Development of the photomultiplier tube readout system for the first Large-Sized Telescope of the Cherenkov Telescope Array

Masuda, S.; Konno, Y.; Barrio, J. A.; Bigas, O. Blanch; Delgado, C.; Freixas, Lluís; Gunji, Shuichi; Hadasch, D.; Hatanaka, K.; Ikeno, M.; Laguna, Jose Maria Illa; Inome, Yusuke; Ishio, Kazuma; Kubo, H.; Martínez, G.; Mazin, D.; Nakajima, D.; Nakamori, Takeshi; Ohoka, H.; Paoletti, R.; Ritt, Stefan Andreas; Rugliancich, A.; Saito, Takayuki; Sulanke, K.-H.; Takeda, J.; Tanaka, M.; Tanigawa, Shunsuke; Tejedor, Luis; Teshima, M.; Tsuchiya, Y.; Uchida, Tomohisa; Yamamoto, Tokonatsu

doi:10.22323/1.236.1003

Cited by 9 publications

(12 citation statements)

References 8 publications

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“…Since the PMT signal is fed to the readout board through the SCB, the routing of PMT signal has been carefully optimized to the same layout length. For details see [2].…”

Section: Slow Control Boardmentioning

confidence: 99%

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Development of Slow Control Boards for the Large Size Telescopes of the Cherenkov Telescope Array

Hadasch¹,

Konno²,

Kubo³

et al. 2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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The camera of the Large Size Telescopes (LSTs) of the Cherenkov Telescope Array (CTA) consists of 265 photosensor modules, each of them containing 7 photomultiplier tubes (PMTs), a slow control board (SCB), a readout board, and a trigger logic. We have developed the SCB, which is installed between the 7 PMTs and the readout board. The main task for SCBs is the controlling of the high voltages for the PMTs and the monitoring of their anode currents. In addition, the SCB provides the functionality to create test pulses that can be injected at the input of the PMT preamplifier in order to emulate a PMT signal without the need of setting a high voltage, or even without the PMT itself. The test pulses have a very similar width as the PMT pulses (less than 3 ns FWHM) and their amplitude can be adjusted in a wide dynamic range. These features allow us not only to test the functionality of the camera modules but also to fully characterize these. We report on the design and the functions of the SCB together with the results of test measurements.

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“…Since the PMT signal is fed to the readout board through the SCB, the routing of PMT signal has been carefully optimized to the same layout length. For details see [2].…”

Section: Slow Control Boardmentioning

confidence: 99%

“…Details on the Dragon board can be found in this contribution: 862 [2]. A photo of such a photosensor module with seven pixels is shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Development of Slow Control Boards for the Large Size Telescopes of the Cherenkov Telescope Array

Hadasch¹,

Konno²,

Kubo³

et al. 2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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“…PMT signals are sampled at 1 GHz by Domino Ring Sampler version 4 (DRS4) chips and digitized by an analog-to-digital converter (ADC). Fast sampling is essential to achieve the low energy threshold by reducing contamination of night sky background (NSB) light which enters each pixel with a rate of ⇠ 250 MHz [2]. The camera readout has two channels with di erent amplification, high gain (HG) and low gain (LG) channels, so that the wide dynamic range from 1 photoelectron (p.e.)…”

Section: Introductionmentioning

confidence: 99%

Camera Calibration of the CTA-LST prototype

Kobayashi¹,

Okumura²,

Cassol³

et al. 2021

Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021)

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The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray observatory that is expected to reach one order of magnitude better sensitivity than that of current telescope arrays. The Large-Sized Telescopes (LSTs) have an essential role in extending the energy range down to 20 GeV. The prototype LST (LST-1) proposed for CTA was built in La Palma, the northern site of CTA, in 2018. LST-1 is currently in its commissioning phase and moving towards scientific observations. The LST-1 camera consists of 1855 photomultiplier tubes (PMTs) which are sensitive to Cherenkov light. PMT signals are recorded as waveforms sampled at 1 GHz rate with Domino Ring Sampler version 4 (DRS4) chips. Fast sampling is essential to achieve a low energy threshold by minimizing the integration of background light from the night sky. Absolute charge calibration can be performed by the so-called F-factor method, which allows calibration constants to be monitored even during observations. A calibration pipeline of the camera readout has been developed as part of the LST analysis chain. The pipeline performs DRS4 pedestal and timing corrections, as well as the extraction and calibration of charge and time of pulses for subsequent higher-level analysis. The performance of each calibration step is examined, and especially charge and time resolution of the camera readout are evaluated and compared to CTA requirements. We report on the current status of the calibration pipeline, including the performance of each step through to signal reconstruction, and the consistency with Monte Carlo simulations.

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“…The LST camera is composed by 265 "PMT modules" (shown in figure 1a). Each module hosts a signal readout board, a slow control board and 7 pixel units, each one composed by a Cockcroft Walton HV supplier, a preamplifier and a high quantum efficiency Photo-Multiplier Tube (PMT) with a light collector in front of it [2]. In this contribution, we report the results of the quality inspection test of PMT module performed prior to the camera installation on the telescope, the current status of the commissioning operations, and the status of development of the SiPM-based module.…”

Section: Introductionmentioning

confidence: 99%

The calibration of the first Large-Sized Telescope of the Cherenkov Telescope Array

Sakurai¹,

Depaoli²,

López-Coto³

et al. 2019

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019)

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The Cherenkov Telescope Array (CTA) represents the next generation of very high-energy gamma-ray observatory, which will provide broad coverage of gamma rays from 20 GeV to 300 TeV with unprecedented sensitivity. CTA will employ three different sizes of telescopes, and the Large-Sized Telescopes (LSTs) of 23-m diameter dish will provide the sensitivity in the lowest energies down to 20 GeV. The first LST prototype has been inaugurated in October 2018 at La Palma (Canary Islands, Spain) and has entered the commissioning phase. The camera of the LST consists of 265 PMT modules. Each module is equipped with seven high-quantum-efficiency Photomultiplier Tubes (PMTs), a slow control board, and a readout board. Ensuring high uniformity and precise characterization of the camera is the key aspects leading to the best performance and low systematic uncertainty of the LST cameras. Therefore, prior to the installation on site, we performed a quality check of all PMT modules. Moreover, the absolute calibration of light throughput is essential to reconstruct the amount of light received by the telescope. The amount of light is affected by the atmosphere, by the telescope optical system and camera, and can be calibrated using the ring-shaped images produced by cosmic-ray muons. In this contribution, we will show the results of off-site quality control of PMT modules and on-site calibration using muon rings. We will also highlight the status of the development of Silicon Photomultiplier modules that could be considered as a replacement of PMT modules for further improvement of the camera.

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Development of the photomultiplier tube readout system for the first Large-Sized Telescope of the Cherenkov Telescope Array

Cited by 9 publications

References 8 publications

Development of Slow Control Boards for the Large Size Telescopes of the Cherenkov Telescope Array

Development of Slow Control Boards for the Large Size Telescopes of the Cherenkov Telescope Array

Camera Calibration of the CTA-LST prototype

The calibration of the first Large-Sized Telescope of the Cherenkov Telescope Array

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