Multipurpose Irradiation Facility Equipped in Electron Accelerator Devices

Marko Fülöp

University Centre of Electron Accelerators

of Slovak Medical University, Bratislava

INTRODUCTION

Usually in practice, it appears that the more simplified equipment for only one method of use, has got the more reliable operation with lower operational cost. However, this is less true for equipment for science and research, when the economic benefits of projects cover the increased operating costs. Also, in industrial applications of electron accelerators for reducing the environmental burden caused in the past, the versatility of the irradiation facility appears to be advantageous.

Radiation aging test of CERN accelerator component by dose 2 MGy

Hospital Antolska,cornea transplanta-te sterilized by 10 kGy photon dose

SAS Institute of Zoology, Honey for treatment of severe ulcers rotationally sterilized by 25 kGy dose.

Research and development in the multipurpose facility UCEA of Slovak Medical University with LINAC 5MeV/1kW

Detector GaAs preparation Detector irradiation Detector testing

Modification of properties of semiconductor detectors

Metrology application of electron accelerator - electron beam as a source of high absorbed dose rate

Control of waveform is critical parameter for repeatability.Electron beam is directed to a targed after the waveform is standard. The targed is irradiated by adjustable number of pulses.

Nonstandard waveform Standard waveform

Electron or photon irradiation of communication unit of satellite skCubein 13 steps up to a total dose of 900Gy (90 krad)

Within the last decades sheep wool as textile raw material has got a strong concurrent – synthetic fibres. However, sheep-breeding is an important part of economy in many countries with mountain meadows. While other products of sheep-breeding are well-marketable, wool is an undesirable waste often. Necessary the sheep-shearing and legal liquidation of danger wool waste present financial loss with no profit.

COMPETITION

Constantine the Philosopher University in Nitra, Slovakia, Faculty of Natural Sciences, Department of Chemistry, Porubska, M.

Utilization of electron beam to modify sheep wool

Basic characteristics of multipurpose facility with electron accelerator for radiation processing

Electron accelerator - Vertical beam- Adjustable electron energy- Adjustable electron beam current- Adjustable scaning frequency and width

Material transport- Conveyor or trolleys with an adjustable speed up to

moving step by step for adjustable period- In space under electron beam part of the conveyor

should be dismounted for montage other material fixturing

Multipurpose facility with electron accelerator for treatment of environment

For remedation of environment by radiation, an irradiatiors with mulitipurose electron accelerators should be, in addition, transportable with environmentally friendly operation.

Relocation capabilities of these electron beam irradiators guarantee a possibility that after the removal of the current environmental burden will be removable, thereby avoiding further use waste imported from distant surroundings.

A desirable feature of a transportable device is its transportability by road.It has been made more mobile irradiators with shielded electron accelerator. Dimensions of the mobile shielding restricted the power of electron accelerator result in a relatively expensive operation of electron accelerator for radiation processing methods.Bellow is shown an interesting mobile unite EB TECH Co.

One from serious problems in applications of radiation processing methods in environment in relatively high investment and operational cost in comparison to traditional remedation methods. From this point of view the suitable type of irradiation unit with electron accelerator for environmental application should be chosen with regard to: 1. Accelerator reliability (availability), 2. Average beam power (productivity), 3. Electrical and beam utilization efficiency (cost of exploitation), 4. Electron energy (penetration), 5. Transportable shielding 6. Price (investment cost).

Ad.1. Accelerator reliability (availability)

The following components can be recognized as critical from point of view electron accelerator reliability/availability (Z. Zimek, 2008):

- Gun (type of gun, cathode life time),- RF source (klystron, magnetron, life time),- Output foil

Remark : Accelerators DC transformer type 50/60Hz are not using the RF sources, which is one from arguments about their higher reliability

Ad.2. and 4. Initial investment costs on electron beam and energy

Ad. 3 Electrical efficiency (cost of exploitation)

Ad.3. Electrical and beam utilization efficiency (cost of exploitation)

Absorbed dose (D) desired for product mass throughput rate (M) under the electron beam radiation:

 

 

Where:eA is electrical efficiency of accelerator (>90% for DC 50/60Hz transformer accelerators), eb is electron beam utilization (at present about 70%)

𝐷ሺ𝑘𝐺𝑦ሻ= 60.𝑃ሺ𝑘𝑊ሻ .𝜀𝐴 .𝜀𝑏 𝑀(𝑘𝑔.𝑚𝑖𝑛−1)

Depth dose distribution in liquid sample irradiated by 2,5MeV electron beam (calculated by the code ModeRTL)

For acceptable value of irradiation dose 17 kGy in surface layer only area of absorbed dose under red line is effective (in layer 0,5 cm it is 445 kGy. Dose 397 kGy (47% of total delivered dose) in sample layer 0,5 cm under blue line but outside of the area under red line is ineffective. This relative high value of ineffective dose is challenge for increasing of beam irradiation efficiency.

Ad.5. Transportable shielding of high power electron accelerator Transportable unit : empty modular boxes (racked each into other) for shielding and accelerator, are transported by trucks to locality of interest.In the site of electron beam application, the modular shielding is completed and modules are filled by appropriate shielding material that was chosen with regard to beam power and electron energy produced by accelerator. The engineering design and composition of shielding material for various electron beam energies from 2,5MeV/100kW up to 5MeV/100kW has been calculated by the Monte Carlo code MCNPX.

Transportable multipurpose electron irradiator with accelerator ELV 8 2,5MeV/100kW

Modules designed for various electron beam applications

CONCLUSIONS

Any practical accelerator construction for using in enviromnet must be compromise between purposes of applications, efficiency, reliability, energy, compactness and cost.Improvement of DC transformer 50/60Hz accelerators with electron energy above 3MeV is desired for the effective environmental applications.

THANK YOU FOR YOUR ATTENTION

Pre ozdravovanie životného prostredia poškodeného predchádzajúcou činnosťou sa odporúča transportovateľné zariadenie vybavené výkonným elektrónovým urýchľovačom a modulmi tienenia, ktoré sa na mieste inštalácie zariadenia naplnia tieniacim materiálom nezaťažujúcim životné prostredie. Po odstránení záťaže životného prostredia a zariadenie demontuje, z tieniacich modulov sa vyprázdni piesok a štrk, ktoré môžu byť plnohodnotne použité v stavebníctve. Na novej lokalite životného prostredia sa zariadenie môže použiť na odtránení iného druhu záťaže použitím príslušného modulu ožarovania