Isotopes of calcium

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Isotopes of calcium  (20Ca)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
40Ca96.9% stable
41Ca trace 9.94×104 y ε 41K
42Ca0.647%stable
43Ca0.135%stable
44Ca2.09%stable
45Ca synth 163 d β− 45Sc
46Ca0.004%stable
47Casynth4.5 dβ− 47Sc
48Ca 0.187%6.4×1019 y β−β− 48Ti
Standard atomic weight Ar°(Ca)

Calcium (20Ca) has 26 known isotopes, ranging from 35Ca to 60Ca. There are five stable isotopes (40Ca, 42Ca, 43Ca, 44Ca and 46Ca), plus one isotope (48Ca) with such a long half-life that it is for all practical purposes stable. The most abundant isotope, 40Ca, as well as the rare 46Ca, are theoretically unstable on energetic grounds, but their decay has not been observed. Calcium also has a cosmogenic isotope, 41Ca, with half-life 99,400 years. Unlike cosmogenic isotopes that are produced in the air, 41Ca is produced by neutron activation of 40Ca. Most of its production is in the upper metre of the soil column, where the cosmogenic neutron flux is still strong enough. 41Ca has received much attention in stellar studies because it decays to 41K, a critical indicator of solar system anomalies. The most stable artificial isotopes are 45Ca with half-life 163 days and 47Ca with half-life 4.5 days. All other calcium isotopes have half-lives of minutes or less. [4]

Contents

Stable 40Ca comprises about 97% of natural calcium and is mainly created by nucleosynthesis in large stars. Similarly to 40Ar, however, some atoms of 40Ca are radiogenic, created through the radioactive decay of 40K. While K–Ar dating has been used extensively in the geological sciences, the prevalence of 40Ca in nature initially impeded the proliferation of K-Ca dating in early studies, with only a handful of studies in the 20th century. Modern techniques using increasingly precise Thermal-Ionization (TIMS) and Collision-Cell Multi-Collector Inductively-coupled plasma mass spectrometry (CC-MC-ICP-MS) techniques, however, have been used for successful K–Ca age dating, [5] [6] as well as determining K losses from the lower continental crust [7] and for source-tracing calcium contributions from various geologic reservoirs [8] [9] similar to Rb-Sr.

Stable isotope variations of calcium (most typically 44Ca/40Ca or 44Ca/42Ca, denoted as 'δ44Ca' and 'δ44/42Ca' in delta notation) are also widely used across the natural sciences for a number of applications, ranging from early determination of osteoporosis [10] to quantifying volcanic eruption timescales. [11] Other applications include: quantifying carbon sequestration efficiency in CO2 injection sites [12] and understanding ocean acidification, [13] exploring both ubiquitous and rare magmatic processes, such as formation of granites [14] and carbonatites, [15] tracing modern and ancient trophic webs including in dinosaurs, [16] [17] [18] assessing weaning practices in ancient humans, [19] and a plethora of other emerging applications.

