DIPAC2011 - List of Authors (Forck, P.)

Paper

Title

Page

Beam Diagnostic Layout for SIS100 at FAIR

41

M. Schwickert, P. Forck, T. Hoffmann, P. Kowina, H. Reeg
GSI, Darmstadt, Germany

The SIS100 heavy ion synchrotron will be the central machine of the FAIR (Facility for Antiprotons and Ions Research) project currently designed at GSI. The unique features of SIS100, like e.g. the acceleration of high intensity beams of 2.5·10¹³ protons and 5·10¹¹ Uranium ions near the space charge limit, the anticipated large tune spread, extreme UHV conditions of the cryogenic system for superconducting magnets and fast ramp rates of 4 T/s, make challenging demands on the beam diagnostic components. This contribution describes the conceptual design for SIS100 beam diagnostics and reports on the present status of prototype studies. Exemplarily the progress concerning beam position monitors, beam current transformers and beam-loss monitors is presented.

MOPD16

Advanced Digital Signal Processing for Effective Beam Position Monitoring

74

D.A. Liakin
ITEP, Moscow, Russia
P. Forck, K. Lang, R. Singh
GSI, Darmstadt, Germany

A latest experience in digital signal processing of BPM data obtained in synchrotrons of ITEP and GSI is discussed. The data in ITEP was collected by BPM processor prototype while the SIS18 in GSI uses a renovated digital system. Due to different concept of BPM architectures on those facilities it is possible to compare algorithms oriented to certain hardware. Several algorithms of position detection are compared to each other. Performances of ‘collective’ and partly distributed algorithms are estimated. Data reduction methods and visualization solutions are considered. Finally low- and wideband data evaluation for longitudinal phase space is presented.

Poster MOPD16 [13.416 MB]

MOPD53

Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI

170

P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne
GSI, Darmstadt, Germany
W. Ensinger, K. Renuka
TU Darmstadt, Darmstadt, Germany

Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026
Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.

Poster MOPD53 [1.897 MB]

MOPD57

Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations

179

E. Gütlich, P. Forck, B. Walasek-Höhne
GSI, Darmstadt, Germany
W. Ensinger
TU Darmstadt, Darmstadt, Germany

Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al₂O₃ with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al₂O₃ this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators.

MOPD60

Beam Induced Fluorescence (BIF) Monitors as a Standard Operating Tool

185

C.A. Andre, F. Becker, H. Bräuning, P. Forck, R. Haseitl, R. Lonsing, B. Walasek-Höhne
GSI, Darmstadt, Germany

For high current operation at the GSI Heavy Ion UNILAC non intercepting methods for transverse beam profile determination are required. The Beam Induced Fluorescence (BIF) Monitor, an optical measurement device based on the observation of fluorescent light emitted by excited gas molecules was brought to routine operation. Detailed investigations were conducted for various beam parameters to improve the electronics and the optical setup. Up to now, four BIF monitor stations (for detection of both, horizontal and vertical beam profiles) were installed at UNILAC and two additional setups are planned. This contribution reports on first upgrades of the BIF monitors with a Siemens PLC for FESA-based slow controls and hardware protection procedures. The versatile control and display software ProfileView is presented as an easy-to-use and stable beam diagnostic tool for the GSI operating team.

Poster MOPD60 [3.060 MB]

MOPD69

Tune Measurements with High Intensity Beams at SIS-18

206

R. Singh, P. Forck, W. Kaufmann, P. Kowina
GSI, Darmstadt, Germany
R. Singh
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork), Project Number ITN-2008-215080
To achieve high current operation close to the space charge limit in a synchrotron, a precise tune measurement during a full accelerating cycle is required. A tune measurement system that was recently commissioned at GSI synchrotron SIS-18 allows for online evaluation of the actual tune. This system consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations of the beam. The BPM signals thus induced are digitized by fast ADCs at 125 MSa/s and then the post processing electronics integrates the data bunch by bunch to obtain one position value per bunch. Subsequently base band tune is determined by Fourier transformation of the position data. The tune variation during acceleration for various beam conditions was measured using this system and is discussed. A detailed investigation of the incoherent tune shift was conducted with Uranium ion beams at the injection energy of 11.6 MeV/u. The results show the influence of beam current on the tune spectrum. In addition, the effects of the measurement method on the beam emittance and beam losses are discussed.

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.

