IPAC2012 - List of Authors (Rakowsky, G.)

Paper	Title	Page
MOPPP089	Development of a PrFeB Cryogenic Undulator at NSLS-II	762
	C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, P. He, G. Rakowsky, J. Rank, C. Rhein, T. Tanabe BNL, Upton, Long Island, New York, USA
	Recent cryogenic undulators use Praseodymium-Iron-Boron (PrFeB) magnets cooled down to 80K. The main drawn drawback of the PrFeB magnet grades developed so far are their relative low coercive field at ambient temperature, below 2 T which prevents PrFeB based cryogenic undulator from baking. Some precautions are required during the undulator assembling and shimming to ensure ultra high vacuum compatibility. However Hitachi Metal Industry (HMI) recently developed two different grades of PrFeB magnet with large coercive field but at the expense of the remanent field. The magnetization curves have been measured from 40 K up to 400 K to determine the field increase and to investigate the magnet withstanding to baking. An IVU prototype has also been baked. Magnetic measurements before and after baking are also presented.

MOPPP090	Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings	765
	O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe BNL, Upton, Long Island, New York, USA J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: US DOE, Contract No. DE-AC02-98CH10886. We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.

Paper

Title

Page

Development of a PrFeB Cryogenic Undulator at NSLS-II

762

C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, P. He, G. Rakowsky, J. Rank, C. Rhein, T. Tanabe
BNL, Upton, Long Island, New York, USA

Recent cryogenic undulators use Praseodymium-Iron-Boron (PrFeB) magnets cooled down to 80K. The main drawn drawback of the PrFeB magnet grades developed so far are their relative low coercive field at ambient temperature, below 2 T which prevents PrFeB based cryogenic undulator from baking. Some precautions are required during the undulator assembling and shimming to ensure ultra high vacuum compatibility. However Hitachi Metal Industry (HMI) recently developed two different grades of PrFeB magnet with large coercive field but at the expense of the remanent field. The magnetization curves have been measured from 40 K up to 400 K to determine the field increase and to investigate the magnet withstanding to baking. An IVU prototype has also been baked. Magnetic measurements before and after baking are also presented.

MOPPP090

Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings

765

O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe
BNL, Upton, Long Island, New York, USA
J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: US DOE, Contract No. DE-AC02-98CH10886.
We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.