372596207

209

RIKEN Accel. Próg. Rep. 24 (1990)

VI-3. Leakage Radiation Measurements in the Ring Cyclotron Facility

S. Fujita, N. Nakanishi, T. Shikata, K. Ikegami, T. Takagi, S. Okamoto,

I. Sakamoto, T. Inamura, and H. Kamitsubo

The radiation safety control system has work-

Table 1. Dose rates of neutron leakage radiation from a target point A in extended experimental vault E5 (see Figs. 1-a,b).

Measured point	Dose rates (u Sv/h)	Measured point	Dose rates (m Sv/h)
a	0.56	S	0.002
b	0.34	h	0.006
c	0.033	• i	125
d	0.002	3	14
e	0.010	k	0.125
f	1.80

Table 2. Dose rates of neutron leakage radiation from a

target point B in the beam distribution corridor. (see Figs.l- a,b,c.) A letter “A” stands for the neutron dose ratę meter of 2202D Studsvik No.83064; “B” for 2202D of Studsvik No.89006; “C” for 2202D of Studsvik No. 86032; and “D” for NSN1001 of Fuji electric.
Measured point	Doicclo r n ame	Coun l rates (C/3rain)	Dose rates (#Sv/h)
( 1 )	11	0	0
( 2 )	A	0	0
( 3 )	c;	2	0. 03
( 4 )	c	17	0. 22
( 5 )	c	89	1.15
( 6 )	11	1 84	3. 1 0
( 7 )	A	38	0.64
( 8 )	c:	4	0. 05
( 9 )	11	2	0. 03
(10)	11	0	0
(11)	c;	0	0
(12)	n	0	0
(13)	c	0	0
(14)	11	0	0
(15)	A	0	0
(16)	C	3	0. 04
(17)	O	42	0. 54
(18)	c	6	0. 08
(19)	c	34	0. 44
(20)	B	9	0.15
(21)	15	5	0. 08
(22)	11	22	0. 37
(23)	B	1 1 0	1.85
(24)	11	6	0. 1 0
(25)	11	82	1. 38
(26)	c:	15	0. 1 9
(27)	11	0	0
(28)	B	0	0
(29)	1)	—	0. 002
(30)	1)	-	0. 002
(31)	I)	—	0. 020
(.32)	1)	—	0.0 18
(33)	1)	—	0. 029
(34)	1)	-	0. 006
(35)	n	—	0. 055
(36)	D	-	0. 040
(37)	1)	-	0. 029
(38)	1)	-	0. 059
(39)	1)	—	0. 0 30
(40)	I)	-	0. 006

(c)

Fig. 1. Layout of RIKEN Ring Cyclotron facility as of 1990. a : Plan view of basement 2th floor; b : Plan view of basement lth floor; c : Plan view of first floor. Leakage radiation doses measuring points are denoted by alphabets and the number in the parentheses.