Iranian Light Source Facility Research Articles

Comparison of two vacuum system technologies for the synchrotron storage ring: case study of Iranian Light Source Facility

The current study compares two vacuum system designs for the Iranian Light Source Facility (ILSF) storage ring: conventional vacuum system design with stainless-steel vacuum chambers that are pumped by Non-Evaporable Getter (NEG) cartridges and ion pumps. In this design, all synchrotron radiation is absorbed by the local photon absorbers. In the second design, the water-cooled copper tubes that are coated with NEG materials are used as the vacuum chambers. This study will illustrate the advantages of using the NEG-coated vacuum chambers over the conventional design with the stainless-steel chambers. Since the two designs for ILSF are now completed, some of the details of this comparison might be interesting to other light sources, especially those that have plans to upgrade to a 4th generation.

Conceptual design of a super bend dipole magnet as a high-field source for the ILSF storage ring

The Iranian Light Source Facility (ILSF) is in the detailed design phase. It will operate at 3 GeV and 400 mA with an ultra-low horizontal emittance of 0.27 nm.rad. The main storage ring combined dipole magnet has a 0.56 T magnetic field and a -7 T/m gradient. It can serve as a soft X-ray source. There are several ways to achieve hard X-rays; one is to use a high-field dipole. It is designed with a permanent magnet and consists of three parts; a high field part that provides a 3 T magnetic field and two low field parts on either side of the high field one. The basic design of the super-bend dipole magnet is presented here.

Conceptual design of multipole injection kicker magnets for the ILSF storage ring

The standard injection scheme of the Iranian Light Source Facility(ILSF) is composed of 2 septum and 4 kicker magnets installed in a 7-meter-long straight section. Further tuning of the 4 kicker devices to reduce perturbations has proven to be almost impossible since it requires having 4 identical magnets, electronics and Ti-coated ceramic chambers. Different from pulsed dipole kicker magnets used in a conventional local-bump injection, a single nonlinear or multipole kicker provides a nonlinear distribution of magnetic fields, which has a maximum value off the axis where the injected beam arrives and a zero or near-zero value at the center where the stored beam passes by. So, here the designs of different multipole kickers, including sextupole, octupole and a nonlinear kicker, have been investigated and compared.

Shielding design aspects of SR in 3 GeV ILSF

Iranian Light Source Facility (ILSF) is an under-construction synchrotron radiation accelerator consisting of a 150 MeV linac, a booster synchrotron operating from 150 MeV to 3 GeV, and a 3 GeV storage ring that stores a maximum of 400 mA current of electrons. As the stored beam circulates, a fraction of the beam is lost due to interactions with gas molecules, interactions among beam particles, and orbital bending, which produce radiation. The bulk shielding calculation for the ILSF and the input parameters used for this analysis are discussed in this paper. The potential of skyshine neutrons to cause radiation hazards is investigated as well. Moreover, the design and shielding simulation using the FLUKA Monte Carlo code is presented for the linac beam stop and primary and scattered gas bremsstrahlung for the first optics enclosure of the ILSF spectro microscopy beamline. Our designed radiation shielding system guarantees that the annual dose in all areas around the ILSF machine does not exceed the dose limit of 1 mSv.

A new design for the RF electron gun of the Iranian Light Source Facility (ILSF)

A new π mode RF electron gun is proposed for the Iranian Light Source Facility. This RF gun will be fabricated using a newly developed method based on clamping the parts together instead of vacuum brazing. In this method, RF contact and vacuum seal are mutually provided by a special copper gasket. The first section of this article describes the new π mode RF gun and its expected performance in detail. The report of our recent R&D tests on the new fabrication method is discussed in the next section. We performed the RF and vacuum measurements on a single-cell structure, and the copper gasket provided suitable RF contact, and a vacuum pressure of 2.5×10−7 mbar was also reached after 1 h of pumping with a turbo-molecular pump without baking. In the last section, we investigated using a high-current and low-emittance DC triode electron gun to be mounted on the RF gun as an alternative cathode assembly. The simulation results of this proposed scheme were compatible with our previous studies. The research and development of the new π mode RF electron gun and the proposed cathode assembly will begin soon.

