[ { "id": "authors:68h6x-p7c90", "collection": "authors", "collection_id": "68h6x-p7c90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140629-192312570", "type": "monograph", "title": "The Design, Construction, and Performance of a Magnetic Focusing, Semi-Circular, Low Energy Beta-Ray Spectrometer", "author": [ { "family_name": "Henrikson", "given_name": "H. E.", "clpid": "Henrikson-H-E" }, { "family_name": "DuMond", "given_name": "Jesse W. M.", "clpid": "DuMond-J-W-M" } ], "abstract": "A semi-circular beta-ray spectrometer (Fig. 1) has been constructed\nfor operation between 2 and 120 kev electron energy. This\ninstrument was designed to supplement the ring- focusing beta-ray spectrometer\nwhose lower limit is approximately 25 kev. The 180\u00b0\nspectrometer has an electron trajectory radius of 12 cm. The field is\nproduced by two iron free coils spaced to give a nearly homogeneous\nfield (with some second order focusing) in the region of the electron\ntrajectories . The field current is supplied by a one kw motor- generator\nset. Stabilization is obtained to 2 parts in 10, 000 with a rotating electro- mechanical unit and an electronic servo system. Source and\nGeiger counter window dimensions for a standard resolution of 0 .8% are 0.1 cm x 4 cm. With a 10 \u03bc.g/cm^2 formvar window, transmission is assured\ndown to 2 kev electron energy. A recording potentiometer traces the\ncounting rate vs. electron energy. Several examples of chart recordings\nare reproduced to illustrate the performance of the semi- circular beta-ray\nspectrometer.", "publisher": "Caltech Library", "publication_date": "1956-10" }, { "id": "authors:74ywt-9pa32", "collection": "authors", "collection_id": "74ywt-9pa32", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141104-113749673", "type": "monograph", "title": "Design and Development of an Electronic X-Ray Probe for the Study of Alloys and of the Structure of Metals", "author": [ { "family_name": "DuMond", "given_name": "Jesse W. M.", "clpid": "DuMond-J-W-M" }, { "family_name": "Duwez", "given_name": "Pol", "clpid": "Duwez-P" }, { "family_name": "Wittry", "given_name": "David B.", "clpid": "Wittry-D-B" } ], "abstract": "Progress on the design and development of an\nelectronic x-ray microprobe for quantitative\nand qualitative composition measurements of\nabout 1 cubic micron of the surface of metals\nand alloys is described in this report. The\nprinciple is that first used by Castaing, in\nwhich the metal is subjected to bombardment\nby a finely focused probe of electrons and the\nelements present and their proportions are\ndetermined by an analysis of the frequency and\nintensity of the characteristic x-rays emitted.\nWith the first model of the instrument, it will\nbe possible to study the elements in the ranges\nof atomic numbers 19 through 34 and 50 through\n84. This report omits any theoretical treatment\nof the effects of heat generated in the sample,\nfluorescence radiation, or a detailed discussion\nof the corrections that must be made. These\nmatters will be considered in a later report.", "publisher": "California Institute of Technology", "publication_date": "1954-02" }, { "id": "authors:sndg0-ma351", "collection": "authors", "collection_id": "sndg0-ma351", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140629-201517483", "type": "monograph", "title": "A Point Focusing Monochromator for the Study of Low-Angle X-Ray Diffraction: Determining the Size Distributions of Carbon Blacks and a Precision Determination of the Size of Dow Latex Particles", "author": [ { "family_name": "Shenfil", "given_name": "Leon", "clpid": "Shenfil-L" }, { "family_name": "Danielson", "given_name": "Warren E.", "clpid": "Danielson-W-E" }, { "family_name": "DuMond", "given_name": "Jesse W. M.", "clpid": "DuMond-J-W-M" } ], "abstract": "A point focusing x-ray monochromator was designed and\nconstructed for low angle scattering studies. The anastigmatic\npoint focus is achieved by means of two cylindrically bent\nquartz crystals whose focal circles are mutually perpendicular. The beam, emanating from the copper target of an x-ray tube, is reflected in succession, first from the crystal defining the horizontal focal circle and, second from the crystal defining\nthe vertical focal circle following which it comes to a mono\nchromatic point focus of wavelength 1.537 A (Cu Ko(1). The sample to be studied is placed between the second crystal and the point focus, and the scattered beam is detected by means of a photographic plate placed at the point focus, at right angles to the undeviated beam, the latter being suppressed by means of an absorber.\n\nMathematical analysis, in which a ray was traced through\nthe two crystal system, revealed correctly the shape and size\nof the point focus, and the possibility of reducing the latter\nin size by stopping down the beam emerging from the target.\n\nThe instrument and its lining up procedure is described\nin detail, particularly the latter since the orientation of the two crystals relative to each other and the x-ray tube involve twelve degrees of freedom.\n\nSuggestions for improving the intensity of the instrument\nare made . These consist of (1) substitution of topaz crystals\nfor quartz, (2) use of helium atmosphere instead of air to\nsurround the x-ray beam (3) reorientation of the x-ray tube\nto permit smaller angles of emergence of the beam.\n\nAs a trial run for the instrument, the scattering\npatterns of two kinds of carbon black (good scatterers) were\nobtained from which the average particle sizes and size\ndistributions were calculated.", "publisher": "Caltech Library", "publication_date": "1951-10" } ]