List of isotopes


Nuclide
 Z N Isotopic mass (Da) [20]
[n 1] 		Half-life [1]
[n 2] 		Decay
mode [1]
[n 3] 		Daughter
isotope
[n 4] 		Spin and
parity [1]
[n 5] [n 6] 		Natural abundance (mole fraction)
Normal proportion [1] Range of variation
35Ca201535.00557(22)#25.7(2) ms β+, p (95.8%)34Ar1/2+#
β+, 2p (4.2%)33Cl
β+ (rare)35K
36Ca201635.993074(43)100.9(13) msβ+, p (51.2%)35Ar0+
β+ (48.8%)36K
37Ca201736.98589785(68)181.0(9) msβ+, p (76.8%)36Ar3/2+
β+ (23.2%)37K
38Ca201837.97631922(21)443.70(25) msβ+38K0+
39Ca201938.97071081(64)860.3(8) msβ+39K3/2+
40Ca [n 7] 202039.962590850(22) Observationally stable [n 8] 0+0.9694(16)0.96933–0.96947
41Ca202140.96227791(15)9.94(15)×104 y EC 41K7/2−Trace [n 9]
42Ca202241.95861778(16)Stable0+0.00647(23)0.00646–0.00648
43Ca202342.95876638(24)Stable7/2−0.00135(10)0.00135–0.00135
44Ca202443.95548149(35)Stable0+0.0209(11)0.02082–0.02092
45Ca202544.95618627(39)162.61(9) dβ−45Sc7/2−
46Ca202645.9536877(24)Observationally stable [n 10] 0+4×10−54×10−5–4×10−5
47Ca202746.9545411(24)4.536(3) dβ−47Sc7/2−
48Ca [n 11] [n 12] 202847.952522654(18)5.6(10)×1019 yβ−β− [n 13] [n 14] 48Ti0+0.00187(21)0.00186–0.00188
49Ca202948.95566263(19)8.718(6) minβ−49Sc3/2−
50Ca203049.9574992(17)13.45(5) sβ−50Sc0+
51Ca203150.96099566(56)10.0(8) sβ−51Sc3/2−
β−, n?50Sc
52Ca203251.96321365(72)4.6(3) sβ− (>98%)52Sc0+
β−, n (<2%)51Sc
53Ca203352.968451(47)461(90) msβ− (60%)53Sc1/2−#
β−, n (40%)52Sc
54Ca203453.972989(52)90(6) msβ−54Sc0+
β−, n?53Sc
β−, 2n?52Sc
55Ca203554.97998(17)22(2) msβ−55Sc5/2−#
β−, n?54Sc
β−, 2n?53Sc
56Ca203655.98550(27)11(2) msβ−56Sc0+
β−, n?55Sc
β−, 2n?54Sc
57Ca203756.99296(43)#8# ms [>620 ns]β−?57Sc5/2−#
β−, n?56Sc
β−, 2n?55Sc
58Ca203857.99836(54)#4# ms [>620 ns]β−?58Sc0+
β−, n?57Sc
β−, 2n?56Sc
59Ca203959.00624(64)#5# ms [>400 ns]β−?59Sc5/2−#
β−, n?58Sc
β−, 2n?57Sc
60Ca204060.01181(75)#2# ms [>400 ns]β−?60Sc0+
β−, n?59Sc
β−, 2n?58Sc
This table header & footer:
  1. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  2. ↑ Bold half-life – nearly stable, half-life longer than age of universe.
  3. ↑ Modes of decay:
    EC: Electron capture
    n: Neutron emission
    p: Proton emission
  4. ↑ Bold symbol as daughter – Daughter product is stable.
  5. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  6. ↑ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  7. ↑ Heaviest observationally stable nuclide with equal numbers of protons and neutrons
  8. ↑ Believed to undergo double electron capture to 40Ar with a half-life no less than 9.9×1021 y
  9. ↑ Cosmogenic nuclide
  10. ↑ Believed to undergo β−β− decay to 46Ti
  11. ↑ Primordial radionuclide
  12. ↑ Believed to be capable of undergoing triple beta decay with very long partial half-life
  13. ↑ Lightest nuclide known to undergo double beta decay
  14. ↑ Theorized to also undergo β− decay to 48Sc with a partial half-life exceeding 1.1+0.8
    −0.6    ×1021 years [21]

Calcium-48

About 2 g of calcium-48 Calcium-48 carbonate.png
About 2 g of calcium-48

Calcium-48 is a doubly magic nucleus with 28 neutrons; unusually neutron-rich for a light primordial nucleus. It decays via double beta decay with an extremely long half-life of about 6.4×1019 years, though single beta decay is also theoretically possible. [22] This decay can analyzed with the sd nuclear shell model, and it is more energetic (4.27  MeV) than any other double beta decay. [23] It can also be used as a precursor for neutron-rich and superheavy nuclei. [24] [25]

Calcium-60

Calcium-60 is the heaviest known isotope as of 2020. [1] First observed in 2018 at Riken alongside 59Ca and seven isotopes of other elements, [26] its existence suggests that there are additional even-N isotopes of calcium up to at least 70Ca, while 59Ca is probably the last bound isotope with odd N. [27] Earlier predictions had estimated the neutron drip line to occur at 60Ca, with 59Ca unbound. [26]

