Cal. Pen. Code § 3700
When a court enters an order appointing a day upon which a judgment of death shall be executed upon an incarcerated person, the warden of the state prison to whom the incarcerated person has been delivered for execution or, if the incarcerated person is housed at the Central California Women's Facility, the warden of that facility, shall notify the Secretary of the Department of Corrections and Rehabilitation who shall then select and appoint three psychiatrists or licensed psychologists, all of whom must be from the medical staffs of the Department of Corrections and Rehabilitation to examine the incarcerated person under the judgment of death, and investigate the incarcerated person's competence to be executed. It is the duty of the psychiatrists or licensed psychologists so selected and appointed to examine the incarcerated person and investigate the incarcerated person's competence to be executed, and to report their opinions and conclusions in writing to the warden of the prison at which the execution is to take place, or, if the incarcerated person is housed there, the warden of the Central California Women's Facility, at least 20 days prior to the day appointed for the execution of the judgment of death upon the incarcerated person. Upon receipt, the warden shall serve a copy of the report to counsel for the incarcerated person, to the Attorney General, to the district attorney of the county in which the person was sentenced, and to the Governor.
Ca. Pen. Code § 3700