Town Meeting Espoo, 17.-20.9.2007 The objective of this task is to study the feasibility of a new...

Town MeetingEspoo, 17.-20.9.2007

The objective of this task is to study the feasibility of a new generation of devices with orders of magnitude greater capacity and throughput in order to accumulate, cool, bunch and purify the high intensity radioactive ion beams of EURISOL.+ Construction of the prototype for beta-beams(P10: Towards 60 GHz, high-intensity …, by L. Latrasse, LPSC Grenoble)

ISOL target 1+ ion source

1+ n+1+ high-resolution separator A/q separator

Accelerator

1+ n+ scenario for ISOL post-accelerators

EURISOL Beam Preparation & LayoutA. Jokinen

Department of Physics, P.O.Box 35 (YFL)

FIN-40014 University of Jyväskylä

Charge breeder

CERN – JYFL – LMU – MSL – INFN – CSNSM - LPSC

TASK9


Sub-1: EURISOL-HRS

(T. Giles, CERN)

Multiple multipolar dipoles

CorrectionsLarge dispersion


Sub-2:Ion cooling and bunching inlinear Paul traps (D. Lunney)


Present RFQ-devicesName Input Beam Input

EmittanceCooler Length R0 RF Voltage, Freq, DC Mass

RangeAxial Voltage Pressure Output Beam Qualities

Colette 60 keV ISOLDE beam decelerated to ≤ 10

eV

~ 30 π-mm-mrad

504 mm (15 segments, electrically isolated)

7 mm Freq : 450 – 700 kHz -- 0.25 V/cm 0.01 mbar He Reaccelerated to up to 59.99 keV with long. energy spread ~10 eV

LPC Cooler SPIRAL type beams Up to ~ 100 π-mm-mrad

468 mm (26 segments, electrically isolated)

15 mm RF : up to 250 Vp, Freq : 500 kHz – 2.2 MHz

-- -- up to 0.1 mbar --

SHIPTRAP Cooler

SHIP type beams 20-500 keV/A

-- 1140 mm (29 segments, electrically

isolated)

3.9 mm RF: 30-200 Vpp, Freq: 800 kHz – 1.2 MHz

up to 260 amu

Variable: 0.25 – 1 V/cm

~ 5×10-3 mbar He

--

JYFL Cooler IGISOL type beam at 40 keV

Up to 17 π-mm-mrad

400 mm (16 segmentes)

10 mm RF: 200 Vp, Freq: 300 kHz – 800 kHz

-- ~1 V/cm ~0.1 mbar He ~3 π-mm-mrad, Energy spread < 4 eV

MAFF Cooler 30 keV beam decelerated to ~100

eV

-- 450mm 30mm RF: 100 –150 Vpp, Freq: 5 MHz

-- ~0.5 V/cm ~0.1 mbar He energy spread = 5 eV, Emittance @ 30keV: from = 36 π-mm-mrad to

eT = 6 π-mm-mrad

ORNL Cooler 20-60 keV negative RIBs decelerated to

<100 eV

~50 π-mm-mrad (@ 20

keV)

400 mm 3.5 mm RF: ~400 Vp, Freq: up to 2.7 MHz

-- up to ±5 kV on tapered

rods

~0.01 mbar Energy spread ~2 eV

LEBIT Cooler

5 keV DC beams -- -- -- -- -- -- ~1×x10−1 mbar He (high-p

sect.)

--

ISCOOL 60 keV ISOLDE beam up to 20 π-mm-mrad

800 mm (using segmented DC wedge

electrodes)

20 mm RF: up to 380 V, Freq: 300 kHz - 3MHz

10-300 amu

~0.1V/cm 0,01 - 0,1 mbar He

--

ISOLTRAP Cooler

60 keV ISOLDE beam -- 860 mm (segmented) 6 mm RF: ~125 Vp, Freq: ~1 MHz.

-- -- ~2×10-2 mbar He

elong ≈ 10 eV us, etrans ≈ 10p mm mrad.

