Production Of Radioactive Isotopes Research Articles

Production of radioactive nuclides in inverse reaction kinematics

Efficient production of short-lived radioactive isotopes in inverse reaction kinematics is an important technique for various applications. It is particularly relevant when the isotope of interest is only a few nucleons away from a stable isotope. In this article production via charge exchange and stripping reactions in combination with a magnetic separator is explored. The relation between the separator transmission efficiency, the production yield, and the choice of beam energy is discussed. The results of some exploratory experiments will be presented.

Monte Carlo evaluation of the muon-induced background in the GERDA double beta decay experiment

The new generation of experiments searching for neutrinoless double beta decay is aiming at a background level of 10 - 3 counts / ( kg keV y ) or better at the respective Q-values. Cosmic ray muons can be a significant contribution due to a number of physics processes. The GERmanium Detector Array, GERDA, located at the Gran Sasso underground laboratory in Italy, uses germanium enriched in 76Ge as source and detector material. Germanium is submerged into liquid nitrogen or argon that acts as cooling medium and radiation shield simultaneously. A detailed G eant4-based Monte Carlo simulation was performed to calculate the photon and neutron fluxes induced by cosmic ray muons. The prompt background contributions from γ -ray and neutron interactions as well as the delayed contributions due to the production of radioactive isotopes within the setup are given. The background can be reduced to the desired level with the muon veto system incorporated in the GERDA design.

Radiation impact caused by activation of air from the future GSI accelerator facility fair

The Gesellschaft für Schwerionenforschung in Darmstadt is planning a new accelerator Facility for Antiproton and Ion Research (FAIR). Two future experimental areas are regarded to be the most decisive points concerning the activation of air. One is the area for the production of antiprotons. A second crucial experimental area is the so-called Super Fragment Separator. The production of radioactive isotopes in air is calculated using the residual nuclei option of the Monte Carlo program FLUKA. The results are compared with the data for the activation of air given by Sullivan and in IAEA report 283. The resulting effective dose is calculated using a program package from the German Federal Office for Radiation Protection, the Bundesamt für Stranlenschutz. The results demonstrate that a direct emission of the total radioactivity produced into the air will probably conflict with the limits of the German Radiation Protection Ordinance. Special measures have to be planned in order to reduce the amount of radioactivity released into the air.

Integrated target-ion source unit for on-line production of radioactive short-lived isotopes

A new version of integrated target-ion source unit (ionising target) has been developed for the on-line production of radioactive single-charged ions. The target is able to withstand temperatures up to 2500 °C and acts also as an ion source of the surface and laser ionisation. Off-line and on-line experiments with the ionising target, housing tantalum foils as a target material, have been carried out at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility. The off-line surface ionisation efficiency measured for stable atoms of Li, Rb and Cs was correspondingly 6% , 40% and 55% at the target temperature of 2000 °C and 3-10% for atoms of rare-earth elements Sm, Eu, Tm and Yb at a temperature of 2200 °C. The off-line measured values of the ionisation efficiency for stable Gd and Eu atoms by the laser beam ionisation inside the target were 1% and 7%, respectively. The radioactive beam intensities of neutron-deficient rare-earth nuclides from Eu to Lu produced by the integrated target-ion source unit have been measured at a temperature of 2500 °C. The results of the integrated target-ion source unit use for on-line laser resonance ionisation spectroscopy study of neutron-deficient Gd isotopes have been also presented.

Production of 11C-beam for particle therapy

A technical realization of a positron emitter 11C-beam (R.I.) as an accelerating beam has been studied at NIRS-HIMAC in order to apply it to heavy-ion therapy. The purpose of the present study is to show how to obtain a suitable beam intensity of a 11C-beam extracted from the HIMAC-synchrotron. Regarding this study, related developments include the production of radioactive isotopes (11C) by a cyclotron, gas-separation, gas-compression, gas-pulsing and ionization. Further, residue 11CO2-gas can be reproduced in the ionization process. As the result of a calculation, an order of 108 ppp of 11C6+ ions can be extracted from the HIMAC-synchrotron during 18min at 3.3s intervals with a 1ms beam pulse under the assumption of 1Ci of 11C-production. Details of the study are presented.

