# VEX/ELS bible¶

The ELS Bible is for the instrument description prepared for data analysis.

VEX/ELS bible is provided from MSSL, and you can download from `../../../doc/VenusExpressELSDataAnalysisSummary2.pdf`

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Todo

To make the link active.

Package `irfpy.vels.bible`

contains the implementation.

## Error in ELS bible¶

### PSD calculation¶

PSD calculation in equation 10 contains a small error.
According to the definition in the bible, earray is in `eV`

and E is `J/eV`

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Thus, \(earray \times E\) should be in `J`

= `kg m2 / s2`

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To use the unit of `cm`

, the term should be changed to be
\((1e2)^2 \times earray \times E\).
So the correct expressions is \(PSD [cm^{-6} s^3] = \frac{raw \times m_e^2}
{GF \times accutime \times 2 \times (1e4 \times earray \times E)^2 \times A_A}\)

The error has been corrected for the implementation of `irfpy.vels.bible.flux.raw2psd()`

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