Instrument rotators provide high accuracy instrument rotation at a commanded angle to ensure telescope pupil tracking. Structural support and mechanical interfaces must be provided and services (electrical and communications subsystems) routed from the stationary platform to the rotating platform for heavy instruments (which can exceed 1,500 kg). Cannot transmit vibrations to instruments. The experience gained over the years in working with several types of rotators is summarized in this paper. Not only experimental methods, but also mechanical and control models have allowed us to understand the system in depth. The paper focuses on rotators with two servomotors working together to counteract backlash and rotators with directly coupled motors. For the latter, balanced and unbalanced loads are studied. The mechanical model used to control the servo is explained and analyzed. During the development of the study, different rotator work schedules will be investigated. Tracking will be the focus of the study. The HARMONI rotator and the QUIJOTE telescopes (telescopes built by the Spanish company IDOM) in operation at the Teide Observatory (Tenerife) will therefore be the focus of our attention.
GRANCAIN (GRAN CAmara INfrarroja) is a first-light imaging instrument in the infrared J, H and K bands that will be integrated into the adaptive optics focus of the Gran Telescopio de Canarias. The purpose of the instrument is to capture SWIR diffraction-limited images for a field of view of 22x22 arcsec. The instrument boasts a telecentric optical design with a collimator-camera configuration featuring a 2:1 magnification ratio. Housed within a 160-liter aluminum cryostat, its optical path includes a cold stop, a filter wheel, and a 4Mpx Hawaii-2 PACE Teledyne detector, meticulously engineered for operation at 77K. The optics is held in place by black anodized 6061-T6 aluminum supports. These mounts serve the critical purpose of precisely positioning the optics along the Z optical axis. The opto-mechanical frames contain adjustment elements in five degrees of freedom (all except the clock) for optical alignment and to compensate the thermal differential contractions that occur during the cooling-down process. Additionally, the lens-housing cell combines different geometries and materials with different coefficients of thermal expansion to avoid stresses on the glass so as not vary its relative position. A symmetrical and athermalized opto-mechanical design, free of residual stresses, helps to minimize the deviations of the optical axis and thus facilitates the iterative process of optical alignment in cryogenic conditions. A strict manufacturing and metrological control process were necessary in order to achieve the objectives for optimum image quality. The article contains a detailed description of the design, fabrication techniques, metrology, integration, alignment, and testing of the athermalized opto-mechanical elements.
Additive Manufacture (AM) comprises a group of technologies that allow to go from a 3D model to manufactured components, creating them layer by layer until the part is complete [1]. Among the advantages of AM, the ones that apply most to astronomical instrumentation are part complexity and consolidation, the addition of functionalities, design freedom and lightweighting capability.
The IAC participated in the H2020 international consortium, within the work package on cooled mirrors for astronomical instrumentation [2], whose completion in 2021 left a series of outputs in terms of preferred technologies and materials, lightweight typologies and a cookbook [3] that includes both design guidelines for additive manufacturing and specific values of the geometrical parameters for the parts to be "printed".
The aim of this paper is to present the whole process since the beginning: from the conceptual design, to the results of the studies carried out on the lightweight mirror samples (with the two typologies and the most promising materials of those studied within the IAC for H2020). Comparisons will be made mainly in terms of metrology, dimensional tolerances and optical surface finishes of the mirrors (roughness, SFE, etc.).
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450 nm to 2450 nm with resolving powers from 3500 to 18000 and spatial sampling from 60 mas to 4 mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews. HARMONI is a work-horse instrument that provides efficient, spatially resolved spectroscopy of extended objects or crowded fields of view. The gigantic leap in sensitivity and spatial resolution that HARMONI at the ELT will enable promises to transform the landscape in observational astrophysics in the coming decade. The project has undergone some key changes to the leadership and management structure over the last two years. We present the salient elements of the project restructuring, and modifications to the technical specifications. The instrument design is very mature in the lead up to the final design review. In this paper, we provide an overview of the instrument's capabilities, details of recent technical changes during the red flag period, and an update of sensitivities.
