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Sample records for alpha emitters critical

  1. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ( 211 At) and natural bismuth-212 ( 212 Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ( 223 Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  2. Production of alpha emitters for therapy

    International Nuclear Information System (INIS)

    Vucina, J.; Orlic, M.; Lukic, D.

    2006-01-01

    The basis for the introduction of alpha emitters into nuclear medical practice are their radiobiological properties. High LET values and short ranges in biological tissues are advantageous in comparison with nowadays most often used beta emitters, primarily 90 Y and 131 I. Given are the most important criteria for the introduction of a given radionuclide in the routine use. Shown are the procedures for the production of the most important alpha emitters 211 At, 212 Bi and 213 Bi. (author)

  3. Alpha-emitters for medical therapy workshop

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; McClure, J.J.

    1996-01-01

    A workshop on ''Alpha-Emitters for Medical Therapy'' was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference

  4. Alpha-emitters for medical therapy workshop

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E.; McClure, J.J.

    1996-12-31

    A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.

  5. Cancer therapy with alpha-emitters labeled peptides.

    Science.gov (United States)

    Dadachova, Ekaterina

    2010-05-01

    Actively targeted alpha-particles offer specific tumor cell killing action with less collateral damage to surrounding normal tissues than beta-emitters. During the last decade, radiolabeled peptides that bind to different receptors on the tumors have been investigated as potential therapeutic agents both in the preclinical and clinical settings. Advantages of radiolabeled peptides over antibodies include relatively straightforward chemical synthesis, versatility, easier radiolabeling, rapid clearance from the circulation, faster penetration and more uniform distribution into tissues, and less immunogenicity. Rapid internalization of the radiolabeled peptides with equally rapid re-expression of the cell surface target is a highly desirable property that enhances the total delivery of these radionuclides into malignant sites. Peptides, such as octreotide, alpha-melanocyte-stimulating hormone analogues, arginine-glycine-aspartic acid-containing peptides, bombesin derivatives, and others may all be feasible for use with alpha-emitters. The on-going preclinical work has primarily concentrated on octreotide and octreotate analogues labeled with Bismuth-213 and Astatine-211. In addition, alpha-melanocyte-stimulating hormone analogue has been labeled with Lead-212/Bismuth-212 in vivo generator and demonstrated the encouraging therapeutic efficacy in treatment of experimental melanoma. Obstacles that continue to obstruct widespread acceptance of alpha-emitter-labeled peptides are primarily the supply of these radionuclides and concerns about potential kidney toxicity. New sources and methods for production of these medically valuable radionuclides and better understanding of mechanisms related to the peptide renal uptake and clearance should speed up the introduction of alpha-emitter-labeled peptides into the clinic. Copyright 2010 Elsevier Inc. All rights reserved.

  6. Interactive session: alpha emitters, fashion or reality? radionuclides and molecules availability

    International Nuclear Information System (INIS)

    Zimmermann, R.

    2015-01-01

    Full text of publication follows. This introduction to the interactive session will simply be based on statements related to the future of therapy in nuclear medicine with some emphasis on the use of alpha-emitters. Some hypotheses will be developed on topics such as 'How will look nuclear medicine in 2025?', 'Do we have enough information to support the use of alpha in therapy?' 'Does it make sense to develop alpha-labelled molecules without long term financial commitment?', 'Will sufficient amounts of radionuclides available when the drugs will be ready for marketing?', 'Do we know enough about alpha emitters toxicity?', 'Is personalized medicine really the solution of the future of health care?', 'How can we convince authorities about the advantages of alpha labelled molecules?', 'Is the development of alpha RIT more expensive or more difficult than beta RIT?', 'Where are all the beta-emitter under development gone?', 'With alpha-emitters, are we speaking about 2025 or 2050?', 'Will Xofigo be a success?', 'What will be the real role of pharmaceutical companies in radiotherapy?', 'Who are the most afraid about radioactivity, the patients or the authorities?'. The speaker will provide his own opinion about each topic. Will you agree or not with him? What is your opinion? (author)

  7. Method validation to determine total alpha beta emitters in water samples using LSC

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Nashawati, A.; Al-akel, B.; Saaid, S.

    2006-06-01

    In this work a method was validated to determine gross alpha and beta emitters in water samples using liquid scintillation counter. 200 ml of water from each sample were evaporated to 20 ml and 8 ml of them were mixed with 12 ml of the suitable cocktail to be measured by liquid scintillation counter Wallac Winspectral 1414. The lower detection limit by this method (LDL) was 0.33 DPM for total alpha emitters and 1.3 DPM for total beta emitters. and the reproducibility limit was (± 2.32 DPM) and (±1.41 DPM) for total alpha and beta emitters respectively, and the repeatability limit was (±2.19 DPM) and (±1.11 DPM) for total alpha and beta emitters respectively. The method is easy and fast because of the simple preparation steps and the large number of samples that can be measured at the same time. In addition, many real samples and standard samples were analyzed by the method and showed accurate results so it was concluded that the method can be used with various water samples. (author)

  8. Preliminary studies for the determination of alpha emitters using the gross alpha coprecipitation methods

    International Nuclear Information System (INIS)

    Suarez-Navarro, J. A.; Pujol, L.; Suarez, J. A.; Pablo, M. A. de

    2003-01-01

    The radiological quality of drinking water in Spain is regulated by Nuclear Security Guideline No, 7.7 (Rev.1) of the Nuclear Security Council (NSC). this guideline establishes the protocol to follow when the radiological level exceeds 0,1 Bq.l''1. When this level is passed, the responsible alpha emitter must be identified; ''210 Po, ''226Ra, ''230Th, ''239Pu, ''224Ra, ''234 U and ''138 U. Activity due to these isotopes is usually determined using alpha spectrometry with semiconductor detectors. This method allows the activity of the alpha emitters to be determined with a good sensitivity. however, it requires long radiochemical isolations and long counting times, so the method is not suitable for rough estimate radiological analysis. In this preliminary work, we present the conditioning of the sample-precipitate that is essential for further radiochemical isolations. (Author) 9 refs

  9. Galex Lyman-alpha Emitters: Physical Properties, Luminosity Bimodality, And Morphologies.

    Science.gov (United States)

    Mallery, Ryan P.

    2010-01-01

    The Galaxy Evolution Explorer spectroscopic survey has uncovered a large statistically significant sample of Lyman-alpha emitters at z sim0.3. ACS imaging of these sources in the COSMOS and AEGIS deep fields reveals that these Lyman-alpha emitters consist of two distinct galaxy morphologies, face on spiral galaxies and compact starburst/merging systems. The morphology bimodality also results in a bimodal distribution of optical luminosity. A comparison between the UV photometry and MIPS 24 micron detections of these sources indicates that they are bluer, and have less dust extinction than similar star forming galaxies that lack Lyman-alpha detection. Our findings show how the global gas and dust distribution of star forming galaxies inhibits Lyman-alpha emission in star forming galaxies. GALEX is a NASA Small Explorer, launched in April 2003. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the CNES of France and the Korean Ministry of Science and Technology.

  10. Prolixe-prototype reprocessing unit for irradiating wastes contamined with alpha emitters

    International Nuclear Information System (INIS)

    Madic, C.; Sontag, R.

    1987-01-01

    A large number of hot cells are employed for research on nuclear fuel reprocessing and the production of isotope of transuranium elements. These activities generate solid wastes highly contaminated with alpha, beta, gamma emitters. The Prolixe hot cell was built in order to: 1/ reprocess the solid wastes contaminated with alpha, beta, gamma emitters produced in the Radiochemistry building: 2/ produce package wastes storable in shallow-ground disposal sites: 3/ develop a process sufficiently flexible to make it applicable to waste produced in other installations. The process is based on waste leaching after grinding. Depending on the type of wastes the leaching reactant will have a different composition 1/ nitric acid solution for cellulose waste: 2/ nitric solutions containing Ag(II) for other material. The complete process should achieve: 1/ a high waste volume reduction factor: 2/ the production of immobilized waste packages storage in shallow-ground disposal sites: 3/ the recycling of transuranium elements: 4/ the generation of a minimal volume of effluents. This process can be considered as an alternative process to incineration for the reprocessing of solid wastes highly contaminated with alpha, beta, gamma emitters

  11. Alpha spectrometry of thick sources. I. Application to alpha emitters determination

    International Nuclear Information System (INIS)

    Acena, M.L.; Garcia-Torano, E.; Rivero, M.C.

    1977-01-01

    A method for determining alpha emitters by silicon surface barrier detector spectroscopy using thick sources is studied. Two types of spectra have been obtained. They have different shapes of line according to the procedure used for preparing the sources. For both spectra a computing least square programme has been developed. In this way it is possible to calculate line intensities with accuracy better than 20 percent. (author) [es

  12. Critical review for the determination of the minimum detectable activity (MDA) of alpha-emitter radionuclides in environmental samples

    International Nuclear Information System (INIS)

    Gasco, C.; Anton, M.P.

    1996-12-01

    Different criteria for the calculation of the Minimum Detectable Activity (MDA) of an alpha emitter in environmental levels are reviewed in this report. Practical examples of its application to previously analyzed samples are shown. The authors propose a criteria based on prior calculations that applies to the radiochemical activities performed in the laboratory. The calculation procedure has been discussed with scientist from other laboratories in order to establish a general criteria to calculate the MDA

  13. Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters

    International Nuclear Information System (INIS)

    Garcia, F.; Goncalves, M.; Duarte, S.B.; Tavares, O.A.P.

    2000-02-01

    Alpha-decay half-life for ground-state transitions of 174 even-even alpha emitters has been calculated from a simple, Gamow-like model in which the quadrupole deformation of the product nucleus (assumed to have an ellipsoidal shape) is taken into account. The assumption made is that before tunneling through a purely Coulomb potential barrier the two-body system oscillates isotropically, thus giving rise to an equivalent, average polar direction θ (referred to the symmetry axis of the ellipsoid) for alpha emission. It is shown that the experimental half-life data are much better reproduced by the present description than in the spherical-shaped approximation for the daughter nucleus. (author)

  14. Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, F. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas; Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencias y Tecnologia Nucleares (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria IRD/CNEN, Rio de Janeiro, RJ (Brazil); Duarte, S.B.; Tavares, O.A.P. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: sbd@cbpf.br

    2000-02-01

    Alpha-decay half-life for ground-state transitions of 174 even-even alpha emitters has been calculated from a simple, Gamow-like model in which the quadrupole deformation of the product nucleus (assumed to have an ellipsoidal shape) is taken into account. The assumption made is that before tunneling through a purely Coulomb potential barrier the two-body system oscillates isotropically, thus giving rise to an equivalent, average polar direction {theta} (referred to the symmetry axis of the ellipsoid) for alpha emission. It is shown that the experimental half-life data are much better reproduced by the present description than in the spherical-shaped approximation for the daughter nucleus. (author)

  15. Continuous monitoring for airborne alpha emitters in a dusty environment

    International Nuclear Information System (INIS)

    Seiler, F.A.; Newton, G.J.; Guilmette, R.A.

    1988-01-01

    Disposal of radioactive wastes in underground facilities requires continuous monitoring for airborne radioactive materials, both on the surface and underground. In addition to a natural background of nonradioactive and radioactive aerosols, there may be a sizeable dust contribution from ongoing work such as mining and vehicular traffic. In the monitoring of alpha-emitting radionuclides, these aerosols may lead to self-absorption in the source and a deterioration of the energy spectrum of the detected alpha particles. In this paper, the influence of a realistic background aerosol on the performance of an alpha monitoring system is evaluated theoretically. It is shown that depositing alpha emitters and background aerosol on a surface for counting leads rapidly to a considerable loss of counts, a deterioration of the alpha spectra, an eventual saturation of the count rates, and interference from the natural background of Rn daughters

  16. Criticality management organization in the alpha incinerator

    International Nuclear Information System (INIS)

    Devillard, D.; Thiebaut, C.; Poinso, J.Y.; Huin, M.

    2004-01-01

    The Valduc Research Center, which reports to the CEA's Military applications Division, generates solid wastes contaminated with alpha emitters in the operation of its installations. An incineration plant has been built to treat these contaminated wastes. Criticality risk prevention is based on limiting the mass of active material undergoing treatment in the facility. A balance is compiled continuously by calculating the difference between the mass of active material entering the facility and the mass leaving it. Due to measurement uncertainties, the balance must be zeroed periodically by cleaning and drainage of all the equipment and the absence of holdup in the components must be checked. (authors)

  17. Microdosimetry of monoclonal antibodies labeled with alpha emitters

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1986-01-01

    The recent discovery of new techniques for the production of monoclonal antibodies (MoAB) has opened up a number of potential new applications in cancer diagnosis and therapy. Monoclonal antibodies labeled with alpha-emitting radionuclides promise to be particularly effective therapeutic agents due to the efficient cell killing ability of highly ionizing, short-range alpha particle tracks localized at specific antigen sites within the tumor mass. For a radioimmunotherapy treatment plan to be effective, one must be able to estimate the absorbed radiation dose to both tumor cells and normal tissues in the body. However, conventional methods used in nuclear medicine for estimating absorbed doses and specific absorbed fractions for radiopharmaceuticals do not apply to alpha emitters owing to their short range and the large variations in the local distribution of energy at the cellular level that result. Microdosimetric techniques developed for assessment of the radiological effects of internally deposited transuranic radionuclides take into account the statistical aspects of alpha particle track structure, energy distribution patterns, and radionuclide distribution within tissues, and provide a means for determining the number and frequency of cells irradiated, the probability densities in specific energy, and the average dose delivered to cells of interest. These techniques can be applied to the study of radiation absorbed dose from alpha-labeled monoclonal antibodies. 16 references, 6 figures

  18. Optimization in the nuclear fuel cycle II: Concentration of alpha emitters in the air

    International Nuclear Information System (INIS)

    Pereira, W.S.; Silva, A.X.; Lopes, J.M.; Carmo, A.S.; Mello, C.R.; Fernandes, T.S.; Kelecom, A.

    2017-01-01

    Optimization is one of the bases of radioprotection and aims to move doses away from the dose limit that is the borderline of acceptable radiological risk. The work aims to use the monitoring of the concentration of alpha emitters in the air as a tool of the optimization process. We analyzed 27 sampling points of airborne alpha concentration in a nuclear fuel cycle facility. The monthly averages were considered statistically different, the highest in the month of February and the lowest in the month of August. All other months were found to have identical mean activity concentration values. Regarding the sampling points, the points with the highest averages were points 12, 15 and 9. These points were indicated for the beginning of the optimization process. Analysis of the production of the facility should be performed to verify possible correlations between production and concentration of alpha emitters in the air

  19. Measurement of Alpha Emitters Concentration in Imported Cigarettes

    International Nuclear Information System (INIS)

    Nasser Allah, Z.K.; Musa, W.A.; AL-Rawi, A.A.S.

    2011-01-01

    The aime of this study was to measured the alpha emitters concentration of (15) different kinds of imported cigarettes. the nuclear reaction used U-235(n, f) obtained by the bombardment of U-235 with thermal neutrons from (Am B e)neutron source with thermal flux of(5*10 3 n.cm -2 .s -1 ). The Results obtained showed the values of the Uranium concentration, and varies from (0.041 ppm) in five stares kind to (2.374ppm) in Machbeth (chocolate) 100's kind. All the result obtained are within the limit levels as given by UNSCAR data

  20. Discriminator setting and cocktail preparation for analysis of alpha and beta emitters in aqueous solution using liquid scintillation counter

    International Nuclear Information System (INIS)

    Zaini Hamzah; Masitah Alias; Zaharudin Ahmad

    2011-01-01

    Liquid scintillation counting (LSC) is not only being used to measure pure beta emitters, but it can be used to measure both alpha and beta emitters simultaneously. Measurement of alpha and beta emitters in aqueous solution is done using a single sample. For the sample preparation, colorless detergent or emulsifier was used to incorporate the water into an organic based scintillator to produce a clear homogeneous solution, since this is the best form to give the highest count rate and detection efficiency. The instrument also need some attention, where after calibration, the LSC was set for the discriminator level which is suitable for measurement of both alpha and beta radiations. In this study, the focus is on the development of the best scintillation cocktail and establishes the best discriminator setting. From this study the best proportion of scintillation cocktail is 2:4:4 for water, toluene, and Triton-N101 (emulsifier) respectively and the best discriminator setting for alpha and beta counting are 120. (author)

  1. Therapy with high LET Radioisotopes: Can sufficient levels of attractive Auger and alpha emitters be produced to make their use practical?

    International Nuclear Information System (INIS)

    Knapp, F.F. Jr.; Mirzadeh, S.; Stabin, M.; Brill, A.B.

    2005-01-01

    Because of localized energy deposition within a very small volume, cellular targeted therapy with high linear energy transfer (LET) Auger-electron and alpha-particle emitting radioisotopes is of great interest. While the energy deposition from alpha particles usually encompasses several cell diameters, the dose from Auger electrons is confined to a single cell. Two major challenges for broader use of Alpha and Auger emitters are the efficient and cost effective routine production of sufficient levels of these radioisotopes, and the availability of targeting molecules to which the radioisotopes can be attached for cellular delivery of sufficient levels of activity for effective therapy. Examples of several Alpha-and Auger-emitting radioisotopes of current interest are presented. Alpha- and Auger electron-emitting radioisotopes can be produced in accelerators (A) and nuclear reactors (R), and several alpha emitter congeners (i.e. thorium-229) can be obtained from uranium decay products. The challenge for reactor production, is the availability and exploitation of methods - other then the usual radiative (n,γ) production route which will provide no-carrier-added (nca) or the high specific activity radioisotopes of interest. The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes High LET radioisotopes of current interest which are in the initial stages of development and/or which demonstrate practical use in clinical trials include several alpha-emitters, in particular bismuth-213 - and also the actinium-225 parent - astatine-211 and bismuth-212. Extensive experimental studies have been reported with Auger iododeoxyuridine (IdUR) radiolabeled with the iodine-125 emitter-labeled. However, development of production

  2. Determination of substraces of alpha emitter elements in water

    International Nuclear Information System (INIS)

    Gascon, J.L.

    1990-01-01

    To determine alpha emitter elements in water by alpha spectrometry, it is necessary to use large volumes of samples, concentration techniq-ues and to separate the elements of interest. In this report a study is presented about two concentration techniques and the process of analysis. Firstly, the stages of concentration method by iron hydroxide coprecipitation were studied in order to improve the results. The combination of liquid-liquid extraction and ion exchange techniques was the best way. Secondly, the technique by adsorption on manganese dioxide was studied. To apply this technique it was necessary to develop analysis methods to separate uranium, thorium, plutonium, americium and radium. These methods were designed combining several techniques of separation: liquid-liquid extraction, liquid-solid extraction, ionic exchange and coprecipitation. After the analysis methods were developped the adsorption on manganese dioxide with artificial samples was studied in the laboratory. Finally, the method of adsorption on manganese dioxide was studied to determine uranium, thorium and radium in the drinking water of Madrid. (Author)

  3. Irradiation of bone lining cells from bone-seeking alpha-emitters

    International Nuclear Information System (INIS)

    Kruglikov, I.; Polig, E.

    1993-01-01

    The influence of bone remodeling and the non-uniform distribution of alpha-emitters on the hit statistics is discussed. It is shown that for the first generation of bone lining cells, bone remodeling decreases the probability of no hits to the nuclei of these cells whereas the randomness of the spatial distribution of nuclide increases this probability. For the subsequent generations bone remodeling as well as spatial distribution of nuclide increase the probability of no hits. The most conservative estimations for the variance of hits and probability of no hits, which are defined by the minimums of these values, are obtained. (orig.)

  4. Immuno-vectorization of radioelements emitters of alpha particles: a new therapy in cancerology

    International Nuclear Information System (INIS)

    Bourgeois, M.

    2007-05-01

    The radio-immunotherapy is an anti cancerous therapy which consists in vectorising with immuno-specific agents very radio toxic radioelements on tumors or in their environment to destroy them. The first part of this report presents the different characteristics of antibodies as well as their means of production under monoclonal shapes specifically steered against a tumoral antigen of interest. The second part of this report replaces the importance of the immunological vectors in the context of the nuclear medicine. It is notably described that the different methods which allow to radio-label the vector, as well as the different ways of optimization which were envisaged to improve the targeting of radioelements on a tumor. These different developments allow to define the potential place of the alpha radio-immunotherapy in treatments and so re-place the interest of the experimental part. If the radio-immunotherapy, using beta emitters isotopes as the 131 iodine or the 90 yttrium, is today current in anti cancerous therapy, it finds limits because of the disintegration characteristics of the isotopes it uses. Indeed, compared with alpha particles, the beta particles deposit less energy by unit of length in the crossed material.The experimental part of this report aims at studying the feasibility of the coupling between an immunological vector and an alpha emitter isotope.The different tests led on the bismuth 213, the bismuth 212, the lead 212 and the astatine 211 demonstrated that the fixation of these radionuclides was possible. This research theme is strengthened by the construction in Nantes of a cyclotron with high energy ( A.R.R.O.N.A.X.) and the optimization of the obtained promising results should allow a therapeutic use in oncology of the alpha radio-immunotherapy. (N.C.)

  5. Problems in radiological protection involving alpha emitters in bone

    International Nuclear Information System (INIS)

    Dolphin, G.W.

    1976-01-01

    Quantitative dose/effect relationships for humans exposed to α emitters can only be established from data on humans exposed to this type of radiation. The risk of bone sarcoma from exposure to plutonium-239 may be established from the data on the human cases exposed to radium-226 either by consideration of the radiation dose to the osteoprogenitor cells or by use of the average bone dose together with a modifying factor to take into account the greater toxicity of plutonium relative to radium. The relative toxicity can be evaluated from the data on osteosarcoma incidence in animals. Both methods of risk estimation are given and criticised in the paper. In future recommendations, ICRP will not use the critical organ concept and the late effects from α emitters deposited in organs other than the bone will have to be taken into account in setting maximum permissible annual intakes. The implications of this and other proposed changes in ICRP concepts are discussed. (orig.) [de

  6. Alpha particle emitters in cancer therapy: establishing the rationale and overcoming the difficulties

    International Nuclear Information System (INIS)

    Sgouros, G.

    1996-01-01

    rapidly accessible disease. Alpha particles will be most useful in situations in which targeting is rapid, killing of isolated single-cells is important and access to normal tissue is minimized. The latter may be achieved by intracavitary administration or by labeling an agent that does not reach normal tissues before the radionuclide has decayed below an acceptable level. Although alpha-particle emitters have shown promise in animal models, they have not been examined in patients. The decay of 212 Bi is accompanied by emission of high energy (2.6 MeV) photons which are difficult to shield; 211 At is cyclotron produced and of limited availability. The initial obstacles to the use of alpha-particle emitters for therapy are availability, handling and radiochemistry. These are being overcome with the introduction of new radionuclides and better radiochemistry. Bismuth-213, for example, is similar to Bi-212 in its alpha particle emissions but does not emit the highly energetic photon seen with Bi-212. Once the initial, logistical obstacles are surmounted, the dosimetry and normal tissue toxicity must be investigated

  7. Localization of alpha emitters by damage production in a thin film. Application to the study of alpha emitter diffusion in irradiated samples; Localisation des emetteurs alpha par creation de dommages dans un film mince. Application a l'etude de la diffusion des emetteurs alpha dans des echantillons irradies

    Energy Technology Data Exchange (ETDEWEB)

    Houdaille, B; Perrot, M [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    The process of recording {alpha} particles on cellulose nitrate films, called alpha-graphy, is applied to the study of the diffusion of {alpha}-emitting elements in irradiated alloys. The existence of diffusion is shown by attacking the film with concentrated caustic soda after exposition. The insensitivity of the recorder to {beta} {gamma} radiation emitted by the sample after passing in the reactor makes it possible to operate with long exposure times and to detect small diffusions. The concentration-penetration curves are drawn up after carrying out a densitometric analysis of the alpha-graphies. - As the cellulose nitrate is affected only by {alpha} particles of energies of between 0.5 and 4 MeV, it was first necessary to determine the yield of the recorder for {alpha} particles emitted by a thick source, i.e. whose energy varies between 0 and E{sub 0}, E{sub 0} being the energy of the alpha emitter. - The concentration C of the {alpha}-emitter, as a function of the optical density D of the alpha-graphy, and of the exposure time t is given by a simple relationship: C = D/at where a is an experimental constant determined by calibration. It depends on the nature of the cellulose nitrate, of the {alpha}-emitting element and of the alloy studied. (authors) [French] Le procede d'enregistrement des particules alpha sur film de nitrate de cellulose, ou alphagraphie, est applique a l'etude de la diffusion d'elements emetteurs alpha dans des alliages irradies. La diffusion est mise en evidence par une attaque du film de nitrate, apres exposition, dans de la soude concentree. L'insensibilite de l'enregistreur au rayonnement {beta} {gamma}, emis par l'echantillon apres son sejour en pile, permet d'operer sur de longs temps de pose et de detecter des diffusions faibles. Les courbes concentration - penetration sont etablies par exploitation densitometrique des alphagraphies. - Comme le nitrate de cellulose n'est impressionne que par des particules alpha dont l'energie est

  8. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    Directory of Open Access Journals (Sweden)

    Ernesto Amato

    2014-03-01

    Full Text Available We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'generalized radius', calculated as 3V/S, where V is the ellipsoid volume and S its surface. Radiation-specific parametric functions were obtained in order to calculate the absorbed fraction of a given radiation in a generic ellipsoidal volume. The dose from a generic radionuclide can be calculated through a process of summation and integration over the whole radionuclide emission spectrum, profitably implemented in an electronic spreadsheet. We compared the results of our analytical calculation approach with those obtained from the OLINDA/EXM computer software, finding a good agreement in a wide range of sphere radii, for the high-energy pure beta emitter 90Y, the commonly employed beta-gamma emitter 131I, and the pure alpha emitter 213Po. The generality of our approach makes it useful an easy to implement in clinical dosimetry calculations as well as in radiation safety estimations when doses from internal radionuclide uptake are to be taken into account.

  9. Critical activities of α- and β-emitters in the environment

    International Nuclear Information System (INIS)

    Kanapickas, A.; Raupeliene, V.

    2003-01-01

    Environmental analysis of α-emitting radionuclides, such as 137 Cs, is relatively easily carried out, whereas the analysis of the β-emitters 90 Sr, 14 C or even 3 H and the α-emitting isotopes, such as Pu or Am is more complicated. Many of the currently used methods are well suitable for investigations of the environmental behavior of different radionuclides or in analyses of a radioactive fallout. However, the sample pretreatment and a radiochemical separation procedure is generally time-consuming and labor intensive. There is a lack of simple and rapid radioanalytic methods suitable in urgent situations when large amounts of samples have to be processed, such as shortly after a nuclear accident. On the other hand, the detection limits shortly after an accident do not necessarily have to be very low, but have to be clarified if any actions have to be taken. Increased detection limits could allow developing more simple and rapid methods. The required detection limits can be derived from the critical activity concentrations in different environmental materials that would require actions to be taken. However, there are lack of information for critical limits for α- and β-emitters, particularly, 90 Sr, Pu and Am, applicable to the cafe of a nuclear accident. In this work the critical activity concentrations in soil and pasture vegetation that would be required to exceed the action levels for foodstuffs is estimated. Since the action levels recommended by the IAEA are higher than those stated in Lithuanian Hygiene standard HN 54-1998 the latter values are taken as a guide in this study. The results show that if the aim of the analysis is to determine whether or not the action levels will be exceeded the common detection limits for the environmental analysis of α- and β-emitters may be increased at least by two orders of magnitude. In addition to activity concentrations, the critical deposition densities on soil and grazing areas are estimated. Critical limits

  10. Mechanisms of alpha emitter production in 12C induced reactions at 1 GeV

    International Nuclear Information System (INIS)

    Dufour, J.P.; Delagrange, H.; Del Moral, R.

    1982-01-01

    We present cross sections, mean projected recoil ranges and angular distributions of radioactive alpha emitters produced in 12 C-induced reactions at 1 GeV on targets ranging from Gd to Pb. We use a new technique of on-line electrostatic collection. The wide spectrum of produced isotopes corresponds to nuclei close to the target up to nuclei with as much as 60 nucleons less than the target. The intranuclear cascade calculations can reproduce the main features of nuclei having lost up

  11. The influence of nonuniform micro-distribution of alpha emitter on microdosimetry in cells

    International Nuclear Information System (INIS)

    Tian Yuan; Zhang Liang'an; Dai Guangfu

    2007-01-01

    Objective: To study the influence of nonuniform micro-distribution of alpha emitter on cellular S values(in the radioimmunotherapy). Methods: Emission of alpha particles is randomly simulated by Monte Carlo method; the incident energy and exit energy are calculated with interpolation technique based on the relationship between range and energy of alpha particle and the analytical Continuous Slowing Down Approximation (CSDA) model. So energy deposited in the target area can be obtained. To take 213 Po as an example, cellular S values with various cell dimensions and possible micro-distributions of radioactivity are calculated, such as linear increase, linear decrease, exponential increase and exponential decrease. Results: S values from cell to cell of uniform distribution showed no difference with the Hamacher's results. S values of different micro-distributions are distinguishing with each other. It is indicated that different micro-distributions of radioactivity will result in significant change of average chord length of alpha particles traveling in the target area, as well as the change of average stopping power over the chord, which is primary reason for differences of S values. Conclusions: The nonuniform micro-distributions show remarkable influence on cellular S values and hence should be taken consideration in cellular absorbed dose estimation, especially in microdosimetry. (authors)

  12. Treatment of solid waste highly contaiminated by alpha emitters

    International Nuclear Information System (INIS)

    Madic, C.; Breschet, C.; Vigreux, B.

    1990-01-01

    In the recent years, efforts have been made in order to reduce the amount of alpha emitters essentially plutonium isotopes present in the solid wastes produced either during research experiments on fuel reprocessing, done in the Radiochemistry building in the centre d'etudes nucleaires de FONTENAY-AUX-ROSES (CEA, FRANCE), or in the MARCOULE reprocessing plant (COGEMA, FRANCE). The goals defined for the treatments of these different wastes were: to reduce their α and β, Y contamination levels; to recover the plutonium, a highly valuable material, and to minimize its quantity to be discharged with the wastes. To achieve these goals leaching processes using electrogenerated Ag (II(a very aggressive agent for PuO 2 )) in nitric acid solutions, were developed and several facilities were designed and built to operate the processes. A brief description of the process and of the different facilities will be presented in this paper; the main results obtained in ELISE and PROLIXE are also summarized

  13. Reference sources for the calibration of surface contamination monitors - Beta-emitters (maximum beta energy greater than MeV) and alpha-emitters (International Standard Publication ISO 8769:1988)

    International Nuclear Information System (INIS)

    Stefanik, J.

    2001-01-01

    This International Standard specifies the characteristics of reference sources of radioactive surface contamination, traceable to national measurement standards, for the calibration of surface contamination monitors. This International Standard relates to alpha-emitters and to beta-emitters of maximum beta energy greater than 0,15 MeV. It does not describe the procedures involved in the use of these reference sources for the calibration of surface contamination monitors. Such procedures are specified in IEC Publication 325 and other documents. This International Standard specifies reference radiations for the calibration of surface contamination monitors which take the form of adequately characterized large area sources specified, without exception, in terms of activity and surface emission rate, the evaluation of these quantities being traceable to national standards

  14. Treatment of solid waste highly contaminated by alpha emitters

    International Nuclear Information System (INIS)

    Madic, C.; Breschet, C.; Vigreaux, B.

    1990-01-01

    In the recent years, efforts have been made in order to reduce the amount of alpha emitters essentially plutonium isotopes present in the solid wastes produced either during research experiments on fuel reprocessing, done in the Radiochemistry building in the centre d'etudes nuclearires de FONTENAY-AUX-ROSES (CEA, FRANCE), or in the MARCOULE reprocessing plant (COGEMA, FRANCE). The goals defined for the treatments of these different wastes were: to reduce their α and β, γ, contamination levels. and to recover the plutonium, an highly valuable material, and to minimize its quantity to be discharged with the wastes. To achieve these goals leaching processes using electrogenerated Ag (II (a very aggressive agent for PuO 2 )) in nitric acid solutions, were developed and several facilities were designed and built to operate the processes: ELISE and PROLIXE facilities: PILOT ASHES FACILITY for delete, the treatment of plutonium contaminated ashes (COGEMA, MARCOULE). A brief description of the process and of the different facilities will be presented in this paper; the main results obtained in ELISE and PROLIXE are also summarized

  15. Are the brightest Lyman Alpha Emitters at z=5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Jones, Heath; Meisenheimer, Klaus; Pompei, Emanuela; Tapken, Christian; Vanzi, Leonardo; Westra, Eduard

    2008-03-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line, the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at z=6.96, was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as the galaxies discovered through broad band drop out techniques, and, perhaps, more importantly, what role do LAEs play in re-ionising the universe. We recently discovered two extremely luminous LAEs at z=5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. the brightest LAEs are associated to the most massive halos. We propose to use the IRAC 3.6 micron imager on Spitzer to measure the rest-frame optical flux of the these LAEs. With additional data from the near-IR (rest-frame UV) and very deep optical spectra around the Lyman alpha line, we propose to make a detailed study of the spectral energy distribution from the Lyman alpha line to the rest frame optical of these exceptional LAEs. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population, if any, and to estimate the fraction of Lyman continuum photons that can escape the galaxy and are thus available to reionise the universe.

  16. Preliminary study on the analysis of alpha emitters at working places in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hanna; Kim, Jeong In; Lee, Byoungil [Korea Hydro and Nuclear Power Co., Seoul (Korea, Republic of); Yoon, Suk Won [Korea Institute of Radiological and Medical Sciences National Radiation Emergency Medical Center, Seoul (Korea, Republic of)

    2012-10-15

    Over sea nuclear power plants have been reported cases of internal contamination by alpha nuclides. In many cases, stations encountered significant alpha contamination when aged/legacy equipment was disturbed or handled. Under normal operating conditions, transuranic radionuclides are contained within the fuel rods and therefore are not a contributor to radioactive contamination within a facility. However, transuranic radionuclides result from the presence of tramp-uranium contamination on the exterior of fuel elements. Fuel failures may develop during operating cycles due to a variety of causes, ranging from manufacturing defects to mechanical or abrasive damage. In case of domestic nuclear power plants, the pressure tube replacements in Wolsong Unit 1 and steam generator replacements in Kori Unit 1 were done. Due to deterioration of equipment in accordance with the long-term operation, the domestic nuclear power plants are expected to improve the facilities and the probability of internal exposure from alpha emitters is increasing. The domestic nuclear power plants are only keeping alpha radionuclides of the effluent from the exterior under constant surveillance. The representative areas of CV are just carried out continuous alpha monitoring in during a unit outage. So far, there is no other case with alpha nuclides analysis. As the domestic nuclear power plants are expected to improve the facilities, it is the time to take proactive measures to deal with internal contamination by alpha emitting radioactive elements. In this paper, the possible risk of internal exposure is based on preliminary experiments on the analysis of alpha emitting radioactive elements at working places in nuclear power plants.

  17. Treatment of solid waste highly contaminated by alpha emitters: Recent developments of leaching process with continuous electrolyte regeneration

    International Nuclear Information System (INIS)

    Madic, C.; Lecomte, M.; Vigreux, B.

    1990-01-01

    Development of processes for leaching solid waste contaminated by alpha or alphaβgamma emitters has been pursued at the Nuclear Research Center in Fontenay-aux-Roses, France with the recent active commissioning of two pilot facilities: the Elise glove box system in February 1987 and the Prolixe shielded hot cell in March 1988. The Elise facility is designed to handle alpha waste and the Prolixe facility is designed to handle alphaβgamma waste. The common goal of the studies conducted in these facilities is to define the operating conditions for declassification of solid waste, i.e. to ensure that the alpha concentration of this waste will be less than 3.7 x 10 6 Bq/kg after treatment, packaging and decay prior to storage in surface repositories. The leaching process developed is mainly based on the continuous electrolytic regeneration of an aggressive agent, AgII, which can induce the dissolution of PuO 2 , the most difficult compound to remove from the solid waste. This paper summarizes recent achievements in the development of this process. 11 refs., 8 figs., 6 tabs

  18. Treatment of solid waste highly contaminated by alpha emitters: recent developments of leaching process with continuous electrolyte regeneration

    International Nuclear Information System (INIS)

    Madic, C.; Lecomte, M.

    1990-01-01

    Development of processes for leaching solid waste contaminated by alpha or alpha/beta/gamma emitters has been pursued at the Nuclear Research Center in Fontenay-aux-Roses, France with the recent active commissioning of two pilot facilities: the Elise glove box system in February 1987 and the Prolixe shielded hot cell in March 1988. The Elise facility is designed to handle alpha waste and the Prolixe facility is designed to handle alpha/beta/gamma waste. The common goal of the studies conducted in these facilities is to define the operating conditions for declassification of solid waste, i.e. to ensure that the alpha concentration of this waste will be less than 3.7 x 10 6 Bq/kg after treatment, packaging and decay prior to storage in surface repositories. The leaching process developed is mainly based on the continuous electrolytic regeneration of an aggressive agent, AgII, which can induce the dissolution of PuO 2 , the most difficult compound to remove from the solid waste. This paper summarizes recent achievements in the development of this process

  19. Radiological hazards of alpha-contaminated waste

    International Nuclear Information System (INIS)

    Rodgers, J.C.

    1982-01-01

    The radiological hazards of alpha-contaminated wastes are discussed in this overview in terms of two components of hazard: radiobiological hazard, and radioecological hazard. Radiobiological hazard refers to human uptake of alpha-emitters by inhalation and ingestion, and the resultant dose to critical organs of the body. Radioecological hazard refers to the processes of release from buried wastes, transport in the environment, and translocation to man through the food chain. Besides detailing the sources and magnitude of hazards, this brief review identifies the uncertainties in their estimation, and implications for the regulatory process

  20. Early bone changes after incorporation of low quantities of alpha emitters in male rats

    International Nuclear Information System (INIS)

    Laengle, U.W.

    1988-09-01

    This work shows the early effects of cancergenic doses of alpha emitters in long bones of rats. The investigations were based on radiographic, morphologic, angiographic, histologic and electronmicroscopic methods. A special method for bone angiography in the rat was elaborated and a new method was developed for measurement of the femur neck-head angle. Numerous disturbances in bone growth and bone structure, in the blood supply of bone and also of the bone building cells were observed. There was a correlation between the severity of the damage and the radiation dose, the spacial distribution of the nuclide and partially the age of the rats. The bone injury due to plutonium was markedly reduced by administration of the chelating agent Zn-DTPA. (orig.) [de

  1. Treatment of solid waste highly contaminated by alpha emitters: Low-temperature impact crushing, leaching and incineration

    International Nuclear Information System (INIS)

    Bertolotti, G.; Vigreux, B.; Caillol, A.; Koehly, G.

    1987-01-01

    Reprocessing plants, hot laboratories and fuel fabrication plants produce solid wastes containing residual amounts of plutonium and uranium in nitrate and oxide form at concentrations up to several tens of grams per m/sup 3/. Dismantling of nuclear facilities having handled these radioelements also generates large volumes of solid wastes highly contaminated with alpha emitters. It is desirable to process these alpha wastes to recover valuable fissile materials and/or permit surface storage. Solid waste treatment by low-temperature impact crushing and then leaching, after minimal sorting and classifying at the sites of production, meets the corresponding requirements for high volume reduction plus fissile material recovery or waste decontamination. Additional volume reduction of crushed wastes containing mainly combustible materials can be obtained by incineration. This is facilitated by the low fissile material content after low-temperature impact crushing and leaching. Sorted wastes can also be leached or incinerated directly after, in most cases, crushing by more conventional techniques

  2. AVERAGE METALLICITY AND STAR FORMATION RATE OF Ly{alpha} EMITTERS PROBED BY A TRIPLE NARROWBAND SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kimihiko; Shimasaku, Kazuhiro; Ono, Yoshiaki; Okamura, Sadanori [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ouchi, Masami [Institute for the Physics and Mathematics of the Universe (IPMU), TODIAS, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Lee, Janice C.; Ly, Chun [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Foucaud, Sebastien [Department of Earth Sciences, National Taiwan Normal University, No. 88, Tingzhou Road, Sec. 4, Taipei 11677, Taiwan (China); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY (United States); Salim, Samir [Department of Astronomy, Indiana University, Bloomington, IN (United States); Finn, Rose [Department of Physics, Siena College, Loudonville, NY (United States); Almaini, Omar, E-mail: nakajima@astron.s.u-tokyo.ac.jp [School of Physics and Astronomy, University of Nottingham, Nottingham (United Kingdom)

    2012-01-20

    We present the average metallicity and star formation rate (SFR) of Ly{alpha} emitters (LAEs) measured from our large-area survey with three narrowband (NB) filters covering the Ly{alpha}, [O II]{lambda}3727, and H{alpha}+[N II] lines of LAEs at z = 2.2. We select 919 z = 2.2 LAEs from Subaru/Suprime-Cam NB data in conjunction with Magellan/IMACS spectroscopy. Of these LAEs, 561 and 105 are observed with KPNO/NEWFIRM near-infrared NB filters whose central wavelengths are matched to redshifted [O II] and H{alpha} nebular lines, respectively. By stacking the near-infrared images of the LAEs, we successfully obtain average nebular-line fluxes of LAEs, the majority of which are too faint to be identified individually by NB imaging or deep spectroscopy. The stacked object has an H{alpha} luminosity of 1.7 Multiplication-Sign 10{sup 42} erg s{sup -1} corresponding to an SFR of 14 M{sub Sun} yr{sup -1}. We place, for the first time, a firm lower limit to the average metallicity of LAEs of Z {approx}> 0.09 Z{sub Sun} (2{sigma}) based on the [O II]/(H{alpha}+[N II]) index together with photoionization models and empirical relations. This lower limit of metallicity rules out the hypothesis that LAEs, so far observed at z {approx} 2, are extremely metal-poor (Z < 2 Multiplication-Sign 10{sup -2} Z{sub Sun }) galaxies at the 4{sigma} level. This limit is higher than a simple extrapolation of the observed mass-metallicity relation of z {approx} 2 UV-selected galaxies toward lower masses (5 Multiplication-Sign 10{sup 8} M{sub Sun }), but roughly consistent with a recently proposed fundamental mass-metallicity relation when the LAEs' relatively low SFR is taken into account. The H{alpha} and Ly{alpha} luminosities of our NB-selected LAEs indicate that the escape fraction of Ly{alpha} photons is {approx}12%-30%, much higher than the values derived for other galaxy populations at z {approx} 2.

  3. PHYSICAL PROPERTIES OF Ly{alpha} EMITTERS AT z {approx} 0.3 FROM UV-TO-FIR MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Oteo, I.; Bongiovanni, A.; Perez Garcia, A. M.; Cepa, J.; Pintos-Castro, I. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Ederoclite, A. [Centro de Estudios de Fisica del Cosmos de Aragon, Plaza San Juan 1, Planta 2, Teruel, 44001 (Spain); Sanchez-Portal, M.; Altieri, B. [Herschel Science Centre (ESAC), Villafranca del Castillo (Spain); Perez-Martinez, R. [XMM/Newton Science Operations Centre (ESAC), Villafranca del Castillo (Spain); Lutz, D.; Berta, S.; Foerster Schreiber, N.; Genzel, R.; Magnelli, B. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, 85741 Garching (Germany); Andreani, P. [ESO, Karl-Schwarzchild-Str. 2, D-85748 Garching (Germany); Aussel, H.; Daddi, E.; Elbaz, D.; Le Floc' h, E. [Commissariat a l' Energie Atomique (CEA-SAp) Saclay (France); Cimatti, A. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy); and others

    2012-06-01

    The analysis of the physical properties of low-redshift Ly{alpha} emitters (LAEs) can provide clues in the study of their high-redshift analogs. At z {approx} 0.3, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this work, we examine the UV and IR emission, dust attenuation, star formation rate (SFR), and morphology of a sample of 23 GALEX-discovered star-forming LAEs at z {approx} 0.3 with direct UV (GALEX), optical (ACS), and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at z {approx} 0.3 tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Ly{alpha} emission in their spectrum (non-LAEs). These results suggest that at z {approx} 0.3, Ly{alpha} photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at z {approx} 0.3. Furthermore, the comparison of our results with those obtained at higher redshifts indicates either that the Ly{alpha} technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.

  4. GAS MOTION STUDY OF Ly{alpha} EMITTERS AT z {approx} 2 USING FUV AND OPTICAL SPECTRAL LINES {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko [Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Ouchi, Masami; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Rauch, Michael; Janice Lee [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Okamura, Sadanori, E-mail: thashimoto@astron.s.u-tokyo.ac.jp [Department of Advanced Sciences, Faculty of Science and Engineering, Hosei University, 3-7-2 Kajino-cho, Koganei-shi, Tokyo 184-8584 (Japan)

    2013-03-01

    We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Ly{alpha} emitters (LAEs) at z {approx_equal} 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including H{alpha} on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Ly{alpha} line, {Delta}v {sub Ly{alpha}}, and LIS absorption lines, {Delta}v {sub abs}, with respect to the systemic velocity defined by the nebular lines. For a sample of eight z {approx} 2-3 LAEs without active galactic nucleus from our study and the literature, we obtain {Delta}v {sub Ly{alpha}} = 175 {+-} 35 km s{sup -1}, which is significantly smaller than that of Lyman-break Galaxies (LBGs), {Delta}v {sub Ly{alpha}} {approx_equal} 400 km s{sup -1}. The stacked FUV spectrum gives {Delta}v {sub abs} = -179 {+-} 73 km s{sup -1}, comparable to that of LBGs. These positive {Delta}v {sub Ly{alpha}} and negative {Delta}v {sub abs} suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' {Delta}v {sub Ly{alpha}} is as small as |{Delta}v {sub abs}|, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Ly{alpha} emission of LAEs. We find an anti-correlation between Ly{alpha} equivalent width (EW) and {Delta}v {sub Ly{alpha}} in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small {Delta}v {sub Ly{alpha}} values, constraints on the reionization history derived from the Ly{alpha} transmissivity may need to be revised.

  5. Summary of alpha-neutron sources in GADRAS

    International Nuclear Information System (INIS)

    Mitchell, Dean James; Thoreson, Gregory G.; Harding, Lee T.

    2012-01-01

    A common source of neutrons for calibration and testing is alpha-neutron material, named for the alpha-neutron nuclear reaction that occurs within. This material contains a long-lived alpha-emitter and a lighter target element. When the alpha particle from the emitter is absorbed by the target, neutrons and gamma rays are released. Gamma Detector Response and Analysis Software (GADRAS) includes built-in alpha-neutron source definitions for AcC, AmB, AmBe, AmF, AmLi, CmC, and PuC. In addition, GADRAS users may create their own alpha-neutron sources by placing valid alpha-emitters and target elements in materials within their one-dimensional models (1DModel). GADRAS has the ability to use pre-built alpha-neutron sources for plotting or as trace-sources in 1D models. In addition, if any material (existing or user-defined) specified in a 1D model contains both an alpha emitter in conjunction with a target nuclide, or there is an interface between such materials, then the appropriate neutron-emission rate from the alpha-neutron reaction will be computed. The gamma-emissions from these sources are also computed, but are limited to a subset of nine target nuclides. If a user has experimental data to contribute to the alpha-neutron gamma emission database, it may be added directly or submitted to the GADRAS developers for inclusion. The gadras.exe.config file will be replaced when GADRAS updates are installed, so sending the information to the GADRAS developers is the preferred method for updating the database. This is also preferable because it enables other users to benefit from your efforts.

  6. DISSECTION OF H{alpha} EMITTERS : LOW-z ANALOGS OF z > 4 STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyunjin [Department of Earth Science Education, Kyungpook National University (Korea, Republic of); Chary, Ranga-Ram, E-mail: hjshim@knu.ac.kr [U.S. Planck Data Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States)

    2013-03-01

    Strong H{alpha} emitters (HAEs) dominate the z {approx} 4 Lyman-break galaxy (LBG) population. We have identified local analogs of these HAEs using the Sloan Digital Sky Survey. At z < 0.4, only 0.04% of the galaxies are classified as HAEs with H{alpha} equivalent widths ({approx}> 500 A) comparable to that of z {approx} 4 HAEs. Local HAEs have lower stellar mass and lower ultraviolet (UV) luminosity than z {approx} 4 HAEs, yet the H{alpha}-to-UV luminosity ratio, as well as their specific star formation rate, is consistent with that of z {approx} 4 HAEs, indicating that they are scaled-down versions of high-z star-forming galaxies. Compared to the previously studied local analogs of LBGs selected using rest-frame UV properties, local HAEs show similar UV luminosity surface density, weaker D{sub n} (4000) break, lower metallicity, and lower stellar mass. This implies that the local HAEs are less evolved galaxies than the traditional Lyman break analogs. In the stacked spectrum, local HAEs show a significant He II {lambda}4686 emission line suggesting a population of hot, massive stars similar to that seen in some Wolf-Rayet galaxies. Low [N II]/[O III] line flux ratios imply that local HAEs are inconsistent with being systems that host bright active galactic nuclei. Instead, it is highly likely that local HAEs are galaxies with an elevated ionization parameter, either due to a high electron density or large escape fraction of hydrogen ionizing photons as in the case of Wolf-Rayet galaxies.

  7. Are the brightest Lyman Alpha Emitters at zD5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Hayes, Matthew; Jones, Heath; Meisenheimer, Klaus; Tapken, Christian; Westra, Eduard

    2009-04-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line - the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at zD6.96 (Iye et al. 2006), was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as those discovered through drop out techniques, and, more importantly, what role LAEs play in re-ionising the universe, if any. We recently discovered two extremely luminous LAEs at zD5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. (2007), the brightest LAEs are associated to the most massive halos. One of these targets was successfully observed with the IRAC 3.6 micron imager on Spitzer during cycle 5. These data, when combined with constraints that we derive from our deep ground-based spectroscopic data, indicate that the bulk of the flux at 3.6 microns comes from a stellar population that is considserably older than the stars that dominate the flux in the UV. We propose to complete the project and image the second target. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population and to estimate the fraction of Lyman continuum photons that escape the galaxy and are thus available to re-ionise the universe.

  8. Transverse beam emittance optimization for the injection into BESSY II

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Felix [Helmholtz Zentrum Berlin, Institut Beschleunigerphysik (Germany); Humboldt-Universitaet zu Berlin, Institut fuer Physik (Germany)

    2016-07-01

    For top up injection into the storage ring BESSY II an average injection efficiency of at least 90% is required. In low alpha mode the injection efficiency does not meet the requirements. Future BESSY II features will include shorter bunches in the storage ring (VSR) and user transparent injection with a non linear kicker. These will raise the demands on the quality of the injected beam even further. This work investigates the development of transverse emittance over the acceleration cycle in the synchrotron and the possibility of transverse emittance exchange by a sequence of skew quadrupoles in the transfer line. Results of emittance measurements and emittance exchange simulations will be given.

  9. Intraperitoneal alpha-radioimmunotherapy in mice using different specific activities

    DEFF Research Database (Denmark)

    Elgqvist, Jörgen; Andersson, Håkan; Haglund, Elin

    2009-01-01

    The aim of this study was to investigate the therapeutic efficacy of the alpha-radioimmunotherapy of ovarian cancer in mice, using different specific activities. This study was performed by using the monoclonal antibody, MX35 F(ab')(2), labeled with the alpha-particle-emitter, 211At.......The aim of this study was to investigate the therapeutic efficacy of the alpha-radioimmunotherapy of ovarian cancer in mice, using different specific activities. This study was performed by using the monoclonal antibody, MX35 F(ab')(2), labeled with the alpha-particle-emitter, 211At....

  10. Cooperative spontaneous emission of nano-emitters with inter-emitter coupling in a leaky microcavity

    International Nuclear Information System (INIS)

    Hong, Suc-Kyoung; Nam, Seog Woo; Yang, Hyung Jin

    2015-01-01

    We study the spontaneous emission from a few two-level nano-emitters placed in a leaky microcavity with Lorentzian spectral density near a critically damped regime. Collective features of the spontaneous emission are investigated by numerical analysis of the excitation dynamics when initially one nano-emitter is totally excited but we do not know which one. The results show that there are three decay rates in the excitation dynamics, two for simple exponential decays and one for damped oscillatory decay. The excitation dynamics is found to critically depend on the regime of the system. It is shown that the spontaneous emission is enhanced or suppressed depending on whether the system is in the underdamped or overdamped regime, respectively. On the other hand, the cooperative spontaneous emission is suppressed in the underdamped while it is enhanced in the overdamped regime. Furthermore, the effect of the direct inter-emitter coupling on the breaking of the cooperativeness of the spontaneous emission is shown as well. (paper)

  11. Criteria for emittance compensation in high-brightness photoinjectors

    Directory of Open Access Journals (Sweden)

    Chun-xi Wang

    2007-10-01

    Full Text Available A critical process in high-brightness photoinjectors is emittance compensation, which brings under control the correlated transverse emittance growth due to the linear space-charge force. Although emittance compensation has been used and studied for almost two decades, the exact criteria to achieve emittance compensation is not as clear as it should be. In this paper, a perturbative analysis of slice envelopes and emittance evolution close to any reference envelope is developed, via which space-charge and chromatic effects are investigated. A new criterion for emittance compensation is found, which is complementary to the well-known matching condition for the invariant envelope and agrees very well with simulations.

  12. Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings

    Science.gov (United States)

    Chandrasekhar, Prasanna

    2011-01-01

    One of the last remaining technical hurdles with variable emittance devices or skins based on conducting polymer electrochromics is the high solar absorptance of their top surfaces. This high solar absorptance causes overheating of the skin when facing the Sun in space. Existing technologies such as mechanical louvers or loop heat pipes are virtually inapplicable to micro (solar absorption to Alpha(s) of between 0.30 and 0.46. Coupled with the emittance properties of the variable emittance skins, this lowers the surface temperature of the skins facing the Sun to between 30 and 60 C, which is much lower than previous results of 100 C, and is well within acceptable satellite operations ranges. The performance of this technology is better than that of current new technologies such as microelectromechanical systems (MEMS), electrostatics, and electrophoretics, especially in applications involving micro and nano spacecraft. The coatings are deposited inside a high vacuum, layering multiple coatings onto the top surfaces of variable emittance skins. They are completely transparent in the entire relevant infrared region (about 2 to 45 microns), but highly reflective in the visible-NIR (near infrared) region of relevance to solar absorptance.

  13. Determination of radium-226 in fresh water, using alpha spectroscopy

    International Nuclear Information System (INIS)

    Byrakdar, M. E.

    2006-12-01

    Four radium isotopes are present in nature, i.e. Ra-223, Ra-224, Ra-226, and Ra-228. The first three are alpha emitters while the last is a beta emitter. Because of the importance of the determination of Alpha isotope emitters in pure water (drinking water), this work focuses on the determination of radium-226 as it has the longest half-life (1600 years, in comparison to 11.4 day, 3.66 days for Ra-223 and Ra-224, respectively) using Alpha spectroscopy. This method has the capability to be applied in sampling fields and low detection limit which in turn makes the analysis of low-level radioactive environmental water samples, with hardness does not exceed 40 French Degree, satisfying for health and environment control programmes. However, counting the samples using Alpha spectroscopy has to be immediate (or within 48 hours). (author)

  14. ALPHA/AMPU, Radionuclide Radioactivity from Alpha Spectrometer Measurements

    International Nuclear Information System (INIS)

    Sill, D.S.

    1990-01-01

    1 - Description of program or function: The two computer programs, ALPHA and AMPU, take raw data obtained from alpha spectrometry and from these calculate activities and uncertainties of the radionuclides present in the sample. ALPHA determines activities of any alpha emitter in a sample that has been directly precipitated with NdF 3 . AMPU determines the Pu-239, Pu-238,and Am-241 activities using Pu-236 and Am-243 tracers. 2 - Method of solution: These programs propagate all random and systematic uncertainties, found anywhere in the experimental process, to the final result. The result is rounded and is in decimal agreement with the uncertainty. 3 - Restrictions on the complexity of the problem: In ALPHA, a chemical yield of 98% is assumed

  15. Optimization in the nuclear fuel cycle II: Concentration of alpha emitters in the air; Otimização no ciclo do combustível nuclear II: concentração de alfa emissores no ar

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, W.S., E-mail: pereiras@gmail.com [Universidade Veiga de Ameida (UVA), Rio de Janeiro, RJ (Brazil); Silva, A.X.; Lopes, J.M.; Carmo, A.S.; Mello, C.R.; Fernandes, T.S., E-mail: lararapls@hotmail.com, E-mail: Ademir@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Kelecom, A. [Universidade Federal Fluminense (UFF), Niterói, RJ (Brazil)

    2017-07-01

    Optimization is one of the bases of radioprotection and aims to move doses away from the dose limit that is the borderline of acceptable radiological risk. The work aims to use the monitoring of the concentration of alpha emitters in the air as a tool of the optimization process. We analyzed 27 sampling points of airborne alpha concentration in a nuclear fuel cycle facility. The monthly averages were considered statistically different, the highest in the month of February and the lowest in the month of August. All other months were found to have identical mean activity concentration values. Regarding the sampling points, the points with the highest averages were points 12, 15 and 9. These points were indicated for the beginning of the optimization process. Analysis of the production of the facility should be performed to verify possible correlations between production and concentration of alpha emitters in the air.

