diff --git a/electron.mac b/electron.mac
index 1ca1a78..f66ed5a 100644
--- a/electron.mac
+++ b/electron.mac
@@ -1,5 +1,5 @@
 # 多线程设置		
-/run/numberOfThreads 1
+/run/numberOfThreads 12
 
 # verbose		
 /control/verbose 2
diff --git a/src/PrimaryGeneratorAction.cpp b/src/PrimaryGeneratorAction.cpp
index f032be7..431143f 100644
--- a/src/PrimaryGeneratorAction.cpp
+++ b/src/PrimaryGeneratorAction.cpp
@@ -12,7 +12,6 @@
 
 G4double M = 931.5;
 G4double C1, C2, C3, C4, sum;
-std::ifstream modelFile("assets/model.txt");
 
 PrimaryGeneratorAction::PrimaryGeneratorAction() {
     G4ParticleDefinition* ion = DefineParticle();
@@ -29,6 +28,7 @@ PrimaryGeneratorAction::~PrimaryGeneratorAction() { delete fParticleGun; }
 G4ParticleDefinition* PrimaryGeneratorAction::DefineParticle() {
     G4double Z, A;
     std::string tmp, line, name;
+    std::ifstream modelFile("assets/model.txt");
 
     while (std::getline(modelFile, line)) {
         std::stringstream ss(line);