60 GHz ECR Ion Source for RIB production T. Lamy, L. Latrasse, T. Thuillier, C. Fourel, J. Giraud Laboratoire de Physique Subatomique et de Cosmologie CNRS/IN2P3, U. Joseph Fourier, INP Grenoble, France F. Debray, C. Trophime, P. Sala, J. Dumas Laboratoire National des Champs Magnétiques Intenses CNRS, INSA Toulouse, U. Paul Sabatier - Toulouse, U. Joseph Fourier, Grenoble, France I. Izotov, A. V. Sidorov, V. A. Skalyga, V. G. Zorin Institute of Applied Physics Russian Academy of Science Nizhny Novgorod, Russia

Summary The initial idea : A dream ? Towards reality The reality A possible future ?

60 GHz ECR source for RIB production : where ?

The initial idea : A dream ? Moriond meeting les Arcs 2003: Pascal Sortais LPSC-Grenoble 60 - 90 GHz « ECR Duoplasmatron » for pre-bunching of gaseous RIB 2.0 – 3.0 T pulsed coils or SC coils ECR: 1T@28 GHz Very high density magnetized plasma ne ~ 1014 cm-3 Very small plasma chamber F ~ 20 mm / L ~ 50 mm Target 1-3 mm 100 KV extraction Rapid pulsed valve 100 µs 20 mA 1012 to 1013 ions per bunch with high efficiency 60-90 GHz / 10-100 KW 10 –200 µs /  = 6-3 mm optical axial coupling

Magnetic field configuration Towards reality Plasma Density Very high density magnetized plasma ne ~ 1014 cm-3 ECR Cut off density (nc) c.e.(rad/s) = 2fc.e. (Hz) = p = (nce2/0 me)1/2 nc = (2fc.e)2 0 me /e2 2.45 GHz (Becr = 874 Gauss) ne = ni = 7.4 1010 cm-3 56 GHz (Becr = 2 T) ne = ni = 3.88 1013 cm-3 So 60 GHz (Becr = 2.14 T) ne = ni = 4.46 1013 cm-3 Magnetic field configuration 2.14 T Pulsed coils or SC coils 2.0 – 3.0 T Pulsed coils Performed at Institute of Applied Physics Nyzhnyi Nogorod (Russia) – collaboration since 10 years Restrictions for high frequency operation and exploration (1 Hz - 10 Hz – 25 Hz …) Superconducting coils Extremely expensive – not yet proven feasible – ‘definitive’ configuration (not R&D) So static B and classical technologies (copper and water)

The 60 GHz Collaboration and The reality (beginning). The 60 GHz Collaboration and LPSC , Grenoble ECRIS development, low energy beam lines, beam analysis LNCMI, Grenoble Very High Magnetic Fields Collaboration since 2 years IAP, Nijni Novgorod, Russia Plasma physics, gyrotrons and pulsed ECRIS Collaboration since 10 years

The reality (Magnetic field) Courtesy of François Debray 3 Technologies for high field magnets Bitter Helix Widely used in main high field labs Developed at the LNCMI Longitudinally cooled Radially cooled Continuous change of the current density  allows a fine optimization of the current distribution ~ 1000 « high field » contacts variable pressure with B ~ 10 « low field » contacts independant of B  Improved field stability

The reality, Beams and plasmas physics WP4 : For beam bunching a high frequency ECR concept will be studied as a continuation of work started in EURISOL DS Pulsed ion beams afterglow and preglow effect studied 18 and 28 GHz Theoretical 60 GHz extrapolation higher intensity, shorter pulses IAP theory and LPSC exp. results comparison

First 60 GHz ECR ion source prototype: dream ? Magnetic structure expected: 2.1 Tesla closed ECR surface 4 Tesla radial confinement 6 Tesla at injection 3 Tesla at extraction Compact source (100 mm long) Structures using PolyHelix Technology Fast and cheap design and construction First prototype to Master the technique and the environment: 60 GHz CUSP 4 T 3 T 6 T Injection Extraction 2.1 T Field line 60 mm Peak to peak ~100 mm ECR zone Plasma chamber shape with shoulder

The reality : magnetic structure for 60 GHz ECR 3D Simulation with Getdp Exact geometry from CAD + mesher Thermal study 2.1T Injection Extraction H1 H2 H3 H4 Magnetic field lines Br

The reality : validation of the simulation B on axis (Gauss) Experiment Simulation Aluminum model of H1 coil (real size) Tested at 140 A (low current) Comparison with simulation : dB/B~3% Identical magnetic center Magnetic structure validated : OK to build Copper Coils Delivery mid april

