Sorry for too late to modify the another code. The idea is draw some circle or semicircle in the sector using polar coordinate.
R = 10.5;
α = 0.05 π;(* 0< 2α < π *)
r = 0.5;
ϕ = 2 π*Sin[α];
draw2d[k_, θ0_] :=
With[{ρ0 = 2 k*r},
ParametricPlot[{ρ*Cos[θ], ρ*
Sin[θ]}, {ρ, 0, R}, {θ, 0,
2 π*Sin[α]},
MeshFunctions ->
Function[{x, y, ρ, θ},
Norm[ρ {Cos[θ],
Sin[θ]} - ρ0 {Cos[θ0], Sin[θ0]}] -
r], Mesh -> {{0}}, MeshShading -> {Red, None},
PlotPoints -> 80]];
Show[draw2d[0, 0],
Table[draw2d[k, θ0], {k, 1, Floor[R]}, {θ0,
Subdivide[0, ϕ, Round[ϕ/(2 ArcSin[1/(2 k)])]]}]]

And then use the isometry between sector and cone by this maps.
f[ρ_, θ_] = {ρ*Sin[α] Cos[θ/Sin[α]], ρ*Sin[α] Sin[θ/Sin[α]], ρ*Cos[α]};
After that we can lift the 2D to 3D.
R = 11.5;
α = 0.05 π;(*0<2α<π*)r = 0.5;
ϕ = 2 π*Sin[α];
f[ρ_, θ_] = {ρ*
Sin[α] Cos[θ/Sin[α]], ρ*
Sin[α] Sin[θ/Sin[α]], ρ*Cos[α]};
colors = {Pink, CMYKColor[4/100, 7/100, 19/100, 0]};
draw3d[k_, θ0_] :=
With[{ρ0 = 2 k*r},
ParametricPlot3D[
f[ρ, θ], {ρ, 0, R}, {θ, 0,
2 π*Sin[α]},
MeshFunctions ->
Function[{x, y, z, ρ, θ},
Norm[ρ {Cos[θ],
Sin[θ]} - ρ0 {Cos[θ0],
Sin[θ0]}] - r], Mesh -> {{0}},
MeshShading -> {colors[[Mod[k, 2, 1]]], None},
PlotPoints -> 80]];
Show[draw3d[0, 0],
Table[draw3d[k, θ0], {k, 1, Floor[R]}, {θ0,
Subdivide[0, ϕ, Round[ϕ/(2 ArcSin[1/(2 k)])]]}],
Boxed -> False, Axes -> False, ViewPoint -> {-2.39, 1.72, -1.64},
ViewVertical -> {-0.31, 0.18, -0.93}]
