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Practical Group
Teachers Lab
At
CERN
Jana Buresova
Marla Glover
Claudia Haagen-Schützenhöfer
Alexander Kraft
Teachers lab at CERN
•
•
•
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General concept
Demonstration
Equipment
Cost
Where should the lab be?
• It should be a fixed installation (room, lab,
etc…)
• Near Microcosm – First choice
• Near the Training Center – second choice
• Very near a Equipment Storage area
• Near a workshop area
Who should us it?
• It could become apart of existing teacher
programs( HST, workshops, visits, etc…)
• Create a program just to use for labs
– An extension of programs
– A follow-up program to existing programs
• Teachers with a class of students
– They would need to have passed a CERN
training program to run the equipment and
know and understand CERN procedures
What should the lab look like?
• Ideal
– Classroom with lab space and terminals
– Attached storage area
– Attached workshop
workshop
classroom
lab
storage
What should the lab look like?
• Next best
– Classroom with large demonstration area
– Presentation Equipment
– Storage nearby
Look at other particle labs
DESY – workshops for
students and teachers
in special lab
(experiments with
radioactivity, vacuum
and cosmic rays)
Also demonstrational experiments: Photoeffect,
Comptoneffect, Röntgenspectrum …
Look at the other particle labs
FERMILAB
Lederman Science Center
Look at the other particle labs
Fermilab
• Educational center for both students and teachers
• Workshops for students and pupils with hands-on
experiments
• Programmes not only about particle physics
• Wide offer of different types of visits (1-day to
1-week)
Equipment for
Teacher’s Lab to show:
I.
Structure of matter and basic
properties of elementary particles
II. Particle acceleration
III. Particle detection
Rutherford Experiment
• WHAT?
– Historic experiment to investigate the structure of matter
– Scattering
– -spectroscopy
• HOW?
– A beam of - particles is scattered against gold sheet.
– The intensity at different angles hints to structure of atoms.
• WHY?
– Investigate the internal structure of particles
– To understand early methods of determining properties
– Scattering (fixed target experiment) is a method to do
particle physics (particle production, detection …)
Millikan Experiment
• WHAT?
– Historic experiment to determine the charge of an
elcetron
– Electric field
– Measurement of e/m
• HOW?
– An electric field and gravity acts on charged oil
droplets at the same time in opposite directions.
– The elementary charge is determined from the
velocity of the oil-drop movement.
• WHY?
– Mass and charge are important particle properties
Stern-Gerlach Experiment
• WHAT?
– Historic experiment to prove the existence of electron spin
– Magnetic moment
– Directional quantization
• HOW?
– A beam of potassium atoms is deflected in a non-uniform
magnetic field because of the magnetic moment of the
atoms.
– Magnitude and direction of the magnetic moment of the
atoms are obtained by measuring the density of the beam.
• WHY?
– Electron spin and magnetic moment are important
properties of elementary particles
Zeemann Effect
• WHAT?
–
–
–
–
Quantization of energy levels
Electron spin
Bohr’s magneton
Interference of magnetic wave
• HOW?
– A cadmium lap is submitted to different magnetic flux
densities.
– The red cadmium line is splitted.
• WHY?
– Show basic properties of particles
– Methodology used in Cosmology
Electron spin resonance
What?
_ Energy quantum
_ Quantum number
_ Resonance
_ g-factor
Cathode Ray Tube
• WHAT?
– Linear propagation of electron beams
– Behaviour of electrons in electric fields
– Deflection of electrons in magnetic fields
(Lorentz-Force)
• HOW?
– Electrons are accelerated within electric
fields.
– The electron beam is deflected by
magnets.
Thomson’s experiment
• WHAT?
– Energy gain due to electric field
– Trajectory curvature due to magnetic field
(Lorentz)
– Properties of electrons (charge, mass)
• HOW?
– Electrons accelerated in an electric field and
enter a perpendicular magnetic field.
– e/m is determined from accelerating voltage,
magnetic field strength and radius of the
Electron beam diffraction
• WHAT?
– Material waves
– De Broglie equation
– Bragg reflection
– Calculation of electron velocity
• HOW?
– Accelerated electrons hit a polycrystalline layer of graphite.
– The interference pattern is displayed on a flourescent
screen.
• WHY?
– The wave-nature of particles plays a role in acceleration
– Scattering (fixed target experiment) is one method to do
particle physics
Superconductivity
• WHAT?
– Determine transmission temperature
– Meissner-Ochsenfeld-Effect
• HOW?
– The temperature of the superconductor is constantly
lowered.
– Temperature and resistance are measured in short
time intervals.
• WHY?
– Superconductors are important for the creation of
accelerators and detectors
Hall Effect
• WHAT?
– Strength of the magnetic field
– Magnetic moment
– Directional quantization
• HOW?
– A current carrying conductor is placed in a magnetic
field.
– A small transverse potential difference (Hall-voltage)
can be determined.
• WHY?
– Magnetic fields of a certain flux play an important role
in many steps of CERN experiments (acceleration,
detection ...)
Magnetic Nuclear Resonance
• WHAT?
– Strength of the magnetic field
– Magnetic moment
– Directional quantization
• HOW?
– Magnetic moments are aligned with an external magnetic
field and this alignment is perturbed by an electromagnetic
field.
– The response to the field by perturbing is what is exploited in
nuclear magnetic resonance spectroscopy.
• WHY?
– Precision measurement of magnetic fields is done by NMR at
CERN
Photoelectric Effect
• WHAT?
– Work function
– Photon energy
– Quantization of energy
• HOW?
– A negatively charged zinc plate on top of an electroscope
is illuminated with a high pressure mercury lamp.
– The zinc plate is discharged if there is no barrier
(plexiglass) in between.
• WHY?
– Excitation by collision and emission of photons afterwards
is one principle of measurement in detection
Myon experiences
WHAT?
– Measure properties of muons
– Observe decays
HOW?
– Cloud chamber (Workshop or Equipment)
– KamioCan (HST 2000)
– Experiments done by practical WorkingGroup
QUARKNET
• WHY?
– Usage of cosmic rays for calibration of detectors
Frank-Hertz Experiment (Neon)
• WHAT?
– Energy quantum
– Electron collision
– Excitation energy
• HOW?
– Accelerated electrons excite neon gas
electrons in a tube.
– The electrons in neon at upper states deexcite in such a way as to produce a
visible glow in the gas.
Electron Positron Spectroscopy
• WHAT?
– - - decay
– + - decay
– Positron
– Neutrino
– Resting energy
– Decay energy
– Relativistic Lorentz equation
• HOW?
– -radiation of unstable nuclei is selected on the basis
of its pulses in a magnetic transverse field using a
diaphragm system.
– The relationship between coil current and particle
energy is determined for calibration of the
spectrometer.
– And the decay energy of -transition is obtained in
each case from the - -spectra.
• WHY?
– Resting and decay energy are important properties of
particles
– Spectroscopy is an important analytical method
Cost
• Leybold Didactic Swiss-75,000chf
– Minus 10% discount-67,000chf
– Minus duplicates-59,000chf
• Phywe bid-113,000euros
• Room to negotiate
• Other sources of economy???
Electron Spin Resonance
• What?
– Magnus Effect/Magnetic Fields/Rotational
mechanics
– Resonance/Spin Resonance
• How?
– The magnetic moments align in the
permanent magnetic field.
– The perpendicular alternating field creates
excitation which results in the electrons
absorbing energy then releasing it when it
goes back to its ground state.
• Why?
– This will help students see how electron spin
is used in medicine and materials.