Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge...

54
December 12, 2018 1 Discovery, accelerated Accelerators at TRIUMF - Overview and developments Oliver Kester ALD accelerator division TRIUMF student lecture

Transcript of Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge...

Page 1: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

December 12, 2018

1

Dis

co

very

,accele

rate

d

Accelerators at TRIUMF -Overview and developments

Oliver Kester

ALD accelerator division

TRIUMF student lecture

Page 2: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

2

Outline

• Basics of particle accelerators

• Radio Frequency

(RF)-accelerators

• Overview TRIUMF accelerator

facility and rare isotope production

• Driver acceleratorsCyclotron and e-linac

• Production, preparation and

acceleration of rare isotope

beamsISAC and ARIEL RIB beams

Page 3: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

3

What is a „particle accelerator“?

An accelerator is a device that uses electromagnetic forces to accelerate and guide charged particles.

THE ESSENTIALS:

• Particle source(electrons, protons, ions)

• Vacuum

• Electric field for acceleration

• Magnetic and/or electric fields for focusing and steering

• Controls

Page 4: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

4

Acceleration of charged particlesAcceleration a with an electric field E

for a particle with mass m and charge q

Kinetic energy

The kinetic energy of charged particles is measured in electron volts (eV)

1 eV is the energy a singly charged particle acquires when it moves through a potential of

1 Volt. 1 eV = e * (1 Volt) = 1.6022*10-19 J

A convenient unit for heavy ion acceleration is energy/nucleon

Em

qaamF

d

UqEqF ==== ,

d

kin kin

qE q U q E d Joule E U Q U eV

e= = = =

/Q

W U eV uA

=

Page 5: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

5

Charged particles in electromagnetic fields

BvqEqF

+=Right hand

rule

In electromagnetic fields, the Lorentz force F acts on a particle with the charge q with

E is the electric field, B the magnetic field. The electric field causes acceleration in direction of the field vector,whereas the magnetic field causes an accelerationperpendicular to the direction the particle moves:

In the magnetic field, v(t) is constant!

Fmagnetic can be used forbeam manipulation(bending and focusing)!

vBvqFmagnetic

tois ⊥=

Page 6: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

6

Electrostatic accelerator

+ -

Source

TargetHigh voltagegenerator

E-Field

example:

TV tube

vacuum tube

electron emitter

horizontal deflection

vertical deflection

Page 7: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

7

Van de Graaff accelerator

5 MV van de Graaf of HMI Berlin

Page 8: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

Basics of RF-accelerators

Page 9: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

9

Linear and circular accelerators

Use multiple passes through a small

number of cavities

For ions:• Cyclotron, Synchrotron

For electrons:• Microtron, Betatron

Use a single pass through a large

number of cavities

Structures for ions:• Wideroe, Alvarez and H-type structures

Structures for electrons: • Elliptical cavities

Circular Accelerators Linear Accelerators

Page 10: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

10

RF-accelerator I

Multiple use of the same alternating voltage

→ Wideroe principle!

Proof of the rf- acceleration principle by Rolf Wideroe 1928 in Berlin.

Frequency: 1 MHz

Electric Field = 25000 V

Page 11: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

11

RF-accelerator IIThe crucial innovation was the field-freedrift tubes, shielding the ions from the electric field whenever it reversed direction.

Note that the beam is non-continuous –a stream of short pulses – separated by theradio frequency period Trf

Time to travel from center of gap i to gap i+1is half of the rf-cycle time Trf.

Wideroe condition: 2 2 2

i rf i rf i rf

i

v T cl

c

= = =

accU

2 acci i

i

q iUv c

m

l i

= =

Page 12: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

12

Example: Wideroe rf-Linac

Page 13: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

13

Resonator / cavity

C RpLUo

"pill box cavity„ - most common cavity in ring accelerators!!

Transformation from a resonance circuit to a cavity

1

2f

C L=

Page 14: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

14

RF Cavities

• RF cavities are specially designed structures

with electrically conductive walls

• The cavity is sized to resonate at a particular

rf frequency and with a shape such that an

electric field is produced along the path of the

charged particle as it passes through the

cavity

• A small driving rf signal couples electro-

magnetic energy into the cavity to establish

the accelerating field.

• A resonator can sustain an infinite number of

resonant electromagnetic modes but only one

mode is used for acceleration ( )tqEtqEF cos)( 0==

Page 15: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

Overview TRIUMF accelerator facility and rare isotope production

Page 16: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

16

Primary beam driver:Cyclotron, 500 MeV, H-

Produces rare isotopes, neutrons and muons!

Isotope Separator and Accelerator facility -

ISACIsotope Separator Online (ISOL) facility

ISAC-I: Normal conducting-linac, 0.15-1.5 MeV/u

ISAC-II: Superconducting-linac, 5-15 MeV/u

Advanced Rare Isotope Laboratory - ARIELSuperconducting electron linac

30 MeV, 10 mA, cw

4 Cyclotrons for medical isotope production500 MeV

Cyclotron

ISAC-IIHigh energy

ISAC-ILow and medium energy

ARIEL

Cyclotronsfor medical

Isotopeproduction

TRIUMF accelerator complex

Page 17: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

17

TRIUMF will transition into ARIEL:

• Multi-user, multi-disciplinary RIB Facility

• Intense, clean RIB beams into ISAC

experiments:

– New 35 MeV superconducting electron linac

– New 100 kW electron beamline and target station

– New 50 kW proton beamline and target station

Cyclotron

ISAC

e-linac – 30MeV

Existing

ARIEL1.5

ARIEL 2

Advanced Rare Isotope Laboratory - ARIEL

Page 18: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

18

Production of rare isotopes

Ion Separation OnLine (ISOL)

Isotope/Isobarseparator

Thick, hotproduction target

Driveraccelerator

Experiment

Ion source

Post accelerator

Radioactive ion beam

Examples:

• TRIUMF

• ISOLDE

(CERN)

• GANIL

Projectile Fragmentation (PF) and stopped beams

Experiment

Re-accelerator

Radioactive ion beam

Heavy iondriver

accelerator

Thin productiontarget

Fragmentseparator

Gas cell stopper/

Ion guide

Examples:

• NSCL/MSU

• GSI

• RIKEN

Page 19: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

Driver accelerators –cyclotron and e-linac

Page 20: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

20• H- cyclotron as proton driver (multiple extraction at different

energies) for RIB production

• Proton at 500 MeV up to 100 mA (50 kW)

• Two production lines:

• ISAC BL2A existing

• ARIEL-II BL4N expected 2022/23

The 520 MeV H--cyclotron

Largest Cyclotron in the world:D = 18 m

Magnet weight 4000 t

Coil current:18500 A

Page 21: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

21

Visitors in the cyclotron

Page 22: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

22

The cyclotron - principle

Cyclotron frequency

Bm

q

r

vc ==

qvBr

mv=

2

RF-amplifier

Invented by Ernest O. Lawrence in 1932

The particles are held to a spiral trajectory by a static

magnetic field and accelerated by an RF-field.

Page 23: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

23

The cyclotron technical implementation• Ions are injected in the center of the cyclotron.

• The electrodes can be excited at a fixed rf frequency – the cyclotron frequency.

• The particles will remain in resonance throughout acceleration, running “isochronous” and a

new bunch can be accelerated on every rf voltage peak (like in a linac).

• “continuous-wave” (cw)

operation

Page 24: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

24

Cyclotron historyBelow the 27-inch cyclotron,

Berkeley (1932). The magnet

was originally part of the

resonant circuit of an RF current

generator used in

telecommunications.

In late 1930, Lawrence’s student, Stanley Livingston, built a

“4-inch” version in brass. Clear evidence of magnetic field

resonance was found in November, and in January 1931

they measured 80-keV protons. Ions were produced from

the residual gas by a heated filament at the centre.

Page 25: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

25

Limits of the classical cyclotron

.))((0

constrBm

qzc =

=

Relativistic mass effect require a stronger magnetic

field at the outside of the cyclotron that the particle

stay in sync with the RF → isocyclotron

An outwardly-decreasing (negative-gradient) field ⇒vertical focusing.

Positive axial focusing requires B decreasing with r

→ provided naturally by B fall-off towards pole edge.

Solution to this problem:

The use of edge focusing to allow vertical focusing

and stay isochronous.

Page 26: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

26

Edge focusing

When a particle crosses a magnet end at an angle κ to the

normal, longitudinal components of the fringe field By interact

with velocity

components vx

parallel to the

edge, giving a

vertical force!

Kerst (1956)

suggested using

spiral sectors to

increase the

axial focusing

Page 27: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

27

Injection and extraction from a cyclotron

H- extraction

B

v

Carbon FoilH- Ion

p

NQ

A

Be

VNmR ou

=

12

-

N-3 N-2 N-1 N

septumshoe

Separation of turns:

Page 28: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

28

H- cyclotron has multiple

extraction ports.

The stripping foils can

be moved to different

positions and therefore

beams at different

energies can be

extracted.

