Design, construction and operation of the ProtoDUNE-SP Liquid Argon TPC

The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber (LArTPC) that was constructed and operated in the CERN North Area at the end of the H4 beamline. This detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE), which will be constructed at the Sandford Underground Research Facility (SURF) in Lead, South Dakota, U.S.A. The ProtoDUNE-SP detector incorporates full-size components as designed for DUNE and has an active volume of 7 × 6 × 7.2 m3. The H4 beam delivers incident particles with well-measured momenta and high-purity particle identification. ProtoDUNE-SP's successful operation between 2018 and 2020 demonstrates the effectiveness of the single-phase far detector design. This paper describes the design, construction, assembly and operation of the detector components.

Primary Ionization Density Produced by Charged Fragments in the Working Volume of the Fission Chambers

The question of the spatial distribution of ion pairs created by 235U fission fragments in the active volume of the fission chamber has been studied. The formulas of the spatial distribution of ion pairs in cylindrical fission chambers are proposed, which allows you to evaluate correctly the density of ion pairs in any point in the sensitive volume of the fission chamber

INFORMATION AND KINETIC APPROACH TO THE EVALUATION OF STRESS STATE OF VESSELS OPERATING UNDER PRESSURE IN HYDROGEN ENVIRONMENTS

Separation of the influence of various factors on the strength of the material and control parameters is the basis for increasing the diagnostic efficiency. The article describes methods for assessing the state of pressure vessels, features of their damage under conditions of hydrogen absorption, presents data from acoustic emission and ultrasonic testing, compares them, sets out an approach to non-destructive assessment of the strength state of technical objects, based on a multilevel model of time dependences of acoustic emission parameters (AE), the kinetic concept of strength, micromechanics of fracture of discrete media, their relationship with the resource, parameters of fatigue curves and characteristics of the material structure, the problems of the influence of strength and metrological heterogeneity on the information content of control, the sequence of assessing the indicators of the strength state and resource of vessels, the model of strength and metrological heterogeneity of the AE are presented control, explaining the maximum activity of AE during tests in the first periods of operation, a methodology for assessing the strength state of pressure vessels is presented. Demonstration of the effectiveness of the technique is shown as an example of AE testing of an absorber for purifying hydrogen sulfide with a monoethanolamine solution by predicting the resource of its components and comparing the prediction results with the coordinate-altitude level of the adsorber belt, which correlates with the average internal hydrostatic stresses. Approbation of the approach has shown its versatility on the example of effective application for objects with defects of both fatigue and chemical origin under conditions of hydrogenation. Using the example of assessing the state of the most damaged lower belt, it is shown that an increase in the AE activity during hydrogenation of the material occurs mainly due to the growth of the acoustically active volume of the controlled zone, which is not unambiguously associated with the resource, and therefore the activity and energy intensity of the AE should not be considered sufficient a sign of the danger of a defect formed under the influence of hydrogen-containing media.

IDENTIFICATION OF NATURAL OPEN FRACTURES, INDUCED FRACTURES AND MATRIX PERMEABILITY IN CARBONATES WHILE DRILLING

The economic feasibility of a well drilled in tight carbonates is extremely dependent on the level of fracture permeability; hard and dense carbonate formations may not be considered as net pay without the presence of fractures. The evaluation of fractures is a key to reservoir effectiveness characterization for well drilling, completion, development and stimulation of fractured reservoirs. While knowledge of the geological conditions and regional stress is helpful to estimate the characteristics of the natural fracture system in a given reservoir, the true extent of the natural open fracture system in any specific location is typically unknown. Several methods are available to the industry to identify natural fractures near the wellbore, including acoustic and resistivity image logs. In some cases, the poor-quality results of these techniques do not provide reliable information and such data cannot be available in all the wells. When minor downhole losses are accurately detected, it is possible to locate and characterize the natural open fractures intersected by the drill bit while drilling operations. The differential flow (Flow-out minus Flow-in) and the Active Volume System are continually monitored during drilling and integrated with drilling and hydraulic parameters. These readings are processed in a computer-based, data-acquisition system to form a compensated delta-flow signal that identifies the occurrence of downhole fluid losses. The differential flow is measured accurately through a dedicated Coriolis type flow-meter with a Limit Of Detection up to 10 l/min. By accurately detecting and measuring the downhole micro-losses instantaneously at the surface, the responses would be compared to predefined models for fracture characterization; that enables identification of different types of fractures (open natural, induced fractures). The system can detect very fine micro-fractures that might not be visible with wireline images; fracture density plots can then be created to highlight the fracture concentration along the well. Drilling deep wells in Kuwait is challenging due to high pressure, high-temperature formations, with the Bottom Hole Pressure of +15kpsi and Bottom Hole Temperature of +150 Centigrade degrees. In conventional surface systems, the loss detection relies on the Active Volume System and the Paddle type Flow-out sensor; however, these systems usually fail to identify the minor mud losses associated to open fractures. Especially for active pits with a big surface, it is almost impossible to identify few millimetres of mud level decrease and during fluid transfers, mud conditioning will make the job even more difficult to identify minor losses. With flow paddle type of sensors, the flow out information is not displayed as a calibrated value but rather as a percentage of full scale, which can be difficult to interpret. Instead, dedicated Coriolis type flowmeters properly installed, can identify flow rate changes accurately, regardless of any transfer of mud, water or diesel between pits. By applying this technique, it is possible to identify fractures while drilling in different types of wells, such as vertical, highly deviated and horizontal. The data were validated initially through core and image logs and further applied in next drilling campaigns.

