F. Grussie, A. O'Connor, M. Grieser, D. Müll, A. Znotins, X. Urbain, H. Kreckel
We describe a merged beams experiment to study ion-neutral collisions at the Cryogenic Storage Ring of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We produce fast beams of neutral atoms in their ground term at kinetic energies between 10 and 300 keV by laser photodetachment of negative ions. The neutral atoms are injected along one of the straight sections of the storage ring, where they can react with stored molecular ions. Several dedicated detectors have been installed to detect charged reaction products of various product-to-reactant mass ranges. The relative collision energy can be tuned by changing the kinetic energy of the neutral beam in an independent drift tube. We give a detailed description of the setup and its capabilities, and present proof-of-principle measurements on the reaction of neutral C atoms with D2 + ions.
{"title":"An ion-atom merged beams setup at the Cryogenic Storage Ring.","authors":"F. Grussie, A. O'Connor, M. Grieser, D. Müll, A. Znotins, X. Urbain, H. Kreckel","doi":"10.1063/5.0086391","DOIUrl":"https://doi.org/10.1063/5.0086391","url":null,"abstract":"We describe a merged beams experiment to study ion-neutral collisions at the Cryogenic Storage Ring of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We produce fast beams of neutral atoms in their ground term at kinetic energies between 10 and 300 keV by laser photodetachment of negative ions. The neutral atoms are injected along one of the straight sections of the storage ring, where they can react with stored molecular ions. Several dedicated detectors have been installed to detect charged reaction products of various product-to-reactant mass ranges. The relative collision energy can be tuned by changing the kinetic energy of the neutral beam in an independent drift tube. We give a detailed description of the setup and its capabilities, and present proof-of-principle measurements on the reaction of neutral C atoms with D2 + ions.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"136 1","pages":"053305"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77448790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Martin, H. Ahmed, D. Doria, A. Alejo, R. Clarke, S. Ferguson, J. Fernández-Tobias, R. Freeman, J. Fuchs, A. Green, J. Green, D. Gwynne, F. Hanton, J. Jarrett, D. Jung, K. Kakolee, A. Krygier, C. Lewis, A. McIlvenny, P. McKenna, J. Morrison, Z. Najmudin, K. Naughton, G. Nersisyan, P. Norreys, M. Notley, M. Roth, J. A. Ruiz, C. Scullion, M. Zepf, S. Zhai, M. Borghesi, S. Kar
Image plates (IPs) are a popular detector in the field of laser driven ion acceleration, owing to their high dynamic range and reusability. An absolute calibration of these detectors to laser-driven protons in the routinely produced tens of MeV energy range is, therefore, essential. In this paper, the response of Fujifilm BAS-TR IPs to 1-40 MeV protons is calibrated by employing the detectors in high resolution Thomson parabola spectrometers in conjunction with a CR-39 nuclear track detector to determine absolute proton numbers. While CR-39 was placed in front of the image plate for lower energy protons, it was placed behind the image plate for energies above 10 MeV using suitable metal filters sandwiched between the image plate and CR-39 to select specific energies. The measured response agrees well with previously reported calibrations as well as standard models of IP response, providing, for the first time, an absolute calibration over a large range of proton energies of relevance to current experiments.
