Shrouds

XL designs shrouds with one or many thermal zones based on test article(s) size and heat load, or customer test parameters. Shroud gas (or liquid) flow is analyzed and the piping size and placement engineered to meet required thermal ramp rates and temperature uniformity. Shroud sections, piping and headers are always designed to facilitate installation and, if required, removal / replacement for shroud service or chamber maintenance reasons.

Click to download a TCU calculator to estimate how many CFM, and therefore how many TCUs you will need for your GN2 shroud.

Shrouds are constructed with D-tube on sheet, batwing extrusions, chevrons, or floor extrusions depending on customer requirements and the shroud application. For example, XL floor extrusion results in a smooth man-rated floor with thermal performance that meets the thermal requirements and the chevron extrusion is used in front of cryo pumps to increase pumping speed.

Shrouds can be designed for flooded LN2 (liquid nitrogen), or thermally controlled GN2 (gaseous nitrogen), or both in a switchable LN2 / GN2 configuration.

Helium shrouds are designed for gaseous helium (GHe) and operate at temperatures of 20K (-256°C), or less, up to 425K (+150°C). XL has constructed shrouds that are "double piped" with separate gas flows to accommodate dual purpose nitrogen and helium applications.

Shrouds are fully designed, fabricated and tested in-house. All shrouds are cold-shocked, pressure tested and leak checked after fabrication, and then cleaned and prepared for painting. We typically apply AKZO-Nobel 463-3-8 Cat-a-lac black paint with emissivity >0.9 @ 20°C followed by an atmospheric bake at 200ºF for 3 hours. Other paints are available depending on customer specification.

Helium shrouds go through the same detailed design and rigorous testing process.

	Batwing Shrouds Optical density & optimum thermal conductivity
	Chevron Shrouds Thermal conductivity & Cryo pump or cold panel access
	Floor Shrouds Thermal conductivity in a mechanically sound man-rated structure
	D-tube on Sheet Thermal conductivity with AL sheet &1/2" to 1" D-tube

Rigorous quality control and testing ensures shrouds that exceed performance requirements, at the factory, at acceptance and for years after.