IBIC2013 - List of Keywords (space-charge)

Paper	Title	Other Keywords	Page
MOPF09	A Gas-Jet Profile Monitor for the CLIC Drive Beam	electron, ion, CLIC, focusing	224
	A. Jeff, E.B. Holzer, T. Lefèvre CERN, Geneva, Switzerland A. Jeff, V. Tzoganis, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.

MOPF22	The Effect of Space Charge Along the Tomography Section at PITZ	PITZ, emittance, transverse, simulation	255
	G. Kourkafas, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, M. Otevřel, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria
	The Photo Injector Test facility at DESY, Zeuthen site (PITZ) focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. Among various diagnostic tools installed at PITZ, the tomography module is used to reconstruct the transverse phase-space distribution of the electron beam by capturing its projections while rotating in the normalized phase space. This technique can resolve the two transverse planes simultaneously with an improved signal-to-noise ratio, allowing measurements of individual bunches within a bunch train with kicker magnets. The low emittance, high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which induce mismatches to the reconstruction procedure. This study investigates how the phase-space transformations and thus the reconstruction result are affected when considering linear and non-linear self-fields along the tomography section for the design Twiss parameters. The described analysis proposes a preliminary approach for including the effect of space charge in the tomographic reconstruction at PITZ.
	Poster MOPF22 [1.312 MB]

TUPF01	Proton Emittance Measurements in the Brookhaven AGS	emittance, AGS, IPM, injection	492
	H. Huang, R. Connolly, C.W. Dawson, D.M. Gassner, C.E. Harper, S.E. Jao, W. Meng, F. Méot, R.J. Michnoff, M.G. Minty, V. Schoefer, T. Summers, S. Tepikian, K. Yip, K. Zeno BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle and a multi-wire at injection. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. In addition, helical superconducting snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need TBT measurements near injection and beta function measurements at the location of devices used to measure the emittance. A Polarimeter target has been used as flying wire for proton emittance measurement. A new type electron collecting IPM has been installed and tested in the AGS with proton beam. The Beta functions at the IPM locations have been measured with Orbit Response Matrix (ORM) methods and with a local corrector at IPM. This paper summarizes our current understanding of AGS emittances and plans for further improvements.

TUPF16	Analysis of Measurement Errors of INR Linac Ionization Beam Cross Section Monitor	ion, linac, proton, simulation	535
	S.A. Gavrilov, A. Feschenko, P.I. Reinhardt-Nickoulin, I.V. Vasilyev RAS/INR, Moscow, Russia A. Feschenko, S.A. Gavrilov MIPT, Dolgoprudniy, Moscow Region, Russia
	Residual gas ionization beam cross section monitors (BCSM) are installed at LEBT and HEBT of INR RAS proton linac to measure cross section, profiles and position of the beam. BCSMs provide two-dimensional non-destructive real-time beam diagnostics at LINAC operation with repetition frequency from 1 to 50 Hz, pulses duration from 0.3 to 170 μs and wide range of amplitudes, particle energy 400 keV and 209 MeV. The analysis of systematic measurements errors (accuracy) because of nonuniform electrostatic fields, determined by BCSM design features, is presented. New detector model, minimizing these nonuniformities, is shown. Besides that, the analysis of statistical errors (precision) due to the method features, in particular, ions thermal motion and a beam space charge, is done. The simulation results make it possible to estimate measured cross sections size, profiles and beam positions and to draw conclusions about the reliability of BCSM results for beams with various parameters.

TUPF33	Electron Beam Diagnostics Using Radiation from a Free Electron Laser	electron, radiation, plasma, FEL	593
	M. Arbel H.I.T., Holon, Israel A. Eichenbaum Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
	In most devices based on a high energy electron beam, which used for electromagnetic radiation production, great efforts are focused on the electron beam quality improvement. This is the case in a Free-Electron Laser (FEL) where electron beam with a low normalized emittance is required. Thus, diagnostic tools are required to investigate e-beam properties, such as beam emittance, longitudinal space charge, energy spread and velocity spread. In this paper we present analysis of radiation measurements obtained from a pre-bunched e-beam FEL. The measurements were made for a wide range of frequencies and for beam currents from low currents to high currents, where space charge effects can not neglected. We apply a frequency domain formulation to analyze the measured radiation. The spectral signature of the radiation emission obtained from a pre-bunched e-beam can provide vital information on e-beam properties. We show that a rigorous analysis of the measured radiation, allows characterization of the e-beam parameters. This analysis can provide some insights to the development of e-beam accelerators and radiation sources devices and to help physicists interpreting radiated signals.

