From: Michael Wiebusch Date: Thu, 5 Feb 2015 16:38:07 +0000 (+0100) Subject: preliminary report for front-end electronics X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=3789c1d1f087f6203e87d8d5ebe1334fa5ba3b2b;p=reports.git preliminary report for front-end electronics --- diff --git a/GSI_2015_JM-MW_MVD-Electroncis/JACoW-GSI-2013.cls b/GSI_2015_JM-MW_MVD-Electroncis/JACoW-GSI-2013.cls new file mode 120000 index 0000000..ae28ddc --- /dev/null +++ b/GSI_2015_JM-MW_MVD-Electroncis/JACoW-GSI-2013.cls @@ -0,0 +1 @@ +../JACoW-GSI-2013.cls \ No newline at end of file diff --git a/GSI_2015_JM-MW_MVD-Electroncis/current_digital.png b/GSI_2015_JM-MW_MVD-Electroncis/current_digital.png new file mode 100644 index 0000000..22f1f74 Binary files /dev/null and b/GSI_2015_JM-MW_MVD-Electroncis/current_digital.png differ diff --git a/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.pdf b/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.pdf new file mode 100644 index 0000000..6da6928 Binary files /dev/null and b/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.pdf differ diff --git a/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.tex b/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.tex new file mode 100644 index 0000000..11717ee --- /dev/null +++ b/GSI_2015_JM-MW_MVD-Electroncis/mvdelectronics.tex @@ -0,0 +1,95 @@ +\documentclass{JACoW-GSI-2013} +\usepackage{graphicx} +\usepackage{url} +\usepackage[utf8]{inputenc} +\usepackage{amsmath} +\usepackage{amssymb} +%% GSI Scientific Report 2013 +%% \setlength{\titleblockheight}{27mm} KG +\setlength{\titleblockheight}{35mm} + +\begin{document} +\title{The CBM MVD read-out electronics\thanks{Work supported by +BMBF (05P12RFFC7), HIC for FAIR and GSI}} + +\author[1]{J. Michel} +\author[1]{M. Wiebusch} +\author[]{the CBM-MVD collaboration} +\affil[1]{Goethe-Universität Frankfurt} + +\maketitle +\section{electronics} +The CBM Micro-Vertex-Detector (MVD) front-end electronics serve as an intermediating +device between the Monoilithic Active Pixel Sensors (MAPS) and the DAQ system +(based on the TRB3 system developed by HADES). +In the current connection scheme, one TRB3 FPGA board can support up to 16 sensors of type "MIMOSA26" +in parallel. + +These custom-built PCBs are necessary to supply the sensors with electrical power +and to convert between different digital signal standards. The central element of the +front-end electronics is the converter board. In addition to remote controlled power supplies, +signal switches and drivers, it features an ADC section to monitor the sensor’s momentary +electrical parameters. + +The sensors have to be supplied with a sensitive external biasing voltage, the so-called clamping voltage, +which gets distributed to all sensor pixels. +Several generation and distribution schemes were implemented to +investigate which setup results in the best noise performance. + +\section{measurements} +The MIMOSA26 provides a test mode to measure the discriminator transfer function\footnote{The firing +probability of a binary pixel as a function of discriminator threshold; usually has the form +of a sigmoid function.} of all pixels. The slope steepness is directly related to the temporal +noise of the detector. + +The read-out FPGA desgin was extended to operate and read out the sensor in this test mode. +The recorded data yields valuable information about the noise performance of the detector +hardware. To evaluate these data a dedicated analysis software was written. +Noise tests with MIMOSA26 are ongoing. However, preliminary results concerning the influence +of the clamping voltage suggest that it is beneficial to generate this reference voltage as +close to the sensor as possible and to use decoupling capacitors, if possible, next to the +bonding pads on the flex print cable. + +Furthermore the ADC section on the converter board can be used to perform systematic scans +in order to characterize the sensors. As an example of such an automatic scan, Fig. \ref{current_digital} +shows the dependence of the sensor's current consumption on the discriminator threshold setting. + +\begin{figure}[ht] +\centering +\includegraphics*[width=70mm]{current_digital.png} +\caption{The current consumption (digital VCC) of a MIMOSA26 sensor as a function of the discriminator threshold. +Data were acquired with monitoring devices integrated into the front-end electronics.} +\label{current_digital} +\end{figure} + +% \section{software development} +% In order to operate the MVD test setup, the MVD user software handles the +% coordination of data taking and continuous monitoring of sensor parameters (power consumption, +% temperature, etc). Furthermore it allows for convenient editing of sensor and electronics settings. + +\section{laboratory instrumentation} +When characterizing MAPS sensors, it is desirable to investigate the temperature dependence of certain +sensor parameters. Until recently such tests could only be done using a large cooling system which +circulates silicone oil through a cooling block to which the sensors under test are attached. +This set-up was greatly reduced in size, while at the same time improved in usability. +The sensors are now operated on a small copper platform which is cooled with a peltier element. A PID +controller implemented on a microcontroller senses the temperature of the platform by means of a onewire temperature +sensor and regulates the current through the peltier element. The device features a small display and a +simple user interface, alternatively it can be remote controlled via a USB connection. + +\section{Presto} +Current activities focus on bulding a demonstration version\cite{presto} of a quadrant of one of the rear stations of the MVD. +For now, MIMOSA26 MAPS are used in this project though they do not qualify to be used in the final detector. +Parts of the front-end electronics are currently redesigned to fit the spacial constraints of the set-up. + + +\begin{thebibliography}{9} + +\bibitem{presto} +Tobias/Michal - something on Presto, this issue. + + +\end{thebibliography} + +\end{document} +