4096 Channel Spectrum Support

13 min

AMICS 5.1 and newer support 4096-channel EDS spectra natively, matching the full resolution of modern Bruker EDS detectors. This doubles the spectral resolution compared to AMICS 3.x (2000 channels), improving material identification and classification accuracy.

What Changed

Property	AMICS 3.x	AMICS 5.1+
Default channel count	2000	4096
Energy per channel	10 eV	~5 eV (5.005 eV)
Spectrum data type	DWORD	uint32_t (xray_t)
Channel count per measurement	Fixed	Dynamic (stored in MRE Settings table)
Reference spectra resolution	2000	4096

Because each channel now covers about half the energy, the same channel number means a different energy in AMICS 3.x and AMICS 5. Anything saved as an energy (keV or eV) carries over unchanged. Anything saved as a channel number must be checked; see Spectrum Tree Workflows below.

Upgrading from AMICS 3.x — Checklist

Warning: Work through these steps the first time you run AMICS 5 on data, references or workflows from AMICS 3.x.

Back up your reference library before installing: UserSTD.db (SEM) and UserSTD_M4.db (M4)

Convert the reference library when AMICS first starts — answer Yes (see Converting the Reference Library below)

Convert measurements you want to match against 4096-channel references (see Converting Measurements below)

Re-enter channel ranges in Spectrum Tree workflows that use Ratio, Count or Total Count Clustering (see Spectrum Tree Workflows below)

Check results by classifying a well-known sample and comparing with your AMICS 3.x results

Converting the Reference Library

The first time AMICS 5 starts on a PC that has an AMICS 3.x reference library (UserSTD.db or UserSTD_M4.db) but no 4096-channel library yet, it asks:

"Do you want to convert legacy global UserSTD db to a new format?"

Yes — AMICS creates UserSTD.4096.db (and UserSTD_M4.4096.db for M4) with every reference spectrum converted to 4096 channels. Your custom references and workflows are kept.

No — AMICS uses the default reference library that ships with AMICS 5 instead. Your AMICS 3.x custom references are not carried over.

The question is asked separately for the SEM and M4 libraries, and only once: after the 4096-channel library exists, AMICS does not ask again. The original 3.x files are left in place.

Important: If you answered No by mistake, contact [email protected] before adding new references, so the conversion can be redone from your original UserSTD.db.

If your site uses a custom reference library file (set in preferences instead of the default location), AMICS checks that file's version and asks the same question before converting it in place. Back it up first.

Opening Legacy Measurements

AMICS 5 can open and analyze 2000-channel measurement files without converting them. Conversion is only needed if you want to match them against 4096-channel reference spectra.

Converting Measurements (2000 → 4096)

Conversion on File Open

When you open a measurement file with 2000-channel spectra:

AMICS detects the legacy format automatically

A dialog appears: "The measurement you're trying to open has legacy spectra format. Would you like to clone and convert the measurement to a new format?"

If you click Yes, AMICS creates a converted copy in a Converted_4096 subfolder (the original file is unchanged)

After conversion, choose:

Not Open — conversion complete, don't open the file

Open In This — open the converted file in the current AMICS instance

Open In Other — open in a new AMICS instance

If you click No, the file opens in its original 2000-channel format

Note: The original file is never modified. Conversion creates a clone in [original_folder]/Converted_4096/.

Batch Conversion

To convert an entire project of legacy measurements:

Open Batch Process...

Select all measurements in the project

Enable 2000 → 4096 conversion

Optionally enable reclassification to immediately reclassify with 4096-channel data

Click Start

See [Reclassification - Batch Processing] for the other batch options.

Conversion Algorithm (PCHIP)

AMICS uses PCHIP (Piecewise Cubic Hermite Interpolating Polynomial) interpolation to upsample 2000-channel spectra to 4096 channels:

PCHIP preserves the shape of peaks without introducing oscillation artifacts

The interpolation respects the monotonicity of the original data

Peak positions and relative intensities are maintained

The conversion is applied to both measurement spectra and any embedded reference spectra

Important: Interpolation cannot add detail that was not measured. A converted spectrum has 4096 channels, but its true resolution is still that of the original 2000-channel measurement. Keep your original files — they are the only copy of the data as measured.

Spectrum Tree Workflows

Spectrum Tree binning criteria are saved with the workflow. Some are saved as energies and some as channel numbers:

Binning criterion	Saved as	Action after upgrading from 3.x
Energy Filtering	keV / eV	None — carries over correctly
Ratio Clustering	Channel ranges	Re-enter both ranges
Count Clustering	Channel ranges	Re-enter the ranges
Total Count Clustering	Channel ranges	Re-enter the ranges

Channel ranges are not converted when the reference library or a measurement is converted. In AMICS 5, a range saved in AMICS 3.x points to roughly half the energy it used to, so spectra are quietly sorted into the wrong bins.

To fix a workflow:

Note the energies the old ranges covered. In AMICS 3.x, channel × 10 eV gives the energy (for example, channels 600–700 = 6.0–7.0 keV, around the Fe Kα peak)

Open the workflow's Spectrum Tree in AMICS 5

For each Ratio, Count or Total Count Clustering step, set the ranges again so they cover the same peaks, checking against the spectrum display

Classify a known sample and confirm the bins look as expected

Reference Spectra Compatibility

Using 4096-Channel References with Legacy Data

If you have legacy 2000-channel measurements and new 4096-channel reference spectra:

Convert the measurements to 4096 channels using the batch conversion tool

Reclassify using the 4096-channel reference library

Workflow Merge and Interpolation

When merging workflows that contain spectra of different channel counts:

AMICS automatically interpolates spectra during workflow merge

Reference spectra collected at 2000 channels are upsampled to 4096 during merge

This ensures consistent channel counts across all reference spectra in a workflow

Impact on Matching

4096-channel spectra provide:

Better peak separation — closely spaced energy lines are more clearly resolved

Improved accuracy for elements with overlapping K/L/M lines

Consistent dispersion — 4096 channels provide uniform energy-per-channel across the full spectral range

For most materials, the difference between 2000 and 4096-channel matching is small. The improvement is most noticeable for:

Complex multi-element materials

Elements with closely spaced energy lines (e.g., Ba-L and Ti-K)

Quantitative analysis where peak deconvolution accuracy matters

File Format

The channel count is stored per-measurement in the MRE database:

SpectraNumChannels in the Settings table records the channel count

XRay file headers include the channel count in the first reserved value

Dispersion and origin values are stored per-measurement and per-reference for accurate energy calibration