Division Accélérateurs

Radioactive Beam Production by

PhotofissionAlex C. Mueller, Accelerator Division, IPN ORSAY, CNRS/IN2P3

(Seminar at the CERN PS-Division, June 13, 2001)

Alex C. Mueller, CERN PS-Div., June 2001, T 1

• Introduction

• Scientific Motivation

• Making Radioactive Beams

• Considerations on the Intensities

• X-sections for Fission Fragments

• The PARRNe R&D Programme

• PARRNe-1 at the LEP-injector

• Experimental Results

• Concluding Outlook

Nuclei far from stabilitykey objects in for the nucleosynthesis in the

universe

Alex C. Mueller, CERN PS-Div., June 2001, T 2

• Supernova explosion neutron-rich nuclei

• Gravitational collapse of a massive star to a neutron star

neutron-rich nuclei "neutron-matter" simulating systems

• Nova explosion proton-rich nuclei

Nuclear Forces and the Nuclear Many-Body Problem

effectiveeffectiveNN forceNN force

quarks & gluonsquarks & gluons

free NNfree NNforceforce

nucleonnucleon

light nucleilight nuclei

medium-massmedium-massand heavy nucleiand heavy nuclei

Derivation of the effective NN force

in nuclear medium Derivation of the bare NN force from QCD

The view of the Polish/US theoreticalnuclear physicist Witold Nazarewicz:

Alex C. Mueller, CERN PS-Div., June 2001, T 3

Chemistry and Physics of the

heaviest elements

Alex C. Mueller, CERN PS-Div., June 2001, T 4

Fusion Reactions with neutron-rich beams,like 132Sn, might give acces to this region

The colors in the figure below correspondto the binding energy ("shell stabilization),hence to the life time.In the dark blue region the lifetime mayreach years or more.

Radioactive Beams also have a numberof Applications

(examples from CERN-ISOLDE Webpage)

Alex C. Mueller, CERN PS-Div., June 2001, T 5

The Two Production Methods for Radioactive Beams

and their combination, "RIA" proposed in the US

Alex C. Mueller, CERN PS-Div., June 2001, T 6

"In-Flight"

RIA,combiningISOL & In-Flight

ISOL = Isotopic Separation On-Line

An ISOL facility including post-

acceleration: SPIRAL phase I

Alex C. Mueller, CERN PS-Div., June 2001, T 7

- Driver (GANIL cyclotrons)- Target-ion source system- Post-accelerator cyclotron CIME- I up to 109 pps- Mass range: up to A=100Into operation by summer 2001

Secondary radioactive beam

intensities

Alex C. Mueller, CERN PS-Div., June 2001, T 8

An example for nuclear reaction

cross sections (fission)

Alex C. Mueller, CERN PS-Div., June 2001, T 9

(Calculations: Ridikas, ENAM 98)

Optimising the Production

Alex C. Mueller, CERN PS-Div., June 2001, T 10

•In-Flight : get large high-power accelerator R&D

get N large high-energy > 1 1 GeVGeV

get large high-energy > 1 1

GeVGeV

•ISOL : get large high-power accelerator R&D

get large R&D on target and

ion-sources, like PARRNe

Limits of the ISOL technique:

power deposit in the target

Alex C. Mueller, CERN PS-Div., June 2001, T 11

distance de parcours dans la cible

dE/d

x

Pic de Bragg

Inconvénient des faisceaux intenses de particules chargés :

ralentissement des particules dépôt d’énergie localisée en fin de parcours (pic de Bragg)

Utilisation des neutrons :

toute l’énergie incidente est dissipée dans la réaction nucléaire

Neutrons thermiques :

réacteur nucléaire

235U

Neutrons rapides :

238U utilisable

ISOL at the highest power

levels

Alex C. Mueller, CERN PS-Div., June 2001, T 12

• One stage : direct use of charged particles,

minimize dE/dx (low Z, high E at 1 GeV max. 100 - 200 kW • Two stage : use neutral particles in second stage, i.e. neutrons & photons for neutrons 5 MW of proton beam (like spallation source)

RIA (fragmentation + gas collec-

tion scheme) is also in this class

Original Motivation for Spiral-II

Alex C. Mueller, CERN PS-Div., June 2001, T 13

A new driver: d (60 - 200 MeV) with high intensity I = 50 - 200 mA

Dedicated cyclotron or GANIL SSC fission induced by neutrons Fission products accelerated in CIME cyclotron

90Kr, 132Sn I > 101O pps

High Intensity Linacs for future

ISOL Facilities

Alex C. Mueller, CERN PS-Div., June 2001, T 14

The PROTON The PROTON linaclinac driver driver

?? ?? ?? ??

5 MeV100 keV 10 MeV

RFQRFQ

So

urc

eS

ou

rce

DTLDTL

500 MeV100 MeV 200 MeV

= 0.65 = 0.5 = 0.85

1GeV*

DTL, SC DTL, SC cavitiescavities…?…?

LOW ENERGYLOW ENERGYsectionsection

INTERMEDIATEINTERMEDIATEsectionsection

HIGH ENERGYHIGH ENERGYsectionsection

InjectorInjector SCRF SCRF cavitiescavities

* 2GeV possible

• "Generic" lay-out for the EURISOL project

• note similarity with other projected linacs

factory (CERN SPL) nuclear waste trans- mutation Neutron Spallation Source (SNS, ESS) Material Irradiation

Target R&D needed,justification of the PARRNEprogramme for fission fragment production

PARRNe-1(European RTD: IPN-Jyväskylä-Louvain-GANIL-KVI)

Alex C. Mueller, CERN PS-Div., June 2001, T 15

deuteron

converter heatedtarget

secondarypump

spectrometry

cryofinger(12 K)

turbomolecularpump (50l/s)

noblegas

nucleus

neutronflux

PARRNe-2 at the Orsay Tandem

Alex C. Mueller, CERN PS-Div., June 2001, T 16

Targets

Sources

UCx

Molten U

Nier Bernas

Isolde MK5

+

Elements already produced with PARRNe-2 (>100

isotopes)

Alex C. Mueller, CERN PS-Div., June 2001, T 17

PARRNe 23.5 105 132Sn extracted

SPIRAL 21.1 109 132Sn

Before acceleration

Present Rates with PARRNe-2

(here upper fission hump)

Alex C. Mueller, CERN PS-Div., June 2001, T 18

2/2

Production / s/ µA

Stable

102 – 103

103 – 5 103

5 103 – 104

104 – 5 104

5 104 – 105

105 – 5 105

5 105 – 106

106 – 5 106

5 106 – 5 1017

Production à PARRNe

Source d’ions MK5

1µA deuton

26 MeV

Photo-fission:the idea and involved processes

Alex C. Mueller, CERN PS-Div., June 2001, T 19

• Photo-electric effect• Diffusion (Compton, Raleigh)• Pair Production (e+e-) • Nuclear Reactions

•(, f) GDR (Giant Dipolar Resonance) •(, n) •(, 2n)

e-

• Bremsstrahlung• Ionisation • excitation

Cible 238UCxCible 238UCxConvertisseurConvertisseur

Production of photons by Bremsstrahlung and X-section

for photofission

Alex C. Mueller, CERN PS-Div., June 2001, T 20

.

Data compiled by Yu.Ts. OganessianJINR-E7-2000-83 Fission probability:

0.6%/e @ 50 MeV!

e-

Ecm

2

0 2-3o

Distribution of the produced nuclei

in Photofission

Alex C. Mueller, CERN PS-Div., June 2001, T 21

Photofission

e-

+

U

U*

n

FP

FP

Bremsstrahlung

ExcitedNucleus at (GDR)

Fission

The set-up of the CERN experiment

Alex C. Mueller, CERN PS-Div., June 2001, T 22

Collaboration

IPN Orsay

ISOLDE CERN

GANIL

CEA Saclay

Cryogenic finger

UCxTarget

Transport tube

e¯ beam

Photo fission experiment at LIL (CERN)

e-

to cryofinger

W converter

Photon flux

Radioactive noble gases

Location of the converter and the target

Alex C. Mueller, CERN PS-Div., June 2001, T 28

The experiment:cryogenic collection and data

acquisition

Alex C. Mueller, CERN PS-Div., June 2001, T 24

Collection on the cryogenic finger and measurements

3 measurementsConverter @ 8 cmConverter @ 4 cmWithout converter

To the acquisition

PCSUN

COMET

A typical -spectrum from the radioactive decay from the collected

fission fragments

Alex C. Mueller, CERN PS-Div., June 2001, T 25

Results @ CERNand comparison with fast-neutron

data

Alex C. Mueller, CERN PS-Div., June 2001, T 26

Productions de Kr

1,E+04

1,E+05

1,E+06

1,E+07

1,E+08

88 89 90 91 92 93

Nb de masse A

Nb

de

no

ya

ux

/mA

conv 8cm

conv 4cm

sans conv

KVI 80

Without Conv.

KVI 80 MeV D

4 cm Conv.

8 cm Converter

Inspection of the target after irradiation

Alex C. Mueller, CERN PS-Div., June 2001, T 27

SPIRAL-IIand other projects

Alex C. Mueller, CERN PS-Div., June 2001, T 28

Dubna: DRIBS project, under constructionChalk River: theoretical Study by W.T. DiamondSPIRAL-II: here with photofission

Perspectives

Alex C. Mueller, CERN PS-Div., June 2001, T 29

injectorinjector

collimatorcollimator

=1 section=1 section

beambeam dumpdump

analysisanalysis

targettarget

beambeamdumpdump

transport transport lineline

deviationdeviation

100keV100keV 5MeV5MeV 50MeV50MeV

4 SCRF 4 SCRF cavitiescavitiesee--gungun capture SCcapture SC cavitycavity

injectorinjector

collimatorcollimator

=1 section=1 section

beambeam dumpdump

analysisanalysis

targettarget

beambeamdumpdump

transport transport lineline

deviationdeviation

100keV100keV 5MeV5MeV 50MeV50MeV

4 SCRF 4 SCRF cavitiescavitiesee--gungun capture SCcapture SC cavitycavity

Figure 3

20 m long

• Complete R&D Programme with the LPI front-end and PARRNe-2

• SPIRAL-2 (Scientific&Technical Proposal presently under evaluation

• The "ultimate" EURISOL electron driver

Spallation vs. Photofission from

Alex C. Mueller, CERN PS-Div., June 2001, T 30

Comparison Spallation / Photofission

y = 0.1827x 0.1626

y = 0.0759x 0.1446

0

1

10

100

1 000

1.E+12 1.E+13 1.E+14 1.E+15 1.E+16 1.E+17 1.E+18 1.E+19

Neutron Flux (n/s)

Inv

es

tme

nt

Co

st

(ME

uro

)

SPALLATIONPHOTOFISSION

Conclusion of the first part…

Alex C. Mueller, CERN PS-Div., June 2001, T 31