Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
FLAC XV
Wir schaffen Wissen – heute für morgen
Commissioning of the Aramis
undulator line @ 3GeV
Marco Calvi
February 2, 2015, Villigen PSI
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Overview
1
 Preparatory work at the MML
 BBA to define the reference orbit
 Commissioning with electron beam
 Alignment of the undulator modules
 Correction of the residual U15 field errors
 Commissioning with photon beam
 Fine-adjustment of the height and pitch
 In situ calibration of the individual K-values
 Pointing direction: checks and corrections
 Setting up of the phase shifters
 FEL signal characterization
 Pulse energy (absolute) and its statistic
 Gain length per module
 Conclusions
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Preparatory work @ MML
2
U15
Optimization of the trajectory and phase of the U15s
Calibration of the K versus gap: gn(K)
Measurements of the residual 1st and 2nd field
integrals versus K: I1n(K) & I2n(K)
 inδn(K) & outδn(K)
Phase Shifter
Optimization of the field integrals
Phase shift versus gap calibration: gn(ϕ)
Alignment Quadrupoles
Check the Gdl and the reproducibility of the
transversal positioning
Magnetic alignment on the U15 axis
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Phase shifter
3
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Alignment Quadrupoles
e-
nf or mat i on
ni cht f r ei gegeben!
6120
4
U- SCH I SO 7090- M5- MS
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Aramis Beam Based Alignment
5
Corrector-based BPM alignment (Aiba & Böge FEL 2012)
 Procedure
 Steer the beam to the centres of BPMs and record the corresponding
corrector strengths (strong correction indicates large misalignments)
 Find BPM positions that minimise the deviation of corrector strengths
 Corrector strengths will be all zero if no misalignments and no error field
 A running orbit feedback simplify the above procedure
 Features
 Random error field dependent
(undulator error fields must be small)
 No momentum change is required and
thus quick
Corrector strengths must be the
same value for periodic line
Villigen PSI
 Alignment of the undulator modules
 Correction of the residual U15 field errors
Marco Calvi
FLAC XV
 Preparatory work at the MML
 Run BBA to define the reference orbit
 Commissioning with electron beam
February 2, 2015
Overview
6
 Commissioning with photon beam
 Fine-adjustment of the height and pitch
 In situ calibration of the individual K-values
 Pointing direction: checks and corrections
 Setting up of the phase shifters
 FEL signal characterization
 Pulse energy (absolute) and its statistic
 Gain length per module
 Conclusions
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Undulator alignment
7
Undulator modules
1
2 …
n
n+1 … 12
13
e-
gap
BPMs
Alignment Q
Villigen PSI
Undulator alignment
U15n+1
U15n
Marco Calvi
FLAC XV
February 2, 2015
BPMn
8
BPMn+1
reference orbit
z
Villigen PSI
Undulator alignment
U15n+1
U15n
Marco Calvi
FLAC XV
February 2, 2015
BPMn
9
BPMn+1
reference orbit
Orbit perturb
ation
z
Villigen PSI
Undulator alignment
U15n+1
U15n
Marco Calvi
FLAC XV
February 2, 2015
BPMn
10
tion
a
b
r
u
t
er
Orbit p
BPMn+1
reference orbit
z
 The upstream & the downstream alignment quadrupoles can be
used independently to define the x & y positions at the two extremes
 Later the x , y , pitch & yaw position of the U15 module can be
calculated and the undulator moved to the new position
 Finally the alignment quadrupole can still be used to check and to
verify the stability with time
Villigen PSI
Field Error Corrections
Undulator modules
1
2 …
n
n+1 … 12
13
e-
Marco Calvi
FLAC XV
February 2, 2015
gap
11
BPMs
Villigen PSI
Field Error Corrections
U15n+1
U15n
BPMn
Marco Calvi
FLAC XV
February 2, 2015
BPMn+1
12
reference orbit
L1
L2
z
U15n+1
U15n
BPMn
ation
b
r
u
t
r
e
Orbit p
BPMn+1
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Field Error Corrections
13
reference orbit
L1
L2
BPM n+1 ( K ) - BPM n ( K )
I1n ( K ) =
L2
I 2n ( K ) = BPM n ( K ) - I1n ( K ) L 1
z
Villigen PSI
 Alignment of the undulator modules
 Correction of the residual U15 field errors
Marco Calvi
FLAC XV
 Preparatory work at the MML
 Run BBA to define the reference orbit
 Commissioning with electron beam
February 2, 2015
Overview
14
 Commissioning with photon beam
 Fine-adjustment of the height and pitch
 In situ calibration of the individual K-values
 Pointing direction: checks and corrections
 Setting up of the phase shifters
 FEL signal characterization
 Pulse energy (absolute) and its statistic
