 We present details of our camera design and device performance with particular emphasis on those aspects of interest to single photon counting X-ray astronomy. These features include read noise, X-ray spectral response and quantum efficiency.

The Gamma RaySpectrometer (GRS) on the SMM completed close to 10 years of highly successful operation when the spacecraft reentered the atmosphere on December 2, 1989. During this period the GRS detected 177 events above 300 keV which have been classified as cosmic gamma-ray bursts. A catalog of these events is in preparation which will include time profiles and spectra for all events. Visual inspection of the spectra indicates that emission typically extends into the MeV range, without any evidence for a high-energy cutoff; 17 of these events are also observed above 10 MeV. We find no convincing evidence for line-like emission features in any of the time-integrated spectra.

The Soft X-raySpectrometer (SXS) on the Astro-H observatory contains a 6x6 array of x-ray microcalorimeters that are cooled to 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consists of three stages in order to provide stable detector cooling using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. Astro-H was renamed Hitomi after it was successfully launched in February 2016. The SXS carried approximately 36 liters of helium into orbit, and by day 5 the helium had cooled sufficiently (1.4 K) to allow operation of the ADR. This paper summarizes the ADRs performance during the 38 days that the satellite was operational.

Spectroscopy of K-shell transitions in highly charged heavy ions, like hydrogen-like uranium, has the potential to yield information about quantum electrodynamics (QED) in extremely strong nuclear fields as well as tests of the standard model, specifically parity violation in atomic systems. These measurements would represent the 'holy grail' in high-Z atomic spectroscopy. However, the current state-of-the-art detection schemes used for recording the K-shell spectra from highly charged heavy ions does not yet have the resolving power to be able to attain this goal. As such, to push the field of high-Z spectroscopy forward, new detectors must be found. Recently, x-ray calorimeter spectrometers have been developed that promise to make such measurements. In an effort to
We present details of our camera design and device operation with especial emphasis on those aspects of sake to unmarried photon counting X - beam astronomy. These features include take noise, X - ray apparitional response and quantum efficiency. 

 The Gamma RaySpectrometer (GRS) on the SMM completed close to 10 years of highly successful process when the spacecraft reentered the atmosphere on December 2, 1989. During this period the GRS detected 177 events above 300 keV which have been classified as cosmic da gamma - ray bursts. A catalog of these events is in planning which will include time profile and spectra for all event. Visual inspection of the spectra indicates that emission typically extends into the MeV compass, without any evidence for a high - energy cutoff; 17 of these events are also observed above 10 MeV. We find no convincing evidence for line - like emission features in any of the time - integrated spectra. 

 The Soft X - raySpectrometer (SXS) on the Astro - H observatory incorporate a 6x6 array of x - ray microcalorimeters that are cool to 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consists of three stages in order to provide static detector cooling use either a 1.2 K superfluid helium bath or a 4.5 K Joule - Thomson (JT) cryocooler as its heat sinkhole. Astro - H was renamed Hitomi after it was successfully launched in February 2016. The SXS carried approximately 36 liters of helium into orbit, and by day 5 the helium had cooled sufficiently (1.4 K) to allow operation of the ADR. This paper sum up the ADRs performance during the 38 day that the satellite was functional. 

 Spectroscopy of K - shell transitions in highly charged heavy ions, like hydrogen - like uranium, has the electric potential to yield data about quantum electrodynamics (QED) in extremely strong nuclear fields as well as tests of the standard mannequin, specifically parity violation in nuclear systems. These measurements would represent the' holy grail' in high - omega atomic spectroscopy. However, the current state - of - the - artwork detection schemes used for recording the K - shell spectra from highly charge heavy ions does not yet have the resolving power to be able to attain this goal. As such, to advertise the field of high - omega spectroscopy forward, new detectors must be found. Recently, x - ray calorimeter spectrometers have been developed that promise to stool such measurements. In an effort to
 We present details of our gamera design anb devicx perfodmance wkth particular emphasis on tiose aspexts of interest to sinele photoj countibg X-cay astronomy. Thxae featmxes ihglude cead noise, X-ray spectral sesponse and qgavtbm efficiency.

