Dark Sun: The Making Of The Hydrogen Bomb

20

Gouzenko had reported the “assistant secretary” without knowing who he was, but the cipher clerk's account started the investigation that later pointed to Alger Hiss, special assistant to US Secretary of State Edward Stettinius at Yalta. — RR

21

Uranium at low percentages is ubiquitous in the earth's crust, which is why so many houses have radon in their basements — radon, a gaseous product of the radioactive decay of uranium, seeps from stone foundations.

22

Churchill's visit coincided with a sea change in US attitudes. “When the war ended in the summer of 1945,” notes historian John P. Rossi, “60 percent of the American people polled expressed confidence about cooperation between Russia and the Western Allies. By February 1946, on the eve of Churchill's speech, that figure had dropped to 35 percent.” Rossi (1986), p. 117.

23

Heisenberg refused, saying, “The fox notices that many tracks lead into the cave of the bear, but that none come out.” Quoted in Walker (1989), p. 184.

24

Gold does not explain why he and Yakovlev were meeting or what assignment he was supposed to be careful about. — RR

25

The American source of this espionage information has never been identified. The chemistry of uranium and plutonium resembles that of the rare earths — the elements in the periodic table from cerium (58) through lutetium (71). — RR

26

“It is known, for example, that the USSR electronics industry during the [Second World War] was incapable of standardizing such items as vacuum tubes to the extent that spares and replacements could be used interchangeably. It is doubtful that they could have overcome all such difficulties since the war.” JCS 1952,1, 21.XII.48, appendix, p. 11, in Ross and Rosenberg (1989), n.p.

27

The original, from Poltava, went:

Kochubei is rich and famous,

His fields vast and boundless;

Herds of his horses

Graze there, free and unguarded.

28

Probably in response to Bentley's revelations, one of Julius Rosenberg's associates, the engineer Joel Barr, abruptly left the United States for Europe in 1947. In 1949, Barr defected to the Soviet Union, where as lozef Veniaminovich Berg he became chief engineer of the Leningrad Institute of Semiconductors, cf Kuchment (1985).

29

As chairman of the General Advisory Committee to the AEC, Robert Oppenheimer knew how few bombs the US had stockpiled. The fact that Stalin fielded two million men to oppose what he believed to be a plentiful US stockpile is clear evidence, if any is required, that Oppenheimer was not a Soviet spy, as J. Edgar Hoover believed and as retired KGB general Pavel Sudoplatov has alleged.

30

The 1946 Gurevich, Zeldovich, Pomeranchuk and Khariton paper Utilization of the nuclear energy of the light elements discussed using “uranium charges of increased sizes and of a special shape (cumulation) and [introducing] into the deuterium heavy elements near the initiator which might be capable of receiving the radiation pulse.” Although this description sounds like a hypothetical spherical hydrogen bomb, it lacks the crucial layering that Sakharov proposed.

31

A group consisted of three to four squadrons of about fifteen aircraft each: forty to sixty operational aircraft in all, plus spares.