The CANDLES trigger system for the study of Double Beta Decay of &lt;sup&gt;48&lt;/sup&gt;Ca

Maeda, Tsuyoshi; Ajimura, S.; Chan, W. M.; Fushimi, K.; Hazama, R.; Ichimura, Kunihiro; Iida, Tsutomu; Inukai, Y.; Ishikawa, T.; Kakubata, H.; Kishimoto, T.; Matsuoka, K.; Nakajima, K.; Nakatani, Noboru; Nomachi, M.; Ogawa, Izumi; Ohata, Toshihiro; Ohsumi, H.; Saka, M.; Sakamoto, K.; Seki, K.; Sugaya, Y.; Suzuki, K.; Tamagawa, Y.; Tanaka, Daisuke; Tetsuno, K.; Trang, V. T. T.; Umehara, S.; Wang, W.; Yoshida, S.; Yoshizawa, M.

doi:10.1109/rtc.2014.7097421

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…The data acquisition (DAQ) system consists of 74 channels of 500 MHz-8 bits-8 buffers flash analog-to-digital converters (FADCs), of which 62 are recording PMT waveforms and 12 are used for trigger purposes [12]. Trigger logics implemented in the global trigger control of our DAQ system include a dual-gate trigger to select the CaF 2 signal, and other trigger logics for monitoring purposes (a clock trigger of 3 Hz, a minimum bias trigger to select LS signals, a low-threshold dual-gate trigger to select CaF 2 signals at a lower threshold, and a cosmic-ray trigger) [13]. The clock trigger of 3 Hz is used to study single photoelectron charges in dark current and baseline fluctuation, which are discussed in Section II.…”

Section: B Candles Experimentsmentioning

confidence: 99%

A study on energy resolution of CANDLES detector

Khai,

Ajimura,

Chan

et al. 2020

Preprint

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In a neutrino-less double-beta-decay (0νββ) experiment, an irremovable two-neutrino double-beta-decay (2νββ) background surrounds the Q-value of the double beta decay isotope. The energy resolution must be improved to differentiate between 0νββ and 2νββ events. CAlcium fluoride for studies of Neutrino and Dark matters by Low Energy Spectrometer (CANDLES) discerns the 0νββ of 48 Ca using a CaF2 scintillator as the detector and source. Photomultiplier tubes (PMTs) collect scintillation photons. Ideally, the energy resolution should equal the statistical fluctuation of the number of photoelectrons. At the Q-value of 48 Ca, the current energy resolution (2.6%) exceeds this fluctuation (1.6%). Because of CaF2's long decay constant of 1000 ns, a signal integration in 4000 ns is used to calculate the energy. The baseline fluctuation (σ baseline ) is accumulated in the signal integration, degrading the energy resolution. Therefore, this paper studies σ baseline in the CANDLES detector, which has a severe effect (1%) at the Q-value of 48 Ca. To avoid σ baseline , photon counting can be used to obtain the number of photoelectrons in each PMT; however, a significant photoelectron signal overlapping probability in each PMT causes missing photoelectrons in counting and reduces the energy resolution. "Partial photon counting" reduces σ baseline and minimizes photoelectron loss. We thus obtain improved energy resolutions of 4.5-4.0% at 1460.8 keV (γ-ray of 40 K), and 3.3-2.9% at 2614.5 keV (γ-ray of 208 Tl). The energy resolution at the Q-value shows an estimated improvement of 2.2%, with improved detector sensitivity by factor 1.09 for the 0νββ half-life of 48 Ca.

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Section: B Candles Experimentsmentioning

confidence: 99%

A study on energy resolution of CANDLES detector

Khai,

Ajimura,

Chan

et al. 2020

Preprint

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“…The trigger board also controls the FADC buffer busy. The details of the trigger board and the communication mechanism between FADCs and the trigger board can be found in [11]. The SpaceWire router handles the routing function of the SpaceWire connection.…”

Section: Fadc and Trigger Handringmentioning

confidence: 99%

New DAQ System for the CANDLES Experiment

Suzuki

Ajimura

Chan

et al. 2015

IEEE Trans. Nucl. Sci.

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A new data acquisition (DAQ) system for the CAN-DLES experiment was developed using the SpaceWire protocol and the DAQ-Middleware framework. The CANDLES experiment uses a trigger board and Flash Analog-to-Digital Converters (FADCs). The SpaceWire helps us construct the DAQ system with a flexible and multi-path access to FADCs and the trigger board. FADCs have a ring buffer with three buffers to detect sequential decays from backgrounds. We developed the DAQ system with parallel read-out to reduce the dead time at high trigger rates using three read-out personal computers (PCs) that are connected to the three buffers in FADCs one by one. Each PC connects all FADCs and the trigger board and gathers a complete data set of one event without any event builder. The maximum DAQ speed of parallel read-out by three PCs was 2.4 times higher than that of single read-out. In order to collect event data sets from PCs, we built the network distributed DAQ system through Ethernet, which is naturally introduced with the DAQ-Middleware. To realize remote monitoring and histogram modification while the DAQ running, we also developed a dynamic online monitor system independent with the DAQ-Middleware.

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$\mu$ TCA DAQ System and Parallel Reading in CANDLES Experiment

Khai

Ajimura

Kanagawa

et al. 2019

IEEE Trans. Nucl. Sci.

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A new µTCA DAQ system was introduced in CANDLES experiment with SpaceWire-to-GigabitEthernet (SpaceWire-GigabitEthernet) network for data readout and Flash Analog-to-Digital Converters (FADCs). With SpaceWire-GigabitEthernet, we can construct a flexible DAQ network with multi-path access to FADCs by using off-the-shelf computers. FADCs are equipped 8 event buffers, which act as de-randomizer to detect sequential decays from the background. SpaceWire-GigabitEthernet has high latency (about 100 µsec) due to long turnaround time, while GigabitEthernet has high throughput. To reduce dead-time, we developed the DAQ system with 4 "crateparallel" (modules in crates are read in parallel) reading threads. As a result, the readout time is reduced by 4 times: 40 msec down to 10 msec. With improved performance, it is expected to achieve higher background suppression for CANDLES experiment. Moreover, for energy calibration, "event-parallel" reading process (events are read in parallel) is also introduced to reduce measurement time. With 2 "event-parallel" reading processes, the data rate is increased 2 times.

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The CANDLES trigger system for the study of Double Beta Decay of <sup>48</sup>Ca

Cited by 4 publications

References 7 publications

A study on energy resolution of CANDLES detector

A study on energy resolution of CANDLES detector

New DAQ System for the CANDLES Experiment

$\mu$ TCA DAQ System and Parallel Reading in CANDLES Experiment

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