Jon H. Shirley

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We develop a comprehensive approach to the evaluation of the uncertainty of a primary frequency standard. Indirect, model-dependent means are employed for the evaluation of all known biases. This approach leads to a lower combined standard uncertainty (CSU) and leaves frequency measurements under altered conditions as a powerful search technique for unknown(More)
Many high-performance atomic frequency standards, including cesium fountains and most optical standards, operate with pulsed measurements, that is, an atomic sample is prepared for measurement, the measurement is made, and the process is repeated at fixed intervals. By introducing frequency modulation of the excitation coherent with the measurement cycle(More)
We discuss the implications of using high-power microwave tests in a fountain frequency standard to measure the frequency bias resulting from distributed cavity-phase shifts. We develop a theory which shows that the frequency bias from distributed cavity phase depends on the amplitude of the microwave field within the cavity. The dependence leads to the(More)
1 Contribution of NIST, an agency of the US government; not subject to copyright in the United States Abstract Knowledge of the magnetic field is required to determine the quadratic Zeeman bias of a cesium frequency standard. The small magnetic fields (C-field) used in PARCS (PARCS is the primary atomic reference clock in space project), may have sufficient(More)
The case history of a young man with bilateral intralobar sequestrations is presented. The patient underwent bilateral resection of the sequestrations, although only the left side was symptomatic. We have found no previous reports in the literature in which bilateral pulmonary resections were performed for this condition. We present the clinical features(More)
We report idiopathic chylopericardium in a physically active, asymptomatic 29-year-old man. Preoperative diagnosis was made by external cardiac imaging after oral administration of 131-I-labeled triolein. To our knowledge this is the first report of preoperative noninvasive diagnosis of chylopericardium. After open drainage and pericardial biopsy, the(More)
An unusually high association of other primary cancers (9.7%) was found during the analysis of 403 consecutive cases of carcinoma of the lung diagnosed at DGMC between 1960 and 1975. Incidence by stage included 17.3% for Stage I (75 cases) and 16.9% for Stage II (59 cases). Median survival by stage was not adversely affected by the associated malignancy.(More)
In atomic fountain primary frequency standards, the atoms ideally are subjected to microwave fields resonant with the ground-state, hyperfine splitting only during the two pulses of Ramsey's separated oscillatory field measurement scheme. As a practical matter, however, stray microwave fields can be present that shift the frequency of the central Ramsey(More)
The presence of spurious spectral components in the microwave excitation may induce frequency shifts in an atomic fountain frequency standard. We discuss how such shifts behave as a function of power variations of the excitation carrier and in the spur-to-carrier ratio. The discussion here is limited to the case of single-sideband spurs, which are generally(More)