The photoproduction of the 93mMo nucleus on natural molybdenum was studied using the electron beam of the LUE-40 linac RDC “Accelerator” NSC KIPT. Measurements were performed using the activation method and off-line γ-ray spectrometric technique. For the natMo(γ,xn)93mMo reaction the experimental flux-averaged cross-sectionϭ(Eγmax)m at the bremsstrahlung end-point energy range of 38…93 MeV was first time determined. The theoretical values of the yields Ym,g(Eγmax) and flux-averaged cross-sections(Eγmax)m,g for the natMo(γ,xn)93m,gMo reactions were calculated using the cross-sections ϭ(Eγ) from the TALYS1.96 code for different gamma strength functions and level density models. The comparison showed strong discrepancies between the experimental values and the theoretical results of (Eγmax)m.

New detectors for future high-energy physics experiments will operate under unprecedented radiation dose rates. This condition requires improved radiation resistance on detector equipment. The consequent development of new materials, particularly optical materials, becomes crucial. In this work, optical components mean reflectors, light absorbers, or light transmitters. These materials, reflectors or light transmitters, are needed in detectors primarily to collect and transmit light from the scintillator to the PMT. When it comes to light absorbers, they are required to protect the detector from light from the environment. This work aims at studying selected optical materials with improved properties (functional and optical) and radiation resistance that can be used in new detectors at the Large Hadron Collider (LHC) experiments. Light transmittance, optical reflection, thermal characteristics, and radiation resistance were investigated to evaluate the proposed materials. We have developed optical systems based on siloxanes to continue our previous developments of radiation-resistant materials for radiation detectors. We also report a study of several reflective materials and light absorber introduced into the siloxane. Investigations have shown that these systems are radiation resistant to doses of at least 1 MGy. Tested samples were irradiated at linear electron accelerator LUE-40 in the National Science Center Kharkiv Institute of Physics and Technology (KIPT). The accelerated electrons were sent to the heavy complex targets to deliver the irradiation with gamma or neutron fluxes. The consequent gamma and neutron fluxes and doses were estimated with the GEANT4 simulation.

The photoproduction of ^95m Nb on ^natMo was studied using the electron beam of the LUE-40 linac RDC ”Accelerator” NSC KIPT. Measurements were performed using activation and off-line γ -ray spectrometric techniques. The experimental flux-averaged cross-section ⟨σ (E_γ max)⟩ _m for the ^natMo(γ ,xnp)^95m Nb reaction at the bremsstrahlung end-point energy range of 38–93 MeV has been first time obtained. The estimated values ⟨σ (E_γ max)⟩ _g for the formation of ^95 Nb in the ground state and total cross-sections ⟨σ (E_γ max)⟩ _tot for the studied reaction were determined. The theoretical values of the yields Y_m,g,tot(E_γ max) and flux-averaged cross-sections ⟨σ (E_γ max)⟩ _m,g,tot for the ^natMo(γ ,xnp)^95m,g,tot Nb reactions were calculated using the cross-sections σ (E) from the TALYS1.95 code for six different level density models. The comparison showed a significant excess of the experimental results over the theoretical ⟨σ (E_γ max)⟩ _m,g,tot values.

The photoproduction of the 93m Mo nucleus on natural molybdenum was studied using the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT. Measurements were performed using the activation method and offline y-ray spectrometric technique. For the nat Mo(gamma, x n) 93m Mo reaction the experimental flux-averaged cross-section (cs ( E ymax ) ) m at the bremsstrahlung end-point energy range of 38...93 MeV was first time determined. The theoretical values of the yields Y m,g ( E ymax ) and flux-averaged cross-sections (cs ( E ymax ) ) m,g for the nat Mo(gamma, x n) 93m,g Mo reactions were calculated using the cross-sections cs ( E gamma ) from the TALYS1.96 code for different gamma strength functions and level density models. The comparison showed strong discrepancies between the experimental values and the theoretical results of (cs ( E ymax ) ) m .

Production of the 55-57Co Co nuclei on nat Ni in photonuclear reactions using bremsstrahlung gamma photon irradiation with end-point energy E gamma max between 35 and 94 MeV has been studied. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT using the methods of gamma activation and off-line gamma-ray spectroscopy. The obtained experimental flux-averaged cross-sections (a ( E gamma max ) ) agree with the data found in the literature. The theoretical flux-averaged cross- sections (a ( E gamma max ) ) th for the production of 55-57Co Co and 55-57Ni Ni were estimated using the cross-section values a ( E ) from the TALYS1.95 code and bremsstrahlung spectra of gamma photons calculated by GEANT4.9.2. The experimental results for 56,57Co , 57 Co agree with the cumulative (a ( E gamma max ) ) th . For the reactions with the production of 55 Co nuclei, the theoretical values differ from experimental ones.

