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.

scholarly journals New measurement of the 241Am(n,2n)240Am cross section

2019 ◽  
Vol 20 ◽  
pp. 2
Author(s):  
A. Kalamara ◽  
M. Diakaki ◽  
R. Vlastou ◽  
M. Kokkoris ◽  
N. Nicolis ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
High Purity ◽  
Beam Energy ◽  
Gamma Ray ◽  
Activation Technique ◽  
Tandem Accelerator ◽  
Hpge Detectors ◽  
Reference Reaction ◽  
High Radioactivity

Cross section for 241Am(n,2n)240Am reaction has been measured at the VdG Tandem accelerator of NCSR “Demokritos", at neutron beam energy 10.4 MeV, using the activation technique. The high purity and high radioactivity (5GBq) Am target has been constructed at IRMM, Belgium and consisted of 40 mg Am in the form of AmO2 pressed into pellet with Al2O3 and encapsulated into Al container. The absolute flux of the beam was obtained with respect to the 27Al(n,α)24Na reference reaction. The induced gamma-ray activity of 240Am and 24Na was measured with high resolution HPGe detectors.

scholarly journals Cross section measurement of the 191Ir(n,2n)190Ir reaction

2019 ◽  
Vol 26 ◽  
pp. 166
Author(s):  
A. Kalamara ◽  
R. Vlastou ◽  
M. Kokkoris ◽  
N. Patronis ◽  
M. Serris ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Beam ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Model Parameters ◽  
Activation Technique ◽  
Incident Neutron ◽  
Tandem Accelerator ◽  
Hpge Detectors ◽  
The Cross

The cross section of the 191Ir(n,2n) reaction was experimentally determined relative to the 27Al(n,α)24Na reference reaction one, for incident neutron beam energies ranging from 15.3 to 20.9 MeV, by means of the activation technique. The quasi-monoenergetic neutron beams were produced at the 5.5 MV Tandem Accelerator ofNCSR "Demokritos" via the 3H(d,n)4He reaction. Following the irradiations the activity induced by the neutron beam at the targets and reference foils was measured by HPGe detectors. The cross sections for the population of the second isomeric state (m2) of 190Ir and the sum of the ground and isomeric states (g+m1+0.086 m2) were independently determined. Additionally, theoretical calculations of the above cross sections were carried out using the EMPIRE code. The details of these calculations concerning the optical model parameters, are described in the present work.

scholarly journals Activation cross section of the (n,2n) reaction on Hf isotopes

2019 ◽  
Vol 23 ◽  
pp. 47
Author(s):  
A. Kalamara ◽  
M. Serris ◽  
A. Spiliotis ◽  
D. Sigalos ◽  
N. Patronis ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Reaction Cross Section ◽  
Beam Energy ◽  
Reaction Cross ◽  
Activation Technique ◽  
Incident Neutron ◽  
Activation Cross Section ◽  
Reference Reaction

Cross sections of the 174Hf(n,2n)173Hf and 176Hf(n,2n)175Hf reactions have been experimentally determined relative to the 27Al(n,α)24Na reference reaction at incident neutron energies of 15.3 and 17.1 MeV by means of the activation technique. The irradiations were carried out at the 5 MV tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" with monoenergetic neutron beams provided via the 3H(d,n)4He reaction, using a new Ti-tritiated target of 373 GBq activity. In the determination of the 176Hf(n,2n)175Hf reaction cross section the contamination of the 174Hf(n,γ)175Hf and 177Hf(n,3n)175Hf reactions has been taken into account. Moreover, the neutron beam energy has been studied by means of Monte Carlo simulation codes and the neutron flux has been determined via the 27Al(n,α)24Na reference reaction.

scholarly journals Cross Section Measurements of (n,p) Reactions on Ge Isotopes

2020 ◽  
Vol 27 ◽  
pp. 185
Author(s):  
G. Gkatis ◽  
Rosa Vlastou ◽  
A. Kalamara ◽  
S. Chasapoglou ◽  
M. Kokkoris ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Systematic Investigation ◽  
Reaction Cross ◽  
Isotopic Effect ◽  
Activation Method ◽  
Tandem Accelerator ◽  
Reaction Cross Sections ◽  
Existing Data

The 72,73Ge(n,p)72,73Ga reaction cross sections were measured at the 5.5MV HV Tandem accelerator of  NCSR “Demokritos”, at neutron energies 17.7 and 19.3 MeV by using the activation method. The contamination from the (n,d) and (n,np)  reactions  on 73Ge and 74 Ge, leading to the 72Ge and 73Ge residual nuclei, respectively, has been  taken  into account, implementing the corresponding cross sections from  TENDL-2017. A systematic investigation of the isotopic effect on all Ge isotopes is also presented, from threshold up  to 20MeV, using the present data along with existing data in literature

scholarly journals A simple angle integration method for the determination of capture reaction cross sections

2019 ◽  
Vol 24 ◽  
pp. 129
Author(s):  
V. Michalopoulou-Petropoulou ◽  
V. Lagaki ◽  
M. Axiotis ◽  
V. Foteinou ◽  
A. Lagoyannis ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Integration Method ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Distribution Method ◽  
Hpge Detectors ◽  
Secondary Transitions ◽  
Reaction Cross Sections

