1. 1 Energy Deposition of 4MW Beam Power in a Mercury Jet Target X. Ding, D. B. Cline UCLA H. Kirk, J. S. Berg BNL The International Design Study for the Neutrino Factory FNAL April 8-10, 2010

2. 2 Outline 1.Introduction 2.Target Geometry 3.Energy Deposition from MARS15 4.Comparison with FLUKA 5.Power Distribution, radiation dose and life time for SC1 coil 6.Summary

3. 3 Introduction Using MARS15 to study energy deposition. Study II geometry and magnetic field map. Hg jet: r=0.5cm, tilt 100mrad to sol. axis. Proton beam: Simple Gaussian distribution, r=0.15cm, tilt 67mrad to sol. axis.

4. 4 Introduction (Cont’d) The unit of energy deposition is GeV or GeV/g p.p (GeV per gram per incident proton). The number of particles for (4MW, 10GeV) proton beam is 2.5*10 15 s -1 (an average beam intensity in particles per second). (2.5*10 15 )*(10*10 9 )*(1.6*10 -19 )*10 -6 =4MW

5. 5 Target Geometry

6. 6 Target Geometry (Cont’d) Res Sol Hg Jet SC1 SC2 SC3 SC4 SC5 FeCo Pre-Trgt Air BeWindow (z=600cm) Hg Pool WC Shield STST Env (Bottle) Hg Jet

7. 7 Energy Deposition of 4MW Beam Power Regional Name ED [GeV]P [kW]P/P beam [%] WC shield4.61837.646.0 Hg Jet1.065426.010.7 STST Env1.1746811.7 Res Sol2.62*10 -1 104.62.6 Hg Pool4.89*10 -2 19.50.5 FeCo2.25*10 -2 9.00.225 Be Window6.22*10 -3 2.50.06 Pre Trgt< 10 -3 ----- Air< 10 -3 -----

8. 8 Energy Deposition of 4MW Beam Power (Cont’d) Regional Name ED [GeV]P [kW]P/P beam [%] SC15.52*10 -2 22.10.55 SC25.99*10 -3 2.40.06 SC33.30*10 -3 1.30.03 SC41.19*10 -3 0.50.01 SC52.87*10 -4 0.120.003 SC61.98*10 -4 0.080.002 SC78.70*10 -3 3.50.09 SC83.71*10 -3 1.50.04 SC92.18*10 -3 0.90.02 SC101.81*10 -3 0.70.02 SC111.33*10 -3 0.50.01 SC128.69*10 -4 0.350.01 SC136.51*10 -3 2.60.07

9. 9 Distribution of Energy Deposition The energy deposition in SC1 coil is between 10 -8 and 10 -10 [GeV/g per incident proton].

10. 10 Comparison with Fluka Power Deposition in NuFact Target, J. Back (Warwick, Dec 8, 2009). (http://www.hep.princeton.edu/~mcdonald/mumu/target/index.html#2nd_OP_workshop)Power Deposition in NuFact Target

11. 11 Comparison with Fluka (Cont’d) RegionP [kW] % (MARS15)P [kW] % (FLUKA) Hg Jet Hg Pool inside WC shield WC shield (z < 27 cm) WC shield (z ≥ 27 cm) Outer Fe yoke (z < −165 cm) Inner Fe yoke (z ≥ −165 cm) Inner Cu coil (18 ≤ r ≤ 23 cm) Outer Cu coil (23 < r ≤ 49 cm) SC Coil 1 SC Coil 2 SC Coil 3 SC Coil 4 SC Coil 5 SC Coil 6 SC Coil 7 SC Coil 8 SC Coil 9 SC Coil 10 SC Coil 11 SC Coil 12 SC Coil 13 Be window at 6m 426.0 10.7 19.5 0.5 1837.6 (WC shield) 46.0 468 (STST Env) 11.7 9.0 0.2 (FeCo) 104.6 2.6 (Res Sol) 22.1 0.6 2.4 0.1 1.3 ----- 0.5 ----- 0.1 ----- <0.1 ----- 3.5 ----- 1.5 ----- 0.9 ----- 0.7 ----- 0.5 ----- 0.4 ----- 2.6 ----- 2.5 ----- 400.9 10.0 12.5 0.3 1845.5 46.1 848.3 21.1 ----- ----- 15.2 0.4 142.0 3.6 90.3 2.3 52.7 1.3 5.5 0.1 1.2 ----- 0.4 ----- 0.1 ----- <0.1 ----- 1.1 ----- 0.5 ----- 0.2 ----- 0.1 ----- 0.7 ----- 1.7 -----

