Over the last two decades, the possibility of using RPCs in outdoors systems has increased considerably. Our group has participated in this effort by installing several systems and continues to work on their optimization, while simultaneously studying and developing new approaches that can use RPCs in outdoor applications.In particular, four detectors were deployed in the field at the Pierre Auger Observatory in 2019 remained inactive, awaiting the commissioning of support systems. During the pandemic the detectors were left without gas flow for more than two years, but were recently reactivated with no major problems.The LouMu project combines particle physics and geophysics in order to map meter-scale geologic structures, using Muon Tomography. Transmission muography is sensitive to the total amount of matter crossed by the muons, allowing to separate targets of different densities. In this exploratory project, it serves to identify unconsolidated rock zones, like geological faults and ore masses around an old Pyrite mine, now converted into a science center. The general goal is to compare how effective is the muographic survey when compared with the more standard geophysical techniques. The development of the RPC system used and the data from the last two years will be presented.Finally, recent advances in a large area (1 m2) double gap-sealed RPC will be presented.

The TRASGO project develops high resolution tracking detectors, sensitive to single electrons and muons as well as to bundles of both kinds of particles. Two detectors are now operative and two more stations will start taking data for atmospheric studies soon. Thanks to the identification capability of the detectors, they are well suited to estimate the arrival rates of primary cosmic rays with different energy thresholds. This is validated after performing several simulations and opens new possibilities in the research of cosmic rays from ground-based detectors.

The Carpet-3 experiment for investigation of gamma-radiation with energy above 100 TeV is currently being prepared at the Baksan Neutrino Observatory of the Institute for Nuclear Research, RussianAcademy of Sciences. At present the plastic scintillation counters with a total continuous area of 410 m2 are installed in the muon detector (MD) underground tunnel, and they are totally equipped with electronics. The counters’ gains and thresholds have been adjusted. Fifteen modules of shower detectors are placed on the surface of the MD absorber. Ten of them contain 9 standard plastic counters with an area of 1 m2 each. Also 24 modules without counters are arranged on the territory of the array. These modules will accomplish a surface part of the Carpet-3 array. The preliminary estimates show that the new array will have the best sensitivity to the flux of primary gamma rays with energy

SHiP (Search for Hidden Particles) is a general-purpose experiment to be installed in a new beam-dump facility at the SPS at CERN to search for hidden particles as predicted by a very large number of recently elaborated models. The proposed experimental apparatus contains, among others, a 50 m2 Timing Detector, crucial to reject the combinatorial background, with a requirement of a timing precision better than 100 ps together with the highest possible detection efficiency. One possibility for the construction of the Timing Detector is the Multigap Resistive Plate Chamber (MRPC) technology. In this paper, we report the design and test beam results of the first full-scale module, based on a novel concept on the construction of MRPCs, where the glass stack and high-voltage electrodes are confined within a permanently sealed plastic box, exhibiting a time precision of 54 ps together with a detection efficiency of 98% over almost 2 m2 of active area.

We report on an architecture of a multi-purpose trigger system based on inexpensive and off-the-shelf modules, with logic implemented in three levels, that can be used in a variety of small/medium systems just by writing a few registers using the accompanying software. The developed trigger algorithms are described in Very High Speed Integrated Circuits (VHSIC) Hardware Description Language (VHDL) and implemented using a Xilinx XC6LX45-2 FPGA. In its present implementation, for the sake of simplicity, communication with the external world is done using the Serial Peripheral Interface (SPI), which allows easy connection to a Raspberry Pi2 running Linux. The Raspberry software was written in C++ and enables configuring and checking of the underlying FPGA and retrieving the monitoring data. The system has been used, with success, in several applications, from lab setup to industrial and pre-clinical environments showing its versatility and robustness.

The TOF-tracker concept, the simultaneous measurement of accurate time and bi-dimensional space coordinates in a single gaseous detector, has been previously demonstrated based on Resistive Plate Chamber (RPC) technology. Recently, a larger area, 1550 × 1250 mm2, RPC detector has been built. Signals are induced on metallic strips located in each side of the RPC active volume and coupled to both charge-sensitive and timing circuits, that can be used to generate a coincidence trigger. In this work, the architecture and performance of the trigger system of the detector is reported. The system is based on off-the-shelf inexpensive modules and in a custom program written in VHDL running in a Xilinx Spartan-6 FPGA. It is fast, fully parameterized and supports several trigger strategies, allowing at the same time the collection of data referring to the operating condition of the detector, relevant for tests and detector maintenance.

Optical Coherence Tomography (OCT) is a high-resolution, non-invasive and contactless imaging technique based on optical interferometry. After the Time Domain (TD) and the Spatially Encoded Frequency Domain (SEFD), the Swept-Source (SS) OCT, also known as Time Encoded Frequency Domain (TEFD) OCT, is the latest technology available. It is based on a fast wavelength-sweeping of a narrow laser line over the bandwidth of the source. SWEEP TRIGGER and K-CLOCK signals are provided by the laser source and establish the time base for the overall system. Data acquisition and the two-dimensional scanning of the object of interest must be accurately synchronized after those signals. The proposed solution for the overall scanning/acquisition/sweeping synchronism is an integrated and dedicated FPGA-based control system that is being developed and will generate the automatic, programmable and flexible operation that will replace the present, manually adjustable, system. This way, complete reproducibility of experimental conditions will be obtained, along with the possibility of optimizing the galvanometer /mirrors control. This system is being built around a Xilinx XC6SLX45 FPGA and will be integrated in the already developed control software of the OCT system.

The TOF-tracker concept, the simultaneous measurement of accurate time and bi-dimensional space coordinates in a single gaseous detector, has been previously demonstrated. Recently, a larger area, 1550×1250 mm2, RPC detector has been constructed. Signals are induced in metallic strips located in each side of the RPC active volume and coupled to both charge-sensitive and timing circuits, that can be used to generate a coincidence trigger. In this work, the architecture and performance of the trigger system of the detector is reported. The system is based on off-the-shelf inexpensive modules and in a custom program written in VHDL running in a Xilinx Spartan-6 FPGA. It is fast, fully parameterized and supports several trigger strategies, allowing at the same time the collection of several information referring to the operating condition of the detector, relevant for tests and detector maintenance.

The TOF-tracker concept, the simultaneous measurement of accurate time and bi-dimensional space coordinates in a single gaseous detector, has been previously demonstrated. The detector yielded a time resolution of 77 ps sigma along with a bi-dimensional position resolution of 38 mu m sigma over a full active area of 60 x 60 mm(2). In here, we report about a large area, 1550 x 1250 mm(2), TOF-tracker device, tested by tracking cosmic muons, yielding a position resolution down to 1.33 mm sigma, a simultaneous time resolution of 150 ps sigma and 92% detection efficiency, over the entire area of the detector. The sub-millimetre electronic resolution of the readout chain suggests that the position resolution here reported could be dominated by non-corrected systematic effects and therefore it could be yet significantly improved.

Current work aiming at studying the feasibility of a resistive plate chamber (RPC)PET camera for human whole-body screening indicates that a very cost-effective and high-sensitivity camera can be built. Such a camera will use the high intrinsic time resolution (better than 300 ps full width at half maximum (FWHM) of the RPC technology to implement a time of flight (TOF)-PET camera that, along with its very large field of view, can reach a sensitivity exceeding the present crystal-based PET technology by a factor up to 20 with a spatial resolution near 2 mm.Due to the large number of RPC plates forming such a system (in the order of 100 RPC plates, or even more) and to the large amount of data generated it is essential to have an effective on-line trigger that helps reducing the pressure on the data saving and processing system.In this work we present simulation results of an all-digital coincidence-detection system implemented in a Field Programmable Gate Array (FPGA) that can cope with the task of generating the high speed trigger for such a camera. The method implemented for coincidence detection is virtually dead-time free and very fast. It is shown the trigger system can process all the events inside the RPC-PET camera in real-time. This will allow a better understanding of the camera and will contribute to its optimization, simplifying significantly the design of its data acquisition system.

