Nuclear magnetic resonance (NMR) probes nuclear spins, while electron spin resonance (ESR) probes electron spins through transitions between Zeeman-split energy levels in a magnetic field. Relaxation constants $T_1$, $T_2$, and $T_2^*$ are key parameters in pulsed ESR measurements and spin dynamics [1]. Conventionally, these relaxation constants are measured using the same microwave (MW) antenna that excites the electron-spin transitions, limiting spatially localized detection. Our group has already measured continuous-wave ESR with an electron probe inside the transmission electron microscope (TEM) [2]. Here, we aim to expand our technique to measure the relaxation constants with the electron probe positioned close to the sample. For this, we use a custom-made setup, including a TEM sample holder [3]. Inside the microscope, the electron spins are polarized using the objective lens field ($B_0 \approx 170 \ \mathrm{mT}$). For the measurement of relaxation constants, we plan to use standard sequences of π 2 and π pulses, in order to obtain spin echo and related signals [4]. This method could enable spatially resolved ESR relaxation measurements inside an electron microscope, opening new possibilities for nanoscale studies of magnetic and quantum materials.