serena barbanotti infn milano

Carlo PaganiUniversity of Milano and INFN Milano-LASA

High Power Accelerators for Very Intense Neutron Sources

International Workshop on Accelerator based Neutron Sources for Medical, Industrial and

Scientific Applications

Turin, Environment Park, 23rd May 2008

Presented by: Serena Barbanotti - INFN Milano-LASA

Int. Workshop on Accelerator Based Neutron Sources

Turin, 23 May 2008

Carlo Pagani & Serena Barbanotti 2

Index

Introduction: why accelerators as source for neutrons?– General principles of neutron production with accelerators

What is a high power accelerator and how does it work?– General layout– Superconductive choice

Applications of accelerator driven neutron sources– Waste Transmutation (ADS)– Materials studies (SNS)– Fusion (IFMIF)


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Why Accelerators

Easily pulsed beams

No chain reactions

Very high typical fluxes–A 1 mA beam delivers to the target 6·1015 particles per

second


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Accelerators and Neutrons

The accelerator

A particle accelerator is delivering energy to the beam via a rotational electric field acting on the charged particles.

Depending on the reaction chosen for neutron production, either proton or deutons are accelerated (high intensity simple particles with maximum charge to mass ratio).

Superconducting accelerators are preferred for their higher efficiency in the power conversion from plug to beam.


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The neutron source

High intensity charged particle beams are used to produce high intensity neutron fluxes for several applications

The neutron flux is determined by the charged particle flux through a simple nuclear process on a beam target (spallation or stripping reaction)

Different materials are chosen and different particles are accelerated, depending on power density, application, …


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Beam target choice

High Z materials for spallation → high efficiency neutron conversion

Liquid or solid, depending on power density– for good neutron economy is required to minimize target dimension– very high power density on target– liquid target are preferred (heat removal by convection)– solid target have power limit

Beam – liquid target interface: window or windowless ?

Window related problems:– window cooling– cyclic thermal loading on the window under creep condition– very corrosive environment (using lead)– radiation damage induced by proton and neutron in the window

material


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Neutron generation 1/3

Spallation reaction

– An heavy metal target hit by a high energy proton generates neutrons

• proton ~1 GeV → 20 - 30 neutrons

Characteristics:

• High conversion factor neutrons/protons• Wide neutron energy spectrum• For high neutron production efficiency, required high energy

proton beam


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Stripping reaction

– An incident deuton hits a Lithium target nucleus; the target emits a neutrons and the deuton proceeds with most of its original momentum in almost its original direction

– Typical reactions:7Li(d,2n)7Be 6Li(d,n)7Be 6Li(n,T)4He

Characteristics:

• Lower conversion factor• Peaked neutron energy spectrum: 14 MeV• Required low energy beam


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Spallation reaction

ADS

SNS

Proton beam


Stripping reactionIFMIF

Proton beam


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Applications 1/3

Nuclear fusion (IFMIF)

Fusion reactors will produce high neutron fluxes at 14 MeV

This will bring to high material irradiation

To guarantee reactor operation, required materials with:

– ITER: 3 dpa/lifetime

– DEMO: > 20 dpa/year

Required a material test facility for material verifications


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Applications 2/3

Nuclear Waste Trasmutation (ADS)

Problem: Disposal of Nuclear Waste

– Reduce radiotoxicity of the waste

– Minimize volume/heat load of waste

Strategy: Partitioning and Transmutation

– Separate chemically the waste (Pu, MA, LLFF)

– Use the waste as fuel in dedicated transmuter systems

Solution: a transmuter has 2 ingredients

– A subcritical reactor (k<1), with U-free fuel: chain reaction is not self-sustained

– An intense spallation source (high p flux on liquid lead target) : provides “missing” neutrons to keep the reaction going, with a broad energy spectrum (good for MA burning)


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Application 3/3

Material science (SNS)

Neutrons provide unique insight into materials at the atomic level:

– ‘see’ light atoms in biomaterials and polymers

– study magnetic properties and atomic motion

– measure stress in engineering components


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The accelerators

ADS SNS IFMIF

Accelerates protons H-, converted in p at accumulator ring

deutons

Neutron production

Spallation on liquid lead/bismuth

Spallation on liquid mercury

Strippingdeuton - Litium

Target area Windowless With window With window

Neutron energy Wide spectrum Wide spectrum 14 MeV

Beam dimension ~ dm2 ~ dm2 ~ dm2

Beam energy ~ 600-1000 MeV ~ 1 GeV ~ 40 MeV

Average beam current

20-40 mA 1.4 mA 2 * 125 mA

Total beam power ~ 20 MW 1.4 MW 10 MW

Beam operation Continuous Pulsed: 60 Hz – 695 ns Continuous


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Index





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Particle Accelerators

The name Particle Accelerator is a historical one connected to the concept of an energy increase related to a velocity change, that is an acceleration.

For protons and ions that has been the case for a while:

– Electrostatic accelerators

– Linacs

– Cyclotrons

Synchrotron concept and strong focusing scheme pushed energies to e level where the Energy increase is dominated by the particle mass increase and the velocity is very close to the speed of light.


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Basic Concepts: Fields

Equation of motion and Lorentz force– Electric field can transfer energy to the particles

– Magnetic field can guide the beam in a stable path

All Particle Accelerators are based on these rules– The beam moves inside a vacuum chamber– Electromagnetic objects placed on the beam path perform the tasks:

• Magnets guide the beam on the chosen trajectory (dipoles) and provide focusing (quadrupoles)

• Resonant RF cavities (exceptions: Betatron, RFQ and Electrostatic Accelerators) are used to apply the electric accelerating field

magelLorentzem FFBvEqdt

pdFF

)(

dtvEqsdFTE em FieldElectricE

EnergyCineticT

GainEnergyE


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Some Milestones for Accelerators

20th centuryfirst 25 years

from 1928to 1932

1928

1929

1944

1946

1950

1951

1956

1970

early 80's

the last years

Prehistory: fundamental discoveries made with "beams" from radioactive source trigger the demand for higher energies

Cockcroft&Walton develop a 700kV electrostatic accelerator based on a voltage multiplier

First Linac by Wideroe based on resonant acceleration

Lawrence invents the cyclotron

MacMillan, Oliphant & Veksler develop the synchrotron

Alvarez builts a proton linac with Alvarez structures (2 mode)

Christofilos patents the concept of strong focusing

Alvarez conceives the tandem

Kerst stresses in a paper the concept of a collider

Kapchinski & Telyakov invent the radio-frequency quadrupole RFQ

superconducting magnets for cylotrons and synchrotrons considerably boost the performance (energy for size)

the development of superconducting accelerating cavities provides very high power conversion efficiency


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Accelerators evolution: the Livingston chart

Around 1950, Livingston made a quite remarkable observation:

Plotting the energy of an accelerator as a function of its year of construction, on a semi-log scale, the energy gain has a linear dependence.

50 years later, that still holds true.

In other words, so far, builders of accelerators have managed exponential growth, every ten years, roughly a factor of 33 is won.

Note that for a given "family" of accelerators, saturation of maximum energy sets in after some time.

future

E = m c2


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An RF source generates an electric field in a region of a resonant metallic structure; the particles of the beam need to be localized in bunches and properly phased with respect to the field so that the beam is “accelerated”

Two possible designs:– NC Travelling wave structures– SC Standing wave cavities

Linac RF acceleration concept

mode

Traveling waveVph ≈ c and Vg < c

Standing waveVph = 0 and Vg = c

bunches Electric field


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RF Linac Overview

Particle Source

Linac structure:

Acceleration (cavities)Transverse focusing (magnets)

Electric power

Vacuum

Cooling

RF powerand controls

Output beam (experiments, users,

applications ...)

