\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
-%% GSI Scientific Report 2013
+%% GSI Scientific Report 2013
%% \setlength{\titleblockheight}{27mm} KG
\setlength{\titleblockheight}{35mm}
\begin{document}
- \title{Assessing the vacuum compatibility of the CBM micro vertex detector\thanks{Work supported by BMBF (05P12RFFC7), HIC for FAIR and GSI}}
+ \title{Assessing the vacuum compatibility of the CBM Micro Vertex Detector\thanks{Work supported by BMBF (05P12RFFC7), HIC for FAIR and GSI}}
\author[]{G. Kretzschmar}
\author[]{M. Koziel}
\maketitle
-The CBM micro vertex detector (MVD) will operate in a moderate vacuum of about $10^{-4}$ $mbar$ to minimize multiple scattering. The vacuum compatibility of the detector needs to be validated with respect to thermal management of the MVD-stations and their mechanical integrity during the design and prototyping phase. A dedicated vacuum vessel, located at the IKF Frankfurt, allows for systematic studies w.r.t. selection of material, detector operation and cooling in vacuum.
+The CBM Micro Vertex Detector (MVD) will operate in a moderate vacuum of about $10^{-4}$~mbar to minimize multiple scattering. The vacuum compatibility of the detector needs to be validated with respect to thermal management of the MVD stations and their mechanical integrity during the design and prototyping phase. A dedicated large-volume vacuum vessel, located at the IKF Frankfurt, allows for systematic studies on the selection of material, the detector operation and thermal management in vacuum.
-The setup comprises a 260 liter stainless steel vacuum chamber with multiple flanges providing a flexible access setup inside. Full-size MVD modules can be housed and operated, see Fi. \ref{fig:vacuum} right picture. The chamber is supplied with a combination of rotary and turbomolecular pumps to routinely reach pressures of $2 \cdot 10^{-6}$ $mbar$, despite of the chamber volume and the variety of feedthroughs for signals and cooling media. The pressure is measured with penning-pirani sensor systems. Special emphasis is put on operating the detector at temperatures below room temperature and hence, providing active cooling inside the vessel is mandatory.
-
-To characterize cooling media and to select a reliable concept of piping inside the vacuum, a dedicated setupwas constructed, based on copper pipes and Swagelok fittings. The circuit inside the vacuum chamber was connected to a commercial cooling system (HUBER). With standard Si-oil cooling liquid circulated at atmospheric pressure no leak was observed. However at pressure of $10^{-2}$ $mbar$ and 1 week of pumping signs of the coolant were spotted on the Swagelok connectors placed inside the vacuum. After excluding all mechanics-related reasons for observed leaks, the cooling liquid was changed to glycol. After this change no leaks were observed, also when replacing the copper pipes with polyurethane pipes. These studies underline the need of a careful preparation of reliable pipe interconnections and do suggest not to employ
-coolants which feature strong creeping, like Si-oil.
-
-Outgassing of materials has to be kept at a minimum, both to not spoil the vacuum close to the target and to avoid contamination of surfaces. The setup allows to characterize outgassing of detector components, like (flex) cables, adhesives or electronic components. Outgassing rates of MVD components will be evaluated with the so-called throughput method or the gas accumulation method \cite{Redhead}. However, outgassing measurements with higher accuracy request a large probe area compared to the setup area.
-
-The vacuum setup allows for evaluation of thermal management of the MVD components, i.e.~heat-sinks and sensor carriers based on high-performance materials like chemical vapor deposition (CVD) diamond and thermal pyrolitic graphite\footnote{Materials selected due to their outstanding heat conductivity, allowing at the same time a minimum material budget, which represent another important constrain for the MVD.} (TPG). The evaluation is carried out by contact temperature sensors (DS1820) in combination with a high-resolution infrared camera positioned outside of the chamber (through a dedicated zincselenide window transparent for infrared). The contact sensors serve as a reference for the infrared-based characterization of the detector setup, and they allow at the same time for a proper calibration of IR camera with respect to the reflectivity of materials and reference measurements. To emulate the expected MVD-sensor heat dissipation, Kapton flexible heaters from OMEGA \cite{OMEGA} are glued on materials under
-evaluation, see figure \ref{fig:vacuum}.
-
-It is planned to characterize in vacuum full-size detector prototypes like PRESTO (PREcursor of the Second sTatiOn), see \cite{PRESTO}, with a focus on the long-term operation in vacuum.
+The setup comprises a 260 liter stainless steel vacuum chamber with multiple flanges providing a flexible access setup inside. Full-size MVD modules can be housed and operated, see Fig.~\ref{fig:vacuum}, right. The chamber is supplied with a combination of rotary and turbomolecular pumps to routinely reach pressures of $2\cdot10^{-6}$~mbar, despite of the chamber volume and the variety of feedthroughs for signals and cooling media. The pressure is measured with a penning/pirani sensor system. Special emphasis is put on operating the detector at temperatures below room temperature and hence, providing active cooling inside the vessel is mandatory.
