The intense X-ray light for each of the MAX IV beamlines is generated when fast electrons fly through an array of magnets, placed in a so-called insertion device. In a recent report, our insertion device team present the commissioning results for the first nine of these beamline specific instruments.
At synchrotrons like MAX IV, we accelerate electrons to velocities close to the speed of light. The electrons are injected into storage rings where they travel turn after turn inside a vacuum tube, guided by the strong forces of hundreds of carefully tuned magnets. At certain places along the electron path, the magnets are arranged in arrays called insertion devices that make the electrons wiggle from side to side as they fly through. When the electrons perform this motion, they emit energy in the form of intense X-rays. Each beamline needs its dedicated insertion device, built to produce X-rays optimised for the measurement techniques performed there.
The insertion device team have now published the first commissioning results. At the time the report was written, twelve insertion devices were installed, and nine successfully commissioned to deliver according to specifications. Six of them have been built in-house, and two are transferred from the old MAX-lab and refurbished. The remaining insertion devices come from Hitachi and our French synchrotron colleague SOLEIL.
– We have established a good procedure for commissioning, says MAX IV insertion device expert Hamed Tarawneh, and it has been very rewarding for us in the insertion device team as we get to work close with both the accelerator team and the beamline teams.
The paper also shows that the effects of insertion devices on the electron beam orbit have been locally neutralized and the ability to efficiently inject electrons into the storage rings was preserved. This is important as our normal operation mode for the storage rings is so-called top-up with new injections every 30 minutes. In a storage ring, electrons are always continuously lost when they deviate from their path and collide with the vacuum tube due to interactions with other electrons and the few gas molecules left inside. Top-up is a way to compensate for lost electrons to keep the number of electrons more constant, and thereby deliver an even light intensity to the beamlines.
Now the work continues to install even more insertion devices, as we for example reported for SoftiMAX in an earlier news story.
– It has been extremely exciting to install and commission the first insertion-devices around the state-of-the-art MAX IV storage rings and see the results. We are really in a new era, concludes Hamed Tarawneh.
First commissioning results of phase I insertion devices at MAX IV Laboratory
Tarawneh, Hamed; Thiel, Andreas & Ebbeni, Mohammed
(2019) In AIP Conference Proceedings 2054, 030023