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. The resolution at low energies is equivalent to that of our low ener. We use both ptype and ntype germanium and we use diffused, implanted, and barrier contacts to achieve this product variety. Performance of bare highpurity germanium detectors in liquid. 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.
The best choice of high purity germanium hpge detector detector efficiencye the detector efficiency in eq. The impact of the procedure and geometry on the detector performance was analyzed for eight detectors. Gamma background studies for the xenon experiment using a high purity germanium detector by jesse isaac angle may 2008 ci v. Characterization of a highpurity germanium detector for. Two types of geometry were used to fabricate hpge detectors. Youngman, evaluation of a high purity germanium detector body monitor, radiation protection dosimetry, volume 53, issue 14, 1 may 1994. These detectors are made of high purity germanium hpge ptype and n, or silicon lithium sili. Keywords gammaray spectrometry, solid angle, efficiency, radioactive measurements 1. High purity germanium hpge is the only radiation detection technology that provides sufficient information to accurately and reliably identify radionuclides from their passive gamma ray emissions. Abstractthe germanium detector array, gerda, will search for neutrinoless double beta decay in 76ge at the national gran sasso laboratory of the infn.
Performance of bare highpurity germanium detectors in. Some of the features that make silicon an excellent choice of material are the purity and the absence of dislocations, defects, and impurities. The detector energy resolution follows a characteristic. Amorphous germanium age contacts are used for blocking both electrons and holes. Segmented highpurity germanium detectors springerlink. The ultimate result of this analysis would be the deployment of this detector on an autonomous robot for sample collection and remote analysis. Otherwise, leakage current induced noise destroys the energy resolution of the detector. We present an initial evaluation of a mechanicallycooled, highpurity germanium doublesided strip detector as a potential gamma camera for smallanimal spect. A brief but very effective description on the basic formation. Characterization of mechanically cooled high purity germanium.
Index termsneutrinoless double beta decay, gerda, hpge detector, liquid argon. A highpurity germanium detector was modeled in mcnp6. Thus, the impurity concentration should be much reduced down to 1010. Fabrication process development for highpurity germanium radiation detectors with amorphous semiconductor contacts by quinn looker doctor of philosophy in nuclear engineering university of california, berkeley professor kai vetter, chair highpurity germanium hpge radiation detectors are well established as a valuable tool in. For applications where temperature stability of response is important near. The response of a highpurity germanium detector to xrays in the 815kev energy region has been investigated. Because germanium has relatively low band gap, these detectors must be cooled in order to reduce the thermal generation of charge carriers thus reverse leakage current to an acceptable level. What is high purity germanium detector hpge definition. The ultra high rate germanium uhrge project goal was to develop technology to operate high purity germanium hpge detectors with high throughput 85% in environments with incoming gammaxray event rates r106 s. High purity germanium detector array, proceedings of spie. Highpurity germanium detectors hpge detectors are the best solution for precise gamma and xray spectroscopy.
Digital timing algorithm for high purity germanium detectors. The wvalue and energy resolution dependencies on the xray energy have been studied. Hpge detectors excel in gammaray spectroscopy, offering excellent energy resolution with large detector sizes for high radiation detection efficiency. Characteristics of a highpurity germanium detector. Broad energy germanium detectors bege by canberra mirion technologies, inc. High purity germanium detector calibration at isolde gu. We measured full energy peak efficiency of high purity germanium detector which is important for gammaray spectrometry experiments. The high purity germanium spectroscopy detector is used in the detection and analysis of gammaray of environmental objects in nuclear energetics, products of industry and agriculture, medicine, etc. The core part of the detector consists of three encapsulated, 36fold segmented, highpurity germanium detectors hpge which are operated in a common cryostat. In gerda phasei, reprocessed enrichedge detectors, which were previously. Nats offers a complete range in high purity germanium detectors hpge. Performance of the ultrahigh rate germanium uhrge system. These crystals should not have a net electrically active impurity concentration greater than 10 l0 cm.
Fabrication process development for high purity germanium. Calculation of the peak efficiency of highpurity germanium. The detector consists of an ntype hpge crystal, 60mm in diameter and 90mm in length, with 36fold segmentation of the outer boron implanted contact. Physics the xenon dark matter experiment, deploi 4 at the gran sasso national laboratory in italy on march 2006, is a liquid noble gas detector designed to directly detect dark matter. Fabrication process development for highpurity germanium. Emerging role of highpurity germanium detectors for. 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 create an electronhole. 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. Use of a highpurity germanium semiconductor detector for. The following are five things you need to know about the use of hpge detector systems for homeland security applications in the field. 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. Bare highpurity germanium detectors enriched in 76ge will be submerged in liquid argon serving simultaneously as a shield against external radioactivity and as a cooling medium. The conventional coaxial germanium detector is often referred to as pure ge, hpge, intrinsic ge, or hyperpure ge.
