\section{Trade-off report}
\label{sec:trade-off-report}

\subsection{Cherenkov detector}
The simulation detailed in section \ref{sec:performance-analysis} has been performed individually with and without a Cherenkov detector in order to investigate whether or not the AHEPaM requirements can be full-filled with both setups. The requirement regarding the electron uncertainties has proven to be the most difficult one to achieve due to the contribution of protons to the electron channels. This contamination is significant due to the higher proton flux compared to the electrons expected for the \ac{GCR} (see fig. \ref{fig:adriani-e-p}).\newline
While the methods introduced in \ref{sec:performance-analysis} utilizing thresholds in the different detectors of the instrument have reduced the contamination already significantly even without a Cherenkov detector, this improvement has proven to be insufficient in order to full-fill the given requirements. Introducing the Cherenkov to the setup allowed for a further suppression of the proton contamination and hence significant lower electron uncertainties. Additionally, the Cherenkov allows to separate protons above and below 2~GeV allowing for better energy resolutions up to 2~GeV as well as providing an integral channel for protons above 2~GeV. Hence, from a measurement technique perspective the Cherenkov detector is highly preferred.\newline 
From a technical point of view, the Cherenkov detector increases the complexity of the instrument. Especially the high voltage that is necessary in order operate the \ac{PMT} of the Cherenkov detector has to be considered. Furthermore, the Cherenkov detector has to be connected to its \acs{PMT} and the rest of the instrument mechanically and thermally. The technical detailed are further described in section \ref{sec:technology-assessment}. It is important to note that Cherenkov detectors have been already used successfully for space mission in the past (including instruments build in Kiel \cite{ahepam-heritage}). \newline
Based on the analysis above we have decided that a Cherenkov is recommended in order to full-fill the measurement requirements and that the additional technical efforts are both manageable and appropriate for the benefits. However, a de-scoped version of \ac{AHEPaM} without the Cherenkov detectors has been proven to provide the capabilities of separating electrons from protons utilizing the methods described in \cite{ahepam-djf} based on sufficient statistics which could be achieved by integrating over longer time periods. Given the small temporal variations of electrons in the energy range above 50~MeV this de-scoped version is expected to provide electron fluxes within the required systematical and statistical uncertainty range if the requirements on the integration period for electrons would be relaxed.

\subsection{Trade-off for front-end electronics}

We do not expect that AHEPaM will measure high count rates, in fact we are challenged to satisfy the statistical requirements (see AHEPaM measurement requirements R-AHEPaM-023, 027, and 031). Thus the AHEPaM front-end electronics (FEE) do not need to be very fast, but we would very much like to have accurate measurements of the deposited energy.

The FEE that we designed for the DORN instrument aboard the Chinese Chang'E-6 lunar lander mission fulfills exactly these requirements. It is intended to measure very rare alpha-decays of radon on the lunar surface. That design derives heritage from balloon experiments as well as our instruments on Solar Orbiter, but with lower count rates.

More information about the design can be found in \url{https://cloud.rz.uni-kiel.de/index.php/s/YAWWZRRYrrS7Kg3}

\begin{figure}[h]
	\centering
	\includegraphics[width=0.5\linewidth]{cau-ath-djf-0007_i1-0/media/dorn-shaper-first-page-snippet.pdf}
	\caption[]{DORN Signal Processing paper}
	\label{fig:micd}
\end{figure}
