Instrumentation
1
W. Udo Schröder, 2004
Instrumentation
2
W. Udo Schröder, 2004
Probes for Nuclear Processes
To “see” an object, the wavelength l of the light used must be shorter than the dimensions d of the object. (DeBroglie: p=ħk=ħ2p/ )lRutherford’s scattering experimentsdNucleus~ few 10-15 m
Need light of wave length l 1 fm, or an energy
2 2 2 22
2 2
4 2 2
2
2002 6 1.2
1
( ) , . ., :
200 2
2 2 2 1.8
80 10 1800
c MeV fmE pc kc GeV
fm
Massive m particle e g proton
k ck MeV fmpE
m m mc GeV
MeV fmMeV
GeV fm
Not easily available
Can be made with charged particle accelerators
Instrumentation
3
W. Udo Schröder, 2004
Program
• Particle Accelerators• Interaction of Radiation with Matter• Radiation Detection• Applications
Ion Source
Accelerator Target
Detectors
Instrumentation
4
W. Udo Schröder, 2004
Ionization Process
1. e- impact (gaseous ionization)
• hot cathode arc• discharge in axial magnetic field
(duo-plasmatron)• electron oscillation discharge
(PIG)• radio-frequency electrode-less
discharge (ECR)• electron beam induced discharge
(EBIS)
2. ion impact• charge exchange• sputtering
e-/ion beam
- +q-
discharge
-+q+
Instrumentation
5
W. Udo Schröder, 2004
Penning Ion Gauge (PIG) Source
Arc Power 200V, 2A
Extractor Power 10kV
Beam q+
BkG
-
-
+
+
-
Plasma
Extractor Electrode
Cathode
Cathode
Anode
Assembly placed within magnetic field B.
Secondary e- emission from cathode oxide layers
j+ ~ 10-50 mA extracted beam
More efficient ion sources use microwave radiation to produce highly ionized plasma Electron Cyclotron Resonance (ECR)source
Instrumentation
6
W. Udo Schröder, 2004
LBL-88” Cyclotron PIG Ion Source
Hinged assembly swings between the poles of the cyclotron magnet.
Extraction slit
Instrumentation
7
W. Udo Schröder, 2004
Electron Cyclotron Resonance Source
Instrumentation
8
W. Udo Schröder, 2004
Duoplasmatron Ion Source
High ion density 5.1014/cm3, 10-2T, B~10T, j+~ 1A
Instrumentation
9
W. Udo Schröder, 2004
Electron Cyclotron Resonance Source
No electrodes, magnetic bottle, microwave power 10GHz, 1-2kW, high charge states
Instrumentation
10
W. Udo Schröder, 2004
Generation and Selection of Ions
Ions produced in the source can leave through extraction channel
Desired ion species selected by deflection magnet with adjustable field.
Transfer of slow ions to accelerator
GasCarrier Gas
Instrumentation
11
W. Udo Schröder, 2004
Next: Acceleration of ionized particles
Instrumentation
12
W. Udo Schröder, 2004
Injection and Acceleration
Transfer to accelerator
Acceleration
Injection (axial)
Ion trajectory (cyclic)
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