  16. Fetal dosimetry from natural alpha emitters

    Energy Technology Data Exchange (ETDEWEB)

    Purnell, S.J

    1999-09-01

    The size of marrow cavities in fetal vertebra, rib and sternum was investigated using an image analysis system. The average chord lengths through marrow spaces in the vertebrae were found to increase approximately linearly with gestational age from 140 {mu}m at 20 weeks to 300 {mu}m at 40 weeks. Average chord lengths through marrow spaces in fetal rib and sternum were 330 {mu}m at 35 weeks in both cases. These results can be compared with an average chord length across marrow spaces in adult vertebra of 1172 {mu}m. At natural background UK exposure, activity concentrations of supported {sup 210}Po in fetal bone of 0.075 Bq kg{sup -1} and 0.15 Bq kg{sup -1} at mid- and late gestation respectively were calculated. Monte Carlo simulations modelling the paths of alpha-particles in fetal vertebra gave a total alpha-radiation dose to marrow over the second and third trimesters of 32.0 {+-} 0.8 {mu}Sv with the {sup 210}Po in bone contributing 8.9 {+-} 0.9 {mu}Sv. The dose to primitive haemopoietic stem cells, the target cells for acute lymphoblastic leukaemia, and the survival of these stem cells following a hit by an alpha-particle was investigated, also using Monte Carlo simulations. Alpha-particles emitted from bone and marrow contributed an average dose of 1.9 Gy to stem cells with a nuclear diameter of 3.8 {mu}m. This study has estimated that 1% of babies born each year are born with a mutated primitive haemopoietic stem cell due to in utero irradiation from high LET radiation. That is 7,320 babies compared to an estimated 300 incidences of cALL each year initiated in utero. The probability that a mutated cell will go on to give rise to leukaemia is unknown but it would seem not unlikely that irradiation in utero plays a substantial part in the induction of childhood leukaemia. (author)

  17. The used epoxy matrix in immobilization sludge process of alpha emitter radioactive waste

    International Nuclear Information System (INIS)

    Walman, E.; Salimin, Z.; Johan, B.

    1998-01-01

    Immobilization of alpha emitter radioactive waste containing of ion complex of uranyl carbonate on uranium concentration ≤ 50 mg/l has been carried out using epoxy matrix. The first step of process is the coagulation of uranium with 1.3 mole/l of Ca(OH) 2 coagulant concentration on pH 8 to precipitate the calcium uranyl carbonate on uranium concentration ≤ g/l. The immobilization of calcium uranyl carbonate with epoxy matrix was done on variation of the ratio of resin epoxy and hardener of 1 : 1 (giving the maximum value of density and compressive strength), the increasing of precipitate loading capacity give the decreasing of compressive strength of embedded waste. The test of compressive strength and leaching was done for the embedded waste after its curing time using Paul Weber equipment and 7 days immersion of samples in normal water. On the precipitate loading capacity of 70%, the quality of embedded waste still conform to the standard quality value i.e. density 1.2 g/cm 3 , compressive strength 10 kN/cm 2 and there is not any release of radionuclide during leaching test (undetectable).. (author)

  18. Dosimetry of internal emitters

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Dosimetry of Internal Emitter Program endeavors to refine the correlation between radiation dose and observed biological effects. The program is presently engaged in the development of studies that will demonstrate the applicability of microdosimetry models developed under the Microdosimetry of Internal Sources Program. The program also provides guidance and assistance to Pacific Northwest Laboratory's Biology Department in the dosimetric analysis of internally deposited radionuclides. This report deals with alpha particle dosimetry plutonium 239 inhalation, and in vitro studies of chromosomal observations

  19. Treatment of solid waste highly contaminated by alpha emitters. Recent developments of leaching process with continuous electrolyte regeneration

    International Nuclear Information System (INIS)

    Madic, C.

    1990-01-01

    In the recent years, efforts have been made in order to reduce the amount of alpha emitters essentially plutonium isotopes present in the solid wastes produced during research experiments on fuel reprocessing. Leaching processes using electrogenerated Ag (II(a very agressive agent for PuO 2 )) in nitric acid solutions, were developed and several facilities were designed and built to operate the processes: (1) ELISE and PROLIXE facilities, for the treatment of α and α, β, γ solid wastes (CEA, FONTENAY-AUX-ROSES) (2) PILOT ASHES FACILITY for delete, the treatment of plutonium contaminated ashes (COGEMA, MARCOULE). A brief description of the process and of the different facilities is presented; the main results obtained in ELISE and PROLIXE are also summarized

  20. Report of a Technical Meeting on ''Alpha emitting radionuclides and radiopharmaceuticals for therapy''

    International Nuclear Information System (INIS)

    2013-01-01

    Considering the high potential of α-emitters for future development of radionuclide therapy, the International Atomic Energy Agency (IAEA) organized a Technical Meeting on ‘Alpha Emitting Radionuclides and Radiopharmaceuticals for Therapy’, from June 24 to 28, 2013, at IAEA Headquarters in Vienna with the purpose of gathering eminent Experts in the field and discuss with them the status and future perspectives of the field. Sixteen Experts and two External Observers from ten different countries, and four IAEA Technical Officers attended this meeting. Outstanding lectures have been presented covering all relevant aspects of α-therapy, which were followed by extensive discussions and analysis. Selected arguments encompassed production methods and availability of alpha-emitting radionuclides, labelling chemistry of alpha-emittting radioelements, design and development of target-specific radiopharmaceuticals, physical principles of alpha-particle dosimetry and advanced dosimetric models, biological effects of alpha radiation at the cellular level, on-going preclinical and clinical studies with new radiopharmaceuticals, results of clinical trials on the use of radium-223 chloride solutions for the treatment of metastatic bone cancer. The broad scientific background of invited components of the Experts’ panel conferred a strong interdisciplinary trait to the overall discussion and stimulated a critical analysis of this emerging unexplored field. Results of this comprehensive overview on alpha therapy, including recommendations to the Agency on suitable initiatives that may help to promote and spread the knowledge to Members States on this emerging therapeutic modality, are summarized in the present Report

  1. Measuring Beam Sizes and Ultra-Small Electron Emittances Using an X-ray Pinhole Camera.

    Science.gov (United States)

    Elleaume, P; Fortgang, C; Penel, C; Tarazona, E

    1995-09-01

    A very simple pinhole camera set-up has been built to diagnose the electron beam emittance of the ESRF. The pinhole is placed in the air next to an Al window. An image is obtained with a CCD camera imaging a fluorescent screen. The emittance is deduced from the size of the image. The relationship between the measured beam size and the electron beam emittance depends upon the lattice functions alpha, beta and eta, the screen resolution, pinhole size and photon beam divergence. The set-up is capable of measuring emittances as low as 5 pm rad and is presently routinely used as both an electron beam imaging device and an emittance diagnostic.

  2. Beta/alpha continuous air monitor

    Science.gov (United States)

    Becker, G.K.; Martz, D.E.

    1988-06-27

    A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinquishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts. 7 figs.

  3. Cancer from internal emitters

    International Nuclear Information System (INIS)

    Boecker, B.B.; Griffith, W.C. Jr.

    1995-01-01

    Irradiation from internal emitters, or internally deposited radionuclides, is an important component of radiation exposures encountered in the workplace, home, or general environment. Long-term studies of human populations exposed to various internal emitters by different routes of exposure are producing critical information for the protection of workers and members of the general public. The purpose of this report is to examine recent developments and discuss their potential importance for understanding lifetime cancer risks from internal emitters. The major populations of persons being studied for lifetime health effects from internally deposited radionuclides are well known: Lung cancer in underground miners who inhaled Rn progeny, liver cancer from persons injected with the Th-containing radiographic contrast medium Thorotrast, bone cancer from occupational or medical intakes of 226 Ra or medical injections of 224 Ra, and thyroid cancer from exposures to iodine radionuclides in the environment or for medical purposes

  4. Old and new versions of the alpha radiation theory of petroleum origin

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    1981-03-01

    Some aspects of petroleum formation and the world distribution of fossil fuels deposits were recent clarified. However, the source of energy associated with petroleum genesis is still largely debatable. Evidence accumulated over the years allows to demonstrate the energetic feasibility of a modern version of the old alpha radiation theory of petroleum origin. This theory is reviewed and examined critically under new light to be reformulated by taking advantage of relevant interdisciplinary data mostly not available when the old alpha radiation theory was suggested, developed and then discredited. The geological ages accepted for the formation of most of the known petroleum reserves are within a range that makes long-lived natural alpha emitters a feasible energy source for at least part of the energy necessary for the formation of petroleum hydrocarbon. (author) [pt

  5. Effects of internally deposited alpha emitters

    International Nuclear Information System (INIS)

    Rundo, J.; Schlenker, R.A.; Stebbings, J.H.

    1985-01-01

    This study seeks to identify and quantify the human health effects of occupational exposures to radium, use the health effects data from the radium study to predict responses to other alpha-emitting and/or bone-seeking radionuclides at occupational exposure levels and above, and predict the effects of these radionuclides, specifically environmental radium and its daughters, at nonoccupational exposure levels. 14 refs

  6. Critical indices for reversible gamma-alpha phase transformation in metallic cerium

    Science.gov (United States)

    Soldatova, E. D.; Tkachenko, T. B.

    1980-08-01

    Critical indices for cerium have been determined within the framework of the pseudobinary solution theory along the phase equilibrium curve, the critical isotherm, and the critical isobar. The results obtained verify the validity of relationships proposed by Rushbrook (1963), Griffiths (1965), and Coopersmith (1968). It is concluded that reversible gamma-alpha transformation in metallic cerium is a critical-type transformation, and cerium has a critical point on the phase diagram similar to the critical point of the liquid-vapor system.

  7. Source preparations for alpha and beta measurements

    Energy Technology Data Exchange (ETDEWEB)

    Holm, E. [Risoe National Lab., Roskilde (Denmark)

    2001-01-01

    Regarding alpha particle emitters subject for environmental studies, electrodeposition or co-precipitation as fluorides are the most common methods. For electro deposition stainless steel is generally used as cathode material but also other metals such as Ni, Ag, and Cu showed promising results. The use of other anode material than platinum, such as graphite should be investigated. For other purposes such as optimal resolution other more sophisticated methods are used but often resulting in poorer recovery. For beta particle emitters the type of detection system will decide the source preparation. Similar methods as for alpha particle emitters, electrodeposition or precipitation techniques can be used. Due to the continuous energy distribution of the beta pulse height distribution a high resolution is not required. Thicker sources from the precipitates or a stable isotopic carrier can be accepted but correction for absorption in the source must be done. (au)

  8. Real-time monitoring for alpha emitters in high-airflow environments

    International Nuclear Information System (INIS)

    Koster, J.E.; MacArthur, D.W.; Bounds, J.A.; Rawool-Sullivan, M.; Whitley, C.R.; Conaway, J.G.; Steadman, P.A.

    1996-01-01

    Key problems in detecting alpha contamination for site characterization and decontamination and decommissioning that remain to be solved include measurement of airborne contamination, material holdup within pipes, and leakage of material containers. These problems are very difficult using traditional alpha detectors and systems. The ionization detection method (long-range alpha detection of LRAD) offers a number of specific advantages for these environmental measurements. An LRAD system detects the air molecules ionized by alpha-emitting contamination rather than the alpha particles. Thus, LRAD-based detectors are not limited by the short range of alpha particles and can be used to detect contamination anywhere that air can penetrate. Extending this technology to large enclosures of long pipes requires a system optimized for large airflows. In this paper we will present designs and preliminary results for high-volume flow-through air monitors based on the LRAD technique. In addition, we will discuss the behavior of the monitors and their potential applications

  9. Release of alpha emitters into the environment by Nuclear Industries of Brazil in Resende, RJ

    International Nuclear Information System (INIS)

    Pereira, Wagner S.; Kelecom, Alphonse; Santos, Rodney; Santos, Maisa F.M.; Torres, Vinicius R.M.; Rodrigues, Jéssica J.S.; Universidade Veiga de Almeida; Universidade Federal Fluminense

    2017-01-01

    The Nuclear Industries of Brazil operates in the field of nuclear energy and has a monopoly on mining and manufacturing the nuclear fuel element in Brazil. The Nuclear Fuel Factory is also responsible for the reconversion process, the manufacture of the pellets and the assembly of the fuel element. Once there is a possibility of particulate material generation during the reconversion processes and the manufacture of pellets, a method of collective protection of the worker was established, which includes a system of air exhaustion of the factory area, with the capacity to renew the indoor air six times per hour. As a control measure, there is a system of automatic detection of the release of radionuclides in the chimney that monitors and calculates the released values. Through the dose calculation model established by the National Commission for Nuclear Energy the release limit is fixed at 1.2∙ 10"7Bq.y"-"1 of alpha emitters by FCN. The present work aims to evaluate the alpha radionuclides released by FCN, in terms of total release (Bq) and Activity Concentration (AC, mBq∙m"-"3). In 2016 it was released 4.14∙10"6Bq.y"-"1, which means an average of 3.45∙10"5Bq.month"-"1. The largest mean for AC was 4.03 mBq∙m"-"3. The release data was almost an order of magnitude lower than the annual release limit, proving the suitability of the atmospheric effluents to the licensing requirements. The largest magnitudes of the two variables (AC and release) were observed in August while the smallest ones, in January. (author)

  10. Release of alpha emitters into the environment by Nuclear Industries of Brazil in Resende, RJ

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner S.; Kelecom, Alphonse; Santos, Rodney; Santos, Maisa F.M.; Torres, Vinicius R.M.; Rodrigues, Jéssica J.S., E-mail: comap@inb.gov.br, E-mail: pereiraws@gmail.com, E-mail: lararapls@hotmail.com [Indústrias Nucleares do Brasil (COMAP.N/FCN/INB), Resende RJ (Brazil). Fábrica de Combustível Nuclear. Coordenação de Meio Ambiente e Proteção Radiológica Ambiental; Universidade Veiga de Almeida (UVA), Rio de Janeiro, RJ (Brazil); Universidade Federal Fluminense (LARARA-PLS/UFF), Niterói, RJ (Brazil). Laboratório de Radiobiologia e Radiometria

    2017-07-01

    The Nuclear Industries of Brazil operates in the field of nuclear energy and has a monopoly on mining and manufacturing the nuclear fuel element in Brazil. The Nuclear Fuel Factory is also responsible for the reconversion process, the manufacture of the pellets and the assembly of the fuel element. Once there is a possibility of particulate material generation during the reconversion processes and the manufacture of pellets, a method of collective protection of the worker was established, which includes a system of air exhaustion of the factory area, with the capacity to renew the indoor air six times per hour. As a control measure, there is a system of automatic detection of the release of radionuclides in the chimney that monitors and calculates the released values. Through the dose calculation model established by the National Commission for Nuclear Energy the release limit is fixed at 1.2∙ 10{sup 7}Bq.y{sup -1} of alpha emitters by FCN. The present work aims to evaluate the alpha radionuclides released by FCN, in terms of total release (Bq) and Activity Concentration (AC, mBq∙m{sup -3}). In 2016 it was released 4.14∙10{sup 6}Bq.y{sup -1}, which means an average of 3.45∙10{sup 5}Bq.month{sup -1}. The largest mean for AC was 4.03 mBq∙m{sup -3}. The release data was almost an order of magnitude lower than the annual release limit, proving the suitability of the atmospheric effluents to the licensing requirements. The largest magnitudes of the two variables (AC and release) were observed in August while the smallest ones, in January. (author)

  11. Treatment of carcinoma in situ of the urinary bladder with an alpha-emitter immunoconjugate targeting the epidermal growth factor receptor: a pilot study.

    Science.gov (United States)

    Autenrieth, Michael E; Seidl, Christof; Bruchertseifer, Frank; Horn, Thomas; Kurtz, Florian; Feuerecker, Benedikt; D'Alessandria, Calogero; Pfob, Christian; Nekolla, Stephan; Apostolidis, Christos; Mirzadeh, Saed; Gschwend, Jürgen E; Schwaiger, Markus; Scheidhauer, Klemens; Morgenstern, Alfred

    2018-07-01

    Patients with carcinoma in situ (CIS) of the bladder refractory to bacillus Calmette-Guérin (BCG) treatment are usually treated with cystectomy. Therefore, new treatment options with preservation of the urinary bladder are needed. The objective of the study was to investigate the feasibility, safety and efficacy of a novel targeted alpha-emitter immunotherapy for CIS after BCG treatment failure. A pilot study was conducted in 12 patients (age range 64-86 years, ten men, two women) with biopsy-proven CIS of the bladder refractory to BCG treatment. The patients were treated intravesically with a single instillation (one patient was treated twice) of the alpha-emitter 213 Bi coupled to an anti-EGFR antibody (366-821 MBq). The primary aims of the study were to determine the feasibility of treatment with the 213 Bi-immunoconjugate and evaluation of adverse effects. Therapeutic efficacy was monitored by histological mapping of the urinary bladder 8 weeks after treatment and at different time points thereafter. The study proved that intravesical instillation of the 213 Bi-immunoconjugate targeting EGFR is feasible. No adverse effects were observed and all blood and urine parameters determined remained in their normal ranges. Therapeutic efficacy was considered satisfactory, in that three of the 12 patients showed no signs of CIS 44, 30 and 3 months after treatment. Intravesical instillation of 213 Bi-anti-EGFR monoclonal antibody was well tolerated and showed therapeutic efficacy. Repeated instillation and/or instillation of higher activities of the 213 Bi-immunoconjugate might lead to better therapeutic outcomes. A phase I clinical trial is planned.

  12. Localization of Narrowband Single Photon Emitters in Nanodiamonds.

    Science.gov (United States)

    Bray, Kerem; Sandstrom, Russell; Elbadawi, Christopher; Fischer, Martin; Schreck, Matthias; Shimoni, Olga; Lobo, Charlene; Toth, Milos; Aharonovich, Igor

    2016-03-23

    Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bioimaging. However, current understanding of the origin of these emitters is extremely limited. In this work, we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond and are directly relevant to fabrication of novel quantum optics devices and sensors.

  13. Evaluation of surface contamination due to alpha using large area contamination monitors

    International Nuclear Information System (INIS)

    Raghavayya, M.

    1998-01-01

    Radioactive contamination at work places is evaluated routinely using either the swipe sampling technique or a contamination monitor. Commercially available alpha probes used for the purpose are usually circular and have a face diameter of 50 or 100 mm. Square faced probes are also available. A thin aluminized mylar membrane of thickness 0.45 to 0.9 mg.cm -2 is used to screen the phosphor in the alpha probe to protect it from external light. The membrane cuts off more alphas from low energy emitters than from higher energy alpha emitters. Moreover the response of the detector for alphas originating at all points under the detector face is not uniform, especially when the large area alpha monitors are used. These factors can introduce errors as high as 40% into the measurements. This paper aims to quantify these errors and describe a procedure to overcome the limitations. (author)

  14. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  15. Emittance preservation

    Energy Technology Data Exchange (ETDEWEB)

    Kain, V; Arduini, G; Goddard, B; Holzer, B J; Jowett, J M; Meddahi, M; Mertens, T; Roncarolo, F; Schaumann, M; Versteegen, R; Wenninger, J [European Organization for Nuclear Research, Geneva (Switzerland)

    2012-07-01

    Emittance measurements during the LHC proton run 2011 indicated a blow-up of 20 % to 30 % from LHC injection to collisions. This presentation will show the emittance preservation throughout the different parts of the LHC cycle and discuss the current limitations on emittance determination. An overview of emittance preservation through the injector complex as function of bunch intensity will also be given. Possible sources for the observed blow-up and required tests in 2012 will be presented. Possible improvements of emittance diagnostics and analysis tools for 2012 will be shown.

  16. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Sand, J.; Hannuksela, V.; Toivonen, J.; Ihantola, S.; Peraejaervi, K.; Toivonen, H.

    2010-01-01

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  17. Field emission characteristics of a small number of carbon fiber emitters

    Directory of Open Access Journals (Sweden)

    Wilkin W. Tang

    2016-09-01

    Full Text Available This paper reports an experiment that studies the emission characteristics of small number of field emitters. The experiment consists of nine carbon fibers in a square configuration. Experimental results show that the emission characteristics depend strongly on the separation between each emitter, providing evidence of the electric field screening effects. Our results indicate that as the separation between the emitters decreases, the emission current for a given voltage also decreases. The authors compare the experimental results to four carbon fiber emitters in a linear and square configurations as well as to two carbon fiber emitters in a paired array. Voltage-current traces show that the turn-on voltage is always larger for the nine carbon fiber emitters as compared to the two and four emitters in linear configurations, and approximately identical to the four emitters in a square configuration. The observations and analysis reported here, based on Fowler-Nordheim field emission theory, suggest the electric field screening effect depends critically on the number of emitters, the separation between them, and their overall geometric configuration.

  18. Strong coupling of collection of emitters on hyperbolic meta-material

    Science.gov (United States)

    Biehs, Svend-Age; Xu, Chenran; Agarwal, Girish S.

    2018-04-01

    Recently, considerable effort has been devoted to the realization of a strong coupling regime of the radiation matter interaction in the context of an emitter at a meta surface. The strong interaction is well realized in cavity quantum electrodynamics, which also show that strong coupling is much easier to realize using a collection of emitters. Keeping this in mind, we study if emitters on a hyperbolic meta materials can yield a strong coupling regime. We show that strong coupling can be realized for densities of emitters exceeding a critical value. A way to detect strong coupling between emitters and hyperbolic metamaterials is to use the Kretschman-Raether configuration. The strong coupling appears as the splitting of the reflectivity dip. In the weak coupling regime, the dip position shifts. The shift and splitting can be used to sense active molecules at surfaces.

  19. The average number of alpha-particle hits to the cell nucleus required to eradicate a tumour cell population

    International Nuclear Information System (INIS)

    Roeske, John C; Stinchcomb, Thomas G

    2006-01-01

    Alpha-particle emitters are currently being considered for the treatment of micrometastatic disease. Based on in vitro studies, it has been speculated that only a few alpha-particle hits to the cell nucleus are considered lethal. However, such estimates do not consider the stochastic variations in the number of alpha-particle hits, energy deposited, or in the cell survival process itself. Using a tumour control probability (TCP) model for alpha-particle emitters, we derive an estimate of the average number of hits to the cell nucleus required to provide a high probability of eradicating a tumour cell population. In simulation studies, our results demonstrate that the average number of hits required to achieve a 90% TCP for 10 4 clonogenic cells ranges from 18 to 108. Those cells that have large cell nuclei, high radiosensitivities and alpha-particle emissions occurring primarily in the nuclei tended to require more hits. As the clinical implementation of alpha-particle emitters is considered, this type of analysis may be useful in interpreting clinical results and in designing treatment strategies to achieve a favourable therapeutic outcome. (note)

  20. The relative effectiveness of inhaled alpha- and beta-emitting radionuclides in producing lung cancer

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Muggenburg, B.A.; Guilmetter, R.A.; Griffith, W.C.; McClellan, R.O.

    1988-01-01

    Proper assessment of a long-term human health risks associated with inhaled radionuclides requires knowledge of dose to critical cells and tissues and relationships between dose and effect for different biological end points. Results from epidemiological studies of exposed human populations provided important information for such assessments. However, because the types of exposures are limited, these results need to be supplemented with more detailed information on dosimetry and biological effects available through studies in laboratory animals and in vitro systems. To provide health risk information for inhaled fission product and actinide aerosols, life-span studies are being conducted using beagle dogs and other species at the Lovelace Inhalation Toxicology Research Institute (ITRI). Results of two life-span studies in dogs involving inhalation of the beta emitter 91 Y in fused aluminosilicate particles or the alpha emitter 239 PuO 2 are reported here

  1. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  2. A critical study of emittance measurements of intense low-energy proton beams

    CERN Document Server

    Evans, Lyndon R

    1972-01-01

    The measurement of emittance in low energy proton beams suffers from two perturbing effects: 1) the neutralisation of the beam by backstreaming secondary electrons and 2) the space charge blowup of the beam sample between defining and analysing apparatus. An experimental study shows a significant change of the emittance orientation when bias is used to eliminate the secondary electrons. Biased and non-biased cases are also compared with computed dynamics including space charge. Criteria for the slit size and drift distance which make the space charge blow-up negligible are derived. In addition a transverse coherent oscillation of the proton beam, which was revealed the measurements, is discussed briefly. (11 refs).

  3. Liquid scintillation counting techniques for the determination of some alpha emitting actinides: a review

    International Nuclear Information System (INIS)

    Mirashi, N.N.; Chander, Keshav; Aggarwal, S.K.

    2000-12-01

    The present report is a review of the work on liquid scintillation counting techniques, for the determination of alpha emitting actinides like uranium, plutonium, americium etc; for the last three decades (1970-1999). It covers the progress that has taken place in conventional liquid scintillation counting employing various solvents, scintillators and extractants. There is gradual development in instrumentation from integral counting of alpha emitters to alpha liquid scintillation spectrometry to resolve and identify different alpha emitters. These advancements have led to Pulse Shape Analysis (PSA) and Photon Electron Rejecting Alpha Liquid Scintillation Spectrometry (PERALS) techniques for the determination of the alpha emitters in the presence of beta and gamma activity. These techniques allow the determination of actinides at very low levels which has increased their applications to almost all the fields of chemistry; be it biomedical, environmental, geological or process chemistry of nuclear fuels. The development of biphasic technique using various extractants to separate different elements and counting in presence of one another has been made possible. Inorganic scintillators have been recently developed which have the advantage of eliminating effects of quenching and presence of beta/gamma emitting actinides. This review will serve as a reference to those who want to carry out work in the field of determination of actinides using liquid scintillation counting techniques. (author)

  4. Measurement of the absolute activity of alpha or beta emitters by measuring product nuclei (daughter) activity increase or by studing its radioactive decay

    International Nuclear Information System (INIS)

    Campos, L.C. de.

    1981-01-01

    A new method for determining absolute activity of alpha or beta emitters by measuring daughter product radioactive decay is presented. The separation method of UX from hexahydrated uranyl nitrate UO 2 (NO 3 ) 2 6H 2 O based on its dissolution in ethyl ether is described and the accuracy of this method is shown. The factors which accuate on total efficiency of a Geiger Mueller detector for beta particles are determined. The possibility to determine the mass of precursor element by daughter nuclei activity is shown. The results are compared with the one obtained by direct measurement of the mass (or number of atoms) of precursor radioactive substance and with theoretical values calculated for isotopes in secular equilibrium. (Author) [pt

  5. Determination of total alpha activity index in samples of radioactive wastes

    International Nuclear Information System (INIS)

    Galicia C, F. J.

    2015-01-01

    This study aimed to develop a methodology of preparation and quantification of samples containing radionuclides beta and/or alpha emitters, to determine the rates of alpha and beta total activity of radioactive waste samples. For this, a device of planchettes preparer was designed, to assist the planchettes preparation in a controlled environment and free of corrosive vapors. Planchettes were prepared in three means: nitrate, carbonate and sulfate, to different mass thickness, natural uranium (alpha and beta emitter) and in case of Sr-90 (beta emitter pure) only in half nitrate; and these planchettes were quantified in an alpha/beta counter, in order to construct the self-absorption curves for alpha and beta particles. These curves are necessary to determine the rate of alpha-beta activity of any sample because they provide the self-absorption correction factor to be applied in calculating the index. Samples with U were prepared with the help of the device of planchettes preparer and subsequently were analyzed in the proportional counter Mpc-100 Pic brand. Samples with Sr-90 were prepared without the device to see if there was a different behavior with respect to obtaining mass thickness. Similarly they were calcined and carried out count in the Mpc-100. To perform the count, first the parameters of counter operating were determined: operating voltages for alpha and beta particles 630 and 1500 V respectively, a count routine was generated where the time and count type were adjusted, and counting efficiencies for alpha and beta particles, with the aid of calibration sources of 210 Po for alphas and 90 Sr for betas. According to the results, the counts per minute will decrease as increasing the mass thickness of the sample (self-absorption curve), adjusting this behavior to an exponential function in all cases studied. The minor self-absorption of alpha and beta particles in the case of U was obtained in sulfate medium. The self-absorption curves of Sr-90 follow the

  6. Dosimetry of natural and man-made alpha emitters in plankton

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Baptista, G.B.; Wrenn, M.E.; Eisenbrid, M.

    1980-11-01

    Comparison between the natural and man-made alpha radiation dose rates to plankton can be important for predicting the potential long-term effects on aquatic biota resulting from the routine or accidental radioactive releases from the nuclear fuel cycle. A contribution is made here towards the goal of comparing natural with man-made alpha radiation dose rates to plankton using the same method of calculation in both cases. (Author) [pt

  7. Review of measurement techniques for stack monitoring of long-lived alpha emitters

    International Nuclear Information System (INIS)

    Kordas, J.F.; Phelps, P.L.

    1978-01-01

    As a result of the promulgation of new guidelines by the Environmental Protection Agency (40 CFR 190) for releases of long-lived, alpha-emitting substances, the stack-monitoring requirements for measuring long-lived alpha particles may change in terms of both monitored isotopes and the detection levels. This paper briefly reviews stack-monitoring requirements for long-lived alpha-emitting particles. It also examines the currently deployed alpha-particulate, stack-monitoring systems and discusses prototype systems that may be applicable to stack monitoring

  8. Targeted alpha therapy: Applications and current status

    International Nuclear Information System (INIS)

    Bruchertseifer, Frank

    2017-01-01

    Full text: The field of targeted alpha therapy has been developed rapidly in the last decade. Besides 223 Ra, 211 At and 212 Pb/ 212 Bi the alpha emitters 225 Ac and 213 Bi are promising therapeutic radionuclides for application in targeted alpha therapy of cancer and infectious diseases. The presentation will give a short overview about the current clinical treatments with alpha emitting radionuclides and will place an emphasis on the most promising clinical testing of peptides and antibodies labelled with 225 Ac and 213 Bi for treatment of metastatic castration-resistant prostate cancer patients with glioma and glioblastoma multiform, PSMA-positive tumor phenotype and bladder carcinoma in situ. (author)

  9. Some applications of Photon/Electron-Rejecting Alpha Liquid Scintillation (PERALS) spectrometry to the assay of alpha emitters

    International Nuclear Information System (INIS)

    McDowell, W.J.; Case, G.N.

    1988-01-01

    The combination of certain solvent extraction separations and a special kind of liquid scintillation detector and electronics designed for alpha spectrometry allows some highly accurate, yet simple determinations of alpha-emitting nuclides. Counting efficiency is 99.68% with backgrounds of 99.95%. The Photon/Electron Rejecting Alpha Liquid Scintillation (PERALS) equipment is described and procedures for the separation and determination of uranium, thorium, plutonium, polonium, radium, and trivalent actinides are outlined. 25 refs., 10 figs., 1 tab

  10. Risk estimates for exposure to alpha emitters

    International Nuclear Information System (INIS)

    1982-07-01

    The primary scope of this report is to evaluate the risk of lung cancer from occupational exposure to short-lived daughters of radon and thoron. The Subcommittee on Risk Estimates considers that inhalation of radon and thoron daughters is the major radiation hazard from alpha radiation in uranium mining. The secondary scope of this report is the consideration of the applicability of the risk estimates derived from miners to the general public. The risk to members of the public from radium-226 in drinking water is also considered. Some research requirments are suggested

  11. Alpha-particle autoradiography by solid state track detectors to spatial distribution of radioactivity in alpha-counting source

    International Nuclear Information System (INIS)

    Ishigure, Nobuhito; Nakano, Takashi; Enomoto, Hiroko; Koizumi, Akira; Miyamoto, Katsuhiro

    1989-01-01

    A technique of autoradiography using solid state track detectors is described by which spatial distribution of radioactivity in an alpha-counting source can easily be visualized. As solid state track detectors, polymer of allyl diglycol carbonate was used. The advantage of the present technique was proved that alpha-emitters can be handled in the light place alone through the whole course of autoradiography, otherwise in the conventional autoradiography the alpha-emitters, which requires special carefulness from the point of radiation protection, must be handled in the dark place with difficulty. This technique was applied to rough examination of self-absorption of the plutonium source prepared by the following different methods; the source (A) was prepared by drying at room temperature, (B) by drying under an infrared lamp, (C) by drying in ammonia atmosphere after redissolving by the addition of a drop of distilled water which followed complete evaporation under an infrared lamp and (D) by drying under an infrared lamp after adding a drop of diluted neutral detergent. The difference in the spatial distributions of radioactivity could clearly be observed on the autoradiographs. For example, the source (C) showed the most diffuse distribution, which suggested that the self-absorption of this source was the smallest. The present autoradiographic observation was in accordance with the result of the alpha-spectrometry with a silicon surface-barrier detector. (author)

  12. Radiological control in a mine with a naturally occurring radioactive material: NORM: I assessment of activity concentration of alpha emitter with long half live in the air in a pilot plant

    International Nuclear Information System (INIS)

    Pereira, W.S.; Py Junior, D.A.; Silva, A.C.A.; Garcia Filho, O.

    2013-01-01

    The Ore Treatment Unit (OTU) supports a laboratory process responsible for the development of new chemical processes for uranium extraction from ore elements associated with uranium. In 2009, a pilot plant for extraction of uranium from a phosphate ore mine with uranium associated was implanted, which is a case of Naturally Occurring Radioactive Material (NORM) in a mine at Santa Quiteria, CE, Brazil. This pilot plant was supervised by the radiological protection service, aiming the Occupational Exposed Individual' safety (OEI). During the pilot plant operation the monitoring of radionuclides concentration in air was carried out. During the functioning of the pilot plant 63 high-vol air monitoring and posterior gross alpha counts were made in order to evaluate the alpha emitters. One sampling was made before the beginning of operations in order to evaluate the background which was estimated in 0.003 Bq m -3 . Monitoring results varied between 0.001 Bq m -3 and 0.162 Bq m -3 with the average equal to 0.041 Bq m -3 . 100 % of the results were below the derived limit for OEI which is equal to 0.360 Bq m -3 . Thirty results were below the derived limit for public exposure. By using this criterion the area must be classified as Supervised Area. In order to correctly classify the area, the internal exposure must also be measured. The small values of air concentration of long lived alpha emitters can be explained by the process of uranium extraction that is made by solvent in a wet way that creates few aerosol particles in air that can be monitored by this method. (author)

  13. Radiological control in a mine with a naturally occurring radioactive material: NORM: I assessment of activity concentration of alpha emitter with long half live in the air in a pilot plant

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, W.S.; Py Junior, D.A.; Silva, A.C.A.; Garcia Filho, O., E-mail: pereiraws@gmail.com [Industrias Nucleares do Brasil (INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerio. Grupo Multidisciplinar de Radioprotecao; Kelecom, A., E-mail: akelecom@id.uff.br [Universidade Federal Fluminense (LARARA-PLS/GETA/UFF), Niteroi, RJ (Brazil). Laboratorio de Radiobiologia e Radiometria Pedro Lopes dos Santos. Grupo de Estudos em Temas Ambientais; Pereira, J.R.S., E-mail: pereirarsj@gmail.com [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2013-07-01

    The Ore Treatment Unit (OTU) supports a laboratory process responsible for the development of new chemical processes for uranium extraction from ore elements associated with uranium. In 2009, a pilot plant for extraction of uranium from a phosphate ore mine with uranium associated was implanted, which is a case of Naturally Occurring Radioactive Material (NORM) in a mine at Santa Quiteria, CE, Brazil. This pilot plant was supervised by the radiological protection service, aiming the Occupational Exposed Individual' safety (OEI). During the pilot plant operation the monitoring of radionuclides concentration in air was carried out. During the functioning of the pilot plant 63 high-vol air monitoring and posterior gross alpha counts were made in order to evaluate the alpha emitters. One sampling was made before the beginning of operations in order to evaluate the background which was estimated in 0.003 Bq m{sup -3}. Monitoring results varied between 0.001 Bq m{sup -3} and 0.162 Bq m{sup -3} with the average equal to 0.041 Bq m{sup -3}. 100 % of the results were below the derived limit for OEI which is equal to 0.360 Bq m{sup -3}. Thirty results were below the derived limit for public exposure. By using this criterion the area must be classified as Supervised Area. In order to correctly classify the area, the internal exposure must also be measured. The small values of air concentration of long lived alpha emitters can be explained by the process of uranium extraction that is made by solvent in a wet way that creates few aerosol particles in air that can be monitored by this method. (author)

  14. Liquid scintillation alpha spectrometry techniques

    International Nuclear Information System (INIS)

    McKlveen, J.W.; McDowell, W.J.

    1984-01-01

    Accurate, quantitative determinations of alpha emitting nuclides by conventional plate counting methods are difficult, because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive alternative with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination, to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium and colonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds of the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications. (orig.)

  15. Design and Development of Emittance Measurement Device by Using the Pepper-pot Technique

    Science.gov (United States)

    Pakluea, S.; Rimjaem, S.

    2017-09-01

    Transverse emittance of a charged particle beam is one of the most important properties that reveals the quality of the beam. It is related to charge density, transvers size and angular displacement of the beam in transverse phase space. There are several techniques to measure the transverse emittance value. One of practical methods is the pepper-pot technique, which can measure both horizontal and vertical emittance value in a single measurement. This research concentrates on development of a pepper-pot device to measure the transverse emittance of electron beam produced from an accelerator injector system, which consists of a thermionic cathode RF electron gun and an alpha magnet, at the Plasma and Beam Physics Research Facility, Chiang Mai University. Simulation of beam dynamics was conducted with programs PARMELA, ELEGANT and self-developed codes using C and MATLAB. The geometry, dimensions and location of the pepper-pot as well as its corresponding screen station position were included in the simulation. The result from this study will be used to design and develop a practical pepper-pot experimental station.

  16. Microprecipitation of barium sulfate as a suitable source for measurements of 226Ra by alpha spectrometry

    International Nuclear Information System (INIS)

    Fernandez-Cata, Geyser; Isaac-Olive, Keila : E-mail. geyser@instec.cu

    2007-01-01

    One of the most hazardous radionuclides released into the environment is the uranium's daughter 226 Ra. This nuclide behaves similar to calcium, therefore is highly toxic for humans. One of the suitable methods for its determination is alpha spectrometry. This technique, however, has as main drawback the source preparation which should be infinitely thin and massless, of regular, known, and reproducible shape, smaller in area than the active area of the detector and new (no sputtering or recoil losses). Among the various ways of preparing an alpha source are the electrodeposition and microprecipitation. Radium electrodeposition is not suitable to carry out because of the high reduction potential of this element, therefore non aqueous media is required and the chemical yield is not good. Radium however can be precipitated with barium sulfate and our previous work has shown that the precipitation is selective to this element in the presence of other alpha emitters such as uranium and polonium but divalent cations are incorporated to it. At the same time, manganese dioxide also precipitates radium free of divalent cations but alpha emitters such as uranium are present as well. The objective of this work was to establish a chemical procedure for the determination of 226 Ra in natural water by alpha spectrometry. The general methodology includes a preconcentration using a non selective coprecipitation via manganese dioxide (where cations are not included but alpha emitters do). Once the manganese dioxide is filtrated, it is re-dissolved and a selective microprecipitation using barium sulphate is carried out (where the only alpha emitter is radium). Details of the procedure, separation methods, source quality and discussion of the results will be given in the paper. (Author)

  17. Monte Carlo simulation of age-dependent radiation dose from alpha- and beta-emitting radionuclides to critical trabecular bone and bone marrow targets

    Science.gov (United States)

    Dant, James T.; Richardson, Richard B.; Nie, Linda H.

    2013-05-01

    Alpha (α) particles and low-energy beta (β) particles present minimal risk for external exposure. While these particles can induce leukemia and bone cancer due to internal exposure, they can also be beneficial for targeted radiation therapies. In this paper, a trabecular bone model is presented to investigate the radiation dose from bone- and marrow-seeking α and β emitters to different critical compartments (targets) of trabecular bone for different age groups. Two main issues are addressed with Monte Carlo simulations. The first is the absorption fractions (AFs) from bone and marrow to critical targets within the bone for different age groups. The other issue is the application of 223Ra for the radiotherapy treatment of bone metastases. Both a static model and a simulated bone remodeling process are established for trabecular bone. The results show significantly lower AFs from radionuclide sources in the bone volume to the peripheral marrow and the haematopoietic marrow for adults than for newborns and children. The AFs from sources on the bone surface and in the bone marrow to peripheral marrow and haematopoietic marrow also varies for adults and children depending on the energy of the particles. Regarding the use of 223Ra as a radionuclide for the radiotherapy of bone metastases, the simulations show a significantly higher dose from 223Ra and its progeny in forming bone to the target compartment of bone metastases than that from two other more commonly used β-emitting radiopharmaceuticals, 153Sm and 89Sr. There is also a slightly lower dose from 223Ra in forming bone to haematopoietic marrow than that from 153Sm and 89Sr. These results indicate a higher therapy efficiency and lower marrow toxicity from 223Ra and its progeny. In conclusion, age-related changes in bone dimension and cellularity seem to significantly affect the internal dose from α and β emitters in the bone and marrow to critical targets, and 223Ra may be a more efficient

  18. A critical review of radiation effects on borosilicate glasses

    International Nuclear Information System (INIS)

    Lanza, F.; Manara, A.; Rutten, F. van

    1981-01-01

    Most of the experimental values have been obtained by loading the glass with alpha emitters like Cm 244 and Pu 238. The data existing in literature on stored energy, and density variation are presented and discussed. Attention is given to the variation of the leaching rate due to the radiation effect. Samples loaded with alpha emitters have given data up to 0.17 dpa and such bombarded with heavy ions show large effects due to dose rate effects. A study on defect formation has shown that under electrons irradiation, formation of bubbles is possible. (DG)

  19. Procedure for determination of alpha emitters in urine and dregs samples

    International Nuclear Information System (INIS)

    Serdeiro, Nelida H.

    2005-01-01

    The purpose of this work is to establish the procedure for the identification and quantification of emitting alpha radionuclides in urine and dregs samples. This procedure are applied to all laboratories of the countries of the Project ARCAL LXXVII that determinate alpha emitting radionuclides in biological samples for biological assessment [es

  20. Targeted alpha therapy: Applications and current status

    Energy Technology Data Exchange (ETDEWEB)

    Bruchertseifer, Frank, E-mail: frank.bruchertseifer@ec.europa.eu [European Commission, Joint Research Centre, Karlsruhe (Germany)

    2017-07-01

    Full text: The field of targeted alpha therapy has been developed rapidly in the last decade. Besides {sup 223}Ra, {sup 211}At and {sup 212}Pb/{sup 212}Bi the alpha emitters {sup 225}Ac and {sup 213}Bi are promising therapeutic radionuclides for application in targeted alpha therapy of cancer and infectious diseases. The presentation will give a short overview about the current clinical treatments with alpha emitting radionuclides and will place an emphasis on the most promising clinical testing of peptides and antibodies labelled with {sup 225}Ac and {sup 213}Bi for treatment of metastatic castration-resistant prostate cancer patients with glioma and glioblastoma multiform, PSMA-positive tumor phenotype and bladder carcinoma in situ. (author)

  1. Low-emittance Storage Rings

    CERN Document Server

    Wolski, Andrzej

    2014-01-01

    The effects of synchrotron radiation on particle motion in storage rings are discussed. In the absence of radiation, particle motion is symplectic, and the beam emittances are conserved. The inclusion of radiation effects in a classical approximation leads to emittance damping: expressions for the damping times are derived. Then, it is shown that quantum radiation effects lead to excitation of the beam emittances. General expressions for the equilibrium longitudinal and horizontal (natural) emittances are derived. The impact of lattice design on the natural emittance is discussed, with particular attention to the special cases of FODO-, achromat- and theoretical-minimum-emittance-style lattices. Finally, the effects of betatron coupling and vertical dispersion (generated by magnet alignment and lattice tuning errors) on the vertical emittance are considered.

  2. Effective liquid drop description for alpha decay of atomic nuclei

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Duarte, S.B.; Rodriguez, O.; Guzman, F.; Goncalves, M.; Garcia, F.

    1998-06-01

    Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author)

  3. Self-absorption and self-scattering in emitter source of alpha particles

    International Nuclear Information System (INIS)

    Terini, R.A.

    1990-01-01

    This paper describes preliminary results on spectrometric analysis and activity measurements of alpha-emitting sources prepared by evaporation on mylar. The measurements were made with a Si surface barrier detector. By the analysis of the angular distribuition of the alpha particles emitted, it was possible to observe that the width of the spectrum low energy tail increases with the emission angle θ, due to the energy degradation in the source material, which affects the measured particles energy. The source activity was also measured from detection solid angles of approx. 10 -1 and aprox. 10 -3 Sr, as a function of θ. The absolute activity of the alpha source was determined and a discussion is present on the ideal conditions necessary for such measurements. (author) [pt

  4. Rare Earth Garnet Selective Emitter

    Science.gov (United States)

    Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

    1994-01-01

    Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional

  5. Survival of alpha particle irradiated cells as a function of the shape and size of the sensitive volume (nucleus)

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Roeske, J.C.

    1995-01-01

    Microdosimetry is the study of the stochastic variation of energy deposited within sub-cellular targets. As such, the size and shape of the critical target (i.e. cell nucleus) are essential when considering microdosimetric quantities. In this work, a microdosimetric analysis examines the expected cell survival as a function of the size and shape of the cell nucleus under conditions of irradiation emitting alpha particles. The results indicate that, in general, cell survival is relatively insensitive to changes in the shape of the cell nucleus when the volume is held constant. However, cell survival is a strong function of the variation in the size of the target. These results are useful when analysing the results of cell survival experiments for alpha particle emitters. (Author)

  6. Development of methodology for detection of long lived alpha emitters in air based on simultaneous alpha and beta activity measurement

    International Nuclear Information System (INIS)

    Kaushik, Vivek; Rath, D.P.; Vinayagami, Bhakti; Ashokkumar, P.; Umashankar, C.; Gopalakrishnan, R.K.; Kulkarni, M.S.

    2018-01-01

    Interference of the radon and thoron progeny co-deposited on the filtration media is the long-standing problem related to prompt analyses in continuous air sampling or monitoring of any potential suspect radionuclides. The solutions to this problem have been quite diverse, and included, for example, simple gross-alpha counting, the use of beta-to-alpha ratios, and the use of alpha spectrum analyses. The techniques based on beta to alpha disintegration ratios make use of the naturally occurring alpha to beta disintegration ratios and departures therefrom. This ratio is found empirically to be relatively constant. With the help of the solution of differential equation, which govern the deposition of radionuclide on filter paper, one can easily estimate theoretically the behavior of the radon progeny alpha to beta disintegration (or count) rate ratio

  7. Alpha/beta pulse shape discrimination in plastic scintillation using commercial scintillation detectors

    International Nuclear Information System (INIS)

    Bagan, H.; Tarancon, A.; Rauret, G.; Garcia, J.F.

    2010-01-01

    Activity determination in different types of samples is a current need in many different fields. Simultaneously analysing alpha and beta emitters is now a routine option when using liquid scintillation (LS) and pulse shape discrimination. However, LS has an important drawback, the generation of mixed waste. Recently, several studies have shown the capability of plastic scintillation (PS) as an alternative to LS, but no research has been carried out to determine its capability for alpha/beta discrimination. The objective of this study was to evaluate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape analysis (PSA). The results obtained show that PS pulses had lower energy than LS pulses. As a consequence, a lower detection efficiency, a shift to lower energies and a better discrimination of beta and a worst discrimination of alpha disintegrations was observed for PS. Colour quenching also produced a decrease in the energy of the particles, as well as the effects described above. It is clear that in PS, the discrimination capability was correlated with the energy of the particles detected. Taking into account the discrimination capabilities of PS, a protocol for the measurement and the calculation of alpha and beta activities in mixtures using PS and commercial scintillation detectors has been proposed. The new protocol was applied to the quantification of spiked river water samples containing a pair of radionuclides ( 3 H- 241 Am or 90 Sr/ 90 Y- 241 Am) in different activity proportions. The relative errors in all determinations were lower than 7%. These results demonstrate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape and to quantify mixtures without generating mixed waste.

  8. Cell survival following alpha particle irradiation: critical sites and implications for carcinogenesis

    International Nuclear Information System (INIS)

    Lloyd, E.L.; Gemmell, M.A.; Henning, C.B.; Gemmell, D.S.; Zabransky, B.J.

    1976-01-01

    In experiments in which mammalian cells were irradiated with 5.6 MeV alpha particles from a Tandem Van de Graaff machine we have confirmed the finding of others that the mean lethal dose (D 0 ) is about 100 rad, but by measurements of the area of the cell nuclei as irradiated we found that this mean lethal dose corresponds not to 1, as expected, but to about 27 alpha particles per cell nucleus. (The exact number appears to change slightly with cell passage number.) This allows for the possibility that the direct action of alpha particles on the nucleus may be the important event in carcinogenesis, a theory which was previously difficult to accept if a single particle hitting the nucleus anywhere was considered to be lethal. Evidence is presented to implicate the nucleolus as a possible critical site for the inhibition of reproductive integrity of the cell

  9. Effect of alpha irradiation on UO{sub 2} surface reactivity in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DIEC/SESC/LMPA, Bagnols-sur-Ceze (France); Jorion, F. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DRCP/SE2A/LEMA, Bagnols-sur-Ceze (France); Corbel, C. [Commissariat a l' Energie Atomique (CEA), Saclay Research Center, DSM/DRECAM/SCM, Gif sur Yvette (France)

    2005-07-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO{sub 2} matrix in aqueous media subjected to {alpha}-{beta}-{gamma} radiation. The {beta}-{gamma} emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO{sub 2} pellets doped with alpha emitters ({sup 238}Pu and {sup 239}Pu) to quantify the impact of alpha irradiation on UO{sub 2} matrix alteration. Three batches of doped UO{sub 2} pellets with different alpha flux levels (3.30 x 10{sup 4}, 3.30 x 10{sup 5}, and 3.2 x 10{sup 6} {alpha} cm{sup -2} s{sup -1}) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO{sub 2} matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO{sub 2} pellets doped with alpha emitters results in variations of the UO{sub 2} surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO{sub 2} pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO{sub 2} to UO{sub 2+x}. However, leaching experiments performed in deaerated media after annealing the samples and

  10. Incineration of technological waste contaminated with alpha emitters

    International Nuclear Information System (INIS)

    Otter, C.; Moncouyoux, J.P.; Cartier, R.; Durec, J.P.; Afettouche, R.

    1990-01-01

    A large R and D programme is in progress at the CEA on alpha-bearing waste incineration. The program is developed in the laboratory and a pilot plant including the following aspects: physico-chemical characterization of wastes, study of thermal decomposition of wastes, laboratory study of generated gases (first with inactive then with active wastes), development of an industrial pilot plant with inactive wastes, study of corrosion resistance of material (laboratory and pilot plant), study and qualification of nuclear measurements on wastes, ashes and equipment [fr

  11. Effect of alpha irradiation on UO2 surface reactivity in aqueous media

    International Nuclear Information System (INIS)

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D.; Jorion, F.; Corbel, C.

    2005-01-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO 2 matrix in aqueous media subjected to α-β-γ radiation. The β-γ emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO 2 pellets doped with alpha emitters ( 238 Pu and 239 Pu) to quantify the impact of alpha irradiation on UO 2 matrix alteration. Three batches of doped UO 2 pellets with different alpha flux levels (3.30 x 10 4 , 3.30 x 10 5 , and 3.2 x 10 6 α cm -2 s -1 ) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO 2 matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO 2 pellets doped with alpha emitters results in variations of the UO 2 surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO 2 pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO 2 to UO 2+x . However, leaching experiments performed in deaerated media after annealing the samples and preleaching the surface suggest that alpha radiolysis does indeed affect the dissolution, which varies with the

  12. Alpha particle analysis using PEARLS spectrometry

    International Nuclear Information System (INIS)

    McKlveen, J.W.; Klingler, G.W.; McDowell, W.J.; Case, G.N.

    1984-01-01

    Alpha particle assay by conventional plate-counting methods is difficult because chemical separation, tracer techniques, and/or self-absorption losses in the final sample may cause either non-reproducible results or create unacceptable errors. PEARLS (Photon-Electron Rejecting Alpha Liquid Scintillation) Spectrometry is an attractive alternative since radionuclides may be extracted into a scintillator in which there would be no self-absorption or geometry problems and in which up to 100% chemical recovery and counting efficiency is possible. Sample preparation may include extraction of the alpha emitter of interest by a specific organic-phase-soluble compound directly into the liquid scintillator. Detection electronics use energy and pulse-shape discrimination to provide discrete alpha spectra and virtual absence of beta and gamma backgrounds. Backgrounds on the order of 0.01 cpm are readily achievable. Accuracy and reproducibility are typically in the 100 +-1% range. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium, and polonium assay. This paper will review liquid scintillation alpha counting methods and reference some of the specific applications. 8 refs., 1 fig

  13. Effective liquid drop description for alpha decay of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, O.A.P.; Duarte, S.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencia y Tecnologia Nuclear (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1998-06-01

    Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author) 44 refs., 5 figs., 3 tabs.; e-mail: telo at ird.gov.br

  14. Alpha radioisotopes Ac-225 and Bi-213: a production and labelling of antibodies and peptides for clinical use

    Energy Technology Data Exchange (ETDEWEB)

    Bruchertseifer, Frank, E-mail: frank.bruchertseifer@ec.europa.eu [European Commission, Joint Research Centre, Karlsruhe (Germany)

    2017-07-01

    Full text: In various preclinical and clinical works the potential of the alpha emitters {sup 225}Ac and {sup 213}Bi as therapeutic radionuclides for application in targeted alpha therapy of cancer and infectious diseases was demonstrated. Both alpha emitters are available with high specific activity from established radionuclide generators. Their favorable chemical and physical properties have led to the conduction of a large number of preclinical studies and several clinical trials, demonstrating the feasibility, safety and therapeutic efficacy of targeted alpha therapy with {sup 225}Ac and {sup 213}Bi. This presentation will give an overview about the methods for the production of {sup 225}Ac and {sup 213}Bi, the {sup 225}Ac/{sup 213}Bi radionuclide generator systems, labelling of peptides and antibodies with {sup 225}Ac and {sup 213}Bi and relevant in vivo and in vitro works. (author)

  15. A review of the alpha-1 foundation: its formation, impact, and critical success factors.

    Science.gov (United States)

    Walsh, John W; Snider, Gordon L; Stoller, James K

    2006-05-01

    Patient-advocacy organizations have proliferated because they can be an effective method to advance research and clinical care for those with the index condition, and can produce substantial benefits for the affected community, especially when the condition is uncommon. To clarify critical success factors in organizing a patient-advocacy organization and to provide a blueprint for others, including the respiratory-care advocacy community, this report examines features of one highly successful organization, the Alpha-1 Foundation, which is committed to helping those with the genetic condition alpha-1 antitrypsin deficiency. Features of the Alpha-1 Foundation that underlie its success include: consistently creating partnerships with key stakeholders, including the scientific and clinical communities, government, and pharmaceutical manufacturers; bringing passion to the cause (eg, by assuring that organizational leadership is provided by individuals affected by alpha-1 antitrypsin deficiency); and developing strategic business partnerships, as with a company that administers alpha-1 antitrypsin treatment (so-called intravenous augmentation therapy) and employs individuals with alpha-1 antitrypsin deficiency. Funds allocated by the company help to underwrite the foundation's research-funding commitment. The foundation also recruits and retains talent, including alpha-1 patients, to leadership roles (eg, on the board of directors) and has a voluntary group of committed scientists and clinicians. We believe that attention to these factors can help assure the success of patient-advocacy groups.

  16. Shielding in ungated field emitter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J. R. [U.S. Navy Reserve, Navy Operational Support Center New Orleans, New Orleans, Louisiana 70143 (United States); Jensen, K. L. [Code 6854, Naval Research Laboratory, Washington, D.C. 20375 (United States); Shiffler, D. A. [Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, New Mexico 87117 (United States); Petillo, J. J. [Leidos, Billerica, Massachusetts 01821 (United States)

    2015-05-18

    Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can be used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 10{sup 2}–10{sup 4} are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays.

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

    International Nuclear Information System (INIS)

    Tobias, C.C.B.

    1982-01-01

    The absolute activity of U-235 contained in a UO 2 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) [pt

  18. Gross alpha radioactivity of drinking water in Venezuela

    International Nuclear Information System (INIS)

    Sajo-Bohus, L.; Gomez, J.; Greaves, E.D.; Herrera, O.; Salazar, V.; Smith, A.

    1997-01-01

    Bottled mineral water is consumed by a large population in Venezuela. The alpha emitters concentration was measured in samples of bottled water and water springs collected near the surface. Approximately 30% of the total mineral water suppliers was monitored. a database on natural and artificial radioactivity in drinking water was produced. Results indicate that 54% of the waters sampled contain a total alpha radioactivity of less than 0.185 Bql -1 and only 12% above 0.37 Bql -1 . Our results revealed a total annual dose of 2.3 mSv year -1 . (author)

  19. The WUW ML bundle detector A flow through detector for alpha-emitters

    CERN Document Server

    Wenzel, U; Lochny, M

    1999-01-01

    Using conventional laboratory ware, we designed and manufactured a flow through cell for monitoring alpha-bearing solutions. The cell consists of a bundle of thermoplastic, transparent tubes coated with a thin layer of the meltable scintillator MELTILEX sup T sup M at the inner surface. With appropriate energy windows set, the detector can suppress beta-particles to a great extent due to its geometrical dimensions. For pure alpha-solutions, the detection limits are 5 Bq/ml, for composite nuclide mixtures, the detector is capable to monitor the decontamination of medium active waste (<=10 sup 7 Bq/ml) down to 100 Bq alpha/g solution. At a throughput of 1 ml/s, the pressure build-up amounts to approx 2 bar. We have developed a quality control program to ensure the regularity of the individual bundle loops.

  20. Fission- and alpha-track study of biogeochemistry of plutonium and uranium in carbonates of Bikini and Enewetak atolls. Progress report, January 1, 1976--December 31, 1976

    International Nuclear Information System (INIS)

    Levy, Y.; Miller, D.S.; Friedman, G.M.

    1976-09-01

    Alpha emitters have been detected with a resolution of a few tens of micrometers using a solid state track detector (cellulose nitrate) to map the activity in a coral sample from Bikini. Calibration methods used include: a Pu source of 0.15 μCi in conjunction with polycarbonate and CaCO 3 absorbers of different thicknesses (2 to 30 micrometers), and a powdered coral sample which had been analyzed previously for alpha emitters by chemical methods in conjunction with an alpha spectrometer. 0.04 mm 3 can be measured routinely; smaller concentrations can be determined but with a lower resolution. CaCO 3 of the coral Favites virens from Bikini lagoon was analyzed by placing the detector directly on the sample for thirty days. Sections and thin sections cut perpendicular to one another, but parallel to the direction of coral growth, give very different concentrations and distributions of alpha emitters. Maximum concentrations of 800 pCi/g were measured in a volume of 0.004 mm 3 in void-filling cement separated from the coral and in an area in which coral skeleton and cement could not be distinguished. Areas of high alpha emitter concentrations coincide with areas of coral growth interruption where non coral material exists that is composed of a mixture of encrusting bryozoan like carbonate material and skeletal debris

  1. Micro-precipitation of Americium by Cerium Hydroxide for alpha spectrometry

    International Nuclear Information System (INIS)

    Wankhede, Sonal M.; Kumar, Suja A.; Sawant, Pramilla D.

