HIGH ENERGY GAMMARAY SPECTROMETER NATALYA2 FOR SATELLITE MISSION

HIGH ENERGY GAMMA-RAY SPECTROMETER NATALYA-2 М FOR SATELLITE MISSION CORONASPHOTON Principal Investigator: Yu. D. Kotov Designers: V. N. Yurov, V. T. Samoilenko, A. I. Arkhangelsky, A. S. Glyanenko, V. V. Kadilin, E. E. Lupar, I. V. Rubtzov Moscow Engineering Physics Institute (State University), Russia Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 1

¢ The high-energy radiation spectrometer "Natalya - 2 М" is a part of a complex of scientific instrumentation of a satellite "CORONAS-PHOTON" and is developed within the bounds of the Federal space program of Russia on fundamental space investigations. ¢ "Natalya - 2 М" is designed for realization of following measurements: § studying of time behavior of intensity and energy distributions of solar and space hard electromagnetic radiation in a wide energy range from 0, 3 to 2000 Мe. V; § registration of solar neutrons in the energy range of 20 – 300 Me. V. ¢ "Natalya - 2 М" includes registration block, data handling and output systems and high voltage supply block. Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 2

Structure & main parameters Registration block structure Block name Geometry, mm Spectrometer SE-1 M 680 x 175 ~80 Spectrometer SE-2 M 680 x 175 ~80 Anticoincidence dome AK Ø 927, h=525 45 Plane anticoincidence detector AC Ø 828, h=170 17, 5 Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON Weight, kg 3

Registration modes Main performances of the spectrometer “Natalia - 2 М” Channel Structure & main parameters R (Roentgen) L (Low gamma) M (Medium gamma) H (High gamma) N (Neutrons) Energy range, Me. V Effective area, сm 2 Energy resolution, ∆Е/Е Time of accumulation Roentgen and gamma - radiation 0, 3 -2 920 10% (662 Кe. V) measured 1 -10 900 5% (2, 5 Мe. V) measured 7 -200 800 6% (10 Мe. V) calculated 100 -2000 750 32% (500 Мe. V) calculated Neutrons 20 -300 37 -120 - 1 s 1 s 1 s -* -* *- Energy and time for each event with 1 ms accuracy of binding is registered Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 4

Structure & main parameters Features of the device "Natalia-2 M" to which the attention in the report is paid: ¢ 1. Modular structure of the device ¢ 2. Stabilization system of detecting block parameters ¢ 3. System of energy scale calibration of the device during experiment ¢ Also results of working off of the module of the spectrometer which characteristics in many respects are defining for the device as a whole will be presented Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 5

Multicrystal structure Modular structure ¢ - Possibility of registration of gamma radiation in a wide dynamic range from 0, 3 to 2000 Мэ. В ¢ - Improvement of a parity of useful and background events, possibility to use the individual analysis of the information from each section and their various combinations at allocation of solar flares ¢ - Reduction of probability large energy-releases in the detector ¢ - Improvement of frequency characteristics of the device (processing of signals of each channel by separate ADC) Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 6

Multicrystal structure Spectrometer SE Designations: МА 1÷МА 4 and МВ 1÷МВ 4 - modules of layers A and B accordingly; D 1 А 1÷D 2 А 4 and D 1 В 1÷D 2 В 4 – PMT potential dividers PU 1 А 1÷PU 2 А 4 and PU 1 В 1÷PU 2 В 4 – preliminary amplifiers SUM-A and SUM-B - boards of adders of layers A and B accordingly; ST-A and ST-B - boards of stabilisation; GIT - board of current impulses generators; LED 1 А, LED 2 А, LED 1 В and LED 2 В light-emitting diodes of stabilisation system; DBSD - discriminator (provides formation of signals from BSD); DSh – control signal decoder (for operating modes of electronic units SE 1 М (SPI)). Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 7

Table of trigger algorithms Channel (energy band) R Multicrystal structure L M H Notes Measured Restriction First Second Third Fourth Anticoinci quantity of W layer (A) layer (B) layer (C) layer (D) dence (W) (Me. V) energy restriction n (Me. V) W=EA 1; EC>0, 3; EA 2; 0, 3<W<2 EC>1*; EA 3; АК and EA 4. АС** ED>0, 3; W=EA+ 0, 3<W<10 ED>1*; EB EA+EB+ АК and EC<15 АС** W=EA+ W<200 EA or ED<60 АК** EB+EC+ EB>5 ED W>70; W=EA+ coinciden- 5<EA< EB>15 EC>5 ED>5 АК** EB+EC+ ce A*B*C 200 ED or B*C*D * - Energy threshold can be changed through SPI channels (1024 values); ** - Energy threshold can be changed by single commands (2 values for АК and 2 for the AC) or through SPI channels (1024 values), cutout of an interdiction separately for АК and AC is possible. Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 8

Stabilization system Stabilization System of gain stabilization The stabilization system allows to compensate influence on PMT multiplication factor of following factors: ¢ Influence of detector loading change ¢ Influence of external magnetic fields ¢ Effects of PMT "ageing" Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 9

Stabilization System Stabilization scheme DAC - Digital-Analog Converter GIT - The Generator of Current Impulses LED - Light-emitting Diode PU - Preamplifier ST - Board of Stabilization Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 10

Stabilization Results Stabilization System Measurements of stabilization system effectiveness tuning were spent with use of the technological sample of a spectrometer and reference gamma sources set. Stabilization OFF Stabilization ON Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 11

In-flight calibration system Calibration System ¢ - possibility of calibration of a spectrometer power scale during flight experiment ¢ - possibility of compensation of long-term degradation of stabilization system light-emitting diodes properties (luminosity reduction) and scintillation crystals Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 12

Calibration System BSD scheme & placing Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 13

Separation of calibration lines Calibration System Configuration of measuring stand. Cobalt irradiates a face side of the module Background spectrum. Coincidence with BSD signal is switched-off Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 14

Separation of calibration lines Calibration System Spectrum of detector signals in coincidence with “tagging” BSD signals. Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 15

Scintillation Module Results Some results of works with the separate SE module Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 16

and 137 Cs Scintillation Module Results 60 Co Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 17

and calibration line Scintillation Module Results 22 Na Spectrometer NATALYA-2 M. Satellite CORONAS-PHOTON 18