Abstract
The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino experiment designed to mainly investigate oscillation parameters, supernova physics and proton decay. Its far ...detector will be composed of four liquid argon time projection chamber (LArTPC) underground modules, in South Dakota-USA, which will detect a neutrino beam produced at Fermilab, 1300 km away, where a near detector will be in place. The second DUNE far detector module, vertical drift, will be a single phase LArTPC with electron drift along the vertical axis with two volumes of 13.5 m × 6.5 m × 60 m dimensions separated by a cathode plane. The charge collection will be performed by two anode planes placed at the top and bottom of the module, each composed by stacked layers of a perforated PCB technology with electrode strips. The photon detection system (PDS) will make use of large size X-Arapuca tiles distributed over three detection planes. One plane will consist of a horizontal arrangement of double sided tiles installed on the high voltage cathode plane and two vertical planes, each placed on the longest cryostat membrane walls. A light active coverage of 14.8% over the cathode and 7.4% over the laterals should allow improvements in the low energy physics range that can be probed in DUNE, especially regarding supernova neutrinos (∼10 MeV). We present the initial characterization of the vertical drift PDS using a Monte Carlo simulation and preliminary studies on its reconstruction capabilities at the MeV scale. The information obtained with the PDS alone should allow determination of a neutrino interaction region with a precision of at least 65 cm for events with deposited energy above 5 MeV and the deposited energy can be reconstructed with precision better than 10%, both at the center of the volume.
The conjecture of Bodmer–Witten–Terazawa suggesting a form of quark matter (Strange Quark Matter) as the ground state of hadronic interactions has been studied in laboratory and astrophysical ...contexts by a large number of authors. If strange stars exist, some violent events involving these compact objects, such as mergers and even their formation process, might eject some strange matter into the interstellar medium that could be detected as a trace signal in the cosmic ray flux. To evaluate this possibility, it is necessary to understand how this matter in bulk would fragment in the form of strangelets (small lumps of strange quark matter in which finite effects become important). We calculate the mass distribution outcome using the statistical multifragmentation model and point out several caveats affecting it. In particular, the possibility that strangelets fragmentation will render a tiny fraction of contamination in the cosmic ray flux is discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Experimental data shows that both ionization charge and scintillation light in LAr depend on the deposited energy density (d
E
/d
x
) and electric field (
E
). Moreover, free ionization ...charge and scintillation light are anticorrelated, complementary at a given (d
E
/d
x
,
E
) pair. We present LArQL, a phenomenological model that provides the anticorrelation between light and charge and its dependence on the deposited energy as well as on the electric field applied. It modifies the Birks’ charge model considering the contribution from the escape electrons at null and low electric fields, and reconciles with Birks’ model prediction at higher fields. Deviations from current Birks’ model are observed for LArTPCs operating at low
E
and for heavily ionizing particles. The LArQL model presents a satisfactory description at d
E
/d
x
and field ranges for interacting particles in LArTPCs and fits well the available data. Improvements via data sets compilation and “global” fits are also interesting features of the model.
The ARAPUCA is a novel technology for the detection of liquid argon scintillation light, which has been proposed for the far detector of the Deep Underground Neutrino Experiment. The X-ARAPUCA is an ...improvement to the original ARAPUCA design, retaining the original ARAPUCA concept of photon trapping inside a highly reflective box while using a wavelength shifting slab inside the box to increase the probability of collecting trapped photons onto a silicon photomultiplier array. The X-ARAPUCA concept is presented and its performances are compared to those of a standard ARAPUCA by means of analytical calculations and Monte Carlo simulations.
The concept of the ARAPUCA device is relatively new and involves increasing the effective area for photon collection of SiPMs by the use of a box with highly reflective internal walls, wavelength ...shifters, and a dichroic filter to allow the light to enter the box and not the leave it. There were a number of tests showing the good performance of this device. Recently an improvement on the original design was proposed: the inclusion of a WLS bar inside the box to guide photons more efficiently to the SiPMs. We present a full simulation of the device using Geant4. We have included all the material properties that are available in the literature and the relevant detailed properties for adequate photon propagation available in the framework. Main results include estimates of detection efficiency as a function of the number, shape, and placing of SiPMs, width of the WLS bar, its possible attenuation, and the existence of a gap between the bar and the SiPMs. Improvement on the efficiency with respect to the original ARAPUCA design is 15–40%. The ARAPUCA simulation has been validated in a number of experimental setups and is a useful tool to help making design choices for future experiments devices.
The ARAPUCA concept has been proposed as a simple and neat solution for increasing the effective collection area of SiPMs through the shifting and trapping of scintillation light in noble liquids, ...thus with great potential for improving timing and calorimetry resolution in neutrino and dark matter search experiments using time projection chambers. It is expected to achieve a single photon detection efficiency larger than 1%. The initial design consists of a box made of highly reflective internal surface material and with an acceptance window for photons composed of two shifters and a dichroic filter. The first shifter converts liquid argon scintillation VUV light to a photon of wavelength smaller than the dichroic cutoff, so the surface is highly transparent to it. When passing through the dichroic filter, it reaches the second shifter which allows the photon to be shifted to the visible region and be detected by the SiPM nested inside it. When it enters the box, the photon will likely reflect a few times, including on the dichroic filter surface, before being detected. We present a full numerical description of the device using a Monte Carlo framework, including characterization of the acceptance window, models of reflection of different materials, and sensor quantum efficiency, that can now be used to further improve the detection efficiency by comparing different geometries, positions of SiPM and materials. Estimates of simulated efficiencies, number of reflections and acquisition time are presented and compared to analytical calculations. Those are very promising results, giving a total efficiency for the detection of scintillation light in liquid argon of 1.7±0.3%. Comparison of the estimated total efficiency with a preliminary result from an experimental test with an ARAPUCA prototype made in Brazil is also presented.
The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control ...device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4-30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems.
O conhecimento das estrelas avançou de maneira fundamental no último século, sendo que hoje podemos descrever os processos envolvidos em seu nascimento, evolução e morte. No entanto, a transposição ...do conhecimento científico estelar para a sala de aula não foi feita de maneira ampla ou tem sido feita em geral de forma fragmentada e parcial. Apresentamos aqui um levantamento sobre os trabalhos desenvolvidos nas últimas décadas para o ensino de Astrofísica Estelar (focado no material disponível em língua portuguesa) de modo a organizar e facilitar o trabalho da ampliação da abordagem deste tópico junto a estudantes, em particular no ensino básico, além de algumas sugestões de aplicações que poderão enriquecer o trabalho dos professores. Apresentamos também uma avaliação crítica do panorama dentro do ensino brasileiro.
Our knowledge about stars has fundamentally advanced over the last century and today we can describe the processes involved in their birth, evolution and death. However, the transposition of stellar scientific knowledge into the classroom has not been done in a broad way or has been done in general in a fragmented and partial way. We present here a survey of the work developed in recent decades for the teaching of Stellar Astrophysics (focused on the material available in Portuguese) in order to organize and facilitate the work of expanding the approach to this topic with students, particularly in basic education, in addition to some suggestions for applications that could enrich the work of teachers. We also present a critical assessment of the panorama within Brazilian education.
We entertain the use of light-dependent resistors as a viable option as measuring sensors in optics laboratory experiments or classroom demonstrations. The main advantages of these devices are their ...essentially very low cost, easy handling and commercial availability, which can make them interesting for instructors with limited resources. Simple calibration procedures were developed indicating a precision of ∼5% for illuminance measurements. Optical experiments were carried out as proof of feasibility for measurements of reflected and transmitted light and its quality results are presented. In particular, the sensor measurements allowed us to verify the angular distribution of a Lambertian reflective material, to observe transmitted and reflected specular light on a glass slab as function of the incoming angle of a light beam, and to estimate glass refractive index with values averaging 1.51 0.06 in satisfactory agreement with the expected 1.52 value.
Abstract
The X-ARAPUCA device is the baseline choice for the photon
detection system of the first far detector module of the DUNE
experiment. We present the results of the first complete
...characterization of a small scale X-ARAPUCA prototype, which is a
slice of a full DUNE module. Its total detection efficiency in
liquid argon was measured with three different ionizing radiations:
α particles, γ's and muons and resulted to be
∼2.2% when the active silicon photomultipliers were biased at
+5.0 V
of over voltage, corresponding to a Photon Detection
Efficiency around 50% at room temperature. This value comfortably
satisfies the requirements of the first DUNE far detector module
(detection efficiency >2.0%) and allows to achieve an energy
resolution comparable to the one achievable with the Time Projection
Chambers for energies below 10 MeV, which is the region relevant
for Supernova neutrino detection.
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