12. 12 Power Deposition and Radiation Dose in SC1 Coil The max. energy deposition at the SC1 coil is 10 -8 GeV/g per incident proton. So the max. power deposition per kg at SC1 coil is 4W/kg. 10 -8 *(10 9 )*(1.6*10 -19 )* 2.5*10 15 * 10 3 =4 W/kg The average power per kg is 0.46 W/kg. (22.1 kW, 4.8*10 4 kg) 1yr=2*10 7 s and 1Gy=1J/kg. The max. and average radiation dose per year in SC1 coil is 8*10 7 (Grays/2*10 7 s) and 9.2*10 6 (Grays/2*10 7 s), respectively.

13. 13 Lifetime of SC1 Coil SC coil in Study II (Table 3.4) : (http://www.cap.bnl.gov/mumu/studyii/final_draft/chapter-3/chapter-3.pdf)http://www.cap.bnl.gov/mumu/studyii/final_draft/chapter-3/chapter-3.pdf Compone nt Dose/yr (Grays/2*10 7 s) Max allowed Dose (Grays) 1 MW Life (years) 4 MW Life (years) SC coil6*10 6 10 8 164 Max allowed Dose (see Al Zeller, Radiation Issues in Capture Solenoid) (http://www.fnal.gov/projects/muon_collider/nu-factory/subsys/ss- target/scan3.pdf)http://www.fnal.gov/projects/muon_collider/nu-factory/subsys/ss- target/scan3.pdf Evaluation of life time for SC1 coil: Compone nt Dose/yr (Grays/2*10 7 s) Max allowed Dose (Grays) 1 MW Life (years) 4 MW Life (years) SC1 coil (max) 8*10 7 10 8 1.250.3 SC1 coil (ave) 9.2*10 6 10 8 10.82.7

14. 14 Enhanced Shield for SC Coils (WC shield is extended from R=50 to R=63 cm.)

15. 15 Energy Deposition in SC coils (4MW beam, enhanced shield) Regional Name ED [GeV]P [kW]P/P beam [%] SC11.199*10 -2 4.80.12 SC29.04*10 -4 0.360.01 SC36.7*10 -4 0.270.01 SC42.18*10 -4 0.090.002 SC51.34*10 -4 0.050.001 SC61.51*10 -4 0.060.002 SC78.49*10 -3 3.400.08 SC83.61*10 -3 1.440.04 SC92.13*10 -3 0.850.02 SC101.23*10 -3 0.490.01 SC118.28*10 -4 0.330.01 SC129.5*10 -4 0.380.01 SC136.39*10 -3 2.540.06

16. 16 Enhanced Shield for SC Coils (No Res Sol, WC shield is extended from R=50 to R=63 cm.)

17. 17 Energy Deposition in SC coils (4MW beam, no Res Sol, enhanced shield) Regional Name ED [GeV]P [kW]P/P beam [%] SC13.21*10 -3 1.300.03 SC25.88*10 -4 0.240.006 SC36.53*10 -4 0.260.007 SC41.97*10 -4 0.080.002 SC51.09*10 -4 0.040.002 SC61.56*10 -4 0.060.002 SC77.95*10 -3 3.180.08 SC84.14*10 -3 1.660.04 SC92.62*10 -3 1.050.03 SC101.45*10 -3 0.580.01 SC118.53*10 -4 0.340.01 SC129.77*10 -4 0.390.01 SC136.74*10 -3 2.700.06

18. 18 Distribution of Energy Deposition (No Res Sol, WC shield is extended from R=50 to R=63 cm.)

19. 19 Summary The bulk of the 4MW beam power is deposited in the tungsten-carbide shield, Hg Jet and STST Env. Both MARS 15 and FLUKA simulations give us similar results. Power deposition and radiation dose for SC1 coil are calculated and the life time of SC1 coil is evaluated based on the Study II document. Enhanced shield can decrease the power deposition in SC1 coil from 22.1kW to 4.8kW. By replacing the Res Sol by WC shield, the power deposition in SC1 coil can be decreased further to 1.3kW.