Scintillation light in SBND: simulation, reconstruction, and expected performance of the photon detection system

SBND is the near detector of the Short-Baseline Neutrino program at Fermilab. Its location near to the Booster Neutrino Beam source and relatively large mass will allow the study of neutrino interactions on argon with unprecedented statistics. This paper describes the expected performance of the SBND photon detection system, using a simulated sample of beam neutrinos and cosmogenic particles. Its design is a dual readout concept combining a system of 120 photomultiplier tubes, used for triggering, with a system of 192 X-ARAPUCA devices, located behind the anode wire planes. Furthermore, covering the cathode plane with highly-reflective panels coated with a wavelength-shifting compound recovers part of the light emitted towards the cathode, where no optical detectors exist. We show how this new design provides a high light yield and a more uniform detection efficiency, an excellent timing resolution and an independent 3D-position reconstruction using only the scintillation light. Finally, the whole reconstruction chain is applied to recover the temporal structure of the beam spill, which is resolved with a resolution on the order of nanoseconds

Usefulness of pulsed tissue Doppler for the assessment of left ventricular myocardial function in overt hypthyroidism

BACKGROUND: The aim of this study was to assess the role of tissue Doppler (TD) in the identification of left ventricular (LV) myocardial regionl abnormalities in overt hypothyroidism. METHODS: Fourteen women with newly diagnosed, never treated overt hypothyroidism and 14 healthy women, matched for age, underwent standard echocardiography and pulsed TD, by placing the sample volume at the basal posterior septum and lateral mitral annulus, in the apical 4-chamber view. The myocardial systolic (SM) and diastolic velocities (Em, Am and their ratio) and time intervals (relaxation time [RTm], pre-contraction time [PCTm], contraction time) were measured. RESULTS: The two groups were comparable for body surface area, blood pressure and heart rate. At standard echocardiography, patients with overt hypothyroidism had a significantly greater septal thickness and LV mass index, a longer LV pre-ejection period (PEP), deceleration time and isovolumic relaxation time (IVRT) and a lower E peak velocity and E/A ratio. TD showed a significantly longer PCTm and RTm and a lower Em and Em/Am ratio of both the septum and mitral annulus in overt hypothyroidism. The ratio of the standard Doppler E to Em of the mitral annulus was 5.5 +/- 1.2 in controls and 5.3 +/- 1.7 in overt hypothyroidism (p = NS). In the overall population, PEP, IVRT, PCTm and RTm were correlated negatively with FT3 and FT4, and positively with thyroid-stimulating hormone. After adjusting for age, body surface area and heart rate in separate multivariate analyses, the associations of TD PCTm with the thyroid hormones and thyroid-stimulating hormone were greater than the homologous associations of standard Doppler PEP. CONCLUSIONS: Standard echocardiography confirms itself as a satisfactory diagnostic technique for the identification of LV global dysfunction in overt hypothyroidism. Pulsed TD may be useful to determine the severity of LV myocardial dysfunction in relation to the degree of hormonal impairment

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen