OPERATION UPSHOT-KNOTHOLE Project 6.12 DETERMINATION OF HEIGHT OF BURST AND GROUND ZERO
The purpose of this series of experiments was to test methods available to the field army for tactical determination of atomic burst location and yield over enemy-held terrain. Preliminary analysis indicated that the systems that should be tested were sound ranging, seismic height of burst determination, photographic flash ranging, and Bhangmeter type systems for yield determination. Sound ranging was accomplished using standard equipment with modified techniques. Microphone arrays of dimensions which were small compared to the range were used to eliminate hyperbolic curvature corrections and to simplify meteorological corrections. A new system of meteorological corrections was employed. This system was based on approximating the maximum height reached "by the sound vhich ultimately passes across the microphone array. It was determined that this technique gave far greater accuracy than conventional techniques at these long ranges. Most accurate locations were obtained on air bursts. For air bursts at ranges from 20,000 to 60,000 meters, angular standard deviations of 13.8 minutes of arc were obtained. For air bursts, the average radial location error expressed as per cent of range was 0.61 per cent. It was estimated that in a tactical situation these locations could he computed in less than 30 minutes. Seismic height of burst determinations were attempted hy the heat seismic and the seismic velocity methods. Both methods depended upon the travel time of the shock wave from the point of origin to ground zero. The heat seismic method used in addition a seismic signal generated hy the heat radiated from the nuclear detonation, as postulated hy earlier investigators. The velocity seismic method utilized additional seismic shocks for a determination of seismic propagation constants. Conclusive evidence as to the feasibility of either seismic method was not obtained. Photographic flash ranging was accomplished using pinhole cameras and Polaroid film. The tactical requirement for speed in processing required the use of this film. The camera used was a modification of an experimental flash ranging camera /part of Flash Ranging Set AN/TVS-1 (XE-2)_7with the conventional refractive optics replaced by a pinhole. A high speed shutter tripped hy a blue box was employed. It was determined experimentally that a given pinhole aperture with a fixed delay time provided photographs of the fireball with adequate resolution for accurate angular measurements over a wide range of yields and distances. Average angular accuracies of 0.73 mils were obtained. It was estimated that ground zero locations and burst heights could be provided by this method under tactical conditions in 5 to 10 minutes. Conventional Bhangpeters furnished yield determinations under non-line-of-sight conditions at ranges out to UO miles with an accuracy of the order of 20 per cent or better. Attempts to utilize a Bhangmeter type instrument with a lead sulfide cell detector indicated that extensive investigation would be required to establish the correlation between yield and time to minimum in the light intensity-time curve for the spectral response of the lead sulfide cell. Attempts to modify a Mark III Type Bhangmeter by substituting a lead sulfide cell for the photo cell made possible successful time of flight measurements on the 260 mm gun when firing conventional ammunition. Design parameters were established for such a time of flight measuring equipment.
- Research Organization:
- Signal Corps Engineering Labs, Fort Monmouth, NJ
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- OSTI ID:
- 1068834
- Report Number(s):
- WT-760
- Country of Publication:
- United States
- Language:
- English
Similar Records
Explosion airblast predictions on a personal computer and application to the Henderson, Nevada, incident. [Air blast or buried]
Technical photography