As mentioned above, it is necessary to establish an electric system for the high-voltage use of EBIS. In particular, since several parts of high-voltage platforms, including the EBIS platform, are used, appro- priate power supplies and amplifiers for each platform should be used. Figure 3.18 shows the schematic diagram of four HV platforms used in the EBIS. Each platform consists of the EBIS platform for charge breeding, the cathode platform for electron beam extraction and transmission, the repeller platform for using the beam optics at the repeller’s potential, and the ion source platform for extracting the test ion beam. Since each platform is configured with a high voltage, the electric power is transferred over the platform using an insulated transformer.
The voltage of the EBIS platform is adjusted using two high-voltage amplifiers. The potential of the breeding region is determined by the sum of the voltage of the drift tube in there and the voltage of the EBIS platform. And the energy of the singly charged beam entering the EBIS is determined by the value set by the ISOL system, currently planned as 20 keV. Conversely, the energy per charge of the extracted beam should be possible up to 60 keV/q. Therefore, the potential of the EBIS platform should be set differently when the ion beam enters and exits, so high-voltage amplifiers, not power supplies, are used.
One of the two is a +30 kV positive amplifier, TREK P0621P-H, which is placed on the ground platform,
RepellerDT #11 AP #01 AP #02DT #10DT #09DT #08DT #07DT #06DT #05DT #04DT #03DT #02DT #01Cathode Rep. Lens PS
Anode Amp.DT #01 PSDT #07 Amp. Cathode Platform
Collector PS Repeller Plt. PS
HV Platform Power Supply Collector SteererEinzel LensAnode Ion Source Platform
EBIS Plt. Amp. #01
EBIS Plt. Amp. #02Lens Extractor
Rep. Steerer Amp. x4 IS Plt. PS
Heater PSExtractor Amp.Lens Amp.
Collector Coil AP #02 PS Ion Source
Collector Coil PS EBIS Platform
SC Magnet PSSteering Coil PS Gun Coil Gun Coil PS
SC Magnet DT #11 PS Cathode Plt. PSCathode Platform
RepellerRepeller Steering Coil
DT #02 PSDT #03 PSDT #04 Amp.DT #05 Amp.DT #06 Amp.DT #08 Amp.DT #09 PSDT #10 PS AP #01 PSRepeller Platform
Heater PS
Figure 3.18: Schematic drawing of EBIS power supply system for HV platforms.
and its ground jack is grounded. Another is placed on the EBIS platform with a±20 kV bipolar, TREK 20/20C-HC, and its ground jack is connected to the EBIS platform to form the platform’s potential.
The amplifier on the ground generates a positive output, and the amplifier on the high voltage platform generates a negative output to connect the outputs to each other. So, the EBIS platform voltage is applied up to 50 kV by two amplifiers. If the voltage of the drift tube in the breeding region is applied up to 10 kV, the energy per charge of the ion beam ejected from the EBIS can be adjusted to 60 keV/q. For DT
#08 for gating the trap and the anode for the electron beam extraction, their voltages need to be changed over time, so high voltage amplifiers were used, TREK 10/40A-HS of +10 kV and TREK 20/20C-HS of±20 kV, respectively. Additionally, DT #04∼08, the drift tubes in the breeding region use voltage functions with respect to time to adjust the beam length when extracting the highly charged ions. So they use high-voltage amplifiers, TREK 10/10B-HS, although the rest of the electrodes used power supplies manufactured by Matsusada Precision. In addition, since all magnets, including the superconducting magnet, are also on the EBIS platform, as shown in Fig. 3.9, the power supplies for magnets are also configured on the platform. Especially if the He compressor used for the SC magnet stops, the liquid He will be evaporated, and the superconducting state cannot be maintained. So all devices related to the SC magnet are supplied power via UPS (Uninterruptible Power Supply), which can provide the electrical power for 2 hr independently, even in a blackout. Figure 3.19 shows pictures of the configured electrical system installation of the EBIS high-voltage platform.
(a) Power supplies for drift tubes and normal conducting magnets.
(b) HV amplifiers for drift tubes and EBIS platform.
UPS
Isolation Transformer
He Compressor
Power Supplies for SC Magnet
(c) Electric system of SC magnet.
Figure 3.19: Electric system of EBIS HV platform.
The cathode platform for the electron gun determines the energy of the electron beam in the breeding region. So, it is applied voltage by the power supply manufactured by Matsusada Precision in the EBIS platform because it must have relative potential to the EBIS platform. Therefore, the heater power supply for increasing the temperature of the cathode is configured on the cathode platform so that its voltage determines the energy of the electron beam. The path through which the electron beam is transmitted is collected from the collector by emitting up to 3 A from the heater power supply. The power supply for
a high voltage and high current, SMART 0624 (8.0 kV / 3.1 A) by Dong-A Hitec, used for the collector is installed on the cathode platform so that this current loop occurs on one platform. In addition, to properly reflect the electron beam in the collector section, the repeller must have a voltage higher than the cathode. Thus, it is applied a voltage by configuring a negative power supply manufactured by Matsusada Precision on the cathode platform, which also applies the voltage as the repeller platform.
