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Carroll, J. J.

Publications and source records attributed to Carroll, J. J..

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Measurement of the Isolated Nuclear Two-Photon Decay in Ge 72

The nuclear two-photon or double-gamma (2 γ ) decay is a second-order electromagnetic process whereby a nucleus in an excited state emits two gamma rays simultaneously. To be able to directly measure the 2⁢ γ decay rate in the low-energy regime below the electron-positron pair-creation threshold, we combined the isochronous mode of a storage ring with Schottky resonant cavities. The newly developed technique can be applied to isomers with excitation energies down to ~100 keV and half-lives as short as ~10 ms. The half-life for the 2⁢ γ decay of the first-excited 0 + state in bare 72 Ge ions was determined to be 23.9(6) ms, which strongly deviates from expectations.

59 ≤ A ≤ 89↗
NASA NTRS1986

Accuracy of wind measurements using an airborne Doppler lidar

Simulated wind fields and lidar data are used to evaluate two sources of airborne wind measurement error. The system is sensitive to ground speed and track angle errors, with accuracy required of the angle to within 0.2 degrees and of the speed to within 1 knot, if the recovered wind field is to be within five percent of the correct direction and 10 percent of the correct speed. It is found that errors in recovered wind speed and direction are dependent on wind direction relative to the flight path. Recovery of accurate wind fields from nonsimultaneous sampling errors requires that the lidar data be displaced to account for advection so that the intersections are defined by air parcels rather than fixed points in space.

Carroll, J. J.↗
NASA NTRS1985

Airborne Doppler measurements of the central California extended sea breeze

One data acquisition flight was executed in the late summer of 1984. The flight paths were designed to obtain measurements of the extended sea breeze penetration into the central valley of California over several hours. Data from this flight are being processed at Marshall Space Flight Center prior to release for analysis.

Carroll, J. J.↗
NASA NTRS1984

Evaluation of airborne lidar wind measurements

The verification of the Doppler lidar wind measurement is continued. The in situ measurements on a 500 meter tall tower are used to check the lidar determined winds (flight 4), followed by other tests applied to the extensive data sets of flights 19 and 21. After checking for possible software errors in the processing programs, the inconsistency was not solved. The source of the errors appears to be the uncertainty in the calculation of the contribution of the aircraft motion to the lidar measured line of sight speed. Possible techniques for estimating the aircraft motion errors from the aircraft data are investigated.

Carroll, J. J.↗
NASA NTRS1970

Atmospheric vorticity and dust devil rotation

Atmospheric vorticity and dust devil rotation direction relationship, suggesting shear in horizontal flows associated with convective activity in unstable atmosphere

Carroll, J. J.↗