Transcript Melanie Mucke

Experiments with
magnetic bottles
Melanie Mucke
Department of Physics and Astronomy
Uppsala University, Sweden
([email protected])
outline
part 1: magnetic bottle spectrometer
• working principle
• layout
• features
part 2: synchrotron experiments
• coincidences
• ICD in water clusters
part 3: FEL experiments
• covariance technique with neon
• double core holes in hydrocarbons
• pump-probe on thymine
part 1: magnetic bottle
magnetic bottle – the beginning
Kruit and Read, J. Phys. E 16, 313 (1983):
cylindrical poles of electromagnet around interaction region,
drift tube with coild around for homogeneous guiding field,
detector: MCP + phosphor screen
strong magnetic field Bi
weak magnetic field Bf
v
qf
v
e-
qi
z
e-
magnetic bottle - principle
Bi
Lorentz force
𝐿 = 𝑒𝑣 × 𝐵
v
angular frequency of motion
qi
𝜔𝑖 = 𝑒𝐵𝑖 /𝑚
orbit (cyclotron radius)
𝑚𝑣𝑖
𝑟𝑖 =
= 𝑣 𝑠𝑖𝑛𝜃𝑖 /𝜔𝑖
𝑒𝐵𝑖
angular momentum of circular motion
𝑙𝑖 = 𝑟𝑖 𝑚𝑣𝑖 = 𝑚
2 𝑣 2 𝑠𝑖𝑛2 𝜃
𝑖
𝑒𝐵𝑖
Bf
v
qf
magnetic bottle - principle
Bi
Lorentz force
𝐿 = 𝑒𝑣 × 𝐵
v
angular frequency of motion
qi
𝜔𝑖 = 𝑒𝐵𝑖 /𝑚
orbit (cyclotron radius)
𝑚𝑣𝑖
𝑟𝑖 =
= 𝑣 𝑠𝑖𝑛𝜃𝑖 /𝜔𝑖
𝑒𝐵𝑖
Bf
adiabatic transition
qf
sin 𝜃𝑓
𝐵𝑓 1
= ( )2
sin 𝜃𝑖
𝐵𝑖
𝑟𝑓
𝐵𝑖 1
= ( )2 = 𝑀
𝑟𝑖
𝐵𝑓
angular momentum of circular motion
𝑙𝑖 = 𝑟𝑖 𝑚𝑣𝑖 = 𝑚
v
2 𝑣 2 𝑠𝑖𝑛2 𝜃
𝑖
𝑒𝐵𝑖
e.g. Bi = 1 T, Bf = 1 mT  qf,max = 1.8°, M = 31.6
magnetic bottle – as used
replace electromagnet by permanent magnet  increase solid angle from 2p to 4p
e-
e-
permanent magnet
inhomogeneous, strong field (0,4 T)
solenoid
homogeneous, weak field (0,5 mT)
magnetic bottle – special features
•
•
•
•
time-of-flight spectrometer – cover full kinetic energy range
high transmission over large kinetic energy range
high detection efficiency
capable of multi particle detection
 ideally suited to investigate correlation between electrons
part 2: experiments at BESSY
time of flight spectra
 need pulsed light source
 need start signal
 need to calibrate
BESSY II
rep. rate 1.25 MHz
= 800.5 ns revolution time
hn = IR … 10 kV
d = 76 m
one electron bunch
approx. 20 mA
experimental setup
synchrotron radiation
magnetic tip
mesh
cluster beam
joint project with AG Becker, FHI Berlin
flight tube (0.6 m)
with homogeneous
magnetic field
detector flange
with MCP stack &
phosphor screen
water clusters
... between molecule and liquid
B. Hartke, Angew. Chem. Int. Ed. 41, 1468 (2002).
Intermolecular Coulombic Decay
continuum
binding energy (eV)
12,85
- 19,11
outer valence
33,37
inner valence
core level
monomer
energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).
