Update: EMC R&D David Hitlin SuperB R&D Meeting September 25, 2008

Developments since Elba There were no meetings during June, July, August (Bi-weekly) meetings resumed last week Next meeting Tuesday, Sept. 30, then resume alternate Wednesdays at 8:30AM PST/5:30PM ECT Good news on the crystal geometry (Zhu) Good news on the beam test module (Asner) Progress on fast simulation (Cheng)

Forward endcap geometry We have been looking at two classes of crystal arrangement Vary crystal sizes with radius, starting with a front face dimension at small radius of ~ 1 Molière radius (à la BABAR) Use a single crystal size (à la CMS) There advantages and disadvantages to each geometry There is, however, an important constraint on both approaches

Candidate endcap crystal geometry Constraint: a 60mm diameter SIPAT boule must yield two crystals Stefano Germani

Cartesian endcap geometry (Frank Porter) All crystals are identical

Boule constraint There is an important constraint The SIPAT boule diameter is 60 mm To retrieve two crystals per boule with a back end as large as 25x25 mm requires the two crystals to be in opposite orientation In the Czochralski process, there is unavoidably a gradient in the dopant (Ce, Y) along the crystal length There is evidence that light output depends on Ce concentration Ren-yuan Zhu has been investigating this question in detail

This allows a yield of two crystals per SIPAT boule, which has a significant impact on the price/cc

Beam Test A good solution to the “catcher crystal” problem has presented itself INFN will provide €50K for LYSO crystals A proposal to DOE for Advanced Detector Research funds is in preparation A scintillating fiber/tile readout concept was presented at Elba by Gerald Eigen Appears to be a cost-effective, well-performing approach with geometric flexibility in a difficult space Many details to be worked out Readout device (SiPM ??) – neutron radiation dose is a question Rear endcap

5x5 Projective LYSO array with CsI(Tl) surround A 7x7 array is best, but it can be approximated by a 5x5 array surrounded by CsI(Tl) to catch the outer few percent of shower 16 radiation-damaged projective BABAR CsI(Tl) crystals may be available New: 12 CLEO-II non-projective CsI(Tl) crystals may available (four PD/crystal readout) CMS APD readout module 2 @ 5mmx5mm APD (10x10mm APDs are now available)