AmChart logarithmic scale problem

HTML

<script src="http://www.amcharts.com/lib/amcharts.js"></script>
<script src="http://www.amcharts.com/lib/raphael.js"></script>
<div id="chartContainer" style="width: 640px; height: 400px;"></div>

JavaScript

var chartData = [
    {
    category: "Family History",
    maxRisk: 6,
    risk: 1,
    maxFill: "#eee9e9",
    catFill: "#FF00FF"},
{
    category: "Genetic",
    maxRisk: 0.08,
    risk: 1,
    maxFill: "#eee9e9",
    catFill: "#00FF00"}];

var chart = new AmCharts.AmSerialChart();
chart.dataProvider = chartData;
chart.categoryField = "category";

chart.startDuration = 5;
chart.marginTop = 15;
chart.marginLeft = 55;
chart.marginRight = 15;
chart.marginBottom = 80;

chart.angle = 30;
chart.depth3D = 15;
chart.decimalsSeparator = ".";


var catAxis = chart.categoryAxis;
catAxis.gridCount = chartData.length;

var balloon = chart.balloon;
//set properties
balloon.adjustBorderColor = false;
balloon.color = "#000000";
balloon.fillColor = "#FFFFFF";
balloon.borderColor = "#000000";
balloon.cornerRadius = 5;

var valAxis = new AmCharts.ValueAxis();
valAxis.logarithmic = true;
valAxis.baseValue = 1;
//valAxis.minimum = 1;
//valAxis.maximum = 6;



chart.addValueAxis(valAxis);

var graph = new AmCharts.AmGraph();
graph.valueField = "maxRisk"
graph.type = "column";
graph.lineAlpha = 0;
graph.fillAlphas = 0.2;
graph.balloonColor = "#FFFFFF";
graph.balloonText = "Maximum [[category]] Risk: [[value]]";
graph.fillColorsField = "maxFill";
graph.urlField = "url";
graph.labelText = "Maximum: [[value]]";

chart.addGraph(graph);

var graph2 = new AmCharts.AmGraph();
graph2.valueField = "risk"
graph2.type = "column";
graph2.lineAlpha = 0;
graph2.fillAlphas = 0.8;
graph2.balloonColor = "#FFFFFF";
graph2.balloonText = "Your [[category]] Risk: [[value]]";
graph2.fillColorsField = "catFill";
graph2.labelText = "[[value]]";

chart.addGraph(graph2);



chart.write('chartContainer');