Intermolecular Coulombic Decay
continuum
12,85
- 19,11
binding energy (eV)
33,37
outer valence
11,91
- 19,74
inner valence
32,59
- 34,10
core level
monomer
dimer
energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).
Intermolecular Coulombic Decay
continuum
12,85
- 19,11
binding energy (eV)
33,37
outer valence
11,91
- 19,74
inner valence
32,59
- 34,10
core level
monomer
dimer
energies for water follow I. Müller and L. Cederbaum, JCP 125, 204305 (2006).
ICD in water clusters
calculation for water tetramer
energy spectrum of the ICD-electron:
I. Müller and L. S. Cederbaum, JCP 125, 204305 (2006).
photoelectron spectrum of water
inner valence
outer valence
cluster
contribution
S. Barth et al., JPC A 113, 13519 (2009).
photoelectron spectrum of water
inner valence
This state can
decay via ICD.
outer valence
cluster
contribution
+ ICD electrons
S. Barth et al., JPC A 113, 13519 (2009).
electron-electron coincidence
measurement
fast
electrons undistinguishable
sort by flighttime
flight time electron 1
investigate coincident
electron pairs
flight time electron 2
slow
neon tof-map
time-to-energy conversion
flight time electron 2
flight time electron 2
flight time electron 1
2
 D 
  E0
E  
 t  t0 
flight time electron 2
coincidence maps of water
energy map
flight time e2
kinetic energy e1
flight time e1
tof map
kinetic energy e2
hn = 45 eV
ICD spectrum
energy spectrum
shows ICD
0
 qualitative agreement
with theoretical spectrum
expected range
for water ICD
hn = 45 eV
<N> = 40
spectrum of the intermediate state
0
energy spectrum of
the primary electrons
vs. kinetic energy
hn = 45 eV
<N> = 40
spectrum of the final state
0
coincident intensity
vs. binding energy of
the final state
DIP H2O monomer
hn = 45 eV
<N> = 40
variation of the excitation energy
• ICD feature shifts with
photon energy
• energy of the ICD
electron follows the
theoretical predictions
M. Mucke et al., Nature Phys. 6, 143 (2010)
no ICD in the monomer
cluster
monomer
hn = 60 eV
<N> = 200
M. Mucke et al., Nature Phys. 6, 143 (2010)
part 3: experiments at the LCLS
LCLS start
injector
Experiment
and UV laser
~1500 m
large collaborations at LCLS
Uppsala University
M. Mucke
V. Zhaunerchyk
M. Kaminska
M.N. Piancastelli
J.H.D. Eland
(also Oxford University)
R. Feifel
Stockholm University
P. Salén
P. v.d.Meulen
P. Linusson
R.D. Thomas
M. Larsson
Imperial College London
R.J. Squibb
(now Uppsala University)
M. Siano
L.J. Frasinski
ELETTRA Trieste
R. Richter
K.C. Prince
MPI, Heidelberg
L. Foucar
J. Ullrich
Michigan University
T. Osipov
L. Fang
B. Murphy
N. Berrah
SLAC
R. Coffee
M. Glownia
J. Cryan
M. Messerschmidt
S. Schorb
C. Bostedt
J. Bozek
Tohoku University, Sendai
K. Motomura
S. Mondal
K. Ueda
Hiroshima University
O. Takahashi
S. Wada
a new bottle...
experiments at the LCLS
AMO hutch
High Field Physics chamber
Aug/Sep 2011
spectrometer axis
FEL beam
rep. rate 120 Hz
sample beam
experimental set-up
online display
solenoid
magnet
ee-
FEL sample
MCP
digitiser
trigger
from FEL
pulse parameters
covariance analysis
• difference in correlated and uncorrelated products
of electron signals X and Y at two kinetic energies:
C(X,Y) = <XY> - <X><Y>
L.F. Frasinski et al., Science 246, 1029 (1989).
• jitter corretion (photon energy fluctuation)
• partial covariance corrects for intensity fluctuations
of FEL:
Cp(X,Y;I) = C(X,Y) - C(X,I)C(I,Y)/C(I,I)
L.F. Frasinski et al., J. El. Spec. Rel. Phenom. 79, 367 (1996).
• conditional covariance: groupwise analysis of data
from shots of similar intensity
V. Zhaunerchuk et al., Phys. Rev. A 89, 053418 (2014).
Double Core Holes
creation of two core holes in a molecule by photon impact
at the same atom
ss DCH
increased orbital
relaxation effect
at different atoms
ts DCH
high sensitivity to
chemical environment
from L.S. Cederbaum et al., Chem. Phys. 85, 6513 (1986).
recent studies on DCHs
synchrotron radiation +
multi-particle coincidence
CH4
NH3
FEL + single-electron detection
C 1s-2
N 1s-2
J.H.D. Eland et al., Phys. Rev. Lett. 105, 213005 (2010),
P. Lablanquie et al., Phys. Rev. Lett. 106, 063003 (2011),
P. Linusson et al., Phys. Rev. A 83, 022506 (2011),
P. Lablanquie et al., Phys. Rev. Lett. 107, 193004 (2011),
M. Nakano et al., Phys. Rev. Lett. 110, 163001 (2013),
L. Hedin et al., J. Chem. Phys., submitted (2013).
L. Fang et al., Phys. Rev. Lett. 105, 083005 (2010),
J. Cryan et al., Phys. Rev. Lett 105, 083004 (2010),
N. Berrah et al., PNAS 108, 16912 (2011),
P. Salén et al., Phys. Rev. Lett. 108, 153003 (2012),
M. Larsson et al., J. Phys. B 46, 164034 (2013).
study of DCHs at FELs
use efficient electron spectrometer,
employ covariance technique
 make up for low repetition rate of FEL pulses by
• allowing for multiple ionisation events per light pulse
• using a spectrometer of high detection efficiency
• being able to handle multiple electrons per ionisation
event
study of DCHs at FELs
use efficient electron spectrometer,
employ covariance technique
 make up for low repetition rate of FEL pulses by
• allowing for multiple ionisation events per light pulse
• using a spectrometer of high detection efficiency
• being able to handle multiple electrons per ionisation
event
”core hole clock”:
FEL pulse length vs. core hole lifetime
 get information on ionisation dynamics
neon: ionisation processes
photon energy
1062 eV
neon: covariance map core-region
FEL parameters
40 pC charge mode
0.35 mJ pulse energy
≤ 10 fs pulse length
1062 eV photon energy
jitter corrected
raw data
V. Zhaunerchyk, M. Mucke,…, and R. Feifel, J. Phys. B 46, 164034 (2013).
Fourier deconvolution
disciminated data
neon: covariance map correction
neon: coincidence vs. covariance
coincidence
covariance
V. Zhaunerchyk, M. Mucke, et al., J. Phys. B 46, 164034 (2013).
neon: covariance map core-region
FEL parameters
40 pC charge mode
0.35 mJ pulse energy
≤ 10 fs pulse length
1062 eV photon energy
neon: covariance map core-region
FEL parameters
40 pC charge mode
0.35 mJ pulse energy
≤ 10 fs pulse length
1062 eV photon energy
1
1 PAP
2 PP or PAPAP
3 PAPVP, PPVAP or PAPsat
4 PAPAP
5 DKV
6 DKVAP
5
6
3
4
2
neon: covariance maps
core-valence region
core-core region
7
1
5
6
3
4
2
8
1
6
3
1 PAP
4
2
2 PP or PAPAP
5
3 PAPVP, PPVAP or PAPsat
4 PAPAP
5 DKV
6 DKVAP
7 PVP
8 PAPVP or PPVAP
 first time distinguish PPV from PVP
L.J. Frasinski et al., Phys. Rev. Lett. 111, 073002 (2013), V. Zhaunerchyk et al., J. Phys. B 46, 164034 (2013).