Recent applications of Synchrotrons in cancer therapy with Carbon Ions

As shown in Table 1, accelerators originally designed for scientific research have found a large number of industrial and medical applications. The main medical applications besides radioactive isotope production with cyclotrons are the electron linacs of a few MeV for radiotherapy of deep seated tumours. Every year in the developed countries about 40,000 people out of 1 million inhabitants are diagnosed as having cancer. About 50% of these patients are treated with radiation, mainly high energy photons produced by electron linacs. In 90% of the cases the electron beam is converted to Bremsstrahlung photons. These photon beams (called “X-rays” by medical doctors) have replaced the low energy X-rays and the 60Co gamma radiation because of a better depth-dose distribution (Fig. 1). Due to the fact that Compton-electrons go forward with a few centimetre range, the dose increases at the entrance (build-up effect) to a maximum value at 3-4 cm below the skin. This increase is followed by a shallow exponential decay for greater depth.

SU-FF-T-334: Activation Induced by Proton Interactions in a Multileaf Collimator in Proton Therapy

Purpose: The design of a computer-controlled multileaf collimator (MLC) for use in a proton radiotherapy beamline requires investigation of issues of neutron and radioactive isotope production due to activation, which result in an increase of dose to patients and personnel. Method and Materials: Materials such as tungsten (W), tungsten-copper (10%) alloy (WCu10), iron (Fe), low-carbon steel (LCS), medium-carbon steel (MCS), and brass have been studied to explore proton-induced radiation activation and generation of neutrons under proton bombardment of energy up to 250 MeV. Analysis was based on a wide variety of experimental and nuclear reaction simulation data. Neutrons generated will induce additional radioactivity in the MLC, in other materials in the treatment room, and will deposit undesirable dose in the patient. The size and cost of the materials need to be considered as well. Results: The probability of neutron production per 25 MeV energy interval of incident protons has been calculated for the selected materials as the proton stop. Furthermore, the probability for generation of radioactive products has been studied. The predominate radioactive nuclides with half-lives greater than 1 hour generated in three materials were as follows. For Fe: , and . For brass: . For W: . In terms of neutron production W has three times higher neutron multiplicity compared to Fe; however, W density is also 2.5 times as high to Fe and because of the higher atomic number may have better self-shielding properties. Conclusion: These results are being used to select an optimal material, not only for an MLC, but also for other patient devices used in proton therapy.

Calculations of high-power production target and beamdump for the GSI future Super-FRS for a fast extraction scheme at the FAIR Facility

A superconducting fragment separator (Super-FRS) is being designed for the production and separation of radioactive isotopes at the future FAIR (Facility for Antiprotons and Ion Research) facility at Darmstadt. This paper discusses various aspects and requirements for the high-power production target that will be used in the Super-FRS experiments. The production target must survive over an extended period of time as it will be used during the course of many experiments. The specific power deposited by the high intensity beam that will be generated at the future FAIR facility will be high enough to destroy the target in most of the cases as a result of a single shot from the new heavy ion synchrotrons SIS100/300. By using an appropriate beam intensity and focal spot parameters, the target would survive after being irradiated once. However, the heat should be dissipated efficiently before the same target area is irradiated again. We have considered a wheel shaped solid carbon target that rotates around its axis so that different areas of the target are irradiated successively. This allows for cooling of the beam heated region by thermal conduction before the same part of the target is irradiated a second time. Another attractive option is to use a liquid jet target at the Super-FRS. First calculations of a possible liquid lithium target are also presented in this paper. One of the advantages of using lithium as a target is that it will survive even if one uses a smaller focal spot, which has half the area of that used for a solid carbon target. This will significantly improve the isotope resolution.A similar problem associated with these experiments will be safe deposition of the beam energy in a beamdump after its interaction with the production target. We also present calculations to study the suitability of a proposed beamdump.

Radioactive beams at Texas A&M University: recent results and future plans

Over the last decade, the combination of the K500 superconducting cyclotron and the recoil spectrometer MARS have been used to generate a wide range of secondary radioactive ion beams. The secondary beams, which typically are produced via transfer reactions in inverse kinematics, have been used primarily for reaction measurements relevant to nuclear astrophysics and β -decay studies. Recently the BigSol spectrometer system has been completed and first measurements of secondary beam production with it have been carried out. Future plans for secondary beam production call for recommissioning the existing K150 (88) cyclotron as a source of high intensity primary beams which would be used with MARS and as a driver for the production of radioactive isotopes which would then be accelerated in the K500 cyclotron up to energies of 70 MeV/A for light nuclei.

Commissioning the TRIUMF/ISAC electron cyclotron resonance ion source for radioactive ion beams

A radiation hard 2.45 GHz ECR source has been installed in the ISAC target station. The ion source with its 8–60 kV extraction system is coupled to the radioactive isotope production target via a short transfer tube. The volatile radioactive isotopes produced by bombarding a target with a 500 MeV proton beam, are ionized and accelerated at the ECR source system. The source is reengineered to withstand a dose rate of 105 Gy/h from the activation of the target by the 500 MeV, 100 mA proton beam. The whole assembly is located beneath a 2 m thick steel shielding structure. Design aspect of the source and the initial results obtained during the commissioning at the ISAC terminal, as well as preliminary results obtained at the test stand are presented.

An accelerator-driven system for the destruction of nuclear waste

Progress in particle accelerator technology makes it possible to use a proton accelerator to produce energy and to destroy nuclear waste efficiently. The energy amplifier (EA) proposed by Carlo Rubbia and his group is a subcritical fast neutron system driven by a proton accelerator. It is particularly attractive for destroying, through fission, transuranic elements produced by presently operating nuclear reactors. The EA could also efficiently and at minimal cost transform long-lived fission fragments using the concept of adiabatic resonance crossing (ARC), recently tested at CERN with the TARC experiment. The ARC concept can be extended to several other domains of application (production of radioactive isotopes for medicine and industry, neutron research applications, etc.).

The 2.45 GHz ECR ion source for the first stage of the DRIBs project

The DRIBs (Dubna Radioactive Ion Beams) project suggests the use of two accelerator setups: the primary beam accelerator inducing reactions at a production target, and the secondary accelerator for radioactive nuclei transported into its ion source or directly into the center of an accelerator chamber. The first phase of the project assumes direct acceleration of radioactive light ions (such as 6He, 8He, 9Li, 11Be) at the U-400 cyclotron. The 2.45 GHz ECR ion source is dedicated to the production of single charged radioactive ion beams. Two versions of the magnetic structure composed of permanent magnet rings with different magnetization were designed for this ion source. Construction parts of the ion source and auxiliary equipment are described. The ion source was coupled with the system of radioactive isotope production. Preliminary results on the production of the 6He ion beam are presented.

A computer study of radionuclide production in high power accelerators for medical and industrial applications

Methods for radionuclide production calculation in a high power proton accelerator have been developed and applied to study production of 22 isotopes by high-energy protons and neutrons. These methods are readily applicable to accelerator, and reactor, environments other than the particular model we considered and to the production of other radioactive and stable isotopes. We have also developed methods for evaluating cross sections from a wide variety of sources into a single cross section set and have produced an evaluated library covering about a third of all natural elements. These methods also are applicable to an expanded set of reactions. A 684 page detailed report on this study, with 37 tables and 264 color figures is available on the Web at http://t2.lanl.gov/publications/publications.html, or, if not accessible, in hard copy from the authors.

An accelerator-driven system for the destruction of nuclear waste

Progress in particle accelerator technology makes it possible to use a proton accelerator to produce energy and to destroy nuclear waste efficiently. The Energy Amplifier (EA) proposed by Carlo Rubbia and his group is a subcritical fast neutron system driven by a proton accelerator. It is particularly attractive for destroying, through fission, transuranic elements produced by present nuclear reactors. The EA could also transform efficiently and at minimal cost long-lived fission fragments using the concept of Adiabatic Resonance Crossing (ARC) recently tested at CERN with the TARC experiment. The ARC concept can be extended to several other domains of application (production of radioactive isotopes for medicine and industry, neutron research applications, etc.).

Molybdenum and Zirconium Isotopes from a Supernova Neutron Burst

We analyze the nucleosynthesis implications of the recent discovery by M. J. Pellin and collaborators that two odd isotopes of molybdenum, 95Mo and 97Mo, are overabundant in type X SiC grains: X grains condensed within expanding supernova interiors. We find that a rapid release of neutrons (on a timescale of seconds) with fluence τ = 0.07-0.08 neutrons mbarn-1 produces the observed pattern by way of abundant production of progenitor radioactive Zr isotopes. This suggests that the condensing matter was in a supernova shell in which rapid burning was occurring at the time of ejection, probably owing to the passage of the shock wave from the core. Which shell, and the exact source of the neutrons, is still unknown, but we present a model based on the shock of an He shell.

Muon-induced production of radioactive isotopes in scintillation detectors

The production of radioactive isotopes in scintillation detectors by muons and their secondary shower particles has been studied experimentally at the SPS muon beam at CERN. This paper shows the results obtained in cross-section measurements on liquid scintillator targets, especially on 12C which is the most relevant target in these organic materials. Their energy dependence has been deduced from the cross-sections determined at two muon energies 100 and 190 GeV. Based on the measured cross-sections the muon-induced background rates for the forthcoming solar neutrino experiments BOREXINO and KAMLAND have been calculated for different energy regions that are relevant for solar neutrino physics.

