Probing for high-momentum protons in He-4 via the He-4(e, e ' p)X reactions

©2022 American Physical Society. Artículo firmado por 110 autores. Special thanks to Silviu Covrig for providing the CFD calculations as a possibility to understanding the target vertex spectra for the SRC target. Special thanks to Or Hen for valuable discussions and inputs on the paper. The research presented in this paper is partially supported by the U.S. National Science Foundation under Grants No. PHY-2012413 (F.B.), No. PHY 16-15067 (F.B.), and No. PHY 09-69380 (K.A.). This work was supported by the U.S. Department of Energy under Contract No. DE-AC05-06OR23177 under which Jefferson Science Associates operates the Thomas Jefferson National Accelerator Facility.Experimental cross sections for the He-4(e, e'p)X reactions in the missing energy range from 0.017 to 0.022 GeV and up to a missing momentum of 0.632 GeV/c at x(B) = 1.24 and Q(2) = 2 (GeV/c)(2) are reported. The data are compared to relativistic distorted-wave impulse approximation calculations for the He-4(e, e'p)H-3 channel. Significantly more events are observed for p(m) >= 0.45 GeV/c than are predicted by the theoretical model, and striking fluctuations in the ratio of data to the theoretical model around p(m) = 0.3 GeV/c are possible signals of initial-state multinucleon correlations.U.S. National Science FoundationU.S. Department of EnergyDepto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEpu

Hybrid Monte Carlo dose algorithm for low energy X-rays intraoperative radiation therapy

Low energy X-rays Intra-Operative Radiation Therapy (XIORT) treatment delivered during surgery (ex: INTRABEAM, Carl Zeiss, and Axxent, Xoft) can benefit from accurate and fast dose prediction in a patient 3D volume

Coal-Based Carbon Foams. Influence of the Precursor Coal

Abstract Carbon foams were obtained from several bituminous coals with different plasticity and volatile matter content by a two-stage thermal process. The first stage, a controlled carbonisation treatment under pressure at 450-500 °C, is responsible for the final textural properties of the foam. In the second stage the carbonisation product was baked at 1100 °C. The foams produced display a macroporous texture with plasticity, volatile matter content and maceral composition of the precursor coals having an influence on the apparent density and the pore size of the resultant porous products

Global relativistic folding optical potential and the relativistic Green's function model

Optical potentials provide critical input for calculations on a wide variety of nuclear reactions, in particular, for neutrino-nucleus reactions, which are of great interest in the light of the new neutrino oscillation experiments. We present the global relativistic folding optical potential (GRFOP) fits to elastic proton scattering data from C-12 nucleus at energies between 20 and 1040 MeV. We estimate observables, such as the differential cross section, the analyzing power, and the spin rotation parameter, in elastic proton scattering within the relativistic impulse approximation. The new GRFOP potential is employed within the relativistic Green's function model for inclusive quasielastic electron scattering and for (anti) neutrino-nucleus scattering at MiniBooNE kinematics

Search for shape-coexisting 0(+) states in Ni-66 from lifetime measurements

The lifetime of the 0(3)(+) state in Ni-66, two neutrons below the N = 40 subshell gap, has been measured. The transition B(E2; 0(3)(+) -> 2(1)(+)) is one of the most hindered E2 transitions in the Ni isotopic chain and it implies that, unlike Ni-68, there is a spherical structure at low excitation energy. We have performed extensive shell-model calculations that correctly predict this result, obtaining a spherical 0(+) state at the correct energy and with an extremely low B(E2; 0(3)(+)-> 2(1)(+)) value

Assessment of the effectiveness of reported Water Framework Directive Programmes of Measures - Part II – development of a system of Europe-wide Pressure Indicators

