Calculators & Reference Tools

Quadrupole & RF Calculators

Practical design tools for the mass spectrometry community. Compute RF and DC operating voltages, visualize Mathieu stability regions, and plan mass scan parameters for quadrupole mass filters driven by GAA RF systems.

RF & Quadrupole

Quadrupole Mass Filter — RF / DC Calculator

Calculate RF amplitude (V₀), DC voltage (U), and Mathieu parameters for a quadrupole mass filter. The stability diagram is computed via RK4 numerical integration of the Mathieu equation — the same physics used in commercial instruments.

RK4 Integration Mathieu Equation First Stability Region

Field radius r₀ millimetres

Drive frequency f Hz — e.g. 1000000 for 1 MHz

Target m/z Daltons (unified atomic mass units)

Resolution mode

Operating point: stable

RF amplitude V₀

—

Volts (0-to-peak)

DC voltage U

—

Volts

V₀ peak-to-peak

—

Volts (p-p)

Mathieu q

—

Mathieu a

—

a/q ratio

—

Mathieu stability diagram — computed via RK4 integration of the Mathieu equation

Computing…

m/z sweep — RF and DC voltages across mass range

Start m/z

Stop m/z

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Driving a quadrupole with GAACE hardware? The MIPS RF Quad module and standalone RF Generator are designed to operate at the voltages this calculator produces. For custom frequency or voltage ranges, contact us — we configure systems to your exact geometry.

RF Circuit Design

RF Resonant Circuit — LC, Coil & Reactance Calculators

Four linked tools for designing the LC tank circuits used in quadrupole RF drivers, ion guides, and RF traps. Solve for any LC parameter, design your coil geometry using Wheeler's formula, look up wire gauge specifications, and calculate the RF currents and voltage stress at resonance. All tools are interconnected — changing the coil design automatically updates the frequency and current calculations.

Wheeler Formula LC Resonance AWG Reference Reactance & Current

1 — LC Resonant Frequency Solve any unknown

f = 1 / (2π√LC) · select which parameter to calculate

Frequency f

MHz

Inductance L

µH

Capacitance C

Resonant frequency

—

MHz

Angular frequency ω

—

Mrad/s

Period T

—

µs

2 — Air-Core Coil Inductance Wheeler's Formula

L(µH) = r²·N² / (9r + 10ℓ) [r and ℓ in inches] — single-layer air-core coil

Coil diameter

mm (outside diameter)

Winding length

Number of turns N

total turns

Inductance L

—

µH

Required TPI

—

turns / inch (close-wound)

Pitch per turn

—

mm / turn

3 — Reactance & RF Currents at Resonance X = ωL = 1/ωC

At resonance X_L = X_C. Circulating current I = V / X_L. Capacitor stress V_C = I · X_C.

Frequency f

MHz

Inductance L

µH

RF voltage across load

V (0-to-peak)

Circuit Q factor

typical 20–200 for mass spec RF

Coil DC resistance R_dc

Ω — measure with DMM

Reactance X_L = X_C

—

Circulating current I

—

A (0-to-peak)

Resistive power loss P

—

Capacitor voltage V_C

—

V (0-p) — check rating!

Resonant capacitance

—

Driver voltage needed

—

V (0-p) into tank

4 — Wire Gauge Reference Table AWG · TPI · resistance

Turns per inch assumes close-wound (no gap). For spaced winding, actual TPI will be lower. Coil calculator required TPI: — — best-fit gauge highlighted below.

AWG	Bare dia. (mm)	Insul. dia. (mm)	TPI close-wound	Resist. (Ω/m)	Max I (A)	Notes

* Max current ratings are conservative guidelines for chassis wiring. At RF frequencies skin effect increases effective resistance — use heavier gauge or silver-plated wire for high-Q coils.

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Using GAACE RF hardware? The RF Generator and RF Mega heads are designed to drive resonant loads in the range these calculators produce. For help matching a coil to your specific quadrupole geometry or load capacitance, contact us.

Ion Optics

Ion Kinetic Energy Calculator

Calculate ion velocity, accelerating voltage, or kinetic energy from mass and charge state. Also computes center-of-mass collision energy for CID experiments — the energy that actually goes into bond breaking when an ion hits a neutral gas molecule.

KE = z·e·V = ½mv² CID collision energy Solve any unknown

Select what to calculate

Ion mass m

Daltons (Da / u)

Charge state z

integer (1, 2, 3 …)

Accelerating voltage V

Volts

Ion velocity v

m/s

pad

KE = z·e·V = ½·m·v²
v = √(2·z·e·V / m)

Velocity

—

m/s

Kinetic energy

—

Velocity (mm/µs)

—

mm/µs — useful for TOF

v/c (relativistic check)

—

fraction of speed of light

Center-of-mass collision energy (CID)

E_CM = E_lab × M_gas / (M_gas + M_ion) — the fraction of lab-frame energy available for bond breaking.

Collision gas

Custom gas mass (if selected above)

Da — overrides dropdown if "Custom" selected

E_CM collision energy

—

E_lab (ion KE)

—

E_CM / E_lab ratio

—

efficiency of energy transfer

Switched Ion Optics

Capacitive Load Power Calculator

Every time a switched voltage is applied to a capacitive load — an electrode, ion gate, or detector — charge must flow to change the voltage. At high switching rates this constitutes a continuous power draw even though no DC current flows through the load. This calculator quantifies load power, peak current, energy per cycle, and driver thermal stress for square wave, sinusoidal, and trapezoidal waveforms. Essential for selecting FET switches, sizing power supplies, and understanding why high-frequency switching of large electrode arrays demands surprisingly large power budgets.

P = C·ΔV²·f Square / Sine / Trap FET switch sizing Multi-channel arrays

Square wave

Voltage switches abruptly between two levels. Each transition moves Q = C·ΔV in a short rise time, producing a large current spike. Power scales linearly with frequency. Ion gates, Bradbury-Nielsen gates, deflectors, trap switching.

Sinusoidal

Current leads voltage by 90° — the load is purely reactive. Power delivered continuously rather than in spikes. FAIMS asymmetric waveforms, RF ion guide drive monitoring, AC-coupled electrode systems.

Trapezoidal

Square wave with finite, controllable rise/fall times and adjustable duty cycle. More realistic for real driver outputs. Peak current set by ΔV/t_rise. TWAVE electrodes, SLIM switching arrays, shaped pulse ejection.

Ion gate / deflector10–100 pF, 100–500 V, 1–100 kHz. Peak currents of 0.1–5 A are common.

TWAVE electrode arrayMany electrodes in parallel multiply total C. Use channel count to see full supply burden.

SLIM deviceHundreds of electrodes × tens of pF. Total load can reach nF at MHz rates.

FAIMS waveformAsymmetric high-voltage sine at 1–5 MHz. Sinusoidal mode gives the correct estimate.

FET switch selectionI_pk sets minimum FET I_D rating. R_on×I_pk² determines device heating.

Supply sizingTotal supply current (all channels, with efficiency) sets minimum supply current rating.

Waveform type

P = C · ΔV² · f | I_pk = C · ΔV / t_rise | E_cycle = C · ΔV²

Load parameters

Capacitance C

pF — measure with LCR meter or estimate from geometry

Voltage swing ΔV

V — full swing (square/trap) or 0-to-peak amplitude (sine)

Frequency f

Hz — switching rate or drive frequency

Rise / fall time t_r

Driver parameters

Driver on-resistance R_on

Ω — FET R_DS(on) or output impedance

Supply voltage V_supply

V — DC rail voltage

Driver efficiency η

% — typical FET driver 80–95%

Number of channels

multiply for electrode arrays — TWAVE, SLIM, ion funnels

Results — per channel & total

Load power P

—

W per channel

Total load power

—

W (all channels)

Supply current

—

A from supply

Peak current I_pk

—

A into cap during rise

Energy per cycle

—

Driver dissipation

—

W in R_on

Charge per cycle Q

—

Avg charge current

—

A average

Calculating…

Waveform preview — voltage and current vs time (one cycle)

Power vs frequency — log scale · red dot = current operating point

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Switching ion optics with GAACE hardware? The FET switch, TWAVE driver, and FAIMS electronics in the MIPS platform are designed to drive the capacitive loads this calculator describes. For help matching a driver to your electrode geometry and switching requirements, contact us.

Reference Resources

Useful Links & Resources

Curated links for the mass spectrometry research community — data references, open-source software, simulation tools, and key literature resources.

⚓ Data & Databases

Chemistry Reference

NIST Chemistry WebBook

The definitive reference for exact masses, isotope patterns, molecular formulas, and thermochemical data. Essential for mass calibration and peak identification.

webbook.nist.gov/chemistry

Proteomics

UCSF Protein Prospector

Web-based tools for protein and peptide mass calculations, fragment ion prediction, and database searching. Widely used for bottom-up proteomics workflows.

prospector.ucsf.edu

Ion Mobility / CCS

CCSbase / CollisionDB

Community database of experimental collision cross section (CCS) values for small molecules and peptides across multiple instrument platforms and buffer gases.

collisiondb.ca

Lipids

LIPID MAPS

Comprehensive lipid structure database with exact masses, MS/MS fragmentation data, and pathway tools. The reference standard for lipidomics research.

