Review of Scientific Instruments最新文献

{"title":"Measuring the thermal conductivity of hydrogels with a bidirectional 3ω method.","authors":"Daniel H Hsieh, Youngmun Lee, Mayur S Prabhudesai, Jay Taylor, Paul V Braun, Sanjiv Sinha","doi":"10.1063/5.0245268","DOIUrl":"https://doi.org/10.1063/5.0245268","url":null,"abstract":"<p><p>Hydrogels are soft, water-absorbing polymer materials with diverse applications in biomedicine and agriculture. Recently, hydrogels have been proposed to encapsulate water-soluble phase change materials that store energy in their latent heat of solidification. In these applications, the thermal conductivity of these materials affects their performance. Few methods exist for measuring the thermal conductivity of small quantities of hydrogels. Here, we describe an implementation of the bidirectional 3ω technique to measure the thermal conductivity of hydrogels with particular attention to their moisture content. Our implementation of the technique can probe sample volumes as little as ∼20 μl and yields the thermal conductivity without requiring fitting of additional thermal parameters. We numerically simulate 3ω sensor designs with frequency-domain 3-D models to quantify and reduce errors introduced by the choice of substrate and insulation layer thickness. Frequencies in the ∼1-20 Hz range yield less error for the materials considered here. We verify our setup with measurements on water and report values for polyacrylamide and poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) hydrogels. Our swollen hydrogels exhibited thermal conductivities nearly equivalent to water, 0.6 W m-1 K-1, and we estimate thermal conductivities of 0.43 and 0.42 W m-1 K-1 for neat polyacrylamide and PAMPS, respectively. Finally, we estimate an error of ±7%, consistent with other 3ω methods, with the largest error coming from the sensor calibration. We find that our implementation of the bidirectional 3ω method gives reasonable results and can be employed for prototyping soft materials relevant to thermal storage.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143981052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling the differential susceptibility by Lorentzians.","authors":"Alexej Perevertov","doi":"10.1063/5.0252515","DOIUrl":"https://doi.org/10.1063/5.0252515","url":null,"abstract":"<p><p>The idea of extracting information on magnetically different phases from magnetic measurements is very attractive, and many efforts have been made in this area. One of the most popular directions is to use the Preisach model formalism to analyze the 2D Preisach distribution function (PDF) obtained either from first order reversal curves or minor loops. Here, we present an alternative, a much simpler procedure-the analysis of the derivative of the saturation magnetization loop, the differential susceptibility curve. It follows the Lorentzian shape with very high accuracy for ferromagnetic polycrystalline materials. This allows decomposing any differential susceptibility curve of a complex multi-phase material into individual components representing different magnetic phases by Lorentzian peaks-in the same way as it is done in x-ray diffraction analysis of materials. We show that the minor differential susceptibility curves also have the Lorentzian shape that can facilitate the calculation of the Preisach distribution function from the experimental curves and reduce noise in the resulting PDF.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144018611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A two-dimensional imaging enabled x-ray streak camera system.","authors":"Haochen Gu, Xu Zhao, Shan Wei, Peng Zhou, Qiang Zhou, Xiangyan Xu, Xiaohui Yuan, Zhe Zhang, Yutong Li, Jie Zhang","doi":"10.1063/5.0260920","DOIUrl":"https://doi.org/10.1063/5.0260920","url":null,"abstract":"<p><p>Streak cameras are powerful tools that provide high temporal resolution by capturing one-dimensional images with slitted photocathodes while sacrificing the two-dimensional spatial information. A two-dimensional imaging enabled x-ray streak camera system has been developed to acquire the two-dimensional images in situ, with 27 μm spatial resolution and 150 ps time resolution. By attaching a scintillator plate in front of the cathode, x-ray emissions beyond the cathode slit are converted into visible light and recorded by an imaging camera. The simultaneous measurement of one-dimensional time-resolved and two-dimensional time-integrated images in the laser fusion experiment has demonstrated the benefits of the endoscope. Such a system could greatly extend the uses of traditional x-ray streak cameras.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144041998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-temperature UHV scanning tunneling microscope double sample holder for in situ exchangeable clean room processed samples.","authors":"Umamahesh Thupakula, We-Hyo Soe, Jimmy Faria, Piyush Kanti Sarkar, A Omura Okano, Makoto Sakurai, Christian Joachim","doi":"10.1063/5.0228294","DOIUrl":"https://doi.org/10.1063/5.0228294","url":null,"abstract":"<p><p>A generalization of the double sample holder (DSH) concept is presented for an ultra-high vacuum (UHV) low-temperature (LT) multi-probe scanning tunneling microscope (STM). In UHV, the DSH is carrying, side-by-side, a reference metal sample [Au(111) single crystal for STM tip apex preparation] and an ancillary stand-alone small sample holder (for samples originating from a clean room) that can be mounted in situ in/out of the DSH plate. STM tip navigation on both sample surfaces is performed using a UHV scanning electron microscope positioned above the STM stage. For demonstration, clean room nanofabricated graphene nano-gears (diameter down to 25 nm) on a sapphire sample are characterized using STM. The STM tip apices are cleaned on the atomically precise and UHV cleaned Au(111) reference sample surface. Using our new DSH plate and in situ STM tip apex re-preparation on the reference metallic sample, we demonstrate how a clean room originating sample can be imaged at the atomic resolution using our LT-UHV 4-STM.