Useful Tables

Section 12.0 Useful Tables

NUCLEAR WEAPONS FREQUENTLY ASKED QUESTIONS Version 2.01: 20 February 1999 COPYRIGHT CAREY SUBLETTE This material may be excerpted, quoted, or distributed freely provided that attribution to the author (Carey Sublette) and document name (Nuclear Weapons Frequently Asked Questions) is clearly preserved. I would prefer that the user also include the URL of the source. Only authorized host sites may make this document publicly available on the Internet through the World Wide Web, anonymous FTP, or other means. Unauthorized host sites are expressly forbidden. If you wish to host this FAQ, in whole or in part, please contact me at: careysub@earthling.net or dovesub@primenet.com This restriction is placed to allow me to maintain version control. The current authorized host sites for this FAQ are the High Energy Weapons Archive hosted/mirrored at: http://www.envirolink.org/issues/nuketesting/hew/ http://www.fas.org/nuke/hew/ http://www.warewulf.com/nuke and MilNet hosted at: http://www.milnet.com/milnet/nukeweap
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12.0 Useful Tables

CONVERSION FACTORS Unit Equivalent To 1 Kt 10^12 calories 4.19x10^12 joules (4.19x10^19 ergs) 2.62x10^31 eV (2.62x10^25 MeV) fission of 0.241 moles of material (1.45x10^23 nuclei) fission of approx. 57 g of material 1.16x10^6 kilowatt-hrs 3.97x10^9 BTU 1 eV 1.602177 x 10^-12 erg 11606 degree K 1 Bar 10^5 pascals (nt/m^2) 10^6 dyne/cm^2 0.98687 atmospheres 0.068948 PSI 1 calorie 4.1868 J Convenient Energy Content Approximations Fission of U-233: 17.8 Kt/kg Fission of U-235: 17.6 Kt/kg Fission of Pu-239: 17.3 Kt/kg Fusion of pure deuterium: 82.2 Kt/kg Fusion of tritium and deuterium (50/50): 80.4 Kt/kg Fusion of lithium-6 deuteride: 64.0 Kt/kg Fusion of lithium-7 deuteride Total conversion of matter to energy: 21.47 Mt/kg Fission of 1.11 g U-235: 1 megawatt-day (thermal) IMPORTANT UNITS OF MEASUREMENT Quantity Measured Unit Symbol Formula Microscopic Cross Section Barn b 10^-24 cm^2 Radioactivity Becquerel Bq 1 decay/sec Curie Ci 3.7x10^10 decay/sec Absorbed Radiation Dose Gray Gy 1 J/Kg Rad None 100 erg/g (.01 J/Kg) Biological Equivalent Dose Sievert Sv Grays*Q Rem None Rads*RBE Absorbed Gamma/X-Ray Dose Roentgen R 94 erg/g Immediate Explosive Energy Kiloton Kt 10^12 calories Radiation Biological Effect None RBE Radiation Quality Factor None Q Pressure Bar None 10^5 pascals (nt/m^2) PHYSICAL CONSTANTS [All constants are exact to the precision given] Quantity Symbol Value Unit Speed of Light in Vacuum c 2.99792458 x 10^10 cm/sec Planck Constant h 6.62608 x 10^-27 erg-sec Avogadro Constant N_A 6.02214 x 10^23 atom/mole Molar Gas Constant R 8.3145 x 10^7 erg/(mole K) Boltzmann Constant k 1.3806 x 10^-16 erg/K Stefan-Boltzmann Constant sigma 5.670 x 10^-5 erg/cm^2 K^4 sec Perfect Gas Standard Volume V_0 2.2414 x 10^5 cm^3 Atomic Mass Constant m_0 1.66054 x 10^-24 g m_0 9.31494 x 10^8 eV

Fissionable/Fissile Isotope Properties

Under reconstruction

Isotope Half-Life
(years) Primary Decay Mode Spontaneous Fission Rate - SF
(F/sec/kg) Fission Cross Section - sigma
(barns, fission spectrum avg) SF Neutron Multiplicity - nu_SF
(n/fission) Fission Spectrum Neutron Multiplicity - nu_FS
(n/fission) Critical Mass - M_c
(kg) Decay Heat - Q
(W/kg) Specific Activity
(curies/kg)

Th-232 1.405 x 10¹⁰ Alpha 4.083 MeV <5 x 10^-5 0.0785 - 2.16 None 2.654 x 10^-6 1.097 x 10^-4

Pa-231 32,760 Alpha 5.149 MeV <5 0.834 - 2.457 >188 1.442 47.23

U-232 68.9 Alpha 5.414 MeV 2 x 10 ^-3 2.013 2 3.296 >5 717.6 22,360

U-233 159,200 Alpha 4.909 MeV - 1.946 - 2.649 16 0.2804 9.636

U-234 245,500 Alpha 4.859 MeV 3.9 1.223 1.8 2.578 >41 0.1792 6.222

U-235 7.038 x 10⁸ Alpha 4.679 MeV 5.6 x 10^-3 1.235 2.0 2.6055 48 5.994 x 10^-5 2.161 x 10^-3

U-236 2.342 x 10⁷ Alpha 4.572 MeV 2.30 0.594 1.8 2.526 >167 1.753 x 10^-3 6.467 x 10^-2

U-238 4.468 x 10⁹ Alpha 4.270 MeV 5.51 0.308 1.96 2.6010 None 8.508 x 10^-6 3.361 x 10^-4

Isotope Half-Life Primary Decay Mode Spontaneous Fission Rate(F/sec/kg) Fission Cross Section SF Neutron Multiplicity Fission Spectrum Neutron Multiplicity Critical Mass Decay Heat (W/kg) Specific Activity (curies/kg)

Isotope Half-Life Primary Decay Mode Spontaneous Fission Rate(F/sec/kg) Fission Cross Section SF Neutron Multiplicity Fission Spectrum Neutron Multiplicity Critical Mass Decay Heat (W/kg) Specific Activity (curies/kg)

Isotope Properties and Neutron Cross Sections

This is subsection lists most isotopes of interest for direct, indirect, or theoretical nuclear weapon applications. Basic isotopes characteristics, and summary tables of significant neutron reaction cross sections are included.
The neutronic data is derived from the authoritative ENDF-VI evaluated nuclear data base compiled and maintained by the National Nuclear Data Center (NNDC) at the Brookhaven National Laboratory (BNL). The data listings below were prepared with the assistance of the Japan Atomic Energy Research Insititue (JAERI).
Notes:

The Maxwellian average cross sections are for a peak neutron energy distribution at 0.0253 eV (a room temperature thermal distribution).
Molar volume is the minimum volume per mole for the densest phase at standard pressure and temperature (STP)
SF = spontaneous fission
Critical mass estimates for the fissile isotopes are given for bare spheres at the densest STP phase. Where available these estimates are from other sources and are based either on actual experimental measurement, or reasonably sophisticated numerical computations. All fissile isotopes also include for comparison critical mass estimates made by me, using an exact criticality solution with a one-group representation of neutronic properties. The one-group parameters are fission spectrum averages calculated from the ENDF-VI evaluated nuclear data base.
As can be seen where outside critical mass estimates are also available, this one-group calculation method consistently underestimates the true critical mass - primarily because it does not take into account the effects of inelastic scattering in softening the neutron spectrum. The one-group calculated critical mass estimates are thus lower bounds on the true value. Comparison between the one-group calculations and the actual values for the highly fissile isotopes for which good experimental data is available (U-233, U-235, Pu-239, and Pu-241) shows a consistent underestimate of 70-75% of the true value. For less fissile isotopes, where critical mass estimates have been offered by others (these are mostly calculated estimates also, but with more sophisticated models), the underestimates are more severe (at worst 22-29% of the 'true' value for Pu-242). This too is to be expected because the effects of inelastic scattering is relatively greater in less fissile materials. On the other hand, the estimates for extremely fissile transuranics like the californium isotopes should be quite good.

