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Time-of-flight (TOF) and coincident scattering measurements were conducted to measure the light response of a pressurized ^4He fast neutron scintillation detector as a function of deposited energy up to 5 MeV. The energy deposited in the detector by a neutron was measured by its angle of scatter and compared to the resulting light output. Whereas previous research has exclusively focussed on the energy information contained in the slow component, this work demonstrates that the fast component is also sensitive to neutron energy, and the entire scintillation signal can therefore be used. The gamma rejection capability of the detector was also measured for a variety of gamma sources. The detector demonstrated a inherent gamma rejection rate of 97.31%, which was increased to 99.89% after the application of pulse shape discrimination (PSD) algorithms. The characterization of gamma rejection and light response parameters will enable implementation of these detectors for neutron spectroscopy in mixed radiation fields. [ABSTRACT FROM PUBLISHER]

In modern positron emission tomography (PET) readout architectures, the position and energy estimation of scintillation events (singles) and the detection of coincident events (coincidences) are typically carried out on highly integrated, programmable printed circuit boards. The implementation of advanced singles and coincidence processing (SCP) algorithms for these architectures is often limited by the strict constraints of hardware-based data processing. In this paper, we present a software-based data acquisition and processing architecture (DAPA) that offers a high degree of flexibility for advanced SCP algorithms through relaxed real-time constraints and an easily extendible data processing framework. The DAPA is designed to acquire detector raw data from independent (but synchronized) detector modules and process the data for singles and coincidences in real-time using a center-of-gravity (COG)-based, a least-squares (LS)-based, or a maximum-likelihood (ML)-based crystal position and energy estimation approach (CPEEA). To test the DAPA, we adapted it to a preclinical PET detector that outputs detector raw data from 60 independent digital silicon photomultiplier (dSiPM)-based detector stacks and evaluated it with a [^18F]-fluorodeoxyglucose-filled hot-rod phantom. The DAPA is highly reliable with less than 0.1% of all detector raw data lost or corrupted. For high validation thresholds (37.1 $\pm$ 12.8 photons per pixel) of the dSiPM detector tiles, the DAPA is real time capable up to 55 MBq for the COG-based CPEEA, up to 31 MBq for the LS-based CPEEA, and up to 28 MBq for the ML-based CPEEA. Compared to the COG-based CPEEA, the rods in the image reconstruction of the hot-rod phantom are only slightly better separable and less blurred for the LS- and ML-based CPEEA. While the coincidence time resolution ($\sim$ 550 ps) and energy resolution ($\sim$12.3%) are comparable for all three CPEEA, the system sensitivity is up to 2.5$\times$ higher for the LS- and ML-based CPEEA. [ABSTRACT FROM AUTHOR]

In the frame of the French trans-governmental R&D program against CBRN-E threats, CEA (French Alternative Energies and Atomic Energy Commission) is studying the detection of Special Nuclear Materials (SNM) by neutron interrogation with the Associated Particle Technique (APT). Coincidences including at least 3 fission neutrons or gamma rays induced by tagged neutrons are used to detect and distinguish SNM from benign materials in which lower multiplicity events of 1 or 2 particles are produced by (n,2n) or (n,n’\gamma) reactions. Coincidences are detected by fast plastic scintillators and correlated with tagged neutrons to improve the signal-to-noise ratio. Dedicated data acquisition electronics (DAQ) have been developed with independent FPGA cards associated with each detector, so that the acquisition window can be opened by any of the plastic scintillators. DAQ tests in passive mode are presented, in which acquisition is triggered by the sum signal of all detectors. The system time and energy calibration and resolution are reported, as well as the qualification of numerical simulations thanks to experimental data acquired with simple setups using a ^252Cf source. Numerical studies for the design and performance of cargo container inspection are also performed with the MCNP-PoliMi computer code and the ROOT data analysis package. SNM detection in iron matrix is quite straightforward, but in organic matrix, data processing will need to combine more information to evidence SNM. [ABSTRACT FROM PUBLISHER]

