Federico Fausti

Quality assurance of carbon ion and proton beams: A feasibility study for using the 2D MatriXX detector

PURPOSE The quality assurance (QA) procedures in particle therapy centers with active beam scanning make extensive use of films, which do not provide immediate results. The purpose of this work is to verify whether the 2D MatriXX detector by IBA Dosimetry has enough sensitivity to replace films in some of the measurements. METHODS MatriXX is a commercial detector composed of 32×32 parallel plate ionization chambers designed for pre-treatment dose verification in conventional radiation therapy. The detector and GAFCHROMIC® films were exposed simultaneously to a 131.44MeV proton and a 221.45MeV/u carbon-ion therapeutic beam at the CNAO therapy center of Pavia - Italy, and the results were analyzed and compared. RESULTS The sensitivity MatriXX on the beam position, beam width and field flatness was investigated. For the first two quantities, a method for correcting systematic uncertainties, dependent on the beam size, was developed allowing to achieve a position resolution equal to 230μm for carbon ions and less than 100μm for protons. The beam size and the field flatness measured using MatriXX were compared with the same quantities measured with the irradiated film, showing a good agreement. CONCLUSIONS The results indicate that a 2D detector such as MatriXX can be used to measure several parameters of a scanned ion beam quickly and precisely and suggest that the QA would benefit from a new protocol where the MatriXX detector is added to the existing systems.

Innovative thin silicon detectors for monitoring of therapeutic proton beams: Preliminary beam tests

To fully exploit the physics potentials of particle therapy in delivering dose with high accuracy and selectivity, charged particle therapy needs further improvement. To this scope, a multidisciplinary project (MoVeIT) of the Italian National Institute for Nuclear Physics (INFN) aims at translating research in charged particle therapy into clinical outcome. New models in the treatment planning system are being developed and validated, using dedicated devices for beam characterization and monitoring in radiobiological and clinical irradiations. Innovative silicon detectors with internal gain layer (LGAD) represent a promising option, overcoming the limits of currently used ionization chambers. Two devices are being developed: one to directly count individual protons at high rates, exploiting the large signal-to-noise ratio and fast collection time in small thicknesses (1 ns in 50 μm) of LGADs, the second to measure the beam energy with time-of-flight techniques, using LGADs optimized for excellent time resolutions (Ultra Fast Silicon Detectors, UFSDs). The preliminary results of first beam tests with therapeutic beam will be presented and discussed.

The integration and testing of the Mini-EUSO multi-level trigger system

Abstract The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station (ISS) in low Earth orbit. The main goal of the mission is to map the Earth in the UV, thus increasing the technological readiness level of future EUSO experiments and to lay the groundwork for the detection of Extreme Energy Cosmic Rays (EECRs) from space (Ebisuzaki et al., 2014). Due to its high time resolution of 2.5 μs, Mini-EUSO is capable of detecting a wide range of UV phenomena in the Earth’s atmosphere. In order to maximise the scientific return of the mission, it is necessary to implement a multi-level trigger logic for data selection over different timescales. This logic is key to the success of the mission and thus must be thoroughly tested and carefully integrated into the data processing system prior to the launch. This article introduces the motivation behind the trigger design and details the integration and testing of the logic.

Design of a 64 channels current-to-frequency converter ASIC, front-end electronics for high intensity particle beam detectors

A new wide-input dynamic range, 64-channels current-to-frequency converter ASIC has been designed and is now under characterization. This chip, nicknamed TERA09, has been realized to equip the front-end readout electronics for the new generation of beam monitor chambers for particle therapy applications. In this field, the trend in the accelerator development is moving toward compact solutions providing high-intensity pulsed-beams. However, such a high intensity will saturate the present readout of the beam monitor chambers. In order to deal with the technology innovations in the particle therapy, the chip described in this work is able to cope with a higher maximum intensity while keeping high resolution by working on a six orders of magnitude conversion-linearity zone (hundreds of pA to hundreds of μA), with a gain spread in the order of 1-3% (r.m.s.), with a 200fC charge resolution.

Laboratory and beam test results of TOFFEE ASIC and ultra fast silicon detectors

In this report we present measurements performed on the full custom ASIC TOFFEE, designed to pre-amplify and discriminate signals of Ultra Fast Silicon Detectors. The ASIC has been characterized in laboratory with custom test boards, and with infrared laser light hitting the sensor emulating a minimum ionizing particle signal. Laser measurements show that a jitter term better than 50 (40) ps is achievable with a 10 (12) fC input charge. We also present some preliminary results on the TOFFEE performances, as obtained during recent beam tests with a 180 GeV/c pion beam, on the SPS-H8 beam line at CERN.

A Multi-Level Triggering System for the Mini-EUSO UV Telescope

As a pathfinder for the JEM-EUSO mission, Mini-EUSO is a 25cm diameter telescope which is going to be launched and positioned inside the International Space Station (ISS) in 2018. The main scientific goal of this mission is the achievement of a state-of-the-art UV map of the Earth from a 400 Km altitude, with

The Mini-EUSO multi-level trigger algorithm and its performance

\sim 6

Mini-EUSO photodetector module data processing system

km of pixel spatial resolution, collecting data though a multi-level triggering system. The signal is collected with Multi-Anode Photo Multiplier Tubes (MAPMTs) and digitized by means of custom chips. The raw data moves then to a central system, the Zynq Board, where the trigger operates a data selection dividing different classes of events characterized by specific time scales. The acquired UV map will be used as discrimination threshold for the Extreme Energy Cosmic-Ray detection.

Control of the Dose Distribution in Charged Particle Therapy

The Mini-EUSO telescope is designed by the JEM-EUSO Collaboration to observe the UV emission of the Earth from the vantage point of the International Space Station in low Earth orbit. The main goal ...

Development of a front-end electronics for an innovative monitor chamber for high-intensity charged particle beams

Mini-EUSO is a UV telescope which is developed by the JEM-EUSO collaboration to be placed on board the International Space Station (ISS) to carry out measurements of UV atmosphere airglow and transient luminous events (TLEs) in a wide field of view (