Bohrium - Nucleosynthesis - Cold Fusion

Cold Fusion

Before the first successful synthesis of hassium in 1981 by the GSI team, the synthesis of bohrium was first attempted in 1976 by scientists at the Joint Institute for Nuclear Research at Dubna using this cold fusion reaction. They detected two spontaneous fission activities, one with a half-life of 1-2 ms and one with a half-life of 5 s. Based on the results of other cold fusion reactions, they concluded that they were due to 261Bh and 257Db respectively. However, later evidence gave a much lower SF branching for 261Bh reducing confidence in this assignment. The assignment of the dubnium activity was later changed to 258Db, presuming that the decay of bohrium was missed. The 2 ms SF activity was assigned to 258Rf resulting from the 33% EC branch. The GSI team studied the reaction in 1981 in their discovery experiments. Five atoms of 262Bh were detected using the method of correlation of genetic parent-daughter decays. In 1987, an internal report from Dubna indicated that the team had been able to detect the spontaneous fission of 261Bh directly. The GSI team further studied the reaction in 1989 and discovered the new isotope 261Bh during the measurement of the 1n and 2n excitation functions but were unable to detect an SF branching for 261Bh. They continued their study in 2003 using newly developed bismuth(III) fluoride (BiF3) targets, used to provide further data on the decay data for 262Bh and the daughter 258Db. The 1n excitation function was remeasured in 2005 by the team at the Lawrence Berkeley National Laboratory (LBNL) after some doubt about the accuracy of previous data. They observed 18 atoms of 262Bh and 3 atoms of 261Bh and confirmed the two isomers of 262Bh.

In 2007, the team at LBNL studied the analogous reaction with chromium-52 projectiles for the first time to search for the lightest bohrium isotope 260Bh:

209
83Bi + 52
24Cr → 260
107Bh + n

The team successfully detected 8 atoms of 260Bh decaying by alpha decay to 256Db, emitting alpha particles with energy 10.16 MeV. The alpha decay energy indicates the continued stabilizing effect of the N=152 closed shell.

The team at Dubna also studied the reaction between lead-208 targets and manganese-55 projectiles in 1976 as part of their newly established cold fusion approach to new elements:

208
82Pb + 55
25Mn → 262
107Bh + n

They observed the same spontaneous fission activities as those observed in the reaction between bismuth-209 and chromium-54 and again assigned them to 261Bh and 257Db. Later evidence indicated that these should be reassigned to 258Db and 258Rf (see above). In 1983, they repeated the experiment using a new technique: measurement of alpha decay from a decay product that had been separated out chemically. The team were able to detect the alpha decay from a decay product of 262Bh, providing some evidence for the formation of bohrium nuclei. This reaction was later studied in detail using modern techniques by the team at LBNL. In 2005 they measured 33 decays of 262Bh and 2 atoms of 261Bh, providing an excitation function for the reaction emitting one neutron and some spectroscopic data of both 262Bh isomers. The excitation function for the reaction emitting two neutrons was further studied in a 2006 repeat of the reaction. The team found that the reaction emitting one neutron had a higher cross section than the corresponding reaction with a 209Bi target, contrary to expectations. Further research is required to understand the reasons.

Read more about this topic:  Bohrium, Nucleosynthesis

Other articles related to "cold fusion, fusion":

Cold Fusion - Cultural References
... In Undead Science, sociologist Bart Simon gives some examples of cold fusion in popular culture, saying that some scientists use cold fusion as a synonym ... name by software Coldfusion and a brand of protein bars (Cold Fusion Foods) ... Albert Einstein makes up a "cold fusion" science to help his niece start a romantic relationship ...
Fringe Physics - Examples - Contemporary
... A nuclear fusion reaction called cold fusion occurring near room temperature and pressure was reported by chemists Martin Fleischmann and Stanley Pons in March 1989 ... on the problem or participated in international conferences on cold fusion ... Energy decided to take another look at cold fusion to determine whether their policies towards the subject should be altered because of new experimental evidence, and ...
Martin Fleischmann - Conference Proceedings
... Proceedings of the 9th International Conference on Cold Fusion ... "Background to cold fusion the genesis of a concept" ... Tenth International Conference on Cold Fusion ...
Free Energy Suppression - Examples - Eugene Mallove
... was a notable proponent and supporter of research into cold fusion ... He authored the book Fire from Ice, which details the 1989 report of table-top cold fusion from Stanley Pons and Martin Fleischmann at the University of Utah ... Other researchers in the field of cold fusion have claimed to be subjected to suppression via academic pressure as well as via lack of funding ...
List Of Water Fuel Inventions - Cold Fusion
... For more details on this topic, see Cold fusion ... The 1989 experiment by Fleischmann and Pons claimed to demonstrate "anomalous heat production" in an electrolysis cell ...

Famous quotes containing the words fusion and/or cold:

    The sadistic person is as dependent on the submissive person as the latter is on the former; neither can live without the other. The difference is only that the sadistic person commands, exploits, hurts, humiliates, and that the masochistic person is commanded, exploited, hurt, humiliated. This is a considerable difference in a realistic sense; in a deeper emotional sense, the difference is not so great as that which they both have in common: fusion without integrity.
    Erich Fromm (1900–1980)

    O land of manure and mist, of dirty, cold rain.
    Petrus Augustus De Genestet (1829–1861)