Статистическая модель оценки веса газовых баллонов

Объектом исследования: выборка фактического веса пустого баллона, выборка наполненного газом баллона и выборка веса газа. Цель работы: определить количество баллонов для взвешивания, чтобы определить средний вес газа в баллонах в выборке. В процессе исследования проводилась оценка распределения вероятностей на основе выборочных данных для определения веса газа в баллоне и проверка гипотезы о параметрах нормального распределения. В результате исследования сделан вывод о том, к какому типу распределения подчиняется выборка веса газа в баллонах и определено количество взвешиваний баллонов.The object of research: sample of actual weight of empty gas bottle, sample of filled gas bottle and sample of gas weight. Purpose of research: to quantify gas bottles for weighing in order to determine the average weight of the gas in the gas bottles in the sample. During the research the evaluation of probability distribution, based on the sample data for weighing gas in the gas bottle, was applied; proving of hypothesis concerning parameters of the normal distribution was carried out. As the result of the research comes the conclusion concerning the type of distribution which the sample of gas weight in gas bottles submitted to; the number of weighings of gas bottles was determined

Электропривод регулирующей трубопроводной арматуры на базе синхронного двигателя с постоянными магнитами

Цель работы – создание нового поколения регулирующих взрывозащищенных электроприводов с минимальными габаритными размерами, массой и себестоимостью, не уступающих по точности регулирования и функциональным характеристикам регулирующим электроприводам производства других фирм. В процессе работы был произведен расчет и выбор электропривода. Проведено моделирование и анализ работы привода в разных режимах.The purpose of the work is to create a new generation of regulating explosion-proof electric drives with minimum overall dimensions, weight and cost, which are not inferior in regulation accuracy and functional characteristics to regulating electric drives produced by other companies. During operation electric drive was calculated and selected. Simulation and analysis of the drive operation in different modes were carried out

SAFIR-I: Design and Performance of a High-Rate Preclinical PET Insert for MRI

(1) Background: Small Animal Fast Insert for MRI detector I (SAFIR-I) is a preclinical Positron Emission Tomography (PET) insert for the Bruker BioSpec 70/30 Ultra Shield Refrigerated (USR) preclinical 7T Magnetic Resonance Imaging (MRI) system. It is designed explicitly for high-rate kinetic studies in mice and rats with injected activities reaching 500MBq, enabling truly simultaneous quantitative PET and Magnetic Resonance (MR) imaging with time frames of a few seconds in length. (2) Methods: SAFIR-I has an axial field of view of 54.2mm and an inner diameter of 114mm. It employs Lutetium Yttrium OxyorthoSilicate (LYSO) crystals and Multi Pixel Photon Counter (MPPC) arrays. The Position-Energy-Timing Application Specific Integrated Circuit, version 6, Single Ended (PETA6SE) digitizes the MPPC signals and provides time stamps and energy information. (3) Results: SAFIR-I is MR-compatible. The system’s Coincidence Resolving Time (CRT) and energy resolution are between separate-uncertainty 209.0(3)ps and separate-uncertainty 12.41(02) Full Width at Half Maximum (FWHM) at low activity and separate-uncertainty 326.89(12)ps and separate-uncertainty 20.630(011) FWHM at 550MBq, respectively. The peak sensitivity is ∼1.6. The excellent performance facilitated the successful execution of first in vivo rat studies beyond 300MBq. Based on features visible in the acquired images, we estimate the spatial resolution to be ∼2mm in the center of the Field Of View (FOV). (4) Conclusion: The SAFIR-I PET insert provides excellent performance, permitting simultaneous in vivo small animal PET/MR image acquisitions with time frames of a few seconds in length at activities of up to 500MBq

