Streched bunches live longer

Modern synchrotron radiation sources form very tight electron beams because this increases the brightness of the X-ray beams they generate. The downside is that in these dense bunches the electrons scatter from one another and thus can be kicked out of the acceptance and are lost (Touschek Effect).

What can you do about this? You can make the electron bunches longer to reduce the electron density. For this, modern synchrotrons all use additional RF-cavities with frequencies on a higher harmonic of the frequency of the accelerating cavity. They are called high harmonic cavities.

RI recently received the order for five such 1.5 GHz 3rd harmonic cavities to be used in the BESSY II and the Metrology Light Source storage rings at Helmholtz-Zentrum Berlin. These cavities have been designed by a team of the ALBA Synchrotron in Spain and have been tested in a collaboration between ALBA, DESY, and HZB at BESSY II. They will significantly increase the lifetime of the electrons and thus contribute to brighter and more stable x-ray beams for the users.

We have now started the final manufacturing design and will start the actual production next year. Stay tuned for updates!