1. Status of the new Target Design n_TOF Collaboration meeting, Paris 4-5 December 2006 P. Cennini AB-ATB Status of the old Target Removal Status of the old Target Removal New target design New target design

2. Old Target Removal Shielding removal: done. Shielding removal: done. Radioactivity measurement in the Access Pit: done. Radioactivity measurement in the Access Pit: done. Simulations of the Target Activation: done. Simulations of the Target Activation: done. Risk Analysis for he Target Removal: done. Risk Analysis for he Target Removal: done. Procedure for the Target Removal: done. Procedure for the Target Removal: done. Crane upgrade: under discussion Crane upgrade: under discussion

3. Radioactivity Measurement P. Carbonnez SC-RP

4. Old Target Removal: Actions in Progress Discussion with the suppliers for the construction of a system certified for radioactive loads: Discussion with the suppliers for the construction of a system certified for radioactive loads: expected cost 300 kCHF, expected delivery May 2007. Discussion on the possibility to use the existing crane after implementations of the infrastructures required for the recovery of the Target in case of heavy failure stopping the operation. Discussion on the possibility to use the existing crane after implementations of the infrastructures required for the recovery of the Target in case of heavy failure stopping the operation. More information on the procedures: https://edms.cern.ch/cedar/plsql/cedarw.site_home 774982 v.1 n_TOF Target removal and Inspection 787079 v.1 Proposal of a Procedure for the recovery of the old Irradiated n_TOF Target in case of jamming of the crane.

5. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET

6. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET xz-squared target (40x40x55 cm) centerd on the beam axis 55cm 40cm p beam Side view Front view 5 cm thick moderator container

7. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET xz-squared target (40x40x55 cm) lowered to respect to the beam axis 55cm 40cm Side viewFront view 5 cm thick moderator container p beam

8. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET

9. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET

10. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET With varying the thickness of the moderator container, 5 cm seems ideal also for D 2 O.

11. Lead Target Simulations K. Tzolou, V. Vlachoudis ATB-EET The expected neutron flux with a geometry of 40x40x55cm is the following: The expected neutron flux with a geometry of 40x40x55cm is the following: Front (center):Low energy ~80% Nominal High energy >95% Nominal Top (lowest): Low energy 68x Nominal High energy 85xNominal  The moderator container of 5 cm is the good compromise for H 2 O and D 2 O.

12. Target Design Specification  Target material: lead  Target cladding: aluminum alloy  Target cooling: water (existing system)  Target dimension: ~ 100 liters, ~1.3 tons  Moderation: water/heavy water, exchangeable during the run  Useful n-beam diameter at the exit of the target: 40 cm  n-beam losses (versus old configuration): 20% at low E, 5% at high E  Orthogonal flight-path: foreseen  Minimization of the 2.2 MeV  flash: optimized  Installation of the new target and moderator exchange: via the shaft  Hoist system: same functionality of the existing one

13. Target Design This Design is based on two principles: This Design is based on two principles: Fine positioning of the Target-Moderator assembly made with a new guiding system. Fine positioning of the Target-Moderator assembly made with a new guiding system. (Displacement in the beam direction needed to remove the cooling water after the Moderator ~ 2 cm). Replacement of the liquid Moderator made with a “Robot” lifted in place through the shaft on top of the Target. Replacement of the liquid Moderator made with a “Robot” lifted in place through the shaft on top of the Target. By using the functionality of the robot, the following goals are achieved: By using the functionality of the robot, the following goals are achieved:  Moderator exchange during the run.  All the operations remotely controlled from the Service Gallery through the shaft. The important aspect of this solution is the remote handling of all radioactive or contaminated elements reducing practically to zero the dose received by the operators to exchange the moderator in agreement with the ALARA principle.