The calibration procedure of silver activation detectors using a mono energetic neutron source with 5MeV beam energy at FRS of JAERI (Japan Atomic Energy Research Institute) is described in this paper. These detectors are fabricated for measuring fusion neutron burst emitted of z-pinch and plasma focus devices in ASRL (the Atomic Science Research Laboratory).

Investigation of Hydrocarbon reservoir is important, so it is essential to predict and explore them precisely. One of the methods is well logging, which can transfer the probe or tool in the well to measure one or more characteristics. Nuclear well logging includes radioisotope source and at least one detector. In this work, emission direction of neutrons from the 241Am-Be neutron source toward the calcite formation has been investigated using MCNPX 2. 6 to obtain the best precision in determining the liquid porosity. The results show that emission direction of 20 in degree with the resolution porosity of 3% in counts is recorded in detectors; as well; there is no decrease in depth penetration, providing speed of tools.

Since Parts of Our Country are Situated in iodine deficient regions, the measurement of the element in foodstuffs is the first step in recognition and treatment of some diseases such as guatre. The measurement of some trace elements such as iodine by convention analytical methods is not practical (1). In this research, to achieve the lower detection limit, the method of neutron activation analysis was used. The presence of some elements such as aluminum, manganese, chlorine and sodium with high neutron capturing cross section of thermal neutron has the main interfering effect in iodine measurement. The epithermal neutrons were then used to reduce the interfering effect. The iodine content of the studied samples was different ,Where the North Hassani sample possesses the highest content of 493 ± 187.6PPm Lenjan sample has the minimal amount of <30ppm.  

neutron detection techniques are widely studied in many articles. Most of this research requires a lot of electronic equipment. In this study, using the Thick Gas electron multiplier (THGEM) detector, a new method for neutron detection is proposed to reduce electronic equipment. In the neutron detection system, the converter material is used for converting neutrons to protons that are directed to the THGEM detector. By filling the detector space with noble gas and applying special voltage, THGEM enters to Self-Quenched Streamer (SQS) mode for protons detection. All these steps are examined by simulation, then the detection system is made and is examined in the laboratory. Finally, the simulation results and laboratory results are compared.    The results show that the 1 mm Plexiglas layer is suitable for converting neutrons to protons. The suitable distance between the converter layer and the THGEM detector is 3 cm. Also, the SQS mode happens in the most number of THGEM holes when the THGEM voltage is 980 volt. Investigating an approach to neutron detection by placing THGEM in SQS mode can be useful because, firstly, placing the THGEM detector in SQS mode simplifies electrical circuits and secondly, with this proposed detection system; it is possible to design detectors with different dimensions for neutrons.

Background: A Boron neutron Capture Therapy (BNCT) facility, based on a DT neutron generator, with the final goal to find out a potential, alternative, solution to existing BNCT treatment facilities which are based on nuclear reactors is examined. Materials and Methods: With the aim of the MCNP4B Monte Carlo code different beam‐shaping assembly (BSA) configurations were considered. Lead was selected as reflector material while CF2, D2O, Fluental, PbF4, PbF2, BiF3, BiF5, MgF2, Al2O3, AlF3, TiF3, BeD2, CaF2 and 7LiF were examined as spectrum shitiers. In order to improve the quality of the beam titanium, nickel‐60, iron and titanium alloy (Ti6Al14V) were simulated as fast neutrons filters while lead and bismuth were considered as gamma filters.Results: An extensive set of calculations performed with MCNP4B Monte Carlo code have shown that the combination of 7LiF which accommodates a conic part made of D2O, then followed by a TiF3 layer is the optimum moderator design. The use of three different materials for further reduction of fast neutrons, thermal neutrons and gamma rays is necessary.60Ni, Cd and Bi were chosen respectively for these purposes. The epithermal neutron flux obtained at the beam exit window turned out to be 3.94×109 n cm‐2 s‐1 while fulfilling all the recommended IAEA in‐air Figure Of Merit (FOM) criteria. The assessment of the dose profiles in head phantom and the in‐phantom FOM are also presented.Conclusion: The proposed assembly configuration may provide an atiractive option for centers wishing to install a BNCT facility.

In this study, calibration process was carried out for deigned new CR-39 nuclear track detector for protons, neutrons and alpha particles separately under the same etching condition. In order to aim this purpose, americium-beryllium standard source (241Am-Be) and Plexiglas phantom for neutron irradiation, brass collimators and americium standard source (241Am) for alpha irradiation and the accelerator and Van de Graff accelerator for proton irradiation were employed. Sodium hydroxide solution 6. 25N at the temperature of 85 ° C was used for CR-39 etching. Considering obtained results, different detection shields were designed to distinguish between fast neutron particles, thermal neutrons, albedo neutrons, protons and alpha in mixed radiation fields. Moreover, both the contribution of each particle and the ability of the designed detector to discriminate energy of charged particles were found.