Double Core Holes in
hydrocarbons
These slides have been deleted since the results are not yet published.
If you want information on the outcomes of our investigation of double
core hole states in hydrocarbons (C2H2 and C2H6) at the LCLS, please
contact me ([email protected]).
summary on Double Core Holes
• 2dim covariance well suited for analysis of
data from low repetition-rate light sources
(handling of multiple ionisation events per
light shot possible)
• identification of new few-photon processes by
electron kinetic energies and comparison of
intensity dependency of electron-pair features
• clear signatures for DCHs
ultrafast processes in thymine
... investigated by pump-probe spectroscopy
Dt
UV pump + XFEL probe
magnetic bottle
Auger difference spectra
thymine collaboration
Nora Berrah, WMU
Christoph Bostedt, LCLS SLAC
John Bozek, LCLS SLAC
Phil Bucksbaum, PULSE SLAC
Ryan Coffee, LCLS
James Cryan, PULSE SLAC
Li Fang, WMU
Joe Farrell, PULSE SLAC
Raimund Feifel, Uppsala University
Kelly Gaffney, PULSE SLAC
Mike Glownia, PULSE SLAC
Markus Guehr, PULSE SLAC, Spokesperson
Todd Martinez, PULSE SLAC,
Brian McFarland, PULSE SLAC
Shungo Miyabe, PULSE SLAC
Melanie Mucke, Uppsala University
Brendan Murphy, WMU
Adi Natan, PULSE SLAC
Timur Osipov, WMU
Vladimir Petrovic, PULSE SLAC
Sebastian Schorb, LCLS SLAC
Thomas Schultz, MBI, Berlin
Limor Spector, PULSE SLAC
Francesco Tarantelli, Univ. Perugia
Ian Tenney, PULSE SLAC
Song Wang, PULSE SLAC
Bill White, LCLS SLAC
James White, PULSE SLAC
Early Career Grant
Reference: McFarland et al.
Nature Comm. 5, 4235 (2014)
competing processes
GS>pp*
n
Barrier?
UV pump
p
4.5 eV
p*
Potential energy
np*
Asturiol et al., J. Phys. Chem. A,113, 10211 (2009)
Hudock et al., J. Phys. Chem. A,111, 85 (2007)
pp*
np*
Ground
state
Reaction coordinate
pump-probe scheme
Ekin
p*
n
GS
p
SXR probe
Dicationic
states
IP
GS>pp*
UV pump
Core ionized
states
Auger decay
Ekin
SXR probe
Potential energy
np*
Barrier?
UV pump
pp*
Oxygen 1s
CI
np*
CI
Ground
state
Reaction coordinate
Neutral
states
O
UV pump
O
Delay
X-ray probe Auger decay
Auger difference spectra
UV pump: 266 nm
XFEL probe: 570 eV
retardation 470 V
Difference signal: UV On-UV Off
UV Pump Off
UV Pump On
p* Auger
Electrons
Auger difference spectra
Difference signal: UV On-UV Off
UV Pump Off
UV Pump On
p* Auger
Electrons
kinetic energy [eV]
blue-shift of Auger lines
III
II
I
delay [ps]
min
III
II
kinetic energy [eV]
I
McFarland et al, Nature Comm. 5, 4235 (2014)
blue-shift of Auger lines
delay [ps]
min
UV pump
Potential energy
III
pp*
np*
II
I
min
Ground
state
Reaction coordinate
III
II
kinetic energy [eV]
I
McFarland et al, Nature Comm. 5, 4235 (2014)
no barrier observed
delay [ps]
II
I
min
UV pump
Potential energy
III
pp*
np*
Ground
state
Reaction coordinate
III
II
kinetic energy [eV]
I
McFarland et al, Nature Comm. 5, 4235 (2014)
54
the end
magnetic bottle spectrometer –
versatile tool for detection of electrons,
especially suitable for correlation studies