In the neutron-rich region, N = 40 becomes a magic number, so 60Ca was considered early on to be a possibly doubly magic nucleus, as is observed for the 68Ni isotone. [28] [29] However, subsequent spectroscopic measurements of the nearby nuclides 56Ca, 58Ca, and 62Ti instead predict that it should lie on the island of inversion known to exist around 64Cr. [29] [30]

Related Research Articles

<span class="mw-page-title-main">Calcium</span> Chemical element with atomic number 20 (Ca)

Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.

<span class="mw-page-title-main">Island of stability</span> Predicted set of isotopes of relatively more stable superheavy elements

In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted "magic numbers" of protons and neutrons in the superheavy mass region.

<span class="mw-page-title-main">Magic number (physics)</span> Number of protons or neutrons that make a nucleus particularly stable

In nuclear physics, a magic number is a number of nucleons such that they are arranged into complete shells within the atomic nucleus. As a result, atomic nuclei with a "magic" number of protons or neutrons are much more stable than other nuclei. The seven most widely recognized magic numbers as of 2019 are 2, 8, 20, 28, 50, 82, and 126.

<span class="mw-page-title-main">Double beta decay</span> Type of radioactive decay

In nuclear physics, double beta decay is a type of radioactive decay in which two neutrons are simultaneously transformed into two protons, or vice versa, inside an atomic nucleus. As in single beta decay, this process allows the atom to move closer to the optimal ratio of protons and neutrons. As a result of this transformation, the nucleus emits two detectable beta particles, which are electrons or positrons.

Uranium (92U) is a naturally occurring radioactive element (radioelement) with no stable isotopes. It has two primordial isotopes, uranium-238 and uranium-235, that have long half-lives and are found in appreciable quantity in Earth's crust. The decay product uranium-234 is also found. Other isotopes such as uranium-233 have been produced in breeder reactors. In addition to isotopes found in nature or nuclear reactors, many isotopes with far shorter half-lives have been produced, ranging from 214U to 242U. The standard atomic weight of natural uranium is 238.02891(3).

Natural tantalum (73Ta) consists of two stable isotopes: 181Ta (99.988%) and 180m
Ta
 (0.012%).

The alkaline earth metal strontium (38Sr) has four stable, naturally occurring isotopes: 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%). Its standard atomic weight is 87.62(1).

Germanium (32Ge) has five naturally occurring isotopes, 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Of these, 76Ge is very slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years (130 billion times the age of the universe).

Potassium has 25 known isotopes from 34
K to 57
K as well as 31
K, as well as an unconfirmed report of 59
K. Three of those isotopes occur naturally: the two stable forms 39
K (93.3%) and 41
K (6.7%), and a very long-lived radioisotope 40
K (0.012%)

Argon (18Ar) has 26 known isotopes, from 29Ar to 54Ar, of which three are stable. On the Earth, 40Ar makes up 99.6% of natural argon. The longest-lived radioactive isotopes are 39Ar with a half-life of 268 years, 42Ar with a half-life of 32.9 years, and 37Ar with a half-life of 35.04 days. All other isotopes have half-lives of less than two hours, and most less than one minute.

Chlorine (17Cl) has 25 isotopes, ranging from 28Cl to 52Cl, and two isomers, 34mCl and 38mCl. There are two stable isotopes, 35Cl (75.8%) and 37Cl (24.2%), giving chlorine a standard atomic weight of 35.45. The longest-lived radioactive isotope is 36Cl, which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second. The shortest-lived are proton-unbound 29Cl and 30Cl, with half-lives less than 10 picoseconds and 30 nanoseconds, respectively; the half-life of 28Cl is unknown.

