This efficiency is always reduced by charge carriers trapping that results from crystal defects and the poor charge URL List 1|]# transport properties of charge carriers. For example, grain boundaries that are generated during crystal growth can seriously trap charge carriers [4]. It has been shown that spatial non-uniformity of semiconductor materials will cause a loss of Inhibitors,Modulators,Libraries energy resolution [5,6]. In addition, the mean drift length of electrons is typically of the order 1 cm while this length of holes is much lower than that of electrons with values around 0.1 cm under typical electric fields of 1,000 V/cm. With poor charge collection, the charge signal induced on the electrode is reduced, which Inhibitors,Modulators,Libraries is more pronounced for events that occur further away from the collecting electrode.
Inhibitors,Modulators,Libraries This is how the position-dependent signal variation is produced.Figure 2 shows two typical spectra obtained Inhibitors,Modulators,Libraries with a CdZnTe planar detector when irradiated from anode and cathode side, respectively. Inhibitors,Modulators,Libraries The anode-irradiating spectrum has no peak because most of the holes are trapped due to a long drift distance to the cathode. However, the peak can be clearly resolved on the cathode-irradiating spectrum. Since the amplitude of the induced charge signal depends on the depth of interaction (DOI), the cathode-irradiating spectrum still shows a tailing.Figure 2.A typical 241Am spectrum obtained with 4 �� 4 �� 2 mm3 CZT detector, which is irradiated from the cathode side (dashed line) and anode side (solid line).
The photopeak can be resolved if gamma rays are irradiated from the cathode side but …2.1.
Inhibitors,Modulators,Libraries Shockley-Ramo TheoryAs already stated, the charge carriers that are generated by ��-photon energy deposit drift Inhibitors,Modulators,Libraries towards the corresponding electrodes. Shockley and Cilengitide Ramo proposed a method in 1940s to calculate the induced charge by introducing a concept of ��weighting potential�� [8�C10]. The charge variance (��QL) that is achieved by a moving charge q from interaction position xi to xf and induced on the electrode (L), can be calculated according to Equation (1):��QL=��xixfqE0?dx=?q[��0(xf)?��0(xi)].(1)where xi to xf is the initial and final position of q, and E0 and 0 correspond to the weighting electric field and weighting potential respectively.
Weighting potential (electric field) is defined as the potential Inhibitors,Modulators,Libraries (electric field) that would exist in the detector Dacomitinib when the collecting electrode is biased at unit potential and all other electrodes are held grounded.
It does not really exist inside the detector Sorafenib VEGFR-2 but is only for calculation convenience. Note that the induced charge is independent of the applied bias voltage on the electrodes. That voltage only determines the trajectories of charge carriers.2.2. Static Charge Analysis and Capacitance Coupling MethodAnother approach to calculate the output charge on the electrode, called Dovitinib cost ��static charge analysis and capacitance coupling method��, was introduced by Lingren and Butler [11].