Release Notes | GRASP-X

Version 2.49.0 August 2026

The calculator now lives at /calculator, and older links to it still work. The workbook covering a whole calculation is offered from the completion dialogue, above the per-composition downloads.

Version 2.48.0 August 2026

The whole of a calculation can again be taken as one Excel workbook, with an overview sheet and a sheet for each composition and database.

Version 2.47.0 August 2026

Figures can be saved as PDF and EPS again, and the whole of a run can be taken as a single workbook with one sheet per table.

Version 2.46.0 August 2026

While a calculation runs the page now shows only that it is working, and the results appear together when every composition is ready.

Version 2.45.4 August 2026

Interface improvements.

Version 2.45.3 August 2026

The zoom inset now opens on the first press.

Version 2.45.2 August 2026

Interface improvements.

Version 2.45.1 August 2026

Version 2.45.0 August 2026

While a calculation runs, the results area now shows that work is in progress rather than staying empty, and the customized-graph section appears once there are results to graph.

Version 2.44.1 August 2026

The site records the network a visitor came from rather than the address itself, which is what a map is drawn from.

Version 2.44.0 August 2026

The site now keeps its own record of the pages requested and of any request it could not answer.

Version 2.43.0 August 2026

A page that cannot be found, or a request the server could not answer, is now shown on a page of the site rather than a bare server message.

Version 2.42.3 August 2026

The absorption-edge treatment has been compared against Monte Carlo on eleven materials, two of them ceramics in which the element carrying the edge is a minor constituent rather than the bulk of the material.

Version 2.42.2 August 2026

Interface improvements.

Version 2.42.1 August 2026

Interface improvements.

Version 2.42.0 August 2026

The published site failed to start after the previous release and is running again.

Version 2.41.9 August 2026

Curve colours in the customized graph are chosen from the palette, as markers are. The panel that accepted any colour has been withdrawn.
Interface corrections in the zoom inset control.

Version 2.41.8 August 2026

The customized graph no longer becomes slow to use once zoom insets have been added.
A downloaded buildup factor table is named for the penetration depth it holds.
Clicking a control no longer selects the text on it.
Interface corrections in the chart legends and the release notes.

Version 2.41.7 August 2026

Interface corrections.

Version 2.41.6 August 2026

Interface corrections.

Version 2.41.5 August 2026

Interface corrections in the download controls.

Version 2.41.4 August 2026

The guided walkthrough opens any section that has been folded away before describing it.
Interface corrections in the results toolbar and the download controls.

Version 2.41.3 August 2026

In the buildup factor section the table downloads follow the charts and the branch selector, and the selector is labelled.
The dialogue gathering the tables of a run can be reopened from the results toolbar.

Version 2.41.2 August 2026

The absorption-edge treatment has been compared against Monte Carlo on nine materials over the full range of energies and penetration depths. The element carrying the absorption-edge window differs between them, so the treatment is no longer verified on a single edge.

Version 2.41.1 August 2026

The absorption-edge treatment has been compared against Monte Carlo on a further material over the full grid of energies and penetration depths.
Interface corrections in the dialogue shown on completion of a calculation and in the guided walkthrough.

Version 2.41.0 August 2026

Every message the program displays is drawn from a single catalogue, so the same situation is described in the same terms wherever it appears.
The release notes have been rewritten throughout, and the declared classification of each release reviewed and corrected where it was wrong.
The note shown at an uncertain equivalent atomic number no longer implies that the value has been verified.

Version 2.40.1 August 2026

Energies at which the equivalent atomic number cannot be selected uniquely are marked individually rather than by a broad shaded band.
The accompanying note states that the selection at such a point is uncertain, rather than that the value is unreliable.
The reduction in downloaded code described in the previous release is now in effect.

Version 2.40.0 August 2026

A malformed or oversized request is refused with an explanation instead of failing.
Pages load a smaller amount of code, and dragging the penetration-depth slider is smoother.

Version 2.39.2 August 2026

The absorption-edge treatment has been checked against Monte Carlo on a further material, chosen so that the element carrying the edge is not the one every earlier test material had in common. Until now the rule had been verified on effectively a single absorption edge.

Version 2.39.1 August 2026

These release notes now cover the whole history rather than the most recent releases only.

