Installation of Neutron Beam Port Inserts and Plugs under way

First NBPP
The first Neutron Beam Port Plug is pushed into one of the port tubes surrounding the Target Monolith. Image: Ulrika Hammarlund/ESS

International collaboration was key as ESS reached an important milestone with the start of installation of Neutron Beam Port Inserts and Plugs last week.

ESS instrument suite -south sector marked

ESS instrument layout. The installation of inserts and plugs started in the south sector, marked with a red circle.

The inserts and plugs constitute the first interface between the ESS target systems and the neutron instruments, as the inserts also contain the first part of the neutron optics, provided and integrated by the Neutron Scattering Systems.

The design of the Neutron Beam Port Inserts and Plugs was developed by German in-kind partner Forschungszentrum Jülich (FZJ) in collaboration with the ESS Target Division. Manufacturing was done by Fantini in Italy and neutron guide integration performed on the ESS site by Swiss Neutronics and S-DH, Germany.

The installation of the Neutron Beam Port Inserts and Plugs started on 23 February 2023, as the very first plug was inserted into beam port S1 in the south sector. This will be followed by two more plugs, and then the two inserts for instruments ODIN and DREAM.

Ultimately, there will be 16 inserts for the 15 planned instruments and the Test Beamline, with the rest of the port tubes equipped with plugs.

See this short movie of the successful installation of the first plug and neutron beam window, using a specially designed installation tool.

Filmed and edited by: Ulrika Hammarlund/ESS

Installation of the lower and upper pancake shielding blocks to the Monolith vessel.

Filmed by: Krister Blomberg/ESS   
Edited by: Ulrika Hammarlund/ESS

The inserts and plugs are installed into the port tubes, which are welded to the Monolith vessel. A prerequisite for the installation to start was that the two pancake cooling blocks were in place inside the vessel, as they contain slits into which the inserts and plugs are placed. This installation was completed on 22 February.

The inserts contain neutron optics that will guide the moderated neutrons on the very first part of their journey towards the sample position of each instrument. Plugs – massive steel chunks – are installed into the port tubes currently not occupied by an instrument.

Target Station with 42 beam ports

Schematic view of the Target and the 42 beam ports.

Neutron Beam Window

First neutron beam window at ESS.

Each insert and plug is then equipped with a neutron beam window (see image to the right), which seals the Monolith atmosphere from the instrument beamlines. They also have an internal window made of aluminium through which the neutrons can pass. Only the inserts that contain optical guides will let through neutrons to the instruments, and these windows also contain a media connector. The neutron beam windows are a delivery of Nortemecanica, Spain.

Ongoing work and next steps

Twelve out of the total 16 inserts have been delivered to ESS, with the last four arriving during the spring. Upon delivery, the inserts are set up in an on-site integration tent, where optics assembly, alignment and vacuum tests take place.

All 26 plugs have been delivered and checked and are ready for installation.

NBPP test installation Naja

Naja de la Cour, Work Unit Lead for the inserts and plugs, at a test installation of a plug last summer.

The installation on site of the first plug was performed by the Target design group, under supervision of the Target installation team who will be responsible for the remaining installation of plugs and inserts.

ODIN neutron guide

Assembly and alignment of the optics inside the inserts is performed in an on-site integration tent. This insert is for ODIN.

Once installation of eight plugs and two inserts is completed in the south sector, works will continue in the east, north and west sectors, until all 42 port tubes have been equipped with a plug or insert.

The installation of inserts and plugs will pave the way for in-bunker installations to continue for all instruments at ESS.