Bambino: A Segmented Silicon Detector Array for TIGRESS
C.Y Wu, J. Becker, LLNL, and D. Cline, Rochester
Commissioning run of Bambino with two TIGRESS modules
The Bambino Si CD detector inside the Rochester target chamber


The Bambino segmented Si charged-particle detector array has been developed at Lawrence Livermore National Laboratory (LLNL) and Rochester for use with TIGRESS using beams from the TRIUMF/ISACII radioactive beam facility. The Bambino detector system has sufficient energy and position resolutions for the differentiation between projectile-like and target-like particles in Coulomb excitation experiments with TIGRESS. Such a system is essential in order to define the velocity vector of the $\gamma $-ray emitting nucleus and Doppler-correct the $\gamma $ rays detected in TIGRESS. Bambino consists of two annular silicon detectors having an active inner diameter of 22 mm and outer diameter of 70 mm and a thickness of about 150 $\mu m$. They are placed 3.0 cm from the target and provide solid-angle coverage of 1.15$\pi $ sr. Each has 24 sectors in $\theta $ for the anglular coverage between 20.1$^{o}$ and 49.4$^{o}$ and between 130.6$^{o}$ and 159.9$^{o}$ and has 16 sectors in $\phi $ for $2\pi $ coverage. Bambino is housed in a side-accessible spherical vacuum chamber designed and built at the University of Rochester in the second quarter of 2006. The Bambino system underwent extensive tests at both LLNL and TRIUMF in the second quarter of 2006 and, together with the Rochester target chamber, was successfully integrated into TIGRESS for the first radioactive beam experiment in July/August 2006. Planned improvements are addition of a 1000 micron CD-S2 detector to form an E-DeltaE telescope as well as a factor of two improvement in the phi resolution in order to reduce the Doppler broadening.