WorldWideScience

Sample records for gross alpha particle

  1. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

    Energy Technology Data Exchange (ETDEWEB)

    Zapata-Garcia, D. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Llaurado, M., E-mail: montse.llaurado@ub.edu [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain); Rauret, G. [Laboratori de Radiologia Ambiental (LRA), Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques, 1-11 Planta 3, E-08028 Barcelona (Spain)

    2012-04-15

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO{sub 3}, produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. - Highlights: Black-Right-Pointing-Pointer We study the effect of alpha and beta energies on PSA optimisation. Black-Right-Pointing-Pointer The optimum PSA shifts to higher values as the alpha energy increases. Beta energies do not affect it. Black-Right-Pointing-Pointer We study the effect of pH on the simultaneous determination of gross alpha/beta activities. Black-Right-Pointing-Pointer HNO{sub 3} produces a high amount of misclassification at very low pH. Black-Right-Pointing-Pointer The results improve when HCl is used to adjust the sample to low pH.

  2. The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

    International Nuclear Information System (INIS)

    Zapata-García, D.; Llauradó, M.; Rauret, G.

    2012-01-01

    The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements. The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO 3 , produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH. - Highlights: ► We study the effect of alpha and beta energies on PSA optimisation. ► The optimum PSA shifts to higher values as the alpha energy increases. Beta energies do not affect it. ► We study the effect of pH on the simultaneous determination of gross alpha/beta activities. ► HNO 3 produces a high amount of misclassification at very low pH. ► The results improve when HCl is used to adjust the sample to low pH.

  3. Requirement of radiochemical recovery determination for gross alpha and gross beta estimation in drinking water

    International Nuclear Information System (INIS)

    Raveendran, Nanda; Rao, D.D.; Hegde, A.G.

    2010-01-01

    Presence of radionuclides in drinking water which emits Alpha and Beta particles are the potential sources of internal exposure in drinking water. Gross alpha and gross beta determination in drinking water and packaged drinking water (PDW) as per BIS (Bureau of Indian standards) standards is discussed here. The methods have been tested to account for losses in the radiochemical procedures using radionuclides such as 137 Cs, 90 Sr, 226 Ra, 239 Pu, 243 Am, 232 U. The methods have also been validated in an IAEA proficiency test conducted during 2009. Monitoring of gross alpha and gross beta activity observed in drinking water/packaged drinking water from various states of India were within the limits set by BIS. Average radiochemical recoveries of 84% and 63% were obtained for gross α and gross β respectively. (author)

  4. Measurement of gross alpha and gross beta activity concentrations in human tooth

    International Nuclear Information System (INIS)

    Soeguet, Omer; Aydin, Mehmet Fatih; Kuecuekoender, Erdal; Zorer, Ozlem Selcuk; Dogru, Mahmut

    2010-01-01

    The gross alpha and gross beta activity concentrations were measured in human tooth taken from 3 to 6 age-groups to 40 and over ones. Accumulated teeth samples are investigated in two groups as under and above 18 years. The gross alpha and beta radioactivity of human tooth samples was measured by using a gas-flow proportional counter (PIC-MPC 9604-α/β counter). In tooth samples, for female age-groups, the obtained results show that the mean gross alpha and gross beta activity concentrations varied between 0.534-0.203 and 0.010-0.453 Bq g -1 and the same concentrations for male age-groups varied between 0.009-1.168 and 0.071-0.204 Bq g -1 , respectively.

  5. Gross alpha and gross beta determination in surface and groundwater water by liquid scintillation counting (LSC)

    International Nuclear Information System (INIS)

    Faria, Ligia S.; Moreira, Rubens M.

    2013-01-01

    The present study has used 40 samples of groundwater and surface water collected at four different sites along the period of one year in Brumadinho and Nova Lima, two municipalities in the State of Minas Gerais, Brazil, as part of a more extensive study aiming at determination of the natural radioactivity in the water used for domestic use. These two sites are inside an Environmental Protection Area is located in a region of very intensive iron ore exploration. In addition of mineral resources, the region has a geological characteristic that includes quartzitic conglomerates associated with uranium. Radioactivity levels were determined via liquid scintillation counting (LSC), a fast and high counting efficiency method that can be advantageously employed to determine gross alpha and gross beta activity in liquid samples. Previously to gross alpha and gross beta counting the samples were acidified with concentrated HNO 3 in the field. The technique involved a pre-concentration of the sample to obtain a low detection limit. Specific details of the employed methodology are commented. The results showed that concentrations of gross alpha natural activity and gross beta values ranged from less than the detection limit of the equipment (0.03 Bq.L -1 ) to 0.275 ± 0.05 Bq.L -1 for gross alpha. As regards gross beta, all samples were below the limit of detection. (author)

  6. A Method Validation for Determination of Gross Alpha and Gross Beta in Water Sample Using Low Background Gross Alpha/ Beta Counting System

    International Nuclear Information System (INIS)

    Zal Uyun Wan Mahmood; Norfaizal Mohamed; Nita Salina Abu Bakar

    2016-01-01

    Method validation (MV) for the measurement of gross alpha and gross beta activity in water (drinking, mineral and environmental) samples using Low Background Gross Alpha/ Beta Counting System was performed to characterize precision, accuracy and reliable results. The main objective of this assignment is to ensure that both the instrument and method always good performed and resulting accuracy and reliable results. Generally, almost the results of estimated RSD, z-score and U_s_c_o_r_e were reliable which are recorded as ≤30 %, less than 2 and less than 1.5, respectively. Minimum Detected Activity (MDA) was estimated based on the counting time of 100 minutes and present background counting value of gross alpha (0.01 - 0.35 cpm) and gross beta (0.50 - 2.18 cpm). Estimated Detection Limit (DL) was 0.1 Bq/ L for gross alpha and 0.2 Bq/ L for gross beta and expended uncertainty was relatively small of 9.77 % for gross alpha and 10.57 % for gross beta. Align with that, background counting for gross alpha and gross beta was ranged of 0.01 - 0.35 cpm and 0.50 - 2.18 cpm, respectively. While, sample volume was set at minimum of 500 mL and maximum of 2000 mL. These proven the accuracy and precision result that are generated from developed method/ technique is satisfactory and method is recommended to be used. Therefore, it can be concluded that the MV found no doubtful on the ability of the developed method. The test result showed the method is suitable for all types of water samples which are contained several radionuclides and elements as well as any impurities that interfere the measurement analysis of gross alpha and gross beta. (author)

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  8. Technical Basis for the Use of Alpha Absorption Corrections on RCF Gross Alpha Data

    International Nuclear Information System (INIS)

    Ceffalo, G.M.

    1999-01-01

    This document provides the supporting data and rationale for making absorption corrections to gross alpha data to correct alpha data for loss due to absorption in the sample matrix. For some time there has been concern that the gross alpha data produced by the Environmental Restoration Contractor Radiological Counting Facility, particularly gross alpha analysis on soils, has been biased toward low results, as no correction for self-absorption was applied to the counting data. The process was investigated, and a new methodology for alpha self-absorption has been developed

  9. Innovative procedure for the determination of gross-alpha/gross-beta activities in drinking water

    International Nuclear Information System (INIS)

    Wisser, S.; Frenzel, E.; Dittmer, M.

    2006-01-01

    An alternative sample preparation method for the determination of gross-alpha/beta activity concentrations in drinking water is introduced in this paper. After the freeze-drying of tap water samples, determination by liquid scintillation counting can be applied utilizing alpha/beta separation. It has been shown that there is no adsorption or loss of solid radionuclides during the freeze-drying procedure. However, the samples have to be measured quickly after the preparation since the ingrowth of daughter isotopes negatively effects the measurement. The limits of detection for gross-alpha and gross-beta activity are in the range 25-210 mBq/l, respectively, for a measurement time of only 8-9 h

  10. Gross alpha and beta activities in Tunisian mineral water

    International Nuclear Information System (INIS)

    Hamrouni Benbelgacem, Samar

    2011-01-01

    The quality of natural mineral water is a universal health problem seeing its vital importance. This problem is related to the presence of the radionuclides since this water is coming from underground, during their circulation it dissolves and conveys the radionuclides which are present in the earth's crust. This problem which leads to the contamination of the mineral water urged the World Health Organization to set standards and to recommend the respect of the median values of the activities alpha and beta within the framework of the man protection against this internal exhibition. Concerning the radiological quality of Tunisian mineral water studied in this project, we showed, by using the gross alpha and beta activities counting, that this water is specific to human consumption since their gross alpha and beta activities do not forward any risk on health.

  11. Measurement of Gross Alpha and Gross Beta Radioactivity of River Yobe, North Eastern Nigeria

    International Nuclear Information System (INIS)

    Abba, H. T.; Sadiq, U.; Adeyemo, D. J.

    2013-01-01

    Measurement of the gross alpha and gross beta radioactivity of River Yobe has been carried out. Fifteen samples of the river water were collected from the farming, fishing, domestic/livestock and control areas along the river and were analyzed using desktop alpha/beta (MPC 2000- DP) counting system. The count results show the average alpha activities in farming, fishing, domestic/livestock and control areas are 0.207±0.082, 0.257±0.13, 0.437±0.315 and 0.237±0.10 Bq L -1 , respectively. The average beta activities in the four areas are 0.813±0.122, 0.308±0.0145, 0.563±0.230 and 0.225±0.0096 Bq L -1 , respectively. The overall results show that the alpha and beta activities in the four areas are far below the practical screening level of radioactivity in drinking water of 0.5 Bq L -1 for alpha and 1 Bq L -1 for beta recommended by CEC-FAO and WHO and therefore may not pose any serious detrimental health side-effects to the public users of the river.

  12. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1989-09-01

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

  13. Alpha particle analysis using PEARLS spectrometry

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  14. Influence of crosstalk phenomenon on the measurement of gross alpha and gross beta radioactivity in drinking water

    International Nuclear Information System (INIS)

    Gerilemandahu; Haribala; Xu Xiao; Shen Na; Sai Wenga; Bai Guilin; Wang Chengguo

    2014-01-01

    Objective: To study the influence of crosstalk phenomenon on the measurement of gross radioactivity in drinking water. Methods: The gross activity in different standard materials with different thickness and area was measured using national standard method. Results: There was no obvious change in crosstalk factor with the increase of "2"4"1Am powder amount in the measurement, whereas the larger amount of uranium used might lead to larger crosstalk factor. The different measurement channels resulted in different crosstalk factors. The influence of beta radioactivity on alpha radioactivity measurement was significant. On the contrary, the alpha-to-beta crosstalk factor was negligible. The area of sample plate imposed no significant influence on crosstalk factor. Conclusions: The gross beta activity can be corrected to decrease the influence of alpha radioactivity using powder standard samples, when simultaneous alpha and beta counting mode is applied in measurement grass radioactivity in drinking water. (authors)

  15. A survey of gross alpha and gross beta activity in soil samples in Kinta District, Perak, Malaysia

    International Nuclear Information System (INIS)

    Lee, Siak Kuan; Wagiran, Husin; Ramli, Ahmad Termizi

    2014-01-01

    The objective of this study was to determine the gross alpha and gross beta activity concentrations from the different soil types found in the Kinta District, Perak, Malaysia. A total of 128 soil samples were collected and their dose rates were measured 1 m above the ground. Gross alpha and gross beta activity measurements were carried out using gas flow proportional counter, Tennelec Series 5 LB5500 Automatic Low Background Counting System. The alpha activity concentration ranged from 15 to 9634 Bq kg -1 with a mean value of 1558±121 Bq kg -1 . The beta activity concentration ranged from 142 to 6173 Bq kg -1 with a mean value of 1112±32 Bq kg -1 . High alpha and beta activity concentrations are from the same soil type. The results of the analysis show a strong correlation between the gross alpha activity concentration and dose rate (R = 0.92). The data obtained can be used as a database for each soil type. (authors)

  16. Measurement of gross alpha, gross beta, radon and radium activity concentrations in aqueous samples using liquid scintillation technique

    International Nuclear Information System (INIS)

    Zaini Hamzah; Ahmad Saat; Masitah Alias; Siti Afiqah Abdul Rahman; Mohamed Kasim; Abdul Kadir Ishak

    2011-01-01

    Recently, Malaysia has taken a positive step toward providing a better water quality by introducing more water quality parameters into its Water Quality Standard. With regard to the natural radionuclides that may present in the water, 3 parameters were introduced that is gross alpha, gross beta and radium which need to be measured and cannot exceed 0.1, 1.0 and 1.0 Bq/ L respectively. This study was conducted to develop a more practical method in measuring these parameters in aqueous environmental samples. Besides having a lot of former tin mining areas, some part of Malaysia is located on the granitic rock which also contributes to a certain extent the amount of natural radionuclides such as uranium and thorium. For all we know these two radionuclides are the origin of other radionuclides being produced from their decay series. The State of Kelantan was chosen as the study area, where the water samples were collected from various part of the Kelantan River. 25 liters of samples were collected, acidify to pH 2 and filtered before the analysis. Measurement of these parameters was done using liquid scintillation counter (LSC). The LSC was set up to the optimum discriminator level and counting was done using alpha-beta mode. The results show that gross alpha and beta can be measured using scintillation cocktail and radium and radon using extraction method. The results for gross alpha, gross beta, 222 Ra and 226 Ra are 0.39-6.42, 0.66-16.18, 0.40-4.65 and 0.05-0.56 Bq/ L. MDA for gross alpha, gross beta and radium is 0.03, 0.08 and 0.00035 Bq/ L respectively. (Author)

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

    International Nuclear Information System (INIS)

    2007-01-01

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

  18. Determination of gross alpha and gross beta in soil around repository facility at Bukit Kledang, Perak, Malaysia

    Science.gov (United States)

    Adziz, Mohd Izwan Abdul; Siong, Khoo Kok

    2018-04-01

    Recently, the Long Term Storage Facility (LTSF) in Bukit Kledang, Perak, Malaysia, has been upgraded to repository facility upon the completion of decontamination and decommissioning (D&D) process. Thorium waste and contaminated material that may contain some minor amounts of thorium hydroxide were disposed in this facility. This study is conducted to determine the concentrations of gross alpha and gross beta radioactivities in soil samples collected around the repository facility. A total of 12 soil samples were collected consisting 10 samples from around the facility and 2 samples from selected residential area near the facility. In addition, the respective dose rates were measured 5 cm and 1 m above the ground by using survey meter with Geiger Muller (GM) detector and Sodium Iodide (NaI) detector. Soil samples were collected using hand auger and then were taken back to the laboratory for further analysis. Samples were cleaned, dried, pulverized and sieved prior to analysis. Gross alpha and gross beta activity measurements were carried out using gas flow proportional counter, Canberra Series 5 XLB - Automatic Low Background Alpha and Beta Counting System. The obtained results show that, the gross alpha and gross beta activity concentration ranged from 1.55 to 5.34 Bq/g with a mean value of 3.47 ± 0.09 Bq/g and 1.64 to 5.78 Bq/g with a mean value of 3.49 ± 0.09 Bq/g, respectively. These results can be used as an additional data to represent terrestrial radioactivity baseline data for Malaysia environment. This estimation will also serve as baseline for detection of any future related activities of contamination especially around the repository facility area.

  19. Source of gross-alpha radioactivity anomalies in recharge wells, central Florida phosphate district. Final report

    International Nuclear Information System (INIS)

    Oural, C.R.; Brooker, H.R.; Upchurch, S.B.

    1986-01-01

    The central Florida phosphate industry utilizes recharge wells to mitigate withdrawals of water from the Florida aquifer and to dewater the surficial aquifer prior to mining. From a water-management point of view, these wells are efficient and serve a vital function. Recent monitoring of the radiation environment in these wells, however, casts doubts on the safety of the wells. While most of the wells conform to state and federal standards for radium, gross-alpha radiation frequently exceeds standards. The purpose of the study was to determine the radionuclide(s) responsible for the high gross-alpha radiation and to identify a method for sampling of the recharge wells that would standardize data across the phosphate district. It was found that excess gross alpha is primarily due to polonium-210. Since gross alpha and polonium-210 measurements are quite sensitive to methods of sample collections, preservation and analyses, standard procedures for sample processing are presented in the report

  20. Measurement of gross alpha - activity in some thermal water sources in Yugoslavia by SSNTDs

    International Nuclear Information System (INIS)

    Benderac, R.; Ristic, D.; Antanasijevic, R.; Vukovic, J.

    1991-01-01

    The possible application of the CN-BDH (type 1) nitrocellulose detector synthesized in laboratory conditions, and also the CR-39 detector, to the measurement of the gross alpha-activity of geothermal and mineral water has been investigated. (author)

  1. Measurement of gross alpha and beta in air filter samples by using liquid scintillation counter

    International Nuclear Information System (INIS)

    Sudheendran, V.; Baburajan, A.; Gaikwad, R.H.; Ravi, P.M.; Tripathi, R.M.

    2015-01-01

    The determination of gross alpha and gross beta in particulate air filter samples was carried out by alpha, beta discrimination method using Liquid Scintillation Analyzer by setting the PSA value at 55 for 5 ml 0.1 HCl plus 15 ml of Ultima Gold AB cocktail by using 241 Am and 90 Sr/ 90 Y sources. The standardized method was compared with the gross alpha and gross beta activity determined by conventional method of direct counting with end window G.M. counter and ZnS (Ag). The minimum detectable activity of LSA method was found to be 9.3 mBq and 17.7 mBq for gross alpha and gross beta respectively for 6000 sec compared to the conventional method of 9.8 mBq and 189 mBq respectively at the same counting time. The result of analysis by both method indicate that the alpha, beta discrimination set up of LSA method is highly effective in the determination of low level alpha, beta activity in air filter samples. (author)

  2. Design of a Quality Control Program for the Measurement of Gross Alpha and Gross Beta Activities (LMPR-CIEMAT)

    International Nuclear Information System (INIS)

    Alvarez, A.; Yague, L.; Gasco, C.; Navarro, N.; Higueras, E.; Noguerales, C.

    2010-01-01

    In accordance with international standards, general requirements for testing laboratories have to include a quality system for planning, implementing, and assessing the work performed by the organization and for carrying out required quality assurance and quality control. The purpose of internal laboratory quality control is to monitor performance, identify problems, and initiate corrective actions. This report describes the internal quality control to monitor the gross alpha and beta activities determination. Identification of specific performance indicators, the principles that govern their use and statistical means of evaluation are explained. Finally, calculation of alpha and beta specific activities, uncertainties and detection limits are performed. (Author) 10 refs.

  3. Uranium, thorium, gross alpha and gross beta assessment in fountain waters in towns of the Iron Quadrangle, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Claudia A.; Palmieri, Helena E.L.; Menezes, Maria Angela de B.C.; Chaves, Renata D.A.; Dalmazio, Ilza, E-mail: cferreiraquimica@yahoo.com.br, E-mail: help@cdtn.br, E-mail: menezes@cdtn.br, E-mail: rda@cdtn.br, E-mail: id@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The Iron Quadrangle region is known worldwide for its diversity, both ores and rock types, which record a long and important period of Earth's history. For thousands of years erosive processes have exposed ancient rocks, Archean and Proterozoic, in this region. The concentration of uranium, thorium, gross alpha and gross beta activities has been assessed in 34 fountains water samples collected from different towns in the Iron Quadrangle. The results obtained were compared to values established by CONAMA nº 396/2008 and Decree nº 2914/2011 by the Ministry of Health. For Th in water consumption there is no value established in the Brazilian legislation and the concentrations in all samples were lower than 0.01 μg L{sup -1}. For uranium, the values ranged from less than 0.002 to 0.61 μg L{sup -1}, and all results were lower than the value allowed of 15 μg L{sup -1} and 30 μg L{sup -1} established by the legislations above, respectively. The results for the radiation levels of gross alpha and gross beta activity in some fountains waters were slightly above the limits (0.5 Bq L{sup -1} and 1.0 Bq L{sup -1}) established by CONAMA nº 396/2008 and Decreet nº 2914/2011, respectively. (author)

  4. Uranium, thorium, gross alpha and gross beta assessment in fountain waters in towns of the Iron Quadrangle, Brazil

    International Nuclear Information System (INIS)

    Ferreira, Claudia A.; Palmieri, Helena E.L.; Menezes, Maria Angela de B.C.; Chaves, Renata D.A.; Dalmazio, Ilza

    2013-01-01

    The Iron Quadrangle region is known worldwide for its diversity, both ores and rock types, which record a long and important period of Earth's history. For thousands of years erosive processes have exposed ancient rocks, Archean and Proterozoic, in this region. The concentration of uranium, thorium, gross alpha and gross beta activities has been assessed in 34 fountains water samples collected from different towns in the Iron Quadrangle. The results obtained were compared to values established by CONAMA nº 396/2008 and Decree nº 2914/2011 by the Ministry of Health. For Th in water consumption there is no value established in the Brazilian legislation and the concentrations in all samples were lower than 0.01 μg L -1 . For uranium, the values ranged from less than 0.002 to 0.61 μg L -1 , and all results were lower than the value allowed of 15 μg L -1 and 30 μg L -1 established by the legislations above, respectively. The results for the radiation levels of gross alpha and gross beta activity in some fountains waters were slightly above the limits (0.5 Bq L -1 and 1.0 Bq L -1 ) established by CONAMA nº 396/2008 and Decreet nº 2914/2011, respectively. (author)

  5. The calculation of the detection efficiency in the calibration of gross alpha-beta systems

    International Nuclear Information System (INIS)

    Marian Romeo Calin; Ileana Radulescu; Alexandru Erminiu Druker

    2013-01-01

    This paper presents a method for efficiency calibration of a measuring alpha-beta system PROTEAN ORTEC, MPC-2000-DP, using standard radioactive sources. The system is used to measure gross alpha-beta activity concentrations in environmental samples. The calculated efficiencies of detection were subsequently introduced in the system for two working geometries: measuring geometry-gross alpha-beta ε α g = 31,37 ± 0.25 (%)-the alpha efficiency and ε β g 44.94 ± 0.69 (%)-the beta efficiency, where the spillover factor is X talk g = 25.59 ± 0.50 (%) and measuring geometry up alpha-beta ε α u 36.23 ± 0.29 (%)-the alpha efficiency and ε β u = 48.53 ± 0.74 (%)-the beta efficiency, where the spillover factor is X talk u 31.08 ± 0.60 (%). (author)

  6. Alpha particle studies during JET DT experiments

    International Nuclear Information System (INIS)

    1999-01-01

    The 1997 DT experiment (DTE1) at the Joint European Torus included studies of the behaviour of alpha particles in high temperature plasmas. Clear alpha particle heating was observed in a series of otherwise similar 10MW hot-ion H-modes by scanning the DT mixture from 0%T to 93%T. Maxima in central temperature and energy content were obtained which corresponded with the maximum in fusion yield. Alfven Eigenmodes (AEs) have been detected in JET, driven by NBI or ICRH fast ions. However, in agreement with theory, no AE activity was observed in DT plasmas which could be attributed to alpha particle drive, except in the afterglow of some Optimised Shear pulses. Ion Cyclotron Emission (ICE) was detected at harmonics of the alpha particle cyclotron frequency at the outer edge of the plasma. The ICE is interpreted as being close to magnetoacoustic cyclotron instability, driven by inverted alpha distributions at the plasma edge. The high-energy neutral particle spectra showed features, which are ascribed to a mixture of alphas, neutralised by helium-like impurities, and deuterons, born from elastic collisions with alpha particles and neutralised by hydrogen-like impurities. The results of all these studies are consistent with classical alpha particle trapping and slowing-down. Future DT experiments will aim to increase alpha particle pressure, so interactions with plasma instabilities can be studied. The measurement of knock-on neutral triton spectra offers a clean way to determine confined alpha densities in these future experiments. (author)

  7. Alpha particle studies during JET DT experiments

    International Nuclear Information System (INIS)

    2001-01-01

    The 1997 DT experiment (DTE1) at the Joint European Torus included studies of the behaviour of alpha particles in high temperature plasmas. Clear alpha particle heating was observed in a series of otherwise similar 10MW hot-ion H-modes by scanning the DT mixture from 0%T to 93%T. Maxima in central temperature and energy content were obtained which corresponded with the maximum in fusion yield. Alfven Eigenmodes (AEs) have been detected in JET, driven by NBI or ICRH fast ions. However, in agreement with theory, no AE activity was observed in DT plasmas which could be attributed to alpha particle drive, except in the afterglow of some Optimised Shear pulses. Ion Cyclotron Emission (ICE) was detected at harmonics of the alpha particle cyclotron frequency at the outer edge of the plasma. The ICE is interpreted as being close to magnetoacoustic cyclotron instability, driven by inverted alpha distributions at the plasma edge. The high-energy neutral particle spectra showed features, which are ascribed to a mixture of alphas, neutralised by helium-like impurities, and deuterons, born from elastic collisions with alpha particles and neutralised by hydrogen-like impurities. The results of all these studies are consistent with classical alpha particle trapping and slowing-down. Future DT experiments will aim to increase alpha particle pressure, so interactions with plasma instabilities can be studied. The measurement of knock-on neutral triton spectra offers a clean way to determine confined alpha densities in these future experiments. (author)

  8. Gross alpha and beta activities in drinking water from Goias State, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Mingote, Raquel M. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Belo Horizonte, MG (Brazil); Nogueira, Regina A.; Costa, Heliana F. da, E-mail: raquel.mingote@cdtn.br, E-mail: rnogueira@cnen.gov.br, E-mail: heliana@cnen.gov.br [Centro Regional de Ciencias Nucleares do Centro-Oeste (CRCN-CO/CNEN), Abadia de Goias, GO (Brazil). Parque Estadual Telma Ortegal

    2017-07-01

    Detection of gross alpha and beta radioactivity is important for a quick surveying of both natural and anthropogenic radioactivity in water. Furthermore, gross alpha and gross beta parameters are included in Brazilian legislation on quality of drinking water. In this work, a low background liquid scintillation spectrometer was used to simultaneously determine gross alpha and gross beta in samples of the public water supplies in the state of Goias, Brazil, during 2010-2015. Sample preparation involved evaporation to concentrate the sample ten-fold. The results indicate that the water meets the radioactivity standards required by the regulations MS 2914/2011 of the Brazilian Department of Health. Concerning the high level of censored observations, a statistical treatment of data was conducted by using analysis methods of censored data to provide a reference value of the gross alpha and beta radioactivity in drinking water from the state of Goias. The estimated typical activities are very low, 0.030 Bq•L{sup -1} and 0.058 Bq•L{sup -1}, respectively. (author)

  9. Gross alpha radioactivity of drinking water in Venezuela

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  10. Determination of self absorption correction factor (SAF) for gross alpha measurement in water samples by BIS method

    International Nuclear Information System (INIS)

    Raveendran, Nanda; Baburajan, A.; Ravi, P.M.

    2018-01-01

    The laboratories accredited by AERB undertake the measurement of gross alpha and gross beta in packaged drinking water from manufactures across the country and analyze as per the procedure of Bureau of Indian standards. The accurate measurements of gross alpha in the drinking water sample is a challenge due to the self absorption of alpha particle from varying precipitate (Fe(OH) 3 +BaSO 4 ) thickness and total dissolved solids (TDS). This paper deals with a study on tracer recovery generation and self absorption correction factor (SAF). ESL, Tarapur has participated in an inter-laboratory comparison exercise conducted by IDS, RSSD, BARC as per the recommendation of AERB for the accredited laboratories. The thickness of the precipitate is an important aspect which affected the counting process. The activity was reported after conducting multiple experiments with uranium tracer recovery and precipitate thickness. Later on to make our efforts simplified, an average tracer recovery and Self Absorption correction Factor (SAF) was derived by the present experiment and the same was used for the re-calculation of activity from the count rate reported earlier

  11. Estimation of low level gross alpha activities in the radioactive effluent using liquid scintillation counting technique

    International Nuclear Information System (INIS)

    Bhade, Sonali P.D.; Johnson, Bella E.; Singh, Sanjay; Babu, D.A.R.

    2012-01-01

    A technique has been developed for simultaneous measurement of gross alpha and gross beta activity concentration in low level liquid effluent samples in presence of higher activity concentrations of tritium. For this purpose, alpha beta discriminating Pulse Shape Analysis Liquid Scintillation Counting (LSC) technique was used. Main advantages of this technique are easy sample preparation, rapid measurement and higher sensitivity. The calibration methodology for Quantulus1220 LSC based on PSA technique using 241 Am and 90 Sr/ 90 Y as alpha and beta standards respectively was described in detail. LSC technique was validated by measuring alpha and beta activity concentrations in test samples with known amount of 241 Am and 90 Sr/ 90 Y activities spiked in distilled water. The results obtained by LSC technique were compared with conventional planchet counting methods such as ZnS(Ag) and end window GM detectors. The gross alpha and gross beta activity concentrations in spiked samples, obtained by LSC technique were found to be within ±5% of the reference values. (author)

  12. The determination of the national background radioactivity of gross alpha and gross beta in water samples at the PUSPATI site and its neutrons

    International Nuclear Information System (INIS)

    Rahman, M.T.A.

    1983-01-01

    The determination of the natural background radioactivity in water samples has been made at the PUSPATI site and its environs. The study was performed in January 1981 until June 1981. Samples of river, rain and tap water are periodically collected and analyzed in order to determine gross alpha and gross beta activity. In general, the total radioactivity of water is considerably low. The mean concentration of gross alpha in river water and tap water samples are 1.2 +- 0.1 and 0.2 +- 0.1 pCi/ respectively. The level of gross alpha in rain water is however, below the background rate of the detector. The mean concentration of gross beta in river water, tap water and rain water samples are 4.2 +- 0.6, 1.6 +- 0.3, and 1.9 +- 0.3 pCi/ respectively. (author)

  13. 210Po in Nevada groundwater and its relation to gross alpha radioactivity

    Science.gov (United States)

    Seiler, R.L.

    2011-01-01

    Polonium-210 (210Po) is a highly toxic alpha emitter that is rarely found in groundwater at activities exceeding 1 pCi/L. 210Po activities in 63 domestic and public-supply wells in Lahontan Valley in Churchill County in northern Nevada, United States, ranged from 0.01 ± 0.005 to 178 ± 16 pCi/L with a median activity of 2.88 pCi/L. Wells with high 210Po activities had low dissolved oxygen concentrations (less than 0.1 mg/L) and commonly had pH greater than 9. Lead-210 activities are low and aqueous 210Po is unsupported by 210Pb, indicating that the 210Po is mobilized from aquifer sediments. The only significant contributors to alpha particle activity in Lahontan Valley groundwater are 234/238U, 222Rn, and 210Po. Radon-222 activities were below 1000 pCi/L and were uncorrelated with 210Po activity. The only applicable drinking water standard for 210Po in the United States is the adjusted gross alpha radioactivity (GAR) standard of 15 pCi/L. 210Po was not volatile in a Nevada well, but volatile 210Po has been reported in a Florida well. Additional information on the volatility of 210Po is needed because GAR is an inappropriate method to screen for volatile radionuclides. About 25% of the samples had 210Po activities that exceed the level associated with a lifetime total cancer risk of 1× 10−4 (1.1 pCi/L) without exceeding the GAR standard. In cases where the 72-h GAR exceeds the uranium activity by more than 5 to 10 pCi/L, an analysis to rule out the presence of 210Po may be justified to protect human health even though the maximum contaminant level for adjusted GAR is not exceeded.

  14. Monitoring gross alpha and beta activity in liquids by using ZnS(Ag) scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Stevanato, L.; Cester, D.; Filippi, D.; Lunardon, M.; Mistura, G.; Moretto, S.; Viesti, G. [Department of Physics and Astronomy ' Galileo Galilei' , University of Padova, (Italy); Badocco, D.; Pastore, P.; Romanini, F. [Department of Chemical Sciences, University of Padova, (Italy)

    2015-07-01

    In this work the possibility of monitoring gross alpha and beta activity in liquids using EJ-444 was investigated. Specific tests were carried out to determine the change of the detector properties in water tests. Possible protecting coating is also proposed and tested. Alpha/beta real-time monitoring in liquids is a goal of the EU project TAWARA{sub R}TM. (authors)

  15. Effects of alpha particles on zebrafish embryos

    International Nuclear Information System (INIS)

    Yum, E.H.W.; Choi, V.W.Y.; Yu, K.N.; Li, V.W.T.; Cheng, S.H.

    2008-01-01

    Full text: Ionizing radiation such as X-ray and alpha particles can damage cellular macromolecules, which can lead to DNA single- and double-strand breaks. In the present work, we studied the effects of alpha particles on dechorionated zebrafish embryos. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 μm were prepared from commercially available PADC films (with thickness of 100 μm) by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 1.25 hours post fertilization (hpf) with various absorbed dose. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed on the embryos at different time stages after irradiation. Marked apoptosis was detected only in embryos at earlier time stages. The results showed that DNA double-strand break during zebrafish embryogenesis can be induced by alpha-particle irradiation, which suggests that zebrafish is a potential model for assessing the effects of alpha-particle radiation

  16. Stochastic interaction between TAE and alpha particles

    International Nuclear Information System (INIS)

    Krlin, L.; Pavlo, P.; Malijevsky, I.

    1996-01-01

    The interaction of toroidicity-induced Alfven eigenmodes with thermonuclear alpha particles in the intrinsic stochasticity regime was investigated based on the numerical integration of the equation of motion of alpha particles in the tokamak. The first results obtained for the ITER parameters and moderate wave amplitudes indicate that the stochasticity is highest in the trapped/passing boundary region, where the alpha particles jump stochastically between the two regimes with an appreciable radial excursion (about 0.5 m amplitudes). A similar chaotic behavior was also found for substantially lower energies (about 350 keV). 7 figs., 15 refs

  17. Alpha particle radiography of small insects

    International Nuclear Information System (INIS)

    Chingshen Su

    1993-01-01

    Radiographies of ants, mosquitoes, cockroaches and small bugs have been done with a radioisotope 244 Cm alpha source. Energy of alpha particles was varied by attenuating the 5.81 MeV alpha particles with adjustable air spacings from the source to the sample. The LR-115 was used to register radiographs. The image of the insect registered on the LR-115 was etched out in a 2.5 N NaOH solution at 52 o C for certain minutes, depending on various irradiation conditions for the insects. For larger insects, a scanning device for the alpha particle irradiation has been fabricated to take the radiograph of whole body of the insect, and the scanning period can be selected to give desired irradiation dosage. A CCDTV camera system connected to a microscope interfaced to an IBM/AT computer is used to register the microscopic image of the radiograph and to print it out with a video copy processor. (Author)

  18. Spreadsheet design and validation for characteristic limits determination in gross alpha and beta measurement

    International Nuclear Information System (INIS)

    Prado, Rodrigo G.P. do; Dalmazio, Ilza

    2013-01-01

    The identification and detection of ionizing radiation are essential requisites of radiation protection. Gross alpha and beta measurements are widely applied as a screening method in radiological characterization, environmental monitoring and industrial applications. As in any other analytical technique, test performance depends on the quality of instrumental measurements and reliability of calculations. Characteristic limits refer to three specific statistics, namely, decision threshold, detection limit and confidence interval, which are fundamental to ensuring the quality of determinations. This work describes a way to calculate characteristic limits for measurements of gross alpha and beta activity applying spreadsheets. The approach used for determination of decision threshold, detection limit and limits of the confidence interval, the mathematical expressions of measurands and uncertainty followed standards guidelines. A succinct overview of this approach and examples are presented and spreadsheets were validated using specific software. Furthermore, these spreadsheets could be used as tool to instruct beginner users of methods for ionizing radiation measurements. (author)

  19. Alpha particles detection in nitrocellulose

    International Nuclear Information System (INIS)

    Romero C, M.

    1976-01-01

    The method for the manufacturing of the detection films follows these steps: preparation of the mass which includes nitrocellulose in the form of cotton as raw material ethyl acetate, cellosolve acetate, isopropyl and butyl alcohols as solvents and dioctyl phtalate as plasticiser; dilution of the paste; pouring of the diluted mass; and drying of the detection films. The results obtained experimentally are: The determination of the development times of the different thicknesses of the manufactured films. Response linearity of the detectors, variation of the number of tracks according to the distance of the source to the detector. Sizes of the diameter of the tracks depending of the distance detector-alpha emmission source. As a conclusion we can say the the nitrocellulose detectors are specific for alpha radiation; the more effective thicknesses in uranium prospecting works were those of 60 microns, since for the laboratory works the thicknesses of 30 to 40 microns were the ideal; the development technique of the detection films is simple and cheap and can be realized even in another place than the laboratory; this way of the manufacturing of nitrocellulose detection film sensitive to alpha nuclear radiation is open to future research. (author)

  20. Measurement of Gross Alpha and Beta Emission Rates from Ceramic Tiles

    International Nuclear Information System (INIS)

    Wudthicharoonpun, Piyasak; Chankow, Nares

    2007-08-01

    Full text: Ceramic tiles normally used to cover floors and walls contain naturally occurring radioactive elements i.e. potassium-40, uranium, thorium and their daughters from raw materials. Thus, radioactivity was dependent upon source of raw materials and the amount used. The objective of this research was to measure gross alpha and beta emission rates to be used as a database for safety assessment and for selection of rooms to measure radioactive radon-222 gas

  1. Gross alpha/beta analyses in water by liquid scintillation counting

    International Nuclear Information System (INIS)

    Wong, C.T.; Lawrence Livermore National Laboratory, CA; Soliman, V.M.; Perera, S.K.

    2005-01-01

    The standard procedure for analyzing gross alpha and gross beta in water is evaporation of the sample and radioactivity determination of the resultant solids by proportional counting. This technique lacks precision, and lacks sensitivity for samples with high total dissolved solids. Additionally, the analytical results are dependent on the choice of radionuclide calibration standard and the sample matrix. Direct analysis by liquid scintillation counting has the advantages of high counting efficiencies and minimal sample preparation time. However, due to the small sample aliquants used for analysis, long count times are necessary to reach required detection limits. The procedure proposed consists of evaporating a sample aliquant to dryness, dissolving the resultant solids in a small volume of dilute acid, followed by liquid scintillation counting to determine radioactivity. This procedure can handle sample aliquants containing up to 500 mg of dissolved solids. Various acids, scintillation cocktail mixtures, instrument discriminator settings, and regions of interest (ROI) were evaluated to determine optimum counting conditions. Precision is improved and matrix effects are reduced as compared to proportional counting. Tests indicate that this is a viable alternative to proportional counting for gross alpha and gross beta analyses of water samples. (author)

  2. The Determination of Gross Alpha And Beta Activity of Drinking Water in Turkey

    International Nuclear Information System (INIS)

    Dilaver, A.T.; Cifter, C.; Altay, T.

    2002-01-01

    Man and his environment must be protected from the adverse effects of pesticides, radiation, noise and other forms of pollutions. Radioactive materials occur naturally in the environment (for example uranium, thorium and potassium). Same radioactive compounds arise from human activities (for example from medical or industrial uses of radioactivity). Drinking water should be safe to use and aesthetically pleasing. World Health Organisation (WHO) and Turkish Standards (TSE) have established maximum contaminant levels for gross alpha and gross beta. The purpose of these study is to determine the level of gross alpha and gross beta activities of samples collected from the different Regional Directories of The State Hydraulic Works (DSI)). After that compare the results versus permissible values of World Health Organisation and Turkish Standards. Collected samples from 14 Regional Directories of The State Hydraulic Works (DSI), have completed. All the analyses results suitable for WHO and TSE. We will give all the research our final report after completed the other Regional Directories' s analyses

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  4. Liquid scintillation alpha particle spectrometry. Progress report

    International Nuclear Information System (INIS)

    Bell, L.L.; Hakooz, S.A.; Johnson, L.O.; Nieschmidt, E.B.; Meikrantz, D.H.

    1979-12-01

    Objective to develop a technique whereby Pu may be put into solution, extracted by solvent extraction into a suitable extractive scintillant and subsequently counted. Presented here are results of attempts to separate beta and alpha activities through pulse shape discrimination. A qualitative discussion is given which yields alpha particle peak widths, resolution and response. The detection efficiency for alpha particles in a liquid scintillant is 100%. Present detection sensitivities of the equipment being used are: 4.5 x 10 -6 μCi (100 s), 1.2 x 10 -6 μCi (1000 s), and 4.0 x 10 -7 μCi (10,000 s) at the 3 sigma level. The detectability of a particular alpha-emitting species is strongly dependent upon the population of other species. The ability to discriminate depends upon the system resolution. 14 figures, 2 tables

  5. Alpha particles spectrometer with photodiode PIN

    International Nuclear Information System (INIS)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R.; Ramirez G, J.

    2009-10-01

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  6. Alternating current long range alpha particle detector

    International Nuclear Information System (INIS)

    MacArthur, D.W.; McAtee, J.L.

    1993-01-01

    An alpha particle detector, utilizing alternating currents, which is capable of detecting alpha particles from distinct sources. The use of alternating currents allows use of simpler ac circuits which, in turn, are not susceptible to dc error components. It also allows the benefit of gas gain, if desired. In the invention, a voltage source creates an electric field between two conductive grids, and between the grids and a conductive enclosure. Air containing air ions created by collision with alpha particles is drawn into the enclosure and detected. In some embodiments, the air flow into the enclosure is interrupted, creating an alternating flow of ions. In another embodiment, a modulated voltage is applied to the grid, also modulating the detection of ions

  7. Preparation and validation of gross alpha/beta samples used in EML's quality assessment program

    International Nuclear Information System (INIS)

    Scarpitta, S.C.

    1997-10-01

    A set of water and filter samples have been incorporated into the existing Environmental Measurements Laboratory's (EML) Quality Assessment Program (QAP) for gross alpha/beta determinations by participating DOE laboratories. The participating laboratories are evaluated by comparing their results with the EML value. The preferred EML method for measuring water and filter samples, described in this report, uses gas flow proportional counters with 2 in. detectors. Procedures for sample preparation, quality control and instrument calibration are presented. Liquid scintillation (LS) counting is an alternative technique that is suitable for quantifying both the alpha ( 241 Am, 230 Th and 238 Pu) and beta ( 90 Sr/ 90 Y) activity concentrations in the solutions used to prepare the QAP water and air filter samples. Three LS counting techniques (Cerenkov, dual dpm and full spectrum analysis) are compared. These techniques may be used to validate the activity concentrations of each component in the alpha/beta solution before the QAP samples are actually prepared

  8. Alpha particle effects on MHD ballooning

    International Nuclear Information System (INIS)

    1991-01-01

    During the period, as the first step towards the goal of detail understanding of the effects of alpha particle on MHD Ballooning Modes, a new numerical approach to investigate the stability of low-frequency fluctuations in high temperature tokamaks was developed by solving the gyrokinetic equations for the ion and electron directly as an initial value problem. The advantage of this approach is the inclusion of many important kinetic features of the problem without approximations and computationally more economical than particle-pushing simulation. The ion-temperature-gradient-mode was investigated to benchmark this new simulation technique. Previous results in literature were recovered. Both the adiabatic electron model and the full drift-kinetic electron model are studied. Numerical result shows that the full drift-kinetic electron model is more unstable. The development of subcycling technique to handle the fast electron bounce time is particularly significant to apply this new approach to the alpha particle problem since alpha particle bounce frequency is also significantly higher than the mode frequency. This new numerical technique will be the basis of future study of the microstability in high temperature tokamaks with alpha particles (or any energetic species). 15 refs., 13 figs

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  10. Measurement of gross alpha - activity in some thermal water sources in Yugoslavia by SSNTDs. [Solid state nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benderac, R.; Ristic, D. (Inst. of Security, Belgrade (Yugoslavia)); Antanasijevic, R.; Vukovic, J. (Belgrade Univ. (Yugoslavia))

    1991-01-01

    The possible application of the CN-BDH (type 1) nitrocellulose detector synthesized in laboratory conditions, and also the CR-39 detector, to the measurement of the gross alpha-activity of geothermal and mineral water has been investigated. (author).

  11. Alpha particles, are they really a problem

    International Nuclear Information System (INIS)

    Waddell, J.M.

    1980-01-01

    Soft errors are nonrepetitive errors generated in systems employing dynamic Random Access Memories, and specially by alpha particles emitted by uranium on thorium occurring as impurities in the casings. Special attention was given to this problem by ITT Semiconductors, a 16 K dynamic range being considered. The results of these studies are given in this article [fr

  12. Laboratory system for alpha particle spectroscopy

    International Nuclear Information System (INIS)

    Dean, J.R.; Chiu, N.W.

    1987-03-01

    An automated alpha particle spectroscopy system has beeen designed and fabricated. It consists of two major components, the automatic sample changer and the controller/data acquisition unit. It is capable of unattended analysis of ten samples for up to 65,000 seconds per sample

  13. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies...

  14. Radon Progenies as a Source of Gross Alpha-beta Activities in Drinking Water in Vinaninkarena, Antsirabe-Madagascar

    International Nuclear Information System (INIS)

    Raoelina Andriambololona; Rabesiranana, N.; Rasolonirina, M.; Rakotomanga, H.

    2004-01-01

    The village of Vinaninkarena, Antsirabe, Madagascar is located in a high radioactivity area. With the aim of assessing the health impact of radioactivity pollution, a survey was conducted around an abandoned radium mining. Waters from 24 sampling points, including 5 wells and 13 springs were sampled. The water radioactivity was measured using a portable Triathler LSC, model 425-034 from Hidex Turku. Each sample is counted more than 3 times: less than 2h after sampling, 4h to few days and more than 3 weeks after when 226 Ra attains equilibrium with 222 Rn and its short-lived daughters. Combination of water non miscible, radon extractive LS cocktail and water miscible one is used to reveal contribution of radium, radon and its short lived progenies to the gross alpha-beta activities. Maximum activity values found are : 3.6±0.3 Bq.L -1 for 226 Ra, 554±9 Bq.L -1 for the excess of radon, and 408±8 Bq.L -1 for the excess of radon progenies. Based on these data, a daily consumption of 2 L of these waters by a standard person would produce an annual 226 Ra ingestion well above the annual intake limit for 226 Ra. Moreover, the increasing gross alpha-beta activity resulting from radon progenies raises the issue of health effects. The potential for rapid spring-to-mouth delivery, which is frequent in rural area, may expose the water consumer to the short-lived alpha particle emitters.

  15. Determining the level of gross alpha and beta radioactivity of water from Marilao river using liquid scintillation counter

    International Nuclear Information System (INIS)

    Cruz, J.; Magtaka, J.; Balisi, R.; Castaneda, Soledad; De Vero, J.

    2009-01-01

    This study aims to determine the level of gross alpha- and beta- radioactivity present in the Marilao River. Liquid Scintillation Counter was used to detect samples radioactivity. Water samples were taken along the different spots of Marilao River. The results showed that the radioactivity are below the Philippine National Standard for Drinking Water (PNSDW) which is 0.1 Bq/L for gross alpha activity and 1.0 Bq/L for gross beta activity set by the Dept. of Health. Hence water samples from Marilao River, is safe in terms of the level of radioactivity levels.(author)

  16. Computer simulation of backscattered alpha particles

    International Nuclear Information System (INIS)

    Sanchez, A. Martin; Bland, C.J.; Timon, A. Fernandez

    2000-01-01

    Alpha-particle spectrometry forms an important aspect of radionuclide metrology. Accurate measurements require corrections to be made for factors such as self-absorption within the source and backscattering from the backing material. The theory of the latter phenomenon has only received limited attention. Furthermore the experimental verification of these theoretical results requires adequate counting statistics for a variety of sources with different activities. These problems could be resolved by computer simulations of the various interactions which occur as alpha-particles move through different materials. The pioneering work of Ziegler and his coworkers over several years, has provided the sophisticated software (SRIM) which has enabled us to obtain the results presented here. These results are compared with theoretical and experimental values obtained previously

  17. Intercomparison of alpha particle spectrometry software packages

    International Nuclear Information System (INIS)

    1999-08-01

    Software has reached an important level as the 'logical controller' at different levels, from a single instrument to an entire computer-controlled experiment. This is also the case for software packages in nuclear instruments and experiments. In particular, because of the range of applications of alpha-particle spectrometry, software packages in this field are often used. It is the aim of this intercomparison to test and describe the abilities of four such software packages. The main objectives of the intercomparison were the ability of the programs to determine the peak areas and the peak area uncertainties, and the statistical control and stability of reported results. In this report, the task, methods and results of the intercomparison are presented in order to asist the potential users of such software and to stimulate the development of even better alpha-particle spectrum analysis software

  18. Single particle level scheme for alpha decay

    International Nuclear Information System (INIS)

    Mirea, M.

    1998-01-01

    The fine structure phenomenon in alpha decay was evidenced by Rosenblum. In this process the kinetic energy of the emitted particle has several determined values related to the structure of the parent and the daughter nucleus. The probability to find the daughter in a low lying state was considered strongly dependent on the spectroscopic factor defined as the square of overlap between the wave function of the parent in the ground state and the wave functions of the specific excited states of the daughter. This treatment provides a qualitative agreement with the experimental results if the variations of the penetrability between different excited states are neglected. Based on single particle structure during fission, a new formalism explained quantitatively the fine structure of the cluster decay. It was suggested that this formalism can be applied also to alpha decay. For this purpose, the first step is to construct the level scheme of this type of decay. Such a scheme, obtained with the super-asymmetric two-center potential, is plotted for the alpha decay of 223 Ra. It is interesting to note that, diabatically, the level with spin 3/2 emerging from 1i 11/2 (ground state of the parent) reaches an excited state of the daughter in agreement with the experiment. (author)

  19. Alpha particle physics experiments in the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Zweben, S.J.; Budny, R.V.; Darrow, D.S.; Medley, S.S.; Nazikian, R.; Stratton, B.C.; Synakowski, E.J.; Taylor, G.

    2000-01-01

    Alpha particle physics experiments were done on TFTR during its DT run from 1993 to 1997. These experiments utilized several new alpha particle diagnostics and hundreds of DT discharges to characterize the alpha particle confinement and wave-particle interactions. In general, the results from the alpha particle diagnostics agreed with the classical single particle confinement model in MHD quiescent discharges. The alpha loss due to toroidal field ripple was identified in some cases, and the low radial diffusivity inferred for high energy alphas was consistent with orbit averaging over small scale turbulence. Finally, the observed alpha particle interactions with sawteeth, toroidal Alfven eigenmodes and ICRF waves were approximately consistent with theoretical modelling. What was learned is reviewed and what remains to be understood is identified. (author)

  20. Alpha particle collective Thomson scattering in TFTR

    International Nuclear Information System (INIS)

    Machuzak, J.S.; Woskov, P.P.; Rhee, D.Y.; Gilmore, J.; Bindslev, H.

    1993-01-01

    A collective Thomson scattering diagnostic is being implemented on TFTR to measure alpha particle, energetic and thermal ion densities and velocity distributions. A 60 GHz, 0.1-1 kW gyrotron will be used as the transmitter source, and the scattering geometry will be perpendicular to the magnetic field in the extraordinary mode polarization. An enhanced scattered signal is anticipated from fluctuations in the lower hybrid frequency range with this scattering geometry. Millimeter wave collective Thomson scattering diagnostics have the advantage of larger scattering angles to decrease the amount of stray light, and long, high power, modulated pulses to obtain improved signal to noise through synchronous detection techniques

  1. Monitoring of gross alpha in the air and exposure gamma radiation on and around the coal fire power at Paiton

    International Nuclear Information System (INIS)

    Sutarman; Warsono, Asep

    1998-01-01

    Coal is burned in furnace operating at up to 1,700 o C in order to produce electrical energy and ash (bottom ash and fly-ash). The fly-ash is released to the atmosphere or environment around the coal fire power. Therefore, the environmental radioactivity monitoring should be carried out for gross alpha in the air and exposure gamma radiation. The measurement of gross alpha have been carried out using the alpha scintillation counter with the ZnS(Ag) detector, and measurement of gamma radiation using the high pressure ion chamber. The results obtained showed that the gross alpha in the air were the ranging from (7.1 ± 1,2) mBq m -3 to (12.2 ± 1.9) mBq m -3 and the exposure gamma radiation were (3.69 ± 0.11) μR/h to (9.55 ± 0.15) μR/h. The data were still lower than the limit of the maximum permissible concentration and annual intake for breathing but the gross alpha data were higher than in the nuclear installations. (authors)

  2. Ripple enhanced transport of suprathermal alpha particles

    International Nuclear Information System (INIS)

    Tani, K.; Takizuka, T.; Azumi, M.

    1986-01-01

    The ripple enhanced transport of suprathermal alpha particles has been studied by the newly developed Monte-Carlo code in which the motion of banana orbit in a toroidal field ripple is described by a mapping method. The existence of ripple-resonance diffusion has been confirmed numerically. We have developed another new code in which the radial displacement of banana orbit is given by the diffusion coefficients from the mapping code or the orbit following Monte-Carlo code. The ripple loss of α particles during slowing down has been estimated by the mapping model code as well as the diffusion model code. From the comparison of the results with those from the orbit-following Monte-Carlo code, it has been found that all of them agree very well. (author)

  3. Thermonuclear Tokamak plasmas in the presence of fusion alpha particles

    International Nuclear Information System (INIS)

    Anderson, D.; Hamnen, H.; Lisak, M.

    1988-01-01

    In this overview, we have focused on several results of the thermonuclear plasma research pertaining to the alpha particle physics and diagnostics in a fusion tokamak plasma. As regards the discussion of alpha particle effects, two distinct classes of phenomena have been distinguished: the simpler class containing phenomena exhibited by individual alpha particles under the influence of bulk plasma properties and, the more complex class including collective effects which become important for increasing alpha particle density. We have also discussed several possibilities to investigate alpha particle effects by simulation experiments using an equivalent population of highly energetic ions in the plasma. Generally, we find that the present theoretical knowledge on the role of fusion alpha particles in a fusion tokamak plasma is incomplete. There are still uncertainties and partial lack of quantitative results in this area. Consequently, further theoretical work and, as far a possible, simulation experiments are needed to improve the situation. Concerning the alpha particle diagnostics, the various diagnostic techniques and the status of their development have been discussed in two different contexts: the escaping alpha particles and the confined alpha particles in the fusion plasma. A general conclusion is that many of the different diagnostic methods for alpha particle measurements require further major development. (authors)

  4. Alpha particle loss in the TFTR DT experiments

    International Nuclear Information System (INIS)

    Zweben, S.J.; Darrow, D.S.; Herrmann, H.W.

    1995-01-01

    Alpha particle loss was measured during the TFTR DT experiments using a scintillator detector located at the vessel bottom in the ion grad-B drift direction. The DT alpha particle loss to this detector was consistent with the calculated first-orbit loss over the whole range of plasma current I=0.6-2.7 MA. In particular, the alpha particle loss rate per DT neutron did not increase significantly with fusion power up to 10.7 MW, indicating the absence of any new ''collective'' alpha particle loss processes in these experiments

  5. Alpha-Particle Gas-Pressure Sensor

    Science.gov (United States)

    Buehler, M. C.; Bell, L. D.; Hecht, M. H.

    1996-01-01

    An approximate model was developed to establish design curves for the saturation region and a more complete model developed to characterize the current-voltage curves for an alpha-particle pressure sensor. A simple two-parameter current-voltage expression was developed to describe the dependence of the ion current on pressure. The parameters are the saturation-current pressure coefficient and mu/D, the ion mobility/diffusion coefficient. The sensor is useful in the pressure range between 0.1 and 1000 mb using a 1 - mu Ci(241) Am source. Experimental results, taken between 1 and up to 200 mb, show the sensor operates with an anode voltage of 5 V and a sensitivity of 20 fA/mb in nitrogen.

  6. Chromosomal aberrations induced by alpha particles

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M.

    2005-01-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  7. Geometric effects in alpha particle detection from distributed air sources

    International Nuclear Information System (INIS)

    Gil, L.R.; Leitao, R.M.S.; Marques, A.; Rivera, A.

