Halls personal opinion was that his hyperpure germanium detector an instrument. The first gamma ray spectrometer is the one dimensional high purity germanium spectrometer. The detector is coupled to an ortec model 572a spectroscopy amplifier and an. Both energy resolution and efficiency will be explored as a function of ray energy. The detector is equivalent to a pn junction having a thick layer of pure germanium at the position of the junction. Present high performance element germanium detector systems can give reasonable count rates with good resolution. With an atomic number of 32, germanium has a much higher photoelectric cross section than silicon atomic. Coaxial ge detector the conventional coaxial germanium detector is often referred to as pure ge, hpge, intrinsic ge, or hyperpure ge. Morsy, 2walid elmowafi, 1magda abd elwahab and 1nermin elanwar 1physics department, faculty of women for arts, science and education, ain shams university, heliopolis, cairo p.
A prototype high purity germanium detector for high. A new hyper pure germanium hpge detector system for invivo measurements has been installed in the low background laboratory at the centre for radiation, chemical and environmental hazards of public health england, based at chilton. High purity germanium detector calibration at isolde gu. Resolution and efficiency of high purity germanium detector. Moreover, the geometry of the sample on the detector is often chosen to. It uses large crystals of hyper pure germanium and is the first detector to use the concept of gammaray energy tracking. What is high purity germanium detector hpge definition. Detailed specifications are available for j16 series room temperature detectors, parallel output arrays, avalanche photodiodes and two color detectors. A cosmic muon veto system cmvs has been developed at ctbto headquarter to suppress muons induced background for a broad energy hyper pure germanium detector. Characterization of naturally occurring radioactive.
High purity germanium hpge detectors remain the recognized gold standard for highresolution gammaray spectroscopy. The clover detector consists of four closelypacked ntype hyper pure germanium. In comparison to silicon detectors, germanium is much more efficient than silicon for radiation detection due to its atomic number being much higher than silicon and due to lower average energy necessary to. Despite lasers being very popular and easy for the public to understand the importance of mr. High purity germanium hpge radiation detectors products. Abstract we present and evaluate a program for the semiempirical calculation of the fullenergy peak efficiency of a hyper pure germanium detector, by using the efficiency transfer method. Clover detectors setup for the study of beta decay. The conventional coaxial germanium detector is often referred to as pure ge, hpge, intrinsic ge, or hyperpure ge. This detector of extreme proportions is the largest wrulead we have built. Other articles where germanium detector is discussed.
Under reverse bias, an electric field extends across the intrinsic or depleted region. Two red lines on the left and right sides are the top and bottom of the detector. Silicon and germanium are available in higher purity grades than virtually any other elements. Hyper pure germanium hpge detector fabrication 4 hpge crystal were first developed in the mid 1970s. We use both ptype and ntype germanium and we use diffused, implanted, and barrier contacts to achieve this product variety. Hyper pure germanium detector hype was used to measure the radioactivity level. Semi conductor detectors medusa wiki the medusa institute. Helmer, gammaand xray spectrometry with semiconductor detectors, pp. The detector model 10180s with relative efficiency 9% and of 51 cm3 active volume, as shown in fig. The present disclosure provides a highpurity germanium hpge detector, comprising.
Several authors 111 have been treated the problem of the photopeak efficiencies determination and have given useful solutions. Germanium detector article about germanium detector by the. For applications where temperature stability of response is important near the cutoff, thermoelectrically cooled detectors are available. Thorlabs germanium based transimpedance amplified photodetectors feature a switchable gain setting housed in a compact, lowprofile package. Diode characteristics and spectral response to 7cs. A semiconductor detector in ionizing radiation detection physics is a device that uses a semiconductor usually silicon or germanium to measure the effect of incident charged particles or photons. What is the different between scintillation and hyper pure. Hyper pure germanium detectors hpge are outstanding devices for radioactivity spectroscopy.
Experimental setup the fullenergypeak efficiencies were determined for an ntype gmx ortec hpge detectors. Evaluation of a detector system for measurement of low. The sources of electrical noise that contribute to the width of peaks for germanium detectors is described in detail in numerous texts1, 2. Naa laboratories operate one or more hyper pure or intrinsic germanium hpge detectors at. This is the first 100 element detector manufactured commercially. The primary advantage of using clover detectors over conventional ge detectors is the increased photopeak sensitivity in addback mode for gamma energies above 1 mev. Encapsulated hpge detector titanium canister founding ice traces on mars subsurface.
Regardless of the superlative used, the detector is basically a cylinder of germanium with an ntype contact on the outer surface. Signal modeling of highpurity ge detectors with a small. Characterization of a highpurity germanium detector for. The use of hpge gamma rays detector for gross alpha and. Gretina is a new type of gammaray detector to study the structure and properties of atomic nuclei. The device and its electronic a hpge detector consists on a high purity germanium. The whole outside surface except the flat portion surrounding the hole forms the other contact. The fullenergy peak efficiency gammaray hpge detector for spherical sources is obtained by the use of direct analytical expressions. To determine the activity, the detector fullenergy peak photopeak efficiency is required. High purity germanium detector calibration at isolde. Germanium detectors are semiconductor diodes having a pin structure in which the intrinsic i region is sensitive to ionizing radiation, particularly x rays and gamma rays. The timeofflight tof technique, with a baf 2 detector placed close to the 252 cf source and a plastic detector located 37 cm from the source, just in front of the hpge.
A hyper pure germanium hpge system is tailored for measuring low activity samples. Highpurity germanium detectors hpge detectors are the best solution for precise gamma and xray spectroscopy. These early efforts were hindered by difficulties with detector fabrication, cumbersome electronics, and limited computing power, in addition to the need for a bulky liquid nitrogen dewar to achieve required operating temperatures rusinek. Hyperpure germanium detector article about hyperpure. The experiment uses high purity enriched ge crystal diodes as a beta decay source and particle detector. While it has a few of the properties of metals, in the pure form germanium is a brittle crystalline solid that instantly shatters when pressure or any other stress. Therefore, the count rate from background sources as building materials and cosmic rays is reduced by a castle of old lead placed around the detector. When photons interact with the material within the depleted volume of a. The excellent energy resolution that hpge detectors afford often makes them the detector of choice for applications as diverse as nuclear physics research, medical imaging, homeland security, and environmental monitoring. Silicon in particular can be had in large quantities at reasonable prices, at a purity that exceeds anything else achieved by the hand of man. Energy and efficiency calibrations for high purity.
Comparison of a high purity germanium gamma ray spectrometer. Gamma and xray spectrometry with semiconductor detectors. Gamma emissions are direct indicators of decay events. Ssbi can offer the optimum detector for a wide range of applications. Determination of the volume efficiency of hyper pure germanium hpge detector using ra 226 point source 1zeinab y. In this work, an ortec hyper pure germanium gamma ray spectrometer was used. Find out information about hyperpure germanium detector. Fepe calibration of a hpge detector using radioactive. Characterization of mechanically cooled high purity germanium. Liquid scintillation counter the quantulus 1220 scintillation counter manufactured by wallac, supported. Highprecision germanium detector is available eg germanium detector by jesse isaac angle may 2008 chair. Although there is little difference in detector performance between hpge and geli, the maintenance of geli is pretty inconvenient, which has made manufacturers stop producing them. Solid state detectors semiconductor based detectors materials and their properties energy bands and electronic structure charge transport and conductivity boundaries.
What is the shield of hyper pure germanium answers. Neutron interaction with germanium detector astrophysics. Semiconductor detectors find broad application for radiation protection, gamma and xray spectrometry, and as particle detectors. From june 11 to 14, 2018, nuctechs highpurity germanium detector with the independent intellectual property was exhibited at the symposium on radiation measurements and applications sorma, the first time for the detector to be exhibited outside china. A detailed study has been made of the interaction properties of neutrons and. Hyper pure germanium spectroscopy faster usecase n5 page 3 from 11 jm. Canberra models gc7020 old, from 1990, and gx6020 new, from. Projects nuclear science division nuclear science division. These detectors are sensitive to light in the nir spectral region from 800 nm to 1800 nm. It is clear from table 1 that for underground science with germanium detectors, it is mainly 68ge that may be a cause of concern. Using simple montecarlo integration and constructive solid geometry, we are able to calculate the effective solid angle for a wide range of hpge detector. Semiconductor detectors also can be used in gammaray spectroscopy.
