in the new method one measures the difference-photocurrent variance rather than the correlation function of photocurrents (number of coincidences), which makes the technique applicable for high-gain OPA. In this work we test the new method versus the traditional one for the case of photon-counting detectors where both techniques are valid.

Agafonov, I N; Iskhakov, T Sh; Penin, A N; Rytikov, G O; Shumilkina, O A

2010-01-01

147

Temperature-dependent absolute refractive index measurements of synthetic fused silica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from temperatures ranging from 30 to 310 K at wavelengths from 0.4 to 2.6 microns with an absolute uncertainty of +/-1 x 10^-5. Statistical variations in derived values of the thermo-optic coefficient (dn/dT) are at the +/-2 x 10^-8/K level. Gr...

Leviton, Douglas B.; Frey, Bradley J.

2008-01-01

148

In situ measurement of leaf chlorophyll concentration: analysis of the optical/absolute relationship.  

Science.gov (United States)

In situ optical meters are widely used to estimate leaf chlorophyll concentration, but non-uniform chlorophyll distribution causes optical measurements to vary widely among species for the same chlorophyll concentration. Over 30 studies have sought to quantify the in situ/in vitro (optical/absolute) relationship, but neither chlorophyll extraction nor measurement techniques for in vitro analysis have been consistent among studies. Here we: (1) review standard procedures for measurement of chlorophyll; (2) estimate the error associated with non-standard procedures; and (3) implement the most accurate methods to provide equations for conversion of optical to absolute chlorophyll for 22 species grown in multiple environments. Tests of five Minolta (model SPAD-502) and 25 Opti-Sciences (model CCM-200) meters, manufactured from 1992 to 2013, indicate that differences among replicate models are less than 5%. We thus developed equations for converting between units from these meter types. There was no significant effect of environment on the optical/absolute chlorophyll relationship. We derive the theoretical relationship between optical transmission ratios and absolute chlorophyll concentration and show how non-uniform distribution among species causes a variable, non-linear response. These results link in situ optical measurements with in vitro chlorophyll concentration and provide insight to strategies for radiation capture among diverse species. PMID:24635697

Parry, Christopher; Blonquist, J Mark; Bugbee, Bruce

2014-11-01

149

Absolute measurements of collisional ionization of xenon atoms in well-defined high Rydberg states  

International Nuclear Information System (INIS)

Measurements of the absolute cross sections for Xe+ production in collisions betweeen xenon atoms in a single well-defined high Rydberg state vertical-barnf= and SF6 are reported and are approx.10-11 cm2 for 25 6 interaction, with the Xe+ ion core playing a minor role

150

Low geometry counter for the absolute measurement of the activity of alpha-emitting sources  

International Nuclear Information System (INIS)

A low-geometry counter is described which allows the absolute determination of the activity for alpha-emitting sources. A Si implanted detector is used to obtain the spectrum of the sample. Two samples are measured with this counter and a 2 ? gridded ion chamber. The results an their uncertainties for both instruments are discussed. (Author)

151

Lifetime measurements and absolute oscillator strengths for single ionized thorium (ThII)  

International Nuclear Information System (INIS)

Using collinear fast cw dye laser modulation spectroscopy accurate lifetimes in ThII have been measured. Together with known branching ratios these lifetimes have allowed the determination of absolute oscillator strengths for ThII. This element is of astrophysical interest as a chronometer for stellar and galaxy evolution, with oscillator strength playing an important role in synthesis of stellar spectral data. (orig.)

152

Absolute (e, 2e) differential cross section measured in coplanar conditions: He  

International Nuclear Information System (INIS)

The first measurements of the absolute (e, 2e) five times differential cross section in coplanar symmetric conditions on He are reported. Incident energy is varied from 200 to 4000 eV in order to test different theoretical models. (Auth.)

153

A Monte Carlo Comparison of Measures of Relative and Absolute Monitoring Accuracy  

Science.gov (United States)

Researchers studying monitoring accuracy currently use two different indexes to estimate accuracy: relative accuracy and absolute accuracy. The authors compared the distributional properties of two measures of monitoring accuracy using Monte Carlo procedures that fit within these categories. They manipulated the accuracy of judgments (i.e., chance…

Nietfeld, John L.; Enders, Craig K; Schraw, Gregory

2006-01-01

154

Superharp: A wire scanner with absolute position readout for beam energy measurement at CEBAF  

Energy Technology Data Exchange (ETDEWEB)

Superharp is an upgrade CEBAF wire scanner with absolute position readout from shaft encoder. As high precision absolute beam position probe ({Delta}x {approximately} 10{mu}m), three pairs of superharps are installed at the entrance, the mid-point, and the exit of Hall C arc beamline in beam switch yard, which will be tuned in dispersive mode as energy spectrometer performing 10{sup {minus}3} beam energy measurement. With dual sensor system: the direct current pickup and the bremsstrahlung detection electronics, beam profile can be obtained by superharp at wide beam current range from 1 {mu}A to 100 {mu}A.

Yan, C.

1994-09-07

155

Hydrological effects on gravity measurements at the Canadian Absolute Gravity Site  

Science.gov (United States)

The Canadian Gravity Standardization Net (CGSN), a network of primary and secondary gravity sites, provides the reference linkage for regional and local gravity surveys performed in different places and at different epochs in Canada. Maintained over the last five decades, CSGN has produced a reliable determination of the gravitational potential as well as associated temporal variations upon the Earth's surface. As part of CGSN more than 60 absolute gravity stations have been established across Canada. This network of absolute gravity sites is designed to provide absolute control for the CGSN and to continue the monitoring of temporal variations resulting from glacial isostatic adjustment, tectonic deformation and other processes. Additionally, monitoring of temporal gravity change rates at key, continuous GPS sites is an important step towards maintenance of an integrated reference system. The primary site for evaluating the stability of the absolute gravimeters for this network is the Canadian Absolute Gravity Site (CAGS), located near Ottawa at Cantley, Quebec (Lat. 45.585°N, Long. 75.807°W). CAGS is the base station for all JILA-2 and A10-003 field measurements as well as housing the Canadian Superconducting Gravimeter Installation (CSGI) which is contributing continuous data to the Global Geodynamics Project (1997-2003). Although owned by a consortium of Canadian universities, superconducting gravimeter GWR12 is operated with the assistance of the Geodetic Survey Division and provides a data stream which can be compared with frequent, repeated absolute gravity measurements. Additional CAGS/CSGI on-site data include: continuous water-level measurements from shallow (10m) and deep (120m) wells, observations from meteorological instrumentation, and continuous Global Positioning System (GPS) observations. Using the data available from the CAGS, we have begun to carry out a systematic self-consistent and complete synthesis, evaluation and interpretation of all available absolute gravity data collected over the last decade. Data from superconducting gravimeter GWR12, coupled with these absolute measurements, will be used to test models of seasonal variations in gravity at the CAGS base station due to groundwater effects identified in earlier work (e.g. Bower and Courtier, 1998).

Henton, J. A.; Liard, J. O.; Lambert, A.; Gagnon, C.; Courtier, N.

2003-04-01

156

New absolute distance measurement technique with a self-mixing interferometer  

International Nuclear Information System (INIS)

A new compact self-aligned noncontact range finder is described. It uses the self-mixing effect inside a laser diode. Double modulation technique is proposed to improve the measurement accuracy. Wavelength modulation (WM) of the laser beam is obtained by modulating the injection current of the laser diode. Phase modulation (PM) of the laser beam is obtained by an electro-optic crystal (EOC) in the external cavity. Absolute distance of the external target is determined by Fourier analysis method. Experimental results show that an accuracy of ±0.3mm can be achieved for absolute distance ranging from 277mm to 477mm

157

Absolute phase retrieval for defocused fringe projection three-dimensional measurement  

Science.gov (United States)

Defocused fringe projection three-dimensional technique based on pulse-width modulation (PWM) can generate high-quality sinusoidal fringe patterns. It only uses slightly defocused binary structured patterns which can eliminate the gamma problem (i.e. nonlinear response), and the phase error can be significantly reduced. However, when the projector is defocused, it is difficult to retrieve the absolute phase from the wrapped phase. A recently proposed phase coding method is efficient for absolute phase retrieval, but the gamma problem leads this method not so reliable. In this paper, we use the PWM technique to generate fringe patterns for the phase coding method. The gamma problem of the projector can be eliminated, and correct absolute phase can be retrieved. The proposed method only uses two grayscale values (0's and 255's), which can be used for real-time 3D shape measurement. Both simulation and experiment demonstrate the performance of the proposed method.

Zheng, Dongliang; Da, Feipeng

2014-02-01

158

Measurement of Absolute Hadronic Branching Fractions of D_s Mesons  

CERN Document Server

We report preliminary measurements of absolute hadronic branching fractions of Ds mesons determined using a double tag technique. These measurements are from 195 pb^{-1} of e+e- collisions recorded at center of mass energies near 4.17 GeV with the CLEO-c detector at CESR. We obtain absolute branching fractions for Ds+ decays to KS0 K+, K- K+ pi+, K- K+ pi+ pi-, pi+ pi+ pi-, pi+ eta, and pi+ etaprime. We discuss the problems inherent in measuring accurately the branching fraction for Ds+ to phi pi+, which is often used as a reference mode for measurement of other Ds+ branching fractions, and provide a measurement of a branching fraction that may be useful for this purpose.

Adam, N; Berkelman, K; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Onyisi, P U E; Patterson, J R; Peterson, D; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Weinberger, M; Athar, S B; Patel, R; Potlia, V; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; White, E J; Wiss, J; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Smith, A; Zweber, P; Dobbs, S; Metreveli, Z V; Seth, K K; Tomaradze, A G; Ernst, J; Severini, H; Dytman, S A; Love, W; Savinov, V; Aquines, O; Li, Z; López, A; Mehrabyan, S S; Méndez, H; Ramírez, J; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Coan, T E; Gao, Y S; Liu, F; Artuso, M; Blusk, S; Butt, J; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Briere, R A; Brock, I; Chen, J; Ferguson, T; Tatishvili, G T; Vogel, H; Watkins, M E; Rosner, J L

2006-01-01

159

High Accuracy, Absolute, Cryogenic Refractive Index Measurements of Infrared Lens Materials for JWST NIRCam using CHARMS  

Science.gov (United States)

The current refractive optical design of the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF, BaF2, and ZnSe. In order to provide the instrument s optical designers with accurate, heretofore unavailable data for absolute refractive index based on actual cryogenic measurements, two prismatic samples of each material were measured using the cryogenic, high accuracy, refraction measuring system (CHARMS) at NASA GSFC, densely covering the temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6 microns. Measurement methods are discussed and graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient for these three materials are presented along with estimates of uncertainty. Coefficients for second order polynomial fits of measured index to temperature are provided for many wavelengths to allow accurate interpolation of index to other wavelengths and temperatures.

Leviton, Douglas; Frey, Bradley

2005-01-01

160

Radioactivity measurements for some ophthalmic glasses  

International Nuclear Information System (INIS)

The main aim of the present work is to implant the latest ICRP/IAEA recommendations related to exemption and clearness to the Ophthalmic Glass. As consumer product, glass lenses may contain trace quantities of uranium, thorium and potassium. Glass lenses under investigation were monitored for the detection of gamma rays and beta particles using radiation measuring devices. Using high purity germanium detector radioactivity concentration was estimated in Bq/kg. Activity concentration of 226 Ra, Th-232 and K-40 were determined using the energy gamma lines of 2l4Pb (352 keV), 212Pb (238 keV) and 1460 keV gamma line for 40K respectively .Experimental results showed that radioactivity concentration for radium -226 varies from 0.19 to 4.98 Bq/kg of radium-226, from to 0.18 to 2.83 Bq/kg for thorium -232 and from 0.8 to 1.13 Bq/kg for potassium. Implementing new ICRP recommendation of exemption and clearness indicated that several Ophthalmic Glass should not be in use

 
 
 
 
161

Ethernet-based automation in radioactivity measurements  

Energy Technology Data Exchange (ETDEWEB)

The paper describes an integrated radioactivity measurements laboratory involved in a New York State program of monitoring environmental radioactivity and bioassay samples. The laboratory is set up as a comprehensive Ethernet network that integrates radiation detectors, electronics hardware components as well as software automation and communications. Two DEC VAXstations 3100 and 3200 are central to the system. The VAXstation 3100 runs the Canberra/Nuclear Data Genie data-acquisition program. The Acquisition Interface Modules interface the ADCs to the Ethernet. Using the DEC Pathworks, the VAXstation 3100 is also a server for the Ethernet-based network of several 486 and 386 PCs. A designated PC can display the Genie acquisition window, in addition to the main window at VAXstation 3100. Another PC collects data from several NaI detectors using the Oxford/Nucleus DMR-II program. The paper also describe the plans for the future upgrades such as installation of VAXstation 4000/90 as well as interfacing the proportional counters and surface barrier detectors to the network.

Schwenker, C.D.; Daly, J.C. [Wadsworth Center for Laboratories and Research, Albany, NY (United States); Semkow, T.M.; Kitto, M.E. [State Univ. of New York, Albany, NY (United States)

1993-12-31

162

Ethernet-based automation in radioactivity measurements  

International Nuclear Information System (INIS)

The paper describes an integrated radioactivity measurements laboratory involved in a New York State program of monitoring environmental radioactivity and bioassay samples. The laboratory is set up as a comprehensive Ethernet network that integrates radiation detectors, electronics hardware components as well as software automation and communications. Two DEC VAXstations 3100 and 3200 are central to the system. The VAXstation 3100 runs the Canberra/Nuclear Data Genie data-acquisition program. The Acquisition Interface Modules interface the ADCs to the Ethernet. Using the DEC Pathworks, the VAXstation 3100 is also a server for the Ethernet-based network of several 486 and 386 PCs. A designated PC can display the Genie acquisition window, in addition to the main window at VAXstation 3100. Another PC collects data from several NaI detectors using the Oxford/Nucleus DMR-II program. The paper also describe the plans for the future upgrades such as installation of VAXstation 4000/90 as well as interfacing the proportional counters and surface barrier detectors to the network

163

TDCR method for 3H, 14C radioactivity measurement  

International Nuclear Information System (INIS)

TDCR counting efficiency measurement technique has been realized by using triple tube liquid scintillation detecting system, and the absolute measurement of the activity of 3H, 14C has been finished. (author)

164

Radioactivity Measurements at PTB and the Linkage to Environmental Radioactivity Monitoring  

International Nuclear Information System (INIS)

Full text: Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of Germany. The work currently performed at PTB is presented and the linkage to the nation-wide environmental radioactivity monitoring system is described by some examples: (i) radioactivity standards, (ii) intercomparisons in the framework of the German 'Integrated Measurement and Information System' (IMIS) for environmental radioactivity monitoring, (iii) radon reference chamber for measurement of radon and radon progenies, (iv) long-term measurement series of radioactive traces in ground-level air in Braunschweig, (v) current research and development activities. (author)

165

Production and trapping of carbon clusters for absolute mass measurements at ISOLTRAP  

CERN Document Server

Singly-charged carbon clusters C/sub n//sup +/ (n >or= 1) have been produced by laser-induced desorption and fragmentation of C/sub 60/ fullerenes and have been injected into and stored in the Penning trap system of the ISOLTRAP mass spectrometer at ISOLDE/CERN. The present study is the first step to extend the until now direct mass measurements at ISOLTRAP to absolute mass measurements by using clusters of /sup 12/C. (10 refs).

Scheidenberger, C; Herfurth, F; Kellerbauer, A G; Kluge, H J; Koizumi, M; Schwarz, S; Schweikhard, L

2002-01-01

166

Polarized H- Jet Polarimeter For Absolute Proton Polarization Measurements in RHIC  

International Nuclear Information System (INIS)

Status of the H-jet polarimeter development is reviewed. A number of design issues are discussed including vacuum system, integration into the RHIC storage ring, scattering chamber, and uniform vertical holding field magnet design. The absolute proton polarization of the atomic hydrogen-jet target will be measured to 3% accuracy by a Breit- systematic error contribution to the jet-target polarization measurements is also discussed

167

Measurements of absolute gamma-ray emission probabilities in the decay of 233Pa  

International Nuclear Information System (INIS)

Gamma-ray emission probabilities from the ?- decay of 233Pa were measured with planar (LEPS) and coaxial Ge detectors. A 233Pa source was produced after radiochemical separation from a 237Np sample in which the parent (237Np) and daughter (233Pa) nuclides were in secular equilibrium. Absolute ?-ray emission probabilities per 100 ? decays of the parent nuclide 237Np were also measured in conjunction with the ?- and ?-ray spectroscopy techniques.

168

A study on the development of anticoincidence counting system for absolute activity measurement  

International Nuclear Information System (INIS)

Anticoincidence counting system is developed for absolute activity measurement of ?, ? emitting nuclides. In fabrication of this system live timing priciple is used to resolve the problems of dead time and resolving time correction which would occur in the conventional counting systems. The specific activity 60Co is measured using the system produced in this study. This result is compared with that obtained with coincidence counting system. The comparison shows that the differences between two results are within 0.4%. (Author)

169

Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature  

Science.gov (United States)

At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

Schmuck, S.; Fessey, J.; Gerbaud, T.; Alper, B.; Beurskens, M. N. A.; de la Luna, E.; Sirinelli, A.; Zerbini, M.; JET-EFDA Contributors

2012-12-01

170

Laser induced deflection (LID) method for absolute absorption measurements of optical materials and thin films  

Science.gov (United States)

We use optimized concepts to measure directly low absorption in optical materials and thin films at various laser wavelengths by the laser induced deflection (LID) technique. An independent absolute calibration, using electrical heaters, is applied to obtain absolute absorption data without the actual knowledge of the photo-thermal material properties. Verification of the absolute calibration is obtained by measuring different silicon samples at 633 nm where all laser light, apart from the measured reflection/scattering, is absorbed. Various experimental results for bulk materials and thin films are presented including measurements of fused silica and CaF2 at 193 nm, nonlinear crystals (LBO) for frequency conversion and AR coated fused silica for high power material processing at 1030 nm and Yb-doped silica raw materials for high power fiber lasers at 1550 nm. In particular for LBO the need of an independent calibration is demonstrated since thermal lens generation is dominated by stress-induced refractive index change which is in contrast to most of the common optical materials. The measured results are proven by numerical simulations and their influence on the measurement strategy and the obtained accuracy are shown.

Mühlig, Christian; Bublitz, Simon; Paa, Wolfgang

2011-05-01

171

Radioactivity measurements applied to glaciers and lake sediments  

International Nuclear Information System (INIS)

The behaviour of glaciers, polar ice-caps and lakes can be studied by means of natural and artificial radioactivity measurements conducted on snow (Alps, Arctic and Antarctic) and sediments samples. The nuclear decay of elements (210Pb and 238U filiation products) and nuclear events (atmospheric thermonuclear tests: 1954 and 1962-63; Chernobyl accident: 1986) allow an absolute dating of corresponding layers. These determinations need radiochemical separations (electro-plating, ion exchange filters), followed by ultra low level alpha and gamma spectrometries, or beta counting (137Cs, 90Sr). The high purity - N type - germanium detector (Compton-suppressed) allows the 210Pb analysis at 46.52 keV, enabling a direct comparison with 210Po alpha spectrometry. Typical applications concern primarily dating, and the determination of mean annual accumulation rates of glaciers, sedimentation rate and mixing time in lakes, with their associated spatio-temporal variations. These measurements give access to the global fallouts of radionuclides and to meteorological parameters: air to snow (or sediment) transfer, deposition processes and atmospheric circulation

172

Absolute calibration of the neutron yield measurement on JT-60 Upgrade  

International Nuclear Information System (INIS)

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain Q in DD operating tokamaks. Total neutron yield is measured with 235U and 238U fission chambers and 3He proportional counters in JT-60 Upgrade. The in situ calibration was performed by moving the 252Cf neutron source toroidally through the JT-60 vacuum vessel. Detection efficiencies of three 235U and two 3He detectors were measured for 92 locations of the neutron point source in toroidal scans at two different major radii. The total detection efficiency for the torus neutron source was obtained by averaging the point efficiencies over the whole toroidal angle. The uncertainty of the resulting absolute plasma neutron source calibration is estimated to be ± 10%. (author)

173

Determination of collagen fibril size via absolute measurements of second-harmonic generation signals  

Science.gov (United States)

The quantification of collagen fibril size is a major issue for the investigation of pathological disorders associated with structural defects of the extracellular matrix. Second-harmonic generation microscopy is a powerful technique to characterize the macromolecular organization of collagen in unstained biological tissues. Nevertheless, due to the complex coherent building of this nonlinear optical signal, it has never been used to measure fibril diameter so far. Here we report absolute measurements of second-harmonic signals from isolated fibrils down to 30?nm diameter, via implementation of correlative second-harmonic-electron microscopy. Moreover, using analytical and numerical calculations, we demonstrate that the high sensitivity of this technique originates from the parallel alignment of collagen triple helices within fibrils and the subsequent constructive interferences of second-harmonic radiations. Finally, we use these absolute measurements as a calibration for ex vivo quantification of fibril diameter in the Descemet’s membrane of a diabetic rat cornea.

Bancelin, Stéphane; Aimé, Carole; Gusachenko, Ivan; Kowalczuk, Laura; Latour, Gaël; Coradin, Thibaud; Schanne-Klein, Marie-Claire

2014-09-01

174

Absolute measurement of the nitrogen fluorescence yield in air between 300 and 430 nm  

CERN Document Server

The nitrogen fluorescence induced in air is used to detect ultra-high energy cosmic rays and to measure their energy. The precise knowledge of the absolute fluorescence yield is the key quantity to improve the accuracy on the cosmic ray energy. The total yield has been measured in dry air using a 90Sr source and a [300-430 nm] filter. The fluorescence yield in air is 4.23 $\\pm$ 0.20 photons per meter when normalized to 760 mmHg, 15 degrees C and with an electron energy of 0.85 MeV. This result is consistent with previous experiments made at various energies, but with an accuracy improved by a factor of about 3. For the first time, the absolute continuous spectrum of nitrogen excited by 90Sr electrons has also been measured with a spectrometer. Details of this experiment are given in one of the author's PhD thesis [32].

Lefeuvre, G; Gorodetzky, P; Patzak, T; Salin, P

2007-01-01

175

Absolute structure-factor measurements of an Al-Pd-Mn quasicrystal.  

Science.gov (United States)

A number of X-ray reflections from an icosahedral quasicrystal Al-Pd-Mn have been measured with great accuracy on an absolute basis by making use of Bragg-case diffraction. Since the specimen had high crystal quality, the dynamical theory was used for analyzing the results and to extract structure factors from measured integrated intensities. Good agreement was found between theory and experiment for strong reflections. Anomalous transmission was found to be strong in the 'good' regions of the quasicrystalline specimen and it was measured on an absolute basis, but the small residual strains present in the specimen prevented an accurate comparison between theory and experiment. A detailed discussion is presented on the parameters that mostly affect anomalous transmission in relationship to the adopted structural model. PMID:12089461

Zhang, Y; Colella, R; Kycia, S; Goldman, A I

2002-07-01

176

Bolus injections of measured amounts of radioactivity  

International Nuclear Information System (INIS)

Many time-based radionuclide techniques, such as glomerular filtration rate measurement (GFR), require prompt intravenous delivery of and accurately measured tracer bolus with minimal residual tracer retention at the injection site. The quality assurance aspects of two antecubital vein, quantitative injection techniques were investigated. A flush bolus technique using a tuberculin syringe piggybacked onto a 10-ml saline flush was compared to a single blood pressure cuff injection technique. Scintillation camera data for each technique were compared for bolus duration in the abdominal aorta and for residual activity at the injection site at 5 min. Bolus times were measured as the FWHM of the gamma variate fit to the abdominal aortic regional time-activity curves. Relatively little focal activity was seen in the antecubital injection site following the flush bolus: marked residual activity was seen following the blood pressure cuff injections. The injection site/arm background ratios averaged 1.3 for the flush bolus and 30.1 for the cuff technique. Although both methods allowed accurate in vitro determination of administered radioactivity, only the tuberculin syringe flush bolus technique was acceptable for time-based quantitation because of its superior in vivo characteristics

177

Quality control laboratories for measuring radioactivity  

International Nuclear Information System (INIS)

In those laboratories involved in the measurement of radioactivity it is considered that a good determination requires, among other issues, and adequate monitoring of equipment performance and reagents and tracers. In this paper some of the parameters, of equipment performance are described together with some of the problems associated with their control and outlining possible solutions. Later, routine determinations are considered. For it is taken into account that an adequate control of the goodness of the results requires checking the whole measurement system, from sample reception to results delivery. In addition, the pros and cons of carrying out the enlargement of the control system so as to include management and performance of the laboratory as a whole in order to obtain an accreditation as external acknowledgement of well doing are discussed. Finally, this kind of acknowledgement, accreditation, is compared with the other kind of external acknowledgement of well doing: certification, establishing the former as adequate way of controlling not only the measurement process but also the management system. (Author). 15 refs.

178

High-precision Absolute Distance Measurements over a Long Range Based on Two Optoelectronic Oscillators  

CERN Document Server

Absolute distance measurement (ADM) over a long range has been studied intensely over the last several decades, due to its important applications in large-scale manufacturing and outer space explorations [1-5]. Traditional absolute distance measurements utilize detection of time-of-flight information, detection of phase shift, or a combination of the two [6-17]. In this paper, we present a novel scheme for high-precision ADM over a long range based on frequency detection by using two optoelectronic oscillators (OEO) to convert distance information to frequency information. By taking advantage of accumulative magnification theory, the absolute error of the measured distance is magnified by about 2*10E5 times, which makes the precision of the measured distance significantly improved. In our experiments, the maximum error is 1.5 um at the emulated ~6 km distance, including the drift error of about 1 um in the air path due to the change in environmental conditions. In addition, the measurable distance using this ...

Yu, Jinlong; Miao, Wang; Zhu, Jigui; Sun, Bin; Wang, Wenrui; Hu, Hao

2012-01-01

179

High-precision gravity measurements using absolute and relative gravimeters at Mount Etna (Sicily, Italy  

Directory of Open Access Journals (Sweden)

Full Text Available Accurate detection of time gravity changes attributable to the dynamics of volcanoes requires high-precision gravity measurements. With the aim of improving the quality of data from the Mount Etna gravity network, we used both absolute and relative gravimeters in a hybrid method. In this report, some of the techniques for gravity surveys are reviewed, and the results related to each method are compared. We show how the total uncertainty estimated for the gravity measurements performed with this combined use of absolute and relative gravimeters is roughly comparable to that calculated when the measurements are acquired using only relative gravimeters (the traditional method. However, the data highlight how the hybrid approach improves the measurement capabilities for surveying the Mount Etna volcanic area. This approach enhances the accuracy of the data, and then of the four-dimensional surveying, which minimizes ambiguities inherent in the gravity measurements. As a case study, we refer to two gravity datasets acquired in 2005 and 2010 from the western part of the Etna volcano, which included five absolute and 13 relative stations of the Etna gravity network.

Ciro Del Negro

2011-12-01

180

Temperature-dependent Absolute Refractive Index Measurements of Synthetic Fused Silica  

Science.gov (United States)

Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from temperatures ranging from 30 to 310 K at wavelengths from 0.4 to 2.6 microns with an absolute uncertainty of plus or minus 1 x 10 (exp -5). Statistical variations in derived values of the thermo-optic coefficient (dn/dT) are at the plus or minus 2 x 10 (exp -8)/K level. Graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient are presented for selected wavelengths and temperatures along with estimates of uncertainty in index. Coefficients for temperature-dependent Sellmeier fits of measured refractive index are also presented to allow accurate interpolation of index to other wavelengths and temperatures. We compare our results to those from an independent investigation (which used an interferometric technique for measuring index changes as a function of temperature) whose samples were prepared from the same slugs of material from which our prisms were prepared in support of the Kepler mission. We also compare our results with sparse cryogenic index data from measurements of this material from the literature.

Leviton, Douglas B.; Frey, Bradley J.

2006-01-01

 
 
 
 
181

Perfusion measurements with radioactively labelled microspheres  

International Nuclear Information System (INIS)

The technique and the evaluation of the microsphere-method are comprehensively represented in theory and practice. Some changes and new concepts are discussed, besides the known foundations and techniques, that assure an essential methodic improvement resp. practical simplifications. Two new formulas are derived within the frame of the theoretical principles, by which the absolute flux of shorts can be calculated, i.e. on the one hand in the case of known and on the other hand in the case of unknown applied amount of indicator. The determination of the optimal indicator dose is defined and formulated mathematically with respect to the experimental conditions to be expected. The matrix method was designed for the analysis of complex gamma spectra. Hereby there is no selective error accumulation in the case of low energy radio nuclids contrary to the so far exclusively used stripping technique. The number of possible error quantities was reduced by one resp. two variables. The error of particular radio nuclid components is quantitatively computed as standard deviation by means of the theory of approximated systems of linear equations. The external measurement of distance was developed. This technique is less susceptible for errors as the aliquota i.e. whole body measurement technique. Additionally less measurement time is needed. A flexible computer program for a desk top computer was developped for the evaluation. The data from the gamma spectrometer are recorded on tipe and automatically read in by the computer. The manual input are limited to the weights of the organs and some control parameter. The output is made by a clearly arranged table by means of a lineprinter. (orig./MG)

182

Radioactivity measurements using storage phosphor technology  

Energy Technology Data Exchange (ETDEWEB)

We propose to apply a recently developed charged particle radiation imaging concept in bio-medical research for fast, cost-effective characterization of radionuclides in contaminated sites and environmental samples. This concept utilizes sensors with storage photostimulable phosphor (SPP) technology as radiation detectors. They exhibit high sensitivity for all types of radiation and the response is linear over a wide dynamic range (>10{sup 5}), essential for quantitative analysis. These new sensors have an Active area of up to 35 cm x 43 cm in size and a spatial resolution as fine as 50 {mu}m. They offer considerable promise as large area detectors for fast characterization of radionuclides with an added ability to locate and identify hot spots. Tests with SPP sensors have found that a single alpha particle effect can be observed and an alpha field of 100 dpm/100 cm{sup 2} or a beta activity of 0.1 dpm/mm{sup 2} or gamma radiation of few {mu}R/hr can all be measured in minutes. Radioactive isotopes can further be identified by energy discrimination which is accomplished by placing different thicknesses of filter material in front of the sensor plate. For areas with possible neutron contamination, the sensors can be coupled to a neutron to charged particle converter screen, such as dysprosium foil to detect neutrons. Our study has shown that this approach can detect a neutron flux of 1 n/cm{sup 2}s or lower, again with only minutes of exposure time. The utilization of these new sensors can significantly reduce the time and cost required for many site characterization and environmental monitoring tasks. The {open_quotes}exposure{close_quotes} time for mapping radioactivity in an environmental sample may be in terms of minutes and offer a positional resolution not obtainable with presently used counting equipment. The resultant digital image will lend itself to ready analysis.

Cheng, Y.T. [NeuTek, Darnestown, MD (United States); Hwang, J. [Advanced Technologies and Labs. International, Rockville, MD (United States); Hutchinson, M.R. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

1995-10-01

183

A system and methodologies for absolute QE measurements from the vacuum ultraviolet through the NIR  

CERN Document Server

In this paper we present our system design and methodology for making absolute quantum efficiency (QE) measurements through the vacuum ultraviolet (VUV) and verify the system with delta-doped silicon CCDs. Delta-doped detectors provide an excellent platform to validate measurements through the VUV due to their enhanced UV response. The requirements for measuring QE through the VUV are more strenuous than measurements in the near UV and necessitate, among other things, the use of a vacuum monochromator, good dewar chamber vacuum to prevent on-chip condensation, and more stringent handling requirements.