Subsystems

SNS - ORNL

TTF - DESY


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Energy gain and dissipated power

To accelerate particles efficiently, very high electric field is required

In any structure (cavity) holding an electromagnetic field, both dissipated power and stored energy scale quadratically with the fields

The efficiency of a cavity depends from:

Its quality factor, Q

driven by the surface resistance, Rs

Its shunt impedance, rfunction of the cavity geometry

and of the surface resistance, Rs

For efficient acceleration Q, r and r/Q must all be as high as possible

dtvEqsdFTE Lor

dissP

UQ

dissP

Vr

2

U is the energy stored in the cavity

Pdiss is the power dissipated on its surface

ΔV is the voltage seen by the beam

U

V

Q

r

2 “r over Q” is purely

a geometrical factor

Good material for maximum Q and r (that is minimum Pdiss)

Good design for maximum r/Q

L R C


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Why Superconductivity in RF linacs?

In normal conducting linac a huge amount of power is deposited in the copper structure, in the form of heat, that needs to be removed by water cooling (in order not to melt the structures)

– Dissipated power can be much higher than the power transferred into the beam for acceleration

Superconductivity, at the expenses of higher complexity, drastically reduces the dissipated power and the cavities transfer more efficiently the RF power to the beam

In short:– NC linac: lower capital cost, but high operational cost– SC linac: slightly higher capital cost, but low operational cost


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Superconductivity whenever possible

For a good but not perfect conductor (ρ ≠ 0), the fields and currents penetrate into the conductor in a small layer at the cavity surface (the skin depth, δ)

With RF fields, a SC cavity dissipate power, not all electrons are in Cooper pairs.

In NC linac a huge amount of power is deposited in the copper structure: MW to have MV

– Pulsed operation and Low Duty Cycle

SCSuperConducting

NC or RTNormalConducting

0

sR

S

sdiss dSH

RP 2

2

K

664.17exp

K

GHz109n

24

TT

fRs

GHz8.7m 2

1

fRs

Nb

Cu

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

0 500 1000 1500 2000 2500 3000

f [MHz]

Rat

io b

etw

een

Nb

an

d C

u R

s

2 K4.2 K


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Superconductivity whenever possible

Superconductivity, drastically reduces the dissipated power. But some drawbacks

– Higher complexity: refrigeration and cryomodules• Carnot and refrigeration plant efficiencies

– Higher technology: cavity treatments– Simpler geometries: lower shunt impedance

And two big advantages:– Large bore radius: less beam losses– CW or high duty cicle preferred

K2,K300for150/1

K2.4,K300for70/1

21

21

21

2

TT

TT

TT

TC

K2at1WforK300atW800

K2.4at1WforK300atW250

T

TthCtot

K2at%2015

K2.4at%3025

T

Tth


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Index





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ADS proton beam requirements

Very high duty cycle, possibly CW

Energy of the order of 1 GeV, determined by– neutron production rate per GeV

and per proton(optimum value reached at ~1 GeV)

– energy dissipated in the input window(rapidly decreasing with energy, when E<few GeV)

beam power from several MW up to tensof MW

– few MW for a “demo” plant of ~100 MWth– ~20 MW for an industrial burner of ~1500 MWth

Very few beam trips per year accepted if longer then 1 second

No limitation for very short beam trips: << 1 second

0

10

20

30

40

50

0 0.5 1 1.5 2 2.5

yiel

d / E

p (n

eutro

ns/G

eV)

proton energy, E_p (GeV)


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The proton linacs


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Linac or cyclotron 1/2

Most powerful CW proton accelerators (MW-size facilities)

Linacs– LAMPF/LANSCE (~1970)

• 800 MeV• 1 mA H+ average current • Peak H+ current 16.5 mA @ 100 Hz and 625 s pulse length• NC accelerator

Cyclotrons– PSI – separated sector (1974)

• Original design was for 100 A• From 72 to 590 MeV• ~2 mA average current• Beam losses at extraction < 1 A


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Linac or cyclotron 2/2

Cyclotron

No remarkable R&D programs

Its cost scales quadratically with the output energy

Very high reliability and availability at PSI, but further improvement looks very difficult

