P. Dervan

A double-sided, shield-less stave prototype for the ATLAS Upgrade strip tracker for the High Luminosity LHC

A detailed description of the integration structures for the barrel region of the silicon strips tracker of the ATLAS Phase-II upgrade for the upgrade of the Large Hadron Collider, the so-called High Luminosity LHC (HL-LHC), is presented. This paper focuses on one of the latest demonstrator prototypes recently assembled, with numerous unique features. It consists of a shortened, shield-less, and double sided stave, with two candidate power distributions implemented. Thermal and electrical performances of the prototype are presented, as well as a description of the assembly procedures and tools.

Scanning facility to irradiate mechanical structures for the LHC upgrade programme

The existing luminosity of the LHC will be increased in stages to a factor of 10 above its current level (HL-LHC) by 2022. This planned increase in luminosity results in significantly higher levels of radiation inside the proposed ATLAS Upgrade detector. This means existing detector technologies together with new components and materials need to be re-examined to evaluate their performance and durability at these higher fluences. Of particular interest is the effect of radiation on the upgraded ATLAS tracker. To study these effects a new ATLAS irradiation scanning facility has been developed using the Medical Physics Cyclotron at the University of Birmingham. The intense cyclotron beams allow irradiated samples to receive in minutes fluences corresponding to years of operation at the HL-LHC. Since commissioning in early 2013, this facility has been used to irradiate silicon sensors, optical components and carbon fibre sandwiches for the ATLAS upgrade programme. Irradiations of silicon sensors and passive materials can be carried out in a temperature controlled cold box which moves continuously through the homogenous beamspot. This movement is provided by a pre-configured XY-axis cartesian robot system (scanning system). This paper reviews the design, development, commissioning, performance results and future plans of the irradiation facility, fully operational since 2013.

A double-sided silicon micro-strip Super-Module for the ATLAS Inner Detector upgrade in the High-Luminosity LHC

The ATLAS experiment is a general purpose detector aiming to fully exploit the discovery potential of the Large Hadron Collider (LHC) at CERN. It is foreseen that after several years of successful data-taking, the LHC physics programme will be extended in the so-called High-Luminosity LHC, where the instantaneous luminosity will be increased up to 5 × 1034 cm−2 s−1. For ATLAS, an upgrade scenario will imply the complete replacement of its internal tracker, as the existing detector will not provide the required performance due to the cumulated radiation damage and the increase in the detector occupancy. The current baseline layout for the new ATLAS tracker is an all-silicon-based detector, with pixel sensors in the inner layers and silicon micro-strip detectors at intermediate and outer radii. The super-module is an integration concept proposed for the strip region of the future ATLAS tracker, where double-sided stereo silicon micro-strip modules are assembled into a low-mass local support structure. An electrical super-module prototype for eight double-sided strip modules has been constructed. The aim is to exercise the multi-module readout chain and to investigate the noise performance of such a system. In this paper, the main components of the current super-module prototype are described and its electrical performance is presented in detail.

Silicon strip detectors for the ATLAS HL-LHC upgrade

While the Large Hadron Collider (LHC) at CERN is continuing to deliver a steadily increasing luminosity to the experiments, plans for an upgraded machine called the High Luminosity-LHC (HL-LHC) are progressing. The upgrade is foreseen to increase the LHC design integrated luminosity by a factor ten. The ATLAS experiment will need to build a new tracker for HL-LHC operation, which needs to be suited to the harsh HL-LHC conditions in terms of particle rates and radiation doses. In order to cope with the increase in pile-up backgrounds at the higher luminosity, an all-silicon detector is being designed. To successfully face the increased radiation dose and occupancy, a new generation of extremely radiation hard silicon detectors has been designed. This paper, will give an overview of the ATLAS tracker upgrade project, in particular focusing on the crucial innermost silicon strip layers. Results from a wide range of irradiated silicon detectors will be presented, and layout concepts for lightweight yet mechanically very rigid detector modules with high service integration will be shown. We will draw conclusions on what type and design of strip detectors to employ for the upgrades of the tracking layers in the HL-LHC upgrades of LHC experiments.

Recent results and experience with the Birmingham MC40 irradiation facility

Operational experience with the recently upgraded irradiation facility at the University of Birmingham is presented. This is based around the high intensity area of the MC40 medical cyclotron providing proton energies between 3 and 38 MeV and currents ranging from tens of fA to μA. Accurate dosimetry for displacement damage and total ionizing dose, using a combination of techniques, is offered. Irradiations are carried out in a temperature controlled chamber that can be scanned through the beam, with the possibility for the devices to be biased, clocked, and read-out. Fluence up to several 1016 1 MeV neq/cm2 and GRad ionizing dose can be delivered within a day.