The Heavy Flavor Tracker (HFT) is a recently installed micro-vertex detector upgrade to the STAR experiment at RHIC, consisting of three subsystems with various technologies of silicon sensors arranged in 4 concentric cylinders. The two innermost layers of the HFT close to the beam pipe, the Pixel ("PXL") subsystem, employ CMOS Monolithic Active Pixel Sensor (MAPS) technology that integrate the sensor, front-end electronics, and zero-suppression circuitry in one silicon die. This paper presents selected characteristics of the PXL detector part of the HFT and the hardware, firmware and software associated with the readout system for this detector.

A new silicon based vertex detector called the Heavy Flavor Tracker (HFT) was installed at the Soleniodal Tracker At RHIC (STAR) experiment for the Relativistic Heavy Ion Collider (RHIC) 2014 heavy ion run to improve the vertex resolution and extend the measurement capabilities of STAR in the heavy flavor domain. The HFT consists of four concentric cylinders around the STAR interaction point composed of three different silicon detector technologies based on strips, pads and for the first time in an accelerator experiment CMOS monolithic active pixels (MAPS) . The two innermost layers at a radius of 2.8 cm and 8 cm from the beam line are constructed with 400 high resolution MAPS sensors arranged in 10-sensor ladders mounted on 10 thin carbon fiber sectors giving a total silicon area of 0.16 m2. Each sensor consists of a pixel array of nearly 1 million pixels with a pitch of 20.7 μm with column-level discriminators, zero-suppression circuitry and output buffer memory integrated into one silicon die with a sensitive area of ∼ 3.8 cm2. The pixel (PXL) detector has a low power dissipation of 170 mW/cm2, which allows air cooling. This results in a global material budget of 0.5% radiation length per layer for detector used in this run. A novel mechanical approach to detector insertion allows for the installation and integration of the pixel sub detector within a 12 hour period during an on-going STAR run. The detector specifications, experience from the construction and operation, lessons learned and initial measurements of the PXL performance in the 200 GeV Au-Au run will be presented.

A successful OpenPET electronics system needs to provide electronics, especially front-end electronics that are powerful enough to accommodate cutting-edge research. While there are a tremendous number of variations, the relatively simple nature of the data ultimately collected implies that there can be a common set of requirements. In this paper, we describe a 32-channel high-performance Detector Board (DB) designed for OpenPET to meet those requirements. The input stage of the 32-channel DB accepts differential voltages between -2 V and +2 V and has input diodes to protect against over and under voltage. As the input is differential, detector signals of either polarity can be accommodated by selecting which inputs (positive or negative) they are connected to. The input signals are then split and feed to the high-performance energy circuits and the high-performance timing circuits. The outputs of the two circuits are feed to a FPGA for TDC calculation, event data generation and transmission. We have designed, fabricated and tested a 16channel prototype DB. It functions as we expected. The 16channel prototype DB has a similar schematic structure and the same digital parts (ADC, FPGA and etc.) as the 32-channel DB described in this paper. Based on the 16-channel DB, we have completed the schematic design and functional simulation of the 32-channel DB.

Tachyon, a single-ring “demonstration” Time-of-Flight (TOF) PET scanner has been developed to measure the improvement in image quality as a function of the timing resolution. The design of the detector module is optimized for timing by coupling the 6.1×25 mm2 of 6.1×6.1×25 mm3 LSO scintillator crystals onto a 1-inch diameter Hamamatsu R-9800 PMT with super-bialkali photocathode. We characterized the imaging performance of the system. The results show that Tachyon achieved a coincidence timing resolution of 314 ps +/-20 ps fwhm over all crystal-crystal combinations, better than any PET camera that has been reported on. Phantom experiments based on the NEMA NU 2-2007 standard were performed to evaluate the basic imaging performance of the scanner including noise equivalent count rates and image resolution.

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

A silicon-on-insulator (SOI) process for pixelated radiation detectors is developed. It is based on a 0.2 mu M CMOS fully depleted (FD-)SOI technology. The SOI wafer is composed of a thick, high-resistivity substrate for the sensing part and a thin Si layer for CMOS circuits. Two types of pixel detectors, one integration-type and the other counting-type, are developed and tested. We confirmed good sensitivity for light, charged particles and X-rays for these detectors.For further improvement on the performance of the pixel detector, we have introduced a new process technique called buried p-well (BPW) to suppress back gate effect. We are also developing vertical (3D) integration technology to achieve much higher density. (C) 2010 Elsevier B.V. All rights reserved.

A monolithic pixel detector with 0.2μm silicon-on-insulator (SOI) CMOS technology has been developed. It has both a thick high-resistivity sensor layer and thin LSI circuit layer on a single chip. Integration-type and counting-type pixel detectors are fabricated and tested with light and X-rays. The process is open to many researchers through Multi Project Wafer (MPW) runs operated by KEK. Further improvements of the fabrication technologies are also under investigation by using a buried p-well and 3D integration technologies.

