Calorimetry

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 14GeV 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 14GeV , beams at KEK. All the test modules have the same cross section (2020 cm).  

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(B8%) 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=02.5Tesla 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.