Jacquot, Blake C; Hoenk, Michael E; Greer, Frank; Jones, Todd J; Nikzad, Shouleh

2011-01-01

184

Temperature-dependent absolute refractive index measurements of synthetic fused silica  

CERN Document Server

Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center, we have measured the absolute refractive index of five specimens taken from a very large boule of Corning 7980 fused silica from temperatures ranging from 30 to 310 K at wavelengths from 0.4 to 2.6 microns with an absolute uncertainty of +/-1 x 10^-5. Statistical variations in derived values of the thermo-optic coefficient (dn/dT) are at the +/-2 x 10^-8/K level. Graphical and tabulated data for absolute refractive index, dispersion, and thermo-optic coefficient are presented for selected wavelengths and temperatures along with estimates of uncertainty in index. Coefficients for temperature-dependent Sellmeier fits of measured refractive index are also presented to allow accurate interpolation of index to other wavelengths and temperatures. We compare our results to those from an independent investigation (which used an interferometric technique for measuring index changes as a function of temperatur...

Leviton, Douglas B

2008-01-01

185

Methods of measuring radioactivity in the environment  

International Nuclear Information System (INIS)

A variety of sampling methods have been utilized to assess the amount of deposited activity, mainly from 137Cs, from the Chernobyl accident and from nuclear weapons tests. Starting with the Chernobyl accident in 1986 sampling of air and rain was used to determine the composition and amount of radioactive debris from this accident. The resulting deposition and its removal from urban areas was then studied through measurements on sewage sludge and water. The main part of the thesis considers methods of determining the amount of radiocesium in the ground through soil sampling. In connection with soil sampling a method of optimizing the sampling procedure has been developed and tested in the areas of Sweden with high amounts of 137Cs from the Chernobyl accident. This method was then used in a survey of the activity in soil in Scania (south Sweden) with fallout activity from nuclear weapons and Chernobyl. By comparing the results from this survey with deposition calculated from precipitation measurements it was found possible to predict the deposition pattern over Scania for both nuclear weapons and Chernobyl fallout. In addition, the vertical distribution of 137Cs has been modelled and the temporal variation of the depth distribution has been described. 65 refs

186

Hyperspectral interferometry for single-shot absolute measurement of two-dimensional optical path distributions  

International Nuclear Information System (INIS)

We propose a method that we call hyperspectral interferometry (HSI) to resolve the 2? phase unwrapping problem in the analysis of interferograms recorded with a narrow-band light source. By using a broadband light source and a hyperspectral imaging system, a set of interferograms at different wave numbers are recorded simultaneously on a high resolution image sensor. These are then assembled to form a three-dimensional intensity distribution. By Fourier transformation along the wave number axis, an absolute optical path difference is obtained for each pixel independently of the other pixels in the field of view. As a result, interferograms with spatially distinct regions are analysed as easily as continuous ones. The approach is illustrated with a HSI system to measure 3D profiles of optically smooth or rough surfaces. Compared to existing profilometers able to measure absolute path differences, the single-shot nature of the approach provides greater immunity from environmental disturbance

187

The absolute free-volume fraction in polymers from positron lifetime measurements  

International Nuclear Information System (INIS)

The summary of annihilation experiments of 6 simple elastomers in wide temperature interval of (15 - 370) K is presented. It is shown that combined use of positron annihilation lifetime spectroscopy (PAL) and dilatometry (specific volume measurement) provides the temperature dependence of absolute value of fraction of free volume f (T) and a unique information on thermal expansion coefficient of occupied volume ?0. The proposed model allows the determination of absolute value of occupied volume V0. In the case of poly(isobutylene) and cis-trans 1,4 poly(butadiene) results from PAL are compared with that obtained from the viscosity and the temperature shift parameter measurements. This comparison indicates that the positron annihilation reflects the same basic mechanism as the viscosity and relaxation processes. (orig.)

188

Hyperspectral interferometry for single-shot absolute measurement of 3-D shape and displacement fields  

Directory of Open Access Journals (Sweden)

Full Text Available We propose a method that we call Hyperspectral Interferometry (HSI to resolve the 2? phase unwrapping problem in the analysis of interferograms recorded with a narrow-band light source. By using a broad-band light source and hyperspectral imaging system, a set of interferograms at different wavenumbers are recorded simultaneously on a high resolution image sensor. These are then assembled to form a three-dimensional intensity distribution. By Fourier transformation along the wavenumber axis, an absolute optical path difference is obtained for each pixel independently of the other pixels in the field of view. As a result, interferograms with spatially distinct regions are analysed as easily as continuous ones. The approach is illustrated with a HSI system to measure 3-D profiles of optically smooth or rough surfaces. Compared to existing profilometers able to measure absolute path differences, the single shot nature of the approach provides greater immunity from environmental disturbance.

Ruiz P. D.

2010-06-01

189

Precise Measurement of the Absolute Yield of Fluorescence Photons in Atmospheric Gases  

Energy Technology Data Exchange (ETDEWEB)

We have performed a measurement of the absolute yield of fluorescence photons at the Fermilab Test Beam. A systematic uncertainty at 5% level was achieved by the use of Cherenkov radiation as a reference calibration light source. A cross-check was performed by an independent calibration using a laser light source. A significant improvement on the energy scale uncertainty of Ultra-High Energy Cosmic Rays is expected.

Ave, M.; /Karlsruhe, Inst. Technol.; Bohacova, M.; /Chicago U., EFI; Daumiller, K.; /Karlsruhe, Inst. Technol.; Di Carlo, P.; /INFN, Aquila; Di Giulio, C.; /INFN, Rome; Luis, P.Facal San; /Chicago U., EFI; Gonzales, D.; /Karlsruhe U., EKP; Hojvat, C.; /Fermilab; Horandel, J.R.; /Nijmegen U., IMAPP; Hrabovsky, M.; /Palacky U.; Iarlori, M.; /INFN, Aquila /Karlsruhe, Inst. Technol.

2011-01-01

190

Measurement of the absolute branching fractions for Do decays into K-?+,K-?+?+?-, anti Kanti o?+?-  

International Nuclear Information System (INIS)

Using the ARGUS detector at the e+e- storage ring DORIS II we have measured the absolute branching ratios of the D-o meson, Br(D0?K-?+)=(3.41±0.12±0.28)%, Br(D0?K-?+?+?-)=(6.80±0.27±0.57)%, and Br(D0? anti K0?+?-)=(5.03±0.39±0.49)%. (orig.)

191

FFTF (FAST FLUX TEST FACILITY) REACTOR CHARACTERIZATION PROGRAM ABSOLUTE FISSION RATE MEASUREMENTS  

Energy Technology Data Exchange (ETDEWEB)

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

FULLER JL; GILLIAM DM; GRUNDL JA; RAWLINS JA; DAUGHTRY JW

1981-05-01

192

Absolute measurement of a standard thermal-neutron flux using gold-detector activation  

International Nuclear Information System (INIS)

The density of neutrons in a standard stacking is determined between the zero-energy and the cut-off energy of 1 mm thick cadmium unit using a gold detector. Its absolute activity is measured using a 4 ? ? counter calibrated for 4 ? ?,? coincidence by counting strongly active sources. The correction factor F due to the disintegration process for the gold is determined experimentally. ?0 = N0ECdV0 = 6495 ± 1.5 per cent n/cm2/s. (author)

193

Absolute Frequency Measurement of Rubidium 5S-7S Two-Photon Transitions  

CERN Document Server

We report the absolute frequency measurements of rubidium 5S-7S two-photon transitions with a cw laser digitally locked to an atomic transition and referenced to an optical frequency comb. The narrow, two-photon transition, 5S-7S (760 nm) insensitive to first order in a magnetic field, is a promising candidate for frequency reference. The performed tests yield the transition frequency with accuracy better than reported previously.

Morzynski, Piotr; Ablewski, Piotr; Gartman, Rafal; Gawlik, Wojciech; Maslowski, Piotr; Nagorny, Bartlomiej; Ozimek, Filip; Radzewicz, Czeslaw; Witkowski, Marcin; Ciurylo, Roman; Zawada, Michal

2013-01-01

194

Geometry of expanding absolutely continuous invariant measures and the liftability problem  

International Nuclear Information System (INIS)

We consider a quite broad class of maps on compact manifolds of arbitrary dimension possibly admitting critical points, discontinuities and singularities. Under some mild nondegeneracy assumptions we show that f admits an induced Gibbs-Markov map with integrable inducing times if and only if it has an ergodic invariant probability measure which is absolutely continuous with respect to the Riemannian volume and has all Lyapunov exponents positive. (author)

195

FFTF (Fast Flux Test Facility) Reactor Characterization Program: Absolute Fission-rate Measurements  

Energy Technology Data Exchange (ETDEWEB)

Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

Fuller, J.L.; Gilliam, D.M.; Grundl, J.A.; Rawlins, J.A.; Daughtry, J.W.

1981-05-01

196

A large-scale method to measure absolute protein phosphorylation stoichiometries  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The underlying functional role of protein phosphorylation is impacted by its fractional stoichiometry. Thus, a comprehensive strategy to study phosphorylation dynamics should include an assessment of site stoichiometry. Here, we developed an integrated method that relies on phosphatase treatment and stable isotope labeling to determine the absolute stoichiometries of protein phosphorylation on a large-scale. This approach requires the measurement of only a single ratio relating phosphatase- a...

Haas, Wilhelm; Dephoure, Noah; Huttlin, Edward L.; Zhai, Bo; Sowa, Mathew E.

2011-01-01

197

A new absolute reference for atmospheric longwave irradiance measurements with traceability to SI units  

Science.gov (United States)

Two independently designed and calibrated absolute radiometers measuring downwelling longwave irradiance were compared during two field campaigns in February and October 2013 at Physikalisch Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC). One absolute cavity pyrgeometer (ACP) developed by NREL and up to four Integrating Sphere Infrared Radiometers (IRIS) developed by PMOD/WRC took part in these intercomparisons. The internal consistency of the IRIS radiometers and the agreement with the ACP were within ±1 W m-2, providing traceability of atmospheric longwave irradiance to the international system of units with unprecedented accuracy. Measurements performed during the two field campaigns and over the past 4 years have shown that the World Infrared Standard Group (WISG) of pyrgeometers is underestimating clear-sky atmospheric longwave irradiance by 2 to 6 W m-2, depending on the amount of integrated water vapor (IWV). This behavior is an instrument-dependent feature and requires an individual sensitivity calibration of each pyrgeometer with respect to an absolute reference such as IRIS or ACP. For IWV larger than 10 mm, an average sensitivity correction of +6.5% should be applied to the WISG in order to be consistent with the longwave reference represented by the ACP and IRIS radiometers. A concerted effort at international level will need to be implemented in order to correct measurements of atmospheric downwelling longwave irradiance traceable to the WISG.

Gröbner, J.; Reda, I.; Wacker, S.; Nyeki, S.; Behrens, K.; Gorman, J.

2014-06-01

198

Absolute measurement of electron-cloud density in a positively charged particle beam.  

Science.gov (United States)

Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse. PMID:17026106

Kireeff Covo, Michel; Molvik, Arthur W; Friedman, Alex; Vay, Jean-Luc; Seidl, Peter A; Logan, Grant; Baca, David; Vujic, Jasmina L

2006-08-01

199

Steady Neutron Source Semi absolute Method for Measurements of Thermal Neutron Absorption in Small Samples  

International Nuclear Information System (INIS)

Full Text: A semi-absolute method for measurements of thermal neutron absorption cross-section in discrete samples of unknown material, using an isotopic neutron source, is put forward in this work. Other bulk's macro parameters: diffusion length and diffusion coefficient, can be equally obtained. There are three fundamental and necessary factors combined in this method: available experimental facilities, simplicity when measuring procedures are performed and it needed small quantities of material. Measurements on samples of light water poisoned with boric acid (150 c.c), placed deep in a graphite pile were performed. Theoretical models, system design and results have been benchmarked with a Monte Carlo simulation using MCNP Transport Code

200

LHCb: A novel method for an absolute luminosity measurement at LHCb using beam-gas imaging  

CERN Multimedia

A novel technique to measure the absolute luminosity at the Large Hadron Collider (LHC) using beam-gas interactions has been successfully used in the LHCb experiment. A gas injection device (SMOG) has been installed in the LHCb experiment to increase the pressure around the interaction point during dedicated fills. The Beam Gas Imaging method (BGI) has now the potential to surpass the accuracy of the commonly used van der Meer scan method (VDM). This poster presents the principles of the Beam Gas Imaging method used to measure the beam overlap integral. Furthermore the gas injection increased the accuracy measurement of the so-called ghost charges and also intensities per bunch.

Barschel, C

2013-01-01

 
 
 
 
201

METHODS FOR THE REALIZATION OF RADIOACTIVE STANDARDS AND FOR THE ENVIRONMENTAL RADIOACTIVITY MEASUREMENT  

Directory of Open Access Journals (Sweden)

Full Text Available The radionuclide metrology assures: the realization, the conservation and the transmission of the “activity” standards, in various fields of measurement, environmental radioactivity characterization being included. The Radionuclide Metrology Laboratory (RML, IFIN-HH, usually prepares radioactivity standards (reference materials, consisting from: standard solutions, point and large area alpha and beta standard sources, and gamma volume standard sources used for the measurement of environmental samples and for the calibration of surface contamination monitors.The most important measurement methods used in the environmental radioactivity measurements, developed in IFIN-HH, are: gross alpha and gross beta measurements and gamma-ray spectrometry measurements. The choice of the adequate method depends on several factors, such as: type of emitted radiation, existence of a single or mixture of radionuclides, physical shape of the matrix.The authors describe the methods for the realization of standard sources used for the calibration of equipment used in such monitoring and methods for the environmental radioactivity measurement.

ANDREI ANTOHE

2011-06-01

202

Absolute cerebral blood volume and blood flow measurements based on synchrotron radiation quantitative computed tomography.  

Science.gov (United States)

Synchrotron radiation computed tomography opens new fields by using monochromatic x-ray beams. This technique allows one to measure in vivo absolute contrast-agent concentrations with high accuracy and precision, and absolute cerebral blood volume or flow can be derived from these measurements using tracer kinetic methods. The authors injected an intravenous bolus of an iodinated contrast agent in healthy rats, and acquired computed tomography images to follow the temporal evolution of the contrast material in the blood circulation. The first image acquired before iodine infusion was subtracted from the others to obtain computed tomography slices expressed in absolute iodine concentrations. Cerebral blood volume and cerebral blood flow maps were obtained after correction for partial volume effects. Mean cerebral blood volume and flow values (n = 7) were 2.1 +/- 0.38 mL/100 g and 129 +/- 18 mL. 100 g-1. min-1 in the parietal cortex; and 1.92 +/- 0.32 mL/100 g and 125 +/- 17 mL. 100 g-1. min-1 in the caudate putamen, respectively. Synchrotron radiation computed tomography has the potential to assess these two brain-perfusion parameters. PMID:12679727

Adam, Jean-François; Elleaume, Hélène; Le Duc, Géraldine; Corde, Stéphanie; Charvet, Anne-Marie; Troprès, Irène; Le Bas, Jean-François; Estève, François

2003-04-01

203

Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source.  

Science.gov (United States)

This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by using an absolute detector temporarily placed at the downstream end of the instrument. This provides an estimation of the reflectivity of all x-ray optical elements in the beamline and provides the absolute photon number per bandwidth per pulse. This parameter is important for many experiments that need to understand the trade-offs between high energy resolution and high flux, such as experiments focused on studying materials via resonant processes. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content. PMID:25321502

Tiedtke, K; Sorokin, A A; Jastrow, U; Jurani?, P; Kreis, S; Gerken, N; Richter, M; Arp, U; Feng, Y; Nordlund, D; Soufli, R; Fernández-Perea, M; Juha, L; Heimann, P; Nagler, B; Lee, H J; Mack, S; Cammarata, M; Krupin, O; Messerschmidt, M; Holmes, M; Rowen, M; Schlotter, W; Moeller, S; Turner, J J

2014-09-01

204

Scanning Laser Polarimetry for Measurement of Retinal Nerve Fiber Layer in Absolute, Advanced and Early Glaucoma  

Directory of Open Access Journals (Sweden)

Full Text Available Background: To detect differences in retinal nerve fiber layer (RNFL measurements inabsolute, advanced and early glaucoma with scanning laser polarimetry (TheNerve Fiber Analyzer GDx, and to assess the usefulness and limitations ofthis technique for longitudinal follow-up of glaucoma patients.Methods: This is a prospective, cross-sectional study. Twenty-one eyes of 21 patientswith absolute glaucoma, twenty-six eyes of 26 patients with advanced glaucomaand twenty-four eyes of 24 patients with early glaucoma were imagedusing scanning laser polarimetry. The twelve standard GDx measurementparameters were compared using ANOVA (analysis of variance and theTukey test.Results: No significant differences were demonstrated for any of the twelve GDxmeasurement parameters between absolute and advanced glaucoma cases.There were significant differences for some GDx parameters, including theGDx number (p < 0.0001 superior ratio (p < 0.0001, inferior ratio (p <0.0001, superior/nasal ratio (p < 0.0001, maximum modulation (p <0.0001, ellipse modulation (p < 0.0001 and inferior average (p = 0.001between early and advanced glaucoma, and, between early and absoluteglaucoma. Significant differences were demonstrated for the superior average(p = 0.01 parameter between early and absolute glaucoma, but notbetween early and advanced glaucoma.Conclusions: For follow-up of glaucoma progression, RNFL measurements using scanninglaser polarimetry are more useful in the early stage than in the advancedstage.

Jen-Chia Tsai

2006-04-01

205

Absolute efficiency measurement for neutron detectors using Cf-252 neutron source  

International Nuclear Information System (INIS)

Absolute efficiency values for 5'' diameter x 2'' thick. BC-501 liquid scintillation detector at neutron energies ranging from 1 to 14 MeV were measured. Time-of-flight technique was employed to determine the energies of neutrons emitted from spontaneous fission of Cf-252 located inside a fission chamber. Time-of-flight spectra were acquired at neutron energy threshold of 1 MeV using the Multiparameter-Buffer System controlled by the micro VAX 11 computer. Experimental neutron energy spectra was compared to the theoretical Maxwellian distributed spectrum to determine the ratio of detected neutrons by detector and actual emitted neutrons from Cf-252 source. The actual emitted neutrons were measured by means of the fission chamber detector. This ratio of numbers of neutrons relates directly to the absolute efficiency value of the detector at each neutron-energy range. The absolute efficiency values for 5'' diameter x 2 diameter thick detector are varied from 5% to 30% depending on the neutron energy range and neutron energy threshold. Experimental uncertainties are less than 1% for neutron-energy ranging from 1 to 10 MeV but increased to 5% above 10 MeV

206

Flowrate measurements in closed pipes by the method of transit time measurement. Pt.1 Method of transit time of a radioactive tracer  

International Nuclear Information System (INIS)

Classical methods of flowrate measuring in closed pipes generally make use of indirect principles (for example: the measurements of the pressure loss through an orifice plate). Absolute or fundamental methods of the measurements of volume and time allow the ''in situ'' calibration and control of flowmeters in their nominal conditions of use. The method of transit-time measurements by fast injection of a radioactive tracer is described and analyzed

207

Radioactivity  

International Nuclear Information System (INIS)

This pedagogical document presents the origin, effects and uses of radioactivity: where does radioactivity comes from, effects on the body, measurement, protection against radiations, uses in the medical field, in the electric power industry, in the food (ionization, radio-mutagenesis, irradiations) and other industries (radiography, gauges, detectors, irradiations, tracers), and in research activities (dating, preservation of cultural objects). The document ends with some examples of irradiation levels (examples of natural radioactivity, distribution of the various sources of exposure in France). (J.S.)

208

Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram  

Science.gov (United States)

The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

2014-10-01

209

Radioactivity concentration measuring device for radiation waste containing vessel  

International Nuclear Information System (INIS)

The device of the present invention can precisely and accurately measure a radioactive concentration of radioactive wastes irrespective of the radioactivity concentration distribution. Namely, a Ge detector having a collimator and a plurality of radiation detectors are placed at the outside of the radioactive waste containing vessel in such a way that it can rotate and move vertically relative to the vessel. The plurality of radiation detectors detect radiation coefficient signals at an assumed segment unit of a predetermined length in vertical direction and for every predetermined angle unit in the rotational direction. A weight measuring device determines the weight of the vessel. A computer calculates an average density of radioactivity for the region filled with radioactivity based on the determined net weight and radiation coefficient signals assuming that the volume of the radioactivity is constant. In addition, the computer calculates the amount of radioactivity in the assumed segment by conducting ? -ray absorption compensation calculation for the material in the vessel. Each of the amount of radioactivity is integrated to determine the amount of radioactivity in the vessel. (I.S.)

210

International conventions for measuring radioactivity of building materials  

International Nuclear Information System (INIS)

In buildings, whether civil or industrial, natural radioactivity always occurs at different degrees in the materials (main building materials, decorative materials). Concerns on radioactivity from building materials is unavoidable for human living and developing. As a member of WTO, China's measuring method of radioactivity for building materials, including radionuclides limitation for building materials, hazard evaluation system etc, should keep accordance with the international rules and conventions. (author)

211

Absolute photoionization cross-section measurements of the Kr I isoelectronic sequence  

Science.gov (United States)

Photoionization spectra have been recorded in the 4s , 4p , and 3d resonance regions for the Kr I isoelectronic sequence using both the dual laser produced plasma (DLP) technique (at DCU) to produce photoabsorption spectra, and the merged ion beam and synchrotron radiation technique (at ASTRID) to measure absolute photoionization cross sections. Profile parameters are compared for the 4s-np resonances of Rb+ and Sr2+ . Many 4p?ns , md transitions are identified with the aid of Hartree-Fock calculations, and consistent quantum defects are observed for the various ns and md Rydberg series. Absolute single and double photoionization cross sections recorded in the 3d region for Rb+ and Sr2+ ions show preferential decay via double photoionization. This is only the second report to our knowledge where both the DLP technique and the merged-beam technique have been used simultaneously to record photoionization spectra, and the advantages of both techniques (i.e., better resolution in the case of DLP and values for absolute photoionization cross sections in the case of the merged-beam technique) are highlighted.

Kilbane, D.; Folkmann, F.; Bizau, J.-M.; Banahan, C.; Scully, S.; Kjeldsen, H.; van Kampen, P.; Mansfield, M. W. D.; Costello, J. T.; West, J. B.

2007-03-01

212

Absolute Position of Targets Measured Through a Chamber Window Using Lidar Metrology Systems  

Science.gov (United States)

Lidar is a useful tool for taking metrology measurements without the need for physical contact with the parts under test. Lidar instruments are aimed at a target using azimuth and elevation stages, then focus a beam of coherent, frequency modulated laser energy onto the target, such as the surface of a mechanical structure. Energy from the reflected beam is mixed with an optical reference signal that travels in a fiber path internal to the instrument, and the range to the target is calculated based on the difference in the frequency of the returned and reference signals. In cases when the parts are in extreme environments, additional steps need to be taken to separate the operator and lidar from that environment. A model has been developed that accurately reduces the lidar data to an absolute position and accounts for the three media in the testbed air, fused silica, and vacuum but the approach can be adapted for any environment or material. The accuracy of laser metrology measurements depends upon knowing the parameters of the media through which the measurement beam travels. Under normal conditions, this means knowledge of the temperature, pressure, and humidity of the air in the measurement volume. In the past, chamber windows have been used to separate the measuring device from the extreme environment within the chamber and still permit optical measurement, but, so far, only relative changes have been diagnosed. The ability to make accurate measurements through a window presents a challenge as there are a number of factors to consider. In the case of the lidar, the window will increase the time-of-flight of the laser beam causing a ranging error, and refract the direction of the beam causing angular positioning errors. In addition, differences in pressure, temperature, and humidity on each side of the window will cause slight atmospheric index changes and induce deformation and a refractive index gradient within the window. Also, since the window is a dispersive media, the effect of both phase and group indices have to be considered. Taking all these factors into account, a method was developed to measure targets through multiple regions of different materials and produce results that are absolute measurements of target position in three-dimensional space, rather than simply relative position. The environment in which the lidar measurements are taken must be broken down into separate regions of interest and each region solved for separately. In this case, there were three regions of interest: air, fused silica, and vacuum. The angular position of the target inside the chamber is solved using only phase index and phase velocity, while the ranging effects due to travel from air to glass to vacuum/air are solved with group index and group velocity. When all parameters are solved simultaneously, an absolute knowledge of the position of each target within an environmental chamber can be derived. Novel features of this innovation include measuring absolute position of targets through multiple dispersive and non-dispersive media, deconstruction of lidar raw data from a commercial off-the-shelf unit into reworkable parameters, and use of group velocities to reduce range data. Measurement of structures within a vacuum chamber or other harsh environment, such as a furnace, may now be measured as easily as if they were in an ambient laboratory. This analysis permits transformation of the raw data into absolute spatial units (e.g., mm). This technique has also been extended to laser tracker, theodolite, and cathetometer measurements through refractive media.

Kubalak, David; Hadjimichael, Theodore; Ohl, Raymond; Slotwinski, Anthony; Telfer, Randal; Hayden, Joseph

2012-01-01

213

A flowrate measurement method by counting of radioactive particles suspended in a liquid  

International Nuclear Information System (INIS)

By external counting of fine #betta# emitting radioactive particles suspended in a liquid, the flowrate in a system of pipes can be measured. The study comprises three phases: 1. - The hydraulic validity of the method is demonstrated in laminar as well as in turbulent flow under certain conditions of particles size and density and of liquid viscosity. 2. - Radioactive labelling of microspheres of serumalbumin or ion exchange resins with indium 113m delivered by a generator Tin 113 ? Indium 113m. 3. - Counting with a scintillation detector: a method of threshold overstepping is experimented with a mechanical or electronic simulator; the statistical study of particle superposition under the detector enables a correction for the resulting counting losses to be proposed. The method provides absolute measurements, but is particularly suitable to measure relative flowrates in a hydraulic network. It can be continuous and does not perturb the flow and the network. The accuracy of the method is analysed in details

214

Progress towards absolute intensity measurements of emissions from high temperature thermographic phosphors  

International Nuclear Information System (INIS)

Phosphor thermometry has been successfully used in a number of applications ranging from turbo-machinery, pyrolysis, supersonic and hypersonic studies in the past few decades. There are a number of issues related to high temperature, which include faster decays, decreasing emission intensity and increasing blackbody radiation. Although absolute lifetime decay values are readily available, there has been no known work presenting absolute intensity measurements throughout the phosphors operating temperature range. This additional information could help design engineers facilitate phosphor and instrument selection, optimise system setup, and help estimate the performance of the technique at higher temperatures, for any given optical setup. A number of well known high temperature thermographic phosphors were investigated including YAG:Tm, YAG:Tb and Y2O3:Eu from 20 oC in an excess of 1000 oC. Both 355 and 266 nm excitation wavelengths from a Q-switched Nd:YAG laser were used. The subsequent emissions were passed through a narrowband interference filter to isolate the peak emission wavelengths, and were collected using PMT. The methodology for an absolute measurement, which requires a sound understanding of the PMT, including solid angle, collection efficiency, dynode gain, calibration and electronic temporal response for intensity measurements is presented and discussed. The results clearly indicate a variation in phosphor intensity with an increasing temperature, which is considerably different amongst different phosphors under different excitation wavelengths. The combined standard uncertainty of measurement was estimated to be approximately ±10.7%. The existing system was able to monitor intensity values up to 900 oC for Mg3F2GeO4:Mn phosphors, 1100 oC for Y2O3:Eu, 1150 oC for YAG:Tb and up to 1400 oC for YAG:Tm thermographic phosphors. Y2O3:Eu using 266 nm excitation was found to exhibit the highest peak intensity per mJ of laser excitation from all the phosphors investigated at 20 oC. However, at high temperatures (900 oC+) YAG:Tm using 355 nm excitation was found to exhibit the highest peak intensity per mJ of an excitation energy. - Research highlights: ? A number of high temperature thermographic phosphors were investigated. ? Absolute measurement technique is used. ? Variation in intensity with increasing temperature of different phosphors is shown. ? Detected emissive power varied proportionally with the detectors collection area. ? Detected emissive power varied inversely proportional to the distance squared.

215

Progress towards absolute intensity measurements of emissions from high temperature thermographic phosphors  

Energy Technology Data Exchange (ETDEWEB)

Phosphor thermometry has been successfully used in a number of applications ranging from turbo-machinery, pyrolysis, supersonic and hypersonic studies in the past few decades. There are a number of issues related to high temperature, which include faster decays, decreasing emission intensity and increasing blackbody radiation. Although absolute lifetime decay values are readily available, there has been no known work presenting absolute intensity measurements throughout the phosphors operating temperature range. This additional information could help design engineers facilitate phosphor and instrument selection, optimise system setup, and help estimate the performance of the technique at higher temperatures, for any given optical setup. A number of well known high temperature thermographic phosphors were investigated including YAG:Tm, YAG:Tb and Y{sub 2}O{sub 3}:Eu from 20 {sup o}C in an excess of 1000 {sup o}C. Both 355 and 266 nm excitation wavelengths from a Q-switched Nd:YAG laser were used. The subsequent emissions were passed through a narrowband interference filter to isolate the peak emission wavelengths, and were collected using PMT. The methodology for an absolute measurement, which requires a sound understanding of the PMT, including solid angle, collection efficiency, dynode gain, calibration and electronic temporal response for intensity measurements is presented and discussed. The results clearly indicate a variation in phosphor intensity with an increasing temperature, which is considerably different amongst different phosphors under different excitation wavelengths. The combined standard uncertainty of measurement was estimated to be approximately {+-}10.7%. The existing system was able to monitor intensity values up to 900 {sup o}C for Mg{sub 3}F{sub 2}GeO{sub 4}:Mn phosphors, 1100 {sup o}C for Y2O3:Eu, 1150 {sup o}C for YAG:Tb and up to 1400 {sup o}C for YAG:Tm thermographic phosphors. Y{sub 2}O{sub 3}:Eu using 266 nm excitation was found to exhibit the highest peak intensity per mJ of laser excitation from all the phosphors investigated at 20 {sup o}C. However, at high temperatures (900 {sup o}C+) YAG:Tm using 355 nm excitation was found to exhibit the highest peak intensity per mJ of an excitation energy. - Research highlights: {yields} A number of high temperature thermographic phosphors were investigated. {yields} Absolute measurement technique is used. {yields} Variation in intensity with increasing temperature of different phosphors is shown. {yields} Detected emissive power varied proportionally with the detectors collection area. {yields} Detected emissive power varied inversely proportional to the distance squared.

Khalid, A.H. [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester, M60 1QD (United Kingdom); Kontis, K., E-mail: k.kontis@manchester.ac.u [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester, M60 1QD (United Kingdom)

2011-07-15

216

Absolute radiant power measurement of the X-ray free-electron laser at SACLA  

Science.gov (United States)

The Japanese hard X-ray free-electron laser (XFEL), SACLA (SPring-8 Angstrom Compact free-electron LAser), reached laser amplification at 10 keV photon energy in June 2011. SACLA can provide XFELs with its wavelength of shorter than 0.1 nm. Since the radiant power is a fundamental parameter of the XFEL beam which strongly influences nonlinear effects, its measurement in absolute terms is of significant importance. In the present study, the absolute radiant power of the XFEL was measured using a cryogenic radiometer at the BL3 in SACLA. The radiant power as a function of a silicon attenuator thickness was also measured to estimate the contribution of the higher harmonics. The radiant power in the range between 8 ?W and 1005 ?W was measured in the photon energies of 4.4 keV, 5.8 keV, 9.6 keV, 13.6 keV and 16.8 keV. The contribution of the higher harmonics is negligible except for the photon energy of 4.4 keV. The third harmonics component in the photon energy of 4.4 keV is about 1 %.

Tanaka, Takahiro; Kato, Masahiro; Kurosawa, Tadahiro; Saito, Norio; Kudo, Togo; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya

2013-03-01

217

Absolute fission rate measurement of 238U induced by 14 MeV neutrons penetrated composite material  

International Nuclear Information System (INIS)

In order to prove the model calculation method and parameter, the 238U absolute fission rate in the case of 14 MeV neutrons penetrating through the special composite material was measured by minitype slab uranium fission chambers. The measuring spots are distributed in the surface of iron ball hull along the different position of equator. The calculated results are compared with the experiment results. The total error of measured 238U absolute fission rate is 6.1%. (author)

218

Device for measuring liquid sodium absolute and differential pressures in the fast nuclear reactor coolant circuit  

International Nuclear Information System (INIS)

A system with a vessel forming part of the circuit is proposed for measuring the absolute and the differential liquid sodium pressures in the fast reactor coolant circuit. The space above the sodium level in the vessel is filled with an inert argon atmosphere. Mounted onto one vessel wall below the sodium level is a metal diaphragm closing one end of a tube filled with silicon oil. The other end of the tube is closed with a second metal diaphragm connected to the manometer pick-up. (Z.M.)

219

Absolute Measurement of Hadronic Branching Fractions of the D_s^+ Meson  

CERN Document Server

The branching fractions of D_s meson decays serve to normalize many measurements of processes involving charm quarks. Using 298 /pb of e+ e- collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for eight D_s decays with a double tag technique. In particular we determine the branching fraction B(D_s -> K- K+ pi+) = (5.50 +- 0.23 +- 0.16)%, where the uncertainties are statistical and systematic respectively. We also provide partial branching fractions for kinematic subsets of the K- K+ pi+ decay mode.

Alexander, J; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Libby, J; Powell, A; Wilkinson, G; Ecklund, K M; Love, W; Savinov, V; López, A; Méndez, H; Ramírez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L

2008-01-01

220

Measurements of the Absolute Branching Fractions of B±?K±Xcc  

International Nuclear Information System (INIS)

We study the two-body decays of B± mesons to K± and a charmonium state Xcc in a sample of 210.5 fb-1 of data from the BABAR experiment. We perform measurements of absolute branching fractions B(B±?K±Xcc) using a missing mass technique, and report several new or improved results. In particular, the upper limit B(B±?K±X(3872))-4 at 90% C.L. and the inferred lower limit B(X(3872)?J/??+?-)>4.2% will help in understanding the nature of the recently discovered X(3872)

 
 
 
 
221

Measurement of the absolute and differential cross sections for 7Li(?, n0)6Li  

International Nuclear Information System (INIS)

We have measured the cross section of the photoneutron reaction channel 7Li+??6Li(g.s.)+n where the progeny nucleus is the ground state of 6Li. We obtained the absolute cross section at photon energies 10, 11, 12, 13, 15, 20, 25, 30, and 35 MeV and also the dependence of the cross section on polar angle for all but the highest photon energy. For the energies 10 to 15 MeV we were able to use linearly polarized photons to obtain the dependence of the cross section on the photon polarization.

222

Absolute beam flux measurement at NDCX-I using gold-melting calorimetry technique  

Energy Technology Data Exchange (ETDEWEB)

We report on an alternative way to measure the absolute beam flux at the NDCX-I, LBNL linear accelerator. Up to date, the beam flux is determined from the analysis of the beam-induced optical emission from a ceramic scintilator (Al-Si). The new approach is based on calorimetric technique, where energy flux is deduced from the melting dynamics of a gold foil. We estimate an average 260 kW/cm2 beam flux over 5 {micro}s, which is consistent with values provided by the other methods. Described technique can be applied to various ion species and energies.

Ni, P.A.; Bieniosek, F.M.; Lidia, S.M.; Welch, J.

2011-04-01

223

Recent improvements of ISOLTRAP Absolute mass measurements of exotic nuclides at $10^{-8}$ precision  

CERN Document Server

In the past three years, the sensitivity and the performance of the Penning trap mass spectrometer ISOLTRAP have been enhanced significantly. These improvements, which range from technical developments to systematic studies of the various factors contributing to the uncertainty of the final mass result, now allow mass measurements of short-lived radionuclides with half-lives of less than 100 ms and with a precision of better than 10^-8. Using a newly developed carbon cluster ion source, ISOLTRAP can perform absolute mass measurements relative to the microscopic mass standard ^12C. These developments are reviewed as pertaining to the extension of ISOLTRAP mass measurements to higher precision and shorter half-lives and to molecular mass measurements. PACS: 07.75.+h (Mass spectrometers and related techniques), 21.10.Dr (Binding energies and masses), 32.10.Bi (Atomic masses, mass spectra, abundances, and isotopes), 36.40.Wa (Charged clusters).

Kellerbauer, A G

2003-01-01

224

Measurement of absolute regional lung air volumes from near-field x-ray speckles.  

Science.gov (United States)

Propagation-based phase contrast x-ray (PBX) imaging yields high contrast images of the lung where airways that overlap in projection coherently scatter the x-rays, giving rise to a speckled intensity due to interference effects. Our previous works have shown that total and regional changes in lung air volumes can be accurately measured from two-dimensional (2D) absorption or phase contrast images when the subject is immersed in a water-filled container. In this paper we demonstrate how the phase contrast speckle patterns can be used to directly measure absolute regional lung air volumes from 2D PBX images without the need for a water-filled container. We justify this technique analytically and via simulation using the transport-of-intensity equation and calibrate the technique using our existing methods for measuring lung air volume. Finally, we show the full capabilities of this technique for measuring regional differences in lung aeration. PMID:24514306

Leong, Andrew F T; Paganin, David M; Hooper, Stuart B; Siew, Melissa L; Kitchen, Marcus J

2013-11-18

225

Absolute Position Measurement in a Gas Time Projection Chamber via Transverse Diffusion of Drift Charge  

CERN Document Server

Time Projection Chambers (TPCs) with charge readout via micro pattern gaseous detectors can provide detailed measurements of charge density distributions. We here report on measurements of alpha particle tracks, using a TPC where the drift charge is amplified with Gas Electron Multipliers and detected with a pixel ASIC. We find that by measuring the 3-D topology of drift charge and fitting for its transverse diffusion, we obtain the absolute position of tracks in the drift direction. For example, we obtain a precision of 1~cm for 1~cm-long alpha track segments. To our knowledge this is the first demonstration of such a measurement in a gas TPC. This technique has several attractive features: it does not require knowledge of the initial specific ionization, is robust against bias from diffuse charge below detection threshold, and is also robust against high charge densities that saturate the detector response.

Lewis, P M; Hedges, M T; Jaegle, I; Seong, I S; Thorpe, T N

2014-01-01

226

Absolute photodetachment cross section measurements of the O- and OH- anion  

International Nuclear Information System (INIS)

Absolute total photodetachment cross sections of O- and OH- anions stored in a multipole radio frequency trap have been measured using a novel laser depletion tomography method. For OH- the total cross sections of 8.5(1)stat(3)syst and 8.1(1)stat(7)systx10-18 cm2, measured at 662 and 632 nm, respectively, were found constant in the temperature range of 8-300 K. The O- cross sections 5.9(1)stat(2)syst and 6.3(1)stat(2)systx10-18 cm2 measured at 170 K at 662 and 532 nm, respectively, agree within error estimations with preceding experiments and increase the accuracy of the widely used calibration standard for relative photodetachment measurements of diverse atomic and molecular species.

227

Improved Measurement of Absolute Hadronic Branching Fractions of the Ds+ Meson  

CERN Document Server

The branching fractions of Ds meson decays serve to normalize many measurements of processes involving charm quarks. Using 586 pb^-1 of e+ e- collisions recorded at a center of mass energy of 4.17 GeV, we determine absolute branching fractions for 13 Ds decays in 16 reconstructed final states with a double tag technique. In particular we make a precise measurement of the branching fraction B(Ds -> K- K+ pi+) = (5.55 +- 0.14 +- 0.13)%, where the uncertainties are statistical and systematic respectively. We find a significantly reduced value of B(Ds -> pi+ pi0 eta') compared to the world average, and our results bring the inclusively and exclusively measured values of B(Ds -> eta' X)$ into agreement. We also search for CP-violating asymmetries in Ds decays and measure the cross-section of e+ e- -> Ds* Ds at Ecm = 4.17 GeV.

Onyisi, P U E; Cinabro, D; Smith, M J; Zhou, P; Naik, P; Rademacker, J; Edwards, K W; Briere, R A; Vogel, H; Rosner, J L; Alexander, J P; Cassel, D G; Das, S; Ehrlich, R; Gibbons, L; Gray, S W; Hartill, D L; Heltsley, B K; Kreinick, D L; Kuznetsov, V E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Sun, W M; Yelton, J; Rubin, P; Lowrey, N; Mehrabyan, S; Selen, M; Wiss, J; Libby, J; Kornicer, M; Mitchell, R E; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Hietala, J; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Xiao, T; Powell, A; Thomas, C; Wilkinson, G; Asner, D M; Tatishvili, G; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Napolitano, J; Ecklund, K M; Insler, J; Muramatsu, H; Pearson, L J; Thorndike, E H; Artuso, M; Blusk, S; Mountain, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M

2013-01-01

228

Publication of measured values of radioactivity in food  

International Nuclear Information System (INIS)

The radioactivity in food is recorded at 20 different measuring points in the Federal States, furthermore at one coordinating office of the Federal Government, and at a number of research institutes. Measurements are carried out permanently, particularly with regard to the relevant radionuclides such as Cesium 134 and Cesium 137. The measured values of the radioactive contamination in food are published by the Federal States for reasons of competence, and also by the Federal Government, in its summarizing reports ''Environmental radioactivity and radiation exposure.'' (orig./HSCH)

229

First measurements of the absolute neutron spectrum using the Magnetic Recoil Spectrometer (MRS) at OMEGA  

International Nuclear Information System (INIS)

A new type of neutron spectrometer, called a Magnetic Recoil Spectrometer (MRS), has been built and implemented at the OMEGA laser facility (T. R. Boehly. D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)) for absolute measurements of the neutron spectrum in the range 6 to 30 MeV, from which fuel areal density (?R), ion temperature (Ti) and yield (Yn) can be determined. The results from the first MRS measurements of the absolute neutron spectrum are presented. In addition, measuring ?R at the National Ignition Facility (NIF) (G.H. Miller, E.I. Moses and C.R. Wuest, Nucl. Fusion 44, S228 (2004)) will be essential for assessing implosion performance during all stages of development from surrogate implosions to cryogenic fizzles and ignited implosions. To accomplish this, we are also developing an MRS for the NIF. As much of the R and D and instrument optimization of the MRS at OMEGA is directly applicable to the MRS at the NIF, a description of the MRS design on the NIF is discussed as well

230

Absolute specific heat measurements of a microgram Pb crystal using ac nanocalorimetry  

International Nuclear Information System (INIS)

Heat capacity measurements using the ac steady state method are often considered difficult to provide absolute accuracy. By adjusting the working frequency to maintain a constant phase and using the phase information to obtain the heat capacity, we have found that it is possible to achieve good absolute accuracy. Here we present a thermodynamic study of a ? 2.6 ?g Pb superconducting crystal to demonstrate the newly opened capabilities. The sample is measured using a differential membrane-based calorimeter. The custom-made calorimetric cell is a pile of thin film Ti heater, insulation layer and Ge1?xAux thermometer fabricated in the center of two Si3N4 membranes. It has a background heat capacity c = 7.21 K has a width asymp 20 mK and displays no upturn in C. From the heat capacity jump at Tc and the extrapolated Sommerfeld term we find ?C/?Tc 2.68. The latent heat curve obtained from the zero field heat capacity measurement, and the deviations of the thermodynamic critical field from the empirical expression Hc = Hc (0) [1 ? (T/Tc)2] are discussed. Both analyses give results in good agreement with literature.

231

Measuring the absolute position of EELS ionisation edges in a TEM  

International Nuclear Information System (INIS)

Measurements of absolute positions of electron energy loss spectroscopy (EELS) core-loss edges in a transmission electron microscopy (TEM) are hampered by noticeable errors caused by instabilities of the primary energy of the incident electrons. These instabilities originate from a continuous drift and random ripple of the high tension and are unavoidable in the present generation of TEM and scanning TEM microscopes. However, more precise measurements are desired, for instance, to study the shift of the edge onset between atoms of different valency or chemical environment, the so-called chemical shift. A solution to this problem is presented by collecting a series of short low-loss acquisitions immediately followed by core-loss ones. To ensure a minimal time lapse between core-loss and low-loss acquisitions, all operations must be computer controlled. Accumulation of a number of acquisitions and their summation corrected for energy drift allows to cancel the energy instabilities and to relate the core-loss EELS spectra to the absolute energy scale. A practical algorithm is presented as well as the necessary calibrations for such a procedure. Also, examples of spectra collected using this principle and the resulting measured chemical shifts in several metal-oxides are presented

232

High-resolution measurement of absolute ?-decay widths in 16O  

International Nuclear Information System (INIS)

By using a large-acceptance position-sensitive silicon detector array in coincidence with the high-resolution Munich Q3D spectrograph, unambiguous measurements have been made of the absolute ?-particle decay widths from excited states in 16O* in the energy range 13.85 to 15.87 MeV. Carbon targets have been bombarded with 42-MeV 6Li beams to induce 612C(36Li, d)816O* reactions. The deuteron ejectiles were measured in the Q3D and the results gated by 4He+12C breakup products detected in the silicon array, the efficiency of which was modeled using Monte Carlo simulations. By comparing total population and breakup-gated spectra, the following absolute ?-decay widths have been measured with high resolution: ??0/?tot = 0.87±0.11 (13.980 MeV), 1.04±0.15 (14.302 MeV), 0.92±0.10 (14.399 MeV), 0.59±0.04 (14.815 MeV), 0.88±0.18 (15.785 MeV), and ??1/?tot=1.14±0.08 (14.660 MeV), 0.46±0.06 (14.815 MeV).

233

Calculator for Standard Deviation and Optimum Conditions in Radioactive Measurements  

International Nuclear Information System (INIS)

A calculating device is described, suited for fast orientation in the conditions of radioactive measurements. Its usage minimizes the time needed for calculating the statistical accuracy and minimum detectable activity. The typical problems which could be solved by using it are as follows: (a) Calculation of the statistical accuracy (percentage natural standard deviation) for any radioactive measurement. (b) Determination of the minimum detectable activity (in count rate) for a chosen probability limit of the net count rate of the order of 90%, 95% 99%. (c) Determination of the optimum statistical conditions of the measurement. (d) Choice of the most suitable detector. The disadvantages of the existing automatic detectors used for measurement of radioactive samples are discussed and the ways to avoid them are shown. A counting device designed to measure radioactive samples with programmed statistical accuracy is described. (author)

234

Results of radioactivity measurements on foodstuffs in Romania  

International Nuclear Information System (INIS)

There are presented the results of gamma-spectrometric measurements performed between 1986-1995 on: milk and dairy products; meat and meat products; fish; wheat flour; fresh fruits and vegetables. The foodstuffs are sampled from some representative areas like: Bucharest, Bechet (affected by Kozloduj NPP, Bulgaria), Cernavoda, middle of Transylvania, Neamt. The radioactivity measurements are performed by high-resolution ?-ray spectrometry. There are identified and analysed mainly 134Cs, 137Cs, 40K and, sometimes, other radionuclides. There are pointed out: the constancy of natural radionuclides amounts; the drastic increasing in radioactive concentration in May 1986; the seasonal variation of radioactivity in some food items; the time - exponential diminution of radioactivity in 1991-1995; and the maximum permitted levels of radioactive contamination of foodstuffs following a nuclear accident. (author)

235

Absolute calibration of in vivo measurement systems using magnetic resonance imaging and Monte Carlo computations  

International Nuclear Information System (INIS)

Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. This method uses magnetic resonance imaging (MRI) to determine the anatomical makeup of an individual. A new MRI technique is also employed that is capable of resolving the fat and water content of the human tissue. This anatomical and biochemical information is used to model a mathematical phantom. Monte Carlo methods are then used to simulate the transport of radiation throughout the phantom. By modeling the detection equipment of the in vivo measurement system into the code, calibration factors are generated that are specific to the individual. Furthermore, this method eliminates the need for surrogate human structures in the calibration process. A demonstration of the proposed method is being performed using a fat/water matrix. (author)

236

Absolute calibration of in vivo measurement systems using magnetic resonance imaging and Monte Carlo computations  

International Nuclear Information System (INIS)

Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. This method uses magnetic resonance imaging (MRI) to determine the anatomical makeup of an individual. A new MRI technique is also employed that is capable of resolving the fat and water content of the human tissue. This anatomical and biochemical information is used to model a mathematical phantom. Monte Carlo methods are then used to simulate the transport of radiation throughout the phantom. By modeling the detection equipment of the in vivo measurement system into the code, calibration factors are generated that are specific to the individual. Furthermore, this method eliminates the need for surrogate human structures in the calibration process. A demonstration of the proposed method is being performed using a fat/water matrix

237

An absolute 3D measurement method using a 2D pattern based on digital moire  

Science.gov (United States)

With a remarkable evolution in the development of digital cameras, non-contact 3D measurement using computer vision has been rapidly developing in the past few decades. Excellent and well-accepted techniques include digital moire and stereo vision. An obvious drawback of digital moire is that it is not applicable to the measurement of significant discontinuities, which is common in this area of research. And in the process of measurement, error propagation is inevitable, especially under the condition of missing points. The reason for this shortcoming lies in its relative coding scheme. For stereo vision, it is based on triangulation which leads to an absolute measurement. However, correspondence searching and resolution limitation of measurement of lacking features are two of the major unsolved problems of stereo vision systems. Inspired by these two well-developed techniques, an absolute measuring method based on structured light is developed in this research, requiring only a camera and a projector. The philosophy behind the coding scheme is a hybrid of relativity to the center and absoluteness, or independence on every single point. The mathematical model of the system is described and theorems that relate to the guidance of designing such a system are introduced. Two important factors determine the accuracy of the 3D measurement: correspondence matching and calibration of the camera and the projector' parameters. For the correspondence matching, an image processing method is developed. Image subtraction, edge detection, grid permutation and establishment of sub-coordinate-systems are included in the algorithm. Aiming at the discontinuity measurement, discontinuous borders are marked out first by using a Gabor filter first. Epipolar geometry is then utilized in the process of searching out each corresponding points accurately on the image plane. Sub-pixel accuracy for correspondence matching can be achieved in this way. The second factor that affects the accuracy of the measurement system is concerned with the calibration of the whole system. A convenient calibration method for structured light systems is developed in this research. This calibration method significantly simplifies the calibration procedures, and experimental results are presented for the verification of this calibration method. And experiments verify accuracy of the whole measurement system. And its advantages over digital moire and stereo vision are presented and verified by experiments. However, this calibration method for structured light system is applicable to the existing methods that are based on the least squares minimization effort. The assumptions made for the calibration system are not suitable to the nonlinear stereo vision system. Moreover, the 2D planar pattern used in existing calibration methods cannot provide 3D information in the 3D space. To move it among different views will inadvertently introduce additional mechanical errors. An iterative calibration method is developed in order to solve the existing problems in the state-of-the-art calibration methods for stereo vision systems. It is the first time that an iterative calibration method is developed to solve the calibration of a two-camera system's calibration with iterations in the 3D space. Derivations are described for this iterative calibration algorithm using feedback control theory. Furthermore, the calibration target is designed and manufactured under specifications defined by the task has been created for. Experiments show the developed iterative calibration method based on feedback control can achieve convergent parameters. With the calibrated parameters, 3D measurement of the calibration target verifies the correctness and accuracy of this iterative calibration method. Hence, the contributions of this work are significant. An absolute 3D measurement system based on a 2D pattern using digital moire has been developed. At the same time, a novel calibration method for such a system has also been proposed and verified in this work. For investigation of calibration method on

Liao, Jiarui

238

Measurement of the absolute wavefront curvature radius in a heterodyne interferometer  

CERN Document Server

We present an analytical derivation of the coupling parameter relating the angle between two interfering beams in a heterodyne interferometer to the differential phase-signals detected by a quadrant photo-diode. This technique, also referred to as Differential Wavefront Sensing (DWS), is commonly used in space-based gravitational wave detectors to determine the attitude of a test-mass in one of the interferometer arms from the quadrant diode signals. Successive approximations to the analytical expression are made to simplify the investigation of parameter dependencies. Motivated by our findings, we propose a new measurement method to accurately determine the absolute wave-front curvature of a single measurement beam. We also investigate the change in coupling parameter when the interferometer "test-mirror" is moved from its nominal position, an effect which mediates the coupling of mirror displacement noise into differential phase-measurements.

Hechenblaikner, Gerald

2010-01-01

239

Superharp - a wire scanner with absolute position readout for beam energy measurement at CEBAF  

International Nuclear Information System (INIS)

The CEBAF superharp is an upgraded beam wire scanner which provides absolute beam position readout using a shaft encoder. Superharps allow for high precision measurements of the beam's profile and position (?x similar 10 ?m). The Hall C endstation at CEBAF will use three pairs of superharps to perform beam energy measurements with 10-3 accuracy. The three pairs are installed at the beginning, the mid-point and the end of the Hall C arc beamline. Using superharps in conjunction with a dual sensor system: the direct current pick-up and the bremsstrahlung detectors, beam profile measurements can be obtained over a wide beam current range of 1 similar 200 ?A. (orig.)

240

Absolute measurement of activity of ¹??Au foils using the 4??-? coincidence counting method and corrections by the Monte Carlo simulation.  

Science.gov (United States)

The thermal neutron fluence rate is determined by the gold activation method. The absolute activity of the irradiated gold foil is measured by a 4??-? coincidence counter. Using this method, corrections for the detection of conversion electrons and gamma rays by a 4?? counter are very important to obtain accurate absolute activity. In this work, Monte Carlo simulations were performed to derive the correction factor K. The absolute measurement of (198)Au activity for 20-100 ?m thickness Au foils were performed to verify the calculating model of the 4??-? coincidence counting system. PMID:21406431

Nishiyama, Jun; Harano, Hideki; Matsumoto, Tetsuro; Sato, Yasushi; Uritani, Akira; Kudo, Katsuhisa

2012-01-01

 
 
 
 
241

Pile-up correction in the measurement of 60Co absolute activity using sum-peak method  

International Nuclear Information System (INIS)

New pile-up correction method using AMP shaping time condition is suggested for the absolute activity measurement of Co-60 using sum-peak method. HPGe detector was used for Co-60 ?-ray spectroscopy at various AMP shaping time conditions and source position. In the determination of absolute activity, the angular correlation was considered, and the pile-up was corrected by extrapolating the measured value at various AMP shaping time condition to AMP shaping time 0 sec. As a result the uncertainty of the absolute activity is less than 3.0% and the deviation to the true activity is less than 3.5%

242

Measurements of absolute delayed neutron yield and group constants in the fast fission of 235U and 237Np  

International Nuclear Information System (INIS)

The delayed neutron activity resulting from the fast induced fission of 235U and 237Np has been studied. The six-group decay constants, relative abundances, and absolute yield of delayed neutrons from fast fission of 235U and 237Np were measured using the Godiva IV fast assembly at the Los Alamos Critical Experiments Facility. The absolute yield measured for 235U was 0.0163 ± 0.0008 neutron/fission. This value compares very well with the well-established Keepin absolute yield of 0.0165 ± 0.0005. The absolute yield value measured for 237Np was 0.0126 ± 0.0007. The measured delayed neutron parameters for 235U are corroborated with period (e-folding time) versus reactivity calculations

243

Measurement of the reaction ^7Be(p,?)^8B with a solid radioactive target  

Science.gov (United States)

The reaction ^7Be(p,?)^8B is regarded as a key to the understanding of the solar neutrino spectrum and thus most probably to the understanding of new neutrino properties. This contribution describes an experiment measuring the absolute cross section of ^7Be(p,?)^8B with a solid radioactive target in the energy range between 350 keV and 2.6 MeV. The experiment was performed at the Dynamitron Tandem Laboratory of the Ruhr-Universitaet Bochum, Germany.

Greife, Uwe

2000-04-01

244

An alternative approach to wavelength modulation spectroscopy for absolute measurements of gas parameters in industrial processes  

Science.gov (United States)

Wavelength modulation spectroscopy (WMS) with tunable diode lasers (TDLs) is the preferred technique for gas composition measurement in a growing number of industrial process control applications. Those systems using optical fiber cables or networks to address single or multiple sensing points are of particular interest. However, the conventional approaches suffer from a number of calibration / scaling factor issues which, although addressable, lead to added cost and accumulated errors in the final determination of gas concentration. Such issues are particularly problematic in industrial applications where the pressure may be varying and unknown. The target signal in WMS is an amplitude modulation (AM) component generated by the interaction of frequency modulation (FM) on the laser output with a rotational / vibrational gas absorption line function. However, direct laser amplitude modulation is also present and distorts the recovered target signals again leading to errors. Here we report an alternative approach in which we exploit the phase difference between the laser AM and the FM to provide direct recovery of the absolute gas absorption line function from which both the gas concentration and the pressure may be obtained from the depth and line width respectively. The method is absolute with no need for calibration thus eliminating the difficulties with the conventional approach. In our presentation, we report the basic principles of the technique and its experimental validation through a number of methane gas concentration and pressure measurements.

Johnstone, Walter; Duffin, Kevin; McGettrick, Andrew; Stewart, George

2007-09-01

245

The French National Network for the Measurement of Environmental Radioactivity  

International Nuclear Information System (INIS)

After Chernobyl accident in 1986, the government began to implement mechanisms to ensure the quality of measurements of environmental radioactivity and to assure the transparency of information on environmental radioactivity monitoring results. Within this context, the French National Network for the Measurement of Environmental Radioactivity (RNM), is created in 2002 under the Public Health Code. This network is developed under the auspices of ASN in collaboration with IRSN and in partnership with government departments, major nuclear licensees, health agencies and environmental protection associations. In order to centralize information on environmental radioactivity and to provide access to measurement results, a single database that includes an the results of measurements of radioactivity in the environment on the national territory is build and a new web-site www.mesure-radioactivite.fr is launched. It provides quick and easy access to this database. The quality of measurements is performed by a laboratory system through an ASN decision. Novel initiative in Europe, the French National Network for the Measurement of Environmental Radioactivity web-site gives the user keys to understand the measurement results on the radiological state of the environment. The site will be improved over the time taking into account the feedback of the users. (author)

246

Measurements of radioactive dusts at high altitude. Special investigation  

International Nuclear Information System (INIS)

For the nuclear explosion test conducted by North Korea on October 9 in 2006, the radioactive nuclides etc. contained in the airborne dust collected at high altitude by the Japan Air Self-Defence Force in the spatial investigation were measured. The artificial radioactive nuclides such as caesium and radioactive gas (gaseous radioiodine) were not detected. In addition, from the results of the gross beta activity measurement at high altitude in our country, it was shown that there is no appreciable difference between the activity levels of this period and those of usual periods. (author)

247

Radioactivity measurements for the ERMES project at the STELLA facility  

Directory of Open Access Journals (Sweden)

Full Text Available STELLA (SubTErranean Low Level Assay is the ultra low background facility of the Gran Sasso National Laboratories (L.N.G.S. in Italy. It is mainly devoted to material screening and rare events physics due to its very low radioactive background. Nevertheless, also environmental samples are measured within the collaboration with the ERMES (Environmental Radioactivity Monitoring for Earth Sciences project. After a short description of the facility some on-going applications within the ERMES project will be briefly presented. The usefulness of doing environmental radioactivity measurements in a deep underground laboratory will be shortly discussed.

Gallese B.

2012-04-01

248

A method to measure the absolute branching fractions of $\\Lambda_c$ decays  

CERN Document Server

It is proposed to exploit the decay of the meson $\\mbox{B}^+ \\rightarrow p \\pi^+ \\pi^+ \\overline{\\Sigma}_c^{--}$ and of its charge conjugate $B^-$ copiously produced at LHC to obtain a sample of $\\Lambda_c$ baryons through the strong decay $\\Sigma_c \\rightarrow \\Lambda_c \\pi$. The sample thus obtained is not affected by biases typically introduced by selections that depend on specific decay modes. Therefore it allows a measurement of the absolute branching fraction for the decay of the $\\Lambda_c$ baryon into $ p K \\pi$ or into other observable final states to be performed in a model independent manner. The accuracy that can be achieved with this method is discussed and it is shown that it would be either competitive with or an improvement over current measurements.

Contu, Andrea; Oldeman, Rudolf Gerhard Christiaan; Saitta, Biagio; Vacca, Claudia

2014-01-01

249

Absolute measurements of the high-frequency magnetic dynamics in high-Tc superconductors  

International Nuclear Information System (INIS)

The authors review recent measurements of the high-frequency dynamic magnetic susceptibility in the high-Tc superconducting systems La2-xSrxCuO4 and YBa2Cu3O6+x. Experiments were performed using the chopper spectrometers HET and MARI at the ISIS spallation source. The authors have placed their measurements on an absolute intensity scale, this allows systematic trends to be seen and comparisons with theory to be made. They find that the insulating S = 1/2 antiferromagnetic parent compounds show a dramatic renormalization in the spin wave intensity. The effect of doping on the response is to cause broadenings in wave vector and large redistributions of spectral weight in frequency

250

Diagnostics principle of microwave cut-off probe for measuring absolute electron density  

Science.gov (United States)

A generalized diagnostics principle of microwave cut-off probe is presented with a full analytical solution. In previous studies on the microwave cut-off measurement of weakly ionized plasmas, the cut-off frequency ?c of a given electron density is assumed to be equal to the plasma frequency ?p and is predicted using electromagnetic simulation or electric circuit model analysis. However, for specific plasma conditions such as highly collisional plasma and a very narrow probe tip gap, it has been found that ?c and ?p are not equal. To resolve this problem, a generalized diagnostics principle is proposed by analytically solving the microwave cut-off condition Re[?r,eff(? = ?c)] = 0. In addition, characteristics of the microwave cut-off condition are theoretically tested for correct measurement of the absolute electron density.