Version 2.39.0 August 2026

These release notes are now written for the reader rather than the maintainer.
The documentation page has been revised to describe the current treatment of absorption edges.
Interface improvements in the buildup section, where changing the database no longer redraws everything in one frame.

Version 2.38.0 Methodology August 2026

Where a material contains more than one heavy element, the buildup factor is now reported correctly just above each of their absorption edges, and not only above that of the heaviest. The edge lying just below the source energy decides which element holds the window.

Version 2.37.0 Methodology August 2026

The buildup factor section reports a single recommended result for each database, rather than several alternatives side by side.
A density of zero or below is refused with a message. It used to be accepted: the attenuation tables came back correct, since they do not depend on density, and only the half-value layer, the tenth-value layer and the mean free path came back empty, with nothing saying why.

Version 2.36.5 Methodology August 2026

The absorption-edge treatment is now available on the XCOM-ANSI database as well.
On that route the substitute is chosen among the elements the standard tabulates, no other having coefficients to read. Where the tables carry no row at that energy the value is left as it was rather than invented.

Version 2.36.4 August 2026

The guided walkthrough covers the customized graph in seven steps rather than three, and the folded band of animations beneath that section has been removed.

Version 2.36.3 Methodology August 2026

The recommended buildup factor now includes the absorption-edge treatment, so a single result is reported rather than two.
The correction applies to the buildup above one rather than to the buildup factor itself. A buildup factor cannot fall below one, and at shallow depth just above an edge the previous form produced values that did.
The guided walkthrough continues into the results once a calculation has been run, and covers the customized graph.

Version 2.36.2 August 2026

The wording of the guided walkthrough has been revised throughout, to name the quantity or control rather than describe it conversationally.

Version 2.36.1 August 2026

The guided walkthrough continues into the results, introducing each section in turn from the composition heading through to the downloads, and opening the sections that arrive folded.

Version 2.36.0 Methodology August 2026

Just above the absorption edge of a heavy constituent the buildup factor rises by several orders of magnitude. This region is now reported, where previously it was understated, at both K and L edges.
Values obtained by extrapolation rather than by solution are marked wherever they are shown.
Interface corrections in the guided walkthrough.
A corrected page reaches the browser without the reader having to clear anything.

Version 2.35.1 Methodology August 2026

A pronounced peak just above a heavy element's absorption edge is reported rather than omitted, and is marked where it is. Taking the equation's own solution there removed the peak entirely; carrying the branch across understates it but keeps it on the chart.

Version 2.35.0 Methodology August 2026

The table of equivalent atomic numbers again lists every solution found at each energy. A filter meant for the reported branch had been removing solutions from the table as well.
The reported branch no longer discards a valid solution. Whether a value solves the equation and which two elements its buildup factor should be read between are separate questions, and the second was being asked of the first.

Version 2.34.2 August 2026

Interface improvements in the guided walkthrough: it is positioned before it is shown, its example is typed more slowly, and it shows that several materials may be carried through one run.

Version 2.34.1 August 2026

The guided walkthrough opens when it is selected. It never did, whatever the setting said.

Version 2.34.0 August 2026

A guided walkthrough of the page is offered from the help control, filling in a worked example as it goes.

Version 2.33.1 August 2026

Interface improvements in the input messages and the section headings.

Version 2.33.0 August 2026

The results layout that keeps a composition's heading and its database control under the navigation is now on for everyone.
A mistake in an input is shown at the input, with the reason beside it, rather than in a dialogue that says something is wrong without saying which field.

Version 2.32.10 August 2026

Everything the tool has to say outside a form now arrives in one message box, in the site's own type, rather than in the browser's plain alert.
Opening a table on its own page failed for every table in the previous release, and works again.

Version 2.32.9 August 2026

The database can be changed on the full-table page, and the table is redrawn in place, so a comparison no longer means returning to the results.
An experimental results layout, off by default, keeps a composition's heading and its database control under the navigation for as long as that composition is on screen.

Version 2.32.8 Methodology July 2026

An element lying directly on its own absorption edge is no longer used as a reference for the material's regime, where the material itself is not at that edge. Its tabulated buildup factor there can stand orders of magnitude above the value a little further up, however small its share of the interpolation.
Where no suitable pair of elements surrounds the equivalent atomic number the value is taken from the nearest suitable element rather than extrapolated beyond them, and the row is marked. Extrapolating between values that differ by orders of magnitude could return a buildup factor below one, which cannot occur.

