Yttrium-90 glass microspheres are used in the treatment of liver cancer. Activity calibrations are linked to a series of experiments performed with 90Y solution surrounding non-radioactive microspheres. Through a series of measurements and Monte Carlo simulations, we have tested that experimental model, finding it to be valid. New ionization chamber measurements provide links to earlier work.

This report describes the use of five electroscopes used as national standards for radioactivity for the United States during the early 20th century. This set of instruments were used for the calibration of thousands of radium-226 sources used in medical therapy in the US from 1913 to 1989. The provenance of these instruments is recorded here to aid historians and curators in preservation of knowledge and artifacts of early radioactivity measurements in the United States.

The Cavezzo meteorite was recovered on January 4th, 2020, just three days after the fall observed over Northern Italy by the all-sky cameras of the Italian PRISMA fireball network. Two specimens, weighing 3.1 g (F1) and 52.2 g (F2), were collected in the predicted strewn-field and the meteorite has been classified as an L5 anomalous chondrite. The gamma-activity of the F2 sample was measured at the Monte dei Cappuccini underground Research Station (Torino, Italy) with a large-volume HPGe-NaI(Tl) spectrometer. Thanks to the high efficiency, selectivity, and low background of the spectrometer, we were able to detect fifteen cosmogenic radioisotopes. The presence of nuclides with half-lives down to a few days (47Ca, 52Mn, and 48V) undoubtedly confirmed the recent fall of the sample. The very low activity of 44Ti and 60Co was revealed with a particular coincidence between the HPGe and NaI(Tl) detectors. To obtain the detection efficiency, we have simulated the response of the detector with the GEANT4 toolkit, once the spectrometer’s dead layer thickness was estimated using standards of known activity. Moreover, the simulation of the Dhajala meteorite (H3/4 chondrite) measurement allowed us to verify that the self-absorption of the sample is correctly taken into account and validate our simulations. In this contribution, we focus on the coincidence optimization techniques and the detection efficiency computation.

