Development of high granulated straw chambers of large sizes

We have developed the baseline design for the straw drift tube tracking detectors for high-rate environment application. The low-mass inner straw elements and the technology of the multianode straws assembly were devised and checked. The prototype chamber was constructed and studied. The granularity of similar chambers can be reduced to 1 cm². The text was submitted by the authors in English.     

Separation of Nitrogen Isotopes by Thermal Diffusion

The prototype of a thermal diffusion column for the use as basic unit in a N¹⁴N¹⁵ cascade is described. The hot wire separation column consists of a brass tube of effective length of 250 cm and inner diameter of 10 mm. Four columns are connected in series on a square cascade, the separation factors of which are compared with the values obtained by other investigators.     

New type of drift tubes for gas-discharge detectors operating in vacuum: Production technology and quality control

A device for fabricating thin-wall (straw) drift tubes using polyethylene terephthalate film 36 μm thick by ultrasonic welding is described together with the technique for controlling their quality. The joint width amounts to 0.4–1.0 mm. The joint breaking strength is 31.9 kg/mm². The argon leakage from a tube of volume 188.6 cm³ under a pressure gradient of 1.0 atm does not exceed 0.3 × 10^–3 cm³/min, which is mainly related to the absence of metallization in the joint vicinity. The high strength, the low tensile creep due to the absence of glued layers, the small value of gas leakage makes the new tubes capable of reliable and long-term operation in vacuum, which is confirmed by the operation of 7168 straw tubes for two years in the NA62 experiment.     

Prototype of a large neutron detector based on MWPC

A prototype of large-area position sensitive neutron detector was designed and constructed according to the requirements of the Small-Angle Scattering spectrometer of China Spallation Neutron Source(CSNS).The detector was based on the 3He neutron convertor and MWPC with an effective area of 650 mm×650 mm.A prototype was completed and tested with 55Fe X-ray.The high-pressure vessel was designed and constructed with high-strength aluminum alloy.A position resolution of about 4.6mm×2.3 mm(FWHM)and efficiency65%for neutrons with wavelength of 1.8?was determined after the operational gas filled.     

Gas-filled position-sensitive detectors of thermal neutrons at the Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences

The manufacturing line for the development and fabrication of position-sensitive detectors of thermal neutrons has been organized at the Petersburg Nuclear Physics Institute of the Russian Academy of Sciences. Three detectors with sensitive regions 300 × 170 (prototype), 200 × 200, and 300 × 300 mm in size have been constructed to date. The detectors represent multiwire proportional chambers with cathode data readout to a delay line. The devices are filled with the ³He/CF₄ gas mixture. These detectors are intended for modernizing the detector systems of the Vector and Membrana-2 diffractometers (VVR-M reactor, Konstantinov Petersburg Nuclear Physics Institute of the Russian Academy of Sciences, Gatchina, Russia).     

Growth rates in modern speleothems from Santana Cave,Brazil, by the 210Pb-method

The Santana Cave is located at the Upper Ribeira Touristic State Park (PETAR-Parque Estadual Turístico do Alto Ribeira) in southern São Paulo State, Brazil. This paper describes ²¹⁰Pb activity concentration data in soda straw stalactites samples collected at Salão das Flores in Santana Cave that is a fossil tributary of the cave river. Non-expensive alpha counting following some analytical steps for extracting and depositing ²¹⁰Po were used for providing the ²¹⁰Pb data. In the analyzed samples, ²¹⁰Pb values of increasingly older samples fitted an exponential curve, thus suggesting that the production of ²¹⁰Pb has been constant with time. Also, the near-ideal fit indicated that the growth was uniform and there was no break in the continuous growth. The soda straw growth rates were determined from the best fit to the exponential curve through the ²¹⁰Pb activity concentration. The results of the measurements allowed estimate a longitudinal rate corresponding to 1.3 mm/yr and a lateral rate of 0.01 mm/yr, which permitted calculate times of 70 years and 317–498 years for their formation, respectively. The lateral growth rate is compatible with values from studies of chemical weathering rates held under laboratory and natural conditions.     

