Transcript Slide 1

Light Radio-isotopes
Nuclear Astrophysics, Neutrino Physics
and
Fundamental Interactions
O. Aviv1, D. Berkovits2, M. Hass1, O. Heber1, T. Hirsh1,2,
V. Kumar2, M. Lewitowicz3, F. de-Oliveira3, G. Ron4,
S. Vaintraub1,2
1. The Weizmann Institute of Science, Rehovot, ISRAEL
2. Soreq Nuclear Research Center, Yavne, ISRAEL
3. GANIL, Caen, FRANCE
4. LBL, Berkeley, USA
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Or
A glance at current Experimental Nuclear Physics
at the Weizmann Institute
 Nuclear Structure Far-From-Stability – Radioactive Beams
 Nuclear Astrophysics
 Fundamental Interactions
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‫‪ 07‬יולי ‪15‬‬
Secondary neutrons + fission
BUT
Also light RIB’s
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14 UD Pelletron Accelerator at the WI
“20th Century”
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ECR Ion Source, RFQ and 1st cryo-module in situ
“21st Century”
The SARAF accelerator
at Soreq, Israel.
Summer 2009
Final Commissioning
of Phase –I
Nov. 2009 –
1 mA p @ 3.5 MeV
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 Two-stage
production scheme
Also with a 14 MeV d+t
“neutron generator” at
the WI
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6He
and 8Li beams in WIS
~1010 n/sec
14.1 MeV
WIS d-t NG
Heated Porous
BeO or B4C target
~6∙107 6He/s
~2∙107
8Li/s
Ionization
Extraction
by diffusion
High efficiency
8
Efficiency ?
production (n,a) cross section
120
700
9
n in Be target
Be(n,a) He
100
Bass 1961
Savilev 1958
Stelson 1957
Stelson 1957
MCNP
80
60
Cross section (mb)
Cross section (mb)
3.5E+12
6
40
600
3.0E+12
500
2.5E+12
9
400
Be(n,2n)
2.0E+12
300
1.5E+12
200
1.0E+12
9
6
Be(n,a) He
100
n flux per 2 mA d (s-1)
6He
5.0E+11
20
0
0.0E+00
0
0
5
10
15
20
n energy (MeV)
0
2
4
6
8
10
neutron energy (MeV)
Production yield of the order of 5∙1012 6He per 1 mA d@40 MeV
Remember also 11B(n,a)8Li
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6He
vs. 8Li Production using
SARAF/SPIRAL2 40 MeV d on
Lithium neutrons
SARAF/SPIRAL2 d-Li neutron
flux is more suitable for 6He
production than 8Li
9Be(n,α)6He
 βt0.5= 807 ms
6He
11B(n,α)8Li
 βt0.5= 838 ms
8Li
10
Extraction of
RIB
BeO
BN
ISOLDE Exp. T.
Stora at al.
17.4.2009
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Preliminary results of ISOLDE BeO run – April 2009
See talk by Thierry Stora – this WORKSHOP
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Fusion Reactions in the Sun:
The main p-p chain
WI
15 ‫ יולי‬07
‫ מפגשים‬- ‫מיכאל הס‬
2009 ‫בחזית המדע‬
Theory vs. Experiment for the 3 solar-neutrino
experiments
SNU
SNU
SNU
 n + 37Cl
 n + 71Ga
37Ar + e-
71Ge + e-
E(n) > 0.81
MeV
E(n) > 0.23
MeV
15 ‫ יולי‬07
‫ מפגשים‬- ‫מיכאל הס‬
2009 ‫בחזית המדע‬
The SNO (Sudbury Neutrino Observatory) Experiment
A D2O Detector
 Neutral currents vs Charge Currents
15 ‫ יולי‬07
‫ מפגשים‬- ‫מיכאל הס‬
2009 ‫בחזית המדע‬
The “Standard Model” of Particle Physics
15 ‫ יולי‬07
‫ מפגשים‬- ‫מיכאל הס‬
2009 ‫בחזית המדע‬
The b-beam Concept
Production of an intense collimated neutrino (anti
neutrino) beam directed at neutrino detectors via
b decay of accelerated radioactive ions
6He
18Ne
8Li
SPL
ISOL target
& Ion source
Cyclotrons
Storage
ring and
fast cycling
synchrotron
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6Li
+ e- +n
18F + e+ + n
8Be + e- + v
Decay
SPS
To the French Alps
Ring
PS
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Mass accretion from a companion into a
neutron star (black hole).
 Role of 14O, 15O and 18Ne in the physics
of x-ray bursts
4He(15O,g)19NE
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M. Wiescher et al. Erice Conference, 2007
J.L. Fisker et al., arXiv:astro-ph/070241
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Type II Supernovae
8Li(a,n)11B
‘2000
g.s.
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Example: 6He beta decay
See, e.g, Flechard et al, PRL (2008)
6Li
e- Electron
 daughter nucleus
Pure Gamow-Teller
p

dW  a e cosq 
 Ee


1 p
dWSM ( 6He)    e cosq 
3  Ee

q
6
He6Li + e +e
ne Electron
 anti-neutrino
New physics beyond the Standard Model’s
 V-A structure

2
0
β-Decay Physics

Transition rate W (inverse lifetime)
 In case of nonoriented nuclei
 


pe  pn
m
dW   1 + a
+ b + ...
Ee En
Ee


Beta-neutrino correlation coefficient

In case of oriented nuclei (J - nuclear polarization)
 
 


 ( pe  pn )


 ( J  pe )
pe
dW   1 + A  J + DJ 
+ R e 
+ ...
Ee
Ee En
Ee




J. D. Jackson, S. B. Treiman and H. W. Wyld, Nucl. Phys. 4,
206 (1957)
2
1
Why RNB’s in Traps?




No possibility for detection of neutrinos
Small effects measurements - low energy of ions, multiple scattering,
angle resolution
Atoms/Ions - “point source” in a trap
 Increase of accuracy in measurements:
 Angular correlations

Energy
2
2
Current Status on 6He
 ~2 % limit on any possible deviation – hence improve limit
 Statistics + systematic limitations
 Flechard et al: Paul trap, but “….MOT (Magneto Optical Trap)”
 But He is noble gas – metastable state for MOT. LOW EFFICIENCY.
 Statistics
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Optical resonator
Particle resonator
Ek, q
V
V
V>Ek/q
M
Trapping of fast ion beams using electrostatic field
L
Field free region
Entrance mirror
Exit mirror
L=407 mm
Trapping ion beams at keV energies
Neutrals
Field free region
Ek
V1
V2
V3
V4
Vz
Vz
• No magnetic fields
• No RF fields
Why is this trap different
from the other traps?
• No mass limit
• Large field free region
• Simple to operate
• Directionality
• External ion source
• Easy beam detection
Detector (MCP)
V1
V2
V3
V4
MPI – HD Participation
Fig. 2 A schematic view of the EST for bdecay studies. The radioactive ion, like 6He,
moves with Ek-4.2 keV between the
reflecting electrodes. The b electrons are
detected in position sensitive counters while
the recoiling ions, due to kinematic focusing,
are detected with very high efficiency in
either one (determined by the instantaneous
direction) of the annular MCP counters.
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(Very) preliminary simulations
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“In- House” Research!
R&D steps at the WI
 6He (+ ions) and 8Li (neutrals) production and extractions
 EIBT parameters (bunching (pre-trapping),bunch size, timing
(with 4He) --- Re-use hardware from the 14 UD Pelletron
 RNB in Trap and detection system
 First measurements
 SARAF…
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http://www.weizmann.ac.il/conferences/NPA5.
Tentative results
O16(a,2n)18Ne
3.0E+10
F19(p,2n)18Ne
2.5E+10
Cross Section (mb)
3.5
Alice
Yield [at/s]
3.0
2.0E+10
2.5
1.5E+10
2.0
1.5
1.0E+10
1.0
5.0E+09
Cross Section (mb)
4.0
Yield (atoms/sec) (Intensity 0.1mA)
2.5
9.0E+11
8.0E+11
Alice
Yield [at/s]
2.0
7.0E+11
6.0E+11
1.5
5.0E+11
4.0E+11
1.0
3.0E+11
Yield (atoms/sec) (Intensity 2mA)
4.5
2.0E+11
0.5
0.5
1.0E+11
0.0
0.0E+00
29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81
Alpha Energy (MeV)
0.0
0.0E+00
15
17
19
21
23
25
27
29
31
33
35
37
39
41
Proton Energy (MeV)
Lower yield, but, better extraction..
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E(8Li [MeV])
8Li
energies of interest
6
3
