Pub Date : 1968-11-01DOI: 10.1088/0022-3735/1/11/306
M Bauer
A new method is described for determining the flux density distribution in magnetic electron lenses of finite permeability. The method involves a simple modification to the resistance network analogue of the magnetic circuit. Pole piece flux densities have been determined under normal and saturation conditions in a high power objective lens. The influence of pole piece saturation on the axial field distribution is discussed.
{"title":"Pole piece saturation in magnetic electron lenses.","authors":"M Bauer","doi":"10.1088/0022-3735/1/11/306","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/306","url":null,"abstract":"A new method is described for determining the flux density distribution in magnetic electron lenses of finite permeability. The method involves a simple modification to the resistance network analogue of the magnetic circuit. Pole piece flux densities have been determined under normal and saturation conditions in a high power objective lens. The influence of pole piece saturation on the axial field distribution is discussed.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/306","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16783111","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 : 1968-11-01DOI: 10.1088/0022-3735/1/11/303
K C Kao, T W Davies
A double beam spectrophotometer is described, suitable for the measurements of very low attenuation coefficients in glass in the wavelength range 500-1000 nm. The instrument is shown to have a balance stability of ±1 × 10−5. The systematic errors involved in the use of the long samples required for these measurements are studied. The instrument is shown to be satisfactory in making measurements of attenuation coefficients of 00001 cm−1 with an accuracy to ±0000 01 cm−1 when sample pairs of 20 cm length difference are used. Results of measurements on very low loss silica, which illustrate the performance of the instrument, are given.
{"title":"Spectrophotometric studies of ultra low loss optical glasses. I. Single beam method.","authors":"K C Kao, T W Davies","doi":"10.1088/0022-3735/1/11/303","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/303","url":null,"abstract":"A double beam spectrophotometer is described, suitable for the measurements of very low attenuation coefficients in glass in the wavelength range 500-1000 nm. The instrument is shown to have a balance stability of ±1 × 10−5. The systematic errors involved in the use of the long samples required for these measurements are studied. The instrument is shown to be satisfactory in making measurements of attenuation coefficients of 00001 cm−1 with an accuracy to ±0000 01 cm−1 when sample pairs of 20 cm length difference are used. Results of measurements on very low loss silica, which illustrate the performance of the instrument, are given.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/303","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16783109","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 : 1968-11-01DOI: 10.1088/0022-3735/1/11/416
J D Cross, P M Cross
A simple and inexpensive means of studying samples containing water in a scanning electron microscope is described. The sample is maintained at a low temperature by thermal isolation in the specimen chamber. Micrographs of ice and clay with a high water content are presented.
{"title":"Scanning electron microscopy of materials containing water without a refrigerated stage.","authors":"J D Cross, P M Cross","doi":"10.1088/0022-3735/1/11/416","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/416","url":null,"abstract":"A simple and inexpensive means of studying samples containing water in a scanning electron microscope is described. The sample is maintained at a low temperature by thermal isolation in the specimen chamber. Micrographs of ice and clay with a high water content are presented.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/416","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16783113","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 : 1968-11-01DOI: 10.1088/0022-3735/1/11/202
R A Saunders
The methods of measurement of nuclidic mass and isotopic abundance by mass spectroscopy are reviewed. The various factors that limit the accuracy of these measurements are considered. Also studied are those factors that limit the sensitivity of the mass spectroscope. The ways in which mass and abundance measurements are used when a mass spectroscope is used for chemical analyses are discussed and the limitations of the various methods are considered.
{"title":"The limits of measurement with mass spectroscopy.","authors":"R A Saunders","doi":"10.1088/0022-3735/1/11/202","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/202","url":null,"abstract":"The methods of measurement of nuclidic mass and isotopic abundance by mass spectroscopy are reviewed. The various factors that limit the accuracy of these measurements are considered. Also studied are those factors that limit the sensitivity of the mass spectroscope. The ways in which mass and abundance measurements are used when a mass spectroscope is used for chemical analyses are discussed and the limitations of the various methods are considered.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16784431","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 : 1968-11-01DOI: 10.1088/0022-3735/1/11/425
R Isaacson
Field modulation is used with pulsed electron spin resonance apparatus to measure the relaxation time T1 of weak but easily saturable paramagnetic resonances. Both a boxcar integrator and lock-in detector are used to recover the field modulation signal from the noise. The method works best for T1 between about 1 μs and 1/10 of the field modulation period (e.g. approximately 1 ms for 100 cycles) but it may be used to measure longer relaxation times also.