TUPD24

Design Status of Beam Position Monitors for the FAIR Proton Linac

356

C.S. Simon, F. Senée
CEA/DSM/IRFU, France
G. Clemente, P. Forck, W. Kaufmann, P. Kowina
GSI, Darmstadt, Germany

Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

TUPD51

Ionization Profile Monitors - IPM @ GSI

419

T. Giacomini, P. Forck
GSI, Darmstadt, Germany
J.G. De Villiers
iThemba LABS, Somerset West, South Africa
J. Dietrich
FZJ, Jülich, Germany
D.A. Liakin
ITEP, Moscow, Russia

The Ionization Profile Monitor in the SIS18 is frequently used for machine development. The permanent availability and the elaborated software user interface make it easy and comfortable to use. Additional to the beam profile data the device records the data of synchrotron dc current, dipole ramp and accelerating rf properties. The trend curves of these data are shown correlated to the beam profile evolution for a full synchrotron cycle from injection to extraction with 100 profiles/s. The reliable function is based on the optimized in-vacuum hardware design, like the stable high voltage connections, the electric field box with very uniform field distribution and the uv-light based calibration system. The permanent availability is based on the convenient software interface using the Qt library. A new IPM generation was recently commissioned in the experimental storage ring ESR at GSI and one in the COSY ring at FZ-Jülich. These monitors are enhancements of the SIS18 multiwire IPM but equipped with an especially developed large area 50x100 mm² optical particle detector of rectangular shape that is readout by a digital camera through a viewport.

WEOA03

Detailed Experimental Characterization of an Ionization Profile Monitor

547

J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou
CEA, Gif-sur-Yvette, France
F. Becker, P. Forck, B. Walasek-Höhne
GSI, Darmstadt, Germany
J. Marroncle
CEA/DSM/IRFU, France

Funding: Marie Curie Fellowship by the EU
In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.

Slides WEOA03 [1.964 MB]

Paper	Title	Page
MOPD05	Beam Diagnostic Layout for SIS100 at FAIR	41
	M. Schwickert, P. Forck, T. Hoffmann, P. Kowina, H. Reeg GSI, Darmstadt, Germany
	The SIS100 heavy ion synchrotron will be the central machine of the FAIR (Facility for Antiprotons and Ions Research) project currently designed at GSI. The unique features of SIS100, like e.g. the acceleration of high intensity beams of 2.5·10¹³ protons and 5·10¹¹ Uranium ions near the space charge limit, the anticipated large tune spread, extreme UHV conditions of the cryogenic system for superconducting magnets and fast ramp rates of 4 T/s, make challenging demands on the beam diagnostic components. This contribution describes the conceptual design for SIS100 beam diagnostics and reports on the present status of prototype studies. Exemplarily the progress concerning beam position monitors, beam current transformers and beam-loss monitors is presented.

MOPD16	Advanced Digital Signal Processing for Effective Beam Position Monitoring	74
	D.A. Liakin ITEP, Moscow, Russia P. Forck, K. Lang, R. Singh GSI, Darmstadt, Germany
	A latest experience in digital signal processing of BPM data obtained in synchrotrons of ITEP and GSI is discussed. The data in ITEP was collected by BPM processor prototype while the SIS18 in GSI uses a renovated digital system. Due to different concept of BPM architectures on those facilities it is possible to compare algorithms oriented to certain hardware. Several algorithms of position detection are compared to each other. Performances of ‘collective’ and partly distributed algorithms are estimated. Data reduction methods and visualization solutions are considered. Finally low- and wideband data evaluation for longitudinal phase space is presented.
	Poster MOPD16 [13.416 MB]

MOPD53	Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI	170
	P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne GSI, Darmstadt, Germany W. Ensinger, K. Renuka TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026 Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.
	Poster MOPD53 [1.897 MB]

MOPD57	Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations	179
	E. Gütlich, P. Forck, B. Walasek-Höhne GSI, Darmstadt, Germany W. Ensinger TU Darmstadt, Darmstadt, Germany
	Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al₂O₃ with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al₂O₃ this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators.

MOPD60	Beam Induced Fluorescence (BIF) Monitors as a Standard Operating Tool	185
	C.A. Andre, F. Becker, H. Bräuning, P. Forck, R. Haseitl, R. Lonsing, B. Walasek-Höhne GSI, Darmstadt, Germany
	For high current operation at the GSI Heavy Ion UNILAC non intercepting methods for transverse beam profile determination are required. The Beam Induced Fluorescence (BIF) Monitor, an optical measurement device based on the observation of fluorescent light emitted by excited gas molecules was brought to routine operation. Detailed investigations were conducted for various beam parameters to improve the electronics and the optical setup. Up to now, four BIF monitor stations (for detection of both, horizontal and vertical beam profiles) were installed at UNILAC and two additional setups are planned. This contribution reports on first upgrades of the BIF monitors with a Siemens PLC for FESA-based slow controls and hardware protection procedures. The versatile control and display software ProfileView is presented as an easy-to-use and stable beam diagnostic tool for the GSI operating team.
	Poster MOPD60 [3.060 MB]

MOPD69	Tune Measurements with High Intensity Beams at SIS-18	206
	R. Singh, P. Forck, W. Kaufmann, P. Kowina GSI, Darmstadt, Germany R. Singh TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork), Project Number ITN-2008-215080 To achieve high current operation close to the space charge limit in a synchrotron, a precise tune measurement during a full accelerating cycle is required. A tune measurement system that was recently commissioned at GSI synchrotron SIS-18 allows for online evaluation of the actual tune. This system consists of three distinct parts; an exciter which provides power to excite coherent betatron oscillations of the beam. The BPM signals thus induced are digitized by fast ADCs at 125 MSa/s and then the post processing electronics integrates the data bunch by bunch to obtain one position value per bunch. Subsequently base band tune is determined by Fourier transformation of the position data. The tune variation during acceleration for various beam conditions was measured using this system and is discussed. A detailed investigation of the incoherent tune shift was conducted with Uranium ion beams at the injection energy of 11.6 MeV/u. The results show the influence of beam current on the tune spectrum. In addition, the effects of the measurement method on the beam emittance and beam losses are discussed.

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.

TUPD24	Design Status of Beam Position Monitors for the FAIR Proton Linac	356
	C.S. Simon, F. Senée CEA/DSM/IRFU, France G. Clemente, P. Forck, W. Kaufmann, P. Kowina GSI, Darmstadt, Germany
	Beam Position Monitors (BPM) based on capacitive buttons are designed for the FAIR Proton-LINAC, constructed as an extension of the existing GSI facility. This LINAC is aiming to produce a maximum design current of 70 mA at the 70 MeV energy with an accelerating frequency of 325 MHz. At 14 locations, the BPMs will measure the transverse beam position, the relative beam current and the mean beam energy by time-of-flight method. Depending of the location, the BPM design has to be optimized, taking into account an energy range from 3 MeV to 70 MeV, a short insertion and a beam pipe aperture changes from 30 mm to 50 mm. Some of BPMs will be mounted very close to the CH cavities and special care must be taken to suppress the pickup of the strong rf-field from that cavities. In this contribution, the status of the BPM design will be presented.

TUPD51	Ionization Profile Monitors - IPM @ GSI	419
	T. Giacomini, P. Forck GSI, Darmstadt, Germany J.G. De Villiers iThemba LABS, Somerset West, South Africa J. Dietrich FZJ, Jülich, Germany D.A. Liakin ITEP, Moscow, Russia
	The Ionization Profile Monitor in the SIS18 is frequently used for machine development. The permanent availability and the elaborated software user interface make it easy and comfortable to use. Additional to the beam profile data the device records the data of synchrotron dc current, dipole ramp and accelerating rf properties. The trend curves of these data are shown correlated to the beam profile evolution for a full synchrotron cycle from injection to extraction with 100 profiles/s. The reliable function is based on the optimized in-vacuum hardware design, like the stable high voltage connections, the electric field box with very uniform field distribution and the uv-light based calibration system. The permanent availability is based on the convenient software interface using the Qt library. A new IPM generation was recently commissioned in the experimental storage ring ESR at GSI and one in the COSY ring at FZ-Jülich. These monitors are enhancements of the SIS18 multiwire IPM but equipped with an especially developed large area 50x100 mm² optical particle detector of rectangular shape that is readout by a digital camera through a viewport.

WEOA03	Detailed Experimental Characterization of an Ionization Profile Monitor	547
	J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou CEA, Gif-sur-Yvette, France F. Becker, P. Forck, B. Walasek-Höhne GSI, Darmstadt, Germany J. Marroncle CEA/DSM/IRFU, France
	Funding: Marie Curie Fellowship by the EU In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.
	Slides WEOA03 [1.964 MB]