We found a strange behaviour of our ADC gates for the x-ray detectors.
The setting as shown in the foto below corresponds to a delay of 5 us and a gate length of 15 us.
This is the only setting that produces nice spectra, even though the signals and gate are not aligned.
The setting is extremely sensitive to the delay 4 us still works but 3 or 7 us give already reduced energy values and beyond these values the spectra disapears.

For now it was decided to operate with this not-understood settings because the result is pretty good...
However, further investigation to understand whats happening would be desirable.

Additional note:
This effect appeared after using the new ortec SpecAmps. Before this we used old Tennelec Amps which delivered horrible resolution, but the gates and signals could be matched as expected at this time.

We are now using new SpecAmps for the x-ray detectors from ORTEC, they deliver much improved resolution but have other strange effects as discribed in the next entry.

measurement with old tennelec specAmps, do not use for efficiency!

Detector: 145
Source: B133 high rate
Distance: 305mm
Start time: 15:10:15 15.03.2020
Stop time:  15:31:16 15.03.2020

file name: run035_xxxx.lmd
avrg. rate: 1kHz
dead-time:  12%

measurement with old tennelec specAmps, do not use for efficiency!

The source moved during the calibration, measurement stopped at half time.

Detector: 145
Source: B133 high rate
Distance: 305mm
Start time: 14:54:47 15.03.2020
Stop time:  15:06:53 15.03.2020

file name: run034_xxxx.lmd
avrg. rate: 1kHz
dead-time:  11%

measurement with old tennelec specAmps, do not use for efficiency!

Detector: 145
Source: Am-241
Distance: 305mm
Start time: 14:15;56 15.03.2020
Stop time:  14:40:21 15.03.2020

file name: run033_xxxx.lmd
avrg. rate: 300Hz
dead-time:  4%

measurement with old tennelec specAmps, do not use for efficiency!

Detector: 90
Source: Ba-133 weak source
Distance: 167.5mm
Start time: 13:39:30 15.03.2020
Stop time: 13:50:55 15.03.2020

file name: run032_xxxx.lmd
avrg. rate: 150Hz
dead-time:  1.5%

measurement with old tennelec specAmps, do not use for efficiency!

Detector: 90
Source: Ba-133 strong source
Distance: 167.5mm
Start time: 13:28:42 15.03.2020
Stop time:13:38:16 15.03.2020

file name: run031_xxxx.lmd
avrg. rate: 2.7kHz
dead-time:  25%

measurement with old tennelec specAmps, do not use for efficiency!

Detector: 90
Source: Am-241
Distance: 167.5mm
Start time: 13:06:55 15.03.2020
Stop time:  13:24:57 15.03.2020

file name: run030_xxxx.lmd
avrg. rate: 650Hz
dead-time:  7%

Here you can find the digital version of the E127 beam time manual.

• r4l-58 - VME cpu (RIO)
  our DAQ runs on this computer
  access from lxg1275 via ssh litv-exp@r4l-58
  the current DAQ directory is /esr/usr/litv-exp/2020_e127/r4l-58
  from lxg-machines the DAQ dir can also be accessed via the mount point at /lynx/Lynx/esr/usr/litv-exp/2020_e127/r4l-58
  
  
• lxg1275 - main DAQ handler
  used for communication with the DAQ and primary data writing/streaming
  access from any lxg via ssh litv-exp@lxg1275
  primary data folder: /data.local3/e127/lmd/
  local backup folder: /data.local2/e127/lmd_backup/
  
  
• lxg1299 - online monitoring
  used for the R3Broot online monitor server
  access from any lxg via ssh litv-exp@lxg1299
  online data: /data.local3/e127/online/
  
  
• atpnu004 - slow control
  used for remote access to SpecAmps (MesyTec Shapers), Si-HV (caen) and picoscopes
  access from any lxg via E127_nuc or ssh litv-exp@atpnuc004
  screen sessions: mesy_ioc (shapers), caen_ioc (Si HV)
  access screens by screen -x mesy_ioc or screen -x caen_ioc (exit with [Ctrl-a d])
  access vnc session for picoscopes on any lxg: E127_vnc or vncviewer atpnuc004:1
  
  
• apraspi001 - slow control 2
  used for remote access to the BaF HV crate
  access from any lxg via ssh litv-exp@apraspi001
  local access to HV control by telnet: telnet 169.254.93.160 1527
  
  
• lxg0188 - 1st backup node
  used for direct backup of the written data (invoked automatically by stopping a run)
  backup dir: /data.local2/E127_lmd/
  
  
• kronos.hpc.gsi.de - 2nd backup node
  used for secondary backup of lmd-data on lxg0188 (chronjob every 4 hours)
  backup dir: /lustre/ap/litv-exp/2020-03-17_E127_jglorius
  

• E127_daq or /data.local1/e127/scripts/E127_start_gui.sh
  this is the GUI to control the DAQ
  available on lxg1275 only with litv-exp user
  only one instance of this GUI can run at the same time!
  
  
• E127_unpack or /u/litv-exp/unpacker/unpackexps/e127/e127
  this is the unpacker for the current DAQ
  available on any lxg with litv-exp user
  to unpack lmd-files to root-file: E127_unpack infile01.lmd infile02.lmd --ntuple=RAW,outfile.root
  
  
• E127_epics or epicsfind; medm -x /u/litv-exp/e127/medm/e127.adl
  this is the GUI for slow control of Si HV and amplifiers (MesyTec Shapers)
  available on any lxg with litv-exp user
  
  
• E127_rates or /u/litv-exp/e127/UDP/build_cc_x86_64-linux-gnu_4.9.2_debug/udp_reader --trig --rate
  this is the UDP reader for detector and trigger rates
  available on lxg1275 only with litv-exp user
  
  
  
  
  
  

The BaF2 detectors planned to be installed at the target induce an additional background in the x-ray detectors sitting below inside the target chamber. 
We made test measurements with an x-ray detector for estimating the background in the region of interest for our K-REC measurements (35 to 50 keV).

For the interval [35-50 keV]:
Normal background level: 0.065 (s*keV)^-1
BaF2 in 5cm distance:    0.078 (s*keV)^-1
This is an increase by about 22%

Assuming an increase by 100% induced by 6 BaF2 in the vincinity of the Ge-detectors this seems acceptable.

However additional BaF-induced peaks are also visible at ~30 keV and ~60 keV. While these are not in the region of interest for the K-REC, we need to be aware of them!

spectra are available on the Frankfurt exp-astro Server at /home/glorius/e127/

To find a good Si position, we need to follow a procedure similar to this:

1. Si in max-in position
2. find distance of beam by scraping with detector from inside 
--> zero position
3. from this zero, we need to set a distance of about 1.5 cm to the inside (as shown in the sketch below)

It is likely that this position is not compatible with the complete ESR cycle (e.g. we scrape beam with det. during deceleration).
The solution is to move the beam closer to the detector after deceleration. There are two feasible methods to do this:

A. make a local bump in the dipole
--> check new zero and det. position again, as sketched above
--> in 2016 this method didn't allow to go close enough to the detector, eventually we used:

B. global orbit change (by magnet ramp) + target bump (to keep overlap)
--> this takes a bit more time to set up and also the cycle will be longer at low energies (critical due to life-time)
--> method A is preferred, but might not be strong enough

This needs to be checked and repeated for each new beam setting.

https://docs.google.com/spreadsheets/d/14m8WcCq1erx6HqWJRK7TLbCx121IkjqGa5l-frf4YjI/edit#gid=0

with these HV values the 6 channels are roughly gain matched, such that the 7.83 MeV Po-decay is around channel 5000.

This is a brief how-to about getting the DSSSD set up with stored beam and target in the ESR.

The main goals
1. adjust timing signals to TDC-range
2. adjust energy signals to ADC-range
3. optimize energy resolution

The signal chain is the following:

det [32ch.] > preamp [2x16ch] > 2x MSCF shapers [16ch]

To move the detector remotely from the HKR:
-go to a desktop of a HKR computer
-right click: "App Launcher PRO"
(-you have to give some password at this point?)
-within the program go to "Development->ProHelper"
-write the name of our slow control unit in the field Nomen: "GE01DD4AS"
-There are 4rows, the middle two called: "Read props", "Write props"

-In "Read props" open "rposiabss" -> if you hit here the refresh button it will show only the SET position
-In "Read props" open "rposiabsi" -> if you hit here the refresh button it will show the REAL-TIME position of the detector

-In "Write props" open "wposiabss" -> here you can set the absolute position of our detector (one click is already enough to execute the command).
 most OUT of the ring  position: -10613 [0.1mm] in absolute
 most IN into the ring  position: -7 [0.1mm] in absolute
 The value can have as big step size as we want contrary to relative movement, when you are limited to something like 20cm.

To close the program just simply hit the "x" buttons.