Discovery of Isotopes Project
In 2007 we began a project to document the discovery of all isotopes. In contrast to the
discovery of a new element, the first observation of a new isotope is not as well
defined.
We decided on two main guidelines for the claim of discovery of an isotope:
(1) Clean identification, either by decay curves and relationships to other known
isotopes, particle or γ-ray spectra, or unique mass and Z identification.
(2) The discovery had to be reported in a refereed journal.
In most cases the discovery is easy to determine. However, there are many cases
which are controversial for many different reasons.
We would appreciate any help in resolving the controversial cases. If you have
any information that might be helpful or if you disagree with an assignment please
let us know by sending an email.
For each isotope we write a brief paragraph describing the discovery, including
the authors, institution, year and method of discovery. The paragraph includes
a quote from the original paper and discusses any possible controversies related to
the discovery
These paragraphs are being published in a series of papers in the journal Atomic
Data and Nuclear Data Tables. The first paper summarized the discovery of the cerium
isotopes and was published in 2009.
The current publication status is as follows:
Published: 1137 isotopes of 42 elements
Accepted: 1245 isotopes of 38 elements
Submitted: 686 isotopes of 38 elements
In addition, 35 isotopes have been discovered after the publication of these articles for a total of 3103 isotopes known today.
The figure below summarizes the current status of the project:

We created a short movie of the timeline of the discoveries showing the different production mechanisms
Other related publications to the projects are:
"From isotopes to the stars"
Michael Thoennessen and Brad Sherrill
Nature 473 (2011) 25
doi:10.1038/473025a
"Isotope ranking reveals leading labs"
Eugenie Samuel Reich
Nature News, October 4, 2011
doi:10.1038/news.2011.571
"Seven days: 7-13 October 2011"
Trend Watch: Isotope ranking reveals leading labs
Nature 478 (2011) 160
doi:10.1038/478160a
"The Discoverers of the Ruthenium Isotopes "
Profile on page 258
Platinum Metals Rev. 55 (2011) 251
doi:10.1595/147106711X592448
"Trends in isotope discovery"
M. Thoennessen
CERN Courier December 2011, p. 62 (2011)
"The role of women in the discovery of isotopes"
M. Thoennessen
Proc. 4th Int. Conf. of Women in Physics 2011, AIP Conf. Proc.
to be published
The following undergraduate students were involved in the project:
S. Amos (REU, 2009), A. Bury (HSHSP, 2008), J. Claes (MSU, 2010), A. Fritsch (REU, 2008), C. Fry (REU, 2011),
K. Garofali (MSU, 2010), J.Q. Ginepro (PAPHC, 2007-2008), J.L. Gross (MSU, 2009-2011), M. Heim (REU, 2008),
J. Kathawa (MSU, 2010-2011), E. May (PAPHC, 2010-2011), D. Meierfrankenfeld (MSU, 2009),
A. Nystrom (REU, 2010), A. Parker (REU, 2010), R. Robinson (MSU, 2010-2011), A. Schuh (REU, 2008),
A. Shore (REU, 2008), T. Szymanski (MSU, 2009)
The projects has been funded by the NSF under grants:
PHY06-06007 (NSCL), PHY07-54541 (REU), PHY10-62410(REU), the High School Honors Science Program
(HSHSP) program, and the Professorial Assistantship Program of the Honors College (PAPHC) at MSU.
The table below lists the discoveries by elements, first contributor, and reference to the publication:
| Z = 0 - 10 | M. Thoennessen | At. Data Nucl. Data Tables 98, 43 (2012) |
| Z = 11 - 19 | M. Thoennessen | arXiv:1109.6537v1 |
| Z = 20 Calcium | J. Gross | At. Data Nucl. Data Tables 97, 383 (2011) |
| Z = 21 Scandium | D. Meierfrankenfeld | At. Data Nucl. Data Tables 97, 134 (2011) |
| Z = 22 Titanium | D. Meierfrankenfeld | At. Data Nucl. Data Tables 97, 134 (2011) |
| Z = 23 Vanadium | A. Shore | At. Data Nucl. Data Tables 96, 351 (2010) |
