Review of Scientific Instruments最新文献

Most portable gas chromatographs (GCs) were designed exclusively for gas samples. If they can handle liquid samples too, the range of application is expected to expand substantially. However, in general, the injection volume of liquid samples in GCs is limited to about 1 μl or less to prevent the loss of analytical precision and instrument contamination. Therefore, it is difficult to achieve sufficient sensitivity with the limited resources of the portable GCs. In this study, we developed a large volume injection (LVI) technique applicable to portable GCs, fabricated a compact LVI-GC using a spherical surface acoustic wave (SAW) sensor (the ball SAW sensor) as the detector, and confirmed its basic operation. Using a sample mixture of linear alkanes with 7-13 carbons in a pentane solvent, we evaluated measurement conditions without the loss of analyte in a sample volume range of ∼5-50 μl and confirmed the linearity of the response with respect to the sample volume. In addition, 1,2-methylenedioxybenzene, a simulant of a hallucinogen, 3,4-methylenedioxymethamphetamine (MDMA), was analyzed for an application in drug analysis in urine, and a detection limit of ∼23 ng/ml, well below the cutoff value of ∼250 ng/ml for MDMA, was achieved. Furthermore, we found a correlation between the response of the ball SAW sensor and the retention index and investigated the possibility of quantitative analysis using retention indices.

Acceleration measurement plays a significant role in various fields, such as resource exploration, national defense and military affairs, safety production, and disaster prevention and mitigation. In response to the current problems of low sensitivity and poor lateral anti-interference ability of optical fiber acceleration sensors, a Michelson interference type optical fiber acceleration sensor based on push-pull structure is proposed. First, a push-pull structure sensor model is established and its theoretical analysis is conducted; second, the sensor is analyzed for static stress and modal analysis using the ANSYS Workbench; and finally, the sensor prototype is fabricated and a sensing system is built, and its performance is tested through a vibration testing system. The results show that the sensor's natural frequency is 72 Hz, the sensitivity is 51.58 dB (re: 0 dB = 1 rad/g), the linearity is 99.68%, and the lateral anti-interference degree reaches 221 227.74 dB (re: 0 dB = 1 rad/g). Compared with existing similar sensors, its lateral interference resistance has increased by ∼10.8% and its sensitivity has been significantly enhanced. The research results provide a reference for the development of Michelson interference type optical fiber acceleration sensors.

The study of quantum vortex dynamics in He II offers great potential for advancing quantum-fluid models. Bose-Einstein condensates, neutron stars, and even superconductors exhibit quantum vortices, whose interactions are crucial for dissipation in these systems. These vortices have quantized velocity circulation around their cores, which, in He II, are of atomic size. They have been observed indirectly, through methods such as second sound attenuation or electron bubble imprints on photosensitive materials. Over the past twenty years, decorating cryogenic flows with particles has become a powerful approach to studying these vortices. However, recent particle visualization experiments often face challenges with stability, initial conditions, stationarity, and reproducibility. Moreover, most dynamical analyses are performed in 2D, even though many flows are inherently 3D. We constructed a rotating cryostat with optical ports on an elongated square cupola to enable 2D and 3D Lagrangian and Eulerian studies of rotating He II flow. Using this setup, individual quantum vortices have been tracked with micron-sized particles, as demonstrated by Peretti et al. [Sci. Adv. 9, eadh2899 (2023)]. The cryostat and associated equipment-laser, cameras, sensors, and electronics-float on a 50 μm air cushion, allowing for precise control of the experiment's physical parameters. The performance during rotation is discussed, along with details on particle injection.

We used a microcontroller-based setup for the data acquisition in a down-conversion experiment to detect single photon events. This type of setup allows us to compare the effect of the detector's dead time as well as the delay in the data acquisition on the measured data. By using various time windows for the single-photon data acquisition, we estimate the magnitude of the errors in the measuring process as a function of the correlation between the electronics delay and the detector's dead time. Our conclusions are validated by analyzing the particle number, detection rates, and statistical distributions, as well as the correlations between signal and idler photons.

As the electromagnetic environment becomes increasingly complex, the measurement of electric field intensity, a crucial parameter, is essential. An electric field probe is designed to fulfill this function. In this paper, the development of an electric field probe is presented, with a frequency range of 10 kHz-400 MHz. The probe comprises four components: a monopole antenna, an impedance conversion module, an amplifier, and a detection module. The probe utilizes DC voltage to indicate the field intensity. Following calibration in a TEM cell, the error of the probe is less than 6 dB. With the use of shielding, the probe's sensitivity reaches 90 dB (μV/m), and the maximum detectable field intensity is 140 dB (μV/m).

