Atomic and nuclear physics - Frederiksen

122Atomic and nuclear physicsRadioactive sourcesRadioactive sourcesSealed radioactive sources for education, consisting of thealpha, beta and gamma sources described below.Each source consists of a Plexiglas handle with a threadedaluminium sleeve at the active end.The sources are ISO classified as ISO/99/C11111 and havepassed ISO 9978 contamination and leakage tests.The set includes the 5100.40 storage holder.5100.00 Radioactive sources, set with holder5100.00Alpha sourceThe isotope used is americium-241 (activity: 37 kBq, half life:458 years). Americium-241 decays to neptunium-237 by alphadecay, accompanied by some gamma radiation.The radioactive material is mounted in an approved holder witha Plexiglas shaft threaded at one end for mounting in a support.5100.10 Alpha sourceBeta sourceThe isotope used is strontium-90 (activity: 37 kBq, half life:28 years). Strontium-90 decays by beta decay throughyttrium-90 to zirconium-90. This source emits virtually nogamma radiation. The radioactive source is mounted in anapproved holder with a Plexiglas shaft threaded at one end formounting in a support.5100.20 Beta sourceGamma sourceThe isotope used is cesium-137 (activity: 370 kBq, half life:30 years). Cesium-137 beta decays to an excited state ofbarium-137, followed by a gamma decay to the ground stateof barium-137. The mechanical construction of the sourceensures that most of the beta radiation is absorbed inside thesource, leaving only the gamma rays to penetrate the enclosure.The radioactive source is mounted in an approved holder with aPlexiglas shaft threaded at one end for mounting in a support.5100.30 Gamma sourceStorage holderThis Plexiglas holder is convenient for storage of three sources.5100.40 Storage holderCobalt-60 source (gamma)The isotope Co-60 (initial activity: 260 kBq, half life: 5.27 years)beta decays to an excited state in nickel-60. The beta decay isfollowed by a cascade of two gamma decays. The mechanicalconstruction of the source ensures that most of the beta radiationis absorbed inside the source – although a tiny fraction willleave. The highly energetic gamma rays have no problems withpenetrating the enclosure.The radioactive source is mounted in an approved holder witha Plexiglas shaft threaded at one end for mounting in a support.5100.35 Co-60 source (gamma)Sodium-22 source (positrons)5100.35The isotope Na-22 (initial activity: 240 kBq, half life: 2.60 years)is a beta-plus emitter – i.e. positrons are released from thenucleus. When positrons and electron annihilate, two gammaquanta are produced. The daughter nuclide (Ne-22) also emitsgamma radiation.Unlike many other Na-22 sources, a large fraction of the positronsare able to escape the sealed enclosure of this source.This enables you to study the properties of these elementaryparticles. The radioactive source is mounted in an approvedholder with a Plexiglas shaft threaded at one end for mountingin a support.5100.37 Na-22 source (positrons)®science