“Clean” Liquid Helium

The authors are greatly appreciative and acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the Project No. MAT2015- 64083-R and through the Personal Tecnico de Apoyo (PTA) 2016 program for personal funding. They would also like to acknowledge the use of Servicio General de Apoyo a la Investigacion-SAI, Universidad de Zaragoza