    1994-08-01

    Geometric effects associated to detection of alpha particles from distributed air sources, as it happens in Radon and Thoron measurements, are revisited. The volume outside which no alpha particle may reach the entrance window of the detector is defined and determined analytically for rectangular and cylindrical symmetry geometries. (author). 3 figs

  8. Radionuclide, scintillation cocktail and chemical/color quench influence on discriminator setting in gross alpha/beta measurements by LSC

    International Nuclear Information System (INIS)

    Stojković, Ivana; Tenjović, Branislava; Nikolov, Jovana; Todorović, Nataša

    2015-01-01

    Gross alpha/beta measurements in drinking waters enable radiochemical composition analysis in environmental studies providing efficient screening method that can indicate whether water contains elevated levels of any radionuclide. Routine gross alpha/beta activity monitoring in drinking waters has been carried out for a few years in laboratory for low-level radioactivity measurements in Novi Sad according to ASTM method, performing measurements on liquid scintillation counter Quantulus 1220 which can simultaneously generate alpha/beta spectra of samples by Pulse Shape Analysis (PSA circuit). In this paper, PSA discriminator impact was investigated to ensure obtaining of accurate and reliable alpha/beta activities. One novelty of presented work is PSA parameter setup with two combinations of radionuclides ( 241 Am, 226 Ra and 90 Sr/ 90 Y) with varying activity concentrations. Performed experiments also make contribution to investigations on the manner in which chemical and color quench affect optimal PSA parameter setting and further on, their altogether influence on gross alpha/beta activity measurements. Nitromethane, 15.8 M nitric acid and water, as well as yellow and yellow-orange dye, were used as quenching agents in order to test PSA/interference factor behavior in the presence of quenchers with different quenching strengths. Variation of PSA setting in quenched samples with two different commercially available cocktails (Ultima Gold LLT and OptiPhase HiSafe 3) was also tested. Lastly, application i.e. assessment of obtained PSA-SQP(E) correlation on the obtained results of activity concentrations of few artesian well water samples and colored spiked samples, based on the measured SQP(E) value of samples, has been demonstrated. - Highlights: • Thorough study on influence of relevant factors on optimal PSA level in gross alpha/beta measurements in waters is presented. • Experiments were performed on liquid scintillation counter Quantulus 1220™ according

  9. Rapid determination of gross alpha and beta activity in seafood utilizing microwave digestion and liquid scintillation counting

    International Nuclear Information System (INIS)

    Daniel Sas; Jiri Janda; Alena Tokarova

    2015-01-01

    This paper describes a method for rapid determination of gross alpha and beta activity in seafood using liquid scintillation counting and microwave digestion for fast sample decomposition. The general group of seafood was divided into two groups based on its structure, whether it has shell or not. The selected group of radionuclides was chosen with respect to military significance, radiotoxicity, and possibility of potential misuse. 90 Sr and 239 Pu were selected as model radionuclides. (author)

  10. Plasma flow driven by fusion-generated alpha particles

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1978-05-01

    The confinement of fusion-generated alpha particles will affect the transports of the background plasma particles by the momentum transfer from the energetic alphas. The ions tend to migrate towards the center of plasma (i.e. fuel injection) and electrons towards the plasma periphery. This means the existence of a mechanism which enable to pump out the ashes in the fuel plasma because of the momentum conservation of whole plasma particles. (author)

  11. Effect of alpha particles on Toroidal Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Berk, H.L.

    1992-11-01

    An overview is given of the analytic structure for the linear theory of the Toroidal Alfven Eigenmode (TAE), where multiple gap structures occur. A discussion is given of the alpha particle drive and the various dissipation mechanisms that can stabilize the system. A self-consistent calculation of the TAE mode, for a low-beta high-aspect-ratio plasma, indicates that though the alpha particle drive is comparable to the dissipation mechanisms, overall stability is still achieved for ignited ITER-like plasma. A brief discussion is given of the nonlinear theory for the TAE mode and how nonlinear alpha particle dynamics can be treated by mapping methods

  12. Alpha particle losses during sawtooth activity in Tokamaks

    International Nuclear Information System (INIS)

    Anderson, D.; Lisak, M.

    1988-01-01

    The time evolution of the direct losses of fusion produced alpha particles in Tokamak plasmas characterized by sawtooth activity is investigated. The alpha particle loss rate during a sawtooth period is predicted to change invertedly with the change in bulk plasma parameters but also to contain a characteristic burst at the sawtooth crash. The spectrum of the lost alpha particles is also discussed. The predictions for the time evolution and the spectrum of the losses are in qualitative agreement with recently obtained losses of 15 MeV fusion produced protons in JET. (authors)

  13. Methods and Data Used to Investigate Polonium-210 as a Source of Excess Gross-Alpha Radioactivity in Ground Water, Churchill County, Nevada

    Science.gov (United States)

    Seiler, Ralph L.

    2007-01-01

    Ground water is the major source of drinking water in the Carson River Basin, California and Nevada. Previous studies have shown that uranium and gross-alpha radioactivities in ground water can be greater than U.S. Environmental Protection Agency Maximum Contaminant Levels, particularly in the Carson Desert, Churchill County, Nevada. Studies also have shown that the primary source of the gross-alpha radioactivity and alpha-emitting radionuclides in ground water is the dissolution of uranium-rich granitic rocks and basin-fill sediments that have their origins in the Sierra Nevada. However, ground water sampled from some wells in the Carson Desert had gross-alpha radioactivities greater than could be accounted for by the decay of dissolved uranium. The occurrence of polonium-210 (Po-210) was hypothesized to explain the higher than expected gross-alpha radioactivities. This report documents and describes the study design, field and analytical methods, and data used to determine whether Po-210 is the source of excess gross-alpha radioactivity in ground water underlying the Carson Desert in and around Fallon, Nevada. Specifically, this report presents: 1) gross alpha and uranium radioactivities for 100 wells sampled from June to September 2001; and 2) pH, dissolved oxygen, specific conductance, and Po-210 radioactivity for 25 wells sampled in April and June 2007. Results of quality-control samples for the 2007 dataset are also presented.

  14. Coincidence study of alpha particle fragmentation at E/sub alpha/ = 140 MeV

    International Nuclear Information System (INIS)

    Koontz, R.W.

    1980-01-01

    Results of an experimental study of the interaction of 140 MeV alpha particles with 90 Zr nuclei resulting in fragmentation of the alpha particle are reported. The experimental observations of the study are analyzed and are found to show that alpha particle breakup reactions leading to at least 4-body final states, composed of two charged alpha particle fragments, contribute significantly to the singles yield of charged fragments observed at a fixed forward angle. The conclusions are based on coincidence measurements where one charged fragment is detected at a small forward angle which remains fixed, while the second charged fragment is detected at a series of coplanar secondary angles. The largest coincidence charged particle yield for the multiparticle final state events results from 90 Zr(α,pp)X reactions, where both of the measured protons have energy distributions similar to the proton singles energy distributions. The second largest observed coincidence yield involving two charged fragments arises from 90 Zr(α,pd)X reactions, where the p and d fragments, as in the 90 Zr(α,pp)X reactions also have energy distribution similar to the singles energy distributions. Analysis of additional measurements, where alpha particle fragments at the fixed angle are detected in coincidence with evaporation and nonequilibrium particles at many coplanar angles, show that the alpha particle fragmentation reactions are also generally associated with large energy transfer to the target nucleus. A multiple scattering model of the fragmentation reaction is employed, in conjunction with the experimental observations, to estimate the cross sections for alpha particle fragmentation into multi-particle final states resulting in n, 2n, p, pp, d, dn, dp, t and 3 He fragments. The estimated total cross section for all fragmentation reactions is 755 mb or approximately 38% of the total reaction cross section for 140 MeV alpha particle interactions with 90 Zr

  15. Absorption of lower hybrid waves by alpha particles in ITER

    International Nuclear Information System (INIS)

    Imbeaux, F.; Peysson, Y.; Eriksson, L.G.

    2003-01-01

    Absorption of lower hybrid (LH) waves by alpha particles may reduce significantly the current drive efficiency of the waves in a reactor or burning plasma experiment. This absorption is quantified for ITER using the ray-tracing+2D relativistic Fokker-Planck code Delphine. The absorption is calculated as a function of the superthermal alpha particle density, which is constant in these simulations, for two candidate frequencies for the LH system of ITER. Negligible absorption by alpha particles at 3.7 GHz requires n(alpha,supra) = 7.5 10 16 m -3 , while no significant impact on the driven current is found at 5 GHz, even if n(alpha,supra) = 1.5 10 18 m -3 . (authors)

  16. Gross alpha and beta activity analyses in urine-a routine laboratory method for internal human radioactivity detection.

    Science.gov (United States)

    Chen, Xiaowen; Zhao, Luqian; Qin, Hongran; Zhao, Meijia; Zhou, Yirui; Yang, Shuqiang; Su, Xu; Xu, Xiaohua

    2014-05-01

    The aim of this work was to develop a method to provide rapid results for humans with internal radioactive contamination. The authors hypothesized that valuable information could be obtained from gas proportional counter techniques by screening urine samples from potentially exposed individuals rapidly. Recommended gross alpha and beta activity screening methods generally employ gas proportional counting techniques. Based on International Standards Organization (ISO) methods, improvements were made in the evaporation process to develop a method to provide rapid results, adequate sensitivity, and minimum sample preparation and operator intervention for humans with internal radioactive contamination. The method described by an American National Standards Institute publication was used to calibrate the gas proportional counter, and urine samples from patients with or without radionuclide treatment were measured to validate the method. By improving the evaporation process, the time required to perform the assay was reduced dramatically. Compared with the reference data, the results of the validation samples were very satisfactory with respect to gross-alpha and gross-beta activities. The gas flow proportional counting method described here has the potential for radioactivity monitoring in the body. This method was easy, efficient, and fast, and its application is of great utility in determining whether a sample should be analyzed by a more complicated method, for example radiochemical and/or γ-spectroscopy. In the future, it may be used commonly in medical examination and nuclear emergency treatment.Health Phys. 106(5):000-000; 2014.

  17. Manual for target thickness measurement by alpha particle irradiation

    International Nuclear Information System (INIS)

    Dias, J.F.; Martins, M.N.

    1990-04-01

    A system is described for thin-target thickness measurement through the alpha particle energy loss when them traverse the target. It is also described the program used in the analysis of the target thickness. (L.C.) [pt

  18. Luminescence imaging of water during alpha particle irradiation

    Science.gov (United States)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

    2016-05-01

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  19. Luminescence imaging of water during alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Komori, Masataka; Koyama, Shuji [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

    2016-05-21

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of {sup 241}Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  20. A study on alpha particles range in Cr-39

    International Nuclear Information System (INIS)

    Ibrahim, Z.A.; Talaat, T.M.; Abdel-Aziz, Kh.M.A.; El-Asser, M.R.

    2000-01-01

    Cr-39 plastic nuclear track detector has been used in range determination of alpha particles. A set of experiments was carried out for studying alpha energy and track diameter relationships. This work was done under the optimum conditions of Cr-39 etching in 6.25 N NaOH at 70 degree C for various etching times. Determination of alpha range in Cr-39 recorders was studied at different energy values using the over etched track profile technique. Data are discussed within the framework of track formation theory in plastic foils, comparison between experimental and theoretical values of alpha range is included

  1. A history of nuclear transmutations by natural alpha particles

    International Nuclear Information System (INIS)

    Leone, Matteo

    2005-01-01

    A systematic account of the use of alpha particles up to the 1930s for promoting the disintegration of atoms is here provided. As will be shown, a number of different radium family alpha sources were used in the experiments that led to the discoveries of the proton (Rutherford E 1919 Phil. Mag. 37 581-7) and neutron (Chadwick J 1932 Nature 129 312). The reasons leading to the employment of a particular alpha particle source, as well as the relationship between these sources and the available methods of recording, will be closely addressed

  2. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

    CERN Document Server

    Fujiwara, M.C.; Bertsche, W.; Bowe, P.D.; Bray, C.C.; Butler, E.; Cesar, C.L.; Chapman, S.; Charlton, M.; Fajans, J.; Funakoshi, R.; Gill, D.R.; Hangst, J.S.; Hardy, W.N.; Hayano, R.S.; Hayden, M.E.; Humphries, A.J.; Hydomako, R.; Jenkins, M.J.; Jorgensen, L.V.; Kurchaninov, L.; Lai, W.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seif El Nasr, S.; Silveira, D.M.; Storey, J.W.; Thompson, R.I.; van der Werf, D.P.; Wasilenko, L.; Wurtele, J.S.; Yamazaki, Y.

    2008-01-01

    We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

  3. Alpha-particle emission probabilities of ²³⁶U obtained by alpha spectrometry.

    Science.gov (United States)

    Marouli, M; Pommé, S; Jobbágy, V; Van Ammel, R; Paepen, J; Stroh, H; Benedik, L

    2014-05-01

    High-resolution alpha-particle spectrometry was performed with an ion-implanted silicon detector in vacuum on a homogeneously electrodeposited (236)U source. The source was measured at different solid angles subtended by the detector, varying between 0.8% and 2.4% of 4π sr, to assess the influence of coincidental detection of alpha-particles and conversion electrons on the measured alpha-particle emission probabilities. Additional measurements were performed using a bending magnet to eliminate conversion electrons, the results of which coincide with normal measurements extrapolated to an infinitely small solid angle. The measured alpha emission probabilities for the three main peaks - 74.20 (5)%, 25.68 (5)% and 0.123 (5)%, respectively - are consistent with literature data, but their precision has been improved by at least one order of magnitude in this work. © 2013 Published by Elsevier Ltd.

  4. Alpha particle destabilization of the TAE modes

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    1991-01-01

    The high frequency, low mode number toroidicity-induced Alfven eigenmodes (TAE) are shown to be driven unstable by the circulating and/or trapped α-particles through the wave-particle resonances. For a poloidal harmonic to satisfy the resonance condition it requires that the α-particle birth speed v α ≥ v A /(2|m-nq|), where v A is the Alfven speed, m is the poloidal mode number, and n is the toroidal mode number. To destabilize the TAE modes, the inverse Landau damping associated with the α-particle pressure gradient free energy must overcome the velocity space Landau damping due to both the slowing-down α-particle and the core Maxwellian electron and ion distributions. Stability criteria in terms of the α-particle beta β α , α-particle pressure gradient parameter (ω * /ω A ) (ω * is the α-particle diamagnetic drift frequency), and (v α /v A ) parameters are presented for TFTR, CIT, and ITER tokamaks. The volume averaged α-particle beta threshold for TAE instability also depends sensitively on the core electron and ion temperature. Typically the volume averaged α-particle beta threshold is in the order of 10 -4 if the continuum damping effect is absent. Typical growth rates of the n = 1 TAE mode can be in the order of 10 -2 ω A , where ω A = v A /qR. Stability of higher n TAE modes is also studied. Other types of global Alfven waves are stable due to sideband mode continuum damping resulting from toroidal coupling effects. If the Alfven continuum gap does not exist across the whole minor radius, continuum damping exists for some poloidal harmonics. The continuum damping effect is studied by employing both a resistive MHD stability code (NOVA-R) and an analytical matching method, and the results are presented. 1 ref

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

    International Nuclear Information System (INIS)

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

    2018-01-01

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

  6. The energetic alpha particle transport method EATM

    International Nuclear Information System (INIS)

    Kirkpatrick, R.C.

    1998-02-01

    The EATM method is an evolving attempt to find an efficient method of treating the transport of energetic charged particles in a dynamic magnetized (MHD) plasma for which the mean free path of the particles and the Larmor radius may be long compared to the gradient lengths in the plasma. The intent is to span the range of parameter space with the efficiency and accuracy thought necessary for experimental analysis and design of magnetized fusion targets

  7. Determination of the thoron daughter working level by a one gross alpha-count

    International Nuclear Information System (INIS)

    Bigu, J.; Lau, W.K.

    1983-02-01

    A study has been done on the determination of the thoron daughter Working Level, WL(Tn), by a one gross α-count. The relationship between the gross α-count rate per unit of volume of air sampled and WL(Tn), denoted the F-factor, has been investigated as a function of sampling time, elapsed time from the end of the sampling period, i.e., waiting time, and the thoron daughter disequilibrium ratio [ThC]/[ThB]. It has been found that F depends on both the waiting time and [ThC]/[ThB]. If α-count measurements are made at least 300 min after the end of sampling, F changes by less than 10 percent over the full range of theoretical values of [ThC]/[ThB], i.e., from 0 to 1. The F-factor is independent of [ThC]/[ThB] at approximately 215 min after the end of sampling. This feature can be used to determine WL(Tn) with higher accuracy and at least 1.5 hr earlier than is commonly done using other one gross α-count methods reported in the literature

  8. New technique for alpha particles detection

    International Nuclear Information System (INIS)

    Morsy, A.A.; Khattab, F.M.

    1998-01-01

    Man possesses no biological sensors of ionizing radiation as a consequence he must depend entirely on instrumentation for the detection and measurement of radiation. The recent discovery of the solid state nuclear track detection ( SSNTD ) techniques and its advantages over other dosimeters made them a useful tool for radiation dosimetry. This work is devoted to review and illustrate the application of SSNTD technique in some branches of science and technology specially the newly produced TASTRAK obtained from Track Analysis System Limited, Bristol, UK. The detector is successfully irradiated, chemically etched and calibrated for the aim of the Alpha radiation dosimetry

  9. ITER alpha particle diagnostics using knock-on ion tails

    International Nuclear Information System (INIS)

    Fisher, R.K.; Parks, P.B.; McChesney, J.M.

    1995-09-01

    Alpha particles will play a critical role in the physics and successful operation of ITER. Achieving fusion ignition requires that the α particles created by deuterium-tritium (D-T) reactions deposit a large fraction of their energy in the reacting plasma before they are lost. Toroidal field ripple can localize any alpha particle losses and cause first wall damage. We have proposed a new method of measuring the fast confined α-particle distribution in a reacting plasma. The same elastic collisions that transfer the alpha energy to the D-T plasma ions and allow fusion ignition will also create a high energy tail on the deuterium and tritium ion energy distributions. Some of these energetic tail ions will undergo fusion reactions with the background plasma producing neutrons whose energy is increased significantly above 14 MeV due to the kinetic energy of the reacting ions. Measurement of this high energy tail on the D-T neutron distribution as a function of plasma minor radius would provide information on the alpha density profile with a time response equal to the ion slowing-down time. Although this technique may provide only limited information on the α-particle energy distribution, experimental studies of fast ions on existing tokamaks have shown that the observed slowing-down is essentially classical. Hence the α-energy distribution is expected to be classical except in situations where the α-confinement is poor. The confinement of α's can be affected by ripple losses and a number of instabilities. Toroidal field ripple can cause both prompt orbit losses and stochastic ripple diffusion losses. Magnetohydrodynamic activity, including fishbone instabilities, toroidal Alfven eigenmodes, and sawtooth oscillations, may also affect alpha confinement. The diagnostic proposed here, by monitoring the confined alpha population, can provide valuable information on the confinement of fast alphas in a reacting plasma

  10. Fano factor evaluation of diamond detectors for alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Tsubota, Masakatsu; Shimmyo, Hiroaki [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-8628 (Japan); Sato, Yuki [Naraha Remote Technology Development Center, Japan Atomic Energy Agency, Naraha-machi, Futaba-gun, Fukushima, 979-0513 (Japan); Chayahara, Akiyoshi; Umezawa, Hitoshi; Mokuno, Yoshiaki [Advanced Power Electronics Research Center, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577 (Japan); Watanabe, Hideyuki [Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, 305-8565 (Japan)

    2016-10-15

    This report is the first describing experimental evaluation of Fano factor for diamond detectors. High-quality self-standing chemical vapor deposited diamond samples were produced using lift-off method. Alpha-particle induced charge measurements were taken for three samples. A 13.1 ±0.07 eV of the average electron-hole pair creation energy and excellent energy resolution of approximately 0.3% were found for 5.486 MeV alpha particles from an {sup 241}Am radioactive source. The best Fano factor for 5.486 MeV alpha particles, calculated from experimentally obtained epsilon values and the detector intrinsic energy resolution, was 0.382 ± 0.007. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Advantages of using gyrotron scattering for alpha particle diagnostics

    International Nuclear Information System (INIS)

    Woskoboinikow, P.P.; Cohn, D.R.; Machuzak, J.S.; Myer, R.C.; Rhee, R.Y.

    1987-07-01

    Millimeter-wave gyrotron collective Thomson scattering can be an effective diagnostic technique for the study of alpha particle behavior in ignited plasmas. The measurement of alpha particle density, velocity distribution, and alpha particle induced plasma instabilities can be accomplished with both spatial and temporal resolution. Advantages include long pulse operation which can make possible very high signal to noise ratios and use of millimeter waves which maximizes the Doppler shifted scattered signal in WHz -1 and makes possible scattering angles up to 180 0 . Extraordinary mode scattering at approximately 60 and 200 GHz would be used in TFTR and CIT respectively, and 140 GHz ordinary mode scattering in JET. 8 refs., 1 fig

  12. Applications of alpha particles detectors made of nitrocellulose film

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  13. Alpha-particle radiobiological experiments using thin CR-39 detectors

    International Nuclear Information System (INIS)

    Chan, K. F.; Siu, S. Y. M.; McClella, K. E.; Tse, A. K. W.; Lau, B. M. F.; Nikezic, D.; Richardson, B. J.; Lam, P. K. S.; Fong, W. F.; Yu, K. N.

    2006-01-01

    The present paper studied the feasibility of applying comet assay to evaluate the DNA damage in individual HeLa cervix cancer cells after alpha-particle irradiation. We prepared thin CR-39 detectors (<20 μm) as cell-culture substrates, with UV irradiation to shorten the track formation time. After irradiation of the HeLa cells by alpha particles, the tracks on the underside of the CR-39 detector were developed by chemical etching in (while floating on) a 14 N KOH solution at 37 deg. C. Comet assay was then applied. Diffusion of DNA out of the cells could be generally observed from the images of stained DNA. The alpha-particle tracks corresponding to the comets developed on the underside of the CR-39 detectors could also be observed by just changing the focal plane of the confocal microscope. (authors)

  14. Performance comparison of scintillators for alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-11

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

  15. The interaction of fast alpha particles with pellet ablation clouds

    International Nuclear Information System (INIS)

    McChesney, J.M.; Parks, P.B.; Fisher, R.K.; Olson, R.E.

    1997-01-01

    The energy spectra of energetic confined alpha particles are being measured using the pellet charge exchange method [R. K. Fisher, J. S. Leffler, A. M. Howald, and P. B. Parks, Fusion Technol. 13, 536 (1988)]. The technique uses the dense ablation cloud surrounding an injected impurity pellet to neutralize a fraction of the incident alpha particles, allowing them to escape from the plasma where their energy spectrum can be measured using a neutral particle analyzer. The signal calculations given in the above-mentioned reference disregarded the effects of the alpha particles' helical Larmor orbits, which causes the alphas to make multiple passes through the cloud. Other effects such as electron ionization by plasma and ablation cloud electrons and the effect of the charge state composition of the cloud, were also neglected. This report considers these issues, reformulates the signal level calculation, and uses a Monte-Carlo approach to calculate the neutralization fractions. The possible effects of energy loss and pitch angle scattering of the alphas are also considered. copyright 1997 American Institute of Physics

  16. Self-absorption alpha particle factor in water: interest in the monitoring of specific military sites

    International Nuclear Information System (INIS)

    Cazoulat, A.; Lecompte, Y.; Bohand, S.; Gerasimo, P.

    2007-01-01

    Self-absorption alpha particle factor validation in water: Interest in the monitoring of specific military sites. The population internal intake prevention by radionuclides present in water needs to monitor the radioactive Level of this water. The French public health legislation introduces four radiological parameters for monitoring water, such as the gross alpha radioactivity. Regarding the alpha particle characteristics, a self-absorption factor has to be established beforehand, not to underestimate the real alpha radioactivity in water samples. The aim of this paper is to describe the procedure used by the laboratory of the French army radioprotection service to determine this f factor, which depends on the water residue mass m after evaporation. The relation is f = 0.0253 m + 1.2813. This formula can be employed for such waters used in this experiment and for masses between 0 and 100 mg. The uncertainty associated is about 11% (k = 2). Some water monitoring examples are given. It is specially the case of depleted uranium shells experiment centres, localized in Gramat and Bourges. (authors)

  17. Development of low level alpha particle counting system

    International Nuclear Information System (INIS)

    Minobe, Masao; Kondo, Hiraku; Chinuki, Takashi; Hirano, Hiromichi

    1987-01-01

    Much attention has been paid to the trace analysis of uranium and thorium contained in the base material of LSI or VLSI, since the so-called ''soft-error'' of the memory device was known to be due to alpha particles emitted from these radioactive elements. We have developed an apparatus to meet the needs of estimating such a very small quantity of U and Th of the level of ppb, by directly counting alpha particles using a gas-flow type proportional counter. This method requires no sophisticated analytical skill, and the accuracy of the result is satisfactory. The instrumentation and some application of this apparatus are described. (author)

  18. Continuous air monitor for alpha-emitting aerosol particles

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  19. Theoretical predictions for alpha particle spectroscopic strengths

    International Nuclear Information System (INIS)

    Draayer, J.P.

    1975-01-01

    Multinucleon transfers induced in heavy-ion reactions of the type ( 6 Li,d) furnish a selective probe with which to study the interplay between rotational and clustering phenomena so characteristic of the structure of the light sd-shell nuclei. For these nuclei, theoretical predictions for inter-band as well as intra-band transfer strengths can be made using recently tabulated results for angular momentum dependent SU 3 inclusion R 3 relative spectroscopic strengths and angular momentum independent SU 6 inclusion SU 3 coefficients of fractional parentage. The pure SU 3 (oscillator)-SU 4 (supermultiplet) symmetry limit agrees well with results obtained using available eigenfunctions determined in large shell model calculations. In particular, the scalar nature of a transferred ''alpha''-cluster insures that the effect of spatial symmetry admixtures in the initial and final states of the target and residual nuclei are minimized. Sum rule quantities provide a measure of the probable effects of symmetry breaking. Strength variations within a band are expected; transfers to core excited states are often favored. Results extracted from exact finite range DWBA analyses of ( 6 Li,d) data on 16 , 18 O, 20 , 21 , 22 Ne, 24 , 25 Mg show some anomalies in our understanding of the structure and/or reaction mechanisms. (18 figures) (U.S.)

  20. Absorbed fractions for alpha particles in ellipsoidal volumes

    International Nuclear Information System (INIS)

    Amato, Ernesto; Baldari, Sergio; Italiano, Antonio

    2013-01-01

    Internal dosimetry of alpha particles is gaining attention due to the increasing applications in cancer treatment and also for the assessment of environmental contamination from radionuclides. We developed a Monte Carlo simulation in GEANT4 in order to calculate the absorbed fractions for monoenergetic alpha particles in the energy interval between 0.1 and 10 MeV, uniformly distributed in ellipsoids made of soft tissue. For each volume, we simulated a spherical shape, three oblate and three prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a ‘generalized radius’ was found; and the dependence of the fit parameters on the alpha energy is discussed and fitted by parametric functions. With the proposed formulation, the absorbed fraction for alpha particles in the energy range explored can be calculated for volumes and for ellipsoidal shapes of practical interest. This method can be applied to the evaluation of absorbed fraction from alpha-emitting radionuclides. The contribution to the deposited energy coming from electron and photon emissions can be accounted for exploiting the specific formulations previously introduced. As an example of application, the dosimetry of 213 Bi and its decay chain in ellipsoids is reported. (paper)

  1. Design of a preamplifier for an alpha particles spectrometer

    International Nuclear Information System (INIS)

    Murillo O, R.; Hernandez D, V. M.; Chacon R, A.; Vega C, H. R.

    2010-09-01

    To detect radiation diverse detector types are used, when these are alpha particles proportional type detectors are used, semiconductor, of scintillation or traces. In this work the design results, the construction and the first tests of a spectrometer (preamplifier) are presented for alpha particles that was designed starting from a Pin type photodiode. The system was designed and simulated with a program for electronic circuits. With the results of the simulation phase was constructed the electronics that is coupled to a spectroscopic amplifier and a multichannel analyzer. The total of the system is evaluated analyzing its performance before a triple source of alphas and that they are produced by two smoke detectors of domestic use. Of the tests phase we find that the system allows to obtain in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  2. Experimental determination of alpha particle threshold detection in cellulose nitrate

    International Nuclear Information System (INIS)

    Knoefell, T.M.J.

    1978-01-01

    LR 115, type II, Kodak-Pathe cellulose nitrate pellicles were irradiated perpendicularly with monoenergetic alpha bemas in the energy range 2,5-5,5 Mev. The alpha particle beams were produced by an intense Am 241 source using Argon as energy attenuating. After irradiations, samples were etched with NaOH solutions without agitation at 60 0 C, by different time periods varying from 15 minutes to 3,5 hours. Measurements of density and track diameter were done using optical microscopy. The sample compositions were done by CHN method of combustion gas analysis showing good agreement with the composition of cellulose trinitrate. From detection threshold and from obtained results, the development of latent tracks only occur for alpha particles with stopping power superior to 0,87 +- 0,06 MeV.cm -2 .mg -1 , was verified. (M.C.K.) [pt

  3. 226Ra determination in phosphogypsum by alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Aguado, J.L.; Bolivar, J.P.; Garcia-Tenorio, R.

    1999-01-01

    A radiochemical method for 226 Ra determination by alpha-particle spectrometry in environmental samples has been developed in our laboratory. The method has been validated by measurements in samples with known concentrations of this radionuclide and it has been applied in studies related to 226 Ra behaviour in phosphogypsum (the main by-product of producing phosphoric acid from phosphate rocks). (author)

  4. Preliminary results of the alpha particle registration intercomparison ALRIT

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1976-01-01

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

  5. The role of alpha particles in magnetically confined fusion plasmas

    International Nuclear Information System (INIS)

    Lisak, M.; Wilhelmsson, H.

    1986-01-01

    Recent progress in the confinement of hot plasmas in magnetic fusion experiments throughout the world has intensified interest and research in the physics of D-T burning plasmas especially in the wide range of unresolved theoretical as well as experimental questions associated with the role of alpha particles in such devices. In order to review the state-of-the- art in this field, and to identify new issues and problems for further research, the Symposium on the Role of Alpha Particles in Magnetically Confined Fusion Plasmas was held from 24 to 26 June 1986 at Aspenaesgaarden near Goeteborg, Sweden. About 25 leading experts from nine countries attended the Symposium and gave invited talks. The major part of the programme was devoted to alpha-particle effects in tokamaks but some aspects of open systems were also discussed. The possibilities of obtaining ignition in JET and TFTR as well as physics issues for the compact ignition experiments were considered in particular. A special session was devoted to the diagnostics of alpha particles and other fusion products. In this report are summarised some of the highlights of the symposium. (authors)

  6. Investigation of advanced materials for fusion alpha particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bonheure, G., E-mail: g.bonheure@fz-juelich.de [Laboratory for Plasma Physics, Association “Euratom-Belgian State”, Royal Military Academy, Avenue de la Renaissance, 30 Kunstherlevinglaan, B-1000 Brussels (Belgium); Van Wassenhove, G. [Laboratory for Plasma Physics, Association “Euratom-Belgian State”, Royal Military Academy, Avenue de la Renaissance, 30 Kunstherlevinglaan, B-1000 Brussels (Belgium); Hult, M.; González de Orduña, R. [Institute for Reference Materials and Measurements (IRMM), Retieseweg 111, B-2440 Geel (Belgium); Strivay, D. [Centre Européen d’Archéométrie, Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège (Belgium); Vermaercke, P. [SCK-CEN, Boeretang, B-2400 Mol (Belgium); Delvigne, T. [DSI SPRL, 3 rue Mont d’Orcq, Froyennes B-7503 (Belgium); Chene, G.; Delhalle, R. [Centre Européen d’Archéométrie, Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège (Belgium); Huber, A.; Schweer, B.; Esser, G.; Biel, W.; Neubauer, O. [Forschungszentrum Jülich GmbH, Institut für Plasmaphysik, EURATOM-Assoziation, Trilateral Euregio Cluster, D-52425 Jülich (Germany)

    2013-10-15

    Highlights: ► We examine the feasibility of alpha particle measurements in ITER. ► We test advanced material detectors borrowed from the GERDA neutrino experiment. ► We compare experimental results on TEXTOR tokamak with our detector response model. ► We investigate the detector response in ITER full power D–T plasmas. ► Advanced materials show good signal to noise ratio and alpha particle selectivity. -- Abstract: Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion reactor conditions need further research and development [1,2]. The activation technique is widely used for the characterization of high fluence rates inside neutron reactors. Tokamak applications of the neutron activation technique are already well developed [3] whereas measuring escaping ions using this technique is a novel fusion plasma diagnostic development. Despite low alpha particle fluence levels in present tokamaks, promising results using activation technique combined with ultra-low level gamma-ray spectrometry [4] were achieved before in JET [5,6]. In this research work, we use new advanced detector materials. The material properties beneficial for alpha induced activation are (i) moderate neutron cross-sections (ii) ultra-high purity which reduces neutron-induced background activation and (iii) isotopic tailoring which increases the activation yield of the measured activation product. Two samples were obtained from GERDA[7], an experiment aimed at measuring the neutrinoless double beta decay in {sup 76}Ge. These samples, made of highly pure (9 N) germanium highly enriched to 87% in isotope Ge-76, were irradiated in real D–D fusion plasma conditions inside the TEXTOR tokamak. Comparison of the calculated and the experimentally measured activity shows good agreement. Compared to previously investigated high temperature ceramic material [8

  7. Spot: a new Monte Carlo solver for fast alpha particles

    International Nuclear Information System (INIS)

    Schneider, M.; Eriksson, L.G.; Basiuk, V.; Imbeaux, F.

    2004-01-01

    The predictive transport code CRONOS has been augmented by an orbit following Monte Carlo code, SPOT (Simulation of Particle Orbits in a Tokamak). The SPOT code simulates the dynamics of nonthermal particles, and takes into account effects of finite orbit width and collisional transport of fast ions. Recent developments indicate that it might be difficult to avoid, at least transiently, current holes in a reactor. They occur already on existing tokamaks during advanced tokamak scenarios. The SPOT code has been used to study the alpha particle behaviour in the presence of current holes for both JET and ITER relevant parameters. (authors)

  8. Radon Daughters Background Reduction in Alpha Particles Counting System

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  9. Alpha particle radiography and the track plastic detector CR-39

    International Nuclear Information System (INIS)

    Souza, Bismarck Amilar de.

    1991-05-01

    This work develops the radiographic technique using charged particle beams. This technique complements the X-ray conventional radiography, and presents some advantages in certain cases. The material used as nuclear plastic detector was CR-39, manufactured by Pershre Mould. England, of 250 and 1000 μm nominal thicknesses. The irradiations were made with 7 MeV/Nucleon alpha particles beams, accelerated in the CV-28 Cyclotron of Instituto de Engenharia Nuclear/CNEN - Rio de Janeiro. The etch conditions used were a Na OH 6,25 N solution at 70 0 C, varying the etch time, so that the best etch time was found to be six hours. The calibration curve is presented, which permits images interpretation, showed in terms of light transmittance (obtained using a micro densitometer), and in terms of energy losses suffered by alpha particles in several aluminum degradating thicknesses. This curve was checked by the use of other degradating materials: Mylar, Makrofol, and CR-39 itself. The influence of alpha particle beam FWHM widening on images quality, when it crosses several degradating materials, is also presented. Radiographs of some specimen are presented, including some images obtained varying some irradiation and etch parameters. (author). 62 refs., 22 figs., 19 tabs

  10. On-line gross alpha radiation monitoring of natural waters with extractive scintillating resins

    International Nuclear Information System (INIS)

    Hughes, Lara; De Vol, T.A.

    2003-01-01

    Extractive scintillating resins, which are used to simultaneously separate and quantify radioactivity in aqueous solutions, were developed for low-level alpha radiation monitoring of natural waters. Resins were investigated with bis(2-ethylhexyl)methane-diphosphonic acid (H 2 DEH[MDP], Dipex[reg]) extractant, which has a strong affinity for tri-, tetra- and hexavalent actinides in dilute acids. Extractive scintillating resins were manifested (1) as a mixed bed of scintillating resin and extraction chromatographic resin and (2) by diffusing the organic fluor 2-(1-naphtyl)-5-phenyloxazole into macroporous polystyrene chromatographic resin, then coating with H 2 DEH[MDP], or by coating H 2 DEH[MDP] on scintillating polyvinyltoluene beads. The scintillation light was detected with a modified Hidex Triathler to allow for continuous flow measurements. The average detection efficiencies were 51.7±2.6% and 65.8±10.1% for natural uranium and 241 Am, respectively, for the extractant coated scintillator. The resin was stable for solution flow of up to 1000 ml resulting in rapid real-time quantification of natural uranium in groundwater down to 30 μg/ml

  11. Design of a Quality Control Program for the Measurement of Gross Alpha and Gross Beta Activities (LMPR-CIEMAT); Diseno del Control de Calidad de las Medidas de Actividad Alfa-Beta Total (LMPR-CIEMAT)

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, A.; Yague, L.; Gasco, C.; Navarro, N.; Higueras, E.; Noguerales, C.

    2010-10-21

    In accordance with international standards, general requirements for testing laboratories have to include a quality system for planning, implementing, and assessing the work performed by the organization and for carrying out required quality assurance and quality control. The purpose of internal laboratory quality control is to monitor performance, identify problems, and initiate corrective actions. This report describes the internal quality control to monitor the gross alpha and beta activities determination. Identification of specific performance indicators, the principles that govern their use and statistical means of evaluation are explained. Finally, calculation of alpha and beta specific activities, uncertainties and detection limits are performed. (Author) 10 refs.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  13. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  14. Energy deposition and GDR emission in inelastic alpha particle scattering

    CERN Document Server

    Viesti, G; Fabris, D; Nebbia, G; Cinausero, M; Fioretto, E; Napoli, D R; Prete, G; Hagel, K; Natowitz, J B; Wada, R; Gonthier, P; Majka, Z; Alfarro, R; Zhao, Y; Mdeiwayeh, N; Ho, T

    1999-01-01

    Neutron fold distributions measured for the reaction sup 2 sup 0 sup 9 Bi(alpha,alpha') at 240 MeV have been analyzed with the help of Statistical Model calculations to determine the distribution of excitation energy in the primary target fragments as a function of the projectile energy loss, EL. Results show that the distributions in excitation energy feature a plateau which extends from the kinematical limit E sub x =EL to very small excitations, suggesting a variety of interactions of the beam particles with the target nucleus. Requiring an additional coincidence with a light charged particle leads to selection of a significant higher average excitation energy. This effect is extrapolated to explore results of previous GDR decay measurements in the case of a sup 2 sup 0 sup 8 Pb target. Corrections of derived GDR parameters due to the partial transfer of excitation energy are suggested.

  15. Biological effects of alpha particles in lung tissue

    International Nuclear Information System (INIS)

    Hofmann, W.; Daschil, F.

    1985-01-01

    Allowing for concomitant cellular inactivation, the tumour incidence function can be written as the product of two probabilities, for malignant transformation and for not being killed. Cell survival of mammalian cells in culture after heavy ion irradiation has been described successfully by the formalism of track structure theory for cellular inactivation. Thus a transformation function is derived by extracting cellular radiosensitivity parameters from experimental data on mutation to thioguanine resistance. For defined conditions of radon daughter inhalation, from the fraction of inhaled radionuclides deposited and retained on bronchial airway surfaces are calculated. The LET distribution in sensitive bronchial stem cells hit by alpha particles depends on initial alpha particle energy, airway diameter, and stem cell depth. Applying the methodology of track structure theory and using cellular radiosensitivity parameters for cell killing and mutation, the radiation risk at a given stem cell depth is expressed by the probabilities for cellular survival, for mutation or transformation, and the joint probability for cancer induction. (author)

  16. Alpha-particle simulation using NBI beam and ICRF wave

    International Nuclear Information System (INIS)

    Ogawa, Y.; Hamada, Y.

    1984-07-01

    A new idea to produce the distribution function similar to that of alpha-particles in an ignited plasma has been proposed. This concept is attributed to the acceleration of the injected beam up to about 1 MeV/nucleon by the ICRF wave with cyclotron higher harmonics. This new method makes it possible to perform the simulation experiments for alpha-particles under the condition of moderate plasma parameters (e.g., Tsub(e) = 4 keV, nsub(e) = 3.5x10 19 m -3 and B sub(T) = 3 T). And it is found that 3ωsub(ci) ICRF wave is preferable compared with other cyclotron harmonics, from the viewpoints of the effective tail formation with smaller bulk ion heating and lower amplitude of the applied electric field. The formula for the maximum energy of the extended beam is also derived. (author)

  17. Alpha particle induced soft errors in NMOS RAMs: a review

    International Nuclear Information System (INIS)

    Carter, P.M.; Wilkins, B.R.

    1987-01-01

    The paper aims to explain the alpha particle induced soft error phenomenon using the NMOS dynamic random access memory (RAM) as a model. It discusses some of the many techniques experimented with by manufacturers to overcome the problem, and gives a review of the literature covering most aspects of soft errors in dynamic RAMs. Finally, the soft error performance of current dynamic RAM and static RAM products from several manufacturers are compared. (author)

  18. Alpha-particle diagnostics for the D-T phase

    Energy Technology Data Exchange (ETDEWEB)

    Conroy, S.W.; Bergsaker, H.; Coad, J.P.; Jarvis, O.N.; Marcus, F.B.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking); McCracken, G.M.; Pitts, R.A. (AEA Fusion, Culham (United Kingdom)); Zhu, J. (Sussex Univ., Brighton (United Kingdom))

    1991-01-01

    Diagnostics to examine the lost [alpha] particle flux at JET during the D-T phase are under development. A passive [sup 3]He collector probe has been tested during [sup 3]He NBI and RF heated discharges. [sup 3]He ions with energies of at least 100 keV have been detected; their source is probably due to the metastable component of the [sup 3]He NBI. A code has been developed to model the charged particle fluxes at the wall. (author) 5 refs., 4 figs.

  19. TFTR 60 GHz alpha particle collective Thomson Scattering diagnostic

    International Nuclear Information System (INIS)

    Machuzak, J.S.; Woskov, P.P.; Gilmore, J.; Bretz, N.L.; Park, H.K.; Bindslev, H.

    1995-03-01

    A 60 GHz gyrotron collective Thomson Scattering alpha particle diagnostic has been implemented for the D-T period on TFM. Gyrotron power of 0.1-1 kW in pulses of up to 1 second can be launched in X-mode. Efficient corrugated waveguides are used with antennaes and vacuum windows of the TFTR Microwave Scattering system. A multichannel synchronous detector receiver system and spectrum analyzer acquire the scattered signals. A 200 Megasample/sec digitizer is used to resolve fine structure in the frequency spectrum. By scattering nearly perpendicular to the magnetic field, this experiment will take advantage of an enhancement of the scattered signal which results from the interaction of the alpha particles with plasma resonances in the lower hybrid frequency range. Significant enhancements are expected, which will make these measurements possible with gyrotron power less than 1 kW, while maintaining an acceptable signal to noise ratio. We hope to extract alpha particle density and velocity distribution functions from the data. The D and T fuel densities and temperatures may also be obtainable by measurement of the respective ion cyclotron harmonic frequencies

  20. Alpha-particle and electron capture decay of 209Po

    International Nuclear Information System (INIS)

    Schima, F.J.; Colle, R.

    1996-01-01

    Gamma-ray and Kα X-ray emissions have been measured from a very pure 209 Po source containing less than 0.13% 208 Po activity and no detectable 210 Po (≤2 x 10 -4 %). The alpha-particle emission rate for this source has previously been determined. Data are presented that confirm alpha decay to the 205 Pb excited level at 262.8 keV, with an alpha-particle emission probability (±standard uncertainty) of 0.00559±0.00008. The ratio of K-shell electron capture to total electron capture for the second forbidden unique electron capture decay to the 896.6 keV level in 209 Bi was determined to be 0.594±0.018. The electron capture decay fraction was found to be 0.00454±0.00007, while the probabilities per decay for the 896.6, 262.8, and 260.5 keV gamma rays and the Bi Kα and Pb Kα X-rays were measured as 0.00445±0.00007, 0.00085±0.00002, 0.00254±0.00003, 0.00202±0.00005, and 0.00136±0.00005, respectively. (orig.)

  1. Destabilizing effect of alpha particles in a Maxwellian plasma

    International Nuclear Information System (INIS)

    Wang, M.Y.

    1976-01-01

    Various plasma waves which are possibly excited by MeV alphas have been investigated. For a delta birth distribution it is found that: a) The right-circularly polarized Alfven wave can be excited. Its growth rate is linearly proportional to the α-particle density. b) The drift Alfven wave is stable against α-particles. c) For a uniform temperature, the plasma wave spectrum changes from three branches with n/sub α/ = 0 to four branches for n/sub α/ not equal to 0 case. d) α-particles can destabilize the ion drift acoustic wave even with uniform temperature. However, the ion acoustic wave appears to be stable against fusion products in a fusion grade plasma. e) If their effect on the background plasma spectrum is neglected, α-particles can excite the electromagnetic cyclotron wave in a range of harmonics (band structure). The growth rate is proportional to the square root of α-particle density. f) If the effect of α-particle on the plasma spectrum is included, we find that electromagnetic cyclotron wave is stable

  2. Gas lantern mantle: a low activity alpha particle source

    International Nuclear Information System (INIS)

    Mukherjee, B.; Manzoor, S.

    1991-01-01

    Commercially available gas lantern mantles contain a substantial amount of radioactive ThO 2 . Gas lantern mantles purchased from a Sydney camping shop were incinerated, deposited as a thin layer on a aluminium planchette, and the emitted alpha spectrum was measured with a silicon surfacer barrier detector. The specific activity of the samples was estimated by high resolution gamma spectroscopy using a high purity germanium detector as well as CR-39 solid state nuclear track detectors. The micro-morphology of the incinerated powder was analysed by scanning electron microscopy. The depth dose and LET distribution of alpha particles in soft tissue were calculated from the energy spectrum. 12 refs., 2 tabs., 5 figs

  3. {alpha}-particle induced reactions on yttrium and terbium

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S.; Kumar, B.B. [School of Studies in Physics, Vikram University, Ujjain-456010 (India); Rashid, M.H. [Variable Energy Cyclotron Center, 1/AF, Bidhan Nagar, Calcutta (India); Chintalapudi, S.N. [Inter-University Consortium for DAE Facilities, 3/LB, Bidhan Nagar, Calcutta (India)

    1997-05-01

    The stacked foil activation technique has been employed for the investigation of {alpha}-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the ({alpha},xn) type of reactions were studied using high-resolution HPGe {gamma}-ray spectroscopy. A comparison with Blann{close_quote}s geometric dependent hybrid model has been made using the initial exciton number n{sub 0}=4(4p0h) and n{sub 0}=5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n{sub 0}=4(4p0h). {copyright} {ital 1997} {ital The American Physical Society}

  4. Alpha particle diagnostics using impurity pellet injection (invited)

    International Nuclear Information System (INIS)

    Fisher, R.K.; McChesney, J.M.; Howald, A.W.; Parks, P.B.; Snipes, J.A.; Terry, J.L.; Marmar, E.S.; Zweben, S.J.; Medley, S.S.

    1992-01-01

    We have proposed using impurity pellet injection to measure the energy distribution of the fast confined alpha particles in a reacting plasma [R. K. Fisher et al., Fusion Technol. 13, 536 (1988)]. The ablation cloud surrounding the injected pellet is thick enough that an equilibrium fraction F ∞ 0 (E) of the incident alphas should be neutralized as they pass through the cloud. By observing neutrals created in the large spatial region of the cloud which is expected to be dominated by the heliumlike ionization state, e.g., Li + ions, we can determine the incident alpha distribution dn He 2+ /dE from the measured energy distribution of neutral helium atoms dn He 0 /dE using dn He 0 /dE = dn He 2+ /dE·F ∞ 0 (E,Li + ). Initial experiments were performed on the Texas Experimental Tokamak (TEXT) in which we compared pellet penetration with our impurity pellet ablation model [P. B. Parks et al., Nucl. Fusion 28, 477 (1988)], and measured the spatial distribution of various ionization states in carbon pellet clouds [R. K. Fisher et al., Rev. Sci. Instrum. 61, 3196 (1990)]. Experiments have recently begun on the Tokamak Fusion Test Reactor (TFTR) with the goal of measuring the alpha particle energy distribution during D--T operation in 1993--94. A series of preliminary experiments are planned to test the diagnostic concept. The first experiments will observe neutrals from beam-injected deuterium ions and the high energy 3 He tail produced during ion cyclotron (ICH) minority heating on TFTR interacting with the cloud. We will also monitor by line radiation the charge state distributions in lithium, boron, and carbon clouds

  5. Measurement and analysis of $\\alpha$ particle induced reactions on yttrium

    CERN Document Server

    Singh, N L; Chintalapudi, S N

    2000-01-01

    Excitation functions for /sup 89/Y[( alpha ,3n); ( alpha ,4n); ( alpha , p3n); ( alpha , alpha n); ( alpha , alpha 2n)] reactions were measured up to 50 MeV using stacked foil activation technique and HPGe gamma ray spectroscopy method. The experimental data were compared with calculations considering equilibrium as well as preequilibrium reactions according to the hybrid model of Blann (ALICE/90). For ( alpha , xnyp) type of reactions, the precompound contributions are described by the model. There seems to be indications of direct inelastic scattering effects in ( alpha , alpha xn) type of reactions. To the best of our knowledge, the excitation functions for ( alpha ,4n), ( alpha , p3n), ( alpha , alpha n) and ( alpha , alpha 2n) reactions were measured for the first time. (23 refs).

  6. Measurement and analysis of alpha particle induced reactions on yttrium

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N.L.; Gadkari, M.S. [Baroda Univ. (India). Dept. of Physics; Chintalapudi, S.N. [IUC-DAEF Calcutta Centre, Calcutta (India)

    2000-05-01

    Excitation functions for {sup 89}Y[({alpha},3n);({alpha},4n);({alpha},p3n);({alpha},{alpha}n);({alpha},{alpha}2n)] reactions were measured up to 50 MeV using stacked foil activation technique and HPGe gamma ray spectroscopy method. The experimental data were compared with calculations considering equilibrium as well as preequilibrium reactions according to the hybrid model of Blann (ALICE/90). For ({alpha},xnyp) type of reactions, the precompound contributions are described by the model. There seems to be indications of direct inelastic scattering effects in ({alpha},{alpha}xn) type of reactions. To the best of our knowledge, the excitation functions for ({alpha},4n), ({alpha},p3n), ({alpha},{alpha}n) and ({alpha},{alpha}2n) reactions were measured for the first time. (orig.)

  7. Slowing down of alpha particles in ICF DT plasmas

    Science.gov (United States)

    He, Bin; Wang, Zhi-Gang; Wang, Jian-Guo

    2018-01-01

    With the effects of the projectile recoil and plasma polarization considered, the slowing down of 3.54 MeV alpha particles is studied in inertial confinement fusion DT plasmas within the plasma density range from 1024 to 1026 cm-3 and the temperature range from 100 eV to 200 keV. It includes the rate of the energy change and range of the projectile, and the partition fraction of its energy deposition to the deuteron and triton. The comparison with other models is made and the reason for their difference is explored. It is found that the plasmas will not be heated by the alpha particle in its slowing down the process once the projectile energy becomes close to or less than the temperature of the electron or the deuteron and triton in the plasmas. This leads to less energy deposition to the deuteron and triton than that if the recoil of the projectile is neglected when the temperature is close to or higher than 100 keV. Our model is found to be able to provide relevant, reliable data in the large range of the density and temperature mentioned above, even if the density is around 1026 cm-3 while the deuteron and triton temperature is below 500 eV. Meanwhile, the two important models [Phys. Rev. 126, 1 (1962) and Phys. Rev. E 86, 016406 (2012)] are found not to work in this case. Some unreliable data are found in the last model, which include the range of alpha particles and the electron-ion energy partition fraction when the electron is much hotter than the deuteron and triton in the plasmas.

  8. Measurements of DT alpha particle loss near the outer midplane of TFTR

    International Nuclear Information System (INIS)

    Zweben, S.J.; Darrow, D.S.; Herrmann, H.W.; Redi, M.H.; Schivell, J.; White, R.B.

    1995-07-01

    Measurements of DT alpha particle loss to the outer midplane region of TFTR have been made using a radially movable scintillator detector. The conclusion from this data is that mechanisms determining the DT alpha loss to the outer midplane are not substantially different from those for DD fusion products. Some of these results are compared with a simplified theoretical model for TF ripple-induced alpha loss, which is expected to be the dominant classical alpha loss mechanism near the outer midplane. An example of plasma-driven MHD-induced alpha particle loss is shown, but no signs of any ''collective'' alpha instability-induced alpha loss have yet been observed

  9. Radiolytic gas production in the alpha particle degradation of plastics

    International Nuclear Information System (INIS)

    Reed, D.T.; Hoh, J.; Emery, J.; Hobbs, D.

    1992-01-01

    Net gas generation due to alpha particle irradiation of polyethylene and polyvinyl chloride was investigated. Experiments were performed in an air environment at 30, 60, and 100 degree C. The predominant radiolytic degradation products of polyethylene were hydrogen and carbon dioxide with a wide variety of trace organic species noted. Irradiation of polyvinyl chloride resulted in the formation of HCl in addition to the products observed for polyethylene. For both plastic materials, a strong enhancement of net yields was noted at 100 degree C

  10. Evaluation of charge coupled devices as alpha particle detectors

    International Nuclear Information System (INIS)

    Pace, R.; Haskard, M.; Watts, S.; Holmes-Siedle, A.; Solanky, M.

    1996-01-01

    The ability of the Charge Coupled Device (CCD) to provide spectroscopic and flux information for highly ionising radiation has been investigated. CCDs and related imaging chips are becoming increasingly affordable. In addition advances in technology are producing smaller and better devices. Since imaging chips are based on some variation of the pn-diode structure it is expected and known that they are sensitive to ionising radiation as well as light. Indeed specially designed CCDs are able to be used to image X-rays. This paper reports on the response of CCDs to alpha particles. (author)

  11. Determination of 239Pu/240Pu isotopic ratio by high resolution alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Amoudry, F.; Burger, P.

    1983-05-01

    The development of passivated ion-implanted silicon detectors and of very thin alpha-particle sources improves the resolution of alpha-particle spectra and allows to separate energy pics up to now unseparate. The 239 Pu/ 240 Pu isotopic ratio of a mixture has been measured using the alpha spectrometry deconvolution code DEMO [fr

  12. Innershell ionization by fast protons, alpha particles and carbon ions

    International Nuclear Information System (INIS)

    Dijk, J.H. van.

    1984-01-01

    The subject of this thesis is the study of inner-shell excitations of atoms induced by fast charged particle collisions. A new method is described for measuring the spectrum of delta-electrons emitted by 208 Pb after excitation by 15 MeV protons or 50 MeV alpha particles. Experimental equipment is described. Results of both experiments are presented and compared with PWBA models and with calculations based on a semi-classical approximation. The small-impact-parameter ionization probabilities obtained are then compared with literature. Also small-impact-parameter measurements done with 100 MeV carbon ions are described. Besides K-shell measurements, the author also presents L-subshell ionization probability results for Pb. An appendix is added in which energy straggling problems in solid targets are treated. (Auth./G.J.P.)

  13. Alpha particle cluster states in (fp)-shell nuclei

    International Nuclear Information System (INIS)

    Merchant, A.C.

    1987-07-01

    Alpha particle cluster structure is known experimentally to persist throughout the mass range 16 ≤ A ≤ 20, and has been very successfully described in this region in terms of the Buck-Dover-Vary local potential cluster model. It is argued that an analogous cluster structure should be present in nuclei at the beginning of the (fp) - shell, and the available experimental data are examined to determine likely alpha particle cluster state candidates in the mass range 40 ≤ A ≤ 44. Calculations of the cluster state spectra and mean square cluster-core separation distances (which may be readily used to evaluate E2 electromagnetic transition rates) for sup(40)Ca, sup(42)Ca, sup(42)Sc, sup(43)Sc, sup(43)Ti and sup(44)Ti using the above mentioned model are presented, and compared with experimental measurements where possible. The agreement between theory and experiment is generally good (although inferior to that obtained in the (sd)-shell) and points to the desirability of an extension and improvement of the measurements of the properties of the excited states in these nuclei. (author)

  14. Detection of alpha particles using DNA/Al Schottky junctions

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ta' ii, Hassan Maktuff Jaber, E-mail: hassankirkukly@gmail.com, E-mail: vengadeshp@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), 50603 Kuala Lumpur (Malaysia); Department of Physics, Faculty of Science, University of Al-Muthana, Al-Muthana 66001 (Iraq); Periasamy, Vengadesh, E-mail: hassankirkukly@gmail.com, E-mail: vengadeshp@um.edu.my [Low Dimensional Materials Research Centre (LDMRC), 50603 Kuala Lumpur (Malaysia); Amin, Yusoff Mohd [Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-09-21

    Deoxyribonucleic acid or DNA can be utilized in an organic-metallic rectifying structure to detect radiation, especially alpha particles. This has become much more important in recent years due to crucial environmental detection needs in both peace and war. In this work, we fabricated an aluminum (Al)/DNA/Al structure and generated current–voltage characteristics upon exposure to alpha radiation. Two models were utilized to investigate these current profiles; the standard conventional thermionic emission model and Cheung and Cheung's method. Using these models, the barrier height, Richardson constant, ideality factor and series resistance of the metal-DNA-metal structure were analyzed in real time. The barrier height, Φ value calculated using the conventional method for non-radiated structure was 0.7149 eV, increasing to 0.7367 eV after 4 min of radiation. Barrier height values were observed to increase after 20, 30 and 40 min of radiation, except for 6, 8, and 10 min, which registered a decrease of about 0.67 eV. This was in comparison using Cheung and Cheung's method, which registered 0.6983 eV and 0.7528 eV for the non-radiated and 2 min of radiation, respectively. The barrier height values, meanwhile, were observed to decrease after 4 (0.61 eV) to 40 min (0.6945 eV). The study shows that conventional thermionic emission model could be practically utilized for estimating the diode parameters including the effect of series resistance. These changes in the electronic properties of the Al/DNA/Al junctions could therefore be utilized in the manufacture of sensitive alpha particle sensors.

  15. Cellular dosimetry for radon progeny alpha particles in bronchial tissue

    International Nuclear Information System (INIS)

    Mohamed, A.; Hofmann, W.; Balashazy, I.

    1996-01-01

    Inhaled radon progeny are deposited in different regions of the human bronchial tree as functions of particle size and flow rate. Following deposition and mucociliary clearance, the sensitive bronchial basal and secretory cells are irradiated by two different alpha particle sources: (i) radon progeny in the sol and/or gel phase of the mucous layer, and (ii) radon progeny within the bronchial epithelium. In the case of internally deposited radionuclides, direct measurement of the energy absorbed from the ionizing radiation emitted by the decaying radionuclides is rarely, if ever, possible. Therefore, one must rely on dosimetric models to obtain estimates of the spatial and temporal patterns of energy deposition in tissues and organs of the body. When the radionuclide is uniformly distributed throughout the volume of a tissue of homogeneous composition and when the size of the tissue is large compared to the range of the particulate emissions of the radionuclide, then the dose rate within the tissue is also uniform and the calculation of absorbed dose can proceed without complication. However, if non-uniformities in the spatial and temporal distributions of the radionuclide are coupled with heterogeneous tissue composition, then the calculation of absorbed dose becomes complex and uncertain. Such is the case with the dosimetry of inhaled radon and radon progeny in the respiratory tract. There are increasing demands to obtain a definitive explanation of the role of alpha particles emitted from radon daughters in the induction of lung cancer. Various authors have attempted to evaluate the dose to the bronchial region of the respiratory tract due to the inhalation of radon daughters

  16. Resonant acceleration of alpha particles by ion cyclotron waves in the solar wind

    Science.gov (United States)

    Gomberoff, L.; Elgueta, R.

    1991-06-01

    Preferential acceleration of alpha particles interacting with left-hand polarized ion cyclotron waves is studied. It is shown that a small positive drift velocity between alpha particles and protons can lead to alpha particle velocities well in excess of the proton bulk velocity. During the acceleration process, which is assumed to take place at heliocentric distances less than 0.3 AU, the alpha particle drift velocity should exceed the proton bulk velocity, and then the gap which exists around the alpha particle gyrofrequency should disappear. It is also shown that for proton thermal anisotropies of the order of those observed in fast solar wind, the waves either grow or are not damped excessively, so that the waves can exist and might thus lead to the observed differential speeds. However, the way in which the alpha particles exceed the proton velocity remains unexplained.

  17. Control of alpha-particle transport by ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Chang, C.S.; Imre, K.; Weitzner, H.; Colestock, P.

    1990-01-01

    In this paper control of radial alpha-particle transport by using ion cyclotron range of frequency (ICRF) waves is investigated in a large-aspect-ratio tokamak geometry. Spatially inhomogeneous ICRF wave energy with properly selected frequencies and wave numbers can induce fast convective transports of alpha particles at the speed of order v α ∼ (P RF /n α ε 0 )ρ p , where R RF is the ICRF wave power density, n α is the alpha-particle density, ε 0 is the alpha-particle birth energy, and ρ p is the poloidal gyroradius of alpha particles at the birth energy. Application to International Thermonuclear Experimental Reactor (ITER) plasma is studied and possible antenna designs to control alpha-particle flux are discussed

  18. Alpha particles (citations from the International Aerospace Abstracts data base). Report for 1974-July 1979

    International Nuclear Information System (INIS)

    Mauk, S.C.

    1979-09-01

    This bibliography of citations to the international literature covers various aspects of alpha particles as applied to controlled fusion devices, solar activity, and geomagnetically trapped particles. Included are articles concerning Tokamak devices, plasma heating and control, plasma-particle interactions, solar particles, solar wind, solar flares, energy spectra, and magnetohydrodynamic stability. Articles concerning effects of alpha particles on different kinds of devices are also included

  19. Averaged currents induced by alpha particles in an InSb compound semiconductor detector

    International Nuclear Information System (INIS)

    Kanno, Ikuo; Hishiki, Shigeomi; Kogetsu, Yoshitaka; Nakamura, Tatsuya; Katagiri, Masaki

    2008-01-01

    Very fast pulses due to alpha particle incidence were observed by an undoped-type InSb Schottky detector. This InSb detector was operated without applying bias voltage and its depletion layer thickness was less than the range of alpha particles. The averaged current induced by alpha particles was analyzed as a function of operating temperature and was shown to be proportional to the Hall mobility of InSb. (author)

  20. Study on cytotoxicities induced by alpha particle irradiation combined with NNK treatment

    International Nuclear Information System (INIS)

    Li Ping; Yang Zhihua; Pan Xiujie; Cao Zhenshan; Mi Na; Chen Zhongmin; Liu Gang; Wei Han; Li Huiyin; Zhu Maoxiang

    2006-01-01

    Objective: To investigate cytotoxicities of alpha-particle irradiation combined with NNK treatment. Methods: Exponentially growing immortalized human bronchial epithelial cells were divided into normal control group (NC), alpha particle irradiation group (α), NNK administration group (NNK), NNK administration (100 μg/ml) followed by alpha particle irradiation group (NNK + α), and alphaparticle irradiation followed by NNK administration (100 μg/ml) group (α + NNK). Cell survival fractions were measured by cloning rate of low-density plating cell. Ethidium bromide and 2', 7'-dichlorofluorescein, fluorescent products of the membrane-permeable dyes hydroethine and 2', 7'-dichloroflurescindiacetate were used to monitor the inarticulate reactive oxygen species (ROS) . Damage to membrane permeability was evaluated through testing LDH activity in medium. Results: In the groups exposed to both alpha particles and NNK, the survival rates were significantly lower than that of the groups administrated with the same dose of alpha particles or NNK alone. The levels of intracellular ROS and the activity of LDH in medium were significantly higher than that of the groups administrated with the same dose of alpha particles or NNK alone. Subtracted the NNK effect, the survival rates of the groups received both alpha particle irradiation and NNK treatment were significantly lower than that of alpha particle irradiated only group. However, the intracellular ROS level and the activity of LDH in medium were significantly higher than that of alpha-particle irradiated only group. In addition, the survival rates of the cells in groups exposed to alpha particle irradiation followed by NNK administration were significantly lower than that of cells treated with NNK administration followed by alpha particle irradiation. Conclusions: Alpha particle irradiation and NNK administration had synergisticity in cytotoxicity, and furthermore different schedules of the administration resulted in

  1. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  2. New concept for a wall detector for alpha particles

    International Nuclear Information System (INIS)

    Miley, G.H.; Kislev, H.; Micklich, B.J.

    1985-01-01

    A new concept for a wall-mounted detector is described here that would measure D-T alpha flux and corresponding pitch angle distribution in tokamaks (or related toroidal devices). The sensing element is a conical Micro Channel Ring (MCR) coated with 1 to 2μ of ZnS scintillator (or possibly ZnO). The collimation of the α particles is provided by two circumferential slots at the wall surface. The alpha scintillation events on the MCR are transferred through the ring channels and coupled fiber optics bundle to an external processor. From the magnetic field vector at a given point on the device wall, a certain relation can be set up between the α-induced scintillation position on the MCR and its original pitch angle (i.e., the angle between the α emission from the fusion reaction and the magnetic field vector) which is equal to the local pitch angle since the wall α flux is dominated by prompt losses

  3. Control of alpha particle transport by spatially inhomogeneous ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Chang, C.S.; Imre, K.; Weitzner, H.; Colestock, P.

    1990-02-01

    Control of the radial alpha particle transport by using Ion Cyclotron Range of Frequency waves is investigated in a large-aspect-ratio tokamak geometry. It is shown that spatially inhomogeneous ICRF-wave energy with properly selected frequencies and wave numbers can induce fast convective transport of alpha particles at the speed of order υ alpha ∼ (P RF /n α ε 0 ) ρ p , where P RF is the ICRF-wave power density, n α is the alpha density, ε 0 is the alpha birth energy, and ρ p is the poloidal gyroradius of alpha particles at the birth energy. Application to ITER plasmas is studied and possible antenna designs to control alpha particle flux are discussed. 8 refs., 3 figs

  4. A CMOS integrated pulse mode alpha-particle counter for application in radon monitoring

    International Nuclear Information System (INIS)

    Ahmed, A.; Walkey, D.J.; Tarr, N.G.

    1997-01-01

    A custom integrated circuit for detecting alpha particles for application in the monitoring of radon has been designed and tested. The design uses the reverse-biased well to a substrate capacitance of a p-n junction in a conventional CMOS process as a sense capacitor for incident alpha particles. A simple CMOS inverter is used as an analog amplifier to detect the small potential change induced by an alpha-particle strike on the sense capacitor. The design was implemented in a 1.2-microm conventional CMOS process with a sense capacitor area of 110 microm 2 . Tests carried out under vacuum conditions using a calibrated 241 Am alpha-particle source showed an output voltage swing of ≥2.0 V for an alpha event. The detector is also shown to have good immunity to noise and high-quantum efficiency for alpha particles

  5. Production method of {alpha} particles; Une methode de production des particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Prevot, F [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

    1953-07-01

    It is proposed a method to get an intense beam of {alpha} particles. With a source of ordinary ions, we form a helium beam, once ionized, it is accelerated with an energy of a few hundreds of keV. While crossing a matter any that can be a thin leaf or a gaseous blade, the second electron of helium is pulled with a yield that only depends on the energy of the beam of helium and that is equal to 1/2 for 650 keV. (author) [French] Il est propose une methode pour obtenir un faisceau intense de particules {alpha}. Avec une source d'ions ordinaire, on forme un faisceau d'helium une fois ionise qu'on accelere avec une energie de quelques centaines de keV. En traversant une matiere quelconque qui peut etre sous forme de feuille mince ou de lame gazeuse, le deuxieme electron de l'helium est arrache avec un rendement qui ne depend que de l'energie du faisceau d'helium et qui vaut 1/2 pour 650 keV. (auteur)

  6. Chromosomal aberrations induced by alpha particles; Aberraciones cromosomicas inducidas por particulas {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero C, C.; Brena V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: cgc@nuclear.inin.mx

    2005-07-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  7. Influence of alpha-particles on parameters of plasma confined in open traps

    International Nuclear Information System (INIS)

    Chebotaev, P.Z.

    1987-01-01

    The numerical calculations of the longitudinal motion in multi-mirror reactor have shown that the energy contribution of α-particles has substantial influence on the gain factor (the given off thermonuclear energy/ the initial imparted energy) in the temperature region 5-7 keV. The numerical technique has been developed that takes into account the radial distribution of alpha particles caused by their drag on electrons. This effect is substantial for ρ α /R ≥ 1/2 (where ρ α is alpha particles gyro radius, R is plasma radius), e.g. for Gas-Dinamic trap. In a Tandem-Mirror reactor some part of fusion alpha particles have the probability to slow down to the plasma energy, that can lead to the 'poisoning' of the reactor by the thermonuclear reaction products. The fusion alpha particles can have a strong effect on accumulation of impurities with z ≤ 15 and thermal alpha particles in TMR. (orig.)

  8. Study on cellular genotoxicities induced by alpha particles irradiation in combination with NNK treatment

    International Nuclear Information System (INIS)

    Li Ping; Yang Zhihua; Pan Xiujie; Cao Zhenshan; Mi Na; Chen Zhongmin; Liu Gang; Wei Han; Li Huiying; Zhu Maoxiang

    2006-01-01

    Objective: To investigate cellular genotoxicities of aplha particles irradiation in combination with NNK treatment. Methods: Exponentially growing immortalized human bronchial epithelial cells were divided into the normal control group (NC), alpha particles irradiation (α), NNK administration group (NNK), NNK administration (100 μg/ml) followed by alpha particles irradiation group (NNK + α), and alpha particles irradiation followed by NNK administration (100 μg/ml) group (μ + NNK). DNA damage were detected by single cell gel electrophoresis (SCGE); multinuclear cell assay was used to detect the frequency of the HPRT gene mutation; cell micronucleus frequency were detected by cytogenetic methods. Results: In the group exposed to both alpha particles irradiation and NNK, DNA damage, HPRT gene mutation frequency, and cell micronucleus frequency were significantly higher than those in the same dose groups irradiated with alpha particles or NNK administration alone. Subtracted the NNK effect, DNA damage, HPRT gene mutation frequency and cell micronucleus frequency in the group irradiated by alpha particles in combination with NNK administration were significantly higher than those of alpha particles irradiation alone. Conclusion: The genotoxicity of alpha particles irradiation in combination with NNK administration had synergistic effect. (authors)

  9. Current generation by alpha particles interacting with lower hybrid waves in TOKAMAKS

    International Nuclear Information System (INIS)

    Belikov, V.S.; Kolesnichenko, Ya.I.; Lisak, M.; Anderson, D.

    1990-01-01

    The problem of the influence of fusion generated alpha particles on lower-hybrid-wave current drive is examined. Analysis is based on a new equation for the LH-wave-fast ion interaction which is derived by taking into consideration the non-zero value of the longitudinal wave number. The steady-state velocity distribution function for high energy alpha particles is found. The alpha current driven by LH-waves as well as the RF-power absorbed by alpha particle are calculated. (authors)

  10. Bond scission cross sections for alpha-particles in cellulose nitrate (LR115)

    CERN Document Server

    Barillon, R; Chambaudet, A; Katz, R; Stoquert, J P; Pape, A

    1999-01-01

    Chemical damage created by alpha-particles in cellulose nitrate (LR115) have been studied by infrared spectroscopy. This technique enables identifying the sensitive bonds and giving an order of magnitude of their scission cross sections for given alpha-particle energies. The high cross sections observed suggest a new description of the track etch velocity in this material.

  11. Laser scattering off of alpha particle cyclotron harmonic resonances: Annual performance report

    International Nuclear Information System (INIS)

    Aamodt, R.E.

    1988-01-01

    The active probing of burning plasmas to quantitatively determine high energy alpha particle characteristics is the main purpose of the laser and gyroton scattering program. Progress to date includes a systematic evaluation of homogeneous results, analytical study of alpha particle harmonic resonances, and investigations of finite size detection systems

  12. Simulation of Alpha Particles in Rotating Plasma Interacting with a Stationary Ripple

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Superthermal ExB rotation can provide magnetohydrodynamic (MHD) stability and enhanced confinement to axisymmetric mirrors. However, the rotation speed has been limited by phenomena at end electrodes. A new prediction is that rotation might instead be produced using a magnetic ripple and alpha particle kinetic energy, in an extension of the alpha channeling concept. The interaction of alpha particles with the ripple results in visually interesting and practically useful orbits.

  13. A method to reproduce alpha-particle spectra measured with semiconductor detectors.

    Science.gov (United States)

    Timón, A Fernández; Vargas, M Jurado; Sánchez, A Martín

    2010-01-01

    A method is proposed to reproduce alpha-particle spectra measured with silicon detectors, combining analytical and computer simulation techniques. The procedure includes the use of the Monte Carlo method to simulate the tracks of alpha-particles within the source and in the detector entrance window. The alpha-particle spectrum is finally obtained by the convolution of this simulated distribution and the theoretical distributions representing the contributions of the alpha-particle spectrometer to the spectrum. Experimental spectra from (233)U and (241)Am sources were compared with the predictions given by the proposed procedure, showing good agreement. The proposed method can be an important aid for the analysis and deconvolution of complex alpha-particle spectra. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Determination of {alpha}{sub s} from Gross-Llewellyn Smith sum rule by accounting for infrared renormalon

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, C [Department of Physics, Universidad Tecn. Federico Santa Maria, Valparaiso (Chile); Cvetic, G [Department of Physics, Universidad Tecn. Federico Santa Maria, Valparaiso (Chile); Jeong, K S [Department of Physics, Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of); Lee, Taekoon [Department of Physics, Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of)

    2003-08-01

    We recapitulate the method which resums the truncated perturbation series of a physical observable in a way which takes into account the structure of the leading infrared renormalon. We apply the method to the Gross-Llewellyn Smith (GLS) sum rule. By confronting the obtained result with the experimentally extracted GLS value, we determine the value of the QCD coupling parameter, which turns out to agree with the present world average.

  15. Assessment of radiological risk parameters associated with some selected rivers around oil mineral producing sites in Abia State, Nigeria due to gross alpha and beta radiations

    International Nuclear Information System (INIS)

    Enyinna, Paschal Ikenna; Uzochukwu, Francis C.

    2016-01-01

    The study of gross alpha and beta radiation in environmental components and water bodies in particular is very crucial to the environmental, radiation and medical Physicist as this helps to promote good water quality and environmental hygiene. This research work understudied the radiological risk parameters due to gross alpha and beta radiations associated with three selected rivers around crude oil production sites in Abia State, Nigeria. Gross alpha and beta activities were computed for the three rivers based on analytical measurements carried out using a well-calibrated IN-20 model gas-flow proportional counter. Radiological risk parameters were computed from the activity concentrations which included; annual effective dose equivalent of radiation from ingested water (AEDE), annual gonadal dose equivalent (AGDE), and excess lifetime cancer risk (ELCR). The mean of the total AEDE due to the sum of alpha and beta radiations for the three rivers are 0.868 ± 0.221 mSv/y, 1.008 ± 0.156 mSv/y, and 0.917 ± 0.214 mSv/y; and are above the World Health Organization (WHO) permissible limit of 0.1 mSv/y. The mean of the total AGDE are 4.048 ± 1.063 mSv/y, 4.756 ± 0.739 mSv/y, and 4.295 ± 1.026 mSv/y; and are above the world average limit of 0.3 mSv/y. The mean of the total ELCR are (3.038 ± 0.774) X 10"-"3, (3.529 ± 0.547) X 10"-"3, and (3.210 ± 0.748) X 10"-"3; and are above the world average limit of 0.29 X 10"-"3. Most values of ELCR computed in this work are >6.0 X 10"-"4 estimated to be the risk of fatal and weighted nonfatal health conditions over a lifetime (70 years) derived from the radiation dose of 0.1 mSv/y (WHO permissible limit for drinking water). Drinking water from these surveyed sources could impact negatively on the end users. (author)

  16. Single particle inclusive spectra resulting from the collision of relativistic protons, deuterons, alpha particles, and carbon ions with nuclei

    International Nuclear Information System (INIS)

    Papp, J.

    1975-05-01

    The yields of positive and negative particles resulting from the collision of 1.05 GeV/nucleon and 2.1 GeV/nucleon protons, deuterons, alpha particles, and 1.05 GeV/nucleon carbon nuclei with various targets have been measured. Single particle inclusive cross sections for production of π + , π - , p, d, 3 H, 3 He, and 4 He at 2.5 0 (lab) were obtained. How the results bear on the concepts of limiting fragmentation and scaling, the structure of the alpha particle and deuteron, and the possibility of ''coherent'' production of pions by heavy ions are discussed. (U.S.)

  17. Characterization of Makrofol ® DE 1-1 for alpha particle radiography

    Science.gov (United States)

    El Ghazaly, M.; Aydarous, Abdulkadir; Al-Thomali, Talal A.

    2017-09-01

    Makrofol ® DE 1-1 (bisphenol-A polycarbonate) was investigated for alpha particle radiography. The edge spread function (ESF) was measured by razor-blade's edge. Makrofol ® DE 1-1 detectors were irradiated with perpendicular incident alpha particles of energy 2.5, 4 and 5.4 MeV, thereafter they were etched in 75% 6N KOH+25% C2H5OH at a temperature of 50 °C for different durations. The etched Makrofol®DE 1-1 detectors were imaged with an optical microscope equipped with a CCD camera. The results revealed that the green channel of the original RGB image provides the highest contrast comparing with red and blue channel by a factor of 27.6% of the original RGB image. The image contrast of alpha particle-irradiated Makrofol®DE 1-1 detector was found to be inversely related to the etching time since the alpha particle tracks proceed from a conical phase to spherical phase. The spatial resolution of alpha particle-irradiated Makrofol®DE 1-1 detector, in terms of line spread function, was found to deteriorate as the etching time increases for all examined alpha particle energies. The results revealed the potential capability of Makrofol®DE 1-1 detector as an efficient detector for alpha particle radiography such as autoradiography.

  18. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    Shnishin, K.A.

    2007-01-01

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  19. Lung cancer risk at low doses of alpha particles

    International Nuclear Information System (INIS)

    Hofmann, W.; Katz, R.; Zhang, C.X.

    1986-01-01

    A survey of inhabitant exposures arising from the inhalation of 222 Rn and 220 Rn progeny, and lung cancer mortality has been carried out in two adjacent areas in Guangdong Province, People's Republic of China, designated as the high background and the control area. Annual exposure rates are 0.38 working level months (WLM) per year in the high background, and 0.16 WLM/yr in the control area. In 14 yr of continuous study, from 1970 to 1983, age-adjusted mortality rates were found to be 2.7 per 10(5) living persons of all ages in the high background area, and 2.9 per 10(5) living persons in the control area. From this data, we conclude that we are unable to determine excess lung cancers over the normal fluctuations below a cumulative exposure of 15 WLM. This conclusion is supported by lung cancer mortality data from Austrian and Finnish high-background areas. A theoretical analysis of epidemiological data on human lung cancer incidence from inhaled 2 ]2'' 2 Rn and 220 Rn progeny, which takes into account cell killing as competitive with malignant transformation, leads to the evaluation of a risk factor which is either a linear-exponential or a quadratic-exponential function of the alpha-particle dose. Animal lung cancer data and theoretical considerations can be supplied to support either hypothesis. Thus we conclude that at our current stage of knowledge both the linear-exponential and the quadratic-exponential extrapolation to low doses seem to be equally acceptable for Rn-induced lung cancer risk, possibly suggesting a linear-quadratic transformation function with an exponential cell-killing term, or the influence of risk-modifying factors such as repair or proliferation stimuli

  20. Alpha-emitting 'hot particles' in the vicinity of BNFL Sellafield, Cumbria

    International Nuclear Information System (INIS)

    Whittall, A.J.; Tossell, P.J.

    2000-01-01

    In a survey of environmental samples in the vicinity of BNFL Sellafield, two alpha-emitting radioactive particles were found in samples of grass. One particle appears to be of mineral origin, the other was not definitively identified, but may be a fragment of fuel cladding. Conservative estimates of the activities of these particles are very low. The abundance of radioactive particles in the terrestrial food chain appears to be low, with no evidence for any alpha-emitting hot particles in foodstuffs for consumption by humans. Results suggest that there is no significant dose to man through inhalation or ingestion pathways. (author)

  1. Survival of Acholeplasma laidlawii, strain S2 after irradiation with alpha particles of /sup 241/Americium

    Energy Technology Data Exchange (ETDEWEB)

    Liska, B.; Drasil, V.; Brza, I. (Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav)

    1985-05-23

    A thin layer of dry Acholeplasma laidlawii, strain S2 cells was irradiated with /sup 241/Am alpha particles. D/sub 0/ was 2.54 x 10/sup 7/ - 2.63 x 10/sup 7/ alpha particles/mm/sup 2/ (48 - 50 minutes, 409 - 422 Gy). The extrapolation number was 1.05 - 3.1. The effective cross section at D/sub 0/ was 0.038 - 0.039 ..mu..m/sup 2//alpha particle. A method of preparing thin dry layers of Acholeplasma cells was developed.

  2. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    International Nuclear Information System (INIS)

    1992-01-01

    The objective of our research work is to provide -- with the aid of biophysical models of radiation action -- information on human risks following exposure to radon alpha particles. The approach proposed consists of (1) developing appropriate models (parametric and non-parametric) for alpha radiation induction of relevant end points (survival, cellular transformation), (2) providing an accurate physical characterization of the particle tracks in terms of nanodosimetric distributions, (3) supporting the models by detailed, molecular studies of the direct and indirect effects of alpha particles on DNA. Activities in the second year of this project are described

  3. Quasi-linear absorption of lower hybrid waves by fusion generated alpha particles

    International Nuclear Information System (INIS)

    Barbato, E.; Santini, F.

    1991-01-01

    Lower hybrid waves are expected to be used in a steady state reactor to produce current and to control the current profile and the stability of internal modes. In the ignition phase, however, the presence of energetic alpha particles may prevent wave-electron interaction, thus reducing the current drive efficiency. This is due to the very high birth energy of the alpha particles that may absorb much of the lower hybrid wave power. This unfavourable effect is absent at high frequencies (∼ 8 GHz for typical reactor parameters). Nevertheless, because of the technical difficulties involved in using such high frequencies, it is very important to investigate whether power absorption by alpha particles would be negligible also at relatively low frequencies. Such a study has been carried out on the basis of the quasi-linear theory of wave-alpha particle interaction, since the distortion of the alpha distribution function may enhance the radiofrequency absorption above the linear level. New effects have been found, such as local alpha concentration and acceleration. The model for alpha particles is coupled with a 1-D deposition code for lower hybrid waves to calculate the competition in the power absorption between alphas and electrons as the waves propagate into the plasma core for typical reactor (ITER) parameters. It is shown that at a frequency as low as 5 GHz, power absorption by alpha particles is negligible for conventional plasma conditions and realistic alpha particle concentrations. In more ''pessimistic'' and severe conditions, negligible absorption occurs at 6 GHz. (author). 19 refs, 11 figs, 2 tabs

  4. CIT alpha particle extraction and measurement: Low-Z ablation cloud profile simulation for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    Gerdin, G.; Vahala, L.; El Cashlan, A.G.

    1990-05-01

    In order to determine the expected properties of the ablation cloud of low-Z pellets interacting with a thermonuclear plasma, which in turn is proposed as a charge-neutralization medium for confined alpha particles, a numerical program has been developed. The physical model for this program is based on Park's low-Z pellet-plasma interaction model for the interior of the cloud adjacent to the pellet's surface out to the sonic surface (roughly, a millimeter in separation), and then propagating outward from this region using the conservation laws of enthalpy, momentum, and mass, along with the assumption of charge-state equilibrium. The effects of local heating by the plasma electrons slowing down in the cloud, and ionization of the ablatant material are treated self-consistently in the model. In collaboration with Dr. Paul Parks of General Atomics Corporation, a joint ODU-GAC research plan for modeling low-Z pellet-plasma interactions has been devised, and considerable progress has been made in its implementation. Recently, using a constraint in the ablatant flow, so that it approximates its observed flow along the magnetic field, results from the program were obtained which could be compared with the results from the GAC experiments on TEXT. The predictions of the program are in poor agreement with the TEXT data as to the dimensions of the C +3 region of the cloud along the magnetic field. The failure of the model appears to be the breakdown of the assumption that charge-state equilibrium exists in the cloud. This problem is particularly severe for the TEXT parameters so modifications in the model to include non-equilibrium effects are being implemented

  5. CIT alpha particle extraction and measurement: Low-Z ablation cloud profile simulation for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    Gerdin, G.; Vahala, L.; El Cashlan, A.G.

    1990-01-01

    In order to determine the expected properties of the ablation cloud of low-Z pellets interacting with a thermonuclear plasma, which in turn is proposed as a charge-neutralization medium for confined alpha particles, a numerical program has been developed. The physical model for this program is based on Parks' low-Z pellet-plasma interaction model for the interior of the cloud adjacent to the pellet's surface out to the sonic surface (roughly, a millimeter in separation) and then propagating outward from this region using the conservation laws of enthalpy, momentum, and mass, along with the assumption of charge-state equilibrium. The effects of local heating by the plasma electrons slowing down in the cloud, and ionization of the ablatant material are treated self-consistently in the model. In collaboration with Dr. Paul Parks of General Atomics Corporation, a joint ODU-GAC research plan for modeling low-Z pellet-plasma interactions has been devised, and considerable progress has been made in its implementation. Recently, using a constraint in the ablatant flow, results from the program were obtained which could be compared with the results from the GAC experiments on TEXT. The predictions of the program are in pretty good agreement with the TEXT data as to the dimensions of the C +3 region of the cloud along the magnetic field. Also a small improvement has been made in the low-Z pellet plasma-penetration program, which brings the predictions of the model in closer agreement with the carbon pellet injection experiments on TFTR. 22 refs., 3 figs

  6. Anomalous loss of DT alpha particles in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Hans W. [Princeton Univ., NJ (United States)

    1997-09-01

    An escaping alpha collector probe has been developed for TFTR`s DT phase. Energy distributions of escaping alphas have been determined by measuring the range of α-particles implanted into nickel foils located within the alpha collector. Results at 1.0 MA of plasma current are in good agreement with predictions for first orbit alpha loss. Results at 1.8 MA, however, show a significant anomalous loss of partially thermalized alphas (in addition to the expected first orbit loss), which is not observed with the lost alpha scintillator detectors in DT plasmas, but does resemble the anomalous delayed loss seen in DD plasmas. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations. An experiment designed to study the effect of plasma major radius shifts on α-particle loss has led to a better understanding of α-particle dynamics in tokamaks. Intuitively, one might suppose that confined marginally passing α-particles forced to move toward higher magnetic field during an inward major radius shift (i.e., compression) would mirror and become trapped particles, leading to increased alpha loss. Such an effect was looked for during the shift experiment, however, no significant changes in alpha loss to the 90° lost alpha scintillator detector were observed during the shifts. It is calculated that the energy gained by an α-particle during the inward shift is sufficient to explain this result. However, an unexpected loss of partially thermalized α-particles near the passing/trapped boundary was observed to occur between inward and outward shifts at an intermediate value of plasma current (1.4 MA). This anomalous loss feature is not yet understood.

  7. Cross sections of nuclear reactions induced by protons, deuterons, and alpha particles. Pt.6. Phosphorus

    International Nuclear Information System (INIS)

    Tobailem, Jacques.

    1981-11-01

    Cross sections are reviewed for nuclear reactions induced by protons, deuterons, and alpha particles on phosphorus targets. When necessary, published experimental data are corrected, and, when possible, excitation functions are proposed [fr

  8. Feasibility studies of colorless LR 115 SSNTD for alpha-particle radiobiological experiments

    International Nuclear Information System (INIS)

    Chan, K.F.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2006-01-01

    The feasibility of using the active layer of the colorless LR 115 SSNTD for alpha-particle radiobiological experiments was studied. The track revelation time on the bottom side (the side attached to the polyester base) was much longer than that on the top side (the side not attached to the polyester base) of the active layer so track formation on the top side was more desirable. In relation to this, culture of HeLa cells on the bottom side of the active layer was found feasible although the cultured cell number was relatively smaller. The feasibility of using this SSNTD for alpha-particle radiobiological experiments was demonstrated by culturing cells on the bottom side while performing alpha-particle irradiation and chemical etching on the top side, and by taking photographs of the cells and alpha-particle tracks together under the optical microscope

  9. Proposed neutral-beam diagnostics for fast confined alpha particles in a burning plasma

    International Nuclear Information System (INIS)

    Schlachter, A.S.; Cooper, W.S.

    1986-10-01

    Diagnostic methods for fast confined alpha particles are essential for a burning plasma experiment. Several methods which use energetic neutral beams have been proposed. We review these methods and discuss system considerations for their implementation

  10. Combined effects of alpha particles and depleted uranium on Zebrafish (Danio rerio) embryos

    International Nuclear Information System (INIS)

    Ng, Candy Y.P.; Pereira, Sandrine; Cheng, Shuk Han; Adam-Guillermin, Christelle; Garnier-Laplace, Jacqueline; Yu, Kwan Ngok

    2016-01-01

    The combined effects of low-dose or high-dose alpha particles and depleted uranium (DU) in Zebrafish (Danio rerio) embryos were studied. Three schemes were examined—(i) [I L U L ]: 0.44 mGy alpha-particle dose + 10 µg/l DU exposure, (ii) [I H U H ]: 4.4 mGy alpha-particle dose + 100 µg/l DU exposure and (iii) [I H U L ]: 4.4 mGy alpha-particle dose + 10 µg/l DU exposure—in which Zebrafish embryos were irradiated with alpha particles at 5 h post fertilization (hpf) and/or exposed to uranium at 5–6 hpf. The results were also compared with our previous work, which studied the effects of [I L U H ]: 0.44 mGy alpha-particle dose + 100 µg/l DU exposure. When the Zebrafish embryos developed to 24 hpf, the apoptotic signals in the entire embryos, used as the biological endpoint for this study, were quantified. Our results showed that [I L U L ] and [I H U L ] led to antagonistic effects, whereas [I H U H ] led to an additive effect. The effect found for the previously studied case of [I L U H ] was difficult to define because it was synergistic with reference to the 100 µg/l DU exposure, but it was antagonistic with reference to the 0.44 mGy alpha-particle dose. All the findings regarding the four different schemes showed that the combined effects critically depended on the dose response to each individual stressor. We also qualitatively explained these findings in terms of promotion of early death of cells predisposed to spontaneous transformation by alpha particles, interacting with the delay in cell death resulting from various concentrations of DU exposure

  11. Simple preparation of thin CR-39 detectors for alpha-particle radiobiological experiments

    International Nuclear Information System (INIS)

    Chan, K.F.; Lau, B.M.F.; Nikezic, D.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2007-01-01

    Alpha-particle radiobiological experiments involve irradiating cells with alpha particles and require accurate positions where the alpha particles hit the cells. In the present work, we prepared thin CR-39 detectors from commercially available CR-39 SSNTDs with a thickness of 100 μm by etching them in 1 N NaOH/ethanol at 40 deg. C to below 20 μm. The desired final thickness was achieved within ∼8 h. Such etching conditions can provide relatively small roughness of the detector as revealed by atomic force microscope, and thus provide transparent detectors for radiobiological experiments. UV radiation was employed to shorten track formation time on these thin CR-39 detectors. After exposure to UV light (UVA + B radiation) for 2-3 h with doses from 259 to 389 W/cm 2 , 5 MeV alpha-particle tracks can be seen to develop on these CR-39 detectors clearly under the optical microscope within 2 h in 14 N KOH at 37 deg. C. As an example for practical use, custom-made petri dishes, with a hole drilled at the bottom and covered with a thin CR-39 detector, were used for culturing HeLa cells. The feasibility of using these thin CR-39 detectors is demonstrated by taking photographs of the cells and alpha-particle tracks together under the optical microscope, which can allow the hit positions on the cells by the alpha particles to be determined accurately

  12. Prediction of lung cells oncogenic transformation for induced radon progeny alpha particles using sugarscape cellular automata.

    Science.gov (United States)

    Baradaran, Samaneh; Maleknasr, Niaz; Setayeshi, Saeed; Akbari, Mohammad Esmaeil

    2014-01-01

    Alpha particle irradiation from radon progeny is one of the major natural sources of effective dose in the public population. Oncogenic transformation is a biological effectiveness of radon progeny alpha particle hits. The biological effects which has caused by exposure to radon, were the main result of a complex series of physical, chemical, biological and physiological interactions. The cellular and molecular mechanisms for radon-induced carcinogenesis have not been clear yet. Various biological models, including cultured cells and animals, have been found useful for studying the carcinogenesis effects of radon progeny alpha particles. In this paper, sugars cape cellular automata have been presented for computational study of complex biological effect of radon progeny alpha particles in lung bronchial airways. The model has included mechanism of DNA damage, which has been induced alpha particles hits, and then formation of transformation in the lung cells. Biomarkers were an objective measure or evaluation of normal or abnormal biological processes. In the model, the metabolism rate of infected cell has been induced alpha particles traversals, as a biomarker, has been followed to reach oncogenic transformation. The model results have successfully validated in comparison with "in vitro oncogenic transformation data" for C3H 10T1/2 cells. This model has provided an opportunity to study the cellular and molecular changes, at the various stages in radiation carcinogenesis, involving human cells. It has become well known that simulation could be used to investigate complex biomedical systems, in situations where traditional methodologies were difficult or too costly to employ.

  13. Measurements of geomagnetically trapped alpha particles, 1968-1970. I - Quiet time distributions

    Science.gov (United States)

    Krimigis, S. M.; Verzariu, P.

    1973-01-01

    Results of observations of geomagnetically trapped alpha particles over the energy range from 1.18 to 8 MeV performed with the aid of the Injun 5 polar-orbiting satellite during the period from September 1968 to May 1970. Following a presentation of a time history covering this entire period, a detailed analysis is made of the magnetically quiet period from Feb. 11 to 28, 1970. During this period the alpha particle fluxes and the intensity ratio of alpha particles to protons attained their lowest values in approximately 20 months; the alpha particle intensity versus L profile was most similar to the proton profile at the same energy per nucleon interval; the intensity ratio was nearly constant as a function of L in the same energy per nucleon representation, but rose sharply with L when computed in the same total energy interval; the variation of alpha particle intensity with B suggested a steep angular distribution at small equatorial pitch angles, while the intensity ratio showed little dependence on B; and the alpha particle spectral parameter showed a markedly different dependence on L from the equivalent one for protons.

  14. Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

    CERN Document Server

    Kim, Do Yoon; Shin, Jae Won; Park, Tae-Sun; Hong, Seung-Woo; Andriamonje, Samuel; Kadi, Yacine; Tenreiro, Claudio

    2016-01-01

    We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGA...

  15. Characterization of a alpha particle detector CR-39 exposed to a source of radium

    International Nuclear Information System (INIS)

    Maino, Leandro Marcondes

    2009-01-01

    In this project, the main goal is the characterization of a alpha particle detector CR-39 exposed to a source of radio. Three detectors were exposed to a source of radium and then chemically treated for different periods. This way, we could analyze these samples and collect the information needed to verify that at least one of the chemical attack, there has been a separation of the energies alpha particles incident with distinct peaks, thus characterizing the CR-39 as alpha spectrometer in the range 2.5 to 6.3 MeV . (author)

  16. Techniques for measuring the alpha-particle distribution in magnetically confined plasmas

    International Nuclear Information System (INIS)

    Post, D.E.; Mikkelsen, D.R.; Hulse, R.A.; Stewart, L.D.; Weisheit, J.C.

    1979-10-01

    Methods are proposed for measuring the alpha-particle distribution in magnetically confined fusion plasmas using neutral-atom doping beams, ultraviolet spectroscopy, and neutral particle detectors. In the first method single charge exchange reactions, A 0 + He ++ - > A + (He + )*, are used to populate the n=2 and n=3 levels of He + . The ultraviolet photons from the decaying excited states are Doppler shifted by 5 to 10 Angstroms from those produced by the thermalized alpha-particle ash. In the second method double charge exchange reactions, A 0 + He ++ - > A ++ + He 0 , enable fast neutralized alpha-particles to escape from the plasma and be detected by neutral particle analysers. Detector configurations are analyzed, count rates are estimated and their detectability is discussed. A preliminary analysis of the feasibility of the required neutral beams is presented, and exploratory experiments on existing devices are suggested

  17. Application of CR-39 microfilm for rapid discrimination between alpha-particle sources

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal; Al-karmi, Anan M. [Dept. of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2017-06-15

    This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

  18. Registration of alpha particles in Makrofol-E nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Rammah, Y.S. [Physics Department, Faculty of Science, Menoufia University, Shebin El-Koom (Egypt); Abdalla, Ayman M., E-mail: aymanabdalla62@hotmail.com [Physics Department, Faculty of Sciences and Arts, Najran University, P. O. Box. 11001, Najran (Saudi Arabia); Promising Centre for Sensors and Electronic Devices, Faculty of Arts and Sciences, Najran University (Saudi Arabia); Ashraf, O., E-mail: osama.ashraf@edu.asu.edu.eg [Physics Department, Faculty of Education, Ain Shams University, Cairo 11575 (Egypt); Ashry, A.H. [Physics Department, Faculty of Education, Ain Shams University, Cairo 11575 (Egypt)

    2016-06-15

    Highlights: • Makrofol-E detectors have been irradiated with alpha particles and fission fragments. • Fast detection of alpha particles in Makrofol-E detectors. • Bulk etching rate was calculated from fission track diameters. - Abstract: Fast detection of alpha particles in the range from 1 to 5 MeV in Makrofol-E polycarbonate nuclear track detectors (PCTDs) using a new chemical etchant was investigated. {sup 252}Cf and {sup 241}Am-thin open sources were used for irradiating Makrofol-E detectors with fission fragments and alpha particles in air at normal pressure and temperature (NPT). A chain of experimental work has been carried out using new etchants to register alpha particle in short time in Makrofol-E polycarbonate detectors. The etching efficiency were exhibited a clear dependence on the amount of methanol in the etching solution and etching time. The optimized chemical condition obtained at this stage of development for 200 μm Makrofol-E detectors are (8 ml of 10 N NaOH + 2 ml CH{sub 3}OH) etching solutions at 60 °C for 3 h. In this study; it is possible to observe energy detection windows for Makrofol-E detectors according to applied etching duration. Makrofol-E introduced the characteristic Bragg peak, which indicates the advantages of this detector as alpha spectrometer. Consequently, the suggested new etchant can be developed for heavy ions detection and monitoring radon levels and its daughters.

  19. Analysis of thick source alpha particle spectrum from radium and its daughters in bone

    International Nuclear Information System (INIS)

    Mausner, L.F.; Schlenker, R.A.

    1978-01-01

    The alpha particle energy spectrum of 226 Ra and its four alpha emitting daughters in an ashed, ground bone sample has been resolved into its components using a computerized spectrum stripping algorithm. These calculated results have been compared to direct measurements of the 226 Ra and 214 Po distributions obtained by alpha--gamma coincidence techniques. The ability of the calculation to deconvolute the total spectrum into its five alpha components implies that straightforward alpha counting may be used instead of the very low efficiency 226 Ra alpha--gamma coincidence method. From knowledge of the actual 226 Ra distribution, along with suitable detector energy and efficiency calibrations, one could determine endosteal cell dose rate empirically

  20. Liquid nitrogen enhancement of alpha particle tracks in a polycarbonate detector

    International Nuclear Information System (INIS)

    Pilione, L.J.

    1977-01-01

    Makrofol-E polycarbonate detectors were exposed to 1 to 3 MeV alpha particles and subsequently immersed in liquid nitrogen for various periods of time. The influence of the liquid nitrogen on the track recording properties of the detector has been found by measuring the track densities and diameters. Track densities increase with immersion time with a maximum gain of approximately 9% after 1200 min in liquid nitrogen. Track enhancement decreases with waiting time between the end of alpha particle exposure and the beginning of liquid nitrogen immersion. Track diameters decrease with time after passage of the particles and this process is accelerated by immersion in liquid nitrogen. (author)

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  2. Four-body problem for four bound alpha particles in 16O

    International Nuclear Information System (INIS)

    Osman, A.

    1980-02-01

    The alpha cluster model is used in considering the 16 O nucleus as a bound state of four alpha particles. This problem is represented by integral equations which are exact effective two-particle equations. These equations have the form of two-particle Lippmann-Schwinger equations. The separable expressions are used in approximating the scattering amplitudes in the separable potential model to include also few and small non-separable rest parts of the interactions. The integral equations obtained are manageable and suitable for computations. Numerical calculations are carried out for the 16 O nucleus, with the structure of four bound alpha particles. The obtained binding energy of 16 O with that structure is 16.86 MeV which is in good agreement with the experimental value. (author)

  3. Alpha-particle response characteristics of CR-39

    International Nuclear Information System (INIS)

    Abou El-Khier, A.A.; Gaber, M.; El-Khatib, A.M.; Fawzy, M.A.

    1987-01-01

    The form of the response curve of the polycarbonate CR-39 for α-particles at relatively low energies has been established. The investigation included measurements of both bulk- and track-etch rates. The latter was measured as a function of α-particle energies. (author)

  4. Energy response of detectors to alpha/beta particles and compatibility of the equivalent factors

    International Nuclear Information System (INIS)

    Lin Bingxing; Li Guangxian; Lin Lixiong

    2011-01-01

    By measuring detect efficiency and equivalent factors of alpha/beta radiation with different energies on three types of detectors, this paper compares compatibility of their equivalent factors and discusses applicability of detectors to measuring total alpha/beta radiation. The result shows the relationship between efficiency of alpha/beta radiation and their energies on 3 types of detectors, such as scintillation and proportional and semiconductor counters, are overall identical. Alpha count efficiency display exponential relation with alpha-particle energy. While beta count efficiency display logarithm relation with beta-particle energy, but the curves appears deflection at low energy. Comparison test of energy response also shows that alpha and beta equivalent factors of scintillation and proportional counters have a good compatibility, and alpha equivalent factors of the semiconductor counters are in good agreement with those of the above two types of counters, but beta equivalent factors have obvious difference, or equivalent factors of low energy beta-particle are lower than those of other detectors. So, the semiconductor counter can not be used for measuring total radioactivity or for the measurements for the purpose of food safety. (authors)

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

    International Nuclear Information System (INIS)

    Sgouros, G.

    1996-01-01

    Full text: Once a tumor has metastasized, the possibility of cure is significantly diminished, if not excluded. Since metastatic spread arises due to the release of single tumor cells or tumor cell clusters, treatment regimens following an overt metastasis must include agents that eradicate individual tumor cells and cell clusters or that prevent their dissemination. Alpha particles may be highly effective in eradicating rapidly accessible disease. The effectiveness of alpha particles arises because the amount of energy deposited per unit distance traveled (linear energy transfer or LET) is approximately 400 times greater than that of beta particles (80 keV/μm vs. 0.2 keV/μm). Each traversal of an alpha particle through a cell nucleus results in a very highly ionizing track. Cell survival studies have shown that alpha-particle killing is independent of oxygenation state or cell-cycle during irradiation and that as few as 1 to 6 tracks across the nucleus may result in cell death. Most studies with alpha-particle emitting radionuclides for therapy have examined either bismuth-212 or astatine-211. Both radionuclides are short-lived with 61 minute and 7.2 hour half-lives, respectively, yielding intermediates with 3-minute and 32 year half-lives, respectively. Both emit alpha particles whose range is 40 to 80 μm. Alpha-particle emitting radionuclides have been attached to antibodies against tumor cell associated antigen. Antibodies have been the most widely used vehicle for delivery of alpha particles due to their specificity. Bismuth-212 has demonstrated a significant curative potential with minimal toxicity. In an ascites tumor mouse model, specific targeting and 80% cure following injection of Bi-212-labeled antibody has been observed (Macklis RM et al, Science, 240:1024-1026, 1988). It is important to define the realm of applicability for alpha particle emitting radionuclides. The short half-life of most currently available radionuclides, limits their use to

  6. Characterization of saturation of CR-39 detector at high alpha-particle fluence

    Directory of Open Access Journals (Sweden)

    M. El Ghazaly

    2018-04-01

    Full Text Available The occurrence of saturation in the CR-39 detector reduces and limits its detection dynamic range; nevertheless, this range could be extended using spectroscopic techniques and by measuring the net bulk rate of the saturated CR-39 detector surface. CR-39 detectors were irradiated by 1.5 MeV high alpha-particle fluence varying from 0.06 × 108 to 7.36 × 108 alphas/cm2 from Am-241 source; thereafter, they were etched in a 6.25N NaOH solution at a temperature of 70°C for different durations. Net bulk etch rate measurement of the 1.5 MeV alpha-irradiated CR-39 detector surface revealed that rate increases with increasing etching time and reaches its maximum value at the end of the alpha-particle range. It is also correlated with the alpha-particle fluence. The measurements of UV–Visible (UV–Vis absorbance at 500 and 600 nm reveal that the absorbance is linearly correlated with the fluence of alpha particles at the etching times of 2 and 4 hour. For extended etching times of 6, 10, and 14.5 hour, the absorbance is saturated for fluence values of 4.05 × 108, 5.30 × 108, and 7.36 × 108 alphas/cm2. These new methods pave the way to extend the dynamic range of polymer-based solid state nuclear track detectors (SSNTDs in measurement of high fluence of heavy ions as well as in radiation dosimetry. Keywords: Alpha Particle, Bulk Etch Rate, CR-39 Detector, Saturated Regime, UV–Vis Spectroscopy

  7. Effects of alpha-particles on survival and chromosomal aberrations in human mammary epithelial cells

    Science.gov (United States)

    Durante, M.; Grossi, G. F.; Gialanella, G.; Pugliese, M.; Nappo, M.; Yang, T. C.

    1995-01-01

    We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/microns] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gy; D0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET alpha-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linearquadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges.(ABSTRACT TRUNCATED AT 250 WORDS).

  8. TCAD simulation for alpha-particle spectroscopy using SIC Schottky diode.

    Science.gov (United States)

    Das, Achintya; Duttagupta, Siddhartha P

    2015-12-01

    There is a growing requirement of alpha spectroscopy in the fields context of environmental radioactive contamination, nuclear waste management, site decommissioning and decontamination. Although silicon-based alpha-particle detection technology is mature, high leakage current, low displacement threshold and radiation hardness limits the operation of the detector in harsh environments. Silicon carbide (SiC) is considered to be excellent material for radiation detection application due to its high band gap, high displacement threshold and high thermal conductivity. In this report, an alpha-particle-induced electron-hole pair generation model for a reverse-biased n-type SiC Schottky diode has been proposed and verified using technology computer aided design (TCAD) simulations. First, the forward-biased I-V characteristics were studied to determine the diode ideality factor and compared with published experimental data. The ideality factor was found to be in the range of 1.4-1.7 for a corresponding temperature range of 300-500 K. Next, the energy-dependent, alpha-particle-induced EHP generation model parameters were optimised using transport of ions in matter (TRIM) simulation. Finally, the transient pulses generated due to alpha-particle bombardment were analysed for (1) different diode temperatures (300-500 K), (2) different incident alpha-particle energies (1-5 MeV), (3) different reverse bias voltages of the 4H-SiC-based Schottky diode (-50 to -250 V) and (4) different angles of incidence of the alpha particle (0°-70°).The above model can be extended to other (wide band-gap semiconductor) device technologies useful for radiation-sensing application. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. The inelastic scattering of medium energy {alpha} particles; Sur la diffusion inelastique des particules {alpha} a moyenne energie

    Energy Technology Data Exchange (ETDEWEB)

    Crut, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1960-07-01

    The aim of this work is to find out what are the properties of the so-called 'anomalous states' in medium weight nuclei. These states preferentially excited in the inelastic scattering of medium energy charged particles have an excitation energy at about 4 MeV for nuclei with Z {<=} 29 and in the range 2-3 MeV for high Z nuclei. From a combination of angular distribution data in the elastic and inelastic scattering of 30 MeV {alpha} particles, and correlation data between inelastic {alpha} particles and deexcitation {gamma} rays, we show that for even-even nuclei, we can attribute spin 3 and parity minus to these 'anomalous states'. This is quite in agreement with the interpretation of these levels suggested by Lane as due to collective octupole oscillations. We give a resume of the theories used in the analysis of the data and a description of the experimental set-up. (author) [French] Le but de cette etude est de determiner les proprietes des niveaux dits 'anormalement excites' lors de la diffusion inelastique des particules chargees de moyenne energie sur des noyaux de masse moyenne et lourde. L'energie de ces niveaux est de l'ordre de 4 MeV pour les noyaux avec Z {<=} 29 et de 2 a 3 MeV pour les noyaux de Z plus eleve. De l'examen des courbes de distribution angulaire des particules {alpha} de 30 MeV diffusees elastiquement et inelastiquement, et de la correlation angulaire entre {alpha} excitant ces niveaux 'anormaux' et {gamma} de desexcitation, on deduit que, dans le cas des pair-pair, on peut attribuer a ces niveaux spin 3 et parite moins. Ceci renforce l'hypothese emise par Lane qui attribue ces niveaux a des oscillations octupolaires de la surface du noyau. On donne un apercu des theories utilisees dans l'analyse des resultats et une description des dispositifs experimentaux. (auteur)

  10. Development of detection method for individual environmental particles containing alpha radioactive nuclides

    International Nuclear Information System (INIS)

    Esaka, Konomi; Yasuda, Kenichiro; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu; Nakayama, Shinichi

    2006-01-01

    Artificial radioactive nuclides have been emitted from various sources and have fallen on the surface of the earth as fine particles. Although the characterization of the individual fallout particles is very important, their analysis is difficult. The purpose of this study is to develop a new detection method for individual objective particles containing radioactive nuclides in the environment. The soil or sediment sample was confined in a plastic film and the locations of objective particles were identified with alpha tracks created in a solid-state detectors (BARYOTRAK, Fukuvi Chemical, Ltd) stuck to the both sides of the plastic film. A piece of the film containing the objective particle was cut with a nitrogen laser for following individual particle analysis. This procedure allowed us to detect the objective particle from innumerable number of particles in the environment and characterize the individual particles. (author)

  11. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  12. Efficient alpha particle detection by CR-39 applying 50 Hz-HV electrochemical etching method

    International Nuclear Information System (INIS)

    Sohrabi, M.; Soltani, Z.

    2016-01-01

    Alpha particles can be detected by CR-39 by applying either chemical etching (CE), electrochemical etching (ECE), or combined pre-etching and ECE usually through a multi-step HF-HV ECE process at temperatures much higher than room temperature. By applying pre-etching, characteristics responses of fast-neutron-induced recoil tracks in CR-39 by HF-HV ECE versus KOH normality (N) have shown two high-sensitivity peaks around 5–6 and 15–16 N and a large-diameter peak with a minimum sensitivity around 10–11 N at 25°C. On the other hand, 50 Hz-HV ECE method recently advanced in our laboratory detects alpha particles with high efficiency and broad registration energy range with small ECE tracks in polycarbonate (PC) detectors. By taking advantage of the CR-39 sensitivity to alpha particles, efficacy of 50 Hz-HV ECE method and CR-39 exotic responses under different KOH normalities, detection characteristics of 0.8 MeV alpha particle tracks were studied in 500 μm CR-39 for different fluences, ECE duration and KOH normality. Alpha registration efficiency increased as ECE duration increased to 90 ± 2% after 6–8 h beyond which plateaus are reached. Alpha track density versus fluence is linear up to 10 6  tracks cm −2 . The efficiency and mean track diameter versus alpha fluence up to 10 6  alphas cm −2 decrease as the fluence increases. Background track density and minimum detection limit are linear functions of ECE duration and increase as normality increases. The CR-39 processed for the first time in this study by 50 Hz-HV ECE method proved to provide a simple, efficient and practical alpha detection method at room temperature. - Highlights: • Alpha particles of 0.8 MeV were detected in CR-39 by 50 Hz-HV ECE method. • Efficiency/track diameter was studied vs fluence and time for 3 KOH normality. • Background track density and minimum detection limit vs duration were studied. • A new simple, efficient and low-cost alpha detection method

  13. Modeling of MeV alpha particle energy transfer to lower hybrid waves

    International Nuclear Information System (INIS)

    Schivell, J.; Monticello, D.A.; Fisch, N.; Rax, J.M.

    1993-10-01

    The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large potential benefit

  14. Pre-equilibrium decay process in alpha particle induced reactions on thulium and tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Rao, A.V.; Chintalapudi, S.N. (Inter Univ. Consortium for Dept. of atomic Energy Facilities, Calcutta (India))

    1994-01-01

    Alpha particle induced reactions on the target elements Thulium and Tantalum were investigated upto 60 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for six reactions of [sup 169]Tm([alpha],xn); x=1-4 and [sup 181]Ta([alpha],xn); x=2,4 were studied. The experimental results were compared with the updated version of Hybrid model (ALICE/90) using initial exciton configuration n[sub 0]=4(4pOh). A general agreement was found for all the reactions with this option. (author).