High conversion efficiency solar laser pumping by a light-guide/2D-CPC cavity

A simple and efficient light-guide/2D-CPC solar pumping approach is proposed. A fused silica light-guide assembly is used to transmit 6 kW concentrated solar power from the focal spot of a large parabolic mirror to the entrance aperture of a 2D-CPC pump cavity, where a long and thin Nd:YAG rod is efficiently pumped. Numerical calculations are made for different light-guides, 2D-CPC cavities and laser rods. The laser output power is investigated through finite element analysis. With 4 mm diameter rod, the maximum calculated laser power of 75.8 W is obtained, corresponding to the conversion efficiency of more than 11 W/m². The tracking error dependent laser power losses are lower than 4%. A small scale prototype was constructed and tested, reaching 8.1 W/m² conversion efficiency.     

Unusual sequence of commensurate-incommensurate phase transitions observed in KLiSO4

An unusual structural phase transition sequence is observed in KLiSO₄ by EPR: high temperature prototype phase -incommensurately modulated phase - commensurately modulated phase - incommensurately modulated phase - low temperature prototype phase (reentrant phase). The low temperature phase has the same symmetry C⁶₆ of the high temperature prototype phase. The main feature of the modulation are rotations of the sulphate tetrahedra, which were precisely determined in the commensurately modulated phase.     

Bi-SQUID arrays and parallel SQIF structures for active electrically small antennas

The basic physics of the development of broadband active electrically small superconductive antennas for the subgigahertz and gigahertz frequency ranges, based on series arrays with cells characterized by a highly linear voltage response to the magnetic component B of an electromagnetic signal, are under consideration. As such cells, bi-SQUIDs and cells based on two parallel SQIF structures that are differentially connected are proposed. Series arrays of cells with linear voltage response, including an antenna prototype, are fabricated using standard niobium technology with a critical current density of Josephson junctions of 4.5 kA/cm² and are studied experimentally. The data obtained allow estimation of the achievable dV/dB conversion factor and the sensitivity ??B for an antenna integrated with a magnetic flux converter, placed on an available area of 3.3 × 3.3 mm of a chip 5 × 5 mm in size. These values are found to be 10 ??V/nT and 20 fT/Hz^1/2, respectively. The conversion factor increases in proportion with the area a ² occupied by the antenna with a square flux converter, and the sensitivity is improved as a ^?3/2.     

低山丘陵坡耕地秸秆覆盖轮耕土壤WSOC的荧光特征

为了提高坡耕地的秸秆还田效率，增加土壤有机质，探索一种适于坡耕地的基于种养结合的保护性耕作方式。采用田间小区试验，研究了秸秆覆盖轮耕技术（包括当季秸秆覆盖+休闲、上季秸秆覆盖+旋耕）与常规耕作（秸秆移除后旋耕）对土壤水溶性有机碳（WSOC）荧光特征及团聚体有机碳的影响。结果表明：砂质暗棕壤坡耕地秸秆覆盖旋耕（SRT）、秸秆覆盖休闲（SFT）与秸秆不还田的常规耕作（CRT）处理土壤WSOC均解析出C1，C2，C3和C4等4组荧光组分，主要为紫外光区与可见光区类富里酸（Peak A 和Peak C）、类胡敏酸（F）和短波类色氨酸（类蛋白B、D峰）等成分。秸秆覆盖旋耕处理提高了类富里酸（Peak A和Peak C）和类蛋白组分C4含量，C1和C2组分较覆盖休闲和常规耕作分别提高112.73%，109.35%和107.77%，66.07%，C4组分较SFT与CRT处理提高28.26%和42.31%，差异显著，而常规耕作处理来自于自生源腐殖质组分的胡敏酸C3含量增加，较覆盖旋耕和覆盖休闲处理分别增加16.76%和49.74%；0～20 cm耕层土壤团聚体有机物主要分布在<0.053 mm的矿物质结合态（MOM）中，平均占比为63.90%，其次为0.25～0.053 mm细颗粒态有机物（oPOM），占比为23.8%，粗颗粒态有机物（>0.25 mm）中含量最低，仅为11.2%；与秸秆不还田比较，坡耕地秸秆覆盖还田增加了植物来源的新鲜有机质的形成，表现为＞0.053 mm的闭蓄态有机碳（oPOC）含量的增加，以覆盖旋耕处理oPOC增加较大，而秸秆不还田的CRT处理增加了MOM占比；覆盖旋耕处理FI和HIX值增大，土壤腐殖质积累趋势增强，为低山丘陵区坡耕地实施秸秆覆盖还田的保护性耕作技术提供了科学依据。     

