We have determined for the first time the velocity distribution of neutrons from a solid H2 ultracold neutron (UCN) source. The spectrum rises sharply above 4.5m/s and has a maximum around 7m/s after transport in an 8m long guide. The number of neutrons in the UCN velocity range (< 7m/s) may be increased by a factor of two by placing the experiment 1m above the UCN source level. PACS. 29.25.Dz ...

The European Spallation Source (ESS) is one of Europe’s biggest and most prestigious science projects. ESS will be the world’s most powerful next generation neutron spallation source for research with neutrons, providing a unique tool for studies of the atomic structure and dynamics of matter. In this paper we use GEANT4 simulations to investigate the effects of spallation target material and i...

Plasma experiments conducted on the PF-1000 device generate the release of neutrons and ionizing radiation that are the source of immediate exposure to personnel. Neutron activation of materials in the research device and the surroundings is a source of ongoing radiation exposure to the same personnel. Having reported on personnel exposure from ionizing radiation and neutron activation, we now ...

I discuss the nature of the compact X-ray source inside the supernova remnant RCW 103. Several models, based on the accretion onto a compact object such as a neutron star or a black hole (isolated or binary), are analyzed. I show that it is more likely that the X-ray source is an accreting neutron star than an accreting black hole. I also argue that models of a binary system with an old accreti...

The fraction of delayed neutrons in a moderated beam from the enriched uranium, pulsed spallation source at the intense pulsed neutron source at Argonne National Laboratory has been measured and found to be 0.0283 for 450-MeV protons. Delayed neutrons produce a sample-dependent background in time-of-flight instruments . Because of the distribution of neutron wavelengths in the prompt pulse, the...

Fast and accurate identification of neutron sources is very important in nuclear nonproliferation and international safeguards applications. Commonly, the identification of neutron spectra relies on unfolding procedures, which requires the solution of an ill-posed problem. In this paper, we present a new application of an existing technique, which can be used for neutron source identification w...

In this research, cobalt and nickel sulfide nanoparticles (NPs) were grown on AlMCM-41 matrix by using ion exchange method. The prepared samples were irradiated by thermalized neutron that emitted from Am-Be source up to fluencies (7.9+E9n/cm2). After that, X-ray diffraction (XRD), UV-Vis spectroscopy, Fourier transform...

Background: The Poly-Allyl Diglycol Carbonate (PADC) detector is of particular interest for development of a fast neutron dosimeter. Fast neutrons interact with the constituents of the CR-39 detector and produce H, C and O recoils, as well as (n, α) reaction. These neutron- induced charged particles contribute towards the response of CR-39 detectors. Material and Methods: Electrochemical...

The development of a stochastic cellular automata model for low-density highly concentrated neutron sources is presented. The model was implemented for purely reflecting and absorbing media with no fission source. Results of numerical experiments for one benchmark case with the new model is compared to a traditional neutron diffusion calculation. Similarities and differences of the model with M...