-
+To characterize cooling media and to select a reliable concept of piping inside the vacuum, a dedicated setup was constructed, based on copper pipes and Swagelok fittings. The circuit inside the vacuum chamber was connected to a commercial cooling system (HUBER). With standard silicone oil as cooling liquid, circulated at atmospheric pressure, no leak was observed. However, at pressure of $10^{-2}$~mbar and one week of pumping residues of the coolant were spotted on the pipe connectors inside the vacuum. Finally, the coolant was changed to glycol, and no leaks were observed any longer, also when replacing the copper pipes bypolyurethane pipes. These studies underline the need of a careful preparation of reliable pipe interconnections and do suggest not to employ coolants which feature strong creeping, like silicone oil.
\begin{figure}[htb]
\centering
\includegraphics*[width=85mm]{report.eps}
- \caption{Left: IR picture at $10^{-4}$ $mbar$ and heater at 1.12~W/cm$^2$ on copper carrier. Right: full-size half-station heat-sink of the MVD station 0 located in the vacuum chamber.}
+ \caption{Left: IR picture, taken at $10^{-4}$ mbar, of a dedicated heater featuring 1.12~W/cm$^2$ attached to a copper carrier and heat sink, used to characterzie the setup. Right: Full-size half-station heat sink of the first MVD station located in the vacuum chamber.}
\label{fig:vacuum}
\end{figure}
+Outgassing of materials has to be kept at a minimum, both to not spoil the vacuum close to the target and to avoid contamination of surfaces. The setup allows to characterize coarse outgassing of detector components, like (flex) cables, adhesives or electronic components, by employing the so-called throughput method or the gas accumulation method \cite{Redhead}. However, outgassing measurements with higher accuracy request a large probe area compared to the setup area, and hence a dedicated setup.
+Evaluating the thermal management of the MVD modules in vacuum is one of the most pressing tasks to be assessed with the setup presented here. Emphasis is put on heat-sinks and sensor carriers based on high-performance materials like chemical vapor deposition (CVD) diamond and thermal pyrolitic graphite\footnote{These materials are selected due to their outstanding heat conductivity, allowing at the same time a minimum material budget, which represents another important constrain for the MVD.} (TPG). The evaluation is carried out by contact temperature sensors (DS1820) in combination with a high-resolution infrared camera positioned outside of the chamber, observing through a dedicated zincselenide window transparent for infrared. The contact sensors serve as a reference for the infrared-based characterization of the detector setup, and they allow at the same time for a proper calibration of IR camera with respect to the reflectivity of materials and reference measurements. To emulate the expected MVD-sensor heat dissipation, Kapton flexible heaters from OMEGA \cite{OMEGA} are glued on materials under
+evaluation, see Fig.~\ref{fig:vacuum}.
-
-
+It is planned to characterize in vacuum full-size detector prototypes like PRESTO (PREcursor of the Second sTatiOn), see \cite{PRESTO}, with a focus on the long-term operation of MVD modules in vacuum.
\begin{thebibliography}{9}
- \bibitem{PRESTO}
- M. Koziel et al., "PRESTO: PREcursor of the Second sTatiOn of the CBM-MVD." GSI annual report 2014.
+ \bibitem{PRESTO}
+ M. Koziel et al., "PRESTO: PREcursor of the Second sTatiOn of the CBM-MVD." GSI annual report 2014.
-\bibitem{Redhead}
+\bibitem{Redhead}
P. A. Redhead, ``Recommended practices for measuring and reporting outgassing data'',
National Research Council, p.~4, Ottawa ON K1A 0R6, Canada
-\bibitem{OMEGA}
+\bibitem{OMEGA}
OMEGA Engineering, INC. (www.omega.com)
%\bibitem{glycol}
%Aqua-Concept Gmbh, Germany (www.aqua-concept-gmbh.eu)
\end{thebibliography}
- \end{document}
\ No newline at end of file
+ \end{document}
\ No newline at end of file
+++ /dev/null
-\documentclass{JACoW-GSI-2014}
-\usepackage{graphicx}
-% forbitten: \usepackage{url}
-\usepackage[utf8]{inputenc}
-\usepackage{amsmath}
-\usepackage{amssymb}
-%% GSI Scientific Report 2013
-%% \setlength{\titleblockheight}{27mm} KG
-\setlength{\titleblockheight}{35mm}
-
-\begin{document}
- \title{Assessing the vacuum compatibility of the CBM micro vertex detector\thanks{Work supported by BMBF (05P12RFFC7), HIC for FAIR and GSI}}
-
- \author[]{G. Kretzschmar}
- \author[]{M. Koziel}
- \author[]{C. M{\"u}ntz}
- \author[1]{T. Tischler}
- \author[]{M. Deveaux}
- \author[1,2]{J. Stroth}
-
- \affil[1]{Goethe-Universität, Frankfurt, Germany}
- \affil[2]{GSI, Darmstadt, Germany}
-
- \maketitle
-
-The CBM micro vertex detector (MVD) will operate in a moderate vacuum of about $10^{-4}$ $mbar$ to minimize multiple scattering. The vacuum compatibility of the detector needs to be validated with respect to thermal management of the MVD-stations and their mechanical integrity during the design and prototyping phase. A dedicated vacuum vessel, located at the IKF Frankfurt, allows for systematic studies w.r.t. selection of material, detector operation and cooling in vacuum.
-
-The setup comprises a 260 liter stainless steel vacuum chamber with multiple flanges providing a flexible access to the interior part and the fitting of all MVD stations inside, see fig. \ref{fig:vacuum} right picture. The chamber is supplied with a combination of a rotary and a turbomolecular pump allowing to routinely reach the pressure of $2 \cdot 10^{-6}$ $mbar$, despite of the chamber volume and the variety of feedthroughs for signals and cooling media. The pressure is measured with two penning-pirani sensor systems. Special emphasis is put on safely operating the detector at temperatures below room temperature and hence, active cooling inside the vessel is mandatory.
-
-To test possible media for cooling and to select a reliable concept of piping inside the vacuum, a copper pipe of 6 mm outer diameter and 3 mm inner diameter was subdivided into smaller pieces and interconnected with Swagelok fittings to form in total about 1 m long cooling circuit. The circuit was next placed into the vacuum chamber and connected to the outside-chamber cooling system (HUBER). The standard Si-oil cooling liquid was then circulated at atmospheric pressure where no leak was observed and at pressure of $10^{-2}$ $mbar$, where signs of the coolant were spotted on the Swagelok connectors placed inside the vacuum. After excluding all mechanics-related reasons for observed leaks, the cooling liquid was changed to glycol. After this change no leaks were observed, also when replacing the copper pipes with polyurethane pipes. These studies underline the need of a careful preparation of reliable pipe interconnections and do suggest not to employ
-coolants which feature strong creeping, like silicon oil.
-
-Outgassing of materials has to be kept at a minimum, both to not spoil the vacuum close to the target and to avoid the contamination of surface. The setup allows to characterize outgasing of detector components, like (flex) cables, adhesives or readout boards. Outgassing rates of MVD components will be measured with the so-called throughput method or the gas accumulation method mentioned in \cite{Redhead} and the ratio of probe to vessel surface should be higher. This especially means to switch to a smaller vacuum vessel.
-
-The vacuum setup allows for evaluation of thermal management of the MVD components, i.e. heat-sinks and sensor carriers based on high-performance materials like chemical vapor deposition (CVD) diamond and thermal pyrolitic graphite\footnote{Materials selected due to their outstanding heat conductivity, allowing at the same time a minimum material budget, which represent another important constrain for the MVD.} (TPG). The evaluation is carried out by contact temperature sensors (DS1820) in combination with a high-resolution infrared camera positioned outside of the chamber (through a zincselenide window transparent for infrared). The contact sensors serve as a reference for the infrared-based characterization of the detector setup, and they allow at the same time for a proper calibration of IR camera with respect to the reflectivity of materials and reference measurements. To emulate the expected MVD-sensor heat dissipation, Kapton flexible heaters from OMEGA \cite{OMEGA} are glued on materials under evaluation, see figure \ref{fig:vacuum}.
-
-It is planned to characterize in vacuum full-size detector prototypes like PRESTO (PREcursor of the Second sTatiOn), see \cite{PRESTO}, with a focus on the longterm operation in vacuum.
-
-
-
- \begin{figure}[htb]
- \centering
- \includegraphics*[width=85mm]{report.eps}
- \caption{Left: IR picture at $10^{-4}$ $mbar$ and heater at 1.12~W/cm$^2$ on copper carrier. Right: full-size half-station heat-sink of the MVD station 0 located in the vacuum chamber.}
- \label{fig:vacuum}
- \end{figure}
-
-
-
-
-
-
-
- \begin{thebibliography}{9}
-
- \bibitem{PRESTO}
- M. Koziel et al., "PRESTO: PREcursor of the Second sTatiOn of the CBM-MVD." GSI annual report 2014.
-
-\bibitem{Redhead}
-P. A. Redhead, ``Recommended practices for measuring and reporting outgassing data'',
-National Research Council, p.~4, Ottawa ON K1A 0R6, Canada
-
-\bibitem{OMEGA}
-OMEGA Engineering, INC. (www.omega.com)
-
-
-\end{thebibliography}
- \end{document}
\ No newline at end of file
jspc29 / reports.git / commitdiff