In order to determine the cross section of a reaction by the angular distribution method, it is essential to calculate the angular distributions of all secondary transitions that lead to the ground state. This is achieved by analysing spectra from HPGe detectors at various detection angles, which is a time consuming process. In this work, a simpler angle integration method is presented that allows to determine cross sections of capture reactions by measuring spectra at fewer detection angles.

scholarly journals Attempted study of the 237Np(n,2n)236Np reaction cross section at 9.5 MeV

2019 ◽  
Vol 18 ◽  
pp. 101
Author(s):  
M. Diakaki ◽  
R. Vlastou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
A. Tsinganis ◽  
...  
Keyword(s):  
Cross Section ◽  
Gamma Ray ◽  
Gamma Spectroscopy ◽  
Reaction Cross ◽  
Activation Technique ◽  
Incident Neutron ◽  
Incident Neutron Energy ◽  
Tandem Accelerator ◽  
Section Measurement ◽  
High Gamma

The cross section measurement of the 237Np(n,2n)236Np reaction has been attempted at an incident neutron energy of 9.5 MeV by means of the activation technique. The neutron beam was produced via the 2H(d,n)3Ηe reaction at the VdG Tandem accelerator of NCSR “Demokritos”. It is the second time that this measurement has been tried with a gamma spectroscopy method and the difficulties faced due to the high gamma ray background produced by the sample itself and the fission fragments produced by the irradiation, in combination with the very low intensity of the gamma ray of interest are being reported.

Nonequilibrium effects in α-particle induced reactions on gallium isotopes

1989 ◽  
Vol 67 (9) ◽  
pp. 870-875 ◽  
Author(s):  
I. A. Rizvi ◽  
M. K. Bhardwaj ◽  
M. Afzal Ansari ◽  
A. K. Chaubey
Keyword(s):  
Cross Sections ◽  
Residual Nucleus ◽  
Reaction Cross ◽  
Activation Technique ◽  
Individual Reaction ◽  
Reaction Channels ◽  
Stacked Foil Activation Technique ◽  
The Individual ◽  
Reaction Cross Sections

The stacked foil activation technique and Ge(Li) γ-ray spectroscopy have been employed for the determination of the excitation functions, up to 60 MeV, of six reactions, 69Ga(α,n), (α,2n), (α,3n), (α,p3n); 71Ga(α,n) and (α,4n). Since natural gallium used as the target has two odd-mass stable isotopes of abundance, 69Ga(60.1%) and 71Ga(39.9%), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of their theoretical cross sections. A preliminary theoretical comparison with the preequilibrium geometry-dependent hybrid (GDH) model has been done using an initial exciton number no = 4 (2n + 2p + 0h), and general agreement was found for all reactions at high energies.

QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION PROBABILITY AND CROSS SECTION OF THE REACTION LiH + H

2013 ◽  
Vol 12 (01) ◽  
pp. 1250093 ◽  
Author(s):  
YULIANG WANG ◽  
JINCHUN ZHANG ◽  
BAOGUO TIAN ◽  
KUN WANG ◽  
XIAORUI LIANG ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Reaction Cross ◽  
Reaction Probability ◽  
Title Reaction ◽  
Reaction Cross Sections

Based on the new accurate potential energy surface of the ground state of LiH2 system. Quasi-classical trajectory (QCT) calculations were carried out for the reaction LiH + H . The reaction probability of the title reaction for J = 0 has been calculated. The reaction cross sections were calculated as functions of the collision energy in the range 0.1–2.5 eV. The results were found to be well consistent with the previous real wave packet (RWP) and QCT results.

scholarly journals Chemical Reaction Kinematics

1968 ◽  
Vol 23 (12) ◽  
pp. 2080-2083 ◽  
Author(s):  
D. Hyatt ◽  
K. Lacmann
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Impulse Approximation ◽  
Reaction Cross ◽  
Molecule Reaction ◽  
Polarization Theory ◽  
Reaction Cross Sections

A Bendix time of flight mass spectrometer has been modified to enable the determination of some ion-molecule reaction cross sections in the energy range 1 — 100 eV.In the reactions studiedX+ + D2 → XD++Dwhere X may be Ar, N2 or CO, the results obtained agree with the predictions of the polarization theory in the range below 10 eV despite the fact that no intermediate complex is formed at these energies. Between about 10—50 eV where spectator stripping occurs the cross section follows an approximate E-l dependence. Above these energies the results are consistent with a transition to a region in which knock-on processes predominate and where an impulse approximation treatment would be valid.

Fission spectrum averaged cross section measurements of some neutron threshold reactions of relevance to medical radionuclide production

2005 ◽  
Vol 93 (9-10) ◽  
Author(s):  
Jamshed H. Zaidi ◽  
M. Arif ◽  
I. Fatima ◽  
Shahida Waheed ◽  
Shujaat Ahmad ◽  
...  
Keyword(s):  
Nuclear Reaction ◽  
Cross Section ◽  
Cross Sections ◽  
Fission Neutron ◽  
Reaction Cross ◽  
Radionuclide Production ◽  
Fission Neutron Spectrum ◽  
Fission Spectrum ◽  
Medical Radionuclide ◽  
Reaction Cross Sections

SummaryA resume is given of radiochemical measurements of nuclear reaction cross sections relevant to the production of some medically important radionuclides carried out at PINSTECH during the last decade. Systematic studies on fission neutron spectrum averaged cross sections of several threshold reactions, like (

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