Tungsten target tests at the ISIS - part II -

1. Goran Skoro Tungsten target tests at the ISIS- part II -

2. ISIS Beam Target • Dimensions • 2.5x1013 protons per pulse; • Pulse structure: • Repetition rate 50 Hz; • Beam energy = 0.8 GeV; • Beam profile: parabolic; • Beam radius = Target radius. • 1.0 cm diameter; 15 cm length • 1.5 cm diameter; 15 cm length • 100 ns • 100 ns Material: Tungsten • 230 ns • To calculate: • Energy deposition in the tungsten target -------------------- MARS • Thermal model ---------------------------------------- ANSYS • Surface displacements, accelerations, peak stresses -------- LS-DYNA • Target activation -------------------------------------- FLUKA

3. Surface accelerations, displacements, stresses … Peak stress (Neutrino Factory, 4 MW, 2cm diameter, optimised pulse length) 300 MPa~ 2x lower than here • 1 x 15 cm target • LS-DYNA • 2.5x1013 protons per pulse, parabolic beam • Surface acceleration [106 m/s2] and displacement [m] as a function of z-position for initial temperature of 300 K • Peak von Mises stress = 587 MPa • * 1.5 cm is the distance where we have a maximal surface displacement

4. Surface accelerations, displacements, stresses … Peak stress (Neutrino Factory, 4 MW, 2cm diameter, optimised pulse length) 300 MPa ~ optimal dimensions ~ • 1.5 x 15 cm target • LS-DYNA • 2.5x1013 protons per pulse, parabolic beam • Surface acceleration [106 m/s2] and displacement [m] as a function of z-position for initial temperature of 300 K • Peak von Mises stress = 287 MPa • * 1.5 cm is the distance where we have a maximal surface displacement

5. Calculations of the target activation • Status (04/12/2007): • MCNP/MCNPX • FLUKA • Copy of the code has been ordered from OECD–NEA (France); - they are not quick (4-6 weeks) - • Licensing procedure in progress; • ‘Single-site/single-user’ licence (!) • First results (next slide)

6. 10 pulses (1 hour between each two pulses) Calculations of the target activation 1 pulse Specific activity of the target [Bq/cm3] Cooling time [h] • 1.5 x 15 cm target • FLUKA • 2.5x1013 protons per pulse, energy = 0.8 GeV • 10 minutes • 1 hour • 8 hours • 1 day • 1 week • 1 month

7. Any intervention here: wait at least Tc = 1 hour after each pulse; (if Tc = 1 hour) total intervention time should not exceed 30 minutes (2 mSv criterion). A design criterion for high-radiation areas (at CERN, for example) = 2 mSv per person per intervention but must be below 20 mSv per year (category A workers) 100x higher than background rate; 7x higher than during London-Tokio flight. scenario: in contact (4); no radiation self-absorption in the target; <1 MeV>/decay; etc… 10 pulses (1 hour between each two pulses) A quick estimate of the effective dose rate 1 pulse Effective dose rate [mSv/minute] Cooling time [h] • 1.5 x 15 cm target • 2.5x1013 protons per pulse, energy = 0.8 GeV • 10 minutes • 1 hour • 8 hours • 1 day • 1 week • 1 month