1. https://indico.cern.ch/event/807540/
n_TOF Target #3 Production Readiness Review History of Target #3 options and baselining
M. Calviani (EN-STI)
n_TOF Target #3 Project Leader
29th May 2019
EDMS

2. M. Calviani - n_TOF Target #3 PRR Introduction - EDMS 2158302
Outline
Summary of Target #3 design solutions
Path towards the definition of the Target baseline
Intermediate Engineering Design Review and follow-up
Challenges and decision to focus on N2-cooled sliced Pb target
Engineering Design Document and Project Costs
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

3. Summary of Target #3 design evolution
Over the course of the Project history, 5 design solutions have been identified and studies with a certain degree of details
Sol4
Ti64-contained Pb core, ext. Pb mass
Sol5
sliced Pb core, N2 cooled
Sol3
Ta-cladded W core, ext. Pb mass
Sol1
Bare Pb core
Sol2
Ti64-contained Pb core Pb W Pb
Ti-Pb Pb
Ti-6Al-4V Pb Pb
Discarded after PDR
Discarded after PDR
Baseline at IEDR
Later discarded
Baseline at PRR
Backup at IEDR
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

4. Solution #2 (core and vessel)
Solution 2: water-cooled Ti-6Al-4V-cladded Pb core (monolithic)
Solution discarded due to physics (Be stiffener reducing flux in EAR1) and technological reasons (complex to maintain good thermal contact)
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

5. Solution #4 (core and vessel)
Solution 4: water-cooled Ti64-cladded Pb core, embedded in an “air” cooled external Pb mass for physics reasons
Solution judged sound by IEDR reviewers but quite complex to implement technically with significant reliability risks
Complex mechanical assembly, cantilever core, complex N2 circulation in external mass
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

6. M. Calviani - n_TOF Target #3 PRR Introduction - EDMS 2158302
Solution #5
Solution 5: N2-cooled Pb sliced target
Technologically innovative, but appears the most appealing from a physics as well as technological perspective
Operational simplification: no high-Z contaminated H2O, no ion-exchangers, etc.
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

7. NEW Target options at IEDR
Solution 4 Ti64-contained pure Pb, water cooled, contained in a N2-cooled mass
Solution 5
N2-cooled pure Pb slices
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

8. IEDR analysis of recommendations and follow-up
Reviewers have highlighted the excellent quality of the presentations and work done, feedback provided in EDMS
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

9. Project decision post IEDR & path towards IDR
“Avoid unnecessary complexity”  remove mechanical complexity from the target pit and eventually move it out
Re-optimization on physics performances for the target, balancing requirements from n_TOF Collaboration on EAR1 and EAR2
Focus on “neutron/gamma background” rather than on increasing power on target
Contrary to previous requirements, the baseline was changed to keep the current average protons on target – 1.7*1012 p/s , maximizing the pulse intensity if feasible
No manpower and budget to follow more than 1 solution  need to baseline
Dedicate resources on the study and development of a nitrogen cooling station adapted to the Project needs
Push in order to execute HiRadMat beam tests of both Solution #4 and #5 (October 2018) and a timely PIE on Solution #5
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

10. M. Calviani - n_TOF Target #3 PRR Introduction - EDMS 2158302
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

11. Project decision post IEDR & path towards IDR
Taking into account all pertinent factors the Project decided to:
Go ahead with the detailed design and assessment of open points on the nitrogen cooled sliced Pb target (Solution #5) – baseline target
Simplification of mechanical complexity in the target pit (inaccessible after installation)
Stopping further developments of Solution #4 (Ti64- cladded Pb) given the complexity of the assembly and technical requirements similar to those of Solution #5
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

12. Solution #5 IEDR suggestions
From the review document (EDMS ):
Further study and define anti-creep geometry [required] in order to improve cooling even in case Pb creeping leads to clogging
Assess the target assembly rigidity to limit vibrations and their consequences
Optimize the cooling system and parameters (N2 flow rate and velocity in critical regions) as trade-off between cooling efficiency and induced vibrations or pressure losses
Take into account nitrogen chemistry risks
Reduce photon and high energy neutron streaming to experimental areas by using an additional lead wedge or tilted anti-creep plates, as proposed immediately after the review
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

13. Project decision post IEDR & path towards IDR
From July 2018 to November 2018 all Project resources dedicated to address the open points of Solution #5 highlighted by the IEDR
Project organized an Internal Design Review (IDR) on 6th November in order to check the status
No showstopper identified, leading to the
go ahead for the detailed studies of the (now) baseline design (Solution #5)
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

14. n_TOF Collaboration feedback
Baseline target design was presented to the n_TOF Collaboration at the Board meeting on 29th November 2019
Proposal was endorsed by the Collaboration Board
Collaboration however requested a separated moderator circuit (EAR1 vs. EAR2)
V. Vlachoudis
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

15. Engineering Design Document
A detailed design document has been prepared in order to summarize the design choices, studies, simulation, prototyping and beam tests
Coverage of most of the aspects discussed at this review
TOF-TAR-ES-0003 (EDMS ), linked to the INDICO page
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

16. Information of Project costs
The Target #3 Project is fully financed by Accelerator Consolidation Project (ACC-CONS)
Originally foreseen budget (~2014) was around 600 kCHF
Current the Project is financed for a total 1.7 MCHF (M+P)
Excluding costs for additional moderator (covered by the Collaboration) & other beam line related aspects, which will be covered by the STI n_TOF operational budget
TOF-PM-MG-0002 (EDMS ) is detailing the different budget sources – all looks ok at the moment
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

17. M. Calviani - n_TOF Target #3 PRR Introduction - EDMS 2158302
Focus of the PRR
In the last 6 months, Solution #5 (N2-cooled sliced Pb target) has been thoroughly analyzed, addressing most of the recommendation and suggestions from IEDR/IDR as well as actions from Project meetings
Extensive CFD, including optimization of anti-creep plates (R. Ximenes)
Thermo-mechanical simulations with coupled & sensitivity studies (R. Esposito)
Summary of target vibration studies by external partner (R. Esposito)
Detailed studies of the N2-cooling station (F. Dragoni)
Significant prototyping to address feasibility (& costs) (M. Timmins)
Beam irradiation tests (R. Esposito)
The Project believes that this is a mature solution and ready to be built and operated
22 May 2019
M. Calviani - n_TOF Target #3 PRR Introduction - EDMS

18. Thanks a lot