ATLAS Muon Spectrometer and EE Chamber Commissioning. Kareem Hegazy University of Michigan Advisors: Bing Zhou, Tiesheng Dia , Junjie Zhu Commissioning: Lulu Lui , Rex Brown, Eric Seabron , Kareem Hegazy August 11, 2011. Importance of the Muon Detection.
University of Michigan
Advisors: Bing Zhou, TieshengDia, Junjie Zhu
Commissioning: Lulu Lui, Rex Brown, Eric Seabron, Kareem Hegazy
August 11, 2011
The muon ionizes the gas and the electrons drift towards the high voltage wire which creates a signal used to find the drift time.
From the drift time we can only find the drift radius. Thus we need multiple tubes to reconstruct a track tangent to all the drift radii.
The signal from the drift wires goes to front end electronics where it is converted to digital signal and partially analyzed.
The data is then sent to the MROD where it goes through higher level triggers and saved if it passes all the triggers.
* It’s important to commission the electronics, otherwise the DAQ would not receive the raw data necessary to make calculations for analysis.
DAQ and Analysis
Number of hits vs. Time
Relates drift time to drift radius
By constantly running electronics tests for 10 days straight we make sure that all the electronics can handle higher rates of data acquisition than necessary. Additionally this burns in the electronics so they will perform better and more reliably in ATLAS.
The Injection Scan measures the readout channelefficiency and cross talk between channels on Mezzcards by using its calibration signals. Each channelcorresponds to a tube.
• The efficiency is found by checking if the channelhas hits when the signal was sent to it.
• When the signal is sent the activity on otherchannels is measured to find the cross talk.
• Large cross talk can make one channel register ahit when it did not and thus ruin the
measurements. Also, with low injection efficiencythe channel may be dead and not register when it is
supposed to, therefore it must be replaced.
The Linearity Scan measures the electronics’timing as well its timing resolution.
• A certain time is set and we measure howwell the electronics send a calibration at thattime.
• The time resolution is measured at a fixedtime with multiple measurements.
• Time measurements are very important
because they allow us to reconstruct the trackbased upon the RT function and find the PT.
To account for inherent noise the signalmust pass a -50 mV threshold to registeras originating from a muon. Due to theirmaking, each channel has a different offset and must be accounted for.
• The voltage offsets are measured tomake sure they are not too large.
• Since every channel has a different
offset, the pattern of all the offsets createa finger print for the Mezz Card. Thispattern is compared to a data base andchecked to see if each Mezz Card is where
it should be.
• Since each Mezz Card is different, if onewas in the wrong place all the
measurements would be thrown off.
The Gain Scan checks the electronics ability tomeasure charge by comparing a known signal to a measured signal.
• A known signal is sent from the computerwhere the leading and trailing edge ismeasured by the electronics.
• The measured results are compared to theknown signal to find the electronics’ precision.
Muon Drift Tubes (MDT)