MicroTCA implementation of synchronous Ethernet-Based DAQ systems for large scale experiments

Large LAr TPCs are among the most powerful detectors to address open problems in particle and astro-particle physics, such as CP violation in leptonic sector, neutrino properties and their astrophysical implications, proton decay search etc. The scale of such detector implies severe constraints on their readout and DAQ system. In this article we describe a data acquisition scheme for this new generation of large detectors. The main challenge is to propose a scalable and easy to use solution able to manage a large number of channels at the lowest cost. It is interesting to note that these constraints are very similar to those existing in Network Telecommunication Industry. We propose to study how emerging technologies like ATCA and $\mu$TCA could be used in neutrino experiments. We describe the design of an Advanced Mezzanine Board (AMC) including 32 ADC channels. This board receives 32 analogical channels at the front panel and sends the formatted data through the $\mu$TCA backplane using a Gigabit Ethernet link. The gigabit switch of the MCH is used to centralize and to send the data to the event building computer. The core of this card is a FPGA (ARIA-GX from ALTERA) including the whole system except the memories. A hardware accelerator has been implemented using a NIOS II $\mu$P and a Gigabit MAC IP. Obviously, in order to be able to reconstruct the tracks from the events a time synchronisation system is mandatory. We decided to implement the IEEE1588 standard also called Precision Timing Protocol, another emerging and promising technology in Telecommunication Industry. In this article we describe a Gigabit PTP implementation using the recovered clock of the gigabit link. By doing so the drift is directly cancelled and the PTP will be used only to evaluate and to correct the offset.Comment: Talk presented at the 2009 Real Time Conference, Beijing, May '09, submitted to the proceeding

Pulsation du faisceau - Accelerateur 2,5 MV - VdG

CA

High rate, fast timing Glass RPC for the high η\eta CMS muon detectors

The HL-LHC phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. To achieve this goal in a reasonable time scale the instantaneous luminosity would also increase by an order of magnitude up to $6 \cdot 10^{34}$ cm$^{-2}$s$^{-1}$. The region of the forward muon spectrometer ($|\eta| > 1.6$) is not equipped with RPC stations. The increase of the expected particles rate up to 2 kHz/cm$^2$ ( including a safety factor 3 ) motivates the installation of RPC chambers to guarantee redundancy with the CSC chambers already present. The actual RPC technology of CMS cannot sustain the expected background level. A new generation Glass-RPC (GRPC) using low resistivity glass (LR) is proposed to equip at least the two most far away of the four high eta muon stations of CMS. The design of small size prototypes and the studies of their performances under high rate particles flux is presented.Comment: 5 pages, 5 figures, proceeding for the conference VCI 201

Performance of Glass Resistive Plate Chambers for a high granularity semi-digital calorimeter

A new design of highly granular hadronic calorimeter using Glass Resistive Plate Chambers (GRPCs) with embedded electronics has been proposed for the future International Linear Collider (ILC) experiments. It features a 2-bit threshold semi-digital read-out. Several GRPC prototypes with their electronics have been successfully built and tested in pion beams. The design of these detectors is presented along with the test results on efficiency, pad multiplicity, stability and reproducibility.Comment: 16 pages, 15 figure

High rate, fast timing Glass RPC for the high {\eta} CMS muon detectors

The HL-LHC phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. To achieve this goal in a reasonable time scale the instantaneous luminosity would also increase by an order of magnitude up to $6.10^{34} cm^{-2} s^{-1}$ . The region of the forward muon spectrometer ($|{\eta}| > 1.6$) is not equipped with RPC stations. The increase of the expected particles rate up to $2 kHz/cm^{2}$ (including a safety factor 3) motivates the installation of RPC chambers to guarantee redundancy with the CSC chambers already present. The actual RPC technology of CMS cannot sustain the expected background level. The new technology that will be chosen should have a high rate capability and provides a good spatial and timing resolution. A new generation of Glass-RPC (GRPC) using low-resistivity (LR) glass is proposed to equip at least the two most far away of the four high ${\eta}$ muon stations of CMS. First the design of small size prototypes and studies of their performance in high-rate particles flux is presented. Then the proposed designs for large size chambers and their fast-timing electronic readout are examined and preliminary results are provided.Comment: 14 pages, 11 figures, Conference proceeding for the 2016 Resistive Plate Chambers and Related Detector