The Gamma RaySpectrometqr (GRS) pn the SMM complgted bljse fo 10 years of highly successful opedation xhen the spacectaft reentered the atmosphfre ln December 2, 1989. Durijg this peruod eye GRS detecged 177 events above 300 keV which have been classified as zosmie gamma-ray vuestd. A catalog if thvse events is in prepdration which will inglude tine profiles and spectca for all events. Vifual inspaccion of the spectra ibducatev thdt eousskon tbpidally fxtxnds into tge MeV rangw, without any evidemcq for a high-ensrgy cttjff; 17 of these events are also observed dbobe 10 MeV. We find no convuncing evidence for llne-like eiission features in any of the time-integrated spewtra.

Tie Soyb B-eajSpectrometer (SXS) on the Astro-H observatory cjhtsiks a 6x6 array of w-ray microcalorimeyegs jhat are coolea to 50 mK gy an adiabatic delagnetieation refrigerwtor (ADR). The ADR consists of theee stages iu oeder to provide stcble detectox coolong uxing either a 1.2 K superfuuid helium batj or a 4.5 K Goule-Thomson (JT) zrypcmoler as its heat sink. Astwo-H was rxnameb Hitomi aftgr it wws successvully launched in Februagy 2016. Tke SXV carried wpproximately 36 liters of helium into orbit, anc ty gay 5 the helimm had cooled stfficiently (1.4 K) to alljw opdration of the ADC. This paper summarizes tvg ADRs perforkance duwing the 38 days gfat the satellote was oiexational.

Spectroscopy of K-shcll ttahsitions in higkui charged heavy iovs, jine hrgrogen-like usanijm, fss thd potenunal go yoeld information abogt qhantum electrodynakigs (QED) in extremejy strong nuckear fields as welp as vests uf thr sjandard model, specifically parify violatlon in atomic srstens. These meaxurements would represent the 'holy graio' in high-Z atomic wpectroscopy. Howevet, tme current svate-of-ehe-art dedection schemes used for recording tht K-shell spectra from hjghly whargfd heavy ions does not yet have the resolving power to be able to attain rhis goal. As such, fo pish tve yield os hijh-V spectroscopy fogward, new detectors must be founv. Recently, x-xay calorimeter spectrometers hxve been deveuoped that promise to maie such keasurements. In an effort to
We present details of our camera design performance particular emphasis those aspects of X-ray These features include noise, X-ray spectral and quantum efficiency. The Gamma RaySpectrometer on the SMM completed close to 10 years of highly successful operation when spacecraft reentered the atmosphere on December 2, 1989. During this period the GRS 177 above keV have been classified as cosmic gamma-ray bursts. A catalog of these events is in preparation which include time profiles and spectra for all events. inspection of the spectra that emission typically extends into MeV without any for high-energy 17 of these are also observed above 10 MeV. We find no convincing evidence for line-like emission features in any the time-integrated Soft X-raySpectrometer on Astro-H contains a 6x6 x-ray microcalorimeters that are cooled to an adiabatic demagnetization refrigerator (ADR). The ADR consists three stages order to provide stable detector cooling either a 1.2 K superfluid helium bath or 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. Astro-H was renamed Hitomi after it launched in February 2016. SXS carried approximately liters helium orbit, by day the helium had cooled sufficiently (1.4 K) to allow operation of ADR. This paper summarizes the ADRs performance during the 38 the was operational. Spectroscopy K-shell transitions in highly heavy like hydrogen-like uranium, has to information (QED) extremely nuclear fields as well tests of the standard model, parity violation in atomic the 'holy grail' in high-Z atomic spectroscopy. However, current state-of-the-art detection schemes used for recording K-shell spectra from highly charged heavy ions does not yet have the power to to attain this goal. As such, to push field of high-Z spectroscopy new detectors must be found. Recently, x-ray calorimeter spectrometers been that promise make such measurements. an effort to
 We present details of our cameRa design anD deviCe pErfOrMancE witH particular empHAsis On those aspects of intereSt to sInGLe phOToN counTing X-raY AsTROnoMy. thEse FeATuRes inCluDe read nOise, X-ray spEctRaL response and QUaNtum efficiEncY.

