The performance evaluation of gamma- and neutron-sensitive superheated emulsion (bubble) detectors

Abstract

The superheated emulsion (bubble) detectors have been developed at Defence Laboratory, Jodhpur (DLJ), India, for measurement of gamma doses. The developed detectors have been tested at Radiation Safety and System Division (RSSD), Bhabha Atomic Research Center (BARC), Mumbai (India) and DLJ having ISO-17025 accredited facility for testing and calibration of Radiation Monitors. A series of experiments were conducted to determine the gamma and neutron sensitivity of these detectors, i.e. batch homogeneity, reproducibility, dose equivalent rate effect, gamma/neutron dose equivalent response, gamma/neutron energy response and change in gamma sensitivity as a function of temperature. All the results were within +/- 20% of themselves. It is observed that the response of the detector is dependent upon temperature. The recommended ideal working temperature range of the detector is 20-28 degrees C, but a temperature correction is required beyond approximately 30 masculineC. The temperature compensation may be possible up to 45 degrees C in improved version using specially prepared reversible thermo-sensitive polymer gel. The detector may have applications in radio-diagnosis, R&D laboratories, and health physics as well as an indicator of gamma radiation for dirty bomb to be useful for first responder in any radiological emergency.

Neutron measurements with ultra-thin 3D silicon sensors in a radiotherapy treatment room using a Siemens PRIMUS linac

“…An active characterization of RT environments is complex due to the pulsed nature of the mixed γ -neutron field and the high γ -ray background, so the use of neutron passive detectors has been widely recommended to avoid instrumental problems from active devices such as signal pile-up (AAPM 1986). Previous works with passive methods have been based mainly on activation of foils in Bonner spheres (García Fusté 2010), TLD dosimeters (Barquero et al 2005), and superheated bubble emulsions (Vaijapurkar et al 2008), among others. These methods are time consuming since the detectors need to be read in an external laboratory after the exposition, so they are not widely used in clinical facilities.…”

Study of low frequency acoustic signals from superheated droplet detector

“…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.…”