We have been using HPGe detectors for evaluating the level of natural and artificial radionuclides in different kinds of environmental samples. Parallelly, we also provide radioactivity testing services to ensure that there are no consequences triggered due to the consumption of highly radioactive food materials. We usually use certified reference material (CRM) collected from IAEA for calibration, performance evaluation (PE), method validation (MV), and QC. We are planning to collect a CRM of milk powder spiked with Cs-137...but could not find it anywhere? Could anyone of you please help me find it? It is urgent for us as we are working on getting ISO17025 accreditation by this year.
Hi
You can use SRIM software, please check the official page of the organization
http://www.srim.org/
Hi Akm Saiful Islam Bhuian ,
Isn't it appropriate to use a commercial Calibration Standards Source [1] buried in a can of milk powder for measurement? The energy of Cs-137 gamma rays is as high as 662 keV, so I think the absorption of Cs-137 by the powdered milk or can is small. If you are concerned about this, you may do a Monte Carlo calculation as Asaad Hamid Ismail pointed out.
[1] Eckert & Ziegler Reference & Calibration Sources; https://www.jrias.or.jp/products/pdf/20090401-135217.pdf
Dear Dr. Kengo Shibuya Sensei, thanks a lot for the answer you provided. We used to do the same you recommended for years. But our laboratory is going through the process of getting ISO 17025:2017 accredited. According to the requirement, we must use certified reference material (CRM) for the calibration and method validation process. IAEA used to sell milk powder CRM, and we had one which is now unusable due to low activity. IAEA is not producing that anymore, so we are looking for an alternative vendor for CRM. However, if we could not find one we will prepare the one as you suggested. I was trying to do a MonteCarlo calculation for evaluating the absorption of Cs-137 in milk powder, but I'm confused about some input parameters. Please check the attached file, and if possible, please let me know what to insert in the TARGET tab.
Dear Dr. Asaad Hamid Ismail, thanks for your suggestion.
Dear Akm Saiful Islam Bhuian
I am not a software expert. If you need to calculate the gamma-ray interaction in detail, I suggest you start a new question thread. The screen you are showing looks like you are trying to inject the specified ion beam into the target material. What do you think, Asaad Hamid Ismail?
It seems the following programs are used for simulating gamma-rays.
- Geant4 https://geant4-data.web.cern.ch/ReleaseNotes/ReleaseNotes4.10.5.html
- PHITS https://phits.jaea.go.jp/index.html
- EGS5 https://rcwww.kek.jp/research/egs/index.html
Kengo Shibuya Sensei, thanks once again. I will try with PHITS...
Akm Saiful Islam Bhuian-san, I wish you the best of luck with PHITS. According to Bergogni-Tribondeau's law, tissues with more proliferating cells tend to be more sensitive to radiation, and infants are more sensitive to radiation than adults because of their active cell proliferation as they grow. It is vital that there is greater safety with regard to radioactive isotope contamination of milk powder by your work.
Kengo Shibuya SEnsei, I usually use PHITS for studying the radiation damage in nuclear materials. We are aware of the vulnerability of the infants due to the possible internal exposure to ionizing radiation.
Bergonie-Tribondeau's law based on experimental observations in rat testes applies at cellular levels (albeit with various exceptions such as lymphocytes, some gonadal cells, AT cells, and SV40-transformed cells), but less generally at tissue or organism levels. Younger people are not necessarily radiosensitive than older people where dependence of radiosensitivity on age (e.g., age at exposure, attained age) greatly differs by endpoints (health outcomes). For instance, children are more radiosensitive than adults for about 25% of cancers (e.g, leukemia, thyroid, skin, breast and brain cancers), as detailed in
https://www.unscear.org/docs/publications/2013/UNSCEAR_2013_Report_Vol.II.pdf
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