  15. Fluorescent detection of single tracks of alpha particles using lithium fluoride crystals

    International Nuclear Information System (INIS)

    Bilski, P.; Marczewska, B.

    2017-01-01

    Lithium fluoride single crystals were successfully used for fluorescent imaging of single tracks of alpha particles. This was realized with a standard wide-field fluorescent microscope equipped with a 100× objective. Alpha particles create F_2 and F_3"+ color centers in LiF crystals. The subsequent illumination with the blue light (wavelength around 445 nm), excites these centers and produces fluorescence with a broad band peaked at 670 nm. The observed tracks of alpha particles have diameter of about 500 nm. Focusing of the microscope at different depths in a LiF crystal, enables imaging changes of shape and position of tracks, allowing for visualization of their paths. These encouraging results are the first step towards practical application of LiF as fluorescent nuclear track detectors.

  16. Intrinsic efficiency of LR-115 in alpha particles detection: simulations and experiments

    International Nuclear Information System (INIS)

    Aharmim, B.; Sabir, A.; Marah, H.

    2002-01-01

    A numerical simulation is developed to characterize the response of the cellulose nitrate detector ''LR-115 type II'' to alpha particles of different incidence angles and energies. It permits to know whether an alpha particle at a given energy and direction is able to produce a visible etched track or not. For this purpose, a V t -variable track etch rate model is used. We have considered that the track etch rate is a function of the ionization rate and the defect created by delta rays along the alpha particle trajectory. Validation of the model is presented in the form of comparisons between theoretically computed values of the sensitive energy range and the track diameters and experimentally determined ones

  17. An application of 222Rn alpha particle's tracks to uranium exploration

    International Nuclear Information System (INIS)

    Aguilar H, F.

    1981-01-01

    The uranium exploration method is based on the register of 222 Rn alpha particles; 222 Rn gas is generated in the chain 238 U desintegration. The detection of alpha particles was performed with cellulose nitrate films (NTC), located in a grid at the region in study. The alpha particles produce latent tracks in the NTC films; these tracks may be enlarged by chemical etching and are observed with an ordinary optic microscope, ninety seven NTC films were used, these were distributed in an area of approximately seventeen square kilometers, located in the municipalities of Granados and Huasabas in Sonora Mexico, the detectors remain in the ground for a thirty days mean period. The results obtained show an area with high 222 Rn concentration, this can be related with an underground uranium ore deposit. The more important conclusion is that the results obtained in this work can be used as preliminary results for other prospection methods in this particular area. (author)

  18. Silicon surface barrier detector and study of energy spectrum of alpha particles from radioactive source

    International Nuclear Information System (INIS)

    Verma, S.D.; Sinha, Vijaya

    1986-01-01

    The principles of working of three commonly used radiation detectors, namely ionization chambers, scintillation counters with photomultiplier tube (PMT) systems and semiconductor detectors are briefly discussed. Out of the semiconductor detectors, the silicon surface barrier (SSB) detector has distinct advantages for detection of radiations, alpha particles in particular. The experimental setup to obtain the energy spectrum of alpha particles from 241 Am source using SSB fabricated in the Physics Department of Gujarat University, Ahmedabad is described. Its performance is compared with scintillation counter using PMT. SSB detector shows a sharp peak of #approx # 3 per cent energy resolution. The factors affecting the peak, namely, electronic noise, source dependent factors and detector-dependent factors are discussed. A method of calibrating SSB detectors based on energy loss mechanism of alpha particles in thin absorbers is described. Applications of such detectors are indicated. (M.G.B.)

  19. Feasibility of alpha particle measurement in a magnetically confined plasma by CO2 laser Thomson scattering

    International Nuclear Information System (INIS)

    Richards, R.K.; Vander Sluis, K.L.; Hutchinson, D.P.

    1987-08-01

    Fusion-product alpha particles will dominate the behavior of the next generation of ignited D-T fusion reactors. Advanced diagnostics will be required to characterize the energy deposition of these fast alpha particles in the magnetically confined plasma. For small-angle coherent Thomson scattering of a CO 2 laser beam from such a plasma, a resonance in the scattered power occurs near 90 0 with respect to the magnetic field direction. This spatial concentration permits a simplified detection of the scattered laser power from the plasma using a heterodyne system. The signal produced by the presence of fusion-product alpha particles in an ignited plasma is calculated to be well above the noise level, which results from statistical variations of the background signal produced by scattering from free electrons. 7 refs

  20. The alpha-particle and shell models of the nucleus

    International Nuclear Information System (INIS)

    Perring, J.K.; Skyrme, T.H.R.

    1994-01-01

    It is shown that it is possible to write down α-particle wave functions for the ground states of 8 Be, 12 C and 16 O, which become, when antisymmetrized, identical with shell-model wave functions. The α-particle functions are used to obtain potentials which can then be used to derive wave functions and energies of excited states. Most of the low-lying states of 16 O are obtained in this way, qualitative agreement with experiment being found. The shell structure of the 0 + level at 6·06 MeV is analyzed, and is found to consist largely of single-particle excitations. The lifetime for pair-production is calculated, and found to be comparable with the experimental value. The validity of the method is discussed, and comparison made with shell-model calculations. (author). 5 refs, 1 tab

  1. Modifications of the optical properties for DAM-ADC nuclear track detector exposed to alpha particles

    Science.gov (United States)

    Rammah, Y. S.; Awad, E. M.

    2018-05-01

    Modifications of the optical properties of diallyl maleate-allyl diglycol carbonate (DAM-ADC) nuclear detector induced by alpha particles are described. DAM-ADC samples were irradiated perpendicularly by thin 241Am disk source that emits alpha particles with 5.48 MeV. The optical absorption has been measured using the ultraviolet-visible (UV-1100) spectroscopy. It was found that DAM-ADC polymer shows substantial modifications in its optical characteristics upon irradiated with alpha particles with different energies. The optical energy band gap (Egap) for the detector was calculated for the direct and the indirect allowed transitions in K-space using two approaches (Tauc's model and absorption spectrum fitting (ASF) method). Urbach's energy (Ea), number of carbon atoms per conjugated length (N), number of carbon atoms per cluster (M), and refractive index (n) for the present samples were determined. Results reveal that the values of energy gap in direct transition are greater than those of indirect, before and after irradiation. (Egap), (Ea), (N), (M), and (n) of the present samples are changed significantly with irradiation time and value of alpha energy. Results reflect the possibility of using DAM-ADC polymer track detectors to estimate alpha particle energies using the variation of the absorbance.

  2. The semiconductor doping with radiation defects via proton and alpha-particle irradiation. Review

    CERN Document Server

    Kozlov, V A

    2001-01-01

    Paper presents an analytical review devoted to semiconductor doping with radiation defects resulted from irradiation by light ions, in particular, by protons and alpha-particles. One studies formation of radiation defects in silicon, gallium arsenide and indium phosphide under light ion irradiation. One analyzes effect of proton and alpha-particle irradiation on electric conductivity of the above-listed semiconducting materials. Semiconductor doping with radiation defects under light ion irradiation enables to control their electrophysical properties and to design high-speed opto-, micro- and nanoelectronic devices on their basis

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

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, R H

    1994-12-31

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

  4. Plasma features and alpha particle transport in low-aspect ratio tokamak reactor

    International Nuclear Information System (INIS)

    Xu Qiang; Wang Shaojie

    1997-06-01

    The results of the experiment and theory from low-aspect ratio tokamak devices have proved that the MHD stability will be improved. Based on present plasma physics and extrapolation to reduced aspect ratio, the feature of physics of low-aspect ratio tokamak reactor is discussed primarily. Alpha particle confinement and loss in the self-justified low-aspect ratio tokamak reactor parameters and the effect of alpha particle confinement and loss for different aspect ratio are calculated. The results provide a reference for the feasible research of compact tokamak reactor. (9 refs., 2 figs., 3 tabs.)

  5. Ballooning mode instability due to slowed-down ALPHA -particles and associated transport

    International Nuclear Information System (INIS)

    Itoh, Sanae; Itoh, Kimitaka; Tuda, Takashi; Tokuda, Shinji.

    1982-01-01

    The microscopic stability of tokamak plasma, which contains slowed-down alpha-particles and the anomalous fluxes enhanced by the fluctuation, was studied. The local maxwellian distribution with the density inhomogeneity as the equilibrium distribution of electrons, ions and alpha-particles was closen. In the zero-beta limit, two branches of eigenmodes, which are electrostatic, were obtained. The electrostatic ballooning mode became unstable by the grad B drift of particles in the toroidal plasma. It should be noted that there was no critical alpha-particle density and no critical beta-value for the onset of the instability in toroidal plasma even in the presence of the magnetic shear. When the beta-value exceeded the critical beta-value of the MHD ballooning mode, the growth rate approached to that of the MHD mode, and the mode sturcture became very close to that of the MHD mode. The unstable mode in toroidal plasma was the ballooning mode, and was unstable for all plasma parameters. The associated cross-field transport by the ballooning mode is considered. It was found that if the distribution function was assumed to be the birth distribution, the loss rate was very slow and slower than the slowing down time. The effect of alpha-particles on the large scale MHD activity of plasma is discussed. (Kato, T.)

  6. Theory of energetic/alpha particle effects on magnetohydrodynamic modes in tokamaks

    International Nuclear Information System (INIS)

    Chen, L.; White, R.B.; Rewoldt, G.; Colestock, P.; Rutherford, P.H.; Chen, Y.P.; Ke, F.J.; Tsai, S.T.; Bussac, M.N.

    1989-01-01

    The presence of energetic particles is shown to qualitatively modify the stability properties of ideal as well as resistive magnetohydrodynamic (MHD) modes in tokamaks. Specifically, we demonstrate that, consistent with highpower ICRF heating experiments in JET, high energy trapped particles can effectively stabilize the sawtooth mode, providing a possible route to stable high current tokamak operation. An alternative stabilization scheme employing barely circulating energetic particles is also proposed. Finally, we present analytical and numerical studies on the excitations of high-n MHD modes via transit resonances with circulating alpha particles. 14 refs., 3 figs

  7. Nuclear reactions induced by high-energy alpha particles

    Science.gov (United States)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  8. Deep UV emitting scintillators for alpha and beta particle detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y. [Department of Physics and Astronomy, University of Georgia, Athens, GA 30606 (United States); Jia, D.D.; Lewis, L.A. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Feofilov, S.P. [A.F. Ioffe Physical-Technical Institute, St. Petersburg, 194021 (Russian Federation); Meltzer, R.S., E-mail: rmeltzer@physast.uga.ed [Department of Physics and Astronomy, University of Georgia, Athens, GA 30606 (United States)

    2011-03-21

    Several deep UV emitting scintillators, whose emission falls in the solar blind region of the spectrum (200-280 nm), are described and their scintillator properties are characterized. They include LaPO{sub 4}:Pr, YPO{sub 4}:Pr, YAlO{sub 3}:Pr, Pr(PO{sub 3}){sub 3}, YPO{sub 4}:Bi and ScPO{sub 4}. These materials would facilitate the detection of ionizing radiation in open areas, even during the daylight hours, and could be used to support large area surveys that monitor for the presence of ionization radiation due, for example, to system leaks or transfer contamination. These materials can be used in the form of powders, thin films or paints for radiation detection. They are characterized for both beta radiation using electron beams (2-35 keV) and {sup 137}Cs and alpha radiations using {sup 241}Am sources. Their absolute light yields are estimated and are compared to that of Y{sub 2}SiO{sub 5}:Ce. Their light yields decrease as a function of electron energy but at 10 keV they approach 8000 ph/MeV.

  9. Actinium-225 and Bismuth-213 Alpha Particle Immunotherapy of Cancer

    International Nuclear Information System (INIS)

    Scheinberg, D.

    2013-01-01

    Nuclides with appropriate half-lives and emission characteristics that would be potent enough to kill neoplastic cells in the small quantities that reach targets in vivo, include the high linear energy transfer (LET) alpha emitters such as Actinium-225 and Bi-213. We developed methods for the attachment of radiometals via bifunctional chelates to monoclonal antibodies (mAb) without loss of immunoreactivity. We developed alphaemitting Bi-213 lintuzumab constructs, characterized and qualified them in preclinical models, and took them into human clinical trials in patients with AML. Safety, anti-leukemic activity, and complete responses (CR’s) have been demonstrated through phase 2 trilas. Bi-213 is produced in a portable small generator device based on Ac- 225 in the hospital nuclear medicine lab. The isotope is then purified, attached to the antibody, and the product is qualified and processed. Despite this success, the major obstacle to the widespread use of these drugs remains the short 213 Bi half-life (46 minutes), which poses a large logistical hurdle before injection and limits its delivery to only the most accessible cancer cells after injection

  10. Transformation of mouse embryo (C3H 10T1/2) cells by alpha particles

    International Nuclear Information System (INIS)

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

    1977-01-01

    Mammalian cells in culture (C3H mouse 10T1/2 cells) have been shown here for the first time to be transformed by alpha irradiation when cells were irradiated with 5.6 MeV alpha particles from a Tandem Van de Graaff machine. Malignant tumors were induced following inoculation of the transformed cells into syngeneic hosts. Unirradiated control cells injected at the same concentration have, so far, failed to produce tumors. The morphology of the transformed foci was remarkably similar to that obtained by x rays and chemicals but different from virally transformed cells. When the cells were seeded at low density in the exponential growth phase, the transformation frequency per surviving cell increased approximately as the cube of the dose and peaked at an alpha particle fluence between 1.5 and 2.5 x 10 7 alpha particles per cm 2 (205 to 342 rads). The frequency of the transformation was found to be greatly dependent on the number of cells per dish irradiated. Irradiation of larger numbers resulted in much lower frequencies of transformation. The maximum transformation frequency observed in nine separate experiments was 4 percent of the surviving cells. At doses greater than 200 rads the transformation frequency per surviving cell remained constant. The present results permit us to conclude that alpha irradiation may, indeed, be able to exert a direct effect on the genome of the cell to produce malignancy without any external immunological or hormonal influences

  11. Scanning of irradiated silicon detectors using $\\alpha$ particles and low energy protons

    CERN Document Server

    Casse, G L; Glaser, M; Kohout, Z; Konícek, J; Lemeilleur, F; Leroy, C; Linhart, V; Mares, J J; Pospísil, S; Roy, P; Sopko, B; Sinor, M; Svejda, J; Vorobel, V; Wilhelm, I

    1999-01-01

    In a spectroscopic study of non-irradiated and proton-irradiated silicon diodes, the detectors were illuminated from the front side and from the rear side by various alpha particle sources (mainly ThC') and by monoenergetic protons with energies from 1.0 to 2.5~MeV. Their response characteristics have been studied as a function of the incoming particle energy and the applied bias voltage. The charge collection efficiency was determined as a function of fluence

  12. Bulk GaN alpha-particle detector with large depletion region and improved energy resolution

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qiang; Mulligan, Padhraic [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Wang, Jinghui [Department of Radiology, Stanford University, 1201 Welch Rd, Stanford, CA 94305 (United States); Chuirazzi, William [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Cao, Lei, E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States)

    2017-03-21

    An alpha-particle detector was fabricated using a freestanding n-type bulk GaN wafer with a Au/Ni/GaN sandwich Schottky structure. Current–voltage measurements at room temperature revealed a Schottky contact with a leakage current of 7.53±0.3 nA at a reverse bias of 200 V. The detector had a large depletion depth that can capture much of the energy from 5.486 MeV alpha particles emitted from a {sup 241}Am source. The resolution of its alpha-particle energy spectrum was improved to 2.2±0.2% at 5.486 MeV under a bias of 550 V. This superior resolution was attributed to the shortening of the carrier transit time and the large energy deposition within the large depletion depth, i.e., 27 µm at −550 V, which all resulted in a more complete charge collection. A model developed using the ATLAS simulation framework from Silvaco Inc. was employed to study the charge collection process. The simulation results were found to agree closely with the experimental results. This detector will be beneficial for research at neutron scattering facilities, the International Thermonuclear Experimental Reactor, and the Large Hadron Collider, among other institutions, where the Si-based charged particle detectors could be quickly degraded in an intense radiation field. - Highlights: • An alpha-particle detector based on a Schottky-structured GaN wafer was tested. • The detector's large depletion depth enables fuller energy spectra to be obtained. • The best resolution yet attained in GaN alpha-particle spectrometry was achieved. • The detector's short carrier transit time resulted in improved charge collection. • This detector is usable in extreme conditions, including intense radiation fields.

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

    International Nuclear Information System (INIS)

    Terini, R.A.

    1990-01-01

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

  14. On the acceleration of alpha particles in the fast solar wind

    International Nuclear Information System (INIS)

    Gomberoff, L.; Hernandez, R.

    1992-01-01

    Recently, Gomberoff and Elgueta (1991) showed that in a plasma composed of anisotropic protons and alpha particles drifting along an external magnetic field with a small velocity relative to the protons, strong left-hand polarized electromagnetic ion cyclotron waves can be generated. These waves can accelerate the alpha particles to velocities well in excess of the proton bulk velocity. Here the authors assume a more realistic model of the solar wind by considering a double-humped proton distribution. It is shown that the secondary proton beam has no important effects on the ion cyclotron waves for beam densities of the order of those observed in fast solar wind conditions. The fact that the alpha proton drift velocity is modulated by the Alfven velocity remains unexplained

  15. Cryogenic Microcalorimeter System for Ultra-High Resolution Alpha-Particle Spectrometry

    Science.gov (United States)

    Croce, M. P.; Bacrania, M. K.; Hoover, A. S.; Rabin, M. W.; Hoteling, N. J.; LaMont, S. P.; Plionis, A. A.; Dry, D. E.; Ullom, J. N.; Bennett, D. A.; Horansky, R. D.; Kotsubo, V.; Cantor, R.

    2009-12-01

    Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ˜15-μK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis. This paper will discuss design and operation of our microcalorimeter alpha-particle spectrometer, and will show recent results.

  16. Determination of alpha particle detection efficiency of an imaging plate (IP) detector

    International Nuclear Information System (INIS)

    Rahman, N.M; Iida, Takao; Yamazawa, Hiromi; Moriizumi, Jun

    2006-01-01

    In order to determine the detection efficiency of the imaging plate (IP) detector, the true radioactivity of the alpha particles, which sampled in the collection media, should be known. The true radioactivity could be accurately predicted with the help of the reference alpha spectrometer measurement. The detection efficiency calculated for the IP was estimated with the theoretical curve and the experimental data. It is assumed that the air sample contained the decay products of both 222 Rn and 220 Rn series, the most significant sources of alpha particles. The present study estimated the detection efficiency of the IP as 39.3% with an uncertainty of 2.9 that is well enough to confirm the future use of the IP as a radiation detector. Experimental materials and methods are described. (S.Y.)

  17. Alpha particle density and energy distributions in tandem mirrors using Monte-Carlo techniques

    International Nuclear Information System (INIS)

    Kerns, J.A.

    1986-05-01

    We have simulated the alpha thermalization process using a Monte-Carlo technique, in which the alpha guiding center is followed between simulated collisions and Spitzer's collision model is used for the alpha-plasma interaction. Monte-Carlo techniques are used to determine the alpha radial birth position, the alpha particle position at a collision, and the angle scatter and dispersion at a collision. The plasma is modeled as a hot reacting core, surrounded by a cold halo plasma (T approx.50 eV). Alpha orbits that intersect the halo lose 90% of their energy to the halo electrons because of the halo drag, which is ten times greater than the drag in the core. The uneven drag across the alpha orbit also produces an outward, radial, guiding center drift. This drag drift is dependent on the plasma density and temperature radial profiles. We have modeled these profiles and have specifically studied a single-scale-length model, in which the density scale length (r/sub pD/) equals the temperature scale length (r/sub pT/), and a two-scale-length model, in which r/sub pD//r/sub pT/ = 1.1

  18. alpha-particle radioactivity from LR 115 by two methods of analysis

    CERN Document Server

    Azkour, K; Adloff, J C; Pape, A

    1999-01-01

    LR115 track detectors were exposed to samples of Moroccan phosphate and phosphogypsum to measure their alpha-particle radioactivity. Then two formalisms were used for the dosimetry: simulation by a Monte Carlo method and determination of concentrations from a numerically integrated track registration equation. The results were compared with those deduced gamma-ray spectrometry.

  19. Iota-dependent resonance absorption in the optical model description of alpha particle elastic scattering

    International Nuclear Information System (INIS)

    Chyla, K.; Jarczyk, L.; Maciuk, B.; Zipper, W.

    1976-01-01

    Alpha particle scattering from 28 Si has been studied at five bombarding energies from 23.5 to 28.5 MeV. iota-dependent resonance absorption has been introduced to the optical model analysis of 28 Si (α,β) 28 Si reaction. (author)

  20. Alpha-particle breakup at incident energies of 20 and 40 MeV/nucleon

    International Nuclear Information System (INIS)

    Wu, J.R.; Chang, C.C.; Holmgren, H.D.; Koontz, R.W.

    1979-01-01

    The breakup of alpha particles at incident energies of 20 and 40 MeV/nucleon on 27 Al, 58 Ni, 90 Zr, and 209 Bi has been studied. It was found that the breakup cross section decreases rapidly with increasing angles and increases with increasing target mass and incident energy. The total breakup yield, summed over all charged fragments, is approx.15--35% of the alpha-particle total reaction cross section, and has an approximate A/sup 1/3/ dependence. The ratios of breakup yields among different fragments are approximately p:d:t: 3 He approx. = 13:3:1:2, and are roughly independent of the incident energy and the target nucleus. These features suggest that the alpha-particle fragmentation is a peripheral process and is dominated by the properties of the incident projectile. A simple plane-wave alpha-particle breakup model gives a rather good description to the experimental data. In addition to the breakup deuteron peak at half of the beam energy, a second peak at quarter of the beam energy (or the same energy as the breakup proton peak) is observed. This peak might be due to a two-step breakup-pickup process

  1. A variational calculation of 12C in the alpha-particle model

    International Nuclear Information System (INIS)

    Portilho, O.

    1973-01-01

    Some physical properties of three structureless alpha particles interacting through two-body potentials were discussed. Comparison between them and the corresponding experimental observations for the 12 C nucleus is done. The wave function is expanded in terms of translationally invariant harmonic-oscillator states, the coefficients being variational parameters

  2. Experimental setup for studying the effects of alpha particles on zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Yum, E.H.W.; Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Lin, A.C.C.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China)], E-mail: peter.yu@cityu.edu.hk

    2007-11-15

    In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 {mu}m were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human.

  3. Study on 16O in the alpha particle model using three-body forces

    International Nuclear Information System (INIS)

    Agrello, D.A.

    1979-01-01

    A study of the ground state of 16 O is made using an alpha particle model, all without internal structure, interacting through two-and three-body forces. Some nuclear properties of 16 O, such as binding energy and gaps, are also studied. (L.C.) [pt

  4. Cr/alpha-Cr2O3 monodispersed spherical core-shell particles based solar absorbers

    CSIR Research Space (South Africa)

    Khamlich, S

    2011-07-01

    Full Text Available as reported. The coated Cr/alpha-Cr2O3 spherical particles on rough copper substrates by a simple self-assembly-like method were characterized by scanning electron microscopy, energy dispersive spectrometry, Raman spectroscopy, and diffuse reflectance UV...

  5. Experimental setup for studying the effects of alpha particles on zebrafish embryos

    International Nuclear Information System (INIS)

    Yum, E.H.W.; Ng, C.K.M.; Lin, A.C.C.; Cheng, S.H.; Yu, K.N.

    2007-01-01

    In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 μm were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human

  6. Operation of a high-purity silicon diode alpha particle detector at 1.4 K

    International Nuclear Information System (INIS)

    Martoff, C.J.; Kaczanowicz, E.; Neuhauser, B.J.; Lopez, E.; Zhang, Y.; Ziemba, F.P.

    1991-01-01

    Detection of alpha particles at temperatures as low as 1.4 K was demonstrated using a specially fabricated Si diode. The diode was 475 mm 2 by 0.280 mm thick, fabricated from high-purity silicon with degenerately doped contacts. This is an important step toward development of dual-mode (ionization plus phonon) silicon detectors for low energy radiation. (orig.)

  7. Alpha-particle detection based on the BJT detector and simple, IC-based readout electronics

    Energy Technology Data Exchange (ETDEWEB)

    Rovati, L; Bonaiuti, M [Dipartimento di Ingegneria dell' Informazione, Universita di Modena e Reggio Emilia, Modena (Italy); Bettarini, S [Dipartimento di Fisica, Universita di Pisa and INFN Pisa, Pisa (Italy); Bosisio, L [Dipartimento di Fisica, Universita di Trieste and INFN Trieste, Trieste (Italy); Dalla Betta, G-F; Tyzhnevyi, V [Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento e INFN Trento, Trento (Italy); Verzellesi, G [Dipartimento di Scienze e Metodi dell' Ingegneria, Universita di Modena e Reggio Emilia and INFN Trento, Reggio Emilia (Italy); Zorzi, N, E-mail: giovanni.verzellesi@unimore.i [Fondazione Bruno Kessler (FBK), Trento (Italy)

    2009-11-15

    In this paper we propose a portable instrument for alpha-particle detection based on a previously-developed BJT detector and a simple, IC-based readout electronics. Experimental tests of the BJT detector and readout electronics are reported. Numerical simulations are adopted to predict the performance enhancement achievable with optimized BJT detectors.

  8. Alpha-particle detection based on the BJT detector and simple, IC-based readout electronics

    International Nuclear Information System (INIS)

    Rovati, L; Bonaiuti, M; Bettarini, S; Bosisio, L; Dalla Betta, G-F; Tyzhnevyi, V; Verzellesi, G; Zorzi, N

    2009-01-01

    In this paper we propose a portable instrument for alpha-particle detection based on a previously-developed BJT detector and a simple, IC-based readout electronics. Experimental tests of the BJT detector and readout electronics are reported. Numerical simulations are adopted to predict the performance enhancement achievable with optimized BJT detectors.

  9. Alpha particle effects as a test domain for PAP, a Plasma Apprentice Program

    International Nuclear Information System (INIS)

    Mynick, H.E.

    1987-01-01

    A new type of computational tool under development, employing techniques of symbolic computation and artificial intelligence to automate as far as possible the research activities of a human plasma theorist, is described. Its present and potential uses are illustrated using the area of the theory of alpha particle effects in fusion plasmas as a sample domain. (orig.)

  10. A Strange Box and a Stubborn Brit: Rutherford's Experiments with Alpha Particles.

    Science.gov (United States)

    Digilov, M.

    1991-01-01

    Discusses 5 innovative experiments conducted by Rutherford in early 1900s utilizing the 30 milligrams of radium salt he personally carried from Europe to Canada in 1903. Traces his work with alpha particles from his original results which determined their nature, charge, and mass, to his technique of backscattering which helped to advance…

  11. Quality assurance of alpha-particle dosimetry using peeled-off Gafchromic EBT3® film

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Chun, S.L.; Yu, K.N.

    2016-01-01

    A novel alpha-particle dosimetry technique using Gafchromic EBT3 film has recently been proposed for calibrating the activity of alpha-emitting radiopharmaceuticals. In the present paper, we outlined four measures which could further help assure the quality of the method. First, we suggested an alternative method in fabricating the peeled-off EBT3 film. Films with a chosen size were cut from the original films and all the edges were sealed with silicone. These were immersed into deionized water for 19 d and the polyester covers of the EBT3 films could then be easily peeled off. The active layers in these peeled-off EBT3 films remained intact, and these films could be prepared reproducibly with ease. Second, we proposed a check on the integrity of the peeled-off film by comparing the responses of the pristine and peeled-off EBT3 films to the same X-ray irradiation. Third, we highlighted the importance of scanning directions of the films. The “landscape” and “portrait” scanning directions were defined as the scanning directions perpendicular and parallel to the long edge of the original EBT3 films, respectively. Our results showed that the responses were different for different scanning directions. As such, the same scanning direction should be used every time. Finally, we cautioned the need to confirm the uniformity of the alpha-particle source used for calibration. Radiochromic films are well known for their capability of providing two-dimensional dosimetric information. As such, EBT3 films could also be conveniently used to check the uniformity of the alpha-particle source. - Highlights: • Proposed method to fabricate peeled-off EBT3 films for alpha dosimetry. • Proposed integrity check of peeled-off EBT3 films using X-ray irradiation. • Highlighted importance of scanning directions of EBT3 films. • Cautioned the need for uniformity check on alpha-particle source.

  12. Time evolution of a system of two alpha particles

    International Nuclear Information System (INIS)

    Baye, D.; Herschkowitz, D.

    1996-01-01

    Motivated by interpretations of a broad structure at 32.5 MeV in the 12 C( 12 C, 12 C(0 + 2 )) 12 C(0 + 2 ) doubly inelastic scattering cross sections in terms of linear chains of α particles, we study in a microscopic model with an exact account of antisymmetrization the time evolution of a system of two α clusters. The evolution of the system is obtained from a time-dependent variational principle and visualized with matter densities. Even in the most favourable case, an initial two-cluster structure completely disappears in less than 2.10 -22 s. This result casts doubts on the observability of longer α chains. (orig.)

  13. Alpha Particles Induce Autophagy in Multiple Myeloma Cells.

    Science.gov (United States)

    Gorin, Jean-Baptiste; Gouard, Sébastien; Ménager, Jérémie; Morgenstern, Alfred; Bruchertseifer, Frank; Faivre-Chauvet, Alain; Guilloux, Yannick; Chérel, Michel; Davodeau, François; Gaschet, Joëlle

    2015-01-01

    Radiation emitted by the radionuclides in radioimmunotherapy (RIT) approaches induce direct killing of the targeted cells as well as indirect killing through the bystander effect. Our research group is dedicated to the development of α-RIT, i.e., RIT using α-particles especially for the treatment of multiple myeloma (MM). γ-irradiation and β-irradiation have been shown to trigger apoptosis in tumor cells. Cell death mode induced by (213)Bi α-irradiation appears more controversial. We therefore decided to investigate the effects of (213)Bi on MM cell radiobiology, notably cell death mechanisms as well as tumor cell immunogenicity after irradiation. Murine 5T33 and human LP-1 MM cell lines were used to study the effects of such α-particles. We first examined the effects of (213)Bi on proliferation rate, double-strand DNA breaks, cell cycle, and cell death. Then, we investigated autophagy after (213)Bi irradiation. Finally, a coculture of dendritic cells (DCs) with irradiated tumor cells or their culture media was performed to test whether it would induce DC activation. We showed that (213)Bi induces DNA double-strand breaks, cell cycle arrest, and autophagy in both cell lines, but we detected only slight levels of early apoptosis within the 120 h following irradiation in 5T33 and LP-1. Inhibition of autophagy prevented (213)Bi-induced inhibition of proliferation in LP-1 suggesting that this mechanism is involved in cell death after irradiation. We then assessed the immunogenicity of irradiated cells and found that irradiated LP-1 can activate DC through the secretion of soluble factor(s); however, no increase in membrane or extracellular expression of danger-associated molecular patterns was observed after irradiation. This study demonstrates that (213)Bi induces mainly necrosis in MM cells, low levels of apoptosis, and autophagy that might be involved in tumor cell death.

  14. Alpha-particles induce autophagy in multiple myeloma cells

    Directory of Open Access Journals (Sweden)

    Joelle Marcelle Gaschet

    2015-10-01

    Full Text Available Objectives: Radiations emitted by the radionuclides in radioimmunotherapy (RIT approaches induce direct killing of the targeted cells as well as indirect killing through bystander effect. Our research group is dedicated to the development of α-RIT, i.e RIT using α-particles especially for the treatment of multiple myeloma (MM. γ-irradiation and β-irradiation have been shown to trigger apoptosis in tumor cells. Cell death mode induced by 213Bi α-irradiation appears more controversial. We therefore decided to investigate the effects of 213Bi on MM cell radiobiology, notably cell death mechanisms as well as tumor cell immunogenicity after irradiation.Methods: Murine 5T33 and human LP-1 multiple myeloma (MM cell lines were used to study the effects of such α-particles. We first examined the effects of 213Bi on proliferation rate, double strand DNA breaks, cell cycle and cell death. Then, we investigated autophagy after 213Bi irradiation. Finally, a co-culture of dendritic cells (DC with irradiated tumour cells or their culture media was performed to test whether it would induce DC activation.Results: We showed that 213Bi induces DNA double strand breaks, cell cycle arrest and autophagy in both cell lines but we detected only slight levels of early apoptosis within the 120 hours following irradiation in 5T33 and LP-1. Inhibition of autophagy prevented 213Bi induced inhibition of proliferation in LP-1 suggesting that this mechanism is involved in cell death after irradiation. We then assessed the immunogenicity of irradiated cells and found that irradiated LP-1 can activate DC through the secretion of soluble factor(s, however no increase in membrane or extracellular expression of danger associated molecular patterns (DAMPs was observed after irradiation.Conclusion: This study demonstrates that 213Bi induces mainly necrosis in MM cells, low levels of apoptosis and also autophagy that might be involved in tumor cell death.

  15. Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos

    Directory of Open Access Journals (Sweden)

    Candy Yuen Ping Ng

    2017-02-01

    Full Text Available Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf revealed through acridine orange (AO staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy and alpha-particle (4.4 mGy exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis.

  16. Study on Characteristic of CdZnTe Semiconductor Detectors for Alpha Particle Measurement

    International Nuclear Information System (INIS)

    Kang, Sang Mook; Ha, Jang Ho; Kim, Yong Kyun; Park, Se Hwan; Kim, Han Soo; Chung, Chong Eun

    2005-01-01

    The last 2-3 years have seen continued effort in the development of a wide band gap room-temperature compound semiconductor devices aimed principally at photon imaging covering hard X-rays, synchrotrons, and low to medium energy gamma rays. Especially, among the semiconductor materials of a wide band gap, CdZnTe(CZT) has commonly used X-ray and gammaray detection applications because of the opportunity to achieve and excellent spectral and spatial resolution. It has recently been demonstrated that CZT can be used as an ancillary detector with the ability to detect both alpha particles and X-ray at room temperature. CZT detectors are relatively inexpensive compared with some silicon detectors, and are priced about the same as amorphous silicon and photodiodes which are routinely used for charged particle detection. In this paper, we investigated the use of the CZT semiconductor material as an alpha particles detector

  17. Bystander effect of alpha-particle irradiation on mutagenicity and its associated mechanism

    International Nuclear Information System (INIS)

    Lu Ying; Yang Zhihua; Cao Zhenshan; Fan Feiyue; Zhu Maoxiang

    2004-01-01

    The work is to investigate α-particle irradiation-induced bystander effects on the mutagenicity in human chromosome 11 in the human-hamster hybrid (A L cells) and its possible mechanism. A L cells were used for assaying mutation rates of human chromosome 11 through screening mutants in the presence of anti-CD59 surface antigen antibody (S1) and complement. A grid was interposed between α-particle source and the cells being irradiated, so as to fix proportion of the irradiated cells (15%) and the bystander effects on the mutagenicity were detected. Free radical scavenger DMSO and intercellular communication inhibitor Lindane were selected to investigate the potential mechanism of α-particle induced bystander effect. There was clear dose-dependent relationship between mutation rate and the dose of alpha particle radiation. However, the mutant fractions of cell population shielded by the grid in α-particle irradiation system were much higher than the expected levels of irradiated cells. Lindane, but not DMSO, could obviously decrease this bystander effect induced by α-particle irradiation. Alpha-particle irradiation can induce bystander effect on the mutagenicity, in which intercellular communication may play important roles

  18. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles.

    Science.gov (United States)

    Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Amin, Yusoff Mohd

    2015-05-21

    Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA) acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0-20 min) of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung's and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung's methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.

  19. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles

    Directory of Open Access Journals (Sweden)

    Hassan Maktuff Jaber Al-Ta'ii

    2015-05-01

    Full Text Available Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0–20 min of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung’s and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung’s methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.

  20. Measurement of {alpha} particle energy loss in biological tissue below 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Stella, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy); Bortolussi, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy)], E-mail: silva.bortolussi@pv.infn.it; Bruschi, P.; Portella, C. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); Altieri, S. [Department of Nuclear and Theoretical Physics, University of Pavia, Pavia (Italy); National Institute of Nuclear Physics (INFN), Pavia (Italy)

    2009-09-01

    The energy loss of {alpha} particles crossing biological tissue at energies between 0.8 and 2.2 MeV has been measured. This energy range is very important for boron neutron capture therapy, based on the {sup 10}B(n,{alpha}){sup 7}Li reaction, which emits {alpha} particles with energies of 1.78 and 1.47 MeV. One of the methods used for the measurement of the boron concentration in tissue is based on the deconvolution of the {alpha} spectra obtained from neutron irradiation of thin (70 {mu}m) tissue samples. For this technique, a knowledge of the behaviour of the energy loss of the particles in the irradiated tissue is of critical importance. In particular, the curve of the residual energy as a function of the distance travelled in the tissue must be known. In this paper, the results of an experiment carried out with an {sup 241}Am source and a series of cryostatic sections of rat-lung tissue are presented. The experimental measurements are compared with the results of Monte Carlo calculations performed with the MCNPX code.

  1. Angular correlation between short-range. cap alpha. particles and. gamma. quanta

    Energy Technology Data Exchange (ETDEWEB)

    Kul' chitskii, L A; Latyshev, G D; Bulyginskii, D G

    1949-01-01

    Chang (Phys. Rev. 69, 60(1946); 70, 632(1946)) has found that the intensities of short-range ..cap alpha.. rays of Po and Ra are considerably higher than the values given by the Geiger-Nuttall law. This can be explained by assuming surface vibrations of ..cap alpha..-radioactive nuclei, which produce deformations and corresponding lowerings of the potential barrier in certain directions. In this case an angular correlation should exist between the short-range ..cap alpha.. ray and the accompanying ..gamma.. quantum. The authors checked this conclusion by applying the coincidence method to the ..cap alpha.. and ..gamma.. radiations of a mixture of RdTh (/sup 228/Th) and ThC (/sup 212/Bi). Maxima of coincidence numbers occur at angles 45 and 135 deg., with lesser maxima at 0 and 180 deg. Theoretical considerations show that in cases (like the one investigated) where the nuclear spin before and after the ..cap alpha.. and ..gamma.. emissions is zero, the angular correlations are uniquely determined whatever the deformation caused by the vibration; in other cases, the correlation depends on the kind of deformation. Therefore, it would be interesting to investigate the case of Pa, whose nuclear spin is not zero and the decay exhibits intensive groups of short-range ..cap alpha.. particles.

  2. Human cytogenetic dosimetry: a dose-response relationship for alpha particle radiation from 241Am

    International Nuclear Information System (INIS)

    DuFrain, R.J.; Littlefield, L.G.; Joiner, E.E.; Frome, E.L.

    1979-01-01

    Cytogenetic dosimetry estimates to guide treatment of persons internally contaminated with transuranic elements have not previously been possible because appropriate in vitro dose-response curves specifically for alpha particle irradiation of human lymphocytes do not exist. Using well-controlled cytogenetic methods for human lymphocyte culture, an experimentally derived dose-response curve for 241 Am alpha particle (5.49 and 5.44 MeV) radiation of G 0 lymphocytes was generated. Cells were exposed to 43.8, 87.7, 175.3 or 350.6 nCi/ml 241 Am for 1.7 hr giving doses of 0.85, 1.71, 3.42 or 6.84 rad. Based on dicentric chromosome yield, the linear dose-response equation is Y = 4.90(+-0.42) x 10 -2 X, with Y given as dicentrics per cell and X as dose in rads. The study also shows that the two-break asymmetrical exchanges in cells damaged by alpha particle radiation are overdispersed when compared to a Poisson distribution. An example is presented to show how the derived dose-response equation can be used to estimate the radiation dose for a person internally contaminated with an actinide. An experimentally derived RBE value of 118 at 0.85 rad is calculated for the efficiency of 241 Am alpha particle induction of dicentric chromosomes in human G 0 lymphocytes as compared with the efficiency of 60 Co gamma radiation. The maximum theoretical value for the RBE for cytogenetic damage from alpha irradiation was determined to be 278 at 0.1 rad or less which is in marked contrast to previously reported RBE values of approx. 20. (author)

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

    Science.gov (United States)

    Watchman, Christopher J.

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

  4. New measurements of W-values for protons and alpha particles

    International Nuclear Information System (INIS)

    Giesen, U.; Beck, J.

    2014-01-01

    The increasing importance of ion beams in cancer therapy and the lack of experimental data for W-values for protons and heavy ions in air require new measurements. A new experimental set-up was developed at PTB and consistent measurements of W-values in argon, nitrogen and air for protons and alpha particles with energies from 0.7 to 3.5 MeV u -1 at PTB, and for carbon ions between 3.6 and 7.0 MeV u -1 at GSI were carried out. This publication concentrates on the measurements with protons and alpha particles at PTB. The experimental methods and the determination of corrections for recombination effects, beam-induced background radiation and additional effects are presented. W-values in argon, nitrogen and air were measured for protons with energies of 1-3 MeV and for alpha particles with energies of 2.7-14 MeV. The energies of the primary particle beam were corrected for energy losses in the gold and Mylar foils, as well as for the kinematic energy loss due to scattering by 45 deg.. Beam-induced radiation backgrounds as well as recombination effects were determined and corrected for. The present results are summarised in Figure 2 for all three gases. The solid lines through the data points for each gas indicate an average W-value for that gas. The higher values for 2.7-MeV alpha particles agree with the trend in previous data towards lower energies. They are excluded from the averages. The relative standard uncertainties of the individual data points range from 1.3 to 3 %. The weighted averages over all energies are W(Ar) = 25.7 eV, W(N 2 ) = 35.6 eV and W(Air) = 34.2 eV. The averages serve as a first comparison and the lines on the plot are to guide the eye and are not meant to imply constant W-values for all energies and particles. The W-values for protons and alpha particles in argon and nitrogen have smaller uncertainties and are lower than the suggested values, but they are still in agreement within the uncertainties. For alpha particles with energies of 12

  5. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    Energy Technology Data Exchange (ETDEWEB)

    Lyckesvärd, Madeleine Nordén, E-mail: madeleine.lyckesvard@oncology.gu.se [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Delle, Ulla; Kahu, Helena [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Lindegren, Sture [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Jensen, Holger [The PET and Cyclotron Unit Copenhagen University Hospital, Rigshospitalet (Denmark); Bäck, Tom [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Swanpalmer, John [Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden); Elmroth, Kecke [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden)

    2014-07-15

    Highlights: • We study DNA damage response to low-LET photons and high-LET alpha particles. • Cycling primary thyrocytes are more sensitive to radiation than stationary cells. • Influence of radiation quality varies due to cell cycle status of normal cells. • High-LET radiation gives rise to a sustained DNA damage response. - Abstract: Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ({sup 211}At), concentrated in the thyroid by the same mechanism as {sup 131}I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ({sup 60}Co) and alpha particles from {sup 211}At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity levels of γH2AX decreased during the first 24 h in both cycling and stationary cultures and complete repair was seen in all cultures but cycling cells exposed to {sup 211}At. Compared to stationary cells alpha particles were more harmful for cycling cultures, an effect also seen at the pChk2 levels. Increasing ratios of micronuclei per cell nuclei were seen up to 1 Gy {sup 211}At. We found that primary thyrocytes were much more sensitive to alpha particle exposure compared with low-LET photons. Calculations of the relative biological effectiveness yielded higher RBE for cycling cells compared with stationary cultures at a modest level of damage, clearly demonstrating that cell cycle status influences the relative

  6. Destabilization of low mode number Alfven modes in a tokamak by energetic or alpha particles

    International Nuclear Information System (INIS)

    Tsang, K.T.; Sigmar, D.J.; Whitson, J.C.

    1980-12-01

    With the inclusion of finite Larmor radius effects in the shear Alfven eigenmode equation, the continuous Alfven spectrum, which has been extensively discussed in ideal magnetohydrodynamics, is removed. Neutrally stable, discrete radial eigenmodes appear in the absence of sources of free energy and dissipation. Alpha (or energetic) particle toroidal drifts destabilize these modes, provided the particles are faster than the Alfven speed. Although the electron Landu resonance contributes to damping, a stability study of the parametric variation of the energy and the density scale length of the energetic particles shows that modes with low radial mode numbers remain unstable in most cases. Since the alpha particles are concentrated in the center of the plasma, this drift-type instability suggests anomalous helium ash diffusion. Indeed, it is shown that stochasticity of alpha orbits due to the overlapping of radially neighboring Alfven resonances is induced at low amplitudes, e/sub i//sup approx./phi/T/sub i/ greater than or equal to 0.05, implying a diffusion coefficient D/sub r//sup α/ greater than or equal to 4.4 x 10 3 cm 2 /s

  7. Bulk GaN alpha-particle detector with large depletion region and improved energy resolution

    Science.gov (United States)

    Xu, Qiang; Mulligan, Padhraic; Wang, Jinghui; Chuirazzi, William; Cao, Lei

    2017-03-01

    An alpha-particle detector was fabricated using a freestanding n-type bulk GaN wafer with a Au/Ni/GaN sandwich Schottky structure. Current-voltage measurements at room temperature revealed a Schottky contact with a leakage current of 7.53±0.3 nA at a reverse bias of 200 V. The detector had a large depletion depth that can capture much of the energy from 5.486 MeV alpha particles emitted from a 241Am source. The resolution of its alpha-particle energy spectrum was improved to 2.2±0.2% at 5.486 MeV under a bias of 550 V. This superior resolution was attributed to the shortening of the carrier transit time and the large energy deposition within the large depletion depth, i.e., 27 μm at -550 V, which all resulted in a more complete charge collection. A model developed using the ATLAS simulation framework from Silvaco Inc. was employed to study the charge collection process. The simulation results were found to agree closely with the experimental results. This detector will be beneficial for research at neutron scattering facilities, the International Thermonuclear Experimental Reactor, and the Large Hadron Collider, among other institutions, where the Si-based charged particle detectors could be quickly degraded in an intense radiation field.

  8. Photoluminescence detection of alpha particle using DAM-ADC nuclear detector

    Energy Technology Data Exchange (ETDEWEB)

    Abdalla, Ayman M., E-mail: aymanabdalla62@hotmail.com [Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box: 1988, Najran 11001 (Saudi Arabia); Harraz, Farid A., E-mail: fharraz68@yahoo.com [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box: 1988, Najran 11001 (Saudi Arabia); Nanostructured Materials and Nanotechnology Division, Central Metallurgical Research and Development Institute (CMRDI), P.O. Box: 87 Helwan, Cairo 11421 (Egypt); Ali, Atif M. [Department of Physics, Faculty of Science, King Khalid University, Abha (Saudi Arabia); Al-Sayari, S.A. [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box: 1988, Najran 11001 (Saudi Arabia); College of Science and Arts-Sharoura, Najran University (Saudi Arabia); Al-Hajry, A. [Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box: 1988, Najran 11001 (Saudi Arabia)

    2016-09-11

    The photoluminescence (PL) and UV–vis spectral analysis of DAM-ADC (diallyl maleate: DAM, polyallyl diglycol carbonate: ADC) nuclear detector are demonstrated for the first time. The DAM-ADC surfaces were exposed to thin {sup 241}Am disk source that emits alpha particles with activity 333 kBq. It is found that the track density of the irradiated samples remarkably influences the PL characteristics of the DAM-ADC detector. The spectral peak heights and the integrated intensities under the peaks exhibit linear correlations with correlation coefficient R{sup 2}=0.9636 and 0.9806, respectively for different alpha particle fluences ranging from 8.16–40.82×10{sup 7} particles/cm{sup 2}. Additionally, a correlation coefficient R{sup 2}=0.9734 was achieved for the UV–vis spectral analysis. The linear fitting functions, along with the corresponding fitting parameters were evaluated in each case. Both the PL and the UV–vis data of the irradiated DAM-ADC samples showed considerable spectral differences, and hence they would be used to offer sensitive approaches for alpha particle detection.

  9. Ionization and scintillation response of high-pressure xenon gas to alpha particles

    International Nuclear Information System (INIS)

    Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Gil, A; Gómez-Cadenas, J J; Borges, F I G; Conde, C A N; Fernandes, L M P; Freitas, E D C; Cebrián, S; Dafni, T; Gómez, H; Egorov, M; Gehman, V M; Goldschmidt, A; Esteve, R; Evtoukhovitch, P; Ferreira, A L

    2013-01-01

    High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the ionization and scintillation detection properties of xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. We measure the ionization electron drift velocity and longitudinal diffusion, and compare our results to expectations based on available electron scattering cross sections on pure xenon. In addition, two types of measurements addressing the connection between the ionization and scintillation yields are performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similar to that already observed in liquid xenon. On the other hand, we study the field dependence of the average scintillation and ionization yields. Both types of measurements may shed light on the mechanism of electron-ion recombination in xenon gas for highly-ionizing particles. Finally, by comparing the response of alpha particles and electrons in NEXT-DEMO, we find no evidence for quenching of the primary scintillation light produced by alpha particles in the xenon gas.

  10. Elastic and inelastic scattering of alpha particles from sup 46 Ti at E sub. alpha. = 35 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Raghunatha Rao, V.; Sudarshan, M.; Sarma, A.; Singh, R. (North-Eastern Hill Univ., Shillong (India). Dept. of Physics); Banerjee, S.R.; Chintalapudi, S.N. (Bhabha Atomic Research Centre, Bombay (India). Variable Energy Cyclotron Project)

    1991-12-01

    Differential cross sections for elastic and inelastic scattering of 35 MeV alpha particles have been measured from {theta}{sub lab} =10{sup o} to 100{sup o} in 1{sup o}-2{sup o} steps. An optical model analysis of the elastic scattering data has been carried out using Woods-Saxon and Woods-Saxon squared radial dependences for real as well as imaginary parts of the potential. The most sensitive region of the potential in predicting the elastic scattering cross sections has been determined using a notch perturbation test. The problem of discrete family ambiguity in the optical model analysis of elastic data has also been investigated. The inelastic scattering data have been analysed in terms of the collective model using the distorted-wave Born approximation (DWBA), where the distorted waves are generated by the optical potential obtained from the elastic scattering data. (author).

  11. Factors affecting the energy resolution in alpha particle spectrometry with silicon diodes

    International Nuclear Information System (INIS)

    Camargo, Fabio de.

    2005-01-01

    In this work are presented the studies about the response of a multi-structure guard rings silicon diode for detection and spectrometry of alpha particles. This ion-implanted diode (Al/p + /n/n + /Al) was processed out of 300 μm thick, n type substrate with a resistivity of 3 kΩ·cm and an active area of 4 mm 2 . In order to use this diode as a detector, the bias voltage was applied on the n + side, the first guard ring was grounded and the electrical signals were readout from the p + side. These signals were directly sent to a tailor made preamplifier, based on the hybrid circuit A250 (Amptek), followed by a conventional nuclear electronic. The results obtained with this system for the direct detection of alpha particles from 241 Am showed an excellent response stability with a high detection efficiency (≅ 100 %). The performance of this diode for alpha particle spectrometry was studied and it was prioritized the influence of the polarization voltage, the electronic noise, the temperature and the source-diode distance on the energy resolution. The results showed that the major contribution for the deterioration of this parameter is due to the diode dead layer thickness (1 μm). However, even at room temperature, the energy resolution (FWHM = 18.8 keV) measured for the 5485.6 MeV alpha particles ( 241 Am) is comparable to those obtained with ordinary silicon barrier detectors frequently used for these particles spectrometry. (author)

  12. Simulation study for high resolution alpha particle spectrometry with mesh type collimator

    International Nuclear Information System (INIS)

    Park, Seunghoon; Kwak, Sungwoo; Kang, Hanbyeol; Shin, Jungki; Park, Iljin

    2014-01-01

    An alpha particle spectrometry with a mesh type collimator plays a crucial role in identifying specific radionuclide in a radioactive source collected from the atmosphere or environment. The energy resolution is degraded without collimation because particles with a high angle have a longer path to travel in the air. Therefore, collision with the background increases. The collimator can cut out particles which traveling at a high angle. As a result, an energy distribution with high resolution can be obtained. Therefore, the mesh type collimator is simulated for high resolution alpha particle spectrometry. In conclusion, the collimator can improve resolution. With collimator, the collimator is a role of cutting out particles with a high angle, so, low energy tail and broadened energy distribution can be reduced. The mesh diameter is found out as an important factor to control resolution and counting efficiency. Therefore, a target particle, for example, 235 U, can be distinguished by a detector with a collimator under a mixture of various nuclides, for example: 232 U, 238 U, and 232 Th

  13. Cryogenic microcalorimeter system for ultra-high resolution alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Rabin, Michael W.; Hoover, Andrew S.; Bacrania, Minesh K.; Croce, Mark P.; Hoteling, N.J.; Lamont, S.P.; Plionis, A.A.; Dry, D.E.; Ullom, J.N.; Bennett, D.A.; Horansky, R.; Kotsubo, V.; Cantor, R.

    2009-01-01

    Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ∼15 uK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis, This paper will discuss design and operation of our microcalorimeter alpha spectrometer, and will show recent results.

  14. Calibration of the polycarbonate dosimeter for the microdosimetry of 239Pu alpha particles in bone

    International Nuclear Information System (INIS)

    Stillwagon, G.B.; Morgan, K.Z.

    1977-01-01

    There has been some criticisms of the maximum permissible organ burden (MPOB) in bone for 239 Pu in recent years. These criticisms allude to the relative dearth of experimental data available concerning the actual dose delivered to the endosteal face of osseous tissue by the 239 Pu alpha particle. A dosimeter recently developed has been recommended for application to this microdosimetry problem. The tissue equivalence of polycarbonate dosimeters would allow dose equivalent to be read directly from the foil rather than determining activity from emulsions, in which the alpha particle range is different than in tissue, then relating this activity measurement to absorbed dose by some calculations. Although this dosimeter has been calibrated to read dose equivalent for fast neutron dosimetry, the need exists to determine the factor to multiply by the number of 239 Pu alpha-induced tracks to obtain dose equivalent. This problem is being approached in the following manner. A device called the vacuum-sealed alpha-calibrator has been designed and constructed which will allow the handling of a standard 239 Pu solution obtained for this purpose. The calibrator will first be connected to surface barrier detectors which feed data into a multi-channel analyzer. The counts obtained under the alpha peaks at various heights above the source and the accumulated time are input into a computer program recently written to convert this data into dose rate in rems/unit time. Next the measurements are duplicated, this time using the polycarbonate dosimeter. The results will produce a factor relating the number of alpha-induced tracks to dose

  15. Measurement of airborne concentrations of radon-220 daughter products by alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Kerr, G.D.; Ryan, M.T.; Perdue, P.T.

    1978-01-01

    The decay of naturally occurring uranium-238 and thorium-232 produces radon-222 and radon-220 isotopes which can escape into the atmosphere. If these radon gases become concentrated in air, their daughter products may present an inhalation hazard to man. The airborne concentrations of radon-222 can usually be measured very accurately in the presence of normal airborne concentrations of radon-220 and its daughters. In contrast, the measurements of the airborne concentrations of radon-220 daughters are usually complicated by the presence of radon-222 and its daughters even at normally occurring airborne concentrations. The complications involved in these measurements can be overcome in most situations by using an alpha particle spectrometer to distinguish the activity of radon-222 daughters from that due to radon-220 daughters collected on a filter. A practical spectrometer for field measurements of alpha particle activity on a filter is discussed

  16. Survival of human osteosarcoma cells and normal human fibroblasts following alpha particle irradiation

    International Nuclear Information System (INIS)

    Lloyd, E.L.; Gemmell, M.A.

    1981-01-01

    Cell survival of human osteosarcoma cells in culture following alpha particle irradiation is reported here for the first time. The osteosarcoma cell line (TE-85) is found to be less sensitive to inactivation by 5.6 MeV alpha particles (LET 86 keV/μm) than normal diploid human fibroblasts (NFS). Values for the mean lethal doses were estimated to be 103 rads for the TE-85 cells compared with 68 rads for the NFS cultures irradiated under identical conditions. It is postulated that the aneuploidy of the tumor cells with increased DNA chromosomal material may confer a selective advantage for the survival of tumor cells relative to normal cells with diploid chromosomes

  17. An experimental study of symmetric and asymmetric peak-fitting parameters for alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Martin Sanchez, A.; Vera Tome, F.; Caceres Marzal, D.; Bland, C.J.

