# 17th International Conference on Ion Sources

15-20 October 2017
CERN
Europe/Zurich timezone

## Integrated Modeling of the Beam Formation and Extraction in the Linac4 Hydrogen Negative Ion Source

18 Oct 2017, 16:30
2h 30m
CERN

#### CERN

Centre international de Conférence Genève (CICG). http://www.cicg.ch/
Poster presentation Beam extraction, transport, and diagnostics

### Speaker

Mr Shu Nishioka (Faculty of Science and Technology, Keio University)

### Description

Linac4 H$^-$ ion source is required to deliver 50 mA of H$^-$ ions within a transverse rms emittance of 0.25π mm∙mrad[1, 2]. In order to meet these requirements, it is indispensable to clarify the H$^-$ ion extraction and beam formation process in the vicinity of the beam extraction hole i.e. extraction region in the H$^-$ ion source. In the previous works, the extraction region in the Linac4 H$^-$ ion source has been modeled by the 2D Particle in Cell (PIC) [3] method and 3D PIC method [4]. In the Ref. [4], the extracted H$^-$ ion beam current and co-extracted electron current by the 3D PIC simulation has been compared with the experiments. However, the beam emittance calculated by the simulation model has not been directly compared with the experiments.

In order to compare the beam emittance with the experiments, we are now developing the integrated model of the source plasma, extraction region and acceleration region. As for the source plasma, the NINJA [5], which is 2D Electro-Magnetic-PIC (EM-PIC) code for the RF inductively coupled plasma has been applied. In the extraction region, 3D KEIO-Beam Formation and eXtraction (BFX) code has been applied to calculate the plasma meniscus and H$^-$ ion beam formation process. Finally, the IBSIMU and the TRAVEL-3D have been applied in the beam transport in the acceleration region to obtain the beam emittance.

We have performed the case of the positive ion extraction for the validation of the integrated model. It has been shown that the extracted positive ion current by the integrated model reasonably agrees with the experiment. In the presentation, we will show the case of the negative ion extraction, and the H$^-$ beam emittance and extracted beam current will be compared with the experiments.

References

[1] J. Lettry et. al., AIP Conf. Proc. 1655, 030005 (2015).

[2] J. Lettry et. al., Rev. Sci. Instrum. 87, 02B139 (2016).

[3] S. Abe, et. al., AIP Conf. Proc. in press.

[4] S. Mochalskyy, et. al., New J. Phys. 18, 085011 (2016)

[5] S. Nishioka, et. al., J. Appl. Phys. 119, 023302 (2016).

[6]. S. Mattei, et. al., J. Comp. Phys. to be published.

[7]. A. Perrin, J.F. Amand, Travel v4.06, user manual,2003.

[8]. T. Kalvas, Ion Beam Simulator distribution website, http://users.jyu.fi/~tvkalvas/ibsimu/, 5 June 2017.

### Primary author

Mr Shu Nishioka (Faculty of Science and Technology, Keio University)

### Co-authors

Stefano Mattei (Ecole Polytechnique Federale de Lausanne ) Jean-Baptiste Lallement (CERN) Taneli Kalvas (Department of Physics-University of Jyvaskyla) Kenji Miyamoto (Naruto University of Education) Prof. Akiyoshi Hatayama (Faculty of Science and Technology, Keio University) Jacques Lettry (CERN)

### Presentation materials

 poster_ver1.0SN.pdf poster_ver1.0SN.ppt