ECRIS-2014 - List of Authors (Rodrigues, G.O.)

Paper

Title

Page

Frequency Tuning Effect On The Bremsstrahlung Spectra, Beam Intensity And Shape In An ECR Ion Source

15

G.O. Rodrigues, D. Kanjilal, N. Kumar, K. Mal, Y. Mathur
IUAC, New Delhi, India
A. Roy
VECC, Kolkata, India

The effect of the frequency tuning on bremsstrahlung spectra, beam intensity and shape in the 10 GHz, Nanogan ECR ion source have been investigated. The main aim of this work was to study the effect on a lower frequency type of ECR source where the separation between various modes in the cavity is much larger. The warm and cold components of the electrons were observed to be directly correlated with the beam intensity enhancement in the case of Ar⁹⁺ but not so for O⁵⁺. However, the warm electron component was much smaller than the cold component. The beam shapes of O⁵⁺ measured as a function of frequency showed a strong variation without hollow beam formation. Due to the use of an octupole magnetic structure in the Nanogan ECR source, the quadrupolar structure of the ECR surface is modified with the frequency tuning. In general, we have observed a strong absorption of microwave power at various frequencies whenever the reflection co-efficient showed a minimum value and the effect was seen stronger for the higher charge states. Details of the measurements carried out on the bremsstrahlung spectra, beam intensity and shape are presented together with the results of simulations.
* Effect of frequency tuning on bremsstrahlung spectra, beam intensity, and shape in the 10 GHz NANOGAN electron cyclotron resonance ion source, Rev. Sci.Instrum. 85,02A944 (2014)

Slides MOOBMH03 [23.075 MB]

MOPPH006

Direct Injection of Intense Heavy Ion Beams from a High Field ECR Ion Source into an RFQ

52

G.O. Rodrigues, D. Kanjilal
IUAC, New Delhi, India
R. Becker
IAP, Frankfurt am Main, Germany
R.W. Hamm
R&M Technical Enterprises, Pleasanton, California, USA

Beam intensities achievable from high performance ECR sources for highly charged ions are limited by the high space charge. For high performance ECR sources, the stray magnetic field of the source can provide focusing against the space charge blow-up of the beam in addition to the Direct Plasma Injection Scheme (DPIS) adapted from laser ion sources*. A combined extraction/matching system** has been designed for direct injection into a radio frequency quadrupole (RFQ) accelerator, allowing a total beam current of 10 mA for the production of highly charged 238U⁴⁰⁺ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The RFQ has been designed to suppress neighbouring charge states and to work as a filter for the desired 238U⁴⁰⁺. This reduces the transport problem for the beam line as well as it reduces the emittance for the selected charge state.
* R. Becker et al., PROC. EPAC-2004, TUPLT024
** G.Rodrigues et al., Rev. Sci.Instrum. 85,02A740 (2014)

Paper	Title	Page
MOOBMH03	Frequency Tuning Effect On The Bremsstrahlung Spectra, Beam Intensity And Shape In An ECR Ion Source	15
	G.O. Rodrigues, D. Kanjilal, N. Kumar, K. Mal, Y. Mathur IUAC, New Delhi, India A. Roy VECC, Kolkata, India
	The effect of the frequency tuning on bremsstrahlung spectra, beam intensity and shape in the 10 GHz, Nanogan ECR ion source have been investigated. The main aim of this work was to study the effect on a lower frequency type of ECR source where the separation between various modes in the cavity is much larger. The warm and cold components of the electrons were observed to be directly correlated with the beam intensity enhancement in the case of Ar⁹⁺ but not so for O⁵⁺. However, the warm electron component was much smaller than the cold component. The beam shapes of O⁵⁺ measured as a function of frequency showed a strong variation without hollow beam formation. Due to the use of an octupole magnetic structure in the Nanogan ECR source, the quadrupolar structure of the ECR surface is modified with the frequency tuning. In general, we have observed a strong absorption of microwave power at various frequencies whenever the reflection co-efficient showed a minimum value and the effect was seen stronger for the higher charge states. Details of the measurements carried out on the bremsstrahlung spectra, beam intensity and shape are presented together with the results of simulations. * Effect of frequency tuning on bremsstrahlung spectra, beam intensity, and shape in the 10 GHz NANOGAN electron cyclotron resonance ion source, Rev. Sci.Instrum. 85,02A944 (2014)
	Slides MOOBMH03 [23.075 MB]

MOPPH006	Direct Injection of Intense Heavy Ion Beams from a High Field ECR Ion Source into an RFQ	52
	G.O. Rodrigues, D. Kanjilal IUAC, New Delhi, India R. Becker IAP, Frankfurt am Main, Germany R.W. Hamm R&M Technical Enterprises, Pleasanton, California, USA
	Beam intensities achievable from high performance ECR sources for highly charged ions are limited by the high space charge. For high performance ECR sources, the stray magnetic field of the source can provide focusing against the space charge blow-up of the beam in addition to the Direct Plasma Injection Scheme (DPIS) adapted from laser ion sources. A combined extraction/matching system* has been designed for direct injection into a radio frequency quadrupole (RFQ) accelerator, allowing a total beam current of 10 mA for the production of highly charged 238U⁴⁰⁺ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The RFQ has been designed to suppress neighbouring charge states and to work as a filter for the desired 238U⁴⁰⁺. This reduces the transport problem for the beam line as well as it reduces the emittance for the selected charge state. * R. Becker et al., PROC. EPAC-2004, TUPLT024 ** G.Rodrigues et al., Rev. Sci.Instrum. 85,02A740 (2014)