Ⅱ-9. Instrumentation
RIKEN
Accel. Prog. Rep. 56 (2023)

RIKEN Accel. Prog. Rep. 56 (2023)

Development of a high-speed digital data acquisition system for theZD-MRTOF and β-decay experiments at F11V. H. Phong,∗1,∗2 S. Nishimura,∗1 M. Rosenbusch,∗3 A. Takamine,∗3 M. Wada,∗3 H. Ishiyama,∗1 P. Schury,∗3and J. M. Yap∗4 for the ZD-MRTOF Collaboration
A new project ZD-MRTOF has been launched tosurvey the masses of exotic nuclei using high-intensity
radioactive isotope beams at RIBF.1) Optimizing thedegrader thickness online is essential to maximize thestopping eﬃciency of rare isotopes in the He gas cell
during the experiment.2) Here, we report the performance of the newly introduced data acquisition systemdesigned for the ZD-MRTOF experiments using highspeed digitizers during the Spring campaign of the ZDMRTOF in 2022, where identiﬁcation of rare isotopes
under the beam rate of about 104 cps has been conﬁrmed with minimum event loss. The system is basedon the CAEN VME digitizers equipped with Field Programmable Gate Arrays (FPGAs), where signals thatexceed programmable thresholds are digitized and processed to extract amplitude and timing information.3)
The recorded signals are time-stamped and synchronized with the existing DAQ systems at RIBF thanks
to the use of LUPO modules,4) which distribute common 50 MHz clock signals to all digitizers.
Data acquisition is carried out using RCDAQ software.5) To combine online data from diﬀerent DDAQ
subsystems for Zerodegree, ZD-MRTOF and β-decay
setups, the ZeroMQ protocol6) was implemented. The
acquired data are distributed to data analysis computers on the network, where event reconstruction andtime correlations are performed online or oﬄine.
The performance of the DDAQ system under highrate conditions was tested using a cocktail beam ofneutron-rich Fe-Ge isotopes during the ZD-MRTOF
experiment NP2012-RIBF202. Signals from ZeroDegree spectrometer beamline detectors were readout using the CAEN V1730 digitizers running the DPP-PSD
and DPP-PHA ﬁrmwares. Figure 1 demonstrates theimprovement in deadtime using our DDAQ comparedto the existing CAMAC DAQ system, where deadtime
and event rate are evaluated based on a ﬁt of the distribution of time intervals between subsequent events toa non-extended deadtime model.7) A particle identiﬁcation (PID) plot obtained using our DDAQ system isalso shown. With the extracted event rate of 13.5 kHz,a dead time of ≈4 µs was obtained for our DDAQ system, compared to ≈377 µs for the CAMAC DAQ.
Our DDAQ system has also been successfully employed to readout the TOF signals of the ZD-MRTOFsystem, providing possibility to combine with the Ze∗1
∗2
∗3
∗4Fig. 1. Fitted distribution of the time interval between subsequent events (blue-ﬁlled) and a PID plot (inset) obtained with our DDAQ system compared to the distribution obtained with the BigRIPS CAMAC DAQ(gray-ﬁlled).

roDegree spectrometer PID information to monitor online the absolute eﬃciency of the ZD-MRTOF setup.
Figure 2 shows a TOF spectrum obtained with a 248 Cmﬁssion source,8) where the start signals of the mirror
ejection and the stop signals of the fast ion impact detector (ETP 14DM572)1) were recorded using a CAEN
V1730 digitizer running the DPP-PSD ﬁrmware.

Fig. 2. TOF spectrum obtained with our DDAQ system.

References
1) M. Rosenbusch et al., Nucl. Instrum. Methods Phys.
Res. A 1047, 167824 (2023).
2) S. Chen, RIKEN Accel. Prog. Rep. 54, 97 (2021).
3) https://www.caen.it/subfamilies/dpp/ .
4) H. Baba et al., Nucl. Instrum. Methods Phys. Res. A
777, 75 (2015).
5) M. L. Purschke, 2012 18th IEEE-NPSS Real Time Conference (IEEE, 2012).
6) ZeroMQ, https://zeromq.org/ .
7) J. W. Müller, Nucl. Instrum. Methods Phys. Res. A
301, 543 (1991).
8) J. M. Yap et al., in this report.

RIKEN Nishina Center
University of Science, Vietnam National University, Hanoi
Wako Nuclear Science Center (WNSC), IPNS, KEK
Department of Physics, University of Hong Kong- 99 -