Jun, Hyun-Su

2014-08-01

251

From direct to absolute mass measurements: a study of the accuracy of ISOLTRAP  

International Nuclear Information System (INIS)

For a detailed study of the accuracy of the Penning trap mass spectrometer ISOLTRAP all expected sources of uncertainty were investigated with respect to their contributions to the uncertainty of the final result. In the course of these investigations, cross-reference measurements with singly charged carbon clusters 12C+n were carried out. The carbon cluster ions were produced by use of laser-induced desorption, fragmentation, and ionization of C60 fullerenes and injected into and stored in the Penning trap system. The comparison of the cyclotron frequencies of different carbon clusters has provided detailed insight into the residual systematic uncertainty of ISOLTRAP and yielded a value of 8*10-9. This also represents the current limit of mass accuracy of the apparatus. Since the unified atomic mass unit is defined as 1/12 of the mass of the 12C atom, it will be possible to carry out absolute mass measurements with ISOLTRAP in the future. (authors)

252

Static Absolute Force Measurement for Preloaded Piezoelements Used for Active Lorentz Force Detuning System  

CERN Document Server

To reach high gradients in pulsed operation of superconducting (SC) cavities an active Lorentz force detuning compensation system is needed. For this system a piezoelement can be used as an actuator (other option is a magnetostrictive device). To guarantee the demanded lifetime of the active element, the proper preload force adjustment is necessary. To determine this parameter an absolute force sensor is needed which will be able to operate at cryogenic temperatures. Currently, there is no calibrated commercial available sensor, which will be able to measure the static force in such an environment. The authors propose to use a discovered phenomenon to estimate the preload force applied to the piezoelement. The principle of the proposed solution based on a shape of impedance curve, which changes with the value of applied force. Especially, the position of resonances are monitored. No need of specialized force sensor and measurement in-situ are additional advantages of proposed method.

Sekalski, S P; Sekalski, S P

2004-01-01

253

Comb-calibrated frequency-modulated continuous-wave ladar for absolute distance measurements.  

Science.gov (United States)

We demonstrate a comb-calibrated frequency-modulated continuous-wave laser detection and ranging (FMCW ladar) system for absolute distance measurements. The FMCW ladar uses a compact external cavity laser that is swept quasi-sinusoidally over 1 THz at a 1 kHz rate. The system simultaneously records the heterodyne FMCW ladar signal and the instantaneous laser frequency at sweep rates up to 3400 THz/s, as measured against a free-running frequency comb (femtosecond fiber laser). Demodulation of the ladar signal against the instantaneous laser frequency yields the range to the target with 1 ms update rates, bandwidth-limited 130 ?m resolution and a ~100 nm accuracy that is directly linked to the counted repetition rate of the comb. The precision is <100 nm at the 1 ms update rate and reaches ~6 nm for a 100 ms average. PMID:23938965

Baumann, Esther; Giorgetta, Fabrizio R; Coddington, Ian; Sinclair, Laura C; Knabe, Kevin; Swann, William C; Newbury, Nathan R

2013-06-15

254

Absolute ultrasonic displacement amplitude measurements with a submersible electrostatic acoustic transducer  

Science.gov (United States)

An experimental technique for absolute measurement of ultrasonic wave particle displacement amplitudes in liquids is reported. The technique is capable of measurements over a frequency range of two decades with a sensitivity less than one angstrom. The technique utilizes a previously reported submersible electrostatic acoustic transducer (ESAT) featuring a conductive membrane stretched over a recessed electrode. An uncertainty analysis shows that the displacement amplitude of an ultrasonic plane wave incident on the ESAT can be experimentally determined to better than 2.3-4 percent, depending on frequency, in the frequency range of 0.5-15 MHz. Membranes with lower and more uniform areal densities can improve the accuracy and extend the operation to higher frequencies.

Yost, William T.; Cantrell, John H.

1992-01-01

255

Absolute measurements of the high-frequency magnetic dynamics in high-{Tc} superconductors  

Energy Technology Data Exchange (ETDEWEB)

The authors review recent measurements of the high-frequency dynamic magnetic susceptibility in the high-T{sub c} superconducting systems La{sub 2{minus}x}Sr{sub x}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 6+x}. Experiments were performed using the chopper spectrometers HET and MARI at the ISIS spallation source. The authors have placed their measurements on an absolute intensity scale, this allows systematic trends to be seen and comparisons with theory to be made. They find that the insulating S = 1/2 antiferromagnetic parent compounds show a dramatic renormalization in the spin wave intensity. The effect of doping on the response is to cause broadenings in wave vector and large redistributions of spectral weight in frequency.

Hayden, S.M. [Univ. of Bristol (United Kingdom). H.H. Wills Physics Lab.; Aeppli, G. [NEC Research Inst., Princeton, NJ (United States); Dai, P.; Mook, H.A. [Oak Ridge National Lab., TN (United States); Perring, T.G. [Rutherford Appleton Lab., Chilton (United Kingdom); Cheong, S.W. [Lucent Technologies, NJ (United States). Bell Labs.; Fisk, Z. [Florida State Univ., Tallahassee, FL (United States). Dept. of Physics; Dogan, F. [Univ. of Washington, Seattle, WA (United States). Dept. of Material Science and Engineering; Mason, T.E. [Univ. of Toronto, Ontario (Canada). Dept. of Physics

1997-08-07

256

Absolute activity measurement of 152Eu sources with a single detector  

International Nuclear Information System (INIS)

We investigated the possibility of absolute source activity measurements by a single gamma spectrometer. The measurements were performed for three (point, cylinder and Marinelly shaped) calibrated 152Eu sources. Making use of data on peak, sum-peak and total spectrum area in the single spectrum, we developed the activity determination method based on the dominant gamma cascades in the 152Eu decay. We have shown that spectral data of 152Eu point and Marinelli shaped source can yield activity information with uncertainty below 10%. - Highlights: ? Peak, sum-peak and total spectrum area in single spectrum were used for activity determination. ? For the 152Eu source the activity was determined from the dominant gamma cascades in the decay. ? The activity of point and Marinelly shaped sources was determined with uncertainty of less than 10%.

257

The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF  

International Nuclear Information System (INIS)

The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, ion-temperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

258

Evaluation of the systematic shifts and absolute frequency measurement of a single Ca+ ion frequency standard  

Science.gov (United States)

This paper provides a detailed description of the 40Ca+ optical frequency standard uncertainty evaluation and the absolute frequency measurement of the clock transition, as a summary and supplement for the published papers of Yao Huang et al. (Phys Rev A 84:053841, 1) and Huang et al. (Phys Rev A 85:030503, 2). The calculation of systematic frequency shifts, expected for a single trapped Ca+ ion optical frequency standard with a "clock" transition at 729 nm is described. There are several possible causes of systematic frequency shifts that need to be considered. In general, the frequency was measured with an uncertainty of 10-15 level, and the overall systematic shift uncertainty was reduced to below a part in 10-15. Several frequency shifts were calculated for the Ca+ ion optical frequency standard, including the trap design, optical and electromagnetic fields geometry and laboratory conditions, including the temperature condition and the altitude of the Ca+ ion. And we measured the absolute frequency of the 729-nm clock transition at the 10-15 level. An fs comb is referenced to a hydrogen maser, which is calibrated to the SI-second through the Global Positioning System (GPS). Using the GPS satellites as a link, we can calculate the frequency difference of the two hydrogen masers with a long distance, one in WIPM (Wuhan) and the other in National Institute of Metrology (NIM, Beijing). The frequency difference of the hydrogen maser in NIM (Beijing) and the SI-second calculated by BIPM is published on the BIPM web site every 1 month, with a time interval of every 5 days. By analyzing the experimental data obtained within 32 days of a total averaging time of >2 × 106 s, the absolute frequency of the 40Ca+ 4 s 2 S 1/2-3 d 2D5/2 clock transition is measured as 411 042 129 776 393.0 (1.6) Hz with a fractional uncertainty of 3.9 × 10-15.

Huang, Yao; Liu, Peiliang; Bian, Wu; Guan, Hua; Gao, Kelin

2014-01-01

259

Optical parameters Determination for absolute luminosity and total cross section measurements in ATLAS  

CERN Document Server

ALFA (Absolute Luminosity For ATLAS) aims at measuring the absolute luminosity for the ATLAS experiment with an incertitude down to 2-3 \\% and the total elastic cross section. The luminosity is related to the number of events, the highest the luminosity, the highest the number of events. This is, then, an important quantity for colliders like LHC (Large Hadron Collider). LHC is made of two beams circulating in two different beam pipes and colliding at four interaction points where the four physics experiments are located (ATLAS, CMS, ALICE, LHCb). ALFA detectors inserted into Roman Pots (RPs), have been placed around ATLAS at 240 m distance from the collision point (IP1) after six quadrupoles magnets and two dipoles defining the ALFA beam line which is part of the LHC ring.The detectors are made of scintillating optics fibers to catch elastic protons generated at IP1. These protons are tracked through the LHC magnets beam line which needs to be optimized in terms of optics parameters. We call high ? optics, ...

Cavalier, Sophie

260

Radioactivity measuring system of labelled biopolymers  

International Nuclear Information System (INIS)

System for determining the radioactivity of labelled biopolymers, comprising a bank of containers filled with aqueous solutions of biological samples containing biopolymers. This system features an electric drive to move the bank of containers step by step; a device for the acid precipitation of the biopolymers which sends determined amounts of co-precipitant and diatom suspension in an acid solution to the containers containing a biological sample; a system for taking precipitated samples from the containers; a system for filtering the precipitated biopolymers carrying out successive filterings; placing the deposit into suspension; dissolving the biopolymers and sending the labelled mixture labelled by the scintillation labeller to the detection chamber

 
 
 
 
261

Measurement of total body radioactivity in man  

International Nuclear Information System (INIS)

Techniques for the determination of whole-body radioactivity in man using uncollimated NaI(Tl) detectors have been studied. Geometrical effects and photon attenuation effects due to the different shapes of humans as well as due to varying in-vivo radioactivity distributions have been evaluated particularly for scanning-bed geometries and the chair geometry. Theoretically it is shown that the attenuation effects are generally dominating, for full-energy-peak pulse-range methods. For the application in radiation protection a cheap and simple chair-geometry unit has been constructed and used at various places distantly from the home-laboratory, for studies of body activity of Cs-137 in northern Sweden. High body activities were found particularly in reindeer-breeding Lapps. The elimination rate of Cs-137 in man was studied in the stationary whole-body counter in Lund as well as with the field-system. For the study of the performances at low and high photon energies clinical applications of methods for gastro-intestinal absorption of vitamin B12 (Co-57; 122 keV) and total body potassium determination (K-40; 1.46 MeV, K-42; 1.52 MeV) have been evaluated. Theoretical and experimental results as well as experiences of applications in radiation protection and medicine show that the scanning-bed geometry effectively evens out redistributional effects. For optimum results, however, scatter-energy pulse-ranges rather than full-energy-pea

262

Trace elements and radioactivity measurements in Tunisia  

International Nuclear Information System (INIS)

This work is a part of an undergoing activity at the radioanalytical laboratory at the National Center of Nuclear Science and Technology in Tunisia aiming at studying natural and man-made radioactivity and trace elements in environmental and industrial samples in the country. Several samples of environmental concern were analysed for radioactivity concentrations of 238U, 232Th, 40K and 137Cs. The environmental samples included clay soils and beach-sands from the north and the south of the country and the sahara in Tunisia, food products, and water samples and sediments from the Mediterranean sea. Technological products that may pose a radiological risk to the population included construction material such as cement, bricks and gravel, and phosphate products and by products such as phosphogypsum. The analytical methods employed were high-resolution gamma-spectrometry, instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. Results from the techniques employed are compared in terms of their accuracy, uncertainty and feasibility of performance in developing countries. The objectives are three fold: 1. To determine the concentrations of radioelement in environmental and industrial samples. 2. To investigate the impact of industrial and human activities on environmental pollution. 3. To compare several analytical techniques in terms of accuracy, uncertainty and feasibility. From the result, we can conclude that exposure to NORM and artifi conclude that exposure to NORM and artificial radiation from the samples analysed does not represent any major to human health

263

Study on influences of experimental factors on energy and absolute activity measurements of alpha-emitters  

International Nuclear Information System (INIS)

This work presents firstly a review of the fundamental results and conclusions obtained through alpha-spectrometry and alpha-counting, and the influence of energy straggling, energy loss, self-absorption and backscattering, on the determination of the energy and the absolute activity of alpha samples. Is is shown that the techniques of source fabrication and the methods of measurements play a capital influence on the obtained results. Moreover, measurements made by us, with a silicon surface barrier detector, show that the peak-asymmetry and peak-shift of an alpha-spectrum increases with the angle of emission, and that the magnitude of this effect depends on the thickness and homogeneity of the sample, as well as on the geometry of the measuring system. Through an analysis of the angular distribution of the emitted particles, the degree of isotropy of some thin Am sup(241) sources was measured and the influence of source backing and the geometry was analysed. We can conclude that, in general, there is a larger precision in measurements made under very small solid angles around the normal to the sample, and we enphasize the necessary cares required on the production of the source and on the set up of the measuring system. (author)

264

Coincidence system for the absolute measurement of radionuclides activity using a liquid scintillator  

International Nuclear Information System (INIS)

A system for the standartization of radioisotopes activity using liquid scintillator detector was developed. The system was set up at Nuclear Metrology Laboratory - L.M.N. (Nuclear Physics Division - IEA). The system performance was checked by absolute activity measurements for two radioisotopes, 60Co and 241Am. The activities were determined by the 4?(?, ?-?) coincidence method. An accuracy of the order of 99,8% was obtained. The results for 60Co were compared with those obtained by 4??-? coincidence method using a proportional counter at L.M.N., while the results for 241Am were compared with those obtained through the linear extrapolation method using the same liquid scintillator. Compared to other systems, the advantages of this one are the simplicity and the short time spent in the sample preparation, and the negligible self-absorption. (Author)

265

Absolute Ultrasound Attenuation Measurements in Superfluid 3He in 98% Aerogel by Direct Transmission  

Science.gov (United States)

Systematic investigations on the effect of static disorder on p-wave superfluid 3He have been made possible by utilizing the unique structure of high porosity silica aerogel. For the past 10 years, a burst of experimental efforts revealed that three distinct superfluid phases exists. We have performed longitudinal ultrasound (9.5 MHz) attenuation measurements in the B-phase of the superfluid 3He in 98% aerogel. The absolute attenuation was determined by direct propagation of sound pulses through the medium in a wide range of temperatures, down to 200 ?K, for sample pressures of 10 and 29 bars. Our results provide direct information on the zero-energy density of states of the superfluid phase in aerogel originating from impurity scattering.

Lee, Y.; Choi, H. C.; Masuhara, N.; Moon, B. H.; Bhupathi, P.; Meisel, M. W.; Mulders, N.

2007-09-01

266

Measurement of the Absolute Proton and Helium Flux at the Top of the Atmosphere using IMAX  

DEFF Research Database (Denmark)

The balloon-borne experiment IMAX launched from Lynn Lake, Canada in 1992 has been used to measure the cosmic ray proton and helium spectra from 0.2 GV to approximately 100 GV. The IMAX apparatus was designed to search for antiprotons and light isotopes using a superconducting magnet spectrometer with ancillary scintillators, time-of-flight, and aerogel cherenkov detectors. High resolution drift chambers and MWPCs were used as the tracking devices. Using redundant detectors, an extensive examination of the instrument efficiency was carried out. We present the absolute spectra of protons and helium corrected to the top of the atmosphere. The IMAX experiment was supported by NASA: RTOP 353-87-02 (GSFC), grants NAGW-1919 (Caltech) and NAGW-1418 (NMSU), and in Germany by the DFG and the BMFT. ^1 present address Max-Planck-Institut für Extraterrestrische Physik

Rasmussen, Ib Lundgaard

1996-01-01

267

Simple on-line method of measuring the absolute ionization efficiency of an ion source  

International Nuclear Information System (INIS)

We report a new method of measuring the absolute ionization efficiency of an ion source, which is independent of gas flow rate fed to an ionizer and of detection efficiency of the resulting ions. The method is based on the fact that when a pulsed alternate potential is applied between the ionizer and an electrode set outside near its exit hole, ions stored inside the ionizer while the potential is repulsive for the ions are flushed out as soon as it becomes attractive. It is shown that when the duty factor and repetition rate of the applied potential are properly chosen, the magnitude of this bunching effect can simply be expressed only by the ionization efficiency. Since its magnitude can quickly be evaluated, for example, by observing the time dependence of the bunched ion current in an oscilloscope, it provides a simple and reliable way for on-line diagnostics of the source. (author)

268

Absolute Polarization Measurements at RHIC in the Coulomb Nuclear Interference Region  

CERN Document Server

The Relativistic Heavy Ion Collider at Brookhaven National Laboratory provides polarized proton beams for the investigation of the nucleon spin structure. For polarimetry, carbon-proton and proton-proton scattering is used in the Coulomb nuclear interference region at small momentum transfer ($-t$). Fast polarization measurements of each beam are carried out with carbon fiber targets at several times during an accelerator store. A polarized hydrogen gas jet target is needed for absolute normalization over multiple stores, while the target polarization is constantly monitored in a Breit-Rabi polarimeter. In 2005, the jet polarimeter has been used with both RHIC beams. We present results from the jet polarimeter including a detailed analysis of background contributions to asymmetries and to the beam polarization.

Eyser, K O; Bravar, A; Bunce, G; Dhawan, S; Gill, R; Haeberli, W; Huang, H; Jinnouchi, O; Makdisi, Y; Nakagawa, I; Nass, A; Okada, H; Stephenson, E; Svirida, D; Wise, T; Wood, J; Zelenski, A

2007-01-01

269

Measurement of D0??l?(Kl?) Form Factors and Absolute Branching Fractions  

International Nuclear Information System (INIS)

Using a 282 fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider, we study D0 decays to K-l+? and ?-l+? final states. The D0 flavor and momentum are tagged through a full reconstruction of the recoiling charm meson and additional mesons from fragmentation. The reconstruction method provides very good resolution in neutrino momentum and in q2=(pl+p?)2. Normalizing to the total number of D0 tags, we measure the absolute branching fractions to be B(D0?Kl?)=(3.45±0.07stat±0.20syst)% and B(D0??l?)=(0.255±0.019stat±0.016syst)% and the semileptonic form factors (within the modified pole model) f+K(0)=0.695±0.007stat±0.022syst and f+?(0)=0.624±0.020stat±0.030syst

270

Particle energy absolute calibration by measuring frequency of polarized electron spin procession on the VEPP-4  

International Nuclear Information System (INIS)

The method of absolute energy calibration of the VEPP-4 storage ring based on resonance depolarization of a polarized beam which is used for determining the spin precession frequency of polarized protons is described. The resonance effect on the beam is caused by an electromagnetic field. When the spin precession frequency coincides with the field frequency the beam is depolarized. The depolarization phenomenon is detected by measuring changes in the counting rate of particles departing the beam due to the effect of internal scattering which cross section depends on the degree of beam polarization. The resonance depolarization method is used for calibrating beam energy in the VEPP-4 with an accuracy not worse than 5x10-5

271

Natural radioactivity measurements at the proposed nuclear power plant site  

International Nuclear Information System (INIS)

Natural radioactivity measurement in the Philippines aims to establish baseline radioactivity levels in the environment of items essential to man. In this article, results of the environmental surveillance conducted in Bagac, Bataan from 1973 to 1974 are presented. Analyses were made on air parti-culates, sea and fresh water, grass, and soil samples for gross beta-gamma activities. Results obtained showed activity levels below the maximum permissible concentration recommended by the International Committee on Radiation Protection (ICRP)

272

Absolute measurements of the fast neutron capture cross section of 115In  

International Nuclear Information System (INIS)

The 115In(n,#betta#)/sup 116m1/In cross section has been absolutely determined at neutron energies of 23, 265 and 964 keV. These energies are the median neutron energies of the three photo-neutron sources. Sb-Be, Na-CD2 and Na-Be, utilized in this work. The measurements are independent of other cross section data except for corrections amounting to less than 10%. Independent determinations of the reaction rate, detector efficiency, neutron source strength, scalar flux and target masses were performed. Reaction rates were determined by beta counting of the /sup 116ml/In decay activity using a 4? gas flow proportional counter. Detector efficiency was measured using 4?#betta#-#betta# coincidence counting techniques and the foil absorber method of efficiency extrapolation for correction of complex decay scheme effects. Photoneutron source emission rates were determined by intercomparison with the NBS-II calibrated 252Cf spontaneous fission neutron source in the University of Michigan Manganese Bath. The normalized scalar flux was calculated from the neutron emission angular distribution results of the Monte Carlo computer program used to model neutron and gamma transport in the source. Target mass determinations were made with a microbalance. Correction factors were applied for competing reaction activities, neutron scattering from experiment components, room-return induced activities, spectral effects in the manganese bath and the neutron energy spectra of the photoneutron sources. Experimental cross section results were normalized to the source median energy using energy spectra d cross section shape data. The absolute cross sections obtained for the 115In(n,#betta#)/sup 116ml/In reaction were 588 +- 12, 196 +- 4 and 200 +- 3 millibarns at 23, 265 and 964 keV, respectively

273

Determination and control measurements of coincidence devices used for activity measurements by absolute method  

International Nuclear Information System (INIS)

Description of the method of performing determination and control measurements is given which are done on the measuring device with 4?-proportional counter under elevated pressure. The device is working according to the coincidence method. Accuracy of this method greatly depends on determination of electronic parameters and different correction facters. Control measurements are done for testing the state of the counter and electronic circuit of the device for determination of the energy equivalent for descrimination level of 4?-proportional counter; for determination of the resolution ability of the counter, for determination of first and coincidence time. Determination measurements are done for testing a tuning of the device for measurement of the given nuclide and include a turing of ?-chanel; measurement of activity of ?-emitter with continious spectrum; measurement of activity of nuclides with discrete spectrum; turing of ?-chanel; turing of the coincidence circuit. The method of plotting of the curve for data extrapolation is given

274

Application of the 4 pigammaMethod to the Absolute Standardization of Radioactive Sources of Positron Emitters  

International Nuclear Information System (INIS)

We discuss the application of the method known as 4 pigammacountingto the standardization of positron emitters. Monte Carlo simulations are used to calculate the detection efficiency of positrons emitted by the nuclides 22Na and 18F. Two experimental setups are used, both based on a NaI(Tl) well detector. The results of the standardizations are in good agreement with those obtained by other methods. It is shown that the 4 pigammamethod can be successfully used for the absolute standardization of sources of positron emitters. (Author) 23 refs

275

A measurement of the absolute neutron beam polarization produced by an optically pumped sup 3 He neutron spin filter  

CERN Document Server

The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized sup 3 He spin filter and a relative transmission measurement technique. sup 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method.

Rich, D R; Crawford, B E; Delheij, P P J; Espy, M A; Haseyama, T; Jones, G; Keith, C D; Knudson, J; Leuschner, M B; Masaike, A; Masuda, Y; Matsuda, Y; Penttilae, S I; Pomeroy, V R; Smith, D A; Snow, W M; Szymanski, J J; Stephenson, S L; Thompson, A K; Yuan, V

2002-01-01

276

Absolute calibration method for laser megajoule neutron yield measurement by activation diagnostics  

Science.gov (United States)

The laser megajoule (LMJ) and the National Ignition Facility (NIF) plan to demonstrate thermonuclear ignition using inertial confinement fusion (ICF). The neutron yield is one of the most important parameters to characterize ICF experiment performance. For decades, the activation diagnostic was chosen as a reference at ICF facilities and is now planned to be the first nuclear diagnostic on LMJ, measuring both 2.45 MeV and 14.1 MeV neutron yields. Challenges for the activation diagnostic development are absolute calibration, accuracy, range requirement, and harsh environment. At this time, copper and zirconium material are identified for 14.1 MeV neutron yield measurement and indium material for 2.45 MeV neutrons. A series of calibrations were performed at Commissariat à l'Energie Atomique (CEA) on a Van de Graff facility to determine activation diagnostics efficiencies and to compare them with results from calculations. The CEA copper activation diagnostic was tested on the OMEGA facility during DT implosion. Experiments showed that CEA and Laboratory for Laser Energetics (LLE) diagnostics agree to better than 1% on the neutron yield measurement, with an independent calibration for each system. Also, experimental sensitivities are in good agreement with simulations and allow us to scale activation diagnostics for the LMJ measurement range.

Landoas, Olivier; Yu Glebov, Vladimir; Rossé, Bertrand; Briat, Michelle; Disdier, Laurent; Sangster, Thomas C.; Duffy, Tim; Marmouget, Jean Gabriel; Varignon, Cyril; Ledoux, Xavier; Caillaud, Tony; Thfoin, Isabelle; Bourgade, Jean-Luc

2011-07-01

277

Absolute production rate measurements of nitric oxide by an atmospheric pressure plasma jet (APPJ)  

Energy Technology Data Exchange (ETDEWEB)

Tunable diode laser absorption spectroscopy (TDLAS) has been applied to measure the absolute production rate of NO molecules in the gas phase of an atmospheric pressure plasma jet (APPJ) operating at rf (13.56 MHz) in argon with small (up to 1%) admixtures of air. The resulting NO production rates were found to be in the range (0.1-80) x 10{sup -3} sccm or (0.05-35) x 10{sup 18} molecules s{sup -1} depending on the experimental conditions. Maximum rates were obtained at 0.2% air. For TDLAS measurements the APPJ was arranged inside an astigmatic multi-pass cell of Herriott type with 100 m absorption length. The insertion into a closed volume differs slightly from the normal, open operation with the jet propagating freely into air. Therefore, the measuring results are compared with optical emission of the open jet to verify equivalent experimental conditions. The dependence of the optical emission of NO (237 nm) on power and gas mixture has been measured. The similar shape of the dependence of absorption and emission signals gives evidence that the comparability of experimental conditions is sufficiently satisfied. It is concluded that the NO production rate of the APPJ in ambient air can be characterized using TDLAS and provides reliable results in spite of differing experimental conditions due to the set-up.

Pipa, A V; Bindemann, T; Foest, R; Kindel, E; Roepcke, J; Weltmann, K-D [Leibniz-Institut fuer Plasmaforschung and Technologie e.V. (INP), Felix-Hausdorff Strasse 2, D-17489 Greifswald (Germany)], E-mail: foest@inp-greifswald.de

2008-10-07

278

Absolute measurement of the isotopic ratio of a water sample with very low deuterium content  

International Nuclear Information System (INIS)

The presence of H3+ ions which are indistinguishable from HD+ ions presents the principal difficulty encountered in the measurement of isotopic ratios of water samples with very low deuterium contents using a mass spectrometer. Thus, when the sample contains no deuterium, the mass spectrometer does not indicate zero. By producing, in situ, from the sample to be measured, water vapor with an isotopic ratio very close to zero using a small distilling column, this difficulty is overcome. This column, its operating parameters, as well as the way in which the measurements are made are described. An arrangement is employed in which the isotopic ratios can be measured with a sensitivity better than 0.01 x 10-6. The method is applied to the determination of the isotopic ratios of three low deuterium content water samples. The results obtained permit one to assign to the sample with the lowest deuterium content an absolute value equal to 1.71 ± 0.03 ppm. This water sample is a primary standard from which is determined the isotopic ratio of a natural water sample which serves as the laboratory standard. (author)

279

Absolute measurement of radiation losses of a tokamak in the region of ultrasoft X-radiation  

International Nuclear Information System (INIS)

In this work experiments were performed to investigate the question to which extent spectroscopic measurements in the ultrasoft X-ray region (lambda=1-10nm) are a useful technique for diagnosing the relatively cool edge region (Tsub(e)approx.=100-200 eV) of fusion-oriented plasmas. Object of these measurements was the plasma centre of a small tokamak where the plasma parameters are comparable to those in the edge region mentioned above. The measurements were done with a Bragg-spectrometer using either TAP (2d=2.59 nm) or lead stearate (2d=10.04 nm) as analyzer crystal. This allowed to cover the whole spectrum between 0.5 and 9 nm with one instrument. Using a photon-counting detector the spectrometer/detector system was absolutely calibrated by measuring the transmission of its different components by means of monochromatic X-ray radiation. For the investigated tokamak plasma intense line spectra in the region 1.4 nm =4.4 nm have been observed, where the former was caused by the high ionization stages of oxygen (OVII and OVIII), whereas the latter could be explained by Ar- to Na-like ions of the metallic impurities Fe, Cr, and Ni. (orig./HT)

280

A new way of measuring apoptosis by absolute quantitation of inter-nucleosomally fragmented genomic DNA.  

Science.gov (United States)

Several critical events of apoptosis occur in the cell nucleus, including inter-nucleosomal DNA fragmentation (apoptotic DNA) and eventual chromatin condensation. The generation of apoptotic DNA has become a biochemical hallmark of apoptosis because it is a late 'point of no return' step in both the extrinsic (cell-death receptor) and intrinsic (mitochondrial) apoptotic pathways. Despite investigators observing apoptotic DNA and understanding its decisive role as a marker of apoptosis for over 20 years, measuring it has proved elusive. We have integrated ligation-mediated PCR and qPCR to design a new way of measuring apoptosis, termed ApoqPCR, which generates an absolute value for the amount (picogram) of apoptotic DNA per cell population. ApoqPCR's advances over current methods include a 1000-fold linear dynamic range yet sensitivity to distinguish subtle low-level changes, measurement with a 3- to 4-log improvement in sample economy, and capacity for archival or longitudinal studies combined with high-throughput capability. We demonstrate ApoqPCR's utility in both in vitro and in vivo contexts. Considering the fundamental role apoptosis has in vertebrate and invertebrate health, growth and disease, the reliable measurement of apoptotic nucleic acid by ApoqPCR will be of value in cell biology studies in basic and applied science. PMID:22544708

Hooker, David J; Mobarok, Masqura; Anderson, Jenny L; Rajasuriar, Reena; Gray, Lachlan R; Ellett, Anne M; Lewin, Sharon R; Gorry, Paul R; Cherry, Catherine L

2012-08-01

 
 
 
 
281

Absolute calibration method for laser megajoule neutron yield measurement by activation diagnostics.  

Science.gov (United States)

The laser megajoule (LMJ) and the National Ignition Facility (NIF) plan to demonstrate thermonuclear ignition using inertial confinement fusion (ICF). The neutron yield is one of the most important parameters to characterize ICF experiment performance. For decades, the activation diagnostic was chosen as a reference at ICF facilities and is now planned to be the first nuclear diagnostic on LMJ, measuring both 2.45 MeV and 14.1 MeV neutron yields. Challenges for the activation diagnostic development are absolute calibration, accuracy, range requirement, and harsh environment. At this time, copper and zirconium material are identified for 14.1 MeV neutron yield measurement and indium material for 2.45 MeV neutrons. A series of calibrations were performed at Commissariat a? l'Energie Atomique (CEA) on a Van de Graff facility to determine activation diagnostics efficiencies and to compare them with results from calculations. The CEA copper activation diagnostic was tested on the OMEGA facility during DT implosion. Experiments showed that CEA and Laboratory for Laser Energetics (LLE) diagnostics agree to better than 1% on the neutron yield measurement, with an independent calibration for each system. Also, experimental sensitivities are in good agreement with simulations and allow us to scale activation diagnostics for the LMJ measurement range. PMID:21806179

Landoas, Olivier; Glebov, Vladimir Yu; Rossé, Bertrand; Briat, Michelle; Disdier, Laurent; Sangster, Thomas C; Duffy, Tim; Marmouget, Jean Gabriel; Varignon, Cyril; Ledoux, Xavier; Caillaud, Tony; Thfoin, Isabelle; Bourgade, Jean-Luc

2011-07-01

282

A portable system for measuring the absolute geographic location of distant objects  

Science.gov (United States)

This contribution presents the development of a lightweight, man-portable system for measuring the absolute geographic location of distant objects. The system is built entirely from COTS (Commercial Of-The-Shelf) components that are controlled using custom software and hardware solutions. It consists of a laser rangefinder, an electronic compass and inclinometer, an optical incremental encoder, a GPS receiver, a CMOS camera, an LCOS viewfinder and an FPGA module that serves as a system controller. With the use of the FPGA, low power consumption and high processing power was achieved. The user interface comprises the viewfinder and a multidirectional button. While performing measurements, the live image of the target, sensor data and calculated coordinates are displayed in the viewfinder. The measuring system also features an SD card slot for data storage and WLAN connectivity to transfer the acquired data to a geographic information system. The contribution also presents the results of field tests used to verify the system operation and Monte Carlo simulations employed to evaluate its measuring characteristics.