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143754393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle displacement refinement based on hybrid cross-correlation optical flow method with gradient constancy assumption.","authors":"Hu Li, Guanyu Yan, Haidong Zhu, Yan Feng, Jingjing He","doi":"10.1063/5.0238355","DOIUrl":"https://doi.org/10.1063/5.0238355","url":null,"abstract":"<p><p>In particle image velocimetry (PIV), the brightness of a particle image sequence may change due to uneven laser intensity distribution and fluctuations in laser output. Consequently, the optical flow method (OFM), which relies on the brightness constancy assumption, becomes unsuitable. The traditional variational OFM is only accurate for small displacement fields but lacks robustness and accuracy when applied to PIV images with intensity variations. In this study, to address these issues, we improve the traditional cross-correlation OFM to establish a high-resolution hybrid cross-correlation optical flow method (CC-OFM) for particle images with large displacement and intensity variations. The data term, which combines the brightness constancy assumption with the gradient constancy assumption, compensates for the intensity changes between the particle image pairs. The proposed CC-OFM is quantitatively evaluated using both synthetic particle images and experimental particle images under various conditions, comparing the displacement results with those obtained using other methods. The results reveal that the proposed CC-OFM provides high accuracy and robustness for particle images with large displacement and intensity variations. Furthermore, its high spatial resolution allows it to capture flow details more effectively than the other methods.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143754414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BIFROST-An indirect geometry cold neutron spectrometer at the European Spallation Source.","authors":"Rasmus Toft-Petersen, Gregory S Tucker, Liam Whitelegg, Kristine Marie Løfgren Krighaar, Tamires Gallo, Marton Marko, Rodion Kolevatov, Sylvain Rodrigues, Finn Saxild, Keld Theodor, Jonas Okkels Birk, Martin A Olsen, Mads Bertelsen, Sonja Holm-Dahlin, Jakob Lass, Nicolai Lindaa Amin, Joakim Hoff-Møller, Ida Skøt Støvring, Peter Kjær Willendrup, Esben Klinkby, Amalia Chambon, Paola Caterina Forino, Efthymios Polatidis, Jan Capek, Jochen Stahn, Uwe Filges, Paolo Mutti, Martin Platz, Isabel Llamas Jansa, Bent Lauritzen, Henrik M Rønnow, Bjørn C Hauback, Philippe Bourges, Daniel G Mazzone, Christof Niedermayer, Kim Lefmann, Niels Bech Christensen","doi":"10.1063/5.0258847","DOIUrl":"https://doi.org/10.1063/5.0258847","url":null,"abstract":"<p><p>We present the detailed design and performance simulations of BIFROST, a multiplexing indirect neutron time-of-flight spectrometer at the European Spallation Source. The instrument allows a neutron bandwidth of Δλ = 1.74 Å to reach the sample. The polychromatic flux can reach 6 × 109 n/s/cm2 while retaining a relative energy resolution, δEi/Ei, of around 3.5% at Ei = 5 meV. A fast pulse-shaping chopper allows for flexibility in the primary spectrometer resolution. For an opening time of 0.1 ms, a relative energy resolution down to 0.2% is achieved for Ei = 12 meV. The secondary spectrometer consists of 45 analyzer arrays, populating 9 scattering angle channels in the horizontal scattering plane, each of which covers 5.2° in scattering angle. Each channel hosts 5 analyzer arrays reflecting neutrons of fixed energies Ef equal to 2.7, 3.2, 3.8, 4.4, and 5.0 meV. Utilizing the prismatic analyzer concept, the back-end geometry allows a secondary spectrometer energy resolution in the range of 0.02-0.05 meV. The unique design of BIFROST offers not only an unprecedented neutron flux but also the ability to adjust the energy resolution by more than one order of magnitude. Focusing on the horizontal scattering plane, the spectrometer is ideally suited for extreme environment studies and for studying samples much smaller than 1 cm3. The drastic increase in measurement efficiency, compared to current high-flux spectrometers, has a particularly high impact on the fields of quantum magnetism, unconventional superconductivity, and functional materials.