Nuclear properties of Isotopes

[Sensei]

Synthetic Hydrogen-4,5,6,7 are decaying through neutron emission to Hydrogen-3 very quickly,

and then Tritium is decaying to Helium-3, but it's long time process with 12.32 years half-life (long in comparison to 1st stage).

So why are you adding up these energies together?

There can be years delay between decay of ⁴H-⁷H and then decay to He-3.

Edited February 25, 2014 by Sensei

[occam]

Synthetic Hydrogen-4,5,6,7 are decaying through neutron emission to Hydrogen-3 very quickly,

and then Tritium is decaying to Helium-3, but it's long time process with 12.32 years half-life (long in comparison to 1st stage).

So why are you adding up these energies together?

There can be years delay between decay of ⁴H-⁷H and then decay to He-3.

Yes the 12 year 3H to 3He is the longest of all the steps but not in the lifetime of a star.

However it could account for the comparitively much larger abundance of 4He.

 

I add them together to show the total energy produced.

 

The key point is that the fusion process generates the source isotpes as the starting point. the solar energy output is produced by the decay process

[Sensei]

The key point is that the fusion process generates the source isotpes as the starting point. the solar energy output is produced by the decay process

 

Fusion process is giving much more energy than fission.

See table of fusion processes f.e. here

http://en.wikipedia.org/wiki/D-T_fusion#Criteria_and_candidates_for_terrestrial_reactions

 

Fission is serious source of energy in Earth's core. But it's completely not comparable to amount of energy produced by stars.

 

For instance decay energy of Tritium to Helium-3 is just 18.6 keV, 5.7 keV in kinetic energy of emitted electron, and the rest in neutrino (lost permanently if neutrino will escape star).

But Tritium fusion with Deuterium gives 17.6 MeV decay energy.

That's nearly 1000 times more energy.

If taking into account just 5.7 keV and 17.6 MeV (neutrino treating as lost) then it's 3000 more energy.

 

[occam]

I was expecting to see the “orphan parent” isotopes as products, or by-products of the high energy fusion events. However I cannot find any reference as to how these isotopes are created.

The only thing I can think of is that the pressure wave has two stages: the high pressure producing the fusion events, and the low pressure producing the oprphan parents.

Edited March 2, 2014 by occam

[occam]

Some observations on abundance: The data for this is in spreadsheet Fe56-58.xls which can be downloaded from https://drive.google.com/file/d/0B3pdkE0Liyu2SFJlYVpWclFueVk/edit?usp=sharing

From this the nuclear density curves can be drawn for the decay chains leading to the stable Isotopes. As can be seen the diagram for 56Fe is considerably more complex than those for 57 and 58.

This complexity is mainly due to the multiple decay modes of some Isotopes. The data tables therefore also show the relative probabilities of the daughter Isotopes. It is clear from the data that the most probable decay mode also has the highest decay energy. This allows a reasonable estimate of the proportions even where a probability is not given in the source data.

From the raw data, 56Fe has seven source isotopes; 57Fe has six source isotopes; and 58Fe has just four. But this simple view can be misleading.

 

In 56 Fe the chain from 61AS has only a 0.023% probability in the decay from 60Ge to 56Ni. Similarly the decay from 57Ti is only 0.3% and from 57V only 0.4%.

 

In the 57 chains only 58Sc has a full yield to 57Fe. The decay of 59Sc gives only 30% leading to 57Fe; similarly 58Ga allows 35% from 57Zn; 60As 35% also from 57Zn; and 59Ga only 3% at 58Zn. The remaining chain 57Ca is shared with 56Fe which takes 30% of the initial decay and another 33% at 57Sc. The net yield to 57Fe is 66% of 70% or only 46.2%

 

For 58Fe the chain from 59Sc is 70% in favour, but at 59V less than 1% continues to become 58Fe. The chain from 59Ga (and 59Zn) effectively terminates at the extremely long lived 2 beta decay 58Ni. Leaving just the chain from 58Sc, and the OP2 58Co.

