Speaker
Description
In recent years, nuclear spectroscopy experiments have progressively replaced traditional analog setups with compact and affordable digital data acquisition systems. These systems reduce size and electronic complexity while maintaining adequate performance for a wide range of applications.
More recently, digital Time Differential Perturbed Angular Correlation (PAC) spectroscopy setups have been implemented at ISOLDE/CERN and at IFIMUP (Porto, Portugal) using CAEN DT5730s digitizers operating at a sampling rate of 500 MS/s with 14-bit ADC resolution. For PAC experiments employing probes such as $^{111m}$Cd and $^{111}$In, whose probe state has a half-life of 84 ns, the digital systems are fully operational and provide results equivalent to those obtained with conventional analog electronics.
However, PAC studies using probes with much shorter probing half-lives, such as $^{199m}$Hg (2.46 ns) and $^{181}$Hf (10.8 ns), remain limited. These experiments require an effective time stamp resolution significantly smaller than the digitizer sampling period of 2 ns, which cannot be achieved through hardware-based digital processing alone. This limitation can nevertheless be addressed through post-processing of the detector output signals, taking advantage of the high 14-bit ADC resolution.
In this work, the recorded waveforms were subjected to several off-line timing methods to refine the determination of event timestamps. Results obtained from 511-511 keV photon coincidences following the $\beta^+$ decay of $^{22}$Na show a clear improvement in time-stamping resolution. The method becomes effectively insensitive to sub-2 ns delays between the arrival times of the two photons. These results indicate that cost-effective digitizer units can be employed in modern detection experiments while preserving good timing performance and eliminating the need for precise channel synchronization.
| Which topic best fits your talk? | Condensed Matter Physics and Nanomaterials |
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| Affiliations | Faculdade de Ciências da Universidade do Porto |