scholarly journals Neutron Beam Characterization at the Athens Tandem Accelerator NCSR “Demokritos”

2019 ◽  
Vol 23 ◽  
pp. 34 ◽  
Author(s):  
R. Vlastou ◽  
D. Sigalas ◽  
A. Kalamara ◽  
M. Kokkoris ◽  
M. Anastasiou ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Energy Spectrum ◽  
Activation Analysis ◽  
Neutron Beam ◽  
Flux Variation ◽  
Tandem Accelerator ◽  
Analysis Technique ◽  
Foil Activation ◽  
Beam Characterization ◽  
Reference Reaction

A new Ti-tritiated target of 373 GBq activity has been installed at the 5.5MV tandem T11/25 Accelerator of NCSR "Demokritos", to produce neutrons in the energy range ~15-21 MeV by means of the 3H(d,n)4He reaction. The flux variation of the neutron beam is monitored with a BF3 detector, while the absolute flux is obtained with respect to reference reactions, such as the 27Al(n,a) reference reaction. In absence of time-of-flight capabilities, the energy spectrum of the neutron beam has been investigated by means of Monte Carlo simulations as well as by the Multiple Foil Activation Analysis technique, using reactions with different energy thresholds. The experimental results have been compared with the simulated ones in order to validate the simulations

scholarly journals Neutron induced reactions at the Athens Tandem accelerator NCSR "Demokritos"

2019 ◽  
Vol 14 ◽  
pp. 1
Author(s):  
R. Vlastou ◽  
C. T. Papadopoulos ◽  
M. Kokkoris ◽  
G. Perdikakis ◽  
S. Galanopoulos ◽  
...  
Keyword(s):  
Energy Range ◽  
Energy Dependence ◽  
Neutron Beam ◽  
Neutron Fluence ◽  
Liquid Scintillator ◽  
Activation Technique ◽  
Flux Variation ◽  
Tandem Accelerator ◽  
Foil Activation ◽  
Neutron Facility

The neutron facility at the 5.5 MV Tandem Tll/25 accelerator of NCSR "Demokritos" has been used to produce monoenergetic neutron beams in the energy range 120-650 keV and 4-11.5 MeV via the 7Li(p,n) and 2H(d,n) reactions, respectively. The flux variation of the neutron beam was monitored by using a BF3 detector, while an investigation of the energy dependence of the neutron fluence has been carried out with a liquid scintillator BC501A detector as well as with the multiple foil activation technique. The 232Th(n,2n)231Th and 241Am(n,2n)240Am as well as (n,2n), (n,p) and (η,α) reactions on natural Ge and Hf isotopes, have been investigated from threshold up to 11.5 MeV, by using the activation method.

scholarly journals Measurement of the 241Am(n,2n)240Am cross section at 17.5 MeV

2019 ◽  
Vol 21 ◽  
pp. 160
Author(s):  
A. Kalamara ◽  
R. Vlastou ◽  
M. Diakaki ◽  
M. Kokkoris ◽  
M. Anastasiou ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Beam ◽  
Cross Sections ◽  
Reaction Cross ◽  
Activation Technique ◽  
Tandem Accelerator ◽  
Hpge Detectors ◽  
Reaction Cross Sections ◽  
Reference Reaction ◽  
High Radioactivity

The 241Am(n,2n)240Am reaction cross section has been measured at neutron beam energy 17.5 MeV, relative to the 27Al(n,α)24Na, 197Au(n,2n)196Au and 93Nb(n,2n)92mNb reference reaction cross sections, using the activation technique. The irradiation was carried out at the Van der Graaff 5.5 MV Tandem accelerator laboratory of NCSR “Demokritos” with monoenergetic neutron beam provided by means of the 3H(d,n)4He reaction, implementing a new Ti-tritiated target. The high purity Am target has been constructed at IRMM, Geel, Belgium and consisted of 40 mg 241Am in the form of AmO2 pressed into pellet with Al2O3 and encapsulated into Al container. Due to this high radioactivity (5 GBq), the Am target was enclosed in a Pb container for safety reasons. After the end of the irradiation, the activity induced by the neutron beam at the target and reference foils, was measured off-line by two 100%, a 50% and a 16% relative efficiency, HPGe detectors.

SU-FF-T-436: Comparison of Neutron Doses to a Water Target Exposed to a 10 MeV Neutron Beam: Foil Activation Method Vs. Monte Carlo Simulations

2009 ◽  
Vol 36 (6Part15) ◽  
pp. 2622-2623
Author(s):  
R Gunasingha ◽  
C Howell ◽  
A Crowell ◽  
B Fallin ◽  
T Yoshizumi ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Neutron Beam ◽  
Activation Method ◽  
Foil Activation ◽  
Beam Foil

scholarly journals Investigation of (n,2n) reactions using the high energy neutron facility at NCSR “Demokritos”

