Topic 8- Nuclear and particle physics Flashcards
Describe the Rutherford Scattering experiment
Rutherford used a radioactive source to fire alpha particles at a very thin gold foil. Most particles travelled straight through, some were deflected by small angles, and some were sent straight back. This showed that most of the mass and charge is concentrated in the nucleus, and most of atom is empty space.
How do LINACs work?
Ions can be accelerated by electric fields in a LINAC. The AC current provides a constantly changing direction of field. The electrodes are spaced further apart in order to compensate for the increasing speed
What is thermionic emission?
When electrons are able to leave a metal, as they are heated up, an electric field can then be used to accelerate them into a beam.
How do cyclotrons work?
2 Oppositely charged dees.
The magnetic field in the electrode makes them follow a circular path, since it is perpendicular to their motion until they eventually leave the electrode
The potential difference applied between the electrode accelerates the ions across the gap to the next dee (since there is an electric field in the gap). In the next dee, the ions continue moving in a circular path within the magnetic field. The potential difference is then reversed so the ions again accelerate across the gap. This process is repeated as the particles spiral outwards and eventually have a speed large enough to exit the cyclotron
What is the main differences between a synchrotron and a cyclotron?
-Synchrotrons are able to very magnetic and electric fields to account for reletivistic speeds
-One loop instead of multiple
How do Geiger Müller tubes work?
Ionising radiation enters the tube, which is filled with gas. The radiation ionises the atoms, causing an electron and a positive ion to be attracted to the anode and cathode respectively. This causes a current.
What does a particle have to have to leave a trace in a bubble chamber?
Charge and mass
What charge do the electron neutrino, tau neutrino and muon neutrino have?
0
What charge do all fundamental leptons have?
-1
Place the fundamental leptons in order of mass (increasing)?
Electron, Muon, Tau
Whats the main difference between leptons and hadrons?
Hadrons are acted on by the strong nuclear force, Leptons cannot be affected by the strong force.
List all quarks with a charge of 2/3?
Up, Charm and top quarks -2/3
Down, Strange, Bottom- -1/3
What is a Baryon?
A triplet of quarks
What is a meson?
A quark and anti-quark pair
List the 4 exchange bosons, and what they exchange?
- Photon/EM
-W/Z Boson- Weak nuclear
-Gluon/ Strong nuclear
-Graviton/ gravity
