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High‐energy background radiation from PBFA II at Sandia National Laboratory introduces uncertainty regarding the effect of background fogging on the sensitivity of the x‐ray film at soft x‐ray energies. We have performed a calibration to determine how the sensitivity of the Kodak RAR 2492 film is affected by high‐energy background radiation. To simulate the background radiation the film was fogged to various densities using a 10 keV bremsstrahlung spectrum. The film was then exposed to soft x‐ray emission lines of Al Kα and Ti Kα selected by Bragg reflection from an electron bombardment source. The intensity of the x‐ray flux was continuously monitored with a Si(Li) detector to eliminate error due to drift of the x‐ray source’s intensity. A microdensitometer with matched objectives was used to find the specular density of the exposed film. The results of the calibration are presented in the form of D vs log l for the various densities of the bremmstrahlung prefog exposures.

The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si(Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this technique to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3keV but has reduced sensitivity a...

The hollow glass or plastic microspheres used as laser targets range in diameter from a few micrometers to several hundred micrometers and can be selected from batches of commercially available microspheres. Preliminary selection of the very few that appear satisfactory for further testing can be accomplished by a practical nondestructive technique based on their refractive properties; when they are transilluminated and viewed through a microscope focused upon the surface upon which they rest, deviations from sphericity and uniform wall thickness appear as deviations from the ideal pattern of a perfectly symmetrical bright circular disk surrounded by a black ring of uniform thickness; wall defects appear as anomalies in this pattern. The method is shown to be soundly based on optical principles and theory. A model of the illumination distribution, including intensity profiles of model microspheres with specified characteristics, is compared with the rigorous measurements necessary for final selection of laser targets. The ratio between the inside diameter of the black ring and the outside diameter of the microsphere is a function of wall thickness, which can be calculated accurately on this basis. The same relationship also permits determination of the density of DT gas in a gas‐filled sphere or the thickness of a layer of solid DT on the inner surface. Either microspheres or their photographs can be rapidly scanned and digitized by a computer‐controlled microdensitometer; data points can be recorded for 1‐μm intervals in the X and Y directions and can be displayed as density contours, density profiles, or isometric density profiles. Another convenient instrument for viewing microspheres as well as for rigorous measurements is a color‐isodensity television system with a microscope attachment.

This paper discusses two characteristics necessary for efficient laser‐induced transfer of organic colorants. Results analyzed on a scanning electron microscope and scanning microdensitometer suggest that the material transfer is caused by melting and vaporization.

The paper presents polycrystalline X-ray diffraction data for three high-pressure phases of InSb. The study employed two types of diamond-anvil pressure cells. The X-ray diffraction parameters were recorded at different fixed pressures and temperatures on flat film. The experiment utilized Zr-filtered Mo radiation. The intensities were estimated from the X-ray photographs using a semiautomated microdensitometer.

Scanning microdensitometers used for astronomical plate scanning in connection with guide star selection for the Space Telescope have had their spatial resolution and accuracy increased by addition of a laser interferometer position measurement system. The standard Perkin–Elmer model 2020 GM PDS microdensitometer has a spatial resolution of 1 μm and an accuracy and repeatability of 5 μm. The addition of a Hewlett–Packard model 5501A Laser Transducer System increases the resolution to approximately 0.6 μm and the accuracy and repeatability to 0.5 μm. Utilization of this increased performance is dependent on the thermal environment of the systems.

Raman spectra are listed for series of acetylenic bromides, iodides, and ketones, and for ascaridole, 1,3‐dioxane, ethyl‐p‐toluenesulfonate, and for the cis‐ and trans−1,2‐diacetoxycyclohexanes. Depolarization factors (when obtained) and relative intensities were measured by use of a Gaertner microdensitometer.

A method for obtaining depolarization factors of Raman lines is described in which a 90°, split‐field Polaroid disk is placed in contact with the window of the Raman tube and is focused upon the slit of the spectrograph by means of a condensing lens. Corrections for real or apparent polarization owing to the spectrograph, reciprocity failure of the plates, and convergence errors are made. The precision of the results was tested by measurements on five different spectrograms of CCl4. The results indicated that the method is equal in precision to the method of Reitz. Intensities were obtained by use of a Gaertner microdensitometer. Depolarization factors for toluene were also obtained. It is shown that, for this method, a reasonable working rule is to regard those Raman lines having observed depolarization factors equal to or greater than 0.78 as depolarized, all others as polarized.

A sensitive integrating microdensitometer for evaluation of diffraction films is reported. The instrument is simple in construction and requires no critical alignment. Contrary to general designs the scanning is done with the receiver by a Vidicon television pickup tube serving both as light sensitive element and scanning device. Circuits for processing the video signal are described.

A microdensitometer is described that has the form of an attachment fitting over the ocular tube of a standard microscope. It periodically scans a stationary object which can be viewed at the same time by the eye. The electrical output of the densitometer is displayed on an oscilloscope screen, with linear or logarithmic readout. Maximum resolution is 1 micron using a 20× N.A.0.5 microscope objective. Measurements can be made of photographic films and of electron beam spots on fluorescent screens without modifying the instrument.

A recording microdensitometer is described that has a resolving power of 800 lines/mm when the scanning aperture is 1 μ wide and 200 μ long. The response is linear in density to 3.0 for the same aperture. By narrowing the aperture to 0.1 μ, the resolving power can be increased to 1800 lines/mm. The record is made either on chart paper with rectangular coordinates, on punched cards, or on both.

The use of photographic emulsions to record the spatial distributions and the intensity of radiation in spectroscopy, x‐ray diffraction, astronomy, and other fields is hampered by the sensitivity of the characteristic curve to development and exposure conditions. The deflection of a microphotometer or microdensitometer of conventional design cannot be made directly proportional to the intensity of radiation which is incident upon the element of area of the film or plate at the time of exposure.The recording microdensitometer described herein incorporates a device, termed a function transformer, which automatically and continuously converts densitometer deflection values to exposure values, and two pen and ink recorders. One recorder produces a direct exposure trace, while the other records the usual densitometer trace. An integrator permits the integrated exposure to be evaluated for any desired portion of the plate or film.The apparatus described can be used with any film or plate to which a suitable cal...

Raman frequencies, relative intensities, and depolarization factors are reported for hexachloroethane and hexabromoethane. The relative intensities and depolarization factors were obtained by use of a Gaertner microdensitometer. The fundamental frequencies of hexachloroethane were used to calculate force constants from the equations used by Stitt for ethane. The Raman data indicate that the equilibrium configuration for hexachloroethane is that corresponding to the point group D3d. The force constants so obtained were then used to calculate the values of the frequencies that are allowed by the selection rules in the infra‐red spectrum. Selection rules for the fundamentals, binary combinations, overtones of non‐degenerate frequencies, and overtones of degenerate frequencies up to the fourth overtone for any molecule whose symmetry is D3h, D′3h, or D3d were worked out and are discussed.

The evaluation of photographic line patterns is discussed with the object of comparing various procedures in their relation to the design of a microdensitometer. While some of the points discussed apply to the evaluation of optical spectra, the main interest of the discussion is directed towards setting out the various requirements which arise in the evaluation of x‐ray patterns. The second part of the paper describes a microdensitometer designed to conform with some of these requirements.

A S‐100/Z80 8‐bit microprocessor‐based system which is used to digitize, reduce, and smooth picosecond data is described. Utilizing real‐time signal sampling combined with a software‐controlled signal averaging, the system uses, to the maximum extent, all of the information obtainable from the microdensitometer. The versatility of the system, in terms of both the hardware and software, minimized the need for extensive in‐house interfacing and makes it possible to scan a film containing six spectra (6×40K raw data points) in 16 min. The use of a LS1 stepping motor controller chip is described.

A technique is described whereby the density of diffraction spots on unidimensional x‐ray film is measured by means of a microdensitometer and recorded on a strip chart recorder; simultaneously, the area under the curve is integrated electronically and the results are displayed on a digital counting device. The data for one structure which has been completed gave a final R value of 0.064.

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors are given for the above named hydrocarbons in the liquid state. The relative intensities and depolarization factors were obtained by use of a Gaertner microdensitometer. The depolarization factors were determined by a well‐tested, single‐exposure method. The previous data have been collected, tabulated, and compared with the present results, and probable values and average deviations are listed.

Autocorrelation functions and spectra of the gas density fluctuations have been obtained from microdensitometer tracings of schlieren photographs of the turbulent wakes behind hypervelocity spheres ⅜ in. in diameter traveling with a velocity of about 8 kft/sec (≅ Mach 8). Schlieren photographs of wakes 100 to 10 000 body diameters behind the spheres at pressures ranging from 10 to 160 mmHg were taken and densitometer tracings from these films were analyzed. The relationship between the statistical properties of the film density and that of the gas density has been derived. The results show that the normalized autocorrelation functions and spectra of the turbulent wake of spheres are independent both of pressure and of position behind the body. Further, to the accuracy of the measurements, the turbulent wake appears to be statistically isotropic and homogeneous, and the three‐dimensional spectrum of the gas density falls off as the 5.5 power of the wavenumber.

The fluorescence spectrum of 1/2% p-terphenyl in toluene was obtained by means of a Hilger medium quartz spectrograph. The solution was contained in a 1 cm. thick quartz absorption cell taped over the spectrograph slit, and fluorescence was excited by a 40 mc. radium source placed next to the cell. The plate was exposed 65 hours and the density measured by a Leeds and Northrup recording microdensitometer.