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Sample records for californium 252 target

  1. Californium-252 neutron sources

    International Nuclear Information System (INIS)

    Major production programs for the Savannah River reactors and the High Flux Isotopes Reactor at Oak Ridge have made 252Cf one of the most available and, at the USAEC's sales price of $10/μg, one of the least-expensive isotopic neutron sources. Reactor production has totaled approximately 2 g, and, based on expected demand, an additional 10 g will be produced in the next decade. The approximately 800 mg chemically separated to date has been used to prepare over 600 neutron sources. Most, about 500, have been medical sources containing 1 to 5 μg of 252Cf plated in needles for experimental cancer therapy studies. The remainder have generally been point sources containing 10 μg to 12 mg of oxide for activation, well logging, or radiography uses. Bulk sources have also been supplied to the commercial encapsulators. The latest development has been the production of 252Cf cermet wire which can be cut into almost contamination-free lengths of the desired 252Cf content. Casks are available for transport of sources up to 50 mg. Subcritical assemblies have been developed to multiply the source neutrons by a factor of 10 to 40, and collimators and thermalizers have also been extensively developed to shape the neutron flux and energy distributions for special applications. (U.S.)

  2. Californium-252 Neutron Sources for Medical Applications

    International Nuclear Information System (INIS)

    Californium-252 neutron sources are being prepared to investigate the value of this radionuclide in diagnosing and treating diseases. A source resembling a cell-loaded radium needle was developed for neutron therapy. Since therapy needles are normally implanted in the body, very conservative design criteria were established to prevent leakage of radioactive. Methods are being developed to prepare very intense californium sources that could be used eventually for neutron radiography and for diagnosis by neutron activation analysis. This paper discusses these methods

  3. Californium-252: a remarkable versatile radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Osborne-Lee, I.W.; Alexander, C.W.

    1995-10-10

    A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

  4. Californium-252: a remarkable versatile radioisotope

    International Nuclear Information System (INIS)

    A product of the nuclear age, Californium-252 (252Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, 252Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of 252Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the 252Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, 252Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of 252Cf from ORNL is summarized herein

  5. Historical review of californium-252 discovery and development

    International Nuclear Information System (INIS)

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving 252Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed

  6. Californium-252 Neutron Therapy in China

    International Nuclear Information System (INIS)

    Californium-252 brachytherapy, believed to be the most successful source for neutron therapy, gives most of the cures as well as long-term and complication-free survivals. Chinese radiation oncologists were interested in californium neutron therapy (Cf-NT) in the early 1980s, but 252Cf sources for medical use were not available in China until 1992 when a californium joint venture was established by the China Institute of Atomic Energy (Beijing) and the Research Institute for Nuclear Reactors (Dimitrovgrad) of Russia. In 1995, 25 seeds of 252Cf with a strength of 3 μg each were sent to China for preclinical investigation. Three years later, a high dose rate (HDR) 252Cf source was imported and transferred into a home-made remote after-loader for intracavitary treatment in Chongqing, and a clinical trail was started in February 1999. This is the first time that Cf-NT was performed for cancer patients in China. Since then, Cf-NT in China has developed rapidly. It is estimated that one-tenth of those radiation oncology centers with brachytherapy practice will be equipped with californium units in 5 yr. That means more than 30 units will be in use in hospitals. That is significant compared with other countries, but it is just one, on average, for each province or one per 40 million people in China. Progress also has been achieved in the 252Cf treatment delivery equipment. Preliminary clinical trails showed complete response observed in all cases treated, with a rapid clearance of tumors and mild reactions in normal tissues. The short-term results are quite encouraging. To deal with problems due to the demand for Cf-NT in China, attention should be paid to the following particulars: (1) A high-strength miniature source is needed for HDR/MDR interstitial therapy to extend the Cf-NT coverage. (2) Basic work on radiophysics and radiobiology needs to be done, including source calibration, clinical dosimetry, clinical RBE determination, and Cf-NT quality assurance

  7. Californium-252 sales and loans at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The production and distribution in the United States of 252Cf has recently been consolidated at the Oak Ridge National Laboratory (ORNL). The 252Cf Industrial Sales/Loan Program and the 252Cf University Load Program, which were formerly located at the Savannah River Plant (SRP), have been combined with the californium production and distribution activities of the Transuranium Element Production Program at ORNL. Californium-252 is sold to commercial users in the form of bulk californium oxide, palladium-californium alloy pellets, or alloy wires. Neutron source capsules, which are fabricated for loans to DOE or other US government agencies, are still available in all forms previously available. The consolidation of all 252Cf distribution activities at the production site is expected to result in better service to users. In particular, customers for neutrons sources will be ale to select from a wider range of neutron source forms, including custom designs, through a single contact point

  8. Californium-252 encapsulation at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    More than 1 g of the neutron-emitting isotope californium-252 has been encapsulated at SRL for worldwide medical, industrial, and research uses. Bulk sales packages have been prepared for the USDOE sales program since 1971. Doubly-encapsulated sources have been prepared for USDOE's market evaluation program since 1968. Californium-252 sources for loan and sales packages satisfy the criteria for Special Form Radioactive Material. Encapsulation is performed in special neutron-shielded containment facilities at SRL. Development of improved source and shipping package designs and processes is continuing. 17 figures

  9. Production, distribution and applications of californium-252 neutron sources

    International Nuclear Information System (INIS)

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 1011 neutrons s-1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations

  10. Production, distribution and applications of californium-252 neutron sources.

    Science.gov (United States)

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

  11. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  12. Prompt neutron spectrum of the spontaneous fission of californium-252

    International Nuclear Information System (INIS)

    The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

  13. On-line slurry analyses by californium-252

    International Nuclear Information System (INIS)

    In chemical processing technology on-line activation methods gain an increasing importance for process monitoring and control. A method is described according to which the different fluorspar contents at various strategic points of a flotation plant are determined through neutron activation by 100 μg californium-252. A continuous analytical system for onstream process control of slurries was designed and constructed. A compact facility, called SUSAC, allows continuous application of the method on an industrial scale. The main components of the SUSAC facility are the irradiation and measurement cells. The cells are equipped with multistage countercurrent stirrers ensuring a proper radial and vertical distribution of the sample. The hollow shaft of the stirrer of the irradiation cell houses the Cf-source. The NaI-detector has been installed in a recess in the bottom of the measuring cell. The volumes are 9 dm3 for the irradiation cell, 7.5 dm3 for the measuring cell, 1/2 dm3 for the vonnection line and 4 dm3 for feed and drainage lines including the pump. Investigations on the following topics are discussed: selection of stirrers, residence time, flow rate, pulp density, calibration measurements. (T.G.)

  14. Proposed Californium-252 User Facility for Neutron Science at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The Radiochemical Engineering Development Center (REDC) at ORNL has petitioned to establish a Californium-252 User Facility for Neutron Science for academic, industrial, and governmental researchers. The REDC Californium Facility (CF) stores the national inventory of sealed 252Cf neutron source for university and research loans. Within the CF, the 252Cf storage pool and two uncontaminated hot cells currently in service for the Californium Program will form the physical basis for the User Facility. Relevant applications include dosimetry and experiments for neutron tumor therapy; fast and thermal neutron activation analysis of materials; experimental configurations for prompt gamma neutron activation analysis; neutron shielding and material damage studies; and hardness testing of radiation detectors, cameras, and electronics. A formal User Facility simplifies working arrangements and agreements between US DOE facilities, academia, and commercial interests

  15. Study of the shielding for spontaneous fission sources of Californium-252

    International Nuclear Information System (INIS)

    A shielding study is made to attenuate, until maximum permissible levels, the neutrons radiation and photons emitted by spontaneous fission coming from a source of Californium-252. The compound package by a database (Library DLC-23) and the ANISNW code is used, in it version for personal computer. (Author)

  16. Californium (252Cf) and its use as neutron source in science medicine and technology

    International Nuclear Information System (INIS)

    The application of radionuclides in science and nuclear techniques basically is related to unstable isotopes, which are produced from stable elements in nuclear reactor. Their specifications are various from view point of application . Using of physical and chemical properties of radionuclides in chemistry, for with marking the organic compounds we can exactly explain the mechanism of chemical reactions in medical, biology and bio-chemistry. In these cases the behaviour of radionuclides is very important and the selection of the suitable radionuclides is determined between the elements for investigation aims. The special specification of radio-nuclides analysis such as, half-life, kind of ray and energy should be considered with an special accuracy as well as the laws security regulations from view point of ray-protection should be completely observed mean time working these radio-nuclides. It should be considered that application of radio-isotopes is very important from their special specifications point of view. Applying the radionuclides from technology point of view in sciences and nuclear techniques aren't only limited to three analyses of α, β, and γ, but we can use the share of neutron which are produced from spli ting of heavy nucleus such as Californium252 as a neutron source in the depths of the sea and also determining the concentration of low quantity elements on moon and other spheres. The radioisotope of Californium252 is a neutron useful radiator for investigation in nuclear medical and technology because of automatically rapid split to 3.2% Californium252 radiates 1.34 * 109N/m in each mil/GH which suitable replacement for neutron sources based on (a, n) reaction, for example, Radium-Brellium or Amersium-Brellium. The energy distribution of radiated neutrons from analyzing of Californium252 like the spectrum of neutron which is produced from splitting of U235, Pu239 nucleus has the maximum energy in quantity, En=1 MeV in the range of 1.5 MeV. The

  17. Survey of potential markets for devices using Californium-252

    International Nuclear Information System (INIS)

    Potential applications for devices or systems containing 252Cf in the years from 1975 to 1980 are estimated. The estimated number of devices and associated business value were derived from a survey of 46 industrial, educational and governmental organizations conducted from Jan. to May, 1975. Applications for devices and systems based on 252Cf are expected to increase by a factor of 7 in the 6-y period from 1975 to 1980. The annual business value of 252Cf devices should increase from 1.5 million dollars in 1975 to 10.8 million dollars in 1980. The potential European market should be several times as large as the US market, based on actual sales of 252Cf, which have been two to four times greater in Europe than in the US

  18. Californium-252 neutron activation facility at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    A neutron irradiation facility has been established to develop new analytical methods and for the support of research programs. A major component of this facility is a 252Cf source which provides both fission spectrum and thermal neutrons. (U.S.)

  19. Contribution to clinical dosimetry of californium 252 sources used at Gustave Roussy institute

    International Nuclear Information System (INIS)

    The main characteristics of californium 252 sources are presented in the first part of the report. Dose measurements around Californium sources were performed with a pair of ionization multiplication chambers: the first one has an Aluminium wall and is filled with Argon, the second one a plastic tissue-equivalent gas. A set of experiments was performed in order to investigate the relative influence of beta rays on the response of both chambers. Besides the experimental work a computer program was written to calculate the dose distribution around the actual sources made of a series of small active sources placed in catheters. Theoretical data around small sources can be found in the litterature. The comparison between experimental results and theoretical ones has shown a good agreement. The computer program will be included as a sub-routine in the more general computer program used for patients treated with interstitial therapy

  20. Design, construction, and characterization of a facility for neutron capture gamma ray analysis of sulfur in coal using californium-252

    International Nuclear Information System (INIS)

    A study of neutron capture gamma ray analysis of sulfur in coal using californium-252 as a neutron source is reported. Both internal and external target geometries are investigated. The facility designed for and used in this study is described. The external target geometry is found to be inappropriate because of the low thermal neutron flux at the sample location, which must be outside the biological shielding. The internal target geometry is found to have a sufficient thermal neutron flux, but an excessive gamma ray background. A water filled plastic facility, rather than the paraffin filled steel one used in this study, is suggested as a means of increasing flexibility and decreasing the beackground in the internal target geometry

  1. Californium-252 brachytherapy for anal and ano-rectal carcinoma

    International Nuclear Information System (INIS)

    Surgery has historically been the standard treatment for anal, ano-rectal and rectal carcinoma but is prone to local or regional failure. Over the past 15 years there has been increasing interest in and success with radiation therapy and combined chemoradiotherapy for treatment of anal and ano-rectal cancers. Cf-252 brachytherapy combined with external beam teletherapy has been investigated for anal and ano-rectal lesions at the Univ. of Kentucky with encouraging results

  2. Mobile equipment for neutron radiography using a californium-252 source

    International Nuclear Information System (INIS)

    The basic requirements for successful neutron radiography are first summarised and the use of 252Cf is placed in perspective by comparing its properties with those of sources based on the Be (γ, n) and Be (α, n) reactions which have a broadly similar range of applications. The more essential design features of mobile neutron radiography equipment are next examined in some detail, to show how the often conflicting requirements of optimum beam production and adequate shielding may be reconciled. An assembly with a maximum dimension around 1 m with a source of 1 mg is used as an example. The design data used are reproduced in graphical form to permit designs to be scaled to suit the source available and the requirements. The selection of suitable image recorders for 252Cf radiography is discussed with the conclusion that the gadolinium foil-film combinations are likely to remain the normal choice. Demonstration radiographs are presented with particular reference to the location of residual casting sand in gas-cooled turbine blades. Finally, it is suggested that other applications for mobile 252Cf-based neutron radiography equipment will be found in the ordnance, aero-space, chemical and nuclear fuel manufacturing industries. (author)

  3. Measurements of integral cross sections in the californium-252 fission neutron spectrum

    International Nuclear Information System (INIS)

    In a low-scattering arrangement cross sections averaged over the californium-252 spontaneous fission neutron spectrum were measured. The reactions 27Al(n,α)46Ti, 47Ti, 48Ti(n,p), 54Fe,56Fe(n,p), 58Ni(n,p), 64Zn(n,p), 115In(n,n') were studied in order to obtain a consistent set of threshold detectors used in fast neutron flux density measurements. Overall uncertainties between 2 and 2.5% could be achieved; corrections due to neutron scattering in source and samples are discussed

  4. Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

    International Nuclear Information System (INIS)

    Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs

  5. Automated absolute activation analysis with californium-252 sources

    Energy Technology Data Exchange (ETDEWEB)

    MacMurdo, K.W.; Bowman, W.W.

    1978-09-01

    A 100-mg /sup 252/Cf neutron activation analysis facility is used routinely at the Savannah River Laboratory for multielement analysis of many solid and liquid samples. An absolute analysis technique converts counting data directly to elemental concentration without the use of classical comparative standards and flux monitors. With the totally automated pneumatic sample transfer system, cyclic irradiation-decay-count regimes can be pre-selected for up to 40 samples, and samples can be analyzed with the facility unattended. An automatic data control system starts and stops a high-resolution gamma-ray spectrometer and/or a delayed-neutron detector; the system also stores data and controls output modes. Gamma ray data are reduced by three main programs in the IBM 360/195 computer: the 4096-channel spectrum and pertinent experimental timing, counting, and sample data are stored on magnetic tape; the spectrum is then reduced to a list of significant photopeak energies, integrated areas, and their associated statistical errors; and the third program assigns gamma ray photopeaks to the appropriate neutron activation product(s) by comparing photopeak energies to tabulated gamma ray energies. Photopeak areas are then converted to elemental concentration by using experimental timing and sample data, calculated elemental neutron capture rates, absolute detector efficiencies, and absolute spectroscopic decay data. Calculational procedures have been developed so that fissile material can be analyzed by cyclic neutron activation and delayed-neutron counting procedures. These calculations are based on a 6 half-life group model of delayed neutron emission; calculations include corrections for delayed neutron interference from /sup 17/O. Detection sensitivities of < or = 400 ppB for natural uranium and 8 ppB (< or = 0.5 (nCi/g)) for /sup 239/Pu were demonstrated with 15-g samples at a throughput of up to 140 per day. Over 40 elements can be detected at the sub-ppM level.

  6. Automated absolute activation analysis with californium-252 sources

    International Nuclear Information System (INIS)

    A 100-mg 252Cf neutron activation analysis facility is used routinely at the Savannah River Laboratory for multielement analysis of many solid and liquid samples. An absolute analysis technique converts counting data directly to elemental concentration without the use of classical comparative standards and flux monitors. With the totally automated pneumatic sample transfer system, cyclic irradiation-decay-count regimes can be pre-selected for up to 40 samples, and samples can be analyzed with the facility unattended. An automatic data control system starts and stops a high-resolution gamma-ray spectrometer and/or a delayed-neutron detector; the system also stores data and controls output modes. Gamma ray data are reduced by three main programs in the IBM 360/195 computer: the 4096-channel spectrum and pertinent experimental timing, counting, and sample data are stored on magnetic tape; the spectrum is then reduced to a list of significant photopeak energies, integrated areas, and their associated statistical errors; and the third program assigns gamma ray photopeaks to the appropriate neutron activation product(s) by comparing photopeak energies to tabulated gamma ray energies. Photopeak areas are then converted to elemental concentration by using experimental timing and sample data, calculated elemental neutron capture rates, absolute detector efficiencies, and absolute spectroscopic decay data. Calculational procedures have been developed so that fissile material can be analyzed by cyclic neutron activation and delayed-neutron counting procedures. These calculations are based on a 6 half-life group model of delayed neutron emission; calculations include corrections for delayed neutron interference from 17O. Detection sensitivities of 239Pu were demonstrated with 15-g samples at a throughput of up to 140 per day. Over 40 elements can be detected at the sub-ppM level

  7. Long-term effects of an intracavitary treatment with californium-252 on normal tissue

    International Nuclear Information System (INIS)

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with 252Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from 252Cf and 7000 rad from 226Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for 252Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from 252Cf and 5000 rad from 226Ra

  8. Five-year cure of cervical cancer treated using californium-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Female pelvic carcinoma is one of the common malignancies seen at the University of Kentucky Medical Center and often presents in an advanced stage. In 1976, the authors began to test californium-252 neutron brachytherapy (NT) for its efficacy for control of primary and recurrent advanced uterine, cervix, and vaginal cancers. The first protocol used was 5000-5500 rad of whole pelvis irradiation followed by 1-2 Cf-252 insertions using a single tandem placed in the utero-cervico-vaginal region. Of 27 patients with primary carcinomas treated, 10 are alive and well 5 year later (37%). Two of two recurrent tumors were locally controlled but failed later. These patients had advanced cervical, vaginal, or endometrial carcinomas. In 1977, a transitional year, treatment of only unfavorable stages and presentations with NT was initiated. Similar results were obtained with NT as compared to conventional photon therapy (PT). Further improvement in treatment results can be anticipated as NT brachytherapy is used for advanced cancer therapy by more effective treatment schedules and radiation doses. Cf-252 can be used as a radium substitute and achieved similar rates of tumor control and 5-year survivals. 21 references, 2 tables

  9. Oxygen enhancement ratio (OER) and therapeutic gain factor (GF) for californium-252 at low dose rate

    International Nuclear Information System (INIS)

    The potential benefit of the introduction of californium-252 in interstitial and intracavitary therapy is related to the greater efficiency of its neutron emission against anoxic cancer cells. In that respect, the oxygen enhancement ratio (OER) of the 252Cf emission has been determined for a continuous low dose rate irradiation. The biological system is growth inhibition in Vicia faba bean roots. A new Vicia faba ''BelB'' strain has been used, which better tolerates long periods (up to about 10 hours) of anoxia. In a first series of experiments, for a 252Cf (Dsub(n+γ)) dose rate of 0.11 Gy.h-1, an OER of 1.4+-0.1 was observed (the γ contribution Dγ to the total absorbed dose Dsub(n+γ) was 0.35 at the position of the root tips). In a second series of experiments, in somewhat different geometrical conditions with a 252Cf (Dsub(n+γ)) dose rate of 0.13 Gy.h-1, an OER of 1.5+-0.1 was observed (Dγ/Dsub(n+γ)=0.42). The OER values observed for similar irradiation times, with iridium-192 γ-rays, were 2.3+-0.2 and 2.6+-0.1 respectively, which leads to therapeutic gain factors (GF) of 1.6 and 1.7 respectively. These GF values are slightly lower than those previously obtained (GF=1.8) on the same system, with d(50)-Be p(75)-Be and 15 MeV neutron beams

  10. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    International Nuclear Information System (INIS)

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  11. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252

    International Nuclear Information System (INIS)

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U233 when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO2(NO3)4 and 18% of thorium Th(NO3)4 as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 107 s-1. In the design the value of the effective multiplication factor, whose value turned out keff <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  12. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

    International Nuclear Information System (INIS)

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55Mn (n.gamma)56 Mn, high concentration of manganese in the matrix and short half - life of 56Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56Fe(n,p)56Mn and 59 Co (n, α)56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  13. Feasibility and market potential of protein determination of wheat using californium-252

    International Nuclear Information System (INIS)

    To evaluate the feasibility of protein determination by capture gamma-ray analysis using californium-252 neutrons, an in-situ protein analysis system for use by grain handlers has been examined. Three 227 kilogram (approximately) lots of wheat were used to determine the amount of nitrogen present. Protein analyses by the Kjeldahl method were obtained from samples taken before and after the capture gamma-ray analyses. The 5.267-MeV gamma-ray was selected for use in this study as a compromise between efficiency and interference from other elements. The associated counting equipment was a multichannel analyzer with pulse shaping electronic and analysis computing equipment. A linear regression program was used to compare the regions of interest to the Kjeldahl protein averages. The counts composing each peak were summed and normalized using the total count of the hydrogen peak. The normalized nitrogen percentages indicate a significant correlation between the spectral regions and the Kjeldahl analyses. To a first approximation, the value of wheat is the wheat protein. At the present time, protein testing of wheat is destructive, cumbersome, and time-consuming as compared to the potential for capture gamma-ray analysis testing. Assuming that such a protein analysis unit can analyze 42 tonne of wheat per hour, over 120 units would be needed to monitor one-half the U.S. annual wheat production. A 0.5% improvement in processor realizations and grain throughput value of $167.00 per tonne will result in a projected savings of $150,000 per year per unit

  14. Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

    1976-01-01

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

  15. Uptake and distribution of californium-252 chloride administered intraperitoneally, intravenously or intratracheally and the effect of in vivo DTPA chelation on intratracheal instillation in the rat

    International Nuclear Information System (INIS)

    The first phase of this investigation, comprising of three groups of animals, was designed to study the fate of californium-252 chloride administered intraperitoneally, intravenously or intratracheally. The second phase, which consisted of two groups of animals, was designed to examine the effectiveness of DTPA chelation therapy in accelerating the excretion and preventing the deposition of californium-252 chloride instilled into the lungs of rats. Immediately following the dose administration of 2 uCi of californium-252 chloride which was dissolved in 0.2 ml of 0.9% NaCl at pH 3.5, each rat was placed in a metabolism cage. Each rat in the first group of phase II was given intraperitoneal injection of CaNa3 DTPA (50 mg/kg) and each rat in the second group was given intraperitoneal injections of 0.9% NaCl. Injections of the DTPA or the NaCl sham were initiated immediately after the intratracheal administration of californium-252 chloride and were continued every three days until sacrifice. Following intraperitoneal, intravenous or intratracheal administration, the whole body retention of californium as a function of time was described by a three component exponential equation. For each mode of administration the short term component exhibited a biological half-life of between 5 and 10 hours; the intermediate component between 4 and 6 days; and the long term component between 200 and 300 days. The organ data obtained following intraperitoneal and intravenous administration were indistinguishable. On day one, the liver retained about 9% of the administered dose and the kidneys retained 2.4%. Retention for these organs decreased to about 1% by day 32. The femurs maintained an almost constant level of 4.5% of the injected dose over the 32 days. The lungs, spleen, heart, and testes showed significant retention of californium

  16. Hypoxic versus normoxic external-beam irradiation of cervical carcinoma combined with californium-252 neutron brachytherapy. Comparative treatment results of a 5-year randomized study

    Czech Academy of Sciences Publication Activity Database

    Tačev, T.; Vacek, Antonín; Ptáčková, B.; Strnad, V.

    2005-01-01

    Roč. 181, č. 5 (2005), s. 273-284. ISSN 0179-7158 Institutional research plan: CEZ:AV0Z50040507 Keywords : cervical carcinoma * hypoxyradiotherapy * californium-252 Subject RIV: BO - Biophysics Impact factor: 3.490, year: 2005

  17. Metabolism and toxicity of californium

    International Nuclear Information System (INIS)

    Metabolism of californium can be compared with that of other transplutonium elements. The most important points are as follows: a fast blood clearance and fast bone uptake more important than liver uptake, a relatively high urinary excretion and kidney retention. Blood clearance of californium can be compared with that of americium. Distribution of californium 252 nitrate after intramuscular injection in rats was studied. There are very few experimental data on acute or long term toxicity of californium. (28 references)

  18. Multi-element neutron activation analysis of sediment using a californium-252 source

    International Nuclear Information System (INIS)

    The application of a 252Cf source to the neutron activation analysis of several elements in small (approximately 1.5 in. in dia) cores was studied using high-resolution gamma ray spectroscopy and manual data reduction. (U.S.)

  19. OER of californium-252 at low dose rate for growth inhibition in Vicia faba

    International Nuclear Information System (INIS)

    OER of 252Cf, at low dose rate, has been determined for growth inhibition in Vicia faba roots. A new strain ''BelB'' was used; it was found to be more resistant to prolonged anoxia. Two sets of linear 252Cf sources were used (linear activity 0.31 and 0.47 (μg.cm-1)) in somewhat different geometrical arrangements. The (n+γ) 252Cf dose rates at the level of the root tips were 0.11 and 0.13 Gy.h-1 respectively. The relative contribution of the γ component Dsub(γ) to the total absorbed dose Dsub(n+γ) at the level of the root tips was evaluated Dsub(γ)/Dsub(n+γ)=0.35 for the first source-geometry and 0.42 for the second source-geometry. The reference radiation was the γ emission of 192Ir, used in the same geometrical conditions and for similar irradiation times. Irradiations performed in aerobic and anoxic conditions were alternated. OER values of 1.4 +- 0.1 and 1.5 +- 0.1 were observed for the 252Cf emission with the first and second source-geometry respectively. The corresponding OER values for 192Ir were 2.3 +- 0.2 and 2.6 +- 0.1; the derived oxygen gain factors were then equal to 1.6 and 1.7 repectively

  20. Capture cross section measurement analysis in the Californium-252 spectrum with the Monte Carlo method

    International Nuclear Information System (INIS)

    Absolute average capture cross sections of gold, thorium, tantalum, molybdenum, copper and strontium in 252Cf spontaneous fission neutron spectrum were simulated for two types of experiment setups preformed by Z. Dezso and J. Csikai and by L. Green. The experiments were simulated with MCNP5 using cross section data from the ENDF/B-VII.0 library. The determination of neutron backscattering was calculated with the use of neutron flagging. Correction factors to experimentally measured values were determined to obtain average cross sections in a pure 252Cf spontaneous fission spectrum. Influence of concrete wall thickness, air moisture and room size on the average cross section was analyzed. Correction factors amounted to about 30%. Corrected values corresponding to average cross sections in a pure 252Cf spectrum were calculated for 197Au, 232Th, 181Ta, 98Mo, 65Cu and 84Sr. Average cross sections were also calculated with the RR-UNC software using IRDFF-v.1.05 and ENDF/B-VII.0 libraries. The revised average radiative capture cross sections are 75.5±0.1 mb for 197Au, 87.0±1.6 mb for 232Th , 98.0±4.5 mb for 181Ta, 21.2±0.5 mb for 98Mo, 10.3±0.3 mb for 63Cu, and 34.9±6.5 mb for 84Sr. - Highlights: • Average capture cross sections in 252Cf spontaneous fission spectrum were simulated. • Calculations were done using MCNP5 code and ENDF/B-VII.0 library. • Correction factors for self-shielding and room return effects were taken into account. • The revised average radiative capture cross sections for different materials are published

  1. Results with the electron cyclotron resonance charge breeder for the 252Cf fission source project (Californium Rare Ion Breeder Upgrade) at Argonne Tandem Linac Accelerator System

    International Nuclear Information System (INIS)

    The construction of the Californium Rare Ion Breeder Upgrade, a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS), is nearing completion. The facility will use fission fragments from a 1 Ci 252Cf source; thermalized and collected into a low-energy particle beam by a helium gas catcher. In order to reaccelerate these beams, an existing ATLAS electron cyclotron resonance (ECR) ion source was redesigned to function as an ECR charge breeder. Thus far, the charge breeder has been tested with stable beams of rubidium and cesium achieving charge breeding efficiencies of 9.7% into 85Rb17+ and 2.9% into 133Cs20+.

  2. Application of SCGE assay, classical cytogenetics and FISH for studying in vitro californium-252 neutrons irradiations and BSH pretreatment on human lymphocytes

    International Nuclear Information System (INIS)

    Recently, there has been observed a tendency to apply various energy neutrons for tumor therapy and particularly low energy neutrons from various sources, including californium-252 source, for cancer radiotherapy based on the neutron capture. In this study peripheral blood lymphocytes were used as a model for human cells and three methods were applied to assess the effectiveness of californium-252 neutrons irradiations in vitro in normal cells or pre-treated with compound enriched in B-10 ion. Human blood samples or isolated lymphocytes were irradiated with neutrons from isotopic 252Cf source at the Faculty of Nuclear Physics and Technics at University of Mining and Metallurgy (both neutron source and samples were placed in polyethylene block). Chemical pretreatment with BSH (Na210B12H11SH) was done to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Comet assay was done to investigate the DNA damage. Classical cytogenetics was applied to assess the frequencies of unstable aberrations (dicentrics and rings). Fluorescence in situ hybridization (FISH) with probes for chromosomes 1, 4 (14.3% of whole genome) and pancentromeric probe was performed to evaluate the frequencies of stable aberrations. Linear (or close to linear) increase of DNA damage and aberration frequency was observed with dose of radiation both for lymphocytes untreated or pre-treated with BSH. Very little differences (statistically insignificant) due to radiation dose and BSH pretreatment were observed in the frequencies of SCEs detected in the second mitosis. There is no significant difference between boron pre-treated and not treated cells, and even slightly higher effects were observed in case of the highest dose without BSH pretreatment. The level of translocations observed is comparable with the frequencies of dicentrics and rings. (author)

  3. Anatomy of a controversy: Application of the Langevin technique to the analysis of the Californium-252 Source-Driven Noise Analysis method for subcriticality determination

    International Nuclear Information System (INIS)

    The expressions for the power spectral density of the noise equivalent sources have been calculated explicitly for the (a) stochastic transport equation, (b) the one-speed transport equaton, (c) the one-speed P1 equations, (d) the one-speed diffusion equation and (e) the point kinetic equation. The stochastic nature of Fick's law in (d) has been emphasized. The Langevin technique has been applied at various levels of approximation to the interpretation of the Californium-252 Source-Driven Noise Analysis (CSDNA) experiment for determining the reactivity in subcritical media. The origin of the controversy surrounding this method has been explained. The foundations of the CSDNA method as a viable experimental technique to infer subcriticality from a measured ratio of power spectral densities of the outputs of two neutron detectors and a third external source detector has been examined by solving the one-speed stochastic diffusion equation for a point external Californium-252 source and two detectors in an infinite medium. The expression relating reactivity to the measured ratio of PSDs was found to depend implicitly on k itself. Through a numerical analysis fo this expression, the authors have demonstrated that for a colinear detector-source-detector configuration for neutron detectors far from the source, the expression for the subcritical multiplication factor becomes essentially insensitive to k, hence, demonstrating some possibility for the viability of this technique. However, under more realistic experimental conditions, i.e., for finite systems in which diffusion theroy is not applicable, the measurement of the subcritical multiplication factor from a single measured ratio of PSDs, without extensive transport calculations, remains doubtful

  4. Californium Electrodepositions at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boll, Rose Ann [ORNL

    2015-01-01

    Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory (ORNL) during the past year involving two different types of deposition solutions, ammonium acetate (NH4C2H3O2) and isobutanol ((CH3)2CHCH2OH). A californium product that was decay enriched in 251Cf was recovered for use in super-heavy element (SHE) research. This neutron-rich isotope, 251Cf, provides target material for SHE research for the potential discovery of heavier isotopes of Z=118. The californium material was recovered from aged 252Cf neutron sources in storage at ORNL. These sources have decayed for over 30 years, thus providing material with a very high 251Cf-to-252Cf ratio. After the source capsules were opened, the californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use in an accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Another deposition method, ammonium acetate, was used to produce a deposition containing 1.7 0.1 Ci of 252Cf onto a stainless steel substrate. This was the largest single electrodeposition of 252Cf ever prepared. The 252Cf material was initially purified using traditional ion exchange media, such as AG50-AHIB and AG50-HCl, and further purified using a TEVA-NH4SCN system to remove any lanthanides, resulting in the recovery of 3.6 0.1 mg of purified 252Cf. The ammonium acetate deposition was run with a current of 1.0 amp, resulting in a 91.5% deposition yield. Purification and handling of the highly radioactive californium material created additional challenges in the production of these sources.

  5. Californium Multiplier (CFX)

    International Nuclear Information System (INIS)

    The availability of 252Cf as an economical high-intensity neutron source has made it possible to construct compact neutron irradiation devices with widespread applications. The simplest such device consists of a single 252Cf source within a moderating and shielding medium. Higher neutron flux levels can be attained either through the use of more 252Cf or through source multiplication by means of a subcritical uranium assembly. Although the use of larger 252Cf sources to achieve higher neutron flux is technically straightforward, an economic penalty is paid as the source strength is increased. Larger californium sources imply larger initial investments to cover the cost of source material and larger operating costs resulting from the decay of the 252Cf source. A Californium Multiplier, the CFX, which produces a flux enhancement of 30 when compared to a conventional moderated 252Cf system has been designed, licensed, built, and tested by IRT Corporation. Such systems are now available on a commercial basis for both neutron radiography and neutron activation analysis. The first commercial CFX system was installed at the Research Laboratories of Eastman Kodak Company in Rochester, NY, in March 1975. This device, using 1 mg of 252Cf, is very stable and the neutron flux generated by the CFX is very reproducible. The performance characteristics of this system are summarized

  6. Biological Efficiency of Californium-252 Source Evaluated by Comet Assay, Classical Cytogenetics and FISH in Human Lymphocytes Irradiated without and with BSH Pretreatment

    International Nuclear Information System (INIS)

    Biological effectiveness of californium-252 source was evaluated after irradiations in vitro of normal or pre-treated with compound enriched in B-10 ion cells. Peripheral blood lymphocytes were used as a model for human cells. DNA and chromosomal damage were studied to compare biological effectiveness of irradiation. Human blood samples or isolated lymphocytes were irradiated with the isotopic source of 252Cf, at the Faculty of Physics and Nuclear Techniques at the University of Mining and Metallurgy (both neutron source and samples were placed in ''infinite'' polyethylene block). Chemical pretreatment with Na210B12H11SH (BSH) was performed to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Single cell gel electrophoresis also known as the Comet assay was done to investigate the DNA damage. Classical cytogenetic analysis was applied to assess the frequencies of unstable aberrations (dicentrics, rings and a centric fragments). To evaluate the frequencies of stable aberrations the fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 4 (14.3% of the whole genome) was performed. Linear (or close to linear) increase with radiation dose were observed for the DNA damage and aberration frequencies in lymphocytes both untreated or pre-treated with BSH. Levels of translocations evaluated for the whole genome were comparable with the frequencies of dicentrics and rings. No significant differences were detected due to radiation dose in the frequencies of sister chromatid exchanges (SCE) detected in the second mitosis. No statistically significant differences were observed in various biological end-points between normal or boron pre-treated cells. (author)

  7. Research and experimental work at Groote Schuur Hospital and the University of Cape Town using californium-252 sources

    International Nuclear Information System (INIS)

    Experiments have been undertaken to determine the high-LET and low-LET components of the absorbed dose from neutron beams. This is achieved by measuring the fluxes of the high-LET and low-LET radiations in a tissue-equivalent phantom individually and simultaneously using a scintillation probe fitted with a pulse shape discriminator. This system was successfully used with a 22 MeV neutron beam from the T(d,n) reaction and has been employed with 252Cf sources. Results obtained in the low-energy ranges (up to 3 MeV) indicate that the electron counts exceed the high-LET counts by a factor of 2 to 3. These results are related to the absorbed dose. Calculations have also been undertaken to establish whether the Paterson-Parker system could be used for the design of 252Cf treatments and the optimum needle activities to yield the desired dose. Experiments are under way to determine the variation of RBE and OER for 252Cf radiations around the source. The inhibition of root growth in Vicia Faba is being used to determine any such effects. Dose rates comparable to that employed in interstitial radiotherapy are being aimed at. A study of dose fractionation effects is also being undertaken. (author)

  8. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

    Energy Technology Data Exchange (ETDEWEB)

    Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: ce_delgado89@hotmail.com [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)

    2015-10-15

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  9. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source; Determinacao de manganes em minerios, por analise por ativacao, usando californio-252 como fonte de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Antonio

    1976-07-01

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction {sup 55}Mn (n.gamma){sup 56} Mn, high concentration of manganese in the matrix and short half - life of {sup 56}Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions {sup 56}Fe(n,p){sup 56}Mn and {sup 59} Co (n, {alpha}){sup 56} were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  10. Radiological Characterization Technical Report on Californium-252 Sealed Source Transuranic Debris Waste for the Off-Site Source Recovery Project at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-04-24

    This document describes the development and approach for the radiological characterization of Cf-252 sealed sources for shipment to the Waste Isolation Pilot Plant. The report combines information on the nuclear material content of each individual source (mass or activity and date of manufacture) with information and data on the radionuclide distributions within the originating nuclear material. This approach allows for complete and accurate characterization of the waste container without the need to take additional measurements. The radionuclide uncertainties, developed from acceptable knowledge (AK) information regarding the source material, are applied to the summed activities in the drum. The AK information used in the characterization of Cf-252 sealed sources has been qualified by the peer review process, which has been reviewed and accepted by the Environmental Protection Agency.

  11. The development and medical applications of a simple facility for partial body in vivo neutron activation analysis using californium-252 sources

    International Nuclear Information System (INIS)

    A simple and cheap facility for partial body neutron activation analysis has been designed, based on the use of two 100 μg 252Cf neutron sources. The results reported show that calcium can be measured in parts of the body such as the tibia with a precision as good as +- 1.6 % for a radiation dose of 2 rem. The uniformity of the thermal neutron flux density is better than +- 3 % over 10 cm. Some applications of this irradiation facility for studies of trace elements, in particular cadmium in liver and aluminium in liver or brain, have also been explored. However, the sensitivity attainable is not yet sufficient for the study of normal levels, but could be of interest in toxicological investigations

  12. Biomedical neutron research at the Californium User Facility for neutron science

    International Nuclear Information System (INIS)

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252Cf sources. Three projects at the CUF that demonstrate the versatility of 252Cf for biological and biomedical neutron-based research are described: future establishment of a 252Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy

  13. Biomedical neutron research at the Californium User Facility for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.C. [Oak Ridge National Lab., TN (United States); Byrne, T.E. [Roane State Community College, Harriman, TN (United States); Miller, L.F. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact {sup 252}Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with {sup 252}Cf sources. Three projects at the CUF that demonstrate the versatility of {sup 252}Cf for biological and biomedical neutron-based research are described: future establishment of a {sup 252}Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded {sup 252}Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy.

  14. Magnetism in californium

    International Nuclear Information System (INIS)

    A SQUID-based magnetic susceptometer has been constructed for studying small radioactive samples at temperatures below 350 K and in magnetic fields up to 50 kilogauss. The device has been used to study californium (element 98) in a number of solid-state forms: the dhcp metal, several oxides (Cf2O3 in both the bcc and monoclinic structures, Cf7O12, CfO2 and BaCfO3), several monopnictides (CfN, CfAs and CfSb) and the trichloride (in both the hexagonal and orthorhombic structures). All of these materials were studied in polycrystalline form, and hexagonal CfCl3 was studied in single-crystal form as well. The susceptometer has the sensitivity to measure samples containing less than 10 micrograms of californium. The magnetic susceptibilities of all of the californium materials at temperatures above about 100 K are described well by the Curie-Weiss relationship. This behavior is consistent with the assumption that the magnetic 5f electrons are localized and that the paramagnetic behavior can be interpreted in terms of the properties of the free ion. The measured values of the effective paramagnetic moment, μ/sub eff/, for all the californium materials that were studied are reasonably consistent with theoretical values based on intermediate coupling models. All of the californium materials showed some indications of cooperative magnetic effects. The dhcp metal was observed to order ferromagnetically at 52 K, and all of the californium compounds studied showed signs of antiferromagnetic ordering, mostly at temperatures below 25 K. 91 refs., 50 figs., 19 tabs

  15. Californium--palladium metal neutron source material

    Science.gov (United States)

    Dahlen, B.L.; Mosly, W.C. Jr.; Smith, P.K.; Albenesius, E.L.

    1974-01-22

    Californium, as metal or oxide, is uniformly dispersed throughout a noble metal matrix, provided in compact, rod or wire form. A solution of californium values is added to palladium metal powder, dried, blended and pressed into a compact having a uni-form distribution of californium. The californium values are decomposed to californium oxide or metal by heating in an inert or reducing atmosphere. Sintering the compact to a high density closes the matrix around the dispersed californium. The sintered compact is then mechanically shaped into an elongated rod or wire form. (4 claims, no drawings) (Official Gazette)

  16. Transuranium element production. II. Chemical processing of targets

    International Nuclear Information System (INIS)

    The chemical processing described concerns small experimental targets irradiated in OSIRIS or EL-III and industrial targets irradiated in the CELESTIN reactors. In view of the difficulties encountered when processing highly irradiated targets (760MWd.kg-1) by liquid-liquid extraction (interface sludges leading to stable emulsion) the new processes developed are based on inverse phase chromatography. This technique applied to targets of americium 241, plutonium 239 and a plutonium mixture rich in isotope 242 has given tens of milligrams of curium 242, grams of americium 243 and curium 244 and micrograms of californium 252

  17. The protective cell petrus for the production of californium 252

    International Nuclear Information System (INIS)

    The alpha, beta, gamma, neutron cell which is described in the present paper is devoted to the transplutonium element production and study. It is located at the CEN in Fontenay-aux-Roses (France). The 4 feet ordinary concrete shielding made of stacked blocs allows the manipulation of radioactive sources as high as 1000 curies of 1 MeV gamma rays and with a fast neutrons flux of 109 n.cm-2.s-1. The airtight alpha containment box is equipped with two transfer systems, one consists of a parallelepiped shaped airtight box located in a turntable, the other uses standard cylindrical containers made of polyethylene. The general equipment and the main setting up are also described. (authors)

  18. Production of extra pure curium and californium preparations

    International Nuclear Information System (INIS)

    Preparations of curium-244,245,248 and californium-249,252 are used for the production of ionizing radiation sources for different applications and fundamental nuclear-physical investigations, placing high requirements on the radiochemical and chemical purity of the preparations. Extraction chromatography using di-(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant was chosen to prepare extra pure curium and californium preparations. In order to identify the optimal conditions of Cm-Cf separation and to remove impurities from them (reagent and other impurities), investigations were performed into the effect of impurities (Na+, Ca2+, Al3+, Fe2+, Fe3+ taken as example), extractant and eluent concentration and solution flow rate on the efficiency of mutual purification of Cm and Cf. Both theoretical and experimental estimations were made of the maximum concentration at which the impurities do not affect the process. The conditions chosen allow mutual purification of milligram amounts of Cm and Cf from impurity elements at E(pur) =102 - 103 during a single chromatographic cycle (E(pur) =>103) using a column with 5 - 10 cm3 volume. In this case the production yield exceeds 98%. The purification of milligram amounts of curium and californium from fission products (lanthanides in general, cerium in particular) was performed in D2EHPA-decane-PbO2-HNO3 and D2EHPA-decane-DTPA-H3-Cit extraction chromatography systems. In order to establish the optimal conditions, the effect of [D2EHPA] and eluent on the mutual purification of Cm and Cf and on their purification from cerium and impurity elements was studied in the D2EHPA-decane-PbO2-HNO3 system. During a single chromatographic cycle the mutual purification factors of TPE and of their purification from impurity cations achieve 102-103, from cerium - E(pur) > 10. In the D2EHPA-decane-DTPA-H3Cit system, the effect of concentration of extractant and eluent pH on the efficiency of Cm and Cf purification from lanthanides was

  19. Californium Recovery from Palladium Wire

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  20. Spontaneous Partitioning of Californium from Curium: Curious Cases from the Crystallization of Curium Coordination Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cary, Samantha K.; Silver, Mark A.; Liu, Guokui; Wang, Jamie C.; Bogart, Justin A.; Stritzinger, Jared T.; Arico, Alexandra A.; Hanson, Kenneth; Schelter, Eric J.; Albrecht-Schmitt, Thomas E.

    2015-12-07

    The reaction of 248CmCl3 with excess 2,6-pyridinedicarboxylic acid (DPA) under mild solvothermal conditions results in crystallization of the tris-chelate complex Cm(HDPA)3·H2O. Approximately half of the curium remains in solution at the end of this process, and evaporation of the mother liquor results in crystallization of the bis-chelate complex [Cm(HDPA)- (H2DPA)(H2O)2Cl]Cl·2H2O. 248Cm is the daughter of the α decay of 252Cf and is extracted in high purity from this parent. However, trace amounts of 249,250,251Cf are still present in all samples of 248Cm. During the crystallization of Cm(HDPA)3·H2O and [Cm(HDPA)(H2DPA)(H2O)2Cl]Cl·2H2O, californium(III) spontaneously separates itself from the curium complexes and is found doped within crystals of DPA in the form of Cf(HDPA)3. These results add to the growing body of evidence that the chemistry of californium is fundamentally different from that of earlier actinides.

