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J-PARC neutrino experiment Target Specification

J-PARC neutrino experiment Target Specification. A.K.Ichikawa 15 th May 2003. Graphite or Carbon-Carbon composite cylindrical bar : length 900mm, diameter 25~30mm The bar may be divided into several pieces. The stress generated in the target is proportional to

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J-PARC neutrino experiment Target Specification

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  1. J-PARC neutrino experimentTarget Specification A.K.Ichikawa 15th May 2003 • Graphite or Carbon-Carbon composite • cylindrical bar : length 900mm, diameter 25~30mm • The bar may be divided into several pieces. • The stress generated in the target is proportional to • EaDT • where E: Yang’s modulus, a : linear coefficient of thermal expansion, • DT : temperature rise. • So, we want a material which has high S/Ea where S is the yield • strength. • The quantities we concern are • r(density), E, a, S(yield and compression strength) • and resistivity against radiation.

  2. R&D of Target and Horns are in progress by Neutrino construction group and Target&Monitor group in KEK. Especially, Target by Y. Hayato with KEK Target&Monitor group lead by Noumi Horns Conceptual design by A. K. Ichikawa supported by Y. Yamanoi, Y. Suzuki and Target&Monitor group

  3. Target for K2K 12kJ in 1.1ms Al 30mmf x 660mm (Embedded in the horn) Heat was generated by the horn-current Target for J-Parc 2.6MJ in 5ms Aluminum cannot withstand. Only low-Z material such as graphite or beryllium.

  4. J/gK degree R Z Graphite w/ water cooling Density ~1.8g/cm3 Melting point ~3600oC Good thermal conductivity Mechanically strong Temperature rise due to the radiation cal. w/ MARS w/ 1 pulse

  5. Target Size • Pion absorption • Temperature rise • Energy concentration • Inner radius of the horn • Beam size ~1cm

  6. Currently, 25mmf~30mmf is being considered.

  7. r=0mm,z=300mm r=15mm,z=300mm (Sec.) 12 32 4 8 Time dependence of temperature DTmax ~200oC at center ~40oC (Thermal convection coefficient on the surface should be larger than to satisfy <100oC@surface condition.) by Y. Hayato and M. Minakawa

  8. Cooling test T.Oyabu et al. Heat load by electric current Current (~1300A) Cooling water Cooling w/ surrounding water.

  9. flow : 0.83m/sec C03 C01 C10 C02 C11 C01 Temp. at the surface of the target C02Water temperature C03Temp. at the center of the target C10Water temperature (out) C11 Water temperature (in) Temp. Heat convection coefficient btw. graphite and water was measured at various conditions. Time (min.)

  10. Cooling Test w/ more realistic setups By Y. Hayato

  11. By A. K. Ichikawa

  12. Calculation by hand squasi-static = 10~15MPa sdynamical = ~8Mpa Safety factor ~3 Stress analysis using FEM just started. Thermal stress by Y. Hayato

  13. Example of Possible itemsexpected to Foreign Institute This is not a perfect list. More discussion is necessary. Target : Material itself (graphite w/ good mechanical property, C-C composit, etc.) Measurement of quality(strength, radiation resistivity, heat conduction etc.) of materials Horns : Independent stress analysis Production of inner conductor

  14. Summary Target Base line of the current design is graphite of 25~30mmf surrounded by cooling water In this year, cooling test and examination of various items such as mechanical stress calculation and cooling schemes will be conducted. Horns Base line of the current design is 3 horns with 320kA current. In this year, conceptual design will be completed and examination of various items such as mechanical stress, cooling and power supply will be conducted.

  15. Heat Load from Radiation R Z Inner cond. Al t=4mm Air t=6mm 30mmf Water t=5mm Graphite r=1.8g/cm3 60mmf In the graphite target, 64kJ/3.3E14 protons in total R Z Dt~14o In total, 34kJ/3.3E14 protons = 10 kW @ 0.3Hz cf. K2K heat load in the target from the current = 1.4 kW (surface area ~x 7)

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