{"title":"Absolute calibration of Fujifilm BAS-TR image plate response to laser driven protons up to 40 MeV.","authors":"P. Martin, H. Ahmed, D. Doria, A. Alejo, R. Clarke, S. Ferguson, J. Fernández-Tobias, R. Freeman, J. Fuchs, A. Green, J. Green, D. Gwynne, F. Hanton, J. Jarrett, D. Jung, K. Kakolee, A. Krygier, C. Lewis, A. McIlvenny, P. McKenna, J. Morrison, Z. Najmudin, K. Naughton, G. Nersisyan, P. Norreys, M. Notley, M. Roth, J. A. Ruiz, C. Scullion, M. Zepf, S. Zhai, M. Borghesi, S. Kar","doi":"10.1063/5.0089402","DOIUrl":"https://doi.org/10.1063/5.0089402","url":null,"abstract":"Image plates (IPs) are a popular detector in the field of laser driven ion acceleration, owing to their high dynamic range and reusability. An absolute calibration of these detectors to laser-driven protons in the routinely produced tens of MeV energy range is, therefore, essential. In this paper, the response of Fujifilm BAS-TR IPs to 1-40 MeV protons is calibrated by employing the detectors in high resolution Thomson parabola spectrometers in conjunction with a CR-39 nuclear track detector to determine absolute proton numbers. While CR-39 was placed in front of the image plate for lower energy protons, it was placed behind the image plate for energies above 10 MeV using suitable metal filters sandwiched between the image plate and CR-39 to select specific energies. The measured response agrees well with previously reported calibrations as well as standard models of IP response, providing, for the first time, an absolute calibration over a large range of proton energies of relevance to current experiments.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"1 1","pages":"053303"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85102727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Feng Zhou, Fan Zhu, Qiang Lyu, Xingzhen Bai, Baochun Cui, Pengfei Wang
Due to the difficulty in accurately detecting the health status of cable joints, a new method of identifying and assessing the cable joints' health status based on traveling wave reflection is proposed. By transmitting nanosecond pulse signals at the head end of the cable, the health status characteristics of the cable joints can be obtained, and the noise reduction of the measurement signals is performed by the wavelet function to identify the reflected wave at the joint and the end of the cable. The equivalent circuits and simulation models of contact resistance and leakage resistance are established, and the contact resistance and leakage resistance of the cable joints are calculated according to the amplitude and phase of the reflected signals at the joint and the end of the cable. By comparing with the resistance when the joint is in healthy operation, any measured parameter exceeding the corresponding standard is considered a joint fault. Simulations and test results show that the method can accurately identify the reflected signals of the cable joints in different operating states, and with changes in joint health, clear regular features can be extracted from the reflected signals, and the quality and health of the joints can be determined. The traveling wave method can be used to detect cable joint faults and provide an early warning of defects, which provides a new idea for online monitoring and early warning of cable joints in both theory and engineering practice.
{"title":"Identification and assessment method of cable joint health status based on traveling wave reflection.","authors":"Feng Zhou, Fan Zhu, Qiang Lyu, Xingzhen Bai, Baochun Cui, Pengfei Wang","doi":"10.1063/5.0085007","DOIUrl":"https://doi.org/10.1063/5.0085007","url":null,"abstract":"Due to the difficulty in accurately detecting the health status of cable joints, a new method of identifying and assessing the cable joints' health status based on traveling wave reflection is proposed. By transmitting nanosecond pulse signals at the head end of the cable, the health status characteristics of the cable joints can be obtained, and the noise reduction of the measurement signals is performed by the wavelet function to identify the reflected wave at the joint and the end of the cable. The equivalent circuits and simulation models of contact resistance and leakage resistance are established, and the contact resistance and leakage resistance of the cable joints are calculated according to the amplitude and phase of the reflected signals at the joint and the end of the cable. By comparing with the resistance when the joint is in healthy operation, any measured parameter exceeding the corresponding standard is considered a joint fault. Simulations and test results show that the method can accurately identify the reflected signals of the cable joints in different operating states, and with changes in joint health, clear regular features can be extracted from the reflected signals, and the quality and health of the joints can be determined. The traveling wave method can be used to detect cable joint faults and provide an early warning of defects, which provides a new idea for online monitoring and early warning of cable joints in both theory and engineering practice.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"20 1","pages":"054703"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85282941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, the pulse forming technology based on metal oxide varistors (MOVs) has been verified to be an effective way to generate high-voltage quasi-square pulses. Due to the limited varistor voltage of a single MOV brick, multiple MOV bricks connected in series are required to stabilize a pulse with high amplitude (larger than hundreds of kV), which leads to the rise of the series inductance of the MOV branch and the flat-top droop in the output waveform. This paper provides two solutions to reduce the influence of the MOV branch inductance on output waveforms. One is that a coaxial evolute structure of the MOV bricks connected in series is designed, which can not only improve the insulation capacity but also reduce the branch inductance. Another is that a flat-top compensation scheme named "PFN-MOV" (Pulse Forming Network) is proposed, which adds an LC filtering branch to shape the signal into a flat-top rising wave with ripple and then offsets the flat-top droop caused by the inductance of the MOV branch. Based on the above ideas, a high-voltage, long-pulse width, flat-top compensation pulse generator is designed and tested, and a quasi-square pulse with voltage amplitude of more than 500 kV, pulse width greater than 800 ns, rise time of less than 50 ns, and flat top of about 600 ns is obtained experimentally. This MOV based generator has the advantage of simple design, compact construction, and better flat top, which is promising to be used as a compact long-pulse driver in many fields, such as high-current accelerator, industrial dedusting, medical sterilization, and cancer treatment.
{"title":"The design of a high-voltage, long-pulse width, flat-top compensation pulse generator based on metal oxide varistors.","authors":"Hao Lu, Motao Zhang, Hanwu Yang, Huibo Zhang, Zicheng Zhang, Jingming Gao","doi":"10.1063/5.0071272","DOIUrl":"https://doi.org/10.1063/5.0071272","url":null,"abstract":"In recent years, the pulse forming technology based on metal oxide varistors (MOVs) has been verified to be an effective way to generate high-voltage quasi-square pulses. Due to the limited varistor voltage of a single MOV brick, multiple MOV bricks connected in series are required to stabilize a pulse with high amplitude (larger than hundreds of kV), which leads to the rise of the series inductance of the MOV branch and the flat-top droop in the output waveform. This paper provides two solutions to reduce the influence of the MOV branch inductance on output waveforms. One is that a coaxial evolute structure of the MOV bricks connected in series is designed, which can not only improve the insulation capacity but also reduce the branch inductance. Another is that a flat-top compensation scheme named \"PFN-MOV\" (Pulse Forming Network) is proposed, which adds an LC filtering branch to shape the signal into a flat-top rising wave with ripple and then offsets the flat-top droop caused by the inductance of the MOV branch. Based on the above ideas, a high-voltage, long-pulse width, flat-top compensation pulse generator is designed and tested, and a quasi-square pulse with voltage amplitude of more than 500 kV, pulse width greater than 800 ns, rise time of less than 50 ns, and flat top of about 600 ns is obtained experimentally. This MOV based generator has the advantage of simple design, compact construction, and better flat top, which is promising to be used as a compact long-pulse driver in many fields, such as high-current accelerator, industrial dedusting, medical sterilization, and cancer treatment.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"3 1","pages":"054704"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91099366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The heated metal needle used for tumor thermotherapy is considered crucial for enhancing the practicality of cauterization using electromagnetic induction-heating techniques. In this study, a novel coil capable of producing a deep magnetic field is designed. In the proposed design, the coil structure is improved to enhance the intensity of the coil's deep magnetic field and its suitability for deep-tissue cauterization. Furthermore, a series of experiments are conducted using a single and consistent input current. The heating experiments are conducted at varying depths by placing the needle beneath the coil. The proposed coil significantly increases the induction-heating temperature and provides a solution to the long-standing problem of insufficient needle temperature. This research has also improved the usability of the induction-heating equipment in the field of deep tumor ablation.