| Z = 24 Chromium | R. Robinson |
At. Data Nucl. Data Tables 98, 356 (2012) |
| Z = 25 Manganese | K. Garofali | At. Data Nucl. Data Tables 98, 356 (2012) |
| Z = 26 Iron | A. Schuh | At. Data Nucl. Data Tables 96, 817 (2010) |
| Z = 27 Cobalt | T. Szymanski | At. Data Nucl. Data Tables 96, 848 (2010) |
| Z = 28 Nickel | R. Robinson | At. Data Nucl. Data Tables 98, 356 (2012) |
| Z = 29 Copper | K. Garofali | At. Data Nucl. Data Tables 98, 356 (2012) |
| Z = 30 Zinc | J. Gross |
At. Data Nucl. Data Tables 98, 75 (2012) |
| Z = 31 Gallium | J. Gross | arXiv:1109.6306v1 |
| Z = 32 Germanium | J. Gross | arXiv:1109.6306v1 |
| Z = 33 Arsenic | A. Shore | At. Data Nucl. Data Tables 96, 299 (2010) |
| Z = 34 Selenium | J. Claes | At. Data Nucl. Data Tables 98, 75 (2012) |
| Z = 35 Bromium | J. Kathawa | At. Data Nucl. Data Tables 98, 75 (2012) |
| Z = 36 Krypton | M. Heim | At. Data Nucl. Data Tables 96, 333 (2010) |
| Z = 37 Rubidium | A. Parker | arXiv:1102.2388v1 |
| Z = 38 Strontium | A. Parker | arXiv:1102.2388v1 |
| Z = 39 Yttrium | A. Nystrom |
At. Data Nucl. Data Tables 98, 95 (2012) |
| Z = 40 Zirconium | A. Nystrom | At. Data Nucl. Data Tables 98, 95 (2012) |
| Z = 41 Niobium | A. Nystrom | At. Data Nucl. Data Tables 98, 95 (2012) |
| Z = 42 Molybenum | A. Parker | arXiv:1102.2388v1 |
| Z = 43 Technetium | A. Nystrom | At. Data Nucl. Data Tables 98, 95 (2012) |
| Z = 44 Ruthenium | A. Nystrom | At. Data Nucl. Data Tables 98, 95 (2012) |
| Z = 45 Rhodium | A. Parker | arXiv:1102.2388v1 |
| Z = 46 Palladium | J. Kathawa |
arXiv:1201.4348v1 |
| Z = 47 Silver | A. Schuh | At. Data Nucl. Data Tables 96, 531 (2010) |
| Z = 48 Cadmium | S. Amos | At. Data Nucl. Data Tables 96, 855 (2010) |
| Z = 49 Indium | S. Amos | At. Data Nucl. Data Tables 97, 383 (2011) |
| Z = 50 Tin | S. Amos | At. Data Nucl. Data Tables 97, 383 (2011) |
| Z = 51 Antimony | J. Kathawa | arXiv:1201.4348v1 |
| Z = 52 Tellurium | J. Kathawa | arXiv:1201.4348v1 |
| Z = 53 Iodine | J. Kathawa | arXiv:1201.4348v1 |
| Z = 54 Xenon | C. Fry | arXiv:1201.4348v1 |
| Z = 55 Cesium | E. May | arXiv:1109.1784v1 |
| Z = 56 Barium | A. Shore | At. Data Nucl. Data Tables 96, 749 (2010) |
| Z = 57 Lanthanum | E. May | arXiv:1109.1784v1 |
| Z = 58 Cerium | J.Q. Ginepro | At. Data Nucl. Data Tables 95, 905 (2009) |
| Z = 59 Praseodymium | E. May | arXiv:1109.1784v1 |
| Z = 60 Neodymium | J. Gross | At. Data Nucl. Data Tables 98, 75 (2012) |
| Z = 61 Promthium | E. May | arXiv:1109.1784v1 |
| Z = 62 Samarium | E. May |
arXiv:1201.4159v1 |
| Z = 63 Europium | E. May | arXiv:1201.4159v1 |
| Z = 64 Gadolinium | E. May | arXiv:1201.4159v1 |
| Z = 65 Terbium | E. May | arXiv:1201.4159v1 |
| Z = 66 Dysprosium | C. Fry | Manuscript |
| Z = 67 Holmium | C. Fry | Manuscript |
| Z = 68 Erbium | C. Fry | Manuscript |
| Z = 69 Thulium | C. Fry | Manuscript |
| Z = 70 Ytterbium | C. Fry | Manuscript |
| Z = 71 Lutetium | J. Gross | arXiv:1109.6306v1 |
| Z = 72 Hafnium | J. Gross | arXiv:1109.6306v1 |
| Z = 73 Tantalum | R. Robinson | arXiv:1109.0526v1 |
| Z = 74 Tungsten | A. Fritsch | At. Data Nucl. Data Tables 96, 315 (2010) |
| Z = 75 Rhenium | R. Robinson | arXiv:1109.0526v1 |
| Z = 76 Osmium | R. Robinson | arXiv:1109.0526v1 |
| Z = 77 Iridium | R. Robinson | arXiv:1109.0526v1 |
| Z = 78 Platinum | J. Gross | At. Data Nucl. Data Tables 97, 383 (2011) |
| Z = 79 Gold | A. Schuh | At. Data Nucl. Data Tables 96, 307 (2010) |
| Z = 80 Mercury | D. Meierfrankenfeld | At. Data Nucl. Data Tables 97, 134 (2011) |
| Z = 81 - 84 | C. Fry |
arXiv:1201.4474v1 |
| Z = 85 - 88 | C. Fry | Manuscript |
| Z = 89 - 92 | C. Fry | Manuscript |
| Z = 93 - 98 | C. Fry | Manuscript |
| Z = 99 Einsteinium | A. Bury | At. Data Nucl. Data Tables 97, 134 (2011) |
| Z = 100 - 118 | M. Thoennessen | Manuscript |