Production cross-sections and momentum distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV

We have measured production cross sections and longitudinal momentum distributions of fragments from neutron-deficient 36Ar at 1.05 A.GeV. The production cross-sections show excellent agreement with the predictions of the semiempirical formula EPAX. We have compared these results, involving extremly neutron deficient nuclei, with model calculations to extract informa tion about the response of these models close to the driplines. The longitudinal momentum distributions have also been extracted and are compared with the Goldhaber and Morrissey systematics.Comment: 16 pages, 6 figure

Investigation of the Impact of Magnetic Fields on Scattering Muography Images

Muography is a non-invasive imaging technique that exploits cosmic-ray muons to probe various targets by analyzing the absorption or scattering of muons. The method is particularly useful for applications ranging from geophysical exploration to security screening, including the identification of nuclear materials. This study leverages both Monte Carlo simulations and the Point of Closest Approach (PoCA) algorithm for image reconstruction to specifically explore the distortions caused by magnetic fields in scattering muography images. In the PoCA algorithm, it is assumed that all scattering of a muon during its travel in material occurs at a single point, known as the PoCA point. Each PoCA point is characterized by a scattering angle, whose distribution provides insights into the density and elemental composition of the target material. However, magnetic fields can influence muon trajectories according to Lorentz law, affecting the estimated positions of the PoCA points and the calculated scattering angles. This introduces challenges in applications such as border security control systems. Moreover, the presence of magnetic fields can lead to what we term "magnetic jamming", where the resulting muography image is distorted or misleading. This effect further complicates the accurate identification and interpretation of target materials. Our findings underline the necessity to account for magnetic field distortions when utilizing scattering muography in practical scenarios

Towards portable muography with small-area, gas-tight glass Resistive Plate Chambers

Imaging techniques that use atmospheric muons, collectively named under the neologism "muography", have seen a tremendous growth in recent times, mainly due to their diverse range of applications. The most well-known ones include but are not limited to: volcanology, archaeology, civil engineering, nuclear reactor monitoring, nuclear waste characterization, underground mapping, etc. These methods are based on the attenuation or deviation of muons to image large and/or dense objects where conventional techniques cannot work or their use becomes challenging. In this context, we have constructed a muography telescope based on "mini glass-RPC planes" following a design similar to the glass-RPC detectors developed by the CALICE Collaboration and used by the TOMUVOL experiment in the context of volcano radiography, but with smaller active area (16 $\times$ 16 cm$^{2}$). The compact size makes it an attractive choice with respect to other detectors previously employed for imaging on similar scales. An important innovation in this design is that the detectors are sealed. This makes the detector more portable and solves the usual safety and logistic issues for gas detectors operated underground and/or inside small rooms. This paper provides an overview on our guiding principles, the detector development and our operational experiences. Drawing on the lessons learnt from the first prototype, we also discuss our future direction for an improved second prototype, focusing primarily on a recently adopted serigraphy technique for the resistive coating of the glass plates.Comment: 8 pages, 7 figures, XV Workshop on Resistive Plate Chambers and Related Detectors (RPC2020

Proton vs. neutron halo breakup

In this paper we show how effective parameters such as effective binding energies can be defined for a proton in the combined nuclear-Coulomb potential, including also the target potential, in the case in which the proton is bound in a nucleus which is partner of a nuclear reaction. Using such effective parameters the proton behaves similarly to a neutron. In this way some unexpected results obtained from dynamical calculations for reactions initiated by very weakly bound proton halo nuclei can be interpreted. Namely the fact that stripping dominates the nuclear breakup cross section which in turn dominates over the Coulomb breakup even when the target is heavy at medium to high incident energies. Our interpretation helps also clarifying why the existence and characteristics of a proton halo extracted from different types of data have sometimes appeared contradictory.Comment: 7 Latex pages, 3 table, 3 ps figures, to appear in Phys. Rev.