A DAQ architecture for a PET system is presented that focuses on modularity, scalability and reusability. The system defines two basic building blocks: data acquisitors and concentrators, which can be replicated in order to build a complete DAQ of variable size. Acquisition modules contain a scintillating crystal and either a position-sensitive photomultiplier (PSPMT) or an array of silicon photomultipliers (SiPM). The detector signals are processed by AMIC, an integrated analog front-end that generates programmable analog outputs which contain the first few statistical moments of the light distribution in the scintillator. These signals are digitized at 156.25 Msamples/s with free-running ADCs and sent to an FPGA which detects single gamma events, extracts position and time information online using digital algorithms, and submits these data to a concentrator module. Concentrator modules collect single events from acquisition modules and perform coincidence detection and data aggregation. A synchronization scheme over data links is implemented that calibrates each link’s latency independently, ensuring that there are no limitations on module mobility, and that the architecture is arbitrarily scalable. Prototype boards with both acquisition and concentration functionality have been built for evaluation purposes. The performance of a small PET system with two detectors based on continuous scintillators is presented. A synchronization error below 50 ps rms is measured, and energy resolutions of 19% and 24% and timing resolutions of 2.0 ns and 4.7 ns FWHM are obtained for PMT and SiPM photodetectors, respectively. [ABSTRACT FROM PUBLISHER]

Abstract: The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented. [ABSTRACT FROM AUTHOR]

Abstract: An upgrade electronics design for Plastic Ball detector is described. The Plastic Ball detector was a part of several experiments in the past and its back portion (proposed to be used in Main Injector Particle Production (MIPP)) consists of 340 photomultipliers equipped with a sandwich scintillator. The scintillator sandwich has fast and slow signal component with decay times 10ns and 1μs, respectively. The upgraded MIPP experiment will collect up to 12,000 events during each 4s spill and read them out in ∼50s between spills. The MIPP data acquisition system will employ deadtime-less concept successfully implemented in Muon Electronics of Dzero experiment at Fermilab An 8-channel prototype design of the Plastic Ball Front-End (PBFE) implementing these requirements is discussed. Details of the schematic design, simulation and prototype test results are discussed. [Copyright &y& Elsevier]

We have developed a new X-ray cone-beam tomograph for in vivo small-animal imaging using a flat panel detector (CMOS technology with a microcolumnar CsI scintillator plate) and a microfocus X-ray source. The geometrical configuration was designed to achieve a spatial resolution of about 12 lpmm with a field of view appropriate for laboratory rodents. In order to achieve high performance with regard to per-animal screening time and cost, the acquisition software takes advantage of the highest frame rate of the detector and performs on-the-fly corrections on the detector raw data. These corrections include geometrical misalignments, sensor non-uniformities, and defective elements. The resulting image is then converted to attenuation values. We measured detector modulation transfer function (MTF), detector stability, system resolution, quality of the reconstructed tomographic images and radiated dose. The system resolution was measured following the standard test method ASTM E 1695 -95. For image quality evaluation, we assessed signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) as a function of the radiated dose. Dose studies for different imaging protocols were performed by introducing TLD dosimeters in representative organs of euthanized laboratory rats. Noise figure, measured as standard deviation, was 50 HU for a dose of 10 cGy. Effective dose with standard research protocols is below 200 mGy, confirming that the system is appropriate for in vivo imaging. Maximum spatial resolution achieved was better than 50 micron. Our experimental results obtained with image quality phantoms as well as with in-vivo studies show that the proposed configuration based on a CMOS flat panel detector and a small micro-focus X-ray tube leads to a compact design that provides good image quality and low radiated dose, and it could be used as an add-on for existing PET or SPECT scanners. [ABSTRACT FROM PUBLISHER]

A data acquisition system for a positron emission tomograph (PET) based on avalanche photodiode (APD) readout of lutetium oxyorthosilicate (LSO) scintillator crystals is presented. The analog data of each APD are read out by fast analog to digital converters (ADCs) and processed within field programmable gate arrays (FPGAs). The ADCs are continuously sampling with a 80 MHz, low jitter clock, which is synchronous for the whole detector. The main tasks of the FPGAs are pulse detection and extraction of signal timing information from the digitized data stream. The detected signal pulse data are therefore compared to a predefined set of pulse shapes with known phase shifts with respect to the sample clock. By searching for the best match within this calibration set, a precise start time information for the signal pulse can be determined. The calculated time values are then transmitted from the ADC cards via fiber optic links to multiplexer modules which combine the different data streams and can also perform further processing like search for coincident events. Finally, the preprocessed detector data are transmitted from the multiplexers to PCI cards in the image reconstruction computers by gigabit optical links. [ABSTRACT FROM AUTHOR]

An overview of the Dø Central Track Trigger (CTT) for the Tevatron Run 2 program is presented. This newly commissioned system uses information from the Dø Central Fiber Tracker and Preshower Detectors to generate trigger information for the first level of the three-tiered Dø Trigger. The system delivers tracking detector trigger decisions every 132 ns, based on input data flowing at a rate of 475 Gbit per second. Initial results indicate excellent performance of the CTT. First studies of efficiency and trigger performance of the CTT are presented. [ABSTRACT FROM AUTHOR]