scholarly journals Study of the (n,2n) reaction cross section on 174,176Hf isotopes

2020 ◽  
Vol 15 ◽  
pp. 188
Author(s):  
M. Serris ◽  
Et Al.

Cross section measurements of the 174Hf(n,2n)173Hf and 176Hf(n,2n)175Hf reactions have been performed at the VdG Tandem accelerator of NCSR “Demokritos” in Athens, in the neutron energy region from 8.8 to 11.5 MeV, using the activation technique. Statistical model calculations based on the Hauser - Feshbach theory have also been implemented by using the code EMPIRE-II with different sets of input parameters. The predictions were compared to the data of the present work as well as data from literature.

2017 ◽  
Vol 96 (4) ◽  
Author(s):  
N. Özkan ◽  
R. T. Güray ◽  
C. Yalçın ◽  
W. P. Tan ◽  
A. Aprahamian ◽  
...  

2019 ◽  
Vol 21 ◽  
pp. 123 ◽  
Author(s):  
R. Vlastou ◽  
M. Anastasiou ◽  
A. Kalamara ◽  
M. Diakaki ◽  
M. Kokkoris ◽  
...  

In the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR “Demokritos” monoenergetic neutron beams have been produced in the energy range ∼16–19 MeV using a new Ti-tritiated target of 373 GBq activity, by means of the 3H(d,n)4He reaction. The corresponding beam energies obtained from the accel- erator, were 0.8–3.7 deuterons. The maximum flux has been determined to be of the order of 106 n/s·cm2, implementing reference reactions. An investigation of the energy dependence of the neutron fluence has been carried out with the multiple foil activation technique. The beam has been used for the measurement of (n,2n) reaction cross section on several isotopes at 16.7 and 17 MeV.


2019 ◽  
Vol 21 ◽  
pp. 160
Author(s):  
A. Kalamara ◽  
R. Vlastou ◽  
M. Diakaki ◽  
M. Kokkoris ◽  
M. Anastasiou ◽  
...  

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.


2020 ◽  
Vol 239 ◽  
pp. 01001
Author(s):  
Guohui Zhang ◽  
Huaiyong Bai ◽  
Haoyu Jiang ◽  
Zengqi Cui ◽  
Yi Lu ◽  
...  

In the past two decades cooperating with Frank Laboratory of Neutron Physics (FLNP), Joint Institute for Nuclear Research (JINR) measurements of (n, α) reaction cross sections for 6Li, 10B, 25Mg, 39K, 40Ca, 54,56,57 Fe, 58Ni, 63Cu, 64,67 Zn, 95Mo, 143Nd and 147,149 Sm nuclei were performed in the MeV neutron energy region based on the 4.5 MV Van de Graaff accelerator at Peking University. In recent years, our measurements were extended in three aspects. Firstly, measurements were expanded from two-body reactions to three-body reactions such as 10B (n, t2 α). Secondly, the neutron energy region was extended from below 8 MeV to 8 - 11 MeV by using the HI-13 tandem accelerator of China Institute of Atomic Energy (CIAE), with which cross sections of 54,56 Fe(n, α)53,51Cr reactions were measured. Thirdly, based on the newly-built China Spallation Neutron Source (CSNS) Back-n WNS (White Neutron Source), differential and angle-integrated cross sections for 6Li(n, t) and 10B(n, α) reactions were measured in the neutron energy region from 1 eV to 3 MeV.


2020 ◽  
Vol 15 ◽  
pp. 104
Author(s):  
S. Galanopoulos ◽  
R. Vlastou ◽  
P. Demetriou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
...  

Systematic experimental and theoretical investigations of the 72,73Ge(n,p)72,73 Ga and 72,74Ge(n,α)69,71Znm reaction cross sections are presented in the energy range from thresh- old to about 17 MeV neutron energy. The above reaction cross sections were measured from 8.8 to 11.4 MeV by using the activation method, relative to the 27Al(n,α)24Na refer- ence reaction. The quasi-monoenergetic neutron beams were produced via the 2H(d,n)3He reaction at the 5 MV VdG Tandem T11/25 accelerator of NCSR “Demokritos”. Statisti- cal model calculations using the code EMPIRE-II (version 2.19) taking into consideration pre-equilibrium emission were performed on the data measured in this work as well as on data reported in literature.


2019 ◽  
Vol 18 ◽  
pp. 101
Author(s):  
M. Diakaki ◽  
R. Vlastou ◽  
M. Kokkoris ◽  
C. T. Papadopoulos ◽  
A. Tsinganis ◽  
...  

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.


2019 ◽  
Vol 23 ◽  
pp. 47
Author(s):  
A. Kalamara ◽  
M. Serris ◽  
A. Spiliotis ◽  
D. Sigalos ◽  
N. Patronis ◽  
...  

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.


2020 ◽  
Vol 239 ◽  
pp. 01028
Author(s):  
R. Vlastou ◽  
A. Kalamara ◽  
G. Gkatis ◽  
A. Stamatopoulos ◽  
M. Kokkoris ◽  
...  

Cross sections for the 70,76Ge(n,2n), 72,73Ge(n,p) and 72,74Ge(n, α) reactions have been measured at the 5.5 MV tandem T11/25 Accelerator Laboratory of NCSR Demokritos, using the activation technique. Neutron beams have been produced in the ~16-20 MeV energy region, by means of the 3H(d,n)4He reaction. The maximum flux has been determined to be of the order of 105 n/cm2 s, while the flux variation of the neutron beam was monitored by using a BF3 detector. The cross section has been deduced with respect to the 27Al(n, α)24Na and 93Nb(n,2n)92mNb reference reactions. The contaminations from reactions induced on neighboring Ge isotopes and leading to the same residual nucleus, have been taken into account. After the end of the irradiations, the activity induced by the neutron beams at the targets and reference foils, has been measured by HPGe detectors. Statistical model calculations using the EMPIRE code were performed on the data measured in this work as well as on data reported in literature.


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