TITAN RFCT continuous 30–60 keV ISAC beam

-- -- -- RF: 1000 Vpp, Freq: 300 kHz - 3 MHz

-- -- -- 6 π-mm-mrad at 5 keV extraction energy

TRIMP Cooler

TRIMP beams -- 660 mm (segmented) 5 mm RF= 100 Vp, Freq.: up to 1.5 MHz

6 < A < 250

-- up to 0.1 mbar --

SPIG Leuven cooler

IGISOL Beams -- 124 mm (sextupole rod structure)

1.5 mm RF= 0-150 Vpp, Freq.: 4.7 MHz

-- -- ~50 kPa He Mass Resolving Power (MRP)= 1450

Argonne CPT cooer

-- -- -- -- -- -- -- -- --

SLOWRI cooler

-- -- 600 mm (segmented sextuple rod structure)

8 mm RF= 400 Vpp, Freq.: 3.6 MHz

-- -- ~10 mbar He --

Plenty of devices prototypedSimilar devices in size and operation parametersDifferent solutions for the combination of transversally confining RF-field and an axial potentialPerform very wellPoorly tested with very high intensities !


Next-generation RFQ for EURISOL

Technical proposalr by O. Gianfrancesco

(in terms of an ion beam/cloud capacity)

84 220

2 Vq

mr

eVD Mathieu

RF

10-100-fold increase in the capacity based on theincreasing of the pseudopotential depth D

Technical challenge to be solved: 20-30 MHz at 10 kV !10 A beam or cooled bunches of 6x109 ions at 100 Hz rate

(D. Lunney, Orsay)

e.g. A=40; 2x0=7 mm@ 2 MHz; V(q=0.4) = 80 V; D = 8 eV@ 20 MHz; V(q=0.4) = 8000 V; D = 800 eV

Town MeetingEspoo, 17.-20.9.2007 O. Gianfrancesco, Ph.D. thesis, McGill University (2005)

Radiofrequency: 10 kV beyond 10 MHz


Latest results (August 2007)

• Full-length cooler assembled

• 30-keV ion beam injected with an intensity of 1 microA and successfully transmitted (but with no gas cooling)

• Post-doc (O. Gianfrancesco) resigned…

• The test bench will be moved to LPC-Caen

• The tests will continue once an ECR source (with magnetic separation) is set up (fall 2007)

• Tests (and commissioning?) will be performed in the framework of a Ph.D. thesis (Florian Duval) for use at the SPIRAL-2 facility

• ISCOOL soon on-line at CERN ! (P6: Hanna Franberg)

Sub-3: Charge Breeding:Perspectives for EURISOL

• EURISOL– Intense beams up to 1013 ions/s (µA)– Superconducting LINAC (DC beams accepted)– Beam quality and purity

• EBIS– High performance charge breeder: high charge states, short

breeding times and good beam purity– Pulsed mode preferred– Limits in beam total currents

• ECR– Moderate performance charge breeder: comparatively low charge

states, high background– Continuous mode tested, both possible– High currents capabilities

(Presentation by O. Kester on Monday)


ECRIS EBIS/T

Single charge state breeding efficiencies

< 20% <30%<70% in principle

Beam purity Support gas and rest gasIn between peaks ~0.5-10 nA

Rest gas peaks 10-100 pA;In between peaks <<<1 pA (not detectable)

Beam particle rate limitations

> 1e12/s <1e9/s with pre-bunching<1e11/s with continuous injection

Breeding times 50 ms 10 ms

Typical A/q A/Q >5-6 A/Q > 2.6

Breakup of molecules

Possible Possible

CS optimization Partially possible Well suited

Energy spread of ions

negligible Up to 0.5% for high current devices

Ion beam acceptance

Large Small

Complementary devices !!Complementary devices !!

