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Visualizing / Counting Radioactive Decay
Visualizing / Counting Radioactive Decay
Alpha Particles are being emitted from the Americium (Greatest of All the Elements). The sparks are a visual representation of the decay.
As the Americium decays, what element is produced?
What types of measurements could be made from the experiment?
Conceptual description of the structure of the spark counter.
Simulating Radioactive Decay
Simulating Radioactive Decay
Alpha Particles
Alpha Particles
2 Protons + 2 Neutrons
Alpha radiation occurs when an atom undergoes radioactive decay, giving off a particle (called an alpha particle) consisting of two protons and two neutrons (essentially the nucleus of a helium-4 atom), changing the originating atom to one of an element with an atomic number 2 less and atomic weight 4 less than it started with. Due to their charge and mass, alpha particles interact strongly with matter, and only travel a few centimeters in air. Alpha particles are unable to penetrate the outer layer of dead skin cells, but are capable, if an alpha emitting substance is ingested in food or air, of causing serious cell damage. Alexander Litvinenko is a famous example. He was poisoned by polonium-210, an alpha emitter, in his tea.
Alpha radiation: The emission of an alpha particle from the nucleus of an atom
How do atoms change as they undergo Alpha Particle Decay?
Alpha decay Problem.pdfAlpha Decay Questions.pdfBeta Particles
Beta Particles
two types: electron (beta minus) or positron (beta plus)
Beta radiation takes the form of either an electron or a positron (a particle with the size and mass of an electron, but with a positive charge) being emitted from an atom.
If a nucleus undergoes 𝜷- decay a neutron decays into a proton, electron and antineutrino. The resulting daughter nuclei then has one additional proton (Z+1), but an identical atomic mass (A).
Due to the smaller mass, it is able to travel further in air, up to a few meters, and can be stopped by a thick piece of plastic, or even a stack of paper. It can penetrate skin a few centimeters, posing somewhat of an external health risk. However, the main threat is still primarily from internal emission from ingested material.
Beta radiation: The emission of a beta particle from the nucleus of an atom
Beta Decay Problem.pdfBeta Decay Questions.pdfIn beta-minus decay a neutron is decaying into a proton and at the same time producing an electron and an antineutrino.
In beta-plus decay a proton is decaying into a neutron and at the same time producing a positron and a neutrino.
Experimenting with Radioactivity
Experimenting with Radioactivity
Magnetic steering
Magnetic steering
Alpha and Beta decay can be steered using a magnetic field — the range of alpha is such that this is hard to see outside of a cloud chamber — Beta on the other hand lends itself to the task. Here’s an example set-up, an experimenter can vary the position of the detector, with and without the magnetic field present.
Attenuation Rates
Attenuation Rates
The penetration or range of radiation depends on its energy, the material it encounters, and the type of radiation. (a) Greater energy means greater range. (b) Radiation has a smaller range in materials with high electron density. (c) Alphas have the smallest range, betas have a greater range, and gammas penetrate the farthest. OpenStax - C. 31.1
Attenuation:
In physics, attenuation or, in some contexts, extinction is the gradual loss of flux intensity through a medium. For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates.
In many cases, attenuation is an exponential function of the path length through the medium. In chemical spectroscopy, this is known as the Beer–Lambert law. In engineering, attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc.) and is represented by the attenuation coefficient of the medium in question.[1]
Effect of Shielding
Effect of Shielding
Measure the effect of various materials on the shielding effect.
Attenuation Rates of Gamma Rays (γ) by Lead (Pb) sheets data:
Attenuation Rates of Gamma Rays (γ) by Lead (Pb) sheets data:
The attenuation of γ rays through lead is approximately exponential:
Taking the natural log of this equation:
Therefore, the gradient of the line (-u) is the attenuation coefficient of the lead (Pb).
Nuclear Reaction Practice
Nuclear Reaction Practice
Cloud Chamber Visualization
Cloud Chamber Visualization
What is the primary function of a cloud chamber in physics experiments?
To measure the temperature of gases
To observe the trajectory of radioactive particles
To calculate the speed of sound in different mediums
To study the behavior of light waves
Which type of radiation is most easily observed in a cloud chamber?
Alpha particles
Beta particles
Gamma rays
X-raysd
In a cloud chamber, the trails left by alpha particles are typically:
Straight and long
Zigzag and short
Straight and short
Curved and long
Why is alcohol vapor often used in a cloud chamber?**
To create a conductive medium
To enhance the visibility of particle tracks
To maintain a constant temperature
To generate a magnetic field
When a Helmholtz coil is used to create a uniform magnetic field around a cloud chamber, how does this affect the observation of charged particles, and what can be inferred about these particles?
The magnetic field has no effect on the particle trajectories; thus, no additional information can be inferred.
The charged particles move in straight lines, indicating their mass and charge.
The charged particles follow curved paths, and the curvature can be used to determine their charge-to-mass ratio.
The magnetic field causes the particles to accelerate, allowing for the measurement of their velocity.
Explain how a cloud chamber works and why it is an effective tool for observing radioactive decay.
Discuss the historical significance and modern relevance of cloud chambers in the field of particle physics. How have cloud chambers contributed to our understanding of atomic and subatomic particles, and what are their limitations compared to more modern particle detectors?
Based on the observations made in a cloud chamber, how can one determine the energy levels of different types of radiation? Consider the length, thickness, and shape of the trails in your explanation.
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