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Quartz Plate Calorimeter Prototype

Quartz Plate Calorimeter Prototype. Ugur Akgun The University of Iowa APS April 2006 Meeting Dallas, Texas. Introduction.

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Quartz Plate Calorimeter Prototype

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  1. Quartz Plate Calorimeter Prototype Ugur Akgun The University of Iowa APS April 2006 Meeting Dallas, Texas

  2. Introduction • The calorimeters measure the energy of the neutral and charged particles. The particles deposit their energy into the calorimeters through creation and absorption processes. • The particles can interact primarily with: • Electromagnetic interaction • Hadronic (strong) interaction • The deposited energy can be determined in a variety of ways: – Ionization (Charge) • Excitation (Scintillation, Cerenkov) • The dense medium may be active or passive: – Homogeneous calorimeters – Sampling calorimeters

  3. Cerenkov Light Generation When high energy charged particles traverse dielectric media, a coherent wave front, which is called Cerenkov light, is emitted by the excited atoms at a fixed angle . The Cerenkov light is sensitive to relativistic charged particles (Compton electrons...) d2N/dxd=2 q2(sin2c / 2) =(2 q2/ 2 )[1-1/2n2] min = 1/n Emin ~ 200 KeV

  4. Quartz Calorimetry • The quartz detectors are intrinsically radiation hard. • The quartz detectors are sensitive to the electromagnetic shower components. • The quartz calorimeter is based on Cerenkov radiation and is extremely fast. It yields low but sufficient light. • All these make the Quartz calorimeters a very good option for the future hadron colliders

  5. Quartz Plate Calorimeter Prototype • We designed a quartz plate calorimeter prototype with 20 layers. • Each layer has 70 mm iron absorber and 5 mm quartz plates. • The cross section of the prototype is 20 cm x 20 cm. • The Cerenkov light is collected by wavelength shifting fibers and carried to the Hamamatsu R7525 PMT.

  6. The Fiber Geometry • 1 mm diameter Bicron wavelength shifting fibers are uniformly distributed on quartz plates. They absorb photons down to 280 nm, and emit 435 nm. • The fibers go ~20 cm out of the quartz plate.

  7. Calorimeter Response Linearity • For the sampling calorimeters the calorimeter response linearity is an important issue. Pathlength fluctuations and Landau fluctuations are the reasons of the detector nonlinearity. PRELIMINARY • The Geant4 simulations of our prototype calorimeter shows that • the detector response is linear up to 300 GeV.

  8. Energy Resolution • The energy resolution of a calorimeter is defined as; Where a - stocastic term, b - constant term and c- noise term • The resolution of the prototype is • simulated with different beam • energies. It yields; • a = 13.7 • b = 0.16 PRELIMINARY

  9. Shower Profiles • The hadronic showers are much broader and longer than the • electromagnetic showers. • Our prototype is more than 8 interaction length long. λint for iron • is 16.7 cm. 120 GeV Proton • The figure above shows the 3D simulation of the shower. Transverse • shower profiles show some leakage, but it is not Cerenkov capable • part of the shower. 10 cm radius contains ~100% of the Cerenkov • core of the shower.

  10. Transverse hadronic shower profile for different energies of proton beam Longitudinal hadronic shower profile for different energies of proton beam

  11. Fermilab Test Beam • We tested some layers of the prototype at the Fermilab Meson Test area with 120 GeV and 66 GeV positive beam. • All quartz plates with fibers are wrapped with Tyvek and black tape. • They are put into an aluminum frame which carries the PMTs, and wrapped again to make them light-tight. • All quartz plates and absorbers are supported by a rail system.

  12. Although we have only 6 layers, we got data at different absorber • depths (up to 70 cm of iron). • We developed our own data acquisition system with NIM, CAMAC • and LabView. • With limited number of layers we observed a full shower profile • at 120 GeV. • The 66 GeV has very low statistics.

  13. Conclusion and Future Plans • The “Generation 1” Quartz Plate Calorimeter Prototype showed promising preliminary simulation and test results. • Its portable design allows to test different configurations. • Since it is radiation hard, it can be used in the future collider experiments. • This summer we have one week beam time at CERN: • We will take electron and pion beams at different energies. Experimental measurement of electromagnetic and hadronic energy resolution of the prototype. • We will take beam at Fermilab M-Test area, in Fall 2006. • We plan to create a small ECAL unit in front of the prototype. References: Nucl. Instr. and Meth. A399, 202, 1997 Nucl. Instr. and Meth. A408, 380, 1998 J. Phys. G: Nucl. Part. Phys. 30 N33-N44, 2004 CMS NOTE 2006/044

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