protect personnel from these penetrating rays

To protect personnel from these penetrating rays, thick, dense material (e.g., lead, steel, etc.) is used as shielding. Certain analytical systems, (e.g., x ray diffraction), have sufficient voltage to produce low energy (e.g., 1 50 keV) or soft x rays. The soft x rays with energies from 1 to 20 keV are absorbed in the first few millimeters of the skin, although for extremities, some of this radiation may also be absorbed to the bone.