OrbiSIMS community resources

NPL is the UK's National Metrology Institute, developing and maintaining the national primary measurement standards. The National Centre of Excellent in Mass Spectrometry Imaging (NiCE-MSI) at NPL and collaborators introduced OrbiSIMS in 2017 for 3D chemical imaging of molecules and it has become increasingly popular for biological and material sciences owing to its ability to give simultaneous high confidence in molecular identity and localisation.

With a growing number of instruments internationally, there is an increased need for reproducible measurements. In recent works we realised that Signal, Noise and Transmission form a metrology triangle that can provide a secure foundation and lead to innovative analytical methods and new technologies.

OrbiSIMS is done on a hybrid instrument with a dual analyser instrument combining a Time-of-Flight (ToF) mass spectrometer (MS) and an Orbitrap^TM MS, which confer advantages of speed and high-performance mass spectrometry, respectively. The VAMAS TWA 2 A37 MS interlaboratory comparison aims to build on the methods previously published and study reproducibility of OrbiSIMS experiments for organic and inorganic materials.

Benefits for participating in the intercomparison:

• Repeatability measured

• Noise characteristics measured

• Conversion factor of Orbitrap intensity to counts

• Signal linearity of instrument

• Reproducibility of relative and absolute signal

​Transmission

Recently we conducted a systematic study of two key parameters in OrbiSIMS transfer optics. The Orbitrap requires ions to have a potential of approximately 57.5 V and lower kinetic energy distribution than results from the SIMS process. The sample is biased by a sample target voltage, V_T, necessary to match the acceptance window of the Orbitrap^TM analyser. A transfer system using an ion guide with He gas at a pressure P slows the ions and reduces their kinetic energy distribution through inelastic collisions with gas atoms. The data acquired using the protocol will be used to map secondary ion intensity in function of V_T and P.

Noise and signal

Measurement of the Orbitrap^TM analyser noise distribution requires a source of ions that is stable over the time frame of the measurements. The protocol describes how to perform simple measurements of a reference silver sample across a range of ion intensities, beam currents and how to measure stability of the primary ion beam current at the sample.

Find out about our OrbiSIMS research

For more information contact Gustavo F. Trindade