In this paper, “Brain MR Image Intensity in homogeneity estimation and Segmentation using Modified Local Intensity Clustering” is proposed. This method is applied on synthetic data taken from brain web simulated database which are taken at to 1.5T and three T MR of Simons MRI Scanner. The efficient, simultaneous intensity in homogeneity correction, noise reduction and tissue segmentation is obtained with this algorithm. A modified coherent local intensity clustering phenomenon along with chambolle’s fast twin emesis manner is applied on a dataset of 50 brain MR images. Parenthetically the overall effectively of powerful algorithm over other intensity in homogeneity and tissue segmentation algorithms. The proposed algorithm is compared with the unified segmentation methods, “FCM, Kernel FCM and Multiplicative Intrinsic Component Optimization (MICO)”, In terms of time response, the simulation results obtained are superior., Jaccard Similarity Index Measure and Dice similarity coefficient it is ended a utilize the qualified energy usable role model closet capable of achieve JSIM is 0.988 and DSC is 0.99.
{"title":"Performance and analysis of brain MRI segmentation in MATLAB","authors":"G. Devi","doi":"10.1063/5.0058053","DOIUrl":"https://doi.org/10.1063/5.0058053","url":null,"abstract":"In this paper, “Brain MR Image Intensity in homogeneity estimation and Segmentation using Modified Local Intensity Clustering” is proposed. This method is applied on synthetic data taken from brain web simulated database which are taken at to 1.5T and three T MR of Simons MRI Scanner. The efficient, simultaneous intensity in homogeneity correction, noise reduction and tissue segmentation is obtained with this algorithm. A modified coherent local intensity clustering phenomenon along with chambolle’s fast twin emesis manner is applied on a dataset of 50 brain MR images. Parenthetically the overall effectively of powerful algorithm over other intensity in homogeneity and tissue segmentation algorithms. The proposed algorithm is compared with the unified segmentation methods, “FCM, Kernel FCM and Multiplicative Intrinsic Component Optimization (MICO)”, In terms of time response, the simulation results obtained are superior., Jaccard Similarity Index Measure and Dice similarity coefficient it is ended a utilize the qualified energy usable role model closet capable of achieve JSIM is 0.988 and DSC is 0.99.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75409737","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}
H. Tyagi, K. Patel, R. Yadav, H. Mistri, A. Gahlaut, K. Pandya, M. Bhuyan, M. Singh, M. Bandyopadhyay, A. Chakraborty
Negative ion-based inductively coupled plasma sources operate in a high RF power and HV environment for plasma production and beam transport. Due to plasma power coupling dynamics, RF power mismatch causes large reflected fields which affect all the diagnostic signals, degrading the signal to noise ratio. In addition to RF disturbances, during the beam extraction and acceleration, the diagnostic signals are also prone to suffer during HV breakdowns due to high dV/dt fast switching of the HV system. The breakdowns cause the generation of HV transients which in turn disturb the entire signal referencing system. Such an operational environment poses challenges for front end electronics design for low voltage signals like the one from thermocouple sensors, which are some of the most important diagnostic elements in such sources. The surface-mounted thermocouples referenced to floating potential pick up noise from HV transients and RF noise. A signal conditioning system is therefore needed to arrest the noise sources and provide clean signals for the acquisition and control system. Such signal conditioning needs specific RF filters and PCB design. Special attention is also required for shielding and grounding to help reduce noise interference. The present work discusses the measurements in light of the improvements made to the front end electronics for the thermocouples used on the ROBIN RF-based negative ion source test bed. The source operates at 1 MHz RF and with HV power supplies rated at 11 kV 35 A for extraction and 35 kV 15 A for acceleration. Mismatch fields of the order of 90 V/m have been observed. The overall signal chain from field to presentation layer shall be presented with the measures undertaken to solve the noise interference.
