Design of an integrated graphite collimator for PTF targets

SCK•CEN Mentor

Houngbo Donald, dhoungbo@sckcen.be, +32 (0)14 33 34 65

Expert group

Proton Target Research

Introduction

The Belgian Nuclear Research Centre is developing the multi-purpose irradiation facility MYRRHA, a flexible fast spectrum research infrastructure conceived as an Accelerator Driven System (ADS). It consists of a  600 MeV proton linear accelerator (linac) which drives a lead-bismuth cooled sub-critical reactor. According to the MYRRHA phased implementation plan, a first facility will be constructed at SCK•CEN in Mol, composed of a 100 MeV proton linac coupled to a Proton Target Facility. This facility, contains an Isotope Separation On-Line (ISOL) target station for fundamental research and for the production of medical radioisotopes as well as a target station for fusion material research. In the ISOL facility, isotopes are produced in thick targets via proton-induced reactions, and delivered to experiments in the form of radioactive ion beams (RIB).

The design of the ISOL targets at the core of the Proton Target Facility is faced with exciting challenges owing to a unique combination of proton beam intensity, energy, and design objectives. One such interesting challenge concerns the design of an integrated collimator downstream of the actual ISOL target.

At ISOL facilities operating with a high energy proton beam the dump for the residual beam is located 0.6 ~2 m downstream of the target. At PTF, due to a relatively low energy of the protons in the first phase of the project, the residual beam downstream of the actual target is significantly scattered. Merely applying the same approach as the high energy facilities would result in large transverse dimensions for components such as gate valves, windows and high voltage insulators located in-between the target and the proton beam dump. Besides, the strategy of fully integrating the beam dump in the target, that is fit for ISOL facilities operating with a low energy proton beam, is not applicable either due to the high power of the proton beam at PTF. The proposed solution is that of an integrated collimator that acts as a beam dump in the tail of the transverse distribution of the residual beam.

The objective of this master thesis topic is to conduct design calculations for such a graphite collimator suited for carbide targets.

Objective

  • Run thermal simulations of beam-induced temperature distributions in the collimator during operation of the reference target.
  • Thermally optimize the design of the collimator to achieve the required transverse size reduction of the residual beam.
  • Run structural analysis of the collimator under beam-induced thermal stresses.
  • Evaluate the sensitivity to target thickness of both the beam-induced temperature distribution and the shape of the residual beam.
  • Evaluate the sensitivity to target material of both the beam-induced temperature distribution and the shape of the residual beam
  • Propose a mounting and assembling solution for the graphite collimator.

The minimum diploma level of the candidate needs to be

Academic bachelor

The candidate needs to have a background in

Electromechanics , Physics