Kuscer, Lovro; Diaci, Janez

2010-10-01

283

New method for absolute measurement of neutron flux in reactors operated at high power levels  

International Nuclear Information System (INIS)

The objective of this thesis is to develop and study two methods of neutron measurements in nuclear reactors - new methods for measuring fast neutron fluxes, and Li6 semiconductor neutron spectrometer. It contains four chapters: Chapter I, Introduction covers the explanation of the need for neutron measurements in the reactor, and critical consideration of the existing methods for fast neutron flux measurements as well as methods for measuring the fast neutron spectra. Chapter II describes theoretical basis of semiconductor counters operation and their most important properties. Chapter III includes the description of the method developed by the author, long-tube method, and the results obtained by applying this method with the special emphasis on absolute measurements of fast neutron flux. Advantages and limitations of this method are discussed at the end of this chapter. Chapter IV contains intercomparison of the existing semiconductor spectrometers and emphasis of their positive and negative properties. A critical analysis of the results obtained by Li6 spectrometer with flat geometry in included. A new type of Li6 semiconductor spectrometer is described. Its properties are experimentally determined and it was compared to the classical Li6 spectrometer. Most of the experiments were done in the Physics Laboratory and at RA and RB reactors in the 'Boris Kidric' Institute of Nuclear Sciences in Vinca, and some at reactor in McMaster University, Hamilton, Canada. Experiments concerned with registering particles scattering were done at the Lockheed research reactor during fall 1963 in Belgrade. Neutron fluxes and spectra were measured by semiconductor counters improved and adapted for neutronic measurements by the author

284

Radiation Protection Research: Low-level Radioactivity Measurements  

International Nuclear Information System (INIS)

The objectives of the research performed in the area of low-level radioactivity measurements are (1) to maintain and develop techniques for the measurement of low-level environmental and biological samples, (2) to measure these samples by means of low-background counters (liquid scintillators, proportional counters, ZnS counters, alpha spectrometry), (3) to support and advice the nuclear and non-nuclear industry in matters concerning radioactive contamination and/or low-level radioactivity measurements; (4) to maintain the quality assurance system according to the EN45001 standard; and (5) to assess the internal dose from occupational intakes of radionuclides of workers of the nuclear industry. Progress and achievements in these areas in 1999 are reported. Particular emphasis is SCK-CEN's contribution to the EULEP-EURADOS Action Group on 'Derivation of parameter values for application in the new model of the human respiratory tract for occupational exposure'

285

Measured radioactivity data acquisition and evaluation system (REA)  

International Nuclear Information System (INIS)

In Germany, authorities in the Federal States are obliged to monitor the environment for radioactivity. Various institutions run radioactivity measurements for this purpose. The measured results are made available to the competent authorities in a variety of ways. Computer systems are now used for central collection and evaluation of these data. LfU has developed a concept to support by DP technologies also the procedures between the measurement site and the central authority. This facilitates data acquisition and speeds up data transmission. The REA concept will streamline procedures and improve data quality. (orig.)

286

Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy  

International Nuclear Information System (INIS)

The first absolute wind velocities above the cloud-tops were obtained during four planetary phases spanning 82 percent of a synodic period. Bean-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 microns R(8) (obtained at sub-Doppler resolution), sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than +/- 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam and 1-2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds definitively established a dominant subsolar-antisolar circulation in the lower thermosphere. A retrograde zonal component was also suggested. Beam-integrated winds were modelled with a 100 x 100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s equatorial velocity. Detection of a significant zonal compity. Detection of a significant zonal component indicates upper thermospheric super-rotation may be coupled to, hence pumped by, cloud level super-rotation. Early heterodyne mesospheric wind measurements were re-examined based on laser stability test results

287

Degree of polarization as a cross-correlation detector for absolute distance measurement  

Science.gov (United States)

We present an absolute distance measurement concept based on pulse frequency repetition (PRF) sweep with a mode-locked laser diode. This technique requires a Michelson interferometer, a mode-locked laser source and a cross-correlation detector. The role of the cross-correlator is to analyze the state of superposition of a pair of pulses, one travelling over the reference arm of the interferometer, the other, corresponding to the measuring arm, travelling from the apparatus to the target and reflected back. Using two distinct laser pulse repetition frequency and knowing the cross-correlation peak position at reference arm of the interferometer for each frequency, it's possible to obtain the length of the measuring arm, i.e., a distance measuring. The main techniques for performing pulse correlation are based in 2nd order effects over second harmonic crystal (SHG) or a two-photon absorption (TPA) process in a semiconductor junction. Both SHG and TPA methods require reasonably high pulse energies to achieve fair signal to noise ratios. The use Degree of Polarization (DOP) technique for cross-correlation detection allows the use of optical powers as low as -60 dBm. Such high sensitivity can be very convenient for low energy pulse sources such is the case of high frequency mode-locked laser diodes. The DOP technique can however limit the maximum measurement range, constrained by the loss of coherence of the laser source for longer distances. In this paper we present the first results of this measurement concept, based in the DOP correlator, discussing the main limitations of this technique for long distance measurements.

Castro Alves, D.; Abreu, Manuel; Cabral, Alexandre; Rebordão, J. M.

2013-11-01

288

Optical measurement of absolute flatness with the deflectometric measurement systems at PTB  

International Nuclear Information System (INIS)

Highly accurate flatness measurements are needed for synchrotron optics, optical flats, or optical mirrors. Recently, two new scanning deflectometric flatness measurement systems have been installed at the Physikalisch-Technische Bundesanstalt (PTB). The two systems (one system for horizontal and the other for vertical specimens) can measure specimens with sizes up to one metre with an expected uncertainty in the sub-nanometre range. In addition to the classical deflectometric procedure, also the 'extended shear angle difference (ESAD)' and the 'exact autocollimation deflectometric scanning (EADS)' procedures are implemented. The lateral resolution of scanning deflectometric techniques is limited by the aperture of the angle measurement system, usually an autocollimator with typical apertures of a few millimetres. With the EADS procedure, the specimen is scanned with an angular null instrument which has the potential to improve the lateral resolution down to the sub-millimetre region. A new concept and design of an appropriate angular null instrument are presented and discussed.

289

Absolute high-resolution Se+ photoionization cross-section measurements with Rydberg-series analysis  

International Nuclear Information System (INIS)

Absolute single photoionization cross-section measurements for Se+ ions were performed at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory using the photo-ion merged-beams technique. Measurements were made at a photon energy resolution of 5.5 meV from 17.75 to 21.85 eV spanning the 4s24p3 4S3/2o ground-state ionization threshold and the 2P3/2o,2P1/2o,2D5/2o, and2D3/2o metastable state thresholds. Extensive analysis of the complex resonant structure in this region identified numerous Rydberg series of resonances and obtained the Se2+ 4s24p23P2 and 4s24p21S0 state energies. In addition, particular attention was given to removing significant effects in the measurements due to a small percentage of higher-order undulator radiation.

290

Luminosity measurement method for the LHC: Event selection and absolute luminosity determination  

International Nuclear Information System (INIS)

In our earlier papers Krasny et al. [1,2] have proposed a new luminosity measurement method which uses lepton pairs produced in peripheral collisions of the LHC beam particles, and identified the requirements for a new, specialized luminosity detector which is indispensable for their efficient on-line selection. In this paper we use the base-line detector model, with no precise timing capabilities, to evaluate the statistical and systematic accuracy of the method. We propose the complete event selection procedure and demonstrate that it allows to collect a sufficiently large sample of e+e? pairs to achieve a better than 1% statistical accuracy of the luminosity measurement over less than one-month-long running time intervals. We argue that the absolute luminosity measurement systematic errors can be kept below 1%. The proposed method can be directly applied to the LHC running periods for which the machine instantaneous luminosity does not exceed the L=1033s?1cm?2 value. Two ways extending the method to the large pile-up periods corresponding to higher instantaneous luminosities are proposed

291

An absolute measurement of 252Cf prompt fission neutron spectrum at low energy range  

International Nuclear Information System (INIS)

Prompt neutron energy spectrum at low energies (25 keV252Cf spontaneous fission has been measured with a time-of-flight technique on a 30 cm flight-path. Ionization chamber and lithium-glass were used as fission fragment and neutron detectors, respectively. Lithium glasses of NE-912 (containing 6Li) and of NE-913 (containing 7Li) 45 mm in diameter and 9.5 mm in thickness have been employed alternatively, for the registration of fission neutrons and gammas. For the correct determination of the multiscattering effects - the main difficulty of the low energy neutron spectrum measurements - a special geometry for the neutron detector was used. Special attention was paid also to the determination of the absolute efficiency of the neutron detector. The real response function of the spectrometer was determined by a Monte-Carlo calculation. The scattering material content of the ionization chamber containing a 252Cf source was minimized. As a result of this measurement a prompt fission neutron spectrum of Maxwell type with a T=1.42 MeV parameter was obtained at this low energy range. We did not find any neutron excess or irregularities over the Maxwellian. (author)

292

Absolute measurement of the effective nonlinearities of KTP and BBO crystals by optical parametric amplification.  

Science.gov (United States)

Absolute magnitudes of the effective nonlinearity, deff, were measured for seven KTP and six BBO crystals. The d(eff), were derived from the parametric gain of an 800-nm signal wave in the sample crystals when they were pumped by the frequency-doubled, spatially filtered light from an injectionseeded, Q-switched Nd:YAG laser. The KTP crystals, all type II phase matched with propagation in the X-Z plane, had d(eff) values ranging from 1.97 to 3.50 pm/V. Measurements of gain as a function of phase velocity mismatch indicate that two of the KTP crystals clearly contain multiple ferroelectric domains. For five type I phase-matched BBO crystals, d(eff) ranged from 1.76 to 1.83 pm/V, and a single type II phase-matched BBO crystal had a d(eff) of 1.56 pm/V. The uncertainty in our measurements of d(eff) values is ±5% for KTP and ±10% for BBO. PMID:21085331

Armstrong, D J; Alford, W J; Raymond, T D; Smith, A V

1996-04-20

293

Diffusion coefficient measurements with radioactive tracer technique  

International Nuclear Information System (INIS)

A measuring cell and a new method were developed to study chloride ion diffusion through thin layers and to measure diffusion coefficient. ?-radiation of the tracer was detected making use of Cherenkov radiation. The chamber developed is suitable for diffusion test with any ?-decay nuclide with a maximum energy higher than the Cherenkov threshold referring to water. The results obtained were checked by GM counting. The method was used for testing paint films and coating systems. The diffusion developed in the layer was computer simulated and the results were compared to measured data. (author)

294

Influence of radioactive impurities on SIR measurements  

Energy Technology Data Exchange (ETDEWEB)

The correction usually applied to an SIR measurement in the presence of a gamma-ray emitting impurity is presented and explained. The method of calibration of a Ge(Li) spectrometer is briefly described. It is used to look for impurities when SIR measurements show inconsistencies. An example is presented where a {sup 103}Ru impurity was discovered in a {sup 99}Mo solution. The correction applied compensates for the decrease of around 0.2% per day observed in the SIR measurements of this {sup 99}Mo ampoule.

Michotte, C

2000-03-01

295

Measurement methodology of natural radioactivity in the thermal establishments  

International Nuclear Information System (INIS)

The thermal baths have been identified as an activity susceptible to expose to ionizing radiations the workers through the natural sources of radon and radon 220. The new regulation obliges these facilities to realize radioactivity measurements. The principal ways of exposure are radon and its daughters inhalation,, exposure to gamma radiation, ingestion of radioelements in thermal waters. I.R.S.N. proposes two methods of measurements of the natural radioactivity in application to the regulation relative to the protection of persons and workers. Some principles to reduce exposure to radon are reminded. (N.C.)

296

In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope  

Energy Technology Data Exchange (ETDEWEB)

The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

Ackermann, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Ajello, M.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Allafort, A.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm; Baldini, L.; /INFN, Pisa; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bloom, E.D.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Bouvier, A.; /UC, Santa Cruz; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /SLAC /KIPAC, Menlo Park; Buson, S.; /INFN, Padua /Padua U. /CSIC, Catalunya /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /IASF, Milan /DAPNIA, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Unlisted, US /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /ASDC, Frascati /Perugia U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Montpellier U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Ecole Polytechnique /Hiroshima U. /Stanford U., HEPL /SLAC /KIPAC, Menlo Park /Bari Polytechnic /INFN, Bari /INFN, Bari /NASA, Goddard /INFN, Perugia /Perugia U.; /more authors..

2012-09-20

297

From direct to absolute mass measurements a study of the accuracy of ISOLTRAP  

CERN Document Server

For a detailed study of the accuracy of the Penning trap mass spectrometer ISOLTRAP all expected sources of uncertainty were investigated with respect to their contributions to the uncertainty of the final result. In the course of these investigations, cross-reference measurements with singly charged carbon clusters $^{12}$C$^{+}_{n}$ were carried out. The carbon cluster ions were produced by use of laser-induced desorption, fragmentation, and ionization of C$_{60}$ fullerenes and injected into and stored in the Penning trap system. The comparison of the cyclotron frequencies of different carbon clusters has provided detailed insight into the residual systematic uncertainty of \\acro{ISOLTRAP} and yielded a value of $8 \\cdot 10^{-9}$. This also represents the current limit of mass accuracy of the apparatus. Since the unified atomic mass unit is defined as 1/12 of the mass of the $^{12}$C atom, it will be possible to carry out absolute mass measurements with \\acro{ISOLTRAP} in the future.\\\\[1\\baselineskip] PACS...

Kellerbauer, A G; Bollen, G; Herfurth, F; Kluge, H J; Kuckein, M; Sauvan, E; Scheidenberger, C; Schweikhard, L; 10.1140/epjd/e2002-00222-0

2003-01-01

298

An Absolute Measurement of the Cosmic Microwave Background Radiation Temperature at 10.7 GHz  

CERN Document Server

A balloon-borne experiment has measured the absolute temperature of the cosmic microwave background radiation (CMBR) at 10.7 GHz to be Tcmbr = 2.730 +- .014 K. The error is the quadratic sum of several systematic errors, with statistical error of less than 0.1 mK. The instrument comprises a cooled corrugated horn antenna coupled to a total-power radiometer. A cryogenic mechanical waveguide switch alternately connects the radiometer to the horn and to an internal reference load. The small measured temperature difference (<= 20 mK) between the sky signal and the reference load in conjunction with the use of a cold front end keeps systematic instrumental corrections small. Atmospheric and window emission are minimized by flying the instrument at 24 km altitude. A large outer ground screen and smaller inner screen shield the instrument from stray radiation from the ground and the balloon. In-flight tests constrain the magnitude of ground radiation contamination, and low level interference is monitored through ...

Staggs, S T; Meyer, S; Wilkinson, D T

1996-01-01

299

Use of proportional gas scintillator in absolute measurements of alpha-gamma emitter activities  

International Nuclear Information System (INIS)

The absolute activity of U-235 contained in a U3 O8 sample was measured utilizing a sum-coincidence circuit which selects only the alpha particles which are simultaneous with the 143 KeV and 186 KeV gamma radiations from the Th-231 (product nucleus). The alpha particles were detected by means of a new type of a gas scintillating chamber, in which the light emitted by excitation of the gas atoms, due to the passage of a charged incoming particle, has its intensity increased by the action of an applied electric field. The gamma radiations were detected by means of a NaI(Tl) 1'' x 11/2'' scintillation detector. The value obtained for the half-life of U-235 was compared with the data available from various observers which used different experimental techniques. It is shown tht the results, are in excellent agreement with the best international data available on the subject and that, therefore, the sum-coincidence technique constitutes an important method for such measurements. (Author)

300

Gravity change from repeated absolute measurements in Estonia, Latvia and Lithuania 1994-2008  

Science.gov (United States)

Estonia, Latvia, and Lithuania belong to the margin of the Fennoscandian postglacial rebound (PGR) area. Vertical rates predicted by PGR models are in the range 0 to +3 mm/yr. Our first absolute gravity campaigns in the area were performed with the JILAg-5 gravimeter in 1994-1995 when three stations were measured in each country. All three stations in Lithuania were repeated with the JILAg-5 in 2002 and one of them (Vilnius) with the FG5#221 gravimeter in 2007. In Latvia one station (Riga) was remeasured with the FG5#101 and FG5#107 (D. Stizza, NIMA) in 1986 and with the FG5#221 in 2007. In Estonia two of the stations (Suurupi and Töravere) were remeasured with the FG5#220 in 2007 and with the FG5#221 in 2008, the third (Kuressaare) was only remeasured in 2008 with the FG5#221. This amounts to seven repeated stations with time spans of 8-13 years. In interpreting gravity change, special attention must be paid to subsurface water storage, as (due to inaccessibility of crystalline bedrock) many stations are on thick sediments, the repeat measurements were partly made in different seasons, and in some cases there is evidence of strong interannual variation in hydrology. We discuss the constraints to PGR implied by the observed gravity change and compare it with PGR models and with available observations of vertical motion.

Mäkinen, J.; Bilker-Koivula, M.; Falk, R.; Gitlein, O.; Kaminskis, J.; Lapushka, K.; Oja, T.; Paršeliunas, E.; Petroškevi?ius, P.; Timmen, L.

2009-04-01

 
 
 
 
301

Absolute temperature measurements using a two-color QWIP focal plane array  

Science.gov (United States)

The infrared photon flux emitted by an object depends not only on its temperature but also on a proportionality factor referred to as its emissivity. Since the latter parameter is usually not known quantitatively a priori, any temperature determination based on single-band radiometric measurements suffers from an inherent uncertainty. Recording photon fluxes in two separate spectral bands can in principle circumvent this limitation. The technique amounts to solving a system of two equations in two unknowns, namely, temperature and emissivity. The temperature derived in this manner can be considered absolute in the sense that it is independent of the emissivity, as long as that emissivity is the same in both bands. QmagiQ has previously developed a 320x256 midwave/longwave staring focal plane array which has been packaged into a dual-band laboratory camera. The camera in question constitutes a natural tool to generate simultaneous and independent emissivity maps and temperature maps of entire two-dimensional scenes, rather than at a single point on an object of interest. We describe a series of measurements we have performed on a variety of targets of different emissivities and temperatures. We examine various factors that affect the accuracy of the technique. They include the influence of the ambient radiation reflected off the target, which must be properly accounted for and subtracted from the collected signal in order to lead to the true target temperature. We also quantify the consequences of spectrally varying emissivities.

Bundas, Jason; Dennis, Richard; Patnaude, Kelly; Burrows, Douglas; Faska, Ross; Sundaram, Mani; Reisinger, Axel; Manitakos, Dan

2010-04-01

302

SQUID-based setup for the absolute measurement of the Earth’s magnetic field  

International Nuclear Information System (INIS)

We present a configuration of LTS dc SQUID magnetometers that is suited for an absolute measurement of the vector components of the Earth’s magnetic field with a white noise level of about 6 fT Hz?1/2. Due to its periodic voltage–flux characteristic, a SQUID’s output voltage generally corresponds to a set of equidistant fluxes or magnetic field strengths. To resolve this ambiguity, we introduce a configuration of coplanar SQUIDs integrated on a single chip, which exhibit effective areas differing by several orders of magnitude. The set of possible magnetic field strengths matching the output voltages of these SQUIDs is thereby significantly reduced and especially unique for magnetic field strengths less than a certain threshold value of about 10 ?T in our current implementation. The SQUIDs are realized with 0.8 ?m cross-type Josephson junctions that withstand high background fields of up to 3.9 mT during cool down and operation. A first one-dimensional experimental implementation successfully measured the modulation of the magnetic field component perpendicular to the sensor surface with amplitudes exceeding 50 ?T. The overall dynamic range of the SQUID magnetometer system achieves 190 dB. (paper)

303

Measurement of the Absolute Branching Fractions for $D^-_s\\!\\rightarrow\\!\\ell^-\\bar{\  

Energy Technology Data Exchange (ETDEWEB)

The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -}DKXD*{sub s}{sup -}, where D*{sub s}{sup -} {yields} D{sub s}{sup -}{gamma} and X represents additional pions from fragmentation. The D{sub s}{sup -} {yields} {ell}{sup 0}{nu}{sub {ell}} events are detected by full or partial reconstruction of the recoiling system DKX{gamma}{ell}. The branching fraction measurements are combined to determine the D{sub s}{sup -} decay constant f{sub D{sub s}} = (258.6 {+-} 6.4 {+-} 7.5) MeV, where the first uncertainty is statistical and the second is systematic.

del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, David Nathan; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U.; /more authors..

2010-10-27

304

Standardisation of 125Sb and 154Eu, and measurement of absolute gamma-ray emission probabilities  

International Nuclear Information System (INIS)

A method has been devised to separate 125Sb from its short-lived daughter 125mTe. This technique was based on the repeated use of columns of anion exchange resin and supplemented by chemical procedures chosen to avoid any steps involving evaporation, which in initial trials gave severe problems due to the volatility of the antimony. Standardisation by 4??-? coincidence counting was carried out within a few days of the separation, allowing for the daughter which grows in at about 0.25% per day. Beta counting efficiencies, as measured by the ratio of coincidence to gamma count rates, of up to 90% and 95% respectively were obtained for the two gamma-ray energy windows used. The ingrowth was monitored over a period of one month by gamma-ray spectrometry, using the weak 109 keV gamma-ray of 125mTe, to check the original separation. Samples of 154Eu were produced by neutron irradiation of high purity 153Eu, which was obtained by passing inactive europium through the NPL isotope separator. A solution of the 154Eu was standardised by coincidence counting, again using two gamma-ray energy windows, to give efficiencies of 96% and 98%. Absolute gamma-ray emission probabilities were measured for both nuclides using a germanium spectrometer calibrated with a range of nuclides of known activities and gamma-ray emissions. Sources were positioned 55 cm from the detector to ensure that real summing effects were negligible. (orig.)

305

Measurement of the absolute energy level and hyperfine structure of the 87Rb 4D5/2 state.  

Science.gov (United States)

We have measured the absolute frequency of the excited state transition 5P(3/2)-4D(5/2) in a (87)Rb atom with a femtosecond frequency comb, utilizing the recently developed spectroscopic technique of the double resonance optical pumping method. The absolute energy level of the 4D(5/2) state is determined by measuring the absolute frequency of the 5S(1/2)-5P(3/2) transition simultaneously. The hyperfine structure constants of the 4D(5/2) state are obtained by using the measured frequency. The magnetic dipole constant, A, is determined to be (-16.747+/-0.010) MHz with an uncertainty reduced 60-fold compared with a previous result. The electric quadrupole constant, B, is determined, for what is to our knowledge the first time, to be (4.149+/-0.059) MHz. PMID:17909581

Lee, Won-Kyu; Seb Moon, Han; Suhng Suh, Ho

2007-10-01

306

Absolute measurements of total-body calcium using prompt gamma neutron analysis and internal chlorine standardization: results in renal patients.  

Science.gov (United States)

Measurement of total-body calcium (TBCa) is important in the study of several medical conditions. Neutron activation analysis (NAA) is sufficiently precise for serial measurements, but in order to provide single, absolute determinations of TBCa, it requires a correction for body habitus. A method is described for the absolute determination of TBCa by comparing the total-body chlorine, obtained by NAA, with that obtained by stable bromine dilution. The method is applied to a group of thirty patients who had been treated for chronic renal failure, and significant differences are found between measured values of TBCa and those predicted for 'normal' healthy subjects. The overall experimental error in the absolute determination of TBCa is estimated to be 8%, for a dose equivalent of 3.1 mSv (based on skin dose, and a quality factor of 10 for neutrons). PMID:8161962

Evans, C J; Thomas, D W; Ryde, S J; Williams, A J

1994-02-01

307

Absolute coverage measurement of adsorbed CO and D2 on platinum  

International Nuclear Information System (INIS)

Nuclear microanalysis, in conjunction with MeV 4He scattering, LEED, and Auger spectroscopy, is being applied to investigate the adsorption behaviour of various gases on monocrystalline platinum surfaces. Using an anodized Ta2O5 film of known thickness as the primary standard, we have calibrated the 16O(d,p1)17O reaction for analysing the surface coverage of oxygen in our UHV system with an absolute accuracy of +- 2%. Suitable secondary standards for calibrating the 12C(d,p)13C and D(3He,p)4He reactions have been prepared by cooling a clean metal target to 20 K and condensing on it a fairly thick (approx. 100 nm) film of either CO2 or D2O ice. The 16O(d,p1)17O reaction plus the Ta2O5 standard is then used to determine the absolute number of CO2 or D2O molecules (and hence the number of C or D atoms) in the frozen film to +- 3%. For saturation coverage of the Pt(100) surface with CO molecules at 185 K, preliminary values of (0.85 +- 0.06) x 1015O atoms cm-2 and (0.89 +- 0.04) x 1015 C atoms cm-2 have been obtained. Similar measurements on Pt(111) gave a saturation CO coverage corresponding to (0.69 +- 0.05)x 1015O atoms cm-2 and (0.79 +- 0.03) x 1015 C atoms cm-2. In both casesup> C atoms cm-2. In both cases, the 16O(d,p1)17O analysis gives a slightly smaller value than the 12C(d, p)13C result. In another series of runs, the D(3He,p)4He reaction has been used to measure the surface coverage of hydrogen on Pt(111). A 10 min exposure to 1.3 x 10-4 Pa of molecular D2 gas at 185 K produces a deuterium coverage of (1.10 +- 0.05) x 1015 atoms cm-2. (orig.)

308

Geometry Optimization Of Marinelli Sample In Environmental Radioactivity Measurement  

International Nuclear Information System (INIS)

The problem of geometry optimization in environmental radioactivity determination has been studied by many scientists in the world. However, up to now, there have been not any published articles which studied optimum sample geometry in any given volumes. In this work, the simulation program MCNP was used to build the detection efficiency analytical formulas which can be used to calculate optimized geometries of Marinelli beaker in environmental radioactivity measurement. The geometry optimization was carried out with the sample volumes from 10 ml to 450 ml and the gamma-ray energy from 60 keV to 2 MeV. These optimized geometries give the highest detection efficiencies corresponding to given volumes. The goal of our study is to improve the limitation in low-level radioactivity measurement of environmental samples. (author)

309

Airborne measurement of radioactivity by learjet 35A  

Energy Technology Data Exchange (ETDEWEB)

In case of a radioactive emergency radioactive plumes may be expected in heights up to the tropopause. For this reason aircraft measurements are necessary as a supplement to ground-based measuring sites. The authors present an aircraft type learjet 35A used for localizing and analyzing radioactive contaminated air masses up to 12,000 m. The aircraft is equipped with an isokinetic high-volume sampler to collect aerosols on filters outside the pressurized cabin and an onboard gamma spectrometry system with a high purity germanium detector to analyze the filters during flight as well as a dose ratemeter, a radon daughter monitor and equipment to collect gaseous iodine and noble gases. The meteorological parameters temperature, atmospheric pressure, relative humidity, wind speed and wind direction are determined as well. Resulting data are transmitted from the plane to the headquarter of the German Meteorological Service (Deutscher Wetterdienst, DWD) and used for verifying the prognosis. (orig.)

Dyck, W.; Brust, H.; Dalheimer, A.; Steinkopff, T. [Deutscher Wetterdienst, Offenbach a.M. (Germany)

2004-11-01

310

Airborne measurement of radioactivity by learjet 35A  

International Nuclear Information System (INIS)

In case of a radioactive emergency radioactive plumes may be expected in heights up to the tropopause. For this reason aircraft measurements are necessary as a supplement to ground-based measuring sites. The authors present an aircraft type learjet 35A used for localizing and analyzing radioactive contaminated air masses up to 12,000 m. The aircraft is equipped with an isokinetic high-volume sampler to collect aerosols on filters outside the pressurized cabin and an onboard gamma spectrometry system with a high purity germanium detector to analyze the filters during flight as well as a dose ratemeter, a radon daughter monitor and equipment to collect gaseous iodine and noble gases. The meteorological parameters temperature, atmospheric pressure, relative humidity, wind speed and wind direction are determined as well. Resulting data are transmitted from the plane to the headquarter of the German Meteorological Service (Deutscher Wetterdienst, DWD) and used for verifying the prognosis. (orig.)

311

Marine radioactivity measurements with liquid scintillation spectrometers  

International Nuclear Information System (INIS)

Liquid Scintillation Spectrometry (LSS) has now become the most widespread method for quantitative analytical measurement of low levels of ?-emitting radionuclides like 3H and 14C. The high efficiency resulting from the latest development in LSS makes this technique not only appropriate but also enables direct measurement in environmental samples without excessive preparation. The introduction of several new cocktails based on solvents with a high flashpoint containing surfactants and having a high degree of aqueous sample compatibility has also contributed to the simplification of procedures

312

Measuring the absorbed radioactivity during a flight  

International Nuclear Information System (INIS)

This paper presents the new system SIEVERT developed by the General Direction of the Civil Aviation (DGAC) to measure the radiations doses absorbed from cosmic radiation. The system is available on the Internet site: www.sievert-system.org. (A.L.B.)

313

Krypton-85 and other airborne radioactivity measurements throughout Ireland  

International Nuclear Information System (INIS)

In compliance with articles 35 and 36 of the EURATOM Treaty, the Radiological Protection Institute of Ireland (RPII) undertakes a comprehensive programme of radioactivity monitoring in the Irish terrestrial environment. Radioactivity is present in the terrestrial environment due to natural processes, the testing of nuclear weapons in the atmosphere, accidents such as the Chernobyl accident and the routine discharge of radionuclides from nuclear installations. The RPII monitors airborne radioactivity concentrations at ten stations throughout Ireland, of which, nine are equipped with low volume particulate samplers and one, in Dublin, with a high volume particulate sampler. The low volume particulate samples are assessed for total beta activity and high volume samples for gamma emitting radionuclides such as caesium-137 and beryllium-7. In addition, air sampled at the RPII laboratory in Dublin, is monitored for krypton-85, a radioactive noble gas, released into the environment primarily as a result of the reprocessing of nuclear fuel at installations such as Sellafield in the UK and La Hague in France. Since the inception of the krypton measurements in 1993 a trend of increasing atmospheric concentrations has been observed. The results of the krypton-85 monitoring, as well as the airborne radioactivity concentration measurements, will be presented and discussed in this paper. (author)

314

Radioactivity measurements of the HMI after the Chernobyl reactor accident  

International Nuclear Information System (INIS)

The report explains the methods applied and the data measured by the HMI campaign. The material is presented so as to be of interest also to readers who in general are not concerned with aspects of radiation protection. The data measured refer to the local dose rate and to radioactivity in the environment (air, rain, surface waters, soil, food, mother's milk. Also, results of measurements of samples from Eastern Europe are given. (orig./HP)

315

Instrument measuring the radioactive contamination of a product  

International Nuclear Information System (INIS)

The measuring instrument includes a scintillating crystal detecting gamma rays emitted by radionuclides (iodine, cesium or cobalt). Photons are converted by a photodiode into electric charges which are converted in voltage pulses and filtered for the different frequencies. Pulse counting the different frequency ranges and deconvolution by electronic circuits measure the contamination produced by each radionuclide. The instrument is compact, light, cheap and specially designed for food contamination measurement by the public, after a radioactive accident

316

Measurements and Monte Carlo calculations to determine the absolute detector response of radiochromic film for brachytherapy dosimetry  

International Nuclear Information System (INIS)

GafChromic (MD-55-2) radiochromic film has become increasingly popular for medical applications and has proven to be useful for brachytherapy dosimetry. To measure the absolute dose near a brachytherapy source, the response of the proposed detector in the measurement conditions relative to the response of the detector in calibration conditions must be known. MD-55-2 radiochromic film has been exposed in four different photon beams, a 30 and 40 kVp tungsten anode x-ray beam, a 75 kVp orthovoltage therapy beam, and a 60Co teletherapy beam to measure the relative detector response. These measurements were combined with coupled photon/electron Monte Carlo transport calculations to determine the absolute detector response. The Los Alamos National Laboratory Monte Carlo transport code MCNP4B2 was used. The measured relative response of this batch of MD-55-2 film varies from 8.79 mOD/Gy, measured for the 60Co beam, by as much as 42% for the low-energy x-ray beams. However, the absolute detector response varies from 4.32 mOD/Gy for the 60Co beam by, at most, only 6.3%. In this work we demonstrate that the absolute detector response of MD-55-2 radiochromic film is a constant and independent of beam quality. Further, this work shows that MCNP4B2 accurately simulates the energy response and geometry artifacts of the radiochromic film

317

Absolute femtosecond measurements of Auger recombination dynamics in lead sulfide quantum dots  

Directory of Open Access Journals (Sweden)

Full Text Available Multiphoton excitation of hot carriers generates multiexcitons that are probed as a function of the absolute number of photons absorbed. Standard assumptions of Auger recombination analyses fail for an average of 2 excitations.

