MeV-UED Specifications

Scientific Capabilities

Scientific Application  Technique
Time-resolved measurement of electron–phonon coupling Measurement of Debye-Waller effect on multiple lattice reflections
Time-resolved studies of momentum resolved phonon dynamics Thermal diffuse scattering measurement
Measurement of melting dynamics Single-shot pump–probe measurements
Three dimensional measurement of structural dynamics Measurements of positional change of multiple lattice reflections at different sample orientations
Measurement of chemical photodissociation or photoisomerization Gas-jet UED
Measurement of novel phase of quantum materials Cryo-UED

Source Parameters

Parameter Value
Electron beam energy 2 - 4 MeV
Repetition rate Single shot → 360 Hz*
Charge per pulse 1 - 100 fC (104 - 106 electrons)
Beam emittance 2 - 20 nm-rad
Bunch length <150 fs FWHM**
Momentum resolution <0.17Å-1
Beam spot size 100-200 um (typical), 10 um (FWHM) focused

*Upgrade planned in 2022
**Beam charge dependent

Optical Laser Properties

Parameter Value
Repetition rate Single shot → 360 Hz
Wavelength range 200 nm, 266 nm, 400 nm, 800nm, 240 nm - 2 µm tunable, 3-15 µm tunable
Typical optical pulse energy > 8 mJ @ 800 nm
> 0.8 mJ @ 400 nm
> 0.08 mJ @ 266 nm
~ 16  µJ @ 200 nm
For pulse energies at specific wavelengths (e.g. 260 nm – 750 nm) or other details please contact Patrick Kramer
Nominal pulse duration 75 fs (FWHM)
Optical delay 0 - 3 ns (physical delay stage)
Optical spot size 200 - 1500 µm (FWHM)

Detectors

P43 phosphor screen & Andor iXon Ultra 888 EMCCD
Phosphor thickness 50-100 um
Point-spread-function 85 um (rms)
Pixel size 13 x 13 um2
Sensor size 1024 x 1024
Data format .tiff
Pixel well depth 80k e-
ePIX detector - direct electron detection*
Pixel size 100 x 100  um2
Frame rate 360 Hz
Sensitive area 5 x 5  cm2
Gain mode 3 fixed plus 2 with auto ranging and programmable switch point
S/N in High Gain per MeV electron >100

*Offered under a commissioning/best-effort basis. Contact UED staff for details.