We present the development of resistive Micromegas with small pad readout aiming at precision tracking without efficiency loss up to several MHz/cm2. Several prototypes have been built with the spark ...protection resistive layer deposited with different techniques: a pad-patterned embedded resistor layout with screen printing, and a uniform layer by sputtering (Diamond Like Carbon structure). All detectors consist of a matrix of 48 × 16 rectangular shaped pads with a pitch of (1 × 3) mm2. The active surface is (48 × 48) mm2 with a total number of 768 channels, routed off-detector for readout. Characterization and performance studies of all prototypes have been carried out by means of radioactive sources, X-rays, cosmic rays and high energy particle beams. A comparison of prototypes with different resistivity layout will be presented.
Jiangmen Underground Neutrino Observatory (JUNO) is a next generation liquid scintillator neutrino experiment under construction phase in South China. Thanks to the anti-neutrinos produced by the ...nearby nuclear power plants, JUNO will be able to study the neutrino mass hierarchy, one of the open key questions in neutrino physics. One key ingredient for a successful measurement is to use high speed, high resolution sampling electronics located very close to the detector signal. Linearity in the response of the electronics is another important ingredient for the success of the experiment. During the initial design phase of the electronics, a custom design with the Front-End and Read-Out electronics located very close to the detector analog signal has been developed and successfully tested. The present paper describes the electronics structure and the first tests performed on the prototypes. The electronics prototypes have been tested and they show good linearity response, with a maximum deviation of 1.3% over the full dynamic range (1-1000 p.e.), fulfilling the JUNO experiment requirements.
This paper describes the design, construction principles and operations of the distillation and stripping pilot plants tested at the Daya Bay Neutrino Laboratory, with the perspective to adapt these ...processes, system cleanliness and leak-tightness standards to the final full scale plants to be used for the purification of the liquid scintillator of the JUNO neutrino detector. The main goal of these plants is to remove radio impurities from the liquid scintillator while increasing its optical attenuation length. Purification of liquid scintillator will be performed with a system combining alumina oxide, distillation, water extraction and steam (or N2 gas) stripping. Such a combined system will aim at obtaining a total attenuation length greater than 20 m @430 nm, and a bulk radiopurity for 238U and 232Th in the 10−15÷ 10−17 g/g range. The pilot plants commissioning and operation have also provided valuable information on the degree of reliability of their main components, which will be particularly useful for the design of the final full scale purification equipment for the JUNO liquid scintillator. This paper describes two of the five pilot plants since the Alumina Column, fluorescent material mixing and the Water Extraction plants are being developed by the Chinese part of the collaboration.
Clock synchronization procedures are mandatory in most physical experiments where event fragments are readout by spatially dislocated sensors and must be glued together to reconstruct key parameters ...(e.g., energy and interaction vertex) of the process under investigation. These distributed data readout topologies rely on an accurate time information available at the front end, where the raw data are acquired and tagged with a precise timestamp prior to data buffering and central data collecting. This makes the network complexity and latency, between front-end and backend electronics, negligible within upper bounds imposed by the front-end data buffer capability where the raw data are stored waiting for the trigger validation. The proposed research work describes a field-programmable gate array (FPGA) implementation of IEEE 1588 Precision Time Protocol (PTP) that exploits the European Organization for Nuclear Research (CERN) timing, trigger, and control (TTC) system as a multicast messaging physical and data link layer. The hardware implementation extends the clock synchronization to the nanoseconds range, overcoming the typical accuracy limitations inferred by computers Ethernet-based local area network (LAN). Establishing a reliable communication between master and timing receiver nodes is essential in a message-based synchronization system. In the backend electronics, the serial data streams synchronization with the global clock domain is guaranteed by a hardware-based finite state machine that scans the bit period using a variable delay chain and finds the optimal sampling point. The validity of the proposed timing system has been proven in point-to-point data links as well as in star topology configurations over standard CAT-5e cables. The results achieved together with weaknesses and possible improvements are hereby detailed.
We present here the strategy and tools developed to time in all the elements of the Level-1 Muon Barrel Trigger of the ATLAS experiment at the CERN Large Hadron Collider. A perfect synchronicity ...among the various trigger elements and with the LHC Bunch Crossing time is vital for the correctness of the ATLAS physics results. We review the possible sources of delays and how they are accounted and corrected for, using a large sample of cosmic ray data collected by ATLAS; and present initial results, that will be refined with early LHC collision data.
Gravimetric methods are expected to play a decisive role in geophysical modeling of the regional crustal structure applied to geoneutrino studies. GIGJ (GOCE Inversion for Geoneutrinos at JUNO) is a ...3‐D numerical model constituted by ~46 × 103 voxels of 50 × 50 × 0.1 km, built by inverting GOCE (Gravity field and steady‐state Ocean Circulation Explorer) gravimetric data over the 6° × 4° area centered at the JUNO (Jiangmen Underground Neutrino Observatory) experiment, currently under construction in the Guangdong Province (China). The a priori modeling is based on the adoption of deep seismic sounding profiles, receiver functions, teleseismic P wave velocity models, and Moho depth maps, according to their own accuracy and spatial resolution. The inversion method allowed for integrating GOCE data with the a priori information and some regularization conditions through a Bayesian approach and a stochastic optimization. GIGJ fits the highly accurate and homogeneously distributed GOCE gravity data with a ~1 mGal standard deviation of the residuals, compatible with the observation accuracy. GIGJ provides a site‐specific subdivision of the crustal layers masses, of which uncertainties include estimation errors, associated to the gravimetric solution, and systematic uncertainties, related to the adoption of a fixed sedimentary layer. A consequence of this local rearrangement of the crustal layer thicknesses is a ~21% reduction and a ~24% increase of the middle and lower crust geoneutrino signal, respectively. The geophysical uncertainties of geoneutrino signals at JUNO produced by unitary uranium and thorium abundances distributed in the upper, middle, and lower crust are reduced by 77%, 55%, and 78%, respectively. The numerical model is available at this site (http://www.fe.infn.it/radioactivity/GIGJ).
Key Points
A gravity‐based 3‐D crustal model beneath the Guangdong province (China) was built to predict the geoneutrino signal at the JUNO experiment
The adopted Bayesian method allows for fitting gravimetric observations integrating local prior distribution with regularization conditions
GIGJ fitted GOCE gravity data with a ~1 mGal standard deviation of the residuals, compatible with the observation accuracy
The 5th International Workshop on Top Quark Physics (TOP 2012) took place in Winchester, UK, from the 16–21 September. It gathered students as well as people active in the top quark sector and ...provided a framework to highlight the newest results and matters related to top quark physics. Discovered in 1995, the top quark is the sixth and heaviest of all quarks, and it is the only one with a lifetime short enough to be observed 'naked'. This makes it an important testing ground in the search for new physics. In fact, the fact of its mass being so much larger than the other quarks, hints at its special role in the Higgs mechanism. For the same reason, in many models of New Physics, new heavy resonances are expected to couple mostly with top quarks. Even if no new particles are observed, the direct correlation between its angular momentum and that of its detectable decay products allows us to probe indirectly New Physics in action when top quarks are created. In this edition of the TOP conference series, for the first time, the agenda was equally balanced between 'traditional' measurements and the now vast number of searches for physics BSM in the top quark sector, thanks mostly to the amount of data collected at the LHC in its Run I. New results were presented by both the Tevatron and the LHC collaborations: improved ttbar and single top cross-section measurements, refined techniques to measure the top quark mass and a large number of results on properties such as spin correlation and W boson polarization in top quark decays were shown. More technical discussions on the experimental issues, both from the detector and the simulation side also took place, drawing together experimentalists and theorists. Reviews of the latest results on ttbar asymmetry both from CDF and D0 and from ATLAS and CMS were shown, and theorists active in the field made some interesting points on this hot topic. Additionally, results on the search for fourth generation fermions and new resonances in the boosted top regime were also provided. Finally, a set of dedicated talks on the interplay between the top sector and other hot subjects, like the Higgs and SUSY, were given both at the theory and experimental level. Furthermore, ad hoc student sessions were organized to allow younger colleagues to pose questions to the senior experts in the field and contribute with their more recent studies. The conference has been a definitive success, not just scientifically: about 130 participants from all over the world created a collegiate spirit which culminated in the social events at Winchester Hall below King Arthur's table; and in a cosy 16th century barn for the social dinner. The Local Organizing Committee would like to thank all participants, and in particular the speakers, for their high level contributions to TOP 2012 and for making this a very fruitful and pleasant time together. We conclude by wishing the Organizing Committee of TOP 2013 all the best for a successful conference. We look forward to seeing everyone in Germany in 2013. Giuseppe Salamanna Local Organizing Committee London, June 2013 Local Organising Committee Veronique Boisvert (Chair, Royal Holloway, University of London) Lucio Cerrito (Queen Mary, University of London) Akram Khan (Brunel University, London) Stefano Moretti (University of Southampton) Mark Owen (University of Manchester) Giuseppe Salamanna (Queen Mary, University of London) Christian Schwanenberger (University of Manchester) International Advisory Committee Roberto Tenchini (INFN, Pisa) Martine Bosman (IFAE, Barcelona) Michelangelo Mangano (CERN) Scott Willenbrock (University of Illinois, Urbana) Werner Bernreuther (RWTH, Aachen) Jorgen D'Hondt (VUB, Brussels) Antonio Onofre (LIP, University Minho) Fabio Maltoni (UCL, Louvain) Eric Laenen (NIKHEF) Fabrizio Margaroli (INFN, Roma 1) Juan Antonio Aguilar Saavedra (University of Granada) Yvonne Peters (University of Manchester) Roberto Chierici (CERN) Markus Cristinziani (University of Bonn)
In this paper we provide a detailed technical description of the Front-End (FE) electronics for the liquid Argon instrumentation of the LEGEND-200 experiment, searching for the very rare, ...hypothetical neutrinoless double \(\beta\) decay process at the Italian Laboratori Nazionali del Gran Sasso. The design stems from the need to read out the silicon photo-multiplier response to the scintillation light in the liquid Argon with excellent single-photon resolution. The FE electronics is required to be placed far from the detectors to meet the experiment's radio-purity constraints. This constraint represents a challenge for a high signal-to-noise ratio. We address how this could be achieved in a stable way. The system was installed in July 2021 and has been commissioned with the rest of LEGEND-200, proving we could attain a very low overall level of electrical noise of 250 \(\mu\)V peak-to-peak.
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