The 520 MeV H--cyclotron

Page 29: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

29

Superconducting electron linac

To reach high energies with normal-conducting rf

cavities requires:

- very high power and usually pulsed operation;

- very long machines, as field strength is limited.

Superconducting cavities have been pursued

since ~1960 in the hope of reducing the power

dissipation in the walls to zero

→ complex infrastructure

Success came in the 70s and 80s using niobium!

Much higher electric fields can be produced with

those cavities – up to 50 MV/m.

Page 30: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

30

Electron Linacs

As an electron’s speed v → c (=1), the

speed of light, at relatively low energies

(~500 keV), the gap and pillbox cavity size

can be kept constant for the higher energies.

E-linacs are then built from identical sections

and cavities.

For higher energies and cw-operation

superconducting elliptical cavities are used

like the 9-cell niobium cavity (TESLA cavity)

for the FLASH free electron laser linac and

the European XFEL at DESY in Hamburg.

Page 31: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

31

ARIEL – superconducting electron-Linac• E-gun delivers max. 10 mA at 300 keV beam

• The injector cryomodule accelerates to 5-10 MeV

• The accelerator cryomodule is equipped with

two cavities and reaches max. 30 MeV.

E-gun

Injection

cryomoduleAcceleration

cryomodule

Page 32: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

32

ARIEL – electron-Linac modules

• Elliptical cavities,

1.3 GHz

• 9 cell,

TESLA type

• 11 MV/m

demonstrated

Cryo modules

(FUTURE)Klystrons

Page 33: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

Production, preparation and acceleration of rare isotope beams

Page 34: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

34

ISAC at TRIUMF

Isotope Separation and Acceleration facility (ISAC)

• Isotope Separation On Line (ISOL) facility for rare isotope beam (RIB) production

• Highest power driver beam(50 kW)

• Most intense radioactive beamof certain species: 11Li yield at2.2·104 ions/s with 65 mA(April 2015)

Page 35: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

35

Target ion sourcesOberflächenionisation Plasmaquelle mit heißer Transferlinie

Plasmaquelle mit

kalter Transferlinie

Surface ionisation Plasma ion source

• Target and ion sources units,

common is surface ionisation, laser

ionisation and plasma ionisation

• Targets are heated up to high

temperatures to support diffusion of

isotopes into the ionisation region

Page 36: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

36

Isotope extraction

• Simulation of the path of one Ga atom

produced in a Ta-foil target towards the

ionizer (on the left)!

• Extraction times vary significantly

between elements. Driven by volatility

and in-target chemistry

Page 37: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

37

• Two underground target stations with

extraction voltage up to 60 kV

Target module sits in a big vacuum

tank!

• Proton beam sent to one of the target

stations at the time

• Common pre-separator inside the

shielded area

• Mass separator on high voltage

platform (typical operation resolving

power 3000)

• Charge breeder (ECR type) for post

acceleration

Target stations and Mass separator

Page 38: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

38

ISAC Target Modules (TM)

TRIUMF employs so-called Target

Modules (TMs).

• Common are the different section of the

module, the service cap, service tray and

sources tray.

• TM is moved from the target station to the

hot cell for target exchange

• Target/Ion sources unit mounted on the

sources tray

Source cap Service tray Source tray

Service cap Service tray Source tray

Page 39: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

39

Beam delivery: Mass separation and charge state breeding

A/q-

analyzer

charge

state breeder

Low energetic

1+ ions

Low energetic

q+ ions

Post accelerator

or experiment

Analyzing

magnet

Buffer gas

emittance cooler

Switch

yardIsotopes from 1+

ion source

Mass separation by a high resolution

separator

(resolution of ARIEL-HRS ~20000)

Charge breeding =

Generation of highly charged ions

from externally injected

singly charged ions

in a high charge state

ion source:

Electron beam ion source (EBIS)

or

Electron Cyclotron Resonance

Ion Source – (ECRIS).

Page 40: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

40

separation

of rest gas ions

singly

charged

ions

n+ ions

solenoid

coils

Magnetic field confinement

RF injection

Electron Cyclotron Resonance ion source (ECRIS) charge state breeder

Microwave

Injection

Hexapole (Radial Magnet ic Field)Beam

ExtractionfB= 28B[T] (GHz)

Axial

B fieldc= qB/mCyclotron Frequency

Beam born in Magnetic field !

Microwave

Injection

Hexapole (Radial Magnet ic Field)Beam

ExtractionfB= 28B[T] (GHz)

Axial

B fieldc= qB/mCyclotron Frequency

c= qB/mCyclotron Frequency

Beam born in Magnetic field !

• Resonant microwave plasma heating

• Electron energies – up to MeV via

electron cyclotron resonance

• Magnetic confinement

• Higher frequency (28 GHz)

Becr ~ f, Ion current ~ f2

1

2c

e

ef B

m=

Page 41: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

41

U(z)

Z

ionisation

extraction

drift tubes

solenoid

ion

beam

electron beam

anode

electron

collector

electron

repeller

barrier

electrode

• Electrostatic confinement

• Intense electron beam

(current density,

up to 104 A/cm2)

• Tunable electron beam

energy

• Storage capacity

~ trap length, electron

current

Electron Beam Ion Source/Trap (EBIS/T) charge state breeder

Charge development for

stepwise ionisation

1+

n+

Page 42: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

42

ISAC linacs overview IISAC-I:

• DTL normal conducting at 106.08 MHz:

– Separated functions

– Variable energy machine

– 150 keV/u ≤ E ≤ 1.8 MeV/u

– 2 ≤ A/q ≤ 7

• Radio Frequency Quadrupol (RFQ)

normal conducting at 35.36 MHz:

– 8m long split ring structure

– 153 keV/u, 3≤A/q≤30

Page 43: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

43

ISAC-I RFQ

Irf max

Vrf max

Page 44: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

44

ISAC-I drift tube linac (DTL)

• Mode produces transverse electric field that gets

transformed to longitudinal field through the drift tubes

supported alternately from two ridges

• Suitable for heavy ions from = 0.02 → 0.15

Page 45: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

45

H-type structure(TE110) Acceleration

• TE110 is a deflecting mode

(transverse E) but it can accelerate

by loading with drift tubes to create

on axis electric field

• We use the same mode in a rf

deflecting cavity for ARIEL (shown

below)

-

+ + + +- -- -

+

+ + + +- - - -

-

+

-

Page 46: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

46

ISAC linacs overview II

ISAC-II: Superconducting linac at

106.08 MHz:

– SC-Linac using quarter wave

resonators (QWR) with

= 0.057, 0.071, 0.11

– Max. energy range

6.5 MeV/u (A/q=6)

16.5 MeV/u (A/q=2)

– Cryomodules with 4, 6 and 8

QWR and one SC solenoid 9T

Page 47: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

47

ISAC linacs cavities and modules

Quarter Wave Resonators (QWR)

– TEM mode cavities can produce accelerating

voltages across a coaxial gap with variable gap

distance

– Inner conductor about the length of /4 (quarter

wavelength of the RF-el. magn. Wave)

Page 48: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

Production of rare isotopes with ARIEL

Page 49: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

49

Production of RIBs with electron beams

10 mA of 30-50 MeV electrons from the

superconducting e-linac (via the photo

fission process) yielding a range of

isotopes not available from proton

reactions and higher beam purity.

500MeV protons 50MeV electrons

Page 50: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

50

Required electron beam energy

• Converter made of high Z material, Au, W, Ta.

Thickness ~ 3.5 mm.

• Electrons MUST be stopped in low Z material Al.

• The number of fissions per second saturates

beyond 35 - 40 MeV beam energy.

Page 51: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

51

ARIEL electron target principles?

• An electron-to-gamma converter is required

because the direct power deposition

imposed by the 35 MeV electrons in a target

is unsustainable.

• The e-linac delivers 100 kW electron beam

with FWHM ≈ 1 mm → 1 MW/cm3 power

density inside of the converter, which is

unsustainable!

Consequence: The electron beam needs to

be scanned over a larger area and the

resulting power needs to be dissipated

electron-

beam

Page 52: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

52Accelerators are no miracles, but require a profound know-how and technologies!

Page 53: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

53

Student education and research

• Ion sources Plasma ion sources, high charge state ion sources

(Charge state breeders)

• Beam physicsIntense, space charge dominated beams (HL-LHC

beam-beam effects, electron linac, cyclotrons)

High level computer applications

• Target research and development –Material properties, ions source optimization

(plasma physics)

• Superconducting RF (SRF) and RFCavity design, cavity and cryo module technology

Surface properties (-NMR and m-SR investigations

and processing),

Digital low level RF technology

Page 54: Accelerators at TRIUMF · 2018. 12. 12. · Electron Cyclotron Resonance ion source (ECRIS) charge state breeder Microwave Injection Hexapole (Radial Magnetic Field) Beam f B = 28B[T]

54

Dis

co

very

,accele

rate

d

Thanks for your attention!

Follow us @TRIUMFLab

www.triumf.ca