The United States has made significant progress since the terrorist attacks in September 2001 in developing an infrastructure for standards and conformity assessment for a range of homeland security products. The 9/11 Commission, in their final report in 2004, recommended several steps to make the nation safer and better prepared to respond to national-level disasters. In particular, they recommended that private-sector organizations follow standards such as NFPA 1600-2002: Standard on Emergency Management and Business Continuity. Then-Department of Homeland Security (DHS) Secretary Tom Ridge agreed with these recommendations, and thus NFPA 1600 became “the first” DHS-adopted standard. However, it took eight years to implement a DHS program such that individual corporations could demonstrate compliance with emergency management/business continuity standards.Why did it take eight years to establish a program that everyone agreed from the start was a great idea? Multiple factors contributed to the timeline. There were two different communities involved: public sector preparedness and corporate business continuity. These two communities were represented by two different, very large agencies within DHS. The public sector was a responsibility of the Emergency Preparedness Directorate in the Federal Emergency Management Agency (FEMA); corporate interests were represented by the Office of Infrastructure Protection in the National Protection and Programs Directorate (NPPD).As the first standards executive for DHS and the director of the new DHS Office of Standards in the Science & Technology Directorate, I was responsible for assisting the department in meeting the requirements of Public Law 104-1995, the National Technology Transfer and Advancement Act. My office focused from the beginning on developing voluntary consensus standards for equipment for first responders. Although we felt we were pushing the U.S. system of standards as fast as it could go, it was not fast enough to meet the immediate needs. We constantly heard from DHS leadership that we needed Consumer Reports (CR) or UnderWriters Laboratories (UL) “certifications” for homeland security products.But the leaders at DHS did not appreciate that these private-sector organizations have developed time-honored processes to ensure that products that are accepted for comparison (by CR) or receive a label (from UL) have undergone rigorous tests to demonstrate how they perform. Neither CR nor UL, for example, had the facilities or test methods to assess whether detectors for chemical, biological, radiological/nuclear and explosives agents met basic requirements. And neither wanted to support a manufacturer's claims that these detectors could detect dangerous agents or prevent terrorists’ attacks.They were not unique in wanting to limit their corporate liabilities in these uncharted waters. The best protection for manufacturers was the “government contractor defense” (Boyle v. United Technologies Corp., 487 U.S. 500 (1988)). Suppliers of military weapons and aircraft have limited liability because the contract between the government and the supplier defines potential liabilities, with a risk-based determination of who would be responsible when they procure the defense systems.In the absence of voluntary consensus standards of performance, many public and private organizations and some federal agencies began to develop “lists” of equipment and push these lists out to potential buyers. Lists that received a lot of our attention were authorized equipment for purchase with FEMA grants monies, equipment for state and local emergency responders, and products for use in aviation protection.We worked from the outset to provide FEMA, the Transportation Security Administration (TSA), and other DHS agencies with lists of voluntary consensus standards (from ASTM International, IEEE International, the National Fire Protection Association, and others) so they could provide users with an appropriate standard alongside the homeland security product (or category of products) on their suggested buyer guides. The first standards DHS adopted were personal protective equipment (PPE) standards from NFPA and NIOSH and the American National Standards Institute's N42 IEEE standards for radiation detectors.Our approach was intended to add some rigor to the term certification by requiring third-party testing with agreed-upon test and evaluation protocols. Further, we pushed for product testing to be performed by International Organization for Standards (ISO) 17025-accredited test facilities. There were two major U.S. accrediting bodies (ABs) that already had a foothold in product testing: the NIST National Voluntary Laboratory Accreditation Program (NVLAP) and the private sector's American Association for Laboratory Accreditation (A2LA).NVLAP is not supposed to compete with the other programs unless they have a direct request from a federal agency. As director of the Office of Standards at DHS, I could request NVLAP to establish such programs, and I did that twice. We requested that they work with the DHS Domestic Nuclear Detection Office to set up the Graduated Radiation Detector Evaluation (GRaDER) program for radiation detectors. The framework for this program was the ANSI N42 IEEE standards for four classes of radiation detectors used in homeland security applications.The GRaDER program represented a great success. First responder organizations had confidence that instruments were being tested in accredited laboratories against published consensus IEEE standards. The GRaDER program was our template for how to use the U.S. system of standards to improve performance of commercial off-the-shelf equipment for homeland security applications.My second request to NVLAP was to establish a program for accredited laboratories for testing biometrics equipment. NVLAP assisted TSA in identifying appropriate standards and conformity assessment procedures for a qualified products list (QPL) for airport access control biometrics equipment. The accredited laboratories test a range of biometrics readers for personnel identification (e.g., face, fingerprint and iris).The A2LA organization already had a good foothold in the DHS legacy agencies. A signature program was their accreditation of the field office laboratories of the DHS Customs and Border Protection.A2LA was to play a much more important role with the Transportation Security Laboratory (TSL) in Atlantic City, New Jersey. The TSL had the lead for DHS testing for trace explosives detectors and x-ray scanners for aviation. TSA spends up to $2 billion per year on aviation security equipment and has an elaborate system of selecting, testing and deploying equipment to hundreds of airports. We were looking for ways to insert the U.S. system of standards into their qualified products list.The third accrediting body we worked with, the American National Accreditation Board (ANAB), was for an entirely different aspect of homeland security: private-sector preparedness.Here is where it gets interesting: the DHS Office of Policy in the Obama administration decided that the nation needed something beyond “preparedness.” They asserted that the nation's public and private sectors needed to be “resilient.” (The experts can better explain the fine distinctions among preparedness, resilience, and sustainability.) The Office of Policy began fashioning a program they called Resilience Star. This program took on a life of its own for a several years. I did my bit to assist in these efforts on resilience, including organizing conferences sponsored by the ANSI Homeland Security Standards Panel on resilience.Fortunately, the U.S. private sector, as well as state, local and tribal entities, realized soon after 9/11 that they had to take steps to protect their organizations from adverse events, whether those were terrorists’ attacks or natural disasters. Corporations had responded quickly after Hurricane Katrina in 2005 to look at their distribution systems and how they could assist communities in need. The corporate world also recognized the need for attention to business continuity standards without too much concern about umbrella labels like preparedness, resilience, sustainability, and supply chain security. The checklists provided in the business continuity standards would address all these concerns.After the terrorists’ attacks of 2001, the U.S. standards community came together with local, state and federal agencies to begin fast-track development of a number of standards to protect the nation from what were seen as imminent threats. Not all the tools for standards and conformity assessment put in place during that first decade are still in use today. The threats today have evolved to include infectious diseases, cyber security, wildfires, and other natural disasters.A national response to these threats requires new standards and conformity assessment measures. Standards development organizations and accreditation bodies are again answering the calls in these new areas, in addition to continuing their efforts to revise and update the critical standards developed to mitigate terrorists’ attacks. The priorities for new standards will always be driven by the perceived risks. The leaders at DHS S&T and NIST are continuing to work with all the DHS components and other federal agencies and partners in the private sector to strengthen the standards and conformity assessment infrastructure for homeland security and protect the nation.