Version 2.32.7 Methodology July 2026

Buildup factors are no longer read across an absorption edge on any reported material. A heavy element becomes far more transparent to its own fluorescence just above its edge, and a value interpolated across that step belongs to neither of the elements it was read between.
A material with no heavy element near an edge returns exactly what it returned before.

Version 2.32.6 Methodology July 2026

The absorption-edge treatment now considers how far above an edge a tabulated value lies, and not only which side of it. Just above an edge a material is unusually transparent to its own fluorescence, and a value read between two elements at different distances from their edges belongs to neither.

Version 2.32.5 Methodology July 2026

The absorption-edge treatment covers the whole route to a buildup factor, including the equivalent atomic number itself, rather than only the final interpolation.

Version 2.32.4 Methodology July 2026

The absorption-edge check treats every shell alike rather than the innermost one only. An outer edge interrupts the cross section in the same way and produced the same false peaks.

Version 2.32.3 Methodology July 2026

A check for buildup factors read across an absorption edge is being tried on the development build. Where the two tabulated elements bracketing an equivalent atomic number lie on opposite sides of their own edges, the value read between them is not physical.
Interface improvements in the download controls beneath the buildup section.

Version 2.32.2 July 2026

The reported branch is labelled Recommended, without a version number.
Interface improvements on the documentation page.

Version 2.32.1 July 2026

Interface improvements throughout: a format menu is drawn by the site so that it matches on every browser, the surface chart lists its surfaces beside it, and every page is titled by what it is.
The fast neutron removal cross section is no longer offered in the customized graph, being one number for a composition rather than a curve against energy.

Version 2.32.0 Methodology July 2026

A single recommended buildup factor is reported for each material, obtained by following one continuous equivalent atomic number across the energy range.
The interaction-weighted method is withdrawn, and the selection rule that was built on it goes with it.
Figures are saved as image files written by the browser. The server no longer draws them, so PDF and EPS are not offered.
Each table is downloaded from its own section; the single workbook covering a whole run is withdrawn.

Version 2.29.1 July 2026

Interface improvements in the customized graph parameter cards.

Version 2.29.0 July 2026

These release notes are generated from a version record kept with the code, and each release declares whether it may have moved a computed number.
Interface improvements in the heading of the buildup factor section.

Version 2.28.0 July 2026

Each chart carries its table downloads in a section beneath it.
Interface improvements in the customized graph: parameter cards can be folded away, and the panel fits a laptop screen.

Version 2.27.1 July 2026

Interface improvements in the customized graph parameter cards.

Version 2.27.0 July 2026

Quantities for a custom figure are chosen from a menu, which leaves more room for the figure, and the axis titles are filled in from what is plotted.
The fast neutron removal cross section can be plotted.

Version 2.26.0 July 2026

Interface improvements in the results: buildup factors are named in full, the buildup chart opens on the recommended branch, and the mathematics in the documentation contents renders correctly.

Version 2.25.1 July 2026

Interface improvements in the results and the dialogues.

Version 2.25.0 July 2026

The interaction processes are available as a table, downloadable like the others.
Interface improvements in the results, which are laid out more compactly with each table reached from the chart it belongs to.

Version 2.24.1 July 2026

Interface improvements in the dialogues and the customized graph.

Version 2.24.0 July 2026

A dialogue on completing a calculation offers the tables for download, and can be switched off.
Interface improvements in the customized graph: the deviation curves carry legends, named automatically and editable, set in mathematical notation.

Version 2.23.0 Methodology July 2026

A single recommended buildup factor is reported for every material, with a note describing how it is obtained.

Version 2.22.3 Methodology July 2026

Where a material contains several heavy elements, the reported branch changes over at the highest absorption edge rather than the lowest. The lowest usually belongs to a minor constituent and carries the crossover far below the energies the material's own absorption governs.

Version 2.22.2 Methodology July 2026

The energy at which the reported branch changes over near an absorption edge can be adjusted.

