nTOF Target 3 Physics performances nTOF Target3 Review

n_TOF Target #3 Physics performances n_TOF Target#3 Review CERN Nov 6 2018 Vasilis. Vlachoudis@cern. ch Francisco. Ogallar. Ruiz@cern. ch and the n. TOF Target#3 WG

Introduction General remarks • All presented solutions are for the up to date geometry as it is presented in previous talks. • All performances are for the EARx unless it is indicated differently • The results will present the current status of the solution #5 • The more “realistic” it becomes a target, the performances degrade Main updates • Include new moderator shape (not completely circular). • Include anticreep structure, but not the last version with only one layer of 4 mm Al between slices and more vertical strips. • Do not include the aluminum strips of the moderators structure yet.

Solution #5 May Review Solution under development, so far: § Good perspectives from physics point of view. § The target itself seems simple in terms of manufacturing. § Would require a new gas cooling station (also Solution #4).

Solution #5 May Review: Performances EAR 1 EAR 2

Solution #5 May Review: Performances EAR 1 prompt EAR 1 delayed

Solution #5 May Review: Performances x 6 e s crea n i Big EAR 2 prompt EAR 2 delayed

Solution #5: Introduction of Pb shielding block 28 mm gap Including a Pb block to reduce γ-flash in EAR 2 Pictures from Vincent Maire

Sol #5: Neutron Fluence ≤ x 2 Noticeable the effect of B-H 2 O EAR 1 EAR 2 8

Sol #5: Delayed γ fluence ≈1/10 ≈1/2. 5 EAR 1 EAR 2 9

Sol #5: Prompt γ fluence ≤ x 2 EAR 1 EAR 2 10

Sol #5: Resolution Function in EAR 1 1 to 10 e. V 1 to 10 ke. V 1 to 10 Me. V 11

Sol #5: Resolution Function in EAR 2 1 to 10 e. V 1 to 10 ke. V 1 to 10 Me. V 12

Sol #5: Neutron Fluence Comparison: current target, Sol #5 with borated water vs normal water as moderator. EAR 1 EAR 2 13

Sol #5: Delayed γ fluence Comparison: current target, Sol #5 with borated water vs normal water as moderator. EAR 1 EAR 2 14

Sol #5: Prompt γ fluence Comparison: current target, Sol #5 with borated water vs normal water as moderator. EAR 1 EAR 2 15

Sol #5: ~Variation wrt Solution #0 [%] Comparison: current target, Sol #5 with borated water vs normal water as moderator. EAR 1 EAR 2 Sol 5_BW Sol 5_NW Neutron flux -28 +587 -87 +4 Neutron flux (1 e. V… 100 e. V) -7 +15 -12 +12 Neutron flux (100 e. V… 10 ke. V) +1. 4 +4 +17 +25 Neutron flux (10 ke. V… 1 Me. V) +10 +9 +85 +91 Neutron flux +4 +2 +103 +104 Prompt photons flux -2 -2 +43 +55 Delayed photons flux -59 +366 -92 -7 (0. 01 e. V… 1 e. V) (1 Me. V… 100 Me. V) (Above 1 Me. V) BW: Borated Water NW: Normal Water 16

Conclusions • • It fulfills all requirements expressed by the n_TOF collaboration Sol #5 exhibits similar performances wrt present target in terms of neutron flux for both areas. Better RF for EAR 2, similar RF for EAR 1 Better delayed g background for EAR 1 & 2 Increase of × 2 in the EAR 2 evaporation region is observed thanks to the better vacuum chamber design (not the target) Warning: delayed g background produced on the 2 nd collimator will be increased proportionally Borated water in EAR 2, depletes thermal peak. Sol #5 will accept higher proton intensity bunches up to 1013 p+ 30% increase wrt the present one, but still the same average power on target; therefore the 1. 66 1012 p/s limitation will still apply.