Since being rediscovered three decades ago, scroll technology has been succ
essfully adapted to vacuum use. Several innovations have allowed scroll-typ
e pumps to produce vacuums lower than 10 mTorr; the pumps are used in many
applications requiring an inexpensive, dry, long-lived pump. In this articl
e, we detail the scroll design procedure, focusing on the trade offs betwee
n the need for sufficient vacuum and low manufacturing cost. As an illustra
tive example, we consider the design requirements for a high helium compres
sion scroll design for use in leak detectors. We also present guidelines fo
r proper pump operation, including the need for gas ballasting, high-water
operation, and proper pump isolation schemes. (C) 2001 American Vacuum Soci
ety.