# Geiger counter

#### Matthias32

A magnet is directly between a Geiger counter and a radioactive material. If no radioactivity is registered, what kind of particles are being emitted by the radioactive substance?

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#### Jelfish

What are the different types of radiation? Then think about how a magnet could affect (or not affect) each one.

#### Nerro

$$\alpha$$ particles are helium cores, so $$^4_2He^{2+}$$ particles. Their charge makes them succeptible to magnetic fields.

$$\beta$$ particles are electrons so $$^{0}_{-1}e^-$$ which are charged and as such succeptible to magnetic fields, however they move very fast and are in that sense relatively immune to such interactions.

$$\gamma$$ particles are just photons without charge which means they should not be affected by the field.

Conclusion, most likely you had an $$\alpha$$ emitter.

#### Aprilshowers

So what does the magnet do to the Alpha particles?

So what does the magnet do to the Alpha particles that keeps
them from being detected by the Geiger counter?

#### Nerro

it attracts them and it might deflect them from the geiger counter.

My point was that you first have to look at the differences between the types of radiation and the influence the magnet might have on them.

#### Astronuc

Staff Emeritus
Nerro said:
$$\alpha$$ particles are helium cores, so $$^4_2He^{2+}$$ particles. Their charge makes them succeptible to magnetic fields.

$$\beta$$ particles are electrons so $$^{0}_{-1}e^-$$ which are charged and as such succeptible to magnetic fields, however they move very fast and are in that sense relatively immune to such interactions.

$$\gamma$$ particles are just photons without charge which means they should not be affected by the field.
Neutral particles are not affected by magnetic fields.

Remember, Fmag = q (v x B)

#### Nerro

which particle would you call neutral here?

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