RF System and EBIS of RAON JaeEun Han IF & RF Team

Contents RF System - Introduction to RF System of RAON EBIS System - Low Level RF - High Power RF - 1 kW SSPA Simulation & RF Power Test - 2 kW Unit Test - 5 kW RF Power Test EBIS System - Introduction to EBIS System of RAON - Breeding Simulation Result - Electron Gun Simulation Result Summary

RF System of RAON

Low Level RF The RF input has 4 identical channel. ADC has sampling rate higher than 120 MHz. Calculation of magnitude and phase errors using the output signals of the ADC are performed in the FPGA. The RF output signal is generated through the FPGA, DAC, IQ modulator and a low-power RF amplifier.

High Power RF Schematic diagram of Solid state power amp. for QWR To produce the power of 2 kW, two modules of 1 kW SSPA are combined, and another 2 way combiner is used to generate RF power of 4 kW

Simulation of 1 kW SSPA Circuit Diagram for 1 kW SSPA (Using ADS code) Most MOSEFT is limited by 500 W of RF power  push pull mode

Test of 1 kW SSPA

Comparing the result of simulation with test Power vs. Gain Test Result Simulation Result In comparison with simulation, measurement does not show the peak of power gain near 55 dBm, but the value is not far different.

2 kW Unit Test RFIN Test Result (Spectrum Analyzer) 2 kW Unit SMB035 2-WAY SPLITTER 2-WAY COMBINER 3W AH-101 AH-202 SMB036 RFIN Test Result (Spectrum Analyzer) 2 kW Unit

5 kW High Power RF Test SSB034 (5KW) SSB035 (2KW) RFOUT RFIN 4-WAY SPLITTER 4-WAY COMBINER 2-WAY SPLITTER 2-WAY COMBINER SMB035 (1.2KW) SMB036 AH-101 AH-202 300W RFIN RFOUT SSB036 (Drive & 4-way Combine)

Power versus Frequency (W/ Spectrum Analyzer) 5 kW RF Power Test Result Power versus Frequency (W/ Spectrum Analyzer)

EBIS System of RAON Electron Collector and Ion extractor Drift Tube Structure Electron-Gun EBIS operation mechanism Electron beam is generated in electron gun, and ion beams having +1 charge enters drift tube, and then, this electron impact ion beam. As a result, highly charged ions are created in the drift tube By controlling potential, electron beam is dumped to collector, and ion beam goes back where they come out.

Design parameter for RAON EBIS RISP Test EBIS Breeding efficiency 30 % A/q > 4 Breeding time 50 ms ( Light Ion) 150 ms (Heavy Ion) Beam purity < 0.1 pA Ion Beam Intensity 2 X 10^9/pulse Pulse width 10 ~ 20 us Repetition rate 2 Hz

Charge Breeding Simulation CBSIM Input Variable Description NORDER order number of Element,(H,U,etc) ENERGY energy of electron beam ALPHA neutral influx: 0 < alpha < 1 DELTAU radial potential in electron trap HEAT toggle for electron-ion-heating dens electron current density logT1 begin of log10(T)-axis logT2 end of log10(T)-axis logTc time for onset of compensation Nstep steps of integration < 5002 ERROR error criterion for Runge-Kutta LOGSCALE log scale for abundances logP1 begin of log abundance axis logP2 end of log abundance axis LABEL Labels at closed shells RECOMB radiative recombination toggle CHEXCH charge exchange toggle mbar background pressure for ChEX Epgas ionization potential of background gas NSPECT number of charge spectra WSPECT resolution for charge spectra

Charge Breeding Simulation Sn 1s22s22p63s23p64s24p64d105s25p2 K shell : 29.2001 keV L shell : 4.46470 keV Electron atomic binding energy Sn+41 Sn+30 Sn+31 Sn+32 Sn+33

Charge Breeding Simulation Sn+47

Charge Breeding Simulation Charge exchange and radiative recombination effect excluded. Sn+32 Sn+30 Sn+31 Sn+33

Charge Breeding Simulation Sn+47 Sn+32 Sn+30 Sn+33 Sn+31 If we take into account expected A/Q value less than 4 for Sn 132, its charge state is around 33+. Its abundance will be approximately 20 %

Electron Gun parameter Current (A) AK Voltage (kV) Perveance (uP) Cathode diameter (mm) Currentdensity (A/cm^2) electron beam energy (keV) BNL EBIS 10 50 0.9 9.2 575 20 MSU EBIT 1.4 11.5 1.1 3 　104 16.5 2.4 1.9 6 REX EBIS 0.5 6.5 1 125 5 RAON EBIS Electron Gun parameter Current 0 ~ 10 A AK Voltage 0 ~　50 kV Current Density 500 A/cm2 Electron Beam Energy 20 keV

Simulation Result (Using E_gun code) - AK Voltage = 50 kV Current density (@ anode exit) Electron beam Trajectory Electrode Anode Radial direction Cathode Electron Beam Current, I = 11.23 A Average current density J = 144 A/cm2 Cathode radius 8.2 mm Perveance 1 uP

Theory (Child Langmuir law) Changing AK Voltage AK Voltage (kV) Current (A) Theory (Child Langmuir law) Simulation Result 10 1.01 20 2.86 2.84 30 5.25 5.23 40 8.08 8.13 50 11.29 11.23

Simulation Result - optimization Electron beam Trajectory Current density (@ drift tube exit) 50 kV 20 kV 50 kV Drift tube Post anode 0V Anode Cathode radius 7 mm Perveance 0.96 uP Drift tube radius 20 mm Current, I = 10.2 A Average current density J = 2570 A/cm2

RF System EBIS System Summary - The design of Low Level RF is optimized. - 5 kW RF power test is done. EBIS System - I have to study more Breeding Simulation. - The design of Electron Gun is optimized for Pierce gun type.