In this study, we build and test a prototype of an interstitial cooling device in a tissue-equivalent gel phantom mimicking the human neck. The effectiveness of the device is measured by the capability of delivering a coolant temperature of lower than at the entrance of the device and the measured temperature decay along a glass tube filled with water circulating at a speed similar to that in the carotid artery. The experimental study has identified a cooling prototype design, which is capable of inducing sufficient temperature reduction along the common carotid artery. It also tests how easy to handle the device to ensure a close physical contact between the device and the glass tube. A coolant temperature can be delivered at the device entrance when using above coolant in the reservoir. The surface temperature of the device is found almost uniform. Despite its limitations, the experimental results agree generally with previous theoretical predictions. The 8 cm long and 3 cm wide device with a coolant temperature lower than is capable of inducing a temperature reduction of at least along the glass tube filled with water circulating at 240 ml/min. For higher water flow rates, one needs to increase the length of the device and/or lower the coolant temperature to achieve similar temperature decays along the glass tube.