First measurements with the Munich 2D-ACAR spectrometer on Cr

TL;DR

This paper introduces the first measurements using the new Munich 2D-ACAR spectrometer on chromium, demonstrating its capabilities across different temperatures and magnetic phases.

Contribution

The paper presents the design, features, and initial measurements of the Munich 2D-ACAR spectrometer, showcasing its application to chromium at various temperatures.

Findings

Successful operation of the new 2D-ACAR spectrometer

First measurements on Cr at different magnetic phases

Data collected at 5K, room temperature, and 318K

Abstract

The Munich 2D-ACAR spectrometer at the Maier-Leibnitz accelerator laboratory in Garching has recently become operational. In the present implementation a 2D-ACAR spectrometer is set up, with a baseline of 16.5m, a conventional 22Na positron source and two Anger-type gamma-cameras. The positrons are guided onto the sample by a magnetic field generated by a normal conducting electromagnet. The sample can be either cooled by a standard closed-cycle-cryostat to low temperatures or heated by a resistive filament to temperatures up to 500K. We present the key features of this new 2D-ACAR spectrometer and, in addition, discuss first measurements on the pure metal system Cr. The 2D-ACAR measurements have been performed on Cr at different temperatures: at 5K and at room temperature in the anti-ferromagnetic phase and at 318K slightly above the paramagnetic phase transition.