The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

The ATLAS ITk Strip Detector System for the Phase-II LHC Upgrade

The High Luminosity Large Hadron Collider (HL-LHC) is expected to provide an integrated luminosity of 4000 fb-1, that will allow to perform precise measurements in the Higgs sector and improve searches of new physics at the TeV scale.The HL-LHC higher particle fluences and will requested radiation hardness, the increased average proton-proton pile-up interactions, require a significant scaling of the existing Inner Detector.ATLAS is currently preparing for the HL-LHC upgrade, and an all-silicon Inner Tracker (ITk) will replace the current Inner Detector, with a pixel detector surrounded by a strip detector. The strip system consists of 4 barrel layers and 6 EC disks. After completion of final design reviews in key areas, such as Sensors, Modules, Front-End electronics and ASICs, a large scale prototyping program has been completed in all areas successfully. We present an overview of the Strip System, and highlight the final design choices of sensors, module designs and ASICs. We will summarise results achieved during prototyping and the current status of pre-production on various detector components, with an emphasis on QA and QC procedures and the preparation for the production phase distributed over many institutes, which is foreseen to start in a few months

The ATLAS ITk Strip Detector System forthe Phase-II LHC Upgrade

The High Luminosity Large Hadron Collider (HL-LHC) is expected to provide an integrated luminosity of 4000 fb-1, that will allow to perform precise measurements in the Higgs sector and improve searches of new physics at the TeV scale.The HL-LHC higher particle fluences and will requested radiation hardness, the increased average proton-proton pile-up interactions, require a significant scaling of the existing Inner Detector.ATLAS is currently preparing for the HL-LHC upgrade, and an all-silicon Inner Tracker (ITk) will replace the current Inner Detector, with a pixel detector surrounded by a strip detector. The strip system consists of 4 barrel layers and 6 EC disks. After completion of final design reviews in key areas, such as Sensors, Modules, Front-End electronics and ASICs, a large scale prototyping program has been completed in all areas successfully. We present an overview of the Strip System, and highlight the final design choices of sensors, module designs and ASICs. We will summarise results achieved during prototyping and the current status of pre-production on various detector components, with an emphasis on QA and QC procedures and the preparation for the production phase distributed over many institutes, which is foreseen to start in a few months

Thermo-mechanical petals

Mechanical description of the Thermo-mechanical Petal prototype incl. an overview of Modules, electronic components and the first results of the thermal simulation

Performance study of dual-phase CO2{}_2 cooling on the example of the ATLAS ITk strip end-cap detector

The technique of evaporative CO${}_2$ cooling is one of the standard cooling options for high-energy particle detectors, such as the new ATLAS Inner Tracker (ITk) for the planned high-luminosity upgrade of the LHC by 2026. The advantages of CO${}_2$ are a high latent heat transfer at reasonable flow parameters, a low viscosity which allows to use small diameter cooling pipes with a low pressure drops, a well-suited temperature range for detector cooling between ＋25 and −40 °C and being an environment friendly alternative to many other currently used coolants. When comparing with a monophase coolant, the operation in the dual-phase regime comes with several parameters influencing the cooling performance.This paper contains the results of experimental studies performed to understand these influencing factors. For this, prototype structures from the ITk strip detector end-cap were used, like bare local support structures (‘cores’) or fully loaded structures (‘petals’). Here, the design is optimized to guarantee a good heat transfer between the silicon strip modules glued on the surface and the embedded titanium cooling pipe with the CO${}_2$ coolant. Systematic investigations on the thermal performance using infrared thermography are used to study the influence of dual-phase CO${}_2$ cooling parameters such as the orientation of CO${}_2$ flow. Moreover, the dependence of the pressure drop as a key parameter for the cooling performance on the applied heat load or the selected mass flow rate is investigated

Petalet prototype for the ATLAS silicon strip detector upgrade

To achieve more precise measurements and to search new physics phenomena, the luminosity at the LHC is expected to be increased during a series of upgrades in the next years. The latest scheduled upgrade, called the High Luminosity LHC (HL-LHC) is proposed to provide instantaneous luminosity of 5×1034cm2s−1. The increased luminosity and the radiation damage will affect the current Inner Tracker. In order to cope with the higher radiation dose and occupancy, the ATLAS experiment plans to replace the current Inner Detector with a new all-silicon tracker consisting of ∼8 m2 pixel and ∼192 m2 strip detectors. In response to the needs, highly modular structures will be used for the strip system, called Staves for the barrel region and Petals for the end-caps region. A small-scaled prototype for the Petal, the Petalet, is built to study some specialties of this complex wedge-shaped structures. The Petalet consists of one large and two small sized sensors. This report will focus on the recent progress in the prototyping of the Petalet and their electrical performances

Recent results from the first lpGBT-based prototype of the End-of-Substructure card for the ATLAS Strip Tracker Upgrade

The building blocks of the upgraded ATLAS Strip Tracker for HL-LHC are modules that host silicon sensors and front-end ASICs. The modules are mounted on carbon-fibre substructures hosting up to 14 modules per side. An End-of-Substructure (EoS) card on each substructure connects up to 28 differential data lines at 640 Mbit/s to lpGBT and VL+ ASICs that provide data serialisation and 10 GBit/s optical data transmission to the off-detector systems respectively. Prototype EoS cards have been designed and extensively tested using lpGBT and VL+ prototypes. The status of the electronics design and recent test results are presented

HSA binding of HIV protease inhibitors: a high performance affinity chromatography study

The binding of HIV protease inhibitors, drugs important for anti-HIV chemotherapy, to human serum albumin (HSA) was examined by high-performance affinity chromatography. Frontal analysis was first used to determine the amount of anchored protein and the binding capacity for selected markers on this column. Zonal elution experiments then ranked the HSA bound fraction of the examined compounds. Information on the binding region was obtained by competitive zonal elution experiments using probe compounds with known sites on HSA. An allosteric competition between HIV protease inhibitors (PIs) and valproate (a probe for the bilirubin site) was detected, consistent with a non-cooperative binding mechanism. No significant competition was observed between the examined compounds and salicylate or ibuprofen, probes for sites I and II, respectively. The observations were confirmed by circular dichroism spectroscopy, based on the change in the induced circular dichroism signals of selected markers for the main binding sites of HSA when ritonavir was added as the competitor. These results were in good agreement with previous literature reports and provide more details on how PIs are transported in plasma and how they may compete with other drugs in the body

Performance tests of dual-phase CO2{}_2 cooling for particle detectors

Evaporative CO${}_2$ cooling is becoming a popular cooling solution for large-scale, high-energy particle detectors, such as the new ATLAS Inner Tracker (ITk) for the high-luminosity upgrade of the LHC. CO${}_2$ offers a high latent heat transfer at reasonable flow parameters and is an environment friendly alternative to many other coolants currently used. This cooling technique is used to investigate the thermal performance of prototypes from the ITk strip detector produced at DESY. The strip end-cap local support structure, called petal core, is designed to allow a good heat transfer between silicon strip modules glued on its surface and the embedded titanium cooling pipe. Studies on the thermal properties using infrared thermography have been performed to analyse the heat dissipation path which allows also to detect eventual imperfections in the assembly as part of the quality control strategy. A similaranalysis was executed on a petal loaded with electrical modules to study the heat generation due to active components and its dissipation for each module under different CO${}_2$ conditions