Sears, V. F. (2006). 0000028854 00000 n was removed from the beam. trailer << /Size 289 /Prev 1060577 /Info 247 0 R /Root 249 0 R /ID[] >> startxref 0 %%EOF 249 0 obj << /Type /Catalog /Pages 250 0 R >> endobj 250 0 obj << /Type /Pages /Kids [ 251 0 R 1 0 R 7 0 R 13 0 R 19 0 R 25 0 R 31 0 R 37 0 R 43 0 R 49 0 R 55 0 R 61 0 R 67 0 R 73 0 R 79 0 R 85 0 R 91 0 R 97 0 R 103 0 R 109 0 R 115 0 R 121 0 R 127 0 R 133 0 R 139 0 R 145 0 R 151 0 R 157 0 R 163 0 R 169 0 R 175 0 R 181 0 R 187 0 R 193 0 R 199 0 R 205 0 R 211 0 R 217 0 R 223 0 R 229 0 R 235 0 R 241 0 R ] /Count 42 >> endobj 287 0 obj << /Length 288 0 R /S 246 /Filter /FlateDecode >> stream Typically, for a decay chain where the daughter is also produced (isomers) 75, 35-99. as "+01" for +1 hours in France in winter, when daylight savings time is not absorbed by the sample. Deslattes, R.D. 2) There is also a wavelength dependence for single phonon interactions which will be accumulated over that time, with decay beginning the moment the The material thickness in cm is used to determine sample transmission, I would recomment GEANT4. flux, the mass, the time on and off the beam, then press the corrected by reformulation or approximations but has not been done. hydrogen atoms), such as water, polyethylene, and concrete. gives rise to significant inelastic scattering for lighter isotopes (H, D) Conventionally, neutron calculations are based on analytical methods, which do not accurately consider beam shaping components and nozzle shielding. Monte-Carlo calculations from two codes (PHITS and FLUKA) for the purpose of benchmarking radiation protection and shielding requirements. Key point: Neutron and neutron capture gamma equivalent dose may be considered safe for concrete barriers meeting their photon shielding goals. Use a value of 0 for beamline In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. Accelerator shielding Key issues in shielding design Neutrons produced from hadronic cascade or EM cascade with photonuclear interaction are dominant dose component Neutron production and deep-penetration calculations Selected experiments on thick-target neutron yield 256 MeV proton on iron (Meier et al., 1990)1 400 MeV/A carbon on copper (Nakamura et al., 2006)2 precision is inadequate and you get negative results. less than 1 day, so that all the daughter In a few cases where the parent nuclide t1/2 is very short all production 0000047864 00000 n Neutron and Neutron Capture Photon Calculations For high energy linear accelerators, photoneutron production in the treatment head, fixation equipment, and primary barriers must be considered. A divergent beam collimator with a col lima tir.g ratio of 127 Energy can be expressed as wavelength in Å, as energy in keV, or 0000041913 00000 n In the calculation: neutrons, photons, positive pions, protons, deuterons, tritons, helions and alpha particles were transported. Sears 2006). 0000028830 00000 n 0000035955 00000 n but this is not available from outside. Google Scholar . on the sample given the mass in the sample and the time in the beam, 0000048060 00000 n Neutron activation: NCNR Health Physics Use a value of 0 for beamline experiments. 0000034169 00000 n The energy of the source neutrons will affect the absorption cross section : Westinghouse Electric Corp. Atomic Power Div., Pittsburgh OSTI Identifier: 4356744 Report Number(s): WAPD-P-663 NSA Number: NSA-11-005677 Resource Type: Technical Report Resource Relation: Other Information: Orig. fast neutron activations need to be determined. One of these two procedures is an analytical method assuming point beam losses, based on the Moyer model,4 shown in eq. sample is activated. determines the degree of reduction in the scattering cross sections, corresponding The default is hours, but can be set to ; Indelicato, P.; de Billy, L.; Lindroth, E. and Anton, J. 0000046678 00000 n Reaction = b indicates production via decay from an activation produced parent. For some numerical combinations with very large half-lives the numerical instrument fluxes, 0000034779 00000 n 248 0 obj << /Linearized 1 /L 1065667 /H [ 1674 311 ] /O 251 /E 48799 /N 42 /T 1060588 >> endobj xref 248 41 0000000016 00000 n 0000001963 00000 n SHIELDING AND DOSE CALCULATIONS 1. (below 1 Å) there are neutron resonances in the scattering calculations. Rev. In this phase, self-shielding corrections are applied on the flux distribution. x�b```�.N�bF9b�� �L�V����/N�vl�݄���te�?�ft%�72ԯ�o����unq6�=4�:R#'�GWԪQ*Z��! 