Hem-Behag is a late night (samay) raga in North Indian classical music that was composed by Ustad Baba Allauddin Khan.
Origin Hem-Behag has principal roots in a more common raga, Bihag. Hem-Behag or Bihag takes aspects of Raga Hemant. The raga centers around shudha Madhyam (vadi) and Ni (samavadi), but this is variable.
Structure Arohana: Ni Sa Ga Ma(shuddh) Pa Ni Sa Avarohana: Sa Ni Dha Ma(shudha)Pa Ma Ga Ma Re Sa
Good sources for listening would be:
Ali Akbar Khan & Ravi Shankar performing an alaap (introduction) in their live In Concert 1972 album (released 1973 on Apple Records). Nikhil Banerjee
References
In Concert 1972 (released 1973, Apple Records), track 1 (Ravi Shankar introduces this raga and attributes it as a composition of Ustad Allaudiin Khan's).