A precision bent-crystal gamma-ray monochromator with stationary source has been built. The instrument consists of three physically independent units: The line source (a radioactive source or the anode of an x-ray tube), the two-meter-radius bent-diffraction-crystal with its pivot and sine-motion mechanism, and the heavy-duty curved-track framework which supports the collimator, detector, and shielding. The motions of the crystal-pivot unit and of the detector-carriage unit are linked together in such a way that the reflection condition is satisfied. Results are presented showing that the precision of the monochromator for measurement of gamma-ray wavelengths is 0.003 x-units. The line width at half-maximum observed when the (800) planes of a bent germanium-crystal are used is 0.080 x-units. The resolution which has been attained with the germanium crystal is illustrated by a measurement of the 244.264 kev, 246.056 kev, and the previously unobserved 245.237 kev gamma line in the decay of W^(183). Nuclear-resonance scattering from the first-excited states in F^(19) and Mn^(55) has been observed with the bent-diffraction-crystal monochromator. The experiment was performed by observing the scattered radiation from nuclei exposed to nearly monoenergetic x-rays selected by crystal diffraction from the bremsstrahlung spectrum of an x-ray tube. Gamma rays scattered at 135° from samples of lithium fluoride and manganese placed in the diffracted beam were observed as a function of the incident photon wavelength. With the lithium fluoride sample three measurements were made under different experimental conditions. In each case pronounced resonance peaks 10 to 15 percent above background were observed. A least-square analysis of the data gives 109.894 ± 0.005 kev for the energy position of the first-excited level in F^(19). From the observed yield the width of this level was deduced to be (5.1 ± 0.7)10^(-7) ev. Measurements with a Mn^(55) scattering sample gave 125.95 ± 0.01 kev for the position of the first-excited level and (1.1 ± 0.3)10^(-6) ev for the resonance width.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/9RT5-FA08, author = {Muir, Arthur H.}, title = {An investigation of the Ta181 nucleus}, school = {California Institute of Technology}, year = {1960}, doi = {10.7907/9RT5-FA08}, url = {https://resolver.caltech.edu/CaltechETD:etd-08152006-090808}, abstract = {The nuclear levels of Ta181 were investigated by the study of the [beta]-decay of Hf181 and the electron capture decay of W181. The previously reported 476 kev transition from the Hf181 decay was found not to be in coincidence with the 482 kev transition, thus ruling out the level proposed at 958 kev. Evidence for weak M-shell conversion lines of a ~6 kev transition in the Hf181 decay was found with a 180° [beta]-spectrometer. A [beta]-spectrometer investigation of the W181 decay revealed strong M-shell conversion lines which correspond to a transition of 6.25 ± 0.3 kev in energy. On the basis of the above mentioned results and other considerations, it is concluded that the 476 kev transition in the Hf181 decay occurs between the 482 kev level and the new 6 kev level. A 6 kev [gamma]-ray was also found in the W181 decay with an argon proportional counter. From these studies, the conversion coefficient of the 6 kev transition was determined to be [alpha]T = 44 ± 7. The conversion coefficient and the M-subshell conversion ratios require that the 6 kev transition is of El multipolarity. From this assignment and other experimental and theoretical considerations, it is concluded that the 6 kev level is the 9/2 - [514] Nilsson intrinsic state. Arguments can also be made that the previously reported 152 kev transition in the W181 decay occurs between a new 11/2- rotational level at 158 kev and the 6 kev level. From a measurement of the tantalum L/K x-ray intensity ratio, the W181 electron capture L/K branching ratio (to the ground state and the 6 kev level) is found to be PL/PK = 0.359, and the W181 decay energy is found to be 176(+44)(-22) kev. The branchings of this decay to the various Ta181 levels are as follows: 158 kev (0.12%), 136 kev (0.075%), 6.25 kev (~35%), and 0 kev (~65%). All findings and proposals are consistent with the unified model of the nucleus.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {Boehm, Felix H. and DuMond, Jesse William Monroe}, } @phdthesis{10.7907/85TX-DX83, author = {Dibble, William Edwin}, title = {Design and construction of a point-focusing Berreman type single crystal x-ray monochromator and its application to low-angle scattering studies of biological specimens}, school = {California Institute of Technology}, year = {1960}, doi = {10.7907/85TX-DX83}, url = {https://resolver.caltech.edu/CaltechETD:etd-02172006-154237}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document.