Not applicables concepts of redundancy and spare on line

Linear Accelerator

A worldwide R&D effort is in progress

High potentiality of these machines has been proven:– Sources, RFQs and SRF technology successfully operated

cost per MeV is decreasing with energy

Linac (except front end) has intrinsic modularity:– Easy redundant and “spares on line” design


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The ADS Linac

Linac benefits of impressive progresses in the field of SC cavities:

– SC technology can be extended to proton linac down to ~ 0.5

Intrinsic modularity simplify reliability issues

– Redundant design strategy based on the “spare-on-line” concept

– Strong focusing and large beam aperture produce negligible losses

The scheme generally considered consists of four different sections

– The proton source: proton energy 80-100 keV– The Radio Frequency Quadrupole (RFQ): up to 5 MeV– A medium energy section, either NC or SC: up to 100 MeV– A high energy section made of SC elliptical rf cavities: up to final

energy 1 GeV (most of the linac is here!)


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Reference Linac Design

Source RFQ ISCL High Energy SC Linac

Microw

ave RF

Source

High current (35 m

A)

80 keV

High transm

ission 90%

30 mA

, 5 MeV

(352 M

Hz)

5 - 85/100 MeV SC linac

Spoke cavities (352 MHz)

Lambda/4 cavities (176 MHz)

Reentrant cavities (352 MHz)

or

NC Drift Tube Linac (DTL)

3 section linac:

– 85/100 - 200 MeV, =0.47

– 200 - 500 MeV, =0.65

– 500 – 1000/2000 MeV, =0.85Five(six) cell elliptical cavities

Quadrupole doublet focussing: multi-cavity cryostats between doublets

– 704.4 MHz

Proton Source

RFQ Medium energy ISCL linac 3 sections high energy SC linac

80 keV 5 MeV ~100 MeV 200 MeV 500 MeV >1000 MeV


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Linac Design

Accelerator design performed in the EU PDS-XADS program (5° FWP)– Choice of superconducting linac– Modular: same concept for Prototype and Industrial scale


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Injector, an example: LEDA at LANL

LEDA RFQ:

Beam current 100 mA (95 %)

Final Energy 6.7 MeV

Length 8 m (4 sections)

RF Power670 kW (beam)

1.2 MW (structure)

RFQ Concept

One Section of LEDA-RFQ

The LEDA-RFQ fully installed

magelLorentz FF)BvE(qdtpd

F


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High energy section: the test module

Elliptical =0.47 cavities have been produced, vertically tested and will be equipped to be tested in an horizontal test module by INFN - LASA

0 2 4 6 8 10 12 14 16 18 20109

1010

start of electron emission

Q0

Eacc

[MV/m]

Z501 Test #1 Z502

Eacc

=8.5 MV/m @ Q0=1010

multipacting barriers


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The Reliability Issue

The small number (few per year) of beam trips allowed during the accelerator operation, requires a detailed analysis of the accelerator availability and reliability, much deeper that in the past applications

The reliability analysis of a complex system is an iterative process, which starts from a preliminary design of the whole system and its components and is followed by the development of the Reliability Block Diagram (RBD).


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Some Remarks on Linac Reliability

In order to meet the # of stops > 1 s– The beam startup procedure for a multi MW beam will be certainly > 1 s

operation with faulty components needs to be achieved • Linac must tolerate single failures of most of components• Procedures for “adjusting” beam transport and repairing of components

without interrupting the beam while marinating acceptable lossesAs a consequence– Components and subsystems divided in two major categories if they lead to:

• Failures requiring a beam stop• Failures that can be repaired while the beam is on, or later…

As general rules– Components falling in the first category should have the highest reliability

• Typically passive components overdesigned and overtested – Components falling in the second category should have the highest

accessibility for repairing or substitutionFor example, this suggest the choice of a double tunnel design, with most of ancillaries situated in a free-access tunnel (Power supplies, RF generators, etc.)


