Accelerators and detectors Flashcards
What are the big questions in particle physics?
Unification
CP violation
Neutrino mass
Dark sector
Gravity
What is the probability of an electron/photon passing through a sheet of a material?
P(x)=e^(-x⁄X_0 )
Where X_0 is the radiation length
What is the probability of a hadron passing through a sheet of a material?
P(x)=e^(-x⁄λ_I ) where λ_I is the “Nuclear radiation length”
What is the radius of a particle in a magnetic field?
r=mv/qB
What is the cyclotron frequency?
f=qB/2πm
What is a LINAC?
A linear accelerator where a charged particle is accelerated through a series of stages via ana electric field
What energies can a LINAC reach?
1-100 GeV
What are the benefits of a LINAC?
Easy to build
Can accelerate electrons to reasonable energies without power loss
What are the drawbacks of a LINAC?
Don’t get to high energy without lots of acceleration
Diminishing returns for relativistic speeds
Long so require lots of land
What is a cyclotron?
Essentially a rolled up LINAC
Utilises a magnetic field and accelerates via an electric field across a gap
What are the benefits of a cyclotron?
They are cheap
Don’t need as much land as a LINAC
What are the drawbacks of a cyclotron?
Relies on the equal time assumption so difficult to accelerate to relativistic speeds
What is a synchrotron?
The inverse of a cyclotron
particles are accelerated at a constant radius with a varying magnetic field
What is the energy loss for a synchrotron?
Energy loss=ΔE=(E/m)4*1/r
1/r: higher energy loss for small radius so need big machines
(E/m): very inefficient to accelerate electrons in a synchrotron
What are the drawbacks of a synchrotron?
Particles lose energy as they go around the ring
What are the benefits of a synchrotron?
Great for high energy beams
What does a basic detector consist of?
Central tracker
Electromagnetic calorimeter
Hadronic calorimeter
Muon detector
What does the central tracker do?
Detects and tracks charged particles close to the interaction point
What does the ECAL do?
Measures electron and photon energies form how they move through the material
What does the HCAL do?
The same things as an ECAL but for hadrons
What does an electromagnetic shower consist of?
e-/e+/photon
What does a hadronic shower consist of?
Consists of other hadrons
