Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202881
I. Lopes, W. Schmidt
The natural and radiation-induced electric conductivity of liquid tungsten hexafluoride was investigated. Due to the large electron transfer of WF/sub 6/ the barrier for electron transfer from the metal cathode into the liquid is less than 1 eV. Formation of negative ions near the cathode takes place and the magnitude of the current density is determined by the rate of escape of these ions due to diffusion and externally applied electric field. The radiation-induced charge-carrier yield was measured as a function of the electric field strength. Although the ion yield per unit of absorbed energy is much smaller than in hydrocarbons, due to the high-density WF/sub 6/ a comparable number of ions is produced if equal volumes are compared.<>
{"title":"Passage of electrical current through liquid tungsten hexafluoride","authors":"I. Lopes, W. Schmidt","doi":"10.1109/ICDL.1990.202881","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202881","url":null,"abstract":"The natural and radiation-induced electric conductivity of liquid tungsten hexafluoride was investigated. Due to the large electron transfer of WF/sub 6/ the barrier for electron transfer from the metal cathode into the liquid is less than 1 eV. Formation of negative ions near the cathode takes place and the magnitude of the current density is determined by the rate of escape of these ions due to diffusion and externally applied electric field. The radiation-induced charge-carrier yield was measured as a function of the electric field strength. Although the ion yield per unit of absorbed energy is much smaller than in hydrocarbons, due to the high-density WF/sub 6/ a comparable number of ions is produced if equal volumes are compared.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115367039","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202875
G. Charpak, V. Peskov, D. Scigocki
Two types of liquid photocathodes were investigated: semitransparent and reflective. Experiments have led to the conclusion that, in the case of semitransparent photocathodes, the photoemission increases strongly at certain thicknesses, when the electron temperature of the photoelectrons obtained in the applied electric field is higher than the conduction-band energy of the liquid. In the case of reflective cathodes, a thin intermediate layer of vapor between the liquid and the gaseous phases contributes strongly to the production of photoelectrons. The main application of the photocathodes described is in very fast gaseous detectors for the detection of VUV (vacuum ultraviolet) photons.<>
{"title":"Liquid and solid photocathodes and their applications for fast gaseous detectors","authors":"G. Charpak, V. Peskov, D. Scigocki","doi":"10.1109/ICDL.1990.202875","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202875","url":null,"abstract":"Two types of liquid photocathodes were investigated: semitransparent and reflective. Experiments have led to the conclusion that, in the case of semitransparent photocathodes, the photoemission increases strongly at certain thicknesses, when the electron temperature of the photoelectrons obtained in the applied electric field is higher than the conduction-band energy of the liquid. In the case of reflective cathodes, a thin intermediate layer of vapor between the liquid and the gaseous phases contributes strongly to the production of photoelectrons. The main application of the photocathodes described is in very fast gaseous detectors for the detection of VUV (vacuum ultraviolet) photons.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"26-27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116775945","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202854
H. Faidas, L. Christophorou, D. McCorkle
The drift velocity, w, of excess electrons as a function of the applied uniform electric field, E, in liquid 2,2-dimethylpropane (TMC), tetramethylsilane (TMS), tetramethylgermanium (TMG), tetramethyltin (TMT), and 2,2,4,4-tetramethylpentane (TMP), as well as in mixtures of TMS with TMP (mole ratio M=1.31/1) and n-pentane (M=102/1, 17/1, and 5.6/1), has been measured for E-values up to approximately 10/sup 5/ V-cm/sup -1/. The thermal electron mobility in the above liquids is 71.5, 119.3, 114.7, 85.7, 31.8, 39.1, 118, 85, and 47.6 cm/sup 2/ s/sup -1/ V/sup -1/, respectively. Electrical breakdown in TMS, TMP, and the mixtures occurred at E>16/sup 5/ V-cm/sup -1/. In TMT it occurred at rather low fields (E not=7.5*10/sup 4/ V-cm/sup -1/), and it led to significant decomposition of the liquid and deposition of tin on the cell walls and the electrodes. In TMC and TMG no breakdown occurred up to the highest field reached.<>
{"title":"Electron transport in fast dielectric liquids at high applied electric fields","authors":"H. Faidas, L. Christophorou, D. McCorkle","doi":"10.1109/ICDL.1990.202854","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202854","url":null,"abstract":"The drift velocity, w, of excess electrons as a function of the applied uniform electric field, E, in liquid 2,2-dimethylpropane (TMC), tetramethylsilane (TMS), tetramethylgermanium (TMG), tetramethyltin (TMT), and 2,2,4,4-tetramethylpentane (TMP), as well as in mixtures of TMS with TMP (mole ratio M=1.31/1) and n-pentane (M=102/1, 17/1, and 5.6/1), has been measured for E-values up to approximately 10/sup 5/ V-cm/sup -1/. The thermal electron mobility in the above liquids is 71.5, 119.3, 114.7, 85.7, 31.8, 39.1, 118, 85, and 47.6 cm/sup 2/ s/sup -1/ V/sup -1/, respectively. Electrical breakdown in TMS, TMP, and the mixtures occurred at E>16/sup 5/ V-cm/sup -1/. In TMT it occurred at rather low fields (E not=7.5*10/sup 4/ V-cm/sup -1/), and it led to significant decomposition of the liquid and deposition of tin on the cell walls and the electrodes. In TMC and TMG no breakdown occurred up to the highest field reached.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125065486","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202890