Hydrogen

Atomic number: 1
Molar volume: 13.1 cm^3/mole (solid, 13 K)
Density: 0.0763 (solid, 13 K, natural hydrogen)
Melting point: 13.96 K (natural hydrogen)
Boiling point: 20.39 K

1-H-1

Atomic Mass: 1.007825032 +- 0.000000000 (amu)
Excess Mass: 7288.969 +- 0.001 keV
Binding Energy: 0.000 +- 0.000 keV
Stable Isotope
Atomic Percent Abundance: 99.985%
>Magnetic Moment: 2.7928 nuclear magnetons
Spin: 1/2+

Lightest possible atom, and consequently the most efficient neutron moderator. Widely used in nuclear weapon structural materials (i.e. plastics). Due to moderating ability and light weight, used to harden weapons against outside neutron fluxes (especially in combination with Li-6).
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 20.81 20.78 692.0 -3 3.927 elastic 20.47 20.47 692.0 -3 3.926 capture 332.0 -3 294.2 -3 149.1 -3 29.83 -6 39.27 -6 ---------------------------------------------------------------------------

1-H-2 (Deuterium)

Atomic Mass: 2.014101778 +- 0.000000000 (amu)
Excess Mass: 13135.720 +- 0.001 keV
Binding Energy: 2224.573 +- 0.002 keV
Stable Isotope
Atomic Percent Abundance: 0.015%
Spin: 1+
Magnetic Moment: 0.8574 nuclear magnetons
Quadrupole Moment: 0.003 barns

Best nuclear reactor moderator due to high moderating efficiency and extremely low abosrption cross section. A principal fusion fuel in thermonuclear weapons, can also be used for fusion boosting, and in neutron generators. Melting point 20.4 K, boiling point 23.67 K.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 3.390 3.390 801.5 -3 2.537 elastic 3.389 3.390 624.3 -3 2.532 (n,2n) (E-thr = 3.339 MeV) 177.2 -3 5.276 -3 capture 550.0 -6 487.4 -6 286.3 -6 9.521 -6 7.076 -6 ---------------------------------------------------------------------------

1-H-3 (Tritium)

Atomic Mass: 3.016049268 +- 0.000000001 (amu)
Excess Mass: 14949.794 +- 0.001 keV
Binding Energy: 8481.821 +- 0.004 keV
Beta Decay Energy: B- 18.591 +- 0.001 keV
Half Life: 12.33 years
Specific Activity: 9613 curie/g
Radioisotopic Power: 1.059 W/g
Primary Mode of Decay: Beta to He-3

Decay Energy: B- 18.591 +- 0.001 keV

Magnetic Moment: 2.9789 nuclear magnetons
Spin: 1/2+

A principal thermonuclear fuel, best used in conjunction with deuterium (the D+T reaction is the easiest by far to ignite, as well as one of the most energetic). It is produced in place by tritium breeding reactions in thermonuclear weapons. It can also manufactured and loaded into weapons (with deuterium) for use in fusion boosting of fission weapons, as the neutron source in neutron bombs and neutron generators for commercial or weapons use. Tritium is a pure beta emitter. Due to weak radiation emissions, it is used in safe luminescent displays. This nuclide is useful for thickness gauge of thin plastics.
Helium

Atomic number: 2
Molar volume: 32.05 cm^3/mole (liquid, 4.125 K)
Density: 0.1249 (liquid, 4.125 K, natural helium)
Boiling point: 4.125 K

2-He-3

Atomic Mass: 3.016029310 +- 0.000000001 (amu)
Excess Mass: 14931.204 +- 0.001 keV
Binding Energy: 7718.058 +- 0.002 keV
Stable Isotope
Atomic Percent Abundance: 0.000137%
Magnetic Moment: -2.1276 nuclear magnetons
Spin: 1/2+

This isotope is produced by the decay of tritium and so accumulates in fusion boosting reservoirs as an undesirable contaminant due to its high neutron absorption. It can be recycled to produce tritium by neutron bombardment. It is a valuable fusion fuel produced (and consumed) in the course of deuterium-deuterium fusion. Very rare in nature.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 5.331 +3 4.743 +3 1.168 2.941 elastic 3.135 3.135 954.4 -3 2.121 nonelastic 5.328 +3 4.722 +3 2.381 +3 213.8 -3 819.6 -3 capture 54.01 -6 47.88 -6 246.9 -6 35.18 -6 39.24 -6 (n,p) 5.328 +3 4.722 +3 2.381 +3 139.7 -3 816.9 -3 (n,d) (E-thr = 4.362 MeV) 74.07 -3 2.647 -3 ---------------------------------------------------------------------------

2-He-4

Atomic Mass: 4.002603250 +- 0.000000001 (amu)
Excess Mass: 2424.911 +- 0.001 keV
Binding Energy: 28295.673 +- 0.005 keV
Beta Decay Energy: B- -22895.261 +- 212.132 keV
Stable Isotope
Atomic Percent Abundance: 99.999863%
Magnetic Moment: 0.8220 nuclear magnetons
Quadrupole Moment: -0.001 barns
Spin: 0+

Most common natural isotope of helium. Widely used in industry as an inert gas. Produced as an end product of fusion reactions. This isotope has a zero cross section for all neutron reactions except scattering for neutron energies below 20 MeV.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 759.3 -3 759.3 -3 1.052 3.685 elastic 759.3 -3 759.3 -3 1.052 3.685 ---------------------------------------------------------------------------

Lithium

Atomic number: 3
Molar volume: 13.0 cm^3/mole
Density: 0.534
Melting point: 180.54 C
Boiling point: 1342 C

3-Li-6

Atomic Mass: 6.015122281 +- 0.000000510 (amu)
Excess Mass: 14086.312 +- 0.475 keV
Binding Energy: 31994.564 +- 0.475 keV
Beta Decay Energy: B- -4288.153 +- 5.448 keV
Stable Isotope
Atomic Percent Abundance: 7.42%
Spin: 1+
Magnetic Moment: 0.8220 nuclear magnetons
Quadrupole Moment: -0.001 barns

Natural lithium isotope used as a thermonuclear weapon fusion fuel, in the form of lithium deuteride, due to its production of tritium through the (n,t) reaction. The very high cross section of this reaction for thermalized neutrons, combined with the light weight of the Li-6 atom, make it useful in the form of lithium hydride for hardening of nuclear weapons against external neutron fluxes.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 941.1 837.2 1.431 1.900 elastic 734.5 -3 735.2 -3 906.4 -3 1.422 nonelastic 940.4 836.5 427.5 525.0 -3 478.0 -3 inelastic (E-thr = 1.751 MeV) 412.0 -3 142.8 -3 (n,2n) (E-thr = 6.614 MeV) 78.05 -3 190.5 -6 capture 38.50 -3 34.11 -3 17.47 -3 82.11 -6 28.06 -6 (n,p) (E-thr = 3.185 MeV) 6.766 -3 4.264 -3 (n,t) 940.3 833.4 424.9 28.04 -3 330.7 -3 ---------------------------------------------------------------------------

3-Li-7

Atomic Mass: 7.016004049 +- 0.000000507 (amu)
Excess Mass: 14907.673 +- 0.473 keV
Binding Energy: 39244.526 +- 0.473 keV
Beta Decay Energy: B- -861.815 +- 0.018 keV
Stable Isotope
Atomic Percent Abundance: 92.58%
Spin: 3/2-
Magnetic Moment: 3.2564 nuclear magnetons
Quadrupole Moment: -0.040 barns