    1994-01-01

    A pulse-height spectrum of alpha-particle emissions at discrete energies can be fitted by the peak-shape functions generated by combining asymmetric truncated exponential functions with a symmetric Gaussian distribution. These functions have been applied successfully by several workers. A correlation was previously found between the variance of the symmetric Gaussian portion of the fitting function, and the parameter characterising the principal exponential tailing function. The results of a more detailed experimental study are reported, which involve varying the angle and the distance between the source and the detector. This analysis shows that the parameters of the symmetric and asymmetric parts of the fitted functions seem to depend on either the detector or the source. These parameters are influenced by the energy loss suffered by the alpha-particles as well as by the efficiency of charge collection in the solid-state detector. (orig.)

  18. Technique for measuring the losses of alpha particles to the wall in TFTR

    International Nuclear Information System (INIS)

    England, A.C.

    1984-03-01

    It is proposed to measure the losses of alpha particles to the wall in the Tokamak Fusion Test Reactor (TFTR) or any large deuterium-tritium (D-T) burning tokamak by a nuclear technique. For this purpose, a chamber containing a suitable fluid would be mounted near the wall of the tokamak. Alpha particles would enter the chamber through a thin window and cause nuclear reactions in the fluid. The material would then be transported through a tube to a remote, low-background location for measurement of the activity. The most favorable reaction suggested here is 10 B(α,n) 13 N, although 14 N(α,γ) 18 F and others may be possible. The system, the sensitivity, the probe design, and the sources of error are described

  19. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    DEFF Research Database (Denmark)

    Lyckesvärd, Madeleine Nordén; Delle, Ulla; Kahu, Helena

    2014-01-01

    Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ((211)At), concentrated in the thyroid by the same...... mechanism as (131)I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation...... and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ((60)Co) and alpha particles from (211)At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity...

  20. GAMCAT - a personal computer database on alpha particles and gamma rays from radioactive decay

    International Nuclear Information System (INIS)

    Tepel, J.W.; Mueller, H.W.

    1990-01-01

    The GAMCAT database is a compilation of data describing the alpha particles and gamma rays that occur in the radioactive decay of all known nuclides, adapted for IBM Personal Computers and compatible systems. These compiled data have been previously published, and are now available as a compact database. Entries can be retrieved by defining the properties of the parent nuclei as well as alpha-particle and gamma-ray energies or any combination of these parameters. The system provides fast access to the data and has been completely written in C to run on an AT-compatible computer, with a hard disk and 640K of memory under DOS 2.11 or higher. GAMCAT is available from the Fachinformationszentrum Karlsruhe. (orig.)

  1. Slowing down tail enhanced, neoclassical and classical alpha particle fluxes in tokamak reactors

    International Nuclear Information System (INIS)

    Catto, P.J.; Tessarotto, M.

    1988-01-01

    The classical and neoclassical particle and energy fluxes associated with a slowing down tail, alpha particle distribution function are evaluated for arbitrary aspect ratio ε -1 , cross section, and poloidal magnetic field. The retention of both electron and ion drag and pitch angle scattering by the background ions results in a large diffusive neoclassical heat flux in the plasma core. This flux remains substantial at larger radii only if the characteristic speed associated with pitch angle scattering, v/sub b/, is close enough to the alpha birth speed v 0 so that ε(v 0 /v/sub b/) 3 remains less than some order unity critical value which is not determined by the methods herein. The enhanced neoclassical losses would only have a serious impact on ignition if the critical value of ε(v 0 /v/sub b/) 3 is found to be somewhat larger than unity

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

    International Nuclear Information System (INIS)

    Aratani, Michi; Otsuka, Hideko

    1975-01-01

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

  3. Alpha particle spectra in coincidence with normal and superdeformed states in {sup 150}Tb

    Energy Technology Data Exchange (ETDEWEB)

    Viesti, G.; Lunardon, M.; Bazzacco, D. [dell`Universita, Padova (Italy)]|[INFN, Padova (Italy)] [and others

    1996-12-31

    The study of correlations between particle evaporation from highly excited compound nuclei at large angular momenta and the states in the final evaporation residues (ER) is a field of investigation which has been opened, in the last years, with the advent of the new large {gamma}-ray arrays. It is now possible to correlate the evaporation spectra to various bands with shapes ranging from spherical to superdeformed (SD) in the same final nucleus. It is generally accepted that the particle evaporation from the compound nucleus is chaotic and that only in the near-yrast {gamma} cascade, where the feeding of different classes of states takes place, the ordered motion is restored. The sensitivity of the particle spectra on the feeding of specific states in the residual nuclei can be taken as an indication that additional degrees of freedom might be important in the evaporation process or that particular regions of the phase space open to the decay populate preferentially some selected structures in the final cold nucleus. This latter point is important for the understanding of the feeding mechanism of SD states. Several experiments performed so far did not find a clear dependence of the shapes of the particle spectra on the excited states having different deformations in the ER. For example, the proton spectra in coincidence with transitions in the SD bands of {sup 133}Nd and {sup 152}Dy nuclei were found to be similar to those in coincidence with transitions in the normal deformed (ND) bands. Alpha particles have been proposed since long as a sensitive probe of the deformation of the emitting nucleus. Results are presented here of an experiment in which the authors have measured the energy spectra of alpha particles associated with different classes of states (ND and SD) in the {sup 150}Tb nucleus populated in the reaction {sup 37}Cl({sup 120}Sn, {alpha}3n{gamma}){sup 150}Tb.

  4. Operation of a high-purity silicon diode alpha particle detector at 1. 4 K

    Energy Technology Data Exchange (ETDEWEB)

    Martoff, C.J.; Kaczanowicz, E. (Temple Univ., Philadelphia, PA (USA)); Neuhauser, B.J.; Lopez, E.; Zhang, Y. (San Francisco State Univ., CA (USA)); Ziemba, F.P. (Quantrad Corp. (USA))

    1991-03-01

    Detection of alpha particles at temperatures as low as 1.4 K was demonstrated using a specially fabricated Si diode. The diode was 475 mm{sup 2} by 0.280 mm thick, fabricated from high-purity silicon with degenerately doped contacts. This is an important step toward development of dual-mode (ionization plus phonon) silicon detectors for low energy radiation. (orig.).

  5. Data needs for the track structure of alpha particles and electrons in water

    International Nuclear Information System (INIS)

    Pagnamenta, A.

    1983-01-01

    We have made calculations of the ionization spectra for alpha particle and electron tracks in water. We have also computed the number of ions created per micrometre of track length, the energy distribution of the secondaries, and the energy expended per ion pair created. Our aim is less toward theoretical derivations than to obtain a numerically accurate description of the track structure at all energies in a form suitable for biomedical applications. 13 references

  6. The use of silicon devices (diodes, RAMs, etc.) for alpha particle detection

    International Nuclear Information System (INIS)

    Agosteo, S.; Foglio Para, A.

    1993-01-01

    Silicon electronic devices (diodes, random access memories (RAMs), etc.) can be employed in alpha particle detection and spectroscopy with a good energy resolution. The detection mechanisms are first discussed; the performances of these devices operating in the pulse and in the current mode are then described starting from the pioneering works of the last decade. Some peculiar applications of RAMs are finally reported. (author). 7 refs, 5 figs, 1 tab

  7. BJT detector with FPGA-based read-out for alpha particle monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Tyzhnevyi, V; Dalla Betta, G-F [Universita di Trento, via Sommarive, 14, 38123 Trento (Italy); Rovati, L [Universita di Modena e Reggio Emilia, via Vignolese 905, 41125 Modena (Italy); Verzellesi, G [Universita di Modena e Reggio Emilia, via Amendola 2, Pad. Morselli, 42100 Reggio Emilia (Italy); Zorzi, N, E-mail: tyzhnevyi@disi.unitn.it [Fondazione Bruno Kessler, via Sommarive, 18, 38123 Trento (Italy)

    2011-01-15

    In this work we introduce a new prototype of readout electronics (ALPHADET), which was designed for an {alpha}-particle detection system based on a bipolar junction transistor (BJT) detector. The system uses an FPGA, which provides many advantages at the stage of prototyping and testing the detector. The main design and electrical features of the board are discussed in this paper, along with selected results from the characterization of ALPHADET coupled to BJT detectors.

  8. Sporadic error probability due to alpha particles in dynamic memories of various technologies

    International Nuclear Information System (INIS)

    Edwards, D.G.

    1980-01-01

    The sensitivity of MOS memory components to errors induced by alpha particles is expected to increase with integration level. The soft error rate of a 65-kbit VMOS memory has been compared experimentally with that of three field-proven 16-kbit designs. The technological and design advantages of the VMOS RAM ensure an error rate which is lower than those of the 16-kbit memories. Calculation of the error probability for the 65-kbit RAM and comparison with the measurements show that for large duty cycles single particle hits lead to sensing errors and for small duty cycles cell errors caused by multiple hits predominate. (Auth.)

  9. Detection of fission fragments and alpha particles using the solid trace detector CR-39

    International Nuclear Information System (INIS)

    Santos, R.C.

    1988-01-01

    The technique of detecting charged particles using the solid track detector CR-39 is employed to establish some characteristics of fission fragments and alpha particles emitted from a Cf-252 source. Results are presented and discussed on the following aspects i) distribution of the track diameters; ii) variations on the track diameters to the chemical attack; iii) variations of the chemical attack velocity with respect to concentration and temperature. iv) activation energy of the developping process; v) induction time; vi) critical angle and efficiency on track developping. (A.C.A.S.) [pt

  10. ALFITeX. A new code for the deconvolution of complex alpha-particle spectra

    International Nuclear Information System (INIS)

    Caro Marroyo, B.; Martin Sanchez, A.; Jurado Vargas, M.

    2013-01-01

    A new code for the deconvolution of complex alpha-particle spectra has been developed. The ALFITeX code is written in Visual Basic for Microsoft Office Excel 2010 spreadsheets, incorporating several features aimed at making it a fast, robust and useful tool with a user-friendly interface. The deconvolution procedure is based on the Levenberg-Marquardt algorithm, with the curve fitting the experimental data being the mathematical function formed by the convolution of a Gaussian with two left-handed exponentials in the low-energy-tail region. The code also includes the capability of fitting a possible constant background contribution. The application of the singular value decomposition method for matrix inversion permits the fit of any kind of alpha-particle spectra, even those presenting singularities or an ill-conditioned curvature matrix. ALFITeX has been checked with its application to the deconvolution and the calculation of the alpha-particle emission probabilities of 239 Pu, 241 Am and 235 U. (author)

  11. Revisiting alpha decay-based near-light-speed particle propulsion

    International Nuclear Information System (INIS)

    Zhang, Wenwu; Liu, Zhen; Yang, Yang; Du, Shiyu

    2016-01-01

    Interplanet and interstellar travels require long-term propulsion of spacecrafts, whereas the conventional schemes of propulsion are limited by the velocity of the ejected mass. In this study, alpha particles released by nuclear decay are considered as a potential solution for long-time acceleration. The principle of near-light-speed particle propulsion (NcPP) was elucidated and the stopping and range of ions in matter (SRIM) was used to predict theoretical accelerations. The results show that NcPP by means of alpha decay is feasible for long-term spacecraft propulsion and posture adjustment in space. A practical NcPP sail can achieve a speed >150 km/s and reach the brink of the solar system faster than a mass equivalent solar sail. Finally, to significantly improve the NcPP sail, the hypothesis of stimulated acceleration of nuclear decay (SAND) was proposed, which may shorten the travel time to Mars to within 20 days. - Highlights: • SRIM was used to study the alpha particle penetration depth and efficiency. • Correlation between thickness of decayable foil and propulsion force was established. • With the hypothesis of SAND, the travel time to Mars may be shortened to <20 days.

  12. ALPHACAL: A new user-friendly tool for the calibration of alpha-particle sources.

    Science.gov (United States)

    Timón, A Fernández; Vargas, M Jurado; Gallardo, P Álvarez; Sánchez-Oro, J; Peralta, L

    2018-05-01

    In this work, we present and describe the program ALPHACAL, specifically developed for the calibration of alpha-particle sources. It is therefore more user-friendly and less time-consuming than multipurpose codes developed for a wide range of applications. The program is based on the recently developed code AlfaMC, which simulates specifically the transport of alpha particles. Both cylindrical and point sources mounted on the surface of polished backings can be simulated, as is the convention in experimental measurements of alpha-particle sources. In addition to the efficiency calculation and determination of the backscattering coefficient, some additional tools are available to the user, like the visualization of energy spectrum, use of energy cut-off or low-energy tail corrections. ALPHACAL has been implemented in C++ language using QT library, so it is available for Windows, MacOs and Linux platforms. It is free and can be provided under request to the authors. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Rapid appearance of transient secondary adrenocortical insufficiency after alpha-particle radiation therapy for Cushing's disease

    International Nuclear Information System (INIS)

    Cook, D.M.; Jordan, R.M.; Kendall, J.W.; Linfoot, J.A.

    1976-01-01

    A 17-year-old woman received 12,000 rads of alpha-particle radiation for the treatment of Cushing's disease. One day after the completion of therapy, the patient developed nausea, vomiting, headache, and postural hypotension. Laboratory evaluation demonstrated a marked fall of the previously elevated urinary 17-hydroxycorticosteroids (17-OHCS) and undetectable plasma cortisols. The urinary 17-OHCS transiently returned to supranormal levels but over a 2 1 / 2 -week period decreased and then remained low. The patient also demonstrated a subnormal urinary aldosterone excretion in relation to plasma renin activity (PRA) during 10 mEq/24 h sodium restriction. The remainder of the endocrine evaluation was normal, suggesting that pituitary function otherwise remained intact. One and one-half years after alpha-particle therapy, the patient's urinary 17-OHCS were normal and responded normally to metyrapone. The relationship between urinary aldosterone excretion and PRA also was normal. It is postulated that there was an infarction of an ACTH secreting pituitary tumor leaving the remainder of the pituitary intact. A chronically elevated circulating level of ACTH with sudden loss of ACTH secretion appeared to have been responsible for the initial low urinary aldosterone as well as the low urinary 17-OHCS. This is the first reported case of a presumed pituitary tumor infarction in association with alpha-particle pituitary radiation

  14. Characterization of actinide targets by low solid-angle alpha particle counting

    CERN Document Server

    Denecke, B; Pauwels, J; Robouch, P; Gilliam, D M; Hodge, P; Hutchinson, J M R; Nico, J S

    1999-01-01

    Actinide samples were characterized in an interlaboratory comparison between IRMM and NIST, including alpha-particle counting at defined low solid angle and counting in a 2 pi proportional gas counter. For this comparison, nine sup 2 sup 3 sup 3 UF sub 4 samples with high uniformity in the layer thickness were prepared at IRMM by deposition under vacuum. Polished silicon wafers were used as source substrates, and these were rotated during the deposition using a planetary rotation system. The estimated uncertainties for the defined low solid-angle methods were about 0.1% at both NIST and IRMM. The agreement of reported alpha-particle emission rates in the energy range 2.5-5.09 MeV was better than or equal to 0.02% for the defined solid-angle methods. When comparing total alpha-particle emission rates over the larger energy range 0-9 MeV (which includes all emissions from the daughter nuclides and the impurities), the agreement of the defined solid-angle methods was better than or equal to 0.05%. The 2 pi propo...

  15. The local skin dose conversion coefficients of electrons, protons and alpha particles calculated using the Geant4 code.

    Science.gov (United States)

    Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian

    2013-10-01

    The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code.

  16. First evidence of collective alpha particle effect on TAE modes in the TFTR D-T experiment

    International Nuclear Information System (INIS)

    Wong, K.L.; Schmidt, G.; Batha, S.H.

    1995-08-01

    The alpha particle effect on the excitation of toroidal Alfven eigenmodes (TAE) was investigated in deuterium-tritium (d-t) plasmas in the Tokamak Fusion Test Reactor (TFTR). RF power was used to position the plasma near the instability threshold, and the alpha particle effect was inferred from the reduction of RF power threshold for TAE instability in d-t plasmas. Initial calculations indicate that the alpha particles contribute 10--30% of the total drive in a d-t plasma with 3 MW of peak fusion power

  17. The influence of the calibration standard and the chemical composition of the water samples residue in the counting efficiency of proportional detectors for gross alpha and beta counting. Application on the radiologic control of the IPEN-CNEN/SP

    International Nuclear Information System (INIS)

    Santos, Cecilia Martins

    2003-01-01

    In this work the efficiency calibration curves of thin-window and low background gas-flow proportional counters were determined for calibration standards with different energies and different absorber thicknesses. For the gross alpha counting we have used 241 Am and natural uranium standards and for the gross beta counting we have used 90 Sr/ 90 Y and 137 Cs standards in residue thicknesses ranging from 0 to approximately 18 mg/cm 2 . These sample thicknesses were increased with a previously determined salted solution prepared simulating the chemical composition of the underground water of IPEN The counting efficiency for alpha emitters ranged from 0,273 +- 0,038 for a weightless residue to only 0,015 +- 0,002 in a planchet containing 15 mg/cm 2 of residue for 241 Am standard. For natural uranium standard the efficiency ranged from 0,322 +- 0,030 for a weightless residue to 0,023 +- 0,003 in a planchet containing 14,5 mg/cm 2 of residue. The counting efficiency for beta emitters ranged from 0,430 +- 0,036 for a weightless residue to 0,247 +- 0,020 in a planchet containing 17 mg/cm 2 of residue for 137 Cs standard. For 90 Sr/ 90 Y standard the efficiency ranged from 0,489 +- 0,041 for a weightless residue to 0,323 +- 0,026 in a planchet containing 18 mg/cm 2 of residue. Results make evident the counting efficiency variation with the alpha or beta emitters energies and the thickness of the water samples residue. So, the calibration standard, the thickness and the chemical composition of the residue must always be considered in the gross alpha and beta radioactivity determination in water samples. (author)

  18. Scattering of alpha particles from /sup 12/C and the /sup 12/C(. cap alpha. ,. gamma. )/sup 16/O stellar reaction rate

    Energy Technology Data Exchange (ETDEWEB)

    Plaga, R.; Becker, H.W.; Redder, A.; Rolfs, C.; Trautvetter, H.P.; Langanke, K.

    1987-04-06

    The elastic scattering of alpha particles from /sup 12/C has been investigated for 35 angles in the range theta/sub lab/ = 22/sup 0/ to 163/sup 0/ and for 51 energies at E/sub ..cap alpha../ = 1.0 to 6.6 MeV. The extracted phase shifts for l=0 to 6 partial waves have been parametrized in terms of the multilevel R-matrix formalism. Information on the deduced parameters of states in /sup 16/O is reported. The data reveal reduced ..cap alpha..-particle widths for the 6.92 and 7.12 MeV subthreshold states consistent with recent work. The implications for the stellar reaction rate of /sup 12/C(..cap alpha..,..gamma..)/sup 16/O are discussed.

  19. Effect of particle size on hydroxyapatite crystal-induced tumor necrosis factor alpha secretion by macrophages.

    Science.gov (United States)

    Nadra, Imad; Boccaccini, Aldo R; Philippidis, Pandelis; Whelan, Linda C; McCarthy, Geraldine M; Haskard, Dorian O; Landis, R Clive

    2008-01-01

    Macrophages may promote a vicious cycle of inflammation and calcification in the vessel wall by ingesting neointimal calcific deposits (predominantly hydroxyapatite) and secreting tumor necrosis factor (TNF)alpha, itself a vascular calcifying agent. Here we have investigated whether particle size affects the proinflammatory potential of hydroxyapatite crystals in vitro and whether the nuclear factor (NF)-kappaB pathway plays a role in the macrophage TNFalpha response. The particle size and nano-topography of nine different crystal preparations was analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and gas sorbtion analysis. Macrophage TNFalpha secretion was inversely related to hydroxyapatite particle size (P=0.011, Spearman rank correlation test) and surface pore size (P=0.014). A necessary role for the NF-kappaB pathway was demonstrated by time-dependent I kappaB alpha degradation and sensitivity to inhibitors of I kappaB alpha degradation. To test whether smaller particles were intrinsically more bioactive, their mitogenic activity on fibroblast proliferation was examined. This showed close correlation between TNFalpha secretion and crystal-induced fibroblast proliferation (P=0.007). In conclusion, the ability of hydroxyapatite crystals to stimulate macrophage TNFalpha secretion depends on NF-kappaB activation and is inversely related to particle and pore size, with crystals of 1-2 microm diameter and pore size of 10-50 A the most bioactive. Microscopic calcific deposits in early stages of atherosclerosis may therefore pose a greater inflammatory risk to the plaque than macroscopically or radiologically visible deposits in more advanced lesions.

  20. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Cheng, S.H.; Yu, K.N.

    2017-01-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  1. Quality assurance of alpha-particle dosimetry using peeled-off Gafchromic EBT3® film

    Science.gov (United States)

    Ng, C. Y. P.; Chun, S. L.; Yu, K. N.

    2016-08-01

    A novel alpha-particle dosimetry technique using Gafchromic EBT3 film has recently been proposed for calibrating the activity of alpha-emitting radiopharmaceuticals. In the present paper, we outlined four measures which could further help assure the quality of the method. First, we suggested an alternative method in fabricating the peeled-off EBT3 film. Films with a chosen size were cut from the original films and all the edges were sealed with silicone. These were immersed into deionized water for 19 d and the polyester covers of the EBT3 films could then be easily peeled off. The active layers in these peeled-off EBT3 films remained intact, and these films could be prepared reproducibly with ease. Second, we proposed a check on the integrity of the peeled-off film by comparing the responses of the pristine and peeled-off EBT3 films to the same X-ray irradiation. Third, we highlighted the importance of scanning directions of the films. The ;landscape; and ;portrait; scanning directions were defined as the scanning directions perpendicular and parallel to the long edge of the original EBT3 films, respectively. Our results showed that the responses were different for different scanning directions. As such, the same scanning direction should be used every time. Finally, we cautioned the need to confirm the uniformity of the alpha-particle source used for calibration. Radiochromic films are well known for their capability of providing two-dimensional dosimetric information. As such, EBT3 films could also be conveniently used to check the uniformity of the alpha-particle source.

  2. Stability of the Global Alfven Eigenmode in the presence of fusion alpha particles in an ignited tokamak plasma

    International Nuclear Information System (INIS)

    Fu, G.Y.; Van Dam, J.W.

    1989-05-01

    The stability of the Global Alfven Eigenmodes is investigated in the presence of super-Alfvenic energetic particles, such as the fusion-product alpha particles in an ignited deuterium-tritium tokamak plasma. Alpha particles tend to destabilize these modes when ω *α > ω A , where ω A is the shear-Alfven modal frequency and ω *α is the alpha particle diamagnetic drift frequency. This destabilization due to alpha particles is found to be significantly enhanced when the alpha particles are modeled with a slowing-down distribution function rather than with a Maxwellian. However, previously neglected electron damping due to the magnetic curvature drift is found to be comparable in magnitude to the destabilizing alpha particle term. Furthermore, the effects of toroidicity are also found to be stabilizing, since the intrinsic toroidicity induces poloidal mode coupling, which enhances the parallel electron damping from the sideband shear-Alfven Landau resonance. In particular, for the parameters of the proposed Compact Ignition Tokamak, the Global Alfven Eigenmodes are found to be completely stabilized by either the electron damping that enters through the magnetic curvature drift or the damping introduced by finite toroidicity. 29 refs., 8 figs., 1 tab

  3. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    Energy Technology Data Exchange (ETDEWEB)

    Sardini, Paul; Angileri, Axel [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Descostes, Michael [AREVA Mines, R& D Department, Paris (France); Duval, Samuel; Oger, Tugdual [AI4R SAS, Nantes (France); Patrier, Patricia [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Rividi, Nicolas [Service Camparis, Université Pierre et Marie Curie, Paris (France); Siitari-Kauppi, Marja [Radiochemistry Laboratory, University of Helsinki, Helsinki (Finland); Toubon, Hervé [AREVA Mines, R& D Department, Paris (France); Donnard, Jérôme [AI4R SAS, Nantes (France)

    2016-10-11

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as {sup 226}Ra, are complicated to localize in geo-materials. Because of its high specific activity, {sup 226}Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  4. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    International Nuclear Information System (INIS)

    Sardini, Paul; Angileri, Axel; Descostes, Michael; Duval, Samuel; Oger, Tugdual; Patrier, Patricia; Rividi, Nicolas; Siitari-Kauppi, Marja; Toubon, Hervé; Donnard, Jérôme

    2016-01-01

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as 226 Ra, are complicated to localize in geo-materials. Because of its high specific activity, 226 Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  5. Quantum 1/f noise in non-degerate semiconductors and emission statistics of alpha particles

    International Nuclear Information System (INIS)

    Kousik, G.S.

    1985-01-01

    Charged particle scattering is accompanied by the emission of soft photons. Handel's theory of 1/f noise, based on the infrared divergent coupling of the system to the electromagnetic field or other elementary excitations, states that the current associated with a beam of scattered particles will exhibit 1/f noise. The fraction of the particles scattered with an energy loss epsilon to soft photon emission is proportional to 1/epsilon and herein lies the origin of the quantum theory of 1/f noise. The 1/f noise caused by mobility fluctuations in semiconductors is related to the scattering cross section fluctuation given by Handel's theory, through the relaxation time. Chapters Two through Five of this dissertation presents the results of the detailed calculation of mobility fluctuation 1/f noise and Hooge parameter in nondegenerate semiconductors. Numerical results are given for silicon and gallium arsenide. Data obtained from extensive measurements on counting techniques for alpha-particles radioactive decay from a source containing 94 Pu 239 , 95 Am 241 and 96 Cm 244 are presented in Chapters Six and Seven of this dissertation. These data show that the statistics are non-Poissonian for large counting times (of the order of 1000 minutes) contrary to the popular belief that alpha-decay is an example of Poissonian statistics. Measurements of the Allan variance indicated the presence of a slow Lorentzian flicker noise and 1/f noise and the magnitude of the noise for large counting times is considerably larger than that predicted by Poissonian statistics

  6. New developments in JET neutron, alpha particle and fuel mixture diagnostics with potential relevance to ITER

    International Nuclear Information System (INIS)

    Murari, A.; Bertalot, L.; Angelone, M.; Pillon, M.; Ericsson, G.; Conroy, S.; Kaellne, J.; Kiptily, V.; Popovichev, S.; Adams, J.M.; Stork, D.; Afanasyiev, V.; Mironov, M.; Bonheure, G.

    2005-01-01

    Some recent JET campaigns, with the introduction of trace amount (n T /n D 4 He, provided unique opportunities to test new diagnostic approaches and technologies for the detection of neutrons, alpha particles and fuel mixture. With regard to neutron detection, the recent activity covered all the most essential aspects: calibration and cross validation of the diagnostics, measurement of the spatial distribution of the neutrons, particle transport and finally neutron spectrometry. The first tests of some new neutron detection technologies were also undertaken successfully during the TTE campaign. To improve JET diagnostic capability in the field of alpha particles, a strong development program was devoted to the measurement of their slowing down and imaging with gamma ray spectroscopy. A new approach for the fusion community to measure the fast ion losses, based on the activation technique, was also successfully attempted for the first time on JET. A careful assessment of the NPA potential to determine the fuel mixture and the particle transport coefficients is under way. (author)

  7. CHARGE-EXCHANGE LIMITS ON LOW-ENERGY {alpha}-PARTICLE FLUXES IN SOLAR FLARES

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, H. S. [SSL, UC Berkeley, CA 94720 (United States); Fletcher, L.; MacKinnon, A. L. [School of Physics and Astronomy, SUPA, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Woods, T. N., E-mail: hhudson@ssl.berkeley.edu [Laboratory for Atmospheric and Space Physics, University of Colorado, 1234 Innovation Dr., Boulder, CO 80303 (United States)

    2012-06-20

    This paper reports on a search for flare emission via charge-exchange radiation in the wings of the Ly{alpha} line of He II at 304 A, as originally suggested for hydrogen by Orrall and Zirker. Via this mechanism a primary {alpha} particle that penetrates into the neutral chromosphere can pick up an atomic electron and emit in the He II bound-bound spectrum before it stops. The Extreme-ultraviolet Variability Experiment on board the Solar Dynamics Observatory gives us our first chance to search for this effect systematically. The Orrall-Zirker mechanism has great importance for flare physics because of the essential roles that particle acceleration plays; this mechanism is one of the few proposed that would allow remote sensing of primary accelerated particles below a few MeV nucleon{sup -1}. We study 10 events in total, including the {gamma}-ray events SOL2010-06-12 (M2.0) and SOL2011-02-24 (M3.5) (the latter a limb flare), seven X-class flares, and one prominent M-class event that produced solar energetic particles. The absence of charge-exchange line wings may point to a need for more complete theoretical work. Some of the events do have broadband signatures, which could correspond to continua from other origins, but these do not have the spectral signatures expected from the Orrall-Zirker mechanism.

  8. Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Unlu, Kenan [Univ. of Texas, Austin, TX (United States); Rios-Martinez, Carlos [Univ. of Texas, Austin, TX (United States); Saglam, Mehmet [Univ. of Texas, Austin, TX (United States); Hart, Ron R. [Texas A & M Univ., College Station, TX (United States); Shipp, John D. [Texas A & M Univ., College Station, TX (United States); Rennie, John [Texas A & M Univ., College Station, TX (United States)

    1998-04-16

    Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

  9. A systematics of optical model compound nucleus formation cross sections for neutrons, proton, deuteron, 3He and alpha particle incidents

    International Nuclear Information System (INIS)

    Murata, Toru

    2000-01-01

    Simple formulae to reproduce the optical model compound nucleus formation cross sections for neutron, proton, deuteron, triton, 3 He and alpha particles are presented for target nuclei of light to medium weight mass region. (author)

  10. The new Athena alpha particle X-ray spectrometer for the Mars Exploration Rovers

    Science.gov (United States)

    Rieder, R.; Gellert, R.; Brückner, J.; Klingelhöfer, G.; Dreibus, G.; Yen, A.; Squyres, S. W.

    2003-11-01

    The new alpha particle X-ray spectrometer (APXS) is part of the Athena payload of the two Mars Exploration Rovers (MER). The APXS sensor head is attached to the turret of the instrument deployment device (IDD) of the rover. The APXS is a very light-weight instrument for determining the major and minor elemental composition of Martian soils, rocks, and other geological materials at the MER landing sites. The sensor head has simply to be docked by the IDD on the surface of the selected sample. X-ray radiation, excited by alpha particles and X rays of the radioactive sources, is recorded by a high-resolution X-ray detector. The X-ray spectra show elements starting from sodium up to yttrium, depending on their concentrations. The backscattered alpha spectra, measured by a ring of detectors, provide additional data on carbon and oxygen. By means of a proper calibration, the elemental concentrations are derived. Together with data from the two other Athena instruments mounted on the IDD, the samples under investigation can be fully characterized. Key APXS objectives are the determination of the chemistry of crustal rocks and soils and the examination of water-related deposits, sediments, or evaporates. Using the rock abrasion tool attached to the IDD, issues of weathering can be addressed by measuring natural and abraded surfaces of rocks.

  11. Selective alpha-particle mediated depletion of tumor vasculature with vascular normalization.

    Directory of Open Access Journals (Sweden)

    Jaspreet Singh Jaggi

    2007-03-01

    Full Text Available Abnormal regulation of angiogenesis in tumors results in the formation of vessels that are necessary for tumor growth, but compromised in structure and function. Abnormal tumor vasculature impairs oxygen and drug delivery and results in radiotherapy and chemotherapy resistance, respectively. Alpha particles are extraordinarily potent, short-ranged radiations with geometry uniquely suitable for selectively killing neovasculature.Actinium-225 ((225Ac-E4G10, an alpha-emitting antibody construct reactive with the unengaged form of vascular endothelial cadherin, is capable of potent, selective killing of tumor neovascular endothelium and late endothelial progenitors in bone-marrow and blood. No specific normal-tissue uptake of E4G10 was seen by imaging or post-mortem biodistribution studies in mice. In a mouse-model of prostatic carcinoma, (225Ac-E4G10 treatment resulted in inhibition of tumor growth, lower serum prostate specific antigen level and markedly prolonged survival, which was further enhanced by subsequent administration of paclitaxel. Immunohistochemistry revealed lower vessel density and enhanced tumor cell apoptosis in (225Ac-E4G10 treated tumors. Additionally, the residual tumor vasculature appeared normalized as evident by enhanced pericyte coverage following (225Ac-E4G10 therapy. However, no toxicity was observed in vascularized normal organs following (225Ac-E4G10 therapy.The data suggest that alpha-particle immunotherapy to neovasculature, alone or in combination with sequential chemotherapy, is an effective approach to cancer therapy.

  12. A study of the scintillation induced by alpha particles and gamma rays in liquid xenon in an electric field

    International Nuclear Information System (INIS)

    Dawson, J.V.; Howard, A.S.; Akimov, D.; Araujo, H.; Bewick, A.; Davidge, D.C.R.; Jones, W.G.; Joshi, M.; Lebedenko, V.N.; Liubarsky, I.; Quenby, J.J.; Rochester, G.; Shaul, D.; Sumner, T.J.; Walker, R.J.

    2005-01-01

    Scintillation produced in liquid xenon by alpha particles and gamma rays has been studied as a function of applied electric field. For back scattered gamma rays with energy of about 200keV, the number of scintillation photons was found to decrease by 64±2% with increasing field strength. Consequently, the pulse shape discrimination power between alpha particles and gamma rays is found to reduce with increasing field, but remaining non-zero at higher fields

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

    International Nuclear Information System (INIS)

    Roeske, John C; Stinchcomb, Thomas G

    2006-01-01

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

  14. Detection of {alpha} particles with the aid of a fluorescence counter; Detection des particules {alpha} a l'aide d'un compteur a fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Koechlin, Y

    1951-07-01

    The operation principle of the fluorescence counter, used as {alpha} particles detector, is analyzed in the first part. Detection can be done in two ways: by counting the pulses due to each {alpha} particle, or by integrating all pulses and measuring the average current obtained. In the second part, three series of measurements are presented: 1 - two fluorescent substances (zinc sulfate and anthracene) are placed in front of the photocathode of three types of photomultipliers (RCA 931A, EMI 4588, and EMI 5311). These substances are bombarded with the {alpha} radiations of a Po source and then irradiated by the {beta} and {gamma} radiations of a Ra source in order to study the light emission of these thin film substances when submitted to the three types of radiations. The results show that thanks to the amplitude of the emitted light pulses, the fluorescence counter, when submitted to the three types of radiations, allows to distinguish between the {alpha} radiations of the polonium and the {beta} and {gamma} radiations of the radium source. The output current of a 931A, when measured with a galvanometer, allows to detect Po sources with an intensity of about 10{sup -6} curie. This is observed when its photocathode receives the light from a ZnS-Ag coating bombarded by the {alpha} particles of Po. The quantum efficiency of the counter is close to 100% for the {alpha} particles of Po. This efficiency is evaluated by comparison with the efficiency of a thin wall Geiger-Mueller counter. Moreover, when a thin crystal of anthracene is used as detector, the energy of the incident particles can be measured with a 2% preciseness. (J.S.)

  15. A cluster expansion for bound three-alpha particles as a three-body problem

    International Nuclear Information System (INIS)

    Osman, A.

    1981-08-01

    A three-body model is proposed to study the nuclear bound states. The nucleus is described as a bound state of three clusters. A cluster expansion is introduced for the three cluster bound state problem. The present integral equations are treated by simple approximate solutions, which lead to effective potentials by using the present cluster expansion. The 12 C nucleus is described as a three-alpha particle bound state. The binding energy of 12 C is calculated numerically using the present cluster expansion as bound three-alpha clusters. The present three-body cluster expansion calculations are very near to the exact three-body calculations using separable potentials. The present theoretical calculations are in good agreement with the experimental measurements. (author)

  16. Measurement of radon progeny concentrations in air by alpha-particle spectrometey

    International Nuclear Information System (INIS)

    Kerr, G.D.

    1975-07-01

    A technique is presented for measuring air concentrations of the short-lived progeny of radon-222 by the use of alpha spectrometry. In this technique, the concentration of RaA, RaB, and RaC are calculated from one integral count of the RaA and two integral counts of the RaC' alpha-particle activity collected on a filter with an air sampling device. The influence of air sampling and counting intervals of time on the accuracy of the calculated concentrations is discussed in the report. A computer program is presented for use with this technique. It is written in the BASIC language. The program will calculate the air concentrations of RaA, RaB, and RaC, and will estimate the accuracy in these calculated concentrations. (U.S.)

  17. Estimation of the {alpha} particles and neutron distribution generated during a fusion reaction; Evaluation de la distribution des particules {alpha} et des neutrons issus de la reaction de fusion

    Energy Technology Data Exchange (ETDEWEB)

    Dellacherie, S.

    1997-12-01

    The respective distributions (or density probabilities) of {alpha} particles and neutrons have been modeled using a Monte-Carlo method for the thermonuclear fusion reaction D + T {yields} {alpha} + n + 17.6 MeV. (N.T.).

  18. Disturbance from Am-241 Photons of the Cellular Dose by Am-241 Alpha Emissions: Am-241 as an alternative source of alpha particles to radon daughters

    International Nuclear Information System (INIS)

    Lee, Ki-Man; Kim, Eun-Hee

    2015-01-01

    The Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU) has built an Am-241 alpha particle irradiator for study of cellular responses to radiation from radon daughters. The radon daughters of concern that cause internal exposure from inhalation of radon-contaminated air are Po-218, Po-214 and Po-210. In their alpha decay schemes, the yields of photon emissions are negligible. Unfortunately, Am-241, the source of alpha irradiator in RadBio Lab, emits photons at every alpha decay while transforming to Np-237 of long half-life. Employing Am-241 as the source simulating radon daughters, therefore, requires that photon emissions from Am-241 be specified in term of dose contribution. In this study, Monte Carlo calculations have been made to characterize dose contributions of Am-241 photon emissions. This study confirms that disturbance from Am-241 photon emissions of the cellular dose by Am-241 alpha emissions is negligible. Dose contamination fraction from photon emissions was 8.02 .. 10 -6 at 25 mm SSD at maximum. Also, note that LET in tissue-equivalent medium varies within about 20% for alpha particles at energies over 5 MeV

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

    International Nuclear Information System (INIS)

    Bourgeois, M.

    2007-05-01

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

  20. Gross-Pitaevskii equation for Bose particles in a double-well potential: Two-mode models and beyond

    International Nuclear Information System (INIS)

    Ananikian, D.; Bergeman, T.

    2006-01-01

    In this work, our primary goal has been to explore the range of validity of two-mode models for Bose-Einstein condensates in double-well potentials. Our derivation, like others, uses symmetric and antisymmetric condensate basis functions for the Gross-Pitaevskii equation. In what we call an 'improved two-mode model' (I2M), the tunneling coupling energy explicitly includes a nonlinear interaction term, which has been given previously in the literature but not widely appreciated. We show that when the atom number (and hence the extent of the wave function) in each well vary appreciably with time, the nonlinear interaction term produces a temporal change in the tunneling energy or rate, which has not previously been considered to our knowledge. In addition, we obtain a parameter, labeled ''interaction tunneling,'' that produces a decrease of the tunneling energy when the wave functions in the two wells overlap to some extent. Especially for larger values of the nonlinear interaction term, results from this model produce better agreement with numerical solutions of the time-dependent Gross-Pitaevskii equation in one and three dimensions, as compared with models that have no interaction term in the tunneling energy. The usefulness of this model is demonstrated by good agreement with recent experimental results for the tunneling oscillation frequency [Albiez et al., Phys. Rev. Lett. 95, 010402 (2005)]. We also present equations and results for a multimode approach, and use the I2M model to obtain modified equations for the second-quantized version of the Bose-Einstein double-well problem

  1. Crosschecking of alpha particle monitor reactions up to 50 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Ditrói, F.; Szűcs, Z. [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Haba, H.; Komori, Y. [Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan); Saito, M. [Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan)

    2017-04-15

    Selected reactions with well-defined excitation functions can be used to monitor the parameters of charged particle beams. The frequently used reactions for monitoring alpha particle beams are the {sup 27}Al(α,x){sup 22,24}Na, {sup nat}Ti(α,x){sup 51}Cr, {sup nat}Cu(α,x){sup 66,67}Ga and {sup nat}Cu(α,x){sup 65}Zn reactions. The excitation functions for these reactions were studied using the activation method and stacked target irradiation technique to crosscheck and to compare the above six reactions. Thin metallic foils with natural isotopic composition and well defined thickness were stacked together in sandwich targets and were irradiated at the AVF cyclotron of RIKEN with an alpha particle beam of 51.2 MeV. The activity of the target foils were assessed by using high-resolution gamma spectrometers of high purity Ge detectors. The data sets of the six processes were crosschecked with each other to provide consistent, cross-linked numerical cross section data.

  2. Radiobiological Effects of Alpha-Particles from Astatine-211: From DNA Damage to Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, Kristina

    2011-05-15

    In recent years, the use of high linear energy transfer (LET) radiation for radiotherapeutic applications has gained increased interest. Astatine-211 (211At) is an alpha-particle emitting radionuclide, promising for targeted radioimmunotherapy of isolated tumor cells and microscopic clusters. To improve development of safe radiotherapy using 211At it is important to increase our knowledge of the radiobiological effects in cells. During radiotherapy, both tumors and adjacent normal tissue will be irradiated and therefore, it is of importance to understand differences in the radio response between proliferating and resting cells. The aim of this thesis was to investigate effects in fibroblasts with different proliferation status after irradiation with alpha-particles from 211At or X-rays, from inflicted DNA damage, to cellular responses and biological consequences. Throughout this work, irradiation was performed with alpha-particles from 211A or X-rays. The induction and repair of double-strand breaks (DSBs) in human normal fibroblasts were investigated using pulsed-field gel electrophoresis and fragment analysis. The relative biological effectiveness (RBE) of 211At for DSB induction varied between 1.4 and 3.1. A small increase of DSBs was observed in cycling cells compared to stationary cells. The repair kinetics was slower after 211At and more residual damage was found after 24 h. Comparison between cells with different proliferation status showed that the repair was inefficient in cycling cells with more residual damage, regardless of radiation quality. Activation of cell cycle arrests was investigated using immunofluorescent labeling of the checkpoint kinase Chk2 and by measuring cell cycle distributions with flow cytometry analysis. After alpha-particle irradiation, the average number of Chk2-foci was larger and the cells had a more affected cell cycle progression for several weeks compared with X-irradiated cells, indicating a more powerful arrest after 211At

  3. Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J. [Medical Physics Research Group, Physics Department, Education College, Salahaddin University-Erbil, Iraqi Kurdistan (Iraq)

    2015-07-01

    An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and the impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ({sup 226}Ra, and {sup 137}Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm{sup 2}) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)

  4. Evaluate an impact of incident alpha particle and gamma ray on human blood components: A comparison study

    International Nuclear Information System (INIS)

    Ismail, Asaad H.; Yaba, Sardar P.; Ismail, Haider J.

    2015-01-01

    An impact of alpha and gamma irradiation on human blood components have been evaluated and compared for healthy blood samples (male and females). Irradiation dose and time of irradiation calibrated and considered as a main comparison factors. Density of blood components measured for each in vitro irradiation before and after irradiation for males and females. Survey radiation dosimeter (Inspector Exp) and nuclear track detectors type CR-39 used to evaluate exposure dose rate and incident density of alpha particles, respectively. Experiment results verified that the irradiation of blood makes ionizing of blood components, either alpha or gamma irradiation dose, and the impacts of ionizing radiation were relativity for WBC, RBC, and PLT. Limited irradiation doses of 1-5 μSv/hr considered as a low radiation dose of alpha and gamma radiation sources ( 226 Ra, and 137 Cs). Density of alpha particles accumulated on the blood surface was 34 (alpha particle/cm 2 ) for selected dose of incident alpha particle. Optimum value of irradiation dose and time of irradiation were 5 μSv/hr and 4 second for males and females. On the other hands, the values of irradiation dose and time of irradiation were 2.1 μSv/hr and 2 second for males and females for gamma irradiation. Thus, present results demonstrated that densities of RBC and WBC cells are capable of inducing reproduction in vitro for both type of irradiation. (authors)

  5. Physical consequences of the alpha/beta rule which accurately calculates particle masses

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, Karl Otto [Fritz Lipmann Institute, Beutenbergstr.11, D07745 Jena (Germany)

    2015-07-01

    Using the fine structure constant α (=1/137.036), the proton vs. electron mass ratio β (= 1836.2) and the integers m and n, the α/β rule: m{sub particle} = α{sup -n} x β m x 27.2 eV/c{sup 2} allows almost exact calculation of particle masses. (K.O.Greulich, DPG Spring meeting 2014, Mainz, T99.4) With n=2, m=0 the electron mass becomes 510.79 keV/c{sup 2} (experimental 511 keV/c{sup 2}) With n=2, m=1 the proton mass is 937.9 MeV/c{sup 2} (literature 938.3 MeV/c{sup 2}). For n=3 and m=1 a particle with 128.6 GeV/c{sup 2} close to the reported Higgs mass, is expected. For n=14 and m=-1 the Planck mass results. The calculated masses for gauge bosons and for quarks have similar accuracy. All masses fit into the same scheme (the alpha/beta rule), indicating that non of these particle masses play an extraordinary role. Particularly, the Higgs Boson, often termed the *God particle* plays in this sense no extraordinary role. In addition, particle masses are intimately correlated with the fine structure constant α. If particle masses have been constant over all times, α must have been constant over these times. In addition, the ionization energy of the hydrogen atom (13.6 eV) needs to have been constant if particle masses have been unchanged or vice versa. In conclusion, the α/β rule needs to be taken into account when cosmological models are developed.

  6. Matrix Characterization of Plutonium Residues by Alpha-Particle Self-Interrogation

    International Nuclear Information System (INIS)

    Prettyman, T.H.; Foster, L.A.; Staples, P.

    1998-01-01

    Legacy plutonium residues often have inadequate item descriptions. Nondestructive characterization can help segregate these items for reprocessing or provide information needed for disposal or storage. Alpha particle-induced gamma-ray spectra contain a wealth of information that can be used for matrix characterization. We demonstrate how this information can be used for item identification. Gamma-ray spectra were recorded at the Los Alamos Plutonium Facility from a variety of legacy, plutonium-processing residues and product materials. The comparison and analysis of these spectra are presented

  7. The instrumental blank of the Mars Science Laboratory alpha particle X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada)

    2012-10-01

    The alpha particle X-ray spectrometers on the Mars exploration rovers Spirit and Opportunity accomplished extensive elemental analysis of the Martian surface through a combination of XRF and PIXE. An advanced APXS is now part of the Mars Science Laboratory's Curiosity rover. APXS spectra contain contributions which enhance elemental peak areas but which do not arise from these elements within the sample under study, thereby introducing error into derived concentrations. A detailed examination of these effects in the MSL APXS enables us to test two schemes for making the necessary corrections.

  8. Doping of semiconductors using radiation defects produced by irradiation with protons and alpha particles

    International Nuclear Information System (INIS)

    Kozlov, V.A.; Kozlovski, V.V.

    2001-01-01

    One of the modern methods for modifying semiconductors using beams of protons and alpha particles is analyzed; this modification is accomplished by the controlled introduction of radiation defects into the semiconductor. It is shown that doping semiconductors with radiation defects produced by irradiation with light ions opens up fresh opportunities for controlling the properties of semiconducting materials and for the development of new devices designed for optoelectronics, microelectronics, and nanoelectronics based on these materials; these devices differ favorably from those obtained by conventional doping methods, i.e., by diffusion, epitaxy, and ion implantation

  9. Alpha particle emission as a probe of the level density in highly excited A∼200 nuclei

    International Nuclear Information System (INIS)

    Fabris, D.; Fioretto, E.; Viesti, G.; Cinausero, M.; Gelli, N.; Hagel, K.; Lucarelli, F.; Natowitz, J.B.; Nebbia, G.; Prete, G.; Wada, R.

    1994-01-01

    The alpha particle emission from 90 to 140 MeV 19 F+ 181 Ta fusion-evaporation reactions has been studied. The comparisons of the experimental spectral shapes and multiplicities with statistical model predictions indicate a need to use an excitation energy dependent level-density parameter a=A/K in which K increases with excitation energy. This increase is more rapid than that in lower mass nuclei. The effect of this change in level density on the prescission multiplicities in fission is significant

  10. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

    2007-11-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

  11. Laser and alpha particle characterization of floating-base BJT detector

    Energy Technology Data Exchange (ETDEWEB)

    Tyzhnevyi, V., E-mail: tyzhnevyi@disi.unitn.i [Universita di Trento and INFN Trento, Trento (Italy); Batignani, G. [Dipartimento di Fisica, Universita di Pisa and INFN Pisa, Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Universita di Trieste and INFN Trieste, Trieste (Italy); Dalla Betta, G.-F. [Universita di Trento and INFN Trento, Trento (Italy); Verzellesi, G. [Universita di Modena e Reggio Emilia and INFN Trento, Reggio Emilia (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), Trento (Italy)

    2010-05-21

    In this work, we investigate the detection properties of existing prototypes of BJT detectors operated with floating base. We report about results of two functional tests. The charge-collection properties of BJT detectors were evaluated by means of a pulsed laser setup. The response to {alpha}-particles emitted from radioactive {sup 241}Am source are also presented. Experimental results show that current gains of about 450 with response times in the order of 50 {mu}s are preserved even in this non-standard operation mode, in spite of a non-optimized structure.

  12. Pre-equilibrium decay process in alpha particle induced reactions on thulium and tantalum

    International Nuclear Information System (INIS)

    Mohan, Rao, A.V.; Chintalapudi, S.N.

    1994-01-01

    Alpha particle induced reactions on the target elements Thulium and Tantalum were investigated upto 60 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for six reactions of 169 Tm(α,xn); x=1-4 and 181 Ta(α,xn); x=2,4 were studied. The experimental results were compared with the updated version of Hybrid model (ALICE/90) using initial exciton configuration n 0 =4(4pOh). A general agreement was found for all the reactions with this option. (author)

  13. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

  14. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-01-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size

  15. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-01-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands during the period when this form of therapy was given for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The dose rate was approximately 100 rads/min for all cases. Fractionation varied but it is known for all cases

  16. Creep tests of AISI 316 stainless steel irradiated by alpha particles of 28 MeV

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.

    1986-01-01

    He-embrittlement effect in AISI 316 SS type throught creep tests performed with annealed and cold worked thin specimens is analized. Measurements were carried out at 700 and 750 0 C, stress of 100 MPa in vacuum better than 10 -5 torr. The He-implantations were made with the cyclotron CV-28 IPEN-CNEN/SP. Using an alpha-particle beam of 28 MeV, with concentration of 26 appm. From the valves of rupture deformation, epsilon sub(R), and rupture time, t sub(R), it was verified that he had a great effect on the operational life and ductility of this material. (Author) [pt

  17. Model of alpha particle diffusion in the outer limiter shadow of TFTR

    International Nuclear Information System (INIS)

    Wang, S.; Academia Sinica, Hefei, Anhui; Zweben, S.J.

    1996-05-01

    A new code, Monte Carlo Collisional Stochastic Orbit Retracing (MCCSOR), has been developed to model the alpha particle loss signal as measured by the outer midplane scintillator detector in TFTR. The shadowing effects due to the outer limiters and the detector itself have been included, along with a pitch angle scattering and stochastic ripple diffusion. Shadowing by the outer limiters has a strong effect on both the magnitude and pitch angle distribution of the calculated loss. There is at least qualitative agreement between the calculated results and the experimental data

  18. Current-drive by lower hybrid waves in the presence of energetic alpha-particles

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N.J.; Rax, J.M.

    1991-10-01

    Many experiments have now proved the effectiveness of lower hybrid waves for driving toroidal current in tokamaks. The use of these waves, however, to provide all the current in a reactor is thought to be uncertain because the waves may not penetrate the center of the more energetic reactor plasma, and, if they did, the wave power may be absorbed by alpha particles rather than by electrons. This paper explores the conditions under which lower-hybrid waves might actually drive all the current. 26 refs.

  19. Alpha-particle emission probabilities in the decay of 239Pu

    International Nuclear Information System (INIS)

    Garcia-Torano, E.; Acena, M.L.; Bortels, G.; Mouchel, D.

    1993-01-01

    The alpha-particle emission probabilities (P α ) of 239 Pu have been measured using material of highest enrichment and radiochemical purity, thin sources produced by vacuum sublimation, and high-resolution α spectroscopy with ion-implanted Si detectors (PIPS). The results for the major emissions are P α0.07 =0.7077±0.0014, P α13 =0.1711±0.0014 and P α51 =0.1194±0.0007, which for the P α0.07 is about 3.6% lower than the recent evaluated value in the literature. (orig.)

  20. Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

    Science.gov (United States)

    Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

    2016-01-01

    The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter

  1. Detection alpha particles and Cf-252 fission fragments with track solid detectors and with surface barrier detectors: efficiency determination

    International Nuclear Information System (INIS)

    Khouri, M.T.F.C.; Koskinas, M.F.; Andrade, C. de; Vilela, E.C.; Hinostroza, H.; Kaschiny, J.R.A.; Costa, M.S. da; Rizzo, P.; Santos, W.M.S.

    1990-01-01

    The technique of particle detection by solid track detectors, types of developing and analysis of results are presented. Efficiency measurements of alpha particle detection with Makrofol e and surface barrier detector are made. Detection of Cf-252 fission fragments is shown. (L.C.)

  2. Detection of alpha particles and Cf-252 fission fragments with solid track detectors and surface barrier detector. Efficiency calculation

    International Nuclear Information System (INIS)

    Khouri, M.T.F.C.; Koskinas, M.F.; Andrade, C. de; Vilela, E.C.; Hinostroza, H.; Kaschiny, J.E.A.; Costa, M.S. da; Rizzo, P.; Santos, W.M.S.

    1990-01-01

    A technique for particle detection by using track solid detector and also types of revealing and result analysis are presented concerned to Cf-252 fission fragments detection. Measurements of alpha particles detection efficiency using Makrofol E and surface barrier detector are performed. (L.C.J.A.)

  3. Studies of isothermal annealing of fission fragment and alpha particle tracks in Cr-39 polymer detectors

    International Nuclear Information System (INIS)

    Zaky, M.F.; Youssef, A.A.

    2002-01-01

    Two groups of CR-39 detectors samples are exposed to two types of charged particle radiation. The first group are severe damaged with fission fragment tracks from 2 52C f source. The second accepted alpha particles resulting from the interaction of highly energetic 1 9F -ions and a copper disk with thickness 1 cm, which are of less damage tracks than fission fragments. , The isothermal annealing of tracks in the temperature range from 175 to 300 degree C in step 25 degree C for annealing time of 10,15,20,25 and 30 minutes has been investigated. The changes introduced in the track density and track diameter for two types of irradiation in the detector have been observed and compared between them. The results indicate that the track density and the size of the tracks are considerably changed due to annealing

  4. Neoclassical alpha-particle losses in tokamaks allowing for large orbit widths

    International Nuclear Information System (INIS)

    Cox, M.; O'Brien, M.R.; Zaitsev, F.S.

    1994-01-01

    Alpha-particle physics is of particular importance now that research into controlled fusion has reached thermonuclear parameters and D-T fuel has been used in JET and TFTR. Here we address the important topic of α-particle transport: if transport is too low helium ash accumulates quenching the burn; if it is too high heating of the plasma by fast α-particles is insufficient to maintain the burn. We give results from simulations of α-particle distributions (f α ) which self-consistently treat α-particle birth, collisional slowing down and neoclassical radial transport. The (steady-state) f α is calculated by the FPP code as a function of speed (v), pitch-angle (θ) and flux surface radius (r). This code is based on a 3D Fokker-Planck theory of 'banana regime' neoclassical effects in tokamaks which can treat large deviations of fast ion orbits from flux surfaces and non-Maxwellian distributions. The code reproduces standard neoclassical results for Maxwellian distributions in the large aspect ratio (ε) and small orbit width (Δ) limits (e.g. radial fluxes, conductivities and bootstrap currents), but can also be used for small ε and large Δ which are difficult to treat analytically. The code is particularly useful for α-particle studies as (a) the experimental evidence is that fast ion transport is usually consistent with neoclassical theory, unlike electron or thermal ion transport, and (b) trapped fast ion orbits can deviate greatly from flux surfaces. An alternative to this Fokker-Planck treatment is Monte Carlo modelling. However, representation of the detailed structure of f α (θ,v,r) would require very large number of particles, and hence be very slow. Calculations have been made for parameters typical of TFTR, JET, SSTR (an 'advanced tokamak' reactor) and STR (a tight aspect ratio or 'spherical' tokamak reactor, though only the JET results are discussed in detail. (author) 4 refs., 4 figs

  5. Project and construction of a spectrometer for alpha particles using surface barrier detectors

    International Nuclear Information System (INIS)

    Terini, R.A.

