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Heavy Scintillating Glasses for Future High Energy Particle Physics Experiments

Heavy Scintillating Glasses for Future High Energy Particle Physics Experiments. Chun Jiang School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Tianchi Zhao University of Washigton Nov. 6, 2007. CALICE Analog Hadron Calorimeter for ILC.

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Heavy Scintillating Glasses for Future High Energy Particle Physics Experiments

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  1. Heavy Scintillating Glasses for Future High Energy Particle Physics Experiments Chun Jiang School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Tianchi Zhao University of Washigton Nov. 6, 2007

  2. CALICE Analog Hadron Calorimeter for ILC Prototype Stack 30 x 30 cm steel absorber plates, 2 cm thick for a 1 cm gap between steel plates Average density of the CALICE analog calorimeter is ~5.5 g/cm3 Active detector: Plastic scintillator tiles 5 cm x 5 cm, 0.5 cm thick Light collected by Wavelength Shifting Fibers Readout by Silicon photomultipliers

  3. MPPC MPPC MPPC MPPC GLD Calorimeter Design Examples Tungsten, lead or steel absorber plates plastic scintillator tiles or strips MPPC MPPC Hadron Calorimeter Electromagnetic Calorimeter

  4. Our Proposal To replace the structure of metal and plastic scintilaltor plates by scintillating glass blocks that glued together to form homogeneous modules. It will be - A total absorption calorimeter for optimum resolution - Can combine the functions of EM and Hadron Colorimeters A total absorption hadron calorimeter can have excellent energy resolution because it provide several ways to measure energies required to break up nuclei, which is mostly “invisible” in a sampling hadron calorimeter since such energy is mostly absorbed by the inactive metal plates.

  5. Two Options Option 1: A conventional scintillation calorimeter that reads the scintillation light only Hadron energy that is invisible in a sampling calorimeter can be recovered by observing ionization energies from heavy nuclei fragments, spallation protons, ’s released by fast neutron inelastic scatterings and recoiling nuclei due to fast neutron elastic scatterings, and energies released by thermalized neutrons captured by the calorimeter media Option 2: A dual readout calorimeter that reads the scintillation light and cherenkov light separately. Compensation for the invisible energy can be achieved by this method. See the reference http://ilcagenda.linearcollider.org/contributionDisplay.py?contribId=202&session Id=45&confId=1556

  6. Excellent Hadron Energy Resolution A total absorption hadron calorimeters can potentially achieve excellent energy resolution for both EM and hadron showers Energy resolution Note: It is important to choose the right calorimeter media so that fast neutrons can be absorbed quickly (< ~1 s) and locally and contribute to the energy measurements Fluka Study by A. Ferrari and P.R. Sala of INFN-Milan for a total absorption calorimeter with four different materials presented in calor2000 Integration time

  7. Calorimeter Technologies for HEP Historically, only electromagnetic calorimeters are total absorption calorimeters for high energy physics experiments. Hadron calorimeters are sampling calorimeters made of heavy metal absorber plates and active detector layers with very small energy sampling ratio (typically <<10%) A total absorption calorimeter was proposal for the D-zero detector at Fermi National Lab based on scintillating glass bars in the 1980’s. But that proposal was not adopted. Developing an appropriate scintillation material is the key for a total absorption calorimeter to become reality

  8. Basic Requirements Calorimeter total volume : on the order of 100 m3 • High density • Short radiation length • Short interaction length • Scintillation light properties compatible with the • readout method ATLAS hadron calorimeter CMS hadron calorimeter

  9. Scintillating Glasses as a Calorimeter Media for High Energy Physics • Scintillating glass is inexpensive compared to crystal scintillators • Light yield is normally less than 1% of NaI • light yield of scintillating glass can be several times higher • than the light yield of PbWO4 crystal used by CMS experiment

