Speaker
Description
The experimental campaign at the Rare-RI Ring (R3) facility aims to determine the masses of short-lived nuclei with a precision of 10$^{-6}$ using single-ion isochronous mass spectrometry. Although time-of-flight detectors are standard, Schottky detectors provide a non-destructive alternative for frequency detection. A high-sensitivity Schottky detector installed at R-MD3 was evaluated in a machine study (MS06) using a real-time spectrum analyzer^[1], resulting in clearly improved power spectral density. Meanwhile, the spectrum analyzer shared the BigRIPS-F3 trigger with the kicker magnet. Consequently, due to low transmission efficiency, the spectrum analyzer was activated uselessly even when no particles were injected into R3.
A new data acquisition scheme has been developed to overcome this issue. To confirm actual injection, a trigger counter consisting of a thin aluminum foil and a plastic scintillator was installed just before the kicker magnet. This counter detects secondary electrons emitted from the foil by passing ions. Together with kicker trigger signal, the counter signal is processed by an FPGA module to ensure valid triggering. Additionally, with an identical Schottky detector installed at R-MD1, this multiple Schottky system enables broadband measurements and efficient single-ion detection.
In this contribution, we will report on the current status of Schottky detectors and experimental plans for upcoming beam times.
Reference
[1] T. Yamaguchi, et al., RIKEN Accel. Prog. Rep. 58 (2025) 131