Operation JANGLE. Nevada Proving Grounds, October - November 1951, Blast and Shock Measurements II.
Abstract
At the time of the JANGLE underground shot the rate of progression of the underground wave was measured. In addition, an attempt was made to record the rate of expansion of the fireball and the point of breakaway of the shock front from the fireball. In obtaining close-in measurements of blast phenomena, recording is difficult because of ionization in cables produced by gamma radiation and electrical differences in potential set up by ground currents produced at the time of detonation. To overcome these difficulties and derive a suitable system, several methods were considered, tested, rejected, or modified, some as late as two weeks before the blast. Some of the methods considered and rejected were (1) the Wiancko accelerometers (variable reluctance type), (2) the closed loop resistance method, and (3) the open switch (light recording) method. The two methods finally decided upon were the normally closed thyratron switch and the normally open thyratron switch. For the first method a diaphragm-actuated switch was developed, the opening of which removed a fixed bias on a thyratron tube, permitting it to conduct. The switch for the second method was basically the same as that for the first except that the action of the diaphragm closed the switch and shorted out the bias on a thyratron tube, causing it to conduct.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1952
- Accession Number
- ADA078577