How to Disable browser back button after logout?

Masterpage view Code
----------------------

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class Admin_MasterPage : System.Web.UI.MasterPage
{
  SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constring"].ConnectionString);
  SqlCommand cmd;
  SqlDataReader dr;

  protected void Page_Load(object sender, EventArgs e)
  {
  Response.Cache.SetCacheability(HttpCacheability.NoCache);
  Response.Cache.SetExpires(DateTime.Now.AddSeconds(-1));
  Response.Cache.SetNoStore();
  Response.Buffer = true;
  Response.ExpiresAbsolute = DateTime.Now.AddDays(-1d);
  Response.Expires = -1500;
  Response.CacheControl = "";

  if (Session["username"] == null)
  {
  Response.Redirect("Login.aspx");
  }
 
  }
}

Hi Challa, Good Noon. Pls try this code Y