We present the design for OpenPET, an electronics readout system designed for prototype radiotracer imaging instruments. The critical requirements are that it has sufficient performance, channel count, channel density, and power consumption to service a complete camera, and yet be simple, flexible, and customizable enough to be used with almost any detector or camera design. An important feature of this system is that each analog input is processed independently. Each input can be configured to accept signals of either polarity as well as either differential or ground referenced signals. Each signal is digitized by a continuously sampled ADC, which is processed by an FPGA to extract pulse height information. A leading edge discriminator creates a timing edge that is "time stamped" by a TDC implemented inside the FPGA. This digital information from each channel is sent to an FPGA that services 16 analog channels, and information from multiple channels is processed by this FPGA to perform logic for crystal lookup, DOI calculation, calibration, etc. As all of this processing is controlled by firmware and software, it can be modified/customized easily. The system is open source, meaning that all technical data (specifications, schematics and board layout files, source code, and instructions) will be publicly available.

The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D0 by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 μs integration time, 400 M pixels and a coverage of -1 < η < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

A system test of various components of the Solenoidal Tracker at RHIC (STAR) detector, operating in concert, has recently come on-line. Communication between a major sub-detector, a Sector of the l i m e Projection Chamber (TPC), and the trigger, data acquisition and slow controls systems has been established, enabling data from cosmic ray muons to be collected. First results from an analysis of the TPC data are presented. These include measurements of system noise, electronic parameters such as amplifier gains and pedestal values, and tracking resolution for cosmic ray muons and laser induced ionization tracks. A discussion on the experience gained in integrating the different components for the system test is also given.

We describe a three Mimostar-2 Monolithic Active Pixel Sensor (MAPS) sensor telescope prototype with an accompanying readout system incorporating on-the-fly data sparsification. The system has been characterized and we report on the measured performance of the sensor telescope and readout system in beam tests conducted both at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) and in the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). This effort is part of the development and prototyping work that will lead to a vertex detector for the STAR experiment.

The ATLAS SemiConductor Tracker (SCT) is a silicon-strip tracking detector which forms part of the ATLAS inner detector. The SCT is designed to track charged particles produced in proton-proton collisions at the Large Hadron Collider (LHC) at CERN at an energy of 14 TeV. The tracker is made up of a central barrel and two identical end-caps. The barrel contains 2112 silicon modules, while each end-cap contains 988 modules. The overall tracking performance depends not only on the intrinsic measurement precision of the modules but also on the characteristics of the whole assembly, in particular, the stability and the total material budget. This paper describes the engineering design and construction of the SCT end-caps, which are required to support mechanically the silicon modules, supply services to them and provide a suitable environment within the inner detector. Critical engineering choices are highlighted and innovative solutions are presented – these will be of interest to other builders of large-scale tracking detectors. The SCT end-caps will be fully connected at the start of 2008. Further commissioning will continue, to be ready for proton-proton collision data in 2008.

The design and technology of the silicon strip detector modules for the Semiconductor Tracker (SCT) of the ATLAS experiment have been finalised in the last several years. Integral to this process has been the measurement and verification of the tracking performance of the different module types in test beams at the CERN SPS and the KEK PS. Tests have been performed to explore the module performance under various operating conditions including detector bias voltage, magnetic field, incidence angle, and state of irradiation up to 3×1014 protons per square centimetre. A particular emphasis has been the understanding of the operational consequences of the binary readout scheme.

The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10Mrad and a 1-MeV neutron equivalent fluence of 2×1014 n/cm2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips assembled into modules meet the rigorous acceptance criteria.

An introduction to the STAR detector and a brief overview of the physics goals of the experiment are presented.

Details concerning the design, fabrication and performance of the STAR Barrel Electromagnetic Calorimeter are presented.

We report the elliptic flow of charged and identified particles at mid-rapidity in Au+Au collisions at √ s NN = 130 GeV using the STAR TPC at RHIC. The integrated elliptic flow signal, v 2 , for charged particles reaches values of about 0.06, indicating a higher degree of thermalization than at lower energies. The differential elliptic flow signal, v 2 (p t) up to 1.5 GeV/c, shows a behavior expected from hydrodynamic model calculations. Above 1.5 GeV/c, the data deviate from the hydro predictions; however the v 2 (p t) is still large, suggesting finite asymmetry for the products of hard scattering. For the identified particles, elliptic flow as a function of p t and centrality differ significantly for particles of different masses. This dependence can be accounted for in hydrodynamic models, indicating that the system created shows a behavior consistent with collective hydrodynamical flow.

A system test of various components of the Solenoidal Tracker at RHIC (STAR) detector, operating in concert, has recently come on-line. Communication between a major sub-detector, a sector of the Time Projection Chamber (TPC), and the trigger, data acquisition and slow controls systems has been established, enabling data from cosmic ray muons to be collected. First results from an analysis of the TPC data are presented. These include measurements of system noise, electronic parameters such as amplifier gains and pedestal values, and tracking resolution for cosmic ray muons and laser induced ionization tracks. A discussion on the experience gained in integrating the different components for the system test is also given.

Highly integrated readout electronics were developed and produced for the 182 000 channels of the four TPCs of the NA49 heavy-ion fixed target experiment at the CERN SPS. The large number of channels, the high packing density and required cost minimization led to the choice of a custom electronics system. The requirements, the design and the performance of the electronics components are described.