Bonding of the Inner Tracker Silicon Microstrip Modules

Microbonding of the CMS Tracker Inner Barrel (TIB) and Tracker Inner Disks (TID) modules was shared among six different Italian Institutes. The organization devised and the infrastructure deployed to handle this task is illustrated. Microbonding specifications and procedures for the different types of TIB and TID modules are given. The tooling specially designed and developed for these types of modules is described. Experience of production is presented. Attained production rates are given. An analysis of the microbonding quality achieved is presented, based on bond strengths measured in sample bond pull tests as well as on rates of bonding failures. Italian Bonding Centers routinely performed well above minimum specifications and a very low global introduced failure rate, at the strip level, of only $\sim$0.015 \% is observed

Assembly of the Inner Tracker Silicon Microstrip Modules

This note describes the organization of the mechanical assembly of the nearly 4000 silicon microstrip modules that were constructed in Italy for the Inner Tracker of the CMS experiment. The customization and the calibration of the robotic system adopted by the CMS Tracker community, starting from a general pilot project realized at CERN, is described. The step-by-step assembly procedure is illustrated in detail. Finally, the results for the mechanical precision of all assembled modules are reported

Monte Carlo calculation of age-dependent calibration factors for in-vivo monitoring of 131I in thyroid

International audienceThis work summarizes the results of Monte Carlo simulations for several detectors and voxel phantoms representing different age groups that have been performed to investigate the variation of the detection efficiency with distance, age and thyroid volume. Age-dependent correction factors to be applied to the adult calibration factor have been derived and can be used when calibration factors for children are not available. Moreover, the influence of elapsed time since intake has been investigated taking into account the iodine biokinetics

In vivo monitoring intercomparisons: the CAThyMARA and EURADOS experiences

International audienceThe CAThyMARA project aimed at improving child thyroid monitoring in the event of accidental release. Among other topics an intercomparison of thyroid monitoring was carried out for spectroscopic and non-spectroscopic devices. For that purpose, thyroid phantoms corresponding to the adult, 10 and 5 years-old children were circulated in Europe. The activities were unknown for participants, for spectroscopic devices 133Ba was used as a substitute of 131I while a mixture of 137Cs and 133Ba and a silver filter were used for non-spectroscopic devices. A total of 72 devices have been tested, of which 43 non-spectroscopic devices. The results are encouraging, for example, 11/38 of non-spectroscopic devices were out of the ISO criteria in the case of the 5 years-old case. While in vivo intercomparision usually focused on spectrometers it was shown that dosemeters or count-rate meters performed as well as spectroscopic devices. The EURADOS working group 6 (computational dosimetry) and 7 (internal dosimetry) have also carried out intercomparisons of efficiency measurements and Monte-Carlo efficiency calculations. Between 2007 and 2016 the cases of 241Am in two different leg phantoms and in three skulls have been considered as well as the case of enriched uranium in lungs. In each case most of participants managed to compute the counting efficiency, eventually after interaction with the organizers. Each of this exercise revealed specific problems, for example error in the activity certificate or measurements at the wrong positions

Child and adult thyroid monitoring after a reactor accident (CAThyMARA): Technical recommendations and remaining gaps

International audienceFollowing a severe nuclear reactor accident large amounts of radioactive iodine are released in the atmosphere. Health consequences estimation for the affected population is based on the dose assessment which can be derived from in vivo measurements. Since the uptake of radioactive iodine increases the thyroid cancer risk of children it is of particular interest to dispose of technical recommendations on thyroid monitoring, particularly for children.This paper summarizes recommendations that have been issued by a group of European radiation protection specialists during the CAThyMARA project. It covers technical aspects such as the choice of instruments, the calibration process, the measurement preparedness, the dose assessment and communication issues. This paper also discusses remaining gaps and serves as an introduction to other papers of this special issue

Test of the Inner Tracker: Silicon Microstrip Modules

The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented

Track Reconstruction with Cosmic Ray Data at the Tracker Integration Facility

The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007. As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field. Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15\,\% of the final silicon strip detector, and over 4.7~million events were recorded. This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses

Strategies and performance of the CMS silicon tracker alignment during LHC Run 2

The strategies for and the performance of the CMS silicon tracking system alignment during the 2015–2018 data-taking period of the LHC are described. The alignment procedures during and after data taking are explained. Alignment scenarios are also derived for use in the simulation of the detector response. Systematic effects, related to intrinsic symmetries of the alignment task or to external constraints, are discussed and illustrated for different scenarios

Precision measurement of the structure of the CMS inner tracking system using nuclear interactions

The structure of the CMS inner tracking system has been studied using nuclear interactions of hadrons striking its material. Data from proton-proton collisions at a center-of-mass energy of 13 TeV recorded in 2015 at the LHC are used to reconstruct millions of secondary vertices from these nuclear interactions. Precise positions of the beam pipe and the inner tracking system elements, such as the pixel detector support tube, and barrel pixel detector inner shield and support rails, are determined using these vertices. These measurements are important for detector simulations, detector upgrades, and to identify any changes in the positions of inactive elements