There is no explosion risk associated with superfluid Helium in the LHC cooling system

We evaluate speculation about the possibility of a dangerous release of energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic system due to the occurrence of a " Bose-Nova ". Bose-Novae are radial bursts of rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC) undergoes a collapse due the interatomic potential being deliberately made attractive using a magnetic field close to the Feshbach resonance. Liquid 4 He has a monatomic structure with s-wave electrons, zero nuclear spin, no hyperfine splitting, and as a consequence no Feshbach resonance which would allow one to change its normally repulsive interactions to be attractive. Because of this, a Bose-Nova style collapse of 4 He is impossible. Additional speculations concerning cold fusion during these events are easily dismissed using the usual arguments about the Coulomb barrier at low temperatures, and are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We conclude that that there is no physics whatsoever which suggests that Helium could undergo any kind of unforeseen catastrophic explosion. It has been suggested that there may be some danger associated with the liquid Helium cryogenic system of the LHC. The issue under discussion is whether or not some kind of explosive event related to the phenomenon known as a " Bose-nova " could occur within the liquid Helium, as superfluid liquid 4 He is a type of Bose condensate. There have also been suggestions that Bose-nova events are actually signals of a type of cold nuclear fusion [1, 2]. Liquid Helium is a substance with a long history of usage, and absolutely no history of spontaneous explosions. The only hazard listed by the U.S. Occupational Safety and Health Administration is that it is a " simple asphyxiant ". It was first liquefied in 1908, and is routinely used all over the world by physics departments in condensed matter experiments. Furthermore, it has been used in 1 high energy physics as a target in bubble chambers so the exercise of a beam impinging on liquid Helium is one that has been repeated millions of times without incident. One recent example of the use of liquid Helium as a target is at the Japanese RIKEN Laboratory [3]. A Bose-Einstein condensate (BEC) can form when the de Broglie wavelengths of individual particles become larger than their typical separation, and the atoms condense into an entity exhibiting collective dynamics [4]. Since the …