# LET as function of depth

hello dear expert.
as the other colleague has already mentioned, USRYIELD allows us to calculate the crossing LET between two regions. in our case we want to evaluate the LET at depth as we calculate the dose yield at depth with USRBIN. which FLUKA detector is suitable for doing this? is it possible to use DOSEQLET? if yes how to deduce the LET?
what then is the meaning of DOSEQ? any help will be useful for the determination of the LET in depth

Dear Tomfey,

Indeed. Note that what you obtain in this way is a spectrum of LET (subject to whatever range of the second quantity you define in the `USRYIELD` card). A priori you could segment your geometry with various planes and put a `USRYIELD` at each plane. Depending on the number of planes you need to define within your geometry, this method becomes impractical.
There is no built-in scoring in FLUKA to directly evaluate LET as a function of depth. Note that the `DOSEQLET` is a dose not a LET (see the manual for the definition of that quantity).