MeV-UED Endstations

The SLAC UED system supports multiple different sample chambers optimized for different type of sample delivery. Please note that not all endstations are currently available for the general User Program, e.g., liquid phase chemistry.

Solid State (Materials) & Warm Dense Matter (Single Shot) Endstation
Sample motion 5-axis sample motion
Transverse to beam:
    X (horz): 50 mm (5 um resolution)
    Y (vert): 25 mm (0.1 um resolution)
Along beam:
    Z (horz): 25 mm (5 um resolution)
    Yaw (about Y): +/- 45 degrees
    Pitch (about X): +/- 45 without cooling;
                                    +/- 15 with cooling.
Sample Cooling 30 - 300 K
Diagnostics Frosted YAG for electron/laser overlap
Single-crystal gold for q reference
Si temperature sensor
Bi for time-zero reference
Sample mounting TEM mesh grids
TEM Si3N4 membranes
Si3N4 membrane arrays (contact)
Vacuum <1 x10-7 Torr


UED Gas Phase Endstation
Sample Temperature Range Sample reservoir: RT - 100 °C (flow cell) & RT - 150 °C (pulsed nozzle)
Transport line : RT - 80 °C (flow cell) & RT - 180 °C (pulsed nozzle)
Pulsed nozzles : RT - 200 °C
Flow cell: RT to ~ 100 °C
Sample Vapor Pressure Requirement > 100 torr at 150 °C for pulsed valves
> 0.5 torr at RT for flow cell (3 to 4 mm path length)
Sample Reservoir Size 100 mL (e.g. standard 2.75 CF nipple)
Buffer Gas (optional) Helium, 5 bar for Parker general valve
Nozzle Properties Pulsed, up to 180 Hz
100 - 200 µm orifice
Typical opening time: 100 - 300 µs
Gas Jet Size (FWHM) 200-400 µm
Nozzle motion 3-axis translational motion
X (Horizontal in lab, perpendicular to beam propagation direction): 2"
Y (Vertical in lab): 2"
Z (Horizontal in lab, beam propagation direction): 2"
Cold Trap Temperature < 100 K
Diagnostics Frosted YAG for electron/laser overlap
Single-crystal Au/Si for Q reference and time zero reference (within 400 fs)
Pump-probe propagation angle ~2°
Vacuum Operation condition:
Flow cell operates at 1-10 Torr
Background pressure ~1e-5 - 1e-4
Gas Line Material Stainless Steel
Nozzle Puppet/Seal Materials Vespel (Parker general valve; series 9)
Polyimide (for high repetition rate valves)
Flow cell materials (1) Stainless steel  (2) Macor ceramic
Q range 0.5 to 12  Å-1
Q resolution (FWHM) 0.17  Å-1
Time resolution (FWHM) 150 fs
Pump Wavelength 200 nm, 266 nm, 400 nm, 800nm, 240 nm - 2 µm tunable
Delay Stage Range 2 ns
Delay Stage Resolution 7 fs