FEL2011 - List of Keywords (cryogenics)

Paper	Title	Other Keywords	Page
THOAI1	Pushing the Limits of Short Period Permanent Magnet Undulators	undulator, vacuum, permanent-magnet, FEL	435
	J. Bahrdt HZB, Berlin, Germany
	Short period undulators to be used as FEL radiators permit lower electron energies and, thus, reduce linac and undulator lengths. The first X-ray FEL facility based on in-vacuum undulators goes into operation soon (SPRING-8 XFEL). Other in-vacuum undulator based FELs are under construction (SWISS-FEL) or are planned. The in-vacuum undulators have period lengths between 18mm (SPRING-8-X-FEL) and 15mm (SWISS-FEL). In the future the period length will be pushed further into the sub-cm regime. The technical implications of these devices will be discussed: New materials such as PrFeB-magnets are employed. They show their superior characteristics at cryogenic temperatures. Geometric and magnetic tolerances will be tighter and the construction and shimming concepts have to be revised. New magnetic measurement systems are required as well. Recently, a 9mm period length 20 period prototype undulator has been built in collaboration between Ludwig-Maximilian-University Munich and Helmholtz-Zentrum Berlin. The potential and the challenges of sub-cm undulators will be illustrated based on first results from this prototype.
	Slides THOAI1 [3.344 MB]

THPA24	Development of Pr₂Fe₁₄B Cryogenic Undulator CPMU at SOLEIL	undulator, vacuum, permanent-magnet, electron	523
	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.

Paper

Title

Other Keywords

Page

THOAI1

Pushing the Limits of Short Period Permanent Magnet Undulators

undulator, vacuum, permanent-magnet, FEL

435

J. Bahrdt
HZB, Berlin, Germany

Short period undulators to be used as FEL radiators permit lower electron energies and, thus, reduce linac and undulator lengths. The first X-ray FEL facility based on in-vacuum undulators goes into operation soon (SPRING-8 XFEL). Other in-vacuum undulator based FELs are under construction (SWISS-FEL) or are planned. The in-vacuum undulators have period lengths between 18mm (SPRING-8-X-FEL) and 15mm (SWISS-FEL). In the future the period length will be pushed further into the sub-cm regime. The technical implications of these devices will be discussed: New materials such as PrFeB-magnets are employed. They show their superior characteristics at cryogenic temperatures. Geometric and magnetic tolerances will be tighter and the construction and shimming concepts have to be revised. New magnetic measurement systems are required as well. Recently, a 9mm period length 20 period prototype undulator has been built in collaboration between Ludwig-Maximilian-University Munich and Helmholtz-Zentrum Berlin. The potential and the challenges of sub-cm undulators will be illustrated based on first results from this prototype.

Slides THOAI1 [3.344 MB]

THPA24

Development of Pr₂Fe₁₄B Cryogenic Undulator CPMU at SOLEIL

undulator, vacuum, permanent-magnet, electron

523

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.