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

RIKEN Accel. Prog. Rep. 56 (2023)

Integration of VX2740B digitizer into babirl DAQ
S. Ogio,∗1 H. Baba,∗2 J. Zenihiro,∗1 R. Tsuji,∗1 and T. Yano∗1 for the ONOKORO Collaboration
We investigate cluster formation mechanism dependent on isotope and the kind of clusters by (p, pX)
cluster knock-out experiments and inverse kinematics
reconstruction with TOGAXSI array,1) which named
ONOKORO project.2) It is diﬃcult that approximately
100 ch signals from TOGAXSI array are processed ina conventional analog circuit and combined into output triggers based (p, pX) kinematics. CAEN digitizer
VX2740B is a promising candidate to obtain data fromGAGG scintillators of TOGAXSI array, process complex
logic signals, and generate triggers.
VX2740B digitizer is an 125 MS/s ADC having 64
analog inputs, compliant with VME64X standard which
has a 62.5 MHz internal clock. Pulse height is sampled
by the 16-bit ADC in full-scale range of 2 Vpp. TheVME crate is used only as a power supplier. Data isobtained via USB-3.0, 1/10 Gigabit Ethernet, or optical link cables attached to the front panel. Digitizedsignal, which is temporarily stored in 2.5 GB memory,is processed in FPGA Xilinx Zynq UltraScale+ implemented on VX2740B board. If the data rate is too high,the memory becomes full, VX2740B outputs intrinsic
busy signals and the eﬃciency is signiﬁcantly suppressed.
CAEN provides ﬁrmware and C libraries named “FELib”
for the basic waveform processing. Here we have developed a new program to integrate VX2740B into babirlDAQ.3) It is called as babies for VX2740B and it utilizes
FELib.
The H424 experiment4) was carried out in PH2 course
at QST, HIMAC and we conﬁrmed that VX2740B canwork properly under the experiment condition as a ﬁrst
development. Beam nuclide is 4 He, 16 O, 40 Ar and allof their energy were set to 230 MeV/nucleon. ESPRI
chamber, drift chambers and ONOKORO chamber werealigned from the beam upstream to the downstream.
The detector data except those of VX2740B were obtained by MPV5) which is a VME-based DAQ system.
24 signals from GAGG in the ONOKORO chamber and2 signals from GAGG read out with photodiodes in theESPRI chamber were divided and entered into VX2740Band conventional CAEN ADC V785 installed in MPV.
In this experiment, “scope” ﬁrmware was used to acquire waveforms by VX2740B. VX2740B was driven by
a common external trigger from the babirl DAQ whiledata from VX2740B and the babirl DAQ were saved inseparate ridf ﬁles. To synchronize the timestamp information, which eanbles merging separately stored data, a62.5 MHz internal clock of VX2740B was distributed toMPV.
As a result, we have found that VX2740B did not output busy and then VX2740B event counts are almost
the same as babirl DAQ when input channels were 26∗1∗2

Department of Physics, Kyoto University
RIKEN Nishina Centerand trigger rate was approximately 1 kHz. As shown inFig. 1, waveforms are correctly obtained. We analyzed
the ridf ﬁles uniﬁed with timestamps in order to compare
the ADC values of V785 obtained by existing DAQ withthe PHA values calculated from waveforms acquired byVX2740B, resulting the linear correlation event by event(Fig. 2).

Fig. 1. Waveforms obtained by VX2470B.

Fig. 2. Pulse height correlation.

In summary, we have developed the babies for
VX2740B and succeeded in integrating it into babirl
DAQ. In the HIMAC experiment, we operated it simultaneously with conventional ADC V785 and conﬁrmedthat the data was obtained correctly. In future studies,
we plan to test the triggering function of VX2740B with
“DPP-PHA” ﬁrmware provided by CAEN.
References1) T. Uesaka et al., RIBF Construction Proposal, NP2112SAMURAI72 (2021).
2) T. Uesaka et al., Grant-in-Aid for Specially Promoted Research (2021).
3) H. Baba et al., Nucl. Instrum. Methods Phys. Res. A 616,65 (2010).
4) R. Tsuji et al., in this report.
5) H. Baba et al., IEEE Trans. Nucl. Sci. 68, 1841 (2021).

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