diff --git a/Cosmic_dustbox/Dp.py b/Cosmic_dustbox/Dp.py
new file mode 100644
index 0000000000000000000000000000000000000000..9bdefc047b19900d8601ba6b6726cc3d5137a8e2
--- /dev/null
+++ b/Cosmic_dustbox/Dp.py
@@ -0,0 +1,58 @@
+import astropy.units as _u
+import numpy as _numpy
+import warnings as _warnings
+import os as _os
+from scipy.interpolate import interp1d
+from scipy import integrate
+import sys
+Path = _os.path.dirname(_os.path.dirname(_os.path.realpath(__file__))) + \
+                 '//Solver//'  
+sys.path.insert(0, Path)
+import sdist as sd
+import GrainSpecies as gs
+###############################################################################
+###############################################################################
+
+
+class Dp(object):
+    
+    def __init__(self,en):
+        self.en = en
+       return
+   
+    
+    def Sigma_abs_E(en):
+        sizes = _np.logspace(self.sizeMin, self.sizeMax, \
+                             num = 10000)        
+
+        
+        def func1(sizes):
+            if issubclass(self.__class__, sd.SizeDist):
+                dist_gr = self.__class__(Sizes).sdist_gr
+                dist_sil = self.__class__(Sizes).sdist_sil            
+            return dist_gr , dist_sil 
+                        
+        def func2(Sizes):
+            sigma_cr = gs.SpGraphite.Sigma_abs(en,sizes)[0]
+            sigma_ sl = gs.SpAsil.Sigma_abs(en,sizes)[0]            
+           return sigma_cr, sigma_sl
+
+        f1_gr = interp1d(sizes, func1(sizes)[0], kind='linear')
+        f2_sl = interp1d(sizes, func1(sizes)[1], kind='linear')
+         
+        f3_gr = interp1d(sizes, func2(sizes)[0], kind='linear')
+        f4_sl = interp1d(sizes, func2(sizes)[1], kind='linear')
+        
+        Integ1 =integrate.quad(f1_gr(Sizes)* f3_gr(Sizes),self.sizeMin, \
+                               self.sizeMax)
+        Integ2 = integrate.quad(f1_gr(Sizes), self.sizeMin,self.sizeMax)
+
+        Integ3 =integrate.quad(f2_sl(Sizes)* f4_sl(Sizes),self.sizeMin, \
+                               self.sizeMax)
+        Integ4 = integrate.quad(f2_sl(Sizes), self.sizeMin,self.sizeMax)
+
+        sigma_abs_1 = Integ1/Integ2
+        sigma_abs_2 = Integ3/Integ4
+        sigma_abs_E = sigma_abs_1 + sigma_abs_2 
+        
+        return sigma_abs_E
\ No newline at end of file