Drift control in an analytical gamma ray spectrometer

Claim 1

IN A MULTI-CHANNEL PULSE HEIGHT ANALYZER FOR ANALYZING THE GAMMA RAY SPECTRUM OF A NEUTRON BOMBARDED SAMPLE ELEMENT, INCLUDING A GAMMA RAY DETECTOR COUPLED TO SAID SAMPLE ELEMENT AND TO A PHOTOMULTIPLIER PROVIDED WITH A HIGH VOLTAGE SUPPLY, SAID PHOTOMULTIPLIER PROVIDED COUPLIED TO A CATHODE FOLLOWER, PREAMPLIFIER, LINEAR AMPLIFIER, ANALOG TO DIGITAL CONVERTER, ADDRESS CURRENT GENERATOR, FERRITE CORE MEMORY, AND A COMPUTER, THE IMPROVEMENT COMPRISING MEANS FOR AUTOMATICALLY AND CONTINUOUSLY ADJUSTING THE OVERALL DRIFT OF SAID ANALYZEWR DUE TO FLUCTUATIONS IN LINE VOLTAGE, HIGH VOLTAGE SUPPLY, AND PHOTOMULTIPLIER AND AMPLIFIER GAIN, SAID MEANS COMPRISING A FIRST SOURCE OF RADIOACTIVE REFERENCE PULSES COUPLED TO SAID GAMMA RAY DETECTOR FOR PROVIDING A FIRST REFERENCE PHOTOPEAK IN ONE OF THE LOWER CHANNELS OF SAID ANALYZER, A SECOND SOURCE OF RADIOACTIVE REFERENCE PULSES COUPLED TO SAID GAMMA RAY DETECTOR FOR PROVIDING A SECOIND REFERENCE PHOTOPEAK IN ONE OF THE UPPER CHANNELS OF SAID ANALYZER, FIRST MEANS COUPLED TO SAID FERRITE CORE MEMORY FOR MONITORING SAID ONE LOWER CHANNEL AND EACH CHANNEL ABOVE AND BELOW SAID ONE LOWER CHANNEL OF ANY DRIFT WHICH MAY OCCUR IN THESE LOWER CHANNELS, MEANS COUPLED TO SAID FIRST MONITORING MEANS AND RESPONSIVE TO ANY DRIFT UPWARD OR DOWNWARD OF SAID FIRST REFERENCE PHOTOPEAK IN SAID LOWER CHANNELS FOR AUTOMATICALLY CHANGING