  1. Neutron activation analysis at the Californium User Facility for Neutron Science

    International Nuclear Information System (INIS)

    The Californium User Facility (CUF) for Neutron Science has been established to provide 252Cf-based neutron irradiation services and research capabilities including neutron activation analysis (NAA). A major advantage of the CUF is its accessibility and controlled experimental conditions compared with those of a reactor environment The CUF maintains the world's largest inventory of compact 252Cf neutron sources. Neutron source intensities of ≤ 1011 neutrons/s are available for irradiations within a contamination-free hot cell, capable of providing thermal and fast neutron fluxes exceeding 108 cm-2 s-1 at the sample. Total flux of ≥109 cm-2 s-1 is feasible for large-volume irradiation rabbits within the 252Cf storage pool. Neutron and gamma transport calculations have been performed using the Monte Carlo transport code MCNP to estimate irradiation fluxes available for sample activation within the hot cell and storage pool and to design and optimize a prompt gamma NAA (PGNAA) configuration for large sample volumes. Confirmatory NAA irradiations have been performed within the pool. Gamma spectroscopy capabilities including PGNAA are being established within the CUF for sample analysis

  2. Effects of 252Cf neutrons, transmitted through an iron block on human lymphocyte chromosome

    International Nuclear Information System (INIS)

    Chromosome aberration of human peripheral blood lymphocytes exposed to californium-252 (252Cf) neutrons transmitted through a 15 cm thick iron block was analysed. The spectrum of the filtered neutrons ranged from 0.1 to 2MeV with a peak at 0.7 MeV, simulating the Hiroshima atomic bomb neutron spectrum as shown in the Dosimetry System 1986 (DS86). Chromosome aberration frequencies after exposure to filtered and unfiltered 252Cf radiation were compared. Acentric ring chromosomes were significantly increased (p 0.1). The relative biological effectiveness (RBE) of the neutrons with respect to the formation of dicentrics and centric rings was 10.9 and 12.3 in the filtered and unfiltered conditions respectively, but the difference was not statistically significant. These results provide useful information for the re-evaluation of the biological effect of the Hiroshima atomic bomb radiations. (Author)

  3. Separation of 248Cm (III) from 252Cf (III) and its use in time resolved fluorescence spectroscopic (TRFS) studies

    International Nuclear Information System (INIS)

    The present report gives a description of the methodology for the separation of 248Cm(III) from decayed 252Cf (III) waste solution. The waste solution was first assayed for 252Cf content by neutron counting using a neutron well coincidence counter. The sample was subjected to the chemical separation of 248Cm (III) from 252Cf (III) following anion and cation exchange chromatography. The alpha spectrum of the separated curium fraction showed peaks due to 246Cm and 248Cm while the corresponding alpha spectrum of californium fraction showed 249,250,251,252Cf. The gamma ray abundances of 249Cf were determined with respect to its gamma rays of 387 keV and the data agreed well with that in literature. Separated Cm(III) was further characterized by recording its time resolved fluorescence spectrum (TRFS) in aqueous medium. (author)

  4. Test and evaluation results of the 252Cf shuffler at the Savannah River Plant

    International Nuclear Information System (INIS)

    The 252Cf Shuffler, a nondestructive assay instrument employing californium neutron source irradiation and delayed-neutron counting, was developed for measuring 235U content of scrap and waste items generated at the Savannah River Plant (SRP) reactor fuel fabrication facility. The scrap and waste items include high-purity uranium-aluminum alloy ingots as well as pieces of castings, saw and lathe chips from machining operations, low-purity items such as oxides of uranium or uranium intermixed with flux materials found in recovery operations, and materials not recoverable at SRP such as floor sweepings or residues from the uranium scrap recovery operation. The uranium contains about 60% 235U with the remaining isotopes being 236U, 238U, and 234U in descending order. The test and evaluation at SRP concluded that the accuracy, safety, reliability, and ease of use made the 252Cf Shuffler a suitable instrument for routine use in an industrial, production-oriented plant

  5. Operational experience with the Argonne National Laboratory Californium Rare Ion Breeder Upgrade facility and electron cyclotron resonance charge breeder

    Science.gov (United States)

    Vondrasek, R.; Clark, J.; Levand, A.; Palchan, T.; Pardo, R.; Savard, G.; Scott, R.

    2014-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory Argonne Tandem Linac Accelerator System (ATLAS) facility provides low-energy and accelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. A 350 mCi 252Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The ECR charge breeder has achieved stable beam charge breeding efficiencies of 10.1% for 23Na7+, 17.9% for 39K10+, 15.6% for 84Kr17+, and 12.4% for 133Cs27+. For the radioactive beams, a charge breeding efficiency of 11.7% has been achieved for 143Cs27+ and 14.7% for 143Ba27+. The typical breeding times are 10 ms/charge state, but the source can be tuned such that this value increases to 100 ms/charge state with the best breeding efficiency corresponding to the longest breeding times—the variation of efficiencies with breeding time will be discussed. Efforts have been made to characterize and reduce the background contaminants present in the ion beam through judicious choice of q/m combinations. Methods of background reduction are being investigated based upon plasma chamber cleaning and vacuum practices.

  6. Separation of californium from actinides and lanthanides in aqueous solution by electrochemical formation of amalgams

    International Nuclear Information System (INIS)

    The electrochemical reduction of transneptunium elements (Pu to Cf) and rare earths (Eu, Tm) from aqueous complexing solutions to amalgams was studied over a wide range of cathodic potentials in order to achieve optimal separation of californium. The reduction in acetate media (pH 4.5-4.6) at potentials around -1.7 to -1.9 V1 leads to a quantitative extraction of californium into the mercury phase, while more negative potentials are required for the reduction of the lighter transuranium elements and of the lanthanides. Hence, the optimal conditions for the separation of californium from the investigated actinides and lanthanides were determined. Separation factors α between 25 and 90 were found except in the case of Cf/Eu, where poor values (α varying from 7 to 12) were observed. More negative cathodic potentials decrease the selectivity of the reduction process. A similar study with lithium citrate solutions (pH ∝6) shows that satisfactory separation of californium from lighter and heavier actinides is achievable. A separation factor of 88 is obtained for Cf/Am at -1.98 V. The anodic stripping of mixed amalgams (Pu, Am, Cm, Bk, Tm and Cf) Hg in nitric and acetic acid soultions at potentials ranging from +0.1 to -0.7 V proceeds slowly and proved to be ineffective for the separation of californium from light actinides under conditions described. (orig.)

  7. The U.S. Department of Energy 252Cf program

    International Nuclear Information System (INIS)

    Soon after the discovery of the 252Cf radioisotope in 1952, researchers realized its potential as a spontaneous source of neutrons. Under the guidance of the Atomic Energy Commission, the Savannah River Laboratory (SRL) undertook an ambitious market evaluation and source fabrication program in the 1960s. Routine production of 252Cf was initiated at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL), initially from plutonium oxide target rods and ultimately from more productive recycle curium oxide target rods. The 252Cf radioisotope was then shipped to SRL for incorporation into a variety of SRL-designed sources for industrial, medical, and research applications. ORNL independently developed another line of sources, primarily for research applications. Industrial source fabrication operations were consolidated at ORNL in 1986. In 1992, SRL fabricated its last 252Cf sources. Today, most of the world's supply of 252Cf is processed, purified, and encapsulated for shipment at the Radiochemical Engineering Development Center (REDC) of ORNL

  8. Emergence of californium as the second transitional element in the actinide series.

    Science.gov (United States)

    Cary, Samantha K; Vasiliu, Monica; Baumbach, Ryan E; Stritzinger, Jared T; Green, Thomas D; Diefenbach, Kariem; Cross, Justin N; Knappenberger, Kenneth L; Liu, Guokui; Silver, Mark A; DePrince, A Eugene; Polinski, Matthew J; Van Cleve, Shelley M; House, Jane H; Kikugawa, Naoki; Gallagher, Andrew; Arico, Alexandra A; Dixon, David A; Albrecht-Schmitt, Thomas E

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence. PMID:25880116

  9. Fissile analysis of Hanford waste using Californium Multiplier/Delayed Neutron Counter system

    International Nuclear Information System (INIS)

    Measurement of low-level (10 ng/g or lower) fissile material (mainly plutonium) in Hanford waste and process samples is becoming increasingly important. A system has been designed consisting of a Californium Multiplier (CFX) and a Delayed Neutron Counter (DNC) to characterize these samples. This report describes hardware and analytical capability of the CFX/DNC system

  10. Neutrons flux distribution in a 252Cf irradiation cell for neutron activation analysis

    International Nuclear Information System (INIS)

    A 100 microgram Californium-252 (252Cf) neutron source was embedded in a pure paraffin moderator surrounded by neutron and gamma ray shields to be used as an irradiation cell facility for NAA experiments. The cell is provided with a direct horizontal channel and a Vertical Tangential Irradiation Channel (VTIC) that are parallel to the source axis. The cadmium difference method was used in determining the thermal and epithermal neutron flux distributions along the axis of the (VTIC). For this purpose, 10 pairs of bare and cadmium covered pure gold foils were irradiated at the same positions along the axis of the (VTIC) in two separate runs. The absolute efficiency of the HPGe detector at the gamma ray energy 411.8 keV of 198 Au, was found to be 0.0318 ± 0.0025.The obtained distributions of thermal and epithermal neutron fluxes were tabulated and graphically presented. An evidence for contributions from 252Cf fission by epithermal neutrons was noticed. As an application on this facility the concentration of gold in an ore sample from gold - bearing ivory vein of wady Allaqui (at south west of eastern desert) was determined. It was found to be 612 ± 6 ppm

  11. Safety Analysis Report for Packaging (SARP) of the Oak Ridge National Laboratory TRU Californium Shipping Container

    International Nuclear Information System (INIS)

    An analytical evaluation of the Oak Ridge National Laboratory TRU Californium Shipping Container was made in order to demonstrate its compliance with the regulations governing off-site shipment of packages that contain radioactive material. The evaluation encompassed five primary categories: structural integrity, thermal resistance, radiation shielding, nuclear criticality safety, and quality assurance. The results of this evaluation demonstrate that the container complies with the applicable regulations

  12. Emergence of californium as the second transitional element in the actinide series

    OpenAIRE

    Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; Stritzinger, Jared T.; GREEN, THOMAS D.; Diefenbach, Kariem; Cross, Justin N.; Knappenberger, Kenneth L.; Liu, Guokui; Silver, Mark A.; DePrince, A. Eugene; Polinski, Matthew J.; Van Cleve, Shelley M.; House, Jane H.; Kikugawa, Naoki

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resu...

  13. A new type-B cask design for transporting 252Cf

    International Nuclear Information System (INIS)

    A project to design, certify, and build a new US Department of Energy (DOE) Type B container for transporting >5 mg of 252Cf is more than halfway to completion. This project was necessitated by the fact that the existing Oak Ridge National Laboratory (ORNL) Type B containers were designed and built many years ago and thus do not have the records and supporting data that current regulations require. Once the new cask is available, it will replace the existing Type B containers. The cask design is driven by the unique properties of 252Cf, which is a very intense spontaneous fission neutron source and necessitates a large amount of neutron shielding. The cask is designed to contain up to 60 mg of 252Cf in the form of californium oxide or californium oxysulfate, in pellet, wire, or sintered material forms that are sealed inside small special-form capsules. The new cask will be capable of all modes of transport (land, sea, and air). The ORNL team, composed of technical and purchasing personnel and using rigorous selection criteria, chose NAC, International (NAC), as the subcontractor for the project. In January 1997, NAC started work on developing the conceptual design and performing the analyses. The original design concept was for a tungsten alloy gamma shield surrounded by two concentric shells of NS-4-FR neutron shield material. A visit to US Nuclear Regulatory Commission (NRC) regulators in November 1997 to present the conceptual design for their comments resulted in a design modification when the question of potential straight-line cracking in the NS-4-FR neutron shield material arose. NAC's modified design includes offset, wedgelike segments of the neutron shield material. The new geometry eliminates concerns about straight-line cracking but increases the weight of the packaging and makes the fabrication more complex. NAC has now completed the cask design and performed the analyses (shielding, structural, thermal, etc.) necessary to certify the cask. The cask

  14. Quantitative determination of 252Cf

    International Nuclear Information System (INIS)

    Sealed 252Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. The authors propose to use gamma-ray spectroscopy for such analysis. In particular, high-energy gamma rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. They have measured the gamma/alpha ratio for 252Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin 252Cf sources, alpha pulse height analysis, determination of alpha decay rate, and the measurement of gamma singles spectrum with a well shielded germanium spectrometer. The measured ratio and the gamma ray spectroscopy of unknown samples can provide the activity of 252Cf in these samples

  15. Quantitative determination of 252Cf

    International Nuclear Information System (INIS)

    Sealed 252Cf sources in the microCurie to milliCurie range are routinely used in industry and research. At present, no reliable analytical method is available for precise determination of the activity. Very strong sources can be analyzed by neutron counting but the error is large. We propose to use γ-ray spectroscopy for such analysis. In particular, high-energy γ rays (above 1 MeV) of fission fragments in equilibrium with the source are very convenient because they have little absorption in materials surrounding the source. It is found that the 1435.8-keV γ-ray of 138Cs and the 1596.5-keV γ-ray of 140La are well isolated and sufficiently above the background under these peaks. We have measured the γ/α ratio for the 252Cf with an uncertainty of better than 5%. The experiment involved the preparation of several thin 252Cf sources, alpha pulse height analysis, determination of α decay rate, and the measurement of γ singles spectrum with a well-shielded germanium spectrometer. The measured ratio and the γ-ray spectroscopy of unknown samples can provide the activity of 252Cf in these samples

  16. 14 CFR 252.13 - Small aircraft.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Small aircraft. 252.13 Section 252.13 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.13 Small aircraft. Air carriers shall prohibit smoking on...

  17. Graphite moderated (252)Cf source.

    Science.gov (United States)

    Sajo-Bohus, Laszlo; Barros, Haydn; Greaves, Eduardo D; Vega-Carrillo, Hector Rene

    2015-06-01

    The Thorium molten-salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid-fuel reactor. The neutron source to run this subcritical reactor is a (252)Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the (252)Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. PMID:25770393

  18. Graphite moderated 252Cf source

    International Nuclear Information System (INIS)

    The thorium molten salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid fuel reactor. The neutron source to run this subcritical reactor is a 252Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the 252Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. (Author)

  19. Radionuclide 252Cf neutron source

    International Nuclear Information System (INIS)

    Characteristics of radionuclide neutron sourses of 252Cf base with the activity from 106 to 109 n/s have been investigated. Energetic distributions of neutrons and gamma-radiation have been presented. The results obtained have been compared with other data available. The hardness parameter of the neutron spectrum for the energy range from 3 to 15 MeV is 1.4 +- 0.02 MeV

  20. Dicty_cDB: AFM252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available AF (Link to library) AFM252 (Link to dictyBase) - - - - AFM252P (Link to Original site) AFM252F 544 AFM...252Z 683 AFM252P 1207 - - Show AFM252 Library AF (Link to library) Clone ID AFM252 (Link... to dictyBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig - Original site URL http://dictycdb.biol.tsukuba.ac.jp/CSM/AF/AFM...2-C/AFM252Q.Seq.d/ Representative seq. ID AFM252P (Link to... Original site) Representative DNA sequence >AFM252 (AFM252Q) /CSM/AF/AFM2-C/AFM252Q.Seq.d/ AAAAAAATGCAAGATA

  1. Dicty_cDB: VHD252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VH (Link to library) VHD252 (Link to dictyBase) - - - Contig-U16379-1 VHD252P (Link to Original site) VHD2...52F 596 VHD252Z 740 VHD252P 1316 - - Show VHD252 Library VH (Link to library) Clone ID VHD2...e URL http://dictycdb.biol.tsukuba.ac.jp/CSM/VH/VHD2-C/VHD252Q.Seq.d/ Representative seq. ID VHD2...52P (Link to Original site) Representative DNA sequence >VHD252 (VHD252Q) /CSM/VH/VHD2-C/VHD2...KIYQ Homology vs CSM-cDNA Score E Sequences producing significant alignments: (bits) Value VHD252 (VHD252Q) /CSM/VH/VHD2-C/VHD2

  2. Dicty_cDB: SFC252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SF (Link to library) SFC252 (Link to dictyBase) - - - - SFC252P (Link to Original site) SFC252F ... ession in good prognostic human neuroblastoma upon comparison ... between good prognostic human neuroblastoma and po ...

  3. 7 CFR 3565.252 - Housing types.

    Science.gov (United States)

    2010-01-01

    ... housing must meet Agency requirements contained in 7 CFR part 1924, subpart A or a successor regulation... 7 Agriculture 15 2010-01-01 2010-01-01 false Housing types. 3565.252 Section 3565.252 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF...

  4. 7 CFR 252.3 - Administration.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Administration. 252.3 Section 252.3 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE... Administration. (a) Role of FNS. The Secretary will designate those commodities which will be available under...

  5. 46 CFR 252.13 - Contract.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Contract. 252.13 Section 252.13 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS AFFECTING SUBSIDIZED VESSELS AND OPERATORS OPERATING... Contract. Upon approval by the Board of an application for ODS, the applicant and the United States...

  6. 40 CFR 265.252 - Waste analysis.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Waste analysis. 265.252 Section 265... FACILITIES Waste Piles § 265.252 Waste analysis. In addition to the waste analyses required by § 265.13, the... in the pile to which it is to be added. The analysis conducted must be capable of...

  7. 14 CFR 252.9 - Ventilation systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC... as to provide the level and quality of ventilation specified and designed by the manufacturer for...

  8. 30 CFR 252.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Definitions. 252.2 Section 252.2 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OUTER CONTINENTAL SHELF (OCS) OIL... analyses of physical and chemical properties, logs or charts of electrical, radioactive, sonic, and...

  9. 24 CFR 221.252 - Substitute mortgagors.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 221.252... Cost Homes § 221.252 Substitute mortgagors. (a) Selling mortgagor. The mortgagee may effect the release... approval of a substitute mortgagor, as provided by this section. (b) Purchasing mortgagor. The...

  10. 48 CFR 252.217-7010 - Performance.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Performance. 252.217-7010... Clauses 252.217-7010 Performance. As prescribed in 217.7104(a), use the following clause: Performance (JUL..., scrap or other ship's material of the Government resulting from performance of the work as items...

  11. 42 CFR 2.52 - Research activities.

    Science.gov (United States)

    2010-10-01

    ... information: (1) Is qualified to conduct the research; (2) Has a research protocol under which the patient... of three or more individuals who are independent of the research project has reviewed the protocol... 42 Public Health 1 2010-10-01 2010-10-01 false Research activities. 2.52 Section 2.52...

  12. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Ostroumov, P. N., E-mail: ostroumov@anl.gov; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Pikin, A. I. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2015-08-15

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz.

  13. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    International Nuclear Information System (INIS)

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

  14. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source.

    Science.gov (United States)

    Ostroumov, P N; Barcikowski, A; Dickerson, C A; Perry, A; Pikin, A I; Sharamentov, S I; Vondrasek, R C; Zinkann, G P

    2015-08-01

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz. PMID:26329185

  15. SU-E-J-252: A Motion Algorithm to Extract Physical and Motion Parameters of a Mobile Target in Cone-Beam Computed Tomographic Imaging Retrospective to Image Reconstruction

    International Nuclear Information System (INIS)

    Purpose: A motion algorithm was developed to extract actual length, CT-numbers and motion amplitude of a mobile target imaged with cone-beam-CT (CBCT) retrospective to image-reconstruction. Methods: The motion model considered a mobile target moving with a sinusoidal motion and employed three measurable parameters: apparent length, CT number level and gradient of a mobile target obtained from CBCT images to extract information about the actual length and CT number value of the stationary target and motion amplitude. The algorithm was verified experimentally with a mobile phantom setup that has three targets with different sizes manufactured from homogenous tissue-equivalent gel material embedded into a thorax phantom. The phantom moved sinusoidal in one-direction using eight amplitudes (0–20mm) and a frequency of 15-cycles-per-minute. The model required imaging parameters such as slice thickness, imaging time. Results: This motion algorithm extracted three unknown parameters: length of the target, CT-number-level, motion amplitude for a mobile target retrospective to CBCT image reconstruction. The algorithm relates three unknown parameters to measurable apparent length, CT-number-level and gradient for well-defined mobile targets obtained from CBCT images. The motion model agreed with measured apparent lengths which were dependent on actual length of the target and motion amplitude. The cumulative CT-number for a mobile target was dependent on CT-number-level of the stationary target and motion amplitude. The gradient of the CT-distribution of mobile target is dependent on the stationary CT-number-level, actual target length along the direction of motion, and motion amplitude. Motion frequency and phase did not affect the elongation and CT-number distributions of mobile targets when imaging time included several motion cycles. Conclusion: The motion algorithm developed in this study has potential applications in diagnostic CT imaging and radiotherapy to extract

  16. ENEA results in the international comparison organized by BIPM for the measurament of neutron fluxes of a Californium source

    International Nuclear Information System (INIS)

    During the period between May 1978 and August 1984 under the auspices of Section III of CCEMRI of CIPM it has been carried out the international intercomparison of Californium neutron source emission rate. The previous intercomparison was based on Ra-Be (α -n) source measuraments, which took place between 1959 and 1965, and the results showed a total spread of +- 3%. Owing to the better accuracy achived over the following decade the Ra-Be intercomparison was no longer representative of the state of the art, therefore it was decided to arrange the intercomparison based on Californium which in the meantime reached a wide use in the world. Contributions to the intercomparison were received from fourteen laboratories representative of twelve Nations plus the BIPM. The results put into evidence a considerable advance on accuracy in the neutron source emission rate measuraments. The standard deviation of the residuals obtained from least square fit of normalized data resulted +- 0,57%. In the present report it is widely described the Manganese bath method used at ENEA, CRE Casaccia in Roma, and the experimental procedure followed for its absolute calibration. All measuraments are reported and analysed, including those effectuated for corrective factors determination. The final results obtained at ENEA for the circulated Californium source is (3,457 +- 0,013) 10*H7 neutron/s. The analysis of data from all partecipantes has been effectuated and concluded by J. Axton in March 1986 and the conclusions which have been showed in the present report put in evidence the satisfactory results achived by the ENEA

  17. 46 CFR 252.41 - Subsidy billing procedures.

    Science.gov (United States)

    2010-10-01

    ... 252, Title 46, CFR: and (c) the operation of the vessels covered by said Agreement and regulations... 46 Shipping 8 2010-10-01 2010-10-01 false Subsidy billing procedures. 252.41 Section 252.41... Payment and Billing Procedures § 252.41 Subsidy billing procedures. (a) Subsidy voucher—(1) Form....

  18. Experimental Dating of 252Cf Sources

    International Nuclear Information System (INIS)

    The gamma spectrum of a 252Cf neutron source holds a large number of peaks from the FP, their products and other Cf isotopes present in the spectrum. The differences between a new and an old 252Cf neutron source gamma spectrum are mainly in the size of 661, 388 and 177 keV peaks from 137Cs, 249Cf and 251Cf, respectively

  19. Neutron sources of palladium-252Cf oxide cermet wire

    International Nuclear Information System (INIS)

    Palladium-252Cf oxide cermet has been developed as a versatile, safe source form for 252Cf with low contamination potential. Developmental wire containing 1.85 mg of 252Cf has been sold in three orders to U. S. commercial encapsulators. Bare palladium-252Cf oxide cermet wire containing 252Cf concentrations of 5, 50, or 500 μg/in. is expected to be offered for general sale in the near future. (U.S.)

  20. Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii).

    Science.gov (United States)

    Dau, Phuong D; Shuh, David K; Sturzbecher-Hoehne, Manuel; Abergel, Rebecca J; Gibson, John K

    2016-08-01

    The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf(II) is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf(II)(CH3SO2)3(-), prepared in the gas phase by reductive elimination of CH3SO2 from Cf(III)(CH3SO2)4(-). Comparison with synthesis of the corresponding Sm and Cm complexes reveals reduction of Cf(III) and Sm(III), and no evidence for reduction of Cm(III). This reflects the comparative 3+/2+ reduction potentials: Cf(3+) (-1.60 V) ≈ Sm(3+) (-1.55 V) ≫ Cm(3+) (-3.7 V). Association of O2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. The new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf(II) coordination complexes and similar chemistry of Cf and Sm. PMID:27424652

  1. Solving the Hydration Structure of the Heaviest Actinide Aqua Ion Known: The Californium(III) Case

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, Ch.; Guillaumont, D. [CEA Marcoule, Nucl Energy Div, Radiochem Proc Dept, SCPS LILA, 30 (France); Galbis, E.; Pappalardo, Rafael R.; Marcos Sanchez, E. [Univ Seville, Dept Quim Fis, E-41012 Seville (Spain); Hernandez-Cobos, J. [Inst Ciencias Fis, Cuernavaca 62251, Morelos (Mexico); Le Naour, C.; Simoni, E. [Univ Paris Sud, Inst Phys Nucl Orsay, Paris (France)

    2010-07-01

    In summary, the first MC simulation of the trivalent cation of californium, based on an exchangeable hydrated ion-water intermolecular potential, has been shown to extend and improve the hydrated ion model. Likewise, the CfL{sub III}-edge EXAFS spectrum of an acidic 1 mm Cf(ClO{sub 4}){sub 3} aqueous solution recorded under optimized experimental conditions has greatly improved the signal/noise ratio of the only previously recorded spectrum. The comparison of the experimental EXAFS spectrum with the two computed ones, obtained from two different intermolecular potentials that predict eight (BP86) or nine (MP2) water molecules in the first coordination shell, leads to the conclusion that the lowest hydration number is preferred. Then, as Cf{sup III} is the heaviest actinide aqua ion for which there is experimental information, the actinide contraction is supported by the present study. (For U{sup III}, R{sub U-O}=2.56 Angstroms, and CN=9{+-}1; for Pu{sup III}, R{sub Pu-O}=2.51 Angstroms and CN=9{+-}1; for Cm{sup III}, R{sub Cm-O}=2.47 Angstroms and CN=9{+-}1). The role of the second hydration shell is important in defining the structure and dynamics of the Cf{sup III} aqua ion, but the contribution of second-shell water molecules to the EXAFS signal as back-scatters is marginal. Finally, this work gives an illustrative example of the benefits which can be achieved from the combination of experimental X-ray absorption spectroscopy and computer simulations. The usefulness of the simultaneous analysis of the results as well as the importance of the structural statistical average has been clearly demonstrated herein. Each technique independently was not adequate. We believe that this study traces out a still poorly explored combined methodology which may be extremely useful for many other complexes and chemical problems. A systematic theoretical and experimental examination of the other known actinide cations on the same basis should be undertaken to confirm the

  2. Integral range, energy, residual range, and linear energy transfer distributions for Californium fission fragments in microelectronics materials

    International Nuclear Information System (INIS)

    This report discusses the advantages and limitations of using Cf-252 radiation sources for single event testing of microelectronics for space environments. Integral distributions for the range, energy, residual range, and linear energy transfer of Cf-252 fission fragments in absorber and microelectronic materials have been calculated. Techniques are suggested for determining when single event testing using Cf-252 is appropriate; also, techniques are given for estimating the saturation cross section and thresh old linear energy transfer from test data. 10 refs., 25 figs., 2 tabs

  3. 252Cf encapsulation and shipping at SRL

    International Nuclear Information System (INIS)

    Techniques were developed at the Savannah River Laboratory to encapsulate 252Cf sources for research and for medical and industrial applications. The sources are for sale or loan under the USAEC market evaluation program. A new facility is described which limits radiation exposure rates to less than mrem/h in normally occupied areas, except for short periods when maximum amounts of up to 100 mg of 252Cf may be handled. Sources as large as 10 mg have been made in this facility. The entire complex is surrounded by up to 48 in. of gamma and neutron shielding. Equipment was designed for remote handling, assembly, and examination of microliter quantities of solutions and capsule components as small as 1/8-in. cylinders. Special equipment, procedures, and carriers are described for safe, practical handling, storage, and shipment of encapsulated 252Cf. Brief descriptions and photographs of six casks most commonly used for transporting quantities ranging from 100 μg to 50 mg of 252Cf are included. (U.S.)

  4. 27 CFR 25.252 - Records.

    Science.gov (United States)

    2010-04-01

    ... TREASURY LIQUORS BEER Removal of Brewer's Yeast and Other Articles § 25.252 Records. (a) Production. The brewer shall keep records of the production of malt syrup, wort, and other articles which are removed... of brewer's yeast, malt and other articles from the brewery. The record shall include the...

  5. Xe-135 Production from Cf-252

    Energy Technology Data Exchange (ETDEWEB)

    C. A. McGrath; T. P. Houghton; J. K. Pfeiffer; R. K. Hague

    2012-03-01

    135Xe is a good indicator that fission has occurred and is a valuable isotope that helps enforce the Comprehensive Test Ban Treaty. Due to its rather short half life and minimal commercial interest, there are no known sources where 135Xe can be purchased. Readily available standards of this isotope for calibrating collection and analytical techniques would be very useful. 135Xe can be produced in the fissioning of actinide isotopes, or by neutron capture on 134Xe. Since the neutron capture cross section of 134Xe is 3 mB, neutron capture is a low yield, though potentially useful, production route. 135Xe is also produced by spontaneous fission of 252Cf. 252Cf has a spontaneous fission rate of about 6 x 1011 s-1g-1. The cumulative yield from the spontaneous fission of 252Cf is 4.19%; and the competing neutron capture reaction that depletes 135Xe in thermal reactor systems is negligible because the neutron capture cross-section is low for fast fission neutrons. At the INL, scientists have previously transported fission products from an electroplated 252Cf thin source for the measurement of nuclear data of short-lived fission products using a technique called He-Jet collection. We have applied a similar system to the collection of gaseous 135Xe, in order to produce valuable standards of this isotope.

  6. 7 CFR 1951.252 - Definitions.

    Science.gov (United States)

    2010-01-01

    ....252 Definitions. Commercial classified. The Agency's highest quality Farm Credit Programs (FCP... family, and to service debts. The account is of such quality that commercial lenders would likely view...), Operating (OL), Soil and Water (SW), Recreation (RL), Emergency (EM), Economic Emergency (EE),...

  7. 6 CFR 25.2 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... part. SAFETY Act or Act—The term “SAFETY Act” or “Act” means the Support Anti-terrorism by Fostering... EFFECTIVE TECHNOLOGIES § 25.2 Definitions. Act of Terrorism—The term “Act of Terrorism” means any act..., procured, or sold for the purpose of preventing, detecting, identifying, or deterring acts of......

  8. 46 CFR 252.33 - Hull and machinery insurance.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Hull and machinery insurance. 252.33 Section 252.33... Subsidy Rates § 252.33 Hull and machinery insurance. (a) Subsidy items. The fair and reasonable net premium costs (including stamp taxes) of hull and machinery, increased value, excess general...

  9. 14 CFR 252.5 - Smoking ban: foreign air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Smoking ban: foreign air carriers. 252.5 Section 252.5 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.5 Smoking ban: foreign air carriers....

  10. 14 CFR 252.3 - Smoking ban: air carriers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Smoking ban: air carriers. 252.3 Section 252.3 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.3 Smoking ban: air carriers. Air...

  11. 48 CFR 252.246-7002 - Warranty of construction (Germany).

    Science.gov (United States)

    2010-10-01

    ... (Germany). 252.246-7002 Section 252.246-7002 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.246-7002 Warranty of construction (Germany). As prescribed in 246.710(4), use the following clause: Warranty of Construction (Germany) (JUN 1997) (a) In addition to any...

  12. 48 CFR 252.211-7003 - Item identification and valuation.

    Science.gov (United States)

    2010-10-01

    ... valuation. 252.211-7003 Section 252.211-7003 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.211-7003 Item identification and valuation. As prescribed in 211.274-6(a), use the following clause: Item Identification and Valuation (AUG 2008) (a) Definitions. As...

  13. 48 CFR 252.239-7013 - Obligation of the Government.

    Science.gov (United States)

    2010-10-01

    ... Government. 252.239-7013 Section 252.239-7013 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.239-7013 Obligation of the Government. As prescribed in 239.7411(c), use the following clause: Obligation of the Government (JUL 2006) (a) This basic agreement is not...

  14. 40 CFR 180.252 - Tetrachlorvinphos; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... residues. 180.252 Section 180.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.252 Tetrachlorvinphos; tolerances for residues. (a) General. Tolerances are established for...

  15. Graphite moderated {sup 252}Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Sajo B, L.; Barros, H.; Greaves, E. D. [Universidad Simon Bolivar, Nuclear Physics Laboratory, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of); Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    The thorium molten salt reactor is an attractive and affordable nuclear power option for developing countries with insufficient infrastructure and limited technological capability. In the aim of personnel training and experience gathering at the Universidad Simon Bolivar there is in progress a project of developing a subcritical thorium liquid fuel reactor. The neutron source to run this subcritical reactor is a {sup 252}Cf source and the reactor will use high-purity graphite as moderator. Using the MCNP5 code the neutron spectra of the {sup 252}Cf in the center of the graphite moderator has been estimated along the channel where the liquid thorium salt will be inserted; also the ambient dose equivalent due to the source has been determined around the moderator. (Author)

  16. Material recognition with a 252Cf source

    CERN Document Server

    Fabris, Daniela; Lunardon, Marcello; Moretto, Sandra; Nebbia, Giancarlo; Pesente, Silvia; Stevanato , Luca; Viesti, Giuseppe; Sajo-Bohusb, Laszlo

    2010-01-01

    Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged 252Cf source. Light elements (C,N,O) are identified by using the measured transmission versus neutron time of flight. The yield of the transmitted gamma ray as a function of energy provides high precision identification of the atomic number of the sample up to Z=83 . A tomography system, currently under construction, is described.

  17. Neutron shielding for a 252 Cf source

    International Nuclear Information System (INIS)

    To determine the neutron shielding features of water-extended polyester a Monte Carlo study was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through inelastic collisions and absorption reactions. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide production induced by neutron activation must be considered. In this investigation the Monte Carlo method was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252Cf isotopic neutron source. During calculations a detailed model for the 252Cf and the shield was utilized. To compare the shielding features of water extended polyester, the calculations were also made for the bare 252Cf in vacuum, air and the shield filled with water. For all cases the calculated neutron spectra was utilized to determine the ambient equivalent neutron dose at four sites around the shielding. In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. (Author)

  18. Efficiency of a 252Cf source in normal or in B-10 enriched lymphocytes evaluated by SCGE assay, classical cytogenetics and FISH technique

    International Nuclear Information System (INIS)

    Biological effectiveness of a californium-252 source was evaluated after irradiations in vitro of normal or pretreated cells with compound enriched in the B-10 ion (Na211B12H11SH also known as BSH) in order to check the possibility of any enhancement effect due to the process of boron neutron capture. Peripheral blood lymphocytes were used as a model for human cells. Human blood samples or isolated lymphocytes were irradiated with the isotopic source of 252Cf, at the Faculty of physics and Nuclear Techniques at the University of Mining and Metallurgy, Cracow (both the neutron source and the samples were placed in ''infinite'' polyethylene block). DNA and chromosomal damage were studied to compare the biological effectiveness of irradiation. Single cell gel electrophoresis also known as the Comet assay was done to investigate the DNA damage. Classical cytogenetic analysis was applied to assess the frequencies of unstable aberrations (dicentrics, rings and acentric fragments). To evaluate the frequencies of stable aberrations the fluorescence in situ hybridization (FISH) with probes for chromosomes 1, 4 (14.3% of the whole genome) was performed. Linear (or close to linear ) increases with radiation doses were observed for the DNA damage and aberration frequencies in lymphocytes both untreated or pretreated with BSH. Levels of translocations evaluated for the whole genome were comparable with the frequencies of dicentrics and rings. No significant differences were detected due to radiation dose in the frequencies of sister chromatid exchanges (SCE) detected in the second mitosis. Statistically no significant differences were observed in various biological end-points between normal or boron pre-treated cells. (author)

  19. 48 CFR 252.239-7006 - Tariff information.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Tariff information. 252... Provisions And Clauses 252.239-7006 Tariff information. As prescribed in 239.7411(a), use the following clause: Tariff Information (JUL 1997) (a) The Contractor shall provide to the Contracting Officer—...

  20. 48 CFR 252.229-7001 - Tax relief.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Tax relief. 252.229-7001... Clauses 252.229-7001 Tax relief. As prescribed in 229.402-70(a), use the following clause: Tax Relief (JUN 1997) (a) Prices set forth in this contract are exclusive of all taxes and duties from which the...

  1. Dicty_cDB: SHL252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available SH (Link to library) SHL252 (Link to dictyBase) - - - Contig-U10968-1 SHL252P (Link to Original ... e. 42 0.26 7 EC319940 |EC319940.1 EMBRYOF088886F18 POSSUM _01-POSSUM -C-EMBRYO-2KB Trichosurus vulpecula cDNA ...

  2. 50 CFR 665.252 - Harvest limitation program.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Harvest limitation program. 665.252... Fisheries § 665.252 Harvest limitation program. (a) General. Harvest guidelines for the Necker Island... catch of spiny and slipper lobsters. (2) Be expressed in terms of numbers of lobsters. (b)...

  3. Dicty_cDB: VSK252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VS (Link to library) VSK252 (Link to dictyBase) - - - Contig-U12592-1 VSK252P (Link to Original ... qilm vsykl*lenfklliqlmn*kellivliqmvlvqfqhni*nkflqh*vtl *hlkkqmn*lg ilipiemviflqmklqn*FFQNYNKPLANNGKKQKK--- ... qilm vsykl*lenfklliqlmn*kellivliqmvlvqfqhni*nkflqh*vtl *hlkkqmn*lg ilipiemviflqmklqn*FFQNYNKPLANNGKKQKK--- ...

  4. 48 CFR 252.241-7001 - Government access.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Government access. 252.241... Clauses 252.241-7001 Government access. As prescribed in 241.501-70(b), use the following clause: Government Access (DEC 1991) Authorized representatives of the Government may have access to the...

  5. 43 CFR 2.52 - Conduct of employees.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Conduct of employees. 2.52 Section 2.52 Public Lands: Interior Office of the Secretary of the Interior RECORDS AND TESTIMONY; FREEDOM OF... employee of the Department may disclose records subject to the Privacy Act unless disclosure is...

  6. 48 CFR 252.204-7006 - Billing Instructions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Billing Instructions. 252... Provisions And Clauses 252.204-7006 Billing Instructions. As prescribed in 204.7109, use the following clause: Billing Instructions (OCT 2005) When submitting a request for payment, the Contractor shall— (a)...

  7. 7 CFR 765.252 - Lease of security.

    Science.gov (United States)

    2010-01-01

    ... subpart G of 7 CFR part 1940. (c) Lease of chattel security. Lease of chattel security is not authorized... 7 Agriculture 7 2010-01-01 2010-01-01 false Lease of security. 765.252 Section 765.252 Agriculture... Lease of security. (a) Real estate leases. The borrower may lease real estate security provided...

  8. 48 CFR 252.217-7015 - Safety and health.

    Science.gov (United States)

    2010-10-01

    ... U.S.C. 651, et seq.); (b) The Safety and Health Regulations for Ship Repairing (29 CFR part 1915... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Safety and health. 252.217... Clauses 252.217-7015 Safety and health. As prescribed in 217.7104(a), use the following clause: Safety...

  9. Preparation of actinide targets by electrodeposition

    Science.gov (United States)

    Trautmann, N.; Folger, H.

    1989-10-01

    Actinide targets with varying thicknesses on different substrates have been prepared by electrodeposition either from aqueous solutions or from solutions of their nitrates in isopropyl alcohol. With these techniques the actinides can be deposited almost quantitatively on various backing materials within 15 to 30 min. Targets of thorium, uranium, neptunium, plutonium, americium, curium and californium with areal densities from almost carrier-free up to 1.4 mg/cm 2 on thin beryllium, carbon, titanium, tantalum and platinum foils have been prepared. In most cases, prior to the deposition, the actinides had to be purified chemically and for some of them, due to the limited amount of material available, recycling procedures were required. Applications of actinide targets in heavy-ion reactions are briefly discussed.

  10. Xe-135 production from Cf-252

    International Nuclear Information System (INIS)

    The presence of 135Xe is often used as an indicator that fission has occurred, and is used to help enforce the Comprehensive Test Ban Treaty. There are no known commercial suppliers, though it can be acquired. Readily available standards of this isotope are very useful. 135Xe can be produced through fission, or by neutron capture on 134Xe. At the INL, scientists have previously transported fission products from an electroplated 252Cf thin source for the measurement of nuclear data of short-lived fission products using a technique called He-Jet collection. A similar system has been applied to the collection of gaseous 135Xe, and 133Xe, in order to produce standards of these isotopes. (author)

  11. Ab initio full-potential study of mechanical properties and magnetic phase stability of californium monopnictides (CfN and CfP)

    Science.gov (United States)

    Amari, S.; Bouhafs, B.

    2016-09-01

    Based on the first-principles methods, the structural, elastic, electronic, properties and magnetic ordering of californium monopnictides CfX (X = P) have been studied using the full-potential augmented plane wave plus local orbitals (FP-L/APW + lo) method within the framework of density functional theory (DFT). The electronic exchange correlation energy is described by generalized gradient approximation GGA and GGA+U (U is the Hubbard correction). The GGA+U method is applied to the rare-earth 5f states. We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. In order to gain further information, we have calculated Young's modulus, shear modulus, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. The results mainly show that californium monopnictides CfX (X = P) have an antiferromagnetic spin ordering. Density of states (DOS) and charge densities for both compounds are also computed in the NaCl (B1) structure.

  12. System control for the modulated 252Cf source ''Shuffler''

    International Nuclear Information System (INIS)

    The design and theory of operation of the control chassis for a 252Cf nondestructive assay system are described. This system repetitively transfers a 252Cf source from the irradiation region to a shielded position before measuring the delayed neutrons. The design criteria for the system were: rapid movement and precise positioning of the 252Cf source, precise positioning of the sample, and very accurate timing of the irradiate and count cycles. To achieve these results crystal oscillators were used for timing, and stepping motors were used to position the sample and the source. (U.S.)

  13. True ternary fission of 252Cf

    International Nuclear Information System (INIS)

    Splitting of heavy radioactive nucleus into three fragments is known as ternary fission. If the size of the fragments are almost equal it is referred to as true ternary fission. Recently, Yu. V. Pyatkov et al observed/reported the experimental observation of true ternary fission in 252Cf. In this work, the possibilities of different true ternary fission modes of 252Cf through potential energy surface (PES) calculations based on three cluster model (TCM) are discussed. In TCM a condition on the mass numbers of the fission fragments is implied as A1 ≥ A2 ≥ A3 in order to avoid repetition of combinations. Due to this condition, the values of Z3 vary from 0 to 36 and Z2 vary from 16 to 51. Of the different pairs having similar (Z2, Z3) with different potential energy, a pair possessing minimum potential energy is chosen. Thus identified favourable combinations are plotted. For the PES calculations the arrangement of the fragments is considered in the order of A1+A2+A3. i.e. the heavy and the lightest fragments are kept at the ends. It is seen that the deepest minimum in the PES occurs for Z3=2 labelled as (Z2; 2) indicating He accompanied breakup as the most favourable one. Of which, the breakup with Z2 around 46 to 48 is the least (shown by dashed (Z1 = 50) and dotted (Z1 = 52) lines indicating a constant Z1 value). The other notable minima in the PES are labelled and they correspond to the (Z2, Z3) pairs viz., (20, 20), (28, 20), (28, 28) and (32, 32). Of these four minima, the first three are associated with the magic numbers 20 and 28. For Z3=20, there are two minimums at (20,20) and (28,20) among them (28,20) is the lowest minimum through which the minimum-path passes, and it is the ternary decay observed by Yu. V. Pyatkov et al. The fourth minima is the most interesting due to the fact that it corresponds to true ternary fission mode with Z2=32, Z3=32 and Z1=34. The minimum potential energy path also goes through this true ternary mode. The PES calculation

  14. An absolute measurement of #-v# of Cf252

    International Nuclear Information System (INIS)

    An absolute measurement of v of Cf252. An absolute determination of the average number of neutrons, #-v#, emitted in the spontaneous fission of Cf252 has been made by counting the fission neutrons in a large liquid scintillator. The detection efficiency of this counter was measured as a function of neutron energy. Well-collimated neutrons were scattered into the scintillator by an anthracene crystal, which detected the corresponding recoil protons. Pulse-shape discrimination was employed to eliminate γ-ray background. The detection efficiency for Cf252 fission neutrons was found to be 0.703 ± 0.007, giving a value of 3.78 ± 0.04 for the average number of prompt neutrons emitted per Cf252 fission. (author)

  15. 46 CFR 252.30 - Amount of subsidy payable.

    Science.gov (United States)

    2010-10-01

    ... OPERATORS OPERATING-DIFFERENTIAL SUBSIDY FOR BULK CARGO VESSELS ENGAGED IN WORLDWIDE SERVICES Calculation of..., as described separately in § 252.32. The daily ODS rate represents the cost differential between...

