Compton scattering and the MacKenzie spectrometer

1989 ◽  
Vol 67 (8) ◽  
pp. 798-805 ◽  
Author(s):  
Brian G. Williams
Keyword(s):  
Raman Scattering ◽  
Compton Scattering ◽  
Alternative Systems ◽  
Γ Ray ◽  
Fluorescence Spectrometer

The development of the MacKenzie γ-ray Compton scattering spectrometer is discussed in the context of earlier designs to bring out the advantages that it offers over alternative systems. The importance of the new spectrometer in providing the first accurate measurements of γ-ray Raman scattering and the role of Innes MacKenzie in the discovery of γ -ray Raman scattering are discussed. Finally, the potential of the MacKenzie spectrometer design to provide a field fluorescence spectrometer for use in geophysics is described.

scholarly journals Simple Modeling of the Ratio of Fields at a Tip and a Contacting Surface with External Illumination

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
E. Bortchagovsky
Keyword(s):  
External Field ◽  
Raman Scattering ◽  
External Excitation ◽  
Exciting Field ◽  
Rayleigh Approximation ◽  
Surface Configuration ◽  
Standard Configuration ◽  
Enhanced Raman Scattering ◽  
Simple Modeling

The analysis of the relation of fields generated at a tip and a contacting surface is performed in the Rayleigh approximation of a simple dipole model for the standard configuration of tip-enhanced Raman scattering experiments with external excitation. A comparison of the present results with the previous ones obtained for the case of tip-source reveals the role of tip-surface configuration as the amplifier of the exciting field and the stronger influence of roughness on the field distribution at external illumination, as roughness is directly excited by the external field producing second source of field in addition to the tip.

A new design for a γ -ray Compton scattering spectrometer

1985 ◽  
Vol 398 (1815) ◽  
pp. 405-414 ◽  
Keyword(s):  
Single Crystals ◽  
Compton Scattering ◽  
Small Samples ◽  
Compton Profile ◽  
Accurate Data ◽  
Annular Geometry ◽  
Γ Rays ◽  
Γ Ray

A new design for a γ-ray Compton scattering spectrometer is presented. The spectrometer uses an annular geometry that is the inversion of the annular geometry used in earlier experiments with americium γ-rays. A small source is placed directly in front of the detector so that it is the detector and not the source that provides the annulus. Measurements of the Compton profile of aluminium are used to evaluate the new design. For small samples it is possible to increase the intensity by a factor of up to 10 4 while maintaining the resolution. This should make it possible to obtain accurate data for many compounds that could not previously be studied because of the difficulties associated with obtaining large single crystals.

The role of the UL41 gene of herpes simplex virus type 1 in evasion of non-specific host defence mechanisms during primary infection

Microbiology ◽  
2000 ◽  
Vol 81 (7) ◽  
pp. 1763-1771 ◽  
Author(s):  
Tatsuo Suzutani ◽  
Masayoshi Nagamine ◽  
Taiichiro Shibaki ◽  
Masahiro Ogasawara ◽  
Itsuro Yoshida ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Replication ◽  
Primary Infection ◽  
Interferon Α ◽  
Defence Mechanisms ◽  
Specific Host ◽  
Γ Ray ◽  
Simplex Virus

The UL41 gene product (vhs) of herpes simplex virus (HSV) is packaged in the virion, and mediates host protein synthesis shutoff at the early stage of the virus replication cycle. In order to clarify the role of vhs in virus replication and virulence, we isolated a completely UL41-deficient mutant (the VRΔ41 strain) and its revertant (the VRΔ41R strain). In the mouse encephalitis model, the replication of strain VRΔ41 was inhibited after 2 days post-infection, resulting in low virulence, by γ-ray-sensitive cells such as lymphocytes and/or neutrophils. The result suggested that some cytokines, produced in VRΔ41-inoculated brains, activate and induce the migration of γ-ray-sensitive cells to the infection site. Therefore, cytokines produced by HSV-1-infected human cells were screened, and potent inductions of interleukin (IL)-1β, IL-8 and macrophage inflammatory protein-1α by VRΔ41 infection were observed. Moreover, the VRΔ41 strain showed 20- and 5-fold higher sensitivity to interferon-α and -β compared to the wild-type strain, respectively. These results indicate that one important role of vhs in vivo is evasion from non-specific host defence mechanisms during primary infection through suppression of cytokine production in HSV-infected cells and reduction of the anti-HSV activity of interferon-α and -β.

Sign in / Sign up

Export Citation Format

Share Document