A compact TOF-SANS using focusing lens and very cold neutrons

We are developing a high-resolution small angle neutron scattering instrument for very cold neutrons (VCN). Our concept includes a magnetic lens for focusing of the beam at the detector plane. The lens consists of one permanent-magnet sextupole array rotating outside another stationary sextupole array, to focus a pulsed white beam of neutrons. Thus the instrument operates in time of flight mode. The prototype magnetic lens has a bore of 15 mm diameter and length of 66 mm, producing a magnetic field gradient oscillating from 1.5×10⁴ to 5.9×10⁴ T/m², with frequency ≤25 Hz. A torque-canceling magnet around the lens suppresses the torque of rotation from the outer array to 1/3.We have demonstrated the performance of the lens, over wavelength range from 30 to 48 Å, on the PF2-VCN beam line at the Institut Laue-Langevin, France. The focused beam image was the same size as the source, without chromatic aberration, with focal length of 1.14 m. We also studied the performance of this configuration for high-resolution SANS, in a compact geometry (just 5 m long). The measurable q range of this system was 0.009 Å⁻¹≤q≤0.3 Å⁻¹ or 0.004 Å⁻¹≤q≤0.08 Å⁻¹ for sample to detector distances of 100 and 465 mm, respectively. Here, we present the results of our lens characterization study along with the SANS results on a tri-block copolymer (F127 Pluronic) and on a stretched polymer blend (with the Shish-Kebab structure).     

Investigations of elastic properties at very low frequencies: Method and behaviour of (TMA)2ZnCl4

Abstract

A new apparatus to perform longitudinal elastic strain measurements over a frequency range from 10^?4 Hz to 10¹ Hz is presented. First results of measurements on TMAZC with the prototype of this device are given. These results will be discussed in connection with the new methods.     

A miniature prototype of a resonance photoacoustic cell for gas sensing

We present a miniature prototype of a resonance photoacoustic cell with a banana-shaped internal cavity with a volume of less than ～5 mm³. The cell design and the experimental setup used for testing operational characteristics of the prototype are described. The results of testing the prototype in the experiments on photoacoustic detection of radiation absorption by ammonia in a nitrogen flow by using a single-mode diode laser generating radiation near ～1.53 μm are presented. The amplitude-frequency characteristic of the photoacoustic response induced by absorption of radiation in the presence and absence of ammonia is analyzed. The experiment revealed that sensitivity of gas sensing is limited only by the microphone noise. The measured noise-limited minimal detectable absorption was found to be about 8.48 × 10^?8 cm^?1 W Hz^?1/2.     

IAE-3 and IAE-6 high resolution photographic materials for recording laser radiation in the IR-region

New photographic materials for recording the radiation of injection lasers (λ=840 nm) with a sensitivity of ?10^-4 J/sm² and a resolution of 4300 lines/mm, and photographic materials for recording the radiation in the region of 1060 nm with a sensitivity of ?10^-4 J/sm² and a resolution of 1000 lines/mm are described.     

Full-scale prototype of the circular track detector for the multipurpose detector facility at the NICA acceleration complex

The development of the NICA heavy ion collider, which is now under way, assumes the development of a Multipurpose Detector (MPD), including an end-cap tracker (EC) (which can be a wheel-type tracker based on thin-wall drift tubes (straws) similar to the inner detector of the transition radiation tracker (TRT) in the ATLAS experiment). The identical front and back tracker modules mounted behind the TPC are to ensure the detection of Au-Au ion collision products in the pseudorapidity range from 1.4 to 2.1 with good track parameters of reconstructed events. Each module will contain 60 circular straw planes and maximum straw occupancy will be no higher than 0.2 particle per collision. The NICA EC is substantially different from its analogue and requires a certain amount of R&D. The first results from applying new technology to make a full-scale prototype of the circular EC detector for NICA are presented.     