The tragedy of the radium poisoning of young women dial painters in the 1920s has been the subject of best-selling books, plays, and motion pictures.With knowledge about radium and its accurate measurements in the hands of a very few scientists, what responsibilities did they have to sound the alarm and mitigate the hazards to workers and the general public?This two-part analysis looks at the role of the staff of the U.S. Bureau of Standards (the National Bureau of Standards [NBS] after 1934) in developing measurements and standards for accurate determinations of radium-226 and radon-222 that ultimately led to national standards for exposure to radioactive substances.Part I looks at the efforts of Elizabeth Hughes, with guidance from her senior colleague at the NBS, to assist dial painters with obtaining redress for their injuries.Part II examines the role of NBS in establishing the national radiation protection standards that were promulgated by the U.S. Department of Commerce (DOC) and the National Council on Radiation Protection and Measurements (NCRP).

In the late 1930s, a team of physicists from the National Bureau of Standards (now the National Institute of Standards and Technology) published eight papers on the investigation of cosmic rays in the atmosphere. Payloads launched with weather balloons, also known as radiosondes, were equipped with sensors to measure temperature, relative humidity, pressure, and radiation dose. A battery-operated telemetry system was used to continuously transmit at 60 MHz to a base station. They measured the radiation dose profiles of cosmic radiation in the atmosphere up to 21 km. Calibration of the Geiger-Müller counters with a standard radium source allowed them to calculate a radiation dose rate at an altitude corresponding to 10 kPa that was 180 times the dose rate near sea level in Washington, DC. Ascents in Washington, DC (latitude 39 degrees) and Lima, Peru (near equator) allowed them to demonstrate the effects of Earth's magnetic field on incident galactic cosmic rays; the dose rate in Peru was only half that in Washington, DC.

On 21 February 1913, a few decades before the International Bureau of Weights and Measures (BIPM) started to develop activities in the field of ionizing radiation, Marie Curie on behalf of the International Radium Commission deposited the first international radium standard at the BIPM in Sèvres.From 1913 to 1935, the international standard was taken out for comparisons at the Curie Laboratory in Paris and returned to the safe at the BIPM.This article describes how the BIPM, established in 1875 by the Metre Convention, was given the role of custodian of the international radium standard at a time when the mission of the BIPM was to maintain the two fundamental units of the Metric System and was mainly directed toward the measurements needed for geodesy, the standardization of the metric system and the establishment of length and mass standards. Through the history of the first and second international radium standards, we can oversee how the mission and role of the BIPM have evolved.

Most of the existing methods for obtaining the frequency factors make use of the trap depth (activation energy) making some assumptions about the order of the kinetics. This causes inconsistencies in the reported values of trapping parameters due that the values of the activation energy obtained by different methods differ appreciably among them. Then, it is necessary to use a method independent of the trap depth making use of the isothermal luminescence decay (ILD) method.The trapping parameters associated with the prominent glow peak of BeO (280 °C) are reported using ILD method. As a check, the trap parameters are also calculated by glow curve shape (Chen's) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods. ILD method was used for determining the trapping parameters of BeO. Results obtained applying this method are in good agreement with those obtained using other methods, except in the value of the frequency factor.

The new NIST activity standardization for 18 F, described in 2014 in Applied Radiation and Isotopes (v.85, p. 77), differs from results obtained between 1998 and 2008 by 4 %.The new results are considered to be very reliable; they are based on a battery of robust primary measurement techniques and bring the NIST standard into accord with other national metrology institutes.This paper reviews all ten 18 F activity standardizations performed at NIST from 1982 to 2013, with a focus on experimental variables that might account for discrepancies.We have identified many possible sources of measurement bias and eliminated most of them, but we have not adequately accounted for the 1998-2008 results.

Accurate measurements of radiation and radioactivity rarely rise to the level of national policy. The things that matter most to ordinary citizens do not normally include questions of science and technology. Citizens are more often concerned with issues close to home relating to commerce, health, safety, security and the environment. When questions of confidence in measurements arise, they are first directed to the ministry that has responsibilities in that area. When the required uncertainty in field measurements challenges the capability of the regulatory authorities, the National Metrology Institute may be asked to develop transfer standards to enhance the capabilities of the ministry with the mission lead. In this paper, we will consider eight instances over the past nine decades in which questions in radiation and radionuclide metrology in the US did rise to the level that they influenced decisions on national policy. These eight examples share some common threads. Radioactivity and ionizing radiation are useful tools in many disciplines, but can often represent potential or perceived threats to health and public safety. When unforeseen applications of radiation arise, or when environmental radioactivity from natural and man-made sources presents a possible health hazard, the radiation metrologists may be called upon to provide the technical underpinning for policy development.