{"title":"Use of field modulation with boxcar integrator to measure relaxation time in electron spin resonance experiments.","authors":"R Isaacson","doi":"10.1088/0022-3735/1/11/425","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/425","url":null,"abstract":"Field modulation is used with pulsed electron spin resonance apparatus to measure the relaxation time T1 of weak but easily saturable paramagnetic resonances. Both a boxcar integrator and lock-in detector are used to recover the field modulation signal from the noise. The method works best for T1 between about 1 μs and 1/10 of the field modulation period (e.g. approximately 1 ms for 100 cycles) but it may be used to measure longer relaxation times also.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/425","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15410983","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 : 1968-11-01DOI: 10.1088/0022-3735/1/11/415
T Ochs
Some simple but adequate methods of orienting and polishing large single crystals for ultrasonic measurements are described. These methods are useful for a variety of materials, particularly for metals and ionic crystals. Included are an x-ray method of measuring orientation and a description of fixtures and procedures involved in polishing. The use of these techniques on low lineage crystals can result in orientation accuracies of less than ½°, flatness of 5 × 10−6 in, and parallelism of 2 seconds of arc with moderate means and effort.
{"title":"Orienting and polishing single crystals for ultrasonic measurements.","authors":"T Ochs","doi":"10.1088/0022-3735/1/11/415","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/415","url":null,"abstract":"Some simple but adequate methods of orienting and polishing large single crystals for ultrasonic measurements are described. These methods are useful for a variety of materials, particularly for metals and ionic crystals. Included are an x-ray method of measuring orientation and a description of fixtures and procedures involved in polishing. The use of these techniques on low lineage crystals can result in orientation accuracies of less than ½°, flatness of 5 × 10−6 in, and parallelism of 2 seconds of arc with moderate means and effort.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16783112","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 : 1968-10-01DOI: 10.1088/0022-3735/1/10/307
B J Legg, K J Parkinson
An infra-red gas analyser, used for differential measurement of carbon dioxide concentrations, has been calibrated both by a pressure difference method and also by absolute concentration differences. The two calibrations differ, and a correction factor for the pressure method has been obtained.
{"title":"Calibration of infra-red gas analysers for use with carbon dioxide.","authors":"B J Legg, K J Parkinson","doi":"10.1088/0022-3735/1/10/307","DOIUrl":"https://doi.org/10.1088/0022-3735/1/10/307","url":null,"abstract":"An infra-red gas analyser, used for differential measurement of carbon dioxide concentrations, has been calibrated both by a pressure difference method and also by absolute concentration differences. The two calibrations differ, and a correction factor for the pressure method has been obtained.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/10/307","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778685","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 : 1968-10-01DOI: 10.1088/0022-3735/1/10/413
F Hillenkamp
A method is described which allows the experimental determination of the heat capacity of laser-cone calorimeters. The method includes the usual calibration with a current pulse applied to the cone's heating coil, and a second calibration with d.c. current. Uncertainties in the calibration of such calorimeters due to possible incomplete heat transfer between the coil, the cone and the temperature sensors are thereby eliminated.
{"title":"On the claibration of laser-cone calorimeters.","authors":"F Hillenkamp","doi":"10.1088/0022-3735/1/10/413","DOIUrl":"https://doi.org/10.1088/0022-3735/1/10/413","url":null,"abstract":"A method is described which allows the experimental determination of the heat capacity of laser-cone calorimeters. The method includes the usual calibration with a current pulse applied to the cone's heating coil, and a second calibration with d.c. current. Uncertainties in the calibration of such calorimeters due to possible incomplete heat transfer between the coil, the cone and the temperature sensors are thereby eliminated.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/10/413","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778688","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 : 1968-10-01DOI: 10.1088/0022-3735/1/10/415
W W Forrest, V A Stephen
A milliwatthourmeter is described which is capable of measuring small d.c. power inputs over a wide dynamic range with an accuracy to ±03%. The maximum power input is 10−2W. The circuit uses plug-in modular components and is designed particularly for use in conjunction with adiabatic microcalorimeters.
{"title":"Analogue circuit for accurate evaluation of small power inputs in microcalorimetry.","authors":"W W Forrest, V A Stephen","doi":"10.1088/0022-3735/1/10/415","DOIUrl":"https://doi.org/10.1088/0022-3735/1/10/415","url":null,"abstract":"A milliwatthourmeter is described which is capable of measuring small d.c. power inputs over a wide dynamic range with an accuracy to ±03%. The maximum power input is 10−2W. The circuit uses plug-in modular components and is designed particularly for use in conjunction with adiabatic microcalorimeters.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/10/415","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778689","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 : 1968-10-01DOI: 10.1088/0022-3735/1/10/312
W W Warren, W G Clark
The description of a furnace for nuclear magnetic resonance experiments between room temperature and 1300°C is given. It is easy to construct, and has an option for control of the atmosphere surrounding the sample or application of a uniaxial stress to the sample. The power requirement for operation at 1000°C is 130 W. Sufficient external cooling is provided by the laboratory environment.
{"title":"Simple furnace for high temperature nuclear magnetic resonance experiments.","authors":"W W Warren, W G Clark","doi":"10.1088/0022-3735/1/10/312","DOIUrl":"https://doi.org/10.1088/0022-3735/1/10/312","url":null,"abstract":"The description of a furnace for nuclear magnetic resonance experiments between room temperature and 1300°C is given. It is easy to construct, and has an option for control of the atmosphere surrounding the sample or application of a uniaxial stress to the sample. The power requirement for operation at 1000°C is 130 W. Sufficient external cooling is provided by the laboratory environment.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/10/312","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778686","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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