A practical multinuclear transceiver volume coil for in vivo MRI/MRS at 7 T

A practical multinuclear transceiver RF volume coil with improved efficiency for in vivo small animal ¹H/¹³C/²³Na MR applications at the ultrahigh magnetic field of 7 T is reported. In the proposed design, the coil's resonance frequencies for ¹H and ¹³C are realized by using a traditional double-tuned approach, while the resonant frequency for ²³Na, which is only some 4 MHz away from the ¹³C frequency, is tuned based upon ¹³C channel by easy-operating capacitive “frequency switches”. In contrast to the traditional triple-tuned volume coil, the volume coil with the proposed design possesses less number of resonances, which helps improve the coil efficiency and alleviate the design and operation difficulties. This coil design strategy is advantageous and well suitable for multinuclear MR imaging and spectroscopy studies, particularly in the case where Larmor frequencies of nuclei in question are not separate enough. The prototype multinuclear coil was demonstrated in the desired unshielded design for easy construction and experiment implementation at 7 T. The design method may provide a practical and robust solution to designing multinuclear RF volume coils for in vivo MR imaging and spectroscopy at ultrahigh fields. Finite difference time domain method simulations for evaluating the design and 7-T MR experiment results acquired using the prototype coil are presented.     

A model for an extensional mode resonator used as a frequency-adjustable vibration energy harvester

In an effort to identify techniques for harvesting energy from ambient vibrations, a prototype device that utilizes stretching piezoelectric film to support a proof mass, with an adjustable support that allows the resonant frequency of the device to be easily altered, has been developed. This extensional mode resonator (XMR) device is described by a model developed in this paper that predicts the power that is harvested as a function of the frequency and amplitude of the external vibration, the elastic and piezoelectric materials properties, and the device geometry. The model provides design guidelines for the effects of device geometry and applied tension through an adjustable support that suggest a strong dependence on mechanical damping and a weak dependence on frequency, as opposed to a bending cantilever device. The model predictions are compared to experimental measures from a prototype device for frequencies between 120 and 180 Hz, and at accelerations between 0.1 and 10 m/s². Up to 9 mW is generated from a device with a mass of ∼82 g, and over the range of frequencies tested the power harvested at 4 m/s² is between 3 and 4 mW.     

Dislocation structure of kcl crystals grown with vibration of the melt

Summary The amplitude at all frequencies was 0.04 mm. Three crystals were grown at each frequency, with seeds of dislocation density D = 6 × 10⁴ cm^–2. Figure 1 shows the frequency dependence of the final D. Each point in Figs. 1 and 2 is the mean from 50 measurements (50 fields of view). At all frequencies except 180 Hz, D was 2–4 times less than that without vibration, while at 100 and 160 Hz it was less by nearly an order of magnitude.The effects of amplitude (0.02 to 0.2 mm) were examined at 100 Hz, the minimum D occurring at 0.1 mm (Fig. 2). At 0.04–0.08 mm, D was less by a factor 3–4 than for crystals grown without vibration, while at 0.1 mm it was less by an order of magnitude, being 2 × 10^–4 cm^–2. The size of the etch pits on crystals grown at amplitudes up to 0.1 mm did not differ from that for crystals grown at rest, but above 0.1 mm the size increased, by more than a factor 3 at 0.2 mm. Figure 3 illustrates these effects.Optimal vibration reduces D by improving the growth conditions (reduction of temperature gradients by mixing, more uniform impurity distribution).     

A new standing-wave-type linear ultrasonic motor based on in-plane modes

This paper presents a new standing-wave-type linear ultrasonic motor using combination of the first longitudinal and the second bending modes. Two piezoelectric plates in combination with a metal thin plate are used to construct the stator. The superior point of the stator is its isosceles triangular structure part of the stator, which can amplify the displacement in horizontal direction of the stator in perpendicular direction when the stator is operated in the first longitudinal mode. The influence of the base angle θ of the triangular structure part on the amplitude of the driving foot has been analyzed by numerical analysis. Four prototype stators with different angles θ have been fabricated and the experimental investigation of these stators has validated the numerical simulation. The overall dimensions of the prototype stators are no more than 40 mm (length) × 20 mm (width) × 5 mm (thickness). Driven by an AC signal with the driving frequency of 53.3 kHz, the no-load speed and the maximal thrust of the prototype motor using the stator with base angle 20° were 98 mm/s and 3.2 N, respectively. The effective elliptical motion trajectory of the contact point of the stator can be achieved by the isosceles triangular structure part using only two PZTs, and thus it makes the motor low cost in fabrication, simple in structure and easy to realize miniaturization.