GB/T 39325-2020 in English
VALIDSpecification for radiation shielding of superconducting proton cyclotron
- Issued on:2020-11-19
- Implemented on:2021-06-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 39325-2020超导回旋质子加速器辐射屏蔽规范》由TC58（全国核能标准化技术委员会）归口，TC58SC2（全国核能标准化技术委员会辐射防护分会）执行，主管部门为国家标准化管理委员会。
Introduction
Analysis of the core content of the standard
This standard establishes a complete shielding design technology system for the special radiation protection needs of superconducting cyclotron proton accelerator, mainly covering:
- Shielding applicability of proton energy range 70-1000MeV
- Secondary neutron yield calculation model (Formula 1-3)
- One-tenth value layer data of materials such as concrete/baryte concrete/iron
- Special considerations for sky scatter and side scatter radiation
Comparison of key technical parameters
| Parameters | Ordinary concrete | Baryte concrete | Iron |
|---|---|---|---|
| Density (g/cm³) | 2.35 | 3.2 | 7.4 |
| TVL₀(cm) | 162 | 139 | 82 |
| 220MeV proton TVL | 108 | 93 | 55 |
Key points of secondary neutron protection
Take 220MeV proton beam as an example:
- Secondary neutron yield 0.63 neutrons/proton (Formula 1)
- Forward radiation dose rate 0.27Sv/h@1m (1.6nA beam current)
- Concrete shielding requires 381cm to achieve a control level of 2.5μSv/h
Note: The calculation adopts the 1.5th power inverse law to conservatively consider the wall reflection effect
Implementation suggestions
Design phase
- Integrally cast concrete structure is preferred
- The width of the maze must be ≥1.5 times the equipment transportation size
- The through-hole adopts a Z-shaped bend design
Operation phase
- Periodically conduct shielding integrity testing
- It is recommended to add a boron-containing polyethylene layer on the inner surface of the maze
- Establish a Monte Carlo model to verify the hot spot area
Sample only — not a preview of GB/T 39325-2020
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