Determination of single neutron spectroscopic factor of doubly shell closed, neutron shell closed and neutron-rich nuclei through (d,p) reaction

The spectroscopic factor (SF) of doubly-magic nuclei, neutron shell closed and neutron-rich nuclei has been determined through ([Formula: see text], [Formula: see text]) reaction in the projectile energy range from 3 to 26[Formula: see text]MeV. The theoretical angular differential cross-sections of ([Formula: see text], [Formula: see text] reactions in scattering center-of-mass angles from [Formula: see text] to [Formula: see text] have been calculated using FRESCO and NRV-DWUCK5 codes. By comparing the theoretical angular differential cross-sections with available experimental angular differential cross-sections, the values of SF have been determined. The exponential increase of SF as a function of neutron separation energy normalized by spin of the recoil nuclei has been shown for the first time for doubly-magic nuclei. The similar type of trend has also been observed for neutron-rich as well as neutron shell closed nuclei as a function of neutron separation energy normalized by asymmetric factor of recoil nucleus. More experimental data are required to verify the trend predicted by this investigation.

THE 19/2- g-FACTOR IN 39K USING A TRANSIENT FIELD-FUSION REACTION TECHNIQUE

The magnetic moment of the 19/2- state in 39K has been measured by the transient field technique. The state was excited by the inverse reaction 12C(32S,pa)39K and the recoil nucleus traversed a thin Gd foil. Its absolute g-factor, g= 0.35(3), was obtained by an internal calibration, which makes use of the magnetic moment of the 15/2+ state in 41Ca also excited in the same reaction. The experimental result agrees well within shell model predictions.

Detail Engineering Design of Compact Neutron Generator to Support BNCT Facility in Indonesia

Boron Neutron Capture Therapy (BNCT) is a method of cancer therapy based on neutron radiation which has advantages over the other cancer therapy methods. It uses a stable isotope of 10B which will be an excited isotope of 11B when irradiated by thermal neutron. It immediately (in 10-12 s) breaks into α particle and a lithium recoil nucleus. The two secondary particles play important roles in killing cancer cells. They have a short range in tissue (5 µm and 9 µm respectively) which is less than the average dimension of a cell. This leads to the damage of cancer cell only but the normal cells remain safe. Thermal and epithermal neutrons play important roles in BNCT. From the beginning the neutron sources for BNCT are nuclear reactors which produce high intensity of thermal neutrons (En <0.5 eV), epithermal neutrons (0.5 eV< En < 10 keV) and fast neutrons (En > 10 keV). However, nuclear reactors are very expensive and too large to be used in hospitals. In addition, the operation of nuclear reactors is under restricted protocols related to safety and physical protection. A compact neutron generator is a good choice of neutron source for BNCT. The advantages of compact neutron generator are that the size is small and that the neutron yield is more than 109 ns-1 which satisfies the requirement recommended by IAEA. Additionally, the neutron energy is not so high that it requires a complicated neutron collimator, the operation is easy, and the public acceptance is higher than with nuclear reactors. Based on the requirements of epithermal neutron beam for BNCT facility, the detailed engineering design of compact neutron generator has been made.

Direct experimental detection of spatially localized clusters in nuclei on alpha-particle beams

Direct method for detecting intranuclear clusters of nuclear matter-clusters and determining their effective numbers was developed. The idea of the method is based on the functional coincidence of kinematics for light nuclei in the free state and clusters of the same mass within the nuclear volume. The reliability of the method is additionally confirmed by two experimental methods. The experiments were carried out at the Kazakhstan U-150M accelerator on a beam of [Formula: see text]-particles with energy of 29[Formula: see text]MeV. The first method consists in measuring the half-width of the elastic scattering peak from the angle and a comparison between the differential cross-sections of elastically scattered [Formula: see text] particles on free light nuclei and the differential cross-sections obtained by the authors on intranuclear multicluster. Using the second method, the correlation method, an experiment was performed to record the scattered [Formula: see text] particle on the 9Be nucleus-matrix and the recoil nucleus identical to it ([Formula: see text] particle). Thus, the kinematics of the [Formula: see text] 4He reaction, where 4He is an intranuclear [Formula: see text] cluster, indicates the presence of an intranuclear alpha cluster, which is further confirmed by the authors, an experimental measurement of intranuclear multicluster.