The results of photoproduction of isomeric pairs from the (γ,xn) and (γ,pxn) reactions on nuclei from Zr up to Ta at the bremsstrahlung end-point energy range 30…100 MeV are systematized. Measurements were performed at the electron beam of the LUE-40 linac RDC “Accelerator” NSC KIPT using the activation method and off-line γ-ray spectrometric technique. The theoretical isomeric ratios IR for the nuclei-products of studied reactions were calculated using the cross-sections σ(E) from the TALYS1.95 code for six different level density models. The data from the international databases were additionally used to compare experimental results and theoretical predictions. The obtained results let us make conclusions about trends of values and energy dependence of IR in studied photonuclear reactions. Further directions of experimental research in the RDC “Accelerator” NSC KIPT are discussed.

The production of the $$^{180\textrm{m}}\textrm{Hf}$$ 180 m Hf nuclei in the photoproton reaction $${^{181}\textrm{Ta}}(\gamma ,p)$$ 181 Ta ( γ , p ) was studied at end-point bremsstrahlung energies $$E_{\mathrm{\gamma max}}=35$$ E γ max = 35 –95 MeV. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the $$\gamma $$ γ activation and off-line $$\gamma $$ γ -ray spectroscopy. The experimental values of the bremsstrahlung flux-averaged cross-sections $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{m}}$$ ⟨ σ ( E γ max ) ⟩ m for the $${^{181}\textrm{Ta}}(\gamma ,p)^{180\textrm{m}}\textrm{Hf}$$ 181 Ta ( γ , p ) 180 m Hf reaction were determined, and at $$E_{\mathrm{\gamma max}} > 55$$ E γ max > 55 MeV obtained for the first time. The measured values, as well as the literature data, significantly (by more that an order of magnitude) exceed the theoretical flux-averaged cross-sections $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{th}}$$ ⟨ σ ( E γ max ) ⟩ th . The $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{th}}$$ ⟨ σ ( E γ max ) ⟩ th values were calculated using the cross-section $$\sigma (E)$$ σ ( E ) computed with the TALYS1.95 code for six different level density models. A comparative analysis of the calculated total cross-sections from the TALYS computation for the reactions $${^{181}\textrm{Ta}}(\gamma ,p)^{180}\textrm{Hf}$$ 181 Ta ( γ , p ) 180 Hf and $${^{181}\textrm{Ta}}(\gamma ,n)^{180}\textrm{Ta}$$ 181 Ta ( γ , n ) 180 Ta was performed. It was shown that the photoproton $$(\gamma ,p)$$ ( γ , p ) to photoneutron $$(\gamma ,n)$$ ( γ , n ) strength ratio is consistent with the estimates based on the isospin selection rules and the value from the $$(e,e'p)$$ ( e , e ′ p ) experiment.

The Mo-nat(gamma , xnp)(95m;g )photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40. The experiment was performed using the activation and off-line gamma-ray spectrometric technique. The experimental isomeric yield ratio (IR) was determined for the reaction products (95) (m,g ) Nb at the bremsstrahlung end-point energy E gamma(max )range of 38-93 MeV. The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data. The theoretical values of the yields and the IR for the isomeric pair (95) (m,g ) Nb from the Mo-nat(gamma , xnp) reaction were calculated using the partial cross-sections from the TALYS1.95 code for six different level density models. For the investigated range of E gamma(max), the theoretical dependence of IR on energy was confirmed - the IR smoothly increases with increasing energy. The comparison showed a noticeable difference (more than 3.85 times) in the experimental IR relative to all theoretical estimates.

The ^ natMo(γ,x np)^95 m,gNb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40. Experiment was performed using the activation and off-line γ-ray spectrometric technique. The experimental isomeric yield ratio d(E_γ max) = Y_ m(E_γ max) / Y_ g(E_γ max) was determined for the reaction products ^95 m,gNb at the end-point bremsstrahlung energy E_γ max range of 35-95 MeV. The obtained values of d(E_γ max) are in satisfactory agreement with the results of other authors and extend the range of previously known data. The theoretical values of the yields Y_ m,g(E_γ max) and the isomeric yield ratio d(E_γ max) for the isomeric pair ^95 m,gNb from the ^ natMo(γ,x np) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models LD. The comparison showed a noticeable excess (more than 3.85 times) of the experimental isomeric yield ratio over all theoretical estimates. At the investigated range of E_γ max the theoretical dependence of d(E_γ max) on energy was confirmed - the isomeric yield ratio smoothly decreases with increasing energy.

