Neutron field measurements for alara purposes around a Van de Graaff accelerator building.
The Institute for Reference Materials and Measurements operates a 7.0 MV Van de Graaff accelerator to generate monoenergetic neutron radiation for experimental applications. Owing to increased intensities of generated neutron fields and the more stringent regulation related to the maximum dose for the public, a concrete shielding wall surrounding the experimental building was constructed. This paper presents a study aiming at evaluating the effect of the shielding on the neutron field outside the wall. For this purpose, the following measurements were carried out around the building: (1) cartography of the neutron field for different experimental conditions; (2) measurement of neutron spectra using multiple Bonner spheres; (3) activation measurements using gold discs followed by low-level gamma spectrometry. From the measurements, it can be concluded that the wall fulfils its purpose to reduce the neutron dose rate to the surrounding area to an acceptable level.
Kockerols
P
P
EC-Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, B-2440 Geel, Belgium. pierre.kockerols@cdc.en.int
Lebacq
A L
AL
Gasparro
J
J
Hult
M
M
Janssens
H
H
Lövestam
G
G
Vanhavere
F
F
D016902:Air Pollution, Indoor / Q000032:analysis*; D001822:Body Burden; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods; D006801:Humans; D008452:Maximum Allowable Concentration; D009502:Neutrons; D016273:Occupational Exposure / Q000032:analysis*; D010315:Particle Accelerators; D011785:Quality Assurance, Health Care / Q000379:methods; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D017751:Safety Management / Q000379:methods; D012680:Sensitivity and Specificity; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation / Q000379:methods*