The EC DG JRC is using in-house models and other information to build indicators of pressures on water bodies, in the context of the 2nd river basin management plan (RBMP) implementation assessment (Water Framework Directive (WFD) 60/2000/EC, art. 18) and review of the WFD (art. 19). These indicators are meant to provide a picture of major water pressures at the European scale. The main reason to develop a set of independent pressure indicators is the need to evaluate and monitor the effectiveness of the EU water policies at broad. If the indicators are realistic, the models used for their computation can be used also as tools to simulate scenarios with changing pressures, as a result of policies or other drivers (such as climate changes, implementation of measures or EU sectorial policies). The EC DG ENV is steering the development of an integrated hydro-economic modelling platform in support to the evaluation of policies, with the broadest possible involvement of the EU Member States, and collaborates with DG JRC by leading a large study on the economics of water in Europe also in order to supplement JRC’s biophysical models and indicators with additional economic evidence about the costs and benefits of reducing pressures and improving the conditions of freshwater and marine ecosystems. Another question is whether the pressures are evaluated consistently throughout the European Union. The JRC indicators could be used to benchmark pressure and status reported by the Member States at a different scale. In fact, if JRC indicators are sufficiently reliable, it is expected that overall trends will be consistent with the pressures reported by the Member States. At the same time, JRC indicators do not take into account local conditions in specific water bodies, and should not be compared to reported pressures and status at water body level. The aim of benchmarking is to understand the reasons for assessment discrepancies, primarily for verification purposes. In particular, discrepancies should not be considered per se as evidence of non-compliance in the implementation of the WFD by Member States. particularly, if a given river basin is flagged by Member State reports to suffer from a given pressure, but this is not found in the JRC pressure indicators, the knowledge available at the Commission is likely inadequate for that river basin. The benchmarking process with reported pressures/status in itself could prompt the Commission to seek an explanation for the discrepancies, and eventually to update the indicators, with the overall goal of a coherent and shared vision of pressures at the European and river basin district scales. DG ENV encourages Member States to provide feedback to DG JRC on the indicators and the underpinning models, so that the European scale picture of water pressures they provide can be improved to a sufficient level of realism and representativeness, and can be consequently used as a basis for European water policy evaluation and development. As a first opportunity for this process, the JRC organised a workshop in Ispra on 11-12 May 2016 with the aim to collect feedback from experts on the proposed methodologies and indicators. The JRC pressure indicators are updated over time, as new knowledge is available at the European level. Therefore the benchmarking of local and European assessments is supposed to be a continuous process. The reviews by experts in the Member States should not add to the administrative burden related to the WFD, but should be conducted with the modalities of scientific peer reviews. It will be necessary to pay significant attention to the way the results are communicated, so to clarify the content of the indicators and avert risks of misinterpretation. The review of the indicators will serve also this purpose. This document summarizes the JRC indicators, the state of play with their update and further development, and the outcomes of the workshop held in Ispra on May 11-12, 2016.JRC.D.2-Water and Marine Resource

Multi-modal ultrasound imaging for breast cancer detection

This work describes preliminary results of a two-modality imaging system aimed at the early detection of breast cancer. The first technique is based on compounding conventional echographic images taken at regular angular intervals around the imaged breast. The other modality obtains tomographic images of propagation velocity using the same circular geometry. For this study, a low-cost prototype has been built. It is based on a pair of opposed 128-element, 3.2 MHz array transducers that are mechanically moved around tissue mimicking phantoms. Compounded images around 360 degrees provide improved resolution, clutter reduction, artifact suppression and reinforce the visualization of internal structures. However, refraction at the skin interface must be corrected for an accurate image compounding process. This is achieved by estimation of the interface geometry followed by computing the internal ray paths. On the other hand, sound velocity tomographic images from time of flight projections have been also obtained. Two reconstruction methods, Filtered Back Projection (FBP) and 2D Ordered Subset Expectation Maximization (2D OSEM), were used as a first attempt towards tomographic reconstruction. These methods yield useable images in short computational times that can be considered as initial estimates in subsequent more complex methods of ultrasound image reconstruction. These images may be effective to differentiate malignant and benign masses and are very promising for breast cancer screening. (C) 2015 The Authors. Published by Elsevier B.V

Nuclear astrophysics with radioactive ions at FAIR

The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes

Design of an X-ray irradiator based on a standard imaging X-ray tube with FLASH dose-rate capabilities for preclinical research

