An environment is described in which multiple companies can securely collaborate on a design or other project. The waveguide has a non-rectilinear optical path between the first and second end, the attenuation zone extends from the upper face to the lower face, and is positioned on a straight line segment joining the first and second end of the optical waveguide, the waveguide and the attenuation zone having respective dimensions such that the attenuation zone does not cut the waveguide. The magnetic member of each of the chargers has a magnetic pole facing the image bearing member. The support member is made of graphite and includes a housing accommodating a neutron emission module, a casing covering the shielded container, the casing being made of graphite, and a neutron measurement mechanism fastened to the casing. In another embodiment, a current generator is provided to generate a counter-current intended to cancel the analytically predicted level of axial current induced in the drillstring as a result of rotation in the Earth’s magnetic field.