{"title":"Liver tumor ablation enhancement by induction-heating system with bitter-like deep magnetic field coil.","authors":"Chia-Ming Hung, C.C. Tai","doi":"10.1063/5.0066308","DOIUrl":"https://doi.org/10.1063/5.0066308","url":null,"abstract":"The heated metal needle used for tumor thermotherapy is considered crucial for enhancing the practicality of cauterization using electromagnetic induction-heating techniques. In this study, a novel coil capable of producing a deep magnetic field is designed. In the proposed design, the coil structure is improved to enhance the intensity of the coil's deep magnetic field and its suitability for deep-tissue cauterization. Furthermore, a series of experiments are conducted using a single and consistent input current. The heating experiments are conducted at varying depths by placing the needle beneath the coil. The proposed coil significantly increases the induction-heating temperature and provides a solution to the long-standing problem of insufficient needle temperature. This research has also improved the usability of the induction-heating equipment in the field of deep tumor ablation.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"63 1","pages":"054107"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85255474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A piezoelectric energy harvester with backpressure pre-loaded is designed to investigate the performance that can be driven by the compressed air load in the pneumatic system. The power generation principle and microelement mechanics model are established, which can explain the principle that backpressure changes the internal energy of materials. The backpressure affects the internal stress of materials. The electromechanical coupling coefficient can be adjusted by the backpressure. The power generation obviously changes as the electromechanical coupling coefficient is adjusted. An experimental testing system is established, and the experimental results are analyzed to prove the effect of backpressure on the output power. There is a linear relationship between the peak voltage and backpressure. When the backpressure increases every 1 kPa, the voltage increases by 0.667 V. The voltage increment under backpressure is 5.13 times that without backpressure. The optimal output power is 12.3 mW in 30 kPa backpressure pre-load. The output power increases to the original 237% under the backpressure. The prototype can directly supply energy to the temperature sensor, and it can supply power to a magnetic switch with capacitor energy storage.
{"title":"Investigation on behavior of the backpressure based piezoelectric energy harvester driven by compressed air.","authors":"Yingting Wang, Zi Wang, Gang Bao","doi":"10.1063/5.0086093","DOIUrl":"https://doi.org/10.1063/5.0086093","url":null,"abstract":"A piezoelectric energy harvester with backpressure pre-loaded is designed to investigate the performance that can be driven by the compressed air load in the pneumatic system. The power generation principle and microelement mechanics model are established, which can explain the principle that backpressure changes the internal energy of materials. The backpressure affects the internal stress of materials. The electromechanical coupling coefficient can be adjusted by the backpressure. The power generation obviously changes as the electromechanical coupling coefficient is adjusted. An experimental testing system is established, and the experimental results are analyzed to prove the effect of backpressure on the output power. There is a linear relationship between the peak voltage and backpressure. When the backpressure increases every 1 kPa, the voltage increases by 0.667 V. The voltage increment under backpressure is 5.13 times that without backpressure. The optimal output power is 12.3 mW in 30 kPa backpressure pre-load. The output power increases to the original 237% under the backpressure. The prototype can directly supply energy to the temperature sensor, and it can supply power to a magnetic switch with capacitor energy storage.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"14 1","pages":"055003"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90830191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For insulators, the accumulated charge on the surface after electron bombardment will interfere with the total electron emission yield (TEEY) measurement. This work develops a novel method to automatically measure the TEEY of insulators based on self-terminating charge neutralization using two neutralization electron guns. We perform theoretical analysis and experimental design for the neutralization of positive and negative charges. Positive charges are neutralized by an electron gun whose cathode is equipotential to the sample. Negative charges are neutralized by another electron gun whose cathode is adjusted to a negative potential with respect to the grounded sample, which is set between EP1/e and EP2/e. We test the control and stability performance of the TEEY measurement system based on the timing design of the electron gun switching and believe that it meets the TEEY measurement requirements. The TEEY measurements of glass, Si, and SiO2 are in good agreement with the data reported in the references, which validates the accuracy of our method in this work. We anticipate that our method provides an essential reference for the rapid TEEY measurements of insulators.