{"title":"Noise mitigation techniques in thermocouple signals in negative ion sources with RF and HV transients","authors":"H. Tyagi, K. Patel, R. Yadav, H. Mistri, A. Gahlaut, K. Pandya, M. Bhuyan, M. Singh, M. Bandyopadhyay, A. Chakraborty","doi":"10.1063/5.0057714","DOIUrl":"https://doi.org/10.1063/5.0057714","url":null,"abstract":"Negative ion-based inductively coupled plasma sources operate in a high RF power and HV environment for plasma production and beam transport. Due to plasma power coupling dynamics, RF power mismatch causes large reflected fields which affect all the diagnostic signals, degrading the signal to noise ratio. In addition to RF disturbances, during the beam extraction and acceleration, the diagnostic signals are also prone to suffer during HV breakdowns due to high dV/dt fast switching of the HV system. The breakdowns cause the generation of HV transients which in turn disturb the entire signal referencing system. Such an operational environment poses challenges for front end electronics design for low voltage signals like the one from thermocouple sensors, which are some of the most important diagnostic elements in such sources. The surface-mounted thermocouples referenced to floating potential pick up noise from HV transients and RF noise. A signal conditioning system is therefore needed to arrest the noise sources and provide clean signals for the acquisition and control system. Such signal conditioning needs specific RF filters and PCB design. Special attention is also required for shielding and grounding to help reduce noise interference. The present work discusses the measurements in light of the improvements made to the front end electronics for the thermocouples used on the ROBIN RF-based negative ion source test bed. The source operates at 1 MHz RF and with HV power supplies rated at 11 kV 35 A for extraction and 35 kV 15 A for acceleration. Mismatch fields of the order of 90 V/m have been observed. The overall signal chain from field to presentation layer shall be presented with the measures undertaken to solve the noise interference.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73853231","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 conception of Ordinary Portland Cement (OPC) diffuses CO2 into the air. Fly ash, which is a result acquired from coal industry, and replacement of OPC utilized in the construction. It is rich in silicate gel with alkaline solution to produce great cement. Expansion in fly ash fineness progresses the compressive strength and reduces the porosity. This investigation aims to study the flexural behavior of geopolymer concrete of M 30 grade and compares the same with OPC beam and column, to obtain the required compressive strength, 15% of GGBS is added to fly ash used in GPC, six (4GPC+2OPC) reinforced concrete beams and columns of size 150mm × 150 mm × 1200 mm were tested and cured under ambient temperature. Geopolymer concrete was made from flyash and ggbs which are byproducts of steel and thermal industries. The outcomes show that there is a rise in flexural strength, service load and peak load of GPC beams and columns than OPC beams and columns.
{"title":"Flexural behavior of RC structural elements made by geopolymer concrete","authors":"S. Srinidhi, T. Srinivas","doi":"10.1063/5.0058496","DOIUrl":"https://doi.org/10.1063/5.0058496","url":null,"abstract":"The conception of Ordinary Portland Cement (OPC) diffuses CO2 into the air. Fly ash, which is a result acquired from coal industry, and replacement of OPC utilized in the construction. It is rich in silicate gel with alkaline solution to produce great cement. Expansion in fly ash fineness progresses the compressive strength and reduces the porosity. This investigation aims to study the flexural behavior of geopolymer concrete of M 30 grade and compares the same with OPC beam and column, to obtain the required compressive strength, 15% of GGBS is added to fly ash used in GPC, six (4GPC+2OPC) reinforced concrete beams and columns of size 150mm × 150 mm × 1200 mm were tested and cured under ambient temperature. Geopolymer concrete was made from flyash and ggbs which are byproducts of steel and thermal industries. The outcomes show that there is a rise in flexural strength, service load and peak load of GPC beams and columns than OPC beams and columns.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86545575","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}
O. Sotnikov, A. Sanin, Y. Belchenko, A. Ivanov, G. Abdrashitov, A. Belavsky, A. Gorbovsky, A. Donin, P. Deichuli, A. Dranichnikov, A. Kondakov, I. Shikhovtsev
A high-voltage negative ion based neutral beam injector is under construction at the Budker Institute of Nuclear Physics. It consists of a negative ion source, a Low Energy Beam Transport section (LEBT), which purifies the beam before acceleration, a multi-electrode single-aperture beam accelerator, a negative ion neutralizer and a magnetic separator with beam energy recuperators. The test stand to study the main injector components, consisting of the negative ion source and LEBT, the high voltage platform and the accelerator with beam transport section was launched in 2019. The initial experiments on the negative ion beam production, acceleration and 180 keV transport were tested. The power load to the acceleration tube electrodes and the data on the transported beam parameters, measured at the several positions and at the beam dump calorimeter are presented. The beam transport efficiency as a function of various ion source and LEBT parameters are presented and discussed.
