Practical Radiation Control at KEK

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Raymond Powers
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1 Practical Radiation Control at KEK

2 Scope of this talk Radiation Control (1) Exposure control KEK, Government (2)Controlled area Activation of beam line 12GeV-PS and the Utilizing Facilities Extraction beam line EP1, Neutrino Beam Line, Target Station 500MeV Beam Transport Line Another speaker will give more information: Professor Satoh Maintenance scenario Professor Kawakubo Practical maintenance experience Radio-activities and radiation exposure from the maintenance

3 Proton Accelerators 45MeV Linear Acc. ~ 30mA 500MeV Synchrotron ~ 6-10mA(3-5k W) 12GeV Synchrotron ~ mA (~3-8kW) 168h/w,2186h/3m (5000~ h / y ) Experimental Hall ( 168h/w,2186h/3m (4500h/y)) 12 GeV Protons ~ 0.58mA(~7kW) North Counter Hall (EP1 and Neutrino Beam Line) East Counter Hall (EP2 Beam Line) 500 MeV Protons ~ 10mA(~5kW)

4 Electron and Positron Accelerators Linear Accelerators 10GeV 0.625mA PF-AR Synchrotron 8GeV 0.25A PF Synchrotron 3GeV 0.6 A KEKB Synchrotron 10GeV 1A 5GeV 1A 168h/w,2186h/3m ( ~7 h / y )

8 Area KEK Design L a w Value Site Boundary 50 S v / y 250 Sv/3 m General Area 0.2 Sv/h Warning Area 1.5 Sv/h General Radiation Controlled Restricted Controlled Radiation Area Forbidden Radiation Controlled Area 20 S v / h 1.3mSv/3m (2.6 Sv/h) 1mSv/ w <100 m S v/h >100 m S v/h Ground Water activation 10 S v/y at site boundary from drinking water

9 F o r b i d d e n > m S v / h 2 0 S v / h < R e s t r i c t e d < m S v / h 1. 5 S v / h < G e n e r a l < 2 0 S v / h 0. 2 S v / h < W a r n i n g < 1. 5 S v /h F r e e o n S i t e 0. 2 S v / h P u b l i c S i t e B o u n d a r y < 5 0 S v / y

11 Daily Radiation Control (1) Radiation Dose (2) Access Control (3) Radioactive Material Control (4) Exposure Control Control Scheme is di fferent during operation, during maintenance after operation

12 During Operation High energy neutrons (1 100MeV) i n t h e experimental area. Access to the beam line is strictly controlled by interlock system. Radiation controlled area, experimental hall, are monitored continuously to watch the radiation level. Radiation workers and experimentalists, who enter radiation controlled area, are recorded automatically by card system.

13 A f t e r s t o p p i n g o p e r a t i o n, M a i n t e n a n c e i n s i d e b e a m l i n e m u s t b e r e s t r i c t e d. P r o c e d u r e t o s t a r t m a i n t e n a n c e i n s i d e b e a m l i n e : 1 ) m e a s u r e r a d i a t i o n d o s e a l o n g b e a m l i n e, 2 ) w r i t e p r o p o s a l f o r m a i n t e n a n c e w h o, w h e r e, w h e n, h o w 3 ) i f t h e m a i n t e n a n c e i s a t a h i g h r a d i a t i o n p l a c e, p e r m i s s i o n f r o m r a d i a t i o n o f f i c e r, a p e r s o n i n c h a r g e o f t h e f a c i l i t y, p l a n t o p r o c e e d t h e m a i n t e n a n c e t o a v o i d h i g h e x p o s u r e, s h i e l d i n g, i n d i v i d u a l w o r k i n g t i m e, m a n y p e o p l e t o d i s t r i b u t e e x p o s u r e, k e y p e r s o n m u s t b e a w a y f r o m r a d i a t i o n w o r k t i l l n e c e s s a r y. 4 ) E v e r y o n e m u s t c a r r y a n a l a r m d o s i m e t e r, T h e r e s p o n s i b l e p e r s o n m u s t c o n t r o l a n d o r g a n i z e.

15 Induced Radio- activities and Radiation Field 1 2 G e V P S R i n g a n d R e l a t e d F a c i l i t i e s E x t r a c t i o n S e p t u m M a g n e t s p p s ( 5. 7 k W ) f o r E P 1 F a s t E x t r a c t i o n p p s ( 1. 9 k W ) f o r E P 1 S l o w E x t r a c t i o n C o u n t e r H a l l T 5 a n d T 6 T a r g e t ( P T 6 c m ) p p s N e u t r i n o T a r g e t s t a t i o n N e u t r i n o P r o d u c t i o n T a r g e t ( A L 6 5 c m ) p p s M e V U t i l i z i n g F a c i l i t y N e u t r o n a n d M e s o n L a b o r a t o r y ( N M L ) B e a m T r a n s p o r t L i n e P 4 L i n e f o r s l o w m u o n P r o d u c t i o n

16 12GeV-NCH(sec. 2) 12GeV-ECH (sec. 2) PS-MR (Sec. 1) PS-Linac (sec. 1) PS-BS (sec. 1) 500MeV-NML (sec. 3)

17 100mSv/h EP1:12GeV 10mSv/h 1mSv/h Injection 500MeV EP2 12GeV

18 EP1 Extraction(25/12/ 02) EP2 Extraction(25/12/ 02)

19 3 weeks cooling EP1 EP2

20 North Counter Hall (K5 and K6 Experimental Area) EP1 Beam Line, Neutrino Beam Line EP1-A, Experiment Utilizing Primary Proton Beam 12GeV; 0.16nA ( p p s) EP1-B, 1) Production of Secondary Particles, p, K Target T5(PT6cm): K5 Exp. Area Target T6(PT6cm): K6 Exp. Area 2) Transmit Proton Beam to Neutrino Target Station Neutrino -TS AL target 65cm 2cm diameter 12GeV;Max 0.576mA ( p p s,6.9kw)

21 Dose Rate (msv/h) GeV Protons 1.0(3.0)E+12 P/s for 30 days irradiation on PT(AL) (MARS calculation) AL-65cm PT-6cm Na Time (hours) Na-22

22 Neutron and Meson Science Laboratory, NML Beam Line 500MeV, MAX:9.6mA ( p p s) Neutron Experimental Hall Production Target W with Ta clad 2.9cm 4 Meson Experimental Hall Meson No.1 Laboratory Meson No.2 Laboratory (P-4 Beam Line)

23 Dose rate created by induced activities 12GeV-PS extraction septum magnets Dose Rate (msv/h) Beam Loss Max Average 400W W ~20 1~5 8h cooling 3w cooling Target (EP1) in 12GeV-PS Related Facilities PT (6cm) 960W 1000 Near Target 50~100 3 d cooling

24 KEK Working Level of Exposure Control C l o s e C o n t a c t 0.5 msv/d 30 minutes/d at 1mSv/h 3 minutes/d at 10mSv/h 1 msv/w 2 days/w 7 msv/y 7 weeks/y Planning maintenance 1 ~ a few hours

Estimation of Radioactivity and Residual Gamma-ray Dose around a Collimator at 3-GeV Proton Synchrotron Ring of J-PARC Facility

Estimation of Radioactivity and Residual Gamma-ray Dose around a Collimator at 3-GeV Proton Synchrotron Ring of J-PARC Facility Y. Nakane 1, H. Nakano 1, T. Abe 2, H. Nakashima 1 1 Center for Proton Accelerator