The instrument B8 allows to irradiate and activate artistic, technical, or geological items (foils, stones etc.) and other materials with cold neutrons and to investigate it afterwards with imaging plate technique and/or to analyse it with gamma-spectroscopy. The painting is fixed on a support in front of a neutron guide end with an open area of 3.5 x12.5 cm2. The surface of the painting is adjusted under a small angle (< 3° ) with respect to the axis of the guide so that the main free path of the neutrons within the paint layer is much longer than in the case of perpendicular transmission. The support is moved up and down with a velocity of a few cm/s in order to receive a uniform activation of the total area of the panel.
On a special table in a shielded room in the basement the film exposure and the gamma spectroscopy can be performed for the suitable times (up to more than 4 weeks) depending on the half-lives of the isotopes.
Advantages of the method:
- Activation cross-section (n,β) depends on the isotope
- Different pictures depending on the half-lifetimes of the isotopes
- Less γ-rays (cold source)