A prominent physicist has been ordered to spend up to 30 years in prison for sexual crimes involving an underage girl in Bucks County.

Thomas N. Padikal, 71, was sentenced late Tuesday to 15 to 30 years behind bars. A county jury had convicted him in June of involuntary deviate sexual intercourse with a child, aggravated indecent assault of a child, and related offenses. The verdict was announced after less than an hour of deliberation.

Padikal, in addressing Common Pleas Court Judge Raymond F. McHugh on Tuesday, tried to blame the victim, whom he began abusing in 2007 when she was 8 years old. He told McHugh that the girl had approached him and that he had tried to shun her advances.

His assertions ran counter to voluminous evidence presented during the trial, including Padikal’s own words, recorded in recent prison phone calls in which he tried to persuade the victim to drop the case in exchange for money and a marriage proposal.

“Many times, we don’t get to bring charges forward in cases like these, let alone receive a successful prosecution,” Deputy District Attorney Kristin McElroy, the lead prosecutor in the case, said Wednesday.

“Because of the investigation that Bensalem completed, we had a really strong case,” she added. “We were lucky to prosecute something this strong, with so many different types of evidence.”

Padikal’s attorney, Evan T.L. Hughes, did not immediately respond to a request for comment Wednesday.

The investigation began last year, when the victim — now 19 and living in Texas — called the Bensalem Police Department to report abuse that she said had taken place almost daily when she was a child, according to the affidavit of probable cause for Padikal’s arrest.

After the girl moved from Bucks County, Padikal tracked her, following her on social media and creating a private website devoted to her, investigators revealed during the trial.

They also uncovered PowerPoint presentations the physicist had made that featured photos of nude women with the victim’s face superimposed onto the bodies.

Padikal, who specializes in radiology and oncology, moved to New Jersey in the years after the abuse. He was arrested there in November by state police.