Pub Date : 1968-06-01DOI: 10.1088/0022-3735/1/6/309
W M Jones, D Maidment, D V Morgan
A prototype direct-reading ionic flowmeter to measure rates of flow of air as low as 0·37 μg S−1 has been constructed. The flowmeter functions best at a pressure of 15 torr. A discharge is struck in the air and the discharge current is fixed at about 50 μA. Two ionization chambers are placed symmetrically in a Perspex tube, one on either side of the discharge. Currents through the ionization chambers are arranged in opposition so that there is a null reading on a Vibron electrometer when there is no air flow. When flow of air does occur some ions are carried out of the upstream ionization chamber while some ions are carried into the downstream chamber; the consequent differential current in the electrometer is about 2 pA when the flow is 0·37 μg s−1. The differential current increases linearly with the rate of flow of air at 6 μA (g s−1)−1 up to rates of flow of about 10 μg s−1; thereafter the relationship between differential current and rate of flow departs from linearity, reaching a maximum at a rate of flow of around 0·1 mg s−1. The behaviour of the flowmeter may best be described by regarding the ions as diffusing from the discharge (without recombination) to the ionization chambers.
{"title":"A simple ionic flowmeter for measuring very small rates of flow of air.","authors":"W M Jones, D Maidment, D V Morgan","doi":"10.1088/0022-3735/1/6/309","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/309","url":null,"abstract":"A prototype direct-reading ionic flowmeter to measure rates of flow of air as low as 0·37 μg S−1 has been constructed. The flowmeter functions best at a pressure of 15 torr. A discharge is struck in the air and the discharge current is fixed at about 50 μA. Two ionization chambers are placed symmetrically in a Perspex tube, one on either side of the discharge. Currents through the ionization chambers are arranged in opposition so that there is a null reading on a Vibron electrometer when there is no air flow. When flow of air does occur some ions are carried out of the upstream ionization chamber while some ions are carried into the downstream chamber; the consequent differential current in the electrometer is about 2 pA when the flow is 0·37 μg s−1. The differential current increases linearly with the rate of flow of air at 6 μA (g s−1)−1 up to rates of flow of about 10 μg s−1; thereafter the relationship between differential current and rate of flow departs from linearity, reaching a maximum at a rate of flow of around 0·1 mg s−1. The behaviour of the flowmeter may best be described by regarding the ions as diffusing from the discharge (without recombination) to the ionization chambers.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/309","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735647","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/304
I J Lowe, C E Tarr
A gated radio-frequency transmitter suitable for pulsed nuclear magnetic resonance spectroscopy is described. It has a wide frequency response (3 dB from about 20-50 MHz) and can deliver pulses of greater than 900 v peak to peak into 180 Ω resistive loads with rise and fall times of less than 01 μs. The circuitry described includes a gated radio-frequency mixer-amplifier with two variable phase inputs, and a gated radio-frequency power amplifier. The gating circuits used are d.c. coupled throughout to prevent droop in long pulses and interaction between the pulses.
{"title":"A high-power, untuned radio-frequency transmitter for pulsed nuclear magnetic resonance spectroscopy.","authors":"I J Lowe, C E Tarr","doi":"10.1088/0022-3735/1/6/304","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/304","url":null,"abstract":"A gated radio-frequency transmitter suitable for pulsed nuclear magnetic resonance spectroscopy is described. It has a wide frequency response (3 dB from about 20-50 MHz) and can deliver pulses of greater than 900 v peak to peak into 180 Ω resistive loads with rise and fall times of less than 01 μs. The circuitry described includes a gated radio-frequency mixer-amplifier with two variable phase inputs, and a gated radio-frequency power amplifier. The gating circuits used are d.c. coupled throughout to prevent droop in long pulses and interaction between the pulses.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735979","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}
{"title":"Performance of a high sensitivity liquid scintillation whole-body counter.","authors":"D H Pringle, C F Barnaby","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735653","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/443
F Akerboom, H H Van Mal
A description is given of a form of mercury manometer which has the measurement arms in line with each other, has a very rigid construction and yet a loss in working range of only 3?5 cm. Where a cathetometer is used and where a large number of accurate readings must be made, such an instrument can save time and effort and can diminish sources of error.
{"title":"An improved form of mercury manometer.","authors":"F Akerboom, H H Van Mal","doi":"10.1088/0022-3735/1/6/443","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/443","url":null,"abstract":"A description is given of a form of mercury manometer which has the measurement arms in line with each other, has a very rigid construction and yet a loss in working range of only 3?5 cm. Where a cathetometer is used and where a large number of accurate readings must be made, such an instrument can save time and effort and can diminish sources of error.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/443","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735654","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/312
J Edwards, B J Brinkworth
A description is given of a device which provides automatic long-term control of the size of aerosol particles produced by the La Mer generator. The control system input signal is derived from the light-scattering properties of the outgoing particles. Over periods of eight hours, variations in mean size are found to be typically less than 10% for aerosols with particle diameters of about 1 μm.
{"title":"A device for the control of particle size in the La Mer aerosol generator.","authors":"J Edwards, B J Brinkworth","doi":"10.1088/0022-3735/1/6/312","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/312","url":null,"abstract":"A description is given of a device which provides automatic long-term control of the size of aerosol particles produced by the La Mer generator. The control system input signal is derived from the light-scattering properties of the outgoing particles. Over periods of eight hours, variations in mean size are found to be typically less than 10% for aerosols with particle diameters of about 1 μm.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/312","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735649","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/201
R C Learner
This year, 1968, is the 50th anniversary of the formation of the Institute of Physics. (The Institute of Physics and The Physical Society was formed from the amalgamation of the two bodies.) In order to celebrate this Jubilee we are publishing a series of articles concerning various aspects of instrumentation over the last 50 years.
{"title":"Spectrograph design, 1918-68.","authors":"R C Learner","doi":"10.1088/0022-3735/1/6/201","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/201","url":null,"abstract":"This year, 1968, is the 50th anniversary of the formation of the Institute of Physics. (The Institute of Physics and The Physical Society was formed from the amalgamation of the two bodies.) In order to celebrate this Jubilee we are publishing a series of articles concerning various aspects of instrumentation over the last 50 years.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15964297","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/311
T D Proctor
The paper describes the use of a continuous-wave helium-neon laser to measure the surface area of small concentrations (< 3000 particles per cm3) of dust particles, of size less than 5 μm, suspended in air. The suspension is passed through a size-selector to remove dust particles greater than 5 μm in size and then into a chamber between one of the laser mirrors and the end of the laser tube. Scattering and absorption of radiation from the cavity by the dust particles causes a change in the amount of radiation reflected back into the laser tube, which in turn produces a reduction in the intensity of the output beam. The relationship between the surface-area concentration of the airborne dust and the change in the output intensity is derived, and experiments with an instrument of this type are described and discussed.
{"title":"A laser technique for the measurement of aerosols.","authors":"T D Proctor","doi":"10.1088/0022-3735/1/6/311","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/311","url":null,"abstract":"The paper describes the use of a continuous-wave helium-neon laser to measure the surface area of small concentrations (< 3000 particles per cm3) of dust particles, of size less than 5 μm, suspended in air. The suspension is passed through a size-selector to remove dust particles greater than 5 μm in size and then into a chamber between one of the laser mirrors and the end of the laser tube. Scattering and absorption of radiation from the cavity by the dust particles causes a change in the amount of radiation reflected back into the laser tube, which in turn produces a reduction in the intensity of the output beam. The relationship between the surface-area concentration of the airborne dust and the change in the output intensity is derived, and experiments with an instrument of this type are described and discussed.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/311","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735648","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/306
J D Emmerson, B E Job
Simple mechanical and electrical modifications to the conventional ion source of an MS9 mass spectrometer have permitted its additional use as a field ionization mass spectrometer, while the original electron impact mode of operation is retained. The combined source may be used in either form without any dismantling of the source or the breaking of the vacuum seals.
{"title":"Field ionization mass spectrometry with a modified MS9 spectrometer.","authors":"J D Emmerson, B E Job","doi":"10.1088/0022-3735/1/6/306","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/306","url":null,"abstract":"Simple mechanical and electrical modifications to the conventional ion source of an MS9 mass spectrometer have permitted its additional use as a field ionization mass spectrometer, while the original electron impact mode of operation is retained. The combined source may be used in either form without any dismantling of the source or the breaking of the vacuum seals.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/306","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735980","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/303
K Anderson
An image intensifier system using a four-stage image intensifier optically coupled to a phosphor screen in the electron microscope is described. The system is shown to be limited by the quantum noise inherent in the electron image. The system can detect images down to 10 fA cm−2 which is at least an order of magnitude better than can be achieved by a fully dark adapted operator viewing the normal fluorescent screen of the microscope.
{"title":"An image intensifier for the electron microscope.","authors":"K Anderson","doi":"10.1088/0022-3735/1/6/303","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/303","url":null,"abstract":"An image intensifier system using a four-stage image intensifier optically coupled to a phosphor screen in the electron microscope is described. The system is shown to be limited by the quantum noise inherent in the electron image. The system can detect images down to 10 fA cm−2 which is at least an order of magnitude better than can be achieved by a fully dark adapted operator viewing the normal fluorescent screen of the microscope.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/303","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735978","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 : 1968-06-01DOI: 10.1088/0022-3735/1/6/319
G Sidenius
The development of an oil manometer with a precise continuous electrical readout of the oil height is described. The principle of measurement is by a hot thin wire partly immersed in the oil. The accuracy of the electrical reading is better than ?0?1 mm of oil, the resolution is better than 0?03 mm of oil and the pressure range can be from 1 mm of oil (about 0?06 torr) up to the practical limit of building oil manometers, about 1000 mm of oil (about 60 torr). It is possible to use the transducer electrode directly as a Pirani gauge with a pressure range from 10?4 to 1 torr. The use of the manometer in a pressure stabilizing system is described.
{"title":"An oil manometer with continuous electrical readout.","authors":"G Sidenius","doi":"10.1088/0022-3735/1/6/319","DOIUrl":"https://doi.org/10.1088/0022-3735/1/6/319","url":null,"abstract":"The development of an oil manometer with a precise continuous electrical readout of the oil height is described. The principle of measurement is by a hot thin wire partly immersed in the oil. The accuracy of the electrical reading is better than ?0?1 mm of oil, the resolution is better than 0?03 mm of oil and the pressure range can be from 1 mm of oil (about 0?06 torr) up to the practical limit of building oil manometers, about 1000 mm of oil (about 60 torr). It is possible to use the transducer electrode directly as a Pirani gauge with a pressure range from 10?4 to 1 torr. The use of the manometer in a pressure stabilizing system is described.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1968-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/6/319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16735651","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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