diff --git a/src/config.json b/src/config.json
index 080de22..82f4daf 100644
--- a/src/config.json
+++ b/src/config.json
@@ -1,6 +1,6 @@
 {
   "simulation": {
-    "num_walker": 20,
+    "num_walker": 20000,
     "seed": null
   },
   "molecule": {
@@ -10,7 +10,10 @@
   "correlation_times": {
     "distribution": "DeltaDistribution",
     "tau": {
-      "list": [1e2, 1e0]
+      "start": 1e-3,
+      "stop": 1e0,
+      "steps": 1,
+      "is_log": true
     }
   },
   "motion": {
@@ -34,7 +37,7 @@
   },
   "stimulated_echo": {
     "t_evo": {
-      "start": 2e-6,
+      "start": 10e-6,
       "stop": 100e-6,
       "steps": 98
     },
diff --git a/src/rwsims/sims.py b/src/rwsims/sims.py
index c486872..75083db 100644
--- a/src/rwsims/sims.py
+++ b/src/rwsims/sims.py
@@ -68,16 +68,18 @@ def run_ste_sim(config_file: str):
             ax5.semilogx(t_mix, ss/ss[0, :], '.-')
 
             for k in range(num_variables):
-                p0 = [0.5, 0, p.dist.variables.get('tau', 1), 1]
+                p0 = [0.5, 0, dist_values.get('tau', 1), 1]
 
                 p_final = []
                 p_final1 = []
                 for k, t_evo_k in enumerate(p.ste.t_evo):
+
                     try:
                         res = curve_fit(ste, t_mix, cc[:, k], p0=p0, bounds=([0, 0, 0, 0], [np.inf, 1, np.inf, 1]))
                         p_final.append(res[0].tolist())
                     except RuntimeError:
                         p_final.append([np.nan, np.nan, np.nan, np.nan])
+
                     try:
                         res2 = curve_fit(ste, t_mix, ss[:, k], p0=p0, bounds=([0, 0, 0, 0], [np.inf, 1, np.inf, 1]))
                         p_final1.append(res2[0].tolist())