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Tesi di laurea

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Tesi di laurea

16 gen/23

FLUKA Energy Deposition Studies for an Innovative Superconducting Gantry for Carbon Ions

ABSTRACT

The National Center for Oncological Hadrontherapy (CNAO, Pavia) is presently designing a carbon ion gantry, i.e. a device responsible for rotating the beam around the patient for treatment at different angles.
While gantries for electron, photon and proton beams can be found nowadays on the market as turn-key machines, only four gantries for carbon ion beams have been built in the world.
In fact, the high magnetic rigidity of the carbon ion beams implies the deployment of magnets at the forefront of technology and very complex rotating structures.

The gantry design being considered by CNAO is based on superconducting (SC) magnets.
While SC magnets allow to obtain high magnetic fields, they are sensitive to local releases of energy in the cables carrying current, potentially inducing a quench (i.e. a sudden change of the magnet state to the normal conducting one); if the quench is not properly handled, it can permanently damage the magnet.
Local releases of energy can originate from rapid current transients or from beam losses.
An energy margin to the quench is always considered in the design of SC magnets, to minimise the probability of a quench.

The thesis activity is aimed at estimating the energy release in the SC cables of the magnets being designed for the CNAO gantry and assessing the respective margin to quench; the focus is on events of energy deposition induced by beam losses.
The estimation is obtained by means of simulations with FLUKA, one of the Monte Carlo codes most widely used worldwide for simulating particle-matter interactions.

FURTHER INFO

  • Expected duration of activity (including thesis write-up): 12 months
  • Preferred technical skills: fundamentals of particle-matter interaction, basic knowledge of coding (python, C/C++, Fortran)
  • Most suited curriculum studiorum of the candidate: physics, nuclear engineering
  • Required soft skills: attitude to problem solving, will to take initiative, eagerness to learn, openness to discussions
  • References: alessio.mereghetti@cnao.it, enrico.felcini@cnao.it, marco.pullia@cnao.it

 

Study of Slow Beam Extraction

ABSTRACT

The National Center for Oncological Hadrontherapy (CNAO, Pavia) is one of the four cancer treatment facilities in Europe delivering proton and carbon ion beams for cancer treatment.
The CNAO synchrotron is the key machine for producing the treatment beams.
The mechanism of extraction of the beam from the synchrotron is based on a third-order resonance, where beam particles are made unstable by an active element.
At CNAO, the two beam excitation mechanisms for slow extraction used worlwide in similar installations, i.e. the betatron-core and the Radio Frequency Knock-Out (RFKO), are presently available; while the former is deployed for cancer treatment, the latter is still in a commissioning phase.

The thesis activity consists of simulating the beam extraction driven by either mechanisms with the aim of optimising key parameters, like frequency and strength of the driving kicker for the RFKO.
The simulations will be performed with top-quality codes like MADX, PTC and XSuite, all developed by teams in world-class accelerator facilities.
If possible with the existing hardware and without hindering the treatment schedule, dedicated tests of the simulated procedures with beam could be foreseen.

FURTHER INFO

  • Expected duration of activity (including thesis write-up): 12 months
  • Preferred technical skills: fundamentals of accelerator physics, fundamentals of mechanical statistics, basic knowledge of coding (python, C/C++, Fortran) and Linux system
  • Most suited curriculum studiorum of the candidate: physics, nuclear engineering
  • Required soft skills: attitude to problem solving, will to take initiative, eagerness to learn, openness to discussions.
  • References: alessio.mereghetti@cnao.it, marco.pullia@cnao.it

 

Characterisation of a new aquisition system for the Schottky Monitor at the CNAO Synchrotron

ABSTRACT

The hadron synchrotron of the National Center for Oncological Hadrontherapy (CNAO, Pavia) is the key machine for producing the beams necessary for all the cancer treatments delivered by the center.
The synchrotron is equipped with a Schottky monitor capable to measure collective quantities of the circulating beam (e.g. revolution frequency, tune, chromaticity, etc...) in a non-destructive way; therefore, its use is of great operational interest, especially in the perspective of monitoring treatment beams.
The acquisition system, although successfully tested with particle beams at CERN, has not so far allowed a routine use of the monitor, not even as part of the regular machine checks.

The thesis activity aims to develop a new acquisition set-up for the Schottky monitor, based on a digital oscillocscope with high sampling frequency and an off-line frequency analysis of the acquired signals.
The activity is based on two pillars: the first one is the characterisation of the new acquisition system and of the key aspects of the Schottky analysis by means of measurements carried out at a test bench with simulated signals; the actual measurements with beams circulating in the synchrotron will be the second one.

FURTHER INFO

  • Expected duration of activity (including thesis write-up): 12 months
  • Preferred technical skills: basic knowledge of FFT algrithms, methods of signal treatment, electronics, MatLab
  • Most suited curriculum studiorum of the candidate: physics, nuclear engineering, electronics engineering
  • Required soft skills: attitude to problem solving, will to take initiative, eagerness to learn, openness to discussions
  • References: alessio.mereghetti@cnao.it, claudio.viviani@cnao.it, anna.parravicini@cnao.it, marco.pullia@cnao.it
  • Azienda con sistema di gestione per la Qualità Certificata
  • Centro registrato in QuESTIO, la mappatura dei soggetti attivi nel campo della ricerca e dell'innovazione
  • Lombardia Life Sciences
  • ESTRO Institutional Member 2019