Experimental measurement of fullenergy peak efficiency. Detector specification the detector under investigation is a commercial ptype bege detector model be6530 produced by canberra12 and it has been stored at cjpl for about 4 years. The performance of a radiation shielding system for a hyper pure germanium detector has been characterised for terrestrial radiation sources, cosmic muons, xray fluorescence and the compton scattering of source photons. The detector array is suspended in a liquid argon cryostat lined with copper and surrounded by an ultra pure water tank. It is closely related to target glint, or wander, an apparent displacement of the target from its mean position.
The device and its electronic a hpge detector consists on a high purity germanium crystal directly connected to its. Water sampling calibration in energy kev calibration in concentration ppm. Surface passivation of highpurity germanium gammaray. Highpurity germanium hpge detectors can be produced from germanium material enriched in 76ge, which serves simultaneously as a source and as detector medium.
The full energy peak efficiency of a hyper pure germanium hpge detector. Detectors of the radiation type based on pure germanium. Scintillation is a fluctuation in the amplitude of a target on a radar display. Montecarlo based background reduction and shielding. Nuctechs highpurity germanium detector is exhibited at. Germanium hpge detector detector efficiencye the detector efficiency in eq. Gretina consists of 28 highly segmented coaxial germanium crystals organized into 7 modules.
Determination of radium226 in rock samples by liquid. Several methods to reduce the background seen are quantified, including increasing the inner radius of the pb cave, and. Operation near liquid helium temperature of a gold. Determination of the volume efficiency of hyper pure. The system consists of five plastic scintillation plates operating in anticoincidence mode with the germanium detector. Learn more about ortecs high purity germanium radiation detectors hpge today. The borehole reaches to within in 2 cm of the backsurface of the pin device and forms one contact. This summer student project involved the test and calibration of two high purity coaxial germanium gammaray detectors. On the underground production of high purity germanium detectors. Regardless of the superlative used, the detector is basically a cylinder of germanium with an ntype contact on the outer surface, and a ptype contact on the surface of an axial well figure 11. The germanium ge detector is a counting detector and is the instrument that we will be using to count individual gamma emissions from samples.
Mar 22, 2018 this video shows a brief demonstration of fulcrum and gegi germanium gammaray detectors manufactured by phds co. Czt, the resolution of a given system can be degraded due to noise introduced to the detector output signal. Pdf the impact of high purity germanium gamma detection system koya4039 will be presented. After a user defines a geometry in the userinterface, the software then divides the active region of the source into many voxels and the detector surface into many pixels. In order to take benefit from their full capacities, one must connect them to state of the art signal processing spectroscopy amplifiers and acquisition boards. Its properties, hardware and software structure be. Physics the xenon dark matter experiment, deployed at the gran sasso national laboratory in italy on march 2006, is a liquid noble gas detector designed to directly detect dark matter. Ultra pure germanium detector with closedend coaxial contact geometry. In this paper, three distinctly different detector mechanicalcooler combinations were investigated.
