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Proton Therapy (PT) was first proposed in the 1940s. Application of this knowledge was largely led over the next fifty years by accelerator laboratories, but now also by commercial companies. Availability of PT is increasing but is limited by three factors: facility size, prompt/induced radiation, and treatment cost. Compact cyclotrons/synchro cyclotrons for single-room facilities have reduced space requirements. linacs can avoid high radiation levels. Yet treatment costs have remained stubbornly high, driven largely by maintenance and staffing costs over the typical 20-30 year facility lifetime. Current technology cannot simultaneously reduce these three factors. By using a long linac, the Alceli approach sacrifices size limitations, to gain massive improvements in treatment cost and radiation levels. Quadrupling the length of a linac results in a sixteen-fold reduction in RF power per cavity. Along with other innovations in our design, this leads to a modular warm linac with distributed solid-state RF amplification, easy and cheap to manufacture and maintain, requiring no water cooling, and a treatment cost of 1/10th of current facilities, making PT much more affordable., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

Tanning of leather for clothing, shoes and handbags uses potentially harmful chemicals that are often run off into local water supplies or require a large carbon footprint to safely recover these pollutants. In regions of the world with significant leather production this can lead to a significant environmental impact. However recent studies have suggested that leather can instead be tanned using a combination of electron beams in a process inspired by the industrial crosslinking of polymers, to drastically reduce the quantity of wastewater produced in the process; thereby resulting in a reduced environmental impact as well as potential cost savings on wastewater treatment. In this talk, initial studies of leather tanning will be presented as well as accelerator designs for use in leather irradiation., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

Tanning of leather for clothing, shoes, and handbags uses potentially harmful chemicals that often run off into local water supplies or require a large carbon footprint to safely recover these pollutants. In regions of the world with significant leather production, this can lead to a significant environmental impact. However recent studies have suggested that leather can instead be tanned using a combination of electron beams in a process inspired by the industrial crosslinking of polymers, to drastically reduce the quantity of wastewater produced in the process; thereby resulting in a reduced environmental impact as well as potential cost savings on wastewater treatment. In this talk, initial studies of leather tanning will be presented as well as accelerator designs for use in leather irradiation.

A low energy Fixed Field Alternating Gradient (FFAG) accelerator has been designed for the production of radioisotopes. Tracking studies have been conducted using the OPAL code, including the effects of space charge. Radioisotopes have a wide range of uses in medicine, and recent disruption to the supply chain has seen a renewed effort to find alternative isotopes and production methods. The design features separate sector magnets with non-scaling, non-linear field gradients but without the counter bends commonly found in FFAG's. The machine is isochronous at the level of 0.3% up to at least 28 MeV and hence able to operate in Continuous Wave (CW) mode. Both protons and helium ions can be used with this design and it has been demonstrated that proton beams with currents of up to 20 mA can be accelerated. An interesting option for the production of radioisotopes is the use of a thin internal target. We have shown that this design has large acceptance, ideal for allowing the beam to be recirculated through the target many times, the lost energy being restored on each cycle. In this way, the production of Technetium-99m, for example, can take place at the optimum energy., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

In this paper we present the design for a low-cost RF cavity capable of accelerating protons from 100 keV to 1 MeV. The system is designed to meet the specifications from the proposed Alceli LTD medical proton therapy linac, to deliver a 1 nA proton beam current with a 1 kHz repetition rate. We present a design of an RF normal conducting (NC) re-entrant Cu cavity operating at 40 MHz consisting of a coupled two cavity system, both driven by a single Marx generator. The choice of such a low operating frequency for the cavity system enables us to use a relatively low-cost cost Marx Generator as the RF source. Marx generators work in a similar fashion to a Cockcroft-Walton accelerator (without the expensive components), creating a high-voltage pulse by charging a number of capacitors relatively slowly in parallel, then rapidly discharging in series, via spark gaps. Marx generators can deliver 2.5 GW, 1 ns pulses, with rise times of 200 ps, and (relatively) low jitter., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The radioisotope Technetium-99m (99m Tc) is used in 85% of all nuclear medicine procedures. 99mTc is produced from its precursor Molybdenum-99 (99 Mo), whose production is nearly all from one of only five ageing research reactors. Recently a number of accelerator-based methods have been proposed to fill this gap and to diversify this supply chain. In this paper we present a compact (4 m) 10 mA, 3.5 MeV accelerator design, to generate 99Mo via low-energy neutron bombardment of 98Mo. We consider a Li(p,n) target for neutron production, and propose the use of a novel moderator to optimally shift the target output neutron spectrum into the epithermal region of the 98Mo. This paper specifically focuses on numerical studies for an optimised target design capable of handling the thermal load.

