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The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20GeV/
c
protons impinging on a lead target. The facility, aiming primarily at the ...measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
As
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Al has important applications in reactor science and technology, perfect understanding of its various cross sections in the wide range of energy is indispensable. Scarcity of experimental data ...particularly in high energy makes theoretical evaluation essential. In the present work, different neutron interaction cross sections of
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Al in the energy range 0.1–200 MeV have been evaluated by TALYS 1.9. The reaction grid, outgoing light particle production and probable production routes are also analyzed. The present evaluations are compared with the available experimental and evaluated nuclear data: ENDF/B-VIII, JENDL-4.0, etc. This is generally in good agreement except 0.7–6 MeV of projectile energies. In this energy range, diffuseness and geometrical parameters are adjusted to overcome the disagreement. In the lower-energy region, mainly elastic scattering is observed. Shape of non-elastic curve is well produced; however, there is small energy shift between evaluated and experimental data.
Neutron-induced fission cross-sections of minor actinides have been measured using the n_TOF white neutron source at CERN, Geneva, as part of a large experimental program aiming at collecting new ...data relevant for nuclear astrophysics and for the design of advanced reactor systems. The measurements at n_TOF take advantage of the innovative features of the n_TOF facility, namely the wide energy range, high instantaneous neutron flux and good energy resolution. Final results on the fission cross-section of 233U, 245Cm and 243Am from thermal to 20 MeV are here reported, together with preliminary results for 241Am. The measurement have been performed with a dedicated Fast Ionization Chamber (FIC), a fission fragment detector with a very high efficiency, relative to the very well known cross-section of 235U, measured simultaneously with the same detector.
The Pohang Neutron Facility based on an electron linac was operated for total neutron crosssection
measurements by using the pulsed neutrons produced in a water-cooled Ta-target with
a water ...moderator. We investigated the photo-neutrons produced in the water-cooled Ta-target
system by using the Monte-Carlo simulation code MCNPX, version 2.5e, and the results were
checked with the experimental values. The optimum conditions of the target system and the
experimental setup to maximize the thermal neutron production were investigated. KCI Citation Count: 16
At the n_TOF experiment at CERN a dedicated single-crystal chemical vapor deposition (sCVD) Diamond Mosaic-Detector has been developed for (n,α) cross-section measurements. The detector, ...characterized by an excellent time and energy resolution, consists of an array of 9 sCVD diamond diodes. The detector has been characterized and a cross-section measurement has been performed for the 59Ni(n,α)56Fe reaction in 2012. The characteristics of the detector, its performance and the promising preliminary results of the experiment are presented.
•A large-area detector of 3 ×3 sCVD diamonds was built for (n, α) measurements.•The 59Ni(n, α)56Fe cross-section was measured successfully at n_TOF/CERN.•The energy resolution of the detector meets the expectations from simulations.•The reaction products during the measurement at n_TOF could clearly be separated.•The detector is suitable for (n, α) measurements in a heterogeneous beam.
This study concerns an assessment of essential and toxic metals (Zn, Cu, As, Cr and Cd) in some popular farm fishes which are largely consumed by the populations of the Southern region in Bangladesh. ...Three different species of fish (T. nilotica, P. pangasius and L. rohita) were collected from four representative farms located in the Fatickchari, Hathazari, Patiya and Raozan Upazila of Chittagong district. Flame Atomic Absorption Spectrometer (FAAS) and Graphite Furnace Atomic Absorption Spectrometer (GFAAS) were used to measure the metal concentrations. The order of concentration of metals in flesh was Zn > Cu > Cr > As > Cd with values of 16.205 ± 0.303 > 0.874 ± 0.037 > 0.590 ± 0.05 >0.042 ± 0.003 > 0.004 ± 0.00 (mg/kg dw) in T. nilotica, 20.324 ± 0.697 > 1.035 ± 0.050> 0.577 ± 0.074> 0.045 ± 0.005 > 0.006 ± 0.000 (mg/kg dw) in P. pangasius and 22.270 ± 0.745 > 0.953 ± 0.525 > 0.623 ± 0.060 > 0.035 ± 0.002 > 0.004 ± 0.000 (mg/kg dw) in L. rohita. Measured data lie within the permissible limits recommended by WHO/FAO. Potential metal toxicity to human health following the consumption of the studied fishes was estimated via a number of hazard parameters: Daily intake of metal (DIM), Target hazard quotient (THQ), Hazard index (HI) and Target risk (TR), all of the data show values within the recommended level given by regulatory bodies. Estimated TR for potential carcinogenic metals As, Cr and Cd were found in the range (10−6 - 10−5), which lies within the US-EPA risk range of 10−6 - 10−4. Note that, fish consumption forms a minor part of the total diet while the US-EPA risk range is for the dietary intake from all foods. Therefore the estimated risk may not be totally neglected. Moreover, considering the non-biodegradability of toxic metals and their potential uptake in fish tissues, reduction in metal supplementation in fish feed should be introduced and periodic monitoring of fish may help to mitigate non-essential metal toxicity to consumers.
