HB2012 - List of Authors (Schwickert, M.)

Paper

Title

Page

Optical Transition Radiation for Non-relativistic Ion Beams

580

B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert, R. Singh
GSI, Darmstadt, Germany
A.H. Lumpkin
Fermilab, Batavia, USA

In this contribution, recent results of Optical Transition Radiation (OTR) measurements with a non-relativistic heavy-ion beam will be presented. This feasibility study was prompted by previous measurements [1] and the theoretical estimation of expected signal strengths for the GSI linear accelerator UNILAC. For this experiment, an 11.4 MeV/u Uranium beam was chosen to investigate OTR signal from several target materials and to evaluate the working regime for the used experimental setup. The OTR light was either observed directly with an Image Intensified CCD camera (ICCD) or indirectly via a spectrometer for wavelength resolved data. A moveable stripping foil allowed measurements with two different ion charge states. The theoretical q2 dependency of the OTR process predicts a six-fold increase in light yield which was confirmed experimentally. Obtained OTR beam profiles were compered to SEM-Grid data. Moreover, ICCD gating feature, as well as the emitted light spectrum ruled out contribution of any background sources with longer emission time constant e.g. blackbody radiation.
[1] C. Bal et al., "OTR from Non-relativistic Electrons", Proceedings of DIPAC03, PM04, Mainz Germany.

Slides THO3C01 [1.905 MB]

THO3C02

Momentum Spread Determination of Linac Beams Using Incoherent Components of the Bunch Signals

583

P. Kowina, P. Forck, M. Schwickert
GSI, Darmstadt, Germany
F. Caspers
CERN, Geneva, Switzerland

Measurements of the momentum spread of the beam particles are of great importance when optimizing linac settings for high current operation with controlled longitudinal phase space occupation. A new method of momentum spread determination was tested at the GSI heavy ion linear accelerator UNILAC. The method is based on an analysis of incoherent components of the bunch signal. A significant enhancement of the signal-to-noise ratio was achieved by means of a resonant pick-up of pill-box shape. Spectra were analyzed on the 36th harmonics of the linac rf-frequency, i.e. at 1.3 GHz. Thus, the contribution of coherent components in the frequency spectrum of the bunched beam, e.g. due to common mode, was significantly damped. Fast digital processing and gating synchronized to the bunch train allowed for a drastic reduction of the measurement time and, additionally, suppressed noise signals in the frequency spectrum. This contribution describes the measurement setup and discusses first results obtained with heavy ion beams.

Slides THO3C02 [2.131 MB]

Paper	Title	Page
THO3C01	Optical Transition Radiation for Non-relativistic Ion Beams	580
	B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert, R. Singh GSI, Darmstadt, Germany A.H. Lumpkin Fermilab, Batavia, USA
	In this contribution, recent results of Optical Transition Radiation (OTR) measurements with a non-relativistic heavy-ion beam will be presented. This feasibility study was prompted by previous measurements [1] and the theoretical estimation of expected signal strengths for the GSI linear accelerator UNILAC. For this experiment, an 11.4 MeV/u Uranium beam was chosen to investigate OTR signal from several target materials and to evaluate the working regime for the used experimental setup. The OTR light was either observed directly with an Image Intensified CCD camera (ICCD) or indirectly via a spectrometer for wavelength resolved data. A moveable stripping foil allowed measurements with two different ion charge states. The theoretical q2 dependency of the OTR process predicts a six-fold increase in light yield which was confirmed experimentally. Obtained OTR beam profiles were compered to SEM-Grid data. Moreover, ICCD gating feature, as well as the emitted light spectrum ruled out contribution of any background sources with longer emission time constant e.g. blackbody radiation. [1] C. Bal et al., "OTR from Non-relativistic Electrons", Proceedings of DIPAC03, PM04, Mainz Germany.
	Slides THO3C01 [1.905 MB]

THO3C02	Momentum Spread Determination of Linac Beams Using Incoherent Components of the Bunch Signals	583
	P. Kowina, P. Forck, M. Schwickert GSI, Darmstadt, Germany F. Caspers CERN, Geneva, Switzerland
	Measurements of the momentum spread of the beam particles are of great importance when optimizing linac settings for high current operation with controlled longitudinal phase space occupation. A new method of momentum spread determination was tested at the GSI heavy ion linear accelerator UNILAC. The method is based on an analysis of incoherent components of the bunch signal. A significant enhancement of the signal-to-noise ratio was achieved by means of a resonant pick-up of pill-box shape. Spectra were analyzed on the 36th harmonics of the linac rf-frequency, i.e. at 1.3 GHz. Thus, the contribution of coherent components in the frequency spectrum of the bunched beam, e.g. due to common mode, was significantly damped. Fast digital processing and gating synchronized to the bunch train allowed for a drastic reduction of the measurement time and, additionally, suppressed noise signals in the frequency spectrum. This contribution describes the measurement setup and discusses first results obtained with heavy ion beams.
	Slides THO3C02 [2.131 MB]