Infrared photoconduction at the diffusion length limit in HgTe nanocrystal arrays

Narrow band gap nanocrystals offer an interesting platform for alternative design of low-cost infrared sensors. It has been demonstrated that transport in HgTe nanocrystal arrays occurs between strongly-coupled islands of nanocrystals in which charges are partly delocalized. This, combined with the scaling of the noise with the active volume of the film, make case for device size reduction. Here, with two steps of optical lithography we design a nanotrench which effective channel length corresponds to 5–10 nanocrystals, matching the carrier diffusion length. We demonstrate responsivity as high as 1 kA W−1, which is 105 times higher than for conventional µm-scale channel length. In this work the associated specific detectivity exceeds 1012 Jones for 2.5 µm peak detection under 1 V at 200 K and 1 kHz, while the time response is as short as 20 µs, making this performance the highest reported for HgTe NC-based extended short-wave infrared detection.

FET-PET radiomics in recurrent glioblastoma: prognostic value for outcome after re-irradiation?

Purpose The value of O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-positron emission tomography (PET)-radiomics in the outcome assessment of patients with recurrent glioblastoma (rGBM) has not been evaluated until now. The aim of this study was to evaluate whether a prognostic model based on FET-PET radiomics features (RF) is feasible and can identify rGBM patients that would most benefit from re-irradiation. Methods We prospectively recruited rGBM patients who underwent FET-PET before re-irradiation (GLIAA-Pilot trial, DRKS00000633). Tumor volume was delineated using a semi-automatic method with a threshold of 1.8 times the standardized-uptake-value of the background. 135 FET-RF (histogram parameters, shape and texture features) were extracted. The analysis involved the characterization of tumor and non-tumor tissue with FET-RF and the evaluation of the prognostic value of FET-RF for time-to-progression (TTP), overall survival (OS) and recurrence location (RL). Results Thirty-two rGBM patients constituted our cohort. FET-RF discriminated significantly between tumor and non-tumor. The texture feature Small-Zone-Low-Gray-Level-Emphasis (SZLGE) showed the best performance for the prediction of TTP (p = 0.001, satisfying Bonferroni-multiple-test significance level). Additionally, two radiomics signatures could predict TTP (TTP-radiomics-signature, p = 0.001) and OS (OS-radiomics-signature, p = 0.038). SZLGE and the TTP-radiomics-signature additionally predicted RL. Specifically, high values for TTP-radiomics-signature and for SZLGE indicated not only earlier progression, but also a RL within the initial FET-PET active volume. Conclusion Our findings suggest that FET-PET radiomics could contribute to the prognostic assessment and selection of rGBM-patients benefiting from re-irradiation. Trial registration DRKS00000633. Registered on 8th of December in 2010. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00000633.

A Prosthetic Socket with Active Volume Compensation for Amputated Lower Limb

Typically, the actual volume of the residual limb changes over time. This causes the prosthesis to not fit, and then pain and skin disease. In this study, a prosthetic socket was developed to compensate for the volume change of the residual limb. Using an inflatable air bladder, the proposed socket monitors the pressure in the socket and keeps the pressure distribution uniform and constant while walking. The socket has three air bladders on anterior and posterior tibia areas, a latching type 3-way pneumatic valve and a portable control device. In the paper, the mechanical properties of the air bladder were investigated, and the electromagnetic analysis was performed to design the pneumatic valve. The controller is based on a hysteresis control algorithm with a closed loop, which keeps the pressure in the socket close to the initial set point over a long period of time. In experiments, the proposed prosthesis was tested through the gait simulator that can imitate a human’s gait cycle. The active volume compensation of the socket was successfully verified during repetitive gait cycle using the weight loads of 50, 70, and 90 kg and the residual limb model with a variety of volumes. It was confirmed that the pressure of the residual limb recovered to the initial state through the active control. The pressure inside the socket had a steady state error of less than 0.75% even if the volume of the residual limb was changed from −7% to +7%.

Sensitivity of direct detection experiments to neutrino magnetic dipole moments

With large active volume sizes dark matter direct detection experiments are sensitive to solar neutrino fluxes. Nuclear recoil signals are induced by 8B neutrinos, while electron recoils are mainly generated by the pp flux. Measurements of both processes offer an opportunity to test neutrino properties at low thresholds with fairly low backgrounds. In this paper we study the sensitivity of these experiments to neutrino magnetic dipole moments assuming 1, 10 and 40 tonne active volumes (representative of XENON1T, XENONnT and DARWIN), 0.3 keV and 1 keV thresholds. We show that with nuclear recoil measurements alone a 40 tonne detector could be as competitive as Borexino, TEXONO and GEMMA, with sensitivities of order 8.0 × 10−11μB at the 90% CL after one year of data taking. Electron recoil measurements will increase sensitivities way below these values allowing to test regions not excluded by astrophysical arguments. Using electron recoil data and depending on performance, the same detector will be able to explore values down to 4.0 × 10−12μB at the 90% CL in one year of data taking. By assuming a 200-tonne liquid xenon detector operating during 10 years, we conclude that sensitivities in this type of detectors will be of order 10−12μB. Reducing statistical uncertainties may enable improving sensitivities below these values.