Download or read book A Small Inexpensive Albedo neutron Dosimeter written by Dale E. Hankins and published by . This book was released on 1973 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Albedo Neutron Dosimeters written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design, operation, calibration, and performance of albedo neutron dosimeters are discussed. An albedo neutron dosimeter is designed to measure the flux of thermal neutrons which leave the body when a person is exposed to fast energy neutrons. The fast neutrons are scattered and moderated in the body, and many have lost most of their initial energy and emerge as thermal neutrons. The albedo neutron dosimeter is designed to detect this flux of thermal neutrons by using a thermal neutron detector. This could be any type of thermal neutron detector but in practical applications lithium fluoride (LiF) thermoluminescence dosimeters (TLDs) are most frequently used. Various types of albedo neutron dosimeters are described. (WHK).

Download or read book Energy Dependence of Albedo Neutron Dosimeters Placed on the Head written by Dale E. Hankins and published by . This book was released on 1970 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Factors Affecting the Design of Albedo Neutron Dosimeters Containing Lithium Fluoride Thermoluminescent Dosimeters written by Dale E. Hankins and published by . This book was released on 1972 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Wrist Albedo Neutron Dosimeters written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We are developing a wrist dosimeter that can be used to measure the exposure at the wrist to x-rays, gamma rays, beta-particles, thermal neutrons and fast neutrons. It consists of a modified Hankins Type albedo neutron dosimeter and also contains three pieces of CR-39 plastic. ABS plastic in the form of an elongated hemisphere provides the beta and low energy x-ray shielding necessary to meet the requirement of depth dose measurements at 1 cm. The dosimeter has a beta window located in the side of the hemisphere oriented towards an object being held in the hands. A TLD 600 is positioned under the 1 cm thick ABS plastic and is used to measure the thermal neutron dose. At present we are using Velcro straps to hold the dosimeter on the inside of the wrist. 9 figures.

Download or read book New Technique to Improve the Accuracy of Albedo Neutron Dosimeter Evaluations written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The calibration factor for albedo neutron dosimeters varies greatly depending upon the energy of the neutrons in the exposure. Calibration results obtained over an eight-year period at each Lawrence Livermore National Laboratory facility where neutron exposure may occur were reviewed. A stronger relationship than expected was found between the ratio of the readings of the 9-in. to 3-in. spheres and the percent thermal. Readings from personnel and albedo badges were reviewed. The readings were consistent with the use of a calibration factor for the albedo dosimeter which varies with changes in the ratio of the personnel and albedo dosimeter TLD readings. 2 references, 6 figures. (ACR).

Download or read book The Response of an Albedo Neutron Dosimeter to Moderated AmBe and 252 Cf Neutron Sources written by A. E. Nash and published by . This book was released on 1985 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The response per Rem of an albedo neutron dosimeter has been determined for 56 neutron spectra which were generated by moderating AmBe and 252 Cf (Californium 252) neutron sources with various combinations of Lucite, polyethylene, and steel. The spectra were determined by using Bonner spheres and were further characterized by using commercially available 9-in., 3-in., and bare BF3 (Boron Fluoride) tube detectors and an Anderson-Braun-type Remmeter. The average energy of the spectra ranged from approximately 0.4 to 4.5 MeV. The ratio of the 3-in. detector response to the 9-in. detector response varied from about 0.3 to 3, and the ratio of the bare detector response varied from 0.04 to 3. The response per Rem of the albedo dosimeter, a 6 LiF-7 LiF (Lithium Fluoride) detector pair behind a cadmium shield encased in a plastic badge, varied by more than a factor of seven. Our experiments showed that for this type albedo dosimeter, the bare to 9-in. detector ratio is more appropriate for reducing energy dependence than the 3-in. to 9-in. ratio, which is recommended for completely cadmium-encased albedo dosimeters, and is often used for other types of albedo dosimeters. Using both ratios gives optimum results; the average error due to energy dependence was reduced to about + or - 10%. Using the response ratio of a detector in front of the cadmium shield to the one behind the shield to correct for energy dependence was also effective for these spectra; the average error was approximately + or - 20%. Keywords: Personnel radiation monitoring; Radiation dosimetry; Neutrons. (Author).

Download or read book Correcting the Response of an Albedo Neutron Dosimeter for Energy written by and published by . This book was released on 2007 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron response of an albedo neutron dosimeter varies greatly with energy. For example, the dosimeter, calibrated with moderated Californium fission neutrons, will read more than 30 times the dose from thermal neutrons and less than 3% of the dose from 14 MeV neutrons. To report a correct result, the measured dose equivalent is multiplied by a neutron energy correction factor (NECF). Two techniques for finding the NECF were developed through a cooperative effort among the Naval Research Laboratory, the Naval Surface Warfare Center, and the Naval Dosimetry Center. Data for the DT-702 (measured in 5 different neutron spectra) matched data for the DT-648 dosimeter from 15 spectra that included an SSBN and the NATO standard battlefield spectrum. NECFs calculated from count rate ratios of the AN/PDR-70 neutron remmeter (rem) to its internal parts (guts) or from the ratio of the inner to the outer neutron dosimeters in the DETECTOR RADIAC SS-20/S (NAM-5) make the DT-702 dosimeter about as accurate as the AN/PDR-70 neutron remmeter.

