Tanya Walls, Guernsey Museum’s assistant archaeologist, and geophysicist Louise Randell organised the survey at Longis after the remains were found last year.
The survey was in conjunction with the Alderney Society who obtained permission from the land-owners, Driffield Estates.
During the work, the team used an electrical earth resistance meter to determine foundations, ancient walls, holes and rubbish pits down to a depth of just over a metre.
Ms Randell, who supervised the ground readings, said such equipment had been around for a long time and is used in the first stage of mapping subsurface archaeological features.
Ms Walls believed the nunnery area at Longis was one of the most important archaeological sites in the Channel Islands.
‘This is the first time this equipment has been used on Alderney and it will be a good field-test for us to see the width and extent of the site found last year,’ she said.
‘Resistance testing means we can view the undersoil features and pinpoint specific areas of interest rather than dig random test pits.
‘It saves a lot of effort for our volunteers and makes our work more effective and efficient.
‘We are very grateful to the owners, Driffield Estates, and the tenants of the land below the Coastguards Cottages to allow us to test the area and hopefully continue the dig this year in the right areas.
‘The States of Alderney were helpful too with permission granted for work on the eastern boundary.’
The equipment was loaned to the museum by La Societe Guernesiaise.
It is hoped a new excavation in the fields will take place in July.