ATLAS IBL Pixel Upgrade

During Run 1 of the Large Hadron Collider (LHC), the ATLAS Pixel Detector has shown excellent performance. The ATLAS collaboration took advantage of the first long shutdown of the LHC during 2013 and 2014 and extracted the ATLAS Pixel Detector from the experiment, brought it to surface and maintained the services. This included the installation of new service quarter panels, the repair of cables, and the installation of the new Diamond Beam Monitor (DBM). Additionally, a completely new innermost pixel detector layer, the Insertable B-Layer (IBL), was constructed and installed in May 2014 between a new smaller beam pipe and the existing Pixel Detector. With a radius of 3.3cm the IBL is located extremely close to the interaction point. Therefore, a new readout chip and two new sensor technologies (planar and 3D) are used in the IBL. In order to achieve best possible physics performance the material budget was improved with respect to the existing Pixel Detector. This is realized using lightweight staves for mechanical support and a CO2 based cooling system.This paper describes the improvements achieved during the maintenance of the existing Pixel Detector as well as the performance of the IBL during the construction and commissioning phase. Additionally, first results obtained during the LHC Run 2 demonstrating the distinguished tracking performance of the new Four Layer ATLAS Pixel Detector are presented.

The ATLAS collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have necessitated the development of new radiation hard pixel sensor technologies and a new front-end readout chip, called the FE-I4. Planar pixel sensors and 3D pixel sensors have been investigated to equip this new pixel layer, and prototype modules using the FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test results are presented, including charge collection efficiency, tracking efficiency and charge sharing.

The ATLAS Insertable B-Layer (IBL) is the innermost layer of pixel detectors, and was installed in May 2014 at a radius of 3.3 cm from the beam axis, between the existing Pixel detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and occupancy, is the first large scale application of 3D sensors and CMOS 130 nm technology. The IBL detector construction was completed within about two years (2012 – 2014), and the key features and challenges met during the IBL project are presented, as well as its commissioning and operational experience at the LHC.

The phase 1 upgrade of the ATLAS [1] pixel detector will be done by inserting a fourth pixel layer together with a new beampipe into the recent three layer detector. This new detector, the Insertable B-Layer (IBL) should be integrated into the recent pixel system with as few changes in services as possible, but deliver some advantages over the recent system. One of those advantages will be a new data transmission link from the detector modules to the off-detector electronics, requiring a re-design of the electro-optical converters on the off-detector side. First ideas of how to implement those, together with some ideas to reduce cost by increasing the systems throughput are discussed.

During the first LHC long shutdown (2013/14) a new innermost pixel layer will be added to the present ATLAS Pixel Detector. The Insertable B-Layer (IBL) is a high-reliability, ultra light and radiation hard Pixel Detector assembled with 3D n-in-p and planar n-in-n pixel sensors. Facing the effects of increased luminosity and radiation damage, IBL is expected to improve the b-tagging efficiency, help with pattern recognition performance and add tracking precision with respect to the current detector. Single and double chip modules are loaded on local mechanical support, in the form of 14 staves arranged in cylindrical barrel around the beam pipe. The production of the modules has already started, aiming for a total production of 24 staves including spares. Systematic Quality Assurance (QA) and Quality Control (QC) plans concerning modules, staves and flex from production to final assembly have been put in place. QA is performed in several collaborating institutes and final validation before installation in the ATLAS experiment will be carried out at CERN. Dedicated set-ups have been constructed in order to perform the full chain of QAlQC tests on the production staves. A CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> cooling system is used to cool the pixel modules down to -35°C and an electronic chain similar to the final one has been developed. Furthermore a linear motion system carrying two 241 Am sources with an activity of 41 MBq each is mounted over the stave in order to perform a final characterization of the sensor's performance. The realization of source scans on the 24 production staves permits to analyze the response of sensors to radiation, to easily identify dead pixels, and to provide data for an eventual re-calibration of the charge calibration. The setup and first results obtained on prototype staves are described in detail.

