NONLINEARITY INVESTIGATION AT 44 GHz USING PROTOTYPE UNITS: BEM44_B3_DC AND BEM44_B4_DC

Several tests have been performed at JBO to investigate the problem of representative FM BEM compression. Evidence of some compression happening inside the BEM is given by the high noise temperatures measured during the December test campaign, firstly on FEM 4F2 and then on FEM 4F3 when coupled to representative BEMs. JBO has four representative BEMs, two (B3 and B4) provided with diodes and then having a DC output, two (B1 and B2) without any diode and having an RF output. During last 2005 JBO tests, DC BEMs have shown to be compressed while RF BEMs have shown only a weak compression. Dedicated tests have been performed during the last test campaign to investigate the degree of compression, common features between the two BEMs, the noise temperature reachable in compressed conditions. Comparison tests have been also performed to check the repeatability of procedures used

LFI in-flight susceptibility to Front End electric instabilities: analysis of the HK over-sampling Test

Drain Currents are the unique HK parameter monitoring the electric behavior of the LFI Front End LNAs. Their importance is related with their capability to track gain changes at Front-End level induced by Gate Voltage (Vg) and Drain Voltage (Vd) changes. In fact, Vg and Vd are not measured but only indirectly known from the values set at DAE level any time the DAE actual TM packet is commanded (once pe

Electromagnetic Simulations Of WaveGuides Venting Holes

LFI waveguides may create problem in empty out the LFI front–end modules and back–end modules during the satellite launch. In order to avoid any damage of the radiometers, holes in waveguides may be necessary to facilitate the reaching of the vacuum condition in space: the air will flow mainly through these hole instead through the radiometers. Simulations have been performed at 70 GHz on a straight section of the WR12 waveguide, using the Finite Elements Method based HFSS software. This frequency is the most critical one since the hole diameter is about 2/3 of the waveguide lateral dimension. Two models will be illustrated

LSPE-StrIP: StrIP Integration procedure @ INAF-OAS

Scope of this document is to describe cryogenic harness in the StrIP LSPELSPEStrIP: StrIP Integration procedure @ INAF 2 o f STRIP79and report the OAS procedure to be used to Doc. Pag. Rev. Date 4.0 JAN 2020 RP004 integrate the StrIP Focal Plane Unit and the cryostat

ALMA B23 Cryo Chain Control Procedure

In this document, we describe the procedures to correctly operate the NAOJ Cryofacility Equipment once the cryostat is closed and sealed. The Cryostat is currently installed at the Cryowaves lab at the premises of INAF –IASFB

Analysis of Voltage Jumps In LFI18 R0D0-R0D1 and LFI26 R1D0-R1D1 and debug procedure on LFI 26 during OD204

This note was aimed at debugging the two features observed during OD 184-185 and OD 188 on channels LFI 26 and LFI18. A dedicated procedure for debugging the LFI 26 issue was also proposed, performed and analyzed in this report. The two features exhibited as Scientific Voltage jumps both on REF and SKY signals of the two coupled diodes, as reported in the table below. In the case of channel LFI 26 the signal increased suddenly on both sky and ref without decreasing again. In the case of LFI 18 the signal decreased again. While the behaviour of LFI 18 was fully understood just from the analysis of the available data, for LFI 26 it was necessary to wait for the proposed extra test, run many days after the event. Results from this dedicated test are reported in the second part of this note

In flight evaluation of LFI radiometers thermal susceptibilities

In this technical note we provide a preliminary estimation of the impact of temperature fluctuations at the level of different thermal stages on the output signal of the Planck-LFI radiometers. Thermal susceptibilties at the level of Front End Modules (FEMs), Back End Modules (BEMs) and 4K Reference Loads have been evaluated throughout the ground test phases of the instrument. Due to bias optimization and different environmental conditions an in-flight measurement is needed to get an estimate of the temperature fluctuations impact on science and to setup an attempt of reduction of such a systematic effect by using houskeeping informations

'R-factor' excess in LFI-28

It was several times observed thet LFI28 channel shows very different values in the Main and Side arm. This note wants to investigate this feature trying to address at leas several of the many open questions regarding the origin of this beahvior and its possible causes

Support Band 2 development projects to optimize receiver components and vacuum lens INAF Final Report

Scope of this document is to report the activity @ INAF in relation to the work of the collaboration agreement No. 81231/18/88652/ADI for Support of Band 2 development projects to optimize receiver components and vacuum lens [AD 1]. Specifically, this release covers all the activities performed in agreement with the Statement of Work [AD2] and serve as a final report for the Final Review scheduled on 15 July 2019

Analysis of the thermal behaviour of the LFI-RAA cryogenic chamber in ALS

The scope of this document is to present a thermal analysis of the RAA Cryofacility used in the LFI QM Test in ALS . The data used for this analysis cover 8 days of testing: from the 18th to the 25th of July 2005. The aim of the analysis is to understand the behaviour of the LFI RAA cryogenic chamber and to provide useful indications to fully exploit the cryochamber thermal data during the instrument calibration data analysi