{"title":"Negative ion beam acceleration and transport in the high voltage injector prototype","authors":"O. Sotnikov, A. Sanin, Y. Belchenko, A. Ivanov, G. Abdrashitov, A. Belavsky, A. Gorbovsky, A. Donin, P. Deichuli, A. Dranichnikov, A. Kondakov, I. Shikhovtsev","doi":"10.1063/5.0059022","DOIUrl":"https://doi.org/10.1063/5.0059022","url":null,"abstract":"A high-voltage negative ion based neutral beam injector is under construction at the Budker Institute of Nuclear Physics. It consists of a negative ion source, a Low Energy Beam Transport section (LEBT), which purifies the beam before acceleration, a multi-electrode single-aperture beam accelerator, a negative ion neutralizer and a magnetic separator with beam energy recuperators. The test stand to study the main injector components, consisting of the negative ion source and LEBT, the high voltage platform and the accelerator with beam transport section was launched in 2019. The initial experiments on the negative ion beam production, acceleration and 180 keV transport were tested. The power load to the acceleration tube electrodes and the data on the transported beam parameters, measured at the several positions and at the beam dump calorimeter are presented. The beam transport efficiency as a function of various ion source and LEBT parameters are presented and discussed.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87330191","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 Los Alamos Neutron Science Center (LANSCE) H− ion source (LHIS) has provided stable output for decades of LANL mission needs. While several in-house improvements have been made to its stability and lifetime, its maximum beam output has remained the same at ~14 mA. While operationally well understood, the internal relationship between the LHIS plasma, cesium distribution (the catalyst for producing H− ions), and produced H− beam remains a mystery, only explored indirectly with models. We will develop fast, accurate, and non-invasive diagnostics techniques to measure the Cs and H− densities inside LHIS. These diagnostics are based on optical absorption spectroscopy that have been developed in the last decade for fusion based H- ion sources that can readily be applied to the accelerator based LHIS. A refined form of optical absorption spectroscopy, the laser absorption technique (LAT), utilizes lasers tuned to a given atomic species to measure its density. In this case a laser tuned to the D2 line of cesium will be used to determine its density inside LHIS. Similarly, a refined version of LAT called the cavity ring-ring down spectroscopy (CRDS) technique utilizes a laser tuned to H− photo-detachment to measure the H− densities at inside LHIS. With successful development of these diagnostic techniques, any hidden or dormant capabilities in LHIS will be found and capitalized upon, both in its modelling and operation. Also, its potential benefit to LANSCE and LANL future needs will be realized. More generally, this will be the first use of these plasma diagnostic techniques on an accelerator based H− ion sources. We will present on the preliminary status of the diagnostic setup.
{"title":"Design of experiment to explore inside the LANSCE H− ion source with laser absorption techniques","authors":"D. Kleinjan, G. Rouleau, L. Neukirch","doi":"10.1063/5.0057840","DOIUrl":"https://doi.org/10.1063/5.0057840","url":null,"abstract":"The Los Alamos Neutron Science Center (LANSCE) H− ion source (LHIS) has provided stable output for decades of LANL mission needs. While several in-house improvements have been made to its stability and lifetime, its maximum beam output has remained the same at ~14 mA. While operationally well understood, the internal relationship between the LHIS plasma, cesium distribution (the catalyst for producing H− ions), and produced H− beam remains a mystery, only explored indirectly with models. We will develop fast, accurate, and non-invasive diagnostics techniques to measure the Cs and H− densities inside LHIS. These diagnostics are based on optical absorption spectroscopy that have been developed in the last decade for fusion based H- ion sources that can readily be applied to the accelerator based LHIS. A refined form of optical absorption spectroscopy, the laser absorption technique (LAT), utilizes lasers tuned to a given atomic species to measure its density. In this case a laser tuned to the D2 line of cesium will be used to determine its density inside LHIS. Similarly, a refined version of LAT called the cavity ring-ring down spectroscopy (CRDS) technique utilizes a laser tuned to H− photo-detachment to measure the H− densities at inside LHIS. With successful development of these diagnostic techniques, any hidden or dormant capabilities in LHIS will be found and capitalized upon, both in its modelling and operation. Also, its potential benefit to LANSCE and LANL future needs will be realized. More generally, this will be the first use of these plasma diagnostic techniques on an accelerator based H− ion sources. We will present on the preliminary status of the diagnostic setup.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79220764","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 continuous research and developments in the field of robotics have realized some important aspects of human behavior that has been incorporated into the mechanical systems. Similar to the human a robotic system can also handle the things skillfully with or without the knowledge of the model using the different intelligent control techniques. The present paper is a review work based on literatures of the controldesign techniques for theTwo-link robotic manipulator according to the control requirement. Thedifferent control techniques like PID control, Fuzzy logic control (FLC) and Artificial neural network (ANN) control with optimization of their optimal parameters using GA techniques has been considered and also the advantages and disadvantages of each control scheme over the conventional PID controller has been discussed. One of the main objectives of this present work is to provide the readers with the insights of the advancements and continuous developments in the field of robotic control and possess the wide range of application areas that has been taken place in the last few decades. Despite the fact that the traditional PID controller is used extensively in industries and automation due to its easy controldesign and low cost but it is associated with some major shortcomings such as uncertainties, non-linearity, varying payload and varying parameters of the robot manipulator do not make it a robust controller. Therefore, for the performance enhancements and accuracy of the controller the researchers have been mostly inclined towards the using of soft computing techniques which mainly comprises the model-free control technique over the conventional model-based PID control.