Multinodal Treatment of Production, Decay, and Spreading of Radioactive Isotopes

The method of multinodal treatment of nuclear transition and spatial migration of radioactive materials in complex nuclear technological systems is described. The modeling of such processes is established in a very flexible way, enabling the user to investigate a wide range of problems related to nuclear safety, i.e., to predict the radioactive source term in normal operation and under accidental conditions of any nuclear plant. The migration of radioactive material can be connected either with the flow of reactor coolant or with any of the other physicochemical processes (filtration, deposition, etc.). On the basis of this method, a modular code system - TIBSO - has been developed.

Laser ion sources for on-line isotope separators

The application of resonant photoionisation using tuneable pulsed laser systems for the production of short-lived radioactive isotopes is discussed. The different ways the laser ionisation is implemented at existing on-line isotope separators is reviewed and the properties, limitations and expectations of the laser ion sources are highlighted.

Light Isotopes, Extinct Radioisotopes, and Gamma-Ray Lines from Low-Energy Cosmic-Ray Interactions

view Abstract Citations (135) References (47) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Light Isotopes, Extinct Radioisotopes, and Gamma-Ray Lines from Low-Energy Cosmic-Ray Interactions Ramaty, Reuven ; Kozlovsky, Benzion ; Lingenfelter, Richard E. Abstract We have carried out detailed calculations of gamma-ray line, light isotope, and extinct radioactive isotope production by low-energy cosmic rays for a broad range of accelerated particle abundances and energy spectra. We first apply these calculations to the gamma-ray line emission observed from the Orion molecular cloud complex. These gamma rays have provided the most direct evidence for the presence of large fluxes of low-energy cosmic rays in the Galaxy. Next we show that the bulk of the Galactic boron, beryllium, and 6Li could have been produced over the age of the Galaxy by interactions of low-energy cosmic rays having typical particle energies around 30 MeV nucleon-1 Such cosmic-ray interactions can account for the observed meteoritic 11B/10B which is higher than the isotopic ratio predicted by relativistic cosmic-ray interactions. Low- energy cosmic rays of similar energies could have also made a significant contribution to the production of 41Ca in meteoritic calcium-aluminum inclusions (CAIs) formed in the early solar system, provided that the cosmic-ray irradiation and CAl formation periods were essentially cotemporal. However, the production of significant amounts of 26Al by low-energy cosmic rays in the early solar system is unlikely because it would overproduce 9Be and 6Li. Publication: The Astrophysical Journal Pub Date: January 1996 DOI: 10.1086/176677 Bibcode: 1996ApJ...456..525R Keywords: ACCELERATION OF PARTICLES; ISM: COSMIC RAYS; GALAXY: ABUNDANCES; GAMMA RAYS: THEORY; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; ABUNDANCES; SOLAR SYSTEM: FORMATION; STARS: SUPERNOVAE: GENERAL full text sources ADS |

Gamma-rays from neutron stars

The number of Galactic neutron stars is significant, N ∼ 108–9, but radiation from their surfaces is hard to detect. The nearest isolated neutron stars could be as close as ∼ 10 pc (the estimate sensitively depends on assumptions about initial velocities), but would probably be too old, and thus too cold, for optical detections. Thatγ-ray emission is a useful alternative window for neutron star studies was revealed through observations of pulsedγ-ray emission from the Crab and Vela pulsars (e.g. Bignami 1987). A wealth of recentγ-ray observations of neutron stars is provided by sophisticated experiments aboard the COMPTON Gamma Ray Observatory (CGRO) and several other spacecraft. We summarize the current status of the Galactic population ofγ-ray pulsars. Gamma ray bursts are also believed to be associated with neutron stars. Although data from BATSE aboard CGRO have recently challenged the standard paradigm thatγ-ray bursts (GRBs) originate on or near neutron stars in the Galactic disk, the possibility of bursts from an extended Galactic halo of high velocity neutron stars is still under consideration. Furthermore, many cosmological scenarios also invoke neutron stars as the energy source. We thus include GRBs in this review. A subset of GRBs, the soft gamma repeaters, has recently been associated with Galactic supernova remnants. Their properties and counterparts are discussed. In addition, we briefly describeγ-ray emission from slowly accreting neutron stars, and theγ-ray line afterglow resulting from production of radioactive isotopes during their birth.