Predominant isotope of natural lithium. Due to the large cross section for the (n,t) reaction at high neutron energies this isotope can breed substantial quantities of tritium in a fusion-driven chain reaction and thus serve as a fusion fuel. Although less efficient that Li-6 for this purpose, and not used in modern thermonuclear weapons it served this function in some early high yield weapons.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 1.015 1.012 1.470 1.845 elastic 970.0 -3 971.7 -3 1.025 1.660 nonelastic 45.40 -3 40.38 -3 1.078 444.9 -3 184.8 -3 inelastic (E-thr = 0.546 MeV) 365.0 -3 184.7 -3 (n,2n) (E-thr = 8.300 MeV) 70.09 -3 38.53 -6 capture 45.40 -3 40.24 -3 20.43 -3 1.930 -6 6.903 -6 (n,d) (E-thr = 8.868 MeV) 9.763 -3 10.98 -6 total (n,t) (E-thr = 2.822 MeV) 302.9 -3 20.04 -3 ---------------------------------------------------------------------------

Beryllium

Atomic number: 4
Molar volume: 4.8775 cm^3/mole
Density: 1.8477
Melting point: 1287 C
Boiling point: 2470 C

4-Be-9

Atomic Mass: 9.012182135 +- 0.000000425 (amu)
Excess Mass: 11347.584 +- 0.396 keV
Binding Energy: 58164.907 +- 0.396 keV
Beta Decay Energy: B- -1068.116 +- 0.899 keV
Stable Isotope
Atomic Percent Abundance: 100%
Spin: 3/2-

Beryllium is both an excellent neutron reflector and moderator, and is in addition very light. It has one of the highest neutron scattering cross sections per unit volume, and has very low neutron absorption. Beryllium is commonly used as a neutron reflector to make compact light-weight fission weapons. Beryllium also undergoes (n,2n) neutron multiplication reactions, which are not important for fission-spectrum neutons, but may have a significant role in fusion boosted systems. Beryllium can slo generate neutrons through Be-9(gamma,n)Be-8 and Be-9(a,n)C-12 reactions. When combined with an isotope that is a strong alpha-emitter but a weak gamma-emitter (usually Po-210), Be has been used in modulated neutron initiators for fission weapons. Pu-239/Be sources have been used as convenient laboratory neutron sources; Ra-226/Be and Am-241/Be neutron sources are useful for moisture gauges.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 6.159 6.158 1.494 2.834 elastic 6.151 6.151 959.3 -3 2.673 nonelastic 7.600 -3 6.754 -3 1.164 534.5 -3 161.1 -3 inelastic (E-thr = 8.784 MeV) 22.90 -3 38.95 -6 (n,2n) (E-thr = 1.868 MeV) 269.1 -3 53.83 -3 (n,2na) (E-thr = 1.749 MeV) 17.49 -3 4.938 -3 (n,2n)to 1st (E-thr = 2.701 MeV) 168.6 -3 66.50 -3 (n,2n)to 2nd (E-thr = 7.561 MeV) 28.68 -3 133.4 -6 capture 7.600 -3 6.735 -3 3.419 -3 323.1 -9 1.156 -6 (n,p) (E-thr = 14.260 MeV) 20.25 -9 (n,d) (E-thr = 16.300 MeV) 32.68 -9 (n,t) (E-thr = 11.610 MeV) 18.36 -3 2.751 -6 (n,a) (E-thr = 0.670 MeV) 9.419 -3 35.65 -3 ---------------------------------------------------------------------------

Boron

Atomic number: 5
Molar volume: 4.39 cm^3/mole (alpha form, 25 C)
Density: 2.46 (alpha form)
Melting point: 2076 C
Boiling point: 3900 C (estimated)

5-B-10
Atomic Mass: 10.012937027 +- 0.000000397 (amu)
Excess Mass: 12050.761 +- 0.370 keV
Binding Energy: 64750.700 +- 0.370 keV
Beta Decay Energy: B- -3647.807 +- 0.091 keV
Stable Isotope
Atomic Percent Abundance: 19.9%
Spin: 3+
This natural isotope is the best absorber of fast neutrons, and an excellent absorber of slow neutrons. As a component of natural boron, it is commonly used as a neutron absorber (control rod or burnable poison) in nuclear reactors. The separated isotpe has been used to harden nuclear weapons against external neutron fluxes, and to reduce the neutron preheating of fusion stages by fission triggers in thermonuclear weapons. Use of B-10 has been proposed to create "clean" (low fallout and low neutron emission) thermonuclear weapons.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 3.840 +3 3.415 +3 1.467 2.638 elastic 2.144 2.144 942.5 -3 2.062 nonelastic 3.838 +3 3.413 +3 1.726 +3 524.2 -3 575.3 -3 inelastic (E-thr = 0.791 MeV) 268.5 -3 70.84 -3 (n,2n) (E-thr = 8.980 MeV) 26.83 -3 33.22 -6 capture 500.0 -3 443.1 -3 224.9 -3 21.26 -6 76.03 -6 (n,p) 3.000 -3 2.659 -3 94.96 -3 37.51 -3 15.25 -3 (n,d) (E-thr = 4.801 MeV) 47.63 -3 1.249 -3 (n,a) 3.837 +3 3.400 +3 1.719 +3 48.95 -3 435.5 -3 (n,t2a) 12.00 -3 10.63 -3 305.2 -3 94.66 -3 52.28 -3 ---------------------------------------------------------------------------

5-B-11
Atomic Mass: 11.009305466 +- 0.000000451 (amu)
Excess Mass: 8667.984 +- 0.420 keV
Binding Energy: 76204.800 +- 0.421 keV
Beta Decay Energy: B- -1982.547 +- 0.854 keV
Stable Isotope
Atomic Percent Abundance: 80.1%
Spin: 3/2-
B-11 is the majority component of natural boron, and thus appears in boron mixtures used for nuclear applications where B-10 has not been separated.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 5.050 5.050 1.415 2.425 elastic 5.045 5.045 934.9 -3 2.396 inelastic (E-thr = 2.320 MeV) 298.3 -3 28.81 -3 (n,2n) (E-thr = 12.510 MeV) 1.414 -3 496.7 -9 (n,na) (E-thr = 9.460 MeV) 101.0 -3 27.54 -6 (n,np) (E-thr = 12.260 MeV) 1.104 -3 211.0 -9 (n,n2a) (E-thr = 12.150 MeV) 17.96 -3 3.696 -6 (n,nd) (E-thr = 17.270 MeV) 1.335 -9 (n,nt) (E-thr = 12.250 MeV) 747.4 -6 169.8 -9 capture 5.075 -3 4.513 -3 2.542 -3 0.000 5.473 -6 (n,p) (E-thr = 11.710 MeV) 4.021 -3 579.7 -9 (n,d) (E-thr = 9.830 MeV) 9.200 -3 4.074 -6 (n,t) (E-thr = 10.430 MeV) 14.96 -3 3.443 -6 (n,a) (E-thr = 7.240 MeV) 31.38 -3 63.13 -6 ---------------------------------------------------------------------------

Cobalt

Atomic number: 27
Molar volume: 6.61 cm^3/mole (25 C)
Density: 8.92 (25 C)
Melting point: 1493 C
Boiling point: 2930 C