lipidmaps.org

Literature Search

PubMed

Free full-text archive and search engine for biomedical and life sciences literature maintained by the NIH National Library of Medicine. The primary resource for finding mass spectrometry methods papers, instrumentation articles, and application studies.

pubmed.ncbi.nlm.nih.gov

💻 Open-Source Software

Data Processing

mMass

Free, open-source mass spectrum interpreter for Windows and macOS. Excellent for manual spectrum annotation, isotope pattern matching, and sequence analysis.

mmass.org

Ion Mobility / CCS

CIUSuite 2

Open-source software for collision-induced unfolding (CIU) data analysis. Fingerprinting, classification, and comparison of protein CIU datasets from IM-MS instruments.

github.com/bhattlab/CIUSuite2

CCS Calculation

IMoS / MOBCAL

Computational tools for calculating theoretical CCS values from molecular structures using trajectory (TM), projection approximation (PA), and EHSS methods.

github.com — IMoS2 / MOBCAL

Instrument Control

GAA GitHub Repository

Open-source firmware, Arduino libraries, and control software for MIPS and associated GAA Custom Electronics hardware. Actively maintained with community contributions welcome.

github.com/GordonAnderson

Multi-Tool Suite

PNNL Computational Mass Spectrometry

A suite of open-source tools developed at Pacific Northwest National Laboratory covering proteomics, metabolomics, data processing, and instrument control. Includes MASIC, DeconTools, Protein Digestion Simulator, and many others widely used in the mass spec community.

pnnl-comp-mass-spec.github.io

🔬 Simulation Tools

Ion Optics Simulation

SIMION

The industry-standard ion trajectory simulation software. Models electrostatic and magnetic fields, ion optics, and mass analyzer geometries. Used by instrument designers worldwide.

simion.com

RF Ion Trap Simulation

ITSIM / Ion Simulation

Simulation environment specifically designed for ion trap mass spectrometers. Models ion motion in RF fields, space charge effects, and resonance ejection.

ionsimulation.com

Molecular Dynamics

GROMACS

High-performance molecular dynamics package widely used for native MS and ion mobility structure prediction. Free and open source with excellent GPU support.

gromacs.org

Electronics Simulation

LTspice

Free SPICE-based circuit simulator from Analog Devices. Invaluable for designing RF driver circuits, FET switch networks, and power supply topologies for mass spec electronics.

analog.com — LTspice

📖 Key Journals & Literature

Primary Journal

Journal of the American Society for Mass Spectrometry (JASMS)

The leading mass spectrometry journal covering instrumentation, methodology, and applications. Published by the American Society for Mass Spectrometry.

pubs.acs.org/journal/jasms

Broad Analytical

Analytical Chemistry (ACS)

High-impact journal covering the full range of analytical methods including mass spectrometry, ion mobility, and related detector technologies. Biweekly publication.

pubs.acs.org/journal/ancham

Rapid Communication

Rapid Communications in Mass Spectrometry

Fast-track publication for new MS techniques, instrumentation innovations, and novel applications. Good source for emerging ion mobility and native MS developments.

Wiley — Rapid Commun. Mass Spectrom.

Community

American Society for Mass Spectrometry (ASMS)

Professional society hosting the annual ASMS conference — the largest gathering of mass spectrometrists worldwide. Resources include short courses, job postings, and the MS education portal.

asms.org

Coming Soon

More Tools In Development

Additional calculators are being developed for the mass spectrometry community. Check back regularly or contact us to request a specific tool.

📐

K₀ / CCS Converter

Convert between drift time, reduced mobility K₀, and collision cross section (Å²) for ion mobility measurements. Supports He, N₂, and Ar buffer gases.

Ion Mobility

🔁

Ion Trap Parameter Calculator

Calculate trapping RF amplitude, secular frequency, and pseudopotential well depth for a Paul trap from r₀, z₀, and drive frequency.

Ion Traps

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FET Pulser Rise Time Calculator

Estimate rise and fall times from load capacitance and drive resistance. Directly applicable to GAACE FET switch and pulser products (10–15 ns typical).

Electronics

🔍

Resolving Power Calculator

Calculate mass resolving power R = m/Δm and peak width from measured spectra, for both quadrupole and time-of-flight analyzers.

Mass Analysis

Engineering Tools
for Mass Spec Research

Quadrupole & RF Calculators

Useful Links & Resources

More Tools In Development

Help Us Build a Better
Toolbox

Engineering Toolsfor Mass Spec Research

Quadrupole & RF Calculators

Useful Links & Resources

More Tools In Development

Help Us Build a BetterToolbox

Engineering Tools
for Mass Spec Research

Help Us Build a Better
Toolbox