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Mythen

Dectris Mythen strip (1D) detector controller

The Mythen is a 1D,strip , detector based on hybrid pixel technology made by Dectric company. It can operate at 1000Hz, 24-bit, with a readout time of 89us. Its energy range is from 4 to 40 keV (down to 4keV only for 320um x 4 mm sensors). Threshold and energy in keV can be selected.

The Mythen strip detector is commonly used as MCA-like detector in the field of spectroscopy application.

There are actually two versions of Mythen hardware, so-called Mythen and Mythen2, the BLISS controller supports both systems.

The Mythen is a networked device which can be configured for a fix IP address. An embedded web client is running in the Detector Control System4 (DCS4) box. The DCS4 is delivered from factory with IP address 192.168.0.90.

The Mythen web client can be used to test the detector, it provides a full access to the detector configuration and the acquisition.

Configuration example from ID10 EH1

- name: mythen1
  module: mca.mythen
  class: Mythen
  plugin: bliss
  hostname: mythenid101
  apply_defaults: True    # Reset all the settings to their default value, it
                            applies a reset command, see dectris manual for
                            reset values
  energy: 10              # keV
  threshold: 5            # kev

- name: mythen2
  module: mca.mythen
  class: Mythen
  plugin: bliss
  hostname: mythenid102
  apply_defaults: True
  energy: 12

Above example works in case there is a __init__.yml in the same directory containing: 

    plugin: bliss

Full list of configuration with default values

Setting Possible values Default Unit
nmodules 1-4 1 int.
delay_after_frame 0-N 0.0 sec.
nframes 1-N 1 int.
nbits 4,8,16,24 24 bit
exposure_time 1e-7-N 1.0 sec.
energy Emin-Emax (1) 8.05 keV
threshold Thrmin-Thrmax (1) 1 keV
bad_channel_interpolation True,False True bool.
flat_field_correction True,False True bool.
rate_correction True,False False bool.
rate_correction_deadtime 0-N N/A sec.
continuous_trigger_mode True,False False bool.
single_trigger_mode True,False False bool.
delay_before_frame 1e-7-N 0.0 sec.
gate_mode True,False False bool.
ngates 1-N 1 int.
input_polarity 0,1 (2) 0 int.
output_polarity 0,1 (2) 0 int.
selected_module 0-N 0 int.
element_settings Cu,Mo,Cr,Ag Cu N/A

(1) : The supported energy and threshold ranges depend on the module type, see the detector manual for the ranges.

(2) : in/out polarity change is deprecated from mythen controller model DCS4.

Sample Tricks

The mythen has low level commands for energy/threshold/correction/deadtime settings and a high level command element_settings with predefined settings for Copper, Molybdenum, Chromium or Silver tube. Changing the element_settings will apply new values for the low levet settings.

From the Mythen controller object you can display the settings in one shot: 

TEST_MYTHEN [1]: mythen2 = config.get('mythenid102')
TEST_MYTHEN [3]: mythen2 
        Out [3]: Mythen on mythenid102:
                   nmodules                  = 2
                   delay_after_frame         = 0.0
                   nframes                   = 1
                   nbits                     = 24
                   exposure_time             = 1.0
                   energy                    = (22.16, 22.16)
                   threshold                 = (11.08, 11.08)
                   bad_channel_interpolation = True
                   flat_field_correction     = True
                   rate_correction           = False
                   rate_correction_deadtime  = (1.3882828e-07, 1.3525846e-07)
                   continuous_trigger_mode   = False
                   single_trigger_mode       = False
                   delay_before_frame        = 0.0
                   gate_mode                 = False
                   ngates                    = 1
                   selected_module           = 0
                   element_settings          = ('Ag', 'Ag')

Some Mythen commands (energy, threshold, element_settings …) apply on the selected module. The DCS4 can control up to 4 modules and you can choose to select all (default) on only one. The attribute selected_module gives access to this:

TEST_MYTHEN [4]: mythen2.selected_module
        Out [4]: 0  # means all selected
TEST_MYTHEN [5]: mythen2.selected_module=2 #select module number 2
TEST_MYTHEN [6]: mythen2.element_settings='Cu' # change settings of
                                                 module #2 to Cu

TEST_MYTHEN [8]: mythen2
        Out [8]: Mythen on mythenid102:
                   nmodules                  = 2
                   delay_after_frame         = 0.0
                   nframes                   = 1
                   nbits                     = 24
                   exposure_time             = 1.0
                   energy                    = (22.16, 8.05)
                   threshold                 = (11.08, 6.4)
                   bad_channel_interpolation = True
                   flat_field_correction     = True
                   rate_correction           = False
                   rate_correction_deadtime  = (1.3882828e-07, 2.3231377e-07)
                   continuous_trigger_mode   = False
                   single_trigger_mode       = False
                   delay_before_frame        = 0.0
                   gate_mode                 = False
                   ngates                    = 1
                   selected_module           = 2
                   element_settings          = ('Ag', 'Cu')

Further reading from Dectris