Jonas D.M.

2013-03-01

318

Study of a 4??-? coincidence system for absolute radionuclide activity measurement using plastic scintillators  

International Nuclear Information System (INIS)

The present work was intended to study a coincidence system 4?(PS)?-? for absolute activity measurement using plastic scintillators in 4? geometry. Along with experiments on the coincidence system, simulations were also performed applying the Monte Carlo Method, by means of codes PENELOPE and ESQUEMA. These simulations were performed in order to calculate the extrapolation curve of the coincidence system 4?(PS)?-? and compare it to experimental data. A new geometry was proposed to the coincidence system adding up a second photomultiplier tube to the previous system for improving light collection from the plastic scintillator, as this system presented limitations in the minimum detected energy due to the presence of electronic noise and low gain. The results show that an improvement in the signal-to-noise ratio was obtained, as well as in the minimum detected energy. Moreover, there was an increase in the detection efficiency. With these modifications, it is now possible to calibrate radionuclides which emit low energy electrons or X-rays, increasing the number of radionuclides that can be standardized with this type of system.(author)

319

Prediction of absolute concentrations of elements from SR XRF scan measurements of natural wet sediments  

Energy Technology Data Exchange (ETDEWEB)

We report a method to predict absolute concentrations of elements in natural wet sediments (cores) from their SR XRF scan measurements. This prediction is problematic because: (i) relationship between fluorescent intensity and element concentrations is strongly biased by variability of pore water content in thick samples; (ii) thickness and mass of fluorescent layers are likewise variable; and (iii) spectral responses are perturbed by interference of elements. It is suggested to overcome these difficulties using an adapted algorithm of fundamental parameters. The mathematical model based on this algorithm accounts for two events of photon/matter interaction. Element concentrations are estimated using reference samples and the internal standard procedure, both with correction of interference effects. The pore water content is inferred from its correlation with the Rayleigh (coherent)/Compton (incoherent) scatter intensity ratio. Sediment density is found from water content by a reliable sedimentological law. Normalization to Compton scattering accounts for the irradiated mass of wet sediment controlled by porosity and sampling-related core disturbance. The mathematical model also includes these scattering variations related to lithology, water content, and density of samples. The new method was applied to SR XRF scans of cores from Lake Baikal and Lake Teletskoye to predict concentrations of 20 elements (K-Ba, REE, Th, U). Tests against ICP-MS and conventional SR XRF (with traditional pretreatment of samples) show good agreement and stability of SR XRF scanning. Neglect of the disturbing effects may cause errors up to 30-150%.

Phedorin, M.A. [Limnological Institute, Ulan-Batorskaya str., 3, Russian Academy of Science, Siberian Branch, Irkutsk, 664033 (Russian Federation)]. E-mail: mikeph@mail.ru; Goldberg, E.L. [Limnological Institute, Ulan-Batorskaya str., 3, Russian Academy of Science, Siberian Branch, Irkutsk, 664033 (Russian Federation)

2005-05-01

320

Methods for Measuring Sand Transport Using Radioactive Tracers  

International Nuclear Information System (INIS)

Radioactive glass particles are sometimes used in the field for investigating the behaviour of sand and silt. Experiments have been performed in a flume with a rippled sand bed to compare the rate of movement of sand and glass particles of the same size and density. Several methods of measuring sand transport in the flume using radioactive tracers are described and compared. Two of these methods have been investigated in a series of tests; the first, usually termed the space integration method, involves the measurement of the spatial distribution of particles from a strip of the bed after various times; the second, referred to as the time integration method, requires the measurement of the passage of the tracer in time at a station downstream. These methods have been used to measure the velocity of several size fractions in a sand mixture. The practical difficulties of applying these methods to measurements in the field are briefly examined. (author)

 
 
 
 
321

IAEA intercomparison results on measurement of radioactivity in environmental samples  

International Nuclear Information System (INIS)

The author describes the intercomparison results on radioactivity measurements of radioactive nuclides in ALMERA-SOIL-1 (soil) and ALMERA-SED-1 (lake sediment) environmental samples. The intercomparison was organized by International Atomic Energy Agency (IAEA). The measurements of activities were completed with a HPGe low background anti-compton Gamma-spectrometer using the methods of relative comparison and efficiency curve. Nine nuclides in ALMERA-SOIL-1 and six nuclides in AlMERA-SED-1 were measured respectively. The measured values of the activity concentration agreed with the overall mean within the range of experimental uncertainties except for the activity of 60Co in ALMERA-SOIL-1 sample. It also discusses the reasons why some nuclides were not detected and few measured values were divergent

322

IAEA-MEL's AQCS programme for marine radioactivity measurements  

International Nuclear Information System (INIS)

The main objectives of the IAEA-MEL's Analytical Quality Control Services (AQCS) for marine radioactivity measurements are discussed and future plans for the organization of intercomparison exercises and the production of certified reference materials are presented. The new developments should also include implementation of quality assurance programmes in Member States' laboratories, training in quality management and accreditation programmes. (author)

323

Measurement of natural radioactivity in construction materials with silicon detectors  

International Nuclear Information System (INIS)

The results of radioactive contamination measurements of the construction materials most commonly used in the process of building the apparatus for low-level counting are discussed. They were obtained using an apparatus for low-level counting with four semiconductor detectors. (author)

324

Measuring system for radioactivity of labelled biopolymers  

International Nuclear Information System (INIS)

The apparatus incorporates a steel container for samples of biological biopolymers in conjunction with a co-precipitator, filtration unit and scintillator. An electrical drive is employed for stepwise movements of the system. A control unit is included for regulation of the degree of radio activity. The various reagents are contained in separate vessels. A vacuum pump is employed for the filtration process. The measuring cylinder is a hollow unit made of polyfluoroethylene with end surfaces of film of the same material. Carbon dioxide under presure is used as a control medium. (G.C.)

325

Measurement of nuclear cross sections using radioactive beams  

International Nuclear Information System (INIS)

One of the main applications of the production and use of nuclear radioactive beams is the measurement of nuclear cross sections. In this work is used a 6 He nuclear radioactive beam (? emitting with half life 806.7 ms) for the study of the reaction 6 + 209 Bi which could have several products. This investigation was realized in collaboration with the personnel of the Nuclear Structure laboratory at the University of Notre Dame (U.S.A.) and the National institute of Nuclear Research and CONACyT by Mexico. (Author)

326

Measurement of radioactive dust in high altitude air  

International Nuclear Information System (INIS)

The radioactivities of airborne dust in samples were measured. The samples had been collected at high altitude by the Japan Air Self-Defense Force from April 2006 to March 2007. The data were obtained for the gross beta activity, gamma nuclide determination and radiochemical analysis. It is shown that there is no appreciable difference between the activity levels of this time and ones of the year before. Seasonal variations are little pronounced. It is found that the radioactivity have been stable in the low level at high altitude. (author)

327

Measurement of absolute E2 transition strengths in 176W: Signatures for a rapid shape change  

Science.gov (United States)

The X(5) symmetry describes nuclei at the critical point of the shape phase transition from axially deformed rotor nuclei to spherical vibrators. 150Nd, 152Sm, and 154Gd were the first nuclei where the predicted charateristics of the X(5) symmetry were observed. Later it was shown that also 176,178,180Os can be successfully described with the X(5) symmetry. In the close vicinity of shape phase transitions one expects strongly changing nuclear shapes. In the X(5) region around A = 150 this was observed for nuclei with different neutron numbers, whereas in the X(5) region around A = 180 this is to be expected for different proton numbers. The aim of the work presented here is the confirmation of a rapid shape change for nuclei close to 178Os. Besides the knowledge on the level scheme of the nuclei of interest, especially absolute E2 transition strengths are crucial for the interpretation of nuclear structure. Prolate deformation is expected for 176W. Thus we performed a recoil distance Doppler shift (RDDS) measurement on 176W to measure E2 transition strengths from level lifetimes. The experiment was performed at the Cologne FN TANDEM accelerator with the Cologne coincidence plunger with the reaction 169Dy(16O,4n)176W and a beam energy of 80 MeV. We will present our experimental results and relate them to data on the neighboring nuclei 178Os and 182Pt. The results will be discussed in the framework of nuclear shape transitions in this mass region and compared to calculations with both the Interacting Boson Model (IBM) and the GCM.

Fransen, Ch.; Dewald, A.; Friessner, G.; Hackstein, M.; Jolie, J.; Möller, O.; Pissulla, T.; Rother, W.; Zell, K.-O.

2011-10-01

328

Radionuclide absolute left ventricular volumes during upright exercise: Validation in normal subjects by simultaneous hemodynamic measurements  

International Nuclear Information System (INIS)

A nongeometric radionuclide technique for the determination of absolute left ventricular volumes was validated during exercise in nine normal subjects. Simultaneous reference stroke volume and cardiac output measurements were obtained by the Fick method. The reference left ventricular volumes were calculated by combining the Fick stroke volume and the isotopic ejection fraction. Data were collected at rest in the supine and upright positions and during 600 upright exercise, at three levels of increasing severity. At rest, from supine to upright position, the reference end-diastolic volume decreased significantly from 182+-24 ml to 154+-21 ml (mean +-SD,P<0.005); during upright exercise of low intensity, end diastolic volume increased to 176+-24 ml (P<0.05); at maximal exercise, end-diastolic volume was not different from the resting value in upright position. The end-systolic volume gradually decreased at rest from 67+-11 ml in the supine position to 54+-8 ml in the upright position (P<0.05) and to 32+-7 ml at maximal exercise (P<0.005). Compared with these reference data, the scintigraphic measurements were significantly lower on average by 23% for stroke volume, 21% for cardiac output, 22% for end-diastolic volume, and 23% for end-systolic volume. The overall changes in stroke volume (P<0.05) and end-systolic volume (P<0.001) occurring at rest during exercise were correctly detected by the scintigraphic method but the smaller changes in end-diastolic volume (less than 15%) were not (P<0.15) because they were within the range of the precision of the technique. If subtle changes in left ventricular volume are to be quantitated, attempts should be made to reduce the random variability of the scintigraphic method. (orig.)

329

Absolute frequency measurements of 85Rb nF7/2 Rydberg states using purely optical detection  

CERN Document Server

A three-step laser excitation scheme is used to make absolute frequency measurements of highly excited nF7/2 Rydberg states in 85Rb for principal quantum numbers n=33-100. This work demonstrates the first absolute frequency measurements of rubidium Rydberg levels using a purely optical detection scheme. The Rydberg states are excited in a heated Rb vapour cell and Doppler free signals are detected via purely optical means. All of the frequency measurements are made using a wavemeter which is calibrated against a GPS disciplined self-referenced optical frequency comb. We find that the measured levels have a very high frequency stability, and are especially robust to electric fields. The apparatus has allowed measurements of the states to an accuracy of 8.0MHz. The new measurements are analysed by extracting the modified Rydberg-Ritz series parameters.

Johnson, L A M; Sanguinetti, B; Becker, Th; Varcoe, B T H

2010-01-01

330

ROKO-Database of the environmental radioactivity measurements in Slovenia  

International Nuclear Information System (INIS)

ROKO is the acronym of the Environmental Radioactivity in Slovenian language Radioaktivnost v OKOlju. Computer database ROKO contains data of all measurements of the radioactivity in the environment in Slovenia. Data about radioactivity in the environment have been collected in Slovenia more or less regularly since 1961 on. Most results are gathered in the form of paper reports. Slovenian Nuclear Safety Administration (SNSA) has initiated the project of transfer of all those data into the electronic form and making it available for easy research. The database is designed so, that it contains all records, relevant for any kind of analyses and for the transfer to the international data systems. By the end of the summer 2005 a major part of data from previous years have already been transferred into the database and the user interface software is under development. It will allow the users to examine individual data records, to plot time history graphs or geographical contour plots. (author)

331

Size distribution of atmospheric radioactive aerosols and its measurement  

International Nuclear Information System (INIS)

The variation of the size distribution of radioactive aerosols may cause a large fluctuation of lung dose caused by radon and its daughters. Since the information on the size distribution of radioactive aerosols in China is scanty, authors usually quote the recommended data by UNSCEAR (1988) to estimate the lung dose. In order to check whether the quoted data are reasonable and establish the method of measuring the size distribution of the aerosols, we carried out this study. The penetration curve can be bluffed by measuring the atmospheric radioactivity ratio for the different diffusion using the wire screen (165 meshes) type diffusion battery. The size distribution of atmospheric radioactive aerosols was calculated by ikebe anatical method. The size distribution for outdoors and indoors showed a geometric normal distribution. The arithmetic mean peak diameter for indoor and outdoor size distribution were (0.20 +- 0.09) ?m and (0.27 +- 0.11) ?m, respectively. The correlation between the size distribution and the concentrations of radon and metrological factors was not significant. The measured result for indoors is the same as the recommended data by UNSCEAR (1988), while the result for outdoors is slightly higher than the recommended data, but it is similar to that reported by Jacobi. It is basically feasible for Fujian Province to estimate lung dose using the recommended data by UNSCEAR (1988). Further studies are needed to extend this conclusion nationwide extend this conclusion nationwide

332

Portable measuring equipment for radioactive contamination  

International Nuclear Information System (INIS)

The measuring device is composed of a mobile probe with electrical evaluating equipment and a large-area counter. The counter processes two opposite guide grooves into which the slide bars of a base part belonging to the probe can be pushed. This base part, attached, e.g., to the wall of a laboratory room, has coupler links on one side contacting counter links mounted on the probe when this one is pushed on to the base part. In this way a current connection, a stop mounting of both parts on one another, and a gas connection for the large-area counter are created. Charging of the supply accumulators for the probe as well as washing of stop mounting essentially consists of a spring-supported notched ball and a saw-footh shaped gliding plane which is summing up the ball when the probe is pushed in and then abruptly releasing the ball again. The ball is not released, however, until the gas-tight and electrical work connection has been made. (DG)

333

Portable measuring equipment for radioactive contamination  

International Nuclear Information System (INIS)

The measuring instrument is composed of a probe part with analyzing electronics and a large-area counter. The counter tube is replaceably mounted on the casing of the analyzing electronics. It also has two guide grooves opposite to one another in which the slide bars of a base part belonging to the probe part can be inserted. This basic member which may e.g. be fastened onto the wall of a laboratory room has coupler links on one side, which come into contact with corresponding elements on the probe part if this one is pushed over the base part. These are, among others, a power supply, a click-stop device keeping both parts together and a gas supply for the large-ared counter. Charging of the power supply accumulators of the probe part as well as purging of the counting tube is therefore made possible in this state of interconnection. The click-stop device essentially consists of a spring-borne stop ball and a saw-tooth shaped gliding surface running up the stop ball if the probe part is inserted then releasing it again promptly. (DG)

334

Recent developments at Saclay for measuring absolute cross sections of reactions between heavy ions by in-beam gamma techniques  

International Nuclear Information System (INIS)

The potentiality of the in-beam gamma techniques to measure absolute cross sections in the fusion-evaporation domain is discussed. These techniques have been used (with Ge(Li) detectors) for more than one decade, but in view of the considerable progress which has been achieved in the last years, it seems worth while to reconsider to day their merits and limitations

335

Absolute light yield measurements on SrF$_{2}$ and BaF$_{2}$ doped with rare earth ions  

CERN Document Server

Results of absolute light output measurements on strontium and barium fluoride doped with PrF$_3$ and CeF$_3$ are presented and compared with scintillators having well-known light output (NaI-Tl, CsI-Tl, BGO). For pure SrF$_2$ crystal we obtain a value of about 28600 photons/MeV.

Shendrik, Roman

2013-01-01

336

Measurement and analysis of radioactive substances; Mesure et analyse de substances radioactives  

Energy Technology Data Exchange (ETDEWEB)

Here are gathered the abstracts presented to the 3. summer university of the year 2001 whose main themes were the destructive (5 conferences) and nondestructive (8 conferences) analyses applied to nuclear industry. The points of view of different organisms (as DSIN: Directorate for the Safety of Nuclear Installations, IPSN: Institute of Nuclear Protection and Safety, OPRI: Office of Protection against Ionizing Radiations, TUI: Institute for Transuranium Elements, COGEMA, EDF: Electric Utilities, ANDRA: French National Agency for Radioactive Waste Management, CRLC Val d'Aurelle, France) concerning the needs involved in nuclear facilities control, the methods of radionuclide speciation in use internationally, the measurements and analyses of radioactive substances are given too as well as some general concepts concerning 1)the laser-matter interaction 2)the ions production 3)the quality applied to the measurements and analyses 4)the standard in activity metrology. (O.M.)

NONE

2001-07-01

337

Fieldwork measuring methods of NPP background investigation of environmental radioactivity  

International Nuclear Information System (INIS)

Aimed at NPP background investigation of environmental radioactivity, this paper first points out the investigation objectives and content, and proposes an efficient and practical fieldwork measuring methods by combining relevant standards and natural and social environment condition of the investigation area, finally some critical issues such as samples collecting and setting measuring parameters are also solved for the successful implementation of similar follow-up projects. (authors)

338

Radioactivity measurement for emergency or post-accident situations  

International Nuclear Information System (INIS)

Specific objectives have to be achieved by radioactivity measurements during emergency or post-accident situations, which are different from those in normal situation. At the beginning of a nuclear emergency, few radioactivity data will be available, mainly from automatic monitoring systems implemented on the site or in its surrounding. Progressively, measurement programmes will be performed, in priority to get information on dose rate, atmospheric radionuclides and surface activities. In order to avoid excessive exposure of the measure teams, these programmes should be optimized. During early post-accident phase, different types of measurements will be done, following two main objectives: 1) to improve the assessment of the environmental contamination and people exposure; 2) for control purpose, to check the contamination of urban places, foodstuff and other products, compared to specific reference levels. The samples measurement in laboratories would be a challenge: usually, the laboratories involved in routine monitoring have to deal with very low level of radioactivity and a poor diversity of artificial radionuclides; after a reactor accident, the environmental samples to be measured would be more active and with a mixture of radionuclides (mainly with short or middle half-life) difficult to be characterized. So theses laboratories have to be trained and organised before any severe accident. (author)

339

Radioactivity measurements in Egyptian Phosphate Mines and Their Significance As a Source of Hazardous Radioactive Waste  

International Nuclear Information System (INIS)

Phosphate mines that may contain radioactive traces in the composition of their ores represent source of hazardous radioactive waste in the environment. Radioactivity measurements have been conducted in nine underground phosphate mines in the Egyptian Eastern Desert in order to estimate the occupational radiation exposure of mine workers in those mining sites. Measurements were carried out of airborne radon and its short- lived decay products (progeny) and thoron progeny, as well as radiation from mines walls, ceilings and floors. Conventional, well established techniques, methods and instrumentation were used to make these measurements. Comparison of experimental data and theoretical predictions showed partial agreement between these two sets of data. This result is partly attributed to the complex layout of these mines, which causes undesirable ventilation conditions, such as recirculation airflow patterns, which could not be adequately identified or quantified. The radiation data obtained were used to estimate the maximum Annual Dose (MAD), and other important occupational radiation exposure variables. These calculations indicate that in eight out of the nine mines surveyed, the MAD exceeded (by a factor of up to 7) the maximum recommended level by ICRP 60. Numbers of suggestions are made in order to reduce the MAD in the affected mines. This study could help in the estimation of the environmental impact of these mine operations on the environment

340

Radioactivity and main ?-ray emission probability measurements of short half-Life nuclide 142La  

International Nuclear Information System (INIS)

The radioactivity and the absolute gamma emission probability for the 641 keV main gamma ray of the short half nuclide 142La were measured by DCC on a 4??-4?? and a 4??-4?? coincidence counting devices,and the standard uncertainty for the radioactivity measurement result is 0.46%, the emission probability of the 641 keV gamma ray is 0.473±0.005, which is only 0.24% lower than the data 0.474±0.005 proposed by the Table of Isotopes, 8th edition. The relative emission probabilities of the other main gamma rays were measured by another HPGe gamma spectrometer, which relative efficiency is above 60%, the measurement results are good. The half life of 142La was calculated to be (91.0±0.7)min, which has a lower deviation of 0.2% than (91.1±0.5)min proposed by the Table of Isotopes, 8th edition. (authors)

 
 
 
 
341

Evaluation of uncertainty and detection limits in radioactivity measurements  

Energy Technology Data Exchange (ETDEWEB)

The uncertainty associated with the assessment of the radioactive content of any sample depends on the net counting rate registered during the measuring process and on the different weighting factors needed to transform this counting rate into activity, activity per unit mass or activity concentration. This work analyses the standard uncertainties in these weighting factors as well as their contribution to the uncertainty in the activity reported for three typical determinations for environmental radioactivity measurements in the laboratory. It also studies the corresponding characteristic limits and their dependence on the standard uncertainty related to those weighting factors, offering an analysis of the effectiveness of the simplified characteristic limits as evaluated by various measuring software and laboratories.

Herranz, M. [Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Escuela Tecnica Superior de Ingenieria de Bilbao, Alda. Urquijo, s/n, 48013 Bilbao (Spain); Idoeta, R. [Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Escuela Tecnica Superior de Ingenieria de Bilbao, Alda. Urquijo, s/n, 48013 Bilbao (Spain)], E-mail: raquel.idoeta@ehu.es; Legarda, F. [Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Escuela Tecnica Superior de Ingenieria de Bilbao, Alda. Urquijo, s/n, 48013 Bilbao (Spain)

2008-10-01

342

Measurement of absolute fluorescence quantum yield of basic Fuchsin solution using a dual-beam thermal lens technique.  

Science.gov (United States)

The dual beam thermal lens technique is an effective method for the measurement of fluorescence quantum yield of dye solutions. The concentration-dependent quantum yield of a novel dye of triaminotriphenylmethane family in ethanol is studied using this technique. The absolute fluorescence quantum yield is measured and is observed that the reduction in the quantum yield is due to the non-radiative relaxation of the absorbed energy. PMID:24610515

Pathrose, Bini; Nampoori, V P N; Radhakrishnan, P; Mujeeb, A

2014-05-01

343

Time-of-flight facility for the absolute measurement of the beam energy of a medium-energy cyclotron  

International Nuclear Information System (INIS)

A method for measuring the energy of a medium-energy cyclotron is presented. It is based on a single detector which simultaneously detects gamma rays from two spatially separated targets. The method is absolute depending upon the cyclotron or local oscillator frequency and distance measurements. It is applicable to the variety of beam energies and particles from a variable energy cyclotron in the medium-energy range. (orig.)

344

Measurement of absolute left ventricular volume from gated blood pool studies  

International Nuclear Information System (INIS)

1 angiographic + 1ml); the standard error of the estimate as 3 ml. The method permits direct determination of absolute left ventricular volume without assumptions about the shape of the ventricle or the necessity of using regression equations to convert volume ''units'' to true volume

345

Specialized and technical advancement of the BFS radioactivity measurement network  

International Nuclear Information System (INIS)

After a short report on the general structural development of the BfS radioactivity measurement network, some specialized and technical advancements are presented which aim at qualitative improvements of the measuring results and at an acceleration of the data transfer in case of a nuclear event: In an intensive operation phase the measuring data are collected from the measuring posts and offered to decision makers in a cadence of 10 minutes now instead of 2 hours before. In the surroundings of nuclear plants the BfS radioactivity measurement network cooperates with the nuclear plant remote monitoring systems of the Laender with the effect that both networks complement each other. To ensure the comparability of the measured data of different measuring posts, criteria for the choice, documentation and evaluation of the site locations have been defined and correspondingly the posts have been evaluated. The properties of the gamma dose rate probes have been examined and a procedure for periodic examination of the environmental conditions close to the measuring posts has been developed and introduced. The development of a new generation of data collecting units enables different organisations to directly access the data from the measuring posts and furthermore these new data loggers provide improved techniques of data evaluation. (orig.)

346

Renewal of centralized radioactivity measurement system for radiation control  

International Nuclear Information System (INIS)

The centralized radioactivity measurement system has been used to carry out intensively measurements of a large number and variety of samples that are necessary for the control of radioactivity in the facilities of the JAERI Tokai Establishment and its environment. The operation of the system started in 1981, and presently the system processes more than 20,000 samples a year. However, the computers of the system have aged so much that the manufacturer's support and stable operation are no longer sure. Therefore, we renewed and restructured the computer system in 2003. A client-server system was adopted in the new system. The information of samples can be registered through the intranet. The clients can also confirm the progress of processing of their samples and browse the analytical results from their own computers. The renewed system can provide some convenience functions to the clients. (author)

347

Radiation protection measures for the handling of unsealed radioactive materials  

International Nuclear Information System (INIS)

The radiation protective medical measures are described which are required after contamination by radioactive materials or their incorporation. In the case of skin contamination, penetration by diffusion is explained and the maximum permissible value with regard to the various types of radiation is given. A detailed description of the decontamination measures including the necessary equipment follows. Indications for the treatment of injuries are given. In addition, incorporation due to inhalation, ingestion with intake through the skin are described, direct and indirect incorporation detection are explained, and the therapeutical possibilities and measures are gone into. (ORU/LH)

348

Nanometer-scale absolute laser ranging: exploiting a two-mode interference signal for high accuracy distance measurements  

Science.gov (United States)

Absolute distance measurement with accuracy below the micron scale is important in astronomical optical interferometry. We present here an absolute laser rangefinder which relies on the detection of a two mode interference signal. We exploit the specific signature of the signal to extract both the interferometric and synthetic phase measurements, leading to distance measurement with nanometric accuracy. A resolution of 100 pm has been achieved in 75?s with a relatively simple laser source. Amplitude to phase coupling in the detection chains turns out to be the largest source of systematic errors. A specific detection scheme is implemented, using optical demodulation of the microwave optical signal, to reduce amplitude-to-phase related systematic errors to below the required level.

Phung, D.-H.; Courde, C.; Alexandre, C.; Lintz, M.

2014-04-01

349

Radioactivity measurement in imported food and food related items  

International Nuclear Information System (INIS)

The Philippine Nuclear Research Institute (PNRI), formerly Philippine Atomic Energy Commission (PAEC) undertook the radioactivity monitoring of imported food and food-related products after the Chernobyl Plant accident in April 1986. Food samples were analyzed for 137Cs and 134Cs by gamma spectral method of analysis. This report deals with the measurement process and gives the result of the activity covering the period June 1986 to December 1987. (Auth.). 9 tabs., 7 figs., 4 refs

350

Measurements and evaluation of absolute emission probabilities for soft photons of 153Gd, 155Eu and 169Yb  

International Nuclear Information System (INIS)

Absolute emission probabilities of Kx- and ?-rays in the energy region 40-200 keV have been obtained for 153Gd and 155Eu using measurements of emission rates by Ge, Ge(Li) and Si(Li)-detectors and of activities by a 4??-? coincidence system. The main results of our measurements and evaluation of decay data of 153Gd and 155Eu were published in 1992 and 1994. Here new experimental data concerning soft photon radiation which were obtained with a new Si(Li) spectrometer calibrated on the basis of a generalized energy response functions are presented. For the 14.06 keV ?-ray in the decay of 153Gd a value of (0.029 ± 0.003) photons per 100 disintegrations has been measured. For 155Eu the absolute emission probabilities of Kx- and 26.5, 45.3, 58.0, 60.0 ?-rays have been measured using the Si(Li) (formerly only a Ge-detector was used). A re-evaluated value of the 153Gd half-life is reported. For 169Yb the evaluation of decay data has been carried out taking into account the results of the latest measurements of absolute emission probabilities of ?-rays with energies 63.12, 109.80, 130.52 and 197.96 keV. (author)

351

Ultra low radioactivity measurements at Modane underground Laboratory  

International Nuclear Information System (INIS)

We present in this paper the activities of the Laboratoire Souterrain de Modane, LSM, and in particular the activity related to Single-Event Rate Errors in semiconductors. The LSM is located in the middle of the Frejus tunnel under 1 800 m of rock. The rock coverage suppress the cosmic ray flux by about 2 millions with respect to the surface, thus, the LSM offers an excellent site for rare-event searches which would, if located on the surface, be overwhelmed by the cosmic-ray background. As semiconductor devices continue to be scaled down, the integrated circuits are sensitive to interactions with cosmic-ray particles on the surface (primarily atmospheric neutrons) or to interactions with alpha-particles produced in on-chip radioactive impurities disintegrations. The ultra-low background environment at LSM allows the measurement of extremely low radioactivity levels. The aim of the work presented in this paper is to assess the feasibility of the alpha-emission measurement in materials commonly used in integrated circuits, by means of ultra-low level gamma-spectrometry. An epoxy slab has been measured and the surface ?-emission has been deduced from the radioactive impurities level. The result is compared to the value obtained with an a- gas proportional counter. (authors)

352

Precise measurement of the absolute fluorescence yield of nitrogen in air. Consequences on the detection of ultra-high energy cosmic rays  

International Nuclear Information System (INIS)

The study of the energy spectrum of ultra-high energy cosmic rays (E > 1020 eV) requires to determine the energy with much more precision than what is currently achieved. The shower of particles created in the atmosphere can be detected either by sampling particle on the ground, or by detecting the fluorescence induced by the excitation of nitrogen by shower electrons. At present, the measurement of the fluorescence is the simplest and the most reliable method, since it does not call upon hadronic physics laws at extreme energies, a field still inaccessible to accelerators. The precise knowledge of the conversion factor between deposited energy and the number of fluorescence photons produced (the yield) is thus essential. Up to now, it has been determined with an accuracy of 15 % only. This main goal of this work is to measure this yield to better than 5 per cent. To do this, 1 MeV electrons from a radioactive source excite nitrogen of the air. The accuracy has been reached thanks to the implementation of a new method for the absolute calibration of the photomultipliers detecting the photons, to better than 2 per cent. The fluorescence yield, measured and normalized to 0.85 MeV, 760 mmHg and 15 Celsius degrees, is (4.23 ± 0.20) photons per meter, or (20.46 ± 0.98) photons per deposited MeV. In addition, and for the first time, the absolute fluorescence spectrum of nitrogen excited by a source has been measured with an optical grating spectrometer. (author

353

Measurements of environmental radiations and radioactivities in Toki, 5  

International Nuclear Information System (INIS)

The booklet carries six reports. The first report, titled 'Measurements of Environmental Radiation in 1986 and 1987', consists of two parts: 'A report of TLD Measurement of Environmental Radiations in the Toki Area' and 'Measurement of Environmental Radiations at the Higashiyama and Toki Sites'. Measurements of environmental radiations made at various points throughout the area are presented. The second report, titled 'Environmental Tritium Measurements in Toki Area', presents measurements of environmental tritium made at various points in the Toki area. The third study addresses the 'Radioactivity in Rain Associated with Chernobyl Nuclear Reactor Accident'. Rain is collected on the roof of the Institute of Plasma Physics, and gamma ray measurements are made with a germanium detector. The concentrations of radioactive fallout substances are analyzed. Then, the relations of the concentrations with the spatial dose rate is investigated. The fourth work deals with the 'Concept and Mutual Relation of Radiation-Related Quantities'. The fifth report outlines a 'System for Radiation Monitoring around Accelerator'. The sixth report describes some features of the National Lab. for High Energy Physics (KEK). (N.K.)