The production of the ^180mHf nuclei in the photoproton reaction ^181Ta(γ ,p) was studied at end-point bremsstrahlung energies E_γ max=35 –95 MeV. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the γ activation and off-line γ -ray spectroscopy. The experimental values of the bremsstrahlung flux-averaged cross-sections ⟨σ (E_γ max)⟩ _m for the ^181Ta(γ ,p)^180mHf reaction were determined, and at E_γ max > 55 MeV obtained for the first time. The measured values, as well as the literature data, significantly (by more that an order of magnitude) exceed the theoretical flux-averaged cross-sections ⟨σ (E_γ max)⟩ _th . The ⟨σ (E_γ max)⟩ _th values were calculated using the cross-section σ (E) computed with the TALYS1.95 code for six different level density models. A comparative analysis of the calculated total cross-sections from the TALYS computation for the reactions ^181Ta(γ ,p)^180Hf and ^181Ta(γ ,n)^180Ta was performed. It was shown that the photoproton (γ ,p) to photoneutron (γ ,n) strength ratio is consistent with the estimates based on the isospin selection rules and the value from the (e,e'p) experiment.

AbstractThe production of the $$^{180\textrm{m}}\textrm{Hf}$$ 180 m Hf nuclei in the photoproton reaction $${^{181}\textrm{Ta}}(\gamma ,p)$$ 181 Ta ( γ , p ) was studied at end-point bremsstrahlung energies $$E_{\mathrm{\gamma max}}=35$$ E γ max = 35 –95 MeV. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the $$\gamma $$ γ activation and off-line $$\gamma $$ γ -ray spectroscopy. The experimental values of the bremsstrahlung flux-averaged cross-sections $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{m}}$$ ⟨ σ ( E γ max ) ⟩ m for the $${^{181}\textrm{Ta}}(\gamma ,p)^{180\textrm{m}}\textrm{Hf}$$ 181 Ta ( γ , p ) 180 m Hf reaction were determined, and at $$E_{\mathrm{\gamma max}} > 55$$ E γ max > 55 MeV obtained for the first time. The measured values, as well as the literature data, significantly (by more that an order of magnitude) exceed the theoretical flux-averaged cross-sections $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{th}}$$ ⟨ σ ( E γ max ) ⟩ th . The $$\langle {\sigma (E_{\mathrm{\gamma max}})}\rangle _{\textrm{th}}$$ ⟨ σ ( E γ max ) ⟩ th values were calculated using the cross-section $$\sigma (E)$$ σ ( E ) computed with the TALYS1.95 code for six different level density models. A comparative analysis of the calculated total cross-sections from the TALYS computation for the reactions $${^{181}\textrm{Ta}}(\gamma ,p)^{180}\textrm{Hf}$$ 181 Ta ( γ , p ) 180 Hf and $${^{181}\textrm{Ta}}(\gamma ,n)^{180}\textrm{Ta}$$ 181 Ta ( γ , n ) 180 Ta was performed. It was shown that the photoproton $$(\gamma ,p)$$ ( γ , p ) to photoneutron $$(\gamma ,n)$$ ( γ , n ) strength ratio is consistent with the estimates based on the isospin selection rules and the value from the $$(e,e'p)$$ ( e , e ′ p ) experiment.

A photoneutrons source based on the NSC KIPT LUE-40 electron linac was designed and constructed to study the effect of neutron and gamma radiation on the properties of materials used in high-energy physics (HEP) detectors. The source was used to irradiate the optical elements of the PLUME detector in LHCb experiment with the neutron fluency of 1014 cm-2. Ways to increase the neutron yield, in particular, by installing an additional high Z metal shell are shown. At electron energy of 85 MeV, the neutron yield exceeds 10-2 neutron over one electron.

The total bremsstrahlung flux-averaged cross sections (cr(E gamma max)) for the photonuclear reactions 181Ta(gamma , xn; x 8)181-xTa have been measured in the range of end-point energies E gamma maxup to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and offline gamma-ray spectrometric technique. The calculation of average cross sections was carried out using the cross section values computed with the TALYS1.95 code for different level density models LD 1-6. A comparison between the experimental total cross sections (cr(E gamma max)) and the theoretical values has shown satisfactory agreement for the 181Ta(gamma , xn) reactions with the escape of 1-7 neutrons.