Reliability has been identified as a key factor limiting the development of certain particle accelerator applications, for example Accelerator-Driven Systems (ADS) for energy production and waste-transmutation. Previous studies of particle accelerator reliability have been undertaken using conventional techniques, such as Reliability Block Diagrams (RBD), Fault Tree Analysis (FTA), etc. Although limited data surrounding components and their failure modes limits the applicability of conventional techniques for analysing the reliability of particle accelerators. In addition industrial applications of particle accelerators, i.e. energy production, require a real time response to failure. In this paper we exam- ine a holistic approach to accelerator reliability modelling using Electric Network Frequency (ENF) criterion to look for emergent behaviour of the particle accelerator, from com- plex datasets, such as beam current/charge, created by the diagnostics systems during the machines operation. To look for predictive characteristics just prior to a machine trip.

The radioisotope Technetium-99m (^{99m}Tc) is used in 85\% of all nuclear medicine procedures. ^{99m}Tc is produced from its precursor Molybdenum-99 (⁹⁹Mo), which until recently was produced in only five research reactors worldwide. Recently a number of accelerator-based methods have been proposed to fill this gap and to diversify this supply chain. In the paper we present our base compact (4 m) 10 mA 3.5 MeV accelerator design, to generate low-energy neutrons via fusion. In this design we increase neutron capture with a novel moderator assembly to shift the neutron spectrum into the epithermal resonance region of the ⁹⁸Mo capture cross-section to create ⁹⁹Mo. In this paper we examine Li(p, n) reactions for neutron production. Specifically focused on a numerical studies for an optimised target design capable of handling the heat load., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Reliability has been identified as a key factor limiting the development of certain particle accelerator applications, for example Accelerator-Driven Systems (ADS) for energy production and waste-transmutation*. Previous studies of particle accelerator reliability have been undertaken using conventional techniques, such as Reliability Block Diagrams (RBD), Fault Tree Analysis (FTA), etc. Although limited data surrounding components and their failure modes limits the applicability of conventional techniques for analysing the reliability of particle accelerators. In addition industrial applications of particle accelerators, i.e. energy production, require a real time response to failure. In this paper we examine a holistic approach to accelerator reliability modelling using Electric Network Frequency (ENF) criterion to look for emergent behaviour of the particle accelerator, from complex datasets, such as beam current/charge, created by the diagnostics systems during the machines operation. To look for predictive characteristics just prior to a machine trip., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Currently there is an increasing interest in dielectric wall accelerators. These work by slowing the speed of an EM wave to match the velocity of a particle beam, allowing wave-beam interactions, accelerating the beam. However conventional dielectric materials have limited interaction regions, so wave-beam energy transfer is minimal. In this paper we consider Artificial Materials (AMs), as slow wave structures, in the presence of charged particle beams to engineer Inverse-Cherenkov acceleration. AMs are periodic constructs whose properties depend on their subwavelength geometry rather than their material composition, and can be engineered to give an arbitrary dispersion relation. We show that Metamaterials, one example of an AM, can mediate an Inverse-Cherenkov interaction, but break down in high power environments due to high absorption. We consider AMs with low constitutive parameters and show they can exhibit low absorption whilst maintaining the ability to have a user defined dispersion relation, and mediate a wavebeam interaction leading to Inverse-Cherenkov acceleration., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

We characterise the neutron flux and energy spectra produced by protons on a lead target. This may enable studies of the neutronics of an ADSR, to be separated from the higher energy spallation processes, in order to explore te potential of ADSR as a better alternative for energy production, safety and waste transmutation. We consider a range of proton energies, and show how the numbers of neutrons produced can be fitted by some simple functions of the proton energy, as can the spatial and energy distributions. These calculations were performed in both MCNPX and Geant4 and we compare and benchmark the low energy neutron spectra obtained by MCNPX code and a Monte Carlo Code Geant4 against each other. Discrepancies were found for the low energy neutron spectrum, but by using different models as calculation options for low energy neutrons in Geant4, this disagreement has been significantly reduced., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

