Transcript Non-statistical production of 1s2s2p 4P and 1s2s2p 2P states by e- capture to the 1s2s 3S state Theo J.M.

Non-statistical production of
1s2s2p 4P and 1s2s2p 2P states by
e- capture to the 1s2s 3S state
Theo J.M. Zouros
Dept. of Physics, University of Crete,
Heraklion, Crete, GREECE
Atomic Collisions & Electron Spectrometry Laboratory
&
Institute of Nuclear and Particle Physics, Demokritos, Athens
TIFR Mumbai Mar 9, 2015
Guess who?
ISIAC 2007 – Agios Nikolaos, Crete
Enjoying Greek food + beer
by the sea
Dancing to Greek music
TIFR Mumbai Mar 9, 2015
The Mediterranean
Crete
The Island of Crete
50 km
Heraklion
250 km
Area ~
8200 km2 (3200 mi2)
Two mountains ~ 2450 m
Population ~
600 000 winter
> 1 000 000 summer Heraklion population ~ 220 000
Heraklion
Crete
University of Crete - Heraklion
Physics Dept
UoC campus University
Hospital
Medical
school
Physics &
Biology
From my living room
UoC ~ 5000 students
Physics Dept ~ 600 undergrads
50 grads
30 faculty
Basic ion-atom collision processes
Atomic
Energy
levels
continuum
Ea - Auger energy
e-e interaction M
L
Ex
K
capture
K
ionization
K-M
excitation
Ion-atom collision
e-
e-
vt
Zp
Vp
b
Projectile
Ion
Charge q+
Zt
Target
Atom
M-K
radiative
transition
K
KLM
Auger
transition
Atomic Structure: q, Zp, Zt , Ex, Ea…
Collision Dynamics: b, Vp , vt …
Cross section:  (Vp , q, Z p , b, vt , Zt , Ea , Ex ,...)
HCI: Few-electrons - simpler environment
for testing theories
Projectile spectroscopy: Control # of
electrons on ion by selecting its charge
Special interest: Two-electron processes, ecorrelations and deviations from the IPM
TIFR Mumbai Mar 9, 2015
Interest in Highly Charged Ions (HCI)










Basic understanding of atomic collision processes
(simpler systems, isoelectronic studies)
High-Z HCI used to test QED corrections (spectroscopy)
Astrophysical plasmas (Solar Corona etc.)
Fusion research (ionization, recombination - plasma edge
modeling, plasma-wall interactions, diagnostics - JET, ITER)
Cometary X-ray emission (Charge-exchange of solar wind HCIs
with cometary vapors)
Radiation damage, Therapy of deep-seated localized
tumors (energy loss, HCI bombardment of sensitive areas
(brain, eye), narrow Bragg peak)
HCI nano-structuring of surfaces (nano-hillock formation,
potential sputtering)
Guiding of HCI in insulator nano-capillaries
Accelerator physics (source development, lifetime of particle
beams in storage rings)
Instrumentation R & D (spectrometers, position sensitive
detectors, data acquisition)
TIFR Mumbai Mar 9, 2015
The 5.5 MV Tandem Accelerator @ INPP/NCSRT “Demokritos”
The 5.5 MV VdG Tandem delivered the first beams in 1973.
THE ONLY ACCELERATOR FACILITY EXISTING IN GREECE
Operation
2500 hrs/year,
65% external users
Basic Research (60%)
Nuclear Astrophysics
Neutron Physics
Nuclear Reactions on light systems
Applied Research (40%)
Materials,
Cultural Heritage,
Environmental studies
Since 2014 also Atomic Physics!
Demokritos PHOTOS
5.5 MV Demokritos Tandem HVE Accelerator
Tandem terminal
Post stripper
TIFR Mumbai Mar 9, 2015
PHOTOS
New APAPES beam line for Atomic Physics
00 Auger Projectile Spectroscopy
Where beam line will
Setup May 2014
exit the wall Aug 2012
TIFR Mumbai Mar 9, 2015
Projectile Spectroscopy
Kinematic Broadening


  V0   
E(q )  12 m 2



q
DEq
Dq
 DE 0


V0
0
θ  00
Dq
DEq  E(q  Dq ) - E(q )  sinq Dq
DE 0  Dq 2
0
Dq  10  0.0175 rad
 DE 0  DEq / 50
0
Smallest at θ = 00
F. Fremont et al 1997
HDA
PSD
Zero-degree Auger
Projectile Spectroscopy
Best energy resolution obtained at 00 observation!