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143981037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micro-cavity length stabilization for fluorescence enhancement using schemes based on higher-order spatial modes.","authors":"Abdullah Shehata Abdelatief, Antonius J Renders, Mohammed K Alqedra, Jannek J Hansen, David Hunger, Lars Rippe, Andreas Walther","doi":"10.1063/5.0251115","DOIUrl":"https://doi.org/10.1063/5.0251115","url":null,"abstract":"<p><p>We report on the experimental investigation of potential high-performance cavity length stabilization using odd-indexed higher-order spatial modes. Schemes based on higher-order modes are particularly useful for micro-cavities that are used for enhanced fluorescence detection of a few emitters, which need to minimize photons leaking from a stabilization beam. We describe the design and construction of an assembly for a microcavity setup with tunable high passive stability. In addition, different types of active stabilization techniques based on higher-order modes are then implemented and characterized based on their performance. We achieved a stability of about 0.5 pm rms, while the error photons leaking from the continuous locking beam to a fluorescence detector are suppressed by more than 100-fold. We expect these results to be important for quantum technology implementations of various emitter-cavity setups, where these techniques provide a useful tool to meet the highly challenging demands.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144029160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New generation bunch shape monitor for ion accelerators.","authors":"A C Araujo Martinez, R Agustsson, A Aleksandrov, S V Kutsaev, A Moro","doi":"10.1063/5.0253865","DOIUrl":"https://doi.org/10.1063/5.0253865","url":null,"abstract":"<p><p>Measuring longitudinal beam parameters is important for operation and development of high intensity linear accelerators, but it is notoriously difficult for proton and ion beams at non-relativistic energies. The Bunch Shape Monitor (BSM) is a device used for measuring the longitudinal bunch distribution in ion linacs. The existing BSM models have poor electron collection efficiency from the wire and are limited to one-dimensional measurements of the phase coordinate. In response to this problem, we have developed a new generation BSM with improved performance. The proposed design incorporates three major innovations: First, the collection efficiency was improved by adding a focusing field between the wire and the entrance slit, which will also allow measurements over a much wider dynamic range. Second, an improvement in the measurement speed was achieved by sampling longitudinal profiles of multiple energy slices simultaneously, where the BSM wire is placed at the exit of an ion spectrometer so that ions with different energies hit the wire at different horizontal coordinates along the wire. Finally, the design incorporates a motion system that can shift the wire and deflecting cavity together, enabling transverse profile measurements like a wire scanner. In this paper, we will provide the design of the new BSM and report on its beam test results at the Spallation Neutron Source facility in Oak Ridge National Laboratory.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144045325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Room temperature buffer gas beam of metastable state titanium atoms.","authors":"Jackson Schrott, Scott Eustice, Dan M Stamper-Kurn","doi":"10.1063/5.0243223","DOIUrl":"https://doi.org/10.1063/5.0243223","url":null,"abstract":"<p><p>We produce beams of neutral titanium (Ti) atoms in their metastable 3d3(F4)4sa5F5 state by laser ablation into He, N2, and Ar buffer gases. The high temperatures associated with the ablation process populate the a5F5 level without the need for optical pumping. Remarkably, we observe that Ti atoms in the a5F5 state survive thousands of collisions with He and Ar buffer gas atoms without being quenched to lower-energy states. We study the yield of Ti atoms when ablated into buffer gases of varying species and pressure, quantify quenching rates and diffusion cross sections based on simple models, and provide insight into optimal design parameters for an ablation cell. Using a 3.3 cm ablation cell with interchangeable exit apertures, we produce metastable atom beams and quantify their brilliance and velocity distributions as functions of buffer gas pressure.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144042802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential pumping for kHz operation of a laser wakefield accelerator based on a continuously flowing hydrogen gas jet.","authors":"J Monzac, S Smartsev, J Huijts, L Rovige, I A Andriyash, A Vernier, V Tomkus, V Girdauskas, G Raciukaitis, M Mackevičiūtė, V Stankevic, A Cavagna, J Kaur, A Kalouguine, R Lopez-Martens, J Faure","doi":"10.1063/5.0246912","DOIUrl":"https://doi.org/10.1063/5.0246912","url":null,"abstract":"<p><p>Laser-Wakefield Accelerators (LWFAs) running at kHz repetition rates hold great potential for applications. They typically operate with low-energy, highly compressed laser pulses focused on high-pressure gas targets. Experiments have shown that the best-quality electron beams are achieved using hydrogen gas targets. However, continuous operation with hydrogen requires a dedicated pumping system. In this work, we present a method for designing a differential pumping system, which we successfully implemented in our experiments. This enabled the first demonstration of continuous operation of a kHz LWFA using a high-pressure hydrogen gas jet. The system effectively maintained a pressure below 3 × 10-4 mbar, even with a free-flowing gas jet operating at 140 bar backing pressure. Numerical fluid dynamics and optical simulations were used to guide and validate the system's design.</p>","PeriodicalId":21111,"journal":{"name":"Review of Scientific Instruments","volume":"96 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143754367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}