Magnetic cross-talk simulation for Iranian Light Source Facility storage ring

Magnetic cross-talk due to the small free space between the magnets of a machine may result in significant distortions of the magnetic field integration and performance distortion of the machine. This paper presents the preparation done at the Iranian Light Source Facility (ILSF) on integrated magnetic components of three storage ring (SR) magnets with minimum space between the yokes, modeled separately in Opera-3D code and accumulatively as in the lattice design. The results show that the integrated quadrupole component of the BE2 dipole magnet remains nearly the same, while the integrated dipole and sextupole components are reduced by 0.13% and 4.69%, respectively. By the same token, the integrated quadrupole component of the Q11 in the lattice is decreased by 0.07%, and the integrated sextupole component of the S4 sextupole is reduced by 8.14%. The probable deviation on the higher-order integrated multipoles together with harmonic fields along the beam trajectory are discussed, and some studies are introduced to cut down any deficient effects.

Design of low emittance booster ring magnets for Iranian Light Source Facility[This paper is supported by Iranian Light Source Facility.

Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation laboratory in the detailed design stage. The main building site is being excavated in Qazvin, 150 km from Tehran. The Booster ring of this facility with a circumference of 504 m and a low emittance of 3.5 nm rad accelerates electrons from 150 MeV to 3 GeV. Using POISSON and OPERA codes, we designed the ILSF booster ring magnets including dipoles, quadrupoles, sextupoles, and separate correctors. Cooling and electrical calculations are done, and ramping effects are considered. The ILSF has also been attempting to practice mechanical designs and to build prototype magnets at this stage too.

Study and Design of the Appropriate High-Performance Computing System for Beamline Data Analysis Application at Iranian Light Source Facility (ILSF)

Study and Design of the Appropriate High-Performance Computing System for Beamline Data Analysis Application at Iranian Light Source Facility (ILSF)

Design of 100 MHz RF cavity for the storage ring of the Iranian Light Source Facility (ILSF)

The Iranian Light Source Facility is a fourth-generation low emittance synchrotron light source under development in Iran. The design and in-house fabrication of RF cavities are key elements of this project. The choice of 100 MHz capacity loaded RF cavities offers many advantages compared to other cavity types due to a simpler geometry, ease of fabrication, and lower costs for manufacturing and RF power system development. Here we present comprehensive simulation studies of these accelerating RF cavities. This includes electromagnetic, mechanical, and thermal calculations. In addition, in the electromagnetic design section, discussions of higher-order modes, their impact on beam instabilities during machine operation and beam loading effects are addressed. Finally, thermomechanical simulation results are presented. The fabrication of a 100 MHz capacity-loaded cavity has started based on the design presented in this article.

Magnet design for Iranian Light Source Facility storage ring

The Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation laboratory which is in the detailed design stage and the main building site is being excavated in Qazvin, 150 km from Tehran. The ILSF storage ring (SR) is based on a Five-Bend Achromat (5BA) lattice providing an ultra-low beam emittance of 270 pm rad. The ring is comprised of 100 combined dipole magnets, 240 quadrupoles and 320 sextupoles with additional coils as dipole and skew quadrupole correctors. In this paper, some design features of the SR magnets along with their detailed physical design are debated. The corresponding electrical and cooling calculations and mechanical layouts are investigated as well.

Magnetic design of a new source for bending magnet beamlines at ultra-low emittance ILSF ring

The Iranian Light Source Facility (ILSF) is a 3-GeV third-generation synchrotron radiation laboratory in the basic design phase. The storage ring (SR) is based on a five-bend achromat (5BA) lattice, which provides ultra-low horizontal emittance of 0.27 nm rad. It is recommended to use short-length wigglers for hard x-ray generation because of the ILSF storage ring straight section limitations. This article describes the magnetic design and optimization of the three-pole wiggler and its beam dynamics effects on the SR lattice that have been investigated for the ILSF. The 3D modeling and flux calculations have been carried out by the Radia, SPECTRA and SRW Codes.

