How do I (if possible) convert this raycast into a spherecast?

Unity Engine
1 
        Ray ray = new Ray(RayOrigin.transform.position, RayOrigin.transform.forward);
        RaycastHit hit = new RaycastHit();

        if (Input.GetMouseButtonDown(0) && Physics.Raycast (ray, out hit, 20f) && hit.collider.gameObject.CompareTag("Pickable"))
        {
            currRBcons = hit.rigidbody;
            currRBcons.GetComponent<Rigidbody>().constraints = RigidbodyConstraints.FreezePositionX | RigidbodyConstraints.FreezePositionY | RigidbodyConstraints.FreezePositionZ | RigidbodyConstraints.FreezeRotationX | RigidbodyConstraints.FreezeRotationY | RigidbodyConstraints.FreezeRotationZ;
        }
        if (Input.GetMouseButtonUp(0))
        {
            currRBcons.GetComponent<Rigidbody>().constraints = RigidbodyConstraints.None;
            currRBcons = null;
        }

I need my hit to be a bit wider and more generous in the radius. Thus I need a spherecast. Is it possible to convert this into a spherecast, if so how? I found Unity’s api to be lacking on the topic.

2 
Vector3 spherecenter=RayOrigin.transform.position;
float sphereradius=1f;
RaycastHit hit=new RaycastHit();

if (Input.GetMouseButtonDown(0) && Physics.SphereCast(spherecenter, sphereradius, RayOrigin.transform.forward, out hit, 20f, Physics.AllLayrers) && hit.collider.gameObject.CompareTag("Piclable")) {
    //do what you want
}