FE-I4 is the new ATLAS pixel readout chip for the upgraded ATLAS pixel detector. Designed in a CMOS 130 nm feature size process, the IC is able to withstand higher radiation levels compared to the present generation of ATLAS pixel Front-End FE-I3, and can also cope with higher hit rate. It is thus suitable for intermediate radii pixel detector layers in the High Luminosity LHC environment, but also for the inserted layer at 3.3 cm known as the 'Insertable B-Layer' project (IBL), at a shorter timescale. In this paper, an introduction to the FE-I4 will be given, focusing on test results from the first full size FE-I4A prototype which has been available since fall 2010. The IBL project will be introduced, with particular emphasis on the FE-I4-based module concept.

A multi-channel PCI express readout board for fast readout of large pixel detectors

Silicon Sensor Technologies for the ATLAS IBL Upgrade

Optical link ASICs for LHC upgrades

Commissioning of the read-out driver (ROD) card for the ATLAS IBL detector and upgrade studies for the pixel Layers 1 and 2

The High Voltage CMOS (HV-CMOS) sensors are extensively investigated by the ATLAS collaboration for the High-Luminosity LHC (HL-LHC) upgrade of the Inner Tracker (ITk) detector. The HV-CMOS technology is a commercial integrated circuit process with the advantages of monolithic readout and fast charge collection. A front-end test platform of CaRIBOu (Control and Readout Itk BOard) and a testbeam Telescope based on the ATLAS IBL (Insertable B-Layer) silicon pixel modules, have been developed for the HV-CMOS sensor study and characterization in testbeam experiments. The Front-End LInk eXchange (FELIX) system is a new approach to function as the gateway between detector front-end electronics and the commodity switched network in the ATLAS upgrade. A FELIX based readout system has been developed for both the CaRIBOu and the testbeam Telescope. It has been deployed successfully in the testbeam at the CERN SPS H8 beamline in August 2017. The test results show that the readout system is capable of sensor calibration and readout of a high-density pixel detector with high trigger rate in testbeam experiments.

The Compact Muon Solenoid (CMS) is a general purpose detector at the Large Hadron Collider (LHC). The LHC luminosity is constantly increased through upgrades of the accel- erator and its injection chain. Two major upgrades will take place in the next years. The rst upgrade involves the LHC injector chain and allows the collider to achieve a luminosity of about 2 10 34 cm-2 s-1 A further upgrade of the LHC foreseen for 2025 will boost its luminosity to 5 10 34 cm-2 s1. As a consequence of the increased luminosity, the detectors need to be upgraded. In particular, the CMS pixel detector will undergo two upgrades in the next years. The rst upgrade (phase I) consists in the substitution of the current pixel detector in winter 2016/2017. The upgraded pixel detector will implement new readout elec- tronics that allow ecient data taking up to a luminosity of 2 10 34 cm-2s-1,twice as much as the LHC design luminosity. The modules that will constitute the upgraded detector are being produced at dierent institutes. Hamburg (University and DESY) is responsible for the production of 350 pixel modules. The second upgrade (phase II) of the pixel detector is foreseen for 2025. The innermost pixel layer of the upgraded detector will accumulate a radiation damage corresponding to an equivalent uence of eq = 2 10 16 cm-2 and a dose of 10 MGy after an integrated luminosity of 3000 fb-1. Several groups are investigating sensor designs and congurations able to withstand such high doses and uences. This work is divided into two parts related to important aspects of the upgrades of the CMS pixel detector. For the phase I upgrade, a setup has been developed to provide an absolute energy calibration of the pixel modules that will constitute the detector. The cali- bration is obtained using monochromatic X-rays. The same setup is used to test the buering capabilities of the modules' readout chip. The maximum rate experienced by the modules produced in Hamburg will be 120 MHz/cm 2 . For this rate the modules' eciency has been measured to be 99%. In view of the module production, the energy calibration procedure has been automated. The modules assigned to the Hamburg production center should be completed by the end of February 2016. For the phase II upgrade, thin silicon sensors with an active thickness of 100 m irradi- ated with protons up to eq = 1 : 3 10 16 cm-2 have been characterized. The charge collection eciency has been measured using pad diodes. Charge multiplication eects have been ob- served for both n- and p-bulk sensors. P-bulk strip sensors with an active thickness of 100 and 200 m have been characterized with a beam test. The signal of these sensors lies be- tween 4000 and 5000 e- after a uence of 1 : 3 10 16 cm-2. The 200 m thick sensors require a higher bias voltage than the 100 m thick sensors to reach this signal height. The threshold necessary to obtain 95% detection eciency is found to be around 2000 e- for the 100 m thick sensors

