Detecting Radiation

Summary

In this episode of Carpet Labs, we explore the detection of radiation, focusing on three main types: alpha particles, beta particles, and gamma rays. We delve into various techniques used by scientists to detect and measure radioactive particles, including the use of photographic film in radiation badges, the Geiger counter for auditory and count-based detection, the scintillation counter that detects light emissions from radiation interactions, and the visually striking cloud chamber that shows particle paths through alcohol vapor condensation. This informative video provides insights into how these methods help monitor radiation exposure and ensure safety.

Takeaways

• 📚 The video discusses different types of radiation: alpha particles, beta particles, and gamma rays, each with different characteristics and penetrating powers.
• 🛡️ Alpha particles have a relative charge of +2, essentially a helium nucleus, and low penetrating power.
• 🔋 Beta particles are essentially electrons from the nucleus with a single negative charge and moderate penetrating power.
• ⚡ Gamma rays are electromagnetic waves with no charge or mass but very high penetrating power.
• 🧬 Different isotopes emit different types of radiation under various circumstances, such as neutron ratio or atomic size.
• 📸 The first technique mentioned is the use of photographic film in a radiation badge, which darkens upon exposure to radiation and indicates when safe limits are reached.
• 📊 The Geiger counter is a common device for detecting radiation, producing an auditory click and a count of ionizing interactions within a tube of argon gas.
• ✨ The scintillation counter works by detecting light released when radiation interacts with a scintillating material, converting it into an electrical signal.
• 🌫️ The cloud chamber is a visual method for detecting radiation, showing the path of particles through a vapor that condenses around the ionized points.
• 👨‍🔬 Scientists use these techniques to detect the presence and behavior of radioactive particles, important in environments with high radiation exposure.
• 🎥 The script provides a comprehensive overview of radiation detection methods, suitable for educational purposes and understanding radiation safety.

Q & A

What are the three main types of radiation discussed in the video?

The three main types of radiation discussed are alpha particles, beta particles, and gamma rays.

What is the relative charge of alpha particles and what are they essentially made of?

Alpha particles have a relative charge of plus two and are essentially helium nuclei.

What is the origin of beta particles and what is their relative mass?

Beta particles originate from the nucleus and have the same relative mass as an electron.

How do gamma rays differ from alpha and beta particles in terms of charge and mass?

Gamma rays are electromagnetic waves and therefore have no relative charge or mass, unlike alpha and beta particles.

What is a radiation badge and how is it used in an occupational environment?

A radiation badge is a device containing photographic film encased in plastic, worn by workers in environments with radiation exposure to monitor their exposure levels.

How does photographic film in a radiation badge indicate when the safe limit of radiation exposure has been reached?

The photographic film darkens upon exposure to radiation. When it reaches a certain level of darkening, it indicates that the safe limit has been reached.

What is a Geiger counter and how does it detect ionizing radiation?

A Geiger counter is a device that detects ionizing radiation by using a tube filled with argon gas. When radiation passes into the tube, it ionizes the argon, causing an electrical signal that is counted and audibly indicated by a click.

How does a scintillation counter differ from a Geiger counter in detecting radiation?

A scintillation counter detects radiation by observing the release of photons of light when radiation interacts with a scintillating material, rather than ionizing gas as in a Geiger counter.

What is a cloud chamber and how does it visually represent the path of radiation particles?

A cloud chamber is a device that contains a vapor of alcohol, cooled by dry ice. When radiation ionizes the vapor, it causes condensation, creating a visible track of the particle's path through the vapor.

Why is the cloud chamber considered visually interesting and how does it differ from other detection techniques?

The cloud chamber is visually interesting because it provides a direct visual record of the path of radiation particles as condensation trails. Unlike other techniques, it is not quantitative but offers a unique visual representation of radiation.

What are the limitations of using photographic film as a radiation detection method?

Photographic film is not specific to one type of radiation and does not provide a quantitative measurement. It can only indicate exposure to radiation energy and when the safe limit has been reached.

