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