Development of a muon-rejection system for the nuclear-reaction analysis station at the Tandem Laboratory

Background

Ion beam analysis techniques allow for non-destructive studies on near surface hydrogen. Resonant nuclear reaction analysis (NRA), based on the 1H(15N,αγ)12C nuclear reaction, with its cross section exhibiting a narrow resonance (Γ=1.8 keV) at 6.385 MeV, is commonly employed for precise, in-depth, quantification of hydrogen concentrations. The Tandem Laboratory at Uppsala University, employs a resonant-NRA setup that is in regular use. As resonant-NRA relies on the detection of γ-rays emitted from the sample, measurements are subject to the natural background present in any laboratory environment. Fortunately, the high energy of the γ-ray line of interest, separates it well from the majority of lines originating from common radioisotopes. Interference from cosmic-ray muons, however, is still a problem.

Project goal and work plan

The NRA setup at the Tandem Laboratory is currently being upgraded and, as part of this upgrade, the addition of a muon-rejection system is desired to reduce the signal background and improve detection limits. The goal of the project will be to build this system. The project can be divided into the following key tasks:

• build a muon-detection system based on coincident-signal detected in two scintillation detectors;
• combine the system with the NRA station in anti-coincidence to reject muon events registered during measurement;
• quantitively assess the background rejection properties of the system, and the improvement in hydrogen detection-limit it brings;
• further optimise the system based on the results obtained;
• write a report summarizing the results and conclusion of the work.

The position will be based at the Ångström laboratory in Uppsala, within the Ion-physics Group. This project provides an excellent opportunity to become acquainted with the broad range of research being conducted within the Ion-physics group, and to make a long-standing contribution to its operation.

The project can be adjusted to correspond to 15, 30 or 45 ECTS credits and can start during either the autumn 2023, or spring 2024 semesters.

Desired qualifications/experience

The applicant should be enrolled on a physics program at Uppsala University and possess:

• good practical abilities
• a strong interest in experimental work;
• excellent skills in both written and spoken English;
• knowledge/training in Nuclear Physics will be advantageous.

Students seeking diploma-work projects at both Master and Bachelor level are encouraged to apply, as are students seeking project work for courses (but such projects must correspond to at least 15 credits). The possibility of paired or group work can be discussed.

For further information please contact:

Robert Frost rob.frost@physics.uu.se