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RXTE Cook Book: Common Bitmasks
Recipes from the RXTE Cook Book

For your convenience, we provide sets of common bitmasks for almost all of the PCA event modes**. You should check carefully that you are using the correct bitmask for your data configuration; often, the tools will be perfectly happy to operate with a bitmask which is not what you intended. If you want a different combination of detectors or anodes, you will have to make your own using sefilter following its recipe.

If the bitmask you need has an asterisk next to it, then the data will have to be filtered with fselect before extraction as explained in the selection recipe.

Find your data mode (as shown in the AppId window of XDF or in the keyword DATAMODE of the fits event list) in the first column; x indicates the binning (A,B,C,M, or N), ll is the lower channel boundary, and rr the readout time. The next three columns tell you what you can select from that configuration, and the last column has the link to the correct table for chosing a bitmask:

Event modes

ModeCan I select by ... Bitmask
time marker?detector?layer?
GoodXenon** NA YES YES Table 1
YES YES NO Table 2
E_1ms_128x_ll_rr YES YES YES Table 3

Notes: the bitmasks in Table 1 are only for GoodXenon mode data where there are no propane events present. If you specifically requested propane events, these bitmasks will not give the correct result; you will have to make your own. (See the recipe and notice the warning at the bottom.) (If you are not sure, simply use fkeyprint to look at the value of DATAMODE; if propane events are included, the keyword will be GoodXenonwithPropane.)

Also, many of these bitmasks will not look like what you would get using sefilter yourself. We have removed the default bitmask which filters out the M[1]{1} token; since GoodXenon data have no time stamps, filtering on this token is unnecessary and will take longer in fselect. Where possible, we have also simplified the expressions produced by sefilter in order to make the selection process as efficient as possible. (Sefilter's algorithm is designed to be correct for every possible case, and so it may not be the most efficient.)

The event mode E_500us_64x_ll_rr is not currently included due to an oddity in the original processing of this event mode. If you have AO1 data of this type, wait for the reprocessed data and do not attempt to use this mode from the originally processed version.

Table 1:

Bitmasks for GoodXenon
ALL none bitfile_gx_d012 bitfile_gx_d0123 bitfile_gx_d0124*
LR1 bitfile_gx_lr1 bitfile_gx_lr1_d012 bitfile_gx_lr1_d0123 bitfile_gx_lr1_d0124*
LR1,LR2 bitfile_gx_lr12 bitfile_gx_lr12_d012 bitfile_gx_lr12_d0123 bitfile_gx_lr12_d0124*
LR3 bitfile_gx_lr3 bitfile_gx_lr3_d012 bitfile_gx_lr3_d0123 bitfile_gx_lr3_d0124*

Table 2

(D token)
DETECTORS ALL0,1,20,1,2,30,1,2,4
(no layer information) bitfile_M bitfile_d_d012 bitfile_d_d0123 bitfile_d_d0124*

Table 3

(Z token, case C[]{7})
ALL bitfile_M bitfile_z_d012 bitfile_z_d0123 bitfile_z_d0124*
LR1 bitfile_z_lr1* bitfile_z_lr1_d012* bitfile_z_lr1_d0123* bitfile_z_lr1_d0124*
LR1,LR2 bitfile_z_lr12* bitfile_z_lr12_d012* bitfile_z_lr12_d0123* bitfile_z_lr12_d0124*
LR3 bitfile_z_lr3* bitfile_z_lr3_d012* bitfile_z_lr3_d0123* bitfile_z_lr3_d0124*

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This page is maintained by the RXTE GOF and was last modified on Thursday, 16-Sep-1999 08:38:12 EDT.