•Toxic heavy metals in fishes from Southern region of Bangladesh were determined for the first time.•Concentrations of non-essential As, Cd and Cr show low level in the studied farmed fishes.•THQ, TR and HI were all below the permissible level, discard any serious health risk to the consumer.•Zn, Cu, As, Cr and Cd may originated from anthropogenic sources or metal supplementation in fish feed.
For an external radiotherapy procedure, the tissue phantom ratio (TPR20,10) is used as a quality index. This work presents an estimate of TPR20,10 using two cylindrical ionization chambers (NE2571 ...Farmer and PTW30013) in three high-energy photon modes (6, 10 and 15 MV) using both the Monte Carlo (MCNP) process and the experimental setup. The MCNP (version MCNP5) was used for the simulation of photon beams delivered by Varian-2300CD for the determination of TPR20,10 according to technical report series (TRS) 398. Again applying the same protocol TPR20,10 values were measured experimentally with NE2571 Farmer and PTW30013 chambers for the same medical linear accelerator (LINAC). The differences of TPR20, 10 between MCNP and experimental values were found for NE2571 Farmer chamber within 4.17 percent, 2.9 percent and 2.5 percent and similarly, these were within 3.89 percent, 2.71 percent and 1.98 percent at 6, 10 and 15 MV respectively for PTW30013. The TPR20,10 values simulated by our calculated MCNP demonstrated strong agreement with our experimental results.
The neutron total cross-sections and resonance parameters of Niobium (Nb) and Palladium (Pd) were measured in the neutron energy regions from 0.1 eV to 100 eV by using the time-of-flight method at ...the Pohang Neutron Facility, Korea, which consists of an electron linear accelerator, a water-cooled Tantalum (Ta) target with a water moderator, and a 12.06 m long time-of-flight path. A
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Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm was used as a neutron detector, and high purity natural Nb and Pd metallic sheets with thickness of 15 mm (0.0833 atoms/barn) and 1 mm (0.0068 atoms/barn) respectively, were used for the neutron transmission measurements. The notch filters composed of Cobalt (Co), Indium (In), and Cadmium (Cd) were used to estimate the background level and also to calibrate energy. In order to reduce the gamma-ray background from Bremsstrahlung and from neutron capture, we employed a neutron-gamma separation system based on their different pulse shapes. The resonance parameters of
nat
Nb and
nat
Pd were obtained from the transmission ratio by using the SAMMY code, which utilizes both Doppler and resolution broadening effects and Bayes’ generalized least squares technique. The present measurements were compared with the existing experimental and the evaluated reactions data files.
A low profile multi-slotted patch antenna is developed for fifth generation (5G) wireless communication application. The required wide operating band is achieved by good coupling between the ...multi-slotted radiator and the ground. The partial ground not only helps to reduce antenna size but also the ground plane dependency and undesired cross-polarization field. The antenna is enabled to operate at 3.15 to 5.61 GHz band for S 11 ≤ -10 dB. The wideband antenna presented in this paper also achieved good gain and efficiency, and exhibits nearly omni-directional radiation patterns which make it very suitable for being used in portable communication applications.
We focus on the comparative study of dosimetry protocols in radiotherapy for accelerated photon and electron delivered from medical linear accelerator (LINAC). In this study, a comparison between the ...protocols (TRS 398, DIN 6800-2 and TG 51) for both the electron and photon delivered from Clinac 2300CD and Clinac DHX 3186 were performed. We used photon beams with energies of 6 and 15 MV and electron beams of 4, 6, 9, 12, 15 and 18 MeV for both Medical Linac. In case of Clinac the maximum deviations for the relative dose at Dmax for the photon beam (15 MV) among the protocols was observed to be 1.18% between TRS-398 and TG-51, 1.56% between TG-51 and DIN 6800-2; and 0.41% between TRS-398 and DIN 6800-2. Conversely, these deviations were 3.67% between TRS-398 and TG-51, 3.92% between TG-51 and DIN 6800-2 for 4 MeV and 0.95% between TRS-398 and DIN 6800-2 in the case of Clinac 2300 CD for the PTW Markus and Exradin A10. For the measurement of the maximum absorbed dose depth to water using three protocols, the maximum deviations were observed between TRS 398 and TG-51 as well as TG51 and DIN 6800-2.
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