Construction and commissioning of a technological prototype of a high-granularity semi-digital hadronic calorimeter

A large prototype of 1.3m3 was designed and built as a demonstrator of the semi-digital hadronic calorimeter (SDHCAL) concept proposed for the future ILC experiments. The prototype is a sampling hadronic calorimeter of 48 units. Each unit is built of an active layer made of 1m2 Glass Resistive Plate Chamber(GRPC) detector placed inside a cassette whose walls are made of stainless steel. The cassette contains also the electronics used to read out the GRPC detector. The lateral granularity of the active layer is provided by the electronics pick-up pads of 1cm2 each. The cassettes are inserted into a self-supporting mechanical structure built also of stainless steel plates which, with the cassettes walls, play the role of the absorber. The prototype was designed to be very compact and important efforts were made to minimize the number of services cables to optimize the efficiency of the Particle Flow Algorithm techniques to be used in the future ILC experiments. The different components of the SDHCAL prototype were studied individually and strict criteria were applied for the final selection of these components. Basic calibration procedures were performed after the prototype assembling. The prototype is the first of a series of new-generation detectors equipped with a power-pulsing mode intended to reduce the power consumption of this highly granular detector. A dedicated acquisition system was developed to deal with the output of more than 440000 electronics channels in both trigger and triggerless modes. After its completion in 2011, the prototype was commissioned using cosmic rays and particles beams at CERN.Comment: 49 pages, 41 figure

The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers

The intrinsic time structure of hadronic showers influences the timing capability and the required integration time of hadronic calorimeters in particle physics experiments, and depends on the active medium and on the absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15 small plastic scintillator tiles read out with Silicon Photomultipliers, the time structure of showers is measured on a statistical basis with high spatial and temporal resolution in sampling calorimeters with tungsten and steel absorbers. The results are compared to GEANT4 (version 9.4 patch 03) simulations with different hadronic physics models. These comparisons demonstrate the importance of using high precision treatment of low-energy neutrons for tungsten absorbers, while an overall good agreement between data and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS

Co-simulation domain decomposition algorithm for hybrid EMT-Dynamic Phasor modeling

An iterative coupling algorithm based on restricted additive Schwarz domain decomposition is investigated to co-simulate electrical circuits with hybrid electromagnetic (EMT) and transient stability (TS) modeled using dynamic phasors. This co-simulation algorithm does not introduce any delay between the data exchanged at the co-simulation step. The pure linear convergence property of the iterative method allows it to be accelerated towards the true solution by a non-intrusive Aitken's acceleration of the convergence post-processing, even if the domain decomposition interface conditions make the iterative method divergent. This provides a method less sensitive to the splitting. Numerical tests on a linear RLC circuit combining EMT and TS modeling are provided.Comment: 30 pages, 18 figures, 2 table

Effects of adaptive harvesting on fishing down processes and resilience changes in predator-prey and tritrophic systems

Many world fisheries display a declining mean trophic level of catches. This “fishing down the food web” is often attributed to reduced densities of high-trophic-level species. We show here that the fishing down pattern can actually emerge from the adaptive harvesting of two- and three-species food webs, where changes in fishing patterns are driven by the relative profitabilities of the harvested species. Shifting fishing patterns from a focus on higher trophic levels to a focus on lower trophic levels can yield abrupt changes in the system, strongly impacting species densities. In predator-prey systems, such regime shifts occur when the predator species is highly valuable relative to the prey, and when the top-down control on the prey is strong. Moreover, we find that when the two species are jointly harvested, high adaptation speeds can reduce the resilience of fisheries. Our results therefore suggest that flexibility in harvesting strategies will not necessarily benefit fisheries but may actually harm their sustainability