MOGA optimization for the ILSF low-beta lattice storage ring

In this paper, The Multi-Objective Genetic Algorithm (MOGA) is employed to optimize a low-beta lattice for the storage ring of the Iranian Light Source Facility (ILSF) [1]. This technique is based on tracking particles to select the working tune points and the appropriate sextupoles strengths, which in turn improve Dynamic Aperture (DA) and Momentum Acceptance (MA) . In addition, we utilize Frequency Map (FMA) and tune scan to optimize MOGA results. Furthermore, the effect of multiple errors due to magnetic elements and Insertion Device (ID) is studied in the ILSF storage ring and the details of beam parameter variation because of the errors and an in-vacuum undulator are discussed. The results show that by applying the MOGA, DA and Toscheck lifetime improve.

Vacuum system design for the storage ring of Iranian Light Source Facility

The current study describes the vacuum system of ILSF storage ring. The design uses the stainless steel vacuum chambers with a continuing keyhole profile all around the storage ring. The NEG cartridge and Ion pumps which are installed in the antechamber will pump all the vacuum sectors. Using Monte-Carlo simulation proved that the machine could reach an average pressure of 1 nTorr after the commissioning phase, which could guarantee a vacuum life time of about 13 h. The general layout of the vacuum system and the construction steps for the vacuum chambers will also be elaborated on. Several discrete photon absorbers which are designed in three types will absorb all the synchrotron radiations. For the heat load study, a simulation with Synrad is performed to calculate the power distribution on the absorber surfaces. Then the result is used to calculate the stress and strain on the absorbers by Finite Element Analysis (FEA).

Linear optics and coupling correction of ILSF storage ring lattice

The Iranian Light Source Facility (ILSF) is a 3 GeV synchrotron radiation facility, which is in the design stage. The ILSF storage ring design is based on a five-bend achromat lattice providing an ultralow horizontal beam emittance of 0.27 nm-rad. Inevitable errors like imperfection of magnetic field and misalignment of magnets will introduce various destructive effects on the performance of the machine. The possibility of correcting the errors should be thoroughly examined before settling the design. In this paper, we have tried to estimate the errors as realistic as possible based on the results obtained from the simulation of the elements and the accuracy of the predicted equipment for fabrication and alignment. The influence of errors on the lattice is investigated. Closed orbit distortion, beta beating and betatron coupling are corrected and improvement made in the lattice functions and machine performance will be presented.

Beam dynamics of high chromaticity lattice for Iranian light source facility (ILSF) storage ring

One of the limiting factors of electron beam lifetime in low emittance storage rings is Head-Tail (HT) instability. Low emittance storage rings typically have a large negative natural chromaticity due to the strong quadrupoles. Above transition large negative natural chromaticity leads to large Head-Tail instability which limit the beam lifetime. Since the threshold current of HT instability is directly related to linear chromaticity, increasing the linear chromaticity to slightly positive value is a solution to prevent HT instability. In this paper we in-creased the chromaticity of Iranian Light Source Facility (ILSF) to (+4, +4) and we will investigate the beam dynamics of ILSF 3GeV storage ring in high chromaticity. For reaching this aim we have used two families of sextupoles for chromaticity correction and then optimized them to maximize the dynamic aperture and Touschek lifetime. The beam dynamics of high chromaticity lattice is presented in this paper.

Behaviour analysis of a capacitive loaded RF cavity for the Iranian Light Source Facility (ILSF)

Synchrotron radiation has numerous applications in science and technology and is considered as one of the most significant research facilities required in Iran in the next 10 years. A key part in each synchrotron machine is its RF cavity. Improving the operation characteristics of the RF cavity will result in radiation quality enhancements. The cavity structure should be designed in a way that not only it can maintain the beam energy to the desired value, but also minimizes the collective instabilities on the beam. The development of the 100 MHz capacitive loaded RF cavity for the Iranian Light Source Facility was initiated in 2016. The main idea was to design a simple structure avoiding complicated fabrication technologies and to put more focus on applying different methods to control and also to minimize the effect of higher order frequency modes. Before engaging in fabrication of the main copper cavity, it was decided to manufacture a smaller aluminum cavity prototype in order to verify our simulations and moreover, improve the measurement methods and investigate the characteristics of the higher order frequency modes. In this paper, the design, simulations, and measurement results of this aluminum cavity prototype is described, two different methods for frequency tuning of the cavity are applied and the effects of these methods on the higher order frequency modes are studied. Contrary to previous experiences in other RF cavities, we propose to use a plunger as a tool for damping or shifting the HOMs instead of tuning the fundamental mode.

Characterizing and studying the nonlinear beam dynamics performance of Iranian Light Source Facility storage ring

In this paper, we will investigate the nonlinear beam dynamics issues (performance and optimization) of Iranian Light Source Facility storage ring. The strong sextupole fields together with the imperfections in a low emittance machine will result in the large detuning effects and driving the different order of the resonance lines. We have used most recently achievement for the nonlinear optimization of the storage ring. We have optimized the nonlinearity of the lattice by analyzing the resonance driving terms, direct dynamic aperture tracking and frequency map analysis calculations. We have evaluated the performance of the lattice against different imperfections such as magnet misalignments, multipole harmonics, fringe field of the quadrupoles and insertion devices. Furthermore, the effect of the lattice imperfections on the off-momentum particles dynamics has been studied through momentum acceptance and lifetime calculations.

The numerical investigation of a versatile IR-FEL for the Iranian light source facility

We have discussed a versatile three-color IR-FEL scheme as an insertion device for Iranian light source facility which can works in three different wavelengths in the range of infrared spectrum. Three output wavelengths are regarded in tune with the electron beam parameters at the exit of three linacs of the ILSF pre-accelerator section. Studies have been done in the context of a 1D numerical method governing the nonlinear dynamics of a single-pass FEL. The characteristics of the FEL output corresponding to three different electron beam energies have been presented and discussed.

Gas bremsstrahlung shielding calculation for first optic enclosure of ILSF XPD beamline

Gas bremsstrahlung is generated in high energy electron storage ring and accompanies the synchrotron radiation into the beamlines, where both strike the various components of the beamline. In this paper, radiation shielding calculations for secondary gas bremsstrahlung are performed for the First Optics Enclosure (FOE) of X-ray powder diffraction (XPD) beamline of the Iranian Light Source Facility. Dose equivalent rate (DER) calculations are accomplished using FLUKA Monte Carlo code. A comprehensive study of DER distribution at the back wall, sides and roof are given.

Design and fabrication of a preamplifier to be used with a MWPC at the ILSF

The Iranian Light Source Facility (ILSF) is a new 3 GeV third generation synchrotron radiation facility in Middle East, which at the time being is in its design stage. For day one operation of the ILSF a custom made two-dimensional multiwire position sensitive detector with delay line readout will be used in small/wide angle scattering and diffraction experiments with synchrotron radiation. For many years such X-ray detectors have played an important role in these synchrotron radiation experiments and owing to their robustness they are still in use in many places. Paired with state of the art read-out electronics they are serious low cost competitors to other solutions based on solid-state hybrid pixel detectors. To achieve minimum dead time and high global count rates these detectors will require preamplifiers with certain characteristics, which involve low noise, good signal/noise ratio (better than 20 dB), high gain, short rise time (lower than 10 ns) and pulse duration shorter than 120 ns. In this paper, we present the design and first results of the evaluation of a voltage preamplifier developed at ILSF within a collaboration agreement between ILSF, Iran and the Italian Synchrotron Radiation Facility (Elettra), Italy. The application of this preamplifier in an in-house multiwire detector is discussed and results are presented.