We present here the preliminary design of the RIZ module, one of the visible spectrographs of the ANDES instrument. It is a fiber-fed high-resolution, high-stability spectrograph. Its design follows the guidelines of successful predecessors such as HARPS and ESPRESSO. In this paper we present the status of the spectrograph at the preliminary design stage. The spectrograph will be a warm, vacuum-operated, thermally controlled and fiber-fed echelle spectrograph. Following the phase A design, the huge etendue of the telescope will be reformed in the instrument with a long slit made of smaller fibers. We discuss the system design of the spectrographs system.
We present the design of the ANDES UBV module, the bluest spectrograph of the ANDES instrument. It is a fiber-fed high resolution, high stability spectrograph, which will be installed on the ELT-Nasmyth platform to minimize blue fibre losses from the focal plane to the spectrograph. In this paper we present the status of development of the spectrograph, its optical design, and auxiliary devices like exposure meter and leveling system, at the preliminary design stage. As stability is the prime design driver, a thermal enclosure is provided to keep temperature of the optical train stable at ambient conditions, and the pressure is kept constant at high vacuum level. The science, sky background and simultaneous calibration light is fed to the spectrographs via fiber bundles of 66 fibres, which are arranged in a straight row forming the spectrograph slit.
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 470nm to 2450nm with resolving powers from 3300 to 18000 and spatial sampling from 60 mas to 4 mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews. The IAC, as an institution participating in the consortium responsible for the design and manufacturing of HARMONI, is in charge of the pre-optics system. This large-scale subsystem requires a cryogenic test bench capable of accommodating it. At this point, the HIPOTEC cryostat comes into play. A Beckhoff PLC automates this large-scale cryostat. A Touchscreen panel or web browser carried out the operation, allowing for remote control. This system utilizes the TwinCAT PLC HMI Web Server. This PLC automates all the control processes of the cryostat, allowing the cryogenic cycle to perform automatically with just one click. It carries out this entire process safely using a state machine capable of bringing the system into operation.
The QUIJOTE (Q-U-I JOint TEnerife) experiment combines the operation of two radio-telescopes and three instruments working in the microwave bands from 10 to 47 GHz at the Teide Observatory, Tenerife, which has already been presented in previous SPIE meetings. The new Multi Frequency Instrument (MFI2) led by the Instituto de Astrofísica de Canarias (IAC) aims to characterize the polarized emission of the Cosmic Microwave Background (CMB), as well as Galactic and extra-Galactic sources, at medium and large angular scales. This instrument has five polarimeters, three working in the microwave band of 10-15 GHz, and two working in the microwave band of 15-20 GHz. The instrument is composed of a cylindrical aluminum 6061-T6 cryostat cooled by a closed Gifford-McMahon helium cycle cryocooler with two stage shields (first stage at 30 K, and second stage at 10 K). The opto-mechanical system consists of five horns aligned with the focal plane of the telescope where the signal enters the instrument, each horn is followed by an OMT, a 90º Hybrid and two LNAs cooled down below 20 K, all of which represents the Front-End Module (FEM). This signal leaves the instrument by a feedthrough where the Back End Module (BEM) waits at room temperature to process the signals.
The RIZ & UBV visible spectrographs of the ANDES instrument, which are foreseen to be installed at the Extremely Large Telescope, require to be under a very stable high vacuum and at an extremely stable temperature of 1mK to reach the radial velocity goal of 10cm/s RMS over a 10-year period. The baseline design, integration and first analyses of the 5.5t aluminum vacuum tank, vacuum system, and the thermal enclosure of the two-room temperature spectrographs are presented in this paper. A very analogous configuration is proposed for both instruments in view of their similarities. In addition, this article addresses the finite rigidity of the Nasmyth platform and its consequences on the instrument design together with a potential collaborative multi-CAD Product Design Management platform description.
The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs ([U]BV, RIZ, YJH) providing a spectral resolution of ∼100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 μm with the goal of extending it to 0.35-2.4 μm with the addition of an U arm to the BV spectrograph and a separate K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Modularity and fibre-feeding allows ANDES to be placed partly on the ELT Nasmyth platform and partly in the Coudé room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of almost 300 scientists and engineers which include the majority of the scientific and technical expertise in the field that can be found in ESO member states.
