Glossary

accumulation threshold

The value above which contiguous regions with at least the required points detections are summed.

diameter

Reference particle diameter. Must be determined externally.

density

Particle density. Must be measured externally or assumed for a certain material. The Density Database contains the density for several hundred materials.

detection threshold

The value above which a signal is considered a detection (particle). This is also called the critical value in Poisson statistics.

event time

The acquisition time of a single event, also known as the dwell time. The eventtime is set during data import and cannot be edited.

error rate

Determines the number of false detections, i.e. background signal incorrectly identified as particles. An error rate (\(\alpha\)) of \(10^(-6)\) corresponds to 1 false detection per 1 million events.

ionic response

The signal produced per mass of material. Measured by collecting one or more ionic standards of known concentrations. The ionic response can be calibrated from multiple standard levels using the Ionic Response Calculator.

isotope expression

A mathmatical operation on one or more isotopes. These are usually made using the Signal Calculator. For most purposes, these are treated as a normal isotope.

mass fraction

The amount of measured material per total particle. If an AuAg particle is 40 % Au by mass, then the mass fraction for Au will be 0.4 and 0.6 for Ag. The Mass Fraction Calculator can calculate the mass fraction from a known molecular formula.

mass response

An alternate calibration strategy. The mass response uses the average mass of a reference particle to calibrate signal into mass.

molar mass

The molecular weight of the particle material. Formally used to calculate intracellular concentrations, now depreciated.

required points

The number of points in a consecutive regions that must be above the detection threshold to be cconsidered a detection. Added in version 1.2.10.

required prominence

The minimum peak prominence (smallest height from the peak edge) conjoined peaks must have before being separated. This is expressed as a percentage of the tallest peak.

single ion area

The distribution created by single ion events for detectors unable to operate in a pulse counting mode, e.g., ToF. The mean of this distribution is used to convert raw detector values into counts. The distribution is mass dependent and is sampled for compound Poisson thresholding.

transport efficiency

The fraction of material that is successfully transported to the detector. Typically 0.02 - 0.1 (2 - 10%).

uptake

The sample flow rate. This can be measured gravimetrically, via the change in sample mass over a fixed time.