• A.S. Aryshev, S. Araki, M.K. Fukuda, J. Urakawa
  KEK, Ibaraki
• V. Karataev
  JAI, Egham, Surrey
• G.A. Naumenko
  INPR, Tomsk
• A. Potylitsyn, L.G. Sukhikh, D. Verigin
  TPU, Tomsk
• K. Sakaue
  RISE, Tokyo

High-bright­ness and re­li­able sources in the VUV and the soft X-ray re­gion may be used for nu­mer­ous ap­pli­ca­tions in such areas as medicine, bi­ol­o­gy, bio­chem­istry, ma­te­ri­al sci­ence, etc. 4th gen­er­a­tion light sources based on X-ray free elec­tron lasers are being built in a few world's lead­ing lab­o­ra­to­ries. How­ev­er, those in­stal­la­tions are very ex­pen­sive and the ac­cess to wider com­mu­ni­ty is very lim­it­ed. We pro­pose a new ap­proach to pro­duce the in­tense beams of X-rays in the range of less than 500 eV based on com­pact elec­tron ac­cel­er­a­tor. An ul­ti­mate goal of the pro­ject is to cre­ate a com­pact soft X-ray source based on Thom­son scat­ter­ing of Co­her­ent Diffrac­tion Ra­di­a­tion (CDR) using a small ac­cel­er­a­tor ma­chine. CDR is gen­er­at­ed when a charged par­ti­cle moves in the vicin­i­ty of an ob­sta­cle. The ra­di­a­tion is co­her­ent when its wave­length is com­pa­ra­ble to or longer than the bunch length. The CDR waves will be gen­er­at­ed in an opened res­onator formed by two mir­rors. In this re­port we rep­re­sent the sta­tus of the ex­per­i­ment. The pilot ex­per­i­men­tal re­sults and gen­er­al hard­ware de­sign will be demon­strat­ed.

• A. Potylitsyn, S.Yu. Gogolev, D.V. Karlovets, Yu.A. Popov, L.G. Sukhikh
  TPU, Tomsk
• G.A. Naumenko, M.V. Shevelev
  Tomsk Polytechnic University, Nuclear Physics Institute, Tomsk

A non­in­va­sive tech­nique to de­ter­mine a sub-mm length of elec­tron bunch­es (rms < 100 um) based on a mea­sure­ment of the co­her­ent Cherenkov ra­di­a­tion (CChR) spec­trum in THz range is pro­posed. CChR is gen­er­at­ed when elec­tron bunch moves in a vac­u­um near di­elec­tric tar­get. If the op­ti­cal prop­er­ties and ge­om­e­try of a tar­get are cho­sen in order to achieve a low ab­sorp­tion with a dis­per­sion al­low­ing ex­pand­ing the Cherenkov cone, such tar­get may be con­sid­ered as the «nat­u­ral Cherenkov prism». We demon­strat­ed a fea­si­bil­i­ty of using of CsI prism for mea­sure­ment of a bunch length in the range 50-200 um for Lorentz fac­tor = 100. We also mea­sured CChR power from Teflon tar­get gen­er­at­ed by the 6.1 MeV bunched elec­tron beam with bunch rms length 1.2 mm and com­pared it with co­her­ent diffrac­tion ra­di­a­tion one for iden­ti­cal con­di­tions. CChR seems to be a promis­ing ra­di­a­tion mech­a­nism for a new beam di­ag­nos­tics tech­nique.