No abstract

Proportional electroluminescence (EL) in noble gases is used in two-phase detectors for dark matter searches to record (in the gas phase) the ionization signal induced by particle scattering in the liquid phase. The “standard” EL mechanism is considered to be due to noble gas excimer emission in the vacuum ultraviolet (VUV). In addition, there are two alternative mechanisms, producing light in the visible and near infrared (NIR) ranges. The first is due to bremsstrahlung of electrons scattered on neutral atoms (“neutral bremsstrahlung”, NBrS). The second, responsible for electron avalanche scintillation in the NIR at higher electric fields, is due to transitions between excited atomic states. In this work, we have for the first time demonstrated two alternative techniques of the optical readout of two-phase argon detectors, in the visible and NIR range, using a silicon photomultiplier matrix and electroluminescence due to either neutral bremsstrahlung or avalanche scintillation. The amplitude yield and position resolution were measured for these readout techniques, which allowed to assess the detection threshold for electron and nuclear recoils in two-phase argon detectors for dark matter searches. To the best of our knowledge, this is the first practical application of the NBrS effect in detection science.

Design and construction of a new detector to measure ultra low radioactiveisotope contamination of argon Article (Accepted Version) http://sro.sussex.ac.uk

Aria is a plant hosting a $${350}\,\hbox {m}$$ 350 m cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of $${^{39}\hbox {Ar}}$$ 39 Ar in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed, $${^{39}\hbox {Ar}}$$ 39 Ar is a $$\beta $$ β -emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.

A: We report on the cryogenic characterization of Red Green Blue -High Density (RGB-HD) SiPMs developed at Fondazione Bruno Kessler (FBK) as part of the DarkSide program of dark matter searches with liquid argon time projection chambers. A cryogenic setup was used to operate the SiPMs at varying temperatures and a custom data acquisition system and analysis software were used to precisely characterize the primary dark noise, the correlated noise, and the gain of the devices. We demonstrate that FBK RGB-HD SiPMs with low quenching resistance (RGB-HD-LR q ) can be operated from 40 K to 300 K with gains in the range 10 5 to 10 6 and noise rates at a level of around 1 Hz/mm 2 . K: Cryogenic detectors; Photon detectors for UV, visible and IR photons (solid-state); Photon detectors for UV, visible and IR photons (solid-state) (PIN diodes, APDs, Si-PMTs, G-APDs, CCDs, EBCCDs, EMCCDs etc) A X P : 1705.07028 JINST 12 P09030Contents 1 Introduction 1 2 RGB-HD SiPMs 1 3 Setup and analysis 2 4 Results 3 5 Conclusions 6

No abstract

The relations for calculus of: 10M HNO3 solution flow, isotopic transport, 15N molar fraction at the bottom of the separation column, product flow, interphasic transfer velocity, height equivalent to the theoretical plate and sulfur dioxide flows in both stages of the product refluxer are presented for 15N separation column with different diameters and 10M HNO3 feeding flow rates, operated at pressure up to 1.5 atm. In order to produce the isotope 15N at 99 at. % 15N by isotopic exchange in Nitrox system it is desirable to operate the production plant at biggest flow of 10M HNO3 solution, which allows the 15N production at that concentration on a given plant. That will be possible by operating the plant at pressure as it is shown in this work. At 0.8 atm pressure (1.8 atm absolute) the isotopic separation at higher flow rates would be practically equal with that obtained at lower flow rates and atmospheric pressure. For constant: HETP = 10.85 cm, 15N molar fraction of the feeding 10M HNO3, Nf = 0.00365, and of the product, Np = 0.12, the variation of the primary separation column product and of the 15N production plant, as a function of the feeding flow with 10M HNO3 solution, are also presented.

This paper is a step forward by making real time control system design to monitor and control process variables to ensure its smooth operation and desired reliability. Liquid nitrogen level in the condenser is a core component of isotopic separation process to obtain (¹³C), so is needed a special focus on monitoring and control. The goal of the work is to design a controller for the liquid nitrogen in the condenser of (¹³C) isotope separation column using NI-PXI 1031 (PCI eXtensions for Instrumentation) from National Instruments. The designed ON-OFF controller is implemented in LabVIEW and are discussed the advantages and disadvantages.