diff --git a/cal_tools/cal_tools/enums.py b/cal_tools/cal_tools/enums.py
index a516dee2f55dbd8ece632c00f523d58a80b2f578..27ce86511b8ca208543be2aff5719b39affae331 100644
--- a/cal_tools/cal_tools/enums.py
+++ b/cal_tools/cal_tools/enums.py
@@ -49,3 +49,11 @@ class SnowResolution(Enum):
     NONE = "none"
     INTERPOLATE = "interpolate"
 
+
+class AgipdGainMode(Enum):
+    """Encoding added to distinguish between adaptive and fixed gain"""
+
+    ADAPTIVE_GAIN = 0  # adaptive is default (if gain mode missing in slow data)
+    FIXED_HIGH_GAIN = 1  # non-zero means fixed gain
+    FIXED_MEDIUM_GAIN = 2
+    FIXED_LOW_GAIN = 3