[en] The TJ-II ECRH heating system consists of two gyrotrons, which can deliver a maximum power of 300 kW at a frequency of 53.2 GHz. Another 28 GHz gyrotron is going to be used in the Bernstein waves heating system. In order to get the required frequency, the gyrotrons need and homogeneous magnetic field of several tesla, which is generated by a superconducting coil field by a current source. This document describes the current source control as well as the high precision ammeters control. These ammeters measure the current in the superconducting coils. The user interface and the programming of the control system are described. The communication between devices is also explained. (author) 9 Refs

[en] The difficulty that exists in the analysis of mechanical stresses in bones is high due to its complex mechanical and morphological characteristics. This complexity makes generalists modelling and conclusions derived from prototype tests very questionable. In this article a relatively simple comparative analysis systematic method that allow us to establish some behaviour differences in different kind of prosthesis is presented. The method, applicable in principle to any joint problem, is based on analysing perturbations produced in natural stress states of a bone after insertion of a joint prosthesis and combines numerical analysis using a 3-D finite element model and experimental studies based on photoelastic coating and electric extensometry. The experimental method is applied to compare two total hip prosthesis cement-free femoral stems of different philosophy. One anatomic of new generation, being of oblique setting over cancellous bone and the other madreporique of trochantero-diaphyseal support over cortical bone. (Author) 4 refs

[en] Global Navigation Satellite System (GNSS), and in particular Global Positioning System (GPS) technology provides a powerful tool for studying geodynamic processes. As a consequence of GPS studies, it is now possible to analyze the interaction between tectonic plates in order to evaluate and establish the characteristics of their boundaries. In this study, our main interest is to focus on the time series analysis obtained from observations of GNSS-GPS satellites. Each GPS observation session provides topocentric geodetic coordinates (east, north, elevation) of the permanent stations that constitute the geodetic network established for this purpose. This paper shows a detailed topocentric coordinate time-series study for sites belonging to what we call the SPINA network, which stands for south of the Iberian Peninsula, north of Africa region. The series under study are processed by techniques of relative positioning with respect to the IGS (International GNSS Service) reference station located in Villafranca. These times series have been analyzed using filter processes, harmonic adjustments and wavelets. A surface velocity field is derived from the time series of daily solutions for each station, whose observations span 8 years or longer. This allows us to obtain a horizontal displacement model to show the regional geodynamic main characteristics.

[en] In recent decades, PET scanners have been widely used for diagnosis and treatment monitoring in nuclear medicine. The continuous effort of the scientific community has led to improvements in scanner performance. Total-body PET is one of the latest upgrades in PET scanners. These kinds of scanners are able to scan the whole body of the patient with a single bed position, since the scanner tube is long enough for the patient to fit inside. While these scanners show unprecedented efficiency and extended field-of-view, a drawback is their low spatial resolution compared to dedicated scanners. In order to improve the spatial resolution of specific areas when measuring with a total-body PET scanner, the IRIS group at IFIC-Valencia is developing a probe. The proposed setup of the probe contains a monolithic scintillation crystal and a SiPM. The signal of the probe is read out by a TOFPET2 ASIC from PETsys, which has shown good performance for PET in terms of spatial and time resolutions. Furthermore, the PETsys technology generates a trigger signal that will be used to time synchronise the probe and the scanner. The proof-of-concept of the probe will be tested in a Preclinical Super Argus PET/CT scanner for small animals located at IFIC. Preliminary simulations of the scanner and the probe under ideal conditions show a slight improvement in the position reconstruction compared to the data obtained with the scanner, therefore we expect a considerable improvement when using the probe in a total-body PET scanner. Characterisation tests of the probe have been performed with a ²²Na point-like source, obtaining an energy resolution of 9.09% for the 511 keV energy peak and a temporal resolution of 619 ps after time walk correction. The next step of the project is to test the probe measuring in temporal coincidence with the scanner. Key words: SiPMs / scintillation crystals / molecular imaging / PET/CT / total-body imaging

