A simple test to figure out what the material parameters do:

Use Technical proposal benchmark as reference:

Default material is written down in this file:
tkgeometry/config/stdinclude/PixelMaterials.cfg

M Si 0 0 0 0.3 mm L ;

pt 	1000
Real 	2.30948
Ideal 	0.53651
Loss 	4.3 

d 	1000
Real 	0.00601
Ideal 	0.00241
Loss 	2.5 

z0 	1000
Real 	0.00696
Ideal 	0.00273
Loss 	2.5 

Changing the following:
M Si 0 0 0 3 mm L ;

pt 	1000
Real 	4.00824
Ideal 	0.53651
Loss 	7.5 


We changed the mass of the modules components (mass of module components ) by doubling it, and we repeated the exercise by leaving the mass of the components as it was and increasing the thickness (sensor thickness) of the sensor in order to get the same increase in mass.

  Real
  1 GeV	 
  
  Sensor thickness              Mass of module components     
  		        				
	C	I		C	I	
  pT	2.4663  3.80623         3.06497 4.7186
  d	0.00651	0.00850		0.00776	0.01019	
  z0	0.00747	0.01399	        0.00871	0.01685	
      
  Ideal    
  1 GeV	   	                TDR				
	C	I		C	I	
  pT	0.55644 0.086291        0.55644 0.86291
  d	0.00255	0.00268		0.00255	0.00268	
  z0	0.00277	0.00288	        0.00277	0.00288	 
  
 It is more convenient to use a thicker sensor with respect to using heavier material.