A. Zhakin
The electrohydrodynamics of liquid dielectrics with dissociation and injection conductivity is considered. The dissociation process is due to the reaction A/sup +/B/sup -/ from or to A/sup +/+B/sup -/. Injection occurs on the cathode according to the following scheme: X+e/sup -/ from or to X/sup -/. It takes into account the recombination of ions A/sup +/ and X/sup -/.<>
{"title":"Electrohydrodynamics of liquid dielectrics based on the ideal red-ox systems","authors":"A. Zhakin","doi":"10.1109/ICDL.1990.202890","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202890","url":null,"abstract":"The electrohydrodynamics of liquid dielectrics with dissociation and injection conductivity is considered. The dissociation process is due to the reaction A/sup +/B/sup -/ from or to A/sup +/+B/sup -/. Injection occurs on the cathode according to the following scheme: X+e/sup -/ from or to X/sup -/. It takes into account the recombination of ions A/sup +/ and X/sup -/.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125420239","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202938
C. Fenimore, K. Stricklett, H. Yamashita, H. Kawai, E. Forster, M. Pompili
Electrical measurements of perfluorinated polyethers were performed to determine the suitability of this class of material as a liquid dielectric. Measures of the breakdown strength and streamer inception voltage are obtained under electrical impulse stress. The breakdown strength is nearly independent of polarity. Under high magnification photography the cathode-originated streamers are seen to have a subsonic mode of growth. The transition to fast growth occurs on time and spatial scales shorter than those found in liquid hydrocarbons. The gas-phase electrical properties and the high heat of vaporization of this material are considered as mechanisms for this behavior.<>
{"title":"The inception and structure of prebreakdown streamers in perfluorinated polyethers","authors":"C. Fenimore, K. Stricklett, H. Yamashita, H. Kawai, E. Forster, M. Pompili","doi":"10.1109/ICDL.1990.202938","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202938","url":null,"abstract":"Electrical measurements of perfluorinated polyethers were performed to determine the suitability of this class of material as a liquid dielectric. Measures of the breakdown strength and streamer inception voltage are obtained under electrical impulse stress. The breakdown strength is nearly independent of polarity. Under high magnification photography the cathode-originated streamers are seen to have a subsonic mode of growth. The transition to fast growth occurs on time and spatial scales shorter than those found in liquid hydrocarbons. The gas-phase electrical properties and the high heat of vaporization of this material are considered as mechanisms for this behavior.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127667043","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202883
K. Yoshino, K. Sawada, S. Morita, Y. Nishioka, M. Fukuda, T. Kawai, Y. Ohmori
Conducting polymers with substituted long side chain such as poly(3-alkylthiophene), poly(3-alkyl-selenophene), poly(3alkylfuran), poly(9-alkylfluorene), and poly(9,9-dialkylfluorene) are shown to melt at relatively low temperature. Electrical conductivity and photoluminescence exhibit an anomalous dependence on molecular structures at the melting point. A marked polarity effect of photoconduction has been observed. These results are discussed in terms of unique band schemes of the conducting polymers in the premelting region and in the liquid state.<>
{"title":"Electrical and optical properties of liquid conducting polymer","authors":"K. Yoshino, K. Sawada, S. Morita, Y. Nishioka, M. Fukuda, T. Kawai, Y. Ohmori","doi":"10.1109/ICDL.1990.202883","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202883","url":null,"abstract":"Conducting polymers with substituted long side chain such as poly(3-alkylthiophene), poly(3-alkyl-selenophene), poly(3alkylfuran), poly(9-alkylfluorene), and poly(9,9-dialkylfluorene) are shown to melt at relatively low temperature. Electrical conductivity and photoluminescence exhibit an anomalous dependence on molecular structures at the melting point. A marked polarity effect of photoconduction has been observed. These results are discussed in terms of unique band schemes of the conducting polymers in the premelting region and in the liquid state.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125979196","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202928
K. Stricklett, E. F. Kelley, H. Yamashita, C. Fenimore, M. Pace, T. V. Blalock, A. Wintenberg, I. Alexeff
Partial discharges are observed in hexane by shadow photography under the application of DC voltages. A nonuniform field geometry is used and the growth of cavities associated with partial discharges at a point cathode was photographed at 200* magnification. The use of an image-preserving optical delay allows a record of the conditions which exist in the liquid prior to the initiation of the low-density streamer to be obtained. The cavity growth at a point cathode is anisotropic, which suggests that electrostatic forces are of primary importance in driving its expansion. The onset of instabilities in the cavity wall is suggested. The initial partial discharge current pulse precedes or is concurrent with the growth of the cavity. An upper bound of 60 ns between first current pulse and the growth of the cavity is obtained.<>
