DIPAC2011 - List of Authors (Barth, W.A.)

Paper

Title

Page

Beam Emittance Studies at the Heavy Ion Linac UNILAC

245

P. Gerhard, W.A. Barth, L.A. Dahl, L. Groening, H. Vormann
GSI, Darmstadt, Germany

New accelerating structures for the UNILAC at GSI were commissioned in the last two years [1, 2], and major machine upgrades in order to meet the requirements for FAIR are in preparation [3, 4]. Beam emittance is one of the key beam parameters that are essential for any beam dynamics calculation, for the design of new accelerators as well as verification or investigation of existing machines. Its measurement is intricate and often time consuming. Extensive emittance measurements went along with the commissionings and were conducted to provide a reliable basis for beam dynamics simulations. In addition to the 10 permanent transverse emittance measurement devices installed all over the UNILAC, two "mobile" devices had been built and mounted at four different sites in the UNILAC. This work shows the standard slid-grid device used for transverse beam emittance measurements and gives an overview of the activities and results. The following topics will be presented with respect to design studies and simulations: Emittance growth of high current ion beams along the UNILAC, stripping, and resonance effects.
[1] H. Vormann et al., LINAC10, MOP040
[2] P. Gerhard et al., IPAC10, MOPD028
[3] W. Barth et al., PAC09, FR5REP059
[4] S. Mickat et al., LINAC10, MOP042

Poster MOPD85 [10.077 MB]

TUPD05

Diagnostic Scheme for the HITRAP Decelerator

311

G. Vorobjev, C.A. Andre, W.A. Barth, E. Berdermann, M.I. Ciobanu, G. Clemente, L.A. Dahl, P. Forck, P. Gerhard, R. Haseitl, F. Herfurth, M. Kaiser, W. Kaufmann, H.J. Kluge, N. Kotovski, C. Kozhuharov, M.T. Maier, W. Quint, A. Reiter, A. Sokolov, T. Stöhlker
GSI, Darmstadt, Germany
O.K. Kester, J. Pfister, U. Ratzinger, A. Schempp
IAP, Frankfurt am Main, Germany

The HITRAP linear decelerator currently being set up at GSI will provide slow, few keV/u highly charged ions for atomic physics experiments. The expected beam intensity is up to 10⁵ ions per shot. To optimize phase and amplitude of the RF systems intensity, bunch length and kinetic energy of the particles need to be monitored. The bunch length that we need to fit is about 2 ns, which is typically measured by capacitive pickups. However, they do not work for the low beam intensities that we face. We investigated the bunch length with a fast CVD diamond detector working in single particle counting mode. Averaging over 8 shots yields a clear, regular picture of the bunched beam. Energy measurements by capacitive pickups are limited by the presence of intense primary and partially decelerated beam and hence make tuning of the IH-structure impossible. The energy of the decelerated fraction of the beam behind the first deceleration cavity was determined to about 10 % accuracy with a permanent dipole magnet combined with a MCP. Better detector calibration should help reaching the required 1%. Design of the detectors as well as the results of the measurements will be presented.

Paper	Title	Page
MOPD85	Beam Emittance Studies at the Heavy Ion Linac UNILAC	245
	P. Gerhard, W.A. Barth, L.A. Dahl, L. Groening, H. Vormann GSI, Darmstadt, Germany
	New accelerating structures for the UNILAC at GSI were commissioned in the last two years [1, 2], and major machine upgrades in order to meet the requirements for FAIR are in preparation [3, 4]. Beam emittance is one of the key beam parameters that are essential for any beam dynamics calculation, for the design of new accelerators as well as verification or investigation of existing machines. Its measurement is intricate and often time consuming. Extensive emittance measurements went along with the commissionings and were conducted to provide a reliable basis for beam dynamics simulations. In addition to the 10 permanent transverse emittance measurement devices installed all over the UNILAC, two "mobile" devices had been built and mounted at four different sites in the UNILAC. This work shows the standard slid-grid device used for transverse beam emittance measurements and gives an overview of the activities and results. The following topics will be presented with respect to design studies and simulations: Emittance growth of high current ion beams along the UNILAC, stripping, and resonance effects. [1] H. Vormann et al., LINAC10, MOP040 [2] P. Gerhard et al., IPAC10, MOPD028 [3] W. Barth et al., PAC09, FR5REP059 [4] S. Mickat et al., LINAC10, MOP042
	Poster MOPD85 [10.077 MB]

TUPD05	Diagnostic Scheme for the HITRAP Decelerator	311
	G. Vorobjev, C.A. Andre, W.A. Barth, E. Berdermann, M.I. Ciobanu, G. Clemente, L.A. Dahl, P. Forck, P. Gerhard, R. Haseitl, F. Herfurth, M. Kaiser, W. Kaufmann, H.J. Kluge, N. Kotovski, C. Kozhuharov, M.T. Maier, W. Quint, A. Reiter, A. Sokolov, T. Stöhlker GSI, Darmstadt, Germany O.K. Kester, J. Pfister, U. Ratzinger, A. Schempp IAP, Frankfurt am Main, Germany
	The HITRAP linear decelerator currently being set up at GSI will provide slow, few keV/u highly charged ions for atomic physics experiments. The expected beam intensity is up to 10⁵ ions per shot. To optimize phase and amplitude of the RF systems intensity, bunch length and kinetic energy of the particles need to be monitored. The bunch length that we need to fit is about 2 ns, which is typically measured by capacitive pickups. However, they do not work for the low beam intensities that we face. We investigated the bunch length with a fast CVD diamond detector working in single particle counting mode. Averaging over 8 shots yields a clear, regular picture of the bunched beam. Energy measurements by capacitive pickups are limited by the presence of intense primary and partially decelerated beam and hence make tuning of the IH-structure impossible. The energy of the decelerated fraction of the beam behind the first deceleration cavity was determined to about 10 % accuracy with a permanent dipole magnet combined with a MCP. Better detector calibration should help reaching the required 1%. Design of the detectors as well as the results of the measurements will be presented.