Timing performance of a vacuum phototriode

The official published version of the article can be found at the link below.The timing performance of a vacuum phototriode (VPT) has recently been simulated using SIMION 3D software [1] to develop an electron-optic model [2]. In this work, more precise treatment of the approximation is detailed and comparison is made with corresponding experimental data. The origin of the signals features is investigated and interpreted, affording a deeper understanding into the operation and timing potential of these devices

Studying the time response of a vacuum phototriode and measurement of gamma radiation damage to high voltage capacitors and resistors

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A vacuum phototriodes (VPT) are the photodetectors used in the endcaps of the Electromagnetic Calorimeter of the Compact Muon Solenoid experiment at the Large Hadron Collider at CERN. Software, interfacing with the commercial program “SIMION 3D” was written to allow the simulation of the temporal response of the VPT. Applying Ramo’s Theorem enabled the time development of the VPT signal to be calculated. In order to validate the simulations, experiments were performed using a 60 ps laser pulses (λ = 435 nm) incident on a number of VPT samples. The simulation reproduced the basic features of the operation of the VPT such as gain vs. voltage, and gain vs. magnetic field strength. The simulation also confirmed the need for a fine mesh anode to achieve a useful gain when operating at high magnetic fields. The experimental work represents the first measurements of the time response of a VPT when excited with a very fast light pulse. Both the simulated and experimental response from the VPT were observed to be fast (few ns) and quite complex. Discrepancies between the simulated and experimental signals were partially explained by a SPICE model which includes the VPT interelectrode capacitances and lead inductances. We conclude that the VPT are fast photodetectors with an intrinsic response time of order 1ns for this geometry. The VPT high-voltage filter cards, which operate at 1 kV and in an intense radiation environment, are critical components. A number of commercial off-the-shelf high voltage resistors and capacitors were evaluated at gamma doses up to 345 kGy. No significant change in value or leakage current was observed. As a result of these studies we were able to demonstrate that these inexpensive components were suitable for use in the 3100 filter cards subsequently installed in the CMS apparatus

Simulation of a vacuum phototriode with SIMION 3D

An electron-optic model of a 26 mm diameter vacuum phototriode (VPT) photodetector was developed using SIMION 3D software extended by additional code to simulate secondary emission at the dynode. The predictions of the variation of gain with magnetic field for mesh anodes with 100, 40 and 7 lines per mm and fields from 0 and 4 T are presented. The predicted time development of the signal at 0 T is presented and compared with experimental data obtained by illuminating a production VPT for the electromagnetic endcap calorimeter of CMS with 60 ps laser pulses at a wavelength of 435 nm

Máster INFTEL: Transición de la universidad a la empresa en el campo de las comunicaciones móviles

Las actividades de los estudiantes en la universidad tienen características claramente diferentes a las actividades en una empresa. Al pasar el estudiante de un lugar al otro necesita un periodo de adaptación. Reducir ese periodo de adaptación permite que la persona se integre en la actividad profesional en menos tiempo y de forma más eficaz. Esto es más cierto aún en el ámbito de los teléfonos móviles y los desarrollos informáticos vinculados a ellos, dada su reciente aparición que requiere de una formación especializada. Con este doble enfoque nació el Máster Universitario en Informática aplicada a las Telecomunicaciones Móviles (Máster INFTEL), que alcanza ya la XI edición, habiéndose graduado diez promociones. Con esta experiencia, planteamos en este trabajo hacer un breve recorrido sobre cuál fue su origen, enfoque, resultados alcanzados y plantear las perspectivas futurasUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Studying the time response of a vacuum phototriode and measurement of gamma radiation damage to high voltage capacitors and resistors

A vacuum phototriodes (VPT) are the photodetectors used in the endcaps of the Electromagnetic Calorimeter of the Compact Muon Solenoid experiment at the Large Hadron Collider at CERN. Software, interfacing with the commercial program “SIMION 3D” was written to allow the simulation of the temporal response of the VPT. Applying Ramo’s Theorem enabled the time development of the VPT signal to be calculated. In order to validate the simulations, experiments were performed using a 60 ps laser pulses (λ = 435 nm) incident on a number of VPT samples. The simulation reproduced the basic features of the operation of the VPT such as gain vs. voltage, and gain vs. magnetic field strength. The simulation also confirmed the need for a fine mesh anode to achieve a useful gain when operating at high magnetic fields. The experimental work represents the first measurements of the time response of a VPT when excited with a very fast light pulse. Both the simulated and experimental response from the VPT were observed to be fast (few ns) and quite complex. Discrepancies between the simulated and experimental signals were partially explained by a SPICE model which includes the VPT interelectrode capacitances and lead inductances. We conclude that the VPT are fast photodetectors with an intrinsic response time of order 1ns for this geometry. The VPT high-voltage filter cards, which operate at 1 kV and in an intense radiation environment, are critical components. A number of commercial off-the-shelf high voltage resistors and capacitors were evaluated at gamma doses up to 345 kGy. No significant change in value or leakage current was observed. As a result of these studies we were able to demonstrate that these inexpensive components were suitable for use in the 3100 filter cards subsequently installed in the CMS apparatus.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Relación entre las importaciones de Francia y las exportaciones del Perú de conchas de abanico, en el periodo 2011 - 2020. El caso de la empresa Acuapesca S.A.C.

En la presente tesis de investigación, se tuvo como principal finalidad el conocer cómo la concha de abanico peruana ha evolucionado a través del Comercio Internacional en el periodo de 2011 al 2020, teniendo a Perú y Francia como eje central, ambos siendo el punto de origen y destino respectivamente. El objetivo discutido fue determinar cómo las importaciones de Francia de conchas de abanico se correlacionan con las exportaciones de Perú a Francia de conchas de abanico, es decir, el nivel de significancia que poseen ambas variables de desarrollo en simultáneo, buscándose responder cómo afecta y desarrolla la oferta exportable peruana de concha de abanico y sus aspectos más importantes sobre su atractivo al mercado internacional. Para la cual se contó con la elaboración de matrices de recolección de datos, cuya misión fue el poder recolectar datos estadísticos históricos sobre el movimiento comercial de la concha de abanico entre Perú y Francia en un periodo determinado de 10 años (2011-2020), además de contar con el testimonio de una empresa netamente exportadora de conchas de abanico, Acuapesca SAC., enriqueciéndose así la investigación, logrando contrastarse la información estadística con las experiencias de la empresa exportadora, la cual supera los 20 años desde sus inicios en la exportación hasta la actualidad. Los resultados señalaron que, las importaciones de Francia y las exportaciones de Perú de concha de abanico se encuentran correlacionadas con un muy alto nivel y significancia, habiéndose tomado como factores de participación el precio de importación de Francia, los países proveedores con TLC y los requerimientos sanitarios desde origen a destino, poniéndose en evidencia que el mercado francés es muy exigente y cotizado a nivel internacional, y que la oferta exportable peruana a pesar de ser atractiva para el mercado debe mejorar sus prácticas para tener una mejor imagen competitiva, desde los procesos productivos, de distribución y finalmente de difusión.Campus Lima Centr

Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered

Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented