ALiBaVaA brief overlook of Liverpool A brief overlook of Liverpool software changes, common software changes, common

issues and questions.issues and questions.

A. Affolder, A. Greenall, I. Tsurin, G. Casse, V. Chmill, M. Wormald, H. Brown

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Overview of the TalkOverview of the Talk

This talk will cover This talk will cover some of the issues some of the issues we’ve seen in we’ve seen in Liverpool with the Liverpool with the Alibava system, and Alibava system, and how we solved themhow we solved them

Also covers Also covers commonly commonly encountered issuesencountered issues

Brief introduction to Brief introduction to the analysisthe analysis

Discussion on Discussion on calibrating the systemcalibrating the system

A look at some of the A look at some of the important additions in important additions in the Liverpool macro the Liverpool macro and their applications and their applications (specifically with (specifically with debugging the debugging the system)system)

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Introduction to the AnalysisIntroduction to the Analysis More detail available at More detail available at

http://tinyurl.com/alibavhttp://tinyurl.com/alibavaa or twiki or twiki

Most important canvas Most important canvas is the one on the right, is the one on the right, which is generic to all which is generic to all Alibava macrosAlibava macros

Please note that x-axis Please note that x-axis on the Landau is on the Landau is actually ADCs not actually ADCs not electrons! We have electrons! We have manually coded out the manually coded out the gain so we measure a gain so we measure a result in ADCs and result in ADCs and convert by hand to convert by hand to electrons.electrons.3

Known IssuesKnown Issues

Only a small number of known issues Only a small number of known issues with the Alibava system:with the Alibava system: 1) Running the Beetle chip on non-1) Running the Beetle chip on non-

default settingsdefault settings 2) Calibration (using the internal 2) Calibration (using the internal

calibration pulse) on non-default calibration pulse) on non-default settingssettings

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Some brief definitionsSome brief definitions

Gain – Number of electrons we obtain Gain – Number of electrons we obtain per ADC. Very dependent (~50%) on per ADC. Very dependent (~50%) on the initialization settings usedthe initialization settings used

Peak of the pulse shape – a ten Peak of the pulse shape – a ten nanosecond window (peak +/- 5 nanosecond window (peak +/- 5 nanoseconds) around the highest nanoseconds) around the highest value of the pulse with respect to value of the pulse with respect to time. This cut is used for the Landau time. This cut is used for the Landau spectrum on the analysis canvas.spectrum on the analysis canvas.

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Initialization Settings - Initialization Settings - CharacterizationCharacterization

Different settings correspond mainly Different settings correspond mainly to front shaper voltage; Default – 0V, to front shaper voltage; Default – 0V, 'Kazu' (LHCb VELO testbeam 'Kazu' (LHCb VELO testbeam settings) - 1V.settings) - 1V.

Dramatic signal to noise effect; 45 Dramatic signal to noise effect; 45 on default, 75 on Kazu.on default, 75 on Kazu.

We decrease noise from 700 We decrease noise from 700 electrons to 300 electrons.electrons to 300 electrons.

Dramatic change in signal to noise Dramatic change in signal to noise ratio means we can see signal at ratio means we can see signal at lower voltageslower voltages

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Loading Initialization Loading Initialization SettingsSettings

There is an interactive settings tab in There is an interactive settings tab in the GUI for the Beetle chip where you the GUI for the Beetle chip where you pass the values you wantpass the values you want

However, this does not load the settings However, this does not load the settings onto the chip! It generates a last.ini in onto the chip! It generates a last.ini in the /bin folder for you to load on next the /bin folder for you to load on next time.time.

Load settings by ./alibava-gui Load settings by ./alibava-gui settings.inisettings.ini

Pre-made settings files and pulse graph Pre-made settings files and pulse graph samples available on website/Twiki.samples available on website/Twiki.

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Difference Between Difference Between SettingsSettings

Note the Pulse Shapes

Compare signal spectrums too

Default Settings Kazu Settings

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Calibration IssuesCalibration Issues

The internal calibration pulses are The internal calibration pulses are timed in well for default settings (see timed in well for default settings (see prior time spectra). This gives us prior time spectra). This gives us 24,000 e- from 300 microns of silicon 24,000 e- from 300 microns of silicon (as expected) at both warm and cold (as expected) at both warm and cold temperatures.temperatures.

When we move the time peak, we When we move the time peak, we sample too early in the peak which sample too early in the peak which artificially inflates our gain (same artificially inflates our gain (same number of electrons for significantly number of electrons for significantly lower ADC values). See next slidelower ADC values). See next slide

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Calibration Timing IssueCalibration Timing IssueTiming of the calibration pulse is a big issue. We assume full charge collection but measure these off peak (less ADCs) which cause us to get more e-/ADC than expected.

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Calibration SolutionCalibration Solution To get around this problem we To get around this problem we

calibrate using unirradiated sensors calibrate using unirradiated sensors of known thicknesses, and a Sr-90 of known thicknesses, and a Sr-90 source to work out the gain at given source to work out the gain at given temperatures and Beetle temperatures and Beetle initialization settings.initialization settings.

Across several daughterboards the Across several daughterboards the gain is consistent to +/- 2%. [62.11, gain is consistent to +/- 2%. [62.11, 61.14, 63.61 e-/ADC]61.14, 63.61 e-/ADC]

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Liverpool Macros Liverpool Macros Available on Available on my websitemy website

Additional functionality provided mainly Additional functionality provided mainly in the form of:in the form of: A) Variable bin range fitting for the Landau A) Variable bin range fitting for the Landau

spectrumspectrum B) Distribution of hit location (channel B) Distribution of hit location (channel

number) versus frequency – helpful number) versus frequency – helpful debugging tooldebugging tool

C) Variable time slice analysis on Landau C) Variable time slice analysis on Landau (important for different initialization settings)(important for different initialization settings)

D) MaskingD) Masking

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Unmasked hit locations

Masked hit locations

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Variable Bin Range Variable Bin Range FittingFitting Allows us to not fit over Allows us to not fit over

the noise region, and to the noise region, and to stop the fit before it gets stop the fit before it gets too far into the tail, too far into the tail, where few events can where few events can distort our fits.distort our fits.

Results taken using the Results taken using the statistics box (provided statistics box (provided the gain was calculated the gain was calculated via the statistics box) is via the statistics box) is consistent with data consistent with data taken from the peaks. As taken from the peaks. As long as the method used long as the method used is consistent then the is consistent then the values are 100% values are 100% consistentconsistent

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Summary and FutureSummary and Future The Alibava system is a The Alibava system is a

fully functioning fully functioning readout system with readout system with associated offline and associated offline and online analysis alreadyonline analysis already

Only two known issuesOnly two known issues Easily adaptable Easily adaptable

depending on institute depending on institute requirements as well! requirements as well!

Less electronics Less electronics required as compared required as compared to SCT-128to SCT-128

Within our experiences Within our experiences at Liverpool we have at Liverpool we have confidence in the confidence in the results produced by results produced by the macro suite the macro suite providedprovided

Signals correspond to Signals correspond to previously measured previously measured sensors using SCT-sensors using SCT-128A.128A.

Pulse shapes agree Pulse shapes agree with independent with independent measurements, etcmeasurements, etc

Would be beneficial if Would be beneficial if more people signed up more people signed up to Alibava mailing listto Alibava mailing list15