Overview of the TARGET Monolith Rough Vacuum Dr. Marcelo juni Ferreira ESS Vacuum Section Leader European Spallation Source ERIC 28/05/2019

Outline Background of ESS monolith solution, Introduction to ESS Vacuum System, Vacuum Standardization Vacuum requirements: TARGET Monolith Rough Vacuum System specifications and interfaces,

ESS Monolith Vacuum System Brief history April/2014 First discussion with Target Div. about the He and Vacuum specifications, for big vessels and possibilities to run in He. Dec/2014 Considerations for the elimination of the Proton Beam Window, Feb/Mar 2015 Detailed discussions on the PBW elimination, Nov/2015 PDR for the Monolith vessel made clear: He and Vacuum solution present the same ”cleaning” requirements, what translate in following ”vacuum standards” for fabrication (welding, cleaning, leak rates…), PBW shall be persuade in any solution + He is possible solution as SNS, the monolith vessel shall follow pressure code. Dec/2015 to April/2017 Evolution of the vacuum and He solutions as possible. Details discussions for vacuum fabrication and design. April/2017 Final decision to persuade only vacuum solution. Fabrication following high vacuum standards, operation rough vacuum (a part discussion for Beam Instrumentation). Feb/2019 Formal responsibility transfer of the Monolith Rough Vacuum System to the ESS Vacuum Section. May/2019 Monolith Rough Vacuum CDR (alignment of scope for Vacuum Section responsibilities)

Introduction Target tank diameter 6 m x 9m Warm LINAC Cold LINAC Accelerator ≈ 600 m Neutron Instruments Neutron Instruments ≈ 120 m/each Total = 22 x 120 ≈ 2240 m The ESS organization charges the ESS Vacuum Section (VS) with the responsibility for all ESS vacuum systems including not only the Accelerator, but also Instruments, Neutron Beam Lines and the Target. The main task of the ESS VS is to support the in kind contributions on the vacuum system and the integrated vacuum design of the ESS complex.

Vacuum Standardization, an Integrated Approach Working closely with our partners across the project one of our primary goals was to promote the use of common vacuum equipment and standards. As a result a Vacuum Standardization meeting was held in February 2014 where equipment suitable for Standardization was agreed and reflected in the ESS Vacuum Handbook. An important element of this Standardization is the Procurement Policy applied for the procurement of all “major” vacuum equipment. This policy ask the partners to participate on a single Framework Agreement, The ESS Vacuum documents (handbooks, rules or interfaces documents) are the majors documents that covers the requirements for the accelerator, target and instruments and is applicable to all ESS IKC Partners . For the Monolith Vessel the document is the ESS-0057844 ESS Monolith Vessel Vacuum Rules.

Vacuum Requirements: Target 3D model for vacuum simulation Proton beam window Moderator and reflector plug Target wheel Neutron beam extraction Target drive housing Neutron beam window

Applicable regulations, codes and standards ✓ OK! ✓ OK! ✓ OK! Not usual requirement for vacuum system. Extra cost! ✓ OK! Not usual requirement for vacuum system. Extra cost!

Safety related requirement ✓ OK! Not usual requirement for vacuum system. Extra cost!

Performance requirements ✓ OK! Not usual requirement for vacuum system. Extra cost!

Performance requirements ✓ OK!

Performance requirements ✓ OK!

Performance requirements Extremely dependent of each component condition, venting process and leaks. ✓ OK!

Performance requirements Extremely dependent of each component condition and leaks. Upgrades are limited by mechanical constrains (pipe and flange conductance). Lessons learned from SNS. ✓ OK!

Requirements related to instrumentation, monitoring and controlance requirements ✓ OK!

Requirements related to instrumentation, monitoring and controlance requirements ✓ OK! ✓ OK!

Requirements related to instrumentation, monitoring and controlance requirements ✓ OK!

Requirements related to instrumentation, monitoring and controlance requirements ✓ OK! ESS Vacuum team has a calibration system on the VacLab. ✓ OK! It will require a specific system to sample the gas.

Constraints related to building interfaces and location within the target station ✓ OK! ✓ OK! Some discussion necessary, space required bigger than the original plan.

Constraints related to building interfaces and location within the target station ✓ OK!

Requirements on infra-structural ✓ OK! ✓ OK!

Requirement on vacuum pumps ✓ OK! Worst case scenario at maximum power.

Requirements on valves ✓ OK! ✓ OK! EPDM gaskets rated for 1 MGy.

Requirements on pressure measuring equipment ✓ OK! Vacuum instrumentation rated for UHV/baking full metal.

Requirements related to redundancy, separation and functional diversification ✓ OK! ✓ OK!

Material constraints ✓ OK!

Pressure/leak testing ✓ OK!

Installation logistics Extremely dependent on all/each component scheduling and limited by mechanical constrains (access to cranes and clean areas) ✓ OK!

System and components performance testing ✓ OK! Vacuum equipment are standardized and already approved. ✓ OK! All Vacuum components need to pass Acceptance test as on the ESS Monolith Vacuum Rules.

Missing interfaces ICD-R Monolith Rough Vacuum System and Proton beam Window. Define PBW total inflatable seal leak rate: 5 x 10-4 mbar.l/s The adding of this requirement has no impact on the Monolith Vacuum System solution! Requirement on water Create the interface for cooling water on the Turbo pumps for the MRV. Discussing started with some impact on the system available and pipe routing through the wall penetrations to the monolith room.

Target Vacuum requirements (major ideas as originally discussed) Moderator and Reflector Plug The vacuum levels for insulating vacuum of the moderator and reflector plug will be in the 10-2 to 10-3 Pa range, although lower levels will be required in the preparation of the hydrogen services lines to prevent the build up of condensable gases. Monolith The monolith will be required to operate in either a helium or vacuum environment. To operate in a high purity helium (ambient pressure) using a Proton Beam Window (PBW) environment pump and purge to 1 Pa range will be needed and leak rate (air or water from cooling system on the shield blocks) compatible com HV, In the vacuum mode a pressure in the 10-3 mbar range will be required for interfacing with the HEBT of the accelerator without PBW to limit the flow of gas from the monolith into the accelerator.

Thank you! Tack!