1. Commissioning plan for UED@ASTA
Renkai Li
5/20/2014
ALD Review

2. Pre-operation preparation Commissioning plan
Outline
Pre-operation preparation
Commissioning plan
Machine operation and e-beam characterization
Transverse overlap of laser and e-beam
Temporal overlap of laser and e-beam
Summary

3. Pre-operation preparation
Checklist
Safety
Training
Trigger and timing
Equipment protection
Modulator, klystron, LL and high power rf
Alignment
rf gun
Laser
Magnets and power suppliers
Motors/actuators
Cameras
Diagnostics
Data management
Software
preparation checklist

4. Pump-probe control and data acquisition1 D1 S1
e-beam BS D2
sample C2 S2
delay stage
EMCCD
Computer
> 100 M/s
gun
control
delay stage
Shutter S1/S2
acquire
photodiode D1/D2
Virtual pump Camera C2
EMCCD
Computer
transfer
To be built and tested off-line.
Sample holder
trigger

5. Commissioning plan Laser optics installed by July 15th
Beamline installation July 15th – July 31th
Aim to run e-beams starting from August 1st w/o sample chamber

6. Machine operation and e-beam characterization
Most tasks ready by August 1st
Safety
Training
Trigger and timing
Equipment protection
Modulator, klystron, LL and high power rf
Alignment
rf gun
Laser
Magnets and power suppliers
Motors/actuators
Cameras
Diagnostics
Data management
Software
August 1st – 15th
Operation of the machine
e-beam energy, charge, spot size
Stability of e-beam parameters
shot-to-shot fluctuation
long-term (a few hours) stability
August 15th -
Sample holder control
laser and e-beam transverse overlap
laser and e-beam temporal overlap

7. Transverse laser and e-beam overlap
aperture (4-5 mm diameter)
He-Ne
steering coils
laser
e-beam
screen
camera
stage
Sample holder at UCLA
screen
SiN window (broken)
SiN window

8. Temporal laser and e-beam overlap
Steps to find time-zero
1) Fast photodiode D1 and D2 (< 100 ps or 3 cm)
2) Measure the rest of optical path length (~1 cm)
3) time-of-flight of the e-beam (from simulation)
4) Ultrafast plasma lensing effect (<1 ps)
2000 mesh TEM Grid
-8 ps
-4 ps
0 ps
4 ps
8 ps
12 ps
16 ps
20 ps
28 ps
3 MeV beam
up to ~50 J/cm2 L0 L
C. M. Scoby et al., dx.doi.org/ /j.ultramic
400 fs step size
J. R. Dwyer et al., Phil. Trans. R. Soc. A 364, 741 (2006)
H. Park et al., RSI 76, (2005)

9. Summary
Pre-operation preparation (checklist, now – August 1st)
Machine operation / e-beam characterization (August 1st - )
Transverse overlap of laser and e-beam
Temporal overlap of laser and e-beam
Experiment using samples with ultrafast (100 fs) response
Thank you!