Commit db168039 authored by Sara Ruiz Daza's avatar Sara Ruiz Daza
Browse files

adding the weak inversion slope factor as parameter

parent 0810e987

src/modules/CSADigitizer/CSADigitizerModule.cpp

+6 −2
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ CSADigitizerModule::CSADigitizerModule(Configuration& config, Messenger* messeng 
        config_.setDefault<double>("detector_capacitance", Units::get(100e-15, "C/V"));

        config_.setDefault<double>("amp_output_capacitance", Units::get(20e-15, "C/V"));

        config_.setDefault<double>("transconductance", Units::get(50e-6, "C/s/V"));

        config_.setDefault<double>("weak_inversion_slope_factor", 1.5);

        config_.setDefault<double>("temperature", 293.15);

    }
@@ -105,13 +106,15 @@ CSADigitizerModule::CSADigitizerModule(Configuration& config, Messenger* messeng 
        auto capacitance_feedback = config_.get<double>("feedback_capacitance");

        auto capacitance_output = config_.get<double>("amp_output_capacitance");

        auto gm = config_.get<double>("transconductance");

        auto n_wi = config_.get<double>("weak_inversion_slope_factor");

        auto boltzmann_kT = Units::get(8.6173333e-5, "eV/K") * config_.get<double>("temperature");



        // helper variables: transconductance and resistance in the feedback loop

        // weak inversion: gf = I/(n V_t) (e.g. Binkley "Tradeoff and Optimisation in Analog CMOS design")

        // n is the weak inversion slope factor (degradation of exponential MOS drain current compared to bipolar transistor

        // collector current) n_wi typically 1.5, for circuit described in  Kleczek 2016 JINST11 C12001: I->I_krumm/2

        auto transconductance_feedback = ikrum / (2.0 * 1.5 * boltzmann_kT);

        // collector current) and it is process specific

        //n_wi typically 1.5, for circuit described in  Kleczek 2016 JINST11 C12001: I->I_krumm/2

        auto transconductance_feedback = ikrum / (2.0 * n_wi * boltzmann_kT);

        auto resistance_feedback = 2. / transconductance_feedback; // feedback resistor

        auto tauF = resistance_feedback * capacitance_feedback;

        auto tauR = (capacitance_detector * capacitance_output) / (gm * capacitance_feedback);
@@ -127,6 +130,7 @@ CSADigitizerModule::CSADigitizerModule(Configuration& config, Messenger* messeng 
                   << ", gm = " << Units::display(gm, "C/s/V")

                   << ", tauF = " << Units::display(tauF, {"ns", "us", "ms", "s"})

                   << ", tauR = " << Units::display(tauR, {"ns", "us", "ms", "s"})

                   << ", weak_inversion_slope_factor = " << n_wi

                   << ", temperature = " << Units::display(config_.get<double>("temperature"), "K");

    } else if(model_ == DigitizerType::CUSTOM) {

        calculate_impulse_response_ =