354

Measurements of environmental radiations and radioactivities in Toki, 6  

International Nuclear Information System (INIS)

The booklet carries five reports. The first one, titled 'A Study on Nuclear Fusion Environmental Safety in the Nagoya University, Institute of plasma physics', deals with the design and development of a radiation monitoring system and a tritium monitoring system. The second work, titled 'Measurement of Environmental Radiations', consists of two parts: 'A report on TLD Measurement of Environmental Radiations in the Toki Area' and 'TLD Measurement in Toki Area (1982-1988)'. Measurements of environmental radiations made at various points throughout the area are presented. The third study addresses 'Radioactivity in Rain Associated with Chernobyl Nuclear Reactor Accident'. Rain is collected on the roof of the Institute of Plasma Physics, and gamma ray measurements are made with a germanium detector. The concentrations of radioactive fallout substances are analyzed. Then, the relations of the concentrations with the spatial dose rate is investigated. The fourth report, titled 'Measurements of Environmental Tritium Concentration in the Toki Area', deals with measurements made at various points throughout the area are listed. The fifth and last report briefly outlines some features of the Kyoto University Plasma Physics Laboratory and the Osaka University Institute of Laser Engineering. (N.K.)

355

Airborne Measurement of Radioactivity by Learjet 35 A  

International Nuclear Information System (INIS)

Full text: The Deutscher Wetterdienst (DWD, German Meteorological Service) is responsible for surveillance of radioactivity in the atmosphere. In case of an accident, radioactive plumes may be expected in high heights up to the tropopause, however it depends on the type of accident. For this reason, aircraft measurements are necessary as a supplement to ground-based measuring sites, especially in case of non available details about the source of radioactive release and lack of details about the accident. The authors present an aircraft, type Learjet 35 A, used for localising radioactive contaminated air masses up to 33,000 feet (10,000 m) and the measurement of artificial radionuclides on aerosols. For this purpose the jet is equipped with an isokinetic high-volume sampler for collection of aerosols on filters outside the pressurised cabin and an onboard gamma spectrometry system with a high purity germanium detector to analyse the interchangeable, contaminated filters during flight, as well as a dose ratemeter, a radon daughter monitor and for navigation a GPS (Global Positioning System). The collection of gaseous iodine is optional. The meteorological parameters temperature, relative humidity, wind speed and wind direction are determined as well. Resulting data are transmitted by global VHF datalink (Very High Frequency) from the plane to the DWD headquarter and used for verifying the prognosis. In case of emergency the plane has to be airborne not later than 10 hours after alert. Homebase of the Learjet is a German military airbase, 100 km northwest of Hamburg. Six backup Learjets are available. The Learjet's service ceiling is 41,000 feet (12,330 m), cruising speed 800 km/hr, max. flying time 5 hrs. Originally developed to be operated in Germany, the Learjet can reach every destination in Europe within 3 hours. (author)

356

Absolute determination of the deuterium content of a heavy water sample D2O, measurement of its absolute density. Calculation of the absolute density of isotopically pure D216O  

International Nuclear Information System (INIS)

The absolute density of two heavy water samples rich in deuterium (with a grade higher than 99.9%) was determined with the hydrostatic method. The exact isotopic composition of this water (hydrogen and oxygen isotopes) was very carefully studied. A theoretical estimate allowed to get the absolute density value of isotopically pure D216O. This value was found to be 1104.750 kg.m-3 at t=22.3 deg C and under the pressure of one atmosphere

357

Measurement of absolute gamma ray emission probability of 1001 keV from the decay of 234mPa  

International Nuclear Information System (INIS)

In the direct ?-ray spectrometric measurements of 238U content, 1001 keV ?-ray of 234mPa is commonly used in recent years. 234mPa is the second daughter of 238U and rapidly reaches secular equilibrium with the parent nucleus. This clean peak is well resolved by high purity Ge detectors and gives more accurate indication of uranium content without requiring any self attenuation correction. Several measurements of the absolute emission probability of the 1001 keV ?-ray of 234mPa have resulted in doubts concerning the old recommended value 0.59±0.01 % obtained by a radiochemical method. Therefore, this old value is now absolute and a newly value of 0.835±0.004 % is recommended. In this study the ?-ray spectrometric measurements were carried out using the powdered U3O8 and the certified uranium samples. A new experimental value o 0.861±0.015 % for the absolute ?-ray emission probability for the 1001 keV gamma-ray of the 234mPa has been obtained. The present measured values agrees good with the most experimental results appeared in the literature and is close to the newly recommended values of 0.835±0.004 % and 0.837±0.012 % for the 1001 keV ?-ray of 234mPa

358

Extrapolation chamber for absolute energy dose rate measurement of beta and soft x radiation  

International Nuclear Information System (INIS)

A new extrapolation chamber is described, which is used as absolute standard for the determination of the absorbed beta radiation dose. The construction simulates a semi-infinite phantom and the absorbed dose to tissue was determined in tissue equivalent material. With a new system of concentric collecting electrodes it is possible to obtain the absorbed dose at the centre of the electrodes, which is extrapolated from five values of the surface of the collecting electrodes. (Author)

359

The research of a method of absolute measurement for laser-driven high pressure equation of state  

CERN Document Server

Numerical simulations of the whole physical process of aluminum flyer-vacuum-target directly driven by high power laser were presented. Simulation results showed that a symmetric impact will be realized between the flyer and the target and there is a wide stable area of shock wave propagation in the target if the parameters of flyer-vacuum-target and the conditions of laser match. And the absolute measurement of equation of state (EOS) may be approached if the structure parameters of flyer both-side-step-target are chosen reasonably. At the same time, the experimental researches of absolute measurement for EOS were conducted, and the experimental results are in accord with the simulation results on the whole

Huang Xiu Guang; Gu Yuan; Wu Jian; He Ju Hua; Luo Ping Qing; Ma Min Xun

2002-01-01

360

A radioactivity measuring device with a movable detector head  

International Nuclear Information System (INIS)

Specifications are given for a radiation measuring device for measuring radioactivity of a multiplicity of discrete samples comprising: (a) a mounting frame, (b) sample bearing means supported by the mounting frame for positioning a multiplicity of discrete samples at predetermined intervals from each other in a lateral array with samples depending from the sample bearing means, (c) a detector head containing at least one photodetector that generates electrical pulses of energy proportional to the energy in scintillations received, protected by a shielding means that defines an aperture extending proximate to each photodetector, (d) translation inducing means coupled to the detector head for moving the detector head laterally beneath the aforesaid samples to traverse the aforesaid array of samples and for moving the detector head vertically alternately between a lowered position located beneath the aforesaid samples and a raised position with a substantial portion of at least one depending sample extending into one of the aforesaid apertures in the shielding means proximate to a photodetector, (e) a scintillator sensitive to radioactive events located proximate to the photodetector and to samples extending into the apertures when the detector head is in the aforesaid raised position, and (f) pulse counting means connected to the photodetectors for receiving and tabulating pulses generated as a result of radioactive events occurring in the samples extending into the aprring in the samples extending into the apertures in the shielding of the detector head. (author)

 
 
 
 
361

Environmental radioactivity measurements in the autonomous community of Aragon  

International Nuclear Information System (INIS)

To know the level of environmental radioactivity in the Autonomous Community of Aragon thermoluminescent dosimeters used to measure the cumulative dose over a period of time in each of its 33 counties. The project, funded by the Government of Aragon and La Caixa to carry a map of environmental radioactivity with the collaboration of Secondary Schools and public schools for the renovation and shipment of dosimeters. The selection of the different locations was carried out taking into account the points of interest in the project reflected Marna, by ENUSA and the CSN, on natural gamma radiation. The work program began in 2009 and to date working with 43 centers distributed throughout the community tried to cover a wide surface area of Aragon. (Author)

362

GEMS: Underwater spectrometer for long-term radioactivity measurements  

Energy Technology Data Exchange (ETDEWEB)

GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by {sup 40}K decays but it can detect other natural (e.g., {sup 238}U,{sup 232}Th) and anthropogenic radio-nuclides (e.g., {sup 137}Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.

Sartini, Ludovica, E-mail: ludovica.sartini@ingv.i [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sect.Roma 2, Roma (Italy); Genoa University, Genoa (Italy); Simeone, Francesco; Pani, Priscilla [' Sapienza' University and Istituto Nazionale di Fisica Nucleare (INFN), Sect.Roma, Roma (Italy); Lo Bue, Nadia; Marinaro, Giuditta [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sect.Roma 2, Roma (Italy); Grubich, Andry; Lobko, Alexander [Institute for Nuclear Problems (INP), Belarus State University, Minsk (Belarus); Etiope, Giuseppe [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sect.Roma 2, Roma (Italy); Capone, Antonio [' Sapienza' University and Istituto Nazionale di Fisica Nucleare (INFN), Sect.Roma, Roma (Italy); Favali, Paolo [Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sect.Roma 2, Roma (Italy); Gasparoni, Francesco; Bruni, Federico [Tecnomare S.p.A., Venice (Italy)

2011-01-21

363

Environmental radioactivity measurements at BNL following the Chernobyl accident  

International Nuclear Information System (INIS)

Measurements are reported of the concentrations at Berkeley in Gloucestershire of radioactivity in the air, rainwater, tap water, soil, herbage and fresh vegetables for the period 29 April 1986 to 15 May 1986, following the Chernobyl Power Station accident. Data for up to 18 gamma emitting isotopes are reported, together with some limited actinide-in-air measurements. Deposition velocities are calculated and an assessment is presented of the sensitivity of the techniques employed. Some data are also included on the gaseous composition of the cloud and the isotope dependent dose rate from deposition. (author)

364

Radioactivity measurement of ?-nuclides by small solid angle method  

International Nuclear Information System (INIS)

Counting under a precise small solid angle is one of the oldest methods developed for the radioactivities measurement of ?-nuclides. The principle of solid angle counting is very simple and the accuracy is much better. The advantages of an equipment developed by the authors, in which a large area Au-Si surface barrier detector (450 mm2) is used, are introduced. Some comparisons on measurement results have been obtained with the gridded ionization chamber, and a national comparison result of 241Am which deviated from the average result is less than 0.2% are presented in detail

365

Uncertainties of DS86 and prospects for residual radioactivity measurement  

International Nuclear Information System (INIS)

Residual radioactivity data of 152Eu, 60Co and 36Cl have been accumulated and it has been revealed in the thermal neutron region that a systematic discrepancy exists between the measured data and activation calculation based on the DS86 neutrons in Hiroshima. Recently 63Ni produced in copper samples by the fast neutron reaction 63Cu(n,p)63Ni has been of interest for evaluation of fast neutrons. Reevaluation of atomic-bomb neutrons and prospects based on residual activity measurements have been discussed. (author)

366

Resolution limit of the white-light interferometric sensor for absolute position measurement based on central fringe maximum identification  

Science.gov (United States)

In this paper a simple theoretical analysis together with an experimental verification of the analysis that provides an estimation of the resolution limit of the white-light interferometric sensor for absolute position measurement based on central fringe maximum identification is presented. The resolution better than 10 pm is obtained in the white-light interferometric sensing system where the signal-to-noise ratio was greater than 80 dB.

Manojlovi?, L. M.; Živanov, M. B.; Slankamenac, M. P.; Stupar, D. Z.; Baji?, J. S.

2014-09-01

367

Application of a time-correlated associated particle method for absolute cross-section measurements of heavy nuclides  

International Nuclear Information System (INIS)

The joint fission cross-section measurements program of the V. G. Khlopin Radium Institute and the Technical University of Dresden is described. The errors and uncertainties of the time correlated associated particle method of fission cross-section measurements for 2.6, 8.5, and 14.7-MeV neutrons are discussed. Experimental results of absolute fission cross-section measurements of 235U, 238U, 237Np, and 239Pu for 14.7 MeV-neutrons and of 235U for 2.6 and 8.2-MeV neutrons are given

368

New measurements of absolute total cross sections for electron impact on caesium using a magneto-optical trap  

International Nuclear Information System (INIS)

A new magneto-optical trap designed specifically for the measurement of absolute electron impact cross sections is described. Experimental results for electron impact total cross sections involving 62S ground state Cs are presented over the energy range 5-200 eV. Significant disagreement is obtained between our experimental data and convergent close coupling (CCC) or Breit-Pauli R-matrix calculations at the lower energies. Above 100 eV our data overlap earlier measurements from this laboratory made with a completely different apparatus and agree well with the CCC results. A comparison is made with other measurements using more conventional techniques

369

Particle sizing of airborne radioactivity field measurements at Olympic Dam  

International Nuclear Information System (INIS)

On July 1, 1991 the Australian Radiation Laboratory (ARL) commenced a two year project entitled - Particle sizing of airborne radioactivity, funded by a Mining and Quarrying Occupational Health and Safety Committee - grant (submission No. 9138). This study was set out to measure airborne radioactivity size distributions in an underground uranium mine, in order to provide better estimates of the health risks associated with inhalation of airborne radiation in the work place. These measurements included both active and passive measurement of radon gas, continuous and spot sample of radon daughter levels, as well as wire screen diffusion battery measurements of the radon daughter size distributions. The results of measurements at over 50 sites within the mine are reported, together with the calculated dose conversion factors derived from the older dosimetric models and from the new ICRP lung model using the computer code RADEP. The results showed that the ventilation is relatively uniform within the mine and the radon daughter concentrations are kept to less than 20% of the equilibrium concentration. The radon and radon daughter concentrations showed marked variability with both time and position within the mine. It is concluded that the present radiation protection methods and dose conversion factors used in Australia provide a good estimate of the radiation risk for the inhalation of radon progeny. 29 refs., 8 tabs., 9 figs

370

Particle sizing of airborne radioactivity field measurements at Olympic Dam  

Energy Technology Data Exchange (ETDEWEB)

On July 1, 1991 the Australian Radiation Laboratory (ARL) commenced a two year project entitled - Particle sizing of airborne radioactivity, funded by a Mining and Quarrying Occupational Health and Safety Committee - grant (submission No. 9138). This study was set out to measure airborne radioactivity size distributions in an underground uranium mine, in order to provide better estimates of the health risks associated with inhalation of airborne radiation in the work place. These measurements included both active and passive measurement of radon gas, continuous and spot sample of radon daughter levels, as well as wire screen diffusion battery measurements of the radon daughter size distributions. The results of measurements at over 50 sites within the mine are reported, together with the calculated dose conversion factors derived from the older dosimetric models and from the new ICRP lung model using the computer code RADEP. The results showed that the ventilation is relatively uniform within the mine and the radon daughter concentrations are kept to less than 20% of the equilibrium concentration. The radon and radon daughter concentrations showed marked variability with both time and position within the mine. It is concluded that the present radiation protection methods and dose conversion factors used in Australia provide a good estimate of the radiation risk for the inhalation of radon progeny. 29 refs., 8 tabs., 9 figs.

Solomon, S.B.; Wilkis, M.; O`Brein, R.; Ganakas, G.

1993-12-01

371

Establishing radioactivity measurement capabilities for nuclear medicine in Member States  

International Nuclear Information System (INIS)

Full text: The International Atomic Energy Agency (IAEA), in response to a growing need for measurement quality assurance for radionuclides used in nuclear medicine, particularly in developing countries, is establishing a new radioactivity standardization programme in the Dosimetry and Medical Radiation Physics Section. The short-term (3-5 years) goals of this project are to: 1) Develop capabilities within the IAEA to prepare and distribute calibrated solution sources of medically relevant radionuclides, traceable to international standards, to Member States for use in calibrating instrumentation. Traceability will be established through comparisons with primary National Measurement Laboratories, as well as with the International Reference System for activity measurements of the BIPM. Ultimately, the goal will be for the Agency to be able to distribute standard sources of the most relevant radionuclides to Member States that require them as part of a secondary standards radioactivity laboratory network. The laboratories in the network will then provide calibration and auditing services to nuclear medicine clinics on a national or regional basis. Formation of the laboratory network is ongoing. 2) Assist Member States in the development of quality assurance networks for nuclear medicine clinics in their countries. This could be accomplished through Technical Cooperation projects at the national and regional levels and will take the form of personnel training and consultations to develop appropriate quality assurance and audit systems, and in some cases, donation of appropriate instrumentation. Further, a Coordinated Research Project has recently been approved to develop a uniform code of practice for clinical radioactivity measurements. Formation of the research group will begin in early 2004. (author)

372

Absolute measurements of the alpha-gamma emitters activities by a sum-coincidence method  

International Nuclear Information System (INIS)

The absolute activity of U-235 contained in a UO2 sample, using a sum-coincidence circuit which selected only the alpha particles which were simultaneous with the well known 184 Kev gamma radiation from Th-231. The alpha particles were detected by ZnS(Ag) scintillator specially designed to show its maximun efficiency for U-235 alpha particles, whereas the gamma radiation was detected by NaI(Tl) scintillation detector. The values obtained for the half-life of U-235 was compared with data from various observers using different experimental techniques. (Author)

373

In situ TDLAS measurement of absolute acetylene concentration profiles in a non-premixed laminar counter-flow flame  

Science.gov (United States)

Acetylene (C2H2), as an important precursor for chemiluminescence species, is a key to understand, simulate and model the chemiluminescence and the related reaction paths. Hence we developed a high resolution spectrometer based on direct Tunable Diode Laser Absorption Spectroscopy (TDLAS) allowing the first quantitative, calibration-free and spatially resolved in situ C2H2 measurement in an atmospheric non-premixed counter-flow flame supported on a Tsuji burner. A fiber-coupled distributed feedback diode laser near 1535 nm was used to measure several absolute C2H2 concentration profiles (peak concentrations up to 9700 ppm) in a laminar non-premixed CH4/air flame ( T up to 1950 K) supported on a modified Tsuji counter-flow burner with N2 purge slots to minimize end flames. We achieve a fractional optical resolution of up to 5×10-5 OD (1 ?) in the flame, resulting in temperature-dependent acetylene detection limits for the P17e line at 6513 cm-1 of up to 2.1 ppm?m. Absolute C2H2 concentration profiles were obtained by translating the burner through the laser beam using a DC motor with 100 ?m step widths. Intercomparisons of the experimental C2H2 profiles with simulations using our new hydrocarbon oxidation mechanisms show excellent agreement in position, shape and in the absolute C2H2 values.

Wagner, S.; Klein, M.; Kathrotia, T.; Riedel, U.; Kissel, T.; Dreizler, A.; Ebert, V.

2012-06-01

374

The radioactivity measurements in soil, coal and water in south Marmara region of Turkey  

International Nuclear Information System (INIS)

Radioactivity levels were determined in soil, coal and water samples collected from various locations in the south Marmara region of Turkey. The activities in samples were determined using TENNELEC LB 1000-PW detector. The absolute beta activities were observed to vary in the range 0.83+/-0.06-0.50+/-0.05 for soil in units of Bqg-1, and 1.284+/-0.02-0.079+/-0.002 for coal samples in units of Bqg-1 and 0.74+/-0.05-0.06+/-0.02 for water in units of Bql-1. In addition, gamma spectra of soil and coal samples which have highest level of beta activities were measured by using HpGe detector. 235U, 214Pb, 134Cs, 137Cs, 214Bi and 40K were detected in soil samples. 235U, 214Pb, 134Cs and 214Bi were detected in coal samples. The radioactivity levels in water samples were compared with WHO and ITS recommended levels and the literature values

375

Absolute optical frequency measurements of Cs two-photon transitions with a femtosecond frequency comb  

Science.gov (United States)

We study by direct excitation with a mode-locked femtosecond optical frequency comb, multiple transitions in Cs atoms in a vapor cell at room temperature. We improve by up to two orders of magnitude the uncertainties in the absolute optical frequency and hyperfine structure of the 6s ^2 S1/2->8s ^2 S1/2,9s ^2 S1/2, and 7d ^2 D3/2,5/2 transitions in ^133Cs. Cesium is one of the well studied heavy atoms, with atomic structure calculations on the order of 1%, and has provided a fertile testbed for fundamental tests of atomic theory and QED. This work reports on a simple and novel experimental approach that allows simultaneous recording of multiple transition frequencies. Atoms in a vapor cell at room temperature have a broad Doppler velocity distribution which allow selective excitation by discrete modes of a mode-locked femtosecond comb. This, in turn, results in stepwise multiphoton resonant transitions in the atoms. We model the collected spectra using a standard 2? formula and use least square fitting routines to extract improved values of absolute optical frequencies and coupling constants.

Mbele, Vela L.; Stalnaker, Jason E.; Gerginov, Vladislav; Fortier, Tara; Tanner, Carol E.; Diddams, Scott A.; Hollberg, Leo

2007-03-01

376

A fast signal subspace approach for the determination of absolute levels from phased microphone array measurements  

Science.gov (United States)

Phased microphone arrays are used in a variety of applications for the estimation of acoustic source location and spectra. The popular conventional delay-and-sum beamforming methods used with such arrays suffer from inaccurate estimations of absolute source levels and in some cases also from low resolution. Deconvolution approaches such as DAMAS have better performance, but require high computational effort. A fast beamforming method is proposed that can be used in conjunction with a phased microphone array in applications with focus on the correct quantitative estimation of acoustic source spectra. This method bases on an eigenvalue decomposition of the cross spectral matrix of microphone signals and uses the eigenvalues from the signal subspace to estimate absolute source levels. The theoretical basis of the method is discussed together with an assessment of the quality of the estimation. Experimental tests using a loudspeaker setup and an airfoil trailing edge noise setup in an aeroacoustic wind tunnel show that the proposed method is robust and leads to reliable quantitative results.

Sarradj, Ennes

2010-04-01

377

? radioactive aerosol's measurement and analysis in an area  

International Nuclear Information System (INIS)

In order to know long-life radioactive aerosol's concentration in the atmosphere in three places of the area, evaluate radioactive environment's quality and the radioactive aerosol's infection to the teachers and students, we investigate radioactive aerosol's concentration in the working place, living place and teaching place of the area. The result shows that the radioactive aerosol's concentration of the area is under the country's control criterion. (authors)

378

Direct measurements of neutron capture on radioactive isotopes  

CERN Document Server

We simulated the response of a 4p calorimetric g-detector array to decays of radioactive isotopes on the s-process path. The GEANT 3.21 simulation package was used. The main table contains estimates on the maximum sample size and required neutron flux based on the latest available neutron capture cross section at 30 keV. The results are intended to be used to estimate the feasibility of neutron capture measurements with 4p arrays using the time of flight technique.

Couture, A

2009-01-01

379

Standard cartridges used in gamma spectrometry measurements of radioactive halogens  

International Nuclear Information System (INIS)

Activated charcoal cartridges are used to trap radioactive halogens contained in gaseous effluents of nuclear facilities. Two types of standard cartridges, with barium 133 or europium 152 are available. One of the models simulates a volumic distribution, and the other a surface distribution of the radionuclides inside the cartridge. They are characterized in terms of activity with an uncertainty lower than 5 %. The standard cartridges utilization conditions are specified and the main measurement error causes are analyzed. The proper routine use of these standards should allow us to get results with an accuracy better than 10 %

380

Environmental radioactivity measurements Using a compton suppression spectrometer  

International Nuclear Information System (INIS)

The natural and artificial radioactivities of some environmental samples such as soil and vegetables have been studied through gamma-ray spectroscopy with a new constructed compton suppression spectrometer (CSS). The spectrometer consists of a 10% p-type HPGe detector as a main detector, an annular NE-102 A plastic scintillator as a guard detector, and a fast-slow coincidence system employing standard electronic modules for anti-compton operation. This study shows that CSS is a powerful tool for measuring the low level activities of environmental samples

 
 
 
 
381

Radioecological observations in the trace-measurement and dosimetric evaluation of radioactive traces in the air  

International Nuclear Information System (INIS)

The following topics are dealt with: Weekly measurement of 137Cs and 40K, long-time measurement series, natural radioactive nuclides, artificial radioactive nuclides, 85Kr, 133Xe, 90Sr, 137Cs, and 238-240Pu, the radioecology of 129I, dosimetric evaluation of radioactive traces in air. (HSI)

382

Measurement of OEF and absolute CMRO2: MRI-based methods using interleaved and combined hypercapnia and hyperoxia.  

Science.gov (United States)

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is most commonly used in a semi-quantitative manner to infer changes in brain activity. Despite the basis of the image contrast lying in the cerebral venous blood oxygenation level, quantification of absolute cerebral metabolic rate of oxygen consumption (CMRO2) has only recently been demonstrated. Here we examine two approaches to the calibration of fMRI signal to measure absolute CMRO2 using hypercapnic and hyperoxic respiratory challenges. The first approach is to apply hypercapnia and hyperoxia separately but interleaved in time and the second is a combined approach in which we apply hyperoxic challenges simultaneously with different levels of hypercapnia. Eleven healthy volunteers were studied at 3T using a dual gradient-echo spiral readout pulsed arterial spin labelling (ASL) imaging sequence. Respiratory challenges were conducted using an automated system of dynamic end-tidal forcing. A generalised BOLD signal model was applied, within a Bayesian estimation framework, that aims to explain the effects of modulation of CBF and arterial oxygen content to estimate venous deoxyhaemoglobin concentration ([dHb]0). Using CBF measurements combined with the estimated oxygen extraction fraction (OEF), absolute CMRO2 was calculated. The interleaved approach to hypercapnia and hyperoxia, as well as yielding estimates of CMRO2 and OEF demonstrated a significant increase in regional CBF, venous oxygen saturation (SvO2) (a decrease in OEF) and absolute CMRO2 in visual cortex in response to a continuous (20 min) visual task, demonstrating the potential for the method in measuring long term changes in CMRO2. The combined approach to oxygen and carbon dioxide modulation, as well as taking less time to acquire data, yielded whole brain grey matter estimates of CMRO2 and OEF of 184±45 ?mol/100 g/min and 0.42±0.12 respectively, along with additional estimates of the vascular parameters ?=0.33±0.06, the exponent relating relative increases in CBF to CBV, and ?=1.35±0.13, the exponent relating deoxyhaemoglobin concentration to the relaxation rate R2*. Maps of cerebrovascular and cerebral metabolic parameters were also calculated. We show that combined modulation of oxygen and carbon dioxide can offer an experimentally more efficient approach to estimating OEF and absolute CMRO2 along with the additional vascular parameters that form an important part of the commonly used calibrated fMRI signal model. PMID:23769703

Wise, Richard G; Harris, Ashley D; Stone, Alan J; Murphy, Kevin

2013-12-01

383

Radioactivity measurements in the vicinity of Swiss nuclear power plants  

International Nuclear Information System (INIS)

To determine the radionuclide concentration in soil and on soil surface, respectively, caused by radionuclide releases from nuclear power plants, field gamma spectrometry is used to obtain, in a short period of time, quantitative data about the environmental radiation field, natural or man-made. This is obviously difficult to achieve by conventional sampling methods and laboratory analysis. This word describes the instruments used and the calibration methods, and gives the results of in situ measurements made around the Swiss nuclear power plants. The measurements and computations are compared with a laboratory analysis of collected soil samples and with total exposure rate measurements in air. In addition to natural radioactivity this method allows especially the detection of radionuclides released from nuclear power stations to the environment with a good sensitivity. (orig.)

384

Trace radioactive measurement in foodstuffs using high purity germanium detector  

International Nuclear Information System (INIS)

Trace radioactivity in food has been seriously considered sources of potential harm after the accidental radioactive releases in the last decades which led to contamination of the food chain. Countermeasures are being used to reduce the radiological health risk to the population and to ensure that public safety and international commitments are met. Investigation of radioactive traces in foods was carried out by gamma-ray spectrometry. The radionuclides being measured were fission products 137Cs and 134Cs and naturally occurring 40?. Gamma-ray measurements were performed using a hybrid gamma-ray counting system with coaxial p-type Tennelec High Purity Germanium (HPGe) detector with relative efficiency of 18.4%. Channels were calibrated to energies using a standard check source with 137Cs and 60Co present. Self-shielding within samples was taken into account by comparing directly with reference standards of similar matrix and geometry. Efficiencies of radionuclides of interests were accounted in calculating the activity concentrations in the samples. Efficiency calibration curve was generated using an in-house validated program called FINDPEAK, a least-square method that fits a polynomial up to sixth-order of equation. Lower Limits of Detection (LLD) obtained for both 137Cs and 134Cs ranges from 1-6 Bq/Kg depending on the sample matrix. In the last five years, there have been no foodstuffs ane years, there have been no foodstuffs analyzed exceeded the local and international regulatory limit of 1000Bq/Kg for the summed activities of 137Cs and 134Cs. (author)

385

Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy  

Science.gov (United States)

The first absolute wind velocities above the Venusian cloud-tops were obtained using NASA/Goddard infrared heterodyne spectrometers at the NASA Infrared Telescope Facility (IRTF) and the McMath Solar Telescope. Beam-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 micron R(8) sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than + or - 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam (1.7 arc-second HPBW at McMath, 0.9 arc-second HPBW at IRTF), and 1 to 2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds provided definitive evidence of a dominant subsolar-antisolar circulation in the lower thermosphere. Beam-integrated winds were modelled with a 100x100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s equatorial velocity. A review of all dynamical indicators above the cloud-tops allowed development of an integrated and self-consistent picture of circulation in the 70 to 200 km range.

Goldstein, Jeffrey J.

