|
- C. Benabderrahmane, P. Berteaud, N. Béchu, L. Chapuis, M.-E. Couprie, J.P. Daguerre, J.-M. Filhol, C. Herbeaux, A. Lestrade, M. Louvet, J.L. Marlats, K. Tavakoli, M. Valléau, D. Zerbib
SOLEIL, Gif-sur-Yvette, France
|
|
|
Short period, high field undulators can enable short wavelength FEL at low beam energy, with decreased gain length, thus allowing much more compact and less costly FEL systems. A R&D programme for the construction of a 2 m long 18 mm period CPMU is under progress at SOLEIL. The use of PrFeB which features a 1.35 T remanence (Br) at room temperature enables to increase the peak magnetic field at 5.5 mm minimum gap, from 1.04 T at room temperature to 1.15 T at a cryogenic temperature of 77 K. For FELs, we can reach higher magnetic field of 1.91 T at lower gap of 3 mm. Pr was chosen instead of Nd magnetic material, because of the no appearance of the SRT phenomenon. Different corrections were performed first at room temperature to adjust the phase error, the electron trajectory and to reduce the multipolar components. The mounting inside the vacuum chamber enables the fitting of a dedicated magnetic measurement bench to check the magnetic performance of the undulator at low temperature. The results of the magnetic measurements at low temperature and the comparison with the measurement at room temperature are reported. A U18 CPMU will be used in LUNEX5 project at SOLEIL.
|
|