diff --git a/appletree/maps/_gas_gain.json b/appletree/maps/_gas_gain.json
new file mode 100644
index 00000000..bd113f7b
--- /dev/null
+++ b/appletree/maps/_gas_gain.json
@@ -0,0 +1 @@
+{"coordinate_lowers": [-70, -70], "coordinate_uppers": [70, 70], "coordinate_type": "regbin", "coordinate_name": ["x", "y"], "map": [[31.3, 31.3, 31.3, 31.3, 31.3], [31.3, 31.3, 31.3, 31.3, 31.3], [31.3, 31.3, 31.3, 31.3, 31.3], [31.3, 31.3, 31.3, 31.3, 31.3], [31.3, 31.3, 31.3, 31.3, 31.3]]}
\ No newline at end of file
diff --git a/appletree/parameters/er.json b/appletree/parameters/er.json
index 45f666b8..9e74f917 100644
--- a/appletree/parameters/er.json
+++ b/appletree/parameters/er.json
@@ -25,17 +25,6 @@
         "unit": "1",
         "doc": "Fano factor which describes the fluctuation of num of quanta"
     },
-    "gas_gain": {
-        "prior_type": "fixed",
-        "prior_args": {
-            "val": 31.3
-        },
-        "allowed_range": null,
-        "init_mean": null,
-        "init_std": null,
-        "unit": "PE/electron",
-        "doc": "Gas gain"
-    },
     "drift_velocity": {
         "prior_type": "fixed",
         "prior_args": {
diff --git a/appletree/parameters/nr_low.json b/appletree/parameters/nr_low.json
index f6219d75..f061a685 100644
--- a/appletree/parameters/nr_low.json
+++ b/appletree/parameters/nr_low.json
@@ -1,15 +1,4 @@
 {
-    "gas_gain": {
-        "prior_type": "fixed",
-        "prior_args": {
-            "val": 31.3
-        },
-        "allowed_range": null,
-        "init_mean": null,
-        "init_std": null,
-        "unit": "PE/electron",
-        "doc": "Gas gain"
-    },
     "drift_velocity": {
         "prior_type": "fixed",
         "prior_args": {
diff --git a/appletree/plugins/detector.py b/appletree/plugins/detector.py
index d8bf8766..f9dadefa 100644
--- a/appletree/plugins/detector.py
+++ b/appletree/plugins/detector.py
@@ -139,21 +139,24 @@ def simulate(self, key, parameters, num_electron, drift_survive_prob):
         return key, num_electron_drifted
 
 
+@takes_config(
+    Map(name="gas_gain", default="_gas_gain.json", help="Gas gain (x,y) dependence"),
+)
 @export
 class S2PE(Plugin):
-    depends_on = ["num_electron_drifted", "s2_correction_true"]
+    depends_on = ["num_electron_drifted", "s2_correction_true", "x", "y"]
     provides = ["num_s2_pe"]
     parameters = ("g2", "gas_gain")
 
     @partial(jit, static_argnums=(0,))
-    def simulate(self, key, parameters, num_electron_drifted, s2_correction_true):
-        extraction_eff = parameters["g2"] / parameters["gas_gain"]
-        g2_true = parameters["g2"] * s2_correction_true
-        gas_gain_true = g2_true / extraction_eff
+    def simulate(self, key, parameters, num_electron_drifted, s2_correction_true, x, y):
+        pos_true = jnp.stack([x, y]).T
+        gas_gain = self.gas_gain.apply((pos_true))
+        extraction_eff = parameters["g2"] * s2_correction_true / gas_gain
 
         key, num_electron_extracted = randgen.binomial(key, extraction_eff, num_electron_drifted)
 
-        mean_s2_pe = num_electron_extracted * gas_gain_true
+        mean_s2_pe = num_electron_extracted * gas_gain
         key, num_s2_pe = randgen.truncate_normal(key, mean_s2_pe, jnp.sqrt(mean_s2_pe), vmin=0)
 
         return key, num_s2_pe