Search

Neutron-induced reactions are studied at the neutron time-of-flight facility n_TOF at CERN. The facility uses 6 similar to ns wide pulses of 20 GeV/c protons impinging on a lead spallation target. The large neutron energy range and the high instantaneous neutron flux combined with high resolution are among the key characteristics of the facility. After a first phase of data taking during the period 2001-2004, the facility has been refurbished with an upgraded spallation target and cooling system for a second phase of data taking which started in 2009. Since 2010, the experimental area at 185 m where the neutron beam arrives, has been modified into a worksector of type A, allowing the extension of the physics program to include neutron-induced reactions on radioactive isotopes

Intense neutron sources are essential for cargo inspection for a broad range of threats from explosives, to contraband, to nuclear materials and especially SNM (Special Nuclear Materials). To be effective over a wide range of cargo materials, in particular for hydrogenous cargo such as food, and to offer practical inspection times, the neutron source must be very strong, typically >1010 neutrons per second. Unfortunately there are currently no reasonably compact and economical neutron generators with the required intensities. The insufficiency and inadequacy of intense neutron sources are especially conspicuous in the ≤2.5 MeV range (low voltage (d,D) generator). This energy range is needed if the strong signature of prompt fission neutrons (≈3 per fission) is to be detected and discerned from the numerous source neutrons. The photonuclear reactions of x‐rays from commercial linacs in appropriate converters can provide ample intensities of neutrons. These converters have a very low (γ,n) energy threshold: 1.67 MeV for beryllium and 2.23 MeV for deuterium. The intense x‐ray beams provided by commercial x‐ray systems, more than compensate for the relatively low (γ,n) cross‐sections which are in the milli‐barn range. The choice of converter material, the geometrical shape, dimensions and location relative to the x‐ray source, determine the efficiency of the neutron conversion. For electron accelerators with less than 10 MeV, the preferred converters, Be and D2O, are also very good neutron moderators. Thus, while increasing the converters’ thickness leads to an increase in the overall neutron yield, this causes the softening of the neutron spectrum, which reduces the neutron penetration especially in hydrogenous cargos. Photoneutron sources can be optimized to meet specific needs such as maximum fission signals in various cargo materials of interest. Efficient photoneutron sources with different energy spectra were investigated. Conversion efficiency of more than 10‐4 neutron per 9 MeV electron yielding neutron intensities of more than 1011 n/s for commercial 100 μAmp electron accelerators has been modeled and designed. The simulation was validated in laboratory experiments using small Be and D2O converters.

This paper describes industrial charged particle beamline technologies and design approaches. Beamlines accommodate myriad constraints in the radioisotope production, electron beam processing, and ion implantation market segments, and some very strange yet interesting solutions result. In this paper, a detailed look at a particular injection beamline solution gives some sense of the complexity of research and development required, and the sophistication of the beamline solutions that are utilized. A brief review of beamline applications in each industrial segment follows.

Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium‐252 radioisotopic neutron sources in its PINS prompt gamma‐ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x‐ray output of the Thermo Scientific P385 deuterium‐deuterium neutron generator. X rays are a normal byproduct from neutron generators, but depending on their intensity and energy, x rays can interfere with gamma rays from the object under test, increase gamma‐spectrometer dead time, and reduce PGNAA system throughput. The P385 x‐ray energy spectrum was measured with a high‐purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x‐ray emission points, the generator also was rotated 60° between measurements. The scans show the primary source of x‐ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x‐ray count rate, and its x‐ray emission appears to be axially symmetric. A thin lead shield, 3.2 mm (1/8 inch) thick, reduced the 70‐keV generator x rays to negligible levels.

Active neutron interrogation has been used as a technique for the detection and identification of special nuclear material (SNM) for both proposed and field‐tested systems. Idaho National Laboratory (INL) has been studying this technique for systems ranging from small systems employing portable electronic neutron generators to larger systems employing linear accelerators as high‐energy photon sources for assessment of vehicles and cargo. In order to assess the feasibility of new systems, INL has undertaken a campaign of Monte Carlo simulations of the response of a variety of masses of SNM in multiple shielding configurations to a pulsed neutron source using the MCNPX code, with emphasis on the neutron and photon response of the system as a function of time after the initial neutron pulse. We present here some preliminary results from these calculations.

Japan Proton Accelerator Research Complex (J‐PARC) will be one of the highest intensity proton accelerators in the world aiming to realize 1 MW class of the beam power. The accelerator consists of a 400‐MeV linac, a 3‐GeV rapid‐cycling synchrotron (RCS) and a main ring synchrotron (MR), and the accelerated beam is applied to several experimental facilities. The linac, which is the injector for the RCS, has about 50 cavity modules to accelerate the beam up to 400 MeV. The acceleration field error in all of them should be within ±1% in amplitude and ±1 degree in phase because the momentum spread of the RCS injection beam is required to be within 0.1%. For the cavity field stabilization, a high‐stable optical signal distribution system is used as the RF reference, and sophisticated digital feedback and feed‐forward system is working well in the low level RF control system. Consequently the providing beam to the RCS is very stable, and the beam commissioning and the experiments of the application facilities h...

Barnes‐Jewish Hospital is on the verge of offering proton radiation therapy to its patients. Those treatments will be delivered from the first Monarch 250, a state‐of‐the‐art cyclotron produced by Still River Systems, Inc., Littleton, MA. The accelerator is the world’s first superconducting synchrocyclotron, with a field‐strength of 10 tesla, providing the smallest accelerator for high‐energy protons currently available. On May 14, 2010 it was announced that the first production unit had successfully extracted 250 MeV protons. That unit is scheduled for delivery to the Siteman Cancer Center, an NCI‐designated Comprehensive Cancer Center at Washington University School of Medicine. At a weight of 20 tons and with a diameter of less than 2 meters the compact cyclotron will be mounted on a gantry, another first for proton therapy systems. The single‐energy system includes 3 contoured scatterers and 14 different range modulators to provide 24 distinct beam delivery configurations. This allows proton fields up to 25 cm in diameter, with a maximum range from 5.5 to 32 cm and spread‐out‐Bragg‐peak extent up to 20 cm. Monte Carlo simulations have been run using MCNPX to simulate the clinical beam properties. Those calculations have been used to commission a commercial treatment planning system prior to final clinical measurements. MCNPX was also used to calculate the neutron background generated by protons in the scattering system and patient. Additional details of the facility and current status will be presented.

A comprehensive model has been developed to characterize and optimize the detection of Bremsstrahlung x‐ray induced fission signatures from nuclear materials hidden in cargo containers. An effective active interrogation system should not only induce a large number of fission events but also efficiently detect their signatures. The proposed scanning system utilizes a 9‐MV commercially available linear accelerator and the detection of strong fission signals i.e. delayed gamma rays and prompt neutrons. Because the scanning system is complex and the cargo containers are large and often highly attenuating, the simulation method segments the model into several physical steps, representing each change of radiation particle. Each approximation is carried‐out separately, resulting in a major reduction in computational time and a significant improvement in tally statistics. The model investigates the effect on the fission rate and detection rate by various cargo types, densities and distributions. Hydrogenous and metallic cargos, homogeneous and heterogeneous, as well as various locations of the nuclear material inside the cargo container were studied. We will show that for the photofission‐based interrogation system simulation, the final results are not only in good agreement with a full, single‐step simulation but also with experimental results, further validating the full‐system simulation.

The linear polarization of bremsstrahlung radiation emitted in collisions of spin‐polarized and unpolarized electrons with carbon and gold targets has been measured for an incident kinetic energy of 100 keV. We present preliminary results for the degree of linear polarization for incident unpolarized electrons as a function of bremsstrahlung photon energy.

Activity measurements on sediment samples for trapped‐charge geological dating using gamma‐ray spectroscopy are an important verification of the field‐site dose rate determination. Furthermore gamma‐ray spectroscopy can check if the natural decay series are in secular equilibrium which is a crucial assumption in such dating. Typically the activities of leading members of the Thorium and Uranium decay series are measured, which requires Germanium detectors with thin windows and good energy resolution in order to effectively detect the associated low energy gamma‐rays. Such equipment is not always readily available. The potential of conventional Germanium detectors with thick entrance window has been explored towards routine gamma‐ray spectroscopy of sediment samples using higher energy gamma‐rays. Alternative isotopes, such as Ac‐228 and Pb‐212 for the Thorium series, and Pa‐234m, Ra‐226 and Bi‐214 for the Uranium series, have been measured in order to determine the mass‐specific activity for the respective series and possibly provide a check of secular equilibrium. In addition to measurements of the K‐40 activity, with the alternative approach, the activities of both decay series can be accurately determined. The secular equilibrium condition may be tested for the Thorium series. Measurement accuracy for Pa‐234m is, however, not sufficient to permit also a reliable check of equilibrium for the Uranium series.

