From: tischler Date: Sat, 15 Feb 2014 10:24:35 +0000 (+0100) Subject: Version 2, 15.02. X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=4ba9649cb112022910f18eea2b7560685078ef62;p=reports.git Version 2, 15.02. Christians comments included --- diff --git a/GSI_2014_TT_Layout_of_the_MVD/Layout_of_the_MVD.tex b/GSI_2014_TT_Layout_of_the_MVD/Layout_of_the_MVD.tex index 2c63540..10314a7 100644 --- a/GSI_2014_TT_Layout_of_the_MVD/Layout_of_the_MVD.tex +++ b/GSI_2014_TT_Layout_of_the_MVD/Layout_of_the_MVD.tex @@ -21,9 +21,9 @@ \maketitle -The Micro Vertex Detector (MVD) of the CBM experiment will be equipped with CMOS Monolithic Active Pixel Sensors developed at the IPHC, Strasbourg. This sensor technology will meet the constraints formulated by the physics cases the MVD will contribute to the measuremnents regarding radiation hardness, spatial resolution and read-out speed best at the time given. Recently developed sensor prototypes, \cite{1}, providing the sensor architecture to be used for the sensors to be integrated into the MVD allowed to revise the sensor arrangement within the acceptance of the MVD.\\ +The Micro Vertex Detector (MVD) of the CBM experiment will be equipped with CMOS Monolithic Active Pixel Sensors developed at the IPHC, Strasbourg. This sensor technology will meet the constraints formulated by the physics cases. The latest sensor prototypes, \cite{1}, provide the sensor architecture to be used for the sensors being integrated into the MVD, allowed for defining the sensor arrangement within the acceptance of the MVD.\\ -The MVD will consist of up to four detector stations to be positioned at $50 /100 /150 /200$ mm downstream the target. The construction of the fourth MVD station is currently under discussion. The assumed sensor dimensions of $30 \cdot 13$ mm$^{2}$ feature an in-active area of $3 \cdot 10$ mm$^{2}$ for the on-chip read-out electronics. This in-active area requires a double-sided positioning of the sensors on the MVD stations to achieve the optimum acceptance coverage. The thickness of the sensors will be $50\; \mu$m which requires dedicated customized sensor positioning tools.\\ +The MVD will consist of up to four detector stations at $50 /100 /150 /200$ mm downstream the target. The assumed sensor dimensions of $30 \cdot 13$ mm$^{2}$ feature an in-active area of $3 \cdot 10$ mm$^{2}$ for the on-chip read-out electronics. This in-active area requires a double-sided positioning of the sensors on the MVD stations to achieve the optimum acceptance coverage. A $500 \; \mu$m overlay of the active sensor areas optimizes this coverage for inclined tracks. The thickness of the sensors will be $50\; \mu$m which requires dedicated customized sensor positioning tools.\\ \begin{table}[!htbp] \centering @@ -42,13 +42,13 @@ The MVD will consist of up to four detector stations to be positioned at $50 /10 \label{tab:sensornumber} \end{table} -The operation of the MVD in the vacuum to minimize multiple scattering of the produced particles results in the mandatory cooling of the sensors. At the same time, the material budget of the MVD stations has to be limited due to its significant impact on the tracking and reconstruction efficiency. High performance carbon-based materials - offering the best combination of an excellent heat conductivity and a low contribution to the material budget of the MVD station - will be used as cooling support in the detector acceptance. For the stations positioned at $50$ mm and $100$ mm, $150\; \mu$m thin CVD diamond (CVD) carriers will be used as cooling support, while for the third and possible fourth MVD station carbon fibre-encapsulated Thermal Pyrolithic Grafite (TPG) is foreseen. The thickness of the carbon fibre-encapsulated TPG is $500\; \mu$m including two $60\; \mu$m carbon fibre plans. Outside of the active area, the constraints due to minimizing the material budget and the resulting multiple scattering are less stringent which allows to position actively cooled aluminum heat sinks. These are held by dedicated half station support structures levelling the different heat sink dimension of the stations, as shown in figure \ref{fig:overview}. The MVD half stations are positonend on base plates to allow the movement of the MVD apart the beam line while beam tuning and beam focusing. +The operation of the MVD in the vacuum to minimize multiple scattering of the produced particles requires an efficient cooling of the sensors. At the same time, the material budget of the MVD stations has to be limited due to its significant impact on the tracking and reconstruction efficiency. High performance carbon-based materials - offering the best combination of an excellent heat conductivity and a low contribution to the material budget of the MVD station - will be used as cooling support in the detector acceptance. For the stations positioned at $50$ mm and $100$ mm, $150\; \mu$m thin polycrystalline CVD diamond (CVD) carriers, \cite{2}, will be used as cooling support, while for the third and fourth MVD station $500\; \mu$m thick carbon fibre-encapsulated Thermal Pyrolithic Grafite (TPG), \cite{3}, is proposed, employing $60\; \mu$m carbon fibre sheets. Outside of the active area, the constraints due to minimizing the material budget and the resulting multiple scattering are less stringent which allows for positioning actively cooled aluminum heat sinks. These are held by dedicated half station support structures levelling the different heat sink dimension of the stations, as shown in figure \ref{fig:overview}. The MVD half stations are positonend on common base plates to allow the movement of the MVD apart the beam line while beam tuning and beam focusing. \begin{figure}[htb] \centering -\includegraphics*[width=75mm]{MVD_overview.pdf} -\caption{The overview of the MVD is depicted. For one of the two MVD half station groups is set to transparent to ease the visualization. The beam is coming from the right.} +\includegraphics*[width=87.5mm]{MVD_overview.pdf} +\caption{The overview of the MVD is depicted. For one of the two MVD half station groups is set to transparent to ease the visualization. The beam is coming from the left.} \label{fig:overview} \end{figure} @@ -59,7 +59,13 @@ The material budget limit for the first MVD station of $x/X_{0} \approx 0.3 \%$ %\begin{thebibliography}{99} % Use for 10-99 references \bibitem{1} -F. Morel et al. ``MISTRAL and ASTRAL: two CMOS Pixel Sensor architectures suited to the Inner Tracking System of the ALICE experiment'', 2014 JINST 9 C01026 +F. Morel et al. ``MISTRAL and ASTRAL: two CMOS Pixel Sensor architectures suited to the Inner Tracking System of the ALICE experiment'', 2014 JINST 9 C01026. + +\bibitem{2} +CVD diamond, Diamond Materials, http://www.diamond-materials.com. + +\bibitem{3} +K. Arndt, Talk at the ``Forum on Tracking Detector Mechanics"', June 2013, Oxford, UK. \end{thebibliography} diff --git a/GSI_2014_TT_Layout_of_the_MVD/MVD_overview.pdf b/GSI_2014_TT_Layout_of_the_MVD/MVD_overview.pdf index 79decd5..5aa1727 100644 Binary files a/GSI_2014_TT_Layout_of_the_MVD/MVD_overview.pdf and b/GSI_2014_TT_Layout_of_the_MVD/MVD_overview.pdf differ