    1986-01-01

    The project, construction, tests and some applications of a system for alpha and beta spectrometry, using surface barrier detector are described. The device includes a solid state detector ORTEC-Series F coupled to a system for amplifying the charges produced by passage of an ionizing particle through the detector. The amplifying system is composed by a charge sensitive pre-amplifier, which employs an operational amplifier CA 3140, and a low noise linear amplifier, which is based on the operational amplifiers CA 3140 and LM 301. The pre-amplifier stage input impedance is on the order of TΩ and produces output pulses which heights are proportional to total charge produced by passage of particle through the detector sensitive volume. The main advantage to use charge sensitive system lies in obtention of independent pulse heights of the distributed capacity of connecting cable between the detector and the pre-amplifier. The total system amplification ca reach a maximum of 50.000 in the linear region. Pulses are analysed in a multichannel system ORTEC, model 6240. The amplifier system is easily constructed and low cost using components available in the national market, and it can be employed with ionization chambers, proportional counters, scitillation counters and semiconductor detectors. The results of spectrometer application for alpha spectrometry of AM 241 source were compared to systems made with imported stages. (Author) [pt

  6. Activation cross sections of longer-lived radionuclides produced in germanium by alpha particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Takács, M.P.; Ditrói, F. [Institute for Nuclear Research, Hungarian Academy of Sciences, Atomki, 4026 Debrecen (Hungary); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Haba, H.; Komori, Y. [Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)

    2016-09-15

    The cross sections of alpha particles induced nuclear reactions on natural germanium were investigated by using the standard stacked foil target technique, the activation method and high resolution gamma spectrometry. Targets with thickness of about 1 μm were prepared from natural Ge by vacuum evaporation onto 25 μm thick polyimide (Kapton) backing foils. Stacks were composed of Kapton-Ge-Ge-Kapton sandwich target foils and additional titanium monitor foils with nominal thickness of 11 μm to monitor the beam parameters using the {sup nat}Ti(α,x){sup 51}Cr reaction. The irradiations were done with E{sub α} = 20.7 and E{sub α} = 51.25 MeV, I{sub α} = 50 nA alpha particle beams for about 1 h. Direct or cumulative activation cross sections were determined for production of the {sup 72,73,75}Se, {sup 71,72,74,76,78}As, and {sup 69}Ge radionuclides. The obtained experimental cross sections were compared to the results of theoretical calculations taken from the TENDL data library based on the TALYS computer code. A comparison was made with available experimental data measured earlier. Thick target yields were deduced from the experimental cross sections and compared with the data published before.

  7. Molecular pathways in the bystander response of cells exposed to very low fluences of alpha particles

    International Nuclear Information System (INIS)

    Little, J.B.

    2000-01-01

    Full text: We have examined biological effects in cell populations exposed to very low mean doses of alpha radiation by which only a small fraction of the cells are actually traversed by an alpha particle. We showed earlier that an enhanced frequency of sister chromatid exchanges and HPRT mutations occur in the non-irradiated, 'bystander' cells. The frequency of mutations induced by a single alpha particle traversing the nucleus of a cell was increased nearly fivefold at the lowest fluence studied, a result of mutations occurring in bystander cells. This was associated with a similar increase in the induction of micronuclei, indicating the induction of DNA damage in bystander cells. In order to gain information concerning molecular pathways, we studied changes in gene expression in bystander cells in confluent cultures of human diploid fibroblasts or mouse embryo-derived fibroblasts (MEFs) by western analysis and in-situ immunofluorescence. The expression levels of p53, p21 Waf1 and p34 cdc2 were significantly modulated in bystander cells. The upregulation of p53 and p21 Waf1 did not occur in cultures irradiated at low density, and was markedly reduced in the presence of the gap junction inhibitor lindane. The importance of gap-junction mediated intercellular communication was confirmed in connexin-43 knockout MEFs. Western blot analyses and electrophoretic mobility shift assays indicate that the bystander response is suppressed by incubation with superoxide dismutase as well as an inhibitor of NADPH oxidase, and is associated with the induction of NFKB, suggesting the effect is mediated by oxidative stress. The stress-activated protein kinase p38 and its downstream effector ATF2 are also induced in bystander cells independent of oxidative stress. These results will be discussed in terms of whether activation of the p53 damage response pathway is the direct result of signaling from irradiated cells, or rather is a consequence of DNA induced damage in the bystander

  8. A new method for alpha-particle detection in a classroom experiment

    International Nuclear Information System (INIS)

    Simon, A.; Pintye, Z.; Molnar, J.

    2005-01-01

    Complete text of publication follows. The World Year of Physics (WYP 2005) was a worldwide celebration of Physics and its importance in our everyday lives. In harmony with its aims, that is to raise the worldwide awareness of Physics and Physical Science, we introduced a novel lab work involving a new imaging and data evaluation method for alpha-particle detection, which can be easily implemented in a classroom environment. The target group of the experiments is mainly secondary school students (age between 16-18 years). Our aim is to motivate students to develop a better understanding of Physics, allowing them to experience for themselves something of its fascination. In order to increase their attractiveness, the experiments include using a CMOS video image sensor with a video output. The covering glass window of the sensor must be carefully removed in order to make it sensitive for alpha rays. The sensor is connected to a computer where the images are recorded as a short video clip. The recorded video is played back by frames. The resulted frames are then merged together into one image. On this image the student can count the number of spots, where each spot corresponds to a hit of an alpha particle. The experiment can also be visible on a TV screen even by a whole class, however the authors suggest implementing the following experiments as a practical work individually or in small groups. As students are familiar with modern information technology, we think that they will be highly motivated to make these experiments on their own. Acknowledgements. The development of the above experimental setup was funded by ATOMKI and it was presented to the interactive science centre 'Magic corner', Debrecen, Hungary at Christmas, 2005. (author)

  9. Investigation of the performance of alpha particle counting and alpha-gamma discrimination by pulse shape with micro-pixel avalanche photodiode

    International Nuclear Information System (INIS)

    Ahmadov, G.; Madatov, R.; Sadigov, A.; Sadygov, Z.; Jafarova, E.; Ahmadov, G.; Sadygov, Z.; Olshevski, A.; Zerrouk, F.; Mukhtarov, R.

    2015-01-01

    Being capable measuring small lights gives possibility to use micro-pixel avalanche photodiodes with scintillators. It is shown two prototypes to use micro-pixel avalanche photodiodes with and without scintillators as alpha and gamma counters in this paper. First prototype is to use two micro-pixel avalanche photodiodes. One for detecting alpha particles and closer to it, the second one with a thin plastic scintillator for detecting gamma rays. Second prototype is called two-layers configuration in which it is used only one micro-pixel avalanche photodiode, but two scntillators with different decay times. One can distinquish alpha particle and gamma ray events by using pulse shape discrimination techniques in the two-layer configuration. In this work an alpha particle and gamma ray counting performance of micro-pixel avalanche photodiodes without scintillators and its combination of plastic and BGO+ plastic scintillators was investigated. Obtained results showed the detection performance of the micro-pixel avalanche photodiodes in combination with plastic scintillator was about the same as conventional semiconductor detectors

  10. Differential Effects of Alpha-Particle Radiation and X-Irradiation on Genes Associated with Apoptosis

    International Nuclear Information System (INIS)

    Chauhan, V.; Howland, M.; Chen, J.; Kutzner, B.; Wilkins, R.C.

    2011-01-01

    This study examined differential effects of alpha-(α) particle radiation and X-rays on apoptosis and associated changes in gene expression. Human monocytic cells were exposed to a-particle radiation and X-rays from 0 to 1.5 Gy. Four days postexposure, cell death was measured by flow cytometry and 84 genes related to apoptosis were analyzed using real-time PCR. On average, 33% of the cells were apoptotic at 1.5 Gy of a-particle radiation. Transcript profiling showed statistical expression of 15 genes at all three doses tested. Cells exposed to X-rays were <5% apoptotic at ∼1.5 Gy and induced less than a 2-fold expression in 6 apoptotic genes at the higher doses of radiation. Among these 6 genes, Fas and TNF-α were common to the α-irradiated cells. This data suggests that α-particle radiation initiates cell death by TNF-a and Fas activation and through intermediate signalling mediators that are distinct from X-irradiated cells

  11. Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report

    International Nuclear Information System (INIS)

    LaVerne, J.A.

    1998-01-01

    'This project uses fundamental radiation chemical techniques to elucidate the basic processes occurring in the heavy-ion radiolysis of solid hydrocarbon matrices such as polymers and organic resins that are associated with many of the transuranic waste deposits or the transportation of these radionuclides. The environmental management of mixed waste containing transuranic radionuclides is difficult because these nuclides are alpha particle emitters and the energy deposited by the alpha particles causes chemical transformations in the matrices accompanying the waste. Most radiolysis programs focus on conventional radiation such as gamma rays, but the chemical changes induced by alpha particles and other heavy ions are typically very different and product yields can vary by more than an order of magnitude. The objective of this research is to measure the production of gases, especially molecular hydrogen, produced in the proton, helium ion, and carbon ion radiolysis of selected solid organic matrices in order to obtain fundamental mechanistic information on the radiolytic decomposition of these materials. This knowledge can also be used to directly give reasonable estimates of explosive or flammability hazards in the storage or transport of transuranic wastes in order to enhance the safety of DOE sites. This report summarizes the work after eight months of a three-year project on determining the production of hazardous gases in transuranic waste. The first stage of the project was to design and build an assembly to irradiate solid organic matrices using accelerated ion beams. It is necessary to measure absolute radiolytic yields, and simulate some of the conditions found in the field. A window assembly was constructed allowing the beam to pass consecutively through a collimator, a vacuum exit window and into the solid sample. The beam is stopped in the sample and the entire end of the assembly is a Faraday cup. Integration of the collected current, in conjunction

  12. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    International Nuclear Information System (INIS)

    Wong, T.P.W.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2009-01-01

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  13. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  14. Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52 MeV

    OpenAIRE

    Ditrói, F.; Takács, S.; Haba, H.; Komori, Y.; Aikawa, M.

    2016-01-01

    Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2 MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. Th...

  15. Spatial distribution patterns of energy deposition and cellular radiation effects in lung tissue following simulated exposure to alpha particles

    International Nuclear Information System (INIS)

    Hofmann, W.; Crawford-Brown, D.J.

    1990-01-01

    Randomly oriented sections of rat tissue have been digitised to provide the contours of tissue-air interfaces and the locations of individual cell nuclei in the alveolated region of the lung. Sources of alpha particles with varying irradiation geometries and densities are simulated to compute the resulting random pattern of cellular irradiation, i.e. spatial coordinates, frequency, track length, and energy of traversals by the emitted alpha particles. Probabilities per unit track lengths, derived from experimental data on in vitro cellular inactivation and transformation, are then applied to the results of the alpha exposure simulations to yield an estimate of the number of both dead and viable transformed cells and their spatial distributions. If lung cancer risk is linearly related to the number of transformed cells, the carcinogenic risk for hot particles is always smaller than that for a uniform nuclide distribution of the same activity. (author)

  16. Helium burning: a further measurement of the beta-delayed alpha-particle emission of 16 Na

    International Nuclear Information System (INIS)

    Gai, Moshe

    1997-01-01

    The 12 C (α,γ) 16 O is a key (but still unknown) reaction in helium burning. Several attempts to constrain the p-wave S-factor at Helium burning temperatures (200 M K) using the beta-delayed alpha-particle emission of 16 N have been made. However, some discrepancy exists between the spectra measured at Settle and that of TRIUMF. We have improved our previous study of the beta-delayed alpha-particle emission of 16 N by improving our statistical sample (by more than a factor of 5), improving the energy resolution of the experiment (by 20%), and in understanding our line shape, deduced from measured quantities. Our newly measured spectrum of the beta-delayed alpha-particle emission of 16 N is consistent with the Seattle ('95) data, as well as an earlier experiment performed at Mains ('71) and is not consistent with the TRIUMF ('94) data. (author)

  17. Alpha particle response for a prototype radiation survey meter based on poly(ethylene terephthalate) with un-doping fluorescent guest molecules

    International Nuclear Information System (INIS)

    Nguyen, Philip; Nakamura, Hidehito; Sato, Nobuhiro; Takahashi, Tomoyuki; Maki, Daisuke; Kanayama, Masaya; Takahashi, Sentaro; Kitamura, Hisashi; Shirakawa, Yoshiyuki

    2016-01-01

    There is no radiation survey meter that can discriminate among alpha particles, beta particles, and gamma-rays with one material. Previously, undoped poly(ethylene terephthalate) (PET) has been shown to be an effective material for beta particle and gamma-ray detection. Here, we demonstrate a prototype survey meter for alpha particles based on undoped PET. A 140 × 72 × 1-mm PET substrate was fabricated with mirrored surfaces. It was incorporated in a unique detection section of the survey meter that directly detects alpha particles. The prototype exhibited an unambiguous response to alpha particles from a 241 Am radioactive source. These results demonstrate that undoped PET can perform well in survey meters for alpha particle detection. Overall, the PET-based survey meter has the potential to detect multiple types of radiation, and will spawn an unprecedented type of radiation survey meter based on undoped aromatic ring polymers. (author)

  18. Preparation of a thin polysulfone phosphor sheet for the detection of alpha particles using adhesive process

    International Nuclear Information System (INIS)

    Seo, B. K.; Woo, Z. H.; Kim, G. H.; Chang, U. S.; Oh, W. Z.; Lee, K. W.; Han, M. J.

    2005-01-01

    According to atomic energy law and connection regs, the surface contamination of nuclear facilities should be monitored routinely. Surface contamination is divided into removable and fixed contamination. Fixed contamination is measured by a direct method with a survey meter. And removable contamination is measured by an indirect method using smear paper and a low background proportional counter. Also, in the decommissioning process of a nuclear research facilities, such as Korean Research Reactor 1 and 2 and Uranium Conversion Plant, a significant amount of nuclear wastes is produced. The wastes contaminated must be surveyed for the disposal and reuse in the future. In the previous study the medium, scintillatorembedded polymer membrane for detecting the alpharay, was prepared by impregnating organic scintillators in a membrane structure. The plastic scintillator consists of polysulfone(PSF) as a matrix with PPO as an organic scintillator and POPOP as a wave shifting agent dissolved in the matrix. But, an organic plastic scintillator was inadequate to detect the alpha particle in the alpha-beta mixing field because its light output is smaller than beta ray one. So, a thin phosphor sheet was prepared, which consisted of a very uniform deposit of silver activated zinc sulfide (ZnS(Ag)) phosphor applied to on side of clear polysulfone plastic sheet

  19. Survey of atomic data base needs and accuracies for helium beam stopping and alpha particle diagnostics for ITER

    International Nuclear Information System (INIS)

    Summers, H.P.; Hellermann, M. von.

    1992-01-01

    This report is concerned with establishing a recommended collection of atomic collision data for the modelling, experimental investigation and exploitation of helium beams. The motivation stems from proposals for diagnostic beams for the ITER tokamak, targeted at alpha particle measurement via double charge transfer, neutralized alpha particle analysis and spectroscopic analysis of recombination radiation. The report discusses the beam energies, species involved in collisions with the helium atom beam (fuel, helium ash and plasma impurities) and plasma conditions prevailing in large tokamak devices. It also lists the required cross-section data

  20. Determination of plutonium isotopes in bilberry using liquid scintillation spectrometry and alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Seferinoğlu, Meryem; Aslan, Nazife; Kurt, Aylin; Erden, Pınar Esra; Mert, Hülya

    2014-01-01

    This paper presents α-particle spectrometry and liquid scintillation spectrometry methods to determine plutonium isotopes in bilberry. The analytical procedure involves sample preparation steps for ashing, digestion of bilberry samples, radiochemical separation of plutonium radioisotopes and their measurement. The validity of the method was checked for coherence using the ζ test, z-test, relative bias and relative uncertainty outlier tests. The results indicated that the recommended procedures for both measurement systems could be successfully applied for the accurate determination of plutonium activities in bilberry samples. - Highlights: • Sample preparation methods for Pu using LSS and alpha spectrometry developed. • Complete separation of plutonium from interfering radionuclides. • Commercial bilberry was spiked with NPL 2011 (AH-B11144) proficiency test sample. • Results were checked using ζ test, z-test, rel. bias and rel. uncert. outlier tests. • Recommended procedures successfully applied to bilberry samples

  1. Specific features of reactor or cyclotron {alpha}-particles irradiated beryllium microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Khomutov, A M [A.A.Bochvar All-Russia Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Gromov, B F; Karabanov, V N [and others

    1998-01-01

    Studies were carried out into microstructure changes accompanying helium swelling of Be reactor neutron irradiated at 450degC or {alpha}-particles implanted in cyclotron to reach the same volume accumulation of He (6-8 ncm{sup 3} He/cm{sup 3} Be). The microstructures of reactor irradiated and implanted samples were compared after vacuum anneal at 600-800degC up to 50h. The irradiated samples revealed the etchability along the grain boundaries in zones formed by adequately large equilibrium helium pores. The width of the zones increased with the annealing time and after 50h reached 30{mu}. Depleted areas 2-3{mu} dia were observed in some regions of near grain boundary zones. The roles of grain boundaries and manufacturing pores as vacancies` sources and helium sinks are considered. (author)

  2. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1986-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 references, 3 figures, 2 tables

  3. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1985-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, 1/2d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 refs., 3 figs., 2 tabs

  4. Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

    International Nuclear Information System (INIS)

    Ng, C.K.M.; Chong, E.Y.W.; Roy, V.A.L.; Cheung, K.M.C.; Yeung, K.W.K.; Yu, K.N.

    2012-01-01

    We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: ► We proposed a simple method to fabricate micropillar substrates. ► Polyallyldiglycol carbonate films were irradiated and etched to form casts. ► Polydimethylsiloxane replica then formed the micropillar substrates. ► Attachment and proliferation of HeLa cells were enhanced on these substrates.

  5. Detection of alpha particles by means of zinc sulphide screens. Study of their characteristics

    International Nuclear Information System (INIS)

    Gaeta, R.; Manero, F.

    1959-01-01

    A method of SZn(Ag) screens preparation in order to detect alpha particles is described. The behaviour of the luminophore in a scintillometer is primarily studied and followed by experimental methods in the preparation of screens with the specific qualities required. A sedimentation technic of SZn(Ag) deposition has been employed, and followed by pressing in hot. The variation of impulse size with the massif thickness of luminophore has been studied, and found a maximum value for 6,5 mg/cm 2 in unpressed screens and 6 mg/cm 2 in the pressed ones. The plateau curves present flat areas till 450 volts. The background in source absence is below 0.5 impulse/minute. (Author) 19 refs

  6. Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chong, E.Y.W. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Roy, V.A.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Cheung, K.M.C.; Yeung, K.W.K. [Department of Orthopaedics and Traumatology, University of Hong Kong (Hong Kong); Yu, K.N., E-mail: appetery@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2012-07-15

    We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas. - Highlights: Black-Right-Pointing-Pointer We proposed a simple method to fabricate micropillar substrates. Black-Right-Pointing-Pointer Polyallyldiglycol carbonate films were irradiated and etched to form casts. Black-Right-Pointing-Pointer Polydimethylsiloxane replica then formed the micropillar substrates. Black-Right-Pointing-Pointer Attachment and proliferation of HeLa cells were enhanced on these substrates.

  7. Gas production due to alpha particle degradation of polyethylene and polyvinylchloride

    International Nuclear Information System (INIS)

    Reed, D.T.; Hoh, J.; Emery, J.; Okajima, S.; Krause, T.

    1998-07-01

    Alpha particle degradation experiments were performed on polyethylene (PE) and polyvinylchloride (PVC) plastic samples typical of Westinghouse Savannah River Company (WSRC) transuranic (TRU) waste. This was done to evaluate the effects of sealing TRU waste during shipment. Experiments were conducted at three temperatures using low dose rates. Predominant products from both plastics were hydrogen, carbon dioxide, and various organic species, with the addition of hydrochloric acid from PVC. In all experiments, the total pressure decreased. Irradiation at 30 and 60 C and at various dose rates caused small changes for both plastics, but at 100 C coupled thermal-radiolytic effects included discoloration of the material as well as large differences in the gas phase composition

  8. Wear behaviour of Armco iron after irradiation with neutrons and alpha particles

    International Nuclear Information System (INIS)

    Szatzschneider, K.

    1977-04-01

    The effects of neutron and alpha particle irradiation on the wear behaviour of Armco iron were studied. For the investigation, a pin-desk test facility was designed and built. From the experiments an influence upon wear of the type of irradiation, and the radiation dose was determined, which, however, cannot be explained - on the basis of existing wear theories - by the change in the macroscopic-mechanical properties of the material. It has again been shown that an indication of the hardness is not sufficient to describe wear. The influence of the history of the material (irradiation, annealing, deformation) is very strong and connot be predicted because of the multiplicity of interdependences. Wear in the low wear area was identified as being due to oxidation, in the high wear area as metallic. (orig./GSC) [de

  9. Assessment of gamma, beta and alpha-particle-emitting nuclides in marine samples

    International Nuclear Information System (INIS)

    Holm, E.

    1997-01-01

    Depending on the physical properties of radionuclides different systems must be used for their measurement. Most convenient is if gamma spectrometry can be used by germanium, Silicon or Scintillation detectors (eg. NaI). If, however, the main emission consists of beta or alpha particles or low-energy photons as is the case for radionuclides decaying by electron capture, radiochemical separation and specific source preparations must be undertaken. In such cases also the radiochemical yield must be determined. The radiochemical part mainly follows the lines presented by prof. T. Jaakkola, Department of Radiochemistry, Helsinki, Finland, at a course in radioecology in Lurid, 1991. For very long-lived radionuclides other methods such as mass spectrometry are superior although often associated with sophisticated expensive instrumentation. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-15

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

  11. [Near infrared distance sensing method for Chang'e-3 alpha particle X-ray spectrometer].

    Science.gov (United States)

    Liang, Xiao-Hua; Wu, Ming-Ye; Wang, Huan-Yu; Peng, Wen-Xi; Zhang, Cheng-Mo; Cui, Xing-Zhu; Wang, Jin-Zhou; Zhang, Jia-Yu; Yang, Jia-Wei; Fan, Rui-Rui; Gao, Min; Liu, Ya-Qing; Zhang, Fei; Dong, Yi-Fan; Guo, Dong-Ya

    2013-05-01

    Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang'E-3 lunar rover, the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present paper will first give a brief introduction to APXS, and then analyze the specific requirements and constraints to realize distance measurement, at last present a new near infrared distance sensing algorithm by using the inflection point of response curve. The theoretical analysis and the experiment results verify the feasibility of this algorithm. Although the theoretical analysis shows that this method is not sensitive to the operating temperature and reflectance of the lunar surface, the solar infrared radiant intensity may make photosensor saturation. The solutions are reducing the gain of device and avoiding direct exposure to sun light.

  12. Alpha Particles and X Rays Interact in Inducing DNA Damage in U2OS Cells.

    Science.gov (United States)

    Sollazzo, Alice; Brzozowska, Beata; Cheng, Lei; Lundholm, Lovisa; Haghdoost, Siamak; Scherthan, Harry; Wojcik, Andrzej

    2017-10-01

    Survivors of the atomic bombings of Hiroshima and Nagasaki are monitored for health effects within the Life Span Study (LSS). The LSS results represent the most important source of data about cancer effects from ionizing radiation exposure, which forms the foundation for the radiation protection system. One uncertainty connected to deriving universal risk factors from these results is related to the problem of mixed radiation qualities. The A-bomb explosions generated a mixed beam of the sparsely ionizing gamma radiation and densely ionizing neutrons. However, until now the possible interaction of the two radiation types of inducing biological effects has not been taken into consideration. The existence of such interaction would suggest that the application of risk factors derived from the LSS to predict cancer effects after pure gamma-ray irradiation (such as in the Fukushima prefecture) leads to an overestimation of risk. To analyze the possible interaction of radiation types, a mixed-beam exposure facility was constructed where cells can be exposed to sparsely ionizing X rays and densely ionizing alpha particles. U2OS cells were used, which are stably transfected with a plasmid coding for the DNA repair gene 53BP1 coupled to a gene coding for the green fluorescent protein (GFP). The induction and repair of DNA damage, which are known to be related to cancer induction, were analyzed. The results suggest that alpha particles and X rays interact, leading to cellular and possibly cancer effects, which cannot be accurately predicted based on assuming simple additivity of the individual mixed-beam components.

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

    Science.gov (United States)

    Garcia, Timothy Richard

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

  14. Radiation and biophysical studies on cells and viruses. Progress report, April 1, 1976--June 30, 1977. [Gamma radiation, alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Cole, A.

    1977-01-01

    Progress is reported on the following research projects: genetic structure of DNA, chromosomes, and nucleoproteins; particle beam studies of radiosensitive sites; division delay in CHO cells induced by partly penetrating alpha particles; location of cellular sites for mutation induction; sites for radioinduced cell transformation using partly penetrating particle beams; gamma-ray and particle irradiation of nucleoproteins and other model systems; quantitation of surface antigens on normal and neoplastic cells by x-ray fluorescence; hyperthermic effects on cell survival and DNA repair mechanisms; and studies on radioinduced cell transformation. (HLW)

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  16. Evaluation of gross radioactivity in foodstuffs

    International Nuclear Information System (INIS)

    Zorer, Oezlem Selcuk; Oeter, Cigdem

    2015-01-01

    The paper presents the results of radiological investigations of food products sampled in the summer and fall of 2011 and 2012 in different parts of Van, Turkey. Gross radioactivity measurements in food products were evaluated. Food items were divided into eight groups: (1) water, (2) fish, (3) cheese products, (4) fruits, (5) vegetables, (6) herbs, (7) walnut and (8) rock salt. The levels of the gross alpha and gross beta radioactivity in all food samples varied widely ranging from 0.070 to 10.885 Bq/g and from 0.132 to 48.285 Bq/g on dry mass basis, respectively. In one sample, gross alpha and gross beta activity concentrations were found to be relatively high according to the other samples and in all samples, the gross alpha radioactivity was measured lower than the gross beta radioactivity. The gross α and gross β activities were measured by using α/β counter of the multi-detector low background system (PIC MPC-9604).

  17. Evaluation of gross radioactivity in foodstuffs

    Energy Technology Data Exchange (ETDEWEB)

    Zorer, Oezlem Selcuk; Oeter, Cigdem [Yuzuncu Yil Univ., Van (Turkey). Dept. of Chemistry

    2015-05-15

    The paper presents the results of radiological investigations of food products sampled in the summer and fall of 2011 and 2012 in different parts of Van, Turkey. Gross radioactivity measurements in food products were evaluated. Food items were divided into eight groups: (1) water, (2) fish, (3) cheese products, (4) fruits, (5) vegetables, (6) herbs, (7) walnut and (8) rock salt. The levels of the gross alpha and gross beta radioactivity in all food samples varied widely ranging from 0.070 to 10.885 Bq/g and from 0.132 to 48.285 Bq/g on dry mass basis, respectively. In one sample, gross alpha and gross beta activity concentrations were found to be relatively high according to the other samples and in all samples, the gross alpha radioactivity was measured lower than the gross beta radioactivity. The gross α and gross β activities were measured by using α/β counter of the multi-detector low background system (PIC MPC-9604).

  18. New features of nuclear excitation by {alpha} particles scattering; Nouveaux aspects de l'excitation nucleaire par diffusion de particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Saudinos, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1962-07-01

    Inelastic scattering of medium energy a particles by nuclei is known to excite preferentially levels of collective character. We have studied the scattering of isotopically enriched targets of Ca, Fe, Ni, Cu, Zn. In part I, we discuss the theoretical features of the interaction. In part II, we describe the experimental procedure. Results are presented and analysed in part III. {alpha} particles scattering by Ca{sup 40} is showed to excite preferentially odd parity levels. In odd nuclei we have observed multiplets due to the coupling of the odd nucleon with the even-even core vibrations. For even-even nuclei, a few levels are excited with lower cross-sections between the well-known first 2{sup +} and 3{sup -} states. Some could be members of the two phonon quadrupole excitation and involve a double nuclear excitation process. (author) [French] On sait que la diffusion inelastique des particules alpha de moyenne energie excite preferentiellement des niveaux de caractere collectif. Nous avons etudie la diffusion des particules alpha de 44 MeV du cyclotron de Saclay par des isotopes separes de Ca, Fe, Ni, Cu, Zn. Dans la premiere partie nous exposons les theories de cette interaction. Dans la seconde nous decrivons le systeme experimental. Les resultats sont donnes dans la troisieme partie. Nous montrons que les niveaux excites preferentiellement pour {sup 40}Ca par diffusion ({alpha},{alpha}') sont de parite negative. Dans les noyaux pair-impair nous avons observe des multiplets dus au couplage du nucleon celibataire avec les vibrations du coeur pair-pair. Pour les noyaux pair-pair nous avons pu etudier entre le premier niveau 2{sup +} et le niveau 3{sup -} deja bien connus certains etats plus faiblement excites. Il semble qu'ils sont dus a une excitation quadrupolaire a deux phonons et impliquent un processus de double excitation nucleaire. (auteur)

  19. Determination of radon daughter activities of different aerosol fractions by gross-α and gross-β measurements

    International Nuclear Information System (INIS)

    Katona, T.; Kanyar, B.; Jobbagy, V.; Kavasi, N.; Molnar, A.; Imre, K.

    2004-01-01

    The aim was to determine the radioactivities of the radon progenies ( 218 Po, 214 Pb, 214 Bi and 214 Po) attached to the carrier aerosol particles with respect to the size distribution in order to improve the assessment of the inhalation dose. We derived the radionuclide-specific activity concentrations from gross alpha and gross beta measurements provided during 2 hours after sampling and model calculations including parameter estimation. For the aerosol sampling we used an electrical low pressure impactor, which is able to collect aerosol particles in 12 different diameter ranges. In our test investigations the aerosol particles were collected from a closed chamber in a common laboratory building. The chamber contained a relatively high radon concentration (60-90 kBq/m 3 ) in equilibrium with the short lived daughters generated previously without any additional aerosol sources. For the nuclear measurements of the aerosol samples ZnS/plastic sandwich detectors have been used. The time series data of gross alpha and gross beta activities were fitted simultaneously and the initial activities of the daughters were estimated. According to the results from two different fractions (0.06 and 0.7 μm) just followed the end of sampling they contain a higher 218 Po activity than the 214 Pb and 214 Bi ones. The preliminary assessments for the special air conditions show that the 214 Pb-to- 218 Po activity ratios are higher for the small aerosol particles than for the larger ones. The estimated errors of the initial activities were near to 50% in a large part of cases. (author)

  20. Astrophysics and particle physics in space with the Alpha Magnetic Spectrometer

    CERN Document Server

    Lamanna, G

    2003-01-01

    The Alpha Magnetic Spectrometer is a high energy particle physics experiment in space scheduled to be installed on the International Space Station (ISS) by 2006 for a three-year mission. After a precursor flight of a prototype detector on board of the NASA Space Shuttle in June 1998, the construction of the detector in its final configuration is started and it will be completed by 2004. The purpose of this experiment is to provide a high statistics measurement of charged particles and nuclei in rigidity range 0.5 GV to few TV and to explore the high-energy (>1 GeV) gamma-ray sky. In this paper we describe the detector layout and present an overview of the main scientific goals both in the domain of astrophysics: cosmic- ray origin, age and propagation and the exploration of the most energetic gamma-ray sources; and in the domain of astroparticle: the antimatter and the dark matter searches. (53 refs).

  1. Characterization of compositional modifications in metal-organic frameworks using carbon and alpha particle microbeams

    Science.gov (United States)

    Paneta, V.; Fluch, U.; Petersson, P.; Ott, S.; Primetzhofer, D.

    2017-08-01

    Zirconium-oxide based metal-organic frameworks (MOFs) were grown on p-type Si wafers. A modified linker molecule containing iodine was introduced by post synthetic exchange (PSE). Samples have been studied using Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) techniques, employing the 5 MV 15SDH-2 Pelletron Tandem accelerator at the Ångström laboratory. The degree of post synthetic uptake of the iodine-containing linker has been investigated with both a broad beam and a focused beam of carbon and alpha particles targeting different kind of MOF crystals which were of ∼1-10 μm in size, depending on the linker used. Iodine concentrations in MOF crystallites were also measured by Nuclear Magnetic Resonance Spectroscopy (NMR) and are compared to the RBS results. In parallel to the ion beam studies, samples were investigated by Scanning Electron Microscopy (SEM) to quantify possible crystallite clustering, develop optimum sample preparation routines and to characterize the potential ion beam induced sample damage and its dependence on different parameters. Based on these results the reliability and accuracy of ion beam data is assessed.

  2. Design of a preamplifier for an alpha particles spectrometer; Diseno de un preamplificador para un espectrometro de particulas alfa

    Energy Technology Data Exchange (ETDEWEB)

    Murillo O, R.; Hernandez D, V. M.; Chacon R, A.; Vega C, H. R., E-mail: fermineutron@yahoo.co [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2010-09-15

    To detect radiation diverse detector types are used, when these are alpha particles proportional type detectors are used, semiconductor, of scintillation or traces. In this work the design results, the construction and the first tests of a spectrometer (preamplifier) are presented for alpha particles that was designed starting from a Pin type photodiode. The system was designed and simulated with a program for electronic circuits. With the results of the simulation phase was constructed the electronics that is coupled to a spectroscopic amplifier and a multichannel analyzer. The total of the system is evaluated analyzing its performance before a triple source of alphas and that they are produced by two smoke detectors of domestic use. Of the tests phase we find that the system allows to obtain in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  3. Excitation functions for alpha-particle-induced reactions with natural antimony

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N. L.; Shah, D. J.; Mukherjee, S.; Chintalapudi, S. N. [Vadodara, M. S. Univ. of Baroda (India). Fac. of Science. Dept. of Physics

    1997-07-01

    Stacked-foil activation technique and {gamma} - rays spectroscopy were used for the determination of the excitation functions of the {sup 121}Sb [({alpha}, n); ({alpha}, 2n); ({alpha},4 n); ({alpha}, p3n); ({alpha}, {alpha}n)]; and Sb [({alpha}, 3n); ({alpha}, 4n); ({alpha}, {alpha}3n)] reactions. The excitation functions for the production of {sup 124}I, {sup 123}I, {sup 121}I, {sup 121}Te and {sup 120}Sb were reported up to 50 MeV. The reactions {sup 121} Sb ({alpha}, {alpha}n) + {sup 123} Sb ({alpha}, {alpha}3n) are measured for the first time. Since natural antimony used as the target has two odd mass stable isotopes of abundances 57.3 % ({sup 121}Sb), their activation in some cases gives the same product nucleus through different reaction channels but with very different Q-values. In such cases, the individual reaction cross-sections are separated with the help of theoretical cross-sections. The experimental cross-sections were compared with the predictions based on hybrid model of Blann. The high-energy part of the excitation functions are dominated by the pre-equilibrium reaction mechanism and the initial exciton number n{sub 0} = 4 (4 p 0 h) gives fairly good agreement with presently measured results.

  4. Thresholds and Q values of nuclear reactions induced by neutrons, protons, deuterons, tritons, 3He ions, alpha particles, and photons

    International Nuclear Information System (INIS)

    Howerton, R.J.

    1981-01-01

    The 1977 Wapstra and Bos nuclear mass data tables were used to derive tables for thresholds and Q values of nuclear reactions induced by neutrons, protons, deuterons, tritons, 3 He ions, alpha particles, and photons. The tables are displayed on microfiche included with the report

  5. Measurements of the light conversion efficiency of lithium borate for alpha particles relative to cobalt-60 gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, D.T.; Wall, B.F.; Fisher, E.S. (National Radiological Protection Board, Harwell (UK))

    1982-01-01

    The results are reported of measurements of the light conversion efficiencies of lithium borate TLD phosphor of British Nuclear Fuels Ltd. manufacture to 5.65 MeV and 2.4 MeV alpha particles relative to /sup 60/Co gamma radiation.

  6. Micronuclei in human peripheral blood lymphocytes exposed to mixed beams of X-rays and alpha particles

    Czech Academy of Sciences Publication Activity Database

    Staaf, E.; Brehwens, K.; Haghdoost, S.; Nievaart, S.; Pachnerová Brabcová, Kateřina; Czub, J.; Braziewicz, J.; Wojcik, A.

    2012-01-01

    Roč. 51, č. 3 (2012), s. 283-293 ISSN 0301-634X Institutional research plan: CEZ:AV0Z10480505 Keywords : Micronuclei * LET * Combined exposure * Mixed beams * Alpha particles * X-rays Subject RIV: BO - Biophysics Impact factor: 1.754, year: 2012

  7. Hauser-Feshbach cross-section calculations for elastic and inelastic scattering of alpha particles-program CORA

    International Nuclear Information System (INIS)

    Hartman, A.; Siemaszko, M.; Zipper, W.

    1975-01-01

    The program CORA was prepared on the basis of Hauser and Feshbach compound reaction formalism. It allows the differential cross-section distributions for the elastic and inelastic scattering of alpha particles (via compound nucleus state) to be calculated. The transmission coefficients are calculated on the basis of a four parameter optical model. The search procedure is also included. (author)

  8. Uranium trace and alpha activity characterization of coal and fly ash using particle track etch technique

    International Nuclear Information System (INIS)

    Chakravarti, S.K.

    1991-01-01

    Uranium is extensively found in carbonaceous components of sedimentary rocks and is considered to be accumulated in coals during the coalification process through the geological times. Burning of coal is mainly responsible for a manifold increase in the concentration of radioactive nuclides in atmosphere precipitates. Fly ash being an incombustible residue and formed from 90% of the inorganic material in coal, escapes into the atmosphere and constitutes a potential hazard. Also its use as one of the pozzolanic materials in the products of concrete, bricks etc and filling of ground cavities is even more hazardous because of the wall radioactivity, besides emission and diffusion of radon. This paper reports a simple method called Particle Track Etch (PTE) technique, for trace determination of uranium content in coal and fly ash samples by making use of low cost and versatile plastic detectors known as Solid State Nuclear Track Detectors (SSNTDs). Total alpha activity has also been estimated using these SSNTDs. The values of uranium concentration in coal samples are found to range from 1.1 to 3.6 ppm (uniform component) and 33 to 46 ppm (non-uniform part) whereas in fly ash, it varies from 8 to 11 ppm (uniform) and 55 to 71 ppm in non-uniform range. It is also observed that the alpha activity is a function of uranium concentration for most of the natural samples of coal studied except for mixtures of fly ash samples where relationship is found to be on higher side. (author). 13 refs., 2 tabs., 1 fig

  9. Influences of target geometry on the microdosimetry of alpha particles in water

    International Nuclear Information System (INIS)

    Huston, T.E.

    1992-01-01

    Application of microdosimetric concepts to radiation exposure situations requires knowledge of the single-event density function, f 1 (z) , where z denotes specific energy imparted to target matter. Multiple-event density functions are calculated by taking convolutions of f 1 (z) with itself with the overall specific energy density function is then found by employing a compound Poisson process involving single and multiple-event spectra. The f l (z), depends strongly on the geometric details of a the source, target, and all intermediate matter. While most past applications of microdosimetry have been represented targets as spheres, may be better modeled as prolate or oblate spheroids. Using a ray-tracing technique coupled with a continuous-slowing-down approximation, methods are developed and presented for calculating single-event density functions for spheroidal targets irradiated by alpha-emitting point sources. Computational methods are incorporated into a fortran computer code entitled SEROID (single-event density functions for spheroids), which is listed in this paper. This was used to generate several single-event density functions, along with related means and standard deviations in specific energy, for spheroidal targets irradiated by alpha particles. Targets of varying shapes and orientations are examined. Results for non-spherical targets are compared to spherical targets of equal volume in order to assess influences which target geometry has on single-event quantities. From these comparisons it is found that both target shape and orientation are important in adequately characterizing the quantities examined in this study; over-simplifying the target geometry can lead to substantial error

  10. An alpha particle detector based on a GPS mosaic scintillator plate for continuous air monitoring in plutonium handling facilities

    International Nuclear Information System (INIS)

    Kaneko, Junichi H.; Izaki, Kenji; Toui, Kouhei; Shimaoka, Takehiro; Morishita, Yuki; Tsubota, Youichi; Higuchi, Mikio

    2016-01-01

    An alpha particle detector was developed for continuous air monitoring of radioactive contamination in working chambers at plutonium handling facilities. A 5-cm-square Gd 2 Si 2 O 7 :Ce (cerium-doped gadolinium pyro-silicate, GPS:Ce) mosaic scintillator plate for alpha particle measurements was fabricated from GPS single-crystal grains of around 550 μm diameter; the GPS grains were made of a GPS polycrystalline body grown using a top seeded solution method. The scintillator layer thickness was approximately 100 μm. The surface filling rate of the GPS grains was ca. 62%. To suppress the influence of non-uniformity of pulse heights of a photomultiplier tube, a central part of ∅ 40 mm of a 76-mm-diameter photomultiplier tube was used. In addition, 3 mm thick high-transmission glass was used as a substrate of the scintillator plate. The detector achieved energy resolution of 13% for 5.5 MeV alpha particles, detection efficiency of 61% and a radon progeny nuclide reduction ratio of 64.5%. A new alpha particle detector was developed to achieve a high radon progeny nuclide reduction ratio approaching that of a silicon semiconductor detector, with high resistance to electromagnetic noise and corrosion. - Highlights: • An alpha particle detector was developed for continuous air monitoring. • The detector comprises a mosaic scintillator plate and a photomultiplier tube. • A 5-cm-square GPS mosaic scintillator plate was fabricated. • Its respective energy resolution and detection efficiency were 13 and 61%. • The radon progeny nuclide reduction ratio of the developed detector was 64.5%.

  11. Coincidence measurement between. cap alpha. -particles and projectile-like fragments in reaction of 82. 7 MeV /sup 16/O on /sup 27/Al

    Energy Technology Data Exchange (ETDEWEB)

    Wen-Qing, Shen; Wen-long, Zhan; Yong-tai, Zhu; Shu-zhi, Yin; Zhong-yan, Guo; Wei-min, Qiao; Guo-ying, Fan; Gen-ming, Jin; Song-ling, Li; Zhen, Zhang; others, and

    1987-01-01

    In the coincidence measurement between ..cap alpha..-particles and projectile-like fragments in the reaction of 82.7 MeV /sup 16/O on /sup 27/Al, the contour plot of the C-..cap alpha.. coincidence in the velocity plane and the coincident angular correlation are obtained. Different mechanisms of ..cap alpha..-particle emission are analysed. A possible reaction mechanism of incomplete DIC is discussed.

  12. Alpha spectrometric characterization of process-related particle size distributions from active particle sampling at the Los Alamos National Laboratory uranium foundry

    Energy Technology Data Exchange (ETDEWEB)

    Plionis, Alexander A [Los Alamos National Laboratory; Peterson, Dominic S [Los Alamos National Laboratory; Tandon, Lav [Los Alamos National Laboratory; Lamont, Stephen P [Los Alamos National Laboratory

    2009-01-01

    Uranium particles within the respirable size range pose a significant hazard to the health and safety of workers. Significant differences in the deposition and incorporation patterns of aerosols within the respirable range can be identified and integrated into sophisticated health physics models. Data characterizing the uranium particle size distribution resulting from specific foundry-related processes are needed. Using personal air sampling cascade impactors, particles collected from several foundry processes were sorted by activity median aerodynamic diameter onto various Marple substrates. After an initial gravimetric assessment of each impactor stage, the substrates were analyzed by alpha spectrometry to determine the uranium content of each stage. Alpha spectrometry provides rapid nondestructive isotopic data that can distinguish process uranium from natural sources and the degree of uranium contribution to the total accumulated particle load. In addition, the particle size bins utilized by the impactors provide adequate resolution to determine if a process particle size distribution is: lognormal, bimodal, or trimodal. Data on process uranium particle size values and distributions facilitate the development of more sophisticated and accurate models for internal dosimetry, resulting in an improved understanding of foundry worker health and safety.

  13. A study of some lattice defects with help of channeled {alpha} particles; Etude de quelques defauts cristallins a l'aide de particules {alpha} canalisees

    Energy Technology Data Exchange (ETDEWEB)

    Quere, Y [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    A method is described in which a metallic foil is irradiated by isotropic {alpha} particles. The thickness of the foil is such that only channeled particles can traverse it. The emerging flux, a function of the local concentration of defects, falls on a collector where an image of the foil is formed. The influence of grain or twin boundaries, of stacking faults, of dislocations, is observed. A quantitative study of dislocation is presented. The effect of a dislocation is represented by the presence of a coaxial dechanneling-cylinder of diameter: {lambda}-bar = [(b d a E)/({alpha}Z{sub 1}Z{sub 2}e{sup 2})]{sup 1/2}, b is the Burgers vector; d the interatomic distance along the channel; a the screening radius of the interaction between the particles (Z{sub 2}) and the metal (Z{sub 1} ); E the energy of the particles; {alpha} a numerical parameter. There is a reasonable agreement with experimental results. Channeling patterns, observed in all metals, are described. They are more numerous if the metal has been treated some time in gaseous atmospheres. They correspond to zones, on the metal, situated on the side of entrance of particles. It is proposed that in these zones, gaseous atoms strengthen the channels and enhance channeling. (author) [French] On decrit une methode qui consiste a irradier une feuille metallique par des particules {alpha} isotropes. La feuille est assez epaisse pour que seules les particules canalisees emergent. Le flux sortant depend alors fortement de la concentration en defauts. Il est recueilli sur un collecteur ou se forme ainsi une image de l'echantillon. On montre l'influence des joints de grains ou de macle, des fautes d'empilement et des dislocations. Dans ce dernier cas, la methode se prete bien a des etudes quantitatives. On represente l'effet d'une dislocation par la presence d'un cylindre de decanalisation coaxial de diametre: {lambda}-bar = [(b d a E)/({alpha}Z{sub 1}Z{sub 2}e{sup 2})]{sup 1/2} ou b est le vecteur de Burgers, d la

  14. Use of track-end alpha particles from 241Am to study radiosensitive sites in CHO cells

    International Nuclear Information System (INIS)

    Datta, R.; Cole, A.; Robinson, S.

    1976-01-01

    Monolayers of CHO cells placed on membrane filters were irradiated with alpha particles from a 241 Am source. Particle penetration into the cells was controlled by placing the cell sample at various distances from the source. Dosimetric and spectrometric measurements were performed at comparable positions using a parallel plate ionization chamber and a scintillation crystal spectrometer. Cell survival, as measured by conventional cloning techniques, was single hit in form. A pronounced minimum in mean lethal dose of 29 rad was observed for alpha particle beams that penetrated only about 3 μm into the cell. A pronounced maximum in inactivation cross section of 90 μm 2 , equal to about half the projected area of the nucleus, occurred for beams that penetrated only 5 to 7 μm into the cell. Thus, a single alpha particle penetration several micrometers within the cell nucleus was effective in killing the cell, while fully penetrating beams were actually less efficient; the latter beams required multiple particle traversals and about three times the cell dose to achieve the same effect. These results support the proposal that radiosensitive sites are located in a thin peripheral region of the nucleus

  15. The effects of intense gamma-irradiation on the alpha-particle response of silicon carbide semiconductor radiation detectors

    International Nuclear Information System (INIS)

    Ruddy, Frank H.; Seidel, John G.

    2007-01-01

    Silicon Carbide (SiC) semiconductor radiation detectors are being developed for alpha-particle, X-ray and Gamma-ray, and fast-neutron energy spectrometry. SiC detectors have been operated at temperatures up to 306 deg. C and have also been found to be highly resistant to the radiation effects of fast-neutron and charged-particle bombardments. In the present work, the alpha-particle response of a SiC detector based on a Schottky diode design has been carefully monitored as a function of 137 Cs gamma-ray exposure. The changes in response have been found to be negligible for gamma exposures up to and including 5.4 MGy, and irradiations to higher doses are in progress

  16. Transport theory for energetic alpha particles and tolerable magnitude of error fields in tokamaks with broken symmetry

    International Nuclear Information System (INIS)

    Shaing, K.C.; Hsu, C.T.

    2014-01-01

    A transport theory for energetic fusion born alpha particles in tokamaks with broken symmetry has been developed. The theory is a generalization of the theory for neoclassical toroidal plasma viscosity for thermal particles in tokamaks. It is shown that the radial energy transport rate can be comparable to the slowing down rate for energetic alpha particles when the ratio of the typical magnitude of the perturbed magnetic field strength to that of the equilibrium magnetic field strength is of the order of 10 −4 or larger. This imposes a constraint on the magnitude of the error fields in thermonuclear fusion reactors. The implications on stellarators as potential fusion reactors are also discussed. (paper)

  17. Detection of {alpha} particles using semiconductors. Application to the control of plutonium extraction; Detection des particules {alpha} par semiconducteurs application au controle de l'extraction du plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Tanguy, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-03-01

    A study is made of a particles produced by thick sources, using either diffused junction or surface barrier semiconductor detectors for controlling continuously the plutonium extraction process. For this, a presenting apparatus is described in which the solutions to be analyzed flow in contact with the detector protected by a thin mica membrane. A method is described which gives a precise recording of the spectra and which thus allows the separation of two or more {alpha} emitters present in the same solution. This method has been applied to the measurement of {sup 239}Pu in the the presence of {sup 241}Am with an accuracy of {+-}5 per cent. In the second part of the report is considered the detection of plutonium in solutions of {beta} - {gamma} emitting fission products. Pile-up is reduced by using a fast amplification chain associated to totally depleted thin detectors. Under these conditions a few mg of {sup 239}Pu can be detected in solutions of fission products having an activity of 100 curies/liter. A method is given for discriminating {alpha} and {beta} particles, it is based on the difference in the collection times for the charges liberated by these particles in the detector. (author) [French] On etudie la detection de particules {alpha} issues de sources epaisses par detecteurs semiconducteurs a jonction diffusee ou a barriere de surface pour le controle continu du procede d'extraction du plutonium. A cet effet on decrit un appareil presentateur dans lequel les solutions a analyser circulent au contact du detecteur protege par une membrane mince de mica. On decrit une methode qui permet par le trace precis des spectres de separer deux ou plusieurs emetteurs {alpha} presents dans une meme solution. Cette methode a ete appliquee a la mesure du {sup 239}Pu en presence de {sup 241}Am avec une precision de {+-} 5 pour cent. Dans la deuxieme partie on traite de la detection du plutonium dans des solutions de produits de fission emetteurs {beta} and {gamma}. On

  18. Development of thin foil Faraday collector as a lost alpha particle diagnostic for high yield D-T tokamak fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Van Belle, P; Jarvis, O N; Sadler, G J [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Cecil, F E [Colorado School of Mines, Golden, CO (United States)

    1994-07-01

    Alpha particle confinement is necessary for ignition of a D-T tokamak fusion plasma and for first wall protection. Due to high radiation backgrounds and temperatures, scintillators and semiconductor detectors may not be used to study alpha particles which are lost to the first wall during the D-T programs on JET and ITER. An alternative method of charged particle spectrometry capable of operation in these harsh environments, is proposed: it consists of thin foils of electrically isolated conductors with the flux of alpha particles determined by the positive current flowing from the foils. 2 refs., 3 figs.

  19. Alpha-particle autoradiography in CR-39: a technique for quantitative assessment of alpha-emitters in biological tissue

    International Nuclear Information System (INIS)

    Fews, A.P.; Henshaw, D.L.

    1983-01-01

    The techniques for α-particle autoradiography based on the plastic nuclear track detector CR-39, previously reported, have been developed considerably. The techniques are applied to α-autoradiography of human lung tissue in particular but are applicable to any biological tissue. The most important developments are: (i) Improvements in the manufacture and pre-etching of the plastic. (ii) High resolution α-particle spectroscopy in CR-39 plastic based on the analysis of the structure of the etched track. (iii) Calculation of the effective thickness of tissue sampled by the plastic. (iv) A deconvolution analysis which takes the distributions of track length and dip angle in the plastic and determines the α-particle range spectrum and distribution of tissue activity with height above the plastic surface. (v) The analysis of radon diffusion in tissue to determine the mean radon diffusion distance in tissue and plastic. (author)

  20. Metallothionein bioconjugates as delivery vehicles for bismuth-212 alpha particle therapy

    International Nuclear Information System (INIS)

    Macklis, R.M.; Morris, C.; Humm, J.; Hines, J.; Atcher, R.

    1991-01-01

    Metallothioneins (MTHs) are small cysteine-rich polypeptides that binds cationic metals at physiologic pH ranges through noncovalent -SH ligand interactions. Some leucine-rich renal MTHs have a particular avidity for bismuth. The authors have examined the ability of MTHs to selectively incorporate Bi-212, a short-lived high-energy alpha particle emitter currently under exploration as a potential therapeutic radiolabel for use in molecularly targeted cancer therapy. They find that under physiologic conditions, MTH will selectively incorporate Bi-212 after incubation with an equilibrium mixture of its upstream and downstream parents. The MTH moieties may be linked to tumor-binding macromolecules such as antibodies via thiolation reactions using SPDP, and the resultant Bismuth-avid molecules may be used either as primary delivery vehicles for the Bi-212 or as part of a 2-step release-and-catch isotope localization system in which the MTH-antibody conjugate is pre-localized at the tumor site and the radiometal is then administered and chelated in situ. They present the chemistry, dosimetry and potential clinical applications of this system

  1. Alpha particle spectroscopy for CR-39 detector utilizing matrix of energy equations

    Energy Technology Data Exchange (ETDEWEB)

    Awad, E.M. [Department of General Sciences, Yanbu Industrial College, PO Box 30436, Madinat Yanbu Al-Sinaiya (Saudi Arabia); Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)], E-mail: ayawad@yahoo.com; Soliman, A.A. [Department of Mathematics, Faculty of Education (AL-Arish), Suez Canal University, AL-Arish 45111 (Egypt); Department of Mathematics, Teacher' s College (Bisha), King Khalid University, Bisha, PO Box 551 (Saudi Arabia)], E-mail: asoliman_99@yahoo.com; Rammah, Y.S. [Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)

    2007-10-01

    A method for determining alpha-particle energy using CR-39 detector by utilizing matrix of energy equation was described. The matrix was composed from two axes; the track minor axis (m) and diameter of etched out track end (d) axis of some selected elliptical tracks. The energy E in (m,d) coordinate was approximated by matrix of energy equations given by: E{sub k}={sigma}{sub i,j=0}{sup 2}a{sub ij}d{sub k}{sup i}m{sub k}{sup j}, which was identified using two different approaches. First, i and j were treated as power exponents for d and m. The adjusting parameters values a{sub ij} were obtained and the energy of a given track was deduced directly from it. Second, i and j were treated as indices of some chosen tracks that were fitted to obtain iso-energy curves that were superimposed on m-d scatter plot as calibration curves. The energy between any two successive iso-energy curves in this case was assumed varied linearly with d for a given m. The energy matrix in both cases was solved numerically. Results of the two approaches were compared.

  2. Local energy deposited for alpha particles emitted from inhaled radon daughters

    International Nuclear Information System (INIS)

    Al-affan, I.A.M.; Haque, A.K.M.M.

    1989-01-01

    An analytical method has been developed to calculate the local energy deposited by alpha particles emitted from radon daughters deposited on the mucus surface in the lung airways. For the particular case of 218 Po (Ra A) and 214 Bi (Ra C'), microdose spectra have been evaluated in test spheres of 1 μm diameter which were taken to lie within airways of diameters 18 000, 3500 and 600 μm. In each case, the contributions of the near and far wall were computed separately. The average microdosimetric parameters y-bar F and y-bar D have also been calculated. For the two smaller airways, y-bar F and y-bar D values were found to be about 110 and 135 keV μm -1 for 218 Po and about 87 and 107 keV μm -1 for 214 Bi respectively. The corresponding values were about 10% higher for the largest airway. (author)

  3. Range-energy relations and stopping powers of organic liquids and vapours for alpha particles

    International Nuclear Information System (INIS)

    Akhavan-Rezayat, A.; Palmer, R.B.J.

    1980-01-01

    Experimental range-energy relations are presented for alpha particles in methyl alcohol, propyl alcohol, dichloromethane, chloroform and carbon tetrachloride in both the liquid and vapour phases. Stopping power values for these materials and for oxygen gas over the energy range 1.0-8.0 MeV are also given. From these results stopping powers have been derived for the -CH 2 -group and for -Cl occurring in chemical combination in the liquid and vapour phases. The molecular stopping power in the vapour phase is shown to exceed that in the liquid phase by 2-6% below 2 MeV, reducing to negligible differences at about 5 MeV for the materials directly investigated and for the -Cl atom. No significant phase effect is observed for the -CH 2 -group, but it is noted that the uncertainties in the values of the derived stopping powers are much greater in this case. Comparison of the experimental molecular stopping powers with values calculated from elemental values using the Bragg additivity rule shows agreement for vapours but not for liquids. (author)

  4. Light charged particle production in fast neutron-induced reactions on carbon (En=40 to 75 MeV) (II). Tritons and alpha particles

    International Nuclear Information System (INIS)

    Dufauquez, C.; Slypen, I.; Benck, S.; Meulders, J.P.; Corcalciuc, V.

    2000-01-01

    Double-differential cross sections for fast neutron-induced triton and alpha-particle production on carbon are reported at six incident neutron energies between 40 and 75 MeV. Angular distributions were measured at laboratory angles between 20 deg. and 160 deg. . Energy-differential, angle-differential and total cross sections are also reported. Experimental cross sections are compared to existing experimental data and to theoretical model calculations

  5. Enhancement of alpha particles-induced cell transformation by oxygen free radicals and tumor necrosis factor released from phagocytes

    International Nuclear Information System (INIS)

    Gong Yifen; Guo Renfeng; Zhu Maoxiang; Shou Jiang; Ge Guixiu; Yang Zhihua; Hieber, L.; Peters, K.; Schippel, C.

    1997-01-01

    To illustrate the role of several endogenous factors released from phagocytes under chronic inflammation in radiation-induced cancer. C 3 T 10 T 1/2 and SHE cells were used as targets, and 238 Pu alpha source was used in alpha irradiation. The enhancement of TF in alpha particles-induced cell transformation by PMA-stimulated human blood and zymosan-stimulated U-937 cells was studied using formation of transformed foci. Transformation frequency (TF) of C 3 H 10 T 1/2 cells exposed to alpha particles of 0.5 Gy increased 2.1 and 2.8 fold by PMA-and PMA-stimulated neutrophils, respectively. TF of irradiated SHE cells at a dose of 0.5 Gy increased 12 fold by the addition of the supernatant of macrophage-like U-937 cell line. It was shown that TF of irradiated SHE cells at above dose increased 8 fold by the supernatant treated with anti-TNF-α could be subcultured continuously in vitro. The cells at 40 th passage and two lines of monoclone cells have the ability to develop malignant tumors in nude mice. The overdose of free radicals and TNF-α released from neutrophils and macrophages have played an important role in low dose radiation-induced cancer

  6. Study of the stopping power and straggling for alpha particles and protons in organic solids, liquids and gases

    International Nuclear Information System (INIS)

    Haque, A.K.M.; Mohammadi, A.; Nikjoo, H.

    1985-01-01

    The stopping power and straggling for 5.5 MeV alpha particles in liquid and vapour phases of water, methanol, ethanol, propanol, h-hexane, n-octane and cyclohexane, and those for low energy protons in ethylene, styrene and propylene and their polymers, have been measured. Range-energy data have been fitted with inverse stopping power functions to give the cross sections. In each case, five parameters have been adjusted to obtain the best fit. The value of chi-squared per degree of freedom has been calculated, together with the parameters. The theoretical stopping cross section has been considered employing the Bethe-Bloch expression together with various corrections (shell correction using Walske and Bichsel procedure, Z 1 3 contribution according to Ashley and Bloch correction based on Lindhard formalism). The existence of a phase effect has been clearly demonstrated for the stopping of both alpha particles and protons. (author)

  7. Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

    International Nuclear Information System (INIS)

    Law, Y.L.; Yu, K.N.

    2009-01-01

    In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

  8. Study of influence of catechins on bystander responses in alpha-particle radiobiological experiments using thin PADC films

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    In this study, Chinese hamster ovary (CHO) cells were cultured in custom-made petri dishes with thin PADC films as substrates. Alpha particles with energies of 5 MeV were then irradiated from the bottom of PADC films. The DNA strand breaks in the bystander cells induced by irradiation were quantified with the use of terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay. To study the influence of catechins on the bystander responses, catechins were added into the medium before alpha-particle irradiation of the cells. Fewer DNA strand breaks in the bystander cells were observed. As catechins are ROS (reactive oxygen species)-scavengers, the studied bystander cells might have been protected from radiation through scavenging of ROS by catechins.

  9. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles. Final performance technical report

    International Nuclear Information System (INIS)

    Zaider, M.

    1997-01-01

    The goal of this project was to develop theoretical/computational tools for evaluating the risks incurred by populations exposed to radon alpha particles. Topics of concern include the following: compound dual radiation action (general aspects); a mathematical formalism describing the yield of radiation induced single-and double-strand DNA breaks, and its dependence on radiation quality; a study of the excited states in cytosine and guanine stacks in the Hartree-Fock and exciton approximations; nanodosimetry of radon alpha particles; application of the HSEF to assessing radiation risks in the practice of radiation protection; carcinogenic risk coefficients at environmental levels of radon exposures: a microdosimetric approach; and hit-size effectiveness approach in radiation protection

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  11. Alpha-particle irradiation induced defects in SiO2 films of Si-SiO2 structures

    International Nuclear Information System (INIS)

    Koman, B.P.; Gal'chynskyy, O.V.; Kovalyuk, R.O.; Shkol'nyy, A.K.

    1996-01-01

    The aim of the work was to investigate alpha-particle irradiation induced defects in Si-SiO 2 structures by means of the thermostimulated discharge currents (TSDC) analysis. The object of investigation were (p-Si)-SiO 2 structures formed by a combined oxidation of the industrial p-Si wafers in dry and wet oxygen at temperature of 1150 C. The TSD currents were investigated in the temperature range between 90 and 500 K under linear heating rate. Pu 238 isotopes were the source of alpha-particles with an energy of 4-5 MeV and a density of 5.10 7 s -1 cm -2 . The TSD current curves show two peculiar maxima at about 370 and 480 K. Alpha-particle irradiation doesn't affect the general shape of the TSDC curves but leads to a shift of the maximum at 370 K and reduces the total electret charge which is accumulated in the Si-SiO 2 structures during polarization. The energy distribution function of the defects which are involved in SiO 2 polarization has been calculated. It showes that defects with activation energies of about 0.8 and 1.0 eV take part in forming the electret state, and these activation energies have certain energy distributions. It has been found that the TSDC maximum at 370 K has space charge nature and is caused by migration of hydrogen ions. In irradiated samples hydrogen and natrium ions localize on deeper trapping centres induced by alpha-particle irradiation. (orig.)

  12. Possibility of studying the activity of rocks by the observation of. cap alpha. -particle tracks in a photographic emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Curie, I

    1946-01-01

    A detailed discussion is presented on the possibility of determining the uranium and thorium content of ordinary rocks by observing ..cap alpha..-particle tracks in a photographic film applied to the rocks' surface. Such determinations can be made only where radioactive equilibrium can be assumed. For the examination of normal granite, exposures of several months are needed. The same method can be used to study the distribution of radioactive elements within the rock.

  13. Determining of the track parameters in solid state nuclear track detectors Cr 39 due to alpha particles

    International Nuclear Information System (INIS)

    Kostic, D.; Nikezic, D.

    1997-01-01

    An equation of the etch pit wall is proposed to be used for simulation of the track growth and calculating the major and the minor axis of etch pit opening. Dependence on the following parameters is set up: distance along a track from the point where the particle entered the detector, ratio of the track etch wall to the bulk etch rate, integration constant determined from particle penetration depth and normal distance from the particle trajectory to the etch pit wall. The corresponding computer program was written. The input parameters of this program are: alpha particles energy, incidence angle and removed layer; the output gives track parameters. The results obtained by this method are compared to another approach given by Somogy and Szalay (1973) and a reasonably good agreement is found. (author)

  14. Calibration of a Thomson parabola ion spectrometer and Fujifilm imaging plate detectors for protons, deuterons, and alpha particles.

    Science.gov (United States)

    Freeman, C G; Fiksel, G; Stoeckl, C; Sinenian, N; Canfield, M J; Graeper, G B; Lombardo, A T; Stillman, C R; Padalino, S J; Mileham, C; Sangster, T C; Frenje, J A

    2011-07-01

    A Thomson parabola ion spectrometer has been designed for use at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) at the University of Rochester. This device uses parallel electric and magnetic fields to deflect particles of a given mass-to-charge ratio onto parabolic curves on the detector plane. Once calibrated, the position of the ions on the detector plane can be used to determine the particle energy. The position dispersion of both the electric and magnetic fields of the Thomson parabola was measured using monoenergetic proton and alpha particle beams from the SUNY Geneseo 1.7 MV tandem Pelletron accelerator. The sensitivity of Fujifilm BAS-TR imaging plates, used as a detector in the Thomson parabola, was also measured as a function of the incident particle energy over the range from 0.6 MeV to 3.4 MeV for protons and deuterons and from 0.9 MeV to 5.4 MeV for alpha particles. The device was used to measure the energy spectrum of laser-produced protons at MTW.

  15. Calibration of a Thomson parabola ion spectrometer and Fujifilm imaging plate detectors for protons, deuterons, and alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, C. G.; Canfield, M. J.; Graeper, G. B.; Lombardo, A. T.; Stillman, C. R.; Padalino, S. J. [Physics Department, SUNY Geneseo, Geneseo, New York 14454 (United States); Fiksel, G.; Stoeckl, C.; Mileham, C.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Sinenian, N.; Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2011-07-15

    A Thomson parabola ion spectrometer has been designed for use at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) at University of Rochester. This device uses parallel electric and magnetic fields to deflect particles of a given mass-to-charge ratio onto parabolic curves on the detector plane. Once calibrated, the position of the ions on the detector plane can be used to determine the particle energy. The position dispersion of both the electric and magnetic fields of the Thomson parabola was measured using monoenergetic proton and alpha particle beams from the SUNY Geneseo 1.7 MV tandem Pelletron accelerator. The sensitivity of Fujifilm BAS-TR imaging plates, used as a detector in the Thomson parabola, was also measured as a function of the incident particle energy over the range from 0.6 MeV to 3.4 MeV for protons and deuterons and from 0.9 MeV to 5.4 MeV for alpha particles. The device was used to measure the energy spectrum of laser-produced protons at MTW.

  16. Studies of biocompatibility of chemically etched CR-39 SSNTDs in view of their applications in alpha-particle radiobiological experiments

    International Nuclear Information System (INIS)

    Li, W.Y.; Chan, K.F.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2006-01-01

    Alpha-particle radiobiological experiments involve irradiating cells with alpha particles and require thin biocompatible materials which can record alpha-particle traversals as substrates for cell cultures. The biocompatibilities of chemically etched CR-39 solid-state nuclear track detectors (SSNTDs) using aqueous NaOH or NaOH/ehtanol are studied through the abundance and morphology of the cultured HeLa cells. The wetting properties of these etched CR-39 SSNTDs are also studied. The moderately hydrophobic CR-39 SSNTDs as well as the hydrophobic NaOH/ethanol-etched CR-39 SSNTDs are more biocompatible than the hydrophilic aqueous-NaOH-etched SSNTDs. Too small water contact angles, too large surface energy (γ s ) or the polar component γ s p do not favor the cell culture. On the other hand, the dispersive component γ s d of the surface energy and the ratio γ s p /γ s d do not seem to significantly affect the biocompatibility

  17. Angular distributions of the alpha particle production in the 7Li+144Sm system at near-barrier energies

    International Nuclear Information System (INIS)

    Carnelli, P F F; Arazi, A; Capurro, O A; Niello, J O Fernández; Heimann, D Martinez; Pacheco, A J; Cardona, M A; De Barbará, E; Figueira, J M; Hojman, D L; Martí, G V; Negri, A E

    2015-01-01

    We have studied the production of alpha particles in reactions induced by 7 Li projectiles on a 144 Sm target at bombarding energies of 18, 24 and 30 MeV over the 15°-140° angular range. The purpose of the investigation has been to determine the contribution of different mechanisms in reactions that involve weakly bound projectiles. We have included in our analysis several processes that can either directly or sequentially lead to the emission of alpha particles: complete fusion, direct transfer of 3 H, capture breakup (incomplete fusion, sequential complete fusion) and non-capture breakup. In order to distinguish alpha particles stemming from these processes it is necessary to determine the mass and charge of the reaction products and to obtain precise measurements of their energies and scattering angles over relatively wide ranges of these variables. We have done this using a detection system consisting of an ionization chamber plus three position sensitive detectors. We present results of these measurements and a preliminary interpretation based on kinematical considerations and comparisons with predictions from a statistical model. (paper)

  18. Designing experimental setup and procedures for studying alpha-particle-induced adaptive response in zebrafish embryos in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Choi, V.W.Y.; Lam, R.K.K.; Chong, E.Y.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2010-03-15

    The present work was devoted to designing the experimental setup and the associated procedures for alpha-particle-induced adaptive response in zebrafish embryos in vivo. Thin PADC films with a thickness of 16 mum were fabricated and employed as support substrates for holding dechorionated zebrafish embryos for alpha-particle irradiation from the bottom through the films. Embryos were collected within 15 min when the light photoperiod began, which were then incubated and dechorionated at 4 h post fertilization (hpf). They were then irradiated at 5 hpf by alpha particles using a planar {sup 241}Am source with an activity of 0.1151 muCi for 24 s (priming dose), and subsequently at 10 hpf using the same source for 240 s (challenging dose). The levels of apoptosis in irradiated zebrafish embryos at 24 hpf were quantified through staining with the vital dye acridine orange, followed by counting the stained cells under a florescent microscope. The results revealed the presence of the adaptive response in zebrafish embryos in vivo, and demonstrated the feasibility of the adopted experimental setup and procedures.

  19. Dependence of alpha particle track diameter on the free volume holes size using positron annihilation lifetime technique

    Energy Technology Data Exchange (ETDEWEB)

    El-Gamal, S. [Physics Department, Faculty of Education, Ain Shams University, Roxy, 11711 Cairo (Egypt); Abdalla, Ayman M., E-mail: aymanabdalla62@hotmail.com [Physics Department, Faculty of Arts and Sciences, Najran University, Najran (Saudi Arabia); Centre for Advanced Materials and Nano-Engineering, Najran University, Najran 11001 (Saudi Arabia); Abdel-Hady, E.E. [Physics Department, Faculty of Science, Minia University, BO 61519, Minia (Egypt)

    2015-09-15

    The alpha particle track diameter dependence of the free volume holes size (V{sub f}) in DAM–ADC and CR-39 nuclear track detectors was investigated using positron annihilation lifetime technique. The effect of temperature on the alpha particle track diameter and free volume were also investigated in the T-range (RT-130 °C). The obtained results revealed that the values of ortho-positronium lifetime τ{sub 3} and V{sub f} increases while I{sub 3} slightly increases as T increases for the two detectors. The values of τ{sub 3}, V{sub f} and I{sub 3} are higher in CR-39 than DAM–ADC. The interpretation of obtained results is based on the fact that increasing T leads to significant enhancement of thermal expansion of the polymer matrix and consequently V{sub f} increases. The track diameter increases as T increases. This can be explained by the fact that the increase in T increases the crystal size and V{sub f} in the polymer. A relationship between V{sub f} and the alpha particle track diameter was obtained. Moreover results of detector irradiation, along with free volume evaluation are addressed and thoroughly discussed.

  20. Probability of bystander effect induced by alpha-particles emitted by radon progeny using the analytical model of tracheobronchial tree

    International Nuclear Information System (INIS)

    Jovanovic, B.; Nikezic, D.

    2010-01-01

    Radiation-induced biological bystander effects have become a phenomenon associated with the interaction of radiation with cells. There is a need to include the influence of biological effects in the dosimetry of the human lung. With this aim, the purpose of this work is to calculate the probability of bystander effect induced by alpha-particle radiation on sensitive cells of the human lung. Probability was calculated by applying the analytical model cylinder bifurcation, which was created to simulate the geometry of the human lung with the geometric distribution of cell nuclei in the airway wall of the tracheobronchial tree. This analytical model of the human tracheobronchial tree represents the extension of the ICRP 66 model, and follows it as much as possible. Reported probabilities are calculated for various targets and alpha-particle energies. Probability of bystander effect has been calculated for alpha particles with 6 and 7.69 MeV energies, which are emitted in the 222 Rn chain. The application of these results may enhance current dose risk estimation approaches in the sense of the inclusion of the influence of the biological effects. (authors)

  1. Correlations between the alpha particles and ejectiles in the 208 MeV 14N on 93Nb reaction at three different ejectile angles

    International Nuclear Information System (INIS)

    Fukuda, T.; Ishihara, M.; Tanaka, M.; Ogata, H.; Miura, I.; Inoue, M.; Shimoda, T.; Katori, K.; Nakayama, S.

    1983-01-01

    The in plane correlations between alpha particles and various ejectiles were investigated in the reaction of 208 MeV 14 N on 93 Nb at theta/sub HI/ = +22 0 , +50 0 , and +80 0 . There were three sources of coincident alpha particles: (i) the sequential alpha decay of the excited ejectiles, (ii) the equilibrium alpha emission from the targetlike fragments, and (iii) the nonequilibrium process. Process (i) contributed mainly to the cross sections with the angular range of theta/sub α/ close to theta/sub HI/. Process (ii) contributed to the lowest part of the alpha energy spectra irrespectively of theta/sub HI/ and theta/sub α/. The remaining part was ascribed to process (iii). For this process the differential coincidence cross section of the lower energy part of the alpha particles was approximately factorized as d 4 sigma/dΩ/sub HI/dΩ/sub α/dE/sub HI/dE/sub α/ = K (d 2 sigma/dΩ/sub HI/dE/sub HI/)/sub singles/ (d 2 sigma/dΩ/sub α/dE/sub α/)/sub singles/ with Kapprox.0.4/b, whereas the higher energy part of the alpha particles emitted at the forward angles had a tendency to coincide weakly with the ejectiles emitted at the backward angles (theta/sub HI/ = +50 0 and +80 0 ) as compared to the lower energy part of the alpha particles

  2. Time-differential observation of alpha -particle perturbed angular distribution; g-factor measurements for /sup 217/Ac/sup gs/ and /sup 217/Ac/sup m/

    CERN Document Server

    Maier, K H; Grawe, H; Kluge, H

    1981-01-01

    The g-factor measurements of the ground state and an isomeric level in /sup 217/Ac using the DPAD method with alpha -decay are described. The results of gamma -ray g-factor measurements for the isomer and a tentative decay scheme produced by alpha - gamma and gamma - gamma coincidence experiments are also presented. An analysis of the alpha - particle angular distributions suggests that nuclear deformation affects the observed anisotropy. (13 refs).

  3. Search for alpha particles emitted at rest in the break-up of the 12C-α-12C molecule-like configuration

    International Nuclear Information System (INIS)

    Scheurer, J.N.; Bertault, D.; Caussanel, M.; Quebert, J.L.; Fouan, J.P.

    1978-01-01

    A yield of alpha particles emitted at rest is clearly observed in 16 O+ 12 C at several incident energies. These alpha particles are detected by two methods: i) the alpha particle is considered as a missing mass in the detection of two 12 C nuclei in coincidence; ii) the alpha particle is detected at zero degree with a velocity due to centre of mass motion. Such a yield is assigned to a linear chain formation of the type 12 C-α- 12 C and an excitation function between 40 and 65 MeV is given. The emission due to Coulomb effects is emphasized in the discussion to give the chief explanation of the coincidence results

  4. Charge-exchange diagnostic of fusion alpha particles and ICRF driven minority ions in MeV energy range in JET plasma

    International Nuclear Information System (INIS)

    Izvozchikov, A.B.; Khudoleev, A.V.; Petrov, M.P.; Petrov, S.Ya.; Kozlovskij, S.S.; Corti, S.; Gondahalekar, A.

    1991-12-01

    An important concern in alpha particle heating physics is that fusion alpha particles will be lost before giving all their energy to heat the plasma. In other words, that the radial diffusion time of the alphas may be shorter than their slowing down time in the plasma core. Therefore radially resolved measurements of density and energy spectrum of slowing-down alphas confined in the plasma are high priority diagnostic objectives. In this report application of Charge Exchange Neutral Particle Analysis on Joint European Torus will be discussed. After a description of physical principles of the method a suitable Neutral Particle Analyzer (NPA) will be described in detail and estimates of measurement performance made for different plasma heating and confinement modes in JET. (author)

  5. Scintillation response of CsI: Tl crystal under neutron, gamma, alpha particles and beta excitations

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa; Madi Filho, Tufic; Lopes, Valdir Maciel; Berretta, Jose Roberto; Cardenas, Jose Patricio Nahuel, E-mail: macoper@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Among the converters of X and gamma radiation in light photons, known as scintillators, the one which is the most efficient emits photons with a wavelength near 400 nm. Particularly, among them, the cesium iodine doped with thallium (CsI:Tl) crystal is that which matches better between the light emission spectrum (peak at 540 nm) and the quantum sensitivity curve of the photodiodes and CCD (Charge Coupled Device). This explains the renewed interest in using this crystal as scintillator. Although the CsI:Tl crystal is commercially available, its local development would give the possibility to obtain it in different geometric configurations and coupling. Moreover, there is a special interest in studying new conditions that will alter the properties of this crystal in order to achieve a optimal level of its functional characteristics. Having an efficient national scintillator with low cost is a strategic opportunity to study the response of a detector applied to different types of radiation. The crystal of cesium iodide activated with thallium (CsI:Tl) has a high gamma detection efficiency per unit volume. In this paper, the CsI:Tl crystal, grown by the vertical Bridgman technique in evacuated silica ampoules and with the purpose of use as radiation detectors, is described. To evaluate the scintillator, measures of the thallium distribution in the crystal volume were taken, with overall efficiency score. The scintillator response was studied through gamma radiation from sources of {sup 137}Cs, {sup 60}Co, {sup 22}Na, {sup 54}Mn, {sup 131}I and {sup 99m}Tc; the beta radiation from source of {sup 90}Sr/{sup 90}Y, alpha particles from {sup 241}Am source and the scintillator response to neutrons from Am/Be source. The energetic resolution for {sup 137}Cs gamma rays (662 keV) was 10%. The results showed the validity of using the CsI:Tl crystal developed in our laboratory, in many applications in the area of radiation detectors. (author)

  6. NM Gross Receipts Baseline

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This layer represents boundaries for New Mexico's gross receipts tax districts as identified on the "Gross Receipts Tax Rate Schedule" published by the Taxation and...

  7. Overview of the first workshop on alpha particle physics in TFTR

    International Nuclear Information System (INIS)

    Zweben, S.J.; Biglari, H.

    1991-07-01

    The ''First Workshop on Alpha Physics in TFTR'' was held at the Princeton Plasma Physics Lab March 28--29, 1991. The motivation for this meeting was to clarify and strengthen the TFTR alpha physics program, and to increase the involvement of the fusion community outside PPPL in the TFTR D-T experiments. Therefore the meeting was sharply focused on alpha physics relevant to the upcoming TFTR D-T simulation, and was asked to devote half of his talk to specific TFTR issues. The Workshop consisted of 27 talks on: (1) experimental possibilities; (2) theoretical possibilities; (3) diagnostic possibilities; (4) relevance for future machines; and (5) discussion/summary session. This summary contains a brief sampling of the new results and ideas brought out by these talks, followed by two more general overviews of the status of experiment and theory

  8. Gross National Happiness

    DEFF Research Database (Denmark)

    Giri, Krishna Prasad; Kjær-Rasmussen, Lone Krogh

    This paper investigates practices related to the ideology of infusing Gross National Happiness (GNH) into school curriculum, the effectiveness of the meditation and mind training and the implication of GNH for school environment. It also explores how GNH ambience has been managed and practiced...... of Gross National Happiness and Educating for Gross National happiness....

  9. Response of Ni/4H-SiC Schottky barrier diodes to alpha-particle irradiation at different fluences

    Energy Technology Data Exchange (ETDEWEB)

    Omotoso, E., E-mail: ezekiel.omotoso@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Departments of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Meyer, W.E.; Auret, F.D.; Diale, M.; Ngoepe, P.N.M. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa)

    2016-01-01

    Irradiation experiments have been carried out on 1.9×10{sup 16} cm{sup −3} nitrogen-doped 4H-SiC at room temperature using 5.4 MeV alpha-particle irradiation over a fluence ranges from 2.6×10{sup 10} to 9.2×10{sup 11} cm{sup −2}. Current–voltage (I–V), capacitance–voltage (C–V) and deep level transient spectroscopy (DLTS) measurements have been carried out to study the change in characteristics of the devices and free carrier removal rate due to alpha-particle irradiation, respectively. As radiation fluence increases, the ideality factors increased from 1.20 to 1.85 but the Schottky barrier height (SBH{sub I–V}) decreased from 1.47 to 1.34 eV. Free carrier concentration, N{sub d} decreased with increasing fluence from 1.7×10{sup 16} to 1.1×10{sup 16} cm{sup −2} at approximately 0.70 μm depth. The reduction in N{sub d} shows that defects were induced during the irradiation and have effect on compensating the free carrier. The free carrier removal rate was estimated to be 6480±70 cm{sup −1}. Alpha-particle irradiation introduced two electron traps (E{sub 0.39} and E{sub 0.62}), with activation energies of 0.39±0.03 eV and 0.62±0.08 eV, respectively. The E{sub 0.39} as attribute related to silicon or carbon vacancy, while the E{sub 0.62} has the attribute of Z{sub 1}/Z{sub 2}.

  10. Final Report (1994 to 1996) Diagnostic of the Spatial and Velocity Distribution of Alpha Particles in Tokamak Fusion Reactor using Beat-wave Generated Lower Hybrid Wave

    International Nuclear Information System (INIS)

    Hwang, D.Q.; Horton, R.D.; Evans, R.W.

    1999-01-01

    The alpha particles in a fusion reactor play a key role in the sustaining the fusion reaction. It is the heating provided by the alpha particles that help a fusion reactor operating in the ignition regime. It is, therefore, essential to understand the behavior of the alpha population both in real space and velocity space in order to design the optimal confinement device for fusion application. Moreover, the alphas represent a strong source of free energy that may generate plasma instabilities. Theoretical studies has identified the Toroidal Alfven Eigenmode (TAE) as an instability that can be excited by the alpha population in a toroidal device. Since the alpha has an energy of 3.5 MeV, a good confinement device will retain it in the interior of the plasma. Therefore, alpha measurement system need to probe the interior of a high density plasma. Due to the conducting nature of a plasma, wave with frequencies below the plasma frequency can not penetrate into the interior of the plasma where the alphas reside. This project uses a wave that can interact with the perpendicular motion of the alphas to probe its characteristics. However, this wave (the lower hybrid wave) is below the plasma frequency and can not be directly launched from the plasma edge. This project was designed to non-linearly excite the lower hybrid in the interior of a magnetized plasma and measure its interaction with a fast ion population

  11. Gamma-H2AX foci in cells exposed to a mixed beam of X-rays and alpha particles

    Science.gov (United States)

    2012-01-01

    Background Little is known about the cellular effects of exposure to mixed beams of high and low linear energy transfer radiation. So far, the effects of combined exposures have mainly been assessed with clonogenic survival or cytogenetic methods, and the results are contradictory. The gamma-H2AX assay has up to now not been applied in this context, and it is a promising tool for investigating the early cellular response to mixed beam irradiation. Purpose To determine the dose response and repair kinetics of gamma-H2AX ionizing radiation-induced foci in VH10 human fibroblasts exposed to mixed beams of 241Am alpha particles and X-rays. Results VH10 human fibroblasts were irradiated with each radiation type individually or both in combination at 37°C. Foci were scored for repair kinetics 0.5, 1, 3 and 24 h after irradiation (one dose per irradiation type), and for dose response at the 1 h time point. The dose response effect of mixed beam was additive, and the relative biological effectiveness for alpha particles (as compared to X-rays) was of 0.76 ± 0.52 for the total number of foci, and 2.54 ± 1.11 for large foci. The repair kinetics for total number of foci in cells exposed to mixed beam irradiation was intermediate to that of cells exposed to alpha particles and X-rays. However, for mixed beam-irradiated cells the frequency and area of large foci were initially lower than predicted and increased during the first 3 hours of repair (while the predicted number and area did not). Conclusions The repair kinetics of large foci after mixed beam exposure was significantly different from predicted based on the effect of the single dose components. The formation of large foci was delayed and they did not reach their maximum area until 1 h after irradiation. We hypothesize that the presence of low X-ray-induced damage engages the DNA repair machinery leading to a delayed DNA damage response to the more complex DNA damage induced by alpha particles. PMID:23121736

  12. A New Interpretation of Alpha-particle-driven Instabilities in Deuterium-Tritium Experiments on the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    R. Nazikian; G.J. Kramer; C.Z. Cheng; N.N. Gorelenkov; H.L. Berk; S.E. Sharapov

    2003-01-01

    The original description of alpha-particle-driven instabilities in the Tokamak Fusion Test Reactor (TFTR) in terms of Toroidal Alfvin Eigenmodes (TAEs) remained inconsistent with three fundamental characteristics of the observations: (i) the variation of the mode frequency with toroidal mode number, (ii) the chirping of the mode frequency for a given toroidal mode number, and (iii) the anti-ballooning density perturbation of the modes. It is now shown that these characteristics can be explained by observing that cylindrical-like modes can exist in the weak magnetic shear region of the plasma that then make a transition to TAEs as the central safety factor decreases in time

  13. Attempt of analysis of the elastic scattering of 44 MeV alpha particles using a phase shift parameterization

    International Nuclear Information System (INIS)

    Papiau, Anne-Marie

    1966-01-01

    In order to ease the resolution of the problem of interaction of an alpha particle with a nucleus, and determine simpler hypotheses which enable the analysis of experimental results, this research thesis reports the use of a parameterization of phase shifts to reduce ambiguities and the number of parameters. After general remarks, a description of the Hamiltonian and a formulation of phase shifts, the author presents experimental data and the analytical method. Analysis is then performed for two-, three-, four- or five-parameter formulations. Efficient cross sections are then studied

  14. Low-energy elastic-scattering of alpha particles from [sup 34]S, [sup 50]Cr and [sup 62]Ni

    Energy Technology Data Exchange (ETDEWEB)

    Bredbacka, AA. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Brenner, M. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Kaellman, K.-M. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Manngaard, P. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Mate, Z. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary)); Szilagyi, S. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary)); Zolnai, L. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary))

    1994-07-11

    Angular distributions of elastically scattered alpha particles were measured for the [sup 34]S, [sup 50]Cr and [sup 62]Ni target nuclei in the energy range 12.8-20.0 MeV. The experimental data were analysed using the phenomenological optical model with the Saxon-Woods form factor; in the case of [sup 34]S the squared Saxon-Woods form factor was also applied. Phenomena such as the anomalous energy dependence of the potential near the Coulomb barrier, the discrete ambiguity problem, the low-mass and low-energy limit of applicability of the optical model are discussed using the real volume integral values obtained. ((orig.))

  15. A Comparitive Assessement of Cytokine Expression in Human-Derived Cell Lines Exposed to Alpha Particles and X-Rays

    Directory of Open Access Journals (Sweden)

    Vinita Chauhan

    2012-01-01

    Full Text Available Alpha- (α- particle radiation exposure has been linked to the development of lung cancer and has been identified as a radiation type likely to be employed in radiological dispersal devices. Currently, there exists a knowledge gap concerning cytokine modulations associated with exposure to α-particles. Bio-plex technology was employed to investigate changes in proinflammatory cytokines in two human-derived cell lines. Cells were irradiated at a dose of 1.5 Gy to either α-particles or X-rays at equivalent dose rates. The two cell lines exhibited a unique pattern of cytokine expression and the response varied with radiation type. Of the 27 cytokines assessed, only vascular endothelin growth factor (VEGF was observed to be modulated in both cell lines solely after α-particle exposure, and the expression of VEGF was shown to be dose responsive. These results suggest that certain proinflammatory cytokines may be involved in the biological effects related to α- particle exposure and the responses are cell type and radiation type specific.

  16. Determination of the area density and composition of alloy film using dual alpha particle energy loss

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaojun, E-mail: maxj802@163.com [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Bo; Gao, Dangzhong [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Xu, Jiayun [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Tang, Yongjian [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2017-02-01

    A novel method based on dual α-particles energy loss (DAEL) is proposed for measuring the area density and composition of binary alloy films. In order to obtain a dual-energy α-particles source, an ingenious design that utilizes the transmitted α-particles traveling the thin film as a new α-particles source is presented. Using the DAEL technique, the area density and composition of Au/Cu film are determined accurately with an uncertainty of better than 10%. Finally, some measures for improving the combined uncertainty are discussed.

  17. Discrimination of alpha particles in CdZnTe detectors with coplanar grid for the COBRA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rebber, Henning [Universitaet Hamburg, Institut fuer Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg (Germany); Collaboration: COBRA-Collaboration

    2016-07-01

    The aim of the COBRA experiment is the search for neutrinoless double beta decay using CdZnTe semiconductor detectors. A background rate in the order of 10{sup -3} counts per keV, kg and year is intended in order to be sensitive to a half-life larger than 10{sup 26} years. Measurements from a demonstrator setup and Monte Carlo simulations indicate that a large background component is due to alpha particles. These generate charge clouds of only few μm in diameter in the detector, leading to characteristic pulse features. Parameter-based cut criteria were developed to discriminate alpha events by means of their pulse shapes. The cuts were tested on data from alpha and beta irradiation of a (1 x 1 x 1) cm{sup 3} CdZnTe detector with coplanar grid. The pulse shapes of all event signals were read out by FADCs with a sampling rate of 100 MHz. The signals were reproduced by a detector simulation which hence was used to study the cuts for energies up to 3 MeV and different detector regions.

  18. Transcriptional Response of Human Cells to Microbeam Irradiation with 2.1 MeV Alpha Particles

    Science.gov (United States)

    Hellweg, C. E.; Bogner, S.; Spitta, L.; Arenz, A.; Baumstark-Khan, C.; Greif, K. D.; Giesen, U.

    Within the next decades an increasing number of human beings in space will be simultaneously exposed to different stimuli especially microgravity and radiation To assess the risks for humans during long-duration space missions the complex interplay of these parameters at the cellular level must be understood Cellular stress protection responses lead to increased transcription of several genes via modulation of transcription factors Activation of the Nuclear Factor kappa B NF- kappa B pathway as a possible anti-apoptotic route represents such an important cellular stress response A screening assay for detection of NF- kappa B-dependent gene activation using the destabilized variant of Enhanced Green Fluorescent Protein d2EGFP as reporter protein had been developed It consists of Human Embryonic Kidney HEK 293 Cells stably transfected with a receptor-reporter-construct carrying d2EGFP under the control of a NF- kappa B response element Clones positive for Tumor Necrosis Factor alpha TNF- alpha inducible d2EGFP expression were selected as cellular reporters Irradiation was performed either with X-rays 150 kV 19 mA at DLR Cologne or with 2 1 MeV alpha particles LET sim 160 keV mu m at PTB Braunschweig After irradiation the following biological endpoints were determined i cell survival via the colony forming ability test ii time-dependent activation of NF- kappa B dependent d2EGFP gene expression using flow cytometry iii quantitative RT-PCR

  19. Investigation of double strand breaks induced by alpha particle irradiation using C.N.B.G. microbeam in human keratinocytes

    International Nuclear Information System (INIS)

    Pouthier, Th.

    2006-12-01

    To understand the mechanisms of interaction of ionizing radiation with living tissues exposed to low and protracted doses remains a major issue for risk evaluation. The response cannot be found in epidemiological studies because the only available data concern accidental exposures to high doses of radiation. The natural exposure represents the main source of exposure in the daily life, just before the medical sources (radiology, radiotherapy). In addition, this kind of exposure is very difficult to reproduce in vitro by irradiating cell lines. The method per preference is based on random irradiation of cell populations. The mean number of particles having traversed cells is then calculated on the basis of Poisson statistics. In addition to inevitable multiple impacts, the numerous potential intracellular targets (nuclei, cytoplasm), the indirect effects induced by the impact of particles on neighbouring cells or simply the extracellular targets, constitute phenomena that make more complex the interpretation of experimental data. A charged particle microbeam was developed at C.E.N.B.G. to perform the targeted irradiation of individual cells with a targeting precision of a few microns. It is possible to deliver a counted number of alpha particles down to the ultimate dose of one alpha per cell, to target predetermined cells and then to observe the response of the neighbouring cells. This facility has been validated during this work on human keratinocyte cells expressing a recombinant nuclear fluorescent protein (histone H2B-GFP). The combination of ion micro-beams with confocal microscopy and numeric quantitative analysis allowed the measurement of DNA double strand breaks via the phosphorylation of the histone H2A.X in individual cells. The mechanisms of DNA reparation and apoptosis induction were also in the scope of those studies. The experimental results obtained during this thesis validate the methodology we have developed by demonstrating the targeting

  20. Unified semimicroscopic approach scattering of low energy protons and alpha-particles by nuclei

    International Nuclear Information System (INIS)

    Dao Tien Khoa; Kukhtina, I.N.; Knyaz'kov, O.M.; Feofilov, G.A.

    1988-01-01

    The unified approach has been developed to the description of the interaction of low energy nucleons and α-particles with nuclei. The analysis of elastic and inelastic scattering of 25.05 MeV protons and 104 MeV α-particles from 90 Zr is made. The differences in deformations of neutron and proton density distributions for 90 Zr nucleus are extracted. The energy dependence of the obtained α-particle - nucleus semimicroscopic potential is investigated, including the energy dependence for the geometry of the potential. The feaures of angular distributions of elastic α-particle scattering and the role of nucleon-nucleon correlations are analysed as a function of α-particle energy

  1. Alpha-particle effects on high-n instabilities in tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.

    1988-06-01

    Hot α-particles and thermalized helium ash particles in tokamaks can have significant effects on high toroidal mode number instabilities such as the trapped-electron drift mode and the kinetically calculated magnetohydrodynamic ballooning mode. In particular, the effects can be stabilizing, destabilizing, or negligible, depending on the parameters involved. In high-temperature tokamaks capable of producing significant numbers of hot α-particles, the predominant interaction of the mode with the α-particles is through resonances of various sorts. In turn, the modes can cause significant anomalous transport of the α-particles and the helium ash. Here, results of comprehensive linear eigenfrequency-eigenfunction calculations are presented for relevant realistic cases to show these effects. 24 refs., 12 figs., 6 tabs

  2. Calculations on precompound reactions with alpha particles, A(α,α')X, at incident energies around 500 MeV

    International Nuclear Information System (INIS)

    Rittershausen, W.

    1987-01-01

    The model of Chiang et al. (1980) for nucleon induced precompound reactions, a generalization of the Glauber theory to lower energetical processes, was extended to heavier projectiles the elementary differential cross section of which may furthermore (at fixed incident energy) depend on the momentum transfer. The so modified model was applied to reactions of the type A(α,α')X at an incident energy of about 100 MeV/nucleon, excitation energies of the nucleus in the range 6 to 60 MeV, and for scattering angles from 3 to 6 0 . Thereby the Glauber coefficients were determined by means of the optical potentials known for the treated experiments. Local nucleon momentum distributions in the target nucleus were taken from calculations of Durand et al. (1982). The momentum distributions of the alpha particles after the first α-N collision were both for normalously and for homogeneously distributed nucleon momenta calculated analytically. The distributions after the second collision were determined by folding. For the control of these results and for the eventual calculation of the distributions after more than two collisions a Monte Carlo routine was written. The additional deviation of the alpha particles in real-valued potentials of the target nucleus were regarded. The results in which no free parameter occurs agree quite well in the shape with measured data. In one case it is also valid for the absolute quantities. (orig.) [de

  3. Fabrication of substrates with curvature for cell cultivation by alpha-particle irradiation and chemical etching of PADC films

    International Nuclear Information System (INIS)

    Ng, C.K.M.; Tjhin, V.T.; Lin, A.C.C.; Cheng, J.P.; Cheng, S.H.; Yu, K.N.

    2012-01-01

    In the present paper, we developed a microfabrication technology to generate cell-culture substrates with identical chemistry and well-defined curvature. Micrometer-sized pits with curved surfaces were created on a two-dimensional surface of a polymer known as polyallyldiglycol carbonate (PADC). A PADC film was first irradiated by alpha particles and then chemically etched under specific conditions to generate pits with well-defined curvature at the incident positions of the alpha particles. The surface with these pits was employed as a model system for studying the effects of substrate curvature on cell behavior. As an application, the present work studied mechanosensing of substrate curvature by epithelial cells (HeLa cells) through regulation of microtubule (MT) dynamics. We used end-binding protein 3–green fluorescent protein (EB3–GFP) as a marker of MT growth to show that epithelial cells having migrated into the pits with curved surfaces had significantly smaller MT growth speeds than those having stayed on flat surfaces without the pits.

  4. The alpha-particle irradiator set up at the ISS for radiobiological studies on targeted and non-targeted effects

    International Nuclear Information System (INIS)

    Esposito, G.; Antonelli, F.; Belli, M.; Campa, A.; Simone, G.; Sorrentino, E.; Tabocchini, M.A.

    2008-01-01

    In this paper we describe the alpha-particle irradiator that has been set up at the Istituto Superiore di Sanita (ISS) for controlled exposure of cultured mammalian cells. It can be equipped with two different sources, namely 2'4'4'Cm and 2'4'1'Am, allowing irradiation at different dose-rates (typically 1-100 mGy/min). The irradiator has dimensions small enough to be inserted into a standard cell culture incubator to perform irradiation of cultured cells in physiological conditions. The dose uniformity is such that the variations in the irradiation area are less than ± 12% of the average dose value on different irradiation areas up to ∼ 25 cm'2. Moreover, in the framework of the FP6 Euratom Integrated Project Non-targeted effects of ionizing radiation (NOTE), Petri dishes were realized for housing permeable membrane insert(s) to be used in co-culture experiments. Aluminium shields were also realized for half shield irradiation experiments. The alpha-particle irradiator of the ISS has been successfully used for studying DNA damage, namely double strand breaks (DSB, as measured by the γ-H2AX assay), in directly hit and in bystander primary human fibroblasts [it

  5. Nitric oxide mediated DNA double strand breaks induced in proliferating bystander cells after {alpha}-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chen Shaopeng [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2010-02-03

    Low-dose {alpha}-particle exposures comprise 55% of the environmental dose to the human population and have been shown to induce bystander responses. Previous studies showed that bystander effect could induce stimulated cell growth or genotoxicity, such as excessive DNA double strand breaks (DSBs), micronuclei (MN), mutation and decreased cell viability, in the bystander cell population. In the present study, the stimulated cell growth, detected with flow cytometry (FCM), and the increased MN and DSB, detected with p53 binding protein 1 (53BP1) immunofluorescence, were observed simultaneously in the bystander cell population, which were co-cultured with cells irradiated by low-dose {alpha}-particles (1-10 cGy) in a mixed system. Further studies indicated that nitric oxide (NO) and transforming growth factor {beta}1 (TGF-{beta}1) played very important roles in mediating cell proliferation and inducing MN and DSB in the bystander population through treatments with NO scavenger and TGF-{beta}1 antibody. Low-concentrations of NO, generated by spermidine, were proved to induce cell proliferation, DSB and MN simultaneously. The proliferation or shortened cell cycle in bystander cells gave them insufficient time to repair DSBs. The increased cell division might increase the probability of carcinogenesis in bystander cells since cell proliferation increased the probability of mutation from the mis-repaired or un-repaired DSBs.

  6. Radiation quality and effective dose equivalent of alpha particles from radon decay products indoors: uncertainties in risk estimation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Affan, I.A. (Velindre Hospital, Whitchurch, Cardiff (United Kingdom))

    1994-01-01

    In order to make a better estimate of cancer risk due to radon the radiation quality of alpha particles emitted from the element and its daughters has been re-assessed. In particular, uncertainties in all components involved in the calculations of the effective dose E, have been investigated. This has been done in the light of the recent draft report of the ICRU on quantities and units for use in radiation protection (Allisy et al (1991) ICRU NEWS 2). On the assumption of an indoor radon concentration of 30 Bq.m[sup -3], microdose spectra have been calculated for alpha particles hitting lung cells at different depths. Then the mean quality factor Q-bar in the lung, dose equivalent H[sub T] to the lung and the effective dose have been calculated. A comparison between lung cancer risk from radon and that arising from diagnostic X rays to the chest is made. A suggestion to make the lung weighting factor w[sub T] a function of the fraction of lung cells hit is discussed. (Author).

  7. Study of substrate topographical effects on epithelial cell behavior using etched alpha-particle tracks on PADC films

    International Nuclear Information System (INIS)

    Ng, C.K.M.; Poon, W.L.; Li, W.Y.; Cheung, T.; Cheng, S.H.; Yu, K.N.

    2008-01-01

    Micrometer-size pits on the surface of a polymer (polyallyldiglycol carbonate or PADC) substrate created by alpha-particle irradiation and subsequent chemical etching were used to study the topographical effects alone on cell behavior. Vinculin, the cell adhesion and membrane protrusion protein, was used as an indicator of cytoskeletonal reorganization on the substrate and localization of vinculin was used to demonstrate the presence of focal adhesions. In our experiments, vinculin expressed in epithelial HeLa cells cultured on PADC films with track-etch pits, but not in cells cultured on the raw or chemically etched blank films. In other words, vinculin expression was induced by the topography of track-etch pits, while etching of the substrate alone (without alpha-particle irradiation) did not cause up-regulation of vinculin protein expression. HeLa cells cultured on PADC films with track-etch pits also showed changes in cell proliferation, cell area and cell circularity, and were largely contained by the pits. In other words, the cell membrane edges tended to be in contact with the pits. By comparing the correlation between the positions of HeLa cells and the pits, and that between the positions of cells and computer-simulated pits, the tendency for membrane edges of HeLa cells to be in contact with the pits was recognized. This could be explained by inhibition of membrane protrusion at the pits. In conclusion, substrate track-etch pits were an important determinant of epithelial cell behaviors

  8. Tetraethyl ammonium hydroxide (TEAH) as etchant of CR-39 for the determination of fluence of alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Joshirao, Pranav M.; Vyas, Chirag K.; Eappen, K.P. [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Shin, Jae Won [Department of Physics, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Hong, Seung-Woo [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Department of Physics, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Manchanda, Vijay K., E-mail: vkm49@skku.edu [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440746 (Korea, Republic of)

    2014-04-01

    Highlights: • Etching time of CR-39 with TEAH–NaOH mixture (at 80 °C) is less than 20 min. • Etched products enhance etching rate. • V{sub B} and V{sub T} values increase exponentially with temperature. • Activation energy of bulk etching and track etching were determined as 0.87 ± 0.02 eV. - Abstract: Choice of chemical etchant and temperature are pivotal to the successful employment of organic/polymeric solid state nuclear track detectors for determining the fluence of charged particles like protons, alpha and other heavy ions. Poly(diethyleneglycol-bis-(allylcarbonate)) (CR-39) is one of the most sensitive detectors for monitoring the alpha particles but suffers from the drawback of long etching period. An attempt has been made in the present work to investigate a mixture, 20% (v/v) tetraethylammonium hydroxide (40%) – 80% NaOH (6 M) (TEAH–NaOH) at varying temperature as an alternate etchant. It was found that bulk/track etch rate increased and as a consequence etching time decreased significantly (about 10 times) when the mixture was used at 80 °C. Mechanistically, improved efficiency of TEAH–NaOH was attributed to its larger organophilicity and lower etching activation energy as compared to NaOH.

  9. High-temperature performance of gallium-nitride-based pin alpha-particle detectors grown on sapphire substrates

    Science.gov (United States)

    Zhu, Zhifu; Zhang, Heqiu; Liang, Hongwei; Tang, Bin; Peng, Xincun; Liu, Jianxun; Yang, Chao; Xia, Xiaochuan; Tao, Pengcheng; Shen, Rensheng; Zou, Jijun; Du, Guotong

    2018-06-01

    The temperature-dependent radiation-detection performance of an alpha-particle detector that was based on a gallium-nitride (GaN)-based pin structure was studied from 290 K to 450 K. Current-voltage-temperature measurements (I-V-T) of the reverse bias show the exponential dependence of leakage currents on the voltage and temperature. The current transport mechanism of the GaN-based pin diode from the reverse bias I-V fitting was analyzed. The temperature-dependent pulse-height spectra of the detectors were studied using an 241 Am alpha-particle source at a reverse bias of 10 V, and the peak positions shifted from 534 keV at 290 K to 490 keV at 450 K. The variation of full width at half maximum (FWHM) from 282 keV at 290 K to 292 keV at 450 K is almost negligible. The GaN-based pin detectors are highly promising for high-temperature environments up to 450 K.

  10. Alpha-particle confinement and helium ash accumulation in stellarator reactors

    International Nuclear Information System (INIS)

    Ho, D.D.-M.; Kulsrud, R.M.

    1986-01-01

    The effect of local magnetic wells produced by the external helical windings of a stellarator reactor on α-particle confinement is investigated by using the Fokker-Planck equation. It is found that α-particles can deposit most of their energy into the background plasma before they scatter into the trapped region in velocity space and are lost. An estimate is made on the steady-state, low energy (thermal) α-particle concentration. The result shows that this concentration will be less than a few per cent of the background plasma density. (author)

  11. The interaction of energetic alpha-particles with intense lower hybrid waves

    International Nuclear Information System (INIS)

    Fisch, N.J.; Rax, J.M.

    1992-06-01

    Lower hybrid waves are a demonstrated, continuous means of driving toroidal current in a tokamak. When these waves propagate in a tokamak fusion reactor, in which there are energetic α- particles, there are conditions under which the α-particles do not appreciably damp, and may even amplify, the wave, thereby enhancing the current-drive effect. Waves traveling in one poloidal direction, in addition to being directed in one toroidal direction, are shown to be the most efficient drivers of current in the presence of the energetic α-particles

  12. Alpha-particle energy spectra measured at forward angles in heavy-ion-induced reactions

    International Nuclear Information System (INIS)

    Borcea, C.; Cierlic, E.; Kalpakchieva, R.; Oganessian, Yu.Ts.; Penionzhkevich, Yu.E.

    1980-01-01

    Energy spectra have been measured for α-particles emitted in the bombardment of 159 Tb, 181 Ta, 197 Au, and 232 Th nuclei by 20 Ne, 22 Ne, and 40 Ar projectiles. The reaction products emitted in the angular range (0+-2)deg relative to the beam direction were analyzed using a magnetic spectrometer and detected by means of a semiconductor ΔE-E telescope. It was found that in all cases the experimentally measured maximum α-particle energy almost amounts to the maximum possible value calculated from the reaction energy balance for a two-body exit channel. A correlation was found between the measured absolute cross section in different target-projectile combinations and the α-particle binding energy in the target nuclei. On the basis of the obtained results a conclusion has been drawn that the α-particles are emitted in the early stage of the reaction

  13. Correction for the absorption of plutonium alpha particles in filter paper used for dust sampling

    Energy Technology Data Exchange (ETDEWEB)

    Simons, J G

    1956-01-01

    This sample of air-borne dust collected on a filter paper when laboratory air is monitored for plutonium with the 1195 portable dust sampling unit may be regarded, for counting purposes, as a thick source with a non-uniform distribution of alpha-active plutonium. Experiments have been carried out to determine a correction factor to be applied to the observed count on the filter paper sample to correct for internal absorption in the paper and on the dust layer. From the results obtained it is recommended that a correction factor of 2 be used.

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  15. Alpha-particle-induced soft errors in high speed bipolar RAM

    International Nuclear Information System (INIS)

    Mitsusada, Kazumichi; Kato, Yukio; Yamaguchi, Kunihiko; Inadachi, Masaaki

    1980-01-01

    As bipolar RAM (Random Access Memory) has been improved to a fast acting and highly integrated device, the problems negligible in the past have become the ones that can not be ignored. The problem of a-particles emitted from the radioactive substances in semiconductor package materials should be specifically noticed, which cause soft errors. The authors have produced experimentally the special 1 kbit bipolar RAM to investigate its soft errors. The package used was the standard 16 pin dual in-line type, with which the practical system mounting test and a-particle irradiation test have been performed. The results showed the occurrence of soft errors at the average rate of about 1 bit/700 device hour. It is concluded that the cause was due to the a-particles emitted from the package materials, and at the same time, it was found that the rate of soft error occurrence was able to be greatly reduced by shielding a-particles. The error rate significantly increased with the decrease of the stand-by current of memory cells and with the accumulated charge determined by time constant. The mechanism of soft error was also investigated, for which an approximate model to estimate the error rate by means of the effective noise charge due to a-particles and of the amount of reversible charges of memory cells is shown to compare it with the experimental results. (Wakatsuki, Y.)

  16. K-shell X-ray production cross sections of Ni induced by protons, alpha-particles, and He{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Bertol, A.P.L. [Programa de Pós-graduação em Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Hinrichs, R. [Programa de Pós-graduação em Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Vasconcellos, M.A.Z., E-mail: marcos@if.ufrgs.br [Programa de Pós-graduação em Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    2015-11-15

    The proton, alpha-particle, and He{sup +} induced X-ray emissions of Ni were measured on mono-elemental thin films in order to obtain the K-shell X-ray production cross section in the energy range of 0.7–2.0 MeV for protons, 4.0–6.5 MeV for alpha-particles, and 3.0–4.0 MeV for He{sup +}. The proton-induced X-ray production cross section for Ni agreed well with the theoretical values, endorsing the quality of the measurements. The X-ray production cross section induced with alpha-particles is in good agreement with ECPSSR theory in the complete range of energies, while for He{sup +} that quantity is systematically below. K{sub β}/K{sub α} ratios were evaluated and compared with experimental and theoretical values.

  17. Some general features of alpha-particle pick-up reactions

    International Nuclear Information System (INIS)

    Becchetti, F.D.; Jaenecke, J.

    1982-01-01

    The general features of single- and multi-α transfer reactions are discussed. While there are numerous difficulties in extracting α-particle ''spectroscopic'' factors, the reduced α-widths extracted appear to be meaningful. These can be related, in an absolute fashion, to α-decay widths (or α-decay lifetimes). Simpler theories describing α-particle transfer reactions are needed and should be formulated in terms of α-widths, i.e. α-particle densities in the nuclear periphery. These are the quantities measured in most experiments. IBA and SU 3 models appear to be most relevant and should be extended to α-transfer reactions for heavy nuclei. (Auth.)

  18. Distance distribution of bystander effects in alpha-particle irradiated cell populations using a CR-39-based culture dish

    International Nuclear Information System (INIS)

    Gaillard, S.; Pusset, D.; Toledo, S.M. de; Azzam, E.I.; Fromm, M.

    2008-01-01

    Propagation of induced biological effects from irradiated to non-irradiated cells is known to occur in cell cultures exposed to low fluences of charged particles. These bystander effects are currently investigated using microbeam or non-microbeam (broad beams) irradiation techniques. Identification of the targeted and non-targeted bystander cells is critical to our understanding of mechanisms underlying such effects. We developed a novel cell culture dish where the base consists of a thin CR-39 sheet grafted on a thin polyethylene terephthalate (PET) foil. The validity of this device in identifying not only irradiated cells, but also the cellular compartment traversed by the particle track is described. We have optimized track etch parameters that do not interfere with measurement of induced biological endpoints under normal incident irradiation. Thus the culture dishes can be used to determine distance distributions for the propagation of induced biological effects from a hit cell to bystander cells. We describe the computer code developed to determine the distance distributions of propagated biological stress responses in normal human fibroblast cells exposed to very low fluences of alpha particles

  19. Genomic Profiling of a Human Leukemic Monocytic Cell-Line (THP-1 Exposed to Alpha Particle Radiation

    Directory of Open Access Journals (Sweden)

    Vinita Chauhan

    2012-01-01

    Full Text Available This study examined alpha (α- particle radiation effects on global changes in gene expression in human leukemic monocytic cells (THP-1 for the purposes of mining for candidate biomarkers that could be used for the development of a biological assessment tool. THP-1 cells were exposed to α-particle radiation at a dose range of 0 to 1.5 Gy. Twenty-four hours and three days after exposure gene expression was monitored using microarray technology. A total of 16 genes were dose responsive and classified as early onset due to their expression 24 h after exposure. Forty-eight transcripts were dose responsive and classified as late-onset as they were expressed 72 h after exposure. Among these genes, 6 genes were time and dose responsive and validated further using alternate technology. These transcripts were upregulated and associated with biological processes related to immune function, organelle stability and cell signalling/communication. This panel of genes merits further validation to determine if they are strong candidate biomarkers indicative of α-particle exposure.