The power supply devices for the beam optics system connected to the repeller are configured on the repeller platform to which the voltage is applied. A positive high-voltage power supply is installed for the Einzel lens, and four high-voltage amplifiers are installed for the steerers to use different voltages when the ion beam enters and exits.
The ion source platform for the use of test ion beams has been separately constructed. The power supply for this ion source platform used a high voltage power supply, SHV120R-40kV-P by ConverTech to control the energy of the ion beam. In the HV platform, the heater power supply is used to transfer heat to the ion source pellet, and the amplifiers, TREK 2220, for the extraction electrode and the Einzel lens are used. The voltage of the extraction electrode should be changed over time to emit the test ion beam as a pulse, so it is essential to use an amplifier. The electric system in the remaining high-voltage platforms, except for the EBIS platform, was installed, as shown in Fig. 3.20.
(a) Power supplies for cathode plat- form.
(b) Electric system of ion source plat- form.
(c) Power supplies for repeller platform.
Figure 3.20: Electric system of cathode, ion source and repeller HV platform.
In addition to the high-voltage platforms, various power supplies and amplifiers are used in the ground platform with ion transmission lines. Figure 3.21 illustrates the configuration of the electrodes and the power supplies for each line in the ion transportation line, and the electric system was configured according to each use.
The Einzel lens and the steerers used in the beam optics system in the switchyard line are used to adjust the size and direction of the beam when the ion beam enters and exits the EBIS, respectively.
High-voltage amplifiers, TREK P0621P-H (+30 kV) for the lens and TREK 2220 (±2 kV) for the steerers, are used because the voltage must be changed according to the timing of the ion beam injection and extraction. The switchyard electrode determines where to use the ion beam from and where to
Y-Steerer
Ground Platform Power Supply EQT LineSwitchyard Line Diagnostics LineIon Source Line
15deg Deflector Deflect orDeflect orSteerer Amp.EQT Side
Einzel LensSteererEQTXY-SteererSwitchyard Steerer Amp. IS Einzel LensDipole Magnet Diag. Steerer
Switchyard #01 Amp.Switchyard #02 Amp. Dipole Magnet PSDiag. Lens PSDiag. Steerer PS x4IS Line Lens PSIS Line Steerer PS x4
GroundGround Diag. Einzel Lens
EQT Center PS (+/-)GND Lens Amp.GND Steerer Amp. x4 IS Steerer
Figure 3.21: Schematic drawing of EBIS power supply system for ground platform.
send the charge-bred beam, also using a high-voltage amplifier, TREK 20/20C-HS (±20 kV), to adjust the voltage to the timing. The beam optics system of the ion source line for using a test ion beam is also used. The test ion beam extracted from the previously described ion source platform is allowed to stably enter the switchyard line by the Einzel lens and steerers after accelerated by the platform voltage. In the ion source line, the HV DC power supplies, SHV120R-40kV-P (+40 kV) manufactured by ConverTech for the lens and 1HVA24-BP1 (±1 kV) by UltraVolt, Inc. for steerers, are used. They do not use amplifiers, because the direction of the ion beam is one direction. Einzel lenses and steers are also used in the diagnostics line to measure the charge-bred residual gas and ion beams. This line also uses high-voltage power supplies, AU-30P10 by Matsusada Precision for the lens and SHV30M by ConverTech for the steerers because ions are transmitted in one direction. In addition, the specifications of the dipole magnet is shown in Table 3.1. From its specification, the magnet is operated using a power supply, EX 50-48 manufactured by ODA Technology, with a maximum current of 50.4 A. Finally, the EQT line is equipped with the EQT for focusing the beam and the steerers for steering, and the 15- degree deflector for selecting the direction of the beam at the EBIS branch point is used. The EQT uses power supplies up to 3 kV, SHV30R (+3 kV or -3 kV)by ConverTech, to apply the voltage. And high-voltage amplifiers, TREK 2220 (±2 kV), apply different voltage on the steerers when the beam enters and exits. The deflector at the EBIS branch point bends the beam toward the EBIS when it enters from the ISOL beamline. Conversely, when the beam exits from the EBIS, 0 V is set to transmit in a straight line direction. Therefore, the voltage of the 15-degree deflector is adjusted according to timing using high-voltage amplifiers, TREK 20/20C-HS (±20 kV). Figure 3.22 illustrates the installation status
(a) Ion source and diagnostics line.
(b) Switchyard line. (c) EQT line.
Figure 3.22: Electric system of ground platform.
of the electric system, including the power supply used for each line in the ground platform.
The electrical system of all electrodes with not only the high-voltage for the extraction of test ion beams and the electron beam extraction and transmission but also the transportation of the ion beam from and to the ISOL beamline in the EBIS has been constructed. All power supplies and HV amplifiers in this electrical system are configured with a control system to enable the remote control for future experiments.