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Anastasios LagoyannisTandem Accelerator Laboratory
Institute of Nuclear and Particle PhysicsN.C.S.R. “Demokritos”
Current and Future projects at the
TANDEM accelerator
Tandem Layoutμ
-PIX
E
RBS , NRA, ERDA …Charged-particle induced X rays
Auger Spectrom.
Ato
mic
ph
ys
ics
multipurpose
scattering chamber4 HPGe detect. array
γ - spectrometry charged-part. irradiations
d-filled gas-cell
TritiatedTi-target(rotating)
ne
utr
on
irr
adia
tio
ns
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
γ - calorimetry
Nuclear Astrophysics
p-processNetwork of more than 20000 reactions
(,n), (,p), (,), n-, p-, -captures,
-decays, e-captures
a huge number of cross sections
have to be known
n captures
p captures
α capturesM. A
rno
uld
an
d S
. Go
riel
y P
hys
. Rep
. 38
4, 1
(2
00
3)
HAUSER-FESHBACH THEORY
r := <>max. / <>min.
for 14 different sets of nuclear ingredients
(OMP, NLD, …) in HF calculations.
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Experimental Methods
A. LagoyannisInstitute of Nuclear and Particle PhysicsNCSR “Demokritos”
HPGe (ε =100%)
15o
BGO Mask
Angular Distribution
discreteexcited
states
ground state
unresolvedexcited states
Compound Nucleus
Target Nucleus
+ p
roje
cti
le
Q-value
+ E
pro
jentry state
primaries
γ0
γ1
γ2
γ3
...
W()=A0(1+a2P2(cos)+ a4P4(cos))
j
j
pA
ANN
A,0
Angular distribution for γ0,γ1,…
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
The 4π γ-summing method
0 2000 4000 6000 8000 10000 12000
103
104
105
106
Co
un
ts /
mC
E (keV)
α + 92Μο
beam-induced bgd
sum
pea
k
Solutions (up to now):
• Theoretical calculations
• Simulation
No “real” experimental solution
=(Y/)*(1/)*(A/NA)
BUT
=ƒ(E,M)
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Efficiency Calculation
pos. apos. b pos. c
in/out ratios:
M=1 R = 2
M=2 R = 2 × 2 = 4
M=3 R = 2 × 2 × 2 = 8
M=4 R = 2 × 2 × 2 × 2 = 16
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
BGO Ball
80 BGO crystals
• Thickness = 6.5 cm
• ΩBGO
~80%
• ε ~ 95% @ 1000 keV
• εtot
~ 70% @ 1000 keV
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Ion Beam Analysis Techniques
Ion Beam Analysis (IBA) is based on the
interaction of a high-energy charged
particle with the electrons and the nuclei of
the material atoms.
This interaction can lead to the emission of
particles or radiation the energy of which
is characteristic of the elements that
constitute the sample material.
Method Interaction Ideal for
Backscattering Spectrometry
(RBS/EBS)Elastic scattering at backward angles
Depth profiling of heavy elements in
light or medium-Z matrices
Elastic Recoil Detection
Analysis (ERDA)Elastic recoil at forward angles Depth profiling of light elements
Nuclear Reaction Analysis
(NRA)
Nuclear reaction between beam and target
nuclei, producing a light charged particle
Depth profiling of light elements in
high- or medium-Z matrices
Particle-Induced Gamma–ray
Emission (PIGE)
Prompt γ-ray emission during ion beam
irradiation
Bulk analysis of light elements from
hydrogen to silicon
Particle-Induced X-ray
Emission (PIXE)
Characteristic X-ray emission following
ionization by the primary beamBulk analysis of elements with Z>11
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Differential Cross Section Measurement
Differential cross sections for EBS - RBS
natMg(d,d0)natMg
Ed,lab = 1660 – 1990 keV
Angles = 90o to 170o
N. Patronis et al, Nucl. Instr. and Meth. B 337 (2014), 97.
Motor driven goniometer
Great angular accuracy (0.01 deg.)
Up to 4 targets
Water cooling available
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
10B(p,p’γ)10B
Differential Cross Section Measurement
• Electronically controlled turntable
• Initial angles: 0o – 55o – 90o ‐ 165o
• 4 HPGe detectors (1 – 80%, 3 – 100%)
placed between 25 and 30 cm from target
• Air cooled target
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Benchmarking
• Acquisition of thick target spectra to different beam energies and angles
• Different thick target matrices (channeling - stopping power effects)
• Simulation of the spectra with the existing cross sections
• Theoretical calculations R - matrix (if possible)
V. Paneta et al, Nucl. Instr. and Meth. B 318 (2014), 1
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
NRA Example
Plasma Facing Components on JET/Tokamak
Study of the erosion, deposition, materials
migration and fuel retention in fusion plasma
devices.
Understanding the mechanisms
predict the lifetime of wall components & assess
the amount of fuel retained in the machine
Depth profiling of D, Be, C, N, O
NRA with a deuteron at Ed= 1.7 MeV.
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Elastic Recoil Detection Analysis
Heavy ions are used as the ion beam
Suitable for the detection of
light elements (Z<17) on heavy substrates
Used for H, D, He depth profiling
Detection of the light nuclei at
forward angles
In simple ERDA experiments necessary to
use filters in front of the detector in order to
stop the heavy beam ions
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Time Of Flight ERDA
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Micro beam
Ancient spoon found in Mykines, Greece
Beam spot is reduced to μm
micro-structural elemental analysis
Elemental mapping capability
Small samples analysis
Low beam currents
time consuming
Au Ca
O Si
Zn Cu
Ag Mo
External Beam Setup
A. LagoyannisI.N.P.P. MeetingWednesday 15/11/17
Recommended