The Melexis Technologies MLX90614 Family Infrared Thermometer Sensor is a good option if you are looking for a high precision non-contact temperature measurement sensor. Both the IR sensitive thermopile detector chip and the signal conditioning ASSP are integrated in the same TO-39 can.
Two options for evaluation boards are available here: Eval Boards for MLX90614
Sensors.
Melexis’ application note, Soldering Techniques for TO39 IR Sensor Products can be downloaded via the link.
During soldering, if peak solder temperature is higher than 225°C, or if going through a wash, the IR window cannot get wet or over heated, hence the need for a cap. The cap or cover would need to be totally sealed.
For example, when using MLX90614ESF-AAA-000-TU, a ID=3/8” cap is recommended.
The TO-39 can would be placed manually. Melexis recommends that you use a spacer as well, such as one of the options found here: Parametric Spacer Search Results
AE10875-ND