An apparatus includes a sample chamber constructed according to a design certified by the Department of Transportation for transporting fluids at a first pressure P1. A cylindrical sample compartment exists within the sample chamber. The sample compartment is designed to withstand the pressure P1. The cylindrical sample compartment has a cylindrical inner surface with a radius r and a height h. A hollow cylindrical sleeve is secured to the cylindrical inner surface of the sample compartment and has a wall of thickness t. The sample chamber is capable of transporting fluids at a second pressure P2. P2 is higher than P1.