The Roswell Report: Fact vs. Fiction in the New Mexico Desert

Read from the scan by GLM-OCR; expect the odd misread word.

made on this project. A complete report of these flights and the equipment used is included in "Technical Report 121.01"(6) by this Research Division.

## 2. High Neutron Intensity Study (Contract AF 28(099)-10)

In conjunction with a study to determine the altitude of maximum neutron density a modification was made on the Constant Altitude balloon system developed under this contract. In order to study neutron densities at two different altitudes with the same set of instruments, it was desirable to carry these instruments through a "stepped flight". The balloon system in this case was to ascend to a selected altitude (say 45,000 ft.) float there for one hour and then ascend to a higher altitude (for example 65,000 ft.) to float for another hour before descending.

The advantages of this type flight for Cosmic Ray studies are that a given altitude may be sampled for a long enough period of time to obtain statistically valid results, and such statistical sampling can be made at several levels without the necessity of releasing another balloon system and other set of neutron sensing instruments. By proper design of equipment a fairly wide range of altitudes can be sampled with "altitude steps" of almost any desired size.

The step effect is attained by release of a fairly large amount of ballast at a fast rate set off by a pre-set clock timer or a radio release activated by a transmitter on the ground. The amount of ballast to be released is determined from the standard altitude- volume load relationships used for constant-level balloon flight. As a part of the final ballast release, the ballast tank and its controls may be dropped from the system.

If the level positions of the flight must be controlled to fine limits, or if they must be of long duration (more than two hours) it is necessary to employ constantlevel ballast control over these portions of the flight. However, if the level portions of the flight are to be in the neighborhood of 1 hour duration, ballast control during these floating periods can be eliminated, making use of the inherent stability of the plastic balloon systems for short range constant level flights. It is this latter method which was used by the New York University group in the study of Neutron Maxima.