Pub Date : 2014-09-08DOI: 10.1109/ICDL.2014.6893170
H. G. Tarchouna, N. Bonifaci, F. Aitken, V. Shakhatov, V. Atrazhev, J. Eloranta, K. von Haeften, N. Sadeghi, F. Jomni
The properties of corona discharge were study by electro-physical and spectral methods in the supercritical phase at 6 K and 11 K as well as in normal liquid helium at 4.2K within the pressure range of 0.1-10 MPa. The electro-physical investigations (measurement of corona current as a function of the applied voltage) gave information about the mobility of charged particles in the medium. The observed corona current is very small, less than 10-7 A. The measured current-voltage characteristics allow for the calculation of the charged particle mobilities (i.e., electrons for negative corona and positive ions for positive corona). The observed charge mobilities decrease as a function of external pressure in both supercritical and liquid phases of helium. The light emitted from the ionization zone was analyzed and assigned to atomic and molecular lines. Distortion of the spectral lines due to the dense helium environment was analyzed. The observed P and R branch rotational line shifts of He2* are markedly different from the previous theoretical predictions. The observed atomic line shifts and widths depend strongly on the applied pressure in both the supercritical and the liquid phases, which can be understood in terms of a bubble formation around the emitters.
{"title":"Molecular and atomic spectra emitted by normal liquid and supercritical 4He excited by corona discharge","authors":"H. G. Tarchouna, N. Bonifaci, F. Aitken, V. Shakhatov, V. Atrazhev, J. Eloranta, K. von Haeften, N. Sadeghi, F. Jomni","doi":"10.1109/ICDL.2014.6893170","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893170","url":null,"abstract":"The properties of corona discharge were study by electro-physical and spectral methods in the supercritical phase at 6 K and 11 K as well as in normal liquid helium at 4.2K within the pressure range of 0.1-10 MPa. The electro-physical investigations (measurement of corona current as a function of the applied voltage) gave information about the mobility of charged particles in the medium. The observed corona current is very small, less than 10-7 A. The measured current-voltage characteristics allow for the calculation of the charged particle mobilities (i.e., electrons for negative corona and positive ions for positive corona). The observed charge mobilities decrease as a function of external pressure in both supercritical and liquid phases of helium. The light emitted from the ionization zone was analyzed and assigned to atomic and molecular lines. Distortion of the spectral lines due to the dense helium environment was analyzed. The observed P and R branch rotational line shifts of He2* are markedly different from the previous theoretical predictions. The observed atomic line shifts and widths depend strongly on the applied pressure in both the supercritical and the liquid phases, which can be understood in terms of a bubble formation around the emitters.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"82 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76108441","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893080
S. Serra, M. Fattori, P. Morshuis, G. Montanari
In order to answer technologically to the challenge of measuring and monitoring oil corrosivity and corrosive sulphur dissolved in oil, a new sensor has been designed to measure quantitatively the corrosivity of oil during service operation. The sensor has an intelligent measuring head which manages the whole measuring process according to ASTM D1275 A and B and IEC 62535 for spot measurements (within 24 h up to 72 h), or also through permanent monitoring of the transformer. In both cases, the measurements are done in situ (with the sensor installed on the transformer), avoiding cumbersome and expensive procedures and oil sampling, since the sensor can be easily installed at the transformer valves. The sensor has two active parts which highlight different aspects of the oil corrosion process: the first measures directly the corrosion level on the copper through a suitable sensor, while the second displays the threat level of the byproducts of the copper corrosion, by measuring the change of conductivity of the dielectric as a consequence of such byproducts accumulation. In this way a robust and accurate method for the assessment of the overall corrosion process and its effect on the transformer is obtained, lowering considerably the possibility of false alarms. In this paper a number of real case tests of the sensor are presented, and results are discussed, providing evidence of the effectiveness of this new technological device.
{"title":"A new advanced Sensor for corrosive sulphur detection and monitoring","authors":"S. Serra, M. Fattori, P. Morshuis, G. Montanari","doi":"10.1109/ICDL.2014.6893080","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893080","url":null,"abstract":"In order to answer technologically to the challenge of measuring and monitoring oil corrosivity and corrosive sulphur dissolved in oil, a new sensor has been designed to measure quantitatively the corrosivity of oil during service operation. The sensor has an intelligent measuring head which manages the whole measuring process according to ASTM D1275 A and B and IEC 62535 for spot measurements (within 24 h up to 72 h), or also through permanent monitoring of the transformer. In both cases, the measurements are done in situ (with the sensor installed on the transformer), avoiding cumbersome and expensive procedures and oil sampling, since the sensor can be easily installed at the transformer valves. The sensor has two active parts which highlight different aspects of the oil corrosion process: the first measures directly the corrosion level on the copper through a suitable sensor, while the second displays the threat level of the byproducts of the copper corrosion, by measuring the change of conductivity of the dielectric as a consequence of such byproducts accumulation. In this way a robust and accurate method for the assessment of the overall corrosion process and its effect on the transformer is obtained, lowering considerably the possibility of false alarms. In this paper a number of real case tests of the sensor are presented, and results are discussed, providing evidence of the effectiveness of this new technological device.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"83 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88993292","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893122
Y. Stishkov, I. Ashikhmin
This paper presents the results of computer simulation of EHD flows in a symmetric wire-wire electrode system at different values of low-voltage conductivity. The simulation used the finite element method on the basis of the Poisson, the Navier-Stokes, and the Nernst-Planck equations. The level of the low-voltage conductivity was found not only to affect the electrical current, but also to change the structure of arising EHD flows.
{"title":"Simulation of EHD flows in a symmetric two wire electrode system at different values of low-voltage conductivity","authors":"Y. Stishkov, I. Ashikhmin","doi":"10.1109/ICDL.2014.6893122","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893122","url":null,"abstract":"This paper presents the results of computer simulation of EHD flows in a symmetric wire-wire electrode system at different values of low-voltage conductivity. The simulation used the finite element method on the basis of the Poisson, the Navier-Stokes, and the Nernst-Planck equations. The level of the low-voltage conductivity was found not only to affect the electrical current, but also to change the structure of arising EHD flows.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"17 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88841761","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893101
X. Yang, S. Nielsen, G. Ledwich
Frequency Domain Spectroscopy (FDS) is successfully being used to assess the insulation condition of oil filled power transformers. However, it has to date only been implemented on de-energized transformers, which requires the transformers to be shut down for an extended period which can result in significant costs. To solve this issue, a method of implementing FDS under energized condition is proposed here. A chirp excitation waveform is used to replace the conventional sinusoidal waveform to reduce the measurement time in this method. Investigation of the dielectric response under the influence of a high voltage stress at power frequency is reported based on experimental results. To further understand the insulation ageing process, the geometric capacitance effect is removed to enhance the detection of the ageing signature. This enhancement enables the imaginary part of admittance to be used as a new indicator to assess the ageing status of the insulation.
{"title":"Experimental investigations of improved dielectric condition monitoring methods on transformer oil-paper insulation system","authors":"X. Yang, S. Nielsen, G. Ledwich","doi":"10.1109/ICDL.2014.6893101","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893101","url":null,"abstract":"Frequency Domain Spectroscopy (FDS) is successfully being used to assess the insulation condition of oil filled power transformers. However, it has to date only been implemented on de-energized transformers, which requires the transformers to be shut down for an extended period which can result in significant costs. To solve this issue, a method of implementing FDS under energized condition is proposed here. A chirp excitation waveform is used to replace the conventional sinusoidal waveform to reduce the measurement time in this method. Investigation of the dielectric response under the influence of a high voltage stress at power frequency is reported based on experimental results. To further understand the insulation ageing process, the geometric capacitance effect is removed to enhance the detection of the ageing signature. This enhancement enables the imaginary part of admittance to be used as a new indicator to assess the ageing status of the insulation.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"27 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88137980","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893163
Jian Wu, P. Traoré, C. Louste, A. Pérez, P. Vázquez
The electrohydroyanmic (EHD) plume induced by charge injection from a hyperbolic blade into a dielectric liquid was considered to actively enhance heat transfer. We numerically studied an upward-facing hot plate with constant temperature cooled by an impinging ionic jet that results from a strong and autonomous injection. It is shown that the heat transfer rate expressed with the local and averaged Nusselt numbers are dramatically increased. In addition, we observe that the Nusselt number is independent of the Rayleigh number Ra (2.5×103 ≤ Ra ≤ 1.0×104) for all electric Rayleigh numbers T considered (5.0×102 ≤ T ≤ 2.0×104 ), which reflects the fully dominant role of the electric force.
{"title":"Heat transfer enhancement by an electrohydrodynamic plume induced by ion injection from a hyperbolic blade","authors":"Jian Wu, P. Traoré, C. Louste, A. Pérez, P. Vázquez","doi":"10.1109/ICDL.2014.6893163","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893163","url":null,"abstract":"The electrohydroyanmic (EHD) plume induced by charge injection from a hyperbolic blade into a dielectric liquid was considered to actively enhance heat transfer. We numerically studied an upward-facing hot plate with constant temperature cooled by an impinging ionic jet that results from a strong and autonomous injection. It is shown that the heat transfer rate expressed with the local and averaged Nusselt numbers are dramatically increased. In addition, we observe that the Nusselt number is independent of the Rayleigh number Ra (2.5×10<sup>3</sup> ≤ Ra ≤ 1.0×10<sup>4</sup>) for all electric Rayleigh numbers T considered (5.0×10<sup>2</sup> ≤ T ≤ 2.0×10<sup>4</sup> ), which reflects the fully dominant role of the electric force.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86937689","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893143
Yuan Zhou, M. Hao, George Chen, P. Jarman, G. Wilson
Dielectric spectroscopy is non-invasive diagnostic method and can give information about dipole relaxation, electrical conduction and structure of molecules. Since the creation of charge carriers in mineral oil is not only from dissociation but also injection from electrodes, the injection current cannot be simply ignored. The polarization caused by the charge injection has been studied in this paper. Based on our research, if the mobility of the injected charge carriers is fast enough so that they can reach the opposite electrode, the current caused by the injection will contribute only to the imaginary part of the complex permittivity and this part of the complex permittivity will decrease with the frequency with a slope of -1 which is in a good agreement with the experimental result. The classic ionic drift and diffusion model and this injection model will be combined to make an improved model. In this paper, the frequency responses of three different kinds of mineral oils have been measured, and this modified model has been used to simulate the experiment result. Since there is only one unknown parameter in this improved model, a better understanding of the frequency response in mineral oil can be achieved.
{"title":"A new approach to understanding the frequency response of mineral oil","authors":"Yuan Zhou, M. Hao, George Chen, P. Jarman, G. Wilson","doi":"10.1109/ICDL.2014.6893143","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893143","url":null,"abstract":"Dielectric spectroscopy is non-invasive diagnostic method and can give information about dipole relaxation, electrical conduction and structure of molecules. Since the creation of charge carriers in mineral oil is not only from dissociation but also injection from electrodes, the injection current cannot be simply ignored. The polarization caused by the charge injection has been studied in this paper. Based on our research, if the mobility of the injected charge carriers is fast enough so that they can reach the opposite electrode, the current caused by the injection will contribute only to the imaginary part of the complex permittivity and this part of the complex permittivity will decrease with the frequency with a slope of -1 which is in a good agreement with the experimental result. The classic ionic drift and diffusion model and this injection model will be combined to make an improved model. In this paper, the frequency responses of three different kinds of mineral oils have been measured, and this modified model has been used to simulate the experiment result. Since there is only one unknown parameter in this improved model, a better understanding of the frequency response in mineral oil can be achieved.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"9 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83718834","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893111
V. Haramija, D. Vrsaljko, V. Durina
Synthetic esters are interesting as transformer insulating liquids for use in densely populated and environmentally sensitive areas because of high flashpoint, good biodegradability, low toxicity, good electrical and thermal properties, resistance to electrical discharges and compatibility with materials in transformers. Monitoring of liquid insulation is a convenient method for assessing general condition of the transformer. Since synthetic esters have only recently been put into use in power transformers, there is still not enough data on change of their properties during exploitation for transformer condition assessment. Monitoring changes of properties in laboratory ageing conditions, as well as the determination of characteristic degradation products will contribute to a better understanding of the insulating liquid and to the assessment of its functionality. In this paper, changes of physico-chemical properties of synthetic ester-based transformer oil in laboratory ageing conditions were investigated. The oil was submitted to 120 °C and 150 °C at different time intervals. After the exposure to high temperature, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed. DSC was performed for the purpose of gathering qualitative and quantitative data about physical and chemical processes that include endothermic and exothermic effects and heat capacity change. Heat capacity is highly affected by viscosity, so temperature dependence of viscosity as well as viscosity change during ageing was monitored. TGA was performed for the purpose of material characterization and gathering of information about thermal stability of oil. The investigation contributes to better understanding of thermal ageing kinetics of environmentally friendly synthetic ester-based insulating liquid.
