HB2012 - List of Authors (Chauvin, N.)

Paper

Title

Page

Using Step-Like Nonlinear Magnets for Beam Uniformization at IFMIF Target

424

Z. Yang, J.Y. Tang
IHEP, Beijing, People's Republic of China
N. Chauvin, P.A.P. Nghiem
CEA/DSM/IRFU, France

Uniform beam distribution and minimum beam halo on target are often required in high intensity beam applications to prolong the target lifetime, ease cooling and obtain better irradiation effect. In this report, step-like nonlinear magnets instead of standard multipole magnets have been studied for the application at IFMIF. Although the preliminary results are still below the very critical requirement of spot uniformity at the IFMIF target, they are quite permissive. The method demonstrates significant advantages over the conventional combination of octupole and duodecapole on very low beam loss, better uniformity and very low cost. Further studies are needed to fully meet the IFMIF specifications.

Slides WEO3B05 [1.487 MB]

THO3A04

Beam Halo Definitions and its Consequences

511

P.A.P. Nghiem, N. Chauvin, D. Uriot
CEA/DSM/IRFU, France
W. Simeoni
CEA/IRFU, Gif-sur-Yvette, France

In high-intensity accelerators, much attention is paid to the beam halo: formation, growth interaction with the beam core, etc. Indeed, beam losses, a critical issue for those high-power accelerators, directly depend on the beam halo behaviour. But in the presence of very strong space-charge forces, the beam distribution takes very different shapes along the accelerator, often very far from any regular distributions, with very varied halo extensions. The difficulty is then to find a general definition of the halo capable of describing any distribution type. This paper proposes a definition of the beam halo, studies its consequences and compares it to the most usual ones.

Slides THO3A04 [9.030 MB]

THO3A03

Simulations and Measurements in High Intensity LEBT with Space Charge Compensation

507

N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
O. Delferrière, R. Gobin, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France
R.D. Duperrier
ESS, Lund, Sweden

Over the last years, the interest of the international scientific community for high power accelerators in the megawatt range has been increasing. One of the major challenges is to extract and transport the beam while minimizing the emittance growth in the Low Energy Beam Transport line (LEBT). Consequently, it is crucial to perform precise simulations and cautious design of LEBT. In particular, the beam dynamics calculations have to take into account not only the space charge effects but also the space charge compensation of the beam induced by ionization of the residual gas. The code SOLMAXP has been developed in CEA-Saclay to perform self-consistent calculations taking into account space charge compensation. Extensive beam dynamics simulations have been done with this code to design the IFMIF LEBT (Deuteron beam of 125 mA at 100 keV, cw). The commissioning of the IFMIF injector started a few months ago and emmittance measurements of H⁺ and D⁺ beams have been done. The first experimental results will be presented and compared to simulation.

Slides THO3A03 [3.165 MB]

Paper	Title	Page
WEO3B05	Using Step-Like Nonlinear Magnets for Beam Uniformization at IFMIF Target	424
	Z. Yang, J.Y. Tang IHEP, Beijing, People's Republic of China N. Chauvin, P.A.P. Nghiem CEA/DSM/IRFU, France
	Uniform beam distribution and minimum beam halo on target are often required in high intensity beam applications to prolong the target lifetime, ease cooling and obtain better irradiation effect. In this report, step-like nonlinear magnets instead of standard multipole magnets have been studied for the application at IFMIF. Although the preliminary results are still below the very critical requirement of spot uniformity at the IFMIF target, they are quite permissive. The method demonstrates significant advantages over the conventional combination of octupole and duodecapole on very low beam loss, better uniformity and very low cost. Further studies are needed to fully meet the IFMIF specifications.
	Slides WEO3B05 [1.487 MB]

THO3A04	Beam Halo Definitions and its Consequences	511
	P.A.P. Nghiem, N. Chauvin, D. Uriot CEA/DSM/IRFU, France W. Simeoni CEA/IRFU, Gif-sur-Yvette, France
	In high-intensity accelerators, much attention is paid to the beam halo: formation, growth interaction with the beam core, etc. Indeed, beam losses, a critical issue for those high-power accelerators, directly depend on the beam halo behaviour. But in the presence of very strong space-charge forces, the beam distribution takes very different shapes along the accelerator, often very far from any regular distributions, with very varied halo extensions. The difficulty is then to find a general definition of the halo capable of describing any distribution type. This paper proposes a definition of the beam halo, studies its consequences and compares it to the most usual ones.
	Slides THO3A04 [9.030 MB]

THO3A03	Simulations and Measurements in High Intensity LEBT with Space Charge Compensation	507
	N. Chauvin CEA/IRFU, Gif-sur-Yvette, France O. Delferrière, R. Gobin, P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France R.D. Duperrier ESS, Lund, Sweden
	Over the last years, the interest of the international scientific community for high power accelerators in the megawatt range has been increasing. One of the major challenges is to extract and transport the beam while minimizing the emittance growth in the Low Energy Beam Transport line (LEBT). Consequently, it is crucial to perform precise simulations and cautious design of LEBT. In particular, the beam dynamics calculations have to take into account not only the space charge effects but also the space charge compensation of the beam induced by ionization of the residual gas. The code SOLMAXP has been developed in CEA-Saclay to perform self-consistent calculations taking into account space charge compensation. Extensive beam dynamics simulations have been done with this code to design the IFMIF LEBT (Deuteron beam of 125 mA at 100 keV, cw). The commissioning of the IFMIF injector started a few months ago and emmittance measurements of H⁺ and D⁺ beams have been done. The first experimental results will be presented and compared to simulation.
	Slides THO3A03 [3.165 MB]