1990-01-01

386

Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy  

International Nuclear Information System (INIS)

The first absolute wind velocities above the Venusian cloud-tops were obtained using NASA/Goddard infrared heterodyne spectrometers at the NASA Infrared Telescope Facility (IRTF) and the McMath Solar Telescope. Beam-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 micron R(8) sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than + or - 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam (1.7 arc-second HPBW at McMath, 0.9 arc-second HPBW at IRTF), and 1 to 2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds provided definitive evidence of a dominant subsolar-antisolar circulation in the lower thermosphere. Beam-integrated winds were modelled with a 100x100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s eqetrograde zonal component with a 25 m/s equatorial velocity. A review of all dynamical indicators above the cloud-tops allowed development of an integrated and self-consistent picture of circulation in the 70 to 200 km range

387

Measurement of radioactive soil contamination from the air  

International Nuclear Information System (INIS)

In-situ gamma spectrometry can be used to determine the qualitative and quantitative deposition of radioactive materials on the ground surface. By applying the in-situ spectrometry method using either a helicopter or an airplane, large areas can be scanned in a short period of time. In this report the results of in-situ gamma spectroscopic measurements taken from a helicopter are described. Measurements were carried out using a single point source, a field of 36 point sources, and using the present ground contamination due to fall-out from the Chernobyl accident and atom bombs. The results of these measurements were used to determine calibration factors, which were in agreement with a calibration obtained using more simple (and less expensive) laboratory measurements in combination with flux calculations. Detection limits for the measurement of surface contamination were determined. At a height of 50 meters above the surface and using a measurement time of 2 minutes, the minimally detectable surface contamination was 1.1 kBqm-2 for a Cs-137 contamination and 2.1 kBqm-2 for I-131 contamination. Fall-out determinations based on measurements taken at a height of 50 meters were in agreement with determinations taken at a height of 1 meter, and with the results obtained measuring soil samples. The in-situ gamma spectroscopy, using helicopter or airplane, is a fast and powerful method for mapping surface contamination. (author). 13 refs.; 18 figs.; 13 ination. (author). 13 refs.; 18 figs.; 13 tabs

388

SAXS/WAXS Capability and Absolute Intensity Measurement Study at the SAXS Beamline of the Siam Photon Laboratory  

International Nuclear Information System (INIS)

A Small Angle X-ray Scattering (SAXS) beamline has been constructed at the Siam Photon Laboratory of the Synchrotron Light Research Institute (SLRI), Thailand. The beamline was commissioned and opened for users in March 2011. In order to maximize the photon flux, a Double Multilayer Monochromator was adopted to monochromatize synchrotron x-rays within the energy range of 6-9 keV. The experimental station is equipped with a CCD detector for SAXS measurements and an Image Plate for wide angle x-ray scattering (WAXS) measurements. Apparatus for in-situ measurements have been developed to enable studies of nano structural changes during temperature and tensile variation. Capability for scattering measurements in absolute unit has been investigated. This work reports the current status of the beamline and results from dispersed Au nanoparticles measurements.

389

High-accuracy absolute distance measurement by two-wavelength double heterodyne interferometry with variable synthetic wavelengths  

CERN Document Server

We present an absolute distance measurement interferometer based on a two wavelength interferometer and a variable synthetic wavelength technique. The wavelength scanning range was 12 GHz, realized with a phase accuracy of 1.0 m{\\lambda} by heterodyne detection at each measurement wavelength. This small wavelength scanning range enabled the use of distributed feedback laser diodes as an interferometer light source and a fast 20 ms wavelength scanning time by injection current control. We demonstrated a measurement range of up to 1.5 m and an accuracy better than 1.2 nm in comparison with a displacement measurement interferometer, corresponding to a relative accuracy of 10-9. In addition, we also proposed expanding the range of maximum measurement and compensation of refractive index of air for linear colliders.

Kuramoto, Yoshiyuki

2014-01-01

390

Measuring of the radioactivity of liquid wastes and sewage sludge  

International Nuclear Information System (INIS)

A mobile control station (MCS) and a central laboratory-based measuring system (CL) were developed for monitoring the level of the radioactivity of sewage and sludge in the public sewage system of Budapest (capital of Hungary). The gamma and beta activity of the samples can be measured in situ by MCS, as for alpha and soft beta rays the CL (with liquid-scintillation technique) is used. Gamma and beta isotopes with very low specific activity can be detected by thermoluminescent dosimeters located at in special sites in the sewage system. The quantity of the isotopes applied, especially sup(99m)Tc, has been increasing therefore an increasing local activity level must be taken into consideration for the sewage system of the capital. (Sz.J.)

391

Diagnostic measures and therapeutic possibilities in incorporations of radioactive substances  

International Nuclear Information System (INIS)

In the interest of better understanding the diagnostic measures to be taken in cases of incorporation, the exposure pathways of an incorporation are outlined and their physical and chemical mechanisms described. Attention is drawn to the need for interdisciplinary cooperation with health physics. Therapeutic possibilities are indicated for both first aid measures and further treatment by the authorized physician. These efforts are intended to reduce the absorption of the radionuclide from the gastro-intestinal tract, prevent the ascension of activity from a wound deposit to the transfer compartiment, and impede depostions of the radioactive substance in some organs. In-house experience accumulated in the treatment of incorporation accidents associated with transuranium isotopes is described on the basis of some case reports. (orig.)

392

Standardisation of 125I using seven techniques for radioactivity measurement  

International Nuclear Information System (INIS)

Seven methods of radioactivity measurement were used to standardise an 125I solution within the frame of an international key comparison organised by BIPM: photon-photon coincidence counting with two NaI detectors, photon sum-peak counting in a NaI well detector and in a 4? CsI(Tl) sandwich spectrometer, total emission counting in a windowless 4? CsI(Tl) sandwich spectrometer, electron-X,? coincidence counting and electron-X,? sum counting in a pressurised proportional counter inside a NaI well detector and liquid scintillation counting with the CIEMAT/NIST method. The solid sources were prepared by quantitative drop deposition with addition of AgNO3. The measurement methods, the results and the applied corrections are described and discussed

393

Quality assurance for radioactive measurement in nuclear medicine  

International Nuclear Information System (INIS)

ging aspects had each become so specialized as to be better treated in separate publications. The present report focuses on the factors affecting radioactivity measurement and the implementation of QA and QC programmes to ensure accurate and consistent results. The IAEA has developed a safety standard on The Management System for Facilities and Activities (IAEA Safety Standards Series No. GS-R-3), which replaces the IAEA publications on QA issued as Safety Series No. 50-C/SG-Q (1996). In GS-R-3, the management system is described as a set of interrelated or interacting elements for establishing policies and objectives and enabling the objectives to be achieved in a safe and efficient way. The management system is designed to fulfil requirements that integrate elements related to safety, health, the environment, security, quality and economics. Safety is the fundamental principle upon which the management system is based. It is also recognized in GS-R-3 that QC and QA are important components of the management system. While QC is a means of applying controls to ensure that the product or service consistently meets specifications, QA is an interdisciplinary management tool that provides a means for ensuring that all work is adequately planned, correctly performed and assessed. A QA programme is designed primarily to ensure the quality of a product for a customer and may be appropriate to control the activities in radioactivity measurement in nuclear medicine. However, it would be more effective if these QA controls were integrated into a single management system. There are numerous processes that review and assess financial and technical performance, the achievement of goals and the effectiveness of an organization's processes. It is necessary to integrate the results of all assessment activities to focus decision making on the needs of the business strategy. It is important to understand how assessments enable managers to achieve higher standards of performance. The principles in this publication are based on those described in IAEA Safety Standards Series No. GS-R-3 and in the General Requirements for the Competence of Testing and Calibration Laboratories (ISO/IEC 17025:1999), which set requirements that testing and calibration laboratories must meet to demonstrate that they have a management system in place and are technically competent. The present report provides information specific to implementing these standards at both the end user (clinic) and the secondary standards radioactivity laboratory levels. If adopted to their greatest extent, the principles herein will provide the user with al l the information (including measurement procedures) necessary to carry out most tasks associated with routine radioactivity measurement, including maintaining the necessary documentation. The primary audience for this report includes radiopharmacists, nuclear medicine technologists, medical physicists, technicians in secondary standards radioactivity laboratories and managers responsible for the operation of such facilities

394

Improvement of a new portable monitor for measuring radioactivity levels  

International Nuclear Information System (INIS)

ion of radiopharmaceutical agent. The newly developed portable monitor was adaptable to determine the radioactivity of inner organs directly from the outside of the body surface, and is effective in clinical management for excretion of clinical radioactive agents. (author)

395

Absolute total cross section measurements of ion pair production in H(1s)-H(2s) collisions  

International Nuclear Information System (INIS)

This paper reports absolute cross section measurements of the ion pair production Hsub(A)(2s)+Hsub(B)(1s)?H+sub(A)+H-sub(B) using a merged beams experiment. Four centre-of-mass energies have been investigated between 85 and 325 eV. The results are found to be in good agreement with recent theoretical predictions. The distinction made between 'direct' (like the reaction studied) and 'indirect' (i.e. Hsub(A)(2s)+Hsub(B)(1s)?H-sub(A)+H+sub(B)) charge exchange is confirmed. (author)

396

Measurements of the Absolute Branching Fractions of B^\\pm --> K^\\pm X_{c\\bar c}  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study the two-body decays of B^\\pm mesons to K^\\pm and a charmonium state, X_{c\\bar c}, in a sample of 210.5 fb^{-1} of data from the BaBar experiment. We perform measurements of absolute branching fractions BR(B^\\pm --> K^\\pm X_{c\\bar c}) using a missing mass technique, and report several new or improved results. In particular, the upper limit BR(B^\\pm --> K^\\pm X(3872)) J/\\psi\\pi^+\\pi^-)>4.2% will help in u...

Babar, The Collaboration; Aubert, B.

2005-01-01

397

Absolute Measurement of Baselines up to 403 m Using Heterodyne Temporal Coherence Interferometer with Optical Frequency Comb  

Science.gov (United States)

A heterodyne interference system is developed for baseline measurement by using an acoustic optical modulator and an optical frequency comb stabilized by a rubidium atomic clock. Temporal coherence interference occurs at discrete spatial positions, when two pulse trains overlap. An optical delay of the interferometer with a piezoelectric transducer is created to determine the peak positions of the interference fringe patterns, and the absolute distance is obtained at a high resolution of several tens of nanometers. The experimental results at baseline distances up to 403.2 m show a high reproducibility of about 6 µm.

Matsumoto, Hirokazu; Wang, Xiaonan; Takamasu, Kiyoshi; Aoto, Tomohiro

2012-04-01

398

Measurements of the Absolute Branching Fractions of B^\\pm --> K^\\pm X_{c\\bar c}  

CERN Document Server

We study the two-body decays of B^\\pm mesons to K^\\pm and a charmonium state, X_{c\\bar c}, in a sample of 210.5 fb^{-1} of data from the BaBar experiment. We perform measurements of absolute branching fractions BR(B^\\pm --> K^\\pm X_{c\\bar c}) using a missing mass technique, and report several new or improved results. In particular, the upper limit BR(B^\\pm --> K^\\pm X(3872)) J/\\psi\\pi^+\\pi^-)>4.2% will help in understanding the nature of the recently discovered X(3872).

Aubert, B; Abrams, G S; Adye, T; Ahmed, M; Ahmed, S; Alam, M S; Albert, J; Aleksan, Roy; Allen, M T; Allison, J; Allmendinger, T; Altenburg, D; Andreassen, R; Andreotti, M; Angelini, C; Anulli, F; Arnaud, N; Aston, D; Azzolini, V; Baak, M; Back, J J; Baldini-Ferroli, R; Band, H R; Banerjee, S; Barate, R; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Battaglia, M; Bauer, J M; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Benelli, G; Berger, N; Bernard, D; Berryhill, J W; Best, D; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bhuyan, B; Bianchi, F; Biasini, M; Biesiada, J; Blanc, F; Blaylock, G; Blinov, A E; Blinov, V E; Bloom, P; Bomben, M; Bondioli, M; Bonneaud, G R; Bosisio, L; Boutigny, D; Bowerman, D A; Boyarski, A M; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Breon, A B; Briand, H; Brose, J; Brown, C L; Brown, C M; Brown, D; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Buchmüller, O L; Bugg, W; Bukin, A D; Bula, R; Bulten, H; Burchat, P R; Burke, J P; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Capra, R; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Cenci, R; Chai, X; Chaisanguanthum, K S; Chao, M; Charles, E; Charles, M J; Chauveau, J; Chavez, C A; Chen, A; Chen, C; Chen, E; Chen, J C; Chen, S; Chen, X; Cheng, B; Cheng, C H; Chevalier, N; Cibinetto, G; Clark, P J; Claus, R; Cochran, J; Coleman, J P; Contri, R; Convery, M R; Cormack, C M; Cossutti, F; Cottingham, W N; Couderc, F; Covarelli, R; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L; Cristinziani, M; Cunha, A; Curry, S; Côte, D; D'Orazio, A; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; Day, C T; De Groot, N; De Nardo, Gallieno; De Sangro, R; Del Buono, L; Del Re, D; Della Ricca, G; Di Lodovico, F; Di Marco, E; Dickopp, M; Dingfelder, J C; Dittongo, S; Dong, D; Dorfan, J; Druzhinin, V P; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Eckhart, E A; Eckmann, R; Edgar, C L; Edwards, A J; Egede, U; Eichenbaum, A M; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Eyges, V; Fabozzi, F; Faccini, R; Fan, S; Feltresi, E; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Flacco, C J; Flack, R L; Flächer, H U; Flood, K T; Ford, K E; Ford, W T; Forster, I J; Forti, F; Fortin, D; Foulkes, S D; Franek, B; Frey, R; Fritsch, M; Fry, J R; Fulsom, B G; Gabathuler, E; Gaidot, A; Gaillard, J R; Galeazzi, F; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gary, J W; Gaspero, M; Gatto, C; George, K A; Gill, M S; Giorgi, M A; Giroux, X; Gladney, L; Glanzman, T; Godang, R; Goetzen, K; Golubev, V B; Gopal, G P; Gowdy, S J; Gradl, W; Graham, M; Grancagnolo, S; Graugès-Pous, E; Graziani, G; Green, M G; Grenier, P; Gritsan, A V; Grosdidier, G; Groysman, Y; Guo, Q H; Hadavand, H K; Hadig, T; Haire, M; Halyo, V; Hamano, K; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, A J; Hartfiel, B L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hill, E J; Hirschauer, J F; Hitlin, D G; Hodgkinson, M C; Hollar, J J; Hong, T M; Honscheid, K; Hopkins, D A; Hrynóva, T; Hufnagel, D; Hulsbergen, W D; Hutchcroft, D E; Höcker, A; Igonkina, O; Innes, W R; Izen, J M; Jackson, P D; Jackson, P S; Jacobsen, R G; Jawahery, A; Jessop, C P; John, M J J; Johnson, J R; Judd, D; Kadel, R W; Kadyk, J; Kagan, H; Karyotakis, Yu; Kass, R; Kelly, M P; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Kitayama, I; Klose, V; Knecht, N S; Koch, H; Kocian, M L; Koeneke, K; Kofler, R; Kolomensky, Yu G; Koptchev, V B; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kravchenko, E A; Kreisel, A; Krishnamurthy, M; Kroeger, R; Kroseberg, J; Kukartsev, G; Kutter, P E; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lanceri, L; Lange, D J; Langenegger, U; Lankford, A J; Latham, T E; Lau, Y P; Lazzaro, A; Le Diberder, F R; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Lewandowski, B; Li Gioi, L; Li, H; Li, X; Libby, J; Lista, L; Liu, R; Lo Vetere, M; LoSecco, J M; Lockman, W S; Lombardo, V; London, G W; Long, O; Lou, X C; Lu, M; Luitz, S; Lund, P; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lü, C; Lüth, V; MacFarlane, D B; Macri, M; Mader, W F; Majewski, S A; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Marchiori, G; Margoni, M; Marks, J; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mayer, B; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Meadows, B T; Mellado, B; Menges, W; Messner, R; Meyer, W T; Mihályi, A; Minamora, J S; Mir, L M; Mohanty, G B; Mohapatra, A K; Mommsen, R K; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morgan, S E; Morganti, M; Morganti, S; Morii, M

2006-01-01

399

System parameters and measurement instrument parameters are not separately observable: Relational mass is observable while absolute mass is not  

CERN Document Server

A brief summary of the objections to the relational nature of inertial mass, gravitational mass and electric charge is presented. The objections are refuted by showing that the measurement process of comparing an instrument reference clock and a reference rod both obeying the laws of physics to a system obeying the same laws of physics results in relational quantities: inertial mass, gravitational mass and electric charge appear only as ratios. This means that scaling of the absolute inertial mass of every object in the universe by the same factor is unobservable (likewise for gravitational mass and electric charge). It is shown that the measurement process does not separate the instrument parameters from the system parameters. Instead a measurement produces functions of fundamental, dimensionless parameters such as the fine structure constant, electron-proton mass ratio and the proton gyro-magnetic factor. It is shown that the measurement of Planck's constant also results in such a function of these dimensio...

Holt, Craig R

2014-01-01

400

3D absolute shape measurement of live rabbit hearts with a superfast two-frequency phase-shifting technique.  

Science.gov (United States)

This paper presents a two-frequency binary phase-shifting technique to measure three-dimensional (3D) absolute shape of beating rabbit hearts. Due to the low contrast of the cardiac surface, the projector and the camera must remain focused, which poses challenges for any existing binary method where the measurement accuracy is low. To conquer this challenge, this paper proposes to utilize the optimal pulse width modulation (OPWM) technique to generate high-frequency fringe patterns, and the error-diffusion dithering technique to produce low-frequency fringe patterns. Furthermore, this paper will show that fringe patterns produced with blue light provide the best quality measurements compared to fringe patterns generated with red or green light; and the minimum data acquisition speed for high quality measurements is around 800 Hz for a rabbit heart beating at 180 beats per minute. PMID:23482151

Wang, Yajun; Laughner, Jacob I; Efimov, Igor R; Zhang, Song

2013-03-11

 
 
 
 
401

Measurement of environmental radioactivity in Toki district, (2)  

International Nuclear Information System (INIS)

Three and a half years have elapsed since the start of this joint research. At first, cosmic ray was measured with a Geiger counter made by ourselves, then strong radioactivity was found in soils and stones. In order to observe the natural environment in which we live from the viewpoint of radiation, the measuring instrument having better sensitivity and on which the effect of background is small was sought for. The main subject of this report is the progress during this period, accordingly, the circuit composition of a NaI scintillation counter, thermo-luminescent dosimeter and ionization chamber measurement are described. When the Tokitsu Elementary School was reconstructed from wooden structure to concrete structure, the exposure dose in the teacher's room doubled. One summer day, mutual comparison was carried out among the measurement with a Geiger counter, a NaI scintillator and a TLD using an ionization chamber as the reference. The features of various measuring instruments were clarified, and utilizing these results, the effect of the combined measurement can be obtained. (Kako, I.)

402

Accurate radiocarbon age estimation using "early" measurements: a new approach to reconstructing the Paleolithic absolute chronology  

Science.gov (United States)

This paper presents new correction approaches for "early" radiocarbon ages to reconstruct the Paleolithic absolute chronology. In order to discuss time-space distribution about the replacement of archaic humans, including Neanderthals in Europe, by the modern humans, a massive data, which covers a wide-area, would be needed. Today, some radiocarbon databases focused on the Paleolithic have been published and used for chronological studies. From a viewpoint of current analytical technology, however, the any database have unreliable results that make interpretation of radiocarbon dates difficult. Most of these unreliable ages had been published in the early days of radiocarbon analysis. In recent years, new analytical methods to determine highly-accurate dates have been developed. Ultrafiltration and ABOx-SC methods, as new sample pretreatments for bone and charcoal respectively, have attracted attention because they could remove imperceptible contaminates and derive reliable accurately ages. In order to evaluate the reliability of "early" data, we investigated the differences and variabilities of radiocarbon ages on different pretreatments, and attempted to develop correction functions for the assessment of the reliability. It can be expected that reliability of the corrected age is increased and the age applied to chronological research together with recent ages. Here, we introduce the methodological frameworks and archaeological applications.

Omori, Takayuki; Sano, Katsuhiro; Yoneda, Minoru

2014-05-01

403

Absolute left ventricular volume from gated blood pool imaging with use of esophageal transmission measurement  

International Nuclear Information System (INIS)

A new method for determining absolute left ventricular (LV) volume from equilibrium gated blood pool images was validated in 36 patients by comparing gated blood pool (GBP) imaging with contrast ventriculography (CV) using both Simpson's rule (SR) and area-length (AL) calculations. The technique is geometry-independent and is the first to correct for tissue attenuation with use of an in vivo point source. An orally administered capsule containing 1 to 2 mCi of technetium-99m (Tc-99m) sulfur colloid is used for this purpose. Left ventricular volumes are determined by dividing attenuation and background-corrected count rates obtained from semiautomated LV regions of interest by the count rate per milliliter from a blood sample. The correlation between GBP and CV (SR) was 0.96 (CV [SR] . 0.99 GBP + 1.32 ml; standard error of the estimate [SEE] . 21.2 ml) for diastole and 0.97 (CV [SR] . 0.93 GBP - 0.03 ml; SEE . 11.9 ml) for systole. The correlation between GBP and CV (AL) was 0.92 (CV [AL] . 0.90 GBP + 16.72 ml; SEE . 27.8 ml) for diastole and 0.95 (CV [AL] . 0.87 GBP + 4.56 ml; SEE . 14.4 ml) for systole. The method is noninvasive and can be performed easily as part of routine gated blood pool imaging and analysis

404

Measurement of absolute gamma-ray emission probabilities from decay of 138Xe.  

Science.gov (United States)

The fission gaseous (138)Xe products play an important role in the research of nuclear-reaction products and radioisotope applications. Therefore, precise data for emission probabilities of gamma-ray from decay of (138)Xe are highly desired. However, a high precision is not achievable with a sufficient accuracy due to the limitations of the usual experimental techniques. In this paper, after the homogeneous sources of (138)Xe-(138)Cs were prepared, the activity of (138)Xe was obtained by the decay relationship between (138)Xe and (138)Cs using a HPGe detector. The full-energy peak efficiencies of gamma-ray for (138)Xe and (138)Cs were accurately calibrated using many activity standard sources and self-absorption was corrected. As a result, the absolute emission probabilities of the 258.4, 434.6 and 1768.3 keV gamma-ray from decay of (138)Xe were determined to be 34.9(10)%, 22.2(6)% and 18.8(5)%, respectively. PMID:23827509

Xie, Feng; Jiang, Wengang; He, Xiaobing; Li, Xuesong; Cheng, Zhanyin; Wang, Shilian; Li, Qi; Shi, Quanlin; Chang, Yongfu

2013-10-01

405

Changing methodology for measuring airborne radioactive discharges from nuclear facilities  

International Nuclear Information System (INIS)

The US Environmental Protection Agency (USEPA) requires that measurements of airborne radioactive discharges from nuclear facilities be performed following outdated methods contained in the American National Standards Institute (ANSI) N13.1-1969 Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities. Improved methods are being introduced via two paths. First, the ANSI standard is being revised, and second, EPA's equivalency granting process is being used to implement new technology on a case-by-case or broad basis. The ANSI standard is being revised by a working group under the auspices of the Health Physics Society Standards Committee. The revised standard includes updated methods based on current technology and a performance-based approach to design. The performance-based standard will present new challenges, especially in the area of performance validation. Progress in revising the standard is discussed. The US Department of Energy recently received approval from the USEPA for an alternate approach to complying with air-sampling regulations. The alternate approach is similar to the revised ANSI standard. New design tools include new types of sample extraction probes and a model for estimating line-losses for particles and radioiodine. Wind tunnel tests are being performed on various sample extraction probes for use at small stacks. The data show that single-point sampling probes are superior to ANSI-Nl3.1-1969 style multiple-point sample extraction probes

406

Fire protection measures in a repository for radioactive wastes  

International Nuclear Information System (INIS)

For the operational phase of a repository for radioactive wastes an incident analysis has to be performed which includes possible fire events in the plant. The procedure and the fire protection measures which have to be taken are described for the planned Konrad repository where it is intended to dispose of radioactive wastes with negligible thermal influence on the surrounding rock. A fire analysis was performed for the surface and underground facilities of the repository, especially for those parts of the facility where waste packages are handled. The occurrence of fire was investigated, the thermal loads determined and the fire detection and fire fighting measures established. Examples of the realization of fire protection measures in the design of the surface facilities in order to prevent internal fire and the burning of a vehicle are given. A waste repository in a deep geological formation such as the planned Konrad repository reveals the special precautions which have to be determined, especially in the underground facility where fires are more difficult to deal with than fires in surface facilities. As a consequence of the experience gained with fire events in the underground facilities of mines, burning of a vehicle during the transport of waste packages is the only fire event which leads to release of activity from the waste packages. Within the framework of incident analysis the thermal influence on the waste packages resulting from the fire event describedes resulting from the fire event described above was determined with the aid of a load function in the form of a temperature-time function (model curve). The effects resulting from this function were calculated. (author). 4 refs, 5 figs

407

Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility  

Science.gov (United States)

The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.

Deur, Alexandre

1999-10-01

408

Situation of radioactive wastes and their prevention and treatment measures in China's uranium mining and metallurgy  

International Nuclear Information System (INIS)

The sorts of radioactive wastes produced in uranium mining and metallurgy and their hazards are discribed in this paper. The characteristics of the radioactive wastes are discussed. The measurements and results are introduced for treatment and disposal of the radioactive wastes. The way to deal with prevention and treatment of radioactive wastes is presented in the stages of engineering design, construction, production and decommission of uranium mines and plants

409

Measurement of absolute response functions and detection efficiencies of an NE213 scintillator up to 600 MeV  

Science.gov (United States)

Absolute neutron response functions and detection efficiencies of an NE213 liquid scintillator that was 12.7 cm in diameter and 12.7 cm in thickness were measured for neutron energies between 15 and 600 MeV at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. The experiment was performed with continuous-energy neutrons on a spallation neutron source by 800-MeV proton incidence. The incident neutron flux was measured using a 238U fission ionization chamber. Measured response functions and detection efficiencies were compared with corresponding calculations using the SCINFUL-QMD code. The calculated and experimental values were in good agreement for data below 70 MeV. However, there were discrepancies in the energy region between 70 and 150 MeV. Thus, the code was partly modified and the revised code provided better agreement with the experimental data.

Kajimoto, Tsuyoshi; Shigyo, Nobuhiro; Sanami, Toshiya; Ishibashi, Kenji; Haight, Robert C.; Fotiades, Nikolaos

2011-02-01

410

Measurement of absolute intensity of 1001 keV gamma-ray of 234mPa  

International Nuclear Information System (INIS)

The 1001 keV ?-ray emission from 234mPa as an analytical peak has ever increasing importance in direct ?-ray spectrometric measurements of 238U content in samples with the development of high pure Ge detectors of larger crystal volumes and higher efficiency. ?-ray spectrometric measurement for the determination of the absolute intensity, P?, of 1001 keV ?-rays of 234mPa was carried out using powdered uranium samples and a new experimental value of 0.861 ± 0.015% for P? of the 1001 keV ?-ray of 234mPa has been obtained. The present measured value is greater than most of the recent experimental results and the newly recommended value of 0.835 ± 0.004% for P? by 2.5 to 4%. The present result differs from the latest experimental value of 0.92 ± 0.02% by 7%. (author)

411

Measurement of absolute response functions and detection efficiencies of an NE213 scintillator up to 600 MeV  

International Nuclear Information System (INIS)

Absolute neutron response functions and detection efficiencies of an NE213 liquid scintillator that was 12.7 cm in diameter and 12.7 cm in thickness were measured for neutron energies between 15 and 600 MeV at the Weapons Neutron Research facility of the Los Alamos Neutron Science Center. The experiment was performed with continuous-energy neutrons on a spallation neutron source by 800-MeV proton incidence. The incident neutron flux was measured using a 238U fission ionization chamber. Measured response functions and detection efficiencies were compared with corresponding calculations using the SCINFUL-QMD code. The calculated and experimental values were in good agreement for data below 70 MeV. However, there were discrepancies in the energy region between 70 and 150 MeV. Thus, the code was partly modified and the revised code provided better agreement with the experimental data.

412

Measurements of absolute delayed neutron yield and group constants in the fast fission of {sup 235}U and {sup 237}Np  

Energy Technology Data Exchange (ETDEWEB)

The delayed neutron activity resulting from the fast induced fission of {sup 235}U and {sup 237}Np has been studied. The six-group decay constants, relative abundances, and absolute yield of delayed neutrons from fast fission of {sup 235}U and {sup 237}Np were measured using the Godiva IV fast assembly at the Los Alamos Critical Experiments Facility. The absolute yield measured for {sup 235}U was 0.0163 {+-} 0.0008 neutron/fission. This value compares very well with the well-established Keepin absolute yield of 0.0165 {+-} 0.0005. The absolute yield value measured for {sup 237}Np was 0.0126 {+-} 0.0007. The measured delayed neutron parameters for {sup 235}U are corroborated with period (e-folding time) versus reactivity calculations.

Loaiza, D.J.; Brunson, G.; Sanchez, R.; Butterfield, K. [Los Alamos National Lab., NM (United States)

1998-03-01

413

A new liquid scintillation counter for the absolute activity measurement of radionuclides  

International Nuclear Information System (INIS)

The detection efficiency of a scintillation counter can be deduced from the knowledge of the statistical distribution of the light emitted by the scintillator. When using traditional photomultiplier tubes (PMT), the resolution of the of photons' spectrum is limited by the multiplication factor of the first dynode. Even with a high-gain PMT, the resolution of the single electron peak is low and the spectrum analysis is difficult. This is no longer the case with a new kind of commercially available photodetector, the hybrid photomultiplier tube (HPMT) in which the mean number of information quanta created by one photoelectron is much greater than those created in a PMT. The photoelectron spectrum resolution is thus dramatically improved and it is possible to deduce the statistical distribution of the number of photons emitted by the scintillator. This paper describes the use of this new photodetector in a liquid scintillation counter, designed for the standardisation of pure beta and electron capture radioactive solutions. The spectrum deconvolution process used to deduce the detection efficiency of the counter is also described

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ZnS(Ag) coating layer thickness verification of one small scintillation cell for 222Rn/220Rn absolute measurement  

International Nuclear Information System (INIS)

The detection efficiency of one small scintillation cell for 222Rn/220Rn absolute measurement can be affected by ZnS (Ag) coating layer thickness on the inner wall of the small scintillation cell. The ? detection efficiency of 10 mg/cm2 thickness ZnS (Ag) coating layer has been tested and verified using a plating reference source (241 Am). The solid angle correction factor is calculated by analysis and MCNP simulation methods. The absorption correction of air layer on ? particle has been discussed. The source of uncertainty has been analysed. The results indicate the ? detection efficiency of 10 mg/cm2 thickness ZnS (Ag) coating layer is between 102.4%-103.1% while the uncertainty is less than 5.44%. In the uncertain range ? detection efficiency of it is considered as 100%. 10 mg/cm2 thickness ZnS (Ag) coating layer can be used to apply on the inner wall of the small scintillation cell for 222Rn/220Rn absolute measurement. (authors)

415

Measurements of whole-body radioactivity in the UK population  

International Nuclear Information System (INIS)

A national survey of whole-body radioactivity was undertaken. A mobile whole-body counter visited collaborating Medical Physics Departments and Hospitals in England and Wales. Data were also obtained from an installed whole-body counter at the West Cumberland Hospital, Whitehaven, and from a control site at Addenbrooke's Hospital, Cambridge. 1657 volunteer members of the public were measured, including 162 children. 36% of volunteers had been measured in a similar survey 2 years earlier, and showed between a two and five fold reduction in body radiocaesium. No radiocaesium was detected in 54% of people measured. Measurements showed a progressive fall over the course of the study, reaching a baseline of 0.3 Bq137Cs/gK. In 1989, the additional radiation dose incurred from radiocaesium varied from a maximum of 4.1 ?Sv in Cumbria to 1.5 ?Sv in the South East, compared with the average annual radiation dose of 2500 ?Sv due to all other causes. No other gamma-emitting radionuclides were found. Results are consistent with Chernobyl as the source of the radiocaesium detected. (author)