ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
The Frisch-Peierls memorandum: A seminal document of nuclear history
The Manhattan Project is usually considered to have been initiated with Albert Einstein’s letter to President Franklin Roosevelt in October 1939. However, a lesser-known document that was just as impactful on wartime nuclear history was the so-called Frisch-Peierls memorandum. Prepared by two refugee physicists at the University of Birmingham in Britain in early 1940, this manuscript was the first technical description of nuclear weapons and their military, strategic, and ethical implications to reach high-level government officials on either side of the Atlantic. The memorandum triggered the initiation of the British wartime nuclear program, which later merged with the Manhattan Engineer District.
Runqiu Gu, Jianfeng Cheng, Wanchang Lai, Xianli Liao, Guangxi Wang, Juan Zhai, Chenhao Zeng, Jinfei Wu, Xiaochuan Sun
Nuclear Technology | Volume 208 | Number 5 | May 2022 | Pages 912-921
Technical Paper | doi.org/10.1080/00295450.2021.1957661
Articles are hosted by Taylor and Francis Online.
The characteristic X-ray of a target is of considerable significance in industrial applications and medical diagnosis and treatment, and its intensity is closely related to the incident electron energy. At a high energy, it is not easy to determine the relation between characteristic X-rays and the incident electron energy through measurements, but the Monte Carlo method has a wide energy calculation range. In this study, the X-ray energy spectra of six target materials (Cu, Mo, Rh, Ag, W, and Pt) were simulated at various incident electron energies (<3 MeV) using the Monte Carlo code MCNP5 and the relation curve between the characteristic X-ray intensity of each of the target materials, and the incident electron energy was obtained through a simulation. A Si-PIN detector was used to measure the low-energy output energy spectra of two X-ray tubes (Ag and W targets). The relation curve between the X-ray tube excitation voltage and the characteristic X-ray intensity was obtained by fitting the measured data to a linear function. The simulation fitting curve and measurement fitting curve agreed well in the low-energy range. Comparisons of the calculated and measured values revealed that most of the deviations for the Ag target were less than 5%, and those for the W target were less than 6%.