27-Co-59
Atomic Mass: 58.9332002 +- 0.0000015 amu
Excess Mass: -62223.609 +- 1.420 keV
Binding Energy: 517308.113 +- 1.422 keV
Beta Decay Energy: B- -1072.484 +- 0.561 keV
Stable Isotope
Atomic Percent Abundance: 100%
Spin: 7/2-
Although the concept of the enhanced fallout "cobalt bomb", in which radioactive Co-60 is produced by fusion neutrons, is well known this isotope is not known to have been seriously considered for weapons applications. The 5.26 year half-life of Co-60 is too long to be of real military interest, which favors more intense shorter term effects.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 43.19 38.98 2.653 3.678 elastic 6.018 6.018 1.265 3.015 inelastic (E-thr = 1.118 MeV) 542.3 -3 655.5 -3 (n,2n) (E-thr = 10.630 MeV) 690.0 -3 180.0 -6 (n,na) (E-thr = 7.069 MeV) 1.765 -3 558.8 -9 (n,np) (E-thr = 7.496 MeV) 61.93 -3 56.52 -6 capture 37.18 32.96 75.51 1.121 -3 5.704 -3 (n,p) (E-thr = 0.796 MeV) 53.00 -3 1.484 -3 (n,d) (E-thr = 5.233 MeV) 5.673 -3 2.480 -6 (n,a) 0.000 0.000 20.24 -3 32.20 -3 165.1 -6 ---------------------------------------------------------------------------

Tantalum

Atomic number: 73
Molar volume: 10.84 cm^3/mole
Density: 16.69
Melting point: 2996 C
Boiling point: 5429 C

73-Ta-181
Atomic Mass: 180.9479963 +- 0.0000031 amu
Excess Mass: -48441.085 +- 2.892 keV
Binding Energy: 1452238.715 +- 2.903 keV
Beta Decay Energy: B- -187.890 +- 4.549 keV
Stable Isotope
Atomic Percent Abundance: 99.988%
Spin: 7/2+
Comprising nearly all of natural tantalum, this isotope was studied for possible use in enhanced fallout radiation weapons by the U.S. in the 1950s. Compared with Co-60 the shorter half-life of Ta-182 (115 days vs 2.56 years) and the higher cross section for epithermal neutrons made Ta-181 a more desirable candidate for this use.
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 26.32 24.02 5.370 7.005 elastic 5.650 5.640 2.991 4.614 inelastic (E-thr = 0.006 MeV) 241.9 -3 2.295 (n,2n) (E-thr = 7.686 MeV) 2.133 5.149 -3 (n,3n) (E-thr = 14.300 MeV) 6.300 -6 (n,np) (E-thr = 5.968 MeV) 163.1 -6 55.01 -9 capture 20.67 18.38 660.0 205.5 -9 85.66 -3 (n,p) (E-thr = 0.242 MeV) 3.723 -3 2.305 -6 (n,a) 45.94 -6 47.65 -6 1.579 116.4 -6 3.588 -3 ---------------------------------------------------------------------------

Thorium

Atomic number: 90
Molar volume: 19.80 cm^3/mole (25 C)
Density: 11.72 (25 C)
Melting point: 1842 C (+- 30 C)
Boiling point: 4820 C

90-Th-232
Atomic Mass: 232.0380504 +- 0.0000022 amu
Excess Mass: 35443.677 +- 2.036 keV
Binding Energy: 1766691.409 +- 2.061 keV
Beta Decay Energy: B- -494.958 +- 7.826 keV
Atomic Percent Abundance: 100%
Half Life: 1.405E10 Y
Specific Activity: 1.097E-7 curie/g
Radioisotopic Power: 2.654E-9 W/g
Primary Mode of Decay: Alpha to Ra-228

Decay Energy: 4.083 MeV

Secondary Mode of Decay: SF Spontaneous fission

Branch ratio: <1.0E-9 %
SF rate (fissions/sec/g) = <4E-6
Neutron emission rate (N/sec/g) = <6E-6

Spin: 0+
Critical mass: None

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 21.11 20.23 5.740 7.634 elastic 13.71 13.70 2.683 4.579 inelastic (E-thr = 0.049 MeV) 726.0 -3 2.875 (n,2n) (E-thr = 6.465 MeV) 1.181 14.46 -3 (n,3n) (E-thr = 11.610 MeV) 800.0 -3 113.6 -6 fission 0.000 0.000 636.3 -3 350.0 -3 78.48 -3 capture 7.400 6.532 84.35 0.000 85.70 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 1.896
Incident neutron 1E+05 eV Nu_p = 1.910
Incident neutron 1E+06 eV Nu_p = 2.040
Incident neutron 4E+06 eV Nu_p = 2.472
Incident neutron 2E+07 eV Nu_p = 4.774
Incident neutron fission spectrum average Nu_p = 2.159

Protactinium

Atomic number: 91
Molar volume: 15.18 cm^3/mole (25 C)
Density: 15.22 (Pa-231, 25 C)
Melting point: 1568 - 1575 C
Boiling point: unknown

91-Pa-231

Atomic Mass: 231.0358789 +- 0.0000028 amu
Excess Mass: 33420.973 +- 2.586 keV
Binding Energy: 1759860.436 +- 2.605 keV
Beta Decay Energy: B- -382.155 +- 3.220 keV
Half Life: 32760 Y
Specific Activity: 0.04723 curie/g
Radioisotopic Power: 0.001442 W/g
Primary Mode of Decay: Alpha to Ac-227

Decay Energy: 5.149 MeV

Secondary Mode of Decay: 24NEC

Branch ratio: 13E-10 %

Tertiary Mode of Decay: Spontaneous fission

Branch ratio: <=3E-10 %
SF rate (fissions/sec/g) = <5E-3
Neutron emission rate (N/sec/g) = <1E-2

Spin: 3/2-
Critical mass: no published estimate, 188 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 210.7 189.2 5.746 7.515 elastic 9.961 9.815 2.556 4.165 inelastic (E-thr = 0.009 MeV) 252.0 -3 2.231 (n,2n) (E-thr = 6.844 MeV) 724.0 -3 5.849 -3 (n,3n) (E-thr = 12.660 MeV) 134.0 -3 21.01 -6 fission 19.66 -3 16.99 -3 4.605 2.080 833.8 -3 capture 200.7 179.3 595.5 0.000 273.7 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.274
Incident neutron 1E+05 eV Nu_p = 2.285
Incident neutron 1E+06 eV Nu_p = 2.381
Incident neutron 4E+06 eV Nu_p = 2.702
Incident neutron 2E+07 eV Nu_p = 4.420
Incident neutron fission spectrum average Nu_p = 2.457

Uranium

Atomic number: 92
Molar volume: 12.56 cm^3/mole
Density: 18.95 (alpha form, stable to 667.8 C)
Melting point: 1132.2 C (+/- 0.8 C)
Boiling point: 3818 degrees C
specific heat 6.65 cal/mole/C (25 C)
tensile strength 450 MPa

92-U-232

Atomic Mass: 232.037146280 +- 0.000002857 (amu)
Excess Mass: 34601.531 +- 2.662 keV
Binding Energy: 1765968.847 +- 2.680 keV
Beta Decay Energy: B- -2750.000 +- 100.000 keV
Half Life: 68.9 Y
Specific Activity: 22.36 curie/g
Radioisotopic Power: 0.7176 W/g
Primary Mode of Decay: Alpha to Th-228

Decay Energy: 5.414 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: = 2E-16 %
SF rate (fissions/sec/g) = 2E-6
Neutron emission rate (N/sec/g) = 4E-6

Spin: 0+
Critical mass: no published estimate, 5.04 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 162.3 141.5 5.774 7.639 elastic 10.80 10.74 3.230 5.083 inelastic (E-thr = 0.048 MeV) 19.42 -3 509.2 -3 (n,2n) (E-thr = 7.286 MeV) 150.0 -3 484.1 -6 (n,3n) (E-thr = 13.210 MeV) 5.000 -3 562.0 -9 fission 76.66 66.42 363.8 2.370 2.013 capture 74.88 64.38 172.9 0.000 28.47 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E+00 eV Nu_p = 3.126
Incident neutron 1E+05 eV Nu_p = 3.136
Incident neutron 1E+06 eV Nu_p = 3.233
Incident neutron 4E+06 eV Nu_p = 3.554
Incident neutron 1.5E+07 eV Nu_p = 4.732
Incident neutron fission spectrum average Nu_p = 3.296

92-U-233

Atomic Mass: 233.039628196 +- 0.000003010 (amu)
Excess Mass: 36913.421 +- 2.804 keV
Binding Energy: 1771728.280 +- 2.821 keV
Beta Decay Energy: B- -1028.513 +- 51.640 keV
Half Life: 159200 Y
Specific Activity: 0.009636 curie/g
Radioisotopic Power: 0.0002804 W/g
Primary Mode of Decay: Alpha to Th-229

Decay Energy: 4.909 MeV

Spin: 5/2+
Critical mass: 16 kg (LA-10860-MS "Critical Dimensions of Systems Containing 235-U, 239-Pu, and 233-U; 1986 Rev."; De Volpi, A. in "Proliferation, Plutonium, and Policy", 1979, pg. 86), 11.63 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 588.4 522.2 5.920 7.665 elastic 11.97 11.94 2.889 4.447 inelastic (E-thr = 0.041 MeV) 174.6 -3 1.198 (n,2n) (E-thr = 5.779 MeV) 406.9 -3 4.078 -3 (n,3n) (E-thr = 13.060 MeV) 2.049 -3 1.380 -6 fission 531.2 468.9 774.2 2.450 1.946 capture 45.25 41.34 138.4 13.71 -9 70.30 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 2.53E-05 eV Nu_p = 2.487
Incident neutron 1E+05 eV Nu_p = 2.487
Incident neutron 1E+06 eV Nu_p = 2.565
Incident neutron 2E+06 eV Nu_p = 2.680
Incident neutron 1.4E+07 eV Nu_p = 4.223
Incident neutron fission spectrum average Nu_p = 2.649

92-U-234

Atomic Mass: 234.040945606 +- 0.000002122 (amu)
Excess Mass: 38140.580 +- 1.976 keV
Binding Energy: 1778572.444 +- 2.002 keV
Beta Decay Energy: B- -1809.846 +- 8.321 keV
Atomic Percent Abundance: 0.0055%
Half Life: 245500 Y
Specific Activity: 0.006222 curie/g
Radioisotopic Power: 0.0001792 W/g
Primary Mode of Decay: Alpha to Th-230

Decay Energy: 4.859 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 1.7E-9 %
SF rate (fissions/sec/g) = 3.9E-3
Neutron emission rate (N/sec/g) = 7.2E-3

Spin: 0+
Critical mass: no published estimate, 40.6 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 119.2 106.8 5.721 7.696 elastic 19.42 19.25 2.733 4.692 inelastic (E-thr = 0.044 MeV) 320.2 -3 1.557 (n,2n) (E-thr = 6.873 MeV) 473.0 -3 4.811 -3 (n,3n) (E-thr = 12.650 MeV) 127.0 -3 14.54 -6 fission 6.218 -3 5.536 -3 6.718 2.067 1.223 capture 99.75 87.53 631.3 25.77 -6 217.7 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E+00 eV Nu_p = 2.339
Incident neutron 1E+05 eV Nu_p = 2.353
Incident neutron 1E+06 eV Nu_p = 2.474
Incident neutron 4E+06 eV Nu_p = 2.879
Incident neutron 1.5E+07 eV Nu_p = 4.369
Incident neutron fission spectrum average Nu_p = 2.578

92-U-235

Atomic Mass: 235.043923062 +- 0.000002115 (amu)
Excess Mass: 40914.062 +- 1.970 keV
Binding Energy: 1783870.285 +- 1.996 keV
Beta Decay Energy: B- -123.716 +- 0.869 keV
Atomic Percent Abundance: 0.720%
Spin: 7/2- 7
Half Life: 7.038E8 Y
Specific Activity: 2.161E-6 curie/g
Radioisotopic Power: 5.994E-8 W/g
Primary Mode of Decay: Alpha to Th-231

Decay Energy: 4.679 MeV

Primary Mode of Decay: Spontaneous fission

Branch ratio: 7.0E-9%
SF rate (fissions/sec/g) = 5.6E-6
Neutron emission rate (N/sec/g) = 1.1E-5

Meta state at 0.000 Mev
Half Life: ~25 M
Primary Mode of Decay: IT to U-235
Spin: 1/2+
Critical mass: 48 kg (LA-10860-MS "Critical Dimensions of Systems Containing 235-U, 239-Pu, and 233-U; 1986 Rev."; De Volpi, A. in "Proliferation, Plutonium, and Policy", 1979, pg. 86"), 33.4 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 698.2 608.4 5.865 7.705 elastic 15.04 14.95 2.871 4.566 inelastic (E-thr = 0.000 MeV) 350.3 -3 1.804 (n,2n) (E-thr = 5.321 MeV) 542.9 -3 11.56 -3 (n,3n) (E-thr = 12.190 MeV) 41.79 -3 7.074 -6 fission 584.4 506.8 278.1 2.056 1.235 (n,4n) (E-thr = 17.970 MeV) 8.408 -9 capture 98.81 86.67 133.0 160.7 -9 89.07 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 2.53E-05 eV Nu_p = 2.4200
Incident neutron 1E+05 eV Nu_p = 2.4158
Incident neutron 1E+06 eV Nu_p = 2.5150
Incident neutron 2E+06 eV Nu_p = 2.6303
Incident neutron 4E+06 eV Nu_p = 2.8749
Incident neutron 1.4E+07 eV Nu_p = 4.3857
Incident neutron fission spectrum average Nu_p = 2.6055

92-U-236

Atomic Mass: 236.045561897 +- 0.000002091 (amu)
Excess Mass: 42440.627 +- 1.948 keV
Binding Energy: 1790415.042 +- 1.974 keV
Beta Decay Energy: B- -929.469 +- 50.427 keV
Spin: 0+
Half Life: 2.342E7 Y
Specific Activity: 6.467E-5 curie/g
Radioisotopic Power: 1.753E-6 W/g
Primary Mode of Decay: Alpha to Th-232

Decay Energy: 4.572 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 9.6E-8 %
SF rate (fissions/sec/g) = 0.00230
Neutron emission rate (N/sec/g) = 0.0041

Critical mass: no published estimate, 167 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 13.69 13.09 5.748 7.735 elastic 8.336 8.330 2.757 4.769 inelastic (E-thr = 0.045 MeV) 326.0 -3 2.256 (n,2n) (E-thr = 6.578 MeV) 487.3 -3 7.645 -3 (n,3n) (E-thr = 11.900 MeV) 522.9 -3 66.34 -6 fission 61.29 -3 54.44 -3 7.764 1.659 594.0 -3 capture 5.295 4.703 345.6 366.6 -9 107.6 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-03 eV Nu_p = 2.294
Incident neutron 1E+05 eV Nu_p = 2.307
Incident neutron 1E+06 eV Nu_p = 2.425
Incident neutron 4E+06 eV Nu_p = 2.818
Incident neutron 1.5E+07 eV Nu_p = 4.267
Incident neutron fission spectrum average Nu_p = 2.526

92-Uranium-238

Atomic Mass: 238.050782583 +- 0.000002126 (amu)
Excess Mass: 47303.664 +- 1.980 keV
Binding Energy: 1801694.651 +- 2.006 keV
Beta Decay Energy: B- -147.065 +- 1.145 keV
Atomic Percent Abundance: 99.2745%
Half Life: 4.468E+9 Y
Specific Activity: 3.361E-7 curie/g
Radioisotopic Power: 8.508E^-9 W/g
Primary Mode of Decay: Alpha to Th-234

Decay Energy: 4.270 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 0.000044 %
Average neutron yield (Nu)
Nu_prompt = 1.97 +- 0.07
SF rate (fissions/sec/g) = 0.00551
Neutron emission rate (N/sec/g) = 0.0108

