The phrase "a narrow gap in" is correct and usable in written English.
It can be used to describe a small opening or space within something, often in a physical or metaphorical context.
Example: "The hikers found a narrow gap in the rocks that led to a hidden cave."
Alternatives: "a small opening in" or "a tight space in".
An hour or so later, we reached Nemto and, passing through a narrow gap in the breakers, crossed the lagoon and ran up on the jungle-backed beach.
The measure had received initial support from the Clinton administration, notably from Attorney General Janet Reno, who said it would close a narrow gap in existing law.
…two hollow semicircular electrodes, called dees, mounted back to back, separated by a narrow gap, in an evacuated chamber between the poles of a magnet.
There was a large, incomplete portrait of a woman hanging from one wall, with its lower half descending through a narrow gap in the floor.
This work describes the design and testing of an ultrasonic reactor suitable for processes which require agitation within a narrow gap in a tank geometry.
Standing at the column between them, looking down through a narrow gap in the translucent screen, you can make out a line of rusting steel squares set into the ground at regular intervals.
A narrow-gap in-vacuum undulator has been proposed to be installed in one of the ALS straight sections.
Nationally, while Labour is still ahead, the Conservatives have been able to point to a narrowing gap in recent months.
Still, buoyed this week by a narrowing gap in one poll and an unexpected $600,000 from the National Republican Senatorial Committee, Mr. Franks said he believed that a race that once looked unwinnable had inched into the might-be column.
TechCrunch has comScores latest for the two sites, showing a narrower gap in the US and a virtual tie on a global level.
Our sensitivity analysis further suggested that lower attendance rates would result in a narrower gap in benefits between mass screening and stepwise strategies using routine data, which supports the use of routine data as prestratification tools.
