Redirect or Open New Tab on LinkButton Click using Response.Redirect in ASP.Net

I used variety of code to redirect to new page in response.redirect using link button in vb.net but still not worked. Kindly give me some suggestions to solve my issue.

While using the Highlighted Code its redirecting with in the Page but i need to redirect to another page or new tab.

Response.Redirect("rep_woamend_wohistory.aspx?pamendno=" & amno & "&pwono=" & wono & "&pamend=SUPPLY")

<td align="left" class="tabletd" valign="top">
    <%--<asp:LinkButton ID="lnkament" Font-Bold="true" Visible="false" CssClass="blink" OnClientClick="targetMeBlank()" runat="server">AMENDMENT</asp:LinkButton>--%>
    <asp:LinkButton ID="lnkament" Font-Bold="true" Visible="false" CssClass="blink" target="_blank" runat="server">AMENDMENT</asp:LinkButton>
</td>

<script type="text/javascript">
    function targetMeBlank() {
        document.forms[0].target = "_blank";
    }    
</script>

    Protected Sub lnkament_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lnkament.Click
        Dim wono, sno, sno1, amno, str As String
        Dim anchor As New HtmlAnchor()
        Dim dt As DataTable
        wono = ddlWono.Text
        sno = ddlSono.Text
        sno1 = ddlwo1.Text
        str = ""
        dt = rep.amentdet(wono, sno, sno1)
        amno = dt.Rows(0)(0).ToString()
        'Response.Redirect("Rpt_so_wohistory.aspx?paramwono=" & wono & "&paramsno=" & sno & "")
        'Response.Redirect("rep_woamend_wohistory.aspx?pamendno=" & amno & "&pwono=" & wono & "&pamend=SUPPLY")
        'Response.Write("<script type='text/javascript'>window.open('rep_woamend_wohistory.aspx?pamendno=" & amno & "&pwono=" & wono & "&pamend=SUPPLY');</script>");

        Response.Write("<script>")
        Response.Write("window.open('rep_woamend_wohistory.aspx?pamendno=" & amno & "&pwono=" & wono & "&pamend=SUPPLY,'_blank')")
        Response.Write("</script>")        
    End Sub