science

Thulium-170

Thulium-170 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Thulium-170 rather than just read about it. In short: Thulium-170 (170Tm or Tm-170) is a radioactive isotope of thulium proposed for use in radiotherapy and in radioisotope thermoelectric generators. Properties Thulium-170 has a half-life of 128.6 days, decaying by β− to 170Yb about 99.87% of the time, and by electron capture to 170Er about 0.13% of the time.

Key takeaways

Thulium-170 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Thulium-170 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Thulium-170 from memory before moving on to harder problems.

Reference excerpt

Thulium-170 (170Tm or Tm-170) is a radioactive isotope of thulium proposed for use in radiotherapy and in radioisotope thermoelectric generators.

Properties Thulium-170 has a half-life of 128.6 days, decaying by β− to 170Yb about 99.87% of the time, and by electron capture to 170Er about 0.13% of the time. About 18.1% of β− decays populate an excited state of 170Yb at 84.25474(8) keV and this produces the main gamma ray emission from 170Tm; lower-energy photons are also produced through X-ray fluorescence at 7.42, 51.354, 52.389, 59.159, 59.383, and 60.962 keV. The ground state of thulium-170 has a spin of 1−. The charge radius is 5.2303(36) fm, the magnetic moment is 0.2458(17) μN, and the electric quadrupole moment is 0.72(5) e⋅b.

Proposed applications As a rare-earth element, thulium-170 can be used as the pure metal or thulium hydride, but the most common form is as thulium oxide (Tm2O3) due to the refractory properties of that compound. The isotope can be prepared in a reactor by neutron irradiation of natural thulium, which has a high neutron capture cross section of 103 barns.

Medicine In 1953, the Atomic Energy Research Establishment introduced thulium-170 as a candidate for radiography in medical and steelmaking contexts, but this was deemed unsuitable due to the predominant high-energy bremsstrahlung radiation, poor results on thin specimens, and long exposure times. However, 170Tm has been proposed for radiotherapy because the isotope is simple to prepare into a biocompatible form, and the low-energy radiation can selectively irradiate diseased tissue without causing collateral damage.

Radiothermal generator 170Tm2O3 has been proposed as a radiothermal source due to it being safer, cheaper, and more environmentally friendly than commonly used materials that contain isotopes such as plutonium-238. The heat output from a 170Tm source is initially much greater than from a 238Pu source relative to mass, but it declines rapidly due to its shorter half-life.

References

Worked examples

Example 1 — a first encounter with Thulium-170

Start with the simplest possible case. Write down what Thulium-170 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Thulium-170 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Thulium-170 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Thulium-170

In research: Thulium-170 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Thulium-170 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Thulium-170 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Isotopes of thulium, so understanding it makes those chapters shorter.
In everyday life: Look for Thulium-170 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Thulium-170 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Thulium-170 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Thulium-170 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Thulium-170 in simple terms?

Thulium-170 (170Tm or Tm-170) is a radioactive isotope of thulium proposed for use in radiotherapy and in radioisotope thermoelectric generators. Properties Thulium-170 has a half-life of 128.6 days, decaying by β− to 170Yb about 99.87% of the time, and by electron capture to 170Er about 0.13% of t…

Why does Thulium-170 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Thulium-170?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Thulium-170.