The material requirements for plasma‐facing components in a nuclear fusion reactor are some of the strictest and most challenging facing us today. These materials are simultaneously exposed to extreme heat loads (20 MW/m2 steady‐state, 1 GW/m2 in millisecond transients) and particle fluxes (>1024 m−2 s−1) while also undergoing high neutron irradiation (1018 neutrons/m2 s). At the Cambridge Laboratory of Accelerator Studies of Surfaces (CLASS), many of the most important issues in plasma‐surface interaction research, such as plasma‐driven material erosion and deposition, material transport and irradiation and hydrogenic retention are investigated with the use of a 1.7 MV tandem ion accelerator. Ion‐Beam Analysis (IBA) is used to investigate and quantify changes in materials due to plasma exposure and ion irradiation is used as a proxy for neutron irradiation to investigate plasma‐surface interactions for irradiated materials. This report will outline the capabilities and current research activities at CLASS.

A time‐of‐flight spectrometer with the BigSol superconducting solenoid at Texas A&M was used to investigate the possibility to produce heavy and superheavy nuclei by using two body collisions involving heavy projectiles and targets. The reaction 197Au+232Th at 7.5 AMeV is studied in this work. Preliminary results for the yields of heavy nuclei are presented.

225Ac has tremendous potential for the treatment of metastatic cancer due to the four alpha‐particles emitted during its decay to stable 209Bi. Additionally, it is one of the few alpha‐emitters being considered for clinical trials. The anticipated 225Ac demand for these trials is expected to far exceed the annual worldwide supply of approximately 1,000 mCi/yr. Consequently, the DOE Office of Science has funded investigations into accelerator‐based production of 225Ac. Existing 232Th(p,x)225Ac cross section data indicate that up to 480 mCi/day of 225Ac could be created by bombarding a thick target of natural thorium with 100 MeV protons at the Los Alamos Isotope Production Facility. To verify these predictions, experiments are underway at the Los Alamos Neutron Science Center to measure the 232Th(p,x)225Ac production cross sections for protons in the energy range 40–200 MeV, and at 800 MeV. For 800 MeV protons, preliminary results indicate that the 225Ac production cross section is 12.4±0.6 mb and the 225R...

Prompt fission neutrons continue to be examined as a signature for detecting the presence of fissionable material. This technique exploits the neutron energy limitations inherent with photonuclear emissions from non‐fissionable material, allowing prompt fission neutrons to be identified and engaged for detecting nuclear material. Prompt neutron signal measurements were acquired with bremsstrahlung endpoint energies of 6 MeV for 18 targets comprised of both fissionable and non‐fissionable material; delayed neutron measurements were also collected as a reference. The 238U target was also shielded with increasing thicknesses of lead or borated polyethylene to compare the resulting detection rates of the prompt and delayed fission neutron signals.

The High Energy Physics group of the University of Texas at Arlington has been developing gas electron multiplier detectors to use them as sensitive gap detectors in digital hadron calorimeters for the International Linear Collider, a future high energy particle accelerator. For this purpose, we constructed numerous GEM detectors that employ double GEM layers. In this study, two kinds of prototype GEM detectors were tested; one with 28×28 cm2 active area double GEM structure with a 3 mm drift gap, a 1 mm transfer gap and a 1 mm induction gap and the other with two 3×3 cm2 GEM foils in the amplifier stage with a 5 mm drift gap, a 2 mm transfer gap and a 1 mm induction gap. The detectors’ characteristics from exposure to high‐energy charged particles and other radiations were measured using cosmic rays and 55Fe radioactive source. From the 55Fe tests, we observed two well separated characteristic X‐ray emission peaks and confirmed the detectors’ functionality. We also measured chamber gains to be over 6000 ...

Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}

NBS‐1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257×106 n/s1,2,3 with an uncertainty of 0.85% (k = 1). Neutron emission‐rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS‐1. The neutron output of the generator was determined with an uncertainty of about 7% (k = 1). The 15‐hour half‐life of one of the reactions used also makes possible off‐site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

The Canadian Centre for Accelerator Mass Spectrometry (AMS) at the University of Ottawa will be equipped with a new, 3 MV tandem accelerator with peripheral equipment for the analysis of elements ranging from tritium to the actinides. This facility, along with a wide array of support instrumentation recently funded by the Canada Foundation for Innovation, will be located in a new science building on the downtown campus of the University of Ottawa. In addition to providing the standard AMS measurements on 14C, 10Be, 26Al, 36Cl and 129I for earth, environmental, cultural and biomedical sciences, this facility will incorporate the new technologies of anion isobar separation at low energies using RFQ chemical reaction cells for 36Cl and new heavy element applications, integrated sample combustion and gas ion source for biomedical and environmental 14C analysis and the use of novel target matrices for expanding the range of applicable elements and simplifying sample preparation, all currently being developed a...

We present preliminary results of photo‐fission measurements of uranium isotopes with the quasi‐monoenergetic gamma‐ray source, HIGS. The measurements were performed to search for photo‐fission resonances. We discuss potential applications to use photo‐fission resonances to identify special nuclear material in cargo containers. We discuss the importance of quasi‐monoenergetic gamma‐ray sources for this kind of application.

A compact mono‐energetic gamma source is being developed to replace the radiological sources used in radiotherapy and other medical instruments. The electronic gamma source utilizes low‐energy nuclear reactions to generate gammas in the 0.5 to 1.0 MeV energy range. Independent control of the ion current and energy is achieved by decoupling the RF‐driven ion source and pyroelectric crystal‐based acceleration systems The ions are accelerated to voltages above 100 keV and bombard a reaction target to produce gammas. Thermal management of the pyroelectric crystal‐based accelerator is achieved by convective dielectric fluid flow around the crystal. This approach provides better temperature uniformity in the crystal and higher dielectric strength for suppressing voltage breakdown and enabling faster thermal cycling rates.

We present an analytical model for calculation of double scattering in elastic recoil detection measurements. Only events involving the beam particle and the recoil are considered, i.e. 1) an ion scatters off a target element and then produces a recoil, and 2) an ion produces a recoil which then scatters off a target element. Events involving intermediate recoils are not considered, i.e. when the primary ion produces a recoil which then produces a second recoil. If the recoil element is also present in the stopping foil, recoil events in the stopping foil are also calculated. We included the model in the standard code for IBA data analysis NDF, and applied it to the measurement of hydrogen in Si.

Kinematic focusing of an emitted fairly mono‐energetic neutron beam by the use of inverse‐kinematic reactions, i.e. where the projectile mass is greater than the target atom’s mass, can provide for the utilization of a significant fraction of the fast neutron yield and also provide for a safer radiation environment. We examine the merit of various neutron production reactions and consider the practicalities of producing the primary beam using the suitable accelerator technologies. Preliminary progress at the NSWC‐Carderock Positive Ion Accelerator Facility is described. Possible important applications for this type of neutron‐based system can be both advanced medical imaging techniques and active “stand‐off” interrogation of contraband items.

Development of two innovative linacs is discussed. (1) High‐efficiency normal‐conducting accelerating structures for ions with beam velocities in the range of a few percent of the speed of light. Two existing accelerator technologies—the H‐mode resonator cavities and transverse beam focusing by permanent‐magnet quadrupoles (PMQ)—are merged to create efficient structures for light‐ion beams of considerable currents. The inter‐digital H‐mode accelerator with PMQ focusing (IH‐PMQ) has the shunt impedance 10–20 times higher than the standard drift‐tube linac. Results of the combined 3‐D modeling for an IH‐PMQ accelerator tank—electromagnetic computations, beam‐dynamics simulations, and thermal‐stress analysis—are presented. H‐PMQ structures following a short RFQ accelerator can be used in the front end of ion linacs or in stand‐alone applications like a compact mobile deuteron‐beam accelerator up to a few MeV. (2) A large‐acceptance high‐gradient linac for accelerating low‐energy muons in a strong solenoidal ...

J‐PARC accelerator research complex, consisting of LINAC, RCS and MR synchrotron, has successfully produced neutron, muons, kaons, and neutrinos by steady commissioning since November 2006. There are three experimental facilities, and for nuclear and particle physics, nine experiments are approved in a hadron physics facility, and one experiment is approved in a neutrino physics facility. Those experiments and status of J‐PARC are described in this paper.

The use of octupole elements was originally suggested [1] to transform the transverse Gaussian distribution of a charged particle beam into a uniform beam distribution having rectangular cross section. The first experimental realization of this concept was materialized at the Radiation Effects Facility (REF) of the Brookhaven National Laboratory (BNL) [2] where the transverse Gaussian distribution of a 200 MeV H− beam was transformed into a rectangular uniform distribution. Later, the beam line of the NASA Space Radiation Laboratory (NSRL) facility [3,4] built at BNL, was specifically designed to generate uniform beam distributions with rectangular cross sections, in both, the horizontal and vertical directions, at the location of the target. The NSRL facility generates uniform beam distributions of various nuclear species, which may vary in energy, and also vary in size of the uniform beam distribution. We will present an overview of the method to generate uniform beam distributions, show some results fr...

The EURITRACK portal makes use of the tagged neutron technique to inspect suspect regions of cargo containers identified in preliminary x‐ray inspections. The portal has been in operation at the Rijeka seaport during the last three years. The performances of sub‐systems, with particular interest on the sealed tube neutron generator, is presented.

Undergraduate students at the University of Dallas (UD) have investigated elastic and inelastic neutron scattering cross sections on structural materials important for criticality considerations in nuclear fission processes. Neutrons scattered off of 23Na and NatFe were detected using neutron time‐of‐flight techniques at the University of Kentucky Low‐Energy Nuclear Accelerator Facility. These measurements are part of an effort to increase the efficiency of power generation from existing fission reactors in the US and in the design of new fission systems. Students have learned the basics of how to operate the Model CN Van de Graaff generator at the laboratory, setup detectors and electronics, use data acquisition systems, and they are currently analyzing the angular dependence of the scattered neutrons for incident neutron energies of 3.57 and 3.80 MeV. Most students participating in the project will use the research experience as the material for their undergraduate research thesis required for all Bache...

The Nuclear Science and Engineering Research Center (NSERC), a Defense Threat Reduction Agency (DTRA) office located at the United States Military Academy (USMA), sponsors and manages cadet and faculty research in support of DTRA objectives. Cadets in the Department of Physics and Nuclear Engineering at USMA are using pyroelectric crystals to ionize and accelerate residual gas trapped inside a vacuum system. A system using two lithium tantalate crystals with associated diagnostics was designed and is now operational. X‐ray energies of approximately 150 keV have been achieved. Future work will focus on developing a portable neutron generator using the D‐D nuclear fusion process.

Collimators are usually needed to image sources emitting X‐rays that cannot be focused. Alternately, one may employ a Compton Camera (CC) and measure the direction of the incident X‐ray by letting it interact with a thin solid, liquid or gaseous material (Tracker) and determine the scattering angle. With respect to collimated cameras, CCs allow higher gamma‐ray efficiency in spite of lighter geometry, and may feature comparable spatial resolution. CCs are better when the X‐ray energy is high and small setups are required. We review current applications of CCs to Gamma Ray Astronomy and Biomedical systems stressing advantages and drawbacks. As an example, we focus on a particular CC we are developing, which is designed to image small animals administered with marked pharmaceuticals, and assess the bio‐distribution and targeting capability of these latter. This camera has to address some requirements: relatively high activity of the imaged objects; detection of gamma‐rays of different energies that may range from 140 keV (Tc99m) to 511 keV; presence of gamma and beta radiation with energies up to 2 MeV in case of 188Re. The camera consists of a thin position‐sensitive Silicon Drift Detector as Tracker, and a further downstream position‐sensitive system employing scintillating crystals and a multi‐anode photo‐multiplier (Calorimeter). The choice of crystal, pixel size, and detector geometry has been driven by measurements and simulations with the tracking code GEANT4. Spatial resolution, efficiency and scope are discussed.

The capability of hadron colliders has increased to where it will soon be possible to collide protons at center of mass energies of 14 TeV with the advent of the LHC. With increasing collision energy, calorimeters become ever more essential components of a detector, and collaborations often choose very different technologies to meet their goals. From the perspective of a high energy particle and nuclear physicist, a survey is presented of the differences in design considerations and actual performance of the wide variety of calorimeters used in modern hadron colliders such as the Tevatron, RHIC, and LHC. The lessons learned and some ideas for future development of calorimetry will also be discussed.

A sensitive method to determine the spin of neutron resonances is introduced based on the statistical pattern recognition technique. The new method was used to assign the spins of s‐wave resonances in 155Gd. The experimental neutron capture data for these nuclei were measured with the DANCE (Detector for Advanced Neutron Capture Experiment) calorimeter at the Los Alamos Neutron Science Center. The highly segmented calorimeter provided detailed multiplicity distributions of the capture γ‐rays. Using this information, the spins of the neutron capture resonances were determined. With these new spin assignments, level spacings are determined separately for s‐wave resonances with Jπ = 1− and 2−.

Sumitomo Heavy Industries, Ltd. (SHI) has developed a new pencil beam scanning system (PBS) for proton therapy in collaboration with National Cancer Center Hospital East (NCCHE). Taking advantage of the continuous beam from the cyclotron P235, the line scanning method is employed in order to realize continuous irradiation with high dose rate. 3D uniform and sphere field was irradiated and compared with the simulation.

K = 100 Separated Sector Cyclotron was designed in conceptual for the ISOL driver. It has 4 separated sector magnets. Two SF cyclotrons will be used as the injectors for separated sector cyclotron. RF frequency is 70 MHz, 4th harmonics. We have designed sector magnet without trim and harmonic coils. Minimum radius of the magnet is 55 cm and maximum radius is 1.8 m. Designed magnets were calculated and simulated by OPERA 3D (TOSCA) code. Ion beam dynamics calculations have been done using particle studio code to prove the focusing properties of the designed magnets.

Effective cargo inspection systems for nuclear material detection require good penetration by the interrogating radiation, generation of a sufficient number of fissions, and strong and penetrating detection signatures. Inspection systems need also to be sensitive over a wide range of cargo types and densities encountered in daily commerce. Thus they need to be effective with highly hydrogenous cargo, where neutron attenuation is a major limitation, as well as with dense metallic cargo, where x‐ray penetration is low. A system that interrogates cargo with both neutrons and x‐rays can, in principle, achieve high performance over the widest range of cargos. Moreover, utilizing strong prompt‐neutron (∼3 per fission) and delayed‐gamma ray (∼7 per fission) signatures further strengthens the detection sensitivity across all cargo types. The complementary nature of x‐rays and neutrons, used as both probing radiation and detection signatures, alleviates the need to employ exceedingly strong sources, which would ot...

Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio‐isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 [1] and the All field calculations had been performed by OPERA‐3D TOSCA [2]. The self‐made beam dynamics program OPTICY [3] is used for making isochronous field and other calculations.

Experiments of interest in Atomic Physics require production of well‐defined low‐energy positron beams through a moderation process of high‐energy positrons, which can be produced by either the use of a radioactive source or by accelerator based pair production process. Tungsten is one of the most commonly used moderator materials because of its reasonable efficiency, high work function and relatively low cost. In this work we present different methods to produce tungsten‐based candidate moderators in a variety of shapes. We also present results from characterizing these candidate moderators by ion beam analysis and microscopy techniques.

An array is designed for 24 Compton suppressed clover detectors. Recent results from the array will be presented which highlights the structure of nuclei in A ∼ 110 and 130 region and investigation of different reactions dynamics. The perspectives offered by the forthcoming operation of the clover array coupled to a new digital data acquisition system are also discussed briefly.

The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of the HRIBF is the production of high quality beams of shortlived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron‐rich fission fragment beams post‐accelerated to energies above the Coulomb barrier for nuclear reactions. HRIBF produces RIBs by the isotope separator on‐line (ISOL) technique using a particle accelerator system that consists of the Oak Ridge Isochronous Cyclotron (ORIC) driver accelerator, one of the two Injectors for Radioactive Ion Species (IRIS1 or IRIS2) production systems, and the 25‐MV tandem electrostatic accelerator that is used for RIB post‐acceleration. ORIC provides a light ion beam (proton, deuteron, or alpha) which is directed onto a thick target mounted in a target‐ion source (TIS) assembly located on IRIS1 or IRIS2. Radioactive atoms that diffuse from the target material are ionized, accelerated, mass selected, and transported to the tandem accelerator where they are further accelerated to energies suitable for nuclear physics research. RIBs are transported through a beam line system to various experimental end stations including the Recoil Mass Spectrometer (RMS) for nuclear structure research, and the Daresbury Recoil Separator (DRS) for nuclear astrophysics research. HRIBF also includes two off‐line ion source test facilities, one low‐power on‐line ISOL test facility (OLTF), and one high‐power on‐line ISOL test facility (HPTL). This paper provides an overview and status update of HRIBF, describes the recently completed $4.7M IRIS2 addition and incorporation of laser systems for beam production and purification, and discusses a proposed replacement of the ORIC driver accelerator.

