Recent development of gaseous position-sensitive thermal neutron detectors for the IBR-2 spectrometers A.V.Belushkin, A.A.Bogdzel, A.N.Chernikov, A.V.Churakov, T.L.Enik, S.A.Kutuzov, F.V.Levchanovski, Li En Che, E.I.Litvinenko, A.S.Nikiforov, Tz.Panteleev, V.I.Prikhodko, V.N.Shvetsov, V.V.Zhuravlev NEOKS FLNP JINR 2007

MWPC with delay line readout High efficiency (~80 %) High efficiency (~80 %) High count rate (~ MHz) High count rate (~ MHz) Acceptable position resolution (1.5mm) Acceptable position resolution (1.5mm) Excellent γ-background rejection (10 -8 ) Excellent γ-background rejection (10 -8 ) Two dimensional capability Two dimensional capability Long term stability (~5 yrs) Long term stability (~5 yrs) Design flexibility Design flexibility

Infrastructure Clean room Clean room – ISO Class 7 clean room Radiation stand Radiation stand – Includes Roentgen source, neutron source and electronics Wire winding machine Wire winding machine – Designed and manufactured new wire winding machine, making possible manufacturing of MWPC with active area up to 600х600 мм 2 Gas stand Gas stand Radiation stand. Photo of the operators workplace

2D monitor PSD 100x100 mm2 Direct neutron beam monitor Designed and constructed for FRM-2 (Germany)

IBR-2 measurements Spectra of the 2D monitor, measured at IBR-2 reactor Profile of the channel №10 Mask (Cd) Profile of the channel №6b Profile of the channel №10 with mask

IBR-2 measurements Profile of the IBR-2 channel №7a Profile of the channel №7a Size of the beam 50x160 мм 2 ± 4 mm 2 Average intensity ≈ 1,8 * 10 6 n/sm 2 *sec. Sum on Y-axis

1D PSD 200x80 mm 2 Multi-purpose instrument for solid-state measurements

IBR-2 measurements Diffraction spectra of the (La 0.1 Pr 0.9 ) 0.7 Ca 0.3 Mn 0.3 sample, measured at the channel №5. At low temperatures it separated at FM-metallic and AFM-CO-insulating mesoscopic phases. Spectrum of the MgO/(4.7nm)Fe/(4.7nm)V]10/[(1ML)Fe/(1ML)V]17/(36.5nm)V/(2nm)Pd multilayer sample measured at the refletometer REFLEX (channel №9) T=10˚K T=290˚K

2D PSD 225x225 mm 2 Developed with support from MinPromNauki (grant № from ) Testing are started

2D PSD 225x225 mm 2 Test measurement of 2D PSD 225x225 mm 2 Gas mix: 50 mbar 3 He+3450 mbar 4 He+1500 mbar CF 4 Anode voltage+4300 V; Drift voltage V

Electronics Scheme of the electronics Crate NIM with analog electronics Pre-amplifiers

PCI-DAQ board PCI DAQ board Two main operating modes are provided: histogram (on-line sorting of data and building of spectra) and "list" (accumulation of raw data with subsequent off-line processing). In the regime of the accumulation of histograms the effectiveness of the DAQ system is 10 5 event/s, and in the raw data mode effectiveness is up to event/s. Created in cooperation with HMI, Berlin. It comprises 8-channel TDC of F1 type (Acam), FIFOs of different types, CPLD, FPGA, 256 Mbyte histogram memory and DSP TMS 320C6711. The DAQ board has a PCI- interface and is installed directly in the case of PC.

New PCI-DAQ board Projected PCI-DAQ board A new DAQ board has been designed for 1D and 2D MWPC detectors with delay line data readout. This board contains the NIM-TTL signal level converter; 8-channel integrated time-digital converter (TDC- GPX); programmed logic matrix (FPGA) comprising about 6К of logic elements; 1Gbyte histogram memory, which makes it possible to accumulate three- dimensional spectra of size of up to 512×512×1024 of 32-digit words, and high-speed interface with an optical communication link to a personal computer. Logic and time simulation of work of the board has been performed using the Quartus II package. As a result, it has been demonstrated that the rate of data reception, filtration and accumulation in the board runs as high as 2 million events/s. Real registration rate (taking into account data transfer and recording into a computer) is no less than 1 million events/s. Now a new board is in the pilot production stage.

Software Software complex based on SONIX+ integrated in SONIX+ system integrated in SONIX+ system allows fully automates experiment allows fully automates experiment based on the Python script language based on the Python script language Software complex based on ROOT real-time data observation real-time data observation currently used for detectors testing and in BER-II reactor (together with CAERESS) currently used for detectors testing and in BER-II reactor (together with CAERESS) based on the ROOT library based on the ROOT library

Results Done: Developed and tested 2D 100x100 mm 2 monitor PSDDeveloped and tested 2D 100x100 mm 2 monitor PSD Developed and tested 1D 200x80 mm 2 PSDDeveloped and tested 1D 200x80 mm 2 PSD Developed 2D 225x225 mm 2 PSDDeveloped 2D 225x225 mm 2 PSD Planned: Finished testing of the 2D 225x225 mm 2 PSD Finished testing of the 2D 225x225 mm 2 PSD Continue equipment IBR-2 spectrometers with PSD Continue equipment IBR-2 spectrometers with PSD Further improve infrastructure in order to create large-area PSDFurther improve infrastructure in order to create large-area PSD Research and development of the individual readout system for the neutron PSD Research and development of the individual readout system for the neutron PSD