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Research Contents > Beamlines > TEMPO > Detailed beamline description > ExpStation1
UHV Photoemission
The main branch of the TEMPO beamline is equipped with a UHV system for surface science experiments. It is composed by a main chamber equipped with a Scienta SES 2002 electron energy analyzer (equipped with a delay line detector) and a preparation chamber with a sample transfer system and a fast entry lock. Ar- sputtering, water cooled evaporators and LEED characterization are available. We have developed two sample environments: one for magnetic dichroism experiments where about 100 Oersted can be applied in the measuring position and one for direct heating of semiconductor samples by current flow.
 
The UHV Photoemission experimental station in 2008
Detector For Time Resolved experiments
An important part of the TEMPO beamline scientific project is based on time resolved photoemission experiments performed using a pump probe technique. Possible applications are to studies of the electronic structure of laser excited states or the dynamics of surface magnetization.
The relaxation time of these phenomena can be longer then the interbunch period. It is then indispensable to associate each detected photoelectron to the synchrotron bunch which created it. If this identification is possible , then each repetition rate of the pump can be used for the experiments and the state excited by the laser pump can be probed by the Syncrotron Radiation pulse as a function of the delay t between the two pulses.
The time resolution of the experiment is then limited only by the S.R. pulse width: 30 ps at SOLEIL
We modified the Scienta SES 2002 electron energy analyser by replacing the CCD Camera by a delay line detector (G.Cautero and coworkers, Elettra, Trieste, It) which can associate each detected photoelectron to the Soleil Clock. This new configuration allows us to perform photoelectron spectroscopy experiments using the isolated bunch when Soleil is injected in hybrid mode.

In the picture the photoemission intensity measured as a function of time on a revolution period (about 1.2 μs) is compared to the Soleil bunch structure during a run in hybrid mode.


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