[en] Highlights: • An improved version of a Compton telescope for hadron therapy is under development. • First characterization, coincidence and imaging tests have been carried out. • Results show a general improvement of the system performance. The IRIS group of IFIC-Valencia is developing a Compton telescope for treatment monitoring in hadron therapy. The system is composed of three detector layers, each of them consisting of a monolithic LaBr${}_3$ scintillator crystal coupled to Silicon Photomultiplier (SiPM) arrays. A first version of the prototype was developed within the European project ENVISION. Tests with point-like sources and in-beam were carried out with successful results, demonstrating the feasibility of the proposed technology. The limitations of the system were also identified. A new version of the prototype is under development with the aim of improving the performance of the telescope detector planes. To this end, the initial tests of a detector plane based on a new SiPM array have been carried out. The first characterization, coincidence and imaging tests with this new version of the detector plane are presented. In addition, the suitability of CeBr${}_3$ scintillator crystals for this application is being investigated.

[en] Compton Cameras are electronically collimated photon imagers suitable for sub-MeV to few MeV gamma-ray detection. Such features are desirable to enable in vivo range verification in hadron therapy, through the detection of secondary Prompt Gammas. A major concern with this technique is the poor image quality obtained when the incoming gamma-ray energy is unknown. Compton Cameras with more than two detector planes (multi-layer Compton Cameras) have been proposed as a solution, given that these devices incorporate more signal sequences of interactions to the conventional two interaction events. In particular, three interaction events convey more spectral information as they allow inferring directly the incident gamma-ray energy. A three-layer Compton Telescope based on continuous Lanthanum (III) Bromide crystals coupled to Silicon Photomultipliers is being developed at the IRIS group of IFIC-Valencia. In a previous work we proposed a spectral reconstruction algorithm for two interaction events based on an analytical model for the formation of the signal. To fully exploit the capabilities of our prototype, we present here an extension of the model for three interaction events. Analytical expressions of the sensitivity and the System Matrix are derived and validated against Monte Carlo simulations. Implemented in a List Mode Maximum Likelihood Expectation Maximization algorithm, the proposed model allows us to obtain four-dimensional (energy and position) images by using exclusively three interaction events. We are able to recover the correct spectrum and spatial distribution of gamma-ray sources when ideal data are employed. However, the uncertainties associated to experimental measurements result in a degradation when real data from complex structures are employed. Incorrect estimation of the incident gamma-ray interaction positions, and missing deposited energy associated with escaping secondaries, have been identified as the causes of such degradation by means of a detailed Monte Carlo study. As expected, our current experimental resolution and efficiency to three interaction events prevents us from correctly recovering complex structures of radioactive sources. However, given the better spectral information conveyed by three interaction events, we expect an improvement of the image quality of conventional Compton imaging when including such events. In this regard, future development includes the incorporation of the model assessed in this work to the two interaction events model in order to allow using simultaneously two and three interaction events in the image reconstruction. (paper)

[en] The Hamamatsu R5912-02Mod photomultiplier tube (PMT) will be used in the DUNE dual-phase module, a 10-kton fiducial volume liquid-argon time-projection chamber, which is one of the four projected far-detector modules of the DUNE long-baseline neutrino experiment. In the DUNE dual-phase module, the liquid argon places high pressure on the photo-detectors located at the bottom of the 14-m cryostat. Four Hamamatsu R5912-02Mod PMTs were tested at 4-bar absolute pressure and cryogenic temperature (in liquid nitrogen) for the first time. No mechanical or electrical damage is reported, validating the use of this PMT model in the DUNE dual-phase module and in other large scale cryogenic liquid detectors. The differences observed in their behavior are expected for the change in the PMT operating temperature.

[en] The TJ-II stellarator, a magnetically confined plasma device, is equipped with a broad range of diagnostics for plasma characterization. These include 4 neutral particle analyzers (NPAs), consisting of two Acord-12's, to perform poloidal measurements, plus a compact NPA, and an Acord-24, these in tangential viewing positions. The Acord-12's were originally equipped with two rows of 6 channels each, one for hydrogen neutrals and the other for deuterium neutrals but were changed to a single row of 12 detectors for hydrogen, the principal working gas in TJ-II. With this upgrade the resultant improved energy resolution spectrum has allowed more reliable ion temperature estimates to be obtained. Here we present the upgrades undertaken and present results to demonstrate the improved performance of this diagnostic