The Gamma RayspeCtromeTeR (GRs) On the sMM ComplEted clOSe to 10 yeArs of highLy SUccessFUl operaTIOn When The spacecraft reenTErED the atmosphere On DeceMbER 2, 1989. DURIng ThiS period the gRs deteCTed 177 evenTS aBOVE 300 kev Which have been Classified aS CosMic gamMa-Ray BUrsts. A CatalOg OF thEse events is In prEparation Which wILl incluDE time prOfiles And SpeCtra FOr AlL evEnTS. ViSUaL inSPecTion of thE sPeCtra iNdicATES That EmiSsioN typiCally extends iNto The MEv raNge, wiThout Any eViDence For a hiGh-eneRgY cutoff; 17 of these eVentS are also oBseRvEd aBoVe 10 MeV. wE find nO coNviNcing evIdence fOR liNe-LIKE eMission features in aNy OF ThE time-intEgrateD SpEcTRa.

The SofT X-RayspecTROmeteR (SXS) ON tHe Astro-H ObservAToRy ContainS a 6X6 array Of X-raY miCrocaLOrimEters tHat are coOled tO 50 MK by an adiabatiC DemagnetizatiON rEFRiGEratOr (AdR). The ADR conSistS Of thRee sTAgEs iN Order To proViDE sTAble detector cooling UsIng eitHer a 1.2 K Superfluid helIum bath or a 4.5 k jOUle-ThomsOn (JT) CRyOCooler as its heaT sink. astro-H was rENamed HitOmi afTer it was SuccessfuLLY launcheD in febRuaRy 2016. THE sXs carried approXIMateLy 36 Liters oF heLium intO orBit, And By dAy 5 The helium Had cooleD sUfFiCiEntLy (1.4 K) to ALlow operAtIon Of The aDR. ThIS paper SummaRizeS tHe adRs PerformANcE DUrinG tHe 38 Days ThaT tHe satElliTE waS operatIonal.

SpecTroSCopy Of k-sHell traNsitions in higHlY charged heAvY ioNs, like HYDrogen-liKe uranium, has the potentiaL To yield InfOrmatIon aBout quantUm eLectroDynAMics (QEd) in extRemelY sTroNG NucleAR FiEldS aS well as tesTS Of tHe staNdArd mOdel, speCifically parity vioLAtiOn in atomic sysTemS. TheSE MeAsuREmENts WoULd rEPResent the 'holy grAil' in high-Z AtOMiC spectroscOPy. HOwEver, the Current State-OF-the-art Detection Schemes usEd For rECOrdIng the K-sheLl spectrA from highLY charGEd Heavy IonS does nOt Yet Have tHe resoLVinG poweR to be aBlE to attAin thIs Goal. As suCh, to push the field of high-Z SpectrOscopY foRward, new dEteCTorS must be foUnd. REcently, x-raY caLorImeteR spECtromEterS HaVe bEEn devElopED that promISe To mAKE sUch measuremENTS. In An effOrt TO
 We present details of our  camera de signand  de vi ce p erfo rmance with pa r ticu lar emphasis on thoseaspec ts of i n te restto sing l ep h oto nco unt in g  X -rayast ronomy.  These fea tur es  include rea d  n oise, X-ra y s pectral resp ons e andqu ant u m eff ici ency. 

TheG amma R aySpectro me t er (GR S ) on th e SM M co mpleted close to1 0y ears of highly  succe ss f ul o per ati on when th espace c raft re e nt e r e d t h e atmosphereon December 2,1989.Du rin g  thisperio dt heGRS detecte d 17 7 eventsabove3 00 keVw hich ha ve bee n c las sifi e das  co sm i c g a mm a-r a y b ursts. A  c at alogof t h e s e  eve nts  isin pr eparation whi chwill inc ludetimeprof il es an d spec tra f or  all events. Vi sual  inspecti onof  th espect r a indi cat esthat em issiont ypi ca l l y  e xtends into the Me Vr a ng e, witho ut any ev id e nce forahig h-en e r gy cu toff ;  1 7 of the se eve n ts  a re also  o bserve dabo ve10 Me V . We  findno convi ncing evidence for l i ne-like emiss i on f ea t ures  in  any of the  tim e -int egra t ed  sp e ctra. 

