A time-of-flight correction procedure for fast-timing data of recoils with varying implantation positions at a spectrometer focal plane-猫眼课题宝

DOI：

10.1016/j.nima.2019.04.019

发表时间：

2019-07

期刊：

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

M. Mallaburn;B. S. N. Singh;D. Cullen;D. Hodge;M. Taylor;M. Giles;L. Barber;C. Nita;R. Mihai;C. Mihai;R. Mǎrginean;N. Mărginean;C. Nobs;E. Gamba;A. Bruce;C. Scholey;P. Rahkila;P. Greenlees;H. Badran;T. Grahn;O. Neuvonen;K. Auranen;F. Bisso;D. Cox;A. Herzáň;R. Julin;J. Konki;A. Lightfoot;J. Pakarinen;P. Papadakis;J. Partanen;M. Sandzelius;J. Sarén;J. Sorri;S. Stolze;J. Uusitalo;P. Regan;Z. Podolyák;S. Lalkovski;J. Smith;M. Smoleń

在分离器的焦平面处的快速定时测量可能遭受较差的定时分辨率。这是由于行进到给定探测器的光子的飞行时间（ToF）的变化，其由发射感兴趣的γ射线的反冲核的注入位置的变化引起。为了最大限度地减少这些对定时测量的影响，提出了一种通过逐个事件执行ToF校正来改善快速定时数据的方法。该方法被用来校正由八个LaBr 3探测器组成的阵列所收集的数据，这些探测器探测了空间分布的138 Gd反冲注入在RITU谱仪焦平面上的γ射线。广义质心差（GCD）的方法被用来提取一个生命周期的数据结合一个新的程序来校准时间行走。138 Gd中第一个2+态的寿命，由K π= 8−同质异能态的衰变填充，使用ToF校正的数据测量为229（24）ps，与文献值在三个标准差内一致。结果与蒙特-卡罗模拟表明，ToF校正程序减少了3%的情况下，在空间分布的核在焦平面的RITU的测量寿命的不确定性。然而，当使用更大的焦平面（即FAIR设施的Super-FRS）进行类似实验时，估计为12%。

Fast-timing measurements at the focal plane of a separator can suffer from poor timing resolution. This is due to the variations in time-of-flight (ToF) for photons travelling to a given detector, which arise from the changes in the implantation positions of the recoil nuclei emitting the γ rays of interest. In order to minimise these effects on timing measurements, a procedure is presented that improves fast-timing data by performing ToF corrections on an event-by-event basis. This method was used to correct data collected with an array of eight LaBr 3 detectors, which detected γ rays from spatially distributed 138 Gd recoil-implants at the focal plane of the Recoil-Ion-Transport-Unit (RITU) spectrometer. The Generalised Centroid Difference (GCD) method was used to extract a lifetime from data in conjunction with a new procedure to calibrate the time walk. The lifetime of the first 2+ state in 138 Gd, populated by the decay of the K π= 8− isomeric state, was measured to be 229 (24) ps using the ToF-corrected data, which is consistent within three standard deviations to the literature value. The results together with Monte-Carlo simulations show that the ToF correction procedure reduced the uncertainty in the measured lifetimes by 3% in the case of the spatially distributed nuclei at the focal plane of RITU. However,∼ 12% has been estimated for a similar experiment when using a larger focal plane ie the Super-FRS at the FAIR facility.

A time-of-flight correction procedure for fast-timing data of recoils with varying implantation positions at a spectrometer focal plane

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