Outlines

00:00

🔬 Introduction to Radiation Detection Techniques

This paragraph introduces the topic of the video, which is the detection of radiation. It outlines the main types of radiation: alpha particles with a +2 charge and low penetrating power, beta particles which are electrons with a -1 charge and moderate penetrating power, and gamma rays which are electromagnetic waves with high penetrating power. The paragraph also mentions the different isotopes and circumstances under which radiation is emitted. The focus then shifts to the various techniques used to detect radiation, including photographic film, Geiger counters, scintillation counters, and cloud chambers, which are used by scientists to monitor and study radioactive particles.

05:02

📸 Exploring Radiation Detection Methods

The second paragraph delves into the specifics of radiation detection methods. It begins with the use of photographic film in radiation badges, which darken upon exposure to radiation, serving as a qualitative indicator of radiation levels. The Geiger counter is then discussed, which detects ionizing radiation by ionizing argon gas within a tube, producing an electrical signal that is amplified and counted, providing both an auditory and visual measure of radiation. The scintillation counter is similar but detects radiation through the release of light photons, which are then amplified into an electrical signal. Lastly, the cloud chamber is introduced as a visually striking method for detecting radiation, where ionizing particles cause alcohol vapor to condense, forming visible tracks that indicate the path of radiation. The paragraph concludes by summarizing the four techniques and their applications in detecting alpha, beta, and gamma radiation.

Keywords

💡Radiation

Radiation refers to the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization. In the video, the theme revolves around detecting different types of radiation, which is crucial in various scientific and occupational environments to ensure safety and understand radioactive decay.

💡Alpha Particles

Alpha particles are a type of ionizing radiation consisting of two protons and two neutrons emitted by the nucleus of certain radioactive elements. They have a relative charge of plus two and are essentially a helium nucleus. The video explains that alpha particles have low penetrating power but can be detected using various techniques, such as photographic film and a cloud chamber.

💡Beta Particles

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei during beta decay. They have a moderate penetrating power and carry a negative charge. The script mentions beta particles as one of the main types of radiation that scientists detect and measure using different techniques.

💡Gamma Rays

Gamma rays are a form of electromagnetic radiation that is produced by the decay of atomic nuclei. They have a very high penetrating power and no charge or mass. In the video, gamma rays are discussed as a significant type of radiation that can be detected using devices like the Geiger counter and scintillation counter.

💡Isotopes

Isotopes are variants of a particular chemical element which differ in neutron number, and hence in nucleon number, but not in proton number. The script discusses how different isotopes emit different types of radiation under various circumstances, such as changes in neutron ratio or atomic size.

💡Radiation Badge

A radiation badge is a device worn by individuals in environments with potential radiation exposure, such as nuclear reactors or hospitals, to monitor the amount of radiation they are exposed to. The script describes how the badge contains photographic film that darkens upon exposure to radiation, signaling when safe limits are reached.

💡Geiger Counter

A Geiger counter is a device used for detecting and measuring ionizing radiation. It operates by ionizing a gas within a tube, producing an audible click for each particle detected. The video script mentions the Geiger counter as a stereotypical tool for detecting radiation, providing both an auditory and visual count of radiation interactions.

💡Scintillation Counter

A scintillation counter is a device that detects ionizing radiation by converting it into a flash of light. The light is then detected and converted into an electrical signal. The script explains that this technology is similar to the Geiger counter but works by detecting light emitted from a scintillating material upon radiation interaction.

💡Cloud Chamber

A cloud chamber is a device used to visualize the path of ionizing particles. It works by having a supersaturated vapor of alcohol that condenses along the path of the particles, forming visible tracks. The video describes the cloud chamber as a visually interesting method to detect radiation, particularly showing the different interactions of alpha, beta, and gamma rays with the vapor.

💡Ionization

Ionization is the process by which an atom or molecule gains or loses electrons, resulting in the formation of ions. In the context of the video, ionization is a key process in the detection of radiation, as it occurs when radiation interacts with the gas in a Geiger counter or the vapor in a cloud chamber, leading to the detection of radiation.

💡Photomultiplier

A photomultiplier is a type of photodetector that amplifies the current produced by the conversion of light into electrical current. In the script, it is mentioned in relation to the scintillation counter, where it amplifies the small amount of light produced by the scintillation process into a measurable electrical signal.

Highlights

Introduction to the video discussing detection of radiation and different types of radiation encountered.

Explanation of alpha particles, their charge, and low penetrating power.

Description of beta particles, their origin from the nucleus, and moderate penetrating power.

Introduction to gamma rays as electromagnetic waves with high penetrating power.

Different isotopes emit different types of radiation under various circumstances.

Overview of techniques for detecting radiation: photographic film, Geiger counter, scintillation counter, and cloud chamber.

Use of radiation badges in occupational environments with normal radiation exposure.

Photographic film's role in the initial identification of radioactivity and its use in radiation badges.

Functioning of a Geiger counter and its use in detecting ionizing radiation.

Description of the Geiger counter's audible click as an indicator of radiation detection.

Introduction to the scintillation counter and its method of detecting radiation through light emission.

Explanation of how a photomultiplier tube amplifies the light signal in a scintillation counter.

Introduction to the cloud chamber and its visually striking method of tracking radiation.

Description of the cloud chamber's setup involving alcohol vapor and dry ice.

Visual representation of radiation paths in the cloud chamber and the differences between alpha, beta, and gamma rays.

Comparison of the cloud chamber's visual appeal to its quantitative counterparts.

Summary of the video's content on alpha, beta, gamma radiation, and the four detection techniques.

