The recess for insertion of the cartridge in the first part being distant from the desk top prevents {TAIL ~ dust} and dirt to enter the housing and impairing the sensitive measurement of {HEAD ~ the sample} 
The recess for insertion of the cartridge in the first part being distant from the desk top prevents { TAIL ~ dust } and dirt to enter the housing and impairing the sensitive measurement of { HEAD ~ the sample }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD