MIRHES (Mid-IR high-resolution echelle spectrometer) MIRHES team

Outline MIRHES is a high dispersion spectrometer based on immersion grating. It has two channels for short wavelength region and long wavelength region. These two channels are completely independent from each other.

Scientific Objectives/Targets & Required Specifications

Scientific Targets

Consistency with MRD 2.3 Life Cycle of Interstellar Dust Objective #2: Dust and Molecular Shells around Low- and Intermediate-mass Stars examine the properties of molecules in MOLsphere of redgiant Objective #3: Dust formation and grain growth in Dense Molecular Clouds examine the properties of molecules in dense molecular clouds and their chemical evolution including the formation of icy mantles onto the dust grains 2.4 Studies of Exoplanets and Solar Systems Objective #2: Dissipation of Gas from Proto-planetary Disks Explore the gas at intermediate radii from the star (i.e., 1-30 AU), the key zone for understanding planet evolution MIRHES would be sensitive to the profiles of various emission lines, leading to the determination of physical/chemical conditions as a function of radius. To facilitate this, its spectral coverage is designed to observe a variety of emission lines (CO, H2O, HCN, CO2, C2H2 etc.) at 4-8 and  m. This would allow us to observe how the structure of gas disks evolve due to planet formation.

Specification of Instrument Short(S)-modeLong(L)-mode Wavelength coverage 4 – 8  m12 – 18  m Spectral resolution (R= /  30,00020,000 – 30,000 Slit width0.72”1.20” Slit length3.5”6.0” Dispersion element ZeSe immersion grating KRS5 immersion grating Cross disperserReflectivereflective

Concept Study Current Status

Optics & Volume (S) S-mode The light from the slit enters to the immersion grating through the collimator lenses. The dispersed light goes through the collimator lenses again, then collimated by the relay optics. This relay optics makes a pupil image on the cross-disperser, resulting in the small size of the entire optical system. S-mode requires two cross-dispersers to cover the entire 4-8  m range. The cross- dispersed light enters to the detector through the camera optics. The size of the entire optical system is about 200mm(L)X200mm(WW)X100mm(H).

Optics & Volume (L) L-mode Similar optical layout as for S-mode (Fig.2). Only one cross-disperser is required to cover the entire wavelength range (  m). The size of the entire optical system is about 350mm(L)X350mm(W)X200mm(H).

Optical Elements Achieved Spec for SPICA ZnSe grating < 0.2λ< < 0.2μm< 1μmEdge 3.6nm (rms)‏< 10nm (rms)‏Groove Random errors 1.8nm< 10nmGroove Periodic errors 5nm (rms)‏< 15nm (rms)‏Surface roughness AchievedTarget Grating Efficiency > 70-80% ⇒ Technical goal achieved for ZnSe

Detectors Si:As 2kx2k (Raytheon) Each arm has own detector, total 2 chips 2048 x 2048 pixel fomat Pixel pitch; 25um/pix Dark current; 0.1e/sec (TBM) Full well; 1.0x106 (electron/pix) Thermal output; 1mW Quantum Efficiency; N/A

Thermal Design

Expected Performance

Resource Requirements

Field-of-View Requirement MIHES share the fore-optics of MIRACLE FOV is 0.72 x 3.5 arcsec for S-arm and 1.20 x 6.0 arcsec for L-arm FOV should be allocated besides MIRACLE FOV.

Thermal & Cryogenic Requirement

Pointing / Attitude control Requirement

Structural Requirement

Data Generation Rate & Data Handling Requirement

Warm Electronics

Operation & Observing Mode

Development and Test Plan

Key Technical Issues & TRL

Development Plan

Test & Verification Plan

Development Cost

Observing Program

Observation Plan to perform Science Targets

Outline of Ground Data Processing

Organization & Structure for Development

Summary