[Sensei]

It's ridiculous to give links on forum that need your permission to view them.

You should zip your files, and attach them to posts IMHO.

 

Your graph is also unreadable - what is in X axis, what is in Y axis? I have no idea..

Axes should be rescaled to the right unit (that doesn't have exponent, like f.e. GeV instead of eV when energies are too large), and have titles.

 

It would make sense to make graph showing different daughter and parent isotopes half-life.

f.e. half-life on Y axis, and Z atomic number on X axis.

Edited July 27, 2014 by Sensei

[occam]

Apologies I set the permissions incorrectly

I hope I have now changed it,could someone check please.

You will find larger versions of the graphs in the spreadsheet

[Sensei]

Apologies I set the permissions incorrectly

I hope I have now changed it,could someone check please.

 

Thanks.

 

About your observation: see Uranium.

 

Both U-235 and U-238 (especially) have very very large half-life, counted in billion years.

Daughter product of their decays have small half-life (days), and grand daughter product have even smaller half-life (minutes).

 

Isotope Uranium-238

Protons 92 Neutrons 146

Mass 238.051

Nucleus Energy 221696 [MeV]

Uranium-238 -> Thorium-234 + alpha + 4.26992 MeV

Proton emission prohibited (-7.626 MeV)

Neutron emission prohibited (-6.15392 MeV)

Beta decay- prohibited (-0.147362 MeV)

Beta decay+ prohibited (-4.47952 MeV)

Electron capture prohibited (-3.45752 MeV)

 

Thorium-234 half-life 24.10 days

 

Isotope Thorium-234

Protons 90 Neutrons 144

Mass 234.044

Nucleus Energy 217964 [MeV]

Thorium-234 -> Radium-230 + alpha + 3.67171 MeV

Proton emission prohibited (-8.17297 MeV)

Neutron emission prohibited (-6.19007 MeV)

Thorium-234 -> Protactinium-234 + e- + Ve + 0.272928 MeV

Beta decay+ prohibited (-5.51087 MeV)

Electron capture prohibited (-4.48887 MeV)

 

Protactinium-234 half-life 1.17 minutes.

 

Isotope Protactinium-234

Protons 91 Neutrons 143

Mass 234.043

Nucleus Energy 217963 [MeV]

Protactinium-234 -> Actinium-230 + alpha + 4.11231 MeV

Proton emission prohibited (-5.68104 MeV)

Neutron emission prohibited (-5.21991 MeV)

Protactinium-234 -> Uranium-234 + e- + Ve + 2.19451 MeV

Beta decay+ prohibited (-1.29493 MeV)

Electron capture prohibited (-0.272928 MeV)

 

Uranium-234 half-life 2.455×10⁵ years

 

Isotope Uranium-234

Protons 92 Neutrons 142

Mass 234.041

Nucleus Energy 217961 [MeV]

Uranium-234 -> Thorium-230 + alpha + 4.85778 MeV

Proton emission prohibited (-6.63247 MeV)

Neutron emission prohibited (-6.84425 MeV)

Beta decay- prohibited (-1.8098 MeV)

Beta decay+ prohibited (-3.2165 MeV)

Electron capture prohibited (-2.19451 MeV)

 

Thorium-230 half-life 7.538×10⁴ years

 

ps. Posts #24 & #25 links don't work as well..

Edited July 27, 2014 by Sensei

[occam]

Actually there are two possible decay paths from 238U

see http://periodictable.com/Isotopes/092.238/index.full.dm.html

The most probable (alpha decay) can ultimately lead to 206Pb or 208Pb.

the other most unlikely mode is a 2b- decay to 238Pu which yields several of the rare earths

 

235U has four definite possible paths see http://periodictable.com/Isotopes/092.235/index.full.dm.html

 

the most probable leading to 207Pb with a very low probability to 206Pb

 

238U is not a "source" isotope

for this see http://periodictable.com/Isotopes/092.238/index2.full.dm.html

[Sensei]

Actually there are two possible decay paths from 238U

see http://periodictable.com/Isotopes/092.238/index.full.dm.html

The most probable (alpha decay) can ultimately lead to 206Pb or 208Pb.

the other most unlikely mode is a 2b- decay to 238Pu which yields several of the rare earths

 

It's hard to bother explaining decay branch that is happening in just 2.19×10⁻¹⁰% of decays of U-238... It's 1 decay per 456 billions decays that I showed.