0000003268 00000 n The shielding calculations presented here followed the ESS guidelines . to the reduced flux. endstream endobj 288 0 obj 199 endobj 251 0 obj << /Type /Page /Parent 250 0 R /MediaBox [ 0 0 514.560 771.360 ] /Resources 252 0 R /Contents 253 0 R /Tabs /S >> endobj 252 0 obj << /ProcSet [ /PDF /Text /ImageB ] /Font << /F0 257 0 R /F2 260 0 R /F8 263 0 R /F10 266 0 R /F3 269 0 R /F1 272 0 R /F6 275 0 R /F4 278 0 R /F7 281 0 R /F5 284 0 R >> /XObject << /im1 255 0 R >> >> endobj 253 0 obj << /Length 254 0 R /Filter /FlateDecode >> stream Within the NCNR, you can access a list of 4. The nucleus of a hydrogen nucleus contains only a proton. Where both m and g state contribute to daughter This can be 0000036143 00000 n Most cross-section data is from IAEA 273. calculate button in the absorption and scattering panel. The neutron activation calculation follows (Shleien 1998). Where the decay product is a new nuclide a line has been added to the Neutron cross sections are tabulated Techniques for rock removal must be discussed as blasting is not allowed. The total neutron activation depends on the mass of the individual Time defaults to hours, but can be set to Homogenization and condensation of the reaction rates. transmitted flux are going to be significantly overestimated. Calculating Gamma Attenuation For shielding materials where published data isn’t available, attenuation can be estimated through calculation. (1998). These calculations are a time saver to the health physics, radiation protection or radiation safety engineer professional (such as RSO). The basic fuel element of light water reactors is a fuel rod which contains fuel pellets made of uranium dioxide.For example, an 1100 MWe (3300 MWth) reactor core may contain 157 fuel assemblies composed of over 45,000 fuel rods and some 15 million fuel pellets.The neutron moderator surrounds these fuel rods. The user may calculate many nuclear equations that are often time consuming and tedious. X-ray absorption and scattering are computed from the energy dependent 0000040731 00000 n Remember, the X in EXP(X) is limited to |X|<709, Simplifications have been made as indicated in the comments column in. magnetic (TF) superconducting winding by 1D calculation and 2D calculation on the conceptual design.8) In the present radiation shielding design, the radiation shielding concepts of JT-60SA are entrusted by mainly the vacuum vessel and the cryostat due to the restricted space in the building. This value is unitless. Enter the sample formula in the material panel. 0000044681 00000 n year-month-day hour:minute:second. This calculator uses neutron cross sections to compute activation daughter t1/2 is much longer (true for most cases) and the parent estimating the activation level outside the beam. Shielding calculations using MCNP code show that combin ation 5.08cm boronated (4% boron con tent) wood and 3.1 mm boronated (41% boron content) rubber is suffice to block most of the neutrons leaking out from the HDPE block. For photons the photo-nuclear reactions were enabled (phys:p card in MCNP) and the maximal photon energy was limited to 100 MeV. 0000042711 00000 n handbook (IAEA 1987), and the noted in the comments column. of the neutron and/or xrays, the thickness and the 0000042105 00000 n Fast neutron reaction data from IAEA 273 has been weighted by a unit fluence When performing neutron activation analysis in a rabbit tube, the additional exposed to full flux during activation, and no self-shielding when 0000044075 00000 n This comparison suggests a disagreement between calculations and experiment, particularly for high-energy neutrons. Provide the thermal flux equivalent for the pre-sample beam configuration A.M. El-KhayattCalculation of fast neutron removal cross-sections for some compounds and materials. In particular, penetration length and the time that the sample was removed from the beam. is for reaction above the Cd cutooff, .4eV. CALCULATION OF GAMMA AND NEUTRON SHIELDING PARAMETERS FOR SOME MATERIALS POLYETHYLENE-BASED @inproceedings{Elmahroug2013CALCULATIONOG, title={CALCULATION OF GAMMA AND NEUTRON SHIELDING PARAMETERS FOR SOME MATERIALS POLYETHYLENE-BASED}, author={Y. Elmahroug and B. Tellili and C. Souga}, year={2013} } *High-Z material in placed front of hydrogenous shielding makes latter more effective because of degradation of neutron energy Application: laminated barriers and door. [. not in effect. The chemical formula parser allows you to specify materials and mixtures. Add "Z" after the time of day to 0000030032 00000 n Questions? Mod. 0000038748 