Radiation measurement in the environment of FLASH using passive dosimeters

Abstract

Sophisticated electronic devices comprising sensitive microelectronic components have been installed in the close proximity of the 720 MeV superconducting electron linear accelerator (linac) driving the FLASH (Free Electron Laser in Hamburg), presently in operation at DESY in Hamburg. Microelectronic chips are inherently vulnerable to ionizing radiation, usually generated during routine operation of high-energy particle accelerator facilities like the FLASH. Hence, in order to assess the radiation effect on microelectronic chips and to develop suitable mitigation strategy, it becomes imperative to characterize the radiation field in the FLASH environment. We have evaluated the neutron and gamma energy (spectra) and dose distributions at critical locations in the FLASH tunnel using superheated emulsion (bubble) detectors, GaAs light emitting diodes (LED), LiF-thermoluminescence dosimeters (TLD) and radiochromic (Gafchromic EBT) films. This paper highlights the application of passive dosimeters for an accurate analysis of the radiation field produced by high-energy electron linear accelerators.

Neutron field characterisation in a high-energy proton–synchrotron environment using bubble detectors

“…This paper confirms the application of BDT and BDPND type superheated emulsion (bubble) detectors for the assessment of neutron fluence distributions confined to three energy bins. The data could be used for the interpretation of radiation effects, including neutron kerma calculations and single event upset (SEU) prediction for microelectronic devices installed in a high energy accelerator environment (Mukherjee et al, 2007).…”

Coil-free active stabilisation of extended payloads with optical inertial sensors

“…However so far, to the best of the authors' knowledge, all of them are using electromagnetic sensors for inertial control at low frequency, which are not compatible with the environment of particle colliders [17]. Other sensitive seismic sensors exist but they also measure some parasitic signal due to the surrounding magnetic field and the particle beam; either the sensor flexure is build in a ferromagnetic material [5] or it includes elastomer or eletronics [18] which are damaged by the highenergy particle beam. New sensors based on an interferometric readout have been developed which can provide an accurate signal in this harsh environment [19][20][21].…”

Study of low frequency acoustic signals from superheated droplet detector

“…A superheated droplet detector (SDD) [1,2] consists of a large number of micron sized superheated liquid droplets dispersed in a viscoelastic gel [1] or in a soft polymer [2] medium. SDD is known to be able to detect neutrons [3,4], gamma-rays [5,6] and other charged particles [7,8] under certain operating temperature and pressure [5,9]. In SDD, each droplet can be considered as a micron size bubble chamber [10][11][12], where a drop vaporizes when sufficient energy is deposited by the energetic radiation.…”

“…SDD is widely used in neutron spectrometry [21][22][23][24] and neutron dosimetry [23][24][25][26], and considered as a efficient neutron detector in specified temperature and pressure regions, where it is not sensitive to gamma-rays [4,22,27,28]. The gamma-ray sensitive temperature provides a lower cut on the neutron detection in a mixed neutron-gamma ray field.…”