diff --git a/grand/dataio/root_files.py b/grand/dataio/root_files.py
index 138e472d..e6f1bb44 100644
--- a/grand/dataio/root_files.py
+++ b/grand/dataio/root_files.py
@@ -12,6 +12,7 @@
 
 import numpy as np
 import ROOT
+import matplotlib.pyplot as plt
 
 import grand.dataio.root_trees as groot
 from grand.basis.traces_event import Handling3dTraces
@@ -192,6 +193,37 @@ def get_obj_handling3dtraces(self):
         o_tevent.info_shower += f" energy_primary={nrj:.1e} GeV"
         return o_tevent
 
+    def get_nb_traces_in_file(self):
+        nb_traces = 0
+        cur_idx = self.idx_event
+        for idx in range(self.get_nb_events()):
+            self.load_event_idx(idx)
+            nb_traces += self.du_count
+        self.load_event_idx(cur_idx)
+        return nb_traces
+
+    def plot_histo_vmax(self, nbins=20):
+        cur_idx = self.idx_event
+        a_vmax = np.zeros(self.get_nb_traces_in_file(), dtype=np.float32)
+        idx_t = 0
+        #for idx_e in range(self.get_nb_events()):
+        for idx_e in range(10):
+            self.load_event_idx(idx_e)
+            tr3d = self.get_obj_handling3dtraces()
+            max_norm = tr3d.get_max_norm()
+            a_vmax[idx_t : idx_t + self.du_count] = max_norm
+            idx_t += self.du_count
+            
+        _, bins = np.histogram(a_vmax, bins=nbins)
+        logbins = np.logspace(0,np.log10(bins[-1]),len(bins))  
+        plt.figure()
+        plt.title(f"{self.f_name}\nHistogram of max value for each traces")
+        plt.hist(a_vmax, bins=logbins)
+        #plt.xscale('log')
+        plt.yscale('log')
+        plt.grid()
+        self.load_event_idx(cur_idx)
+
 
 #
 # public function class
diff --git a/scripts/plot_grandlib_vmax_adc_events.py b/scripts/plot_grandlib_vmax_adc_events.py
new file mode 100644
index 00000000..d843cb7c
--- /dev/null
+++ b/scripts/plot_grandlib_vmax_adc_events.py
@@ -0,0 +1,51 @@
+"""
+Created on 16 avr. 2024
+
+@author: jcolley
+"""
+import sys
+
+
+import grand.dataio.root_trees as groot
+import numpy as np 
+import matplotlib.pyplot as plt
+
+
+pnf_event = sys.argv[1]
+s_evt = pnf_event.split("/")
+
+# Read only traces
+fevt = groot.TADC(pnf_event)
+# close doesn't exist ?
+#fevt.close()
+print(fevt.event_number)
+sys.exit()
+
+
+a_nb_tr = ak.num(traces, axis=1)
+nb_traces = ak.sum(a_nb_tr)
+print("nb traces: ",nb_traces)
+a_vmax = np.zeros(nb_traces, dtype=np.float32)
+nb_evt = ak.num(traces, axis=0)
+idx_t = 0
+for idx, nb_tr in zip(range(nb_evt),a_nb_tr) :
+    tr3d = ak.to_numpy(traces[idx])
+    max_norm = np.max(np.linalg.norm(tr3d, axis=1), axis=1)
+    a_vmax[idx_t : idx_t + nb_tr] = max_norm
+    idx_t += nb_tr
+print("end")
+
+_, bins = np.histogram(a_vmax, bins=20)
+logbins = np.logspace(0,np.log10(bins[-1]),len(bins))
+plt.rcParams["savefig.bbox"]='tight'
+plt.rcParams["savefig.pad_inches"]=0.2
+plt.title(f"Histogram of max value for {nb_traces} traces")
+plt.hist(a_vmax, bins=logbins)
+plt.xscale('log')
+plt.yscale('log')
+plt.xlabel(f"ADU\nDir: {s_evt[-2]}\nFile: {s_evt[-1]}")
+plt.ylabel("Number of trace in bin")
+plt.grid()
+plt.savefig(f'histo_grandlib_{nb_traces}_traces.png')
+
+#plt.show()
\ No newline at end of file
diff --git a/scripts/plot_uproot_vmax_adc_events.py b/scripts/plot_uproot_vmax_adc_events.py
new file mode 100644
index 00000000..15a16a63
--- /dev/null
+++ b/scripts/plot_uproot_vmax_adc_events.py
@@ -0,0 +1,64 @@
+"""
+Created on 16 avr. 2024
+
+@author: jcolley
+"""
+import sys
+
+import awkward as ak
+import uproot
+import numpy as np
+import matplotlib.pyplot as plt
+
+
+pnf_event = sys.argv[1]
+s_evt = pnf_event.split("/")
+
+# Read only traces
+fevt = uproot.open(pnf_event)
+traces = fevt["tadc"]["trace_ch"].array()
+fevt.close()
+
+# array of number of traces by event
+a_nb_tr = ak.num(traces, axis=1)
+# number of all traces in  files
+nb_traces = ak.sum(a_nb_tr)
+print("nb traces: ", nb_traces)
+a_vmax = np.zeros(nb_traces, dtype=np.float32)
+nb_evt = ak.num(traces, axis=0)
+idx_t = 0
+for idx, nb_tr in zip(range(nb_evt), a_nb_tr):
+    tr3d = ak.to_numpy(traces[idx])
+    max_norm = np.max(np.linalg.norm(tr3d, axis=1), axis=1)
+    a_vmax[idx_t : idx_t + nb_tr] = max_norm
+    idx_t += nb_tr
+print("end")
+
+idx_zero = np.where(a_vmax == 0.0)[0]
+print(len(idx_zero))
+idx_un = np.where(a_vmax == 1.0)[0]
+print(len(idx_un))
+
+_, bins = np.histogram(a_vmax, bins=20)
+logbins = np.logspace(-0.001, np.log10(bins[-1]), len(bins))
+plt.rcParams["savefig.bbox"] = "tight"
+plt.rcParams["savefig.pad_inches"] = 0.2
+plt.figure()
+plt.title(f"Histogram of max value for {nb_traces} traces")
+plt.hist(a_vmax, bins=logbins)
+plt.xscale("log")
+plt.yscale("log")
+plt.xlabel(f"ADU\nDir: {s_evt[-2]}\nFile: {s_evt[-1]}")
+plt.ylabel("Number of trace in bin")
+plt.grid()
+plt.savefig(f"histo_uproot_{nb_traces}_traces.png")
+
+plt.figure()
+plt.title(f"Histogram of max value for {nb_traces} traces")
+plt.hist(a_vmax, bins=50)
+plt.xlabel(f"ADU\nDir: {s_evt[-2]}\nFile: {s_evt[-1]}")
+plt.ylabel("Number of trace in bin")
+plt.yscale("log")
+plt.grid()
+plt.savefig(f"histo_noxlog_{nb_traces}_traces.png")
+# plt.show()