Geophysical Centre in Dourbes

Magnetically shielded room (MSR) for archaeo- and palaeomagnetic applications

The MSR consists of an outer shield made of a double layer of electrical steel (2 x 1 mm) and an inner shield made of a single layer of mu-metal. It is aligned exactly in east-west direction. The dimension of the inner usable space are 6.6 x 3.6 x 2.4 m (length, width, height).

1. Building to house the magnetically shielded room (MSR) at the RMI's Geophysical Centre in Dourbes.

2. Delivery of construction materials: beams for the wooden frame.

3. Outlining the emplacement of the MSR.

4. Mapping the ambient magnetic field before construction.

5. Electrical steel for the outer shield is delivered. ;-) But cleaning road needs to be done first, before getting it inside the building! ;-)

6. Carpenter’s work; cutting wooden beams for the frame.

7. Mounting the frame of the floor.

8. Floor frame mounted.

9. Assembly of the floor outer shield.

10. Ready for mounting the frames of the side walls.

11. Mounting the remaining parts of the frame.

12. The wooden frame is ready! ;-) But the few extra support boards have to come off again! ;-)

13. Preliminary anhystertic remanent magnetisation (ARM) of the outer shield ceiling panels.

14. Mounting the outer shield ceiling panels.

Anysteretic remanent magnetisation - magnetically shielded room (MSR) — 15. Preliminary magnetisation (ARM) of the outer shield side panels.

16. Mounting the side panels of the outer shield.

Magnetic equilibration - magnetically shielded room (MS) — 17. Magnetisation (ARM) of the outer shield side walls on the north wall after installation.

Magnetically shielded room (MSR) - electrical steel — 18. View into the MSR after the outer shield has been completed.

19. Preparation of the MSR for the installation of the inner shield: Mounting of OSB intermediate panels.

20. The MSR is now ready for mounting the inner shield made of mu-metal, i.e. a ferromagnetically soft alloy consisting mainly of nickel and iron.

21a: Mounting the first mu-metal panels.

21b: Mounting mu-metal panels.

Magnetically shielded room (MSR) - mu-metal — 22. Fitting the ceiling panels of the inner shield is somewhat tricky, isn't it?

Magnetically shielded room (MSR) - mu-metal — 23. Finally done with the mu-metal.

24. A first test: shielding works better than expected! :-) 122 nT at this point, approximately in the centre of the MSR!!!

Construction of a magnetically shielded room (MSR) — 25. Mounting the final inner side walls made of OSB panels.

26. Mounting the final floor of the MSR. ;-) Don't worry, the screws are only temporary. ;-)

27. :-) Ha, what’s that??? The inmost ward of our MSR, to preserve some contemporary witnesses. Hopefully their "relaxation time" is long enough! :-)

28. 5th of June 2025: Almost done! The RMI's Director-General congratulates us on the success!

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