This work was funded by Comunidad de Madrid under project B2017/BMD-3888 PRONTO-CM "Protontherapy and nuclear techniques for oncology". Support by the Spanish Government (RTI 2018-098868-B-I00, RTC-2015-3772-1, XPHASE-LASER, CPP 2021-008751 NEW-MBI) , as well as European Regional and Resilience Funds, and the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 793576 (CAP-PERAM) is acknowledged. This is a contribution for the Moncloa Campus of International Excellence, "Grupo de Física Nuclear-UCM", Ref. 910059. Part of the calculations of this work were performed in the "Cluster de Calculo para Técnicas Físicas", funded in part by UCM and in part by EU Regional Funds.We propose a new concept of small animal X-ray irradiator based on a conventional imaging X-ray tube for preclinical research. In this work we assessed its feasibility to deliver FLASH dose rates. Our design puts the imaging X-ray tube into a shielded cabinet, which makes the system affordable and suitable to use without disruption in existing laboratories and with minimum regulatory burden. Two conventional 150 kVp X-ray tubes were characterized with Gafchromic films for dose rates and dose uniformity. Monte Carlo simulations were also performed to model the irradiator, and the efficiencies of the tube and dose rates (with and without additional filtration) were calculated and compared with measurements. The feasibility of achieving ultra-high dose rates was determined from the rating charts provided by the manufacturer and measurements. The small animal irradiator proposed in this work was able to deliver conventional dose rate irradiation (0.5-1 Gy/min) at 150 kVp at 20 cm distance with minimum amount of filtration. FLASH irradiations (a 10 Gy dose delivered at >40 Gy/s) were also possible at the maximum capabilities of the tubes by placing the samples at the closest possible distances from the sources. A first prototype has already been built and characterized.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEComunidad de MadridGobierno de EspañaEuropean Regional and Resilience FundsEuropean Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grantMoncloa Campus of International Excellence, "Grupo de Fisica Nuclear-UCM"Universidad Complutense de Madrid (UCM)EU Regional Fundspu

Fast optimized Monte Carlo phase-space generation and dose prediction for low energy x-ray intra-operative radiation therapy

Low energy x-ray intra-operative radiation therapy (IORT) is used mostly for breast cancer treatment with spherical applicators. X-ray IORT treatment delivered during surgery (ex: INTRABEAM (R), Carl Zeiss) can benefit from accurate and fast dose prediction in a patient 3D volume. However, full Monte Carlo (MC) simulations are time-consuming and no commercial treatment planning system (TPS) was available for this treatment delivery technique. Therefore, the aim of this work is to develop a dose computation tool based on MC phase space information, which computes fast and accurate dose distributions for spherical and needle INTRABEAM (R) applicators. First, a database of monoenergetic phase-space (PHSP) files and depth dose profiles (DDPs) in water for each applicator is generated at factory and stored for on-site use. During commissioning of a given INTRABEAM (R) unit, the proposed fast and optimized phase-space (FOPS) generation process creates a phase-space at the exit of the applicator considered, by fitting the energy spectrum of the source to a combination of the monoenergetic precomputed phase-spaces, by means of a genetic algorithm, with simple experimental data of DDPs in water provided by the user. An in-house hybrid MC (HMC) algorithm which takes into account condensed history simulations of photoelectric, Rayleigh and Compton interactions for x-rays up to 1 MeV computes the dose from the optimized phase-space file. The whole process has been validated against radiochromic films in water as well as reference MC simulations performed with pen Easy in heterogeneous phantoms. From the pre-computed monoenergetic PHSP files and DDPs, building the PHSP file optimized to a particular depth-dose curve in water only takes a few minutes in a single core ([email protected] GHz), for all the applicators considered in this work, and this needs to be done only when the x-ray source (XRS) is replaced. Once the phase-space file is ready, the HMC code is able to compute dose distributions within 10 min. For all the applicators, more than 95% of voxels from dose distributions computed with the FOPS+hybrid code agreed within 7%-0.5 mm with both reference MC simulations and measurements. The method proposed has been fully validated and it is now implemented into radiance (GMV SA, Spain), the first commercial IORT TPS