The photon sources for the MAX IV beamlines are based on Insertion Devices (ID) that cover the photon energy range from 4- 40 000 eV at the three accelerators. The soft x-ray beamlines at the 1.5 GeV and 3 GeV rings are based on APPLE II type undulator, except FlexPES, to provide full polarization control at the fundamental harmonic. A room temperature In-vacuum undulators (IVU) are the sources for the hard x-ray beamlines at the 3 GeV ring and Short Pulse Facility (SPF).

All IDs are delivering light up to specifications at the current 16 beamlines at MAX IV, and continuous improvement is being made to enable operation excellence, such as motion upgrade, introducing the continuous photon energy scanning modes of operation at the different beamlines, and transparent operation in terms of the effect on the electron beam orbit and optics. 

We have recently finished characterizing a full-scale APPLE X prototype undulator with a compact structure intended for use at single-pass machines and fourth-generation storage rings where a small round vacuum chamber can be accommodated. It is part of the enabling technology development for the future upgrade of the 3 GeV ring and soft X-ray FEL at MAX IV as a source with full polarization control. The compactness of its structure considerably reduces the overall cost by 40 % and the weight by a factor of 6 compared to an APPLE II undulator with similar parameters.  

Another direction in ID development involves implementing a Cryogenic Permanent Magnet Undulator (CPMU) technology to achieve a shorter period undulator of the order of 13–14 mm. This short-period CPMU is designed to leverage the emittance reduction from the proposed 3 GeV ring upgrade, serving as a source of high coherent flux and brilliance for photon energies up to 65 keV. 

Photon Sources Development Plan 

Short Term Planning (1-2 years) 
  1. Design review of APPLE X prototype undulator, documentation, and publication. 
  2. Machine learning of ID orbit correction, testing, and deployment. 
  3. Detailed design of Insertion devices for WISE beamlines and MedMAX. 
  4. Full ID integration in J5, maintenance, and spare parts. 
  5. Expand ID-mono Continuous scanning scheme to interested beamlines.  
Medium Term Planning (3-4 years) 
  1. Production, installation, and commissioning of cryogenic permanent magnetic undulator(s) for Tomography and MedMAX beamlines. 
  2. Production, installation, and commissioning of 3T 3-pole wiggler for Tomography beamline. 
  3. Production, installation and commissioning of room temperature in-vacuum undulator for the tender hard x-ray beamline. 
  4. APPLE II undulator for FlexPES beamline. 
Long Term Planning (>4 years) 
  1. Optimize the ID design to fit MAX 4U requirements (e.g., BALDER wiggler, IVUs, round gap APPLE type ID). 
  2. Replacement of existing IVU’s and EPU’s ~15 years old based on an assessment of magnet degradation and mechanical/motion parts degradation.