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The digital pulse shape data acquisition (DAQ) system used by the large area telescopes of the 4π-multidetector CHIMERA requires transferring large amount of data to the computer. This is necessary so that the same information can be extracted from the detector pulses as in previous analog based systems. To overcome this problem, we have used a sampling ADC-board equipped with two TigerSHARC digital signal processors. The board receives the data and reconstructs the event parameters online. The data volume is significantly. reduced by transmitting to the DAQ only the reconstructed event parameters. [ABSTRACT FROM AUTHOR]

The capability of digital pulse shape technique to acquire data from CHIMERA detection cells (Si-CsI(Tl) telescopes) has been evidenced in our previous works. We have now applied this technique to the charge discrimination of the products stopped in the silicon detectors. Large area totally depleted CHIMERA planar silicon detectors (5 cm × 5 cm area, 300 µm thick) in both rear and front side injection have been used. In preliminary tests full charge identification for the reaction products up to Z = 11 have been obtained for products both crossing (ΔE-E technique) and stopping in the silicon detector, using a 21 MeV/u 20Ne beam at the LNS Superconducting Cyclotron in Catania. The quality of the obtained results clearly indicates that the digital signal processing approach is able to give excellent results in this application, too. [ABSTRACT FROM AUTHOR]

Mass and atomic-number identification (ID) of reaction products is a fundamental requirement of any nuclear reaction study. An effective particle-ID method is demonstrated, based on pulse shape analysis/discrimination (PSD) applied to large-area, single-element silicon detectors. This technique uses commercial electronic modules and achieves atomic number resolution rivaling that typically obtained with multi-element (ΔE - E) detector telescopes. The method is applied to the CHIMERA detector system without compromising its time-of-flight (TOF) resolution. In-beam tests of the PSD method have been performed with large-area, 300-μm thick CHIMERA silicon detectors, measuring particles from the 19F + 12C reaction at Tandem energies. Performance of a simple PSD set up is discussed, for front and rear particle injection. [ABSTRACT FROM AUTHOR]