Superconducting ECR

Date:21-07-2009   |   【Print】 【close

ECR ion sources are acknowledged internationally as the most effective facility, which can produce intensive ion beams of high charge state. With the ECR ion sources used in HIEFL, we have got the beam species, beam intensity and working efficiency greatly enhanced. In the past years, we also provided ion beams for the atomic physics separately, and a lot of internationally advanced results were obtained.

To further satisfy the strong requirements from HIRFL and RIBLL (Radiative Ion Beam Line in Lanzhou) of intensive multi-charged ion beam, as well as to provide the research of highly ionized state atomic physic, surface physics and low radiative beam with new conditions that we did not have before in China, we put forward to designing a high charge state superconducting ECR ion source. We design this ion source with the respect that some of the results of the extracted beams and the capability of the facility can be the advanced one in the world, and at the same time, make the techniques on ECR ion source manufacturing in China be the international leading station.

The SC-ECR system is mainly made up of ion source and the peripheral equipments, which includes microwave system, helium liquefying system, electric system, metallic ions generating facility and etc.

It is predicted that it will be 3 years for the SC-ECRIS to be accomplished and put into use. Now everything is on the way.

The purpose and the target of the SC-ECR Ion Source:

* To improve beam intensity of IMP cyclotron complex and satisfy the requirements of cooling storage ring.


* Intense heavy ion beams with very high charge states

Kr27+, Xe33+, Au35+, U41+ 20-50eμA (at 28GHz)

RIB; Super-heavy element; atomic physics; HIRFL-CSR

* Intense pulsed heavy ion beam

* To develop SC technologies at IMP

SECRAL (Superconducting ECR Ion Source with Advanced design in Lanzhou), is a next generation ECR ion source, and aims for developing a very compact superconducting ECR ion source with a completely new structure and high performances for highly charged ion beam production. The ion source was designed to be operated at 18 GHz at initial operation, and finally will be extended to 28 GHz. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. At full excitation, this magnet assembly can produce peak mirror fields on axis 3.7 Tesla at injection, 2.2 Tesla at extraction and a radial sextupole field of 2.0 Tesla at plasma chamber wall. What is different from the traditional design, such as LBNL VENUS and LNS SERSE, is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. SECRAL may open a new way for building a compact and high performance 18-28GHz superconducting ECR ion source.

  Typical parameters of SECRAL

Axial magnetic field (T)
3.7 at injection & 2.2 at extraction
Radial magnetic field at the chamber wall (T)
RF frequency (GHz)
18 or 28
Maximum RF power (kW)
ID of plasma chamber (mm)
LHe consumption (L/h)
Extraction HV (kV)

The SECRAL superconducting magnet assembly was constructed at ACCEL Instruments Inc, Germany. The fabrication contract was signed in April 2002. After more than two years’ redesign and fabrication, the SC-magnetic body can finally reach its 100% design working point. At the end of July 2005, the magnetic body of SECRAL source passed the final acceptance test in Lanzhou. The measured axial field distribution at 100% design currents (i.e. Isext= 138 A, Iinj= 193 A, Imid= 25 A and Iext= 164 A) on the axis with the sextupole operating is given in the right. This source was firstly ignited in August 2005. Very promising results have been obtained during the preliminary commissioning as is presented in the right.