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Three sessions for all detection schemes…..
• My Goal: This is a very large area of active research, with ~100 years of history from Roentgen & the Curies to present. I want you all to be able to tackle a modern experiment without getting too distracted / off-put by the “how”
• Three sessions IS NOT ENOUGH!!!! I’m purposefully ignoring:• Accelerators, reactors
• Relativistic effects
• Electronics / DAQ
• Statistics
How this’ll work
• We’ve a lot of material to cover. Too much.
• I’m a strong believer in “active learning”• 40-50 min of lecturing (with plenty of questions )
• 10-15 min of small group activity, working on some toy problems
• PLEASE ASK QUESTIONS!!!!
• Resources:• Knoll: Nuclear Instrumentation
• Krane: Nuclear Physics
The PlanTM
Day 1 – Nov 6• Radiation interaction
with matter• α, β, γ, n0 , SF decay
• Scintillators• Organic
• Inorganic
• Light detectors• PMT, MCP
• Examples at TRIUMF
Day 2 – Nov 15• Charge particles
counting w/ gas• Geiger-Mueller
• Prop. counters
• Semiconductors• Si detectors
• HPGe detectors
• Examples at TRIUMF
Day 3 – Nov 17• Manipulating matter
• E and B fields
• lasers
• Examples• Recoil separators
• Traps
• Potpourri• Active targets
• 0νν detectors
• HE calorimeters
Ionizing radiation’s interaction with matter
• Sources of ionizing radiation?• Accelerators and Reactors (& HE lasers)
• Multiple secondary sources
• Nuclear decay• α, β, γ, n0 , SF decay
Nuclear decay
• α
• β
• γ
• n0
• SF
Nuclear decay
“Heavy” charged ions
10 MeV / u, Zbeam= 6,7,8,10,18
“Heavy”, charged ions
• Bragg Curve
• Energy (E), range in matter (x), and timing (t) are all affected by straggling, which widen their distributions
Believing Bragg by Bethe-Bloch
Beyond heavy…
• e-
Photons and matter
Photons and matter
• Three regimes
n0 interactions
• Elastic collision with the nucleus• Capture cross section dependent
• Look for secondary forms of radiation
E deposited in matter
• So, at this point, we’ve covered a couple general ways to deposit E of our ionizing radiation into some material. Once it’s there, how can we detect it?
Scintillating
• What makes a good scintillator?
Scintillators
• Organic
• Inorganic
Efficiency of scintillation
Detecting Light - PMT
Detecting Light - MCP
Concluding remarks
Active scintillators @ TRIUMF
• DRAGON’s gas target
Active scintillators @ TRIUMF
• DESCANT neutron detectors
Exercise
1. Calculate the scintillation efficiency of anthracene if a 1.5 MeV alpha particle is stopped in the medium, which created 20,300 photons with average wavelength of 447 nm
2. Starting from the full Bethe-Bloch, derive the non-relativistic Bethe-Bloch from the lecture
3. An ion chamber with parallel plate electrodes, spaced 5 cm apart, is filled with methane up to 1 atm and operated at 1 kV. Knowing the W-value of methane (27.3 eV/ ion pair), calculate the maximum e collection time. (Might need to look up mobility of ions in electric field, gas)