This work is a subsequent step to study the feasibility of fast neutron fluency measurements using two different complementary methods.
Np-237 samples and planar silicon detectors were mounted very ...close to each other on different sections of a subcritical assembly irradiated with the proton beam of 0,66 GeV (the Quinta assembly at the Joint Institute for Nuclear Research, Dubna, Russia) to provide both samples with the same neutron fluency. We have processed the experimental data of irradiated Np-237 actinide samples and silicon detectors directly placed on two sections of the QUINTA setup without a lead shield-reflector.
Applying the try and error method we have found found that the neutron energy for which the ratio of the fission cross section to the capture cross section of the actinide Np-237 from the nuclear data base is equal to the measured ratio of the fissioned and captured actinide isotopes. The retrieved distinct fission and capture cross sections for the distinct neutron energy from the nuclear data base describe the average values.
The considered above experimental and earlier obtained data have been shown that the higher is the average neutron energy the smaller is the difference of the neutron fluency measurement between the two methods. This effect has been expected since the silicon detector method efficiently measures the fast neutrons of the energy higher than about 170 keV while the actinide method covers a wider energy range.
Np-237 samples were irradiated with spallation neutrons produced at the ADS setup QUINTA. Six experiments were carried out at the JINR, in Dubna – one in carbon (C6+), three in deuteron, and two in ...proton beams. The energy in carbon was 24 GeV, in deuteron – 2, 4 and 8 GeV, respectively, and 660 MeV in the proton beam. In five cases the sample was located in a side window in a lead shield. In one case (660 MeV proton beam) two samples were located on the top of the QUINTA setup, one – on the top of section 2, and the second one – on the top of section 4. The transmutation study method was based on gamma-ray spectrometry. During the analysis of the spectra several fission products and one actinide were identified. Fission product activities yielded the number of fissions. The actinide (Np-238), a result of neutron capture by Np-237, yielded the number of captures.
The main goal of this work was to find out if and how the transmutation rate depended on the accelerator beam and sample location during the irradiation.
Determining the Fast Neutron Flux Density and Transmutation Level Measurements in the ADS by the use of a Threshold Nuclear Reaction. The aim of the project was determining the fast neutron flux ...density by using data from the Quinta experiment (E+T RAW collaboration). The experimental assembly based on natural uranium was irradiated by a 660 MeV proton beam. To gain the knowledge about the neutron flux inside the experimental assembly, nuclear threshold reactions of (
n
,
xn
) type were used. The level of isotopes production are measured by the activation method using a gamma radiation HPGe detector. This paper describes the Quinta assembly, experimental results, calibration procedure and average high energy neutron calculation based on yttrium (Y-89) isotopes production. In the future, results and conclusions from an experiment like this could be useful to design accelerator-driven subcritical systems (ADS) or other 4th generation fast reactors. The investigation has been performed at the Laboratory of High Energy Physics, JINR.
MCORD - MPD Cosmic Ray Detector a new features Bielewicz, M.; Milewicz-Zalewska, M.; Grodzicka-Kobylka, M. ...
EPJ Web of Conferences,
2019, Letnik:
204
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The main detector system at the Nuclotron-based Ion Collider fAcility (NICA) located in Dubna, Russia is the Multi-Purpose Detector (MPD). For better calibration reason, the MPD needs an additional ...trigger system for an off-beam calibration of MPD sub-detectors and for rejection (veto) of cosmic muons. The system should also be useful for practical astrophysics observations of cosmic showers. The consortium NICA-PL group defines goals and basic assumptions for the MPD Cosmic Ray Detector (MCORD). This article describes the conceptual design and simulation plans of the MCORD detector based on plastic scintillators with SiPM photodetectors and electronic digital system based on the MicroTCA crate.