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Index





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SNS Guiding Principles

SNS will provide high availability, high reliability operation of the world’s most powerful pulsed neutron source

Research conducted at SNS will be at the forefront of biology, chemistry, physics, materials science and engineering

– SNS will be able to provide cold neutrons (useful for research on polymers and proteins)

SNS expects 1000-2000 users per year from academia, government, and industry

Flexible instrument strategy that supports both general user access and dedicated access for expert instrument teams that contribute to construction and operation of instruments


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The Spallation Neutron Source


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Neutron generation

H- ions are produced in the front end ion source

H- are accelerated to ~1GeV in Linac (NC and SC)

On injection into ring 2x e- are stripped to form p

Protons are accumulated and compressed into a 1 µs pulse width in the ring (~120 turns of the ring, p are traveling at ~0.9c)

A kicker magnet knocks the proton pulse out of the ring orbit into the beamline that takes the p’s to the Hg target

Beam losses need to be preserved below 1 W/m along the whole machine and beamlines to limit activation


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Power Ramp-up Progress

“We are starting to get to real beam power levels”

160 KW: ISIS Power Record


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Beam Target and Neutron Moderation

Spallation target

Mercury was chosen for the target for several reasons

– it is not damaged by radiation, as are solids

– it has a high atomic number, making it a source of numerous neutrons (the average mercury nucleus has 120 neutrons and 80 protons)

– because it is liquid at room temperature, it is better able than a solid target to dissipate the large, rapid rise in temperature and withstand the shock effects arising from the rapid high-energy pulses

Neutron moderation

The neutrons coming out of the target must be turned into low-energy neutrons suitable for research

– moderated to room temperature or colder passing them through cells filled with water (to produce room-temperature neutrons) or through containers of liquid hydrogen at a temperature of 20 K (to produce cold neutrons)

– The moderators are located above and below the target


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805 MHz, 0.55 MW klystron

805 MHz, 5 MW klystron

402.5 MHz, 2.5 MW klystron

Layout of RF Linac

SRF, ß=0.61, 33 cavities

1

from CCL

186 MeV

86.8 MeV2.5 MeV

RFQ

(1)

DTL

(6)

CCL

(4)

SRF, ß=0.81, 48 cavities

1000 MeV

(81 total powered)

379 MeV

Warm Linac

SCL Linac


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Normal Conducting Linac

CCL Systems designed and built by Los Alamos

805 MHz CCL accelerates beam to 186 MeV

System consists of 48 accelerating segments, 48 quadrupoles, 32 steering magnets and diagnostics

402.5 MHz DTL was designed and built by Los Alamos

Six tanks accelerate beam to 87 MeV

System includes 210 drift tubes, transverse focusing via PM quads, 24 dipole correctors, and associated beam diagnostics


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Superconducting Linac

Designed an built by Jefferson Laboratory

SCL accelerates beam from 186 to 1000 MeV

SCL consists of 81 cavities in 23 cryomodules

Two cavities geometries are used to cover broad range in particle velocities

Cavities are operated at 2.1 K with He supplied by Cryogenic Plant

Medium beta cavity High beta cavity


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Others SNS Parameters

Protons per pulse on target 1.5x1014 protons

Energy per pulse on target 24 kJ

Average linac macropulse H- current 26 mA

Linac beam macropulse duty factor 6%

Front end length 7.5 m

Linac length 331 m

HEBT length 170 m

Ring circumference 248 m

RTBT length 150 m

Ion type (Ring, RTBT, Target) proton

Ring filling time 1.0 ms

Ring revolution frequency 1.058 MHz

Number of injected turns 1060

Ring filling fraction 68%

Ring extraction beam gap 250 ns

Maximum uncontrolled beam loss 1 W/m

Number of ambient / cold moderators 1/3

Number of neutron beam shutters 18


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SNS Instruments


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SNS Reflectometers

Rmin< 5×10-10

Qmax ~ 1.5 Å-1 (Liquids)