    2018-01-01

    Estimation of trace amount of actinides in any biological and/or environmental sample is done by radiochemical separation followed by alpha spectrometry. Alpha-spectrometric determination of actinides requires thin, homogeneous and nearly weightless sample sources. The most widely used method for preparation of actinides for alpha spectrometry involves electro deposition of the alpha emitters using stainless steel planchetts (cathode) and platinum rod (anode). This procedure is time consuming, requires relatively elaborate equipment, and is expensive. Micro-precipitation technique using hydrofluoric acid (HF) is also reliable and already standardized at Bioassay Laboratory (Wankhede, 2016). However, it uses hazardous chemical such as HF, hence, in the present study, cerium hydroxide micro-precipitation technique was standardized

  2. Auger electron emitters: Insights gained from in vitro experiments

    International Nuclear Information System (INIS)

    Makrigiorgos, G.; Adelstein, S.J.; Kassis, A.I.

    1990-01-01

    This paper outlines the evolution of the current rationale for research into the biological effects of tissue-incorporated Auger electron emitters. The first section is a brief review of the research conducted by several groups in the last fifteen years. The second section describes the in vitro model used in our studies, dosimetric calculations, experimental techniques and recent findings. The third section focuses on the use of Auger electron emitters as in vitro microprobes for the investigation of the radiosensitivity of distinct subcellular components. Examination of the biological effects of the Auger electron emitter 125 I located in different cellular compartments of a single cell line (V 79 hamster lung fibroblast) verifies that DNA is the critical cell structure for radiation damage and that the sensitive sites are of nanometer dimensions. The data from incorporation of several Auger electron emitters at the same location within DNA suggest that there are no saturation effects from the decay of these isotopes (i.e. all the emitted energy is biologically effective) and provide some insight into which of the numerous physical mechanisms accompanying the Auger decay are most important in causing cell damage. Finally the implications of Auger electron emission for radiotherapy and radiation protection in diagnostic nuclear medicine are detailed and further research possibilities are suggested. (orig.)

  3. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing [Daly City, CA; Yang, Peidong [Kensington, CA; Kim, Woong [Seoul, KR; Fan, Rong [Pasadena, CA

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  4. Effect of metallic iron on the oxidative dissolution of UO2 doped with a radioactive alpha emitter in synthetic Callovian-Oxfordian groundwater

    Science.gov (United States)

    Odorowski, Mélina; Jegou, Christophe; De Windt, Laurent; Broudic, Véronique; Jouan, Gauthier; Peuget, Sylvain; Martin, Christelle

    2017-12-01

    In the hypothesis of direct disposal of spent fuel in a geological nuclear waste repository, interactions between the fuel mainly composed of UO2 and its environment must be understood. The dissolution rate of the UO2 matrix, which depends on the redox conditions on the fuel surface, will have a major impact on the release of radionuclides into the environment. The reducing conditions expected for a geological disposal situation would appear to be favorable as regards the solubility and stability of the UO2 matrix, but may be disturbed on the surface of irradiated fuel. In particular, the local redox conditions will result from a competition between the radiolysis effects of water under alpha irradiation (simultaneously producing oxidizing species like H2O2, hydrogen peroxide, and reducing species like H2, hydrogen) and those of redox active species from the environment. In particular, Fe2+, a strongly reducing aqueous species coming from the corrosion of the iron canister or from the host rock, could influence the dissolution of the fuel matrix. The effect of iron on the oxidative dissolution of UO2 was thus investigated under the conditions of the French disposal site, a Callovian-Oxfordian clay formation chosen by the French National Radioactive Waste Management Agency (Andra), here tested under alpha irradiation. For this study, UO2 fuel pellets doped with a radioactive alpha emitter (238/239Pu) were leached in synthetic Callovian-Oxfordian groundwater (representative of the French waste disposal site groundwater) in the presence of a metallic iron foil to simulate the steel canister. The pellets had varying levels of alpha activity, in order to modulate the concentrations of species produced by water radiolysis on the surface and to simulate the activity of aged spent fuel after 50 and 10,000 years of alpha radioactivity decay. The experimental data showed that whatever the sample alpha radioactivity, the presence of iron inhibits the oxidizing dissolution of

  5. Investigating proton emitters at the limits of stability with radioactive beams from the Oak Ridge facility

    Energy Technology Data Exchange (ETDEWEB)

    Toth, K.S. [Oak Ridge National Lab., TN (United States); Batchelder, J.C.; Zganjar, E.F. [Louisiana State Univ., Baton Rouge, LA (United States); Bingham, C.R.; Wauters, J. [Tennessee Univ., Knoxville, TN (United States); Davinson, T.; MacKenzie, J.A.; Woods, P.J. [Edinburgh Univ. (United Kingdom)

    1996-10-01

    By using beams from the Holifield Radioactive Ion Beam Facility at ORNL, it should be possible to identify many new ground-state proton emitters in the mass region from Sn to Pb. In these investigations nuclei produced in fusion-evaporation reactions will be separated from incident ions and dispersed in mass/charge with a recoil mass separator and then implanted into a double-sided Si strip detector for study of proton (and {alpha}-particle) radioactivity. This paper summarizes data presently extant on proton emitters and then focuses on tests and initial experiments that will be carried out with stable beams and with radioactive ions as they are developed at the Oak Ridge facility.

  6. FACET Emittance Growth

    Energy Technology Data Exchange (ETDEWEB)

    Frederico, J; Hogan, M.J.; Nosochkov, Y.; Litos, M.D.; Raubenheimer, T.; /SLAC

    2011-04-05

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to {approx}20 {micro}m long and {approx}10 {micro}m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.

  7. FACET Emittance Growth

    International Nuclear Information System (INIS)

    Frederico, Joel

    2011-01-01

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The FACET beamline consists of a chicane and final focus system to compress the 23 GeV, 3.2 nC electron bunches to ∼20 (micro)m long and ∼10 (micro)m wide. Simulations of the FACET beamline indicate the short-duration and large, 1.5% rms energy spread beams may suffer a factor of four emittance growth from a combination of chromaticity, incoherent synchrotron radiation (ISR), and coherent synchrotron radiation (CSR). Emittance growth is directly correlated to head erosion in plasma wakefield acceleration and is a limiting factor in single stage performance. Studies of the geometric, CSR, and ISR components are presented. Numerical calculation of the rms emittance can be overwhelmed by long tails in the simulated phase space distributions; more useful definitions of emittance are given. A complete simulation of the beamline is presented as well, which agrees with design specifications.

  8. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  9. Derived ERLs for inhalation of alpha-emitting aerorols

    International Nuclear Information System (INIS)

    Macdonald, H.F.

    1977-01-01

    Derived alpha action levels are expressed as dpm/m 3 and give the airborne concentration of an assumed mixture of α-emitters which if inhaled for a period of 4 hours would result in a dose commitment to members of the critical group in the exposed population equal to the emergency reference levels (ERLs) of dose recommended by the Medical Research Council (1975). The period of 4 hours is chosen as a realistic time during which an assessment of the severity of a release may be made and appropriate countermeasures instituted. The derived α ERLs are set with reference to the potential range of isotopic releases for a specific reactor system and in the case of gas-cooled magnox reactors, a value of 10 3 dpm/m 3 (170 Bqm -3 ) has been used. This level was based upon the lung and GI tract models originally recommended by ICRP 2 (1959:1964) and revised ERLs for the inhalation of α-emitters consequent upon the improved metabolic models subsequently proposed by the ICRP (1966:1972) are evaluated. It is shown that the derived α ERLs for irradiated magnox and AGR fuels are largely independent of the physico-chemical forms of the released material, while variations with cooling time of fuel are also discussed. In addition, the special limits imposed by the chemical toxicity of uranium when inhaled in a soluble, low enriched form are briefly outlined

  10. Low emittance photoinjectors

    International Nuclear Information System (INIS)

    Ferrario, Massimo

    2001-01-01

    Photon colliders require high charge polarized electron beams with very low normalized emittances, possibly lower than the actual damping rings design goals. Recent analytical and numerical efforts in understanding beam dynamics in RF photoinjectors have raised again the question as to whether the performances of an RF electron gun based injector could be competitive with respect to a damping ring. As a matter of discussion we report in this paper the most recent results concerning low emittance photoinjector designs: the production of polarized electron beams by DC and/or RF guns is illustrated together with space charge compensation techniques and thermal emittance effects. New ideas concerning multi-gun injection system and generation of flat beams by RF gun are also discussed

  11. Electrically-driven GHz range ultrafast graphene light emitter (Conference Presentation)

    Science.gov (United States)

    Kim, Youngduck; Gao, Yuanda; Shiue, Ren-Jye; Wang, Lei; Aslan, Ozgur Burak; Kim, Hyungsik; Nemilentsau, Andrei M.; Low, Tony; Taniguchi, Takashi; Watanabe, Kenji; Bae, Myung-Ho; Heinz, Tony F.; Englund, Dirk R.; Hone, James

    2017-02-01

    Ultrafast electrically driven light emitter is a critical component in the development of the high bandwidth free-space and on-chip optical communications. Traditional semiconductor based light sources for integration to photonic platform have therefore been heavily studied over the past decades. However, there are still challenges such as absence of monolithic on-chip light sources with high bandwidth density, large-scale integration, low-cost, small foot print, and complementary metal-oxide-semiconductor (CMOS) technology compatibility. Here, we demonstrate the first electrically driven ultrafast graphene light emitter that operate up to 10 GHz bandwidth and broadband range (400 1600 nm), which are possible due to the strong coupling of charge carriers in graphene and surface optical phonons in hBN allow the ultrafast energy and heat transfer. In addition, incorporation of atomically thin hexagonal boron nitride (hBN) encapsulation layers enable the stable and practical high performance even under the ambient condition. Therefore, electrically driven ultrafast graphene light emitters paves the way towards the realization of ultrahigh bandwidth density photonic integrated circuits and efficient optical communications networks.

  12. New advanced in alpha spectrometry by liquid scintillation methods

    International Nuclear Information System (INIS)

    McDowell, W.J.; Case, G.N.

    1979-01-01

    Although the ability to count alpha particles by liquid scintillation methods has been long recognized, limited use has been made of the method because of problems of high background and alpha energy identification. In recent years some new developments in methods of introducing the alpha-emitting nuclide to the scintillator, in detector construction, and in electronics for processing the energy analog and time analog signals from the detector have allowed significant alleviation of the problems of alpha spectrometry by liquid scintillation. Energy resolutions of 200 to 300 keV full peak width at half maximum and background counts of 99% of all beta plus gamma interference is now possible. Alpha liquid scintillation spectrometry is now suitable for a wide range of applications, from the accurate quantitative determination of relatively large amounts of known nuclides in laboratory-generated samples to the detection and identification of very small, subpicocurie amounts of alpha emitters in environmental-type samples. Suitable nuclide separation procedures, sample preparation methods, and instrument configurations are available for a variety of analyses

  13. Alpha-beta-gamma spectrometer as an aid in directing decontamination of soils

    International Nuclear Information System (INIS)

    Berger, C.D.

    1981-01-01

    This technique permits rapid assessment of alpha-beta-gamma-emitter contamination in soils at sufficiently low concentrations to direct field operations. Of particular importance is its applicability during initial decommissioning and decontamination surveys when characterization of alpha and beta contamination in the presence of a high gamma background is necessary. This system has not yet been made portable for in-situ use, but it is expected that results willbe favorable when operated as a field instrument, resulting in simplified standard decontamination operation

  14. High brightness fiber laser pump sources based on single emitters and multiple single emitters

    Science.gov (United States)

    Scheller, Torsten; Wagner, Lars; Wolf, Jürgen; Bonati, Guido; Dörfel, Falk; Gabler, Thomas

    2008-02-01

    Driven by the potential of the fiber laser market, the development of high brightness pump sources has been pushed during the last years. The main approaches to reach the targets of this market had been the direct coupling of single emitters (SE) on the one hand and the beam shaping of bars and stacks on the other hand, which often causes higher cost per watt. Meanwhile the power of single emitters with 100μm emitter size for direct coupling increased dramatically, which also pushed a new generation of wide stripe emitters or multi emitters (ME) of up to 1000μm emitter size respectively "minibars" with apertures of 3 to 5mm. The advantage of this emitter type compared to traditional bars is it's scalability to power levels of 40W to 60W combined with a small aperture which gives advantages when coupling into a fiber. We show concepts using this multiple single emitters for fiber coupled systems of 25W up to 40W out of a 100μm fiber NA 0.22 with a reasonable optical efficiency. Taking into account a further efficiency optimization and an increase in power of these devices in the near future, the EUR/W ratio pushed by the fiber laser manufacturer will further decrease. Results will be shown as well for higher power pump sources. Additional state of the art tapered fiber bundles for photonic crystal fibers are used to combine 7 (19) pump sources to output powers of 100W (370W) out of a 130μm (250μm) fiber NA 0.6 with nominal 20W per port. Improving those TFB's in the near future and utilizing 40W per pump leg, an output power of even 750W out of 250μm fiber NA 0.6 will be possible. Combined Counter- and Co-Propagated pumping of the fiber will then lead to the first 1kW fiber laser oscillator.

  15. Low emittance electron storage rings

    Science.gov (United States)

    Levichev, E. B.

    2018-01-01

    Low-emittance electron (positron) beams are essential for synchrotron light sources, linear collider damping rings, and circular Crab Waist colliders. In this review, the principles and methods of emittance minimization are discussed, prospects for developing relativistic electron storage rings with small beam phase volume are assessed, and problems related to emittance minimization are examined together with their possible solutions. The special features and engineering implementation aspects of various facilities are briefly reviewed.

  16. Sources of series resistance in the Harwell solid state alpha detector

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1985-12-01

    The metal-semiconductor contacts to the Harwell solid state alpha detector have been characterized and the effect of the contact geometry has been assessed. To a reasonable approximation the latter gives rise to an emitter series resistance with an expected range of 20 +- 8 ohms. The contacts behave like parallel RC networks which become noticeably frequency dependent above ca. 100 kHz. Up to this frequency the emitter contact is likely to add 6 +- 4 ohms to the series resistance and the contribution from the base contact varies inversely with the square of the diode's diameter, being 5 +- 3 ohms for a diode with a diameter of 30 mm. (author)

  17. Selection of emitter material for application on a radioisotope thermophotovoltaic (RTPV) power system

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, D.P.; Frohlich, N.D.; Koehler, F.A.; Ruhkamp, J.D.; Miller, R.G.; McDougal, J.R.; Pugh, B.K.; Barklay, C.D.; Howell, E.I. [EGG Mound Applied Technologies Building 88, P.O. Box 3000 Miamisburg, Ohio45343 (United States)

    1997-01-01

    Radioisotope Thermophotovoltaic (RTPV) power systems are being considered for long duration space missions due to their predicted high thermal to electrical conversion efficiencies. One critical aspect of these power systems is the selection of an appropriate emitter material which will efficiently radiate the thermal energy generated by the heat source to the photovoltaics. The photovoltaics are {open_quotes}tuned{close_quotes} to convert the infrared wavelengths radiated by the emitter into electrical energy. The emphasis of this paper is on the selection and optimization of an appropriate emitter material which would meet all of the mission requirements. A Kepner Tregoe analysis was performed in order to rank the various candidate refractory materials in relationship to their physical and chemical properties. The results of the analysis and material recommendations are discussed. {copyright} {ital 1997 American Institute of Physics.}

  18. Dielectric optical antenna thermal emitters and metamaterials

    Science.gov (United States)

    Schuller, Jonathan Aaron

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this thesis, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial. We further show that these particles can serve as "broadcasting" antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas.

  19. Investigation of alpha emitters in fresh and powdered blood of fertile women: an in vitro application of CR-39 NTDs

    International Nuclear Information System (INIS)

    Salih, N.F.; University of Koya, Kurdistan; Jaafar, M.S.

    2014-01-01

    Blood samples were acquired from 60 women aged 20-44 years having decreased fertility, infertile or with uterine tumors in the Iraqi Kurdistan region. The concentrations of α emitters in fresh blood ranged from 0.0029 to 0.0088 ppm, whereas those in powdered blood ranged from 0.0036 ppm in Eiskan to 0.0096 ppm in Halabjay-Kon in Sulaymania. The α emitter concentrations in fresh blood ranged from 0.0029 to 0.0139 ppm, whereas those in powdered blood ranged from 0.0031 ppm in Shorsh to 0.0146 ppm in Sedakan in the Erbil Governorate. However, the concentrations of α emitters in the blood of women with decreased fertility were higher in the North than women from South Iraq. The difference significantly p < 0.001 revealed higher means of track density of fresh and powder blood in Erbil compared to Sulaymania. α are more damaging to the living tissue and exposure of the gonads leads to decreased fertility in women, most of data have been significant therefore, the result shown the radiation effect on women fertility. (author)

  20. Determination of Uranium plus Plutonium by Alpha spectrometry in different matrix

    International Nuclear Information System (INIS)

    Equillor, Hugo E.; Campos, Juan M.

    2011-01-01

    Usually, the determination of alpha emitters by alpha spectrometry is performed with a prior purification of each of the elements to be quantified. In this work, a methodology for the determination of uranium and plutonium isotopes as jointly described, in order to improve analytical processing times and measurement. The method includes purifying uranium and plutonium, and the subsequent electrodeposition for alpha spectrometry measurement. The technique is based on the use of TBP (tributyl phosphate) as extractant and easy to obtain reactants. It is applicable to various matrices, including water, filters and soils. In the conditions described, is applied to small aliquots of approximately 0.5 g of solid. The technique produces high quality electrodeposits. (authors) [es

  1. Reduced widths of alpha -decay of near-magic even-even nuclei

    CERN Document Server

    Kar Yan, N

    1972-01-01

    Precision on-line investigations on the linear heavy-ion Berkeley accelerator, and on the CERN synchrophasotron were carried out recently on new alpha -emitters. The results obtained are analysed with a view to finding the degree of correspondence, or disagreement, with the authors' own ideas about alpha -decay processes. The discussion is confined to examining even isotopes of polonium, radon, radium and thorium Several theoretical and experimental plots are given of reduced widths of alpha -disintegration for different regions of shell filling and a comparison is made between barrier penetration coefficients, obtained by rigorous methods and with the aid of WKB- approximation, for /sup 212/Po, /sup 208/Po and /sup 212/Po isotopes. (24 refs).

  2. Modified theoretical minimum emittance lattice for an electron storage ring with extreme-low emittance

    Directory of Open Access Journals (Sweden)

    Yi Jiao

    2011-05-01

    Full Text Available In the continuing efforts to reduce the beam emittance of an electron storage ring composed of theoretical minimum emittance (TME lattice, down to a level of several tens of picometers, nonlinear dynamics grows to be a great challenge to the performance of the storage ring because of the strong sextupoles needed to compensate for its large global natural chomaticities coupled with its small average dispersion function. To help in dealing with the challenge of nonlinear optimization, we propose a novel variation of theoretical minimum emittance (TME lattice, named as “modified-TME” lattice, with minimal emittance about 3 times of the exact theoretical minimum, while with more compact layout, lower phase advance per cell, smaller natural chromaticities, and more relaxed optical functions than that in a TME cell, by using horizontally defocusing quadrupole closer to the dipole or simply combined-function dipole with horizontally defocusing gradient. We present approximate scaling formulas to describe the relationships of the design parameters in a modified-TME cell. The applications of modified-TME lattice in the PEP-X storage ring design are illustrated and the proposed lattice appears a good candidate for synchrotron radiation light source with extremely low emittance.

  3. Applications of alpha particles detectors made of nitrocellulose film

    International Nuclear Information System (INIS)

    Segovia, N.; Salinas, B.; Pineda, H.

    1978-01-01

    We describe the experiments realized in order to probe the response of the alpha particles detectors manufactured in our laboratory and their suitability to some important applications. The detection system is a nitrocellulose film which register the transit of the charged particles. The traces left by the particles during their transit are manifested through a controlled chemical attack and counted after that with a microscope. This monitor system was utilized in the following applications: 1) uranium prospection 2) alpha autoradiography 4) determination of air pollution by alpha emitters. The results which were obtained are satisfactory and in spite that in these first applications only qualitative measurements were made the method could be used for quantitative determinations when we will have a better knowledge of the effect of factors which are not under our control. (author)

  4. A device for electron gun emittance measurement

    International Nuclear Information System (INIS)

    Aune, B.; Corveller, P.; Jablonka, M.; Joly, J.M.

    1985-05-01

    In order to improve the final emittance of the beam delivered by the ALS electron linac a new gun is going to be installed. To measure its emittance and evaluate the contribution of different factors to emittance growth we have developed an emittance measurement device. We describe the experimental and mathematical procedure we have followed, and give some results of measurements

  5. Alpha particles induce expression of immunogenic markers on tumour cells

    International Nuclear Information System (INIS)

    Gorin, J.B.; Gouard, S.; Cherel, M.; Davodeau, F.; Gaschet, J.; Morgenstern, A.; Bruchertseifer, F.

    2013-01-01

    The full text of the publication follows. Radioimmunotherapy (RIT) is an approach aiming at targeting the radioelements to tumours, usually through the use of antibodies specific for tumour antigens. The radiations emitted by the radioelements then induce direct killing of the targeted cells as well as indirect killing through bystander effect. Interestingly, it has been shown that ionizing radiations, in some settings of external radiotherapy, can foster an immune response directed against tumour cells. Our research team is dedicated to the development of alpha RIT, i.e RIT using alpha particle emitters, we therefore decided to study the effects of such particles on tumour cells in regards to their immunogenicity. First, we studied the effects of bismuth 213, an alpha emitter, on cellular death and autophagy in six different tumour cell lines. Then, we measured the expression of 'danger' signals and MHC molecules at the cell surface to determine whether irradiation with 213 Bi could cause the tumour cells to be recognized by the immune system. Finally a co-culture of dendritic cells with irradiated tumour cells was performed to test whether it would induce dendritic cells to mature. No apoptosis was detected within 48 hours after irradiation in any cell line, however half of them exhibited signs of autophagy. No increase in membrane expression of 'danger' signals was observed after treatment with 213 Bi, but we showed an increase in expression of MHC class I and II for some cell lines. Moreover, the co-culture experiment indicated that the immunogenicity of a human adenocarcinoma cell line (LS 174T) was enhanced in vitro after irradiation with alpha rays. These preliminary data suggest that alpha particles could be of interest in raising an immune response associated to RIT. (authors)

  6. Dielectric Optical Antenna Emitters and Metamaterials

    Science.gov (United States)

    Schuller, Jon

    2009-03-01

    Optical antennas are critical components in nanophotonics research due to their unparalleled ability to concentrate electromagnetic energy into nanoscale volumes. Researchers typically construct such antennas from wavelength-size metallic structures. However, recent research has begun to exploit the scattering resonances of high-permittivity particles to realize all-dielectric optical antennas, emitters, and metamaterials. In this talk, we experimentally and theoretically characterize the resonant modes of subwavelength rod-shaped dielectric particles and demonstrate their use in negative index metamaterials and novel infrared light emitters. At mid-infrared frequencies, Silicon Carbide (SiC) is an ideal system for studying the behavior of dielectric optical antennas. At frequencies below the TO phonon resonance, SiC behaves like a dielectric with very large refractive index. Using infrared spectroscopy and analytical Mie calculations we show that individual rod-shaped SiC particles exhibit a multitude of resonant modes. Detailed investigations of these SiC optical antennas reveal a wealth of new physics and applications. We discuss the distinct electromagnetic field profile for each mode, and demonstrate that two of the dielectric-type Mie resonances can be combined in a particle array to form a negative index metamaterial [1]. We further show that these particles can serve as ``broadcasting'' antennas. Using a custom-built thermal emission microscope we collect emissivity spectra from single SiC particles at elevated temperatures, highlighting their use as subwavelength resonant light emitters. Finally, we derive and verify a variety of general analytical results applicable to all cylindrical dielectric antennas and discuss extensions of the demonstrated concepts to different materials systems and frequency regimes. [1] J.A. Schuller, et al., Phys. Rev. Lett. 99, 107401 (2007)

  7. Determination of total alpha activity index in samples of radioactive wastes; Determinacion del indice de actividad alfa total en muestras de desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Galicia C, F. J.

    2015-07-01

    This study aimed to develop a methodology of preparation and quantification of samples containing radionuclides beta and/or alpha emitters, to determine the rates of alpha and beta total activity of radioactive waste samples. For this, a device of planchettes preparer was designed, to assist the planchettes preparation in a controlled environment and free of corrosive vapors. Planchettes were prepared in three means: nitrate, carbonate and sulfate, to different mass thickness, natural uranium (alpha and beta emitter) and in case of Sr-90 (beta emitter pure) only in half nitrate; and these planchettes were quantified in an alpha/beta counter, in order to construct the self-absorption curves for alpha and beta particles. These curves are necessary to determine the rate of alpha-beta activity of any sample because they provide the self-absorption correction factor to be applied in calculating the index. Samples with U were prepared with the help of the device of planchettes preparer and subsequently were analyzed in the proportional counter Mpc-100 Pic brand. Samples with Sr-90 were prepared without the device to see if there was a different behavior with respect to obtaining mass thickness. Similarly they were calcined and carried out count in the Mpc-100. To perform the count, first the parameters of counter operating were determined: operating voltages for alpha and beta particles 630 and 1500 V respectively, a count routine was generated where the time and count type were adjusted, and counting efficiencies for alpha and beta particles, with the aid of calibration sources of {sup 210}Po for alphas and {sup 90}Sr for betas. According to the results, the counts per minute will decrease as increasing the mass thickness of the sample (self-absorption curve), adjusting this behavior to an exponential function in all cases studied. The minor self-absorption of alpha and beta particles in the case of U was obtained in sulfate medium. The self-absorption curves of Sr-90

  8. Preliminary results of the alpha particle registration intercomparison ALRIT

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1976-01-01

    In view of the widespread interest in alpha particle registration with solid state nuclear track detectors, an international intercomparison of such measurements has been arranged. Sixteen sets of fourteen detectors each were sent to GSF-Neuherberg, there irradiated carefully with different alpha particle fields, and then returned for evaluation. Fourteen irradiation runs were made for each set simulating seven different irradiation situations commonly encountered in practical applications. The preliminary results of this intercomparison reported in this paper are based on the results of eight sets. They show good agreement with respect to the determination of track densities in the case of vertical incident alpha particles. Also the results obtained for determination of particle energies and angle of incidence in most cases were rather accurate. However, apparently it is still rather difficult to determine accurately and precisely the specific activity of alpha emitters on a thick filter positioned at some distance, i.e. for the case of 2π-incidence and a broad energy spectrum. (orig.) [de

  9. Fabrication, characterization and simulation of 4H-SiC Schottky diode alpha particle detectors for pyroprocessing actinide monitoring

    Science.gov (United States)

    Garcia, Timothy Richard

    Pyroprocessing is a method of using high-temperature molten salts and electric fields to separate and collect fuel isotopes of used nuclear fuel. It has been has been tested in the U.S. at Idaho National Laboratory as a key step in closing the nuclear fuel cycle. One technical problem with the pyroprocessing method is a lack of knowledge regarding the actinide concentrations in the salt bath during operation, since on-line techniques for measuring these concentrations are not presently available. 4H-SiC Schottky diode detectors can potentially fulfill this need. Such detectors would operate in contact with the molten salt, and measure concentrations via alpha-particle spectroscopy. This work seeks to fabricate and characterize 4H-SiC Schottky diode detectors at high temperature, model the alpha particle spectrum expected in a molten salt, and model the operation of the detectors to confirm the physics of operation is as expected. In this work, 4H-SiC Schottky diode detectors were fabricated at OSU Nanotech West. After fabrication, these detectors were characterized using both I-V curves and Am-241 alpha-particle energy spectra. All measurements were made as a function of temperature, from room temperature up to 500°C. The average energy required to create an electron-hole pair was observed to decrease with an increase of temperature, due to a decrease of both the 4H-SiC bandgap and non-linear energy loss terms. Furthermore, the FWHM of the spectra was observed to be dependent on the leakage current at a certain temperature, and not dependent on the temperature itself. Secondly, the alpha particle energy spectrum in the pyroprocessing environment was modeled using SRIM. The molten salt was modeled in 3 different geometries, with or without a protective cover material on top of the detector. Due to the loss of alpha-particle energy in the molten salt itself, a high-energy alpha emitter may completely cover the spectrum from a lower-energy alpha emitter. Each of the

  10. Alpha decay calculations with a new formula

    International Nuclear Information System (INIS)

    Akrawy, D T; Poenaru, D N

    2017-01-01

    A new semi-empirical formula for calculations of α  decay half-lives is presented. It was derived from the Royer relationship by introducing new parameters which are fixed by fit to a set of experimental data. We are using three sets: set A with 130 e–e (even–even), 119 e–o (even–odd), 109 o–e, and 96 o–o, set B with 188 e–e, 147 e–o, 131 o–e and 114 o–o, and set C with 136 e–e, 84 e–o, 76 o–e and 48 o–o alpha emitters. A comparison of results obtained with the new formula (newF) and the following well known relationships: semiempirical relationship based on fission theory (semFIS), analytical superasymmetric fission (ASAF) model and universal formula (UNIV) made in terms of rms standard deviation. We also introduced a weighted mean value of this quantity, allowing us to compare the global properties of a given model. For set B the order of the four models is the following: semFIS, UNIV, newF and ASAF. Nevertheless for even–even alpha emitters, UNIV gives the second best result after semFIS, and for odd–even parents the second is newF. Despite its simplicity in comparison with semFIS, newF, presented in this article, behaves quite well, competing with the other well known relationships. (paper)

  11. Diamond-based single-photon emitters

    International Nuclear Information System (INIS)

    Aharonovich, I; Castelletto, S; Simpson, D A; Su, C-H; Greentree, A D; Prawer, S

    2011-01-01

    The exploitation of emerging quantum technologies requires efficient fabrication of key building blocks. Sources of single photons are extremely important across many applications as they can serve as vectors for quantum information-thereby allowing long-range (perhaps even global-scale) quantum states to be made and manipulated for tasks such as quantum communication or distributed quantum computation. At the single-emitter level, quantum sources also afford new possibilities in terms of nanoscopy and bio-marking. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, as they are a photostable solid-state source of single photons at room temperature. In this review, we discuss the state of the art of diamond-based single-photon emitters and highlight their fabrication methodologies. We present the experimental techniques used to characterize the quantum emitters and discuss their photophysical properties. We outline a number of applications including quantum key distribution, bio-marking and sub-diffraction imaging, where diamond-based single emitters are playing a crucial role. We conclude with a discussion of the main challenges and perspectives for employing diamond emitters in quantum information processing.

  12. Emittance compensation of CW DC-gun photoinjector

    International Nuclear Information System (INIS)

    Li Peng; Wu Dai; Xu Zhou; Li Ming; Yang Xingfan

    2011-01-01

    Emittance growth induced by space charge effect is very important, especially for CW DC-gun photoinjector. In this work, the linear space charge force and its effect on electron beam transverse emittance are studied, and the principle and properties of emittance compensation by solenoid are analyzed. The CAEP DC-gun photoinjector with a solenoid is also simulated by code Parmela. Simulated results indicate that the normalized transverse emittance of an 80 pC bunch at the 350 keV DC-gun ex-it is 5.14 mm · mrad. And after compensated by a solenoid, it becomes 1.27 mm · mrad. The emittance of beam is well compensated. (authors)

  13. A low-emittance lattice for SPEAR

    International Nuclear Information System (INIS)

    Safranek, J.; Wiedemann, H.

    1992-01-01

    The design and implementation of a low emittance lattice for the SPEAR storage ring including measurements of the performance of the lattice are presented (J. Safranek, Ph. D. thesis, Stanford University, 1991). The low emittance lattice is designed to optimize the performance of SPEAR as a synchrotron radiation source while keeping SPEAR hardware changes at a minimum. The horizontal emittance of the electron beam in the low emittance lattice is reduced by a factor of 4 from the previous lattice. This reduces the typical horizontal source size and divergence of the photon beams by a factor of 2 each and increases the photon beam brightness. At 3 GeV the horizontal emittance is 129 π nm rad, which makes the low emittance lattice the lowest emittance, runnning synchroton radiation source in the world in the 1.5 to 4.0 GeV energy range for the emittance scaled to 3 GeV. The measured vertical emittance was reduced to half that typically seen at SPEAR in the past. The brightness of the photon beams was further incrased by reducing β y at the insertion devices to 1.1 m and reducing the energy dispersion at the insertion devices by more than a factor of 2 on average. The horizontal despersion at the rf cavities was reduced by a factor of nearly 4 which gives much less problems with synchrobetatron resonances. The dynamic and physical apertures of the lattice are large, giving long beam lifetimes and easy injection of electrons. The measurements of the linear optics and intensity dependent phenomena gave resonable agreement with the design . The overall performance of the machine was very good. Injection rates of 10 to 20 mA/min and larger were achieved routinely, and 100 mA total current was stored. Repeated ramping of stored beam from the injection energy of 2.3 GeV to the running energy of 3.0 GeV was achieved with very little beam loss. This low emittance configuration is expected to be the operating configuration for SPEAR starting in January 1992. (orig.)

  14. Radiation emitter-detector package

    International Nuclear Information System (INIS)

    O'Brien, J.T.; Limm, A.C.; Nyul, P.; Tassia, V.S. Jr.

    1978-01-01

    Mounted on the metallic base of a radiation emitter-detector is a mounting block is a first projection, and a second projection. A radiation detector is on the first projection and a semiconductor electroluminescent device, i.e., a radiation emitter, is on the second projection such that the plane of the recombination region of the electroluminescent device is perpendicular to the radiation incident surface of the radiation detector. The electroluminescent device has a primary emission and a secondary emission in a direction different from the primary emission. A radiation emitter-detector package as described is ideally suited to those applications wherein the secondary radiation of the electroluminescent device is fed into a feedback circuit regulating the biasing current of the electroluminescent device

  15. Emittance investigation of RF photo-injector

    CERN Document Server

    Yang Mao Rong; Li Zheng; Li Ming; Xu Zhou

    2002-01-01

    A high-power laser beam illuminates a photocathode surface placed on an end wall of an RF cavity. The emitted electrons are accelerated immediately to a relativistic energy by the strong RF find in the cavity. But space charge effect induces beam emittance growth especially near the cathode where the electrons are still nonrelativistic. The author analyzes the factors which lead the transverse emittance growth and method how to resolve this problem. After introducing solenoidal focusing near the photocathode, the beam emittance growth is suppressed dramatically. The beam emittance is given also after compensation and simulation results. The measurements show these results are coincident

  16. Double Emittance Exchanger as a Bunch Compressor for the MaRIE XFEL electron beam line at 1GeV

    Energy Technology Data Exchange (ETDEWEB)

    Malyzhenkov, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Northern Illinois Univ., DeKalb, IL (United States); Yampolsky, Nikolai [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carlsten, Bruce Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-22

    We demonstrate an alternative realization of a bunch compressor (specifically the second bunch compressor for the MaRIE XFEL beamline, 1GeV electron energy) using a double emittance exchanger (EEX) and a telescope in the transverse phase space.We compare our results with a traditional bunch compressor realized via chicane, taking into account the nonlinear dynamics, Coherent Synchrotron Radiation (CSR) and Space Charge (SC) effects. In particular, we use the Elegant code for tracking particles through the beam line and analyze the eigen-emittances evolution to separate the influence of the CSR/SC effects from the nonlinear dynamics effects. We optimize the scheme parameters to reach a desirable compression factor and minimize the emittance growth. We observe dominant CSR-effects in our scheme resulting in critical emittance growth and introduce alternative version of an emittance exchanger with a reduced number of bending magnets to minimize the impact of CSR effects.

  17. Noninterceptive transverse emittance measurements using BPM for Chinese ADS R&D project

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhi-Jun, E-mail: wangzj@impcas.ac.cn [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Feng, Chi [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); He, Yuan, E-mail: hey@impcas.ac.cn [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Dou, Weiping [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); Tao, Yue; Chen, Wei-long [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Jia, Huan; Liu, Shu-hui; Wang, Wang-sheng; Zhang, Yong; Wu, Jian-qiang; Zhang, Sheng-hu; Zhang, X.L. [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 73000 (China)

    2016-04-21

    The noninterceptive four-dimensional transverse emittance measurements are essential for commissioning the high power continue-wave (CW) proton linacs as well as their operations. The conventional emittance measuring devices such as slits and wire scanners are not well suited under these conditions due to sure beam damages. Therefore, the method of using noninterceptive Beam Position Monitor (BPM) is developed and demonstrated on Injector Scheme II at the Chinese Accelerator Driven Sub-critical System (China-ADS) proofing facility inside Institute of Modern Physics (IMP) [1]. The results of measurements are in good agreements with wire scanners and slits at low duty-factor pulsed (LDFP) beam. In this paper, the detailed experiment designs, data analysis and result benchmarking are presented.

  18. Minimization of the emittance growth of multi-charge particle beams in the charge stripping section of RAON

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ji-Gwang [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Eun-San, E-mail: eskim1@knu.ac.kr [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Hye-Jin, E-mail: hjkim87@ibs.re.kr [Rare Isotope Science Project, Institute for Basic Science, Jeonmin-dong, Yuseong-gu, Daejeon (Korea, Republic of); Jeon, Dong-O [Rare Isotope Science Project, Institute for Basic Science, Jeonmin-dong, Yuseong-gu, Daejeon (Korea, Republic of)

    2014-12-11

    The charge stripping section of the Rare isotope Accelerator Of Newness (RAON), which is one of the critical components to achieve a high power of 400 kW with a short lianc, is a source of transverse emittance growth. The dominant effects are the angular straggling in the charge stripper required to increase the charge state of the beam and chromatic aberrations in the dispersive section required to separate the selected ion beam from the various ion beams produced in the stripper. Since the main source of transverse emittance growth in the stripper is the angular straggling, it can be compensated for by changing the angle of the phase ellipse. Therefore the emittance growth is minimized by optimizing the Twiss parameters at the stripper. The emittance growth in the charge selection section is also minimized by the correction of high-order aberrations using six sextupole magnets. In this paper, we present a method to minimize the transverse emittance growth in the stripper by changing the Twiss parameters and in the charge selection section by using sextupole magnets.

  19. Small horizontal emittance in the TESLA damping ring

    International Nuclear Information System (INIS)

    Decking, W.

    2001-01-01

    The present TESLA damping ring is designed for a normalized horizontal emittance of 8x10 -6 m. γ-γ collisions at the TESLA linear collider will benefit from a further decrease of the horizontal emittance. This paper reviews the processes which limit the horizontal emittance in the damping ring. Preliminary estimates on the smallest horizontal emittance for the present TESLA damping ring design as well as an ultimate limit of the emittance reachable with the TESLA damping ring concept will be given

  20. Beam diagnostics using an emittance measurement device

    International Nuclear Information System (INIS)

    Sarstedt, M.; Becker, R.; Klein, H.; Maaser, A.; Mueller, J.; Thomae, R.; Weber, M.

    1995-01-01

    For beam diagnostics aside from Faraday cups for current measurements and analysing magnets for the determination of beam composition and energy the most important tool is an emittance measurement device. With such a system the distribution of the beam particles in phase-space can be determined. This yields information not only on the position of the particles but also on their angle with respect to the beam axis. There are different kinds of emittance measurement devices using either circular holes or slits for separation of part of the beam. The second method (slit-slit measurement), though important for the determination of the rms-emittance, has the disadvantage of integrating over the y- and y'-coordinate (measurement in xx'-plane assumed). This leads to different emittance diagrams than point-point measurements, since in xx'-plane for each two corresponding points of rr'-plane there exists a connecting line. With regard to beam aberrations this makes xx'-emittances harder to interpret. In this paper the two kinds of emittance diagrams are discussed. Additionally the influence of the slit height on the xx'-emittance is considered. The analytical results are compared to experimental measurements in rr'-, rx'- and xx'-phase-space. (orig.)

  1. Nonintercepting emittance monitor

    International Nuclear Information System (INIS)

    Miller, R.H.; Clendenin, J.E.; James, M.B.; Sheppard, J.C.

    1983-08-01

    A nonintercepting emittance monitor is a helpful device for measuring and improving particle beams in accelerators and storage rings as it allows continuous monitoring of the beam's distribution in phase space, and perhaps closed loop computer control of the distributions. Stripline position monitors are being investigated for use as nonintercepting emittance monitors for a beam focused by a FODO array in the first 100 meters of our linear accelerator. The technique described here uses the signal from the four stripline probes of a single position monitor to measure the quadrupole mode of the wall current in the beam pipe. This current is a function of the quadrupole moment of the beam, sigma 2 /sub x/ - sigma 2 /sub y/. In general, six independent measurements of the quadrupole moment are necessary to determine the beam emittance. This technique is dependent on the characteristically large variations of sigma 2 /sub x/ - sigma 2 /sub y/ in a FODO array. It will not work in a focusing system where the beam is round at each focusing element

  2. Low emittance configuration for spear

    International Nuclear Information System (INIS)

    Blumberg, L.N.; Harris, J.; Stege, R.; Cerino, J.; Hettel, R.; Hofmann, A.; Liu, R.Z.; Wiedemann, H.; Winick, H.

    1985-01-01

    The quality of synchrotron radiation beams from SPEAR, in particular the brilliance of undulator radiation, can be improved significantly by reducing the emittance of the stored electron beam. A reduction of the horizontal emittance by a factor of 3.5 to a value of 130 nanometer-radians (nm-r) at 3 GeV has been achieved by using stronger focussing, mainly in the horizontal plane. The low emittance configuration also reduces the dispersion and vertical beta functions in the straight sections, making them more suitable for wigglers. The higher betatron tunes lead to a larger phase advance between the two kickers, which has to be corrected during injection by shunting current from some quadrupoles. The configuration was optimized within SPEAR hardware limitations and tested for dynamic aperture with the tracking program PATRICIA. After implementation of this scheme, beam was successfully injected and accumulated. The measured emittance of the stored beam was in agreement with calculations. Presently the configuration is being made operational

  3. Emittance measurements by variable quadrupole method

    International Nuclear Information System (INIS)

    Toprek, D.

    2005-01-01

    The beam emittance is a measure of both the beam size and beam divergence, we cannot directly measure its value. If the beam size is measured at different locations or under different focusing conditions such that different parts of the phase space ellipse will be probed by the beam size monitor, the beam emittance can be determined. An emittance measurement can be performed by different methods. Here we will consider the varying quadrupole setting method.

  4. Multinozzle emitter arrays for ultrahigh-throughput nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Mao, Pan; Wang, Hung-Ta; Yang, Peidong

    2017-10-17

    The present invention provides for a structure comprising a plurality of emitters, wherein a first nozzle of a first emitter and a second nozzle of a second emitter emit in two directions that are not or essentially not in the same direction; wherein the walls of the nozzles and the emitters form a monolithic whole. The present invention also provides for a structure comprising an emitter with a sharpened end from which the emitter emits; wherein the emitters forms a monolithic whole. The present invention also provides for a fully integrated separation of proteins and small molecules on a silicon chip before the electrospray mass spectrometry analysis.

  5. Alpha emitters activity measurement using the defined solid angle method

    International Nuclear Information System (INIS)

    Blanchis, P.

    1983-01-01

    The defined solid angle counting method can reach a very high accuracy, specially for heavy ions as alpha particles emitted by a radioactive source. The activity measurement of such sources with a relative uncertainty of the order of 0.01% is investigated. Such an accuracy is available only under suitable conditions: the radiation emitted by the source must be isotropic and all the particles emitted in the effective solid angle must be detected. The efficiency detection value must be equal to unity and phenomena such as absorption or scattering must be null. It is shown that corrections often become necessary. All parameters which can influence the measurements are studied [fr

  6. Rayleigh scattering in an emitter-nanofiber-coupling system

    Science.gov (United States)

    Tang, Shui-Jing; Gao, Fei; Xu, Da; Li, Yan; Gong, Qihuang; Xiao, Yun-Feng

    2017-04-01

    Scattering is a general process in both fundamental and applied physics. In this paper, we investigate Rayleigh scattering of a solid-state-emitter coupled to a nanofiber, by S -matrix-like theory in k -space description. Under this model, both Rayleigh scattering and dipole interaction are studied between a two-level artificial atom embedded in a nanocrystal and fiber modes (guided and radiation modes). It is found that Rayleigh scattering plays a critical role in the transport properties and quantum statistics of photons. On the one hand, Rayleigh scattering produces the transparency in the optical transmitted field of the nanofiber, accompanied by the change of atomic phase, population, and frequency shift. On the other hand, the interference between two kinds of scattering fields by Rayleigh scattering and dipole transition modifies the photon statistics (second-order autocorrelation function) of output fields, showing a strong wavelength dependence. This study provides guidance for the solid-state emitter acting as a single-photon source and can be extended to explore the scattering effect in many-body physics.

  7. International workshop on emittance preservation in linear colliders

    International Nuclear Information System (INIS)

    Urakawa, Junji; Oide, Katsunobu

    1993-09-01

    The extremely low emittances, which are the essential feature for any linear collider, are far beyond those of the present high-energy accelerators. Every part of the linear-collider accelerator complex is liable to blow up them to a fatal degree. Above all, the main linac is the most critical part, since it will have an unprecedented length, through which very highly populated bunches should be accelerated without a faint increase of emittances. A lot of efforts have been paid, mainly theoretically, to settle this problem at all institutes. Any convincing conclusions are not yet reached. Furthermore, there are six approaches of substantially different schemes (Tesla, DLC, JLC, NLC, VLEPP, CLIC), each requiring its own way to tackle the problem. In this workshop, many up-to-date R and D results were presented by each institute. Judging from what were discussed, we may well say that the R and D work has advanced to such a level that the different approaches are rather helping each other to reach more concrete results. (J.P.N.)

  8. Hybrid emitter all back contact solar cell

    Science.gov (United States)

    Loscutoff, Paul; Rim, Seung

    2016-04-12

    An all back contact solar cell has a hybrid emitter design. The solar cell has a thin dielectric layer formed on a backside surface of a single crystalline silicon substrate. One emitter of the solar cell is made of doped polycrystalline silicon that is formed on the thin dielectric layer. The other emitter of the solar cell is formed in the single crystalline silicon substrate and is made of doped single crystalline silicon. The solar cell includes contact holes that allow metal contacts to connect to corresponding emitters.

  9. Emittance measurements of the CLIO electron beam

    Science.gov (United States)

    Chaput, R.; Devanz, G.; Joly, P.; Kergosien, B.; Lesrel, J.

    1997-02-01

    We have designed a setup to measure the transverse emittance at the CLIO accelerator exit, based on the "3 gradients" method. The beam transverse size is measured simply by scanning it with a steering coil across a fixed jaw and recording the transmitted current, at various quadrupole strengths. A code then performs a complete calculation of the emittance using the transfer matrix of the quadrupole instead of the usual classical lens approximation. We have studied the influence of various parameters on the emittance: Magnetic field on the e-gun and the peak current. We have also improved a little the emittance by replacing a mismatched pipe between the buncher and accelerating section to avoid wake-field effects; The resulting improvements of the emittance have led to an increase in the FEL emitted power.

  10. 2-D emittance equation with acceleration and compression

    International Nuclear Information System (INIS)

    Hahn, K.D.; Smith, L.

    1988-10-01

    Since both acceleration and compression are required for an Inertial Fusion Driver, the understanding of their effect on the beam quality, emittance, is important. This report attempts to generalize the usual emittance formula for the drifting beam to include these effects. The derivation of the 2-D emittance equation is carried out and a comparison with the particle code results is given. The 2-D emittance at a given axial location is reasonable to consider for a long beam, particularly with velocity tilt; transverse emittance averaged over the entire bunch is not a useful quantity. 6 refs., 2 figs., 1 tab

  11. Analysis of radionuclide mixtures by {alpha}-{gamma} and {beta}-{gamma} coincidences using a simple device; Analyse de melanges de radionucleides par un dispositif simple de coincidences {alpha}-{gamma} et {beta}-{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Pottier, R; Berger, R [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France)

    1966-06-01

    A procedure is described for the qualitative and quantitative spectrographic analysis of radioactive sources containing two alpha-gamma emitters having the same alpha energy or two beta-gamma emitters having the same gamma energy. The main apparatus is a multichannel pulse-height analyzer including a coincidence circuit. The principle of the method, the synoptic scheme, the electronic device, the type of sources, and the precautions to be taken or the corrections to take into account are reported. The results obtained in solving the three following problems are discussed as examples of applications of the method: analysis of {sup 241}Am in alpha-gamma sources containing {sup 238}Pu; analysis of {sup 237}Np in beta-gamma sources containing {sup 239}Pu; and analysis of {sup 106}Ru-{sup 106}Rh in beta-gamma sources containing {sup 95}Zr-{sup 95}Nb. (authors) [French] Dans ce. rapport, on presente une methode d'analyse spectrographique qualitative et quantitative de sources radioactives contenant deux emetteurs alpha-gamma de meme energie alpha et deux emetteurs beta-gamma de meme energie gamma. L'organe principal est un analyseur d'amplitude a 400 canaux comprenant un circuit de coincidence. On decrit le principe de la methode, le schema synoptique, l'appareillage, le type des sources, les precautions a prendre ou les corrections a faire. On discute les resultats obtenus dans la solution des trois problemes suivants traites a titre d'application de la methode: 1. analyse d'americium 241 en presence de plutonium 238; 2. analyse de neptunium 237 en presence de plutonium 239; 3. analyse de ruthenium 106-rhodium 106 en presence de zirconium 95-niobium 95. (auteurs)

  12. Emittance growth in rf linacs

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1979-01-01

    As the space-charge limit is approached, the current that can be accelerated in an rf linac and the output emittance that can be expected are discussed. The role of the envelope equations to estimate limits is outlined. The results of numerical experiments to explore general properties of emittance growth are given

  13. TENORM wastes and the potential alpha radiation dose to aquatic biota

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    2002-01-01

    In the years seventies release-rates and derived limits for releasing radionuclides into the environment were adopted for each particular radionuclide and for a number of pathways. The release-rate limit adopted for alpha emitters was 10 15 Bq.y -1 for a single site, but limited to 10 14 Bq.y -1 for 226 Ra and supported 210 Po. In addition, to meet the requirements of the London Convention, a derived limit should be expressed in terms of concentration, which for alpha emitters was 10 10 Bq.t -1 , but limited to 10 14 Bq.t -1 for 226 Ra and supported 210 Po, assuming an upper limit to the mass dumping rate of 10 5 t per year at a single dumping site. New data on the radioactivity in the marine environment and biota, including plankton, indicated a potential alpha radiation dose to these aquatic organisms due to the release of technologically enhanced naturally occurring radioactive materials (TENORM) wastes. At the highest accumulation of 239 Pu in the zooplankton Gammarus in Thule, Greenland, due to an accidental release associated with military activities, the dose rate reached about 0.14 μGy.h -1 . Such dose rate was similar to that received by the phytoplankton Chaetoceros and Rhizosolenia from Agulhas current, Africa, due to naturally occurring radioactive materials (NORM) supposedly enhanced for almost one century of gold mining at first, and subsequently because of heap-leaching uranium extraction from the tailings left behind by earlier gold miners. The paper will discuss the alpha radiation dose to aquatic biota, in general, and to plankton, in particular, due to potential releases of TENORM wastes in the aquatic environment. (author)

  14. Alpha spectrometry without chemistry

    International Nuclear Information System (INIS)

    Murray, A.S.; Heaton, B.

    1983-01-01

    A gridded cylindrical pulse ionization chamber is considered for the simultaneous analysis of natural alpha emitters. Solid sources of up to 0.3 g are deposited after wet grinding as a thin layer on 1.1 m 2 of aluminized plastic film, which acts as the cathode. No chemistry is involved, and thus there is little chance of nuclide fractionation. With a ''weightless'' source the resolution is about 55 keV; 110 keV has been easily achieved at 4.2 MeV with real sources. We conclude that significant information about isotope activities in the natural series is available with only a fraction of the work involved in conventional techniques. (author)

  15. Minimum emittance in TBA and MBA lattices

    Science.gov (United States)

    Xu, Gang; Peng, Yue-Mei

    2015-03-01

    For reaching a small emittance in a modern light source, triple bend achromats (TBA), theoretical minimum emittance (TME) and even multiple bend achromats (MBA) have been considered. This paper derived the necessary condition for achieving minimum emittance in TBA and MBA theoretically, where the bending angle of inner dipoles has a factor of 31/3 bigger than that of the outer dipoles. Here, we also calculated the conditions attaining the minimum emittance of TBA related to phase advance in some special cases with a pure mathematics method. These results may give some directions on lattice design.

  16. Minimum emittance in TBA and MBA lattices

    International Nuclear Information System (INIS)

    Xu Gang; Peng Yuemei

    2015-01-01

    For reaching a small emittance in a modern light source, triple bend achromats (TBA), theoretical minimum emittance (TME) and even multiple bend achromats (MBA) have been considered. This paper derived the necessary condition for achieving minimum emittance in TBA and MBA theoretically, where the bending angle of inner dipoles has a factor of 3 1/3 bigger than that of the outer dipoles. Here, we also calculated the conditions attaining the minimum emittance of TBA related to phase advance in some special cases with a pure mathematics method. These results may give some directions on lattice design. (authors)

  17. Reggeon field theory for alpha (0)>1

    CERN Document Server

    Amati, Daniele; Le Bellac, M; Marchesini, G

    1976-01-01

    The asymptotic behaviour of the scattering amplitude is obtained when the pomeron has intercept alpha (0) larger than one. The reggeon field theory is studied by introducing a lattice in impact parameter space. Use is made of a previous result showing that asymptotically the dynamics is controlled at each lattice site ( alpha '=0 case) by a two-level structure. This leads to a non-Hermitean Hamiltonian expressed in terms of spin operators in which the intersite interaction term is proportional to the pomeron slope alpha '. The spectrum of such a system shows a degenerate ground state for alpha (0)> alpha /sub c/>or approximately=1 and a continuum with vanishing excitation gap at alpha (0)= alpha /sub c/. The vacuum does not change structure at the critical value. The criticality is shown by an order parameter which is given by the matrix element of a field operator between the vacuum and its degenerate companion. The nature of this critical phenomenon is better understood by continuously transforming the Hami...

  18. Nuclear alpha spectrin: Critical roles in DNA interstrand cross-link repair and genomic stability

    OpenAIRE

    Lambert, Muriel W

    2016-01-01

    Non-erythroid alpha spectrin (?IISp) is a structural protein which we have shown is present in the nucleus of human cells. It interacts with a number of nuclear proteins such as actin, lamin, emerin, chromatin remodeling factors, and DNA repair proteins. ?IISp?s interaction with DNA repair proteins has been extensively studied. We have demonstrated that nuclear ?IISp is critical in DNA interstrand cross-link (ICL) repair in S phase, in both genomic (non-telomeric) and telomeric DNA, and in ma...

  19. Performance comparison of scintillators for alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2014-11-11

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.

  20. Alpha-contaminated waste from reprocessing of nuclear fuel

    International Nuclear Information System (INIS)

    Sumner, W.

    1982-01-01

    The anticipated alpha-waste production rates from the Barnwell Nuclear Fuel Reprocessing plant is discussed. The estimated alpha-waste production rate from the 1500 metric ton/year plant is about 85,000 ft 3 /year at the 10 nCi/g limit. Most of this waste is estimated to come from the separation facility, and the major waste sources were cladding, which was 27%, and low-level contact-handled general process trash, which was estimated at 32% of the total. It was estimated that 45% of the waste was combustible and 72% of the waste was compactible. These characteristics could have a significant impact on the final volumes as disposed. Changing the alpha-waste limit from 10 nCi/g to 100 nCi/g was estimated to reduce the amount of alpha waste produced by about 20%. Again, the uncertainty in this value obviously has to be substantial. One has to recognize that these estimates were just that; they were not based on any operating experience. The total plutonium losses to waste, including the high-level waste, was estimated to be 1.5%. The cladding waste was estimated to be contaminated with alpha emitters to the extent of 10 4 to 10 5 nCi/g

  1. Development of Emittance Analysis Software for Ion Beam Characterization

    International Nuclear Information System (INIS)

    Padilla, M.J.; Liu, Yuan

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a figure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally, a high-quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifield Radioactive Ion Beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profiles, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fitting are also incorporated into the software. The software will provide a simplified, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate

  2. DEVELOPMENT OF EMITTANCE ANALYSIS SOFTWARE FOR ION BEAM CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, M. J.; Liu, Y.

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a fi gure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally a high quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifi eld Radioactive Ion beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profi les, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fi tting are also incorporated into the software. The software will provide a simplifi ed, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate.

  3. Radiolytic oxidation of UO{sub 2} pellets doped with alpha-emitters ({sup 238/239}Pu)

    Energy Technology Data Exchange (ETDEWEB)

    Muzeau, B. [Commissariat a l' Energie Atomique, Rhone Valley Research Center DTCD/SECM/LMPA, BP 17 171, 30207 Bagnols-sur-Ceze Cedex (France); Jegou, C. [Commissariat a l' Energie Atomique, Rhone Valley Research Center DTCD/SECM/LMPA, BP 17 171, 30207 Bagnols-sur-Ceze Cedex (France)], E-mail: christophe.jegou@cea.fr; Delaunay, F. [Commissariat a l' Energie Atomique, Valduc Research Center, 21120 Is-sur-Tille (France); Broudic, V. [Commissariat a l' Energie Atomique, Rhone Valley Research Center DTCD/SECM/LMPA, BP 17 171, 30207 Bagnols-sur-Ceze Cedex (France); Brevet, A. [Commissariat a l' Energie Atomique, Valduc Research Center, 21120 Is-sur-Tille (France); Catalette, H. [Electricite de France, Les Renardieres Research Center, Route de Sens Ecuelles, 77250 Moret-sur-Loing (France); Simoni, E. [Institut de Physique Nucleaire, Bat. 100, 91406 Orsay Cedex (France); Corbel, C. [Laboratoire des Solides Irradies, UMR 7642-CNRS-CEA-Ecole Polytechnique, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2009-01-07

    To assess the impact of alpha radiolysis of water on the oxidative dissolution of UO{sub 2} under anoxic conditions, two series of plutonium-doped samples (specific alpha activity 385 and 18 MBqg{sub UO{sub 2}}{sup -1}) were fabricated, characterized and leached in water of varying complexity (pure water, carbonated water, dissolved hydrogen). Given the very high reactivity of these samples in the presence of air and in order to minimize any prior surface oxidation, a strict experimental protocol was developed based on high-temperature annealing in Ar + 4% H{sub 2} with preleaching cycles. Failure to follow this protocol prevents absolute quantification of oxidation of the UO{sub 2} surface by water radiolysis in solutions. Preoxidation of the pellet surface can lead to uranium release in solution that is dependent on the alpha particle flux, revealing initial oxidation by radiolysis in air including potential traces of water. This makes difficult the accurate quantification of the radiolytic oxidation in water solutions. Controlling the initial surface condition of the samples finally allowed us to demonstrate that radiolytic oxidation in water-saturated media is governed by several threshold effects for which the main parameters are the sample alpha activity and the hydrogen concentration.