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. Highpurity germanium hpge detectors can be produced from germanium material enriched in 76ge, which serves simultaneously as a source and as detector medium. Highpurity germanium strip detectors possible applications to sr studies. International journal of applied radiation and isotopes, vol. Signal modeling of highpurity ge detectors with a small read. Segmented planar high purity germanium detectors were developed. The response of highpurity germanium detectors to xrays. As a result, the fabrication process of small planar detectors at usd is discussed in great detail. In this case, however, it is advantageous to choose germanium rather than silicon as the detector material.
The electric and spectrometric characteristics of each individual segment and interactions between segments were investigated. The canberra broad energy ge bege detector covers the energy range of 3 kev to 3 mev like no other. Germanium76 is one of a handful of isotopes that can only decay through double beta decay of those isotopes, it is the second lightest and the most plentiful as a semiconductor, germanium is already commonly used in detectors using the same material for both source and detector allows for very simple detector construction. Detectors highpurity germanium detectors broad energy. Because the issue with leakage current only applies during operation, hpge. 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. This coaxial detector is available in an energy range of 40kev to 10 mev and offers high efficiency of radiation detection. A prototype high purity germanium detector array designed for use in the pulse height analysis mode as a discrete photon energy detector for medical imaging was fabricated and tested. Topsil hps float zone silicon for detectors has the following unique. This coaxial detector is available in an energy range of 40kev to. Sep 21, 2011 we present an initial evaluation of a mechanicallycooled, high purity germanium doublesided strip detector as a potential gamma camera for smallanimal spect. Calculation of the peak efficiency of highpurity germanium detectors. High purity germanium spectroscopy system north american.
High purity germanium detector array spie digital library. On the underground production of high purity germanium detectors. I have a question regarding gamma ray detector, the high purity germanium detector or aka hpge. Introduction silicon semiconductor detectors described in the previous chapter have depletion depths less than 1 mm, which are sufficient for charged particle spectroscopy or soft xray detection. A prototype high purity germanium detector for high. Ssbi can offer the optimum detector for a wide range of applications. High purity germanium detectors hpge are not just laboratory instruments anymore. The experiment uses high purity enriched ge crystal diodes as a beta decay source and particle detector. Using this model and the source term, the predicted response spectrum for each fallout composition was generated and compared using genie spectroscopy software in an attempt to find differentiating features between them. For photon spectroscopy in the energy region of hundred kev or several mev, much thicker semiconductor. This coaxial detector is available in an energy range of 10 kev to 10 mev. Semiconductor detectors also can be used in gammaray spectroscopy. This detector, based upon emerging silicon drift detector sdd technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium hpge detectors, without the need for liquid nitrogen.
Canberra models gc7020 old, from 1990, and gx6020 new, from. Segmentation of pn junction was performed by implantation of boron for the ntype ge and mechanical grooving of the li diffusion layer for the ptype ge. What is meant by the detection efficiency at specific gammaray energy. This summer student project involved the test and calibration of two high purity coaxial germanium gammaray detectors. This detector has been transported at room temperature, temperaturecycled many times to remove surface contamination, and remains an excellent device with a resolution of 4. The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. High purity germanium detectors hpge detectors are the best solution for precise gamma and xray spectroscopy. The purpose of this project was to develop a compact, modular multichannel xray detector with integrated electronics. The invention discloses a high purity germanium detector, which comprises a high purity germanium crystal, a first electrode and a second electrode, and a conductive protection ring, wherein the high purity germanium crystal has an intrinsicregion exposed surface. High purity germanium detector in gammaray spectrometry. High purity germanium hpge radiation detectors products. Calibration of hpge gammaray planar detector system for radioactivity standards tidatrut vichaidid 1, thongchai soodprasert1 and teerasak verapaspong2 abstract quantitative analysis of radioactive materials using efficiency calibration of gamma ray high purity germanium planar detector system has been studied. It can be made in large volumes to detect high energies and when operating at cryogenic temperatures it has.
Computer modeling of highpurity germanium detectors in. Thus, the impurity concentration should be much reduced down to. If silicon or germanium of normal semiconductor purity is employed, the maximum achievable depletion depth is a few mm even at bias voltages close to the breakdown level. High purity germanium hpge is widely used xray and. Calibration of hpge gammaray planar detector system for. We use both ptype and ntype germanium and we use diffused, implanted, and. Performance of bare highpurity germanium detectors in liquid argon for the gerda experiment m. Since the operation of hpgebased detectors is possible only at or below the liquid nitrogen temperature, their advantage is mainly the resolution, which matches the fano factor if appropriate cooled electronic readout is used. For applications where temperature stability of response is important near the cutoff, thermoelectrically cooled detectors are available. Learn more about ortecs high purity germanium radiation detectors hpge today. The present disclosure provides a high purity germanium hpge detector, comprising. High purity germanium detector calibration at isolde.
