Usage
In principle, most of the inputs and outputs should be self-explanatory. Some hopefully helpful remarks are given below for your guidance. Generally, it is assumed that you start your workflowby defining the ion beam, then the electrons, than to the lifetime tab. Results from previous tabs are propagated where it is useful.
Jump to: Ion · Electron · Lifetime · Bethe-Bloch · Doppler · Meastime
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
- Z
- Nuclear charge of the given ion
- 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.
- q
- Atomic charge state of the given ion
- E
- The ion beam energy can be entered in various forms/units: MeV/u, MeV, kV (eq. ion source potential), kHz (ion beam revolution frequency), or γ (relativistic factor).
- Ring
- Please select either CRYRING@ESR, ESR, HESR. Please note that this might have side effects, as my priority is presently on CRYRING@ESR. Please let me know if you are aware of any mistakes. Please let me know if you would like other machines included in this list.
- Injector
- Only for CRYRING@ESR: Local RFQ, local source, ESR. Emittances are scaled according to the start conditions for beam of each injector. Also applies different sanity checks.
- 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 and does not work very well at the low energy limit.
It might still be usefull as an order-of-magnitude estimator for certain scenarios, though, YMMV.
More exact results can be derived with ATIMA,
SRIM, GEANT4, or other simulation tools.
Doppler shift
Calculate the frequency shift when observing radiation from a moving emitter particle at 0°, 180° and a user-defined laboratory angle.
Meastime
The counting efficiency depends on ion beam lifetime and duty cycle. This helper tool estimates the ideal timing to optimize the counting statistics at given beam conditions. The output from the Meastime Optimizer implies, that it is only the experiment which is defining the cycle time; i.e. there are no dependencies on external timers, such as upstream injector machine cycles. Nevertheless, there could be very good reasons to measure faster or slower than recommended by this tool.