X-ray propagation through hollow channel: PolyCAD - a ray tracing code (1)

A new CAD program, PolyCAD, designed for X-ray photon tracing in polycapillary optics is described. To understand the PolyCAD code and its results, the theoretical basis of X-ray transmission by a single cylindrical channel (monocapillary) is discussed first. Then the simplest cases of cylindrically and conically shaped polycapillary optics are examined. PolyCAD allows any type of X-ray source to be used: an X-ray tube of finite beam dimensions or an astrophysical object can be simulated in combination with the polycapillary optics. The radiation distribution images formed on a screen located at various focal distances are discussed. The good agreement of some of the PolyCAD results with those reported in earlier papers validate the code. This is the first paper of a series dedicated to the development of an exhaustive CAD program, work is in progress to develop the code to include other polycapillary-optics shapes, such as semi-lenses and full-lenses.Comment: Submitted to Applied Optic

Molybdenum oxides coatings for high demanding accelerator components

Large electric gradients are required for a variety of new applications, notably including the extreme high brightness electron sources for X-ray free electron lasers (FELs), radio-frequency (RF) photo-injectors, industrial and medical accelerators, and linear accelerators for particle physics colliders. In the framework of the INFN-LNF, SLAC (USA), KEK (Japan), UCLA (Los Angeles) collaboration, the Frascati National Laboratories (LNF) are involved in the modelling, development, and testing of RF structures devoted to particles acceleration by high gradient electric fields of particles through metal devices. In order to improve the maximum sustainable gradients in normal-conducting RF-accelerating structures, both the RF breakdown and dark current should be minimized. To this purpose, studying new materials as well as manufacturing techniques are mandatory to identify better solutions to such extremely requested applications. In this contribution, we discuss the possibility of using a dedicated coating on a solid copper sample (and other metals) with a relatively thick film to improve and optimize breakdown performances and to minimize the dark current. We present here the first characterization of MoO3 films deposited on copper by pulsed-laser deposition (PLD)

Mu2e Crystal Calorimeter Readout Electronics: Design and Characterisation

The Mu2e experiment at Fermi National Accelerator Laboratory will search for the charged-lepton flavour-violating neutrinoless conversion of negative muons into electrons in the Coulomb field of an Al nucleus. The conversion electron with a monoenergetic 104.967 MeV signature will be identified by a complementary measurement carried out by a high-resolution tracker and an electromagnetic calorimeter, improving by four orders of magnitude the current single-event sensitivity. The calorimeter—composed of 1348 pure CsI crystals arranged in two annular disks—has a high granularity, 10% energy resolution and 500 ps timing resolution for 100 MeV electrons. The readout, based on large-area UV-extended SiPMs, features a fully custom readout chain, from the analogue front-end electronics to the digitisation boards. The readout electronics design was validated for operation in vacuum and under magnetic fields. An extensive radiation hardness certification campaign certified the FEE design for doses up to 100 krad and 1012 n1MeVeq/cm2 and for single-event effects. A final vertical slice test on the final readout chain was carried out with cosmic rays on a large-scale calorimeter prototype

The Mu2e Crystal Calorimeter: An Overview

The Mu2e experiment at Fermilab will search for the standard model-forbidden, charged lepton flavour-violating conversion of a negative muon into an electron in the field of an aluminium nucleus. The distinctive signal signature is represented by a mono-energetic electron with an energy near the muon's rest mass. The experiment aims to improve the current single-event sensitivity by four orders of magnitude by means of a high-intensity pulsed muon beam and a high-precision tracking system. The electromagnetic calorimeter complements the tracker by providing high rejection power in muon to electron identification and a seed for track reconstruction while working in vacuum in presence of a 1 T axial magnetic field and in a harsh radiation environment. For 100 MeV electrons, the calorimeter should achieve: (a) a time resolution better than 0.5 ns, (b) an energy resolution <10%, and (c) a position resolution of 1 cm. The calorimeter design consists of two disks, each loaded with 674 undoped CsI crystals read out by two large-area arrays of UV-extended SiPMs and custom analogue and digital electronics. We describe here the status of construction for all calorimeter components and the performance measurements conducted on the large-sized prototype with electron beams and minimum ionizing particles at a cosmic ray test stand. A discussion of the calorimeter's engineering aspects and the on-going assembly is also reported

