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NAME mythen - Dectris Mythen 1K MCA
INTRODUCTION
The Dectris Mythen 1K is high-dynamic range, short readout
time and high frame rate MCA. spec supports
single and multiple frame acquisition, optionally gated and or
triggered. Frame rates greater than 375 frames per second are
possible with spec. Connection to the Mythen is
over a UDP socket with firmware version 1.x. Either UDP or TCP
is available when using Mythen firmware version 2.0 or greater.
Multiple units can be configured for use at the same time.
An issue remains with the initial Mythen support in
spec. During multi-frame acquisition at high
frame rates (presets less than 0.1 second), spec
is locked into a acquisition loop. Currently, not even
^C will abort the acquisition.
spec release 5.09.01-3 added support for
most features found in Mythen firmware 2.0. The Mythen can now
be configured for either UDP or TCP socket connections. Also,
spec will display messages associated with the
error codes now returned by the Mythen. In addition,
spec supports the the new Mythen commands for
toggling bad-channel interpolation, flat-field correction and
rate correction, for setting the dead-time constant tau,
for loading predefined settings and for optimizing settings to a
specified threshold. spec also supports the new
Mythen command to reset all the settings and parameters.
CONFIGURATION
Each Mythen 1K is configured on the MCA- and CCD-type
Aquisition screen of the the configuration editor
along the following lines:
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MCA- and CCD-Acquisition Type Device Configuration
MCA-like DEVICE ADDR <>MODE <>TYPE
0 YES mythen TrimCu Dectris Mythen (Socket UDP)
1 YES host:1030 Dectris Mythen (Socket UDP)
2 YES 192.168.0.90 TrimMo Dectris Mythen (Socket UDP)
3 YES host:1031 StdCu Dectris Mythen (Socket TCP)
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The TYPE can be configured for either UDP or TCP
connections (as of spec release 5.09.01-3).
Mythen firmware below release 2.0 only recognizes UDP
connections. The DEVICE name is either a resolvable
host name or IP address. A port number for the socket connection
can be specified. Otherwise, the default port of 1030 will be
used.
The ADDR field can optionally contain the name
of the initial trim or settings file to load. For firmware below
version 2.0, the names TrimCr, TrimCu and
TrimMo are recognized. If missing, the TrimCu trim
file will be loaded by default. For firmware at version 2.0 or
above, the names StdCu, StdMo, HgCr,
HgCu, FastCu and FastMo are recognized by
the Mythen. If no name is given, the existing settings on the
Mythen will be used, that is, no settings file will be loaded,
which will save several seconds for each module.
The spec code supports setting the optional
controller parameters "inpol" and
"outpol" through the configuration editor. Type
p from the main screen to bring up the optional
parameter screen.
OPERATION
The Mythen can be started and stopped from
spec two ways: in parallel with the
built-in count functions or manually. If auto-run mode is set
with
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the MCA will be started and stopped with the standard counting
commands used with the ct-type macros and with the
scan macros. If soft-preset mode is also set with
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mca_par("soft_preset", 1)
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the MCA will programmed with the same count time as the master
timer in count-to-time mode. In count-to-monitor mode or if
"soft_preset" is not set, the MCA will be programmed
with the preset time set using the mca_par()
"preset" option below. (Since the Mythen doesn't
retain data when stopped using software commands, it is not
possible to implement the normal MCA behavior in
spec where an unset "soft_preset"
means spec stops the MCA when the master timer
finishes.)
Note, a gate from the master timer or counter can be used to
gate the MCA so that the acquisition interval exactly matches the
master. If using such a mode, enable gating with the
mca_par() "gateen" option below.
When using "auto_run" mode, only one frame will
be acquired. In order to acquire multiple frames, use
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to start acquisition. As the Mythen can only buffer four data
frames, it is essential that spec read data as
it becomes available. That is done during the automatic hardware
polling built into spec. It is important not to
disable that feature with spec_par() or set too long
of a polling interval. In addition, one must not run commands
during multi-frame acquisition that will interfere with polling,
such as creating a subshell with unix().
MULTI-FRAME DATA
There are also two ways for spec to store
the Mythen multi-frame data. In the first method,
spec will allocate enough storage to hold the
data for the number of frames configured. The data can be
retrieved using the "frame" or "cframe"
options. The "frame" option returns the raw data.
The flat-field correction is applied to the data returned using
the corrected-frame "cframe" option.
In the second method or reading data, an appropriately
configured data array is designated using the
"array" option. The data array should be of type
ulong, the number of columns should be 1280, and the
number of rows should be at least as great as the number of
frames set with the "frames" option. For example, a
data array configured as
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ulong array data[200][1280]
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would accommodate 200 frames. The array can also be a shared
data array. spec will automatically tag the
array as "frames" and set the
frame_size and latest_frame elements of
the shared data header for the designated array, which will
enable optimal display of the data by an auxiliary utility such
as PyMca.
When the data is placed directly into a data array when using
the "array" method, if the
"autocorrect" option is enabled, the data will have
the flat-field correction applied. If the option is disabled,
the raw data is placed in the array.
Both methods for storing the data may be active at the same
time. However, to avoid allocating a large amount of memory
unnecessarily, if the "array" option is active,
spec limits the number of frames stored
internally, according to the value of the
"alloc_limit" option, which has a default value of
100, a maximum value of 10000 and a minimum value of one.
The standard mca_get() function will return the
first frame of multi-frame data.
PARAMETERS
spec can set all of the Mythen 1K
operational parameters using the mca_par() function,
as described in the following section. The parameters
"preset", "bits",
"frames", "delbef",
"delafter", "gateen",
"gates", "trigen",
"conttrigen", "threshold",
"inpol", "outpol",
"autocorrect", "alloc_limit" and
"verbose" will be retained in the user state file.
For firmware 2.0 or greater, values for the parameters
"badchan_interpolate", "rate_correct"
and "tau" are also saved in the state file. In
addition, "inpol" and "outpol" can
additionally be set as optional controller parameters in hardware
configuration file. Values set in the configuration file will
take precedence to values in the state file.
Before sending the start command to the MCA, any parameters
that have been updated will be sent to the Mythen. All
parameters will be updated on the next start command after
sending a "trimfile" or "settings"
command.
FUNCTIONS
When called with the optional argument, the functions below
will set the parameter to the value of the argument. With no
arguments, the functions will return the current value of the
parameter. It isn't possible for spec to read
parameter values from the Mythen, so the returned values are
those previously set using mca_par() during the
current session, or the saved values from the user's state file,
if not starting fresh.
Note, spec does not send commands to change
the parameters until the Mythen MCA is started, either using the
"run" command or during counting, when
"auto_run" is enabled. In particular, of the
following, the only commands that access the Mythen are
"reset", "threshold" (only when reading
the value), "autosettings",
"flatfield", "badchannels",
"trimfile", "settings",
"send" and "read".
If multiple MCA devices are configured in
spec, use the mca_sel() function to
designate the device to use with the mca_par() and
mca_get() functions, or use the
mca_spar() and mca_sget() forms of the
functions. See the
mca help file for more information.
mca_par("trimfile"
[,name]) - Returns the name of the
current trim file, or loads the specified trim file. The trim
file contains all the initialization parameters for the MCA and
is located with the MCA firmware. Each trim file has an
associated flat-field file. The flat-field data will be read and
stored by spec to be used for the optional flat-
field correction operation. (Deprecated with version 2.0
firmware.)
mca_par("flatfield") - Returns an unsigned
long data array containing the flat-field data as read from the
detector.
mca_par("preset" [,
seconds]) - Returns or sets the
preset value used when manually starting the MCA using the
"run" option, below. If the gate is enabled in
multi-frame mode, the preset is ignored by the Mythen, but if the
frame rate is greater than 10 frames per second, the preset
should be set to a value of 0.1 or less so that
spec will use a more robust method for reading
data at high frame rates.
mca_par("bits" [, value])
- Returns or sets the number of bits per channel for the Mythen
to use while acquiring data. Fewer bits allow for slightly
faster frame rates in multi-frame mode. Valid values are 4, 8,
16 and 24.
mca_par("frames"
[,number]) - Returns or sets the
number of frames to acquire when using a manual start. When
using
"auto_run" mode, where the MCA is started and
stopped with the master timer, only one frame will be acquired.
mca_par("latest_frame") - Returns the frame
number of the most recently acquired frame.
mca_par("delbef"
[,seconds]) - Returns or sets the
delay between trigger and the first measurement.
mca_par("delafter"
[,seconds]) - Returns or sets the
delay between measurements when accumulating multiple frames.
mca_par("gateen" [, 0|1]) - Returns or sets
gated-measurement mode (0 for disabled and 1 for enabled).
mca_par("gates",
[,number]) - Returns or sets the
number of gate signals for a gated measurement.
mca_par("trigen" [, 0|1]) - Returns or sets
triggered-measurement mode (0 for disabled and 1 for enabled). A
trigger starts the entire multi-frame acquisition or a separate
trigger is needed for each frame, depending on the value of the
continuous-trigger-enable parameter,
"conttrigen".
mca_par("conttrigen" [, 0|1]) - Returns or
sets repeated triggered-measurement mode (0 for disabled and 1
for enabled). With this mode, each frame needs a trigger signal.