 

I just wanted to show counter example to your claim that half-life of daughter isotope is higher than parent isotope.

238U is not a "source" isotope

 

You're mixing what is source.

During explosion of supernova existing lighter atoms are bombarded by free neutrons.

That doesn't mean that there will be created only uuh and uup etc, that will start decaying..

Somebody watching that graph might have such impression, because they're on top of it.

Edited July 27, 2014 by Sensei

[occam]

 

I just wanted to show counter example to your claim that half-life of daughter isotope is higher than parent isotope.

 

You're mixing what is source.

During explosion of supernova existing lighter atoms are bombarded by free neutrons.

That doesn't mean that there will be created only uuh and uup etc, that will start decaying..

Somebody watching that graph might have such impression, because they're on top of it.

Not quite

 

238U is the longest lived of the 238 sequence, which commences 238Th for b- chain, and 242Fm (alpha) to 238Cf and then b+ to 238U

The further (shorter life) decays happen for all subsequent decays for all sequences above 208

 

The point of the "source" is there are no precursors, so these must be the primary products of all stellar processes including supernovas

[Sensei]

I made this SpreadSheet for you:

 

 

 

Decay of isotopes with 56 mass number.zip

[occam]

This is the same data as you will find in IsosortB, column AE lines 483 to 493 What point are you trying to make?

[occam]

I suppose it hasn't helped that all the access permissions were set incorrectly!

 

Could someone please check that all the spreadsheets are accessible and downloadable?

 

Thanks

[Sensei]

Thank you. I tried couple firsts and now they're loading fine.

[occam]

As you can now read IsosortB I presume you have noticed that Uranium is produced from Thorium

[Sensei]

You can create any heavier isotope by bombarding lighter isotope by free neutrons.

Actually that's a way to detect free neutrons.

For instance if you will emit free neutrons to heavy water D₂O

once free neutron is absorbed by Deuterium, it's changing to Tritium ₁H³

Tritium is unstable and decays to ₂He³

[occam]

No

look at IsosortB

there is no neutron bombardment!

 

the decay mode is beta minus, which adds an extra shell electron at each decay stage.

[Sensei]

No

look at IsosortB

there is no neutron bombardment!

 

Neutron bombardment was in supernova (in large quantity), billions years ago.

That's how isotopes heavier than Iron were created (regular star fusion ends up on Iron).

 

Stable isotopes remained that way until now.

Unstable isotopes decayed and concentrated at more stable isotopes (like Uranium).

 

Th-237 + n0 -> Th-238

Thorium-238 -> Protactinium-238 + e- + Ve + 1.86299 MeV

Protactinium-238 -> Uranium-238 + e- + Ve + 3.45752 MeV

 

We can take any isotope in the lab, and bombard it by free neutrons (from Beryllium-9 because it's isotope that has the lowest energy needed to split it to Be-8 and free neutron) and produce new isotope, whatever you like.

Majority of elements with Z>92 are synthesized in the labs. The all Plutonium used in nuclear weapons is made by human using U-238 and Deuterium.

List of synthetic elements, made by human:

http://en.wikipedia.org/wiki/Synthetic_element

Neutron capture article

http://en.wikipedia.org/wiki/Neutron_capture

Read also about s-process and r-process, to learn how your Thorium was created in the first place:

http://en.wikipedia.org/wiki/S-process

http://en.wikipedia.org/wiki/R-process

Edited August 1, 2014 by Sensei