Aluminium or aluminum (13Al) has 23 known isotopes from 21Al to 43Al and 4 known isomers. Only 27Al (stable isotope) and 26Al (radioactive isotope, t1/2 = 7.2×105 y) occur naturally, however 27Al comprises nearly all natural aluminium. Other than 26Al, all radioisotopes have half-lives under 7 minutes, most under a second. The standard atomic weight is 26.9815385(7). 26Al is produced from argon in the atmosphere by spallation caused by cosmic-ray protons. Aluminium isotopes have found practical application in dating marine sediments, manganese nodules, glacial ice, quartz in rock exposures, and meteorites. The ratio of 26Al to 10Be has been used to study the role of sediment transport, deposition, and storage, as well as burial times, and erosion, on 105 to 106 year time scales. 26Al has also played a significant role in the study of meteorites.

Beryllium (4Be) has 11 known isotopes and 3 known isomers, but only one of these isotopes is stable and a primordial nuclide. As such, beryllium is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes have such short half-lives that none are primordial and their abundance is very low. Beryllium is unique as being the only monoisotopic element with both an even number of protons and an odd number of neutrons. There are 25 other monoisotopic elements but all have odd atomic numbers, and even numbers of neutrons.

Neptunium (93Np) is usually considered an artificial element, although trace quantities are found in nature, so a standard atomic weight cannot be given. Like all trace or artificial elements, it has no stable isotopes. The first isotope to be synthesized and identified was 239Np in 1940, produced by bombarding 238
U
 with neutrons to produce 239
U
, which then underwent beta decay to 239
Np
.

Copernicium (112Cn) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 277Cn in 1996. There are seven known radioisotopes ; the longest-lived isotope is 285Cn with a half-life of 30 seconds.

Flerovium (114Fl) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 289Fl in 1999. Flerovium has six known isotopes, along with the unconfirmed 290Fl, and possibly two nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but 290Fl may have a longer half-life of 19 seconds.

Livermorium (116Lv) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 293Lv in 2000. There are six known radioisotopes, with mass numbers 288–293, as well as a few suggestive indications of a possible heavier isotope 294Lv. The longest-lived known isotope is 293Lv with a half-life of 53 ms.

<span class="mw-page-title-main">Calcium-48</span> Isotope of calcium

Calcium-48 is a scarce isotope of calcium containing 20 protons and 28 neutrons. It makes up 0.187% of natural calcium by mole fraction. Although it is unusually neutron-rich for such a light nucleus, its beta decay is extremely hindered, and so the only radioactive decay pathway that it has been observed to undergo is the extremely rare process of double beta decay. Its half-life is about 6.4×1019 years, so for all practical purposes it can be treated as stable. One factor contributing to this unusual stability is that 20 and 28 are both magic numbers, making 48Ca a "doubly magic" nucleus.

<span class="mw-page-title-main">Primordial nuclide</span> Nuclides predating the Earths formation (found on Earth)

In geochemistry, geophysics and nuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed. Primordial nuclides were present in the interstellar medium from which the solar system was formed, and were formed in, or after, the Big Bang, by nucleosynthesis in stars and supernovae followed by mass ejection, by cosmic ray spallation, and potentially from other processes. They are the stable nuclides plus the long-lived fraction of radionuclides surviving in the primordial solar nebula through planet accretion until the present; 286 such nuclides are known.

