1. CMS Tracker: Detector Control Units & Tracker Monitoring My Summer Student project (A contribution to:) Fatima Kajout 11 th of August 2003Student Session 2003

2. detectors Silicon detectors ~10 000000 detectors strips => A lot of temperature monitoring to do! Front End Readout, Control and Monitoring Units The CMS Tracker: Front End Control and Monitoring Student Session 2003

3.  Measures and monitors slowly varying analogue signals; i.e.: Temperatures, low voltages, detector currents,…  2*2 mm 2 chip; power consumption  50mW  Contains an 8-channel, 12 bit ADC,…  Provides 2 bias currents for powering temperature probes  Will be mounted on every module hybrid where it will monitor: - Internal temperature probes, external temperature probes, voltages and currents. DCU Detector Control Unit Student Session 2003

4. Agenda Project Outline Hardware and Objectives Software and Objectives (1) Software and Objectives (2) Architecture Validation Conclusions Student Session 2003

5. Project Outline The project aimed to build the tools needed to collect DCU data, store them into a permanent database, retrieve all or part of the data, and finally display and analyze them. An evaluation of the temperature and voltage measurement spread was also made. The project aimed to build the tools needed to collect DCU data, store them into a permanent database, retrieve all or part of the data, and finally display and analyze them. An evaluation of the temperature and voltage measurement spread was also made. A prototype system with 12 DCU ASICs has been installed and used for tests. A prototype system with 12 DCU ASICs has been installed and used for tests. Software technologies used are: Java, C++, SQL, mySQL and PAW. Software technologies used are: Java, C++, SQL, mySQL and PAW. Student Session 2003

6. Hardware and Objectives Prototype tests: no system of such size (“of the CMS Tracker”) can be assembled without exhaustive prototype work, followed by scalability studies that should validate the proposed architecture even when the number of modules grows by orders of magnitude, as in our case. I have set up a system with 12 DCU chips as a starting point. Performance measurements are foreseen. Prototype tests: no system of such size (“of the CMS Tracker”) can be assembled without exhaustive prototype work, followed by scalability studies that should validate the proposed architecture even when the number of modules grows by orders of magnitude, as in our case. I have set up a system with 12 DCU chips as a starting point. Performance measurements are foreseen. Student Session 2003

7. Measurements and calibration of 12 DCUs We used a set of 8 very-well measured resistors which simulated one thermistor at different temperatures (from –40 to 30 0 C). DCUcts Rin Temperature Steinhart-Hart equation: 1/T = a*ln(Rin) ³ +b*ln(Rin) ² + c*ln(Rin) +d Calibration linear formula: Rin = offset + scale*DCUcts

8. Converting from DCU counts to Ohm Clearly, there is a non-negligible spread in the offset values. It is still to be seen whether this influences the temperature measurement to the point of requiring a set of separate calibration constants for each DCU. Clearly, there is a non-negligible spread in the offset values. It is still to be seen whether this influences the temperature measurement to the point of requiring a set of separate calibration constants for each DCU. The present plots show the offset distribution and the scale factor distribution for the 12 DCU under test. The formula used is, of course,Counts = Offset + Scale * Resist The present plots show the offset distribution and the scale factor distribution for the 12 DCU under test. The formula used is, of course,Counts = Offset + Scale * Resist Although the spread is smaller, a non- uniformity in this calibration constant is as dangerous as one in the offset. Although the spread is smaller, a non- uniformity in this calibration constant is as dangerous as one in the offset. At –30 and +30 0 C, the RMS is ~ 1.2% of the mean value, i.e. for the same resistance value the measurements would vary ~ 1.2% (which is ~.5 0 C at +30 0 C and less at lower temperatures.)

9. Test temperature distribution This plot shows, for all 12 DCU chips tested, the reconstructed temperature for the 8 resistors used to simulate thermistors. It is clear from this plot that with increasing temperatures the measurements become less accurate. This is due to the non-linearity of the thermistor characteristic: the higher the temperature, the less the value of the resistance changes for an equal temperature step. Note that we will operate the CMS Tracker at –20° C => nice!!! Student Session 2003

10. Software and Objectives (1) Software and Objectives (1) Database design: a proper definition of the tables and their relationships is mandatory in a project of this size. Therefore, I have studied the problem and derived tables in the third normal form, as recommended by IT literature. Database design: a proper definition of the tables and their relationships is mandatory in a project of this size. Therefore, I have studied the problem and derived tables in the third normal form, as recommended by IT literature. Student Session 2003

11. Measurement Value Timestamp 1 1 1 1 Sensor Id Location Id ref 1 1 NN Each measurement entity comprises: a Value (an integer number produced by the analogue to digital conversion process); a Value (an integer number produced by the analogue to digital conversion process); a Timestamp (an integer number encoding the date and time at which the measurement was taken); a Timestamp (an integer number encoding the date and time at which the measurement was taken); a Sensor Id (a reference to a Sensor entity in a separate table); a Sensor Id (a reference to a Sensor entity in a separate table); a Location Id (a reference to a Location entity in a separate table); a Location Id (a reference to a Location entity in a separate table); Database design Student Session 2003

12. Software and Objectives (2) Interface design: in order to be of any use, a database system must offer interfaces that are easy to use and effective. Given the present database structure, the very first interface needed will be the one that allows to read the list of existing sensors and add to it. Interface design: in order to be of any use, a database system must offer interfaces that are easy to use and effective. Given the present database structure, the very first interface needed will be the one that allows to read the list of existing sensors and add to it. We can: Consult a=0.005;b=0.002;c=0.014;d=0.014 Sensor-Type Table Current 1 Voltage 1 Thermistor 1 Description Algorithm Steinhart-hart equation Thermistor 2 Student Session 2003

13. Architecture Validation The DCU prototype system will be also used to validate the proposed general scheme for the monitoring of Tracker environmental parameters. In particular, one should establish whether individual DCU chips need calibration constants, or a single set can be used without excessive loss of accuracy. The DCU prototype system will be also used to validate the proposed general scheme for the monitoring of Tracker environmental parameters. In particular, one should establish whether individual DCU chips need calibration constants, or a single set can be used without excessive loss of accuracy. Student Session 2003

14. Conclusions What we wanted to do: Gather DCU DATA and Gather DCU DATA and Store Store Retrieve Retrieve Display Display Analyze Analyze How we accomplished it: Prototyping a system with 12 DCUs and Prototyping a system with 12 DCUs and Performed measurements and calibration (used predevelopped software for the CMS Trackers) Performed measurements and calibration (used predevelopped software for the CMS Trackers) Designed a new, improved database Designed a new, improved database Designed a graphical interface Designed a graphical interface Next steps: Performance evaluation Performance evaluation Architecture validation Architecture validation Finalize database Finalize database Student Session 2003

15. Any question? Thank you! Student Session 2003