  16. Boron dose enhancement for Cf-252 brachytherapy

    International Nuclear Information System (INIS)

    Full text: Monte Carlo modelling of a Cf-252 source in water and in tissue has shown that there is a significant therapeutic advantage obtained if B-10 is present in the tumour cells. This study analyses the advantage in terms of therapeutic margin, defined as the distance from the border of the treatment volume where boron-loaded tumour cells will receive a therapeutic dose. Calculations were made with MCNP version 4a on a Pentium 60 MHz computer. Large voxel sizes allowed 70 minute runs to achieve statistical uncertainties of 5% or less for 100,000 source neutrons. Later runs with smaller voxels confirmed the accuracy of the initial calculations. Calculations were made for treatment volume radii up to 11 cm and 30 ppm boron-10. The therapeutic margin for radii in the range 3-9 cm is approximately 10% of the tumour radius. This results in a 30% increase in the volume inside which peripheral tumour cells may receive a therapeutic dose. The median therapeutic ratio within the therapeutic margin varied from 1.05 at 3 cm up to 1.25 at 10 cm. Thus there is little benefit for less advanced tumours with thickness less than 3 cm. However, cervical cancer frequently presents in an advanced state in Southeast Asia and in Aboriginal communities in Australia, partially attributable to low Pap smear screening rates. These conclusions support the development and testing of boron compounds in in vitro and in vivo models for cervical cancer

  17. Personnel exposure experience related to use of 252Cf sources

    International Nuclear Information System (INIS)

    Studies are presented of personnel exposures to 252Cf neutrons and gamma radiation during dosimetry experiments in mouse phantoms, fission foil detectors, and small tissue equivalent ionization chambers. Sensitivity of film badge emulsions to observed levels of 252Cf neutrons is discussed. Long-term personnel exposure histories are presented. Comparisons are made between neutron dose calculated from observed neutron-gamma ratios and the dose observed in neutron emulsions. Shielding used during experiments is described

  18. Bacterial community shift in the coastal Gulf of Mexico salt-marsh sediment microcosm in vitro following exposure to the Mississippi Canyon Block 252 oil (MC252)

    KAUST Repository

    Koo, Hyunmin

    2014-07-10

    In this study, we examined the responses by the indigenous bacterial communities in salt-marsh sediment microcosms in vitro following treatment with Mississippi Canyon Block 252 oil (MC252). Microcosms were constructed of sediment and seawater collected from Bayou La Batre located in coastal Alabama on the Gulf of Mexico. We used an amplicon pyrosequencing approach on microcosm sediment metagenome targeting the V3–V5 region of the 16S rRNA gene. Overall, we identified a shift in the bacterial community in three distinct groups. The first group was the early responders (orders Pseudomonadales and Oceanospirillales within class Gammaproteobacteria), which increased their relative abundance within 2 weeks and were maintained 3 weeks after oil treatment. The second group was identified as early, but transient responders (order Rhodobacterales within class Alphaproteobacteria; class Epsilonproteobacteria), which increased their population by 2 weeks, but returned to the basal level 3 weeks after oil treatment. The third group was the late responders (order Clostridiales within phylum Firmicutes; order Methylococcales within class Gammaproteobacteria; and phylum Tenericutes), which only increased 3 weeks after oil treatment. Furthermore, we identified oil-sensitive bacterial taxa (order Chromatiales within class Gammaproteobacteria; order Syntrophobacterales within class Deltaproteobacteria), which decreased in their population after 2 weeks of oil treatment. Detection of alkane (alkB), catechol (C2,3DO) and biphenyl (bph) biodegradation genes by PCR, particularly in oil-treated sediment metacommunity DNA, delineates proliferation of the hydrocarbon degrading bacterial community. Overall, the indigenous bacterial communities in our salt-marsh sediment in vitro microcosm study responded rapidly and shifted towards members of the taxonomic groups that are capable of surviving in an MC252 oil-contaminated environment.

  19. Investigation of the far asymmetric region in 252Cf(sf)

    Science.gov (United States)

    Hambsch, F.-J.; Oberstedt, S.

    1997-02-01

    A twin Frisch-gridded ionization chamber has been used to measure the fission fragment mass, kinetic-energy and angular correlations for 252Cf(sf). In total 2.5 × 10 8 events were collected. The focus was in the far asymmetric mass region, where enhancements in the yield had been found earlier. It could be shown, that these findings are due to false events, coming from either close geometries not properly taking into account the angular-dependent energy loss in the sample and backing, from a too large angular cone selected in case of studies employing ionization chambers, or even from poor target qualities.

  20. Investigation of the far asymmetric region in 252Cf(sf)

    International Nuclear Information System (INIS)

    A twin Frisch-gridded ionization chamber has been used to measure the fission fragment mass, kinetic-energy and angular correlations for 252Cf(sf). In total 2.5 x 108 events were collected. The focus was in the far asymmetric mass region, where enhancements in the yield had been found earlier. It could be shown, that these findings are due to false events, coming from either close geometries not properly taking into account the angular-dependent energy loss in the sample and backing, from a too large angular cone selected in case of studies employing ionization chambers, or even from poor target qualities. (orig.)

  1. Comet 252P/LINEAR: born (almost) dead?

    CERN Document Server

    Ye, Quan-Zhi; Wiegert, Paul A

    2016-01-01

    Previous studies have revealed Jupiter-family comet 252P/LINEAR as a comet that was recently transported into the near-Earth object (NEO) region in $\\sim1800$~AD yet only being weakly active. In this Letter, we examine the "formed (almost) dead" hypothesis for 252P/LINEAR using both dynamical and observational approaches. By statistically examining the dynamical evolution of 252P/LINEAR over a period of $10^7$~years, we find the median elapsed residency in the NEO region to be $4\\times10^2$~years which highlights the likelihood of 252P/LINEAR as an (almost) first-time NEO. With available cometary and meteor observations, we find the dust production rate of 252P/LINEAR to be at the order of $10^6$~kg per orbit since its entry to the NEO region. These two lines of evidence support the hypothesis that the comet was likely to have formed in a volatile-poor environment. Cometary and meteor observations during the comet's unprecedented close approach to the Earth around 2016 Mar. 21 would be useful for the understa...

  2. Isotopic yield in alpha accompanied ternary fission of 252Cf

    International Nuclear Information System (INIS)

    The cold ternary fission of 252Cf with 4He as light charged particle (LCP) is studied with fragments in the equatorial and collinear configuration, taking the interacting barrier as the sum of the Coulomb and proximity potential. The favorable fragment combinations are obtained from the cold valley plot and by calculating the yield for charge-minimized fragments. In both equatorial and collinear configurations, the highest yield is obtained for the fragment combination 116Pd + 4He + 132Sn, which possess doubly magic nuclei 132Sn(N = 82, Z = 50). The presence of doubly or near doubly magic nuclei (132Sn, 130Sn etc.) and higher Q value plays an important role in the alpha accompanied cold ternary fission of 252Cf. The comparison of the relative yield for equatorial configuration with that of collinear configuration, points to the fact that equatorial configuration is the preferred configuration for the LCP (4He) accompanied ternary fission in 252Cf isotope. The yields obtained for the alpha accompanied cold ternary fission of 252Cf in equatorial and collinear configuration are compared with the experimental data. The emission probability of long range alpha (LRA) particle from 252Cf isotope is predicted using our formalism and is found to be in agreement with experimental value. (author)

  3. Oxidation-reduction properties of americium, curium, berkelium, californium, einsteinium and fermium, and thermodynamic consequences for the 5f series

    International Nuclear Information System (INIS)

    The amalgamation of 5f elements from Am to Fm has been studied by using 241Am, 244Cm, 249Bk, 249Cf, 252Cf, 253Es, 254Es, 252Fm and 255Fm with two electrochemical methods, radiocoulometry and radiopolarography, perfectly adapted to investigate extremely diluted solutions when the concentration of electroactive species is as low as 10-16M. The theory of radiocoulometry has been developed in the general cases of reversible and irreversible electrode process. It has been used to interpret the experimental data on the kinetic curves of amalgamation, and to estimate the standard rate constant of the electrode process in complexing medium (citric). On the other hand the radiopolarographic method has been applied to study the mechanism of reduction at the dropping mercury electrode of cations M3+ in aqueous medium to the metal M with formation of amalgam. The results are exploited into two directions: 1- Acquisition of some data concerning the oxidation-reduction properties of elements from Am to Fm. Therefore the standard electrode E0 [M(III-0)] potentials for Bk, Cf and Es, and the standard electrode E0 [M(II-0)] potential for Fm are estimated and the relative stability of each oxidation state (from II to VII) of 5f elements is discussed; 2- Acquisition of unknown thermodynamic data on transcalifornium elements. Correlations between 4f and 5f elements are precised and some divergences appear for the second half of 4f and 5f series (i.e. for 65<=Z<=71 and 97<=Z<=103)

  4. Microscopic description of Cf-252 cold fission yields

    OpenAIRE

    Mirea, M.; Delion, D. S.; Sandulescu, A.

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioact...

  5. Theoretical analysis of the Cf-252 fission neutron spectrum

    International Nuclear Information System (INIS)

    A complex cascade evaporation model is used to analyse energy and angular distributions of Cf-252 fission neutrons for specified scission configurations. The sensitivity of the calculation with regard to the most important input data as well as certain approximations has been studied for typical fragment mass numbers. The paper includes a brief summary on the characteristics of the scission neutron component and its influence on energy spectra and angular distributions of fission neutrons. The model was also applied to calculate the distortion of the measurable Cf-252 fission neutron spectrum by the anisotropic fragment detection in time-of-flight spectrometer arrangements. (author)

  6. Dicty_cDB: SLC252 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available i*knfnr*l* fprtrmdscl*tcqsfh*klncqrsrstsycqtms**plalw**sinwfcc*splsfr*k deei**pkkrwsifk*lnliiii Homology vs ...Mus musculus 13 days embryo lung c... 176 5e-43 (Q8IU85) RecName: Full=Calcium/calmodulin-dependent protein ...kina... 176 5e-43 (Q8BW96) RecName: Full=Calcium/calmodulin-dependent protein kin...none) Dictyostelium discoideum chromoso... 192 6e-48 AB076903_1( AB076903 |pid:none) Ciona intestinalis Ci-Ca...SL (Link to library) SLC252 (Link to dictyBase) - - - Contig-U11996-1 SLC252Z (Link to Original

  7. Calculations of Nuclear Astrophysics and Californium Fission Neutron Spectrum Averaged Cross Section Uncertainties Using ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and Low-fidelity Covariances

    International Nuclear Information System (INIS)

    Nuclear astrophysics and californium fission neutron spectrum averaged cross sections and their uncertainties for ENDF materials have been calculated. Absolute values were deduced with Maxwellian and Mannhart spectra, while uncertainties are based on ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and Low-Fidelity covariances. These quantities are compared with available data, independent benchmarks, EXFOR library, and analyzed for a wide range of cases. Recommendations for neutron cross section covariances are given and implications are discussed

  8. Radioactive Beams from 252CF Fission Using a Gas Catcher and an ECR Charge Breeder at ATLAS

    CERN Document Server

    Pardo, Richard C; Hecht, Adam; Moore, Eugene F; Savard, Guy

    2005-01-01

    An upgrade to the radioactive beam capability of the ATLAS facility has been proposed using 252Cf fission fragments thermalized and collected into a low-energy particle beam using a helium gas catcher. In order to reaccelerate these beams an existing ATLAS ECR ion source will be reconfigured as a charge breeder source. A 1Ci 252Cf source is expected to provide sufficient yield to deliver beams of up to ~106 far from stability ions per second on target. A facility description, the expected performance and the expected performance will be presented in this paper. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract W-31-109-ENG-38.

  9. The 252Cf neutron spectrum in ISO Standard 8529

    International Nuclear Information System (INIS)

    The provenance of the 252Cf neutron spectrum tabulated in ISO Standard 8529 Part 1 is discussed in the light of queries raised in an earlier ESARDA article. It is shown that neither the ISO spectrum nor a Maxwellian representation is compatible with the most recent evaluation of this important standard spectrum.

  10. 48 CFR 252.225-7041 - Correspondence in English.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Correspondence in English... of Provisions And Clauses 252.225-7041 Correspondence in English. As prescribed in 225.1103(2), use the following clause: Correspondence in English (JUN 1997) The Contractor shall ensure that...

  11. 48 CFR 252.234-7002 - Earned Value Management System.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Earned Value Management... of Provisions And Clauses 252.234-7002 Earned Value Management System. As prescribed in 234.203(2), use the following clause: Earned Value Management System (APR 2008) (a) In the performance of...

  12. 48 CFR 252.237-7001 - Compliance with audit standards.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Compliance with audit... of Provisions And Clauses 252.237-7001 Compliance with audit standards. As prescribed in 237.270(d)(2), use the following clause: Compliance With Audit Standards (MAY 2000) The Contractor, in performance...

  13. 48 CFR 252.228-7001 - Ground and flight risk.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Ground and flight risk... of Provisions And Clauses 252.228-7001 Ground and flight risk. As prescribed in 228.370(b), use the following clause: Ground and Flight Risk (JUN 2010) (a) Definitions. As used in this clause— (1)...

  14. INAA using 252Cf neutron source at University of Pune

    International Nuclear Information System (INIS)

    The review presents the work done over last two decades on Instrumental Neutron Activation Analysis (INAA) by our research group at University of Pune using 252Cf spontaneous fission neutron source. The technique has been applied in different fields viz. numismatics, industry, agriculture, ayurveda, environmental and health sciences and diffusion studies. A brief discussion of the work is presented in this article. (author)

  15. 48 CFR 252.229-7002 - Customs exemptions (Germany).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Customs exemptions... of Provisions And Clauses 252.229-7002 Customs exemptions (Germany). As prescribed in 229.402-70(b), use the following clause: Customs Exemptions (Germany) (JUN 1997) Imported products required for...

  16. 48 CFR 252.228-7000 - Reimbursement for war-hazard losses.

    Science.gov (United States)

    2010-10-01

    ...-hazard losses. 252.228-7000 Section 252.228-7000 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.228-7000 Reimbursement for war-hazard losses. As prescribed in 228.370(a), use the following clause: Reimbursement for War-Hazard Losses (DEC 1991) (a) Costs...

  17. 48 CFR 252.229-7008 - Relief from import duty (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... (United Kingdom). 252.229-7008 Section 252.229-7008 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.229-7008 Relief from import duty (United Kingdom). As prescribed in 229.402-70(h), use the following clause: Relief from Import Duty (United Kingdom) (JUN...

  18. 48 CFR 252.216-7001 - Economic price adjustment-nonstandard steel items.

    Science.gov (United States)

    2010-10-01

    ...-nonstandard steel items. 252.216-7001 Section 252.216-7001 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.216-7001 Economic price adjustment—nonstandard steel items. As prescribed in 216.203-4-70(b), use the following clause: Economic Price Adjustment—Nonstandard Steel...

  19. 48 CFR 252.222-7004 - Compliance with Spanish social security laws and regulations.

    Science.gov (United States)

    2010-10-01

    ... Condition of the Enterprise) from the Ministerio de Trabajo y S.S., Tesoreria General de la Seguridad Social... social security laws and regulations. 252.222-7004 Section 252.222-7004 Federal Acquisition Regulations... PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.222-7004 Compliance with Spanish...

  20. 48 CFR 252.247-7023 - Transportation of supplies by sea.

    Science.gov (United States)

    2010-10-01

    ... by sea. 252.247-7023 Section 252.247-7023 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.247-7023 Transportation of supplies by sea. As prescribed in 247.573(b)(1), use the following clause: Transportation of Supplies by Sea (MAY 2002) (a) Definitions. As...

  1. 48 CFR 252.225-7037 - Evaluation of Offers for Air Circuit Breakers.

    Science.gov (United States)

    2010-10-01

    ... Air Circuit Breakers. 252.225-7037 Section 252.225-7037 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7037 Evaluation of Offers for Air Circuit Breakers. As prescribed in 225.7006-4(a), use the following provision: Evaluation of Offers for Air Circuit Breakers...

  2. 48 CFR 252.222-7005 - Prohibition on use of nonimmigrant aliens-Guam.

    Science.gov (United States)

    2010-10-01

    ... nonimmigrant aliens-Guam. 252.222-7005 Section 252.222-7005 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.222-7005 Prohibition on use of nonimmigrant aliens—Guam. As prescribed in 222.7302, use the following clause: Prohibition on Use of Nonimmigrant Aliens—Guam (SEP...

  3. 48 CFR 252.225-7031 - Secondary Arab boycott of Israel.

    Science.gov (United States)

    2010-10-01

    ... Israel. 252.225-7031 Section 252.225-7031 Federal Acquisition Regulations System DEFENSE ACQUISITION... of Provisions And Clauses 252.225-7031 Secondary Arab boycott of Israel. As prescribed in 225.7605, use the following provision: Secondary Arab Boycott of Israel (JUN 2005) (a) Definitions. As used...

  4. 48 CFR 252.234-7001 - Notice of Earned Value Management System.

    Science.gov (United States)

    2010-10-01

    ... Management System. 252.234-7001 Section 252.234-7001 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.234-7001 Notice of Earned Value Management System. As prescribed in 234.203(1), use the following provision: Notice of Earned Value Management System (APR 2008)...

  5. 48 CFR 252.225-7008 - Restriction on Acquisition of Specialty Metals.

    Science.gov (United States)

    2010-10-01

    ... of Specialty Metals. 252.225-7008 Section 252.225-7008 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7008 Restriction on Acquisition of Specialty Metals. As prescribed in 225.7003-5(a)(1), use the following clause: Restriction on Acquisition of Specialty Metals...

  6. 48 CFR 252.211-7004 - Alternate preservation, packaging, and packing.

    Science.gov (United States)

    2010-10-01

    ..., packaging, and packing. 252.211-7004 Section 252.211-7004 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.211-7004 Alternate preservation, packaging, and packing. As prescribed in 211.272, use the following provision: Alternate Preservation, Packaging, and Packing (DEC...

  7. 48 CFR 252.247-7021 - Returnable containers other than cylinders.

    Science.gov (United States)

    2010-10-01

    ... other than cylinders. 252.247-7021 Section 252.247-7021 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.247-7021 Returnable containers other than cylinders. As prescribed in 247.305-70, use the following clause: Returnable Containers Other Than Cylinders (MAY 1995)...

  8. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Samia de Freitas, E-mail: samiabrandao@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-06-15

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively, on the healthy tissue, on the balloon periphery and on the /{sub 1} and /{sub 2} tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h{sup -1}.p{sup -1}.s, respectively on the healthy tissue, on the target tumor and on the /{sub 1} and /{sub 2} infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  9. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    Directory of Open Access Journals (Sweden)

    Samia de Freitas Brandao

    2013-07-01

    Full Text Available Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results Intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the I 1 and I 2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the I 1 and I 2 infiltration zones. Conclusion Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones.

  10. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    International Nuclear Information System (INIS)

    Objective: comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and methods: simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted into biologically weighted dose rates. Results: intracavitary balloon catheter brachytherapy with I-125 produced biologically weighted mean dose rates of 3.2E-11, 1.3E-10, 1.9E-11 and 6.9E-13 RBE.Gy.h-1.p-1.s, respectively, on the healthy tissue, on the balloon periphery and on the /1 and /2 tumor infiltration zones. On the other hand, Cf-252 brachytherapy combined with BNCT produced a biologically weighted mean dose rate of 5.2E-09, 2.3E-07, 8.7E-09 and 2.4E-09 RBE.Gy.h-1.p-1.s, respectively on the healthy tissue, on the target tumor and on the /1 and /2 infiltration zones. Conclusion: Cf-252 brachytherapy combined with BNCT delivered a selective irradiation to the target tumor and to infiltration zones, while intracavitary balloon catheter brachytherapy with I-125 delivered negligible doses on the tumor infiltration zones. (author)

  11. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel-Design concept and experimental demonstration

    Science.gov (United States)

    Henzlova, D.; Menlove, H. O.; Rael, C. D.; Trellue, H. R.; Tobin, S. J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2016-01-01

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be orientation in the instrument.

  12. Microscopic description of Cf-252 cold fission yields

    CERN Document Server

    Mirea, M; Sandulescu, A

    2009-01-01

    We investigate the cold fission of 252Cf within the two center shell model to compute the potential energy surface. The fission yields are estimated by using the semiclassical penetration approach. It turns out that the inner cold valley of the total potential energy is strongly connected with Z=50 magic number. The agreement with experimental values is very much improved only by considering mass and charge asymmetry degrees of freedom. Thus, indeed cold fission of 252Cf is a Sn-like radioactivity, related the other two "magic radioactivities", namely alpha-decay and heavy-cluster decay, called also Pb-like radioactivity. This calculation provides the necessary theoretical confidence to estimate the penetration cross section in producing superheavy nuclei, by using the inverse fusion process.

  13. Regeneration in cervix cancer after 252Cf neutron brachytherapy

    International Nuclear Information System (INIS)

    Regeneration of clonogens in human cervical cancer was assessed by the pathological evaluation of the hysterectomy specimen after intracavitary 252Cf neutron brachytherapy implants separated by varying time intervals followed by extrafascial hysterectomy. In this study, patients with bulky/barrel shaped Stage IB cervical cancers received 252Cf implants plus approximately 45 Gy of whole pelvis linear accelerator radiotherapy in approximately 25 fractions in 5 weeks followed by hysterectomy 4-6 weeks after radiotherapy. The specimens were studied grossly and microscopically for residual tumor. It was found that the fraction of positive specimens increased with elapsed time interval between implants. These findings support the hypothesis that there is repopulation of surviving clonogens with increased time interval between the implants. The observation also supports current concerns that rapid depopulation of tumor can lead to rapid repopulation, that is, rapid shrinkage of tumor can alter the physiological environment such that clonogens can rapidly regenerate

  14. Determination of some elements using 252Cf source

    International Nuclear Information System (INIS)

    A description of determination of Al and Si in mountain rocks is given based on measurement of intensity of gamma-rays of 28Al (half-decay period 2.3 min) which is formed in reactions: 27Al(n,γ)28Al with thermal neutrons and 28Si(n,p)28Al (with fast neutrons). To activate samples, a 252Cf source has been used with a flux of (1.0+-0.1)x109 neutrons/sec. Induced gamma-radioactivity has been registered by an AI-128 analyser and NaI(Tl) sensor (40x40 mm) with a FEU-13 photo-electron multiplier and a cathode follower. The relative error of the method is 13% for Al and 18% for Si. The efficiency is 70 samples per day. Calculations have indicated that while using 252Cf it is possible to determine Na in rocks when its content is 10-4 g

  15. Evaluation of mass distribution data from 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    The mass distribution data of 252Cf spontaneous fission were evaluated based on 7 sets of available experimental data. The measured data were corrected for the standards and γ intensity used by using the new evaluated ones. The errors were made necessary adjusting. The evaluated experimental data were fitted with spline function without any restriction and with symmetric restriction. These two sets of fit data were recommended as reference data of the mass distribution of 252Cf spontaneous fission. The errors of the recommended data were considerably reduced comparing with the measured ones. The light and heavy peaks are not completely symmetric. Also there are fine structures on the right side of the light peak at A=109-111 and left side of the heavy peak at A=137-139. These should be paid attention and studied further. (author)

  16. A pneumatic transfer system for special form 252Cf

    International Nuclear Information System (INIS)

    A pneumatic transfer system has been developed for use with series 100 Special Form 252Cf. It was developed to reduce the exposure to personnel handling sources of 252Cf with masses up to 150 microg by permitting remotely activated two-way transfer between the storage container and the irradiation position. The pneumatic transfer system also permits transfers for reproducible repetitive irradiation periods. In addition to the storage container equipped with quick-release fittings, the transfer system consists of an irradiation station, a control box with momentary contact switches to activate the air-pressure control valves and indicators to identify the location of the source, and connecting air hose and electrical wire. A source of 20 psig air and 110 volt electrical power are required for operation of the transfer system which can be easily moved and set up by one individual in 5 to 10 minutes. Tests have shown that rarely does a source become lodged in the transfer tubing, but two methods have been developed to handle incomplete transfers of the 252Cf source. The first method consists of closing one air vent to allow a pressure impulse to propel the source to the opposite side. The second method applies to those 252Cf capsules with a threaded or tapped end to which a small ferromagnetic piece can be attached; an incompletely transferred source in the transfer tube can then be guided to a position of safety by surrounding the transfer tubing containing the capsule with a horseshoe magnet attached to the end of a long pole

  17. Investigation on 252Cf Fission Fragment Tracks in Polycarbonate Detectors

    Directory of Open Access Journals (Sweden)

    A. Bhattacharyya

    1992-10-01

    Full Text Available Registration and development of fission fragments emitted from /sup 252/Cf source have been carried out in three different polycarbonate detectors. The detectors have been characterised in terms of bulk etch rate and its behaviour. Maximum etchable cone lengths have been compared with the theoretically computed values. Identification of the fission fragments in terms of their mass and charge has been done with the help of the computer programme 'FFR'.

  18. Cure of cervical cancer using 252Cf neutron brachytherapy

    International Nuclear Information System (INIS)

    252Cf neutron brachytherapy was tested in a feasibility trial for efficacy for cervix cancer therapy vs. high stage radioresistant and subsequently for all stages of disease. Actuarial survival curves were analyzed for 218 patients treated between 1976 and 1983 and followed five to 14 years to the present time. A variety of doses, schedules and methods for brachytherapy was tested during this period, and a dose-response relationship for tumor eradication studied. All treatments were combined with whole-pelvis photon radiotherapy to approximately 45 to 60 Gy. This combination was found effective, particularly if an early implant schedule was used for the Cf implant, followed by whole-pelvis photon radiotherapy. For bulk/barrel shaped low-stage disease in medically fit patients, 252Cf implants were combined with surgery, i.e., extrafascial hysterectomy and was readily usable for treatment without complications and with high cure rates (92% five-year survival). All survivals and outcomes to 13 years match the best results of conventional photon radiotherapy. For all stages better results were observed for bulky, barrel, and advanced-stage tumors, especially for local tumor control, if optimal schedules, doses and implant numbers were used. Knowledge about neutron dose, dose per implant, number of implants and combination with photon beam therapy evolved during the trials. 252Cf represents a new quickacting effective radioisotope for human cancer therapy especially for treatment of radioresistant, bulky and high stage cancers. (orig.)

  19. Nuclear charge distribution in the spontaneous fission of 252Cf

    OpenAIRE

    Wang, Taofeng; Zhu, Liping; WANG, LIMING; Men, Qinghua; Han, Hongyin; Xia, Haihong

    2015-01-01

    The measurement for charge distributions of fragments in 252Cf has been performed by using a unique style of detector setup consisting of a typical grid ionization chamber and a dE-E particle telescope. We found that the fragment mass dependency of the average width of the charge distribution shows a systematic decreased trend with the obvious odd-even effect. The variation of widths of charge distribution with kinetic energies shows an approximate V-shape curve due to the large number of neu...

  20. Binary and ternary spontaneous fission of 252 Cf

    International Nuclear Information System (INIS)

    The high selectivity and sensitivity offered by large detector arrays such as GAMMASPHERE and EUROGAM enable one to identify several gamma-rays related to the binary and ternary spontaneous fission. The yields for Mo-Ba binary spontaneous fission were extracted again from the data with better statistics. A new experiment with the 252 Cf source has been done by using a Delta telescope and GAMMASPHERE arrays at Argonne National Laboratory. From these data and our older data, new relative alpha ternary spontaneous fission yields were extracted. These results and the emission of 10 Be in spontaneous fission and the existence of long lived nuclear molecule also will be discussed. (author)

  1. Terahertz Transmission Imaging with 2.52 THz Continuous Wave

    Institute of Scientific and Technical Information of China (English)

    Xiao-Tong Guan; De-Wei Zheng; Min Hu; Wen-Jie Fu; Yu-Meng Cui; Xiang Fan; Liang Zhang; Ye Yuan; Jing-Yuan Xu; Yuan Li

    2013-01-01

    In this article, two terahertz transmission imaging systems are built with a 2.52 THz continuous wave laser and two types of sensors. One is array scanning system using a 124×124 pyro-electric array camera as the detector; the other is a point-wise scanning system utilizing a Golay cell as the detector. The imaging speed and quality is briefly analyzed. Terahertz (THz) imaging results demonstrate that the array scanning system has higher imaging speed with lower resolution. The point-wise scanning system has higher imaging quality with lower speed.

  2. A 252Cf based nondestructive assay system for fissile material

    International Nuclear Information System (INIS)

    A modulated 252Cf source assay system 'Shuffler' based on fast-or-thermal-neutron interrogation combined with delayed-neutron counting has been developed for the assay of fissile material. The 252Cf neutron source is repetitively transferred from the interrogation position to a shielded position while the delayed neutrons are counted in a high efficiency 3He neutron well-counter. For samples containing plutonium, this well-counter is also used in the passive coincidence mode to assay the effective 240Pu content. The design of an optimized neutron tailoring assembly for fast-neutron interrogation using a Monte Carlo Neutron Computer Code is described. The Shuffler system has been applied to the assay of fuel pellets, inventory samples, irradiated fuel and plutonium mixed-oxide fuel. The system can assay samples with fissile contents from a few milligrams up to several kilograms using thermal-neutron interrogation for the low mass samples and fast-neutron interrogation for the high mass samples. Samples containing 235U-238U, or 233U-Th, or UO2-PuO2 fuel mixtures have been assayed with the Shuffler system. (Auth.)

  3. HIVAP calculations for the synthesis of new isotopes of Z=116 and Z=118 through 250Cm(48Ca, xn) and 250-252Cf(48Ca, xn) reactions

    International Nuclear Information System (INIS)

    The production and study of superheavy elements is an important area of research in contemporary experimental nuclear physics. The heaviest element produced so far is Z=118 (one isotope with A=294) in the 48Ca + 249Cf reaction with a production cross-section of 0.5 pico barns. Here we propose 250Cm(48Ca, xn) and 250-252Cf(48Ca, xn) reactions for the synthesis of heavier isotopes of Z=116 and 118 with comparable theoretical production cross-sections. 250Cm, 250Cf, 251Cf and 252Cf are feasible targets with half lives of 8300, 13.1, 898 and 2.6 years respectively

  4. 48 CFR 252.245-7000 - Government-furnished mapping, charting, and geodesy property.

    Science.gov (United States)

    2010-10-01

    ... mapping, charting, and geodesy property. 252.245-7000 Section 252.245-7000 Federal Acquisition Regulations..., charting, and geodesy property. As prescribed in 245.107-70, use the following clause: Government-Furnished Mapping, Charting, and Geodesy Property (DEC 1991) (a) Definition—Mapping, charting, and geodesy...

  5. 38 CFR 3.252 - Annual income; pension; Mexican border period and later war periods.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Annual income; pension; Mexican border period and later war periods. 3.252 Section 3.252 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity...

  6. 48 CFR 252.229-7010 - Relief from customs duty on fuel (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... on fuel (United Kingdom). 252.229-7010 Section 252.229-7010 Federal Acquisition Regulations System... (United Kingdom). As prescribed in 229.402-70(j), use the following clause: Relief from Customs Duty on Fuel (United Kingdom) (JUN 1997) (a) Pursuant to an agreement between the United States Government...

  7. 48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

    Science.gov (United States)

    2010-10-01

    ... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and...

  8. 48 CFR 252.225-7016 - Restriction on acquisition of ball and roller bearings.

    Science.gov (United States)

    2010-10-01

    ... of ball and roller bearings. 252.225-7016 Section 252.225-7016 Federal Acquisition Regulations System... and roller bearings. As prescribed in 225.7009-5, use the following clause: Restriction on Acquisition of Ball and Roller Bearings (MAR 2006) (a) Definitions. As used in this clause' (1)...

  9. 48 CFR 252.247-7024 - Notification of transportation of supplies by sea.

    Science.gov (United States)

    2010-10-01

    ... transportation of supplies by sea. 252.247-7024 Section 252.247-7024 Federal Acquisition Regulations System... supplies by sea. As prescribed in 247.574(c), use the following clause: Notification of Transportation of Supplies by Sea (MAR 2000) (a) The Contractor has indicated by the response to the solicitation...

  10. 48 CFR 252.247-7022 - Representation of extent of transportation by sea.

    Science.gov (United States)

    2010-10-01

    ... of transportation by sea. 252.247-7022 Section 252.247-7022 Federal Acquisition Regulations System... transportation by sea. As prescribed in 247.574(a), use the following provision: Representation of Extent of Transportation By Sea (AUG 1992) (a) The Offeror shall indicate by checking the appropriate blank in paragraph...

  11. 24 CFR 220.252 - Forbearance of foreclosure and assignment of mortgage.

    Science.gov (United States)

    2010-04-01

    ... assignment of mortgage. 220.252 Section 220.252 Housing and Urban Development Regulations Relating to Housing... COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MORTGAGE INSURANCE AND INSURED IMPROVEMENT LOANS FOR URBAN RENEWAL...

  12. 48 CFR 252.225-7038 - Restriction on Acquisition of Air Circuit Breakers.

    Science.gov (United States)

    2010-10-01

    ... of Air Circuit Breakers. 252.225-7038 Section 252.225-7038 Federal Acquisition Regulations System... Circuit Breakers. As prescribed in 225.7006-4(b), use the following clause: Restriction on Acquisition of Air Circuit Breakers (JUN 2005) Unless otherwise specified in its offer, the Contractor shall...

  13. 48 CFR 252.239-7016 - Telecommunications security equipment, devices, techniques, and services.

    Science.gov (United States)

    2010-10-01

    ...) Definitions. As used in this clause— (1) Securing means the application of Government-approved... security equipment, devices, techniques, and services. 252.239-7016 Section 252.239-7016 Federal... security equipment, devices, techniques, and services. As prescribed in 239.7411(d), use the...

  14. 48 CFR 252.222-7006 - Restrictions on the Use of Mandatory Arbitration Agreements.

    Science.gov (United States)

    2010-10-01

    ... Mandatory Arbitration Agreements. 252.222-7006 Section 252.222-7006 Federal Acquisition Regulations System... Arbitration Agreements. As prescribed in 222.7404, use the following clause: Restrictions on the Use of Mandatory Arbitration Agreements (MAY 2010) (a) Definitions. As used in this clause— Covered...

  15. 48 CFR 252.232-7011 - Payments in Support of Emergencies and Contingency Operations.

    Science.gov (United States)

    2010-10-01

    ... Emergencies and Contingency Operations. 252.232-7011 Section 252.232-7011 Federal Acquisition Regulations... Emergencies and Contingency Operations. As prescribed in section 232.908, use the following clause: PAYMENTS IN SUPPORT OF EMERGENCIES AND CONTINGENCY OPERATIONS (JUL 2010) (a) Definitions of pertinent...

  16. 48 CFR 252.227-7027 - Deferred ordering of technical data or computer software.

    Science.gov (United States)

    2010-10-01

    ... technical data or computer software. 252.227-7027 Section 252.227-7027 Federal Acquisition Regulations... data or computer software. As prescribed at 227.7103-8(b), use the following clause: Deferred Ordering of Technical Data or Computer Software (APR 1988) In addition to technical data or computer...

  17. 48 CFR 252.227-7026 - Deferred delivery of technical data or computer software.

    Science.gov (United States)

    2010-10-01

    ... technical data or computer software. 252.227-7026 Section 252.227-7026 Federal Acquisition Regulations... data or computer software. As prescribed at 227.7103-8(a), use the following clause: Deferred Delivery of Technical Data or Computer Software (APR 1988) The Government shall have the right to require,...

  18. 48 CFR 252.227-7019 - Validation of asserted restrictions-Computer software.

    Science.gov (United States)

    2010-10-01

    ... restrictions-Computer software. 252.227-7019 Section 252.227-7019 Federal Acquisition Regulations System...—Computer software. As prescribed in 227.7104(e)(3) or 227.7203-6(c), use the following clause: Validation of Asserted Restrictions—Computer Software (JUN 1995) (a) Definitions. (1) As used in this...

  19. 48 CFR 252.209-7007 - Prohibited Financial Interests for Lead System Integrators.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Prohibited Financial Interests for Lead System Integrators. 252.209-7007 Section 252.209-7007 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of...

  20. 48 CFR 252.208-7000 - Intent to furnish precious metals as Government-furnished material.

    Science.gov (United States)

    2010-10-01

    ... metals as Government-furnished material. 252.208-7000 Section 252.208-7000 Federal Acquisition... precious metals as Government-furnished material. As prescribed in 208.7305(a), use the following clause: Intent To Furnish Precious Metals as Government-Furnished Material (DEC 1991) (a) The Government...

  1. 48 CFR 252.225-7010 - Commercial Derivative Military Article-Specialty Metals Compliance Certificate.

    Science.gov (United States)

    2010-10-01

    ... Military Article-Specialty Metals Compliance Certificate. 252.225-7010 Section 252.225-7010 Federal... Military Article—Specialty Metals Compliance Certificate. As prescribed in 225.7003-5(b), use the following provision: Commercial Derivative Military Article—Specialty Metals Compliance Certificate (JUL 2009)...

  2. 48 CFR 252.236-7012 - Military construction on Kwajalein Atoll-evaluation preference.

    Science.gov (United States)

    2010-10-01

    ... Kwajalein Atoll-evaluation preference. 252.236-7012 Section 252.236-7012 Federal Acquisition Regulations... Kwajalein Atoll—evaluation preference. As prescribed in 236.570(c)(2), use the following provision: Military Construction on Kwajalein Atoll—Evaluation Preference (MAR 1998) (a) Definitions. As used in this provision—...

  3. Neutron beam experiments using nuclear research reactors: honoring the retirement of professor Bernard W. Wehring -II. 5. Testing Moderating Detection Systems with 252Cf-Based Reference Neutron Fields

    International Nuclear Information System (INIS)

    In recent years, Georgia Institute of Technology (Georgia Tech) has been involved in a number of neutron dosimetry research projects. Several reference neutron fields are now available for such projects. They are all based on the use of a 252Cf source. The source can be used by itself to create a reference un-moderated 252Cf neutron field, or it can be placed inside several different moderating assemblies. The spectra created by placing the source inside these assemblies and the un-moderated source are employed to investigate detector and dosimeter responses. Currently, the set of moderators available includes a 30-cm diam cadmium-covered D2O spherical shell, a 30-cm-thick iron spherical shell, a 30-cm-diam polyethylene spherical shell, an 18.3-cm-thick tungsten spherical shell, a 16-cm-thick lead spherical shell, and a 9-cm-thick tantalum spherical shell. In addition, the 252Cf source can be placed inside a neutron howitzer recently constructed at Georgia Tech. The howitzer is a WEP cylinder loaded with boron that has a 10.16-cm-diam cylindrical opening. When the source is placed in the cylindrical penetration of the howitzer, a neutron field ∼30 cm in diameter is created at a distance of 50 cm from the californium source. Over the last few years, Bonner sphere spectrometers using LiI(Eu) scintillators and LiF thermoluminescence dosimeters have been calibrated using this facility at Georgia Tech. Recently, the Neely Nuclear Research Center (NNRC) acquired an LB 6411 neutron probe (product of EG and G Berthold). This probe is designed to measure ambient dose equivalent in accordance with International Commission on Radiological Protection Publication 60 recommendations. It consists of a cylindrical 3He proportional counter surrounded by a 25-cm-diam spherical polyethylene moderator. Its neutron response is optimized for dose rate measurements of neutrons between thermal energies and 20 MeV (Ref. 5). As a test of the instrument's ability to measure ambient dose

  4. Brachytherapy of carcinoma of vulva with 252Cf

    International Nuclear Information System (INIS)

    Thirty patients with carcinoma of vulva were treated with interstitial neutron radiotherapy with 252Cf. Age of patients was from 32 to 83 years. Stage I was in I patient, stage II - in 12, stage III was in 10 patients. The diagnosis of vulvar cancer was made for the first time in 11 cases, 19 patients had recurrences after the initial treatment. Most of these patients also received external irradiation for cancer of vulva and bilateral inguinal sites with a single fraction dose of 2 Gy to a total dose 30-50 Gy. Enlarged inguinal lymph nodes were irradiated additionally to 60 Gy with reduced field of irradiation. When radiotherapy was used repeatedly interstitial brachytherapy comprised the major part of irradiation dose or the therapy was used alone delivering 35-55 iGy. We used 252Cf sources with increased activity at the ends 20-30 mm long. A number of inserted sources varied from 2 to 10, irradiation dose rate from 20.3 to 236.7 cGy/h, time of irradiation from 10.2 to 12. hours, RBE from 4.6 to 6.33. Special template device made it possible to implant sources in strictly pre-set geometry. Analysis of survival of patients showed that 2 years survival was 66%, 3 years - 60%, and 5 years survival was 49%. In two cases necrotic epithelitis developed with following radiation ulcer which were cured in 3-4 months. Clinical data showed great effectiveness of interstitial neutron therapy having in mind that 19 patients were treated for recurrences of vulvar cancer after previuos treatment

  5. The Extreme Type I Planetary Nebula M2-52

    Directory of Open Access Journals (Sweden)

    M. Peña

    2002-01-01

    Full Text Available Se presentan los resultados obtenidos a partir de espectroscopía de alta resolución de la parte central de la nebulosa planetaria bipolar M2-52 que muestra un tipo morfológico Br. Hemos confirmado que M2-52 es una nebulosa de Tipo I de Peimbert, con un espectro rico en líneas de alto y bajo grado de ionización y un fuerte enriquecimiento de He y N. La composición química del gas ionizado es: He/H = 0:165 0:010, O/H = (2:6 0:5 x 10_4, N/O = 2:3 0:3, Ne/O = 0:37 0:10, Ar/O = (9:2 2:0 x 10_3 y S/O > 2:0 x 10_3. La velocidad de expansión de la nebulosa es, en promedio, de 20 2 km s_1 y varía ligeramente dependiendo del ión considerado. Los iones de menor grado de ionización, N+ y S+, muestran vexp _ 18 km s_1, O++ y He+ muestran vexp _ 20 km s_1, en tanto que He++ y H+ muestran vexp _ 22 km s_1. Es posible que la zona de N+ y S+ esté siendo frenada por el anillo de material molecular encontrado alrededor de la estrella.

  6. Neutron Spectra, Fluence and Dose Rates from Bare and Moderated Cf-252 Sources

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-04-01

    A new, stronger 252Cf source (serial number SR-CF-3050-OR) was obtained from Oak Ridge National Laboratory (ORNL) in 2014 to supplement the existing 252Cf sources which had significantly decayed. A new instrument positioning track system was designed and installed by Hopewell Designs, Inc. in 2011. The neutron field from the new, stronger 252Cf source in the modified calibration environment needed to be characterized as well as the modified neutron fields produced by the new source and seven different neutron moderators. Comprehensive information about our 252Cf source, its origin, production, and isotopic content and decay characteristics needed to be compiled as well. This technical report is intended to address these issues.

  7. Development of high-activity 252Cf sources for neutron brachytherapy

    International Nuclear Information System (INIS)

    The Gershenson Radiation Oncology Center of Wayne State University (WSU), Detroit, Michigan, is using 252Cf medical sources for neutron brachytherapy. These sources are based on a 20-year-old design containing ≤ 30 microg 252Cf in the form of a cermet wire of Cf2O3 in a palladium matrix. The Radiochemical Engineering Development Center (REDC) of Oak Ridge National Laboratory has been asked to develop tiny high-activity 252Cf neutron sources for use with remote afterloading equipment to reduce treatment times and dose to clinical personnel and to expedite treatment of brain and other tumors. To date, the REDC has demonstrated that 252Cf loadings can be greatly increased in cermet wires much smaller than before. Equipment designed for hot cell fabrication of these wires is being tested. A parallel program is under way to relicense the existing source design for fabrication at the REDC

  8. Prompt Neutron Emission in 252CF Spontaneous Fission

    Science.gov (United States)

    Hambsch, F.-J.; Oberstedt, S.; Zeynalov, Sh.

    2011-10-01

    The prompt neutron emission in spontaneous fission of 252Cf has been investigated applying digital signal electronics. The goal was to compare the results from digital data acquisition and digital signal processing analysis with results of the pioneering work of Budtz-Jørgensen and Knitter. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213-equivalent neutron detector in total about 107 fission fragment-neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution, neutron time-of-flight and pulse shape have been investigated using a 12 bit waveform digitizer. The signal waveforms have been analyzed using digital signal processing algorithms. The results are in very good agreement with literature. For the first time the dependence of the number of emitted neutrons as a function of total kinetic energy (TKE) of the fragments is in very good agreement with theoretical calculations in the range of TKE from 140-220 MeV.

  9. Neutron emission in fission of 252Cf(sf)

    Science.gov (United States)

    Zeynalov, Sh.; Hambsch, F.-J.; Oberstedt, S.; Fabry, I.

    2009-10-01

    The prompt neutron emission in spontaneous fission of 252Cf has been investigated applying digital signal electronics. The goal was to compare the results of this digital data acquisition and digital signal processing analysis to the results of the pioneering work of Budtz-Jo/rgensen and Knitter. Using a twin Frisch-grid ionization chamber for fission fragment (FF) detection and a NE213 equivalent neutron detector in total about 10 neutron coincidences have been registered. Fission fragment kinetic energy, mass and angular distribution have been investigated using a 10 bit waveform digitizer. Neutron time- of- flight and pulse shape have been measured using analogue CAMAC modules, a 1 ns TDC and a pair of 12 bit charge-to-digital-converters. The fission fragment signals have been analyzed using digital signal processing algorithms. The results are in very good agreement with literature. For the first time the dependence of the number of neutrons as a function of total kinetic energy (TKE) of the fragments does not drop at low TKE.

  10. Nuclear charge distribution in the spontaneous fission of 252Cf

    CERN Document Server

    Wang, Taofeng; Wang, Liming; Men, Qinghua; Han, Hongyin; Xia, Haihong

    2015-01-01

    The measurement for charge distributions of fragments in 252Cf has been performed by using a unique style of detector setup consisting of a typical grid ionization chamber and a dE-E particle telescope. We found that the fragment mass dependency of the average width of the charge distribution shows a systematic decreased trend with the obvious odd-even effect. The variation of widths of charge distribution with kinetic energies shows an approximate V-shape curve due to the large number of neutron emission for the high excitation energies and cold fragmentation with low excitation energies. As for the behavior of the average nuclear charge with respect to its deviation {\\Delta}Z from the unchanged charge distribution (UCD) as a function of the mass number of primary fragments A*, for asymmetric fission products {\\Delta}Z is negative value, while upon approaching mass symmetry {\\Delta}Z turns positive. Concerning the energy dependence of the most probable charge for given primary mass number A*, the obvious inc...

  11. Functional design criteria for project W-252, phase II liquid effluent treatment and disposal. Revision 2

    International Nuclear Information System (INIS)

    This document is the Functional Design Criteria for Project W-252. Project W-252 provides the scope to provide BAT/AKART (best available technology...) to 200 Liquid Effluent Phase II streams (B-Plant). This revision (Rev. 2) incorporates a major descoping of the project. The descoping was done to reflect a combination of budget cutting measures allowed by a less stringent regulatory posture toward the Phase II streams

  12. Absolute measurements of anti ν (252Cf) using the manganese bath method

    International Nuclear Information System (INIS)

    By the manganese bath method and defined solid angle counting the fission rate anti ν (Cf-252) was measured. The corrections for neutrons losses due to leakage and absorption in the source itself and its surroundings were measured experimentally. The corrections for absorption fast neutrons on S and O was calculated by Monte-Carlo method. The obtained value of anti ν (Cf- 252) is 3.758+-0.015

  13. Role of antibiotic production by Erwinia herbicola Eh252 in biological control of Erwinia amylovora.

    OpenAIRE

    Vanneste, J L; Yu, J.; Beer, S V

    1992-01-01

    Erwinia herbicola Eh252 is a nonpathogenic epiphytic bacterium that reduces fire blight incidence when sprayed onto apple blossoms before inoculation with Erwinia amylovora, the causal agent of fire blight. Eh252 was found to produce on minimal medium an antibiotic that inhibited the growth of E. amylovora. This antibiotic was inactivated by histidine but not by Fe(II), was sensitive to proteolytic enzymes, and showed a narrow host range of activity. To determine the role of this antibiotic i...