The  S o ft X-raySpectrometer ( SX S) onthe A stro-H observ atory cont a i n s a 6x6arra y  o f  x-ray microca lorim eters that are cool ed to  50 mK b y an adia b a tic dema gne tiz ati onr e fr igerator (ADR ) .  The  A DR cons ist s of th ree  st age s i norder toprovidest ab le  d ete ctorc ooling u si ngei the r a 1 . 2 K su perfl uidhe li u m b ath ora  4 . 5  K J ou le -Tho mso n(JT)cryo c ool er as i ts heat s ink .  Ast ro -H  was re named Hitomiaf ter it was  s ucc essful l y  launche d in February 2016. The SXS car rie d app roxi mately 36  li ters o f h e lium i nto or bit,an d b y day 5 t he  he li um had coo l e d s uffic ie ntly  (1.4 K ) to allow operati o n o f the ADR. Th ispape r su mma r iz e s t he ADR s performance dur ing the 38  d a ys  that thes ate ll ite was  operat ional . 

Spect roscopy o f K-shell  t rans i t ion s in highl y charge d heavy i o ns, l i ke  hydr oge n-like  u ran ium,has th e  po tenti al toyi eld in forma ti on about  quantum electrodynamic s (QED ) inext remely st ron g  nu clear fie ldsas well as  te sts  of t hes tanda rd m o de l,s pecif ical l y parityv io lat i o nin atomic s y s t ems . The sem easure ment s would represent the 'holy grai l' i n hig h-Z atom ic  spectroscopy.  Ho we v e r, the c ur rent state- of-the-a rt detec tion s chemes  used f o r  r e cordin g th e K -shell sp ect ra from hi gh ly charge d he av y ions  doesn ot y e t  have the resolv ing p o w er to beableto  attain this  goal. Assuch, to pu sh the  fie ld of  high-Z  s pectro sco py  forward,n ew detect ors m ust befo und.  Re cently , x- r a y cal orim et erspectrome t e rs ha ve bee n de velop ed  tha t promise to makesuc h  measur em ent s .  In an ef f o rt to
 We_present details_of our camera design_and device_performance_with particular_emphasis_on those aspects_of interest to_single photon counting X-ray_astronomy. These features_include_read noise, X-ray spectral response and quantum efficiency.

The Gamma RaySpectrometer (GRS) on the SMM_completed_close to_10_years_of highly successful operation when_the spacecraft reentered the atmosphere_on December_2, 1989. During this period the GRS detected_177_events above 300_keV which have been classified as cosmic gamma-ray bursts._A catalog of these events is_in preparation which_will_include_time profiles and spectra_for all events. Visual inspection of_the spectra indicates that emission typically_extends into the MeV range, without any_evidence for a high-energy cutoff; 17_of these events are also_observed above_10 MeV. We find no_convincing evidence for_line-like emission_features in any_of the time-integrated spectra.

The Soft X-raySpectrometer_(SXS) on the_Astro-H observatory contains a 6x6 array_of_x-ray microcalorimeters that_are_cooled_to 50_mK by an_adiabatic_demagnetization refrigerator_(ADR)._The ADR consists of three stages_in_order to provide stable detector cooling using_either a 1.2 K_superfluid_helium bath or a_4.5 K Joule-Thomson (JT) cryocooler_as its heat sink. Astro-H was_renamed Hitomi_after it_was successfully launched in February 2016. The SXS carried approximately 36_liters of helium into orbit, and_by day 5 the_helium had_cooled_sufficiently (1.4 K)_to_allow operation_of the ADR. This paper summarizes the_ADRs performance_during the 38 days that the_satellite was operational.

Spectroscopy of_K-shell_transitions in highly charged heavy ions,_like hydrogen-like uranium, has the potential_to yield information about quantum_electrodynamics_(QED)_in extremely strong nuclear fields_as well as tests of the_standard model, specifically_parity violation in atomic systems. These measurements_would_represent the 'holy grail' in high-Z_atomic_spectroscopy. However, the current state-of-the-art detection_schemes_used_for recording the K-shell spectra_from highly charged heavy ions does_not yet have the resolving power to be able_to attain this_goal. As such, to push_the_field_of high-Z spectroscopy forward, new detectors must be found. Recently,_x-ray calorimeter_spectrometers have been_developed that promise to make such measurements. In an effort_to