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Radiation Tolerant Electronics and Digital Processing for the Phase-I Trigger Readout Upgrade of the ATLAS Liquid Argon Calorimeters

The high luminosities of L > 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC) at CERN produce an intense radiation environment that the detectors and their electronics must withstand. The ATLAS detector is a multi-purpose apparatus constructed to explore the new particle physics regime opened by the LHC. Of the many decay particles observed by the ATLAS detector, the energy of the created electrons and photons is measured by a sampling calorimeter technique that uses Liquid Argon (LAr) as its active medium. The front end (FE) electronic readout of the ATLAS LAr calorimeter located on the detector itself consists of a combined analog and digital processing system. In order to exploit the higher luminosity while keeping the same trigger bandwidth of 100 kHz, higher transverse granularity, higher resolution and longitudinal shower shape information will be provided from the LAr calorimeter to the Level-l trigger processors. New trigger readout electronics have been designed for this purpose, which will withstand the radiation dose levels expected for an integrated luminosity of 3000 fb{sup -1} during the high luminosity LHC (HL-LHC), which is well above the original LHC design qualifications. (authors)

43 PARTICLE ACCELERATORS↗

Updates on the Progress of the Alternate Topology Modulator (AT-HVCM) to support the Proton Power Upgrade (PPU) at the Spallation Neutron Source

The AT-HVCM, achieved by series-stacking the dual-function resonant filter capacitors following each rectification stage, is the baseline design for the PPU project at the SNS [1]. The project requires three AT-HVCM modulators to power 28 additional 700kW klystrons and associated high beta cavities to accelerate 38mA of beam current to 1.3GeV. Each modulator produces an 82 kV, 120A output pulse of 1.35ms duration at a 60Hz repetition rate. The AT design approach improves upon the existing HVCM topology, reducing stresses on the H bridge IGBTs using zero voltage (ZVS) and current switching (ZCS) techniques and on the resonant filter capacitors by limiting voltage reversal. This paper reviews the prototype development progress, currently focused on evaluating system reliability, and discusses some design techniques to achieve the modulator performance requirements.

Solley, Dennis J.↗

Upgrade of the Minos+ Experiment Data Acquisition for the High Energy NuMI Beam Run

The Minos+ experiment is an extension of the Minos experiment at a higher energy and more intense neutrino beam, with the data collection having begun in the fall of 2013. The neutrino beam is provided by the Neutrinos from the Main Injector (NuMI) beam-line at Fermi National Accelerator Laboratory (Fermilab). The detector apparatus consists of two main detectors, one underground at Fermilab and the other in Soudan, Minnesota with the purpose of studying neutrino oscillations at a base line of 735 km. The original data acquisition system has been running for several years collecting data from NuMI, but with the extended run from 2013, parts of the system needed to be replaced due to obsolescence, reliability problems, and data throughput limitations. Specifically, we have replaced the front-end readout controllers, event builder, and data acquisition computing and trigger processing farms with modern, modular and reliable devices with few single points of failure. The new system is based on gigabit Ethernet TCP/IP communication to implement the event building and concatenation of data from many front-end VME readout crates. The simplicity and partitionability of the new system greatly eases the debugging and diagnosing process. As a result, the new system improves throughput by about a factor of three compared to the old system, up to 800 megabits per second, and has proven robust and reliable in the current run.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