WEPF22	Non Invasive Optical Synchrotron Radiation Monitor Using a Mini-Chicane	emittance, electron, radiation, diagnostics	860
	R.B. Fiorito, R.A. Kishek, A.G. Shkvarunets UMD, College Park, Maryland, USA D. Castronovo, M. Cornacchia, S. Di Mitri, M. Veronese Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy C. Tschalär MIT, Middleton, Massachusetts, USA
	Funding: Office of Naval Research and DOD Joint Technology Office We are developing a design for a minimally perturbing mini-chicane which utilizes the optical synchrotron radiation (OSR) generated from magnetic bends to measure the rms emittance and other optical parameters of the beam. The beam is first externally focused at the first bend and the OSR generated there is used to image the beam. Subsequently, any pair of bends produces interferences (OSRI) whose visibility can used to determine the beam divergence. The properties of different configuration of bends in the chicane have been analyzed to provide an optimum diagnostic design for a given set of beam parameters which: 1) provides a sufficient number of OSRI fringes to allow a measurement of the beam divergence; 2) minimizes the competing effect of energy spread on the fringe visibility; 3) minimizes the effect of coherent synchrotron radiation and space charge on the beam emittance; and 4) minimizes the effect of compression on the bunch length, as the beam passes through the chicane. Diagnostic designs have been produced for 100-300 MeV beams with a normalized rms emittance of about 1 micron for application to Fermi@Elettra and similar high brightness free electron lasers.
	Poster WEPF22 [0.642 MB]

Paper

Title

Other Keywords

Page

MOPF09

A Gas-Jet Profile Monitor for the CLIC Drive Beam

electron, ion, CLIC, focusing

224

A. Jeff, E.B. Holzer, T. Lefèvre
CERN, Geneva, Switzerland
A. Jeff, V. Tzoganis, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 10¹⁵ electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.

MOPF22

The Effect of Space Charge Along the Tomography Section at PITZ

PITZ, emittance, transverse, simulation

255

G. Kourkafas, M. Khojoyan, M. Krasilnikov, D. Malyutin, B. Marchetti, M. Otevřel, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria

The Photo Injector Test facility at DESY, Zeuthen site (PITZ) focuses on testing, characterizing and optimizing high brightness electron sources for free electron lasers. Among various diagnostic tools installed at PITZ, the tomography module is used to reconstruct the transverse phase-space distribution of the electron beam by capturing its projections while rotating in the normalized phase space. This technique can resolve the two transverse planes simultaneously with an improved signal-to-noise ratio, allowing measurements of individual bunches within a bunch train with kicker magnets. The low emittance, high charge density and moderate energy of the electron bunch at PITZ contribute to significant space-charge forces which induce mismatches to the reconstruction procedure. This study investigates how the phase-space transformations and thus the reconstruction result are affected when considering linear and non-linear self-fields along the tomography section for the design Twiss parameters. The described analysis proposes a preliminary approach for including the effect of space charge in the tomographic reconstruction at PITZ.

Poster MOPF22 [1.312 MB]

TUPF01

Proton Emittance Measurements in the Brookhaven AGS

emittance, AGS, IPM, injection

492

H. Huang, R. Connolly, C.W. Dawson, D.M. Gassner, C.E. Harper, S.E. Jao, W. Meng, F. Méot, R.J. Michnoff, M.G. Minty, V. Schoefer, T. Summers, S. Tepikian, K. Yip, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
High luminosity and high polarization in RHIC require good control and measurement of emittance in its injector, the Brookhaven AGS. In the past, the AGS emittance has been measured by using an ion collecting IPM during the whole cycle and a multi-wire at injection. The beam profiles from this IPM are distorted by space charge forces at higher energy, which makes the emittance determination very hard. In addition, helical superconducting snake magnets and near integer vertical tune for polarized proton operation distort the lattice in the AGS and introduce large beta beating. For more precise measurements of the emittance, we need TBT measurements near injection and beta function measurements at the location of devices used to measure the emittance. A Polarimeter target has been used as flying wire for proton emittance measurement. A new type electron collecting IPM has been installed and tested in the AGS with proton beam. The Beta functions at the IPM locations have been measured with Orbit Response Matrix (ORM) methods and with a local corrector at IPM. This paper summarizes our current understanding of AGS emittances and plans for further improvements.

