prep).

In FRB search mode, the 4.0 degrees FWHP of the primary beam is tiled in the E-W direction by 352 elliptical, coherent, tied-array beams (called ‘fan-beams’, each 46$\arcsec$ wide), spaced 41$\arcsec$ apart and overlapping at very close to their half power points at 843 MHz. In the N-S direction the resolution of the fan-beams is the same as that of the primary beam ($\approx2.8$ degrees). The fan-beams are numbered from 1 to 352 running from East to West across the primary beam, with fan-beam 177 directly centred on boresight. The sensitivity of the telescope to bursts can be estimated using the radiometer equation:

$$S_\mathrm{min} = \beta \, \frac {(\mathrm{S/N_\mathrm{min}}) \, T_\mathrm{sys}} {G \, {\sqrt{\Delta\nu \, W \, N_\mathrm{p}}}}$$

![image](Fig3.pdf){width="5.0"}

where ${S_\mathrm{min}}$ is the minimum detectable flux for a threshold signal-to-noise $\mathrm{S/N_{min}}$, $\beta$ is the digitisation factor, $\Delta\nu$ is the bandwidth in Hz, ${N_\mathrm{p}}$ is the number of polarisations (${N_\mathrm{p}}=1$ for UTMOST as it is right circularly polarised only), $W$ is the pulse width in ms, ${T_\mathrm{sys}}$ is the system temperatures in K respectively, and $G$ is the system gain in K Jy$^{-1}$. We define S/N as the ratio of the sum of the on-pulse flux to the product of 