A method for adjusting a gain of a gamma detector comprises detecting gamma radiation using the detector, recording the detected radiation as count rates in channels, wherein the last channel accumulates all counts above the maximum recorded energy; comparing the last channel count rate (LCCR) to a threshold X and, if LCCR>X, decreasing the gain by a preset amount Y. If LCCR≤X, establishing a first estimate of a needed voltage HV1 using tool temperature and a temperature lookup table, and establishing a second estimate of a needed voltage HV2 using a backscatter peak value and a backscatter lookup table; comparing |HV1−HV2| to a threshold Z; if |HV1−HV2|<Z, adjusting the gain of the gamma detector by HV2 or, if |HV1−HV2|≥Z, adjusting the gain of the gamma detector by HV1.

The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

Embodiments are directed generally to an ionizing-radiation beamline monitoring system that includes a vacuum chamber structure with vacuum compatible flanges through which an incident ionizing-radiation beam enters the monitoring system. Embodiments further include at least one scintillator within the vacuum chamber structure that can be at least partially translated in the ionizing-radiation beam while oriented at an angle greater than 10 degrees to a normal of the incident ionizing-radiation beam, a machine vision camera coupled to a light-tight structure at atmospheric/ambient pressure that is attached to the vacuum chamber structure by a flange attached to a vacuum-tight viewport window with the camera and lens optical axis oriented at an angle of less than 80 degrees with respect to a normal of the scintillator, and at least one ultraviolet (“UV”) illumination source facing the scintillator in the ionizing-radiation beam for monitoring a scintillator stability comprising scintillator radiation damage.

Embodiments are directed generally to an ionizing-radiation beamline monitoring system that includes a vacuum chamber structure with vacuum compatible flanges through which an incident ionizing-radiation beam enters the monitoring system. Embodiments further include at least one scintillator within the vacuum chamber structure that can be at least partially translated in the ionizing-radiation beam while oriented at an angle greater than 10 degrees to a normal of the incident ionizing-radiation beam, a machine vision camera coupled to a light-tight structure at atmospheric/ambient pressure that is attached to the vacuum chamber structure by a flange attached to a vacuum-tight viewport window with the camera and lens optical axis oriented at an angle of less than 80 degrees with respect to a normal of the scintillator, and at least one ultraviolet (“UV”) illumination source facing the scintillator in the ionizing-radiation beam for monitoring a scintillator stability comprising scintillator radiation damage.

The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

A method is provided for determining the dose rate {dot over (H)} of nuclear radiation field, namely a gamma radiation field, with a radiation detection system (RDS), comprising a scintillator, a photodetector, an amplifier and a pulse measurement electronics. The pulse measurement electronics includes a sampling analog to digital converter, where the nuclear radiation deposes at least some of its energy in the scintillator, thereby producing excited states in the scintillation material, with the excited states decaying thereafter under emission of photons with a decay time τ. Photons are absorbed by the photodetector under emission of electrons, those electrons forming a current pulse, said current pulse being amplified so that the resulting current signal can be processed further in order to determine the charge of the pulse measured.

A method is provided for determining the dose rate {dot over (H)} of nuclear radiation field, namely a gamma radiation field, with a radiation detection system (RDS), comprising a scintillator, a photodetector, an amplifier and a pulse measurement electronics. The pulse measurement electronics includes a sampling analog to digital converter, where the nuclear radiation deposes at least some of its energy in the scintillator, thereby producing excited states in the scintillation material, with the excited states decaying thereafter under emission of photons with a decay time τ. Photons are absorbed by the photodetector under emission of electrons, those electrons forming a current pulse, said current pulse being amplified so that the resulting current signal can be processed further in order to determine the charge of the pulse measured.

A spectrometer for downhole applications can be calibrated without using radioactive sources. A spectrum of measured gamma ray counts can be received from a spectrometer in a calibration mode. A spectrum-to-window ratio can be used to determine a relationship between voltage level applied to a photoreceptor of the spectrometer and gain factors. A voltage level associated with a gain factor of one can be identified for use by the spectrometer in a non-calibration mode. The measured gamma ray counts and reference shapes for a plurality of radioactive elements can be used in a least squares fit process to determine an offset to apply to the spectrometer in the non-calibration mode.