Danny Kilburn, 21, was working with children at the Oranges and Lemons Nursery in Dundee as he amassed one of the worst collections of child porn pictures and videos ever recovered by Scottish police.
He boasted online about abusing a girl in his care and when police raided his home he was found to have more than 11,000 images of children being abused.
Kilburn, who was distributing the sickening material for payment, was found with so many videos it would have taken over 24 hours to watch them all.
Kilburn, of Glenrothes, Fife, admitted being involved in the distribution of indecent images when he appeared at Perth Sheriff Court. He also admitted taking, or permitting to be taken, indecent images of children.
Kilburn had been working at the nursery for more than a year when police discovered he was boasting about abusing a child in his care.
The support worker had also previously carried out work experience at the city's Little People Nursery, Daisies Kindergarten and Buttons and Bows.
Fiscal depute Carol Whyte told the court that information was received by Tayside Police in October 2012 that indecent images had been accessed.
She added: "The owner of the equipment had been communicating on chat rooms with like-minded people and had indicated that he worked in a local nursery and was abusing a female child from the premises.
"The man also boasted on the chatroom site that he had a sexual interest in children whom he regularly abused. The man used the pseudonym Dan Dan when involved in the chat room."
The court heard the information was taken seriously and urgent inquiries were carried out to trace the computer owner to his home address. His home was raided on October 9 last year, while he was with his family and two laptops, memory sticks and a mobile phone were taken away.
The court heard he could give no explanation for his behaviour, other than saying it was an 'adrenalin rush'.
Kilburn, who was sacked, denied he had ever sexually abused children at the nursery where he worked and the police inquiry found no evidence of any abuse.
A haul of 11,617 indecent images of children and 340 videos with a total running time of more than a day.
Among the massive haul were hundreds of images and 16 videos rated as the worst on the scale.
Fiscal depute Carol Whyte said: "The accused admitted file sharing the indecent material with other people and discussing sexually abusing children with people in chat rooms.
"He claimed this activity had taken place over the course of a maximum of a year. He could give no explanation as to why he did this other than to say it was for the adrenalin rush he got by doing something he knew was wrong.
"He denied he had ever sexually abused children in the nursery where he worked. The police inquiry did not find any evidence of such abuse and it seems the accused's claims in the chat rooms were an act of bravado."
Parents of children at the nursery were informed by letter that a member of staff had been suspended pending the outcome of a police investigation. Kilburn was then sacked.
Ms Whyte told the court the police recovered a total of 11,617 indecent images of children and 340 videos with a total running time of more than a day.
It is difficult to quantify how much of the material had been distributed onwards by Kilburn, but at least 200 images had been sent to other paedophiles, the court heard.
Kilburn was placed on the Sex Offenders Register and bailed for reports. He is banned from being alone with children and using any device which can access the internet.