Spin: 0+
Critical mass: none

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 12.09 11.77 5.805 7.786 elastic 9.360 9.356 2.704 4.804 inelastic (E-thr = 0.045 MeV) 698.3 -3 2.595 (n,2n) (E-thr = 6.179 MeV) 910.0 -3 12.07 -3 (n,3n) (E-thr = 11.330 MeV) 350.0 -3 61.90 -6 fission 11.77 -6 10.45 -6 2.020 1.136 308.4 -3 capture 2.717 2.414 278.1 1.943 -3 66.40 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 2.53000E-02 eV Nu_p = 2.4481
Incident neutron 1E+05 eV Nu_p = 2.4552
Incident neutron 1E+06 eV Nu_p = 2.5194
Incident neutron 2.9E+06 eV Nu_p = 2.6548
Incident neutron 5.15E+06 eV Nu_p = 3.0840
Incident neutron 2E+07 eV Nu_p = 5.1819
Incident neutron fission spectrum average Nu_p = 2.6010

Neptunium

Atomic number: 93
Molar volume: 11.59 cm^3/mole (25 C)
Density: 20.45 (Np-237, 25 C)
Melting point: 637 C
Boiling point: 4000 C

93-Np-237

Atomic Mass: 237.0481673 +- 0.0000021 amu
Excess Mass: 44867.501 +- 1.961 keV
Binding Energy: 1795277.138 +- 1.986 keV
Beta Decay Energy: B- -220.318 +- 1.298 keV
Half Life: 2.144E6 Y
Specific Activity: 7.034E-4 curie/g
Radioisotopic Power: 2.068E^-5 W/g
Primary Mode of Decay: Alpha to Pa-233

Decay Energy: 4.959 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: <=2E-10 %
SF rate (fissions/sec/g) = < 5.E-5
Neutron emission rate (N/sec/g) = < 1.E-4

Spin: 5/2+
Critical mass: 75-105 kg (Lovins, A.B. Nature. 283, p. 818, 1980; density adjusted), 18.5 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 192.1 171.2 5.539 7.799 elastic 27.46 27.14 2.606 4.965 inelastic (E-thr = 0.033 MeV) 105.6E-3 1.321 (n,2n) (E-thr = 6.657 MeV) 492.5E-3 3.120E-3 (n,3n) (E-thr = 12.370 MeV) 87.93E-3 14.05E-6 fission 22.49E-3 19.58E-3 7.058 2.247 1.335 capture 164.6 144.0 661.2 228.6E-9 173.4E-3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.625
Incident neutron 1E+05 eV Nu_p = 2.640
Incident neutron 1E+06 eV Nu_p = 2.775
Incident neutron 4E+06 eV Nu_p = 3.224
Incident neutron 2E+07 eV Nu_p = 5.521
Incident neutron fission spectrum average Nu_p = 2.889

Plutonium

Atomic number: 94
Molar volume: 12.061 cm^3/mole
Density: 19.816 (20 C)
Melting point: 639.5
Boiling point: 3230 C

94-Pu-238

Atomic Mass: 238.0495534 +- 0.0000021 amu
Excess Mass: 46158.688 +- 1.982 keV
Binding Energy: 1801274.921 +- 2.008 keV
Beta Decay Energy: B- -2258.350 +- 50.688 keV
Half Life: 87.7 Y
Specific Activity: 17.12 curie/g
Radioisotopic Power: 567.8 W/g
Primary Mode of Decay: Alpha to U-234

Decay Energy: 5.593 MeV
Secondary Mode of Decay: Spontaneous fission

Branch ratio: 1.9E-7 %
Average neutron yield (Nu)
Nu_prompt = 2.28 +- 0.10
SF rate (fissions/sec/g) = 1204.
Neutron emission rate (N/sec/g) = 2745.

Spin: 0+
Critical mass: 9 kg (Lovins, A.B. Nature. 283, p. 818, 1980), 5.26 kg (one-group calculation)
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 586.7 501.1 6.876 8.829 elastic 28.54 27.85 3.584 6.014 inelastic (E-thr = 0.044 MeV) 1.155 -3 716.6 -3 (n,2n) (E-thr = 7.028 MeV) 514.7 -3 3.669 -3 (n,3n) (E-thr = 12.930 MeV) 54.45 -3 13.71 -6 fission 17.89 15.18 32.69 2.721 1.994 capture 540.3 458.0 153.6 5.861 -9 99.30 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.891
Incident neutron 1E+05 eV Nu_p = 2.906
Incident neutron 1E+06 eV Nu_p = 3.039
Incident neutron 4E+06 eV Nu_p = 3.483
Incident neutron 1.4E+07 eV Nu_p = 4.964
Incident neutron fission spectrum average Nu_p = 3.148

94-Pu-239

Atomic Mass: 239.0521565 +- 0.0000021 amu
Excess Mass: 48583.478 +- 1.971 keV
Binding Energy: 1806921.454 +- 1.998 keV
Beta Decay Energy: B- -802.912 +- 2.011 keV
Half Life: 24110 Y
Specific Activity: 0.06203 curie/g
Radioisotopic Power: 0.001929 W/g
Primary Mode of Decay: Alpha to U-235

Decay Energy: 5.245 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 3E-10 %
Average neutron yield (Nu)
Nu_prompt =
SF rate (fissions/sec/g) = 7.E-3
Neutron emission rate (N/sec/g) = 2.E-2

Spin: 1/2+
Critical mass: 10.5 kg (LA-10860-MS "Critical Dimensions of Systems Containing 235-U, 239-Pu, and 233-U; 1986 Rev."; Glasstone, S. and Redman, L.M. in WASH-1037 Rev. "An Introduction to Nuclear Weapons", 1972, pg. 12), 7.403 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 1.026 +3 980.2 5.990 7.712 elastic 7.968 7.787 2.984 4.394 inelastic (E-thr = 0.008 MeV) 366.3 -3 1.460 (n,2n) (E-thr = 5.680 MeV) 290.1 -3 4.045 -3 (n,3n) (E-thr = 12.710 MeV) 11.50 -3 2.762 -6 fission 747.4 698.3 302.5 2.338 1.800 (n,4n) (E-thr = 18.590 MeV) 176.2 -12 capture 270.3 274.2 181.5 7.930 -9 52.94 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 2.53E-02 eV Nu_p = 2.8725
Incident neutron 1E+05 eV Nu_p = 2.8976
Incident neutron 1E+06 eV Nu_p = 3.0107
Incident neutron 4E+06 eV Nu_p = 3.4456
Incident neutron 1.4E+07 eV Nu_p = 4.9397
Incident neutron fission spectrum average Nu_p = 3.1231

94-Pu-240

Atomic Mass: 240.0538075 +- 0.0000021 amu
Excess Mass: 50121.319 +- 1.947 keV
Binding Energy: 1813454.935 +- 1.974 keV
Beta Decay Energy: B- -1378.952 +- 13.790 keV
Half Life: 6564 Y
Specific Activity: 0.227 curie/g
Radioisotopic Power: 0.00707 W/g
Primary Mode of Decay: Alpha to U-236

Decay Energy: 5.256 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 5.7E-6 %
Average neutron yield (Nu)
Nu_prompt = 2.189 +- 0.026
SF rate (fissions/sec/g) = 478.
Neutron emission rate (N/sec/g) = 1047.

Spin: 0+
Critical mass: 40 kg (Lovins, A.B. Nature. 283, p. 818, 1980; De Volpi, A. in "Proliferation, Plutonium, and Policy", 1979, pg. 86), 15.2 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 291.1 265.2 5.890 7.723 elastic 1.642 1.527 2.716 4.319 inelastic (E-thr = 0.043 MeV) 432.6 -3 1.950 (n,2n) (E-thr = 6.561 MeV) 373.1 -3 3.547 -3 (n,3n) (E-thr = 12.230 MeV) 113.5 -3 14.86 -6 fission 58.77 -3 53.41 -3 8.938 2.254 1.357 (n,4n) (E-thr = 19.260 MeV) 6.280 -9 capture 289.4 263.6 8.103 +3 800.0 -6 93.28 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.794
Incident neutron 4E+06 eV Nu_p = 3.402
Incident neutron 1.4E+07 eV Nu_p = 4.922
Incident neutron fission spectrum average Nu_p = 3.061

94-Pu-241

Atomic Mass: 241.0568453 +- 0.0000021 amu
Excess Mass: 52951.039 +- 1.948 keV
Binding Energy: 1818696.538 +- 1.975 keV
Beta Decay Energy: B- 20.815 +- 0.199 keV
Spin: 5/2+
Half Life: 14.35 Y
Specific Activity: 103.3 curie/g
Radioisotopic Power: 0.1294 W/g
Primary Mode of Decay: Beta to Am-241

Decay Energy: 0.021 MeV

Secondary Mode of Decay: Alpha to U-237

Branch ratio: 0.0025 %
Decay Energy: 5.140 MeV

Tertiary Mode of Decay: Spontaneous fission

Branch ratio: <2.E-14 %
SF rate (fissions/sec/g) = <8.E-4

Spin: 5/2+
Critical mass: 12 kg (Lovins, A.B. Nature. 283, p. 818, 1980; De Volpi, A. in "Proliferation, Plutonium, and Policy", 1979, pg. 86"), 9.03 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 1.385 +3 1.275 +3 5.799 7.840 elastic 11.35 11.14 3.290 5.168 inelastic (E-thr = 0.042 MeV) 2.002 -3 884.0 -3 (n,2n) (E-thr = 5.262 MeV) 114.3 -3 21.37 -3 (n,3n) (E-thr = 11.820 MeV) 95.00 -3 18.00 -6 fission 1.012 +3 938.0 572.6 2.298 1.648 (n,4n) (E-thr = 17.500 MeV) 22.74 -9 capture 361.5 326.1 179.9 105.0 -9 118.2 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.930
Incident neutron 1E+05 eV Nu_p = 2.930
Incident neutron 1E+06 eV Nu_p = 3.013
Incident neutron 4E+06 eV Nu_p = 3.490
Incident neutron 2E+07 eV Nu_p = 5.963
Incident neutron fission spectrum average Nu_p = 3.142

94-Pu-242

Atomic Mass: 242.0587368 +- 0.0000021 amu
Excess Mass: 54713.012 +- 1.966 keV
Binding Energy: 1825005.887 +- 1.993 keV
Beta Decay Energy: B- -750.963 +- 0.718 keV
Half Life: 3.733E5 Y
Specific Activity: 0.003956 curie/g
Radioisotopic Power: 0.0001169 W/g
Primary Mode of Decay: Alpha to U-238

Decay Energy: 4.984 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 0.00055 %
Average neutron yield (Nu)
Nu_prompt = 2.28 +- 0.13
SF rate (fissions/sec/g) = 805.
Neutron emission rate (N/sec/g) = 1840

Spin: 0+
Critical mass: 95 kg, range 75-100 kg (Lovins, A.B. Nature. 283, p. 818, 1980; De Volpi, A. in "Proliferation, Plutonium, and Policy", 1979, pg. 86"); 22.1 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 27.11 25.12 5.954 7.934 elastic 8.318 8.294 2.922 4.810 inelastic (E-thr = 0.043 MeV) 279.0 -3 1.900 (n,2n) (E-thr = 6.336 MeV) 433.3 -3 6.667 -3 (n,3n) (E-thr = 11.600 MeV) 289.2 -3 43.45 -6 fission 2.557 -3 2.279 -3 5.577 2.027 1.127 (n,4n) (E-thr = 18.160 MeV) 133.1 -9 capture 18.79 16.82 1.130 +3 800.0 -6 87.87 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 2.790
Incident neutron 1E+05 eV Nu_p = 2.806
Incident neutron 1E+06 eV Nu_p = 2.948
Incident neutron 4E+06 eV Nu_p = 3.421
Incident neutron 2E+07 eV Nu_p = 5.950
Incident neutron fission spectrum average Nu_p = 3.070

Americium

Atomic number: 95
Molar volume: 17.63 cm^3/mole
Density: 13.67 (Am-241, 25 C)
Melting point: 1175 C
Boiling point: 2607 C

95-Am-241

Atomic Mass: 241.0568229 +- 0.0000021 amu
Excess Mass: 52930.224 +- 1.957 keV
Binding Energy: 1817935.000 +- 1.984 keV
Beta Decay Energy: B- -767.357 +- 1.173 keV
Half Life: 432.2 Y
Specific Activity: 3.431 curie/g
Radioisotopic Power: 0.1147 W/g
Primary Mode of Decay: Alpha to Np-237

Decay Energy: 5.638 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 4E-10 %
SF rate (fissions/sec/g) = 0.5
Neutron emission rate (N/sec/g) = 1.

Spin: 5/2-
Critical mass: 83.5 kg (Lovins, A.B. Nature. 283, p. 818, 1980; density adjusted), 23 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 614.6 545.4 5.741 7.784 elastic 11.14 10.73 2.722 4.833 inelastic (E-thr = 0.041 MeV) 49.94 -3 1.340 (n,2n) (E-thr = 6.610 MeV) 262.4 -3 620.4 -6 (n,3n) (E-thr = 12.650 MeV) 46.74 -3 10.02 -6 fission 3.018 2.711 13.86 2.660 1.378 capture 600.4 532.0 1.305 +3 229.9 -9 229.6 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 3.235
Incident neutron 2E+05 eV Nu_p = 3.262
Incident neutron 1E+06 eV Nu_p = 3.369
Incident neutron 4E+06 eV Nu_p = 3.769
Incident neutron 1.4E+07 eV Nu_p = 5.057
Incident neutron fission spectrum average Nu_p = 3.457

95-Am-243

Atomic Mass: 243.0613727 +- 0.0000023 amu
Excess Mass: 57168.280 +- 2.178 keV
Binding Energy: 1829839.589 +- 2.203 keV
Beta Decay Energy: B- -8.908 +- 1.434 keV
Half Life: 7370 Y
Specific Activity: 0.1996 curie/g
Radioisotopic Power: 0.006433 W/g
Primary Mode of Decay: Alpha to Np-239

Decay Energy: 5.438 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 3.7E-9 %
SF rate (fissions/sec/g) = 0.27
Neutron emission rate (N/sec/g) = 0.76

Spin: 5/2-
Critical mass: no published estimate, 38.1 kg (one-group calculation, assuming the same ratio between one-group and multi-group values as Am-241 a 'true' value of 140 kg can be estimated)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 86.10 78.00 5.759 7.854 elastic 7.480 7.428 2.728 4.824 inelastic (E-thr = 0.042 MeV) 308.5 -3 1.754 (n,2n) (E-thr = 6.391 MeV) 360.5 -3 3.728 -3 (n,3n) (E-thr = 11.950 MeV) 221.1 -3 33.16 -6 fission 116.1 -3 103.3 -3 7.585 2.140 1.080 (n,4n) (E-thr = 18.570 MeV) 2.068 -9 capture 78.50 70.46 1.823 +3 230.7 -9 189.4 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 3.265
Incident neutron 2E+05 eV Nu_p = 3.292
Incident neutron 1E+06 eV Nu_p = 3.403
Incident neutron 4E+06 eV Nu_p = 3.812
Incident neutron 1.4E+07 eV Nu_p = 5.129
Incident neutron fission spectrum average Nu_p = 3.496

