Technical University of Lodz (TUL),
Institute of Applied Radiation Chemistry (IARC)
ul. Wroblewskiego 15,  93-590 Lodz,  Poland
( +48 42 6313188,   +48 42 6313105
fax: +48 42 6840043,   +48 42 6360246
e-mail: mitr@mitr.p.lodz.pl


The infrastructure offered to Transnational Access consist four complementary set-ups based on the ELU-6e Linac at single location:

 the Faraday cage

P.R. detection system in the Faraday cage

 

  • PR1  - pulse radiolysis system using electron beam pulses of duration variable from 2.5 ns to 4.5 s, dose per pulse from 2 Gy to 1 kGy, wavelength spectroscopic range 250-2000 nm in the room temperature, recorded data time range from 500 ns to 2 seconds F.S. (full scale) with 1 ns resolution time. Data recording can be executed with two digital storage oscilloscopes - Tektronix TDS540 and Philips PM3320 with four different time sweeps, allowing short- and long-lived transients simultaneous observation due to only single pulse excitation.
  • PR2  - low temperature pulse radiolysis system same as PR1, but designed for investigations in liquid helium and liquid nitrogen cryostats (Oxford Instruments Ltd.) are utilized in the range 6-273 K.

 

  • PR3  - long time range detection pulse radiolysis system same as PR1, but with recorded data time range extended to seconds F.S. (full scale) for selected biochemical experiments. Extension to time range up to 10 min. is planned within TA project.

 

  • PR4  - pulse radiolysis conductivity system same as PR1, but equipped with 10 MHz HF-bridge for conductivity measurements in liquid phase. Recorded data time range from 50 s to 50 ms F.S. (full scale). Will be operable after purchasing conductivity cell with carbon glass electrodes.

The USSR made Linac ELU-6e has been constructed by the Elektronika Company and was installed at the Institute of Applied Radiation Chemistry in 1983. The ELU-6e has been solely dedicated to pulse radiolysis experiments and related work in the field of radiation chemistry. Accelerator specifies with the following nominal parameters: electron energy 6 MeV, pulse duration 2.5-10 ns with the electron beam (E.B.) peak current 10 A and 0.5-4.5 s with E.B. peak current 1 A, repetition rate 0.5, 1, 2, 20, 50 Hz and single pulse mode, maximum E.B. mean power 1.5 kW at 50 Hz repetition rate. Travelling wave type accelerating section is powered by magnetron MI-470M operated at a frequency 1886 MHz The pulse power at the output of the magnetron is 10 MW. A rectangular waveguide 12057 mm2 in cross section filled with air at a pressure of 5 atmospheres is used to feed the accelerating structure with microwave energy. The waveguide is separated from a vacuum system using ceramic windows. The accelerating section is under pressure < 510-6 Torr, secured by two titanium vacuum pumps and a forevacuum oil pump.


Block diagram of ELU-6e linac

The MI-470M pulse generator operates with a delay line and TGI1-2500/50 ceramic thyratron high power switch. Three-electrode gun operates in a pulse regime at a voltage of 40 kV in nanosecond and 20 kV in microsecond mode respectively. ELU-6e linac is located in a specially developed place equipped with adequately shielded walls.The experimental room placed in a Faraday cage has a surface area of 6 m2 and is equipped with independent line supply and grounding systems to avoid distortions produced by accelerator.The console and control system of the accelerator is in the same place as Faraday cage.


The pulse radiolysis setups consists of two digital storage oscilloscopes (DSO) - Tektronix TDS540 and Philips PM3320 - that are fully controlled and programmed via GPIB interface. The possibility of independent, simultaneous recording of transient absorption data on four different time sweeps saves experimental time and amount of valuable samples.

 

Transients are detected by UV/VIS/IR absorption spectroscopy using OSRAM XBO150W/1ofr xenon lamp as a source of analytical light. Xenon arc lamp operates in a stationary or in a pulsed mode resulted in 8-fold increasing of the light intensity for the time of 4 ms.

General view of the measuring system in linac room

Data acquisition system includes a Spectra Pro-275 monochromator (Acton Reseach Corp.) and photodetectors: 5-stage photomultiplier tubes (Hamamatsu R-928 or RCA 1P28) or photodiodes InAs-A100 (Barnes), J12-TE2 (Judson) covering the optical window 250-2000 nm. The dedicated programs written in Delphi 3 (Borland) control data acquisition system over the GPIB and processing stored in PC digital data within Windows 9x OS.As a complementary to pulse radiolysis system IARC offers other instruments and facilities:
 

Co60 gamma irradiation chamber with 25 kCi load.The chamber is the largest in Poland and allows to carry out diversed experiments in the laboratory and semi pilot scale. Modern ESR spektrometer, femto to nanosecond pulse lasers, choice of UV/VIS/IR spectrophotometers, spectrofluorometer, stop-flow system, radiotermoluminescence set-up, advanced instrumentation for studying solid polymers and polymer solutions, radiochemical instrumentation etc.
 


*******.