We claim the ornamental design for a portable detector, as shown and described.
FIG. 1 is a perspective view of an embodiment of a portable detector showing our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof; and
FIG. 7 is a bottom plan view thereof.
FIG. 8 is a perspective view of another embodiment of a portable detector showing our new design;
FIG. 9 is a front elevation view thereof;
FIG. 10 is a rear elevation view thereof;
FIG. 11 is a right side elevation view thereof;
FIG. 12 is a left side elevation view thereof;
FIG. 13 is a top plan view thereof; and,
FIG. 14 is a bottom plan view thereof.
The broken lines adjacent to the shaded areas depict boundaries of the claim and form no part of the claimed design. All other broken lines are directed to portions of the portable detector that form no part of the claimed design.