Version 2.22.1 Methodology July 2026

Below the absorption edge the third selection rule follows the continuous branch rather than the window-matching one, so that the two agree away from the edge.

Version 2.22.0 Methodology July 2026

Two further rules for selecting the equivalent atomic number near an absorption edge are offered for comparison with the existing one.
Absorption edge energies are available for every element in the cross-section tables.
Two plotted curves can be compared against each other in a deviation panel under the figure.

Version 2.21.2 July 2026

Interface improvements in the customized graph figure settings.

Version 2.21.1 July 2026

Interface improvements in the customized graph figure settings.

Version 2.21.0 July 2026

Point sizes for the title, the axis titles and the legend apply to the preview and to every export.
Interface improvements in the customized graph toolbox, whose figure settings are folded into a collapsible section.

Version 2.20.0 Methodology July 2026

An alternative calculation method is offered on the LSPBF database, in which each element keeps its own buildup contribution rather than the material being reduced to a single equivalent atomic number.
Measured data can be imported and plotted alongside the computed curves.
A penetration depth of zero no longer makes the calculation fail.

Version 2.19.1 July 2026

Interface improvements on the full-table page: a table wider than the page scrolls within its own box rather than moving the page sideways.

Version 2.19.0 July 2026

A result table can be opened on a page of its own, where it is shown in full.
A downloaded table records the database it was produced from.

Version 2.18.2 July 2026

Interface improvements in the navigation bar and the browser tab icon.

Version 2.18.1 July 2026

Interface improvements in the navigation bar.

Version 2.18.0 July 2026

Interface improvements in the footer.

Version 2.17.1 July 2026

Interface improvements in the customized graph toolbar.

Version 2.17.0 July 2026

The figure shape, square or wide, is chosen in the customized graph toolbar and governs the preview and all four export formats alike.

Version 2.16.1 July 2026

A legend in a PDF or EPS export is sized and placed to match the preview, and cannot run outside the figure frame however long its entries are.

Version 2.16.0 July 2026

Interface improvements in the tables and the walkthrough: a download starts on CSV, copying a table or a value says that it has been copied, and the walkthrough looks at the preview only once something is drawn in it.

Version 2.15.1 July 2026

A figure can be set square or wide, and the shape applies to the preview and to every export format.
Interface improvements throughout: a confirmation when something is copied, table downloads starting on CSV, and a new product mark in the navigation, the footer and the browser tab.

Version 2.15.0 July 2026

In the customized graph the legend can be moved and resized in the preview, with alignment guides while it is dragged, and its position and size are carried into the exports.

Version 2.14.1 July 2026

Interface improvements in the customized graph selection lists.

Version 2.14.0 July 2026

In the customized graph each selected value carries its own legend, colour and marker, and the readout under the pointer names the curve in readable form.

Version 2.13.3 July 2026

Interface improvements on small screens: a chart box sizes itself to its contents, the depth-slider labels thin to a readable subset, and the copy control follows the table rather than sitting over its first heading.
These release notes have been rewritten in a plainer form.

Version 2.13.2 July 2026

Interface improvements in the walkthrough.

Version 2.13.1 July 2026

Where a browser cannot draw a chart the program now says so, and says where the same values can still be read, instead of leaving an empty frame.
Support has been widened to older browsers.

Version 2.13.0 July 2026

The interface adapts to tablet and phone screens, with controls sized for touch input.

Version 2.12.1 July 2026

In the customized graph several equivalent atomic number roots can be selected at once, each drawn as its own curve.

Version 2.12.0 July 2026

A magnified inset is carried into the PDF and EPS exports.
Interface improvements in the customized graph.

Version 2.11.7 July 2026

Interface improvements in the customized graph: the form layout, the placement of the selection panels and the custom-colour panel.

Version 2.11.6 July 2026

In the customized graph the third axis of a surface chart takes a label of its own, and a label typed for an axis overrides the automatic one.

Version 2.11.5 July 2026

Opening the customized graph folds away the tables above it, which otherwise left the builder several screens below the fold.

Version 2.11.4 July 2026

In the customized graph each curve of a multiple selection takes its own colour, the palette is larger, and any colour may be entered directly.

Version 2.11.3 July 2026

In the customized graph a buildup factor is listed once, with a selector for the equivalent atomic number root, rather than once per root.

