CN205176286U - Anti - compton scatter detector - Google Patents

Abstract

The utility model discloses an anti - compton scatter detector, including the main detector that the sodium iodide material made, photomultiplier is connected to the lower extreme of main detector, and the nested synthetic supplementary detector of plastic scintillator preparation that gets into of main detector is the light guide material between main detector, the supplementary detector, and photomultiplier is connected to supplementary detector upper end, and supplementary detector lower extreme is the lead screen ring. The beneficial effects of the utility model are that: and then reduce the purpose that crude gamma -ray scattered photon ( compton effect ) background influences in the realization at utmost, and improve the accuracy of environment gamma -ray testing result on the spot, simplify the constitutional unit of detector, reduced the complete machine consumption.

Description

Anti-Compton scattering detector

Technical field

The utility model belongs to radiation detecting apparatus technical field, relates to a kind of anti-Compton scattering detector.

Background technology

" under high background condition low content radiological measuring " technology is subject to concern (H.Oeschger, 1975 of Chinese scholars always for a long time; KenichiNogami, 1978; The ó rssonP.1991; Zheng Renqi, 1985,1995; Li Deping, 1994; Huang Naiming, 2004; Deng).Numerous scholar has in all directions carried out extensive work from theory and method research to measuring system development and Application with regard to this problem.Traditional environment low-level radioactivity monitoring mode is " on-site sampling-lab analysis " (being also the major way of current domestic employing), not high (the Sha Lianmao of scene degree of analytical technology, 2011), poor in timeliness, use equipment mostly is large-sized analytic instrument in laboratory, is not easy to carry and analysis cost is higher.

Existing environmental activity on the spot gamma spectrum measuring system major part adopts the mode of multiple detector coupling measurement, object (P.P.Povinec, 1996 of realize reducing sample-out count, effectively extracting target species Radioactive information; A.Chernyaev, 2004; Etal).High purity germanium detector is widely used in the type radiological measuring system because it has the feature that energy resolution is good, detection efficiency is high, but because this type detector is higher therefore need mate corresponding refrigeration system to operating temperature requirements, this just determines HpGe gamma energy spectrometer complicated integral structure not Portable belt.Although the Detective-DX series portable nucleic discrimination system that and for example Ortec produces adopts electric refrigeration modes to simplify system, need the alternating current supply continued with stable refrigeration system, this refrigerant system configurations is complicated simultaneously, and system stability is not high.

Except high purity germanium detector, also select LaBr both at home and abroad ₃, other halogen scintillators such as SrBr as detector, the advantage of this quasi-instrument is that energy resolution is good, highly sensitive.But explorer portion cost is higher, be about the 7-8 of the cost of equivalent specifications NaI detector doubly, this makes the type detector be difficult to widespread use to a great extent.

The domestic patent research present situation about environment low-activity detection system on the spot mainly contains: " ocean original position Anticoincidence shield gamma energy spectrometer " (CN203502589U of the people such as the Cheong Kuoc Va of Oceanic Instruments & Meters Inst., Shandong Prov. Academy of Sciences, publication date: on March 26th, 2014), " the Low background gamma energy spectrometer for Marine Radioactivity is measured " (CN103217702A of the people such as Zhang Yingying, publication date: on July 24th, 2013), the journey of Tsing-Hua University builds equality people " a kind of combination screened room of Low background gamma ray spectrometer " (CN103675887A, publication date: on March 26th, 2014) etc.Above patent mainly concentrates on lab analysis and in-situ study field, ocean, and measuring system is larger, and the portable environment low-activity detection system be similar to herein have not been reported.

Be with array combination form in existing Multi probe combination detector, and the form of the nested combination of major-minor detector is comparatively rare, existing nested combination detector mainly with HpGe or lanthanum bromide semiconductor as main detector, the outer scintillator detector used is as auxiliary detector, because main detector working temperature in this combination (-188 DEG C ~-163 DEG C) requires comparatively harsh, the refrigeration of larger volume and power must be added (as electricity refrigeration, mechanical refrigeration, liquid nitrogen refrigerating etc.) device, so this type of design proposal mainly uses for lab analysis, not there is portability.

Summary of the invention

The purpose of this utility model is to provide a kind of anti-Compton scattering detector, significantly reduce the interference of natural ray, effectively eliminate the impact of natural radionuclide scattered photon, optimize existing measuring technique, realize the extraction of low-level radioactive nucleus prime information in high background, the main and auxiliary detector that helps all uses scintillator detector need not auxiliary refrigerating equipment, simplify the ingredient of low-level radiological measuring system to the full extent, achieve the miniaturization of instrument and equipment, cost degradation.

