tfer_W1.m

% TFER_W1   Evaluates the transfer function for a PMA in Case E.
% Author:   Timothy Sipkens, 2019-03-21
% 
% Inputs:
%   sp          Structure defining various setpoint parameters 
%               (e.g. m_star, V). Use 'get_setpoint' method to generate 
%               this structure.
%   m           Particle mass
%   d           Particle mobility diameter
%   z           Integer charge state
%   prop        Device properties (e.g. classifier length)
%
% Outputs:
%   Lambda      Transfer function
%   G0          Function mapping final to initial radial position
%=========================================================================%

function [Lambda, G0] = tfer_W1(sp, m, d, z, prop)

if prop.omega_hat ~= 1
    warning(['WARNING: omega_hat ~= 1! ', ...
        '<strong>tfer_W1</strong> output is likely inaccurate.'])
end

[tau, C0, ~, rs] = parse_inputs(sp, m, d, z, prop);
        % parse inputs for common parameters

%-- Estimate device parameter --------------------------------------------%
lam = 2 .* tau .* ([sp.alpha]' .^ 2 - ...
    [sp.beta]' .^ 2 ./ (rs .^ 4)) .* prop.L ./ prop.v_bar;


%-- Evaluate G0 and transfer function ------------------------------------%
G0 = @(r) 1 ./ ([sp.omega1]' .* sqrt(m)).*...
    sqrt((m .* [sp.omega1]' .^ 2 .* r .^ 2 - C0) .* exp(-lam) + C0);

ra = min(prop.r2, max(prop.r1, G0(prop.r1)));
rb = min(prop.r2, max(prop.r1, G0(prop.r2)));

Lambda = (1 ./ (2 .* prop.del)) .* (rb - ra);

end