What are booster stages in aviation Gas Turbine

[Kshitizagar]

Guys, I was reading about Turbofan and somewhere while browsing Defence Turbofan engines I came across Booster stages, but I didn't find any description or what are booster stages in Gas Turbine (Axial Compressor)

 

[Pkruse]

I design gas turbines, & I've never heard that term for turbofans. Only has meaning to me with regard to rockets.

 

[Travis_King]

The booster is a low pressure compressor stage. Prior to ramping up the pressures with the HP compressor stages, (or in cases where the bypass is used to boost pressure for addition downstream) the air will be gradually brought up in pressure by LP stages, sometimes called booster stages.

 

[Kshitizagar]

Thank You Travis King... tell me one thing more if fan and booster stages are driven by one LP turbine then is it necessary that we have gearbox in between booster stage and fan. Because as far as I know there Speed (rotational) difference between LP compressor and fan