Metodologie per la rivelazione e il riconoscimento di impurezze solide mediante sorgenti X : caratterizzazione di materiali complessi con applicazione al caso della matrice solida dell'acqua

I ghiacciai sono un naturale sistema di immagazinamento di dati climatologici, che consente attraverso le precipitazioni di raccogliere in serie temporalmente ordinate le particelle provenienti dalla circolazione atmosferica. A questo proposito, l'identificazione di polvere mineralogia svolge un ruolo chiave. In questa tesi, partecipo ad un esperimento preliminare di spettroscopia di assorbimento X (XAS) di minerali di polvere estratte da carote di ghiaccio antartico e alpino sulla soglia del Fe. Nella tesi viene descritta una camera sperimentale da alto vuoto, progettata e realizzata per lo studio della fluorescenza e assorbimento X anche ad incidenza radente. Presso lo Stanford Synchrotron Radiation Lightsource (SSRL), sono state effettuate misure di fluorescenza e assorbimento X di materiali a bassissime concentrazioni. I risultati mostrano che questa tecnica sperimentale permette il riconoscendo di inclusioni di ferro (dell'ordine di 1-10 ug) nel particolato insolubile . Inoltre, presso i Laboratori Nazionali di Frascati dell'INFN, con il mio contributo è stato progettato, sviluppato e realizzato, un sistema di micro-spettroscopia, discusso nella tesi, al fine di raggiungere una mappatura di micro-fluorescente X (uXRF) con una risoluzione spaziale di chi 100x100 um. Questo apparecchio permette anche di effettuare "Imaging" (con radiazione non coerente), per mezzo di un ingrandimento del settore in analisi mediante lenti rifrazione (CRL).Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this thesis, I partecipate in preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and X-Ray Fluorescence (normal and total-reflection configuration) and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Lightsource. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 ug range. Moreover, at the "Laboratori Nazionali di Frascati" of INFN, with my contribution has been designed, developed and done, a system of micro-spectroscopy, discussed in the thesis, in order to achieve a mapping in micro-fluorescent X (uXRF) with a spatial resolution of about 100x100 um. This apparatus allows also to carry "imaging" (with radiation not coherent), by means of a magnification of the area in analysis by means of lenses refractive (CRL)

Metodologie per la rivelazione e il riconoscimento di impurezze solide mediante sorgenti X : caratterizzazione di materiali complessi con applicazione al caso della matrice solida dell'acqua

I ghiacciai sono un naturale sistema di immagazinamento di dati climatologici, che consente attraverso le precipitazioni di raccogliere in serie temporalmente ordinate le particelle provenienti dalla circolazione atmosferica. A questo proposito, l'identificazione di polvere mineralogia svolge un ruolo chiave. In questa tesi, partecipo ad un esperimento preliminare di spettroscopia di assorbimento X (XAS) di minerali di polvere estratte da carote di ghiaccio antartico e alpino sulla soglia del Fe. Nella tesi viene descritta una camera sperimentale da alto vuoto, progettata e realizzata per lo studio della fluorescenza e assorbimento X anche ad incidenza radente. Presso lo Stanford Synchrotron Radiation Lightsource (SSRL), sono state effettuate misure di fluorescenza e assorbimento X di materiali a bassissime concentrazioni. I risultati mostrano che questa tecnica sperimentale permette il riconoscendo di inclusioni di ferro (dell'ordine di 1-10 ug) nel particolato insolubile . Inoltre, presso i Laboratori Nazionali di Frascati dell'INFN, con il mio contributo è stato progettato, sviluppato e realizzato, un sistema di micro-spettroscopia, discusso nella tesi, al fine di raggiungere una mappatura di micro-fluorescente X (uXRF) con una risoluzione spaziale di chi 100x100 um. Questo apparecchio permette anche di effettuare "Imaging" (con radiazione non coerente), per mezzo di un ingrandimento del settore in analisi mediante lenti rifrazione (CRL).Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this thesis, I partecipate in preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and X-Ray Fluorescence (normal and total-reflection configuration) and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Lightsource. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 ug range. Moreover, at the "Laboratori Nazionali di Frascati" of INFN, with my contribution has been designed, developed and done, a system of micro-spectroscopy, discussed in the thesis, in order to achieve a mapping in micro-fluorescent X (uXRF) with a spatial resolution of about 100x100 um. This apparatus allows also to carry "imaging" (with radiation not coherent), by means of a magnification of the area in analysis by means of lenses refractive (CRL)