In gammaray spectroscopy by hyper pure germanium detectors, one usually needs to know the photopeak efficiency for any specific source detector system. For operation as a detector it is backbiased in the sense of an ordinary diode and is a good insulator at liquid n 2 temperatures. The advantages of the intrinsic radiopurity and excellent spectroscopic performance 2 3 kev full width at half maximum resolution at qbb 2039 kev of hpge detectors have. Attempts to apply segmented germanium planar detectors to nuclear medicine imaging extend back at least forty years mccready et al. The detectors from the hdm and igex experiments were reprocessed and used in phase 1. Large volume detectors with small capacitance can be achieved with the coaxial. Then after cooling the detectors to 77 k gammaray emissions from radioisotopes are resolved resolution depletion depth vr versus ir characteristics and na nd of the germanium. Sources of noise examined include microphonics and simulated lowfrequency noise via input sinusoidal wave forms. A new digital filter has been investigated for removing lowfrequency periodic noise from the output signal of hyper pure germanium detectors hpge. Since we are only using one detector, we are missing most of the decays because they emit gammas in every direction. It is built from large crystals of hyper pure germanium and will be the first detector to use the recently developed concept of gammaray energy tracking. The trajectories of diffirent particles are labeled by color according to their charges. Energy and efficiency calibrations for high purity germanium gem30195 coaxial detector using k 0.
A schematic view of the detector configuration is shown in figure 1. Hyperpure germanium crystal, a sample of the element. Germanium detectors germanium short form catalog in pdf format j16 series detectors are highquality germanium photodiodes designed for the 800 to 1800nm wavelength range. Measuring the thickness of the dead layer of a ptype germanium detector is an issue of major importance since it determines the ducial mass of the detector. The detector type is high purity germanium, which is a semiconductor that must be temperature controlled with liquid nitrogen to 77 k due to excessive leakage current at higher temperatures 2.
The first involves fabrication of hyper pure germanium gamma ray detectors using standard surface treatment chemical etchings and containment in a suitable cryostat. Solid state detectors semiconductor based detectors. A particle detector which detects ionization produced by energetic charged particles in the depletion layer of a reversebiased pn junction in a semiconductor, usually a very pure single crystal of silicon or germanium. When photons interact with the material within the depleted volume of a detector. The efficiency characterization of germanium detectors at. Rad includes canberra detectors for protons, energetic ions, neutrons and gamma rays measurements on martian surface. The project has been strongly motivated by a special production of germanium detectors for the gerda experiment. A semiconductor detector in ionizing radiation detection physics is a device that uses a semiconductor usually silicon or germanium to measure the effect of incident charged particles or photons semiconductor detectors find broad application for radiation protection, gamma and xray spectrometry, and as particle detectors. With an atomic number of 32, germanium has a much higher photoelectric cross section than.
Improvement of spectral resolution in the presence of. Operation near liquid helium temperature of a goldbarrier hyperpure germanium detector for gammarays. The germanium detector assembly monitors radiation in an integrating sphere. Facts, pictures, stories about the element germanium in. Natural germanium is composed of 5 isotopes with relative natural abundances as given in table 1, which also gives the halflife of germanium radionuclides with halflife longer than 1 minute. Neutral particles are green, negative red, and positive blue. A variant of the lithiumdrifted germanium crystal which uses highpurity germanium, making it possible to store the detector at room temperature rather. Characterization of naturally occurring radioactive materials in libyan oil pipe scale using a germanium detector and monte carlo simulation author links open overlay panel a. The detector has high responsivity, good linearity, fast response times, and excellent longterm stability. Hpge detector fullenergy peak efficiency calculation for. High purity germanium detectors are mostly used for gamma spectroscopy in nuclear physics, as well as xray spectroscopy. A study of fast neutron interactions in highpurity germanium.
Nuctechs highpurity germanium detector is exhibited at sorma in the us. The dependence of the energy resolution on the shaping parameter will be investigated. In this case, however, it is advantageous to choose germanium rather than silicon as the detector material. Gamma and xray spectrometry with semiconductor detectors by. The calibration of hyper pure germanium detectors is required to calculate the activity of radioactive sources. Neutron interaction with germanium detector at diffirent energy scale. Assessment detector rad among 10 other scientific instruments on mars. However, the mca can be also connected to other type of detectors such as scintillators e. The highquality photodiode is designed for the 800 to 1800 nm wavelength range.
Naa laboratories operate one or more hyper pure or intrinsic germanium hpge detectors. Pdf high purity germanium koya4039 gamma detection system. Detector fabrication and performance article pdf available in ieee transactions on nuclear science ns191. To collect the charge liberated in a germanium detector a voltage must be applied.