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

    International Nuclear Information System (INIS)

    Terini, R.A.

    1991-01-01

    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)

  5. A multislit transverse-emittance diagnostic for space-charge-dominated electron beams

    International Nuclear Information System (INIS)

    Piot, P.; Song, J.; Li, R.

    1997-01-01

    Jefferson Lab is developing a 10 MeV injector to provide an electron beam for a high-power free-electron laser (FEL). To characterize the transverse phase space of the space-charged-dominated beam produced by this injector, the authors designed an interceptive multislit emittance diagnostic. It incorporates an algorithm for phase-space reconstruction and subsequent calculation of the Twiss parameters and emittance for both transverse directions at an update rate exceeding 1 Hz, a speed that will facilitate the transverse-phase-space matching between the injector and the FEL's accelerator that is critical for proper operation. This paper describes issues pertaining to the diagnostic's design. It also discusses the acquisition system, as well as the software algorithm and its implementation in the FEL control system. First results obtained from testing this diagnostic in Jefferson Lab's Injector Test Stand are also included

  6. Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

    Science.gov (United States)

    Watchman, Christopher J.

    Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological

  7. A improved method for the analysis of alpha spectra

    International Nuclear Information System (INIS)

    Equillor, Hugo E.

    2004-01-01

    In this work we describe a methodology, developed in the last years, for the analysis of alpha emitters spectra, obtained with implanted ion detectors, that tend to solve some of the problems that shows this type of spectra. This is an improved methodology respect to that described in a previous publication. The method is based on the application of a mathematical function that allows to model the tail of an alpha peak, to evaluate the part of the peak that is not seen in the cases of partial superposition with another peak. Also, a calculation program that works in a semiautomatic way, with the possibility of interactive intervention of the analyst, has been developed simultaneously and is described in detail. (author)

  8. Quantum efficiency and thermal emittance of metal photocathodes

    Directory of Open Access Journals (Sweden)

    David H. Dowell

    2009-07-01

    Full Text Available Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths with major advances occurring since the invention of the photocathode gun and the realization of emittance compensation. These state-of-the-art electron beams are now becoming limited by the intrinsic thermal emittance of the cathode. In both dc and rf photocathode guns details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship between the quantum efficiency and the thermal emittance for metal cathodes using the Fermi-Dirac model for the electron distribution. We use a consistent theory to derive the quantum efficiency and thermal emittance, and compare our results to those of others.

  9. Beam phase space and emittance

    International Nuclear Information System (INIS)

    Buon, J.

    1990-12-01

    The classical and elementary results for canonical phase space, the Liouville theorem and the beam emittance are reviewed. Then, the importance of phase portraits to obtain a geometrical description of motion is emphasized, with examples in accelerator physics. Finally, a statistical point of view is used to define beam emittance, to study its law of approximate conservation and to treat two particular examples

  10. Monitoring of gross alpha, gross beta and tritium activities in portuguese drinking waters

    International Nuclear Information System (INIS)

    Lopes, I.; Madruga, M.J.; Ferrador, G.O.; Sequeira, M.M.; Oliveira, E.J.; Gomes, A.R.; Rodrigues, F.D.; Carvalho, F.P.

    2006-01-01

    The gross beta and tritium activities in the forty Portuguese drinking waters analyzed using the ISO standard methods (Portuguese Guidelines) are below the guidance levels proposed in the Portuguese Drinking Water Quality Guidelines. In what concerns the gross alpha activity only 18% exceeded the recommended level. In general, it can be concluded that the ingestion of these drinking waters does not create a radiological hazard to the human consumption, however, more detailed analyses will be necessary mainly the determinations of the individual alpha emitters radionuclide concentrations. The minimum gross alpha and gross beta detectable activities by L.S.C. methodology are higher than for the proportional counting technique (ISO method). Higher concentration factors will be needed to reach lower required detection limits. (authors)

  11. Generalized superradiant assembly for nanophotonic thermal emitters

    Science.gov (United States)

    Mallawaarachchi, Sudaraka; Gunapala, Sarath D.; Stockman, Mark I.; Premaratne, Malin

    2018-03-01

    Superradiance explains the collective enhancement of emission, observed when nanophotonic emitters are arranged within subwavelength proximity and perfect symmetry. Thermal superradiant emitter assemblies with variable photon far-field coupling rates are known to be capable of outperforming their conventional, nonsuperradiant counterparts. However, due to the inability to account for assemblies comprising emitters with various materials and dimensional configurations, existing thermal superradiant models are inadequate and incongruent. In this paper, a generalized thermal superradiant assembly for nanophotonic emitters is developed from first principles. Spectral analysis shows that not only does the proposed model outperform existing models in power delivery, but also portrays unforeseen and startling characteristics during emission. These electromagnetically induced transparency like (EIT-like) and superscattering-like characteristics are reported here for a superradiant assembly, and the effects escalate as the emitters become increasingly disparate. The fact that the EIT-like characteristics are in close agreement with a recent experimental observation involving the superradiant decay of qubits strongly bolsters the validity of the proposed model.

  12. Internal emitter research and standard setting

    International Nuclear Information System (INIS)

    Stannard, J.N.

    1981-01-01

    The history of the use of data from internal emitter research in the derivation of safety standards is reviewed. At first, observed biological effects were correlated with body burdens or exposure levels. This direct approach is illustrated by detailed accounts of the cases of uranium and plutonium. In the 1950's, when it was decided to provide standards for over 200 isotopes, the direct approach was replaced by a system of calculations. This necessitated changes in internal emitter research programs to provide metabolic data, and the development of models such as Reference Man and the Lung and Gastrointestinal Tract models. The continuing contribution of internal emitter research to standard setting can be seen in the references quoted in the metabolic data section of the new ICRP report (ICRP Publication 30). Present trends suggest a possible return to the direct use of internal emitter effects data for obtaining risk estimates. (U.K.)

  13. Solid-state single-photon emitters

    Science.gov (United States)

    Aharonovich, Igor; Englund, Dirk; Toth, Milos

    2016-10-01

    Single-photon emitters play an important role in many leading quantum technologies. There is still no 'ideal' on-demand single-photon emitter, but a plethora of promising material systems have been developed, and several have transitioned from proof-of-concept to engineering efforts with steadily improving performance. Here, we review recent progress in the race towards true single-photon emitters required for a range of quantum information processing applications. We focus on solid-state systems including quantum dots, defects in solids, two-dimensional hosts and carbon nanotubes, as these are well positioned to benefit from recent breakthroughs in nanofabrication and materials growth techniques. We consider the main challenges and key advantages of each platform, with a focus on scalable on-chip integration and fabrication of identical sources on photonic circuits.

  14. A low emittance configuration for spear

    International Nuclear Information System (INIS)

    Blumberg, L.N.; Cerino, J.; Harris, J.; Hettel, R.; Hofmann, A.; Liu, R.Z.; Stego, R.; Wiedemann, H.; Winick, H.

    1985-01-01

    The quality of synchrotron radiation beams from SPEAR, in particular the brilliance of undulator radiation, can be improved significantly by reducing the emittance of the stored electron beam. A reduction of the horizontal emittance by a factor of 3.5 to a value of 130 nanometer-radians (nm-r) at 3 GeV has been achieved by using stronger focussing, mainly in the horizontal plane. The low emittance configuration also reduces the dispersion and vertical beta functions in the straight sections, making them more suitable for wigglers. The higher betatron tunes lead to a larger phase advance between the two kickers, which has to be corrected during injection by shunting current from some quadrupoles. The configuration was optimized within SPEAR hardware limitations and tested for dynamic aperture with the tracking program PATRICIA. After implementation of this scheme, beam was successfully injected and accumulated. The measured emittance of the stored beam was in agreement with calculations. Presently the configuration is being made operational

  15. Emittance growth rates for displaced beams

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1993-05-01

    Emittance growth rates have been previously analyzed for nonuniform beams in linear channels and for initially uniform mismatched beams in nonlinear channels. These studies were for centered beams. Additional emittance growth can arise in cases where the beam is initially displaced. The purpose of this study is to obtain growth rates for displaced beams. This work differs from studies involving random displacement of electrodes. Our analysis assumes instead that the focusing system is perfectly aligned but that the beam is initially displaced with respect to the equilibrium axis. If the focusing force is slightly nonlinear, we find a gradual transfer of the potential energy of beam displacement into kinetic energy associated with emittance growth. We present explicit results for the emittance growth distance as a function of the nonlinearity of the channel. These results will have practical importance for designers of accelerators and transport systems when setting realistic tolerances for initial beam alignment. These tolerances will depend on the nonlinearity and the length of the system

  16. Emittance variations in current-amplifying ion induction linacs

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1991-01-01

    Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5-10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20-40 mA per beam are typical. Recent experiments with extremely low emittance beams (var-epsilon n =0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ 0 =72 degree, σ∼6 degree) are difficult to match to the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented

  17. Emittance variations in current-amplifying ion induction linacs

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1991-04-01

    Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5--10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20--40 mA per beam are typical. Recent experiments with extremely low emittance beams (ε n = 0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ o = 72 degrees, σ∼6 degree) are difficult to match the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented. 12 refs., 8 figs

  18. Gamma flux responsive self-powered detector with a tubular emitter

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1982-01-01

    A gamma-sensitive flux detector comprises tubular emitter, an insulating core within the emitter and an insulating layer about the emitter, and a tubular conductive collector electrode about the insulating layer. The emitter material may be platinum, lead, bismuth, tantalum, tungsten; platinum preferred

  19. Emittance Growth in the NLCTA First Chicane

    International Nuclear Information System (INIS)

    Sun, Yipeng

    2011-01-01

    In this paper, the emittance growth in the NLCTA (Next Linear Collider Test Accelerator) first chicane region is evaluated by simulation studies. It is demonstrated that the higher order fields of the chicane dipole magnet and the dipole corrector magnet (which is attached on the quadrupoles) are the main contributions for the emittance growth, especially for the case with a large initial emittance (γε 0 = 5 (micro)m for instance). These simulation results agree with the experimental observations.

  20. A combined emitter threat assessment method based on ICW-RCM

    Science.gov (United States)

    Zhang, Ying; Wang, Hongwei; Guo, Xiaotao; Wang, Yubing

    2017-08-01

    Considering that the tradition al emitter threat assessment methods are difficult to intuitively reflect the degree of target threaten and the deficiency of real-time and complexity, on the basis of radar chart method(RCM), an algorithm of emitter combined threat assessment based on ICW-RCM (improved combination weighting method, ICW) is proposed. The coarse sorting is integrated with fine sorting in emitter combined threat assessment, sequencing the emitter threat level roughly accordance to radar operation mode, and reducing task priority of the low-threat emitter; On the basis of ICW-RCM, sequencing the same radar operation mode emitter roughly, finally, obtain the results of emitter threat assessment through coarse and fine sorting. Simulation analyses show the correctness and effectiveness of this algorithm. Comparing with classical method of emitter threat assessment based on CW-RCM, the algorithm is visual in image and can work quickly with lower complexity.

  1. On the feasibility of sub-100 nm rad emittance measurement in plasma accelerators using permanent magnetic quadrupoles

    Science.gov (United States)

    Li, F.; Wu, Y. P.; Nie, Z.; Guo, B.; Zhang, X. H.; Huang, S.; Zhang, J.; Cheng, Z.; Ma, Y.; Fang, Y.; Zhang, C. J.; Wan, Y.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Gu, Y. Q.

    2018-01-01

    Low emittance (sub-100 nm rad) measurement of electron beams in plasma accelerators has been a challenging issue for a while. Among various measurement schemes, measurements based on single-shot quad-scan using permanent magnetic quadrupoles (PMQs) has been recently reported with emittance as low as ˜200 nm Weingartner (2012 Phys. Rev. Spec. Top. Accel. Beams 15 111302). However, the accuracy and reliability of this method have not been systematically analyzed. Such analysis is critical for evaluating the potential of sub-100 nm rad emittance measurement using any scheme. In this paper, we analyze the effects of various nonideal physical factors on the accuracy and reliability using the PMQ method. These factors include aberration induced by a high order field, PMQ misalignment and angular fluctuation of incoming beams. Our conclusions are as follows: (i) the aberrations caused by high order fields of PMQs are relatively weak for low emittance measurement as long as the PMQs are properly constructed. A series of PMQs were manufactured and measured at Tsinghua University, and using numerical simulations their high order field effects were found to be negligible . (ii) The largest measurement error of emittance is caused by the angular misalignment between PMQs. For low emittance measurement of ˜100 MeV beams, an angular alignment accuracy of 0.1° is necessary. This requirement can be eased for beams with higher energies. (iii) The transverse position misalignment of PMQs and angular fluctuation of incoming beams only cause a translational and rotational shift of measured signals, respectively, therefore, there is no effect on the measured value of emittance. (iv) The spatial resolution and efficiency of the detection system need to be properly designed to guarantee the accuracy of sub-100 nm rad emittance measurement.

  2. Method validation for simultaneous counting of Total α , β in Drinking Water using Liquid Scintillation Counter

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Nashawati, A.

    2014-05-01

    In this work, Method Validation Methods and Pulse Shape Analysis were validated to determine gross Alpha and Beta Emitters in Drinking Water using Liquid Scintillation Counter Win spectral 1414. Validation parameters include Method Detection Limit, Method Quantitation Limit, Repeatability Limit, Intermediate Precision, Trueness) Bias), Recovery Coefficient, Linearity and Uncertainty Budget in analysis. The results show that the Method Detection Limit and Method Quantitation Limit were 0.07, 0.24 Bq/l for Alpha emitters respectively, and 0.42, 1.4 Bq/l for Beta emitters, respectively. The relative standard deviation of Repeatability Limit reached 2.81% for Alpha emitters and 3.96% for Beta emitters. In addition to, the relative standard deviation of Intermediate Precisionis was 0.54% for Alpha emitters and 1.17% for Beta emitters. Moreover, the trueness was - 7.7% for Alpha emitters and - 4.5% for Beta emitters. Recovery Coefficient ranged between 87 - 96% and 88-101 for Alpha and Beta emitters, respectively. Linearity reached 1 for both Alpha and Beta emitters. on the other hand, Uncertainty Budget for all continents was 96.65% ,83.14% for Alpha and Beta emitters, respectively (author).

  3. Recent developments for field monitoring of alpha-emitting contaminants in the environment

    International Nuclear Information System (INIS)

    Ahlquist, A.J.; Umbarger, C.J.; Stoker, A.K.

    1978-01-01

    The Los Alamos Scientific Laboratory has adapted two field methods to assess rapidly locations and concentrations of alpha-emitting contaminants in soil. (1) A ZnS scintillator is used for gross-alpha measurements on soil samples. Sample preparation and the calibration and detection limits of the system are discussed, and results of gross-alpha analysis are compared with results of a 239 Pu radiochemistry analysis. (2) A Phoswich detector is used as a field survey instrument because it can detect lower levels of radioactivity than the FIDLER probe. The electronics are carried in a truck and the probe is connected by an umbilical cord. The system electronics are calibrated with an energy window of 12-40 keV which allows detection of Pu, Am, Th (using daughter L X-rays of the alpha-emitters) and 137 Cs (using its daughter 32 keV X-rays). The bremsstrahlung from 90 Sr can also be detected. (author)

  4. An alpha particle measurement system using an energetic neutral helium beam in ITER (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O. [Graduate school of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Shinto, K. [IFMIF R and D Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2012-02-15

    An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He{sup +} ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He{sup +} ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

  5. Experiences with large-area frisch grid chambers in low-level alpha spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hoetzl, H.; Winkler, R. (Gesellschaft fuer Strahlen- und Umweltforschung m.b.H. Muenchen, Neuherberg (Germany, F.R.). Inst. fuer Strahlenschutz)

    1984-06-15

    The properties of parallel-plate gridded ionization chambers with areas of 300 cm/sup 2/, developed by us for alpha spectrometry of samples with low specific alpha activity are reported. Several practical hints for optimum operating conditions are presented. The chambers can be operated routinely at atmospheric pressure for several days, without the need for purification of the gas filling (P10). The minimum detectable activity at 5 MeV is 0.01 pCi, based on 4.65 standard deviations of background and 1000 min counting time. At the GSF Research Center ionization chambers of this type are used for the analysis of natural alpha emitters, as well as of transuranium nuclides in environmental samples by: a) direct alpha spectrometry without any previous treatment of the sample, b) semi-direct spectrometry after removal of organic matter by low-temperature ashing and c) spectrometry after chemical separation. Some typical example of application are given. Furthermore the range of application of the chambers in comparison to semiconductor detectors in the field of low-level alpha spectrometry is discussed.

  6. Experiences with large-area frisch grid chambers in low-level alpha spectrometry

    International Nuclear Information System (INIS)

    Hoetzl, H.; Winkler, R.

    1984-01-01

    The properties of parallel-plate gridded ionization chambers with areas of 300 cm 2 , developed by us for alpha spectrometry of samples with low specific alpha activity are reported. Several practical hints for optimum operating conditions are presented. The chambers can be operated routinely at atmospheric pressure for several days, without the need for purification of the gas filling (P10). The minimum detectable activity at 5 MeV is 0.01 pCi, based on 4.65 standard deviations of background and 1000 min counting time. At the GSF Research Center ionization chambers of this type are used for the analysis of natural alpha emitters, as well as of transuranium nuclides in environmental samples by: a) direct alpha spectrometry without any previous treatment of the sample, b) semi-direct spectrometry after removal of organic matter by low-temperature ashing and c) spectrometry after chemical separation. Some typical example of application are given. Furthermore the range of application of the chambers in comparison to semiconductor detectors in the field of low-level alpha spectrometry is discussed. (orig.)

  7. Single-shot measurements of low emittance beams from laser-plasma accelerators comparing two triggered injection methods

    Science.gov (United States)

    van Tilborg, Jeroen

    2017-10-01

    The success of laser plasma accelerator (LPA) based applications, such as a compact x-ray free electron laser (FEL), relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot energy-dispersed emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock-induced density down-ramp injection. Both injection mechanisms have gained in popularity in recent years due to their demonstrated stable LPA performance. For the down-ramp injection configuration, normalized emittances a factor of two lower were recorded: less than 1 micron at spectral charge densities up to 2 pC/MeV. For both injection mechanisms, a contributing correlation of space charge to the emittance was identified. This measurement technique in general, and these results specifically, are critical to the evaluation of LPA injection methods and development of high-quality LPA beam lines worldwide. This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the U.S. DOE NNSA, DNN R&D (NA22), by the National Science Foundation under Grant No. PHY-1415596, and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

  8. Measurements of Thermal Emittance for Cesium Telluride Photocathodes at PITZ

    CERN Document Server

    Miltchev, V; Grabosch, H J; Han, J H; Krasilnikov, M; Oppelt, A; Petrosian, B; Staykov, L; Stephan, F

    2005-01-01

    The thermal emittance determines the lower emittance limit and its measurement is of high importance to understand the ultimate injector performance. In this contribution we present results of thermal emittance measurements under rf operation conditions for various Cs2Te cathodes and different accelerating gradients. Measurements of thermal emittance scaling with the cathode laser spot size are presented and analysed. The significance of the Schottky effect in the emittance formation process is discussed.

  9. Preparation and preclinical evaluation of {sup 211}At-labelled compounds for {alpha}-particle radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R H

    1994-12-31

    The interest for {alpha}-particle emitters in internal radiotherapy is increasing due to improved conjugation chemistry. Experimental work has concentrated on {sup 211}At and {sup 212}Bi since these to nuclides have radiochemical and physical properties suitable for medical application. In this report it is demonstrated that biologically active {sup 211}At-labelled compounds can be prepared within a relatively short time allowing utilization of this 7.2 h {alpha}-particle. It is further shown that {sup 211}At-TP-3 treatment of human osteosarcoma in vitro gives promising therapeutic ratios. 76 refs., 5 figs., 3 tabs.

  10. Electron emitter pulsed-type cylindrical IEC

    International Nuclear Information System (INIS)

    Miley, G.H.; Gu, Y.; Stubbers, R.; Zich, R.; Anderl, R.; Hartwell, J.

    1997-01-01

    A cylindrical version of the single grid Inertial Electrostatic Confinement (IEC) device (termed the C-device) has been developed for use as a 2.5-MeV D-D fusion neutron source for neutron activation analysis. The C-device employs a hollow-tube type cathode with similar anodes backed up by ''reflector'' dishes. The resulting discharge differs from a conventional hollow cathode discharge, by creating an explicit ion beam which is ''pinched'' in the cathode region. Resulting fusion reactions generate ∼10 6 neutron/s. A pulsed version is under development for applications requiring higher fluxes. Several pulsing techniques are under study, including an electron emitter (e-emitter) assisted discharge in a thorated tungsten wire emitter located behind a slotted area in the reflector dishes. Pulsing is initiated after establishing a low power steady-state discharge by pulsing the e-emitter current using a capacitor switch type circuit. The resulting electron jet, coupled with the discharge by the biased slot array, creates a strong pulse in the pinched ion beam. The pulse length/repetition rate are controlled by the e-emitter pulse circuit. Typical parameters in present studies are ∼30micros, 10Hz and 1-amp ion current. Corresponding neutron measurements are an In-foil type activation counter for time averaged rates. Results for a wide variety of operating conditions are presented

  11. Emittance and beam size distortion due to linear coupling

    International Nuclear Information System (INIS)

    Parzen, G.

    1993-01-01

    At injection, the presence of linear coupling may result in an increased beam emittance and in increased beam dimensions. Results for the emittance in the presence of linear coupling will be found. These results for the emittance distortion show that the harmonics of the skew quadrupole field close to ν x + ν y are the important harmonics. Results will be found for the important driving terms for the emittance distortion. It will be shown that if these driving terms are corrected, then the total emittance is unchanged, var-epsilon x + var-epsilon y = var-epsilon 1 + var-epsilon 2 . Also, the increase in the beam dimensions will be limited to a factor which is less than 1.414. If the correction is good enough, see below for details, one can achieve var-epsilon 1 = var-epsilon x , var-epsilon 2 = var-epsilon where var-epsilon 1 , var-epsilon 2 are the emittances in the presence of coupling, and the beam dimensions are unchanged. Global correction of the emittance and beam size distortion appears possible

  12. Radiation dosimetry in radiotherapy with internal emitters

    International Nuclear Information System (INIS)

    Stabin, Michael G.

    1997-01-01

    Full text. Radiation dosimetry radionuclides are currently being labeled to various biological agents used in internal emitter radiotherapy. This talk will review the various technologies and types of radiolabel in current use, with focus on the characterization of the radiation dose to the various important tissues of the body. Methods for obtaining data, developing kinetic models, and calculating radiation doses will be reviewed. Monoclonal antibodies are currently being labeled with both alpha and beta emitting radionuclides in attempts to find effective agents against cancer. Several radionuclides are also being used as bone pain palliation agents. These agents must be studied in clinical trials to determine the biokinetics and radiation dosimetry prior to approval for general use. In such studies, it is important to ensure the collection of the appropriate kinds of data and to collect the data at appropriate time intervals. The uptake and retention of activity in all significant source organs and in excreta be measured periodically (with at least 2 data points phase of uptake or clearance). Then, correct dosimetry methods must be applied - the best available methods for characterizing the radionuclide kinetic and for estimating the dosimetry in the various organs of the body especially the marrow, should be used. Attempts are also under way to develop methods for estimating true patient-specific dosimetry. Cellular and animal studies are also. Valuable in evaluating the efficacy of the agents in shrinking or eliminating tumors; some results from such studies will also be discussed. The estimation of radiation doses to patients in therapy with internal emitters involves several complex phases of analysis. Careful attention to detail and the use of the best available methods are essential to the protection of the patient and a successful outcome

  13. Suppression of the emittance growth induced by coherent synchrotron radiation in triple-bend achromats

    International Nuclear Information System (INIS)

    Huang Xiyang; Jiao Yi; Xu Gang; Cui Xiaohao

    2015-01-01

    The coherent synchrotron radiation (CSR) effect in a bending path plays an important role in transverse emittance dilution in high-brightness light sources and linear colliders, where the electron beams are of short bunch length and high peak current. Suppression of the emittance growth induced by CSR is critical to preserve the beam quality and help improve the machine performance. It has been shown that the CSR effect in a double-bend achromat (DBA) can be analyzed with the two-dimensional point-kick analysis method. In this paper, this method is applied to analyze the CSR effect in a triple-bend achromat (TBA) with symmetric layout, which is commonly used in the optics designs of energy recovery linacs (ERLs). A condition of cancelling the CSR linear effect in such a TBA is obtained, and is verified through numerical simulations. It is demonstrated that emittance preservation can be achieved with this condition, and to a large extent, has a high tolerance to the fluctuation of the initial transverse phase space distribution of the beam. (authors)

  14. The Quantum Efficiency and Thermal Emittance of Metal Photocathodes

    International Nuclear Information System (INIS)

    Dowell, D.

    2009-01-01

    Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths, with the principle improvements occurring since the invention of the photocathode gun. The state-of-the-art normalized emittance electron beams are now becoming limited by the thermal emittance of the cathode. In both DC and RF photocathode guns, details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship between the quantum efficiency and the thermal emittance of metal cathodes using the Fermi-Dirac model for the electron distribution. We derive the thermal emittance and its relationship to the quantum efficiency, and compare our results to those of others

  15. Dietary intake and body content of natural uranium

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The members of the uranium series found in the body that arise primarily from dietary intake are 238 U, 234 U, 226 Ra and 210 Pb. Lead 210, the predominant series radionuclide in the body, decays to the alpha emitter 210 Po, while the others are alpha emitters themselves. While 210 Pb primarily enters the body through diet, inhalation must also be considered, especially in smokers. The primary site of deposition for these nuclides is the skeleton and the dose to bone is the critical factor. In this section, the average background, elevated natural and enhanced dietary intakes of the uranium series radionuclides are discussed. Human skeletal levels and consequent alpha doses are summarized

  16. Microdistribution of uranium in kidney using alpha radiography of body animal

    International Nuclear Information System (INIS)

    Cebrian, D.; Morcillo, M. A.

    2006-01-01

    The radiation dose estimation after an internal contamination by a radionuclide requires the use of biokinetic and dosimetric models, which provide the tools for its calculation. The detailed knowledge of the biokinetic behaviour of the corresponding radionuclide is needed in order to build these models. Laboratory animals are employed to get this knowledge. In this context, the use of appropriate radioactivity measurement techniques is important to follow the distribution of the radionuclide within the organism. In this study an animal model of rat treated with uranyl citrate has been used. Sections of the whole animal are made at different times post-administration, and alpha autoradiography is performed with the slices in order to study the microdistribution of the uranium in the kidney. the utility of the alpha autoradiography whole body animal sections for the detailed study of the alpha emitters biodistribution is shown. (Author) 16 refs

  17. Performances of the Alpha-X RF gun on the PHIL accelerator at LAL

    Energy Technology Data Exchange (ETDEWEB)

    Vinatier, T., E-mail: vinatier@lal.in2p3.fr [Laboratoire de l' Accélérateur Linéaire (LAL), Université Paris Sud, UMR 8607, bâtiment 200, 91898 Orsay Cedex (France); Bruni, C. [Laboratoire de l' Accélérateur Linéaire (LAL), Université Paris Sud, UMR 8607, bâtiment 200, 91898 Orsay Cedex (France); Roux, R. [Laboratoire de l' Accélérateur Linéaire (LAL), Université Paris Sud, UMR 8607, bâtiment 200, 91898 Orsay Cedex (France); Laboratoire d' Etude des Eléments Légers, CEA IRAMIS, bâtiment 524, 91191 Gif sur Yvette Cedex (France); Brossard, J. [Laboratoire de l' Accélérateur Linéaire (LAL), Université Paris Sud, UMR 8607, bâtiment 200, 91898 Orsay Cedex (France); Laboratoire Astroparticule et Cosmologie, Université Paris 7, UMR 7164, bâtiment Condorcet, 75205 Paris Cedex (France); Chancé, S.; Cayla, J.N.; Chaumat, V. [Laboratoire de l' Accélérateur Linéaire (LAL), Université Paris Sud, UMR 8607, bâtiment 200, 91898 Orsay Cedex (France); and others

    2015-10-11

    The Alpha-X RF-gun was designed to produce an ultra-short (<100 fs rms), 100 pC and 6.3 MeV electron beam with a normalized rms transverse emittance of 1π mm mrad for a gun peak accelerating field of 100 MV/m. Such beams will be required by the Alpha-X project, which aims to study a laser-driven plasma accelerator with a short wavelength accelerating medium. It has been demonstrated on PHIL (Photo-Injector at LAL) that the coaxial RF coupling, chosen to preserve the gun field cylindrical symmetry, is perfectly understood and allows reaching the required peak accelerating field of 100 MV/m giving beam energy of 6.3 MeV. Moreover, a quite low beam rms relative energy spread of 0.15% at 3.8 MeV has been measured, completely agreeing with simulations. Dark current, quantum efficiencies and dephasing curves measurements have also been performed. They all show high values of the field enhancement factor β, which can be explained by the preparation of the photocathodes. Finally, measurements on the transverse phase-space have been carried out, with some limitations given by the difficult modelization of one of the PHIL solenoid magnets and by the enlargement of the beam transverse dimensions due to the use of YAG screens. These measurements give a normalized rms transverse emittance around 5π mm mrad, which does not fulfill the requirement for the Alpha-X project.

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

    International Nuclear Information System (INIS)

    Tobias, C.C.B.

    1987-01-01

    The absolute activity of U-235 contained in a U 3 O 8 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 1 1/2'' 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) [pt

  19. Alpha liquid scintillation counting: past, present, and future

    International Nuclear Information System (INIS)

    McDowell, W.J.

    1979-01-01

    Beta liquid scintillation counting has been used for about 30 years, and its effectiveness for alpha particles has been known for almost that long; however, the technique has not been widely applied to alpha particle detection because of poor energy resolution, high background, and variable interference from beta and gamma radiation. Beginning with the work of Horrocks in the early 1960s, improvements in energy resolution and background rejection have been made. Further developments at Oak Ridge National Laboratory over the past 10 to 12 years have resulted in improved methods of sample preparation (using liquid-liquid extraction methods to isolate the sample and introduce it into the scintillator) and better instrumentation, including electronic rejection of beta and gamma pulses. Energy resolutions of 200- to 300-keV FWHM and background counts of 0.01 cpm are now routine. Alpha liquid scintillation spectrometry is now suitable for a wide range of applications, from the accurate quantitative determination of relatively large amounts of known nuclides in laboratory-generated samples to the detection and identification of very small, subpicocurie amounts of alpha emitters in environmental-type samples. Suitable nuclide separation procedures, sample preparation methods, and instrument configurations are outlined for a variety of analyses

  20. Diamondoid monolayers as electron emitters

    Science.gov (United States)

    Yang, Wanli [El Cerrito, CA; Fabbri, Jason D [San Francisco, CA; Melosh, Nicholas A [Menlo Park, CA; Hussain, Zahid [Orinda, CA; Shen, Zhi-Xun [Stanford, CA

    2012-04-10

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  1. Nanodiamond Emitters of Single Photons

    Directory of Open Access Journals (Sweden)

    Vlasov I.I.

    2015-01-01

    Full Text Available Luminescence properties of single color centers were studied in nanodiamonds of different origin. It was found that single photon emitters could be realized even in molecularsized diamond (less than 2 nm capable of housing stable luminescent center “silicon-vacancy.” First results on incorporation of single-photon emitters based on luminescent nanodiamonds in plasmonic nanoantennas to enhance the photon count rate and directionality, diminish the fluorescence decay time, and provide polarization selectivity are presented.

  2. Tolerances for the vertical emittance in damping rings

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1991-11-01

    Future damping rings for linear colliders will need to have very small vertical emittances. In the limit of low beam current, the vertical emittance is primarily determined by the vertical dispersion and the betatron coupling. In this paper, the contributions to these effects from random misalignments are calculated and tolerances are derived to limit the vertical emittance with a 95% confidence level. 10 refs., 5 figs

  3. Beam emittance measurements on multicusp ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Sarstedt, M.; Lee, Y.; Leung, K.N. [and others

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 {mu}m patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma.

  4. Beam emittance measurements on multicusp ion sources

    International Nuclear Information System (INIS)

    Sarstedt, M.; Lee, Y.; Leung, K.N.

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 μm patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma

  5. Proposal of a weight factor for alpha radiation aiming biota radioprotection

    International Nuclear Information System (INIS)

    Pereira, Wagner de S.; Py Junior, Delcy de A.; Kelecom, Alphonse; Goncalves, Simone

    2009-01-01

    Several proposals based on the environmental radioprotection of calculating the absorbed dose in biota have been suggested. The absorbed dose expresses the deposition of energy per mass unit. The differences in biological effects of the absorbed dose can be quantified by applying a correction factor to the absorbed dose. The correction factor for radiation is easier to establish, because radiations exist in smaller number (alpha, beta, neutrons and photons) and can be set for groups of organisms. This work aims to propose a correction factor for radiation, in order to adequate the concept of absorbed dose currently used to the concept of equivalent dose. A survey of the literature on correction factors proposed for alpha radiation was carried out and, when possible, the biological endpoint was identified, as well as the radionuclide and the biological target. A variation of the weight factor for alpha radiation from 1 to 377 was observed and a number of biological endpoints, biological target and alpha emitter radionuclide were identified. Finally we propose a weight value for alpha radiation of 40, and we propose also the name of correction factor for radiation alpha as being ecological radiation weighting factor (WRE) the name 'equivalent dose for flora and fauna' (HTFF) to name of the new dose. (author)

  6. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    1996-01-01

    The Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Tm), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, Tecogen, a division of Thermo Power Corporation, a Thermo Electron company, is developing a real-time, field-deployable, alpha monitor based on a solid-state silicon wafer semiconductor (patent pending, to be assigned to the Department of Energy). The Thermo Alpha Monitor (TAM) will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste Focus Area and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This instrument for direct counting of alpha-emitters in aqueous streams is presently being developed by Thermo Power under a development program funded by the DOE Environmental Management program (DOE-EM), administered by the Morgantown Energy Technology Center (METC). Under this contract, Thermo Power has demonstrated a solid-state, silicon-based semiconductor instrument, which uses a proprietary film-based collection system to quantitatively extract the

  7. Test results on two thermionic converters with cermet emitters

    International Nuclear Information System (INIS)

    Saunders, M.; Danielson, L.; Huffman, F.

    1983-01-01

    An emitter made of a directionally solidified Mo-Al 2 O 3 , Cr 2 O 3 eutectic was provided by Eindhoven University of Technology in Eindhoven, The Netherlands. Although the high temperature braze cycle used in bonding this electrode to the emitter substrate destroyed its characteristic needle microstructure, the converter gave good performance. Apparently, chemical species evaporated from the emitter onto the collector provided a low collector work function. The resulting low barrier indices suggest that this surface is a promising emitter

  8. Fitting of alpha-efficiency versus quenching parameter by exponential functions in liquid scintillation counting

    International Nuclear Information System (INIS)

    Sosa, M.; Manjón, G.; Mantero, J.; García-Tenorio, R.

    2014-01-01

    The objective of this work is to propose an exponential fit for the low alpha-counting efficiency as a function of a sample quenching parameter using a Quantulus liquid scintillation counter. The sample quenching parameter in a Quantulus is the Spectral Quench Parameter of the External Standard (SQP(E)), which is defined as the number of channel under which lies the 99% of Compton spectrum generated by a gamma emitter ( 152 Eu). Although in the literature one usually finds a polynomial fitting of the alpha counting efficiency, it is shown here that an exponential function is a better description. - Highlights: • We have studied the quenching in alpha measurement by liquid scintillation counting. • We have reviewed typical fitting of alpha counting efficiency versus quenching parameter. • Exponential fitting of data is proposed as better fitting. • We consider exponential fitting has a physical basis

  9. Fitting of alpha-efficiency versus quenching parameter by exponential functions in liquid scintillation counting

    Energy Technology Data Exchange (ETDEWEB)

    Sosa, M. [Departamento de Ingeniería Física, Campus León, Universidad de Guanajuato, 37150 León, Guanajuato (Mexico); Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain); Manjón, G., E-mail: manjon@us.es [Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain); Mantero, J.; García-Tenorio, R. [Universidad de Sevilla, Departamento de Física Aplicada II, E.T.S. Arquitectura, Av. Reina Mercedes, 2, 41012 Sevilla (Spain)

    2014-05-01

    The objective of this work is to propose an exponential fit for the low alpha-counting efficiency as a function of a sample quenching parameter using a Quantulus liquid scintillation counter. The sample quenching parameter in a Quantulus is the Spectral Quench Parameter of the External Standard (SQP(E)), which is defined as the number of channel under which lies the 99% of Compton spectrum generated by a gamma emitter ({sup 152}Eu). Although in the literature one usually finds a polynomial fitting of the alpha counting efficiency, it is shown here that an exponential function is a better description. - Highlights: • We have studied the quenching in alpha measurement by liquid scintillation counting. • We have reviewed typical fitting of alpha counting efficiency versus quenching parameter. • Exponential fitting of data is proposed as better fitting. • We consider exponential fitting has a physical basis.

  10. Deep rest-frame far-UV spectroscopy of the giant Lyman α emitter 'Himiko'

    DEFF Research Database (Denmark)

    Zabl, J.; Nørgaard-Nielsen, Hans Ulrik; Fynbo, J. P. U.

    2015-01-01

    We present deep 10 h VLT/XSHOOTER spectroscopy for an extraordinarily luminous and extended Ly alpha emitter at z = 6.595 referred to asHimiko and first discussed by Ouchi et al., with the purpose of constraining the mechanisms powering its strong emission. Complementary to the spectrum, we discuss...... near-infrared imaging data from the CANDELS survey. We find neither for He II nor any metal line a significant excess, with 3 σ upper limits of 6.8, 3.1, and 5.8 x 10-18 erg s-1 cm-2 for C IV λ 1549, He II λ 1640, C III] λ 1909, respectively, assuming apertures with 200 km s-1 widths and offset by -250...

  11. Design and device construction for plane tables preparation for counter alpha/beta total

    International Nuclear Information System (INIS)

    Galicia C, F. J.; Monroy G, F.

    2014-10-01

    This work presents the design and assembly of a device for plane tables preparation for quantification alpha/beta total of radioactive waste samples. The determination of the activity index alpha/beta total is used to detect a wide variety of matrices quickly and the concentration of alpha and/or beta emitters of the contained radionuclides in different samples. In particular, the determination of the activity index alpha and beta total of radioactive wastes involves the digestion of samples in aggressive means that will be evaporated to dryness for its quantification. With the purpose of controlling the emission of corrosive gases during the preparation of the plane tables for the quantification of the index alpha and beta total, was designed and built the device in the Radioactive Waste Laboratory that allows to prepare plane tables for proportional counters in a sure and efficient way. The device is constituted by heating equipment, evaporation cylinder and a gases cleaning system. The self-absorption curve got ready starting from the device. (Author)

  12. Transverse emittance growth in staged laser-wakefield acceleration

    Directory of Open Access Journals (Sweden)

    T. Mehrling

    2012-11-01

    Full Text Available We present a study on the emittance evolution of electron bunches, externally injected into laser-driven plasma waves using the three-dimensional particle-in-cell (PIC code OSIRIS. Results show order-of-magnitude transverse emittance growth during the injection process, if the electron bunch is not matched to its intrinsic betatron motion inside the wakefield. This behavior is supported by analytic theory reproducing the simulation data to a percent level. The length over which the full emittance growth develops is found to be less than or comparable to the typical dimension of a single plasma module in current multistage designs. In addition, the analytic theory enables the quantitative prediction of emittance degradation in two consecutive accelerators coupled by free-drift sections, excluding this as a scheme for effective emittance-growth suppression, and thus suggests the necessity of beam-matching sections between acceleration stages with fundamental implications on the overall design of staged laser-wakefield accelerators.

  13. Emittance measurements in Grumman 1 MeV beamline

    International Nuclear Information System (INIS)

    Debiak, T.; Gammel, G.; Melnychuk, S.

    1992-01-01

    The emittance of a 30 keV H - beam has been measured with an Allison type electrostatic analyser at two positions separated by 85 cm along the Grumman 1 MeV beamline LEBT at low currents (about 4 mA, no Cs 2 O additive in the source) and at higher currents (10-15 mA, with Cs 2 O additive in the source). No emittance growth was observed between the two positions, but, at the higher current level, the emittance was about 60% higher than at the low current level (Σ n ,rms = .0045 π cm-mrad vs. 0070 π cm-mrad). Argon was then introduced up to a partial pressure of 4x10 -5 torr, and the emittance decreased back to a range corresponding to that found at the lower currents. However, beam noise was observed at the downstream position, and there is evidence for a small amount of emittance growth (<20%) between the two positions

  14. Emittance Growth during Bunch Compression in the CTF-II

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, Tor O

    1999-02-26

    Measurements of the beam emittance during bunch compression in the CLIC Test Facility (CTF-II) are described. The measurements were made with different beam charges and different energy correlations versus the bunch compressor settings which were varied from no compression through the point of full compression and to over-compression. Significant increases in the beam emittance were observed with the maximum emittance occurring near the point of full (maximal) compression. Finally, evaluation of possible emittance dilution mechanisms indicate that coherent synchrotron radiation was the most likely cause.

  15. Electrohydrodynamic emitters of ion beams

    International Nuclear Information System (INIS)

    Dudnikov, V.G.; Shabalin, A.L.

    1990-01-01

    Physical processes determining generation of ion beams with high emission current density in electrohydrodynamic emitters are considered. Electrohydrodynamic effects developing in ion emission features and kinetics of ion interaction in beams with high density are discussed. Factors determining the size of the emission zone, emission stability at high and low currents, cluster generation, increase of energy spread and decrease of brightness are analyzed. Problems on practical provision of stable EHD emitter functioning are considered. 94 refs.; 8 figs.; 1 tab

  16. Emittance measurements in low energy ion storage rings

    Science.gov (United States)

    Hunt, J. R.; Carli, C.; Resta-López, J.; Welsch, C. P.

    2018-07-01

    The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurement faces several challenges: non-zero dispersion, non-Gaussian beam distributions due to effects of the electron cooler and various systematic errors such as closed orbit offsets and inaccurate rms momentum spread estimation. In addition, diffusion processes, such as intra-beam scattering might lead to emittance overestimates. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA.

  17. Coaching the alpha male.

    Science.gov (United States)

    Ludeman, Kate; Erlandson, Eddie

    2004-05-01

    Highly intelligent, confident, and successful, alpha males represent about 70% of all senior executives. Natural leaders, they willingly take on levels of responsibility most rational people would find overwhelming. But many of their quintessential strengths can also make alphas difficult to work with. Their self-confidence can appear domineering. Their high expectations can make them excessively critical. Their unemotional style can keep them from inspiring their teams. That's why alphas need coaching to broaden their interpersonal tool kits while preserving their strengths. Drawing from their experience coaching more than 1,000 senior executives, the authors outline an approach tailored specifically for the alpha. Coaches get the alpha's attention by inundating him with data from 360-degree feedback presented in ways he will find compelling--both hard-boiled metrics and vivid verbatim comments from colleagues about his strengths and weaknesses. A 360-degree assessment is a wake-up call for most alphas, providing undeniable proof that their behavior doesn't work nearly as well as they think it does. That paves the way for a genuine commitment to change. In order to change, the alpha must venture into unfamiliar--and often uncomfortable--psychological territory. He must admit vulnerability, accept accountability not just for his own work for others', connect with his underlying emotions, learn to motivate through a balance of criticism and validation, and become aware of unproductive behavior patterns. The goal of executive coaching is not simply to treat the alpha as an individual problem but to improve the entire team dynamic. Initial success creates an incentive to persevere, and the virtuous cycle reverberates throughout the entire organization.

  18. Transverse emittance measurement and preservation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Maria

    2016-06-20

    The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle physics. The luminosity production is closely linked to emittance preservation in the accelerator. The transverse emittance is the phase space density of the beam and should be conserved when the particle beam is transformed through the accelerator. Perturbing effects, however, can lead to emittance increase and hence luminosity degradation. Measuring the emittance growth is a complex task with high intensity beams and changing energies. The machine optics and the transverse beam size have to be measured as accurately as possible. Beta function measurements with k-modulation are discussed. With this method the quadrupole focussing strength is varied and the resulting tune change is traced to determine the beta function at the quadrupole. A new k-modulation measurement tool was developed for the LHC. The fully automatic and online measurement system takes constraints of various systems such as tune measurement precision and powering limitations of the LHC superconducting circuits into account. With sinusoidal k-modulation record low beta function measurement uncertainties in the LHC have been reached. 2015 LHC beta function and β*, which is the beta function at the collision point, measurements with k-modulation will be presented. Wire scanners and synchrotron light monitors are presently used in the LHC to measure the transverse beam size. Accuracy and limitations of the LHC transverse profile monitors are discussed. During the 2012 LHC proton run it was found that wire scanner photomultiplier saturation added significant uncertainty on all measurements. A large discrepancy between emittances from wire scanners and luminosity was discovered but not solved. During Long Shutdown 1 the wire scanner system was upgraded with new photomultipliers. A thorough study of LHC wire scanner measurement precision in 2015 is presented

  19. Improvements in emittance wake field optimization for the SLAC Linear Collider

    CERN Document Server

    Decker, Franz Josef

    2003-01-01

    The transverse emittances in the SLAC Linear Collider can be severely diluted by collective wakefield effects and dispersion. For the 1997/98 SLC/SLD run important changes were implemented in the way the emittance is optimized. Early in the linac, where the energy spread is large due to BNS damping, the emittance growth is dominated by dispersion. In this regime emittance tuning bumps may introduce additional wakefield tails and their use is now avoided. At the end of the linac the energy spread is minimal and the emittance measurement is most sensitive to wakefield emittance dilution. In previous years, the emittances were tuned on wire scanners located near but not at the end of the linac (after about 90% of its length). Simulations show that emittance growth of up to 100% can occur in the remaining 10%. In this run wire scanners at the entrance of the Final Focus, the last place where the emittances can be measured, were used for the optimization. Screens at the end of the linac allow additional real time ...

  20. Emittance calculations for the Stanford Linear Collider injector

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Clendenin, J.E.; Helm, R.H.; Lee, M.J.; Miller, R.H.; Blocker, C.A.

    1983-03-01

    A series of measurements have been performed to determine the emittance of the high intensity, single bunch beam that is to be injected into the Stanford Linear Collider. On-line computer programs were used to control the Linac for the purpose of data acquisition and to fit the data to a model in order to deduce the beam emittance. This paper will describe the method of emittance calculation and present some of the measurement results

  1. Local Control of Lung Derived Tumors by Diffusing Alpha-Emitting Atoms Released From Intratumoral Wires Loaded With Radium-224

    International Nuclear Information System (INIS)

    Cooks, Tomer; Schmidt, Michael; Bittan, Hadas; Lazarov, Elinor; Arazi, Lior; Kelson, Itzhak; Keisari, Yona

    2009-01-01

    Purpose: Diffusing alpha-emitters radiation therapy (DART) is a new form of brachytherapy enabling the treatment of solid tumors with alpha radiation. The present study examines the antitumoral effects resulting from the release of alpha emitting radioisotopes into solid lung carcinoma (LL2, A427, and NCI-H520). Methods and Materials: An in vitro setup tested the dose-dependent killing of tumor cells exposed to alpha particles. In in vivo studies, radioactive wires (0.3 mm diameter, 5 mm long) with 224 Ra activities in the range of 21-38 kBq were inserted into LL/2 tumors in C57BL/6 mice and into human-derived A427 or NCI-H520 tumors in athymic mice. The efficacy of the short-lived daughters of 224 Ra to produce tumor growth retardation and prolong life was assessed, and the spread of radioisotopes inside tumors was measured using autoradiography. Results: The insertion of a single DART wire into the center of 6- to 7-mm tumors had a pronounced retardation effect on tumor growth, leading to a significant inhibition of 49% (LL2) and 93% (A427) in tumor development and prolongations of 48% (LL2) in life expectancy. In the human model, more than 80% of the treated tumors disappeared or shrunk. Autoradiographic analysis of the treated sectioned tissue revealed the intratumoral distribution of the radioisotopes, and histological analysis showed corresponding areas of necrosis. In vitro experiments demonstrated a dose-dependent killing of tumors cells exposed to alpha particles. Conclusions: Short-lived diffusing alpha-emitters produced tumor growth retardation and increased survival in mice bearing lung tumor implants. These results justify further investigations with improved dose distributions.

  2. Beam emittance measurement from CERN thermionic guns

    International Nuclear Information System (INIS)

    Kester, O.; Rao, R.; Rinolfi, L.

    1992-01-01

    In the LEP Injector Linacs (LIL) a thermionic gun provides electron beams with different peak intensities at an energy of 80 keV. The beam emittances were estimated from the EGUN programme. Since the gun is of triode type, the main contribution to the emittance comes from the grid. The simulation programme does not model the real geometry by assuming a cylindrical symmetry, while the grid does not have such symmetry. A Gun Test Facility (GTF), allowing emittance measurements, based on the 3-gradients-method was installed. The experimental results are presented. (author) 6 refs.; 6 figs

  3. Multi-dimensional beam emittance and β-functions

    International Nuclear Information System (INIS)

    Buon, J.

    1993-05-01

    The concept of r.m.s. emittance is extended to the case of several degrees of freedom that are coupled. That multi-dimensional emittance is lower than the product of the emittances attached to each degree of freedom, but is conserved in a linear motion. An envelope-hyperellipsoid is introduced to define the β-functions of the beam envelope. On the contrary of an one-degree of freedom motion, it is emphasized that these envelope functions differ from the amplitude functions of the normal modes of motion as a result of the difference between the Liouville and Lagrange invariants. (author) 4 refs

  4. Alpha low activity determination from limitter isotopes of uranium, thorium ands radium in natural waters

    International Nuclear Information System (INIS)

    Gascon, J.L.; Crespo, M.T.; Acena, M.L.

    1989-01-01

    A method to concentrate uranium, thorium and radium in natural waters has been developed. The method, based on the adsorbing propert-ies of manganes dioxide, has been applied to determine the alpha emitter isotopes of these elements in drinking water of Madrid. In this work we present the description of the method, the analytical procedu-res and the obtained results. (Author)

  5. Beam phase space and emittance

    International Nuclear Information System (INIS)

    Buon, J.

    1992-02-01

    The classical and elementary results for canonical phase space, the Liouville theorem and the beam emittance are reviewed. Then, the importance of phase portraits to obtain a geometrical description of motion is emphasized, with examples in accelerator physics. Finally, a statistical point of view is used to define beam emittance, to study its law of approximate conservation, with three particular examples, and to introduce a beam envelope-ellipse and the β-function, emphasing the statistical features of its properties. (author) 14 refs.; 11 figs

  6. Combustion powered thermophotovoltaic emitter system

    Energy Technology Data Exchange (ETDEWEB)

    McHenry, R.S. [Naval Academy, Annapolis, MD (United States). Naval Architecture, Ocean and Marine Engineering

    1995-07-01

    The US Naval Academy (USNA) has recently completed an engineering design project for a high temperature thermophotovoltaic (TPV) photon emitter. The final apparatus was to be portable, completely self contained, and was to incorporate cycle efficiency optimization such as exhaust stream recuperation. Through computer modeling and prototype experimentation, a methane fueled emitter system was designed from structural ceramic materials to fulfill the high temperature requirements necessary for high system efficiency. This paper outlines the engineering design process, discusses obstacles and solutions encountered, and presents the final design.

  7. Application of avalanche photodiodes for the measurement of actinides by alpha liquid scintillation counting

    International Nuclear Information System (INIS)

    Reboli, A.

    2005-10-01

    Alpha emitters analysis using liquid scintillation spectroscopy is often used when sensitivity and fast samples preparation are the important points. A more extensive use of this technique is until now limited by its poor resolution compared to alpha particle spectroscopy with semiconductor detectors. To improve the resolution and thus promote this method for the measurement of actinides in environment, we have tested silicon avalanche photodiodes (APD) as new detectors for scintillation photons. The set-up consists of a large area avalanche photodiode (16 mm diameter) coupled to a thin vial containing alpha-emitters within a liquid scintillation cocktail. After optimization of several parameters like bias voltage, temperature, counting geometry and composition of the scintillating cocktail, energy resolutions have been found to be better than those obtained with standard photomultiplier tubes (PMT): 5% (200 keV FWHM) for 232 Th and 4.2% (240 keV FWHM) for 236 Pu. Our results show that the improvement is due to less fluctuations associated with light collection since the spatial response of APDs is more uniform than that of PMTs. The expected gain on quantum efficiency (80% for APDs instead of 25% for PMTs) is nullified by a corresponding increase on electronic noise and excess noise factor. Significant better results are foreseen by using green scintillators (450 - 550 nm wavelengths region) with larger Stokes-shift and blue-enhanced APDs which reach their maximum quantum efficiency in this region. (author)

  8. An easy method for the determination of Ra isotopes and actinide alpha emitters from the same water sample

    International Nuclear Information System (INIS)

    Moron, M.C.; Garcia-Tenorio, R.; Garcia-Montano, E.; Garcia-Leon, M.; Madurga, G.

    1986-01-01

    Radium isotopes and actinide α emitters are easily determined from the same water sample. The Ra fraction is obtained by coprecipitation with Ba, while a Fe coprecipitation is used for the actinides. Both fractions are measured with a gas-flow proportional counter. Additionally the isotopic Ra composition is obtained by measuring at two or three different times the α activity from the Ra-fraction. The method is applied to rain water and drinking water samples. (author)

  9. Coupling single emitters to quantum plasmonic circuits

    DEFF Research Database (Denmark)

    Huck, Alexander; Andersen, Ulrik Lund

    2016-01-01

    In recent years, the controlled coupling of single-photon emitters to propagating surface plasmons has been intensely studied, which is fueled by the prospect of a giant photonic nonlinearity on a nanoscaled platform. In this article, we will review the recent progress on coupling single emitters...

  10. Theory and measurements of emittance preservation in plasma wakefield acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Frederico, Joel

    2016-12-01

    In this dissertation, we examine the preservation and measurement of emittance in the plasma wakefield acceleration blowout regime. Plasma wakefield acceleration (PWFA) is a revolutionary approach to accelerating charged particles that has been demonstrated to have the potential for gradients orders of magnitude greater than traditional approaches. The application of PWFA to the design of a linear collider will make new high energy physics research possible, but the design parameters must first be shown to be competitive with traditional methods. Emittance preservation is necessary in the design of a linear collider in order to maximize luminosity. We examine the conditions necessary for circular symmetry in the PWFA blowout regime, and demonstrate that current proposals meet these bounds. We also present an application of beam lamentation which describes the process of beam parameter and emittance matching. We show that the emittance growth saturates as a consequence of energy spread in the beam. The initial beam parameters determine the amount of emittance growth, while the contribution of energy spread is negligible. We also present a model for ion motion in the presence of a beam that is much more dense than the plasma. By combining the model of ion motion and emittance growth, we find the emittance growth due to ion motion is minimal in the case of marginal ion motion. In addition, we present a simulation that validates the ion motion model, which is under further development to examine emittance growth of both marginal and pronounced ion motion. Finally, we present a proof-of-concept of an emittance measurement which may enable the analysis of emittance preservation in future PWFA experiments.

  11. Measurement of transverse emittance in the Fermilab booster

    Energy Technology Data Exchange (ETDEWEB)

    Graves, William Sproull [Wisconsin U., Madison

    1994-01-01

    A new beam profile monitor has been built and installed in the Fermilab Booster synchrotron. It nondestructively measures the beam's vertical density distribution on a fast turn-by-turn basis. This enables one to measure the beam's transverse emittance and to observe emittance growth as it occurs. For high intensities (>2 times 10^{12 } protons), the normalized 95% emittance was observed to grow from 6pi mm-mrad at injection to 16pi mm-mrad at extraction. The initial (<5 msec) emittance growth and beam losses are shown to be caused by the space charge tune shift onto integer and 1/2 integer resonance lines. The growth near injection accounts for approximately 40% of the observed emittance increase throughout the acceleration cycle. The remaining 60% is due to two factors: slow linear growth due to betatron-motion driven by noise in the rf system; and faster growth after the transition energy that is caused by coupling of the longitudinal beam motion into the transverse planes.

  12. Development of gas ionization chambers with coplanar electrodes for alpha-ray spectrometry

    International Nuclear Information System (INIS)

    Iwasaki, Kenta; Tanaka, Naomichi; Murakami, Kohei; Hasebe, Nobuyuki; Kusano, Hiroki; Shibamura, Eido; Miyajima, Mitsuhiro

    2016-01-01

    A large-area alpha-ray spectrometer is required to measure the low level alpha emitters in environmental samples, which may be distributed in the vicinity of nuclear power plants. A gas ionization chamber with a coplanar electrode has attractive features such as with mechanical ruggedness, easy handling, easy fabrication of large electrode, and relatively well-known performance. We have investigated the performance of a gas ionization chamber with a coplanar electrode for alpha-ray spectrometry, particularly in the energy resolution. The present experiment shows that the energy resolution in the full width at half maximum (FWHM) is 129 keV (= 2.7%) for alpha-rays from Np with an energy of 4.78 MeV, 120 keV (= 2.2%) for those with 5.49 MeV from Am, and 109 keV (= 1.9%) for those with 5.81 MeV from Cm. It is found that the energy resolution obtained at the present experiment is dominated in the electronic noise caused by the large capacitance existed between the collecting anode (CA) and non-collecting anode (NCA) in the coplanar electrode. (author)

  13. Some rules to improve the energy resolution in alpha liquid scintillation with beta rejection

    CERN Document Server

    Aupiais, J; Dacheux, N

    2003-01-01

    Two common scintillating mixtures dedicated to alpha measurements by means of alpha liquid scintillation with pulse shape discrimination were tested: the di-isopropylnaphthalene - based and the toluene-based solvents containing the commercial cocktails Ultima Gold AB trademark and Alphaex trademark. We show the possibility to enhance the resolution up to 200% by using no-water miscible cocktails and by reducing the optical path. Under these conditions, the resolution of about 200 keV can be obtained either by the Tri Carb sup T sup M or by the Perals sup T sup M spectrometers. The time responses, e.g., the time required for a complete energy transfer between the initial interaction alpha particle-solvent and the final fluorescence of the organic scintillator, have been compared. Both cocktails present similar behavior. According to the Foerster theory, about 6-10 ns are required to complete the energy transfer. For both apparatus, the detection limits were determined for alpha emitters. The sensitivity of the...