  14. Prompt neutron multiplicity in correlation with fragments from spontaneous fission of 252Cf

    OpenAIRE

    GÖÖK Alf; Hambsch, Franz-Josef; Vidali, Marzio

    2014-01-01

    The spontaneous fission of 252Cf serves as an excellent benchmark of prompt emission in fission since experimental data can be obtained without the need of an incident beam. With the purpose of providing experimental data on the prompt fission neutron properties in correlation with fission fragment characteristics an experiment on 252Cf(SF) has been performed. In addition, the experiment serves as benchmark of setup and analysis procedures for measurements of fluctuations in the prompt neutro...

  15. Description of peculiarities of prompt fission neutron spectrum in spontaneous fission of 252Cr

    International Nuclear Information System (INIS)

    Full text : 252Cf is the model object in theoretical and experimental studying of prompt fission neutron spectrum in the both spontaneous and induced fission of heavy nuclei. However, the form of spectrum observed has not been clearly understood especially in the region of lower and higher energies. The last compiled data are frequently used as a standart for the test of theoretical prescriptions of the neutron spectrum in spontaneous fission of 252Cf

  16. Induction of a germline mutation at a hypervariable mouse minisatellite locus by 252Cf radiation

    International Nuclear Information System (INIS)

    Male C3H/HeN mice were exposed to 252Cf radiation and mated with unirradiated C57BL/6N females F1 mice were analyzed for germline mutation at the paternally derived C3H/HeN allele of a hypervariable minisatellite locus, Ms6hm. This locus exhibited a high frequency of length change mutation spontaneously, and the mutation frequency of the paternally derived C3H/He allele in F1 mice born to unirradiated males was 8.4%. Exposure of male mice to 252Cf radiation resulted in even higher frequency of germline mutation. The spermatid stage germ cells were most sensitive to neutrons, and the mutation frequencies of the paternal allele were elevated to 18%, 26% and 24% for 0.35, 0.7 and 1.02 Gy of 252Cf radiation, respectively. Spermatozoa and spermatogonia stages were less sensitive and the mutation frequencies for 1.02 Gy of 252Cf radiation were 16% and 19%, respectively. The 252Cf radiation consisted of 35% gamma-rays and 65% neutrons. Assuming that these two radiations act additively, RBE of 252Cf neutrons for the induction of minisatellite mutation was calculated to be 5.9 for spermatozoa stage irradiation, 2.6 for spermatid stage irradiation and 6.5 for spermatogonia irradiation. (author)

  17. Termocoagulación facetaria lumbar: Experiencia en 252 pacientes Thermocoagulation of lumbar facet joints: Experience in 252 patients

    Directory of Open Access Journals (Sweden)

    J. E. Martínez-Suárez

    2005-10-01

    Full Text Available Se presentan 252 pacientes con el diagnóstico de dolor lumbar facetario a los que se le realizó la técnica quirúrgica de termocoagulación percutánea de la faceta articular. Nuestro propósito principal fue aliviar el dolor en estos pacientes, evaluamos la eficacia de la técnica con un 74,7% de resultados quirúrgicos satisfactorios, así como la descripción de diferentes aspectos como: edad, sexo, causas y la topografía segmentaria del dolor.Two hundred fifty two patients with diagnosis of lumbar facet joint pain underwent the surgical technique of percutaneous thermocoagulation of the facet joint. Our major aim was to relief pain in those patients. We assess the effectiveness of the technique, with 74.7% of surgical success, and we also describe different aspects such as: age, sex, causes and segmentary pain topography.

  18. Antibiosis Contributes to Biological Control of Fire Blight by Pantoea agglomerans Strain Eh252 in Orchards.

    Science.gov (United States)

    Stockwell, V O; Johnson, K B; Sugar, D; Loper, J E

    2002-11-01

    ABSTRACT Fire blight, caused by Erwinia amylovora, is the most serious bacterial disease of pear and apple trees. Biological control with strains of Pantoea agglomerans (syn. Erwinia herbicola) may provide an effective disease management strategy for fire blight. Most strains of P. agglomerans evaluated for suppression of fire blight produce compounds that inhibit the growth of E. amylovora in culture. The role of these inhibitory compounds in fire blight suppression in orchard environments has not been studied. In seven field trials in Oregon, we compared the population dynamics and disease suppression with P. agglomerans Eh252, a strain that produces a single antibiotic, with its near-isogenic antibiotic-deficient derivative, strain 10:12. Water or suspensions of Eh252 or 10:12 (1 x 10(8) CFU/ml) were applied at 30 and 70% bloom to pear or apple trees. Aqueous suspensions of freeze-dried cells of E. amylovora (3 x 10(5) CFU/ml) were applied at full bloom. Additional trees were treated with streptomycin or oxytetracycline at 30 and 70% bloom and in some experiments, 1 day after application of the pathogen. Population sizes of Eh252 or 10:12 on pear blossoms were estimated by spreading dilutions of blossom washes on culture media. Average population sizes of Eh252 and 10:12 on blossoms ranged from 10(5) to 10(7) CFU, and in five of six trials, the relative area under the population curve of Eh252 was not significantly different than that of its derivative 10:12. Both Eh252 and 10:12 reduced the growth of the pathogen on blossoms compared with inoculated water-treated controls. Eh252 significantly decreased the incidence of fire blight in six of seven field trials compared with the incidence on water-treated trees, and 10:12 similarly reduced the incidence of fire blight in four of seven trials. In three of seven field trials, trees treated with Eh252 had a significantly lower incidence of fire blight compared with trees treated 3 with 10:12. Overall,3 Eh252 reduced

  19. Attributes and templates from active measurements with 252Cf

    International Nuclear Information System (INIS)

    Active neutron interrogation is useful for the detection of shielded HEU and could also be used for Pu. In an active technique, fissile material is stimulated by an external neutron source to produce fission with the emanation of neutrons and gamma rays. The time distribution of particles leaving the fissile material is measured with respect to the source emission in a variety of ways. A variety of accelerator and radioactive sources can be used. Active interrogation of nuclear weapons/components can be used in two ways: template matching or attribute estimation. Template matching compares radiation signatures with known reference signatures and for treaty applications has the problem of authentication of the reference signatures along with storage and retrieval of templates. Attribute estimation determines, for example, the fissile mass from various features of the radiation signatures and does not require storage of radiation signatures but does require calibration, which can be repeated as necessary. A nuclear materials identification system (NMIS) has been in use at the Oak Ridge Y-12 Plant for verification of weapons components being received and in storage by template matching and has been used with calibrations for attribute (fissile mass) estimation for HEU metal. NMIS employs a 252Cf source of low intensity (6 n/sec) such that the dose at 1 m is approximately twice that on a commercial airline at altitude. The use of such a source presents no significant safety concerns either for personnel or nuclear explosive safety, and has been approved for use at the Pantex Plant on fully assembled weapons systems

  20. Calculations of the cross sections for synthesis of new {293-296}118 isotopes in {249-252}Cf(48Ca,xn) reactions

    CERN Document Server

    Cap, T; Kowal, M; Wilczynski, J

    2013-01-01

    A project of using a target consisting of the mixture of (249-252)Cf isotopes to be bombarded with the 48Ca beam, aimed to synthesize new isotopes of the heaviest known element Z = 118, is under way at the FLNR in Dubna. In the present work excitation functions for all the reactions: 249Cf(48Ca,xn)(297-x)118, 250Cf(48Ca,xn)(298-x)118, 251Cf(48Ca,xn)(299-x)118 and 252Cf(48Ca,xn)(300-x)118 have been calculated in the framework of the fusion-by-diffusion model, assuming fission barriers, ground-state masses and shell effects of the superheavy nuclei predicted by Kowal et al. Energy dependence of the effective cross sections for the synthesis of selected new isotopes: (293)118, (294)118, (295)118 and (296)118 is predicted for the particular isotopic composition of the Cf target prepared for the Dubna experiment.

  1. Relative biological efficiency of powerful 252Cf mixed α-neutron radiation

    International Nuclear Information System (INIS)

    Comprehensive radiobiological studies of the relative biological and genetic efficacy (RBE and RGE) of powerful 252Cf radiation (the ANET-B unit) were conducted using research tools of various radiosensitivity (bacteria, Drosophila, Chinese hamster cells, murine thymocytes, human and murine bone marrow stem cells, human peripheral blood lymphocytes, Lewis lung carcinoma cells). It was shown in the tests of reproductive or interphase death and chromosome aberrations that the RBE and the RGE values of a sup(252)Cf new source varied within the same limits from 1.3 to 3.0 whereas in the tests of gene mutations the RGE of the source did not exceed the efficacy of 60Co γ-radiation and in some cases it was much lower. Thus the RBE of the new source in induced lethal and chromosome demages was 2-4 times lower than the efficacy of a low-activity sup(252)Cf source used now in radiotherapy

  2. Orientations of fragments emitted in binary cold fission of 252Cf

    International Nuclear Information System (INIS)

    The dependence of the driving potential on the orientation of fragments at scission is investigated for the case of cold fission of 252Cf. It is shown that in the case of cold fission the fragments exclusively emerge at scission in the pole-pole configuration. However, quantum fluctuations enable small deviations from this configuration during the tunnelling process. The mass yields of fission fragment pairs in the cold fission of 252Cf are computed for pole-pole and equator-equator orientations and are compared to the experimental data

  3. Atomic mass identification of CF-252 fission fragments using an NE-102 thin film detector

    International Nuclear Information System (INIS)

    The measurement of atomic number of low energy Cf-252 fission products using a three element thin film scintillation detector in conjunction with a residual energy solid state detector is described. Critical comparison of the separate spectra yielded by the three thin film elements is used to show both quantitative and qualitative consistency. Through the use of simple data handling techniques, increased resolution between peaks is easily obtained; the resultant spectrum for the distribution of both heavy and light fragments of Cf-252 is presented. The anticipated application of thin film scintillation techniques for event-by-event illucidation of decay schemes will also be discussed

  4. Safety analysis of doubly encapsulated 252Cf medical sources, Model TALC-PC

    International Nuclear Information System (INIS)

    This document describes the doubly encapsulated 252Cf neutron sources prepared for use in remote afterloading cancer brachytherapy. These neutron sources are classed as special form radioactive material and as such must meet certain Regulations prescribed by the U.S. Department of Transportation. This document describes the tests that have been performed and shows that this group of medical sources does meet the applicable DOT Regulations. The doubly encapsulated neutron sources are fabricated by the Savannah River Laboratory and are loaned by the U.S. Energy Research and Development Administration under contract agreement to medical organizations for evaluation of 252Cf in the treatment of cancer

  5. Water-extended polyester neutron shield for a 252Cf neutron source

    International Nuclear Information System (INIS)

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, 252Cf and shielding were modelled and the neutron spectra as well as the H*(10) were calculated in four sites. The calculation was extended to include a water shielding, the source in vacuum and in air. Besides neutron shielding characteristics, the Kerma in air due to gammas emitted by 252Cf and due to capture γ rays in the shielding were included. (authors)

  6. M-C simulation of 252Cf spontaneous fission n/γ TOF and TCC spectra

    International Nuclear Information System (INIS)

    Time correlation coincidence (TCC) is an effective method to measure characteristics of fission materials. In this paper, MCNP code is used to simulate n/γ time-of-flight spectra (TOF) of a 252Cf spontaneous fission source detected by a BC-501A liquid scintillator. The results are in good agreement with the measured spectra. Therefore, n/γ TCC spectra of the 252Cf source are simulated. The results indicate that the n/γ TCC spectra are composed of the n-n, γ-γ, n-γ and γ-n coincidence. (authors)

  7. Response of CR-39 plastic track detector to 239Pu and 252Cf sources

    International Nuclear Information System (INIS)

    CR-39 plastic track detectors have been irradiated with 239Pu and 252Cf sources separately at nuclear physics laboratory B.H.U., Varanasi to investigate track recording properties of detector material. All detectors etched in 6.25N NaOH solution at different temperatures for different hours. The bulk and track etch rates are calculated for both detectors (irradiated by 239Pu and 252Cf sources separately). The diameter and sensitivity along the trajectory of the track have been determined at different temperatures. (author)

  8. 47 CFR 51.809 - Availability of agreements to other telecommunications carriers under section 252(i) of the Act.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Availability of agreements to other telecommunications carriers under section 252(i) of the Act. 51.809 Section 51.809 Telecommunication FEDERAL... Implementation of Section 252 of the Act § 51.809 Availability of agreements to other telecommunications...

  9. 40 CFR 436.252 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Effluent limitations guidelines... technology currently available. 436.252 Section 436.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE...

  10. 24 CFR 207.252c - Premiums-mortgages insured pursuant to section 238(c) of the Act.

    Science.gov (United States)

    2010-04-01

    ... HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES MULTIFAMILY HOUSING MORTGAGE INSURANCE Contract Rights.... All of the provisions of §§ 207.252 and 207.252a governing mortgage insurance premiums shall apply...

  11. 48 CFR 252.226-7000 - Notice of historically black college or university and minority institution set-aside.

    Science.gov (United States)

    2010-10-01

    ... black college or university and minority institution set-aside. 252.226-7000 Section 252.226-7000... Notice of historically black college or university and minority institution set-aside. As prescribed in 226.370—9(a), use the following clause: Notice of Historically Black College or University...

  12. 48 CFR 252.229-7009 - Relief from customs duty and value added tax on fuel (passenger vehicles) (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... and value added tax on fuel (passenger vehicles) (United Kingdom). 252.229-7009 Section 252.229-7009... Relief from customs duty and value added tax on fuel (passenger vehicles) (United Kingdom). As prescribed in 229.402-70(i), use the following clause: Relief from Customs Duty and Value Added Tax on...

  13. Microarray analysis of DNA damage repair gene expression profiles in cervical cancer cells radioresistant to 252Cf neutron and X-rays

    Directory of Open Access Journals (Sweden)

    Yang Zhen-Zhou

    2010-02-01

    Full Text Available Abstract Background The aim of the study was to obtain stable radioresistant sub-lines from the human cervical cancer cell line HeLa by prolonged exposure to 252Cf neutron and X-rays. Radioresistance mechanisms were investigated in the resulting cells using microarray analysis of DNA damage repair genes. Methods HeLa cells were treated with fractionated 252Cf neutron and X-rays, with a cumulative dose of 75 Gy each, over 8 months, yielding the sub-lines HeLaNR and HeLaXR. Radioresistant characteristics were detected by clone formation assay, ultrastructural observations, cell doubling time, cell cycle distribution, and apoptosis assay. Gene expression patterns of the radioresistant sub-lines were studied through microarray analysis and verified by Western blotting and real-time PCR. Results The radioresistant sub-lines HeLaNR and HeLaXR were more radioresisitant to 252Cf neutron and X-rays than parental HeLa cells by detecting their radioresistant characteristics, respectively. Compared to HeLa cells, the expression of 24 genes was significantly altered by at least 2-fold in HeLaNR cells. Of these, 19 genes were up-regulated and 5 down-regulated. In HeLaXR cells, 41 genes were significantly altered by at least 2-fold; 38 genes were up-regulated and 3 down-regulated. Conclusions Chronic exposure of cells to ionizing radiation induces adaptive responses that enhance tolerance of ionizing radiation and allow investigations of cellular radioresistance mechanisms. The insights gained into the molecular mechanisms activated by these "radioresistance" genes will lead to new therapeutic targets for cervical cancer.

  14. Analysis of linear energy transfers and quality factors of charged particles produced by spontaneous fission neutrons from 252Cf and 244Pu in the human body

    International Nuclear Information System (INIS)

    Absorbed doses, linear energy transfers (LETs) and quality factors of secondary charged particles in organs and tissues, generated via the interactions of the spontaneous fission neutrons from. 252Cf and. 244Pu within the human body, were studied using the Particle and Heavy Ion Transport Code System (PHITS) coupled with the ICRP Reference Phantom. Both the absorbed doses and the quality factors in target organs generally decrease with increasing distance from the source organ. The analysis of LET distributions of secondary charged particles led to the identification of the relationship between LET spectra and target-source organ locations. A comparison between human body-averaged mean quality factors and fluence-averaged radiation weighting factors showed that the current numerical conventions for the radiation weighting factors of neutrons, updated in ICRP103, and the quality factors for internal exposure are valid. (authors)

  15. 48 CFR 252.225-7032 - Waiver of United Kingdom Levies-Evaluation of offers.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Waiver of United Kingdom... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.225-7032 Waiver of United Kingdom Levies—Evaluation of offers. As prescribed in 225.1101(8), use the following provision: Waiver of United...

  16. 48 CFR 252.225-7033 - Waiver of United Kingdom levies.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Waiver of United Kingdom... of Provisions And Clauses 252.225-7033 Waiver of United Kingdom levies. As prescribed in 225.1101(9), use the following clause: Waiver of United Kingdom Levies (APR 2003) (a) The U.S. Government...

  17. 48 CFR 252.232-7003 - Electronic submission of payment requests and receiving reports.

    Science.gov (United States)

    2010-10-01

    ... PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.232-7003 Electronic submission of payment... administering the contract for payment has determined, in writing, that electronic submission would be unduly... non-electronic payment requests using the method or methods specified in Section G of the contract....

  18. 46 CFR 252.22 - Substantiality and extent of foreign-flag competition.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Substantiality and extent of foreign-flag competition... WORLDWIDE SERVICES Operation § 252.22 Substantiality and extent of foreign-flag competition. (a) Type and tonnage groupings. Foreign-flag competition shall be determined, as of January 1 of the year...

  19. Remark on the prompt-fission-neutron spectrum of 252Cf

    International Nuclear Information System (INIS)

    Good resolution time-of-flight measurements show small structure in the prompt fission neutron spectrum of 252Cf that is identified with air-scattering effects. The observed high energy portion of the neutron spectrum is consistent with a Maxwellian distribution having a temperature of 1.42 MeV

  20. 48 CFR 252.242-7004 - Material management and accounting system.

    Science.gov (United States)

    2010-10-01

    ... CLAUSES Text of Provisions And Clauses 252.242-7004 Material management and accounting system. As prescribed in 242.7204, use the following caluse: Material Management and Accounting System (JUL 2009) (a) Definitions. As used in this clause— (1) Material management and accounting system (MMAS) means the...

  1. LARGE GAMMA ANISOTROPY OBSERVED IN THE CF-252 SPONTANEOUS-FISSION PROCESS

    NARCIS (Netherlands)

    VANDERPLOEG, H; BACELAR, JC; VANDENBERG, T; IACOB, VE; JONGMAN, [No Value; VANDERWOUDE, A

    1992-01-01

    The energy spectrum and the angular dependence relative to the fission direction of photons in the energy region between 2 and 40 MeV have been measured for the spontaneous fission of Cf-252. A large anisotropy was found in the energy region 8 to 12 MeV implying that photons in this region are emitt

  2. STUDY OF THE GAMMA EMISSION PROBABILITY ACCOMPANYING THE SPONTANEOUS FISSION OF CF-252

    NARCIS (Netherlands)

    VANDERPLOEG, H; LAURENS, CR; BACELAR, JCS; BUDA, A; GAARDHOJE, JJ; VANTHOF, G; KALANTARNAYESTANAKI, N; VANDERWOUDE, A; ZELAZNY, Z

    1994-01-01

    A study of the gamma emission accompanying the spontaneous fission process of Cf-252 has been performed. The photon emission probability between 3 and 70 MeV and its angular dependence with respect to the fission direction were measured. These measurements were performed as a function of the mass as

  3. Changes of mandibular incisor in Fgfr2 S252W mutant mice

    Directory of Open Access Journals (Sweden)

    Xia ZHOU

    2013-11-01

    Full Text Available Objective To compare the phenotypic differences of mandibular incisor between the wild-type mice and fibroblast growth factor receptor 2 (Fgfr2 gene S252W mutant mice, and explore the influence of gain-of-function mutation in Fgfr2 gene on mandibular incisors in mice. Methods The male EⅡa-Cre mice were mated with Fgfr2S252W-neo/+ females to obtain the Fgfr2 S252W mutant mice. On the 56th day after offspring's birth (P56, samples were taken for Micro-CT, HE staining and calcein double fluorescent labeling to observe the gross appearance, tissue morphology and mineral apposition rate of mandibular incisors, respectively. Results The newborn mutant mice showed short cranial deformity, which became more obvious on P56. Micro-CT showed a significant elongation and cross-bite deformity of mandibular incisors. HE staining showed that there were more ameloblasts and odontoblasts in the mutant mice, mostly with irregular appearance; epithelial diaphragm composed of inner and outer enamel epithelium shrank. Calcein double fluorescent labeling showed that the mineral apposition rate of dentin in mutant mice was significantly higher than that in controls. Conclusion Fgfr2 S252W mutation accelerates the growth of mandibular incisors in mice, resulting in the elongation and cross-bite deformity of mandibular incisors. DOI: 10.11855/j.issn.0577-7402.2013.10.005

  4. 48 CFR 252.229-7006 - Value added tax exclusion (United Kingdom).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Value added tax exclusion... CLAUSES Text of Provisions And Clauses 252.229-7006 Value added tax exclusion (United Kingdom). As prescribed in 229.402-70(f), use the following clause: Value Added Tax Exclusion (United Kingdom) (JUN...

  5. 48 CFR 252.229-7011 - Reporting of Foreign Taxes-U.S. Assistance Programs.

    Science.gov (United States)

    2010-10-01

    ... all value added taxes and customs duties imposed by the recipient country. This exemption is in... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Reporting of Foreign Taxes... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.229-7011 Reporting of Foreign...

  6. 48 CFR 252.227-7006 - License grant-running royalty.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false License grant-running... of Provisions And Clauses 252.227-7006 License grant—running royalty. As prescribed at 227.7009-4(a...—Running Royalty (AUG 1984) (a) The Contractor hereby grants to the Government, as represented by...

  7. 48 CFR 252.227-7007 - License term-running royalty.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false License term-running... of Provisions And Clauses 252.227-7007 License term—running royalty. As prescribed at 227.7009-4(b), insert the following clause in patent releases, license agreements, and assignments: License...

  8. 48 CFR 252.219-7003 - Small business subcontracting plan (DoD contracts).

    Science.gov (United States)

    2010-10-01

    ... AND CONTRACT CLAUSES Text of Provisions And Clauses 252.219-7003 Small business subcontracting plan...-9, Small Business Subcontracting Plan, clause of this contract. (a) Definitions. Historically black... Education to meet the requirements of 34 CFR 608.2. The term also means any nonprofit research...

  9. 48 CFR 252.229-7000 - Invoices exclusive of taxes or duties.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Invoices exclusive of... CLAUSES Text of Provisions And Clauses 252.229-7000 Invoices exclusive of taxes or duties. As prescribed in 229.402-1, use the following clause: Invoices Exclusive of Taxes or Duties (JUN 1997)...

  10. Combination of HPLC and 252-Cf plasma desorption mass spectrometry for identifying composition of ginseng tinctures.

    Science.gov (United States)

    Elkin, Y N; Makhankov, V V; Uvarova, N L; Bondarenko, P V; Zubarev, R A; Knysh, A N

    1993-03-01

    The 252-Cf plasma desorption mass spectrometry (252-Cf PDMS) determination or confirmation of the ginsenoside saponins has been proposed to investigate the composition of high performance liquid chromatography (HPLC) peaks of ginseng tinctures and galenic preparations. That ionization technique is well suitable for the analysis of natural mixtures of these saponins. The 252-Cf PD mass spectra of standard ginsenosides Rb1, Rb2, Rc, Re, Rg1, Rd, NG-R2, Z-R1 contain the peaks of two types of ions, namely, molecular adduct ions (MAI) and aglycone ions. By mass the latter may be referred to either protopanaxadiol or protopanaxatriol. The masses of MAI and aglycone ions are determined by the carbohydrate chains. The collected HPLC fractions of P ginseng tincture can be tested for content of ginsenosides. After studying two MAI peaks from the 252-Cf PD mass spectra of the basic ginsenosides, an example of distinction between two galenic preparations from different Panax has been shown. PMID:8352021

  11. 48 CFR 252.222-7003 - Permit from Italian Inspectorate of Labor.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Permit from Italian... CLAUSES Text of Provisions And Clauses 252.222-7003 Permit from Italian Inspectorate of Labor. As prescribed in 222.7201(b), use the following clause: Permit from Italian Inspectorate of Labor (JUN...

  12. 48 CFR 252.227-7039 - Patents-reporting of subject inventions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Patents-reporting of... CLAUSES Text of Provisions And Clauses 252.227-7039 Patents—reporting of subject inventions. As prescribed in 227.303(1), use the following clause: Patents—Reporting of Subject Inventions (APR 1990)...

  13. 48 CFR 252.227-7012 - Patent license and release contract.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Patent license and release... of Provisions And Clauses 252.227-7012 Patent license and release contract. As prescribed at 227.7012, insert the following clause in patent releases, license agreements, and assignments: (Contract...

  14. Calibration of a Manganese Bath Relative to 252Cf Nu-Bar

    Science.gov (United States)

    Gilliam, David M.; Yue, Andrew T.; Scott Dewey, M.

    2009-08-01

    A large manganese sulfate bath is employed at the National Institute of Standards and Technology (NIST) to calibrate isotopic neutron sources relative to the national standard neutron source NBS-I. In the past few years many low-emission Cf-252 neutron sources have been calibrated for testing of neutron detectors for the U.S. Department of Homeland Security (DHS). The low-emission DHS sources are about a factor of 100 lower in emission rate than NBS-I, so that background fluctuations become more significant in making accurate calibrations. To verify and improve the calibrations relative to NBS-I, a new calibration for sealed Cf-252 neutron sources has been made by measuring the fission rate of a bare Cf-252 deposit and inferring its neutron emission rate from Cf-252 nu-bar, the well-established neutron multiplicity of spontaneous fission in Cf-252. The fission rate of the bare deposit was measured by counting fission fragments in vacuum with a surface barrier detector behind an aperture and spacer, which provided a well-defined solid angle for detection. A thin polyimide film was placed just above the Cf deposit to prevent contamination of the detector by self-sputtering of the Cf material in vacuum. Tests with additional layers of polyimide were performed to observe any perturbation in the detection efficiency due to scattering or absorption of alpha particles or fission fragments in the polyimide film. The increase in the background count rate due to accumulation of Cf on the polyimide film was less than 0.02% of the fission fragment count rate from the sample, at the end of all runs. It is estimated that this increase in background would have been about 150 times higher without the polyimide film. The sealed Cf source NIST-DHSA was compared to the bare source by relative neutron counting in an assembly of polyethylene moderator and He-3 detectors. The calibration via Cf-252 nu-bar gave a result that was 1.7% higher than the previous calibration relative to NBS

  15. 利用示踪252Cf中子源的材料鉴别技术%Material Recognition by Using 252Cf Source

    Institute of Scientific and Technical Information of China (English)

    郝昕; L. Sajo-Bohus; 竺礼华; L. Stevanato; D. Fabris; M. Lunardon; S. Moretto; G. Nebbia; S. Pesente; G. Viesti

    2011-01-01

    Non-destructive assay of parcels using a tagged 252Cf source and time of flight technique was studied.The method of material recognition was achieved by measuring simultaneously the transmission of neutron and gamma ray to determine the average atomic number.The automatic tomography was realized with the movement of motors and autostart of the digital acquisition system.With the calibration of the detectors, the average atomic number for each pixel of the sample was determined which allows one to recognize material with this method.%本文叙述了利用252Cf裂变中子源结合飞行时间技术对包裹进行无损检测的可行性研究,通过联合测量中子和伽玛射线的吸收谱确定样品的平均原子序数,完成被测材料的鉴定.实验采用自发裂变的252Cf中子源作为白中子源和伽马射线源,用塑料闪烁探测器探测中子和伽马射线.通过LabVIEW程序控制步进电机运动并整合获取的实验数据,实现了待测样品断层扫描数据采集工作的自动化.在对闪烁探测器进行能量和时间刻度后,对几种典型材料组成的样品进行实验分析,采集数据重建其分布图像,确认了用这项技术对材料无损检测的可行性.

  16. Deoxyribonucleic acid initiation mutation dnaB252 is suppressed by elevated dnaC+ gene dosage.

    OpenAIRE

    Sclafani, R A; Wechsler, J A

    1981-01-01

    The Escherichia coli dnaB252 allele is the only dnaB mutation which confers a deoxyribonucleic acid initiation-defective phenotype on the cell. The presence of a multicopy hybrid plasmid containing the dnaC+ gene in a dnaB252 strain completely suppressed the temperature-sensitive phenotype. It is suggested that at high temperature the dnaB252 protein has a lowered affinity for dnaC protein, and that the formation of a dnaB-dnaC complex is mandatory for initiation.

  17. Review of RBE and OER values for Cf-neutrons

    International Nuclear Information System (INIS)

    Californium-252, an isotope emitting neutrons, gamma photons and alpha particles, is being investigated for its practical use in intracavitary and interstitial brachytherapy. A review of published RBE and OER values for californium neutrons as a function of dose rate for a variety of biological endpoints is given. (Auth.)

  18. Validation of IRDFF in 252Cf Standard and IRDF-2002 Reference Neutron Fields

    Science.gov (United States)

    Simakov, Stanislav; Capote, Roberto; Greenwood, Lawrence; Griffin, Patrick; Kahler, Albert; Pronyaev, Vladimir; Trkov, Andrej; Zolotarev, Konstantin

    2016-02-01

    The results of validation of the latest release of International Reactor Dosimetry and Fusion File, IRDFF-1.03, in the standard 252Cf(s.f.) and reference 235U(nth,f) neutron benchmark fields are presented. The spectrum-averaged cross sections were shown to confirm IRDFF-1.03 in the 252Cf standard spontaneous fission spectrum; that was not the case for the current recommended spectra for 235U(nth,f). IRDFF was also validated in the spectra of the research reactor facilities ISNF, Sigma-Sigma and YAYOI, which are available in the IRDF-2002 collection. The ISNF facility was re-simulated to remove unphysical oscillations in the spectrum. IRDFF-1.03 was shown to reproduce reasonably well the spectrum-averaged data measured in these fields except for the case of YAYOI.

  19. Ten-year cures of gynecologic tumors with Cf-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    In 1976, Cf-252 was a novel and clinically untested fast-neutron-emitting radioisotope that had been proposed for neutron brachytherapy (NT). About 20 primary tumors had been treated; recurrences had been used to estimate a clinical RBE. Clinical trials at the University of Kentucky treated advanced cervical tumors with intracavitary Cf-252 NT with whole-pelvis photon radiation (50-60 Gy). Local control and up to 10-year survivals were achieved without significant side effects or secondary neoplasms (eg, hematologic malignancies). Treatments were done on an outpatient basis, were much shorter, were better tolerated by medically ill, bleeding, infected, or morbidly obese patients, and produced quicker tumor response with greatly reduced costs. Long-term outcome will be reviewed

  20. Frequency spectrum analysis of 252Cf neutron source based on LabVIEW

    International Nuclear Information System (INIS)

    The frequency spectrum analysis of 252Cf Neutron source is an extremely important method in nuclear stochastic signal processing. Focused on the special '0' and '1' structure of neutron pulse series, this paper proposes a fast-correlation algorithm to improve the computational rate of the spectrum analysis system. And the multi-core processor technology is employed as well as multi-threaded programming techniques of LabVIEW to construct frequency spectrum analysis system of 252Cf neutron source based on LabVIEW. It not only obtains the auto-correlation and cross correlation results, but also auto-power spectrum,cross-power spectrum and ratio of spectral density. The results show that: analysis tools based on LabVIEW improve the fast auto-correlation and cross correlation code operating efficiency about by 25% to 35%, also verify the feasibility of using LabVIEW for spectrum analysis. (authors)

  1. Performance evaluation of high-pressure MWPC with individual line readout under Cf-252 neutron irradiation

    International Nuclear Information System (INIS)

    A multiwire proportional chamber (MWPC) neutron detector system was developed for the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. Its basic performance was evaluated by an irradiation experiment using a Cf-252 neutron source. A short response time and high spatial resolution can be obtained using an individual line readout method. The detector system exhibited a one-dimensional uniformity of response of 4.8% and 3.8% in the x- and y-directions, respectively. The uniformity of all pixels in the two-dimensional image was 7.9%. The average intrinsic spatial resolution was 1.55 mm full width at half maximum in the sensitive region calculated by taking into account the track lengths of secondary particles. The signal intensity of the system remained constant during the operation for 500 min under Cf-252 neutron irradiation.

  2. Shielding of radiation fields generated by 252Cf in a concrete maze. Part 1: Experiment

    International Nuclear Information System (INIS)

    A concrete room with a single-legged maze was constructed in order to simulate a medical accelerator room. Gamma and neutron measurements were performed along the maze with (a) a 252Cf source and (b) a tungsten-moderated 252Cf source placed inside the room. The measurements were repeated after placing an inner borated polyethylene door of varying thickness (2.54--10.16 cm) at 2 different locations. Measurements were also performed after lining the inside of the maze with different neutron moderating materials. The following results are reported: (1) the variation and contributions of individual components of the radiation fields as a function of distance along the maze, (2) the attenuation of neutron dose equivalent and reduction of capture gamma rays as a function of borated polyethylene (BPE) inner door thickness and location of the inner door; and (3) the effect of lining the maze corner with different neutron moderating materials

  3. Validation of IRDFF in 252Cf Standard and IRDF-2002 Reference Neutron Fields

    Directory of Open Access Journals (Sweden)

    Simakov Stanislav

    2016-01-01

    Full Text Available The results of validation of the latest release of International Reactor Dosimetry and Fusion File, IRDFF-1.03, in the standard 252Cf(s.f. and reference 235U(nth,f neutron benchmark fields are presented. The spectrum-averaged cross sections were shown to confirm IRDFF-1.03 in the 252Cf standard spontaneous fission spectrum; that was not the case for the current recommended spectra for 235U(nth,f. IRDFF was also validated in the spectra of the research reactor facilities ISNF, Sigma-Sigma and YAYOI, which are available in the IRDF-2002 collection. The ISNF facility was re-simulated to remove unphysical oscillations in the spectrum. IRDFF-1.03 was shown to reproduce reasonably well the spectrum-averaged data measured in these fields except for the case of YAYOI.

  4. Microbial response to the MC252 Oil and Corexit 9500 in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Romy eChakraborty

    2012-10-01

    Full Text Available The Deepwater Horizon spill released over 4.1 million barrels of crude oil into the Gulf of Mexico. In an effort to mitigate large oil slicks, the dispersant Corexit 9500 was sprayed onto surface slicks and injected directly at the wellhead at water depth of 1,500 meters. Several research groups were involved in investigating the fate of the MC-252 oil using newly advanced molecular tools to elucidate microbial interactions with oil, gases and dispersant. Presented here is a comprehensive overview of the ecogenomics of microbial degradation of MC-252 oil and gases in the water column and shorelines and some insight into the fate of the dispersant Corexit 9500 that was added to aid in oil dispersion process. We also present data that show the dispersant was not toxic to the indigenous microbes at concentrations added, and several bacterial species were able to degrade the various components of Corexit 9500.

  5. Cf-252 based neutron radiography using real-time image processing system

    International Nuclear Information System (INIS)

    For compact Cf-252 based neutron radiography, a real-time image processing system by particle counting technique has been developed. The electronic imaging system consists of a supersensitive imaging camera, a real-time corrector, a real-time binary converter, a real-time calculator for centroid, a display monitor and a computer. Three types of accumulated NR image; ordinary, binary and centroid images, can be observed during a measurement. Accumulated NR images were taken by the centroid mode, the binary mode and ordinary mode using of Cf-252 neutron source and those images were compared. The centroid mode presented the sharpest image and its statistical characteristics followed the Poisson distribution, while the ordinary mode showed the smoothest image as the averaging effect by particle bright spots with distributed brightness was most dominant. (author)

  6. Oil in the Gulf of Mexico after the capping of the BP/Deepwater Horizon Mississippi Canyon (MC-252) well.

    Science.gov (United States)

    Kolian, Steve R; Porter, Scott A; Sammarco, Paul W; Birkholz, Detlef; Cake, Edwin W; Subra, Wilma A

    2015-08-01

    Evidence of fresh oil from the BP/Deepwater Horizon Mississippi Canyon-252 (MC-252) well was found in the northern Gulf of Mexico up to 1 year and 10 months after it was capped on 15 July 2010. Offshore and coastal samples collected after capping displayed ratios of biomarkers matching those of MC-252 crude oil. Pre- and post-capping samples were compared. Little weathering had occurred, based on the abundance of low-molecular-weight (LMW) n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in the post-capping samples. The occurrence of fresh oil in offshore waters and coastal areas suggest that the MC-252 well continued to leak hydrocarbons into the Gulf of Mexico at least until 22 May 2012, the end of this study period. PMID:25874429

  7. State Waste Discharge Permit application for industrial discharge to land: 200 East Area W-252 streams

    International Nuclear Information System (INIS)

    This document constitutes the WAC 173-216 State Waste Discharge Permit application for six W-252 liquid effluent streams at the Hanford Site. Appendices B through H correspond to Section B through H in the permit application form. Within each appendix, sections correspond directly to the respective questions on the application form. The appendices include: Product or service information; Plant operational characteristics; Water consumption and waterloss; Wastewater information; Stormwater; Other information; and Site assessment

  8. Structure of spontaneous fission spectrum of 252Cf and its impact on neutron albedo experiments' simulation

    International Nuclear Information System (INIS)

    Aimed at the problem of the energy spectrum of spontaneous fission source, which was used in neutron albedo experiments, we selected two sets of 252Cf fission spectra, which were fitted by formulae and were universally accepted. And they were applied in neutron albedo experiments independently. Neutron fluence and fission rate on each detecting point were compared and analyzed. The results show that Watt spectrum agrees the experiment data better than that of Maxwell spectrum. (authors)

  9. Advanced conceptual design report. Phase II. Liquid effluent treatment and disposal Project W-252

    International Nuclear Information System (INIS)

    This Advanced Conceptual Design Report (ACDR) provides a documented review and analysis of the Conceptual Design Report (CDR), WHC-SD-W252-CDR-001, June 30, 1993. The ACDR provides further design evaluation of the major design approaches and uncertainties identified in the original CDR. The ACDR will provide a firmer basis for the both the design approach and the associated planning for the performance of the Definitive Design phase of the project

  10. Neutron radiography research using 252Cf at General Dynamics' Convair Aerospace Division

    International Nuclear Information System (INIS)

    Neutron radiography research using 10 milligrams of 252Cf consisting of 4 sources in a water-moderated tank facility is described. Conventional direct-exposure techniques were employed with thermal neutrons from a 6-in. dia beam port. Typical examples with components representative of aerospace products are presented. Neutron radiography is compared with x-ray radiography for the cited examples, which include pyrotechnics and polyurethane insulation. (U.S.)

  11. Functional design criteria for Project W-252, Phase II Liquid Effluent Treatment and Disposal: Revision 1

    International Nuclear Information System (INIS)

    This document provides the functional design criteria required for the Phase 2 Liquid Effluent Treatment and Disposal Project, Project W-252. Project W-252 shall provide new facilities and existing facility modifications required to implement Best Available Technology/All Known, Available, and Reasonable Methods of Prevention, Control, and Treatment (BAT/AKART) for the 200 East Phase II Liquid Effluent Streams. The project will also provide a 200 East Area Phase II Effluent Collection System (PTECS) for connection to a disposal system for relevant effluent streams to which BAT/AKART has been applied. Liquid wastestreams generated in the 200 East Area are currently discharged to the soil column. Included in these wastestreams are cooling water, steam condensate, raw water, and sanitary wastewaters. It is the policy of the DOE that the use of soil columns to treat and retain radionuclides and nonradioactive contaminants be discontinued at the earliest practical time in favor of wastewater treatment and waste minimization. In 1989, the DOE entered into an interagency agreement with Ecology and EPA. This agreement is referred to as the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). Project W-252 is one of the projects required to achieve the milestones set forth in the Tri-Party Agreement. One of the milestones requires BAT/AKART implementation for Phase II streams by October 1997. This Functional Design Criteria (FDC) document provides the technical baseline required to initiate Project W-252 to meet the Tri-Party Agreement milestone for the application of BAT/AKART to the Phase II effluents

  12. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    International Nuclear Information System (INIS)

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for 252Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  13. Interfacing Of PIC 18F252 Microcontroller with Real Time Clock via I2C Protocol

    Directory of Open Access Journals (Sweden)

    Arnab G. Samanta

    2014-09-01

    Full Text Available This paper describes a microcontroller based digital clock which can be used in real time systems. The system is constructed using PIC18F252 (microcontroller, DS1307 (real time clock IC and its software program is written with C programming language. A 3v battery backup is provided to real time clock IC. Communication between PIC microcontroller and DS1307 takes place through I²C Bus protocol.

  14. State Waste Discharge Permit application for industrial discharge to land: 200 East Area W-252 streams

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    This document constitutes the WAC 173-216 State Waste Discharge Permit application for six W-252 liquid effluent streams at the Hanford Site. Appendices B through H correspond to Section B through H in the permit application form. Within each appendix, sections correspond directly to the respective questions on the application form. The appendices include: Product or service information; Plant operational characteristics; Water consumption and waterloss; Wastewater information; Stormwater; Other information; and Site assessment.

  15. 252Cf-based borehole logging system for in-situ assaying of uranium ore

    International Nuclear Information System (INIS)

    A 252Cf based borehole logging system for in-situ assaying of uranium ore has been designed and constructed, and preliminary tests of system operation have been performed. The system employs a delayed neutron activation analysis (DNAA) technique for which the downhole feasibility was demonstrated by Kerr--McGee. DNAA measures uranium directly, thereby circumventing the disequilibrium problems which are inherent to natural gamma ray logging. An improved DNAA technique has been implemented which utilizes a smaller 252Cf source and is more sensitive than the Kerr--McGee system. In particular, the size of the 252Cf source has been reduced by more than a factor of 10 with respect to the source employed by Kerr--McGee. Shielding for the 252Cf source has been designed for ease of operation while meeting occupational radiological safety requirements. The present system is vehicle mounted and includes the downhole sonde, logging winch with 1,000 meters of 4HO cable, data handling electronics, data recording and display equipment, and source shielding. The design of the system includes the following features: logging speeds from stationary to 8 meters/min with the capacity for determining 0.01% U3O8 concentration at 1.5 meters/min; uranium concentration readout independent of source intensity; auxiliary neutron measurement for accurate correlation of DNAA signal to actual U3O8 present; natural gamma ray detector for gauging disequilibrium; and short normal resistivity for lithology. The present system is a fully operational prototype. An extensive field calibration and evaluation program will begin shortly to uncover design problems and to allow simplification of the system for production logging. Commercially available units will reflect the operational experience gained from the testing program

  16. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    OpenAIRE

    Elango, Vijaikrishnah; Urbano, Marilany; Lemelle, Kendall R.; Pardue, John H.

    2014-01-01

    Unique oil:sand aggregates, termed surface residue balls (SRBs), were formed on coastal headland beaches along the northern Gulf of Mexico as emulsified MC252 crude oil mixed with sand following the Deepwater Horizon spill event. The objective of this study is to assess the biodegradation potential of crude oil components in these aggregates using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 19-month period on the supratid...

  17. Advanced conceptual design report. Phase II. Liquid effluent treatment and disposal Project W-252

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-31

    This Advanced Conceptual Design Report (ACDR) provides a documented review and analysis of the Conceptual Design Report (CDR), WHC-SD-W252-CDR-001, June 30, 1993. The ACDR provides further design evaluation of the major design approaches and uncertainties identified in the original CDR. The ACDR will provide a firmer basis for the both the design approach and the associated planning for the performance of the Definitive Design phase of the project.

  18. Burnout and gate rupture of power MOS transistors with fission fragments of 252Cf

    International Nuclear Information System (INIS)

    A study to determine the single event burnout (SEB) and single event gate rupture (SEGR) sensitivities of power MOSFET devices is carried out by exposure to fission fragments from 252Cf source. The test method, test results, a description of observed burnout current waveforms and a discussion of a possible failure mechanism are presented. The test results include the observed dependence upon applied drain or gate to source bias and effect of external capacitors and limited resistors

  19. Experiment research on single event burnout of power MOSFET devices with 252Cf source

    International Nuclear Information System (INIS)

    The method in simulation of radiation effect test by 252Cf source was introduced, and the single event burnout experiment was carried out. The research result indicates that power MOSFET devices should be operated at the lowest voltage range un- der the radiation environment in the space, and adding a resister to confine the current in the circuit is an effective reinforce to avoid single event burnout. (authors)

  20. A 2.52-mW continuous-time ΣΔ modulator with 72 dB dynamic range for FM radio

    International Nuclear Information System (INIS)

    A continuous-time ΣΔ modulator with a third-order loop filter and a 3-bit quantizer is realized. The modulator is robust to the excess loop delay, clock jitter, and RC product variations. When designing the integrator, an op-amp with novel GBW extension structure, improving the linearity of the loop filter, is adopted. The prototype chip is designed in a 130 nm CMOS technology, targeting FM radio applications. The experimental results show that the prototype modulator achieves a 72 dB dynamic range and a 70.7 dB signal to noise and distortion ratio over a 500 kHz bandwidth with a 26 MHz clock, consuming 2.52 mW power from a 1.2 V supply. (semiconductor integrated circuits)

  1. 252Cf spectrum-averaged cross section for the 63Cu(n, p)63Ni reaction

    Science.gov (United States)

    Imamura, M.; Shibata, T.; Shibata, S.; Ohkubo, T.; Satoh, S.; Nogawa, N.