The perennial presence of dust in high‐temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next‐generation steady‐state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Although much effort has been devoted to getting rid of the dust nuisance, there are instances where a controlled use of dust can be beneficial. We have recognized a number of dust‐accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust‐plasma interactions, and more recently in edge localized mode (ELM)’s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas‐drag, and plasma‐drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

A Cuttler‐Shalev (C‐S) 3He proportional counter has been used to measure the energy spectrum of neutrons from a portable deuterium‐deuterium electronic neutron generator. To improve the analysis of results from the C‐S detector digital pulse shape analysis techniques have been used to eliminate neutron recoil artifacts in the recorded data. Data was collected using a 8‐GHz, 10‐bit waveform digitizer with its full scale corresponding to approximately 6‐MeV neutrons. The measurements were made with the detector axis perpendicular to the direction of ions in the ENG in a plane 0.5‐m to the side of the ENG, measuring neutrons emitted at an angle from 87.3° to 92.7° with respect to the path of ions in the ENG. The system demonstrated an energy resolution of approximately 0.040 MeV for the thermal peak and approximately 0.13 MeV at the DD neutron energy. In order to achieve the ultimate resolution capable with this type of detector it is clear that a higher‐precision digitizer will be needed.

In 1932, Cockcroft and Walton showed that (p,α) reactions with lithium were possible at energies near 100 keV. We report an undergraduate laboratory experiment with 90 keV protons colliding with a thick lithium target. The experiment allows students to observe the products of two reactions, to determine the product masses, and to learn techniques for deconvolving experimental spectra profiles.

Gas Electron Multiplier (GEM) detector is a gas detector with high gain and high efficiency. These detectors utilize chemically perforated 65μm thin copper clad Kapton (a polymer) foils. Given its potential for detecting X-rays and other radiation, GEM detectors can be used in an environment with high radioactivity. Kapton foils are manufactured by Du Pont Inc. and claimed to be radioactive resistant. To confirm whether the GEM detector performance is affected by radiation exposure, GEM foils are irradiated at the gamma irradiation facility for sterilization. Electronic signal variation of irradiated small GEM detectors exposed to the level of 10kGy, 100kGy, 1,000kGy and 10,000kGy were measured. As a result, it is confirmed that the peak shapes are distorted, and the detector gain changed compared to those of un- irradiated small GEM detectors. In particular, the detector with 10,000kGy irradiation appears to have the biggest peak distortion and increased detector gain. It was also verified that some additional electrons contributing to the electronic signal of irradiated small GEM detectors come from the radiation-induced free radicals in Kapton film of the irradiated GEM foils via the tests with and without a radioactive source. The mechanism of these changes cannot be explained in detail at present, and thus require further study.

An automatic, nuclear‐reaction‐based, few‐view transmission radiography method and system concept is presented, that will simultaneously detect small, operationally‐relevant quantities of chemical explosives and special nuclear materials (SNM) in objects up to the size of LD‐3 aviation containers. Detection of all threat materials is performed via the 11B(d,n+γ) reaction on thick, isotopically‐enriched targets; SNM are primarily detected via Dual Discrete‐Energy Radiography (DDER), using 15.11 MeV and 4.43 MeV 12C γ‐rays, whereas explosives are primarily detected via Fast Neutron Resonance Radiography (FNRR), employing the broad‐energy neutron spectra produced in a thick 11B‐target. To achieve a reasonable throughput of ∼20 containers per hour, ns‐pulsed deuteron beam of the order of 0.5 mA intensity at energies of 5–7 MeV is required. As a first step towards optimizing parameters and sensitivities of an operational system, the 0° spectra and yields of both γ‐rays and neutrons in this reaction have been m...

Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications in a wide energy range from sub thermal energies up to 200 MeV. Parallel‐plate ionization chambers are used to measure fission cross sections ratios relative to the 235U standard while incident neutron energies are determined using the time‐of‐flight method. Recent measurements include the 233,238U, 239–242Pu and 243Am neutron‐induced fission cross sections. Obtained data are presented in comparison with existing evaluations and previous data.

During the past ten years the present collaboration has carried out several experiments related with the study of radioactive nuclei. One of the topics in which we have centered our research, is the scattering of halo nuclei at energies around the Coulomb barrier. As part of this study, we present in this work a review of the results obtained from the scattering of 6He, 11Be and 11Li. The presence of a >halo> in these exotic nuclei is found to have a striking effect on the dynamics of these reactions, making their study an interesting experimental problem and a challenge for existing reaction theories.

The array of microbeam cell-irradiation systems, available to users at the Radiological Research Accelerator Facility (RARAF), Center for Radiological Research, Columbia University, is expanding. The HVE 5MV Singletron particle accelerator at the facility provides particles to two focused ion microbeam lines: the sub-micron microbeam II and the permanent magnetic microbeam (PMM). Both the electrostatic quadrupole lenses on the microbeam II system and the magnetic quadrupole lenses on the PMM system are arranged as compound lenses consisting of two quadrupole triplets with "Russian" symmetry. Also, the RARAF accelerator is a source for a proton-induced x-ray microbeam (undergoing testing) and is projected to supply protons to a neutron microbeam based on the (7)Li(p, n)(7)Be nuclear reaction (under development). Leveraging from the multiphoton microscope technology integrated within the microbeam II endstation, a UV microspot irradiator - based on multiphoton excitation - is available for facility users. Highlights from radiation-biology demonstrations on single living mammalian cells are included in this review of microbeam systems for cell irradiation at RARAF.

Photon Activation Analysis (PAA) of environmental, archaeological and industrial samples requires extensive data analysis that is susceptible to error. For the purpose of saving time, manpower and minimizing error, a computer program was designed, built and implemented using SQL, Access 2007 and asp.net technology to automate this process. Based on the peak information of the spectrum and assisted by its PAA library, the program automatically identifies elements in the samples and calculates their concentrations and respective uncertainties. The software also could be operated in browser/server mode, which gives the possibility to use it anywhere the internet is accessible. By switching the nuclide library and the related formula behind, the new software can be easily expanded to neutron activation analysis (NAA), charged particle activation analysis (CPAA) or proton-induced X-ray emission (PIXE). Implementation of this would standardize the analysis of nuclear activation data. Results from this software were compared to standard PAA analysis with excellent agreement. With minimum input from the user, the software has proven to be fast, user- friendly and reliable.

The neutron exposure accelerator system for biological effect experiments (NASBEE) was developed to study biological effects of fast neutrons. We have characterized the NASBEE neutron beams with neutron energy spectrum, absorbed dose energy distributions, and space distributions. The neutron energy spectrum shows 2.3 MeV as mean energy and 3.0 MeV as kerma of tissue‐equivalent‐plastic (A150) weighted mean energy, and the maximum neutron energy was determined to be 9 MeV. Neutron absorbed doses occupy 82% of the NASBEE neutron beam. NASBEE has been used to learn some of the outcomes of the biological effects of fast neutrons.

In this paper we will discuss experiments performed using an accelerated ion beam incident on selected targets. Some of these were: 1) Measuring Rutherford scattering and/or non‐Rutherford nature of scattering as a function of scattering angle, energy of the ion beam and atomic number 2) Verifying theoretical prediction of the kinematical scattering factor by measuring the scattered ion energy 3) Particle Induced X‐ray emission (PIXE) and/or Rutherford scattering to determine the elemental thickness and test the theoretical prediction for the x‐ray production cross sections. 4) Determination of the mass absorption coefficient of lead using gamma ray spectroscopy 5) Nuclear reaction studies (proton on lithium fluoride) using sodium iodide detector 6) Applying X‐ray fluorescence to determine elemental composition.

Using our large collection of experimental stopping power data, we compare these data with various theories and stopping codes, in order to judge the quality of both data and theories. We discuss the influence of the state of aggregation of the target upon stopping power, and the importance of choosing the best value of the ionization potential of water for medical applications.