Testbeam Post Mortem Immediate reflections on successes and failures Richard Plackett – University of Glasgow VELO Upgrade Discussion Meeting –1 st September 2010

2 Outline Summary of Beam Periods May June August Software Data Rates Discussion <-all the way through

3 Summary 25 th May to 6 th June (~1 week running) – Lost 5 days to Machine Development – Innovation with TDC and USB2 readout – DUTs: PR01, D04 (300um planar) 28 th June to 11 th July (~2 weeks running) – USB2 telescope – DUTs: PR01, 150um (C08) 20 th to 29 th August (~1 week running) – Lost startup to AMS – RELAXD telescope – Cooling – DUTs: BCB strip, Irradiated 3D pixel, FZ strip, MCZ strip, C08, D04

4 May Testbeam TDC Lots of effort from Sasha and Jan made the TDC work well We have seen time correlations from TDC and telescope Telescope 7 USB2 Timepix planes – synchronisation better than 2009 Rate slightly disappointing at ~5-7 fps, limited by multiple USBs Multiple scattering made worse by separation of telescope planes USB2s unstable at startup or changing modes or settings External shutter signal makes the system more flexible DUTs PR01 measurements successful, but could have done with more time to take extra data points D04 (300um) measurements as cross check to last year

5 June Testbeam Continuation from May (unexpected time available) DUTs PR01 Common mode problems made it difficult to see if we were taking data or not. Thin sensor measurements were a success and have now been processed Telescope As before, USB2 stability an issue Difficult to get USB2s as required by Prague (7 of 10 in existence) Organisation Due to short notice not many people available so hard work for all involved As before left system on long runs overnight

6 August Testbeam Irradiated Sensors Need to be careful about shipping, possible accidental breach of RP rules Bonding lab needs RP certification to work on irradiated sensors Standard gluing procedure incorporates a thermal cycle Cooling System Many thanks to Raphael and Jan who really got this working Not quite as portable as we had hoped but still held chips below freezing New monitoring and control system was slightly buggy, but helpful Data logging proved to be VERY valuable already Organisation Need to make having online analysis more of a priority Due to holidays, conference and exams this was difficult this time RELAXD Readout See next page…

7 August RELAXD Readout RELAXD Once operational ran much faster ~52fps!!!! Initial set up difficult and very expert only Hardware veto made driving shutter close to limit safe Good synchronisation as sets of 4 Timepix shared shutter signal 1 of 3 readouts very unstable, not able to achieve quite optimum resolution possible Treating chips as quads made equalisation and changing mode slow and an expert only procedure Switching to negative polarity for 3D sensors was a hardware procedure Missing regulator boards may have compromised threshold settings Software To get max frame rate had to use combination of Pixelman and RELAXDAQ Some Bugs and Instabilities due to newness of the system Uncompressed data format filled hard drive very quickly

8 Software - Overall Many thanks to Malcolm who has adapted analysis framework to accommodate lots of data format changes TELL/Beeetle/Vetra system is cumbersome to use and is difficult for non experts to get right – lots of instructions needed Updates to Pixelman for multiple window running helpful Further work is needed to make RELAXD a system that shifters can use

9 Data Rates TELL system currently has slower data rate than USB2 or RELAXD May and June took >20Million tracks (majority TELL1 running) but with some long overnights August (50% TELL1 running) took >50million tracks… Measurement of 3 strip DUTs and 4 pixel DUTs (3D repeated)

10 Conclusions Increase in data rate with RELAXD makes a big difference to what we can do in one week *BUT* need to make the system more stable and user friendly (to be more expert friendly) Cooling is now operational, need to be careful about making irradiated assemblies due to RP rules and heat cycles – long term planning Having a strong presence for online data analysis is very important