    1999-01-01

    The 63Ni produced by the 63Cu(n, p)63Ni reaction provides a unique measure to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bomb. In the similarity of the fission neutron spectrum of 252Cf to that of 235U, we have measured activation cross sections of the 63Cu(n, p)63Ni reaction averaged for the 252Cf fission spectrum.

  2. A new spontaneous fission mode for 252Cf: Hyperdeformation, cluster radioactivity, new levels

    International Nuclear Information System (INIS)

    Direct measurements of yields and neutron multiplicities were made for Sr-Nd, Zr-Ce, Mo-Ba, Ru-Xe, and Pd-Te from γ-ray coincidence studies in spontaneous fission of 252Cf. Strong enhancement of the 7-10 ν emission channels is seen in the Mo-Ba data. Unfolding the Mo-Ba data revealed a new fission mode associated with the enhanced ν yields with much lower total kinetic energy going by 108Mo-144Ba, 107Mo- 145Ba, and/or 106Mo-146Ba. Analysis indicates one or more of 144,145,146Ba are hyperdeformed with 3:1 axis ratio. Theoretical calculations predict a third minimum in the PES for 252Cf with β2 ∼ 0.9 and β3 ∼ 0.7. Zero neutron emission channels, a new form of cluster radioactivity, are seen in 8 and 7 correlated pairs in SF of 252Cf and 242Pu, respectively, with the odd-odd zero neutron channel yields strongly enhanced as predicted for cluster radioactivity. New level structures and isotopes include new octupole deformations, identical bands and other structures

  3. Fission-Neutron Spectra of U235, Pu239 And Cf252

    International Nuclear Information System (INIS)

    Measurements of the fission neutron spectra from the neutron-induced fission of U235 and Pu239, and the spontaneous fission of Cf252, have been made. The spectra were measured with a time-of-flight technique using a plastic scintillator as the fission-neutron detector. The low energy part of the Cf252 fission-neutron spectrum (below 0.3 MeV) was also measured with a Li6 -glass detector replacing the plastic scintillator. The fissile materials were mounted in xenon-gas scintillation cham-bers. The primary neutrons were produced by a 2.5-MeV Van de Graaff accelerator with top terminal pulsing. The resolving time of the time-of-flight equipment was better than 3 ns. Results fitted to Maxwellian distributions, √Ee-E/T, are presented for neutron-induced fissions of U235 at 40 keV and 1.5 MeV of incident neutron energy and for Pu239 at 40 keV. Results are also given for the fission-neutron energy spectrum of Cf252. (author)

  4. On the 252Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    Science.gov (United States)

    Ghassoun, J.; Merzouki, A.; El Morabiti, A.; Jehouani, A.

    2007-10-01

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by 252Cf fission and also the primary gamma rays emitted directly by the 252Cf source at the exit face of a compact system designed for the BNCT. The system consists of a 252Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system.

  5. On the {sup 252}Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Merzouki, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco); Remote Sensing and Geomatics of the Environnement Laboratory, Ottawa-Carleton Geoscience Centre, Marion Hall-140Louis Pasteur Ottawa, ON, KIN 6N5 (Canada); El Morabiti, A.; Jehouani, A. [LPTN, Departement de Physique, Faculte des Sciences Semlalia, BP 2390, 40000 Marrakech (Morocco)

    2007-10-15

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by {sup 252}Cf fission and also the primary gamma rays emitted directly by the {sup 252}Cf source at the exit face of a compact system designed for the BNCT. The system consists of a {sup 252}Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system.

  6. On the 252Cf primary and secondary gamma rays and epithermal neutron flux for BNCT

    International Nuclear Information System (INIS)

    Monte Carlo simulation has been used to calculate the different components of neutrons and secondary gamma rays originated by 252Cf fission and also the primary gamma rays emitted directly by the 252Cf source at the exit face of a compact system designed for the BNCT. The system consists of a 252Cf source and a moderator/reflector/filter assembly. To study the material properties and configuration possibilities, the MCNP code has been used. The moderator/reflector/filter arrangement is optimised to moderate neutrons to epithermal energy and, as far as possible, to get rid of fast and thermal neutrons and photons from the therapeutic beam. To reduce the total gamma contamination and to have a sufficiently high epithermal neutron flux we have used different photon filters of different thickness. Our analysis showed that the use of an appropriate filter leads to a gamma ray flux reduction without affecting the epithermal neutron beam quality at the exit face of the system

  7. Test of the Bonner Sphere Spectrometer Response Matrix in the 252Cf Neutron Field

    International Nuclear Information System (INIS)

    Full text: Since its development in 1960, a Bonner sphere spectrometer (BSS) has been the only instrument, which enables the spectral neutron fluence to be measured in a wide range of energies from thermal up to 20 MeV. Its resolution is poor but sufficient for dosimetric specification of neutron fields at workplaces. Experimentally determined BSS count rates depends mainly on the accuracy of the response matrix characterising certain type of BSS. At presemt the BSS response matrices are calculate by neutron transport Monte Carlo codes which allow detailed description of the BSS setup. The best verification of calculated response matrix is a calibration of the BSS in fields of monoenergetic neutrons. As so as these fields are not simply achievable a simple method how to test quality of BSS response matrix in the neutron field of 252Cf source is described. Applying distance variation method we get count rates of the BSS in the 252Cf field from which contributions of scattered neutrons and influence of finite detector and source dimensions were removed. These count rates are compared with the integrals of pure 252Cf spectrum and responses for individual spheres of the BSS. Disagreement indicates for which sphere the response is not properly determined. (author)

  8. Averaged U238 fission cross section measurement in Cf-252 neutron spectrum

    International Nuclear Information System (INIS)

    With regard to the standardization of Cf-252 neutron spectrum, the averaged U-238 fission cross section was measured over the Cf-252 neutron spectrum using foil activation technique. The gamma spectra of the fission products were obtained on a pure germanium detector at different decay times in order to identify the gamma rays of short, medium and long half-life radioisotopes. Analyzing the gamma spectra of the irradiated uranium foils several distinct photopeaks of several fission products were identified. The pure activity of Te-132 was determined from the net area under 228.2 kev photopeak after correcting it for neighbouring photopeaks of Np-239 and Pa-234. The averaged U238 fission cross section was calculated from the corrected counts of Te-132 photopeak to be 329±10 mb. The main sources of errors in the measurements are mainly due to inaccuracy of location of foils, neutron flux, counting statistics, weight of foils, impurity of foils and interference from neighbouring photopeaks. The contribution of fission neutrons from spontaneous fission of Cm-248, daughter of Cf-252, to the total flux density was estimated at 0.13%. (orig.)

  9. High energy {gamma} emission in the spontaneous fission of {sup 252}Cf; Emission {gamma} de grande energie dans la fission spontanee de {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Thiesen, Ch. [Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Belier, G.; Meot, M.V. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Inst.de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-06-01

    The prompt {gamma} emission in the spontaneous fission of {sup 252}Cf is characterized by an energy spectrum which extends up to 20 MeV. It was established that the spectrum presents in the neighbourhood of symmetric fission an intensity bump in the 3-8 MeV {gamma} energy interval. The origin of this phenomenon is still not well understood, so that it was found interesting to carry out new measurements. The spectrum of the {gamma} rays emitted in spontaneous fission of {sup 252}Cf has been measurement in the EUROGAM II multidetector using photovoltaic cells to detect fragments. The aim of the experiment was to investigate the {gamma} yield enhancement which appears for mass fragment ratio near 132/120. This enhancement was found to be composed of two peaks located at 4 MeV and 5.5 MeV respectively. The results obtained confirm the intensity bound in the 3-8 MeV region but this augmentation reaches the maximum when the heavy fragment is near the mass 132. Beyond mass 140 the phenomenon diminish and the {gamma} spectrum regains the behaviour expected for a statistic emission. The additional structure at 5.5 MeV does not vary with excitation energy while the excitation function of the 4 MeV structure is more structured and presents a maximum when the excitation energy is near 8 MeV. It is likely that all or part of this observed phenomenon is due to a particular excitation mode of this isotope associated for instance with a low energy dipole resonance. A theoretical study of this collective effect is under way 3 refs.

  10. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

  11. Sputter target

    Science.gov (United States)

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  12. Dosimetric analysis of BNCT - Boron Neutron Capture Therapy - coupled to 252Cf brachytherapy

    International Nuclear Information System (INIS)

    The incidence of brain tumors is increasing in world population; however, the treatments employed in this type of tumor have a high rate of failure and in some cases have been considered palliative, depending on histology and staging of tumor. Its necessary to achieve the control tumor dose without the spread irradiation cause damage in the brain, affecting patient neurological function. Stereotactic radiosurgery is a technique that achieves this; nevertheless, other techniques that can be used on the brain tumor control must be developed, in order to guarantee lower dose on health surroundings tissues other techniques must be developing. The 252Cf brachytherapy applied to brain tumors has already been suggested, showing promising results in comparison to photon source, since the active source is placed into the tumor, providing greater dose deposition, while more distant regions are spared. BNCT - Boron Neutron Capture Therapy - is another technique that is in developing to brain tumors control, showing theoretical superiority on the rules of conventional treatments, due to a selective irradiation of neoplasics cells, after the patient receives a borate compound infusion and be subjected to a epithermal neutrons beam. This work presents dosimetric studies of the coupling techniques: BNCT with 252Cf brachytherapy, conducted through computer simulation in MCNP5 code, using a precise and well discretized voxel model of human head, which was incorporated a representative Glioblastoma Multiform tumor. The dosimetric results from MCNP5 code were exported to SISCODES program, which generated isodose curves representing absorbed dose rate in the brain. Isodose curves, neutron fluency, and dose components from BNCT and 252Cf brachytherapy are presented in this paper. (author)

  13. Importance of the neutrons kerma coefficient in the planning of Brachytherapy treatments with Cf-252 sources

    International Nuclear Information System (INIS)

    The Cf-252 is a fast neutrons emitting radioisotope by spontaneous fission that can be used as sealed source in medicine applications, industry and research. Commercially its offer sources of different sizes, compact and with a fast neutrons emission of the order of 106 n/s-μg and an energy spectra that presents respectively maxim and average energy in 2.1 MeV and 0.7 MeV. In medicine new applications are being developed for the treatment of patient with hypoxic and voluminous tumors, where the therapy with photons has not given positive results, as well as for the protocols of therapy treatment by boron neutron capture, where very small sources of Cf-252 will be used with the interstitial brachytherapy technique of high and low dose rate. In this work an analysis of how the small differences that exist in the elementary composition of 4 wicked tumors, 4 ICRU healthy tissues and 3 substitute materials of ICRU tissue used in dosimetry are presented, its generate changes in the neutrons kerma coefficient in function of the energy and consequently in the absorbed dose in the interval of 11 eV to 29 MeV. These differences can produce maximum variations of the neutron kerma coefficients ratio for En > 1 keV of the one: 15% tumor/ICRU guest healthy tissue, 12% ICRU tumor/muscle, 12% ICRU healthy tissues ICRU/ICRU muscle, 22% substitutes tissue/tumor and 22% ICRU substitutes tissue/muscle. Also, it was found that the average value of the neutrons kerma coefficient for the 4 wicked tumors is from 6% to 7% smaller that the average value for the soft tissue in the interval energy of interest for therapy with fast neutrons with En > 1 MeV. These results have a special importance during the planning process of brachytherapy treatments with sources of 252Cf, to optimize and to individualize the patients treatments. (Author)

  14. Possibilities of detection of valuable metals in manganese nodules utilizing of Cf 252 neutron source

    International Nuclear Information System (INIS)

    For a long-term maintainance of the supply of non-iron metals the exploration of marine ore deposits becomes more and more important. In the special case of the so-called manganese nodules deposited on the deep ocean floor, a rather continuous method is required, by which the metals manganese, copper, nickel, cobalt and iron, or some of them, could be determined in situ, for short with an analytical error of about 20 to 50% analysis times. The possibility of performing such analyses by aid of the capture gamma radiation induced by a Cf 252 neutron source - which appeared to be promising - has been tested experimentally, simultaneous of referring to the maximum analizing time of 10 min demanded by application. For this purpose genuine manganese nodules have been irradiated at a 1 mg Cf 252 source. Decay gamma radiation as well as capture gamma radiation have been measured individually. The spectra from these measurements allowed to determine the statistical error of characteristic lines of the individual metal and thus their detectability. The measurement of decay gamma radiation (up to 2 MeV) showed that, within the short analyzing time, only manganese is detectable with a relative error of 1% referring to 10 g sample material. The measurement of capture gamma radiation (up to 10 MeV) verified the detection of the five metals of interest (Mn, Fe, Cu, Ni). An increase of the sample quantity up to 10 kg, corresponding to realistic prospection conditions, yielded within 10 min following relative errors: Mn 3 to 4%, Fe 7 to 8%, Cu 20 to 25%, Co 50% and Ni 12 to 20%. An experimental arrangement with the Cf 252 source and the sample situated in a water tank proved the practicability of such measurements even in presence of large quantities of water. (orig.)

  15. Observed branching ratios of alpha to fission fragments of Cf252 using CR-39

    International Nuclear Information System (INIS)

    There has been a rapid growth in the application of SSNTD to the study of nuclear phenomena in the recent past. The considerable ease introduced in recording the signature of heavy ions in the presence of alpha particles has made them particularly suitable for the study of spontaneous fission of transuranic elements. It is the object of the present study to explore the response of CR-39 for the determination of the branching ratios of alpha to fission fragments of Cf252 at the end of almost one and four half-life periods for alpha decay. The results more or less confirm the expected values

  16. Observation of Light Shape Isomers in the Multi-Body Decay of 252Cf (sf)

    Science.gov (United States)

    Pyatkov, Yu. V.; Kamanin, D. V.; Alexandrov, A. A.; Alexandrova, I. A.; Kondratyev, N. A.; Kuznetsova, E. A.; Strekalovsky, A. O.; Strekalovsky, O. V.; Zhuchko, V. E.; Mkaza, N.; Malaza, V.

    2015-11-01

    We observe an essential mass deficit in the total mass of the fission fragments detected in coincidence with Ti ions knocked out from the foil placed near a 252Cf source. This could be expected if the scattered fragment looks like a di-nuclear system breaking up due to inelastic scattering on the Ti nucleus. The mean flight time between the Cf source and the foil does not exceed 0.1 ns. This can be regarded as a lower limit for the life-time of the di-nuclear system (shape-isomer).

  17. Measurement of reflect neutron for 252Cf in cement cylinder by method of 235U fission

    International Nuclear Information System (INIS)

    The experiment theory of Research of neutron reflected coefficient for 252Cf in cement reflector was introduced. The fission rate of 235U with reflector, without reflector and with background was measured. The neutron reflected coefficient with cement reflector was concluded from fission rate and the reflected coefficient for different neutron source in the same experiment model was compared. The relation of reflected coefficient with angle was analyzed. The technology of solid track was researched and the best etch condition was explored. The trend of discharge count with coders thickness and etch thickness was gained. Efficiency for spark auto counters was measured and the technology of solid track was developed. (authors)

  18. Response measurement of three scintillation detector to instantaneous rays from 252Cf fission

    International Nuclear Information System (INIS)

    By TOF, the responses of LaCl3 (Ce), BC400, ST401 scintillation detectors to instantaneous rays from 252Cf fission are measured. The output waveform parameters, timing precision, counts above different neutron energy thresholds are obtained. The response of LaCl3 (Ce) detector shielded by HDPE is measured. The γ-ray timing precision of BC400 detector can reach 1.3 ns, and ST401 can reach 1.5 ns. Matching fast PMT, LaCl3 (Ce) detector could measure γ-ray pulse time sequence effectively. (authors)

  19. Analysis of molasses samples from various sugar industries in Maharashtra using 252Cf neutron source

    International Nuclear Information System (INIS)

    The molasses samples from various sugar industries in Maharashtra State have been analysed for their physico-chemical characteristics as well as elemental contents. The elements sodium, potassium, chlorine and manganese were determined using 252Cf neutron source by instrumental neutron activation analysis (INAA). Other parameters such as ash, moisture, total dissolved solids, pH as well as element Ca were estimated by usual conventional chemical methods. The percentage of various parameters varies from industry to industry and the concentration of elements is found in the order K > Ca > Cl > Na> Mn. (author). 3 refs., 2 tabs

  20. Molecular vibrational states in the binary cold fission of $^{252}$Cf

    OpenAIRE

    Misicu, S.; Sandulescu, A.; Greiner, W.

    1998-01-01

    We predict a molecular vibrational state in the cold binary fission of $^{252}$Cf using a simple decay cluster model. The Hamiltonian of two even-even fragments in the pole-pole configuration is built in the same fashion as that for the dinuclear molecule formed in heavy-ions collisions. The interaction between the two fragments is described by the double-folding M3Y potential. The spectrum of the butterfly vibrations is derived and its dependence on fragments deformation and mass-assymetry i...

  1. Rotational properties of $^{252, 253, 254}$No. Influence of pairing correlations

    OpenAIRE

    Duguet, T.; Bonche, P.; Heenen, P. -H.

    2000-01-01

    Rotational bands of $^{252, 253, 254}$No and the fission barriers of $^{254}$No at spin 0$\\hbar$ and 20$\\hbar$ are calculated with the Hartree-Fock-Bogolyubov theory and the Lipkin-Nogami approximate particle number projection. The SLy4 Skyrme force is used in the particle-hole channel. A zero-range force with and without density-dependence is used in the particle-particle channel. The experimental ground state deformation (${\\cal{Q}}_{20}$ = 32.8 b) is reproduced as well as the increase of t...

  2. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Mostacci, D.; Molinari, V. [Laboratorio di Ingegneria Nucleare di Montecuccolino, via dei Colli 16, 40136 Bologna (Italy); Jehouani, A. [EPRA, Department of Physics, Faculty of Sciences Semlalia, PO Box: 2390, 40000 Marrakech (Morocco)

    2010-02-15

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for {sup 252}Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect.

  3. Effect of tissue inhomogeneities on dose distributions from Cf-252 brachytherapy source.

    Science.gov (United States)

    Ghassoun, J

    2013-01-01

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. PMID:23069196

  4. Detailed dose distribution prediction of Cf-252 brachytherapy source with boron loading dose enhancement.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D; Molinari, V; Jehouani, A

    2010-02-01

    The purpose of this work is to evaluate the dose rate distribution and to determine the boron effect on dose rate distribution for (252)Cf brachytherapy source. This study was carried out using a Monte Carlo simulation. To validate the Monte Carlo computer code, the dosimetric parameters were determined following the updated TG-43 formalism and compared with current literature data. The validated computer code was then applied to evaluate the neutron and photon dose distribution and to illustrate the boron loading effect. PMID:19889549

  5. Absorption cross section measurements for 252Cf spontaneous fission neutrons (LWBR development program)

    International Nuclear Information System (INIS)

    Absolute absorption cross sections have been measured for 232Th and 197Au for 252Cf spontaneous fission neutrons. Irradiations were performed in an exceptionally low mass source-foil arrangement, providing a ''pure'' spectrum with few corrections. Calibration of the activation detector was achieved by irradiating identical foils in the National Bureau of Standards (NBS) Standard Thermal Flux. A simple ratio technique was also used to obtain an independent estimate of the relative 232Th to 197Au integral cross sections, yielding a value in good agreement with that above. This technique was extended to 181Ta, 98Mo, and 63Cu. (5 tables, 3 figures) (U.S.)

  6. In vitro activity of U-76,252 (CS-807), a new oral cephalosporin.

    OpenAIRE

    Fass, R J; Helsel, V L

    1988-01-01

    U-76,252 is the prodrug of U-76,253. MICs of U-76,253 were 0.015 to 0.06 microgram/ml for greater than or equal to 90% of the strains of Streptococcus spp., Haemophilus influenzae, and Proteus mirabilis; 0.25 to 1 microgram/ml for Branhamella catarrhalis, Escherichia coli, Klebsiella spp., and Citrobacter diversus; 1 to 8 micrograms/ml for Staphylococcus spp.; and 2 to greater than 16 micrograms/ml for other members of the family Enterobacteriaceae and Aeromonas hydrophila; for 72% of the lat...

  7. Characterization of DNA helicase II from a uvrD252 mutant of Escherichia coli.

    OpenAIRE

    Washburn, B K; Kushner, S R

    1993-01-01

    The loss of DNA helicase II (UvrD) in Escherichia coli results in sensitivity to UV light and increased levels of spontaneous mutagenesis. While the effects of various uvrD alleles have been analyzed in vivo, the proteins produced by these alleles have not been examined in any detail. We have cloned one of these alleles, uvrD252, and determined the site of the mutation conferring the phenotype. In addition, the protein it encodes has been purified to homogeneity and characterized in vitro. Th...

  8. Two-Phase Flow Measurements with 252Cf: Design Aspects and Considerations

    International Nuclear Information System (INIS)

    For many years 252Cf has been used for measuring moisture content, particularly in the ground's soil, by detecting the amount of slowing down (thermalization) of the source's fission neutrons by the hydrogen nuclei in water. The same concept has been employed for measuring the phase volume fraction in two-phase flows. Although the principle of using neutron slowing down to measure hydrogen content is basic and straightforward, its application in a confined and evolving medium such as two-phase flow can be challenging. This paper identifies some of these challenges and presents some approaches for dealing with them

  9. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    OpenAIRE

    JohnHPardue

    2014-01-01

    Biodegradation potential of MC252 in oil:sand aggregates, termed surface residue balls (SRBs), was examined using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 16-month period on the supratidal beach environment where reasonable control existed on the residence time of the aggregates on the beach surface. PAH and alkane concentration ratios were measured including PAH/C30-hopane, C2/C3 phenanthrenes, C2/C3 dibenzothiophenes...

  10. Role of energy cost in the yield of cold ternary fission of 252Cf

    Indian Academy of Sciences (India)

    P V Kunhikrishnan; K P Santhosh

    2013-01-01

    The energy costs in the cold ternary fission of 252Cf for various light charged particle emission are calculated by includingWong's correction for Coulomb potential. Energy cost is found to be higher in cold fission than in normal fission. It is found that energy cost always increases with decrease in experimental yield in all the light charged particle emissions. The higher ground state deformation of the fragments, the odd–even effect and the enhanced yield in the octupole region observed in cold fission are found to be consistent with the concept of energy cost.

  11. Target capture and target ghosts

    Science.gov (United States)

    Auerbach, Steven P.

    1996-05-01

    Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.

  12. Neutron dose rate for {sup 252} Cf AT source in medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, L.; Balcazar, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico); Francois, J.L. [FI-UNAM, 04510 Mexico D.F. (Mexico)

    2006-07-01

    The AAPM TG-43 modified protocol was used for the calculation of the neutron dose rate of {sup 252}Cf sources for two tissue substitute materials, five normal tissues and six tumours. The {sup 252}Cf AT source model was simulated using the Monte Carlo MCNPX code in spherical geometry for the following factors: a) neutron air kerma strength conversion factor, b) dose rate constant, c) radial dose function, d) geometry factor, e) anisotropy function and f) neutron dose rate. The calculated dose rate in water at 1 cm and 90 degrees from the source long axis, using the Watt fission spectrum, was D{sub n}(r{sub 0}, {theta}{sub 0})= 1.9160 cGy/h-{mu}g. When this value is compared with Rivard et al. calculation using MCNP4B code, 1.8730 cGy/h-{mu}g, a difference of 2.30% is obtained. The results for the reference neutron dose rate in other media show how small variations in the elemental composition between the tissues and malignant tumours, produce variations in the neutron dose rate up to 12.25%. (Author)

  13. Multi-modal fission in collinear ternary cluster decay of 252Cf(sf, fff

    Directory of Open Access Journals (Sweden)

    W. von Oertzen

    2015-06-01

    Full Text Available We discuss the multiple decay modes of collinear fission in 252Cf(sf, fff, with three fragments as suggested by the potential energy surface (PES. Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of 252Cf(sf into three different masses (e.g. 132–140Sn, 52–48Ca, 68–72Ni, observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions of the JINR (Dubna the collinear cluster tripartition (CCT, is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay.

  14. Feasibility of subcriticality and NDA measurements for spent fuel by frequency analysis techniques with 252Cf

    International Nuclear Information System (INIS)

    The 252Cf-source-driven frequency analysis method can be used for measuring the subcritical neutron multiplication factor of arrays of LWR fuel and as little as a single PWR fuel assembly. These measurements can be used to verify the criticality safety margins of spent LWR fuel configurations and thus could be a means of obtaining the information to justify burnup credit for spent LWR transportation/storage casks. In addition, the data can be used to validate calculational methods for criticality safety. These measurements provide parameters that have a higher sensitivity to changes in fissile mass than neutron multiplication factor and thus serve as a better test of calculational methods. The analysis have also shown that measurement of the cross power spectral density (CPSD) between detectors on one side of a single fuel assembly and an internal or external 252Cf source driving the fission chain multiplication process can be used for nondestructive assay of fissile mass along the length of the assembly. This CPSD is a smooth function of fissile mass and does not depend on the varying inherent source in the fuel assembly and thus is ideal for fissile mass assay

  15. Boron enhancement of high LET brachy-therapy using Cf-252

    International Nuclear Information System (INIS)

    The authors have used a discrete ordinates one dimensional transport code to analyse the potential enhancement of high LET event size spectra and absorbed dose around a Cf-252 implant used for treatment of glioblastoma multiforme. Toxicity effectively limits the concentration of boron in malignant brain tissues to 13-60 μg/gm at the time of treatment. Event size spectra from Cf-252 in a tissue equivalent proportional counter were used to estimate the number of high LET events per rad as a function of event size. The dose enhancement for these conditions will vary with the distance from the sources because the thermal neutron fluence is more uniform than the fast neutron fluence throughout the irradiated volume. The fast neutron dose is enhanced by as much as 60% at 5 cm., while the RBE dose enhancement is roughly 30% at this point. The number of events depositing more than 100 kev in a cell nucleus, however, is increased by at least a factor of 20 at 5 cm. These conditions will increase the effectiveness of brain tumor implants for tissues near the periphery to the extent that effective treatment depends on such high LET events

  16. New data on the fragment angular momentum in spontaneous fission of 252 Cf

    International Nuclear Information System (INIS)

    Though a considerable progress has been made in understanding the process of low-energy fission still only a little is known about the energy balance occurring at the scission point. Regarding the value of the energy that is released at the descent of the nucleus from saddle to scission only theory estimates exist. For the case of 252 Cf spontaneous fission a value of 30 MeV could be assumed for this energy release. However, the partition of this free energy remains so far the least-understood aspect of nuclear fission. Evidently, the fragment pre-scission collective motion and internal excitation degrees of freedom share a part of this energy release resulting in the pre-scission kinetic energy and pre-scission excitation of fragments. It is generally recognized that the angular momentum that fission fragments acquire in the low-energy fission is a probe for the states of excitation for some of the orthogonal angular-momentum bearing modes at the scission point. In this work the average angular momentum for primary fission fragments as a function of neutron multiplicity and neutron-to-proton ratio of the primary fission fragments was extracted for the first time for the Mo-Ba and Zr-Ce charge splits of 252 Cf. The data are discussed in terms of the energy balance occurring at the scission point. (authors)

  17. True ternary fission of 252Cf(sf), the collinear decay into fragments of similar size

    International Nuclear Information System (INIS)

    The ternary decay in 252Cf(sf, fff), with three cluster fragments of different masses (e.g.132Sn,52-48Ca,68-72Ni), has been observed by the FOBOS group in JINR. This work has established a new decay mode of heavy nuclei, the collinear cluster tripartition, (CCT). This ''true ternary fission'' of heavy nuclei has been predicted many times in theoretical works during the last decades. In the present report we discuss true ternary fission (FFF) into three nuclei of almost equal size (e.g. Z=98 → Zi = 32, 34, 32) and other fission modes in the same system. The possible fission channels for 252 Cf(sf) are predicted from potential-energy (PES) calculations. These PES's show pronounced minima for several ternary fragmentation decays, suggesting a variety of collinear ternary fission modes. The FFF-decays have very similar dynamical features as the previously observed collinear CCT-decays, the central fragment has very small kinetic energy. The data of the cited experiment allow the extraction of the yield for some FFF-decays, by using specific gates on the measured parameters

  18. GEANT4 and PHITS simulations of the shielding of neutrons from $^{252}$Cf source

    CERN Document Server

    Shin, Jae Won

    2014-01-01

    Neutron shielding simulations by using GEANT4 and PHITS code are performed. As a neutron source, $^{252}$Cf is considered and the energy distribution of the neutrons emitted from $^{252}$Cf is assumed the Watt fission spectrum. The neutron dose equivalent rates with and without the shield are estimated for shielding materials such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. For the neutron shielding simulations by using GEANT4, high precision (G4HP) model with G4NDL 4.2 based on ENDF-VII data are used. And for PHITS simulations, JENDL-4.0 library are used for the same purpose. It is found that differences between the shielding calculations by using GEANT4 with G4NDL 4.2 and PHITS with JENDL-4.0 library are not significant for all cases considered in this work. We investigate the accuracy of the neutron dose equivalent rates obtained from GEANT4 and PHITS by comparing our simulation results with experimental data and other values calculated earlier. Calculated neutron dose equivalent rates agree w...

  19. [Radiation safety during work on the ANET-V therapeutic apparatus with 252Cf sources].

    Science.gov (United States)

    Chekhonadskiĭ, V N; Drygin, V N; Vaĭnberg, M Sh; Komar, V Ia; Elisiutin, G P

    1985-03-01

    The Soviet ANET-W intracavitary neutron therapy apparatus is charged with 252Cf sources, the total mass of the radionuclide being 2100 micrograms. The radiation exposure of the staff has been studied and the results presented. Possible emergency situations have been analysed, methods of their prevention and liquidation worked out. Induced radioactivity in the patient's body has been estimated. Radiation dose levels for the medical staff are 10-15 times lower for the ANET-W apparatus than those for 252Cf sources administered by the manual series system but 10 times higher than those for the AGAT-W gamma-apparatus. The design, blocking system and emergency reset of the sources provide for safe work on the ANET-W apparatus. During liquidation of an emergency situation irradiation of the staff does not exceed 0.3 of the annual maximum tolerance dose. The level of induced activity in the patient's body is insignificant as in 10.5 min it does not exceed background values. PMID:3982256

  20. Multi-modal fission in collinear ternary cluster decay of 252Cf(sf, fff)

    International Nuclear Information System (INIS)

    We discuss the multiple decay modes of collinear fission in 252Cf(sf, fff), with three fragments as suggested by the potential energy surface (PES). Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of 252Cf(sf) into three different masses (e.g. 132–140Sn, 52–48Ca, 68–72Ni), observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions) of the JINR (Dubna) the collinear cluster tripartition (CCT), is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay

  1. Fragment angular momenta and descent dynamics in 252 Cf spontaneous fission

    International Nuclear Information System (INIS)

    Average angular momentum values of primary fission fragments as a function of neutron multiplicity and neutron-to-proton ratio were extracted for the first time for the Mo-Ba and Zr-Ce charge splittings of 252 Cf. The results are discussed in terms of the energy balance occurring at the scission point. For the first time we show that for large fragment elongation associated with larger numbers of evaporated neutrons (vtot ≥6), essentially only zero point bending oscillation takes places, i.e. T = 0 for this degree of freedom. For the major part of the fission events, with vtot = 2-5, the banding oscillation is excited to a temperature of 2-3 MeV. Such a high bending temperature implies that the coupling between the collective and internal degrees of freedom is weak at the descent of the even-even nucleus of 252 Cf to the scission point. The dipole oscillations occurring at the descent take away some 2.5 - 3.0 MeV from the release energy. A correlation between the fragment angular momentum and the mass asymmetry dependent yields of primary fragment pairs is reported. This correlation shows that the subtraction of 2.5 - 3.0 MeV from the total energy balance results in a remarkable reduction of the bending temperature. (authors)

  2. Cf-252 source-detector method for ADS and core reload in NPP's

    International Nuclear Information System (INIS)

    Accurate measurements of the subcritical level is an important research topic in the development of Accelerator Driven Systems (ADS) as well as for the determination of the subcriticality level in storage pools or during loading operations in LWR's. For ADS, it is clear that an accurate absolute determination of the subcriticality level is of paramount importance, since these systems are supposed to remain subcritical at all times. The core reload of NPP's is commonly executed by adopting the subcritical approach. This procedure allows to safely predicting the critical mass based on different subcritical states of the reactor, but it doesn't allow to obtain the subcriticality value of the different subcritical states during reload. Since practice in NPP's has shown that it would be very valuable to have access to the absolute value of the subcriticality, it is desirable to obtain a measurement technique that can be used for this purpose. In this project, we investigated the measurement of the multiplication factor keff in subcritical conditions in the VENUS reactor using the so-called 252Cf source-detector method. These measurements are the first step in the validation process of the 252Cf source-detector method to be used for subcriticality determination in ADS and during core reload in NPP's

  3. Young stellar population and ongoing star formation in the HII complex Sh2-252

    CERN Document Server

    Jose, Jessy; Samal, M R; Ojha, D K; Ogura, K; Kim, J S; Kobayashi, N; Goyal, A; Chauhan, N; Eswaraiah, C

    2013-01-01

    In this paper an extensive survey of the star forming complex Sh2-252 has been undertaken with an aim to explore its hidden young stellar population as well as to understand the structure and star formation history. This complex is composed of five embedded clusters associated with the sub-regions A, C, E, NGC 2175s and Teu 136. Using 2MASS-NIR and Spitzer-IRAC, MIPS photometry we identified 577 young stellar objects (YSOs), of which, 163 are Class I, 400 are Class II and 14 are transition disk YSOs. Spatial distribution of the candidate YSOs shows that they are mostly clustered around the sub-regions in the western half of the complex, suggesting enhanced star formation activity towards its west. Using the spectral energy distribution and optical colour-magnitude diagram based age analyses, we derived probable evolutionary status of the sub-regions of Sh2-252. Our analysis shows that the region A is the youngest (~ 0.5 Myr), the regions B, C and E are of similar evolutionary stage (~ 1-2 Myr) and the cluster...

  4. Determination of nuclear charge resolution of a thin film detector using a 252Cf fission fragment source

    International Nuclear Information System (INIS)

    Little quantitative information is available regarding the ability of a thin film detector (TFD) to determine the nuclear charge of a low energy heavy mass ion. To compare the nuclear charge resolving power Z/ΔZ of the TFD to other heavy ion detectors, an experiment was performed where the TFD luminescence response to 252Cf fission fragments was recorded in coincidence with the gamma de-excitation of the fragments. With this technique, the TFD nuclear charge resolving power Z/ΔZ was determined to be 25.2 for the light mass fragment group. (orig.)

  5. Determination of nuclear charge resolution of a thin film detector using a [sup 252]Cf fission fragment source

    Energy Technology Data Exchange (ETDEWEB)

    Milosevich, Z.; Muga, M.L. (Florida Univ., Gainesville, FL (United States). Dept. of Chemistry); Coldwell, R.L. (Florida Univ., Gainesville, FL (United States). Dept. of Physics)

    1992-09-15

    Little quantitative information is available regarding the ability of a thin film detector (TFD) to determine the nuclear charge of a low energy heavy mass ion. To compare the nuclear charge resolving power Z/[Delta]Z of the TFD to other heavy ion detectors, an experiment was performed where the TFD luminescence response to [sup 252]Cf fission fragments was recorded in coincidence with the gamma de-excitation of the fragments. With this technique, the TFD nuclear charge resolving power Z/[Delta]Z was determined to be 25.2 for the light mass fragment group. (orig.).

  6. Investigation of forming mechanism of instantaneous neutron spectrum of 235U, 239Pu, 252Cf nuclei fission

    International Nuclear Information System (INIS)

    Formation mechanism of prompt neutrons spectrum during the fission of the 235U, 239Pu nuclei by thermal and fast neutrons and spontaneous fission of 252Cf is investigated. The formation procedure for prompt neutrons spectrum during the fission of nuclei as superposition of three partial evaporation Weisskopf spectra with the mean energy of neutrons 0.4, 2.06 and 2.8 MeV is proposed. Formation mechanism of the spectrum just as during the fission of the 235U, 239Pu nuclei by thermal and fast neutrons, so spontaneous fission of the 252Cf nuclei is identical

  7. On the use of a ({sup 252}Cf-{sup 3}He) assembly for landmine detection by the neutron back-scattering method

    Energy Technology Data Exchange (ETDEWEB)

    Elsheikh, N., E-mail: nassreldeen.elsheikh@yahoo.com [College of Applied and Industrial Science, Department of Physics, University of Juba, Khartoum, P.O. Box 12327/1 (Sudan); Viesti, G. [Dipartimento di Fisica ed Astronomia dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); ElAgib, I. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia); Habbani, F. [Faculty of Science, Physics Department, University of Khartoum, Khartoum, P.O. Box 321 (Sudan)

    2012-04-15

    Experiments were carried out to optimize the performance of the neutron back-scattering (NBS) technique in landmine detection using an assembly consisting of three different layers placed above a {sup 252}Cf neuron source, producing about 10{sup 4} s{sup -1}, in conjunction with a {sup 3}He detector. The assembly was optimized experimentally. The selected assembly configuration was then examined against different {sup 252}Cf stand-off distances and mine burial depths using dummy landmines. Furthermore, Monte Carlo simulations were performed to study the effect of the shield when a {sup 252}Cf source in the range 10{sup 4}-10{sup 7} s{sup -1} was employed, and to optimize the geometry for future prototypes. - Highlights: Black-Right-Pointing-Pointer A suitable shielded ({sup 252}Cf-{sup 3}He) assembly for landmine detection was developed. Black-Right-Pointing-Pointer Experimental tests and MCNP simulations were performed for a {sup 252}Cf of (10{sup 4}-10{sup 7})s{sup -1}. Black-Right-Pointing-Pointer Experimental and MCNP results for {sup 252}Cf of 10{sup 4}s{sup -1} supports the use of the shield. Black-Right-Pointing-Pointer MCNP Results recommends {sup 252}Cf of 10{sup 6}s{sup -1} for hand-held detection system. Black-Right-Pointing-Pointer MCNP Results recommends {sup 252}Cf of 10{sup 7}s{sup -1} for a robotic detection system.

  8. 47 CFR 51.807 - Arbitration and mediation of agreements by the Commission pursuant to section 252(e)(5) of the Act.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Arbitration and mediation of agreements by the... Implementation of Section 252 of the Act § 51.807 Arbitration and mediation of agreements by the Commission... proceeding or matter. (c) In resolving, by arbitration under section 252(b) of the Act, any open issues...

  9. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  10. 7 CFR 1726.252 - Prior approved contract modification related to liability for special and consequential damages.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Prior approved contract modification related to... Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE ELECTRIC SYSTEM CONSTRUCTION POLICIES AND PROCEDURES Modifications to RUS Standard Contract Forms § 1726.252 Prior...

  11. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Economic price adjustment... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions And Clauses 252.216-7000 Economic price...), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  12. 48 CFR 252.226-7001 - Utilization of Indian organizations, Indian-owned economic enterprises, and native Hawaiian small...

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Utilization of Indian... Clauses 252.226-7001 Utilization of Indian organizations, Indian-owned economic enterprises, and native Hawaiian small business concerns. As prescribed in 226.104, use the following clause: Utilization of...

  13. The temperature of fission fragments from spontaneous fission of 252Cf measured by time-of-flight spectrometer

    International Nuclear Information System (INIS)

    The detection system MONA (Modular Neutron Array) consisting of eight large BC-501A liquid scintillators, was applied to determine the temperature of fission fragments emitted in spontaneous fission of 252Cf. The determination of the temperature was based on the measurement of the neutron spectra

  14. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Science.gov (United States)

    2010-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Innovation Research (SBIR) Program. As prescribed in 227.7104(a), use the following clause: Rights in Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (JUN...

  15. Numerical Simulation of Gas Flow During Arcing Process for 252 kV Puffer Circuit Breakers

    Science.gov (United States)

    Wu, Junhui; Wang, Xiaohua; Ma, Zhiying; Rong, Mingzhe; Yan, Jing

    2011-12-01

    A numerical simulation model for 252 kV puffer circuit breaker is constructed, by using a proven commercial computational fluid dynamics (CFD) package, PHOENICS. The model takes into account the moving parts in the circuit breaker, turbulence enhanced momentum and energy transport, radiation transport. The arcing process in a SF6 puffer circuit breaker with two hollow contacts is simulated under different conditions, and the simulation results are verified with experimental results. Through simulation, the pressure, temperature and velocity in the arc quenching chamber can be obtained. The simulation model is also capable of predicting the influence of design parameters variations on breaker performance, and can thus help to reduce the number of short-circuit tests during the design stage.

  16. The chemical states of tellurium produced by spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    The distribution of the chemical states of tellurium isotopes produced by 252Cf spontaneous fission, collected separately in the matrixes of NaCl, Kl, NaF, CH3COONa x 3H2O, Na2SO4 and NaNO3 crystals was investigated. Two chemical states of tellurium isotopes maintained in these matrixes are Te(IV) and Te(VI). The relationships between the distribution of the chemical states of tellurium isotopes and the produced mode of tellurium, the chemical properties of collection matrixes, the time for collecting fission fragments are studied and the possible mechanism of the interactions of the fission products and the matrixes is discussed. The results show that the distribution of chemical states of tellurium isotopes depends primarily on the chemical properties of the collection matrixes. (author) 18 refs.; 2 figs.; 10 tabs

  17. Investigation of the prompt-neutron spectrum for spontaneously-fissioning 252Cf

    International Nuclear Information System (INIS)

    The prompt-fission-neutron spectrum of 252Cf was investigated. The spectrum was measured with Black Neutron Detectors which have a well known efficiency. Considerations of various issues in such measurements lead to an experiment in which a time-calibration pulser, a random pulser, the neutron detector time-of-flight spectrum, the pulse-shape-discriminator gamma time-of-flight spectrum, and the detector-response spectra were simultaneously recorded for the prompt-fission neutrons, transmission through carbon, and shadowbars in a total-cross-section-type measurement. Corrections and associated uncertainties were applied for a large variety of effects which may have been overlooked in many of the previously reported measurements. Preliminary results indicate deviations from a Maxwellian shape toward a Watt-spectrum shape. Agreement is good with the shape differences relative to a Maxwellian from the recent theoretical calculation by Madland and Nix, however, a lower average energy was found

  18. Characteristics of the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators

    International Nuclear Information System (INIS)

    The authors established the simulated workplace neutron fields using a 252Cf source surrounded with cylindrical moderators at the Japan Nuclear Cycle Development Inst. (JNC), Tokai Works. The moderators are annular cylinders made of polymethyl methacrylate and steel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP-4B and the measurements by the Bonner multisphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields can provide the realistic neutron spectra similar to those encountered around the glove-boxes of the fabrication process of MOX (PuO2-UO2 mixed oxide) fuel. (authors)

  19. Metronidazole in the treatment of cervical cancer using Cf-252 neutron brachytherapy

    International Nuclear Information System (INIS)

    Metronidazole was tested for its possible use in the Cf-252 brachytherapy of cervical cancer as a radiosensitizer and to deal with anaerobic pelvic infection. 15 patients were treated by only 14 were evaluable. All stages from stage IB-IVB were treated and complete local tumor regression was noted in all cases although it could take place very slowly. 5/14 (36%) are 1.5-3 year survivors but only among the patients with stage I-II disease. No unusual radio-enhancing action was observed but metronidazole appeared to be useful to treat the vaginal, cervix and uterine infections often associated with high stage disease and bulky, ulcerative or necrotic tumors

  20. Depth dose distribution for sup 252 Cf source using solid state detectors

    Energy Technology Data Exchange (ETDEWEB)

    Moustafa, H.R.; Mohamed, R.L. (Al Azhar Univ. of Girls, Cairo (Egypt). Physics Dept.); Abdel-Wahab, M.S.; El Fiki, S.; El Enany, N. (Ain Shams Univ., Cairo (Egypt). Dept. of Physics); Eissa, H.M.; El Feky, M.A. (National Inst. for Standards, Cairo (Egypt). Academy of Scientific Research and Technology)

    1991-01-01

    LiF (600 and 700) and solid state nuclear track detectors were used for measuring fast and thermal neutrons and {gamma}-ray doses from {sup 252}Cf source in tissue equivalent phantom. Conversion factors as well as related quality factors were used for absorbed and equivalent dose calculations. Two exposure positions were used: Source at 30 cm and in contact with phantom surface. The contribution of thermal and fast neutrons in both absorbed dose and equivalent dose reaches a maximum value at 3.5 cm while the maximum for {gamma}-ray is at 8.5 cm. The build up and attenuation in tissue and the corresponding relaxation length were evaluated. (orig.).

  1. Beta decay of 252Cf on the way to scission from the exit point

    CERN Document Server

    Pomorski, K; Quentin, P

    2015-01-01

    Upon increasing significantly the nuclear elongation, the beta-decay energy grows. This paper investigates within a simple yet partly microscopic approach, the transition rate of the beta decay of the 252Cf nucleus on the way to scission from the exit point for a spontaneous fission process. A rather crude classical approximation is made for the corresponding damped collective motion assumed to be one dimensional. Given these assumptions, we only aim in this paper at providing the order of magnitudes of such a phenomenon. At each deformation the energy available for beta decay, is determined from such a dynamical treatment. Then, for a given elongation, transition rates for the allowed (Fermi) beta decay are calculated from pair correlated wave functions obtained within a macroscopic-microscopic approach and then integrated over the time corresponding to the whole descent from exit to scission. The results are presented as a function of the damping factor (inverse of the characteristic damping time) in use in...

