How to Pack Particles Densely Using PSD

I want to generate high-density particle packing using a PSD (Particle Size Distribution).
However, when I create a model using PSD, the particles become loosely (sparse) packed.

How can I generate high-density particle packing?

Here is my program

#################################################################
from __future__ import print_function
import matplotlib
matplotlib.rc('axes', grid=True)
from yade import pack
import pylab
from yade import pack, plot, polyhedra_utils, geom
from yade import export, qt
import numpy as np
import os

# Particle sizes and cumulative probabilities
psdSizes = [0.000075, 0.000106, 0.00025, 0.000425, 0.00085, 0.002]
psdCumm = [0.001200, 0.006200, 0.795933, 0.999666, 0.999733, 1.0000]

# Scaling the particle sizes by a factor of 2
psdSizes_scaled = [size * 2 for size in psdSizes]

# Units: Mass (kg), Length (m)
frictangle = 45 / 180 * np.pi # Calculating 45 degrees in radians
density = 2400.0 # kg/m3
young = 3e7 # N/m2 Young's modulus

mat_sp = FrictMat(young=young, poisson=0.15, frictionAngle=frictangle, density=density)
O.materials.append(mat_sp)

sp = pack.SpherePack()
sp.makeCloud((0, 0, 0), (.06, .06, .02), psdSizes=psdSizes_scaled, psdCumm=psdCumm, periodic=True)

# Insert the packing into the simulation
sp.toSimulation(color=(0, 0, 1)) # Pure blue