HEND physical calibrations: status report

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HEND physical calibrations status report

• A. Kozyrev, S. Charyshnikov, V. Grinkov,, M.
  Litvak,
• I. Mitrofanov, A. Sanin, V. Tretyakov
• Institute for Space Research
• V. Shvetsov, G. Timoshenko, A. Krylov
• Joint Institute for Nuclear Research

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• Schematic design of HEND

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Schematic design of sensor LD (Left) and SD
(Right) for epithermal neutrons
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Components of SD and LD sensors
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He3n?H3p Etotal Etotal 0.764 MeV E(H3) 1/4
Etotal 0.191 MeV E(p) 3/4 Etotal 0.573 MeV
ј Etotal TRITON
ѕ Etotal PROTON
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Measured spectrum of counts of MD sensor is
represented in 16 channels
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Schematic design of stilbene and CsI
scintillation detectors
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Registration of neutrons on recoil protons 
Neutron
Recoil proton
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Separation between background and recoil protons
is done by help of anticoincidence circuit based
on CsI crystal which surrounds stilbene detector
in direction of open space
Proton
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Distinguishing between neutron and gamma signal
in stilbene crystal is done by help of electronic
pulse shape in the stilbene crystal
Photon
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Performance
Energy range LD 10.0 eV -
1.0 MeV MD 0.4 eV -100.0
keV SD 0.4 eV - 1.0 keV
IN/SC/N 850 keV 15.0 MeV
IN/SC/G 60 keV 2.0 MeV OUT/SC 30 keV 1.0
MeV
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Stability spectra and temperature during mapping
18/02/2002-18/04/2002 2 month
01/04/2003-01/06/2003 2 month
10/09/2002-10/11/2002 2 month
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Stability spectra during mapping
LD
MD
CsI(Tl)
Stilbene
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Stability temperature during mapping
Second
First
Third
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-15

• t1- temperature of main electronic board
• t2- temperature of HV board
• t3- temperature of stilbene electronic board

-15 lt tHEND lt 15
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Calibration Facility
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Calibration Facility
Source of neutrons Flux 106 n cm2 /sec d(T,n)?
(15 MeV n) d(D,n) 3He (5 MeV
n) 7Li(p,n)7Be (lt 1 MeV n)
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Calibration Facility
Cf source 2.1 MeV (13.2/-0.2)/r2n cm-2 s-1
Pu-Be source 3.8 MeV (29.6/-0.2)/r2n cm-2 s-1
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Calibration measurements results
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Calibration measurements results
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Simulation response function
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HEND energy range
Response functions of LD, MD and SC/neutron
sensors allow to fit data of 2, 3 and 4
periapses with function of type ?E-?
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Using response function
Model neutron spectra on Mars orbit
Model count of HEND neutron sensor
Calculation
Response function of HEND sensors
Calculation (Pearson criteria)
Probability of aligning model
Real count of HEND neutron sensor
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• Conclusion
• During mapping, spectra of HEND sensors were
  stable
• During mapping, temperature of HEND instrument
  were lie in the range of /- 15 C
• HEND numerical model as an assembly were
  simulated for neutron LD, MD and SD sensor
• Future task
• Building of HEND numerical model with taking
  into account the spacecraft model
• Physical calibration and simulation of SC
  sensor to establishing of corresponds between
  Flight and Qualification units
• Physical calibration of HEND instrument with
  respect to gamma-rays and charge particles