41. Polonium alloyed with beryllium provides an efficient neutron source. 42. Several studies have shown that there is a genetic component to beryllium sensitivity. 43. Establishing beryllium sensitivity is the first step in diagnosis. 44. Although the evidence that stopping exposure to beryllium decreases progression of the disease, 45. A typical neutron probe contains a pellet of americium-241 and beryllium . 46. In the vapour phase, beryllium oxide is present as discrete diatomic molecules. 47. It is readily hydrolysed forming beryllium hydroxide and ammonia. 48. A thick beryllium reflector ( ~ 10 cm ) surrounds the core radially. 49. Specializes in flat ( plano ) metal ( aluminum & beryllium ) optics. 50. The most effective moderating nuclei are hydrogen, deuterium, beryllium and carbon.