Office of the Historian

116. Memorandum From the Chairman of the Joint Atomic Energy Intelligence Committee (Chamberlain) to the Chairman of the U.S. Intelligence Board (Raborn)1

Washington, undated.

SUBJECT

  • JAEIC Comments on the Report of the Foreign Weapons Evaluation Group Meeting of 27 February 1966
1.
The subject report is attached for your information.2
2.
On 27 February the Foreign Weapons Evaluation Group (Bethe Panel) met to consider recent analysis of a class of Soviet thermonuclear devices with yields in the 3–25 MT range that were tested during the 1961–62 test series. [3–1/2 lines of source text not declassified]
3.
The Joint Atomic Energy Intelligence Committee (JAEIC) agrees in general with the principal findings of the Panel, which are as follows:
a.
[14 lines of source text not declassified]
b.
[11 lines of source text not declassified]
c.
[4–1/2 lines of source text not declassified]
d.
The recent Soviet model studies do not warrant any changes to the previously estimated yield-to-weight ratios of Soviet devices.
4.
JAEIC notes that additional work is underway to consider other design models that might reasonably explain the technical data on these Soviet devices. It is hoped that after further analysis a more definitive statement about the characteristics of these and other Soviet devices may be possible.
Donald F. Chamberlain
  1. Source: Washington National Records Center, OSD/AE Files: FRC 330 69 A 2243, 99 USA–USSR Weapons Evaluation (Bethe). Secret; Restricted Data. An attached March 14 transmittal memorandum from James S. Lay, Executive Secretary of the U.S. Intelligence Board, to its Chairman, mentions, among other things, that this report was not scheduled on the agenda of a USIB meeting unless specifically requested by a Board member before March 21.↩
  2. Not printed; the 5-page report, dated February 28, was signed by Hans A. Bethe, Chairman of the Foreign Weapons Evaluation Group.↩