TUPF16

Analysis of Measurement Errors of INR Linac Ionization Beam Cross Section Monitor

ion, linac, proton, simulation

535

S.A. Gavrilov, A. Feschenko, P.I. Reinhardt-Nickoulin, I.V. Vasilyev
RAS/INR, Moscow, Russia
A. Feschenko, S.A. Gavrilov
MIPT, Dolgoprudniy, Moscow Region, Russia

Residual gas ionization beam cross section monitors (BCSM) are installed at LEBT and HEBT of INR RAS proton linac to measure cross section, profiles and position of the beam. BCSMs provide two-dimensional non-destructive real-time beam diagnostics at LINAC operation with repetition frequency from 1 to 50 Hz, pulses duration from 0.3 to 170 μs and wide range of amplitudes, particle energy 400 keV and 209 MeV. The analysis of systematic measurements errors (accuracy) because of nonuniform electrostatic fields, determined by BCSM design features, is presented. New detector model, minimizing these nonuniformities, is shown. Besides that, the analysis of statistical errors (precision) due to the method features, in particular, ions thermal motion and a beam space charge, is done. The simulation results make it possible to estimate measured cross sections size, profiles and beam positions and to draw conclusions about the reliability of BCSM results for beams with various parameters.

TUPF33

Electron Beam Diagnostics Using Radiation from a Free Electron Laser

electron, radiation, plasma, FEL

593

M. Arbel
H.I.T., Holon, Israel
A. Eichenbaum
Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel

In most devices based on a high energy electron beam, which used for electromagnetic radiation production, great efforts are focused on the electron beam quality improvement. This is the case in a Free-Electron Laser (FEL) where electron beam with a low normalized emittance is required. Thus, diagnostic tools are required to investigate e-beam properties, such as beam emittance, longitudinal space charge, energy spread and velocity spread. In this paper we present analysis of radiation measurements obtained from a pre-bunched e-beam FEL. The measurements were made for a wide range of frequencies and for beam currents from low currents to high currents, where space charge effects can not neglected. We apply a frequency domain formulation to analyze the measured radiation. The spectral signature of the radiation emission obtained from a pre-bunched e-beam can provide vital information on e-beam properties. We show that a rigorous analysis of the measured radiation, allows characterization of the e-beam parameters. This analysis can provide some insights to the development of e-beam accelerators and radiation sources devices and to help physicists interpreting radiated signals.

WEPF22

Non Invasive Optical Synchrotron Radiation Monitor Using a Mini-Chicane

emittance, electron, radiation, diagnostics

860

R.B. Fiorito, R.A. Kishek, A.G. Shkvarunets
UMD, College Park, Maryland, USA
D. Castronovo, M. Cornacchia, S. Di Mitri, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
C. Tschalär
MIT, Middleton, Massachusetts, USA

Funding: Office of Naval Research and DOD Joint Technology Office
We are developing a design for a minimally perturbing mini-chicane which utilizes the optical synchrotron radiation (OSR) generated from magnetic bends to measure the rms emittance and other optical parameters of the beam. The beam is first externally focused at the first bend and the OSR generated there is used to image the beam. Subsequently, any pair of bends produces interferences (OSRI) whose visibility can used to determine the beam divergence. The properties of different configuration of bends in the chicane have been analyzed to provide an optimum diagnostic design for a given set of beam parameters which: 1) provides a sufficient number of OSRI fringes to allow a measurement of the beam divergence; 2) minimizes the competing effect of energy spread on the fringe visibility; 3) minimizes the effect of coherent synchrotron radiation and space charge on the beam emittance; and 4) minimizes the effect of compression on the bunch length, as the beam passes through the chicane. Diagnostic designs have been produced for 100-300 MeV beams with a normalized rms emittance of about 1 micron for application to Fermi@Elettra and similar high brightness free electron lasers.

Poster WEPF22 [0.642 MB]