TIFR Mumbai Mar 9, 2015
Zero-degree Auger
Projectile Spectroscopy
ZAPS experimental station Mar 5, 2015
TIFR Mumbai Mar 9, 2015
Electron transfer in ion-atom collisions:
F6+ (1s2nl)
He-like ions
ion
F7+ (1s2) ion
e-
Ground state
Target
F6+ (1s22s) ion
15
TIFR Mumbai Mar 9, 2015
Electron transfer in ion-atom collisions:
F6+ (1s2nl)
He-like ions
ion
F7+ (1s2) ion
e-
Ground state
Target
F6+ (1s22s) ion
Electron transfer into metastable He-like ions:
eAnalyzer
F6+ (1s2s 3Snl) ion
F7+ (1s2s 3S) ion
Auger eemission
F7+ (1s2) ion
e-
Ground state
Target
16
TIFR Mumbai Mar 9, 2015
e- Analyzer
1s2s2p 3-electron spectrum resulting
from e- capture to He-like beam
1.1 MeV/u
F6+ (1s2s 3S2p)
ion
Tanis et al
PRL 2004
F 7+ (1s2) 75%
τ1/2 = stable
F 7+ (1s2s 1S) <1%
F 7+ (1s2s 3S) 24%
τ1/2 = 0.198 μs
TIFR Mumbai Mar 9, 2015
τ1/2 = 277 μs
1s2s2p 3-electron spectrum resulting
from e- capture to He-like beam
e- Analyzer
1.1 MeV/u
F6+ (1s2s 3S2p)
ion
2p
2s
1s
Tanis et al
PRL 2004
He-like beam components:
τ1/2 = ∞ - stable
F 7+ (1s2) 75%
F 7+ (1s2s 1S) <1% τ1/2 = 0.198 μs
F 7+ (1s2s 3S) 24%
TIFR Mumbai Mar 9, 2015
τ1/2 = 277 μs
Obtaining pure ground state beam contributions
Mixed state (1s2, 1s2s 3S)
Spectrum
25% metastable
Practically pure ground state
He-like beams
Can be obtained
using a gas stripper
Inside the accelerator terminal
Rather than a
foil POST stripper
Benis et al PRA 2004
Foil
stripping
Calculated (R-matrix)
Gas
Ground state
contribution
stripping
TIFR Mumbai Mar 9, 2015
Obtaining pure ground state beam contributions
Mixed state (1s2, 1s2s 3S)
Spectrum
25% metastable
Foil
stripping
Gas stripping at lower energies
Produces He-like ions
mostly in ground state!
Practically
pure ground state (1s2)
Spectrum
< 3% metastable
Benis et al PRA 2004
Gas
stripping
TIFR Mumbai Mar 9, 2015
Obtaining pure ground state beam contributions
C Foil
Post
stripper
Foil post
stripping
B3+
Gas terminal
stripping
Ar Gas
Post stripper
Benis et al PRA 2002
Zamkov et al PRA 2001
TIFR Mumbai Mar 9, 2015
Spin statistics for 2p capture to pure 1s2s 3S
He-like
Initial States
1s 2s 3 S + 2p
1s 2s 1S
<1 %
1s 2 1S
TIFR Mumbai Mar 9, 2015
Spin statistics for 2p capture to 1s2s 3S
He-like
Initial States
Probability
4
6
(1s 2 s 3S )2 p 4P
2
6
(1s2s 3S )2 p 2P
1s 2s 3 S + 2p
1s 2s 1S
1s2
TIFR Mumbai Mar 9, 2015
Spin statistics for 2p capture to 1s2s 3S
He-like
Initial States
Li-like
Final States
Probability
4
6
(1s2s 3S )2 p 4P
2
6
(1s2s 3S )2 p 2P
1s 2s 3 S + 2p
1s 2s 1S
12 MeV C4+
W=1521eV, F=4 (VL4=-684.45V,VL5=1399.32V)
14
1s2
Normalized electron Yields (x 10-11)
4
P
Ne (20mTorr)
12
R = 4P/(2P+ + 2P-)
10
8
6
2
2
S
4
2
P+
2
P-
D
2
0
1480
1500
1520
Laboratory Energy (eV)
1540
4
1s2s2 p P
Spin statistics for 2p capture to 1s2s 3S
He-like
Initial States
Li-like
Final States
Probability
4
6
(1s2s 3S )2 p 4P
1s 2s 3 S + 2p
1s 2s 1S
(1s2s 3S )2 p 2P
W=1521eV, F=4 (VL4=-684.45V,VL5=1399.32V)
14
Normalized electron Yields (x 10-11)
4
1s2
1s2s2 p P
Spin recoupling
1
1s(2s2 p 3P) 2P
4
2
6
12 MeV C4+
4
P
Ne (20mTorr)
12
R = 4P/(2P+ + 2P-)
10
3
1s(2s2 p 1P) 2P
4
8
6
2
2
S
4
2
P+
2
P-
D
2
0
1480
1500
1520
Laboratory Energy (eV)
Final
breakdown
2:1
1540
4P
: 2 P- : 2 P+
8
1
3


12 12 12
Obtaining pure metastable beam contributions
Strohschein et al PRA 2008
TIFR Mumbai Mar 9, 2015
Obtaining pure metastable beam contributions
Mixed – Norm. Ground state
=
Pure metastable state
In 2008
Tanis and company
Used this technique to
measure both mixed
and ground state
contributions in C 4+
beams
Existence
of 2D line
evidence of
incomplete
subtraction
The spectra were then
normalized and
subtracted leaving the
pure metastable
component only!
Strohschein et al PRA 2008 (WMU - Kalamazoo)
TIFR Mumbai Mar 9, 2015
Obtaining pure metastable beam contributions
Ratio of 4P/2P
Pure metastable state
So why the big
discrepancy!?
Spin statistics
Strohschein et al PRA 2008
TIFR Mumbai Mar 9, 2015
Supported also by observation for F7+ beam
Ratio of 4P/2P
~ 1.8 - 4 for He
~ 0.5 – 5 for H2
7
Lee (1991)
Tanis (2004)
6
4
2
2
Ratio - R = e( P)/[e( P+) + e( P--)]
Data:
5
4
Ratio largest at
lowest collision energy
3
2
1
7+
2
3
F (1s /1s2s S) + He
0
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
6
5
4
2
2
Projectile Energy (MeV/u)
7
Ratio - R = e( P)/[e( P+) + e( P--)]
0.2
Clearly something
Is the matter!?
4
3
2
1.875
1
7+
2
3
F (1s /1s2s S) + H2
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Projectile Energy (MeV/u)
Zouros et al. PRA 2008
TIFR Mumbai Mar 9, 2015
1.6
1.8
2.0
First explanation: Pauli exchange interaction?
WMU
• An electron with antialigned spin
can populate either the 1s, 2s or
2p levels, in the later case giving
rise to the 2P+ state
1s2s 3S
• Cannot form 1s2s2p 4P
TIFR Mumbai Mar 9, 2015
Pauli exchange interaction
• A target electron with spin aligned to
the spin of the 1s projectile:
a) can be captured into the 2p
directly to form the 1s2s2p 4P
Tanis et al
PRL2004
Weird?!
b) CANNOT be captured into the 1s
(or 2s) due to Pauli exclusion.
New idea: So instead it interacts with the 1s
(or 2s) e- via a Pauli Exchange Interaction
with one e- transferred to the 2p forming
additional 4P states
The Pauli Exchange Interaction is reminiscent of the
Transfer-Excitation mechanism, but with two
identical electrons doing the Transfer and the Excitation!
- Rather puzzling and difficult to calculate (not possible to date!)
TIFR Mumbai Mar 9, 2015
Alternative hypothesis: Cascade feeding
nl
Overlooked channel:
Radiative cascade Feeding!
Tanis et al considered
capture only to n=2
Significant capture to higher
n=3-7 indicated by our CDW
calculations
Cascade feeding 1s2s2p 4P analysis
Order
For a state p:
depopulating
populating
transitions
E1Selection Rules:
Quartet  Doublet
NOT allowed!
