Changeset 680 in ETALON

Timestamp:

May 9, 2017, 6:12:52 PM (7 years ago)

Author:

delerue

Message:

Half-bare electron paper updated

Location:

papers/2017_IPAC/half-bare

Files:

• MOPAB024.pdf (modified) (previous)
• MOPAB024.tex (modified) (3 diffs)

papers/2017_IPAC/half-bare/MOPAB024.tex

@@ -83 +83 @@
 \section{Introduction}
 
-In normal conditions electrons are surrounded by a Coulomb field. When a relativistic electron interacts with matter or external fields it can loose part of its electric field and become ``half-bare''. In such state the  characteristics of its electromagnetic field are significantly modified and this can be observed when it interacts again with matter: the properties of the emitted radiation will be different. For example, in the case of relativistic electron multiple scattering in amorphous medium such modification results in the Landau-Pomeranchuk-Migdal and Ternovsky-Shul’ga-Fomin effects (see \cite{akhiezer,klein,thomsen}) of the electron bremsstrahlung suppression. 
+In normal conditions electrons are surrounded by a Coulomb field. When a relativistic electron interacts with matter or external fields it can lose part of its electric field and become ``half-bare''. In such state the  characteristics of its electromagnetic field are significantly modified and this can be observed when the particle interacts  with matter again: the properties of the emitted radiation will be different. For example, in the case of relativistic electron multiple scattering in amorphous medium such modification results in the Landau-Pomeranchuk-Migdal and Ternovsky-Shul’ga-Fomin effects (see \cite{akhiezer,klein,thomsen}) of the electron bremsstrahlung suppression. 
 
 Presently we propose to study the influence of the half-bare state of electron upon its transition radiation (TR). For the case when the electron becomes half-bare in the result of scattering or deflection in magnetic field the existence of such influence was theoretically predicted in \cite{trofymenko2011}. In \cite{nuovocim} it was shown that the electron also appears in the analogous state after crossing a conducting screen such as an optical transition radiation (OTR) screen. Such way of obtaining relativistic electrons in half-bare state provides certain advantages, from the experimental point of view, comparing to the case of electron deflection (e.g. unnecessity of the use of bending magnets). Therefore it is such approach that we adopt in the present paper and discuss the TR produced by electron impinging upon a downstream screen after having traversed an upstream one. 
@@ -89 +89 @@
 Let us note that previously the experimental investigation of TR produced by electron beam crossing a system of two screens was reported in \cite{shibata}. This experiment was made at three times higher energy (\SI{150}{MeV}) than the one provided at CLIO~\cite{Ageron:1989eq,bourdon:in2p3-00020744,Glotin:1992aj}. Here the increase of the TR signal at certain wavelengths with the increase of the distance between the screens was observed. In the present paper we show that the conditions available at the CLIO facility provide the possibility of investigating new features of half-bare electron TR, comparing to ones studied in \cite{shibata}. The proposed investigation also aims at answering certain questions which the study \cite{shibata} remained obscure. Particularly, it concerns the measurement of the ratio of TR signal from half-bare particle to the one from the particle having Coulomb field.   
 
-Let us also note that the example of direct experimental observation of gradual recovery of the Coulomb field of half-bare electron is presented in \cite{naumenko}. 
+Let us also note that the example of direct experimental observation of gradual recovery of the Coulomb field of the electron after its traversal of the conducting screen (based on the measurement of the electric field spatial distribution) electron is presented in \cite{naumenko}. 
 
 
@@ -182 +182 @@
 Summarizing the discussion presented above, let us outline the main new features of the present experimental proposal and the half-bare electron TR properties which it deals with. Firstly, we propose to make the comparison of TR signals from half-bare electron and the one from the particle with Coulomb field. It could allow to judge of the magnitude of the influence of the half-bare state of electron upon its TR and was not made in \cite{shibata}. Secondly, calculations show that at parameters available at CLIO facility it is possible to observe the effect opposite to the one, reported in \cite{shibata}, which is the decrease of the TR signal with the increase of the distance between the screens. Thirdly, we propose to study the evolution of the integrated signal (with respect to wide waveband) with the change of $L$, which provides more complete information (comparing to narrow waveband study) about the process of the electron field regeneration after crossing the screen. Finally, under the discussed conditions the study of the prewave zone effect in half-bare electron TR could be performed as well by varying the detector aperture and its distance from the screen.   
 
-The proposed investigation is of interest to better understand TR-based diagnostics where there is an ongoing controversy on the prediction of interferences between TR screens that are not always observed as predicted. It is also relevant for the TR-based diagnostics of extracted beams (with the use of bent crystal or magnetic field) which under certain conditions present the example of half-bare particle beams.
+The proposed investigation is expected to reveal valuable for TR-based diagnostics information about TR properties in the case when interference effects in radiation are significant. It is also relevant for the TR-based diagnostics of extracted beams (with the use of bent crystal or magnetic field) which under certain conditions present the example of half-bare particle beams.
 
 %\subsection{References}