{"title":"Thermal properties of synthetic ester-based transformer oil during ageing in laboratory conditions","authors":"V. Haramija, D. Vrsaljko, V. Durina","doi":"10.1109/ICDL.2014.6893111","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893111","url":null,"abstract":"Synthetic esters are interesting as transformer insulating liquids for use in densely populated and environmentally sensitive areas because of high flashpoint, good biodegradability, low toxicity, good electrical and thermal properties, resistance to electrical discharges and compatibility with materials in transformers. Monitoring of liquid insulation is a convenient method for assessing general condition of the transformer. Since synthetic esters have only recently been put into use in power transformers, there is still not enough data on change of their properties during exploitation for transformer condition assessment. Monitoring changes of properties in laboratory ageing conditions, as well as the determination of characteristic degradation products will contribute to a better understanding of the insulating liquid and to the assessment of its functionality. In this paper, changes of physico-chemical properties of synthetic ester-based transformer oil in laboratory ageing conditions were investigated. The oil was submitted to 120 °C and 150 °C at different time intervals. After the exposure to high temperature, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed. DSC was performed for the purpose of gathering qualitative and quantitative data about physical and chemical processes that include endothermic and exothermic effects and heat capacity change. Heat capacity is highly affected by viscosity, so temperature dependence of viscosity as well as viscosity change during ageing was monitored. TGA was performed for the purpose of material characterization and gathering of information about thermal stability of oil. The investigation contributes to better understanding of thermal ageing kinetics of environmentally friendly synthetic ester-based insulating liquid.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"59 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86784396","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893160
Y. Xia, J. Reboud, P. Atten
Drop-on-demand technique was developed, based on multi-stage high voltage electric pulse applied on conductive liquid meniscus hanging from a needle [1]. It is applied to the injection of a water droplet in oil, and allows injecting droplets from the same needle in a wide range of diameter, smaller than the needle one. The paper presents experiments of droplet injection in two types of mineral oil: Marcol 52, Primol 352, for varying interface tension and viscosity parameters. High speed video and numerical simulations helped understanding the main physical effects occurring during water droplet formation.
{"title":"Influence of viscosity and interface tension on water droplet injection in oil","authors":"Y. Xia, J. Reboud, P. Atten","doi":"10.1109/ICDL.2014.6893160","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893160","url":null,"abstract":"Drop-on-demand technique was developed, based on multi-stage high voltage electric pulse applied on conductive liquid meniscus hanging from a needle [1]. It is applied to the injection of a water droplet in oil, and allows injecting droplets from the same needle in a wide range of diameter, smaller than the needle one. The paper presents experiments of droplet injection in two types of mineral oil: Marcol 52, Primol 352, for varying interface tension and viscosity parameters. High speed video and numerical simulations helped understanding the main physical effects occurring during water droplet formation.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"15 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84412418","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893104
Ken-ichi Itoh, T. Yamazaki, R. Hanaoka, Y. Katagiri, K. Miyagi, Y. Kanamaru, K. Takamoto, T. Kano
Two different kinds of attempts were made to measure ion mobilities in EHD liquids by using the time-of-flight technique. The first attempt was a reverse polarity method which was similar to that used by L. Yang et al. [5]. The stainless steel coaxial cylindrical electrodes with the effective length of 55 mm and the electrode spacing of 1.5 mm were utilized. The purified two sample liquids; hydrofluoroether (HFE7600) and 2, 3-dihydrodecafluoropentane (HFC43-10) with very low dark current (less than 20 pA at 150 V) were used. In this attempt, it is deduced that the mobility value is of the order of 1×10-8 m2/Vs. In the second attempt, the plate-mesh-plate electrode configuration was employed. One plate was used to apply high voltage pulses and the other plate worked as a counter electrode. The center mesh electrode was kept at low dc voltages. This triode electrode design allows us to monitor the amount of charge injected from the charge injection space to the charge detection space through the mesh electrode during and after the high voltage pulse. Two sample liquids; HFE 7600 and HFC43-10 were used without any purification. Ion drift currents were found to have very long tails. If the tails are included into the drift times, the mobility of ions can be as low as approximately 1×10-9 m2/Vs in both liquids.