The design and construction of a point-focusing Berreman type, single quartz crystal X-ray monochromator is described. Monochromatization and point focusing of the copper […] line are obtained by Bragg reflection from the surface of a 2 1/2 by 2 3/8 by 0.015 in. curved crystal lamina which has been subjected to two successive cylindrical bendings at right angles to each other. With a 0.0225 in. aperture defining the size of the X-ray source next to a General Electric CA-7 diffraction tube running at 45 KV and 18 ma, about 3 x 10(9) counts per minute as determined by Geiger tube measurements may be put into a 0.025 half width focus, with the beam in helium atmosphere. Parasitic scattering from the crystal had to be excluded by using a converging vane collimator, which required coating with lead chloride to prevent low-angle total reflection from the vanes. Sample-to-detector distances of up to 49 cm are obtainable. Both photographic and counter detection are used.
Scattering patterns obtained with the instrument on samples of rabbit reticulocyte ribosomes are interpreted to determine the radius of gyration of the particles of 105 A to 2 per cent and the molecular weight of 4.1 x 10(6) to about twenty per cent. No evidence of secondary scattering maxima was observed. The electron density of the sample is approximated by a Gaussian consistent with the data with a cutoff at 170 A, giving in connection with electron microscope data of Professor Hall a hydration of 2.7 g water per g ribosome.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/RCBJ-T737, author = {Edwards, William Farrell}, title = {Experimental studies of conversion coefficients in some deformed nuclei}, school = {California Institute of Technology}, year = {1960}, doi = {10.7907/RCBJ-T737}, url = {https://resolver.caltech.edu/CaltechETD:etd-10042005-102708}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document.
The Mark I curved-crystal spectrometer at the California Institute of Technology was calibrated for intensity measurements. The predominant correction to the relative intensities is due to the energy dependent reflectivity of the curved quartz crystal which was found to vary as […] over the energy range 60 kev […] 400 kev.
Conversion coefficients and energies of transitions in the following deformed nuclei were measured: […], […], […], and […]. Three E1 transitions with anomalous conversion coefficients were studied. The […], […], and M coefficients of the K-forbidden 57.54-kev transition in […] were found to be 0.458 ± 0.036, 0.084 ± 0.012, and 0.134 ± 0.015 respectively as compared with the theoretical E1 values of Rose (6) of 0.163, 0.062, and 0.086. The anomalous nature of the 152.41-kev transition in […] is confirmed with the present value of the K-conversion coefficient of 0.05. The theoretical E1 value is 0.11. The K-conversion coefficient of the 72.00-kev transition in […] is […] whereas the theoretical E1 value is 0.52. This anomaly might be explained by the fact that the transition energy differs from the K binding energy by only 0.34 kev.
The four E2 transitions in […] show slight deviation from the theory. With the exception of the 93.33-kev transition the K-conversion coefficients are all about 10% low. Furthermore, with respect to the theoretical values, the L coefficients seem to follow a fairly smooth curve, decreasing as a function of energy and having a maximum deviation from the theoretical values of 12%.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/81EA-4141, author = {Merrill, John J.}, title = {Precision measurement of x-ray spectra with application to the L x-ray spectra of uranium, neptunium, plutonium, and americum}, school = {California Institute of Technology}, year = {1960}, doi = {10.7907/81EA-4141}, url = {https://resolver.caltech.edu/CaltechETD:etd-06272006-131143}, abstract = {Techniques for the precision measurement of X-ray lines using the two-crystal spectrometer are discussed, and then applied to measurement of the L X-ray spectra of the trans-uranic elements uranium, neptunium, plutonium and americium. In all, 52 emission lines and 4 L(III) absorption edges were measured, all of them with higher precision than has heretofore been obtained and many of them for the first time. Using these data, the binding energies of the electrons for these atoms were computed. The L(II)-L(III) level splitting was computed and compared with theory and it was found that current theory is not sufficient to account quantitatively for the observed data. Certain features of the emission line widths are discussed and given qualitative explanations in terms of the Coster-Kronig transition L(II)-L(III)M(V) and hyperfine structure. The observed hyperfine structure is due to the large magnetic moment of Np237 which leads to increased widths of certain of the Np lines. It is believed that this is the first experimental observation of hyperfine structure in X-ray spectra.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/7J8Y-CY63, author = {Wittry, D. B.}, title = {An electron probe for local analysis by means of x-rays}, school = {California Institute of Technology}, year = {1957}, doi = {10.7907/7J8Y-CY63}, url = {https://resolver.caltech.edu/CaltechETD:etd-09152004-143529}, abstract = {No Abstract Submitted}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/2YQG-G079, author = {Shacklett, Robert Lee}, title = {A precision measurement of the LII-LIII x-ray energy level difference in some heavy elements and a comparison with the predictions of the Schawlow-Townes theory of the nuclear size effect}, school = {California Institute of Technology}, year = {1956}, doi = {10.7907/2YQG-G079}, url = {https://resolver.caltech.edu/CaltechETD:etd-06252004-140127}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document.