  14. Electromagnetic compatibility of implantable neurostimulators to RFID emitters.

    Science.gov (United States)

    Pantchenko, Oxana S; Seidman, Seth J; Guag, Joshua W; Witters, Donald M; Sponberg, Curt L

    2011-06-09

    The objective of this study is to investigate electromagnetic compatibility (EMC) of implantable neurostimulators with the emissions from radio frequency identification (RFID) emitters. Six active implantable neurostimulators with lead systems were tested for susceptibility to electromagnetic fields generated by 22 RFID emitters. These medical devices have been approved for marketing in the U.S. for a number of intended uses that include: epilepsy, depression, incontinence, Parkinsonian tremor and pain relief. Each RFID emitter had one of the following carrier frequencies: 125 kHz, 134 kHz, 13.56 MHz, 433 MHz, 915 MHz and 2.45 GHz. The test results showed the output of one of the implantable neurostimulators was inhibited by 134 kHz RFID emitter at separation distances of 10 cm or less. The output of the same implantable neurostimulator was also inhibited by another 134 kHz RFID emitter at separation distances of 10 cm or less and also showed inconsistent pulsing rate at a separation distance of 15 cm. Both effects occurred during and lasted through out the duration of the exposure. The clinical significance of the effects was assessed by a clinician at the U.S. Food and Drug Administration. The effects were determined to be clinically significant only if they occurred for extended period of time. There were no observed effects from the other 5 implantable neurostimulators or during exposures from other RFID emitters.

  15. Spherical proton emitters

    International Nuclear Information System (INIS)

    Berg, S.; Semmes, P.B.; Nazarewicz, W.

    1997-01-01

    Various theoretical approaches to proton emission from spherical nuclei are investigated, and it is found that all the methods employed give very similar results. The calculated decay widths are found to be qualitatively insensitive to the parameters of the proton-nucleus potential, i.e., changing the potential parameters over a fairly large range typically changes the decay width by no more than a factor of ∼3. Proton half-lives of observed heavy proton emitters are, in general, well reproduced by spherical calculations with the spectroscopic factors calculated in the independent quasiparticle approximation. The quantitative agreement with experimental data obtained in our study requires that the parameters of the proton-nucleus potential be chosen carefully. It also suggests that deformed proton emitters will provide invaluable spectroscopic information on the angular momentum decomposition of single-proton orbitals in deformed nuclei. copyright 1997 The American Physical Society

  16. Self-powered detectors with thulium emitter

    International Nuclear Information System (INIS)

    Haller, P.; Klar, E.

    1978-01-01

    In addition to fission chambers, prompt-indicating self-powered (SPN) detectors are used for measuring the neutron flux density in the core of power reactors. Although current SPN detectors with a cobalt emitter give satisfactora results, detectors with other emitter materials have been analyzed and tested. The author describes the properties and decay pattern of the nuclide thulium and presents the results of measurements made while testing thulium detectors. (orig.) [de

  17. Innovative energy efficient low-voltage electron beam emitters

    International Nuclear Information System (INIS)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-01-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates

  18. Innovative energy efficient low-voltage electron beam emitters

    Science.gov (United States)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-03-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates.

  19. Antihydrogen detection in ALPHA

    Energy Technology Data Exchange (ETDEWEB)

    Hydomako, Richard, E-mail: rhydomako@phas.ucalgary.ca [University of Calgary, Department of Physics and Astronomy (Canada); Bruun Andresen, Gorm [Aarhus University, Department of Physics and Astronomy (Denmark); Ashkezari, Mohammad Dehghani [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, Marcelo [University of California, Department of Physics (United States); Bertsche, William [Swansea University, Department of Physics (United Kingdom); Butler, Eoin [CERN, European Laboratory for Particle Physics (Switzerland); Bowe, Paul David [Aarhus University, Department of Physics and Astronomy (Denmark); Cesar, Claudo Lenz [Universidade Federal do Rio de Janeiro, Instituto de Fsica (Brazil); Chapman, Steve [University of California, Department of Physics (United States); Charlton, Michael [Swansea University, Department of Physics (United Kingdom); Fajans, Joel [University of California, Department of Physics (United States); Friesen, Tim; Fujiwara, Makoto C. [University of Calgary, Department of Physics and Astronomy (Canada); Gill, David Russell [TRIUMF (Canada); Hangst, Jeffrey Scott [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, Walter Newbold [University of British Columbia, Department of Physics and Astronomy (Canada); Hayano, Ryugo S. [University of Tokyo, Department of Physics (Japan); Hayden, Michael Edward [Simon Fraser University, Department of Physics (Canada); Humphries, Andrew James [Swansea University, Department of Physics (United Kingdom); Jonsell, Svante [Stockholm University, Fysikum (Sweden); Collaboration: ALPHA Collaboration; and others

    2012-12-15

    The ALPHA project is an international collaboration, based at CERN, with the experimental goal of performing precision spectroscopic measurements on antihydrogen. As part of this endeavor, the ALPHA experiment includes a silicon tracking detector. This detector consists of a three-layer array of silicon modules surrounding the antihydrogen trapping region of the ALPHA apparatus. Using this device, the antihydrogen annihilation position can be determined with a spatial resolution of better than 5 mm. Knowledge of the annihilation distribution was a critical component in the recently successful antihydrogen trapping effort. This paper will describe the methods used to reconstruct annihilation events in the ALPHA detector. Particular attention will be given to the description of the background rejection criteria.

  20. Induction of cancers in the rat after inhalation of alpha-emitting radionuclides

    International Nuclear Information System (INIS)

    Morin, M.; Nenot, J.C.; Masse, R.; Nolibe, D.; Metivier, H.; Lafuma, J.

    1976-01-01

    Experiments have been conducted for several years on the toxic action of inhaled alpha-emitters on laboratory rats. The inhaled radionuclides were 239 Pu, 238 Pu and 241 Am in oxide and nitrate form. The initial alveolar activities varied to give total activities ranging from 1 to 200 thousand million alpha-particles per gram of lung. Variations, depending on the physico-chemical form of the nuclides, in the space and time distributions of the dose are observed. The influence of the two parameters on life span reduction, latency time and frequency of cancer occurrence, initial location of tumours and their histological types were studied. A theoretical model relating the cancerogenous effect to the dose is compared with experimental data. (author)

  1. Evaluations of carbon nanotube field emitters for electron microscopy

    Science.gov (United States)

    Nakahara, Hitoshi; Kusano, Yoshikazu; Kono, Takumi; Saito, Yahachi

    2009-11-01

    Brightness of carbon nanotube (CNT) emitters was already reported elsewhere. However, brightness of electron emitter is affected by a virtual source size of the emitter, which strongly depends on electron optical configuration around the emitter. In this work, I- V characteristics and brightness of a CNT emitter are measured under a practical field emission electron gun (e-gun) configuration to investigate availability of CNT for electron microscopy. As a result, it is obtained that an emission area of MWNT is smaller than its tip surface area, and the emission area corresponds to a five-membered-ring with 2nd nearest six-membered-rings on the MWNT cap surface. Reduced brightness of MWNT is measured as at least 2.6×109 A/m 2 sr V. It is concluded that even a thick MWNT has enough brightness under a practical e-gun electrode configuration and suitable for electron microscopy.

  2. Very bright, near-infrared single photon emitters in diamond

    Directory of Open Access Journals (Sweden)

    D. W. M. Lau

    2013-09-01

    Full Text Available We demonstrate activation of bright diamond single photon emitters in the near infrared range by thermal annealing alone, i.e., without ion implantation. The activation is crucially dependent on the annealing ambient. The activation of the single photon emitters is only observed when the sample is annealed in forming gas (4% H2 in Ar above temperatures of 1000 °C. By contrast, no emitters are activated by annealing in vacuum, oxygen, argon or deuterium. The emitters activated by annealing in forming gas exhibit very bright emission in the 730-760 nm wavelength range and have linewidths of ∼1.5-2.5 nm at room temperature.

  3. Measurement of emittance of metal interface in molten salt

    International Nuclear Information System (INIS)

    Araki, N.; Makino, A.; Nakamura, Y.

    1995-01-01

    A new technique for measuring the total normal emittance of a metal in a semi-transparent liquid has been proposed and this technique has been applied to measure the emittance of stainless steel (SUS304), nickel, and gold in molten potassium nitrate KNO 3 . These emittance data are indispensable to analyzing the radiative heat transfer between a metal and a semitransparent liquid, such as a molten salt

  4. Boundary conditions on the plasma emitter surface in the presence of a particle counter flow: I. Ion emitter

    Energy Technology Data Exchange (ETDEWEB)

    Astrelin, V. T., E-mail: V.T.Astrelin@inp.nsk.su; Kotelnikov, I. A. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)

    2017-02-15

    Emission of positively charged ions from a plasma emitter irradiated by a counterpropagating electron beam is studied theoretically. A bipolar diode with a plasma emitter in which the ion temperature is lower than the electron temperature and the counter electron flow is extracted from the ion collector is calculated in the one-dimensional model. An analog of Bohm’s criterion for ion emission in the presence of a counterpropagating electron beam is derived. The limiting density of the counterpropagating beam in a bipolar diode operating in the space-charge-limited-emission regime is calculated. The full set of boundary conditions on the plasma emitter surface that are required for operation of the high-current optics module in numerical codes used to simulate charged particle sources is formulated.

  5. Electromagnetic compatibility of implantable neurostimulators to RFID emitters

    Directory of Open Access Journals (Sweden)

    Guag Joshua W

    2011-06-01

    Full Text Available Abstract Background The objective of this study is to investigate electromagnetic compatibility (EMC of implantable neurostimulators with the emissions from radio frequency identification (RFID emitters. Methods Six active implantable neurostimulators with lead systems were tested for susceptibility to electromagnetic fields generated by 22 RFID emitters. These medical devices have been approved for marketing in the U.S. for a number of intended uses that include: epilepsy, depression, incontinence, Parkinsonian tremor and pain relief. Each RFID emitter had one of the following carrier frequencies: 125 kHz, 134 kHz, 13.56 MHz, 433 MHz, 915 MHz and 2.45 GHz Results The test results showed the output of one of the implantable neurostimulators was inhibited by 134 kHz RFID emitter at separation distances of 10 cm or less. The output of the same implantable neurostimulator was also inhibited by another 134 kHz RFID emitter at separation distances of 10 cm or less and also showed inconsistent pulsing rate at a separation distance of 15 cm. Both effects occurred during and lasted through out the duration of the exposure. Conclusions The clinical significance of the effects was assessed by a clinician at the U.S. Food and Drug Administration. The effects were determined to be clinically significant only if they occurred for extended period of time. There were no observed effects from the other 5 implantable neurostimulators or during exposures from other RFID emitters.

  6. Emittance growth and tune spectra at PETRA III

    International Nuclear Information System (INIS)

    Wanzenberg, R.

    2011-08-01

    At DESY the PETRA ring has been converted into a synchrotron radiation facility, called PETRA III. 20 damping wigglers have been installed to achieve an emittance of 1 nm. The commissioning with beam started in April 2009 and user runs have been started in 2010. The design current is 100 mA and the bunch to bunch distance is 8 ns for one particular filling pattern with 960 bunches. At a current of about 50 mA a strong vertical emittance increase has been observed. During machine studies it was found that the emittance increase depends strongly on the bunch filling pattern. For the user operation a filling scheme has been found which mitigates the increase of the vertical emittance. In August 2010 PETRA III has been operated without damping wigglers for one week. The vertical emittance growth was not significantly smaller without wigglers. Furthermore tune spectra at PETRA III show characteristic lines which have been observed at other storage rings in the connection with electron clouds. Measurements at PETRA III are presented for different bunch filling patterns and with and without wiggler magnets. (orig.)

  7. Alpha self-irradiation effects in ternary oxides of actinides elements: The zircon-like phases AmIIIVO4 and AIINpIV(VO4)2 (A=Sr, Pb)

    International Nuclear Information System (INIS)

    Goubard, F.; Griesmar, P.; Tabuteau, A.

    2005-01-01

    We report the experimental studies of irradiation damage from alpha decay in neptunium and americium vanadates versus cumulative dose. The isotopes used were the transuranium α-emitter 237 Np and the α,γ-emitter 241 Am. Neptunium and americium vanadates self-irradiation was studied by X-ray diffraction method (XRD). The comparison of the powder diffraction patterns reveal that the irradiation has no apparent effect on the neptunium phases while the americium vanadate swells and becomes metamict as a function of cumulative dose

  8. A polarization-insensitive plasmonic photoconductive terahertz emitter

    KAUST Repository

    Li, Xurong

    2017-11-16

    We present a polarization-insensitive plasmonic photoconductive terahertz emitter that uses a two-dimensional array of nanoscale cross-shaped apertures as the plasmonic contact electrodes. The geometry of the cross-shaped apertures is set to maximize optical pump absorption in close proximity to the contact electrodes. The two-dimensional symmetry of the cross-shaped apertures offers a polarization-insensitive interaction between the plasmonic contact electrodes and optical pump beam. We experimentally demonstrate a polarization-insensitive terahertz radiation from the presented emitter in response to a femtosecond optical pump beam and similar terahertz radiation powers compared to previously demonstrated polarization-sensitive photoconductive emitters with plasmonic contact electrode gratings at the optimum optical pump polarization.

  9. Emittance measurement for high-brightness electron guns

    International Nuclear Information System (INIS)

    Kobayashi, H.; Kurihara, T.; Sato, I.; Asami, A.; Yamazaki, Y.; Otani, S.; Ishizawa, Y.

    1992-01-01

    An emittance measurement system based on a high-precision pepper-pot technique has been developed for electron guns with low emittance of around πmm-mrad. Electron guns with a 1 mmφ cathode, the material of which is impregnated tungsten or single-crystal lanthanum hexaboride (La 1-x Ce x )B 6 , have been developed. The performance has been evaluated by putting stress on cathode roughness, which gives rise to an angular divergence, according to the precise emittance measurement system. A new type of cathode holder, which is a modified version of the so called Vogel type, was developed and the beam uniformity has been improved. (Author) 5 figs., tab., 9 refs

  10. Determination of alpha activity produced by Indian tea samples using solid state nuclear track detection technique

    International Nuclear Information System (INIS)

    Azam, Ameer; Naqvi, A.H.; Srivastava, D.S.

    2001-01-01

    India has first place in the world in the production, consumption and export of tea. The average production of tea in India is about 780 million kg annually. Indian population uses tea as a favourite beverage specially with the breakfast. Tea leaves are perennial plants and they have extension root system spread over deeper layers in the soil. Soil contains uranium as trace element. Hence, uranium is transferred to the leaves as a result of uptake from the soil over the years. Since many of the decay products of uranium are alpha emitters hence tea is a source of alpha radioactivity and can cause damaging effects. Therefore, data on alpha activity of tea samples will be useful in estimating these harmful effects at least qualitatively. In the present study the alpha activity produced by thirteen samples of tea available in the local market was measured

  11. Evaluations of carbon nanotube field emitters for electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, Hitoshi, E-mail: nakahara@nagoya-u.jp [Department of Quantum Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kusano, Yoshikazu; Kono, Takumi; Saito, Yahachi [Department of Quantum Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2009-11-30

    Brightness of carbon nanotube (CNT) emitters was already reported elsewhere. However, brightness of electron emitter is affected by a virtual source size of the emitter, which strongly depends on electron optical configuration around the emitter. In this work, I-V characteristics and brightness of a CNT emitter are measured under a practical field emission electron gun (e-gun) configuration to investigate availability of CNT for electron microscopy. As a result, it is obtained that an emission area of MWNT is smaller than its tip surface area, and the emission area corresponds to a five-membered-ring with 2nd nearest six-membered-rings on the MWNT cap surface. Reduced brightness of MWNT is measured as at least 2.6x10{sup 9} A/m{sup 2} sr V. It is concluded that even a thick MWNT has enough brightness under a practical e-gun electrode configuration and suitable for electron microscopy.

  12. Few emitters in a cavity: from cooperative emission to individualization

    International Nuclear Information System (INIS)

    Auffeves, A; Portolan, S; Gerace, D; Drezet, A; Franca Santos, M

    2011-01-01

    We study the temporal correlations of the field emitted by an electromagnetic resonator coupled to a mesoscopic number of two-level emitters that are incoherently pumped by a weak external drive. We solve the master equation of the system for increasing number of emitters and as a function of the cavity quality factor, and we identify three main regimes characterized by well-distinguished statistical properties of the emitted radiation. For small cavity decay rates, the emission events are uncorrelated and the number of photons in the emitted field becomes larger than one, resembling the build-up of a laser field inside the cavity. At intermediate decay rates (as compared with the emitter-cavity coupling) and for a few emitters, the statistics of the emitted radiation is bunched and strikingly dependent on the parity of the number of emitters. The latter property is related to the cooperativity of the emitters mediated by their coupling to the cavity mode, and its connection with steady-state subradiance is discussed. Finally, in the bad cavity regime the typical situation of emission from a collection of individual emitters is recovered. We also analyze how the cooperative behavior evolves as a function of pure dephasing, which allows us to recover the case of a classical source made of an ensemble of independent emitters, similar to what is obtained for a very leaky cavity. State-of-the-art techniques of Q-switch of resonant cavities, allied with the recent capability of tuning single emitters in and out of resonance, suggest this system to be a versatile source of different quantum states of light.

  13. Few emitters in a cavity: from cooperative emission to individualization

    Energy Technology Data Exchange (ETDEWEB)

    Auffeves, A; Portolan, S [CEA/CNRS/UJF Joint Team ' Nanophysics and Semiconductors' , Institut Neel-CNRS, BP 166, 25 Rue des Martyrs, 38042 Grenoble Cedex 9 (France); Gerace, D [Dipartimento di Fisica ' Alessandro Volta' and UdR CNISM, Universita di Pavia, via Bassi 6, 27100 Pavia (Italy); Drezet, A [Institut Neel-CNRS, BP 166, 25 Rue des Martyrs, 38042 Grenoble Cedex 9 (France); Franca Santos, M, E-mail: msantos@fisica.ufmg.br [Departamento de Fisica, Universidade Federal de Minas Gerais, Belo Horizonte, CP 702, 30123-970 (Brazil)

    2011-09-15

    We study the temporal correlations of the field emitted by an electromagnetic resonator coupled to a mesoscopic number of two-level emitters that are incoherently pumped by a weak external drive. We solve the master equation of the system for increasing number of emitters and as a function of the cavity quality factor, and we identify three main regimes characterized by well-distinguished statistical properties of the emitted radiation. For small cavity decay rates, the emission events are uncorrelated and the number of photons in the emitted field becomes larger than one, resembling the build-up of a laser field inside the cavity. At intermediate decay rates (as compared with the emitter-cavity coupling) and for a few emitters, the statistics of the emitted radiation is bunched and strikingly dependent on the parity of the number of emitters. The latter property is related to the cooperativity of the emitters mediated by their coupling to the cavity mode, and its connection with steady-state subradiance is discussed. Finally, in the bad cavity regime the typical situation of emission from a collection of individual emitters is recovered. We also analyze how the cooperative behavior evolves as a function of pure dephasing, which allows us to recover the case of a classical source made of an ensemble of independent emitters, similar to what is obtained for a very leaky cavity. State-of-the-art techniques of Q-switch of resonant cavities, allied with the recent capability of tuning single emitters in and out of resonance, suggest this system to be a versatile source of different quantum states of light.

  14. Emittance formula for slits and pepper-pot measurement

    International Nuclear Information System (INIS)

    Zhang, M.

    1996-10-01

    In this note, a rigid formula for slits and pepper-pot emittance measurement is derived. The derivation is based on the one- dimensional slit measurement setup. A mathematical generalization of the slit emittance formula to the pepper-pot measurement is discussed

  15. MEV Energy Electrostatic Accelerator Ion Beam Emittance Measurement

    OpenAIRE

    I.G. Ignat’ev; M.I. Zakharets; S.V. Kolinko; D.P. Shulha

    2014-01-01

    The testing equipment was designed, manufactured and tried out permitting measurements of total current, current profile and emittance of an ion beam extracted from the ion beam. MeV energy electrostatic accelerator ion H + beam emittance measurement results are presented.

  16. Relative biological effectiveness of alpha-particle emitters in vivo at low doses

    International Nuclear Information System (INIS)

    Howell, R.W.; Azure, M.T.; Narra, V.R.; Rao, D.V.

    1994-01-01

    The therapeutic potential of radionuclides that emit α particles, as well as their associated health hazards, have attracted considerable attention. The 224 Ra daughters 212 Pb and 212 Bi, by virtue of their radiation properties which involve emission of α and β particles in their decay to stable 208 Pb, have been proposed as candidates for radioimmunotherapy. Using mouse testes as the experimental model and testicular spermhead survival as the biological end point, the present work examines the radiotoxicity of 212 Pb and its daughters. When 212 Pb, in equilibrium with its daughters 212 Bi, 212 Po and 208 Tl, was administered directly into the testis, the dose required to achieve 37% survival (D 37 ) was 0.143 ± 0.014 Gy and the corresponding RBE of the mixed radiation field was 4.7 when compared to the D 37 for acute external 120 kVp X rays. This datum, in conjunction with our earlier results for 210 Po, was used to obtain an RBE-LET relationship for α particles emitted by tissue-incorporated radionuclides: RBE α = 4.8 - 6.1 x 10 -2 LET + 1.0 x 10 -3 LET 2 . Similarly, the dependence of RBE on α-particle energy E α was given by RBE α = 22 E α -0.73 . These relationships, based on in vivo experimental data, may be valuable in predicting biological effects of α-particle emitters. 46 refs., 6 figs

  17. A survey of the alpha-nucleon interaction

    International Nuclear Information System (INIS)

    Ali, S.; Ahmad, A.A.Z.; Ferdous, N.

    1984-10-01

    A survey of the alpha-nucleon interaction is made. The experimental work on angular distributions of differential scattering cross-sections and polarizations in proton-alpha and neutron-alpha scattering is described. The phenomenological approach which includes the study of both local and non-local potentials reproducing the experimental alpha-nucleon scattering data, is discussed. Basic studies of the alpha-nucleon interaction attempting to build an interaction between an alpha particle and a nucleon from first principles are then described. A critical discussion of the results with some concluding remarks suggesting the direction for further investigation is made. (author)

  18. Experimental investigation of thermal emittance components of copper photocathode

    Directory of Open Access Journals (Sweden)

    H. J. Qian

    2012-04-01

    Full Text Available With progress of photoinjector technology, thermal emittance has become the primary limitation of electron beam brightness. Extensive efforts have been devoted to study thermal emittance, but experiment results differ between research groups and few can be well interpreted. Besides the ambiguity of photoemission mechanism, variations of cathode surface conditions during cathode preparation, such as work function, field enhancement factor, and surface roughness, will cause thermal emittance differences. In this paper, we report an experimental study of electric field dependence of copper cathode quantum efficiency (QE and thermal emittance in a radio frequency (rf gun, through which in situ cathode surface parameters and thermal emittance contributions from photon energy, Schottky effect, and surface roughness are extracted. It is found the QE of a copper cathode illuminated by a 266 nm UV laser increased substantially to 1.5×10^{-4} after cathode cleaning during rf conditioning, and a copper work function of 4.16 eV, which is much lower than nominal value (4.65 eV, was measured. Experimental results also show a thermal emittance growth as much as 0.92  mm mrad/mm at 50  MV/m due to the cathode surface roughness effect, which is consistent with cathode surface morphology measurements.

  19. Design for a practical, low-emittance damping ring

    International Nuclear Information System (INIS)

    Krejcik, P.

    1988-01-01

    The luminosity requirements for future high-energy linear colliders calls for very low emittances in the two beams. These low emittances can be achieved with damping rings, but, in order to reach the design goal of a factor 10 improvement over present day machines, great care must be taken in their design. This paper emphasizes the need to address simultaneously all of the factors which limit the operational emittance in the ring. Particularly since in standard designs there is a conflict between different design parameters which makes it difficult to extrapolate such designs to very low emittances. The approach chosen here is to resolve such conflicts by separating their design solutions. Wigglers are used predominantly in zero-dispersion regions to achieve the desired damping rate, whereas in the arcs high dispersion insertions are made in regions of zero curvature to allow for easier chromaticity control

  20. (Alpha-) quenching temperature dependence in liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Arnd; Lozza, Valentina; Krosigk, Belina von; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, TU Dresden (Germany)

    2015-07-01

    Liquid scintillator (LS) is an effective and promising detector material, which is and will be used by many small and large scale experiments. In order to perform correct signal identification and background suppression, a very good knowledge of LS properties is crucial. One of those is the light yield from alpha particles in liquid scintillator. This light output strongly quenched, approx. 10 times compared to that of electrons, and has been precisely studied at room temperature for various LS. Big scintillator experiments, such as SNO+ and maybe future large scale detectors, will operate at different temperatures. While a strong temperature dependence is well known for solid state scintillators, due to the different scintillation process, a quenching temperature dependence in LS is usually assumed negligible. On the other hand, inconsistencies in between measurements are often explained by potential temperature effects. This study investigates LAB based liquid scintillator with an intrinsic, dissolved alpha emitter and its behaviour with temperature change. In a small, cooled and heated setup, a stabilized read-out with two PMTs is realised. First results are presented.

  1. High-LET alpha-emitters: Radon, lung cancer and smoking

    International Nuclear Information System (INIS)

    Fabrikant, J.I.

    1988-11-01

    The National Academy of Sciences BEIR IV Report deals with the health effects in human populations exposed to internally-deposited alpha-emitting radionuclides and their decay products. Quantitative risk estimates for cancer induction are derived, mainly from analyses of epidemiological data. The Report addresses the health outcomes of exposure to radon and its daughters, primarily lung cancer risks of worker exposure to radon progeny in underground mines and in the general public in indoor domestic environments. An excess relative risk model of lung cancer mortality and exposure to radon progeny is developed; this models the excess risk per Working Level Month in terms of time intervals prior to an attained age, and is dependent on time-since-exposure and age at risk. Risk projections are presented and cover exposure situations of current public health concern. For example, lifetime exposure to 1 WLM y/sup /minus/1/ is estimated to increase the number of deaths due to lung cancer by a factor of about 1.5 over the current rate for both males and females in a population having the current prevalence of cigarette-smoking. Occupational exposure to 4 WLM y/sup /minus/1/ from ages 20 y to 40 y is projected to increase lung cancer deaths by a factor of 1.6 over the current rate of this age cohort in the general population. In all of these cases, most of the increased risk occurs to smokers for whom the risk is up to ten times greater than for non-smokers. 8 refs., 1 tab

  2. Test results of the signal processing and amplifier unit for the emittance measurement system

    International Nuclear Information System (INIS)

    Stawiszynski, L.; Schneider, S.

    1984-01-01

    The signal processing and amplifier unit for the emittance measurement system is the unit with which the beam current on the harp-wires and the slit is measured and converted to a digital output. Temperature effects are very critical at low currents and the purpose of the test measurements described in this report was mainly to establish the accuracy and repeatability of the measurements under the influence of temperature variations

  3. Design of a minimum emittance nBA lattice

    Science.gov (United States)

    Lee, S. Y.

    1998-04-01

    An attempt to design a minimum emittance n-bend achromat (nBA) lattice has been made. One distinct feature is that dipoles with two different lengths were used. As a multiple bend achromat, five bend achromat lattices with six superperiod were designed. The obtained emittace is three times larger than the theoretical minimum. Tunes were chosen to avoid third order resonances. In order to correct first and second order chromaticities, eight family sextupoles were placed. The obtained emittance of five bend achromat lattices is almost equal to the minimum emittance of five bend achromat lattice consisting of dipoles with equal length.

  4. Remote detection of single emitters via optical waveguides

    Science.gov (United States)

    Then, Patrick; Razinskas, Gary; Feichtner, Thorsten; Haas, Philippe; Wild, Andreas; Bellini, Nicola; Osellame, Roberto; Cerullo, Giulio; Hecht, Bert

    2014-05-01

    The integration of lab-on-a-chip technologies with single-molecule detection techniques may enable new applications in analytical chemistry, biotechnology, and medicine. We describe a method based on the reciprocity theorem of electromagnetic theory to determine and optimize the detection efficiency of photons emitted by single quantum emitters through truncated dielectric waveguides of arbitrary shape positioned in their proximity. We demonstrate experimentally that detection of single quantum emitters via such waveguides is possible, confirming the predicted behavior of the detection efficiency. Our findings blaze the trail towards efficient lensless single-emitter detection compatible with large-scale optofluidic integration.

  5. Movement of Irrigation Water in Soil from a Surface Emitter

    Directory of Open Access Journals (Sweden)

    Ibrahim Abbas Dawood

    2016-09-01

    Full Text Available rickle irrigation is one of the most conservative irrigation techniques since it implies supplying water directly on the soil through emitters. Emitters dissipate energy of water at the end of the trickle irrigation system and provide water at emission points. The area wetted by an emitter depends upon the discharge of emitter, soil texture, initial soil water content, and soil permeability. The objectives of this research were to predict water distribution profiles through different soils for different conditions and quantify the distribution profiles in terms of main characteristics of soil and emitter. The wetting patterns were simulated at the end of each hour for a total time of application of 12 hrs, emitter discharges of 0.5, 0.75, 1, 2, 3, 4, and 5 lph, and five initial volumetric soil water contents. Simulation of water flow from a single surface emitter was carried out by using the numerically-based software Hydrus-2D/3D, Version 2.04. Two approaches were used in developing formulas to predict the domains of the wetted pattern. In order to verify the results obtained by implementing the software Hydrus-2D/3D a field experiment was conducted to measure the wetted diameter and compare measured values with simulated ones. The results of the research showed that the developed formulas to express the wetted diameter and depth in terms of emitter discharge, time of application, and initial soil water content are very general and can be used with very good accuracy.

  6. 49 CFR 173.403 - Definitions.

    Science.gov (United States)

    2010-10-01

    ... emitters and low toxicity alpha emitters or 0.04 Bq/cm2 for all other alpha emitters. Contamination exists... containers.” Graphite means, for the purposes of § 173.453, graphite with a boron equivalent content less... A2/g. Low toxicity alpha emitters means natural uranium; depleted uranium; natural thorium; uranium...

  7. Jamming of Quantum Emitters by Active Coated Nanoparticles

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Ziolkowski, Richard W.

    2013-01-01

    to effectively cloak the emitters to a far-field observer is reported and explained through thorough near- and far-field investigations. This property offers an interesting route toward the jamming of quantum emitters/nanoantennas that might be of potential use, for instance, in biological fluorescence assays...

  8. Transverse Emittance Measurement and Preservation at the LHC

    CERN Document Server

    AUTHOR|(CDS)2082907

    The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle physics. The luminosity production is closely linked to emittance preservation in the accelerator. The transverse emittance is the phase space density of the beam and should be conserved when the particle beam is transformed through the accelerator. Perturbing effects, however, can lead to emittance increase and hence luminosity degradation. Measuring the emittance growth is a complex task with high intensity beams and changing energies. The machine optics and the transverse beam size have to be measured as accurately as possible. Beta function measurements with k-modulation will be discussed. With this method the quadrupole focussing strength is varied and the resulting tune change is traced to determine the beta function at the quadrupole. A new k-modulation measurement tool was developed for the LHC. The fully automatic and online measurement system takes constra...

  9. Emittance increase caused by core depletion in collisions

    CERN Document Server

    Bruce, R

    2009-01-01

    A new effect is presented, which changes the emittance during colliding-beam operation in circular colliders. If the initial transverse distribution is Gaussian, the collision probability is much higher for particles in the core of the beam than in the tails. When small-amplitude particles are removed, the remaining ones therefore have a larger transverse emittance. This effect, called core depletion, may cause a decrease in luminosity. An approximate analytic model is developed to study the effect and benchmarked against a multiparticle tracking simulation. Finally, the time evolution of the intensity and emittances of a Pb bunch in the Large Hadron Collider (LHC) at CERN is calculated, taking into account also other processes than collisions. The results show that integrated luminosity drops by 3--4% if core depletion is taken into account. It is also found that core depletion causes the transverse emittance to be larger when more experiments are active. This observation could be checked against experimenta...

  10. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

  11. Development of optical monitor of alpha radiations based on CR-39.

    Science.gov (United States)

    Joshirao, Pranav M; Shin, Jae Won; Vyas, Chirag K; Kulkarni, Atul D; Kim, Hojoong; Kim, Taesung; Hong, Seung-Woo; Manchanda, Vijay K

    2013-11-01

    Fukushima accident has highlighted the need to intensify efforts to develop sensitive detectors to monitor the release of alpha emitting radionuclides in the environment caused by the meltdown of the discharged spent fuel. Conventionally, proportional counting, scintillation counting and alpha spectrometry are employed to assay the alpha emitting radionuclides but these techniques are difficult to be configured for online operations. Solid State Nuclear Track Detectors (SSNTDs) offer an alternative off line sensitive technique to measure alpha emitters as well as fissile radionuclides at ultra-trace level in the environment. Recently, our group has reported the first ever attempt to use reflectance based fiber optic sensor (FOS) to quantify the alpha radiations emitted from (232)Th. In the present work, an effort has been made to develop an online FOS to monitor alpha radiations emitted from (241)Am source employing CR-39 as detector. Here, we report the optical response of CR-39 (on exposure to alpha radiations) employing techniques such as Atomic Force Microscopy (AFM) and Reflectance Spectroscopy. In the present work GEANT4 simulation of transport of alpha particles in the detector has also been carried out. Simulation includes validation test wherein the projected ranges of alpha particles in the air, polystyrene and CR-39 were calculated and were found to agree with the literature values. An attempt has been further made to compute the fluence as a function of the incidence angle and incidence energy of alphas. There was an excellent correlation in experimentally observed track density with the simulated fluence. The present work offers a novel approach to design an online CR-39 based fiber optic sensor (CRFOS) to measure the release of nanogram quantity of (241)Am in the environment. © 2013 Elsevier Ltd. All rights reserved.

  12. Radial arrays of nano-electrospray ionization emitters and methods of forming electrosprays

    Science.gov (United States)

    Kelly, Ryan T [West Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

    2010-10-19

    Electrospray ionization emitter arrays, as well as methods for forming electrosprays, are described. The arrays are characterized by a radial configuration of three or more nano-electrospray ionization emitters without an extractor electrode. The methods are characterized by distributing fluid flow of the liquid sample among three or more nano-electrospray ionization emitters, forming an electrospray at outlets of the emitters without utilizing an extractor electrode, and directing the electrosprays into an entrance to a mass spectrometry device. Each of the nano-electrospray ionization emitters can have a discrete channel for fluid flow. The nano-electrospray ionization emitters are circularly arranged such that each is shielded substantially equally from an electrospray-inducing electric field.

  13. The cataphoretic emitter effect exhibited in high intensity discharge lamp electrodes

    Science.gov (United States)

    Mentel, Juergen

    2018-01-01

    A mono-layer of atoms, electropositive with respect to the substrate atoms, forms a dipole layer, reducing its work function. Such a layer is generated by diffusion of emitter material from the interior of the substrate, by vapour deposition or by deposition of emitter material onto arc electrodes by cataphoresis. This cataphoretic emitter effect is investigated within metal halide lamps with transparent YAG ceramic burners, and within model lamps. Within the YAG lamps, arcs are operated with switched-dc current between rod shaped tungsten electrodes in high pressure Hg vapour seeded with metal iodides. Within the model lamps, dc arcs are operated between rod-shaped tungsten electrodes—one doped—in atmospheric pressure Ar. Electrode temperatures are determined by 1λ -pyrometry, combined with simulation of the electrode heat balance. Plasma temperatures, atom and ion densities of emitter material are determined by emission and absorption spectroscopy. Phase resolved measurements in YAG lamps seeded with CeI3, CsI, DyI3, TmI3 and LaI3 show, within the cathodic half period, a reduction of the electrode temperature and an enhanced metal ion density in front of the electrode, and an opposite behavior after phase reversal. With increasing operating frequency, the state of the cathode overlaps onto the anodic phase—except for Cs, being low in adsorption energy. Generally, the phase averaged electrode tip temperature is reduced by seeding a lamp with emitter material; its height depends on admixtures. Measurements at tungsten electrodes doped with ThO2, La2O3 and Ce2O3 within the model lamp show that evaporated emitter material is redeposited by an emitter ion current onto the electrode surface. It reduces the work function of tungsten cathodes above the evaporation temperature of the emitter material, too; and also of cold anodes, indicating a field reversal in front of them. The formation of an emitter spot at low cathode temperature and high emitter material

  14. Repeated Intraperitoneal alpha-Radioimmunotherapy of Ovarian Cancer in Mice

    DEFF Research Database (Denmark)

    Elgqvist, Jörgen; Andersson, Håkan; Jensen, Holger

    2010-01-01

    The aim of this study was to investigate the therapeutic efficacy of alpha-radioimmunotherapy of ovarian cancer in mice using different fractionated treatment regimens. The study was performed using the monoclonal antibody MX35 F(ab')(2) labeled with the alpha-particle emitter (211)At. Methods....... Nude mice were intraperitoneally inoculated with ~1 x 10(7) cells of the cell line NIH:OVCAR-3. Four weeks later 6 groups of animals were given 400 kBq (211)At-MX35 F(ab')(2) as a single or as a repeated treatment of up to 6 times (n = 18 in each group). The fractionated treatments were given every...... seventh day. Control animals were treated with unlabeled MX35 F(ab')(2) (n = 12). Eight weeks posttreatment the animals were sacrificed and the presence of macro- and microscopic tumors and ascites was determined. Results. The tumor-free fractions (TFFs) of the animals, defined as the fraction of animals...

  15. Role of quenching on alpha/beta separation in liquid scintillation counting for several high capacity cocktails

    International Nuclear Information System (INIS)

    Pujol, L.; Sanchez-Cabeza, J.-A.

    1997-01-01

    The optimization of alpha/beta separation in liquid scintillation using pulse shape analysis is convenient for the simultaneous determination of alpha and beta emitters in natural water and other samples. In this work, alpha/beta separation was studied for different scintillant/vial combinations and it was observed that both the optimum pulse shape discrimination level and the total interference value (that is, the summed relative interference between alpha and beta spectra) were dependent on the sample quenching and independent of the scintillant/vial combination. These results provide a simple method for modifying the counting configuration, such as a change in the cocktail, vial or sample characteristics, without the need to perform exhaustive parameter optimizations. Also, it was observed that, for our counting conditions, the combination of Ultima Gold AB scintillation cocktail with Zinsser low diffusion vials presented the lowest total interference, namely 0.94 ± 0.28%, which is insignificant for the counting of environmental samples. (Author)

  16. Low emittance lattices for electron storage rings revisited

    International Nuclear Information System (INIS)

    Trbojevic, D.; Courant, E.

    1994-01-01

    Conditions for the lowest possible emittance of the lattice for electron storage rings are obtained by a simplified analytical approach. Examples of electron storage lattices with minimum emittances are presented. A simple graphical presentation in the normalized dispersion space (Floquet's transformation) is used to illustrate the conditions and results

  17. BEAM EMITTANCE MEASUREMENT TOOL FOR CEBAF OPERATIONS

    International Nuclear Information System (INIS)

    Chevtsov, Pavel; Tiefenback, Michael

    2008-01-01

    A new software tool was created at Jefferson Lab to measure the emittance of the CEBAF electron beams. The tool consists of device control and data analysis applications. The device control application handles the work of wire scanners and writes their measurement results as well as the information about accelerator settings during these measurements into wire scanner data files. The data analysis application reads these files and calculates the beam emittance on the basis of a wire scanner data processing model. Both applications are computer platform independent but are mostly used on LINUX PCs recently installed in the accelerator control room. The new tool significantly simplifies beam emittance measurement procedures for accelerator operations and contributes to a very high availability of the CEBAF machine for the nuclear physics program at Jefferson Lab.

  18. The acute effects of alpha and beta irradiation of mouse skin and the factors affecting the response

    International Nuclear Information System (INIS)

    Needham, S.G.; Coggle, J.E.

    1991-01-01

    Several problems regarding acute effects of alpha and beta irradiation were investigated in order to clarify protection problems of localised doses to the skin. A study into the acute biological effects of different energy beta emitters and the effects of energy and area on the response showed direct relationships between these criteria for a range of different acute responses with different time courses. Three different types of acute response were found and these are described as 'moist desquamation', 'acute ulceration' and 'acute epidermal necrosis'. An unexpected finding was that the lower energy beta emitter 170 Tm was as efficient at inducing scab formation as the higher energy 90 Sr sources for the same area of exposure. Experiments using 2x4 cm 2 exposures to 224 Cm alpha particles showed that the response to this poorly penetrating radiation was minimal after doses as high as 180 Gy measured at 10 μm into the skin. In comparison, large area exposure to 170 Tm produced areas of prolonged scabbing after doses up to 100 Gy. However, the intensity of the reaction varied between strains. (author)

  19. Quantifying, Assessing, and Mitigating Methane Emissions from Super-emitters in the Oil and Gas Supply Chain

    Science.gov (United States)

    Lyon, David Richard

    Methane emissions from the oil and gas (O&G) supply chain reduce potential climate benefits of natural gas as a replacement for other fossil fuels that emit more carbon dioxide per energy produced. O&G facilities have skewed emission rate distributions with a small fraction of sites contributing the majority of emissions. Knowledge of the identity and cause of these high emission facilities, referred to as super-emitters or fat-tail sources, is critical for reducing supply chain emissions. This dissertation addresses the quantification of super-emitter emissions, assessment of their prevalence and relationship to site characteristics, and mitigation with continuous leak detection systems. Chapter 1 summarizes the state of the knowledge of O&G methane emissions. Chapter 2 constructs a spatially-resolved emission inventory to estimate total and O&G methane emissions in the Barnett Shale as part of a coordinated research campaign using multiple top-down and bottom-up methods to quantify emissions. The emission inventory accounts for super-emitters with two-phase Monte Carlo simulations that combine site measurements collected with two approaches: unbiased sampling and targeted sampling of super-emitters. More comprehensive activity data and the inclusion of super-emitters, which account for 19% of O&G emissions, produces a emission inventory that is not statistically different than top-down regional emission estimates. Chapter 3 describes a helicopter-based survey of over 8,000 well pads in seven basins with infrared optical gas imaging to assess high emission sources. Four percent of sites are observed to have high emissions with over 90% of observed sources from tanks. The occurrence of high emissions is weakly correlated to site parameters and the best statistical model explains only 14% of variance, which demonstrates that the occurrence of super-emitters is primarily stochastic. Chapter 4 presents a Gaussian dispersion model for optimizing the placement of

  20. Achievement of ultralow emittance coupling in the Australian Synchrotron storage ring

    Directory of Open Access Journals (Sweden)

    R. Dowd

    2011-01-01

    Full Text Available Investigations into producing an electron beam with ultralow vertical emittance have been conducted using the Australian Synchrotron 3 GeV storage ring. A method of tuning the emittance coupling (ϵ_{y}/ϵ_{x} has been developed using a machine model calibrated through the linear optics from closed orbits method. Direct measurements of the beam emittance have not been possible due to diagnostic limitations, however two independent indirect measurements both indicate a vertical emittance of 1.2–1.3 pm rad (ϵ_{y}/ϵ_{x}=0.01%. Other indirect measurements support the validity of these results. This result is the smallest vertical emittance currently achieved in a storage ring.

  1. Measurements of Transverse Emittance for RF Photocathode Gun at the PAL

    CERN Document Server

    Park Jang Ho; Park, Sung-Ju; Soo Ko In; Wang, Xijie; Woon Parc, Yong; Xiang, Dao

    2005-01-01

    A BNL GUN-IV type RF photo-cathode gun is under fabrication for use in the FIR (Far Infra-Red) facility being built at the Pohang Accelerator Laboratory (PAL). Performance test of the gun will include the measurement of transverse emittance profile along the longitudinal direction. Successful measurement of the emittance profile will provide powerful tool for the commissioning of the 4GLS (4th generation light source) injectors based on the emittance compensation principle. We are going to achieve this withthe use of pepper-pot based emittance meters that can be moved along the longitudinal direction. In this article, we present design considerations on the emittance meter with the resolution of 1 mm mrad.

  2. Continuous air monitor for alpha-emitting aerosol particles

    International Nuclear Information System (INIS)

    McFarland, A.R.; Ortiz, C.A.; Rodgers, J.C.; Nelson, D.C.

    1991-01-01

    A new alpha continuous air monitor (CAM) sampler is being developed for use in detecting the presence of alpha-emitting aerosol particles. The effort involves design, fabrication and evaluation of systems for the collection of aerosol and for the processing of data to speciate and quantify the alpha emitters of the interest. At the present time the authors have a prototype of the aerosol sampling system and they have performed wind tunnel tests to characterize the performance of the device for different particle sizes, wind speeds, flow rates and internal design parameters. The results presented herein deal with the aerosol sampling aspects of the new CAM sampler. Wind tunnel tests show that ≥ 50% of 10 μm aerodynamic equivalent diameter (AED) particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L/min (2 cfm) and the wind speed is 1 m/s. The coefficient of variation of deposits of 10 μm AED aerosol particles on the collection filter is 7%. An inlet fractionator for removing high mobility background aerosol particles has been designed and successfully tested. The results show that it is possible to strip 95% of freshly formed radon daughters and 33% of partially aged radon daughters from the aerosol sample. This approach offers the opportunity to improve the signal-to-noise ratio in the alpha energy spectrum region of interest thereby enhancing the performance of background compensation algorithms

  3. Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

    International Nuclear Information System (INIS)

    Sill, C.W.

    1992-01-01

    Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described

  4. Aluminum oxide film thickness and emittance

    International Nuclear Information System (INIS)

    Thomas, J.K.; Ondrejcin, R.S.

    1991-11-01

    Aluminum reactor components which are not actively cooled could be subjected to high temperatures due to gamma heating after the core coolant level dropped during the ECS phase of a hypothetical LOCA event. Radiative heat transfer is the dominant heat transfer process in this scenario and therefore the emittance of these components is of interest. Of particular interest are the safety rod thimbles and Mark 60B blanket assemblies; for the K Reactor, these components have been exposed to low temperature (< 55 degrees C) moderator for about a year. The average moderator temperature was assumed to be 30 degrees C. The Al oxide film thickness at this temperature, after one year of exposure, is predicted to be 6.4 μm ± 10%; insensitive to exposure time. Dehydration of the film during the gamma heating accident would result in a film thickness of 6.0 μm ± 11%. Total hemispherical emittance is predicted to be 0.69 at 96 degrees C, decreasing to 0.45 at 600 degrees C. Some phenomena which would tend to yield thicker oxide films in the reactor environment relative to those obtained under experimental conditions were neglected and the predicted film thickness values are therefore conservative. The emittance values predicted for a given film thickness are also conservative. The conservativisms inherent in the predicted emittance are particularly relevant for uncertainty analysis of temperatures generated using these values

  5. Measured emittance dependence on injection method in laser plasma accelerators

    Science.gov (United States)

    Barber, Samuel; van Tilborg, Jeroen; Schroeder, Carl; Lehe, Remi; Tsai, Hai-En; Swanson, Kelly; Steinke, Sven; Nakamura, Kei; Geddes, Cameron; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

    2017-10-01

    The success of many laser plasma accelerator (LPA) based applications relies on the ability to produce electron beams with excellent 6D brightness, where brightness is defined as the ratio of charge to the product of the three normalized emittances. As such, parametric studies of the emittance of LPA generated electron beams are essential. Profiting from a stable and tunable LPA setup, combined with a carefully designed single-shot transverse emittance diagnostic, we present a direct comparison of charge dependent emittance measurements of electron beams generated by two different injection mechanisms: ionization injection and shock induced density down-ramp injection. Notably, the measurements reveal that ionization injection results in significantly higher emittance. With the down-ramp injection configuration, emittances less than 1 micron at spectral charge densities up to 2 pC/MeV were measured. This work was supported by the U.S. DOE under Contract No. DE-AC02-05CH11231, by the NSF under Grant No. PHY-1415596, by the U.S. DOE NNSA, DNN R&D (NA22), and by the Gordon and Betty Moore Foundation under Grant ID GBMF4898.

  6. Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

    Energy Technology Data Exchange (ETDEWEB)

    Thangaraj, J.; Ruan, J.; Johnson, A.S.; Thurman-Keup, R.; Lumpkin, A.H.; Santucci, J.; Sun, Y.-E; Maxwell, T.; Edwards, H.; /Fermilab

    2012-05-01

    Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

  7. Internal Auger emitters: effects on spermatogenesis and oogenesis in mice

    International Nuclear Information System (INIS)

    Rao, D.V.; Mylavarapu, V.B.; Sastry, K.S.R.; Howell, R.W.

    1988-01-01

    The in vivo biological effects of Auger emitters are investigated using [A] spermatogenesis in mouse testis, and [B] oogenesis in mouse ovary as experimental models. Spermhead survival and induction of abnormal sperm, following intratesticular administration of radiopharmaceuticals, were the end points in Model A. Of interest in Model B is primary oocyte survival after intraperitoneal injection of the radiochemicals. The effectiveness of the Auger emitter is determined relative to its beta emitting companion or external X-rays in the absence of such an analogue. Results reveal pronounced effects of Auger emitters on all end points, not dependent on mode of administration. The efficacy of the Auger emitter is related intimately to its subcellular distribution, which, is governed by the chemical form of the carrier molecule. Conventional dosimetry is inadequate and biophysically meaningful dosimetric approaches are needed to understand in vivo effects of Auger emitters. (author)

  8. Monte Carlo alpha calculation

    Energy Technology Data Exchange (ETDEWEB)

    Brockway, D.; Soran, P.; Whalen, P.

    1985-01-01

    A Monte Carlo algorithm to efficiently calculate static alpha eigenvalues, N = ne/sup ..cap alpha..t/, for supercritical systems has been developed and tested. A direct Monte Carlo approach to calculating a static alpha is to simply follow the buildup in time of neutrons in a supercritical system and evaluate the logarithmic derivative of the neutron population with respect to time. This procedure is expensive, and the solution is very noisy and almost useless for a system near critical. The modified approach is to convert the time-dependent problem to a static ..cap alpha../sup -/eigenvalue problem and regress ..cap alpha.. on solutions of a/sup -/ k/sup -/eigenvalue problem. In practice, this procedure is much more efficient than the direct calculation, and produces much more accurate results. Because the Monte Carlo codes are intrinsically three-dimensional and use elaborate continuous-energy cross sections, this technique is now used as a standard for evaluating other calculational techniques in odd geometries or with group cross sections.

  9. Interpreting HST observations with simulations of reionization: the ionizing photon budget and the decline of Lyman-alpha emission in z>6 dropouts

    Science.gov (United States)

    D'Aloisio, Anson

    2017-08-01

    In recent years, HST surveys such as CANDELS, HUDF, BoRG/HIPPIES, ERS, and the Frontier Fields, have made possible the first robust measurements of the rest-frame UV luminosity function of z =6-10 galaxies, spanning much of the redshift range over which reionization likely occurred. These measurements provide an estimate of the galactic ionizing photon output, addressing the critical question of whether these galaxies could have reionized the Universe. In addition, follow-up spectroscopy has measured the fraction of these galaxies that show Lyman-alpha emission. Interestingly, a dramatic decrease in this fraction above z 6 has been observed, and this evolution has (controversially) been interpreted as evidence that much of reionization happened over z=6-8 (as intergalactic neutral gas leads to large damping wings that scatter the Lyman-alpha line). The clumpiness of the IGM and how it self shields to ionizing photons impacts whether the observed population of galaxies can reionize the Universe, as well as the interpretation of the evolving Lyman-alpha emitter fraction. We propose to run fully coupled radiative-hydrodynamics simulations that are the first to resolve the evaporation of small structures by passing ionization fronts and, hence, to accurately assess the level of clumpiness and self-shielding from the IGM. Our study will nail down the clumping factor used to assess whether the observed population of galaxies can drive reionization, and it will address whether neutral self-shielding clumps in recently reionized regions can scatter galaxies' Lyman-alpha lines.

  10. Rossi Alpha Method

    International Nuclear Information System (INIS)

    Hansen, G.E.

    1985-01-01

    The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-α is no longer an α-eigenvalue

  11. Prototype Demonstration of Gamma- Blind Tensioned Metastable Fluid Neutron/Multiplicity/Alpha Detector – Real Time Methods for Advanced Fuel Cycle Applications

    Energy Technology Data Exchange (ETDEWEB)

    McDeavitt, Sean M. [Texas A & M Univ., College Station, TX (United States)

    2016-12-20

    The content of this report summarizes a multi-year effort to develop prototype detection equipment using the Tensioned Metastable Fluid Detector (TMFD) technology developed by Taleyarkhan [1]. The context of this development effort was to create new methods for evaluating and developing advanced methods for safeguarding nuclear materials along with instrumentation in various stages of the fuel cycle, especially in material balance areas (MBAs) and during reprocessing of used nuclear fuel. One of the challenges related to the implementation of any type of MBA and/or reprocessing technology (e.g., PUREX or UREX) is the real-time quantification and control of the transuranic (TRU) isotopes as they move through the process. Monitoring of higher actinides from their neutron emission (including multiplicity) and alpha signatures during transit in MBAs and in aqueous separations is a critical research area. By providing on-line real-time materials accountability, diversion of the materials becomes much more difficult. The Tensioned Metastable Fluid Detector (TMFD) is a transformational technology that is uniquely capable of both alpha and neutron spectroscopy while being “blind” to the intense gamma field that typically accompanies used fuel – simultaneously with the ability to provide multiplicity information as well [1-3]. The TMFD technology was proven (lab-scale) as part of a 2008 NERI-C program [1-7]. The bulk of this report describes the advancements and demonstrations made in TMFD technology. One final point to present before turning to the TMFD demonstrations is the context for discussing real-time monitoring of SNM. It is useful to review the spectrum of isotopes generated within nuclear fuel during reactor operations. Used nuclear fuel (UNF) from a light water reactor (LWR) contains fission products as well as TRU elements formed through neutron absorption/decay chains. The majority of the fission products are gamma and beta emitters and they represent the

  12. Alpha particles emitted from the surface of granite, clay, and its fired products, 1

    International Nuclear Information System (INIS)

    Aratani, Michi; Otsuka, Hideko

    1975-01-01

    As a part of an investigation on ''the effect of long-time irradiation from a trace amount of radioisotopes'', the emitting rate of alpha particles per unit surface area (apparent) coming from natural alpha-particle emitters has been measured. The samples measured were granite and its weathered product; clay, especially potter's clay, and its fired product; pottery ware. The values obtained were 39.1 +-0.9--0.73+-0.08 cpm/100 cm 2 in granite, 16.8+-0.4--6.4+-0.2 cpm/100cm 2 in potter's clay, and 1.36+-0.04--0.82+-0.04 cpm/100cm 2 in pottery ware on substrate, and 1.33+-0.05--0.32+-0.02 cpm/100cm 2 on glazer. (auth.)

  13. A numerical study of emittance growths in RF guns

    CERN Document Server

    Masuda, K; Sobajima, M; Kitagaki, J; Ohnishi, M; Toku, H; Yoshikawa, K

    1999-01-01

    A beam with greatly reduced emittance is required for further improvements of FELs, in particular, for FELs of shorter wavelengths, and of narrower bandwidths. From this viewpoint, the BNL/SLAC/UCLA 1.6-cell S-band photocathode RF gun performance characteristics were calculated, first in order to evaluate what may contribute to the emittance growths in photocathode RF guns. We developed an RF gun to produce an electron beam with an extremely low emittance, by using a 2-D simulation code. It is found that, by optimizing the laser injection phase, the drive laser spot radius and the cavity shape around the laser spot, the beam emittance by the 1.6-cell RF gun can be greatly reduced to 2.1 pi mm mrad, from the previous 4.4 pi mm mrad of the original shape.

  14. Simulation studies of emittance growth in RMS mismatched beams

    International Nuclear Information System (INIS)

    Cucchetti, A.; Wangler, T.; Reiser, M.

    1991-01-01

    As shown in a separate paper, a charged-particle beam, whose rms size is not matched when injected into a transport channel or accelerator, has excess energy compared with that of a matched beam. If nonlinear space-charge forces are present and the mismatched beam transforms to a matched equilibrium state, rms-emittance growth will occur. The theory yields formulas for the possible rms-emittance growth, but not for the time it takes to achieve this growth. In this paper we present the results of systematic simulation studies for a mismatched 2-D round beam in an ideal transport channel with continuous linear focusing. Emittance growth rates obtained from the simulations for different amounts of mismatch and initial charge will be presented and the emittance growth will be compared with the theory. 6 refs., 7 figs

  15. Low Emittance Tuning Studies for SuperB

    Energy Technology Data Exchange (ETDEWEB)

    Liuzzo, Simone; /INFN, Pisa; Biagini, Maria; /INFN, Rome; Raimondi, Pantaleo; /INFN, Rome; Donald, Martin; /SLAC

    2012-07-06

    SuperB[1] is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented.

  16. Arc-textured metal surfaces for high thermal emittance space radiators

    International Nuclear Information System (INIS)

    Banks, B.A.; Rutledge, S.K.; Mirtich, M.J.; Behrend, T.; Hotes, D.; Kussmaul, M.; Barry, J.; Stidham, C.; Stueber, T.; DiFilippo, F.

