AC Josephson properties of phase slip lines in wide tin films

Current steps in the current-voltage characteristics of wide superconducting Sn films exposed to a microwave irradiation were observed in the resistive state with phase slip lines. The behaviour of the magnitude of the steps on the applied irradiation power was found to be similar to that for the current steps in narrow superconducting channels with phase slip centers and, to some extent, for the Shapiro steps in Josephson junctions. This provides evidence for the Josephson properties of the phase slip lines in wide superconducting films and supports the assumption about similarity between the processes of phase slip in wide and narrow films.Comment: 7 pages, 2 figures, to be published in Supercond. Sci. Techno

Laser Scanning Microscopy of HTS Films and Devices

The work describes the capabilities of Laser Scanning Microscopy (LSM) as a spatially resolved method of testing high_Tc materials and devices. The earlier results obtained by the authors are briefly reviewed. Some novel applications of the LSM are illustrated, including imaging the HTS responses in rf mode, probing the superconducting properties of HTS single crystals, development of twobeam laser scanning microscopy. The existence of the phase slip lines mechanism of resistivity in HTS materials is proven by LSM imaging.Comment: 17 pages, 21 figures, Submitted to Fizika Nizkikh Temperatur (Low Temperature Physics

Dzyaloshinskii--Moriya interaction: How to measure its sign in weak ferromagnetics?

Three experimental techniques sensitive to the sign of the Dzyaloshinskii--Moriya interaction are discussed: neutron diffraction, Moessbauer gamma-ray diffraction, and resonant x-ray scattering. Classical examples of hematite (alpha-Fe2O3) and MnCO3 crystals are considered in detailComment: 5 pages, 1 figure; to be published in JETP Letter

Multilayer film shields for the protection of PMT from constant magnetic field

This is the Published Version made available with the permission of the publisher.Photomultiplier tubes (PMTs) are widely used in physical experiments as well as in applied devices. PMTs are sensitive to magnetic field, so creation of effective magnetic shields for their protection is very important. In this paper, the results of measurements of shielding effectiveness of multilayer film magnetic shields on PMT-85 are presented. Shields were formed by alternating layers of a material with high magnetic permeability (Ni-Fe) and high electric conductivity—Cu. The maximum number of bilayers reached 45. It is shown that in weak magnetic fields up to 0.5 mT, the output signal amplitude from PMT-85 does not change for all used multilayer shields. In strong magnetic field of 2–4 mT, the output signal amplitude decrease with 10%–40% depending from the number of layers in the shield. The Pulse distribution of PMT-85 in magnetic field 0.2–4 mT slightly changed in the range 1.1%–1.3% for the case when the number of layers do not exceed 10 and practically did not change for a shield with 45 double layers

Quantum superposition of three macroscopic states and superconducting qutrit detector

Superconducting quantum coherent circuits have opened up a novel area of fundamental low-temperature science since they could potentially be the element base for future quantum computers. Here we report a quasi-three-level coherent system, the so-called superconducting qutrit, which has some advantages over a two-level information cell (qubit), and is based on the qutrit readout circuit intended to measure individually the states of each qubit in a quantum computer. The designed and implemented radio-frequency superconducting qutrit detector (rf SQUTRID) with atomic-size ScS-type contact utilizes the coherent-state superposition in the three-well potential with energy splitting Delta E_01/k_B=1.5 K at the 30th quantized energy level with good isolation from the electromagnetic environment. The reason why large values of Delta E_01 (and thus using atomic-size Nb-Nb contact) are required is to ensure an adiabatic limit for the quantum dynamics of magnetic flux in the rf SQUTRID.Comment: 9 pages, 5 figures, in v.3: text extended, inset in figure 1 (the device design) adde

Multilayer film shields for the protection of PMT from constant magnetic field

This is the Published Version made available with the permission of the publisher.Photomultiplier tubes (PMTs) are widely used in physical experiments as well as in applied devices. PMTs are sensitive to magnetic field, so creation of effective magnetic shields for their protection is very important. In this paper, the results of measurements of shielding effectiveness of multilayer film magnetic shields on PMT-85 are presented. Shields were formed by alternating layers of a material with high magnetic permeability (Ni-Fe) and high electric conductivity—Cu. The maximum number of bilayers reached 45. It is shown that in weak magnetic fields up to 0.5 mT, the output signal amplitude from PMT-85 does not change for all used multilayer shields. In strong magnetic field of 2–4 mT, the output signal amplitude decrease with 10%–40% depending from the number of layers in the shield. The Pulse distribution of PMT-85 in magnetic field 0.2–4 mT slightly changed in the range 1.1%–1.3% for the case when the number of layers do not exceed 10 and practically did not change for a shield with 45 double layers

SiPM-based azimuthal position sensor in ANITA-IV Hi-Cal Antarctic balloon experiment

Hi-Cal (High-Altitude Calibration) is a balloon-borne experiment that will be launched in December, 2016 in Antarctica following ANITA-IV (Antarctic Impulsive Transient Antenna) and will generate a broad-band pulse over the frequency range expected from radiation induced by a cosmic ray shower. Here, we describe a device based on an array of silicon photomultipliers (SiPMs) for determination of the azimuthal position of Hi-Cal. The angular resolution of the device is about 3 degrees. Since at the float altitude of ~38 km the pressure will be ~0.5 mbar and temperature ~ − 20 °C, the equipment has been tested in a chamber over a range of corresponding pressures (0.5 ÷ 1000) mbar and temperatures (−40 ÷ +50) °C

ПОЛУЧЕНИЕ И СВОЙСТВА ТОНКОПЛЕНОЧНЫХ КОМПОЗИЦИОННЫХ ПОЛОВОЛОКОННЫХ МЕМБРАН ДЛЯ УЛЬТРАФИЛЬТРАЦИИ С НИЗКИМ НОМИНАЛЬНЫМ МОЛЕКУЛЯРНО-МАССОВЫМ ПРЕДЕЛОМ ОТСЕЧЕНИЯ

Fullerenol C60(OH)24 was incorporated into a polyamide (PA) selective layer to develop novel thin film nanocomposite (TFN) hollow fiber membranes for low molecular weight cut-off ultrafiltration. TFN membranes were fabricated using the interfacial polycondensation technique by alternately pumping a fullerenol dispersion into the triethylenetetramine (TETA) aqueous solution and the isophthaloyl chloride solution into hexane through polysulfone hollow fiber membranes. The contact angle of the skin layer was found to decrease sharply from 34 to 21° when the concentration of fullerenol increases up to 0.5 wt. % in the TETA aqueous solution. Antifouling properties of the PA/fullerenol membranes were found to be superior to the initial membrane. The maximum fouling recovery ratio was observed for the TFN membrane with 0.3–0.75 wt. % of fullerenol in the TETA aqueous solution. Тонкопленочные композиционные мембраны (ТКМ) для ультрафильтрации с низким номинальным молекулярно-массовым пределом отсечения были получены при введении добавок фуллеренола C60(OH)24 в селективный полиамидный (ПА) слой, сформированный методом межфазной поликонденсации при использовании в качестве подложки половолоконной ультрафильтрационной мембраны на основе полисульфона. Межфазную поликонденсацию с образованием тонкого полиамидного слоя проводили при последовательной фильтрации раствора триэтилентетрамина (ТЭТА) в воде и раствора изофталоилхлорида в гексане через половолоконную мембрану. При увеличении концентрации фуллеренола в водном растворе ТЭТА угол смачивания селективного слоя уменьшается с 34 до 21°. Показано, что устойчивость к засорению ТКМ ПА/фуллеренол выше, чем исходной немодифицирован- ной мембраны. Мембраны, полученные с использованием 0,3–0,75 % дисперсий фуллеренола в растворе ТЭТА, характеризовались максимальным значением восстановления потока после фильтрации раствора лизоцима.