Transcripts

hi everyone and welcome to this episode

of carpet labs in today's video we're

going to be discussing how we can detect

radiation so we're going to review what

the different types of radiation that we

encounter are and we're going to then

have a look at some of the different

techniques so photographic film the

Geiger counter scintillation counter and

the cloud chamber as for ways that that

we as scientists can detect the presence

of and behavior of different radioactive

particles and and rates that are given

off okay so when we are thinking we're

thinking about three main types of

radiation in this situation there there

are more that we've talked about more

recently but these are the three main

ones so alpha particles which have a

relative charge of plus two which is

essentially a helium nucleus and that

have a low penetrating power and we

talked about a beta particle which is

essentially an electron that comes

originates from the nucleus so it has

the same relative mass of an electron

and a Nega single negative charge and

with a moderate penetrating power and

then we're talking about gamma rays

which are electromagnetic waves rather

than particles as in as alpha and beta

are so they have no relative charge or

relative mass and but they have a very

high penetrating power okay so each of

these types of radiation is given out by

different isotopes and different kind of

amounts and under different

circumstances okay so we looked in the

previous video about what circumstances

an isotope would which which type of

radiation would be given off under

particular circumstances whether it's to

do with approach on a neutron ratio or

the sheer atomic size okay but so the

for kind of techniques we're going to

discuss here are different qualitative

or quantitative ways to detect different

types of radiation the first one is one

that would be really commonly used by

someone who is working in an environment

where background radiation or you know

like a radiation is a exposure is a

normal part of their their occupational

environment okay so someone who works at

in a nuclear reactor or who works in

handling our radioactive materials and

transporting to and from hospital

or works with patients in you know

radiotherapy ward at a hospital okay so

that it they have what's called a

radiation badge something that they

would be attached or pins to their

clothing that basically goes where there

you go

okay so it's got some photographic film

encased in in plastic now you might

remember from when we first started

talking about radioactivity that

photographic film is with the way that

they first identified this this

radioactivity in the first place

now that it darkens and when it's

exposed to different types of radiation

now this is not very specific to one

type of radiation alone it's not you

know only picking up alpha or only

picking up gamma or whatever and they're

just identifying and the exposure to

that energy and so it gradually darkens

over time and that when set reaches a

certain level that it indicates that the

safe limit has been safe limit has been

reached okay so once a kind of dis

colours to a certain point or then it

kind of gives off a certain signal that

it says that note that's that's it you

need to stop now okay because then that

shows that because you can't smell or

feel or hear the radiation interacting

with your body and so you need it as a

way to indicate when it's you need to

stop and remove yourself from the area

and once it's done it's done okay and

I'm a technique that is really useful

which is kind of your stereotypical

thing that you might have seen in movies

or seen in TV shows where they're

looking at things to do with radiation

it's called a Geiger counter okay we

have one here at school um and you may

have have seen an experienced than

before um but so the idea is that we

have that looks you know this is kind of

one example of a guy who can't oh but

not not the only one we have a

radioactive sample that's giving off

ionizing radiation and so and so what

happens is that their own izing

radiation passes into a little a little

kind of detector you know this kind of

this little cylinder that you see down

in the photo here and then it's kind of

blown up in this you Meucci what it does

is that radiation passes in to this tube

which contains argon gas and that where

it interacts with a particle of argon

that it causes that to become ionized

okay and then that ionized gas particle

ion particle is then then we kind of got

this this interaction that's happening

inside there that causes an electrical

signal to be registered within you know

so thinking about where it interacts

with the electrodes what that does is

that then it's connected up to a device

that counts it and so it records you

know that that interaction that that

thing but it also gives the very

characteristic click it's an all you

know gives an auditory signal as well as

actually counting it in terms of how

many um how much you know how many

interactions there have been so you know

so it's that classic kind of sound in

the movie that click it you can quickly

kind of sound and so that ionization of

argon gas causes the electrical signal

which is then amplified and recorded

okay so the more clicks are here the

more radiation is being detected okay

and so the fact that you can hear the

sound is also a really good indication

but you can also look at the rate of

counts as a way to to measure

radioactivity okay now we have a similar

kind of technology but rather than

looking at the ionization of gas that

it's causing what's called a

scintillation or which is the release of

photons of light they said the radiation

traveling into the scintillation kind of

the detector that there's certain this

certain material which which

scintillates or gives off a little burst

of light when that interaction happens

that light is given off and then it's

detected on a photosensitive surface so

I said a surface that is sensitive to

light and then you know registers kind

of a signal and that signal becomes

multiplied or it kind of it you know

kind of gets redirected and multiplied

and then it registers that as an

electrical signal in this photo so this

is this photo multiplier to you where it

takes that little bit of information and

then it actually amplifies it out okay

so it's similar sort of idea to the

Geiger counter bits just working with a

slightly different mechanism okay and

then we come to the last of our four

that we're gonna focus on today called a

cloud chamber visually by far the most

really most interesting to see and if

you ever get the chance to see

in real life it's fantastic we don't

have the capability to do it here at

school at this stage because you need

access to dry ice which is not easy to

come by and but so what happens you have

this this kind of this chamber that's

sort of set up that contains a vapor of

alcohol and and so what happens is that

you have dry ice at the bottom that

cools them so you get this vapor of

alcohol that forms in here and then you

cool it until it's basically the maximum

kind of vapor that's going to exist

inside that and so you've got heaps of

cold alcohol vapor in here you got a

radioactive source or a way of radiation

and to traveling and what it does is

that ionizes the vapor that it interacts

with so it causes to become ionized and

then that causes them to attract

together or stick together and condense

and so um that you get this kind of

visible track of condensation that forms

through that vapor okay because it's

really cold that you can see it really

clearly it doesn't dissipate you know so

it's not like okay well it just passes

through and then it's gone that actually

kind of you get this visual record of

where that particle had traveled and

there's a really there's some really

interesting things that you might be

able to come by and like some some

videos on YouTube and things that show

the path of particular particles through

this kind of environment because alpha

and beta and then the gamma rays that

are given off interact with the vapor in

a slightly different way and so what

that you know that produces visually

some really interesting looking effects

okay so it's not quantitative as such

and like some of the other techniques

are but it's certainly much more visual

okay so we've identified or you know

reminded ourselves an alpha beta and

gamma radiation as particles and waves

and how they they behave and then the

four different techniques that we can

use to detect this radiation

photographic film in the form of a

radiation badge the Geiger counter

scintillation counter and the cloud

chamber alright thanks very much for

watching bye for now