Thermal neutron induced (n,p) and (n,alpha) reactions on 37Ar

The 37Ar(n_th,alpha)34S and 37Ar(n_th,p)37Cl reactions were studied at the high flux reactor of the ILL in Grenoble. For the 37Ar(n_th,alpha_0) and 37Ar(n_th,p) reaction cross sections, values of (1070+/-80)b and (37+/-4)b, respectively, were obtained. Both values are about a factor 2 smaller than results of older measurements. The observed suppression of the 37(n_th,alpha_1) transition could be verified from theoretical considerations. Finally, evidence was found for the two-step 37Ar(n_th,gamma-alpha) process.Comment: 11 pages, 5 figures, accepted for publication in Nuclear Physics

The 41Ca(n,α)38Ar cross section up to 100 keV neutron energy

The 41Ca(n,alpha)38Ar reaction cross section has been studied with resonance neutrons at the GELINA neutron facility of the Institute for Reference Materials and Measurements in Geel (Belgium) from a few eV up to 100 keV. A Frisch-gridded ionization chamber with methane as detector gas was installed at a 30 meter long flight path. About 20 resonances have been identified. From the cross section data obtained, the Maxwellian averaged cross section (MACS) as a function of stellar temperature has been calculated by numerical integration

Thermal fission cross section measurements of 243Cm and 245Cm

A new measurement program was set up at SCK-CEN to determine the thermal neutroninduced fission cross section of a number of Cm isotopes. The experiments are performed at a thermal neutron beam from the graphite moderated reactor BR1 at SCK-CEN. This paper presents preliminary results of our ^243Cm(n,f) and ^245Cm(n,f) cross-section measurements

245Cm fission cross section measurement in the thermal energy region

A new cross section measurement for the ^245Cm(n,f) reaction in the thermal energy region has been performed at the GELINA neutron facility of the Institute for Reference Materials and Measurements (IRMM) in Geel, Belgium. The energy of the neutrons is determined applying the time of flight method using a flight path length of about 9 m. In the present work, the incident neutron energy covers 10 meV up to a few eV. A 98.48% enriched ^245Cm sample was mounted back-to-back with a ^10B sample in the centre of a vacuum chamber together with two surface barrier detectors positioned outside the neutron beam. One detector measured the ^10B(n,a)^7Li reaction products for the neutron flux determination, while the second one registered the ^245Cm(n,f) fragments. In this way, the neutron flux can be determined simultaneously with the fission fragments. A control measurement has been performed replacing the ^245Cm sample with a ^235U sample in order to check that the well-known ^235U(n,f) cross section can be reproduced. Our measurement yielded a ^245Cm(nth,f) cross section of 2131±43±173 b and a Westcott factor gf=0.939±0.019

Neutron induced reactions on radioactive beryllium and argon isotopes

The preparation of radioactive $^{10}$Be, $^{37}\!$Ar and $^{39}\!$Ar samples is discussed. Investigation of the $^{10}$Be(n$_{th} , \gamma$)$^{11}\!$Be , $^{37}$Ar(n$_{th} , \alpha$)$^{34}$S , $^{37}$Ar(n$_{th}$ , p)$^{37}\!$Cl and $^{39}\!$Ar(n$_{th} , \alpha$)$^{36}$S reactions is reported, and resonances in the $^{37}$Ar(n , $\alpha$)$^{34}$S reaction have been observed and analysed

Argument-Checking:A Critical Pedagogy Approach to Digital Literacy

The digital revolution brought about unprecedented changes in people’s daily lives as well as in techno-scientific contexts. In this paper, we address the problem of information overload people experience in online media, news outlets, and social media. The problem is well-known for its negative influence on the quality of online information, with abundant discussion on the promise of fact-checking and the potential role of censorship and moderation by social media. We instead discuss the issue from the perspective of digital literacy; specifically, we advance the view that our procedure of argument-checking can enhance such literacy, as a form of critical pedagogy, thereby contributing to improving the quality of online information

True ternary fission of superheavy nuclei

We found that a true ternary fission with formation of a heavy third fragment (a new type of radioactivity) is quite possible for superheavy nuclei due to the strong shell effects leading to a three-body clusterization with the two doubly magic tin-like cores. The simplest way to discover this phenomenon in the decay of excited superheavy nuclei is a detection of two tin-like clusters with appropriate kinematics in low-energy collisions of medium mass nuclei with actinide targets. The three-body quasi-fission process could be even more pronounced for giant nuclear systems formed in collisions of heavy actinide nuclei. In this case a three-body clusterization might be proved experimentally by detection of two coincident lead-like fragments in low-energy U+U collisions.Comment: 4 pages, 7 figure

Energy distributions and yields of 3H, 4He and 6He-particles emitted in the 245Cm(n_th,f) reaction

The energy distributions and yields of light charged particles emitted during thermal neutron induced fission of 245Cm have been measured at the high flux reactor of the Institute Laue Langevin in Grenoble (France). The detection of the ternary particles was done using a Delta-E/E telescope, permitting a good separation of the ternary particles. In this way, the characteristics of the energy distribution (average energy and full width at half maximum) for 4He, 3H and 6He particles as well as their emission probabilities could be determined. For the emission probabilities per fission, the following values were obtained: LRA/B=(2.15+-0.05)E-3, 3H/B=(1.85+-0.10)E-4 and 6He/B=(4.95+-1.25)E-5