Improved stability of a compact vacuum-free laser-plasma X-ray source

We report the development of a stable high-average power X-ray source generated by the interaction of ultrashort laser pulses (35 fs, 1 mJ, 1 kHz) with a solid target in air. The achieved source stability, which is essential for the applications foreseen for these laser-driven plasma accelerators, is due to the combination of precise positioning of the target on focus and the development of a fast rotating target system able to ensure the refreshment of the material at every shot while minimizing positioning errors with respect to the focal spot. This vacuum-free laser-plasma X-ray source provides an average dose rate of 1.5 Sv/h at 30 cm and a repeatability better than 93% during more than 36 min of continuous operation per targetThis work was supported by the Spanish Ministerio de Ciencia, Innovación y Universidades under RTI2018-101578-B-C21 and FPI predoctoral BES-2017-08917 grants, Unidad de Excelencia Maria de Maeztu under project MdM-2016-0692-17-2 and the Xunta de Galicia research grant GRC ED431C 2017/54. C.R. acknowledges the MINECO project FIS2016-75652-PS

Analytical approach to electromagnetic processes in loosely bound nuclei: application to 8B

In this paper we develop an analytical model in order to study electromagnetic processes involving loosely bound neutron--rich and proton--rich nuclei. We construct a model wave function, to describe loosely bound few--body systems, having the correct behaviour both at large and small distances. The continuum states are approximated by regular Coulomb functions. As a test case we consider the two--body Coulomb dissociation of 8B and, the inverse, radiative capture reaction. The difference between using a pure two--body model and the results obtained when incorporating many--body effects, is investigated. We conclude that the interpretation of experimental data is highly model dependent and stress the importance of measuring few--body channels.Comment: Accepted for publication in Physics Letters B. Added a comparison with a potential model calculation in Fig.

Pinus halepensis afforestations and ecosystem restoration under semiarid conditions

En la segunda mitad del siglo XX se llevaron a cabo extensas repoblaciones en el SE de la Península Ibérica utilizando casi exclusivamente el pino carrasco (Pinus halepensis). El objetivo de las mismas era recuperar una cierta cubierta arbórea, desaparecida como consecuencia de diferentes usos y perturbaciones. Pese a su magnitud y a la sensibilidad de estas zonas a la desertificación, hasta la fecha no disponemos de una revisión exhaustiva de las consecuencias de estas repoblaciones y una evaluación objetiva del éxito conseguido en la restauración de estos ecosistemas. Esta revisión sería muy útil para poder desarrollar una gestión adaptativa de estos ecosistemas, y con ello optimizar los recursos asignados a su restauración. En este trabajo hemos recopilado información propia y bibliográfica sobre estas cuestiones, tratando de extraer conclusiones y de identificar cuestiones aún no solucionadas.Aleppo pine (Pinus halepensis) has been extensively used for the afforestation in SE Spain during the second half of the XXth century. The main objectives of these plantations were to increase plant protective cover and to regulate hydrological cycles. Despite the magnitude of these interventions and the sensitivity of this area to desertification, the ecological consequences of these plantations and the degree of success in restoring ecosystem integrity has not been fully evaluated. An integrated study could be very helpful to develop an adaptive management of these areas, and to optimise resources allocation. Here we review available information on the effect of P. halepensis afforestations under semiarid conditions, and identify the main lacks of knowledge.Esta revisión ha sido posible gracias a la financiación recibida a través del proyecto FANCB (Ministerio de Ciencia y Tecnología y FEDER; REN2001-0424-C02-02 / GLO)

Charge density distributions and related form factors in neutron-rich light exotic nuclei

Charge form factors corresponding to proton density distributions in exotic nuclei, such as $^{6,8}$He, $^{11}$Li, $^{17,19}$B and $^{14}$Be are calculated and compared. The results can be used as tests of various theoretical models for the exotic nuclei structure in possible future experiments using a colliding electron-exotic nucleus storage ring. The result of such a comparison would show the effect of the neutron halo or skin on the proton distributions in exotic nuclei.Comment: 11 pages, 4 figures, to be published in International Journal of Modern Physics