Status report on electron cyclotron resonance ion sources at the Heavy Ion Medical Accelerator in Chiba

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The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

Section: Introductionmentioning

confidence: 99%

Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

Biri

Kitagawa²,

Muramatsu³

et al. 2013

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“…At the beginning of HIMAC operation in 1994, a low-duty pulsed PIGIS, named NIRS-PIG, 10 and a 10 GHz ECRIS, named NIRS-ECR, 11 covered all requirements between He and Ar. However, NIRS-ECR was mostly occupied in the production of carbon ions for treatments, and there was hesitation to interrupt stable operation by the production of other ion species.…”

Section: B 18 Ghz Nirs-hec Ecr Ion Sourcementioning

confidence: 99%

Recent developments of ion sources for life-science studies at the Heavy Ion Medical Accelerator in Chiba (invited)

Kitagawa¹,

Drentje²,

Fujita³

et al. 2015

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With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.

Status report on ECR ion sources at HIMAC

Kitagawa¹,

Muramatsu²,

Sasaki³

et al. 2004

The Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS) is the first heavy-ion accelerator complex dedicated to cancer therapy. Over 1600 patients have already been treated with 140–400 MeV/amu carbon beams since 1994. The production of carbon ions for medical applications has been established. It is quite obvious from our experiences that the ECR ion source is an extremely suitable type of ion source for this purpose. An 18 GHz ECR ion source is mainly operated to offer various heavy-ion beams for basic experiments of biomedical science, physics, chemistry, etc. The results of recent developments, a thermal-controlled MIVOC system, and an electron bombardment evaporator are also reported.