Update README.md

README.md

@@ -5,6 +5,8 @@ A geiger counter application for the Flipper Zero
 
 You need a **geiger counter** board to run this application. This board can be used : https://aliexpress.com/item/1005004074447209.html
 
+**Note :** this board uses a **J305** geiger tube. According this [website](https://www.rhelectronics.store/j305-glassy-geiger-muller-tube-nuclear-radiation-sensor) gamma conversion factor is **0.0081** for this tube. This value has been declared in the header of the source file so you can change it easily if needed.
+
 The geiger counter board can be powered with +5V power pin of the **Flipper Zero** 
 
 Output pin for measure on arduino cannot be used on the **Flipper Zero** because output voltage is too low. You can use jack out port instead. This port must be connected on **A7** GPIO :
@@ -34,9 +36,7 @@ If you don't want to build this application, just simply copy **flipper_geiger.f
 
 Ambient radioactivity :
 
-<img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flipper2.png" width=25% height=25%>
-<img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flippe8.png" width=25% height=25%>
-<img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flipper9.png" width=25% height=25%>
+<img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flipper2.png" width=25% height=25%> <img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flipper8.png" width=25% height=25%> <img src="https://github.com/nmrr/flipperzero-geigercounter/blob/main/img/flipper9.png" width=25% height=25%>
 
 Measure of uranium ore piece inside a lead container :
 
@@ -73,4 +73,4 @@ All previous measures in a row (the scale of the graph is automatically adjusted
   * Schematic was added
 
 * 2023-01-08
-  * Initial release
+  * Initial release