The recent experimental determinations of the radius of the nuclear charge distribution all tend to give an approximate value of […] with […]. However, the theoretical work of Schawlow and Townes on the effect of the finite nuclear size on the […] X-ray level splitting, through a comparison with already existing X-ray data, yielded a value of […]. This thesis describes an experimental determination of the […] splitting for six of the heavy elements based on two-crystal spectrometer measurements of the Bragg angles of the […] and […] X-ray lines of W, Pt, Bi, Th, U, and Pu. The Bragg angles of these lines, corrected for vertical divergence, temperature, and crystal diffraction pattern asymmetry, are reported with a mean standard deviation of about 0.2 second of arc. The values of the […] splitting calculated from the wavelengths of the lines have a relative accuracy of about 50 parts per million. When the experimental splittings are compared to the theoretical values which include the nuclear size effect, a value of […] is obtained. The suggestion is made that inaccuracies in the previous measurements of the […] wavelengths for several high Z elements might have contributed to the large value of […] obtained by Schawlow and Townes. When the theoretical splitting is calculated with corrections for vacuum polarization and a nuclear radius constant of […], a comparison with experiment shows that a discrepancy remains which is then used to evaluate an empirical correction term. The sign, magnitude, and Z-dependence of this term suggest that the remaining discrepancy might arise from the Lamb shift effect.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/9485-Z897, author = {Hatch, Eastman Nibley}, title = {Nuclear energy levels in tulium-169 and lutetium-175}, school = {California Institute of Technology}, year = {1956}, doi = {10.7907/9485-Z897}, url = {https://resolver.caltech.edu/CaltechETD:etd-03232004-135248}, abstract = {The electron-capture decay of Yb169 to Tm169 and the beta-decay of Yb175 to Lu175 have been studied using the curved-crystal gamma-ray diffraction spectrometer, the ring-focusing beta-ray spectrometer, and the semicircular homogeneous-field beta-ray spectrometer. The precision energies and the multipolarities of Tm169 and Lu175 nuclear transitions have been determined, and energies, spins and parities of the nuclear levels are proposed. The principal experimental techniques are reviewed, and the results of preliminary measurements of the curved-crystal spectrometer reflection coefficient are indicated. The observed nuclear levels and transitions in Tm169 and Lu175 are discussed on the basis of the Bohr-Mottelson unified nuclear model.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/26VA-RB25, author = {Baggerly, Leo Lon}, title = {The radioactive decay of iridium-92}, school = {California Institute of Technology}, year = {1956}, doi = {10.7907/26VA-RB25}, url = {https://resolver.caltech.edu/CaltechETD:etd-02252004-104516}, abstract = {A study has been made of the gamma radiation following the decay of Ir192. The energies, internal conversion coefficients and multipolarities of the gamma transitions have been determined. Energy level schemes for the daughter nuclei, Pt192 and Os192, are proposed. The spins and parities of most of the levels are given. Some of the regularities found in heavy even-even nuclei have been confirmed for this decay.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/ZGBJ-MY29, author = {Murray, Joseph Jackson}, title = {The decay of Ta183}, school = {California Institute of Technology}, year = {1954}, doi = {10.7907/ZGBJ-MY29}, url = {https://resolver.caltech.edu/CaltechETD:etd-01262004-140923}, abstract = {NOTE: Text or symbols not renderable in plain ASCII are indicated by […]. Abstract is included in .pdf document.
The […] decay of Ta183 into an excited state of W183 has been observed using the curved crystal gamma-ray diffraction spectrometer and the axial focusing homogeneous field beta spectrometer. A unique decay scheme is presented for this mode of excitation of W183 constructed on the basis of the energies and conversion properties of twenty-seven gamma transitions with spin and parity assigned to each level. The principal features of the scheme are no parity change throughout, frequent violation of single particle selection rules, and several examples of competition between E2 and M1 transitions. These results provide amplification of and correction. to preliminary results reported earlier (Dumond, Hoyt, Marmier and Murray, Phys. Rev. 92, 202 (1953)).
In addition to the primary results above, there will also be found a comparison of the experimental and theoretical K and L conversion coefficients for E2 and M1 transitions in the energy range from 40 to 350 kev and experimental M and N conversion coefficients for a few low energy E2 and M1 transitions.
