If there is, it's in Senate Rules. I'm making a cursory review of them now.
http://rules.senate.gov/senaterules/menu.htm <- See XXIV and later
http://www.senate.gov/artandhistory/history/common/briefing/Committees.htm
Thanks. Jackbill's post at #133 provides some good info as well.
"4. Whenever upon such roll call it shall be ascertained that a quorum is not present, a majority of the Senators present may direct the Sergeant at Arms to request, and, when necessary, to compel the attendance of the absent Senators, which order shall be determined without debate; and pending its execution, and until a quorum shall be present, no debate nor motion, except to adjourn, or to recess pursuant to a previous order entered by unanimous consent, shall be in order."