The chamber 150 also includes a wall portion that is disposed along a direction that is substantially perpendicular to {HEAD ~ the direction} of {TAIL ~ channel wall} 145 
The chamber 150 also includes a wall portion that is disposed along a direction that is substantially perpendicular to { HEAD ~ the direction } of { TAIL ~ channel wall } 145
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH