The apparatus may include a fixture for supporting the sensor and holding {TAIL ~ the sensor} in {HEAD ~ the substantially fixed position} 
The apparatus may include a fixture for supporting the sensor and holding { TAIL ~ the sensor } in { HEAD ~ the substantially fixed position }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD