Measurement of the π− -Ar total hadronic cross section at the LArIAT experiment

We present the first measurement of the negative pion total hadronic cross section on argon in a restricted phase space, which we performed at the Liquid Argon In ATestbeam (LArIAT) experiment. All hadronic reaction channels, as well as hadronic elastic interactions with scattering angle greater than 5° are included. The pions have kinetic energies in the range 100–700 MeVand are produced by a beam of charged particles impinging on a solid target at the Fermilab test beam facility. LArIAT employs a 0.24 ton active mass liquid argon time projection chamber (LArTPC) to measure the pion hadronic interactions. For this measurement, LArIAT has developed the “thin slice method,” a new technique to measure cross sections with LArTPCs. While moderately higher, our measurement of the π−-Ar total hadronic cross section is generally in agreement with the GEANT4 prediction.Fermi Research Alliance, LLC (FRA) DE-AC02-07CH11359National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 233511/2014-8Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 16/22738-0Polish National Science Centre 2013/09/N/ST2/02793UK Research & Innovation (UKRI)Science & Technology Facilities Council (STFC)Royal Society of LondonMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science 2510500

Development of a novel, windowless, amorphous selenium based photodetector for use in liquid noble detectors

Detection of the vacuum ultraviolet (VUV) scintillation light produced by liquid noble elements is a central challenge in order to fully exploit the available timing, topological, and calorimetric information in detectors leveraging these media. In this paper, we characterize a novel, windowless amorphous selenium based photodetector with direct sensitivity to VUV light. We present here the manufacturing and experimental setup used to operate this detector at low transport electric fields (2.7-5.2 V/$\mu$m) and across a wide range of temperatures (77K-290K). This work shows that the first proof-of-principle device windowless amorphous selenium is robust under cryogenic conditions, responsive to VUV light at cryogenic temperatures, and preserves argon purity. These findings motivate a continued exploration of amorphous selenium devices for simultaneous detection of scintillation light and ionization charge in noble element detectors

Curva di apprendimento nella scialoendoscopia diagnostica e interventistica per le patologie salivari ostruttive

La scialoendoscopia è un nuovo strumento diagnostico e chirurgico che offre l’opportunità di trattare alcune patologie delle ghiandole salivari con procedure non invasive e con risultati potenzialmente superiori alle precedenti tecniche. Come per tutte le nuove tecniche, per raggiungere rapidamente risultati paragonabili a quelli riportati in letteratura, è indispensabile un corretto programma di formazione che segua una graduale curva di apprendimento. Questo include un appropriato programma diagnostico, una corretta selezione dei pazienti e la conoscenza delle possibili insidie operatorie. Abbiamo eseguito uno studio retrospettivo confrontando le prime 141 procedure (74 parotidee e 67 sottomandibolari) eseguite con questa tecnica nel nostro Dipartimento dal 2009 al 2013 con analoghe esperienze riportate in letteratura. I pazienti sono stati divisi in 3 gruppi: Gruppo A (le prime 49 procedure effettuate), gruppo B (le successive 50), Gruppo C (le ultime 42 procedure effettuate). Fra i tre gruppi non sono state evidenziate differenze statisticamente significative nei tempi medi di durata delle procedure, nella percentuale di ricorrenza della sintomatologia dopo il trattamento, nel numero di pazienti che hanno necessitato di più trattamenti e nell’incidenza di complicanze minori. Non sono state riportate complicanze maggiori. Con l’acquisizione di una maggiore esperienza da parte dei chirurghi si è evidenziato un progressivo calo del numero di interventi eseguiti in anestesia generale rispetto a quelli in anestesia locale (51% vs 18% vs 14%). Solo in tre casi su 130 ghiandole trattate (2.3%) è stato necessario eseguire un’asportazione ghiandolare. Per i calcoli salivari è stato valutato il tipo di tecnica utilizzato per l’estrazione e la percentuale d’insuccesso che era analoga nei tre gruppi (13.6% vs 15% vs 15%). I nostri risultati non differiscono sostanzialmente da quelli riportati in letteratura. Abbiamo risolto la difficoltà iniziale nella cateterizzazione del dotto con esercizi chirurgici su cadavere o su teste di maiale. La mancanza di precisione degli strumenti diagnostici radiologici può essere migliorata autonomizzando il chirurgo nell’esecuzione delle ecografie pre e post-operatorie. Viene infine sottolineata l’opportunità di creare dei centri di scialoendoscopia con un bacino di utenza di circa 1 o 2 milioni di abitanti in modo da concentrare le patologie, far fronte agli elevati costi della strumentazione necessaria e poter guadagnare la necessaria esperienza nelle gestione delle varie tecniche chirurgiche

The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector.

The development and operation of liquid-argon time-projection chambers for neutrino physics has created a need for new approaches to pattern recognition in order to fully exploit the imaging capabilities offered by this technology. Whereas the human brain can excel at identifying features in the recorded events, it is a significant challenge to develop an automated, algorithmic solution. The Pandora Software Development Kit provides functionality to aid the design and implementation of pattern-recognition algorithms. It promotes the use of a multi-algorithm approach to pattern recognition, in which individual algorithms each address a specific task in a particular topology. Many tens of algorithms then carefully build up a picture of the event and, together, provide a robust automated pattern-recognition solution. This paper describes details of the chain of over one hundred Pandora algorithms and tools used to reconstruct cosmic-ray muon and neutrino events in the MicroBooNE detector. Metrics that assess the current pattern-recognition performance are presented for simulated MicroBooNE events, using a selection of final-state event topologies

Calorimetry for low-energy electrons using charge and light in liquid argon

Precise calorimetric reconstruction of 5-50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study of astrophysical neutrinos in DUNE and could enhance the physics reach of oscillation analyses. Liquid argon scintillation light has the potential to improve energy reconstruction for low-energy electrons over charge-based measurements alone. Here we demonstrate light-augmented calorimetry for low-energy electrons in a single-phase LArTPC using a sample of Michel electrons from decays of stopping cosmic muons in the LArIAT experiment at Fermilab. Michel electron energy spectra are reconstructed using both a traditional charge-based approach as well as a more holistic approach that incorporates both charge and light. A maximum-likelihood fitter, using LArIAT\u27s well-tuned simulation, is developed for combining these quantities to achieve optimal energy resolution. A sample of isolated electrons is simulated to better determine the energy resolution expected for astrophysical electron-neutrino charged-current interaction final states. In LArIAT, which has very low wire noise and an average light yield of 18 pe/MeV, an energy resolution of σ/E≃9.3%/E 1.3% is achieved. Samples are then generated with varying wire noise levels and light yields to gauge the impact of light-augmented calorimetry in larger LArTPCs. At a charge-readout signal-to-noise of S/N≃30, for example, the energy resolution for electrons below 40 MeV is improved by ≈10%, ≈20%, and ≈40% over charge-only calorimetry for average light yields of 10 pe/MeV, 20 pe/MeV, and 100 pe/MeV, respectively

Calibration of the charge and energy loss per unit length of the MicroBooNE liquid argon time projection chamber using muons and protons

We describe a method used to calibrate the position- and time-dependent response of the MicroBooNE liquid argon time projection chamber anode wires to ionization particle energy loss. The method makes use of crossing cosmic-ray muons to partially correct anode wire signals for multiple effects as a function of time and position, including cross-connected TPC wires, space charge effects, electron attachment to impurities, diffusion, and recombination. The overall energy scale is then determined using fully-contained beam-induced muons originating and stopping in the active region of the detector. Using this method, we obtain an absolute energy scale uncertainty of 2% in data. We use stopping protons to further refine the relation between the measured charge and the energy loss for highly-ionizing particles. This data-driven detector calibration improves both the measurement of total deposited energy and particle identification based on energy loss per unit length as a function of residual range. As an example, the proton selection efficiency is increased by 2% after detector calibration

Reconstruction and measurement of (100) MeV energy electromagnetic activity from π0 arrow γγ decays in the MicroBooNE LArTPC

We present results on the reconstruction of electromagnetic (EM) activity from photons produced in charged current νμ interactions with final state π0s. We employ a fully-automated reconstruction chain capable of identifying EM showers of (100) MeV energy, relying on a combination of traditional reconstruction techniques together with novel machine-learning approaches. These studies demonstrate good energy resolution, and good agreement between data and simulation, relying on the reconstructed invariant π0 mass and other photon distributions for validation. The reconstruction techniques developed are applied to a selection of νμ + Ar → μ + π0 + X candidate events to demonstrate the potential for calorimetric separation of photons from electrons and reconstruction of π0 kinematics

Design and construction of the MicroBooNE Cosmic Ray Tagger system

The MicroBooNE detector utilizes a liquid argon time projection chamber (LArTPC) with an 85 t active mass to study neutrino interactions along the Booster Neutrino Beam (BNB) at Fermilab. With a deployment location near ground level, the detector records many cosmic muon tracks in each beam-related detector trigger that can be misidentified as signals of interest. To reduce these cosmogenic backgrounds, we have designed and constructed a TPC-external Cosmic Ray Tagger (CRT). This sub-system was developed by the Laboratory for High Energy Physics (LHEP), Albert Einstein center for fundamental physics, University of Bern. The system utilizes plastic scintillation modules to provide precise time and position information for TPC-traversing particles. Successful matching of TPC tracks and CRT data will allow us to reduce cosmogenic background and better characterize the light collection system and LArTPC data using cosmic muons. In this paper we describe the design and installation of the MicroBooNE CRT system and provide an overview of a series of tests done to verify the proper operation of the system and its components during installation, commissioning, and physics data-taking