diff --git a/script/Electric_field_loop.py b/script/Electric_field_loop.py
index da735a8..8fd1679 100644
--- a/script/Electric_field_loop.py
+++ b/script/Electric_field_loop.py
@@ -43,7 +43,7 @@ os.chdir("/sls/X11MA/data/X11MA/beamtime_december/")
 file_prefix = time.strftime("%y%m%d")
 ts=time.time();
 time_prefix = datetime.datetime.fromtimestamp(ts).strftime('%H:%M:%s')
-filename=open("data"+file_prefix++time_prefix+".txt","a")
+filename=open("data"+file_prefix+time_prefix+".txt","a")
 
 #for i in range(0,No_of_steps):
 #    B = -Max + 2*i*dB;