~ 7 Å-1 (Magnetism)dmin~ 7 Å50-100× NIST NG-1

Magnetism: vertical sample

Liquids:horizontal sample


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Diffraction

• Highest flux a short wavelengths is crucial for studies of local disorder in complex materials

• Nanoscale Ordered Materials Diffractometer (NOMAD)


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High Pressure Cells Limit Sample Volume

• Pressure cell of the type to be employed on SNAP (Spallation Neutrons and Pressure) beamline


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Index





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IFMIF general information

IFMIFIrradiation tool to qualify advanced materials resistant to extreme radiation conditions (DEMO reactor)

Requires an intense neutron flux (~1017 n/s/m2) at 14 MeV

Neutrons are generated by stripping deutons on Li target. Deuton provided by accelerator: 2 parallel CW beams 40 MeV, 125 mA for a total power of 10 MW

IFMIF-EVEDA (Engineering Validation Engineering Design Activities)Engineering design of the IFMIF facility, safety assessment for a generic site and preparation of the technical specifications for the longest delivery components

Design and construction of low energy section of the first accelerator

Design, construction and tests of a scale 1:3 model of the Target Facility

Design, construction and tests of mock-ups of the Test Facility (high flux volume and medium flux volume). Irradiation of the test set-up to relevant irradiation dose values to check performance under real operating conditions


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ITER

3 dpa/lifetime

DEMO

30 dpa/year

IFMIFIFMIF

20-55 dpa/year

Advanced Materials are at a critical path


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neutron flux

coolant flow (He)

200

50

50

[mm]

IFMIF Main Objectives

Neutron flux: 10 MW deuton beam power on the test module is equivalent to

– 1 MW/m2 neutron beam– 4.5 1017 n/m2/s– 3 10-7 dpa/s for Fe

Neutron spectrum: fit to probable DEMO first wall

Neutron fluence accumulation:DEMO relevant (150 dpa/few years)

Neutron flux gradient: about 10 % in volume

Machine availability: 70 % (quasi continuous operation)

Good accessibility of irradiation volume for experimentation and instrumentation


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Accelerator (x 2) Test Cell

IFMIF Principles

Low flux (< 1 dpa/an, > 8 L)

Medium flux (20 – 1 dpa/an, 6 L)

RFQ HWR HEBT

Typical reactions– 7Li(d,2n)7Be– 6Li(d,n)7Be– 6Li(n,T)4He

Source

Lithium target

High flux (> 20 dpa/an, 0.5 L)


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IFMIF “Artist View”

Ion Source

RF Quadrupole

Post Irradiation ExperimentFacilities

High Energy Beam Transport

Li Target

Li Loop

Test Modules insideTest Cells

Half-wave resonators

0 20 40 m


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IFMIF Accelerator

A high intensity ion source, delivers a beam of deutons of 140 mA to 100 keV

A RFQ (Radio Frequency Quadrupole) cavity put « in packages » and accelerate the deutons until a 5 MeV energy

Elements of linear accelerator to reach the final energy (10 MeV at EVEDA, 40 MeV at IFMIF)

A transport line up to the beam stop of 1,2 MW for EVEDA phase and up to the liquid lithium target of 10 MW for IFMIF


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~ ~

Accelerator Prototype (scale 1:1)

Ion Source

RadioFrequency Quadrupole

Matching Section

Half Wave Resonators linac

HEBT and Beam Dump

Building (at Rokkasho)for the test of the accelerator

Lithium Loop (scale 1:3)

Diagnostics

Erosion/Corrosion

Purification system

Remote Handling

High Flux Test Module (HFTM)

Irradiation in fission reactor

Validation of sample concepts

IFMIF EVEDA design


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Accelerator Reference Design

High Energy Beam Transport (HEBT)Large Bore Quad & Dipoles, 43 m long

SC Half-wave resonatorsacceleration to 40 MeV

Radio Frequency Quadrupole (RFQ)bunching & acceleration 5 MeV; MS to DTL

RF Power System 175 MHz12 RF amplifiers, 1MW CW

100 keV

Injector Ion Source 140 mA D+, 100 keVLEBT transfer/match to RFQ

5 MeV

40 MeV

125 mA deuton beam

Control Command

22


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Injector - Conception

Specifications

rms emittance = 0.25 .mm.mrad (normalized )

beam current = 140 mA

energy = 100 keV

The injector components

the ECR (Electron Cyclotron Resonance) ion source must deliver 140 mA beam current with an output energy of 100 keV

the LEBT (Low Energy Beam Transport) section includes– magnetic lenses (focusing and beam matching to the RFQ)– beam instrumentation : charge, current, profile, size, emittance

measurement

the associated infrastructure: power supplies, control system, water cooling


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Injector – Initial LEBT design

Cone Cameras ACCT

Cameras

Neutron detector

Emittance Monitor

DC toroid on HV cable

Movable ConFlatSpecies identification*

Thermocouples*fluorescence + shifted Doppler lines analysis


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Radio-Frequency Quadrupole

• RFQ Length 9.6 meters

• RFQ transmission OK 99% (w/o error)

• Losses above 1 MeV kept at low level 0.01 %

• Voltage and Power levels moderate

< V > = 102 kV, P = 1200 1480 kW

RF study started

Cu brazing joints

e-beam & laser welding alternatives under study

Mechanical design in a test phase


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Old design: DTL and Matching Section

RF Frequency 175 MHz

Input energy 5.02 MeV

Output energy 9.02 MeV

Internal length 4.67 m

Internal diameter 1.074 m

Number of cells 33

Total power 680 kW

Power dissipation 180 kW

Efficiency 73.5 %

1st

tank

par

amet

ersConventional Alvarez technology

1 RF coupler / tank

Power coupler

Stem-box Cover

Tuning Slug

Post Coupler

Drift Tube Stem

Drift Tube

To vacuum pump

Bulk Tuner


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Present design: Half-wave resonators (HWR)

IFMIF/EVEDA Project Committee meeting (10-11 October 2007)Accelerator Facility Project Plan65

Superconducting solution: existing modules

SARAF* project SC IFMIF

Take 175 MHz HWR with big aperture 30 mm 40-50 mm

and conservative gradients 5.5 MV/m 4.5 MV/m

group cavities in long cryostats 6 8-10-12

module double of the onecurrently operating at SOREQ

L~ 5 m


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Lithium target

Engineering design of the target system includes thermal, thermo-structural and thermo-hydraulic analyses of the target assembly, backplate, Li components, Li loop and purification system

Quench Tank

Deuteron BeamsLi Target(T2.5 cm, W26 cm)

EM Pump

HX(Li / Organic Oil)

Dump Tank(9 m3-Li)

HX(Organic Oil / Water)

130 L/s, 250 C

Cold Trap(220 C)

N Hot Trap(600 C)

T Hot Trap(250 C)

The Lithium circuitThe Lithium target


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2 m

D+

Medium FluxTest Modules

High FluxTest Module Low Flux

IrradiationTubes

LithiumTarget

Lithium Tank

Shield plug

Principle of Test Modules


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Upper internal flangeUpper reflectorLateral reflector12 rigs

Lower reflector

Helium inlet duct

Helium exit duct

HFTM VIT

MF-CF

MF-LBVMF-TR

Irradiation modules overview


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IFMIF Medium Flux Test Module

3 independentsamples

in creep fatigue


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Conclusions

Present and future large facilities are based to a large extent on the superconducting RF linac technology that has been pioneered for the High Energy Physics machines in the last decades

– LEP at CERN (e+e- collider with SRF cavities)– CEBAF at TJNAF (recirculated SRF linac)– TESLA and ILC (next generation linear colliders proposed for

precision physics in the Higgs sector after LHC discovery)

SNS moved from NC design to SC after project approval and during construction

Future facilities rely on SC linacs at even lower energies to benefit from SC technology

serena barbanotti infn milano

Technology

high neutron fluxes

high energy proton beam

high intensity neutron

neutron source high

target liquid target

beam target spallation

high power accelerator

high power density