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Since 2014, a new detector (New-Tupi) consisting of four plasticscintillators ($150 \times 75 \times 5 cm^3$) placed in pairs and located inNiteroi, Rio de Janeiro, Brazil, has been used for the search of transientsolar events and photomuons from gamma-ray bursts (GRBs). On September 15,2015, at 21:18:24 UT, the Swift Burst Alert Telescope (BAT) triggered andlocated GRB 150915A (trigger 655721). The GRB light curve shows a weak complexstructure of long duration $T_{90}=164.7 \pm 49.7 $ s, and a fluence in the15-150 keV band of $8.0 \pm 1.8 \times 10^{-7}erg/cm^2$. GRB 150915A wasfortuitously located in the field of view of the New-Tupi detector, and asearch for prompt emission in the GeV energy range is presented here. Theanalysis was made using the "scaler" or "single-particle" technique. TheNew-Tupi detector registered a counting rate excess peak of duration$T_{90}=(6.1\pm 0.6)$ s with a signal significance $(4.4\pm 0.5)\sigma$, (andnot $6.9\sigma$ as reported in the previous version). The signal is within theT90 duration of the Swift BAT GRB, with an estimated "excess" fluence of$F_S(E>0.1 GeV)=1.3 \pm 0.3 \times 10^{-6} erg/cm^2$. This value can beconsidered the lower limit of the gamma ray fluence in the GeV energy region.However, the Poisson probability of the event to be a background fluctuation is$5.0 \times 10^{-6}$ and it appears in the counting rate of the New-Tupidetector with an annual rate $\sim 76$. In addition, the signal has asignificance of only $2\sigma$ in the time profiles with a bin above 2 seconds.Thus we conclude that the event has a high probability to be backgroundfluctuation.

Prompt emission from GRB 150915A in the GeV energy range detected at ground by the New-Tupi detector: A review