Geotek Company Introduction:

Geotek, a British company, is the designer and manufacturer of the world's best-selling core equipment MSCL (Multi Sensor Core Logger Core Comprehensive Testing System, also known as Multi Parameter Core Scanner). Almost every laboratory engaged in core research work in the world (scientific research, engineering exploration, oil drilling, etc.) has installed MSCL, with over 220 users. MSCL has very stable, reliable, and durable performance, suitable for both laboratory and field use. It has been widely used in core libraries, geological key laboratories, temporary field laboratories, offshore survey ships, deep-sea drilling ships, and engineering ships around the world. Geotek is the most commonly used core analysis equipment by scientists. Wherever there are rock cores on Earth, there are Geotek products.

If a core is worth taking, it's worth logging. ...岩芯宝贵，数据无价。

Core Natural Gamma Measurement System

MSCL-NG

The MSCL-NG Core Natural Gamma Measurement System is one of the 10 MSCLs in the MSCL (Multi Sensor Core Logger Core Comprehensive Testing System, also known as Multi Parameter Core Scanner) series produced by GEOTEK in the UK (see product list above). It can measure complete rock cores and cut open rock cores, and is applied to seabed sediment column samples, lake sediment column samples, rock cores, etc.

MSCL-NG Core Natural Gamma Measurement System

Background:

Gamma rays are electromagnetic radiation emitted by the nuclei of unstable elements (radioactive isotopes) during the decay process. The long-lived radioactive isotopes in nature that can emit large amounts of gamma rays are: 40K with a half-life of 1.3 × 109 years, 238U with a half-life of 4.5 × 109 years, and 232Th with a half-life of 1.4 × 1010 years. K. U and Th are the most primitive known radioactive isotopes, both capable of emitting their own characteristic energies. Minerals containing K, U, and Th elements, such as clay minerals, are natural sources of gamma ray radiation.

Measurement principle:

The natural gamma sensor system consists of at least two, typically three 3 "x 3" sodium iodide (thallium) detectors placed in 6-inch diameter lead shielded tubes. Each sensor's sodium iodide (thallium) crystal is connected to a photomultiplier tube and a multi-channel processor MCA. Gamma rays entering the sensor strike the sodium iodide (thallium) crystal, generating a light pulse that enters the photomultiplier tube and produces a small current. Finally, a pulse voltage is output, and the peak height of the voltage corresponds to the energy of the gamma rays, which is recorded by one of the 1024 channels in the multi-channel processor MCA. The multi-channel processor collects gamma ray energy ranging from 0-3MeV.

The entire natural gamma measurement system is controlled by standard Geotek MSCL software, which can perform spectral measurements of all 1024 channels (energy range 0-3Mev) or simple total radiation counting measurements. Users can control the sampling position, sampling interval, and sampling counting time through the software to obtain high-resolution data. By calibrating the energy of the detector through a reference source, each detector can collect completely standard and stable spectral data through long-term measurement. If the user has suitable standard rock cores (known concentrations of K, U, and Th), the data obtained in spectral mode can be used by the user to estimate the relative content of elements such as K, U, and Th using third-party software. The user can also convert the total gamma radiation count to API industrial standard units based on their own standards.

Application:
Natural gamma measurement has three main uses:

(1) Correlation between rock cores

(2) Estimation of clay mineral/shale mineral content

(3) Estimation of K, U, and Th element abundances

The correlation between rock cores and the estimation of clay/shale mineral content can be evaluated through gamma radiation total count data. The analysis of K, U, and Th element abundance content is more complex, requiring the acquisition of spectral data and long-term sampling for estimation.

Natural Gamma Ray - Selection of Core Size and Shielding.

In the natural gamma ray measurement system, the rock core works by installing a central shielding cover with three detectors. The size of the shielding cover should be very close to the size of the rock core to achieve good shielding effect. Therefore, users need to provide the diameter of the rock core to be measured (including the size of the casing end cap). If multiple sizes of rock cores need to be measured, a suitable shielding cover should be purchased for each size.

Attention: The maximum measurable core diameter for natural gamma is 130mm. For exposed rock cores, a core tray is required, which can be made of ordinary PVC pipes.