Quasiperiodic mode:

The IEX undulator can run in periodic (full flux) or quasiperiodic mode (QP) to reduce higher harmonics contamination. Running in QP mode results in a loss of flux on the first harmonic which varies depending on the energy and polarization. The trade off between harmonic reduction and flux loss can be tuned as needed. The example below displays the results obtain at 700 eV incident energy for a reduction down to 2% of the 2nd harmonic contamination in horizontal polarization. This mode is still in commissioning, so please contact staff in advance to communicate your needs before hand.