Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improved measurement of the head-tail effect in nuclear recoils   We present new results with a prototype detector that is being developed by
the DMTPC collaboration for the measurement of the direction tag (head-tail) of
dark matter wind. We use neutrons from a Cf-252 source to create low-momentum
nuclear recoils in elastic scattering with the residual gas nuclei. The recoil
track is imaged in low-pressure time-projection chamber with optical readout.
We measure the ionization rate along the recoil trajectory, which allows us to
determine the direction tag of the incoming neutrons.

27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th