{"title":"Attempts to measure ion mobilities in EHD liquids by the time-of-flight method","authors":"Ken-ichi Itoh, T. Yamazaki, R. Hanaoka, Y. Katagiri, K. Miyagi, Y. Kanamaru, K. Takamoto, T. Kano","doi":"10.1109/ICDL.2014.6893104","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893104","url":null,"abstract":"Two different kinds of attempts were made to measure ion mobilities in EHD liquids by using the time-of-flight technique. The first attempt was a reverse polarity method which was similar to that used by L. Yang et al. [5]. The stainless steel coaxial cylindrical electrodes with the effective length of 55 mm and the electrode spacing of 1.5 mm were utilized. The purified two sample liquids; hydrofluoroether (HFE7600) and 2, 3-dihydrodecafluoropentane (HFC43-10) with very low dark current (less than 20 pA at 150 V) were used. In this attempt, it is deduced that the mobility value is of the order of 1×10-8 m2/Vs. In the second attempt, the plate-mesh-plate electrode configuration was employed. One plate was used to apply high voltage pulses and the other plate worked as a counter electrode. The center mesh electrode was kept at low dc voltages. This triode electrode design allows us to monitor the amount of charge injected from the charge injection space to the charge detection space through the mesh electrode during and after the high voltage pulse. Two sample liquids; HFE 7600 and HFC43-10 were used without any purification. Ion drift currents were found to have very long tails. If the tails are included into the drift times, the mobility of ions can be as low as approximately 1×10-9 m2/Vs in both liquids.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"55 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76469182","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 : 2014-09-08DOI: 10.1109/ICDL.2014.6893166
J. Masbou, J. Cussonneau, J. Donnard, L. G. Manzano, O. L. P. Leray, A.-F Mohamed Hadi, E. Morteau, L. Lavina, J. Stutzmann, D. Thers, S. Bassetto, P. Briend, M. Górski, N. Beaupère, T. Carlier, M. Chérel, F. Kraeber-Bodéré
In the context of medical imaging system, we develop an innovative technique, called 3 gamma. It consists in a direct 3D reconstruction of each decays of 44Sc radionuclide with a resolution below the centimeter. This breakthrough in instrumentation technique is only possible by the use of a new detection medium (liquid xenon) and a new detection structure compared with conventional imaging technique. Thanks to an ultra-low noise front-end electronics (below 100 electrons ENC) operating at liquid xenon temperature and a fast UV sensitive PMT, high spatial resolution and high energy resolution are achievable in 3D. This is particularly important for Compton imaging since all interactions in the medium have to be identified to derive the incoming gamma ray direction. A prototype (XEMIS1) is now in test at Subatech and shows promising results. We achieve an energy resolution of 8.9 % (FWHM) at 1.2 MeV with an electric field of 1kV/cm. All the cryogenic system is fully operational with a high purification rate and shows a very good stability. I will review all these aspects and introduce the next step of the project, XEMIS2, a larger prototype dedicated to the 3 gamma imaging of small animals.
{"title":"XEMIS: A new Compton camera with liquid xenon","authors":"J. Masbou, J. Cussonneau, J. Donnard, L. G. Manzano, O. L. P. Leray, A.-F Mohamed Hadi, E. Morteau, L. Lavina, J. Stutzmann, D. Thers, S. Bassetto, P. Briend, M. Górski, N. Beaupère, T. Carlier, M. Chérel, F. Kraeber-Bodéré","doi":"10.1109/ICDL.2014.6893166","DOIUrl":"https://doi.org/10.1109/ICDL.2014.6893166","url":null,"abstract":"In the context of medical imaging system, we develop an innovative technique, called 3 gamma. It consists in a direct 3D reconstruction of each decays of 44Sc radionuclide with a resolution below the centimeter. This breakthrough in instrumentation technique is only possible by the use of a new detection medium (liquid xenon) and a new detection structure compared with conventional imaging technique. Thanks to an ultra-low noise front-end electronics (below 100 electrons ENC) operating at liquid xenon temperature and a fast UV sensitive PMT, high spatial resolution and high energy resolution are achievable in 3D. This is particularly important for Compton imaging since all interactions in the medium have to be identified to derive the incoming gamma ray direction. A prototype (XEMIS1) is now in test at Subatech and shows promising results. We achieve an energy resolution of 8.9 % (FWHM) at 1.2 MeV with an electric field of 1kV/cm. All the cryogenic system is fully operational with a high purification rate and shows a very good stability. I will review all these aspects and introduce the next step of the project, XEMIS2, a larger prototype dedicated to the 3 gamma imaging of small animals.","PeriodicalId":6523,"journal":{"name":"2014 IEEE 18th International Conference on Dielectric Liquids (ICDL)","volume":"103 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2014-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75950088","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：