Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

A silicon photomultiplier (SiPM) array has been developed at FBK-irst having 32 channels and a dimension of 8.0 x 1.1 mm^2. Each 250 um wide channel is subdivided into 5 x 22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved

On the basic mechanism of Pixelized Photon Detectors

A Pixelized Photon Detector (PPD) is a generic name for the semiconductor devices operated in the Geiger-mode, such as Silicon PhotoMultiplier and Multi-Pixel Photon Counter, which has high photon counting capability. While the internal mechanisms of the PPD have been intensively studied in recent years, the existing models do not include the avalanche process. We have simulated the multiplication and quenching of the avalanche process and have succeeded in reproducing the output waveform of the PPD. Furthermore our model predicts the existence of dead-time in the PPD which has never been numerically predicted. For serching the dead-time, we also have developed waveform analysis method using deconvolution which has the potential to distinguish neibouring pulses precisely. In this paper, we discuss our improved model and waveform analysis method.Comment: 4pages, 5figures, To appear in the proceedings of 5th International Conference on New Developments in Photodetection (NDIP08), Aix-les-Bains, France, 15-20 Jun 200

Witten index and phase diagram of compactified N=1 supersymmetric Yang-Mills theory on the lattice

Owing to confinement, the fundamental particles of N=1 Supersymmetric Yang-Mills (SYM) theory, gluons and gluinos, appear only in colourless bound states at zero temperature. Compactifying the Euclidean time dimension with periodic boundary conditions for fermions preserves supersymmetry, and confinement is predicted to persist independently of the length of the compactified dimension. This scenario can be tested non-perturbatively with Monte-Carlo simulations on a lattice. SUSY is, however, broken on the lattice and can be recovered only in the continuum limit. The partition function of compactified N=1 SYM theory with periodic fermion boundary conditions corresponds to the Witten index. Therefore it can be used to test whether supersymmetry is realized on the lattice. Results of our recent numerical simulations are presented, supporting the disappearance of the deconfinement transition in the supersymmetric limit and the restoration of SUSY at low energies.Comment: 7 pages, 3 figures, Proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe International Conference Center, Kobe, Japa

La Segunda Internacional en su relación con Marx y Engels a propósito de la cuestión nacional (1889-1914)

La interpretació que sobre les nacions van poder oferir Marx i Engels va restar inconclusa, quedant lluny de veure's cristal·litzada en fórmules analítiques precises a partir de les quals fos possible combinar la qüestió nacional en un pla d'acció revolucionari. Tanmateix, aquests primers esbossos sobre les nacions van ser recollits i ampliats pels socialistes de la Segona Internacional. L'objectiu d'aquest treball és recuperar analíticament les primeres interpretacions que van sorgir en el si del socialisme europeu a la fi del segle XIX i començaments del segle XX al voltant del procés de conformació d'aquella nova relació dialèctica intervinguda entre la lluita nacional i la lluita de classes. Amb aquest propòsit seran abordades les produccions intel·lectuals més destacades del període, la qual cosa permetrà actualitzar des d'una perspectiva històrica el nucli dels intensos debats experimentats pel marxisme europeu que van aconseguir el seu punt d'ebullició fa exactament un segle al voltant del sorgiment de les nacions i les nacionalitats i les seves possibles vinculacions amb els plans per aconseguir l'emancipació dels treballadors.Marx and Engels’ interpretation of the nations was left inconclusive, thus remaining far from crystallising into precise analytic formulas from which it would be possible to combine the national question into a revolutionary action plan. Nevertheless, these first sketches around the nations were compiled and expanded on by the Second International socialists. The aim of this paper is to analytically recover the first interpretations that emerged within the European socialism in the late nineteenth century and early twentieth century around the process of forming this new mediated dialectical relationship between the national struggle and class struggle. To this purpose, I will address the most salient intellectual productions of the period, which will update from a historical perspective the core of the intense debates experienced by the European Marxism, which reached their boiling point exactly a century ago during the rise of nations and nationalities and their possible links with plans to achieve the emancipation of workers.La interpretación que sobre las naciones pudieron brindar Marx y Engels resultó inconclusa, quedando lejos de verse cristalizada en fórmulas analíticas precisas a partir de las cuales fuera posible combinar la cuestión nacional en un plan de acción revolucionario. No obstante, estos primeros bocetos en torno de las naciones fueron recogidos y ampliados por los socialistas de la Segunda Internacional. El objetivo de este trabajo es recuperar analíticamente las primeras interpretaciones que emergieron en el seno del socialismo europeo a finales del siglo XIX y comienzos del siglo XX alrededor del proceso de conformación de aquella novedosa relación dialéctica mediada entre la lucha nacional y la lucha de clases. Con este propósito serán abordadas las producciones intelectuales más salientes del período, lo que permitirá actualizar desde una perspectiva histórica el núcleo de los intensos debates experimentados por el marxismo europeo que alcanzaron su punto de ebullición hace exactamente un siglo alrededor del surgimiento de las naciones y las nacionalidades y sus posibles vinculaciones con los planes para alcanzar la emancipación de los trabajadores

L’ASDI e le politiche di governance per lo sviluppo per il Distretto della Sedia

Associazione per lo Sviluppo del Distretto della Sedia (ASDI Sedia

A Scintillating Fiber Tracker With SiPM Readout

We present a prototype for the first tracking detector consisting of 250 micron thin scintillating fibers and silicon photomultiplier (SiPM) arrays. The detector has a modular design, each module consists of a mechanical support structure of 10mm Rohacell foam between two 100 micron thin carbon fiber skins. Five layers of scintillating fibers are glued to both top and bottom of the support structure. SiPM arrays with a channel pitch of 250 micron are placed in front of the fibers. We show the results of the first module prototype using multiclad fibers of types Bicron BCF-20 and Kuraray SCSF-81M that were read out by novel 32-channel SiPM arrays from FBK-irst/INFN Perugia as well as 32-channel SiPM arrays produced by Hamamatsu. A spatial resolution of 88 micron +/- 6 micron at an average yield of 10 detected photons per minimal ionizig particle has been achieved.Comment: 5 pages, 7 figures, submitted as proceedings to the 11th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD08

Supermultiplets of the N=1 supersymmetric Yang-Mills theory in the continuum limit

The spectrum of N=1 supersymmetric Yang-Mills theory, calculated on the lattice, is presented. The masses have been determined on three different lattice spacings and extrapolated towards vanishing gluino mass. We present the extrapolation to the continuum limit which is consistent with the formation of degenerate supermultiplets.Comment: 7 pages, 4 figures; Proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe International Conference Center, Kobe, Japa