    1994-01-01

    Carbon arc electrical discharges struck across the surfaces of metals such as Nb-1% Zr, alter the morphology to produce a high thermal emittance surface. Metal from the surface and carbon from the arc electrode vaporize during arcing, and then condense on the metal surface to produce a microscopically rough surface having a high thermal emittance. Quantitative spectral reflectance measurements from 0.33 to 15 μm were made on metal surfaces which were carbon arc treated in an inert gas environment. The resulting spectral reflectance data were then used to calculate thermal emittance as a function of temperature for various methods of arc treatment. The results of arc treatment on various metals are presented for both ac and dc arcs. Surface characterization data, including thermal emittance as a function of temperature, scanning electron microscopy, and atomic oxygen durability, are also presented. Ac arc texturing was found to increase the thermal emittance at 800 K from 0.05. to 0.70

  17. Impact of water temperature and structural parameters on the hydraulic labyrinth-channel emitter performance

    Directory of Open Access Journals (Sweden)

    Ahmed I. Al-Amoud

    2014-06-01

    Full Text Available The effects of water temperature and structural parameters of a labyrinth emitter on drip irrigation hydraulic performance were investigated. The inside structural parameters of the trapezoidal labyrinth emitter include path width (W and length (L, trapezoidal unit numbers (N, height (H, and spacing (S. Laboratory experiments were conducted using five different types of labyrinth-channel emitters (three non-pressure compensating and two pressure-compensating emitters commonly used for subsurface drip irrigation systems. The water temperature effect on the hydraulic characteristics at various operating pressures was recorded and a comparison was made to identify the most effective structural parameter on emitter performance. The pressure compensating emitter flow exponent (x average was 0.014, while non-pressure compensating emitter’s values average was 0.456, indicating that the sensitivity of non-pressure compensating emitters to pressure variation is an obvious characteristic (p<0.001 of this type of emitters. The effects of water temperature on emitter flow rate were insignificant (p>0.05 at various operating pressures, where the flow rate index values for emitters were around one. The effects of water temperature on manufacturer’s coefficient of variation (CV values for all emitters were insignificant (p>0.05. The CV values of the non-pressure compensating emitters were lower than those of pressure compensating emitters. This is typical for most compensating models because they are manufactured with more elements than non-compensating emitters are. The results of regression analysis indicate that N and H are the essential factors (p<0.001 to affect the hydraulic performance.

  18. NEBULAR ATTENUATION IN H{alpha}-SELECTED STAR-FORMING GALAXIES AT z = 0.8 FROM THE NewH{alpha} SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Momcheva, Ivelina G. [Astronomy Department, Yale University, New Haven, CT 06511 (United States); Lee, Janice C.; Ouchi, Masami [Carnegie Observatories, Pasadena, CA 91101 (United States); Ly, Chun [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Salim, Samir [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Finn, Rose [Physics Department, Siena College, Loudonville, NY 12211 (United States); Ono, Yoshiaki, E-mail: ivelina.momcheva@yale.edu [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2013-02-01

    We present measurements of the dust attenuation of H{alpha}-selected emission-line galaxies at z = 0.8 from the NewH{alpha} narrowband survey. The analysis is based on deep follow-up spectroscopy with Magellan/IMACS, which captures the strong rest-frame optical emission lines from [O II] {lambda}3727 to [O III] {lambda}5007. The spectroscopic sample used in this analysis consists of 341 confirmed H{alpha} emitters. We place constraints on the active galactic nucleus (AGN) fraction using diagnostics that can be applied at intermediate redshift. We find that at least 5% of the objects in our spectroscopic sample can be classified as AGNs and 2% are composite, i.e., powered by a combination of star formation and AGN activity. We measure the dust attenuation for individual objects from the ratios of the higher order Balmer lines. The H{beta} and H{gamma} pair of lines is detected with S/N > 5 in 55 individual objects and the H{beta} and H{delta} pair is detected in 50 individual objects. We also create stacked spectra to probe the attenuation in objects without individual detections. The median attenuation at H{alpha} based on the objects with individually detected lines is A(H{alpha}) = 0.9 {+-} 1.0 mag, in good agreement with the attenuation found in local samples of star-forming galaxies. We find that the z = 0.8 galaxies occupy a similar locus of attenuation as a function of magnitude, mass, and star formation rate (SFR) as a comparison sample drawn from the SDSS DR4. Both the results from the individual z = 0.8 galaxies and from the stacked spectra show consistency with the mass-attenuation and SFR-attenuation relations found in the local universe, indicating that these relations are also applicable at intermediate redshift.

  19. Radiotoxicity of gadolinium-148 and radium-223 in mouse testes: Relative biological effectiveness of alpha-particle emitters in vivo

    International Nuclear Information System (INIS)

    Howell, R.W.; Goddu, S.M.; Narra, V.R.

    1997-01-01

    The biological effects of radionuclides that emit α particles are of considerable interest in view of their potential for therapy and their presence in the environment. The present work is a continuation of our ongoing effort to study the radiotoxicity of α-particle emitters in vivo using the survival of murine testicular sperm heads as the biological end point. Specifically, the relative biological effectiveness (RBE) of very low-energy α particles (3.2 MeV) emitted by 148 Gd is investigated and determined to be 7.4 ± 2.4 when compared to the effects of acute external 120 kVp X rays. This datum, in conjunction with our earlier results for 210 Po and 212 Pb in equilibrium with its daughters, is used to revise and extend the range of validity of our previous RBE-energy relationship for α particles emitted by tissue-incorporated radionuclides. The new empirical relationship is given by RBE α = 9.14 - 0.510 E α , where 3 α 223 Ra (in equilibrium with its daughters) experimentally in the same biological model and comparing the value obtained experimentally with the predicted value. The resulting RBE values are 5.4 ± 0.9 and 5.6, respectively. This close agreement strongly supports the adequacy of the empirical RBE-E α relationship to predict the biological effects of α-particle emitters in vivo. 42 refs., 5 figs., 1 tab

  20. On the design guideline for the low emittance synchrotron radiation source

    International Nuclear Information System (INIS)

    Kamiya, Y.; Kihara, M.

    1983-09-01

    In this note we will describe how the emittance of the electron storage ring is determined by the orbit parameters of the storage ring and show the lowest value of emittance which is achieved theoretically. Implication of this note with regard to the design of the low emittance storage ring will be discussed. (author)

  1. Homogeneous Gaussian Profile P+-Type Emitters: Updated Parameters and Metal-Grid Optimization

    Directory of Open Access Journals (Sweden)

    M. Cid

    2002-10-01

    Full Text Available P+-type emitters were optimized keeping the base parameters constant. Updated internal parameters were considered. The surface recombination velocity was considered variable with the surface doping level. Passivated homogeneous emitters were found to have low emitter recombination density and high collection efficiency. A complete structure p+nn+ was analyzed, taking into account optimized shadowing and metal-contacted factors for laboratory cells as function of the surface doping level and the emitter thickness. The base parameters were kept constant to make the emitter characteristics evident. The most efficient P+-type passivated homogeneous emitters, provide efficiencies around 21% for a wide range of emitter sheet resistivity (50 -- 500 omega/ with the surface doping levels Ns=1×10(19 cm-3 and 5×10(19 cm-3. The output electrical parameters were evaluated considering the recently proposed value n i=9.65×10(9 (cm-3. A non-significant increase of 0.1% in the efficiency was obtained, validating all the conclusions obtained in this work, considering n i=1×10(10 cm-3.

  2. Minimum emittance of three-bend achromats

    International Nuclear Information System (INIS)

    Li Xiaoyu; Xu Gang

    2012-01-01

    The calculation of the minimum emittance of three-bend achromats (TBAs) made by Mathematical software can ignore the actual magnets lattice in the matching condition of dispersion function in phase space. The minimum scaling factors of two kinds of widely used TBA lattices are obtained. Then the relationship between the lengths and the radii of the three dipoles in TBA is obtained and so is the minimum scaling factor, when the TBA lattice achieves its minimum emittance. The procedure of analysis and the results can be widely used in achromats lattices, because the calculation is not restricted by the actual lattice. (authors)

  3. Radiobiological long-term accumulation of environmental alpha radioactivity in extracted human teeth and animal bones in Malaysia.

    Science.gov (United States)

    Almayahi, B A; Tajuddin, A A; Jaafar, M S

    2014-03-01

    In this study, the radiobiological analysis of natural alpha emitters in extracted human teeth and animal bones from Malaysia was estimated. The microdistributions of alpha particles in tooth and bone samples were measured using CR-39 alpha-particle track detectors. The lowest and highest alpha emission rates in teeth in the Kedah and Perak states were 0.0080 ± 0.0005 mBq cm(-2) and 0.061 ± 0.008 mBq cm(-2), whereas those of bones in the Perlis and Kedah states were 0.0140 ± 0.0001 mBq cm(-2) and 0.7700 ± 0.0282 mBq cm(-2), respectively. The average alpha emission rate in male teeth was 0.0209 ± 0.0008 mBq cm(-2), whereas that of female teeth was 0.0199 ± 0.0010 mBq cm(-2). The alpha emission rate in teeth is higher in smokers (0.0228 ± 0.0008 mBq cm(-2)) than in non-smokers (0.0179 ± 0.0008 mBq cm(-2)). Such difference was found statistically significant (p < 0.01). Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. High emittance black nickel coating on copper substrate for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Somasundaram, Soniya, E-mail: jrf0013@isac.gov.in; Pillai, Anju M., E-mail: anjum@isac.gov.in; Rajendra, A., E-mail: rajendra@isac.gov.in; Sharma, A.K., E-mail: aks@isac.gov.in

    2015-09-15

    Highlights: • High emittance black nickel coating is obtained on copper substrate. • The effect of various process parameters on IR emittance is studied systematically. • Process parameters are optimized to develop a high emittance black nickel coating. • Coating obtained using the finalized parameters exhibited an emittance of 0.83. • SEM and EDAX are used for coating characterization. - Abstract: Black nickel, an alloy coating of zinc and nickel, is obtained on copper substrate by pulse electrodeposition from a modified Fishlock bath containing nickel sulphate, nickel ammonium sulphate, zinc sulphate and ammonium thiocyanate. A nickel undercoat of 4–5 μm thickness is obtained using Watts bath to increase the corrosion resistance and adhesion of the black nickel coating. The effect of bath composition, temperature, solution pH, current density and plating time on the coating appearance and corresponding infra-red emittance of the coating is investigated systematically. Process parameters are optimized to develop a high emittance space worthy black nickel coating to improve the heat radiation characteristics. The effect of the chemistry of the plating bath on the coating composition was studied using energy dispersive X-ray analysis (EDAX) of the coatings. The 5–6 μm thick uniform jet black zinc–nickel alloy coating obtained with optimized process exhibited an emittance of 0.83 and an absorbance of 0.92. The zinc to nickel ratio of black nickel coatings showing high emittance and appealing appearance was found to be in the range 2.3–2.4.

  5. Emittance measuring unit for 100% duty factor linac injector beams

    Energy Technology Data Exchange (ETDEWEB)

    Shubaly, M R; Pachner, J Jr; Ormrod, J H; Ungrin, J; Schriber, S O [ed.

    1976-11-01

    A description is given of a system to measure the emittance of a 750 keV 100 mA dc proton beam suitable for injection into a 100% duty factor linear accelerator. A relatively slowly pulsed 45/sup 0/ magnet switches the beam to a beam dump inside the emittance measuring unit for approx. 10 s. A fast pulsed 5/sup 0/ magnet then deflects the beam to a multiple aperture ''pepper-pot'' plate for 300 ..mu..s. Beamlets passing through the plate travel 520 mm and produce a pattern on a scintillator screen. A photograph of the pattern is analyzed to determine beam emittance. Preliminary results on low current beams show a gross increase in the emittance in the horizontal plane.

  6. An Online Multisensor Data Fusion Framework for Radar Emitter Classification

    Directory of Open Access Journals (Sweden)

    Dongqing Zhou

    2016-01-01

    Full Text Available Radar emitter classification is a special application of data clustering for classifying unknown radar emitters in airborne electronic support system. In this paper, a novel online multisensor data fusion framework is proposed for radar emitter classification under the background of network centric warfare. The framework is composed of local processing and multisensor fusion processing, from which the rough and precise classification results are obtained, respectively. What is more, the proposed algorithm does not need prior knowledge and training process; it can dynamically update the number of the clusters and the cluster centers when new pulses arrive. At last, the experimental results show that the proposed framework is an efficacious way to solve radar emitter classification problem in networked warfare.

  7. Transverse emittance dilution due to coupler kicks in linear accelerators

    Directory of Open Access Journals (Sweden)

    Brandon Buckley

    2007-11-01

    Full Text Available One of the main concerns in the design of low emittance linear accelerators (linacs is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternate from above to below the beam pipe so as to cancel each individual kick. While this is correct, including two couplers per cavity or alternating the coupler location requires large technical changes and increased cost for superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We therefore analyze consequences of alternate coupler placements. We show here that alternating the coupler location from above to below compensates the emittance growth as well as the orbit distortions. For sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. We show that cancellations hold for sufficiently large Q values. These compensations hold even when each cavity is individually detuned, e.g., by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick so as to minimize the effects on emittance from each coupler. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the

  8. Emittance and trajectory control in the main linacs of the NLC

    International Nuclear Information System (INIS)

    Assmann, R.; Adolphsen, C.; Bane, K.; Raubenheimer, T.O.; Thompson, K.

    1996-09-01

    The main linacs of the next generation of linear colliders need to accelerate the particle beams to energies of up to 750 GeV while maintaining very small emittances. This paper describes the main mechanisms of static emittance growth in the main linacs of the Next Linear Collider (NLC). The authors present detailed simulations of the trajectory and emittance control algorithms that are foreseen for the NLC. They show that the emittance growth in the main linacs can be corrected down to about 110%. That number is significantly better than required for the NLC design luminosity

  9. Radon Daughters Background Reduction in Alpha Particles Counting System

    International Nuclear Information System (INIS)

    Dadon, S. S.; Pelled, O.; Orion, I.

    2014-01-01

    The ABPC method is using a serially occurring events of the beta decay of the 214Bi fallow by alpha decay of the 214Po that take place almost simultaneously to detect the Pseudo Coincidence Event (PCE) from the RDP, and to subtract them from the gross alpha counts. 267 This work showed that it is possible to improve the efficiency of RDP background reduction, including subtracting the 218Po contribution by using the ABPC method based on a single solid state silicon PIPS detector. False counts percentage obtained at the output of the PCE circuit were smaller than 0.1%. The results show that the PCE circuit was not influenced by non RDP alpha emitters. The PCE system did not reduce the non PCE of the 218Po. After 20 minutes the 218Po was strongly decayed, and its contribution became negligible. In order to overcome this disadvantage, a mathematical matching calculations for the 214Po and the 218Po decay equations were employed, and a constant ratio of the APo214(0) / APo218(0) was obtained. This ratio can be used to estimate the count rate of the 218Po at the first 20 minutes, and to subtract it from the total count rate in order to obtain correct RDP reduction

  10. Management of alpha-contaminated wastes

    International Nuclear Information System (INIS)

    1980-01-01

    : 1) As regards the definition what is an alpha-bearing waste, it seemed that a number of participants were supporting the idea that such a value might be based on the concept of the MPC (maximum permissible concentration) - for drinkable water - and that the radioactivity of these wastes might be expressed in such a way in view of the conditioning and the disposal requirements. 2) It was the consensus that it is necessary to prevent production of large amounts of alpha-bearing wastes by improving the engineering and operational procedures of the reprocessing units and of the fuel fabrication plants, and to recover the major part of alpha emitters (plutonium) from the wastes by recycling. 3) As far as the treatment of such wastes is concerned, methods for reducing the volume have been improved. Techniques for sectioning large items and decontamination processes are now available Incineration at low temperature has proved its efficiency for the volume reduction Slagging incineration and acid digestion are also ready for an industrial development. 4) With regard to the conditioning it appeared that, in addition to the borosilicate glasses which are developed to industrial scale in France, several other matrices are under consideration and the first results are very promising. These matrices include vitreous and crystalline ceramics and synthetic rock materials. A substantial effort has been done in this field to ensure the quality of the final waste form for disposal. 5) For the monitoring of alpha emitters in the waste, several techniques are applicable at industrial level; they include gamma spectrography and passive neutron counting. Active neutron assay is under improvement and the results are very promising. A new technique is also under consideration using linear accelerator technology to detect trace amounts of transuranics in waste barrels. 6) As regards the actinide partitioning from high-level waste, great progress was made at laboratory scale using different

  11. Internal dynamics and emittance growth in space-charge-dominated beams

    International Nuclear Information System (INIS)

    Anderson, O.A.

    1987-01-01

    Previous analytical studies have related transverse rms emittance growth in nonuniform beams to changes in the beam density profile, but the time evolution of the process has not been analyzed. Our new approach analyzes the internal motion of the beam and from this obtains the explicit time dependence of the rms emittance. It is shown to reach its peak value explosively in about one quarter of a plasma period. The subsequent behavior depends on the uniformity of the initial density profile. We derive a uniformity criterion that determines whether or not the emittance oscillates periodically and present examples of density profiles for which the emittance returns to its initial value and then continues to oscillate. We discuss a class of continuous initial profiles that lead to discontinuous shocklike behavior (with partial irreversibility of the oscillations) and a class of segmented profiles for which the emittance jumps to its maximum value in one fourth of a plasma period and remains at that value with essentially no further change. (author)

  12. Modular low-voltage electron emitters

    International Nuclear Information System (INIS)

    Berejka, Anthony J.

    2005-01-01

    Modular, low-voltage electron emitters simplify electron beam (EB) technology for many industrial uses and for research and development. Modular electron emitters are produced in quantity as sealed systems that are evacuated at the factory, eliminating the need for vacuum pumps at the point of use. A plug-out-plug-in method of replacement facilitates servicing. By using an ultra-thin 6-7 μm titanium foil window, solid-state power supplies, an innovative design to extract and spread the beam (enabling systems to be placed adjacent to each other to extend beam width) and touch-screen computer controls, these modular units combine ease of use and electrical transfer efficiency at voltages that can be varied between 80 kV and 150 kV with beam currents up to 40 mA per 25 cm across the beam window. These new devices have been made in three widths: 5 cm, 25 cm, and 40 cm. Details of the beam construction and illustrations of industrial uses will be presented. Traditional uses in the graphic arts and coatings areas have welcomed this modular technology as well as uses for surface sterilization. Being compact and lightweight (∼15 kg/emitter), these modular beams have been configured around complex shapes to achieve three-dimensional surface curing at high production rates

  13. Modular low-voltage electron emitters

    Science.gov (United States)

    Berejka, Anthony J.

    2005-12-01

    Modular, low-voltage electron emitters simplify electron beam (EB) technology for many industrial uses and for research and development. Modular electron emitters are produced in quantity as sealed systems that are evacuated at the factory, eliminating the need for vacuum pumps at the point of use. A plug-out-plug-in method of replacement facilitates servicing. By using an ultra-thin 6-7 μm titanium foil window, solid-state power supplies, an innovative design to extract and spread the beam (enabling systems to be placed adjacent to each other to extend beam width) and touch-screen computer controls, these modular units combine ease of use and electrical transfer efficiency at voltages that can be varied between 80 kV and 150 kV with beam currents up to 40 mA per 25 cm across the beam window. These new devices have been made in three widths: 5 cm, 25 cm, and 40 cm. Details of the beam construction and illustrations of industrial uses will be presented. Traditional uses in the graphic arts and coatings areas have welcomed this modular technology as well as uses for surface sterilization. Being compact and lightweight (∼15 kg/emitter), these modular beams have been configured around complex shapes to achieve three-dimensional surface curing at high production rates.

  14. Beam dynamics in rf guns and emittance correction techniques

    International Nuclear Information System (INIS)

    Serafini, L.

    1994-01-01

    In this paper we present a general review of beam dynamics in a laser-driven rf gun. The peculiarity of such an accelerating structure versus other conventional multi-cell linac structures is underlined on the basis of the Panofsky-Wenzel theorem, which is found to give a theoretical background for the well known Kim's model. A basic explanation for some proposed methods to correct rf induced emittance growth is also derived from the theorem. We also present three emittance correction techniques for the recovery of space-charge induced emittance growth, namely the optimum distributed disk-like bunch technique, the use of rf spatial harmonics to correct spherical aberration induced by space charge forces and the technique of emittance filtering by clipping the electron beam. The expected performances regarding the beam quality achievable with different techniques, as predicted by scaling laws and simulations, are analyzed, and, where available, compared to experimental results. (orig.)

  15. Transverse emittance measurement at REGAE via a solenoid scan

    Energy Technology Data Exchange (ETDEWEB)

    Hachmann, Max

    2012-12-15

    The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required. A quantity to rate the beam quality is the beam emittance. In the course of this thesis transverse emittance measurements by a solenoid scan could be realized and beyond that an improved theoretical description of a solenoid was successful. The foundation of emittance measurements are constituted by theoretical models which describe the envelope of a beam. Two different models were derived. The first is an often used model to determine the transverse beam emittance without considering space charge effects. More interesting and challenging was the development of an envelope model taking space charge effects into account. It is introduced and cross checked with measurements and simulations.

  16. Laser-assisted electron emission from gated field-emitters

    CERN Document Server

    Ishizuka, H; Yokoo, K; Mimura, H; Shimawaki, H; Hosono, A

    2002-01-01

    Enhancement of electron emission by illumination of gated field-emitters was studied using a 100 mW cw YAG laser at a wavelength of 532 nm, intensities up to 10 sup 7 W/m sup 2 and mechanically chopped with a rise time of 4 mu s. When shining an array of 640 silicon emitters, the emission current responded quickly to on-off of the laser. The increase of the emission current was proportional to the basic emission current at low gate voltages, but it was saturated at approx 3 mu A as the basic current approached 100 mu A with the increase of gate voltage. The emission increase was proportional to the square root of laser power at low gate voltages and to the laser power at elevated gate voltages. For 1- and 3-tip silicon emitters, the rise and fall of the current due to on-off of the laser showed a significant time lag. The magnitude of emission increase was independent of the position of laser spot on the emitter base and reached 2 mu A at a basic current of 5 mu A without showing signs of saturation. The mech...

  17. Lower critical solution temperature behavior of alpha-substituted poly(acrylic acids)s, cyclopolymerization of N-vinylformamido-methylacrylates, and use of the World-Wide Web in polymer science education

    Science.gov (United States)

    Michalovic, Mark Stephen

    A series of alpha-substituted poly(acrylic acid)s was synthesized and characterized. Their aqueous solution properties were investigated with respect to lower critical solution temperature (LCST) behavior. Poly(alpha-methoxymethylacrylic acid) was found to have a lower critical solution temperature (LCST) of 46°C, poly(alpha-methoxyethoxymethylacrylic acid) showed an LCST of 26.5°C and poly(alpha-methoxyethoxyethoxymethylacrylic acid) showed an LCST of 66°C. The cloud points of the solutions of these polymers were found to be sensitive to pH, and to concentrations of additives such as urea, salts, and surfactants. Because of low molecular weight due to chain transfer, high molecular weight analogs of the ether-linked polymers were synthesized in which ester linkages joined the oligo-oxyethylene segment to the acrylate moiety. Poly(alpha-methoxyethoxyacetoxymethylacrylic acid) was the only one of this series to give an LCST with a value of 52.5°C. Copolymers of t-butyl alpha-methoxymethylacrylate (tBMMA) with alpha-(1H,1H- perfluorooctyloxymethyl)acrylic acid (PFOMA) were synthesized, deprotected and their lower critical solution temperatures (LCSTs) evaluated. At PFOMA feed ratios of 0.25 mol % or less, no observable change in the LCST was observed, while at PFOMA feed ratios of above 0.25 mol % to 1.125 mol %, a large linear decrease in the LCST was observed with increasing fluorocarbon content. t-Butyl alpha-(N-vinylformamidomethyl)acrylate (tBVFA) and ethyl alpha-(N-vinylformamidomethyl)acrylate (EVFA) were synthesized from t-butyl alpha-bromomethylacrylate and ethyl alpha-chloromethylacrylate, respectively. tBVFA was found to cyclopolymerize at 120°C in DMF, DMSO, and 1,2-dichlorobenzene at solvent:monomer ratios of 10:1 vol:wt. Molecular weights for poly(tBVFA) ranged from 10,000 to 13,000 as estimated by size-exclusion chromatography. At lower solvent monomer ratio (1:1), and at lower temperature (71°C), crosslinking occurred. EVFA was found to

  18. Preservation of low slice emittance in bunch compressors

    Directory of Open Access Journals (Sweden)

    S. Bettoni

    2016-03-01

    Full Text Available Minimizing the dilution of the electron beam emittance is crucial for the performance of accelerators, in particular for free electron laser facilities, where the length of the machine and the efficiency of the lasing process depend on it. Measurements performed at the SwissFEL Injector Test Facility revealed an increase in slice emittance after compressing the bunch even for moderate compression factors. The phenomenon was experimentally studied by characterizing the dependence of the effect on beam and machine parameters relevant for the bunch compression. The reproduction of these measurements in simulation required the use of a 3D beam dynamics model along the bunch compressor that includes coherent synchrotron radiation. Our investigations identified transverse effects, such as coherent synchrotron radiation and transverse space charge as the sources of the observed emittance dilution, excluding other effects, such as chromatic effects on single slices or spurious dispersion. We also present studies, both experimental and simulation based, on the effect of the optics mismatch of the slices on the variation of the slice emittance along the bunch. After a corresponding reoptimization of the beam optics in the test facility we reached slice emittances below 200 nm for the central slices along the longitudinal dimension with a moderate increase up to 300 nm in the head and tail for a compression factor of 7.5 and a bunch charge of 200 pC, equivalent to a final current of 150 A, at about 230 MeV energy.

  19. Coupling of Quantum Emitters in Nanodiamonds to Plasmonic Structures

    DEFF Research Database (Denmark)

    Kumar, Shailesh

    This PhD thesis describes work towards the enhancement and efficient channeling of photons emitted from a single photon emitter. The emitter used is a defect center, the Nitrogen-Vacancy (NV) center, in diamond. The NV-center has many unique properties, such as long coherence time of its electron...

  20. Determination of beta-ray emitter concentrations in bioassay samples of the victims in JCO criticality accident

    International Nuclear Information System (INIS)

    Yukawa, Masae; Nishimura, Yoshikazu; Watanabe, Yoshito

    2001-01-01

    Concentrations of neutron-induced β-ray emitters in the hair, blood, urine and bone of three workers severely exposed to neutrons in JCO criticality accident were measured with a low background β-ray spectrometer (Pico β) and liquid scintillation counter for the purpose of neutron dose estimation. 32 P is generated by the fast neutron of 2.5 MeV and over in sulfur with (n, p) reaction. Since content of sulfur in hair is high as compared with the other human tissues, we tried to estimate fast neutron fluence to the body surface of the victims using concentrations of 32 P and stable sulfur in their hair. The result shows that two workers, who were exposed to the higher neutron radiation than another worker, received higher doses of irradiation to the frontal side of their trunks than to the heads. For a more detailed mapping of neutron fluence in the body, the measurements of 32 P and 45 Ca induced by (n, γ) reaction in bone were carried out. The results show that one worker (worker A) received a higher dose of neutrons at the frontal right side of the trunk, and that the dose decreased with the distance from the central part of the body. The other (worker B) seems to have gotten a higher dose of irradiation in the face, hands and waist. High amount of 32 P was detected in urine of the workers, and the concentration gradient among three workers showed a similar tendency to the estimated neutron dose from 24 Na in blood. Therefore, radioactivity of 32 P in urine could be used for estimating the neutron exposure dose. Moreover, the activity can be easily determined by scintillation counting, and urine is less invading bioassay sample that can be collected by non-medical stuffs. (author)

  1. Emittance growth due to dipole ripple and sextupole

    International Nuclear Information System (INIS)

    Shih, H.J.; Ellison, J.A.; Syphers, M.J.; Newberger, B.S.

    1993-05-01

    Ripple in the power supplies for storage ring magnets can have adverse effects on the circulating beams: orbit distortion and emittance growth from dipole ripple, tune modulation and dynamic aperture reduction from quadrupole ripple, etc. In this paper, we study the effects of ripple in the horizontal bending field of the SSC in the presence of nonlinearity, in particular, the growth in beam emittance

  2. Multibunch emittance growth and its corrections in S-Band linear collider

    International Nuclear Information System (INIS)

    Gao, J.

    1994-11-01

    Multibunch emittance growths caused by long range wake fields with the misalignments of accelerating structures and quadrupoles in S-Band linear collider are studied. Tolerances for the misalignment errors of accelerating structures and quadrupoles are given corresponding to different detuned+damped structures. At the end of main linac, emittance corrector (EC) is proposed to be used to reduce further the multibunch emittance. Numerical simulations show that the effect of EC is obvious (multibunch emittance can be reduced about one order of magnitude), and it is believed that this kind of EC will be necessary for future linear colliders. (author). 16 refs., 21 figs., 4 tabs

  3. Emittance Measurements from a Laser Driven Electron Injector

    Energy Technology Data Exchange (ETDEWEB)

    Reis, David A

    2003-07-28

    The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center was constructed to develop an appropriate electron beam suitable for driving a short wavelength free electron laser (FEL) such as the proposed Linac Coherent Light Source (LCLS). For operation at a wavelength of 1.5 {angstrom}, the LCLS requires an electron injector that can produce an electron beam with approximately 1 {pi} mm-mrad normalized rms emittance with at least 1 nC of charge in a 10 ps or shorter bunch. The GTF consists of a photocathode rf gun, emittance-compensation solenoid, 3 m linear accelerator (linac), drive laser, and diagnostics to measure the beam. The rf gun is a symmetrized 1.6 cell, s-band high gradient, room temperature, photocathode structure. Simulations show that this gun when driven by a temporally and spatially shaped drive laser, appropriately focused with the solenoid, and further accelerated in linac can produce a beam that meets the LCLS requirements. This thesis describes the initial characterization of the laser and electron beam at the GTF. A convolved measurement of the relative timing between the laser and the rf phase in the gun shows that the jitter is less than 2.5 ps rms. Emittance measurements of the electron beam at 35 MeV are reported as a function of the (Gaussian) pulse length and transverse profile of the laser as well as the charge of the electron beam at constant phase and gradient in both the gun and linac. At 1 nC the emittance was found to be {approx} 13 {pi} mm-mrad for 5 ps and 8 ps long laser pulses. At 0.5 nC the measured emittance decreased approximately 20% in the 5 ps case and 40% in the 8 ps case. These measurements are between 40-80% higher than simulations for similar experimental conditions. In addition, the thermal emittance of the electron beam was measured to be 0.5 {pi} mm-mrad.

  4. Quadrupole Transfer Function for Emittance Measurement

    CERN Document Server

    Cameron, Peter; Jansson, Andreas; Tan, Cheng-Yang

    2008-01-01

    Historically the use of the quadrupole moment measurement has been impeded by the requirement for large dynamic range, as well as measurement sensitivity to beam position. We investigate the use of the transfer function technique [1-3] in combination with the sensitivity and 160dB revolution line rejection of the direct diode detection analog front end [4] to open the possibility of an emittance diagnostic that may be implemented without operational complication, quasi- parasitic to the operation of existing tune measurement systems. Such a diagnostic would be particularly useful as an emittance monitor during acceleration ramp development in machines like RHIC and the LHC.

  5. Emitter/absorber interface of CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Song, Tao, E-mail: tsong241@gmail.com; Sites, James R. [Physics Department, Colorado State University, Fort Collins, Colorado 80523 (United States); Kanevce, Ana [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

    2016-06-21

    The performance of CdTe solar cells can be very sensitive to the emitter/absorber interface, especially for high-efficiency cells with high bulk lifetime. Performance losses from acceptor-type interface defects can be significant when interface defect states are located near mid-gap energies. Numerical simulations show that the emitter/absorber band alignment, the emitter doping and thickness, and the defect properties of the interface (i.e., defect density, defect type, and defect energy) can all play significant roles in the interface recombination. In particular, a type I heterojunction with small conduction-band offset (0.1 eV ≤ ΔE{sub C} ≤ 0.3 eV) can help maintain good cell efficiency in spite of high interface defect density, much like with Cu(In,Ga)Se{sub 2} (CIGS) cells. The basic principle is that positive ΔE{sub C}, often referred to as a “spike,” creates an absorber inversion and hence a large hole barrier adjacent to the interface. As a result, the electron-hole recombination is suppressed due to an insufficient hole supply at the interface. A large spike (ΔE{sub C} ≥ 0.4 eV), however, can impede electron transport and lead to a reduction of photocurrent and fill-factor. In contrast to the spike, a “cliff” (ΔE{sub C} < 0 eV) allows high hole concentration in the vicinity of the interface, which will assist interface recombination and result in a reduced open-circuit voltage. Another way to mitigate performance losses due to interface defects is to use a thin and highly doped emitter, which can invert the absorber and form a large hole barrier at the interface. CdS is the most common emitter material used in CdTe solar cells, but the CdS/CdTe interface is in the cliff category and is not favorable from the band-offset perspective. The ΔE{sub C} of other n-type emitter choices, such as (Mg,Zn)O, Cd(S,O), or (Cd,Mg)Te, can be tuned by varying the elemental ratio for an optimal positive value of ΔE{sub C}. These

  6. Ion concentration in micro and nanoscale electrospray emitters.

    Science.gov (United States)

    Yuill, Elizabeth M; Baker, Lane A

    2018-06-01

    Solution-phase ion transport during electrospray has been characterized for nanopipettes, or glass capillaries pulled to nanoscale tip dimensions, and micron-sized electrospray ionization emitters. Direct visualization of charged fluorophores during the electrospray process is used to evaluate impacts of emitter size, ionic strength, analyte size, and pressure-driven flow on heterogeneous ion transport during electrospray. Mass spectrometric measurements of positively- and negatively-charged proteins were taken for micron-sized and nanopipette emitters under low ionic strength conditions to further illustrate a discrepancy in solution-driven transport of charged analytes. A fundamental understanding of analyte electromigration during electrospray, which is not always considered, is expected to provide control over selective analyte depletion and enrichment, and can be harnessed for sample cleanup. Graphical abstract Fluorescence micrographs of ion migration in nanoscale pipettes while solution is electrosprayed.

  7. Liquid scintillation alpha counting and spectrometry and its application to bone and tissue samples

    International Nuclear Information System (INIS)

    McDowell, W.J.; Weiss, J.F.

    1976-01-01

    Three methods for determination of alpha-emitting nuclides using liquid scintillation counting are compared, and the pertinent literature is reviewed. Data showing the application of each method to the measurement of plutonium concentration in tissue and bone samples are presented. Counting with a commercial beta-liquid scintillation counter and an aqueous-phase-accepting scintillator is shown to be accurate only in cases where the alpha activity is high (several hundred counts/min or more), only gross alpha counting is desired, and beta-gamma emitters are known to be absent from the sample or present at low levels compared with the alpha activity. Counting with the same equipment and an aqueous immiscible scintillator containing an extractant for the nuclide of interest (extractive scintillator) is shown to allow better control of alpha peak shift due to quenching, a significant reduction of beta-gamma interference, and, usually, a low background. The desirability of using a multichannel pulse-height analyzer in the above two counting methods is stressed. The use of equipment and procedures designed for alpha liquid scintillation counting is shown to allow alpha spectrometry with an energy resolution capability of 200 to 300 keV full-peak-width-at-half-peak-height and a background of 0.3 to 1.0 counts/min, or as low as 0.01 counts/min if pulse-shape discrimination methods are used. Methods for preparing animal bone and tissue samples for assay are described

  8. Emittance of a finite scattering medium with refractive index greater than unity

    International Nuclear Information System (INIS)

    Crosbie, A.L.

    1980-01-01

    Refractive index and scattering can significantly influence the transfer of radiation in a semitransparent medium such as water, glass, plastics, or ceramics. In a recent article (1979), the author presented exact numerical results for the emittance of a semiinfinite scattering medium with a refractive index greater than unity. The present investigation extends the analysis to a finite medium. The physical situation consists of a finite planar layer. The isothermal layer emits, absorbs, and isotropically scatters thermal radiation. It is characterized by single scattering albedo, optical thickness, refractive index, and temperature. A formula for the directional emittance is derived, the directional emittance being the emittance of the medium multiplied by the interface transmittance. The ratio of hemispherical to normal emittance is tabulated and discussed

  9. MD2065: Emittance exchange with linear coupling

    CERN Document Server

    Carver, Lee Robert; Persson, Tobias Hakan Bjorn; Amorim, David; Levens, Tom; Pesah, Arthur Chalom; CERN. Geneva. ATS Department

    2018-01-01

    In order to better understand the luminosity imbalance between ATLAS and CMS that was observed in 2016, it was proposed to perform a test whereby the horizontal and vertical emittances are exchanged by crossing the tunes in the presence of linear coupling. The luminosity before and after the exchange could be compared to see if the imbalance stems purely from the uneven emittances or if there is an additional mechanism in play. However, due to limited machine availability only tests at injection were able to performed.

  10. A comparative study of the plasmon effect in nanoelectrode THz emitters: Pulse vs. continuous-wave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Kiwon; Lee, Eui Su; Lee, Il-Min; Han, Sang-Pil; Kim, Hyun-Soo; Park, Kyung Hyun, E-mail: khp@etri.re.kr [Terahertz Basic Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of); Choi, Jeongyong [Metal-Insulator Transition Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of); Lee, Donghun [Optical Internet Components Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of)

    2016-08-15

    Plasmonic field enhancement in terahertz (THz) generation is one of the recently arisen techniques in the THz field that has attracted considerable interest. However, the reported levels of enhancement of THz output power in the literature are significantly different from each other, from less than two times to about two orders of magnitude of enhancement in power, which implies the existence of other major limiting factors yet to be revealed. In this work, the contribution of the plasmonic effect to the power enhancement of THz emitters is revisited. We show that the carrier collection efficiency in a THz emitter with plasmonic nanostructures is more critical to the device performance than the plasmonic field enhancement itself. The strong reverse fields induced by the highly localized plasmonic carriers in the vicinity of the nanoelectrodes screen the carrier collections and seriously limit the power enhancement. This is supported by our experimental observations of the significantly enhanced power in a plasmonic nanoelectrode THz emitter in continuous-wave radiation mode, while the same device has limited enhancement with pulsed radiation. We hope that our study may provide an intuitive but practical guideline in adopting plasmonic nanostructures with an aim of enhancing the efficiency of optoelectronic devices.

  11. Prototype of a subsurface drip irrigation emitter: Manufacturing, hydraulic evaluation and experimental analyses

    Science.gov (United States)

    Souza, Wanderley De Jesus; Rodrigues Sinobas, Leonor; Sánchez, Raúl; Arriel Botrel, Tarlei; Duarte Coelho, Rubens

    2013-04-01

    Root and soil intrusion into the conventional emitters is one of the major disadvantages to obtain a good uniformity of water application in subsurface drip irrigation (SDI). In the last years, there have been different approaches to reduce these problems such as the impregnation of emitters with herbicide, and the search for an emitter geometry impairing the intrusion of small roots. Within the last this study, has developed and evaluated an emitter model which geometry shows specific physical features to prevent emitter clogging. This work was developed at the Biosystems Engineering Department at ESALQ-USP/Brazil, and it is a part of a research in which an innovated emitteŕs model for SDI has been developed to prevent root and soil particles intrusion. An emitter with a mechanical-hydraulic mechanism (opening and closing the water outlet) for SDI was developed and manufactured using a mechanical lathe process. It was composed by a silicon elastic membrane a polyethylene tube and a Vnyl Polychloride membrane protector system. In this study the performance of the developed prototype was assessed in the laboratory and in the field conditions. In the laboratory, uniformity of water application was calculated by the water emission uniformity coefficient (CUE), and the manufacturer's coefficient of variation (CVm). In addition, variation in the membrane diameter submitted to internal pressures; head losses along the membrane, using the energy equation; and, precision and accuracy of the equation model, analyzed by Pearson's correlation coefficient (r), and by Willmott's concordance index (d) were also calculated with samples of the developed emitters. In the field, the emitters were installed in pots with and without sugar cane culture from October 2010 to January 2012. During this time, flow rate in 20 emitters were measured periodically, and the aspects of them about clogging at the end of the experiment. Emitters flow rates were measured quarterly to calculate

  12. Radiobiological long-term accumulation of environmental alpha radioactivity in extracted human teeth and animal bones in Malaysia

    International Nuclear Information System (INIS)

    Almayahi, B.A.; Tajuddin, A.A.; Jaafar, M.S.

    2014-01-01

    In this study, the radiobiological analysis of natural alpha emitters in extracted human teeth and animal bones from Malaysia was estimated. The microdistributions of alpha particles in tooth and bone samples were measured using CR-39 alpha-particle track detectors. The lowest and highest alpha emission rates in teeth in the Kedah and Perak states were 0.0080 ± 0.0005 mBq cm −2 and 0.061 ± 0.008 mBq cm −2 , whereas those of bones in the Perlis and Kedah states were 0.0140 ± 0.0001 mBq cm −2 and 0.7700 ± 0.0282 mBq cm −2 , respectively. The average alpha emission rate in male teeth was 0.0209 ± 0.0008 mBq cm −2 , whereas that of female teeth was 0.0199 ± 0.0010 mBq cm −2 . The alpha emission rate in teeth is higher in smokers (0.0228 ± 0.0008 mBq cm −2 ) than in non-smokers (0.0179 ± 0.0008 mBq cm −2 ). Such difference was found statistically significant (p < 0.01). - Highlights: • Alpha emission rates in teeth from smokers slightly higher than non-smokers. • Difference between alpha rates in male and female tooth not statistically significant. • Alpha particles have the same effect at any age. • Difference between alpha rates in bones was statistically significant

  13. Numerical studies of emittance exchange in 2-D charged-particle beams

    International Nuclear Information System (INIS)

    Guy, F.W.

    1986-01-01

    We describe results obtained from a two-dimensional particle-following computer code that simulates a continuous, nonrelativistic, elliptical charged-particle beam with linear continuous focusing. Emittances and focusing strengths can be different in the two transverse directions. The results can be applied, for example, for a quadrupole transport system in a smooth approximation to a real beam with unequal emittances in the two planes. The code was used to study emittance changes caused by kinetic-energy exchange between transverse directions and by shifts in charge distributions. Simulation results for space-charge-dominated beams agree well with analytic formulas. From simulation results, an empirical formula was developed for a ''partition parameter'' (the ratio of kinetic energies in the two directions) as a function of initial conditions and beamline length. Quantitative emittance changes for each transverse direction can be predicted by using this parameter. Simulation results also agree with Hofmann's generalized differential equation relating emittance and field energy

  14. Growth rate of non-thermodynamic emittance of intense electron beams

    International Nuclear Information System (INIS)

    Carlsten, B.E.

    1998-01-01

    The nonlinear free-energy concept has been particularly useful in estimating the emittance growth resulting from any excess energy of electron beams in periodic and uniform channels. However, additional emittance growth, that is geometrical rather than thermodynamic in origin, is induced if the particles have different kinetic energies and axial velocities, which is common for mildly relativistic, very intense electron beams. This effect is especially strong if particles lose or gain significant kinetic energy due to the beam's potential depression, as the beam converges and diverges. In this paper we analyze these geometric emittance growth mechanisms for a uniform, continuous, intense electron beam in a focusing transport channel consisting of discrete solenoidal magnets, over distances short enough that the beam does not reach equilibrium. These emittance growth mechanisms are based on the effects of (1) energy variations leading to nonlinearities in the space-charge force even if the current density is uniform, (2) an axial velocity shear radially along the beam due to the beam's azimuthal motion in the solenoids, and (3) an energy redistribution of the beam as the beam compresses or expands. The geometric emittance growth is compared in magnitude with that resulting from the nonlinear free energy, for the case of a mismatched beam in a uniform channel, and is shown to dominate for certain experimental conditions. Rules for minimizing the emittance along a beamline are outlined. copyright 1998 The American Physical Society

  15. Measurement of the transverse emittance for the NSC Pelletron

    International Nuclear Information System (INIS)

    Rodriques, G.; Mandal, A.; Chopra, S.; Joshi, R.; Datta, S.K.; Roy, A.

    1998-01-01

    The knowledge of the emittance (transverse and longitudinal) of the NSC pelletron is essential for matching the acceptance of the LINAC which is to be installed to augment the pelletron beam energies. The transverse emittance of NSC pelletron has been measured by employing a focussing element and a down-stream beam profile monitor

  16. Low Cost Constant – Head Drip Irrigation Emitter for Climate ...

    African Journals Online (AJOL)

    Low Cost Constant – Head Drip Irrigation Emitter for Climate Change Adaptation in Nigeria: Engineering Design and Calibration. ... The drip system comprises of abarrel, sub-main line, lateral lines, tubes and emitters, it can irrigate140 crop ...

  17. Experimental studies on coherent synchrotron radiation at an emittance exchange beam line

    Science.gov (United States)

    Thangaraj, J. C. T.; Thurman-Keup, R.; Ruan, J.; Johnson, A. S.; Lumpkin, A. H.; Santucci, J.

    2012-11-01

    One of the goals of the Fermilab A0 photoinjector is to investigate experimentally the transverse to longitudinal emittance exchange (EEX) principle. Coherent synchrotron radiation in the emittance exchange line could limit the performance of the emittance exchanger at short bunch lengths. In this paper, we present experimental and simulation studies of the coherent synchrotron radiation (CSR) in the emittance exchange line at the A0 photoinjector. We report on time-resolved CSR studies using a skew-quadrupole technique. We also demonstrate the advantages of running the EEX with an energy-chirped beam.

  18. Water quality - Measurement of gross alpha activity in non-saline water - Thick source method. 2. ed.

    International Nuclear Information System (INIS)

    2007-01-01

    This International Standard specifies a method for the determination of gross alpha activity in non-saline waters for alpha-emitting radionuclides which are not volatile at 350 degree Centigrade. It is possible to determine supported volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species) and the duration of measurement (counting time). The method is applicable to raw and potable waters. The range of application depends on the amount of suspended matter in the water and on the performance characteristics (background count rate and counting efficiency) of the counter. Gross alpha radioactivity is determined by using proportional counting or solid scintillation counting on water residue deposited on a planchet. Due to the strong absorption of the residue deposit, it is considered that the alpha emission from the surface is proportional to the alpha activity of the deposit. Gross alpha determination is not an absolute determination of the sample alpha radioactive content, but a relative determination referring to a specific alpha emitter which constitutes the standard calibration source. This type of determination is also known as alpha index. The sample is acidified to stabilize it, evaporated almost to dryness, converted to the sulfate form and then ignited at 350 degree Centigrade. A portion of the residue is transferred to a planchet and the alpha activity measured by counting in an alpha-particle detector or counting system previously calibrated against an alpha-emitting standard and the alpha activity concentration calculated. The paper provides information about scope, normative references, symbols, definitions and units, principle, reagents and equipment, procedure, contamination check, expression of results and test report

  19. Monte Carlo modelling of damage to haemopoietic stem cells from internally deposited alpha-emitters

    International Nuclear Information System (INIS)

    Utteridge, T.D.; University of South Australia, Pooraka, SA; Charlton, D.E.; Turner, M.S.; Beddoe, A.H.; Leong, A. S-Y.; Milios, J.; Fazzalari, N.; To, L.B.

    1996-01-01

    Full text: Monte Carlo modelling of alpha particle radiation dose to haemopoietic stem cells from radon decay in human marrow fat cells was undertaken following Richardson et al's (Brit J Radiol, 64, 608-624, 1991) proposition that such exposure could induce leukaemia, and epidemiological observations that uranium miners have not developed an excess of leukaemia (Tomasek L. et al, Lancet, 341, 919-923, 1993). The dose to haemopoietic stem cells from alpha emitting radiopharmaceuticals proposed for radiotherapy is also important in risk assessment. Haemopoietic stem cells (presumed to be the targets for leukaemia) were identified as CD34+CD38- mononuclear cells (Terstappen LWMM et al, Blood, 77, 1218-1227, 1991) and their diameters measured using image analysis. The distribution of stem cell distances from fat cells was also measured. The model was used with Monte Carlo treatment of the alpha particle flux from radon and its short lived decay products to estimate (a) the dose and LET distributions for the three stem cell diameters; (b) the number of passages per hit; and (c) stem cell survival. The stem cell population exhibited a trimodal distribution, with mean diameters of 5.7, 11.6 and 14.8 μm; a trimodal distribution has previously been identified in mice (Visser J et al, Exper Hematol Today, 21-27, 1977). At 40% fat in a human lumbar vertebra 3 section, approximately half the stem cells were located on, or very close to the edge, of fat cells in marrow sections. This agrees with the predicted distribution of distances between fat and stem cells obtained using a 3-D model with randomly distributed stem cells. At an air activity of 20 Bq m -3 (ie the UK average indoor radon concentration used by Richardson et al mentioned above) about 0.1 stem cells per person-year were hit and survived; at 100 Bq m -3 about 1 stem cell per person-year was hit and survived. Across the range of radon concentrations encountered in residential and underground miner exposures

  20. Electron field emission characteristics of graphene/carbon nanotubes hybrid field emitter

    International Nuclear Information System (INIS)

    Chen, Leifeng; He, Hong; Yu, Hua; Cao, Yiqi; Lei, Da; Menggen, QiQiGe; Wu, Chaoxing; Hu, Liqin

    2014-01-01

    The graphene (GP) and multi-walled carbon nanotubes (MCNTs) hybrid nanostructure emitter was constructed by a larger scale electrophoretic deposition (EPD) method. The field emission (FE) performance of the hybrid emitter is greatly improved compared with that of only GP or MCNTs emitter. The low turn-on electric field (EF), the low threshold EF and the reliability FE properties are obtained from the hybrid emitter. The better FE properties result from the improved electrical properties. For further enhancement FE of hybrids, Ag Nanoparticles (NPs) were decorated on the hybrids and FE characteristics were also studied. These studies indicate that we can use the hybrid nanostructure to improve conductivity and contact resistance, which results in enhancement of the FE properties

  1. Studies of emittance growth in the ATF

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1997-03-01

    Several different mechanisms of emittance growth in the Accelerator Test Facility (ATF) at KEK are investigated: the author calculates rise times of the fast beam-ion instability for the damping ring (DR), and discusses the emittance growth caused by coherent synchrotron radiation in the beam-transport line (BT), the effect of quadrupole wake fields in the injector linac, and, finally, a single-bunch head-tail ion effect that can occur in both the DR and the BT. A first attempt to measure the quadrupole wake on the real machine is also reported

  2. Standardization and estimation of gross alpha and beta activities for potable water samples in presence of TDS using TDCR based LSA (Hidex 300SL)

    International Nuclear Information System (INIS)

    Gupta, Anil; Lenka, P.; Sahoo, S.K.; Patra, A.C.; Jha, S.K.; Tripathi, R.M.

    2018-01-01

    Quality of water is important in environmental studies because of its daily use for human consumption and an important route of intake for various elements and radionuclides. Therefore radiological quality of drinking water must be ensured. The screening parameter to evaluate the radiological safety of potable water is by estimating gross alpha and gross beta activities with a limit of 0.5 Bq/l and 1 Bq/l respectively. These have been traditionally being done by radiochemical co-precipitation of alpha and beta emitters followed by counting by ZnS(Ag) counter for alpha and gas flow proportional counter for beta. Gross alpha estimation in water samples with high TDS by ZnS(Ag) is difficult and often leads to underestimation of result due to self-absorption of alpha within the residue. This study was carried out to standardize a method to provide rapid results by simultaneously estimating both gross alpha and gross beta activity in the presence of TDS with adequate sensitivity, minimum sample processing

  3. Chemically doped three-dimensional porous graphene monoliths for high-performance flexible field emitters.

    Science.gov (United States)

    Kim, Ho Young; Jeong, Sooyeon; Jeong, Seung Yol; Baeg, Kang-Jun; Han, Joong Tark; Jeong, Mun Seok; Lee, Geon-Woong; Jeong, Hee Jin

    2015-03-12

    Despite the recent progress in the fabrication of field emitters based on graphene nanosheets, their morphological and electrical properties, which affect their degree of field enhancement as well as the electron tunnelling barrier height, should be controlled to allow for better field-emission properties. Here we report a method that allows the synthesis of graphene-based emitters with a high field-enhancement factor and a low work function. The method involves forming monolithic three-dimensional (3D) graphene structures by freeze-drying of a highly concentrated graphene paste and subsequent work-function engineering by chemical doping. Graphene structures with vertically aligned edges were successfully fabricated by the freeze-drying process. Furthermore, their number density could be controlled by varying the composition of the graphene paste. Al- and Au-doped 3D graphene emitters were fabricated by introducing the corresponding dopant solutions into the graphene sheets. The resulting field-emission characteristics of the resulting emitters are discussed. The synthesized 3D graphene emitters were highly flexible, maintaining their field-emission properties even when bent at large angles. This is attributed to the high crystallinity and emitter density and good chemical stability of the 3D graphene emitters, as well as to the strong interactions between the 3D graphene emitters and the substrate.

  4. Generator-produced alpha-emitters

    International Nuclear Information System (INIS)

    Mirzadeh, S.

    1996-01-01

    This review briefly describes the nuclear characteristics and production parameters for 7.2-h 211 At, 60.6-min 212 Bi, 45.6-min 213 Bi, 11-d 233 Ra, and 20-h 255 Fm. These a-emitting radioisotopes are the subject of current interest for a-particle-mediated radioimmunotherapy

  5. Double-step annealing and ambient effects on phosphorus implanted emitters in silicon

    International Nuclear Information System (INIS)

    Koji, T.; Tseng, W.F.; Mayer, J.W.; Suganuma, T.

    1979-01-01

    Emitters of npn silicon bipolar transistors have been made by a phosphorus implantation at 50 keV P + to a dose of 1 x 10 16 cm -2 . This was followed by high temperature processes to reduce lattice disorder, to drive-in the phosphorus atoms, and to form oxide layers. The first process step was carried out by using single- and double-step anneals in various ambients (dry N 2 , dry 0 2 and steam) while the drive-in and oxidation steps were common for all structures. Electrical measurements on emitter/base leakage current, low frequency (popcorn) noise and current gain showed that the annealing ambient had a major influence. The transistors with implanted emitters annealed in a dry N 2 ambient are comparable to commercial ones with thermally-diffused emitters. Transmission electron microscopy observations on samples annealed in steam ambients revealed dislocations extending into the sidewall of the emitter/base junction. This sidewell penetration of dislocations is the main origin of the degradation of the emitter/base junction characteristics. (author)

  6. Emittance growth in the DARHT Axis-II Downstream Transport

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Jr., Carl August [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-14

    Using a particle-in-cell (PIC) code, we investigated the possibilities for emittance growth through the quadrupole magnets of the system used to transport the high-current electron beam from an induction accelerator to the bremsstrahlung converter target used for flash radiography. We found that even highly mismatched beams exhibited little emittance growth (< 6%), which we attribute to softening of their initial hard edge current distributions. We also used this PIC code to evaluate the accuracy of emittance measurements using a solenoid focal scan following the quadrupole magnets. If the beam is round after the solenoids, the simulations indicate that the measurement is highly accurate, but it is substantially inaccurate for elliptical beams

  7. Cadmium-emitter self-powered thermal neutron detector performance characterization & reactor power tracking capability experiments performed in ZED-2

    Energy Technology Data Exchange (ETDEWEB)

    LaFontaine, M.W., E-mail: physics@execulink.com [LaFontaine Consulting, Kitchener, Ontario (Canada); Zeller, M.B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Nielsen, K. [Royal Military College of Canada, SLOWPOKE-2 Reactor, Kingston, Ontario (Canada)

    2014-07-01

    Cadmium-emitter self-powered thermal neutron flux detectors (SPDs), are typically used for flux monitoring and control applications in low temperature, test reactors such as the SLOWPOKE-2. A collaborative program between Atomic Energy of Canada, academia (Royal Military College of Canada (RMCC)) and industry (LaFontaine Consulting) was initiated to characterize the incore performance of a typical Cd-emitter SPD; and to obtain a definitive measure of the capability of the detector to track changes in reactor power in real time. Prior to starting the experiment proper, Chalk River Laboratories' ZED-2 was operated at low power (5 watts nominal) to verify the predicted moderator critical height. Test measurements were then performed with the vertical center of the SPD emitter positioned at the vertical mid-plane of the ZED-2 reactor core. Measurements were taken with the SPD located at lattice position L0 (near center), and repeated at lattice position P0 (in D{sub 2}O reflector). An ionization chamber (part of the ZED-2 control instrumentation) monitored reactor power at a position located on the south side of the outside wall of the reactor's calandria. These experiments facilitated measurement of the absolute thermal neutron sensitivity of the subject Cd-emitter SPD, and validated the power tracking capability of said SPD. Procedural details of the experiments, data, calculations and associated graphs, are presented and discussed. (author)

  8. Field emission from optimized structure of carbon nanotube field emitter array

    International Nuclear Information System (INIS)

    Chouhan, V.; Noguchi, T.; Kato, S.

    2016-01-01

    The authors report a detail study on the emission properties of field emitter array (FEA) of micro-circular emitters of multiwall carbon nanotubes (CNTs). The FEAs were fabricated on patterned substrates prepared with an array of circular titanium (Ti) islands on titanium nitride coated tantalum substrates. CNTs were rooted into these Ti islands to prepare an array of circular emitters. The circular emitters were prepared in different diameters and pitches in order to optimize their structure for acquiring a high emission current. The pitch was varied from 0 to 600 μm, while a diameter of circular emitters was kept constant to be 50 μm in order to optimize a pitch. For diameter optimization, a diameter was changed from 50 to 200 μm while keeping a constant edge-to-edge distance of 150 μm between the circular emitters. The FEA with a diameter of 50 μm and a pitch of 120 μm was found to be the best to achieve an emission current of 47 mA corresponding to an effective current density of 30.5 A/cm"2 at 7 V/μm. The excellent emission current was attributed to good quality of CNT rooting into the substrate and optimized FEA structure, which provided a high electric field on a whole circular emitter of 50 μm and the best combination of the strong edge effect and CNT coverage. The experimental results were confirmed with computer simulation.

  9. Field emission from optimized structure of carbon nanotube field emitter array

    Energy Technology Data Exchange (ETDEWEB)

    Chouhan, V., E-mail: vchouhan@post.kek.jp, E-mail: vijaychouhan84@gmail.com [School of High Energy Accelerator, The Graduate University for Advanced Studies, Tsukuba 305-0801 (Japan); Noguchi, T. [High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan); Kato, S. [School of High Energy Accelerator, The Graduate University for Advanced Studies, Tsukuba 305-0801 (Japan); High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801 (Japan)

    2016-04-07

    The authors report a detail study on the emission properties of field emitter array (FEA) of micro-circular emitters of multiwall carbon nanotubes (CNTs). The FEAs were fabricated on patterned substrates prepared with an array of circular titanium (Ti) islands on titanium nitride coated tantalum substrates. CNTs were rooted into these Ti islands to prepare an array of circular emitters. The circular emitters were prepared in different diameters and pitches in order to optimize their structure for acquiring a high emission current. The pitch was varied from 0 to 600 μm, while a diameter of circular emitters was kept constant to be 50 μm in order to optimize a pitch. For diameter optimization, a diameter was changed from 50 to 200 μm while keeping a constant edge-to-edge distance of 150 μm between the circular emitters. The FEA with a diameter of 50 μm and a pitch of 120 μm was found to be the best to achieve an emission current of 47 mA corresponding to an effective current density of 30.5 A/cm{sup 2} at 7 V/μm. The excellent emission current was attributed to good quality of CNT rooting into the substrate and optimized FEA structure, which provided a high electric field on a whole circular emitter of 50 μm and the best combination of the strong edge effect and CNT coverage. The experimental results were confirmed with computer simulation.

  10. Calculating emittance for Gaussian and Non-Gaussian distributions by the method of correlations for slits

    International Nuclear Information System (INIS)

    Tan, Cheng-Yang; Fermilab

    2006-01-01

    One common way for measuring the emittance of an electron beam is with the slits method. The usual approach for analyzing the data is to calculate an emittance that is a subset of the parent emittance. This paper shows an alternative way by using the method of correlations which ties the parameters derived from the beamlets to the actual parameters of the parent emittance. For parent distributions that are Gaussian, this method yields exact results. For non-Gaussian beam distributions, this method yields an effective emittance that can serve as a yardstick for emittance comparisons

  11. Fabrication of multi-emitter array of CNT for enhancement of current density

    Energy Technology Data Exchange (ETDEWEB)

    Chouhan, Vijay, E-mail: vchouhan@post.kek.jp [Department of Accelerator Science, Graduate University for Advanced Studies, 1-1 Oho, Tsukuba, Ibaraki (Japan); Noguchi, Tsuneyuki [High Energy Accelerator Research Organization-KEK, 1-1 Oho, Tsukuba, Ibaraki (Japan); Kato, Shigeki [Department of Accelerator Science, Graduate University for Advanced Studies, 1-1 Oho, Tsukuba, Ibaraki (Japan); High Energy Accelerator Research Organization-KEK, 1-1 Oho, Tsukuba, Ibaraki (Japan)

    2011-11-11

    We studied and compared field emission properties of two kinds of emitters of randomly oriented multi-wall carbon nanotubes (MWNTs), viz. continuous film emitter (CFE) and multi-emitter array (MEA). The CFE has a continuous film of MWNTs while the MEA consists of many equidistant small circular emitters. Both types of emitters were prepared by dispersing MWNTs over a titanium (Ti) film (for CFEs) or Ti circular islands (for MEAs) deposited on tantalum (Ta) followed by rooting of MWNTs into the Ti film or the Ti islands at high temperature. Emission properties of both types of emitters were analyzed with changing their emission areas. In case of the CFEs, current density decreased with an increase in emission area whereas consistent current densities were achieved from MEAs with different emission areas. In other words, the total emission current was achieved in proportion to the emission area in the case of MEAs. Additionally a high current density of 22 A/cm{sup 2} was achieved at an electric field of 8 V/{mu}m from MEAs, which was far better than that obtained from CFEs. The high current density in MEAs was attributed to edge effect, in which higher emission current is achieved from the edge of film emitter. The results indicate that the field emission characteristics can be greatly improved if a cathode contains many small equidistant circular emitters instead of a continuous film. The outstanding stability of the CFE and the MEA has been demonstrated for 2100 and 1007 h, respectively.

  12. Emittance growth due to negative-mass instability above transition

    International Nuclear Information System (INIS)

    Ng, King-Yuen.

    1994-08-01

    Due to space-charge effect, there is a growth of bunch emittance across transition as a result of negative-mass instability. The models of growth at cutoff frequency and growth from high-frequency Schottky noise are reviewed. The difficulties of performing reliable simulations are discussed. An intuitive self-bunching model for estimating emittance growth is presented

  13. Experimental studies on coherent synchrotron radiation at an emittance exchange beam line

    Directory of Open Access Journals (Sweden)

    J. C. T. Thangaraj

    2012-11-01

    Full Text Available One of the goals of the Fermilab A0 photoinjector is to investigate experimentally the transverse to longitudinal emittance exchange (EEX principle. Coherent synchrotron radiation in the emittance exchange line could limit the performance of the emittance exchanger at short bunch lengths. In this paper, we present experimental and simulation studies of the coherent synchrotron radiation (CSR in the emittance exchange line at the A0 photoinjector. We report on time-resolved CSR studies using a skew-quadrupole technique. We also demonstrate the advantages of running the EEX with an energy-chirped beam.

  14. Analysis of emittance compensation and simulation results to photo-cathode RF gun

    CERN Document Server

    LiuShengGuang

    2002-01-01

    The emittance compensation technology will be used on the photo-cathode RF gun for Shanghai SDUV-FEL. The space charge force and its effect on electron beam transverse emittance in RF gun is studied, the principle of emittance compensation in phase-space is discussed. The authors have designed a compensation solenoid and calculated its magnetic field distribution. Its performance has been studied by the code PARMELA. A simulation result indicates that the normalized transverse RMS emittance for electron beam of 1.5 nC is 1.612 pi mm centre dot mrad, electron energy E = 5.71 MeV

  15. Very low recombination phosphorus emitters for high efficiency crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Ortega, P; Vetter, M; Bermejo, S; Alcubilla, R

    2008-01-01

    This work studies low recombination phosphorus emitters on c-Si. The emitters are fabricated by diffusion from solid sources and then passivated by thermal oxide yielding sheet resistances between 15 and 280 Ω/sq. Emitter saturation current densities lie in the 2.5–110 fA cm −2 range, leading to implicit open-circuit voltages between 674 and 725 mV. Bulk lifetime is limited by intrinsic recombination mechanisms. Surface recombination velocities between 80 and 300 cm s −1 have been obtained, appearing among the lowest reported in this range of emitter sheet resistances

  16. Large area gridded ionisation chamber and electrostatic precipitator and their application to low-level alpha-spectrometry of environmental air samples

    International Nuclear Information System (INIS)

    Hoetzl, H.; Winkler, R.

    1977-01-01

    A high-resolution, parallel plate Frisch grid ionization chamber with an efficient area of 3000 cm 2 , and a large area electrostatic precipitator were developed and applied to direct alpha spectrometry of air dust. Using an argon-methane mixture (P-10 gas) at atmospheric pressure the resolution of the detector system is 22 keV FWHM at 5 MeV. After sampling for one week and decay of short-lived natural activity, the sensitivity of the procedure for long-lived alpha emitters is about 0.1 fCi/m 3 taking 3 Σσ of background as the detection limit with 1000 min counting time. (author)

  17. Sources of variability in the determination by evaporation method of gross alpha activity in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Corbacho, J.A. [LARUEX, Caceres (Spain). Environmental Radioactivity Lab.

    2013-07-01

    Determining the gross alpha activity concentration of water samples is one way to screen for waters whose radionuclide content is so high that its consumption could imply surpassing the Total Indicative Dose as defined in European Directive 98/83/EC. One of the most commonly used methods to prepare the sources to measure gross alpha activity in water samples is desiccation. Its main advantages are the simplicity of the procedure, the low cost of source preparation, and the possibility of simultaneously determining the gross beta activity. The preparation of the source, the construction of the calibration curves, and the measurement procedure itself involve, however, various factors that may introduce sufficient variability into the results to significantly affect the screening process. We here identify the main sources of this variability, and propose specific procedures to follow in the desiccation process that will reduce the uncertainties, and ensure that the result is indeed representative of the sum of the activities of the alpha emitters present in the sample. (orig.)

  18. Origins of transverse emittance blow-up during the LHC energy tramp

    CERN Document Server

    Kuhn, M; Arduini, G; Kain, V; Schaumann, M; Tomas, R

    2014-01-01

    During LHC Run 1 about 30 % of the potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. Measurements indicated that the majority of the blow-up occurred during the energy ramp. Until the end of LHC Run 1 this emittance blow-up could not be eliminated. In this paper the measurements and observations of emittance growth through the ramp are summarized. Simulation results for growth due to Intra Beam Scattering will be shown and compared to measurements. A summary of investigations of other possible sources will be given and backed up with simulations where possible. Requirements for commissioning the LHC with beam in 2015 after Long Shutdown 1 to understand and control emittance blow-up will be listed.

  19. Orientation of the calcium channel beta relative to the alpha(12.2 subunit is critical for its regulation of channel activity.

    Directory of Open Access Journals (Sweden)

    Iuliia Vitko

    Full Text Available BACKGROUND: The Ca(vbeta subunits of high voltage-activated Ca(2+ channels control the trafficking and biophysical properties of the alpha(1 subunit. The Ca(vbeta-alpha(1 interaction site has been mapped by crystallographic studies. Nevertheless, how this interaction leads to channel regulation has not been determined. One hypothesis is that betas regulate channel gating by modulating movements of IS6. A key requirement for this direct-coupling model is that the linker connecting IS6 to the alpha-interaction domain (AID be a rigid structure. METHODOLOGY/PRINCIPAL FINDINGS: The present study tests this hypothesis by altering the flexibility and orientation of this region in alpha(12.2, then testing for Ca(vbeta regulation using whole cell patch clamp electrophysiology. Flexibility was induced by replacement of the middle six amino acids of the IS6-AID linker with glycine (PG6. This mutation abolished beta2a and beta3 subunits ability to shift the voltage dependence of activation and inactivation, and the ability of beta2a to produce non-inactivating currents. Orientation of Ca(vbeta with respect to alpha(12.2 was altered by deletion of 1, 2, or 3 amino acids from the IS6-AID linker (Bdel1, Bdel2, Bdel3, respectively. Again, the ability of Ca(vbeta subunits to regulate these biophysical properties were totally abolished in the Bdel1 and Bdel3 mutants. Functional regulation by Ca(vbeta subunits was rescued in the Bdel2 mutant, indicating that this part of the linker forms beta-sheet. The orientation of beta with respect to alpha was confirmed by the bimolecular fluorescence complementation assay. CONCLUSIONS/SIGNIFICANCE: These results show that the orientation of the Ca(vbeta subunit relative to the alpha(12.2 subunit is critical, and suggests additional points of contact between these subunits are required for Ca(vbeta to regulate channel activity.

  20. Schottky’s conjecture, field emitters, and the point charge model

    Directory of Open Access Journals (Sweden)

    Kevin L. Jensen

    2016-06-01

    Full Text Available A Point Charge Model of conical field emitters, in which the emitter is defined by an equipotential surface of judiciously placed charges over a planar conductor, is used to confirm Schottky’s conjecture that field enhancement factors are multiplicative for a small protrusion placed on top of a larger base structure. Importantly, it is shown that Schottky’s conjecture for conical / ellipsoidal field emitters remains unexpectedly valid even when the dimensions of the protrusion begin to approach the dimensions of the base structure. The model is analytic and therefore the methodology is extensible to other configurations.

  1. Positioning with stationary emitters in a two-dimensional space-time

    International Nuclear Information System (INIS)

    Coll, Bartolome; Ferrando, Joan Josep; Morales, Juan Antonio

    2006-01-01

    The basic elements of the relativistic positioning systems in a two-dimensional space-time have been introduced in a previous work [Phys. Rev. D 73, 084017 (2006)] where geodesic positioning systems, constituted by two geodesic emitters, have been considered in a flat space-time. Here, we want to show in what precise senses positioning systems allow to make relativistic gravimetry. For this purpose, we consider stationary positioning systems, constituted by two uniformly accelerated emitters separated by a constant distance, in two different situations: absence of gravitational field (Minkowski plane) and presence of a gravitational mass (Schwarzschild plane). The physical coordinate system constituted by the electromagnetic signals broadcasting the proper time of the emitters are the so called emission coordinates, and we show that, in such emission coordinates, the trajectories of the emitters in both situations, the absence and presence of a gravitational field, are identical. The interesting point is that, in spite of this fact, particular additional information on the system or on the user allows us not only to distinguish both space-times, but also to complete the dynamical description of emitters and user and even to measure the mass of the gravitational field. The precise information under which these dynamical and gravimetric results may be obtained is carefully pointed out

  2. Alpha Emitting Radionuclides and Radiopharmaceuticals for Therapy

    International Nuclear Information System (INIS)

    Chérel, Michel; Barbet, Jacques

    2013-01-01

    Today, cancer treatments mainly rely on surgery or external beam radiation to remove or destroy bulky tumors. Chemotherapy is given when tumours cannot be removed or when dissemination is suspected. However, these approaches cannot permanently treat all cancers and relapse occurs in up to 50% of the patients’ population. Radioimmunotherapy (RIT) and peptide receptor radionuclide therapy (PRRT) are effective against some disseminated and metastatic diseases, although they are rarely curative. Most preclinical and clinical developments in this field have involved electron-emitting radionuclides, particularly iodine-131, yttrium-90 and lutetium-177. The large range of the electrons emitted by these radionuclides reduces their efficacy against very small tumour cell clusters or isolated tumour cells present in residual disease and in many haematological tumours (leukaemia, myeloma). The range of alpha particles in biological tissues is very short, less than 0.1 mm, which makes alpha emitters theoretically ideal for treatment of such isolated tumour cells or micro-clusters of malignant cells. Thus, over the last decade, a growing interest for the use of alpha-emitting radionuclides has emerged. Research on targeted alpha therapy (TAT) began years ago in Nantes through cooperation between Subatech, a nuclear physics laboratory, CRCNA, a cancer research centre with a nuclear oncology team and ITU (Karlsruhe, Germany). CD138 was demonstrated as a potential target antigen for Multiple Myeloma, which is a target of huge clinical interest particularly suited for TAT because of the disseminated nature of the disease consisting primarily of isolated cells and small clusters of tumour cells mainly localized in the bone marrow. Thus anti-CD138 antibodies were labelled with bismuth-213 from actinium-225/bismuth-213 generators provided by ITU and used to target multiple myeloma cells. In vitro studies showed cell cycle arrest, synergism with chemotherapy and very little induction

  3. Laser Process for Selective Emitter Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    G. Poulain

    2012-01-01

    Full Text Available Selective emitter solar cells can provide a significant increase in conversion efficiency. However current approaches need many technological steps and alignment procedures. This paper reports on a preliminary attempt to reduce the number of processing steps and therefore the cost of selective emitter cells. In the developed procedure, a phosphorous glass covered with silicon nitride acts as the doping source. A laser is used to open locally the antireflection coating and at the same time achieve local phosphorus diffusion. In this process the standard chemical etching of the phosphorous glass is avoided. Sheet resistance variation from 100 Ω/sq to 40 Ω/sq is demonstrated with a nanosecond UV laser. Numerical simulation of the laser-matter interaction is discussed to understand the dopant diffusion efficiency. Preliminary solar cells results show a 0.5% improvement compared with a homogeneous emitter structure.

  4. Accurate estimation of the RMS emittance from single current amplifier data

    International Nuclear Information System (INIS)

    Stockli, Martin P.; Welton, R.F.; Keller, R.; Letchford, A.P.; Thomae, R.W.; Thomason, J.W.G.

    2002-01-01

    This paper presents the SCUBEEx rms emittance analysis, a self-consistent, unbiased elliptical exclusion method, which combines traditional data-reduction methods with statistical methods to obtain accurate estimates for the rms emittance. Rather than considering individual data, the method tracks the average current density outside a well-selected, variable boundary to separate the measured beam halo from the background. The average outside current density is assumed to be part of a uniform background and not part of the particle beam. Therefore the average outside current is subtracted from the data before evaluating the rms emittance within the boundary. As the boundary area is increased, the average outside current and the inside rms emittance form plateaus when all data containing part of the particle beam are inside the boundary. These plateaus mark the smallest acceptable exclusion boundary and provide unbiased estimates for the average background and the rms emittance. Small, trendless variations within the plateaus allow for determining the uncertainties of the estimates caused by variations of the measured background outside the smallest acceptable exclusion boundary. The robustness of the method is established with complementary variations of the exclusion boundary. This paper presents a detailed comparison between traditional data reduction methods and SCUBEEx by analyzing two complementary sets of emittance data obtained with a Lawrence Berkeley National Laboratory and an ISIS H - ion source

  5. Quantitative single-particle digital autoradiography with α-particle emitters for targeted radionuclide therapy using the iQID camera.

    Science.gov (United States)

    Miller, Brian W; Frost, Sofia H L; Frayo, Shani L; Kenoyer, Aimee L; Santos, Erlinda; Jones, Jon C; Green, Damian J; Hamlin, Donald K; Wilbur, D Scott; Fisher, Darrell R; Orozco, Johnnie J; Press, Oliver W; Pagel, John M; Sandmaier, Brenda M

    2015-07-01

    Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50-80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antibodies labeled with α emitters may thus inactivate targeted cells with minimal radiation damage to surrounding tissues. Tools are needed to visualize and quantify the radioactivity distribution and absorbed doses to targeted and nontargeted cells for accurate dosimetry of all treatment regimens utilizing α particles, including RIT and others (e.g., Ra-223), especially for organs and tumors with heterogeneous radionuclide distributions. The aim of this study was to evaluate and characterize a novel single-particle digital autoradiography imager, the ionizing-radiation quantum imaging detector (iQID) camera, for use in α-RIT experiments. The iQID camera is a scintillator-based radiation detection system that images and identifies charged-particle and gamma-ray/x-ray emissions spatially and temporally on an event-by-event basis. It employs CCD-CMOS cameras and high-performance computing hardware for real-time imaging and activity quantification of tissue sections, approaching cellular resolutions. In this work, the authors evaluated its characteristics for α-particle imaging, including measurements of intrinsic detector spatial resolutions and background count rates at various detector configurations and quantification of activity distributions. The technique was assessed for quantitative imaging of astatine-211 ((211)At) activity distributions in cryosections of murine and canine tissue samples. The highest spatial resolution was measured at ∼20 μm full width at half maximum and the α-particle background was measured at a rate as low as (2.6 ± 0.5) × 10(-4) cpm/cm(2) (40 mm diameter detector area). Simultaneous imaging of multiple tissue sections was

  6. Modulation characteristics of graphene-based thermal emitters

    Science.gov (United States)

    Mahlmeister, Nathan Howard; Lawton, Lorreta Maria; Luxmoore, Isaac John; Nash, Geoffrey Richard

    2016-01-01

    We have investigated the modulation characteristics of the emission from a graphene-based thermal emitter both experimentally and through simulations using finite element method modelling. Measurements were performed on devices containing square multilayer graphene emitting areas, with the devices driven by a pulsed DC drive current over a range of frequencies. Simulations show that the dominant heat path is from the emitter to the underlying substrate, and that the thermal resistance between the graphene and the substrate determines the modulation characteristics. This is confirmed by measurements made on devices in which the emitting area is encapsulated by hexagonal boron nitride.

  7. Relation between field energy and RMS emittance in intense particle beams

    International Nuclear Information System (INIS)

    Wangler, T.P.; Crandall, K.R.; Mills, R.S.; Reiser, M.

    1985-01-01

    An equation is presented for continuous beams with azimuthal symmetry and continuous linear focusing, which expresses a relationship between the rate of change for squared rms emittance and the rate of change for a quantity we call the nonlinear field energy. The nonlinear field energy depends on the shape of the charge distribution and corresponds to the residual field energy possessed by beams with nonuniform charge distributions. The equation can be integrated for the case of an rms matched beam to yield a formula for space-charge-induced emittance growth that we have tested numerically for a variety of initial distributions. The results provide a framework for discussing the scaling of rms emittance growth and an explanation for the well-established lower limit on output emittance. 15 refs., 4 figs

  8. Beam emittance of the Stony Brook Tandem-LINAC booster

    International Nuclear Information System (INIS)

    Scholldorf, A.H.

    1984-01-01

    This dissertation is primarily a study of the longitudinal and transverse beam emittance of the Stony Brook Heavy Ion Tandem LINAC Accelerator Facility, with a secondary emphasis on the beam dynamical design of two key elements of the system: a low energy double-drift buncher, and an achromatic double-90 0 LINAC injection system. A transverse emittance measuring system consisting of two translation stages controlled by stepper motors is described. Each stage carried a pair of beam defining slits mounted so that both horizontal and vertical emittances could be measured with only linear motion of the stage assembly. Beam currents were measured directly by a low-noise, high-sensitivity electrometer circuit integrated with the second slit-stage assembly. A mini-computer controlled the motors and acquired and displayed the data. Transverse emittance areas of beams of 12 C, 16 O, 32 S, and 58 Ni were measured at ion source extraction potential, after ion source acceleration, after tandem acceleration, and after LINAC acceleration. The results were analyzed in terms of source sputter-cone geometry, angle straggling in gas and foil strippers, and a variety of other factors

  9. Comparison between arc drops in ignited thermionic converters with and without ion reflections at the emitter

    International Nuclear Information System (INIS)

    Lundgren, L.

    1985-01-01

    The output performance of two thermionic energy converters is compared. One converter has a normal emitter, working with zero field at the emitter which is close to the optimum working point, and the other has a low work function emitter and ion reflection at the emitter. A simple model of the plasma and the sheaths shows that a converter working with a low work function emitter and ion reflections gives a worse performance than a similar converter with a normal emitter

  10. Probing the emitter site of Renilla luciferase using small organic molecules; an attempt to understand the molecular architecture of the emitter site.

    Science.gov (United States)

    Salehi, Farajollah; Emamzadeh, Rahman; Nazari, Mahboobeh; Rasa, Seyed Mohammad Mahdi

    2016-12-01

    Renilla luciferase is a sensitive enzyme and has wide applications in biotechnology such as drug screening. Previous studies have tried to show the catalytic residues, nevertheless, the accurate architecture and molecular behavior of its emitter site remains uncharacterized. In this study, the activity of Renilla luciferase, in the presence of two small organic molecules including dimethyl sulfoxide (DMSO) and isopropanol was considered and the structure was studied by circular dichroism (CD) and fluorescence spectroscopy. Moreover, the interaction of small organic molecules with the Renilla luciferase was studied using molecular dynamics simulations. Kinetics studies showed that at low concentration of DMSO (16.6-66mM) and isopropanol (19.3-76mM) the K m changed and a competitive inhibition pattern was observed. Moreover, spectroscopy studies reveled that the changes of activity of Renilla luciferase in the presence of low concentrations of small organic molecules was not associated with structural collapse or severe changes in the enzyme conformation. Molecular dynamics simulations indicated that DMSO and isopropanol, as probing molecules, were both able to bind to the emitter site and remained with the residues of the emitter site. Based on the probing data, the architecture of the emitter site in the "non-binding" model was proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Strong nonlinearity-induced correlations for counterpropagating photons scattering on a two-level emitter

    DEFF Research Database (Denmark)

    Nysteen, Anders; McCutcheon, Dara; Mørk, Jesper

    2015-01-01

    We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could be quanti......We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could...

  12. Study on the risk of late damage in humans after incorporation of the short-lived alpha emitter Ra-224

    International Nuclear Information System (INIS)

    Wick, R.R.; Nekolla, E.A.; Kellerer, A.M.; Goessner, W.

    2003-01-01

    An epidemiological study has been carried out at the GSF - National Research Center for Environment and Health - between 1948 and 1975, on 1460 ankylosing spondylitis (AS) patients. The aim of the study was to ascertain the late health effects suffered by these patients who had received repeated intravenous injections of the short lived α-emitter 224 Ra. These patients have been followed together with a control group of 1323 ankylosing spondylitis patients not treated with radioactive drugs and/or X-rays. Causes of death have been ascertained for 842 exposed patients and 861 controls by the end of 2002. In the exposed group there has been a total of 219 malignant diseases and 206 cases among the controls. In particular, we observed 15 cases of leukaemia in the exposure group and 8 cases of leukaemia in the control group. Further subclassification of the leukaemias demonstrated a high increase of myeloid leukaemia in the exposure group (9 cases obs. vs. 2.5 cases exp.), and out of these especially the acute myeloid leukaemias (6 cases observed vs. 1.6 expected), whereas in the control group the observed cases are within the expected range (3 myeloid leukaemias vs. 2.6 cases). Out of these 6 cases of myeloid leukaemia, 3 cases have been observed at doses comparable to those of the currently applied 224 Ra treatment with the preparation SpondylAT registered , in one case the 224 Ra-dose was the 0.6fold, in another case 1.6fold, whereas in one case the total dose could not be verified exactly. The enhanced leukaemia incidence in our exposed group is in line with results from animal experiments in mice having been injected with bone seeking α-emitters given at low dose rates. (orig.) [de

  13. Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

    International Nuclear Information System (INIS)

    Adams, Gregory P.

    2004-01-01

    The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively localized in vitro on tumor cells that expressed both antigens and were capable of effective tumor localization in in vivo studies

  14. Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Gregory P.

    2004-11-24

    The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively localized in vitro on tumor cells that expressed both antigens and were capable of effective tumor localization in in vivo studies.

  15. Emittance scans for CMS luminosity calibration in 2017

    CERN Document Server

    CMS Collaboration

    2018-01-01

    Emittance scans are short van der Meer type scans performed at the beginning and at the end of LHC fills. The beams are scanned against each other in X and Y planes in 7 displacement steps. These scans are used for LHC diagnostics and since 2017 for a cross check of the CMS luminosity calibration. An XY pair of scans takes around 3 minutes. The BRIL project provides to LHC three independent online luminosity measurement from the Pixel Luminosity Telescope (PLT), the Fast Beam Condition Monitor (BCM1F) and the Forward calorimeter (HF). The excellent performance of the BRIL detector front-ends, fast back-end electronics and CMS XDAQ based data processing and publication allow the use of emittance scans for linearity and stability studies of the luminometers. Emittance scans became a powerful tool and dramatically improved the understanding of the luminosity measurement during the year. Since each luminometer is independently calibrated in every scan the measurements are independent and ratios of luminometers ca...

  16. Low Emittance Gun Project based on Field Emission

    CERN Document Server

    Ganter, Romain; Dehler, M; Gobrecht, Jens; Gough, Chris; Ingold, Gerhard; Leemann, Simon C; Shing-Bruce-Li, Kevin; Paraliev, Martin; Pedrozzi, Marco; Raguin, Jean Yves; Rivkin, Leonid; Schlott, Volker; Sehr, Harald; Streun, Andreas; Wrulich, Albin F; Zelenika, Sasa

    2004-01-01

    The design of an electron gun capable of producing beam emittance one order of magnitude lower than current technology would reduce considerably the cost and size of a free electron laser emitting at 0.1nm. Field emitter arrays (FEAs) including a gate and a focusing layer are an attractive technology for such high brightness sources. Electrons are extracted from micrometric tips thanks to voltage pulses between gate and tips. The focusing layer should then reduce the initial divergence of each emitted beamlets. This FEA will be inserted in a high gradient diode configuration coupled with a radiofrequency structure. In the diode part very high electric field pulses (several hundreds of MV/m) will limit the degradation of emittance due to space charge effect. This first acceleration will be obtained with high voltage pulses (typically a megavolt in a few hundred of nanoseconds) synchronized with the low voltage pulses applied to the FEA (typically one hundred of volts in one nanosecond at frequency below kilohe...

  17. Control and Data Analysis for Emittance Measuring Devices

    CERN Document Server

    Hoffmann, T

    2001-01-01

    Due to the wide range of heavy ion beam intensities and energies in the GSI linac and the associated transfer channel to the synchrotron, several different types of emittance measurement systems have been established. Many common devices such as slit/grid or dipole-sweep systems are integrated into the GSI control system. Other systems like the single shot pepper pot method using CCD-cameras or stand-alone slit/grid set-ups are connected to personal computers. An overview is given about the various systems and their software integration. Main interest is directed on the software development for emittance front-end control and data analysis such as evaluation algorithms or graphical presentation of the results. In addition, special features for improved usability of the software such as data export, project databases and automatic report generation will be presented. An outlook on a unified evaluation procedure for all different types of emittance measurement is given.

  18. Superconducting wiggler magnets for beam-emittance damping rings

    CERN Document Server

    Schoerling, Daniel

    2012-01-01

    Ultra-low emittance beams with a high bunch charge are necessary for the luminosity performance of linear electron-positron colliders, such as the Compact Linear Collider (CLIC). An effective way to create ultra-low emittance beams with a high bunch charge is to use damping rings, or storage rings equipped with strong damping wiggler magnets. The remanent field of the permanent magnet materials and the ohmic losses in normal conductors limit the economically achievable pole field in accelerator magnets operated at around room temperature to below the magnetic saturation induction, which is 2.15 T for iron. In wiggler magnets, the pole field in the center of the gap is reduced further like the hyperbolic cosine of the ratio of the gap size and the period length multiplied by pi. Moreover, damping wiggler magnets require relatively large gaps because they have to accept the un-damped beam and to generate, at a small period length, a large magnetic flux density amplitude to effectively damp the beam emittance....

  19. Nanometer emittance ultralow charge beams from rf photoinjectors

    Directory of Open Access Journals (Sweden)

    R. K. Li

    2012-09-01

    Full Text Available In this paper we discuss the generation of a new class of high brightness relativistic electron beams, characterized by ultralow charge (0.1–1 pC and ultralow normalized emittance (<50  nm. These beams are created in rf photoinjectors when the laser is focused on the cathode to very small transverse sizes (<30  μm rms. In this regime, the charge density at the cathode approaches the limit set by the extraction electric field. By shaping the laser pulse to have a cigarlike aspect ratio (the longitudinal dimension much larger than the transverse dimension and a parabolic temporal profile, the resulting space charge dominated dynamics creates a uniformly filled ellipsoidal distribution and the emittance can be nearly preserved to its thermal value. We also present a new method, based on a variation of the pepper-pot technique, for single shot measurements of the ultralow emittances for this new class of beams.

  20. Graphene field emitters: A review of fabrication, characterization and properties

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Leifeng, E-mail: chlf@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yu, Hu; Zhong, Jiasong; Song, Lihui [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Jun, E-mail: wujun@hdu.edu.cn [Institute of Electron Device & Application, Hangzhou Dianzi University, Hangzhou, Zhejiang 310018 (China); Su, Weitao [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China)

    2017-06-15

    Highlights: • The preparation, characterization and field emission properties for Gs are reviewed. • The review provides an updated progress on design and construction of Gs field emitters. • The review offers fundamental insights into understanding and design of Gs emitters. • The review can broach the subject and inspire readers in field of Gs based emitters. - Abstract: Graphenes are beneficial to electrons field emission due to its high aspect ratio, high carrier density, the larger carrier mobility, excellent electrical and thermal conductivity, excellent mechanical strength and chemical stability. In recent years, graphene or reduced oxide graphene field emitters have been successfully constructed by various methods such as chemical vapor deposition, chemical exfoliation, electrophoretic deposition, screen-printing and chemical synthesis methods. Graphene emitters are tried to construct in distribution with some angles or vertical orientation with respect to the substrate surface. The vertical alignment of graphene sheets or edges arrays can facilitate efficient electron emission from the atomically thick sheets. Therefore they have even more a low turn-on and threshold-field electronic field, high field enhancement factor, high current stability and high luminance. In this review, we shortly survey and discuss recent research progress in graphene field emission properties with particular an emphasis on their preparing method, characterization and applications in devices especially for vertical graphene and single layer graphene, also including their challenges and future prospects.

  1. Studies and calculations of transverse emittance growth in proton storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.; Jackson, G.

    1989-01-01

    When high energy storage rings are used to collide beams of particles and antiparticles for high energy physics experiments, it is important to obtain as high an integrated luminosity as possible. Reduction of integrated luminosity can arise from several factors, in particular from growth of the transverse beam sizes (transverse emittances). We have studied the problem of transverse emittance growth in high energy storage rings caused by random dipole noise kicks to the beam. A theoretical formula for the emittance growth rate is derived, and agreement is obtained with experimental measurements where noise of known amplitude and power spectrum was deliberately injected into the Fermilab Tevatron, to kick the beam randomly. In the experiment, phase noise was introduced into the Tevatron rf system, and the measured dependence of horizontal emittance growth on phase noise amplitude is compared against the theoretically derived response. (orig.)

  2. Small-scale hot facility for reprocessing and alpha research

    International Nuclear Information System (INIS)

    Abdel-Rassoul, A.A.

    1976-01-01

    The experimental hot facility at Inchas is planned for research activities related to the decontamination of radioactive wastes, analytical chemistry of alpha emitters and chemical treatment of spent UO 2 -Mg fuel samples. The design concept permits safe handling of source materials with radioactivity levels up to 10000Ci. The laboratory includes a reception area, process hall, a number of research laboratories and other facilities for chemical and physical analysis, nuclear measurements and health physics control. The radioactive waste management plant allows for control and decontamination of intermediate- and low-level laboratory effluents. Fixation of radioactive residues will be carried out in the sludge immobilization plant. High-level fission-product waste liquors are subject to preconcentration and transformation to a glassy matrix before ultimate storage. (author)

  3. Emittances Studies at the Fermilab/NICADD Photoinjector Laboratory

    CERN Document Server

    Tikhoplav, Rodion; Melissinos, A C; Regis-Guy Piot, Philippe

    2005-01-01

    The Fermilab/NICADD photoinjector incorporates an L-band rf-gun capable of generating 1-10 nC bunches. The bunches are then accelerated to 16 MeV with a TESLA superconducting cavity. In the present paper we present parametric studies of transverse emittances and energy spread for a various operating points of the electron source (RF-gun E-field, laser length and spot size, and solenoid settings). We especially study the impact, on transverse emittance, of Gaussian and Plateau temporal distribution of the photocathode drive-laser.

  4. Simple emittance measurement of H- beams from a large plasma source

    International Nuclear Information System (INIS)

    Guharay, S.K.; Tsumori, K.; Hamabe, M.; Takeiri, Y.; Kaneko, O.; Kuroda, T.

    1996-03-01

    An emittance meter is developed using pepper-pot method. Kapton foils are used to detect intensity distributions of small beamlets at the 'image' plane of the pepper-pot. Emittance of H - beams from a large plasma source for the neutral beam injector of the Large Helical Device (LHD) has been measured. The normalized emittance (95%) of a 6 mA H - beam with emission current density of about 10 mA/cm 2 is ∼0.59 mm mrad. The present system is very simple, and it eliminates many complexities of the existing schemes. (author)

  5. Achievement of ultra-low emittance beam in the ATF damping ring

    CERN Document Server

    Honda, Y; Araki, S; Bane, Karl Leopold Freitag; Brachmann, A; Frisch, J; Fukuda, M; Hasegawa, K; Hayano, H; Hendrickson, L; Higashi, Y; Higo, T; Hirano, K; Hirose, T; Iida, K; Imai, T; Inoue, Y; Karataev, P; Kubo, K; Kurihara, Y; Kuriki, M; Kuroda, R; Kuroda, S; Luo, X; Matsuda, M; McCormick, D; Muto, T; Nakajima, K; Nelson, J; Nomura, M; Ohashi, A; Okugi, T; Omori, T; Ross, M; Sakai, H; Sakai, I; Sasao, N; Smith, S; Suzuki, T; Takano, M; Takashi, N; Taniguchi, T; Terunuma, N; Toge, N; Turner, J; Urakawa, J; Vogel, V; Wolski, A; Woodley, M; Yamazaki, I; Yamazaki, Y; Yocky, J; Young, A; Zimmermann, Frank

    2003-01-01

    We report on the smallest vertical emittance achieved in single-bunch-mode operation of the ATF. The emittances were measured with a laser-wire beam-profile monitor installed in the damping ring. The bunch length and the momentum spread of the beam were also recorded under the same conditions. The smallest vertical rms emittance measured is 4 pm in the limit of zero current. It increases by a factor of 1.5 for a bunch intensity of 10^10 electrons. There are no discrepancies between the measured data and the calculations of intra-beam scattering.

  6. Minimum emittance of isochronus rings for synchrotron light source

    CERN Document Server

    Shoji, Y

    1999-01-01

    Theoretically achievable minimum emittances of isochronus rings for synchrotron light source are calculated. The rings discussed in this paper consist of isochronus and achromatic bending cells, isochronus TBA (triple bend achromat) cells with negative dispersion, isochronus TBA cells with inverse bends or isochronus QBA (four bend achromat) cells. We show that the minimum emittances of these rings are roughly 2 or 3 times of those of the optimized non-isochronus rings.

  7. Emittance growth from rotated quadrupoles in heavy ion accelerators

    International Nuclear Information System (INIS)

    Barnard, J.J.

    1995-01-01

    We derive a set of moment equations which incorporates linear quadrupolar focusing and space-charge defocusing, in the presence of rotational misalignments of the quadrupoles about the direction of beam propagation. Although the usual beam emittance measured relative to fixed transverse x and y coordinate axes is not constant, a conserved emittance-like quantity has been found. Implications for alignment tolerances in accelerators for heavy-ion inertial fusion are discussed

  8. Ghost signals in Allison emittance scanners

    International Nuclear Information System (INIS)

    Stockli, Martin P.; Leitner, M.; Moehs, D.P.; Keller, R.; Welton, R.F.

    2004-01-01

    For over 20 years, Allison scanners have been used to measure emittances of low-energy ion beams. We show that scanning large trajectory angles produces ghost signals caused by the sampled beamlet impacting on an electric deflection plate. The ghost signal strength is proportional to the amount of beam entering the scanner. Depending on the ions, and their velocity, the ghost signals can have the opposite or the same polarity as the main beam signals. The ghost signals cause significant errors in the emittance estimates because they appear at large trajectory angles. These ghost signals often go undetected because they partly overlap with the real signals, are mostly below the 1% level, and often hide in the noise. A simple deflection plate modification is shown to reduce the ghost signal strength by over 99%

  9. Ghost Signals In Allison Emittance Scanners

    International Nuclear Information System (INIS)

    Stockli, Martin P.; Leitner, M.; Keller, R.; Moehs, D.P.; Welton, R. F.

    2005-01-01

    For over 20 years, Allison scanners have been used to measure emittances of low-energy ion beams. We show that scanning large trajectory angles produces ghost signals caused by the sampled beamlet impacting on an electric deflection plate. The ghost signal strength is proportional to the amount of beam entering the scanner. Depending on the ions, and their velocity, the ghost signals can have the opposite or the same polarity as the main beam signals. The ghost signals cause significant errors in the emittance estimates because they appear at large trajectory angles. These ghost signals often go undetected because they partly overlap with the real signals, are mostly below the 1% level, and often hide in the noise. A simple deflection plate modification is shown to reduce the ghost signal strength by over 99%

  10. Computing Eigen-Emittances from Tracking Data

    Energy Technology Data Exchange (ETDEWEB)

    Alexahin, Y. [Fermilab

    2014-09-18

    In a strongly nonlinear system the particle distribution in the phase space may develop long tails which contribution to the covariance (sigma) matrix should be suppressed for a correct estimate of the beam emittance. A method is offered based on Gaussian approximation of the original particle distribution in the phase space (Klimontovich distribution) which leads to an equation for the sigma matrix which provides efficient suppression of the tails and cannot be obtained by introducing weights. This equation is easily solved by iterations in the multi-dimensional case. It is also shown how the eigen-emittances and coupled optics functions can be retrieved from the sigma matrix in a strongly coupled system. Finally, the developed algorithm is applied to 6D ionization cooling of muons in HFOFO channel.

  11. Optical characterization of OLED emitter properties by radiation pattern analyses

    Energy Technology Data Exchange (ETDEWEB)

    Flaemmich, Michael

    2011-09-08

    Researches in both, academia and industry are investigating optical loss channels in OLED layered systems by means of optical simulation tools in order to derive promising concepts for a further enhancement of the overall device performance. Besides other factors, the prospects of success of such optimization strategies rely severely on the credibility of the optical input data. The present thesis provides a guideline to measure the active optical properties of OLED emitter materials in situ by radiation pattern analyses. Reliable and widely applicable methods are introduced to determine the internal electroluminescence spectrum, the profile of the emission zone, the dipole emitter orientation, and the internal luminescence quantum efficiency of emissive materials from the optical far field emission of OLEDs in electrical operation. The proposed characterization procedures are applied to sets of OLEDs containing both, fluorescent polymeric materials as well as phosphorescent small-molecular emitters, respectively. On the one hand, quite expected results are obtained. On the other hand, several novel and truly surprising results are found. Most importantly, this thesis contains the first report of a non-isotropic, mainly parallel emitter orientation in a phosphorescent small-molecular guest-host system (Ir(MDQ)2(acac) in a-NPD). Due to the latter result, emitter orientation based optimization of phosphorescent OLEDs seems to be within reach. Since parallel dipoles emit preferably into air, the utilization of smart emissive materials with advantageous molecular orientation is capable to boost the efficiency of phosphorescent OLEDs by 50%. Materials design, the influence of the matrix material and the substrate, as well as film deposition conditions are just a few parameters that need to be studied further in order to exploit the huge potential of the dipole emitter orientation in phosphorescent OLEDs.

  12. Sub-nanometer emittance monitor for high brightness synchrotron radiation source

    International Nuclear Information System (INIS)

    Nakajima, K.

    1991-01-01

    Method of measuring a very small beam emittance in electron storage rings is presented. The monitor can sense an intrinsic emittance of beam particles by detecting the angular distribution of Compton scatterings of laser photons on beam electrons. It is possible to achieve measurement resolution smaller than 10 -9 m-rad without difficulty. (author)

  13. Normal spectral emittance of Inconel 718 aeronautical alloy coated with yttria stabilized zirconia films

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Campo, L. del [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.es [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Emittance of Inconel 718 coated with plasma sprayed yttria stabilized zirconia. Black-Right-Pointing-Pointer The coating is opaque for {lambda} > 9 {mu}m and semi-transparent for {lambda} < 9 {mu}m. Black-Right-Pointing-Pointer In the semi-transparent region the emittance decreases with coating thickness. Black-Right-Pointing-Pointer 300 {mu}m thick coatings are still semi-transparent. Black-Right-Pointing-Pointer In the opaque region the surface roughness determines the emittance level. - Abstract: Knowledge of the radiative behaviour of the yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) is needed to perform radiative heat transfer calculations in industrial applications. In this paper, normal spectral emittance experimental data of atmospheric plasma sprayed (PS) YSZ films layered on Inconel 718 substrates are shown. The spectral emittance was measured between 2.5 and 22 {mu}m on samples with film thicknesses ranging from 20 to 280 {mu}m. The samples were heated in a controlled environment, and the emittance was measured for several temperatures between 330 and 730 Degree-Sign C. The dependence of the spectral emittance with film thickness, surface roughness and temperature has been studied and compared with the available results for YSZ TBCs obtained by electron-beam physical vapour deposition. The PS-TBC samples show a Christiansen point at {lambda} = 12.8 {mu}m. The films are semi-transparent for {lambda} < 9 {mu}m, and opaque for {lambda} > 9 {mu}m. In the semi-transparent region, the contribution of the radiation emitted by the Inconel 718 substrate to the global emittance of the samples is analysed. In addition, the influence of the roughness in the emittance values in the opaque spectral region is discussed. Finally, the total normal emittance is obtained as a function of the TBC thickness.

  14. The emittance of high current heavy ion beams

    International Nuclear Information System (INIS)

    White, N.R.; Devaney, A.S.

    1989-01-01

    Ion implantation is the main application for high current heavy ion beams. Transfer ratio is defined as the ratio of the total ion current leaving the ion source to the current delivered to the endstation. This ratio is monitored and logged and its importance is explained. It is also affected by other factors, such as the isotopic and molecular composition of the total ion beam. The transfer ratio reveals the fraction of ions which are intercepted by parts of the beamline system. The effects of these ions are discussed in two categories: processing purity and reliability. In discussing the emittance of ribbon beams, the two orthogonal planes are usually considered separately. Longitudinal emittance is determined by slot length and by plasma ion temperature. It has already been revealed that the longitudinal divergence of the beams from BF3 is perhaps double that of the beam from arsenic vapour or argon, at the same total perveance from the ion source. This poses the question: why is the ion temperature higher for BF3 than for As or Ar? The transverse emittance is in practical terms dominated by the divergence. It is the most fruitful area for improvement in most real-world systems. There is an intrinsic divergence arising from initial ion energies within the plasma, and there is emittance growth that can occur as a result of aberration in the beam extraction optics. (N.K.)

  15. Emittance control and RF bunch compression in the NSRRC photoinjector

    International Nuclear Information System (INIS)

    Lau, W.K.; Hung, S.B.; Lee, A.P.; Chou, C.S.; Huang, N.Y.

    2011-01-01

    The high-brightness photoinjector being constructed at the National Synchrotron Radiation Research Center is for testing new accelerator and light-source concepts. It is the so-called split photoinjector configuration in which a short solenoid magnet is used for emittance compensation. The UV-drive laser pulses are also shaped to produce uniform cylindrical bunches for further reduction of beam emittance. However, limited by the available power from our microwave power system, the nominal accelerating gradient in the S-band booster linac is set at 18 MV/m. A simulation study with PARMELA shows that the linac operating at this gradient fails to freeze the electron beam emittance at low value. A background solenoid magnetic field is applied for beam emittance control in the linac during acceleration. A satisfactory result that meets our preliminary goal has been achieved with the solenoid magnetic field strength at 0.1 T. RF bunch compression as a means to achieve the required beam brightness for high-gain free-electron laser experiments is also examined. The reduction of bunch length to a few hundred femtoseconds can be obtained.

  16. Benchmarking of measurement and simulation of transverse rms-emittance growth

    Directory of Open Access Journals (Sweden)

    L. Groening

    2008-09-01

    Full Text Available Transverse emittance growth along the Alvarez drift tube linac (DTL section is a major concern with respect to the preservation of beam quality of high current beams at the GSI UNILAC. In order to define measures to reduce this growth, appropriate tools to simulate the beam dynamics are indispensable. This paper is about the benchmarking of three beam dynamics simulation codes, i.e. DYNAMION, PARMILA, and PARTRAN against systematic measurements of beam emittances for different transverse phase advances along the DTL. Special emphasis is put on the modeling of the initial distribution for the simulations. The concept of rms equivalence is expanded from full intensity to fractions of less than 100% of the beam. The experimental setup, data reduction, preparation of the simulations, and the evaluation of the simulations are described. In the experiments and in the simulations, a minimum of the rms-emittance growth was observed at zero current phase advances of about 60°. In general, good agreement was found between simulations and experiment for the mean values of horizontal and vertical emittances at the DTL exit.

  17. High efficiency and stable white OLED using a single emitter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian [Arizona State Univ., Tempe, AZ (United States). School of Mechanical, Aerospace, Chemical and Materials Engineering

    2016-01-18

    The ultimate objective of this project was to demonstrate an efficient and stable white OLED using a single emitter on a planar glass substrate. The focus of the project is on the development of efficient and stable square planar phosphorescent emitters and evaluation of such class of materials in the device settings. Key challenges included improving the emission efficiency of molecular dopants and excimers, controlling emission color of emitters and their excimers, and improving optical and electrical stability of emissive dopants. At the end of this research program, the PI has made enough progress to demonstrate the potential of excimer-based white OLED as a cost-effective solution for WOLED panel in the solid state lighting applications.

  18. Beam emittance reduction during operation of Indus-2

    Energy Technology Data Exchange (ETDEWEB)

    Fakhri, Ali Akbar, E-mail: fakhri@rrcat.gov.in; Kant, Pradeep; Ghodke, A. D.; Singh, Gurnam [Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2015-11-15

    Indus-2 storage ring is a 2.5 GeV third generation synchrotron radiation source. This source was commissioned using a moderate optics. Beam injection was accomplished using an off momentum electron beam to avoid difficulties faced in storage of beam at 550 MeV. The injection procedure and relevant beam dynamical studies are discussed. The switch over from the moderate optics to low emittance optics is done at 2.5 GeV after storing the electron beam. The procedure evolved to reduce the beam emittance and its implementation during the operation is discussed.

  19. Nanodiamonds with photostable, sub-gigahertz linewidth quantum emitters

    Directory of Open Access Journals (Sweden)

    Toan Trong Tran

    2017-11-01

    Full Text Available Single-photon emitters with narrow linewidths are highly sought after for applications in quantum information processing and quantum communications. In this letter, we report on a bright, highly polarized near infrared single photon emitter embedded in diamond nanocrystals with a narrow, sub-GHz optical linewidth at 10 K. The observed zero-phonon line at ∼780 nm is optically stable under low power excitation and blue shifts as the excitation power increases. Our results highlight the prospect for using new near infrared color centers in nanodiamonds for quantum applications.

  20. Nanodiamonds with photostable, sub-gigahertz linewidth quantum emitters

    Science.gov (United States)

    Tran, Toan Trong; Kianinia, Mehran; Bray, Kerem; Kim, Sejeong; Xu, Zai-Quan; Gentle, Angus; Sontheimer, Bernd; Bradac, Carlo; Aharonovich, Igor

    2017-11-01

    Single-photon emitters with narrow linewidths are highly sought after for applications in quantum information processing and quantum communications. In this letter, we report on a bright, highly polarized near infrared single photon emitter embedded in diamond nanocrystals with a narrow, sub-GHz optical linewidth at 10 K. The observed zero-phonon line at ˜780 nm is optically stable under low power excitation and blue shifts as the excitation power increases. Our results highlight the prospect for using new near infrared color centers in nanodiamonds for quantum applications.

  1. Room-temperature deposition of diamond-like carbon field emitter on flexible substrates

    International Nuclear Information System (INIS)

    Chen, H.; Iliev, M.N.; Liu, J.R.; Ma, K.B.; Chu, W.-K.; Badi, N.; Bensaoula, A.; Svedberg, E.B.

    2006-01-01

    Room-temperature fabrication of diamond-like carbon electron field emitters on flexible polyimide substrate is reported. These thin film field emitters are made using an Ar gas cluster ion beam assisted C 6 vapor deposition method. The bond structure of the as-deposited diamond-like carbon film was studied using Raman spectroscopy. The field emission characteristics of the deposited films were also measured. Electron current densities over 15 mA/cm 2 have been recorded under an electrical field of about 65 V/μm. These diamond-like carbon field emitters are easy and inexpensive to fabricate. The results are promising for flexible field-emission fabrication without the need of complex patterning and tip shaping as compared to the Spindt-type field emitters

  2. DC-SC Photoinjector with Low Emittance at Peking University

    CERN Document Server

    Xiang Rong; Hao, J; Huang, Senlin; Lu Xiang Yang; Quan, Shengwen; Zhang, Baocheng; Zhao, Kui

    2005-01-01

    High average power Free Electron Lasers require the high quality electron beams with the low emittance and the sub-picosecond bunches. The design of DC-SC photoinjector, directly combining a DC photoinjector with an SRF cavity, can produce high average current beam with moderate bunch charge and high duty factor. Because of the DC gun, the emittance increases quickly at the beginning, so a carefully design is needed to control that. In this paper, the simulation of an upgraded design has been done to lower the normalized emittance below 1.5mm·mrad. The photoinjector consists of a DC gap and a 2+1/2-cell SRF cavity, and it is designed to produce 4.2 MeV electron beams at 100pC bunch charge and 81.25MHz repetition rate (8 mA average current).

  3. RF emittance in a low energy electron linear accelerator

    Science.gov (United States)

    Sanaye Hajari, Sh.; Haghtalab, S.; Shaker, H.; Kelisani, M. Dayyani

    2018-04-01

    Transverse beam dynamics of an 8 MeV low current (10 mA) S-band traveling wave electron linear accelerator has been studied and optimized. The main issue is to limit the beam emittance, mainly induced by the transverse RF forces. The linac is being constructed at Institute for Research in Fundamental Science (IPM), Tehran Iran Labeled as Iran's First Linac, nearly all components of this accelerator are designed and constructed within the country. This paper discusses the RF coupler induced field asymmetry and the corresponding emittance at different focusing levels, introduces a detailed beam dynamics design of a solenoid focusing channel aiming to reduce the emittance growth and studies the solenoid misalignment tolerances. In addition it has been demonstrated that a prebuncher cavity with appropriate parameters can help improving the beam quality in the transverse plane.

  4. Procedure to carry out leakage test in beta radiation sealed sources emitters of 90Sr/90Y

    International Nuclear Information System (INIS)

    Alvarez R, J. T.

    2010-09-01

    In the alpha-beta room of the Secondary Laboratory of Dosimetric Calibration of the Metrology Department of Ionizing Radiations ophthalmic applicators are calibrated in absorbed dose terms in water D w ; these applicators, basically are emitter sealed sources of pure beta radiation of 90 Sr / 90 Y. Concretely, the laboratory quality system indicates to use the established procedure for the calibration of these sources, which establishes the requirement of to carry out a leakage test, before to calibrate the source. However, in the Laboratory leakage test certificates sent by specialized companies in radiological protection services have been received, in which are used gamma spectrometry equipment s for beta radiation leakage tests, since it is not reliable to detect pure beta radiation with a scintillating detector with NaI crystal, (because it could detect the braking radiation produced in the detector). Therefore the Laboratory has had to verify the results of the tests with a correct technique, with the purpose of determining the presence of sources with their altered integrity and radioactive material leakage. The objective of this work is to describe a technique for beta activity measurement - of the standard ISO 7503, part 1 (1988) - and its application with a detector Gm plane (type pankage) in the realization of leakage tests in emitter sources of pure beta radiation, inside the mark of quality assurance indicated by the report ICRU 76. (Author)

  5. Calculations of emittance and damping time effects in the SLC damping rings

    International Nuclear Information System (INIS)

    Limberg, T.; Moshammer, H.; Raubenheimer, T.; Spencer, J.; Siemann, R.

    1992-03-01

    In a recent NDR machine experiment the transverse emittance was studied as a function of store time and tune. To explain the observed transverse emittance damping time constants, the magnetic measurement data of the longitudinal field of the bending magnets had to be taken into account. The variation of the transverse emittances with tune due to misalignments and the associated anomalous dispersion is studied as well as the effect of synchrobetatron coupling due to dispersion in the RF cavities

  6. Overcoming correlation fluctuations in two-photon interference experiments with differently bright and independently blinking remote quantum emitters

    Science.gov (United States)

    Weber, Jonas H.; Kettler, Jan; Vural, Hüseyin; Müller, Markus; Maisch, Julian; Jetter, Michael; Portalupi, Simone L.; Michler, Peter

    2018-05-01

    As a fundamental building block for quantum computation and communication protocols, the correct verification of the two-photon interference (TPI) contrast between two independent quantum light sources is of utmost importance. Here, we experimentally demonstrate how frequently present blinking dynamics and changes in emitter brightness critically affect the Hong-Ou-Mandel-type (HOM) correlation histograms of remote TPI experiments measured via the commonly utilized setup configuration. We further exploit this qualitative and quantitative explanation of the observed correlation dynamics to establish an alternative interferometer configuration, which is overcoming the discussed temporal fluctuations, giving rise to an error-free determination of the remote TPI visibility. We prove full knowledge of the obtained correlation by reproducing the measured correlation statistics via Monte Carlo simulations. As an exemplary system, we make use of two pairs of remote semiconductor quantum dots; however, the same conclusions apply for TPI experiments with flying qubits from any kind of remote solid-state quantum emitters.

  7. Highly flexible and robust N-doped SiC nanoneedle field emitters

    KAUST Repository

    Chen, Shanliang

    2015-01-23

    Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm-1, 1.55 V μm-1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. © 2015 Nature Publishing Group All rights reserved.

  8. Optimization of oxidation processes to improve crystalline silicon solar cell emitters

    Directory of Open Access Journals (Sweden)

    L. Shen

    2014-02-01

    Full Text Available Control of the oxidation process is one key issue in producing high-quality emitters for crystalline silicon solar cells. In this paper, the oxidation parameters of pre-oxidation time, oxygen concentration during pre-oxidation and pre-deposition and drive-in time were optimized by using orthogonal experiments. By analyzing experimental measurements of short-circuit current, open circuit voltage, series resistance and solar cell efficiency in solar cells with different sheet resistances which were produced by using different diffusion processes, we inferred that an emitter with a sheet resistance of approximately 70 Ω/□ performed best under the existing standard solar cell process. Further investigations were conducted on emitters with sheet resistances of approximately 70 Ω/□ that were obtained from different preparation processes. The results indicate that emitters with surface phosphorus concentrations between 4.96 × 1020 cm−3 and 7.78 × 1020 cm−3 and with junction depths between 0.46 μm and 0.55 μm possessed the best quality. With no extra processing, the final preparation of the crystalline silicon solar cell efficiency can reach 18.41%, which is an increase of 0.4%abs compared to conventional emitters with 50 Ω/□ sheet resistance.

  9. Highly flexible and robust N-doped SiC nanoneedle field emitters

    KAUST Repository

    Chen, Shanliang; Ying, Pengzhan; Wang, Lin; Wei, Guodong; Gao, Fengmei; Zheng, Jinju; Shang, Minhui; Yang, Zuobao; Yang, Weiyou; Wu, Tao

    2015-01-01

    Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm-1, 1.55 V μm-1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. © 2015 Nature Publishing Group All rights reserved.

  10. Investigations on the transverse phase space at a photo injector for minimized emittance

    Energy Technology Data Exchange (ETDEWEB)

    Miltchev, V.

    2006-08-15

    Radio frequency photoinjectors are electron sources able to generate beams of extremely high brightness, which are applicable to linac driven Free Electron Lasers (FEL). Because of the high phase space density, the dynamics of the electron beam is dominated by space charge interactions between the particles. This thesis studies the transverse phase space of space charge dominated electron beams produced by the Photo Injector Test Facility in Zeuthen (PITZ). The operation conditions for minimizing the transverse emittance are studied experimentally, theoretically and in simulations. The influence of the longitudinal profile of the driving UV laser pulse on the transverse emittance is investigated. Emphasis is placed on the experimental study of the emittance as a function of different machine parameters like the laser beam spot size, the amplitude of the focusing magnetic field, the rf phase and the electron bunch charge. First investigations on the thermal emittance for Cs{sub 2}Te photocathodes under rf operating conditions are presented. Measurements of the thermal emittance scaling with the photocathode laser spot size are analyzed. The significance of the applied rf field in the emittance formation process is discussed. (orig.)

  11. Investigations on the transverse phase space at a photo injector for minimized emittance

    International Nuclear Information System (INIS)

    Miltchev, V.

    2006-08-01

    Radio frequency photoinjectors are electron sources able to generate beams of extremely high brightness, which are applicable to linac driven Free Electron Lasers (FEL). Because of the high phase space density, the dynamics of the electron beam is dominated by space charge interactions between the particles. This thesis studies the transverse phase space of space charge dominated electron beams produced by the Photo Injector Test Facility in Zeuthen (PITZ). The operation conditions for minimizing the transverse emittance are studied experimentally, theoretically and in simulations. The influence of the longitudinal profile of the driving UV laser pulse on the transverse emittance is investigated. Emphasis is placed on the experimental study of the emittance as a function of different machine parameters like the laser beam spot size, the amplitude of the focusing magnetic field, the rf phase and the electron bunch charge. First investigations on the thermal emittance for Cs 2 Te photocathodes under rf operating conditions are presented. Measurements of the thermal emittance scaling with the photocathode laser spot size are analyzed. The significance of the applied rf field in the emittance formation process is discussed. (orig.)

  12. Emittance studies of the BNL/SLAC/UCLA 1.6 cell photocathode rf gun

    International Nuclear Information System (INIS)

    Palmer, D.T.; Miller, R.H.; Wang, X.J.

    1997-01-01

    The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 micros. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, ε o , of the copper cathode has been measured

  13. New Method for Determination of Electrically Inactive Phosphorus in n-type Emitters

    OpenAIRE

    Steyer, Michael; Dastgheib-Shirazi, Amir; Hahn, Giso; Terheiden, Barbara

    2015-01-01

    The precise knowledge of the amount and the location in depth of inactive phosphorus in an n-type emitter is still a challenge. As a new approach, we determine the total amount of phosphorus (P dose) in the emitter stepwise in dependence of etching depth with the characterization tool ICP-OES. A comparison of the data with the electrically active P concentration profile measured by ECV allows to determine in which depths electrically inactive phosphorus is present. For a highly doped emitter,...

  14. Emittance compensation with dynamically optimized photoelectron beam profiles

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, J.B. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States)]. E-mail: rosen@physics.ucla.edu; Cook, A.M. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); England, R.J. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); Dunning, M. [Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90095 (United States); Anderson, S.G. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Ferrario, Massimo [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionale di Frascati, Via E. Fermi 41, Frascati, Rome (Italy)

    2006-02-01

    Much of the theory and experimentation concerning creation of a high-brightness electron beam from a photocathode, and then applying emittance compensation techniques, assumes that one must strive for a uniform density electron beam, having a cylindrical shape. On the other hand, this shape has large nonlinearities in the space-charge field profiles near the beam's longitudinal extrema. These nonlinearities are known to produce both transverse and longitudinal emittance growth. On the other hand, it has recently been shown by Luiten that by illuminating the cathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped bunch is dynamically formed, which then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage to the standard emittance compensation scenario that is implemented in most recent photoinjectors. It is seen that the two processes are compatible, with simulations indicating a very high brightness beam can be obtained. The robustness of this scheme to systematic errors is examined. Prospects for experimental tests of this scheme are discussed.

  15. Emittance compensation with dynamically optimized photoelectron beam profiles

    International Nuclear Information System (INIS)

    Rosenzweig, J.B.; Cook, A.M.; England, R.J.; Dunning, M.; Anderson, S.G.; Ferrario, Massimo

    2006-01-01

    Much of the theory and experimentation concerning creation of a high-brightness electron beam from a photocathode, and then applying emittance compensation techniques, assumes that one must strive for a uniform density electron beam, having a cylindrical shape. On the other hand, this shape has large nonlinearities in the space-charge field profiles near the beam's longitudinal extrema. These nonlinearities are known to produce both transverse and longitudinal emittance growth. On the other hand, it has recently been shown by Luiten that by illuminating the cathode with an ultra-short laser pulse of appropriate transverse profile, a uniform density, ellipsoidally shaped bunch is dynamically formed, which then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage to the standard emittance compensation scenario that is implemented in most recent photoinjectors. It is seen that the two processes are compatible, with simulations indicating a very high brightness beam can be obtained. The robustness of this scheme to systematic errors is examined. Prospects for experimental tests of this scheme are discussed

  16. Measuring emittances and sigma matrices

    International Nuclear Information System (INIS)

    Rees, J.; Rivkin, L.

    1984-03-01

    The method used for measuring emittance at the SLAC Linac and the linear collider damping ring is described. The basis of the method is derived using one two-by-two matrix to specify the state of the input beam (sigma matrix) and another to describe the lens-drift transport system (R-matrix)

  17. Generation of low-emittance electron beams in electrostatic accelerators for FEL applications

    Science.gov (United States)

    Teng, Chen; Elias, Luis R.

    1995-02-01

    This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations.

  18. Generation of low-emittance electron beams in electrostatic accelerators for FEL applications

    International Nuclear Information System (INIS)

    Chen Teng; Central Florida Univ., Orlando, FL; Elias, L.R. R.; Central Florida Univ., Orlando, FL

    1995-01-01

    This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations. ((orig.))

  19. Generation of low-emittance electron beams in electrostatic accelerators for FEL applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen Teng [University of Central Florida, Orlando, FL (United States). Center for Research in Electro-Optics and Lasers (CREOL)]|[Central Florida Univ., Orlando, FL (United States). Dept. of Physics; Elias, L.R. R. [University of Central Florida, Orlando, FL (United States). Center for Research in Electro-Optics and Lasers (CREOL)]|[Central Florida Univ., Orlando, FL (United States). Dept. of Physics

    1995-01-30

    This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations. ((orig.))

  20. Measurements of. alpha. -emitting plutonium and americium in the intertidal sands of west Cumbria, UK

    Energy Technology Data Exchange (ETDEWEB)

    Eakins, J.D.; Morgan, A.; Baston, G.M.N.; Pratley, F.W.; Strange, L.P.; Burton, P.J. (UKAEA Harwell Lab. (UK). Environmental and Medical Science Div.)

    1990-01-01

    Samples of surface sand and sand cores were collected from intertidal regions of west Cumbria between Silloth and Walney Island (including the Duddon Estuary) between 1982 and 1984 and analysed for {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am. Generally, more than 95% of the {alpha}-emitting transuranic nuclides were associated with the sand and less than 5% with entrained silt. The greatest concentrations of both plutonium and americium were found at Braystones. Concentrations declined with distance from the Sellafield Works. The largest actinide deposits occurred at Drigg (320 and 720 kBq m{sup -2} of {sup 239+240}Pu and {sup 241}Am respectively). The integrated deposits in intertidal sand between Silloth and Walney Island were about 4.2 and 7.0 TBq respectively, which represent about 1% of the total {alpha}-emitting activity discharged to sea from Sellafield Works up to 1982. The corresponding value for the Duddon Estuary is about 0.3%. Only on beaches close to Sellafield did levels of man-made {alpha}-emitters exceed those of natural {alpha}-emitting nuclides. The radiological consequences of the intertidal inventory of plutonium and americium are shown to be very small and much less than from the seafood pathway. (author).

  1. Global determination of alpha emitters (241Am, 237Np, 239Pu, 232Th) in biological media (urine and feces)

    International Nuclear Information System (INIS)

    Bataller, Georges; Vasson, Olivier de; Bazin, Roger; Bonnard, Danielle; Morello, Marcel.

    1979-01-01

    A technique is described in this paper which permits the determination of the gross alpha activity emitted by a mixture of specially radiotoxic elements in urine and feces. After reduction and adjustment of the solution at pH 5,0, the radionuclides are adsorbed on glass marbles. The elution is made in acid medium (HCl 6N). Under these conditions the chemical yields are very satisfying: 96+-6% for urine and 68+-9% for feces. In case of significant results at the end of the manipulation, the radioactive source quality is sufficient to allow the identification of the contaminating radionuclide(s) by alpha spectrometry [fr

  2. Internal emitter limits for iodine, radium and radon daughters

    Energy Technology Data Exchange (ETDEWEB)

    Schlenker, R.A.

    1984-08-15

    This paper identifies some of the issues which arise in the consideration of the derivation of new limits on exposure to internal emitters. Basic and secondary radiation protection limits are discussed. Terms are defined and applied to the limitation of risk from stochastic effects. Non-stochastic data for specific internal emitters (/sup 131/I and the radium isotopes) are presented. Emphasis is placed on the quantitative aspects of the limit setting problem. 65 references, 2 figures, 12 tables.

  3. Transverse emittance measurement at REGAE via a solenoid scan

    Energy Technology Data Exchange (ETDEWEB)

    Hachmann, Max; Mayet, Frank; Gruener, Florian [Institut fuer Experimentalphysik, Universitaet Hamburg (Germany); Floettmann, Klaus [DESY, Hamburg (Germany)

    2013-07-01

    The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. The current method to measure the transverse beam emittance at REGAE and results are presented.

  4. Quantum emitters coupled to surface plasmons of an nanowire

    DEFF Research Database (Denmark)

    Dzsotjan, David; Sørensen, Anders Søndberg; Fleischhauer, Michael

    2010-01-01

    We investigate a system consisting of a single, as well as two emitters strongly coupled to surface plasmon modes of a nanowire using a Green's function approach. Explicit expressions are derived for the spontaneous decay rate into the plasmon modes and for the atom-plasmon coupling as well......-qubit quantum gate. We also discuss a possible realization of interesting many-body Hamiltonians, such as the spin-boson model, using strong emitter-plasmon coupling. Udgivelsesdato: 27 August...

  5. Internal emitter limits for iodine, radium and radon daughters

    International Nuclear Information System (INIS)

    Schlenker, R.A.

    1984-01-01

    This paper identifies some of the issues which arise in the consideration of the derivation of new limits on exposure to internal emitters. Basic and secondary radiation protection limits are discussed. Terms are defined and applied to the limitation of risk from stochastic effects. Non-stochastic data for specific internal emitters ( 131 I and the radium isotopes) are presented. Emphasis is placed on the quantitative aspects of the limit setting problem. 65 references, 2 figures, 12 tables

  6. Low Emittance Guns for the ILC Polarized Electron Beam

    International Nuclear Information System (INIS)

    Clendenin, J. E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R. E.; Maruyama, T.; Miller, R. H.; Wang, J. W.; Zhou, F.

    2007-01-01

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of ≥200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while ≥500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

  7. Low Emittance Guns for the ILC Polarized Electron Beam

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.H.; Wang, J.W.; Zhou, F.; SLAC

    2006-01-01

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of (ge)200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while (ge)500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns

  8. Emittance growth caused by bends in the Los Alamos free-electron laser energy recovery experiment

    International Nuclear Information System (INIS)

    Carlsten, B.E.

    1987-01-01

    Experimentally transporting the beam from the wiggler to the decelerators in the energy recovery experiment (ERX) at the Los Alamos National Laboratory free-electron laser was more difficult than expected because of the large initial emittance in the beam. This emittance was apparently caused in an early 60 0 achromatic bend. To get this beam through subsequent bends without wall interception, the quadrupole focusing had to be changed from the design amount; as a result, the emittance grew further. This paper discusses various mechanisms for this emittance growth in the 60 0 bend, including effects caused by path changes in the bend resulting from wake-field-induced energy changes of particles in the beam and examines emittance filters, ranging from a simple aperture near a beam crossover to more complicated telescope schemes designed to regain the original emittance before the 60 0 bend

  9. Low-Cost alpha Alane for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Tibor [Ardica Technologies, San Francisco, CA (United States); Petrie, Mark [SRI International, Menlo Park, CA (United States); Crouch-Baker, Steven [SRI International, Menlo Park, CA (United States); Fong, Henry [SRI International, Menlo Park, CA (United States)

    2017-10-10

    This project was directed towards the further development of the Savannah River National Laboratory (SRNL) lab-scale electrochemical synthesis of the hydrogen storage material alpha-alane and Ardica Technologies-SRI International (SRI) chemical downstream processes that are necessary to meet DoE cost metrics and transition alpha-alane synthesis to an industrial scale. Ardica has demonstrated the use of alpha-alane in a fuel-cell system for the U.S. Army WFC20 20W soldier power system that has successfully passed initial field trials with individual soldiers. While alpha-alane has been clearly identified as a desirable hydrogen storage material, cost-effective means for its production and regeneration on a scale of use applicable to the industry have yet to be established. We focused on three, principal development areas: 1. The construction of a comprehensive engineering techno-economic model to establish the production costs of alpha-alane by both electrochemical and chemical routes at scale. 2. The identification of critical, cost-saving design elements of the electrochemical cell and the quantification of the product yields of the primary electrochemical process. A moving particle-bed reactor design was constructed and operated. 3. The experimental quantification of the product yields of candidate downstream chemical processes necessary to produce alpha-alane to complete the most cost-effective overall manufacturing process. Our techno-economic model shows that under key assumptions most 2015 and 2020 DOE hydrogen storage system cost targets for low and medium power can be achieved using the electrochemical alane synthesis process. To meet the most aggressive 2020 storage system cost target, $1/g, our model indicates that 420 metric tons per year (MT/y) production of alpha-alane is required. Laboratory-scale experimental work demonstrated that the yields of two of the three critical component steps within the overall “electrochemical process” were

  10. Space-charge driven emittance growth in a 3D mismatched anisotropic beam

    International Nuclear Information System (INIS)

    Qiang, J.; Ryne, R.D.; Hofmann, I.

    2002-01-01

    In this paper we present a 3D simulation study of the emittance growth in a mismatched anisotropic beam. The equipartitioning driven by a 4th order space-charge resonance can be significantly modified by the presence of mismatch oscillation and halo formation. This causes emittance growth in both the longitudinal and transverse directions which could drive the beam even further away from equipartition. The averaged emittance growth per degree freedom follows the upper bound of the 2D free energy limit plus the contributions from equipartitioning

  11. Selección tecnico-economica de emisores Technical and economical selection of emitters

    Directory of Open Access Journals (Sweden)

    Eduardo A. Holzapfel

    2007-12-01

    Full Text Available El presente trabajo tuvo como objetivo estudiar los factores que intervienen en la selección técnico económico de goteros. En el estudio fueron utilizados emisores autocompensados y no autocompensados, considerando a los aspectos técnicos como porcentaje de suelo humedecido, número de emisores por planta y coeficiente de uniformidad y precio y la presión de operación del emisor como aspectos económicos. Los resultados muestran que la presión de operación de los emisores es el factor más importante a considerar en la selección, ya que para valores más bajos de presión de operación se obtuvieron menores valores de costo total anualizado, independiente del tipo de gotero. En general, los goteros no autocompesados presentaron valores de costo anualizado menores, para un rango de presión similar. Finalmente el análisis tecnico-económico en la selección de emisores es un procedimiento importante.The objective of this research was to study the parameters that affect the technical-economical selection of emitters. In the study compensated and non-compensated emitters were used. The technical aspects considered were: percentage of wetted soil, number of emitters per plant and the uniformity coefficient as well as price and operation pressure for economic aspects. The results shows that the operation pressure of emitters is the most important factor to be considered in the selection , with smaller values of pressure giving lower total annual cost, independently of the type of emitter. In general, the non-compensated emitter shows lower annual cost values than for compensated emitters, for a similar range of pressures. Finally the technical-economical analysis in the emitter selection is an important procedure.

  12. Previous study for the setting up and optimization of detection of ZnS(Ag) scintillation applied to the measure of alpha radioactivity index

    International Nuclear Information System (INIS)

    Pujol, L.; Suarez-Navarro, J.A.; Montero, M.

    1998-01-01

    The determination of radiological water quality is useful for a wide range of environmental studies. In these cases, the gross alpha activity is one of the parameters to determine. This parameter permits to decide if further radiological analyses are necessary in order to identify and quantify the presence of alpha emitters in water. The usual method for monitoring the gross alpha activity includes sample evaporation to dryness on a disk and counting using ZnS(Ag) scintillation detector. Detector electronics is provided with two components which are adjustable by the user the high-voltage applied to the photomultiplier tubes and the low level discriminator that is used to eliminate the electronic noise. The high-voltage and low level discriminator optimization are convenient in order to reach the best counting conditions. This paper is a preliminary study of the procedure followed for the setting up and optimization of the detector electronics in the laboratories of CEDEX for the measurement of gross alpha activity. (Author)

  13. Compact Rare Earth Emitter Hollow Cathode

    Science.gov (United States)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  14. INFERENCES ON THE DISTRIBUTION OF Ly{alpha} EMISSION OF z {approx} 7 AND z {approx} 8 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Treu, Tommaso; Auger, Matthew W. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Trenti, Michele [University of Colorado, Center for Astrophysics and Space Astronomy, 389-UCB, Boulder, CO 80309 (United States); Stiavelli, Massimo; Bradley, Larry D., E-mail: tt@physics.ucsb.edu [Space Telescope Science Institute, 3700 San Martin Dr, Baltimore MD 21218 (United States)

    2012-03-01

    Spectroscopic confirmation of galaxies at z {approx} 7 and above has been extremely difficult, owing to a drop in intensity of Ly{alpha} emission in comparison with samples at z {approx} 6. This crucial finding could potentially signal the ending of cosmic reionization. However, it is based on small data sets, often incomplete and heterogeneous in nature. We introduce a flexible Bayesian framework, useful to interpret such evidence. Within this framework, we implement two simple phenomenological models: a smooth one where the distribution of Ly{alpha} is attenuated by a factor {epsilon}{sub s} with respect to z {approx} 6 and a patchy one where a fraction {epsilon}{sub p} is absorbed/non-emitted while the rest is unabsorbed. From a compilation of 39 observed z {approx} 7 galaxies, we find {epsilon}{sub s} = 0.69 {+-} 0.12 and {epsilon}{sub p} = 0.66 {+-} 0.16. The models can be used to compute fractions of emitters above any equivalent width W. For W > 25 A, we find X{sup 25}{sub z=7} = 0.37 {+-} 0.11 (0.14 {+-} 0.06) for galaxies fainter (brighter) than M{sub UV} = -20.25 for the patchy model, consistent with previous work, but with smaller uncertainties by virtue of our full use of the data. At z {approx} 8 we combine new deep (5{sigma} flux limit 10{sup -17} erg s{sup -1} cm{sup -2}) Keck/NIRSPEC observations of a bright Y-dropout identified by our Brightest of Reionization Galaxies Survey, with those of three objects from the literature and find that the inference is inconclusive. We compute predictions for future near-infrared spectroscopic surveys and show that it is challenging but feasible to constrain the distribution of Ly{alpha} emitters at z {approx} 8 and distinguish between models.

  15. An analytical model to calculate absorbed fractions for internal dosimetry with alpha, beta and gamma emitters

    OpenAIRE

    Amato, Ernesto; Italiano, Antonio; Baldari, Sergio

    2014-01-01

    We developed a general model for the calculation of absorbed fractions in ellipsoidal volumes of soft tissue uniformly filled with alpha, beta and gamma emitting radionuclides. The approach exploited Monte Carlo simulations with the Geant4 code to determine absorbed fractions in ellipsoids characterized by a wide range of dimensions and ellipticities, for monoenergetic emissions of each radiation type. The so-obtained absorbed fractions were put in an analytical relationship with the 'general...

  16. Defect production in nonlinear quench across a quantum critical point.

    Science.gov (United States)

    Sen, Diptiman; Sengupta, K; Mondal, Shreyoshi

    2008-07-04

    We show that the defect density n, for a slow nonlinear power-law quench with a rate tau(-1) and an exponent alpha>0, which takes the system through a critical point characterized by correlation length and dynamical critical exponents nu and z, scales as n approximately tau(-alphanud/(alphaznu+1)) [n approximately (alphag((alpha-1)/alpha)/tau)(nud/(znu+1))] if the quench takes the system across the critical point at time t=0 [t=t(0) not = 0], where g is a nonuniversal constant and d is the system dimension. These scaling laws constitute the first theoretical results for defect production in nonlinear quenches across quantum critical points and reproduce their well-known counterpart for a linear quench (alpha=1) as a special case. We supplement our results with numerical studies of well-known models and suggest experiments to test our theory.

  17. Source brightness and useful beam current of carbon nanotubes and other very small emitters

    International Nuclear Information System (INIS)

    Kruit, P.; Bezuijen, M.; Barth, J.E.

    2006-01-01

    The potential application of carbon nanotubes as electron sources in electron microscopes is analyzed. The resolution and probe current that can be obtained from a carbon nanotube emitter in a low-voltage scanning electron microscope are calculated and compared to the state of the art using Schottky electron sources. Many analytical equations for probe-size versus probe-current relations in different parameter regimes are obtained. It is shown that for most carbon nanotube emitters, the gun lens aberrations are larger than the emitters' virtual source size and thus restrict the microscope's performance. The result is that the advantages of the higher brightness of nanotube emitters are limited unless the angular emission current is increased over present day values or the gun lens aberrations are decreased. For some nanotubes with a closed cap, it is known that the emitted electron beam is coherent over the full emission cone. We argue that for such emitters the parameter ''brightness'' becomes meaningless. The influence of phase variations in the electron wave front emitted from such a nanotube emitter on the focusing of the electron beam is analyzed

  18. A Program to Generate a Particle Distribution from Emittance Measurements

    CERN Document Server

    Bouma, DS; Lallement, JB

    2010-01-01

    We have written a program to generate a particle distribution based on emittance measurements in x-x’ and y-y’. The accuracy of this program has been tested using real and constructed emittance measurements. Based on these tests, the distribution generated by the program can be used to accurately simulate the beam in multi-particle tracking codes, as an alternative to a Gaussian or uniform distribution.

  19. Experimental Study of Coherent Synchrotron Radiation in the Emittance Exchange Line at the A0-Photoinjector

    Science.gov (United States)

    Thangaraj, Jayakar C. T.; Thurman-Keup, R.; Johnson, A.; Lumpkin, A. H.; Edwards, H.; Ruan, J.; Santucci, J.; Sun, Y. E.; Church, M.; Piot, P.

    2010-11-01

    Next generation accelerators will require a high current, low emittance beam with a low energy spread. Such accelerators will employ advanced beam conditioning systems such as emittance exchangers to manipulate high brightness beams. One of the goals of the Fermilab A0 photoinjector is to investigate the transverse to longitudinal emittance exchange principle. Coherent synchrotron radiation could limit high current operation of the emittance exchanger. In this paper, we report on the preliminary experimental and simulation study of the coherent synchroton radiation (CSR) in the emittance exchange line at the A0 photoinjector.

  20. Plexciton quenching by resonant electron transfer from quantum emitter to metallic nanoantenna.

    Science.gov (United States)

    Marinica, D C; Lourenço-Martins, H; Aizpurua, J; Borisov, A G

    2013-01-01

    Coupling molecular excitons and localized surface plasmons in hybrid nanostructures leads to appealing, tunable optical properties. In this respect, the knowledge about the excitation dynamics of a quantum emitter close to a plasmonic nanoantenna is of importance from fundamental and practical points of view. We address here the effect of the excited electron tunneling from the emitter into a metallic nanoparticle(s) in the optical response. When close to a plasmonic nanoparticle, the excited state localized on a quantum emitter becomes short-lived because of the electronic coupling with metal conduction band states. We show that as a consequence, the characteristic features associated with the quantum emitter disappear from the optical absorption spectrum. Thus, for the hybrid nanostructure studied here and comprising quantum emitter in the narrow gap of a plasmonic dimer nanoantenna, the quantum tunneling might quench the plexcitonic states. Under certain conditions the optical response of the system approaches that of the individual plasmonic dimer. Excitation decay via resonant electron transfer can play an important role in many situations of interest such as in surface-enhanced spectroscopies, photovoltaics, catalysis, or quantum information, among others.

  1. Polarization measurements made on LFRA and OASIS emitter arrays

    Science.gov (United States)

    Geske, Jon; Sparkman, Kevin; Oleson, Jim; Laveigne, Joe; Sieglinger, Breck; Marlow, Steve; Lowry, Heard; Burns, James

    2008-04-01

    Polarization is increasingly being considered as a method of discrimination in passive sensing applications. In this paper the degree of polarization of the thermal emission from the emitter arrays of two new Santa Barbara Infrared (SBIR) micro-bolometer resistor array scene projectors was characterized at ambient temperature and at 77 K. The emitter arrays characterized were from the Large Format Resistive Array (LFRA) and the Optimized Arrays for Space-Background Infrared Simulation (OASIS) scene projectors. This paper reports the results of this testing.

  2. Emittance studies of the 2.45 GHz permanent magnet ECR ion source

    Science.gov (United States)

    Zelenak, A.; Bogomolov, S. L.; Yazvitsky, N. Yu.

    2004-05-01

    During the past several years different types of permanent magnet 2.45 GHz (electron cyclotron resonance) ion sources were developed for production of singly charged ions. Ion sources of this type are used in the first stage of DRIBs project, and are planned to be used in the MASHA mass separator. The emittance of the beam provided by the source is one of the important parameters for these applications. An emittance scanner composed from a set of parallel slits and rotary wire beam profile monitor was used for the studying of the beam emittance characteristics. The emittance of helium and argon ion beams was measured with different shapes of the plasma electrode for several ion source parameters: microwave power, source potential, plasma aperture-puller aperture gap distance, gas pressure. The results of measurements are compared with previous simulations of ion optics.

  3. Emittance studies of the 2.45 GHz permanent magnet ECR ion source

    International Nuclear Information System (INIS)

    Zelenak, A.; Bogomolov, S.L.; Yazvitsky, N.Yu.

    2004-01-01

    During the past several years different types of permanent magnet 2.45 GHz (electron cyclotron resonance) ion sources were developed for production of singly charged ions. Ion sources of this type are used in the first stage of DRIBs project, and are planned to be used in the MASHA mass separator. The emittance of the beam provided by the source is one of the important parameters for these applications. An emittance scanner composed from a set of parallel slits and rotary wire beam profile monitor was used for the studying of the beam emittance characteristics. The emittance of helium and argon ion beams was measured with different shapes of the plasma electrode for several ion source parameters: microwave power, source potential, plasma aperture-puller aperture gap distance, gas pressure. The results of measurements are compared with previous simulations of ion optics

  4. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  5. Study of transfer reactions ({alpha},t), ({alpha},{sup 3}He) in the f-p shell: mechanism and spectroscopic use; Etude des reactions de transfert ({alpha},t), ({alpha},{sup 3}He) dans la couche f-p mecanisme et utilisation spectroscopique

    Energy Technology Data Exchange (ETDEWEB)

    Roussel, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-05-01

    We describe an experimental study of ({alpha},t), ({alpha},{sup 3}He) reactions at 44 MeV using a solid-state identifier, on the target-nuclei {sup 54}Fe and {sup 58,60,62,64}Ni. A critical study of optical model and of disturbed wave analysis has been performed. We show the complementarity of different transfer-reactions, the ambiguity of spectroscopic factors, the importance of the problem of the reaction mechanism. (author) [French] On decrit une etude experimentale des reactions ({alpha},t), ({alpha},{sup 3}He) a 44 MeV utilisant un systeme identificateur de particules sur les noyaux-cibles {sup 54}Fe et {sup 58,60,62,64}Ni. Une etude critique de modele optique et d'analyse en ondes deformees (D.W.B.A.) a ete entreprise. On montre la complementarite des differentes reactions de transfert, l'ambiguite des facteurs spectroscopiques, l'importance du probleme du mecanisme. (auteur)

  6. Emittance measuring system on the UNILAC

    International Nuclear Information System (INIS)

    Ehrich, A.; Glatz, J.; Strahl, P.

    A description is given of one of the beam emittance measuring systems designed for the UNILAC at GSI. The measuring system mechanics and the detector system are detailed, and the associated electronics are discussed. Computer programming and data processing and evaluation are described

  7. Simple emittance measurement of negative hydrogen ion beam using pepper-pot method

    International Nuclear Information System (INIS)

    Hamabe, M.; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Asano, E.; Kawamoto, T.; Kuroda, T.; Guharay, S.K.

    1997-01-01

    A simple apparatus for emittance measurement using pepper-pot method is developed. The pepper-pot patterns are directly exposed and recorded on a Kapton foil. Using this apparatus, emittance was measured in the case of the negative hydrogen (H - ) beam from the large negative ion source, which is the 1/3 scaled test device for the negative-ion-based neutral beam injection (N-NBI) on the Large Helical Device (LHD). As the consequence of the first trial, the 95% normalized emittance value is measured as 0.59 mm mrad. (author)

  8. Simple emittance measurement of negative hydrogen ion beam using pepper-pot method

    Energy Technology Data Exchange (ETDEWEB)

    Hamabe, M.; Tsumori, K.; Takeiri, Y.; Kaneko, O.; Asano, E.; Kawamoto, T.; Kuroda, T. [National Inst. for Fusion Science, Nagoya (Japan); Guharay, S.K.

    1997-02-01

    A simple apparatus for emittance measurement using pepper-pot method is developed. The pepper-pot patterns are directly exposed and recorded on a Kapton foil. Using this apparatus, emittance was measured in the case of the negative hydrogen (H{sup -}) beam from the large negative ion source, which is the 1/3 scaled test device for the negative-ion-based neutral beam injection (N-NBI) on the Large Helical Device (LHD). As the consequence of the first trial, the 95% normalized emittance value is measured as 0.59 mm mrad. (author)

  9. Effects of emittance and space-charge in femtosecond bunch compression

    International Nuclear Information System (INIS)

    Kan, K.; Yang, J.; Kondoh, T.; Norizawa, K.; Yoshida, Y.

    2008-01-01

    Ultrashort electron bunches of the order of <100fs are essential for the study of ultrafast reactions and phenomena by means of time-resolved pump-probe experiments. In order to generate such an electron bunch, the effects of emittance, space-charge (SC) and coherent synchrotron radiation (CSR) on the bunch length in a femtosecond magnetic bunch compressor were studied theoretically. It was observed that the bunch length is dominated by the emittance, SC and CSR effects when the electron bunch is compressed into a femtosecond electron bunch. The increases in bunch length due to the transverse emittance, SC and CSR effects in the bunch compressor were 1.7 fs/mm mrad, 107 fs/nC and 72 fs/nC, respectively. Finally, the simulated bunch length was compared with the experimental results.

  10. Emittance growth in coast in the SPS

    CERN Document Server

    Alekou, A; Bartosik, H; Calaga, R

    2017-01-01

    The CERN SPS will be used as a test-bed for the LHCprototype crab-cavities, which will be installed and testedin the SPS in 2018. As the time available for experimen-tal beam dynamics studies with the crab cavities installedin the machine will be limited, a very good preparation isrequired in advance. One of the main concerns is the in-duced emittance growth, driven by phase jitter in the crabcavities. In this respect, several machine development (MD)studies were performed during the past years to quantifyand characterize the emittance evolution of proton beamsin coast in the SPS. In these proceedings, the experimentalobservations from past years are summarized and the MDstudies from 2016 are presented. Finally, a proposal for anexperimental program for 2017 is discussed.

  11. Decoupling Intensity Radiated by the Emitter in Distance Estimation from Camera to IR Emitter

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Luna Vázquez

    2013-05-01

    Full Text Available Various models using radiometric approach have been proposed to solve the problem of estimating the distance between a camera and an infrared emitter diode (IRED. They depend directly on the radiant intensity of the emitter, set by the IRED bias current. As is known, this current presents a drift with temperature, which will be transferred to the distance estimation method. This paper proposes an alternative approach to remove temperature drift in the distance estimation method by eliminating the dependence on radiant intensity. The main aim was to use the relative accumulated energy together with other defined models, such as the zeroth-frequency component of the FFT of the IRED image and the standard deviation of pixel gray level intensities in the region of interest containing the IRED image. By using the abovementioned models, an expression free of IRED radiant intensity was obtained. Furthermore, the final model permitted simultaneous estimation of the distance between the IRED and the camera and the IRED orientation angle. The alternative presented in this paper gave a 3% maximum relative error over a range of distances up to 3 m.

  12. Quantitative single-particle digital autoradiography with α-particle emitters for targeted radionuclide therapy using the iQID camera

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Brian W., E-mail: brian.miller@pnnl.gov [Pacific Northwest National Laboratory, Richland, Washington 99354 and College of Optical Sciences, The University of Arizona, Tucson, Arizona 85719 (United States); Frost, Sofia H. L.; Frayo, Shani L.; Kenoyer, Aimee L.; Santos, Erlinda; Jones, Jon C.; Orozco, Johnnie J. [Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 (United States); Green, Damian J.; Press, Oliver W.; Pagel, John M.; Sandmaier, Brenda M. [Fred Hutchinson Cancer Research Center, Seattle, Washington 98109 and Department of Medicine, University of Washington, Seattle, Washington 98195 (United States); Hamlin, Donald K.; Wilbur, D. Scott [Department of Radiation Oncology, University of Washington, Seattle, Washington 98195 (United States); Fisher, Darrell R. [Dade Moeller Health Group, Richland, Washington 99354 (United States)

    2015-07-15

    Purpose: Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50–80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antibodies labeled with α emitters may thus inactivate targeted cells with minimal radiation damage to surrounding tissues. Tools are needed to visualize and quantify the radioactivity distribution and absorbed doses to targeted and nontargeted cells for accurate dosimetry of all treatment regimens utilizing α particles, including RIT and others (e.g., Ra-223), especially for organs and tumors with heterogeneous radionuclide distributions. The aim of this study was to evaluate and characterize a novel single-particle digital autoradiography imager, the ionizing-radiation quantum imaging detector (iQID) camera, for use in α-RIT experiments. Methods: The iQID camera is a scintillator-based radiation detection system that images and identifies charged-particle and gamma-ray/x-ray emissions spatially and temporally on an event-by-event basis. It employs CCD-CMOS cameras and high-performance computing hardware for real-time imaging and activity quantification of tissue sections, approaching cellular resolutions. In this work, the authors evaluated its characteristics for α-particle imaging, including measurements of intrinsic detector spatial resolutions and background count rates at various detector configurations and quantification of activity distributions. The technique was assessed for quantitative imaging of astatine-211 ({sup 211}At) activity distributions in cryosections of murine and canine tissue samples. Results: The highest spatial resolution was measured at ∼20 μm full width at half maximum and the α-particle background was measured at a rate as low as (2.6 ± 0.5) × 10{sup −4} cpm/cm{sup 2} (40 mm diameter detector area

  13. Transverse and longitudinal emittance measurements in the ELSA linac

    International Nuclear Information System (INIS)

    Loulergue, A.; Dowell, D.H.; Joly, S.; De Brion, J.P.; Haouat, G.; Schumann, F.

    1997-01-01

    The ELSA RF linac photoinjector has been designed to deliver high-brightness electron beams. The present paper deals with the transverse and longitudinal emittance measurements, at different locations along the ELSA beam line, and the analysis of their variations as a function of the photoinjector parameters : magnetic field generated by the anode focusing lens, bunch charge and pulse duration. While transverse emittance has been already studied in other similar installations, there has been little study of the electron beam longitudinal dynamics. Experimental results are presented and compared to simulation-code expectations. For 2.0 nC, 85 A electron bunches, a normalized rms emittance of 2 π mm mrad and a brightness of 4.5 x 10 13 A/(π m rad) 2 at the linac exit have been measured as well as less than 10 keV rms energy spread (or less than 0.1% at 16.5 MeV). (orig.)

  14. The influence of the calibration standard and the chemical composition of the water samples residue in the counting efficiency of proportional detectors for gross alpha and beta counting. Application on the radiologic control of the IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Santos, Cecilia Martins

    2003-01-01

    In this work the efficiency calibration curves of thin-window and low background gas-flow proportional counters were determined for calibration standards with different energies and different absorber thicknesses. For the gross alpha counting we have used 241 Am and natural uranium standards and for the gross beta counting we have used 90 Sr/ 90 Y and 137 Cs standards in residue thicknesses ranging from 0 to approximately 18 mg/cm 2 . These sample thicknesses were increased with a previously determined salted solution prepared simulating the chemical composition of the underground water of IPEN The counting efficiency for alpha emitters ranged from 0,273 +- 0,038 for a weightless residue to only 0,015 +- 0,002 in a planchet containing 15 mg/cm 2 of residue for 241 Am standard. For natural uranium standard the efficiency ranged from 0,322 +- 0,030 for a weightless residue to 0,023 +- 0,003 in a planchet containing 14,5 mg/cm 2 of residue. The counting efficiency for beta emitters ranged from 0,430 +- 0,036 for a weightless residue to 0,247 +- 0,020 in a planchet containing 17 mg/cm 2 of residue for 137 Cs standard. For 90 Sr/ 90 Y standard the efficiency ranged from 0,489 +- 0,041 for a weightless residue to 0,323 +- 0,026 in a planchet containing 18 mg/cm 2 of residue. Results make evident the counting efficiency variation with the alpha or beta emitters energies and the thickness of the water samples residue. So, the calibration standard, the thickness and the chemical composition of the residue must always be considered in the gross alpha and beta radioactivity determination in water samples. (author)

  15. Importance of salt in the production matrix of the efficiency curve for the determination of the total alpha activity in water samples; Importancia de la matriz salina en la fabricacion de la curva de eficiencia para la determinacion del indice de actividad alfa total en muestras de agua

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Corbacho, J. A.

    2011-07-01

    The determination of total alpha activity by the evaporation method allows obtaining, from a quick and inexpensive technique, the order of magnitude of the total activity of all alpha emitters present in a sample of water. This study shows that the detection efficiency curve varies significantly depending on the sodium salt is used to manufacture calibration and/or reference radionuclide used. (Author)

  16. Negative ion emission at field electron emission from amorphous (alpha-C:H) carbon

    CERN Document Server

    Bernatskij, D P; Ivanov-Omskij, V I; Pavlov, V G; Zvonareva, T K

    2001-01-01

    The study on the electrons field emission from the plane cathode surface on the basis of the amorphous carbon film (alpha-C:H) is carried out. The methodology, making it possible to accomplish simultaneously the registration of the emission currents and visually observe the distribution of the emission centers on the plane emitter surface is developed. The analysis of the oscillograms indicated that apart from the proper electron constituent the negative ions of hydrogen (H sup - and H sub 2 sup -), carbon (C sup -) and hydrocarbon (CH sub n sup -) are observed. The ions emission is connected with the processes of formation and degradation of the local emission centers

  17. Simple-to-prepare multipoint field emitter

    Science.gov (United States)

    Sominskii, G. G.; Taradaev, E. P.; Tumareva, T. A.; Mishin, M. V.; Kornishin, S. Yu.

    2015-07-01

    We investigate multitip field emitters prepared by electroerosion treatment of the surface of molybdenum samples. Their characteristics are determined for operation with a protecting activated fullerene coating. Our experiments indicate that such cathodes are promising for high-voltage electron devices operating in technical vacuum.

  18. Radial-velocity variations in Alpha Ori, Alpha Sco, and Alpha Her

    International Nuclear Information System (INIS)

    Smith, M.A.; Patten, B.M.; Goldberg, L.

    1989-01-01

    Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A are used to study radial-velocity periodicities in M supergiants. The data refer to several metallic lines in the H-alpha region and to H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested that many semiregular red supergiant varibles such as Alpha Ori may be heading toward chaos. All three stars show short-term stochastic flucutations with an amplitude of 1-2 km/s. It is found that the long-term variability of H-alpha velocities may be a consequence of intermittent failed ejections. 58 refs

  19. Characterization of microstructured fibre emitters: in pursuit of improved nano electrospray ionization performance.

    Science.gov (United States)

    Wu, Xinyun; Oleschuk, Richard D; Cann, Natalie M

    2012-09-21

    Full-dimensional computational fluid dynamics (CFD) simulations are presented for nano electrospray ionization (ESI) with various emitter designs. Our CFD electrohydrodynamic simulations are based on the Taylor-Melcher leaky-dielectric model, and the volume of fluid technique for tracking the fast-changing liquid-gas interface. The numerical method is first validated for a conventional 20 μm inner diameter capillary emitter. The impact of ESI voltage, flow rate, emitter tapering, surface hydrophobicity, and fluid conductivity on the nano-ESI behavior are thoroughly investigated and compared with experiments. Multi-electrospray is further simulated with 2-hole and 3-hole emitters with the latter having a linear or triangular hole arrangement. The simulations predict multi-electrospray behavior in good agreement with laboratory observations.

  20. The membrane-cytoplasm interface of integrin alpha subunits is critical for receptor latency.

    OpenAIRE

    Briesewitz, R; Kern, A; Smilenov, L B; David, F S; Marcantonio, E E

    1996-01-01

    Localization of integrin receptors to focal contact sites occurs upon ligand binding. This activity is latent, since unoccupied integrin receptors do not localize to focal contacts. Deletion analysis has revealed that the alpha cytoplasmic domains is required for the maintenance of integrin receptor latency. Our current hypothesis for the mechanism of integrin post-ligand binding events is that there is a change in relationship of alpha and beta cytoplasmic domains, which overcomes receptor l...

  1. Mirrorless lasing from light emitters in percolating clusters

    Science.gov (United States)

    Burlak, Gennadiy; Rubo, Y. G.

    2015-07-01

    We describe the lasing effect in the three-dimensional percolation system, where the percolating cluster is filled by active media composed by light emitters excited noncoherently. We show that, due to the presence of a topologically nontrivial photonic structure, the stimulated emission is modified with respect to both conventional and random lasers. The time dynamics and spectra of the lasing output are studied numerically with finite-difference time-domain approach. The Fermat principle and Monte Carlo approach are applied to characterize the optimal optical path and interconnection between the radiating emitters. The spatial structure of the laser mode is found by a long-time FDTD simulation.

  2. Functional activities of receptors for tumor necrosis factor-alpha on human vascular endothelial cells.

    NARCIS (Netherlands)

    Paleolog, E.M.; Delasalle, S.A.; Buurman, W.A.; Feldmann, M.

    1994-01-01

    Tumor necrosis factor-alpha (TNF-alpha) plays a critical role in the control of endothelial cell function and hence in regulating traffic of circulating cells into tissues in vivo. Stimulation of endothelial cells in vitro by TNF-alpha increases the surface expression of leukocyte adhesion

  3. Impact of Optics on CSR-Related Emittance Growth in Bunch Compressor Chicanes

    CERN Document Server

    Limberg, Torsten

    2005-01-01

    The dependence of emittance growth due to Coherent Synchrotron Radiation (CSR) in bunch compressor chicanes on optics has been noticed and empirically studied in the past. We revisit the subject, suggesting a model to explain slice emittance growth dependence on chicane optics. A simplified model to calculate projected emittance growth when it is mainly caused by transverse slice centroid offsets is presented. It is then used to find optimal compensation of centroid kicks in the single chicanes of a two-stage compression system by adjusting the phase advance of the transport in between and the ration of the compression factors.

  4. Stability of zinc stearate under alpha irradiation in the manufacturing process of SFR nuclear fuels

    Science.gov (United States)

    Gracia, J.; Vermeulen, J.; Baux, D.; Sauvage, T.; Venault, L.; Audubert, F.; Colin, X.

    2018-03-01

    The manufacture of new fuels for sodium-cooled fast reactors (SFRs) will involve powders derived from recycling existing fuels in order to keep on producing electricity while saving natural resources and reducing the amount of waste produced by spent MOX fuels. Using recycled plutonium in this way will significantly increase the amount of 238Pu, a high energy alpha emitter, in the powders. The process of shaping powders by pressing requires the use of a solid lubricant, zinc stearate, to produce pellets with no defects compliant with the standards. The purpose of this study is to determine the impact of alpha radiolysis on this additive and its lubrication properties. Experiments were conducted on samples in contact with PuO2, as well as under external helium ion beam irradiation, in order to define the kinetics of radiolytic gas generation. The yield results relating to the formation of these gases (G0) show that the alpha radiation of plutonium can be simulated using external helium ion beam irradiation. The isotopic composition of plutonium has little impact on the yield. However, an increased yield was globally observed with increasing the mean linear energy transfer (LET). A radiolytic degradation process is proposed.

  5. Reducing longitudinal emittance growth in RFQ accelerators

    International Nuclear Information System (INIS)

    Koscielniak, S.

    1994-08-01

    Bunching and capture of a monochromatic beam into an rf bucket inevitably lead to substantial emittance growth through the mechanisms of filamentation and non-adiabatic variation of parameters. We describe a three step strategy for minimizing this growth, based on a clear understanding of the non-linear beam dynamics, and apply to acceleration of heavy ions with Z/A = 1/60 (and initial kinetic energy 60 keV/u) in a radio frequency quadrupole (RFQ) operating at 25 MHz. We also describe a scheme, to further reduce the emittance, based upon the use of an external RFQ-type prebuncher before the main accelerator. The external unit permits the bunching voltage to be reduced, to inject into a moving bucket, and to reduce the structure length. (author). 7 refs., 6 figs

  6. Hypoxia inducible factor 1-alpha (HIF-1 alpha is induced during reperfusion after renal ischemia and is critical for proximal tubule cell survival.

    Directory of Open Access Journals (Sweden)

    Elisa Conde

    Full Text Available Acute tubular necrosis (ATN caused by ischemia/reperfusion (I/R during renal transplantation delays allograft function. Identification of factors that mediate protection and/or epithelium recovery could help to improve graft outcome. We studied the expression, regulation and role of hypoxia inducible factor 1-alpha (HIF-1 α, using in vitro and in vivo experimental models of I/R as well as human post-transplant renal biopsies. We found that HIF-1 α is stabilized in proximal tubule cells during ischemia and unexpectedly in late reperfusion, when oxygen tension is normal. Both inductions lead to gene expression in vitro and in vivo. In vitro interference of HIF-1 α promoted cell death and in vivo interference exacerbated tissue damage and renal dysfunction. In pos-transplant human biopsies, HIF-1 α was expressed only in proximal tubules which exhibited normal renal structure with a significant negative correlation with ATN grade. In summary, using experimental models and human biopsies, we identified a novel HIF-1 α induction during reperfusion with a potential critical role in renal transplant.

  7. Human fat cell alpha-2 adrenoceptors. I. Functional exploration and pharmacological definition with selected alpha-2 agonists and antagonists

    International Nuclear Information System (INIS)

    Galitzky, J.; Mauriege, P.; Berlan, M.; Lafontan, M.

    1989-01-01

    This study was undertaken to investigate more fully the pharmacological characteristics of the human fat cell alpha-2 adrenoceptor. Biological assays were performed on intact isolated fat cells while radioligand binding studies were carried out with [ 3 H]yohimbine in membranes. These pharmacological studies brought: (1) a critical definition of the limits of the experimental conditions required for the exploration of alpha-2 adrenergic responsiveness on human fat cells and membranes; (2) an improvement in the pharmacological definition of the human fat cell postsynaptic alpha-2 adrenoceptor. Among alpha-2 agonists, UK-14,304 was the most potent and the relative order of potency was: UK-14,304 greater than p-aminoclonidine greater than clonidine = B-HT 920 greater than rilmenidine. For alpha-2 antagonists, the potency order was: yohimbine greater than idazoxan greater than SK ampersand F-86,466 much greater than benextramine; (3) a description of the impact of benextramine (irreversible alpha-1/alpha-2 antagonist) on human fat cell alpha-2 adrenergic receptors and on human fat cell function; the drug inactivates the alpha-2 adrenergic receptors with a minor impact on beta adrenergic receptors and without noticeable alterations of fat cell function as assessed by preservation of beta adrenergic and Al-adenosine receptor-mediated lipolytic responses; and (4) a definition of the relationship existing between alpha-2 adrenergic receptor occupancy, inhibition of adenylate cyclase activity and antilipolysis with full and partial agonists. The existence of a receptor reserve must be taken into account when evaluating alpha-2 adrenergic receptor distribution and regulation of human fat cells

  8. Integrated circuits with emitter coupling and their application in nanosecond nuclear electronics

    International Nuclear Information System (INIS)

    Basiladze, S.G.

    1976-01-01

    Principal static and dynamic characteristics are considered of integrated circuits with emitter coupling, as well as problems of signal transmission. Diagrams are given of amplifiers, discriminators, time interval drivers, generators, etc. Systems and units of nanosecond electronics employing integrated circuits with emitter coupling are briefly described

  9. Reduced Fragment Diversity for Alpha and Alpha-Beta Protein Structure Prediction using Rosetta.

    Science.gov (United States)

    Abbass, Jad; Nebel, Jean-Christophe

    2017-01-01

    Protein structure prediction is considered a main challenge in computational biology. The biannual international competition, Critical Assessment of protein Structure Prediction (CASP), has shown in its eleventh experiment that free modelling target predictions are still beyond reliable accuracy, therefore, much effort should be made to improve ab initio methods. Arguably, Rosetta is considered as the most competitive method when it comes to targets with no homologues. Relying on fragments of length 9 and 3 from known structures, Rosetta creates putative structures by assembling candidate fragments. Generally, the structure with the lowest energy score, also known as first model, is chosen to be the "predicted one". A thorough study has been conducted on the role and diversity of 3-mers involved in Rosetta's model "refinement" phase. Usage of the standard number of 3-mers - i.e. 200 - has been shown to degrade alpha and alpha-beta protein conformations initially achieved by assembling 9-mers. Therefore, a new prediction pipeline is proposed for Rosetta where the "refinement" phase is customised according to a target's structural class prediction. Over 8% improvement in terms of first model structure accuracy is reported for alpha and alpha-beta classes when decreasing the number of 3- mers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    International Nuclear Information System (INIS)

    Sardini, Paul; Angileri, Axel; Descostes, Michael; Duval, Samuel; Oger, Tugdual; Patrier, Patricia; Rividi, Nicolas; Siitari-Kauppi, Marja; Toubon, Hervé; Donnard, Jérôme

    2016-01-01

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as 226 Ra, are complicated to localize in geo-materials. Because of its high specific activity, 226 Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  11. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    Energy Technology Data Exchange (ETDEWEB)

    Sardini, Paul; Angileri, Axel [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Descostes, Michael [AREVA Mines, R& D Department, Paris (France); Duval, Samuel; Oger, Tugdual [AI4R SAS, Nantes (France); Patrier, Patricia [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Rividi, Nicolas [Service Camparis, Université Pierre et Marie Curie, Paris (France); Siitari-Kauppi, Marja [Radiochemistry Laboratory, University of Helsinki, Helsinki (Finland); Toubon, Hervé [AREVA Mines, R& D Department, Paris (France); Donnard, Jérôme [AI4R SAS, Nantes (France)

    2016-10-11

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as {sup 226}Ra, are complicated to localize in geo-materials. Because of its high specific activity, {sup 226}Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  12. Emittance growth in displaced, space-charge-dominated beams with energy spread

    International Nuclear Information System (INIS)

    Barnard, J.J.; Miller, J.; Haber, I.

    1993-01-01

    Conversion of transverse energy associated with the coherent motion of displaced beams into thermal energy, and thus emittance growth, has been predicted theoretically by a number of authors. Here, they authors show, using 2-D particle-in-cell simulations, that emittance growth is inhibited for tune depressed beams, if the energy spread of the beam is not too large. Further, using a uniform density model to calculate the space charge field of the beam, they numerically determine the criteria for emittance growth as a function of tune depression, energy spread, and beam displacement over a wide range of parameters. A theoretical interpretation of the results is presented. This study is applicable to an inertial fusion reactor driven by a heavy ion accelerator

  13. Total hemispherical emittance measured at high temperatures by the calorimetric method

    International Nuclear Information System (INIS)

    DiFilippo, F.; Mirtich, M.J.; Banks, B.A.; Stidham, C.; Kussmaul, M.

    1994-01-01

    A calorimetric vacuum emissometer (CVE) capable of measuring total hemispherical emittance of surfaces at elevated temperatures was designed, built, and tested. Several materials with a wide range of emittances were measured in the CVE between 773 to 923 K. These results were compared to values calculated from spectral emittance curves measured in a room temperature Hohlraum reflectometer and in an open-air elevated temperature emissometer. The results differed by as much as 0.2 for some materials but were in closer agreement for the more highly-emitting, diffuse-reflecting samples. The differences were attributed to temperature, atmospheric, and directional effects, and errors in the Hohlraum and emissometer measurements (± 5 percent). The probable error of the CVE measurements was typically less than 1 percent

  14. The effects of emitter-tied field plates on lateral PNP ionizing radiation response

    International Nuclear Information System (INIS)

    Barnaby, H.J.; Schrimpf, R.D.; Cirba, C.R.; Pease, R.L.; Fleetwood, D.M.; Kosier, S.L.

    1998-03-01

    Radiation response comparisons of lateral PNP bipolar technologies reveal that device hardening may be achieved by extending the emitter contact over the active base. The emitter-tied field plate suppresses recombination of carriers with interface traps

  15. Biologic data, models, and dosimetric methods for internal emitters

    International Nuclear Information System (INIS)

    Weber, D.A.

    1990-01-01

    The absorbed radiation dose from internal emitters has been and will remain a pivotal factor in assessing risk and therapeutic utility in selecting radiopharmaceuticals for diagnosis and treatment. Although direct measurements of absorbed dose and dose distributions in vivo have been and will continue to be made in limited situations, the measurement of the biodistribution and clearance of radiopharmaceuticals in human subjects and the use of this data is likely to remain the primary means to approach the calculation and estimation of absorbed dose from internal emitters over the next decade. Since several approximations are used in these schema to calculate dose, attention must be given to inspecting and improving the application of this dosimetric method as better techniques are developed to assay body activity and as more experience is gained in applying these schema to calculating absorbed dose. Discussion of the need for considering small scale dosimetry to calculate absorbed dose at the cellular level will be presented in this paper. Other topics include dose estimates for internal emitters, biologic data mathematical models and dosimetric methods employed. 44 refs

  16. Energy dependence of the emittance of damping ring beams

    International Nuclear Information System (INIS)

    Stiening, R.

    1985-01-01

    The energy at which the SLC damping rings are operated was chosen to be 1.21 GeV. At the time that that specification was made, the repetition rate of the SLC was expected to be 180 Hz. It is now anticipated that the repetition rate during the initial year of operation of the SLC will be 120 Hz. The following curves which show the output emittance of the damping rings as a function of input emittance and energy suggest that there is a range of energies over which the rings can be operated without changing the SLC luminosity. It should be noted that in the era of polarized beams, the damping ring energy will be fixed at the design value on account of the spin precession required in the LTR and RTL transport lines. The SLC design output emittance of the damping rings is 3 x 10 -5 radian-meters. Because of space charge disruption and quantum emission downstream of the damping rings, much lower values than the design value may not have a large beneficial effect on the luminosity. 3 figures

  17. Fowler Nordheim theory of carbon nanotube based field emitters

    Energy Technology Data Exchange (ETDEWEB)

    Parveen, Shama; Kumar, Avshish [Department of Physics, Jamia Millia Islamia (Central University), New Delhi (India); Husain, Samina [Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (Central University), New Delhi (India); Husain, Mushahid, E-mail: mush_reslab@rediffmail.com [Department of Physics, Jamia Millia Islamia (Central University), New Delhi (India)

    2017-01-15

    Field emission (FE) phenomena are generally explained in the frame-work of Fowler Nordheim (FN) theory which was given for flat metal surfaces. In this work, an effort has been made to present the field emission mechanism in carbon nanotubes (CNTs) which have tip type geometry at nanoscale. High aspect ratio of CNTs leads to large field enhancement factor and lower operating voltages because the electric field strength in the vicinity of the nanotubes tip can be enhanced by thousand times. The work function of nanostructure by using FN plot has been calculated with reverse engineering. With the help of modified FN equation, an important formula for effective emitting area (active area for emission of electrons) has been derived and employed to calculate the active emitting area for CNT field emitters. Therefore, it is of great interest to present a state of art study on the complete solution of FN equation for CNTs based field emitter displays. This manuscript will also provide a better understanding of calculation of different FE parameters of CNTs field emitters using FN equation.

  18. Nonlinear electrostatic emittance compensation in kA, fs electron bunches

    International Nuclear Information System (INIS)

    Geer, S.B. van der; Loos, M.J. de; Botman, J.I.M.; Luiten, O.J.; Wiel, M.J. van der

    2002-01-01

    Nonlinear space-charge effects play an important role in emittance growth in the production of kA electron bunches with a bunch length much smaller than the bunch diameter. We propose a scheme employing the radial third-order component of an electrostatic acceleration field, to fully compensate the nonlinear space-charge effects. This results in minimal transverse root-mean-square emittance. The principle is demonstrated using our design simulations of a device for the production of high-quality, high-current, subpicosecond electron bunches using electrostatic acceleration in a 1 GV/m field. Simulations using the GPT code produce a bunch of 100 pC and 73 fs full width at half maximum pulse width, resulting in a peak current of about 1.2 kA at an energy of 2 MeV. The compensation scheme reduces the root-mean-square emittance by 34% to 0.4π mm mrad

  19. Low Emittance Growth in a LEBT with Un-Neutralized Section

    Energy Technology Data Exchange (ETDEWEB)

    Prost, Lionel [Fermilab; Carneiro, Jean-Paul [Fermilab; Shemyakin, Alexander [Fermilab

    2016-06-01

    In a Low Energy Beam Transport line (LEBT), the emittance growth due to the beam's own space charge is typically suppressed by way of neutralization from either electrons or ions, which originate from ionization of the background gas. In cases where the beam is chopped, the neutralization pattern changes throughout the beginning of the pulse, causing the Twiss parameters to differ significantly from their steady state values, which, in turn, may result in beam losses downstream. For a modest beam perveance, there is an alternative solution, in which the beam is kept un-neutralized in the portion of the LEBT that contains the chopper. The emittance can be nearly preserved if the transition to the un-neutralized section occurs where the beam exhibits low transverse tails. This report discusses the experimental realization of such a scheme at Fermilab's PXIE, where low beam emittance dilution was demonstrated

  20. Refractometry characteristics of {alpha}-quartz after neutron irradiation; Refraktometrichaskie kharakteristiki {alpha}-kvartsa posle oblucheniya nejtronami

    Energy Technology Data Exchange (ETDEWEB)

    Abdkadyrova, I Kh [AN RU, Tashkent (Uzbekistan). Inst. Yadernoj Fiziki

    1997-02-01

    Lattice structure distortions in irradiated crystalline quartz were studied by refractometry methods. The refractometry constants of {alpha}-quartz for the flux of fast neutrons 10{sup 18} - 10{sup 21} neutron/cm{sup 2} were calculated. The critical kinetics of this constants at the phase transformation is observed.(author). 5 refs., 1 fig.