A non-scaling fixed field alternating gradient (nsFFAG) accelerator is being designed for helium ion therapy. This facility will consist of 2 nested superconducting rings, treating with helium ions (He²⁺) and image with hydrogen ions (H²⁺). Compared to protons, ions deliver a more conformal dose with a significant reduction in range straggling and beam broadening. Carbon ions are currently used and there are no current facilities providing helium therapy. We are investigating the feasibility of an FFAG approach for helium therapy, which has never been previously considered. We investigate emittance and demonstrate that the machine meets isochronicity requirements for fixed frequency RF., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

In recent years there has been growing interest in the use of neutron scanning techniques for security. Neutron techniques with a range of energy spectra including thermal, white and fast neutrons have been shown to work in different\ud scenarios. As international interest in neutron scanning increases the risk of activating cargo, especially foodstuffs must be considered.\ud \ud There has been a limited amount of research into the activation of foods by neutron beams and we have sought to improve the amount of information available. In this paper we show that for three important metrics; Activity, Ingestion\ud Dose and Time to Background there is a strong dependence on the food being irradiated and a weak dependence on the energy of irradiation.\ud \ud Previous studies into activation used results based on irradiation of pharmaceuticals as the basis for research into activation of food. The earlier work reports that 24Na production is the dominant threat which motivated the search for 23(n;\gamma)24Na in highly salted foods. We show that 42K can be more significant than 24Na in low\ud salt foods such as Bananas and Potatoes.

The current reliance on X-Rays and intelligence for national security is insufficient to combat the current risks of smuggling and terrorism seen on an international level. There are a range of neutron based security techniques which have the potential to dramatically improve national security. Neutron techniques can be broadly grouped into neutron in/neutron out and neutron in/photon out techniques. The use of accelerator based fusion devices will potentially enable to wide spread application of neutron security techniques due to the potential for much safer operation than that offered by fission or sealed tube sources. In this paper we discuss some of the neutron security techniques available and the advantages they present., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

An experimental approach to verify the forward scattering sum rule for periodic structures is presented. This approach allows an upper bound on the total cross section integrated over a bandwidth from a simple static problem to be found. Based on energy conservation, the optical theorem is used to construct a relation between the total cross section and the forward scattering\ud of periodic structures as well as single scatterers inside a parallel plate waveguide. Dynamic measurements are performed using a parallel plate waveguide and a parallel plate capacitor is utilized to �find the static polarizability. Convex optimization is introduced to identify the total scattering in the dynamic\ud measurements. The results show that the all spectrum interaction between the electromagnetic �field and an object are proportional to the static polarizability of the object.

There is a growing interest in the use of neutrons for national security. The majority of work on security focuses on the use of either sealed tube DT fusors or fission sources, e.g. Cf-252. Fusion reactions enable the energy of the neutron beam to be chosen to suit the application, rather than the application being chosen based on the available neutron beam energy. In this paper we discuss simulations of fusion reactions demonstrating the broad range of energies available and methods for adapting the neutron beam energy produced by target/projectile combinations., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Neutrons are primarily produced at large international\ud facilities using either spallation reactions or nuclear fission.\ud There is a demand for small scale neutron production for\ud use at hospitals and borders for a variety of applications.\ud Isolated fission sources and sealed tube deuterium-tritium\ud fusors are able to provide a reliable neutron flux at small\ud scale but are impractical due to the associated radioactivity.\ud A beam of protons or deuterons accelerated onto a thin target\ud will undergo a fusion reaction resulting in the emission\ud of a quasi-monochromatic neutron beam. The total flux\ud and energy spectrum of the neutrons produced through fusion\ud is primarily dependent on target material, target thickness,\ud beam energy and projectile. The use of neutrons for\ud security screening at border crossings, ports and airports\ud has the potential to drastically improve threat detection and\ud contents verification. Monte Carlo code MCNPX is being\ud used to investigate the most suitable target and beam characteristics\ud for a neutron source for security applications.

