Bollen G, Davies D, Facina M, Huikari J, Kwan E, Lofy P A, Morrissey D J, Prinke A, Ringle R, Savory J, Schury P, Schwarz S, Sumithrarachchi C, Sun T, Weissman L
National Superconducting Cyclotron Laboratory. Michigan State University, East Lansing, Michigan, USA.
Phys Rev Lett. 2006 Apr 21;96(15):152501. doi: 10.1103/PhysRevLett.96.152501. Epub 2006 Apr 19.
The mass of the short-lived radio nuclide 38Ca (T(1/2) = 440 ms) has been measured with the 9.4-T Penning trap mass spectrometer of the Low-Energy Beam and Ion Trap Facility. A mass uncertainty of deltam = 280 eV has been achieved, corresponding to deltam/m = 8 x 10(-9). The result makes 38Ca, a superallowed beta emitter, a new candidate to test the conserved-vector-current hypothesis. The experiment is also the first demonstration that short-lived radioactive isotopes produced by projectile fragmentation of relativistic heavy-ion beams can be slowed down and prepared such that precision experiments of this kind are possible.
利用低能束流与离子阱装置的9.4特斯拉彭宁阱质谱仪测量了短寿命放射性核素38Ca（半衰期T(1/2)=440毫秒）的质量。实现了280电子伏特的质量不确定度，对应于相对质量不确定度deltam/m = 8×10^(-9)。该结果使超允许β发射体38Ca成为检验守恒矢量流假设的新候选者。该实验也是首次证明，相对论重离子束弹丸碎裂产生的短寿命放射性同位素能够被减速并制备出来，从而使得此类精密实验成为可能。