Version 2.11.2 July 2026

In the customized graph a quantity a surface chart cannot show is unticked and locked with an explanation for as long as the surface chart is on.

Version 2.11.1 July 2026

The interaction-process and shielding-parameter charts are framed on the data actually plotted rather than on the requested energy window, so a database covering a narrower range no longer leaves most of the figure empty.

Version 2.11.0 July 2026

In the customized graph both axes fit the data plotted unless a limit is given, a curve colour can be chosen freely, and an axis label applies to a surface chart as well as to a curve.
Interface improvements in the customized graph.

Version 2.10.7 July 2026

Interface improvements in the walkthrough.

Version 2.10.6 July 2026

Interface improvements in the walkthrough: each database keeps its own energy axis and its own columns, the surface is a rendering of the real one, and the framing stays on the control being described.

Version 2.10.5 July 2026

Interface improvements in the walkthrough: its charts are visible, having been drawn and then held transparent by a rule left from an earlier version.

Version 2.10.4 July 2026

Interface improvements in the walkthrough: the charts are drawn, the framing is closer, and a selection panel opens beside the control that opened it.

Version 2.10.3 July 2026

Interface improvements in the results heading and in the framing of the walkthrough.

Version 2.10.2 July 2026

Interface improvements in the walkthrough: the framing follows the control being described, and the charts are drawn at a size that can be read.
These release notes have been rewritten to summarise interface work rather than itemise it.

Version 2.10.1 July 2026

An exported figure now matches the one on screen in typeface, colour, marker and line style.
A malformed request for a figure is refused rather than answered in the wrong format.
Interface corrections in the walkthrough and the composition inputs.

Version 2.10.0 July 2026

The illustrated walkthrough has been rebuilt around a real calculation, so every curve and every control in it behaves as the program does.

Version 2.9.1 July 2026

Interface improvements in the results: compositions are grouped, and the buildup-factor legend takes the layout the other legends have.

Version 2.9.0 July 2026

Calculations return less data and complete faster, and the charts are drawn in order of relevance rather than all at once.
The documentation page has moved, with the earlier address redirected to it.

Version 2.8.2 July 2026

Interface improvements in the charts and the branch selector.

Version 2.8.1 July 2026

With penetration depth on the abscissa the equivalent atomic number root is chosen for each energy separately, and only the roots that exist at that energy are offered.
Interface improvements in the charts: a figure title is no longer clipped in the preview or dropped from an export, and the abscissa label follows the quantity plotted.

Version 2.8.0 July 2026

Buildup factors can be plotted against penetration depth as well as photon energy, and several depths or energies can be drawn at once, each as its own curve.
Figures can be exported as PDF and EPS, with the format chosen at download.
A single-element input no longer shows the recommended traces, which duplicate the only equivalent atomic number there is.

Version 2.7.3 July 2026

Interface improvements on the documentation page: the width of the article, the contents panel and the scrollbars.

Version 2.7.2 July 2026

In the customized graph each selected quantity carries its own controls, and the penetration depth is chosen per quantity, so several depths can be drawn in one figure.
Interface improvements on the documentation page.

Version 2.7.1 Methodology July 2026

An alternative rule for selecting among the equivalent atomic number solutions is offered, based on how readily the material transmits the energies just below the source energy.
In the customized graph a surface chart now follows the buildup variant chosen for it, as the corresponding curve already did.

Version 2.7.0 Methodology July 2026

The tabulated database is evaluated on its own energy grid, from 0.01 to 10 MeV, rather than on the energy list belonging to the fitted route. The fitted route is unchanged and still reaches 15 MeV.

Version 2.6.9 July 2026

A layout fault on the main page has been corrected.

Version 2.6.8 July 2026

The main page and the documentation have been revised, and the explanations and input labels reworded.

Version 2.6.7 July 2026

A documentation page setting out the physics and the working equations behind each computed quantity, with a contents panel generated from the text itself.

Version 2.6.6 July 2026

Interface improvements in the customized graph: the order and spacing of the notation hints, and the alignment of the logarithmic controls.

Version 2.6.5 July 2026

Only the 1991 edition of the fitted buildup-factor coefficients remains; the earlier edition and the control that selected it are withdrawn.

