Lucene: Indexing DateTime from Sitecore and querying date ranges

The title should be self explanatory. I need to index some sitecore items that represent some entities that are valid to the public between certain dates. The sitecore fields are date time fields looking like this.

I needed a solution for indexing these values in a way that i can do range queries on them. I used the UnixTimeStamp for converting the DateTime field in a UnixTimeStamp field.

public static string ConvertToUnixTimeStamp(DateTime value)
    {
      var date = new DateTime(1970, 1, 1, 0, 0, 0, value.Kind);
      var unixTimestamp = Convert.ToInt64((value - date).TotalSeconds);
      return unixTimestamp.ToString(CultureInfo.InvariantCulture);
    }

Decoding UnixTimeStamp to DateTime :

public static DateTime ConvertToDateTime(double unixTimeStamp)
    {
      DateTime dtDateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0);
      dtDateTime = dtDateTime.AddSeconds(unixTimeStamp).ToLocalTime();
      return dtDateTime;
    }

The fields would then be indexed as numbers and i could filter the results using a TermRangeQuery on the index like this:

TermRangeQuery trq = new TermRangeQuery(dateFieldName, UnixTimeStampConverter.ConvertToUnixTimeStamp(startDateTime), UnixTimeStampConverter.ConvertToUnixTimeStamp(endDateTime), true, true);

I think this solution is quite elegant and easy to use.