Quality Control (QC) parameters for an X-ray tube depend strongly on the accurate assessment of the primary spectrum. In previous works, a methodology to assess primary spectrum using a Compton spectrometry technique has been analyzed. This methodology consists in the use of a Monte Carlo (MC) model, by means of the MCNP5 code, to reproduce the physical phenomena involving the interaction of photons and electrons with the Compton spectrometer and a High-Purity Germanium detector (HPGe). The relation between the Pulse Height Distribution (PHD) recorded by the detector and the primary beam X-ray spectrum is defined by a Response matrix. To estimate the primary spectrum knowing the PHD is necessary to obtain the inverse of the Response matrix. This is an inefficient task using traditional methods because this matrix is ill-conditioned. In this paper, the Tikhonov method has been used to obtain an approximation to this matrix. This unfolding mathematical tool requires a sensitivity study to know the effect of the truncation process. This methodology can be very useful for QC of X-ray tubes used in radiodiagnostic.
An accurate knowledge of the photon spectra emitted by X-ray tubes in radiodiagnostic is essential to better estimate the imparted dose to patients and to improve the quality image obtained with these devices. However, it is difficult to measure the energy spectrum of these tubes due to the pile up effect produced by the high fluence of X-ray beams. In this work, it is proposed the use of a flat panel detector together with a PMMA wedge to obtain a dose distribution for different high voltages. The relation between the dose curve recorded by the flat panel and the primary beam X-ray spectrum is defined by a Response matrix. The MCNP5 code based on the Monte Carlo method has been used to simulate the actual experimental acquisition including the X-ray tube, the PMMA wedge and a flat panel. A Response matrix has been obtained by means of different monochromatic beams. Knowing the dose distribution for a given conditions and the Response matrix, the primary spectrum can be obtained. The Modified Truncated Singular Value Decomposition (MTSVD) method has been applied to unfold primary spectra using Matlab © algorithms. Unfolded spectra are compared with theoretical X-ray spectra obtained from IPEM 78 catalogue report. Results show that the hybrid technique -experimental-Monte Carlo method-could represent a valid tool in order to complement the Quality Control of X-ray tubes in the radiodiagnostic energy range.
The inspections performed in Davis Besse and in the South Texas Project Unit-I reactors pointed out safety issues regarding the structural integrity of the Pressure Vessel (PV). In these inspections, two anomalies were found: a wall thinning and degradation in the PV upper head of the Davis Besse reactor and a small amount of residue around of two instrument-tube penetration nozzles located in the PV lower plenum of the South Texas Project Unit-I reactor. The evolution of these defects could have resulted in Small Break Loss-Of-Coolant Accidents (SBLOCA) if they had not been detected in time. In this frame, the OECD/NEA considered the necessity to simulate these accidental sequences in the OECD/NEA ROSA Project using the Large Scale Test Facility (LSTF). This work is focused on simulating different hypothetical accidental scenarios in the PV using the thermal-hydraulic code TRACE5. These simulations allow studying the break localization influence in the transient and the effectiveness of the accident management (AM) actions considered mitigating the consequences of these hypothetical accidental scenarios.
Current degrees belonging to the European Higher Education One of these competences is the "knowledge of contemporary issues", which refers to the need for students to understand the political, social, legal and environmental issues and values, as defined by the UPV. This competence also takes into account the mechanism of expansion and dissemination of knowledge.In this paper a preliminary experience carried out in the Mechanical Vibrations course is described. An activity framed in a laboratory session has been designed to this end, where this competence is introduced related to the contents of the subject. The results of this experience indicate that the training of the competence "knowledge of contemporary issues" contributes to improve learning in the subject.
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