# A Temperature of beta decay radioisotope (Sr-90)

#### Dimitris Catzis

Hi,
I want to develop a Monte Carlo simulation to determine the temperature of a beta radioisotope (Sr-90) of a given mass for my master thesis in Computational Physics. I am rookie to simulations. How much time will take to develop such a code.

Thnaks a lot

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#### mathman

What do mean by temperature? I doubt if it has anything to do with its decay.

#### Dimitris Catzis

Hi,
thanks for your response.

A given mass of Sr-90 will has a raised temperature due to the collisions of the electrons of the beta decay with the medium (Sr-90)

Staff Emeritus
How much time will take to develop such a code.
A very long time, since there is no general answer. It's specific to the configuration you have.

#### PAllen

Also, it depends on time (as well as configuration and environment, as @Vanadium 50 noted). If you start with a chunk of isotope at some temperature, it will increase to some peak, then slowly decrease, as more and more final decay result accumulates.

#### Dimitris Catzis

Also, it depends on time (as well as cinfiguration and environment, as @Vanadium 50 noted). If you start with a chunk of isotope at some temperature, it will increase to some peak, then slowly decrease, as more and more final decay result accumulates.
That's the point of my research, to determine the thermal power degradation with time. The environment is space. I want to predict the capability of Sr-90 for RTG applications

Staff Emeritus
This looks like it's going to be one of those threads where the OP only sloooowwwwly tells us what the question is.

#### Dimitris Catzis

This looks like it's going to be one of those threads where the OP only sloooowwwwly tells us what the question is.
Sorry about that! As i said i am rookie!

#### mfb

Mentor
Well, you can fix it.

What is the decay chain?
What do you know about the system? What is its purpose? How large is the sample? What do you know about its environment, especially in terms of thermal considerations?

#### Dimitris Catzis

Sr-90--->(~30 Years beta)--->Y-90---->(~2.8 Days beta)--->Zr-90(stable). the main component is a sturdy container of a radioactive material (the fuel).Thermocouples are placed in the walls of the container, with the outer end of each thermocouple connected to a heat sink . Radioactive decay of the fuel produces heat. It is the temperature difference between the fuel and the heat sink that allows the thermocouples to generate electricity. The mass of the radioactive material is a few kg. The environment is space.
As first task i want to calculate the energy deposition into a mass. Then i would figure out how i can determine the temperature,

#### mfb

Mentor
If the container is shielded well then all the energy of the electrons will be absorbed and heat the material. After a few weeks (=probably before launch already) there will be one Y decay per Sr decay so you can add simply the energies.

#### Dimitris Catzis

If the container is shielded well then all the energy of the electrons will be absorbed and heat the material. After a few weeks (=probably before launch already) there will be one Y decay per Sr decay so you can add simply the energies.

Yes, i thought that! My problem now is to determine with a Monte Carlo the energy of each decay for the electrons as all the neutrinos escape.and the spectra is not linear.

#### mfb

Mentor
You can calculate it, but I'm sure there are literature values about the average energy the electrons.

#### Dimitris Catzis

You can calculate it, but I'm sure there are literature values about the average energy the electrons.
I read somewhere that taking the average energy of the electrons to calculate the energy deposition is quite different results.

Staff Emeritus
The slow drip, drip, drip as the question slowly pours out...

Where?

#### Dimitris Catzis

The slow drip, drip, drip as the question slowly pours out...

Where?
Nuclear Batteries and Radioisotopes (Authors: Prelas, M., Boraas, M., De La Torre Aguilar, F., Seelig, J.-D., Tchakoua Tchouaso, M., Wisniewski, D.)
page 97

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