Ortec provides a comprehensive suite of hpge radiation detector solutions covering an extensive range of energies and for a variety of applications. The purpose of this research is to investigate the feasibility of using a high purity germanium double sided strip detector hpgedssd to image special nuclear material snm for use in the field of nuclear nonproliferation. Introduction gammaray spectrometry using high purity germanium hpge detectors has been an essential and principal corresponding author. A high purity berkeley germanium detector is in use at the argonne cp5 reactor. Introduction t he germanium detector array, gerda, will search for neutrinoless double beta decay 0 in 76ge 1 with the goal to investigate the nature of neutrinos and their mass. Characterization study of a broadenergy germanium detector at cjpl zeng zhi1 mi yuhao1 zeng ming1 ma hao1, yue qian1 cheng jianping1 li junli1 qiu rui1 zhang hui1 1 key laboratory of particle and radiation imaging ministry of education and department of engineering. Gamma background studies for the xenon experiment using a high purity germanium detector by jesse isaac angle may 2008 chair. Sep 16, 2011 a high purity germanium hpge detector is the ultimate instrument for energy spectrometry of gamma radiation. The germanium detector array, gerda, will search for neutrinoless double beta decay in 76ge at the national gran sasso laboratory of the infn.
To complete the gamma spectroscopy laboratory set caen sys includes in its offer a wide choice of high purity germanium detectors hpge. Other articles where germanium detector is discussed. For the nuclear hobbyist, an hpge opens a window into a fascinating realm of homeaccessible, lowintensity nuclear reactions that are obscured by background in other detectors lacking the superlative resolution. This relatively high value is of practical concern since highpurity germanium hpge is often the detector of choice for a and xray spectrometry. 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. A 128channel microstrip germanium detector system has been developed to efficiently detect comptonscattered xrays. 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. The performance of the germanium ge detector body monitor that has been recently installed at nrpb chilton is evaluated and compared with the perfo. Resolution and efficiency of high purity germanium detector. Energy linearity of highpurity germanium detectors in the. This does not come better than in topsil high purity silicon hps.
Detector fabrication and performance article pdf available in ieee transactions on nuclear science ns191. No abrupt variation of wis observed at the germanium k absorptionedge 11. High purity germanium hpge detectors remain the recognized gold standard for highresolution gammaray spectroscopy. A highpurity berkeley germanium detector is in use at the argonne cp5 reactor. The present disclosure provides a highpurity germanium hpge detector, comprising. Germanium detectors germanium short form catalog in pdf format j16 series detectors are highquality germanium photodiodes designed for the 800 to 1800nm wavelength range. Five things you need to know about using highpurity. Ortec offers a broad range of semiconductor photon detectors and options, as can be seen in the figure, covering energies in a range from a few hundred ev to 10mev gamma ray and upper. Results obtained as a function of the photon input rate, energy resolution, and techniques for correcting for pulse overlap at high count rates will be discussed. Digital timing algorithm for high purity germanium detectors knox andrew, university of massachusetts lowell, krzysztof starosta, david miller, constantin vaman, phillip voss, dirk weisshaar, michigan state universitynational superconduction cyclotron labratory the next generation of ray detector arrays will be composed of large volume high. Evaluation of a high purity germanium detector body. On the underground production of high purity germanium.
High purity germanium detectors are mostly used for gamma spectroscopy in nuclear physics, as well as xray spectroscopy. As a result, the fabrication process of small planar detectors at usd was discussed in great detail. The first gamma ray spectrometer is the one dimensional high purity germanium spectrometer. This work investigates the ability of a high purity germanium detector to perform postdetonation forensics on the debris from several types of nuclear weapons 24 hours after detonation. High purity germanium hpge radiation detectors are well established as a valuable tool in nuclear science, astrophysics, and nuclear security applications. Highpurity germanium for gamma detectors technical.
When photons interact with the material within the depleted volume of a detector, charge carriers holes and electrons are produced and are swept by the electric. We measured full energy peak efficiency of highpurity germanium detector which is important for gammaray spectrometry experiments. On the underground production of high purity germanium detectors mikael hult1, sergey belogurov2, allan caldwell3, josef janicsko3, vasiliy kornoukhov2,4, stefan schonert5 1 european commissionjoint research centreinstitute for reference materials and measurements ecjrcirmm, geel, belgium. The detector array is suspended in a liquid argon cryostat lined with copper and surrounded by an ultrapure water tank.
Why high purity germanium hpge radiation detection technology is superior to other detector technologies for isotope identification synopsis. The first triple cluster detector was successfully assembled for the next generation highresolution gammaray spectrometer. The detectors from the hdm and igex experiments were reprocessed and used in phase 1. With an atomic number of 32, germanium has a much higher photoelectric cross section than silicon atomic. High purity germanium detector repair conference osti. Germanium detectors are semiconductor diodes having a pin structure in which the intrinsic i region is sensitive to ionizing. It is 90 mm in diameter and 10 mm thick with two sets of 16 orthogonal strips that have a 4. Comparison of a high purity germanium gamma ray spectrometer.
As a result, gammaray spectrometers based on highpurity germanium detectors are emerging as a powerful tool for a range of planetary science applications. High purity germanium remains the material of choice for the detection of photons in the range of mev or higher, down to the hard xray range. Characterization of mechanically cooled high purity. Fabrication and characterization of highpurity germanium. Gamma background studies for the xenon experiment using a.