: First responders frequently are faced with suspicious white powders, which are suspected to be biological threats such as anthrax; therefore, a need exists for an inexpensive, effective tool for pre-screening suspicious powders. This study evaluated a five-step pre-screening kit which consisted of protein and pH test strips used to evaluate the presence of a biological agent. A blind study was conducted in which various protein and pH strips were used to analyze samples consisting of a virulent Versinia pestis (Y pestis) and anthrax spores, in powdered form, along with the Critical Reagents Program (CRP) suspicious powders panel. Each powder was tested separately and with the 14 CRP suspicious powders combined with V. pestis or spores. It was found that protein detection strips did not detect the presence of spores or V. pestis when mixed with certain powders. Even though primarily there was little matrix interference observed, there were several circumstances when there was a significant masking effect that precluded the accurate detection of the biological threat agent. Therefore, based on the outcome of these studies, the five-step pre-screening kit is currently not recommended to first responders for use in the differentiation of a true threat from a hoax.

Graphical presentation of data can provide useful information about variations and trends. This type of presentation is also well suited for demonstrations to laboratory personnel and others who might need to examine the stability of calibration measurements as a function of time. In addition, a large amount of data can be presented graphically in a control chart format. Comparisons between measurements performed many years ago can easily be compared with recent data. Although most of these same characteristics can be attributed to the format of data presented in the tabular form, it is often easier to detect small problems with the data when presented in a graphical form. In a control chart, data can be plotted either as ratios relative to a reference value or simply as the numerical values of the measured quantity. Normally, these values are plotted as a function of time. Graphical indicators of deviation levels that should trigger investigation or action can be plotted above and below an expected value for the measurand. A typical control chart is shown in Figure 4.1. As an example, two indicators can be placed at positions that represent expected statistical uncertainty for the measurement. For instance, indicators can be placed at set percentage variations from the reference value. A data point that exceeds this indicator is easily visible and can trigger an investigation of a possible change in response. A second set of indicators can be placed at a larger variation value, and data points falling outside these indicators might require a work-stoppage and correctiveaction plan. It is appropriate to record notes as to the cause of the deviation and the rectification of the problem that caused that deviation. In some situations, the indicators or control levels might not be symmetric with respect to the mean or reference value. This could occur when it is important not to allow the measurement to fall below a certain value. For example, the dose needed to sterilize a medical product is a critical parameter, and serious consequences result if the dose is not delivered. 4.2 LONG-TERM STATISTICAL ANALYSIS OF DATA

It is necessary to record any information that is relevant to the quality of the measurements or calibrations performed. Values for influence quantities (see Section 3.2) are to be included in a record, but additional information can at times be required. Measurements and calibrations are nearly always repeated on a regular basis. In order to ensure that subsequent measurements of the same quantity are duplicated as nearly as possible, as much information as is practical should be recorded. When the results of measurements are provided to a user, it is necessary to prepare a report that will include some, or all, of the information recorded by the measurement laboratory. As an example of the types of items that should be recorded on a calibration certificate, the following list is provided:

The assurance, or verification, of the level of quality of measurements is essentially a three-step process. First, the acceptable uncertainty must be established, usually on the basis of a published standard or national regulation. Second, a facility must have procedures in place that will lead to performance within the specified uncertainty. Third, the facility must demonstrate its capability of performing measurements within the specified uncertainty. An additional related concept that follows from the third step is a plan for remedial action when a facility fails to perform within this specified uncertainty. Measurement quality can be evaluated using a variety of techniques. Perhaps the simplest method for evaluating the quality of a measurement is the direct comparison to a national standard. For instance, a working-level ionization chamber may be periodically compared with a reference or transfer standard that has in turn been compared with a national standard. If the value measured using the chamber agrees with the value measured using the reference standard chamber to within a specified uncertainty, then the measurement quality is assured. If the difference is greater than the expanded uncertainty (see Section 5.2) the cause of this difference should be investigated and appropriate remedial action taken. Until the discrepancy is resolved, no measurements should be used or disseminated. Any such measurement disseminated, but also affected by the discrepancy, shall be identified and appropriate action taken (e.g., informing the customer).