D. M. Verrelli - Storming Media

Reactor Dosimetry with Diodes, Pocket Dosimeters, and Paired Chambers.

OCT 1973

Authors: G. E. Tumbraegel; D. W. Shosa; D. M. Verrelli; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

The full text of this report is not available and therefore is not for sale. This information is provided for reference purposes only.

Paired ionization chambers with nominal volumes of 0.5 cc have been used for measuring the neutron and gamma ray dose components in different AFRRI-TRIGA reactor fields. The results of these measurements have been compared with measurements made with other dosimetry systems such as wide based silicon diodes and pocket dosimeters. The saturation behavior of the pocket dosimeters has been tested by exposures with the AFRRI LINAC. Results indicate that the ...

Reduction of 41Ar Environmental Releases at Research Reactors.

AUG 1973

Authors: D. M. Verrelli; R. E. Carter; L. A. Slaback Jr; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

The reactor facility at the Armed Forces Radiobiology Research Institute consists of a TRIGA Mark-F reactor with two large walk-in exposure rooms and a pneumatic tube facility. Operation of the reactor adjacent to these rooms results in signigicant 41Ar production rated due to the high thermal neutron leakage from the core and from the albedo off the walls. The leakage and albedo have been reduced by placing panels painted with ...

AFRRI Cobalt Whole-Body Irradiator.

MAR 1973

Authors: Robert E. Carter; D. M. Verrelli; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

The AFRRI cobalt irradiator contains two sets of sources, allowing for either unilateral or simultaneous bilateral irradiation of large animals or objects. With a loading of 25 kCi of 60Co, exposure rates up to 400 R/minute are possible. The exposure rate can be varied either by changing the number of source rods or by changing the source to target distance. A brief description of the facility and the results of ...

Factors Affecting the Performance of Primates Following a 2700-Rad Pulsed Dose of Ionizing Radiation.

AUG 1972

Authors: G. C. Brown; C. R. Curran; D. M. Verrelli; S. J. Allen; D. J. Barnes; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

The performance of eight monkeys (Macaca mulatta), trained at the USAF School of Aerospace Medicine to operate a primate equilibrium platform (PEP), was tested following a single pulse, whole-body 2700-rad (plus or minus 200 rads) dose of neutron-gamma radiation at the AFRRI-TRIGA reactor (n/g = 0.5:1, pulse half-width of 50 msec). The results were compared to: (1) PEP-trained animals exposed to a 2500-rad pulse of neutron-gamma radiation at the White ...

The Relative Effectiveness of Fission Neutrons for Gastronintestinal Death in Miniature Pigs.

DEC 1971

Authors: S. R. Jones; R. E. George; J. E. West; D. M. Verrelli; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Miniature pigs were bilaterally irradiated either in a neutron field (incident neutron to gamma ratio of 5) or in a gamma ray field (incident gamma to neutron ratio of 15) from the AFRRI-TRIGA reactor. For both fields the dose rate at the midline of the pigs was 250 rads/min and uniform (class A) irradiations to the gastronintestinal (GI) tract were achieved. Midline tissue doses from the neutron field ranged from ...

Comparison of Dose Patterns in a Miniature Pig Exposed to Neutron and to Gamma Radiation.

OCT 1971

Authors: D. M. Verrelli; D. W. Shosa; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Depth-dose patterns were compared for significantly different mixtures of incident radiations from the AFRRI-TRIGA nuclear reactor. Neutron to gamma ray tissue kerma ratios of 10:1 and 0.06:1 were used for exposure of a miniature pig cadaver. Measurement of the dose distribution patterns across the brain and across the intestinal regions was performed employing the paired ionization chamber technique. Placement of the dosimeters within the cadaver was verified by radiography and ...

Dosimetry for Neutron Radiation Studies in Miniature Pigs.

MAY 1971

Authors: D. M. Verrelli; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Miniature pig cadavers were instrumented and irradiated in a neutron field (incident neutron to gamma kerma ratio of 5-10) and a gamma ray field (incident gamma to neutron kerma ratio of 10-15) from the AFRRI-TRIGA reactor. Characterization of the radiation field included free-in-air measurements of the neutron and gamma ray components employing the paired chamber concept. Depth-dose patterns across the brain and intestinal regions were measured for each of the ...

The Relative Effectiveness of Fission Neutrons for Miniature Pig Performance Decrement.

MAR 1971

Authors: R. E. George; R. L. Chaput; D. M. Verrelli; E. L. Barron; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Trained miniature pigs were whole-body irradiated in a nuclear reactor-produced neutron field (incident neutron to gamma ratio of 10). Their postirradiation performance was compared to that of pigs similarly irradiated in a gamma ray field from the same reactor (incident neutron to gamma ratio of 0.06). The dose rate at the midline of the brain was approximately 2000 rads/min for all irradiations; midbrain doses ranged from 1500 to 36,500 rads. ...

A BRIEF DESCRIPTION OF THE AFRRI-TRIGA MARK F REACTOR METHODS FOR CONTROLLING DISCHARGES, ENVIRONMENTAL SURVEILLANCE AND EMERGENCY PLANS.

JUL 1966

Authors: S. W. Porter; D. M. Verrelli; ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

The Armed Forces Radiobiology Research Institute Triga Mark F Reactor and associated experimental facilities are briefly described. A unique perimeter monitoring system is discussed. The remote area monitoring system along with the radioactive liquid and gaseous handling and waste disposal systems are outlined. A brief discusssion of emergency procedures is included. (Author)