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SUMMARY:Mathematical modeling of thermal loads of x-ray  adaptive optics m
 aterials
DTSTART;VALUE=DATE-TIME:20200713T143200Z
DTEND;VALUE=DATE-TIME:20200713T143300Z
DTSTAMP;VALUE=DATE-TIME:20261008T193319Z
UID:indico-contribution-1884@indico.inp.nsk.su
DESCRIPTION:Speakers: Maksim Korobenkov (Immanuel Kant Baltic Federal Univ
 ersity)\nThe paper presents the results of a study of the thermal loads of
  materials used in the production of x-ray optics. The development of new 
 types of x-ray studies and the transition to the fourth generation of sync
 hrotron radiation sources\, which is realized by reducing the emittance of
  undulator sections\, requires advanced studies of the thermal stability o
 f the first components of the optical line of the beam. An increase in the
  radiation power density is a critical problem for the design of the optic
 al elements of the undulator section\; this is especially important for cr
 ystalline monochromators with relatively high angles of incidence. However
 \, other optical elements — windows\, lenses\, slits\, and zoom — are 
 exposed to thermal loads. Therefore\, it is important to consider the effe
 ct of thermal loads on materials of adaptive x-ray optics to predict not o
 nly cooling modes\, but also thermal deformations. To this end\, studies h
 ave been conducted on the interaction of X-rays with the main materials us
 ed in the production of X-ray optics - aluminum\, beryllium\, diamond and 
 UHMW (ultra high molecular weight polyethylene).\nThe occurrence of therma
 l gradients occurs due to the absorption of X-rays by the surface of the m
 aterial (radiant heat transfer) and volume absorption (according to the Bu
 rer-Lambert law). The problem was solved numerically by the finite element
  method in the ANSYS Workbench software package. In the framework of the t
 ask\, the heat flux arising from the interaction of X-ray radiation with t
 he surface of the substance was set as the boundary condition of heat tran
 sfer of the second kind. The shape of the heat spot was chosen in the form
  of a circle with a Gaussian character distribution of the density of ther
 mal radiation. The interaction of X-rays with a plate of finite size and t
 hickness was considered. As part of the problem statement\, 3 loading mode
 s with a characteristic X-ray wavelength were selected: 1\, 0.5\, and 0.25
  angstroms.\nThe results of the calculations showed that the use of UHMW a
 s a material for x-ray optics requires a very careful selection of operati
 ng modes\, preference should be given to modes with a very low power densi
 ty of the radiation load. The main heat load is associated with the surfac
 e absorption capacity of the material\, combined with low thermal conducti
 vity\, leading to the appearance of a surface heat source that can literal
 ly burn through the material.\nThe best calculated thermal stability resul
 ts were shown by diamond plates. In addition to excellent thermal conducti
 vity\, diamond has a low coefficient of volume attenuation of intensity\, 
 leading to low temperature gradients of the established temperature regime
 .\n\nhttps://indico.inp.nsk.su/event/24/contributions/1884/
LOCATION:
URL:https://indico.inp.nsk.su/event/24/contributions/1884/
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