  20. Basic principles approach for studying nonlinear Alfven wave-alpha particle dynamics

    International Nuclear Information System (INIS)

    Berk, H.L.; Breizman, B.N.; Pekker, M.

    1994-01-01

    An analytical model and a numerical procedure are presented which give a kinetic nonlinear description of the Alfven-wave instabilities driven by the source of energetic particles in a plasma. The steady-state and bursting nonlinear scenarios predicted by the analytical theory are verified in the test numerical simulation of the bump-on-tail instability. A mathematical similarity between the bump-on-tail problem for plasma waves and the Alfven wave problem gives a guideline for the interpretation of the bursts in the wave energy and fast particle losses observed in the tokamak experiments with neutral beam injection

  1. Tamper temperature and compression from simultaneous proton and alpha-particle measurements in laser fusion experiments

    International Nuclear Information System (INIS)

    Cover, R.A.; Kubis, J.J.; Mayer, F.J.; Slater, D.C.

    1978-01-01

    The energy loss per unit path length for a charged particle incident on a spatially uniform isothermal Maxwellian plasma is a function of the temperature and density of the medium. Within this model the temperature and compression rhoΔr of the tamper of a laser-driven microshell target can be accurately determined, in the absence of electrostatic acceleration, by the simultaneous measurement of the energy loss from 3.52-MeV α particles from D-T reactions and 3.02-MeV protons from D-D reactions

  2. Portable instrument for selectively detecting alpha-particles derived from radon

    International Nuclear Information System (INIS)

    Chapuis, A.M.; DaJlevic, D.

    1975-01-01

    A portable instrument of the pocket type designed primarily for monitoring atmospheric contamination in uranium mines by selectively detecting the α-particles emitted simultaneously by the daughter products of radon, namely radium A and radium C' is described. The instrument comprises in combination a tube containing a suction fan for drawing external air through a filter which retains the α-emitting aerosols, a detector in which the α-particles corresponding to the respective energies of the α-emissions of radium A and of radium C' are detected separately, and two collimators placed between the filter and the detector

  3. The use of CH3OH additive to NaOH for etching alpha particle tracks in a CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    Ashry, A.H.; Abdalla, A.M.; Rammah, Y.S.; Eisa, M.; Ashraf, O.

    2014-01-01

    Fast detection of alpha particles in CR-39 detectors was investigated using a new chemical etchant. 252 Cf and 241 Am sources were used for irradiating samples of CR-39 SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10N NaOH+1 ml CH 3 OH) at 60 °C to detect alpha particle in short time in CR-39 detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 2.73 μm/h. Both the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentrations of CH 3 OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25N NaOH at 70 °C for etching time equals 5 h. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. - Highlights: • The value of bulk etching rate is equal to 2.73 μm/h. • Fast detection of alpha particles in CR-39 detectors. • Samples of CR-39 have been irradiated with fission fragments. • Etching efficiency was determined

  4. Calculation of absorbed fractions to human skeletal tissues due to alpha particles using the Monte Carlo and 3-d chord-based transport techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, J.G. [Institute of Radiation Protection and Dosimetry, Av. Salvador Allende s/n, Recreio, Rio de Janeiro, CEP 22780-160 (Brazil); Watchman, C.J. [Department of Radiation Oncology, University of Arizona, Tucson, AZ, 85721 (United States); Bolch, W.E. [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL, 32611 (United States); Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2007-07-01

    Absorbed fraction (AF) calculations to the human skeletal tissues due to alpha particles are of interest to the internal dosimetry of occupationally exposed workers and members of the public. The transport of alpha particles through the skeletal tissue is complicated by the detailed and complex microscopic histology of the skeleton. In this study, both Monte Carlo and chord-based techniques were applied to the transport of alpha particles through 3-D micro-CT images of the skeletal microstructure of trabecular spongiosa. The Monte Carlo program used was 'Visual Monte Carlo-VMC'. VMC simulates the emission of the alpha particles and their subsequent energy deposition track. The second method applied to alpha transport is the chord-based technique, which randomly generates chord lengths across bone trabeculae and the marrow cavities via alternate and uniform sampling of their cumulative density functions. This paper compares the AF of energy to two radiosensitive skeletal tissues, active marrow and shallow active marrow, obtained with these two techniques. (authors)

  5. Cross Sections for Balmer-Alpha Excitation in Heavy Particle Collisions.

    Science.gov (United States)

    Bae, Young Kun

    Doppler shifted and unshifted Balmer-alpha radiation has been observed in the absolute sense for energetic H('+), H(,2)('+) and H(,3)('+) ions incident on molecular hydrogen by the method of decay inside the target within the energy range of 20 keV to 150 keV. Most of the measurements were based on single-collision conditions, but a simple thick -target experiment has been tried for the case of dissociative excitation of the target molecules by H atoms. The Balmer-alpha radiation emitted by hydrogen and deuterium beams has been used as a diagnostic method of neutral beam parameters. One important neutral beam parameter is the species mix between H('+), H(,2)('+) and H(,3)('+) ion currents produced by the ion source and accelerator. This species mix can be resolved by analysis of the Balmer-alpha radiation if the beam is observed along an off normal axis with sufficient spectral resolution to separate the Doppler shifted radiation components from each other. An impediment to this approach to measuring the ion species is that some of the required cross sections have not been measured. This is the motivation for the presented experimental work. A home made monochromator gave enough optical throughput and spectral resolution for separation of the Doppler shifted lines from the unshifted lines. By selectively varying the target pressure and the distance of travel into the target prior to the observation region, excitation cross sections for three different angular momentum states (3s, 3p and 3d) have been determined. Combinations of a linear polarizer and a half-wave plate were used for polarization measurement. Separation of the individual Zeeman levels have been tried for the 3p state from the information obtained from the polarization. Theoretical estimates of the cascading corrections have been applied in the case of both thin and thick targets. The intensity development equations for thick targets also have been derived. Cross sections for 3s production show

  6. Detection of the ternary alpha particles from 252Cr spontaneous source with timepix pixeleted detector

    International Nuclear Information System (INIS)

    Ahmadov, G.S.; Telezhnikov, S.A.; Ahmadov, F.I.; Garibov, A.A.; Ahmadov, G.S.; Ahmadov, F.I.; Granja, C.; Pospisil, S.

    2013-01-01

    A third charged particle is emitted besides the two main fission fragments in ternary fission. Because of the ternary fission is a unique tool to explore the dynamics and structure of atomic nuclei by probing the fissioning system near the scission point and observing fissioning reaction and decay mechanisms main tool to study nuclear fission processes

  7. The maximum entropy determination of nuclear densities of calcium isotopes from elastic scattering of alpha particles

    International Nuclear Information System (INIS)

    Engel, Y.M.; Friedman, E.; Levine, R.D.

    1982-01-01

    Radial moments of the real part of the optical potential for elastic scattering of 104 MeV α particles are used as constraints, in determining the nuclear density of maximal entropy. The potential is related to the density by the folding model. (orig.)

  8. Magnetic dynamics of small alpha-Fe2O3 and NiO particles

    DEFF Research Database (Denmark)

    Lefmann, K.; Bødker, Franz; Hansen, Mikkel Fougt

    1999-01-01

    particles, we observed a clear double peak in the energy distribution of the antiferromagnetic signal, in addition to a quasi-elastic peak. We interpret the double peak to respresent collective magnetic excitations. Broadening of the central quasi-elastic peak with increasing temprature is interpreted...

  9. The measurement and modeling of alpha-particle-induced charge collection in dynamic memories

    International Nuclear Information System (INIS)

    Oldiges, P.J.

    1989-01-01

    This thesis addresses the problem of α-particle-induced charge collection in high-density dynamic random access memories. A novel technique for the measurement of charge collection in high-density memory cells and bit lines due to α-particle strikes was developed. The technique involves D.C. tests on simple test structures with an α-particle source on the device package as a lid. The advantages of this new measurement technique are: the method allows for in-situ measurements of charge collection on both MOS capacitors and bit lines found in present-day memories; the on-chip measurement technique minimizes errors due to external probes loading the device under test; the measurements can be controlled by a personal computer, with the data being able to be reduced on the same machine. Results obtained using this new measurement technique show that the charge collection is found to depend upon test-structure size and the configuration of its neighbors. Results of two-dimensional simulations of charge flow along the surface of an MOS capacitor from current injection due to an α-particle strike indicate that a spatial potential variation of 0.5V may occur between the point of current injection and capacitor edge for a 1M dRAM capacitor

  10. Evolution of Proton and Alpha Particle Velocities through the Solar Cycle

    Science.gov (United States)

    Ďurovcová, T.; Šafránková, J.; Němeček, Z.; Richardson, J. D.

    2017-12-01

    Relative properties of solar wind protons and α particles are often used as indicators of a source region on the solar surface, and analysis of their evolution along the solar wind path tests our understanding of physics of multicomponent magnetized plasma. The paper deals with the comprehensive analysis of the difference between proton and α particle bulk velocities at 1 au with a special emphasis on interplanetary coronal mass ejections (ICMEs). A comparison of about 20 years of Wind observations at 1 au with Helios measurements closer to the Sun (0.3-0.7 au) generally confirms the present knowledge that (1) the differential speed between both species increases with the proton speed; (2) the differential speed is lower than the local Alfvén speed; (3) α particles are faster than protons near the Sun, and this difference decreases with the increasing distance. However, we found a much larger portion of observations with protons faster than α particles in Wind than in Helios data and attributed this effect to a preferential acceleration of the protons in the solar wind. A distinct population characterized by a very small differential velocity and nearly equal proton and α particle temperatures that is frequently observed around the maximum of solar activity was attributed to ICMEs. Since this population does not exhibit any evolution with increasing collisional age, we suggest that, by contrast to the solar wind from other sources, ICMEs are born in an equilibrium state and gradually lose this equilibrium due to interactions with the ambient solar wind.

  11. Results of solid state nuclear track detector technique application in radon detection, by alpha particles tracks, for uranium prospecting in Caetite (BA-Brazil)

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Khouri, M.T.F.C.

    1988-11-01

    The solid state nuclear track detector technique has been used in radon detection, by alpha particles tracks for uranium prospecting on the ground in Caetite city (Bahia-Brazil). The sensitive film to alpha particles used were CA 8015 exposed during 15 days and the results of three anomalies of this region are showed in a form of maps, made with the density of tracks obtained, and were compared with scintillation counter measurements. The technique showed to be simple and an effective auxiliary for the prospection of uranium ore bodies. The initial uranium exploration costs can be reduced by using this technique. (author) [pt

  12. Alpha particle effects in burning tokamak plasmas: overview and specific examples

    International Nuclear Information System (INIS)

    Sigmar, D.J.

    1986-07-01

    Using the total power balance of an ignited tokamak plasma as a guideline, a range of alpha driven effects is surveyed regarding their impact on achieving and maintaining fusion burn. Specific examples of MHD and kinetic modes and multi species transport dynamics are discussed, including the possible interaction of these categories of effects. This power balance approach rather than a straightforward enumeration of possible effects serves to reveal their non-linear dependence and the ensuing fragility of our understanding of the approach to and maintenance of ignition. Specific examples are given of the interaction between α-power driven sawtoothing and ideal MHD stability, and direct α-effects on MHD modes including kinetic corrections. Anomalous ion heat transport and central impurity peaking mechanisms and anomalous and collisional α-transport including the ambipolar electric field are discussed

  13. Concept design of a time-of-flight spectrometer for the measurement of the energy of alpha particles.

    Science.gov (United States)

    García-Toraño, E

    2018-04-01

    The knowledge of the energies of the alpha particles emitted in the radioactive decay of a nuclide is a key factor in the construction of its decay scheme. Virtually all existing data are based on a few absolute measurements made by magnetic spectrometry (MS), to which most other MS measurements are traced. An alternative solution would be the use of time-of-flight detectors. This paper discusses the main aspects to be considered in the design of such detectors, and the performances that could be reasonably expected. Based on the concepts discussed here, it is estimated that an energy resolution about 2.5keV may be attainable with a good quality source. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Time-dependent Occurrence Rate of Electromagnetic Cyclotron Waves in the Solar Wind: Evidence for the Effect of Alpha Particles?

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, G. Q.; Feng, H. Q. [Institute of Space Physics, Luoyang Normal University, Luoyang (China); Wu, D. J. [Purple Mountain Observatory, CAS, Nanjing (China); Chu, Y. H. [Institute of Space Science, National Central University, Chungli, Taiwan (China); Huang, J. [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing (China)

    2017-09-20

    Previous studies revealed that electromagnetic cyclotron waves (ECWs) near the proton cyclotron frequency exist widely in the solar wind, and the majority of ECWs are left-handed (LH) polarized waves. Using the magnetic field data from the STEREO mission, this Letter carries out a survey of ECWs over a long period of 7 years and calculates the occurrence rates of ECWs with different polarization senses. Results show that the occurrence rate is nearly a constant for the ECWs with right-handed polarization, but it varies significantly for the ECWs with LH polarization. Further investigation of plasma conditions reveals that the LH ECWs take place preferentially in a plasma characterized by higher temperature, lower density, and larger velocity. Some considerable correlations between the occurrence rate of LH ECWs and the properties of ambient plasmas are discussed. The present research may provide evidence for the effect of alpha particles on the generation of ECWs.

  15. Electron capture by alpha particles from helium atoms in a Coulomb-Born distorted-wave approximation

    International Nuclear Information System (INIS)

    Ghanbari-Adivi, E; Ghavaminia, H

    2012-01-01

    A three-body Coulomb-Born continuum distorted-wave approximation is applied to calculate the differential and total cross sections for single-electron exchange in the collision of fast alpha particles with helium atoms in their ground states. The applied first-order distorted wave theory satisfies correct Coulomb boundary conditions. Both post and prior forms of the transition amplitude are calculated. The nuclear-screening effect of the passive electron on the differential and total cross sections is investigated. The results are compared with those of other theories and with the available experimental data. For differential cross sections, the comparisons show a reasonable agreement with empirical measurements at higher impact energies. The agreement between experimental data and the present calculations for total cross sections with the average of the post and prior forms of the transition amplitude is reasonable at all the specified energies.

  16. Use of the Kalman filter in signal processing to reduce beam requirements for alpha-particle diagnostics

    International Nuclear Information System (INIS)

    Cooper, W.S.

    1986-01-01

    Several techniques proposed for diagnosing the velocity distribution of fast alpha-particles in a burning plasma require the injection of a beam of fast neutral atoms as probes. The author discusses how improving signal detection techniques is a high leverage factor in reducing the cost of the diagnostic beam. Optimal estimation theory provides a computational algorithm, the Kalman filter, that can optimally estimate the amplitude of a signal with arbitrary (but known) time dependence in the presence of noise. In one example presented, based on a square-wave signal and assumed noise levels, the Kalman filter achieves an enhancement of signal detection efficiency of about a factor of 10 (as compared with the straightforward observation of the signal superimposed on noise) with an observation time of 100 signal periods

  17. Development of diamond thin film-based alpha particle detectors for online assay of plutonium content in corrosive liquid medium

    International Nuclear Information System (INIS)

    Nuwad, J.; Jain, Dheeraj; Manoj, N.; Sudarsan, V.; Panja, S.; Dhami, P.S.

    2014-01-01

    In the present work, diamond thin films were prepared using microwave plasma chemical vapor deposition (MPCVD) method and characterized using XRD, OES, SEM, Raman spectroscopy and I-V techniques. These films were subjected to annealing and chemical cleaning for further improving the film quality. Surface metallization was obtained by gold deposition using PVD. These films were configured in semiconductor-insulator-metal heterostructure and mounted in SS shells. Gold coated growth surface (detector's active area) was sealed by chemical resistant sealing. Suitable bias was applied between the front and back electrical contacts to enable charge collection generated upon alpha particle interaction with diamond. The photograph of developed detector in the lab is shown

  18. Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Gregory P.

    2004-11-24

    The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively localized in vitro on tumor cells that expressed both antigens and were capable of effective tumor localization in in vivo studies.

  19. Optimizing the Delivery of Short-Lived Alpha Particle-Emitting Isotopes to Solid Tumors

    International Nuclear Information System (INIS)

    Adams, Gregory P.

    2004-01-01

    The underlying hypothesis of this project was that optimal alpha emitter-based radioimmunotherapy (RAIT) could be achieved by pairing the physical half-life of the radioisotope to the biological half-life of the targeting vehicle. The project had two specific aims. The first aim was to create and optimize the therapeutic efficacy of 211At-SAPS-C6.5 diabody conjugates. The second aim was to develop bispecific-targeting strategies that increase the specificity and efficacy of alpha-emitter-based RAIT. In the performance of the first aim, we created 211At-SAPS-C6.5 diabody conjugates that specifically targeted the HER2 tumor associated antigen. In evaluating these immunoconjugates we determined that they were capable of efficient tumor targeting and therapeutic efficacy of established human tumor xenografts growing in immunodeficient mice. We also determined that therapeutic doses were associated with late renal toxicity, likely due to the role of the kidneys in the systemic elimination o f these agents. We are currently performing more studies focused on better understanding the observed toxicity. In the second aim, we successfully generated bispecific single-chain Fv (bs-scFv) molecules that co-targeted HER2 and HER3 or HER2 and HER4. The in vitro kinetics and in vivo tumor-targeting properties of these molecules were evaluated. These studies revealed that the bs-scFv molecules selectively localized in vitro on tumor cells that expressed both antigens and were capable of effective tumor localization in in vivo studies

  20. Production of medically useful bromine isotopes via alpha-particle induced nuclear reactions

    Science.gov (United States)

    Breunig, Katharina; Scholten, Bernhard; Spahn, Ingo; Hermanne, Alex; Spellerberg, Stefan; Coenen, Heinz H.; Neumaier, Bernd

    2017-09-01

    The cross sections of α-particle induced reactions on arsenic leading to the formation of 76,77,78Br were measured from their respective thresholds up to 37 MeV. Thin sediments of elemental arsenic powder were irradiated together with Al degrader and Cu monitor foils using the established stacked-foil technique. For determination of the effective α-particle energies and of the effective beam current through the stacks the cross-section ratios of the monitor nuclides 67Ga/66Ga were used. This should help resolve discrepancies in existing literature data. Comparison of the data with the available excitation functions shows some slight energy shifts as well as some differences in curve shapes. The calculated thick target yields indicate, that 77Br can be produced in the energy range Eα = 25 → 17 MeV free of isotopic impurities in quantities sufficient for medical application.

  1. Production of medically useful bromine isotopes via alpha-particle induced nuclear reactions

    Directory of Open Access Journals (Sweden)

    Breunig Katharina

    2017-01-01

    Full Text Available The cross sections of α-particle induced reactions on arsenic leading to the formation of 76,77,78Br were measured from their respective thresholds up to 37 MeV. Thin sediments of elemental arsenic powder were irradiated together with Al degrader and Cu monitor foils using the established stacked-foil technique. For determination of the effective α-particle energies and of the effective beam current through the stacks the cross-section ratios of the monitor nuclides 67Ga/66Ga were used. This should help resolve discrepancies in existing literature data. Comparison of the data with the available excitation functions shows some slight energy shifts as well as some differences in curve shapes. The calculated thick target yields indicate, that 77Br can be produced in the energy range Eα = 25 → 17 MeV free of isotopic impurities in quantities sufficient for medical application.

  2. Alpha-particles induce preneoplastic transformation of rat tracheal epithelial cells in culture

    International Nuclear Information System (INIS)

    Thomassen, D.G.; Seiler, F.A.; Shyr, L.-J.; Griffith, W.C.

    1990-01-01

    To characterize the potential role of high-l.e.t. radiation in respiratory carcinogenesis, the cytotoxic and transforming potency of 5.5 MeV α-particles from electroplated sources of 238 Pu were determined using primary cultures of rat tracheal epithelial cells. RBE for cell killing by α-particles versus X-rays varied with dose, and ranged between 4 and 1.5 for α doses in the range 0.2-4 Gy. At equally toxic doses (relative survival 0.18-0.2), all three agents induced similar frequencies of preneoplastic transformation. For preneoplastic transformation induced by doses of α- and X-radiations giving 80 per cent toxicity, an α RBE of 2.4 was derived. The similar RBEs for cell killing and for preneoplastic transformation suggest an association between the type or degree of radiation-induced damage responsible for both cell killing and cell transformation. (author)

  3. BJT detector with FPGA-based read-out for alpha particle monitoring

    International Nuclear Information System (INIS)

    Tyzhnevyi, V; Dalla Betta, G-F; Rovati, L; Verzellesi, G; Zorzi, N

    2011-01-01

    In this work we introduce a new prototype of readout electronics (ALPHADET), which was designed for an α-particle detection system based on a bipolar junction transistor (BJT) detector. The system uses an FPGA, which provides many advantages at the stage of prototyping and testing the detector. The main design and electrical features of the board are discussed in this paper, along with selected results from the characterization of ALPHADET coupled to BJT detectors.

  4. SCALP: Scintillating ionization chamber for ALPha particle production in neutron induced reactions

    Science.gov (United States)

    Galhaut, B.; Durand, D.; Lecolley, F. R.; Ledoux, X.; Lehaut, G.; Manduci, L.; Mary, P.

    2017-09-01

    The SCALP collaboration has the ambition to build a scintillating ionization chamber in order to study and measure the cross section of the α-particle production in neutron induced reactions. More specifically on 16O and 19F targets. Using the deposited energy (ionization) and the time of flight measurement (scintillation) with a great accuracy, all the nuclear reaction taking part on this project will be identify.

  5. Alpha particles-and 3He inelastic scattering by 124Sn in the coulomb barrier region

    International Nuclear Information System (INIS)

    Appoloni, C.R.

    1976-01-01

    Angular distributions for inelastic scattering of α and 3 He particles in 124 Sn at the incident energies around Coulomb barrier were measured using the 8UD Pelletron Tandem Accelerator of The University of Sao Paulo. The results were analysed by DWBA with a collective form factor including the effects due to the interference between coulomb and nuclear excitations with the code PATIWEN (Ba75). The nuclear deformation parameters for the one phonon levels (2 + and 3 - ) have been obtained. (Author) [pt

  6. Scenarios for the nonlinear evolution of alpha particle induced Alfven wave instability

    International Nuclear Information System (INIS)

    Berk, H.L.; Breizman, B.N.; Ye, Huanchun.

    1992-03-01

    Various nonlinear scenarios are given for the evolution of energetic particles that are slowing down in a background plasma and simultaneously causing instability of the background plasma waves. If the background damping is sufficiently weak, a steady-state wave is established as described by Berk and Breizman. For larger background damping rate pulsations develop. Saturation occurs when the wave amplitude rises to where the wave trapping frequency equals the growth rate. The wave then damps due to the small background dissipation present and a relatively long quiet interval exists between bursts while the free energy of the distribution is refilled by classical transport. In this scenario the anomalous energy loss of energetic particles due to diffusion is small compared to the classical collisional energy exchange with the background plasma. However, if at the trapping frequency, the wave amplitude is large enough to cause orbit stochasticity, a phase space ''explosion'' occurs where the wave amplitudes rise to higher levels which leads to rapid loss of energetic particles

  7. Alpha-particle doses to human organs and tissues from internally-deposited 226Ra and 228Ra

    International Nuclear Information System (INIS)

    Keane, A.T.; Schlenker, R.A.

    1981-01-01

    Estimation of radiation doses to the soft tissues from internally-deposited 226 Ra and 228 Ra is relevant to an investigation of soft-tissue malignancies in radium-exposed persons being conducted at the Center for Human Radiobiology. Alpha-particle doses in a 50-year period following a single injection of 226 Ra or 228 Ra are presented for 31 soft tissues and organs of the adult human. The dose estimates were derived from the ICRP alkaline earth model fitted to data on retention of 226 Ra in soft tissues and bone, combined with reported ratios of 226 Ra to Ca in soft tissue and bone at natural levels and the distribution of Ca in the tissues of Reference Man (ICRP23). The median of the 31 organ and tissue doses from the α-particles of 226 Ra itself is 0.08 rad per injected μCi. An additional average dose of 0.01 rad per μCi 226 Ra daughter products produced in soft tissue or transferred from bone to soft tissue. Soft-tissue doses from α-particles of the 228 Ra decay series are about six times those from 226 Ra α-particles for equal injected activities of 228 Ra and 226 Ra, with the assumption that 228 Ra daughter products do not transfer from the organ in which they are produced. The 50-year dose to the red marrow of bone from α-particles originating in bone is 0.55 rad per μCi 226 Ra injected and 1.0 rad per μCi 228 Ra injected. For ingestion by dial painters of luminous compound containg 226 Ra or 228 Ra with a daughter-to-parent activity ratio of 0.5, the dose to the mucosal alyer of the lower large intestine from α-particles originating in the gut contents is about 0.1 rad per μCi systemic intake of 226 Ra or 228 Ra

  8. Luminescence yield in irradiating gases by X-rays and alpha particles

    International Nuclear Information System (INIS)

    Combecher, D.

    1973-01-01

    In this paper, the measurable light emission in the irradiation of gases as modle substances has been quantitatively determined. The gases Ar, H 2 , N 2 , air, and C 3 H 8 were irradiated with X-rays and α-particles at a pressure of 730 torr. The emitted light was measured in the spectral range between the short-wave absorption edge of the gases and 6000 A (spectral resolution: 20 A). The spectral light yield was determined from the efficiency of the apparatus and from the total energy absorbed in the gases. (HK) [de

  9. Laser and alpha particle characterization of floating-base BJT detector

    International Nuclear Information System (INIS)

    Tyzhnevyi, V.; Batignani, G.; Bosisio, L.; Dalla Betta, G.-F.; Verzellesi, G.; Zorzi, N.

    2010-01-01

    In this work, we investigate the detection properties of existing prototypes of BJT detectors operated with floating base. We report about results of two functional tests. The charge-collection properties of BJT detectors were evaluated by means of a pulsed laser setup. The response to α-particles emitted from radioactive 241 Am source are also presented. Experimental results show that current gains of about 450 with response times in the order of 50 μs are preserved even in this non-standard operation mode, in spite of a non-optimized structure.

  10. ‘Rutherford’s experiment’ on alpha particles scattering: the experiment that never was

    Science.gov (United States)

    Leone, M.; Robotti, N.; Verna, G.

    2018-05-01

    The so-called Rutherford’s experiment, as it is outlined in many physics textbooks, is a case in point of the flaws around the history at the educational level of one of the decisive event of modern physics: the discovery that the atom has a nucleus. This paper shows that this alleged experiment is a very approximate and very partial synthesis of a series of different particle scattering experiments, starting with that carried out by Rutherford in 1906 and ending with Geiger and Marsden’s 1913 experiments.

  11. Measurement of the thickness and homogeneity of thin foils by slowing down alpha particles

    International Nuclear Information System (INIS)

    Bimbot, R.; Della Negra, S.; Deprun, C.; Gardes, D.; Rivet, M.F.

    1979-01-01

    The energy loss of 8.785 MeV α particles passing through a thin foil is used to measure the foil thickness. The measurement is performed in various points of the target, the abscissa and ordinate of which are set with precision from the outside of the chamber. This gives a thickness map of the target. The working up of the data, and the use of energy loss tables are made in a standard way. The absolute uncertainty is of some percent for 100 μg/cm 2 foils. The technique has been refined to reach the same precision for 10 μg/cm 2 targets [fr

  12. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 70 0 C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author) [pt

  13. A fundamental parameters approach to calibration of the Mars Exploration Rover Alpha Particle X-ray Spectrometer

    Science.gov (United States)

    Campbell, J. L.; Lee, M.; Jones, B. N.; Andrushenko, S. M.; Holmes, N. G.; Maxwell, J. A.; Taylor, S. M.

    2009-04-01

    The detection sensitivities of the Alpha Particle X-ray Spectrometer (APXS) instruments on the Mars Exploration Rovers for a wide range of elements were experimentally determined in 2002 using spectra of geochemical reference materials. A flight spare instrument was similarly calibrated, and the calibration exercise was then continued for this unit with an extended set of geochemical reference materials together with pure elements and simple chemical compounds. The flight spare instrument data are examined in detail here using a newly developed fundamental parameters approach which takes precise account of all the physics inherent in the two X-ray generation techniques involved, namely, X-ray fluorescence and particle-induced X-ray emission. The objectives are to characterize the instrument as fully as possible, to test this new approach, and to determine the accuracy of calibration for major, minor, and trace elements. For some of the lightest elements the resulting calibration exhibits a dependence upon the mineral assemblage of the geological reference material; explanations are suggested for these observations. The results will assist in designing the overall calibration approach for the APXS on the Mars Science Laboratory mission.

  14. Inner heliosphere spatial gradients of GCR protons and alpha particles in the low GeV range

    Science.gov (United States)

    Gieseler, J.; Boezio, M.; Casolino, M.; De Simone, N.; Di Felice, V.; Heber, B.; Martucci, M.; Picozza, P.

    2013-12-01

    The spacecraft Ulysses was launched in October 1990 in the maximum phase of solar cycle 22, reached its final, highly inclined (80.2°) Keplerian orbit around the Sun in February 1992, and was finally switched off in June 2009. The Kiel Electron Telescope (KET) aboard Ulysses measures electrons from 3 MeV to a few GeV and protons and helium in the energy range from 6 MeV/nucleon to above 2 GeV/nucleon. In order to investigate the radial and latitudinal gradients of galactic cosmic rays (GCR), it is essential to know their intensity variations for a stationary observer in the heliosphere because the Ulysses measurements reflect not only the spatial but also the temporal variation of the energetic particle intensities. This was accomplished in the past with the Interplanetary Monitoring Platform-J (IMP 8) until it was lost in 2006. Fortunately, the satellite-borne experiment PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) was launched in June 2006 and can be used as a reliable 1 AU baseline for measurements of the KET aboard Ulysses. With these tools at hand, we have the opportunity to determine the spatial gradients of GCR protons and alpha particles at about 0.1 to 1 GeV/n in the inner heliosphere during the extended minimum of solar cycle 23. We then compare these A0 cycle.

  15. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang; Wu Lijun

    2007-01-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of γ-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process ( G -methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy α-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose α-particle irradiation and nitric oxide generated by irradiation was also very important in this process

  16. Nuclear densities of 1fsub(7/2) nuclei from elastic alpha-particle scattering

    International Nuclear Information System (INIS)

    Friedman, E.; Gils, H.J.; Rebel, H.

    1983-12-01

    The elastic scattering of 104 MeV α particles by sup(40,42,43,44,48)Ca, 50 Ti, 51 V, 52 Cr has been analyzed by phenomenological and semimicroscopic optical potentials in order to get information on isotopic and isotonic differences of the α particle optical potentials and of nuclear matter densities. The phenomenological optical potentials based on a Fourier-Bessel description of the real part reveal different behaviour in size and shape for the isotonic chain as compared to the isotopic chain. Odd-even effects are also indicated to be different for isotones and isotopes. The semi-microscopic analyses use a single-folding model with a density-dependent effective αN-interaction including a realistic local density approximation. The calculated potentials are fully consistent with the phenomenological ones. Isopotic and isotonic differences of the nuclear matter densities obtained from the folding model in general show a similar behavior as the optical potential differences. The results on matter densities are compared to other investigations. (orig.) [de

  17. Is the gas-particle partitioning in alpha-pinene secondary organic aerosol reversible?

    Science.gov (United States)

    Grieshop, Andrew P.; Donahue, Neil M.; Robinson, Allen L.

    2007-07-01

    This paper discusses the reversibility of gas-particle partitioning in secondary organic aerosol (SOA) formed from α-pinene ozonolysis in a smog chamber. Previously, phase partitioning has been studied quantitatively via SOA production experiments and qualitatively by perturbing temperature and observing particle evaporation. In this work, two methods were used to isothermally dilute the SOA: an external dilution sampler and an in-chamber technique. Dilution caused some evaporation of SOA, but repartitioning took place on a time scale of tens of minutes to hours-consistent with an uptake coefficient on the order of 0.001-0.01. However, given sufficient time, α-pinene SOA repartitions reversibly based on comparisons with data from conventional SOA yield experiments. Further, aerosol mass spectrometer (AMS) data indicate that the composition of SOA varies with partitioning. These results suggest that oligomerization observed in high-concentration laboratory experiments may be a reversible process and underscore the complexity of the kinetics of formation and evaporation of SOA.

  18. Time variations of magnetospheric intensities of outer zone protons, alpha particles and ions (Z greater than or equal to 2). Ph.D. Thesis

    Science.gov (United States)

    Randall, B. A.

    1973-01-01

    A comprehensive study of the temporal behavior of trapped protons, alpha particles and ions (Z 2) in outer zone of the earth's magnetosphere has been made. These observations were made by the Injun V satellite during the first 21 months of operation, August 1968 to May 1970. Rapid increases in the observed number of particles followed by slower exponential decay characterize the data. Comparisons are made with the temporal behavior of interplanetary particles of the same energy observed by Explorer 35. Increases in the trapped fluxes generally correspond to enhanced interplanetary activity. The energy spectra of protons and alpha particles at L = 3 have similar shapes when compared on an energy per charge basis while the respective polar cap spectra have similar shape on an energy per nucleon basis. Apparent inward trans-L motion of energetic protons is observed. These particles are diffused inward by a process involving fluctuating electric fields. The loss of trapped low altitude protons, alpha particles and ions (Z 2) is controlled by coulombic energy loss in the atmosphere.

  19. Determination of the proton and alpha-particle light-response functions for the KamLAND, BC-501A and BC-517H liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Braizinha, B. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Esterline, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, Duke University, Durham, NC 27708 (United States); Karwowski, H.J. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Tornow, W., E-mail: tornow@tunl.duke.ed [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, Duke University, Durham, NC 27708 (United States)

    2010-11-21

    A cylindrical 5.1 cmx5.1 cm scintillator cell filled with the KamLAND liquid scintillator has been exposed to monoenergetic neutron beams produced via the {sup 2}H(d,n){sup 3}He reaction to measure the proton light-response function for energies up to 10 MeV. Using Birks' recipe, the {alpha}-particle light-response function was derived from these data. The same method was applied to the BC-501A and BC-517H liquid scintillators to check on the systematic accuracy of the present data. The proton and {alpha}-particle light-response functions are needed to correct the KamLAND antineutrino prompt energy spectrum for background effects caused by the reaction {sup 13}C({alpha},n){sup 16}O. Especially, the geo-antineutrino energy regime measured in the KamLAND experiment is contaminated by background events from this reaction.

  20. CONSOLIDATION AND COMPACTION OF POWDER MIXTURES .2. BINARY-MIXTURES OF DIFFERENT PARTICLE-SIZE FRACTIONS OF ALPHA-LACTOSE MONOHYDRATE

    NARCIS (Netherlands)

    RIEPMA, KA; VEENSTRA, J; DEBOER, AH; BOLHUIS, GK; ZUURMAN, K; LERK, CF; VROMANS, H

    1991-01-01

    Binary mixtures of different particle size fractions of alpha-lactose monohydrate were compacted into tablets. The results showed decreased crushing strengths and decreased internal specific surface areas of the tablets as compared with the values calculated by linear interpolation of the data

  1. Generalized Dependence of Semi-Microscopic Folding-Model Parameters for Alpha-Particles in the Field of Low and Medium Energy

    CERN Document Server

    Kuterbekov, K A; Penionzhkevich, Yu E; Zholdybaev, T K

    2003-01-01

    Energy and mass dependences of the semi-microscopic alpha-particle potential parameters have been investigated for the first time. In general, a good description of elastic and inelastic differential and total reaction cross sections for different nuclei using the revealed global parameters has been obtained within the framework of semi-microscopic approaches.

  2. Gross Sales Tax Collections

    Data.gov (United States)

    City of Jackson, Mississippi — This data is captured directly from the MS Department of Revenue and specific to the City of Jackson. It is compiled from Gross Sales Tax reported by taxpayers each...

  3. Loovkirjutamist õpetab Philip Gross

    Index Scriptorium Estoniae

    2011-01-01

    T.S. Elioti luulepreemia laureaat Philip Gross on Tallinna Ülikooli talvekooli rahvusvahelise kursuse "Poetry: A Conversation between Words and Silence" läbiviija. Oma seminarides keskendub ta lisaks loovkirjutamisele ka loova lugemise vajadusele

  4. Determination of oxygen impurity in high purity materials by charged particle activation analysis using alpha projectiles

    International Nuclear Information System (INIS)

    Chowdhury, D.P.; Pal, S.; Arunachalam, J.; Verma R.; Gangadharan, S.

    1992-01-01

    40 MeV α-particles have been used to determine oxygen impurity at ppm levels in silicon, copper, and stainless steel, through the radiochemical separation of 18 F from the matrix. The separation of 18 F has been carried out by two techniques, viz. distillation of H 2 SiF 6 and precipitation of KBF 4 and some modification has been applied in the separation, depending on the nature of interferences from the matrix. Instrumental approach was also carried out to determine the oxygen impurity at ≥ 100 ppm in Si matrix because this approach is not possible in Cu and stainless steel samples due to matrix activity. (author) 10 refs.; 1 fig.; 5 tabs

  5. The study of creep in stainless steel irradiated with fast neutron and alpha particles

    International Nuclear Information System (INIS)

    Correa, D.A.C.

    1985-01-01

    The objective of the present work is to study the creep behavior of the 316 type stainless steel 50% cold worked in different conditions of temperature and applied stress, after neutron radiation and Alfa particles implantation. For this experiment, non-irradiated samples, samples irradiated in the research reactor IEA-R1 with fast neutron (E≥ MeV) up to a fluence of 8.6.10 17 n/cm 2 , and samples implanted with Alfa particles in the cyclotron CV-28 with Helium concentrations of 5 and 26 appm, were creep tested with applied stresses of the 200-300 MPa at temperatures between 650 0 C and 700 0 C. The deformation versus time curves were plotted and it was observed tha the second stage is not well defined, with the creep rate increasing continuously until the occurrence of failure of the material. The study of the effect of increase from 200 MPa to 300 MPa at the same temperature was performed. It can be concluded that this increase produces an approximately 70% reductions in the fracture time of the material, with practically no influence in the total deformation. Samples were tested at different temperatures (650, 675 and 700 0 C) at a same applied stress (200 MPa). It has been observed that a temperature of 50 0 C produces 98,9% of reduction in the fracture time and almost doubles the total deformation. On neutron irradiated samples, creep tests were performed at the same temperature and stress of the non irradiated samples. Comparing the results obtained a tendency of embrittlement due to the neutron irradiation can be observed; no remarkable structure changes were detected due to small fast neutron. Microstructural and metalographic observations were performed before and after each creep test. (author) [pt

  6. Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52MeV.

    Science.gov (United States)

    Ditrói, F; Takács, S; Haba, H; Komori, Y; Aikawa, M

    2016-12-01

    Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. The radioisotope 117m Sn is a very important theranostic (therapeutic + diagnostic) radioisotope, so special care was taken to the results for that isotope. The well-established stacked foil technique followed by gamma-spectrometry with HPGe gamma spectrometers were used. The target and monitor foils in the stack were commercial high purity metal foils. From the irradiated targets 117m Sn, 113 Sn, 110 Sn, 117m,g In, 116m In, 115m In, 114m In, 113m In, 111 In, 110m,g In, 109m In, 108m,g In, 115g Cd and 111m Cd were identified and their excitation functions were derived. The results were compared with the data of the previous measurements from the literature and with the results of the theoretical nuclear reaction model code calculations TALYS 1.8 (TENDL-2015) and EMPIRE 3.2 (Malta). From the cross section curves thick target yields were calculated and compared with the available literature data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Experimental and theoretical investigation of scattering of alpha particles from 13C nuclei

    International Nuclear Information System (INIS)

    Burtebayev, N.; Burtebayeva, D.T.; Baktybayev, M.K.; Duisebayev, B.A.; Ogloblin, A.A.; Demyanova, A.S.; Sakuta, Sh.; Hamada, C.B.; Janseitov, D.M.; Nassurlla, M.; Artemov, S.V.

    2015-01-01

    13 C is a good example of a “normal” nucleus well described by the shell model. Its level scheme is reliably determined up to the excitation energies ~ 10 MeV (see e.g. [1]). However, some new approaches such as the hypothesis of the α-particle condensation suggest that cluster states with an enhanced radius can appear. The famous Hoyle state (0 2 + , E* = 7.65 MeV) in 12 C was considered as the most probable candidate for having such structure. It was also expected that the analogues of the Hoyle state would reveal themselves in some neighboring nuclei, e.g., the ½- (E*= 8.86MeV) state in 13 C. The analysis of the 13 C + α scattering data measured at E (α) = 388 MeV really demonstrated a considerable enhancement of the radius of this particular state. However, the method of extracting the radii used may not be quite adequate at high energies (≥ 100 MeV) when nuclei are too transparent. The existence in 13 C of some states with enhanced dimensions but of different structure was discussed as well. Thus, a neutron halo was identified in the first excited state 3.09 MeV (1/2 + ) by two independent and complementary methods. Consequently, new measurements especially at lower energies are highly desirable

  8. Alpha-particles microbeam irradiation: impact of reactive oxygen species in bystander effect

    International Nuclear Information System (INIS)

    Hanot, M.

    2008-11-01

    Ionizing radiation-induced bystander effects arise in bystander cells that receive signals from directly irradiated cells. To date, free radicals are believed to play an active role in the bystander response, but this is incompletely characterized. To mark temporal and spatial impacts of bystander effect, we employed a precise α-particle microbeam to target a small fraction of sub-confluent osteoblastic cell cultures (MC3T3-E1). We identified the cellular membrane and mitochondria like two distinct places generating reactive oxygen species. The global oxidative stress observed after irradiation was significantly attenuated after filipin treatment, evidencing the pivotal role of membrane in MC3T3-E1 cells bystander response. To determine impact of bystander effect at a cell level, cellular consequences of this membrane-dependant bystander effect were then investigated. A variable fraction of the cell population (10 to 100%) was individually targeted. In this case, mitotic death and micronuclei yield both increased in bystander cells as well as in targeted cells demonstrating a role of bystander signals between irradiated cells in an autocrine or paracrine manner. Our results indicate a complex interaction of direct irradiation and bystander signals that lead to a membrane-dependant amplification of cell responses. (author)

  9. Plasma Heating and Current Drive by Neutral Beam and Alpha Particles

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, M; Okumura, Y [Fusion Research and Development Directorate, Japan Atomic Energy Agency (Japan)

    2012-09-15

    The purpose of plasma heating is to raise the plasma temperature enough to produce a deuterium and tritium reaction (D + T {yields} {sup 4}He + n). The required plasma temperature T is in the range of 10-30 keV. Since the high temperature plasma is confined by a strong magnetic field, injection of energetic ions from outside to heat the plasma is difficult due to the Lorenz force. The most efficient way to heat the plasma by energetic particles is to inject high energy 'neutrals' which get ionized in the plasma. Neutral beam injection (NBI) with a beam energy much above the average kinetic energy of the plasma electrons or ions is used (beam energy typically {approx}40 keV - 1 MeV). This heating scheme is similar to warming up cold water by pouring in hot water. There are two types of neutral beam, called P-NBI and N-NBI (P- and N- means 'positive' and 'negative', respectively). P-NBI uses the acceleration of positively charged ions and their neutralization, while N-NBI uses the acceleration of negative ions (electrons attached to neutral atoms) and their neutralization. Details are given in NBI technology Section. The first demonstration of plasma heating by P-NBI was made in ORMAK and ATC in 1974, while that by N-NBI was made in JT-60U for the first time in 1996. ITER has also adopted the N-NBI system as the heating and current drive system with a beam energy of 1 MeV. Figure A typical bird's eye view of a tokamak with N-NBI and N-NBI (JT-60U) is shown. (author)

  10. Strongly Enhanced Low Energy Alpha-Particle Decay in Heavy Actinide Nuclei and Long-Lived Superdeformed and Hyperdeformed Isomeric States

    CERN Document Server

    Marinov, Amnon; Kolb, D.; Weil, J.L.

    2001-01-01

    Relatively low energy and very enhanced alpha-particle groups have been observed in various actinide fractions produced via secondary reactions in a CERN W target which had been irradiated with 24-GeV protons. In particular, 5.14, 5.27 and 5.53 MeV alpha-particle groups with corresponding half-lives of 3.8(+ -)1.0 y, 625(+ -)84 d and 26(+ -)7 d, have been seen in Bk, Es and Lr-No sources, respectively. The measured energies are a few MeV lower than the known g.s. to g.s. alpha-decays in the corresponding neutron-deficient actinide nuclei. The half-lives are 4 to 7 orders of magnitude shorter than expected from the systematics of alpha-particle decay in this region of nuclei. The deduced evaporation residue cross sections are in the mb region, about 4 orders of magnitude higher than expected. A consistent interpretation of the data is given in terms of production of long-lived isomeric states in the second and third wells of the potential-energy surfaces of the parent nuclei, which decay to the corresponding w...

  11. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-90 0 C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 70 0 C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm 2 /g. Finally, the CR-39 response for low energy alpha particles (E [pt

  12. Calculation of extracted ion beam particle distribution including within-extractor collisions from H-alpha Doppler shift measurements

    International Nuclear Information System (INIS)

    Kim, Tae-Seong; Kim, Jinchoon; In, Sang Ryul; Jeong, Seung Ho

    2008-01-01

    Prototype long pulse ion sources are being developed and tested toward the goal of a deuterium beam extraction of 120 keV/65 A. The latest prototype source consists of a magnetic bucket plasma generator and a four-grid copper accelerator system with multicircular apertures of 568 holes. To measure the angular divergence and the ion species of the ion beam, an optical multichannel analyzer (OMA) system for a Doppler-shifted H-alpha lights was set up at the end of a gas-cell neutralizer. But the OMA data are very difficult to analyze due to a large background level on the top of the three energy peaks (coming from H + , H 2 + , and H 3 + ). These background spectra in the OMA signals seem to result from partially accelerated ion beams in the accelerator. Extracted ions could undergo a premature charge exchange as the accelerator column tends to have a high hydrogen partial pressure from the unused gas from the plasma generator, resulting in a continuous background of partially accelerated beam particles at the accelerator exit. This effect is calculated by accounting for all the possible atomic collision processes and numerically summing up three ion species across the accelerator column. The collection of all the atomic reaction cross sections and the numerical summing up will be presented. The result considerably depends on the background pressure and the ion beam species ratio (H + , H 2 + , and H 3 + ). This effect constitutes more than 20% of the whole particle distribution. And the energy distribution of those suffering from collisions is broad and shows a broad maximum in the vicinity of the half and the third energy region

  13. Monte Carlo particle-trajectory models for neutral cometary gases. I. Models and equations. II. The spatial morphology of the Lyman-alpha coma

    International Nuclear Information System (INIS)

    Combi, M.R.; Smyth, W.H.

    1988-01-01

    The mathematical derivations of various methods employed in the Monte Carlo particle-trajectory model (MCPTM) are presented, and the application of the MCPTM to the calculation of the photochemical heating of the inner coma through the partial thermalization of cometary hydrogen atoms produced by the photodissociation of water is discussed. This model is then used to explain the observed morphology of the spatially extended Ly-alpha comas of comets. The rocket and Skylab images of the Ly-alpha coma of Comet Kohoutek are examined. 90 references

  14. Non-destructive alpha-particle activation analysis of P, Cl, K and Ca in marine macro-alga samples using synthetic multielement reference material as comparative standard

    International Nuclear Information System (INIS)

    Iwata, Y.; Naitoh, H.; Suzuki, N.

    1992-01-01

    A Synthetic Reference Material (SyRM) composed with accurately known amounts of 12 elements has been prepared. The elemental composition of the SyRM is closely similar to that of marine macro-algae sample. The elemental composition of the SyRM was regulated by the starting materials used for the synthesis. The SyRM was used as a comparative standard for non-destructive alpha-particle activation analysis of marine macro-alga samples. P, Cl, K and Ca were determined simultaneously without correction for alpha range due to difference in the elemental composition between the analytical samples and the comparative standard. (author) 19 refs.; 4 tabs

  15. Characteristics and mechanisms of the bystander response in monolayer cell cultures exposed to very low fluences of alpha particles

    International Nuclear Information System (INIS)

    Little, John B.; Azzam, Edouard I.; Toledo, Sonia M. de; Nagasawa, Hatsumi

    2005-01-01

    When confluent cultures of mammalian cells are irradiated with very low fluences of alpha particles whereby only occasional cells receive any radiation exposure, genetic changes are observed in the non-irradiated ('bystander') cells. Upregulation of the p53 damage-response pathway as well as activation of proteins in the MAPK family occurred in bystander cells; p53 was phosphorylated on the serine 15 residue suggesting that the upregulation of p53 was a consequence of DNA damage. Damage signals were transmitted to bystander cells through gap junctions, as confirmed by the use of genetically manipulated cells including connexin43 knockouts. Expression of connexin43 was markedly enhanced by irradiation. A moderate bystander effect was observed for specific gene mutations and chromosomal aberrations. This effect was markedly enhanced in cells defective in the non-homologous end joining DNA repair pathway. Finally, an upregulation of oxidative metabolism occurred in bystander cells; the increased levels of reactive oxygen species appeared to be derived from flavine-containing oxidase enzymes. We hypothesize that genetic effects observed in non-irradiated bystander cells are a consequence of oxidative base damage; >90% of mutations in bystander cells were point mutations. When bystander cells cannot repair DNA double strand breaks, they become much more sensitive to the induction of chromosomal aberrations and mutations, the latter consisting primarily of deletion mutants. While we propose that the genetic effects occurring in bystander cells are a consequence of oxidative stress, the nature of the signal that initiates this process remains to be determined

  16. Establishment of the observing system for boron in steels by alpha-particle track etching method using JAERI reactor

    International Nuclear Information System (INIS)

    Asakura, Kentaro; Shibata, Koji; Sawahata, Hiroyuki; Kawate, Minoru; Harasawa, Susumu

    2003-01-01

    Alpha-particle track etching (ATE) method is most effective in observing boron distribution in steels. Previously, in Japan, neutron irradiation for this method was carried out in the reactor at the Institute of Atomic Energy, Rikkyo University. This reactor, however, was shut down in 1999. Therefore, the establishment of a new system for ATE method has been required and experimental research was performed using the reactor at the Japan Atomic Energy Research Institute (JAERI). It was clarified that the irradiation equipment for medical treatment of the reactor JRR-4 was most suitable for ATE method. The specimen trestle for low radioactive exposure was newly-developed. ATE image obtained by 12h irradiation using this trestle showed a good quality similar to that obtained using Rikkyo's reactor and that obtained using the trestle of the old model. Using this new trestle, the amount of neutron which the worker suffers during the operation at the irradiation equipment decreases from 4μSv/h to 0-1 μSv/h compared with the trestle of the old model. The total amount of thermal neutron after 12 h irradiation was almost same as that under the recommended condition of the reactor at Rikkyo University, 6.5 x 10 14 n cm -2 . (author)

  17. Alpha particles from the photodisintegration of 9Be in the photon energy region 18 to 26 MeV

    International Nuclear Information System (INIS)

    Buchnea, A.; Johnson, R.G.; McNeill, K.G.

    1978-01-01

    Alpha particles from the 9 Be(γ,n) 8 Be(16.6) and 9 Be(γ,α 0 ) 5 He reactions were studied in the photon energy region 18 to 26 MeV; the results yielded a combined integrated cross section of 13.1 +- 2 MeV mb and an upper limit on the integrated (γ,α 0 ) cross section of 4.0 MeV mb. This agrees within error with the integrated cross section of Becchi, Meneghetti, Sanzone, and Vitale, 10 +- 2 MeV mb, which would contain about 50% of any contribution from the (γ,α 0 ) reaction. These reactions together with the 9 Be(γ,n 1 ) 8 Be reaction (which has an integrated cross section of 2.4 +- 0.4 MeV mb) are the major reaction channels contributing to the total photoneutron cross section in this energy region. Their sum, 15.5 MeV mb, agrees well with the results of Nathans and Halpern and Hughes, Sambell, Muirhead, and Spicer but disagrees with that of Costa, Pasqualini, Piragino, and Roasio. (author)

  18. Studying the Range of Incident Alpha Particles on Cu , Ge , Ag , Cd , Te and Au, With Energy (4-15 MeV)

    International Nuclear Information System (INIS)

    Kadhim, R.O.; Jasim, W.N.

    2015-01-01

    In this paper theoretical calculation of the range for alpha particles with the energy range (4 – 15)MeV when passing in some metallic media (Cu , Ge , Ag , Cd , Te and Au).Semi empirical formula was used in addition to (SRIM-2012) program. The Semi empirical equation was programmed to calculate the range using Matlab Language.The results of the range in these media were compared with the results obtained from SRIM-2012 and )(2011)Andnet) results.There was good agreement among the semi empirical equation result , SRIM- 2012 results and with )(2011)Andnet) results in the low energy.The results showed exponential relation between the range of alpha particles in these media and the velocity of the particles.By recourse with SRIM- 2012 results and application them in Matlab program and by using Curve Fitting Tool we extraction equation with its constants to calculate the range of alpha particles in any element of these six elements with the energy range (4 – 15)MeV.The maximum deviation between the results from the semi empirical calculation and SRIM-2012 results was calculated the statistical test ( kstest2) in Matlab program

  19. Calculation of effective atomic number and electron density of essential biomolecules for electron, proton, alpha particle and multi-energetic photon interactions

    Science.gov (United States)

    Kurudirek, Murat; Onaran, Tayfur

    2015-07-01

    Effective atomic numbers (Zeff) and electron densities (Ne) of some essential biomolecules have been calculated for total electron interaction, total proton interaction and total alpha particle interaction using an interpolation method in the energy region 10 keV-1 GeV. Also, the spectrum weighted Zeff for multi-energetic photons has been calculated using Auto-Zeff program. Biomolecules consist of fatty acids, amino acids, carbohydrates and basic nucleotides of DNA and RNA. Variations of Zeff and Ne with kinetic energy of ionizing charged particles and effective photon energies of heterogeneous sources have been studied for the given materials. Significant variations in Zeff and Ne have been observed through the entire energy region for electron, proton and alpha particle interactions. Non-uniform variation has been observed for protons and alpha particles in low and intermediate energy regions, respectively. The maximum values of Zeff have found to be in higher energies for total electron interaction whereas maximum values have found to be in relatively low energies for total proton and total alpha particle interactions. When it comes to the multi-energetic photon sources, it has to be noted that the highest Zeff values were found at low energy region where photoelectric absorption is the pre-dominant interaction process. The lowest values of Zeff have been shown in biomolecules such as stearic acid, leucine, mannitol and thymine, which have highest H content in their groups. Variation in Ne seems to be more or less the same with the variation in Zeff for the given materials as expected.

  20. Factors affecting the energy resolution in alpha particle spectrometry with silicon diodes; Fatores que influenciam a resolucao em energia na espectrometria de particulas alfa com diodos de Si

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Fabio de. E-mail: f.camargo@bol.com.br

    2005-07-01

    In this work are presented the studies about the response of a multi-structure guard rings silicon diode for detection and spectrometry of alpha particles. This ion-implanted diode (Al/p{sup +}/n/n{sup +}/Al) was processed out of 300 {mu}m thick, n type substrate with a resistivity of 3 k{omega}{center_dot}cm and an active area of 4 mm{sup 2}. In order to use this diode as a detector, the bias voltage was applied on the n{sup +} side, the first guard ring was grounded and the electrical signals were readout from the p{sup +} side. These signals were directly sent to a tailor made preamplifier, based on the hybrid circuit A250 (Amptek), followed by a conventional nuclear electronic. The results obtained with this system for the direct detection of alpha particles from {sup 241}Am showed an excellent response stability with a high detection efficiency ({approx_equal} 100 %). The performance of this diode for alpha particle spectrometry was studied and it was prioritized the influence of the polarization voltage, the electronic noise, the temperature and the source-diode distance on the energy resolution. The results showed that the major contribution for the deterioration of this parameter is due to the diode dead layer thickness (1 {mu}m). However, even at room temperature, the energy resolution (FWHM = 18.8 keV) measured for the 5485.6 MeV alpha particles ({sup 241}Am) is comparable to those obtained with ordinary silicon barrier detectors frequently used for these particles spectrometry. (author)