Changeset 741 in ETALON for papers/2016_HDR_ND/Advanced_diags/emittance.tex

Timestamp:

Sep 25, 2017, 10:58:10 PM (7 years ago)

Author:

delerue

Message:

More work on HDR

File:

• papers/2016_HDR_ND/Advanced_diags/emittance.tex (modified) (3 diffs)

papers/2016_HDR_ND/Advanced_diags/emittance.tex

@@ -686 +686 @@
 \end{figure} 
 
-The most important check to validate our method was to demonstrate that the beam size on the final screen was not affected by the insertion of other screens. This was done by measuring the beam size on the fourth screen (OTR4) with different configurations of the other three screens as shown on figure~\ref{fig:motr_screens}. As can be seen on that image no change in beam size was seen in $x$ and a 5\% change was seen in $y$. Using the beam size measured on each of the four screen it was then possible to measure the emittance. The beamline where the screens were installed had a non zero dispersion and this effect had to be taken into account as described in ~\cite{1748-0221-6-07-P07004}. Using this method we found a transverse emittance $\epsilon_x = \SI{160.1 }{nm.mrad} \pm \SI{11.5 }{nm.mrad}$ in very good agreement with the emittance measured by a quadrupole scan performed immediately after and that gave an emittance of  $\epsilon_x = \SI{162}{nm.mrad}$.
+The most important check to validate our method was to demonstrate that the beam size on the final screen was not affected by the insertion of other screens. This was done by measuring the beam size on the fourth screen (OTR4) with different configurations of the other three screens as shown on figure~\ref{fig:motr_screens}. As can be seen on that image no change in beam size was seen in $x$ and a 5\% change was seen in $y$. Using the beam size measured on each of the four screen it was then possible to measure the emittance. The beamline where the screens were installed had a non zero dispersion and this effect had to be taken into account as described in~\cite{1748-0221-6-07-P07004}. Using this method we found a transverse emittance $\epsilon_x = \SI{160.1 }{nm.mrad} \pm \SI{11.5 }{nm.mrad}$ in very good agreement with the emittance measured by a quadrupole scan performed immediately after and that gave an emittance of  $\epsilon_x = \SI{162}{nm.mrad}$.
 
 
@@ -705 +705 @@
 
 \subsubsection{Criticism: OTR interferences}
+\label{sec:OTR_interference}
 
 When we first proposed this experiment some colleagues warned us that according to~\cite{Verzilov2000135} we would face difficulties due to interferences between the screens as they were located in the pre-wave zone of each other. 
@@ -712 +713 @@
 As can be seen on figure~\ref{fig:motr_images} we did not see this effect. Further worked on these interferences has been presented in 2015 and confirmed that our setup was not subject to such interferences~\cite{RREPS-15-Bergamaschi} as our images were integrated over a large number of wavelengths.
 
+To put a final conclusion on this matter I also proposed, together with a colleague, another OTR interference experiment~\cite{Trofymenko:2017ils} that should be conducted in a few months at CLIO and that will study the conditions under which we conditions the pre-wave effect is visible.
 
 \section{Other techniques: Emulsion based measurement and masked OTR}