EURISOL: Comparison EBIS v. ECRIS

(O. Kester, GSI)

© CERN - European Organization for Nuclear Research / Pekka Suominen

ARC-ECRIS (1/2)ARC-ECRIS (1/2)

Conventional ECRIS is based

on solenoids + hexapole

magnet configuration

ARC-ECRIS is based on “yin-

yang” or “baseball” type

magnets as used in former

fusion experiments in 60’s 6.4 GHz prototype already

constructed and tested at

JYFL Next step is to make

a full scale device operating

at 14 GHz or over.

a) b)

First prototype

(constructed & tested)

Second prototype

(under design)

(P20: Pekka Suominen)

© CERN - European Organization for Nuclear Research / Pekka Suominen

ARC-ECRIS (2/2)ARC-ECRIS (2/2)

© LLNL

Baseball experiment

• Copper coil version– Simple, robust and radiation hard– No permanent magnets Possibly to

use hot plasma chamber (200 C)• Ultra high vacuum, shorter sticking time

– Easy access to the plasma chamber• Easy instrumentation• Chamber easy and cost-effective to change

– 14 GHz (0.1 MW)– 28 GHz (1 MW)– [60 GHz (>>MW)]

• Superconducting version– Highly charged heavy ions– NbTi up to 60 GHz– Nb3Sn up to 100 GHz– Radiation hard SC-version for RIB is

under study

• Not only for RIB, but interesting option also for stable highly-charged heavy-ion beam production

(P20: Pekka Suominen)


Objectives:- Design a high-intensity pulsed 60 GHz ECR ion source for rapid ionization of light noble gas radioactive ions, especially He and Ne- Realize of a conceptual prototype suitable for the beta-beam project.

Realized:

18 - 28 GHz cw and preglow studies performed with PHOENIX V2 fed with 3He and 22Ne, extensive studies performed with Ar to understand the nature of Preglow

D8, Bunched efficiency preliminary study - 60 GHz Intermediate report on bunched efficiency

Scientific International Collaboration Program with IAP Nizhny Novgorod (Russia), experiments at 37.5 and 74 GHz in cusp configuration, theoretical interpretation of the preglow performed

0 2 4 6 8 10 12Time (ms)

Inte

nsi

ty ( A

) Ar3+

Ar4+

Ar6+

Ar7+

Ar8+

Ar9+

Ar2+ Microwave pulse

0

800

Preglow

Afterglow

18 GHz, 950 W

0 2 4 6 8 10 12Time (ms)

Inte

nsi

ty ( A

) Ar3+

Ar4+

Ar6+

Ar7+

Ar8+

Ar9+

Ar2+Microwave pulse

300

0

28 GHz, 3600 W

Steady states reached at 3 ms for all charges !!

HeAr

-beam ion source (1/3) (T. Lamy)


(Grenoble High Magnetic Field Laboratory + LPSC) MeetingThe Ion Source Service activities and objectives have been presented, the 60 GHz program discussed.A collaboration contract agreement will be signed by the end of September.Agreement concerning the construction of an ion source with a magnetic field established by Bitter coils and/or Polyhelix technologiesGHMFL will bring its expertise with such technologies, LPSC will perform the design, construction and integration of the prototypeLouis Latrasse (EURISOL Engineer) is in charge of this activity (Poster P10)A first prototype will be chosen, designed and built either in an axisymetric MHD stable Cusp configuration either in a Minimum B one:

7T

1.5T

4T

ECR

7T

1.5T

4T

ECR

1.5TPlasma

Magnetic profile

6T 3T

Bitter StackAxial and radialmagnetic field

60 GHz prototype

GHMFL poly helix technology

-beam ion source (2/3)


Test bench for 60 GHz prototype Magnetic field measurements performed at GHMFL with LPSC

High acceptance magnetic spectrometerUnder design with GANIL, funded by IN2P3, order placed by the end of 2007

First 60 GHz prototype (magnetic field, plasma chamber and extraction) : Fall 2008

Gyrotron 60 GHz CPER (Government, Region, Institutions project contract) accepted and signedTechnological Platform Plasmas-SIRCE (Electron Cyclotron Resonance Ion Sources) created300 k€ allocated by IN2P3 in 2008 1 Gyrotron delivered end 2008

-beam ion source (3/3)


EURISOL LAY-OUT


Requirements from NA Community

“C. Angulo, subtask “Astrophysics”, EURISOL Week, CERN, 27 – 30/11/2006”

How much beam time can be devoted to nuclear astrophysics experiments

(very time-consuming)?

”Nigel Orr, previous Town Meeting”:

Essential aspect of facility, but FP5 proposal of sharingEssential aspect of facility, but FP5 proposal of sharingusing unused charge state(s) from stripping of using unused charge state(s) from stripping of very little utilityvery little utility..

Many VLE and LE/Coulomb barrier expts (0-5MeV/u) require Many VLE and LE/Coulomb barrier expts (0-5MeV/u) require very extendedvery extended periods periods of beamtime with of beamtime with samesame beam (astro’, heavy elements, etc). beam (astro’, heavy elements, etc).

Dedicated VLE, LE and HE reaccelerator(s) [~0-1, ~1-5 and ~5-150 MeV/u] coupled Dedicated VLE, LE and HE reaccelerator(s) [~0-1, ~1-5 and ~5-150 MeV/u] coupled to separate target-ion source beam preparation systems * … to separate target-ion source beam preparation systems * …

ie. Beam sharing of driver accelerator beamie. Beam sharing of driver accelerator beam


Schematic lay-out

Target-ion sources

Pre-separators,beam gates

Ion cooling and bunching

High-resolution separators

Charge breeding:EBIS and ECR

q/m selection

Electrostaticdeflection

Post-acceleration andExperimental areas

Beam preparation lay-out:

Two complete beam preparation chains

Two parallel mass-purified beams for on-line experiments

Two charge breeders: EBIS (fast, low capacity, low

background, narrower charge state distribution, provides intensity also for light elements)

ECR (slow, high capacity, high background, access to intense beams including stable ones)

Modular (easy to expand) Robust (electrostatic deflectors

without moving parts)


Target stations and front-ends

• New front-end design of 100 kW-target stations (C1: Thierry Stora)

• Vertical extraction• Integration of the pre-separation

Body tubeMAFF-approach to EURISOL (C2: Yacine Kadi and P32: Cyril Kharoua)

Fission target design has been revisedVertical extractionMerging beams to be solved

1 GeV Multiple ExtractionExtremely flexible solution

Alberto Facco, A1Rita Paparella, A3


Velocity matching (1/2)

Post-accelerator assumes (Task 6) :– Monochromatic beam– Multiply charged (A/q=4-8)– CW beam– Rather low injection energy

Low-energy beam transfer (Task 9): – Fixed energy– Pulsed beam– Preferably few tens of keV

Variable 1+ energy of the low-energy transfer: - unpractical (low-E transport relies on fixed optical settings & parallel beams affected by the tuning)

Bunching cavities just before the RFQ of the LINAC: - typical transmission losses 30 % radioprotection issue

Pulsed charge breeder: - non-CW operation - high peak intensities in the LINAC (for intense beams) - saturation of EBIS


Velocity matching (2/2)

RFQ-cooler just before the charge breeder:- cooled and bunched beam for charge breeder- high transmission- low-energy beam transport (60 kV) decoupled from injection to the post- accelerator (5 keV/u, i.e. 20-40 kV if A/q between 4 and 8) - With fast pulsing ”semi-CW” operation and high capacity- Could be combined with a large drift tube section allowing fine-tuning of the V(n+) beam


Summary

• Steady progress in sub-tasks:

• Multiple multipolar scheme exists for high-resolution mass selection.

• Based on the existing ion cooling devices and experience gathered with those, a high-intensity cooler has been proposed. Such a device is under construction in Orsay and wil be moved to LPC-Caen for further development and testing

• ISCOOL at CERN an important testbench (space-charge).

• Charge breeding: ECR and EBIS approaches have been developed and compared within EURISOL and EURONS. (Efficiency, capacity, purity, …)

• A new concept – ARC-ECR - has been proposed (JYFL)

• An innovative source for beta beam has been proposed and is under construction in LPSC-Grenoble.

• To fullfill our task, work has to be done:– Solution for the velocity matching (Task 6 and 9)– Lay-out (Task 6,9,10 and 5)– The parameter database, especially efficiencies for safety task for the radiation

shielding estimation

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