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A Digital Hadron Calorimeter ?. Vishnu V. Zutshi NIU/NICADD. The proposal. Development of New Hadronic Calorimetery Technology G. Blazey, D. Chakraborty, A. Dyshkant, M. Martin, V. Rykalin, V. Zutshi NIU/NICADD
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A Digital Hadron Calorimeter ? Vishnu V. Zutshi NIU/NICADD
The proposal Development of New Hadronic Calorimetery Technology G. Blazey, D. Chakraborty, A. Dyshkant, M. Martin, V. Rykalin, V. Zutshi NIU/NICADD A. Brandt, K. De, A. White, J. Yu UTA Arrive at a realistic cost estimate for one of these devices
From analog to digital • Eflow seems to be a promising option for improving jet resolutions significantly • ALEPH and CDF have successfully used it • Requires a high granularity calorimeter • Digital hadron calorimeters: high granularity at affordable price ?
General Considerations • Granularity (energy and resolving power) • MIP recognition • Absorber density (optimize shower lateral size) • Depth • Matching to EM calorimeter • Readout (2d preferred to strip type) • Minimal intrusions
Analog and Digital 20 GeV pions in SD
On the software side of things • Prototype simulations: try out different cell shapes parameterized losses from test stand hoping to do this in GEANT4 framework • Event generation and LC detector simulation • Eflow algorithm development starting with the EM section
The Algorithm (cal-seeded) • Layer-by-layer clustering based on a search for local maxima • Cluster definition based on nearest neighbour • Track extrapolation through the calorimeter picking clusters in its path • EM/HAD. Charged/neutral discrimination • Understanding of errors involved with the tracking and calorimetric measurements
Sanity Checks clusters hits
Initial concept (scintillator-based) Four concentric layers of towers (7 stacks of 6-12 cells to a tower) formed with hexagonal cells. Start with 9cm2 cell.
Initial concept (scintillator-based) • Conversion to current: VLPC’s APD’s MRS’s PMT’s • Cost per channel v/s S/N
Test stand Cell with WLS fiber irradiated by a radioactive or LED WLS fiber connected to clear fiber which is connected to a photodetector (PMT’s, VLPC’s etc.) Output measured by a Pico ammeter
Test goals Find minimum area/thickness of cell Find minimum length of WLSF Measure signal losses at the WLSF to clear fiber transition
With VLPC readout MIP signal 9mm thickness,0.5mm fiber,2optical connectors
Initial concept (gas-based) • GEM approach • Developed initially for MSGC’s • Can be used with printed circuit readout • GEM’s with gains above 104 and spark probabilities < 10-10 have been developed • Reasonably fast operation • Relatively low HV
Issues/concerns (gas-based) • Cost of GEM layers • Lifetime/damage to layers • Effects of highly ionizing particles • Gas(es) ? • Mechanical stability of GEM gaps/supports • Cross-talk • …..
Summary • Single cell characterization studies have begun • GEM based feasibility studies starting soon • Event generation and simulation server ready • Setting up for GEANT4 based prototype simulation studies • Eflow algorithm development underway