Version 2.6.4 July 2026

Interface improvements in the results and the customized graph: the continuous branch is named Recommended wherever it appears, the interaction processes carry shorter names, and an explanation is no longer clipped by the content around it.

Version 2.6.3 July 2026

Interface improvements throughout: an explanation on every control, exported tables that name the buildup variant they hold, and a workbook that covers every variant of a run.

Version 2.6.2 July 2026

Interface improvements in the customized graph and the charts: every buildup variant is offered for plotting, grouped by dosimetric type, and the axis frames are simplified.

Version 2.6.1 July 2026

Interface improvements throughout the results: an explanation is available on each control, buildup factors are named by their dosimetric type, and the continuous branch is called Recommended.

Version 2.6.0 July 2026

Buildup factors for effective dose and for photon flux are offered alongside those for exposure, and a finite-medium model alongside the infinite one.

Version 2.5.0 July 2026

A second edition of the fitted buildup-factor coefficients can be selected.
A whole run can be exported as a single workbook.

Version 2.4.0 Methodology July 2026

On the tabulated database the buildup factor is read with the absorption edges of the constituent elements taken into account.
Interface improvements in the charts: panning, zooming and a magnified inset, and mathematical notation in the axis labels of the customized graph.

Version 2.3.7 June 2026

Interface improvements in the customized graph and the help panel: a logarithmic ordinate, the continuous branch offered as a quantity to plot, and a walkthrough of the inputs and the figure builder.

Version 2.3.6 Methodology June 2026

The continuous branch is held within the range of atomic numbers the material actually contains, and energies where the choice cannot be made confidently are marked as such.
The branch is available on both databases.

Version 2.3.5 Methodology June 2026

Where several equivalent atomic numbers solve the equation at one energy, a single continuous branch is now followed across the energy axis and reported as one curve.

Version 2.3.0 June 2026

The reference data behind the tabulated database has been extended, and chemical formulas with fractional subscripts are accepted.

Version 2.2.5 Methodology May 2026

Where the ratio curve is not monotonic in atomic number the equation has more than one solution. Every solution is now found and reported, rather than the first one encountered.
On the tabulated database the ratio is formed against the total attenuation including coherent scattering, which is the definition that database was compiled under. Its equivalent atomic numbers and buildup factors change with it.

Version 2.2.0 Methodology May 2026

The tabulated buildup-factor database now derives its own attenuation coefficients and its own equivalent atomic number rather than reusing those of the fitted route. The two routes are independent from this release, and their results differ where the definitions behind them differ.
The database is chosen for each composition separately.

Version 2.1.0 Methodology May 2026

A second buildup-factor database is available, tabulated for each element rather than fitted, and can be selected alongside the existing one.
The charts are interactive and can be panned and zoomed.

Version 2.0.0 May 2026

The interface has been rebuilt throughout, and figures can be exported as images.
The second cross-section source has been withdrawn.

Version 1.3.2 Methodology May 2026

The ratio used to solve for the equivalent atomic number now excludes coherent scattering from its denominator, following the definition under which the buildup-factor coefficients were fitted. Reported equivalent atomic numbers and buildup factors change with it.

Version 1.3.1 Methodology May 2026

Buildup factors are computed over a grid of penetration depths chosen by the reader, and any result table can be downloaded.
The range of atomic numbers searched when solving for the equivalent atomic number now covers the whole tabulated range, so solutions outside the earlier window are found.

Version 1.3.0 Methodology May 2026

The equivalent atomic number is reported, together with the fast neutron removal cross section. The incoherent cross section is now read from the tables alongside the total, which the earlier releases did not use.
This release notes page.

Version 1.2.0 April 2026

A composition whose fractions do not sum correctly is refused with an error rather than answered with an empty result.

Version 1.1.0 Methodology April 2026

A second cross-section source can be selected, and the mass attenuation coefficient is broken down by interaction process and by constituent element.
The order in which the effective atomic number is formed from the cross sections has been corrected, so that quantity changes.

Version 1.0.0 February 2026

First release. A composition is entered as a chemical formula, and the mass attenuation coefficient, the half and tenth value layers, the mean free path, the effective atomic number and the effective electron density are reported from the XCOM cross sections.

GRASP-X Release Notes