{"title":"Observations of partial discharges in hexane under high magnification","authors":"K. Stricklett, E. F. Kelley, H. Yamashita, C. Fenimore, M. Pace, T. V. Blalock, A. Wintenberg, I. Alexeff","doi":"10.1109/ICDL.1990.202928","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202928","url":null,"abstract":"Partial discharges are observed in hexane by shadow photography under the application of DC voltages. A nonuniform field geometry is used and the growth of cavities associated with partial discharges at a point cathode was photographed at 200* magnification. The use of an image-preserving optical delay allows a record of the conditions which exist in the liquid prior to the initiation of the low-density streamer to be obtained. The cavity growth at a point cathode is anisotropic, which suggests that electrostatic forces are of primary importance in driving its expansion. The onset of instabilities in the cavity wall is suggested. The initial partial discharge current pulse precedes or is concurrent with the growth of the cavity. An upper bound of 60 ns between first current pulse and the growth of the cavity is obtained.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132082871","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202930
M. Qureshi, W. G. Chadband
The occurrence of prebreakdown pulses at a point cathode under DC has been observed to be strongly influenced by insulating-liquid viscosity. Using a high bandwidth detection system it is revealed that each burst is composed of a well-structured set of pulses which increase in amplitude, initially in a linear fashion, with time before becoming irregular. The order of occurrence of these pulses and the time lapse obeys a proper law, and the total time domain of this linear regime is viscosity-dependent. Increasing the viscosity results in an increase in the duration of the burst and in the time interval between the pulses within the burst. Using the onset of each pulse or burst to trigger the capture of a shadowgraph produces an associated low-density region. The size of the shadow region increases with the burst duration. A preliminary model for the initial growth of the low-density region associated with these pulses is presented.<>
{"title":"Effect of viscosity on pre-breakdown conduction pulses at a point cathode in silicone oils","authors":"M. Qureshi, W. G. Chadband","doi":"10.1109/ICDL.1990.202930","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202930","url":null,"abstract":"The occurrence of prebreakdown pulses at a point cathode under DC has been observed to be strongly influenced by insulating-liquid viscosity. Using a high bandwidth detection system it is revealed that each burst is composed of a well-structured set of pulses which increase in amplitude, initially in a linear fashion, with time before becoming irregular. The order of occurrence of these pulses and the time lapse obeys a proper law, and the total time domain of this linear regime is viscosity-dependent. Increasing the viscosity results in an increase in the duration of the burst and in the time interval between the pulses within the burst. Using the onset of each pulse or burst to trigger the capture of a shadowgraph produces an associated low-density region. The size of the shadow region increases with the burst duration. A preliminary model for the initial growth of the low-density region associated with these pulses is presented.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133400338","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202971
S. Komin, E. Morozov, A. Ostapenko, Y.K. Stishkov
An analysis of theoretical calculations of the distribution charge and Coulomb forces in liquid dielectrics indicates that the variations of parameters of surface-charge formation in the electrode-liquid dielectric system lead to substantial variations in the character of the distribution. Results concerning the effect of electrode surface properties on the electric strength of liquid dielectrics are presented. It is shown that modification of interface properties, whether by electrode material or by introducing impurities, substantially changes the electric breakdown strength of the electrode-liquid system.<>
{"title":"Influence of electrode-liquid interface properties on breakdown voltage of liquid dielectrics","authors":"S. Komin, E. Morozov, A. Ostapenko, Y.K. Stishkov","doi":"10.1109/ICDL.1990.202971","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202971","url":null,"abstract":"An analysis of theoretical calculations of the distribution charge and Coulomb forces in liquid dielectrics indicates that the variations of parameters of surface-charge formation in the electrode-liquid dielectric system lead to substantial variations in the character of the distribution. Results concerning the effect of electrode surface properties on the electric strength of liquid dielectrics are presented. It is shown that modification of interface properties, whether by electrode material or by introducing impurities, substantially changes the electric breakdown strength of the electrode-liquid system.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133485999","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}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202877
A. Barabash
New experimental facilities for the detection of 2 beta -decay are discussed. It is shown that liquid ionization chambers are rather promising in this respect. A 30-liter liquid ionization chamber with an expected sensitivity of (0.3-1)*10/sup 24/ years for 2 beta (0 nu )-decay is discussed.<>
{"title":"Liquid ionization detectors and experiments on the search for 2 beta -decay","authors":"A. Barabash","doi":"10.1109/ICDL.1990.202877","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202877","url":null,"abstract":"New experimental facilities for the detection of 2 beta -decay are discussed. It is shown that liquid ionization chambers are rather promising in this respect. A 30-liter liquid ionization chamber with an expected sensitivity of (0.3-1)*10/sup 24/ years for 2 beta (0 nu )-decay is discussed.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131325980","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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