We present 21 studies of cases of lung cancer in patients with situs inversus totalis (SIT) published worldwide. The first case was described in 1952. Thirteen patients were from Japan, 4 from ...Eastern Europe, including 2 Polish cases from the authors' center (Department of Thoracic Surgery, Pomeranian Medical University in Szczecin, Poland), 2 from Western Asia, 1 from the U.S. and 1 from Australia. Male patients (20/21) as well as left-sided lung cancer cases (14/21) and squamous cell carcinoma cases (8/21) dominated in the entire group. Thirteen patients underwent surgical treatment. There were 10 left-sided and 3 right-sided surgical interventions with uneventful intra- and postoperative course. Explorative thoracotomy was performed in one case only on the right side. Upper lobectomy was performed in 5 cases, pneumonectomy in 3 cases, lower bilobectomy and middle lobectomy in one case and lower lobectomy in two cases. Surgery was performed through thoracotomy in 10 cases, VATS-assisted approach in two cases and sternotomy in one case. Descriptions of the surgical anatomy confirmed mirror image of the anatomy in all cases and were consistent with the preoperative CT images. Preoperative diagnosis was discussed including the role of 3-D reconstruction of CT for improving perioperative safety in this group of patients. In conclusion, lung cancer/SIT cases despite inversed but regular anatomy can be operated on radically as cases with normal anatomy with preservation of intraoperative security level.
Objectives. We investigated the influence of pain decrease after lumbar microdiscectomy on the interferon gamma (IFN-γ) serum level in patients with lumbar disc herniations. The study challenges the ...mechanism of sciatica pain and the role of IFN-γ in radicular pain development. Material and Methods. We performed clinical and immunoenzymatic assessment in a group of 27 patients with lumbar radicular pain due to disc herniations before and 3 months after surgery. Clinical status was assessed with the use of the Numeric Rating Scale (NRS), the Pain Rating Index and Pain Intensity Index of McGill Pain Questionnaire (SF-MPQ), the Oswestry Disability Index (ODI), and Beck Depression Inventory (BDI). The plasma concentrations of IFN-γ were ascertained by an immunoenzymatic method. Results. We observe significant correlations between the results of the pain in the back region assessment NRS back scale after the surgery with the level of IFN-γ before the procedure (rs=0.528; p=0.008) and after the procedure (rs=0.455; p=0.025). These are moderate and positive correlations—the decrease in pain is correlated with the lower IFN-γ level. Additionally, there are significant correlations between the results of the PRI scale and the IFN-γ level. The PRI score before surgery correlates positively with IFN-γ after surgery (rs=0.462; p=0.023), and the PRI score after surgery correlates positively with IFN before surgery (rs=0.529; p=0.005) and after surgery (rs=0.549; p=0.003). All correlations are moderate in severity—severe pain before surgery correlates with a higher level of IFN-γ after surgery and also higher IFN-γ before surgery. There were significant differences in the IFN-γ level before (Z=−2.733; p=0.006) and after (Z=−2.391; p=0.017) surgery in the groups of patients with and without nerve compression. In the group of patients with nerve compression, the level of IFN-γ before and after surgery was lower. Conclusions. Less pain ratio after operation correlates with the level of IFN-γ. In the group of patients without significant nerve compression confirmed by MRI scans, the level of IFN-γ before and after surgery was higher than that in the group with nerve root compression.
The international collaboration Energy and Transmutation of Radioactive Waste (E&T RAW) performed intensive studies of several simple accelerator-driven system (ADS) setups consisting of lead, ...uranium and graphite which were irradiated by relativistic proton and deuteron beams in the past years at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The most recent setup called Quinta, consisting of natural uranium target-blanket and lead shielding, was irradiated by deuteron beams in the energy range between 1 and 8 GeV in three accelerator runs at JINR Nuclotron in 2011 and 2012 with yttrium samples among others inserted inside the setup to measure the neutron flux in various places. Suitable activation detectors serve as one of possible tools for monitoring of proton and deuteron beams and for measurements of neutron field distribution in ADS studies. Yttrium is one of such suitable materials for monitoring of high energy neutrons. Various threshold reactions can be observed in yttrium samples. The yields of isotopes produced in the samples were determined using the activation method. Monte Carlo simulations of the reaction rates leading to production of different isotopes were performed in the MCNPX transport code and compared with the experimental results obtained from the yttrium samples.
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