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The JLC group has made two kinds of test modules corresponding to one unit of the hadronic part of the calorimeter(Fig.13), as reported at LCWS93. [4] The standard calorimeter is a sandwich-type lead and plastic scintillator(SAND); the second option is a lead/scintillating fiber calorimeter(LESFI). Both are so called compensating calorimeters providing the same energy deposit for electrons and pions(hadrons). At this workshop, K.Ishii presented the results of beam tests using 1tex2html_wrap_inline14214GeV electron and negative-pion beams at KEK. [26] The results are summarized in Tab.2.

Table 2: Beam-test results of the test calorimeter modules by 1tex2html_wrap_inline14214GeV tex2html_wrap_inline1829,tex2html_wrap_inline1831 beams at KEK. All the test modules have the same cross section (20tex2html_wrap_inline179920 cmtex2html_wrap_inline1425).  

For electrons, the LESFI and the fine sampling (F-)SAND fulfill the required energy resolutions, including the constant term. For pions, the large constant terms(Btex2html_wrap_inline14218%) were observed in both modules. The cause was speculated to be a lateral shower leakage, which will be checked by a beam test.

In order to readout the signals in a 2-Tesla solenoid field, three kinds of devices (fine mesh photomultiplier(FMPMT), hybrid photo-diode(HPD) and vacuum avalanche photo-diode(VAPD)) were also tested in a magnetic field of up to 2.5Tesla. While FMPMT and HPD were operational even in 2.5Tesla, HPD seems to be better because of the stable gains in B=0tex2html_wrap_inline14212.5Tesla and the uniform response for any direction of the magnetic field. Although the present readout uses wavelength shifters, a CDF-type tile/fiber readout [27] will be considered in the future for no gap between the modules.

Toshiaki Tauchi
Fri, Dec 20, 1996 02:24:05 PM