Californium

Atomic number: 98
Molar volume: 16.5 cm^3/mole
Density: 15.1 (Cf-249, 25 C)
Melting point: 900 C (+- 30 C)
Boiling point:

98-Cf-249
Atomic Mass: 249.0748468 +- 0.0000030 amu
Excess Mass: 69719.351 +- 2.806 keV
Binding Energy: 1863369.394 +- 2.826 keV
Beta Decay Energy: B- -1451.000 +- 30.000 keV
Half Life: 351 Y
Specific Activity: 4.089 curie/g
Radioisotopic Power: 0.1526 W/g
Primary Mode of Decay: Alpha to Cm-245

Decay Energy: 6.295 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 5.2E-7 %
SF rate (fissions/sec/g) = 787
Neutron emission rate (N/sec/g) = 2800

Spin: 9/2-
Critical mass: no published estimate, 5.90 kg (one-group calculation)
--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 2.177 +3 1.869 +3 5.817 8.082 elastic 6.223 5.989 2.747 4.952 inelastic (E-thr = 0.063 MeV) 65.64 -6 1.249 (n,2n) (E-thr = 5.616 MeV) 662.0 -3 14.19 -3 (n,3n) (E-thr = 12.620 MeV) 118.0 -3 24.69 -6 fission 1.666 +3 1.430 +3 2.219 +3 2.290 1.741 (n,4n) (E-thr = 18.660 MeV) 3.046 -9 capture 504.5 433.6 694.9 328.2 -12 120.8 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 3.884
Incident neutron 1E+05 eV Nu_p = 3.902
Incident neutron 1E+06 eV Nu_p = 4.061
Incident neutron 4E+06 eV Nu_p = 4.701
Incident neutron 1.1E+07 eV Nu_p = 5.880
Incident neutron fission spectrum average Nu_p = 4.221

98-Cf-251

Atomic Mass: 251.0795801 +- 0.0000049 amu
Excess Mass: 74128.333 +- 4.545 keV
Binding Energy: 1875103.058 +- 4.558 keV
Beta Decay Energy: B- -375.892 +- 7.107 keV
Half Life: 898 Y
Specific Activity: 1.586 curie/g
Radioisotopic Power: 0.05805 W/g
Primary Mode of Decay: Alpha to Cm-247

Decay Energy: 6.176 MeV

Spin: 1/2+
Critical mass: no published estimate, 1.94 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 7.889 +3 6.712 +3 5.838 8.148 elastic 76.09 70.15 2.754 4.814 inelastic (E-thr = 0.025 MeV) 10.20 -3 862.9 -3 (n,2n) (E-thr = 5.132 MeV) 268.1 -3 12.34 -3 (n,3n) (E-thr = 11.780 MeV) 325.2 -3 44.33 -6 fission 4.935 +3 4.196 +3 2.774 +3 2.478 2.430 (n,4n) (E-thr = 17.400 MeV) 59.29 -9 capture 2.878 +3 2.446 +3 1.604 +3 11.11 -9 27.45 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 4.133
Incident neutron 1E+05 eV Nu_p = 4.157
Incident neutron 1E+06 eV Nu_p = 4.374
Incident neutron 4E+06 eV Nu_p = 5.097
Incident neutron 1.15E+07 eV Nu_p = 6.917
Incident neutron fission spectrum average Nu_p = 4.560

98-Cf-252

Atomic Mass: 252.0816196 +- 0.0000055 amu
Excess Mass: 76028.139 +- 5.095 keV
Binding Energy: 1881274.575 +- 5.106 keV
Beta Decay Energy: B- -1260.000 +- 50.000 keV
Half Life: 2.645 Y
Specific Activity: 536.2 curie/g
Radioisotopic Power: 38.8 W/g (about half fission, half alpha decay)
Primary Mode of Decay: Alpha to Cm-248

Branch ratio: 96.91%
Decay Energy: 6.217 MeV

Secondary Mode of Decay: Spontaneous fission

Branch ratio: 3.09%
Average neutron yield (Nu)
Nu_prompt = 3.7590 +- 0.0048
Nu_delayed = 0.0086 +- 0.0010
Nu_total = 3.7676 +- 0.004
SF rate (fissions/sec/g) = 6.13E11
Neutron emission rate (N/sec/g) = 2.31E12

Spin: 0+
Critical mass: no published estimate, 2.73 kg (one-group calculation)

--------------------------------------------------------------------------- REACTION 2200-m/s Maxw.Avg. Res.Integ 14-MeV Fiss.Avg. (barns) (barns) (barns) (barns) (barns) --------------------------------------------------------------------------- total 64.77 58.49 5.848 8.186 elastic 11.04 11.02 2.758 5.144 inelastic (E-thr = 0.046 MeV) 10.29 -3 731.5 -3 (n,2n) (E-thr = 6.195 MeV) 86.60 -3 4.930 -3 (n,3n) (E-thr = 11.330 MeV) 223.0 -3 35.17 -6 fission 33.03 29.20 110.7 2.770 2.251 (n,4n) (E-thr = 17.980 MeV) 11.66 -9 capture 20.71 18.27 47.34 185.6 -9 51.29 -3 ---------------------------------------------------------------------------

Average neutron induced Nu_p (prompt neutrons/fission)

Incident neutron 1E-05 eV Nu_p = 4.060
Incident neutron 1E+05 eV Nu_p = 4.087
Incident neutron 1E+06 eV Nu_p = 4.325
Incident neutron 4E+06 eV Nu_p = 5.119
Incident neutron 1.5E+07 eV Nu_p = 7.961
Incident neutron fission spectrum average Nu_p = 4.374

Isotope	Half-Life (years)	Primary Decay Mode	Spontaneous Fission Rate - SF (F/sec/kg)	Fission Cross Section - sigma (barns, fission spectrum avg)	SF Neutron Multiplicity - nu_SF (n/fission)	Fission Spectrum Neutron Multiplicity - nu_FS (n/fission)	Critical Mass - M_c (kg)	Decay Heat - Q (W/kg)	Specific Activity (curies/kg)
Th-232	1.405 x 10¹⁰	Alpha 4.083 MeV	<5 x 10^-5	0.0785	-	2.16	None	2.654 x 10^-6	1.097 x 10^-4
Pa-231	32,760	Alpha 5.149 MeV	<5	0.834	-	2.457	>188	1.442	47.23
U-232	68.9	Alpha 5.414 MeV	2 x 10 ^-3	2.013	2	3.296	>5	717.6	22,360
U-233	159,200	Alpha 4.909 MeV	-	1.946	-	2.649	16	0.2804	9.636
U-234	245,500	Alpha 4.859 MeV	3.9	1.223	1.8	2.578	>41	0.1792	6.222
U-235	7.038 x 10⁸	Alpha 4.679 MeV	5.6 x 10^-3	1.235	2.0	2.6055	48	5.994 x 10^-5	2.161 x 10^-3
U-236	2.342 x 10⁷	Alpha 4.572 MeV	2.30	0.594	1.8	2.526	>167	1.753 x 10^-3	6.467 x 10^-2
U-238	4.468 x 10⁹	Alpha 4.270 MeV	5.51	0.308	1.96	2.6010	None	8.508 x 10^-6	3.361 x 10^-4
Isotope	Half-Life	Primary Decay Mode	Spontaneous Fission Rate(F/sec/kg)	Fission Cross Section	SF Neutron Multiplicity	Fission Spectrum Neutron Multiplicity	Critical Mass	Decay Heat (W/kg)	Specific Activity (curies/kg)
Isotope	Half-Life	Primary Decay Mode	Spontaneous Fission Rate(F/sec/kg)	Fission Cross Section	SF Neutron Multiplicity	Fission Spectrum Neutron Multiplicity	Critical Mass	Decay Heat (W/kg)	Specific Activity (curies/kg)