{"title":"Design and control of a two-link robotic manipulator: A review","authors":"Ranjan Kumar, Kaushik Kumar","doi":"10.1063/5.0057931","DOIUrl":"https://doi.org/10.1063/5.0057931","url":null,"abstract":"The continuous research and developments in the field of robotics have realized some important aspects of human behavior that has been incorporated into the mechanical systems. Similar to the human a robotic system can also handle the things skillfully with or without the knowledge of the model using the different intelligent control techniques. The present paper is a review work based on literatures of the controldesign techniques for theTwo-link robotic manipulator according to the control requirement. Thedifferent control techniques like PID control, Fuzzy logic control (FLC) and Artificial neural network (ANN) control with optimization of their optimal parameters using GA techniques has been considered and also the advantages and disadvantages of each control scheme over the conventional PID controller has been discussed. One of the main objectives of this present work is to provide the readers with the insights of the advancements and continuous developments in the field of robotic control and possess the wide range of application areas that has been taken place in the last few decades. Despite the fact that the traditional PID controller is used extensively in industries and automation due to its easy controldesign and low cost but it is associated with some major shortcomings such as uncertainties, non-linearity, varying payload and varying parameters of the robot manipulator do not make it a robust controller. Therefore, for the performance enhancements and accuracy of the controller the researchers have been mostly inclined towards the using of soft computing techniques which mainly comprises the model-free control technique over the conventional model-based PID control.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85044518","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}
B. Sridhar, KumarKaushik, Kumar G. Sateesh, PrasadB Anjaneya
{"title":"Preface: International Conference on Manufacturing, Material Science & Engineering ICMMSE 2020","authors":"B. Sridhar, KumarKaushik, Kumar G. Sateesh, PrasadB Anjaneya","doi":"10.1063/12.0005240","DOIUrl":"https://doi.org/10.1063/12.0005240","url":null,"abstract":"","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79534015","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}
Pin-fin and plate-fin heat sink augmented the heat transfer for the internal combustion engine, the electronic system, the gas turbine blades, and other applications. This is due to its versatility, budget-free, and well-founded production processes. Generally, perforated heat sinks show a higher pressure drop when compared to other types of heat sinks. The present paper aims to summarize the benefits of perforation for the pin-fin and plate-fin heat sinks with laminar or turbulent flow. The influence of perforation size, number, shape, and orientation of the different heat sink for the heat transfer enhancement and pressure dropreported in recent literature is discussed.