The technical scheme that the utility model adopts is, a kind of anti-Compton scattering detector, comprise the main detector that sodium iodide material is obtained, the lower end of main detector connects photomultiplier, main detector is nested enters the auxiliary detector that plastic scintillant makes synthesis, be light-guide material between main detector, auxiliary detector, auxiliary detector upper end connects photomultiplier, and auxiliary detector lower end is lead shield ring.

Further, main detector is cylindrical.

Further, the betal can in magnesium oxide reflection horizon is plated in main detector, the overall outer envelope of auxiliary detector.

The beneficial effects of the utility model are:

1. main detector uses sodium iodide crystal, auxiliary detector is plastic scintillant, the mode nested by well type combines, examination natural gamma ray all produces response on major-minor detector, realize not exporting of this signal by the mode of anticoincidence, and then realize the object reducing natural gamma ray scattering photon (Compton effect) background impact to the full extent.

2. the independent output signal of auxiliary detector is added on the background spectrum of anticoincidence output, the peak back of the body ratio of effective raising target species characteristic ray counting, reach the object improving detection accuracy, reduce minimum detectable activity whereby, improve the accuracy of environmental γ ray detection result on the spot.

3. combination detector of the present utility model is without the need to auxiliary refrigerating equipment, simplifies the structural unit of detector, reduces Overall Power Consumption, achieve the miniaturization of instrument and equipment, portability; Meanwhile, selected the mode that plastic scintillant and sodium iodide combine, comparatively existing high purity germanium detector significantly reduces cost.

4. the utility model will effectively improve existing low content radioactivity on the spot, real time monitoring level; Greatly enrich radiation environmental monitoring means.Meanwhile, save China's environs radiation monitoring engineering practice cost to the full extent, effectively promote the construction of China's nuclear radiation monitoring network.

Accompanying drawing explanation

Fig. 1 is the utility model anti-Compton scattering detector structural representation.

Fig. 2 is the energy spectrogram collected by the utility model detector.

In figure, 1. photomultiplier, 2. betal can, 3. auxiliary detector, 4. light-guide material, 5. lead shield ring, 6. main detector, 7. high-energy ray, 8. low energy ray.

Embodiment

The structure of anti-Compton scattering detector as shown in Figure 1, comprise the main detector 6 that sodium iodide material is obtained, the lower end of main detector 6 connects photomultiplier 1, main detector 6 is nested enters " well " type auxiliary detector 3 that plastic scintillant makes synthesis, Fig. 1 is the sectional view of detector, main detector 6 is in cylindrical embedding auxiliary detector 3, so auxiliary detector is well type, main detector 6, it is light-guide material 4 between auxiliary detector 3, auxiliary detector 3 upper end connects photomultiplier 1, auxiliary detector 3 lower end is lead shield ring 5, main detector 6, the betal can 2 in plating magnesium oxide reflection horizon in the overall outer envelope of auxiliary detector 3.

Extract from the natural radioactivity background that height counts to object element lower for counting be produced gamma-rays, devise anti-Compton scattering detector.The ray (high-energy ray 7) that the natural radionuclide that energy is higher produces can carry out energy deposition because Compton effect formation scattered photon returns on auxiliary detector 3 again after auxiliary detector 3 in main detector 6, such high-energy ray 7 will output signal simultaneously on main detector 6, auxiliary detector 3, by this signal shielding, the object reducing sample-out count can be namely achieved by the method for anticoincidence; And artificial radionuclide produce gamma-rays due to its energy lower (low energy ray 8), it only deposits in auxiliary detector 3, output pulse signal, although human nuclide counting is lower, but it has higher peak back of the body ratio compared to the sample-out count through anticoincidence process, namely relatively improve target species characteristic ray counting, improve sensitivity.

High low energy in the low energy ray mentioned in literary composition, high-energy ray is a relative concept, i.e. " natural ray energy is higher than artificial (target) ray energy ".

As shown in Figure 2: the power spectrum collected by this design, sample-out count can be reduced to original about 30%.

Claims (3)

1. an anti-Compton scattering detector, it is characterized in that, comprise the main detector (6) that sodium iodide material is obtained, the lower end of main detector (6) connects photomultiplier (1), main detector (6) is nested enters the auxiliary detector (3) that plastic scintillant makes synthesis, be light-guide material (4) between main detector (6), auxiliary detector (3), auxiliary detector (3) upper end connects photomultiplier (1), and auxiliary detector (3) lower end is lead shield ring (5).

2. a kind of anti-Compton scattering detector according to claim 1, is characterized in that, described main detector (6) is for cylindrical.

3. a kind of anti-Compton scattering detector according to claim 1, is characterized in that, the betal can (2) in plating magnesium oxide reflection horizon in described main detector (6), auxiliary detector (3) overall outer envelope.