{"title":"Measurement of total electron emission yield of insulators based on self-terminating charge neutralization.","authors":"Yahui Cai, Dan Wang, Kangcheng Qi, Yong-ning He","doi":"10.1063/5.0080414","DOIUrl":"https://doi.org/10.1063/5.0080414","url":null,"abstract":"For insulators, the accumulated charge on the surface after electron bombardment will interfere with the total electron emission yield (TEEY) measurement. This work develops a novel method to automatically measure the TEEY of insulators based on self-terminating charge neutralization using two neutralization electron guns. We perform theoretical analysis and experimental design for the neutralization of positive and negative charges. Positive charges are neutralized by an electron gun whose cathode is equipotential to the sample. Negative charges are neutralized by another electron gun whose cathode is adjusted to a negative potential with respect to the grounded sample, which is set between EP1/e and EP2/e. We test the control and stability performance of the TEEY measurement system based on the timing design of the electron gun switching and believe that it meets the TEEY measurement requirements. The TEEY measurements of glass, Si, and SiO2 are in good agreement with the data reported in the references, which validates the accuracy of our method in this work. We anticipate that our method provides an essential reference for the rapid TEEY measurements of insulators.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"1 1","pages":"055103"},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86057399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shouxiao Li, Huaxiang Wang, Tonghai Liu, Z. Cui, Joanna N. Chen, Zihan Xia, Qi Guo
Electrical resistance tomography (ERT) is considered a novel sensing technique for monitoring conductivity distribution. Image reconstruction of ERT is an ill-posed inverse problem. In this paper, an improved regularization reconstruction method is presented to solve this issue. We adopted homotopic mapping to choose the regularization parameter of the iterative Tikhonov algorithm. The standard normal distribution function was used to continuously adjust the regularization parameter. Subsequently, the resultant image vector was deployed as the initial value of the iterative Tikhonov algorithm to improve the image quality. Finally, the improved method was combined with a projection algorithm based on the Krylov subspace, which was also effective in reducing the computational time. Both simulation and experimental results indicated that the new algorithm could improve the real-time performance and imaging quality.
{"title":"A fast Tikhonov regularization method based on homotopic mapping for electrical resistance tomography.","authors":"Shouxiao Li, Huaxiang Wang, Tonghai Liu, Z. Cui, Joanna N. Chen, Zihan Xia, Qi Guo","doi":"10.1063/5.0077483","DOIUrl":"https://doi.org/10.1063/5.0077483","url":null,"abstract":"Electrical resistance tomography (ERT) is considered a novel sensing technique for monitoring conductivity distribution. Image reconstruction of ERT is an ill-posed inverse problem. In this paper, an improved regularization reconstruction method is presented to solve this issue. We adopted homotopic mapping to choose the regularization parameter of the iterative Tikhonov algorithm. The standard normal distribution function was used to continuously adjust the regularization parameter. Subsequently, the resultant image vector was deployed as the initial value of the iterative Tikhonov algorithm to improve the image quality. Finally, the improved method was combined with a projection algorithm based on the Krylov subspace, which was also effective in reducing the computational time. Both simulation and experimental results indicated that the new algorithm could improve the real-time performance and imaging quality.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"148 1","pages":"043709"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75024797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An ultra-small angle light scattering setup with the ability of simultaneous registration of scattered light by a charge-coupled device camera and the transmitted direct beam by a pin photodiode was developed. A pinhole mirror was used to reflect the scattered light; the transmitted direct beam was focused and passed through the central pinhole with a diameter of 500 μm. Time-resolved static light scattering measurement was carried out over the angular range 0.2° ≤θ≤ 8.9° with a time resolution of ∼33 ms. The measured scattering pattern in the q-range between 5 × 10-5 and 1.5 × 10-3 nm-1 enables investigating structures of few micrometers to submillimeter, where q is the scattering vector. A LabVIEW-based graphical user interface was developed, which integrates the data acquisition of the scattering pattern and the transmitted intensity. The Peltier temperature-controlled sample cells of varying thicknesses allow for a rapid temperature equilibration and minimization of multiple scattering. The spinodal decomposition for coacervation (phase separation) kinetics of an aqueous mixture of oppositely charged polyelectrolytes was demonstrated.
{"title":"Pinhole mirror-based ultra-small angle light scattering setup for simultaneous measurement of scattering and transmission.","authors":"Samim Ali, Yimin Mao, V. Prabhu","doi":"10.1063/5.0086146","DOIUrl":"https://doi.org/10.1063/5.0086146","url":null,"abstract":"An ultra-small angle light scattering setup with the ability of simultaneous registration of scattered light by a charge-coupled device camera and the transmitted direct beam by a pin photodiode was developed. A pinhole mirror was used to reflect the scattered light; the transmitted direct beam was focused and passed through the central pinhole with a diameter of 500 μm. Time-resolved static light scattering measurement was carried out over the angular range 0.2° ≤θ≤ 8.9° with a time resolution of ∼33 ms. The measured scattering pattern in the q-range between 5 × 10-5 and 1.5 × 10-3 nm-1 enables investigating structures of few micrometers to submillimeter, where q is the scattering vector. A LabVIEW-based graphical user interface was developed, which integrates the data acquisition of the scattering pattern and the transmitted intensity. The Peltier temperature-controlled sample cells of varying thicknesses allow for a rapid temperature equilibration and minimization of multiple scattering. The spinodal decomposition for coacervation (phase separation) kinetics of an aqueous mixture of oppositely charged polyelectrolytes was demonstrated.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"16 1","pages":"044104"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81861170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bowen Wang, Xiang Peng, Haidong Wang, Yang Liu, Hong Guo
Differential single-beam saturated-absorption spectroscopy (DSSAS) is proposed to stabilize lasing frequency and suppress Doppler-broadened background and common-mode optical noise. The spectral first-derivative demodulated signal of metastable He4 atoms is used as an error signal to stabilize a fiber laser around 1083 nm. Experimental results show that, compared with existing non-DSSAS frequency stabilization, DSSAS stabilization produces better stability and lower fluctuations, especially for frequency-noise-corrupted lasers. In DSSAS stabilization, for data acquired over 7000 s, the root mean square frequency fluctuation of the fiber laser is 16.4 kHz, and the frequency stability described by the modified Allan deviation is 4.1 × 10-12 at 100 s. Even for a defective laser with poor frequency stability, the proposed scheme demonstrates experimentally high capability of noise suppression and reduces the frequency fluctuations by two orders of magnitude. Given its simplicity and compact design, frequency stabilization by DSSAS is promising for quantum-sensor applications, such as atomic magnetometers, atomic gyroscopes, and atomic clocks.
{"title":"Laser-frequency stabilization with differential single-beam saturated absorption spectroscopy of 4He atoms.","authors":"Bowen Wang, Xiang Peng, Haidong Wang, Yang Liu, Hong Guo","doi":"10.1063/5.0084605","DOIUrl":"https://doi.org/10.1063/5.0084605","url":null,"abstract":"Differential single-beam saturated-absorption spectroscopy (DSSAS) is proposed to stabilize lasing frequency and suppress Doppler-broadened background and common-mode optical noise. The spectral first-derivative demodulated signal of metastable He4 atoms is used as an error signal to stabilize a fiber laser around 1083 nm. Experimental results show that, compared with existing non-DSSAS frequency stabilization, DSSAS stabilization produces better stability and lower fluctuations, especially for frequency-noise-corrupted lasers. In DSSAS stabilization, for data acquired over 7000 s, the root mean square frequency fluctuation of the fiber laser is 16.4 kHz, and the frequency stability described by the modified Allan deviation is 4.1 × 10-12 at 100 s. Even for a defective laser with poor frequency stability, the proposed scheme demonstrates experimentally high capability of noise suppression and reduces the frequency fluctuations by two orders of magnitude. Given its simplicity and compact design, frequency stabilization by DSSAS is promising for quantum-sensor applications, such as atomic magnetometers, atomic gyroscopes, and atomic clocks.","PeriodicalId":54761,"journal":{"name":"Journal of the Optical Society of America and Review of Scientific Instruments","volume":"24 1","pages":"043001"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81136347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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