  2. Shielding of radiation fields generated by 252Cf in a concrete maze. Part 2 -- Simulation

    International Nuclear Information System (INIS)

    A streaming experiment performed in a concrete maze of shape and size typical of a radiotherapy room was simulated with the Monte Carlo program FLUKA. The purpose of the calculation was to test the performance of the code in the low energy neutron range, and at the same time to provide additional information which could help in optimizing shielding of medical facilities. Instrument responses were calculated at different maze locations for several experimental configurations and were compared with measurements. In addition, neutron and gamma fluence, ambient dose equivalent and effective dose were calculated at the same positions. Both sources used in the experiment, namely a bare 252Cf source and one shielded by a tungsten shell 5 cm thick, were considered in the simulation

  3. Numerical Simulation of Gas Flow During Arcing Process for 252 kV Puffer Circuit Breakers

    International Nuclear Information System (INIS)

    A numerical simulation model for 252 kV puffer circuit breaker is constructed, by using a proven commercial computational fluid dynamics (CFD) package, PHOENICS. The model takes into account the moving parts in the circuit breaker, turbulence enhanced momentum and energy transport, radiation transport. The arcing process in a SF6 puffer circuit breaker with two hollow contacts is simulated under different conditions, and the simulation results are verified with experimental results. Through simulation, the pressure, temperature and velocity in the arc quenching chamber can be obtained. The simulation model is also capable of predicting the influence of design parameters variations on breaker performance, and can thus help to reduce the number of short-circuit tests during the design stage. (15th asian conference on electrical discharge)

  4. Gamma-ray studies of the spontaneous fission of 242Pu and 252Cr using gammasphere

    International Nuclear Information System (INIS)

    The authors report on the new results on 242Pu and 252Cf spontaneous fission gamma-rays with emphasis on the dependence of spin distributions on numbers of neutrons emitted. The analysis has concentrated first on extracting relative intensities of ground rotational transitions as a function of number of neutrons emitted. open-quotes Cold fissionclose quotes, or zero-neutron fission, is observed in a number of fissioning systems. Some isotopic series show a trend of decreasing fragment average spin with increasing numbers of neutrons emitted, contrary to the initial expectations of a simple quantal model based on neck thickness expected at scission. A simple open-quotes atomic orbitalclose quotes model plus Coulomb excitation is compared with the data. Preliminary results from an April 1994 run using 36 Ge detectors in Early Implementation of Gammasphere coupled with 4 neutron detectors and 1 X-ray detector are shown

  5. Effect of tissue Inhomogeneities on dose distributions from Cf-252 brachytherapy source

    International Nuclear Information System (INIS)

    The Monte Carlo method was used to determine the effect of tissue inhomogeneities on dose distribution from a Cf-252 brachytherapy source. Neutron and gamma-ray fluences, energy spectra and dose rate distributions were determined in both homogenous and inhomogeneous phantoms. Simulations were performed using the MCNP5 code. Obtained results were compared with experimentally measured values published in literature. Results showed a significant change in neutron dose rate distributions in presence of heterogeneities. However, their effect on gamma rays dose distribution is minimal. - Highlights: ► The effect of tissue inhomogeneities on dose distribution has been investigated. ► A comparison of our results with experimental data available in the literature is presented. ► Obtained results showed a significant change in neutron dose rate distributions.

  6. Search for scission neutrons in the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    In the spontaneous fission of 252Cf, we observed that the population of spin 2+ in 136Te is closely correlated with the population of spin 4+ of its partner 114Pd. We attribute our results to the emission of two neutrons at scission carrying away two units of angular momentum and the yield is 0.06(2) per 100 spontaneous fission (SF) events whereas the two neutron normal fission yield is 0.12(3) per 100 SF for the 136Te and 114Pd pair. The yield for fission with four scission neutrons for 136Te and 112Pd is observed to be ∼0 whereas the four neutron hot fission yield is 0.28(4) per 100 SF events. copyright 1999 The American Physical Society

  7. Investigation of the prompt-neutron spectrum for spontaneously-fissioning /sup 252/Cf

    Energy Technology Data Exchange (ETDEWEB)

    Poenitz, W.P.; Tamura, T.

    1982-01-01

    The prompt-fission-neutron spectrum of /sup 252/Cf was investigated. The spectrum was measured with Black Neutron Detectors which have a well known efficiency. Considerations of various issues in such measurements lead to an experiment in which a time-calibration pulser, a random pulser, the neutron detector time-of-flight spectrum, the pulse-shape-discriminator gamma time-of-flight spectrum, and the detector-response spectra were simultaneously recorded for the prompt-fission neutrons, transmission through carbon, and shadowbars in a total-cross-section-type measurement. Corrections and associated uncertainties were applied for a large variety of effects which may have been overlooked in many of the previously reported measurements. Preliminary results indicate deviations from a Maxwellian shape toward a Watt-spectrum shape. Agreement is good with the shape differences relative to a Maxwellian from the recent theoretical calculation by Madland and Nix, however, a lower average energy was found.

  8. Clusters in true ternary fission in the 252Cf (Sf) reaction

    International Nuclear Information System (INIS)

    In the paper effect of the formation of clusters on production of the true ternary fission at simultaneous fission of 2'52Cf is investigated. Unlike conventional ternary fission with the emission of the alpha particle and binary fission, in true ternary fission reaction products are observed with the comparable masses and charges. By studying the potential energy surface calculated for the ternary system before splitting, charge and mass distributions of the nascent products at the spontaneous fission of 252Cf are estimated. Probabilities of the true ternary fission products will be greater where the potential energy surface has minima deeper. Results showed that the products of true ternary fission with magical numbers 20, 28, 50 and 82 for protons and neutrons are formed with a high probability. (authors)

  9. Fragment angular momentum and descent dynamics in 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    Fragment angular momenta as a function of neutron multiplicity were extracted for the first time for the Mo-Ba and Zr-Ce charge splits of 252Cf by studying prompt coincident γ-rays. The obtained primary fragment angular momenta do not continuously rise with the increase in the number of neutrons evaporated. In frame of the scission point bending oscillation model such regularity is explained due the decrease of the bending temperature. Adiabatic bending oscillations (T=0) are obtained at large (νtot>5) and small (νtot=0) scission point elongation. These oscillations are excited to the temperature of 2-3 MeV for the most probable scission configurations indicating a weak coupling between collective and internal degrees of freedom. A strong coupling between the collective bending and dipole oscillations was found

  10. Fragment angular momentum and descent dynamics in 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    Fragment angular momenta as a function of neutron multiplicity were extracted for the first time for the Mo-Ba and Zr-Ce charge splits of 252Cf by studying prompt coincident γ-rays. The obtained primary fragment angular momenta do not continuously rise with the increase in the number of neutrons evaporated. In frame of the scission point bending oscillation model such regularity is explained due the decrease of the bending temperature. Adiabatic bending oscillations (T=0) are obtained at large (νtot>5) and small (νtot=0) scission point elongation. These oscillations are excited to the temperature of 2 - 3 MeV for the most probable scission configurations indicating a weak coupling between collective and internal degrees of freedom. A strong coupling between the collective bending and dipole oscillations was found. copyright 1998 American Institute of Physics

  11. Relative Yields of 149-153Pr in Spontaneous Fission of 252Cf

    Science.gov (United States)

    Eldridge, Jonathan; Wang, Enhong; Hwang, J. K.; Hamilton, Joe; Ramayya, A. V.; Luo, Y. X.; Rasmussen, J. O.; Zhu, S. J.; Liu, S. H.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.

    2013-10-01

    The relative yields of the fission partners of 149-153Pr, resulting from the spontaneous fission of 252Cf, were studied. This study was done by means of γ - γ - γ , and γ - γ - γ - γ coincidence data taken in 2000 by the multi-HPGe, Compton-suppressed, gamma detector array, Gammasphere, at Lawrence Berkeley National Lab. The coincidence data were analyzed by double- and triple-gating on transitions in 149-153Pr and obtaining the intensities of the 93-101Y transitions. For 150 , 151 , 152 , 153Pr the 3n channel was found to be the strongest. The 149Pr, however, was found to peak at the 4n channel. These results were used to verify the assignments of the level schemes of 151 , 152 , 153Pr. The data are found to be in agreement with Wahl's independent yield tables.

  12. High energy γ emission in the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    The prompt γ emission in the spontaneous fission of 252Cf is characterized by an energy spectrum which extends up to 20 MeV. It was established that the spectrum presents in the neighbourhood of symmetric fission an intensity bump in the 3-8 MeV γ energy interval. The origin of this phenomenon is still not well understood, so that it was found interesting to carry out new measurements. The spectrum of the γ rays emitted in spontaneous fission of 252Cf has been measurement in the EUROGAM II multidetector using photovoltaic cells to detect fragments. The aim of the experiment was to investigate the γ yield enhancement which appears for mass fragment ratio near 132/120. This enhancement was found to be composed of two peaks located at 4 MeV and 5.5 MeV respectively. The results obtained confirm the intensity bound in the 3-8 MeV region but this augmentation reaches the maximum when the heavy fragment is near the mass 132. Beyond mass 140 the phenomenon diminish and the γ spectrum regains the behaviour expected for a statistic emission. The additional structure at 5.5 MeV does not vary with excitation energy while the excitation function of the 4 MeV structure is more structured and presents a maximum when the excitation energy is near 8 MeV. It is likely that all or part of this observed phenomenon is due to a particular excitation mode of this isotope associated for instance with a low energy dipole resonance. A theoretical study of this collective effect is under way

  13. Accurate plutonium waste measurements using the 252Cf add-a- source technique for matrix corrections

    International Nuclear Information System (INIS)

    We have developed a new measurement technique to improve the accuracy and sensitivity of the nondestructive assay (NDA) of plutonium scrap and waste. The 200-ell drum assay system uses the classical NDA method of counting passive-neutron coincidences from plutonium but has added the new features of ''add-a-source'' to improve the accuracy for matrix corrections and statistical techniques to improve the low-level detectability limits. The add-a-source technique introduces a small source of 252Cf (10-8 g) near the external surface of the sample drum. The drum perturbs the rate at which coincident neutrons from the 252Cf are counted. The perturbation provides the data to correct for the matrix and plutonium inside the drum. The errors introduced from matrix materials in 200-ell drums have been reduced by an order of magnitude using the add-a-source technique. In addition, the add-a-source method can detect unexpected neutron-shielding material inside the drum that might hide the presence of special nuclear materials. The detectability limit of the new waste-drum assay system for plutonium is better than prior systems for actual waste materials. For the in-plant installation at a mixed-oxide fabrication facility, the detectability limit is 0.73 mg of 24OPu (or 2.3 mg of high-burnup plutonium) for a 15-min. measurement. For a drum containing 100 kg of waste, this translates to about 7 nCi/g. This excellent sensitivity was achieved using a special low-background detector design, good overhead shielding, and statistical techniques in the software to selectively reduce the cosmic-ray neutron background

  14. PIXE, 252Cf-PDMS and radiochemistry applied for soil and vegetable analysis

    International Nuclear Information System (INIS)

    The aim of this work is to identify the elements present in vegetables and soils using PIXE (particle induced X-rays emission) and 252Cf-PDMS (252Cf plasma desorption mass spectrometry) techniques in order to estimate the possible influence of soil and agricultural techniques in the metal absorption by the vegetables. In this work, metal concentrations were evaluated in soil and vegetable samples from several regions, where different agricultural techniques were employed. Si, Zr, Ce, Th, Sc and Pb identified in the soil samples were not biologically available. Ga, Ge, As and Br identified in the tubercles indicate that spray pesticide used on the vegetable leaves was absorbed by them. 232Th and 238U present in the soil were not absorbed by the vegetables. The airborne particles from anthropogenic sources (as CFn, VCn) were absorbed by the vegetables. Compounds from mineral sources present in soil as V+, VCO3, HPO4, Cr+, CrOH+, Mn+, FeH+, Fe(OH)n and in the bioorganic compounds as N+, Ca(China)n+ and CnH+ were identified in vegetables. The metal absorption by the vegetables is not dependent of the metal concentration in soil. Different tubercles cultivated in the same soil show similar metal absorption. The exogenous contributions such as the elements present in water irrigation, pesticides, fertilizers and airborne particles deposited on leaves can be absorbed by vegetables. The absorption by the roots depends on the chemical compound of the elements. The use of pesticide sprays and air pollution can cause more contamination in the vegetables than in soil. The use of this methodology allows the identification of possible sources of metals in soils and in vegetables and the metal speciation

  15. Study of the isomer nuclei produced in the spontaneous fission of {sup 252}Cf; Etude des noyaux isomeriques produits dans la fission spontanee de {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C.; Houry, M.; Korten, W.; Le Coz, Y.; Lucas, R.; Thiesen, Ch. [Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee, CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Badimon, C.; Barreau, G.; Doan, T.P.; Pedemay, G. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Belier, G.; Girod, M.; Meot, M.V. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, G.; Meot, V.; Peru, S. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France); Astier, A.; Ducroux, L.; Meyer, M.; Redon, N. [Inst.de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1997-06-01

    Isomeric states have been studied in fission fragments produced by spontaneous fission of {sup 252}Cf. 34 isomeric nuclei have been identified by using coincidences between {gamma}-rays detected in EUROGAM II and fission fragments detected in photovoltaic cells. Lifetimes from 20 ns up to 2 {mu}s have been measured. Microscopic interpretation of the isomeric levels discovered has been tried by means of the Hartree-Fock-Bogolyubov procedure using Gogny force. It was found that the {sup 152,154,156}Nd nuclei have prolate deformation in their ground state; the rotational band built on this ground state is well reproduced by the calculation. For these nuclei the 2 quasi-particle excited states energies are above 1 MeV in agreement with the experiment. The computation confirms the similitude of the {sup 156}Nd and {sup 158}Sm isomeric states associated to neutron 2 quasi-particles of J{sup {pi}} K{sup {pi}} = 5{sup -} ({nu} 5/2 (642) x {nu} 5/2 (523)) while such similitude does not occur for the isotone nuclei {sup 154}Nd and {sup 156}Sm. The computation predicts a proton 2 quasi-particle excited states of J{sup {pi}} = 5{sup -}, near the isomeric level measured in {sup 156}Sm but not for that of {sup 154}Nd. Concerning the {sup 152}Nd the calculated level density is very near that of the states measured in the 1.6 to 2.3 MeV interval. However, the lack of precise information on spins and parities of the measured levels does make not possible a confrontation with the calculations. An up-graded equipment implying 32 photovoltaic cells instead of 2 cells is to be developed and installed by the EUROGAM 3 refs.

  16. Study of micronucleus induction in the root-tip cells of onion seedlings after irradiation as dry dormant seeds by 252Cf fission neutrons

    International Nuclear Information System (INIS)

    The work is for a better understanding of relative biological effectiveness (RBE) of 252Cf fission neutrons. The frequency of micronuclei induced in the root-tip cells of onion seedlings after irradiation as dry dormant seeds by unit dose of 252Cf neutron-γ mixed irradiation is different from that by 60Co γ-ray irradiation. The frequency of micronuclei induced by unit dose of 252Cf neutron-γ mixed irradiation and 60Co γ-ray irradiation are 1.84 ± 0.10 and 0.022 ± 0.002 (%Gy-1), respectively; and the frequency of micronuclei induced by unit dose of 252Cf fission neutrons is 2.74 ± 0.15 (%Gy-1). The RBE values for 252Cf neutron-γ mixed irradiation and 252Cf fission neutrons are 84 ± 9 and 124 ± 13, respectively. The frequency of micronuclei induced in the root-tip cells of Allium cepa onion seedlings irradiated as dry dormant seeds by unit dose of 252Cf neutron-γ mixed irradiation is about 84 times as that by 60Co γ-ray irradiation. The findings suggested that repair efficiency of DNA damage induced by neutrons might be different from that by γ-ray. (authors)

  17. Targeted Learning

    CERN Document Server

    van der Laan, Mark J

    2011-01-01

    The statistics profession is at a unique point in history. The need for valid statistical tools is greater than ever; data sets are massive, often measuring hundreds of thousands of measurements for a single subject. The field is ready to move towards clear objective benchmarks under which tools can be evaluated. Targeted learning allows (1) the full generalization and utilization of cross-validation as an estimator selection tool so that the subjective choices made by humans are now made by the machine, and (2) targeting the fitting of the probability distribution of the data toward the targe

  18. Long repair replication patches are produced by the short-patch pathway in a uvrD252 (recL152) mutant of Escherichia coli K-12.

    OpenAIRE

    Rothman, R H; Fried, B

    1984-01-01

    The uvrD252 mutation leads to increased UV sensitivity, diminished dimer excision and host cell reactivation capacity, and an increase in the average patch size after repair replication. A recA56 uvrD252 double mutant was far more resistant to UV than was a recA56 uvrB5 double mutant. Its host cell reactivation capacity was identical to that of uvrD252 single mutant and was far greater than that of the uvrB5 single mutant. The strain showed no Weigle reactivation. From these results, we concl...

  19. Prompt neutron multiplicity in correlation with fragments from spontaneous fission of 252Cf

    Science.gov (United States)

    Göök, A.; Hambsch, F.-J.; Vidali, M.

    2014-12-01

    The spontaneous fission of 252Cf serves as an excellent benchmark of prompt emission in fission since experimental data can be obtained without the need of an incident beam. With the purpose of providing experimental data on the prompt fission neutron properties in correlation with fission-fragment characteristics, an experiment on 252Cf(SF) has been performed. In addition, the experiment serves as a benchmark of setup and analysis procedures for measurements of fluctuations in the prompt-neutron properties as a function of incident neutron energy in fission of the major actinides 235U and 239Pu. The experiment employs a twin Frisch grid ionization chamber as fission-fragment detector while neutrons were counted by using a liquid scintillator placed along the symmetry axis of the ionization chamber. Average neutron multiplicity has been obtained as a function of fission-fragment mass and total kinetic energy (TKE). The average multiplicity as a function of mass agrees well with available data in the literature in the mass range from 80 to 170 u. The existence of additional sawtooth structures in the far asymmetric mass region could not be confirmed, although the statistical accuracy of the present experiment is as good as the previous study where such structures have been reported [Nucl. Phys. A 490, 307 (1988)., 10.1016/0375-9474(88)90508-8]. The available data in the literature on the TKE dependence of the multiplicity show strong deviations. Therefore, effort was focused on investigating experimental factors in low-efficiency neutron-counting experiments that may lead to faulty determination of this dependence. Taking these factors into account, a result that agrees well with data from high-efficiency neutron-counting experiments is obtained. The experimental arrangement allows determination of the angle between the detected neutron and the fission axis, which permits the neutron properties to be transformed into the fission-fragment rest frame. Fission neutron

  20. A Monte Carlo simulation and setup optimization of output efficiency to PGNAA thermal neutron using 252Cf neutrons

    Science.gov (United States)

    Zhang, Jin-Zhao; Tuo, Xian-Guo

    2014-07-01

    We present the design and optimization of a prompt γ-ray neutron activation analysis (PGNAA) thermal neutron output setup based on Monte Carlo simulations using MCNP5 computer code. In these simulations, the moderator materials, reflective materials, and structure of the PGNAA 252Cf neutrons of thermal neutron output setup are optimized. The simulation results reveal that the thin layer paraffin and the thick layer of heavy water moderating effect work best for the 252Cf neutron spectrum. Our new design shows a significantly improved performance of the thermal neutron flux and flux rate, that are increased by 3.02 times and 3.27 times, respectively, compared with the conventional neutron source design.

  1. Photoreactivation of ICR 2A frog cells after exposure to monochromatic ultraviolet radiation in the 252-313 nm range

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to photoreactivating light after treatment with monochromatic ultraviolet (UV) radiation in the 252-313nm range resulted in an increase in survival with similar photoreactivable sectors for each of the wavelengths tested. As photoreactivating enzyme is specific for the repair of pyrimidine dimers in DNA, these findings support the hypothesis that these are critical lesions responsible for killing of cells exposed to UV radiation in this wavelength range. The action spectra for cell killing and production of UV-endonuclease sensitive sites were similar to the DNA absorption spectrum though not identical. Because the number of endonuclease sensitive sites is a reflection of the yield of pyrimidine dimers, these data also suggest that the induction of dimers in DNA by UV radiation in the 252-313 nm range is the principle event leading to cell death. (author)

  2. A comparison of dosimetric parameters and dose distribution around CF -252 and IR-192 LDR Brachytherapy Sources

    International Nuclear Information System (INIS)

    Full text: The purpose of this work is the evaluation and comparison of the dose rate distributions around a 252Cf Applicator Tube (AT) and 192Ir LDR sources. The dosimetric parameters were determined for both sources according to the updated AAPM TG-43U1 protocol. The calculations were performed using the Monte Carlo N-particle MCNP code, version 5C. To validate the results of this study, they were compared to experimental and analytical dosimetric data available in the literature for similar source configurations. After validation, the Monte Carlo computer code was applied to investigate the difference between dose rate distributions around the two brachytherapy sources, with the purpose of comparing their efficiency in treatment. The data so obtained also provide further information about spatial dose distributions and are important for detailed treatment planning with 252 Cf or 192Ir LDR sources for interstitial and intracavitary therapy

  3. Absolute measurement of anti ν/sub p/ for 252Cf using the ORNL large liquid scintillator neutron detector

    International Nuclear Information System (INIS)

    The ORNL large liquid scintillator detector was used in a precise determination of anti ν/sub p/, the number of neutrons emitted promptly, for spontaneous fission of 252Cf. Measurements of the detector efficiency over a broad energy region were made by means of a proton-recoil technique employing the ORELA white neutron source. Monte Carlo calculation of the detector efficiency for a spectrum representative of 252Cf fission neutrons was calibrated with these elaborate measurements. The unusually flat response of the neutron detector resulted in elimination of several known sources of error. Experimental measurement was coupled with calculational methods to correct for other known errors. These measurements lead to an unusually small estimated uncertainty of 0.2% in the value obtained, anti ν/sub p/ = 3.773 +- 0.007

  4. Pre-scission configuration of the tri-nuclear system at spontaneous ternary fission of 252Cf

    Science.gov (United States)

    Nasirov, A. K.; Tashkhodjaev, R. B.; von Oertzen, W.

    2016-05-01

    The potential energy surface for the pre-scission configurations of tri-nuclear systems formed in the spontaneous ternary fission of 252Cf is calculated. The fission channel 70Ni + 50Ca + 132Sn is chosen as one of the more probable channels of true ternary fission of 252Cf . A study of the collinear arrangement of the reaction products for true ternary fission is the aim of this work. The results are presented as a function of the relative distance R12 between the centres of mass of 70Ni and 132Sn and the distance from the centre of mass of 50Ca , which is perpendicular to R12. The results show that only for a particular range of the R12 values the collinear tripartion of the fissioning nucleus occurs.

  5. HeLa cell tumor response to 60Co, Cs-137, Cf-252 radiations and cisplatin chemotherapy in nude mice

    International Nuclear Information System (INIS)

    HeLa cells were implanted into athymic nude mice from tissue culture and solid tumors established (HeLa cell tumor or HCT). Large cell numbers of 1 X 107 were required to obtain consistent and progressive growth, and tumor growth followed a Gompertzian mode. Irradiation studies were carried out using acute Cobalt-60 (60Co), low-dose-rate (LDR) Cs-137 and LDR Cf-252. Cf-252, a neutron-emitting radioisotope, produced an immediate tumor shrinkage and regression response after a dose of 279 cGy. Acute 60Co or LDR Cs-137 irradiation with 1000 cGy had little effect on the HCT. After a dose of 2000 cGy of 60Co radiation tumor shrinkage followed a latent period of approximately 5 days. Cisplatin had no effect on the HCT in nude mice in stationary or late exponential growth

  6. Effects of Exposure of Pink Shrimp, Farfantepenaeus duorarum, Larvae to Macondo Canyon 252 Crude Oil and the Corexit Dispersant

    OpenAIRE

    Susan Laramore; William Krebs; Amber Garr

    2016-01-01

    The release of oil into the Gulf of Mexico (GOM) during the Deepwater Horizon event coincided with the white and pink shrimp spawning season. To determine the potential impact on shrimp larvae a series of static acute (24–96 h) toxicity studies with water accommodated fractions (WAFs) of Macondo Canyon (MC) 252 crude oil, the Corexit 9500A dispersant, and chemically enhanced WAFS (CEWAFs) were conducted with nauplii, zoea, mysid, and postlarval Farfantepenaeus duorarum. Median lethal concentr...

  7. OER by survival time for Cf-252, low dose rate Cs-137 and acute Co-60 for LSA lymphoma

    International Nuclear Information System (INIS)

    RBE and OER were determined for LSA tumor by survival time assay. The RBEn of Cf vs. Cs-137 was 5.8 and the OER was ∼ 1.4 by experiments performed in vitro and assayed in vivo. When tumor was irradiated in an advanced state in the living mouse, the RBEn was determined to be 5.2 vs. Cs-137. The RBE for hypoxic tumor is larger than for the oxic tumor for Cf-252 neutron irradiation. (Auth.)

  8. Measurement of the neutron spectrum and ambient neutron dose rate equivalent from the small 252Cf source at 1 meter

    International Nuclear Information System (INIS)

    NASA Langley Research Center requested a measurement of the neutron spectral distribution and fluence from the 252Cf source (model NS-120, LLNL serial # 7001677, referred as the SMALL Cf source) and determination of the ambient neutron dose rate equivalent and kerma at 100 cm for the Radiation Budget Instrument Experiment (Rad-X). The dosimetric quantities should be based on the neutron spectrum and the current neutron-to-dose conversion coefficients.

  9. 252Cf spontaneous prompt fission neutron spectrum measured at 0 degree and 180 degree relative to the fragment motion

    International Nuclear Information System (INIS)

    The 252Cf spontaneous prompt fission neutron spectrum at 0 degree and 180 degree relative to the motion direction of corresponding fission fragments was measured. High angular resolution for fragment measurements and high energy resolution for neutron measurements were obtained using multi-parameter TOF spectrometer. The results showed that there is a symmetric distribution of 'forward' and 'backward' for low energy in C.M.S. neutrons, which was an evidence of nonequilibrium neutrons existed in fission process

  10. Dicentric yields induced in rabbit blood lymphocytes by low doses of 252Cf neutrons

    International Nuclear Information System (INIS)

    Little dose-response data for dicentrics induced in blood lymphocytes exposed in the low dose-range to fast neutrons in vitro has been reported. This experiment was carried out to obtain the dose-response equation for dicentrics, in the dose range below 20 mGy, (needed in the event of an accidental exposure to neutrons). Rabbit blood lymphocytes were exposed in vitro to 252Cf neutron of mean energy 2.35 MeV. The dose range was 2-20 mGy delivered at dose-rate of 0.145-0.31 mGy/min. The dose-response equation for dicentrics was calculated by the linear regression analysis. The present experimental data was compared with the data, in the low dose range below 50 mGy, reported by other authors. Maximum value of RBE with respect to 150 kVp X-rays was 40, and it was founded in this experiment that the RBE values were dose dependent, the lower or the higher than about 13 mGy the doses, the smaller RBE values, with the maximum value occurring at about 13 mGy. (author)

  11. Design and construction of an explosive detection system by Tna methods, using 252Cf radioisotope source

    International Nuclear Information System (INIS)

    Bombs concealed in luggage have threatened human life and property throughout the world's traffic. The plastic explosives could not checked by the X-ray detecting device. Thermal Neutron Activation method has been tested in the present work for non-destructive detection of explosives. A radioisotope neutron source 252Cf and two gamma spectroscopy systems have been used as a tool to find explosives, regardless of the bomb's shape and the packing materials. The MCNP code has been used to design the neutronic section of the system. The measured thermal neutron fluxes by the gold foils in some location of the system were in good agreement with those data obtained by the MCNP code. Also, detection limits for nitrogen in various counting times were measured. The measurements show that the system is capable to detect 417 gr of HMX explosive material (158 gr nitrogen) by 10 minutes of counting time. To modify the system and to decrease the detection limits some opinions are given

  12. Prompt Fission Neutron Experiments on 235U(n,f) and 252Cf(SF)

    Science.gov (United States)

    Göök, A.; Hambsch, F.-J.; Oberstedt, S.; Vidali, M.

    For nuclear modeling and improved evaluation of nuclear data knowledge about fluctuations of the prompt neutron multiplicity as a function of incident neutron energy is requested for the major actinides 235U and 239Pu. Experimental investigations of the prompt fission neutron emission in resonance neutron induced fission on 235U are taking place at the GELINA facility of the IRMM. The experiment employs an array of neutron scintillation-detectors (SCINTIA) in conjunction with a newly designed 3D position sensitive twin Frisch-grid ionization chamber. A preparatory experiment on prompt fission neutron emission in 252Cf(SF) was undertaken to verify analysis procedures relevant for the implementation of the SCINTIA neutron detector array. The available literature data on the TKE dependence of the multiplicity show strong deviations. Therefore, effort was focused on investigating experimental factors in low efficiency neutron counting experiments that may lead to faulty determination of this dependence. Taking these factors into account a result that agree well with data from high efficiency neutron counting experiments is obtained.

  13. Numbers of prompt neutrons per fission for U233, U235, Pu239, and Cf252

    International Nuclear Information System (INIS)

    An absolute measurement of #-v#, the average number of prompt neutrons emitted per fission, is being made for the spontaneous fission of Cf262. The relative values of #-v# are being measured for neutron-induced fission of U233, U235, and Pu239, and are being compared with the spontaneous fission #-v# of Cf252. Neutrons with energies between thermal and 15 MeV are used. Particular emphasis is put on studying the dependence of #-v# on the incident neutron energy. A fission counter containing the appropriate isotope is placed in the centre of a large cadmium-loade d liquid scintillator. Through the fissionable isotope is passed a collimated beam of neutrons. Fission events, identified by pulses from the fission counter, open an electronic gate between the large liquid scintillator and a scaler. Scintillator pulses due to capture in the scintillating solution of thermalized fission neutrons are counted during the gate. The fission neutrons are detected almost independently of energy and with very high efficiency. With this technique values of #-v# to an accuracy of 1 % are expected. (author)

  14. Scission-point configurations in ternary fission of 252Cf from trajectory calculations

    International Nuclear Information System (INIS)

    Trajectory calculations have been carried out in a three-point- charge model for the case of spontaneous ternary fission of 252Cf with a view to obtain the initial parameters characterizing the scission configuration. Without any a priori assumptions regarding the distribution of the points of emission of the α particle and the fragment velocity at the time of scission, the values of the initial parameters were obtained by fitting the observed energy distributions by making use of the method of multivariate analysis. It was found that there exist two points of α particle emission, nearer to either of the two fragments and off the axis joining the fragment centers, which reproduce the experijmental distributions equally well. This result does not support the often made assumption that the point of α particle emission coincides with the potential energy minimum on the line joining the fragment centers. With the initial parameters thus obtained, an inverse Monte Carlo calculation was carried out to obtain various correlations between the final values of the energy and the angle of emission of the α particle and the fission fragment kinetic energy. The calculated results agree well with the experiments. The implication of present results on the emission mechanism of the α particle in ternary fission is discussed

  15. Nuclear Structure Studies of Some Neutron Rich Nuclei Produced in 252Cf Spontaneous Fission

    International Nuclear Information System (INIS)

    High spin states of neutron-rich nuclei such as 133,134Te, 93Sr, 105Nb have been studied by measuring γ- γ- γ coincidences (cube), γ- γ- γ- γ coincidences (hypercube) and angular correlations from the spontaneous fission of 252Cf with the LBNL Gammasphere detector array. Four types of particle-hole bands built on the known 334.3 keV isomer in 133Te were identified. The level structure of 93Sr is interpreted, in part, as arising from the weak coupling of the 1d5/2 neutron hole to the yrast states of the 94Sr core. The g-factor of the 4+ state in 134Te was measured, for the first time, by using a new technique developed for measuring angular correlations with Gammasphere. A new level scheme of 105Nb was established. Three new collective bands were identified with a total of 14 new levels and 36 new γ transitions. In 117-122Cd, a shift to more slightly deformed structures was found where the excited levels do not fit the long held picture of one, two and three phonon bands

  16. Applicability of parallel plate avalanche counters to spontaneous fission from 252Cf

    International Nuclear Information System (INIS)

    The construction and performance of the parallel plate avalanche counters (PPACs) using a spontaneous fission source 252Cf is described in this paper. The parallel plate circular electrodes are made of aluminum foils having a thickness less than ten microns. After fabrication, the detectors and the source are mounted inside a reaction chamber, the source between the two detectors. A low pressure is created inside the chamber using isobutane (C4H10) and a high voltage is applied to the electrodes. The detectors are first operated at different pressures and voltages to find the optimum values of the pressure and the voltage. This is necessary to avoid the sparking threshold, to achieve a good time resolution and to keep the gain of the detectors high and constant. The PPACs are operated in 2π- and 4π-geometries. In 4π-geometry the detectors are allowed to function in coincidence and noncoincidence mode. The resulting pulse height and the time spectra are studied using the computer code ROOT and some conclusions are drawn from these analyses. The pulse height spectrum shows a clear separation between the fission fragments and the alpha particles and the time spectrum indicates a good intrinsic time resolution, 0.76 ns. (author)

  17. Nuclear isomerism in fission fragments produced by the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    This thesis is devoted to the study of the nuclear structure of neutron-rich nuclei, via the search of isomeric nuclear states. Neutron-rich nuclei were produced in the spontaneous fission of 252Cf. The experimental study of isomeric states in these nuclei was performed with the γ-array EUROGAM II, coupled to an additional and original fission fragment detector composed by photovoltaic cells, SAPhIR. The photovoltaic cells are well adapted to detect low energy heavy ions and have good energy and time resolutions to obtain a good fission fragment detection. This experiment led to the discovery of new isomeric states in 135Xe, 104Mo, 146,147,148Ce and 152,154,156Nd, with lifetimes between 60 ns and 2 μs. Level schemes of these nuclei have been completed. An interpretation of the isomeric states in the nuclei 154,156Nd and 156,158Sm was performed by Hartree-Fock-Bogolyubov calculations using the DIS Gogny force with two quasi-particles excitations. The confrontation with the experimental results led to an interpretation of these isomeric states as K-isomers. (author)

  18. Kinetic energies of cluster fragments in ternary fission of 252 Cf

    Science.gov (United States)

    Vijayaraghavan, K. R.; von Oertzen, W.; Balasubramaniam, M.

    2012-03-01

    The kinetic energy distribution and potential energies of fragments from the collinear cluster tripartition (CCT), the "true" ternary fission of 252Cf, have been calculated. It is assumed that the breakup of the nucleus into three fragments happens sequentially in two steps from a hyper-deformed shape. In the first step a first neck rupture occurs of the parent radioactive nucleus, forming two fragments (one of them is usually 132Sn) and, in the second step, one of the two fragments breaks into two other fragments, resulting finally in three fragments (the experiment is based on a binary coincidence where a missing mass is determined). We show the result for the principal combination of the three spherical fragments (semi-magic isotopes of Sn, Ca, Ni) observed recently experimentally. These isotopes are clusters with high Q -values, which produce the highest yields in the ternary fission bump. It is shown that the kinetic energies of the middle fragments have very low values, making their experimental detection quite difficult. This fact explains why the direct detection of true ternary fission with three fragments heavier than A > 40 has escaped experimental observation.

  19. Improved calculation of the prompt fission neutron spectrum from the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    An improved calculation is presented for the prompt fission neutron spectrum N(E) from the spontaneous fission of 252Cf. In this calculation the fission-spectrum model of Madland and Nix is used, but with several improvements leading to a physically more accurate representation of the spectrum. Specifically, the contributions to N(E) from the entire fission-fragment mass and charge distributions will be calculated instead of calculating on the basis of a seven-point approximation to the peaks of these distributions as has been done in the past. Therefore, values of the energy release in fission, fission-fragment kinetic energy, nuclear level density, and compound nucleus cross section for the inverse process will be considered on a point-by-point basis over the fragment yield distributions instead of considering averages of these quantities over the peaks of the distributions. Particular attention will be given to the energy-dependent compound nucleus cross sections and to the nuclear level density model. Other refinements to the calculation of N(E) will also be discussed. Results will be presented and compared with earlier calculations of the spectrum and with recent experimental measurements of the spectrum. 9 figs

  20. Measurements of gamma-ray dose from a moderated 252Cf source

    International Nuclear Information System (INIS)

    The gamma-ray dose fraction from a moderated 252Cf source was determined by using three types of dosimetry systems. Measurements were carried out in air at a distance of 35 cm from the surface of the moderating sphere (50 cm from the source which is at the center of the sphere) to the geometrical center of each detector. The moderating sphere is 0.8-mm-thick stainless steel shell filled with D2O and covered with 0.5 mm of cadmium. Measurements were also carried out with instruments and dosimeters positioned at the surface of a 40 cm x 40 cm x 15 cm plexiglass irradiation phantom whose front surface was also 35 cm from the surface of the moderating sphere. A-150 tissue-equivalent (TE) plastic ionization chambers and a TE proportional counter (TEPC) were used to measure tissue dose, from which the neutron dose equivalent was computed. The ratio of gamma-ray dose to the neutron dose equivalent was determined by using a relatively neutron-insensitive Geiger-Mueller (GM) counter and thermoluminescent dosimeters (TLD). In addition, the event-size spectrum measured by the TEPC was also used to compute the gamma-ray dose fraction. The average value for the ratio of gamma-ray dose to neutron dose equivalent was found to be 0.18 with an uncertainty of about +-18%

  1. Regional heat loss in resting man during immersion in 25.2 degrees C water.

    Science.gov (United States)

    Wade, C E; Dacanay, S; Smith, R M

    1979-06-01

    Five male subjects having a wide range of relative body fat, 9.2-20.2%, were studied during total body immersion in water at 25.2 degrees C. The regional surface area of each subject was calculated from anthropometric data utilizing a segmental geometric model. Skin temperatures (Tsk) and regional skin heat loss were measured prior to and during 30 min immersion at 13 sites. During immersion, mean Tsk was 25.9 degrees C and remained significantly higher than the water temperature. A measurable temperature gradient for heat flow was observed from all body segments. Segimental temperature in water ranged from 26.7-25.4 degrees C, being warmest at the neck and coolest at the foot. Heat the flow per regional area was highest in the neck, 187 W/m2, and least at the foot, 12 W/m2. Heat flow from each body region was dependent on regional Tsk. Skinfold thickness was a minor factor in altering regional heat flow in the foot, hand, lower arm, upper arm, thigh, and calf; in the torso, neck, and head regions it was of major importance in detering heat loss. PMID:475707

  2. Two-phase flow measurements with 252Cf: Design aspects and considerations

    International Nuclear Information System (INIS)

    For many years 252Cf has been used for measuring moisture content, particularly in the ground's soil, by detecting the amount of slowing down (thermalization) of the source's fission neutrons by the hydrogen nuclei in water. The same concept has been employed for measuring the phase volume fraction in two-phase flows. Although two-phase boiling water measurements are in principle similar to those relating to moisture content, they present different challenges. Unlike the extended, stable, and reasonably uniform medium of the ground, two-phase flow measurements are conducted for a limited amount of fluid enclosed within a duct with metallic or polymer walls, and the phenomenon evolves with time, often rapidly, as phase transformation occurs in a heterogeneous fashion. These aspects demand special attention to design details. Although the principle of using neutron slowing down to measure hydrogen content is basic and straightforward, its application in a confined and evolving medium such as two-phase flow can be challenging. This paper identifies some of these challenges and presents some approaches for dealing with them

  3. Neutron and photon dosimetry at an installed high emission 252Cf source

    International Nuclear Information System (INIS)

    The irradiation hazard was studied in work with the 252Cf fission spectrum neutron source (with a total amount of 1 mg) with a total neutron emission of 2.3x109 s-1. Gamma radiation and neutrons were measured using film dosemeters and track detectors in association with fissionable material (U enriched to 6.5% of 235U and an alloy of Th + 0.5% of natural U). Radiation doses and dose equivalents were assessed by methods developed at the UVVVR Personnel Dosimetry Laboratory. Relations were determined of fast and slow neutrons, this with shielding the staircase with moulded NEUTROSTOP 3B bricks and with the staircase unshielded. It was found that in the control room the dose equivalent did not exceed 1.5x105 Sv.h-1, i.e., 1.5 mrem/h. With the staircase shielded the dose equivalent decreased by about 1/3. Delayed neutron fluence only increased near the shielding; their low biological efficiency, however, does not affect the total dose and dose equivalent values. Also studied were changes in spectra and the respective spectral part proportions. It was found that the slow neutron contribution increased with distance and the presence of a moderating medium up to the equilibrium state when only an even decrease started of the dosimetric values of all spectral components. (B.S.)

  4. Decoupling of uranium metal with borated plaster using 252Cf nose analysis methods

    International Nuclear Information System (INIS)

    The use of borated plaster to isolate uranium (93.2 wt % 235U) metal was studied in a series of subcritical experiments with uranium metal cylinders (7.0 in. diam, 2.0 in. thick) and slabs (approx.1.4 x approx.5.4 x approx.10.1 in. dimensions). In the cylindrical experiments, the thickness of borated plaster was varied up to 10 in. and the subcriticality measured using the 252Cf-source-driven neutron noise analysis method. In the experiments with the uranium slabs, an array of slabs 3 wide and 8 high was assembled in steps to demonstrate the subcriticality of this array with 3.75-in.-thick borated plaster as an isolating material between all uranium slabs. In the slab experiments, both noise analysis and source neutron multiplication measurements were performed. Before assembly of the slab array the presence of boron in the plaster was verified by neutron transmission and gamma-ray spectrometry measurements

  5. Comparative dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for brain tumors

    OpenAIRE

    Samia de Freitas Brandao; Tarcisio Passos Ribeiro de Campos

    2013-01-01

    Objective Comparative analysis of dosimetry in intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT for treatment of brain tumors. Materials and Methods Simulations of intracavitary balloon catheter brachytherapy with I-125 and in Cf-252 brachytherapy combined with BNCT were performed with the MCNP5 code, modeling the treatment of a brain tumor on a voxel computational phantom representing a human head. Absorbed dose rates were converted int...

  6. New source moderator geometry to improve performance of 252Cf and 241Am Be source-based PGNAA setups

    Science.gov (United States)

    Naqvi, A. A.; Abdelmonem, M. S.; Al-Misned, Ghada; Al-Ghamdi, Hanan

    2006-06-01

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups.

  7. Effects of scattered neutrons on the neutron radiation field generated by Cf-252 neutron source with a shield

    International Nuclear Information System (INIS)

    Background: Shields are commonly constructed for a radionuclide neutron source m an actual calibration room in practice. Purpose: Monte Carlo (MC) calculation and experiments were applied to evaluate the effects of scattered neutrons on the neutron radiation field generated by Cf-252 neutron source with a shield. Methods: The effects of scattered neutrons caused by the shield of Cf-252 neutron source were evaluated by calculating the neutron spectra, neutron flux rate and neutron ambient dose equivalent with MC simulation. Similarly, the effects of scattered neutrons caused by the walls, ground and roof of source room were analyzed. Results: The calculation results show that the neutron flux-ambient dose equivalent conversion factor changes from 385 pSv·cm2 of a bare Cf-252 radionuclide from an idealized situation to 280 pSv·cm2 with the shield. The contribution of scattered neutrons from the walls, ground and roof is proportional to the square of distance between wall and source. The experimental data on dose rate are consistent with the calculated results and indicate the reliability of this method. Conclusion: This study provides a practical and feasible way to calibrate the radiation protection instruments using a non-standard radionuclide neutron radiation field. (authors)

  8. Accelerator target

    Energy Technology Data Exchange (ETDEWEB)

    Schlyer, David J. (Bellport, NY); Ferrieri, Richard A. (Patchogue, NY); Koehler, Conrad (Miller Place, NY)

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  9. Study of the isomer nuclei produced in the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    Isomeric states have been studied in fission fragments produced by spontaneous fission of 252Cf. 34 isomeric nuclei have been identified by using coincidences between γ-rays detected in EUROGAM II and fission fragments detected in photovoltaic cells. Lifetimes from 20 ns up to 2 μs have been measured. Microscopic interpretation of the isomeric levels discovered has been tried by means of the Hartree-Fock-Bogolyubov procedure using Gogny force. It was found that the 152,154,156Nd nuclei have prolate deformation in their ground state; the rotational band built on this ground state is well reproduced by the calculation. For these nuclei the 2 quasi-particle excited states energies are above 1 MeV in agreement with the experiment. The computation confirms the similitude of the 156Nd and 158Sm isomeric states associated to neutron 2 quasi-particles of Jπ Kπ = 5- (ν 5/2 (642) x ν 5/2 (523)) while such similitude does not occur for the isotone nuclei 154Nd and 156Sm. The computation predicts a proton 2 quasi-particle excited states of Jπ = 5-, near the isomeric level measured in 156Sm but not for that of 154Nd. Concerning the 152Nd the calculated level density is very near that of the states measured in the 1.6 to 2.3 MeV interval. However, the lack of precise information on spins and parities of the measured levels does make not possible a confrontation with the calculations. An up-graded equipment implying 32 photovoltaic cells instead of 2 cells is to be developed and installed by the EUROGAM

  10. Biodegradation of MC252 oil in oil:sand aggregates in a coastal headland beach environment

    Directory of Open Access Journals (Sweden)

    Vijaikrishnah eElango

    2014-04-01

    Full Text Available Biodegradation potential of MC252 in oil:sand aggregates, termed surface residue balls (SRBs, was examined using multiple lines of evidence on a heavily-impacted coastal headland beach in Louisiana, USA. SRBs were sampled over a 16-month period on the supratidal beach environment where reasonable control existed on the residence time of the aggregates on the beach surface. PAH and alkane concentration ratios were measured including PAH/C30-hopane, C2/C3 phenanthrenes, C2/C3 dibenzothiophenes and alkane/C30-hopane and demonstrated unequivocally that biodegradation was occurring in SRBs in the supratidal. These biodegradation reactions occurred over time frames relevant to the coastal processes moving SRBs off the beach. In contrast, submerged oil mat (SOM samples did not demonstrate chemical changes consistent with biodegradation. Review and analysis of additional biogeochemical parameters suggested the existence of a moisture and N-limited biodegradation regime on the supratidal beach environment. At this location, SRBs possess moisture contents < 2% and molar C:N ratios from 131-323, well outside of optimal values for biodegradation in the literature. Despite these limitations, biodegradation of PAHs and alkanes proceeded at relevant rates (2-8 year-1 due in part to the presence of degrading populations, i.e., Mycobacterium sp., adapted to these conditions. For SOM samples in the intertidal, an oxygen and salinity-impacted regime is proposed that severely limits biodegradation of alkanes and PAHs in this environment. These results support the hypothesis that SRBs deposited at different locations on the beach have different biogeochemical characteristics (e.g., moisture; salinity; terminal electron acceptors; nutrient; and oil composition due, in part, to their location on the landscape.