Time resolution of a photomultiplier readout system for space application

The performance of a readout system for the synchrotron radiation detector (SRD) is studied. The detector is proposed as part of the Alpha Magnetic Spectrometer experiment, an experiment to fly on the International Space Station (ISS) beginning of 2005. The SRD is designed to detect the synchrotron radiation from electrons and positrons (TeV energy range) produced in the earth's magnetic field. For the planned array of scintillators and photomultipliers a readout system is chosen, which is compact, space qualified and has a low- power consumption. The low-power chip APV, originally designed for the CMS experiment at LHC (CERN), is foreseen for the readout. To overcome the diffuse background from photons and charged particles the SRD readout must have a time resolution better than 10 ns. The intrinsic time resolution (sigma from Gauss fit) of the APV25-S0 was found to be 0.46 +or- 0.01 and 0.68 +or-0.02 ns for the APVM. whereas the time resolution of the photomultiplier-APV readout system was measured to be 2.73 +or- 0.10 ns for the APV25-S0 and 2.90 +or- 0.21 ns for the APVM. The investigated timing capabilities of the photomultiplier-APV readout system show that the APV chip is suitable for the SRD readout

Compact MR-compatible DC-DC converter module

The SAFIR collaboration is developing a high rate positron emission tomography insert for a preclinical 7 T magnetic resonance imaging (MRI) device. To meet the desired performance figures, a large number of readout channels (≈15000) and integration of data digitisation into the insert are required. Consequently, the insert will consume about 1.3 kW of input power at low voltages (≤ 3.3 V). This corresponds to large supply currents of several 100 A, requiring heavy and bulky supply cables. To overcome these problems we developed a compact and MR-compatible DC-DC stepdown converter module. Our converter is based on an air core inductor and is optimised for low electromagnetic emissions. It has an input voltage range from 6 V to 24 V and provides an adjustable output voltage from 1 V almost up to the input voltage. The maximum continuous output current is 6 A. We measured conversion efficiencies between 70% and 87% depending on output load and input voltage. For the operation conditions foreseen (16 V input voltage, 2.4 V output voltage and 3 A output current), we achieved an efficiency of 83.8%. Our tests inside the MRI demonstrated the compatibility between the MRI system and the step-down converters developed. No mutual interference was observed. The signal-to-noise ratio of the MRI remains unaltered, independent of the activity of the step-down converter under any operation condition and no effect on the operation of the DC-DC converter was observed. This successful test of an MR-compatible DC-DC converter creates new opportunities for the power supply of complex hardware inside an MRI. 49 of the DC-DC converters will be used in our SAFIR PET insert, but they can also be used in other applications with high power demand in environments with strong magnetic fields.ISSN:1748-022

Measurements with an MSGC Hodoscope Using the PreMux128 Frontend Chip

We report on the performance of a hodoscope containing 3 large area micro strip gas chambers ( MSGCs). The results of the measurements in a test beam experiment and with cosmics rays are presented. As counting gas Ar/Propan ( 60/40) and Ar/DME ( 50/50) provided by a closed gas system that recycles and purifies the gas was used. The detectors were equipped with the PreMux128 chip, a multiplexer chip using double correlated sampling for signal processing. The influence of this method for the operation with MSGCs is discussed

A Test Setup for Quality Assurance of Front End Hybrids

The APV Readout Control (ARC) Test Setup is a compact, cost efficient test and diagnostic tool which is suited for full operation and characterisation of FE hybrids and Si-Detector modules. This note gives an overview of the construction and the features of the test facility. Based on the ARC setup and the experience gained with one prototype FE hybrid, possible quality assurance scenarios for short and long term tests of FE hybrids are also presented

Geiger-mode avalanche photodiodes as photodetectors in Cherenkov astronomy

The progress in the development of Geiger-mode avalanche photodiodes (G-APD) has resulted in devices which show great promise for Imaging Atmospheric Cherenkov Telescopes (IACT). In the course of the First G-APD Camera Test (FACT) project with the purpose to construct a G-APD based camera, their characteristics are analysed and measured in detail. The angle dependence of the photon detection efficiency was measured and found to be flat. The effects of saturation and cross-talk on the reconstruction of the number of detected photons was studied. Since these effects are of a statistical nature, the reconstructed number is limited in its precision. For small numbers of photons, crosstalk is the limiting factor. For photon numbers comparable to or higher than the number of cells of the G-APD, the main limitation is the saturation