There is presented a review of the techniques employed and of important parts of the analysis of the experimental data especially with regard to corrections applied to observed intensities of gamma and conversion lines. A brief discussion offers a suggestion for possible interpretation of certain aspects of the results in terms of current ideas about, nuclear structure.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/7A7G-7081, author = {Danielson, Warren Evald}, title = {Application of the Point Focusing X-Ray Monochromator to the Study of Low Angle Diffraction}, school = {California Institute of Technology}, year = {1952}, doi = {10.7907/7A7G-7081}, url = {https://resolver.caltech.edu/CaltechTHESIS:09262017-162449067}, abstract = {The geometry of the point focusing monochromator is described, and the instrument’s uses in connection with low angle diffraction studies are outlined. A careful determination of the particle size of latex spheres by studies of the associated low angle diffraction pattern is made, and an experiment to determine the sensitivity of this particle size to external pressure is described. The results of an experiment in which the monochromator is used to obtain important information on the existence and nature of the collagen molecule are given. A technique for finding the size of particles whose shape is reasonably approximated by two spheroids is given, and the technique is applied to the size determination of bacteriophage type T-4. Improvements in the instrument are discussed and several suggestions for further applications are mentioned.}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/9ZRJ-X525, author = {Shenfil, Leon}, title = {Point Focusing X-Ray Monochromator for Low Angle Scattering Studies}, school = {California Institute of Technology}, year = {1952}, doi = {10.7907/9ZRJ-X525}, url = {https://resolver.caltech.edu/CaltechTHESIS:11202017-145724629}, abstract = {A point focusing x-ray monochromator was designed and constructed for low angle scattering studies. The anastigmatic point focus is achieved by means of two cylindrically bent quartz 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 the vertical focal circle following which it comes to a monochromatic point focus of wavelength 1.537 Å (Cu Kα1). 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.
Mathematical analysis, in which a ray was traced through the two crystal system, revealed correctly the shape and size of the point focus, and the possibility of reducing the latter in size by stopping down the beam emerging from the target.
The instrument and its lining up procedure is described in 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.
Suggestions for improving the intensity of the instrument are made. These consist of (1) substitution of topaz crystals for quartz, (2) use of helium atmosphere instead of air to surround the x-ray beam (3) reorientation of the x-ray tube to permit smaller angles of emergence of the beam.
As a trial run for the instrument, the scattering patterns of two kinds of carbon black (good scatterers) were obtained from which the average particle sizes and size distributions were calculated.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/DY6H-6607, author = {Hoyt, Harry Charles}, title = {Precision Wavelength Measurements of the Annihilation Radiation from Copper 64 and Gamma-Radiation Following Decay of Gold 198 and Tantalum 182}, school = {California Institute of Technology}, year = {1952}, doi = {10.7907/DY6H-6607}, url = {https://resolver.caltech.edu/CaltechTHESIS:10112017-100346458}, abstract = {The geometry, kinematics, and operation of the curved crystal gamma-ray spectrometer are briefly described. The effect of a recently discovered systematic non-linearity is discussed in some detail. A new calibration of the instrument and the means taken to correct for the non-linearity are described. Error-contributing factors are analyzed, and their contributions to the final error are estimated. The three principal components of the observed line profile are discussed.
A new measurement of the annihilation radiation is reported. The relation of this measurement to the determination of the mass of the positron is discussed. Measurements of the wavelength of the 411 Kev gamma-ray line following decay of Au198 are given. Wavelengths of sixteen gamma-ray lines following decay of Ta182 are tabulated. The formulation of an energy level scheme for its daughter W182 is discussed.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/H0QJ-YJ54, author = {Felt, Gaelen Lee}, title = {A Measurement of the Value of h/e by the Determination of the Short Wavelength Limit of the Continuous X-Ray Spectrum at 25 Kilovolts}, school = {California Institute of Technology}, year = {1951}, doi = {10.7907/H0QJ-YJ54}, url = {https://resolver.caltech.edu/CaltechTHESIS:10172017-084702172}, abstract = {The apparatus used in the experiment is described in detail and the calibration of the instruments is discussed. The procedure followed in the experiment is described. Experimental results are presented in the form of curves and the analysis of the curves is given in detail. The final value of the ratio h/e obtained in this experiment is
h/e = 1.37912 ± 0.00007 x 10-17erg-sec/esu
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, } @phdthesis{10.7907/SB6A-0Z19, author = {Muller, David Eugene}, title = {A Precision Measurement of the Wavelengths of Gamma and X-Radiation Following Decay of Iridium 192 and Tungsten 187, by Means of the Focusing Crystal Diffraction Spectrometer}, school = {California Institute of Technology}, year = {1951}, doi = {10.7907/SB6A-0Z19}, url = {https://resolver.caltech.edu/CaltechTHESIS:10022017-160139639}, abstract = {Precision determinations of gamma ray and x-ray wavelengths in the spectra following decay of iridium 192 and tungsten 187 are recorded. Measurements of these wavelengths were made with the focusing crystal diffraction spectrometer.
Development of a scintillation counter for use as a gamma ray detector in the spectrometer is described.
The precision of measurements with spectrometer is analyzed; particular attention being paid to errors resulting from statistical variations in counting rate. Linearity of the instrument is studied by comparing measurements obtained with first, second and third order reflections in the crystal.
Gamma ray energies are combined so as to form decay schemes for iridium 192 and tungsten 187.
}, address = {1200 East California Boulevard, Pasadena, California 91125}, advisor = {DuMond, Jesse William Monroe}, }