  11. Level structures of 110,111,112,113Rh from measurements on 252Cf

    International Nuclear Information System (INIS)

    Level schemes of 111Rh and 113Rh are proposed from the analysis of γ-γ-γ coincidence data from a 252Cf spontaneous fission source with Gammasphere. These schemes have the highest excitation energies and spins yet established in these nuclei, as well as weakly populated bands not reported in earlier fission- γ work. From these data, information on shapes is inferred. By analogy with lighter Z=45 odd-even isotopes, tentative spins and parities are assigned to members of several rotational bands. In this region triaxial nuclear shapes are known to occur, and we carried out calculations for 111Rh and 113Rh with the triaxial-rotor-plus-particle model. The 7/2+πg9/2 bands of both nuclei, as well as lighter isotopes studied by others, show similar signature splitting. Our model calculations give a reasonable fit to the signature splitting, collective sidebands, and transition probabilities at near-maximum triaxiality with γ≅28 deg. For the K=1/2+[431] band, experiment and model calculations do not fit well, which is accounted for by greater prolate deformation of the K=1/2+ band, a case of shape coexistence. Our data on 110,112Rh show no backbending and thus support the idea of the band crossing in the ground band of the odd-A neighbors being due to alignment of an h11/2 neutron pair. In 111,113Rh above the band crossing (spins ≅21/2(ℎ/2π)) the ground band appears to split, with two similar branches. We consider the possibility that chiral doubling may be involved, but there are not enough levels to determine that

  12. About the first experiment on investigation of 129I, 237Np, 238Pu and 239Pu transmutation at the nuclotron 2.52 GeV deuteron beam in neutron field generated in U/Pb-assembly 'Energy plus transmutation'

    International Nuclear Information System (INIS)

    Preliminary results of the first experiment with energy 2.52 GeV at the electronuclear setup which consists of Pb-target (diameter 8.4 cm, length 45.6 cm) and natU-blanket (206.4 kg), transmutation samples of 129I, 237Np, 238Pu and 239Pu (radioecological aspect) are described. Hermetically sealed samples in notable amounts are gathered in atomic reactors and setups of industries which use nuclear materials and nuclear technologies were irradiated in the field of neutrons produced in the Pb-target and propagated in the natU-blanket. Estimates of transmutations were obtained as a result of measurements of gamma activities of the samples. The information about the space and energy distribution of neutrons in the volume of the lead target and the uranium blanket was obtained with the help of sets of activation threshold detectors (Al, Co, Y, I, Au, Bi and others), solid-state nuclear track detectors, 3He neutron detectors and nuclear emulsion. Comparison of the experimental data with the results of simulation with the MCNPX program was performed

  13. The legacy of Cf-252 operations at Savannah River Technology Center: Continuous releases of radioiodine to the atmosphere

    International Nuclear Information System (INIS)

    The iodine isotopes I-132, 1-133, I-134, and I-135, which have half-lives ranging from 53 minutes to 21 hours, are measured in the atmospheric effluent from the Savannah River Technology Center (SRTC) at the Savannah River Site (SRS) near Aiken, South Carolina. SRS is operated by Westinghouse Savannah River Company for the US Department of Energy (DOE). The isotopes' release rates range from 10 to 300 microcuries per week compared to the rate. The resulting annual dose from all iodine isotopes is minor; it comprises 0.01 percent of the total offsite dose due to atmospheric releases from SRS in 1990. Circumstantial evidence indicates the radioiodine originates from traces of unencapsulated Cf-252. The determination that spontaneous fission of Cf-252 is the source of the radioiodine has several ramifications. Radioactive fission-product isotopes of the noble gas elements krypton and xenon must also be released. Noble gases are more volatile and mobile than iodine. Also, the released iodine isotopes decay to xenon isotopes. The noble gases decay to non-gaseous elements that are transported along with radioiodine to the terrestrial environment by deposition from the SRTC plume. Only Sr-89 is believed to accumulate sufficiently in the environment to approach detectable levels. Given similar conditions in earlier years, releases of short-lived radioiodine have occurred undetected in routine monitoring since the early 1970s. Release rates 20 years ago would have been 200 times greater than current release rates. This report documents preliminary experiments conducted by SRTC and Environmental Monitoring Section (EMS) scientists. The release process and the environmental impact of fission products from Cf-252 should be thoroughly researched

  14. Association between TNF promoter -308 G>A and LTA 252 A>G polymorphisms and systemic lupus erythematosus.

    Science.gov (United States)

    Ahmed, Hanan Hosni; Taha, Fatma Mohamed; Darweesh, Hanan El-Sayed; Morsi, Heba Mohamed Abdelhafiz

    2014-01-01

    Tumor necrosis factor (TNF) and lymphotoxin alpha (LTA) are pivotal cytokines in the pathogenesis of systemic lupus erythematosus (SLE). To investigate the possible association of the polymorphism of the TNF promoter gene -308 and that of the LTA gene 252 with susceptibility to SLE and with phenotypic disease features in Egyptian patients. A case control study involving 100 SLE patients and 100 unrelated healthy controls. Polymerase chain reaction and restriction fragment length polymorphism methods were applied to detect genetic polymorphism. We found that TNF-308 genotype AA was significantly increase by 26 % in SLE patients compared to 10 % in the control group (p = 0.003; OR 3.16; CI 1.43-6.98) and the frequency of the A allele of the TNF promoter -308 was significantly higher in the SLE patients (42 %) than in the control subjects (24 %) (p < 0.001; OR 2.29; 95 % CI 1.49-3.52). Genotype LTA 252 GG showed a significant increase by 22 % in SLE patients compared to 6 % in the control group (p = 0.001; OR 4.42; 95 % CI 1.71-11.44), and the frequency of the G allele of the LTA was significantly higher in the SLE patients (38 %) than in the control subjects (21 %) (p < 0.001; OR 2.31; 95 % CI 1.48-3.6). Genotype (AA+GA) of TNF was significantly associated with clinical manifestations as malar rash, arthritis, oral ulcers, serositis and systemic lupus erythematosus disease activity index. Genotype (GG+GA) of LTA was significantly associated with arthritis. These results suggest that TNF and LTA genetic polymorphisms contribute to SLE susceptibility in the Egyptian population and are associated with disease characteristics. TNF-308 and LTA+252 polymorphic markers may be used for early diagnosis of SLE and early prediction of clinical manifestations, like arthritis. PMID:24420856

  15. Beam-Port Design of a Radiobiological Dosimetry Experiment for 10B-Enhanced 252Cf Brachytherapy

    International Nuclear Information System (INIS)

    It has been previously suggested that the incorporation of 10B-labeled drugs into tumor cells might significantly increase the dose to the peripheral tumor cells in 252Cf brachytherapy. The dose enhancement comes from the thermal neutron capture reactions of 10B(n, α)7Li. As a new cancer treatment modality, this so-called 10und B-und Enhanced 252und Cf und Brachyund therapy (BECBT) is currently being commercialized by Isotron. One of the challenges for implementing BECBT has been to determine the maximum tolerable dose (MTD) to the normal tissue surrounding a tumor. Because the relative biological effectiveness for the 10B(n, α)7Li reaction products is greater than that for fission neutrons, the MTD should decrease as 10B concentration increases for BECBT. To more precisely determine the MTD for BECBT, we intend to conduct both in vitro (cell culture) and in vivo (rat) experiments with a 50-mg 252Cf source. We will use cell survival fraction and normal brain necrosis as the biological end points for the cell-culture experiments and rat experiments, respectively. To carry out these experiments, the neutron field to which the samples are exposed must contain a significant portion of thermal neutrons. The rat experiments further require the use of a very small and well-collimated neutron beam to effectively irradiate the rat brain while minimizing the dose to its whole body. This paper discusses the design criteria for the experimental neutron beam port and the computational work leading to its optimal configuration

  16. The emission probabilities of long range alpha particles from even-even 244-252Cm isotopes

    OpenAIRE

    Santhosh, K P; Krishnan, Sreejith; Priyanka, B.

    2014-01-01

    The alpha accompanied cold ternary fission of even-even 244Cm, 246Cm, 248Cm, 250Cm and 252Cm isotopes have been studied by taking the interacting barrier as the sum of Coulomb and proximity potential with the fragments in equatorial configuration. The favorable fragment combinations are obtained from the cold reaction valley plot and by calculating the relative yield for the charge minimized fragments. In the alpha accompanied ternary fission of 244Cm isotope, the highest yield is found for t...

  17. Detection of ternary fission fragments from 252Cf with a position-sensitive ΔE-E telescope

    International Nuclear Information System (INIS)

    Using a thin silicon diode detector with thickness of 12 μm coupled with a Timepix detector (equipped with a 300 μm silicon sensor), a position-sensitive ΔE-E telescope has been constructed. The telescope provides information about position, energy, time and type of registered particles. The emission probabilities and the energy distribution of ternary particles (He, Li, Be) from 252Cf spontaneous fission source were determined using a pair of these telescopes operated in coincidence and with synchronized readout. The response of Timepix detector to different particle species was tested by ternary particles

  18. Design of a 252Cf neutron assay system for evaluation at the Savannah River Plant fuel fabrication facility

    International Nuclear Information System (INIS)

    A nondestructive assay (NDA) unit will be evaluated at the Savannah River Plant (SRP) reactor fuel fabrication facility for measurement of a range of highly enriched uranium materials. The unit employs cyclic neutron interrogation with a Cf-252 neutron source followed by delayed-neutron counting to assay the U-235 content of fuel alloys with up to 2.4 kg U-235 per item in addition to scrap and waste with a lower U-235 content. The accuracy goal for the majority of the measurements is 1 to 3 percent

  19. Replacing a 252Cf source with a neutron generator in a shuffler - a conceptual design performed with MCNPX

    Energy Technology Data Exchange (ETDEWEB)

    Schear, Melissa A [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory

    2009-01-01

    The {sup 252}Cf shuffler has been widely used in nuclear safeguards and radioactive waste management to assay fissile isotopes, such as {sup 235}U or {sup 239}Pu, present in a variety of samples, ranging from small cans of uranium waste to metal samples weighing several kilograms. Like other non-destructive assay instruments, the shuffler uses an interrogating neutron source to induce fissions in the sample. Although shufflers with {sup 252}Cf sources have been reliably used for several decades, replacing this isotopic source with a neutron generator presents some distinct advantages. Neutron generators can be run in a continuous or pulsed mode, and may be turned off, eliminating the need for shielding and a shuffling mechanism in the shuffler. There is also essentially no dose to personnel during installation, and no reliance on the availability of {sup 252}Cf. Despite these advantages, the more energetic neutrons emitted from the neutron generator (141 MeV for D-T generators) present some challenges for certain material types. For example when the enrichment of a uranium sample is unknown, the fission of {sup 238}U is generally undesirable. Since measuring uranium is one of the main uses of a shuffler, reducing the delayed neutron contribution from {sup 238}U is desirable. Hence, the shuffler hardware must be modified to accommodate a moderator configuration near the source to tailor the interrogating spectrum in a manner which promotes sub-threshold fissions (below 1 MeV) but avoids the over-moderation of the interrogating neutrons so as to avoid self-shielding. In this study, where there are many material and geometry combinations, the Monte Carlo N-Particle eXtended (MCNPX) transport code was used to model, design, and optimize the moderator configuration within the shuffler geometry. The code is then used to evaluate and compare the assay performances of both the modified shuffler and the current {sup 252}Cf shuffler designs for different test samples. The

  20. Neutron monitor calibration with 241AmBe(α, n), 252Cf , 252Cf+D2O and 238PuBe(α, n) used in dose evaluation near Linac

    International Nuclear Information System (INIS)

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, 241AmBe (α, n), 252Cf (f, n) and 252Cf+D2O, and a 238PuBe(α, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (author)

  1. A computational approach to finding novel targets for existing drugs.

    Directory of Open Access Journals (Sweden)

    Yvonne Y Li

    2011-09-01

    Full Text Available Repositioning existing drugs for new therapeutic uses is an efficient approach to drug discovery. We have developed a computational drug repositioning pipeline to perform large-scale molecular docking of small molecule drugs against protein drug targets, in order to map the drug-target interaction space and find novel interactions. Our method emphasizes removing false positive interaction predictions using criteria from known interaction docking, consensus scoring, and specificity. In all, our database contains 252 human protein drug targets that we classify as reliable-for-docking as well as 4621 approved and experimental small molecule drugs from DrugBank. These were cross-docked, then filtered through stringent scoring criteria to select top drug-target interactions. In particular, we used MAPK14 and the kinase inhibitor BIM-8 as examples where our stringent thresholds enriched the predicted drug-target interactions with known interactions up to 20 times compared to standard score thresholds. We validated nilotinib as a potent MAPK14 inhibitor in vitro (IC50 40 nM, suggesting a potential use for this drug in treating inflammatory diseases. The published literature indicated experimental evidence for 31 of the top predicted interactions, highlighting the promising nature of our approach. Novel interactions discovered may lead to the drug being repositioned as a therapeutic treatment for its off-target's associated disease, added insight into the drug's mechanism of action, and added insight into the drug's side effects.

  2. Measurement of the neutron activity of a 252Cf source relative to the average number of prompt neutrons emitted per fission for the spontaneous fission

    International Nuclear Information System (INIS)

    A method was developed for measuring the absolute neutron activity of a large 252Cf source. The neutron counting assembly is composed of eight BF3 counters mounted in a large tank filled with water which is used as a moderator. The detection efficiency is determined using a low activity 252Cf source. The method is based on the identification of every fission event, followed by the counting of the fission neutrons detected by the BF3 counters during a time interval equal to the maximum neutron lifetime in the moderator. The efficiency is thus obtained relative to the average number of prompt neutrons emitted per 252Cf spontaneous fission which is commonly used as a standard. The measurement accuracy is estimated to be of the order of 1%

  3. SSNTD study of the probable influence of alpha activity on the mass distribution of 252Cf fission fragments

    International Nuclear Information System (INIS)

    The SSNTD has come a long way in its application for the study of nuclear phenomena. Spontaneous fission of transuranic elements is one such phenomena wherein use of SSNTD offers easy registration of the signature of the fission fragments. The object of the present study is to explore whether any one of the track parameters such as the diameter can be used to estimate the atomic mass ratios of the spontaneous fission fragments. The spontaneous fission data from 252Cf recorded almost at the end of one and four half-life periods for alpha decay are analysed, taking a plot of the number of tracks versus the track diameter. From these plots it is seen that initially, when significant alpha activity of 252Cf persists, the fission fragments appear to cluster into two predominant groups as indicated by two peaks. The ratio of the diameters at these peak positions appear to be related to the ratio of average mass numbers of the light and heavy groups of fission fragments. However, absence of two peaks for similar plots at the end of about four half-life periods for alpha decay suggests that presumably the presence of alphas influence the mass distribution of the fission fragments

  4. A comparison of {sup 252}Cf and 14-MeV neutron excitation to identify chemical warfare agents by PGNAA

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, A.J.; Harlow, B.D.; Edwards, A.J.; Krebs, K.M.; Jones, J.L.; Yoon, W.; Zabriskie, J.M.; Dougan, A.D.

    2000-07-01

    Since 1992, Idaho National Engineering and Environmental Laboratory's portable isotopic neutron spectrometry (PINS) system has been widely used for the nondestructive assessment of munitions suspected to contain chemical warfare agents, such as the nerve agent sarin. PINS is a {sup 252}Cf-based prompt gamma-ray neutron activation analysis (PGNAA) system. The standard PINS system employs a partially moderated 5-{micro}g {sup 252}Cf source emitting 10{sup 7} n/s to excite the atomic nuclei inside the item under test. The chemical elements inside the item are revealed by their characteristic gamma-ray spectrum, measured by a high-resolution high-purity germanium gamma-ray spectrometer. The system computer then infers the fill compound or mixture from the elemental data extracted from the gamma-ray spectrum. Reliable PINS assessments can be completed in as little as 100 s for favorable cases such as white phosphorus smoke munitions, but normally, a 1000 to 3000 live-second counting interval is required. To improve PINS throughput when hundreds or more munitions must be assessed, they are evaluating the possible advantages of 14-MeV neutron excitation over their current radioisotopic source.

  5. Multi-modal fission in collinear ternary cluster decay of {sup 252}Cf(sf, fff)

    Energy Technology Data Exchange (ETDEWEB)

    Oertzen, W. von, E-mail: oertzen@helmholtz-berlin.de [Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Joint Institute for Nuclear Research, FLNR, 141980 Dubna (Russian Federation); Nasirov, A.K. [Joint Institute for Nuclear Research, FLNR, 141980 Dubna (Russian Federation); Institute of Nuclear Physics, 100214, Tashkent (Uzbekistan); Kyungpook National University, 702-701, Daegu (Korea, Republic of); Tashkhodjaev, R.B. [Institute of Nuclear Physics, 100214, Tashkent (Uzbekistan); Inha University in Tashkent, 100170, Tashkent (Uzbekistan)

    2015-06-30

    We discuss the multiple decay modes of collinear fission in {sup 252}Cf(sf, fff), with three fragments as suggested by the potential energy surface (PES). Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of {sup 252}Cf(sf) into three different masses (e.g. {sup 132–140}Sn, {sup 52–48}Ca, {sup 68–72}Ni), observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions) of the JINR (Dubna) the collinear cluster tripartition (CCT), is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay.

  6. The emission probabilities of long range alpha particles from even-even 244-252Cm isotopes

    CERN Document Server

    Santhosh, K P; Priyanka, B

    2014-01-01

    The alpha accompanied cold ternary fission of even-even 244Cm, 246Cm, 248Cm, 250Cm and 252Cm isotopes have been studied by taking the interacting barrier as the sum of Coulomb and proximity potential with the fragments in equatorial configuration. The favorable fragment combinations are obtained from the cold reaction valley plot and by calculating the relative yield for the charge minimized fragments. In the alpha accompanied ternary fission of 244Cm isotope, the highest yield is found for the fragment combination 110Ru+4He+130Sn, which possess near doubly magic nuclei 130Sn. For the ternary fission of 246Cm, 248Cm, 250Cm and 252Cm isotopes with 4He as light charged particle, the highest yield is obtained for the fragment combination with doubly magic nuclei 132Sn as the heavier fragment. The emission probabilities and kinetic energies of long range alpha particle have been computed for the 242,244,246,248Cm isotopes and are found to be in good agreement with the experimental data. The relative yields for th...

  7. Identification of new neutron-rich rare-earth nuclei produced in /sup 252/Cf spontaneous fission

    CERN Document Server

    Greenwood, R C; Gehrke, R J; Meikrantz, D H

    1981-01-01

    A program of systematic study of the decay properties of neutron-rich rare-earth nuclei with 30 s252/Cf spontaneous fission, is currently underway using the Idaho ESOL (Elemental Separation On Line) Facility. The chemistry system used for the rare-earth elemental separations consists of two high-performance chromatography columns connected in series and coupled to the /sup 252 /Cf fission source via a helium gas-jet transport arrangement. The time delay for separation and initiation of gamma -ray counting with results which have been obtained to date with this system include the identification of a number of new neutron-rich rare-earth isotopes including /sup 155/Pm (t/sub 1/2/=48+or-4 s) and /sup 163/Gd (t/sub 1 /2/=68+or-3 s), in addition to 5.51 min /sup 158/Sm which was identified in an earlier series of experiments. (11 refs).

  8. Study the Possibility of measuring Heavy Metals Arising from Gold Mining Sample using 252Cf Neutron Source

    International Nuclear Information System (INIS)

    Mining activities contribute immensely to trace element pollution .The present work studied the possibility of measuring heavy metals arising from gold mining areas Eastern Desert in Egypt using the isotopic 252Cf neutron source. 38.5 g of the sample is irradiated in a neutron field of 252Cf for 36.75 days and 0.3 mg of the sample is irradiated at the Pneumatic Irradiation Rabbit System (PIRS) built in the vertical thermal column of the ET-RR-2 reactor . The induced activities in the samples are measured using two high resolution fray spectrometry systems (including two calibrated HPGe detectors). The kο standardization neutron activation analysis (kο-NAA) method was used to analyze the sample under investigation. Thermal to epithermal flux ratio fat the two irradiation positions are measured. The obtained results indicated that the values of the suspected heavy metals such as sodium, magnesium, potassium, manganese, arsenic, ruthenium and tantalum were higher than the background values, signifying accumulation of these heavy metals due to gold mining activities .The accuracy and precision of the method has been evaluated

  9. 252Cf-source-correlated transmission measurements for uranyl fluoride deposit in a 24-in-OD process pipe

    International Nuclear Information System (INIS)

    Characterization of a hydrated uranyl fluoride (UO2F2·nH2O) deposit in a 17 ft long, 24 in OD process pipe at the former Oak Ridge Gaseous Diffusion Plant was successfully performed using 252Cf-source-correlated time-of-flight (TOF) transmission measurements. These measurements of neutrons and gamma rays through the pipe from an external 252Cf fission source were used to measure the deposit profile and its distribution along the pipe, the hydration (or H/U), and the total uranium mass. The measurements were performed with a source in an ionization chamber on one side of the pipe and detectors on the other. Scanning the pipe vertically and horizontally produced a spatial and time-dependent radiograph of the deposit in which transmitted gamma rays and neutrons were separated in time. The cross-correlation function between the source and the detector was measured with the Nuclear Weapons Identification System. After correcting for pipe effects, the deposit thickness was determined from the transmitted neutrons and H/U from the gamma rays. Results were consistent with a later intrusive observation of the shape and the color of the deposit; i.e., the deposit was annular and was on the top of the pipe at some locations, demonstrating the usefulness of this method for deposit characterization

  10. 252Cf-source-correlated transmission measurements for uranyl fluoride deposit in a 24-in-OD process pipe

    Science.gov (United States)

    Uckan, T.; Wyatt, M. S.; Mihalczo, J. T.; Valentine, T. E.; Mullens, J. A.; Hannon, T. F.

    1999-02-01

    Characterization of a hydrated uranyl fluoride (UO 2F 2· nH 2O) deposit in a 17 ft long, 24 in OD process pipe at the former Oak Ridge Gaseous Diffusion Plant was successfully performed using 252Cf-source-correlated time-of-flight (TOF) transmission measurements. These measurements of neutrons and gamma rays through the pipe from an external 252Cf fission source were used to measure the deposit profile and its distribution along the pipe, the hydration (or H/U), and the total uranium mass. The measurements were performed with a source in an ionization chamber on one side of the pipe and detectors on the other. Scanning the pipe vertically and horizontally produced a spatial and time-dependent radiograph of the deposit in which transmitted gamma rays and neutrons were separated in time. The cross-correlation function between the source and the detector was measured with the Nuclear Weapons Identification System. After correcting for pipe effects, the deposit thickness was determined from the transmitted neutrons and H/U from the gamma rays. Results were consistent with a later intrusive observation of the shape and the color of the deposit; i.e., the deposit was annular and was on the top of the pipe at some locations, demonstrating the usefulness of this method for deposit characterization.

  11. Determination of 114Pd cumulative yield and investigation of the fine-structure at light peak in mass distribution of 252Cf spontaneous fission

    International Nuclear Information System (INIS)

    A rapid radiochemical procedure for Pd separation was developed. It was the first time to use radiochemical techniques to determine 114Pd cumulative yield (2.50 ± 0.14)% in 252Cf spontaneous fission. The cumulative yields of (3.50 ± 0.13)% and (3.70 ± 0.11)% for 112Pd and 113gAg were also obtained. These are in agreement with Skovorodkin's results. The cumulative yields determined show that there is a fine-structure at light peak of mass number A = 113 in the mass distribution of 252Cf spontaneous fission

  12. Survival of leukosis La cells after prolonged exposure to gamma-rays of Co60 and mixed gamma-neutron radiation of Cf252

    International Nuclear Information System (INIS)

    Survival curves of mouse leukosis La cells exposed in vitro to γ-rays of Co60 and γ/neutron radiation of Cf252 are characterized by the following parameters: an average lethal dose (D0) is 199.2 and 67.9 rad (for the neutron component), and the extrapolation number, 5.3 and 3.4, correspondingly. RBE of radiation from Cf252 is a function of the radiation dose, that is as the radiation dose increases the RBE decreases down to a minimum value of 1.7 for mixed irradiation and 2.2 for a purely neutron component

  13. Neutron monitor calibration with {sup 241}AmBe({alpha}, n), {sup 252}Cf , {sup 252C}f+D{sub 2}O and {sup 238}PuBe({alpha}, n) used in dose evaluation near Linac

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla Cristina de Souza; Fonseca, Evaldo Simoes da [Instituto de Radioprotecao e Dosimetria (IRD-CNEN/RJ), Rio de Janeiro, RJ (Brazil). Lab. de Neutrons], e-mail: asalgado@ird.gov.br

    2009-07-01

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, {sup 241}AmBe ({alpha}, n), {sup 252}Cf (f, n) and 252{sup C}f+D{sub 2}O, and a 238{sup P}uBe({alpha}, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (a0011uth.

  14. Genome-wide association analysis of self-reported events in 6135 individuals and 252 827 controls identifies 8 loci associated with thrombosis

    DEFF Research Database (Denmark)

    Hinds, David A; Buil, Alfonso; Ziemek, Daniel;

    2016-01-01

    Thrombotic diseases are among the leading causes of morbidity and mortality in the world. To add insights into the genetic regulation of thrombotic disease, we conducted a genome-wide association study (GWAS) of 6135 self-reported blood clots events and 252 827 controls of European ancestry belon...

  15. Measuring neutron energy spectra of 252Cf and Am-Be source with neutron time-of-flight spectrometer with double scintillators

    International Nuclear Information System (INIS)

    We established a neutron time-of-flight spectrometer with double scintillators. It can be used to measure the energy spectra of neutron sources. It is capable of working at above several hundred keV. We measured the energy spectra of 252Cf and Am-Be neutron sources by using this spectrometer. The results obtained were compared to those in other works

  16. Time-of-flight mass spectrometer with 252Cf surface ionisation coupled with high-pressure liquid chromatography for determining pharmaceutical substances in the blood

    International Nuclear Information System (INIS)

    Cf-252 PDMS is well suited for routine applications and can be combined with HPLC. This combined analytical system can be used for measuring the concentrations of pharmaceutical substances in body fluids on the basis of an internal standard. The results (pharmacokinetics, metabolism) indicate the necessary therapeutical dose and the efficacy of the substance applied. (DG)

  17. Spectrum of neutrons emitted from a thick beryllium target bombarded with 7 MeV deuterons

    International Nuclear Information System (INIS)

    The spectrum of neutrons emitted from a thick beryllium target bombarded with 7 MeV deuterons is measured at 25 reaction angles distributed between 00 and 1580, and over the neutron energy range ≅11.0 MeV. The spectrum is determined relative to the standard 252Cf prompt-fission-neutron-spectrum using fast time-of-flight techniques. The results are presented as angle-energy differential distributions and as relative numerical group cross sections suitable for establishing a reference field for applied studies. 24 refs., 4 figs

  18. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Energy Technology Data Exchange (ETDEWEB)

    Seabury, E.H. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)]. E-mail: Edward.Seabury@inl.gov; Blackburn, B.W. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Chichester, D.L. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Wharton, C.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States); Caffrey, A.J. [Idaho National Laboratory, P.O. Box 1625 Idaho Falls, ID 8341-3840 (United States)

    2007-08-15

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, {gamma}) and (n, n') gamma rays from these elements by each type of neutron source.

  19. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    International Nuclear Information System (INIS)

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n') gamma rays from these elements by each type of neutron source

  20. Comparison of DD, DT and Cf-252 neutron excitation of light and medium mass nuclei for field PGNAA applications

    Science.gov (United States)

    Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.

    2007-08-01

    Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.

  1. Monte Carlo simulation optimisation of zinc sulphide based fast-neutron detector for radiography using a 252Cf source

    Science.gov (United States)

    Meshkian, Mohsen

    2016-02-01

    Neutron radiography is rapidly extending as one of the methods for non-destructive screening of materials. There are various parameters to be studied for optimising imaging screens and image quality for different fast-neutron radiography systems. Herein, a Geant4 Monte Carlo simulation is employed to evaluate the response of a fast-neutron radiography system using a 252Cf neutron source. The neutron radiography system is comprised of a moderator as the neutron-to-proton converter with suspended silver-activated zinc sulphide (ZnS(Ag)) as the phosphor material. The neutron-induced protons deposit energy in the phosphor which consequently emits scintillation light. Further, radiographs are obtained by simulating the overall radiography system including source and sample. Two different standard samples are used to evaluate the quality of the radiographs.

  2. Design of a system for the undersea exploration of manganese nodules by 252Cf neutron induced gamma ray analysis

    International Nuclear Information System (INIS)

    A system for in-situ-analysis of manganese nodules has been designed. It permits the investigation of the concentrations of Ni, Cu and Co in concretions on the deep sea bottom. The surface sediments are collected by a suction system and conveyed into a tank where they are irradiated by neutrons emitted from a 252Cf source. The neutron-capture gamma rays are analyzed by a cooled Ge(Li) detector system. At the same time the bulk density of the nodules is measured by 60Co irradiation and a NaI(Tl) detector. The total device has an analysis cycle of about 15 minutes. It is towed by a ship over the sea bottom. (U.S.)

  3. Magnetic behavior of the oxide spinels: Li0.5Fe2.5-2AlCrO4

    Indian Academy of Sciences (India)

    U N Trivedi; K B Modi; H H Joshi

    2002-05-01

    In order to study the effect of substitution of Fe3+ by Al3+ and Cr3+ in Li0.5Fe2.5O4 on its structural and magnetic properties, the spinel system Li0.5AlCrFe2.5-2O4 ( = 0.0, 0.2, 0.4, 0.5, 0.6 and 0.8) has been characterized by X-ray diffraction, high field magnetization, low field ac susceptibility and 57Fe Mössbauer spectroscopy. Contrary to the earlier reports, about 50% of Al3+ is found to occupy the tetrahedral sites. The system exhibits canted spin structure and a central paramagnetic doublet was found superimposed on magnetic sextet in the Mössbauer spectra ( > 0.5).

  4. Experimental research on specific activity of 24Na using Chinese reference man phantom irradiated by 252Cf neutrons source

    International Nuclear Information System (INIS)

    Objective: To investigate the specific activity of '24Na per unit neutron fluence, AB/Φ,in blood produced for Chinese reference man irradiated by 252Cf neutron source,and to analyze the effects of scattering neutrons from ground,wall,and ceiling in irradiation site on it.Methods: A 252Cf neutron source of 3×108 n/s and the anthropomorphic phantom were used for experiments. The phantom was made from 4 mm thick of outer covering by perspex and the liquid tissue-equivalent substitute in it. The data of phantom dimensions fit into Chinese reference man.The weight ratios of H, N, O and C in substitute equal from source to long axis of phantom were 1.1, 2.1, 3.1 and 4.1 m, respectively. Both the neutron source and the position of xiphisternum of the phantom were 1.6 m above the floor. Results: The average specific activity of 24Na per unit neutron fluence was related to the irradiation-distances, d, and its maximum value, AB/ΦM, deduced by experimental data was about 1.85×10-7 Bq·cm2·g-1. Conclusions: The AB/ΦM corresponds to that of phantom irradiated by plane-parallel beams, and the value is about more 3% than that by BOMAB phantom reported in literature. It has shown that floor-(wall-)scattered neutrons in irradiation site have significant contribution to the specific activity of 24Na, but they contributed relatively little to the induced neutron doses. Consequently,using the specific activity of 24Na for assessing accidental neutron doses received by an individual, the contribution of scattered neutrons in accident site will lead dose to be overestimated, and need to be correct. (authors)

  5. Target Awareness: Lupus

    Science.gov (United States)

    ... Target Awareness: Lupus Jan. 15, 2009 Target Awareness: Lupus Target Awareness: Lupus provides a brief overview of ... Email Print Tags for this Story treatments symptoms Lupus FAQ What is lupus? What are the common ...

  6. Target Awareness: Lupus

    Medline Plus

    Full Text Available ... Target Awareness: Lupus Jan. 15, 2009 Target Awareness: Lupus Target Awareness: Lupus provides a brief overview of ... Email Print Tags for this Story treatments symptoms Lupus FAQ What is lupus? What are the common ...

  7. Target factory in perspective

    International Nuclear Information System (INIS)

    A target factory diagram has been constructed for an analysis of the shell coating process system in relation to target production. The number of deposition units needed to achieve the coating requirements will be a major target production operating cost

  8. Measurement of deeply virtual compton scattering with a polarized-proton target.

    Science.gov (United States)

    Chen, S; Avakian, H; Burkert, V D; Eugenio, P; Adams, G; Amarian, M; Ambrozewicz, P; Anghinolfi, M; Asryan, G; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Batourine, V; Battaglieri, M; Beard, K; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Biselli, A S; Bonner, B E; Bouchigny, S; Boiarinov, S; Bosted, P; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Bültmann, S; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Carnahan, B; Cazes, A; Cole, P L; Collins, P; Coltharp, P; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Crede, V; Cummings, J P; DeMasi, R; DeVita, R; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Deur, A; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Fatemi, R; Fedotov, G; Feldman, G; Feuerbach, R J; Forest, T A; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Gonenc, A; Gothe, R W; Griffioen, K A; Guidal, M; Guillo, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hakobyan, R S; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Huertas, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Joo, K; Juengst, H G; Keith, C; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kubarovsky, V; Kuhn, J; Kuhn, S E; Kuleshov, S V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Li, Ji; Lima, A C S; Livingston, K; Lu, H; Lukashin, K; MacCormick, M; Markov, N; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Morand, L; Morrow, S A; Moteabbed, M; Mueller, J; Mutchler, G S; Nadel-Turonski, P; Napolitano, J; Nasseripour, R; Natasha, N; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Philips, S A; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Popa, I; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabian, Y G; Shaw, J; Shvedunov, N V; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Stavinsky, A; Stepanyan, S S; Stepanyan, S; Stokes, B E; Stoler, P; Strakovsky, I I; Strauch, S; Suleiman, R; Taiuti, M; Tedeschi, D J; Thoma, U; Tkabladze, A; Tkachenko, S; Todor, L; Tur, C; Ungaro, M; Vanderhaeghen, M; Vineyard, M F; Vlassov, A V; Watts, D P; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zana, L; Zhang, J; Zhao, B; Zhao, Z

    2006-08-18

    The longitudinal target-spin asymmetry AUL for the exclusive electroproduction of high-energy photons was measured for the first time in ep-->e;'pgamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sinvarphi moment is 0.252+/-0.042stat+/-0.020sys. Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions H and H. PMID:17026221

  9. Nuclear isomerism in fission fragments produced by the spontaneous fission of {sup 252}Cf; Isomerisme nucleaire dans les fragments de fission produits dans la fission spontanee du {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Gautherin, C

    1997-09-01

    This thesis is devoted to the study of the nuclear structure of neutron-rich nuclei, via the search of isomeric nuclear states. Neutron-rich nuclei were produced in the spontaneous fission of {sup 252}Cf. The experimental study of isomeric states in these nuclei was performed with the {gamma}-array EUROGAM II, coupled to an additional and original fission fragment detector composed by photovoltaic cells, SAPhIR. The photovoltaic cells are well adapted to detect low energy heavy ions and have good energy and time resolutions to obtain a good fission fragment detection. This experiment led to the discovery of new isomeric states in {sup 135}Xe, {sup 104}Mo, {sup 146,147,148}Ce and {sup 152,154,156}Nd, with lifetimes between 60 ns and 2 {mu}s. Level schemes of these nuclei have been completed. An interpretation of the isomeric states in the nuclei {sup 154,156}Nd and {sup 156,158}Sm was performed by Hartree-Fock-Bogolyubov calculations using the DIS Gogny force with two quasi-particles excitations. The confrontation with the experimental results led to an interpretation of these isomeric states as K-isomers. (author)

  10. Effective neutron targets

    International Nuclear Information System (INIS)

    Because of the lack of a free neutron target, deuterium targets have been used extensively in studying the neutron structure. The unique spin structure of the 3He ground state wave function and the recent developments in laser technologies made polarized 3He targets widely used in many experiments from neutron electromagnetic form factor studies to nucleon spin structure function measurements at all major electron accelerator facilities. In this talk, the current status of the polarized 3He targets will be reviewed. The author will focus on neutron electromagnetic form factor studies using polarized 3He targets. The polarized nucleon spin structure function measurements using polarized 3He targets will also be discussed

  11. Survival of clonogenic cells of Lewis lung carcinoma forming colonies in agar cultures in diffusion chambers after γ- and γ-neutron (252Cf)-irradiation

    International Nuclear Information System (INIS)

    Clonogenic cells forming colonies in agar cultures in diffusion chambers and those isolated from subcutaneously transplanted Lewis lung carcinoma do not differ in their sensitivity to 60Co γ-rays with respect to tumor growth stages. The dose-survival curves for all studied cells are S-shaped with a small shoulder. A cumulative dose-survival curve for malignant clonogenic cells is characterized by the average value of mean lethal dose D0=2.24 Gy and extrapolation number n=2.0. When exposed to γ-neutron-radiation (252Cf) malignant clonogenic cells exhibit a nearly exponential dose-survival curve with D0=0.56 Gy (with respect to a neutron component). The RBE of γ-neutron radiation (252Cf) is 2.5

  12. Project 252Cf-D2O. The multisphere system of neutron dosimetry and spectrometry (M.S.-N.D.S.). Studies of applications to health physics

    International Nuclear Information System (INIS)

    The project 252Cf-D2O is articulated upon the utilization of a 200μg nominal 252Cf spontaneous neutron fission source, used bare and under D2O spherical moderators, giving leakage neutron spectra experimentally known and/or calculated. This project has for objective the applications of those sources to Health Physics, in dosimetry (calibration of ''rad'' and ''rem-meters'') and in spectrometry, associated with the experimental system of measurements made by the generalization of the BONNER Spheres, known as ''the Multisphere System''. This communication describes the normalization method used and the results obtained leading to the adoption of a reference matrix called ''the Log-Normal Multisphere Matrix'' (LN-MM) giving the energies response functions of the generalized system for all the spheres diameters between 40 and 400 millimeters and for all the energies between 0.4eV and 15MeV

  13. The measurement of tritium produced in a 6LiD sphere irradiated by neutrons from D-D and 252Cf

    International Nuclear Information System (INIS)

    In a 6LiD sphere irradiated by neutrons from D-D and 252Cf, tritium production rate and tritium production distribution were measured with 6LiI(Eu) scintillation detector. The measurement shows that the tritium production rate is 0.98 +- 0.05 with 252Cf neutrons and the average tritium production rate is 0.96 +- 0.07 with D-D neutrons. Moreover, the two dimensional measurement particle identification technique was used. The result shows that the measured value of tritium production rate is in accord with the theoretical calculating one within the experimental error range while in the areas of various radius, the tritium production distributions are different from each other. The experimental results can be used for correcting the group constant of neutron production tritium and checking relevant theoretical calculating method. (2 tabs., 7 figs.)

  14. Molecular Targets for Targeted Radionuclide Therapy

    International Nuclear Information System (INIS)

    Molecular targeted radionuclide cancer therapy is becoming of increasing importance, especially for disseminated diseases. Systemic chemotherapies often lack selectivity while targeted radionuclide therapy has important advantages as the radioactive cytotoxic unit of the targeting vector is specifically directed to the cancer, sparing normal tissues. The principle strategy to improve cancer selectivity is to couple therapeutic agents to tumour-targeting vectors. In targeted radionuclide therapy (TRT), the cytotoxic portion of the conjugates normally contains a therapeutic radiometal immobilised by a bifunctional chelator. The aim is therefore to use as ligand-targeted therapeutics vectors coupled to Auger-, alpha- and/or beta-emitting radionuclides. An advantage of using radiation instead of chemotherapeutics as the cytotoxic agent is the so called 'crossfire effect'. This allows sterilisation of tumour cells that are not directly targeted due to heterogeneity in target molecule expression or inhomogeneous vector delivery. However, before the targeting ligands can be selected, the target molecule on the tumour has to be selected. It should be uniquely expressed, or at least highly overexpressed, on or in the target cells relative to normal tissues. The target should be easily accessible for ligand delivery and should not be shed or down- regulated after ligand binding. An important property of a receptor (or antigen) is its potential to be internalized upon binding of the ligand. This provides an active uptake mechanism and allows the therapeutic agent to be trapped within the tumour cells. Molecular targets of current interest include: Receptors: G-protein coupled receptors are overexpressed on many major human tumours. The prototype of these receptors are somatostatin receptors which show very high density in neuroendocrine tumours, but there are many other most interesting receptors to be applied for TRT. The targeting ligands for these receptors are

  15. Biological, chemical and other data collected aboard the THOMAS G. THOMPSON during cruise TN252 in the Coastal Waters of SE Alaska and North Pacific Ocean from 2010-07-26 to 2010-08-23 (NODC Accession 0104356)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC accession 0104356 includes biological, chemical, optical, physical and underway data collected aboard the THOMAS G. THOMPSON during cruise TN252 in the Coastal...

  16. Measurement of the neutron spectrum and ambient neutron dose rate equivalent from the small 252Cf source at 1 meter

    Energy Technology Data Exchange (ETDEWEB)

    Radev, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-07

    NASA Langley Research Center requested a measurement of the neutron spectral distribution and fluence from the 252Cf source (model NS-120, LLNL serial # 7001677, referred as the SMALL Cf source) and determination of the ambient neutron dose rate equivalent and kerma at 100 cm for the Radiation Budget Instrument Experiment (Rad-X). The dosimetric quantities should be based on the neutron spectrum and the current neutron-to-dose conversion coefficients.

  17. Power spectral density measurements with 252Cf for unreflected 17.77-cm-dia uranium (93.2 wt % 235U) metal cylinders

    International Nuclear Information System (INIS)

    The method of reactivity determination using noise analysis correlation measurements with 252Cf was used to determine the reactivity for subcritical 17.77-cm-dia uranium (93.2 wt percent 235U) metal cylinders with reactivities as low as 25 dollars. Far subcritical tests were performed with right circular cylinders of uranium metal for which the subcritical reactivity was known from other inverse kinetics and prompt neutron decay constant measurements

  18. Determining the neutron spectrum of 241Am-Be and 252Cf sources using bonner sphere spectrometer

    Directory of Open Access Journals (Sweden)

    M.A Varshabi

    2016-06-01

    Full Text Available Bonner spheres system is one of the ways of measuring neutron energy distribution which is often applied in spectrometry and neutron dosimetry. This system includes a thermal neutron detector, being located in the center of several polyethylene spheres, and it is still workable due to the isotropic response of the system which in turn is derived from the spherical symmetry of moderators and the broad measurable range of the energy. In order to practically use this spectrometer, it is necessary to calibrate this system using standard neutron sources. This research aimed to determine the calibration factor of Bonner spheres spectrometry system and energy spectrum of two standard 241Am-Be and 252Cf sources in the atomic energy organization. Calibration and experimental measurement were done via the two standard sources. The response vector of each detector was derived by using MCNPX simulation code, based on the Monte Carlo method. The spectra unfolding of this system was performed through iterative method using the SPUNIT code done in software NSDUAZ6LiI and BUMS. 

  19. Preliminary study on biological effects of pea seeds (Pisum sativum L.) induced by 252Cf neutron source

    International Nuclear Information System (INIS)

    Background: The doses and biological effects of irradiated plants have been studied and reported widely. In the research, Co-60 gamma-ray source was more often used than the neutron source. However, fast neutron source is promising in such irradiation studies as it has many advantages, such as strong biological effect, high mutation rate, wide variation spectrum and stable mutant. Purpose: We aim to explore the method of dose calculation in pea samples. The biological effects of pea seeds (Pisum sativum L.) induced by different radioactive doses are to be investigated. Methods: The Needle Leaf Pea seeds were irradiated using 252Cf fission neutron source. The Monte Carlo simulation MCNP4C code was used to calculate the neutron absorbed doses and γ-rays (photons) absorbed doses in the samples. The biological effects of pea seeds induced by different radioactive doses were investigated. Results: The results showed that the flowering time of Ml generation peas was delayed with lower neutron absorbed doses (0.239-4.330 Gy), and the germination rate was promoted with micro-absorbed doses. The seedling branch rate of Ml generation peas was elevated by neutron radiation. The harvest of Ml generation was increased with appropriate neutron doses (0.619 Gy) irradiating peas. Conclusion: After being irradiated by low neutron doses (0.239-4.330 Gy), M1 generation peas show obvious biological effects. The research results have positive significance for the agricultural production and breeding. (authors)

  20. A cumulative analysis of odontogenic cysts from major dental institutions of Bangalore city: A study of 252 cases

    Directory of Open Access Journals (Sweden)

    Prashanth Ramachandra

    2011-01-01

    Full Text Available Background: The objective of this study was to perform a cumulative analysis of odontogenic cysts obtained from the data of major dental institutions of Bangalore city, as well as to evaluate their distribution during a 5-year period and compare the results with other international studies. Materials and Methods: Data for the study were obtained from the reports of patients diagnosed with odontogenic cysts between 2005 and 2010 from different dental institutions of Bangalore. Case records of patients that fit the histological classification of the World Health Organization (WHO (2005 were included in the study and the following variables were analyzed: age, gender, anatomic location, and histological type. Results: In a total of 252 cyst specimens diagnosed, 79.76% were odontogenic cysts and 20.24% were nonodontogenic cysts. Among the odontogenic cysts most frequent lesions were radicular cysts (50.25%, followed by keratocysts (27.36% and dentigerous cysts (22.39%. Conclusions: Our study provides a cumulative data of odontogenic cysts in the population of Bangalore city. The results of our study showed a similar frequency of odontogenic cysts as compared to other populations of the world, with radicular cyst being identified as the most frequent odontogenic cyst. Keratocyst was the second most common cyst followed by dentigerous cyst.

