Acceleration of Particles

“I need to talk of what I don't know yet, So that I may perceive whatever holds The world together in its inmost folds, See all its seeds, its working power…”
Goethe, Faust

One of the effective ways to analyze the structure of matter is to allow an energetic charged particle to collide into a solid target, or into another energetic charged particle. Studying the debris of the collisions is a very effective way to learn about the nature of the particles of matter. Charged particles can acquire the required for collision kinetic energy in acceleration process “falling” through potential difference or centripetal acceleration in magnetic field. Since it is difficult to establish necessary potential difference for higher energy particles, a charged particle can accelerate in magnetic field with periodic electrical boost (~100 keV per revolution). The device cyclotron is a particle accelerator that uses magnetic field to hold charged particle on circular orbit so that the modest accelerating potential can act on it rapidly, resulting in high energies. The frequency of circulation of the particle equals to the frequency of electrical oscillator.
q*B = 2 Pi* m* f. At proton energies above 50 MeV, cyclotron begins to fail; as the speed of charged particle begins to approach the speed of light, the frequency of the particle decreases. The required radius of dees is increasing greatly (for 500-GeV proton in B=1.5T, r = 1.1 km). A synchrotron avoids these difficulties: Both B and f are programmed to change cyclically. The particle acquires high energy (~1TeV in Fermilab synchrotron, ~20TeV in CERN ), going in constant orbital radius. Learn about different types of particle accelerators (cyclotron, synchrocyclotron, linac, synchrotron) and ways to detect/observe particles.
Compare different types of particle accelerators, provide analysis of methods used for accelerating particles, particles accelerated, energies achieved.

What kind of the basic research can be done using various types of particles accelerators (gold-foil alpha scattering, early cyclotrons, synchrocyclotrons, linacs, Tevatron, CERN LHC? Provide ranges of typical particle energies for each type of accelerator and resolving ability of the particles (de Broglie wavelength lambda = h / (mv)).

Explain why high-energy particles are effective tools for resolving the finer details of the working of atoms.

Radioactive Decay

“I have always looked upon decay as being just as wonderful and rich an expression of life as growth.” Henry Miller

Naturally occurring radioactive nuclides provide ways to estimate the dates of historic and prehistoric events. The concept of half-life is used to model the process of radioactive decay: the time required for one half of the particular type of radioactive nuclei to decay is constant. The approach is based on statistical analysis (decay of a nucleus is a random event). Rate of decay represents the radioactivity of the unstable nuclei and is calculated as a number of disintegrations per time interval. Activity is measured in decays per second, Bq (SI), Ci. The amount of radioactive substance after some time can be calculated using the model N = No (2) (-t/T); the activity of the substance A= Ao (2) (-t/T). Organic material can be dated by measuring their 14C content, rock samples can be dated analyzing radioactive 40K. Learn about radioactive decay and answer the following questions.

Radiometric dating has helped to determine that life has appeared on Earth approximately 3 billion years ago. Describe how you would estimate this.

A chunk of carbon, assumed to be ashes from an ancient fire, has activity of 89 Bq. The initial activity is estimated to be 105.4 Bq. Estimate the age of the sample.

The half - life period of a radioactive substance is 32 hours. After how much time will 6.25% of the radioactive material remains?

Four units are used to describe the exposure to ionizing radiation. The Curie measures the activity of the source. The roentgen is a unit of exposure. The Rads are used to measure the amount of energy absorbed. The Rems are units for measurement of biological effects of absorbed energy. Research the methods used in mining radioactive substances, such as uranium. What are the biological effects of exposure to radiation? Briefly describe some of the safeguards taken to protect the health of the miners.

Describe some medical of applications of radiation.