public CIMColorModulationInfo ColorModulation {get; set;}

//Must be called on the MCT
//var pcsl = ...;
var def = pcsl.GetDefinition() as CIMPointCloudLayer;
//Get the ColorModulation off the renderer
var modulation = def.Renderer.ColorModulation;
if (modulation == null)
  modulation = new CIMColorModulationInfo();
//Set the minimum and maximum intensity as needed
modulation.MinValue = 0;
modulation.MaxValue = 100.0;
//apply back
def.Renderer.ColorModulation = modulation;
//Commit changes back to the CIM
pcsl.SetDefinition(def);