J. J. Velthuis
A5045601408- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- CCD and CMOS Imaging Sensors
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Diamond and Carbon-based Materials Research
- Superconducting Materials and Applications
- Radiation Therapy and Dosimetry
- Advanced Radiotherapy Techniques
- Nuclear physics research studies
- Stochastic processes and statistical mechanics
- Radiation Effects in Electronics
- Distributed and Parallel Computing Systems
- Geophysical Methods and Applications
- Cosmology and Gravitation Theories
- Particle accelerators and beam dynamics
- Astrophysics and Cosmic Phenomena
University of Bristol
2016-2025
University of South China
2019-2023
Swansea University
2017-2023
University of Cambridge
2023
Istituto Nazionale di Fisica Nucleare, Sezione di Milano
2023
University of Milan
2023
Lancaster University
2023
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2023
University of Liverpool
2004-2021
Anhanguera (Brazil)
2021
The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in LHCb experiment. performance of during first years its physics operation reviewed. system operated vacuum, uses bi-phase CO2 cooling system, and sensors are moved to 7 mm from LHC beam for data taking. stability these characteristic features described, details material budget given. calibration timing processing algorithms implemented FPGAs described. fully characterised. have...
The Mu3e experiment aims to find or exclude the lepton flavour violating decay $\mu \rightarrow eee$ at branching fractions above $10^{-16}$. A first phase of using an existing beamline Paul Scherrer Institute (PSI) is designed reach a single event sensitivity $2\cdot 10^{-15}$. We present overview all aspects technical design and expected performance phase~I detector. high rate up $10^{8}$ muon decays per second low momenta electrons positrons pose unique set challenges, which we tackle...
A large area scanner for cosmic muon tomography is currently being developed at University of Bristol.
This work describes the performance of a muon tracker built with high resolution glass resistive plate chambers. The is result collaboration between University Bristol and Atomic Weapon Establishment to develop reliable cost effective system scan shipping containers in search special nuclear materials. current setup consists 12 detection layers, each comprised chamber read out by 1.5 mm pitch strips. For most layers we achieved an efficiency better than 95%, purity above 95% signal-to-noise...
We present a novel approach to the detection of special nuclear material using cosmic rays. Muon Scattering Tomography (MST) is method for muons scan cargo containers and vehicles material. Cosmic are abundant, highly penetrating, not harmful organic tissue, cannot be screened against, can easily detected, which makes them suited use scanning. Muons undergo multiple Coulomb scattering when passing through material, amount roughly proportional square atomic number Z By reconstructing incoming...
The non-invasive imaging of dense objects is particular interest in the context nuclear waste management, where it important to know contents containers without opening them. Using Muon Scattering Tomography (MST), possible obtain a detailed 3D image container on reasonable timescales, showing both high and low density materials inside. We show performance such method Monte Carlo simulation dummy drum object containing different shapes materials. has been tuned with our MST prototype...
Diffusing alpha-emitters radiation Therapy (DaRT) is an interstitial brachytherapy technique using 224Ra seeds. For accurate treatment planning a good understanding of the early DNA damage due to α-particles required. Geant4-DNA was used calculate initial and radiobiological effectiveness with linear energy transfer (LET) values in range 57.5–225.9 keV/μm from decay chain. The impact base pair density on has been modelled, as this parameter varies between human cell lines. Results show that...
Purpose:Diffusing alpha-emitters radiation therapy (DaRT) is a brachytherapy technique using α-particles to treat solid tumours. The high linear energy transfer (LET) and short range of make them good candidates for the targeted treatment cancer. Treatment planning DaRT requires understanding dose from other particles released in 224Ra decay chain.Methods:The Geant4 Monte Carlo toolkit has been used simulate seed better understand contribution all DNA damage due this treatment.Results:Close...
The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the interaction region. During first two years of data collection, 84 VELO sensors have been exposed range fluences up maximum value approximately 45 × 1012 1 MeV neutron equivalent (1 neq). At operational sensor temperature −7 °C, average rate current increase 18 μA per fb−1, in excellent agreement with predictions. effective bandgap has determined using...
Solid state detectors with nanosecond response times to incoming radiation are increasingly present at the forefront of radiotherapy dosimetry research. The fast time materials, such as diamond, allow pulse by dosimetry. There is a trend in move toward shorter treatments, using fewer but more intense pulses varying rates and intensities. This makes possibility measuring individual very attractive would intervention during treatment not just afterwards. Here, an analogue front end has been...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> For the detection of secondary vertices long lived particles containing bottom and charm quarks at International Linear Collider (ILC), a DEPFET pixel detector is one technologically favored options. In sensor MOSFET integrated on sidewards depleted silicon bulk sensor, thus combining advantages fully with in-pixel amplification. matrices have been characterized in high energy particle beam....
An analysis method of identifying materials using muon scattering tomography is presented, which uses previous knowledge the position high-Z objects inside a container and distinguishes them from similar materials. In particular, simulations were performed in order to distinguish block Uranium blocks Lead Tungsten same size, concrete-filled drum. The results show that, knowing shape analysis, it possible 5 × cm3 these with about 4h exposure, down 2 70h data multivariate (MVA). MVA several...