2019 ◽  
Vol 24 ◽  
pp. 117
Author(s):  
R. Vlastou ◽  
A. Kalamara ◽  
M. Kokkoris ◽  
M. Serris ◽  
N. Patronis ◽  
...  
Keyword(s):  
Neutron Beam ◽  
Reaction Cross Section ◽  
High Energy ◽  
Reaction Cross ◽  
Activation Technique ◽  
Flux Variation ◽  
High Energy Neutron ◽  
Foil Activation ◽  
Energy Neutron ◽  
Neutron Facility

In the high energy neutron facility at the 5.5MV tandem T11/25 Accelerator of NCSR "Demokritos", the neutron beam is produced by means of the 3H(d,n)4He reaction in the energy range ~15-21 MeV and at a flux of the order of 105 -106 n/cm2s. The beam has been characterized by means of the NeuSDesc and MCNP5 Monte Carlo simulations along with the multiple foil activation technique at various neutron energies. The neutron flux has been deduced using reference reactions, such as the 27Al(n,α) reaction, while the flux variation of the neutron beam was monitored by using a BF3 detector. After the characterization, the neutron beam has been used for (n,2n) reaction cross section measurements on Hf, Au and Ir isotopes via the activation technique. The irradiations were carried out at 15.3 and 17.1 MeV.

scholarly journals Neutron Beam Characterization at Neutron Radiography (NRAD) Reactor East Beam Following Reactor Modifications

2021 ◽  
Vol 5 (2) ◽  
pp. 8
Author(s):  
Sam H. Giegel ◽  
Aaron E. Craft ◽  
Glen C. Papaioannou ◽  
Andrew T. Smolinski ◽  
Chad L. Pope
Keyword(s):  
Energy Spectrum ◽  
Neutron Flux ◽  
Neutron Beam ◽  
Neutron Energy ◽  
Neutron Radiography ◽  
Neutron Energy Spectrum ◽  
Neutron Beams ◽  
Cadmium Ratio ◽  
Foil Activation

The Neutron Radiography Reactor at Idaho National Laboratory (INL) has two beamlines extending radially outward from the east and north faces of the reactor core. The control rod withdrawal procedure has recently been altered, potentially changing power distribution of the reactor and thus the properties of the neutron beams, calling for characterization of the neutron beams. The characterization of the East Radiography Station involved experiments used to measure the following characteristics: Neutron flux, neutron beam uniformity, cadmium ratio, image quality, and the neutron energy spectrum. The ERS is a Category-I neutron radiography facility signifying it has the highest possible rank a radiography station can achieve. The thermal equivalent neutron flux was measured using gold foil activation and determined to be 9.61 × 106 ± 2.47 × 105 n/cm2-s with a relatively uniform profile across the image plane. The cadmium ratio measurement was performed using bare and cadmium-covered gold foils and measured to be 2.05 ± 2.9%, indicating large epithermal and fast neutron content in the beam. The neutron energy spectrum was measured using foil activation coupled with unfolding algorithms provided by the software package Unfolding with MAXED and GRAVEL (UMG). The Monte-Carlo N-Particle (MCNP6) transport code was used to assist with the unfolding process. UMG, MCNP6, and measured foil activities were used to determine a neutron energy spectrum which was implemented into the MCNP6 model of the east neutron beam to contribute to future studies.

scholarly journals Influence of parasitic neutrons to the 176Hf(n,2n)175Hf reaction cross section

2019 ◽  
Vol 18 ◽  
pp. 83
Author(s):  
R. Vlastou ◽  
M. Kokkoris ◽  
M. Serris ◽  
M. Lambrou ◽  
L. Sofokleous ◽  
...  
Keyword(s):  
Cross Sections ◽  
Reaction Cross Section ◽  
Liquid Scintillator ◽  
Reaction Cross ◽  
Energy Spectra ◽  
Recoil Energy ◽  
Activation Technique ◽  
Tandem Accelerator ◽  
Analysis Technique ◽  
Foil Activation

Cross sections for 176Hf(n,2n)175Hf reaction have been measured at the VdG Tandem accelerator of NCSR \Demokritos", in the neutron energy region from 8.80 to 11.02 MeV, using the activation technique. In order to account for the contamination of the 176Hf(n,2n)175Hf by the 174Hf(n,γ)175Hf reaction activated by the presence of parasitic neutrons, an experimental method has been developed based on the influence of the parasitic neutrons in the case of the (n,2n) and (n,γ) reactions on 197Au. The results were found to be consistent with the energy spectrum of the neutron beam which has been studied by means of the multiple foil activation analysis technique as well as by a liquid scintillator BC501A detector and subsequent deconvolution of its recoil energy spectra.

In vivo measurement of lithium in the body by a neutron activation analysis technique

1986 ◽  
Vol 13 (1) ◽  
pp. 45-49 ◽  
Author(s):  
D. Glaros ◽  
A. F. LoMonte ◽  
K. J. Ellis ◽  
S. Yasumura ◽  
R. W. Stoenner ◽  
...  
Keyword(s):  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
The Body ◽  
In Vivo Measurement ◽  
Analysis Technique
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