## 4 Discussion
For this reason, active area increment yielded higher signal amplification results and a high signal gain per mm\({}^{2}\) increase in active area in our study. [PERSON] [6] similarly highlighted active area to be directly correlated to photodiode sensitivity towards radiation; this likewise implies a proportionate signal build up in case of active area increment. The LED radiation signal was amplified by increasing the chip number because connecting multiple photodiodes in parallel can enhance photodiode effective active area and sensitivity [6]. However, during the active area-based amplification mode, the highest signal per mm\({}^{2}\) increase in the active area was observed in the course of visible light detection, because LEDs feasibly detect wavelengths that are similar to those they emit [15]. Therefore, active area increment-based signal amplifications were most effective during visible light detection. This finding further implies that the LED's low signal set-back, during light detection, could be offset by increasing the effective sensitive area: Hence, LEDs could substitute photodiodes during light detection applications, due to their low-cost and flexibility when compared to photodiodes. Whereas [PERSON] [6] applied transimpedance amplifiers to amplify low photodiode radiation-induced signals, our study executes electronic signal amplification with an amplifier board. Nevertheless, the board was presented with low signal amplification percentages throughout the tested X-ray parameter variations. Amplifier board settings could be adjusted to higher gains, but this was coupled with higher dark currents. These amplifier board pre-existent dark currents would ultimately obstruct precision in the measurement of net radiation-induced currents/signal amplifications. Amplified signals should additionally be precise and have low standard deviations because precise signals ensure accurate dosimetric calibrations. Herein, we examined amplified signal precision while using the coefficient of variation (CoV) tool, which is the percentage of the standard deviation (\(\sigma\)) to mean (\(\mu\)) ratio, i.e., CoV = \(\sigma\)/\(\mu\)x\(\times\)100%. Amplifier board signals had a 0.687% (9.424%-8.737%) higher coefficient of variation than the chip number-based signal amplifications; this could be as a result of amplifier board dark currents that might have hindered precise signal measurement. Additionally, the amplifier board's maximum usable output voltage was \(\pm\)4 V, which could imply a limited operational headroom. As a consequence, whilst adjusting the potentiometers to achieve low dark currents, the amplifier board easily got saturated to an output voltage of \(\sim\)4.24 V.  
Variation in the temperature surrounding the LED chips could lead to changes in the LED emission spectrum and emitted wavelengths: LED efficacy as a luminary reduces upon an increase in temperature [26]. The semiconductor material that is used for LED fabrication dictates LED bandgap energy and, ultimately, the energy of the emitted light photons [27]. This bandgap energy (\(E_{g}\)) is directly proportional to the speed of light-C and inversely proportional to emitted photon wavelength-\(\lambda\) with Plank's constant-\(h\) as the constant of proportionality, i.e., \(E_{g}=hC/\lambda\). An increase in temperature would reduce E\({}_{g}\) because E\({}_{g}\) is the energy difference between valence and conduction bands [2], thus an increase in the emitted photon wavelength. Therefore, data collection from our experimentswas executed in a radiology suite with room temperature being maintained at 24 \({}^{\circ}\)C. This testing condition minimized the signal-temperature dependence that could affect the sensibility of the LEDs implemented for diagnostic X-ray radiation detection herein. Although the efficiency of LEDs is a function of LED PN junction temperature, InGaN-based LEDs (for instance, blue, green, white) are less ambient-temperature dependent [28].