The Gran Telescopio de Canarias Adaptive Optic System (GTCAO) is built to provide nearly diffraction-limited images to GTC. GRANCAIN (GRAN CAmara INfrarroja) is the first light cryogenic imaging instrument in J, H, and K infrared bands, which will be integrated into the Nasmyth focus of GTCAO. The instrument is designed to image the NIR (NearInfrared) diffraction limit for a field of view of 22x22 arcsec operating up to conditions of 1.5 arcsec and zenithal distances up to 60 deg. The instrument has a telecentric optical design based on a collimator camera with a 2:1 magnification, with a cold stop, and the filters between with an infrared detector everything inside the cryostat for operating at 50 K. This article presents a comprehensive overview of the end-to-end optical design of GRANCAIN. It explores the selection criteria for diverse commercial elements, conducts thermal analysis utilizing Ansys Zemax OpticStudio, and delineates the acceptance tests performed at the IAC. The article also encompasses tolerance analysis using Ansys Zemax OpticStudio and establishing the error budget. Furthermore, the text provides a detailed account of the alignment process, achieved through the mechanical positioning of each optical element with a laser tracker and the confirmation of positions under cryogenic conditions is conducted using an alignment telescope. Lastly, the article discusses the optical acceptance plans for the instrument before its integration into GTCAO.
The QUIJOTE (Q-U-I joint Tenerife) experiment combines the operation of two radio-telescopes and three instruments working in the microwave bands 10–20 GHz, 26–36 GHz and 35–47 GHz at the Teide Observatory, Tenerife, and has already been presented in previous SPIE meetings (Hoyland, R. J. et al, 2012; Rubi˜no-Mart´ın et al., 2012). The Cosmology group at the IAC have designed a new upgrade to the MFI instrument in the band 10–20 GHz. The aim of the QUIJOTE telescopes is to characterise the polarised emission of the cosmic microwave background (CMB), as well as galactic and extra-galactic sources, at medium and large angular scales. This MFI2 will continue the survey at even higher sensitivity levels. The MFI2 project led by the Instituto de Astrof´ısica de Canarias (IAC) consists of five polarimeters, three of them operating in the sub-band 10–15 GHz, and two in the sub-band 15–20 GHz. The MFI2 instrument is expected to be a full two–three times more sensitive than the former MFI. The microwave complex correlator design has been replaced by a simple correlator design with a digital back-end based on the latest Xilinx FPGAs (ZCU111). During the first half of 2019 the manufacture of the new cryostat was completed and since then the opto-mechanical components have been designed and manufactured. It is expected that the cryogenic front-end will be completed by the end of 2022 along with the FPGA acquisition and observing system. This digital system has been employed to be more robust against stray ground-based and satellite interference, having a frequency resolution of 1 MHz
Additive manufacture (AM), also known as 3D printing, builds an object, layer-by-layer, from a digital design file. The primary advantage of the layer-by-layer approach is the increase in design-space, which enables engineers and scientists to create structures and geometries that would not be practical, or possible, via conventional subtractive machining (mill, drill and lathe). AM provides more than prototyping solutions: there are a broad range of materials available (polymers, metals and ceramics); software capable of creating lightweight structures optimised for the physical environment; and numerous bureaux offering AM as a service on a par with subtractive machining. In addition, AM is an ideal method for bespoke, low-count parts, which are often the foundation of astronomical instrumentation. However, AM offers many challenges as well as benefits and, therefore, the goal of the OPTICON A2IM Cookbook is to provide the reader with a resource that outlines the scope of AM and how to adopt it within astronomical hardware, with an emphasis on the fabrication of lightweight mirrors. The Cookbook was an open access deliverable of the EU H2020 funded OPTICON (Optical Infrared Coordination Network for Astronomy; grant agreement #730890) A2IM (Additive Astronomy Integrated-component Manufacturing; PI H. Schnetler) work package and it was completed in June 2021. This paper will introduce the Cookbook, its scope and methodology, and highlight the paradigm shift required to design and AM lightweight mirrors for astronomy and space-science.
HARMONI is the first light, adaptive optics assisted, integral field spectrograph for the European Southern Observatory’s Extremely Large Telescope (ELT). A work-horse instrument, it provides the ELT’s diffraction limited spectroscopic capability across the near-infrared wavelength range. HARMONI will exploit the ELT’s unique combination of exquisite spatial resolution and enormous collecting area, enabling transformational science. The design of the instrument is being finalized, and the plans for assembly, integration and testing are being detailed. We present an overview of the instrument’s capabilities from a user perspective, and provide a summary of the instrument’s design. We also include recent changes to the project, both technical and programmatic, that have resulted from red-flag actions. Finally, we outline some of the simulated HARMONI observations currently being analyzed.
A possible answer to the challenge brought by the construction of the next generation 40 m-class telescopes was the case study of FAME (Freeform Active Mirror Experiment). As the new instruments typically increased in both volume and complexity, the use of highly aspherical freeform surfaces could be a great solution as these systems are built up from fewer parts and can achieve higher performance. The idea of FAME was to create a thin face sheet which is then deformed to the nominal shape utilizing actuators mounted on the back of the mirror and acting parallel to the optical surface. The test phase of the FAME prototype revealed the complexity of the design and its sensitivity to manufacturing and assembly processes. As part of the characterization it was very difficult to predict correctly how the system behaves which is due to the several interfaces between the actuators and the face sheet. These experiences led to the development of a new structure that eliminates the strict tolerance chain obtained from a variety of components mounted on one another. It also means that the design for conventional manufacturing technologies should be left behind, and additive manufacturing must be introduced. This paper gives a brief overview how the lessons learned from the previous development is matched with the new design approach of the same component using topology optimization, additive manufacturing of metals and post processing of 3D printed parts. This work is funded under the OPTICON H2020 INFRAIA-2016-2017/H2020-INFRAIA-2016-1 Grant Agreement 730890.
Additive Manufacturing (AM; 3D printing) for mirror fabrication allows for intricate designs that can combine lightweight structures and integrated mounting. Conventional lightweight structures utilise cubic or prismatic unit cells, which do not provide uniform support at the edge of curved mirrors. We present a new circular lattice based upon cylindrical coordinates and how this lattice has been incorporated within an 80 mm diameter mirror intended for use in a 3U CubeSat telescope. Several design iterations are explored, which include prototype mirrors produced in a titanium alloy and a finite element analysis of the one of the design iterations.
Additive manufacturing (AM) offers many advantages, including material savings, lightening, design freedom, function integration, etc. In the case of cellular materials, regular structures (lattice and honeycomb) are particularly important due to their ability to reduce weight. However, the design process and FEM analysis of this type of structure is very high time-consuming. In order to mitigate this problem, we propose a modelling method, called "Equivalent Continuum Material", based on the treatment of a cellular material as a continuous mass. This document describes the method and presents examples of applications, to facilitate and understand its use.
Additive manufacturing (AM) methods and post processing techniques are promising methodologies considering that it is now possible to print in a wide variety of materials using processes much refined from those originally available twenty years ago. To date the uptake of AM in Astronomy is relatively low compared to other application areas, aviation being one such example. Due to the rapid progress made in additive manufacturing and the lack of its adoption in Astronomy, there are many opportunity to deploy new fabrication processes. In this paper, we outline the project and report the results of our investigation to make use of additive manufacturing and novel materials in the fabrication of multi-functional integrated components fit for use in astronomy instrumentation, which can operate in cryogenic environments and space application.
In this paper we are exploring the possibilities of 3D printing in the fabrication of mirrors for astronomy. Taking the advantages of 3D printing to solve the existing problems caused by traditional manufacturing, two proof-of- concept mirror fabrication strategies are investigated in this paper. The first concept is a deformable mirror with embedded actuator supports system to minimise errors caused by the bonding interfaces during mirror assembly. The second concept is the adaption of the Stress Mirror Polishing (SMP) technique to a variety of mirror shapes by implemented a printed thickness distribution on the back side of the mirror. Design investigations and prototypes plans are presented for both studies.
The QUIJOTE Experiment (Q-U-I JOint TEnerife) is a combined operation of two telescopes and three instruments working in the microwave band to measure the polarization of the Cosmic Microwave Background (CMB) from the northern hemisphere, at medium and large angular scales. The experiment is located at the Teide Observatory in Tenerife, one of the seven Canary Islands (Spain). The project is a consortium maintained by several institutions: the Instituto de Astrofísica de Canarias (IAC), the Instituto de Física de Cantabria (IFCA), the Communications Engineering Department (DICOM) at Universidad de Cantabria, and the Universities of Manchester and Cambridge. The consortium is led by the IAC.
The PLT-HPT-32, a new cryogenic temperature monitor, has been developed by the Institute of Astrophysics of the Canary Islands (IAC) and an external engineering company (Sergio González Martín-Fernandez). The PLT-HPT-32 temperature monitor offers precision measurement in a wide range of cryogenic and higher-temperature applications with the ability to easily monitor up to 32 sensor channels. It provides better measurement performance in applications where researchers need to ensure accuracy and precision in their low cryogenic temperature monitoring.
The PLT-HPT-32 supports PTC RTDs such as platinum sensors, and diodes such as the Lake Shore DT-670 Series. Used with silicon diodes, it provides accurate measurements in cryo-cooler applications from 16 K to above room temperature. The resolution of the measurement is less than 0.1K. Measurements can be displayed in voltage units or Kelvin units. For it, two different tables can be used. One can be programmed by the user, and the other one corresponds to Lake Shore DT670 sensor that comes standard.
There are two modes of measuring, the instantaneous mode and averaged mode. In this moment, all channels must work in the same mode but in the near future it expected to be used in blocks of eight channels. The instantaneous mode takes three seconds to read all channels. The averaged mode takes one minute to average twenty samples in all channels. Alarm thresholds can be configured independently for each input. The alarm events, come from the first eight channels, can activate the unit’s relay outputs for hard-wired triggering of other systems or audible annunciators. Activate relays on high, low, or both alarms for any input.
For local monitoring, "Stand-Alone Mode", the front panel of the PLT-HPT-32 features a bright liquid crystal display with an LED backlight that shows up to 32 readings simultaneously. Plus, monitoring can be done over a network "Remote Control Mode". Using the Ethernet port on the PLT-HPT-32, you can keep an eye on temperatures, log measurement and configured remotely via a Networked local PC or even remotely over a TCP/IP Internet connection from anywhere.
The QUIJOTE (Q-U-I JOint Tenerife) CMB Experiment is operating at the Teide Observatory with the aim of
characterizing the polarization of the CMB and other processes of Galactic and extragalactic emission in the frequency
range of 10–40GHz and at large and medium angular scales. The QUIJOTE CMB experiment consists of two telescopes
installed inside a single enclosure, and three instruments, the MFI (multi-frequency 10–30GHz), the TGI (26–36 GHz)
and the FGI (37–47 GHz). The first QUIJOTE telescope and the MFI instrument have been in operation at the
Observatory since November 2012. In this poster we present the TGI cryostat and optomechanics status, including their
design, MAIT, and thermal clamp developments.
KEYWORDS: Telescopes, Control systems, Polarimetry, Switches, Data acquisition, Human-machine interfaces, Polarimetry, Field programmable gate arrays, Data storage, Data communications, Safety
The QUIJOTE-CMB experiment (Q-U-I JOint TEnerife CMB experiment) has been described in previous publications.
In particular, the architecture of the MFI instrument control system, the first of the three QUIJOTE instruments, was
presented in [1]. In this paper we describe the control system architecture, hardware, and software, of the second
QUIJOTE instrument, the TGI (Thirty GHz Instrument), which has been in the process of commissioning for a few
weeks now. It is a 30 pixel 26-36 GHz polarimeter array mounted at the focus of the second QUIJOTE telescope. The
polarimeter design is based on the QUIET polarimeter scheme, implementing phase switches of 90° and 180° to generate
four states of polarisation. The TGI control system acquires the scientific signal of the four channels for each of the 30
polarimeters, sampled at 160 kHz; it controls the commutation of the 30 x 4 phase switches at 16 kHz or 8 kHz; it
performs the acquisition and monitoring of the health of the complete instrument, acquiring housekeeping from the
various subsystems and also controls the different operational modes of the telescope. It finally, implements a queue
system that permits automation of the observations by allowing the programming of several days of observations with
the minimum of human intervention. The acquisition system is based on a PXI-RT host from NI, the commutations of
the phase switches are performed by a PXI-FPGA subsystem and the telescope control is based on an EtherCAT bus
from Beckhoff.
R. Hoyland, M. Aguiar-González, R. Génova-Santosa, F. Gómez-Reñasco, C. López-Caraballo, R. Rebolo-López, J. Rubiño-Martín, V. Sánchez-de la Rosa, A. Vega-Moreno, T. Viera-Curbelo, A. Pelaez-Santos, R. Vignaga, D. Tramonte, F. Poidevin, M. Pérez-de-Taoro, E. Martínez-Gonzalez, B. Aja, E. Artal, J. Cagigas, J. Cano-de-Diego, E. Cuerno, L. de-la-Fuente, A. Pérez, D. Ortiz, J. Terán, E. Villa, L. Piccirillo, M. Hobson
The QUIJOTE TGI instrument is currently being assembled and tested at the IAC in Spain. The TGI is a 31 pixel 26-36 GHz polarimeter array designed to be mounted at the focus of the second QUIJOTE telescope. This follows a first telescope and multi-frequency instrument that have now been observing almost 2 years. The polarimeter design is based on the QUIET polarimeter scheme but with the addition of an extra 90º phase switch which allows for quasiinstantaneous complete QUI measurements through each detector. The advantage of this solution is a reduction in the systematics associated with differencing two independent radiometer channels. The polarimeters are split into a cold front end and a warm back end. The back end is a highly integrated design by the engineers at DICOM. It is also sufficiently modular for testing purposes. In this presentation the high quality wide band components used in the optical design (also designed in DICOM) are presented as well as the novel cryogenic modular design. Each polarimeter chain is accessible individually and can be removed from the cryostat and replaced without having to move the remaining pixels. The optical components work over the complete Ka band showing excellent performance. Results from the sub unit measurements are presented and also a description of the novel calibration technique that allows for bandpass measurement and polar alignment. Terrestrial Calibration for this instrument is very important and will be carried out at three points in the commissioning phase: in the laboratory, at the telescope site and finally a reduced set of calibrations will be carried out on the telescope before measurements of extraterrestrial sources begin. The telescope pointing model is known to be more precise than the expected calibration precision so no further significant error will be added through the telescope optics. The integrated back-end components are presented showing the overall arrangement for mounting on the cryostat. Many of the microwave circuits are in-house designs with performances that go beyond commercially available products.
Experiment QUIJOTE (Q-U-I JOint TEnerife) is a scientific collaboration, leaded by the Instituto de Astrofísica de Canarias (IAC), which can measure the polarization of the Cosmic Microwave Background (CMB) in the range of frequency up to 200 GHz, at angular scales of 1°. The project is composed of 2 telescopes and 3 instruments, located in Teide Observatory (Tenerife, Spain).
After the successful delivery of the first telescope (operative since 2012), Idom is currently involved on the turn key supply of the second telescope (phase II). The work started in June 2013 and it will be completed in a challenging period of 12 months (operative at the beginning of July 2014), including design, factory assembly and testing, transport and final commissioning on site.
This second unit will improve the opto-mechanical performance and maintainability. The telescope will have an unlimited rotation capacity in azimuth axis and a range of movement between 25°-95° in elevation axis. An integrated rotary joint will transmit fluid, power and signal to the rotary elements. The pointing and tracking accuracy will be significantly below to specification: 1.76 arcmin and 44 arcsec, respectively.
This project completes Idom´s contribution during phase I, which also comprises the integration and functional tests for the 5 polarimeters of the first instrument in Bilbao headquarters, and the design and supervision of the building which protects both telescopes, including the installation and commissioning of the mechanism for shutters aperture.
M. Pérez-de-Taoro, M. Aguiar-González, R. Génova-Santos, F. Gómez-Reñasco, R. Hoyland, C. López-Caraballo, A. Peláez-Santos, F. Poidevin, D. Tramonte, R. Rebolo-López, J. Rubiño-Martín, V. Sánchez-de la Rosa, A. Vega-Moreno, T. Viera-Curbelo, R. Vignaga, E. Martínez-Gonzalez, B. Aja, E. Artal, J. Cagigas, J. Cano-de-Diego, E. Cuerno, L. de-la-Fuente, A. Pérez, J. Terán, E. Villa, L. Piccirillo, A. Lasenby
The QUIJOTE-CMB experiment (Q-U-I JOint TEnerife CMB experiment) is an ambitious project to obtain polarization measurements of the sky microwave emission in the 10 to 47 GHz range. With this aim, a pair of 2,5μm telescopes and three instruments are being sited at the Teide Observatory, in Tenerife (Canary Islands, Spain). The first telescope and the first instrument (the MFI: Multi Frequency Instrument) are both already operating in the band from 10 to 20 GHz, since November 2012. The second telescope and the second instrument (TGI: Thirty GHz instrument) is planned to be in
commissioning by the end of summer 2014, covering the range of 26 to 36 GHz. After that, a third instrument named FGI (Forty GHz instrument) will be designed and manufactured to complete the sky survey in the frequency range from 37 to 47 GHz. In this paper we present an overview of the whole project current status, from the technical point of view.
The QUIJOTE-CMB project has been described in previous publications. Here we present the current status of the
QUIJOTE multi-frequency instrument (MFI) with five separate polarimeters (providing 5 independent sky pixels): two
which operate at 10-14 GHz, two which operate at 16-20 GHz, and a central polarimeter at 30 GHz. The optical
arrangement includes 5 conical corrugated feedhorns staring into a dual reflector crossed-draconian system, which
provides optimal cross-polarization properties (designed to be < −35 dB) and symmetric beams. Each horn feeds a novel
cryogenic on-axis rotating polar modulator which can rotate at a speed of up to 1 Hz. The science driver for this first
instrument is the characterization of the galactic emission. The polarimeters use the polar modulator to derive linear
polar parameters Q, U and I and switch out various systematics. The detection system provides optimum sensitivity
through 2 correlated and 2 total power channels. The system is calibrated using bright polarized celestial sources and
through a secondary calibration source and antenna. The acquisition system, telescope control and housekeeping are all
linked through a real-time gigabit Ethernet network. All communication, power and helium gas are passed through a
central rotary joint. The time stamp is synchronized to a GPS time signal. The acquisition software is based on PLCs
written in Beckhoffs TwinCat and ethercat. The user interface is written in LABVIEW. The status of the QUIJOTE MFI
will be presented including pre-commissioning results and laboratory testing.
The QUIJOTE-CMB experiment has been described in previous publications. Here we describe the architecture of the
control system, hardware and software, of the QUIJOTE I instrument (MFI). It is a multi-channel instrument with five
separate polarimeters: two of which operate at 10-14 GHz, two of which operate at 16-20 GHz, and a central polarimeter
at 26-36 GHz. Each polarimeter can rotate at a speed of up to 1 Hz and also can move to discrete angular positions which
allow the linear polar parameters Q, U and I to be derived. The instrument is installed in an alt-azimuth telescope which
implements several operational modes: movement around the azimuth axis at a constant velocity while the elevation axis
is held at a fixed elevation; tracking of a sky object; and raster of a rectangular area both in horizontal and sky
coordinates. The control system of both, telescope and instrument, is based in the following technologies: an LXI-VXI
bus is used for the signal acquisition system; an EtherCAT bus implements software PLCs developed in TwinCAT to
perform the movement of the 5 polarimeters and the 2 axes of the telescope. Science signal, angular positions of the 5
polarimeters and telescope coordinates are sampled at up to 4000 Hz. All these data are correlated by a time stamp
obtained from an external GPS clock implementing the Precise Time Protocol-1588 which provides synchronization to
less than 1 microsecond. The control software also acquires housekeeping (HK) from the different subsystems.
LabVIEW implements the instrument user interface.
The QUIJOTE (Q-U-I JOint Tenerife) CMB Experiment will operate at the Teide Observatory with the aim
of characterizing the polarisation of the CMB and other processes of Galactic and extragalactic emission in the
frequency range of 10-40GHz and at large and medium angular scales. The first of the two QUIJOTE telescopes
and the first multi-frequency (10-30GHz) instrument are already built and have been tested in the laboratory.
QUIJOTE-CMB will be a valuable complement at low frequencies for the Planck mission, and will have the
required sensitivity to detect a primordial gravitational-wave component if the tensor-to-scalar ratio is larger
than r = 0.05.
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