A single ion discriminator ASIC prototype for particle therapy applications

Fausti, F.; Olave, J.; Giordanengo, S.; Ali, O. Hammad; Mazza, G.; Rotondo, F.; Wheadon, R.; Vignati, A.; Cirio, R.; Monaco, V.; Sacchi, R.

doi:10.1016/j.nima.2020.164666

Cited by 7 publications

(5 citation statements)

References 16 publications

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“…As an intermediate step toward this goal, dedicated LGAD strip detectors with an area of 2.7 × 2.7 cm 2 were produced by FBK, each one with 144 strips (Marti Villarreal (2023)). A dedicated 24channel Application Specific Integrated Circuit (ASIC) chip was also developed by Torino University and INFN, implementing the electronics for the amplification and fast discrimination of the signals from each readout channel, able to operate up to 100 MHz/channel (Fausti et al 2021). The sensors and the ASIC are the core of a prototype beam monitoring device under development, where the output signals from the ASICs are processed by an FPGA, with no additional dead time from the pile-up correction algorithms.…”

Section: Discussionmentioning

confidence: 99%

Performance of LGAD strip detectors for particle counting of therapeutic proton beams

Monaco,

Ali,

Bersani

et al. 2023

Phys. Med. Biol.

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Objective: The performance of silicon detectors with moderate internal gain, named Low-Gain Avalanche Diodes (LGADs), was studied to investigate their capability to discriminate and count single beam particles at high fluxes, in view of future applications for beam characterization and on-line beam monitoring in proton therapy.Approach: Dedicated LGAD detectors with an active thickness of 55 μm and segmented in 2 mm2 strips were characterized at two Italian proton-therapy facilities, CNAO in Pavia and the Proton Therapy Center of Trento, with proton beams provided by a synchrotron and a cyclotron, respectively. Signals from single beam particles were discriminated against a threshold and counted. The number of proton pulses for fixed energies and different particle fluxes was compared with the charge collected by a compact ionization chamber, to infer the input particle rates.Main results: The counting inefficiency due to the overlap of nearby signals was less than 1 % up to particle rates in one strip of 1 MHz, corresponding to a mean fluence rate on the strip of about 5⸱107 p/(cm2⸱s). Count-loss correction algorithms based on the logic combination of signals from two neighboring strips allow to extend the maximum counting rate by one order of magnitude. The same algorithms give additional information on the fine time structure of the beam. Significance. The direct counting of the number of beam protons with segmented silicon detectors allows to overcome some limitations of gas detectors typically employed for beam characterization and beam monitoring in particle therapy, providing faster response times, higher sensitivity, and independence of the counts from the particle energy. 

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Section: Discussionmentioning

confidence: 99%

Performance of LGAD strip detectors for particle counting of therapeutic proton beams

Monaco,

Ali,

Bersani

et al. 2023

Phys. Med. Biol.

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“…Two sensors with fully working strips from wafers 1 and 14 were tested with a clinical proton beam at CNAO, as shown in figure 1(d). The sensors were glued on a PCB designed for housing the digital front-end readout [1]. However, the board allows acquiring the two analog signals from the strip 1 (PiN) and the strip 146 (LGAD), located at the opposite edges of the sensor at a distance of 2.6 cm, thus allowing to perform studies of the signal shape.…”

Section: Methodsmentioning

confidence: 99%

“…Fulfilling the requirements and the ambitious goals of the interdisciplinary INFN project called MoVe-IT 2 (Modeling and Verification for Ion beam Treatment planning), the University and the National Institute for Nuclear Physics (INFN) of Torino are developing a prototype of a proton counter for the online monitoring of the fluence rate of therapeutic proton beams [1]. It is based on silicon Low Gain Avalanche Detector (LGAD) [2], which feature a gain implant added to provide a moderate gain, thus enhancing the signal in very small active thicknesses.…”

Section: Introductionmentioning

confidence: 99%

Characterization of large LGAD sensors for proton counting in particle therapy

et al. 2022

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A proton counter prototype based on Low Gain Avalanche Detector (LGAD) technology is being developed for the online monitoring of the fluence rate of therapeutic proton beams. The laboratory characterization of thin (45 μm and 60 μm) LGAD sensors segmented in 146 strips with an unprecedented large area of 2.6 × 2.6 cm2, covering the entire beam cross-section, is presented and discussed. The production includes 14 wafers with different characteristics, designed and produced at Fondazione Bruno Kessler (FBK) of Trento in 2020. The laboratory characterization was carried out at FBK, right after production, and at the University of Torino, after cutting the sensors, using a probe station with a power analyzer for the static DC electrical tests. The tests proved that the production was of very high quality. From 16 sensors randomly selected from different wafers, we observed consistency between the measurements performed at FBK and at the University of Torino, indicating that the cut did not degrade the performance. The sensors were also exposed to the clinical proton beam of the National Center for Oncological Hadrontherapy (CNAO, Pavia, Italy). The results show that LGADs allow achieving, in a very thin active thickness, a good separation between the proton signal, a peak of a very short duration, and the noise. This, combined with the large active area, will allow counting protons delivered with high efficiency at the high rates of a clinical beam.

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“…A dedicated fast Charge Sensitive Amplifier chip (ABACUS [5], figures 1(a) and (b)) with an area of 2 × 5 mm 2 and 24 channels has been designed to discriminate the expected signal pulses in a wide charge range (3-150 fC, corresponding to the energy released in silicon by clinical protons of 60-230 MeV) with a maximum dead-time of 10 ns to minimize pile-up counting inefficiencies at clinical fluence rates (10 6 -10 10 protons/cm 2 •s). The outputs of the chip are sent to an FPGA for the pulse counting, and the FPGA is connected to a computer where a dedicated LabVIEW program controls and integrates the FPGA inputoutputs, displays online the counting rate from each strip and stores the useful data.…”

Section: Countingmentioning

confidence: 99%

Monitoring therapeutic proton beams with LGAD silicon detectors

et al. 2022

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The University and the National Institute for Nuclear Physics of Torino are developing LGAD-based prototypes for beam monitoring in proton therapy. The direct measurement of single beam particles could overcome some features of currently used ionization chambers, such as slow charge collection and reduced sensitivity, which limit the implementation of advanced delivery techniques (e.g. rescanning). LGAD strip sensors have been designed and produced by Bruno Kessler Foundation (FBK, Trento) specifically for this project. A counter prototype to directly count individual protons at clinical fluence rates (106–1010 protons/cm2·s) and a telescope system to measure the beam energy with time-of-flight (TOF) techniques are described. Tests of LGAD silicon strip sensors performed on synchrotron and cyclotron beams of therapeutic centers, using a pin-hole ionization chamber for the independent measurement of the particle flux, already showed the possibility to keep the counting error <1% up to a beam fluence rate of few 108 protons/cm2·s. The ongoing tests of counting sensors readout by a dedicated fast charge sensitive amplifier chip are reported. The telescope system, made of two sensors at a distance up to 95 cm, allows measuring the beam energy in the clinical range (70–230 MeV) with a maximum deviation of 310 keV in respect to the nominal one, with an uncertainty of 500 keV, thus achieving the prescribed clinical accuracy of 1 mm in the range in water.

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A single ion discriminator ASIC prototype for particle therapy applications

Cited by 7 publications

References 16 publications

Performance of LGAD strip detectors for particle counting of therapeutic proton beams

Performance of LGAD strip detectors for particle counting of therapeutic proton beams

Characterization of large LGAD sensors for proton counting in particle therapy

Monitoring therapeutic proton beams with LGAD silicon detectors

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