Avoid back button after logout in asp.net application

protected void LinkLogout_Click(object sender, EventArgs e)

 {

     try

         {

                Session.Abandon();

                FormsAuthentication.SignOut();

                Response.Cache.SetCacheability(HttpCacheability.NoCache);

                Response.Buffer = true;

                Response.ExpiresAbsolute = DateTime.Now.AddDays(-1d);

                Response.Expires = -1000;

                Response.CacheControl = "no-cache";

                Response.Redirect("login.aspx", true);

          }

        catch (Exception ex)

         {

            Response.Write(ex.Message);

          }

}