  1. Improved calculation of the prompt fission neutron spectrum from the spontaneous fission of /sup 252/Cf: Preliminary results

    International Nuclear Information System (INIS)

    An improved calculation is presented for the prompt fission neutron spectrum N(E) from the spontaneous fission of /sup 252/Cf. In this calculation the fission-spectrum model of Madland and Nix is used, but with several improvements leading to a physically more accurate representation of the spectrum. Specifically, the contributions to N(E) from the entire fission-fragment mass and charge distributions will be calculated instead of calculating on the basis of a seven- point approximation to the peaks of these distributions as has been done in the past. Therefore, values of the energy release in fission, fission-fragment kinetic energy, and compound nucleus cross section for the inverse process will be considered on a point-by-point basis over the fragment yield distributions instead of considering averages of these quantities over the peaks of the distributions. Preliminary results will be presented and compared with a measurement, an earlier calculation, and a recent evaluation of the spectrum. 14 refs., 4 figs

  2. Study on the effect of kidney transplantation on the health of the patients' offspring: a report on 252 Chinese children.

    Science.gov (United States)

    Xu, Longgen; Han, Peng; Liu, Yong; Wang, Hongwei; Yang, Yirong; Qiu, Feng; Peng, Wanling; Tang, Ligong; Fu, Jing; Zhu, Xiaofeng; Zhu, Youhua

    2014-01-01

    Even though the incidence of pregnancies in the female recipients is lower and also chronic renal disease in male patients is associated with impaired spermatogenesis, the health of the children born to these patients was not studied. In this report, we discuss information on the growth and development of offspring of 248 male and female kidney recipient patients. Physical and routine clinical measurements of the 252 offspring (129 male and 123 female) born to these transplantation patients were made along with the intelligence tests. In some of these children chest X-ray and immune indices were assessed. Among the recipients, 219 males fathered 223 children with an average birth weight of 3,255 ± 374 g and 29 female recipients gave birth to 29 children with an average birth weight of 2,923 ± 551. While most of these children were normal, we noticed a case of soft double toe, a case of short tongue tie, five cases of marginal mental retardation, three cases of proteinuria, six cases of microscopic hematuria, 15 cases of low hemoglobin, and 21 cases with recurrent respiratory tract infections. We conclude that kidney transplantation has no significant impact on the growth, development, health, and intelligence of the offspring born to recipients. PMID:23733673

  3. Variability of Indian summer monsoon over the past 252 kyr revealed by stalagmite record in Southwest China

    Science.gov (United States)

    Cai, Y.; Fung, I. Y.; Edwards, R.; An, Z.; Cheng, H.; Lee, J.

    2013-12-01

    Multiple proxies obtained from Arabian Sea sediments have revealed the variability of Indian summer Monsoon (ISM) on time scale of 100-105 years. These proxies mainly capture summertime winds over the Arabian Sea and our understanding of Indian summer monsoon precipitation variability; and the relationship between paleo-ISM and paleo East Asia summer monsoon (EASM) lacks precise articulation, however, due to the scarcity of high-resolution precipitation records spanning a glacial-interglacial cycle. Here, we present an absolutely-dated oxygen isotope record from stalagmites in Xiaobailong (XBL) cave, southwestern China, that documents the variability in local precipitation and the ISM for the past 252,000 years. This record is dominated by 23-kyr precessional cycles punctuated by prominent millennial-scale oscillations that are synchronous with Heinrich events in the North Atlantic. It also shows clear glacial-interglacial variations that are consistent with marine and other terrestrial proxies. The distinct glacial-interglacial range in XBL δ18O is larger than that of speleothem records from eastern China. Corroborated with results from an isotope-enabled global climate model, we hypothesize that these dissimilarities may reflect the different responses of ISM and EASM to changes in global circulation and moisture source, in particular those caused by glacial-interglacial sea-land configuration changes as manifested by notable coastline shifts in the Western Pacific and Maritime Continent.

  4. Effects of Exposure of Pink Shrimp, Farfantepenaeus duorarum, Larvae to Macondo Canyon 252 Crude Oil and the Corexit Dispersant

    Directory of Open Access Journals (Sweden)

    Susan Laramore

    2016-03-01

    Full Text Available The release of oil into the Gulf of Mexico (GOM during the Deepwater Horizon event coincided with the white and pink shrimp spawning season. To determine the potential impact on shrimp larvae a series of static acute (24–96 h toxicity studies with water accommodated fractions (WAFs of Macondo Canyon (MC 252 crude oil, the Corexit 9500A dispersant, and chemically enhanced WAFS (CEWAFs were conducted with nauplii, zoea, mysid, and postlarval Farfantepenaeus duorarum. Median lethal concentrations (LC50 were calculated and behavior responses (swimming, molting, light sensitivity evaluated. Impacts were life stage dependent with zoea being the most sensitive. Behavioral responses for all stages, except postlarvae, occurred at below LC50 values. Dispersants had the greatest negative impact while WAFs had the least. No short-term effects (survival, growth were noted for nauplii exposed to sub-lethal CEWAFs 39 days post-exposure. This study points to the importance of evaluating multiple life stages to assess population effects following contaminant exposure and further, that the use of dispersants as a method of oil removal increases oil toxicity.

  5. A comparative study on experimental and simulation responses of CR-39 to neutron spectra from a 252Cf source

    Directory of Open Access Journals (Sweden)

    Ghergherehchi Mitra

    2013-01-01

    Full Text Available A simulation of the interaction of neutrons emitted from a 252Cf source with a CR-39 detector is presented in this paper. Elastic and inelastic neutron interactions occur with the constituent materials of the CR-39 detector. Inelastic scatterings only consider (n, a and (n, p reactions. Fast neutrons tracks are, mainly, produced by recoil particle tracks in the plastic nuclear track detector as a result of the elastic scattering reaction of neutrons with the constituent materials of the solid-state nuclear track detectors, especially hydrogen nuclei. The energy of the neutron, incident position, direction, and type of interaction were sampled by the Monte Carlo method. The energy threshold, critical angle and scattering angle to the detector surface normal were the most important factors considered in our calculations. The energy deposited per neutron mass unit was calculated. The angular response was determined by both Monte Carlo simulation and experimental results. The number of visible proton tracks and energy deposited per neutron per visible track were calculated and simulated. The threshold energy of the recoil proton as a function of the thickness and incident proton angles was measured by the etchable range of protons at scattering angles, along with the shape and diameter of the track. Experimental and simulations result were in good agreement.

  6. 252Cf-source-correlated transmission measurements for uranyl fluoride deposit in a 24-in.-OD process pipe

    International Nuclear Information System (INIS)

    Characterization of a hydrated uranyl fluoride (UO2F2·nH2O) deposit in a 17-ft-long, 24-in.-OD process pipe at the former Oak Ridge Gaseous Diffusion Plant was successfully performed by using 252Cf-source-correlated time-of-flight (TOF) transmission measurements. These measurements of neutrons and gamma rays through the pipe from an external 2521Cf fission source were used to measure the deposit profile and its distribution along the pipe, the hydration (or H/U), and the total uranium mass. The measurements were performed with a source in an ionization chamber on one side of the pipe and detectors on the other. Scanning the pipe vertically and horizontally produced a spatial and time-dependent radiograph of the deposit in which transmitted gamma rays and neutrons were separated in time. The cross-correlation function between the source and the detector was measured with the Nuclear Weapons Identification System. After correcting for pipe effects, the deposit thickness was determined from the transmitted neutrons and H/U from the gamma rays. Results were consistent with a later intrusive observation of the shape and the color of the deposit; i.e., the deposit was annular and was on the top of the pipe at some locations, demonstrating the usefulness of this method for deposit characterization

  7. Feasibility of fissile mass assay of spent nuclear fuel using 252Cf-source-driven frequency-analysis

    International Nuclear Information System (INIS)

    The feasibility was evaluated using MCNP-DSP, an analog Monte Carlo transport cod to simulate source-driven measurements. Models of an isolated Westinghouse 17x17 PWR fuel assembly in a 1500-ppM borated water storage pool were used. In the models, the fuel burnup profile was represented using seven axial burnup zones, each with isotopics estimated by the PDQ code. Four different fuel assemblies with average burnups from fresh to 32 GWd/MTU were modeled and analyzed. Analysis of the fuel assemblies was simulated by inducing fission in the fuel using a 252Cf source adjacent to the assembly and correlating source fissions with the response of a bank of 3He detectors adjacent to the assembly opposite the source. This analysis was performed at 7 different axial positions on each of the 4 assemblies, and the source-detector cross-spectrum signature was calculated for each of these 28 simulated measurements. The magnitude of the cross-spectrum signature follows a smooth upward trend with increasing fissile material (235U and 239Pu) content, and the signature is independent of the concentration of spontaneously fissioning isotopes (e.g., 244Cm) and (α,n) sources. Furthermore, the cross-spectrum signature is highly sensitive to changes in fissile material content. This feasibility study indicated that the signature would increase ∼100% in response to an increase of only 0.1 g/cm3 of fissile material

  8. New source-moderator geometry to improve performance of 252Cf and 241Am-Be source-based PGNAA setups

    International Nuclear Information System (INIS)

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups

  9. New source-moderator geometry to improve performance of {sup 252}Cf and {sup 241}Am-Be source-based PGNAA setups

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Abdelmonem, M.S. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Misned, Ghada [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia); Al-Ghamdi, Hanan [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia)

    2006-06-15

    The gamma ray yield from a {sup 252}Cf and a {sup 241}Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the {sup 252}Cf and the {sup 241}Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a {sup 252}Cf and a {sup 241}Am-Be source-based PGNAA setups.

  10. Uniform detection of the pre-main sequence population in the 5 embedded clusters related to the H\\,II region NGC\\,2174 (Sh2-252)

    CERN Document Server

    Bonatto, Charles

    2011-01-01

    We investigate 5 embedded clusters (ECs) and the extended stellar group itself of the prominent H\\,II region NGC\\,2174 (Sh2-252), which presents scarce and heterogeneous information, coming from the optical and infrared. Considering the discrepant values of distance and age, the clusters and the H\\,II region appear to be physically unrelated. The analysis is based on field-star decontaminated 2MASS photometry, which allows sampling the pre-main sequence (PMS). We find that Sh2-252A, C, E, NGC\\,2175s, and Teu\\,136 are small ECs (radius within $1.0 - 2.3$\\,pc) characterised by a similar age ($\\sim5$\\,Myr), reddening ($\\aV\\sim1$), distance from the Sun ($\\ds\\sim1.4$\\,kpc), and low mass ($60-200\\,\\ms$). This age is consistent with the H\\,II region, the presence of O and B stars still in the MS, and the dominance ($\\ga95%$ in number) of PMS stars in colour-magnitude diagrams (CMDs). NGC\\,2175 is not a star cluster, but an extended stellar group that encompasses the ECs Sh2-252\\,A and C. It contains $\\sim36%$ of th...

  11. Study of the applicability of the 252Cf neutron source for the determination of the concentration of disolved substances by means of π,α reactions

    International Nuclear Information System (INIS)

    For the determination of the interphase concentration for mass transfer in extraction systems α-particles generated by a n,α nuclear reaction are used. The study described tries to use 252Cf as a neutron source instead of the nuclear reactor previously used by Greger. The measuring technique is based on the generation of α particles and γ quanta by neutron irradiation of a phase containing 10B or 6Li compounds, the production of a sufficiently large number of α particles as well as the suppression of a high background of recoil protons still making difficulties at present. The particles generated are to be detected by means of liquid scintillation measuring technique and separated from each other by a pulse shaping analysis. In addition the design of a compact irradiation device is described allowing to perform measurements by means of a small 252Cf neutron source in a relatively modestly equipped isotope laboratory. In the set-up described in this paper the neutron source, unlike other, similar devices, is brought to the measuring position only during the period of measurement, using a pneumatic transport facility. The results obtained have shown that by using 252Cf as a neutron source for the method of measurement developed by Greger there are still no satisfactory results. (orig./RB)

  12. Price level targeting

    OpenAIRE

    Shukayev, Malik; Ueberfeldt, Alexander

    2010-01-01

    Various papers have suggested that Price-Level targeting is a welfare improving policy relative to Inflation targeting. From a practical standpoint, this raises an important yet unanswered question: What is the optimal price index to target? This paper derives the optimal price level targeting index defined over the eight main components of the Consumer Price Index. It finds that such an index places a heavier weight, relative to the expenditure weight, on sectors with slow price adjustments....

  13. Multilayer polymer microspot targets

    International Nuclear Information System (INIS)

    Last year the authors reported on the development of a seeded microspot x-ray diagnostic target. This target consisted of a 300-μm-diam, 2-μm-thick disk of silicon or sulfur-seeded hydrocarbon polymer nested tightly in a hole in a 2-μm-thick film of pure hydrocarbon polymer. This year they extended our work on the microspot target, fully encapsulating the microspot in what they call the multilayer polymer microspot target

  14. Target Price Accuracy

    OpenAIRE

    Alexander G. Kerl

    2011-01-01

    This study analyzes the accuracy of forecasted target prices within analysts’ reports. We compute a measure for target price forecast accuracy that evaluates the ability of analysts to exactly forecast the ex-ante (unknown) 12-month stock price. Furthermore, we determine factors that explain this accuracy. Target price accuracy is negatively related to analyst-specific optimism and stock-specific risk (measured by volatility and price-to-book ratio). However, target price accuracy is positive...

  15. The Targeting of Advertising

    OpenAIRE

    Ganesh Iyer; David Soberman; J. Miguel Villas-Boas

    2005-01-01

    An important question that firms face in advertising is developing effective media strategy. Major improvements in the quality of consumer information and the growth of targeted media vehicles allow firms to precisely target advertising to consumer segments within a market. This paper examines advertising strategy when competing firms can target advertising to different groups of consumers within a market. With targeted advertising, we find that firms advertise more to consumers who have a st...

  16. TARGET COSTING FUNCTIONS

    OpenAIRE

    Dimi OFILEANU

    2015-01-01

    This article aims to highlight the concept of Target Costing. Based on the characteristics of Target Costing, identified in specialized literature, the article presents its main advantages and disadvantages. Also, a comparison is being made between Target Cost and Traditional Cost (in its traditional form, the cost represents an independent variable on the basis of which the sell price is established; and in the Target Cost form the cost represents a dependent variable which is determined on ...

  17. An actionable climate target

    Science.gov (United States)

    Geden, Oliver

    2016-05-01

    The Paris Agreement introduced three mitigation targets. In the future, the main focus should not be on temperature targets such as 2 or 1.5 °C, but on the target with the greatest potential to effectively guide policy: net zero emissions.

  18. 252 Cases of Trace Elements in Peripheral Blood of Children and Correlation Analysis Results%252例儿童末梢血微量元素的检测结果及相关性分析

    Institute of Scientific and Technical Information of China (English)

    汪玥

    2012-01-01

      Objective In order to understand our city children aged 0 to 7,trace elements intake, clinical guidance, selective reasonable to add trace elements for children. Methods The children randomly selected pediatric patient health cards and children aged 0 to 7 252 cases, using Beijing Optoelectronic Technology Co,Ltd. Bo Hui innovative products BH5100T type five-channel atomic absorption spectrometry for zinc, iron, calcium, magnesium, copper 5 Detection of trace elements, and do statistical analysis. Results The children in our city there are different levels of trace element deficiency, including zinc, iron, calcium deficiency is the most serious, rates were 48.4%,50.8% and 47.6%, lack of magnesium and lack of copper lower incidences of 7.1 per cent, respectively with 9.5%;the results show that various micronutrient deficiencies in the gender difference was not statistically significant(P>0.05). Conclusion The results show that the intake of trace elements in our city children can not be optimistic,reasonable to add trace elements, can effectively prevent children from lack of trace elements, trace elements to prevent the abuse of excessive complement blindness.%  目的为了解我市0~7岁儿童微量元素摄入情况,指导临床,有选择性的给儿童合理补充微量元素.方法随机抽查儿保健卡和儿科门诊的0~7岁儿童252例,利用北京博晖创新光电技术股份有限公司生产的 BH5100T 型五通道原子吸收光谱仪进行锌、铁、钙、镁、铜五种微量元素的检测,并做统计学分析.结果我市儿童存在不同程度的微量元素缺乏情况,其中锌、铁、钙缺乏情况最为严重,发生率分别为48.4%、50.8%和47.6%,缺镁和缺铜的发生率较低,分别为7.1%和9.5%;分析发现各种微量元素缺乏在性别上差异无显著性(P>0.05).结论分析结果表明我市儿童的微量元素摄入不均衡,合理补充微量元素,可以有效的防止儿童微量元

  19. A Monte Carlo comparison of PGNAA system performance using 252Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Science.gov (United States)

    Naqvi, A. A.

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a 252Cf neutron and a 14-MeV neutron-based prompt γ-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a 252Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt γ-ray yields from the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt γ-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the 252Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  20. A Monte Carlo comparison of PGNAA system performance using {sup 252}Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a {sup 252}Cf neutron and a 14-MeV neutron-based prompt {gamma}-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a {sup 252}Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt {gamma}-ray yields from the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt {gamma}-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the {sup 252}Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  1. Targeted cancer therapies

    Institute of Scientific and Technical Information of China (English)

    Li Yan; Neal Rosen; Carlos Arteaga

    2011-01-01

    With unprecedented understanding of molecular events underlying human cancer in this genomic era, a large number of drugs specifically targeting hypothesized oncogenic drivers to which tumors are potentially addicted to have been developed and continue to be developed. These targeted cancer therapies are being actively tested in clinical trials with mixed successes. This editorial provides an overview on successful targeted cancer drugs on the market and those drugs that are in late clinical development stages. Importantly, the article lays out main challenges in developing molecular targeted therapies and potential path forward to overcome these challenges, as well as opportunities for China in this new era of targeted agents. The editorial serves as an introduction to the Targeted Cancer Therapies serias that will review in depth of major pathways and drugs targeting these pathways to be published in the coming issues of the Chinese Journal of Cancer.

  2. Polarized targets and beams

    International Nuclear Information System (INIS)

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  3. Simultaneous utilization of neutrons and γ-rays from 252Cf for condition measurement inside a blast furnace

    International Nuclear Information System (INIS)

    This paper describes the possibility of the realization of a multi-function radiation gauge to meet the requirement for more precise and stable control of a blast furnace. A basic concept of the gauge is to measure some quantities with simultaneous use of multi-radiations of neutrons and γ-rays, and to obtain multi-types of information on material flow and gas flow representing the conditions inside the blast furnace. The prototype gauge was assembled and examined which consisted of a radiation source of 252Cf (3.7 MBq), neutron moderator, lead shield, a bismuth germanate detector, stainless casing and a control unit. Laboratory experiments showed that the gauge could measure the quantities to be essential to estimate the blast furnace conditions. In practice, it clearly distinguished between iron ore and coke layers, and at the same time measured bulk density (1.0-1.5 g/cm3) of iron contained in iron ore by counting thermal neutron capture γ-rays (6.5-8.5 MeV) from iron. It also gave the information on material bulk density (0.5-2.5 g/cm3) by detecting Compton scattered γ-rays (1.0-1.5 MeV) from material, i.e. iron ore and coke. The relative accuracies in the measurement of iron bulk density and material bulk density were estimated to be within 1 and 4% in 300 s counting time, respectively. The possibility of the gauge has been proved and the on-line trial will be expected in the near future. (author)

  4. Multi-technique characterization of neutron fields from moderated 252Cf and 238PuBe sources

    International Nuclear Information System (INIS)

    At the Lawrence Livermore Laboratory, 252Cf and 238PuBe neutron sources are used for calibration of personnel neutron dose meters and neutron monitoring instrumentation. The sources with emission rates of approximately 2x109 and 2x107 n.s-1, respectively, have been calibrated by the United States National Bureau of Standards. The sources are transferred into a 815 m3 concrete calibration cell through a remotely operated pneumatic system. Calibrations can be made without source moderation, or with spherical moderators of aluminium, polyethylene, water or deuterium oxide placed over the end of the pneumatic irradiation tube. The source is located in the tube at one metre above a false floor in the centre of the cell. Nine different moderators are available in sizes up to 56 cm in diameter. Several techniques have been used to characterize the neutron fields produced by each source-moderator configuration to improve the quality of our calibrations. Measurements and calculations have been made to determine neutron flux, kerma rate, neutron spectrum, quality factor, dose equivalent rate and linear energy transfer (LET) spectrum. Neutron spectra are determined by: (1) Calibration using the ANISN discrete ordinates transport code, (2) Bonner sphere measurements using the LOUHI unfolding code, and (3) measurement with proton recoil counters and liquid scintillation detectors. The spectra are then folded into published energy dependent conversion factors to yield kerma, quality factor and dose equivalent values. We obtain LET spectra using a tissue-equivalent LET chamber and the GANDALF unfolding code. Chamber data are used to determine kerma and quality factor. Finally, an 80 cm3 tissue-equivalent ion chamber and neutron-insensitive Geiger counter are used to measure the neutron kerma. Results of the various techniques are presented and compared. In addition, comparisons are made with results obtained from conventional health physics instrumentation such as moderated rem

  5. Application of PGNAA to preincineration assay of combustible waste for chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, R.J.; Pawelko, R.J.; Greenwood, R.C. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-12-31

    A prompt gamma neutron activation analysis method is being developed for on-stream pre-incineration assay of low level radioactive combustible waste for it`s chlorine content. The assay system consists of three californium 252 sources and a germanium or scintillation gamma-ray spectrometer.

  6. GWAS and drug targets

    OpenAIRE

    Cao, Chen; Moult, John

    2014-01-01

    Background Genome wide association studies (GWAS) have revealed a large number of links between genome variation and complex disease. Among other benefits, it is expected that these insights will lead to new therapeutic strategies, particularly the identification of new drug targets. In this paper, we evaluate the power of GWAS studies to find drug targets by examining how many existing drug targets have been directly 'rediscovered' by this technique, and the extent to which GWAS results may ...

  7. Deuterium high pressure target

    International Nuclear Information System (INIS)

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  8. Inertial Confinement fusion targets

    Science.gov (United States)

    Hendricks, C. D.

    1982-01-01

    Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques were devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems, and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

  9. Deuterium High Pressure Target

    CERN Document Server

    Perevozchikov, V; Vinogradov, Yu I; Vikharev, M D; Ganchuk, N S; Golubkov, A N; Grishenchkin, S K; Demin, A M; Demin, D L; Zinov, V G; Kononenko, A A; Lobanov, V N; Malkov, I L; Yukhimchuk, S A

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm^3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system.

  10. The ISOLDE target robots

    CERN Multimedia

    Maximilein Brice

    2002-01-01

    ISOLDE targets need to be changed frequently, around 80 times per year. The high radiation levels do not permit this to be done by human hands and the target changes are effected by 2 industrial robots (picture _01). On the left, in the distance, the front-end of the GPS (General Purpose Separator) is seen, while the HRS (High Resolution Separator) is at the right. Also seen are the doors to the irradiated-target storage.

  11. Moving Target Defense

    CERN Document Server

    Jajodia, Sushil; Swarup, Vipin; Wang, Cliff; Wang, X Sean

    2011-01-01

    Moving Target Defense: Creating Asymmetric Uncertainty for Cyber Threats was developed by a group of leading researchers. It describes the fundamental challenges facing the research community and identifies new promising solution paths. Moving Target Defense which is motivated by the asymmetric costs borne by cyber defenders takes an advantage afforded to attackers and reverses it to advantage defenders. Moving Target Defense is enabled by technical trends in recent years, including virtualization and workload migration on commodity systems, widespread and redundant network connectivity, instr

  12. Target Window Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-11

    The target window design implemented and tested in experiments at ANL have performed without failure for the available beam of 6 mm FWHM on a 12 mm diameter target. However, scaling that design to a 25 mm diameter target size for a 12 mm FWHM beam has proven problematic. Combined thermal and mechanical (pressure induced) stresses and strains are too high to maintain the small coolant gaps and provide adequate fatigue lifetime.

  13. Target Assembly Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Target Assembly Facility integrates new armor concepts into actual armored vehicles. Featuring the capability ofmachining and cutting radioactive materials, it...

  14. Targeting the tumor microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, P.A.; Lee, G.Y.; Bissell, M.J.

    2006-11-07

    Despite some notable successes cancer remains, for the most part, a seemingly intractable problem. There is, however, a growing appreciation that targeting the tumor epithelium in isolation is not sufficient as there is an intricate mutually sustaining synergy between the tumor epithelial cells and their surrounding stroma. As the details of this dialogue emerge, new therapeutic targets have been proposed. The FDA has already approved drugs targeting microenvironmental components such as VEGF and aromatase and many more agents are in the pipeline. In this article, we describe some of the 'druggable' targets and processes within the tumor microenvironment and review the approaches being taken to disrupt these interactions.

  15. Bayesian multiple target tracking

    CERN Document Server

    Streit, Roy L

    2013-01-01

    This second edition has undergone substantial revision from the 1999 first edition, recognizing that a lot has changed in the multiple target tracking field. One of the most dramatic changes is in the widespread use of particle filters to implement nonlinear, non-Gaussian Bayesian trackers. This book views multiple target tracking as a Bayesian inference problem. Within this framework it develops the theory of single target tracking, multiple target tracking, and likelihood ratio detection and tracking. In addition to providing a detailed description of a basic particle filter that implements

  16. The Target Visitation Problem

    OpenAIRE

    Hildenbrandt, Achim

    2015-01-01

    The thesis considers the target visitation problem, a combinatorial optimization problem, which merges the classical traveling salesman problem with the linear ordering problem. In more detail, we are looking for a tour which visits a set of targets and which is optimal with respect to two different aspects: On the one hand, we have given a travel cost from each target to every other. On the other hand, we have preference values which tell us how much we would like to visit one target before ...

  17. Strategic Targeted Advertising

    NARCIS (Netherlands)

    A. Galeotti; J.L. Moraga-Gonzalez (José Luis)

    2003-01-01

    textabstractWe present a strategic game of pricing and targeted-advertising. Firms can simultaneously target price advertisements to different groups of customers, or to the entire market. Pure strategy equilibria do not exist and thus market segmentation cannot occur surely. Equilibria exhibit rand

  18. Pure HD polarized targets

    International Nuclear Information System (INIS)

    The HD polarized target project is now ready to use a target in a physics experiment. This must be done in early 1998 at LEGS (BNL). The IPN cryogenic group takes its part in this venture by doing the transfer and in-beam cryostats. (authors)

  19. The CNGS target

    CERN Multimedia

    Patrice Loïez

    2005-01-01

    The CERN Neutrinos to Gran Sasso (CNGS) target ‘magazine’ of five target units. Each unit contains a series of 10-cm long graphite rods distributed over a length of 2 m. It is designed to maximize the number of secondary particles produced and hence the number of neutrinos. One unit is used at a time to prevent over heating.

  20. Californium-based neutron radiography for corrosion detection in aircraft

    International Nuclear Information System (INIS)

    In support of an overall program aimed at minimizing disassembly and reducing inspection time during aircraft maintenance, a series of projects has been carried out to determine the feasibility of applying neutron radiographic techniques to the nondestructive (NDT) inspection of aircraft and aircraft components. These investigations have clearly demonstrated the superiority of neutron radiography over all other NDT techniques in its ability to detect surface and subsurface corrosion in aircraft structure. This capability is particularly significant where the corrosion is hidden behind thick metallic structural members. The neutron radiographic technique has been applied successfully to detect corrosion in the wing tank of E-2C, C-130, and DC-9 aircraft; rear stabilators of F-4 and F-111 aircraft; aft spar, starboard and port wing, and rudder of the F-8; fuselage skin of the 727; rotary blades of AH-1 and SH-3 helicopters; rotary tail flaps of the UH-2 helicopter; and nose landing gear of A-7 aircraft

  1. Targeted therapy in lymphoma

    Directory of Open Access Journals (Sweden)

    Cavalli Franco

    2010-11-01

    Full Text Available Abstract Discovery of new treatments for lymphoma that prolong survival and are less toxic than currently available agents represents an urgent unmet need. We now have a better understanding of the molecular pathogenesis of lymphoma, such as aberrant signal transduction pathways, which have led to the discovery and development of targeted therapeutics. The ubiquitin-proteasome and the Akt/mammalian target of rapamycin (mTOR pathways are examples of pathological mechanisms that are being targeted in drug development efforts. Bortezomib (a small molecule protease inhibitor and the mTOR inhibitors temsirolimus, everolimus, and ridaforolimus are some of the targeted therapies currently being studied in the treatment of aggressive, relapsed/refractory lymphoma. This review will discuss the rationale for and summarize the reported findings of initial and ongoing investigations of mTOR inhibitors and other small molecule targeted therapies in the treatment of lymphoma.

  2. Isolation and purification of the xenon fraction of 252Cf spontaneous fission products for the production of radioactive xenon calibration standards

    International Nuclear Information System (INIS)

    Idaho National Laboratory (INL) produces 135Xe, 133mXe, 133Xe, and 131mXe standards for the calibration and testing of the collection equipment and analytical techniques used to monitor radioactive xenon emissions. At INL, xenon is produced and collected as one of several spontaneous fission products from a 252Cf source in a stagnant volume of pressurized helium. Solids are separated from gases by sintered steel filtration. Further chromatographic purification of the fission gases separates the xenon fraction for selective collection. An explanation of gas system, separation, and purification is presented. 135Xe and 133Xe activity ratio adjustments are explained. (author)

  3. Fine frequency tuning in sum-frequency generation of continuous-wave single-frequency coherent light at 252 nm with dual-wavelength enhancement.

    Science.gov (United States)

    Kumagai, Hiroshi

    2007-01-01

    Fine frequency tuning of the deep-ultraviolet single-mode coherent light at 252 nm was conducted through the PID feedback system automatically by changing the temperature of a beta-BaB(2)O(4) (BBO) crystal in a doubly resonant external cavity for the sum-frequency mixing of 373 and 780 nm light. The temperature-dependent frequency tuning rate is 19.3 MHzK(-1), which is sufficiently fine to realize the laser cooling of neutral silicon atoms because the natural width of the laser cooling transition is 28.8 MHz. PMID:17167584

  4. A new shipping container for an intense neutron emitter

    International Nuclear Information System (INIS)

    Californium-252 is an intense neutron emitter (2.34 x 1012 n/s·g) used in medicine, research, and industry. The western world's sole source of this rare radioisotope is the Californium Facility at Oak Ridge National Laboratory's Radiochemical Engineering Development Center (REDC). A project has been initiated at the REDC to design a new Type B Californium Shipping Container. This effort is essential for future transportation of californium to meet the needs of users all over the world. The shipping container must meet all requirements for transport by motor freight, air, vessel, and rail, both domestic and foreign. There are unique problems in the design, fabrication, and licensing of a new Type B shipping container that will accommodate up to 60 milligrams of californium-252. One of the first challenges in the design phase of the project is the selection of a material to shield the high neutron flux. The more stringent safety precautions of today's world impel us to consider more exotic materials for such a purpose. The candidate materials must be examined not just for their neutron shielding properties, but also in conjunction with other properties such as thermal and structural requirements to withstand the hypothetical accident conditions. The design and building of such a container is a formidable task requiring much planning. The licensing process, with the complex, interactive federal codes, is a special challenge and may be the biggest on the project in terms of time and money

  5. Probe data: 252 [RED

    Lifescience Database Archive (English)

    Full Text Available R09-033840-1AR RED AU162299 AU030444 E51070 EG1070 >AE000968_9(AE000968|pid:g2648586) Archaeoglo ... similar to GB:L77117 SP:Q57665 PID:1498988 percent identity : 60.92; identified by sequence similarity; putativ ...

  6. AA antiproton production target

    CERN Multimedia

    1979-01-01

    The first version of the antiproton production target was a tungsten rod, 11 cm long and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing of stainless steel. At the entrance to the target assembly was a scintillator screen, imprinted with circles every 5 mm in radius, which allowed to precisely aim the 26 GeV high-intensity proton beam from the PS onto the centre of the target rod. The scintillator screen was a 1 mm thick plate of Cr-doped alumina. See also 7903034 and 7905091.

  7. Targeted therapies for cancer

    Science.gov (United States)

    ... to be untrue. Possible side effects from targeted therapies include: Diarrhea Liver problems Skin problems such as rash, dry skin, and nail changes Problems with blood clotting and wound healing High blood pressure As with any treatment, you ...

  8. SETI target selection.

    Science.gov (United States)

    Latham, D. W.; Soderblom, D. R.

    1995-06-01

    The NASA High Resolution Microwave Survey consists of two complementary elements: a Sky Survey of the entire sky to a moderate level of sensitivity; and a Targeted Search of nearby stars, one at a time, to a much deeper level of sensitivity. The authors propose strategies for target selection with two goals: to improve the chances of successful detection of signals from technical civilizations that inhabit planets around solar-type stars, and to minimize the chances of missing signals from unexpected sites.

  9. High pressure gas target

    Science.gov (United States)

    Gelbart, W.; Johnson, R. R.; Abeysekera, B.

    2012-12-01

    Compact, high pressure, high current gas target features all metal construction and semi-automatic window assembly change. The unique aspect of this target is the domed-shaped window. The Havar alloy window is electron beam welded to a metal ring, thus forming one, interchangeable assembly. The window assembly is sealed by knife-edges locked by a pneumatic toggle allowing a quick, in situ window change.

  10. Influence of paternal 252Cf neutron exposure on abnormal sperm, embryonal lethality, and liver tumorigenesis in the F1 offspring of mice

    International Nuclear Information System (INIS)

    Experiments were conducted to determine whether neutron-induced genetic damage in parental germline cells can lead to the development of cancer in the offspring. Seven-week-old C3H male mice were irradiated with 252Cf neutrons at a dose of 0, 50, 100, or 200 cGy. Two weeks or 3 months after irradiation, the male mice were mated with virgin 9-week-old C57BL females. Two weeks after irradiation, the irradiated male mice showed an increased incidence of sperm abnormalities, which led to embryo lethalities in a dose-dependent manner when they were mated with unirradiated female mice. Furthermore, liver tumors in male offspring of male mice in the 50 cGy group were significantly increased in 19 of 44 (43.2%) animals, in clear contrast to the unirradiated group (1 of 31; 3.2%) (P1 generation may be caused by genetic transmission of hepatoma-associated trait (s) induced by 252Cf neutron irradiation. (author)

  11. True ternary fission, the collinear decay into fragments of similar size in the 252Cf(sf) and 235U(nth, f) reactions

    International Nuclear Information System (INIS)

    The collinear cluster decay in 252Cf(sf, fff), with three cluster fragments of different masses (e.g. 132Sn, 52–48Ca, 68–72Ni), which has been observed by the FOBOS group in JINR, has established a new decay mode of heavy nuclei, the collinear cluster tripartition (CCT). The same type of ternary fission decay has been observed in the reaction 235U(nth, fff). This kind of “true ternary fission” of heavy nuclei has been predicted many times in theoretical works during the last decades. In the present note we discuss true ternary fission (TFFF) into three nuclei of almost equal size (e.g. Z=98→Zi=32, 34, 32) in the same systems. The possible fission channels are predicted from potential-energy (PES) calculations. These PES's show pronounced minima for several ternary fragmentation decays, e.g. for 252Cf(sf) and for 235U(nth, f). They suggest the existence of a variety of collinear ternary fission modes. The TFFF-decays chosen in this letter have very similar dynamical features as the previously observed collinear CCT-decays. The data obtained in the above mentioned experiments allow us to extract the yield for these TFFF-decays in both systems by using specific gates on the measured parameters. These yields are a few 1.0⋅10−6/(binary fission)

  12. Equilibration in the reaction of 175 and 252 MeV /sup 20/Ne with /sup 197/Au. [Energy, element, and angular distributions

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, J.B.

    1978-06-01

    The highly inelastic nuclear reaction of /sup 197/Au with /sup 20/Ne at 175 and 252 MeV laboratory energies is studied. Energy-, elemental-, and angular- distributions for atomic numbers 5 to 30 (175 MeV) or 34 (252 MeV) are presented. The means and widths of the kinetic energy spectra for detected elements are compared with a theoretical calculation. The calculation postulates thermalization of the incident projectile kinetic energy, and includes one sha(e-vibrational degree of freedom and rigid rotation of the reaction complex. The effect of particle evaporation is considered. Good agreement of the expurimental mean energies with the theory is obtained. Poorer agreement of the kinetic energy widths with the theory may be due to a low-temperature quantal effect. The relative elemental yields are analyzed for their degree of equilibration, based on a model of diffusive nucleon exchange as described by the master equation. A similar degree of equilibration is observed for both reaction energies. The absolute elemental yields are reproduced qualitatively by employing an advanced diffusion code, coupled with calculation of the subsequent fission of heavy reaction products, including the compound nucleus. The angular distributions are analyzed with a simple model, to estimate the reaction lifetime of selected elements.

  13. Rapid Evolution to Blast Crisis Associated with a Q252H ABL1 Kinase Domain Mutation in e19a2 BCR-ABL1 Chronic Myeloid Leukaemia

    Directory of Open Access Journals (Sweden)

    Sarah L. McCarron

    2013-01-01

    Full Text Available A minority of chronic myeloid leukaemia (CML patients express variant transcripts of which the e19a2 BCR-ABL1 fusion is the most common. Instances of tyrosine kinase inhibitor (TKI resistance in e19a2 BCR-ABL1 CML patients have rarely been reported. A case of e19a2 BCR-ABL1 CML is described in whom imatinib resistance, associated with a Q252H ABL1 kinase domain mutation, became apparent soon after initiation of TKI therapy. The patient rapidly transformed to myeloid blast crisis (BC with considerable bone marrow fibrosis and no significant molecular response to a second generation TKI. The clinical course was complicated by comorbidities with the patient rapidly succumbing to advanced disease. This scenario of Q252H-associated TKI resistance with rapid BC transformation has not been previously documented in e19a2 BCR-ABL1 CML. This case highlights the considerable challenges remaining in the management of TKI-resistant BC CML, particularly in the elderly patient.

  14. An ISOLDE target unit

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    A good dozen different targets are available for ISOLDE, made of different materials and equipped with different kinds of ion-sources, according to the needs of the experiments. Each separator (GPS: general purpose; HRS: high resolution) has its own target. Because of the high radiation levels, robots effect the target changes, about 80 times per year. In the standard unit shown in picture _01, the target is the cylindrical object in the front. It contains uranium-carbide kept at a temperature of 2200 deg C, necessary for the isotopes to be able to escape. At either end, one sees the heater current leads, carrying 700 A. The Booster beam, some 3E13 protons per pulse, enters the target from left. The evaporated isotope atoms enter a hot-plasma ion source (the black object behind the target). The whole unit sits at 60 kV potential (pulsed in synchronism with the arrival of the Booster beam) which accelerates the ions (away from the viewer) towards one of the 2 separators.

  15. Radar target detection simulation

    Directory of Open Access Journals (Sweden)

    Tarig Ibrahim Osman

    2014-12-01

    Full Text Available Standard radar detection process requires that the sensor output is compared to a predetermined threshold. The threshold is selected based on a-priori knowledge available and/or certain assumptions. However, any knowledge and/or assumptions become in adequate due to the presence of multiple targets with varying signal return and usually non stationary background. Thus, any predetermined threshold may result in either increased false alarm rate or increased track loss. Even approaches where the threshold is adaptively varied will not perform well in situations when the signal return from the target of interest is too low compared to the average level of the background .Track-before-detect techniques eliminate the need for a detection threshold and provide detecting and tracking targets with lower signal-to-noise ratios than standard methods. However, although trackbefore-detect techniques eliminate the need for detection threshold at sensor's signal processing stage, they often use tuning thresholds at the output of the filtering stage .This paper presents a computerized simulation model for target detection process. Moreover, the proposed model method is based on the target motion models, the output of the detection process can easily be employed for maneuvering target tracking.

  16. Biologic targeting in the treatment of inflammatory bowel diseases [Retraction

    Directory of Open Access Journals (Sweden)

    Bosani M

    2014-01-01

    Full Text Available Bosani M, Ardizzone S, Porro GB. Biologics: Targets and Therapy. 2009;3:77–97.This paper has been retracted after we were made aware that it contains a large amount of reused, and uncited material that was not placed within quotation marks.The following statement has been supplied by Dr Sandro Ardizzone:The review entitled "Biologic targeting in the treatment of inflammatory bowel disease" has been commissioned by this journal and published in 2009 (Matteo Bosani, Sandro Ardizzone, Gabriele Bianchi Porro. Biologics: Targets & Therapy 2009;3:77–97. The paper was written by our young coworker (Dr M Bosani. He has consulted many papers, including our previous reviews published years before. The not perfect knowledge of English language has greatly influenced the writing of the paper itself. So he saved in word file several parts of our previous papers (Ardizzone S, Bianchi Porro G. Inflammatory bowel disease: new insights into pathogenesis and treatment. J Intern Med 2002;252:475–496 – Ardizzone S, Bianchi Porro G. Biologic therapy for inflammatory bowel disease. Drugs 2005:2253–2286, and then transferred to the final paper. He was unaware as we are, of the fact that he could not reuse previously published material in other journals. The reuse of this material was made in good faith.Taking our responsibility for what happened, we intend to apologize for this inconvenience to the Editor (Dr Doris Benbrook and Publisher (Dr Tim Hill. Moreover, for the reasons mentioned above, I consider appropriate to retract the paper itself.This retraction relates to this paper.

  17. Some characteristics of two azoreductase systems in rat liver. Relevance to the activity of 2-[4'-di(2"-bromopropyl)-aminophenylazo]benzoic acid (CB10-252), a compound possessing latent cytotoxic activity

    DEFF Research Database (Denmark)

    1975-01-01

    The system involved in the reduction of 2-[4'-di(2″-bromopropyl)aminophenylazo]benzoic acid (CB10-252), an agent designed for treating primary liver cell cancer, has been demonstrated to be localised mainly in the 108 000 × g supernatant fraction of rat liver homogenate. It is also present in other...... organs particularly in the spleen. DAB-azoreductase as shown previously is present almost entirely in the microsomal fraction and is found in high concentration only in liver. The pH maxima for CB10-252-azoreductase and DAB-azoreductase were 6.2 and 6.9, respectively. Methylred-azoreductase had...

  18. Biogeochemical Controls on Biodegradation of MC252 Oil:Sand Aggregates on a Rapidly Eroding Coastal Headland Beach

    Science.gov (United States)

    Pardue, J.; Elango, V.; Urbano, M.; Lemelle, K.

    2012-12-01

    The research described below was conducted on Fourchon Beach, a coastal headland consisting of nine miles of fairly pristine sandy beaches and dunes, backed by wetlands and tidal channels, located between Belle Pass tidal inlet on the west and Elmer's Island on the east in Lafourche Parish, Louisiana. MC252 oil first arrived in large quantities on Fourchon Beach on or around May 20, 2010. A unique oil form created under these conditions was an aggregate of sand and emulsified oil, typically 0.1-10 cm in diameter, termed small surface residue balls (SSRBs). The work from this project made critical measurements on the factors controlling biodegradability of these SSRB aggregates. SSRB aggregates were sampled across transects perpendicular to the beach from the intertidal to the supratidal. Areas in the supratidal that were sampled initially were set aside for research purposes and not altered by any clean-up activities. Chemical composition of SSRBs was measured including concentrations of n-alkanes, PAHs, hopanes, nutrients (nitrate, nitrite, ammonium and orthophosphate measured on water extracts of SSRBs), and electron acceptor concentrations (O2 microprofiles measured on intact SSRBs and sulfate). Physical characterization of the SSRBs including length and area dimensions, mass, density, porosity, moisture content, and salinity using standard methods. Microbial characterization of SSRBs was also conducted using denaturing gradient gel electrophoresis and sequencing of dominant bands. SSRBs were sampled from various locations across the beach profile deposited by 2 significant tropical events in 2010; Hurricane Alex and TS Bonnie, and one event in 2011, TS Lee. Sampling focused on comparing and contrasting impacts of biogeochemistry on weathering of oil stranded in three beach microenvironments; supratidal surface; subtidal subsurface which is permanently inundated and intertidal subsurface samples which are intermittently inundated. The three types of oil are

  19. The Sinuous Target

    Energy Technology Data Exchange (ETDEWEB)

    Zwaska, R. [Fermilab

    2015-06-01

    We report on the concept for a target material comprised of a multitude of interlaced wires of small dimension. This target material concept is primarily directed at high-power neutrino targets where the thermal shock is large due to small beam sizes and short durations; it also has applications to other high-power targets, particularly where the energy deposition is great or a high surface area is preferred. This approach ameliorates the problem of thermal shock by engineering a material with high strength on the micro-scale, but a very low modulus of elasticity on the meso-scale. The low modulus of elasticity is achieved by constructing the material of spring-like wire segments much smaller than the beam dimension. The intrinsic bends of the wires will allow them to absorb the strain of thermal shock with minimal stress. Furthermore, the interlaced nature of the wires provides containment of any segment that might become loose. We will discuss the progress on studies of analogue materials and fabrication techniques for sinuous target materials.

  20. Targeted assets risk analysis.

    Science.gov (United States)

    Bouwsema, Barry

    2013-01-01

    Risk assessments utilising the consolidated risk assessment process as described by Public Safety Canada and the Centre for Security Science utilise the five threat categories of natural, human accidental, technological, human intentional and chemical, biological, radiological, nuclear or explosive (CBRNE). The categories of human intentional and CBRNE indicate intended actions against specific targets. It is therefore necessary to be able to identify which pieces of critical infrastructure represent the likely targets of individuals with malicious intent. Using the consolidated risk assessment process and the target capabilities list, coupled with the CARVER methodology and a security vulnerability analysis, it is possible to identify these targeted assets and their weaknesses. This process can help emergency managers to identify where resources should be allocated and funding spent. Targeted Assets Risk Analysis (TARA) presents a new opportunity to improve how risk is measured, monitored, managed and minimised through the four phases of emergency management, namely, prevention, preparation, response and recovery. To reduce risk throughout Canada, Defence Research and Development Canada is interested in researching the potential benefits of a comprehensive approach to risk assessment and management. The TARA provides a framework against which potential human intentional threats can be measured and quantified, thereby improving safety for all Canadians. PMID:23615063