Ion confinement in electron cyclotron resonance ion sources
Main funder
Funder's project number: 4bdc70
Funds granted by main funder (€)
- 9 000,00
Funding program
Project timetable
Project start date: 01/10/2017
Project end date: 31/03/2019
Summary
The objective of the planned research is:
1. Development of a diagnostics method for the measurement of ion confinement time in conventional ECR ion source plasma at JYFL
The ion confinement time of various charge-state ions can be measured by injecting a pulse of neutral particles into the ECRIS plasma and observing the decay time of the corresponding ion current extracted from the ion source. The injection of the trace element can be realized by pulsing the high voltage of a metallic sputter sample placed into the plasma chamber.
Energetic ions drawn from the plasma towards the sample cause neutral atoms to be injected into the plasma. These atoms are then ionized and form a distribution of ions with different charge states. After the equilibrium charge state distribution is reached, the voltage applied to the sputter sample is switched off. Finally, the temporal evolution of the extracted currents of the metal ions is monitored. The characteristic decay time of the ion current signals is a direct measure of the ion confinement time.
The described approach has benefits over previously applied methods relying on pulsing the primary plasma either by controlling the injection of the plasma element or the microwave power sustaining the plasma.
2. Development of a diagnostics method for the measurement of ion confinement time in charge breeder ECR ion source plasma at GANIL
The 1+ beam injected into charge breeder ECRIS plasma can be pulsed. Hence, the confinement times of various charge state ions can be measured similar to the conventional ECRIS merely replacing the sputtering technique with the 1+ injection. Comparison of the confinement times obtained through different material injection schemes (neutrals vs. 1+ ions) allows assessing the reliability of the results and the diagnostics method.
3. Study the effect of momentum transfer in ion-ion collisions on the ion confinement times in ECRIS plasmas
The previously described diagnostics methods can be applied for a number of ion species combinations (both plasma ions and sputtered / injected ions). The research hypothesis is that varying the ratio between the ion masses affects the ion confinement time. Confirming this in systematic manner would provide proof for ion cooling being the explanation for increased efficiencies when gas mixing is applied. Furthermore, the study would allow distinguishing between capture and ionization efficiencies in charge breeder ECR ion sources, which would help optimizing their performances for applications.
1. Development of a diagnostics method for the measurement of ion confinement time in conventional ECR ion source plasma at JYFL
The ion confinement time of various charge-state ions can be measured by injecting a pulse of neutral particles into the ECRIS plasma and observing the decay time of the corresponding ion current extracted from the ion source. The injection of the trace element can be realized by pulsing the high voltage of a metallic sputter sample placed into the plasma chamber.
Energetic ions drawn from the plasma towards the sample cause neutral atoms to be injected into the plasma. These atoms are then ionized and form a distribution of ions with different charge states. After the equilibrium charge state distribution is reached, the voltage applied to the sputter sample is switched off. Finally, the temporal evolution of the extracted currents of the metal ions is monitored. The characteristic decay time of the ion current signals is a direct measure of the ion confinement time.
The described approach has benefits over previously applied methods relying on pulsing the primary plasma either by controlling the injection of the plasma element or the microwave power sustaining the plasma.
2. Development of a diagnostics method for the measurement of ion confinement time in charge breeder ECR ion source plasma at GANIL
The 1+ beam injected into charge breeder ECRIS plasma can be pulsed. Hence, the confinement times of various charge state ions can be measured similar to the conventional ECRIS merely replacing the sputtering technique with the 1+ injection. Comparison of the confinement times obtained through different material injection schemes (neutrals vs. 1+ ions) allows assessing the reliability of the results and the diagnostics method.
3. Study the effect of momentum transfer in ion-ion collisions on the ion confinement times in ECRIS plasmas
The previously described diagnostics methods can be applied for a number of ion species combinations (both plasma ions and sputtered / injected ions). The research hypothesis is that varying the ratio between the ion masses affects the ion confinement time. Confirming this in systematic manner would provide proof for ion cooling being the explanation for increased efficiencies when gas mixing is applied. Furthermore, the study would allow distinguishing between capture and ionization efficiencies in charge breeder ECR ion sources, which would help optimizing their performances for applications.