References

  1. 1 2 3 4 5 6 Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ↑ "Standard Atomic Weights: Calcium". CIAAW. 1983.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. ↑ Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
  5. ↑ Marshall, B. D.; DePaolo, D. J. (1982-12-01). "Precise age determinations and petrogenetic studies using the KCa method". Geochimica et Cosmochimica Acta. 46 (12): 2537–2545. doi:10.1016/0016-7037(82)90376-3. ISSN   0016-7037.
  6. ↑ admin. "K-Ca dating and Ca isotope composition of the oldest Solar System lava, Erg Chech 002 | Geochemical Perspectives Letters" . Retrieved 2024-10-16.
  7. ↑ admin. "Radiogenic Ca isotopes confirm post-formation K depletion of lower crust | Geochemical Perspectives Letters" . Retrieved 2024-10-16.
  8. ↑ Antonelli, Michael A.; DePaolo, Donald J.; Christensen, John N.; Wotzlaw, Jörn-Frederik; Pester, Nicholas J.; Bachmann, Olivier (2021-09-16). "Radiogenic 40 Ca in Seawater: Implications for Modern and Ancient Ca Cycles". ACS Earth and Space Chemistry. 5 (9): 2481–2492. doi:10.1021/acsearthspacechem.1c00179. ISSN   2472-3452.
  9. ↑ Davenport, Jesse; Caro, Guillaume; France-Lanord, Christian (2022-12-01). "Decoupling of physical and chemical erosion in the Himalayas revealed by radiogenic Ca isotopes". Geochimica et Cosmochimica Acta. 338: 199–219. doi:10.1016/j.gca.2022.10.031. ISSN   0016-7037.
  10. ↑ Eisenhauer, A.; Müller, M.; Heuser, A.; Kolevica, A.; Glüer, C. -C.; Both, M.; Laue, C.; Hehn, U. v.; Kloth, S.; Shroff, R.; Schrezenmeir, J. (2019-06-01). "Calcium isotope ratios in blood and urine: A new biomarker for the diagnosis of osteoporosis". Bone Reports. 10: 100200. doi:10.1016/j.bonr.2019.100200. ISSN   2352-1872. PMC   6453776 . PMID   30997369.
  11. ↑ Antonelli, Michael A.; Mittal, Tushar; McCarthy, Anders; Tripoli, Barbara; Watkins, James M.; DePaolo, Donald J. (2019-10-08). "Ca isotopes record rapid crystal growth in volcanic and subvolcanic systems". Proceedings of the National Academy of Sciences. 116 (41): 20315–20321. doi: 10.1073/pnas.1908921116 . ISSN   0027-8424. PMC   6789932 . PMID   31548431.
  12. ↑ Pogge von Strandmann, Philip A. E.; Burton, Kevin W.; Snæbjörnsdóttir, Sandra O.; Sigfússon, Bergur; Aradóttir, Edda S.; Gunnarsson, Ingvi; Alfredsson, Helgi A.; Mesfin, Kiflom G.; Oelkers, Eric H.; Gislason, Sigurður R. (2019-04-30). "Rapid CO2 mineralisation into calcite at the CarbFix storage site quantified using calcium isotopes". Nature Communications. 10 (1): 1983. doi:10.1038/s41467-019-10003-8. ISSN   2041-1723. PMC   6491611 . PMID   31040283.
  13. ↑ Fantle, Matthew S.; Ridgwell, Andy (2020-08-05). "Towards an understanding of the Ca isotopic signal related to ocean acidification and alkalinity overshoots in the rock record". Chemical Geology. 547: 119672. doi:10.1016/j.chemgeo.2020.119672. ISSN   0009-2541.
  14. ↑ Antonelli, Michael A.; Yakymchuk, Chris; Schauble, Edwin A.; Foden, John; Janoušek, Vojtěch; Moyen, Jean-François; Hoffmann, Jan; Moynier, Frédéric; Bachmann, Olivier (2023-04-15). "Granite petrogenesis and the δ44Ca of continental crust". Earth and Planetary Science Letters. 608: 118080. doi:10.1016/j.epsl.2023.118080. hdl: 20.500.11850/603069 . ISSN   0012-821X.
  15. ↑ admin. "Calcium isotope fractionation during melt immiscibility and carbonatite petrogenesis | Geochemical Perspectives Letters" . Retrieved 2024-10-16.
  16. ↑ Skulan, Joseph; DePaolo, Donald J.; Owens, Thomas L. (1997-06-01). "Biological control of calcium isotopic abundances in the global calcium cycle". Geochimica et Cosmochimica Acta. 61 (12): 2505–2510. doi:10.1016/S0016-7037(97)00047-1. ISSN   0016-7037.
