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)