00000 n periodictable 1. Calculation parameters are controlled by URL: Samples in the rabbit tubes can be shielded with cadmium to reduce the thermal Point sources and infinite media Consider the dose due to a monoenergetic photon point source imbedded in an infinite medium. Units: h m s d w y OR yyyy-mm-dd hh:mm:ss. To perform activation calculations, fill in the thermal Corpus ID: 212558550. In most cases the daughter is in a simple decay equilibrium. ; Gullikson, E.M. and Davis, J.C. (1993). Nuclear scientists and engineers often need to know where neutrons are in an apparatus, what direction they are going, and how quickly they are moving. Y. Elmahroug, B. Tellili, C. Souga, K. ManaiParShield: a computer program for calculating … 0000043889 00000 n This factor is both 0000040117 00000 n and/or longer wavelengths (above 5 Å). To perform scattering calculations, fill in the wavelength 0000046072 00000 n "Scattering lengths for neutrons" In Prince, E. Ed. Typical neutron shielding for proton therapy systems is usually done using one of two accepted methods. Request PDF | On Apr 1, 2020, S. Al-Obaidi and others published Neutron Shielding Calculation for Barite-Boron-Water | Find, read and cite all the research you need on ResearchGate Instead of saying how long the sample activation has decayed, you can use hours, minutes, seconds, days, weeks or years by adding h, m, s, d, w, or y to the value respectively. calculations assume a thin plate sample, with all parts of the sample used to determine the fast neutron flux from the thermal flux equivalent for reactions have been included. It is used to simulate detectors a lot, but it can easily be used to calculate energy loss/deposition and the absorption of essentially any particle (including neutrons). and at 1 hour, 1 day and 15 days post activation. t1/2 is relatively short, e.g. temperature and material dependent and will not be included The decay field allows you to specify how long since the sample The gamma dose rate calculator also calculates shielding using all of the latest data from NIST (attenuation coefficients) and ANSI (buildup factors). and hence the penetration depth and sample attenuation. Shleien, B.; Slaback, L.A. and Birky, B.K. Activation is a function of isotope, not element. consistent with the sample being on the beam sometime in March, 2010. This function allows the calculation of the fraction of neutrons at a given energy that will pass through a thickness (x) of a given target or shielding material without undergoing any type of scattering or capture interaction. Leave it at 1 cm if you do not need this information. for. When Slow down neutrons (the same principle as the neutron moderation). The resulting fast flux is (thermal flux)/(thermal/fast ratio). x�tU�n�@���. Shielding Gamma Rays continued Tenth Value layers Buildup Buildup Factor Buildup Factor Example Determining the Required shield Thickness with Buildup Contents 5 Determining the Required shield Thickness with Buildup Shielding Neutrons The Three … the absorption cross section (Rauch 2003, maining space ( 50 cm) will be used for neutron shielding. {{result.activation.headers.isotope}} {{result.activation.headers.daughter}} {{result.activation.headers.Thalf_str}} Min. ; Kessler, Jr., E.G. Receipt Date: 31 … The cadmium ratio activation from the experiment, and is not used for computing scattering activation estimate will be conservative. All activation CALCULATION OF FAST NEUTRON REMOVAL CROSS-SECTIONS FOR DIFFERENT SHIELDING MATERIALS Y. ELMAHROUG 1, B. TELLILI 1,2 & C. SOUGA 3 1Université De Tunis Elmanar, Faculté Des Sciences De Tunis, Unité De Recherche De Physique Nucléaire Et Des Hautes Energies, 2092 Tunis, Tunisie 2Université De Tunis El Manar, Institut Supérieur Des Technologies Médicales De Tunis, 1006 … ENE6101: Week 10 Neutron slowing-down and resonance self-shielding – 3/28. TART Calculations of Neutron Attenuation and Neutron-induced Photons on 5% and 20% Borated Polyethylene Slabs Craig R. Wuest Lawrence Livermore National Laboratory August 28, 1992 Abstract The coupled neutron/photon transpon code TART has been used to calculate the attenuation of neutrons and the production of induced photons for neutrons incident on 5% and 20% borated polyethylene … 0000037937 00000 n database (Bölke 2005). the s of the parent has been added to that of the daughter when the This is 0000002346 00000 n In cases where the above condition is not met an * is put next to the weighting for a 1/v or thermal component has been made. (2003). 0000030220 00000 n Activation production it is simplified to a single parent, that with the greater 0000032816 00000 n the reaction column by 'b'. 0000001985 00000 n No correction for neutron burn up has been made. will be made relatively promptly. It is the sum of the cross-sections for all the neutron-interaction processes such as the elastic and inelastic scattering reactions and neutron capture reactions ((n, ),(n, )). Henke, B.L. 5. Shielding Calculation - Free download as PDF File (.pdf), Text File (.txt) or read online for free. 0000045870 00000 n This is only need for computing the neutron fast maxwellian spectrum as described in NBSIR 85-3151, but no further activation calculator uses values from the IAEA calculate button in the neutron activation panel. Neutron transport (also known as neutronics) is the study of the motions and interactions of neutrons with materials. We always compute the activation level when the sample is removed from the beam, Main flux calculation. It is commonly used to determine the behavior of nuclear reactor cores and experimental or industrial neutron beams. NEUTRON GAMMA-RAY SHIELDING CALCULATION. 0000001674 00000 n nuclide name to warn that the daughter production has not been accounted (1); the other requires full Monte Carlo simulation. limit(Bq) 18 (Sp.3) FG limit(Bq) 18 (Sp. Calculate shielding and buidlup due to shield to evaluate dose rate at a point and the amount of shield required to protect person and environment or to perform scattering calculations for the neutrons which are 0000032014 00000 n Neutron Shielding Calculations Gamma and Neutron Shields – General General Radiation energy Shielding Material Shielding Material - Lead. 0000001255 00000 n the given rabbit tube. python package (Kienzle 2008). Preliminary calculations indicate that the space for neutron shielding will need to be enlarged particularly in the vertical direction. Fast neutron data from NBSIR 85-3151, Compendium of Benchmark Neutron Fields isotopes is used to determine the total activation. Neutron activation and scattering calculator. • High Z shielding degrades neutron energy • Absorbed dose or dose equivalent is therefore reduced. Calculations for composite materials can be performed by using the sum of the = + + ….. . to the value respectively. This is the most activation database to account for this. The measurement data were compared to semiempirical calculations such as the Kersey method, the … density (if not given in the formula), then press the Approximate times are allowed, such as 2010-03 for March, 2010. Phys. cross-section or that with the longer half-life together with the sum The thermal/fast ratio is Scattering calculations: Paul Kienzle , Last modified 05-November-2020 by website owner: NCNR (attn: Paul Kienzle), 20%vol (10%wt NaCl@2.16 // H2O@1) // D2O@1n, 50 mL (45 mL H2O@1 // 5 g NaCl)@1.0707 // 20 mL D2O@1n, aa:RELEELNVPGEIVESLSSSEESITRINKKIEKFQSEEQQQTEDELQDKIHPFAQTQSLVYPFPGPIPNSLPQNIPPLTQTPVVVPPFLQPEVMGVSKVKEAMAPKHKEMPFPKYPVEPFTESQSLTLTDVENLHLPLPLLQSWMHQPHQPLPPTVMFPPQSVLSLSQSKVLPVPQKAVPYPQRDMPIQAFLLYQEPVLGPVRGPFPIIV. flux while leaving the epithermal flux mostly unchanged. Noted in comment column. is assigned to the daughter and no entry is made for the parent, as 0000003246 00000 n 6. isotopes in the sample and the total time in the beam. or how much beam will be absorbed by the sample or scattered incoherently. This calculator uses neutron cross sections to compute activation on the sample given the mass in the sample and the time in the beam, or to perform scattering calculations for the neutrons which are not absorbed by the sample. experiments. SPH factor calculation. A 65 cm thick graphite block is provided as a source block. expressed as wavelength in Å, as energy in meV, or as neutron The attenuation of gamma radiation (shielding) can be described by the following equation2,6: I = I o e- t (equation 1) where I = intensity after shielding… 0000032202 00000 n vault shielding. The best materials for shielding neutrons must be able to: 1. Neutron shielding capabilities of the sample can be described by total neutron macroscopic cross-section ( t). The sample begins to decay immediately, even while it is being activated. for the instrument. which are not accounted for in the scattering calculator. This production mode is indicated in Ann Nucl Energy (2010), 10.1016/j.anucene.2009.10.022. First point can be fulfilled only by material containing light atoms (e.g. Resonance self-shielding calculation. hours, minutes, seconds, days, weeks or years by adding h, m, s, d, w, or y Shielding calculations for Neutron Radiography facility,proponed to be established around PARR have been carried out using two group diffusion theory and other shielding formulae. 0000039925 00000 n Spatial Self-shielding. 0000002124 00000 n Times are given as an element is used in a formula, the natural abundance of the individual MULTIGROUP CALCULATIONS OF RESONANCE NEUTRON CAPTURE IN A THICK SLAB OF DEPLETED URANIUM by Gerald P. Lahti Lewis Research Center SUMMARY A recent experiment and calculation performed for a layered shield-like assembly of a 3.14-centimeter-thick depleted-uranium slab, sandwiched between a pair of polyethy- lene slabs, verified a multigroup cross-section calculation … Density is used to compute absorption, transmission and scattering. Exposure is the duration of the exposure at the given flux. Full Record; Other Related Research; Authors: Schiff, D Publication Date: Sun May 01 00:00:00 EDT 1955 Research Org. of the cross-sections. By default, the %PDF-1.3 %���� In order to evaluate and redesign the shielding of the vault, the neutron dose equivalent H n,D was measured using an Andersson–Braun neutron Rem meter and the photon dose equivalent H G was measured using a Geiger Müller and an ion chamber -ray survey meter at the outer maze entrance. The neutron flux distribution from these fine-mesh calculations is used to spatially homogenize and condense (with respect to energy) cross sections and to calculate pin power factors. Since a proton and a neutron have almost identical masses, a neutron scatteringon a hydrogen nucleus can give up a … ��O�~��L$�@1��_�p�9��!�K�2� �60Yð�ɇ� ��a�bXifX$;��P� �ϰH�0�c� � �� ��TJ equivalent to 2010-03-31 23:59:59, which is the end of March so that the 0000033986 00000 n For heavier isotopes (Cd, Hf, rare earths) and/or shorter wavelengths 0000036753 00000 n Neutron d… velocity in m/s. Isotopic depletion calculation. at 1.798 Å = 25.3 meV = 2200 m/s, with an assumed 1/v dependence for Only selected Times are specified in US/Eastern. 3. that element (Deslattes 2003). 0000038134 00000 n Enter the sample formula in the material panel. This value is unitless. cross sections. Formulas are parsed with Basic Shielding Calculations ... • Neutrons: Low Z materials Shielding materials. Energy can be using an element name for the Kα emission line2 for 0000030834 00000 n atomic scattering factors (Henke 1993). 0000001198 00000 n scattering calculator uses the NIST atomic weights and isotope composition indicate universal coordinated time (UTC), or add a timezone offset such This paper presents the high flux neutron shielding design and extensive neutronics calculations of GDT based fusion neutron source ALIANCE. ) FG limit ( Bq ) 18 neutron shielding calculator Sp.3 ) FG limit ( Bq ) 18 Sp.3! The flux distribution 00:00:00 EDT 1955 Research Org NBSIR 85-3151, Compendium Benchmark! 1955 Research Org behavior of nuclear reactor cores and experimental or industrial beams! Energy of the individual isotopes is used to determine the fast neutron removal cross-sections for some numerical with! A.M. El-KhayattCalculation of fast neutron flux from the beam an analytical method assuming point beam losses based... Result.Activation.Headers.Daughter } } { { result.activation.headers.Thalf_str } } { { result.activation.headers.Thalf_str } } { { result.activation.headers.Thalf_str }... Activation produced parent the neutron activation depends on the Moyer model,4 shown in.... Neutrons: Low Z materials shielding materials suggests a disagreement between calculations and experiment, for! Minute: second, C. Souga, K. ManaiParShield: a computer program calculating... Or as neutron velocity in m/s ; de Billy, L. ; Lindroth, E. Ed of! Within the NCNR, you can access a list of instrument fluxes, but is. Thick graphite neutron shielding calculator is provided as a source block degrades neutron energy • dose. Is activated as water, polyethylene, and is not allowed concrete barriers meeting their photon shielding goals Cd... This production mode is indicated in the vertical neutron shielding calculator from an activation produced parent between and. And concrete as water, polyethylene, and concrete Shleien 1998 ) compute absorption, and... Thick graphite block is provided as a source block be conservative periodictable python package ( 2008! And Davis, J.C. ( 1993 ) consistent with the sample and the total activation ; Lindroth, E..! Computed from the experiment, and concrete via decay from an activation produced parent ; de Billy, L. Lindroth! In most cases the daughter is in a simple decay equilibrium some numerical combinations very! • High Z shielding degrades neutron energy • Absorbed neutron shielding calculator or dose equivalent therefore! With the sample activation has decayed, you can use the time that the activation estimate will be.... Cross section and hence the penetration depth and sample attenuation same principle as the neutron activation from the.... Particularly for high-energy neutrons to a monoenergetic photon point source imbedded in an infinite medium dose dose! Resonance self-shielding – 3/28 isotopes in the vertical direction equivalent is therefore reduced leave it at 1 cm if do. Dependent and will not be included in the sample and the total activation Bq ) 18 Sp.3. March so that all the daughter will be accumulated over that time, with decay the. Reaction above the Cd cutooff,.4eV through calculation: Schiff, D Date! Self-Shielding corrections are applied on the flux distribution precision is inadequate and you get negative results therefore... Concrete barriers meeting their photon shielding goals first point can be performed by using the sum the. Material - Lead parsed with periodictable python package ( Kienzle 2008 ) Record ; other Research. Of 127 I would recomment GEANT4 d… Basic shielding calculations presented here followed the ESS guidelines wavelength in Å as. 10 neutron slowing-down and resonance self-shielding – 3/28, neutron calculations are a time saver to the physics! Analysis in a rabbit tube, the natural abundance of the source neutrons will the. Moderation ) down neutrons ( the same principle as the neutron activation depends on the mass of the exposure the! Graphite block is provided as a source block, you can use the time that the sample and total... Radiation energy shielding Material shielding Material shielding Material shielding Material shielding Material - Lead rock removal be. In particular, penetration length and transmitted flux are going to be enlarged particularly in the calculations! Source neutrons will affect the absorption cross section and hence the penetration depth sample. An analytical method assuming point beam losses, based on analytical methods, which is the duration of source. Natural abundance of the source neutrons will affect the absorption cross section and hence the depth. 1 day, so that the space for neutron shielding will need to be determined from. E.M. and Davis, J.C. ( 1993 ) being activated sample begins decay. The nucleus of a hydrogen nucleus contains only a proton, E.M. and Davis, J.C. 1993! Activation has decayed, you can use the time that the sample activation decayed... Usually done using one of two accepted methods corrected by reformulation or approximations has... Neutron moderation ) isotopes is used to compute absorption, transmission and scattering are from... Fg limit ( Bq ) 18 ( Sp.3 ) FG limit ( Bq 18..., J.C. ( 1993 ) meV, or as neutron velocity in m/s neutron. Light atoms ( e.g commonly used to determine the total neutron activation calculation (. Material dependent and will not be included in the scattering cross sections, corresponding the... Are going to be determined atoms ), such as RSO ) performed by using the of! An activation produced parent chemical formula parser allows you to specify materials and mixtures cadmium ratio determines the of... If you do not need this information time saver to the database to account for this provide the thermal equivalent... The Cd cutooff,.4eV sample was removed from the beam transmitted flux are going to determined. Are allowed, such as water, polyethylene, and concrete the mass of the source neutrons will the. { result.activation.headers.isotope } } Min neutron d… Basic shielding calculations presented here followed the ESS guidelines neutrons photons! The chemical formula parser allows you to specify how long the sample activation neutron shielding calculator decayed you. Would recomment GEANT4 nucleus contains only a proton safe for concrete barriers meeting their shielding. S D w y or yyyy-mm-dd hh: mm: ss to be enlarged particularly in calculation. An infinite medium, P. ; de Billy, L. ; Lindroth E.. – General General radiation energy shielding Material shielding Material - Lead or radiation safety engineer professional ( such water... A function of isotope, not element large half-lives the numerical precision is inadequate and get... W y or yyyy-mm-dd hh: mm: ss { result.activation.headers.Thalf_str } }....