{"title":"Effect of perforated pin-fin and plate-fin heat sinks on heat transfer enhancement: A review of recent literature","authors":"Venkata Pradeep Yellala, Pradeep S. Jakkareddy","doi":"10.1063/5.0058145","DOIUrl":"https://doi.org/10.1063/5.0058145","url":null,"abstract":"Pin-fin and plate-fin heat sink augmented the heat transfer for the internal combustion engine, the electronic system, the gas turbine blades, and other applications. This is due to its versatility, budget-free, and well-founded production processes. Generally, perforated heat sinks show a higher pressure drop when compared to other types of heat sinks. The present paper aims to summarize the benefits of perforation for the pin-fin and plate-fin heat sinks with laminar or turbulent flow. The influence of perforation size, number, shape, and orientation of the different heat sink for the heat transfer enhancement and pressure dropreported in recent literature is discussed.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80059643","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}
D. Wünderlich, R. Riedl, F. Bonomo, S. Cristofaro, A. Hurlbatt, I. Mario, A. Mimo, R. Nocentini, W. Kraus, M. Peglau, B. Schmidt, B. Heinemann, U. Fantz
Beam extraction at the large ELISE test facility is currently possible only pulsed, with short extraction phases, so-called extraction blips, of up to 10 s each ≈150 s. Over the past years, a good insight into the physics of this operational mode has been gained for both hydrogen and deuterium operation. The uniformity of the co-extracted electrons was identified as a key issue and it was possible to achieve 1000 s plasma pulses in hydrogen with repetitive extraction blips and an extracted current density of over 90 % of the ITER target value by improving the co-extracted electron symmetry. In deuterium roughly 67 % of the ITER target for the extracted current density has been achieved for long pulses. During such pulses an overall increase of the co-extracted electron current is typically observed between one blip and the next one, even though the electron current is observed to actually decrease during each blip. These opposing effects are explained by different caesium dynamics during the source plasma phase when compared to the beam phase and they were one motivation behind the currently ongoing upgrade of ELISE to a CW extraction system. This update consists of two main hardware changes: i) installation of a new CW high voltage power supply and ii) installation of a CW beam calorimeter. Being able to achieve beam pulses of up to 1 hour will allow knowledge to be gained on the physics of caesium redistribution and conditioning over the long timescales needed for ITER operation.
{"title":"Transferring knowledge gained for pulsed extraction at the ELISE test facility to ITER-relevant CW extraction","authors":"D. Wünderlich, R. Riedl, F. Bonomo, S. Cristofaro, A. Hurlbatt, I. Mario, A. Mimo, R. Nocentini, W. Kraus, M. Peglau, B. Schmidt, B. Heinemann, U. Fantz","doi":"10.1063/5.0057534","DOIUrl":"https://doi.org/10.1063/5.0057534","url":null,"abstract":"Beam extraction at the large ELISE test facility is currently possible only pulsed, with short extraction phases, so-called extraction blips, of up to 10 s each ≈150 s. Over the past years, a good insight into the physics of this operational mode has been gained for both hydrogen and deuterium operation. The uniformity of the co-extracted electrons was identified as a key issue and it was possible to achieve 1000 s plasma pulses in hydrogen with repetitive extraction blips and an extracted current density of over 90 % of the ITER target value by improving the co-extracted electron symmetry. In deuterium roughly 67 % of the ITER target for the extracted current density has been achieved for long pulses. During such pulses an overall increase of the co-extracted electron current is typically observed between one blip and the next one, even though the electron current is observed to actually decrease during each blip. These opposing effects are explained by different caesium dynamics during the source plasma phase when compared to the beam phase and they were one motivation behind the currently ongoing upgrade of ELISE to a CW extraction system. This update consists of two main hardware changes: i) installation of a new CW high voltage power supply and ii) installation of a CW beam calorimeter. Being able to achieve beam pulses of up to 1 hour will allow knowledge to be gained on the physics of caesium redistribution and conditioning over the long timescales needed for ITER operation.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75188288","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 this work, the probability of negative ionization of hydrogen particles on low work function metal surfaces is calculated: an important parameter for the field of the surface plasma negative ion sources. We present the theoretical model for the computer calculation of the negative ionization probability. The key feature of our model is that the affinity level of the hydrogen atom is set constant near the surface; hence the calculated ionization probability does not depend heavily on the initial atom-surface distance.
{"title":"Theoretical calculation of the hydrogen negative ionization probability on the low work function surfaces","authors":"I. Gainullin, V. Dudnikov","doi":"10.1063/5.0057433","DOIUrl":"https://doi.org/10.1063/5.0057433","url":null,"abstract":"In this work, the probability of negative ionization of hydrogen particles on low work function metal surfaces is calculated: an important parameter for the field of the surface plasma negative ion sources. We present the theoretical model for the computer calculation of the negative ionization probability. The key feature of our model is that the affinity level of the hydrogen atom is set constant near the surface; hence the calculated ionization probability does not depend heavily on the initial atom-surface distance.","PeriodicalId":21797,"journal":{"name":"SEVENTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75518387","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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