Supersonic Gasjet Based BeamProfile Monitor Amir Salehilashkajani Liverpool

Supersonic Gas-jet Based Beam-Profile Monitor Amir Salehilashkajani, Liverpool University 3 rd OMA Topical Workshop – Medical Accelerator Design and Diagnostic A. salehilashkajani@liverpool. ac. uk

Outline • Low energy accelerators and diagnostics considerations. • Transverse profile monitors. • Design and operation of a supersonic gas jet based beam profile monitor. • Design and commissioning a second setup for the hollow electron lens (HL-LHC). Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 1

Diagnostic considerations for Medical Accelerators • The growing interest in low energy physics and storage rings in the scientific community has rapidly advanced novel methods of beam diagnostics. • The following should be considered: Amir Salehilashkajani, Liverpool University Ø High energy deposition in matter. Ø Particles are very easy to bend. Ø Non-invasive diagnostics Ø Turnkey system Ø Applicable in energy range of 70 to 250 Me. V 3 rd OMA Workshop 2

Transverse profile monitors • Invasive Profile Monitors Ø Luminescent screens Ø SEM grids C. Bal et al. , Proceedings of DIPAC 2005 Lyon, France, 57 • Non-Invasive profile monitors Ø Ionisation profile monitors. Ø Beam induced fluorescent monitors. P. Forck, Lecture Notes on Beam Instrumentation and Diagnostics, JUAS 2006 Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 3

Supersonic gas-jet based beam profile monitor • Ideal beam profile monitor characteristics: Ø Non-invasive to the projectile beam and the vacuum level. Ø High intensity beams or high residual gas pressures necessary. • A supersonic gas jet based beam profile monitor was proposed to overcome these difficulties. Ø Can provide a 2 d image with one gas jet. Ø Highly directional. Ø Ionisation process well known and documented. Ø Flexible with different vacuum environments and beams. Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 4

Overview of the first setup Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 5

Commissioning a second gas-jet monitor • Smaller Interaction Chamber. • Much better vacuum and larger pumping speed. • Fixed Nozzle. • To be operated in fluorescence mode. Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 6

Beam induced fluorescence data y Gas-jet x E-beam 5 mm Fitting equation: Photon number Amir Salehilashkajani, Liverpool University Beam size Gaussian equation + linear background 1600 s integration time. 5 ke. V electron beam. 0. 70 m. A current. 3 rd OMA Workshop 7

Nitrogen Vs. Neon Nitrogen Neon • 1600 s integration time. Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 8

Overview • A beam profile monitor based on a supersonic gas jet shows enormous potential both in high and low energy regions. • Evaluate the ratio of fluorescence between Neon and Nitrogen and compare to literature. • Evaluate the density of the gas jet, both for the neon and nitrogen. • Design and commissioning a possible setup for a medical accelerator can be considered in the future. Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 9

Thanks to the BGC collaboration: Hao Zhang, J. Resta Lopez, C. Welsch (Cockcroft Institute) P. Forck, S. Udrea (GSI) M. Ady, E. Barrios Diaz, N. Chritin, T. Doddington, R. Jones, R. Kersevan, A. Mariet, P. Magagnin, S. Mazzoni, A. Rossi, G. Schneider, R. Veness, (CERN BE-BI, TE-VSC, EN-MME) Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 10

Bibliography • M. Putignano, K. -U. Kühnel, C. -D. Schröter, and C. P. Welsch, A fast, low perturbation ionization beam profile monitor based on a gas-jet curtain for the ultralow energy storage ring, Hyperfine Interact. 194, 189 (2009). • M. Putignano, Ph. D. thesis, University of Liverpool, 2012. • V. Tzoganis, et. al. , Vacuum, vol. 109, 2014. • Gero Kube, Proceedings of CAS Tuusula 2018 • P. Forck, Lecture Notes on Beam Instrumentation and Diagnostics, JUAS 2006 Amir Salehilashkajani, Liverpool University 3 rd OMA Workshop 11

Supersonic jet flow 3 H. Zhang et al. , Proceedings of 8 th HL-LHC Collabiration meeting

Data Gas-jet • Image of the electron beam as measured from the gas jet and the residual gas. E-beam • Electron beam energy =3 Ke. V. • Exposure time of the camera = 70 ms.