Giga-sample Pulse Acquisition and Digital Processing for Photomultiplier Detectors

Walewski, Wojciech; Nowakowski, Patryk Nowak vel; Makowski, Dariusz

doi:10.1007/s10894-022-00320-0

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…A typical CR − (RC) n analog pulse-shaper amplifier consists of one differentiator followed by n integrators to produce a semi-Gaussian output pulse. This type of analog shaper can be replaced by modern digital shaping systems, which offer several advantages [31,32]. In these systems, the CSA output is directly digitized using a fast ADC and is immediately processed by a customized DPP.…”

Section: Digital Pulse Shapingmentioning

confidence: 99%

Data Analysis and Filter Optimization for Pulse-Amplitude Measurement: A Case Study on High-Resolution X-ray Spectroscopy

Mannatunga

Valinoti

Samayoa

et al. 2022

Sensors

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In this study, we present a procedure to optimize a set of finite impulse response filter (FIR) coefficients for digital pulse-amplitude measurement. Such an optimized filter is designed using an adapted digital penalized least mean square (DPLMS) method. The effectiveness of the procedure is demonstrated using a dataset from a case study on high-resolution X-ray spectroscopy based on single-photon detection and energy measurements. The energy resolutions of the Kα and Kβ lines of the Manganese energy spectrum have been improved by approximately 20%, compared to the reference values obtained by fitting individual photon pulses with the corresponding mathematical model.

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Section: Digital Pulse Shapingmentioning

confidence: 99%

Data Analysis and Filter Optimization for Pulse-Amplitude Measurement: A Case Study on High-Resolution X-ray Spectroscopy

Mannatunga

Valinoti

Samayoa

et al. 2022

Sensors

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“…The rapid development of fast FPGAs (Field Programmable Gate Array) and ADC (Analogue-to-Digital Converter) enabled the use of digital pulse processing methods [10]. Algorithms, tuned for a specific shape of PMT signal can be implemented in the FPGA and used to discriminate PMT pulses in real-time [11].…”

Section: Challenges With Signal Transmission In Hard X-ray Diagnostic...mentioning

confidence: 99%

PMT Signal Transmission for Hard X-Ray Diagnostics of Future Tokamaks

Nowakowski

Makowski²,

Walewski³

2022

J Fusion Energ

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A pair of a scintillator and a Photomultiplier Tube (PMT) is often used as a Hard X-Ray (HXR) radiation detector in existing tokamaks such as JET, EAST, COMPASS or ASDEX-U. Future nuclear fusion reactors such as ITER or DEMO will use more powerful magnets and confine a larger volume of hot plasma. Placement of the detectors used for plasma diagnostic will be constrained by high temperatures, magnetic fields and ionizing radiation present near the tokamak vessel. It might be necessary to move detectors away from tokamak to a safer location. This might generate problems with pulse discrimination and transmission of the signal. In the case of the ITER tokamak, sensitive electronics such as digitizers cannot be installed close to the reactor due to harsh environmental conditions. A new approach to component placement is needed to protect those devices. The PMT signal will be transmitted via an over 100 m long coaxial cable to the digitizer located in the adjacent diagnostic building. The long cables will introduce additional signal attenuation. Also, the RF noise from the tokamak environment can couple into the signal. To improve the signal-to-noise ratio a dedicated PMT amplifier with a high output range (from + 1.5 to − 11 V) was proposed.The paper presents issues with signal transmission in HXR diagnostic systems and includes a discussion on the methodology of PMT signal transmission in the conditions of the future tokamaks. A proposal of guidelines for selection of the signal chain components and design of a dedicated PMT amplifier is part of this paper.

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Evaluation of optical transmission across the ITER hard x-ray monitor system designed for the first plasma scenarios

Nowakowski

Makowski

Jabłoński

et al. 2022

Review of Scientific Instruments

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Hard x-ray (HXR) spectroscopy is applied for diagnostics of runaway electrons in nuclear fusion reactors. The scintillation counter is one of the most commonly used types of detectors for HXR spectroscopy. It consists of a detector that emits light when excited by HXR radiation (scintillator) directly coupled to a PMT (Photomultiplier Tube) that converts light pulses into an electrical signal. This type of detector is commonly used in existing tokamaks, such as Joint European Torus (JET), Experimental Advanced Superconducting Tokamak (EAST), Compact Assembly (COMPASS), and Axially Symmetric Divertor Experiment (ASDEX-U). In all these cases, the scintillator is directly coupled to the PMT to provide the best possible light transmission efficiency. The Hard X-ray Monitor (HXRM) is one among the first plasma diagnostic systems at ITER that provides information about the energy distribution of runaway electrons inside a tokamak by HXR spectroscopy. This system also uses a scintillator and a PMT as a detector. Due to the heavy shielding of the blanket modules, vacuum vessel, and port-plugs, it is not possible to assemble the scintillator outside the tokamak vacuum vessel. The PMT detector cannot be installed in the close vicinity of the tokamak due to either the significant magnetic field or temperature. A possible solution is to decouple the scintillator from the PMT and place the PMT inside the port-cell. Light pulses will be transmitted to the PMT via a 12 m long optical fiber bundle. Evaluation of the optical transmission was carried out to assess the performance of the HXR monitor and verify possible problems related to the PMT pulse discrimination under low light conditions.

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Giga-sample Pulse Acquisition and Digital Processing for Photomultiplier Detectors

Cited by 3 publications

References 15 publications

Data Analysis and Filter Optimization for Pulse-Amplitude Measurement: A Case Study on High-Resolution X-ray Spectroscopy

Data Analysis and Filter Optimization for Pulse-Amplitude Measurement: A Case Study on High-Resolution X-ray Spectroscopy

PMT Signal Transmission for Hard X-Ray Diagnostics of Future Tokamaks

Evaluation of optical transmission across the ITER hard x-ray monitor system designed for the first plasma scenarios

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