The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since RS varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. Different models accounting for the field depended surface resistance are being confronted by the experimental results. The RF results are being correlated to surface analyses measurements carried out on the same samples

The surface resistance Rs of superconducting cavities can be obtained from the unloaded quality factor Q0. Since Rs varies strongly over the cavity surface its value must be interpreted as averaged over the whole cavity surface. A more convenient way to investigate the surface resistance of superconducting materials is therefore to examine small samples, because they can be manufactured cheaply, duplicated easily and used for further surface analyses. At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution, results from measurements on bulk niobium and niobium film on copper samples are presented. It is shown how different contributions to the surface resistance depend on temperature, applied RF magnetic field and frequency. Furthermore, measurements of the maximum RF magnetic field as a function of temperature and frequency in pulsed and CW operation are presented. The study is accompanied by measurements of the surface properties of the samples by various techniques

The status of PAMELA (Particle Accelerator for\ud MEdical Applications) – an accelerator for proton and light ion therapy using a non-scaling FFAG (ns-FFAG) accelerator – is reviewed and discussed.

In this paper we ex­am­ine the ef­fect of in­tro­duc­ing an Elec­tro­mag­net­ic meta­ma­te­ri­al into a Trav­el­ling Wave struc­ture to me­di­ate in­verse Cherenkov ac­cel­er­a­tion. Elec­tro­mag­net­ic meta­ma­te­ri­als are ar­ti­fi­cial ma­te­ri­als that con­sist of macro­scop­ic struc­tures that yield an ef­fec­tive per­mit­tiv­i­ty and per­me­abil­i­ty less than zero. The prop­er­ties of meta­ma­te­ri­als are high­ly fre­quen­cy de­pen­dent and give rise to very novel dis­per­sion re­la­tion­ships. We show that the in­tro­duc­tion of a specif­i­cal­ly de­signed meta­ma­te­ri­al into the in­ter­ac­tion re­gion gives rise to a novel dis­per­sion curve yield­ing a unique wave-par­ti­cle in­ter­ac­tion. We demon­strate that this novel wave-par­ti­cle in­ter­ac­tion gives rise en­er­gy ex­change from wave to beam over an ex­tend­ed in­ter­ac­tion regime. We also dis­cuss the ben­e­fits and is­sues that arise from hav­ing a meta­ma­te­ri­al in a high vac­u­um high power en­vi­ron­ment with a spe­cif­ic focus on the issue of loss in meta­ma­te­ri­al struc­tures.

The ever-growing demand for higher beam energies has dramatically increased the risk of RF breakdown, limiting the maximum achievable accelerating gradient. Field emission is the most frequently encountered RF breakdown where it occurs at regions of locally enhanced electric field. Electrons accelerated across the cavity as they tunnel through the surface in the presence of microscopic defects. Upon Impact, most of the kinetic energy is converted into heat and stress. This can inflict irreversible damage to the surface, creating additional field emission sites. This work aims to investigate, through simulation, the physics involved during both emission and impact of electrons. A newly developed 3D field model of an 805 MHz cavity is generated by COMSOL Multiphysics. Electron tracking is performed using a Matlab based code, calculating the relevant parameters needed by employing fourth Order Runge Kutta integration. By studying such behaviours in 3D, it is possible to identify how the cavity surface can alter the local RF field and lead to breakdown and subsequent damages. The ultimate aim is to introduce new surface standards to ensure better cavity performance., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

The possibility of achieving higher accelerating\ud gradients at higher frequencies with the reduction of the\ud effect of HOMs, compared to conventional accelerating\ud structures, is increasing interest in the possible use of\ud Photonic Crystals (PC) for accelerator applications. In\ud this paper we analyze how the properties of the lattice of a\ud PC resonator can be engineered to give a specific band\ud structure, and how by tailoring the properties of the lattice\ud specific EM modes can either be confined or moved into\ud the propagation band of the PC. We further go on to\ud discuss the role of disorder in achieving mode\ud confinement and how this can be used to optimize both\ud the Q and the accelerating gradient of a PC based\ud accelerating structure. We also examine the use of high\ud disorder to give rise to Anderson Localization, which\ud gives rise to exponential localization of an EM mode.\ud Discussing the difference between the extended Bloch\ud wave, which extends over the entire PC, and the Anderson\ud localized mode.