A kind of radioiodine sampler
Technical field
The utility model belongs to the radioactivity survey technology, is specifically related to a kind of radioiodine sampler.
Background technology
Sampling monitoring to radioactivity iodine-131 in the environment is to estimate the important evidence of environmental radio activity level, and present various radiation monitoring stations all use the radioiodine sampler to collect airborne gaseous iodine sample.The radioiodine sampler generally comprises one and is used for adsorbing by gas production stream
131The active carbon adsorption box of I, the absorption box connects admission line and outlet pipe, and the side of absorption box is provided with NaI scintillator probe, and NaI scintillator probe connects the gamma ray spectrometer system.
The NaI scintillator probe of existing radioiodine sampler generally all is located at the air flow inlet side of active carbon adsorption box, as shown in Figure 1, active carbon adsorption box 1 is between admission line 3 and outlet pipe 4, one side of active carbon adsorption box 1 is provided with detector 2, the probe of detector faces toward active carbon adsorption box 1, and is positioned at the air flow inlet side.Show that after deliberation this set form can constitute certain influence to detection efficiency, when air-flow passed through from adsorbing box, the flowing gas of side direction can make the detection efficiency of probe reduce, and final monitoring result is constituted influence.
Summary of the invention
The purpose of this utility model is at the defective on the existing radioiodine sampler structure, and the radioiodine sampler after a kind of the improvement is provided, thereby improves the detection efficiency of device.
The technical solution of the utility model is as follows: a kind of radioiodine sampler, comprise an absorption box that is used for adsorbing by the iodine-131 of gas production stream, the absorption box is between admission line and outlet pipe, one side of absorption box is provided with the NaI scintillator probe that is connected with the gamma ray spectrometer system, and NaI scintillator probe is over against the position of admission line air intake opening.
Further, aforesaid radioiodine sampler, wherein, admission line and outlet pipe are 90 degree angle settings.
The beneficial effects of the utility model are as follows: in radioiodine sampler provided by the utility model, NaI scintillator probe is over against the air intake opening position of admission line, air-flow blows to detecting head surface from the front, thereby can greatly increase the useful area of probe detection, improves detection efficiency.
Description of drawings
Fig. 1 is existing radioiodine sampler structure synoptic diagram;
Fig. 2 is a structural representation of the present utility model.
Embodiment
Below in conjunction with specific embodiment the utility model is described in detail.
As shown in Figure 2, the radioiodine sampler comprises an active carbon adsorption box 5 that is used for adsorbing by the iodine-131 of gas production stream, active carbon adsorption box 5 is between admission line 7 and outlet pipe 8, one side of active carbon adsorption box 5 is provided with NaI (T1) the scintillator probe 6 that is connected with the gamma ray spectrometer system, admission line 7 and outlet pipe 8 are 90 degree angle settings, and NaI (T1) scintillator probe 6 is positioned at over against the position of admission line 7 air intake openings.So, NaI scintillator probe, active carbon adsorption box and admission line air intake opening just are on the same straight line, make the lateral airflow of NaI scintillator detecting head surface greatly reduce.
After being filtered by the active carbon adsorption box by gas production stream, NaI (T1) detector is positioned at the air-flow of absorption box and just faces
131The gamma-rays of the 364keV of I emission is surveyed.In sampling and measuring process, during absorption box continuous adsorption is flowed by gas production
131I, NaI (T1) gamma ray spectrometer system continuous coverage counting.Showed the once result of current measurement in generally per 5 minutes, to obtain by in the gas production stream
131The information of the very fast variation of I concentration; Showed once in per 24 hours simultaneously
131The mean concentration of I is to improve in being flowed by gas production
131The detection limit of I.The zero clearing of per 24 hours gamma ray spectrometer system counts once.Work as appearance
131When situation that the I concentration abnormality is high or operation hours are longer, need to change a new active carbon adsorption box and with the zero clearing of gamma ray spectrometer system counts.