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Ultra-High Current Density Producedby a 60 GHz ECR Ion Source
T. André1, T. Thuillier1, P. Sole1, M. Baylac1,J. Angot1, F. Debray2, I. Izotov3, V. Skalyga3
1Université Grenoble-Alpes, CNRS-IN2P3,Grenoble Institute of Engineering (INP), LPSC, 38000 Grenoble, France
2LNCMI, CNRS-UGA-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble, France3Institute of Applied Physics, RAS, 46 Ulyanova St., 603950 Nizhny Novgorod, Russian Federation
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020
60GHz ECR ion source History
• Sixty gigahErtz Ion Source usingMegawatt magnets• The source was developped during the
EURISOL design study project• Coils were constructed with the LNCMI,
where the experiment is installed• For the HF production, a Gyrotron, MW
beam line, optical injection in thesource done by IAP RAS NizhnyNovgorod• 60 GHz-300 kW/1 ms pulses/2 Hz
• First experimental session wasperformed in 2014 but stopped due to ametallic wire present in the water flowwhich damaged 2 of the 4 coils.• The project restarted in 2019 with fresh
IN2P3 funds
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 2
60GHz ECR ion source Experiment at GHMFL
Find the source! gyrotronMW Optical coupling
SEISMDipole
FaradayCup
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 3
60GHz ECR ion source Experiments in 2014
• 1mm diameter extraction electrode• Observation of current densities up to 900mA/cm2 in steady plateau• Observation of transient reproducible current densities up to 1.8A/cm2
𝐽!"!~900 mA/cm² 1.8A/cm²
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 4
60GHz ECR ion source Experiments in 2014
• Observation of afterglow peaks• Evidence of ion confinement in an ECR CUSP!
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 5
60GHz ECR ion source Experiments in 2014
• Afterglow peaks of different charge states are not synchronous in a CUSP• AFG peaks are synchronous in a classical Min-B ECRIS• Effect yet not understood
O1+O2+O3+O4+
O5+
time
Color is ion beam intensity
MW ON
MW OFF
MW
pow
er
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 6
60GHz ECR ion source SEISM future experiments
• New experiments to be scheduled in 2021
• Improve experiment:
• New plasma chamber→ improve the vacuum level (10−5→10−7 mbar)• Increase High voltage (30→40 kV)• Design of a new beam transport line→ add of a quadrupole triplet and dipole
with a larger gap (60→90mm)→ transmission improved• Installation of a new overhead crane→ optimize implantation of the experiment
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 7
60GHz ECR ion source Experiments foreseen
• Reproduce previous data
• Investigate further afterglow peaks
• Make systematic measurements as afunction of the source parameters• magnetic field, pressure, HF power,
biased radial ring
• Measure beam emittance with apepperpot
• Study plasma stability with appropriatedetectors• RF trigger, time resolved xray counter
• Lost electron energy distributionmeasurements
Plasma chamber of SEISMsource
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 8
60GHz ECR ion source Next steps of 60 GHz Source
PACIFICS EQUIPEX: Joint CEA / IN2P3 Research program application filed inJune 2020, including a work package dedicated to the enhancement of highintensity beams for the next generation accelerators
• Relocate the SEISM source at the LPSC→ Replace the resistive coils by SCones• Upgrade the 60GHz gyrotron HVPS to 20 kW - CW operation• Open the future equipment to collaboration with other communities
(Plasma, Astrophysics, ...)
Goal:
• Produce >100mA of a medium charge state ion beam in CW operationextending the collaboration to CEA IRFU experts• Investigate the 60GHz ECR plasma with diagnostics• Study beam emittance and space charge neutralisation
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 9
60GHz ECR ion source Pacifics Superconductive coils
• Preliminary design under progress, NbTi wire @4K considered• Objectives: Closed CUSP minimum B surface at 60GHz with ECR surface 1 cm
away from the plasma chamber• Example: CUSP configuration for a 250mm diameter plasma chamber
−0.4 −0.3 −0.2 −0.1 0.0 0.1 0.2 0.3 0.4
y [m]
0.0
0.1
0.2
0.3
0.4
x[m
]
Plasmachamber
2.140
2.140
2.140 2.140
1
2
3
4
5
• Oxford cables• Coil Loadlines <85%• 75 % Cu cable• 1.08*0.68 mm sec.
insulated
Parametric study
0 2 4 6 8
Magnetic f eld [T]
0
200
400
600
800
1000
Criticalcurrent[A]
Critical curve
Loadline D150
Loadline D200
Loadline D250
160 180 200 220 240
Chamber diameter [mm]
1.2
1.4
1.6
1.8
2.0
2.2
2.4
DistancebetweenECRsurface
andplasmachamber[cm]
160 180 200 220 240
Chamber diameter [mm]
4000
4500
5000
5500
6000
6500
7000
7500
Energystoredintergrated[J]
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 10
60GHz ECR ion source
THANK YOU FOR YOUR ATTENTION
XXIVth Workshop on ECR Ion Sources East Lansing, Sept. 28-30th 2020 11
