摘要:

A new sampling concept to convert liquid water to vapor without changes in the deuterium to hydrogen ratio has made possible the construction of an automated mass spectrometer system for determining the deuterium to hydrogen ratio of water samples. The automatic cycle uses an increasing pressure approach to mass spectrometer dosing with excellent suppression of memory effects. Mass‐2 ion abundance is used as the pressure sensor to actuate the single control valve in the automatic cycle, coupled with digital readout of the mass‐3 ion abundance. A precision of ±0.1 ppm at the natural concentration level is achieved with a cycle time of 2 min. The automatic cycle has also been applied to on‐stream gaseous hydrogen analysis with a resulting precision of ±0.1 ppm and a 50 sec cycle time.

ISSN:0034-6748    

DOI:10.1063/1.1684734

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

We describe a geometrically exact procedure for aligning the grating and collimating mirrors of a monochromator with respect to its primary reference, the grating rotation axis. A laser and a spectral lamp are required.

ISSN:0034-6748    

DOI:10.1063/1.1684735

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A liquid nitrogen boil‐off calorimeter has been developed and utilized for surface energy measurements. The calorimeter is an all metal, multiwalled chamber which incorporates a means of precisely manostating the calorimetric fluid. The calorimeter also incorporates means for reducing the background pressures in the reaction vessel to 10−8Torr. This calorimeter was designed to accept heat inputs in the range from 50 to 200 J. An achieved measurement precision of 0.05% in energy permits discrimination of small differences in energy states of the reactions occurring within the calorimeter. The calorimeter has been used to determine the surface energy of a metal film formed by evaporation from a wire.

ISSN:0034-6748    

DOI:10.1063/1.1684736

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

An x‐ray macroprobe attachment for the focusing CGR Cristallobloc 31 x‐ray spectrometer has been developed. Selected‐area analysis in the range 0.01–1 mm2has been achieved using electron excitation. Focusing devices giving rectangular spot sizes of 1×1 mm and 2×0.15 mm have been used, and devices for sizes 0.2×0.2 mm and 0.1×0.1 mm should be feasible. All elements down to atomic number 5 (boron) can in principle be analyzed by this inexpensive device. Limits of detection of several elements in different matrices are reported. Applications to several metallurgical problems showing the versatility of the macroprobe are reported (examination of a welded joint and detection of silicon and niobium inclusions).

ISSN:0034-6748    

DOI:10.1063/1.1684737

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A portable dust particle counting and size analyzing instrument with immediate readout would enable number‐vs‐size distributions of airborne particulate matter to be made known quickly in locations difficult of access, such as underground mines. This device operates on the principle of light scattering by individual particles. Battery operation, solid state circuitry, and miniaturized optical design allow the entire instrument to be housed in a briefcase. Total weight is less than 7 kg and over‐all dimensions are 43×33×20 cm. The shaping of the hole edges and conduits and the location of critical flow channels within the photometer head permit stable flow of aerosol past the light field volume where light scattering takes place. A photomultiplier tube receives the pulses of scattered light. The resulting current pulses, height discriminated and continuously integrated, activate milliammeters representing particular (adjustable) size ranges and calibrated in numbers of particles per cubic centimeter.

ISSN:0034-6748    

DOI:10.1063/1.1684738

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A detailed description of a 10.16 cm gas gun that has been designed and installed at Washington State University is presented. The design velocity is 1.5 mm/&mgr;sec; the maximum velocity achieved to date is 0.9 mm/&mgr;sec with an 1100 g projectile. Angular misorientation of the projectile with respect to the target surface is consistently below 0.5 mrad. Brief descriptions of ancillary instrumentation and equipment are also given.

ISSN:0034-6748    

DOI:10.1063/1.1684739

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

A solid state temperature controller is described which is capable of maintaining constant temperature within ±10−6K at 1 K. The circuit is self‐contained and has been used with carbon and germanium resistance thermometers over the range from about 15 to 0.03 K. Bridge balance and heater current are metered, and monitor outputs are included for an oscilloscope display and a strip chart recorder. The bridge circuit is a unique configuration which allows fully guarded cables to the thermometer and higher frequency operation (500 Hz). The control circuit is dual action with separately adjustable integral and linear proportional feedback. Up to 200 mW of control power is available.

ISSN:0034-6748    

DOI:10.1063/1.1684740

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

The x‐ray diffraction characteristics of potassium acid phthalate (KAP) crystals have been measured with a vacuum two‐crystal x‐ray spectrometer using a flowing‐gas proportional counter as a detector. The values of resolving power, percent reflection, and coefficient of reflection as determined from the (1, −1) position rocking curves are reported for the wavelengths between 1.54 Å (Cu K&agr;) and 23.7 Å (O K&agr;). These crystals offer spectral resolving powers from 2000 to 4000 and from 3 to 40% reflection in the soft x‐ray wavelength region. On the basis of these measurements, the crystals will serve as suitable diffracting elements in that range.

ISSN:0034-6748    

DOI:10.1063/1.1684684

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

Apparatus is described which has been developed to photograph the development of simultaneous nuclear electromagnetic cascades in an ionization spectrometer. Light is emitted by the cascades as they pass through layers of plastic scintillator within the spectrometer. This light is imaged onto the photocathode of a four‐stage cascade‐type image intensifier with magnetic focusing. When suitable events occur within the spectrometer the intensifier is pulsed so as to transmit and intensify the stored image. The output screen of the intensifier is then photographed. Two optical systems and image intensifier cameras are used so as to obtain right angle stereoscopy of the cascades.

ISSN:0034-6748    

DOI:10.1063/1.1684685

出版商:AIP    

年代:1970

数据来源: AIP

摘要:

An ion accelerator is described that delivers magnetically separated ion currents of 0.1–20 &mgr;A at 5 eV–10 keV energy into targets of 5 mm2. An electrostatic decelerator in front of the target permits continuous lowering of the ion energy to ca. 5 eV. The accelerator has been used mainly for the production of14C+ion beams from14CO2for the study of the hot atom chemistry of carbon in solid benzene. The ion source is of all metal construction and is a straight capillary arc type. It delivers C+currents of approximately 2 &mgr;A, obtained at 0.2–0.5% efficiency from the14CO2source gas.

ISSN:0034-6748    

DOI:10.1063/1.1684686

出版商:AIP    

年代:1970

数据来源: AIP