Cold Strangelets Formation with Finite Size Effects in High Energy Heavy-Ion Collisions

We have studied the phase diagram and evolution of a strangelet in equilibrium with a finite hadronic gas. Significant finite size modifications of the phase diagram are found and their parameter dependences are studied. With the inclusion of finite size effects we have also been able to obtain the detailed properties of the cold strangelet emerging in the final stage of the isentropic expansion of a finite strange fireball in high energy heavy-ion collisions.Comment: 19 pages(RevTex), 11 Postscript figures; To appear in Phys. Rev.

Tracking with heavily irradiated silicon detectors operated at cryogenic temperatures

In this work we show that a heavily irradiated double-sided silicon microstrip detector recovers its performance when operated at cryogenic temperatures. A DELPHI microstrip detector, irradiated to a fluence of $\sim\,4\times 10^{14}$ p/cm$^2$, no longer operational at room temperature, cannot be distinguished from a non-irradiated one when operated at $T<120$~K. Besides confirming the previously observed `Lazarus effect' in single diodes, these results establish for the first time, the possibility of using standard silicon detectors for tracking applications in extremely demanding radiation environments

Time of flight measurements with hadronic showers

We present the results obtained from measurements of the arrival time of hadronic particles in a segmented scintillator-uranium calorimeter which was equipped with dedicated time of flight scintillator hodoscopes in depths of 0.75, 1.5, 2.25, 3.0 and 4.5 $\lambda_{int^-}$Gaussian shaped time resolutions with $\sigma \approx$ 90 ps were obtained with $\pi^−$ beams of 30 GeV/ c and 70 GeV/ c momentum. We discuss to what extent non-Gaussian tails can be removed while keeping a reasonably high efficiency