Vertex detector work at SU LHCb – RD50

1. Vertex detector work at SULHCb – RD50 Marina Artuso For the SU Velo group su velo group meeting

2. Sensor Work • Studies on VELO sensor • N-type substrates (PR04 – now being assembled into modules to be installed in LHCb • P-type substrates (PR05 – “spare” sensors that should be tested in the fall test beam) Sensor level studies: IV, CV, guard ring properties, interstrip resistance Electronics studies: comparison of different front end devices (noise, thresholds, timing) Resolution studies, module performance: laser test stand & test beams Test beam studies (june test [beam] – SU in charge of planning; fall test beam: alignment studies, p-type sensors,…) su velo group meeting

3. The VELO sensors • PR03 R-sensor (300 mm) cracked while no one was present. Cause unknown. • We have presently 2 mech & 1 electrical p-type PR05 sensor + 1 mech PR04 su velo group meeting

4. Wafer level measurements (Nasra) • IV on p-type sensors (rough measurement of depletion voltage + breakdown voltage) • Voltage drop across guard rings: • Tesla wafer diode test structures • Tesla wafer pixel devices • P-type sensors • Interstrip resistance (p-substrate/n-substrate VELO sensors) • CV measurements on Tesla and VELO sensors to confirm depletion voltage su velo group meeting

5. Wafer measurements (analysis) • Looking at GDS files, define geometry of guard ring & relate observation (gds viewer) • Simulation of interstrip resistance based on information on p-spray technology used (Nasra with Nabil’s supervision). • 1 day of ISE-TCAD training (June 13) su velo group meeting

6. Vacuum Test of VELO sensors • Goal: check the stability of operation in different vacuum conditions and at different levels of irradiations. • Measurement: IV characteristic of a sensor as received from the factory and after irradiation. • Strategy: • Measure IV in the probe station in the semiconductor lab at Syracuse university • Mount sensor on PCB carrier and repeat the measurement in air • Produce vacuum tank incorporating cooling capabilities to maintain irradiated detector at -7C & check mechanical properties of sensor mounted on PCB with mock-up • Measurement in vacuum at room temperature and with cooled detector • Irradiate sensor at IUCF [200 MeV p] • Repeat study on irradiated sensor • Radia/Nabil sensor measurements; Ray vacuum design; Nasra vacuum tests su velo group meeting

7. I I Nearest guard ring Bias ring Sensor under test Bias Backplane contact V (Keithley 277) The IV measurement • Goal: measure bulk current & lateral current (through the guard rings) • Planned set-up shown on the right (using 2 identical current measurement channels to probe the strip current and guard ring current) su velo group meeting

8. June beamless beam test su velo group meeting

9. Hardware/DAQ training day • Item to be covered: • CO2 cooling blow system (any real intervention has to have an expert present but there are general things a shifter has to look out for and know when to call an expert) • basics about vacuum system • Test box primer (Ray) • Scintillator trigger primer (Ray/JC) • how to operate PVSS control panels, acquire data, enter information in the log book • how to run a basic analysis program to check data integrity • Information needs to be posted on the web (JC) su velo group meeting

10. Module studies • Timing studies: • establishing the "fake" signal to noise behaviour of the module using test pulses and optimising the sampling time and test pulse timing (a three step operation) • Low noise operation: • check for variation in noise behaviour with different grounding schemes, in particular the attachment of the grounding strap • Look at the variation in noise behaviour with one side/two sides powered and clocked, and with one module/two adjacent/three adjacent modules powered. – • check the beetle behaviour with different trigger rates/ consecutive events triggering etc. • Operating condition sensitivity: • Bias voltage, vacuum performance, temperature sensitivity su velo group meeting

11. DAQ Studies • Test on the FPGA algorithms • multi-TELL1 and multi-module data to exercise the mechanics of the trigger and pattern recognition software • investigate the performance of the new event builder • Investigate Gaudi online implementation (JC) • Investigate the online aspects of the multi TELL1 readout to be improved from last time su velo group meeting

12. Software training day • Part I: • how to look at pedestals, noise, pipeline column number, error banks, with non zero and zero suppressed data, and with data where the pedestal banks are written out. • Part II: • how to do pattern recognition on cosmic data • Primer on online software (some lectures from first training day) su velo group meeting

13. Cosmic ray run • Calibration runs: gain calibration of ADC links • Take data to investigate occupancy, Landau distribution and tracking at different operating conditions (threshold studies…) • Expected event rate: su velo group meeting

14. Towards the future • A pixel detector for LHCb? • Superior pattern recognition capabilities • Fast data-push architecture • Easier trigger capabilities • Elements to be optimized for LHCb • Sensor (rad hard technology) • Readout electronics • Trigger algorithm su velo group meeting

15. Sensor • BTeV style pixel modules: • n-on-n (moderated p-spray) • Module available to SU in fall • n-on-p (RD50 common wafer) su velo group meeting

16. Electronics • Timing tests on FPIX2: main question can the clock run as fast as needed to run in a LHCb style environment • Identification of needed modifications and possible upgrade paths • Summer work: timing studies+ analog performance studies (Jeremy Chapman, JC, MA) • Module characterization with laser test stand (Koloina) su velo group meeting

17. trigger Three phases of R&D : • Simulations to establish trigger requirements and develop a baseline design: • Need program to obtain hit information from a telescope • Prototyping of algorithms and hardware components to establish performance metrics and determine cost estimates. • Optimizing the design to reduce cost of construction and maintenance, and to address commissioning and operations su velo group meeting

18. Deciding a starting geometry • Use a BTeV style station • Assuming a beam spread of 5.3 cm, and an acceptance between 15 mr and 390 mr, telescope with stations 4 cm apart seems OK. Cover forward region with 7 stations; maybe put 4 stations in the region for the very shallow tracks su velo group meeting

19. Towards an algorithm • Implement this geometry in LHCb simulation tree, • produce hit information in a format suitable for processing with common graphics programs • experiment with pattern recognition algorithms su velo group meeting

20. Towards a hardware implementation • Organize the sensor plane in subsections containing N readout chips (example: plane quadrants) • Benchmark timing of the algorithm • Finalization of the proposed solution: • L0 (BTeV style, most costly solution, no loss of physics in L0) • L0 (simple proto-track criteria, study whether background reduction suitable for next level of processing) • Refined L1 based on higher pattern recognition quality of pixel information. su velo group meeting

21. Concluding remarks • Summer milestones: • N-type versus p-type velo sensor studies • HV vacuum tests • Test beam data collection and analysis • Timing studies with FPIX2 • Commissioning of laser test stand • Planning next 3 years R&D su velo group meeting