Optical Beam Diagnostics

The diagnostic table
diagnostic table

The beam enters the diagnostic station from either the U27 (bottom) or U100 undulator (right hand side).  A part of the beam is separated by means of a beam splitter (10) for power monitoring and wavelength measurement using a Czerny-Turner type spectrometer (2-6). The monochromator is equipped with a 48-channel pyroelectric linear detector array (5). When analysing the spontaneous undulator radiation, which is by 6 orders of magnitude weaker than the laser radiation, the beam splitters (10) are replaced by mirrors. The more sensitive measurements can be performed by Hg-Cd-Te or Ge-Ga detectors using a second exit slit.

The repetition rate of the IR light pulses can be reduced from the 13 MHz down to 2 kHz-1 Hz by means of a semiconductor plasma switch (11) excited by a synchronized Nd:Vanadate laser/amplifier system (8). The pulse power can continuously be reduced by an attenuator (9) by 3 - 38 dB. A polarization rotator (12) consisting of three metall mirrors as installed at FELIX allows the polarization to be changed from horizontal to vertical.

A second-order autocorrelator setup (13) measures the pulse length.
The macropulse signal and the micro pulse signal will be available for triggering and synchronization.

This laboratory as well as the other user labs will be equipped with PCs under Windows NT 4.0 or LINUX. They will have IEEE 488, RS 232/485 interfaces, MIO-Boards and a 100BaseT card. Applications may be developed with LabView resp. BridgeView.