Download or read book Albedo neutron Dosimetry Studies at Lawrence Livermore Laboratory written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarized studies performed since the last workshop meeting. The studies have been divided into four sections: (1) the relative response of Hankins-type albedo-neutron dosimeters made of cadmium and boron; (2) the effect of distance from the body on the response of albedo-neutron dosimeters; (3) the use of the ratio of the top to bottom TLDs to determine the calibration factor for albedo-neutron dosimeters; and (4) neutron survey at a power reactor and at a neutron radiography facility.

Download or read book Neutron Response of a New Albedo neutron Dosimeter written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Los Alamos Scientific Laboratory is converting from a film badge to a badge containing thermoluminescent dosimeters (TLD's). The new dosimeter consists of a plastic badge holding an aluminum card which contains three TLD-700 and one TLD-600 Harshaw LiF chips. In the albedo-neutron portion of the badge, based on Hankins' design, the TLD-600 and one TLD-700 chips are shielded from thermal neutrons by 0.026-inch-thick cadmium. From the difference in readings of these two TLD's, the neutron dose is estimated. There is also a detachable holder for NTA film if needed to cover the neutron energy range not covered by the albedo-neutron badge. The neutron energy response of the new badge was measured, using monoenergetic sources over the range from 0.1 to 14 MeV and is compared with a calculated response over this range. Since NTA film cannot detect proton recoils from neutrons with energies less than 0.7 MeV, a primary advantage of the TLD albedo-neutron badge is its ability to record neutrons down to the cadmium cutoff. However, a major disadvantage is its sharp decrease in sensitivity with increasing energy. Data are given showing this. Using a BF3 detector inside 9-inch and 3-inch polyethylene spheres containing cadmium, Hankins developed a method for applying energy calibration factors to the albedo-neutron TLD badge readings. This method is based on two premises: first, that the response in rem of the 9-inch sphere is independent of energy and second, that the response of the 3-inch sphere is similar to that of the TLD albedo-neutron badge. Measurements to test the validity of these premises are reported. The method requires initial 9-inch to 3-inch sphere ratios to be measured in each area where neutrons are encountered and periodic checks to detect changes which may occur.

Download or read book Effect of Energy Dependence on the Evaluations of Albedo Neutron Dosimeters written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Albedo neutron dosimeters have proven to be effective as a method of measuring the dose from low-energy neutrons that other types of personnel neutron dosimeters do not detect. Many albedo neutron dosimeters have been designed, and some are being used extensively. All albedo neutron dosimeters are energy- dependent, becoming less sensitive as the energy of the neutrons is increased. In this paper the energy dependence and the effect it has on the evaluation of the dose are discussed. Numerous measurements are shown which were made under field conditions at five reactors, two accelerators, a radiochemistry facility, two plutonium facilities, a low-scatter neutron irradiation facility, three storage vaults, and at the N.B.S. low-energy neutron beams. These measurements show the limits imposed by the energy dependence on the evaluation of the dose determined by albedo neutron dosimeters. In most cases evaluation of an individual's dose occurring in a single facility can be reasonably accurate, but it must be known in which facility the person was exposed. Procedures using the incident thermal neutron response of TLDs located on top of the dosimeter to correct for the energy dependence are discussed; and errors caused by wearing a dosimeter improperly are evaluated. (auth).

Download or read book Angular Dependence of Dose Equivalent Response of an Albedo Neutron Dosimeter written by Betty Ann Torres and published by . This book was released on 1994 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Response of an Albedo Neutron Dosimeter to Moderated AmBe and 252Cf Neutron Sources written by and published by . This book was released on 1985 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of TL Albedo Neutron Dosimeters written by J.A. Douglas and published by . This book was released on 1976 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling the Response of a Harshaw Albedo Neutron Dosimeter Using the Monte Carlo N particle Transport Code MCNP written by Christina Beth Pomatto and published by . This book was released on 1998 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Composite Damage Track albedo Personnel Neutron Dosimeter for General Use written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: No known detector or series of detectors in personnel neutron dosimeters have correct dose equivalent energy-dependence. Useful dosimeter performance is assumed by calibrating dosimeters for the exposure spectrum. This method implies that the exposure spectrum will be constant within a given facility or the wearer will not be exposed to different spectra in other areas. Since exposure spectra are known to vary widely a composite damage track-albedo personnel neutron dosimeter was developed to separately respond to the softer and more energetic parts of various spectra. The relationships of the responses of the elements vary with different spectra and are used to convert dosimeter readings to dose equivalent. Measurements indicate that dose equivalent deviation was less than approximately 50 percent for unshielded lucite and steel shielded HPRR spectra, monoenergetic spectra from 4.7 to 15 MeV, a 252Cf spontaneous neutron spectrum and an AmBe spectrum. Dosimeter sensitivity was similar to present NTA film methods. The composite personnel neutron dosimeter was also tested with calculated spectra by simulating badge response through known energy-dependence of the badge elements. Dose equivalent deviation was less than approximately 20 percent for 19 significantly different assumed spectra. Thus, the experimental and calculational results support adherence to the dose equivalent for common exposure spectra. (auth).

Download or read book Personnel Albedo Neutron Dosimeter with Thermoluminescent 6LiF and 7LiF written by and published by . This book was released on 1972 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: