On determining dead layer and detector thicknesses for a position-sensitive silicon detector

Abstract

In this work, two particular properties of the position-sensitive, thick silicon detectors (known as the "E" detectors) in the High Resolution Array (HiRA) are investigated: the thickness of the dead layer on the front of the detector, and the overall thickness of the detector itself. The dead layer thickness for each E detector in HiRA is extracted using a measurement of alpha particles emitted from a 212 Pb pin source placed close to the detector surface. This procedure also allows for energy calibrations of the E detectors, which are otherwise inaccessible for alpha source calibration as each one is sandwiched between two other detectors. The E detector thickness is obtained from a combination of elastically scattered protons and an energy-loss calculation method. Results from these analyses agree with values provided by the manufacturer.

Non-linearity effects on the light-output calibration of light charged particles in CsI(Tl) scintillator crystals

“…If the incident particle is completely stopped in the CsI detection stage, the correlation of the energy deposited in the first detection stage (usually indicated as ∆E) and its residual energy measured by the corresponding CsI can be used to identify the mass and charge of the incident particle (the ∆E-E identification technique). An example is shown in Figure 3 we have considered an equivalent silicon dead layer of 0.6 µm, as obtained from a previous dedicated investigation [27]. DSSSD electronics linearity has been verified by sending a series of calibrated pulses to the preamplifier of each strip.…”

“…Silicon energy calibrations have been carefully performed for each front and back strip by using 4 peaks of a 232 U α-source, spanning an effective energy range from 5.41 MeV to 8.58 MeV. To correct for the energy loss by the α-particles in the thin aluminum layer on the front side of the silicon, we have considered an equivalent silicon dead layer of 0.6 µm, as obtained from a previous dedicated investigation [27]. DSSSD electronics linearity has been verified by sending a series of calibrated pulses to the preamplifier of each strip.…”

“…A proper implementation of this technique relies on a precise knowledge of the energy deposited in the DSSSD and of its thickness. For this reason, silicon thickness values provided by the manufacturer, and ranging from 1460 µm to 1537 µm for all the telescopes in the array, have been benchmarked with a dedicated study [27]. However, this technique is limited only to the low or middle end of the CsI dynamic range.…”

“…For this experiment, one HiRA10 telescope without the DSSSD was placed at 24 degrees with respect to the beam line in a vacuum chamber. Additionally, a standard HiRA telescope (with 4 cm CsI crystals) without the DSSSDs, for which the light response has been previously tested at low energy [27] with an analogous setup, was placed symmetrically at −24 deg with respect to the beam line to serve as the reference for the HiRA10 test. A copper collimator with 4 circular holes centered at the 4 crystals with diameters of 1/8 in (0.317 cm) and 1/2 in (1.27 cm) for the 2 inner and the 2 outer crystals was placed in front of each HiRA telescope.…”

The Emission Order of Hydrogen Isotopes via Correlation Functions in 30 MeV/u Ar+Au Reactions

“…The SSDs were calibrated by combining the precise pulser generator and the 239 Pu α source. The thicknesses of the mylar foil (≈ 4µm) and the dead layer (≈ 0.6µm [53]) of SSD detector are corrected. After the SSDs with well-defined thickness were calibrated, the energy deposit in CsI(Tl) units could be calculated using the program LISE++ [54] and then calibrated through the ∆E 2 − E CsI band for each isotope.…”