Stop raycasting for close distance

Hello everyone, I have my raycast shooting code but I want it not to raycast to the collisions which is too close to player. I want it because I'm using Camera.main.ScreenPointToRay so it sometimes collides with itself, let me explain with some pics :

I mean when I look down it collides with itself and particles are being seen very ridiculusly, so is there anything I can do for not to Raycast too close ?

Here is my code :

     function Start(){
     
     hitParticles = gun.GetComponentInChildren(ParticleEmitter);
     if (hitParticles)
     
     }
 
 function Update(){
     var hit : RaycastHit;
     var ray = Camera.main.ScreenPointToRay (Vector3(Screen.width/2,Screen.height/2));
     
     if(Input.GetMouseButton(0)&& Time.time > nextFire){
     
     
     nextFire = Time.time + fireRate;
     
     if (Physics.Raycast(ray,hit,100)){
     
         Debug.DrawLine( transform.position, hit.point, Color.red);
     
           
                
                 if (hitParticles) {
             
         
                 hitParticles.transform.position = hit.point;
                 hitParticles.transform.rotation = Quaternion.LookRotation(hit.normal);
                 hitParticles.Emit();
                 
             }
     
     }
     }
 
 }