Filming seismograms and related materials at the California Institute of Technology

As part of a world-wide effort to create an international earthquake data bank, Caltech's seismology archive has been organized, labeled, described, and microfilmed. It includes a wide variety of original records, documents, and printed materials relating to local and distant earthquakes. At present, we are filming significant seismograms prior to 1963; more than 50,000 records written between 1924 and 1935 have been filmed to date. Seismograms are the principal source of information about earthquakes and the earth's interior. These records, housed at Kresge Laboratory, the headquarters for Caltech's seismological network of stations, are important because they span so much of the period for which instrumental data exists. The early history of the Laboratory points up the role technology has played in the advancement of the science

A dynamic new look at the lambda transition

We discuss aspects of the theory of critical phenomena and explore the superfluid transition in 4He. We review some of the recent experimental and theoretical work on helium in nonequilibrium conditions and summarize some future space experiments that might shed light on disagreements between theory and experiment

The origins of nuclear astrophysics at Caltech

Shortly before the start of World War II, several theoretical physicists, including Hans Bethe and Carl von Weizsacker, advanced the idea that the sun derives it energy from nuclear reactions within its core. C. C. Lauritsen and William Fowler, nuclear physicists at Caltech's Kellogg Laboratory, were among the first experimentalists to appreciate the application of nuclear physics to stellar interiors. Post-war strategies for studying nuclear processes in the stars included an innovative series of unofficial, weekly seminars with Mt. Wilson astronomers at director Ira Bowen's house, the testing of Bethe's carbon cycle in Kellogg, and the collaboration with a diverse group of scientists ranging from cosmologist Fred Hoyle to astronomers Margaret and Geoffrey Burbidge. The events leading up to the publication of the 1957 paper by Fowler, Hoyle, Burbidge, and Burbidge, in The Reviews of Modern Physics, now regarded as a watershed in the history of nuclear astrophysics, are discussed. For his work in low-energy nuclear astrophysics, Fowler won the 1983 Nobel Prize in physics

Probing the helium-graphite interaction

Two separate lines of investigation have recently converged to produce a highly detailed picture of the behavior of helium atoms physisorbed on graphite basal plane surfaces. Atomic beam scattering experiments on single crystals have yielded accurate values for the binding energies of several· states for both (^4)He and (^3)He, as well as matrix elements of the largest Fourier component of the periodic part of the interaction potential. From these data, a complete three-dimensional description of the potential has been constructed, and the energy band structure of a helium atom moving in this potential calculated. At the same time, accurate thermodynamic measurements were made on submonolayer helium films adsorbed on Grafoil. The binding energy and low-coverage specific heat deduced from these measurements are in excellent agreement with those calculated from the band structures

Alfred Nobel, The Loneliest Millionaire

by Michael Evlanoff and Marjorie Fluo

Experiments on Quantum and Thermal Desorption from ^4He Films

Desorption of He atoms from thin films may be resolved experimentally into quantum and thermal components. We show that quantum desorption becomes the dominant part of the signal in submonolayer films. We also show that, when all effects of collisions between desorbed atoms are eliminated, quantum desorption is not focused normal to the surface of optically polished sapphire crystals

Filming seismograms and related materials at the California Institute of Technology

As part of the worldwide effort to create an international earthquake data bank, the seismology archive of the California Institute of Technology (Caltech) has been organized, labeled, described, and microfilmed. It includes a wide variety of original records, documents, and printed materials relating to local and distant earthquakes. The single largest and most complex component of the task has been the preparation and microfilming of Caltech's vast collection of original seismograms. The original proposal envisioned a modest project in which a selected number of seismographic records at Caltech could be made more generally available to the scientific community. These single‐copy records are stored at Kresge Laboratory and comprise thousands of individual photographic sheets, each 30×92 cm. In the end, we microfilmed both the Pasadena station records and those written at the six original stations in the Caltech network. This task got underway in June 1981 and was completed in January 1985. In the course of the project, the staff sorted, arranged, inventoried, copied, and refiled more than 276,000 records written between January 10, 1923 and December 31, 1962. The microfilm edition of the earthquake records at the Seismological Laboratory at Pasadena and at auxiliary stations at Mount Wilson, Riverside, Santa Barbara, La Jolla, Tinemaha, and Haiwee (the latter two in the Owens Valley) consists of 461 reels of film. The film archive is cataloged and available to researchers in Caltech's Millikan Library in Pasadena, at the U.S. Geological Survey in Menlo Park, Calif, and at the World Data Center (National Oceanic and Atmospheric Administration) in Boulder, Colo

Measurement of the SOC State Specific Heat in ^4He

When a heat flux Q is applied downward through a sample of liquid 4He near the lambda transition, the helium self organizes such that the gradient in temperature matches the gravity induced gradient in Tlambda. All the helium in the sample is then at the same reduced temperature tSOC = ((T[sub SOC] - T[sub lambda])/T[sub lambda]) and the helium is said to be in the Self-Organized Critical (SOC) state. We have made preliminary measurements of the 4He SOC state specific heat, C[del]T(T(Q)). Despite having a cell height of 2.54 cm, our results show no difference between C[del]T and the zero-gravity 4He specific heat results of the Lambda Point Experiment (LPE) [J.A. Lipa et al., Phys. Rev. B, 68, 174518 (2003)] over the range 250 to 450 nK below the transition. There is no gravity rounding because the entire sample is at the same reduced temperature tSOC(Q). Closer to Tlambda the SOC specific heat falls slightly below LPE, reaching a maximum at approximately 50 nK below Tlambda, in agreement with theoretical predictions [R. Haussmann, Phys. Rev. B, 60, 12349 (1999)]