AVF Cyclotron

The K70 AVF cyclotron has four spiral sectors and two rf dees with an angle of 85 degrees. Its mean extraction radius of 71.4 cm is the four-fifth of the mean injection radius of the RRC. The radio frequency is tunable from 12 MHz to 24 MHz; the harmonic number of 2 is used for acceleration. The maximum average field is 1.7 Tesla. This cyclotron can accelerate ions having a mass-to charge ration smaller than 4, up to 3.8 MeV/nucleon (at 12 MHz)-14.5 MeV/nucleon (at 24 MHz). It serves as the injector of RRC for ions lighter than copper.

Two types of external ion sources, an ECR ion source and a polarized ion source (under construction) are ion source is of a two-stage configuration, and 10GHz microwaves are applied to both stages. This source has been providing highly-charged very low-energy beams to atomic physics experiments as well.

Following figure shows the photograph of the AVF cyclotron.

Specifications of the AVF cyclotron.

External Ion Souce
	Type      	   ECR, Polarized ion Source

Injection
	Type	            Vertical injection with a spiral inflector

Main Magnet
	K-value  	    70 MeV
	No. of sectors      4
	Pole Diameter       1.7m
	Max. Flux Density   1.7 Tesla on the average
	Extraction Radius   0.714 m
	Trim coils	    9 pairs
	Harmonic Colis	    4 paires
	Weight		  110 tons

Acceleration System
        RF Amp. final tube  4CW50000E tetrode (EIMAC)
	No. of Dees	    2
	Dee angle	    85 deg.
	Frequency Range     12-24 MHz
	Frequncy Tuning     Shortin plate and trimmers
	Harmonic No.        2
	Charge/Mass Ratio  >= 1/4

Dimensions
	Diameter	   4 m
	Hight		   2.8m

Photograph of the ECR ion source

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last updated on 25 Oct 1996 by T.Ichihara (www-admin@rikvax.riken.go.jp)