The thesis includes the study of the signature of heavy quarks and the record of the CERN / Taiwan / Finland module production in CMS barrel pixel detector (BPIX) phase 1 upgrade. For the first part, in order to solve the known problem of a matter-dominant universe, new CP violation source beyond the standard model of particle physics is needed. Adding new heavy quarks, such as sequential 4th generation quarks or vector-like quarks, to the model is a promising candidate solution. When the mass of the new quark is very heavy and hence their associated Yukawa coupling can be very large, a new fireball-like signature may appear if their strong couplings lead to annihilation in a thermal way. The emitted particles from the annihilation could be mainly longitudinal vector bosons, and the multiplicity is exceptionally high. We present the study of such a fireball experimental signature with the fast simulated samples produced by the Madgraph5 generator. The detector effect is modelded by the Delphes package assuming a simplified CMS detector model. If the signal is discovered with a data set corresponding to an integrated luminosity of 100 $fb^{-1}$ collected at the LHC 13 TeV pp collisions, a statistical significance of $5sigma$ can be reached if the mass of the new heavy quark is below 1 TeV/$c^2$. If no excess above the background from other standard model processes is seen, a limit on the new heavy quark mass can be set to 1.35 TeV/$c^2$ at 95\% confidence level. For the second part, the CMS BPIX phase 1 upgrade has been being on going since 2011 with the provision for the progress of the LHC upgrade plans (high-luminosity LHC) and the expectation of even larger instant luminosity ($sim 2 imes 10^{34} cm^{-2}s^{-1}$) and pile-up effect in near future. One of the important tasks is barrel pixel module production which is in charge of five different consortia in Europe. CERN / Taiwan / Finland is the consortium responsible to 176 barrel pixel modules which are one-half the quota required for the Layer-3 BPIX. The module production progressing in CERN, including the module assembly procedure as well as the qualification tests, are recorded. As the writer participated in the x-ray qualification tests, both the procedure and analysis result in x-ray tests would be particularly detailed out. In the end of our module production in August 2016, there are 207 barrel pixel modules contributed to the Layer-3 BPIX, and additional 3 pixel modules to the backup modules for the Layer-4 BPIX.

The identification of b -flavoured jets is key to many physics analyses at the LHC, including measurements involving Higgs bosons or top quarks, and searches for physics beyond the Standard Model. The capacity of ATLAS to efficiently tag b -jets has been enhanced for Run-2 with the addition of the Insertable B Layer (IBL), and improvements in the tracking and b -tagging algorithms. In the algorithm optimisation special emphasis has been placed in improving the performance for reconstructing high-p T b -jets, addressing the challenges posed by track and vertex reconstruction in such an environment. The efficiency and rejection power of these algorithms have been calibrated on data taken in 2015, in particular by exploiting the copious production of b -jets in top quark decays, complemented by studies in multi-jet events.

The ATLAS Experiment is developing the new Inner Tracker (ITk), consisting of a pixel and strip detector, in preparation for the High-Luminosity LHC Upgrade. Essential parts of the ITk Pixel detector are the loaded local supports, which include the silicon pixel modules and associated services. The prototyping has passed its final design review phase in preparation of the construction of the finished detector. The Detector Control System (DCS) is responsible for monitoring and controlling the loaded local supports in the detector. An important part of the DCS is the Monitoring of Pixel System (MOPS), which carries out monitoring of the pixel modules, specifically the voltage drop in their serial powering chains and their temperature. Each serial powering chain of modules is connected to one MOPS chip which is installed on the services of the loaded local supports. The MOPS chips are connected via CAN buses to an FPGA, which sends the monitored data over an OPC UA server to the local DCS control station. The bidirectional interface between the DCS and the MOPS chips is called the MOPS-Hub. In the course of prototyping, the readout of the MOPS chips and the MOPS-Hub was developed and validated. It was successfully operated on the prototype loaded local supports. This contribution will highlight the functionality of the MOPS-Hub and the developed DCS system. Moreover, it will provide insight into the usage of the ITk Pixel MOPS-Hub. This includes its role in the loaded local support readout and detector production, for purposes of both system tests and integration.