Breakthrough in pulse-shape based particle identification with silicon detectors

Recent results of CHIMERA activity

“…Identification threshold as lower as 1-2 MeV/nucleon have been reported [5]. In CHIMERA the experimental conditions were almost different with respect to Ref.…”

“…In CHIMERA the experimental conditions were almost different with respect to Ref. [5]: The Time of Flight Technique(TOF), used for mass identification, the large surface silicon detectors of moderately high resistivity already adopted ( to reduce detector bias) suggested to employ the pulse shape methods by using "CHIMERA standard" n-type planar detectors operating in DIRECT mode. After some studies, it was demonstrated that a reasonable low identification threshold as low as 4.5 MeV/nucleon for light ions was possible by adopting an appropriate rise time measurement of the silicon charge signal [6].…”

Charge and current-sensitive preamplifiers for pulse shape discrimination techniques with silicon detectors

“…This method proposed more than forty years ago [1] was recently investigated in detail in relation with the design of a 4π silicon ball [2,3,4,5]. Moreover potentially improved capabilities have been also discussed using homogeneously doped n-TD silicon detector [6,7] or PSD-time of flight coupling [8]. In all the recent studies PSD was obtained by using conventional charge-sensitive preamplifiers and by injecting particles or ions into the rear-side (n-side) of totally depleted detectors.…”

A single-chip telescope for heavy-ion identification

“…2). In order to get better particle identification from PSA, all silicon detectors were mounted with the ohmic side facing the target so that particles enter the detector from the low field face [13,14]. The silicon detectors, with an active area of 20 mm × 20 mm, are made of neutron transmutation doped (nTD) silicon having a resistivity of about 3 kΩ cm.…”

“…A key feature of FAZIA is the Pulse Shape Analysis (PSA) of detector signals. PSA is employed to identify fragments stopped in the first silicon [13][14][15], thus lowering the identification thresholds with respect to the standard ΔE-E technique, while at the same time avoiding the technical complications associated with gas detectors. The second silicon detector (or the combination of the two silicon detectors) and the CsI(Tl) constitute a ΔE-E telescope for identifing the most energetic LCP's and IMF's.…”