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First Results from Tracker 1 Cryostat Commissioning AFE/VLSB Firmware and Readout Cosmic Ray Setup Tracker Readout Software Trigger Timing Scan Alignment Light Yield Next Steps 1M.Ellis - VC113 - 17th July 2008
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Cryostat Commissioning Both cryostats cooled down very well and reached a temperature that allows all 4 cassettes to operate at 9.0 Kelvin. The lid heater alarms and VESDA smoke detection system have been hooked up to a relay that will kill the AFE power if any of the three alarm. An auto-dialler will call an expert (or the MOM) if any of the above alarms occur, or if either of the insulating vacua start to degrade. 2M.Ellis - VC113 - 17th July 2008
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AFE / VLSB Firmware New AFE and VLSB firmware from Fermilab is being used for the readout. An additional VLSB is providing an encoded clock signal that is fanned out to all 8 AFE boards. The readout is operating asynchronously, with the trigger coincidence signal being vetoed by the master VLSB to only allow a trigger to be produced in the correct live windows. 3M.Ellis - VC113 - 17th July 2008
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Cosmic Ray Setup The 25 waveguides were connected and the cassettes made light tight. At the moment there is a 2 inch layer of lead under the tracker to act as a momentum filter. The coincidence of two trigger scintillators (one above the tracker, one underneath the tracker and a layer of lead) provides the external trigger (which is a bit noisy). Some new trigger scintillators are being prepared at Fermilab which should increase the trigger rate and the trigger efficiency. 4M.Ellis - VC113 - 17th July 2008
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Tracker Readout At the moment we are using the Excel/Visual Basic DAQ developed at Fermilab. Hideyuki is working on a Linux based AFE initialisation code. Once that is working, we will check that the data taken looks the same and start to move to a Linux based AFE initialisation and DATE DAQ for readout. 5M.Ellis - VC113 - 17th July 2008
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Software The decoding and calibration files have been committed to G4MICE and the necessary unpacking code for the current data format. A new application – “R8CosmicTest” has been added which reconstructs the data and creates ROOT histograms and event display files for viewing using HepRApp. All plots in this talk can be reproduced by checking out the most recent version. 6M.Ellis - VC113 - 17th July 2008
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Trigger Timing Scan Need to get the delay between cosmic ray passage and AFE trigger signal correct at the level of 10- 20 ns. Scan over a range of delays, take data for a day and find delay with maximum light yield. 7M.Ellis - VC113 - 17th July 2008
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Trigger Timing Scan - Results 8M.Ellis - VC113 - 17th July 2008 Delay chosen: 862 ns Filled square – station 1 Triangle up – station 2 Triangle down – station 3 Open circle – station 4 Open square – station 5 Light Yield for each Station Average Light Yield for All 5 Stations
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Alignment The alignment started with the nominal values from the tracker design for the station spacing, central fibres, etc. These were fed into G4MICE and triplet residuals and tracking residuals used to spot any misalignments or inconsistencies. 9M.Ellis - VC113 - 17th July 2008
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Triplet Internal Residuals 10M.Ellis - VC113 - 17th July 2008 Stations 1 – 4 have residuals centred near 0 with no need for any alignment
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Triplet Residuals – Station 5 11M.Ellis - VC113 - 17th July 2008 Station 5 before adjusting the nominal values Station 5 after adjusting plane X
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Station Alignment Will check station spacing with Coordinate Measuring Machine (CMM) data, but for now assume the spacing is exactly as designed. At high momentum (i.e. no MCS), expect residuals to have an RMS of ~ 430 m in X and ~ 497 m in Y. 12M.Ellis - VC113 - 17th July 2008
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Track Residuals 13M.Ellis - VC113 - 17th July 2008 X – expect 430 m, see 466 m RMS Y – expect,497 m, see 549 m RMS Implies misalignments of order 100 m TRD Spec for Tracker alignment: 70 m
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Light Yield Light yield determined by plotting the distribution for each plane and each station (integrating over planes in a station) for clusters that were included in a good track. Some features (narrow peaks) in the plots for individual planes/stations are due to overflow of the ADC. Due to variations in the gain of the cassettes, these peaks move around as a function of plane/station. 14M.Ellis - VC113 - 17th July 2008
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Light Yield – All Stations 15M.Ellis - VC113 - 17th July 2008 Light Yield: ~ 11 PE
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Next Steps Add another layer of lead and continue data taking at the optimum trigger delay. Use CMM data to update station spacing and possibly transverse positions. Study light yield and efficiency for each station and each plane, and if sufficient statistics, as a function of position on the plane. 16M.Ellis - VC113 - 17th July 2008
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Finally – 100 Events with 5 point Tracks: 17M.Ellis - VC113 - 17th July 2008
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