  17. ↑ admin. "Calcium stable isotopes place Devonian conodonts as first level consumers | Geochemical Perspectives Letters" . Retrieved 2024-10-16.
  18. ↑ Hassler, A.; Martin, J. E.; Amiot, R.; Tacail, T.; Godet, F. Arnaud; Allain, R.; Balter, V. (2018-04-11). "Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs". Proceedings of the Royal Society B: Biological Sciences. 285 (1876): 20180197. doi:10.1098/rspb.2018.0197. ISSN   0962-8452. PMC   5904318 . PMID   29643213.
  19. ↑ Tacail, Théo; Thivichon-Prince, Béatrice; Martin, Jeremy E.; Charles, Cyril; Viriot, Laurent; Balter, Vincent (2017-06-13). "Assessing human weaning practices with calcium isotopes in tooth enamel". Proceedings of the National Academy of Sciences. 114 (24): 6268–6273. doi: 10.1073/pnas.1704412114 . ISSN   0027-8424. PMC   5474782 . PMID   28559355.
  20. ↑ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  21. ↑ Aunola, M.; Suhonen, J.; Siiskonen, T. (1999). "Shell-model study of the highly forbidden beta decay 48Ca → 48Sc". EPL . 46 (5): 577. Bibcode:1999EL.....46..577A. doi:10.1209/epl/i1999-00301-2. S2CID   250836275.
  22. ↑ Arnold, R.; et al. (NEMO-3 Collaboration) (2016). "Measurement of the double-beta decay half-life and search for the neutrinoless double-beta decay of 48Ca with the NEMO-3 detector". Physical Review D . 93 (11): 112008. arXiv: 1604.01710 . Bibcode:2016PhRvD..93k2008A. doi:10.1103/PhysRevD.93.112008.
  23. ↑ Balysh, A.; et al. (1996). "Double Beta Decay of 48Ca". Physical Review Letters. 77 (26): 5186–5189. arXiv: nucl-ex/9608001 . Bibcode:1996PhRvL..77.5186B. doi:10.1103/PhysRevLett.77.5186. PMID   10062737.
  24. ↑ Notani, M.; et al. (2002). "New neutron-rich isotopes, 34Ne, 37Na and 43Si, produced by fragmentation of a 64A MeV 48Ca beam". Physics Letters B. 542 (1–2): 49–54. Bibcode:2002PhLB..542...49N. doi:10.1016/S0370-2693(02)02337-7.
  25. ↑ Oganessian, Yu. Ts.; et al. (October 2006). "Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm + 48Ca fusion reactions". Physical Review C. 74 (4): 044602. Bibcode:2006PhRvC..74d4602O. doi: 10.1103/PhysRevC.74.044602 .
  26. 1 2 Tarasov, O. B.; Ahn, D. S.; Bazin, D.; et al. (11 July 2018). "Discovery of 60Ca and Implications For the Stability of 70Ca". Physical Review Letters. 121 (2): 022501. doi: 10.1103/PhysRevLett.121.022501 . PMID   30085743.
  27. ↑ Neufcourt, Léo; Cao, Yuchen; Nazarewicz, Witold; et al. (14 February 2019). "Neutron Drip Line in the Ca Region from Bayesian Model Averaging". Physical Review Letters. 122 (6): 062502. arXiv: 1901.07632 . doi:10.1103/PhysRevLett.122.062502. PMID   30822058.
  28. ↑ Gade, A.; Janssens, R. V. F.; Weisshaar, D.; et al. (21 March 2014). "Nuclear Structure Towards N = 40 60Ca: In-Beam γ -Ray Spectroscopy of 58, 60Ti". Physical Review Letters. 112 (11): 112503. arXiv: 1402.5944 . doi:10.1103/PhysRevLett.112.112503. PMID   24702356.
  29. 1 2 Cortés, M.L.; Rodriguez, W.; Doornenbal, P.; et al. (January 2020). "Shell evolution of N = 40 isotones towards 60Ca: First spectroscopy of 62Ti". Physics Letters B. 800: 135071. arXiv: 1912.07887 . doi: 10.1016/j.physletb.2019.135071 .
  30. ↑ Chen, S.; Browne, F.; Doornenbal, P.; et al. (August 2023). "Level structures of 56, 58Ca cast doubt on a doubly magic 60Ca". Physics Letters B. 843: 138025. arXiv: 2307.07077 . doi: 10.1016/j.physletb.2023.138025 .

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