IR FEL Facility(TARLA)

TARLA : Turkish Accelerator and Radiation Laboratory at Ankara

 A superconductivity electron linac based Infrared Free Electron Laser ( TARLA ) facility is under construction on a first facility of TAC in Ankara University, Gölbaşı Campus of Ankara University in Gölbaşı, Ankara Turkey. 

The TARLA aims to obtain FEL between 2.5-250 µm using electron beam in the range of 15-40 MeV. A high average current thermionic DC gun running up to 300 keV will be used as an electron source. In order to scan desired wavelength range 2-250 µm range, two undulators with 2.5 cm and 9 cm period length will be utilized in two different optical resonators. There will be a transport line for Bremsstrahlung station. The main parameters of TARLA facility are given in following tables:

 
Table 1‑1. Expected Beam Parameters
 
Parameter
Unit
Value
Beam energy
MeV
15-40
Max.average beam current
mA
1
Max. bunch charge
pC
77
Micro pulse repetition frequency
MHz
13
Micro pulse length
ps
0.5-10
Transversal emittance
mm.mrad
< 13
Longitudinal emittance
keV.ps
<  50
Macro pulse length
µs
40 – CW
Macro pulse repetition frequency
Hz
10- sCW
 
Table 1‑2. Expected FEL Parameters
 
Undulators
U1
U2
Wavelength [µm]
2-25
18-250
Pulse Repetition Rate [MHz]
13
13
Max Peak Power [MW]*
~5
~2.5
Average Power [W]*
0.1-40
0.1-30
Max. Pulse Energy [µJ]*
~10
~8
Pulse Length [ps]*
1-10
1-10
 
*         Depending on the wavelength of FEL

 

 

 

Experimental Stations :

A.IR FEL Stations :

TARLA, as a national facility is charged with the responsibility to supply state-of-the-art radiation over a broad energy region to a diverse user community. Initial studies on the possibilities and basic performance of TARLA demonstrated promising capacity in the wavelength range of 2.5-250µm. Considering the tunability, high power and short pulse structure of the FEL, we propose to use IR FEL in following research areas at 8 experimental stations. The laser beams from the two undulators will be transported to eight experimental stations with a beam transport optical systems composed of vacuum beam ducts and mirror systems. One of these rooms will be diagnostic room of FELs. In this room, the quality of the laser beam will be studied. The time structure, intensity, spectroscopic bandwidth and other properties of the FEL light will be investigated and monitored in this room and then will be transported to each experimental room.

The second room will be used for general IR FEL Spectroscopy (vibrational and rotational IR spectroscopy for solid, gases and liquid materials), FT-IR spectroscopy, Raman spectroscopy. The third room will be used for investigation of material science and semiconductors. These investigations will be carried out by using the sum frequency generation and pump-probe techniques. In addition, Terahertz Laboratory and laser material processing laboratory are under discussion depending on the application areas.

We identified areas of interest and contacted specific researchers for the user meetings. Firstly, a few areas of interest were defined:

 

 

·         Conventional Laser versus IR FEL
·         Non-linear optics
·         Pump-probe Techniques
·         Sum frequency generation
·         IR, FTIR, Raman Spect.
·         Optics and signal process
·         Terahertz Spect.
·         Nanotechnology
·         Material Science
·         Semi-conductors
·         MALDI MS
·         ATR FTIR
·         Elipsometry
·         Laser Chemistry
·         Molecular spectroscopy
·         Laser desorption
·         Laser ablation
·         Nanomedicine

 

            
National and international user meetings were held covering the physicists, chemists and biologists since 2009 to define the research potential of the TARLA facility and the technical structures of planned IR FEL experimental stations.

B. Bremsstrahlung Station:

Bremsstrahlung is a German word and means “breaking radiation”. It is used to describe the radiation which is emitted when an electron (a charged particle) is decelerated in an electric field. Using this method a photon beam can be produced. The photon can be used in a variety of fields including in both fundamental nuclear or particle physics research and application fields. The photon is an ideal probe to investigate nuclear structure and the interaction of the photon with the nucleus depends on incoming photon energies. As it can be used in a variety of fields (from industry to medical) it is important to have such a station in TARLA. It is planned to establish two LINAC each produce max 38 MeV electron beam and from those of electron beam it will be possible to get 0-35 MeV bremsstrahlung photon beam. As long as there will not be any problem, the bremsstrahlung photon beam will be ready to perform experiment in 2017.

www.tarla.org.tr