[en] AMIC architecture has been introduced in previous works in order to provide a generic and expandable solution for implementing large number of outputs SiPM array/PMT detectors. The underlying idea in AMIC architecture is to calculate the moments of the detected light distribution in an analog fashion. These moments provide information about energy, x/y position, etc. of the light distribution of the detected event. Moreover this means that a small set of signals contains most of the information of the event, thus reducing the number of channels to be acquired. This paper introduces a new front-end device AMIC2GR which implements the AMIC architecture improving the features of the former integrated devices. Higher bandwidth and filtering coefficient precision along with a lower noise allow to apply some detector enhancements. Inhomogeneity among detector elements throughout the array can be reduced. Depth of interaction measurements can be obtained from the light distribution analysis. Also a common trigger signal can be obtained for the whole detector array. Finally AMIC2GR preamplifier stage close to SiPM output signals optimizes signal to noise ratio, which allows to reduce SiPM gain by using lower operating voltages thus reducing dark noise.

[en] Among the different porous materials, activated carbon (AC) is the most widely used for environmental applications such as gas-phase pollutant removal, gas separation, solvent recovery and water purification, because of its high specific surface area. Commercial activated carbons are generally produced from coals and lignocellulosic materials [1]. Additionally, in the latest years great attention is being focused on the reuse of wastes such as sewage sludges [2,3]. The objective of this study is to find more effective activating procedures to prepare AC from sewage sludge. Both dried sludges from two different WWTP (SL, SB) and their corresponding chars prepared by pyrolysis (SL-P, SB-P) were activated using physical activation (CO₂) and chemical activation (H₃PO₄, NaOH and KOH). As shown in Table 1, pyrolysis of the raw sludges slightly increased the specific surface area, up to 50 m²/g. Acid-washing of the pyrolyzed samples with 5 M HCl removes part of the metal content leading to an increase in the specific surface areas for both SL-PD and SB-PD, with surface areas of 428 m²/g and 188 m²/g, respectively. This simple washing treatment is useful for the development of porous adsorbents, especially in the case of SL derived materials. Our results show that CO₂ physical activation of the pyrolyzed and the HCl-washed samples develops no appreciable porosity in the final materials, under the experimental conditions used. For CO₂ activation, maximum temperatures of 870 C and holding times up to 4 hours in CO₂ (100 ml/min) were used. Chemical activation with H₃PO₄ of the pristine samples and those pyrolyzed was performed at 450 C, a temperature typically used for the activation by H₃PO₄ of lignocellulosic precursors, and using two different H₃PO₄ solutions (30 and 50% wt). These conditions were not either suitable for an efficient porosity development. A detailed study about the influence of several experimental variables in chemical activation with alkaline hydroxides (Na, K) was carried out following three different mixing processes: impregnation (1), physical mixing of the oxide lentils and the precursor (PM), and a variation of this physical mixing method, grinding the activated agent prior to the physical mixing (GPM). The heat-treatment was performed in N₂ at 700 C for one hour. Our results show that the mixing method of the precursor and the hydroxide has an enormous influence in the porosity of the AC. Figure 1 compares the total micropore volume, deduced from N₂ data, of AC prepared from either SL-P or SB-P, using the three methods studied (I, PM and GPM) with a NaOH/precursor ratio 1/1. This figure shows that, for both precursors, the porosity of AC prepared by impregnation (1) and physical mixing (PM) is very similar, and much lower than that obtained when ground hydroxide is used (GPM). By GPM, highly activated carbons were obtained, using an active agent/precursor ratio of 3/1, with an important micro porosity contribution and specific surface areas, up to 0.46 cm³/g and 1224 m²/g respectively for NaOH activation, and up to 0.64 cm³/g and 1686 m²/g respectively for KOH. In this sense, this work remarks the importance of the mixing step during the sewage sludge activation in terms of porosity development, highlighting the interest of grinding the hydroxide. [1] M.A. Lillo-Rodenas et al., Carton 39 (5), 751, 2001. [2] S. Rio et al., Water Science and Technology 49 (1), 139, 2004. [3] M. Martin et al., Carbon 42 (7), 1389, 2004. (authors)