INTEGRAL observations of Sco X-1: evidence for Comptonization up to 200 keV

We have analyzed a long-term database for Sco X-1 obtained with the telescope IBIS onboard the INTEGRAL satellite in order to study the hard X-ray behavior of Sco X-1 from 20 up to 200 keV. Besides the data used for producing of the INTEGRAL catalog of sources, this is the longest (412 ks) database of IBIS on Sco X-1 up to date. The production of hard X-ray tails in low-mass X-ray binaries is still a matter of debate. Since most of the fits to the high-energy part of the spectra are done with powerlaw models, the physical mechanism for the hard X-ray tail production is unclear. The purpose of this study is to better constrain those possible mechanisms. Our main result shows a strong correlation between the fluxes in the thermal and nonthermal part of Sco X-1 spectra. We thus suggest that Comptonization of lower energy photons is the mechanism for producing hard X-ray tails in Sco X-1.Comment: 4 pages, 3 figures, 2 tables; officially accepted for publication (as a Letter) by A&A in 2013 January 2

Building valoristaion strategies for biodiverse products - the approach

The market valorisation of ‘diverse food products’ is crucial to increase diversity in farming systems. It involves multiple actors, from the field to the table, and requires an integrated approach to take into account several dimensions involved

Building Valorisation Strategies for Biodiverse Products - Case Studies

The market valorisation of ‘diverse food products’ is crucial to promote agrobiodiversity. Despite the differences due to the specific contexts, valorisation strategies show relevant common features

An Isochronicity-Tunable Achromat Module

This note provides closed form expressions (in the thin lens approximation) for the quadrupole strengths required to tune the R56 parameter of the isochronous module based on three identical dipoles [2] and lists the eight sets of possible ranges for the three lengths of the drift spaces separating the magnetic components. Thus it permits the design of an insertion satisfying precise geometric constraints as in the future CLIC test facility CTF3 and which is able to compress or stretch longitudinally the beam according to the settings of the quadrupoles. An application to a CTF3 transfer line is also shown

Effect of matrix parameters on mesoporous matrix based quantum computation

We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. We study the feasibility of performing quantum computation with different mesoporous matrices. We analyse which matrix materials ensure that each individual stack of quantum dots can be considered isolated from the rest of the ensemble-a key requirement of our scheme. This requirement is satisfied for all matrix materials for feasible structure parameters and GaN/AlN based quantum dots. We also show that one dimensional ensembles substantially improve performances, even of CdSe/CdS based quantum dots

Feasibility of approximating spatial and local entanglement in long-range interacting systems using the extended Hubbard model

We investigate the extended Hubbard model as an approximation to the local and spatial entanglement of a one-dimensional chain of nanostructures where the particles interact via a long range interaction represented by a `soft' Coulomb potential. In the process we design a protocol to calculate the particle-particle spatial entanglement for the Hubbard model and show that, in striking contrast with the loss of spatial degrees of freedom, the predictions are reasonably accurate. We also compare results for the local entanglement with previous results found using a contact interaction (PRA, 81 (2010) 052321) and show that while the extended Hubbard model recovers a better agreement with the entanglement of a long-range interacting system, there remain realistic parameter regions where it fails to predict the quantitative and qualitative behaviour of the entanglement in the nanostructure system.Comment: 6 pages, 5 figures and 1 table; added results with correlated hopping term; accepted by EP

Confirming the thermal Comptonization model for black hole X-ray emission in the low-hard state

Hard X-ray spectra of black hole binaries in the low/hard state are well modeled by thermal Comptonization of soft seed photons by a corona-type region with $kT$\thinspace$\sim 50${\thinspace}keV and optical depth around 1. Previous spectral studies of 1E{\thinspace}1740.7$-$2942, including both the soft and the hard X-ray bands, were always limited by gaps in the spectra or by a combination of observations with imaging and non-imaging instruments. In this study, we have used three rare nearly-simultaneous observations of 1E{\thinspace}1740.7$-$1942 by both XMM-Newton and INTEGRAL satellites to combine spectra from four different imaging instruments with no data gaps, and we successfully applied the Comptonization scenario to explain the broadband X-ray spectra of this source in the low/hard state. For two of the three observations, our analysis also shows that, models including Compton reflection can adequately fit the data, in agreement with previous reports. We show that the observations can also be modeled by a more detailed Comptonization scheme. Furthermore, we find the presence of an iron K-edge absorption feature in one occasion, which confirms what had been previously observed by Suzaku. Our broadband analysis of this limited sample shows a rich spectral variability in 1E{\thinspace}1740.7$-$2942 at the low/hard state, and we address the possible causes of these variations. More simultaneous soft/hard X-ray observations of this system and other black-hole binaries would be very helpful in constraining the Comptonization scenario and shedding more light on the physics of these systems.Comment: 6 pages, two figures, accepted for publication in A&

Preliminary design of the CLIC drive-beam transfer line

In the drive-beam generation complex of CLIC there is an important beam transfer line between the drive-beam accelerator and the drive- beam decelerators, where the 30 GHz RF power is generated in the decelerator structures In the drive-beam generation complex of CLIC there is an important beam transfer line between the drive-beam accelerator and the drive-beam decelerators, where the 30 GHz RF power is generated in the decelerator structures. The design proposed for this transport system is based on building blocks or beam optics subsystems, which have been individually studied in detail and can be combined in order to cover specific functions. One function consists of bending the beams wherever required by the geometrical layout, so as to preserve the bunch length and keep the bending arc compact and compatible with acceptable synchrotron radiation. Other functions are to adjust the path length of each drive beam for synchronism with the main-linac beam and to compress or stretch the bunch according to the needs. Furthermore, there are vertical and horizontal beam translations, isochronous or acting as a compressor, and b-function transformers for matching the optics. All these functions are necessary in the drive-beam transfer that precedes injection into the decelerators

Experimental insertions made of two symmetric triplets

The reported study is based on the analytical treatment developed for an experimental collider insertion made of two symmetric triplets,the inner triplet located near the interaction point (IP) and th e outer triplet preceding a regular lattice. These two triplets are assumed to be symmetric in their geometry and quadrupole strengths, but not in their Twiss parameters. The method is applied to an i nsertion of the type of an experimental LHC insertion. The drift between the IP and the first quadrupole is fixed and the inner triplet is constrained to achieve a beta-crossing with equal and opposit e slopes (alpha-values) in the two planes. The outer triplet acts then as a FODO transformer from beta-crossing to beta-crossing in order to match the lattice. The analysis provides in a given paramet er interval all the existing solutions for the distance between triplets and the total insertion length, as functions of one gradient and the quadrupole separation in the inner triplet. The variation of the quadrupole strengths when the beta-functions increase at the IP (detuning) is studied and the extension from thin lens to thick lens illustrated