Multi electrode extraction 60 GHz ion source diagram 100 kV insulation Gas V= 100 kV Ground V=0 polyhelix polyhelix Multi electrode extraction MW window Ions extraction 60 GHz Microwaves ECR polyhelix polyhelix insulator Water cooled plasma chamber

ECR Plasma 60 GHz ECR ion CAD Water cooling I– I+, 15000 A I– 600 mm 620 mm I– I+, 15000 A 490 mm ECR Plasma I– Size and cost reduction without changing Internal characteristics unchanged (B, cooling, plasma chamber) I+, 15000 A Water cooling

Technical specification : 60 GHz Gyrotron IN2P3 funding Technical specification : 100 kW max, 10 kW average 100 ms-15 ms pulses / 50 Hz IAP Focusing Lens Gycom Gyrotron 53 GHz 100 kW Gycom Gyrotron frame

How to get a 60 GHz Gyrotron and perform experiments? Use any external resources possible (collaborate!!) ISTC project: IAP Nizhny Novgorod (Plasma physics theory and experiments, gyrotron manufacturing) LPSC in this programme will be responsible of the design and construction of various ECR ion sources prototypes with specific magnetic field configurations designed with the help of LNCMI. Geert Rikken Director of the LNCMI LNCMI has committed itself to the magnetic characterization of the first prototype magnet, and is discussing the possibilities to reinforce our collaboration (i.e. a permanent room for experiments + electrical Power!!) Estimated total cost of the project (US $) 1 000 000 Financial Sources: Requested from the ISTC 710 000 Other financial source 1: LPSC 290 000

A place to perform experiments (1) 34 T /34 mm 19 T /160 mm ? Hydraulic pumps 1000 m3/h deionized water 28 GHz 15000 A, 2.5 MW 60 GHz 30000 A 5 MW Power supplies : 30 000 A, 24 MW

A place to perform experiments (2) A new dedicated 60 GHz test bench has to be built (in a place) Magnetic spectrometer developed in collaboration with M. Duval (GANIL) 150 mm GAP Θ=90° , ρ=700 mm 350 mm horizontal aperture 2,5 Tons Mass separation : 100 BρMAX=0.23 T.m Delivered by SIGMAPHI (IN2P3 funding) GAP 150 mm Xbeam= 350 mm Location of the test bench under discussion LNCMI Need high level political support !

Political strategy for the 60 GHz ECR ion source development and tests A part of the EUROnu deliverables list Del. no. Deliverable name WP no. Delivery date (proj. month) D2 Report on 1st year activities All 12 D8 Collection device construction 4 18 D9 Interim report 24 D12 Report on the experimental validation of the collection device for Li-8 30 D13 Bunching performance evaluation 35 D14 Project review documentation 36 D22 Final report 48

Tentative planning including deliverables

If we believe in a dream, we may succeed… If dream gets into reality… Conclusion If we believe in a dream, we may succeed… If dream gets into reality… There is a possible future: Beyond EURISOL and EURO-nu, We may have 15 years to work on cw (not pulsed) high frequency ECR Ion Sources ! Thank you for your attention !

Work characteristics : Current : 30000A Max density in 2 mm pitch helix part : J~650 A/mm2 Electrical Power : P~ 5 MW (6.5*) Water cooling, deionized water : Water cooling flow ~ 20 l/s Pin = 27 bars ; Pout = 4 bars Tinlet = 20 °C, Toutlet = 40 °C Max Coil temperature TMax loc. ~ 125°C (150*) Tmean ~ 95°C (115*) Mechanical characteristics Max Hoop stress : ~ 280 MPa << Elastic limit of Copper Alloy (380 MPa) Extraction and injection sides exerts each a force of 60 tons * Pessimist calculus

Production of B and Li B* and Li* are produced by irradiating a target. How is Boron or Lithium when it get out from the target? Atoms – Ions – Molecules? What are the possibilities? If we have molecules => they should be broken in the plasma If we have ions => use the 1+/n+ method Solutions: Metallic vapor, efficiency ~ 1 – 10 % Sputtering, efficiency ~ 1 % (energetic atoms) Extract species using offline chemical separation techniques, efficiency ~ 10 % 7Be is produced by irradiating a lithium target (30 μA of 27 MeV protons) and is extracted by this way (Loiselet et al. Louvain-La-Neuve) …