Quartet  Quartet
allowed!
Strong cascade feeding
of 1s2s2p 4P !
Cool!
TIFR Mumbai Mar 9, 2015
Cascade feeding 1s2s2p 4P analysis
Order
Zouros et al,
Phys. Rev. A Rapid Comm. 2008
TIFR Mumbai Mar 9, 2015
But wait a minute!
Shouldn’t the cascades also feed the 2P states too
Thus also enhancing the denominator
of the 4P/2P ratio?
Indeed! But …
TIFR Mumbai Mar 9, 2015
Cascade feeding 1s2s2p 2P analysis
Order
Same E1 selection rules!
However now
Auger transitions
to ground state
much stronger!
They rapidly deplete
higher lying levels!
Minimal cascade
feeding
of 1s2s2p 2P !
TIFR Mumbai Mar 9, 2015
Cascade feeding 1s2s2p 2P analysis
Order
Zouros et al,
Phys. Rev. A Rapid Comm. 2008
TIFR Mumbai Mar 9, 2015
Similar results also presented for C4+
Röhrbein et al PRA 2010
Cascade feeding
accounts 70%
for about 50%
of the observed
enhancement
Strohschein PRA 2008
So what is the rest due to?
EXCELLENT QUESTION!
APAPES
Proposal granted!



Investigation of the systematics of the 4P/2P ratio
in an Isoelectronic sequence study using He-like
ions from Li+ , B3+ , C4+ , N5+ , O6+ , F7+ in the
0.1-2 MeV/u
Use different targets such as H2, He, Ne, Ar
Ideally suited to the Demokritos tandem
accelerator energy range of 0.8-5 MV.
In progress:
• Installation of terminal gas stripper to produce
ground state beams
• Installation of post strippers (foil and gas) to
produce He-like ions at lower energies
TIFR Mumbai Mar 9, 2015
New results
2014-2015
APAPES
Comparison
150
Mixed (1s2 + 1s2s 3S)
Gaussian fits
4
P
2
100
P+
12 MeV C4+
Normalized Yields (arb.units)
C4+ + Ne
2
P-
2
S
50
2
D
0
12 MeV C4+
12
C4+ + He
10
8
6
4
2
0
220
225
230
235
240
245
250
Electron Energy (eV)
Similar energy resolution
TIFR Mumbai Mar 9, 2015
Strohschein 2008
New results
2014-2015
Comparison
APAPES
250
Mixed (1s2 + 1s2s 3S)
Gaussian fits
4
P
200
12 MeV C4+
C4+ + Ne
150
Normalized Yields (arb.units)
Strohschein 2008
2
P+
100
2
P-
2
50
S
2
D
0
12 MeV C4+
20
C4+ + He
15
10
5
0
220
225
230
235
240
245
250
Electron Energy (eV)
Our new results look very similar – except for 2-3 times larger 4P!
Reasonable since distance of target 5 times larger
in APAPES - so more time to cascade!
Ratio
comparison
9
4+
New
Results
Give a bit
Too
Low 4P/2P
Ratio!
WMU (4P/2P)
APAPES (4P/2P)
C + Ne
6
4
P/2P
3
spin statistics
0
9
WMU (4P/2P)
APAPES (4P/2P)
4+
C + He
But
much closer
To 2!
6
3
spin statistics
0
0.25
0.50
0.75
1.00
1.25
Incident C4+ Energy (MeV/u)
TIFR Mumbai Mar 9, 2015
1.50
1.75
Consistency Check
ratio 2P+/2P9
4+
WMU (4P/2P)
APAPES (4P/2P)
WMU (2P+/2P-)
APAPES (2P+/2P-)
C + Ne
6
spin statistics
4
spin statistics
0
9
WMU (4P/2P)
APAPES (4P/2P)
WMU (2P+/2P-)
APAPES (2P+/2P-)
4+
C + He
6
3
spin statistics
0
0.25
0.50
0.75
1.00
1.25
Incident C4+ Energy (MeV/u)
TIFR Mumbai Mar 9, 2015
P+/2P-
2
P/2P
3
However
2P+/2Pspin statistics
Ratio seems
Good
1.50
1.75
For all!
More New results
2014-2015
Higher Energy – 18 MeV
New targets
6
6
W=1521eV,F=4,
VL4 =-684.45V,
VL5=1399.32V
Normalized electron Yields (x10-11) (arb.units)
4
Ne
2
0
4
2
4
P
He
2
S
2
2
P- P+ 2D
0
4
3
4
5
Normalized electron Yields ( 10-11)
12 MeV C
4+
Norm.yields
Norm.fit
P
2
18 MeV C4+ W=1966eV, F=4
Ne (20 mTorr)
Fit
4
4
P
2
P+
2
2
2
2
2
P-
S
1
1
D
2
2
S
0
6
P-
P+
2
D
0
3
5
Ar (5 mTorr)
Fit
4
P
Ar (5 mTorr)
Fit
4
P
2
4
3
2
2
P+
2
S
P-
1
2
2
2
S
2
P-
D
P+
2
D
1
0
220
0
225
230
235
240
245
250
0
220
225
230
235
240
245
250
Auger Electron Energy (eV)
4
Ar
2
0
220
Ne (20 mTorr)
Fit
2
3
2
H2
12 MeV C4+ W=1521eV, F=4
225
230
235
240
245
Auger electron Energy (eV)
250
New calculations are needed
to evaluate capture and cascade
contributions for all measured
collision systems
TIFR Mumbai Mar 9, 2015
APAPES ZAPS setup: Single stage 00 HDA with
injection lens and 2-D position sensitive detector
Differential
Pumping
ports
Focusing and
retardation
Target gas
nt ~1012 #/cm3
Paracentric
entry
Faraday Cup
C4+
Chamber pressure
~10-7 Torr
Gas in
4-element lens
Inner
hemisphere
Gas Cell
Pressure Gauge
electrons
PSD
X-Position
Y- Position
Timing
Outer
hemisphere
DE
DE
 0.1%,
E
E
1/11/2007
 20%,
accept
D
 1.5  105
4
Overall efficiency gain ~ 20-50
High Transmission ~ 90%
TIFR Mumbai Mar 9, 2015
PSD and DAQ
Electronics
5-channel
preamp
Acquired via collaboration with ATOMKI - Debrecen
TIFR Mumbai Mar 9, 2015
PSD and DAQ
Electronics
RG-59U (75 Ohm) 0.5MOhm
RG-58U (50 Ohm) 0.4MOhm
RG-174U (50 Ohm)
Grid
MCP
MCP
1
2RAE
1nF
Y2
2MOh
m kOhm
150
Added by B.
Sulik
1
2
3
4
Feed
Resistor chain
through #2
1
2
3
4
1
2
3
4
3.3nF
X1
Y1
2200V
3.3nF
1nF 1nF 1nF
- VMCP
+floating
X2
preamplifier
V2
Y2
X1
Y1
X2
V1
Y2
X1
Y1
X2
4
3
2
1
to PC
Vbias
Vgrid
VL5
VL4
VL VL VL5 VL6
2
FC
+
V
- Bias
0
4
Ion beam
Vp
Feed
through
#1
V
48V
HV panel #2
grid
ground
VL6
VL5
VL4
VL
2V
pV1
V2
TIFR Mumbai Mar 9, 2015
to MHV terminator
to MHV terminator
HV panel #1
Vp=V
L2
V1
V2
VL5
VL4
V1
V2
PSD and DAQ
Sum
signal
4P
X-proj
Y-proj
Projection along energy axis
2-D image on PSD
TIFR Mumbai Mar 9, 2015
Projections
Zero-degree Auger Projectile spectroscopy setups:
1s2s2p 4P yield correction for long-life times
WMU
Our distance s0 is about
5 times larger than in
the WMU setup so its not
Surprising that we measure
More 4P electrons!
s0
s0=5.9cm
APAPES
s0=28.9cm
TIFR Mumbai Mar 9, 2015
Zero-degree Auger Projectile spectroscopy setups:
1s2s2p 4P yield correction for long-life times
APAPES -12 MeV C4+
WMU
-1
Temporal Term FT (mm )
-1
10
J=1/2 =3.7 ns
J=3/2 =13.2 ns
J=5/2 =117.2 ns
-2
10
-3
10
-4
10
-5
10
1
10
-1
10
-2
10
q = qmax
D0(s0-z) (sr)
0
10
-3
10
F7+
-4
10
-2
D0(s0-z) FT(z) (sr/mm)
10
-3
10
-4
10
-5
10
-6
10
τ1/2 = 0.735 ns
-7
10
0
50
100
150
200
250
300
1.1 MeV/u
τ3/2 = 7.88 ns
Z (mm)
τ5/2 = 16.3 ns
TIFR Mumbai Mar 9, 2015
1s2s2p 4P metastable solid angle correction factor –
WMU – two-stage parallel plate Analyser (2PPA)
Important
Yield correction
Factor (x 2.5)
1.1 MeV/u
F7+
τ1/2 = 0.735 ns
For C4+ 4P
correction factors:
7.3, 8.8, 10.2
for 6, 9, 12 MeV
Strohschein PRA 2008
1.1 MeV/u
τ3/2 = 7.88 ns
τ5/2 = 16.3 ns
TIFR Mumbai Mar 9, 2015
1s2s2p 4P metastable solid angle correction factor –
APAPES Hemispherical Deflector Analyzer (HDA)
APAPES
12 MeV C4+
-1
Temporal Term FT (mm )
-1
10
J=1/2 =3.7 ns
J=3/2 =13.2 ns
J=5/2 =117.2 ns
-2
10
-3
10
-4
10
-5
10
1
10
-1
10
-2
10
q = qmax
D0(s0-z) (sr)
0
10
-3
10
-4
10
-2
D0(s0-z) FT(z) (sr/mm)
10
Calculated by
SIMION Monte Carlo
-3
10
-4
10
-5
10
-6
10
-7
10
0
50
100
150
200
250
Our distance s0 is about
5 times larger than in
the 2PPA setup so its not
Surprising that we measure
More 4P electrons!
300
Z (mm)
28.9cm
TIFR Mumbai Mar 9, 2015
SIMION Monte Carlo calculation:
Correction factor for F7+ and C4+
KSU
APAPES
7+
4+
Normalized Electron Yield (Arb. Un.)
25.3 MeV F + H2
12.0 MeV C + Ne
25
20
25
Exp. Data
4
SIMION P J-averaged
4
SIMION P prompt
SIMION prompt states
15
4
20
4
P
2
S
5
Exp. Data
4
SIMION P J-averaged
4
SIMION P prompt
SIMION prompt states
D
P
15
10
2
2
2
10
P+
2
2
S
2
5
P-
0
2
P-
D
0
20
10
4
4
SIMION: PJ states
SIMION: PJ states
Partial contributions
J=1/2  = 0.57 ns
J=3/2  = 1.85 ns
J=5/2  = 15.9 ns
3
Electron Counts (x10 )
P+
15
Partial contributions
J=1/2  = 3.01 ns
J=3/2  = 9.10 ns
J=5/2  = 65.0 ns
8
6
10
4
5
0
510
Submitted to
RSI 2015
2
520
530
540
550
560
0
225
230
Auger Electron Energy (eV)
TIFR Mumbai Mar 9, 2015
235
240
245
SIMION Monte Carlo calculation:
Correction factor for 4 MeV B3+
45000
40000
35000
electron count
30000
25000
4 MeV B3+
prompt, Area = 9870
J = 1/2, Area = 24405
J = 3.2. Area = 43337
J = 5/2, Area = 8430
G1/2 = 24404/9870 = 2.47
G3/2 = 43322/9870 = 4.39
20000
G5/2 = 8421/9870 = 0.85
15000
10000
5000
0
152
153
154
155
156
157
Auger energy (eV)
TIFR Mumbai Mar 9, 2015
158
159
160
18 MeV C4+ SIMION correction factor calculation
Davis Lifetimes
25000
20000
10000
5000
G1/2 = 17653/8683 = 2.02
G3/2 = 41381/8683 = 4.76
G1/2 = 18806/8683 = 2.16
Gall = ((1/6)*1.00*G1/2 +
(2/6)*0.97*G3/2 +
(3/6)*0.99*G5/2)/0.99
= 2.95
Chen Lifetimes
0
222
25000
223
224
225
226
227
228
229
230
231
232
20000
G1/2 = 21673/8683 = 2.49
G3/2 = 42908/8683 = 4.94
G1/2 = 11401/8683 = 1.31
15000
10000
5000
18 MeV C4+
prompt, Area=8683
J = 1/2, Area=21673
J = 3/2, Area=42908
J = 5/2, Area=11401
Rest Frame (eV)
Counts
Counts
15000
18 MeV C4+
prompt, Area=8683
J = 1/2, Area=17563
J = 3/2, Area=41381
J = 5/2, Area=18806
Gall = ((1/6)*0.99*G1/2 +
(2/6)*0.94*G3/2 +
(3/6)*1.00*G5/2)/0.98
= 2.66
0
222
223
224
225
226
227
228
Rest Frame (eV)
TIFR Mumbai Mar 9, 2015
229
230
231
232
Summary and Conclusion
• Controversy still remains:
Corrected 4P/2P ratio either
too large (WMU) or too small (APAPES)!
