Cryogenic micro-calorimeters for mass spectrometric identification of neutral molecules and molecular fragments

TL;DR

This study demonstrates the use of cryogenic micro-calorimeters for high-resolution mass spectrometry of neutral molecules and fragments, achieving precise energy measurements and identifying molecular products.

Contribution

It introduces a systematic investigation of MMC energy resolution for atomic and molecular projectiles and demonstrates neutral molecule identification capabilities.

Findings

Achieved energy resolutions down to 120 eV for atoms

Successfully identified neutral molecular fragmentation products

Showed that backscattering dominates energy spread and can be mitigated

Abstract

We have systematically investigated the energy resolution of a magnetic micro-calorimeter (MMC) for atomic and molecular projectiles at impact energies ranging from $E\approx13$ to 150 keV. For atoms we obtained absolute energy resolutions down to $\Delta E \approx 120$ eV and relative energy resolutions down to $\Delta E/E\approx10^{-3}$. We also studied in detail the MMC energy-response function to molecular projectiles of up to mass 56 u. We have demonstrated the capability of identifying neutral fragmentation products of these molecules by calorimetric mass spectrometry. We have modeled the MMC energy-response function for molecular projectiles and conclude that backscattering is the dominant source of the energy spread at the impact energies investigated. We have successfully demonstrated the use of a detector absorber coating to suppress such spreads. We briefly outline the use of MMC detectors in experiments on gas-phase collision reactions with neutral products. Our findings are of general interest for mass spectrometric techniques, particularly for those desiring to make neutral-particle mass measurements.