Tektronix part number 152-0140-01 is a 10 mA ±10% tunnel diode with a maximum capacitance of 8 pF. It is also known by part number SMTD995.
It is used in the 547 units with serial numbers 11890 and up.
According to Craig Sawyers' Diode Reference, it is used in the RM546, RM547, RM585, R544, R556, R7912, S-51, S-52, TU-5, 067-0572-00, 067-0572-01, 067-0681-00, 1S1, 1S2, 1502, 21A, 22A, 3T5, 3T6, 475/R, 475A/R, 475M, 544, 546, 547, 556, 581A, 585A, 7B52, 7B53N, 7B70, 7B71, 7D10, 7D11, 7T11, and 7T11A.
Note: There is a 152-0140-00 that is a different diode in a different package.