• New results even more controversial!
Still preliminary – need to be checked further
• More measurements still needed
for different collision systems to
better check systematics (APAPES)
• Follow up cascade calculations
• Tests of corrections to 4P
• Can someone please calculate the
Pauli Exchange Interaction?
TIFR Mumbai Mar 9, 2015
APAPES Future
Experiment - Measurements:
•
•
•
•
More measurements needed
for different collision systems to
better check systematics (present APAPES)
- He-like Ions: Li+, B3+, C4+ , N5+ , O6+ , F7+
- Various targets: H2, He, Ne, Ar, …
- Different energies: 0.2-2 MeV/u
Install terminal gas stripper to also
produce ground state He-like ions
Install gas and foil post-stripper to enable
production of lower energy He-like ions
Investigate other 3-e spin statistics collision
systems such as Be-like (ionization),
Li-like (excitation), etc.
TIFR Mumbai Mar 9, 2015
APAPES Future
Theory - Simulation:
• Tests of solid angle corrections to 4P (use
SIMION Monte Carlo approach on 2PPA
results)
• Follow up cascade calculations for all
measured collision systems
• Include possible alignment due to capture
• Can someone please calculate
Pauli Exchange Interaction?
Open to NEW collaborations!
TIFR Mumbai Mar 9, 2015
APAPES
Main team
• Dept. of Physics, Univ. of Crete, Heraklion
Theo
Zouros
(Prof & PI)
Anastasios Ioannis Angelos
Dimitriou Madesis Laoutaris
(PostDoc)
(PhD student) (MS student)
TIFR Mumbai Mar 9, 2015
APAPES
important participants
Measurements
Manolis
Benis
(Prof)
Bela
Sulik
(Prof)
Dept of Physics
Univ of Ioannina
Greece
ATOMKI
Debrecen
Hungary
Spiros
Doukas
U. Ioannina
SIMION
Omer
Sise
(Prof)
Univ of Isparta
Turkey
Genoveva
Martinez-Lopez
(Prof)
Jose
Paulo Santos
(Prof)
Dept Fisica
Aplicada Madrid,
Dept de Fisica
Univ Nova de Lisboa
Spain
CPO simulations
Zoom lenses
TIFR Mumbai Mar 9, 2015
Portugal
Atomic
Structure
calculations
APAPES
Support Team
5MV Tandem, Institute of Nuclear and Particle Physics
NCSRT Demokritos
Dr. Sotiris
Dr. Tasos
Dr. Michalis
Harissopulos Lagoyannis Axiotis
(Director)
(Res.)
(Res.)
Miltos
Theo
Andrianis Mertzimekis
(Accel. Eng.) (Prof.)
Univ. of
Athens
TIFR Mumbai Mar 9, 2015
The end
thank you for listening
I thank Dr. Lokesh Tribedi
for inviting me
More info? Please Contact me: [email protected]
Acknowledgement: This research has been co-financed by the European Union (European Social Fund
ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of
the National Strategic Reference Framework (NSRF) Research Funding Program: THALES. Investing
in knowledge society through the European Social Fund, grant number MIS 377289.
TIFR Mumbai Mar 9, 2015