A Method of Measuring Jet Exhaust Density Profiles Using Soft X-Rays

摘要

A new method suitable for measuring the density profile in a jet exhaust has been devised. The method is based on the transport properties of soft X-rays. The use of uncollimated detectors, capable of receiving flux over 2 pi steradians, simplifies the experimental aspects of any application and results in a large reduction in the required source intensity. A general analytic method for predicting the X-ray fluxes reaching the detectors has been developed and tested using Monte-Carlo methods. Methods of using the density profile of a jet exhaust to compute (inflight) gross thrust are treated. It is shown that the gross thrust is nearly linear in the product of exhaust density and total temperature and that the gross thrust has a reasonable sensitivity to exhaust density. (Author)