ZT (thermoelectric figure of merit) is the most direct parameter for the evaluation of the thermoelectric conversion efficiency of materials. At present, the ZT of micro/nanomaterials is often calculated by characterizing thermal and electrical properties separately in different samples, which may cause error propagation or incorrect results. This study used an in situ integrated measurement method for micro/nanomaterials, which can directly measure the ZT and simultaneously obtain their thermal conductivity, electrical conductivity, and Seebeck coefficient at once. The measurements of monolayers MoS2 show a significant coupling of the thermoelectric properties with the structure and temperature. Both samples showed a larger ZT on the narrow edge due to the low thermal conductivity and large Seebeck coefficient. At 474 K, the maximum ZT value of ∼0.02 obtained by combining the thermal and electrical parameters of the same sample showed a significant discrepancy of 1.95 times compared to the in situ characterization result of 0.009. The maximum and minimum ZT values (∼0.050 and ∼0.004) obtained from the combined calculation of the two samples differ even more significantly, amounting to 13.15 times. This study further validates the necessity of in situ characterization for micro/nanomaterials and provides a data reference for the application of MoS2 in the thermoelectric field.

Pohang Accelerator Laboratory (PAL) constructed a novel extreme ultraviolet (EUV) radiation generation synchrotron facility. We call this facility the Extreme Ultraviolet Synchrotron of the Pohang Accelerator Laboratory (PAL-EUV). The PAL-EUV facility consists of a linear accelerator, a booster synchrotron, and a storage ring synchrotron. Due to spatial constraints, these devices were installed very densely. For this reason, it is important to design the transport section from the linear accelerator to the booster synchrotron to be compact and efficient. Under this condition, we designed the electron beam transport section such that the dispersion of the electron beam is zero as it passes through the horizontal and vertical bending magnets. We installed diagnostic devices, including beam position monitors, screen monitors, a dark current monitor, and an electron beam spectrometer. We conducted commissioning using these devices. In this paper, we provide a detailed description of the structure and devices of the PAL-EUV linear accelerator and present the commissioning procedures and results.

A scalable control architecture for superconducting quantum processors is essential as the number of qubits increases and coherent multi-qubit operations span beyond the capacity of a single control module. The Quantum Instrumentation Control Kit (QICK), built on AMD RFSoC platforms, offers a flexible open-source framework for pulse-level qubit control but lacks native support for multi-board synchronization, limiting its applicability to mid- and large-scale quantum devices. To overcome this limitation, we introduce Manarat, a scalable multi-board control platform based on QICK that incorporates hardware, firmware, and software enhancements to enable sub-100 ps timing alignment across multiple AMD ZCU216 RFSoC boards. Our system integrates a low-jitter clock distribution network, modifications to the tProcessor, and a synchronization scheme to ensure deterministic alignment of program execution across boards. It also includes a custom analog front-end for flux control that combines high-speed RF signals with software-programmable DC biasing voltages generated by a low-noise, high-precision DAC. These capabilities are complemented by a software stack capable of orchestrating synchronized multi-board experiments and fully integrated with the open-source Qibo framework for quantum device calibration and algorithm execution. We validate Manarat on a 10-qubit superconducting processor controlled by two RFSoC boards, demonstrating reliable execution of synchronized control sequences for cross-board CZ gate calibration. These results confirm that sub-nanosecond synchronization and coherent control are achievable across multiple RFSoC boards, enabling scalable operation of superconducting quantum computers.

Thermal deformation of x-ray optical elements, especially the first element exposed to high thermal loads, can significantly degrade the performance of synchrotron radiation beamlines. Accurate wavefront measurement is essential for estimating such deformations and improving optical design. Talbot interferometry, employing phase and absorption gratings to produce moiré fringes, enables wide-field wavefront sensing across areas of several to tens of millimeters. However, mismatches in the designed period ratio between the gratings introduce systematic errors in wavefront curvature estimation and surface profile reconstruction. This study investigates the impact of such period mismatches on wavefront accuracy and presents a practical calibration method. Experiments with both minimally used and long-term exposed gratings show that calibration markedly improves the precision of surface profile measurements, reducing variation by up to 50%. These results emphasize the importance of precise grating period calibration for reliable wavefront and surface figure evaluation, particularly for optics subject to thermal deformation under high-power x-ray irradiation.

A new L-shaped molecular beam Fourier transform microwave spectrometer (L-FTMW) has been developed at Tennessee Tech University to perform both cavity and chirped-pulse rotational spectroscopy within a single platform. The instrument features an L-shaped high-vacuum chamber comprised of stainless-steel and polycarbonate sections, allowing orthogonal operation of Fabry-Perot cavity and chirped-pulse configurations without mechanical reconfiguration. This paper focuses on the design, operation, and performance of the 8-18 GHz Fabry-Perot cavity subsystem within the L-FTMW spectrometer. The cavity is formed by two 7.5-inch-diameter aluminum mirrors with 30 cm radii of curvature, arranged near-confocally and coupled to a near-coaxial pulsed molecular beam. A custom Python-based interface enables automated high-resolution mapping of cavity resonances and broadband data acquisition with minimal user intervention. The system routinely achieves 2 kHz frequency resolution, enabling precise measurement of hyperfine spectral features. Performance was validated through measurements of benchmark systems, including OCS isotopologues and their weakly bound van der Waals complexes. The 17O13CS isotopologue (natural abundance = 0.000 397 2%, corresponding to ∼40 ppb in a 1% OCS/argon mixture) was detected within 5 min of signal averaging at natural abundance with argon as the carrier gas. The simple mechanical design and open-source control software make the L-FTMW spectrometer a versatile and accessible platform for high-resolution rotational spectroscopy and future investigations of reaction dynamics and kinetics.