 Gain length per module
 Conclusions
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Photon diagnostic
15
Photo
Diode
FE Slits
FS
CCD
γ
MCP
Monochromator
Front end slits for shaping the white beam
Double crystal monochromator (2.1-20.0keV)
with a bandwidth of about 10-4
Photo diode for pulse energy
MCP for low intensity pulse and profile monitor
Villigen PSI
Height and pitch adjustment
Undulator modules
1
Marco Calvi
FLAC XV
February 2, 2015
gap
16
2 …
n
… 13
γ
e-




Set all undulator at open gap
Set the undulator n at K=1.2
Set the monochromator at E(K)
Move the undulator height around
the nominal position and measure
the photon flux
 K=K0+αh2
 The axis is defined by the magnetic
field symmetry
 If the g(K) relation is correct the axis
has also the highest photon flux
T.Tanaka et al. Phys. Rev. ST Accel. Beams 15,
2012
Villigen PSI
g(K) value calibration
Undulator modules
1
Marco Calvi
FLAC XV
February 2, 2015
gap
17
2 …
n
… 13
γ
e-




Set all undulator at open gap
Set the module n at K
and the monochromator at E(K)
Move the undulator gap around the
nominal value while recording the
photon flux
 When the blue edge of the spectrum
is well characterized the actual gap
shall be extracted using empirical
fits
T.Tanaka et al. Phys. Rev. ST Accel. Beams 15, 2012
Villigen PSI
g(K) value calibration
square aperture
:
0.25 mm2
Marco Calvi
18
2.0
4.0
8.0
16.0
mm
mm
mm 2
mm
2
2
2
mm 2
32.0
distance from the observer (m)
observer
1.0
ΔKerror /K (×10-4)
FLAC XV
February 2, 2015
drift section
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Photon pointing direction
19
Undulator modules
1
2 … n
… 13
γ
CCD
e Set all undulator at a given K value
 Shift the module n to K+ΔK
 and set the monochromator at the
energy E(K+ΔK)
 Use MCP+FS respectively to amplify
and detect the profile of the pulse on
a CCD
 This procedure shall be repeated for
all modules (and eventually also for
different K)
 The steering magnets shal be tuned
to improve the overlap of the
different sources
T.Tanaka et al. Phys. Rev. ST Accel. Beams 15, 2012
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Setting the Phase Shifters
20
Undulator modules
1
2 …
n
n+1
n+1
… 13
γ
e-
Phase Shifter
 Set all undulator at open gap
 Close the modules n and n+1 at K
 Set the monochromator at the
energy E(K)
 Change the phase shift between
from maximum to minimum
 This procedure shall be repeated for
all phase shifter modules (and
eventually also for few different K)
T.Tanaka et al. Phys. Rev. ST Accel. Beams 15, 2012
Villigen PSI
 Alignment of the undulator modules
 Correction of the residual U15 field errors
Marco Calvi
FLAC XV
 Preparatory work at the MML
 Run BBA to define the reference orbit
 Commissioning with electron beam
February 2, 2015
Overview
21
 Commissioning with photon beam
 Fine-adjustment of the height and pitch
 In situ calibration of the individual K-values
 Pointing direction: checks and corrections
 Setting up of the phase shifters
 FEL signal characterization
 Pulse energy (absolute) and its statistic
 Gain length per module
 Conclusions
Villigen PSI
Pulse energy
Undulator modules
…
22
11
12
13
γ
e-
9
2
total intensity
 All undulator set at a given K
value (eventually with a taper)
 Record the pulse energy on a
single slot base
 Build up the statistic:
 Average pulse energy (mJ)
 Number of excited modes
x 10
1.5
1
0.5
0
500
1000
1500
2000
2500 3000
shot no.
3500
4000
4500
5000
400
histogram
fit with M=136
fit with M=208
300
number
Marco Calvi
FLAC XV
February 2, 2015
1
2
200
100
0
0.7
0.8
0.9
1
1.1
1.2
1.3
intensity
1.4
Courtesy of E.Prat
1.5
1.6
1.7
9
x 10
Villigen PSI
Gain Length
1
2
γ
Marco Calvi
23
Proceedings of F
Active undulator length
D.Ratner, Proceedings of the FEL2009, Liverpool, UK
 Set all undulator at open gap
 Close the first module to K and
record the average photon flux
 Close also the second to K and
record the average photon flux
 ….
 Repeat until all the modules are
closed to K
FEL power (W)
FLAC XV
February 2, 2015
e-
10
10
10
8
10
6
measurements (04/26/09)
GENESIS simulation
0
20
40
60
Active undulator length (m)
80
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Conclusions
24
The general ideas for the commissioning of
the Aramis undulator line have been
presented
A preliminary procedure has been internally
discussed among different groups
and the hardware as well as the timing have
been verified
In the coming months a more detailed
procedure shall be written down and finally
approved
Marco Calvi
FLAC XV
February 2, 2015
Villigen PSI
Thanks for your attention!
25