Heavy ion implantation combined with grazing incidence X-ray absorption spectroscopy (GIXAS): A new methodology for the characterisation of radiation damage in nuclear ceramics

An understanding of the effect of cumulative radiation damage on the integrity of ceramic wasteforms for plutonium and minor actinide disposition is key to the scientific case for safe disposal. Alpha recoil due to the decay of actinide species leads to the amorphisation of the initially crystalline host matrix, with potentially deleterious consequences such as macroscopic volume swelling and reduced resistance to aqueous dissolution. For the purpose of laboratory studies the effect of radiation damage can be simulated by various accelerated methodologies. The incorporation of short-lived actinide isotopes accurately reproduces damage arising from both alpha-particle and the heavy recoil nucleus, but requires access to specialist facilities. In contrast, fast ion implantation of inactive model ceramics effectively simulates the heavy recoil nucleus, leading to amorphisation of the host crystal lattice over very short time-scales. Although the resulting materials are easily handled, quantitative analysis of the resulting damaged surface layer has proved challenging.In this investigation, we have developed an experimental methodology for characterisation of radiation damaged structures in candidate ceramics for actinide disposition. Our approach involves implantation of bulk ceramic samples with 2 MeV Kr+ ions, to simulate heavy atom recoil; combined with grazing incidence X-ray absorption spectroscopy (GI-XAS) to characterise only the damaged surface layer. Here we present experimental GI-XAS data acquired at the Ti and Zr K-edges of ion implanted zirconolite, as a function of grazing angle, demonstrating that this technique can be successfully applied to characterise only the amorphised surface layer. Comparison of our findings with data from metamict natural analogues provide evidence that heavy ion implantation reproduces the amorphous structure arising from naturally accumulated radiation damage.

Towards Leap-Ahead Advances in Radiation Detection

Tension metastable fluid states offer unique potential for leap-ahead advancements in radiation detection. Such metastable fluid states can be attained using tailored resonant acoustics to result in acoustic tension metastable fluid detection (ATMFD) systems. ATMFD systems are under development at Purdue University. Radiation detection in ATMFD systems is based on the principle that incident nuclear particles interact with the dynamically tensioned fluid wherein the intermolecular bonds are sufficiently weakened such that even fundamental particles can be detected over eight orders of magnitude in energy with intrinsic efficiencies far above conventional detection systems. In the case of neutron-nuclei interactions the ionized recoil nucleus ejected from the target atom locally deposits its energy, effectively seeding the formation of vapor nuclei that grow from the sub-nano scale to visible scales such that it becomes possible to record the rate and timing of incoming radiation (neutrons, alphas, and photons). Nuclei form preferentially in the direction of incoming radiation. Imploding nuclei then result in shock waves that are readily possible to not only directly hear but also to monitor electronically at various points of the detector using time difference of arrival (TDOA) methods. In conjunction with hyperbolic positioning, the convolution of the resulting spatio-temporal information provides not just the evidence of rate of incident neutron radiation but also on directionality — a unique development in the field of radiation detection. The development of superior intrinsic-efficiency, low-cost, and rugged, ATMFD systems is being accomplished using a judicious combination of experimentation-cum-theoretical modeling. Modeling methodologies include Monte-Carlo based nuclear particle transport using MCNP5, and also complex multi-dimensional electromagneticcum-fluid-structural assessments with COMSOL’s Multi-physics simulation platform. Benchmarking and qualification studies have been conducted with Pu-based neutron-gamma sources with encouraging results. This paper summarizes the modeling-cum-experimental framework along with experimental evidence for the leap-ahead potential of the ATMFD system for transformation impact on the world of radiation detection.

Atomic Scale Modelling of the Primary Damage State of Irradiated UO2 Matrix

Large scale classical molecular dynamics simulations have been carried out to study the primary damage state due to a-decay self irradiation in UO2 matrix. Simulations of energetic displacement cascades up to the realistic energy of the recoil nucleus at 80 keV provide new informations on defect production, their spatial distribution and their clustering. The discrepancy with the classical linear theory NRT (Norton-Robinson-Torrens) law on the creation of the number of point defects is discussed. Study of cascade overlap sequence shows a saturation of the number of point defects created as the dose increases. Toward the end of the overlap sequence, large stable clusters of vacancies are observed. The values of athermal diffusion coefficients coming from the ballistic collisions and the additional point defects created during the cascades are estimated from these simulations to be, in all the cases, less than 10-26 m2/s. Finally, the influence of a grain boundary of type Sigma5 is analysed. It has been found that the energy of the cascades are dissipated along the interface and that most of the point defects are created at the grain boundary.