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R&D Steps
Via neutron converter – 6He, 8Li, ..
 Simulations – Geant4, MCNP – PRODUCTION rate of ~1013/mA!!!
 Converter design
Target design – Diffusion & Extraction (BeO fibers,
Boron Nitrite fibers)
Direct production – 14,15O, 18Ne,..
 Design of targets (heat) for direct production (O and Ne);
materials (gas?), …
 Extraction. Nitrogen is “bad”. Perhaps C02? M. Loiselet, LLN
12C(3He,n)14O
and 12C(4He,n)15O
Experiment: Beam, Team, Detectors (RMS-like, Si ball, EXOGAM..)…
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Towards a full proposal – objectives and milestones.
 2007-2009 FP7 (Task 7.1) . Towards establishing a true collaboration.
Initial target design. R&D studies of both n-converter and direct production.
Test runs:
Soreq neutron generator
Soreq Phase I
GANIL (neutrons from C+C)
ISOLDE (neutrons from 1 GeV spallation)
 2009-2011 Target (s) manufacturing. Parameters for experimental setup, synergy with
detector (particle, gamma, separator) projects
 2012-……. SPIRAL-II
 2012-……. SARAF??...
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B4 C
We initiated the heating for Boron Carbide with temperature ~2000 C.
During the first few stages (T=200-5000 C), the heating was put off in between,
as the vacuum deteriorated beyond the limits. But then after it reached 500o C,
the process was continued in steps, so that vacuum may not deteriorate beyond 10-5.
-5
B
2.0x10
-5
1.8x10
-5
1.6x10
-5
1100
1.4x10
1000
1.2x10
900
1.0x10
-5
Vacuum
Temp. (C)
1200
-5
-6
8.0x10
800
-6
6.0x10
700
-6
4.0x10
-6
600
2.0x10
0.0
500
400
0
1000
2000
3000
Time (min)
4000
5000
6000
0
1000
2000
tim 30004000
e (m
in.)
5000
6000
GANIL 2010 – test of diffusion-effusion of porous B4C (?)
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1200
1100
1000
900
)
800
ius
700
els
c
(
600
p.
500
tem
400
36
Partial sample of representative papers
The Astrophysical Journal, 650 (2006) 332
J.L. Fisker et al.
The Importance of 15O(a,g) 19Ne to X-Ray Bursts and Superbursts
Arxive-ph/0702412 Feb. 2007
J.L. Fisker et al.
Experimental measurements of the
15O(a,g
)19Ne reaction rate vs.
observations of type I X-ray bursts
Nuclear Physics A 718, (2003) 605
B. Davids et al.
Alpha-decay branching ratios of near-threshold states in
astrophysical rate of
19Ne
and the
15O(α,γ)19Ne
PRC 67 065809 (2003)
K. E. Rehm et al.
Branching ration Ga/Gg of the 4.033 MeV 3/2+ state in 19Ne
Nuclear Physics A 688 (2001)465c.
S. Cherubini et al.
The
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15O(a,g)19Ne
reaction using a
18Ne
radioactive beam
37
SUMMARY
 Scientific Case
 Calculations and simulations exist – but much more R&D needed
Presented at several recent scientific conferences .
Funds: EC (infrastructure), Local
 “Road Map” towards a full experiment – test experiments!
 OPEN COLLABORATION – participation welcome!!
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β-Decay Physics
For pure Fermi or pure Gamow-Teller (GT) transitions the
correlations coefficients become independent of the nuclear
matrix elements

The correlations coefficients
depends on 'scalar, vector, axialˆ
ˆ
Hb 
Oi n[ecoefficients
Oi (Ci + C
g 5 )e ]Hamiltonian
+ h.c.
vector andptensor
ini β-decay


i  S , P,V , A,T
For example, 6He β-decay (pure GT) beta-neutrino correlation
coefficient can be measured in order to check the presence of
tensor interactions
 
 2 pe 2pn ' 2m ' 2 

a  CT1 +a C A + C
 +C...A
T
dW
+
b
 
 
E
E
E
e n
e



3
9
X-Ray Bursts and the “rp” process
These movies simulate an x-ray burst and the rapid-proton capture (“rp”)
process.
The calculation begins at T9=T/10^9 K=40 with only neutrons and
protons. As time progresses and the temperature drops below T9=10,
nucleons assemble into 4He nuclei then into heavier mass
nuclides. Once T9 falls below about 4, the QSE among the heavy nuclei
begins to break down. Charged-particle reactions freeze out, and flow to
higher mass number occurs via nuclear beta decay. This is the classical rprocess phase.

The rp process
and x-ray bursts site of nucleosynthesis
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A new class of ion trapping devices: The Electrostatic Linear Ion Beam Trap
Physical Principle:
Photon Optics and Ion Optics
are Equivalent
V1
V2
V1<V2
R
R
Photons can be Trapped in an
Optical Resonator
L
Ek, q
Ions can be Trapped in an
Electrical Resonator?
V
V
V>Ek/q
Typical X-ray bursts:
• 1036-1038 erg/s
• duration 10 s – 100s
• recurrence: hours-days
• regular or irregular
Frequent and very bright
phenomenon !
(stars 1033-1035 erg/s)
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A first experimental approach to the
15O
+ a elastic scattering - Eur. Phys. J. A27, 183 (2006)
F. Vanderbist, P. Leleux, C. Angulo, E. Casarejos, M. Couder, M. Loiselet, G. Ryckewaert,
P. Descouvemont, M. Aliotta, T. Davinson, Z. Liu, and P.J. Woods
Recent experiments have determined Ga (or put limits to Ga) for levels in 19Ne up to 5.092
MeV excitation energy. A conclusion is that a direct measurement of the 15O(a, g)19Ne
reaction in the region of astrophysical interest is currently impossible: 15O beams of intensity
larger than 1011 pps on target would be required indeed to measure the 15O(a, g)19Ne
cross-section in inverse kinematics in the energy region surrounding the first state above
threshold, at 4.033 MeV….
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Examples of Reactions with RNB’s for Astrophysics
• 8B(p,g)9C
• 8B(a,p)11C
• 9C(a,p)12N
• 11C(p,g)12N
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Recent Experiments (in progress)
ISOLDE experiment IS424 (Sept. ’07): (in collaboration with P.J. Woods et al.).
The use of a 17F beam from the upgraded REX-ISOLDE facility to study the
astrophysically important 14O(α,p)17F reaction in time reverse kinematics.
• REX-ISOLDE + MINIBALL
• Only ~ 103 17F/s
On-line data of p-g coincidences –
Indicating the 1st excited state of 17F
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EURISOL INTERNATIONAL ADVISORY PANEL:
“…. no progress has been made with the study of alternative production schemes of 6He and
18Ne using low energy beams and strongly recommends that this study be completed….
The outcome of this study is an essential ingredient for the analysis whether it is technically
feasible to decouple EURISOL and the beta-beams completely
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GANIL experiment – accepted by GANIL PAC : (in collaboration with Marialuisa Aliotta et al.)
Plan to investigate the direct 14O(a,p)17F reaction at four different energies
in the energy region Ecm = 1.0-2.5 MeV
Calculated total S(E) factor.
Constructive (+) and destructive (-)
interference between the Jpp=16.15 MeV state and the direct l=1
partial wave contribution are shown.
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Accelerator artist view
40 MeV x 2 mA p / d RF SC linac
2nd – 6th cryostats
40 SC HWR
176 MHz b0=0.15
176 MHz
3.8 m
1.5 MeV/u
M/q2
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1st cryostat
6 SC HWR
176 MHz
b0=0.09
48
6He
or 8Li production
measurements by betas
3 sec
3 sec
9Be
or 11B
foils
3 sec
β
20 sec
20 sec
d beam
C
Or other pulsed
neutron source
√
Easy experiment
n
β
n
β
β
Extra material for
(n,2n), maybe Pb
√ Calibration of production for
future extraction experiments
x
All cross sections are already known
x
Measuring 6He and 8Li betas is hard
x
Only very thin targets are possible
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11BN
SEM picture
of BN
√ High Melting Point
√ Exists in fibers and nanotubes forms
√ Could be bought in any shape and form.
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9BeO
ZrO2
√
High Melting Point
√
Could be made in fibers form.
√
x
No need of enrichment
Very toxic.
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 Model dependence of the neutrino-deuteron disintegration cross sections at
low energies
7 July 2015
http://il.arxiv.org/abs/nucl-th/0702073v1
52
msm = 3•10-19 [mn/eV], but…..
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3 sec
8Li
measurement
Production Experiment
0.1 sec
3 sec
irradiation
time
54
Schematics and pictures of ISOLDE setup
Together with Tierry Stora and the ISOLDE Ion-Source group
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Neutrino oscillations “101”
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Typical properties of boron carbide.
B4C
Property
Density (g.cm-3)
Melting Point (°C)
Hardness (Knoop 100g) (kg.mm-2)
Fracture Toughness (MPa.m-½)
Young's Modulus (GPa)
Electrical Conductivity (at 25°C) (S)
Thermal Conductivity (at 25°C) (W/m.K)
Thermal Expansion Co-eff. x10-6 (°C)
Thermal neutron capture cross section
(barn)
2.52
2445
2900-3580
2.9 - 3.7
450 - 470
140
30 - 42
5
600
Particle Size 3
Composition of Particles:
Crystal Whiskers 3, 5
Platelet single crystals3, 5
Isometric crystals3, 5
Thickness of Crystal
Whiskers and Platelets5
Surface Area 4
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100% < 10 microns after
one stage grinding
Typical Values as
%
of weight
> 20
> 10
Remainder to 100%
< 2 microns
2 - 9 m2/g
57
…..
Fusion Reactions in the Sun:
The CNO cycle17F
14O
7 July 2015
(a,p)
 Proposed at GANIL
58
Long-learned lesson:
“orders-of-magnitude improvement in sensitivity of measurement –
enhanced understanding and possibilities”.
14N(d,2n)14O
cross section and yield
for a 2 mA deuteron beam
14N(d,n)15O
cross section and yield
for a 2 mA deuterons beam
But, extraction of atomic oxygen…
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