The total bremsstrahlung flux-averaged cross-sections σ(Еmax) for the photonuclear reactions Ni(γ,xn)Ni and Ni(γ,xn)Ni have been measured in the range of end-point energies Еγmax = 35...94 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and off-line γ-ray spectrometric technique. The calculation of the flux-average cross-sections σ(Еmax)th was carried out using the partial cross-section values σ(Е) computed with the TALYS1.95 code and bremsstrahlung γ-flux calculated by GEANT4.9.2. The experimental results are compared with theoretical calculations and data from the literature. The obtained σ(Еmax) values expand the energy range of previously known experimental data. PACS: 25.20.-x, 27.40.+z

The bremsstrahlung of accelerated electrons passing through a converter is used to study multiparticle photonuclear reactions. The results of calculations, numerical modeling, design, and testing of a special magnetic cleaning system to obtain a "pure" beam of bremsstrahlung quanta when studying the cross-sections of such reactions at the LUE-40 linac are presented. The system is based on commercially available permanent magnets of rectangular cross-sections. The maximum on-axis field is 0.9 T, which provides sufficient separation of the electron beam and gamma rays at a distance of more than 90 mm from the magnet.

The bremsstrahlung flux-averaged cross-sections and the cross-sections per equivalent photon were first measured for the photonuclear multichannel reaction Al-27(gamma,x)Na-22 at end-point bremsstrahlung gamma energies ranging from 35 MeV to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 using the gamma-activation technique. The bremsstrahlung quantum flux was calculated with the GEANT4.9.2 program and was also monitored via the Mo-100(gamma, n)Mo-99 reaction. The flux-averaged cross-sections were calculated using the partial cross-section sigma(E) values computed with the TALYS1.95 code for different level density models. Consideration is given to special features of calculating the cross-sections and for the case of the final nucleus Na-22 via several partial channels x: n alpha + dt + npt + 2n(3)He + n2d + 2npd + 2p3n.

In experiments on the electron linac LUE-40 of RDC “Accelerator” NSC KIPT, the flux-averaged cross-sections σ(Еγmax)exp of photonuclear reactions 100Mo(γ,n)99Mo, 27Al(γ,x) 24Na, 93Nb(γ,n)92mNb, 93Nb(γ,3n)90Nb, and 181Ta(γ,n)180gTa were measured using the γ-activation technique. The theoretical flux-average cross-sections σ(Еmax)th were computed using the partial cross-section σ(Е) values from the TALYS1.9-1.95 codes and bremsstrahlung γ-flux calculated using GEANT4.9.2. Two different experimental setups were used in the experiments: an aluminum electron absorber and a deflecting magnet to clean the bremsstrahlung γ-flux from electrons. A comparison of the flux-average cross-sections measured for two experimental setups was performed. The possibility of using the reactions 100Mo(γ,n)99Mo,27Al(γ,x)24Na, 93Nb(γ,n)92mNb, 93Nb(γ,3n)90Nb, and 181Ta(,n)180gTa as monitors of the bremsstrahlung γ-flux for the energy range 30…100 MeV was investigated.

The total bremsstrahlung flux-averaged cross sections $\ensuremath{\langle}\ensuremath{\sigma}({E}_{\ensuremath{\gamma}\mathrm{max}})\ensuremath{\rangle}$ for the photonuclear reactions $^{181}\mathrm{Ta}{(\ensuremath{\gamma},xn;x\ensuremath{\le}8)}^{181\ensuremath{-}x}\mathrm{Ta}$ have been measured in the range of end-point energies ${E}_{\ensuremath{\gamma}\mathrm{max}}$ up to 95 MeV. The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the activation and offline $\ensuremath{\gamma}$-ray spectrometric technique. The calculation of average cross sections was carried out using the cross section values computed with the talys1.95 code for different level density models $LD$ 1--6. A comparison between the experimental total cross sections $\ensuremath{\langle}\ensuremath{\sigma}({E}_{\ensuremath{\gamma}\mathrm{max}})\ensuremath{\rangle}$ and the theoretical values has shown satisfactory agreement for the $^{181}\mathrm{Ta}(\ensuremath{\gamma},xn)$ reactions with the escape of 1--7 neutrons.

We present design and simulation results on the electron source for S-band technological electron linac. This device is a combination of an RF gun and a DC diode gun. The gun consists of a thermionic cathode, which is mounted on the wall of the TM010 cavity that is under negative high voltage potential relatively to an anode. The particles dynamics has been studied by simulation. At an average particle energy of 95 keV, the beam pulse current is 0.44 A, the emittance does not exceed 4.8 mmmrad, and 70% of all electrons are concentrated in the 72° phase range.