mca_par("threshold"
[,value]) - Returns or sets the
threshold energy in keV.
mca_par("inpol" [, 0|1]) - Returns or sets
the input polarity for the trigger and gate signals (1 for
falling edge and 0 for rising edge). Can be set as an optional
parameter in the config file.
mca_par("outpol" [, 0|1]) - Returns or sets
the output polarity for trigger and gate signals (1 for active
low and 0 for active high). Can be set as an optional parameter
in the config file.
mca_par("run") - Programs the device with
updated parameters and starts acquisition.
mca_par("halt") - Halts acquisition.
mca_par("frame", number)
- Returns an unsigned long data array containing the data in
frame
number. Frame numbers start at zero.
mca_par("cframe", number)
- Returns an unsigned long data array containing the corrected
data in frame
number. Frame numbers start at
zero.
mca_par("array" [,
array]) - Returns or sets the name
of the data array to be used to receive multi-frame data. The
array name can be passed as the array variable or as a string.
The array should be type
ulong, the number of
columns should be 1280, and the number of rows should be at least
as great as the number of frames.
mca_par("autocorrect" [, 0|1] - Returns or
sets the mode where data placed directly into the designated data
array has the flat-field correction applied. A zero disables
autocorrection, while a one enables the mode. With version 2.0
firmware and above, the correction is performed within the
Mythen.
mca_par("autosettings" [,
threshold]) - Tells the Mythen to
load suitable settings corresponding to the value of
threshold. Units are keV. If the optional
argument is missing, the value set via the
"threshold" command is used. If that value is
unset, uses the threshold value initially read from the Mythen.
(Requires version 2.0 firmware.)
mca_par("settings" [,
name]) - Without the optional
argument, returns the name of the current settings designation.
Otherwise, sends the Mythen the command to load the settings
associated with
name. (Requires version 2.0
firmware.)
mca_par("badchan_interpolate" [, 0|1])
- Returns or sets bad-channel interpolation mode. When on, the
Mythen replaces values in channels marked as bad with values
interpolated from neighboring channels. (Requires version 2.0
firmware.)
mca_par("rate_correct" [, 0|1]) - Returns
or sets rate-correction mode. (Requires version 2.0 firmware.)
mca_par("badchannels") - Returns the bad-
channels array. (Requires version 2.0 firmware.)
mca_par("tau" [, value])
- Returns or sets the dead-time constant for rate correction.
Units are nanoseconds. (Requires version 2.0 firmware.)
mca_par("reset") - Sends the command to
reset the Mythen to the default settings. (Requires version 2.0
firmware.)
mca_par("alloc_limit" [,
frames]) - Returns or sets the
maximum number of frames to store in addition to the storage used
when the
"array" option is set (to avoid redundant
memory allocation).
mca_par("verbose", [0|1]) - Returns or sets
the verbose flag. When set, spec will display
an updated frame count when acquiring multiple frames.
mca_par("flush") - Flushes the sockets
associated with the connection to the Mythen. This command
should not be needed under normal operation.
mca_par("dump") - Displays the current
values of the Mythen parameters. The following example assumes
version 2 firmware:
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Dectris Mythen 1K SN055
Settings type ("settings"): StdCu
Preset time ("preset"): 1 sec
Bits per channel ("bits"): 24
Frames ("frames"): 1
Array for data ("array"): -none-
Autocorrect ("autocorrect"): disabled
Alloc. limit ("alloc_limit"): 100 frames
Verbose ("verbose"): disabled
Delay before ("delbef"): 0 sec
Delay after ("delafter"): 0 sec
Gate ("gateen"): disabled
Gates per frame ("gates"): 1
Trigger ("trigen"): disabled
Trigger repeat ("conttrigen"): disabled
Threshold ("threshold"): 6.64962 keV
Input polarity ("inpol"): falling edge (0)
Output polarity ("outpol"): active high (0)
Bad channel interpolation ("badchan"): disabled
Rate correction ("ratecor"): disabled
Dead time constant ("tau"): 170 nsec
Auto-run mode ("auto_run"): Off (0)
Soft-preset ("soft_preset"): Off (0)
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Note, the parameter values are those spec will
use the next time it starts the Mythen. The values may differ
from those currently existing on the Mythen device.
mca_par("send", string)
- Sends the contents of
string to the
Mythen. (Normally not used, available for debugging.)
mca_par("read", string)
- Sends the contents of
string to the
Mythen and returns the integer response. (Normally not used,
available for debugging.)
SEE ALSO
mca
www.dectris.com
pymca.sourceforge.net
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Last Updated 12/13/10
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