Topology optimization in the framework of the linear Boltzmann equation – a method for designing optimal nuclear equipment and particle optics

International audienceIn this study, we describe a procedure of topology optimization in the framework of the linear Boltzmann equation, implemented using the reference Monte-Carlo particle transport code MCNP. This procedure can design complex structures that optimize the transport of particles, according to preset objectives and constraints. Although simple and perfectible, this procedure has been successfully tested on a series of difficult problems, with results outperforming human capabilities. Improved, it could be used to assist or automate the design of particle optics or nuclear devices

A TOPOLOGY OPTIMIZATION PROCEDURE FOR ASSISTING THE DESIGN OF NUCLEAR COMPONENTS

In this paper, we show that a module implemented in the MCNP transport code to perform sensitivity analyses can be diverted to perform topology optimizations of nuclear equipment. Component design with this approach leads to sophisticated solutions that outperform their human-designed counterparts

Topology optimization design of the "Beam Shaping Assembly" of an AB-BNCT facility - application to the case of glioblastoma treatment

Objective. This study aims to determine the optimal structure of the Beam Shaping Assembly (BSA) for an AB-BNCT (Accelerator-Based Boron Neutron Capture Therapy) facility. The aim is to maximize the possible depth of treatment for glioblastoma while ensuring that a treatment time constraint is not exceeded.Approach. To achieve this goal, we utilize a new optimization procedure known as topology optimization. This technique can accurately identify the most optimal structure of a nuclear device, in this case a BSA, to be identified among 9×10^1206 possible structures for the example given in this study. The exploration of such a vast space of configurations is inaccessible to any other method available to date.Main results. The topology optimization generated Air-AlF3-LiF-LiFPE BSA has an original structure that differs significantly from the structures previously tested by the BNCT community. This structure generates unprecedented treatment depths, with a Treatable Depth TD = 10.08 cm and an Advantage Depth AD = 12.76 cm (for 15 ppm of Boron-10 in blood, with a 3.5 tumor-to-blood Boron-10 concentration ratio), or TD = 10.61 cm and AD = 13.14 cm (for 18 ppm of Boron-10), much greater than any other design proposed to date by the community.Significance. The findings of this study indicate that topological optimization procedures are highly beneficial for the design of BSAs, resulting in a significant qualitative improvement

Topology optimization design of the "Beam Shaping Assembly" of an AB-BNCT facility - application to the case of glioblastoma treatment

Objective. This study aims to determine the optimal structure of the Beam Shaping Assembly (BSA) for an AB-BNCT (Accelerator-Based Boron Neutron Capture Therapy) facility. The aim is to maximize the possible depth of treatment for glioblastoma while ensuring that a treatment time constraint is not exceeded.Approach. To achieve this goal, we utilize a new optimization procedure known as topology optimization. This technique can accurately identify the most optimal structure of a nuclear device, in this case a BSA, to be identified among 9×10^1206 possible structures for the example given in this study. The exploration of such a vast space of configurations is inaccessible to any other method available to date.Main results. The topology optimization generated Air-AlF3-LiF-LiFPE BSA has an original structure that differs significantly from the structures previously tested by the BNCT community. This structure generates unprecedented treatment depths, with a Treatable Depth TD = 10.08 cm and an Advantage Depth AD = 12.76 cm (for 15 ppm of Boron-10 in blood, with a 3.5 tumor-to-blood Boron-10 concentration ratio), or TD = 10.61 cm and AD = 13.14 cm (for 18 ppm of Boron-10), much greater than any other design proposed to date by the community.Significance. The findings of this study indicate that topological optimization procedures are highly beneficial for the design of BSAs, resulting in a significant qualitative improvement

Optimal heavy water neutron moderators for an AB-BNCT treatment unit

In this study, we use a topology optimization algorithm, developed at the CNRS LPSC, to design a heavy-water neutron moderator for a BNCT treatment unit. The solutions generated by this algorithm are compact yet succeed in limiting the exposure of patient’s healthy tissues to levels below recommended limits. They present subtle, original geometries inaccessible to standard design techniques. The versatility of this novel approach makes it possible to automate the moderator design, and fit it to the configuration of the BNCT unit considered, e.g. the neutron source and materials it uses or the room it occupies, as well as to the biological parameters of its patients, e.g. the volume and depth of the tumor to be treated or the characteristics of the targeted organs

Optimal heavy water neutron moderators for an AB-BNCT treatment unit

In this study, we use a topology optimization algorithm, developed at the CNRS LPSC, to design a heavy-water neutron moderator for a BNCT treatment unit. The solutions generated by this algorithm are compact yet succeed in limiting the exposure of patient’s healthy tissues to levels below recommended limits. They present subtle, original geometries inaccessible to standard design techniques. The versatility of this novel approach makes it possible to automate the moderator design, and fit it to the configuration of the BNCT unit considered, e.g. the neutron source and materials it uses or the room it occupies, as well as to the biological parameters of its patients, e.g. the volume and depth of the tumor to be treated or the characteristics of the targeted organs

Heavy-water-based moderator design for an AB-BNCT unit using a topology optimization algorithm

International audienceObjective. The design of neutron moderators for BNCT treatment units currently relies on parametric approaches, which yield quality results but are ultimately limited by human imagination. Efficient but non-intuitive design solutions may thus be missed out. This limitation needs to be addressed. Approach. To overcome this limitation, we propose to use a topology optimization algorithm coupled with a state-of-the-art Monte-Carlo transport code. This approach recently proved capable of finding complex optimal configurations of particle propagators with limited human intervention. Main results. In this study, we apply this algorithmic solution to optimize some heavy-water neutron moderators for a specific AB-BNCT treatment unit. The moderators thus generated are compact yet succeed in limiting the exposure of patient’s healthy tissues to levels below recommended limits. They present subtle, original geometries inaccessible to standard parametric approaches or human intuition. Significance. This approach could be used to automatically fit the design of a BNCT moderator to the location and shape of the tumor or to the morphology of the patient to be treated, opening a path for more targeted BNCT treatment

Optimization of in-target yields for RIB production - Part I: Direct yields

In-target yields for different configurations of thick direct targets

The source jerk integral method for sub-critical measurements in ADS

ISBN 978-1-5272-6447-2International audienceThree sub-critical (SC) core configurations were investigated in the VENUS-F zero power reactor coupled with the GENEPI-3C accelerator. The SC10 and SC12 were a mock-up of a MYRRHA start-up core and SC11 represented a more complex MYRRHA core loaded with various types of in-pile-sections. The sub-criticality of 11 variants of these VENUS-F cores was changed in several steps from -6$down to -30$ using the safety and control rods. Their sub-criticalities were determined with the Source Jerk Integral (SJI) method using 11 fission chambers located all over the reactor. For the data analysis, the 8-group delayed neutron parameters from the JEFF-3.1.2 evaluated nuclear data library were used. Reliability and reproducibility of the experimental results were tested by repeating the measurements, swapping the detectors and varying the accelerator beam intensity, thus changing the detector count rates and verifying the validity of the dead time corrections. The obtained results are compared with MCNP calculations