  10. Scintillating Glasses SCG1-C • Scintillating glass: SCG1-C with modest density was developed • in early 1980’s by Ohara Optical Glass Company in Japan • Major components: BaO 44% and SiO2 42% with 1.5% Ce2O3 • It is easy to fabricated and have good scintillation properties • SCG1-C glass was considered for the EM and hadron calorimeter • of the D-zero experiment at Fermilab in the 1980’s, but was not • adopted • SCG1-C was used in several HEP experiments as EM calorimeters • Density 3.5 g/cm3 is too low for our purpose • No thermal neutron isotopes, not good for hadron calorimeters

  11. Fluorohafnate Scintillating Glasses • Attempts were made to develop Fluorohafnate Scintillating • Glasses for CMS EM calorimeter by CERN’s Crystal Clear • Collaboration in the 1990’s • (HfF4-BaF2-CeF3) + (5% Ce2O3 doping) • Density is quite high 5.95 g/cm3 • Low scintillation light yield ~0.5% NaI in near UV region • Expensive and very difficult to make into sufficiently large size • No thermal neutron isotopes, not good for hadron calorimeters • Not good for our purpose

  12. Our Proposed BSGB Scintillating Glass • B2O3-SiO2-Gd2O3-BaO 30:25:30:15 • doped with Ce2O3 or other dopants • Chun Jiang, QingJi Zeng, Fuxi Gan,Scintillation luminescence of cerium-doped borosilicate glass containing rare-earth oxide, Proceedings of SPIE, Volume 4141, November 2000, pp. 316-323 • Density 5.4 g/cm3 is sufficient for an ILC calorimeter • Contains a large amount of thermal neutron isotopes • boron and gadolinium • Will capture thermalized neutrons in a short time and in close proximity to hadron showers providing a mean for recovering invisible energies in hadron showers

  13. Some Properties of the BSGB Glass

  14. Transmission Spectrum of GSGB Glass A: Base glass without doping B: GSGB glass with 5%Ce C: After radiation 14

  15. Fluorescence Spectrum of GSGB:Ce Glass 15

  16. Scintillation Light Yield (80 keV X-ray excitation) BSGB Glass 16

  17. Manufacturing Issues of Gadolinium Oxide Glasses 1. Conventional melting method with resistance furnace, reduction agents or reduction gases 2. Cost: Gd2O3 is more expensive than PbO, Bi2O3, Ce2O3, La2O3, etc, but cheaper than Yb2O3, Lu2O3, Ga2O3, GeO2, TeO2, etc. 3. Large block of Gd2O3 based scintillation glass with density of over 5.0g/cm3 can be fabricated. 17

  18. Future Plans (1) • Make samples for testing by Fermilab (Dr. A. Para), • University of Washington and Italian groups • 5 cm x 5 cm and 10 cm x 10 cm, 1 cm to 2 cm thick • If successful, supply ~ 20 liters of glass blocks for a • EM calorimeter module to be tested in the beam • at Fermilab 18

  19. Future Plan (2) Scintillating Glass for a Dual Readout Calorimeter • For dual read design (readout scintillation and Cherenkov light • separately) , the scintillating glass must have • Scintillation light spectrum peak > ~500 nm • and/or • Scintillation light decay time > ~100 ns • Investigate different doping for BSGB glass • - The Ce+3 doping is used to general fast short wavelength • scintillation light that is not necessary for an ILC calorimeter. • - Ce+3 doping must be made in a reducing atmosphere and is • difficult to control • - Longer and slower scintillation light is required for a dual • readout caloriemter 19

  20. Future Plans (3) • Investigate PbO-Bi2O3 scintillating glass • with high density of over 6.0-7.0g/cm3 and high transmission at shorter wavelength. 20

  21. Conclusions • The BSGB scintillating glasses with Ce2O3 is an excellent • candidates for total absorption calorimeters for colliders • at very high energies that can achieve good EM and hadron energy • resolution • Further studies are necessary to make samples for testing • BSGB scintillating glass with different doping with improved • properties and suitable for the dual readout calorimeter can be • developed 21

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