Help

Usage

In principle, most of the inputs and outputs should be self-explanatory. Some hopefully helpful remarks are given below for your guidance.

Prerequisites

Please enable Javascript and cookies in your web browser, they are strictly required by beamcalc. Concerning Javascript, I test the codes only on Firefox and (mobile) Safari browsers. I don't have the resources to debug the code on anything else, in particular for variations between each Javascript implementation. Cookies are used by beamcalc to pass on user input from one tab to the other.
Please note, that some browsers in some configurations use either commas or dots as decimal separators. Try using the respective other, if your calculations fail unexpectedly.

Ion tab

M
Ion mass in atomic mass units (amu). The loupe button (🔎) directs you to a ion picker dialogue using either from tabulated values (AMDC AME 2020) for the stable and most abundant isotopes, or using Weizsäckers mass formula for unknown and exotic Z/N combinations.
Ecool energy
The equivalent energy of electrons at cooling condition, i.e. <vi> = <ve>. Clicking on the link solves the electron-tab including spacecharge corrections for electron cooling at the present ion energy.
ƒion
Revolution frequency of ions circulating in the ring on nominal orbit.
αp
Momentum-compaction factor.
η
Dispersion of the revolution frequency.
max. particles
Maximum number of particles at the space charge limit for coasting and cooled beam at the presently set machine parameters and also estimated for a bunched and uncooled beam at injection energy. See also chapter 7.2 of the LSR-TDR, their approach is followed by beamcalc.
ΔQsc
Tuneshift due to space charge, per μA and assuming cooled beam with emittance of 1 π·mm·mrad.

Electron tab

pin / unpin
Electron energy, acceleration voltage, expansion and electron current are coupled parameters. You have the choice of keeping either the final electron energy or the acceleration voltage pinned to a specific value and letting beamcalc adjust the other automatically, as you play with all of the beam parameters.
Ion energy
The ion energy at cooling condition, i.e. <vi> = <ve>.
Clicking on the link matches the ion-tab to the present electron energy.

Lifetime tab

Please set up the ion- and electron-tabs for your specific ion beam or the calculations in the lifetime-tab may be meaningless.

Several simplifications are applied to the code to keep the calculations tractable and responsive. They are meant as rule-of-thumb guide, not as definitive answer to all pressing problems of humanity. If you need exact results, please consult your friendly theoretician. Most of all, for now all calculations are performed assuming beams of atomic ions, i.e. any kind of nuclear or molecular physics are ignored from estimations of cross sections and lifetimes.

τcx
1/e-Lifetime of ion beam through charge exchange (Schlachter et al., 1983).
τstr
... through stripping on residual gas (Shevelko et al., 2009).
τscat
... through Rutherford scattering.
τrr
... through radiative recombination at cooling conditions. Calculated from Bethe-Salpeter formula.

Bethe-Bloch

Plot the particle energy and energy loss of a particle in matter using the Bethe-Bloch formula. Please note that Bethe-Bloch is only a simple estimate for orders of magnitude. More exact results can be derived with ATIMA, SRIM, GEANT4, or other simulation tools.

Doppler shift tab

Calculate the frequency shift when observing radiation from a moving emitter particle at 0°, 180° and a user-defined laboratory angle.