A complex task for positron emission tomography (PET) cameras is the design of an appropriate coincidence-detection trigger system as it usually encompasses coincidences in a large number of channels and requires tight time specifications. Those requirements are even greater for a resistive plate chamber (RPC)-based detector technology since the time window specification is quite small (in the order of a few hundred picoseconds) and the number of coincidence-channels can be quite large. Previous work showed that the time resolution for gamma photon pairs of a detector based on resistive plate chamber technology is under 300 ps full width at half maximum. This allows for a very tight time window for coincidence detection, with the corresponding benefits in reducing the number of random coincidences observed and, hence, the overall noise on the acquired image. In this paper, we first show experimental results of a coincidence-detection algorithm implemented inside a Xilinx Virtex-5 field-programmable gate array for a small-animal RPC-PET camera being built.

The time resolution for gamma photon pairs of a detector based on resistive plate chamber technology is close to 300 ps FWHM. This allows a tight time window for coincidence detection, reducing the number of random coincidences observed and the overall noise of the acquired image. We implemented, inside a Xilinx Virtex-5 field programmable gate array, a fully programmable coincidence-trigger system with sub-nanosecond resolution and low latency for a small animal RPC-PET camera being built. An automatic procedure to construct a histogram of coincidences was implemented that helps characterizing the camera and allows compensating for different delays in the time channels. The time window for coincidences can then be placed at the optimal position helping to reject coincidences from undesired sources.

A complex task for PET cameras is the design of an appropriate coincidence-detection trigger as it usually encompasses coincidences in a large number of channels and tight time specifications. Those requirements are even greater for a resistive plate chamber (RPC)-based detector technology as the time window specification is quite small (in the order of a few hundred picoseconds) and the number of coincidence-channels can be quite large (more than 100 in a large camera). In this work we discuss on-going work aimed at implementing the coincidence-detection algorithm inside a FPGA along with the necessary TDCs. The use of the developed solution in a first prototype of an RPC-based small animal PET and its scalability to the case of a human, all-body, PET, is discussed.

A general data acquisition architecture, allowing a clean conceptual separation of the fundamental blocks in a data acquisition setup, is presented. The approach taken surfaced from a study of several modern architectures and from experience acquired while developing an object-oriented programming solution for a previously developed high-speed architecture. This process of software development leaded naturally to a concept where a net separation between data transfer, and control and trigger signals, suggested a similar general decomposition of the data acquisition hardware, in such a way that the same fundamental hardware blocks can be used in several different configurations.In this paper we report on the strategy and results obtained while developing in VHDL such an important and fundamental unit of the data acquisition chain as the data acquisition saving block. The solution proposed for the data saving block, tested using field programmable gate arrays, implements pre- and post-trigger functionality, supports continuous data streams up to hundreds of MHz, has a large memory pool (hundreds of megabytes), and has an interface capable of providing, upon request, a block of data from a specified address without interfering with the data saving process.

Interleaving data acquisition channels is a well-known and interesting technique to achieve higher acquisition rates. However, to obtain the expected benefits, a careful look at the interleaving technique and to mismatches that can lead to unwanted harmonic distortion and noise is essential.In this paper we discuss the methods used to interleave existing high-speed, 250 MSPS 8-bit acquisition channels, and the results obtained. The methods presented allowed a good relative channel calibration in amplitude (amplitude mismatch under 0.1 lsb) and in time (time mismatch between acquisition channels in the ps range, under the specified maximum jitter for the ADC used).A dynamic, by software, amplitude level signal-dependent adjustment procedure is also suggested for signals with rich frequency content that can substantially improve the quality of the acquired signal when using interleaved channels.The techniques presented provide good results even in the presence of noise.